Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/10/15


AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
304 PM CDT SAT AUG 8 2015 .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT A FEW ISOLATED SHOWERS AND THUNDERSTORMS HAVE POPPED UP ACROSS THE STATE DURING THE LAST COUPLE OF HOURS AND THESE HAVE BEEN EXTREMELY ISOLATED IN NATURE. WITH A STALLED BOUNDARY ACROSS THE STATE...DO EXPECT A FEW MORE SHOWERS AND THUNDERSTORMS TO POP UP IN THE HEAT OF THE DAY...WHICH THE HRRR HAS BEEN CONSISTENT IN SHOWING AS WELL. SUNDAY WILL BE SLIGHTLY HOTTER AS THE RIDGE BUILDS INTO THE AREA...THE AXIS OF HIGHEST DEW POINTS WILL SHIFT A BIT MORE TO THE EAST. AS A RESULT...THIS WILL ADD NE ARKANSAS INTO THE HEAT ADVISORY. A HOT DAY CAN BE EXPECTED ON MONDAY AS WELL WITH SLIGHTLY LOWER DEW POINTS. AT THIS POINT IT APPEARS THE ONLY AREAS ABLE TO REACH EXCESSIVE HEAT WARNING CRITERIA WILL BE ACROSS SE PORTIONS OF THE CWA...BUT AT THIS POINT ITS BORDERLINE. WILL DEFER TO THE MID SHIFT...AS THE NUMBERS ARE SO CLOSE TO CRITERIA. A FRONT WILL MOVE THROUGH THE STATE ON MONDAY...WITH LITTLE IN THE WAY OF PRECIPITATION EXPECTED UNTIL THE FRONT REACHES SOUTHERN ARKANSAS. IT CONTINUES TO LOOK THAT THE BEST CHANCES FOR PRECIPITATION WILL BE TO THE SOUTH OF THE STATE...BUT DID GO AND INCLUDE SLIGHT CHANCE POPS ACROSS SOUTHERN PORTIONS OF THE STATE. && .LONG TERM...WEDNESDAY THROUGH FRIDAY SOME EXCESSIVE HEAT RELIEF IS IN STORE BEGINNING WEDNESDAY. AS THE UPPER RIDGE SHIFTS WEST ALLOWING AND IN THE WAKE OF A WEAK COLD FRONT MAX TEMPS DURING THIS PERIOD WILL RUN AT OR BELOW NORMAL. DRIER CONDITIONS AS WELL AS DEWPOINTS FALL INTO THE UPPER 50S TO MID 60S. LOOKS TO BE A DRY PERIOD AS STABLE NORTHERLY FLOW ALOFT AND WEAK NE SURFACE FLOW DOMINATE AND EMBEDDED UPPER LEVEL DISTURBANCES SEEM UNLIKELY AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 92 74 99 79 / 10 0 0 10 CAMDEN AR 103 77 104 78 / 20 0 0 10 HARRISON AR 94 74 97 74 / 20 0 0 10 HOT SPRINGS AR 102 78 103 78 / 20 0 0 10 LITTLE ROCK AR 100 77 103 80 / 10 0 0 10 MONTICELLO AR 102 77 103 80 / 10 0 0 10 MOUNT IDA AR 102 75 102 74 / 20 0 0 10 MOUNTAIN HOME AR 93 74 98 75 / 20 0 0 10 NEWPORT AR 92 73 98 77 / 10 0 0 10 PINE BLUFF AR 100 76 103 78 / 10 0 0 10 RUSSELLVILLE AR 99 76 101 75 / 20 0 0 10 SEARCY AR 95 73 100 76 / 10 0 0 10 STUTTGART AR 96 75 101 77 / 10 0 0 10 && .LZK WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR BAXTER-BOONE- CLEBURNE-INDEPENDENCE-JACKSON-MARION-MONROE-NEWTON-SEARCY-STONE- VAN BUREN-WOODRUFF. HEAT ADVISORY FROM 11 AM TO 8 PM CDT SUNDAY FOR BAXTER-BOONE- CLEBURNE-FULTON-INDEPENDENCE-IZARD-JACKSON-MARION-NEWTON-SEARCY- SHARP-STONE-VAN BUREN. EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR ARKANSAS- BRADLEY-CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA-DREW- FAULKNER-GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN- LOGAN-LONOKE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK-POPE-PRAIRIE- PULASKI-SALINE-SCOTT-WHITE-YELL. EXCESSIVE HEAT WARNING FROM 11 AM TO 8 PM CDT SUNDAY FOR ARKANSAS-BRADLEY-CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA- DREW-FAULKNER-GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN- LOGAN-LONOKE-MONROE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK-POPE- PRAIRIE-PULASKI-SALINE-SCOTT-WHITE-WOODRUFF-YELL. HEAT ADVISORY FROM 11 AM TO 8 PM CDT MONDAY FOR ARKANSAS-BRADLEY- CALHOUN-CLARK-CLEBURNE-CLEVELAND-CONWAY-DALLAS-DESHA-DREW- FAULKNER-GARLAND-GRANT-HOT SPRING-JACKSON-JEFFERSON-JOHNSON- LINCOLN-LOGAN-LONOKE-MONROE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK- POPE-PRAIRIE-PULASKI-SALINE-SCOTT-VAN BUREN-WHITE-WOODRUFF-YELL. && $$ SHORT TERM...65 / LONG TERM...32
AREA FORECAST DISCUSSION...UPDATE FOR AVIATION
NWS LITTLE ROCK AR
1245 AM CDT SAT 8 2015 .AVIATION... OVERALL VFR FLIGHT CONDITIONS ARE EXPECTED OVERNIGHT...ALTHOUGH PATCHY MVFR CEILINGS WILL BE SEEN...ESPECIALLY OVER NORTHERN AR. SOME FOG WILL ALSO BE POSSIBLE WITH SCATTERED MVFR CONDITIONS. A WEAK AND STALLED FRONTAL BOUNDARY WILL SPLIT THE STATE...WITH WINDS NE TO E AT 3 TO 8 MPH OVER NORTHERN TO CENTRAL AR...WHILE S TO SW 3 TO 8 MPH OVER SOUTHERN AR. AN ISOLATED SHOWER OR THUNDERSTORM MAY BE SEEN...BUT CONFIDENCE IS LOW AND DID NOT INCLUDE IN TAFS. SATURDAY WILL SEE VFR CONDITIONS WITH OVERALL DRY WEATHER. && .PREV DISCUSSION... /ISSUED 957 PM CDT FRI AUG 7 2015/ .UPDATE... SFC DATA INDC THAT THE QUASI-STATIONARY BNDRY BISECTED THE FA ALONG THE AR RVR THIS EVENING. SFC DEWPOINTS CONT TO POOL ALONG AND N OF THE BNDRY...WHERE READINGS ARE HOVERING ARND 80F. AIRMASS RMNS VERY UNSTABLE IN THIS SECTOR AS WELL...WITH 08/00Z KLZK RAOB SHOWING SBCAPE APCHG 6K J/KG WITH LTL IN THE WAY OF CINH. STARTING TO SEE SOME SCTD CONVECTION DVLP OVR FAR ERN AR ATTM. THE RAPID UPDATE MODEL DATA CONT TO INDC SCTD CONVECTION FORMING FURTHER NWWD INTO PARTS OF NERN AR LATE THIS EVENING INTO THE OVERNIGHT HOURS. PLAN TO KEEP SLGT CHC POPS IN PLACE PER GOING FCST AND WL CONT TO MONITOR RADAR/MODEL TRENDS. THUS...NO SIG CHGS WERE MADE TO THE CURRENT FCST. JUST UPDATED HRLY TEMPS TO ACCOUNT FOR LATEST TRENDS. ALL UPDATES OUT. /44/ && PREV DISCUSSION... /ISSUED 239 PM CDT FRI AUG 7 2015/ SHORT TERM...TONIGHT THROUGH MONDAY NIGHT AN AREA OF SHOWERS AND THUNDERSTORMS MOVED FROM SOUTH CENTRAL MISSOURI AND TRACKED SOUTHEAST THROUGH PORTIONS OF EASTERN ARKANSAS. THESE STORMS CONTINUED TO STRENGTHEN DURING THE MID MORNING HOURS AND LED TO INCREASED CLOUD COVER THROUGH THE EASTERN HALF OF THE STATE. BY THE EARLY AFTERNOON HOURS...MOSTLY SUNNY SKIES WERE SEEN AROUND THE STATE WITH TEMPERATURES WARMING INTO THE MID TO UPPER 90S WITH A FEW LOCATIONS IN WESTERN ARKANSAS ALREADY TOPPING 100 DEGREES. HEAT INDICES AROUND THE STATE HAVE REACHED 112 AT RUSSELLVILLE WITH A FEW LOCATIONS TOPPING 110. FOR TONIGHT...KEPT SLIGHT CHANCE POPS ACROSS EASTERN PORTIONS OF THE AREA WITH BOTH THE HRRR AND WRF SHOWING REDEVELOPMENT ACROSS EASTERN ARKANSAS. IN THE COMING DAYS...WILL CONTINUE TO SEE A STRONG RIDGE OF HIGH PRESSURE BUILD INTO THE REGION WITH TEMPERATURES EXPECTED TO CLIMB EVEN HOTTER THAN WHAT HAS BEEN SEEN TODAY. FOR NOW...HAVE EXTENDED AND EXPANDED THE EXCESSIVE HEAT WARNING INTO SATURDAY AND CONTINUED WITH THE HEAT ADVISORY AT THE REMAINING COUNTIES EXCEPT ACROSS NORTHEAST ARKANSAS. HOT TEMPERATURES WILL CONTINUE ON SUNDAY WITH FEWER CLOUDS AND SLIGHTLY LOWER DEWPOINTS...GENERALLY ACROSS SOUTHWEST AND CENTRAL ARKANSAS. HOWEVER DEWPOINTS WILL GENERALLY INCREASE ACROSS NORTHEAST ARKANSAS WHICH WILL LIKELY CAUSE HEAT ADVISORIES/WARNINGS TO BE EXTENDED AND EXPANDED. UPPER LEVEL RIDGE WILL BEGIN TO RETREAT ON MONDAY...ALLOWING A COLD FRONT TO APPROACH THE STATE FROM THE NORTH. AT THIS POINT...IT DOES NOT APPEAR THAT THERE WILL BE HIGH CHANCE FOR PRECIPITATION WITH THIS FRONT...BUT SLIGHTLY COOLER TEMPS AND DRIER AIR WILL MOVE INTO THE STATE FOR THE LONG TERM. LONG TERM...TUESDAY THROUGH FRIDAY NIGHT THE UPPER LEVEL RIDGE OF HIGH PRESSURE THAT HAS PERSISTED OVER THE REGION FOR THE PAST SEVERAL WEEKS WILL RETREAT WESTARD DURING THE EXTENDED TERM...CHANGING THE UPPER LEVEL FLOW PATTERN TO A NORTHERLY TO NORTHWESTERLY FLOW. AT THE SURFACE A HIGH PRESSURE SYSTEM WILL SLOWLY MOVE TO THE EAST ACROSS THE UPPER MIDWEST INTO THE OHIO VALLEY...KEEPING THE FORECAST AREA ALONG THE SOUTHERN PERIPHERY OF THE HIGH. THIS WILL RESULT IN A DRY NORTHERLY TO NORTHEASTERLY SURFACE FLOW. THIS SETUP WILL ALLOW TEMPERATURES TO REMAIN JUST A BIT COOLER THAN THEY HAVE BEEN AT PRESENT...MOST NOTABLY ACROSS THE NORTHERN HALF OF THE AREA. SURFACE DEWPOINTS WILL EVENTUALLY DROP DOWN TO BE ABOUT 10 TO 15 DEGREES LOWER THAN THEY ARE RIGHT NOW...WHICH WILL BE A WELCOME RELIEF...PUSHING MAXIMUM APPARENT TEMPERATURES DOWN INTO THE MID 80S ACROSS THE NORTH TO THE MID 90S ACROSS THE SOUTH. WITH THE NORTH TO NORTHWESTERLY FLOW AT THE UPPER LEVELS...A SHORTWAVE OR TWO COULD RIPPLE ACROSS THE FORECAST AREA DURING THE EXTENDED TERM...AND ISOLATED SHOWERS AND THUNDERSTORMS CANNOT BE RULED OUT. HOWEVER...WITH THE MOISTURE LEVELS REMAINING LOWER...THE CHANCES FOR PRECIPITATION SHOULD BE RATHER LOW...AND BELOW MENTION IN MANY AREAS. && .LZK WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM 7 AM SATURDAY TO 7 PM CDT SUNDAY FOR BAXTER- BOONE-INDEPENDENCE-JACKSON-MARION-NEWTON-SEARCY-STONE. EXCESSIVE HEAT WARNING UNTIL 7 PM CDT SATURDAY FOR BRADLEY- CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA-DREW-FAULKNER- GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN-LOGAN-LONOKE- OUACHITA-PERRY-POPE-PULASKI-SALINE-YELL. EXCESSIVE HEAT WARNING FROM 7 AM TO 7 PM CDT SATURDAY FOR ARKANSAS-MONTGOMERY-PIKE-POLK-PRAIRIE-SCOTT-WHITE. HEAT ADVISORY UNTIL 7 AM CDT SATURDAY FOR ARKANSAS-MONTGOMERY- PIKE-POLK-PRAIRIE-SCOTT-WHITE. HEAT ADVISORY UNTIL 7 PM CDT SUNDAY FOR CLEBURNE-MONROE-VAN BUREN-WOODRUFF. && $$
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
245 PM MST SAT AUG 8 2015 .UPDATE...TO AVIATION AND FIRE WEATHER DISCUSSIONS... && .SYNOPSIS... ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE EAST OF PHOENIX TONIGHT...BUT STORM CHANCES WILL WANE ACROSS THE ENTIRE AREA ON SUNDAY AS DRIER AIR MOVES INTO THE AREA. A RETURN TO A MORE TYPICAL MONSOON FLOW IS EXPECTED BY THE MIDDLE OF NEXT WEEK...ALTHOUGH DRIER AIR IS ONCE AGAIN FORECAST TO OVERSPREAD THE AREA BY THE END OF THE WEEK. && .DISCUSSION... LATEST STREAMLINE ANALYSIS SHOWS A WELL-DEFINED SOUTHWESTERLY FLOW IN THE 850 TO 300 MB LAYER BETWEEN A LOW PRESSURE SYSTEM ACROSS THE NORTHERN ROCKIES AND AN ANTICYCLONE ACROSS TX. DRIER AIR CONTINUES TO OVERSPREAD THE AREA AND IS MOST PRONOUNCED FURTHER WEST. AT THE SURFACE...DEWPOINTS REMAIN ELEVATED IN THE WAKE OF YESTERDAY`S RAINFALL...AND ARE AS HIGH AS MID TO UPPER 60S ACROSS THE PHOENIX AREA. LATEST SATELLITE IMAGERY AND REGIONAL WEBCAMS INDICATE THAT CU IS STRUGGLING TO DEVELOP VERTICALLY ACROSS THE LOWER DESERTS. THIS IS LIKELY DUE TO DRY AIR IN THE 850-750 MB LAYER AND A WARM BULGE AROUND 700 MB EVIDENT IN SEVERAL ACARS PHX SOUNDINGS. LATEST MESOANALYSIS IS THEREFORE LIKELY OVERESTIMATING INSTABILITY ACROSS CENTRAL AZ. LATEST RUNS OF THE HRRR CONTINUE TO INITIATE CONVECTION TOO EARLY AND SUBSEQUENTLY DELAY THE ONSET OF ISOLATED SHOWERS AND THUNDERSTORMS LATER IN THE AFTERNOON. A SLIGHT CHANCE OF THUNDERSTORMS WILL PERSIST INTO THIS EVENING...THOUGH THE BEST CHANCE WILL MAINLY BE CONFINED TO THE HIGHER TERRAIN EAST OF PHOENIX IN THE VICINITY OF THE DEEPER MOISTURE. CONSENSUS OF THE LATEST LOCAL/NCEP/U OF AZ WRFS ALSO SUGGEST NEGLIGIBLE CHANCES OF RAINFALL OR THUNDERSTORM-RELATED IMPACTS THROUGH THIS EVENING. && .PREVIOUS DISCUSSION... DRIER AIR WILL ALMOST CERTAINLY OVERSPREAD THE ENTIRE AREA BY LATE TONIGHT...EFFECTIVELY PUTTING THE BRAKES ON WIDESPREAD MONSOON CONVECTION FOR THE NEXT SEVERAL DAYS. WHILE THERE WILL BE SMALL POCKETS OF MOISTURE IN THE MOUNTAINS EAST OF PHOENIX...INSTABILITY AND A SUFFICIENT TRIGGER APPEAR TO BE LACKING. A RETURN TO A MORE TYPICAL MONSOON PATTERN IS EXPECTED BY TUESDAY/WEDNESDAY AND THIS MORNING`S GFS AND ECMWF /AND ENSEMBLES/ SUGGEST AN IMPRESSIVE INCREASE IN MOISTURE. NOT ONLY THAT...BUT THEY ALSO DEPICT A FAST MOVING 250-300MV PV ANOMALY IN THE AREA TUESDAY AFTERNOON. INHERITED FORECAST DEPICTED ELEVATED POPS AND I SEE NO REASON TO REVERSE THIS THINKING. WITH MOISTURE FORECAST TO REMAIN IN PLACE ON WEDNESDAY AS WELL...BOTH DAYS COULD BE ACTIVE AT SOME POINT OR ANOTHER. WEDNESDAY`S POPS ARE A BIT MORE BROAD-BRUSHED THAN I`D LIKE BUT THERE`S ALWAYS A POSSIBILITY OF A REMNANT MCV TO KICK OFF CONVECTION. A BIT ATYPICAL FROM WHAT ONE WOULD EXPECT NORMALLY...BUT THE BL WILL BEGIN TO DRY OUT FROM THURSDAY ONWARD DESPITE NORMALLY FAVORABLE EASTERLY FLOW IN THE MID LEVELS. RATHER THAN PULLING MOISTURE NORTHWARD FROM THE GULF OF CALIFORNIA...IT WOULD APPEAR THE UPPER RIDGE WILL MIGRATE NORTHWARD AND ADVECT A DRY AIRMASS FROM TEXAS/NEW MEXICO INTO PLACE BY THE END OF THE WEEK. DIDN`T WANT TO BUY INTO THIS DRYING TREND AT FACE VALUE SINCE THE ENSEMBLES MAINTAIN SOME DEGREE OF MOISTURE ACROSS THE AREA /AND SLIGHT VEERING IN THE MID LEVEL FLOW WOULD KEEP MOISTURE IN PLACE/...THUS I MAINTAINED LOW END CLIMO-LIKE POPS THROUGH THE END OF THE WEEK. IF DRY AIR ENDS UP MATERIALIZING AS ADVERTISED IN THE DETERMINISTIC GUIDANCE...TEMPERATURES WILL ALMOST CERTAINLY ECLIPSE THE 110 DEGREE MARK ACROSS THE DESERTS AND I STARTED NUDGING HIGHS UP A BIT LATE IN THE FORECAST. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... MAJORITY OF THE MONSOON STORM ACTIVITY WILL REMAIN ACROSS EASTERN AZ TONIGHT...WITH ONLY THE SLIGHTEST OF CHANCES OF ANY ACTIVITY SURVIVING INTO THE PHX METRO THIS EVENING. MONSOON MOISTURE BOUNDARY REMAINS ACROSS THE SOUTH-CENTRAL AZ DESERTS...GENERATING THE CU FIELDS WITH A STRAY...COMPACT...BUT SHORT-LIVED SHOWER OR TWO SQUEEZING OUT OF THE TALLEST CU...HENCE THE VCSH IN THE KIWA TAF. SKIES WILL GRADUALLY CLEAR INTO THE EVENING...WITH SOME FEW MID LEVEL CIGS LINGERING. MOSTLY LIGHT WINDS TO CONTINUE INTO THE EVENING...TAKING UP SWTSRLY HEADINGS LATER INTO THE AFTN AND MAINTAINING THOSE LATER INTO THE EVENING THAN TYPICAL. SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... MOSTLY CLEAR SKIES AND PERIODS OF ELEVATED WEST TO SW WINDS TO PERSIST FOR THE TAF PERIODS AS DRY AIR CONTINUES TO MOVE INTO THE AREA FROM THE WEST. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... TUESDAY THROUGH SATURDAY... A SUBTLE RETURN OF MONSOON MOISTURE COUPLED WITH SOME PASSING UPPER LEVEL DISTURBANCES FROM THE SOUTHEAST WILL RAISE STORM CHANCES AND HUMIDITIES FOR TUESDAY. STORM CHANCES WILL EXPAND OUT OF THE EASTERN AZ HIGHER TERRAIN THROUGH THE LOWER DESERT LOCALES AND TOWARDS THE CO RIVER VALLEY. CONDITIONS DRY OUT AGAIN BY THE MIDDLE PART OF THE WEEK AND DAYTIME TEMPERATURES RESPOND IN KIND...WITH THE POTENTIAL TO GO ABOVE SEASONALLY NORMAL READINGS. WINDS WILL BE LIGHT THROUGH MUCH OF THE PERIOD FOLLOWING TYPICAL DIURNAL DIRECTIONS EXCEPT FOR AFTERNOON UPSLOPE BREEZES GUSTING AT TIMES UP TO 20 MPH. && .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...HIRSCH PREVIOUS DISCUSSION...LEINS AVIATION...NOLTE FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
212 PM MST SAT AUG 8 2015 .SYNOPSIS... ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE EAST OF PHOENIX TONIGHT...BUT STORM CHANCES WILL WANE ACROSS THE ENTIRE AREA ON SUNDAY AS DRIER AIR MOVES INTO THE AREA. A RETURN TO A MORE TYPICAL MONSOON FLOW IS EXPECTED BY THE MIDDLE OF NEXT WEEK...ALTHOUGH DRIER AIR IS ONCE AGAIN FORECAST TO OVERSPREAD THE AREA BY THE END OF THE WEEK. && .DISCUSSION... LATEST STREAMLINE ANALYSIS SHOWS A WELL-DEFINED SOUTHWESTERLY FLOW IN THE 850 TO 300 MB LAYER BETWEEN A LOW PRESSURE SYSTEM ACROSS THE NORTHERN ROCKIES AND AN ANTICYCLONE ACROSS TX. DRIER AIR CONTINUES TO OVERSPREAD THE AREA AND IS MOST PRONOUNCED FURTHER WEST. AT THE SURFACE...DEWPOINTS REMAIN ELEVATED IN THE WAKE OF YESTERDAY`S RAINFALL...AND ARE AS HIGH AS MID TO UPPER 60S ACROSS THE PHOENIX AREA. LATEST SATELLITE IMAGERY AND REGIONAL WEBCAMS INDICATE THAT CU IS STRUGGLING TO DEVELOP VERTICALLY ACROSS THE LOWER DESERTS. THIS IS LIKELY DUE TO DRY AIR IN THE 850-750 MB LAYER AND A WARM BULGE AROUND 700 MB EVIDENT IN SEVERAL ACARS PHX SOUNDINGS. LATEST MESOANALYSIS IS THEREFORE LIKELY OVERESTIMATING INSTABILITY ACROSS CENTRAL AZ. LATEST RUNS OF THE HRRR CONTINUE TO INITIATE CONVECTION TOO EARLY AND SUBSEQUENTLY DELAY THE ONSET OF ISOLATED SHOWERS AND THUNDERSTORMS LATER IN THE AFTERNOON. A SLIGHT CHANCE OF THUNDERSTORMS WILL PERSIST INTO THIS EVENING...THOUGH THE BEST CHANCE WILL MAINLY BE CONFINED TO THE HIGHER TERRAIN EAST OF PHOENIX IN THE VICINITY OF THE DEEPER MOISTURE. CONSENSUS OF THE LATEST LOCAL/NCEP/U OF AZ WRFS ALSO SUGGEST NEGLIGIBLE CHANCES OF RAINFALL OR THUNDERSTORM-RELATED IMPACTS THROUGH THIS EVENING. && .PREVIOUS DISCUSSION... DRIER AIR WILL ALMOST CERTAINLY OVERSPREAD THE ENTIRE AREA BY LATE TONIGHT...EFFECTIVELY PUTTING THE BRAKES ON WIDESPREAD MONSOON CONVECTION FOR THE NEXT SEVERAL DAYS. WHILE THERE WILL BE SMALL POCKETS OF MOISTURE IN THE MOUNTAINS EAST OF PHOENIX...INSTABILITY AND A SUFFICIENT TRIGGER APPEAR TO BE LACKING. A RETURN TO A MORE TYPICAL MONSOON PATTERN IS EXPECTED BY TUESDAY/WEDNESDAY AND THIS MORNING`S GFS AND ECMWF /AND ENSEMBLES/ SUGGEST AN IMPRESSIVE INCREASE IN MOISTURE. NOT ONLY THAT...BUT THEY ALSO DEPICT A FAST MOVING 250-300MV PV ANOMALY IN THE AREA TUESDAY AFTERNOON. INHERITED FORECAST DEPICTED ELEVATED POPS AND I SEE NO REASON TO REVERSE THIS THINKING. WITH MOISTURE FORECAST TO REMAIN IN PLACE ON WEDNESDAY AS WELL...BOTH DAYS COULD BE ACTIVE AT SOME POINT OR ANOTHER. WEDNESDAY`S POPS ARE A BIT MORE BROAD-BRUSHED THAN I`D LIKE BUT THERE`S ALWAYS A POSSIBILITY OF A REMNANT MCV TO KICK OFF CONVECTION. A BIT ATYPICAL FROM WHAT ONE WOULD EXPECT NORMALLY...BUT THE BL WILL BEGIN TO DRY OUT FROM THURSDAY ONWARD DESPITE NORMALLY FAVORABLE EASTERLY FLOW IN THE MID LEVELS. RATHER THAN PULLING MOISTURE NORTHWARD FROM THE GULF OF CALIFORNIA...IT WOULD APPEAR THE UPPER RIDGE WILL MIGRATE NORTHWARD AND ADVECT A DRY AIRMASS FROM TEXAS/NEW MEXICO INTO PLACE BY THE END OF THE WEEK. DIDN`T WANT TO BUY INTO THIS DRYING TREND AT FACE VALUE SINCE THE ENSEMBLES MAINTAIN SOME DEGREE OF MOISTURE ACROSS THE AREA /AND SLIGHT VEERING IN THE MID LEVEL FLOW WOULD KEEP MOISTURE IN PLACE/...THUS I MAINTAINED LOW END CLIMO-LIKE POPS THROUGH THE END OF THE WEEK. IF DRY AIR ENDS UP MATERIALIZING AS ADVERTISED IN THE DETERMINISTIC GUIDANCE...TEMPERATURES WILL ALMOST CERTAINLY ECLIPSE THE 110 DEGREE MARK ACROSS THE DESERTS AND I STARTED NUDGING HIGHS UP A BIT LATE IN THE FORECAST. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... THE UPPER LOW THAT HELPED TO DRAW MONSOON MOISTURE...AND CONSIDERABLE SHOWER/THUNDERSTORM ACTIVITY INTO THE GREATER PHOENIX AREA FRIDAY AFTERNOON/EVENING IS NOW MOVING AWAY FROM THE REGION...INTO NE NV/SW ID. AS THIS LOW CENTER MOVES AWAY...DRIER SOUTHWESTERLY FLOW IS EXPECTED TO OVERSPREAD SOUTH-CENTRAL ARIZONA...WITH A HIGH PROBABILITY THAT THUNDERSTORM ACTIVITY WILL REMAIN WELL EAST OF THE PHOENIX AREA TERMINALS TODAY. CURRENT BKN- OVC CIGS ARE EXPECTED TO BECOME FEW-SCT BY THIS AFTERNOON/EVENING. WINDS TO REVERT BACK TO TYPICAL DIURNAL TRENDS...BUT WITH WESTERLY WINDS LINGERING LATER INTO THE EVENING HOURS THEN WHAT IS NORMALLY SEEN THIS TIME OF YEAR. SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... DRY SOUTHWESTERLY FLOW ALOFT TO KEEP SKIES MAINLY CLEAR THROUGH THE TAF PERIOD. WINDS TO REMAIN MAINLY FROM A WESTERLY DIRECTION AT KIPL AND FROM A SOUTH-SOUTHWESTERLY DIRECTION AT KBLH THROUGH THE TAF PERIOD. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... MONDAY THROUGH FRIDAY... INCREASING MOISTURE INTO EARLY NEXT WEEK WILL PUSH CHANCES OF SHOWERS AND THUNDERSTORMS INTO THE SOUTHERN AND WESTERN ARIZONA DESERTS. MINIMUM RELATIVE HUMIDITIES OF 10 TO 20 PERCENT RANGE WILL BE COMMON ACROSS THE DESERTS THIS WEEKEND WITH SOME IMPROVEMENT GOING INTO EARLY NEXT WEEK. DRIEST LOCATION WILL BE SOUTHEAST CALIFORNIA THIS WEEKEND WITH MINIMUM RH VALUES INTO THE SINGLE DIGITS. HIGH TEMPERATURES WILL BE AROUND OR SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. WINDS WILL BE LIGHT THROUGH MUCH OF THE PERIOD FOLLOWING TYPICAL DIURNAL DIRECTIONS EXCEPT FOR AFTERNOON UPSLOPE BREEZES GUSTING AT TIMES UP TO 20 MPH. && .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...HIRSCH PREVIOUS DISCUSSION...LEINS AVIATION...PERCHA FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
935 PM MST FRI AUG 7 2015 .SYNOPSIS...ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR MAINLY EAST AND SOUTH OF TUCSON THIS WEEKEND. EXPECT GREATER COVERAGE OF THUNDERSTORMS BY TUESDAY FOLLOWED BY ANOTHER REDUCTION OF THUNDERSTORM ACTIVITY LATE NEXT WEEK. ABOVE NORMAL DAYTIME TEMPERATURES WILL PREVAIL INTO THE UPCOMING WEEK. && .DISCUSSION...SCATTERED SHOWERS AND THUNDERSTORMS WERE OCCURRING AT THIS TIME MOSTLY FROM ERN SANTA CRUZ COUNTY EWD ACROSS SRN COCHISE COUNTY TO THE NEW MEXICO BORDER. OTHER ISOLATED TO SCATTERED SHOWERS WERE FROM THE TUCSON METRO AREA NWD INTO SOUTH CENTRAL/SERN PINAL COUNTY. CLOUD TOPS WERE GENERALLY COOLING DURING THE PAST 1-2 HOURS ACROSS COCHISE/SANTA CRUZ COUNTIES EAST-TO-SOUTH OF TUCSON. OTHERWISE...MOSTLY CLOUDY SKIES WERE ACROSS THE AREA EXCEPT ACROSS WRN PIMA COUNTY WHERE CLEAR SKIES PREVAILED. DEWPOINTS AT LOWER ELEVATIONS VALID 04Z WERE MAINLY IN THE 60S...AND THESE TEMPS WERE NEARLY 5-10 DEGS F HIGHER VERSUS 24 HOURS AGO. 08/00Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS 1.67 INCH...WITH MLCAPE OF 412 J/KG. 08/00Z NAM/GFS...08/03Z RAP13 AND 08/03Z HRRR DEPICT ONLY A VERY GRADUAL REDUCTION IN THE COVERAGE OF SHOWERS/TSTMS THE REST OF TONIGHT INTO EARLY SAT MORNING. THESE MODELS FAVOR ERN PIMA COUNTY...ERN SANTA CRUZ COUNTY AND WRN COCHISE COUNTY WITH THE GREATEST POTENTIAL FOR ADDITIONAL SHOWERS/TSTMS. THUS...FOR THE REST OF TONIGHT INTO EARLY SAT MORNING...HAVE CONTINUED WITH ISOLATED TO SCATTERED SHOWERS/TSTMS FROM TUCSON EWD/ SWD TO THE NEW MEXICO/INTERNATIONAL BORDERS. PRECIP-FREE CONDITIONS SHOULD CONTINUE ACROSS WRN PIMA COUNTY...SOUTH CENTRAL PINAL COUNTY AND THE TOHONO O`ODHAM NATION. LOCALLY HEAVY RAINFALL SHOULD OCCUR WITH THE STRONGER SHOWERS/TSTMS. PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL. && .AVIATION...VALID THRU 09/06Z. ISOLATED TO SCATTERED -TSRA/-SHRA WILL OCCUR FROM KTUS VICINITY EAST AND SOUTH INTO SATURDAY MORNING. SCATTERED TO PERHAPS NUMEROUS -TSRA/-SHRA WILL THEN OCCUR MAINLY EAST OF KTUS SATURDAY AFTERNOON AND EVENING. EXPECT MVFR CONDITIONS AND BRIEF WIND GUSTS OF 35-45 KTS WITH THE STRONGER TSRA. OTHERWISE...CLEAR SKIES OR MOSTLY CLEAR SKIES WILL PREVAIL ACROSS WESTERN PIMA COUNTY WEST OF KTUS. ELSEWHERE...CLOUD DECKS WILL GENERALLY RANGE FROM 7-12K FT AGL. SURFACE WIND WILL MAINLY BE LESS THAN 10 KTS APART FROM TSRA GUSTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS MAINLY EAST AND SOUTH OF TUCSON THROUGH MONDAY. SCATTERED THUNDERSTORMS WILL THEN OCCUR ACROSS MUCH OF SOUTHEAST ARIZONA TUESDAY INTO WEDNESDAY. ANOTHER DRYING TREND IS ON TAP DURING THE LATTER PART OF NEXT WEEK. HOWEVER...THERE WILL BE ENOUGH MOISTURE FOR ISOLATED TO SCATTERED THUNDERSTORMS FAVORING THE WHITE MOUNTAINS AND LOCATIONS SOUTH OF TUCSON THURSDAY AND FRIDAY. && .PREV DISCUSSION /206 PM MST/...SYNOPTICALLY SPEAKING...AN UPPER LEVEL LOW PRESSURE CENTER IS TRACKING ACROSS NORTHERN CALIFORNIA AND THE GREAT BASIN. THE JET DYNAMICS ASSOCIATED WITH THE LOW ARE SPREADING ACROSS THE STATE HELPING TO ENHANCE THE CHANCE FOR CONTINUED STORMS INTO THE EVENING. HEAVY RAINFALL...FREQUENT LIGHTNING...SMALL HAIL...AND STRONG WIND GUSTS WILL ALL BE THREATS WITH THE STORMS. THE AREA OF LOW PRESSURE TO OUR NORTH IS EXPECTED TO TRACK EASTWARD OVER THE NEXT 48 HOURS. IT IS ANTICIPATED THAT THE LOW WILL ACT TO SHIFT THE DEEP MOISTURE EAST OF THE AREA FOR MUCH OF THE WEEKEND. ALTHOUGH THE DEEPEST MOISTURE WILL MOVE EASTWARD OVER NEW MEXICO AND SW TEXAS...ENOUGH WILL LINGER FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND NEAR THE NEW MEXICO BORDER BOTH SATURDAY AND SUNDAY AFTERNOON. ANOTHER SURGE OF MOISTURE WILL BE POSSIBLE ACROSS ALL OF SOUTHEAST ARIZONA MONDAY AND TUESDAY AS HIGH PRESSURE REBOUNDS WESTWARD INTO NM AND CO. MID RANGE MODELS ARE IN GOOD AGREEMENT THAT THE NEXT MONSOON SURGE WILL BE FOCUSED ON MONDAY/TUESDAY WITH UPPER LEVEL RIDGING SUPPRESSING WIDESPREAD CONVECTION BEGINNING EARLY WEDNESDAY AND LINGERING INTO LATE WEEK. ALONG WITH A REDUCTION IN STORM COVERAGE DURING THIS PERIOD...TEMPERATURES WILL LIKELY HAVE A CHANCE TO WARM TO ABOVE NORMAL READINGS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS PREVIOUS DISCUSSION...CANTIN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
915 PM MST FRI AUG 7 2015 .SYNOPSIS...ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR MAINLY EAST AND SOUTH OF TUCSON INTO EARLY NEXT WEEK. EXPECT GREATER COVERAGE OF THUNDERSTORMS TUESDAY INTO WEDNESDAY FOLLOWED BY REDUCED ACTIVITY LATE NEXT WEEK. ABOVE NORMAL DAYTIME TEMPERATURES WILL PREVAIL INTO THE UPCOMING WEEK. && .DISCUSSION...SCATTERED SHOWERS AND THUNDERSTORMS WERE OCCURRING AT THIS TIME MOSTLY FROM ERN SANTA CRUZ COUNTY EWD ACROSS SRN COCHISE COUNTY TO THE NEW MEXICO BORDER. OTHER ISOLATED TO SCATTERED SHOWERS WERE FROM THE TUCSON METRO AREA NWD INTO SOUTH CENTRAL/SERN PINAL COUNTY. CLOUD TOPS WERE GENERALLY COOLING DURING THE PAST 1-2 HOURS ACROSS COCHISE/SANTA CRUZ COUNTIES EAST-TO-SOUTH OF TUCSON. OTHERWISE...MOSTLY CLOUDY SKIES WERE ACROSS THE AREA EXCEPT ACROSS WRN PIMA COUNTY WHERE CLEAR SKIES PREVAILED. DEWPOINTS AT LOWER ELEVATIONS VALID 04Z WERE MAINLY IN THE 60S...AND THESE TEMPS WERE NEARLY 5-10 DEGS F HIGHER VERSUS 24 HOURS AGO. 08/00Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS 1.67 INCH...WITH MLCAPE OF 412 J/KG. 08/00Z NAM/GFS...08/03Z RAP13 AND 08/03Z HRRR DEPICT ONLY A VERY GRADUAL REDUCTION IN THE COVERAGE OF SHOWERS/TSTMS THE REST OF TONIGHT INTO EARLY SAT MORNING. THESE MODELS FAVOR ERN PIMA COUNTY...ERN SANTA CRUZ COUNTY AND WRN COCHISE COUNTY WITH THE GREATEST POTENTIAL FOR ADDITIONAL SHOWERS/TSTMS. THUS...FOR THE REST OF TONIGHT INTO EARLY SAT MORNING...HAVE CONTINUED WITH ISOLATED TO SCATTERED SHOWERS/TSTMS FROM TUCSON EWD/ SWD TO THE NEW MEXICO/INTERNATIONAL BORDERS. PRECIP-FREE CONDITIONS SHOULD CONTINUE ACROSS WRN PIMA COUNTY...SOUTH CENTRAL PINAL COUNTY AND THE TOHONO O`ODHAM NATION. LOCALLY HEAVY RAINFALL SHOULD OCCUR WITH THE STRONGER SHOWERS/TSTMS. PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL. && .AVIATION...VALID THRU 09/06Z. ISOLATED TO SCATTERED -TSRA/-SHRA WILL OCCUR FROM KTUS VICINITY EAST AND SOUTH INTO SATURDAY MORNING. SCATTERED TO PERHAPS NUMEROUS -TSRA/-SHRA WILL THEN OCCUR MAINLY EAST OF KTUS SATURDAY AFTERNOON AND EVENING. EXPECT MVFR CONDITIONS AND BRIEF WIND GUSTS OF 35-45 KTS WITH THE STRONGER TSRA. OTHERWISE...CLEAR SKIES OR MOSTLY CLEAR SKIES WILL PREVAIL ACROSS WESTERN PIMA COUNTY WEST OF KTUS. ELSEWHERE...CLOUD DECKS WILL GENERALLY RANGE FROM 7-12K FT AGL. SURFACE WIND WILL MAINLY BE LESS THAN 10 KTS APART FROM TSRA GUSTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS MAINLY EAST AND SOUTH OF TUCSON THROUGH MONDAY. SCATTERED THUNDERSTORMS WILL THEN OCCUR ACROSS MUCH OF SOUTHEAST ARIZONA TUESDAY INTO WEDNESDAY. ANOTHER DRYING TREND IS ON TAP DURING THE LATTER PART OF NEXT WEEK. HOWEVER...THERE WILL BE ENOUGH MOISTURE FOR ISOLATED TO SCATTERED THUNDERSTORMS FAVORING THE WHITE MOUNTAINS AND LOCATIONS SOUTH OF TUCSON THURSDAY AND FRIDAY. && .PREV DISCUSSION /206 PM MST/...SYNOPTICALLY SPEAKING...AN UPPER LEVEL LOW PRESSURE CENTER IS TRACKING ACROSS NORTHERN CALIFORNIA AND THE GREAT BASIN. THE JET DYNAMICS ASSOCIATED WITH THE LOW ARE SPREADING ACROSS THE STATE HELPING TO ENHANCE THE CHANCE FOR CONTINUED STORMS INTO THE EVENING. HEAVY RAINFALL...FREQUENT LIGHTNING...SMALL HAIL...AND STRONG WIND GUSTS WILL ALL BE THREATS WITH THE STORMS. THE AREA OF LOW PRESSURE TO OUR NORTH IS EXPECTED TO TRACK EASTWARD OVER THE NEXT 48 HOURS. IT IS ANTICIPATED THAT THE LOW WILL ACT TO SHIFT THE DEEP MOISTURE EAST OF THE AREA FOR MUCH OF THE WEEKEND. ALTHOUGH THE DEEPEST MOISTURE WILL MOVE EASTWARD OVER NEW MEXICO AND SW TEXAS...ENOUGH WILL LINGER FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND NEAR THE NEW MEXICO BORDER BOTH SATURDAY AND SUNDAY AFTERNOON. ANOTHER SURGE OF MOISTURE WILL BE POSSIBLE ACROSS ALL OF SOUTHEAST ARIZONA BY TUESDAY AS HIGH PRESSURE REBOUNDS WESTWARD INTO NM AND CO. MID RANGE MODELS ARE IN GOOD AGREEMENT THAT THE NEXT MONSOON SURGE WILL BE FOCUSED ON TUESDAY AND WEDNESDAY WITH UPPER LEVEL RIDGING SUPPRESSING WIDESPREAD CONVECTION BEGINNING EARLY THURSDAY AND LINGERING INTO LATE WEEK. ALONG WITH A REDUCTION IN STORM COVERAGE DURING THIS PERIOD...TEMPERATURES WILL LIKELY HAVE A CHANCE TO WARM TO ABOVE NORMAL READINGS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS PREVIOUS DISCUSSION...CANTIN
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
551 PM MDT SUN AUG 9 2015 .SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT) ISSUED AT 302 PM MDT SUN AUG 9 2015 SIGNIFICANTLY DRIER AIR WILL REMAIN OVER THE AREA OVERNIGHT. THE 12Z KGJT SOUNDING HAD PRECIPITABLE WATER OF 0.63 IN. DEWPOINTS WILL CONTINUE TO DROP INTO THE 40S AND EVEN UPPER 30S AT SOME LOCATIONS. CAPE VALUES ARE PROJECTED IN THE RAP13 AND HRRR TO REMAIN LOW AS WELL...SO CONVECTION EARLY THIS EVENING WILL BE WEAK AND ONLY OVER AND DOWNWIND OF RIDGES. ONLY LIGHT PRECIPITATION IS EXPECTED WITH THESE STORMS ALONG WITH GUSTY WINDS. THUNDERSTORMS SHOULD DISSIPATE WELL BEFORE MIDNIGHT WITH NEARLY CLEAR SKIES EXPECTED AGAIN OVERNIGHT. MOISTURE BEGINS TO INCREASE FROM THE SOUTH AGAIN ON MONDAY...SO EXPECTING SCATTERED ACTIVITY IN THE SAN JUANS MONDAY EVENING AS THE 12Z NAM AND GFS INDICATE A H5 VORTICITY MAX REACHING THE FOUR CORNERS MONDAY EVENING. THE EURO IS A BIT SLOWER WITH THIS ENERGY...BUT IN ANY CASE IT DOES LOOK LIKE SHOWERS AND ISO TSTORMS WILL CONTINUE THROUGH THE OVERNIGHT HOURS ON MONDAY NIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 302 PM MDT SUN AUG 9 2015 TUESDAY MORNING WILL BE A MUGGY ONE...WITH CLOUD COVER AND RAIN SHOWERS ACROSS MUCH OF THE REGION BY MIDDAY. MONSOONAL MOISTURE WILL BE AT ITS HIGHEST THIS WEEK ON TUESDAY AFTERNOON AS PRECIPITABLE WATER VALUES ACROSS THE FOUR CORNERS REACH UPWARDS OF 1.2 INCHES AND MORE THAN 0.75 INCHES REACHING THE UT/CO/WY BORDER. THOUGH DEEP MOISTURE WILL BE IN PLACE...NOT FEELING VERY CONFIDENT ON THE THREAT OF FLASH FLOODING SINCE WE WILL LIKELY BE DEALING WITH WIDESPREAD CLOUD COVER AGAIN AND LACK OF LIFTING DUE TO DAYTIME HEATING. LOCALIZED FLASH FLOODING COULD OCCUR IF THERE IS SOME CLEARING WHICH PRODUCES ENOUGH LIFT FOR MORE VERTICALLY SUPPORTED THUNDERSTORMS. WEDNESDAY WILL LIKELY BE MORE OF A THREAT DAY FOR FLASH FLOODING WITH SKY CONDITIONS LESS CLOUDY BUT WITH DEEP MOISTURE STILL IN PLACE. FORECAST CONVECTIVE INDICES ON THE NAM ARE MORE FAVORABLE FOR HEAVY RAIN PRODUCING THUNDERSTORMS ON WEDNESDAY THAN TUESDAY...SO THESE DAYS WILL NEED TO BE WATCHED FOR POTENTIAL IMPACTS. THE LACK OF JET SUPPORT WILL KEEP STEERING WINDS LIGHT THROUGH THE END OF THE WEEK SO ANY SHOWERS AND STORMS WHICH DEVELOP WILL MOVE SLOWLY. SOME DRYING OCCURS LATER IN THE WORK WEEK DUE TO HIGH PRESSURE AMPLIFYING OVER THE ROCKIES...BUT PRECIPITABLE WATER VALUES REMAIN NEAR THREE QUARTERS OF AN INCH SO DIURNALLY INDUCED SHOWERS AND THUNDERSTORMS WILL DEVELOP EVERYDAY OVER HIGHER TERRAIN. NEXT SATURDAY...A TROUGH OVER THE PACIFIC NORTHWEST IS PROGGED TO MOVE INLAND NORTH OF COLORADO. THE INTERACTION OF THIS TROUGH WITH THE HIGH PRESSURE IN PLACE OVER THE ROCKIES WILL DRIVE A 50 KT JET INTO NE UTAH AND NW COLORADO AND POTENTIALLY CREATE MORE CONVECTIVE ACTIVITY UP NORTH NEXT WEEKEND. BUMPED HIGH TEMPS UP A COUPLE OF DEGREES IN THE LOWER VALLEYS TOWARD THE END OF THE WEEK CLOSER TO MOS GUIDANCE FOR A MIDDLE GROUND SOLUTION. FEEL THAT MOS GUIDANCE IS TOO HOT BUT PREVIOUS FORECAST WAS TOO LOW CONSIDERING THE EXPECTED AMOUNT OF SUNSHINE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 551 PM MDT SUN AUG 9 2015 LOW CLOUD TOP CONVECTION THROUGH 02Z THIS EVENING WITH LOCAL SPRINKLES OR -TSRA WITH OUTFLOW 25KT WIND. CLEARING OVERNIGHT BUT MOISTURE SURGE FROM THE SOUTH ON MONDAY BRING A BETTER CHANCE FOR -SHRA/-TSRA...ESPECIALLY OVER SW COLORADO AND THE CENTRAL COLORADO MOUNTAINS. ISOLATED +TSRA WITH CIGS OBSCURING MOUNTAIN TOPS FROM THE STRONGEST CELLS MONDAY AFTERNOON. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...CC/JAM LONG TERM...JAM AVIATION...PF
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1125 AM MDT SAT AUG 8 2015 .UPDATE... ISSUED AT 956 AM MDT SAT AUG 8 2015 ADJUSTED POPS TO REFLECT LATEST HIGH RES MODEL GUIDANCE RUNS THIS MORNING. LATEST GUIDANCE IN GOOD AGREEMENT FOR SCATTERED SHOWERS AND THUNDERSTORMS OVER THE PALMER DIVIDE AND FAR SE CO THIS AFTERNOON...INCLUDING BACA...BENT...PROWERS...AND KIOWA COUNTIES. FAR SE CO MAY SEE A FEW STRONG TO SEVERE STORMS LATE THIS AFTERNOON...AS 30-35 KNOTS OF 0-6 KM BULK SHEAR WILL BE PRESENT WITH 1000-1500 J/KG OF CAPE AVAILABLE. UPPER LEVEL DISTURBANCES WITHIN THE MONSOON PLUME WILL HELP TO INITIATE CONVECTION...BUT THE LIMITING FACTOR COULD BE CAPE...WITH NAM AND HRRR SHOWING DEW POINTS ONLY IN THE UPPER 40S TO LOW 50S ACROSS THE I-25 CORRIDOR WITH VALUES SLIGHTLY HIGHER TOWARDS FAR SE CO. LUKINBEAL && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 500 AM MDT SAT AUG 8 2015 ...ANOTHER ROUND OF THUNDERSTORMS TODAY...A FEW STRONG ACROSS THE SOUTHEAST PLAINS... MONSOON PLUME EXTENDS ACROSS CO WITH A COUPLE OF EMBEDDED WAVES MOVING THROUGH SOUTHWEST FLOW ALOFT. THE FIRST IS MOVING ACROSS THE SE MTS INTO THE ADJACENT PLAINS EARLY THIS MORNING. THIS WAVE IS PRETTY WEAK...BUT IS ENHANCING SOME MID/HIGH CLOUD DECK OVER THE EASTERN PORTIONS OF THE AREA...WITH SOME SPOTTY SHOWERS ACROSS THE PLAINS AT TIMES. THIS WAVE SHOULD LIFT OFF TO THE NORTHEAST THROUGH THE MORNING. MEANWHILE...SHOWERS WILL CONTINUE ALONG THE CONTDVD AS THE NEXT WAVE ACROSS NW AZ LIFTS UP INTO THE 4 CORNERS REGION THIS MORNING. THIS WAVE WILL MOVE ACROSS THE REMAINDER OF CO DURING THE AFTERNOON. ACROSS THE PLAINS...SFC LOW IS POSITIONED ACROSS FAR SOUTHEAST CO...WITH WEST TO NORTHWEST WINDS ALONG THE I-25 CORRIDOR AND SOUTHERN PORTIONS OF THE SOUTHEAST PLAINS. MODELS SUGGEST A WEAK NORTHERLY SURGE WILL WRAP AROUND THE NORTH SIDE OF THE SFC LOW INTO THE SE PLAINS...WHICH WILL INCREASE DEW POINTS AGAIN FROM THE LOWER TO MID 50S...TO MID-UPPER 50S NEAR THE BORDER BY AFTERNOON. WINDS DON`T LOOK VERY STRONG ACROSS THE PLAINS...BUT THERE SHOULD BE SOME CONVERGENCE ALONG THIS BOUNDARY WHICH SETS UP ACROSS SOUTHEAST PLAINS. DEEP LAYER SHEAR LOOKS A LITTLE STRONGER TODAY...BUT CAPES LOOK LOWER THAN YESTERDAY. EACH SUCCESSIVE RUN OF THE HRRR SEEMS TO BE TRENDING THE DEW POINTS DOWNWARD ACROSS SE CO WITH HIGHER DEW POINTS AND CAPES ACROSS SOUTHWEST KANSAS. WILL HAVE TO WATCH TRENDS IN THE LATEST HIGH RES MODELS AND OBSERVATIONS TODAY TO HONE DOWN THESE DETAILS. CERTAINLY ENOUGH MOISTURE WILL BE PRESENT FOR AT LEAST ISOLATED TO SCATTERED THUNDERSTORMS. MAIN THREAT WILL BE LOCALLY HEAVY RAINFALL...WHICH COULD OCCUR JUST ABOUT ANYWHERE. DEPENDING ON THE POSITION OF THE BOUNDARY AND AMOUNT OF DEW POINT RETURN...COULD SEE AN ISOLATED STRONG TO SEVERE THUNDERSTORM ACROSS THE SOUTHEAST COUNTIES...NAMELY KIOWA...BENT...PROWERS...AND BACA COUNTIES. LARGE HAIL AND DAMAGING WINDS WOULD BE THE PRIMARY STORM THREATS. THUNDERSTORMS SHOULD DIMINISH FROM WEST TO EAST TONIGHT WITH MORE DRYING EXPECTED TO SPREAD IN FROM THE WEST AS THE MONSOON PLUME SHIFTS EASTWARD. THIS SHOULD RESULT IN COOLER LOWS TONIGHT THAN THIS MORNING ACROSS THE WESTERN MOUNTAIN VALLEYS. MEANWHILE...MODELS SPREAD HIGHER DEW POINTS BACK INTO THE SE PLAINS...AND MAY HAVE SOME STRATUS DEVELOP ACROSS PORTIONS OF THE FAR SOUTHEAST PLAINS TOWARDS MORNING. -KT .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 500 AM MDT SAT AUG 8 2015 NOT MANY ADJUSTMENTS REQUIRED DURING THE LONGER TERM WITH RELATIVELY ACTIVE METEOROLOGICAL CONDITIONS ANTICIPATED. PRIMARY METEOROLOGICAL ISSUES CONTINUE TO BE TEMPERATURES...POPS AND THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AND STRONGER STORMS AT TIMES. LATEST PV ANALYSIS...COMPUTER SIMULATIONS AND FORECAST MODEL SOUNDINGS STILL SUGGEST THAT UPPER HIGH CENTERED OVER NORTHEASTERN TEXAS AT 12Z SUNDAY WILL BEGIN PROGRESSING WEST AND BECOME CENTERED OVER THE TEXAS PANHANDLE REGION BY TUESDAY. UPPER RIDGE IS STILL PROJECTED TO BECOME CENTERED OVER THE NORTHERN NEW MEXICO/COLORADO REGION FROM LATER WEDNESDAY INTO FRIDAY. DEEPEST ATMOSPHERIC MOISTURE PROFILES DURING THE LONGER TERM ARE STILL PROJECTED FROM SUNDAY INTO TUESDAY NIGHT. THE MOIST ATMOSPHERIC PROFILE WILL INTERACT WITH FAVORABLE LOW-LEVEL WIND FLOW...THE DAILY OROGRAPHIC CYCLE AND UPPER DISTURBANCES AT TIMES TO PRODUCE GENERALLY SCATTERED SHOWER AND THUNDERSTORM ACTIVITY INTO AT LEAST TUESDAY NIGHT WITH SLIGHTLY DECREASED POPS THEN EXPECTED BY LATER IN THE WEEK. PER PREVIOUS DISCUSSIONS...ESPECIALLY DURING THE SUNDAY INTO TUESDAY NIGHT TIME-FRAME...THE PROJECTED HIGHER PRECIPITABLE WATER VALUES ARE EXPECTED TO GENERATE LOCALLY HEAVY RAINFALL CAPABLE OF PRODUCING LOCALIZED FLASH FLOODING AT TIMES...ESPECIALLY IF THE HEAVY RAINFALL IMPACTS RECENT BURN SCARS. ALSO...STRONGER STORMS AT TIMES ARE ALSO ANTICIPATED DUE TO SOMEWHAT ELEVATED CAPE...LI AND BULK SHEAR VALUES. ALSO...GENERALLY ABOVE CLIMATOLOGICAL EARLY TO MID AUGUST TEMPERATURES ARE STILL PROJECTED DURING THE MAJORITY OF THE LONGER TERM WITH MONDAY AND TUESDAY HAVING THE HIGHEST POTENTIAL OF EXPERIENCING BELOW SEASONAL TEMPERATURES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1122 AM MDT SAT AUG 8 2015 VFR CONDITIONS EXPECTED AT THE TAF SITES THROUGH THE AFTERNOON AND EARLY EVENING...WITH BRIEF MVFR CIGS/VIS POSSIBLE UNDER STRONGER THUNDERSTORMS. SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS...PALMER DIVIDE...AND RATON MESA THIS AFTERNOON BEFORE SPREADING ACROSS THE EASTERN PLAINS. ALL THREE TAF SITES COULD SEE VCTS AFTER 21-22Z WITH GUSTY OUTFLOW WINDS BEING THE PRIMARY CONCERN. OVERNIGHT LASTEST MODEL GUIDANCE IS SUGGESTING A STRATUS DECK DEVELOPING ACROSS THE EASTERN PLAINS AS OUTFLOW BOUNDARIES FROM WESTERN KS AND SE UPSLOPE FLOW PUSH MOIST LOW LEVEL MOISTURE INTO THE I-25 CORRIDOR. STARTING AROUND 08Z...KCOS AND KPUB WILL LIKELY BE IMPACTED BY THE STRATUS DECK WITH MVFR TO BRIEF IFR CONDITIONS POSSIBLE OVERNIGHT INTO EARLY TOMORROW MORNING DUE TO CIGS...WITH STRATUS EXPECTED TO CLEAR OUT BY 15Z AS WINDS SHIFT TO A N/NE COMPONENT AT KCOS AND KPUB. LUKINBEAL && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AL/HODANISH AVIATION...AL/HODANISH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1013 AM MDT SAT AUG 8 2015 .UPDATE... ISSUED AT 956 AM MDT SAT AUG 8 2015 ADJUSTED POPS TO REFLECT LATEST HIGH RES MODEL GUIDANCE RUNS THIS MORNING. LATEST GUIDANCE IN GOOD AGREEMENT FOR SCATTERED SHOWERS AND THUNDERSTORMS OVER THE PALMER DIVIDE AND FAR SE CO THIS AFTERNOON...INCLUDING BACA...BENT...PROWERS...AND KIOWA COUNTIES. FAR SE CO MAY SEE A FEW STRONG TO SEVERE STORMS LATE THIS AFTERNOON...AS 30-35 KNOTS OF 0-6 KM BULK SHEAR WILL BE PRESENT WITH 1000-1500 J/KG OF CAPE AVAILABLE. UPPER LEVEL DISTURBANCES WITHIN THE MONSOON PLUME WILL HELP TO INITIATE CONVECTION...BUT THE LIMITING FACTOR COULD BE CAPE...WITH NAM AND HRRR SHOWING DEW POINTS ONLY IN THE UPPER 40S TO LOW 50S ACROSS THE I-25 CORRIDOR WITH VALUES SLIGHTLY HIGHER TOWARDS FAR SE CO. LUKINBEAL && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 500 AM MDT SAT AUG 8 2015 ...ANOTHER ROUND OF THUNDERSTORMS TODAY...A FEW STRONG ACROSS THE SOUTHEAST PLAINS... MONSOON PLUME EXTENDS ACROSS CO WITH A COUPLE OF EMBEDDED WAVES MOVING THROUGH SOUTHWEST FLOW ALOFT. THE FIRST IS MOVING ACROSS THE SE MTS INTO THE ADJACENT PLAINS EARLY THIS MORNING. THIS WAVE IS PRETTY WEAK...BUT IS ENHANCING SOME MID/HIGH CLOUD DECK OVER THE EASTERN PORTIONS OF THE AREA...WITH SOME SPOTTY SHOWERS ACROSS THE PLAINS AT TIMES. THIS WAVE SHOULD LIFT OFF TO THE NORTHEAST THROUGH THE MORNING. MEANWHILE...SHOWERS WILL CONTINUE ALONG THE CONTDVD AS THE NEXT WAVE ACROSS NW AZ LIFTS UP INTO THE 4 CORNERS REGION THIS MORNING. THIS WAVE WILL MOVE ACROSS THE REMAINDER OF CO DURING THE AFTERNOON. ACROSS THE PLAINS...SFC LOW IS POSITIONED ACROSS FAR SOUTHEAST CO...WITH WEST TO NORTHWEST WINDS ALONG THE I-25 CORRIDOR AND SOUTHERN PORTIONS OF THE SOUTHEAST PLAINS. MODELS SUGGEST A WEAK NORTHERLY SURGE WILL WRAP AROUND THE NORTH SIDE OF THE SFC LOW INTO THE SE PLAINS...WHICH WILL INCREASE DEW POINTS AGAIN FROM THE LOWER TO MID 50S...TO MID-UPPER 50S NEAR THE BORDER BY AFTERNOON. WINDS DON`T LOOK VERY STRONG ACROSS THE PLAINS...BUT THERE SHOULD BE SOME CONVERGENCE ALONG THIS BOUNDARY WHICH SETS UP ACROSS SOUTHEAST PLAINS. DEEP LAYER SHEAR LOOKS A LITTLE STRONGER TODAY...BUT CAPES LOOK LOWER THAN YESTERDAY. EACH SUCCESSIVE RUN OF THE HRRR SEEMS TO BE TRENDING THE DEW POINTS DOWNWARD ACROSS SE CO WITH HIGHER DEW POINTS AND CAPES ACROSS SOUTHWEST KANSAS. WILL HAVE TO WATCH TRENDS IN THE LATEST HIGH RES MODELS AND OBSERVATIONS TODAY TO HONE DOWN THESE DETAILS. CERTAINLY ENOUGH MOISTURE WILL BE PRESENT FOR AT LEAST ISOLATED TO SCATTERED THUNDERSTORMS. MAIN THREAT WILL BE LOCALLY HEAVY RAINFALL...WHICH COULD OCCUR JUST ABOUT ANYWHERE. DEPENDING ON THE POSITION OF THE BOUNDARY AND AMOUNT OF DEW POINT RETURN...COULD SEE AN ISOLATED STRONG TO SEVERE THUNDERSTORM ACROSS THE SOUTHEAST COUNTIES...NAMELY KIOWA...BENT...PROWERS...AND BACA COUNTIES. LARGE HAIL AND DAMAGING WINDS WOULD BE THE PRIMARY STORM THREATS. THUNDERSTORMS SHOULD DIMINISH FROM WEST TO EAST TONIGHT WITH MORE DRYING EXPECTED TO SPREAD IN FROM THE WEST AS THE MONSOON PLUME SHIFTS EASTWARD. THIS SHOULD RESULT IN COOLER LOWS TONIGHT THAN THIS MORNING ACROSS THE WESTERN MOUNTAIN VALLEYS. MEANWHILE...MODELS SPREAD HIGHER DEW POINTS BACK INTO THE SE PLAINS...AND MAY HAVE SOME STRATUS DEVELOP ACROSS PORTIONS OF THE FAR SOUTHEAST PLAINS TOWARDS MORNING. -KT .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 500 AM MDT SAT AUG 8 2015 NOT MANY ADJUSTMENTS REQUIRED DURING THE LONGER TERM WITH RELATIVELY ACTIVE METEOROLOGICAL CONDITIONS ANTICIPATED. PRIMARY METEOROLOGICAL ISSUES CONTINUE TO BE TEMPERATURES...POPS AND THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AND STRONGER STORMS AT TIMES. LATEST PV ANALYSIS...COMPUTER SIMULATIONS AND FORECAST MODEL SOUNDINGS STILL SUGGEST THAT UPPER HIGH CENTERED OVER NORTHEASTERN TEXAS AT 12Z SUNDAY WILL BEGIN PROGRESSING WEST AND BECOME CENTERED OVER THE TEXAS PANHANDLE REGION BY TUESDAY. UPPER RIDGE IS STILL PROJECTED TO BECOME CENTERED OVER THE NORTHERN NEW MEXICO/COLORADO REGION FROM LATER WEDNESDAY INTO FRIDAY. DEEPEST ATMOSPHERIC MOISTURE PROFILES DURING THE LONGER TERM ARE STILL PROJECTED FROM SUNDAY INTO TUESDAY NIGHT. THE MOIST ATMOSPHERIC PROFILE WILL INTERACT WITH FAVORABLE LOW-LEVEL WIND FLOW...THE DAILY OROGRAPHIC CYCLE AND UPPER DISTURBANCES AT TIMES TO PRODUCE GENERALLY SCATTERED SHOWER AND THUNDERSTORM ACTIVITY INTO AT LEAST TUESDAY NIGHT WITH SLIGHTLY DECREASED POPS THEN EXPECTED BY LATER IN THE WEEK. PER PREVIOUS DISCUSSIONS...ESPECIALLY DURING THE SUNDAY INTO TUESDAY NIGHT TIME-FRAME...THE PROJECTED HIGHER PRECIPITABLE WATER VALUES ARE EXPECTED TO GENERATE LOCALLY HEAVY RAINFALL CAPABLE OF PRODUCING LOCALIZED FLASH FLOODING AT TIMES...ESPECIALLY IF THE HEAVY RAINFALL IMPACTS RECENT BURN SCARS. ALSO...STRONGER STORMS AT TIMES ARE ALSO ANTICIPATED DUE TO SOMEWHAT ELEVATED CAPE...LI AND BULK SHEAR VALUES. ALSO...GENERALLY ABOVE CLIMATOLOGICAL EARLY TO MID AUGUST TEMPERATURES ARE STILL PROJECTED DURING THE MAJORITY OF THE LONGER TERM WITH MONDAY AND TUESDAY HAVING THE HIGHEST POTENTIAL OF EXPERIENCING BELOW SEASONAL TEMPERATURES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 500 AM MDT SAT AUG 8 2015 VFR CONDITIONS EXPECT THIS MORNING AT THE TAF SITES...THOUGH WILL HAVE TO WATCH KALS CLOSELY AS T/TD SPREADS ARE CLOSE. FOR NOW THINK EXTENSIVE MID AND HIGH CLOUD COVER SHOULD PREVENT ANY PATCHY GROUND FOG DEVELOPMENT. THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS...AND PALMER AND RATON MESA REGIONS BY AFTERNOON. AS THESE THUNDERSTORMS SPREAD EASTWARD ACROSS THE LOWER ELEVATIONS...ALL THREE TAF SITES COULD SEE VCTS AFTER 20-21Z. GUSTY ERRATIC WINDS...AND VFR TO BRIEF MVFR CIGS/VIS WILL BE POSSIBLE WITH THE STRONGER STORMS. THUNDERSTORMS SHOULD MOVE EASTWARD AND DIMINISH THIS EVENING...WITH CONDITIONS REMAINING VFR. COULD SEE SOME STRATUS DEVELOP ACROSS PORTIONS OF THE SOUTHEAST PLAINS SATURDAY NIGHT...BUT FOR NOW MOST LIKELY AREA APPEARS TO BE EAST OF THE I-25 CORRIDOR AND THE KCOS AND KPUB TERMINALS. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AL/HODANISH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
502 AM MDT SAT AUG 8 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 500 AM MDT SAT AUG 8 2015 ...ANOTHER ROUND OF THUNDERSTORMS TODAY...A FEW STRONG ACROSS THE SOUTHEAST PLAINS... MONSOON PLUME EXTENDS ACROSS CO WITH A COUPLE OF EMBEDDED WAVES MOVING THROUGH SOUTHWEST FLOW ALOFT. THE FIRST IS MOVING ACROSS THE SE MTS INTO THE ADJACENT PLAINS EARLY THIS MORNING. THIS WAVE IS PRETTY WEAK...BUT IS ENHANCING SOME MID/HIGH CLOUD DECK OVER THE EASTERN PORTIONS OF THE AREA...WITH SOME SPOTTY SHOWERS ACROSS THE PLAINS AT TIMES. THIS WAVE SHOULD LIFT OFF TO THE NORTHEAST THROUGH THE MORNING. MEANWHILE...SHOWERS WILL CONTINUE ALONG THE CONTDVD AS THE NEXT WAVE ACROSS NW AZ LIFTS UP INTO THE 4 CORNERS REGION THIS MORNING. THIS WAVE WILL MOVE ACROSS THE REMAINDER OF CO DURING THE AFTERNOON. ACROSS THE PLAINS...SFC LOW IS POSITIONED ACROSS FAR SOUTHEAST CO...WITH WEST TO NORTHWEST WINDS ALONG THE I-25 CORRIDOR AND SOUTHERN PORTIONS OF THE SOUTHEAST PLAINS. MODELS SUGGEST A WEAK NORTHERLY SURGE WILL WRAP AROUND THE NORTH SIDE OF THE SFC LOW INTO THE SE PLAINS...WHICH WILL INCREASE DEW POINTS AGAIN FROM THE LOWER TO MID 50S...TO MID-UPPER 50S NEAR THE BORDER BY AFTERNOON. WINDS DON`T LOOK VERY STRONG ACROSS THE PLAINS...BUT THERE SHOULD BE SOME CONVERGENCE ALONG THIS BOUNDARY WHICH SETS UP ACROSS SOUTHEAST PLAINS. DEEP LAYER SHEAR LOOKS A LITTLE STRONGER TODAY...BUT CAPES LOOK LOWER THAN YESTERDAY. EACH SUCCESSIVE RUN OF THE HRRR SEEMS TO BE TRENDING THE DEW POINTS DOWNWARD ACROSS SE CO WITH HIGHER DEW POINTS AND CAPES ACROSS SOUTHWEST KANSAS. WILL HAVE TO WATCH TRENDS IN THE LATEST HIGH RES MODELS AND OBSERVATIONS TODAY TO HONE DOWN THESE DETAILS. CERTAINLY ENOUGH MOISTURE WILL BE PRESENT FOR AT LEAST ISOLATED TO SCATTERED THUNDERSTORMS. MAIN THREAT WILL BE LOCALLY HEAVY RAINFALL...WHICH COULD OCCUR JUST ABOUT ANYWHERE. DEPENDING ON THE POSITION OF THE BOUNDARY AND AMOUNT OF DEW POINT RETURN...COULD SEE AN ISOLATED STRONG TO SEVERE THUNDERSTORM ACROSS THE SOUTHEAST COUNTIES...NAMELY KIOWA...BENT...PROWERS...AND BACA COUNTIES. LARGE HAIL AND DAMAGING WINDS WOULD BE THE PRIMARY STORM THREATS. THUNDERSTORMS SHOULD DIMINISH FROM WEST TO EAST TONIGHT WITH MORE DRYING EXPECTED TO SPREAD IN FROM THE WEST AS THE MONSOON PLUME SHIFTS EASTWARD. THIS SHOULD RESULT IN COOLER LOWS TONIGHT THAN THIS MORNING ACROSS THE WESTERN MOUNTAIN VALLEYS. MEANWHILE...MODELS SPREAD HIGHER DEW POINTS BACK INTO THE SE PLAINS...AND MAY HAVE SOME STRATUS DEVELOP ACROSS PORTIONS OF THE FAR SOUTHEAST PLAINS TOWARDS MORNING. -KT .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 500 AM MDT SAT AUG 8 2015 NOT MANY ADJUSTMENTS REQUIRED DURING THE LONGER TERM WITH RELATIVELY ACTIVE METEOROLOGICAL CONDITIONS ANTICIPATED. PRIMARY METEOROLOGICAL ISSUES CONTINUE TO BE TEMPERATURES...POPS AND THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AND STRONGER STORMS AT TIMES. LATEST PV ANALYSIS...COMPUTER SIMULATIONS AND FORECAST MODEL SOUNDINGS STILL SUGGEST THAT UPPER HIGH CENTERED OVER NORTHEASTERN TEXAS AT 12Z SUNDAY WILL BEGIN PROGRESSING WEST AND BECOME CENTERED OVER THE TEXAS PANHANDLE REGION BY TUESDAY. UPPER RIDGE IS STILL PROJECTED TO BECOME CENTERED OVER THE NORTHERN NEW MEXICO/COLORADO REGION FROM LATER WEDNESDAY INTO FRIDAY. DEEPEST ATMOSPHERIC MOISTURE PROFILES DURING THE LONGER TERM ARE STILL PROJECTED FROM SUNDAY INTO TUESDAY NIGHT. THE MOIST ATMOSPHERIC PROFILE WILL INTERACT WITH FAVORABLE LOW-LEVEL WIND FLOW...THE DAILY OROGRAPHIC CYCLE AND UPPER DISTURBANCES AT TIMES TO PRODUCE GENERALLY SCATTERED SHOWER AND THUNDERSTORM ACTIVITY INTO AT LEAST TUESDAY NIGHT WITH SLIGHTLY DECREASED POPS THEN EXPECTED BY LATER IN THE WEEK. PER PREVIOUS DISCUSSIONS...ESPECIALLY DURING THE SUNDAY INTO TUESDAY NIGHT TIME-FRAME...THE PROJECTED HIGHER PRECIPITABLE WATER VALUES ARE EXPECTED TO GENERATE LOCALLY HEAVY RAINFALL CAPABLE OF PRODUCING LOCALIZED FLASH FLOODING AT TIMES...ESPECIALLY IF THE HEAVY RAINFALL IMPACTS RECENT BURN SCARS. ALSO...STRONGER STORMS AT TIMES ARE ALSO ANTICIPATED DUE TO SOMEWHAT ELEVATED CAPE...LI AND BULK SHEAR VALUES. ALSO...GENERALLY ABOVE CLIMATOLOGICAL EARLY TO MID AUGUST TEMPERATURES ARE STILL PROJECTED DURING THE MAJORITY OF THE LONGER TERM WITH MONDAY AND TUESDAY HAVING THE HIGHEST POTENTIAL OF EXPERIENCING BELOW SEASONAL TEMPERATURES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 500 AM MDT SAT AUG 8 2015 VFR CONDITIONS EXPECT THIS MORNING AT THE TAF SITES...THOUGH WILL HAVE TO WATCH KALS CLOSELY AS T/TD SPREADS ARE CLOSE. FOR NOW THINK EXTENSIVE MID AND HIGH CLOUD COVER SHOULD PREVENT ANY PATCHY GROUND FOG DEVELOPMENT. THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS...AND PALMER AND RATON MESA REGIONS BY AFTERNOON. AS THESE THUNDERSTORMS SPREAD EASTWARD ACROSS THE LOWER ELEVATIONS...ALL THREE TAF SITES COULD SEE VCTS AFTER 20-21Z. GUSTY ERRATIC WINDS...AND VFR TO BRIEF MVFR CIGS/VIS WILL BE POSSIBLE WITH THE STRONGER STORMS. THUNDERSTORMS SHOULD MOVE EASTWARD AND DIMINISH THIS EVENING...WITH CONDITIONS REMAINING VFR. COULD SEE SOME STRATUS DEVELOP ACROSS PORTIONS OF THE SOUTHEAST PLAINS SATURDAY NIGHT...BUT FOR NOW MOST LIKELY AREA APPEARS TO BE EAST OF THE I-25 CORRIDOR AND THE KCOS AND KPUB TERMINALS. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
700 PM EDT SAT AUG 8 2015 .SYNOPSIS... HIGH PRESSURE WILL MAINTAIN DRY WEATHER THROUGH SUN AS LOW PRESSURE REMAINS WELL OFFSHORE...THOUGH A SPOT SHOWER IS POSSIBLE ACROSS THE INTERIOR SUN AFTERNOON. LOW PRESSURE WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS AT TIMES MON NIGHT INTO WED MORNING. A TREND TOWARD DRIER WEATHER IS LIKELY THROUGH THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 7 PM UPDATE...HIGH CIRRUS CLOUDS REMAIN IN PLACE ACROSS SOUTHERN NEW ENGLAND THIS EVENING. MADE SOME ADJUSTMENTS TO THE SKY COVER TO ACCOUNT FOR THE LATEST SATELLITE TRENDS. OTHERWISE...THE FORECAST IS ON TRACK. 315 PM UPDATE... PLENTY OF DIURNAL CU ACROSS INTERIOR WHERE HRRR AND 12Z NAM WANT TO BRING SOME ISOLATED SHOWER ACTIVITY THIS AFTERNOON. COLUMN IS FAIRLY DRY SO AM NOT BUYING INTO THAT...MODELS ARE MORE LIKELY INDICATING BUILDING CU WHICH IS EVIDENT ON SATELLITE NEAR BERKSHIRES. MEANWHILE COASTAL LOW IS THROWING BACK SOME PATCHY MID AND HIGH CLOUDS ALONG S COAST...CAPE COD AND ISLANDS. EXPECT THESE CLOUDS TO THICKEN UP TONIGHT BUT NO RAIN EXPECTED AS BEST LIFT STAYS OFFSHORE WITH PROGRESSIVE UPPER FLOW. SOME OF HIGH-RES MODELS /HRRR...RAP AND ARW-WRF/ WANT TO BRING RAINFALL TO SE NEW ENGLAND LATER TONIGHT BUT THAT LOOKS TO BE OVERDONE. ANOTHER PLEASANTLY COOL NIGHT AHEAD WITH GOOD RADIATIONAL COOLING CONDITIONS AWAY FROM INFLUENCE OF MID/HIGH CLOUDS NEAR S COAST. LEANED TOWARD COOLER GFS LAMP GUIDANCE WHICH BRINGS LOWS INTO UPPER 40S ACROSS NW MA AND MAINLY 50S ELSEWHERE. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... EXPECTING A GOOD AMOUNT OF CLOUDINESS NEAR CAPE COD AND ISLANDS SUN DUE TO INCREASING NE FLOW ON PERIPHERY OF COASTAL LOW. MODEL CROSS SECTIONS SHOW GOOD AMOUNT OF LOW LEVEL MOISTURE BELOW 950 MB WHICH SHOULD BECOME TRAPPED. NO REAL MECHANISM FOR RAINFALL SO DRY WEATHER ANTICIPATED AS DEEPER MOISTURE AND LIFT REMAIN WELL OFFSHORE. SOME QUESTION AS TO WHETHER OR NOT LOW CLOUDS WILL BREAK DURING AFTERNOON...BUT FOR NOW LEANED TOWARD THEM HANGING ON. ACROSS INTERIOR...MODELS CONTINUE TO HINT AT POSSIBILITY OF FEW SHOWERS BY AFTERNOON DUE TO SUBTLE LIFT FROM UPPER TROUGH. LOW LEVEL CONVERGENCE IS MINIMAL DUE TO WEAK WIND FIELDS...SO ANY ACTIVITY WOULD BE TIED TO TERRAIN. STABILITY PARAMETERS MARGINAL SO EXPECT AN ISOLATED SHOWER OR PERHAPS A THUNDERSTORM ACROSS NW AND POSSIBLY N CENTRAL MA. HIGHS SHOULD BE A LITTLE COOLER THAN TODAY...ESPECIALLY NEAR COAST DUE TO NE FLOW AND CLOUDINESS...RANGING FROM AROUND 70 ON OUTER CAPE TO AROUND 80 FARTHER INLAND. SUBSIDENCE AND SOME DRYING SUN NIGHT SHOULD LEAD TO AT LEAST PARTIAL CLEARING...BUT CONTINUED ONSHORE FLOW MAY KEEP CLOUDS LOCKED IN CLOSER TO COAST. LOWS SHOULD DROP BACK INTO 50S AND LOWER 60S. && .LONG TERM /MONDAY THROUGH SATURDAY/... HIGHLIGHTS... * UNSETTLED WEATHER LIKELY LATE MON NIGHT THROUGH WED MORNING * TEMPS SLIGHTLY BELOW NORMAL FOR MUCH OF THE WEEK * POSSIBLE RETURN TO AUGUST HEAT FOR SATURDAY OVERALL...MODELS ARE IN DECENT AGREEMENT THROUGH MUCH OF THE LONG TERM. THERE ARE A COUPLE OF DISCREPANCIES THAT CONTINUE THROUGH THE PERIOD. AS FAR AS SENSIBLE WEATHER GOES...THE MODELS ARE IN AGREEMENT. LOOKING AT AN UPPER LEVEL TROUGH IN THE GREAT LAKES MONDAY SLOWLY MOVING EASTWARD OVER THE NORTHEAST AND NEW ENGLAND BY WEDNESDAY AND POTENTIALLY STALLING THERE THROUGH THE END OF THE FORECAST PERIOD. THE ECMWF KEEPS THE PATTERN MORE AMPLIFIED...WHILE THE GFS HAS A FLATTER FLOW AT THE MID-LEVELS WITH THE TROUGH RETREATING INTO SOUTHEASTERN CANADA. THIS TROUGH RESULTS IN LOW PRESSURE DEVELOPING IN THE GREAT LAKES AND MOVING INTO QUEBEC TUESDAY. THE ECMWF PRODUCES A TRIPLE POINT LOW OVER NEW JERSEY OFF THE MAIN LOW IN QUEBEC AND TRANSLATES THE TRIPLE POINT LOW ALONG THE SOUTHERN NEW ENGLAND COAST. THE GFS DEPICTS NO SUCH REDEVELOPMENT BUT KEEPS A STRONG SOUTHERLY FLOW AHEAD OF THE COLD FRONT EXTENDING FROM THE QUEBEC LOW. THESE DIFFERENCES COULD AFFECT THE OVERALL NATURE OF THE RAIN /WHETHER ITS MORE STRATIFORM OR SHOWERY/ BUT REGARDLESS OF THE NATURE OR THE TYPE OF SYSTEM...TUESDAY IS LIKELY TO BE WET. MODELS HINT THAT THE RAIN COULD MOVE INTO OUR WESTERN ZONES LATE MONDAY NIGHT INTO EARLY TUESDAY MORNING...BUT THE BULK OF THE RAIN APPEARS TO HOLD OFF TIL AFTER 12Z TUESDAY. RAIN CONTINUES THROUGH TUESDAY INTO THE FIRST PART OF THE DAY ON WEDNESDAY BUT THEN WILL TAPER OFF AS EITHER THE FRONT MOVES THROUGH OR THE LOW PRESSURE EJECTS TOWARDS THE MARITIMES. THE REMAINDER OF THE WEEK LOOKS TO BE DRY WITH A POSSIBILITY OF A FEW DIURNAL SHOWERS HERE AND THERE EACH DAY. TEMPERATURES ARE EXPECTED TO BE BELOW TO NEAR NORMAL UNTIL THE WEEKEND WHEN DEPENDING ON THE MODEL COULD SEE A RETURN TO AUGUST HEAT AND HUMIDITY. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 00Z UPDATE...HIGH CONFIDENCE. VFR TONIGHT WITH LIGHT N/NE WINDS. SHOULD SEE MVFR CIGS SPREAD FROM OCEAN ONTO CAPE COD AND ISLANDS EARLY SUN MORNING. SOME QUESTION AS TO WHETHER OR NOT CIGS SCT OUT OR LIFT TO VFR SUN AFTERNOON. FOR NOW WE THINK CIGS WILL REMAIN MVFR THROUGH MUCH OF DAY AND INTO SUN NIGHT. OTHERWISE VFR ELSEWHERE WITH BRIEF SHOWER POSSIBLE ACROSS NW MA SUN AFTERNOON. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /MONDAY THROUGH THURSDAY/... MONDAY...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR/IFR CIGS/VSBYS ENTERING WESTERN ZONES LATE MONDAY NIGHT WITH -RA. TUESDAY...MODERATE CONFIDENCE. MVFR/IFR CONDITIONS LIKELY IN WIDESPREAD RAIN/FOG. WEDNESDAY...MODERATE CONFIDENCE. LINGERING MVFR/IFR CONDITIONS IN DEPARTING RAIN. IMPROVING CONDITIONS THROUGH THE DAY. THURSDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF BRIEF MVFR CONDITIONS IN DIURNAL -SHRA. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH SUN NIGHT. DROPPED SCA ON OUTER S COASTAL WATERS WHERE SEAS HAVE SUBSIDED. LIGHT N/NE WINDS GIVE WAY TO INCREASING NE WINDS SUN AND ESPECIALLY SUN NIGHT...AS LOW PRESSURE PASSES WELL SE OF NEW ENGLAND. SEAS SHOULD BEGIN TO BUILD LATER IN DAY AND COULD REACH 5 FT BY SUN NIGHT E AND S OF NANTUCKET...WHICH MAY REQUIRE SCA IN LATER FORECASTS. DRY WEATHER EXPECTED THROUGH PERIOD. OUTLOOK /MONDAY THROUGH THURSDAY/... MONDAY...HIGH CONFIDENCE. WINDS AND SEAS DIMINISH AS HIGH PRESSURE BUILDS OVER THE WATERS. TUESDAY...MODERATE CONFIDENCE. WINDS AND SEAS INCREASE AS EITHER A COLD FRONT OR A LOW PRESSURE SYSTEM MOVE OVER THE WATERS. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR SEAS IF NOT WINDS AS WELL. VISIBILITIES MAY BE LIMITED AT TIMES IN RAIN. WEDNESDAY...MODERATE CONFIDENCE. WINDS AND SEAS DIMINISH AS LOW PRESSURE PULLS AWAY FROM SOUTHERN NEW ENGLAND. THURSDAY...MODERATE CONFIDENCE. QUIET BOATING WEATHER EXPECTED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...RLG/JWD NEAR TERM...RLG/JWD SHORT TERM...JWD LONG TERM...RLG AVIATION...RLG/JWD MARINE...RLG/JWD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
315 PM EDT SAT AUG 8 2015 .SYNOPSIS... HIGH PRESSURE WILL MAINTAIN DRY WEATHER THROUGH SUN AS LOW PRESSURE REMAINS WELL OFFSHORE...THOUGH A SPOT SHOWER IS POSSIBLE ACROSS THE INTERIOR SUN AFTERNOON. LOW PRESSURE WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS AT TIMES MON NIGHT INTO WED MORNING. A TREND TOWARD DRIER WEATHER IS LIKELY THROUGH THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 315 PM UPDATE... PLENTY OF DIURNAL CU ACROSS INTERIOR WHERE HRRR AND 12Z NAM WANT TO BRING SOME ISOLATED SHOWER ACTIVITY THIS AFTERNOON. COLUMN IS FAIRLY DRY SO AM NOT BUYING INTO THAT...MODELS ARE MORE LIKELY INDICATING BUILDING CU WHICH IS EVIDENT ON SATELLITE NEAR BERKSHIRES. MEANWHILE COASTAL LOW IS THROWING BACK SOME PATCHY MID AND HIGH CLOUDS ALONG S COAST...CAPE COD AND ISLANDS. EXPECT THESE CLOUDS TO THICKEN UP TONIGHT BUT NO RAIN EXPECTED AS BEST LIFT STAYS OFFSHORE WITH PROGRESSIVE UPPER FLOW. SOME OF HIGH-RES MODELS /HRRR...RAP AND ARW-WRF/ WANT TO BRING RAINFALL TO SE NEW ENGLAND LATER TONIGHT BUT THAT LOOKS TO BE OVERDONE. ANOTHER PLEASANTLY COOL NIGHT AHEAD WITH GOOD RADIATIONAL COOLING CONDITIONS AWAY FROM INFLUENCE OF MID/HIGH CLOUDS NEAR S COAST. LEANED TOWARD COOLER GFS LAMP GUIDANCE WHICH BRINGS LOWS INTO UPPER 40S ACROSS NW MA AND MAINLY 50S ELSEWHERE. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... EXPECTING A GOOD AMOUNT OF CLOUDINESS NEAR CAPE COD AND ISLANDS SUN DUE TO INCREASING NE FLOW ON PERIPHERY OF COASTAL LOW. MODEL CROSS SECTIONS SHOW GOOD AMOUNT OF LOW LEVEL MOISTURE BELOW 950 MB WHICH SHOULD BECOME TRAPPED. NO REAL MECHANISM FOR RAINFALL SO DRY WEATHER ANTICIPATED AS DEEPER MOISTURE AND LIFT REMAIN WELL OFFSHORE. SOME QUESTION AS TO WHETHER OR NOT LOW CLOUDS WILL BREAK DURING AFTERNOON...BUT FOR NOW LEANED TOWARD THEM HANGING ON. ACROSS INTERIOR...MODELS CONTINUE TO HINT AT POSSIBILITY OF FEW SHOWERS BY AFTERNOON DUE TO SUBTLE LIFT FROM UPPER TROUGH. LOW LEVEL CONVERGENCE IS MINIMAL DUE TO WEAK WIND FIELDS...SO ANY ACTIVITY WOULD BE TIED TO TERRAIN. STABILITY PARAMETERS MARGINAL SO EXPECT AN ISOLATED SHOWER OR PERHAPS A THUNDERSTORM ACROSS NW AND POSSIBLY N CENTRAL MA. HIGHS SHOULD BE A LITTLE COOLER THAN TODAY...ESPECIALLY NEAR COAST DUE TO NE FLOW AND CLOUDINESS...RANGING FROM AROUND 70 ON OUTER CAPE TO AROUND 80 FARTHER INLAND. SUBSIDENCE AND SOME DRYING SUN NIGHT SHOULD LEAD TO AT LEAST PARTIAL CLEARING...BUT CONTINUED ONSHORE FLOW MAY KEEP CLOUDS LOCKED IN CLOSER TO COAST. LOWS SHOULD DROP BACK INTO 50S AND LOWER 60S. && .LONG TERM /MONDAY THROUGH SATURDAY/... HIGHLIGHTS... * UNSETTLED WEATHER LIKELY LATE MON NIGHT THROUGH WED MORNING * TEMPS SLIGHTLY BELOW NORMAL FOR MUCH OF THE WEEK * POSSIBLE RETURN TO AUGUST HEAT FOR SATURDAY OVERALL...MODELS ARE IN DECENT AGREEMENT THROUGH MUCH OF THE LONG TERM. THERE ARE A COUPLE OF DISCREPANCIES THAT CONTINUE THROUGH THE PERIOD. AS FAR AS SENSIBLE WEATHER GOES...THE MODELS ARE IN AGREEMENT. LOOKING AT AN UPPER LEVEL TROUGH IN THE GREAT LAKES MONDAY SLOWLY MOVING EASTWARD OVER THE NORTHEAST AND NEW ENGLAND BY WEDNESDAY AND POTENTIALLY STALLING THERE THROUGH THE END OF THE FORECAST PERIOD. THE ECMWF KEEPS THE PATTERN MORE AMPLIFIED...WHILE THE GFS HAS A FLATTER FLOW AT THE MID-LEVELS WITH THE TROUGH RETREATING INTO SOUTHEASTERN CANADA. THIS TROUGH RESULTS IN LOW PRESSURE DEVELOPING IN THE GREAT LAKES AND MOVING INTO QUEBEC TUESDAY. THE ECMWF PRODUCES A TRIPLE POINT LOW OVER NEW JERSEY OFF THE MAIN LOW IN QUEBEC AND TRANSLATES THE TRIPLE POINT LOW ALONG THE SOUTHERN NEW ENGLAND COAST. THE GFS DEPICTS NO SUCH REDEVELOPMENT BUT KEEPS A STRONG SOUTHERLY FLOW AHEAD OF THE COLD FRONT EXTENDING FROM THE QUEBEC LOW. THESE DIFFERENCES COULD AFFECT THE OVERALL NATURE OF THE RAIN /WHETHER ITS MORE STRATIFORM OR SHOWERY/ BUT REGARDLESS OF THE NATURE OR THE TYPE OF SYSTEM...TUESDAY IS LIKELY TO BE WET. MODELS HINT THAT THE RAIN COULD MOVE INTO OUR WESTERN ZONES LATE MONDAY NIGHT INTO EARLY TUESDAY MORNING...BUT THE BULK OF THE RAIN APPEARS TO HOLD OFF TIL AFTER 12Z TUESDAY. RAIN CONTINUES THROUGH TUESDAY INTO THE FIRST PART OF THE DAY ON WEDNESDAY BUT THEN WILL TAPER OFF AS EITHER THE FRONT MOVES THROUGH OR THE LOW PRESSURE EJECTS TOWARDS THE MARITIMES. THE REMAINDER OF THE WEEK LOOKS TO BE DRY WITH A POSSIBILITY OF A FEW DIURNAL SHOWERS HERE AND THERE EACH DAY. TEMPERATURES ARE EXPECTED TO BE BELOW TO NEAR NORMAL UNTIL THE WEEKEND WHEN DEPENDING ON THE MODEL COULD SEE A RETURN TO AUGUST HEAT AND HUMIDITY. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 18Z UPDATE...HIGH CONFIDENCE. VFR THIS AFTERNOON AND TONIGHT WITH LIGHT N/NE WINDS. SEA BREEZE ALONG E MA COAST THIS AFTERNOON WHICH KEEP WINDS MORE E OR SE. SHOULD SEE MVFR CIGS SPREAD FROM OCEAN ONTO CAPE COD AND ISLANDS EARLY SUN MORNING. SOME QUESTION AS TO WHETHER OR NOT CIGS SCT OUT OR LIFT TO VFR SUN AFTERNOON. FOR NOW WE THINK CIGS WILL REMAIN MVFR THROUGH MUCH OF DAY AND INTO SUN NIGHT. OTHERWISE VFR ELSEWHERE WITH BRIEF SHOWER POSSIBLE ACROSS NW MA SUN AFTERNOON. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /MONDAY THROUGH THURSDAY/... MONDAY...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR/IFR CIGS/VSBYS ENTERING WESTERN ZONES LATE MONDAY NIGHT WITH -RA. TUESDAY...MODERATE CONFIDENCE. MVFR/IFR CONDITIONS LIKELY IN WIDESPREAD RAIN/FOG. WEDNESDAY...MODERATE CONFIDENCE. LINGERING MVFR/IFR CONDITIONS IN DEPARTING RAIN. IMPROVING CONDITIONS THROUGH THE DAY. THURSDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF BRIEF MVFR CONDITIONS IN DIURNAL -SHRA. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH SUN NIGHT. DROPPED SCA ON OUTER S COASTAL WATERS WHERE SEAS HAVE SUBSIDED. LIGHT N/NE WINDS GIVE WAY TO INCREASING NE WINDS SUN AND ESPECIALLY SUN NIGHT...AS LOW PRESSURE PASSES WELL SE OF NEW ENGLAND. SEAS SHOULD BEGIN TO BUILD LATER IN DAY AND COULD REACH 5 FT BY SUN NIGHT E AND S OF NANTUCKET...WHICH MAY REQUIRE SCA IN LATER FORECASTS. DRY WEATHER EXPECTED THROUGH PERIOD. OUTLOOK /MONDAY THROUGH THURSDAY/... MONDAY...HIGH CONFIDENCE. WINDS AND SEAS DIMINISH AS HIGH PRESSURE BUILDS OVER THE WATERS. TUESDAY...MODERATE CONFIDENCE. WINDS AND SEAS INCREASE AS EITHER A COLD FRONT OR A LOW PRESSURE SYSTEM MOVE OVER THE WATERS. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR SEAS IF NOT WINDS AS WELL. VISIBILITIES MAY BE LIMITED AT TIMES IN RAIN. WEDNESDAY...MODERATE CONFIDENCE. WINDS AND SEAS DIMINISH AS LOW PRESSURE PULLS AWAY FROM SOUTHERN NEW ENGLAND. THURSDAY...MODERATE CONFIDENCE. QUIET BOATING WEATHER EXPECTED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...RLG/JWD NEAR TERM...JWD SHORT TERM...JWD LONG TERM...RLG AVIATION...RLG/JWD MARINE...RLG/JWD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
128 PM EDT SAT AUG 8 2015 .SYNOPSIS... HIGH PRESSURE WILL MAINTAIN DRY WEATHER THIS AFTERNOON AS LOW PRESSURE REMAINS WELL OFFSHORE. A SPOT SHOWER IS POSSIBLE ON SUNDAY. DRY WEATHER LINGERS INTO MONDAY. A LOW PRESSURE WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS AT TIMES MONDAY NIGHT INTO WEDNESDAY. A TREND TOWARD DRIER WEATHER IS LIKELY THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 130 PM UPDATE... PLENTY OF DIURNAL CU ACROSS INTERIOR WHERE HRRR AND 12Z NAM WANT TO BRING SOME ISOLATED SHOWER ACTIVITY THIS AFTERNOON. COLUMN IS FAIRLY DRY SO AM NOT BUYING INTO THAT...MODELS ARE MORE LIKELY INDICATING BUILDING CU. COASTAL LOW IS THROWING BACK SOME PATCHY MID AND HIGH CLOUDS NEAR S COAST BUT DO NOT EXPECT THAT TO BE MUCH OF AN ISSUE. FORECAST HIGHS IN 70S/LOWER 80S ON TRACK. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT... SECONDARY LOW PRES WILL ONCE AGAIN SLIDE WELL S OF THE REGION. THE INCREASE IN ISALLOBARIC FLOW WILL KEEP INTERIOR WINDS A BIT HIGHER AND LEFTOVER CLOUDS ARE LIKELY TO LEAD TO WARMER MINS...ALTHOUGH STILL IN THE UPPER 50S AND LOW 60S. DRY WX REMAINS THOUGH AS THE PRECIP SHIELD SHOULD REMAIN WELL SE OF THE REGION...EVEN ACK. SUN... A BIT TRICKIER FORECAST FOR SUN. THERE ARE DIFFERENCES IN QPF OUTPUT ACROSS THE INTERIOR OF MA/CT. NAM/MESOSCALE GUIDANCE IS MOST ROBUST WHILE GFS/ECMWF ARE DRIER. THIS IS REFLECTED IN BUFKIT SOUNDINGS...WITH NAM MORE MOIST AND AND GFS DRIER. PWATS ARE DIFFERENT ALSO...WITH NEARLY 1 STD DEVIATION ABOVE NORMAL IN THE NAM...NEAR NORMAL IN THE GFS/ECMWF. THERE IS A LIFT SOURCE IN THE FORM OF A WEAK...BUT FAST MOVING SHORTWAVE WHICH SHOW SOME TIMING DIFFERENCES. THEREFORE...CAN/T RULE OUT A SPOT SHOWER MAINLY FOR WRN MA OR CT...BUT THE PRECIP SHIELD ASSOCIATED WITH LOW PRES OFFSHORE REMAINS OFFSHORE. HOWEVER...CHANCE POPS WILL BE THE MAX AS THEY ARE LIKELY TO BE FAIRLY SCATTERED AND RELATIVELY LIGHT GIVEN THE LOWER END PWATS. WILL ALSO INCLUDE THUNDER AS EACH MODEL SHOWS MODEST SFC CAPE...PARTICULARLY IF THE NAM VERIFIES. TEMPS REMAIN BELOW NORMAL UNDER RENEWED NE FLOW WITH LOW PRES NEAR THE BENCHMARK. RANG BETWEEN LOW 70S AND LOW 80S EXPECTED. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * SCATTERED SHOWERS/T-STORMS AT TIMES LATE MONDAY INTO WEDNESDAY * TEMPERATURES NEAR OR SLIGHTLY LOWER THAN NORMAL SYNOPTIC OVERVIEW... BROAD...FLAT MID-LEVEL FLOW OVER THE NORTHERN USA EVENTUALLY AMPLIFIES INTO A MID-LEVEL TROUGH OVER THE EASTERN USA TOWARD THE MIDDLE OF NEXT WEEK. THIS RESULTS IN AN ACTIVE PATTERN LATE MONDAY INTO WEDNESDAY FOR SOUTHERN NEW ENGLAND. ENSEMBLES AND DETERMINISTIC GUIDANCE ARE IN RATHER GOOD AGREEMENT ON THE LARGE SCALE FLOW...ALONG WITH THE AMPLITUDE. BUT AS USUAL AT THIS TIME RANGE...ARE STRUGGLING WITH THE INDIVIDUAL FRONTAL WAVES AND EXACT TIMING. THUS FOLLOWED A MODEL BLEND FOR THIS PORTION OF THE FORECAST. DAILY SENSIBLE WEATHER DETAILS... SUNDAY NIGHT AND MONDAY...MOST OF THE GUIDANCE SUGGESTS DRY WEATHER...ESPECIALLY FOR RI AND EASTERN MA...WITH A LOW RISK OF SHOWER/T-STORMS LATE MONDAY FOR WESTERN MA AS MID LEVEL TROUGH APPROACHES. TUESDAY AND WEDNESDAY...MID LEVEL TROUGH AND ATTENDING FRONTAL WAVE APPROACH. INCREASED RISK FOR SHOWERS AND THUNDERSTORMS. VERY MOIST AIR EXPECTED...WITH DEW POINTS IN THE MID TO UPPER 60S. GIVEN MID LEVEL TROUGH AMPLITUDE...AT LEAST MODEST FORCING FOR ASCENT IS EXPECTED. THIS COMBINATION WILL RESULT IN A RISK FOR HEAVY DOWNPOURS. WIND FIELDS ALOFT ARE MODEST...BUT INSTABILITY APPEARS MARGINAL. GIVEN THE TIME RANGE HERE A LOW RISK OF STRONG STORMS. THURSDAY AND FRIDAY...LATEST GUIDANCE CONTINUES TO SUGGEST THE MID LEVEL TROUGH OVER THE NORTHEAST SHOULD BEGIN TO DEAMPLIFY. THIS WILL RESULT IN A TREND TOWARD DRIER AND WARMER WEATHER LATE NEXT WEEK. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 18Z UPDATE...HIGH CONFIDENCE. VFR THIS AFTERNOON AND TONIGHT WITH LIGHT N/NE WINDS. SEA BREEZE ALONG E MA COAST THIS AFTERNOON WHICH KEEP WINDS MORE E OR SE. SHOULD SEE MVFR CIGS SPREAD FROM OCEAN ONTO CAPE COD AND ISLANDS EARLY SUN MORNING. SOME QUESTION AS TO WHETHER OR NOT CIGS SCT OUT OR LIFT TO VFR SUN AFTERNOON. FOR NOW WE THINK CIGS WILL REMAIN MVFR THROUGH MUCH OF DAY AND INTO SUN NIGHT. OTHERWISE VFR ELSEWHERE WITH BRIEF SHOWER POSSIBLE ACROSS NW MA SUN AFTERNOON. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /MONDAY THROUGH WEDNESDAY/... FORECAST CONFIDENCE...HIGH CONFIDENCE MONDAY...THEN MODERATE CONFIDENCE TUESDAY AND WEDNESDAY. MONDAY...VFR WITH LOW RISK OF SHOWERS/T-STORMS LATE WESTERN MA/CT TUESDAY AND WEDNESDAY...UNSETTLED. SCATTERED SHOWERS/THUNDERSTORMS. MVFR TO IFR POSSIBLE. HEAVY DOWNPOURS POSSIBLE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SUNDAY/... LIGHT N/NE FLOW THIS AFTERNOON ON WATERS. LEAVING SCA POSTED FOR SEAS ON OUTER S COASTAL WATERS BUT CERTAINLY LOOKS MARGINAL AND MAY DROP WITH 4 PM FORECAST. TONIGHT INTO TOMORROW...MODERATE CONFIDENCE. NORTH TO NORTHEAST FLOW REMAINS...BUT SHOULD BE GENERALLY BELOW THE 25 KT THRESHOLD THANKS TO INFLUENCE OF HIGH PRES TO THE N. THIS SHOULD ALSO KEEP SEAS BELOW 5 FEET...BUT THE PERSISTENT FLOW MAY INCREASE SWELLS ALONG THE E COAST. FOR NOW...NOT CONFIDENT ENOUGH FOR AN SMALL CRAFT ADVISORIES...BUT WILL NEED TO WATCH. OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/... SUNDAY NIGHT...LIGHT E/NE WINDS. STRONGER WINDS SE OF NANTUCKET. E SWELLS 3-5 FT. MONDAY...WEAK HIGH PRESSURE. DRY WEATHER. LIGHT WINDS WITH SUBSIDING EAST SWELLS. TUESDAY AND WEDNESDAY...UNSETTLED...WITH SHOWERS AND THUNDERSTORMS AS A FRONTAL WAVE APPROACHES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ254- 255. && $$ SYNOPSIS...BELK/DOODY NEAR TERM...JWD SHORT TERM...DOODY LONG TERM...BELK AVIATION...JWD MARINE...JWD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1009 PM CDT SUN AUG 9 2015 .SHORT TERM... 219 PM CDT THROUGH MONDAY... THINKING THIS AFTERNOON AND EVENING WILL BE RELATIVELY QUIET AND POSSIBLY QUIETER THAN WHAT IS CURRENTLY FORECAST. STRAY SHOWERS ARE OUT OVER THE LAKE AND SOUTH OF I-80 NEAR OTTAWA AND OVER NW INDIANA. THE MCV FROM THIS MORNING/S COMPLEX IS SPINNING OVER WESTERN MO AND SOUTHERN IL BASED ON SATELLITE DATA WITH NEW CONVECTION FIRING OVER NORTHERN MO. THE LATEST RAP ANALYSIS INDICATES THERE IS ABOUT 500 J/KG OF CAPE OVER THE FAR SOUTHERN CWA WITH LITTLE TO NO CAPE OVER THE REST OF THE CWA. GUIDANCE IS STRUGGLING WITH WHERE CONVECTION WILL FIRE GOING INTO THIS AFTN AND HAVE LOW CONFIDENCE IN THE EXACT DETAILS MYSELF. THINKING THE MAJORITY OF CONVECTION WILL OCCUR TO THE WEST AND SOUTH OF THE CWA...BUT CANNOT RULE OUT A FEW SHOWERS AND/OR STORMS AS THE MCV SHIFTS EAST OVER SOUTHERN IL. LOWERED PRECIP CHANCES INTO THE CHANCE RANGE BELOW 50% AT BEST WITH THE HIGHEST VALUES SOUTH OF I- 80. WHILE STORMS MAY PRODUCE HEAVY DOWNPOURS AND A GUST OF WIND...SEVERE WEATHER IS NOT EXPECTED. ONCE AGAIN...AREAS NORTH OF I-88 MAY END UP BEING DRY BUT DID NOT HAVE ENOUGH CONFIDENCE TO GO DRY AT THIS TIME. LONG STORY SHORT...ISOLATED SHOWERS ARE POSSIBLE NORTH OF I-80 WITH ISOLATED TO SCATTERED SHOWERS AND A FEW STORMS SOUTH OF I-80. AS THE MCV SHIFTS EAST THIS EVENING...THE THREAT OF SHOWERS AND STORMS WILL ALSO SHIFT TO LOCATIONS ALONG AND EAST OF I-55. EXPECTING FOG TO DEVELOP OVERNIGHT AS WINDS DIMINISH AND SATURATED AIR COOLS. SOME AREAS MAY SEE DENSE FOG...VSBY OF 1/4 A MILE OR LESS...BUT AS OF RIGHT NOW EXPECTING MOSTLY AREAS OF FOG WITH VSBY GREATER THAN 1/4 OF A MILE. A SHORTWAVE TROUGH TRAVELS ACROSS WI TOMORROW WITH VORTICITY STREAMERS PASSING OVER FAR NORTHERN IL. THINKING SCATTERED SHOWERS AND STORMS WILL FORM ALONG THE VORT STREAMERS WITH BETTER COVERAGE NORTH OF I-80 ESPECIALLY ALONG THE WI/IL STATE LINE. THINKING COVERAGE WILL BE HIT OR MISS WITH PLENTY OF RAIN FREE HOURS. DID NOT MAKE MANY CHANGES TO HIGH TEMPS MONDAY WITH COOLER AIR SINKING IN FROM THE NORTH AND THICK CLOUD COVER. EXPECTING HIGHS AROUND 80 ALONG THE IL/WI STATE LINE AND ALONG THE LAKE WITH LOW TO MID 80S SOUTH OF I-80. JEE && .LONG TERM... MONDAY NIGHT THROUGH SUNDAY... 251 PM...MAIN FORECAST CONCERN IS THE CHANCE OF THUNDERSTORMS THURSDAY NIGHT THRU FRIDAY NIGHT. WEAK LOW PRESSURE IS EXPECTED TO BE EAST OF THE AREA AND MOVING ACROSS THE SOUTHERN GREAT LAKES REGION MONDAY EVENING. THERE IS A SLIGHT CHANCE OF AN EVENING SHOWER OR THUNDERSTORM BUT ANY ACTIVITY SHOULD BE QUICKLY DIMINISHING BY MID/LATE EVENING. HIGH PRESSURE THEN BUILDS ACROSS THE REGION TUESDAY AND WEDNESDAY. NORTHERLY WINDS MAY BE A BIT BREEZY NEAR THE LAKE INTO NORTHWEST INDIANA TUESDAY WITH THE CENTER OF THE HIGH STILL WEST OF THE AREA WITH CONTINUED LIGHTER NORTHERLY WINDS ON WEDNESDAY...WITH COOLER TEMPS AT THE LAKESHORE BOTH DAYS. WEDNESDAY NIGHT/THURSDAY MORNING WILL BE A BIT COOLER WITH LOWS POSSIBLY IN THE MID/UPPER 50S AWAY FROM THE URBAN AREAS. BUT AS THE HIGH SHIFTS EAST THURSDAY...WARMER SOUTHWESTERLY FLOW WILL RETURN WITH WINDS PERHAPS BECOMING BREEZY THURSDAY AFTERNOON. HIGHS WILL LIKELY REBOUND INTO THE MID 80S THOUGH STILL SOME DIFFERENCES REGARDING HOW MUCH WARMER TEMPS COULD BECOME. DIFFERENCES BEGIN TO SHOW UP FRIDAY AND FRIDAY NIGHT WITH THE GFS BRINGING A FRONTAL BOUNDARY ACROSS THE AREA FRIDAY AFTERNOON/ EVENING WHILE THE ECMWF KEEPS THIS FRONT NORTH OF THE CWA. A LITTLE TOO EARLY TO DETERMINE SPECIFICS BUT GRADIENT APPEARS LIGHT ENOUGH THAT A LAKE BREEZE IS POSSIBLE FRIDAY AFTERNOON. PRECIP CHANCES WILL LIKELY DEPEND ON HOW MUCH OF THE FRONTAL BOUNDARY REACHES THE AREA. HAVE LOW CHANCE POPS FOR NOW...BUT CONFIDENCE IS FAIRLY LOW. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * LIGHT SOUTH-SOUTHEAST WINDS EVENTUALLY BACKING TO ESE AND REMAINING BELOW 10 KTS. * GRADUAL LOWERING OF CIG/VIS THROUGH MVFR/IFR OVERNIGHT. A FEW SPOTTY SHOWERS POSSIBLE LATE EVENING. IMPROVEMENT FROM IFR/MVFR EXPECTED DURING MONDAY MORNING. * NORTHERLY WINDS MONDAY...LIKELY BECOMING NORTHEAST WITH LAKE BREEZE DURING THE AFTERNOON. * CHANCE OF ISOLATED/SCATTERED TSRA MONDAY AFTERNOON. RATZER //DISCUSSION...UPDATED 00Z... AREA OF SURFACE LOW PRESSURE OVER THE LOWER MISSOURI VALLEY WILL CONTINUE TO TRACK SOUTHEAST INTO THE LOWER OHIO VALLEY TONIGHT. TO THE NORTH...A SERIES OF MINOR MID-LEVEL DISTURBANCES WILL RIPPLE ACROSS THE FORECAST AREA WITHIN THE ELEVATED FRONTAL ZONE NORTH OF THE SURFACE FRONT. THIS MAY SUPPORT A FEW SPOTTY SHOWERS ESPECIALLY FROM CHICAGO AND AREAS SOUTH AND EAST LATER THIS EVENING. AS MOIST LOW LEVELS COOL NOCTURNALLY...WILL LIKELY SEE DEVELOPMENT OF LOWER CLOUD DECKS/FOG...WHICH IS EXPECTED TO LOWER THROUGH MVFR INTO IFR LATER TONIGHT ESPECIALLY FOR ORD/MDW WHERE LIGHT WINDS EVENTUALLY BECOME MORE EAST/NORTHEAST OFF OF LAKE MICHIGAN. VARIOUS MODELS ARE FAIRLY INSISTENT IN IFR CONDITIONS...POSSIBLY EVEN LIFR...DEVELOPING BY THE PRE-DAWN HOURS...WITH IMPROVEMENT THEN BEGINNING AFTER SUNRISE. LIGHT GENERALLY SOUTH-SOUTHEAST WINDS SHOULD GRADUALLY SHIFT TO FROM SOUTHEAST TO THE NORTH-NORTHEAST THROUGH MONDAY MORNING. WINDS INLAND WILL TREND MORE NNW...THOUGH ORD/MDW/GYY WILL LIKELY MAINTAIN OR REDEVELOP A NE COMPONENT OFF OF THE LAKE IN THE AFTERNOON. ANOTHER UPPER DISTURBANCE AND ONLY SLOW DRYING IN THE LOW LEVELS MAY SUPPORT ISOLATED-SCATTERED TSRA FOR A PERIOD MONDAY AFTERNOON...POSSIBLY ALONG LAKE BREEZE BOUNDARY. RATZER //ORD AND MDW CONFIDENCE...UPDATED 03Z... * MEDIUM-HIGH IN WINDS. * MEDIUM-LOW IN CIG/VIS TRENDS TONIGHT/EARLY MONDAY. * MEDIUM-LOW IN MONDAY AFTERNOON TSRA. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY AND WEDNESDAY...VFR. NORTH-NORTHEAST WINDS. THURSDAY...VFR. SLIGHT CHANCE TSRA THURSDAY NGT. WEST-SOUTHWEST WINDS. FRIDAY...CHANCE TSRA. WEST-SOUTHWEST WINDS. SATURDAY...VFR. NORTHEAST WINDS. RATZER && .MARINE... 251 PM...LOW PRESSURE OVER NORTHERN ONTARIO WILL MOVE INTO QUEBEC BY MONDAY EVENING. A TRAILING COLD FRONT WILL MOVE ACROSS THE LAKE LATE TONIGHT INTO MONDAY MORNING SHIFTING WINDS NORTHERLY. ANOTHER WEAK LOW WILL MOVE SOUTH OF THE LAKE MONDAY AFTERNOON AS HIGH PRESSURE BUILDS INTO THE NORTHERN PLAINS. THE GRADIENT WILL TIGHTEN BETWEEN THESE TWO FEATURES WITH NORTHERLY WINDS INCREASING TO 15-25 KTS BY TUESDAY MORNING. AS THE HIGH MOVES EAST...THESE NORTHERLY WINDS WILL SLOWLY DIMINISH TUESDAY NIGHT INTO WEDNESDAY. WINDS WILL SHIFT TO THE SOUTHWEST WEDNESDAY NIGHT AS THE HIGH SETTLES SOUTHEAST OF THE LAKE AND DEPENDING ON HOW STRONG THE GRADIENT BECOMES...SPEEDS MAY INCREASE INTO THE 15-25KT RANGE THURSDAY INTO THURSDAY NIGHT. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
836 PM CDT SUN AUG 9 2015 .UPDATE... ISSUED AT 825 PM CDT SUN AUG 9 2015 THE BOUNDARY THAT WAS PRODUCED BY THE STORMS THIS MORNING WAS LOCATED OVER SOUTHEAST ILLINOIS BACK INTO EAST CENTRAL MISSOURI. A CLUSTER OF STORMS WAS TRACKING ESE ALONG THIS MESOSCALE FEATURE AND MAY CLIP OUR FAR SOUTHEAST COUNTIES. MEANWHILE...FURTHER TO THE NORTHWEST...A WEAK COOL FRONT WAS LOCATED FROM CENTRAL WISCONSIN SOUTHWEST THROUGH NORTHERN IOWA WITH A BAND OF STORMS OVER PARTS OF NORTHWEST IOWA. THE ACTUAL SYNOPTIC SCALE COOL FRONT TO OUR NORTHWEST IS FORECAST TO PUSH ACROSS THE FORECAST AREA MONDAY MORNING. UNTIL THEN...WILL CONTINUE WITH THE CHANCES FOR SHOWERS AND STORMS...ESPECIALLY ACROSS THE SOUTH OVERNIGHT WITH LOWER POPS AS YOU HEAD NORTH OF I-74. WITH THE ADDED MOISTURE FROM THE RAINFALL TODAY...LIGHT WINDS AND A GRADUAL TREND TOWARDS CLEARING SKIES LATE TONIGHT...FOG WILL BE A CONCERN AND WILL CONTINUE TO HOLD WITH THAT IN THE FORECAST THRU MONDAY MORNING. HAVE MADE SOME MINOR ADJUSTMENTS TO THE RAIN CHANCES...ESPECIALLY ACROSS THE NORTH AND MADE SOME TWEAKS TO THE SKY COVER FOR THE LATE NIGHT HOURS. WE SHOULD HAVE THE UPDATE OUT BY 845 PM. && .SHORT TERM...(TONIGHT) ISSUED AT 253 PM CDT SUN AUG 9 2015 BASED ON SURFACE DATA...APPEARS THERE IS A BOUNDARY STRETCHING FROM NORTHERN MO/SOUTHERN IA INTO NORTHERN PART OF CENTRAL IL. HOWEVER...THE EFFECTIVE BOUNDARY SHOULD BE MUCH FURTHER SOUTH AS A RESULT OF THE MCS THAT MOVED ACROSS THE AREA EARLIER THIS MORNING PUSHING IT SOUTH OF THE CWA. HRRR DOES NOT SHOW ANY PCPN IN THE CWA TONIGHT...BUT DOES HAVE THE SMALL AREA OF PCPN IN NORTHERN MO MOVING EAST-SOUTHEAST INTO SOUTHERN IL THIS EVENING. BUT WITH A WEAK CONVERGENT BOUNDARY IN THE AREA AM INCLINED TO KEEP A CHANCE FOR POPS IN THE FORECAST FOR TONIGHT. TREND SHOULD BE...AND MODELS DO SUPPORT THAT THIS WEAK BOUNDARY SHOULD MOVE SOUTH DURING THE OVERNIGHT PERIOD. SO CHANCE POPS SOUTHEAST OF THE ILLINOIS RIVER TONIGHT. ENDING OF PCPN CHANCES WILL START ALONG THE RIVER AND THEN PROGRESS SOUTHEAST THROUGH THE PERIOD. OTHER ISSUE OVERNIGHT WILL BE FOG DEVELOPMENT. WITH LOTS OF BREAKS IN THE CLOUDS THIS EVENING AND OVERNIGHT...COMBINED WITH THE ABUNDANCE OF LOW LEVEL MOISTURE FROM THE RAIN THIS MORNING...AND LIGHT WINDS...BELIEVE FOG WILL DEVELOP THIS EVENING AND CONTINUE INTO THE OVERNIGHT HOURS. SO HAVE INCLUDED AREAS OF FOG IN THE FORECAST THE NORTHERN AND CENTRAL PARTS OF THE AREA. ONLY PLACE WITHOUT ANY FOG WILL BE AREAS SOUTHEAST OF I-70. OVERNIGHT LOWS AROUND 70S LOOKS REASONABLE WITH COOLEST TEMPS UP NORTH WHERE MORE BREAKS IN CLOUDS SHOULD BE. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 253 PM CDT SUN AUG 9 2015 A FRONTAL BOUNDARY CURRENTLY FROM NORTHERN WISCONSIN TO NORTHERN NEBRASKA WILL PUSH INTO SOUTHEAST ILLINOIS BY MID MORNING MONDAY...AIDED BY SEVERAL AREAS OF THUNDERSTORM DEVELOPMENT AHEAD OF THE FRONT THIS EVENING INTO TONIGHT. THE EFFECTIVE FRONT WILL LIKELY BE LINGERING IN SOUTHEAST PORTIONS OF THE CENTRAL IL FORECAST AREA THROUGH THE MORNING AND HAVE CONTINUED PRECIPITATION CHANCES IN THAT AREA THROUGH NOON. MOST OF THE THUNDERSTORM ACTIVITY WILL TEND TO MOVE EASTWARD THROUGH THE DAY...HOWEVER AN UPPER LEVEL SHORTWAVE WILL APPROACH FROM THE NORTHWEST BY AFTERNOON...AND LIFT ASSOCIATED WITH THIS FEATURE WILL CAUSE CHANCES FOR SHOWERS AND THUNDERSTORMS TO RE-DEVELOP FOR AFTERNOON AND EARLY EVENING...MAINLY FROM THE ILLINOIS RIVER NORTHWESTWARD. HIGHS EXPECTED TO REACH FROM AROUND 81 IN GALESBURG TO THE MID 80S SPRINGFIELD TO PARIS SOUTHWARD WITH WINDS BECOMING NORTHWEST UP TO 10 MPH. AFTER THIS FEATURE PASSES THROUGH...DRY CONDITIONS ARE EXPECTED THROUGH MUCH OF THE WEEK AS A PRONOUNCED UPPER LEVEL RIDGE BUILDS OVER THE CENTRAL U.S. AND TROUGHING OVER THE NORTHEASTERN U.S. A COOL NORTHWEST FLOW PATTERN BETWEEN THE RIDGE AND TROUGH WILL BRING HIGH TEMPERATURES PRIMARILY IN THE LOW 80S AND LOWS IN THE LOW 60S THROUGH THURSDAY. A COLD FRONT EMBEDDED IN THIS FLOW PATTERN WILL DROP INTO THE GREAT LAKES/MIDWEST AREA FRIDAY. MODELS CONTINUE SOME RUN TO RUN INCONSISTENCIES FOR THIS FEATURE...BUT BULK OF GUIDANCE CONTINUES TO SUGGEST PRECIPITATION ASSOCIATED WITH THIS FEATURE MAY STRUGGLE TO REACH AS FAR SOUTHWEST AS CENTRAL ILLINOIS. THEREFORE...HAVE INCORPORATED SLIGHT CHANCES FOR THUNDERSTORMS MAINLY I-72 NORTHWARD. DRY CONDITIONS SHOULD THEN RETURN THROUGH THE WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 600 PM CDT SUN AUG 9 2015 MAIN CONCERN THIS PERIOD WILL BE WITH COVERAGE OF ANY CONVECTION THAT MAY REDEVELOP...ESPECIALLY AT SPI AND DEC...AND THE FOG AND STRATUS THREAT LATER TONIGHT. BOUNDARY LEFT OVER FROM THE MORNING CONVECTION HAS SLIPPED SOUTH OF THE TAF SITES AND APPEARS THAT IT WILL BE THE PRIMARY FOCUS FOR SHOWERS AND STORMS TONIGHT. A SECOND FRONT WELL TO OUR NORTHWEST WILL PUSH INTO OUR AREA MONDAY MORNING. WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE THIS EVENING AT SPI AND DEC WITH THE PRIMARY THREAT FOR STORMS SHIFTING SOUTH OF I72 CLOSER TO I-70 BY LATE EVENING. THEN THE FOCUS SHIFTS TOWARDS FOG AS ABUNDANT LOW LEVEL MOISTURE FROM THIS MORNING`S RAIN COMBINED WITH A LIGHT WIND FLOW WILL BRING ABOUT LOW CIGS AND VSBYS LATE TONIGHT INTO MONDAY MORNING. MOST OF THE FORECAST MODELS BRING CIGS DOWN TO MVFR WITH SOME TEMPO IFR CIGS AND VSBYS IN STRATUS AND FOG EARLY MONDAY MORNING SO WILL CONTINUE FROM PREVIOUS TRENDS IN BRINGING THE VSBYS AND CIGS DOWN AFTER 03Z. WHAT FOG/STRATUS WE DO SEE OVERNIGHT SHOULD DISSIPATE BY 13Z WITH SOME SCT-BKN CUMULUS FROM 2500-3500 FEET. SURFACE WINDS SHOULD BE LIGHT AND VARIABLE TONIGHT AND THEN BECOME NORTHWEST TO NORTH AT 10 TO 15 KTS BY AFTERNOON. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SMITH SHORT TERM...AUTEN LONG TERM...ONTON AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
653 PM CDT SUN AUG 9 2015 .SHORT TERM... 219 PM CDT THROUGH MONDAY... THINKING THIS AFTERNOON AND EVENING WILL BE RELATIVELY QUIET AND POSSIBLY QUIETER THAN WHAT IS CURRENTLY FORECAST. STRAY SHOWERS ARE OUT OVER THE LAKE AND SOUTH OF I-80 NEAR OTTAWA AND OVER NW INDIANA. THE MCV FROM THIS MORNING/S COMPLEX IS SPINNING OVER WESTERN MO AND SOUTHERN IL BASED ON SATELLITE DATA WITH NEW CONVECTION FIRING OVER NORTHERN MO. THE LATEST RAP ANALYSIS INDICATES THERE IS ABOUT 500 J/KG OF CAPE OVER THE FAR SOUTHERN CWA WITH LITTLE TO NO CAPE OVER THE REST OF THE CWA. GUIDANCE IS STRUGGLING WITH WHERE CONVECTION WILL FIRE GOING INTO THIS AFTN AND HAVE LOW CONFIDENCE IN THE EXACT DETAILS MYSELF. THINKING THE MAJORITY OF CONVECTION WILL OCCUR TO THE WEST AND SOUTH OF THE CWA...BUT CANNOT RULE OUT A FEW SHOWERS AND/OR STORMS AS THE MCV SHIFTS EAST OVER SOUTHERN IL. LOWERED PRECIP CHANCES INTO THE CHANCE RANGE BELOW 50% AT BEST WITH THE HIGHEST VALUES SOUTH OF I- 80. WHILE STORMS MAY PRODUCE HEAVY DOWNPOURS AND A GUST OF WIND...SEVERE WEATHER IS NOT EXPECTED. ONCE AGAIN...AREAS NORTH OF I-88 MAY END UP BEING DRY BUT DID NOT HAVE ENOUGH CONFIDENCE TO GO DRY AT THIS TIME. LONG STORY SHORT...ISOLATED SHOWERS ARE POSSIBLE NORTH OF I-80 WITH ISOLATED TO SCATTERED SHOWERS AND A FEW STORMS SOUTH OF I-80. AS THE MCV SHIFTS EAST THIS EVENING...THE THREAT OF SHOWERS AND STORMS WILL ALSO SHIFT TO LOCATIONS ALONG AND EAST OF I-55. EXPECTING FOG TO DEVELOP OVERNIGHT AS WINDS DIMINISH AND SATURATED AIR COOLS. SOME AREAS MAY SEE DENSE FOG...VSBY OF 1/4 A MILE OR LESS...BUT AS OF RIGHT NOW EXPECTING MOSTLY AREAS OF FOG WITH VSBY GREATER THAN 1/4 OF A MILE. A SHORTWAVE TROUGH TRAVELS ACROSS WI TOMORROW WITH VORTICITY STREAMERS PASSING OVER FAR NORTHERN IL. THINKING SCATTERED SHOWERS AND STORMS WILL FORM ALONG THE VORT STREAMERS WITH BETTER COVERAGE NORTH OF I-80 ESPECIALLY ALONG THE WI/IL STATE LINE. THINKING COVERAGE WILL BE HIT OR MISS WITH PLENTY OF RAIN FREE HOURS. DID NOT MAKE MANY CHANGES TO HIGH TEMPS MONDAY WITH COOLER AIR SINKING IN FROM THE NORTH AND THICK CLOUD COVER. EXPECTING HIGHS AROUND 80 ALONG THE IL/WI STATE LINE AND ALONG THE LAKE WITH LOW TO MID 80S SOUTH OF I-80. JEE && .LONG TERM... MONDAY NIGHT THROUGH SUNDAY... 251 PM...MAIN FORECAST CONCERN IS THE CHANCE OF THUNDERSTORMS THURSDAY NIGHT THRU FRIDAY NIGHT. WEAK LOW PRESSURE IS EXPECTED TO BE EAST OF THE AREA AND MOVING ACROSS THE SOUTHERN GREAT LAKES REGION MONDAY EVENING. THERE IS A SLIGHT CHANCE OF AN EVENING SHOWER OR THUNDERSTORM BUT ANY ACTIVITY SHOULD BE QUICKLY DIMINISHING BY MID/LATE EVENING. HIGH PRESSURE THEN BUILDS ACROSS THE REGION TUESDAY AND WEDNESDAY. NORTHERLY WINDS MAY BE A BIT BREEZY NEAR THE LAKE INTO NORTHWEST INDIANA TUESDAY WITH THE CENTER OF THE HIGH STILL WEST OF THE AREA WITH CONTINUED LIGHTER NORTHERLY WINDS ON WEDNESDAY...WITH COOLER TEMPS AT THE LAKESHORE BOTH DAYS. WEDNESDAY NIGHT/THURSDAY MORNING WILL BE A BIT COOLER WITH LOWS POSSIBLY IN THE MID/UPPER 50S AWAY FROM THE URBAN AREAS. BUT AS THE HIGH SHIFTS EAST THURSDAY...WARMER SOUTHWESTERLY FLOW WILL RETURN WITH WINDS PERHAPS BECOMING BREEZY THURSDAY AFTERNOON. HIGHS WILL LIKELY REBOUND INTO THE MID 80S THOUGH STILL SOME DIFFERENCES REGARDING HOW MUCH WARMER TEMPS COULD BECOME. DIFFERENCES BEGIN TO SHOW UP FRIDAY AND FRIDAY NIGHT WITH THE GFS BRINGING A FRONTAL BOUNDARY ACROSS THE AREA FRIDAY AFTERNOON/ EVENING WHILE THE ECMWF KEEPS THIS FRONT NORTH OF THE CWA. A LITTLE TOO EARLY TO DETERMINE SPECIFICS BUT GRADIENT APPEARS LIGHT ENOUGH THAT A LAKE BREEZE IS POSSIBLE FRIDAY AFTERNOON. PRECIP CHANCES WILL LIKELY DEPEND ON HOW MUCH OF THE FRONTAL BOUNDARY REACHES THE AREA. HAVE LOW CHANCE POPS FOR NOW...BUT CONFIDENCE IS FAIRLY LOW. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * LIGHT SOUTH-SOUTHEAST WINDS EARLY THIS EVENING EVENTUALLY BACKING TO ESE...BUT REMAINING BELOW 10 KTS. * GRADUAL LOWERING OF CIG/VIS THROUGH MVFR/IFR LATER THIS EVENING AND OVERNIGHT. A FEW SPOTTY SHOWERS POSSIBLE LATE EVENING. IMPROVEMENT FROM IFR/MVFR EXPECTED DURING MONDAY MORNING. * NORTHERLY WINDS MONDAY...LIKELY BECOMING NORTHEAST WITH LAKE BREEZE DURING THE AFTERNOON. * CHANCE OF ISOLATED/SCATTERED TSRA MONDAY AFTERNOON. RATZER //DISCUSSION...UPDATED 00Z... AREA OF SURFACE LOW PRESSURE OVER THE LOWER MISSOURI VALLEY WILL CONTINUE TO TRACK SOUTHEAST INTO THE LOWER OHIO VALLEY TONIGHT. TO THE NORTH...A SERIES OF MINOR MID-LEVEL DISTURBANCES WILL RIPPLE ACROSS THE FORECAST AREA WITHIN THE ELEVATED FRONTAL ZONE NORTH OF THE SURFACE FRONT. THIS MAY SUPPORT A FEW SPOTTY SHOWERS ESPECIALLY FROM CHICAGO AND AREAS SOUTH AND EAST LATER THIS EVENING. AS MOIST LOW LEVELS COOL NOCTURNALLY...WILL LIKELY SEE DEVELOPMENT OF LOWER CLOUD DECKS/FOG...WHICH IS EXPECTED TO LOWER THROUGH MVFR INTO IFR LATER TONIGHT ESPECIALLY FOR ORD/MDW WHERE LIGHT WINDS EVENTUALLY BECOME MORE EAST/NORTHEAST OFF OF LAKE MICHIGAN. VARIOUS MODELS ARE FAIRLY INSISTENT IN IFR CONDITIONS...POSSIBLY EVEN LIFR...DEVELOPING BY THE PRE-DAWN HOURS...WITH IMPROVEMENT THEN BEGINNING AFTER SUNRISE. LIGHT GENERALLY SOUTH-SOUTHEAST WINDS SHOULD GRADUALLY SHIFT TO FROM SOUTHEAST TO THE NORTH-NORTHEAST THROUGH MONDAY MORNING. WINDS INLAND WILL TREND MORE NNW...THOUGH ORD/MDW/GYY WILL LIKELY MAINTAIN OR REDEVELOP A NE COMPONENT OFF OF THE LAKE IN THE AFTERNOON. ANOTHER UPPER DISTURBANCE AND ONLY SLOW DRYING IN THE LOW LEVELS MAY SUPPORT ISOLATED-SCATTERED TSRA FOR A PERIOD MONDAY AFTERNOON...POSSIBLY ALONG LAKE BREEZE BOUNDARY. RATZER //ORD AND MDW CONFIDENCE...UPDATED 00Z... * MEDIUM-HIGH IN WINDS. * MEDIUM IN CIG/VIS TRENDS TONIGHT/EARLY MONDAY. * MEDIUM-LOW IN MONDAY AFTERNOON TSRA. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY AND WEDNESDAY...VFR. NORTH-NORTHEAST WINDS. THURSDAY...VFR. SLIGHT CHANCE TSRA THURSDAY NGT. WEST-SOUTHWEST WINDS. FRIDAY...CHANCE TSRA. WEST-SOUTHWEST WINDS. SATURDAY...VFR. NORTHEAST WINDS. RATZER && .MARINE... 251 PM...LOW PRESSURE OVER NORTHERN ONTARIO WILL MOVE INTO QUEBEC BY MONDAY EVENING. A TRAILING COLD FRONT WILL MOVE ACROSS THE LAKE LATE TONIGHT INTO MONDAY MORNING SHIFTING WINDS NORTHERLY. ANOTHER WEAK LOW WILL MOVE SOUTH OF THE LAKE MONDAY AFTERNOON AS HIGH PRESSURE BUILDS INTO THE NORTHERN PLAINS. THE GRADIENT WILL TIGHTEN BETWEEN THESE TWO FEATURES WITH NORTHERLY WINDS INCREASING TO 15-25 KTS BY TUESDAY MORNING. AS THE HIGH MOVES EAST...THESE NORTHERLY WINDS WILL SLOWLY DIMINISH TUESDAY NIGHT INTO WEDNESDAY. WINDS WILL SHIFT TO THE SOUTHWEST WEDNESDAY NIGHT AS THE HIGH SETTLES SOUTHEAST OF THE LAKE AND DEPENDING ON HOW STRONG THE GRADIENT BECOMES...SPEEDS MAY INCREASE INTO THE 15-25KT RANGE THURSDAY INTO THURSDAY NIGHT. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
601 PM CDT SUN AUG 9 2015 .SHORT TERM...(TONIGHT) ISSUED AT 253 PM CDT SUN AUG 9 2015 BASED ON SURFACE DATA...APPEARS THERE IS A BOUNDARY STRETCHING FROM NORTHERN MO/SOUTHERN IA INTO NORTHERN PART OF CENTRAL IL. HOWEVER...THE EFFECTIVE BOUNDARY SHOULD BE MUCH FURTHER SOUTH AS A RESULT OF THE MCS THAT MOVED ACROSS THE AREA EARLIER THIS MORNING PUSHING IT SOUTH OF THE CWA. HRRR DOES NOT SHOW ANY PCPN IN THE CWA TONIGHT...BUT DOES HAVE THE SMALL AREA OF PCPN IN NORTHERN MO MOVING EAST-SOUTHEAST INTO SOUTHERN IL THIS EVENING. BUT WITH A WEAK CONVERGENT BOUNDARY IN THE AREA AM INCLINED TO KEEP A CHANCE FOR POPS IN THE FORECAST FOR TONIGHT. TREND SHOULD BE...AND MODELS DO SUPPORT THAT THIS WEAK BOUNDARY SHOULD MOVE SOUTH DURING THE OVERNIGHT PERIOD. SO CHANCE POPS SOUTHEAST OF THE ILLINOIS RIVER TONIGHT. ENDING OF PCPN CHANCES WILL START ALONG THE RIVER AND THEN PROGRESS SOUTHEAST THROUGH THE PERIOD. OTHER ISSUE OVERNIGHT WILL BE FOG DEVELOPMENT. WITH LOTS OF BREAKS IN THE CLOUDS THIS EVENING AND OVERNIGHT...COMBINED WITH THE ABUNDANCE OF LOW LEVEL MOISTURE FROM THE RAIN THIS MORNING...AND LIGHT WINDS...BELIEVE FOG WILL DEVELOP THIS EVENING AND CONTINUE INTO THE OVERNIGHT HOURS. SO HAVE INCLUDED AREAS OF FOG IN THE FORECAST THE NORTHERN AND CENTRAL PARTS OF THE AREA. ONLY PLACE WITHOUT ANY FOG WILL BE AREAS SOUTHEAST OF I-70. OVERNIGHT LOWS AROUND 70S LOOKS REASONABLE WITH COOLEST TEMPS UP NORTH WHERE MORE BREAKS IN CLOUDS SHOULD BE. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 253 PM CDT SUN AUG 9 2015 A FRONTAL BOUNDARY CURRENTLY FROM NORTHERN WISCONSIN TO NORTHERN NEBRASKA WILL PUSH INTO SOUTHEAST ILLINOIS BY MID MORNING MONDAY...AIDED BY SEVERAL AREAS OF THUNDERSTORM DEVELOPMENT AHEAD OF THE FRONT THIS EVENING INTO TONIGHT. THE EFFECTIVE FRONT WILL LIKELY BE LINGERING IN SOUTHEAST PORTIONS OF THE CENTRAL IL FORECAST AREA THROUGH THE MORNING AND HAVE CONTINUED PRECIPITATION CHANCES IN THAT AREA THROUGH NOON. MOST OF THE THUNDERSTORM ACTIVITY WILL TEND TO MOVE EASTWARD THROUGH THE DAY...HOWEVER AN UPPER LEVEL SHORTWAVE WILL APPROACH FROM THE NORTHWEST BY AFTERNOON...AND LIFT ASSOCIATED WITH THIS FEATURE WILL CAUSE CHANCES FOR SHOWERS AND THUNDERSTORMS TO RE-DEVELOP FOR AFTERNOON AND EARLY EVENING...MAINLY FROM THE ILLINOIS RIVER NORTHWESTWARD. HIGHS EXPECTED TO REACH FROM AROUND 81 IN GALESBURG TO THE MID 80S SPRINGFIELD TO PARIS SOUTHWARD WITH WINDS BECOMING NORTHWEST UP TO 10 MPH. AFTER THIS FEATURE PASSES THROUGH...DRY CONDITIONS ARE EXPECTED THROUGH MUCH OF THE WEEK AS A PRONOUNCED UPPER LEVEL RIDGE BUILDS OVER THE CENTRAL U.S. AND TROUGHING OVER THE NORTHEASTERN U.S. A COOL NORTHWEST FLOW PATTERN BETWEEN THE RIDGE AND TROUGH WILL BRING HIGH TEMPERATURES PRIMARILY IN THE LOW 80S AND LOWS IN THE LOW 60S THROUGH THURSDAY. A COLD FRONT EMBEDDED IN THIS FLOW PATTERN WILL DROP INTO THE GREAT LAKES/MIDWEST AREA FRIDAY. MODELS CONTINUE SOME RUN TO RUN INCONSISTENCIES FOR THIS FEATURE...BUT BULK OF GUIDANCE CONTINUES TO SUGGEST PRECIPITATION ASSOCIATED WITH THIS FEATURE MAY STRUGGLE TO REACH AS FAR SOUTHWEST AS CENTRAL ILLINOIS. THEREFORE...HAVE INCORPORATED SLIGHT CHANCES FOR THUNDERSTORMS MAINLY I-72 NORTHWARD. DRY CONDITIONS SHOULD THEN RETURN THROUGH THE WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 600 PM CDT SUN AUG 9 2015 MAIN CONCERN THIS PERIOD WILL BE WITH COVERAGE OF ANY CONVECTION THAT MAY REDEVELOP...ESPECIALLY AT SPI AND DEC...AND THE FOG AND STRATUS THREAT LATER TONIGHT. BOUNDARY LEFT OVER FROM THE MORNING CONVECTION HAS SLIPPED SOUTH OF THE TAF SITES AND APPEARS THAT IT WILL BE THE PRIMARY FOCUS FOR SHOWERS AND STORMS TONIGHT. A SECOND FRONT WELL TO OUR NORTHWEST WILL PUSH INTO OUR AREA MONDAY MORNING. WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE THIS EVENING AT SPI AND DEC WITH THE PRIMARY THREAT FOR STORMS SHIFTING SOUTH OF I72 CLOSER TO I-70 BY LATE EVENING. THEN THE FOCUS SHIFTS TOWARDS FOG AS ABUNDANT LOW LEVEL MOISTURE FROM THIS MORNING`S RAIN COMBINED WITH A LIGHT WIND FLOW WILL BRING ABOUT LOW CIGS AND VSBYS LATE TONIGHT INTO MONDAY MORNING. MOST OF THE FORECAST MODELS BRING CIGS DOWN TO MVFR WITH SOME TEMPO IFR CIGS AND VSBYS IN STRATUS AND FOG EARLY MONDAY MORNING SO WILL CONTINUE FROM PREVIOUS TRENDS IN BRINGING THE VSBYS AND CIGS DOWN AFTER 03Z. WHAT FOG/STRATUS WE DO SEE OVERNIGHT SHOULD DISSIPATE BY 13Z WITH SOME SCT-BKN CUMULUS FROM 2500-3500 FEET. SURFACE WINDS SHOULD BE LIGHT AND VARIABLE TONIGHT AND THEN BECOME NORTHWEST TO NORTH AT 10 TO 15 KTS BY AFTERNOON. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...AUTEN LONG TERM...ONTON AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
516 PM CDT SAT AUG 8 2015 .SHORT TERM... 320 PM CDT THROUGH SUNDAY... MAIN CONCERN IS WITH CONVECTIVE POTENTIAL LATE TONIGHT INTO SUNDAY. RAOBS AND AIRCRAFT SOUNDINGS TODAY SHOWED AN ENVIRONMENT HOSTILE TO PRECIP MAINTENANCE. THEREFORE DESPITE SOME FORCING FROM A CONVECTIVELY INDUCED SHORTWAVE OVERHEAD...LIGHT RADAR ECHOES OVER AREA ARE LIKELY VIRGA AND HAVE PULLED MENTION OF SPRINKLES THE REST OF TODAY. CONVERGENT AXIS IN FRONTAL ZONE OF DISSIPATING WEAK LOW OVER SOUTHERN LAKE MICHIGAN DID INITIATIVE SOME CONVECTION OVER NORTH CENTRAL INDIANA...AND WOULD EXPECT FURTHER DEVELOPMENT TO REMAIN EAST OF THE CWA. OVERALL...WITH PLENTY OF CLOUD COVER WELL BACK TO THE WEST...INCLUDING PATCHY LOWER CLOUDS IN SPOTS...JUST EXPECTING A MOSTLY CLOUDY REST OF THE DAY INTO TONIGHT. VERY WEAK GRADIENT WILL YIELD LIGHT/CALM WINDS OVERNIGHT AND LOW DEWPOINT SPREADS COULD SET STAGE FOR SOME PATCHY FOG OR HAZE. LOW TEMPS WILL BE IN THE MID 60S TO AROUND 70. FOCUS LATE TONIGHT INTO SUNDAY WILL BE ON MCS EXPECTED TO DEVELOP OVER EASTERN NEBRASKA AND WESTERN IOWA THIS EVENING. MCS IS LIKELY TO RIDE ALONG INSTABILITY AXIS THAT WILL MAINLY BE SOUTH OF THE CWA OFF TO THE EAST-SOUTHEAST INTO SUNDAY MORNING. CONSENSUS OF MODEL GUIDANCE IS TO KEEP INSTABILITY MINIMAL AT BEST FOR MUCH OF THE CWA...LIMITING THUNDER POTENTIAL. CANNOT COMPLETELY RULE OUT THUNDER GIVEN MODEST LOW LEVEL JET/WAA REGIME. RECENT HI-RES CAMS...INCLUDING 4KM NAM AND EXPERIMENTAL HRRR DEPICT A REASONABLE SCENARIO IN WHICH STRATIFORM NORTH OF MCS OVERSPREADS MUCH OF CWA FROM WESTNORTHWEST TO EAST SOUTHEAST AFTER MIDNIGHT THROUGH MID SUNDAY MORNING/BY WHICH TIME IT WILL PROBABLY BE DECAYING. HAVE FOCUSED CATEGORICAL POPS INTO SOUTHERN CWA WHERE CONFIDENCE IS HIGHEST IN WIDESPREAD COVERAGE. ITS POSSIBLE FAR NORTHEAST CWA COULD SEE LITTLE OR NO RAIN. BEST CHANCE FOR HEAVY DOWNPOURS LOOKS TO BE IN FAR SOUTHERN CWA WHERE MORE ROBUST CONVECTION COULD PASS THROUGH...THOUGH ANY THREAT FOR STRONG TO SEVERE STORMS SHOULD STAY SOUTHWEST OF THE CWA GIVEN ANTICIPATED DECAYING TREND OF MCS. A GOOD DEAL OF UNCERTAINTY THE REMAINDER OF SUNDAY REGARDING CONVECTIVE TRENDS. A SURFACE LOW LOOKS TO EVOLVE EASTWARD INTO THE MID MISSISSIPPI VALLEY BY LATER IN THE DAY...WITH RETURN FLOW AND WEST-SOUTHWEST LLJ ALSO DEVELOPING. LINGERING CLOUD COVER WILL LIMIT DESTABILIZATION AND THUNDER POTENTIAL...ESPECIALLY FARTHER NORTH UNTIL LATE DAY. ANOTHER SHORTWAVE WILL APPROACH FROM WEST IN LATE AFTERNOON AND THERE SHOULD BE ENOUGH 925-850 MB MOISTURE CONVERGENCE TO SUPPORT CHANCE POPS NORTH OF I-80 AND LIKELIESSOUTH OF I-80. MODERATE WESTERLY MIDLEVEL FLOW WILL RESULT IN 30-40 KT OF WEST-NORTHWEST 0-6KM SHEAR. THIS WILL SUPPORT SOME THREAT FOR STRONG TO SEVERE STORMS WELL SOUTH OF I-80 CLOSER TO EXPECTED TRACK OF SFC LOW AND WHERE TEMPS AROUND 80 AND LOW-MID 70S DEWPOINTS COULD BRING SLIGHTLY BETTER INSTABILITY. MAIN THREAT WOULD BE GUSTY TO DAMAGING WINDS...AS HAIL APPEARS UNLIKELY WITH 700-500 MB LAPSE RATES LESS THAN 6 CELSIUS PER KM. SUNDAY OVERALL WILL BE A CLOUDY AND MUGGY DAY...WITH HIGHS IN THE MID 70S TO AROUND 80. RC && .LONG TERM... 320 PM CDT SUNDAY NIGHT THROUGH SATURDAY... THE BEST CHANCE FOR PRECIP IN THE EXTENDED WILL BE SUNDAY EVENING THROUGH MONDAY AFTERNOON...WITH VERY SLIGHT CHANCES OF PRECIP LATE NEXT WEEK. A COMPLEX OF STORMS WILL BE DIMINISHING OVER THE REGION SUNDAY EVENING AND NIGHT. THE UPPER LEVEL VORTICITY PATTERN IS VERY CHAOTIC WITH GUIDANCE INDICATING THE MAIN MCV WILL BE OVER CENTRAL IL AND VORT STREAMERS ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE OVER WISCONSIN. WITH SUCH A MESSY PATTERN...DECIDED TO ONLY MAKE MINOR ADJUSTMENTS TO PRECIP CHANCES SUNDAY NIGHT. HAVE A CHANCE OF THUNDERSTORMS ALONG AND EAST OF I-39 WITH BETTER CHANCES EAST OF I- 55. COULD SEE A FEW STRONG TO SEVERE STORMS SOUTH OF I-80 BUT CONDITIONS WILL BE WEAKENING AS THE EVENING PROGRESSES. OVERALL...HAVE LOW CONFIDENCE IN EXACTLY HOW SUNDAY NIGHT WILL PLAY OUT DUE TO SO MANY MESOSCALE FEATURES AND WHETHER OR NOT THE ATMOSPHERE WILL BE ABLE TO RECOVER FROM SUNDAY MORNING/S STORMS. A SHORT WAVE MOVING WITH THE UPPER LEVEL TROUGH ROTATES THROUGH MONDAY WITH A DECENT VORTICITY STREAMER. WENT WITH A CHANCE OF SHOWERS AND STORMS MAINLY NORTH OF I-80 MONDAY. THINKING THE NAM IS ONCE AGAIN TOO MOIST LEADING TO TOO MUCH CONVECTIVE DEVELOPMENT. THINKING SHOWERS AND STORMS WILL DRIFT SOUTH OF THE IL/WI STATE LINE MONDAY AFTERNOON AND THEN WEAKEN AS THEY CONTINUE TO SHIFT SOUTH MONDAY EVENING. MONDAY EVENING MAY END UP BEING DRY...BUT DID NOT HAVE ENOUGH CONFIDENCE IN A DRY FORECAST SO KEPT A SLIGHT CHANCE OF SHOWERS AND STORMS ALONG AND SOUTH OF I-80 MONDAY EVENING. THE UPPER LEVEL TROUGH AXIS SHIFTS EAST THROUGH WISCONSIN WITH COOLER UPPER LEVEL AIR SINKING SOUTH THROUGH THE REGION. HIGH PRESSURE THEN BUILDS IN FOR WEDNESDAY AND THURSDAY LEADING TO DRY CONDITIONS THROUGH THURSDAY. HIGH TEMPS TUESDAY WILL BE AROUND 80...THEN IN THE UPPER 70S WEDNESDAY. LAKE BREEZES BOTH DAYS WILL KEEP LOCATIONS ALONG THE LAKE IN THE MID 70S. TEMPS REBOUND INTO THE LOW TO MID 80S THURSDAY WITH NO LAKE COOLING. THE NEXT LOW PRESSURE SYSTEM MOVES OVER JAMES BAY THURSDAY EVENING AND PUSHES THE HIGH PRESSURE SOUTH OVER THE OHIO VALLEY. THE LOWS COLD FRONT SINKS SOUTH OVER FAR NORTHERN IL FRIDAY AFTERNOON SO HAVE A SLIGHT CHANCE TO CHANCE OF SHOWERS AND STORMS. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * WIND SHIFT TO NE AT ORD EXPECTED BY 00Z...PREVAILING SPEED ANTICIPATED TO BE NEAR BUT JUST UNDER 10 KTS. * MVFR CEILINGS IN FOG AND RAIN SUNDAY MORNING AND DAYTIME. * ISOLATED THUNDERSTORM CHANCE SUNDAY. MM/RATZER //DISCUSSION...UPDATED 22Z... LAKE BREEZE PUSHED INLAND SOUTH OF ORD...THOUGH COMPLEX NATURE OF SFC PRESSURE GRADIENT ASSOCIATED WITH WEAK LOW MOVING SOUTHEAST ACROSS LAKE MICHIGAN HAS HELD LAKE BREEZE EAST OF ORD THROUGH LATE AFTERNOON. THIS WILL CHANGE NEXT 1-2 HOURS AS LARGER SCALE FLOW PATTERN WHICH WAS SHIFTING TO THE NORTH...FLIPS OVER TO THE NORTHEAST. WIND HAS SHIFTED AT KUGN...AND CAN BEGIN TO SEE BOUNDARY MOVING SOUTHWEST IN TORD TDWR REFLECTIVITY OVER SOUTHEAST LAKE CO IL. EXTRAPOLATION OF THIS FEATURE SUGGEST 2330-0000Z SHIFT TO NORTHEAST FOR ORD. AS WITH MANY LAKE BREEZE/DENSITY CURRENTS... SPEED MAY FLIRT WITH THE 10-15 KT RANGE BRIEFLY...THOUGH FORECAST SOUNDINGS DEPICT WINDS LESS THAN 10 KTS THROUGH MIXED LAYER AND EXPECTATION IS THAT PREVAILING WIND SPEED WILL BE JUST UNDER 10 KTS. RATZER PREVIOUS DISCUSSION FROM 18Z... SURFACE ANALYSIS INDICATES A WEAK LOW AND ASSOCIATED TROUGH/BOUNDARY WITHIN THE DOMINANT HIGH OVER MUCH OF THE GREAT LAKES. THIS HAS CAUSED THE WIND FIELD TO BECOME QUITE CONVOLUTED WITH A MESO- CYCLONE CENTERED NORTH OF CHICAGO. RADAR IMAGERY DOES INDICATE A LAKE BREEZE PROGGED TO REACH ORD/MDW AROUND 19-20Z. TIMING MAY NEED ADJUSTING IF THE BOUNDARY STALLS BETWEEN THE SHORE AND ORD...BUT AT THIS PACE WINDS SHOULD BE NORTHEAST AT 20Z. A MORE SUBSTANTIAL LOW WILL APPROACH INTO SUNDAY WITH MOISTURE CONTENT ON THE RISE THROUGH TONIGHT. FORECAST SOUNDINGS INDICATE A LOW LEVEL INVERSION FROM 09-13Z. SURFACE MOISTURE IS ADEQUATE ENOUGH TO ALLOW FOR SOME FOG...FOLLOWED BY THE ARRIVAL OF RAIN SUNDAY MORNING. RAIN/SHOWERY CONDITIONS ARE EXPECTED TO PERSIST MUCH OF THE DAY AND THERE WILL MAY ALSO BE A PERIOD OF THUNDER AS WELL. TIMING OF THUNDER IS UNDER QUESTION AS THE INITIAL ARRIVAL OF THE LOW MAY SUPPORT A BRIEF UPTICK IN LAPSE RATES...OTHERWISE WILL HAVE TO WAIT FOR ADDL SFC HEATING AFTER 20Z SUNDAY. MM //ORD AND MDW CONFIDENCE...UPDATED 22Z... * MEDIUM-HIGH IN WINDS * MEDIUM IN MVFR FOG...MEDIUM HIGH IN RAIN. * LOW IN THUNDER AND TIMING. MM/RATZER //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE OF THUNDERSTORMS. MONDAY...CHANCE OF THUNDERSTORMS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...SLIGHT CHANCE OF SHOWERS LATE. FRIDAY...VFR. RODRIGUEZ && .MARINE... 320 PM CDT HIGH PRESSURE STRETCHES FROM QUEBEC THROUGH THE OHIO VALLEY WHILE LOW PRESSURE IS OVER MANITOBA. BOTH SYSTEMS WILL SHIFT EAST WITH THE LOW REACHING JAMES BAY BY MONDAY MORNING. AS SUCH LIGHT NORTHEAST WINDS BECOME SOUTH TO SOUTHEAST SUNDAY. THE TROUGH ASSOCIATED WITH THE LOWS COLD/STATIONARY FRONT SHIFTS THROUGH LATE SUNDAY NIGHT INTO MONDAY MORNING WITH WINDS BECOMING NORTH BEHIND IT. A WEAK CLOSED LOW FORMS OVER THE EASTERN GREAT LAKES MONDAY EVENING AND DEEPENS AS IT SHIFTS NORTHEAST. AT THE SAME TIME HIGH PRESSURE WILL BE PUSHING EAST OVER THE WESTERN GREAT LAKES. THIS WILL LEAD TO NORTH WINDS INCREASING TO 10 TO 20 KT MONDAY NIGHT THROUGH TUESDAY NIGHT. WINDS WEAKEN WEDNESDAY WITH THE HIGH OVERHEAD...AND THEN BACK TO SOUTHWEST AS THE HIGH IS PUSHED SOUTH BY THE NEXT LOW OVER JAMES BAY THURSDAY. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
321 PM CDT SAT AUG 8 2015 .SHORT TERM... 320 PM CDT THROUGH SUNDAY... MAIN CONCERN IS WITH CONVECTIVE POTENTIAL LATE TONIGHT INTO SUNDAY. RAOBS AND AIRCRAFT SOUNDINGS TODAY SHOWED AN ENVIRONMENT HOSTILE TO PRECIP MAINTENANCE. THEREFORE DESPITE SOME FORCING FROM A CONVECTIVELY INDUCED SHORTWAVE OVERHEAD...LIGHT RADAR ECHOES OVER AREA ARE LIKELY VIRGA AND HAVE PULLED MENTION OF SPRINKLES THE REST OF TODAY. CONVERGENT AXIS IN FRONTAL ZONE OF DISSIPATING WEAK LOW OVER SOUTHERN LAKE MICHIGAN DID INITIATIVE SOME CONVECTION OVER NORTH CENTRAL INDIANA...AND WOULD EXPECT FURTHER DEVELOPMENT TO REMAIN EAST OF THE CWA. OVERALL...WITH PLENTY OF CLOUD COVER WELL BACK TO THE WEST...INCLUDING PATCHY LOWER CLOUDS IN SPOTS...JUST EXPECTING A MOSTLY CLOUDY REST OF THE DAY INTO TONIGHT. VERY WEAK GRADIENT WILL YIELD LIGHT/CALM WINDS OVERNIGHT AND LOW DEWPOINT SPREADS COULD SET STAGE FOR SOME PATCHY FOG OR HAZE. LOW TEMPS WILL BE IN THE MID 60S TO AROUND 70. FOCUS LATE TONIGHT INTO SUNDAY WILL BE ON MCS EXPECTED TO DEVELOP OVER EASTERN NEBRASKA AND WESTERN IOWA THIS EVENING. MCS IS LIKELY TO RIDE ALONG INSTABILITY AXIS THAT WILL MAINLY BE SOUTH OF THE CWA OFF TO THE EAST-SOUTHEAST INTO SUNDAY MORNING. CONSENSUS OF MODEL GUIDANCE IS TO KEEP INSTABILITY MINIMAL AT BEST FOR MUCH OF THE CWA...LIMITING THUNDER POTENTIAL. CANNOT COMPLETELY RULE OUT THUNDER GIVEN MODEST LOW LEVEL JET/WAA REGIME. RECENT HI-RES CAMS...INCLUDING 4KM NAM AND EXPERIMENTAL HRRR DEPICT A REASONABLE SCENARIO IN WHICH STRATIFORM NORTH OF MCS OVERSPREADS MUCH OF CWA FROM WESTNORTHWEST TO EAST SOUTHEAST AFTER MIDNIGHT THROUGH MID SUNDAY MORNING/BY WHICH TIME IT WILL PROBABLY BE DECAYING. HAVE FOCUSED CATEGORICAL POPS INTO SOUTHERN CWA WHERE CONFIDENCE IS HIGHEST IN WIDESPREAD COVERAGE. ITS POSSIBLE FAR NORTHEAST CWA COULD SEE LITTLE OR NO RAIN. BEST CHANCE FOR HEAVY DOWNPOURS LOOKS TO BE IN FAR SOUTHERN CWA WHERE MORE ROBUST CONVECTION COULD PASS THROUGH...THOUGH ANY THREAT FOR STRONG TO SEVERE STORMS SHOULD STAY SOUTHWEST OF THE CWA GIVEN ANTICIPATED DECAYING TREND OF MCS. A GOOD DEAL OF UNCERTAINTY THE REMAINDER OF SUNDAY REGARDING CONVECTIVE TRENDS. A SURFACE LOW LOOKS TO EVOLVE EASTWARD INTO THE MID MISSISSIPPI VALLEY BY LATER IN THE DAY...WITH RETURN FLOW AND WEST-SOUTHWEST LLJ ALSO DEVELOPING. LINGERING CLOUD COVER WILL LIMIT DESTABILIZATION AND THUNDER POTENTIAL...ESPECIALLY FARTHER NORTH UNTIL LATE DAY. ANOTHER SHORTWAVE WILL APPROACH FROM WEST IN LATE AFTERNOON AND THERE SHOULD BE ENOUGH 925-850 MB MOISTURE CONVERGENCE TO SUPPORT CHANCE POPS NORTH OF I-80 AND LIKELIKES SOUTH OF I-80. MODERATE WESTERLY MIDLEVEL FLOW WILL RESULT IN 30-40 KT OF WEST-NORTHWEST 0-6KM SHEAR. THIS WILL SUPPORT SOME THREAT FOR STRONG TO SEVERE STORMS WELL SOUTH OF I-80 CLOSER TO EXPECTED TRACK OF SFC LOW AND WHERE TEMPS AROUND 80 AND LOW-MID 70S DEWPOINTS COULD BRING SLIGHTLY BETTER INSTABILITY. MAIN THREAT WOULD BE GUSTY TO DAMAGING WINDS...AS HAIL APPEARS UNLIKELY WITH 700-500 MB LAPSE RATES LESS THAN 6 CELSIUS PER KM. SUNDAY OVERALL WILL BE A CLOUDY AND MUGGY DAY...WITH HIGHS IN THE MID 70S TO AROUND 80. RC && .LONG TERM... 320 PM CDT SUNDAY NIGHT THROUGH SATURDAY... THE BEST CHANCE FOR PRECIP IN THE EXTENDED WILL BE SUNDAY EVENING THROUGH MONDAY AFTERNOON...WITH VERY SLIGHT CHANCES OF PRECIP LATE NEXT WEEK. A COMPLEX OF STORMS WILL BE DIMINISHING OVER THE REGION SUNDAY EVENING AND NIGHT. THE UPPER LEVEL VORTICITY PATTERN IS VERY CHAOTIC WITH GUIDANCE INDICATING THE MAIN MCV WILL BE OVER CENTRAL IL AND VORT STREAMERS ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE OVER WISCONSIN. WITH SUCH A MESSY PATTERN...DECIDED TO ONLY MAKE MINOR ADJUSTMENTS TO PRECIP CHANCES SUNDAY NIGHT. HAVE A CHANCE OF THUNDERSTORMS ALONG AND EAST OF I-39 WITH BETTER CHANCES EAST OF I- 55. COULD SEE A FEW STRONG TO SEVERE STORMS SOUTH OF I-80 BUT CONDITIONS WILL BE WEAKENING AS THE EVENING PROGRESSES. OVERALL...HAVE LOW CONFIDENCE IN EXACTLY HOW SUNDAY NIGHT WILL PLAY OUT DUE TO SO MANY MESOSCALE FEATURES AND WHETHER OR NOT THE ATMOSPHERE WILL BE ABLE TO RECOVER FROM SUNDAY MORNING/S STORMS. A SHORT WAVE MOVING WITH THE UPPER LEVEL TROUGH ROTATES THROUGH MONDAY WITH A DECENT VORTICITY STREAMER. WENT WITH A CHANCE OF SHOWERS AND STORMS MAINLY NORTH OF I-80 MONDAY. THINKING THE NAM IS ONCE AGAIN TOO MOIST LEADING TO TOO MUCH CONVECTIVE DEVELOPMENT. THINKING SHOWERS AND STORMS WILL DRIFT SOUTH OF THE IL/WI STATE LINE MONDAY AFTERNOON AND THEN WEAKEN AS THEY CONTINUE TO SHIFT SOUTH MONDAY EVENING. MONDAY EVENING MAY END UP BEING DRY...BUT DID NOT HAVE ENOUGH CONFIDENCE IN A DRY FORECAST SO KEPT A SLIGHT CHANCE OF SHOWERS AND STORMS ALONG AND SOUTH OF I-80 MONDAY EVENING. THE UPPER LEVEL TROUGH AXIS SHIFTS EAST THROUGH WISCONSIN WITH COOLER UPPER LEVEL AIR SINKING SOUTH THROUGH THE REGION. HIGH PRESSURE THEN BUILDS IN FOR WEDNESDAY AND THURSDAY LEADING TO DRY CONDITIONS THROUGH THURSDAY. HIGH TEMPS TUESDAY WILL BE AROUND 80...THEN IN THE UPPER 70S WEDNESDAY. LAKE BREEZES BOTH DAYS WILL KEEP LOCATIONS ALONG THE LAKE IN THE MID 70S. TEMPS REBOUND INTO THE LOW TO MID 80S THURSDAY WITH NO LAKE COOLING. THE NEXT LOW PRESSURE SYSTEM MOVES OVER JAMES BAY THURSDAY EVENING AND PUSHES THE HIGH PRESSURE SOUTH OVER THE OHIO VALLEY. THE LOWS COLD FRONT SINKS SOUTH OVER FAR NORTHERN IL FRIDAY AFTERNOON SO HAVE A SLIGHT CHANCE TO CHANCE OF SHOWERS AND STORMS. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LAKE BREEZE APPROACHING ORD AT 22Z. * MVFR CEILINGS IN FOG AND RAIN SUNDAY MORNING AND DAYTIME. * ISOLATED THUNDERSTORM CHANCE. MM //DISCUSSION...UPDATED 18Z... SURFACE ANALYSIS INDICATES A WEAK LOW AND ASSOCIATED TROUGH/BOUNDARY WITHIN THE DOMINANT HIGH OVER MUCH OF THE GREAT LAKES. THIS HAS CAUSED THE WIND FIELD TO BECOME QUITE CONVOLUTED WITH A MESO-CYCLONE CENTERED NORTH OF CHICAGO. RADAR IMAGERY DOES INDICATE A LAKE BREEZE PROGGED TO REACH ORD/MDW AROUND 19-20Z. TIMING MAY NEED ADJUSTING IF THE BOUNDARY STALLS BETWEEN THE SHORE AND ORD...BUT AT THIS PACE WINDS SHOULD BE NORTHEAST AT 20Z. A MORE SUBSTANTIAL LOW WILL APPROACH INTO SUNDAY WITH MOISTURE CONTENT ON THE RISE THROUGH TONIGHT. FORECAST SOUNDINGS INDICATE A LOW LEVEL INVERSION FROM 09-13Z. SURFACE MOISTURE IS ADEQUATE ENOUGH TO ALLOW FOR SOME FOG...FOLLOWED BY THE ARRIVAL OF RAIN SUNDAY MORNING. RAIN/SHOWERY CONDITIONS ARE EXPECTED TO PERSIST MUCH OF THE DAY AND THERE WILL MAY ALSO BE A PERIOD OF THUNDER AS WELL. TIMING OF THUNDER IS UNDER QUESTION AS THE INITIAL ARRIVAL OF THE LOW MAY SUPPORT A BRIEF UPTICK IN LAPSE RATES...OTHERWISE WILL HAVE TO WAIT FOR ADDL SFC HEATING AFTER 20Z SUNDAY. MM //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM IN WINDS..LOW IN ORD LAKE BREEZE. * MEDIUM IN MVFR FOG...MEDIUM HIGH IN RAIN. * LOW IN THUNDER AND TIMING. MM //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE OF THUNDERSTORMS. MONDAY...CHANCE OF THUNDERSTORMS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...SLIGHT CHANCE OF SHOWERS LATE. FRIDAY...VFR. RODRIGUEZ && .MARINE... 320 PM CDT HIGH PRESSURE STRETCHES FROM QUEBEC THROUGH THE OHIO VALLEY WHILE LOW PRESSURE IS OVER MANITOBA. BOTH SYSTEMS WILL SHIFT EAST WITH THE LOW REACHING JAMES BAY BY MONDAY MORNING. AS SUCH LIGHT NORTHEAST WINDS BECOME SOUTH TO SOUTHEAST SUNDAY. THE TROUGH ASSOCIATED WITH THE LOWS COLD/STATIONARY FRONT SHIFTS THROUGH LATE SUNDAY NIGHT INTO MONDAY MORNING WITH WINDS BECOMING NORTH BEHIND IT. A WEAK CLOSED LOW FORMS OVER THE EASTERN GREAT LAKES MONDAY EVENING AND DEEPENS AS IT SHIFTS NORTHEAST. AT THE SAME TIME HIGH PRESSURE WILL BE PUSHING EAST OVER THE WESTERN GREAT LAKES. THIS WILL LEAD TO NORTH WINDS INCREASING TO 10 TO 20 KT MONDAY NIGHT THROUGH TUESDAY NIGHT. WINDS WEAKEN WEDNESDAY WITH THE HIGH OVERHEAD...AND THEN BACK TO SOUTHWEST AS THE HIGH IS PUSHED SOUTH BY THE NEXT LOW OVER JAMES BAY THURSDAY. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
309 PM CDT SAT AUG 8 2015 .SHORT TERM...(TONIGHT) ISSUED AT 307 PM CDT SAT AUG 8 2015 REMNANTS OF AN MCS OVER EASTERN MO AT MID AFTERNOON HAS ISOLATED LIGHT SHOWERS AND SPRINKLES OVER CENTRAL IL WEST OF I-57 AND DRIFTING EASTWARD. MOST OF OUR AREA SHOULD STAY DRY INTO THIS EVENING WITH JUST A FEW LIGHT SHOWERS OR SPRINKLES POSSIBLE OVER PARTS OF CENTRAL IL WITH PARTLY TO MOSTLY CLOUDY SKIES. ANOTHER MCS WILL LIKELY DEVELOP OVER WESTERN IA AND FAR EASTERN NEBRASKA ON NOSE OF AN 35-45 KT 850 MB SW JET THIS EVENING AND TRACK ESE ACROSS IA AND EVENTUALLY INTO CENTRAL IL DURING OVERNIGHT. 4KM WRF AND TAIL END OF HRRR MODEL SHOWS MOST OF CONVECTION SREADING EAST TOWARD IL RIVER VALLEY BETWEEN 08Z-10Z AND APPROACHING I-57 AROUND 12Z. CONTINUED MENTION OF HEAVY RAIN FROM PEORIA NW LATE TONIGHT AFTER 09Z/4 AM WITH QPF OVERNIGHT HALF TO THREE QUARTER INCHES AND LOCALLY 1 INCH FROM GALESBURG AND MACOMB WEST. SPC HAS MARGINAL RISK OF SEVERE STORMS OVERNIGHT WEST OF PEORIA AND SPRINGFIELD FOR GUSTY WINDS AND SMALL HAIL WHILE SLIGHT RISK OF SEVERE IS FROM QUINCY WESTWARD ACROSS NORTHERN MO AND SOUTHERN IA. SE IL/WABASH RIVER VALLEY WILL LIKELY STAY DRY MOST OF TONIGHT AND PATCHY FOG COULD FORM OVERNIGHT IN FAR SOUTHEAST IL WHERE LESS CLOUD COVER. MUGGY LOWS TONIGHT IN THE UPPER 60S AND LOWER 70S WHICH IS CLOSE TO CURRENT DEWPOINTS AND LIGHT WINDS TONIGHT. && .LONG TERM...(SUNDAY THROUGH SATURDAY) ISSUED AT 307 PM CDT SAT AUG 8 2015 A THUNDERSTORM COMPLEX/MCS IS EXPECTED TO TRACK EASTWARD ACROSS ILLINOIS SUNDAY MORNING...LIKELY WEAKENING THROUGH THE DAYTIME. ALTHOUGH STILL WAITING FOR THIS SYSTEM TO DEVELOP AROUND EASTERN NB/WESTERN IA THIS EVENING...RECENT TRENDS HAVE BEEN FOR SIMILAR SYSTEMS TO DEVELOP SLIGHTLY SOUTHWARD FROM EARLY FORECASTS...AND LATEST MODEL RUNS HINT AT THIS AS WELL. THEREFORE...HAVE TRENDED HEAVIER PRECIPITATION AMOUNTS A BIT SOUTHWARD FROM PREVIOUS PACKAGE WITH AMOUNTS FROM AROUND 1 TO 1.5 INCHES POSSIBLE NORTH OF I-72 AND WEST OF I-55 BY NOON SUNDAY...WITH THE HIGHER END OF THAT RANGE MORE LIKELY TOWARD THE GALESBURG AREA. LOWER AMOUNTS AND LOWER PRECIPITATION CHANCES EXPECTED WITH THIS SYSTEM SOUTH OF I-72 TOWARD THE EFFINGHAM/I-70 AREA. A BIT OF A BREAK IN THUNDERSTORM ACTIVITY LIKELY FOR MIDDAY SUNDAY AS THE OVERNIGHT SYSTEM MOVES OFF TO THE EAST. EXACT TIMING...CLOUD COVER LEFT BEHIND...AND BOUNDARIES LEFT BEHIND FROM THE OVERNIGHT SYSTEM WILL IMPACT THE POSSIBILITY OF ANOTHER THUNDERSTORM COMPLEX DEVELOPING SUNDAY NIGHT. CURRENT MODEL CONSENSUS FORMS THIS FARTHER SOUTH TOWARD THE OHIO VALLEY AREA AND HAVE TRENDED PRECIP CHANCES TOWARD THAT AREA FOR SUNDAY NIGHT INTO MONDAY. AFTER THAT...UPPER RIDGING WILL BUILD OVER THE CENTRAL CONUS AND DEEP TROUGHING WILL DEVELOP DOWNSTREAM ACROSS THE GREAT LAKES/OHIO RIVER VALLEY. AS A RESULT...MUCH OF THE EXTENDED BEYOND MONDAY IS COOL/DRY. GFS/ECMWF SHOW THE NEXT FRONTAL BOUNDARY DROPPING INTO THE GREAT LAKES AREA JUST NORTH OF CENTRAL IL FRIDAY. HOWEVER...BOTH LARGELY DISSIPATE THE FEATURE AND WILL MENTION JUST A SLIGHT CHANCE POP ACROSS THE NORTHERN HALF OF THE CWA ON FRIDAY UNTIL BETTER MODEL CONSISTENCY IS ACHIEVED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1259 PM CDT SAT AUG 8 2015 WEAKENING MCS OVER CENTRAL MO WITH SCATTERED RAIN SHOWERS AS FAR EAST AS THE IL RIVER TO CONTINUE TO WEAKEN IS IT PUSHES EAST ACROSS CENTRAL IL THIS AFTERNOON. HAVE VCSH THIS AFTERNOON ALONG WITH SCATTERED CUMULUS CLOUDS AND BROKEN MID/HIGH CLOUDS. MEANWHILE A WEAK SURFACE TROF MOVING SE TOWARD DEC AND CMI EARLY THIS AFTERNOON COULD TRIGGER VERY ISOLATED CONVECTION THIS AFTERNOON ALONG WITH BROKEN MVFR CEILINGS 2-3K FT. ALSO SEEING A WIND SHIFT FROM SW DIRECTION TO WNW GENERALLY LESS THAN 10 KTS. ANOTHER MCS EXPECTED TO DEVELOP OVER IA THIS EVENING AND SPREAD SE INTO CENTRAL IL OVERNIGHT INTO SUNDAY MORNING. HAVE MVFR VSBYS 3-5 MILES AND CEILINGS FROM 2-4K FT POSSIBLE WITH CONVECTION AT PIA AT 08Z...NEAR I-55 AT BMI AND SPI BY 10Z AND CMI BY 12Z. CONVECTION MORE LIKELY ALONG I-74 LATER TONIGHT INTO SUNDAY MORNING AND EXPECTED TO DIMINISH LATE SUNDAY MORNING OR BY MIDDAY SUNDAY. SSE WINDS OF 5-10 KTS EXPECTED BY LATER SUNDAY MORNING. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...07 LONG TERM...ONTON AVIATION...07
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
251 PM CDT SAT AUG 8 2015 .UPDATE...1154 AM CDT 12Z RAOBS AND RECENT AMDAR SOUNDINGS SHOW A SIGNIFICANT WARM NOSE ABOVE 850 MB...AS WELL AS PLENTY OF DRY AIR BETWEEN 850 AND 700 MB. LIGHT STRATIFORM PRECIP REMNANTS ON NORTHERN EDGE OF EARLY MORNING MCS OVER IOWA HAS BEEN ERODING WITH EASTWARD EXTENT AS IT ENCOUNTERS HOSTILE ENVIRONMENT FOR PRECIP. SOME SCATTERED SPRINKLES COULD GET INTO PORTIONS OF WEST AND SOUTHWEST CWA THIS AFTERNOON AS THERE IS SOME FORCING FROM CONVECTIVELY INDUCED SHORTWAVE. HOWEVER WOULD NOT EXPECT ANY ORGANIZED RAIN TO SURVIVE INTO THE CWA. THE WARM NOSE ALOFT ALSO THROWS INTO DOUBT ANY ISOLATED CONVECTION BEING ABLE TO INITIATE IN SOUTHEAST CWA THIS AFTERNOON IN CONVERGENT AXIS OF DISSIPATING SURFACE LOW AND LAKE BREEZE EXPECTED TO MOVE INLAND. CONVECTIVE TEMPS IN MID 90S MAKE IT UNLIKELY THAT CAPE IS AS HIGH AS SHOWN ON SPC MESOANALYSIS...AS RAP INITIALIZATION HAS A HIGH BIAS WITH TEMPS. SOME CUMULUS HAS POPPED UP...BUT NOT APPEARING TOO AGITATED UNDER CIRRUS SHIELD. HAVE KEPT JUST SLIGHT CHANCE POPS IN SOUTHEAST 1/3 OF CWA THIS AFTERNOON. OTHERWISE...TEMPERATURES ARE EXHIBITING A NORTH TO SOUTH GRADIENT...DRIVEN BY LOWER STRATUS IN NORTHERN CWA KEEPING TEMPS IN 70S WHILE LOWER-MID 80S IN SOUTHEAST 1/2 OF CWA GIVEN THAT FILTERED SUN STILL MAKING IT THROUGH ADVANCING CIRRUS SHIELD AND CUMULUS DEVELOPMENT. LAKE BREEZE WILL KEEP SHORE AREAS IN 70S THIS AFTERNOON. RC && .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 345 AM CDT SUNDAY NIGHT THROUGH FRIDAY... THE SURFACE LOW SLIDES BY TO THE SOUTH SUNDAY NIGHT...BUT LOOKS LIKE THERE COULD BE SOME LINGERING RAIN/SHOWERS ON THE BACK SIDE...THOUGH THE TREND SHOULD BE DOWNWARD. UPPER LEVEL FLOW BECOMES MORE AMPLIFIED MONDAY. WITH NORTHWEST FLOW ALOFT...ANOTHER DISTURBANCE WILL PASS OVER THE AREA AHEAD OF A SOUTHWARD MOVING COLD FRONT. THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND STORMS MONDAY BEFORE COOLER HIGH PRESSURE BUILDS IN FOR DRY CONDITIONS THROUGH AT LEAST MID WEEK. STORM CHANCES RETURN FOR THE LATTER HALF OF THE WEEK IN VERY AMPLIFIED NORTHWEST FLOW ALOFT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LAKE BREEZE APPROACHING ORD AT 22Z. * MVFR CEILINGS IN FOG AND RAIN SUNDAY MORNING AND DAYTIME. * ISOLATED THUNDERSTORM CHANCE. MM //DISCUSSION...UPDATED 18Z... SURFACE ANALYSIS INDICATES A WEAK LOW AND ASSOCIATED TROUGH/BOUNDARY WITHIN THE DOMINANT HIGH OVER MUCH OF THE GREAT LAKES. THIS HAS CAUSED THE WIND FIELD TO BECOME QUITE CONVOLUTED WITH A MESO-CYCLONE CENTERED NORTH OF CHICAGO. RADAR IMAGERY DOES INDICATE A LAKE BREEZE PROGGED TO REACH ORD/MDW AROUND 19-20Z. TIMING MAY NEED ADJUSTING IF THE BOUNDARY STALLS BETWEEN THE SHORE AND ORD...BUT AT THIS PACE WINDS SHOULD BE NORTHEAST AT 20Z. A MORE SUBSTANTIAL LOW WILL APPROACH INTO SUNDAY WITH MOISTURE CONTENT ON THE RISE THROUGH TONIGHT. FORECAST SOUNDINGS INDICATE A LOW LEVEL INVERSION FROM 09-13Z. SURFACE MOISTURE IS ADEQUATE ENOUGH TO ALLOW FOR SOME FOG...FOLLOWED BY THE ARRIVAL OF RAIN SUNDAY MORNING. RAIN/SHOWERY CONDITIONS ARE EXPECTED TO PERSIST MUCH OF THE DAY AND THERE WILL MAY ALSO BE A PERIOD OF THUNDER AS WELL. TIMING OF THUNDER IS UNDER QUESTION AS THE INITIAL ARRIVAL OF THE LOW MAY SUPPORT A BRIEF UPTICK IN LAPSE RATES...OTHERWISE WILL HAVE TO WAIT FOR ADDL SFC HEATING AFTER 20Z SUNDAY. MM //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM IN WINDS..LOW IN ORD LAKE BREEZE. * MEDIUM IN MVFR FOG...MEDIUM HIGH IN RAIN. * LOW IN THUNDER AND TIMING. MM //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE OF THUNDERSTORMS. MONDAY...CHANCE OF THUNDERSTORMS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...SLIGHT CHANCE OF SHOWERS LATE. FRIDAY...VFR. RODRIGUEZ && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
100 PM CDT SAT AUG 8 2015 .UPDATE... 1154 AM CDT 12Z RAOBS AND RECENT AMDAR SOUNDINGS SHOW A SIGNIFICANT WARM NOSE ABOVE 850 MB...AS WELL AS PLENTY OF DRY AIR BETWEEN 850 AND 700 MB. LIGHT STRATIFORM PRECIP REMNANTS ON NORTHERN EDGE OF EARLY MORNING MCS OVER IOWA HAS BEEN ERODING WITH EASTWARD EXTENT AS IT ENCOUNTERS HOSTILE ENVIRONMENT FOR PRECIP. SOME SCATTERED SPRINKLES COULD GET INTO PORTIONS OF WEST AND SOUTHWEST CWA THIS AFTERNOON AS THERE IS SOME FORCING FROM CONVECTIVELY INDUCED SHORTWAVE. HOWEVER WOULD NOT EXPECT ANY ORGANIZED RAIN TO SURVIVE INTO THE CWA. THE WARM NOSE ALOFT ALSO THROWS INTO DOUBT ANY ISOLATED CONVECTION BEING ABLE TO INITIATE IN SOUTHEAST CWA THIS AFTERNOON IN CONVERGENT AXIS OF DISSIPATING SURFACE LOW AND LAKE BREEZE EXPECTED TO MOVE INLAND. CONVECTIVE TEMPS IN MID 90S MAKE IT UNLIKELY THAT CAPE IS AS HIGH AS SHOWN ON SPC MESOANALYSIS...AS RAP INITIALIZATION HAS A HIGH BIAS WITH TEMPS. SOME CUMULUS HAS POPPED UP...BUT NOT APPEARING TOO AGITATED UNDER CIRRUS SHIELD. HAVE KEPT JUST SLIGHT CHANCE POPS IN SOUTHEAST 1/3 OF CWA THIS AFTERNOON. OTHERWISE...TEMPERATURES ARE EXHIBITING A NORTH TO SOUTH GRADIENT...DRIVEN BY LOWER STRATUS IN NORTHERN CWA KEEPING TEMPS IN 70S WHILE LOWER-MID 80S IN SOUTHEAST 1/2 OF CWA GIVEN THAT FILTERED SUN STILL MAKING IT THROUGH ADVANCING CIRRUS SHIELD AND CUMULUS DEVELOPMENT. LAKE BREEZE WILL KEEP SHORE AREAS IN 70S THIS AFTERNOON. RC && .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 345 AM CDT SUNDAY NIGHT THROUGH FRIDAY... THE SURFACE LOW SLIDES BY TO THE SOUTH SUNDAY NIGHT...BUT LOOKS LIKE THERE COULD BE SOME LINGERING RAIN/SHOWERS ON THE BACK SIDE...THOUGH THE TREND SHOULD BE DOWNWARD. UPPER LEVEL FLOW BECOMES MORE AMPLIFIED MONDAY. WITH NORTHWEST FLOW ALOFT...ANOTHER DISTURBANCE WILL PASS OVER THE AREA AHEAD OF A SOUTHWARD MOVING COLD FRONT. THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND STORMS MONDAY BEFORE COOLER HIGH PRESSURE BUILDS IN FOR DRY CONDITIONS THROUGH AT LEAST MID WEEK. STORM CHANCES RETURN FOR THE LATTER HALF OF THE WEEK IN VERY AMPLIFIED NORTHWEST FLOW ALOFT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * LAKE BREEZE APPROACHING AT 20Z. * MVFR CEILINGS IN FOG AND RAIN SUNDAY MORNING AND DAYTIME. * ISOLATED THUNDERSTORM CHANCE. MM //DISCUSSION...UPDATED 18Z... SURFACE ANALYSIS INDICATES A WEAK LOW AND ASSOCIATED TROUGH/BOUNDARY WITHIN THE DOMINANT HIGH OVER MUCH OF THE GREAT LAKES. THIS HAS CAUSED THE WIND FIELD TO BECOME QUITE CONVOLUTED WITH A MESO-CYCLONE CENTERED NORTH OF CHICAGO. RADAR IMAGERY DOES INDICATE A LAKE BREEZE PROGGED TO REACH ORD/MDW AROUND 19-20Z. TIMING MAY NEED ADJUSTING IF THE BOUNDARY STALLS BETWEEN THE SHORE AND ORD...BUT AT THIS PACE WINDS SHOULD BE NORTHEAST AT 20Z. A MORE SUBSTANTIAL LOW WILL APPROACH INTO SUNDAY WITH MOISTURE CONTENT ON THE RISE THROUGH TONIGHT. FORECAST SOUNDINGS INDICATE A LOW LEVEL INVERSION FROM 09-13Z. SURFACE MOISTURE IS ADEQUATE ENOUGH TO ALLOW FOR SOME FOG...FOLLOWED BY THE ARRIVAL OF RAIN SUNDAY MORNING. RAIN/SHOWERY CONDITIONS ARE EXPECTED TO PERSIST MUCH OF THE DAY AND THERE WILL MAY ALSO BE A PERIOD OF THUNDER AS WELL. TIMING OF THUNDER IS UNDER QUESTION AS THE INITIAL ARRIVAL OF THE LOW MAY SUPPORT A BRIEF UPTICK IN LAPSE RATES...OTHERWISE WILL HAVE TO WAIT FOR ADDL SFC HEATING AFTER 20Z SUNDAY. MM //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM-HIGH IN WINDS AND LAKE BREEZE. * MEDIUM IN MVFR FOG...MEDIUM HIGH IN RAIN. * LOW IN THUNDER AND TIMING. MM //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE OF THUNDERSTORMS. MONDAY...CHANCE OF THUNDERSTORMS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...SLIGHT CHANCE OF SHOWERS LATE. FRIDAY...VFR. RODRIGUEZ && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1154 AM CDT SAT AUG 8 2015 .UPDATE... 1154 AM CDT 12Z RAOBS AND RECENT AMDAR SOUNDINGS SHOW A SIGNIFICANT WARM NOSE ABOVE 850 MB...AS WELL AS PLENTY OF DRY AIR BETWEEN 850 AND 700 MB. LIGHT STRATIFORM PRECIP REMNANTS ON NORTHERN EGDE OF EARLY MORNING MCS OVER IOWA HAS BEEN ERODING WITH EASTWARD EXTENT AS IT ENCOUNTERS HOSTILE ENVIRONMENT FOR PRECIP. SOME SCATTERED SPRINKLES COULD GET INTO PORTIONS OF WEST AND SOUTHWEST CWA THIS AFTERNOON AS THERE IS SOME FORCING FROM CONVECTIVELY INDUCED SHORTWAVE. HOWEVER WOULD NOT EXPECT ANY ORGANIZED RAIN TO SURVIVE INTO THE CWA. THE WARM NOSE ALOFT ALSO THROWS INTO DOUBT ANY ISOLATED CONVECTION BEING ABLE TO INITIATE IN SOUTHEAST CWA THIS AFTERNOON IN CONVERGENT AXIS OF DISSIPATING SURFACE LOW AND LAKE BREEZE EXPECTED TO MOVE INLAND. CONVECTIVE TEMPS IN MID 90S MAKE IT UNLIKELY THAT CAPE IS AS HIGH AS SHOWN ON SPC MESOANALYSIS...AS RAP INITIALIZATION HAS A HIGH BIAS WITH TEMPS. SOME CUMULUS HAS POPPED UP...BUT NOT APPEARING TOO AGITATED UNDER CIRRUS SHIELD. HAVE KEPT JUST SLIGHT CHANCE POPS IN SOUTHEAST 1/3 OF CWA THIS AFTERNOON. OTHERWISE...TEMPERATURES ARE EXHIBITING A NORTH TO SOUTH GRADIENT...DRIVEN BY LOWER STRATUS IN NORTHERN CWA KEEPING TEMPS IN 70S WHILE LOWER-MID 80S IN SOUTHEAST 1/2 OF CWA GIVEN THAT FILTERED SUN STILL MAKING IT THROUGH ADVANCING CIRRUS SHIELD AND CUMULUS DEVELOPMENT. LAKE BREEZE WILL KEEP SHORE AREAS IN 70S THIS AFTERNOON. RC && .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 345 AM CDT SUNDAY NIGHT THROUGH FRIDAY... THE SURFACE LOW SLIDES BY TO THE SOUTH SUNDAY NIGHT...BUT LOOKS LIKE THERE COULD BE SOME LINGERING RAIN/SHOWERS ON THE BACK SIDE...THOUGH THE TREND SHOULD BE DOWNWARD. UPPER LEVEL FLOW BECOMES MORE AMPLIFIED MONDAY. WITH NORTHWEST FLOW ALOFT...ANOTHER DISTURBANCE WILL PASS OVER THE AREA AHEAD OF A SOUTHWARD MOVING COLD FRONT. THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND STORMS MONDAY BEFORE COOLER HIGH PRESSURE BUILDS IN FOR DRY CONDITIONS THROUGH AT LEAST MID WEEK. STORM CHANCES RETURN FOR THE LATTER HALF OF THE WEEK IN VERY AMPLIFIED NORTHWEST FLOW ALOFT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * LAKE BREEZE/NORTHEAST WINDS APPROACHING THIS AFTERNOON * MVFR CIGS/VIS POSSIBLE LATE TONIGHT INTO SUNDAY MORNING. * RAIN AND ISOLATED THUNDER SUNDAY MORNING. MM //DISCUSSION...UPDATED 12Z... VFR AND DRY CONDITIONS IN PLACE THIS MORNING AS WEAK SURFACE LOW CONTINUES TO WEAKEN. SOME LOWER STRATUS HAD BRIEFLY DEVELOPED EARLIER THIS MORNING BUT HAS ALREADY BEGUN TO ERODE AND WILL CONTINUE TO DO SO THIS MORNING. HAVE MAINTAINED DRY CONDITIONS THROUGH THIS AFTERNOON...BUT WITH AN ISOLATED SPRINKLE STILL BRIEFLY POSSIBLE. SOUTH SOUTHWEST WINDS WILL TURN MORE WEST AND NORTHWEST THROUGH THIS MORNING BEFORE WEAKENING FLOW ALLOWS DEVELOPING LAKE BREEZE TO PUSH ACROSS THE TERMINALS THIS AFTERNOON. HIGHER CHANCES FOR PRECIP...REDUCED VIS AND LOWER CEILINGS WILL ARRIVE LATE TONIGHT INTO EARLY SUNDAY MORNING WITH THE APPROACH OF ANOTHER SYSTEM. SOME TIMING DIFFERENCES WITH THE ONSET OF PRECIP WITH THE EXACT TIMING IN THE TAF LIKELY BEING CHANGED BUT WITH ITS ARRIVAL...IT WILL LIKELY PERSIST THROUGH THE REMAINING FORECAST PERIOD. HAVE LEFT OUT ANY MENTION OF THUNDER AT THIS TIME WITH THE HIGHEST INSTABILITY TO THE SOUTH OF THE TERMINALS...BUT WILL NEED TO MONITOR FOR POSSIBLE BETTER DEVELOPMENT WHICH COULD LEAD TO AT LEAST ISOLATED THUNDER DURING THIS TIME. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH WITH WIND SPEED/DIRECTION AND WIND SHIFT...MEDIUM ON TIMING. * HIGH WITH MVFR CIGS/VIS LATE TONIGHT INTO SUNDAY MORNING...MEDIUM LOW WITH TIMING. * HIGH WITH RAIN SUNDAY MORNING...MEDIUM ON TIMING...LOW WITH THUNDER CHANCES. MM //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE OF THUNDERSTORMS. MONDAY...CHANCE OF THUNDERSTORMS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...SLIGHT CHANCE OF SHOWERS LATE. FRIDAY...VFR. RODRIGUEZ && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1107 AM CDT SAT AUG 8 2015 .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 345 AM CDT SUNDAY NIGHT THROUGH FRIDAY... THE SURFACE LOW SLIDES BY TO THE SOUTH SUNDAY NIGHT...BUT LOOKS LIKE THERE COULD BE SOME LINGERING RAIN/SHOWERS ON THE BACK SIDE...THOUGH THE TREND SHOULD BE DOWNWARD. UPPER LEVEL FLOW BECOMES MORE AMPLIFIED MONDAY. WITH NORTHWEST FLOW ALOFT...ANOTHER DISTURBANCE WILL PASS OVER THE AREA AHEAD OF A SOUTHWARD MOVING COLD FRONT. THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND STORMS MONDAY BEFORE COOLER HIGH PRESSURE BUILDS IN FOR DRY CONDITIONS THROUGH AT LEAST MID WEEK. STORM CHANCES RETURN FOR THE LATTER HALF OF THE WEEK IN VERY AMPLIFIED NORTHWEST FLOW ALOFT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * LAKE BREEZE/NORTHEAST WINDS APPROACHING THIS AFTERNOON * MVFR CIGS/VIS POSSIBLE LATE TONIGHT INTO SUNDAY MORNING. * RAIN AND ISOLATED THUNDER SUNDAY MORNING. MM //DISCUSSION...UPDATED 12Z... VFR AND DRY CONDITIONS IN PLACE THIS MORNING AS WEAK SURFACE LOW CONTINUES TO WEAKEN. SOME LOWER STRATUS HAD BRIEFLY DEVELOPED EARLIER THIS MORNING BUT HAS ALREADY BEGUN TO ERODE AND WILL CONTINUE TO DO SO THIS MORNING. HAVE MAINTAINED DRY CONDITIONS THROUGH THIS AFTERNOON...BUT WITH AN ISOLATED SPRINKLE STILL BRIEFLY POSSIBLE. SOUTH SOUTHWEST WINDS WILL TURN MORE WEST AND NORTHWEST THROUGH THIS MORNING BEFORE WEAKENING FLOW ALLOWS DEVELOPING LAKE BREEZE TO PUSH ACROSS THE TERMINALS THIS AFTERNOON. HIGHER CHANCES FOR PRECIP...REDUCED VIS AND LOWER CEILINGS WILL ARRIVE LATE TONIGHT INTO EARLY SUNDAY MORNING WITH THE APPROACH OF ANOTHER SYSTEM. SOME TIMING DIFFERENCES WITH THE ONSET OF PRECIP WITH THE EXACT TIMING IN THE TAF LIKELY BEING CHANGED BUT WITH ITS ARRIVAL...IT WILL LIKELY PERSIST THROUGH THE REMAINING FORECAST PERIOD. HAVE LEFT OUT ANY MENTION OF THUNDER AT THIS TIME WITH THE HIGHEST INSTABILITY TO THE SOUTH OF THE TERMINALS...BUT WILL NEED TO MONITOR FOR POSSIBLE BETTER DEVELOPMENT WHICH COULD LEAD TO AT LEAST ISOLATED THUNDER DURING THIS TIME. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH WITH WIND SPEED/DIRECTION AND WIND SHIFT...MEDIUM ON TIMING. * HIGH WITH MVFR CIGS/VIS LATE TONIGHT INTO SUNDAY MORNING...MEDIUM LOW WITH TIMING. * HIGH WITH RAIN SUNDAY MORNING...MEDIUM ON TIMING...LOW WITH THUNDER CHANCES. MM //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE OF THUNDERSTORMS. MONDAY...CHANCE OF THUNDERSTORMS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...SLIGHT CHANCE OF SHOWERS LATE. FRIDAY...VFR. RODRIGUEZ && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
902 AM CDT SAT AUG 8 2015 .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 345 AM CDT SUNDAY NIGHT THROUGH FRIDAY... THE SURFACE LOW SLIDES BY TO THE SOUTH SUNDAY NIGHT...BUT LOOKS LIKE THERE COULD BE SOME LINGERING RAIN/SHOWERS ON THE BACK SIDE...THOUGH THE TREND SHOULD BE DOWNWARD. UPPER LEVEL FLOW BECOMES MORE AMPLIFIED MONDAY. WITH NORTHWEST FLOW ALOFT...ANOTHER DISTURBANCE WILL PASS OVER THE AREA AHEAD OF A SOUTHWARD MOVING COLD FRONT. THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND STORMS MONDAY BEFORE COOLER HIGH PRESSURE BUILDS IN FOR DRY CONDITIONS THROUGH AT LEAST MID WEEK. STORM CHANCES RETURN FOR THE LATTER HALF OF THE WEEK IN VERY AMPLIFIED NORTHWEST FLOW ALOFT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * WEST/NORTHWEST WINDS BECOMING NORTHEAST THIS AFTERNOON. * MVFR CIGS/VIS POSSIBLE LATE TONIGHT INTO SUNDAY MORNING. * RAIN SUNDAY MORNING...WITH POSSIBLE THUNDER. RODRIGUEZ/MM //DISCUSSION...UPDATED 12Z... VFR AND DRY CONDITIONS IN PLACE THIS MORNING AS WEAK SURFACE LOW CONTINUES TO WEAKEN. SOME LOWER STRATUS HAD BRIEFLY DEVELOPED EARLIER THIS MORNING BUT HAS ALREADY BEGUN TO ERODE AND WILL CONTINUE TO DO SO THIS MORNING. HAVE MAINTAINED DRY CONDITIONS THROUGH THIS AFTERNOON...BUT WITH AN ISOLATED SPRINKLE STILL BRIEFLY POSSIBLE. SOUTH SOUTHWEST WINDS WILL TURN MORE WEST AND NORTHWEST THROUGH THIS MORNING BEFORE WEAKENING FLOW ALLOWS DEVELOPING LAKE BREEZE TO PUSH ACROSS THE TERMINALS THIS AFTERNOON. HIGHER CHANCES FOR PRECIP...REDUCED VIS AND LOWER CEILINGS WILL ARRIVE LATE TONIGHT INTO EARLY SUNDAY MORNING WITH THE APPROACH OF ANOTHER SYSTEM. SOME TIMING DIFFERENCES WITH THE ONSET OF PRECIP WITH THE EXACT TIMING IN THE TAF LIKELY BEING CHANGED BUT WITH ITS ARRIVAL...IT WILL LIKELY PERSIST THROUGH THE REMAINING FORECAST PERIOD. HAVE LEFT OUT ANY MENTION OF THUNDER AT THIS TIME WITH THE HIGHEST INSTABILITY TO THE SOUTH OF THE TERMINALS...BUT WILL NEED TO MONITOR FOR POSSIBLE BETTER DEVELOPMENT WHICH COULD LEAD TO AT LEAST ISOLATED THUNDER DURING THIS TIME. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH WITH WIND SPEED/DIRECTION AND WIND SHIFT...MEDIUM ON EXACT TIMING...LOW MEDIUM ON SPEEDS BELOW 10KT. * HIGH WITH MVFR CIGS/VIS LATE TONIGHT INTO SUNDAY MORNING...MEDIUM LOW WITH EXACT TIMING. * HIGH WITH RAIN SUNDAY MORNING...MEDIUM ON EXACT TIMING...LOW WITH THUNDER CHANCES. RODRIGUEZ/MM //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE OF THUNDERSTORMS. MONDAY...CHANCE OF THUNDERSTORMS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...SLIGHT CHANCE OF SHOWERS LATE. FRIDAY...VFR. RODRIGUEZ && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
650 AM CDT SAT AUG 8 2015 .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 345 AM CDT SUNDAY NIGHT THROUGH FRIDAY... THE SURFACE LOW SLIDES BY TO THE SOUTH SUNDAY NIGHT...BUT LOOKS LIKE THERE COULD BE SOME LINGERING RAIN/SHOWERS ON THE BACK SIDE...THOUGH THE TREND SHOULD BE DOWNWARD. UPPER LEVEL FLOW BECOMES MORE AMPLIFIED MONDAY. WITH NORTHWEST FLOW ALOFT...ANOTHER DISTURBANCE WILL PASS OVER THE AREA AHEAD OF A SOUTHWARD MOVING COLD FRONT. THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND STORMS MONDAY BEFORE COOLER HIGH PRESSURE BUILDS IN FOR DRY CONDITIONS THROUGH AT LEAST MID WEEK. STORM CHANCES RETURN FOR THE LATTER HALF OF THE WEEK IN VERY AMPLIFIED NORTHWEST FLOW ALOFT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * WESTERLY WINDS BECOMING NORTHEAST THIS AFTERNOON. * MVFR CIGS/VIS POSSIBLE LATE TONIGHT INTO SUNDAY MORNING. * RAIN SUNDAY MORNING...WITH POSSIBLE THUNDER. RODRIGUEZ //DISCUSSION...UPDATED 12Z... VFR AND DRY CONDITIONS IN PLACE THIS MORNING AS WEAK SURFACE LOW CONTINUES TO WEAKEN. SOME LOWER STRATUS HAD BRIEFLY DEVELOPED EARILER THIS MORNING BUT HAS ALREADY BEGUN TO ERODE AND WILL CONTINUE TO DO SO THIS MORNING. HAVE MAINTAINED DRY CONDITIONS THROUGH THIS AFTERNOON...BUT WITH AN ISOLATED SPRINKLE STILL BRIEFLY POSSIBLE. SOUTH SOUTHWEST WINDS WILL TURN MORE WEST AND NORTHWEST THROUGH THIS MORNING BEFORE WEAKENING FLOW ALLOWS DEVELOPING LAKE BREEZE TO PUSH ACROSS THE TERMINALS THIS AFTERNOON. HIGHER CHANCES FOR PRECIP...REDUCED VIS AND LOWER CEILINGS WILL ARRIVE LATE TONIGHT INTO EARLY SUNDAY MORNING WITH THE APPROACH OF ANOTHER SYSTEM. SOME TIMING DIFFERENCES WITH THE ONSET OF PRECIP WITH THE EXACT TIMING IN THE TAF LIKELY BEING CHANGED BUT WITH ITS ARRIVAL...IT WILL LIKELY PERSIST THROUGH THE REMAINING FORECAST PERIOD. HAVE LEFT OUT ANY MENTION OF THUNDER AT THIS TIME WITH THE HIGHEST INSTABILITY TO THE SOUTH OF THE TERMINALS...BUT WILL NEED TO MONITOR FOR POSSIBLE BETTER DEVELOPMENT WHICH COULD LEAD TO AT LEAST ISOLATED THUNDER DURING THIS TIME. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH WITH WIND SPEED/DIRECTION AND WIND SHIFT...MEDIUM ON EXACT TIMING...LOW MEDIUM ON SPEEDS BELOW 10KT. * HIGH WITH MVFR CIGS/VIS LATE TONIGHT INTO SUNDAY MORNING...LOW MEDIUM WITH EXACT TIMING. * HIGH WITH RAIN SUNDAY MORNING...MEDIUM ON EXACT TIMING...LOW WITH POSSIBLE THUNDER. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...CHANCE OF THUNDERSTORMS. MONDAY...CHANCE OF THUNDERSTORMS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...SLIGHT CHANCE OF SHOWERS LATE. FRIDAY...VFR. RODRIGUEZ && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
404 AM CDT SAT AUG 8 2015 .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 345 AM CDT SUNDAY NIGHT THROUGH FRIDAY... THE SURFACE LOW SLIDES BY TO THE SOUTH SUNDAY NIGHT...BUT LOOKS LIKE THERE COULD BE SOME LINGERING RAIN/SHOWERS ON THE BACK SIDE...THOUGH THE TREND SHOULD BE DOWNWARD. UPPER LEVEL FLOW BECOMES MORE AMPLIFIED MONDAY. WITH NORTHWEST FLOW ALOFT...ANOTHER DISTURBANCE WILL PASS OVER THE AREA AHEAD OF A SOUTHWARD MOVING COLD FRONT. THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND STORMS MONDAY BEFORE COOLER HIGH PRESSURE BUILDS IN FOR DRY CONDITIONS THROUGH AT LEAST MID WEEK. STORM CHANCES RETURN FOR THE LATTER HALF OF THE WEEK IN VERY AMPLIFIED NORTHWEST FLOW ALOFT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * MVFR CIGS/VIS POSSIBLE THIS MORNING. * WESTERLY WINDS BECOMING NORTHEAST THIS AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... WEAKENING SURFACE LOW CONTINUES TO PUSH THROUGH THE REGION EARLY THIS MORNING WITH RADAR IMAGERY DEPICTING LIGHT ISOLATED SHOWERY ACTIVITY EAST/NORTHEAST OF THE TERMINALS. ANY FURTHER PRECIP DEVELOPMENT WILL REMAIN TO THE EAST OF ALL THE TERMINALS...WITH DRY CONDITIONS EXPECTED THIS MORNING THROUGH MUCH OF THE DAY. SHORT TERM GUIDANCE HINTING AT SOME TYPE OF LIGHT PRECIP LATER THIS AFTERNOON...BUT THINK THIS MAY BE A BIT AGRESSIVE AS FAIRLY DRY LOW LEVELS WILL REMAIN IN PLACE. IF ANYTHING WERE TO PUSH ACROSS THE TERMINALS LATER THIS AFTERNOON IT WOULD LIKELY ONLY BE AN ISOLATED SPRINKLE. VFR CEILINGS EXPECTED THIS MORNING AND THROUGH THE FORECAST PERIOD...WITH AREAS OF FOG STILL POSSIBLE EARLY THIS MORNING. SOUTH SOUTHWEST WINDS WILL TURN MORE WEST AND NORTHWEST THROUGH THIS MORNING BEFORE WEAKENING FLOW ALLOWS DEVELOPING LAKE BREEZE TO PUSH ACROSS THE TERMINALS THIS AFTERNOON. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 09Z... * MEDIUM IN MVFR CIGS/VIS THIS MORNING. * HIGH WITH WIND SPEED/DIRECTION AND WIND SHIFT...MEDIUM ON EXACT TIMING...LOW MEDIUM ON SPEEDS BELOW 10KT. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...CHANCE OF TSRA/MVFR. SOUTH-SOUTHEAST WINDS. MONDAY...SLGT CHANCE OF AFTN SHRA/TSRA. OTHERWISE VFR. NORTH- NORTHEAST WINDS. TUESDAY AND WEDNESDAY...VFR. NORTH-NORTHEAST WINDS. THURSDAY...VFR. WEST WINDS. RATZER && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
348 AM CDT SAT AUG 8 2015 .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 345 AM CDT SUNDAY NIGHT THROUGH FRIDAY... THE SURFACE LOW SLIDES BY TO THE SOUTH SUNDAY NIGHT...BUT LOOKS LIKE THERE COULD BE SOME LINGERING RAIN/SHOWERS ON THE BACK SIDE...THOUGH THE TREND SHOULD BE DOWNWARD. UPPER LEVEL FLOW BECOMES MORE AMPLIFIED MONDAY. WITH NORTHWEST FLOW ALOFT...ANOTHER DISTURBANCE WILL PASS OVER THE AREA AHEAD OF A SOUTHWARD MOVING COLD FRONT. THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND STORMS MONDAY BEFORE COOLER HIGH PRESSURE BUILDS IN FOR DRY CONDITIONS THROUGH AT LEAST MID WEEK. STORM CHANCES RETURN FOR THE LATTER HALF OF THE WEEK IN VERY AMPLIFIED NORTHWEST FLOW ALOFT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * MVFR VIS POSSIBLE THIS MORNING. * WESTERLY WINDS BECOMING NORTHEAST THIS AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... WEAKENING SURFACE LOW CONTINUES TO PUSH THROUGH THE REGION EARLY THIS MORNING WITH RADAR IMAGERY DEPICTING LIGHT ISOLATED SHOWERY ACTIVITY EAST/NORTHEAST OF THE TERMINALS. ANY FURTHER PRECIP DEVELOPMENT WILL REMAIN TO THE EAST OF ALL THE TERMINALS...WITH DRY CONDITIONS EXPECTED THIS MORNING THROUGH MUCH OF THE DAY. SHORT TERM GUIDANCE HINTING AT SOME TYPE OF LIGHT PRECIP LATER THIS AFTERNOON...BUT THINK THIS MAY BE A BIT AGRESSIVE AS FAIRLY DRY LOW LEVELS WILL REMAIN IN PLACE. IF ANYTHING WERE TO PUSH ACROSS THE TERMINALS LATER THIS AFTERNOON IT WOULD LIKELY ONLY BE AN ISOLATED SPRINKLE. VFR CEILINGS EXPECTED THIS MORNING AND THROUGH THE FORECAST PERIOD...WITH AREAS OF FOG STILL POSSIBLE EARLY THIS MORNING. SOUTH SOUTHWEST WINDS WILL TURN MORE WEST AND NORTHWEST THROUGH THIS MORNING BEFORE WEAKENING FLOW ALLOWS DEVELOPING LAKE BREEZE TO PUSH ACROSS THE TERMINALS THIS AFTERNOON. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM IN MVFR VIS THIS MORNING. * HIGH WITH WIND SPEED/DIRECTION AND WIND SHIFT...MEDIUM ON EXACT TIMING...LOW MEDIUM ON SPEEDS BELOW 10KT. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...CHANCE OF TSRA/MVFR. SOUTH-SOUTHEAST WINDS. MONDAY...SLGT CHANCE OF AFTN SHRA/TSRA. OTHERWISE VFR. NORTH- NORTHEAST WINDS. TUESDAY AND WEDNESDAY...VFR. NORTH-NORTHEAST WINDS. THURSDAY...VFR. WEST WINDS. RATZER && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
332 AM CDT SAT AUG 8 2015 .SHORT TERM... 326 AM CDT THROUGH SUNDAY... AN ACTIVE PATTERN WILL BE IN PLACE FOR A FEW DAYS BEFORE THINGS QUIET DOWN NEXT WEEK. SOMEWHAT MESSY SURFACE PATTERN IN PLACE WITH A WEAK SURFACE LOW/TROUGH AXIS PROGGED TO SINK SOUTHEASTWARD SLOWLY TODAY...THOUGH IT WILL LOSE SOME DEFINITION TODAY...ALLOWING WEAK HIGH PRESSURE TO CONTROL THE LOWER LEVELS. ALOFT...HIGH PRESSURE REMAINS ANCHORED OVER THE SOUTHERN STATES...A STRONG CLOSED LOW IN THE CANADIAN PRAIRIES...AND LOW PRESSURE MOVING INTO THE GREAT BASIN. COMPLEX OF THUNDERSTORMS MARCHING EASTWARD ACROSS KS/NE/IA IS ALREADY SHOWING SOME WEAKENING SIGNS IN THE IR IMAGERY...ESPECIALLY ON ITS NORTHERN AND EASTERN EDGES...AS THE LOW LEVEL JET FEEDING THIS MCS WILL REMAIN FOCUSED IN THE PLAINS. THERE IS AN UPPER LEVEL SHORTWAVE/MODEST SPEED MAX AHEAD OF THE GREAT BASIN LOW THAT WILL CONTINUE EASTWARD AROUND THE NORTHERN PERIPHERY OF THE SOUTHERN UNITED STATES HIGH PRESSURE RIDGE IN THE STRONGER WESTERLY FLOW ACROSS THE MIDWEST. THIS WAVE IS THE COMPLICATING FACTOR IN THE FORECAST FOR THIS AFTERNOON. NAM/GFS/ECMWF/SREF ALL CONTINUE TO SIGNIFICANTLY WEAKEN THE MCS AS IT ENTERS INTO ILLINOIS...AND ESPECIALLY NORTHEAST ILLINOIS. SHORT-TERM GUIDANCE INCLUDING THE RAP/HRRR/EXPERIMENTAL HRRR PAINT A SLIGHTLY SIMILAR PICTURE...BUT SHOW SOME OF THE PRECIPITATION SURVIVING THROUGH THE AREA. SOUNDINGS IN NE IL/NW IN ARE QUITE DRY IN THE LOW LEVELS..AND THIS REMAINS THE CASE THROUGH THE DAY AS WELL. AT THIS POINT OUR FEELING IS THAT THIS WILL ARRIVE IN THE FORM OF SPRINKLES OR POSSIBLY SOME VERY LIGHT RAIN. HAVE GONE WITH SPRINKLES FOR NOW...THOUGH THIS WILL BEAR WATCHING AS THIS COMPLEX CONTINUES EASTWARD AND MAY INTRODUCE POPS BEFORE THIS SHIFT ENDS IF THIS TREND CONTINUES. CLOUD COVER WILL THICKEN QUICKLY TODAY REGARDLESS...AND THIS COULD PREVENT SOME LOCATIONS FROM GETTING INTO THE 80S TODAY WITH SOME INCREASE IN HUMIDITY. THERE COULD BE SOME ADDITIONAL SHOWERS OR STORMS AHEAD OF THE SOUTHEASTWARD SINKING SURFACE TROUGH OUT AHEAD OF MAIN STORM SYSTEM THIS AFTERNOON WHERE A MENTION EXISTS THIS AFTERNOON/EARLY EVENING. ADDITIONAL SHORTWAVE NOTED BY 500 MB SPEED MAX AGAIN AROUND 50 KT WILL MOVE AROUND THE PERIPHERY ALONG A SIMILAR PATH...WITH THE NEXT ONE SLATED FOR SUNDAY MORNING. THE DIFFERENCE WITH THIS WAVE IS THE LOW LEVEL JET/MOISTURE TRANSPORT WILL BE FOCUSED CLOSER TO OUR REGION. LAPSE RATES AT THIS POINT DO NOT LOOK IMPRESSIVE AT THIS POINT IN TIME. THE MAIN FOCUS TIME WILL BE LATE TONIGHT INTO EARLY SUNDAY. THE LLJ/MOISTURE CONVERGENCE PEAKS IN OUR SOUTHERN ZONES WHERE HIGHER CONFIDENCE IN HEAVIER PRECIPITATION RATES EXIST GIVEN PWATS AROUND 2". MOST AREAS...EXCEPT POSSIBLY THE FAR NORTH AND EAST...LOOK TO SEE PRECIP WITH THIS ROUND. DESTABILIZATION LATER IN THE DAY LIKELY WILL BE INHIBITED BY EXTENSIVE CLOUD COVER FROM MORNING ACTIVITY ALSO. SPC STILL HIGHLIGHTS SOUTHERN AND EASTERN PORTIONS OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...THOUGH STILL MANY QUESTION MARKS ON THE EVOLUTION. THE HIGHER RISK LOOKS TO BE JUST SOUTH OF THE AREA AS MODELS KEEP THE SURFACE LOW SOUTH AND LEAVE OUR AREA IN THE COLD SECTOR. WITH THE FLOW TURNING NORTHWESTERLY AND ADDITIONAL DISTURBANCES MOVING THROUGH...WILL STILL NEED TO KEEP AN EYE ON IF ANY CLEARING OCCURS OR IF THE WARM SECTOR INCHES A BIT FARTHER NORTH. AT THIS POINT...MOST AREAS HANG ONTO CLOUDY CONDITIONS WITH HIGHS NOT GETTING OUT OF THE 70S. KMD && .LONG TERM... 259 PM CDT LATEST MORNING DISCUSSION FORTHCOMING...PREVIOUS DISCUSSION BELOW... SATURDAY NIGHT THROUGH FRIDAY... THE BEST CHANCE FOR PRECIP AND STORMS WILL BE LATE SATURDAY NIGHT INTO SUNDAY MORNING WITH AN ADDITIONAL SLIGHT CHANCE TO CHANCE OF PRECIP THROUGH MONDAY AFTERNOON. AS THE UPPER LEVEL LOW SHIFTS EAST OVER QUEBEC EARLY NEXT WEEK...WE WILL GET UNDER A RIDGING PATTERN AND A SURFACE HIGH PRESSURE SYSTEM. THIS WILL LEAD TO DRY CONDITIONS THROUGH MOST OF NEXT WEEK. FOR SATURDAY NIGHT AND SUNDAY... EXPECTING A LINGERING MCV TO SUPPORT STORM DEVELOPMENT OVER IOWA SATURDAY AFTERNOON AND EVENING WITH THE AREA OF STORMS SHIFTING EAST ACROSS NORTHERN IL AND NW INDIANA EARLY SUNDAY MORNING. HAVE THE GREATEST CONFIDENCE IN WIDESPREAD RAIN ALONG AND SOUTH OF I-88. NOT OVERLY EXCITED ABOUT SVR POTENTIAL AS THE STORM COMPLEX MOVES INTO THE REGION. THE GFS KEEPS THE LLJ NOSE OVER WEST CENTRAL IL WHILE THE NAM BRINGS IT INTO CENTRAL IL. THE NAM IS TYPICALLY A BIT TOO AMBITIOUS WITH CAPE VALUES AS WELL SO LEANING TOWARD THE GFS SOLUTION OF A DECAYING MCS. HOWEVER...IF THE NAM IS CORRECT...THE MCS COULD PRODUCE SOME STRONG WINDS. EITHER WAY MOST IF NOT ALL OF THE CWA SHOULD SEE NEEDED ACCUMULATING RAINFALL FROM THE DECAYING SYSTEM OF STORMS. KEPT A CHANCE OF AFTERNOON AND EVENING PRECIP AS I AM NOT OVERLY CONFIDENT THAT WE WILL DESTABILIZE ENOUGH TO SEE A SECOND ROUND OF STORMS SUNDAY. HAVE LOW CONFIDENCE IN WHEN AND WHERE ADDITIONAL SHOWERS AND STORMS WILL FORM SUNDAY AFTERNOON AND EVENING. DEVELOPMENT DEPENDS ON WHERE THE MCV STALLS AND HOW QUICKLY WE RECOVER FROM THE MORNING/S CONVECTION. GUIDANCE FEATURES NEW DEVELOPMENT ROUGHLY ALONG AND EAST OF THE I-55 CORRIDOR...BUT ONCE AGAIN HAVE LOW CONFIDENCE IN TIMING...EXACT LOCATION...AND COVERAGE OF ANY ADDITIONAL STORMS. IF AFTERNOON STORMS DO DEVELOP...STRAYED FROM THE OVERLY AMBITIOUS NAM WHICH SEEMS TO HAVE MUCH TOO HIGH CAPE AND SHEAR VALUES. KEPT HIGH TEMPS SUNDAY IN THE LOW 80S AND HIGH TEMPS COULD BE EVEN LOWER IF THE CLOUD SHIELD FROM THE MORNING/S CONVECTION LINGERS THROUGHOUT THE DAY. MONDAY THROUGH FRIDAY... THE UPPER LEVEL TROUGH/S SECONDARY TROUGH AXIS SWINGS THROUGH MONDAY MORNING WITH SURFACE HIGH PRESSURE BUILDING IN BEHIND IT. HAVE A SLIGHT CHANCE TO LOW END CHANCE OF SHOWERS AND STORMS OCCURRING AS THE TROUGH AXIS AND UPPER LEVEL VORT STREAMER SLIDE THROUGH MONDAY AFTERNOON. NOT EXPECTING WIDESPREAD DEVELOPMENT MONDAY AFTERNOON. DRY CONDITIONS ARE THEN FORECAST THROUGH THURSDAY AS WE ARE UNDER THE INFLUENCE OF A SURFACE HIGH. LAKE BREEZES ARE POSSIBLE MONDAY THROUGH WEDNESDAY LEADING TO LAKE SIDE COOLING. AWAY FROM THE LAKE EXPECTING HIGH TEMPS AROUND 80. THE HIGH THEN DRIFTS EAST LATE IN THE WEEK WITH ANOTHER LOW PRESSURE SYSTEM IMPACTING THE MID WEST THURSDAY NIGHT INTO FRIDAY. GUIDANCE DIFFERS IN THE EXACT PATH OF THIS LOW SO KEPT PRECIP CHANCES IN THE CHANCE OR LOWER RANGE. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * MVFR VIS POSSIBLE THIS MORNING. * WESTERLY WINDS BECOMING NORTHEAST THIS AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... WEAKENING SURFACE LOW CONTINUES TO PUSH THROUGH THE REGION EARLY THIS MORNING WITH RADAR IMAGERY DEPICTING LIGHT ISOLATED SHOWERY ACTIVITY EAST/NORTHEAST OF THE TERMINALS. ANY FURTHER PRECIP DEVELOPMENT WILL REMAIN TO THE EAST OF ALL THE TERMINALS...WITH DRY CONDITIONS EXPECTED THIS MORNING THROUGH MUCH OF THE DAY. SHORT TERM GUIDANCE HINTING AT SOME TYPE OF LIGHT PRECIP LATER THIS AFTERNOON...BUT THINK THIS MAY BE A BIT AGRESSIVE AS FAIRLY DRY LOW LEVELS WILL REMAIN IN PLACE. IF ANYTHING WERE TO PUSH ACROSS THE TERMINALS LATER THIS AFTERNOON IT WOULD LIKELY ONLY BE AN ISOLATED SPRINKLE. VFR CEILINGS EXPECTED THIS MORNING AND THROUGH THE FORECAST PERIOD...WITH AREAS OF FOG STILL POSSIBLE EARLY THIS MORNING. SOUTH SOUTHWEST WINDS WILL TURN MORE WEST AND NORTHWEST THROUGH THIS MORNING BEFORE WEAKENING FLOW ALLOWS DEVELOPING LAKE BREEZE TO PUSH ACROSS THE TERMINALS THIS AFTERNOON. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM IN MVFR VIS THIS MORNING. * HIGH WITH WIND SPEED/DIRECTION AND WIND SHIFT...MEDIUM ON EXACT TIMING...LOW MEDIUM ON SPEEDS BELOW 10KT. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...CHANCE OF TSRA/MVFR. SOUTH-SOUTHEAST WINDS. MONDAY...SLGT CHANCE OF AFTN SHRA/TSRA. OTHERWISE VFR. NORTH- NORTHEAST WINDS. TUESDAY AND WEDNESDAY...VFR. NORTH-NORTHEAST WINDS. THURSDAY...VFR. WEST WINDS. RATZER && .MARINE... 307 AM CDT DESPITE LOW PRESSURE NEAR THE SOUTHERN END OF THE LAKE WEAKENING THIS MORNING...HIGH PRESSURE TO THE EAST/NORTHEAST IS ALLOWING FOR A FAIRLY TIGHT SURFACE GRADIENT ACROSS MUCH OF THE LAKE. EAST SOUTHEAST WINDS OF 15 TO 25 KT WITH OCCASIONAL GUSTS TO 30 KT CONTINUE EARLY THIS MORNING OVER MUCH OF THE OPEN WATERS BUT AS THIS LOW SLOWLY MOVES EAST...STRONGEST WINDS WILL BECOME MORE FOCUSED ACROSS THE NORTH HALF THROUGH MID TO LATE MORNING BEFORE OBSERVING A DIMINISHING TREND INTO THE AFTERNOON. IT IS BECOMING MORE LIKELY FOR A FURTHER SOUTHWARD TREND WITH THE NEXT LOW PRESSURE SYSTEM ON SUNDAY AND ALTHOUGH DIRECTIONS WILL LIKELY VARY...SPEEDS ARE NOT EXPECTED TO BE AS HIGH AS PREVIOUSLY THOUGHT. BY MONDAY...THIS LOW WILL BE EAST OF THE LAKE WITH NORTHERLY WINDS EXPECTED TO PREVAIL THROUGH MID WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
136 AM EDT SAT AUG 8 2015 .SYNOPSIS... ISSUED AT 814 PM EDT FRI AUG 7 2015 AN UPPER LEVEL DISTURBANCE TRACKING ACROSS THE GREAT LAKES TONIGHT MAY BRING AN ISOLATED SHOWER TO PARTS OF EXTREME NORTHWEST INDIANA AND SOUTHWEST LOWER MICHIGAN. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE UPPER 50S TO LOWER 60S. HIGH TEMPERATURES ON SATURDAY WILL REACH BACK TO AROUND THE 80 DEGREE MARK. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 410 PM EDT FRI AUG 7 2015 A COMPACT UPPER LEVEL SHORT WAVE WILL CONTINUE EASTWARD ACROSS THE WESTERN GREAT LAKES THIS EVENING...ALTHOUGH LATEST SHORT TERM TRENDS SEEM TO SUGGEST THIS SHORT WAVE IS BECOMING INCREASINGLY SHEARED. A LARGE AREA OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS IS ACCOMPANYING THIS VORT. SHORT TERM RAP TRENDS SUGGEST THIS WAVE WILL BECOMING INCREASINGLY SHEARED WITH A MORE NARROWED CHANNEL OF DPVA WORKING FROM WEST TO EAST ACROSS THE LOCAL AREA IN THE 22Z- 04Z TIMEFRAME. LOW LEVEL THETAE TROUGH CURRENTLY RESIDING ACROSS THE AREA IS PROVIDING A FAIRLY SHARP WEST-EAST INSTABILITY GRADIENT FROM THE MID MS VALLEY TO THE OHIO VALLEY...AND WOULD EXPECT SOME DIMINISHING TREND IN COVERAGE AS THIS WAVE LOSES SOME POTENCY AND DUE TO EFFECTS OF INITIALLY DRY AIR MASS ACROSS THE REGION. HAVE MAINTAINED SOME SLIGHT CHANCE POPS PARTICULARLY ACROSS THE FAR NORTHWEST/NORTH THIS EVENING FOLLOWING THIS FORCING...WITH MORE QUESTIONABLE MOISTURE RETURN ACROSS REMAINDER OF THE AREA ARGUING FOR MAINTENANCE OF DRY FORECAST. FORCING WITH THIS WAVE WILL WANE LATE EVENING...BUT LAGGING LOW LEVEL THETAE RIDGE MAY BEGIN TO HAVE SOME INFLUENCE OVERNIGHT INTO EARLY SATURDAY MORNING. HAVE OPTED TO KEEP SOME SLIGHT CHANCE POPS GOING OVERNIGHT INTO EARLY SATURDAY MORNING ACROSS THE NORTH/NORTHWEST DUE TO LINGERING ADVECTIVE FORCING AND APPROACH OF A VERY WEAK REMNANT SFC TROUGH. SOME EASTWARD PROGRESSION OF DAMPENED LOW LEVEL THERMAL RIDGING ON SATURDAY SHOULD SOMEWHAT OFFSET EXPECTED MORE CLOUD COVER ON SATURDAY FOR HIGHS ONCE AGAIN AROUND 80...OR POSSIBLY INTO THE LOWER 80S DEPENDING ON EXTENT OF CLOUD COVER. && .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 410 PM EDT FRI AUG 7 2015 AN UPPER LEVEL SYSTEM OVER THE WESTERN CONUS WILL EJECT AN UPPER LEVEL TROF OVER THE LARGE UPPER LEVEL SOUTHERN PLAINS RIDGE AND THEN THE TROF WILL MOVE INTO THE UPPER GREAT LAKES REGION BY EARLY SUNDAY. NCEP MODELS...THE CANADIAN GEM AND THE ECMWF WERE SHOWING LARGE DIFFERENCES IN HANDLING THIS SYSTEM. FAVOR A SOUTHERN TRACK WHICH IS SUPPORTED THE BY ECMWF AND THE CPS ANALOGS. ALSO...MOST MODELS TRACKED THE SYSTEM EARLIER THIS WEEK TOO FAR NORTH. SO FOR THIS PACKAGE...KEPT A CHANCE FOR STORMS SUNDAY. HOWEVER...INCREASED STORM CHANCES A LITTLE OVER SOUTHWEST AREAS IN DEFERENCE TO THE ECMWF. IF THE SOUTHERN TRACK VERIFIES...CHANCES FOR SEVERE STORMS SHOULD BE LIMITED MORE TO THE SOUTH AND SOUTHWEST. OTHERWISE...SOME LINGERING SHOWERS AND STORMS ARE POSSIBLE MONDAY AND THEN CONDITIONS SHOULD BE DRY WITH TEMPERATURES A LITTLE BELOW NORMAL AS A LARGE UPPER LEVEL TROF REMAINS OVER THE AREA NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 136 AM EDT SAT AUG 8 2015 PRIMARILY VFR CONDITIONS EXPECTED THIS PERIOD. SUBTLE LOW LEVEL THETA-E RIDGE AND WEAK MIDLEVEL SHORTWAVE MAY TOUCH OFF A FEW ISOLATED SHOWERS THIS AFTERNOON BUT CHANCES TOO LOW FOR INCLUSION IN THE TAF AND IMPACTS MINIMAL ANYWAY. DESPITE SLIGHTLY INCREASED MOISTURE...CEILINGS EXPECTED TO REMAIN ABOVE 3 KFT. WINDS WILL SLOWLY VEER TO A MORE WESTERLY DIRECTION BY THIS AFTERNOON...BECOMING LIGHT AND VARIABLE BY THE END OF THE PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...T SHORT TERM...MARSILI LONG TERM...SKIPPER AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS TOPEKA KS
644 PM CDT SUN AUG 9 2015 ...UPDATE TO SHORT TERM CONVECTIVE FORECAST AND AVIATION FORECAST DISCUSSION... .UPDATE... ISSUED AT 629 PM CDT SUN AUG 9 2015 THE NEXT 12 HOURS OF THE FORECAST REMAIN QUITE UNCERTAIN IN TERMS OF DETAILS. OVER THE NEXT FEW HOURS, EXPECT ELEVATED SHOWERS TO CONTINUE WITHOUT MUCH CHANCE OF INTENSIFICATION. AT THE SAME TIME, THE ATMOSPHERE OVER NORTHEAST KANSAS IS VERY UNSTABLE AND ONLY WEAKLY CAPPED (PER 00Z TOP SOUNDING) SO IF THE LIFT PRODUCING THESE SHOWERS CAN MANAGE TO LIFT SURFACE BASED PARCELS AN ISOLATED STRONG STORM WOULD BECOME QUICKLY POSSIBLE. WILL ALSO BE CLOSELY WATCHING THE THUNDERSTORM CLUSTER IN NORTHERN NEBRASKA AS IT HAS NOW BEGUN MORE OF A SOUTHWARD PROPAGATION COMPONENT. THIS CLUSTER SEEMS LIKELY TO WORK ITS WAY SOUTHEAST THROUGH THE EVENING, AND EVEN IF IT SHOULD WEAKEN BEFORE ARRIVAL OR PASS EAST OF THE FORECAST AREA, THERE WOULD LIKELY BE AN OUTFLOW BOUNDARY PUSHING THROUGH THE AREA WHICH MAY ACT AS A FOCUS FOR LOCALIZED CONVECTIVE DEVELOPMENT OVERNIGHT. FINALLY, ALSO CONTINUE TO WATCH THE AREA OF LIFT MOVING OUT OF FAR WESTERN OKLAHOMA AND SOUTHWEST KANSAS AS THE RAP/HRRR IN PARTICULAR ALONG WITH SOME LARGER SCALE MODELS ARE CONSISTENT IN DEVELOPING AN MCS IN THESE AREAS WHICH COULD IMPACT AT LEAST SOUTHERN PARTS OF THE FORECAST AREA. THROUGH ALL OF THESE UNCERTAINTIES REGARDING FORCING MECHANISMS, THE OVERNIGHT AIRMASS IS LIKELY TO REMAIN QUITE UNSTABLE, WITH FORECAST SOUNDINGS INDICATING AMPLE CAPE ROOTED AS LOW AS 2000 FEET AGL...AND SHOULD STORMS DEVELOP THEY WILL MAINTAIN THE CAPABILITY TO PRODUCE STRONG TO SEVERE STORMS WITH DAMAGING WIND THE MAIN HAZARD AND SOME POTENTIAL FOR LARGE HAIL. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 313 PM CDT SUN AUG 9 2015 CURRENT SURFACE ANALYSIS SHOWS THE MAIN SYNOPTIC BOUNDARY EXTENDING SOUTHWARD FROM KANSAS CITY TO WICHITA, WHICH IS FORECAST TO SAG SOUTHWARD THROUGH THE AFTERNOON AND EVENING HOURS. ALTHOUGH THE MORE EVIDENT THERMAL GRADIENT HAS PUSHED INTO SOUTHEAST KS AND HAS BEEN RESPONSIBLE FOR SCATTERED SHOWERS AND ISOLATED THUNDER THIS MORNING. THIS HAS KEPT THE CLOUD COVER AROUND MUCH LONGER THAN FORECASTED, BUT AN AREA OF CLEAR SKIES IS WORKING EASTWARD ACROSS NORTHEAST KS, WHICH MAY ALLOW TEMPERATURES TO WARM INTO THE LOWER TO MIDDLE 90S. HIGH MOISTURE POOLING IN THE BOUNDARY LAYER HAS KEPT DEW POINTS IN THE MID TO UPPER 70S. EXPECT THAT HEAT INDICES WILL BE IN THE LOWER 100S THROUGH EARLY EVENING FOR LOCATIONS ALONG AND SOUTH OF I-70. THERE WILL BE A FEW THINGS OF CONCERN LATER THIS EVENING AND OVERNIGHT. THE MODELS SHOW A SHORTWAVE TROUGH ON THE NORTHERN PERIPHERY OF THE UPPER HIGH CENTERED OVER THE SOUTHERN PLAINS WILL TRACK ACROSS SOUTHERN KS TONIGHT. THIS MAY SUPPORT THE DEVELOPMENT OF AN MCS OR MULTICELL CLUSTER IN WESTERN OR CENTRAL KS THIS EVENING NORTH OF THE SURFACE BOUNDARY. SURFACE BASED CONVECTION HAS ALREADY BEGAN IN NORTHWEST KS. AS THAT BOUNDARY DRIFTS SOUTHWARD THE TRACK OF THE MCS MAY ALSO DO THE SAME AS DEPICTED BY THE NAM. THE PAST FEW RUNS OF THE HRRR HAVE BEEN CLIPPING THE SOUTHERN FORECAST AREA WITH THIS MCS. INSTABILITY HAS BEEN SOMEWHAT LIMITED TODAY ACROSS SOUTHERN KS AS OPPOSED TO NORTHERN KS, WHICH HAS SET UP A DECENT GRADIENT. THEREFORE IT IS UNCERTAIN HOW SEVERE THESE STORMS WILL BE THIS EVENING, BUT THE TRACK MAY BE MORE FOCUSED ALONG THIS INSTABILITY GRADIENT INSTEAD. AS FOR NOW THE BEST CHANCES FOR PRECIP WILL BE SOUTH OF I-70 LATE THIS EVENING AND EARLY MORNING WITH THE SLIGHT CHANCE FOR A STRONG STORM. WITH PLENTY OF MOISTURE AROUND AND LIGHT LOW LEVEL WINDS ASSOCIATED WITH THE BOUNDARY THERE IS A CHANCE FOR HAZE AND OR FOG EARLY TOMORROW MORNING. THERE ARE SOME INDICATIONS THAT THE SKIES COULD CLEAR LATE TONIGHT AND ALLOW FOR BOUNDARY LAYER COOLING. A FEW OF THE MODELS ARE HINTING AT A NORTHERN SHORTWAVE THAT WILL TRACK OVER SD AND NE OVERNIGHT. THIS MAY ALSO SUPPORT A SOUTHEASTWARD MOVING MCS THAT COULD REACH NORTHERN KS AROUND SUNRISE. IN FACT, THE INSTABILITY IS ALREADY DECENT IN THAT AREA, WHICH WOULD SUPPORT THIS SCENARIO BETTER. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 313 PM CDT SUN AUG 9 2015 THERE IS NOT MUCH CHANGE IN THE FORECAST FOR MONDAY NIGHT THROUGH SUNDAY AS MODELS CONTINUE TO SHOW AN UPPER LEVEL RIDGE AMPLIFYING TO THE WEST AND SOUTHWEST CAUSING NORTHWEST FLOW TO SET UP OVER THE FORECAST AREA. ABOUT THE ONLY THING OF CONCERN IS THE POSSIBILITY FOR SOME ELEVATED PRECIP ACROSS NORTH CENTRAL KS LATE TUESDAY NIGHT AND WEDNESDAY MORNING. THERE ARE INDICATIONS THAT CONVECTION IN THE MOUNTAINS COULD GENERATE A VORT MAX AND THEN DRIFT EAST AND SOUTH THROUGH CENTRAL KS. FOR NOW MOST GUIDANCE KEEPS ANY PRECIP JUST TO THE WEST OF THE FORECAST AREA. THIS SEEMS TO MAKE SINCE AS MODELS BRING THE CENTER OF THE 850 MB RIDGE OVER THE FORECAST AREA BY 12Z WED WITH NO REAL RETURN FLOW AND THE DEEPER MOISTURE AXIS REMAINING OVER WESTERN KS. SO THE FORECAST REMAINS DRY THROUGH NEXT WEEKEND WITH NO OBVIOUS SIGNS OF FORCING IMPACTING THE FORECAST AREA AFTER WEDNESDAY. TEMPS ARE EXPECTED TO BE COOLER THAN NORMAL FOR TUESDAY THROUGH THURSDAY. MODELS ARE IN AGREEMENT THAT A MODIFIED HIGH PRESSURE SYSTEM WILL BUILD INTO THE AREA WITH SOME WEAK COLD AIR ADVECTION AND DRYER AIR. BECAUSE OF THIS LOWS SHOULD BE IN THE LOWER AND MID 60S WITH HIGHS IN THE 80S. BY FRIDAY AND INTO THE WEEKEND, THE UPPER RIDGE IS EXPECTED TO PROPAGATE EAST INTO THE PLAINS AS AN UPPER TROUGH OVER THE PACIFIC NORTHWEST COAST MOVES INLAND. THIS SHOULD SHIFT THE THERMAL RIDGE OUT INTO THE PLAINS WITH HIGHS WARMING BACK INTO THE LOWER AND MID 90S FOR THE WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 629 PM CDT SUN AUG 9 2015 THIS TAF HAS ABOVE NORMAL UNCERTAINTY ESPECIALLY BEYOND 05Z. VFR CONDITIONS WITH SCATTERED SHOWERS ARE LIKELY THIS EVENING. AFTER 04-06Z, THERE IS POTENTIAL FOR MORE ORGANIZED STORMS TO MOVE OVER/NEAR TAF SITES, BUT STORMS COULD JUST AS EASILY REMAIN BOTH NORTH AND SOUTH OF SITES. FOR NOW HAVE HIGHLIGHTED BEST POTENTIAL TIMING WITH A VCTS. IT THEN APPEARS THAT SEVERAL HOURS OF MVFR CIGS ARE LIKELY AFTER SUNRISE THROUGH THE MORNING, ALTHOUGH THERE IS POTENTIAL FOR THESE CIGS TO BE IN THE IFR RANGE ESPECIALLY BETWEEN 12-14Z...OR COULD REMAIN SCATTERED WITH NO CEILING. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARJENBRUCH SHORT TERM...SANDERS LONG TERM...WOLTERS AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
527 PM MDT SUN AUG 9 2015 .SHORT TERM...(THIS AFTERNOON THROUGH MONDAY) ISSUED AT 132 PM MDT SUN AUG 9 2015 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOW RIDGE CONTINUING TO DOMINATE PATTERN ACROSS SOUTHERN P.LAINS WITH WESTERLY FLOW ACROSS THE NORTHERN PLAINS. H7 SHORTWAVE TROUGH HAS WEAKENED AND SHIFTED EAST...WITH ANOTHER H7 SHORTWAVE TROUGH OVER NORTHCENTRAL COLORADO. AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER OUR CWA...WITH A STATIONARY FRONT EXTENDING FROM NORTHEAST COLORADO ACROSS NORTHCENTRAL NEBRASKA. THIS AFTERNOON-TONIGHT...AS FIRST H7 TROUGH HAS WEAKENED AND SHIFTED EAST SUBSIDENCE HAS SPREAD INTO THE WESTERN PART OF THE FORECAST AREA WITH LOWER TD VALUES (UPPER 40S/LOWER 50S) ADVECTING INTO THE WESTERN PARTS OF THE FORECAST AREA. RESULT HAS BEEN CAPE VALUES DROPPING OFF SHARPLY AND SABLE AIR MOVING BACK OVER THE CWA. SHORT RANGE GUIDANCE CONTINUES TO KEEP HIGHER TD/CAPE VALUES IN OUR EASTERN CWA WITH ONLY 100-500 J/KG IN THE WEST THROUGH THE EVENING. CAPE VALUES AROUND 2000 J/KG ACROSS OUR EASTERN CWA COULD SUPPORT A FEW MARGINALLY SEVERE THUNDERSTORMS IF SOMETHING WAS TO DEVELOP ALONG WHAT IS LIKELY A DEVELOPING DRY LINE. NOT A LOT OF CONFIDENCE AND HI RES GUIDANCE HAS TRENDED AWAY FROM ADDITIONAL DEVELOPMENT IN OUR EAST. IT APPEARS THAT CHANCES ARE DECREASING FOR MOST OF THE CWA THIS AFTERNOON. THERE IS THE POSSIBILITY FOR A SHOWER OR THUNDERSTORM IN THE WESTERN CWA AS ANOTHER SHORTWAVE MOVES IN FROM THE WEST LATE THIS AFTERNOON THROUGH THIS EVENING...WITH BEST PRECIP SIGNAL IN THE SW. NOT A LOT OF CONFIDENCE AT THIS POINT IN COVERAGE...SO I DECIDED TO LIMIT POPS TO THE WEST THIS EVENING WITH A DOWNWARD TREND THROUGH 06Z. IT DOES APPEAR THAT HIGHER TD VALUES WILL BEGIN TO RECOVER OVERNIGHT FROM THE EAST/NORTHEAST WITH SURFACE HIGH PRESSURE/LOW LEVEL STABILITY SUPPORTING POSSIBLE FOG/STRATUS DEVELOPMENT. BASED ON SHORT RANGE GUIDANCE AND PERSISTENCE I KEPT HIGHER FOG COVERAGE (AREAS) LIMITED TO REPUBLICAN RIVER VALLEY IN SW NEBRASKA. MONDAY...GUIDANCE CONTINUES TO SHOW PRECIP SIGNAL LINGERING ACROSS THE SW PART OF OUR CWA. ANY SHORTWAVE TROUGHS/VORT MAXES ROTATING THROUGH PERIPHERY OF THE RIDGE APPEAR TO REMAIN SW OF OUR CWA WITH VERY LIMITED FORCING. INSTABILITY DOES BEGIN TO INCREASE SO IF ACTIVITY WAS TO DEVELOP TO THE WEST WE COULD SEE DEVELOPMENT TOWARDS THE SW PART OF OUR FORECAST AREA. I WASNT CONFIDENT ENOUGH TO INCREASE POPS DESPITE OVERLAPPING QPF FIELDS IN GUIDANCE...SO I LIMITED POPS TO 20/30 RANGE MONDAY AFTERNOON. HIGH TEMPS AS WITH THE LAST FEW DAYS WILL BE HIGHLY DEPENDENT ON MORNING STRATUS CLEARING WHICH IS CURRENTLY EXPECTED. RESULT SHOULD BE SEASONAL HIGHS IN THE UPPER 80S/AROUND 90. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 244 PM MDT SUN AUG 9 2015 FORECAST PROBLEM WILL BE CONTINUED THUNDERSTORM CHANCES. SATELLITE IS SHOWING AN AMPLIFIED AND MOSTLY PROGRESSIVE FLOW FROM THE PACIFIC INTO NORTH AMERICA. SOUTHERN UNITED STATES RIDGE REMAINS CENTERED OVER CENTRAL/EASTERN TEXAS. MODELS STARTED OUT FINE AT JET LEVEL. AT MID LEVELS...THE GFS/CANADIAN WERE INITIALLY DOING BETTER THAN THE REST OF THE OUT WITH THE NAM/SREF THE WORST OF THE REST OF THE BUNCH. THE SREF LOOKED LIKE IT WAS THE BEST AT THE SURFACE. IT LOOKED LIKE THE GFS...CANADIAN AND ECMWF WERE DOING THE BEST ON THE LOW LEVEL THERMAL FIELD AT THIS TIME. MONDAY NIGHT...LOW LEVEL UPSLOPE WINDS WILL BE IN PLACE THROUGH THE NIGHT AS SURFACE RIDGE NOSES DOWN INTO THE AREA. AS SHOWN THE LAST TWO DAYS...THE SHORTWAVE RIDGE AT 700 MB WILL SLOWLY MOVE TOWARD THE EAST THROUGH THE NIGHT AS A SHORTWAVE MOVES IN FROM THE WEST. MODELS HAVE SLOWED THINGS UP A LITTLE...AS HAS THE TREND BEEN THE LAST FEW DAYS AS WELL. THE GFS IS THE FURTHEST EAST WHICH IS NOT AN UCOMMON THING WHEN IT COMES TO BREAKING DOWN RIDGES TOO FAST. SO ONLY PROGRESSED THE POPS SLOWLY TO THE EAST THROUGH THE NIGHT. THE COMBINATION OF SLOW STORM MOVEMENT...PWS OF 1 TO 1.5 INCHES AND THE COMMON HEAVY RAIN SCENARIO OF A SHORTWAVE MOVING UP THE WEST SIDE OF A RIDGE COULD PRODUCE SOME LOCALIZED HEAVY RAINFALL. RAMPED THE AMOUNTS UP A LITTLE AND INCREASED THE INTENSITY OF THE RAINFALL AS WELL. THE BEST CHANCE FOR RAINFALL WILL BE IN THE SOUTHWEST THIRD TO HALF OF THE AREA. THIS PERIOD WILL NEED TO BE WASHED CLOSELY. TUESDAY/TUESDAY NIGHT...SLOWLY EVOLVING SITUATION THAT BEGINS MONDAY NIGHT...SLOWLY MOVING CONVECTIVELY INDUCED SYSTEM...CONTINUE THROUGH THIS ENTIRE PERIOD. MODELS ARE IN GOOD AGREEMENT ABOUT THIS. MORE THAN LIKELY SOME DEGREE OF CONVECTION WILL CONTINUE FROM THIS PREVIOUS THROUGH THIS ENTIRE PERIOD. AGAIN SAME HEAVY RAIN SCENARIO IS IN PLACE AS IN THE PREVIOUS PERIOD AND WILL HAVE TO BE WATCHED CLOSELY. ALSO THE SOUTHWEST THIRD TO HALF WILL HAVE THE BEST CHANCE OF RAINFALL...ESPECIALLY DURING THE DAY. THE AREA OF RAINFALL WILL SLOWLY MOVE TO THE SOUTH AND EAST DURING THE NIGHT. COMBINATION OF UPSLOPE SURFACE WINDS...LOTS OF CLOUD COVER AND ONGOING PRECIPITATION...WILL KEEP TEMPERATURES FROM WARMING UP TOO MUCH...ESPECIALLY IN THE SOUTHWEST HALF. SO LOWERED TEMPERATURES AROUND 5 DEGREES OR SO. THE COOLEST OUTPUT HAS TEMPERATURES COOLER THAN WHAT I HAVE THEM. WEDNESDAY...SLOW MOVING UPPER SYSTEM WILL KEEP RAINFALL AROUND THROUGH THE MORNING HOURS IN THE SOUTHEAST HALF. IF THERE IS ANY MORE SLOWLY...THE POPS WILL NEED TO BE RAISED. TEMPERATURES WILL BE A LITTLE WARMER BUT HOW MUCH WILL DEPEND ON HOW FAST THE SYSTEM AND ASSOCIATED CLOUDS/RAINFALL MOVE OUT OF THE AREA. AGAIN IF ANY MORE SLOWING TEMPERATURES WILL NEED TO BE LOWERED. WEDNESDAY NIGHT THROUGH SUNDAY...NOT TOO MUCH HAS CHANGED FROM WHAT THE MODELS HAVE BEEN DOING/SHOWING FROM THE LAST FEW DAYS. MODELS STILL DIFFER ON THE AMPLITUDED AND POSITION OF WHAT IS NOW THE SOUTHERN RIDGE THAT TRANSITIONS TO A MORE CENTERED WESTERN RIDGE. IN GENERAL UPPER RIDGE STAYS CENTERED NEAR THE FOUR CORNERS REGION. SINCE MUCH DOES CHANGE ALOFT...THE SURFACE ALSO DOES NOT CHANGE TOO MUCH. A SURFACE TROUGH OR LINGERING FRONTAL BOUNDARY STAYS NEAR OR OVER THE WESTERN PORTION OF THE AREA. FORECAST WILL HINGE ON SMALL IMPORTANT DETAILS THAT WILL BE HARD TO PIN DOWN AT THIS TIME SCALE. POSITION OF THE RIDGE SHOULD ALLOW SUBTROPICAL MOISTURE/WEAK SHORTWAVE TROUGHS TO ROTATE AROUND THE RIDGE INTO THE AREA. ALSO THE SURFACE BOUNDARY SHOULD HELP SET THUNDERSTORMS OFF. THERE WILL NOT BE HIGH PRECIPITATION CHANCES BUT HARD TO SAY THERE WILL NOT BE ANYTHING AT ALL. PER THE OVERNIGHT DISCUSSION/REASONING...THE WESTERN PORTION OF THE AREA WILL PROBABLY SEE THE BEST CHANCE DUE TO THE PROXIMITY OF THE SURFACE BOUNDARY. THE NEW CRH_INIT IS IN GOOD AGREEMENT WITH THE ABOVE MENTIONED SCENARIO/REASONING...SO ONCE AGAIN MADE NO CHANGES TO IT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 521 PM MDT SUN AUG 9 2015 VFR CONDITIONS ARE EXPECTED AT KGLD FOR THE NEXT 24 HOURS. KMCK WILL BE VFR BUT NOT FOR THE ENTIRE TIME. LATER TONIGHT BOUNDARY LAYER RH INCREASES TO 90 PERCENT OR MORE IN AN AREA INCLUDING KMCK. VFR CONDITIONS WILL RETURN TO KMCK BY MID MORNING. LATER MONDAY AFTERNOON THERE IS A SLIGHT CHANCE OF THUNDERSTORMS NEAR KGLD BUT WILL HOLD OFF MENTIONING VCTS DUE TO LATER TIMING OF STORMS INTO KGLD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
451 PM MDT SAT AUG 8 2015 .SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY) ISSUED AT 229 PM MDT SAT AUG 8 2015 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS 595 DM RIDGE ACROSS SOUTHERN PLAINS WITH PLUME OF PACIFIC MOISTURE STREAMING INTO THE CENTRAL ROCKIES AND ACROSS OUR CWA. SEVERAL WEAK RIPPLES/SHORTWAVE TROUGHS WITHIN THE H5/H7 SW FLOW ARE UPSTREAM OF THE REGION WITH SOME ENHANCEMENT ACROSS THE HIGHER TERRAIN IN THE CENTRAL AND SOUTHERN ROCKIES. AT THE SURFACE LOW PRESSURE EXTENDS ACROSS EASTERN COLORADO AND SOUTHWEST KANSAS. STATIONARY/WARM FRONT IS CURRENTLY JUST OVER THE SOUTHEAST PORTIONS OF OUR CWA. THIS AFTERNOON-TONIGHT...BAROCLINIC ZONE EXTENDING ACROSS SE CWA AND ACROSS EASTERN COLORADO WILL ACT AS FOCUS FOR INITIATION NEAR OUR CWA AS HEIGHT FALLS AND INCREASING ISENTROPIC ASCENT MOVES SOUTH OF INTERSTATE 70. STRONGEST PRECIP SIGNAL IS ALONG STATIONARY FRONT IN THE SOUTH...ESPECIALLY BY ARW/HRRR. RAP ANALYSIS SHOWS CAPE VALUES ALREADY AROUND 4000 J/KG IN THE SOUTHEAST...WITH EFFECTIVE BULK SHEER VALUES IN EXCESS OF 40KT. WHILE THERE IS SOME LOW LEVEL VEERING...OVERALL SEVERE INDICES FAVOR DAMAGING WINDS AND LARGE HAIL WITH ON A SMALL THREAT FOR TORNADOS WITHIN PROXIMITY TO MAIN TROUGH AXIS. VERY MOIST AIR MASS...THE POSSIBILITY FOR BACKBUILDING ALONG FRONTAL ZONE...AND STORM MOTIONS GENERALLY LESS THAN 20KT WILL TEND TO SUPPORT POTENTIAL FOR LOCALIZED FLASH FLOODING. HI RES GUIDANCE IS INDICATING POTENTIAL FOR THUNDERSTORMS TO FORM INTO ONE OR SEVERAL SMALL MCS CLUSTERS ACROSS THE SOUTHERN PART OF THE FORECAST AREA. EARLIER GUIDANCE WAS SHOWING THIS SPREADING AS FAR NORTH AS THE I-70 CORRIDOR. WITH LINGERING WAA ACROSS THE SE CWA...ALONG WITH SEVERAL MORE WEAK SHORTWAVES PASSING THROUGH THE REGION...SE PORTIONS OF THE FORECAST AREA COULD CONTINUE TO SEE SHOWER/THUNDERSTORM ACTIVITY LINGER THROUGH SUNDAY MORNING. TREND WILL BE FOR DECREASING INSTABILITY...SO SEVERE THREAT SHOULD BE LIMITED TO JUST THE EVENING HOURS. VERY MOIST AIR MASS AND LIGHT WINDS WILL ALSO TEND TO SUPPORT POTENTIAL FOR FOG/STRATUS TO REDEVELOP BY SUNRISE. SUNDAY...WITH WEAK FORCING AND LINGERING FRONT IN OUR SE...THERE WILL BE THE POTENTIAL FOR SHOWERS/THUNDERSTORMS THROUGH MIDDAY. NAM SHOWS INCREASING FORCING BY LATE MORNING EARLY AFTERNOON AS A STRONGER TROUGH DIGS INTO THE NORTHERN PLAINS. OTHER GUIDANCE IS NOT QUITE AS FAR SOUTH...PRIMARILY FAVORS THE SOUTHER PARTS OF OUR CWA FOR BEST THUNDERSTORM CHANCES. THERE SHOULD BE ENOUGH INSTABILITY/SHEER IN THE AFTERNOON TO SUPPORT AT LEAST A FEW MORE ORGANIZED THUNDERSTORMS. LOW CONFIDENCE IN HI TEMP FORECAST AS (LIKE TODAY) TEMPS WILL BE HIGHLY DEPENDENT ON STRATUS CLEARING AND TIMING OF THUNDERSTORM ACTIVITY. THE AIR MASS ADVERTISED OVER THE CWA WITH AVERAGE MIXING WOULD SUPPORT SEASONAL HIGHS IN THE UPPER 80S/LOWER 90S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 306 PM MDT SAT AUG 8 2015 FORECAST PROBLEM WILL BE CONTINUED THUNDERSTORM CHANCES. SATELLITE IS SHOWING AN AMPLIFIED AND MOSTLY PROGRESSIVE FLOW FROM THE PACIFIC INTO NORTH AMERICA. THIS FLOW BECOMES MORE OF A SPLIT WITH THE TROUGHS OVER THE WESTERN AND EASTERN PORTIONS OF THE COUNTRY. OLD CUTOFF LOW IS NOW BEING EJECTED INTO THE NORTH CENTRAL PORTION OF THE COUNTRY. MONSOONAL MOISTURE CONTINUES TO PULLED UP INTO THE REGION WITH EMBEDDED SHORTWAVE TROUGHS WITHIN THIS FLOW. AIR MASS REMAINS MOIST THROUGH A SIGNIFICANT DEPTH. AT JET LEVEL...THE GFS FOLLOWED BY THE NAM/CANADIAN WERE INITIALLY DOING THE BEST HERE. AT MID LEVELS...MODELS WERE CLOSE WITH THE GFS/CANADIAN/UKMET DOING SLIGHTLY BETTER. THE SREF AND NAM WERE DOING THE BEST ON THE SURFACE WIND AND PRESSURE FIELD. MODELS WERE HAVING A LITTLE TROUBLE ON THE LOW LEVEL THERMAL FIELD...THEY TENDED TO BE TOO COOL. OVERALL WOULD HAVE TO GIVE A SLIGHT EDGE TO THE NAM AND SREF. SUNDAY NIGHT...LOOKS LIKE SOME WEAK BOUNDARY SAGS SOUTH ACROSS THE AREA. MODELS ARE A LITTLE FASTER IN TAKING THE INITIAL SHORTWAVE THROUGH ALTHOUGH THERE IS NOT VERY GOOD AGREEMENT IN THAT. MODELS WANT TO BRING ANOTHER SHORTWAVE IN NORTHWEST FLOW DURING THE OVERNIGHT HOURS WITH ALSO NOT A LOT OF AGREEMENT. RIGHT REAR QUADRANT AFFECTS THE FAR NORTHERN PORTION OF THE AREA. WILL KEEP THE SLIGHT TO LOW CHANCE POPS WITH A GRADUAL DECREASE THROUGH THE NIGHT. LOOKS LIKE THERE WILL BE MAINLY STRATUS WITH NOT AS GOOD OF A CHANCE OF FOG. MONDAY/MONDAY NIGHT...RIDGE BEGINS TO BUILD INTO THE AREA WITH THE UPPER JET BEING PUSHED FURTHER NORTH AWAY FROM THE AREA. AREA IS IN POST FRONTAL UPSLOPE REGIME. RIDGING ALOFT LOOKS A LITTLE STRONGER AND FURTHER WEST DURING THE DAY THAN WAS SHOWN YESTERDAY SO WILL PUSH THE POPS FURTHER WEST. WILL HAVE SOME CLOUD COVER TO START THE DAY WITH A COOLER AIR MASS AND UPSLOPE WINDS PRESENT THROUGH THE DAY SO WILL DEFINITELY BE COOLER. 700 MB RIDGE MOVES A LITTLE TO THE EAST DURING THE NIGHT WITH INCREASING LIFT COMING IN FROM THE SOUTHWEST. SO POPS SHOULD STAY CONFINED TO THE SOUTHWEST HALF OF THE AREA WITH A GRADUAL INCREASE THROUGH WITH STORMS NOT MOVING VERY FAST. THAT COMBINED WITH HIGH PWS WILL SET THE STAGE MODERATE TO LOCALLY HEAVY RAINFALL. TUESDAY...ABOVE MENTIONED SHORTWAVE RIDGE AND TROUGH CONTINUE TO MOVE SLOWLY EAST THROUGH THE DAY. MOIST AIR MASS REMAIN IN PLACE WITH INCREASING LIFT. IT IS POSSIBLE THAT THERE COULD BE SOME PRECIPITATION AT THE BEGINNING AND THEN IT SHOULD GRADUALLY INCREASE IN COVERAGE AND INTENSITY. SO HAVE THE HIGHER POPS IN THE AFTERNOON. EASTERLY WINDS...CLOUD COVER AND DEVELOPING PRECIPITATION SHOULD KEEP TEMPERATURES SHOULD KEEP TEMPERATURES FROM WARMING VERY MUCH. TUESDAY NIGHT THROUGH SATURDAY...DETERMINISTIC AND ENSEMBLE OUTPUT IN BETTER AGREEMENT IN REGARDS TO THE EVOLUTION OF THE UPPER PATTERN. ESSENTIALLY MODELS BUILD THE RIDGE...NOW CENTERED TO OUR SOUTH...FURTHER TO THE WEST AND NORTH. THE DIFFERENCES INCREASE A LITTLE TOWARD THE END OF THE PERIOD BUT NOT AS BAD AS YESTERDAY. THE CENTER OF THE RIDGE WILL BE NEAR THE FOUR CORNERS REGION LEAVING A WEAKER NORTHERLY FLOW OVER THE AREA. IN THIS PATTERN WOULD ANTICIPATE THE SUBTROPICAL MOISTURE TO BE ABLE TO ROTATE AROUND THE RIDGE WITH WEAK/SUBTLE SHORTWAVES ROTATING AROUND IT. WPC PROGS SHOW A PERSISTENT FRONTAL BOUNDARY ALONG OR OVER THE WESTERN PORTION OF THE AREA UNTIL THE LAST DAY WHEN A DRY LINE/SURFACE TROUGH SETS UP IN THE SAME PLACE. WITH VERY SUBTLE FEATURES...I CANNOT RULE OUT CHANCES FOR THUNDERSTORMS ALMOST EVERY PERIOD. SO ANY SLIGHT CHANCE TO LOW CHANCE POPS TO DRY CONDITIONS DO NOT SEEM UNREASONABLE DEPENDING ON HOW THE DETAILS WORK OUT. SO ONCE AGAIN DID NOT MAKE ANY CHANGES TO WHAT THE CRH_INIT GAVE ME. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 440 PM MDT SAT AUG 8 2015 VFR CONDITIONS WILL CONTINUE THIS EVENING FOR KGLD AND KMCK. A SHORTWAVE MOVING THROUGH THE REGION WILL BRING A SLIGHT CHANCE OF A THUNDERSTORM TO KGLD THIS EVENING WITH A LESSER CHANCE AT KMCK. OVERNIGHT BOUNDARY LAYER MOISTURE INCREASES TO THE POINT THAT STRATUS AND FOG AND RESULTING MVFR CONDTIONS CAN BE EXPECTED AT KGLD. CIGS AT KMCK SHOULD NOT BE AS LOW AS KGLD BUT WILL STILL BE MVFR. VFR CONDITIONS RETURN BY LATE SUNDAY MORNING AND CONTINUE THROUGH THE AFTERNOON. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
309 PM MDT SAT AUG 8 2015 .SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY) ISSUED AT 229 PM MDT SAT AUG 8 2015 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS 595 DM RIDGE ACROSS SOUTHERN PLAINS WITH PLUME OF PACIFIC MOISTURE STREAMING INTO THE CENTRAL ROCKIES AND ACROSS OUR CWA. SEVERAL WEAK RIPPLES/SHORTWAVE TROUGHS WITHIN THE H5/H7 SW FLOW ARE UPSTREAM OF THE REGION WITH SOME ENHANCEMENT ACROSS THE HIGHER TERRAIN IN THE CENTRAL AND SOUTHERN ROCKIES. AT THE SURFACE LOW PRESSURE EXTENDS ACROSS EASTERN COLORADO AND SOUTHWEST KANSAS. STATIONARY/WARM FRONT IS CURRENTLY JUST OVER THE SOUTHEAST PORTIONS OF OUR CWA. THIS AFTERNOON-TONIGHT...BAROCLINIC ZONE EXTENDING ACROSS SE CWA AND ACROSS EASTERN COLORADO WILL ACT AS FOCUS FOR INITIATION NEAR OUR CWA AS HEIGHT FALLS AND INCREASING ISENTROPIC ASCENT MOVES SOUTH OF INTERSTATE 70. STRONGEST PRECIP SIGNAL IS ALONG STATIONARY FRONT IN THE SOUTH...ESPECIALLY BY ARW/HRRR. RAP ANALYSIS SHOWS CAPE VALUES ALREADY AROUND 4000 J/KG IN THE SOUTHEAST...WITH EFFECTIVE BULK SHEER VALUES IN EXCESS OF 40KT. WHILE THERE IS SOME LOW LEVEL VEERING...OVERALL SEVERE INDICES FAVOR DAMAGING WINDS AND LARGE HAIL WITH ON A SMALL THREAT FOR TORNADOS WITHIN PROXIMITY TO MAIN TROUGH AXIS. VERY MOIST AIR MASS...THE POSSIBILITY FOR BACKBUILDING ALONG FRONTAL ZONE...AND STORM MOTIONS GENERALLY LESS THAN 20KT WILL TEND TO SUPPORT POTENTIAL FOR LOCALIZED FLASH FLOODING. HI RES GUIDANCE IS INDICATING POTENTIAL FOR THUNDERSTORMS TO FORM INTO ONE OR SEVERAL SMALL MCS CLUSTERS ACROSS THE SOUTHERN PART OF THE FORECAST AREA. EARLIER GUIDANCE WAS SHOWING THIS SPREADING AS FAR NORTH AS THE I-70 CORRIDOR. WITH LINGERING WAA ACROSS THE SE CWA...ALONG WITH SEVERAL MORE WEAK SHORTWAVES PASSING THROUGH THE REGION...SE PORTIONS OF THE FORECAST AREA COULD CONTINUE TO SEE SHOWER/THUNDERSTORM ACTIVITY LINGER THROUGH SUNDAY MORNING. TREND WILL BE FOR DECREASING INSTABILITY...SO SEVERE THREAT SHOULD BE LIMITED TO JUST THE EVENING HOURS. VERY MOIST AIR MASS AND LIGHT WINDS WILL ALSO TEND TO SUPPORT POTENTIAL FOR FOG/STRATUS TO REDEVELOP BY SUNRISE. SUNDAY...WITH WEAK FORCING AND LINGERING FRONT IN OUR SE...THERE WILL BE THE POTENTIAL FOR SHOWERS/THUNDERSTORMS THROUGH MIDDAY. NAM SHOWS INCREASING FORCING BY LATE MORNING EARLY AFTERNOON AS A STRONGER TROUGH DIGS INTO THE NORTHERN PLAINS. OTHER GUIDANCE IS NOT QUITE AS FAR SOUTH...PRIMARILY FAVORS THE SOUTHER PARTS OF OUR CWA FOR BEST THUNDERSTORM CHANCES. THERE SHOULD BE ENOUGH INSTABILITY/SHEER IN THE AFTERNOON TO SUPPORT AT LEAST A FEW MORE ORGANIZED THUNDERSTORMS. LOW CONFIDENCE IN HI TEMP FORECAST AS (LIKE TODAY) TEMPS WILL BE HIGHLY DEPENDENT ON STRATUS CLEARING AND TIMING OF THUNDERSTORM ACTIVITY. THE AIR MASS ADVERTISED OVER THE CWA WITH AVERAGE MIXING WOULD SUPPORT SEASONAL HIGHS IN THE UPPER 80S/LOWER 90S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 306 PM MDT SAT AUG 8 2015 FORECAST PROBLEM WILL BE CONTINUED THUNDERSTORM CHANCES. SATELLITE IS SHOWING AN AMPLIFIED AND MOSTLY PROGRESSIVE FLOW FROM THE PACIFIC INTO NORTH AMERICA. THIS FLOW BECOMES MORE OF A SPLIT WITH THE TROUGHS OVER THE WESTERN AND EASTERN PORTIONS OF THE COUNTRY. OLD CUTOFF LOW IS NOW BEING EJECTED INTO THE NORTH CENTRAL PORTION OF THE COUNTRY. MONSOONAL MOISTURE CONTINUES TO PULLED UP INTO THE REGION WITH EMBEDDED SHORTWAVE TROUGHS WITHIN THIS FLOW. AIR MASS REMAINS MOIST THROUGH A SIGNIFICANT DEPTH. AT JET LEVEL...THE GFS FOLLOWED BY THE NAM/CANADIAN WERE INITIALLY DOING THE BEST HERE. AT MID LEVELS...MODELS WERE CLOSE WITH THE GFS/CANADIAN/UKMET DOING SLIGHTLY BETTER. THE SREF AND NAM WERE DOING THE BEST ON THE SURFACE WIND AND PRESSURE FIELD. MODELS WERE HAVING A LITTLE TROUBLE ON THE LOW LEVEL THERMAL FIELD...THEY TENDED TO BE TOO COOL. OVERALL WOULD HAVE TO GIVE A SLIGHT EDGE TO THE NAM AND SREF. SUNDAY NIGHT...LOOKS LIKE SOME WEAK BOUNDARY SAGS SOUTH ACROSS THE AREA. MODELS ARE A LITTLE FASTER IN TAKING THE INITIAL SHORTWAVE THROUGH ALTHOUGH THERE IS NOT VERY GOOD AGREEMENT IN THAT. MODELS WANT TO BRING ANOTHER SHORTWAVE IN NORTHWEST FLOW DURING THE OVERNIGHT HOURS WITH ALSO NOT A LOT OF AGREEMENT. RIGHT REAR QUADRANT AFFECTS THE FAR NORTHERN PORTION OF THE AREA. WILL KEEP THE SLIGHT TO LOW CHANCE POPS WITH A GRADUAL DECREASE THROUGH THE NIGHT. LOOKS LIKE THERE WILL BE MAINLY STRATUS WITH NOT AS GOOD OF A CHANCE OF FOG. MONDAY/MONDAY NIGHT...RIDGE BEGINS TO BUILD INTO THE AREA WITH THE UPPER JET BEING PUSHED FURTHER NORTH AWAY FROM THE AREA. AREA IS IN POST FRONTAL UPSLOPE REGIME. RIDGING ALOFT LOOKS A LITTLE STRONGER AND FURTHER WEST DURING THE DAY THAN WAS SHOWN YESTERDAY SO WILL PUSH THE POPS FURTHER WEST. WILL HAVE SOME CLOUD COVER TO START THE DAY WITH A COOLER AIR MASS AND UPSLOPE WINDS PRESENT THROUGH THE DAY SO WILL DEFINITELY BE COOLER. 700 MB RIDGE MOVES A LITTLE TO THE EAST DURING THE NIGHT WITH INCREASING LIFT COMING IN FROM THE SOUTHWEST. SO POPS SHOULD STAY CONFINED TO THE SOUTHWEST HALF OF THE AREA WITH A GRADUAL INCREASE THROUGH WITH STORMS NOT MOVING VERY FAST. THAT COMBINED WITH HIGH PWS WILL SET THE STAGE MODERATE TO LOCALLY HEAVY RAINFALL. TUESDAY...ABOVE MENTIONED SHORTWAVE RIDGE AND TROUGH CONTINUE TO MOVE SLOWLY EAST THROUGH THE DAY. MOIST AIR MASS REMAIN IN PLACE WITH INCREASING LIFT. IT IS POSSIBLE THAT THERE COULD BE SOME PRECIPITATION AT THE BEGINNING AND THEN IT SHOULD GRADUALLY INCREASE IN COVERAGE AND INTENSITY. SO HAVE THE HIGHER POPS IN THE AFTERNOON. EASTERLY WINDS...CLOUD COVER AND DEVELOPING PRECIPITATION SHOULD KEEP TEMPERATURES SHOULD KEEP TEMPERATURES FROM WARMING VERY MUCH. TUESDAY NIGHT THROUGH SATURDAY...DETERMINISTIC AND ENSEMBLE OUTPUT IN BETTER AGREEMENT IN REGARDS TO THE EVOLUTION OF THE UPPER PATTERN. ESSENTIALLY MODELS BUILD THE RIDGE...NOW CENTERED TO OUR SOUTH...FURTHER TO THE WEST AND NORTH. THE DIFFERENCES INCREASE A LITTLE TOWARD THE END OF THE PERIOD BUT NOT AS BAD AS YESTERDAY. THE CENTER OF THE RIDGE WILL BE NEAR THE FOUR CORNERS REGION LEAVING A WEAKER NORTHERLY FLOW OVER THE AREA. IN THIS PATTERN WOULD ANTICIPATE THE SUBTROPICAL MOISTURE TO BE ABLE TO ROTATE AROUND THE RIDGE WITH WEAK/SUBTLE SHORTWAVES ROTATING AROUND IT. WPC PROGS SHOW A PERSISTENT FRONTAL BOUNDARY ALONG OR OVER THE WESTERN PORTION OF THE AREA UNTIL THE LAST DAY WHEN A DRY LINE/SURFACE TROUGH SETS UP IN THE SAME PLACE. WITH VERY SUBTLE FEATURES...I CANNOT RULE OUT CHANCES FOR THUNDERSTORMS ALMOST EVERY PERIOD. SO ANY SLIGHT CHANCE TO LOW CHANCE POPS TO DRY CONDITIONS DO NOT SEEM UNREASONABLE DEPENDING ON HOW THE DETAILS WORK OUT. SO ONCE AGAIN DID NOT MAKE ANY CHANGES TO WHAT THE CRH_INIT GAVE ME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1139 AM MDT SAT AUG 8 2015 1500-2500 KFT STRATUS SHOULD CLEAR BY THE VALID TAF PERIOD AT KGLD. SHORT RANGE GUIDANCE AND SATELLITE TRENDS INDICATE THIS SHOULD WILL LINGER AT KMCK THROUGH THE EARLY AFTERNOON BEFORE LIFTING. SCATTERED THUNDERSTORM WILL DEVELOP MAINLY SOUTH OF INTERSTATE 70...WITH ACTIVITY MOVING WITHIN THE VICINITY OF KGLD AFTER 00Z. NOT A LOT OF CONFIDENCE COVERAGE AT KGLD WILL NECESSITATE MORE THAN VCTS MENTION AT THIS POINT...SO WE WILL NEED TO MONITOR TRENDS AS THUNDERSTORMS INITIATE SOUTH AND TRACK NORTHEAST. WITH VERY MOIST AIR MASS IN PLACE EXPECT STRATUS/FOG TO REDEVELOP 09-10Z. THERE IS A POSSIBILITY BASED ON HI RES GUIDANCE OF VLIFR CONDITIONS AROUND 12Z AT KGLD AND KMCK...HOWEVER GUIDANCE ISNT SHOWING A LOT OF CONSISTENCY AND IT MAY END UP BEING MORE OF A TEMPORARY CONDITION. IN ANY CASE STRATUS/FOG SHOULD CLEAR WITH RISING SUN MID MORNING SUNDAY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
229 PM MDT SAT AUG 8 2015 .SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY) ISSUED AT 229 PM MDT SAT AUG 8 2015 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS 595 DM RIDGE ACROSS SOUTHERN PLAINS WITH PLUME OF PACIFIC MOISTURE STREAMING INTO THE CENTRAL ROCKIES AND ACROSS OUR CWA. SEVERE WEAK RIPPLES/SHORTWAVE TROUGHS WITHIN THE H5/H7 SW FLOW ARE UPSTREAM OF THE REGION WITH SOME ENHANCEMENT ACROSS THE HIGHER TERRAIN IN THE CENTRAL AND SOUTHERN ROCKIES. AT THE SURFACE LOW PRESSURE EXTENDS ACROSS EASTERN COLORADO AND SOUTHWEST KANSAS. STATIONARY/WARM FRONT IS CURRENTLY JUST OVER THE SOUTHEAST PORTIONS OF OUR CWA. THIS AFTERNOON-TONIGHT...BAROCLINIC ZONE EXTENDING ACROSS SE CWA AND ACROSS EASTERN COLORADO WILL ACT AS FOCUS FOR INITIATION NEAR OUR CWA AS HEIGHT FALLS AND INCREASING ISENTROPIC ASCENT MOVES SOUTH OF INTERSTATE 70. STRONGEST PRECIP SIGNAL IS ALONG STATIONARY FRONT IN THE SOUTH...ESPECIALLY BY ARW/HRRR. RAP ANALYSIS SHOWS CAPE VALUES ALREADY AROUND 4000 J/KG IN THE SOUTHEAST...WITH EFFECTIVE BULK SHEER VALUES IN EXCESS OF 40KT. WHILE THERE IS SOME LOW LEVEL VEERING...OVERALL SEVERE INDICES FAVOR DAMAGING WINDS AND LARGE HAIL WITH ON A SMALL THREAT FOR TORNADOS WITHIN PROXIMITY TO MAIN TROUGH AXIS. VERY MOIST AIR MASS...THE POSSIBILITY FOR BACKBUILDING ALONG FRONTAL ZONE...AND STORM MOTIONS GENERALLY LESS THAN 20KT WILL TEND TO SUPPORT POTENTIAL FOR LOCALIZED FLASH FLOODING. HI RES GUIDANCE IS INDICATING POTENTIAL FOR THUNDERSTORMS TO FORM INTO ONE OR SEVERAL SMALL MCS CLUSTERS ACROSS THE SOUTHERN PART OF THE FORECAST AREA. EARLIER GUIDANCE WAS SHOWING THIS SPREADING AS FAR NORTH AS THE I-70 CORRIDOR. WITH LINGERING WAA ACROSS THE SE CWA...ALONG WITH SEVERAL MORE WEAK SHORTWAVES PASSING THROUGH THE REGION...SE PORTIONS OF THE FORECAST AREA COULD CONTINUE TO SEE SHOWER/THUNDERSTORM ACTIVITY LINGER THROUGH SUNDAY MORNING. TREND WILL BE FOR DECREASING INSTABILITY...SO SEVERE THREAT SHOULD BE LIMITED TO JUST THE EVENING HOURS. VERY MOIST AIR MASS AND LIGHT WINDS WILL ALSO TEND TO SUPPORT POTENTIAL FOR FOG/STRATUS TO REDEVELOP BY SUNRISE. SUNDAY...WITH WEAK FORCING AND LINGERING FRONT IN OUR SE...THERE WILL BE THE POTENTIAL FOR SHOWERS/THUNDERSTORMS THROUGH MIDDAY. NAM SHOWS INCREASING FORCING BY LATE MORNING EARLY AFTERNOON AS A STRONGER TROUGH DIGS INTO THE NORTHERN PLAINS. OTHER GUIDANCE IS NOT QUITE AS FAR SOUTH...PRIMARILY FAVORS THE SOUTHER PARTS OF OUR CWA FOR BEST THUNDERSTORM CHANCES. THERE SHOULD BE ENOUGH INSTABILITY/SHEER IN THE AFTERNOON TO SUPPORT AT LEAST A FEW MORE ORGANIZED THUNDERSTORMS. LOW CONFIDENCE IN HI TEMP FORECAST AS (LIKE TODAY) TEMPS WILL BE HIGHLY DEPENDENT ON STRATUS CLEARING AND TIMING OF THUNDERSTORM ACTIVITY. THE AIR MASS ADVERTISED OVER THE CWA WITH AVERAGE MIXING WOULD SUPPORT SEASONAL HIGHS IN THE UPPER 80S/LOWER 90S. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 222 AM MDT SAT AUG 8 2015 AN UPPER LEVEL RIDGE WILL BE IN PLACE OVER THE TRI STATE AREA TO START OFF THE LONG TERM PERIOD TUESDAY. THE CENTRAL AREA OF HIGH PRESSURE WILL CONTINUE TO RETROGRADE AND INCREASE IN AMPLITUDE OVER THE ROCKY MOUNTAIN RANGE AND THE NORTHERN PLAINS WEDNESDAY. WITH THE PRESENCE OF THE UPPER RIDGE...JET AREAS AND POCKETS OF VORTICITY WILL REMAIN WELL AWAY FROM THE TRI STATE AREA...WHICH WILL BRING UPPER STABILITY FOR THE REST OF THE FORECAST PERIOD. AT THE SURFACE...A COOLER AIR MASS WITH A SURFACE HIGH PRESSURE FILTERING INTO THE PLAINS BEHIND A COLD FRONTAL PASSAGE WILL BRING COOLER HIGH TEMPERATURES IN THE MID TO UPPER 80S ON TUESDAY. ON THE FRONT SIDE OF THE HIGH PRESSURE SYSTEM...EASTERLY UPSLOPE FLOW WILL BRING MOISTURE INTO THE HIGH PLAINS DURING THE MORNING HOURS BEFORE SURFACE WINDS SHIFT TO THE SOUTH/SOUTHEAST. GFS/ECMWF HINT AT A SURFACE DRY LINE POSITIONED MORE ALONG THE SOUTHWESTERN PORTION OF THE FORECAST AREA...SO THUNDERSTORMS LOOK MORE LIKELY TO FORM ALONG THE VICINITY OF THE FORECAST AREA ALONG THIS BOUNDARY. A DEVELOPING SURFACE TROUGH IN EASTERN COLORADO MAY ALLOW STORMS TO DEVELOP ELSEWHERE WITH CAPE AND MOISTURE PROFILES SUFFICIENT ENOUGH FOR DEVELOPMENT. THE UPPER LEVEL HIGH WILL THEN MOVE AND BECOME POSITIONED DIRECTLY OVER THE TRI STATE AREA FOR THE END OF THE COMING WEEK...WHICH WILL DRY OUT CONDITIONS WITH A LACK OF UPPER OR SURFACE FORCING. EXPECTING TEMPERATURES IN THE LOW TO MID 90S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1139 AM MDT SAT AUG 8 2015 1500-2500 KFT STRATUS SHOULD CLEAR BY THE VALID TAF PERIOD AT KGLD. SHORT RANGE GUIDANCE AND SATELLITE TRENDS INDICATE THIS SHOULD WILL LINGER AT KMCK THROUGH THE EARLY AFTERNOON BEFORE LIFTING. SCATTERED THUNDERSTORM WILL DEVELOP MAINLY SOUTH OF INTERSTATE 70...WITH ACTIVITY MOVING WITHIN THE VICINITY OF KGLD AFTER 00Z. NOT A LOT OF CONFIDENCE COVERAGE AT KGLD WILL NECESSITATE MORE THAN VCTS MENTION AT THIS POINT...SO WE WILL NEED TO MONITOR TRENDS AS THUNDERSTORMS INITIATE SOUTH AND TRACK NORTHEAST. WITH VERY MOIST AIR MASS IN PLACE EXPECT STRATUS/FOG TO REDEVELOP 09-10Z. THERE IS A POSSIBILITY BASED ON HI RES GUIDANCE OF VLIFR CONDITIONS AROUND 12Z AT KGLD AND KMCK...HOWEVER GUIDANCE ISNT SHOWING A LOT OF CONSISTENCY AND IT MAY END UP BEING MORE OF A TEMPORARY CONDITION. IN ANY CASE STRATUS/FOG SHOULD CLEAR WITH RISING SUN MID MORNING SUNDAY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...MK AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
501 AM CDT SAT AUG 8 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 501 AM CDT SAT AUG 8 2015 THUNDERSTORMS WERE MOVING ACROSS NORTH CENTRAL AND NORTHEAST KANSAS THIS MORNING AT 09Z. THE LOW LEVEL JET HAS HELPED TO MAINTAIN THE CONVECTION AS IT MOVES ACROSS THE CWA THIS MORNING. THE STORMS ARE EXPECTED TO MOVE ACROSS NORTHEAST AND EAST CENTRAL KANSAS THIS MORNING. THIS MAY COMPLICATE THE TEMPERATURE FORECAST FOR LATER TODAY, BUT FOR NOW WILL CONTINUE WITH TEMPERATURES REACHING THE LOWER 90S NEAR THE NEBRASKA BORDER TO AROUND 100 NEAR CENTRAL KANSAS. AFTERNOON HEAT INDICES WILL RANGE FROM 105 TO 109 AND WILL KEEP THE HEAT ADVISORY GOING AS IS FOR TODAY. THUNDERSTORMS ARE FORECAST TO REDEVELOP THIS AFTERNOON AND EVENING NEAR A SURFACE TROUGH ACROSS SOUTHERN NEBRASKA AND BUILD SOUTHWEST INTO NORTH CENTRAL KANSAS. A WAVE IS EXPECTED TO MOVE ACROSS NEBRASKA AND NORTHERN KANSAS THIS EVENING AND INTO MISSOURI AND IOWA BY SUNDAY MORNING. SHEAR AND INSTABILITY WILL BE FAVORABLE FOR STRONG TO SEVERE CONVECTION AND WIND PROFILES SHOWING LARGE LOOPED HODOGRAPHS, SO EXPECT LARGE HAIL, DAMAGING WINDS AND A POSSIBLE TORNADO AS THE MAIN HAZARDS. HIGH MOISTURE CONTENT IN THE ATMOSPHERE WILL LEAD TO RAINFALL RATES NEAR 2 INCHES PER HOUR WHICH MAY LEAD TO FLASH FLOODING. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 501 AM CDT SAT AUG 8 2015 EARLY MORNING SUNDAY A SHORTWAVE IS EXPECTED TO MOVE ACROSS EASTERN NEBRASKA AND INTO IOWA WHILE A SURFACE FRONT EXTENDS ACROSS THE FORECAST AREA. EXPECT SCATTERED THUNDERSTORMS MAY BE ONGOING TO START THE MORNING BEFORE MOVING OFF TO THE EAST. THE FRONTAL BOUNDARY IS EXPECTED TO MOVE INTO EAST CENTRAL KANSAS GENERALLY SOUTH OF INTERSTATE 35 BY LATE AFTERNOON. ANOTHER WAVE WILL EJECT OUT OF THE ROCKIES AND MOVE ACROSS NORTHERN KANSAS IN THE AFTERNOON AND THEN PHASE WITH A LONGER WAVELENGTH TROUGH DROPPING SOUTHEAST FROM THE NORTHERN PLAINS SUNDAY NIGHT. MOISTURE WILL POOL NEAR AND SOUTH OF THE BOUNDARY AS PRECIPITABLE WATER VALUES REMAIN AROUND TWO INCHES. EXPECT ANOTHER ROUND OF STORMS TO DEVELOP NEAR THE BOUNDARY WITH ELEVATED STORMS TO THE NORTH. LOW LEVEL JET WILL INCREASE ISENTROPIC LIFT TO THE NORTH OF THE BOUNDARY INITIALLY, BEFORE VEERING TO THE SOUTHWEST BY MONDAY MORNING. SHEAR AND INSTABILITY WILL BE SUPPORTIVE OF A FEW STRONG STORMS SUNDAY AFTERNOON AND SUNDAY NIGHT. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE ESPECIALLY ACROSS EAST CENTRAL KANSAS. THE UPPER TROUGH WILL MOVE OFF TO THE EAST BRINING AN END TO PRECIPITATION DURING THE DAY. THE UPPER RIDGE THEN AMPLIFIES ACROSS THE ROCKIES INTO CENTRAL CANADA AND SHARPENS IN THE TUESDAY THROUGH FRIDAY TIME PERIOD. SURFACE HIGH PRESSURE WILL SLIDE INTO THE CENTRAL PLAINS AND REMAIN FOR MUCH OF THE TUESDAY THROUGH FRIDAY TIME PERIOD. UPSLOPE CONVECTION ALONG THE FRONT RANGE AND HIGH PLAINS IS EXPECTED TO REMAIN TO THE WEST OF THE FORECAST AREA SO WILL MAINTAIN A DRY FORECAST. TEMPERATURES SUNDAY WILL WARM INTO THE LOWER TO MID 90S SOUTH OF THE FRONT WITH MID 80S NEAR THE NEBRASKA BORDER. AFTERNOON HEAT INDICES IN EAST CENTRAL KANSAS WILL TOP OUT IN THE 100 TO 102 DEGREE RANGE. BELOW NORMAL TEMPERATURES IN THE 80S ARE EXPECTED FOR THE REST OF THE PERIOD WITH LOWS IN THE 60S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1135 PM CDT FRI AUG 7 2015 THERE IS QUITE A BIT OF UNCERTAINTY IN WHERE THE MCS WILL GO DURING THE EARLY MORNING HOURS. THE HRRR HAS BEEN CONSISTENTLY BRINGING THE ELEVATED STORMS THROUGH EASTERN KS, ALTHOUGH IT SEEMS TO BE DELAYING THE PROGRESS TO MORE MID MORNING. MEANWHILE THE OPERATIONAL MODELS CONTINUE TO FOCUS THE MOST LIKELY TRACK OF THE STORMS ACROSS SOUTHERN NEB AND FAR NORTHERN KS. WITH PROFILER DATA SHOWING THE DECENT LOW LEVEL JET VEERING TO THE SOUTH AND SOUTHWEST, THINK THERE IS A CHANCE FOR ELEVATED STORMS TO MOVE INTO THE TERMINALS SO WILL INCLUDE A VCTS WITH VFR CONDITIONS AND MONITOR TRENDS. && .TOP WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR KSZ010>012-021>024-026-034>040-054>056-058-059. && $$ SHORT TERM...65/53 LONG TERM...53 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
223 AM MDT SAT AUG 8 2015 .UPDATE... ISSUED AT 1018 PM MDT FRI AUG 7 2015 UPDATE SENT TO CANCEL SEVERE THUNDERSTORM WATCH FOR THE ENTIRE AREA. SEVERE THREAT HAS SHIFTED EAST OF THE CWA...BUT DO EXPECT SCATTERED RW/TRW TO PERSIST BUT TAPER AS THE OVERNIGHT HRS PROGRESS. FLASH FLOOD WARNING REMAINS IN EFFECT FOR HITCHCOCK COUNTY IN NEBRASKA. CONCERN IS FOR HEAVY RAINFALL THAT OCCURRED JUST TO THE NORTH EARLIER THIS EVENING IN CHASE/HAYS COUNTIES... WILL FILTER SOUTH VIA THE FRENCHMEN CREEK AND AFFECT AREAS LIKE STRATTON...CULBERTSON. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 159 PM MDT FRI AUG 7 2015 BIGGEST CHALLENGE IN SHORT TERM IS THUNDERSTORM POTENTIAL THIS AFTERNOON AND OVERNIGHT. NUMEROUS RUNS OF THE RAP PERSIST IN BREAKING OUT SCATTERED AFTERNOON CONVECTION ACROSS THE CENTRAL AND NORTHEAST COUNTIES...GENERALLY IN THE VICINITY OF A VERY WEAK DECAYING SURFACE BOUNDARY. HAVE SOME DOUBTS ABOUT THIS LOOKING AT CURRENT SATELLITE TRENDS AND SPC MESOANALYSIS CINH...BUT HAVE LEFT THE SLIGHT CHANCE POPS NONETHELESS. BIGGER ISSUE IS DEVELOPMENT OF STORMS OVER COLORADO LATER THIS AFTERNOON AND THEIR SUBSEQUENT MOVEMENT. WATER VAPOR IMAGERY SHOWS THE APPROACH OF THE NEXT UPSTREAM SHORTWAVE TROUGH AND RADAR NOW SHOWS INITIAL THUNDERSTORM DEVELOPMENT SOUTH OF DENVER. MOST GUIDANCE...INCLUDING THE CONVECTION-ALLOWING MODELS...INDICATES BEST COVERAGE OF STORMS WILL BE ACROSS NORTHEAST COLORADO INTO SOUTHWEST NEBRASKA...CLIPPING NORTHWEST KANSAS WITH LESSER COVERAGE SOUTH AND EAST. ULTIMATELY IT DEPENDS ON UPSCALE DEVELOPMENT AND WHETHER OR NOT A DECENT MCS CAN DEVELOP AND PRODUCE STORMS FURTHER SOUTHEAST OF THE MAIN SHORTWAVE. HAVE CONTINUED THE PREVIOUS FORECAST TREND OF BEST COVERAGE NORTH AND NORTHWEST WITH LESSER POTENTIAL SOUTH OF I-70. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 222 AM MDT SAT AUG 8 2015 AN UPPER LEVEL RIDGE WILL BE IN PLACE OVER THE TRI STATE AREA TO START OFF THE LONG TERM PERIOD TUESDAY. THE CENTRAL AREA OF HIGH PRESSURE WILL CONTINUE TO RETROGRADE AND INCREASE IN AMPLITUDE OVER THE ROCKY MOUNTAIN RANGE AND THE NORTHERN PLAINS WEDNESDAY. WITH THE PRESENCE OF THE UPPER RIDGE...JET AREAS AND POCKETS OF VORTICITY WILL REMAIN WELL AWAY FROM THE TRI STATE AREA...WHICH WILL BRING UPPER STABILITY FOR THE REST OF THE FORECAST PERIOD. AT THE SURFACE...A COOLER AIR MASS WITH A SURFACE HIGH PRESSURE FILTERING INTO THE PLAINS BEHIND A COLD FRONTAL PASSAGE WILL BRING COOLER HIGH TEMPERATURES IN THE MID TO UPPER 80S ON TUESDAY. ON THE FRONT SIDE OF THE HIGH PRESSURE SYSTEM...EASTERLY UPSLOPE FLOW WILL BRING MOISTURE INTO THE HIGH PLAINS DURING THE MORNING HOURS BEFORE SURFACE WINDS SHIFT TO THE SOUTH/SOUTHEAST. GFS/ECMWF HINT AT A SURFACE DRY LINE POSITIONED MORE ALONG THE SOUTHWESTERN PORTION OF THE FORECAST AREA...SO THUNDERSTORMS LOOK MORE LIKELY TO FORM ALONG THE VICINITY OF THE FORECAST AREA ALONG THIS BOUNDARY. A DEVELOPING SURFACE TROUGH IN EASTERN COLORADO MAY ALLOW STORMS TO DEVELOP ELSEWHERE WITH CAPE AND MOISTURE PROFILES SUFFICIENT ENOUGH FOR DEVELOPMENT. THE UPPER LEVEL HIGH WILL THEN MOVE AND BECOME POSITIONED DIRECTLY OVER THE TRI STATE AREA FOR THE END OF THE COMING WEEK...WHICH WILL DRY OUT CONDITIONS WITH A LACK OF UPPER OR SURFACE FORCING. EXPECTING TEMPERATURES IN THE LOW TO MID 90S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1114 PM MDT FRI AUG 7 2015 SCATTERED SHOWERS AND 6SM IN FOG WILL GIVE WAY TO 1SM OR LESS IN FOG BY 10Z SATURDAY THRU 14Z-15Z...WITH CEILINGS OVC010 OR LESS. FROM 14Z-15Z ONWARD...VFR CONDITIONS WITH SCT050-150. WINDS WILL HAVE VARYING DIRECTION THRU FORECAST PERIOD WITH 5-15KTS RANGE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JN SHORT TERM...DLF LONG TERM...MK AVIATION...JN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1114 PM MDT FRI AUG 7 2015 .UPDATE... ISSUED AT 1018 PM MDT FRI AUG 7 2015 UPDATE SENT TO CANCEL SEVERE THUNDERSTORM WATCH FOR THE ENTIRE AREA. SEVERE THREAT HAS SHIFTED EAST OF THE CWA...BUT DO EXPECT SCATTERED RW/TRW TO PERSIST BUT TAPER AS THE OVERNIGHT HRS PROGRESS. FLASH FLOOD WARNING REMAINS IN EFFECT FOR HITCHCOCK COUNTY IN NEBRASKA. CONCERN IS FOR HEAVY RAINFALL THAT OCCURRED JUST TO THE NORTH EARLIER THIS EVENING IN CHASE/HAYS COUNTIES... WILL FILTER SOUTH VIA THE FRENCHMEN CREEK AND AFFECT AREAS LIKE STRATTON...CULBERTSON. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 159 PM MDT FRI AUG 7 2015 BIGGEST CHALLENGE IN SHORT TERM IS THUNDERSTORM POTENTIAL THIS AFTERNOON AND OVERNIGHT. NUMEROUS RUNS OF THE RAP PERSIST IN BREAKING OUT SCATTERED AFTERNOON CONVECTION ACROSS THE CENTRAL AND NORTHEAST COUNTIES...GENERALLY IN THE VICINITY OF A VERY WEAK DECAYING SURFACE BOUNDARY. HAVE SOME DOUBTS ABOUT THIS LOOKING AT CURRENT SATELLITE TRENDS AND SPC MESOANALYSIS CINH...BUT HAVE LEFT THE SLIGHT CHANCE POPS NONETHELESS. BIGGER ISSUE IS DEVELOPMENT OF STORMS OVER COLORADO LATER THIS AFTERNOON AND THEIR SUBSEQUENT MOVEMENT. WATER VAPOR IMAGERY SHOWS THE APPROACH OF THE NEXT UPSTREAM SHORTWAVE TROUGH AND RADAR NOW SHOWS INITIAL THUNDERSTORM DEVELOPMENT SOUTH OF DENVER. MOST GUIDANCE...INCLUDING THE CONVECTION-ALLOWING MODELS...INDICATES BEST COVERAGE OF STORMS WILL BE ACROSS NORTHEAST COLORADO INTO SOUTHWEST NEBRASKA...CLIPPING NORTHWEST KANSAS WITH LESSER COVERAGE SOUTH AND EAST. ULTIMATELY IT DEPENDS ON UPSCALE DEVELOPMENT AND WHETHER OR NOT A DECENT MCS CAN DEVELOP AND PRODUCE STORMS FURTHER SOUTHEAST OF THE MAIN SHORTWAVE. HAVE CONTINUED THE PREVIOUS FORECAST TREND OF BEST COVERAGE NORTH AND NORTHWEST WITH LESSER POTENTIAL SOUTH OF I-70. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 334 PM MDT FRI AUG 7 2015 FORECAST PROBLEM WILL BE THUNDERSTORM CHANCES AND ANY HEAVY RAINFALL THREAT. SATELLITE IS SHOWING AN AMPLIFIED AND MOSTLY PROGRESSIVE FLOW FROM THE PACIFIC INTO NORTH AMERICA. THIS FLOW BECOMES MORE OF A SPLIT WITH THE TROUGHS ALONG THE WEST AND EAST COASTS. A LOT OF PACIFIC AND MONSOONAL MOISTURE IS BEING PULLED UP INTO THE REGION. CURRENTLY A SYNOPTIC BOUNDARY REMAINS DRAPED TO OUR SOUTH AND WEST. AT JET LEVEL...MODELS STARTED OUT FINE. AT MID LEVELS...MODELS WERE NOT TOO FAR APART. THE CANADIAN/UKMET/GFS LED THE PACK WITH OTHERS NOT FAR BEHIND WITH THE SREF THE WORST. THE NAM/SREF WERE HANDLING THE SURFACE WIND AND PRESSURE FIELD THE BEST. MODELS TENDED TO BE A LITTLE COOL ON THE LOW LEVEL THERMAL FIELD WITH THE GFS/CANADIAN DOING THE BEST. SATURDAY NIGHT...TO BEGIN THE NIGHT...SURFACE BOUNDARY IS DRAPED OVER THE FAR SOUTH AND WEST CENTRAL PORTION OF THE AREA. THIS BOUNDARY GRADUALLY SINKS SOUTH THROUGH THE NIGHT. SHORTWAVE TROUGH MOVES THROUGH FROM THE SOUTHWEST THROUGH THE NIGHT WITH THE BEST LIFT BASICALLY OVER THE SOUTHWEST HALF. MAIN JET AXIS/LIFT STAYS NOT TOO FAR TO OUR NORTH AND WEST THROUGH MOST OF THE PERIOD. LATE IN THE NIGHT A RIGHT REAR QUADRANT GETS CLOSER TO THE NORTHWEST PORTION. RIGHT NOW THE HIGHEST POPS LOOK TO BE IN THE SOUTHWEST HALF. PWS REMAIN NEAR 1.5 INCHES. THAT WITH STORM MOTIONS ONLY 10 TO 15 KNOTS ALONG THAT FLOW COMING OVER THE TOP OF THE SOUTHERN BOUNDARY WILL MAKE MODERATE TO LOCALLY HEAVY RAINFALL POSSIBLE. ALSO POSSIBLE LATE IN THE NIGHT WITH MOIST LOW LEVELS AND LITTLE TO NO WIND THAT PATCHY FOG COULD DEVELOP WHERE NO PRECIPITATION IS GOING ON. SUNDAY/SUNDAY NIGHT...IT LOOKS LIKE THERE MAY BE SOME LINGERING RAINFALL AND PATCHY FOG IN THE MORNING. FOR THE REMAINDER OF THE PERIOD...BOUNDARY LOOKS TO BE TO THE SOUTH AND WEST OF THE AREA WITH A WEAK LOW LEVEL UPSLOPE REGIME IN PLACE. HOWEVER...MODELS ARE HINTING AT A WEAK SECONDARY BOUNDARY MOVING INTO THE NORTHWEST HALF OF THE AREA DURING THE LATE AFTERNOON INTO THE EVENING. THIS SINKS A LITTLE FURTHER SOUTHEAST DURING THE LAST HALF OF THE NIGHT. THE MID LEVEL FORCING THROUGH THE PERIOD REMAINS RATHER WEAK WITH THE STRONGEST IN THE EVENING. RIGHT REAR QUADRANT OF THE JET REMAINS NEAR THE NORTHERN AND WESTERN PORTIONS OF THE AREA THROUGH THE DAY BUT GETS CLOSER/HAS MORE AFFECT ON THOSE LOCATIONS BY THE END OF THE DAY. THE NORTHERN PORTION OF THE AREA KEEPS GETTING AFFECTED BY THIS THROUGH THE MIDDLE OF THE NIGHT. WITH A VARIETY OF FORCING IN DIFFERENT TIMES AND PLACES...WILL BROADBRUSH CHANCE POPS FOR THE ENTIRE NIGHT. FOR THE HIGH TEMPERATURES...WILL HAVE LOW LEVEL UPSLOPE IN PLACE THROUGH THE DAY ALONG WITH LINGERING CLOUD COVER IN THE MORNING AND DEVELOPING CLOUD COVER IN THE AFTERNOON WITH THE CONVECTION. MODEL GUIDANCE HAS TENDED TO BE A LITTLE WARM. MONDAY...JET REMAINS WELL NORTH OF THE AREA THROUGH THE DAY. MID LEVEL SHORTWAVE RIDGE IS IN PLACE THROUGH THE DAY WITH A LOT OF DRYING. A SHORTWAVE TROUGH STARTS GETTING CLOSER DURING THE END OF THE DAY. AREA IS IN A POST FRONTAL AIR MASS. DEPENDING ON WHICH MODEL YOU USE...THERE COULD BE A WEAK SUBTLE SURFACE BOUNDARY IN THE FAR SOUTH/SOUTHWEST. SO AT THIS TIME...WILL HAVE SLIGHT TO LOW CHANCE POPS IN THE FAR SOUTH AND SOUTHWEST PORTION OF THE AREA IN THE AFTERNOON. HIGH TEMPERATURES WILL BE COOLER THAN THE PREVIOUS DAY DUE TO LOWER 850 MB TEMPERATURES...UPSLOPE WINDS AND LINGERING MORNING FOG/STRATUS THAT BEGINS SUNDAY NIGHT. MONDAY NIGHT THROUGH SATURDAY...CONTINUED AMPLIFIED PATTERN REMAINS IN PLACE THROUGH THE PERIOD. HOWEVER...THE DETERMINISTIC AND ENSEMBLE OUTPUT SPREAD GETS WORSE WITH TIME...ALMOST COMPLETELY OUT OF PHASE AT TIMES. THE DIFFERENCES INVOLVE HOW THE PERSISTENT SOUTHERN UNITED STATES RIDGE AND WEST TROUGH EVOLVE WITH TIME. IN GENERAL THE ECMWF REMAINS STRONGER WITH THE RIDGE. FOR THE WESTERN TROUGH...ALL OUTPUT SUPPORTS A DEEPENING ALONG THE COAST UPPER TROUGH. DESPITE THOSE DIFFERENCES...THE CENTER OF THE RIDGE...STILL RATHER FAR SOUTH...AND THE POSITION OF THE UPPER TROUGH SHOULD CONTINUE TO ALLOW PACIFIC AND MONSOONAL MOISTURE TO PULLED UP INTO THE REGION WITH PERIODIC SHORTWAVE TROUGHS EMBEDDED WITHIN THIS FLOW. AT THE SURFACE...WPC GRAPHICS SHOW A PERSISTENT FRONTAL BOUNDARY STILL DRAPED NOT TOO FAR TO OUR SOUTH AND WEST OR OVER THE AREA. THIS KEEPS A CONTINUED UPSLOPE FLOW OVER THE AREA. GIVEN THE BIG MODEL DIFFERENCES...THE GENERAL PATTERN SUPPORTED CONTINUED BOUTS OF MOISTURE/LIFT/RAINFALL...AND THE PROXIMITY OF A BOUNDARY AND UPSLOPE FLOW...SHOULD SEE A CONTINUED THREAT FOR THUNDERSTORMS AND DO NOT FEEL COMFORTABLE MAKING ANY MAJOR ADJUSTMENTS TO THE GUIDANCE. THE DETAILS WILL HAVE TO BE REFINED AS WE GET CLOSER TO EACH EVENT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1114 PM MDT FRI AUG 7 2015 SCATTERED SHOWERS AND 6SM IN FOG WILL GIVE WAY TO 1SM OR LESS IN FOG BY 10Z SATURDAY THRU 14Z-15Z...WITH CEILINGS OVC010 OR LESS. FROM 14Z-15Z ONWARD...VFR CONDITIONS WITH SCT050-150. WINDS WILL HAVE VARYING DIRECTION THRU FORECAST PERIOD WITH 5-15KTS RANGE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JN SHORT TERM...DLF LONG TERM...BULLER AVIATION...JN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1135 PM CDT FRI AUG 7 2015 ...AVIATION UPDATE... .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 336 PM CDT FRI AUG 7 2015 ONGOING BAND OF ELEVATED SHOWERS AND THUNDERSTORMS OVER NORTH CENTRAL KANSAS CONTINUE TO BE ROOTED AROUND 10-12 THOUSAND FEET AS CEILINGS ARE NOT EVEN BEING MEASURED AT ASOS SITES. PARCELS LIFTED FROM THIS LEVEL ARE LIKELY REALIZING ON THE ORDER OF 400-800 J/KG OF CAPE AND RADAR TRENDS SUPPORT THIS AS WELL. THE BAND OF ELEVATED FORCING/CONVERGENCE/WARM ADVECTION APPEARS LIKELY TO CONTINUE FOR A WHILE ALTHOUGH INSTABILITY OF THESE ELEVATED PARCELS MAY WANE WITH TIME. BOTTOM LINE IS THAT THE SCATTERED SHOWERS AND A FEW STORMS WILL CONTINUE FOR A FEW HOURS BUT LIKELY DECREASE IN COVERAGE DURING THE EVENING. FARTHER WEST, A DEEP TROUGH OVER NEVADA WAS SPINNING AMPLE MOISTURE AND ENERGY NORTHEAST ACROSS THE CENTRAL ROCKIES AND INTO THE PLAINS. WIDESPREAD PRESSURE FALLS AND A VERY MOIST BOUNDARY LAYER OVER THE HIGH PLAINS OF COLORADO INTO NORTH TEXAS WILL LIKELY RESULT IN WIDESPREAD THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND EVENING. THESE STORMS APPEAR LIKELY TO CONGEAL INTO ONE OR MORE CONVECTIVE CLUSTERS AND MOVE TO THE EAST AND NORTHEAST. THE MOST LIKELY CLUSTER SEEMS AIMED TO MOVE ACROSS NEBRASKA TONIGHT, BUT MORE RECENT MODEL RUNS AND OBSERVATIONAL DATA SUGGEST THE POTENTIAL FOR ANOTHER WELL ORGANIZED CLUSTER TO DEVELOP IN SOUTHWEST KANSAS AND MOVE TOWARD THE NORTHEAST...LIKELY IMPACTING A GOOD PART OF THE LOCAL FORECAST AREA. WHILE THUNDERSTORMS ARE LIKELY TO DEVELOP, THEIR EVOLUTION HAS LESS CONFIDENCE AS THEY WILL INTERACT WITH THE UPPER RIDGE, DRY AIR JUST ABOVE THE BOUNDARY LAYER, AND A STOUT INVERSION/CAP JUST OFF THE SURFACE. SO, HAVE LOWER POPS WITH SOUTHERN EXTENT GIVEN THE GREATER UNCERTAINTY, BUT THE POTENTIAL DOES EXIST FOR WIDESPREAD STORMS ESPECIALLY OVER THE NORTHERN HALF OF THE FORECAST AREA TONIGHT... MAINLY AFTER MIDNIGHT. MODERATE INSTABILITY SHOULD BE AVAILABLE FOR ANY STORMS THAT DO DEVELOP, BUT THE EXTENT OF COLD POOL ORGANIZATION, ESPECIALLY GIVEN THE STRONG CAP, IS IN QUESTION. WOULD NOT BE SURPRISED TO SEE AN ORGANIZED COLD POOL SUPPORT DAMAGING WIND GUSTS INTO PART OF THE AREA...ESPECIALLY NORTH CENTRAL KANSAS...BUT IT SEEMS UNLIKELY AT THE SAME TIME. THUNDERSTORMS WILL SHIFT NORTHEAST OF THE AREA ON SATURDAY MORNING WITH A VERY MOIST BOUNDARY LAYER REMAINING IN PLACE. THE SUN WILL COME OUT IN FULL FORCE AND EXPECT A VERY HOT DAY WITH HIGHS WELL INTO THE 90S AND LOWER 100S IN SOME AREAS. WHILE SOME GUIDANCE (GFS IN PARTICULAR) MIXES VERY DEEP, IT DOES NOT APPEAR REALISTIC AND HAVE FORECAST CLOSER TO HOW PAST EVENTS HAVE BEHAVED...MAINTAINING A SHALLOW LAYER OF VERY HIGH NEAR-SURFACE DEWPOINTS AND HIGH HEAT INDICES THROUGH THE AFTERNOON. WILL NEED TO CLOSELY MONITOR THE FORECAST, ESPECIALLY FOR DEWPOINTS AND THE BEHAVIOR OF ANY REMNANT OUTFLOW, AS PARTS OF THE AREA MAY APPROACH THE 110 HEAT INDEX CRITERIA FOR AN EXCESSIVE HEAT WARNING. BY LATE IN THE AFTERNOON, EXPECT EXTREME CAPE TO DEVELOP ACROSS NORTHERN AND EASTERN KANSAS WHILE A REMNANT OUTFLOW BOUNDARY AND/OR WEAK SYNOPTIC FRONT SETS UP ACROSS PARTS OF THE LOCAL AREA AND INTO SOUTHEAST NEBRASKA. A BAND OF SEASONALLY STRONG MID LEVEL FLOW OVER THE TOP OF STRENGTHENING LOW LEVEL FLOW WILL SUPPORT LARGE LOOPING HODOGRAPHS ACROSS NORTHERN KANSAS AND ANY STORMS THAT DEVELOP APPEAR LIKELY TO DEVELOP SUPERCELL STRUCTURES. ANY STORMS IN THE LATE AFTERNOON AND EARLY EVENING WILL POSE A THREAT FOR RATHER LARGE HAIL, DAMAGING WINDS, AND A NON-ZERO TORNADO POTENTIAL. THE MAIN QUESTION IS WHERE THOSE STORMS WILL DEVELOP AND CURRENT SUGGESTIONS POINT TO AREAS NEAR AND NORTH OF THE NE/KS BORDER. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 336 PM CDT FRI AUG 7 2015 ONGOING CONVECTION MAY LINGER THROUGH THE LATE EVENING HOURS MAINLY FOR AREAS NORTH OF I-70. DURING THIS TIME FRAME A COLD FRONT POSSIBLY REINFORCED BY AN OUTFLOW BOUNDARY SHOULD EXTEND FROM FAR NORTHEAST KS TO CENTRAL KS AND GRADUALLY SLIDE SOUTHWARD OVERNIGHT. INSTABILITY BEHIND THE FRONT APPEARS TO STILL POSE THE RISK FOR ELEVATED STORMS, WHILE DEEP LAYER SHEAR IS FORECAST TO DECREASE OVERALL. THE LOW TEMPERATURES SUNDAY MORNING WILL BE QUITE WARM IN THE MID TO UPPER 70S WITH THE EXCEPTION OF FAR NORTHERN KS WHERE PRECIP MAY COOL THINGS OFF A TOUCH. AS THAT FRONT SLIDES SOUTHWARD THE MODELS ARE HINTING AT WEAK SHORTWAVES TRACKING OVER KS DURING THE DAY SUNDAY. AS FOR NOW THE COVERAGE APPEARS TO BE SCATTERED DUE TO THE WEAK LARGE SCALE FORCING. WITH POSSIBLE PRECIP AND CLOUDS AROUND THE AREA HIGH TEMPERATURES ARE SOMEWHAT UNCERTAIN. BY SUNDAY EVENING THE FRONT SHOULD REACH THE OK/KS STATE LINE. ALTHOUGH ELEVATED SHOWERS AND STORMS WILL STILL BE POSSIBLE OVERNIGHT SUNDAY ESPECIALLY SINCE THE MID/UPPER LEVEL FLOW BECOMES MORE WESTERLY OPENING THE DOOR FOR MORE WEAK SHORTWAVES TO TRACK OVER THE REGION WITH THE BETTER CHANCES SOUTH OF I-70. COOLER AIR WILL PUSH SOUTHWARD ON MONDAY GIVING US HIGHS IN THE MID TO UPPER 80S. MOST OF THE DAYTIME HOURS SHOULD BE DRY ON MONDAY ALTHOUGH A SHORTWAVE WILL DIG ACROSS THE UPPER MIDWEST LATE MONDAY BRINGING A SECONDARY BOUNDARY SOUTHWARD THROUGH NE. STORMS DEVELOPING ON THIS BOUNDARY COULD GET CLOSE TO FAR NORTHERN KS. MID WEEK TIME FRAME LOOKS TO BE QUIET WEATHER WISE AT THIS POINT. BOTH GFS AND ECMWF ARE IN GOOD AGREEMENT EARLY IN THE PERIOD WITH A LARGE SCALE TROUGH OVER THE WEST AND EAST COAST OF THE CONUS. IN THE MIDDLE GROUND IS A HIGHLY AMPLIFIED RIDGE OVER THE CENTRAL CONUS. THE DIFFERENCE COMES LATER IN THE PERIOD WHERE THE GFS DOES SUGGEST THAT THE RIDGE AXIS WILL BECOME MORE NARROW OVER THE CENTRAL CONUS BY LATE WEDNESDAY AS A CUT-OFF LOW MAY SET UP ALONG THE CENTRAL CALIFORNIA COAST. THE MAIN WESTERLIES ARE FORCED AROUND THE NORTHERN PERIPHERY OF THIS UPPER LOW WHICH COULD ALLOW FOR A TROUGH TO DIG INTO THE NORTHERN ROCKIES WITH AN ASSOCIATED DEEPENING LOW MOVING ALONG THE US/CANADIAN BORDER. WITHIN A LEESIDE TROUGH SETTING UP AND THIS MID TO UPPER LEVEL TROUGH FEATURE TO THE NORTH, A SURFACE WARM FRONT COULD EXTEND INTO THE CENTRAL PLAINS AND CAUSE SOME SMALL CHANCES FOR PRECIP BY AROUND FRIDAY MORNING TIME FRAME. THIS CHANCE LOOKS TO BE MINIMAL AT THIS POINT, SO OPTED TO KEEP SLIGHT POP CHANCES IN THE FORECAST AT THIS TIME. TEMPS ARE EXPECTED TO BE IN CHECK DURING THE UPCOMING WEEK WITH A CANADIAN HIGH PRESSURE RIDGE INFLUENCING THE REGION, SO HIGHS SHOULD REMAIN IN THE UPPER 80S WITH LOWS IN THE MID TO UPPER 60S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1135 PM CDT FRI AUG 7 2015 THERE IS QUITE A BIT OF UNCERTAINTY IN WHERE THE MCS WILL GO DURING THE EARLY MORNING HOURS. THE HRRR HAS BEEN CONSISTENTLY BRINGING THE ELEVATED STORMS THROUGH EASTERN KS, ALTHOUGH IT SEEMS TO BE DELAYING THE PROGRESS TO MORE MID MORNING. MEANWHILE THE OPERATIONAL MODELS CONTINUE TO FOCUS THE MOST LIKELY TRACK OF THE STORMS ACROSS SOUTHERN NEB AND FAR NORTHERN KS. WITH PROFILER DATA SHOWING THE DECENT LOW LEVEL JET VEERING TO THE SOUTH AND SOUTHWEST, THINK THERE IS A CHANCE FOR ELEVATED STORMS TO MOVE INTO THE TERMINALS SO WILL INCLUDE A VCTS WITH VFR CONDITIONS AND MONITOR TRENDS. && .TOP WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM NOON TO 9 PM CDT SATURDAY FOR KSZ010>012- 021>024-026-034>040-054>056-058-059. && $$ SHORT TERM...BARJENBRUCH LONG TERM...DRAKE/SANDERS AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1018 PM MDT FRI AUG 7 2015 .UPDATE... ISSUED AT 1018 PM MDT FRI AUG 7 2015 UPDATE SENT TO CANCEL SEVERE THUNDERSTORM WATCH FOR THE ENTIRE AREA. SEVERE THREAT HAS SHIFTED EAST OF THE CWA...BUT DO EXPECT SCATTERED RW/TRW TO PERSIST BUT TAPER AS THE OVERNIGHT HRS PROGRESS. FLASH FLOOD WARNING REMAINS IN EFFECT FOR HITCHCOCK COUNTY IN NEBRASKA. CONCERN IS FOR HEAVY RAINFALL THAT OCCURRED JUST TO THE NORTH EARLIER THIS EVENING IN CHASE/HAYS COUNTIES... WILL FILTER SOUTH VIA THE FRENCHMEN CREEK AND AFFECT AREAS LIKE STRATTON...CULBERTSON. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 159 PM MDT FRI AUG 7 2015 BIGGEST CHALLENGE IN SHORT TERM IS THUNDERSTORM POTENTIAL THIS AFTERNOON AND OVERNIGHT. NUMEROUS RUNS OF THE RAP PERSIST IN BREAKING OUT SCATTERED AFTERNOON CONVECTION ACROSS THE CENTRAL AND NORTHEAST COUNTIES...GENERALLY IN THE VICINITY OF A VERY WEAK DECAYING SURFACE BOUNDARY. HAVE SOME DOUBTS ABOUT THIS LOOKING AT CURRENT SATELLITE TRENDS AND SPC MESOANALYSIS CINH...BUT HAVE LEFT THE SLIGHT CHANCE POPS NONETHELESS. BIGGER ISSUE IS DEVELOPMENT OF STORMS OVER COLORADO LATER THIS AFTERNOON AND THEIR SUBSEQUENT MOVEMENT. WATER VAPOR IMAGERY SHOWS THE APPROACH OF THE NEXT UPSTREAM SHORTWAVE TROUGH AND RADAR NOW SHOWS INITIAL THUNDERSTORM DEVELOPMENT SOUTH OF DENVER. MOST GUIDANCE...INCLUDING THE CONVECTION-ALLOWING MODELS...INDICATES BEST COVERAGE OF STORMS WILL BE ACROSS NORTHEAST COLORADO INTO SOUTHWEST NEBRASKA...CLIPPING NORTHWEST KANSAS WITH LESSER COVERAGE SOUTH AND EAST. ULTIMATELY IT DEPENDS ON UPSCALE DEVELOPMENT AND WHETHER OR NOT A DECENT MCS CAN DEVELOP AND PRODUCE STORMS FURTHER SOUTHEAST OF THE MAIN SHORTWAVE. HAVE CONTINUED THE PREVIOUS FORECAST TREND OF BEST COVERAGE NORTH AND NORTHWEST WITH LESSER POTENTIAL SOUTH OF I-70. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 334 PM MDT FRI AUG 7 2015 FORECAST PROBLEM WILL BE THUNDERSTORM CHANCES AND ANY HEAVY RAINFALL THREAT. SATELLITE IS SHOWING AN AMPLIFIED AND MOSTLY PROGRESSIVE FLOW FROM THE PACIFIC INTO NORTH AMERICA. THIS FLOW BECOMES MORE OF A SPLIT WITH THE TROUGHS ALONG THE WEST AND EAST COASTS. A LOT OF PACIFIC AND MONSOONAL MOISTURE IS BEING PULLED UP INTO THE REGION. CURRENTLY A SYNOPTIC BOUNDARY REMAINS DRAPED TO OUR SOUTH AND WEST. AT JET LEVEL...MODELS STARTED OUT FINE. AT MID LEVELS...MODELS WERE NOT TOO FAR APART. THE CANADIAN/UKMET/GFS LED THE PACK WITH OTHERS NOT FAR BEHIND WITH THE SREF THE WORST. THE NAM/SREF WERE HANDLING THE SURFACE WIND AND PRESSURE FIELD THE BEST. MODELS TENDED TO BE A LITTLE COOL ON THE LOW LEVEL THERMAL FIELD WITH THE GFS/CANADIAN DOING THE BEST. SATURDAY NIGHT...TO BEGIN THE NIGHT...SURFACE BOUNDARY IS DRAPED OVER THE FAR SOUTH AND WEST CENTRAL PORTION OF THE AREA. THIS BOUNDARY GRADUALLY SINKS SOUTH THROUGH THE NIGHT. SHORTWAVE TROUGH MOVES THROUGH FROM THE SOUTHWEST THROUGH THE NIGHT WITH THE BEST LIFT BASICALLY OVER THE SOUTHWEST HALF. MAIN JET AXIS/LIFT STAYS NOT TOO FAR TO OUR NORTH AND WEST THROUGH MOST OF THE PERIOD. LATE IN THE NIGHT A RIGHT REAR QUADRANT GETS CLOSER TO THE NORTHWEST PORTION. RIGHT NOW THE HIGHEST POPS LOOK TO BE IN THE SOUTHWEST HALF. PWS REMAIN NEAR 1.5 INCHES. THAT WITH STORM MOTIONS ONLY 10 TO 15 KNOTS ALONG THAT FLOW COMING OVER THE TOP OF THE SOUTHERN BOUNDARY WILL MAKE MODERATE TO LOCALLY HEAVY RAINFALL POSSIBLE. ALSO POSSIBLE LATE IN THE NIGHT WITH MOIST LOW LEVELS AND LITTLE TO NO WIND THAT PATCHY FOG COULD DEVELOP WHERE NO PRECIPITATION IS GOING ON. SUNDAY/SUNDAY NIGHT...IT LOOKS LIKE THERE MAY BE SOME LINGERING RAINFALL AND PATCHY FOG IN THE MORNING. FOR THE REMAINDER OF THE PERIOD...BOUNDARY LOOKS TO BE TO THE SOUTH AND WEST OF THE AREA WITH A WEAK LOW LEVEL UPSLOPE REGIME IN PLACE. HOWEVER...MODELS ARE HINTING AT A WEAK SECONDARY BOUNDARY MOVING INTO THE NORTHWEST HALF OF THE AREA DURING THE LATE AFTERNOON INTO THE EVENING. THIS SINKS A LITTLE FURTHER SOUTHEAST DURING THE LAST HALF OF THE NIGHT. THE MID LEVEL FORCING THROUGH THE PERIOD REMAINS RATHER WEAK WITH THE STRONGEST IN THE EVENING. RIGHT REAR QUADRANT OF THE JET REMAINS NEAR THE NORTHERN AND WESTERN PORTIONS OF THE AREA THROUGH THE DAY BUT GETS CLOSER/HAS MORE AFFECT ON THOSE LOCATIONS BY THE END OF THE DAY. THE NORTHERN PORTION OF THE AREA KEEPS GETTING AFFECTED BY THIS THROUGH THE MIDDLE OF THE NIGHT. WITH A VARIETY OF FORCING IN DIFFERENT TIMES AND PLACES...WILL BROADBRUSH CHANCE POPS FOR THE ENTIRE NIGHT. FOR THE HIGH TEMPERATURES...WILL HAVE LOW LEVEL UPSLOPE IN PLACE THROUGH THE DAY ALONG WITH LINGERING CLOUD COVER IN THE MORNING AND DEVELOPING CLOUD COVER IN THE AFTERNOON WITH THE CONVECTION. MODEL GUIDANCE HAS TENDED TO BE A LITTLE WARM. MONDAY...JET REMAINS WELL NORTH OF THE AREA THROUGH THE DAY. MID LEVEL SHORTWAVE RIDGE IS IN PLACE THROUGH THE DAY WITH A LOT OF DRYING. A SHORTWAVE TROUGH STARTS GETTING CLOSER DURING THE END OF THE DAY. AREA IS IN A POST FRONTAL AIR MASS. DEPENDING ON WHICH MODEL YOU USE...THERE COULD BE A WEAK SUBTLE SURFACE BOUNDARY IN THE FAR SOUTH/SOUTHWEST. SO AT THIS TIME...WILL HAVE SLIGHT TO LOW CHANCE POPS IN THE FAR SOUTH AND SOUTHWEST PORTION OF THE AREA IN THE AFTERNOON. HIGH TEMPERATURES WILL BE COOLER THAN THE PREVIOUS DAY DUE TO LOWER 850 MB TEMPERATURES...UPSLOPE WINDS AND LINGERING MORNING FOG/STRATUS THAT BEGINS SUNDAY NIGHT. MONDAY NIGHT THROUGH SATURDAY...CONTINUED AMPLIFIED PATTERN REMAINS IN PLACE THROUGH THE PERIOD. HOWEVER...THE DETERMINISTIC AND ENSEMBLE OUTPUT SPREAD GETS WORSE WITH TIME...ALMOST COMPLETELY OUT OF PHASE AT TIMES. THE DIFFERENCES INVOLVE HOW THE PERSISTENT SOUTHERN UNITED STATES RIDGE AND WEST TROUGH EVOLVE WITH TIME. IN GENERAL THE ECMWF REMAINS STRONGER WITH THE RIDGE. FOR THE WESTERN TROUGH...ALL OUTPUT SUPPORTS A DEEPENING ALONG THE COAST UPPER TROUGH. DESPITE THOSE DIFFERENCES...THE CENTER OF THE RIDGE...STILL RATHER FAR SOUTH...AND THE POSITION OF THE UPPER TROUGH SHOULD CONTINUE TO ALLOW PACIFIC AND MONSOONAL MOISTURE TO PULLED UP INTO THE REGION WITH PERIODIC SHORTWAVE TROUGHS EMBEDDED WITHIN THIS FLOW. AT THE SURFACE...WPC GRAPHICS SHOW A PERSISTENT FRONTAL BOUNDARY STILL DRAPED NOT TOO FAR TO OUR SOUTH AND WEST OR OVER THE AREA. THIS KEEPS A CONTINUED UPSLOPE FLOW OVER THE AREA. GIVEN THE BIG MODEL DIFFERENCES...THE GENERAL PATTERN SUPPORTED CONTINUED BOUTS OF MOISTURE/LIFT/RAINFALL...AND THE PROXIMITY OF A BOUNDARY AND UPSLOPE FLOW...SHOULD SEE A CONTINUED THREAT FOR THUNDERSTORMS AND DO NOT FEEL COMFORTABLE MAKING ANY MAJOR ADJUSTMENTS TO THE GUIDANCE. THE DETAILS WILL HAVE TO BE REFINED AS WE GET CLOSER TO EACH EVENT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 546 PM MDT FRI AUG 7 2015 BOTH SITES WILL SEE VFR CONDITIONS GIVE WAY TO THUNDERSTORM DEVELOPMENT FROM 02Z-06Z. AFT 06Z...FOG BEGINS TO DEVELOP AS WINDS SLACKEN BY 06Z WITH 6SM DROPPING DOWN TO 1SM OR LESS WITH CEILINGS BLW OVC010 BY 09Z...LASTING THRU 15Z ESPECIALLY FOR KMCK. AFT THAT...VFR WITH SCATTERED CLOUD COVER. WINDS SE 15-25KTS...BECM LGT/VAR BY 06Z THEN NNE AROUND 10KTS 14Z-15Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JN SHORT TERM...DLF LONG TERM...BULLER AVIATION...JN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1057 PM EDT SUN AUG 9 2015 .UPDATE... ISSUED AT 1045 PM EDT SUN AUG 9 2015 A SHORTWAVE MOVING THROUGH THE OH VALLEY REGION IS BRINGING SOME SHOWERS TO SOUTHERN OH AND NORTHERN KY. KCVG ONLY TRACED AS THESE PASSED...SO THESE LIKELY DO NOT AMOUNT TO MUCH MORE THAN SPRINKLES. OTHERWISE...MODELS INDICATE ADDITIONAL CONVECTION UPSTREAM WILL MOVE EAST AND OR DEVELOP AND MOVE EAST TO EAST SOUTHEAST AS IT WORKS AROUND THE MID LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS. DUE TO UNCERTAINTY IN TIMING AND MODEL DIFFERENCES IN EVOLUTION OF CONVECTION OVERNIGHT AND INTO THE DAY ON MONDAY...NO CHANGES WERE MADE TO POPS TOWARD DAWN. THE ONLY CHANGES TO POPS WERE IN THE SHORT TERM TO ACCOUNT FOR THE SHOWERS MOVING TOWARD NE KY. OTHERWISE...HOURLY GRIDS WERE FRESHENED UP BASED ON RECENT OBSERVATIONS AND SATELLITE TRENDS. UPDATE ISSUED AT 820 PM EDT SUN AUG 9 2015 A MID LEVEL RIDGE OF HIGH PRESSURE WAS CENTERED OVER THE SOUTHERN PLAINS WITH A SERIES OF SHORTWAVES MOVING THROUGH OR NEARING THE LOWER OH VALLEY AS THEY MOVE AROUND THIS RIDGE. AT THE SAME TIME... A SERIES OF SHORTWAVE TROUGH WILL APPROACH OR MOVE THROUGH THE GREAT LAKES. ALL OF THIS WILL BEGIN TO CARVE OUT AN EASTERN US TROUGH WHILE THE RIDGE BUILDS NORTH INTO THE NORTHERN ROCKIES. AT THE SFC..AN AREA OF LOW PRESSURE WILL TRACK INTO THE LOWER GREAT LAKES WITH THE WARM FRONT LIFTING INTO THE REGION WHILE A COLD FRONT MOVES INTO THE LOWER OH VALLEY. OVERALL...MOISTURE AND FORCING WILL INCREASE OVERNIGHT ACROSS THE OH VALLEY REGION...BUT CONFIDENCE REMAINS LOW IN THE EVOLUTION OF CONVECTION OVERNIGHT. WITH RECENT MODEL GUIDANCE STILL SUPPORTING CHANCES FOR CONVECTION LATE TONIGHT AND SOME DISAGREEMENT AS TO WHERE CHANCES MAY BE BEST...NO CHANGES WERE MADE TO POPS AND WEATHER ATTM. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 345 PM EDT SUN AUG 9 2015 18Z SFC ANALYSIS SHOWS HIGH PRESSURE STILL IN CONTROL OF THE WEATHER ACROSS EAST KENTUCKY. HIGH CLOUDS ARE MOVING IN FROM THE NORTHWEST AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM WHILE SCATTERED CU IS DISSIPATING OVER THE AREA. TEMPERATURES ARE TOPPING OUT IN THE MIDDLE TO UPPER 80S THROUGH EAST KENTUCKY WHILE DEWPOINTS VARY FROM THE MID 60S NORTH TO THE LOWER 70S IN THE SOUTH WITH LIGHT AND VARIABLE WINDS. THE MODELS ARE IN GOOD AGREEMENT WITH THE PATTERN ALOFT OVER THE REGION. THEY ALL DEPICT KENTUCKY ON THE NORTHEAST FRINGE OF A STRONG RIDGE CENTERED OVER CENTRAL TEXAS. THIS PLACES THE AREA IN NORTHWEST FLOW WITH A COUPLE OF MINOR SHORTWAVES GLIDING PAST THE CWA INTO MONDAY MORNING. THE PATTERN WILL FURTHER AMPLIFY THROUGH THE OHIO VALLEY AND APPALACHIANS AS A TROUGH FROM CENTRAL CANADA WILL DIVE INTO THE GREAT LAKES LATER MONDAY...SWEEPING INTO THE OHIO VALLEY BY 12Z TUESDAY. SIGNIFICANT HEIGHT FALLS WILL SPREAD OVER EASTERN KENTUCKY AS A RESPONSE ALONG WITH ADDITIONAL ENERGY CLUSTERS. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED THE HIGHER RESOLUTION HRRR AND NAM12 MOST CLOSELY INITIALLY FOLLOWING WITH WITH IDEAS FROM THE GFS AND ECMWF LATER ON IN THE SHORT TERM. SENSIBLE WEATHER WILL FEATURE A QUIET EVENING UNDER HIGH CLOUDS...THIN ENOUGH TO YIELD A SMALL RIDGE TO VALLEY TEMPERATURE SPLIT. THE CLOUDS WILL THICKEN UP DURING THE EARLY MORNING HOURS WITH A SEMI-ORGANIZED AREA OF SHOWERS AND THUNDERSTORMS POTENTIALLY MOVING INTO THE AREA DURING THE PRE-DAWN HOURS FROM NORTHWEST TO SOUTHEAST. THIS MAY STABILIZE THE ENVIRONMENT FOR A TIME BEFORE INSTABILITY BUILDS ENOUGH FOR ANOTHER ROUND OF ACTIVITY LATER IN THE DAY MONDAY. FROM EITHER OF THESE ROUNDS OF CONVECTION A STORM OR TWO COULD GET STRONG ENOUGH TO MAKE DAMAGING WIND GUSTS A POTENTIAL THREAT - WILL ADDRESS THIS IN THE FORTHCOMING HWO. THIS SYSTEM/S COLD FRONT WILL PASS THROUGH LATER MONDAY NIGHT WITH A LINGER SHOT AT SHOWERS OR STORMS AS IT EXITS EARLY TUESDAY MORNING. DUE TO THE CLOUD COVER TONIGHT AND MONDAY NIGHT HAVE KEPT FOG TO A MINIMUM IN THE GRIDS...BUT IT COULD BE MORE SUBSTANTIAL TUESDAY MORNING SHOULD THE CLOUDS AND PCPN MANAGE TO CLEAR OUT EARLIER MONDAY NIGHT. AGAIN USED THE SHORTBLEND GUIDANCE AS A STARTING POINT THROUGH THE FIRST PART OF THE FORECAST FOR THE T/TD/WIND GRIDS WITH A SWITCH TO THE SUPERBLEND FOR THE REMAINDER. DID MAKE SOME MINOR CHANGES TO LOWS TONIGHT BASED ON THE TERRAIN WITH A SMALL RIDGE TO VALLEY SPLIT EXPECTED INTO THE EARLY MORNING HOURS. AS FOR POPS...ENDED UP CLOSEST TO THE MET NUMBERS THROUGH THE PERIOD. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 313 PM EDT SUN AUG 9 2015 THE MAJORITY OF THE EXTENDED LOOKS TO BE DRY AND PLEASANT WITH SHOWERS AND STORMS AFFECTING EASTERN KENTUCKY DURING THE DAY ON TUESDAY...AND BELOW NORMAL TEMPERATURES TUESDAY THROUGH FRIDAY. MOIST UPSLOPE FLOW BEHIND A DEPARTING WEATHER SYSTEM WILL ALLOW PRECIPITATION TO LINGER ACROSS THE AREA THROUGH LATE TUESDAY AFTERNOON. THE PRECIPITATION WILL BE USHERED OUT OF EASTERN KENTUCKY AS A STRONG RIDGE OF HIGH PRESSURE BEGINS BUILDING INTO THE AREA FROM THE WEST. THIS FEATURE WILL BRING DRY CONDITIONS AND COOLER THAN NORMAL TEMPERATURES TO EAST KENTUCKY FOR THE REST OF THE WEEK...AS A COOL AND DRY AIR MASS MOVES FROM THE NORTHERN ROCKY MOUNTAIN REGION AND INTO THE OHIO AND TENNESSEE VALLEY REGIONS. HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY ARE EXPECTED TO MAX OUT IN THE UPPER 70S FOR MOST LOCATIONS...WITH LOWER 80S FOR HIGHS ON TAP FOR TUESDAY AND FRIDAY. OVERNIGHT LOWS MAY FALL AS LOW AS THE MID TO UPPER 50S WEDNESDAY NIGHT AND THURSDAY NIGHT AS CLEAR SKIES AND NEAR CALM WINDS REMAIN IN PLACE. MINIMUM READINGS ARE EXPECTED TO BOTTOM OUT IN THE 60S THE OTHER NIGHTS OF THE UPCOMING WORK WEEK...WITH LOW TO MID 60S EXPECTED FOR FRIDAY NIGHT AND SATURDAY NIGHT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 825 PM EDT SUN AUG 9 2015 VFR IS CURRENTLY OBSERVED ACROSS THE AREA AND VFR SHOULD PERSIST THROUGH AT LEAST 6Z. HOWEVER...WITH INCREASING MID AND HIGH LEVEL MOISTURE...MID AND HIGH CLOUDS WILL ALSO INCREASE AND SHOULD KEEP FOG AT BAY AT LEAST FOR THE TAF SITES. A SERIES OF SHORTWAVE TROUGHS AND AN APPROACHING COLD FRONT WILL BRING A THREAT FOR A SEMI- ORGANIZED CLUSTER OF SHOWERS AND STORMS TO MOVE INTO CWA PARTICULARLY THE NORTH AROUND 9Z...AND THEN TRANSLATE SOUTH AND EAST. A TEMPO GROUP WITH CIGS AND VIS INTO THE IFR TO MVFR RANGE WITH THE CONVECTION WAS CONTINUED TO BE USED AT SYM...JKL AND SJS. ADDITIONAL STORMS WILL BE POSSIBLE THROUGH THE REST OF THE DAY...PARTICULARLY AFTER 16Z TO 18Z...WHEN ANOTHER TEMPO GROUP WAS USED. OUTSIDE OF THESE TIMES PREVAILING VFR WITH VCTS WAS USED. THUNDERSTORM WIND GUSTS COULD REACH 25 KT OR HIGHER...ALTHOUGH OUTSIDE OF STORMS WINDS SHOULD AVERAGE 10 KT OR LESS THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...AR AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
833 PM EDT SUN AUG 9 2015 .UPDATE... ISSUED AT 820 PM EDT SUN AUG 9 2015 A MID LEVEL RIDGE OF HIGH PRESSURE WAS CENTERED OVER THE SOUTHERN PLAINS WITH A SERIES OF SHORTWAVES MOVING THROUGH OR NEARING THE LOWER OH VALLEY AS THEY MOVE AROUND THIS RIDGE. AT THE SAME TIME... A SERIES OF SHORTWAVE TROUGH WILL APPROACH OR MOVE THROUGH THE GREAT LAKES. ALL OF THIS WILL BEGIN TO CARVE OUT AN EASTERN US TROUGH WHILE THE RIDGE BUILDS NORTH INTO THE NORTHERN ROCKIES. AT THE SFC..AN AREA OF LOW PRESSURE WILL TRACK INTO THE LOWER GREAT LAKES WITH THE WARM FRONT LIFTING INTO THE REGION WHILE A COLD FRONT MOVES INTO THE LOWER OH VALLEY. OVERALL...MOISTURE AND FORCING WILL INCREASE OVERNIGHT ACROSS THE OH VALLEY REGION...BUT CONFIDENCE REMAINS LOW IN THE EVOLUTION OF CONVECTION OVERNIGHT. WITH RECENT MODEL GUIDANCE STILL SUPPORTING CHANCES FOR CONVECTION LATE TONIGHT AND SOME DISAGREEMENT AS TO WHERE CHANCES MAY BE BEST...NO CHANGES WERE MADE TO POPS AND WEATHER ATTM. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 345 PM EDT SUN AUG 9 2015 18Z SFC ANALYSIS SHOWS HIGH PRESSURE STILL IN CONTROL OF THE WEATHER ACROSS EAST KENTUCKY. HIGH CLOUDS ARE MOVING IN FROM THE NORTHWEST AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM WHILE SCATTERED CU IS DISSIPATING OVER THE AREA. TEMPERATURES ARE TOPPING OUT IN THE MIDDLE TO UPPER 80S THROUGH EAST KENTUCKY WHILE DEWPOINTS VARY FROM THE MID 60S NORTH TO THE LOWER 70S IN THE SOUTH WITH LIGHT AND VARIABLE WINDS. THE MODELS ARE IN GOOD AGREEMENT WITH THE PATTERN ALOFT OVER THE REGION. THEY ALL DEPICT KENTUCKY ON THE NORTHEAST FRINGE OF A STRONG RIDGE CENTERED OVER CENTRAL TEXAS. THIS PLACES THE AREA IN NORTHWEST FLOW WITH A COUPLE OF MINOR SHORTWAVES GLIDING PAST THE CWA INTO MONDAY MORNING. THE PATTERN WILL FURTHER AMPLIFY THROUGH THE OHIO VALLEY AND APPALACHIANS AS A TROUGH FROM CENTRAL CANADA WILL DIVE INTO THE GREAT LAKES LATER MONDAY...SWEEPING INTO THE OHIO VALLEY BY 12Z TUESDAY. SIGNIFICANT HEIGHT FALLS WILL SPREAD OVER EASTERN KENTUCKY AS A RESPONSE ALONG WITH ADDITIONAL ENERGY CLUSTERS. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED THE HIGHER RESOLUTION HRRR AND NAM12 MOST CLOSELY INITIALLY FOLLOWING WITH WITH IDEAS FROM THE GFS AND ECMWF LATER ON IN THE SHORT TERM. SENSIBLE WEATHER WILL FEATURE A QUIET EVENING UNDER HIGH CLOUDS...THIN ENOUGH TO YIELD A SMALL RIDGE TO VALLEY TEMPERATURE SPLIT. THE CLOUDS WILL THICKEN UP DURING THE EARLY MORNING HOURS WITH A SEMI-ORGANIZED AREA OF SHOWERS AND THUNDERSTORMS POTENTIALLY MOVING INTO THE AREA DURING THE PRE-DAWN HOURS FROM NORTHWEST TO SOUTHEAST. THIS MAY STABILIZE THE ENVIRONMENT FOR A TIME BEFORE INSTABILITY BUILDS ENOUGH FOR ANOTHER ROUND OF ACTIVITY LATER IN THE DAY MONDAY. FROM EITHER OF THESE ROUNDS OF CONVECTION A STORM OR TWO COULD GET STRONG ENOUGH TO MAKE DAMAGING WIND GUSTS A POTENTIAL THREAT - WILL ADDRESS THIS IN THE FORTHCOMING HWO. THIS SYSTEM/S COLD FRONT WILL PASS THROUGH LATER MONDAY NIGHT WITH A LINGER SHOT AT SHOWERS OR STORMS AS IT EXITS EARLY TUESDAY MORNING. DUE TO THE CLOUD COVER TONIGHT AND MONDAY NIGHT HAVE KEPT FOG TO A MINIMUM IN THE GRIDS...BUT IT COULD BE MORE SUBSTANTIAL TUESDAY MORNING SHOULD THE CLOUDS AND PCPN MANAGE TO CLEAR OUT EARLIER MONDAY NIGHT. AGAIN USED THE SHORTBLEND GUIDANCE AS A STARTING POINT THROUGH THE FIRST PART OF THE FORECAST FOR THE T/TD/WIND GRIDS WITH A SWITCH TO THE SUPERBLEND FOR THE REMAINDER. DID MAKE SOME MINOR CHANGES TO LOWS TONIGHT BASED ON THE TERRAIN WITH A SMALL RIDGE TO VALLEY SPLIT EXPECTED INTO THE EARLY MORNING HOURS. AS FOR POPS...ENDED UP CLOSEST TO THE MET NUMBERS THROUGH THE PERIOD. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 313 PM EDT SUN AUG 9 2015 THE MAJORITY OF THE EXTENDED LOOKS TO BE DRY AND PLEASANT WITH SHOWERS AND STORMS AFFECTING EASTERN KENTUCKY DURING THE DAY ON TUESDAY...AND BELOW NORMAL TEMPERATURES TUESDAY THROUGH FRIDAY. MOIST UPSLOPE FLOW BEHIND A DEPARTING WEATHER SYSTEM WILL ALLOW PRECIPITATION TO LINGER ACROSS THE AREA THROUGH LATE TUESDAY AFTERNOON. THE PRECIPITATION WILL BE USHERED OUT OF EASTERN KENTUCKY AS A STRONG RIDGE OF HIGH PRESSURE BEGINS BUILDING INTO THE AREA FROM THE WEST. THIS FEATURE WILL BRING DRY CONDITIONS AND COOLER THAN NORMAL TEMPERATURES TO EAST KENTUCKY FOR THE REST OF THE WEEK...AS A COOL AND DRY AIR MASS MOVES FROM THE NORTHERN ROCKY MOUNTAIN REGION AND INTO THE OHIO AND TENNESSEE VALLEY REGIONS. HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY ARE EXPECTED TO MAX OUT IN THE UPPER 70S FOR MOST LOCATIONS...WITH LOWER 80S FOR HIGHS ON TAP FOR TUESDAY AND FRIDAY. OVERNIGHT LOWS MAY FALL AS LOW AS THE MID TO UPPER 50S WEDNESDAY NIGHT AND THURSDAY NIGHT AS CLEAR SKIES AND NEAR CALM WINDS REMAIN IN PLACE. MINIMUM READINGS ARE EXPECTED TO BOTTOM OUT IN THE 60S THE OTHER NIGHTS OF THE UPCOMING WORK WEEK...WITH LOW TO MID 60S EXPECTED FOR FRIDAY NIGHT AND SATURDAY NIGHT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 825 PM EDT SUN AUG 9 2015 VFR IS CURRENTLY OBSERVED ACROSS THE AREA AND VFR SHOULD PERSIST THROUGH AT LEAST 6Z. HOWEVER...WITH INCREASING MID AND HIGH LEVEL MOISTURE...MID AND HIGH CLOUDS WILL ALSO INCREASE AND SHOULD KEEP FOG AT BAY AT LEAST FOR THE TAF SITES. A SERIES OF SHORTWAVE TROUGHS AND AN APPROACHING COLD FRONT WILL BRING A THREAT FOR A SEMI- ORGANIZED CLUSTER OF SHOWERS AND STORMS TO MOVE INTO CWA PARTICULARLY THE NORTH AROUND 9Z...AND THEN TRANSLATE SOUTH AND EAST. A TEMPO GROUP WITH CIGS AND VIS INTO THE IFR TO MVFR RANGE WITH THE CONVECTION WAS CONTINUED TO BE USED AT SYM...JKL AND SJS. ADDITIONAL STORMS WILL BE POSSIBLE THROUGH THE REST OF THE DAY...PARTICULARLY AFTER 16Z TO 18Z...WHEN ANOTHER TEMPO GROUP WAS USED. OUTSIDE OF THESE TIMES PREVAILING VFR WITH VCTS WAS USED. THUNDERSTORM WIND GUSTS COULD REACH 25 KT OR HIGHER...ALTHOUGH OUTSIDE OF STORMS WINDS SHOULD AVERAGE 10 KT OR LESS THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...AR AVIATION...JP
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1052 PM EDT SUN AUG 9 2015 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 326 PM EDT SUN AUG 9 2015 SHOWERS AND THUNDERSTORMS CHANCES WILL INCREASE TONIGHT INTO MONDAY. MANY AREAS SHOULD SEE AROUND A HALF INCH OF RAIN IN THIS PERIOD... HOWEVER SEVERE WEATHER IS GENERALLY NOT EXPECTED. A FEW SHOWERS MAY LINGER INTO MONDAY EVENING...BUT WE SHOULD GRADUALLY DRY OUT... MAKING FOR A PLEASANT TUESDAY WITH LESS HUMIDITY. MUCH OF THE REMAINDER OF THE WEEK LOOKS DRY WITH NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES...WITH DAYTIME HIGHS GENERALLY 80 TO 85. A WIDELY SCATTERED THUNDERSTORM WILL BE POSSIBLE ON THURSDAY. && .UPDATE... ISSUED AT 1050 PM EDT SUN AUG 9 2015 I HAVE UPDATED THE FORECAST TO INCREASE THE RISK FOR THUNDERSTORMS TOWARD MORNING OVER OUR SOUTHWEST CWA THEN SPREAD THAT CONVECTION EASTWARD. WE ALREADY HAD LIKELY POP FOR MONDAY MORNING AFTER 8 AM...SO THIS JUST STARTS THE CONVECTION A TOUCH SOONER. WHAT I AM SEEING FROM BOTH THE WATER VAPOR IMAGE LOOPS AND WATCHING THE RAP MODEL HOURLY IS THAT WE HAVE A JET EXIT REGION WITH DECENT PVU (POTENTIAL VORTICITY) IN THE 500 TO 300 MB LAYER COMING THROUGH THE I-94 TO I-96 AREA BETWEEN 4 AM AND 9 AM THIS MORNING. A WEAK LLJ DEVELOPS IN RESPONSE TO THIS AIMED AT AZO BTW 8 AM AND 10 AM. SINCE THE HRRR...HRRR EXPERIMENTAL...AND RAP13 HAVE BEEN RATHER CONSISTENT WITH THIS AND IT MAKES SENSE GIVEN WHAT IS GOING ON NOW... I AM DID UPDATE THE GRIDS TO REFLECT THE IDEA OF THUNDERSTORMS TOWARD MORNING. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 326 PM EDT SUN AUG 9 2015 RAIN CHANCES OVER SW MI WILL PEAK DURING THE FIRST HALF OF MONDAY AS A COLD FRONT APPROACHES. GIVEN THE FRONT/S TIMING SEVERE WEATHER IS GENERALLY NOT EXPECTED. WE DRY OUT MONDAY EVENING...BECOMING COOLER AND LESS HUMID INTO TUESDAY. A COLD FRONT WAS MOVING ACROSS THE MN/WI BORDER THIS AFTERNOON AND HAS AN AREA OF SHOWERS AND STORMS WITH IT. THE STRONGEST AREA OF STORMS WAS ASSOCIATED WITH THE LEFT EXIT REGION OF THE UPPER JET. THE FRONT AND THE UPPER JET WILL MAKE IT/S WAY THROUGH THE CWA MONDAY MORNING INTO EARLY AFTERNOON...NORMALLY A MIN TIME FOR SEVERE WX. THIS LIKELY FAVORS AREAS TO OUR EAST FOR THE POTENTIAL OF STRONGER STORMS. THE OTHER PARAMETER GOING AGAINST SEVERE STORMS IS THAT THE 0-6 KM BULK SHEAR IS ONLY 20-25 KNOTS OVER SW MI AS THE FRONT COMES THROUGH. HOWEVER THE FRONT WILL BE HEADING INTO A JUICY AIR MASS WITH DEW POINTS AROUND 70 ALONG I-94...AND MID TO UPPER 60S ELSEWHERE ACROSS THE CWA. SO EXPECT THE STORMS OVER MN/WI TO HOLD TOGETHER AND EXPAND...BRINGING A BENEFICIAL RAIN TO MOST OF THE CWA LATE TONIGHT INTO MONDAY. RAIN TOTALS WILL VARY GREATLY GIVEN THE CONVECTIVE NATURE...BUT MOST AREAS SHOULD SEE A HALF TO THREE QUARTERS OF INCH OF RAIN. THE SHOWERS AND STORMS WILL END FROM WEST TO EAST WITH THE FRONTAL PASSAGE MONDAY AFTERNOON INTO THE EVENING. COOLER AND LESS HUMID AIR WILL FILTER IN BEHIND THE FRONT. HIGHS IN THE 70S CAN BE EXPECTED FOR TUESDAY AS THE UPPER FLOW BECOMES NORTHWESTERLY. OUTSIDE CHANCE THAT A FEW SHOWERS MAY POP UP ACROSS CENTRAL LOWER TUESDAY DUE TO THE COOL AIR ALOFT. I DID NOT ADD THIS...BUT I DID INCREASE THE CLOUD COVER IN THE FORECAST. WE SHOULD SEE DIURNAL CU AT THE VERY LEAST...WHICH SHOULD BECOME BKN TO OVC AT TIMES DURING THE AFTERNOON. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 326 PM EDT SUN AUG 9 2015 FAIR WEATHER IS ANTICIPATED WEDNESDAY WITH A HIGH PRESSURE RIDGE CENTERED OVER THE LOWER GREAT LAKES REGION STILL IN CONTROL OF THE WX PATTERN. IT WILL TURN WARMER AND MORE HUMID THURSDAY IN SW FLOW OUT AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL BRING A CHANCE OF RAIN AND THUNDERSTORMS LATE THURSDAY THROUGH THURSDAY NIGHT INTO FRIDAY. FAIR WX WILL RETURN BEHIND THAT SYSTEM FOR FRIDAY NIGHT THROUGH THE WEEKEND AS A HIGH PRESSURE RIDGE BUILDS SLOWLY EAST ACROSS THE GREAT LAKES REGION. TEMPERATURES NEXT WEEKEND WILL AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 738 PM EDT SUN AUG 9 2015 A FEW SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE THIS EVENING. WITH THE WARM FRONT NEAR I-75 AT 21Z... IT WOULD SEEM THE JXN AND LAN TAF SITES HAVE THE GREATEST RISK OF THUNDERSTORMS EARLY THIS EVENING SO I PUT VCTS THERE. THAT CONVECTION AREA SHOULD BE EAST OF THE TAF SITES AFTER 02Z. I EXPECT JUST A VFR CIGS ACROSS THE AREA FROM THEN TILL AROUND 09Z OR SO. THE SOUTHERLY FLOW OF MOIST AIR INTO THE AREA COMBINED WITH NIGHT TIME COOLING WILL LEAD TO A LOW STRATUS DECK TOWARD MORNING BUT NOT MUCH IN THE WAY OF SHOWERS. THE FRONTAL CONVECTIVE BAND...BASED ON THE HRRR-CR FALLS APART OVERNIGHT BUT RE-FIRES AROUND 13-14Z NEAR THE LAKE MICHIGAN SHORE THAN MOVES EAST ACROSS THE CWA WITH THE COLD FRONT. SKIES SHOULD CLEAR LATE IN THE AFTERNOON AS DRY AIR BEHIND THE COLD FRONT REACHES THE AREA. && .MARINE... ISSUED AT 326 PM EDT SUN AUG 9 2015 RATHER QUIET CONDITIONS ARE EXPECTED ON THE TONIGHT INTO MONDAY. HOWEVER NORTHERLY WINDS WILL INCREASE BEHIND THE FRONT AND WAVES WILL BEGIN TO BUILD MONDAY EVENING INTO TUESDAY. PEAK WINDS AND WAVES SHOULD OCCUR INTO TUESDAY...AND WE MAY NEED A SMALL CRAFT ADVISORY BY TUESDAY AFTERNOON. WINDS AND WAVES SHOULD THEN DIMINISH LATE TUESDAY NIGHT. && .HYDROLOGY... ISSUED AT 326 PM EDT SUN AUG 9 2015 NO HYDRO IMPACTS ARE EXPECTED OVER THE NEXT WEEK. THE CHANCE FOR SCATTERED SHOWERS WILL INCREASE THROUGH THE AFTERNOON AND ESPECIALLY THE EVENING. RAIN CHANCES ARE HIGHEST THIS EVENING INTO MONDAY AFTERNOON ALONG WITH THE POTENTIAL FOR ISOLATED STORMS. STORM CHANCES WILL BE HIGHEST EARLY MONDAY AFTERNOON ACROSS THE EASTERN FORECAST AREA. WE COULD SEE A FEW STRONG STORMS AT THAT TIME CAPABLE OF LOCALLY HIGHER RAINFALL AMOUNTS. BUT IN GENERAL...WIDESPREAD RAINFALL IS FORECAST TO REMAIN BELOW 0.75 INCHES AND MOST LIKELY IN THE 0.25 TO 0.50 INCH RANGE. ANY RAINFALL TONIGHT INTO MONDAY WILL LIKELY BE BENEFICIAL FOR MOST. OUTLOOK...THE REST OF THE WORK WEEK LOOKS QUIET AND MAINLY DRY. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...JK SHORT TERM...JK LONG TERM...LAURENS AVIATION...WDM HYDROLOGY...EBW MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
746 PM EDT SUN AUG 9 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 308 PM EDT SUN AUG 9 2015 MUCH OF THE FOCUS ON THE SHORT TERM FORECAST IS ON THE CONVECTIVE DEVELOPMENT EXPECTED OVER THE WEST/CENTRAL U.P. IN THE NEXT FEW HOURS AND CONTINUING INTO THE EVENING. A LARGE AREA OF MVFR CLOUDS HAS BEEN SETUP OVER NORTHWEST WISCONSIN AND WESTERN UPPER MICHIGAN THIS MORNING AND INTO THE EARLY AFTERNOON HOURS. THIS HAS HELPED SUPPRESS THE DIURNAL HEATING AND HAS KEPT ML CAPE VALUES OVER THE WESTERN THIRD OF THE U.P. BELOW 500 J/KG. FARTHER TO THE EAST AND ALONG THE EDGE OF THE LOW CLOUDS...DIURNAL CU HAS DEVELOPED AND RAP ANALYSIS DATA IS SHOWING 500-1000 J/KG OF ML CAPE. HAVE STARTED TO SEE SOME SHOWERS DEVELOP IN CENTRAL IRON COUNTY AND ALSO ALONG THE WISCONSIN BORDER SOUTH OF BESSEMER. THESE ARE OUT AHEAD OF THE COLD FRONT STRETCHING SOUTHWEST ACROSS WESTERN LAKE SUPERIOR AND INTO CENTRAL MINNESOTA. A SHORTWAVE HAS BEEN MOVING THROUGH CENTRAL MINNESOTA THIS MORNING AND INTO THE EARLY AFTERNOON HOURS...WHICH HAS BEEN THE MAIN FOCUS OF SHOWERS AND THUNDERSTORMS THUS FAR. WITH THE SHORTWAVE EXPECTED TO CONTINUE EASTWARD...THINK THE CWA WILL ONLY BE BRUSHED BY THE NORTHERN EDGE...BUT WITH THE SUPPORT OF THE WEAK COLD FRONT MOVING INTO THE WESTERN U.P. STILL THINK ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE THE REST OF THIS AFTERNOON INTO THIS EVENING. RAP MUCAPE VALUES EXCEED 1000 J/KG OVER THE WESTERN U.P. SO THERE IS STILL SOME SUPPORT FOR STRONGER STORMS IF THEY CAN GET GOING. UNFORTUNATELY MID CLOUDS FROM THE SHORTWAVE ARE MASKING THE LOWER CLOUD FIELD AND IT IS MAKING IT DIFFICULT TO SEE HOW DEVELOPMENT IS GOING...BUT AM ABLE TO MAKE OUT SOME SCATTERING OF THE LOW CLOUDS TO THE SOUTHWEST OF MARQUETTE COUNTY...SO THAT MAY BE ENOUGH TO GET SHOWERS DEVELOPING FURTHER AS THEY INTERACT WITH THE BETTER INSTABILITY JUST TO THE EAST. IN ADDITION...HAVE SEEN SOME HINTS OF A LAKE BREEZE NEAR MARQUETTE ON OBS AND RADAR...WHICH WILL LEAD TO SOME SHOWER DEVELOPMENT. ADJUSTED THE FORECAST EARLIER THIS MORNING WITH THE AXIS OF HIGHEST POPS TOWARDS THAT AREA AND WILL MAKE SLIGHT ADJUSTMENTS TO THAT AREA (SLIGHTLY TO THE WEST AND TOWARDS THE COLD FRONT) BEFORE FINAL ISSUANCE. THE FRONT WILL SLOWLY MOVE EAST ACROSS THE U.P. TONIGHT AND EXIT THE NEWBERRY/MANISTIQUE AREA A COUPLE HOURS AFTER SUNRISE. A LOT OF THE FORECAST FOR THIS EVENING WILL DEPEND ON THE DEVELOPMENT/COVERAGE OF THE SHOWERS AND THUNDERSTORMS OVER THE WESTERN/CENTRAL U.P....BUT THINK THE COMBINED FRONT AND SHORTWAVE WILL KEEP THE SCATTERED SHOWER POTENTIAL PUSHING EAST THROUGH THE AREA INTO THE FIRST PART OF THE OVERNIGHT HOURS...ESPECIALLY OVER THE CENTRAL. THEN...EXPECT SHOWERS TO DIMINISH OVERNIGHT AS THE COLD FRONT AND WEAK SHORTWAVE SHIFTS OFF TO THE EAST. THAT WILL LEAVE THE AREA BETWEEN THE DEPARTING COLD FRONT AND A HIGH BUILDING INTO THE NORTHERN PLAINS. WITH LIGHT WINDS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES BEHIND THE FRONT...EXPECT THERE TO BE SOME FOG DEVELOPMENT OVERNIGHT...ESPECIALLY OVER THE CENTRAL. THE WEST AND EAST THIRDS WILL BE A LITTLE MORE UNCERTAIN...DUE TO THE POTENTIAL FOR LESS LOW LEVEL MOISTENING FROM RAIN AND CLOUD COVER FROM THE DEPARTING SHORTWAVE OVER THE EAST AND INCREASING LOW LEVEL NORTH-NORTHWESTERLY FLOW OVER THE WEST. THOSE NORTHERLY WINDS WILL INCREASE THROUGH THE MORNING TOMORROW AS THE FRONT MOVES AWAY FROM THE AREA AND THE HIGH BUILDS INTO THE NORTHERLY PLAINS. OVERALL...IT SHOULDN/T BE TOO WINDY WITH MOSTLY LOCATIONS SEEING GUSTS AROUND 10-12KTS. WITH THE WINDS AIDING MIXING AND DIURNAL HEATING...SHOULD SEE THE FOG THAT DEVELOPS OVERNIGHT TRANSITION TO SOME DIURNAL CU THROUGH THE MORNING AND EARLY AFTERNOON HOURS. MODELS SHOWING LIMITED MOISTURE THAT IT IS MIXING INTO...SO WOULDN/T EXPECT THE COVERAGE TO BE MORE THAN PARTLY CLOUDY. THERE CONTINUES TO BE INDICATIONS IN THE HIGHER RESOLUTION MODELS THAT ISOLATED SHOWERS WILL DEVELOP OVER THE SOUTH CENTRAL IN THE AFTERNOON AND ALSO AROUND OR JUST SOUTHEAST OF KERY. THERE IS BETTER MOISTURE LINGERING IN THAT AREA AND INDICATIONS OF MLCAPE VALUES RISING TOWARDS 300 J/KG. FINALLY...DEEPER MOISTURE ARRIVES LATE IN THE DAY FROM THE NORTHWEST AS A 700-500MB TROUGH DROPS SOUTHEAST AROUND THE DISSIPATING JAMES BAY UPPER LOW. WITH THE STRENGTH OF THE WAVE...COULD SEE A FEW SHOWERS DROP SOUTHEAST ACROSS NORTHWEST LAKE SUPERIOR LATE IN THE DAY AND MAYBE APPROACH THE KEWEENAW PENINSULA. HAVE LEFT THE SLIGHT CHANCES JUST TO THE NORTHWEST OF THE KEWEENAW FOR NOW...AS THE BEST OPPORTUNITY WOULD COME AFTER 00Z. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 332 PM EDT SUN AUG 9 2015 A NW FLOW BTWN AN UPR RDG IN THE PLAINS AND A DOWNSTREAM TROF OVER ERN CANADA WL DOMINATE THE GREAT LKS EARLY THIS WEEK...BRINGING A PERIOD OF BLO NORMAL TEMPS FOR MON NGT INTO WED. WARMER WX AND A CHC OF SHOWERS/TS WL THEN BE THE RULE ON THU IN ADVANCE OF A COLD FNT ASSOCIATED WITH A DISTURBANCE DROPPING SEWD THRU NW ONTARIO. EXPECT DRY AND A BIT COOLER WX LATE IN THE WEEK WITH HI PRES TRAILING THE FNT. THE NEXT CHC OF SHOWERS/TS AND WARMER WX WL RETURN NEXT SUN AHEAD OF THE NEXT SHRTWV/COLD FNT TOPPING THE PERSISTENT UPR RDG IN THE PLAINS. MON NGT...SHRTWV DIVING SEWD IN THE NW FLOW ALF BTWN PLAINS RDG AND ERN TROF IS FCST TO DIG THRU THE AREA. SOME OF THE MODELS SHOW SOME WEAK DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE PVA AHEAD OF THIS DISTURBANCE AND GENERATE SOME SPOTTY LGT PCPN OVER THE AREA...MAINLY OVER THE HIER TERRAIN NEAR LK SUP WITH UPSLOPE N WINDS. BUT ABSENCE OF STRONGER FORCING AND ARRIVAL OF THIS DISTURBANCE DURING PERIOD OF NOCTURNAL COOLING WL LIMIT INTENSITY AND COVERAGE OF ANY SHOWERS. DO EXPECT MORE LO CLDS IN THESE UPSLOPE AREAS WITH AN INCRS IN LLVL RH AS H85 TEMPS WITHIN THERMAL TROF FALL TO 8-10C BY 12Z TUE. STEADY N WINDS WL LIMIT THE DIURNAL TEMP FALL DESPITE THE LLVL COOLING TREND. MOST PLACES SHOULD SEE MINS IN THE 50S...WITH THE LOWER TEMPS AT THE COOLER SPOTS OVER THE INTERIOR W HALF WHERE THE WINDS WL BE A BIT LIGHTER CLOSER TO SFC HI PRES RDG BLDG INTO MN. TUE/TUE NGT...EXPECT DRY WX TO PREVAIL DURING THIS TIME UNDER CONFLUENT NW FLOW ALF/DEEP LYR QVECTOR DVGC/SUBSIDENCE LEFT IN THE WAKE OF EXITING SHRTWV. SC IN THE UPSLOPE AREAS ON TUE MRNG SHOULD EXPAND WITH DAYTIME HEATING UNDER THERMAL TROF...BUT CLOSER APRCH OF SFC HI PRES FCST TO ARRIVE OVER THE W BY 00Z WED/INCRSGLY ACYC LLVL FLOW/LOWERING SUBSIDENCE INVRN WL LIKELY RESULT IN MORE SUNSHINE W-E THRU THE AFTN. UNDER MOCLR SKIES...TUE NGT WL BE COOL ESPECIALLY OVER THE INTERIOR W HALF WITH LIGHTER WINDS CLOSER TO SFC HI PRES RDG SINKING INTO WI. BUT WITH MIN PWAT NOT MUCH BLO 0.75 INCH IN THIS AREA...DO NOT EXPECT MIN TEMPS TO BE TOO CHILLY. WED/WED NGT...SFC HI PRES IS FCST TO SINK S INTO THE MID MS RIVER VALLEY THRU THIS TIME. AS THE MSLP FALLS OVER NW ONTARIO IN ADVANCE OF SHRTWV RIDING OVER THE TOP OF PLAINS RDG INTO FAR NW ONTARIO... UPR MI WL BE DOMINATED BY AN INCRSG WSW FLOW. EXPECT SOME CLDS ASSOCIATED WITH BAND OF INCRSG WAA/ISENTROPIC ASCENT BEST SHOWN ON THE 300-305K SFCS TO IMPACT THE UPR LKS WED AFTN/EVNG. MANY OF THE MODELS GENERATE SOME PCPN AS WELL...BUT RELATIVE DRYNESS OF THE LLVLS AND MODEST PWAT FCST NEAR 1 INCH /ABOUT NORMAL/ WARRANT ONLY LO CHC POPS. THU/THU NGT...SHRTWV OVER FAR NW ONTARIO AT 12Z THU IS PROGGED TO SLIDE SE INTO WRN QUEBEC THU NGT AND DRAG A COLD FNT ACRS UPR MI SOMETIME THU AFTN/EVNG. ARRIVAL OF THIS BNDRY/BAND OF MODEST DEEP LYR FORCING AT A TIME WHEN DAYTIME HEATING WL HAVE AN IMPACT FAVORS SOME SHOWERS/TS...BUT ABSENCE OF MUCH IN THE WAY OF HGT FALLS WELL TO THE SW OF TRACK OF SHRTWV/SHARPEST FORCING...QUESTIONS ABOUT DEGREE OF MSTR INFLOW AHEAD OF THE FNT AND TIMING DIFFERENCES AMONG THE MODELS ON FROPA TIMING WARRANT NO HIER THAN LO CHC POPS ATTM. THU LOOKS TO BE A WARM DAY WITH H85 TEMPS PUSHING 18-20C AHEAD OF THE FNT. EXTENDED...HI PRES TRAILING THE COLD FROPA WL BRING MOCLR WX FOR FRI AND SAT. FRI WL BE COOLER WITH H85 TEMPS DIPPING TO ARND 14C...BUT THEN SAT WL TURN WARMER AS THE HI SHIFTS TO THE E AND RETURN SSW FLOW LIFTS H85 TEMPS UP TO 16C. THE NEXT CHC OF SHOWERS/TS WL ARRIVE ON SUN AHEAD OF NEXT DISTURBANCE RIDING OVER THE PLAINS RDG. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 746 PM EDT SUN AUG 9 2015 SCT SHOWERS INTO CENTRAL UPPER MICHIGAN THIS EVENING MAY STILL BRUSH KSAW BUT CONFIDENCE IN TSRA POTENTIAL WAS TOO LOW TO MENTION IN THE TAF. OTHERWISE...ONLY A FEW LINGERING LIGHT SHOWERS ARE POSSIBLE EARLY IN THE PERIOD AT CMX/IWD. ONCE THE COLD FRONT MOVES THROUGH THE AREA TONIGHT AND BREAKS IN THE CLOUDS OCCUR...EXPECT GROUND FOG MAY DEVELOP AT ALL THREE SITES...ESPECIALLY AT SAW WHERE RAIN FELL AND THE LIGHTEST WINDS ARE WILL OCCUR. THE FCST IS NOT AS PESSIMISTIC FOR THE WEST SITES...AS LOW LEVEL WINDS WILL SLOWLY BE INCREASING THROUGH THE NIGHT AND LEAD TO MORE MIXING INTO THE DRIER AIR ALOFT. FINALLY FOR TOMORROW...EXPECT CONDITIONS IMPROVING TO VFR THROUGH THE MORNING HOURS AS THE AREA IS IN BETWEEN THE DEPARTING FRONT AND ANOTHER UPPER LEVEL DISTURBANCE ARRIVING LATE MONDAY AFTERNOON AND EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 308 PM EDT SUN AUG 9 2015 A COLD FRONT MOVING ACROSS WEST-CENTRAL LAKE SUPERIOR AT THIS TIME WILL PUSH EAST ACROSS THE REST OF THE LAKE TONIGHT WILL LEAD TO A WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY A WEAK PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT THRU MON. PATCHY TO AREAS OF FOG HAS BEEN OBSERVED ON SATELLITE FOR PORTIONS OF THE LAKE AND EXPECT THAT TO DIMINISH TONIGHT INTO MONDAY AS SLIGHTLY DRIER AIR ARRIVES BEHIND THE FRONT. MON NIGHT/TUE...THE GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE SOME OUT OF THE SOUTHWEST INTO THU AHEAD OF THE NEXT APPROACHING COLD FRONT. THAT FRONT WILL SHIFT WINDS TO THE NORTHWEST FOR FRIDAY...BUT SHOULD STAY BELOW 20KTS AT HIGH PRESSURE BUILDS BACK OVER THE AREA. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KC AVIATION...JLB MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
316 PM EDT SAT AUG 8 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 250 PM EDT SAT AUG 8 2015 THE UPPER GREAT LAKES REGION WILL BE BETWEEN UPPER LEVEL FEATURES OVER THE NEXT 24 HOURS...LEADING TO SOME UNCERTAINTY IN THE COVERAGE AND AMOUNT OF PRECIPITATION THAT WILL OCCUR AHEAD OF THE COLD FRONT TONIGHT. THE MAIN SHORTWAVE IS CURRENTLY LOCATED JUST TO THE EAST OF LAKE WINNIPEG AND HAS A 1002MB SURFACE LOW LOCATED WITH IT. A COLD FRONT STRETCHES SOUTH-SOUTHEAST FROM THIS LOW AND INTO NORTHERN MINNESOTA (CURRENTLY FROM THE LAKE OF THE WOODS TO JUST TO THE EAST OF FARGO). HAVE SEEN SOME SHOWERS AND THUNDERSTORMS DEVELOP AROUND PARK RAPIDS MINNESOTA A COUPLE HOURS AGO AND THEY HAVE BEEN MAKING THERE WAY TO THE EAST TOWARDS LEECH LAKE AHEAD OF THAT FRONT AND IN THE RIBBON OF DEEPER MOISTURE FROM 925-700MB AHEAD OF THE ASSOCIATED TROUGH. OVER THE U.P....THE ABUNDANT DRY AIR SEEN ABOVE 700MB ON THE 12Z KGRB SOUNDING AND ON RAP ANALYSIS DATA...ASSOCIATED WITH THE SURFACE RIDGE FROM A HIGH NEAR JAMES BAY...HAS BEEN LIMITING THE EASTWARD EXTENT OF THE OF SHOWERS AS THEY MOVE INTO WESTERN LAKE SUPERIOR. BUT WITH THE MOISTURE BELOW 700MB...HAVE SEEN DIURNAL CU FILL IN THE GAPS FROM EARLIER TODAY BETWEEN THE SOUTHEASTERLY FLOW UPSLOPE FOG AND LOW CLOUDS. TEMPERATURES HAVE WARMED INTO THE 70S ACROSS THE AREA...WITH THE WARMEST VALUES OVER THE EAST WITH MORE SUNSHINE. FINALLY FARTHER TO THE SOUTH...A SHORTWAVE ROUNDING THE UPPER RIDGE OVER TEXAS/OKLAHOMA LED TO AN MCS MOVING THROUGH NORTHEAST KANSAS AND SOUTHWEST MISSOURI EARLY THIS MORNING AND IT HAS SINCE DISSIPATED. BUT WITH ANOTHER WAVE ROUNDING THE RIDGE THROUGH NEBRASKA...WOULD EXPECT REDEVELOPMENT TO THE EAST OF THAT AREA OVER THE NEXT COUPLE OF HOURS. WITH THE SOUTHERN SHORTWAVE STAYING WELL TO THE SOUTH OF THE AREA...THE MAIN FOCUS WILL BE WITH THE UPPER LOW NEAR LAKE WINNIPEG SLOWLY WEAKENING AS IT MOVES EAST TOWARDS JAMES BAY. THIS WILL LEAD TO THE SURFACE LOW FOLLOWING SUIT AND SLOWLY DRAGGING THE COLD FRONT EAST ACROSS THE CWA. HAVE ALREADY SEEN SHOWERS/THUNDERSTORMS DEVELOP IN NORTHERN MINNESOTA AHEAD OF THE FRONT AND WITH THE STORM MOTION VALUES INDICATING EASTWARD MOVEMENT UP TO 30KTS...WOULD EXPECT THE SHOWERS TO SPREAD EAST INTO WESTERN LAKE SUPERIOR AND EVENTUALLY THE WESTERN U.P. TONIGHT. LIKE LAST NIGHT AND TODAY...THEY WILL BE BATTLING THE EXISTING DRY MID LEVEL AIR AS THEY MOVE OUT AHEAD OF THE SLOW MOVING SURFACE-850MB TROUGH...SO WOULD EXPECT SOME DIMINISHMENT AS THEY HEAD TO THE EAST AND INTO THE CWA TONIGHT. WOULD EXPECT SOME MARGINALLY SEVERE STORMS TO MOVE INTO WESTERN LAKE SUPERIOR BEFORE THE DRY AIR AND LOSS OF DIURNAL HEATING STARTS TO TAKE ITS TOLL. OVER THE CENTRAL AND EASTERN U.P....AM EXPECTED SOME PATCHY GROUND FOG TO DEVELOP TONIGHT. THICKNESS WILL DEPEND ON THE AMOUNT OF DECOUPLING THAT OCCURS TONIGHT. HAVE SHOWN THE THICKEST FOG (AREAS COVERAGE) OVER THE CENTRAL U.P. FOR SOUTHERN MARQUETTE...DICKINSON...DELTA...AND NORTHERN MENOMINEE COUNTIES. WITH THE COLD FRONT STILL OFF TO THE WEST OF THE U.P. ON SUNDAY MORNING...EXPECT THERE TO BE TIME FOR DIURNAL HEATING TO INCREASE THE POTENTIAL FOR SHOWERS/THUNDERSTORMS OVER THE WEST/CENTRAL U.P. DURING THE AFTERNOON. MODELS HAVE A VARIETY OF IDEAS ON ML CAPE VALUES...RANGING FROM 250-2000 J/KG TOMORROW AFTERNOON JUST AHEAD OF THE FRONT. LOOKING AT MODIFIED SOUNDINGS AND MEAN ML CAPE VALUES FROM THE NCAR ENSEMBLES AND SREF...FEEL THAT VALUES AROUND 500-750 J/KG ARE A FAIRLY REASONABLE EXPECTATION AT THIS POINT. WITH 0-6KM BULK SHEAR VALUES GENERALLY AROUND 25-30KTS...THERE IS THE POTENTIAL FOR AN ISOLATED STRONGER STORM TOMORROW AFTERNOON. THAT MATCHES THE IDEA FROM UPDRAFT VELOCITY/HELICITY FROM THE CAM/S AND CAM ENSEMBLES. WITH WET BULB ZERO VALUES NEARING 10KFT AND FREEZING LEVEL ABOVE 12KFT...THINK THAT WILL COMBINE WITH THE MARGINAL SHEAR TO KEEP THE HAIL THREAT BORDERLINE. LIKED THE PREVIOUS SHIFTS HANDLING OF THE DEVELOPMENT OF THE SHOWERS/THUNDERSTORMS ACROSS THE CENTRAL U.P. (RAMPING UP TO LOCALIZED LIKELY VALUES OVER MARQUETTE COUNTY) AND HAVE ONLY MADE MINOR ADJUSTMENTS BASED OFF LATEST MODEL TRENDS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 315 PM EDT SAT AUG 8 2015 AFTER ANY LINGERING SHOWERS END ON MON FOLLOWING A SUN NGT COLD FROPA...THE NW FLOW BTWN A BLDG UPR RDG IN THE PLAINS AND AN AMPLIFYING TROF OVER ERN NAMERICA WL BE THE DOMINATING INFLUENCE ON UPR MI WX EARLY IN THE WEEK. THE RESULT WL BE A RETURN OF DRY AND COOLER WX FOR THE MOST PART MON INTO WED. THE NEXT CHC OF SHOWERS/TS WL ARRIVE WITH WARMER AIR WED NGT THRU THU NGT AHEAD OF A SHRTWV MOVING OVER THE TOP OF THE RDG/THRU NW ONTARIO AND ITS ATTENDANT COLD FNT. HI PRES TRAILING THIS COLD FNT SHOULD BRING A SEASONABLE AIRMASS/DRIER WX LATE IN THE WEEK. SUN NGT...SHRTWV DRIFTING ESEWD THRU FAR NORTHERN ONTARIO WL REACH NEAR JAMES BAY BY 12Z MON AND DRAG ATTENDANT COLD FNT SLOWLY THRU THE UPR LKS. SINCE THE SHARPER DYNAMIC FORCING ASSOCIATED WITH THE ONTARIO SHRTWV WL BE REMAIN TO THE N AND H85 THETA E ADVECTION/ DEEPER MSTR INFLOW WL BE WEAK AT BEST...EXPECT NO MORE THAN A CHC OF SHOWERS/TS. THE BEST CHC FOR THIS PCPN WL BE IN THE EVNG OVER CENTRAL UPR MI...WHERE AXIS OF SOMEWHAT HIER H85 THETA E WL BE PRESENT AT TIME WHEN DAYTIME HEATING WL STILL BE A FACTOR. THE MAJORITY OF THE MODELS SHOW A TRAILING SHRTWV/AREA OF HIER MID LVL MSTR/SOME DPVA AND H7-3 QVECTOR CNVGC APRCHG FM CENTRAL MN FOLLOWING THE COLD FROPA. HOWEVER...NOCTURNAL COOLING AND LLVL DRYING/ NEGATIVE H85 THETA E ADVCTN WL LIMIT THE COVERAGE/INTENSITY OF ANY SHOWERS THAT MIGHT ACCOMPANYING THIS HIER LVL FORCING. EXPECT THE LOWEST MIN TEMPS OVER THE W...WHERE H85 TEMPS ARE FCST TO FALL TO ARND 11C BY DAYBREAK. MON...EXPECT ANY LINGERING SHOWERS OVER THE E AND SCENTRAL TO DIMINISH WITH ARRIVAL OF DEEP DRYING/INCRSG LLVL ACYC NNW FLOW AHEAD OF CNDN HI PRES BLDG INTO MANITOBA. LINGERING MID CLDS WL GIVE WAY TO SOME DIURNAL CU/SC IN THE AFTN. EXPECT HI TEMPS MAINLY IN THE 70S TO NEAR 80 OVER THE SCNTRL WITH H85 TEMPS IN THE 12-14C RANGE. LOCATIONS NEAR LK SUP WL BE COOLEST WITH A NW FLOW OFF THE WATER. MON NGT THRU TUE NGT...ARRIVAL OF MORE VIGOROUS DEEP LYR QVECTOR DVGC/SUBSIDENCE UNDER CONFLUENT NW FLOW ALOFT BTWN PLAINS RDG/ERN TROF AND H85 TEMPS FALLING AS LO AS 8 TO 10C IN THE LLVL NLY FLOW AHEAD OF CNDN HI PRES BLDG TOWARD THE UPR LKS WL RESULT IN A PERIOD OF COOLER AND DRIER WX FOR THE CWA. SOME OF THE MODELS HAVE BEEN GENERATING SOME LGT PCPN MAINLY DURING DAYTIME HEATING ON TUE ACCOMPANYING THE PASSAGE OF A SHRTWV IN THE NW FLOW. BUT ABSENCE OF ANY MSTR INFLOW...LARGER SCALE NEGATIVE DYNAMIC FORCING/SUBSIDENCE THAT WL MAINTAIN MID LVL CAPPING SHOWN ON THE GFS FCST SDNGS AS WELL AS DIFFLUENT LLVL FLOW WARRANTS MAINTAINING GOING DRY FCST FOR NOW. BUT THERE WL BE A GOOD DEAL OF DIURNAL CU ON TUE UNDER INCOMING H85 THERMAL TROF. EXPECT LO TEMPS ON TUE NGT TO FALL INTO THE 40S AT THE COOLER INTERIOR LOCATIONS WITH MOCLR SKIES/LIGHT WINDS AS THE SFC HI PRES MOVES OVHD. WED...AS THE HI CENTER DRIFTS TO THE S...THE LLVL FLOW WL TURN TO THE WSW. THE WARMING RELATED TO SOME WAA AND CONTINUED SUBSIDENCE UNDER THE SLOWLY EXPANDING PLAINS RDG/RISING HGTS IS FCST TO BOOST H85 TEMPS TO ARND 16C OVER THE W LATE IN THE DAY. EXPECT A WARMER DAY THAN ON TUE...WITH HI TEMPS AT LEAST APRCHG 80 ESPECIALLY OVER THE W AWAY FM LK MODERATION...EVEN IF SOME WAA CLDS SPILL OVER THE CWA IN THE AFTN. WED NGT THRU THU NGT...ALTHOUGH THERE ARE SOME DIFFERENCES IN THE DETAILS AS EXPECTED SO FAR INTO THE FUTURE...THE LONGER RANGE GUIDANCE INDICATES A SHRTWV RIDING OVER THE PLAINS RDG WL DROP SEWD THRU NW ONTARIO ON THU/THU NGT AND DRAG A COLD FNT THRU THE UPR LKS ON THU NGT. SOME OF THE MODELS GENERATE SOME LGT PCPN AS EARLY AS WED NGT IN THE WSW FLOW/WAA BTWN THE RETREATING HI PRES TO THE S AND FALLING MSLP OVER SCENTRAL CANADA AHEAD OF THE SHRTWV. BUT LINGERING LLVL ACYC FLOW AND RELATIVE DRYNESS OF AIRMASS INDICATE ANY SHOWERS WL BE WIDELY SCT AT BEST. A BETTER CHC FOR SHOWERS/TS APPEARS WL COME LATE THU/THU EVNG WITH THE ARRIVAL OF SOME DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE ONTARIO SHRTWV AND AHEAD OF APRCHG COLD FNT DURING PERIOD OF DAYTIME HEATING. THE 12Z GFS IS MOST VIGOROUS WITH THIS DISTURBANCE AND INDICATES THE POTENTIAL FOR SOME SVR STORMS WITH MUCAPE FCST AS HI AS 2500 J/KG AND DEEP LYR SHEAR UP TO 40 KTS. THE 12Z ECMWF/CNDN MODELS SHOW A LESS IMPRESSIVE SCENARIO WITH WEAKER MSTR RETURN. GIVEN MODEL DIFFERENCES AND UNCERTAINTY ON THE DEGREE OF MSTR RETURN WITH SHARPEST FORCING REMAINING TO THE NE...CONSENSUS LO CHC POPS AT THIS POINT SEEM REASONABLE. THU LOOKS TO BE THE WARMEST DAY OF THE WEEK UNDER THERMAL RDG/H85 TEMPS UP TO 18-20C AHEAD OF INCOMING COLD FNT. FRI/SAT...HI PRES TRAILING THE SHRTWV SHOULD BRING DRY AND SOMEWHAT COOLER WX AT LEAST ON FRI/FRI NGT. THERE IS SOME UNCERTAINTY ON HOW QUICKLY WAA SHOWERS/TS RETURN BTWN THE RETREATING HI AND ANOTHER SHRTWV RIDING OVER THE PLAINS RDG LATER ON SAT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 150 PM EDT SAT AUG 8 2015 VFR DIURNAL CLOUDS WILL BE THE MAIN SHORT TERM CONCERN. THESE CEILINGS HAVE BEEN GRADUALLY RISING WITH DAYTIME HEATING AND MIXING AND EXPECT THAT TO CONTINUE INTO THE AFTERNOON AND THE HIGH END MVFR CEILINGS SHOULD TRANSITION TO VFR WITHIN THE NEXT COUPLE HOURS. OTHERWISE...A COLD FRONT FROM MINNESOTA THAT WILL MOVE ACROSS THE AREA ON SUNDAY MAY PUSH A COUPLE SHOWERS THROUGH THE WESTERN HALF OF UPPER MICHIGAN AND ONLY HAD ENOUGH CONFIDENCE TO INCLUDE VCSH AT KCMX OVERNIGHT AND LATE IN THE PERIOD AT KSAW. ALSO FOR KSAW...DEPENDING ON THE AMOUNT OF SCATTERING OF THE CLOUDS THIS EVENING...COULD SEE LIFR-IFR CONDITIONS DEVELOP WITH PATCHY GROUND FOG OVERNIGHT TONIGHT. HAVE WENT WITH LOW END MVFR VISIBILITIES FOR NOW...BUT WILL BE SOMETHING TO MONITOR. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 250 PM EDT SAT AUG 8 2015 A LOW MOVING FROM JUST EAST OF LAKE WINNIPEG TO JAMES BAY THIS WEEKEND WILL SWEEP A SURFACE TROUGH ACROSS LAKE SUPERIOR ON SUNDAY...LEADING TO A SHIFT IN THE WINDS FROM A LIGHT SOUTH TO SOUTHEASTERLY DIRECTION TO THE NORTHWEST BY MONDAY. WITH A GENERALLY LIGHT PRESSURE GRADIENT IN PLACE...EXPECT WINDS TO STAY BELOW 20KTS THROUGH THE PERIOD...ESPECIALLY AFTER TUESDAY WHEN HIGH PRESSURE WILL SETTLE OVER THE GREAT LAKES REGION FOR THE MIDDLE OF NEXT WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KC AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
250 PM EDT SAT AUG 8 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 250 PM EDT SAT AUG 8 2015 THE UPPER GREAT LAKES REGION WILL BE BETWEEN UPPER LEVEL FEATURES OVER THE NEXT 24 HOURS...LEADING TO SOME UNCERTAINTY IN THE COVERAGE AND AMOUNT OF PRECIPITATION THAT WILL OCCUR AHEAD OF THE COLD FRONT TONIGHT. THE MAIN SHORTWAVE IS CURRENTLY LOCATED JUST TO THE EAST OF LAKE WINNIPEG AND HAS A 1002MB SURFACE LOW LOCATED WITH IT. A COLD FRONT STRETCHES SOUTH-SOUTHEAST FROM THIS LOW AND INTO NORTHERN MINNESOTA (CURRENTLY FROM THE LAKE OF THE WOODS TO JUST TO THE EAST OF FARGO). HAVE SEEN SOME SHOWERS AND THUNDERSTORMS DEVELOP AROUND PARK RAPIDS MINNESOTA A COUPLE HOURS AGO AND THEY HAVE BEEN MAKING THERE WAY TO THE EAST TOWARDS LEECH LAKE AHEAD OF THAT FRONT AND IN THE RIBBON OF DEEPER MOISTURE FROM 925-700MB AHEAD OF THE ASSOCIATED TROUGH. OVER THE U.P....THE ABUNDANT DRY AIR SEEN ABOVE 700MB ON THE 12Z KGRB SOUNDING AND ON RAP ANALYSIS DATA...ASSOCIATED WITH THE SURFACE RIDGE FROM A HIGH NEAR JAMES BAY...HAS BEEN LIMITING THE EASTWARD EXTENT OF THE OF SHOWERS AS THEY MOVE INTO WESTERN LAKE SUPERIOR. BUT WITH THE MOISTURE BELOW 700MB...HAVE SEEN DIURNAL CU FILL IN THE GAPS FROM EARLIER TODAY BETWEEN THE SOUTHEASTERLY FLOW UPSLOPE FOG AND LOW CLOUDS. TEMPERATURES HAVE WARMED INTO THE 70S ACROSS THE AREA...WITH THE WARMEST VALUES OVER THE EAST WITH MORE SUNSHINE. FINALLY FARTHER TO THE SOUTH...A SHORTWAVE ROUNDING THE UPPER RIDGE OVER TEXAS/OKLAHOMA LED TO AN MCS MOVING THROUGH NORTHEAST KANSAS AND SOUTHWEST MISSOURI EARLY THIS MORNING AND IT HAS SINCE DISSIPATED. BUT WITH ANOTHER WAVE ROUNDING THE RIDGE THROUGH NEBRASKA...WOULD EXPECT REDEVELOPMENT TO THE EAST OF THAT AREA OVER THE NEXT COUPLE OF HOURS. WITH THE SOUTHERN SHORTWAVE STAYING WELL TO THE SOUTH OF THE AREA...THE MAIN FOCUS WILL BE WITH THE UPPER LOW NEAR LAKE WINNIPEG SLOWLY WEAKENING AS IT MOVES EAST TOWARDS JAMES BAY. THIS WILL LEAD TO THE SURFACE LOW FOLLOWING SUIT AND SLOWLY DRAGGING THE COLD FRONT EAST ACROSS THE CWA. HAVE ALREADY SEEN SHOWERS/THUNDERSTORMS DEVELOP IN NORTHERN MINNESOTA AHEAD OF THE FRONT AND WITH THE STORM MOTION VALUES INDICATING EASTWARD MOVEMENT UP TO 30KTS...WOULD EXPECT THE SHOWERS TO SPREAD EAST INTO WESTERN LAKE SUPERIOR AND EVENTUALLY THE WESTERN U.P. TONIGHT. LIKE LAST NIGHT AND TODAY...THEY WILL BE BATTLING THE EXISTING DRY MID LEVEL AIR AS THEY MOVE OUT AHEAD OF THE SLOW MOVING SURFACE-850MB TROUGH...SO WOULD EXPECT SOME DIMINISHMENT AS THEY HEAD TO THE EAST AND INTO THE CWA TONIGHT. WOULD EXPECT SOME MARGINALLY SEVERE STORMS TO MOVE INTO WESTERN LAKE SUPERIOR BEFORE THE DRY AIR AND LOSS OF DIURNAL HEATING STARTS TO TAKE ITS TOLL. OVER THE CENTRAL AND EASTERN U.P....AM EXPECTED SOME PATCHY GROUND FOG TO DEVELOP TONIGHT. THICKNESS WILL DEPEND ON THE AMOUNT OF DECOUPLING THAT OCCURS TONIGHT. HAVE SHOWN THE THICKEST FOG (AREAS COVERAGE) OVER THE CENTRAL U.P. FOR SOUTHERN MARQUETTE...DICKINSON...DELTA...AND NORTHERN MENOMINEE COUNTIES. WITH THE COLD FRONT STILL OFF TO THE WEST OF THE U.P. ON SUNDAY MORNING...EXPECT THERE TO BE TIME FOR DIURNAL HEATING TO INCREASE THE POTENTIAL FOR SHOWERS/THUNDERSTORMS OVER THE WEST/CENTRAL U.P. DURING THE AFTERNOON. MODELS HAVE A VARIETY OF IDEAS ON ML CAPE VALUES...RANGING FROM 250-2000 J/KG TOMORROW AFTERNOON JUST AHEAD OF THE FRONT. LOOKING AT MODIFIED SOUNDINGS AND MEAN ML CAPE VALUES FROM THE NCAR ENSEMBLES AND SREF...FEEL THAT VALUES AROUND 500-750 J/KG ARE A FAIRLY REASONABLE EXPECTATION AT THIS POINT. WITH 0-6KM BULK SHEAR VALUES GENERALLY AROUND 25-30KTS...THERE IS THE POTENTIAL FOR AN ISOLATED STRONGER STORM TOMORROW AFTERNOON. THAT MATCHES THE IDEA FROM UPDRAFT VELOCITY/HELICITY FROM THE CAM/S AND CAM ENSEMBLES. WITH WET BULB ZERO VALUES NEARING 10KFT AND FREEZING LEVEL ABOVE 12KFT...THINK THAT WILL COMBINE WITH THE MARGINAL SHEAR TO KEEP THE HAIL THREAT BORDERLINE. LIKED THE PREVIOUS SHIFTS HANDLING OF THE DEVELOPMENT OF THE SHOWERS/THUNDERSTORMS ACROSS THE CENTRAL U.P. (RAMPING UP TO LOCALIZED LIKELY VALUES OVER MARQUETTE COUNTY) AND HAVE ONLY MADE MINOR ADJUSTMENTS BASED OFF LATEST MODEL TRENDS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 506 AM EDT SAT AUG 8 2015 DURING THE LONG TERM...MID LEVEL LOW CURRENTLY OVER SRN MANITOBA IS FCST TO MOVE SLOWLY E INTO NRN ONTARIO BY SUN MORNING. AS THIS FEATURE CONTINUES TO SHIFT SLOWLY E...A BUILDING RIDGE TO THE LEE OF THE ROCKIES WILL FORCE A DEEPENING TROF INTO ERN NAMERICA DURING THE FIRST HALF OF NEXT WEEK. THIS TROF WILL LIKELY LINGER THRU THE REST OF THE WEEK. PRIOR TO THE DEEPENING TROF...A SERIES OF SHORTWAVES TRACKING ACROSS THE PLAINS TO THE GREAT LAKES WILL PROVIDE SOME OPPORTUNITY FOR SHRA/TSTMS. DEEPENING ERN TROF AND RESULTING NW FLOW INTO THE GREAT LAKES DURING THE FIRST HALF OF NEXT WEEK WILL THEN BRING DRY WEATHER. HOWEVER...TYPICAL FOR SUMMERTIME NW FLOW...ANY SUBTLE SHORTWAVE DROPPING THRU THE AREA COULD SPARK ISOLD AFTN CONVECTION. PCPN CHANCES WILL RETURN LATE IN THE WEEK AS THERE ARE INDICATIONS OF A DECENT SHORTWAVE ROUNDING THE WRN PLAINS RIDGE AND THEN DROPPING INTO THE ERN TROF. THIS WOULD RESULT IN POSSIBLE CONVECTION WITH LOW-LEVEL JET/WAA REGIME AHEAD OF WAVE AND ALSO WITH COLD FRONT THAT WOULD DROP S INTO THE GREAT LAKES. AS FOR TEMPS... AFTER READINGS NOT TOO FAR FROM NORMAL (ON THE WARM SIDE OF NORMAL FOR MOST LOCATIONS)...DEVELOPING NW FLOW EARLY NEXT WEEK WILL DROP TEMPS TO BLO NORMAL...BUT NOT SIGNIFICANTLY AS THERE WON`T BE A TAP OF CHILLY AIR FROM NORTHERN CANADA. ABOVE NORMAL TEMPS WILL RETURN BY THU AHEAD OF THE AFOREMENTIONED SHORTWAVE ROUNDING THE RIDGE. SOME COOLING SHOULD THEN FOLLOW BY THE WEEKEND...DEPENDING ON HOW SHARPLY THE SHORTWAVE DROPS INTO THE ERN TROF. BEGINNING SUN/SUN NIGHT...MID LEVEL LOW CURRENTLY OVER SRN MANITOBA WILL HAVE OPENED UP AND WILL BE DRIFTING ACROSS NRN ONTARIO. TO THE S OF THIS FEATURE...THERE REMAINS UNCERTAINTY IN THE WEAKER SHORTWAVE ENERGY TRACKING ACROSS THE PLAINS TO THE GREAT LAKES... PARTICULARLY WITH RESPECT TO WHERE CONVECTION WILL BE FIRING WITH THESE MORE SUBTLE FEATURES. HOWEVER...THERE HAS BEEN A FAIRLY CONSISTENT SIGNAL IN THE MODELS FOR A SUBTLE SFC WAVE AND MORE SUBSTANTIAL CONVECTIVE ACTIVITY TRACKING EASTWARD FROM VCNTY OF IA EARLY SUN ON THE NRN EDGE OF STRONG INSTABILITY IN THAT AREA. THIS WILL HELP KEEP STRONG INSTABILITY FROM BUILDING N ALONG COLD FRONT THAT WILL BE MOVING INTO THE UPPER LAKES SUN/SUN NIGHT IN ASSOCIATION WITH THE NRN ONTARIO SHORTWAVE. AHEAD OF APPROACHING COLD FRONT...NAM/GFS SHOW MLCAPE INCREASING TO ROUGHLY 500 TO 1500J/KG OVER THE W HALF OF UPPER MI SUN (NAM AS HIGH AS 2000J/KG). WHILE THERE MAY BE A FEW SHRA IN THE MORNING...APPROACHING COLD FRONT AND WEAK DEEP LAYER QVECTOR CONVERGENCE SHOULD SPARK SCT CONVECTION IN THE AFTN WHICH WILL THEN SPREAD E INTO SUN NIGHT ALONG/AHEAD OF PASSING COLD FRONT. WITH DEEP LAYER SHEAR NO GREATER THAN AROUND 25KT...NOT ANTICIPATING ANY SVR STORMS. HOWEVER...IF INSTABILITY ENDS UP AT OR ABOVE THE HIGH END OF THE CURRENTLY EXPECTED RANGE...COULDN`T RULE OUT A BRIEF ISOLD SVR STORM. LATEST SPC OUTLOOKS DO NOT HIGHLIGHT UPPER MI FOR A SVR RISK SUN/SUN NIGHT...AND THAT LOOKS RIGHT ON TRACK. ON MON...COLD FRONT SHOULD BE JUST E OF THE FCST AREA AT 12Z... ENDING THE RISK OF MORE ORGANIZED PCPN. THE NAM STILL MANAGES TO BUILD MLCAPE UPWARDS OF 1500J/KG OVER THE SCNTRL AND E...BUT THE GFS SHOWS LESS THAN 50J/KG. SINCE OTHER MODELS SUPPORT THE GFS WITH A STRONGER PRES GRADIENT BTWN HIGH PRES BUILDING INTO THE NRN PLAINS AND LOW PRES/COLD FRONT TO THE E...WILL FAVOR THE THE DRIER/LACK OF INSTABILITY GFS SOLUTION. WILL LINGER SCHC POPS FOR SHRA OVER THE E EARLY. OTHERWISE...PLAN TO CARRY A DRY FCST ON MON. EXPECT HIGHS IN THE 70S...BUT IT WILL BE COOLER NEAR LAKE SUPERIOR...ESPECIALLY OVER THE E UNDER NNW WINDS THERE. MON NIGHT THRU WED...BUILDING UPPER RIDGE WITH AXIS ROUGHLY OVER THE WRN HIGH PLAINS WILL FORCE A DEEPENING ERN NAMERICA TROF AND NW FLOW OVER THE GREAT LAKES...RESULTING IN COOLER WEATHER...BUT ONLY A LITTLE BLO NORMAL FOR EARLY/MID AUG. IN THE INTERIOR...NIGHTTIME MIN TEMPS WILL PROBABLY BE IN THE 40S IN THE USUAL COOL SPOTS. THERE CONTINUES TO BE SOME INDICATION OF A WEAK SHORTWAVE DROPPING THRU THE UPPER LAKES ON TUE WHICH COULD GENERATE A FEW ISOLD SHRA WITH DAYTIME HEATING. AT THIS POINT...THE POTENTIAL IS STILL LOW ENOUGH TO PRECLUDE A MENTION OF PCPN IN THE FCST FOR TUE. WITH UPPER TROF SHIFTING A BIT FARTHER E ON WED AND SFC HIGH PRES MORE FIRMLY OVER THE AREA...DRY WEATHER IS EXPECTED TO CONTINUE. MAX TEMPS WILL BE A LITTLE HIGHER ON WED. THU/FRI...TRENDS IN MEDIUM RANGE GUIDANCE ARE FOR A STRONGER SHORTWAVE TO CUT THRU THE NRN PORTION OF THE WRN RIDGE AND THEN DROP MORE SHARPLY TO THE SE INTO THE ERN NAMERICA TROF LATE NEXT WEEK. IF THIS TREND CONTINUES WITH THE NEXT SET OF MEDIUM RANGE GUIDANCE... THEN SHRA/TSTM CHANCES WILL NEED TO BE INCREASED FOR THU...WITH PCPN POSSIBLE AS EARLY AS WED DEPENDING ON WHERE WAA IS FOCUSED AHEAD OF THE SHORTWAVE. THE 00Z ECWMF/GFS INDICATE COLD FRONT WILL BE S OF THE AREA BY FRI...LEADING TO A DRY DAY AND SOME COOLING. WILL WAIT TO SEE IF THESE TRENDS FOR THU/FRI HOLD UP IN THE NEXT ROUND OF GUIDANCE BEFORE SHIFTING FCST MORE STRONGLY TOWARD THIS SOLUTION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 150 PM EDT SAT AUG 8 2015 VFR DIURNAL CLOUDS WILL BE THE MAIN SHORT TERM CONCERN. THESE CEILINGS HAVE BEEN GRADUALLY RISING WITH DAYTIME HEATING AND MIXING AND EXPECT THAT TO CONTINUE INTO THE AFTERNOON AND THE HIGH END MVFR CEILINGS SHOULD TRANSITION TO VFR WITHIN THE NEXT COUPLE HOURS. OTHERWISE...A COLD FRONT FROM MINNESOTA THAT WILL MOVE ACROSS THE AREA ON SUNDAY MAY PUSH A COUPLE SHOWERS THROUGH THE WESTERN HALF OF UPPER MICHIGAN AND ONLY HAD ENOUGH CONFIDENCE TO INCLUDE VCSH AT KCMX OVERNIGHT AND LATE IN THE PERIOD AT KSAW. ALSO FOR KSAW...DEPENDING ON THE AMOUNT OF SCATTERING OF THE CLOUDS THIS EVENING...COULD SEE LIFR-IFR CONDITIONS DEVELOP WITH PATCHY GROUND FOG OVERNIGHT TONIGHT. HAVE WENT WITH LOW END MVFR VISIBILITIES FOR NOW...BUT WILL BE SOMETHING TO MONITOR. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 250 PM EDT SAT AUG 8 2015 A LOW MOVING FROM JUST EAST OF LAKE WINNIPEG TO JAMES BAY THIS WEEKEND WILL SWEEP A SURFACE TROUGH ACROSS LAKE SUPERIOR ON SUNDAY...LEADING TO A SHIFT IN THE WINDS FROM A LIGHT SOUTH TO SOUTHEASTERLY DIRECTION TO THE NORTHWEST BY MONDAY. WITH A GENERALLY LIGHT PRESSURE GRADIENT IN PLACE...EXPECT WINDS TO STAY BELOW 20KTS THROUGH THE PERIOD...ESPECIALLY AFTER TUESDAY WHEN HIGH PRESSURE WILL SETTLE OVER THE GREAT LAKES REGION FOR THE MIDDLE OF NEXT WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...ROLFSON AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT SAT AUG 8 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 254 PM EDT FRI AUG 7 2015 A SHORTWAVE HAS UNDERCUT THE UPPER RIDGE OVER THE UPPER MISSISSIPPI VALLEY AND IS NOW DIVING SOUTHEAST ACROSS EASTERN WISCONSIN. THAT WAVE IS SUPPORTING THE SHOWERS AND A FEW EMBEDDED THUNDERSTORMS MOVING ACROSS THAT AREA. FARTHER TO THE WEST...A 1008MB SURFACE LOW IS LOCATED NEAR EAU CLAIRE WISCONSIN. TO THE NORTHEAST OF THE SURFACE LOW...AN AREA OF SHOWERS ARE MOVING EAST ACROSS UPPER MICHIGAN AT THIS TIME...TIED TO THE NORTHERN EDGE OF THE 850-700MB Q- VECTOR CONVERGENCE AND BROAD WARM AIR ADVECTION. THE HEAVIEST RAIN SO FAR TODAY HAS FALLEN OVER THE WESTERN HALF OF THE U.P....WITH 0.5 TO 0.65 INCHES OF RAIN FALLING OVER THE BARAGA PLAINS TODAY. AMOUNTS DIMINISH TO A TENTH OF AN INCH THROUGH 2PM FROM NEGAUNEE SOUTH TO IRON MOUNTAIN AND EVEN LESS FARTHER TO THE EAST. THE SURFACE LOW AND SHORTWAVE WILL SLOWLY DISSIPATE AS THEY MOVE TO THE EAST-SOUTHEAST TONIGHT...LIMITING THE INFLUENCE OF BOTH FEATURES THROUGH THE NIGHT. EXPECT THE SHOWERS TO DIMINISH AND DRIFT TO THE SOUTHEAST THROUGH THE EVENING (TIED TO THE 850-700MB Q-VECTOR CONVERGENCE)...AND LARGELY BE OUT OF THE CWA AROUND 06Z. BUT WITH THE MODELS CONTINUING TO SHOW LOW LEVEL MOISTURE PIVOTING TO THE NORTHWEST ON THE NORTHEAST SIDE OF THE 925-850 TROUGH IN CENTRAL/NORTHERN WISCONSIN...EXPECT ABUNDANT LOW CLOUDS TO BE IN PLACE ACROSS THE AREA. THESE LOW CLOUDS CAN ALREADY BE SEEN OVER EASTERN MINNESOTA AND WESTERN WISCONSIN...AND THEY HAVE BEEN WORKING INTO WESTERN UPPER MICHIGAN THROUGH THE DAY. THINK DRYING AND INCREASING SUBSIDENCE ABOVE THAT...GENERALLY ABOVE 750MB OVER THE WEST...WILL ALSO HELP THE DIMINISHMENT OF THE WIDESPREAD SHOWERS. DID HOLD ONTO THE SHOWERS A LITTLE LONGER OVER THE HIGHER TERRAIN UPSLOPE AREAS IN CENTRAL UPPER MICHIGAN DUE TO THE FAVORABLY SOUTHEASTERLY FLOW...BUT THE PRECIPITATION MAY FALL MORE AS DRIZZLE THAN RAIN. IN ADDITION...HAVE TRENDED FOG UP TO AREAS TO WIDESPREAD VALUES OVER THE WEST/CENTRAL U.P. WHERE THE BETTER RAIN HAS FALLEN AND TIED TO THE LOWEST 5KFT BEING SATURATED ON THE NAM/GFS SOUNDINGS. ONE ITEM TO WATCH...THE LATEST RAP RUNS HAVE BEEN HOLDING ONTO DRIER NEAR SURFACE AIR OVER THE NORTH CENTRAL...WHICH WOULD GREATLY REDUCE THE POTENTIAL FOR LOW CLOUDS AND FOG. EXPECT THE LOW LEVEL MOISTURE TO HOLD ON THROUGH THE FIRST HALF OF SATURDAY OVER THE WESTERN HALF TO TWO-THIRDS OF THE U.P. BEFORE THE CONTINUED SUBSIDENCE AND INFLUX OF DRIER AIR TRIES TO BREAK OF THE CLOUDS. WHILE THAT SHOULD RAISE THE CEILINGS ACROSS THE AREA...STILL EXPECT THE WESTERN CWA TO REMAIN MOSTLY CLOUDY...WHILE THE EASTERN THIRD OF THE U.P. WILL EXPERIENCE LINGERING MID CLOUDS IN THE MORNING...TRANSITIONING TO DIURNAL CU IN THE AFTERNOON. CONTINUED TO SHOW SLIGHT CHANCE POPS MOVING INTO WESTERN LAKE SUPERIOR AND FAR WESTERN UPPER MICHIGAN TOMORROW AFTERNOON...AHEAD OF THE SURFACE TROUGH MOVING INTO NORTHERN MINNESOTA AND THE NORTHERN EDGE OF A SHORTWAVE MOVING THROUGH SOUTHERN MINNESOTA AND NORTHERN IOWA. THINK MOST OF THE PRECIPITATION WILL STAY OFF TO THE WEST FOR TOMORROW. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 506 AM EDT SAT AUG 8 2015 DURING THE LONG TERM...MID LEVEL LOW CURRENTLY OVER SRN MANITOBA IS FCST TO MOVE SLOWLY E INTO NRN ONTARIO BY SUN MORNING. AS THIS FEATURE CONTINUES TO SHIFT SLOWLY E...A BUILDING RIDGE TO THE LEE OF THE ROCKIES WILL FORCE A DEEPENING TROF INTO ERN NAMERICA DURING THE FIRST HALF OF NEXT WEEK. THIS TROF WILL LIKELY LINGER THRU THE REST OF THE WEEK. PRIOR TO THE DEEPENING TROF...A SERIES OF SHORTWAVES TRACKING ACROSS THE PLAINS TO THE GREAT LAKES WILL PROVIDE SOME OPPORTUNITY FOR SHRA/TSTMS. DEEPENING ERN TROF AND RESULTING NW FLOW INTO THE GREAT LAKES DURING THE FIRST HALF OF NEXT WEEK WILL THEN BRING DRY WEATHER. HOWEVER...TYPICAL FOR SUMMERTIME NW FLOW...ANY SUBTLE SHORTWAVE DROPPING THRU THE AREA COULD SPARK ISOLD AFTN CONVECTION. PCPN CHANCES WILL RETURN LATE IN THE WEEK AS THERE ARE INDICATIONS OF A DECENT SHORTWAVE ROUNDING THE WRN PLAINS RIDGE AND THEN DROPPING INTO THE ERN TROF. THIS WOULD RESULT IN POSSIBLE CONVECTION WITH LOW-LEVEL JET/WAA REGIME AHEAD OF WAVE AND ALSO WITH COLD FRONT THAT WOULD DROP S INTO THE GREAT LAKES. AS FOR TEMPS... AFTER READINGS NOT TOO FAR FROM NORMAL (ON THE WARM SIDE OF NORMAL FOR MOST LOCATIONS)...DEVELOPING NW FLOW EARLY NEXT WEEK WILL DROP TEMPS TO BLO NORMAL...BUT NOT SIGNIFICANTLY AS THERE WON`T BE A TAP OF CHILLY AIR FROM NORTHERN CANADA. ABOVE NORMAL TEMPS WILL RETURN BY THU AHEAD OF THE AFOREMENTIONED SHORTWAVE ROUNDING THE RIDGE. SOME COOLING SHOULD THEN FOLLOW BY THE WEEKEND...DEPENDING ON HOW SHARPLY THE SHORTWAVE DROPS INTO THE ERN TROF. BEGINNING SUN/SUN NIGHT...MID LEVEL LOW CURRENTLY OVER SRN MANITOBA WILL HAVE OPENED UP AND WILL BE DRIFTING ACROSS NRN ONTARIO. TO THE S OF THIS FEATURE...THERE REMAINS UNCERTAINTY IN THE WEAKER SHORTWAVE ENERGY TRACKING ACROSS THE PLAINS TO THE GREAT LAKES... PARTICULARLY WITH RESPECT TO WHERE CONVECTION WILL BE FIRING WITH THESE MORE SUBTLE FEATURES. HOWEVER...THERE HAS BEEN A FAIRLY CONSISTENT SIGNAL IN THE MODELS FOR A SUBTLE SFC WAVE AND MORE SUBSTANTIAL CONVECTIVE ACTIVITY TRACKING EASTWARD FROM VCNTY OF IA EARLY SUN ON THE NRN EDGE OF STRONG INSTABILITY IN THAT AREA. THIS WILL HELP KEEP STRONG INSTABILITY FROM BUILDING N ALONG COLD FRONT THAT WILL BE MOVING INTO THE UPPER LAKES SUN/SUN NIGHT IN ASSOCIATION WITH THE NRN ONTARIO SHORTWAVE. AHEAD OF APPROACHING COLD FRONT...NAM/GFS SHOW MLCAPE INCREASING TO ROUGHLY 500 TO 1500J/KG OVER THE W HALF OF UPPER MI SUN (NAM AS HIGH AS 2000J/KG). WHILE THERE MAY BE A FEW SHRA IN THE MORNING...APPROACHING COLD FRONT AND WEAK DEEP LAYER QVECTOR CONVERGENCE SHOULD SPARK SCT CONVECTION IN THE AFTN WHICH WILL THEN SPREAD E INTO SUN NIGHT ALONG/AHEAD OF PASSING COLD FRONT. WITH DEEP LAYER SHEAR NO GREATER THAN AROUND 25KT...NOT ANTICIPATING ANY SVR STORMS. HOWEVER...IF INSTABILITY ENDS UP AT OR ABOVE THE HIGH END OF THE CURRENTLY EXPECTED RANGE...COULDN`T RULE OUT A BRIEF ISOLD SVR STORM. LATEST SPC OUTLOOKS DO NOT HIGHLIGHT UPPER MI FOR A SVR RISK SUN/SUN NIGHT...AND THAT LOOKS RIGHT ON TRACK. ON MON...COLD FRONT SHOULD BE JUST E OF THE FCST AREA AT 12Z... ENDING THE RISK OF MORE ORGANIZED PCPN. THE NAM STILL MANAGES TO BUILD MLCAPE UPWARDS OF 1500J/KG OVER THE SCNTRL AND E...BUT THE GFS SHOWS LESS THAN 50J/KG. SINCE OTHER MODELS SUPPORT THE GFS WITH A STRONGER PRES GRADIENT BTWN HIGH PRES BUILDING INTO THE NRN PLAINS AND LOW PRES/COLD FRONT TO THE E...WILL FAVOR THE THE DRIER/LACK OF INSTABILITY GFS SOLUTION. WILL LINGER SCHC POPS FOR SHRA OVER THE E EARLY. OTHERWISE...PLAN TO CARRY A DRY FCST ON MON. EXPECT HIGHS IN THE 70S...BUT IT WILL BE COOLER NEAR LAKE SUPERIOR...ESPECIALLY OVER THE E UNDER NNW WINDS THERE. MON NIGHT THRU WED...BUILDING UPPER RIDGE WITH AXIS ROUGHLY OVER THE WRN HIGH PLAINS WILL FORCE A DEEPENING ERN NAMERICA TROF AND NW FLOW OVER THE GREAT LAKES...RESULTING IN COOLER WEATHER...BUT ONLY A LITTLE BLO NORMAL FOR EARLY/MID AUG. IN THE INTERIOR...NIGHTTIME MIN TEMPS WILL PROBABLY BE IN THE 40S IN THE USUAL COOL SPOTS. THERE CONTINUES TO BE SOME INDICATION OF A WEAK SHORTWAVE DROPPING THRU THE UPPER LAKES ON TUE WHICH COULD GENERATE A FEW ISOLD SHRA WITH DAYTIME HEATING. AT THIS POINT...THE POTENTIAL IS STILL LOW ENOUGH TO PRECLUDE A MENTION OF PCPN IN THE FCST FOR TUE. WITH UPPER TROF SHIFTING A BIT FARTHER E ON WED AND SFC HIGH PRES MORE FIRMLY OVER THE AREA...DRY WEATHER IS EXPECTED TO CONTINUE. MAX TEMPS WILL BE A LITTLE HIGHER ON WED. THU/FRI...TRENDS IN MEDIUM RANGE GUIDANCE ARE FOR A STRONGER SHORTWAVE TO CUT THRU THE NRN PORTION OF THE WRN RIDGE AND THEN DROP MORE SHARPLY TO THE SE INTO THE ERN NAMERICA TROF LATE NEXT WEEK. IF THIS TREND CONTINUES WITH THE NEXT SET OF MEDIUM RANGE GUIDANCE... THEN SHRA/TSTM CHANCES WILL NEED TO BE INCREASED FOR THU...WITH PCPN POSSIBLE AS EARLY AS WED DEPENDING ON WHERE WAA IS FOCUSED AHEAD OF THE SHORTWAVE. THE 00Z ECWMF/GFS INDICATE COLD FRONT WILL BE S OF THE AREA BY FRI...LEADING TO A DRY DAY AND SOME COOLING. WILL WAIT TO SEE IF THESE TRENDS FOR THU/FRI HOLD UP IN THE NEXT ROUND OF GUIDANCE BEFORE SHIFTING FCST MORE STRONGLY TOWARD THIS SOLUTION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY MORNING) ISSUED AT 1210 AM EDT SAT AUG 8 2015 A LOW CENTERED IN SOUTHERN WISCONSIN WILL MOVE SLOWLY EAST THIS MORNING ALLOWING ISOLATED SHOWERS TO SLOWLY DISSIPATE. LINGERING LOW- LEVEL MOISTURE WILL ALLOW FOR LIFR TO POSSIBLY VLIFR CONDITIONS TO PERSIST AT ALL TAF SITES OVERNIGHT IN A LIGHT E-SE WIND FLOW. DRIER AIR SHOULD GRADUALLY MOVE INTO THE AREA LATER THIS MORNING INTO THE AFTERNOON BRINGING AN IMPROVEMENT TO CEILINGS AND VISIBILITIES WITH VFR CONDITIONS EXPECTED BY AFTERNOON. A FRONTAL SYSTEM APPROACHING FROM THE WEST TOWARD EVENING COULD BRING A CHANCE FOR SHOWERS LATE IN THE TAF PERIOD AT BOTH KIWD AND KCMX. MEANWHILE...KSAW COULD SEE A REDEVELOPMENT OF STRATUS AND MVFR CIGS BY LATE EVENING IN A CONTINUED UPSLOPE SSE FLOW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 442 AM EDT SAT AUG 8 2015 WILL CONTINUE TO TRACK BOAT OBSERVATIONS THIS MORNING TO GET A BETTER HANDLE ON ANY FOG THAT MAY BET SET UP ACROSS LAKE SUPERIOR. HOWEVER AT THIS TIME...IT LOOKS LIKE PATCHY TO AREAS OF FOG WILL BE ABOUT THE EXTENT OF IT THIS MORNING...BEFORE DISSIPATING THIS AFTERNOON. EXPECT A WEAKENING LOW OVER E WI/S LAKE MI THIS MORNING. A SECONDARY LOW LAKE WINNIPEG WILL SLOWLY MOVE E OVER THE NEXT FEW DAYS AND REACH S JAMES BAY BY MONDAY. THAT LOW WILL SWEEP A TROUGH ACROSS THE UPPER GREAT LAKES REGION ON SUNDAY. A HIGH PRESSURE RIDGE STRETCHING FROM MANITOBA TO THE N PLAINS MONDAY WILL SLIDE OVER THE GREAT LAKES TUESDAY AND WEDNESDAY. EXPECT WIND GUSTS LESS THAN 25KTS THROUGH THE PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...ROLFSON AVIATION...VOSS MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
442 AM EDT SAT AUG 8 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 254 PM EDT FRI AUG 7 2015 A SHORTWAVE HAS UNDERCUT THE UPPER RIDGE OVER THE UPPER MISSISSIPPI VALLEY AND IS NOW DIVING SOUTHEAST ACROSS EASTERN WISCONSIN. THAT WAVE IS SUPPORTING THE SHOWERS AND A FEW EMBEDDED THUNDERSTORMS MOVING ACROSS THAT AREA. FARTHER TO THE WEST...A 1008MB SURFACE LOW IS LOCATED NEAR EAU CLAIRE WISCONSIN. TO THE NORTHEAST OF THE SURFACE LOW...AN AREA OF SHOWERS ARE MOVING EAST ACROSS UPPER MICHIGAN AT THIS TIME...TIED TO THE NORTHERN EDGE OF THE 850-700MB Q- VECTOR CONVERGENCE AND BROAD WARM AIR ADVECTION. THE HEAVIEST RAIN SO FAR TODAY HAS FALLEN OVER THE WESTERN HALF OF THE U.P....WITH 0.5 TO 0.65 INCHES OF RAIN FALLING OVER THE BARAGA PLAINS TODAY. AMOUNTS DIMINISH TO A TENTH OF AN INCH THROUGH 2PM FROM NEGAUNEE SOUTH TO IRON MOUNTAIN AND EVEN LESS FARTHER TO THE EAST. THE SURFACE LOW AND SHORTWAVE WILL SLOWLY DISSIPATE AS THEY MOVE TO THE EAST-SOUTHEAST TONIGHT...LIMITING THE INFLUENCE OF BOTH FEATURES THROUGH THE NIGHT. EXPECT THE SHOWERS TO DIMINISH AND DRIFT TO THE SOUTHEAST THROUGH THE EVENING (TIED TO THE 850-700MB Q-VECTOR CONVERGENCE)...AND LARGELY BE OUT OF THE CWA AROUND 06Z. BUT WITH THE MODELS CONTINUING TO SHOW LOW LEVEL MOISTURE PIVOTING TO THE NORTHWEST ON THE NORTHEAST SIDE OF THE 925-850 TROUGH IN CENTRAL/NORTHERN WISCONSIN...EXPECT ABUNDANT LOW CLOUDS TO BE IN PLACE ACROSS THE AREA. THESE LOW CLOUDS CAN ALREADY BE SEEN OVER EASTERN MINNESOTA AND WESTERN WISCONSIN...AND THEY HAVE BEEN WORKING INTO WESTERN UPPER MICHIGAN THROUGH THE DAY. THINK DRYING AND INCREASING SUBSIDENCE ABOVE THAT...GENERALLY ABOVE 750MB OVER THE WEST...WILL ALSO HELP THE DIMINISHMENT OF THE WIDESPREAD SHOWERS. DID HOLD ONTO THE SHOWERS A LITTLE LONGER OVER THE HIGHER TERRAIN UPSLOPE AREAS IN CENTRAL UPPER MICHIGAN DUE TO THE FAVORABLY SOUTHEASTERLY FLOW...BUT THE PRECIPITATION MAY FALL MORE AS DRIZZLE THAN RAIN. IN ADDITION...HAVE TRENDED FOG UP TO AREAS TO WIDESPREAD VALUES OVER THE WEST/CENTRAL U.P. WHERE THE BETTER RAIN HAS FALLEN AND TIED TO THE LOWEST 5KFT BEING SATURATED ON THE NAM/GFS SOUNDINGS. ONE ITEM TO WATCH...THE LATEST RAP RUNS HAVE BEEN HOLDING ONTO DRIER NEAR SURFACE AIR OVER THE NORTH CENTRAL...WHICH WOULD GREATLY REDUCE THE POTENTIAL FOR LOW CLOUDS AND FOG. EXPECT THE LOW LEVEL MOISTURE TO HOLD ON THROUGH THE FIRST HALF OF SATURDAY OVER THE WESTERN HALF TO TWO-THIRDS OF THE U.P. BEFORE THE CONTINUED SUBSIDENCE AND INFLUX OF DRIER AIR TRIES TO BREAK OF THE CLOUDS. WHILE THAT SHOULD RAISE THE CEILINGS ACROSS THE AREA...STILL EXPECT THE WESTERN CWA TO REMAIN MOSTLY CLOUDY...WHILE THE EASTERN THIRD OF THE U.P. WILL EXPERIENCE LINGERING MID CLOUDS IN THE MORNING...TRANSITIONING TO DIURNAL CU IN THE AFTERNOON. CONTINUED TO SHOW SLIGHT CHANCE POPS MOVING INTO WESTERN LAKE SUPERIOR AND FAR WESTERN UPPER MICHIGAN TOMORROW AFTERNOON...AHEAD OF THE SURFACE TROUGH MOVING INTO NORTHERN MINNESOTA AND THE NORTHERN EDGE OF A SHORTWAVE MOVING THROUGH SOUTHERN MINNESOTA AND NORTHERN IOWA. THINK MOST OF THE PRECIPITATION WILL STAY OFF TO THE WEST FOR TOMORROW. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 314 PM EDT FRI AUG 7 2015 FCST FOCUS IN THE MEDIUM RANGE PERIOD WL BE ON POPS THE SECOND HALF OF THIS WEEKEND ASSOCIATED WITH STRONG DISTUBANCE OVER SCENTRAL CANADA THAT WL BE DROPPING SLOWLY ESEWD THRU NW ONTARIO AND DRAGGING A COLD FNT ACRS UPR MI ON SUN NGT. TEMPS AHEAD OF THE COLD FROPA WL BE AOA NORMAL. DURING THE FIRST HALF OF THE NEXT WEEK...EXPECT TEMPS TO FALL BLO NORMAL WITH NW FLOW ALOFT DEVELOPING BTWN A BLDG UPR RDG IN THE PLAINS AND DEEPENING TROF DOWNSTREAM IN ERN NAMERICA. CNDN HI PRES UNDER THIS NW FLOW ALOFT WL BRING GENERALLY DRY WX DURING THE MON THRU WED PERIOD. LOOKS LIKE TEMPS WL REBOUND AOA NORMAL LATER IN THE WEEK AS PLAINS RDG BLDS TOWARD THE WRN LKS. SAT NGT THRU SUN NGT...STRONG SHRTWV OVER FAR NW ONTARIO THAT WL BE TOPPING UPR RDG IN THE PLAINS IS FCST TO SLIDE SLOWLY ESE THRU NRN ONTARIO. ALTHOUGH THERE ARE STILL SOME TIMING DIFFERENCES...MOST OF THE LATEST GUIDANCE INDICATE A FASTER PRIMARY COLD FROPA ON SUN NGT. SINCE THE SHARPER DYNAMIC FORCING ASSOCIATED WITH THE ONTARIO SHRTWV WL REMAIN TO THE N OF UPR MI...POPS/PCPN AMOUNTS AS EARLY AS SAT NGT IN ADVANCE OF THIS COLD FNT WL DEPEND ON THE DEGREE TO WHICH MSTR INFLOW INTO THE UPR LKS WL BE DISRUPTED BY A W-E ORIENTED BNDRY STRETCHING FM IOWA INTO THE LOWER LKS AND CONVECTION THAT FIRES ALONG THIS AXIS ACCOMPANYING THE PASSAGE OF ANOTHER SHRTWV OVER THAT AREA. THE 12Z NAM IS MOST EXTREME SHOWING A NEAR ABSENCE OF PCPN ACRS THE CWA DURING THIS ENTIRE PERIOD WITH A LACK OF ANY MSTR INFLOW/DYNAMIC FORCING TO THE N OF STRONG TS COMPLEX/DEEPER SFC LO TRACKING ALONG THE BNDRY. THE OTHER MODELS SHOW A MORE PRONOUNCED AXIS OF HIER H85 THETA E AND THUS MORE DEEP LYR MSTR CNVGC/FORCING/ QPF. BEST CHC FOR SOMWHAT HIER POPS WL BE OVER THE W ON SAT EVNG AND THEN THE CENTRAL ON SUN AFTN/EVNG...WHEN THE 12Z GFS SHOWS MUCAPE AS HI AS 2500 J/KG...DURING PERIODS OF DAYTIME HEATING. BUT GIVEN MODEL/TIMING UNCERTAINTIES AND SUPPORT FOR LARGER SCALE FORCING TO PASS TO THE N AND S OF THE CWA...FCST WL POPS WL BE NO HIER THAN THE CHC CATEGORY. MON...SINCE RECENT MEDIUM RANGE GUIDANCE HAS TRENDED TO SPEED UP PASSAGE OF COLD FROPA ATTENDANT TO SHRTWV SHIFTING ESEWD THRU NW ONTARIO AND ARRIVAL OF DEEP LYR QVECTOR DVGC/LARGER SCALE SUBSIDENCE/MID LVL DRYING...PCPN CHCS FOR MON LOOK TO BE DIMINISHING. WITH MORE SUNSHINE...H85 TEMPS FCST IN IN THE 10 TO 12C RANGE WL SUPPORT MAX TEMPS IN THE 70S. LOCATIONS NEAR LK SUP WL BE COOLEST WITH LLVL NNW FLOW IN ADVANCE OF APRCHG CNDN HI PRES. MON NGT THRU WED...THE UPR RDG IN THE PLAINS IS FCST TO AMPLIFY EARLY IN THE WEEK...ALLOWING THE TROF IN ERN NAMERICA TO DEEPEN AND A MORE PRONOUNCED NW FLOW ALOFT BTWN THESE FEATURES TO PREVAIL OVER THE GREAT LKS. THE ARRIVAL OF CNDN HI PRES/H85 TEMPS AS LO AS 8 TO 10C WL RESULT IN GENERALLY DRY AND COOLER WX FOR MON NGT INTO WED. ALTHOUGH SOME OF THE MODELS INDICATE A SHRTWV EMBEDDED IN THE NW FLOW ALOFT COULD CAUSE SOME SHOWERS DURING DAYTIME HEATING ON TUE... THE COVERAGE/INTENSITY OF THESE SHOWERS WL BE LIMITED BY THE ABSENCE OF ANY DEEPER MSTR AND GENERAL LARGER SCALE SUBSIDENCE UNDER THE CONFLUENT NW FLOW ALOFT. RETAINED GOING DRY FCST FOR NOW. WITH PLENTY OF SUNSHINE...WED AFTN WL TURN WARMER AS H85 TEMPS REBOUND TOWARD 15C OVER THE W AS THE PLAINS RDG SHIFTS TOWARD THE WRN LKS. LATE WEEK...A NUMBER OF THE EXTENDED MODELS SHOW ANOTHER SHRTWV ROUNDING THE TOP OF THE PLAINS RDG WL INFLUENCE THE AREA ON THU AND BRING THE THREAT OF SOME SHOWERS/TS. AS THE UPR RDG TO THE W BUILDS BACK TOWARD THE UPR LKS IN THE WAKE OF THIS SHRTWV PASSAGE...FRI SHOULD BE DRY AND WARMER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY MORNING) ISSUED AT 1210 AM EDT SAT AUG 8 2015 A LOW CENTERED IN SOUTHERN WISCONSIN WILL MOVE SLOWLY EAST THIS MORNING ALLOWING ISOLATED SHOWERS TO SLOWLY DISSIPATE. LINGERING LOW- LEVEL MOISTURE WILL ALLOW FOR LIFR TO POSSIBLY VLIFR CONDITIONS TO PERSIST AT ALL TAF SITES OVERNIGHT IN A LIGHT E-SE WIND FLOW. DRIER AIR SHOULD GRADUALLY MOVE INTO THE AREA LATER THIS MORNING INTO THE AFTERNOON BRINGING AN IMPROVEMENT TO CEILINGS AND VISIBILITIES WITH VFR CONDITIONS EXPECTED BY AFTERNOON. A FRONTAL SYSTEM APPROACHING FROM THE WEST TOWARD EVENING COULD BRING A CHANCE FOR SHOWERS LATE IN THE TAF PERIOD AT BOTH KIWD AND KCMX. MEANWHILE...KSAW COULD SEE A REDEVELOPMENT OF STRATUS AND MVFR CIGS BY LATE EVENING IN A CONTINUED UPSLOPE SSE FLOW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 442 AM EDT SAT AUG 8 2015 WILL CONTINUE TO TRACK BOAT OBSERVATIONS THIS MORNING TO GET A BETTER HANDLE ON ANY FOG THAT MAY BET SET UP ACROSS LAKE SUPERIOR. HOWEVER AT THIS TIME...IT LOOKS LIKE PATCHY TO AREAS OF FOG WILL BE ABOUT THE EXTENT OF IT THIS MORNING...BEFORE DISSIPATING THIS AFTERNOON. EXPECT A WEAKENING LOW OVER E WI/S LAKE MI THIS MORNING. A SECONDARY LOW LAKE WINNIPEG WILL SLOWLY MOVE E OVER THE NEXT FEW DAYS AND REACH S JAMES BAY BY MONDAY. THAT LOW WILL SWEEP A TROUGH ACROSS THE UPPER GREAT LAKES REGION ON SUNDAY. A HIGH PRESSURE RIDGE STRETCHING FROM MANITOBA TO THE N PLAINS MONDAY WILL SLIDE OVER THE GREAT LAKES TUESDAY AND WEDNESDAY. EXPECT WIND GUSTS LESS THAN 25KTS THROUGH THE PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KC AVIATION...VOSS MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
124 AM EDT SAT AUG 8 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 330 PM EDT FRI AUG 7 2015 A WEAK AREA OF LOW PRESSURE WILL MOVE INTO THE AREA TONIGHT AND BRING SCATTERED SHOWERS. MOST OF THESE SHOWERS SHOULD EXIT THE AREA LATE TONIGHT...GIVING THE REGION A NICE SATURDAY. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL ARRIVE SUNDAY AFTERNOON AND LINGER INTO THE EVENING. THIS WILL BE A MORE WIDESPREAD RAIN...AND THERE MAY BE A FEW STRONG STORMS TOO. TEMPERATURES THROUGH THE WEEKEND WILL BE MILD WITH DAYTIME HIGHS MAINLY IN THE UPPER 70S TO AROUND 80. A FEW SHOWERS MAY LINGER INTO MONDAY...BUT THEN WE SHOULD SEE A DRY PERIOD FROM MONDAY NIGHT THROUGH THURSDAY. ANOTHER CHANCE OF RAIN WILL MOVE IN FOR THURSDAY NIGHT AND FRIDAY. HIGHS EACH DAY SHOULD REMAIN IN THE UPPER 70 TO MID 80S. && .UPDATE... ISSUED AT 928 PM EDT FRI AUG 7 2015 THE SHORTWAVE CURRENTLY MOVING ACROSS LOWER MICHIGAN CONTINUES TO PRODUCE MODERATE RAIN OVER OUR NORTHERN COUNTIES. SEVERAL MESONET SITES HAVE HAD BETWEEN .35 AND .50 INCHES OF RAIN OVER WESTERN MASON COUNTY SO FAR THIS EVENING. AS A RESULT I HAVE INCREASED THE POP TO NEAR 100% OVER OUR NORTHERN COUNTIES THROUGH AT LEAST MIDNIGHT AND I ALSO INCREASED QPF TO NEAR HALF INCH OVER THE NW SECTIONS OF OUR FORECAST AREA TONIGHT. SOUTHERN AREAS...DUE TO THE DRY EASTERLY LOW LEVEL INFLOW TO THE SYSTEM...WILL ONLY SEE SPRINKLES OR POSSIBLY AND A FEW HUNDERTHS OF AN INCH OF RAIN IN ISOLATED LOCATIONS. FOR THE MOST PART AREAS NEAR AND SOUTH OF INTERSTATE 96 WILL NOT SEE MUCH IN THE WAY OF MEASURABLE RAIN TONIGHT. THIS SYSTEM WILL SLOWLY CONTINUE TO WEAKEN AS IT MOVES ACROSS THE AREA SO THE RAINFALL RATES WILL DECREASE OVER OUR NORTHERN COUNTIES BY MIDNIGHT. EVEN SO THERE IS A TRAILING UPPER WAVE THAT WILL COME ACROSS SOUTHWEST LOWER MICHIGAN JUST PRIOR TO SUNRISE. THIS WILL RESULT IN ADDITIONAL SHOWERS ACROSS THE AREA. THE LATEST RAP MODEL AND ASSOCIATED MODEL SOUNDINGS DO NOT SHOW ENOUGH INSTABILITY FOR THUNDERSTORMS SO I EXPUNGED THE MENTION OF THUNDERSTORMS FROM OUR OVERNIGHT FORECAST. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 330 PM EDT FRI AUG 7 2015 A GOOD CHANCE OF RAIN TONIGHT...ESPECIALLY EARLY ON. THEN ANOTHER STRONG CHANCE OF RAIN COMES SUNDAY AFTERNOON INTO THE EVENING. TOPS WERE SLOWLY WARMING WITH THE SYSTEM THAT WAS MOVING ACROSS LAKE MICHIGAN THIS AFTERNOON. HOWEVER...AS MENTIONED IN AN EARLIER UPDATE...THE LOW LEVEL JET FUELING THESE SHOWERS WILL HOLD TOGETHER THROUGH THIS EVENING...BUT THEN SLOWLY WEAKEN AND MOVE INTO NORTHERN LOWER LATER TONIGHT. WILL INCREASE POPS TO LIKELY OVER CENTRAL LOWER...WHILE KEEPING CHANCE POPS ELSEWHERE. SOME WEAK INSTABILITY ARRIVES LATE TONIGHT WITH THE HIGHER DEW POINTS...SO INCLUDED THE MENTION OF ISOLATED THUNDER. OTHER THAN SOME LINGERING MORNING SHOWERS ACROSS THE NE CWA SATURDAY MORNING...THE REST OF THE CWA SHOULD BE DRY ON SATURDAY AS WE WILL BE IN BETWEEN SYSTEMS. LOW CLOUDS WILL BE COMMONPLACE FIRST THING...BUT THESE SHOULD BREAK UP THROUGH THE DAY FOR PARTLY SUNNY SKIES IN THE AFTERNOON. THE MODELS ARE IN BETTER AGREEMENT SHOWING LOW PRESSURE EJECTING OUT OF THE CENTRAL PLAINS ON SATURDAY AND TRACKING IT ACROSS THE LOWER GREAT LAKES SUNDAY NIGHT. THE SYSTEM CONTINUES TO LOOK MORE IMPRESSIVE WITH GOOD JET DYNAMICS MOVING ACROSS SW MI STARTING LATE SATURDAY NIGHT AND CONTINUING INTO SUNDAY EVENING. AGREE WITH SPC INCLUDING PORTIONS OF THE CWA IN THE MARGINAL RISK OF SEVERE. HOWEVER SINCE WE WILL BE ON THE COOL SIDE OF THE SYSTEM MOST OF THE INSTABILITY WILL BE ELEVATED. THIS LEAVES LARGE HAIL AS THE MAIN SEVERE THREAT. INSTABILITY SHOULD NOT BE OFF THE CHARTS...SO ANY SEVERE THREAT SHOULD BE LOW END. SEVERE TIME FRAME SHOULD SHOULD BE LATE AFTERNOON/EARLY EVENING SUNDAY. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 330 PM EDT FRI AUG 7 2015 NO SIGNIFICANT CHANGE WITH A COLD FRONT EXPECTED TO BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ON MONDAY...AND THEN DRY AND SEASONABLY COOL THROUGH NEXT WEEK. LOOKING FURTHER...SEASONABLY WARM CONDITIONS RETURN TOWARDS NEXT WEEKEND WITH CONTINUED DRY CONDITIONS THROUGH WEEK TWO. MONDAYS FRONTAL PASSAGE SHOULD BE SUPPORTED BY ROUGHLY 500 J/KG OF CAPE AND 0-6KM SHEAR OF 30KTS WHICH WOULD BE ENOUGH FOR A FEW ISOLATED STRONG STORMS. HOWEVER...THE FORCING IS NOT OVERLY IMPRESSIVE OR ORGANIZED BUT...THEN AGAIN...LATEST NWP IS TRENDING STRONGER...SO POPS ARE UP A BIT TODAY. REST OF THE WEEK LOOKS A LOT LIKE THIS WEEK WITH HIGH PRESSURE AND LIKELY SOME DIURNAL FAIR WEATHER CLOUDINESS THROUGHOUT THE WEEK. UPPER PATTERN CONTINUES TO FEATURE RIDGE OVER CENTRAL WEST WITH CLOSED HIGH OVER WEST TEXAS AND A DOWNSTREAM TROUGH OVER THE EAST. THE PATTERN AMPLIFIES A BIT EARLY NEXT WEEK LEADING TO THE COOLER AND DRIER AIR OVER MICHIGAN FOR MIDWEEK AND THEN FLATTENS WITH WARMER AND LIKELY A BIT MORE HUMID AIR FOR NEXT WEEKEND. LOOKING FURTHER OUT THE PATTERN APPEARS TO MORE OR LESS REPEAT IN WEEK TWO. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 123 AM EDT SAT AUG 8 2015 LIGHT RAIN SHOWERS CONTINUE TO MOVE ACROSS CENTRAL LOWER MI. A FEW SHOWERS MAY CLIP THE NRN TAF SITES OVERNIGHT BUT NO RESTRICTIONS TO VSBY. VFR EXPECTED THROUGH THE PERIOD. && .MARINE... ISSUED AT 330 PM EDT FRI AUG 7 2015 WINDS AND WAVES WILL STAY UNDER 3 FEET THROUGH THE SHORT TERM. THUNDERSTORMS WILL BE THE MAIN THREAT...COMING IN LATE SATURDAY NIGHT AND LINGERING THROUGH SUNDAY EVENING. && .HYDROLOGY... ISSUED AT 1241 PM EDT FRI AUG 7 2015 NO FLOODING ISSUES EXPECTED FOR THE NEXT WEEK OR MORE AS A RELATIVELY DRY PATTERN REMAINS IN PLACE. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...JK SHORT TERM...JK LONG TERM...COBB AVIATION...04 HYDROLOGY...MACZKO MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1210 AM EDT SAT AUG 8 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 254 PM EDT FRI AUG 7 2015 A SHORTWAVE HAS UNDERCUT THE UPPER RIDGE OVER THE UPPER MISSISSIPPI VALLEY AND IS NOW DIVING SOUTHEAST ACROSS EASTERN WISCONSIN. THAT WAVE IS SUPPORTING THE SHOWERS AND A FEW EMBEDDED THUNDERSTORMS MOVING ACROSS THAT AREA. FARTHER TO THE WEST...A 1008MB SURFACE LOW IS LOCATED NEAR EAU CLAIRE WISCONSIN. TO THE NORTHEAST OF THE SURFACE LOW...AN AREA OF SHOWERS ARE MOVING EAST ACROSS UPPER MICHIGAN AT THIS TIME...TIED TO THE NORTHERN EDGE OF THE 850-700MB Q- VECTOR CONVERGENCE AND BROAD WARM AIR ADVECTION. THE HEAVIEST RAIN SO FAR TODAY HAS FALLEN OVER THE WESTERN HALF OF THE U.P....WITH 0.5 TO 0.65 INCHES OF RAIN FALLING OVER THE BARAGA PLAINS TODAY. AMOUNTS DIMINISH TO A TENTH OF AN INCH THROUGH 2PM FROM NEGAUNEE SOUTH TO IRON MOUNTAIN AND EVEN LESS FARTHER TO THE EAST. THE SURFACE LOW AND SHORTWAVE WILL SLOWLY DISSIPATE AS THEY MOVE TO THE EAST-SOUTHEAST TONIGHT...LIMITING THE INFLUENCE OF BOTH FEATURES THROUGH THE NIGHT. EXPECT THE SHOWERS TO DIMINISH AND DRIFT TO THE SOUTHEAST THROUGH THE EVENING (TIED TO THE 850-700MB Q-VECTOR CONVERGENCE)...AND LARGELY BE OUT OF THE CWA AROUND 06Z. BUT WITH THE MODELS CONTINUING TO SHOW LOW LEVEL MOISTURE PIVOTING TO THE NORTHWEST ON THE NORTHEAST SIDE OF THE 925-850 TROUGH IN CENTRAL/NORTHERN WISCONSIN...EXPECT ABUNDANT LOW CLOUDS TO BE IN PLACE ACROSS THE AREA. THESE LOW CLOUDS CAN ALREADY BE SEEN OVER EASTERN MINNESOTA AND WESTERN WISCONSIN...AND THEY HAVE BEEN WORKING INTO WESTERN UPPER MICHIGAN THROUGH THE DAY. THINK DRYING AND INCREASING SUBSIDENCE ABOVE THAT...GENERALLY ABOVE 750MB OVER THE WEST...WILL ALSO HELP THE DIMINISHMENT OF THE WIDESPREAD SHOWERS. DID HOLD ONTO THE SHOWERS A LITTLE LONGER OVER THE HIGHER TERRAIN UPSLOPE AREAS IN CENTRAL UPPER MICHIGAN DUE TO THE FAVORABLY SOUTHEASTERLY FLOW...BUT THE PRECIPITATION MAY FALL MORE AS DRIZZLE THAN RAIN. IN ADDITION...HAVE TRENDED FOG UP TO AREAS TO WIDESPREAD VALUES OVER THE WEST/CENTRAL U.P. WHERE THE BETTER RAIN HAS FALLEN AND TIED TO THE LOWEST 5KFT BEING SATURATED ON THE NAM/GFS SOUNDINGS. ONE ITEM TO WATCH...THE LATEST RAP RUNS HAVE BEEN HOLDING ONTO DRIER NEAR SURFACE AIR OVER THE NORTH CENTRAL...WHICH WOULD GREATLY REDUCE THE POTENTIAL FOR LOW CLOUDS AND FOG. EXPECT THE LOW LEVEL MOISTURE TO HOLD ON THROUGH THE FIRST HALF OF SATURDAY OVER THE WESTERN HALF TO TWO-THIRDS OF THE U.P. BEFORE THE CONTINUED SUBSIDENCE AND INFLUX OF DRIER AIR TRIES TO BREAK OF THE CLOUDS. WHILE THAT SHOULD RAISE THE CEILINGS ACROSS THE AREA...STILL EXPECT THE WESTERN CWA TO REMAIN MOSTLY CLOUDY...WHILE THE EASTERN THIRD OF THE U.P. WILL EXPERIENCE LINGERING MID CLOUDS IN THE MORNING...TRANSITIONING TO DIURNAL CU IN THE AFTERNOON. CONTINUED TO SHOW SLIGHT CHANCE POPS MOVING INTO WESTERN LAKE SUPERIOR AND FAR WESTERN UPPER MICHIGAN TOMORROW AFTERNOON...AHEAD OF THE SURFACE TROUGH MOVING INTO NORTHERN MINNESOTA AND THE NORTHERN EDGE OF A SHORTWAVE MOVING THROUGH SOUTHERN MINNESOTA AND NORTHERN IOWA. THINK MOST OF THE PRECIPITATION WILL STAY OFF TO THE WEST FOR TOMORROW. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 314 PM EDT FRI AUG 7 2015 FCST FOCUS IN THE MEDIUM RANGE PERIOD WL BE ON POPS THE SECOND HALF OF THIS WEEKEND ASSOCIATED WITH STRONG DISTUBANCE OVER SCENTRAL CANADA THAT WL BE DROPPING SLOWLY ESEWD THRU NW ONTARIO AND DRAGGING A COLD FNT ACRS UPR MI ON SUN NGT. TEMPS AHEAD OF THE COLD FROPA WL BE AOA NORMAL. DURING THE FIRST HALF OF THE NEXT WEEK...EXPECT TEMPS TO FALL BLO NORMAL WITH NW FLOW ALOFT DEVELOPING BTWN A BLDG UPR RDG IN THE PLAINS AND DEEPENING TROF DOWNSTREAM IN ERN NAMERICA. CNDN HI PRES UNDER THIS NW FLOW ALOFT WL BRING GENERALLY DRY WX DURING THE MON THRU WED PERIOD. LOOKS LIKE TEMPS WL REBOUND AOA NORMAL LATER IN THE WEEK AS PLAINS RDG BLDS TOWARD THE WRN LKS. SAT NGT THRU SUN NGT...STRONG SHRTWV OVER FAR NW ONTARIO THAT WL BE TOPPING UPR RDG IN THE PLAINS IS FCST TO SLIDE SLOWLY ESE THRU NRN ONTARIO. ALTHOUGH THERE ARE STILL SOME TIMING DIFFERENCES...MOST OF THE LATEST GUIDANCE INDICATE A FASTER PRIMARY COLD FROPA ON SUN NGT. SINCE THE SHARPER DYNAMIC FORCING ASSOCIATED WITH THE ONTARIO SHRTWV WL REMAIN TO THE N OF UPR MI...POPS/PCPN AMOUNTS AS EARLY AS SAT NGT IN ADVANCE OF THIS COLD FNT WL DEPEND ON THE DEGREE TO WHICH MSTR INFLOW INTO THE UPR LKS WL BE DISRUPTED BY A W-E ORIENTED BNDRY STRETCHING FM IOWA INTO THE LOWER LKS AND CONVECTION THAT FIRES ALONG THIS AXIS ACCOMPANYING THE PASSAGE OF ANOTHER SHRTWV OVER THAT AREA. THE 12Z NAM IS MOST EXTREME SHOWING A NEAR ABSENCE OF PCPN ACRS THE CWA DURING THIS ENTIRE PERIOD WITH A LACK OF ANY MSTR INFLOW/DYNAMIC FORCING TO THE N OF STRONG TS COMPLEX/DEEPER SFC LO TRACKING ALONG THE BNDRY. THE OTHER MODELS SHOW A MORE PRONOUNCED AXIS OF HIER H85 THETA E AND THUS MORE DEEP LYR MSTR CNVGC/FORCING/ QPF. BEST CHC FOR SOMWHAT HIER POPS WL BE OVER THE W ON SAT EVNG AND THEN THE CENTRAL ON SUN AFTN/EVNG...WHEN THE 12Z GFS SHOWS MUCAPE AS HI AS 2500 J/KG...DURING PERIODS OF DAYTIME HEATING. BUT GIVEN MODEL/TIMING UNCERTAINTIES AND SUPPORT FOR LARGER SCALE FORCING TO PASS TO THE N AND S OF THE CWA...FCST WL POPS WL BE NO HIER THAN THE CHC CATEGORY. MON...SINCE RECENT MEDIUM RANGE GUIDANCE HAS TRENDED TO SPEED UP PASSAGE OF COLD FROPA ATTENDANT TO SHRTWV SHIFTING ESEWD THRU NW ONTARIO AND ARRIVAL OF DEEP LYR QVECTOR DVGC/LARGER SCALE SUBSIDENCE/MID LVL DRYING...PCPN CHCS FOR MON LOOK TO BE DIMINISHING. WITH MORE SUNSHINE...H85 TEMPS FCST IN IN THE 10 TO 12C RANGE WL SUPPORT MAX TEMPS IN THE 70S. LOCATIONS NEAR LK SUP WL BE COOLEST WITH LLVL NNW FLOW IN ADVANCE OF APRCHG CNDN HI PRES. MON NGT THRU WED...THE UPR RDG IN THE PLAINS IS FCST TO AMPLIFY EARLY IN THE WEEK...ALLOWING THE TROF IN ERN NAMERICA TO DEEPEN AND A MORE PRONOUNCED NW FLOW ALOFT BTWN THESE FEATURES TO PREVAIL OVER THE GREAT LKS. THE ARRIVAL OF CNDN HI PRES/H85 TEMPS AS LO AS 8 TO 10C WL RESULT IN GENERALLY DRY AND COOLER WX FOR MON NGT INTO WED. ALTHOUGH SOME OF THE MODELS INDICATE A SHRTWV EMBEDDED IN THE NW FLOW ALOFT COULD CAUSE SOME SHOWERS DURING DAYTIME HEATING ON TUE... THE COVERAGE/INTENSITY OF THESE SHOWERS WL BE LIMITED BY THE ABSENCE OF ANY DEEPER MSTR AND GENERAL LARGER SCALE SUBSIDENCE UNDER THE CONFLUENT NW FLOW ALOFT. RETAINED GOING DRY FCST FOR NOW. WITH PLENTY OF SUNSHINE...WED AFTN WL TURN WARMER AS H85 TEMPS REBOUND TOWARD 15C OVER THE W AS THE PLAINS RDG SHIFTS TOWARD THE WRN LKS. LATE WEEK...A NUMBER OF THE EXTENDED MODELS SHOW ANOTHER SHRTWV ROUNDING THE TOP OF THE PLAINS RDG WL INFLUENCE THE AREA ON THU AND BRING THE THREAT OF SOME SHOWERS/TS. AS THE UPR RDG TO THE W BUILDS BACK TOWARD THE UPR LKS IN THE WAKE OF THIS SHRTWV PASSAGE...FRI SHOULD BE DRY AND WARMER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY MORNING) ISSUED AT 1210 AM EDT SAT AUG 8 2015 A LOW CENTERED IN SOUTHERN WISCONSIN WILL MOVE SLOWLY EAST THIS MORNING ALLOWING ISOLATED SHOWERS TO SLOWLY DISSIPATE. LINGERING LOW- LEVEL MOISTURE WILL ALLOW FOR LIFR TO POSSIBLY VLIFR CONDITIONS TO PERSIST AT ALL TAF SITES OVERNIGHT IN A LIGHT E-SE WIND FLOW. DRIER AIR SHOULD GRADUALLY MOVE INTO THE AREA LATER THIS MORNING INTO THE AFTERNOON BRINGING AN IMPROVEMENT TO CEILINGS AND VISIBILITIES WITH VFR CONDITIONS EXPECTED BY AFTERNOON. A FRONTAL SYSTEM APPROACHING FROM THE WEST TOWARD EVENING COULD BRING A CHANCE FOR SHOWERS LATE IN THE TAF PERIOD AT BOTH KIWD AND KCMX. MEANWHILE...KSAW COULD SEE A REDEVELOPMENT OF STRATUS AND MVFR CIGS BY LATE EVENING IN A CONTINUED UPSLOPE SSE FLOW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 254 PM EDT FRI AUG 7 2015 A LOW PRESSURE SYSTEM OVER WESTERN WISCONSIN WILL DISSIPATE TONIGHT INTO SATURDAY MORNING AS IT MOVES EAST. MEANWHILE...A STRONGER LOW NEAR LAKE WINNIPEG WILL MOVE TO JAMES BAY BY MONDAY..SWEEPING A BROAD TROUGH ACROSS THE UPPER GREAT LAKES REGION. HIGH PRESSURE WILL BUILD IN BEHIND THE TROUGH...AND CONTINUE INTO THE MIDDLE OF NEXT WEEK. WITH WEAK PRESSURE GRADIENTS EXPECTED...WINDS ARE EXPECTED TO STAY BELOW 20KTS THROUGH THE PERIOD. FINALLY...WITH RAIN AND ABUNDANT LOW LEVEL MOISTURE MOVING OVER WESTERN AND CENTRAL LAKE SUPERIOR...COULD SEE SOME PATCHY FOG OVER THOSE AREAS TONIGHT INTO SATURDAY MORNING...BUT DON/T EXPECT WIDESPREAD...DENSE FOG AT THIS TIME. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KC AVIATION...VOSS MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
335 PM CDT SAT AUG 8 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 336 PM CDT SAT AUG 8 2015 THE MAIN SHORT TERM CONCERN IS THE CONVECTIVE THREAT INTO THE EVENING AND REDEVELOPING SUNDAY. WIDELY SCATTERED SHOWERS CONTINUE TO MOVE EAST ACROSS THE AREA. SOME HEATING OCCURRED TO THE WEST AND SOUTH AS CLOUDS CLEARED SOME. THE LATEST SPC MESOSCALE ANALYSIS SHOWS MLCAPE 1500-200 J/KG OVER THE MN PORTION OF THE AREA. BEST SHEAR IS LOCATED OVER NORTHEAST MN IN THE AREA WHERE A MORE CONCENTRATED AREA OF STORMS CURRENTLY RESIDES. ANY REAL SEVERE POTENTIAL WILL BE FOUND IN THIS AREA INTO THE EVENING...POSSIBLE MAKING IT INTO THE NORTHEAST PORTION OF THE CWA. WILL CONTINUE THE HIGHER CHANCE POPS IN THIS AREA...TRAILING OFF TO SLIGHT CHANCE TO THE SOUTH. UPPER TROUGH MOVING ACROSS THE NORTHERN PORTION OF THE STATE SHOULD DRIVE MAIN CONVECTIVE THREAT OVER THE NORTHEAST. ALSO...SHOULD SEE STORMS GRADUALLY WEAKEN WITH THE LOSS OF HEATING INTO THE EVENING. AT THE MOMENT...FEEL THERE WILL BE ENOUGH CLOUD COVER AROUND FROM THE FRONT TO THE NORTH AND THE MCS TO THE SOUTH TO LIMIT SIGNIFICANT FOG. HOWEVER...IF THE SKY CLEARS OUT SIGNIFICANTLY LATE TONIGHT...FOG MAY BECOME MORE OF AN ISSUE WITH LIGHT WINDS AND HIGHER DEWPOINTS AROUND. THE SURFACE FRONT DROPS INTO THE AREA SUNDAY WITH ATTENDANT CHANCE OF -TSRA MAINLY IN THE AFTERNOON. WE CURRENTLY HAVE A MARGINAL SEVERE RISK OVER THE SOUTHWEST PORTION OVER THE CWA...WHICH LOOKS BEST AT THIS TIME. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 336 PM CDT SAT AUG 8 2015 THE LONG TERM FORECAST IS BOOK-ENDED WITH SHOWER AND THUNDERSTORM CHANCES...BUT WILL BE MARKED OVERALL BY DRY AND BENIGN WEATHER. SUNDAY NIGHT THE WASHED OUT BOUNDARY WILL BE STRETCHED FROM SOUTHERN MN INTO CENTRAL WI. THIS WILL BE THE MOST LIKELY OPPORTUNITY FOR SHOWERS AND THUNDERSTORMS AS A SHORTWAVE MOVES OVERHEAD ON THE NORTHERN PERIPHERY OF THE SOUTHERN PLAINS MID LEVEL RIDGE. MOISTURE CONVERGENCE IS ADMITTEDLY BETTER TO THE SOUTH...BUT WE WILL HAVE PLENTY OF ANTECEDENT MOISTURE TO COMBINE WITH THE LIFT PROVIDED BY THE SHORTWAVE TROUGH. MONDAY MORNING WILL LIKELY BE MET WITH LINGERING SHOWERS AND THUNDERSTORMS OVER SOUTHEAST MN...BUT EXPECT THE BOUNDARY AND ASSOCIATED PRECIP TO BE OUT OF THE AREA BY THE AFTERNOON. MONDAY NIGHT AND TUESDAY BRINGS THE ARRIVAL OF BROAD SURFACE HIGH PRESSURE...WHICH WILL TRANSLATE TO LIGHT WINDS...MOSTLY CLEAR/SUNNY SKIES...AND SEASONAL TEMPS. COULD SEE SOME FOG FORMATION DURING THE OVERNIGHT PERIODS...BUT AN OTHERWISE A BENIGN WEATHER FORECAST WITH FEW CONCERNS IS ANTICIPATED INTO THURSDAY. THURSDAY NOW LOOKS TO FEATURE SMALL SHOWER AND THUNDERSTORM CHANCES WITH THE ARRIVAL OF A WEAK BOUNDARY ACROSS THE AREA AS A WEAK MID LEVEL TROUGH SKIRTS THE INTERNATIONAL BORDER. HAVE INCLUDED 20-30 POPS ON THURSDAY AND THURSDAY NIGHT...BUT IT CERTAINLY DOES NOT LOOK TO BE A WASHOUT. HIGH TEMPS THROUGH THE PERIOD WILL VARY FROM THE UPPER 70S TO LOWER 80S...WITH THE EXCEPTION OF THURSDAY WHEN SLIGHTLY HIGHER TEMPS ARE EXPECTED AHEAD OF THE APPROACHING BOUNDARY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1255 PM CDT SAT AUG 8 2015 -SHRA/ISOLD -TSRA OVER MUCH OF CENTRAL MN LATE THIS MORNING. THIS ARE BEING GENERATED AHEAD OF SURFACE BOUNDARY OVER THE DAKOTAS WITH SOME WEAK LOWER LEVEL FRONTOGENESIS/WAA. LATEST HRRR TRENDS SHOW THIS AREA MOVING EAST THE REST OF THE AFTERNOON. SOME REDEVELOPMENT EXPECTED ALONG/AHEAD OF THE BOUNDARY...MAINLY OVER THE NORTHWEST AREA/KAXN/KSTC INTO THE EVENING. APPEAR ACTIVITY WILL BE MAINLY DIURNAL WITH WEAKENING TREND EXPECTED BY SUNSET. MVFR CIGS CURRENTLY OVER WISCONSIN WILL LIFT THIS AFTERNOON AND MAY BREAK OUT IN SPOTS. OTHERWISE MAINLY VFR OUTSIDE OF -SHRA/-TSRA WHICH WILL REMAIN WIDELY SCT/ISOLD. IF THE SKY CLEARS OUT SIGNIFICANTLY...WILL LIKELY SEE MORE FOG DEVELOP. MOST OF THE AREA IS EXPECTED TO MAINTAIN SOME CLOUD COVER WHICH SHOULD LIMIT SIGNIFICANT FOG AT TAF SITES. KMSP...VFR EXPECTED WITH MIX OF CLOUD HEIGHTS INTO THE AFTERNOON. -SHRA BAND OVER CENTRAL MN WILL AFFECT THE AREA THROUGH ABOUT 22Z OR SO. CONFIDENCE ON THUNDER IS LOW AT THIS TIME. BETTER CHANCE OF THAT NEAR THE SURFACE BOUNDARY TO THE NORTHWEST AND IN SOME CLEARING OVER SOUTH CENTRAL MN. SHOULD SEE ANY SHOWERS COME TO AN END THIS EVENING AND THEN REDEVELOPMENT POSSIBLE INTO SUNDAY AFTERNOON/EVENING WITH THE FRONT. SFC WINDS SE-S THIS AFTERNOON BECOMING LIGHT OVERNIGHT. /OUTLOOK FOR KMSP/ SUN NITE....VFR. CHC MVFR CIGS -TSRA. WINDS NW 5-10 KNOTS. MON-TUE...VFR. WINDS NW 5-10 KTS. WED...VFR. WINDS SW 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...DWE LONG TERM...LS AVIATION...DWE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1254 PM CDT SAT AUG 8 2015 .UPDATED FOR 18Z AVIATION DISCUSSION... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 418 AM CDT SAT AUG 8 2015 MAIN CONCERN FOR THE SHORT TERM REMAINS THE CHANCE OF SHOWERS AND THUNDERSTORMS. TROUGH EXTENDING FROM LARGE UPPER LOW IN SOUTHERN MANITOBA EXTENDS TO MN AND SD...BUT ITS SOUTHERN REACH IS CERTAINLY BEING AFFECTED BY THE MCS IN IOWA. HEIGHTS BEGIN RISING SLIGHTLY THIS AFTERNOON ONCE THE MCS PASSES THE REGION. SLIGHT RIDGING CONTINUES INTO THIS EVENING OVER MN AND WI...UNTIL THE NEXT WEAK SHORT WAVE APPROACHES LATE TONIGHT...BUT THE IMPACT OF THAT WILL MAINLY BE ON SUNDAY. HAVE KEPT POPS FOR LATE TONIGHT IN WESTERN SECTIONS. MEANWHILE...SPOTTY SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP EARLY THIS MORNING FROM NORTHERN MN INTO SE SD AND SW MN. SHEAR VALUES ARE OK FOR STORMS BUT LOW AND MID LEVEL LAPSE RATES ARE RATHER POOR TODAY AND TONIGHT. A VARIETY OF CAMS DID FLAG THE RECENT DEVELOPMENT OF STORMS IN EASTERN SD...AND THIS IS EVIDENT IN THE STORMS RECENTLY DEVELOPED IN EASTERN SD. WILL NEED TO CONTINUE THE MENTION OF POPS THIS MORNING...ESPECIALLY IN WEST CENTRAL AND CENTRAL MN. MAIN THERMAL GRADIENT IS DRAPED FROM NORTHEAST MN TO THE WEST CENTRAL...AND THIS IS WHERE STORMS COULD REDEVELOP LATER THIS AFTERNOON WITH ENOUGH HEATING. LOW CLOUDS FROM RICE LAKE TO EAU CLAIRE AREA WILL GRADUALLY DIMINISH LATER THIS MORNING. A LITTLE DENSE FOG HAS FORMED JUST ON THE PERIPHERY OF THE LOW CLOUDS...BUT THIS SHOULD DISSIPATE DURING THE MID MORNING AFTER SOME HEATING. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 418 AM CDT SAT AUG 8 2015 MINNESOTA AND WISCONSIN WILL BE BETWEEN DISTURBANCES ON SUNDAY. THE SATURDAY NIGHT MCS ACROSS IOWA WILL BE HEADED EAST ACROSS NORTHERN AND CENTRAL IL SUNDAY MORNING...WITH THE LAST OF THE WESTERN ENERGY EJECTING EASTWARD ACROSS THE DAKOTAS BY AFTERNOON. THIS LEAVES THE AREA WITH LITTLE TO SUPPORT THUNDERSTORM DEVELOPMENT UNTIL THE NORTHERN PLAINS ENERGY ARRIVES SUNDAY NIGHT. POPS WERE INCREASED ACROSS MN SUNDAY NIGHT AS THIS WAVE TRACKS EAST SOUTHEASTWARD ON THE NORTHEAST PERIPHERY OF THE RETROGRADING MID LEVEL RIDGE TO THE SOUTH. MODELS ARE IN PRETTY GOOD AGREEMENT IN ADVERTISING SHOWERS AND THUNDERSTORMS ACROSS WRN/SRN MN SUNDAY NIGHT. RAINFALL AMOUNTS SHOULD NOT BE ALL THAT SIGNIFICANT ON A WIDESPREAD BASIS WITH THE ABSENCE OF A LLJ HELPING TO ORGANIZE THE ACTIVITY...BUT PW VALUES NEARING 1.75 INCHES WILL LEND CREDENCE TO LOCALIZED HEAVY RAINFALL RATES TOWARD SOUTHWESTERN MINNESOTA. AFTER THAT PIECE OF ENERGY EXITS TO THE SOUTHEAST MONDAY MORNING...SURFACE HIGH PRESSURE WILL SLOWLY TRACK SOUTHEAST ACROSS THE MISSISSIPPI VALLEY NEXT WEEK. A GRADUAL WARMING TREND CAN BE EXPECTED WITH THICKNESSES BUILDING THROUGH THE WEEK. COULD SEE A WEAK FRONT PUSH THROUGH LATE WEEK IF ANOTHER TROUGH SWINGS THROUGH EASTERN CANADA. THIS WOULD BRING THE NEXT LOW CHANCE OF STORMS. OTHERWISE...SEVERAL DAYS OF DRY WEATHER ARE EXPECTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1255 PM CDT SAT AUG 8 2015 -SHRA/ISOLD -TSRA OVER MUCH OF CENTRAL MN LATE THIS MORNING. THIS ARE BEING GENERATED AHEAD OF SURFACE BOUNDARY OVER THE DAKOTAS WITH SOME WEAK LOWER LEVEL FRONTOGENESIS/WAA. LATEST HRRR TRENDS SHOW THIS AREA MOVING EAST THE REST OF THE AFTERNOON. SOME REDEVELOPMENT EXPECTED ALONG/AHEAD OF THE BOUNDARY...MAINLY OVER THE NORTHWEST AREA/KAXN/KSTC INTO THE EVENING. APPEAR ACTIVITY WILL BE MAINLY DIURNAL WITH WEAKENING TREND EXPECTED BY SUNSET. MVFR CIGS CURRENTLY OVER WISCONSIN WILL LIFT THIS AFTERNOON AND MAY BREAK OUT IN SPOTS. OTHERWISE MAINLY VFR OUTSIDE OF -SHRA/-TSRA WHICH WILL REMAIN WIDELY SCT/ISOLD. IF THE SKY CLEARS OUT SIGNIFICANTLY...WILL LIKELY SEE MORE FOG DEVELOP. MOST OF THE AREA IS EXPECTED TO MAINTAIN SOME CLOUD COVER WHICH SHOULD LIMIT SIGNIFICANT FOG AT TAF SITES. KMSP...VFR EXPECTED WITH MIX OF CLOUD HEIGHTS INTO THE AFTERNOON. -SHRA BAND OVER CENTRAL MN WILL AFFECT THE AREA THROUGH ABOUT 22Z OR SO. CONFIDENCE ON THUNDER IS LOW AT THIS TIME. BETTER CHANCE OF THAT NEAR THE SURFACE BOUNDARY TO THE NORTHWEST AND IN SOME CLEARING OVER SOUTH CENTRAL MN. SHOULD SEE ANY SHOWERS COME TO AN END THIS EVENING AND THEN REDEVELOPMENT POSSIBLE INTO SUNDAY AFTERNOON/EVENING WITH THE FRONT. SFC WINDS SE-S THIS AFTERNOON BECOMING LIGHT OVERNIGHT. /OUTLOOK FOR KMSP/ SUN NITE....VFR. CHC MVFR CIGS -TSRA. WINDS NW 5-10 KNOTS. MON-TUE...VFR. WINDS NW 5-10 KTS. WED...VFR. WINDS SW 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...TDK LONG TERM...BORGHOFF AVIATION...DWE
AREA FORECAST DISCUSSION
NWS DULUTH MN
335 AM CDT SAT AUG 8 2015 .UPDATE... ISSUED AT 331 AM CDT SAT AUG 8 2015 UPDATED TO EXPAND FOG ADVISORY TO ST. CROIX RIVER VALLEY OF PINE AND BURNETT COUNTY...WHERE VISIBILITIES ARE CURRENTLY A HALF MILE...AND SHOULD ONLY GET WORSE IN THE NEXT FEW HOURS. EXPIRATION TIME REMAINS THE SAME. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 320 AM CDT SAT AUG 8 2015 COMPLICATED WEATHER SCENE OUT THERE THIS MORNING WITH A STRONG SURFACE LOW OVER MANITOBA...AND A WEAK FRON DRAPED SOUTH ACROSS THE EASTERN DAKOTAS. LAST EVENING THUNDERSTORMS DEVELOPED ALONG THIS FRONT...AND HAVE PUSHED EAST INTO THE FOREAST AREA EARLY THIS MORNING. THEY HAVE BEEN MAINTAINING STRENGTH ACROSS THE WESTERN CWA...BUT ONCE THEY GET INTO THE CENTRAL PORTIONS OF THE CWA THEY HAVE BEEN DIMINISHING RAPIDLY DUE TO THE LACK OF INSTABILITY FARTHER EAST. ALSO OF CONCERN THIS MORNING IS THE FOG. LAST NIGHTS RAINFALL CREATED EXCELLENT PRECONDITIONS FOR FOG...AND WITH OUR TEMPERATURES AND DEWPOINTS IN THE MIDDLE-UPPER 50S HERE WE ARE WITH FOG OVER MUCH OF THE FORECAST AREA. IT IS WORST AROUND LAKE SUPERIOR FROM ASHLAND...THROUGH THE TWIN PORTS AND UP THE NORTH SHORE WHERE A QUARTER MILE VISIBILITY IS PRETTY COMMON. ANY STORMS THAT GET FAR ENOUGH EAST TO MOVE ACROSS THE FOG IS LIKELY TO BRING THE VISIBILITY UP TEMPORARILY...BUT IT SHOULD GO RIGHT BACK DOWN. FOG SHOULD DISSIPATE WITH THE INCREASING TEMPERATURES IN THE MORNING SO HAVE PUT OUT A DENSE FOG ADVISORY FOR THE WORST AFFECTED AREAS UNTIL 10 AM. TODAY THE EARLY MORNING CONVECTION IS LIKELY TO DISSIPATE IN THE NEXT 3-6 HOURS...ESPECIALLY AS IT IS ALREADY SHOWING SIGNS OF WEAKENING WITH WEAKER STORMS AND MORE STRATIFORM APPEARANCE ON RADAR. IN COMBINATION WITH THE WEAKENING TREND AS STORMS MOVE EAST...EXPECT US TO BE DOWN TO JUST SHOWERS BY SUNRISE OR SHORTLY AFTER. HOWEVER...THIS IS UNLIKELY TO LAST AS INSTABILITY WILL BUILD ONCE AGAIN AHEAD OF THE COLD FRONT AS IT SLOWLY MOVES INTO THE WESTERN CWA THIS AFTERNOON. BETWEEN THAT AND THE RESPECTABLE SHEAR THAT WILL BE OVER THE AREA THIS AFTERNOON WE SHOULD HAVE SOME STRONG TO EVEN A FEW SEVERE STORMS THIS AFTERNOON AND EVENING AS THE FRONT SAGS SLOWLY ACROSS NORTHERN MINNESOTA. THE FRONT SHOULD CONTINUE TO SAG SOUTHEAST OVERNIGHT TONIGHT...AND CONTINUE ON INTO NORTHWEST WISCONSIN FOR SUNDAY. HOWEVER...ON SUNDAY THE CONVERGENCE ALONG THE BOUNDARY IS MUCH WEAKER...THE SHEAR IS MUCH WEAKER AS IS THE INSTABILITY...SO DO NOT EXPECT AS MUCH INTENSITY OR COVERAGE FROM THE STORMS AND HAVE GONE WITH LOWER POPS. OTHERWISE...TEMPERATURES TO REMAIN SEASONABLE...WITH COOLER TEMPS NEAR THE LAKE AS USUAL. EXPECT FOG AGAIN ACROSS THE AREA TONIGHT WITH THE RECENT RAINFALL AND LIGHT WINDS...AND HAVE PUT IN AREAS OF FOG FOR A LARGE PORTION OF THE AREA. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 320 AM CDT SAT AUG 8 2015 A WEAKENING UPPER LEVEL TROF IS FORECAST TO MOVE OUT OF THE AREA SUNDAY EVENING...BUT NOT BEFORE DROPPING SOME RAIN ALONG THE SOUTHERN EDGE OF THE REGION. THIS ACTIVITY WILL QUICKLY DEPART BY 06Z AND HAVE REMOVED THE POPS THEREAFTER AS HIGH PRESSURE IS BUILDING IN. ON MONDAY...EVEN THOUGH HIGH PRESSURE COVERS THE AREA...AN UPPER LEVEL TROF WILL SWING THROUGH THE ARROWHEAD AND HAVE POPS TO REFLECT THIS. THE TROF MOVES EAST OF THE AREA MONDAY NIGHT LEAVING THE SFC HIGH IN CHARGE. UPPER LEVEL RIDGING EDGES BACK ACROSS THE REGION TUESDAY WHILE THE SFC HIGH REMAINS NEARBY. THE RIDGING PREVAILS THROUGH WEDNESDAY. WEDNESDAY NIGHT FINDS A MID LEVEL TROF MOVING ACROSS THE ARROWHEAD. THE GFS IS SUFFERING FROM CONVECTIVE/GRIDSCALE FEEDBACK AND PUSHES A LARGE COLD FRONT INTO NE MN. MEANWHILE...THE ECMWF HAS A WEAK SFC TROF ALONG THE CANADIAN BORDER WITH SOME LIGHT QPF WITH THE GEM FURTHER TO THE WEST WITH THE TROF AND NO RAIN. USED A BLEND OF THE GEM/ECMWF FOR POPS. MODEL DIFFERENCES BECOME QUITE LARGE THURSDAY AND FRIDAY WITH THE HANDLING OF AN UPPER TROF AND ASSOCIATED FRONTAL BOUNDARY. KEPT WITH THE BLEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 106 AM CDT SAT AUG 8 2015 A FRONTAL BOUNDARY WILL CONTINUE TO SLOWLY MOVE INTO THE NORTHLAND DURING THE FORECAST PERIOD. THIS HAS GENERATED SHOWERS AND STORMS OVER WESTERN AND NORTH CENTRAL MINNESOTA. CURRENTLY STORMS ARE MOVING THROUGH KINL. EXPECTING THIS ACTIVITY TO SPREAD EASTWARDS AND AFFECT ALL OTHER TERMINALS...EXCEPT FOR KHYR BETWEEN 07Z AND 12Z. THIS MATCHES WELL WITH THE CURRENT RADAR TRENDS ALONG WITH THE LAST SEVERAL HRRR RUNS. EXPECTING ALL TERMINALS TO SEE EITHER IFR OR LIFR CONDITIONS AT SOME POINT AS THE NIGHT PROGRESSES INTO THE EARLY MORNING HOURS. MOST CONFIDENT OF LIFR CIGS AND VISBYS FOR KDLH AND KHYR UNTIL 14Z TO 17Z. WILL SEE ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT DUE TO DAY TIME HEATING IN COMBINATION WITH THE FRONT MOVING THROUGH MINNESOTA SATURDAY AFTERNOON. THINK THAT KINL AND KBRD MAY BE ON THE BACKSIDE OF THE FRONT BY THE TIME THIS OCCURS...SO LEFT IN AS VCSH...AND EVENTUALLY BROUGHT KINL AND KBRD TO VFR CONDITIONS BETWEEN 21Z AND 02Z. EXPECTING ALL OTHER TERMINALS TO SEE SHOWERS AND STORMS DURING THE AFTERNOON...HOWEVER UNSURE ON THE EXACT LOCATION OF SPECIFIC STORMS...SO LEFT AS VCTS. SOME OF THESE STORMS MAY BE STRONG DURING THE AFTERNOON AND HEADING INTO THE EVENING. && .PRELIMINARY POINT TEMPS/POPS... DLH 72 60 78 58 / 40 50 10 10 INL 78 54 74 55 / 40 10 0 10 BRD 79 60 80 58 / 50 40 20 10 HYR 76 60 78 57 / 20 30 20 20 ASX 74 60 78 58 / 30 40 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ001>003- 006. MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ020-021- 037-038. LS...NONE. && $$ UPDATE...LE SHORT TERM...LE LONG TERM...GSF AVIATION...WL
AREA FORECAST DISCUSSION
NWS DULUTH MN
322 AM CDT SAT AUG 8 2015 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 320 AM CDT SAT AUG 8 2015 COMPLICATED WEATHER SCENE OUT THERE THIS MORNING WITH A STRONG SURFACE LOW OVER MANITOBA...AND A WEAK FRON DRAPED SOUTH ACROSS THE EASTERN DAKOTAS. LAST EVENING THUNDERSTORMS DEVELOPED ALONG THIS FRONT...AND HAVE PUSHED EAST INTO THE FOREAST AREA EARLY THIS MORNING. THEY HAVE BEEN MAINTAINING STRENGTH ACROSS THE WESTERN CWA...BUT ONCE THEY GET INTO THE CENTRAL PORTIONS OF THE CWA THEY HAVE BEEN DIMINISHING RAPIDLY DUE TO THE LACK OF INSTABILITY FARTHER EAST. ALSO OF CONCERN THIS MORNING IS THE FOG. LAST NIGHTS RAINFALL CREATED EXCELLENT PRECONDITIONS FOR FOG...AND WITH OUR TEMPERATURES AND DEWPOINTS IN THE MIDDLE-UPPER 50S HERE WE ARE WITH FOG OVER MUCH OF THE FORECAST AREA. IT IS WORST AROUND LAKE SUPERIOR FROM ASHLAND...THROUGH THE TWIN PORTS AND UP THE NORTH SHORE WHERE A QUARTER MILE VISIBILITY IS PRETTY COMMON. ANY STORMS THAT GET FAR ENOUGH EAST TO MOVE ACROSS THE FOG IS LIKELY TO BRING THE VISIBILITY UP TEMPORARILY...BUT IT SHOULD GO RIGHT BACK DOWN. FOG SHOULD DISSIPATE WITH THE INCREASING TEMPERATURES IN THE MORNING SO HAVE PUT OUT A DENSE FOG ADVISORY FOR THE WORST AFFECTED AREAS UNTIL 10 AM. TODAY THE EARLY MORNING CONVECTION IS LIKELY TO DISSIPATE IN THE NEXT 3-6 HOURS...ESPECIALLY AS IT IS ALREADY SHOWING SIGNS OF WEAKENING WITH WEAKER STORMS AND MORE STRATIFORM APPEARANCE ON RADAR. IN COMBINATION WITH THE WEAKENING TREND AS STORMS MOVE EAST...EXPECT US TO BE DOWN TO JUST SHOWERS BY SUNRISE OR SHORTLY AFTER. HOWEVER...THIS IS UNLIKELY TO LAST AS INSTABILITY WILL BUILD ONCE AGAIN AHEAD OF THE COLD FRONT AS IT SLOWLY MOVES INTO THE WESTERN CWA THIS AFTERNOON. BETWEEN THAT AND THE RESPECTABLE SHEAR THAT WILL BE OVER THE AREA THIS AFTERNOON WE SHOULD HAVE SOME STRONG TO EVEN A FEW SEVERE STORMS THIS AFTERNOON AND EVENING AS THE FRONT SAGS SLOWLY ACROSS NORTHERN MINNESOTA. THE FRONT SHOULD CONTINUE TO SAG SOUTHEAST OVERNIGHT TONIGHT...AND CONTINUE ON INTO NORTHWEST WISCONSIN FOR SUNDAY. HOWEVER...ON SUNDAY THE CONVERGENCE ALONG THE BOUNDARY IS MUCH WEAKER...THE SHEAR IS MUCH WEAKER AS IS THE INSTABILITY...SO DO NOT EXPECT AS MUCH INTENSITY OR COVERAGE FROM THE STORMS AND HAVE GONE WITH LOWER POPS. OTHERWISE...TEMPERATURES TO REMAIN SEASONABLE...WITH COOLER TEMPS NEAR THE LAKE AS USUAL. EXPECT FOG AGAIN ACROSS THE AREA TONIGHT WITH THE RECENT RAINFALL AND LIGHT WINDS...AND HAVE PUT IN AREAS OF FOG FOR A LARGE PORTION OF THE AREA. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 320 AM CDT SAT AUG 8 2015 A WEAKENING UPPER LEVEL TROF IS FORECAST TO MOVE OUT OF THE AREA SUNDAY EVENING...BUT NOT BEFORE DROPPING SOME RAIN ALONG THE SOUTHERN EDGE OF THE REGION. THIS ACTIVITY WILL QUICKLY DEPART BY 06Z AND HAVE REMOVED THE POPS THEREAFTER AS HIGH PRESSURE IS BUILDING IN. ON MONDAY...EVEN THOUGH HIGH PRESSURE COVERS THE AREA...AN UPPER LEVEL TROF WILL SWING THROUGH THE ARROWHEAD AND HAVE POPS TO REFLECT THIS. THE TROF MOVES EAST OF THE AREA MONDAY NIGHT LEAVING THE SFC HIGH IN CHARGE. UPPER LEVEL RIDGING EDGES BACK ACROSS THE REGION TUESDAY WHILE THE SFC HIGH REMAINS NEARBY. THE RIDGING PREVAILS THROUGH WEDNESDAY. WEDNESDAY NIGHT FINDS A MID LEVEL TROF MOVING ACROSS THE ARROWHEAD. THE GFS IS SUFFERING FROM CONVECTIVE/GRIDSCALE FEEDBACK AND PUSHES A LARGE COLD FRONT INTO NE MN. MEANWHILE...THE ECMWF HAS A WEAK SFC TROF ALONG THE CANADIAN BORDER WITH SOME LIGHT QPF WITH THE GEM FURTHER TO THE WEST WITH THE TROF AND NO RAIN. USED A BLEND OF THE GEM/ECMWF FOR POPS. MODEL DIFFERENCES BECOME QUITE LARGE THURSDAY AND FRIDAY WITH THE HANDLING OF AN UPPER TROF AND ASSOCIATED FRONTAL BOUNDARY. KEPT WITH THE BLEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 106 AM CDT SAT AUG 8 2015 A FRONTAL BOUNDARY WILL CONTINUE TO SLOWLY MOVE INTO THE NORTHLAND DURING THE FORECAST PERIOD. THIS HAS GENERATED SHOWERS AND STORMS OVER WESTERN AND NORTH CENTRAL MINNESOTA. CURRENTLY STORMS ARE MOVING THROUGH KINL. EXPECTING THIS ACTIVITY TO SPREAD EASTWARDS AND AFFECT ALL OTHER TERMINALS...EXCEPT FOR KHYR BETWEEN 07Z AND 12Z. THIS MATCHES WELL WITH THE CURRENT RADAR TRENDS ALONG WITH THE LAST SEVERAL HRRR RUNS. EXPECTING ALL TERMINALS TO SEE EITHER IFR OR LIFR CONDITIONS AT SOME POINT AS THE NIGHT PROGRESSES INTO THE EARLY MORNING HOURS. MOST CONFIDENT OF LIFR CIGS AND VISBYS FOR KDLH AND KHYR UNTIL 14Z TO 17Z. WILL SEE ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT DUE TO DAY TIME HEATING IN COMBINATION WITH THE FRONT MOVING THROUGH MINNESOTA SATURDAY AFTERNOON. THINK THAT KINL AND KBRD MAY BE ON THE BACKSIDE OF THE FRONT BY THE TIME THIS OCCURS...SO LEFT IN AS VCSH...AND EVENTUALLY BROUGHT KINL AND KBRD TO VFR CONDITIONS BETWEEN 21Z AND 02Z. EXPECTING ALL OTHER TERMINALS TO SEE SHOWERS AND STORMS DURING THE AFTERNOON...HOWEVER UNSURE ON THE EXACT LOCATION OF SPECIFIC STORMS...SO LEFT AS VCTS. SOME OF THESE STORMS MAY BE STRONG DURING THE AFTERNOON AND HEADING INTO THE EVENING. && .PRELIMINARY POINT TEMPS/POPS... DLH 72 60 78 58 / 40 50 10 10 INL 78 54 74 55 / 40 10 0 10 BRD 79 60 80 58 / 50 40 20 10 HYR 76 60 78 57 / 20 30 20 20 ASX 74 60 78 58 / 30 40 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ001>003. MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ020-021- 037. LS...NONE. && $$ SHORT TERM...LE LONG TERM...GSF AVIATION...WL
AREA FORECAST DISCUSSION
NWS DULUTH MN
106 AM CDT SAT AUG 8 2015 .UPDATE... ISSUED AT 106 AM CDT SAT AUG 8 2015 UPDATED AVIATION DISCUSSION BELOW FOR THE 06Z TAF ISSUANCE UPDATE ISSUED AT 841 PM CDT FRI AUG 7 2015 WE WENT AHEAD AND ISSUED A DENSE FOG ADVISORY FOR THE TWIN PORTS AND ALONG THE NORTH SHORE TONIGHT INTO SATURDAY MORNING. VISIBILITIES CONTINUE TO DROP AND THAT TREND WILL CONTINUE OVERNIGHT FOR MOST AREAS. UPDATE ISSUED AT 807 PM CDT FRI AUG 7 2015 WE HAVE MADE SOME UPDATES TO ADJUST POPS/FOG/CLOUDS THIS EVENING. A BROKEN LINE OF STORMS EXTENDED FROM SOUTHEAST MANITOBA INTO EASTERN SOUTH DAKOTA THIS EVENING AND WAS MOVING TOWARD THE EAST. THIS WAS OCCURRING IN AN AXIS OF MLCAPE AROUND 2000J/KG AND STEEP LAPSE RATES. THE CONVECTION HAS SHOWN SOME SIGNS OF WEAKENING AS IT PROGRESSES EAST...BUT A STRONG OR POSSIBLE ISOLATED SEVERE STORM WILL BE POSSIBLE OVER OUR WESTERN ZONES LATER THIS EVENING INTO THE EARLY MORNING HOURS. FOG HAS PERSISTED AROUND LAKE SUPERIOR AND WE MAY HAVE TO ISSUE A DENSE FOG ADVISORY FOR THE HEAD OF LAKE SUPERIOR NORTH ALONG PORTIONS OF THE NORTH SHORE. SEVERAL OBSERVATIONS WERE DOWN TO A QUARTER MILE. WE WILL WAIT A BIT LONGER BEFORE ISSUING. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 344 PM CDT FRI AUG 7 2015 MAIN CONCERN FOR TODAY IS THE POTENTIAL FOR THUNDERSTORMS LATE THIS AFTERNOON ACROSS NORTH-CENTRAL MINNESOTA...FOG OVERNIGHT...AND RAIN CHANCES THROUGH THE DAY SATURDAY. EARLY THIS AFTERNOON AN UPPER LOW EVIDENT ON WATER VAPOR SATELLITE IMAGERY WAS TRACKING ACROSS SOUTHERN SASKATCHEWAN EAST INTO SOUTHERN MANITOBA. THIS UPPER LOW AND ACCOMPANY SFC LOW WILL LIFT NORTHEAST INTO NORTHWESTERN ONTARIO OVER THE WEEKEND. A WEAK COLD FRONT ASSOCIATED WITH THIS LOW IS CURRENTLY OVER EASTERN NORTH DAKOTA AND WILL MOVE EAST INTO NORTHWESTERN MINNESOTA TONIGHT...THEN STALL OUT THROUGH MUCH OF SATURDAY AS IT IS DRAPED FROM LAKE OF THE WOODS IN NORTHERN MINNESOTA TO AROUND FARGO NORTH DAKOTA. THIS COLD FRONT WILL SERVE AS A BOUNDARY FOR ANY STORM INITIATION TONIGHT...AND AS A DRIVER FOR SHOWERS AND STORMS AS THEY MOVE ACROSS THE REGION TOMORROW. TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW NORMAL...ESPECIALLY ALONG THE NORTH SHORE OF LAKE SUPERIOR. LATE TODAY...CLEARING SKIES FROM WEST TO EAST. A CU FIELD WAS OBSERVED ON VISIBLE SATELLITE EARLY THIS AFTERNOON...NOT SURPRISING GIVEN THE INSTABILITY OVER NORTH CENTRAL MINNESOTA...MUCAPE VALUES 1500-2000 J/KG. IN ADDITION TO THE AFOREMENTIONED COLD FRONT CURRENTLY OVER EASTERN NORTH DAKOTA...A WEAK STATIONARY FRONT IS CURRENTLY ANALYZED FROM LAKE OF THE WOODS SOUTHEAST TO ABOUT MOOSE LAKE. WHILE MUCH OF THE CWA REMAINS CAPPED...THERE IS A NARROW CORRIDOR WHICH SPC MESOANALYSIS INDICATES HAS VERY LITTLE CIN LEFT...BUT LACK OF ANY LOCAL FORCING MECHANISM WILL LIKELY PREVENT ANY STORM DEVELOPMENT THROUGH THE AFTERNOON. TONIGHT...AN ISOLATED STORM OR TWO WILL FIRE ACROSS THE RED RIVER VALLEY THIS EVENING AND MOVE EAST INTO NORTH CENTRAL/NORTHEAST MINNESOTA TOWARDS THE MORNING. COVERAGE EXPECTED TO BE SPARSE...BUT WITH ELEVATED INSTABILITY AND 25-35 KTS DEEP LAYER SHEAR COULD SEE STORMS SUSTAIN INTO THE NIGHT. STORMS MAY BE CAPABLE OF SMALL HAIL/GUSTY WINDS...BUT SEVERE THREAT SHOULD BE MINIMAL. ELSEWHERE EXPECT AREAS OF FOG TO DEVELOP ESPECIALLY NEAR LAKE SUPERIOR. OVERNIGHT LOWS IN THE MID TO UPPER 50S. SATURDAY...SCATTERED SHOWERS AND ISOLATED STORMS THROUGH THE DAY AND INTO THE NIGHT AS A COLD FRONT MOVES THROUGH. SEVERE THUNDERSTORMS NOT EXPECTED. NOT EXPECTING A COMPLETE WASHOUT...TRYING TO COMMUNICATE THIS WITH THE USE OF JUST 40-60 PERCENT POPS AND AREAL COVERAGE WORDING FOR THE WEATHER GRIDS...BUT A FEW DOWNPOURS POSSIBLE. HIGHS IN THE 70S...EXPECT NEAR LAKE SUPERIOR WHERE HIGHS WILL BE IN THE MID TO UPPER 60S. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 344 PM CDT FRI AUG 7 2015 VERY SLOW MOVING UPPER TROF AND ASSOCIATED LOW LEVEL FRONTAL ZONE WILL MOVE ACROSS THE REGION SAT NITE/SUN BRINGING A CHANCE OF SHOWERS/TSTORMS IN MOST AREAS. AT THIS TIME..IT APPEARS THAT THE AXIS OF HIGHEST QUALITY LOW LEVEL MOISTURE WILL REMAIN SOUTH OF THE DULUTH CWA. HOWEVER..THERE IS THE USUAL UNCERTAINTY IN PLACEMENT/TIMING OF CONVECTIVE POTENTIAL THAT WILL BE LARGELY DEPENDENT ON WHERE BOUNDARIES END UP AND OTHER CUMULATIVE EFFECTS FROM SEVERAL ROUNDS OF CONVECTION BEFORE THIS TIME PERIOD. WITH A WARM FRONTAL BOUNDARY PROGGED SOMEWHERE IN THE VICINITY OF THE I94 CORRIDOR AND THE NOSE OF A LLJ POINTED INTO WRN WI SAT NIGHT..THERE APPEARS TO BE AT LEAST SOME POTENTIAL FOR HEAVY RAIN IN THE ERN HALF OF OUR CWA SAT NIGHT INTO PERHAPS MIDDAY SUNDAY. AT LEAST SOME LOW CHANCES FOR PRECIP ARE EXPECTED TO LINGER INTO MONDAY AS THE FRONTAL ZONE IS EXPECTED TO TAKE ITS TIME MOVING SOUTHEASTWARD. IT WILL LIKELY TAKE UNTIL SOMETIME MONDAY NIGHT WHEN MORE SUBSTANTIAL LOW LEVEL RIDGING BUILDS BEFORE PRECIP WILL COMPLETELY END. IN ADDITION..THERE COULD BE SOME SMALL RISK OF SHOWERS ACROSS THE MN ARROWHEAD TUE..DEPENDING ON HOW COLD TEMPS GET ALOFT. THEREAFTER..HIGH PRESSURE SHOULD REMAIN IN CONTROL FOR MOST OF NEXT WEEK..WITH WARM DAYS..AND COOL NIGHTS ESPECIALLY ACROSS INTERIOR NE MINNESOTA. A WEAK FRONT INTERACTING WITH A BUILDING THERMAL RIDGE COULD BRING SMALL CHANCES FOR TSTORMS TO NORTHERN MN WED NIGHT INTO THURSDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 106 AM CDT SAT AUG 8 2015 A FRONTAL BOUNDARY WILL CONTINUE TO SLOWLY MOVE INTO THE NORTHLAND DURING THE FORECAST PERIOD. THIS HAS GENERATED SHOWERS AND STORMS OVER WESTERN AND NORTH CENTRAL MINNESOTA. CURRENTLY STORMS ARE MOVING THROUGH KINL. EXPECTING THIS ACTIVITY TO SPREAD EASTWARDS AND AFFECT ALL OTHER TERMINALS...EXCEPT FOR KHYR BETWEEN 07Z AND 12Z. THIS MATCHES WELL WITH THE CURRENT RADAR TRENDS ALONG WITH THE LAST SEVERAL HRRR RUNS. EXPECTING ALL TERMINALS TO SEE EITHER IFR OR LIFR CONDITIONS AT SOME POINT AS THE NIGHT PROGRESSES INTO THE EARLY MORNING HOURS. MOST CONFIDENT OF LIFR CIGS AND VISBYS FOR KDLH AND KHYR UNTIL 14Z TO 17Z. WILL SEE ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT DUE TO DAY TIME HEATING IN COMBINATION WITH THE FRONT MOVING THROUGH MINNESOTA SATURDAY AFTERNOON. THINK THAT KINL AND KBRD MAY BE ON THE BACKSIDE OF THE FRONT BY THE TIME THIS OCCURS...SO LEFT IN AS VCSH...AND EVENTUALLY BROUGHT KINL AND KBRD TO VFR CONDITIONS BETWEEN 21Z AND 02Z. EXPECTING ALL OTHER TERMINALS TO SEE SHOWERS AND STORMS DURING THE AFTERNOON...HOWEVER UNSURE ON THE EXACT LOCATION OF SPECIFIC STORMS...SO LEFT AS VCTS. SOME OF THESE STORMS MAY BE STRONG DURING THE AFTERNOON AND HEADING INTO THE EVENING. && .PRELIMINARY POINT TEMPS/POPS... DLH 59 78 58 77 / 40 20 10 10 INL 53 76 53 75 / 20 10 10 10 BRD 60 81 58 79 / 40 20 10 10 HYR 59 78 57 77 / 30 40 20 10 ASX 59 79 57 76 / 40 30 20 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ001. MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ020-021- 037. LS...NONE. && $$ UPDATE...WL SHORT TERM...JJM LONG TERM...MILLER AVIATION...WL
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1252 PM CDT SAT AUG 8 2015 .UPDATE: ISSUED AT 1033 AM CDT SAT AUG 8 2015 MCS REMNANTS HAVE BEEN STEADILY DECAYING ACROSS NORTH CENTRAL MO AND CENTRAL MO. POPS HAVE BEEN REDUCED ACCORDINGLY. KANOFSKY && .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 255 AM CDT SAT AUG 8 2015 MCS OVER EASTERN NEBRASKA AND NORTH CENTRAL KANSAS IS FORECAST TO DECAY AS IT MOVES EAST TODAY. HAVE INTRODUCED SOME SLIGHT CHANCE POPS INTO THE FORECAST FOR TODAY ALONG AND NORTH OF I-70 AS LATEST RUNS OF HRRR SUGGEST TAIL END OF THE DECAYING SYSTEM COULD BRING SOME ISOLATED TO SCATTERED SHOWERS/STORMS ACROSS THE AREA THIS MORNING AND EARLY AFTERNOON. TEMPERATURES ARE GOING TO BE TRICKY WITH CONVECTIVE DEBRIS CLOUD COVER. HAVE DECIDED TO STICK WITH A HEALTHY BLEND OF THE LATEST GUIDANCE AND LET THE DAY SHIFT ADJUST IF CLOUD COVER AND PRECIPITATION LIMIT INSOLATION. CVKING .LONG TERM: (TONIGHT THROUGH FRIDAY) ISSUED AT 255 AM CDT SAT AUG 8 2015 THUNDERSTORMS ARE EXPECTED TO REDEVELOP THIS AFTERNOON AND EVENING TO THE NORTHWEST OF THE CWA AND GROW UPSCALE INTO ANOTHER MCS. THE TRACK OF THE SYSTEM IS STILL FORECAST TO JUST GRAZE THE NORTHERN CWA TONIGHT...POSSIBLY PROPAGATING SOUTHEAST INTO SOUTH CENTRAL ILLINOIS ON SUNDAY MORNING. SEVERE WEATHER THREAT ASSOCIATED WITH THIS SYSTEM IS DAMAGING WIND GUSTS IN EXCESS OF 60 MPH. ANOTHER STRUGGLE BETWEEN CONVECTIVE DEBRIS AND VERY WARM TEMPERATURES ALOFT RESULTS IN A LOW CONFIDENCE TEMPERATURE FORECAST FOR SUNDAY. POTENTIAL IS CERTAINLY THERE FOR A HOT AND STEAMY DAY WITH HEAT INDEX VALUES ABOVE 105 DEGREES IN THE AFTERNOON AND EVENING. WILL CONTINUE TO HIGHLIGHT IN THE HWO AND ALLOW DAYSHIFT ANOTHER SET OF MODEL RUNS BEFORE ISSUING ANY HEADLINES FOR HEAT ON SUNDAY. CONVECTION SHOULD REDEVELOP AGAIN SUNDAY AFTERNOON AND CONTINUE INTO THE NIGHT...PROBABLY INITIALLY ON THE OUTFLOW BOUNDARY FROM THE MORNING MCS AND THEN THE COLD FRONT SETTLING SOUTH ACROSS THE REGION. HAVE KEPT HIGH CHANCE POPS BUT COULD SEE LATER SHIFTS INCREASING TO LIKELY. REMAINDER OF THE FORECAST FEATURES SLIGHTLY BELOW NORMAL TEMPERATURES AND DRY CONDITIONS AS NORTH TO NORTHWEST FLOW CONTINUES TO DELIVER HIGH PRESSURE TO THE REGION. CVKING && .AVIATION: (FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1234 PM CDT SAT AUG 8 2015 SPECIFICS FOR KUIN: LIGHT RAIN SHOWERS ARE POSSIBLE AT KUIN THROUGH 08/19Z. INITIALLY EASTERLY WINDS WILL BECOME SOUTHEASTERLY TO SOUTHERLY THROUGH THE PERIOD. A THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP UPSTREAM OVERNIGHT AND REACH KUIN AFTER 09/06Z. THERE IS SOME UNCERTAINTY ON WHERE THE COMPLEX WILL FORM AND WHEN IT MIGHT REACH KUIN. SPECIFICS FOR KCOU: INITIALLY SOUTHEASTERLY WINDS WILL BECOME SOUTHWESTERLY THROUGH THE TAF PERIOD IN RESPONSE TO AN APPROACHING LOW PRESSURE CENTER. A THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP UPSTREAM OVERNIGHT AND REACH KCOU AFTER 08/03Z. THERE IS SOME UNCERTAINTY ON WHERE THE COMPLEX WILL FORM AND WHEN IT MIGHT REACH KCOU. SPECIFICS FOR KSTL, KSUS, KCPS: LIGHT WINDS HAVE BEEN SLOW TO BECOME SOUTHEASTERLY THIS MORNING. LIGHT NORTHWEST TO WEST WINDS MAY PERSIST FOR A FEW MORE HOURS BEFORE TURNING SOUTHEASTERLY IN RESPONSE TO A DEVELOPING SURFACE LOW OVER KS. LIGHT WINDS AT KCOU HAVE RECENTLY TURNED SOUTHEASTERLY, SUGGESTING THAT THE WIND DIRECTION SHOULD FOLLOW SUIT AT ST. LOUIS METRO AREA TERMINALS WITHIN THE NEXT 2-5 HOURS. A THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP UPSTREAM OVERNIGHT AND PROGRESS SOUTHEASTWARDS, EVENTUALLY REACHING THE TERMINALS AFTER 09/09Z. KANOFSKY && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1250 PM CDT SAT AUG 8 2015 ...AVIATION UPDATE... .SHORT TERM...(Today through Sunday) Issued at 305 AM CDT SAT AUG 08 2015 First concern is ongoing convection across northern Kansas. Successive runs of the HRRR dissipates this area before it gets into the forecast area as does the RAP. Given expanding ridging would expect it to dissipate as it gets closer and stay north of the area. Will monitor radar trends and update as needed. For now will keep dry forecast for the morning hours. Attention then turns to the aforementioned expanding ridge across the area. This ridge will dominate the weather through Sunday with increasing heat and humidity. Heat advisory already in effect for much of the area from this afternoon through Sunday evening. Expect afternoon heat indicies in the 100 to 110 degree range both days. Biggest question will be the need to expand the advisory further eastward. Eastern Ozarks best chance to hit advisory criteria would be Sunday afternoon. Will allow day shift to evaluate it further. .LONG TERM...(Sunday night through Friday) Issued at 305 AM CDT SAT AUG 08 2015 Upper ridge retracts westward Sunday night and Monday allowing for a surface frontal boundary to slip southward into the area. This will bring our next chance for rain. Medium range models showing the better chances across central Missouri from late Sunday night into Monday morning. Pattern then dominated by a northwest flow regime with a surface high building southward into the area. This will result in quiet and dry weather with near to slightly below normal temperatures. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Pilots flying in and out of the southwest Missouri airports will experience VFR conditions over the next 24 hours. Southeast surface winds will be common as cloud cover begins to clear out for the rest of today and tonight. Thunderstorms will once again develop tonight, however, they are expected to remain north of the Ozarks. Safe Travels. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...HEAT ADVISORY until 10 PM CDT Sunday for MOZ055-056-066>069- 077>081-088>096-101>105. KS...HEAT ADVISORY until 10 PM CDT Sunday for KSZ073-097-101. && $$ SHORT TERM...Raberding LONG TERM...Raberding AVIATION...Cramer
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1231 PM CDT SAT AUG 8 2015 .DISCUSSION... Issued at 357 AM CDT SAT AUG 8 2015 As was anticipated last night, High Plains convection has congealed into an overnight MCS, which has made pretty good progression across northern Kansas, into north central Kansas. Models have had a rough time resolving exactly how this MCS will behave as it continues east. NAM consistently indicates that this complex will lose steam as the night progresses, but HRRR continues to insist that the complex will continue it, albeit weakening along the way, into the KC metro around sunrise. General thought as the morning progresses is a bit in the middle between these two solutions. The low level jet, apparently helping this complex persist is not very strong, but it also doesn`t appear to weaken much as one gets closer to the KC Metro. However, with the outflow from these storms already pushing out ahead of the complex, there is a good bet that stabilization of the effective layer will gradually occur and the storms will eventually lose their strength. Have the best chance of rain occurring across the far northwestern part of the CWA, in NW Missouri and NE Kansas, with diminishing (but non-zero) chances farther south and east. The focus then shifts to a complicated and conditional forecast for Saturday. Heat headlines currently ongoing will be allowed to continue, however confidence in these abnormally hot temperatures isn`t quite as high as it was yesterday. The aforementioned storm complex could change the evolution of the heat today across a good portion of the area. If the HRRR has its way and the complex dives all the way into the KC Metro it would bring at least some rain into the morning hours, with likely some cloud debris lingering around for a good portion of the morning. Even with all these qualifiers it`s still anticipated that the surface will recover, despite the stable rain cooled air moving through this morning. Expect heat indices to jump into the 100 to 105 range this afternoon with some locations perhaps reaching a little higher, mainly along and south of the MO River. That leads to the complications and conditions related to the storm chances later this afternoon and this evening. Mid level flow continues to reside over the central and northern plains with the center of the mid level ridge well south of the forecast area in the eastern southern plains. At the surface an unseasonably deep trough will form across the central High Plains and eject into the lower central plains. In response to this low to the west S/SE winds will pick up during the day, and likely overcome the cooler air, causing temperatures to jump back into the upper 80s, and very possibly the lower 90s. Across far northern Missouri, where cloud debris will likely be the thickest, as well as perhaps along or north of the warm front temperatures won`t get quite as warm as areas along and south of I-70. Depending on how well skies clear out this afternoon another round of storms will be possible, most likely across SE Nebraska, eastward across northern Missouri and southern Iowa. Most models continue to indicate a scenario where storms indeed fire later today. The lack of any appreciable mid level support for ascent this afternoon will exaggerate the capping inversion, which will keep storms at bay for at least the afternoon, into the evening hours. By the 22z to 00z time period the low level jet at 850 mb will pick up in intensity and likely give the final push needed to get storms to go up, likely in SE Nebraska or NE Kansas. Should these storms become surface based, which isn`t out of the question, a very impressive thermal and wind profile will be in place to bring some powerful storms. With the aforementioned SE surface flow, the strengthening LLJ, as well as the westerly mid level flow around 40 kts. The wind profile will be ample for supercell storms to form later this evening in the SE Neb/NW Mo/NE Ks area. ML CAPE values approaching 2000 to 3000 J/KG will provide the necessary instability to complement the deep layer shear nicely. Given that supercells are possible, hail and wind would be the most likely hazards with these storms; however not to be discounted, very impressive hodographs are present across the area of concern, with very long and clockwise curved hodographs. This would introduce a rather concerning tornado risk, especially for early August. Given the weak forcing it`s certainly possible that early storms will be somewhat discreet, which would increase the concern for supercellular storms. However, by 00z to 03z the discreet storms will likely congeal into a more robust complex and drive eastward, likely along the MO/IA border, bringing a wind and hail threat, along with a flash flooding threat. Given the LLJ maintenance overnight and PWAT values approaching 2 to 2.5 inches it`s possible that areas along and north of HWY 36 tonight could see some flooding and/or flash flooding. By early Sunday morning expect these storms to have moved off to the east and chances for rain gradually diminishing through the day on Sunday. For Sunday, warm conditions will continue for the forecast area, again, mainly across the southern zones. Anticipate temperatures again to reach the 90s, with heat indices in the 100 to 105 range across areas along and south of the MO River. But again, depending on how the area clears, the areal extent of the heat for Sunday is a bit up in the air, so will forgo a heat headline for now, but one may be necessary for areas along and south of the MO River. For Sunday, into Monday the large ridge will shift a little back to the west, putting the forecast area under more of an influence of the large trough over the Great Lakes region as opposed to the western ridge. A short wave trough will glide through the area on Monday, which should bring another chance for some rain, as well as a cooler air mass. For the rest of the week, expect temperatures to be a bit more comfortable with temperatures generally in the 80s. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Issued at 1231 PM CDT SAT AUG 8 2015 Main concerns with afternoon forecast involve possibilities for renewed convection later today/evening as a seasonably strong sfc low tracks east from the central High Plains. Current thinking is main show will remain north of Kansas City terminals later tonight...with main threats confined to STJ after the 00z time frame. Considering the amount of uncertainty on just where convection does form...have decided to offer a VCTS mention at STJ beginning at 2z or so. Once convective trends are better established...updates will be issued accordingly. Otherwise...expect VFR conditions at remaining sites with southeast winds eventually becoming southwest after 12z Sunday morning. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...HEAT ADVISORY until 9 PM CDT this evening for KSZ025-057-060-102. EXCESSIVE HEAT WARNING until 9 PM CDT this evening for KSZ103>105. MO...HEAT ADVISORY until 9 PM CDT this evening for MOZ011>014-020>023- 030-031-038-039-043>046-053-054. EXCESSIVE HEAT WARNING until 9 PM CDT this evening for MOZ028- 029-037. && $$ DISCUSSION...Leighton AVIATION...32
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1036 AM CDT SAT AUG 8 2015 .UPDATE: ISSUED AT 1033 AM CDT SAT AUG 8 2015 MCS REMNANTS HAVE BEEN STEADILY DECAYING ACROSS NORTH CENTRAL MO AND CENTRAL MO. POPS HAVE BEEN REDUCED ACCORDINGLY. KANOFSKY && ISSUED AT 434 AM CDT SAT AUG 8 2015 WILL BE ISSUING A DENSE FOG ADVISORY THROUGH 13Z FOR THE SOUTHERN MISSOURI COUNTIES IN THE CWA WHERE THE VISIBILITY HAS DROPPED TO 1/4SM. HAVE ALSO ADJUSTED POPS UP TO LIKELY CATEGORY FOR THE NORTHERN CWA WHERE REMNANTS OF THE MCS WILL BE TRACKING THIS MORNING. CVKING && .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 255 AM CDT SAT AUG 8 2015 MCS OVER EASTERN NEBRASKA AND NORTH CENTRAL KANSAS IS FORECAST TO DECAY AS IT MOVES EAST TODAY. HAVE INTRODUCED SOME SLIGHT CHANCE POPS INTO THE FORECAST FOR TODAY ALONG AND NORTH OF I-70 AS LATEST RUNS OF HRRR SUGGEST TAIL END OF THE DECAYING SYSTEM COULD BRING SOME ISOLATED TO SCATTERED SHOWERS/STORMS ACROSS THE AREA THIS MORNING AND EARLY AFTERNOON. TEMPERATURES ARE GOING TO BE TRICKY WITH CONVECTIVE DEBRIS CLOUD COVER. HAVE DECIDED TO STICK WITH A HEALTHY BLEND OF THE LATEST GUIDANCE AND LET THE DAY SHIFT ADJUST IF CLOUD COVER AND PRECIPITATION LIMIT INSOLATION. CVKING .LONG TERM: (TONIGHT THROUGH FRIDAY) ISSUED AT 255 AM CDT SAT AUG 8 2015 THUNDERSTORMS ARE EXPECTED TO REDEVELOP THIS AFTERNOON AND EVENING TO THE NORTHWEST OF THE CWA AND GROW UPSCALE INTO ANOTHER MCS. THE TRACK OF THE SYSTEM IS STILL FORECAST TO JUST GRAZE THE NORTHERN CWA TONIGHT...POSSIBLY PROPOGATING SOUTHEAST INTO SOUTH CENTRAL ILLINOIS ON SUNDAY MORNING. SEVERE WEATHER THREAT ASSOCIATED WITH THIS SYSTEM IS DAMAGING WIND GUSTS IN EXCESS OF 60 MPH. ANOTHER STRUGGLE BETWEEN CONVECTIVE DEBRIS AND VERY WARM TEMPERATURES ALOFT RESULTS IN A LOW CONFIDENCE TEMPERATURE FORECAST FOR SUNDAY. POTENTIAL IS CERTAINLY THERE FOR A HOT AND STEAMY DAY WITH HEAT INDEX VALUES ABOVE 105 DEGREES IN THE AFTERNOON AND EVENING. WILL CONTINUE TO HIGHLIGHT IN THE HWO AND ALLOW DAYSHIFT ANOTHER SET OF MODEL RUNS BEFORE ISSUING ANY HEADLINES FOR HEAT ON SUNDAY. CONVECTION SHOULD REDEVELOP AGAIN SUNDAY AFTERNOON AND CONTINUE INTO THE NIGHT...PROBABLY INITIALLY ON THE OUTFLOW BOUNDARY FROM THE MORNING MCS AND THEN THE COLD FRONT SETTLING SOUTH ACROSS THE REGION. HAVE KEPT HIGH CHANCE POPS BUT COULD SEE LATER SHIFTS INCREASING TO LIKELY. REMAINDER OF THE FORECAST FEATURES SLIGHTLY BELOW NORMAL TEMPERATURES AND DRY CONDITIONS AS NORTH TO NORTHWEST FLOW CONTINUES TO DELIVER HIGH PRESSURE TO THE REGION. CVKING && .AVIATION: (FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 654 AM CDT SAT AUG 8 2015 LOW VSBYS IN FOG SHOULD IMPROVE OVER THE NEXT HOUR OR TWO TO VFR. UNTIL THEN...MVFR AND IFR VSBYS WILL PREVAIL ACROSS PARTS OF EASTERN AND CENTRAL MISSOURI. ADDITIONALLY...LIGHT SHOWERS CURRENTLY OVER WESTERN MISSOURI WILL LIKELY DRIFT INTO PARTS OF NORTHEAST MISSOURI BETWEEN 14Z AND 16Z. DON`T EXPECT MUCH IMPACT FROM THIS LIGHT RAIN OTHER THAN WET RUNWAYS. ONCE FOG DISSIPATES AND RAIN EVAPORATES EXPECT VFR FLIGHT CONDITIONS TO PREVAIL INTO THE EVENING HOURS. ANOTHER COMPLEX OF STORMS IS EXPECTED TO FORM TONIGHT OVER IOWA AND THE SOUTHERN FRINGES OF THE COMPLEX WILL LIKELY IMPACT NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS AFTER 06Z. SPECIFICS FOR KSTL: VFR FLIGHT CONDITIONS AND LIGHT SOUTHEAST FLOW IS EXPECTED TO PREVAIL AT LAMBERT AT LEAST THROUGH TONIGHT. THERE IS A SLIGHT CHANCE OF ISOLATED THUNDERSTORMS LATE THIS AFTERNOON, BUT IF ANY STORMS DO FORM THE AREAL COVERAGE IS EXPECTED TO BE VERY LOW. THERE IS ANOTHER CHANCE FOR STORMS EARLY SUNDAY MORNING, BUT CONFIDENCE IN THE THUNDERSTORM TRENDS IS LOW AT THIS TIME SO HAVE LEFT MENTION OF STORMS OUR FOR NOW. CARNEY && .PRELIMINARY POINT TEMPS/POPS: SAINT LOUIS 90 76 95 75 / 20 20 30 40 QUINCY 84 71 89 70 / 40 60 40 20 COLUMBIA 90 75 94 72 / 40 20 20 40 JEFFERSON CITY 91 76 96 74 / 30 20 20 40 SALEM 87 72 91 73 / 10 10 30 40 FARMINGTON 88 72 94 74 / 10 10 20 40 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
717 AM CDT SAT AUG 8 2015 .UPDATE: ISSUED AT 434 AM CDT SAT AUG 8 2015 WILL BE ISSUING A DENSE FOG ADVISORY THROUGH 13Z FOR THE SOUTHERN MISSOURI COUNTIES IN THE CWA WHERE THE VISIBILITY HAS DROPPED TO 1/4SM. HAVE ALSO ADJUSTED POPS UP TO LIKELY CATEGORY FOR THE NORTHERN CWA WHERE REMNANTS OF THE MCS WILL BE TRACKING THIS MORNING. CVKING && .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 255 AM CDT SAT AUG 8 2015 MCS OVER EASTERN NEBRASKA AND NORTH CENTRAL KANSAS IS FORECAST TO DECAY AS IT MOVES EAST TODAY. HAVE INTRODUCED SOME SLIGHT CHANCE POPS INTO THE FORECAST FOR TODAY ALONG AND NORTH OF I-70 AS LATEST RUNS OF HRRR SUGGEST TAIL END OF THE DECAYING SYSTEM COULD BRING SOME ISOLATED TO SCATTERED SHOWERS/STORMS ACROSS THE AREA THIS MORNING AND EARLY AFTERNOON. TEMPERATURES ARE GOING TO BE TRICKY WITH CONVECTIVE DEBRIS CLOUD COVER. HAVE DECIDED TO STICK WITH A HEALTHY BLEND OF THE LATEST GUIDANCE AND LET THE DAY SHIFT ADJUST IF CLOUD COVER AND PRECIPITATION LIMIT INSOLATION. CVKING .LONG TERM: (TONIGHT THROUGH FRIDAY) ISSUED AT 255 AM CDT SAT AUG 8 2015 THUNDERSTORMS ARE EXPECTED TO REDEVELOP THIS AFTERNOON AND EVENING TO THE NORTHWEST OF THE CWA AND GROW UPSCALE INTO ANOTHER MCS. THE TRACK OF THE SYSTEM IS STILL FORECAST TO JUST GRAZE THE NORTHERN CWA TONIGHT...POSSIBLY PROPOGATING SOUTHEAST INTO SOUTH CENTRAL ILLINOIS ON SUNDAY MORNING. SEVERE WEATHER THREAT ASSOCIATED WITH THIS SYSTEM IS DAMAGING WIND GUSTS IN EXCESS OF 60 MPH. ANOTHER STRUGGLE BETWEEN CONVECTIVE DEBRIS AND VERY WARM TEMPERATURES ALOFT RESULTS IN A LOW CONFIDENCE TEMPERATURE FORECAST FOR SUNDAY. POTENTIAL IS CERTAINLY THERE FOR A HOT AND STEAMY DAY WITH HEAT INDEX VALUES ABOVE 105 DEGREES IN THE AFTERNOON AND EVENING. WILL CONTINUE TO HIGHLIGHT IN THE HWO AND ALLOW DAYSHIFT ANOTHER SET OF MODEL RUNS BEFORE ISSUING ANY HEADLINES FOR HEAT ON SUNDAY. CONVECTION SHOULD REDEVELOP AGAIN SUNDAY AFTERNOON AND CONTINUE INTO THE NIGHT...PROBABLY INITIALLY ON THE OUTFLOW BOUNDARY FROM THE MORNING MCS AND THEN THE COLD FRONT SETTLING SOUTH ACROSS THE REGION. HAVE KEPT HIGH CHANCE POPS BUT COULD SEE LATER SHIFTS INCREASING TO LIKELY. REMAINDER OF THE FORECAST FEATURES SLIGHTLY BELOW NORMAL TEMPERATURES AND DRY CONDITIONS AS NORTH TO NORTHWEST FLOW CONTINUES TO DELIVER HIGH PRESSURE TO THE REGION. CVKING && .AVIATION: (FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 654 AM CDT SAT AUG 8 2015 LOW VSBYS IN FOG SHOULD IMPROVE OVER THE NEXT HOUR OR TWO TO VFR. UNTIL THEN...MVFR AND IFR VSBYS WILL PREVAIL ACROSS PARTS OF EASTERN AND CENTRAL MISSOURI. ADDITIONALLY...LIGHT SHOWERS CURRENTLY OVER WESTERN MISSOURI WILL LIKELY DRIFT INTO PARTS OF NORTHEAST MISSOURI BETWEEN 14Z AND 16Z. DON`T EXPECT MUCH IMPACT FROM THIS LIGHT RAIN OTHER THAN WET RUNWAYS. ONCE FOG DISSIPATES AND RAIN EVAPORATES EXPECT VFR FLIGHT CONDITIONS TO PREVAIL INTO THE EVENING HOURS. ANOTHER COMPLEX OF STORMS IS EXPECTED TO FORM TONIGHT OVER IOWA AND THE SOUTHERN FRINGES OF THE COMPLEX WILL LIKELY IMPACT NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS AFTER 06Z. SPECIFICS FOR KSTL: VFR FLIGHT CONDITIONS AND LIGHT SOUTHEAST FLOW IS EXPECTED TO PREVAIL AT LAMBERT AT LEAST THROUGH TONIGHT. THERE IS A SLIGHT CHANCE OF ISOLATED THUNDERSTORMS LATE THIS AFTERNOON, BUT IF ANY STORMS DO FORM THE AREAL COVERAGE IS EXPECTED TO BE VERY LOW. THERE IS ANOTHER CHANCE FOR STORMS EARLY SUNDAY MORNING, BUT CONFIDENCE IN THE THUNDERSTORM TRENDS IS LOW AT THIS TIME SO HAVE LEFT MENTION OF STORMS OUR FOR NOW. CARNEY && .PRELIMINARY POINT TEMPS/POPS: SAINT LOUIS 90 76 95 75 / 20 20 30 40 QUINCY 84 71 89 70 / 70 60 40 20 COLUMBIA 90 75 94 72 / 40 20 20 40 JEFFERSON CITY 91 76 96 74 / 30 20 20 40 SALEM 87 72 91 73 / 20 10 30 40 FARMINGTON 88 72 94 74 / 10 10 20 40 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR CRAWFORD MO- IRON MO-MADISON MO-REYNOLDS MO-ST. FRANCOIS MO-STE. GENEVIEVE MO-WASHINGTON MO. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
634 AM CDT SAT AUG 8 2015 .DISCUSSION... Issued at 357 AM CDT SAT AUG 8 2015 As was anticipated last night, High Plains convection has congealed into an overnight MCS, which has made pretty good progression across northern Kansas, into north central Kansas. Models have had a rough time resolving exactly how this MCS will behave as it continues east. NAM consistently indicates that this complex will lose steam as the night progresses, but HRRR continues to insist that the complex will continue it, albeit weakening along the way, into the KC metro around sunrise. General thought as the morning progresses is a bit in the middle between these two solutions. The low level jet, apparently helping this complex persist is not very strong, but it also doesn`t appear to weaken much as one gets closer to the KC Metro. However, with the outflow from these storms already pushing out ahead of the complex, there is a good bet that stabilization of the effective layer will gradually occur and the storms will eventually lose their strength. Have the best chance of rain occurring across the far northwestern part of the CWA, in NW Missouri and NE Kansas, with diminishing (but non-zero) chances farther south and east. The focus then shifts to a complicated and conditional forecast for Saturday. Heat headlines currently ongoing will be allowed to continue, however confidence in these abnormally hot temperatures isn`t quite as high as it was yesterday. The aforementioned storm complex could change the evolution of the heat today across a good portion of the area. If the HRRR has its way and the complex dives all the way into the KC Metro it would bring at least some rain into the morning hours, with likely some cloud debris lingering around for a good portion of the morning. Even with all these qualifiers it`s still anticipated that the surface will recover, despite the stable rain cooled air moving through this morning. Expect heat indices to jump into the 100 to 105 range this afternoon with some locations perhaps reaching a little higher, mainly along and south of the MO River. That leads to the complications and conditions related to the storm chances later this afternoon and this evening. Mid level flow continues to reside over the central and northern plains with the center of the mid level ridge well south of the forecast area in the eastern southern plains. At the surface an unseasonably deep trough will form across the central High Plains and eject into the lower central plains. In response to this low to the west S/SE winds will pick up during the day, and likely overcome the cooler air, causing temperatures to jump back into the upper 80s, and very possibly the lower 90s. Across far northern Missouri, where cloud debris will likely be the thickest, as well as perhaps along or north of the warm front temperatures won`t get quite as warm as areas along and south of I-70. Depending on how well skies clear out this afternoon another round of storms will be possible, most likely across SE Nebraska, eastward across northern Missouri and southern Iowa. Most models continue to indicate a scenario where storms indeed fire later today. The lack of any appreciable mid level support for ascent this afternoon will exaggerate the capping inversion, which will keep storms at bay for at least the afternoon, into the evening hours. By the 22z to 00z time period the low level jet at 850 mb will pick up in intensity and likely give the final push needed to get storms to go up, likely in SE Nebraska or NE Kansas. Should these storms become surface based, which isn`t out of the question, a very impressive thermal and wind profile will be in place to bring some powerful storms. With the aforementioned SE surface flow, the strengthening LLJ, as well as the westerly mid level flow around 40 kts. The wind profile will be ample for supercell storms to form later this evening in the SE Neb/NW Mo/NE Ks area. ML CAPE values approaching 2000 to 3000 J/KG will provide the necessary instability to complement the deep layer shear nicely. Given that supercells are possible, hail and wind would be the most likely hazards with these storms; however not to be discounted, very impressive hodographs are present across the area of concern, with very long and clockwise curved hodographs. This would introduce a rather concerning tornado risk, especially for early August. Given the weak forcing it`s certainly possible that early storms will be somewhat discreet, which would increase the concern for supercellular storms. However, by 00z to 03z the discreet storms will likely congeal into a more robust complex and drive eastward, likely along the MO/IA border, bringing a wind and hail threat, along with a flash flooding threat. Given the LLJ maintenance overnight and PWAT values approaching 2 to 2.5 inches it`s possible that areas along and north of HWY 36 tonight could see some flooding and/or flash flooding. By early Sunday morning expect these storms to have moved off to the east and chances for rain gradually diminishing through the day on Sunday. For Sunday, warm conditions will continue for the forecast area, again, mainly across the southern zones. Anticipate temperatures again to reach the 90s, with heat indices in the 100 to 105 range across areas along and south of the MO River. But again, depending on how the area clears, the areal extent of the heat for Sunday is a bit up in the air, so will forgo a heat headline for now, but one may be necessary for areas along and south of the MO River. For Sunday, into Monday the large ridge will shift a little back to the west, putting the forecast area under more of an influence of the large trough over the Great Lakes region as opposed to the western ridge. A short wave trough will glide through the area on Monday, which should bring another chance for some rain, as well as a cooler air mass. For the rest of the week, expect temperatures to be a bit more comfortable with temperatures generally in the 80s. && .AVIATION...(For the 12Z TAFS through 12Z Sunday Morning) Issued at 629 AM CDT SAT AUG 8 2015 Morning showers and thunderstorms will likely move out of the area by mid morning, with VFR conditions prevailing. Winds will pick up out of the southeast by mid to late morning around 15 to 20 kts. KSTJ could see some thunderstorm activity later tonight, but the bulk of it should remain north of KSTJ nearer to the IA/MO border. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...HEAT ADVISORY from Noon today to 9 PM CDT this evening for KSZ025-057-060-102. EXCESSIVE HEAT WARNING from Noon today to 9 PM CDT this evening for KSZ103>105. MO...HEAT ADVISORY from Noon today to 9 PM CDT this evening for MOZ011>014-020>023-030-031-038-039-043>046-053-054. EXCESSIVE HEAT WARNING from Noon today to 9 PM CDT this evening for MOZ028-029-037. && $$ DISCUSSION...Leighton AVIATION...Leighton
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
437 AM CDT SAT AUG 8 2015 .UPDATE: ISSUED AT 434 AM CDT SAT AUG 8 2015 WILL BE ISSUING A DENSE FOG ADVISORY THROUGH 13Z FOR THE SOUTHERN MISSOURI COUNTIES IN THE CWA WHERE THE VISIBILITY HAS DROPPED TO 1/4SM. HAVE ALSO ADJUSTED POPS UP TO LIKELY CATEGORY FOR THE NORTHERN CWA WHERE REMNANTS OF THE MCS WILL BE TRACKING THIS MORNING. CVKING && .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 255 AM CDT SAT AUG 8 2015 MCS OVER EASTERN NEBRASKA AND NORTH CENTRAL KANSAS IS FORECAST TO DECAY AS IT MOVES EAST TODAY. HAVE INTRODUCED SOME SLIGHT CHANCE POPS INTO THE FORECAST FOR TODAY ALONG AND NORTH OF I-70 AS LATEST RUNS OF HRRR SUGGEST TAIL END OF THE DECAYING SYSTEM COULD BRING SOME ISOLATED TO SCATTERED SHOWERS/STORMS ACROSS THE AREA THIS MORNING AND EARLY AFTERNOON. TEMPERATURES ARE GOING TO BE TRICKY WITH CONVECTIVE DEBRIS CLOUD COVER. HAVE DECIDED TO STICK WITH A HEALTHY BLEND OF THE LATEST GUIDANCE AND LET THE DAY SHIFT ADJUST IF CLOUD COVER AND PRECIPITATION LIMIT INSOLATION. CVKING .LONG TERM: (TONIGHT THROUGH FRIDAY) ISSUED AT 255 AM CDT SAT AUG 8 2015 THUNDERSTORMS ARE EXPECTED TO REDEVELOP THIS AFTERNOON AND EVENING TO THE NORTHWEST OF THE CWA AND GROW UPSCALE INTO ANOTHER MCS. THE TRACK OF THE SYSTEM IS STILL FORECAST TO JUST GRAZE THE NORTHERN CWA TONIGHT...POSSIBLY PROPOGATING SOUTHEAST INTO SOUTH CENTRAL ILLINOIS ON SUNDAY MORNING. SEVERE WEATHER THREAT ASSOCIATED WITH THIS SYSTEM IS DAMAGING WIND GUSTS IN EXCESS OF 60 MPH. ANOTHER STRUGGLE BETWEEN CONVECTIVE DEBRIS AND VERY WARM TEMPERATURES ALOFT RESULTS IN A LOW CONFIDENCE TEMPERATURE FORECAST FOR SUNDAY. POTENTIAL IS CERTAINLY THERE FOR A HOT AND STEAMY DAY WITH HEAT INDEX VALUES ABOVE 105 DEGREES IN THE AFTERNOON AND EVENING. WILL CONTINUE TO HIGHLIGHT IN THE HWO AND ALLOW DAYSHIFT ANOTHER SET OF MODEL RUNS BEFORE ISSUING ANY HEADLINES FOR HEAT ON SUNDAY. CONVECTION SHOULD REDEVELOP AGAIN SUNDAY AFTERNOON AND CONTINUE INTO THE NIGHT...PROBABLY INITIALLY ON THE OUTFLOW BOUNDARY FROM THE MORNING MCS AND THEN THE COLD FRONT SETTLING SOUTH ACROSS THE REGION. HAVE KEPT HIGH CHANCE POPS BUT COULD SEE LATER SHIFTS INCREASING TO LIKELY. REMAINDER OF THE FORECAST FEATURES SLIGHTLY BELOW NORMAL TEMPERATURES AND DRY CONDITIONS AS NORTH TO NORTHWEST FLOW CONTINUES TO DELIVER HIGH PRESSURE TO THE REGION. CVKING && .AVIATION: (FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1055 PM CDT FRI AUG 7 2015 WEAKENING COLD FRONT EXTENDING FROM A SURFACE LOW OVER WI SW INTO NORTHEAST MO WILL CONTINUE MOVING SOUTHEASTWARD LATE TONIGHT AND DISSIPATE. COULD NOT RULE OUT AN ISOLATED SHOWER/STORM ALONG THIS WEAK FRONT...BUT FOR NOW WILL LEAVE UIN TAF DRY. HIGH LEVEL CLOUDINESS WILL STREAM EASTWARD FROM THE PLAINS LATE TONIGHT... MAINLY FROM CONVECTION ACROSS KANSAS AND NEBRASKA. WITH LIGHT SURFACE WINDS AND RELATIVELY HIGH SURFACE DEW POINTS...THERE MAY BE SOME FOG LATE TONIGHT/EARLY SATURDAY MORNING...ALTHOUGH THE NAM MOS GUIDANCE APPEARS OVERDONE ON ITS STRATUS/FOG FORECAST AT THE TAF SITES. SOUTHEASTERLY SURFACE WINDS ON SATURDAY WITH SCATTERED DIURNAL CUMULUS ALONG WITH HIGH LEVEL CLOUDS AGAIN. SPECIFICS FOR KSTL: SOME HIGH LEVEL CLOUDS FOR LATE TONIGHT. LIGHT E-SELY SURFACE WIND LATE TONIGHT WILL STRENGTHEN TO AROUND 7-8 KNOTS SATURDAY AFTERNOON. SCATTERED DIURNAL CUMULUS CLOUDS WILL DEVELOP AGAIN FOR LATE SATURDAY MORNING AND AFTERNOON. GKS && .PRELIMINARY POINT TEMPS/POPS: SAINT LOUIS 91 76 95 75 / 10 20 30 40 QUINCY 87 71 89 70 / 50 60 40 20 COLUMBIA 90 75 94 72 / 30 20 20 40 JEFFERSON CITY 91 76 96 74 / 20 20 20 40 SALEM 87 72 91 73 / 10 10 30 40 FARMINGTON 88 72 94 74 / 5 10 20 40 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
358 AM CDT SAT AUG 8 2015 .DISCUSSION... Issued at 357 AM CDT SAT AUG 8 2015 As was anticipated last night, High Plains convection has congealed into an overnight MCS, which has made pretty good progression across northern Kansas, into north central Kansas. Models have had a rough time resolving exactly how this MCS will behave as it continues east. NAM consistently indicates that this complex will lose steam as the night progresses, but HRRR continues to insist that the complex will continue it, albeit weakening along the way, into the KC metro around sunrise. General thought as the morning progresses is a bit in the middle between these two solutions. The low level jet, apparently helping this complex persist is not very strong, but it also doesn`t appear to weaken much as one gets closer to the KC Metro. However, with the outflow from these storms already pushing out ahead of the complex, there is a good bet that stabilization of the effective layer will gradually occur and the storms will eventually lose their strength. Have the best chance of rain occurring across the far northwestern part of the CWA, in NW Missouri and NE Kansas, with diminishing (but non-zero) chances farther south and east. The focus then shifts to a complicated and conditional forecast for Saturday. Heat headlines currently ongoing will be allowed to continue, however confidence in these abnormally hot temperatures isn`t quite as high as it was yesterday. The aforementioned storm complex could change the evolution of the heat today across a good portion of the area. If the HRRR has its way and the complex dives all the way into the KC Metro it would bring at least some rain into the morning hours, with likely some cloud debris lingering around for a good portion of the morning. Even with all these qualifiers it`s still anticipated that the surface will recover, despite the stable rain cooled air moving through this morning. Expect heat indices to jump into the 100 to 105 range this afternoon with some locations perhaps reaching a little higher, mainly along and south of the MO River. That leads to the complications and conditions related to the storm chances later this afternoon and this evening. Mid level flow continues to reside over the central and northern plains with the center of the mid level ridge well south of the forecast area in the eastern southern plains. At the surface an unseasonably deep trough will form across the central High Plains and eject into the lower central plains. In response to this low to the west S/SE winds will pick up during the day, and likely overcome the cooler air, causing temperatures to jump back into the upper 80s, and very possibly the lower 90s. Across far northern Missouri, where cloud debris will likely be the thickest, as well as perhaps along or north of the warm front temperatures won`t get quite as warm as areas along and south of I-70. Depending on how well skies clear out this afternoon another round of storms will be possible, most likely across SE Nebraska, eastward across northern Missouri and southern Iowa. Most models continue to indicate a scenario where storms indeed fire later today. The lack of any appreciable mid level support for ascent this afternoon will exaggerate the capping inversion, which will keep storms at bay for at least the afternoon, into the evening hours. By the 22z to 00z time period the low level jet at 850 mb will pick up in intensity and likely give the final push needed to get storms to go up, likely in SE Nebraska or NE Kansas. Should these storms become surface based, which isn`t out of the question, a very impressive thermal and wind profile will be in place to bring some powerful storms. With the aforementioned SE surface flow, the strengthening LLJ, as well as the westerly mid level flow around 40 kts. The wind profile will be ample for supercell storms to form later this evening in the SE Neb/NW Mo/NE Ks area. ML CAPE values approaching 2000 to 3000 J/KG will provide the necessary instability to complement the deep layer shear nicely. Given that supercells are possible, hail and wind would be the most likely hazards with these storms; however not to be discounted, very impressive hodographs are present across the area of concern, with very long and clockwise curved hodographs. This would introduce a rather concerning tornado risk, especially for early August. Given the weak forcing it`s certainly possible that early storms will be somewhat discreet, which would increase the concern for supercellular storms. However, by 00z to 03z the discreet storms will likely congeal into a more robust complex and drive eastward, likely along the MO/IA border, bringing a wind and hail threat, along with a flash flooding threat. Given the LLJ maintenance overnight and PWAT values approaching 2 to 2.5 inches it`s possible that areas along and north of HWY 36 tonight could see some flooding and/or flash flooding. By early Sunday morning expect these storms to have moved off to the east and chances for rain gradually diminishing through the day on Sunday. For Sunday, warm conditions will continue for the forecast area, again, mainly across the southern zones. Anticipate temperatures again to reach the 90s, with heat indices in the 100 to 105 range across areas along and south of the MO River. But again, depending on how the area clears, the areal extent of the heat for Sunday is a bit up in the air, so will forgo a heat headline for now, but one may be necessary for areas along and south of the MO River. For Sunday, into Monday the large ridge will shift a little back to the west, putting the forecast area under more of an influence of the large trough over the Great Lakes region as opposed to the western ridge. A short wave trough will glide through the area on Monday, which should bring another chance for some rain, as well as a cooler air mass. For the rest of the week, expect temperatures to be a bit more comfortable with temperatures generally in the 80s. && .AVIATION...(For the 06Z TAFS through 06Z Saturday Night) Issued at 1203 AM CDT SAT AUG 8 2015 Mainly VFR expected through the period. Main concern will be potential thunderstorm complex reaching terminals in some weakened form between 09-14Z. Still expect mainly VFR conditions with this activity. Cloud canopy currently overspreading region will limit shallow fog potential. Otherwise, southeast winds will increase to AOA 12kts by mid- morning. Additional chances for storms during the afternoon/evening look to remain north of terminals through TAF period. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...HEAT ADVISORY from 11 AM this morning to 9 PM CDT this evening for KSZ025-057-060-102. EXCESSIVE HEAT WARNING from 11 AM this morning to 9 PM CDT this evening for KSZ103>105. MO...HEAT ADVISORY from 11 AM this morning to 9 PM CDT this evening for MOZ011>014-020>023-030-031-038-039-043>046-053-054. EXCESSIVE HEAT WARNING from 11 AM this morning to 9 PM CDT this evening for MOZ028-029-037. && $$ DISCUSSION...Leighton AVIATION...Blair
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
305 AM CDT SAT AUG 8 2015 .SHORT TERM...(Today through Sunday) Issued at 305 AM CDT SAT AUG 08 2015 First concern is ongoing convection across northern Kansas. Successive runs of the HRRR dissipates this area before it gets into the forecast area as does the RAP. Given expanding ridging would expect it to dissipate as it gets closer and stay north of the area. Will monitor radar trends and update as needed. For now will keep dry forecast for the morning hours. Attention then turns to the aforementioned expanding ridge across the area. This ridge will dominate the weather through Sunday with increasing heat and humidity. Heat advisory already in effect for much of the area from this afternoon through Sunday evening. Expect afternoon heat indicies in the 100 to 110 degree range both days. Biggest question will be the need to expand the advisory further eastward. Eastern Ozarks best chance to hit advisory criteria would be Sunday afternoon. Will allow day shift to evaluate it further. .LONG TERM...(Sunday night through Friday) Issued at 305 AM CDT SAT AUG 08 2015 Upper ridge retracts westward Sunday night and Monday allowing for a surface frontal boundary to slip southward into the area. This will bring our next chance for rain. Medium range models showing the better chances across central Missouri from late Sunday night into Monday morning. Pattern then dominated by a northwest flow regime with a surface high building southward into the area. This will result in quiet and dry weather with near to slightly below normal temperatures. && .AVIATION...(For the 06Z TAFS through 06Z Saturday Night) Issued at 1133 PM CDT FRI AUG 07 2015 Generally VFR conditions are expected at area terminals tonight through Saturday. The exception may be patchy light fog late tonight into early Friday morning which could lead to a brief interval of MVFR visibilities. Otherwise a light southerly wind will develop Saturday. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...HEAT ADVISORY from Noon today to 10 PM CDT Sunday for MOZ055-056- 066>069-077>081-088>096-101>105. KS...HEAT ADVISORY from Noon today to 10 PM CDT Sunday for KSZ073-097- 101. && $$ SHORT TERM...Raberding LONG TERM...Raberding AVIATION...Foster
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
256 AM CDT SAT AUG 8 2015 .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 255 AM CDT SAT AUG 8 2015 MCS OVER EASTERN NEBRASKA AND NORTH CENTRAL KANSAS IS FORECAST TO DECAY AS IT MOVES EAST TODAY. HAVE INTRODUCED SOME SLIGHT CHANCE POPS INTO THE FORECAST FOR TODAY ALONG AND NORTH OF I-70 AS LATEST RUNS OF HRRR SUGGEST TAIL END OF THE DECAYING SYSTEM COULD BRING SOME ISOLATED TO SCATTERED SHOWERS/STORMS ACROSS THE AREA THIS MORNING AND EARLY AFTERNOON. TEMPERATURES ARE GOING TO BE TRICKY WITH CONVECTIVE DEBRIS CLOUD COVER. HAVE DECIDED TO STICK WITH A HEALTHY BLEND OF THE LATEST GUIDANCE AND LET THE DAY SHIFT ADJUST IF CLOUD COVER AND PRECIPITATION LIMIT INSOLATION. CVKING .LONG TERM: (TONIGHT THROUGH FRIDAY) ISSUED AT 255 AM CDT SAT AUG 8 2015 THUNDERSTORMS ARE EXPECTED TO REDEVELOP THIS AFTERNOON AND EVENING TO THE NORTHWEST OF THE CWA AND GROW UPSCALE INTO ANOTHER MCS. THE TRACK OF THE SYSTEM IS STILL FORECAST TO JUST GRAZE THE NORTHERN CWA TONIGHT...POSSIBLY PROPOGATING SOUTHEAST INTO SOUTH CENTRAL ILLINOIS ON SUNDAY MORNING. SEVERE WEATHER THREAT ASSOCIATED WITH THIS SYSTEM IS DAMAGING WIND GUSTS IN EXCESS OF 60 MPH. ANOTHER STRUGGLE BETWEEN CONVECTIVE DEBRIS AND VERY WARM TEMPERATURES ALOFT RESULTS IN A LOW CONFIDENCE TEMPERATURE FORECAST FOR SUNDAY. POTENTIAL IS CERTAINLY THERE FOR A HOT AND STEAMY DAY WITH HEAT INDEX VALUES ABOVE 105 DEGREES IN THE AFTERNOON AND EVENING. WILL CONTINUE TO HIGHLIGHT IN THE HWO AND ALLOW DAYSHIFT ANOTHER SET OF MODEL RUNS BEFORE ISSUING ANY HEADLINES FOR HEAT ON SUNDAY. CONVECTION SHOULD REDEVELOP AGAIN SUNDAY AFTERNOON AND CONTINUE INTO THE NIGHT...PROBABLY INITIALLY ON THE OUTFLOW BOUNDARY FROM THE MORNING MCS AND THEN THE COLD FRONT SETTLING SOUTH ACROSS THE REGION. HAVE KEPT HIGH CHANCE POPS BUT COULD SEE LATER SHIFTS INCREASING TO LIKELY. REMAINDER OF THE FORECAST FEATURES SLIGHTLY BELOW NORMAL TEMPERATURES AND DRY CONDITIONS AS NORTH TO NORTHWEST FLOW CONTINUES TO DELIVER HIGH PRESSURE TO THE REGION. CVKING && .AVIATION: (FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1055 PM CDT FRI AUG 7 2015 WEAKENING COLD FRONT EXTENDING FROM A SURFACE LOW OVER WI SW INTO NORTHEAST MO WILL CONTINUE MOVING SOUTHEASTWARD LATE TONIGHT AND DISSIPATE. COULD NOT RULE OUT AN ISOLATED SHOWER/STORM ALONG THIS WEAK FRONT...BUT FOR NOW WILL LEAVE UIN TAF DRY. HIGH LEVEL CLOUDINESS WILL STREAM EASTWARD FROM THE PLAINS LATE TONIGHT... MAINLY FROM CONVECTION ACROSS KANSAS AND NEBRASKA. WITH LIGHT SURFACE WINDS AND RELATIVELY HIGH SURFACE DEW POINTS...THERE MAY BE SOME FOG LATE TONIGHT/EARLY SATURDAY MORNING...ALTHOUGH THE NAM MOS GUIDANCE APPEARS OVERDONE ON ITS STRATUS/FOG FORECAST AT THE TAF SITES. SOUTHEASTERLY SURFACE WINDS ON SATURDAY WITH SCATTERED DIURNAL CUMULUS ALONG WITH HIGH LEVEL CLOUDS AGAIN. SPECIFICS FOR KSTL: SOME HIGH LEVEL CLOUDS FOR LATE TONIGHT. LIGHT E-SELY SURFACE WIND LATE TONIGHT WILL STRENGTHEN TO AROUND 7-8 KNOTS SATURDAY AFTERNOON. SCATTERED DIURNAL CUMULUS CLOUDS WILL DEVELOP AGAIN FOR LATE SATURDAY MORNING AND AFTERNOON. GKS && .PRELIMINARY POINT TEMPS/POPS: SAINT LOUIS 91 76 95 75 / 10 20 30 40 QUINCY 87 71 89 70 / 20 60 40 20 COLUMBIA 90 75 94 72 / 10 20 20 40 JEFFERSON CITY 91 76 96 74 / 10 20 20 40 SALEM 87 72 91 73 / 10 10 30 40 FARMINGTON 88 72 94 74 / 10 10 20 40 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
614 PM CDT SUN AUG 9 2015 .SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 333 PM CDT SUN AUG 9 2015 CHANCE FOR THUNDERSTORMS AND THEIR SEVERITY TONIGHT ARE THE PRIMARY FORECAST CONCERNS. THUNDERSTORMS WERE FIRING AT MID AFTERNOON ALONG A WEAK SURFACE BOUNDARY STRETCHING FROM SOUTHEAST SOUTH DAKOTA INTO WESTERN NEBRASKA. THESE STORMS HAVE PLENTY OF INSTABILITY AND SHEAR TO FEED ON...SOME 2500 J/KG OF MLCAPE AND 40KT OF EFFECTIVE BULK SHEAR...AS PER LATEST RAP OBJECTIVE ANALYSIS. ALREADY GETTING REPORTS OF SEVERE HAIL JUST WEST OF OUR AREA WHERE VIGOROUS UPDRAFTS WERE SEEN. AND FREEZING LEVELS ARE QUITE A BIT LOWER THAN LAST EVENING. SO A CONTINUED HAIL THREAT IS CERTAINLY EXPECTED...WITH MODEST MICROBURST POTENTIAL ALSO NOTED ON RAP PROGS. PERHAPS A BIGGER SHOW WITH POTENTIALLY MORE WIDESPREAD SEVERE LATER THIS EVENING IS POSSIBLE. MID LEVEL SHORTWAVE DIVING INTO WESTERN SOUTH DAKOTA WILL CONTINUE SOUTHEAST THIS EVENING...PUSHING A COLD FRONT ALONG WITH IT. SHEAR PROFILES SHOULD ACTUALLY INCREASE IN MAGNITUDE GIVEN MID LEVEL SPEED MAX TIED TO WAVE. SHEAR VECTORS ARE LINING UP NEARLY PARALLEL WITH EXPECTED FRONTAL/CONVECTIVE LINE...SUPPORTING MORE OF A LINEAR STORM MODE. WIND FIELDS...PREDICTED DOWNDRAFT CAPE AND LAYER THETA-E DIFFERENCES APPROACHING 30 ALL SUGGEST SEVERE WIND POTENTIAL AS LINE RACES INTO EASTERN NEBRASKA. SEVERAL MESOSCALE HI-RES MODELS ARE OFFERING VARIED OPINIONS AROUND THIS LINE OF THINKING...SO WILL HIT EVENING THUNDER CHANCES PRETTY HARD. EXPECT STORMS TO SLOWLY DIE OFF LATER THIS EVENING AND OVERNIGHT AS THEY APPROACH INTERSTATE 80 AND BEYOND...HOWEVER SEVERE THREAT APPEARS TO LINGER FOR SOME TIME AFTER DARK. BY MONDAY MORNING LINGERING STORMS SHOULD BE EXITING OUR SOUTHEAST CWA. HOWEVER WEAK IMPULSE IN MID LEVEL FLOW COULD TAP WANING INSTABILITY IN THE MID AFTERNOON TO PRODUCE A STORM OR TWO IN SOUTHWEST IOWA. THEN NORTHERLY SURFACE FLOW UNDER HIGH PRESSURE WILL FORETELL A RELATIVELY DRY PERIOD OVER THE NEXT COUPLE OF DAYS. HIGHS BOTH TUESDAY AND WEDNESDAY WILL GRADUALLY INCREASE INTO THE LOWER AND MIDDLE 80S UNDER PLENTY OF SUNSHINE. AND DEW POINTS SHOULD BE LOWER ON TUESDAY BEFORE BEGINNING TO RETURN WEDNESDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 333 PM CDT SUN AUG 9 2015 OUR RELATIVELY QUIET WEATHER PATTERN IS EXPECTED TO CONTINUE THROUGH THE REST OF THE WEEK. MID LEVEL HIGH PRESSURE RIDGE IS FORECAST BY BOTH ECMWF AND GFS TO BUILD FROM THE SOUTHERN PLAINS INTO THE NORTHERN ROCKIES...AND EXPAND A BIT TO THE EAST. THIS WILL TAKE MAIN STORM TRACK NORTH AND EAST OF OUR AREA...AND ALLOW FOR WARMER TEMPERATURES BOTH AT THE SURFACE AND ALOFT. WILL MAINTAIN OUR DRY FORECAST UNTIL MAYBE SATURDAY NIGHT OR SUNDAY WHEN RIDGE IS FORECAST TO BEGIN TO BREAK DOWN. HIGHS MAINLY IN THE UPPER 80S AND LOWER 90S SHOULD PREVAIL. && .AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 612 PM CDT SUN AUG 9 2015 BAND OF THUNDERSTORMS WILL AFFECT KOFK FOR THE FIRST FEW HOURS OF THE TAF PERIOD. THEN ANOTHER LINE OF STORMS MOVING SOUTHEAST WILL ENTER EASTERN NEBRASKA...AFFECTING KOFK BETWEEN 04Z AND 06Z...THEN KLNK AND KOMA BETWEEN 06Z AND 09Z. MVFR CIGS/VSBYS WILL BE COMMON IN STORMS...BUT BRIEFLY LOWER CONDITIONS ARE CERTAINLY POSSIBLE. STRONG WINDS MAY ACCOMPANY STORMS AS WELL. BEHIND THIS SECOND BAND OF THUNDERSTORMS...AREAS OF MVFR FOG ARE LIKELY THROUGH 14Z...WITH A SMALL CHANCE OF MVFR/IFR CIGS AS WELL. THEN NORTH WINDS UNDER 12KT AND VFR CONDITIONS ARE FORECAST BEYOND 14Z AT ALL SITES. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...DERGAN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
315 PM CDT SAT AUG 8 2015 .SHORT TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 315 PM CDT SAT AUG 8 2015 NO BIG CHANGES FROM PREVIOUS THINKING...MAIN CONCERN IS POTENTIAL FOR SEVERE WEATHER AND HEAVY RAIN. THE SEVERE THREAT WOULD MAINLY BE PRIOR TO 06Z TONIGHT AND THEN ALSO LATE SUN AFTN/SUN EVENING. HEAVY RAIN THREAT IS PRIOR TO ABOUT 08Z TONIGHT...AND MAINLY IN SWRN IA. JET PATTERN AT 12Z SHOWED 300 MB WINDS OF 50 TO 80 KNOTS FROM SRN CA INTO SD/ND/MN. A 500 MB LOW WAS OVER SRN ID AT 12Z BUT WATER VAPOR IMAGERY/RECENT RUC MODEL INITILIZATIONS SHOWED IT HAD MOVED TO NEAR THE ID/MT/WY BORDER AREA AS OF EARLY THIS AFTN. THIS WILL CONTINUE TO TRACK SLOWLY NEWD/EWD TONIGHT. THE 19Z KOAX SOUNDING SHOWED THAT THE MID LEVELS HAD WARMED A BIT SINCE 12Z. OUR 12Z 700 MB TEMP WAS 7.6 C BUT HAD INCREASED TO 10.7 C AS OF 19Z. 19Z SPC MESOANALYSIS SHOWED THAT THERE WAS STILL QUITE A BIT OF LOWEST 100 MB CONVECTIVE INHIBITION (MLCIN) AND MOST OF THE AREA WAS NOT OVERLY UNSTABLE. HIGHEST MLCAPE WAS NEAR THE KS BORDER... AROUND 2000 J/KG. CAP WAS WEAKEST FROM SWRN KS INTO PARTS OF CNTRL KS AS OF MID AFTN...NEAR AND AHEAD OF SFC LOW PRES CENTER. THERE REMAINS A CONDITIONAL THREAT OF SEVERE WEATHER FOR MOST OF THE AREA. 0-6 KM SHEAR IS EXPECTED TO BE ADEQUATE FOR ROTATING STORMS...BUT THERE IS SOME UNCERTAINTY AS TO WHEN AND WHERE STRONG/SEVERE STORMS MAY FORM. THE MODELS OFFER VARYING SOLUTIONS. ONE THING WE SAY IS THAT IT DOES APPEAR THAT BEST FOCUS WILL SHIFT TO IA AND NRN MO LATER TONIGHT WITH A 30-50 KNOT LOW LEVEL JET. LOWS SHOULD RANGE FROM MID 60S N TO AROUND 70 S. WILL KEEP STORM CHANCES OVERNIGHT AND SUNDAY MORNING FOR AT LEAST PARTS OF THE FCST AREA. BETTER POTENTIAL THOUGH APPEARS TO BE LATER IN THE DAY ACRS OUR NRN ZONES...AS A FRONTAL SYSTEM DROPS INTO THE AREA. KEPT SOME LOW POPS FOR LATE SUNDAY NIGHT AND MONDAY BUT NOT IMPRESSED WITH RAIN POTENTIAL IN THOSE PERIODS FOR NOW... ESPECIALLY MONDAY WHEN SURFACE RIDGE AXIS WILL BE BUILDING DOWN ACROSS THE REGION. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 315 PM CDT SAT AUG 8 2015 PCPN CHANCES LOOK TO BE 14 PERCENT OR LESS FROM MONDAY NIGHT ONWARD...SO FCST TEXT WILL NOT HAVE ANY MENTION OF TSTMS IN THOSE PERIODS. 500 MB RIDGE IS EXPECTED TO BUILD W AND N FROM OK AND TX MUCH OF THE WEEK...THEN FLATTEN A BIT BY NEXT WEEKEND AS TROUGH MOVES EAST FROM THE PACIFIC NW AND NRN ROCKIES. LEFT A BLEND OF GFS AND ECMWF TEMPS IN THE EXTENDED PERIOD...BUT HIGHS MAY END UP BEING A BIT WARMER THAN THAT. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1217 PM CDT SAT AUG 8 2015 GENERALLY VFR CONDITIONS ARE EXPECTED INTO THE OVERNIGHT PERIOD. WE WILL SEE A BKN MID AND HIGH LEVEL DECK THROUGH THE DAY TODAY AND LIGHT SOUTHEAST WINDS. THERE IS SOME THREAT OF SHRA AT KLNK/KOMA LATE THIS AFTN INTO THE EARLY EVENING AND WILL INCLUDE A TEMPO GROUP FOR THESE TAFS. OVERNIGHT WE EXPECT SOME IFR CIGS DEVELOP FOR KOMA/KOFK...WHICH MAY GET CLOSE TO KLNK BY SUN MRNG. WE WILL ALSO SEE SOME MVFR VSBY OVERNIGHT AS WELL. CONDITIONS SHOULD IMPROVE BY MID TO LATE MORNING SUNDAY. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...MILLER LONG TERM...MILLER AVIATION...BOUSTEAD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1148 PM CDT FRI AUG 7 2015 .SHORT TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 315 PM CDT FRI AUG 7 2015 THE PRIMARY FORECAST CONCERNS ARE IN REGARDS TO THE POTENTIAL FOR TSTMS/RAIN LATER TONIGHT AND INTO SATURDAY...PLUS THE CHANCE OF SEVERE WEATHER SATURDAY. MAIN FEATURES FROM THE UPPER AIR MAPS THIS MORNING INCLUDED THE FOLLOWING. AT 300 MB A 75 KT JET STREAK WAS OVER SRN CA PUNCHING TO THE E/NE. THE 500 MB PATTERN IN GENERAL SHOWED TROUGHING ACROSS THE W AND E COASTS AND A RIDGE CENTERED OVER TX/OK. CLOSED LOWS WERE NOTED OVER SRN ALTA AND OVER CNTRL CA. 12 HOUR HEIGHT FALLS WERE AROUND 50 METERS WITH THE CA SYSTEM...WHICH CONTINUED TO LIFT INTO NV ACCORDING TO RECENT WATER VAPOR IMAGERY AND RECENT RUC MODEL INITIALIZATIONS. A THERMAL RIDGE AT 700 MB EXTENDED FROM THE TX PNHDL UP INTO CO. FAIRLY DECENT MOISTURE WAS NOTED AT 700 MB FROM AZ INTO SRN NV WITH DEWPOINTS 5-8 DEGREES C. THE KOAX SOUNDING THIS MORNING HAD ABOUT 0.94 INCHES OF PRECIPITABLE WATER (PW). THIS WILL BE INCREASING OVER THE AREA TONIGHT. 12Z GFS SHOWED VALUES APPROACHING 2 INCHES FOR MOST OF OUR AREA BY 12Z SAT AND NEAR 2.25 INCHES BY 00Z SUN. THE 12Z NAM WAS A BIT HIGHER AND MIGHT HAVE BEEN A BIT OVERDONE. PREVIOUS FORECAST TREND WAS FOR INCREASING POPS OVERNIGHT AND THAT STILL SEEMS ON TRACK. WILL KEEP HIGHEST POPS PRIOR TO 12Z SAT OVER ERN NE...SHIFTING HIGHEST NUMBERS TO NERN NE BY LATE MORNING. MID LEVEL TEMPS ARE EXPECTED TO WARM SAT MORNING OVER THE SRN HALF OF THE FCST AREA...SO SHIFTED HIGHEST POPS TO OUR WRN IA ZONES FOR THE LATE AFTN AND EVENING. CONVECTIVE EVOLUTION AFTER THE MORNING STORMS IS UNCERTAIN...BUT SHEAR PARAMETERS COULD BE FAVORABLE FOR SOME SUPERCELLS IN THE AFTN AND EVENING. BEST SHOT FOR HEAVY RAIN WILL BE ACROSS IOWA SATURDAY NIGHT. STORM CHANCES SHOULD DIMINISH AFTER MIDNIGHT SATURDAY NIGHT...AND SUNDAY RAIN CHANCES LOOK FAIRLY LOW. MID LEVEL RIDGE AXIS WILL START TO BUILD FROM TX UP INTO SASK MONDAY WITH DECENT TROUGHING OVER THE GREAT LAKES REGION. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 315 PM CDT FRI AUG 7 2015 A STRONG MID TROPOSPHERIC RIDGE WILL BE BUILDING AT THE START OF THIS PERIOD OVER MID AMERICA. BY LATE WEEK...THE CENTER OF THE ANTICYCLONE THAT STARTED OUT OVER TX/OK SHOULD RETROGRADE BACK INTO NM AND CO. THIS PATTERN GENERALLY PRODUCES WARMER THAN NORMAL TEMPERATURES (ESPECIALLY HIGHS) AND BELOW NORMAL PCPN. SO...BUMPED UP HIGHS A BIT COMPARED TO A GFS/ECMWF BLEND. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1143 PM CDT FRI AUG 7 2015 VFR CONDITIONS STILL PREVAIL AT ALL SITES...BUT SHRA AND POSSIBLY TSRA WILL AFFECT SITES TONIGHT AND INTO THE EARLY MORNING HOURS. HAVE INCLUDED PREVAILING SHRA/TEMPO THUNDER AT ALL SITES...WITH ACTIVITY WANING BY MID-MORNING. WITH CONSIDERABLE UNCERTAINTY REGARDING CONVECTIVE EVOLUTION LATER TODAY/THIS EVENING...HAVE OPTED TO KEEP MENTION OUT OF TAFS FOR NOW. POTENTIAL DOES EXIST FOR SHRA/TSRA AT SITES FROM LATE AFTERNOON THROUGH EVENING...WITH A SOMEWHAT HIGHER RISK AT KOMA/KLNK THAN KOFK. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...MILLER LONG TERM...MILLER AVIATION...MAYES
AREA FORECAST DISCUSSION
NWS ELKO NV
536 PM PDT SUN AUG 9 2015 .SYNOPSIS...TEMPERATURES WILL REMAIN TYPICAL FOR AUGUST ACROSS NEVADA THIS WEEK. MONSOON MOISTURE WILL RETURN TO EASTERN NEVADA BY MIDWEEK...INCREASING THE COVERAGE OF SHOWERS AND THUNDERSTORMS. && .UPDATE...RADAR INDICATES ISOLATED SHOWERS CONTINUING TO REGENERATE ACROSS NORTHERN NEVADA. INCREASED POP/WX/SKY GRIDS FOR THE NEXT SEVERAL HOURS. SHOWER ACTIVITY WILL REMAIN ISOLATED BEFORE DISSIPATING AFTER SUNSET. TURNER && .PREV DISCUSSION... /ISSUED AT 318 PM / SYNOPSIS...TEMPERATURES RUNNING SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NORTHERN NEVADA THIS AFTERNOON. THERE IS A CHANCE FOR MONSOON MOISTURE MIDWEEK...FOLLOWED BY ANOTHER PACIFIC STORM NEXT WEEKEND. SHORT TERM...TODAY THROUGH TUESDAY. THE HRRR IS PRETTY CONVECTIVE NORTH OF INTERSTATE 80 THIS AFTERNOON AND INTO THE EVENING...WHICH GAINS SOME SUPPORT FROM THE LATEST VISIBLE IMAGE ON SATELLITE. HOWEVER...WITH REGARD TO QPF...THE NAM AND THE HRRR MAY BE OVER DOING IT A BIT...ALTHOUGH THE PLACEMENT OF THE CONVECTION IS VERY FEASIBLE. LIGHTNING STRIKES HAVE BEEN OBSERVED OVER PORTIONS OF ELKO COUNTY NEAR THE IDAHO BORDER. THE HRRR HAS THE CONVECTION BASICALLY BEING SHUNTED AT 2Z...AND BY 5Z THE LKN CWA IS TSRA FREE. TOMORROW THE GFS BRINGS A SLUG OF MOISTURE BY 18Z AND THE NAM HAS NOTHING AT 18Z...AND A FRACTION OF THE QPF SHIELD BY 00Z WITH AN OFF SET PLACEMENT. THE POPS IN THIS FORECAST PACKAGE REPRESENTS A CONSALL MODEL BLEND APPROACH...BUT NOT THE BEST CONFIDENCE. TUESDAY...MORE OF THE SAME CONSALL BLENDING...WITH THE QPF ON THE EASTERN PORTION OF THE CWA...WHICH ACCOUNTS FOR THE PROGRESSIVE NATURE OF THE INCOMING PACIFIC LOW. LONG TERM...TUESDAY NIGHT THROUGH SUNDAY. A NORTHEAST PACIFIC LOW MOVES ASHORE AND STRUGGLES TO ENTER THE INTERIOR WEST AS IT MOVES AGAINST THE FOUR CORNERS RIDGE. THIS CREATES MOSTLY DRY FLOW INTO THE GREAT BASIN...BUT AT TIMES WEAKNESSES IN THE RIDGE-TROUGH BOUNDARY WILL ALLOW FOR LIMITED MOISTURE INTO THE REGION. HENCE...PERIODS OF ISOLATED THUNDERSTORMS OF THE HYBRID VARIETY THROUGH ABOUT FRIDAY. NEXT WEEKEND LOOKS DRY. TEMPS NEAR NORMAL. ONE THING THOUGH...WINDS INCREASE WEDNESDAY AND THURSDAY WITH LOWER RH VALUES FOR A POSSIBLE FIRE WEATHER SITUATION. STAY TUNED FOR WHEN THIS TIME COMES INTO THE SHORT TERM PERIOD. AVIATION...VFR CONDITIONS ARE EXPECTED AT KWMC KEKO KELY AND KTPH THROUGH MONDAY AFTERNOON. ISOLATED THUNDERSTORMS ARE POSSIBLE OVER NORTHERN NEVADA EARLY SUNDAY EVENING AND MONDAY AFTERNOON. MOST WILL STAY CLEAR OF KWMC AND KEKO. FIRE WEATHER...VIRGA...ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NORTHERN NEVADA THIS AFTERNOON. SO FAR FWZ 470...HAS GOTTEN THE LIONS SHARE OF THE LIGHTNING AS CONVECTION HAS BEGUN TO PERCOLATE OVER NORTHERN NV. THERE IS A CHANCE FOR MONSOON MOISTURE MIDWEEK...FOLLOWED BY A WIND EVENT THURSDAY AND FRIDAY. THE MODELS ARE FLIPPING A BIT AND NOT HANDLING THE MONSOON SURGE FOLLOWED BY A ANOTHER PACNW STORM WELL. THIS ASSESSMENT IS BACKED BY THE NCEP RMOP WHICH IS IN MARKEDLY LESS CONFIDENT TERRITORY BY F72...WITH REGARD TO THE ENSEMBLE MEAN FORECAST AT 500 MB. && .LKN WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS ELKO NV
325 PM PDT SAT AUG 8 2015 .SYNOPSIS...REMNANT MOISTURE WILL FUEL ISOLATED TO SCATTERED THUNDERSTORMS THIS AFTERNOON. DRIER CONDITIONS ANTICIPATED SUNDAY AND MONDAY. THE MONSOON WILL RETURN OVER EASTERN NEVADA MIDWEEK. && .SHORT TERM...TODAY THROUGH MONDAY. THE LONGWAVE PATTERN FEATURES AN H5 LOW OVER IDAHO...AND A CLOSED LOW UPSTREAM OFF THE COAST OF BRITISH COLUMBIA...AND A DOME OF HIGH PRESSURE OVER TEXAS. SUFFICIENT LI`S AND CAPES FOR CONVECTION INTO THE EVENING...AND BOTH THE HRRR AND THE 18Z NAM PINGING INTO TSRA FOR THE LKN CWA. THE CONVECTIVE TEMP FOR 21Z IS 77F FOR KEKO WITH A PW OF .73 OF AN INCH. THE 18Z RUN OF THE GFS IS MORE STABLE...BUT...POPS WERE HEDGED TOWARDS A NAM/HRRR COMPROMISE AND REALTIME OBSERVATIONS. AS TIME ELAPSES...EXPECT THE PWS TO DRY OUT...AND EXPECT AFTERNOON TEMPERATURES TO REMAIN SLIGHTLY BELOW NORMAL FOR THE MONTH OF AUGUST. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY. THE LONG TERM MODELS ARE IN MUCH BETTER AGREEMENT TODAY THAN PREVIOUSLY. EVEN DEPICTING THE SLUG OF MOISTURE COMING UP OUT OF THE GULF OF CALI WED INTO THU IS NICELY DONE. THIS IS IN AGREEMENT WITH PREVIOUS IDEAS...TOO. OVERALL...THERE IS NOT MUCH CHANGE TO THE PREVIOUS FORECAST PACKAGE OTHER THAN SOME TWEAKS TO MAKE SURE WE AGREE WITH SURROUNDING OFFICES` FORECASTS. TEMPS WILL BE NEAR NORMAL WITH A LITTLE COOL DOWN DUE TO CLOUDS. MOSTLY DRY PERIOD WITH INCREASED SOUTHWEST FLOW FROM PACIFIC LOW COMING IN FIRST PART. ISOLATED MAINLY SOLAR DRIVEN TERRAIN ENHANCED THUNDERSTORMS COULD OCCUR LATE MONDAY INTO TUESDAY OVER WHITE PINE COUNTY AND THE JARBIDGE AREA. LOW AND CENTRAL NOAM RIDGE WORK IN TANDEM WEDNESDAY TO BRING SOME LIMITED RH INTO EASTERN NEVADA SO HAVE KEPT LOW POP MOSTLY THERE WED AND THUR. WITH INCREASE OF CONVECTION WEDNESDAY AND THURSDAY AND TIGHTENING OF GRADIENT ALOFT MIXING WINDS DOWN...COULD SEE SOME FIRE WX CONCERNS MID TO LATE WEEK. FRIDAY AND SATURDAY...DRIER AS UPPER LOW OPENS UP AND MOVES NORTHEAST INTO THE NORTHERN ROCKIES. && .AVIATION...REMNANT MOISTURE AND INSTABILITY HAS ALLOWED FOR AFTERNOON CUMULUS DEVELOPMENT. CHANCE OF SHOWERS/STORMS, ALTHOUGH SLIGHT, POSSIBLE THROUGH THE EVENING FOR KEKO, KWMC, AND KELY WITH THE BEST POTENTIAL IN KEKO. THIS ACTIVITY SHOULD DISSIPATE AFTER SUNDOWN AND DRY AND VFR CONDITIONS EXPECTED FOR SUN. && .FIRE WEATHER...MORE LIGHTNING POSSIBLE THIS AFTERNOON...WITH THE BEST LIGHTNING SHOW OVER 467 TODAY SO FAR. EXPECTING A DRYING TREND...BUT BY MIDWEEK MODELS HINT AT ANOTHER MONSOON SURGE. && .LKN WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 97/98/98/97
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1038 AM EDT SAT AUG 8 2015 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE OUR WEATHER THROUGH SUNDAY BRINGING MAINLY DRY CONDITIONS AND COMFORTABLE TEMPERATURES. THE NEXT SIGNIFICANT CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE MONDAY INTO TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... VISIBLE SATELLITE IMAGERY SHOWS A MID-HI CLOUD SHIELD MOVING EASTWARD ASSOCIATED WITH A SHORT WAVE OVER THE GREAT LAKES. THIS WAVE WAS SEEN WELL IN THE WATER VAPOR IMAGERY. THIS FEATURE HAS SOME LIGHT PRECIP OR EVEN SOME VIRGA ASSOCIATED WITH IT SINCE IT WAS MOISTURE STARVED. THIS WAVE WILL SPREAD MID-HI CLDS ACRS THE REGION THIS AFTERNOON INTO THE EVENING. LOOKING AT KBUF RADAR THE RADAR ECHOES WERE HAVING A DIFFICULT TIME PENETRATING INTO WRN NY SUGGESTING ACVTY WAS DRYING UP. SO HAVE OPTED TO KEEP POPS LESS THAN 15 PCT THRU AFTERNOON IN NY AND NC PA SIMILAR TO PREVIOUS SHIFT. AT BEST MAYBE SOME AREA GETS A SPRINKLE OR TWO FROM THIS BUT I FEEL THAT IS A LONG SHOT. SOUTH OF THIS WAVE IN PA THERE WAS MAINLY CLEAR SKIES AND STRG INSOLATION AND THE LATEST NAM WAS DEVELOPING ISLD CONVECTION OVER THE HIGHER TERRAIN OF THE CATSKILLS...POCONOS AND OTHER HIGHLANDS OF NRN PA. THE 12Z NAM HAS SFC BASED CAPES BETWEEN 500 AND 1000 J/KG IN THESE AREAS. LOOKING AT THE LL MOISTURE FIELDS IN THE NAM MODEL VS REALITY...IT APPEARS THE NAM IS A OVERDONE HERE. THIS WUD BE THE ONLY OTHER CHC FOR ANY PRECIP IN THE REGION. THE LATEST HRRR MODEL SHOWS NO RADAR ECHOES IN THE BGM FORECAST AREA THRU THIS EVENING. THE LATEST RAP (WHICH DRYS THE BNDRY LAYER WAY TOO MUCH) BRINGS SOME SPRINKLES TO THE FINGER LAKES THIS EVENING WITH THE ABV MENTIONED WAVE. BUT GIVEN THE DRIER BNDRY LAYER IN THIS MODEL NO CONVECTION POPS IN NE PA OR CATSKILLS. THE RAPS SFC DWPTS DROP INTO THE 40S WHICH IS UNREALISTIC. FOR TONIGHT...LEFT PREV SHIFTS SLGHT CHC FOR SHRA IN OUR SRN AND SW ZONES WHICH IS FROM STUEBEN CO NY TO NE PA FOR NOW AS WE WAIT FOR THE ALL THE NEW 12Z GUIDC. IF ANYTHING MIGHT HAVE TO PUT SLGHT CHC FARTHER N TO ACCOUNT FOR THE GREAT LAKES SHORT WAVE WHICH MOVES ACRS THE REGION. IN ANY EVENT...WE ARE NOT TALKING ABT MUCH SENSIBLE WX OTHER THAN MAINLY CLDY SKIES TONIGHT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 4 AM UPDATE... LIMITED INSTABILITY AND MOISTURE...WITH ONLY WEAK SHORTWAVES TRAVERSING WNW-ESE FLOW ALOFT...WILL KEEP SHOWER CHANCES /AND COVERAGE/ SLIGHT AT BEST SUNDAY-SUNDAY NIGHT. HOWEVER...FOR MONDAY INTO ESPECIALLY MONDAY NIGHT...MODEL CONSENSUS CONTINUES TO SHOW AMPLIFYING TROUGH DIGGING INTO THE GREAT LAKES REGION MONDAY- MONDAY NIGHT...WITH INCREASING MOISTURE AND INSTABILITY AHEAD OF IT. AT THE SAME TIME...A SURFACE LOW IS DEPICTED AS TRACKING INTO OUR REGION MONDAY NIGHT. THE MODELS DIFFER IN SOME DETAILS...SUCH AS HIGHER PRECIPITABLE WATER VALUES IN THE NAM...AND A SLOWER EVOLUTION IN THE ECMWF. BUT FOR THE GENERAL IDEA...MODELS ARE IN FAIRLY GOOD AGREEMENT. WE CONTINUE WITH A FORECAST OF INCREASING SHOWER CHANCES MONDAY...PEAKING LATE MONDAY THROUGH ESPECIALLY MONDAY NIGHT WHEN SHOWERS WILL BE ESPECIALLY LIKELY. WITH INSTABILITY ALSO BECOMING PRESENT...THERE WILL BE A CHANCE OF THUNDERSTORMS AS WELL...HOWEVER MID LEVEL LAPSE RATES AND SHEAR WILL BOTH BE ON THE LOW SIDE SO SEVERE PROSPECTS ARE MINIMAL. THOUGH PRECIPITABLE WATER VALUES WILL NOT BE VERY HIGH...THEY ARE FORECAST TO GET TO AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL...WHICH COMBINED WITH SLOW SYSTEM PROGRESSION COULD YIELD LOCALIZED HEAVY RAINFALL /PERHAPS A FEW LOCATIONS GETTING MORE THAN AN INCH/. OVERALL EXCESSIVE RAINFALL POTENTIAL DOES NOT APPEAR VERY SIGNIFICANT YET BUT THIS WILL HAVE TO BE MONITORED. && .LONG TERM /TUESDAY THROUGH FRIDAY/... FOLLOWED CLOSE TO WPC GUIDANCE. OVERALL, UNSETTLED TO START THE PERIOD WITH AN IMPROVING TREND LATER IN THE WEEK. UPPER LEVEL TROUGH LINGERS OVER THE AREA MUCH OF THE WEEK. THE RESULT WILL BE ABUNDANT CLOUDINESS WITH CONTINUING SCATTERED SHOWERS AND THE CHANCE OF THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON HOURS DUE TO DIURNAL HEATING. EXPECT THIS TO OCCUR ON TUESDAY WITH SHOWERS AND ANY STORMS DYING DOWN AFTER SUNSET AND THEN POPPING UP AGAIN WEDNESDAY AFTERNOON. BY THURSDAY, AS THE DEEPER MOISTURE MOVES AWAY EXPECT MORE IN THE WAY OF SOME SUNSHINE WITH ONLY A SLIGHT CHANCE OF SHOWERS FOLLOWED BY DRY WEATHER FOR NEXT FRIDAY. THE UPPER LOW AND CLOUDINESS WILL KEEP TEMPS RUNNING COOLER THAN AVERAGE FOR MOST OF THE LONG RANGE WITH HIGHS MAINLY IN THE 70S AND LOWS IN THE 50S. BY NEXT FRIDAY, TEMPS RETURN TO SEASONAL. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... DRY WX CONTS OVER THE AREA BRINGING VFR CONDS. XCPTN CONTS TO BE LATE AT NGT WHEN LGT WINDS ALLOW VLY FOG TO DVLP. BRIEF RESTRICTIONS TO IFR PSBL AT ELM LATE NGT...MVFR ELSEWHERE. LGT WLY FLOW...ESP DURING THE DAY WITH MIXING...WILL CONT. DRAINAGE WINDS TAKEOVER AT NGT. .OUTLOOK... SUN... EXCEPT FOR POSSIBLE EARLY MORNING RESTRICTIONS DUE TO FOG (MAINLY KELM)...VFR IS EXPECTED. MON-TUE... RESTRICTIONS POSSIBLE FROM SHOWERS/THUNDERSTORMS. WED...VFR...BUT POTENTIAL BRIEF RESTRICTIONS IN SHRA. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJN/MDP NEAR TERM...DJN SHORT TERM...MDP LONG TERM...PCF AVIATION...DGM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
307 PM EDT SAT AUG 8 2015 .SYNOPSIS... LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL MOVE NORTHEAST AND ALLOW DRIER AND COOLER AIR TO SETTLE OVER THE AREA THROUGH EARLY NEXT WEEK. RAIN CHANCES WILL INCREASE TUESDAY INTO WEDNESDAY AS A COLD FRONT MAKES ITS WAY THROUGH THE REGION. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT LATE WEDNESDAY INTO THE EARLY PART OF NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SATURDAY...THE SURFACE LOW WAS LOCATED OFFSHORE OF CAPE HATTERAS AND LIFTING NORTHEAST. STRATOCU WILL PERSIST IN WRAPAROUND CIRCULATION THROUGH THE REMAINDER OF THE AFTERNOON. A FEW VERY SMALL AND ISOLATED SHOWERS HAVE POPPED UP ALONG THE NORTHERN TIER OF THE CWA. THE HRRR DOES DEVELOP SOME OF THIS ACTIVITY FURTHER AS IS MOVES SOUTHWARD SO AM INCLINED TO KEEP A SMALL POP FOR ISOLATED SHOWERS THROUGH SUNSET. OVERNIGHT...LOW CLOUDS SHOULD CONTINUE TO DECREASE HOWEVER MAY SEE SOME UPPER-LEVEL REMNANTS FROM THE DYING MCC IN THE PLAINS. LIGHT NNE FLOW OVERNIGHT WILL HINDER FOG DEVELOPMENT BUT WILL LET MIN TEMPS FALL JUST BELOW CLIMO MOST AREAS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...AGREEABLE AND EARLY FALL-TYPE FEEL DAYBREAK SUNDAY WITH MINIMUMS HAVING DIPPED INTO THE UPPER 60S MOST AREAS BUT WELL REMOVED FROM RECORD LOWS FOR AUGUST 9TH OF 60 AT ILM IN 1997...60 AT FLO IN 2002...AND 62 AT CRE IN 2004. SUNSHINE WILL BE MORE IN ABUNDANCE SUNDAY AND MONDAY COMPARED TO RECENT DAYS. THE RELATIVELY LOW DEWPOINT READINGS WILL RESULT IN AN AIR-MASS WHICH IS PLEASANTLY VOID OF HIGH HUMIDITY CONTENT...ALTHOUGH RETURN FLOW AND INCREASING ABSOLUTE HUMIDITY WILL LIKELY BE OBSERVED LATE MON. LATE MONDAY NIGHT INTO VERY EARLY TUESDAY AN APPROACHING SHORTWAVE AND ASSOCIATED FRONTAL SYSTEM WILL DELIVER A CHANCE OF RAINFALL. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...THE MAIN FOCUS OF THE EXTENDED WILL BE ON THE COLD FRONT MOVING ACROSS THE REGION LATE TUESDAY INTO EARLY WEDNESDAY. A POTENT MID LEVEL SHORTWAVE WILL MOVE ACROSS THE GREAT LAKES/MIDWEST ALONG WITH THIS FRONT. MEDIUM RANGE GUIDANCE SHOWS FEW CHANGES THIS AFTERNOON AND WE CONTINUE TO ADVERTISE GOOD CHANCE POPS FOR TUESDAY AND INTO PART OF WEDNESDAY. THE FRONT MAKES IT ALL THE WAY TO THE FLORIDA PANHANDLE INITIALLY THEN STALLS. SOME GUIDANCE SHOWS THE FRONT A LITTLE FURTHER TO THE NORTH BEFORE WASHING OUT. WILL KEEP SLIGHT CHANCE POPS IN FOR LATER PERIODS TO ADDRESS. TEMPERATURES THROUGHOUT THE PERIOD ARE WITHIN A COUPLE OF DEGREES OF CLIMATOLOGY. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... AS OF 18Z...STUBBORN STRATUS WILL SLOWLY RISE AND SCATTER BY MID AFTERNOON. ALMOST A DUE NORTH WIND TODAY...GUSTY NEAR THE COAST. CLEARING SKIES TONIGHT WITH SOME PATCHY FOG POSSIBLE...MAINLY INLAND. FOG SHOULD STAY IN THE MVFR RANGE. SUNDAY...A NICE AVIATION DAY WITH NEARLY CLEAR SKIES AND A LIGHT NORTHEAST WIND AND WEAK HIGH PRESSURE IN PLACE. SOME ISOLATED CONVECTION IS POSSIBLE OVER THE WESTERN PORTION OF THE REGION...LIKELY AFTER THE TAF TIME WINDOW. EXTENDED OUTLOOK...SCATTERED STORMS POSSIBLE ON MONDAY AND TUESDAY...WITH PERIODS OF MVFR POSSIBLE. OTHERWISE EXPECT VFR THROUGH THE EXTENDED PERIOD. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SATURDAY...THE SURFACE LOW WAS LOCATED OFF THE COAST OF CAPE HATTERAS AND MOVING NORTHEAST THIS AFTERNOON. A NORTHERLY WIND TRAJECTORY ON THE BACK SIDE OF THE LOW WILL CONTINUE OVERNIGHT...AND THE PRESSURE GRADIENT WILL TREND WEAKER. THERE IS AN OUTSIDE CHANCE OF A STRAY SHOWER OVERNIGHT...HOWEVER FOR THE MOST PART EXPECT NO SIGNIFICANT REDEVELOPMENT OVER THE WATERS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...N-NE WINDS WILL BE GRACING THE 0-20 NM WATERS DAYBREAK SUNDAY WITH SURFACE LOW PRESSURE ABOUT 100 NM OFFSHORE OF CAPE HATTERAS. LATE SUNDAY A TRANSITION PERIOD...AS WINDS SWING FROM THE SE 12 KT OR LESS. SE WINDS MONDAY WILL INCREASE MONDAY NIGHT TO 13-18 KT AND BECOME S-SSW AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM FROM THE WEST. NO ADVISORIES APPEAR TO BE NEEDED FOR THIS TIME PERIOD CURRENTLY. A FEW MARINE TSTMS ARE POSSIBLE VERY EARLY TUESDAY BY THE PRE-DAWN HOURS. SEAS SUNDAY MAINLY NE WAVES 3-4 FT EVERY 5-6 SECONDS. SEAS MONDAY ENE 2-3 FT EVERY 6-7 SECONDS AND ESE WAVES 1-2 FT EVERY 10 SECONDS. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...SOUTHWEST WINDS OF 15-20 KNOTS WILL PERSIST OVER THE WATERS TUESDAY INTO WEDNESDAY MORNING. A COLD FRONT WILL EASE ACROSS THE WATERS WEDNESDAY WITH WINDS TURNING TO NORTHWEST WITH A VERY LIGHT SPEED. BY THURSDAY HIGH PRESSURE BUILDS IN FURTHER ALLOWING A BETTER DEFINED NORTHEAST FLOW TO DEVELOP. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...CRM SHORT TERM...MJC LONG TERM...SHK AVIATION...DL/CRM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1240 PM CDT SAT AUG 8 2015 .UPDATE... ISSUED AT 1240 PM CDT SAT AUG 8 2015 LATEST RADAR LOOPS INDICATE ONLY SMALL SHOWERS...LIKELY FROM MIDDLE CLOUDS...ALONG THE ND/SD BORDER IN THE FAR WEST. MAY OR MAY NOT BE REACHING THE GROUND. LATEST ITERATIONS OF THE HRRR HAVE INDICATED SHOWERS ADVANCING NORTHEASTWARD A BIT SLOWER THAN EXPECTED. HAVE LOWERED CHANCES OF SHOWERS EARLY THIS AFTERNOON...THEN INCREASED TO SCATTERED/LIKELY CHANCES OF THUNDERSHOWERS IN THE SOUTHWEST BY MID-AFTERNOON. ALSO RAISED THE FORECAST MAX TEMPERATURES IN THE SOUTH CENTRAL/SOUTHEAST PART OF THE STATE WITH CLOUD COVER IN SD NOT YET REACHING NORTHWARD INTO THE STATE AND HOURLY TRENDS ON THE UPSWING A BIT HIGHER THAN IN PREVIOUS FORECAST. UPDATE ISSUED AT 934 AM CDT SAT AUG 8 2015 FOG HAS DISSIPATED ACROSS THE JAMES VALLEY AREA...WITH SOME LOW CLOUDS STILL LINGERING IN LAMOURE COUNTY. ADJUSTED HOURLY TEMPERATURE TRENDS...BUT OTHERWISE THE FORECAST REMAINS ON TRACK. UPDATE ISSUED AT 641 AM CDT SAT AUG 8 2015 PATCHY FOG HAS DISSIPATED NEAR THE JAMESTOWN ASOS...BUT THERE ARE LIKELY STILL SOME PATCHES IN VALLEYS. THUS...LEFT PATCHY FOG IN THE FORECAST FOR A COUPLE MORE HOURS. OTHERWISE...THE FORECAST LOOKS TO BE ON TRACK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 410 AM CDT SAT AUG 8 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS SOUTHWEST LATER TODAY AND INCLUDING THE SOUTH CENTRAL TONIGHT. CURRENTLY...ZONAL FLOW ALOFT REMAINS OVER THE NORTHERN PLAINS WITH STACKED LOW PRESSURE MOVING SLOWLY EAST ACROSS SOUTHERN MANITOBA AND UPPER LEVEL RIDGING OVER THE CENTRAL PLAINS. MOSTLY CLEAR SKIES OVER MUCH OF WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. T/TD SPREADS AT OR NEAR ZERO OVER MANY OBSERVING SITES OVER NORTHERN NORTH DAKOTA AND ACROSS BOTH THE WESTERN DEVILS LAKE AND JAMES RIVER BASINS. LAST FEW HRRR RUNS CONTINUE TO INDICATE AT LEAST PATCHY FOG DEVELOPMENT OVER THESE AREAS YET EARLY THIS MORNING AND WILL LEAVE IN THE FORECAST. EMBEDDED SHORT WAVE TROUGH/IMPULSE LIFTING EAST-NORTHEAST ACROSS THE INTERMOUNTAIN WEST THIS MORNING WILL TRACK EASTWARD INTO THE NORTHERN HIGH PLAINS TODAY...THEN INTO AND ACROSS THE DAKOTAS LATER TONIGHT INTO SUNDAY. ASSOCIATED SURFACE LOW WILL MOVE FROM WYOMING THIS MORNING INTO SOUTH DAKOTA LATER TODAY AND TONIGHT. PRECIPITATION WILL START TO DEVELOP INTO SOUTHWEST NORTH DAKOTA THIS AFTERNOON WITH THE APPROACH OF THE MID LEVEL WAVE AND AS THE SFC LOW MOVES INTO WESTERN SOUTH DAKOTA. PRECIPITATION THEN SPREADS SLOWLY EAST INTO MY SOUTH CENTRAL COUNTIES TONIGHT. RIDGE OF SURFACE HIGH PRESSURE BUILDING OVER FAR SOUTH CENTRAL CANADA/NORTHERN ND WILL KEEP MOST AREAS NORTH OF INTERSTATE 94 DRY. HEAVIEST RAINFALL EXPECTED TO REMAIN OVER SOUTH DAKOTA. CAPE RATHER WEAK BUT ENOUGH TO LEAVE A SLIGHT CHANCE/ISOLATED MENTION OF THUNDERSTORMS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 347 AM CDT SAT AUG 8 2015 THE FOCUS THIS MORNING IS ON SUBTROPICAL RIDGE LOCATION. THE MAIN CHANGE IN MODEL CONSENSUS OVER THE PAST 48 HOURS HAS BEEN THE WESTWARD SHIFTING OF THE SUBTROPICAL RIDGE AXIS FROM THE CENTRAL DAKOTAS INTO WESTERN MONTANA BY WEDNESDAY. THE SLOWER PROGRESSION OF CYCLONIC FLOW WILL ACT TO EXTEND THE DRY PERIOD NEXT WEEK AND INCREASE HIGH TEMPERATURES ACROSS THE DAKOTAS. GREATER UNCERTAINTY CREEPS INTO THE FORECAST ON WEDNESDAY NIGHT...AS MID LEVEL SHORTWAVES MAKE IT INTO THE DAKOTAS IN A FEW GEFS MEMBERS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1240 PM CDT SAT AUG 8 2015 LOW PRESSURE ACROSS SOUTHERN MANITOBA WILL MOVE SLOWLY EAST TODAY...REPLACED WITH A SURFACE RIDGE. SOME SCATTERED CU AT KISN/KMOT ON THE SOUTHWEST EDGE OF THE INFLUENCE OF THE MANITOBA LOW. FOR SOUTHERN ND TAFS...EXPECTING INCREASING CLOUDS DURING THE AFTERNOON/EVENING...BEGINNING WITH MID LEVEL CLOUDS AND BECOMING MVFR LATE TONIGHT. BEST CHANCE OF SHOWERS REACHING THE I94 CORRIDOR WHERE TAF SITES RESIDE IS LATE. EXPECT SHOWERS AND SCATTERED THUNDERSTORMS TO OCCUR THIS AFTERNOON/EVENING SOUTH OF THE TAF SITES...AT KHEI...LINTON FOR EXAMPLE. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...NH LONG TERM...SCHECK AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
934 AM CDT SAT AUG 8 2015 .UPDATE... ISSUED AT 934 AM CDT SAT AUG 8 2015 FOG HAS DISSIPATED ACROSS THE JAMES VALLEY AREA...WITH SOME LOW CLOUDS STILL LINGERING IN LAMOURE COUNTY. ADJUSTED HOURLY TEMPERATURE TRENDS...BUT OTHERWISE THE FORECAST REMAINS ON TRACK. UPDATE ISSUED AT 641 AM CDT SAT AUG 8 2015 PATCHY FOG HAS DISSIPATED NEAR THE JAMESTOWN ASOS...BUT THERE ARE LIKELY STILL SOME PATCHES IN VALLEYS. THUS...LEFT PATCHY FOG IN THE FORECAST FOR A COUPLE MORE HOURS. OTHERWISE...THE FORECAST LOOKS TO BE ON TRACK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 410 AM CDT SAT AUG 8 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS SOUTHWEST LATER TODAY AND INCLUDING THE SOUTH CENTRAL TONIGHT. CURRENTLY...ZONAL FLOW ALOFT REMAINS OVER THE NORTHERN PLAINS WITH STACKED LOW PRESSURE MOVING SLOWLY EAST ACROSS SOUTHERN MANITOBA AND UPPER LEVEL RIDGING OVER THE CENTRAL PLAINS. MOSTLY CLEAR SKIES OVER MUCH OF WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. T/TD SPREADS AT OR NEAR ZERO OVER MANY OBSERVING SITES OVER NORTHERN NORTH DAKOTA AND ACROSS BOTH THE WESTERN DEVILS LAKE AND JAMES RIVER BASINS. LAST FEW HRRR RUNS CONTINUE TO INDICATE AT LEAST PATCHY FOG DEVELOPMENT OVER THESE AREAS YET EARLY THIS MORNING AND WILL LEAVE IN THE FORECAST. EMBEDDED SHORT WAVE TROUGH/IMPULSE LIFTING EAST-NORTHEAST ACROSS THE INTERMOUNTAIN WEST THIS MORNING WILL TRACK EASTWARD INTO THE NORTHERN HIGH PLAINS TODAY...THEN INTO AND ACROSS THE DAKOTAS LATER TONIGHT INTO SUNDAY. ASSOCIATED SURFACE LOW WILL MOVE FROM WYOMING THIS MORNING INTO SOUTH DAKOTA LATER TODAY AND TONIGHT. PRECIPITATION WILL START TO DEVELOP INTO SOUTHWEST NORTH DAKOTA THIS AFTERNOON WITH THE APPROACH OF THE MID LEVEL WAVE AND AS THE SFC LOW MOVES INTO WESTERN SOUTH DAKOTA. PRECIPITATION THEN SPREADS SLOWLY EAST INTO MY SOUTH CENTRAL COUNTIES TONIGHT. RIDGE OF SURFACE HIGH PRESSURE BUILDING OVER FAR SOUTH CENTRAL CANADA/NORTHERN ND WILL KEEP MOST AREAS NORTH OF INTERSTATE 94 DRY. HEAVIEST RAINFALL EXPECTED TO REMAIN OVER SOUTH DAKOTA. CAPE RATHER WEAK BUT ENOUGH TO LEAVE A SLIGHT CHANCE/ISOLATED MENTION OF THUNDERSTORMS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 347 AM CDT SAT AUG 8 2015 THE FOCUS THIS MORNING IS ON SUBTROPICAL RIDGE LOCATION. THE MAIN CHANGE IN MODEL CONSENSUS OVER THE PAST 48 HOURS HAS BEEN THE WESTWARD SHIFTING OF THE SUBTROPICAL RIDGE AXIS FROM THE CENTRAL DAKOTAS INTO WESTERN MONTANA BY WEDNESDAY. THE SLOWER PROGRESSION OF CYCLONIC FLOW WILL ACT TO EXTEND THE DRY PERIOD NEXT WEEK AND INCREASE HIGH TEMPERATURES ACROSS THE DAKOTAS. GREATER UNCERTAINTY CREEPS INTO THE FORECAST ON WEDNESDAY NIGHT...AS MID LEVEL SHORTWAVES MAKE IT INTO THE DAKOTAS IN A FEW GEFS MEMBERS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 641 AM CDT SAT AUG 8 2015 PATCHY FOG NEAR KJMS WILL DISSIPATE BY 13Z. LOW PRESSURE ACROSS SOUTHERN MANITOBA WILL MOVE SLOWLY EAST TODAY...REPLACED WITH A SURFACE RIDGE. SKIES WILL BE MOSTLY CLEAR NORTH WITH INCREASING CLOUDS SOUTH DURING THE DAY. VFR CONDITIONS EXPECTED. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...NH LONG TERM...SCHECK AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
644 AM CDT SAT AUG 8 2015 .UPDATE... ISSUED AT 641 AM CDT SAT AUG 8 2015 PATCHY FOG HAS DISSIPATED NEAR THE JAMESTOWN ASOS...BUT THERE ARE LIKELY STILL SOME PATCHES IN VALLEYS. THUS...LEFT PATCHY FOG IN THE FORECAST FOR A COUPLE MORE HOURS. OTHERWISE...THE FORECAST LOOKS TO BE ON TRACK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 410 AM CDT SAT AUG 8 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS SOUTHWEST LATER TODAY AND INCLUDING THE SOUTH CENTRAL TONIGHT. CURRENTLY...ZONAL FLOW ALOFT REMAINS OVER THE NORTHERN PLAINS WITH STACKED LOW PRESSURE MOVING SLOWLY EAST ACROSS SOUTHERN MANITOBA AND UPPER LEVEL RIDGING OVER THE CENTRAL PLAINS. MOSTLY CLEAR SKIES OVER MUCH OF WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. T/TD SPREADS AT OR NEAR ZERO OVER MANY OBSERVING SITES OVER NORTHERN NORTH DAKOTA AND ACROSS BOTH THE WESTERN DEVILS LAKE AND JAMES RIVER BASINS. LAST FEW HRRR RUNS CONTINUE TO INDICATE AT LEAST PATCHY FOG DEVELOPMENT OVER THESE AREAS YET EARLY THIS MORNING AND WILL LEAVE IN THE FORECAST. EMBEDDED SHORT WAVE TROUGH/IMPULSE LIFTING EAST-NORTHEAST ACROSS THE INTERMOUNTAIN WEST THIS MORNING WILL TRACK EASTWARD INTO THE NORTHERN HIGH PLAINS TODAY...THEN INTO AND ACROSS THE DAKOTAS LATER TONIGHT INTO SUNDAY. ASSOCIATED SURFACE LOW WILL MOVE FROM WYOMING THIS MORNING INTO SOUTH DAKOTA LATER TODAY AND TONIGHT. PRECIPITATION WILL START TO DEVELOP INTO SOUTHWEST NORTH DAKOTA THIS AFTERNOON WITH THE APPROACH OF THE MID LEVEL WAVE AND AS THE SFC LOW MOVES INTO WESTERN SOUTH DAKOTA. PRECIPITATION THEN SPREADS SLOWLY EAST INTO MY SOUTH CENTRAL COUNTIES TONIGHT. RIDGE OF SURFACE HIGH PRESSURE BUILDING OVER FAR SOUTH CENTRAL CANADA/NORTHERN ND WILL KEEP MOST AREAS NORTH OF INTERSTATE 94 DRY. HEAVIEST RAINFALL EXPECTED TO REMAIN OVER SOUTH DAKOTA. CAPE RATHER WEAK BUT ENOUGH TO LEAVE A SLIGHT CHANCE/ISOLATED MENTION OF THUNDERSTORMS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 347 AM CDT SAT AUG 8 2015 THE FOCUS THIS MORNING IS ON SUBTROPICAL RIDGE LOCATION. THE MAIN CHANGE IN MODEL CONSENSUS OVER THE PAST 48 HOURS HAS BEEN THE WESTWARD SHIFTING OF THE SUBTROPICAL RIDGE AXIS FROM THE CENTRAL DAKOTAS INTO WESTERN MONTANA BY WEDNESDAY. THE SLOWER PROGRESSION OF CYCLONIC FLOW WILL ACT TO EXTEND THE DRY PERIOD NEXT WEEK AND INCREASE HIGH TEMPERATURES ACROSS THE DAKOTAS. GREATER UNCERTAINTY CREEPS INTO THE FORECAST ON WEDNESDAY NIGHT...AS MID LEVEL SHORTWAVES MAKE IT INTO THE DAKOTAS IN A FEW GEFS MEMBERS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 641 AM CDT SAT AUG 8 2015 PATCHY FOG NEAR KJMS WILL DISSIPATE BY 13Z. LOW PRESSURE ACROSS SOUTHERN MANITOBA WILL MOVE SLOWLY EAST TODAY...REPLACED WITH A SURFACE RIDGE. SKIES WILL BE MOSTLY CLEAR NORTH WITH INCREASING CLOUDS SOUTH DURING THE DAY. VFR CONDITIONS EXPECTED. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SCHECK SHORT TERM...NH LONG TERM...SCHECK AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
413 AM CDT SAT AUG 8 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 410 AM CDT SAT AUG 8 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS SOUTHWEST LATER TODAY AND INCLUDING THE SOUTH CENTRAL TONIGHT. CURRENTLY...ZONAL FLOW ALOFT REMAINS OVER THE NORTHERN PLAINS WITH STACKED LOW PRESSURE MOVING SLOWLY EAST ACROSS SOUTHERN MANITOBA AND UPPER LEVEL RIDGING OVER THE CENTRAL PLAINS. MOSTLY CLEAR SKIES OVER MUCH OF WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. T/TD SPREADS AT OR NEAR ZERO OVER MANY OBSERVING SITES OVER NORTHERN NORTH DAKOTA AND ACROSS BOTH THE WESTERN DEVILS LAKE AND JAMES RIVER BASINS. LAST FEW HRRR RUNS CONTINUE TO INDICATE AT LEAST PATCHY FOG DEVELOPMENT OVER THESE AREAS YET EARLY THIS MORNING AND WILL LEAVE IN THE FORECAST. EMBEDDED SHORT WAVE TROUGH/IMPULSE LIFTING EAST-NORTHEAST ACROSS THE INTERMOUNTAIN WEST THIS MORNING WILL TRACK EASTWARD INTO THE NORTHERN HIGH PLAINS TODAY...THEN INTO AND ACROSS THE DAKOTAS LATER TONIGHT INTO SUNDAY. ASSOCIATED SURFACE LOW WILL MOVE FROM WYOMING THIS MORNING INTO SOUTH DAKOTA LATER TODAY AND TONIGHT. PRECIPITATION WILL START TO DEVELOP INTO SOUTHWEST NORTH DAKOTA THIS AFTERNOON WITH THE APPROACH OF THE MID LEVEL WAVE AND AS THE SFC LOW MOVES INTO WESTERN SOUTH DAKOTA. PRECIPITATION THEN SPREADS SLOWLY EAST INTO MY SOUTH CENTRAL COUNTIES TONIGHT. RIDGE OF SURFACE HIGH PRESSURE BUILDING OVER FAR SOUTH CENTRAL CANADA/NORTHERN ND WILL KEEP MOST AREAS NORTH OF INTERSTATE 94 DRY. HEAVIEST RAINFALL EXPECTED TO REMAIN OVER SOUTH DAKOTA. CAPE RATHER WEAK BUT ENOUGH TO LEAVE A SLIGHT CHANCE/ISOLATED MENTION OF THUNDERSTORMS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 347 AM CDT SAT AUG 8 2015 THE FOCUS THIS MORNING IS ON SUBTROPICAL RIDGE LOCATION. THE MAIN CHANGE IN MODEL CONSENSUS OVER THE PAST 48 HOURS HAS BEEN THE WESTWARD SHIFTING OF THE SUBTROPICAL RIDGE AXIS FROM THE CENTRAL DAKOTAS INTO WESTERN MONTANA BY WEDNESDAY. THE SLOWER PROGRESSION OF CYCLONIC FLOW WILL ACT TO EXTEND THE DRY PERIOD NEXT WEEK AND INCREASE HIGH TEMPERATURES ACROSS THE DAKOTAS. GREATER UNCERTAINTY CREEPS INTO THE FORECAST ON WEDNESDAY NIGHT...AS MID LEVEL SHORTWAVES MAKE IT INTO THE DAKOTAS IN A FEW GEFS MEMBERS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 410 AM CDT SAT AUG 8 2015 LOW PRESSURE ACROSS SOUTHERN MANITOBA WILL MOVE SLOWLY EAST TODAY...REPLACED WITH A SURFACE RIDGE. SKIES WILL BE MOSTLY CLEAR NORTH WITH INCREASING CLOUDS SOUTH DURING THE DAY. VFR CONDITIONS EXPECTED. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...NH LONG TERM...SCHECK AVIATION...NH
AREA FORECAST DISCUSSION
NWS NORMAN OK
1035 PM CDT SUN AUG 9 2015 .DISCUSSION... && .AVIATION... A WEAK FRONT WILL MOVE FROM NORTHERN TO CENTRAL OKLAHOMA MONDAY MORNING. ISOLATED THUNDERSTORMS ARE POSSIBLE NEAR AND ALONG THE FRONT ON MONDAY. && .PREV DISCUSSION... /ISSUED 913 PM CDT SUN AUG 9 2015/ UPDATE... UPDATED HOURLY TEMPERATURE/DEWPOINT/WIND GRIDS. DISCUSSION... SFC OBSERVATIONS INDICATE POOLING OF MOISTURE ACROSS PORTIONS OF NORTHERN OKLAHOMA. MANY LOCATIONS ARE REPORTING DEWPOINTS IN THE LOW TO MID 70S. THIS POOLING MIGHT BE A RESULT OF A REMNANT OUTFLOW BOUNDARY. OPTED TO INCREASE DEWPOINTS TO BETTER FIT WITH CURRENT OBSERVATIONS. MINOR ADJUSTMENTS WERE ALSO MADE TO THE TEMPERATURE AND WIND GRIDS. OTHERWISE...THE FORECAST REMAINS ON TRACK. THE LAST FEW HRRR RUNS AND THE LATEST NAM INDICATE A CONTINUED CHANCE OF SHOWERS AND STORMS NEAR THE KANSAS/OKLAHOMA BORDER OVERNIGHT. MAHALE PREV DISCUSSION... /ISSUED 706 PM CDT SUN AUG 9 2015/ DISCUSSION... AVIATION... THUNDERSTORMS WILL OCCASIONALLY AFFECT NORTHWEST OKLAHOMA INTO TONIGHT. A WEAK FRONT WILL MOVE FROM NORTHERN TO CENTRAL OKLAHOMA MONDAY MORNING. ISOLATED THUNDERSTORMS ARE POSSIBLE NEAR AND ALONG THE FRONT ON MONDAY. PREV DISCUSSION... /ISSUED 254 PM CDT SUN AUG 9 2015/ DISCUSSION... A FEW SHOWERS CONTINUE TO LINGER ALONG THE STATIONARY FRONT THIS AFTERNOON ACROSS EXTREME NORTHERN OK. SOUTH OF HERE...AN OUTFLOW BOUNDARY CAN BE SEEN SLOWLY MOVING TO THE SOUTH FROM NEAR HENNESSEY TO PERRY. ISOLATED STORMS MAY MANAGE TO DEVELOP ALONG THIS BOUNDARY THROUGH THE AFTERNOON/EARLY EVENING...PERHAPS AS FAR WEST AS CLINTON. IF THEY DO...THEY WILL HAVE THE POTENTIAL TO PRODUCE SEVERE WIND GUSTS. OTHERWISE...STILL EXPECT HIGHEST POPS LATER TONIGHT ALONG THE BOUNDARY ACROSS NW AND NORTHERN OK AS A SHORTWAVE TROUGH ROUNDS THE RIDGE. SOME HEAVY RAINFALL AND WIND GUSTS NEAR 40 TO 50 MPH WILL BE THE MAIN THREATS WITH THESE STORMS. AS THE FRONT SLOWLY PROGRESSES SOUTHWARD TOMORROW MORNING THROUGH TOMORROW AFTERNOON...LOW POPS WILL ACCOMPANY IT OVER CENTRAL OK. STILL EXPECT HEAT INDICES AHEAD OF THE FRONT TO EXCEED 105 DEGREES SO ANOTHER HEAT ADVISORY HAS BEEN ISSUED FOR SOUTHERN OK. DEPENDING ON CLOUD COVER/LINGERING PRECIP TOMORROW HIGH TEMPS MAY NEED TO BE INCREASED FURTHER NORTH...WHICH COULD RESULT IN AN EXPANSION OF THE HEAT ADVISORY INTO CENTRAL OK. BELOW AVG TEMPS ARE STILL EXPECTED BEHIND THE FRONT TUE-FRI. BY TUESDAY...MOST OF THE RAIN CHCS WILL SHIFT TO THE NW/W WITHIN A MID LEVEL MOIST AXIS AS SEVERAL MID LEVEL SHORTWAVE TROUGHS CONTINUE TO ROUND THE EASTERN FRINGE OF THE RIDGE. IT APPEARS RAIN CHANCES WILL SLOWLY SHIFT EAST INTO CENTRAL OK THROUGH THROUGH MID WEEK BEFORE DRIER AIR IMPACTS THE REGION FRI. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 75 96 73 90 / 20 30 20 10 HOBART OK 75 99 74 93 / 20 30 20 30 WICHITA FALLS TX 77 103 77 97 / 0 10 20 20 GAGE OK 71 94 70 87 / 50 30 30 30 PONCA CITY OK 76 95 72 88 / 40 20 10 10 DURANT OK 76 104 77 96 / 0 0 10 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...HEAT ADVISORY FROM 1 PM TO 8 PM CDT MONDAY FOR OKZ032-039>043- 045>048-050>052. TX...NONE. && $$ 10/09/09
AREA FORECAST DISCUSSION
NWS NORMAN OK
913 PM CDT SUN AUG 9 2015 .UPDATE... UPDATED HOURLY TEMPERATURE/DEWPOINT/WIND GRIDS. && .DISCUSSION... SFC OBSERVATIONS INDICATE POOLING OF MOISTURE ACROSS PORTIONS OF NORTHERN OKLAHOMA. MANY LOCATIONS ARE REPORTING DEWPOINTS IN THE LOW TO MID 70S. THIS POOLING MIGHT BE A RESULT OF A REMNANT OUTFLOW BOUNDARY. OPTED TO INCREASE DEWPOINTS TO BETTER FIT WITH CURRENT OBSERVATIONS. MINOR ADJUSTMENTS WERE ALSO MADE TO THE TEMPERATURE AND WIND GRIDS. OTHERWISE...THE FORECAST REMAINS ON TRACK. THE LAST FEW HRRR RUNS AND THE LATEST NAM INDICATE A CONTINUED CHANCE OF SHOWERS AND STORMS NEAR THE KANSAS/OKLAHOMA BORDER OVERNIGHT. MAHALE && .PREV DISCUSSION... /ISSUED 706 PM CDT SUN AUG 9 2015/ DISCUSSION... AVIATION... THUNDERSTORMS WILL OCCASIONALLY AFFECT NORTHWEST OKLAHOMA INTO TONIGHT. A WEAK FRONT WILL MOVE FROM NORTHERN TO CENTRAL OKLAHOMA MONDAY MORNING. ISOLATED THUNDERSTORMS ARE POSSIBLE NEAR AND ALONG THE FRONT ON MONDAY. PREV DISCUSSION... /ISSUED 254 PM CDT SUN AUG 9 2015/ DISCUSSION... A FEW SHOWERS CONTINUE TO LINGER ALONG THE STATIONARY FRONT THIS AFTERNOON ACROSS EXTREME NORTHERN OK. SOUTH OF HERE...AN OUTFLOW BOUNDARY CAN BE SEEN SLOWLY MOVING TO THE SOUTH FROM NEAR HENNESSEY TO PERRY. ISOLATED STORMS MAY MANAGE TO DEVELOP ALONG THIS BOUNDARY THROUGH THE AFTERNOON/EARLY EVENING...PERHAPS AS FAR WEST AS CLINTON. IF THEY DO...THEY WILL HAVE THE POTENTIAL TO PRODUCE SEVERE WIND GUSTS. OTHERWISE...STILL EXPECT HIGHEST POPS LATER TONIGHT ALONG THE BOUNDARY ACROSS NW AND NORTHERN OK AS A SHORTWAVE TROUGH ROUNDS THE RIDGE. SOME HEAVY RAINFALL AND WIND GUSTS NEAR 40 TO 50 MPH WILL BE THE MAIN THREATS WITH THESE STORMS. AS THE FRONT SLOWLY PROGRESSES SOUTHWARD TOMORROW MORNING THROUGH TOMORROW AFTERNOON...LOW POPS WILL ACCOMPANY IT OVER CENTRAL OK. STILL EXPECT HEAT INDICES AHEAD OF THE FRONT TO EXCEED 105 DEGREES SO ANOTHER HEAT ADVISORY HAS BEEN ISSUED FOR SOUTHERN OK. DEPENDING ON CLOUD COVER/LINGERING PRECIP TOMORROW HIGH TEMPS MAY NEED TO BE INCREASED FURTHER NORTH...WHICH COULD RESULT IN AN EXPANSION OF THE HEAT ADVISORY INTO CENTRAL OK. BELOW AVG TEMPS ARE STILL EXPECTED BEHIND THE FRONT TUE-FRI. BY TUESDAY...MOST OF THE RAIN CHCS WILL SHIFT TO THE NW/W WITHIN A MID LEVEL MOIST AXIS AS SEVERAL MID LEVEL SHORTWAVE TROUGHS CONTINUE TO ROUND THE EASTERN FRINGE OF THE RIDGE. IT APPEARS RAIN CHANCES WILL SLOWLY SHIFT EAST INTO CENTRAL OK THROUGH THROUGH MID WEEK BEFORE DRIER AIR IMPACTS THE REGION FRI. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 75 96 73 90 / 20 30 20 10 HOBART OK 75 99 74 93 / 30 30 20 30 WICHITA FALLS TX 77 103 77 97 / 0 10 20 20 GAGE OK 71 94 70 87 / 50 30 30 30 PONCA CITY OK 76 95 72 88 / 40 20 10 10 DURANT OK 76 104 77 96 / 0 0 10 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...HEAT ADVISORY FROM 1 PM TO 8 PM CDT MONDAY FOR OKZ032-039>043- 045>048-050>052. TX...NONE. && $$ 10/11
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
518 PM EDT SAT AUG 8 2015 .SYNOPSIS... HIGH PRESSURE OVER CENTRAL QUEBEC CANADA WILL RIDGE SOUTH INTO THE AREA TODAY. WEAK LOW PRESSURE WILL MOVE OUT OF THE OHIO VALLEY LATER SUNDAY AND SUNDAY NIGHT...BRINGING MORE HUMID AND UNSETTLED CONDITIONS THAT WILL BRING RAIN THE TO THE REGION MONDAY AND TUESDAY. HIGH PRESSURE SHOULD DOMINATE THE REST OF THE COMING WORK WEEK FROM WEDNESDAY TO FRIDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... WEAK UPPER TROFFING AND SOME UPWARD VERTICAL MOTION BEING FORCED BY THE APPROACHING LEFT EXIT OF AN UPPER JET STREAK HAVE ALLOWED THE SKY TO FILL WITH PUFFY CU. SO FAR JUST LIGHT RETURNS ON RADAR...SOME OVER SOMERSET COUNTY AND A FEW OTHERS NORTH OF THE NY BORDER. RAP MESO ANAL SHOWS A FINGER CAPE EXCEEDING 1000J POKING UP INTO WESTERN PA...WITH INSTABILITY OVER CENTRAL AREAS MUCH MORE SUPPRESSED. ENSEMBLES SHOW SMALL CHANCE POPS...FOR THE NEXT 6-8 HOURS...OVER THE LAURELS WITH THE SREF WETTER THAN THE SEEMINGLY MORE REASONABLE GEFS. HRRR SUPPORTS THE IDEA OF JUST SOME SMALL CELLULAR CONVECTION DEVELOPING OVER THE NEXT FEW HOURS...THEN DYING AFTER SUNDOWN...LEAVING THE BULK OF THE OVERNIGHT PRECIP- FREE. OVERNIGHT LOWS IN THE MID 50S TO MID 60S WILL BE VERY NEAR NORMAL FOR EARLY AUGUST. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... CONDITIONS SHOULD WARM AND PARTIALLY CLEAR SUNDAY AS THE UPPER HEIGHTS CONTINUE TO SLOWLY BUILD AND THE MEAN BLYR FLOW WEAKENS AND BECOMES WEST OR NW. WEAK SHORTWAVE ENERGY RIDING THE BUILDING RIDGE IS TIMED INTO THE REGION DURING MAX HEATING...LEADING TO THE DEVELOPMENT OF A BIT MORE IN THE WAY OF INSTABILITY THAN TODAY. I STILL KEPT POPS ON THE LOW SIDE...BUT THE AREA COVERAGE FOR THE CHANCE OF A POP-UP SHOWER OR THUNDERSTORMS WILL BE A BIT LARGER...MAINLY SUNDAY AFTERNOON. HIGH TEMPS WILL RANGE FROM NEAR 80 OVER THE FAR NORTH TO MID 80S OVER THE FAR SOUTH. VERY NEAR OR MAYBE A TAD BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... AN APPROACHING COLD FRONT AND DEEPENING TROUGH OVER EASTERN NORTH AMERICA WILL BE THE KEY PLAYER IN THE WEATHER DURING THIS PERIOD. THE FRONT COULD PROVIDE US RAIN MON-TUE AND THE DEEPENING TROUGH COOL DRY WEATHER WED-FRI. WARM MOIST AIR WILL MOVE IN AHEAD OF THE APPROACHING COLD FRONT. THIS WILL INCREASE THE CHANCE OF RAIN OVERNIGHT MONDAY INTO TUESDAY. BASED ON THE NCEP GEFS AND SREF-PARA THE CHANCE OF RAIN GOES UP SLOWLY SUNDAY NIGHT INTO MONDAY EVENING. THEN IT COMES UP FAST MONDAY AFTERNOON AND OVERNIGHT INTO TUESDAY. AT THIS TIME BEST CHANCE OF RAIN SHOULD BE AROUND 2 PM MONDAY UNTIL ABOUT 8 AM TUESDAY. THE RAIN PROBABILITIES IN THE GEFS BEGIN TO DROP OFF FAST AFTER 8 AM TUESDAY. POPS GET LOW AFTER 8 PM TUESDAY AND THE REST OF THE PERIOD WED-FRIDAY LOOKS TO BE DRY AT THIS TIME. THE POTENTIAL FOR A WIDESPREAD 0.5 TO 0.8 INCH RAINFALL EVENT IS CURRENTLY FORECAST AS THE FRONTAL SYSTEM MOVES ACROSS THE STATE. BIAS CORRECTING THESE DATA WOULD IMPLY PERHAPS 0.25 TO 0.50 INCHES OF RAIN IS MORE LIKELY. THE SURGE OF HIGH PW AIR MONDAY-TUESDAY IS REPLACED BY BELOW NORMALLY LOW PW AIR WEDNESDAY INTO FRIDAY. IT WILL BE VERY DRY AFTER THE RAIN. IN ADDITION TO THE DRY AIR...THE GEFS AND NAEFS FORECAST BELOW NORMAL 850 HPA TEMPERATURES IMPLYING WEDNESDAY-FRIDAY WILL BE SLIGHTLY COOLER THAN NORMAL. THE TEMPERATURES SHOULD BEGIN TO REBOUND ON FRIDAY AND INTO NEXT WEEKEND. SHOULD BE A COOL DRY PERIOD. THE FLY IN THE OINTMENT IS ALWAYS THE COLD AIR ALOFT WHICH COULD TRIGGER ISOLATED SHOWERS OUR COARSER LONGER RANGE MODELS WILL NOT PICK UP ON. WE CANNOT RULE OUT ISOLATED INSTABILITY SHOWERS WEDNESDAY AFTERNOON AND WE HAVE NO SKILL FORECASTING THESE AT 4 DAYS OUT. BUT THE DEEP TROUGH AND MID-LEVEL COOL AIR IS A PATTERN WHICH MIGHT FAVOR SUCH A SCENARIO WEDNESDAY AND POSSIBLY THURSDAY BUT WOULD NOT PUT THAT IN FORECAST AT THIS TIME RANGE. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... A FEW SHOWERS ACROSS THE SW. ADDED VCSH TO JST. OTHERWISE MINOR ADJUSTMENTS TO 21Z TAF PACKAGE. EARLIER DISCUSSION BELOW. MAINLY VFR CONDITIONS EXPECTED THROUGH SUNDAY. SCT-BKN CUMULUS CLOUDS HAVE DEVELOPED AND WILL COVER MUCH OF THE AIRSPACE THROUGH LATE DAY WITH A SMALL CHANCE OF A STRAY SHOWER...MAINLY OVER THE LAUREL HIGHLANDS INTO THE NORTHERN MOUNTAINS THROUGH EVENING. SLOWLY INCREASING LOW LEVEL MOISTURE OVERNIGHT WILL LEAD TO THE POSSIBILITY OF A FEW HOURS OF MVFR/IFR AROUND SUNRISE. CONDITIONS WILL IMPROVE RAPIDLY AFTER SUNRISE SUNDAY WITH ANOTHER DAY VERY MUCH LIKE TODAY...WITH HIGH BASED CLOUDS AND LIGHT WINDS. THERE COULD BE A STRAY AFTERNOON OR EVENING SHOWER/THUNDERSTORMS IN SPOTS. OUTLOOK... MON-TUE...VFR-MVFR. SHOWERS LKLY/ISOLD TSTMS. WED...MVFR-VFR CIGS/SCT SHOWERS WEST. MAINLY VFR CENTRAL/EAST. THU...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...GRUMM AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
254 PM EDT SAT AUG 8 2015 .SYNOPSIS... HIGH PRESSURE OVER CENTRAL QUEBEC CANADA WILL RIDGE SOUTH INTO THE AREA TODAY. WEAK LOW PRESSURE WILL MOVE OUT OF THE OHIO VALLEY LATER SUNDAY AND SUNDAY NIGHT...BRINGING MORE HUMID AND UNSETTLED CONDITIONS THAT WILL BRING RAIN THE TO THE REGION MONDAY AND TUESDAY. HIGH PRESSURE SHOULD DOMINATE THE REST OF THE COMING WORK WEEK FROM WEDNESDAY TO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... WEAK UPPER TROFFING AND SOME UPWARD VERTICAL MOTION BEING FORCED BY THE APPROACHING LEFT EXIT OF AN UPPER JET STREAK HAVE ALLOWED THE SKY TO FILL WITH PUFFY CU. SO FAR JUST LIGHT RETURNS ON RADAR...SOME OVER SOMERSET COUNTY AND A FEW OTHERS NORTH OF THE NY BORDER. RAP MESO ANAL SHOWS A FINGER CAPE EXCEEDING 1000J POKING UP INTO WESTERN PA...WITH INSTABILITY OVER CENTRAL AREAS MUCH MORE SUPPRESSED. ENSEMBLES SHOW SMALL CHANCE POPS...FOR THE NEXT 6-8 HOURS...OVER THE LAURELS WITH THE SREF WETTER THAN THE SEEMINGLY MORE REASONABLE GEFS. HRRR SUPPORTS THE IDEA OF JUST SOME SMALL CELLULAR CONVECTION DEVELOPING OVER THE NEXT FEW HOURS...THEN DYING AFTER SUNDOWN...LEAVING THE BULK OF THE OVERNIGHT PRECIP- FREE. OVERNIGHT LOWS IN THE MID 50S TO MID 60S WILL BE VERY NEAR NORMAL FOR EARLY AUGUST. && .SHORT TERM /SUNDAY/... CONDITIONS SHOULD WARM AND PARTIALLY CLEAR SUNDAY AS THE UPPER HEIGHTS CONTINUE TO SLOWLY BUILD AND THE MEAN BLYR FLOW WEAKENS AND BECOMES WEST OR NW. WEAK SHORTWAVE ENERGY RIDING THE BUILDING RIDGE IS TIMED INTO THE REGION DURING MAX HEATING...LEADING TO THE DEVELOPMENT OF A BIT MORE IN THE WAY OF INSTABILITY THAN TODAY. I STILL KEPT POPS ON THE LOW SIDE...BUT THE AREA COVERAGE FOR THE CHANCE OF A POP-UP SHOWER OR THUNDERSTORMS WILL BE A BIT LARGER...MAINLY SUNDAY AFTERNOON. HIGH TEMPS WILL RANGE FROM NEAR 80 OVER THE FAR NORTH TO MID 80S OVER THE FAR SOUTH. VERY NEAR OR MAYBE A TAD BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... AN APPROACHING COLD FRONT AND DEEPENING TROUGH OVER EASTERN NORTH AMERICA WILL BE THE KEY PLAYER IN THE WEATHER DURING THIS PERIOD. THE FRONT COULD PROVIDE US RAIN MON-TUE AND THE DEEPENING TROUGH COOL DRY WEATHER WED-FRI. WARM MOIST AIR WILL MOVE IN AHEAD OF THE APPROACHING COLD FRONT. THIS WILL INCREASE THE CHANCE OF RAIN OVERNIGHT MONDAY INTO TUESDAY. BASED ON THE NCEP GEFS AND SREF-PARA THE CHANCE OF RAIN GOES UP SLOWLY SUNDAY NIGHT INTO MONDAY EVENING. THEN IT COMES UP FAST MONDAY AFTERNOON AND OVERNIGHT INTO TUESDAY. AT THIS TIME BEST CHANCE OF RAIN SHOULD BE AROUND 2 PM MONDAY UNTIL ABOUT 8 AM TUESDAY. THE RAIN PROBABILITIES IN THE GEFS BEGIN TO DROP OFF FAST AFTER 8 AM TUESDAY. POPS GET LOW AFTER 8 PM TUESDAY AND THE REST OF THE PERIOD WED-FRIDAY LOOKS TO BE DRY AT THIS TIME. THE POTENTIAL FOR A WIDESPREAD 0.5 TO 0.8 INCH RAINFALL EVENT IS CURRENTLY FORECAST AS THE FRONTAL SYSTEM MOVES ACROSS THE STATE. BIAS CORRECTING THESE DATA WOULD IMPLY PERHAPS 0.25 TO 0.50 INCHES OF RAIN IS MORE LIKELY. THE SURGE OF HIGH PW AIR MONDAY-TUESDAY IS REPLACED BY BELOW NORMALLY LOW PW AIR WEDNESDAY INTO FRIDAY. IT WILL BE VERY DRY AFTER THE RAIN. IN ADDITION TO THE DRY AIR...THE GEFS AND NAEFS FORECAST BELOW NORMAL 850 HPA TEMPERATURES IMPLYING WEDNESDAY-FRIDAY WILL BE SLIGHTLY COOLER THAN NORMAL. THE TEMPERATURES SHOULD BEGIN TO REBOUND ON FRIDAY AND INTO NEXT WEEKEND. SHOULD BE A COOL DRY PERIOD. THE FLY IN THE OINTMENT IS ALWAYS THE COLD AIR ALOFT WHICH COULD TRIGGER ISOLATED SHOWERS OUR COARSER LONGER RANGE MODELS WILL NOT PICK UP ON. WE CANNOT RULE OUT ISOLATED INSTABILITY SHOWERS WEDNESDAY AFTERNOON AND WE HAVE NO SKILL FORECASTING THESE AT 4 DAYS OUT. BUT THE DEEP TROUGH AND MID-LEVEL COOL AIR IS A PATTERN WHICH MIGHT FAVOR SUCH A SCENARIO WEDNESDAY AND POSSIBLY THURSDAY BUT WOULD NOT PUT THAT IN FORECAST AT THIS TIME RANGE. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... MAINLY VFR CONDITIONS EXPECTED THROUGH SUNDAY. SCT-BKN CUMULUS CLOUDS HAVE DEVELOPED AND WILL COVER MUCH OF THE AIRSPACE THROUGH LATE DAY WITH A SMALL CHANCE OF A STRAY SHOWER...MAINLY OVER THE LAUREL HIGHLANDS INTO THE NORTHERN MOUNTAINS THROUGH EVENING. SLOWLY INCREASING LOW LEVEL MOISTURE OVERNIGHT WILL LEAD TO THE POSSIBILITY OF A FEW HOURS OF MVFR/IFR AROUND SUNRISE. CONDITIONS WILL IMPROVE RAPIDLY AFTER SUNRISE SUNDAY WITH ANOTHER DAY VERY MUCH LIKE TODAY...WITH HIGH BASED CLOUDS AND LIGHT WINDS. THERE COULD BE A STRAY AFTERNOON OR EVENING SHOWER/THUNDERSTORMS IN SPOTS. OUTLOOK... MON-TUE...VFR-MVFR. SHOWERS LKLY/ISOLD TSTMS. WED...MVFR-VFR CIGS/SCT SHOWERS WEST. MAINLY VFR CENTRAL/EAST. THU...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...GRUMM AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
218 PM EDT SAT AUG 8 2015 .SYNOPSIS... HIGH PRESSURE OVER CENTRAL QUEBEC CANADA WILL RIDGE SOUTH INTO THE AREA TODAY. WEAK LOW PRESSURE WILL MOVE OUT OF THE OHIO VALLEY LATER SUNDAY AND SUNDAY NIGHT...BRINGING MORE HUMID AND UNSETTLED CONDITIONS THAT WILL LAST INTO THE START OF THE NEW WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... WEAK UPPER TROFFING AND SOME UPWARD VERTICAL MOTION BEING FORCED BY THE APPROACHING LEFT EXIT OF AN UPPER JET STREAK HAVE ALLOWED THE SKY TO FILL WITH PUFFY CU. SO FAR JUST LIGHT RETURNS ON RADAR...SOME OVER SOMERSET COUNTY AND A FEW OTHERS NORTH OF THE NY BORDER. RAP MESO ANAL SHOWS A FINGER CAPE EXCEEDING 1000J POKING UP INTO WESTERN PA...WITH INSTABILITY OVER CENTRAL AREAS MUCH MORE SUPPRESSED. ENSEMBLES SHOW SMALL CHANCE POPS...FOR THE NEXT 6-8 HOURS...OVER THE LAURELS WITH THE SREF WETTER THAN THE SEEMINGLY MORE REASONABLE GEFS. HRRR SUPPORTS THE IDEA OF JUST SOME SMALL CELLULAR CONVECTION DEVELOPING OVER THE NEXT FEW HOURS...THEN DYING AFTER SUNDOWN...LEAVING THE BULK OF THE OVERNIGHT PRECIP- FREE. OVERNIGHT LOWS IN THE MID 50S TO MID 60S WILL BE VERY NEAR NORMAL FOR EARLY AUGUST. && .SHORT TERM /SUNDAY/... CONDITIONS SHOULD WARM AND PARTIALLY CLEAR SUNDAY AS THE UPPER HEIGHTS CONTINUE TO SLOWLY BUILD AND THE MEAN BLYR FLOW WEAKENS AND BECOMES WEST OR NW. WEAK SHORTWAVE ENERGY RIDING THE BUILDING RIDGE IS TIMED INTO THE REGION DURING MAX HEATING...LEADING TO THE DEVELOPMENT OF A BIT MORE IN THE WAY OF INSTABILITY THAN TODAY. I STILL KEPT POPS ON THE LOW SIDE...BUT THE AREA COVERAGE FOR THE CHANCE OF A POP-UP SHOWER OR THUNDERSTORMS WILL BE A BIT LARGER...MAINLY SUNDAY AFTERNOON. HIGH TEMPS WILL RANGE FROM NEAR 80 OVER THE FAR NORTH TO MID 80S OVER THE FAR SOUTH. VERY NEAR OR MAYBE A TAD BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... A WEAK TROUGH OF LOW PRESSURE AT THE SURFACE AND ALOFT SLIDE SLOWLY SE ACROSS THE STATE EARLY NEXT WEEK. USING THE GEFS ENSEMBLES THE STRONGEST FLOW AND MOISTURE REMAINS TO THE NORTH AND EAST OF CENTRAL PA. THERE/S ONLY A SLIGHT CHANCE OF SHOWERS SUNDAY AFTERNOON. THIS IS SPECIFICALLY THE RESULT OF A WEAK SHORTWAVE RIDING N PERIPHERY OF MISS VALLEY UPPER RIDGE. GEFS PLUMES INDICATE A GRADUAL WARMING TREND INTO THE WEEKEND...WITH READINGS CLOSE TO AVERAGE FOR EARLY AUGUST. THE MODELS FOR THE LONG RANGE PATTERN COME TO A FAIR AGREEMENT THOUGH SLIGHT TIMING DIFFERENCES ARE PRESENT. THE NEXT WEATHER SYSTEM...AND THE BEST CHANCE FOR PRECIPITATION WILL BE A COLD FRONT THAT PASSES THROUGH TUESDAY. WITH SLOW MOVEMENT OF FRONT... HAVE GIVEN A BROAD BRUSH OF POPS MONDAY NIGHT THROUGH TUESDAY NIGHT. HAVE KEPT MAIN FRONTAL PASSAGE LATE TUESDAY INTO TUE NIGHT...THOUGH CAN/T RULE OUT THE FRONT STALLING AND PASSING WEDNESDAY. HIGHER PWATS WORK INTO THE REGION ON SW FLOW AS HGTS FALL AHEAD OF APPROACHING TROF MONDAY...SO CHC OF SHRA/TSRA CONTINUES. DEEPENING TROUGH POSSIBLY STALLED COLD FRONT WILL LKLY RESULT IN SCATTERED SHRA/TSRA TUESDAY NIGHT INTO WEDNESDAY. THE GEFS AND EC BOTH CURRENTLY INDICATE THE POSSIBILITY OF HVY RAINFALL ACROSS EASTERN PA ASSOC WITH THIS SLOWING FRONT. COOLER/DRIER WX IS LIKELY BY MIDWEEK AS THE LONG TERM PATTERN WILL BE DOMINATED BY A ROTATING QUASI-STATIONARY UPPER LEVEL LOW CENTERED OVER EASTERN CANADA. EXPECT THIS SYSTEM TO BRING COOL MID LVL TEMPS OVR THE REGION AND COULD PROMOTE PM SHOWERS...ESP OVR THE MTNS THROUGH THE LATTER HALF OF NEXT WEEK. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... MAINLY VFR CONDITIONS EXPECTED THROUGH SUNDAY. SCT-BKN CUMULUS CLOUDS HAVE DEVELOPED AND WILL COVER MUCH OF THE AIRSPACE THROUGH LATE DAY WITH A SMALL CHANCE OF A STRAY SHOWER...MAINLY OVER THE LAUREL HIGHLANDS INTO THE NORTHERN MOUNTAINS THROUGH EVENING. SLOWLY INCREASING LOW LEVEL MOISTURE OVERNIGHT WILL LEAD TO THE POSSIBILITY OF A FEW HOURS OF MVFR/IFR AROUND SUNRISE. CONDITIONS WILL IMPROVE RAPIDLY AFTER SUNRISE SUNDAY WITH ANOTHER DAY VERY MUCH LIKE TODAY...WITH HIGH BASED CLOUDS AND LIGHT WINDS. THERE COULD BE A STRAY AFTERNOON OR EVENING SHOWER/THUNDERSTORMS IN SPOTS. OUTLOOK... MON-TUE...VFR-MVFR. SHOWERS LKLY/ISOLD TSTMS. WED...MVFR-VFR CIGS/SCT SHOWERS WEST. MAINLY VFR CENTRAL/EAST. THU...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LAMBERT/RXR AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1029 AM EDT SAT AUG 8 2015 .SYNOPSIS... HIGH PRESSURE OVER CENTRAL QUEBEC CANADA WILL RIDGE SOUTH INTO THE AREA TODAY. WEAK LOW PRESSURE WILL MOVE OUT OF THE CENTRAL UNITED STATES LATER SUNDAY AND SUNDAY NIGHT...BRINGING MORE HUMID AND UNSETTLED CONDITIONS THAT WILL LAST INTO THE START OF THE NEW WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH PRESSURE TO THE NORTH WILL KEEP MOST AREAS DRY AND PARTLY TO MOSTLY SUNNY TODAY. THE REGION IS UNDER A GENERAL WEAKNESS IN THE UPPER AIR PATTERN. THE APPROACH OF A JET STREAK OUT OF THE LOWER GR LAKES LATER TODAY COULD PROVIDE JUST ENOUGH LIFT TO TRIGGER AN ISOLATED SHOWER OR TWO. MID LEVEL LAPSE RATES ARE EXPECTED TO BE WEAK AND WHILE THE MODELS DEVELOP SOME CAPE...IT WILL BE VERY MEAGER. HRRR SHOWS SOME WIDELY SCATTERED SMALL CELLULAR CONVECTION WHICH GENERALLY EQUATES TO NOT MUCH OF ANYTHING HAPPENING...SO I BACKED OFF THE POPS PRETTY HARD...CONFINING THE VERY LOW CHANCES FOR A POP UP SHOWER MAINLY TO OUR WESTERN HIGHER TERRAIN. HIGH TEMPS TODAY WILL RANGE FROM THE MID 70S ACROSS THE LAUREL HIGHLANDS AND PORTIONS OF THE NRN MTNS...TO THE U70S TO L80S ACROSS THE SUSQ VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... PERSISTENT...JET EXIT REGION AND ASSOCIATED WEAK-MDT LIFT WILL BE OVR THE REGION TONIGHT AND SUNDAY. THIS HIGHER LEVEL UVVEL AND CONTINUED LIGHT EASTERLY FLOW IN THE UPPER BLYR WILL HELP TO MAINTAIN PLENTY OF CLOUDS AND SOME SPOTTY SHOWERS. LOWS EARLY SUNDAY WILL BE IN THE MID TO UPPER 50S OVER THE NORTHERN MOUNTAINS...AND LOWER TO MID 60S IN THE SOUTHERN VALLEYS. CONDITIONS SHOULD WARM AND PARTIALLY CLEAR SUNDAY AS THE MEAN BLYR FLOW WEAKENS AND BECOMES WEST OR NW. A LIGHT SHOWER CAN`T BE RULED OUT SUNDAY...BUT MOST OF THEM SHOULD OCCUR FROM THE CENTRAL MTS TO THE LAUREL HIGHLANDS. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A WEAK TROUGH OF LOW PRESSURE AT THE SURFACE AND ALOFT SLIDE SLOWLY SE ACROSS THE STATE EARLY NEXT WEEK. USING THE GEFS ENSEMBLES THE STRONGEST FLOW AND MOISTURE REMAINS TO THE NORTH AND EAST OF CENTRAL PA. THERE/S ONLY A SLIGHT CHANCE OF SHOWERS SUNDAY AFTERNOON. THIS IS SPECIFICALLY THE RESULT OF A WEAK SHORTWAVE RIDING N PERIPHERY OF MISS VALLEY UPPER RIDGE. GEFS PLUMES INDICATE A GRADUAL WARMING TREND INTO THE WEEKEND...WITH READINGS CLOSE TO AVERAGE FOR EARLY AUGUST. THE MODELS FOR THE LONG RANGE PATTERN COME TO A FAIR AGREEMENT THOUGH SLIGHT TIMING DIFFERENCES ARE PRESENT. THE NEXT WEATHER SYSTEM...AND THE BEST CHANCE FOR PRECIPITATION WILL BE A COLD FRONT THAT PASSES THROUGH TUESDAY. WITH SLOW MOVEMENT OF FRONT... HAVE GIVEN A BROAD BRUSH OF POPS MONDAY NIGHT THROUGH TUESDAY NIGHT. HAVE KEPT MAIN FRONTAL PASSAGE LATE TUESDAY INTO TUE NIGHT...THOUGH CAN/T RULE OUT THE FRONT STALLING AND PASSING WEDNESDAY. HIGHER PWATS WORK INTO THE REGION ON SW FLOW AS HGTS FALL AHEAD OF APPROACHING TROF MONDAY...SO CHC OF SHRA/TSRA CONTINUES. DEEPENING TROUGH POSSIBLY STALLED COLD FRONT WILL LKLY RESULT IN SCATTERED SHRA/TSRA TUESDAY NIGHT INTO WEDNESDAY. THE GEFS AND EC BOTH CURRENTLY INDICATE THE POSSIBILITY OF HVY RAINFALL ACROSS EASTERN PA ASSOC WITH THIS SLOWING FRONT. COOLER/DRIER WX IS LIKELY BY MIDWEEK AS THE LONG TERM PATTERN WILL BE DOMINATED BY A ROTATING QUASI-STATIONARY UPPER LEVEL LOW CENTERED OVER EASTERN CANADA. EXPECT THIS SYSTEM TO BRING COOL MID LVL TEMPS OVR THE REGION AND COULD PROMOTE PM SHOWERS...ESP OVR THE MTNS THROUGH THE LATTER HALF OF NEXT WEEK. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS EXPECTED THROUGH MOST OF THE WEEKEND. SCT-BKN MID CLOUDS SHOULD COVER MUCH OF THE AIRSPACE TODAY WITH LOW CONFIDENCE IN A STRAY SHOWER...MAINLY OVER THE LAUREL HIGHLANDS INTO THE NORTHERN MOUNTAINS THIS AFTERNOON AND EVENING. SHORT DURATION SUB-VFR RESTRICTIONS ARE POSSIBLE DURING THE PREDAWN AND EARLY MORNING HOURS SUNDAY DUE TO PATCHY FOG/LOW CLOUDS. MORE ACTIVE WX FCST INTO EARLY NEXT WEEK WITH SHOWERS/TSTMS LKLY MON INTO TUE. OUTLOOK... MON-TUE...VFR-MVFR. SHOWERS LKLY/ISOLD TSTMS. WED...MVFR-VFR CIGS/SCT SHOWERS WEST. MAINLY VFR CENTRAL/EAST. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...FITZGERALD/LAMBERT LONG TERM...LAMBERT/RXR AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1057 PM CDT SUN AUG 9 2015 .AVIATION... 06Z TAFS...STILL SOME QUESTION ON TIMING OF CONVECTION THROUGH THE OVERNIGHT HOURS. SCATTERED THUNDERSTORMS HAVE AND WILL CONTINUE TO DEVELOP ACROSS THE NORTHERN AND CENTRAL TEXAS PANHANDLE...AND SLOWLY SUBSIDE BY MORNING. COVERAGE IS EXPECTED TO INCREASE AGAIN TOMORROW AFTERNOON AND EVENING ACROSS THE PANHANDLES...STARTING WITH PROB30 IN THE AFTERNOON AND PREVAILING ACROSS NORTHERN SITES LATE MONDAY NIGHT. CONFIDENCE IS LOW IN WIND DIRECTION AT KAMA AS A WEAK BOUNDARY REMAINS NEAR THE AREA AND IS UNCLEAR HOW QUICKLY WINDS WILL SHIFT NORTHEASTERLY BEHIND IT. ELSENHEIMER && .PREV DISCUSSION... /ISSUED 431 PM CDT SUN AUG 9 2015/ DISCUSSION... A WEAK BOUNDARY SLOWLY SAGGING SOUTH SHOULD BE THE FOCUS FOR STORM DEVELOPMENT THIS AFTERNOON AND INTO THE OVERNIGHT HOURS. STORMS COULD ALSO DEVELOP ALONG AN AREA OF CONVERGENCE FROM CANADIAN TO BUSHLAND. THIS DEVELOPMENT IS SHOWN IN THE HRRR OUTPUT, BUT MORNING CLOUD COVER HAS SLOWED THE WARMING IN THESE AREAS WHICH MAY DELAY THE INITIATION TO LATER IN THIS EVENING. ANY STORMS THAT DO DEVELOP ALONG THIS CONVERGENCE AREA SHOULD MOVE OFF INTO WESTERN OKLAHOMA LATER THIS EVENING AS A WEAK SHORTWAVE SEEN IN WATER VAPOR IMAGERY OVER SOUTHERN NEW MEXICO ROUND THE RIDGE. THIS SHORTWAVE SHOULD ALSO HELP CONVECTION TO DEVELOP ALONG THE SOUTHWARD MOVING BOUNDARY. BOTH ROUNDS OF STORMS SHOULD HAVE THE POTENTIAL TO BECOME STRONG TO MARGINALLY SEVERE WITH AROUND 2000 J/KG AND DEEP LAYER SHEAR AROUND 20-25KT. HEAVY RAIN WILL ALSO BE OF CONCERN WITH ANY STORM THAT DEVELOPS. PWAT VALUES OVERNIGHT CONTINUE TO HOVER RIGHT AROUND THE +2SD FOR THIS TIME OF YEAR. WHILE AVERAGE FORECAST AMOUNTS RANGE FROM A QUARTER OF AN INCH UP TO THREE QUARTERS OF AN INCH, THERE REMAINS AS RISK FOR LOCALIZED AMOUNTS UP TO 1.5 INCHES WITH THE STORMS THROUGH MONDAY MORNING. A FEW LINGERING SHOWERS AND THUNDERSTORMS ARE POSSIBLE FOR THE MONDAY MORNING COMMUTE BUT RAINFALL AMOUNTS FROM THESE STORMS SHOULD BE LESS THAN THE OVERNIGHT STORMS. AFTER A BRIEF LULL AROUND MIDDAY THE NEXT ROUND OF STORMS IS EXPECTED TO DEVELOP AS THE UPPER LEVEL FLOW BECOMES MORE NORTHWESTERLY. THE WIND SHIFT, WHILE MOSTLY SOUTH OF THE PANHANDLES, SHOULD STILL BE POSITIONED TO ALLOW SIZABLE ISENTROPIC UPGLIDE MONDAY AFTERNOON INTO TUESDAY. THE THOUGHT OF A FLASH FLOOD WATCH FOR MONDAY AFTERNOON INTO TUESDAY MORNING CONTINUES TO COME UP BUT THERE HAS BEEN SIGNIFICANT DISCREPANCIES BETWEEN MODEL RUNS. YESTERDAY THE GFS SHOWED UP TO 3 INCHES FOR THE NORTHWEST AND SHOWS AROUND AN INCH STORM TOTAL (JUST LIKE THE ECMWF SHOWED YESTERDAY). TODAY IT`S THE MORNING NAM WHICH SHOWS 2-4 INCHES ACROSS THE WESTERN OKLAHOMA PANHANDLE WITH EVEN HIGHER AMOUNTS IN SOUTHEASTERN COLORADO (ALTHOUGH THE 18Z RUN HAS ALREADY BEGUN TO BACK OFF ON THESE AMOUNTS). AS A RESULT OF THESE DISCREPANCIES WILL HOLD OFF ON ISSUING A WATCH UNTIL THE IMPACTED AREA CAN BE NARROWED DOWN. RAINFALL AMOUNTS WITH THIS ROUND ARE EXPECTED TO BE HIGHEST ACROSS THE NORTHERN TEXAS AND OKLAHOMA PANHANDLES AND RANGE BETWEEN THREE QUARTERS OF AN INCH UP TO 1.5 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. AMOUNTS ACROSS THE SOUTHERN TEXAS PANHANDLE LOOK TO RANGE BETWEEN A QUARTER OF AN INCH UP TO THREE QUARTERS OF AN INCH WITH LOCALLY HIGHER AMOUNTS POSSIBLE. WEDNESDAY THROUGH THE REST OF THE WEEK...THE RIDGE CONTINUES TO MOVE INTO THE CONTINENTAL DIVIDE TO KEEP THE PANHANDLES WITH A NORTH- NORTHWEST FLOW REGIME ALOFT. THIS WILL KEEP OFF AN ON RAIN CHANCES IN THE FORECAST AND SLIGHTLY COOLER TEMPERATURES THROUGH THE END OF THE WEEK. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 18/6
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
852 PM CDT SUN AUG 9 2015 .UPDATE... /NPW CANCELED/ ALL HEAT INDEX REPORTS IN THE AREA FELL BELOW 105 AND WELL BELOW THE ADVISORY CRITERIA OF 108/110 DEGREES FOR EAST/WEST COUNTIES. A SPECIAL WEATHER STATEMENT FOR THE NEXT COUPLE DAYS REPLACES THE CANCELED HEAT ADVISORY. && .PREV DISCUSSION... /ISSUED 637 PM CDT SUN AUG 9 2015/ AVIATION.../00Z TAF CYCLE/ VFR SKC ACROSS MUCH OF THE REGION WITH ONLY A FEW/SCT250 CIRRUS CLOUDS AS OF 09/2330Z. VFR WILL CONTINUE UNTIL 09Z OR SO WITH DEVELOPMENT OF MVFR STRATUS CLOUDS INVOF KSAT/KSSF AND KAUS THROUGH 14-15Z. HIGHEST CONFIDENCE EXISTS FOR SAT/SSF PER SOUNDING ANALYSIS AND HRRR OUTPUT. KAUS COULD ALSO BE IMPACTED WITH BKN015 CIGS BUT MAY BE MORE SPORADIC. KDRT SHOULD STAY VFR THROUGH THE NIGHT BUT STRATUS WAS CLOSE BY THIS MORNING AND THIS TREND WILL NEED TO MONITORED IN THE 06Z TAF ISSUANCE. CURRENT SURFACE WINDS OF 10-15 KT OUT OF THE SE WILL CALM TO 5-10KT OVERNIGHT. VFR CONDITIONS WILL PREVAIL MONDAY AFTER 15Z WITH A REPEAT OF TODAY. PREV DISCUSSION... /ISSUED 240 PM CDT SUN AUG 9 2015/ SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)... HIGH PRESSURE RIDGE CONTINUES TO DOMINATE THIS AFTERNOON. CURRENT HEAT ADVISORY WILL EXPIRE THIS EVENING. PEAK HEATING HAS YET TO OCCUR BUT LOOKS LIKE A FEW SPOTS WILL HIT ADVISORY CRITERIA MAINLY OVER THE FAR EAST...DECENT MIXING ACROSS THE REST OF THE AREA WILL DROP DEW POINTS THROUGH THE DAY. MILD NIGHT TONIGHT WITH A REPEAT OF STRATUS FORMATION ACROSS CENTRAL SECTIONS WITH STRONGER LOW LEVEL SOUTHERLY FLOW. ANOTHER HOT DAY ON MONDAY BUT THE UPPER RIDGE WILL START A WESTWARD MOVEMENT THAT WILL BRING SLIGHT ADJUSTMENTS TO POP AND TEMPS LATER IN THE WEEK. FAIRLY LOW DEWPOINTS WILL GENERALLY KEEP AREA HEAT INDEX VALUES JUST BELOW HEAT ADVISORY CRITERIA LEVELS. A WEAK FRONT WILL PUSH SOUTH INTO THE RED RIVER AREA...HELPING TO DECREASE THE GRADIENT MONDAY NIGHT AND LIMIT THE EARLY MORNING CLOUD COVER BY TUESDAY. LONG TERM (TUESDAY THROUGH SUNDAY)... AS THE UPPER RIDGE SHIFTS WEST BY MID WEEK...A SIMILAR PATTERN WILL DEVELOP LIKE THE END OF JULY. A WEAK BACKDOOR COOL FRONT WILL PUSH INTO EAST AND NE TEXAS AS MID AND UPPER FLOW BECOMES INCREASINGLY EASTERLY/NORTHEASTERLY. RH TIME SECTIONS SHOWS AN INCREASE IN MID LEVEL MOISTURE STARTING LATE TUE INTO WED. THIS MOISTURE INCREASE...ALONG WITH THE EXPECTED HOT TEMPS...SHOULD BE ENOUGH TO FIRE UP ISOLATED/SCT CONVECTION DURING THE AFTERNOON/EVENING HOURS ON WED AND AGAIN ON THU. LIKE THE PREVIOUS SYSTEM ABOUT 10 DAYS AGO...STORMS COULD PRODUCE SOME STRONG DOWNDRAFTS...WITH SEVERAL OUTFLOW BOUNDARIES LIKELY HELPING TO INITIATE ADDITIONAL STORMS. THIS MID LEVEL MOISTURE WILL PUSH WEST THROUGH THE WEEK...AND BY WEEKS END...POP WILL BE CONFINED TO THE FAR WEST AND NORTHWEST. BY THE WEEKEND AND EARLY NEXT WEEK...LONG RANGE MODELS ARE SHOWING AN UPPER LOW OVER THE SE U.S. MOVING WEST ALONG THE NORTHERN GULF COAST...MOVING TOWARD THE TEXAS COAST. LOWERING 500MB HEIGHTS AND BETTER MOISTURE LEVELS WILL KEEP THE INTENSE HEAT AWAY...BUT THE HIGHER DEWPOINTS MIGHT ACTUALLY KEEP HEAT INDEX VALUES PLENTY WARM. CANT RULE OUT SOME CHANCES OF RAIN ESPECIALLY IN THE COASTAL PLAINS DUE TO THE PROXIMITY OF THE UPPER LOW. THE HOPE WILL BE FOR THIS SYSTEM AND MOISTURE TO PUSH FARTHER INLAND AND GIVE SOME RAIN CHANCES BEYOND THE 7 DAY PERIOD. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 76 102 78 101 77 / 0 0 0 - 10 AUSTIN BERGSTROM INTL AIRPORT 74 101 74 101 76 / 0 0 0 - 10 NEW BRAUNFELS MUNI AIRPORT 77 102 76 101 76 / 0 0 0 0 - BURNET MUNI AIRPORT 73 101 76 101 78 / 0 0 0 - 10 DEL RIO INTL AIRPORT 77 102 77 103 78 / 0 0 0 0 0 GEORGETOWN MUNI AIRPORT 75 102 77 102 79 / 0 0 0 - 10 HONDO MUNI AIRPORT 74 101 74 102 75 / 0 0 0 0 0 SAN MARCOS MUNI AIRPORT 76 100 75 101 77 / 0 0 0 - - LA GRANGE - FAYETTE REGIONAL 75 101 77 103 77 / 0 0 0 10 10 SAN ANTONIO INTL AIRPORT 78 101 77 101 78 / 0 0 0 0 - STINSON MUNI AIRPORT 77 102 76 101 77 / 0 0 0 0 - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...ALLEN SYNOPTIC/GRIDS...OAKS
AREA FORECAST DISCUSSION
NWS AMARILLO TX
645 PM CDT SUN AUG 9 2015 .AVIATION... CONVECTION AND A WIND SHIFT WILL BE THE MAIN FOCUS OF THE 00Z TAF ISSUANCE. ISOLATED CONVECTION HAS DEVELOPED ACROSS THE PANHANDLES THIS AFTERNOON. KAMA ALREADY HAD A STORM DEVELOP JUST OUTSIDE OF THE 10 MILE RADIUS AND HAS SINCE BEGUN TO DISSIPATE. BOTH KDHT AND KGUY WILL HAVE A CHANCE FOR CONVECTION AS THE EVENING HOURS PROGRESS. ANY STORM WHICH AFFECTS A TERMINAL COULD BE CAPABLE OF PRODUCING GUSTY WINDS UP TO 40KTS AND HEAVY RAIN WHICH COULD REDUCE FLIGHT CATEGORIES. TAF AMENDMENTS WILL BE LIKELY. EXPECT ISOLATED CONVECTIVE COVERAGE TO INCREASE ALONG A SURFACE TROUGH DROPPING SOUTHWARD OUT OF THE OKLAHOMA PANHANDLE OVERNIGHT. THERE WILL LIKELY BE A LULL IN CONVECTIVE ACTIVITY TOMORROW MORNING BEFORE THE NEXT ROUND OF STORMS DEVELOP DURING THE EARLY AFTERNOON. HAVE CARRIED PROB30 GROUPS FOR THIS NEXT ROUND OF CONVECTION. && .PREV DISCUSSION... /ISSUED 431 PM CDT SUN AUG 9 2015/ DISCUSSION... A WEAK BOUNDARY SLOWLY SAGGING SOUTH SHOULD BE THE FOCUS FOR STORM DEVELOPMENT THIS AFTERNOON AND INTO THE OVERNIGHT HOURS. STORMS COULD ALSO DEVELOP ALONG AN AREA OF CONVERGENCE FROM CANADIAN TO BUSHLAND. THIS DEVELOPMENT IS SHOWN IN THE HRRR OUTPUT, BUT MORNING CLOUD COVER HAS SLOWED THE WARMING IN THESE AREAS WHICH MAY DELAY THE INITIATION TO LATER IN THIS EVENING. ANY STORMS THAT DO DEVELOP ALONG THIS CONVERGENCE AREA SHOULD MOVE OFF INTO WESTERN OKLAHOMA LATER THIS EVENING AS A WEAK SHORTWAVE SEEN IN WATER VAPOR IMAGERY OVER SOUTHERN NEW MEXICO ROUND THE RIDGE. THIS SHORTWAVE SHOULD ALSO HELP CONVECTION TO DEVELOP ALONG THE SOUTHWARD MOVING BOUNDARY. BOTH ROUNDS OF STORMS SHOULD HAVE THE POTENTIAL TO BECOME STRONG TO MARGINALLY SEVERE WITH AROUND 2000 J/KG AND DEEP LAYER SHEAR AROUND 20-25KT. HEAVY RAIN WILL ALSO BE OF CONCERN WITH ANY STORM THAT DEVELOPS. PWAT VALUES OVERNIGHT CONTINUE TO HOVER RIGHT AROUND THE +2SD FOR THIS TIME OF YEAR. WHILE AVERAGE FORECAST AMOUNTS RANGE FROM A QUARTER OF AN INCH UP TO THREE QUARTERS OF AN INCH, THERE REMAINS AS RISK FOR LOCALIZED AMOUNTS UP TO 1.5 INCHES WITH THE STORMS THROUGH MONDAY MORNING. A FEW LINGERING SHOWERS AND THUNDERSTORMS ARE POSSIBLE FOR THE MONDAY MORNING COMMUTE BUT RAINFALL AMOUNTS FROM THESE STORMS SHOULD BE LESS THAN THE OVERNIGHT STORMS. AFTER A BRIEF LULL AROUND MIDDAY THE NEXT ROUND OF STORMS IS EXPECTED TO DEVELOP AS THE UPPER LEVEL FLOW BECOMES MORE NORTHWESTERLY. THE WIND SHIFT, WHILE MOSTLY SOUTH OF THE PANHANDLES, SHOULD STILL BE POSITIONED TO ALLOW SIZABLE ISENTROPIC UPGLIDE MONDAY AFTERNOON INTO TUESDAY. THE THOUGHT OF A FLASH FLOOD WATCH FOR MONDAY AFTERNOON INTO TUESDAY MORNING CONTINUES TO COME UP BUT THERE HAS BEEN SIGNIFICANT DISCREPANCIES BETWEEN MODEL RUNS. YESTERDAY THE GFS SHOWED UP TO 3 INCHES FOR THE NORTHWEST AND SHOWS AROUND AN INCH STORM TOTAL (JUST LIKE THE ECMWF SHOWED YESTERDAY). TODAY IT`S THE MORNING NAM WHICH SHOWS 2-4 INCHES ACROSS THE WESTERN OKLAHOMA PANHANDLE WITH EVEN HIGHER AMOUNTS IN SOUTHEASTERN COLORADO (ALTHOUGH THE 18Z RUN HAS ALREADY BEGUN TO BACK OFF ON THESE AMOUNTS). AS A RESULT OF THESE DISCREPANCIES WILL HOLD OFF ON ISSUING A WATCH UNTIL THE IMPACTED AREA CAN BE NARROWED DOWN. RAINFALL AMOUNTS WITH THIS ROUND ARE EXPECTED TO BE HIGHEST ACROSS THE NORTHERN TEXAS AND OKLAHOMA PANHANDLES AND RANGE BETWEEN THREE QUARTERS OF AN INCH UP TO 1.5 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. AMOUNTS ACROSS THE SOUTHERN TEXAS PANHANDLE LOOK TO RANGE BETWEEN A QUARTER OF AN INCH UP TO THREE QUARTERS OF AN INCH WITH LOCALLY HIGHER AMOUNTS POSSIBLE. WEDNESDAY THROUGH THE REST OF THE WEEK...THE RIDGE CONTINUES TO MOVE INTO THE CONTINENTAL DIVIDE TO KEEP THE PANHANDLES WITH A NORTH- NORTHWEST FLOW REGIME ALOFT. THIS WILL KEEP OFF AN ON RAIN CHANCES IN THE FORECAST AND SLIGHTLY COOLER TEMPERATURES THROUGH THE END OF THE WEEK. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 14
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
637 PM CDT SUN AUG 9 2015 .AVIATION.../00Z TAF CYCLE/ VFR SKC ACROSS MUCH OF THE REGION WITH ONLY A FEW/SCT250 CIRRUS CLOUDS AS OF 09/2330Z. VFR WILL CONTINUE UNTIL 09Z OR SO WITH DEVELOPMENT OF MVFR STRATUS CLOUDS INVOF KSAT/KSSF AND KAUS THROUGH 14-15Z. HIGHEST CONFIDENCE EXISTS FOR SAT/SSF PER SOUNDING ANALYSIS AND HRRR OUTPUT. KAUS COULD ALSO BE IMPACTED WITH BKN015 CIGS BUT MAY BE MORE SPORADIC. KDRT SHOULD STAY VFR THROUGH THE NIGHT BUT STRATUS WAS CLOSE BY THIS MORNING AND THIS TREND WILL NEED TO MONITORED IN THE 06Z TAF ISSUANCE. CURRENT SURFACE WINDS OF 10-15 KT OUT OF THE SE WILL CALM TO 5-10KT OVERNIGHT. VFR CONDITIONS WILL PREVAIL MONDAY AFTER 15Z WITH A REPEAT OF TODAY. && .PREV DISCUSSION... /ISSUED 240 PM CDT SUN AUG 9 2015/ SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)... HIGH PRESSURE RIDGE CONTINUES TO DOMINATE THIS AFTERNOON. CURRENT HEAT ADVISORY WILL EXPIRE THIS EVENING. PEAK HEATING HAS YET TO OCCUR BUT LOOKS LIKE A FEW SPOTS WILL HIT ADVISORY CRITERIA MAINLY OVER THE FAR EAST...DECENT MIXING ACROSS THE REST OF THE AREA WILL DROP DEW POINTS THROUGH THE DAY. MILD NIGHT TONIGHT WITH A REPEAT OF STRATUS FORMATION ACROSS CENTRAL SECTIONS WITH STRONGER LOW LEVEL SOUTHERLY FLOW. ANOTHER HOT DAY ON MONDAY BUT THE UPPER RIDGE WILL START A WESTWARD MOVEMENT THAT WILL BRING SLIGHT ADJUSTMENTS TO POP AND TEMPS LATER IN THE WEEK. FAIRLY LOW DEWPOINTS WILL GENERALLY KEEP AREA HEAT INDEX VALUES JUST BELOW HEAT ADVISORY CRITERIA LEVELS. A WEAK FRONT WILL PUSH SOUTH INTO THE RED RIVER AREA...HELPING TO DECREASE THE GRADIENT MONDAY NIGHT AND LIMIT THE EARLY MORNING CLOUD COVER BY TUESDAY. LONG TERM (TUESDAY THROUGH SUNDAY)... AS THE UPPER RIDGE SHIFTS WEST BY MID WEEK...A SIMILAR PATTERN WILL DEVELOP LIKE THE END OF JULY. A WEAK BACKDOOR COOL FRONT WILL PUSH INTO EAST AND NE TEXAS AS MID AND UPPER FLOW BECOMES INCREASINGLY EASTERLY/NORTHEASTERLY. RH TIME SECTIONS SHOWS AN INCREASE IN MID LEVEL MOISTURE STARTING LATE TUE INTO WED. THIS MOISTURE INCREASE...ALONG WITH THE EXPECTED HOT TEMPS...SHOULD BE ENOUGH TO FIRE UP ISOLATED/SCT CONVECTION DURING THE AFTERNOON/EVENING HOURS ON WED AND AGAIN ON THU. LIKE THE PREVIOUS SYSTEM ABOUT 10 DAYS AGO...STORMS COULD PRODUCE SOME STRONG DOWNDRAFTS...WITH SEVERAL OUTFLOW BOUNDARIES LIKELY HELPING TO INITIATE ADDITIONAL STORMS. THIS MID LEVEL MOISTURE WILL PUSH WEST THROUGH THE WEEK...AND BY WEEKS END...POP WILL BE CONFINED TO THE FAR WEST AND NORTHWEST. BY THE WEEKEND AND EARLY NEXT WEEK...LONG RANGE MODELS ARE SHOWING AN UPPER LOW OVER THE SE U.S. MOVING WEST ALONG THE NORTHERN GULF COAST...MOVING TOWARD THE TEXAS COAST. LOWERING 500MB HEIGHTS AND BETTER MOISTURE LEVELS WILL KEEP THE INTENSE HEAT AWAY...BUT THE HIGHER DEWPOINTS MIGHT ACTUALLY KEEP HEAT INDEX VALUES PLENTY WARM. CANT RULE OUT SOME CHANCES OF RAIN ESPECIALLY IN THE COASTAL PLAINS DUE TO THE PROXIMITY OF THE UPPER LOW. THE HOPE WILL BE FOR THIS SYSTEM AND MOISTURE TO PUSH FARTHER INLAND AND GIVE SOME RAIN CHANCES BEYOND THE 7 DAY PERIOD. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 103 76 102 78 101 / 0 0 0 0 - AUSTIN BERGSTROM INTL AIRPORT 102 74 101 74 101 / 0 0 0 0 - NEW BRAUNFELS MUNI AIRPORT 101 77 102 76 101 / 0 0 0 0 0 BURNET MUNI AIRPORT 101 73 101 76 101 / 0 0 0 0 - DEL RIO INTL AIRPORT 103 77 102 77 103 / 0 0 0 0 0 GEORGETOWN MUNI AIRPORT 102 75 102 77 102 / 0 0 0 0 - HONDO MUNI AIRPORT 101 74 101 74 102 / 0 0 0 0 0 SAN MARCOS MUNI AIRPORT 101 76 100 75 101 / 0 0 0 0 - LA GRANGE - FAYETTE REGIONAL 101 75 101 77 103 / 0 0 0 0 10 SAN ANTONIO INTL AIRPORT 101 78 101 77 101 / 0 0 0 0 0 STINSON MUNI AIRPORT 101 77 102 76 101 / 0 0 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING COUNTIES: ATASCOSA...BASTROP...BEXAR...CALDWELL...COMAL...DE WITT... DIMMIT...FAYETTE...FRIO...GONZALES...GUADALUPE...HAYS...KARNES... LAVACA...LEE...MEDINA...TRAVIS...WILLIAMSON...WILSON...ZAVALA. && $$ MESOSCALE/AVIATION...ALLEN SYNOPTIC/GRIDS...OAKS PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
234 PM CDT SAT AUG 8 2015 .SHORT TERM... BIGGEST CHANGE FROM EARLIER FORECASTS WAS TO EXPAND ISOLATED STORM MENTION EASTWARD ACROSS MUCH OF THE CAPROCK THIS EVENING. EARLY AFTERNOON ANALYSIS INDICATES A FAVORABLE COLLOCATION OF SURFACE TROUGHING AND STEEP MID-LEVEL LAPSE RATES JUST WEST OF THE TX-NM BORDER. SURFACE DEWPOINTS AREA WIDE ARE RUNNING 5-15 DEGS HIGHER THAN THIS TIME YESTERDAY AND ARE YIELDING 1000-2000 J/KG OF MLCAPE ACROSS THE SOUTH PLAINS. ALREADY NOTICING SOME CU BUILDING SOUTH OF CVS AT 19Z AS DEEP MIXING THERE CATAPULTS PARCELS TO THEIR CCL LEVELS. THIS THEME SHOULD EXPAND SOUTHWARD ALONG THE SURFACE TROUGH WITH A FEW STORMS LIKELY TO BE DOTTING OUR WESTERN ZONES BY LATE AFTERNOON. AS THESE PULSE-TYPE CELLS MOVE SLOWLY NORTHEAST...OUTFLOW REGENERATION OF NEW STORMS SEEMS PLAUSIBLE THROUGH EARLY EVENING IN LIGHT OF MEAGER CIN. HRRR HAS BEEN QUITE ADAMANT IN BLOSSOMING A LARGER COVERAGE OF STORMS BEFORE SUNSET...BUT WITH NO DISCERNIBLE BACKGROUND SUPPORT AVAILABLE IT SEEMS A SAFER BET TO KEEP PRECIP MENTION ON THE ISOLATED SIDE. A DECENT NOCTURNAL LLJ MAY KEEP SOME SEMBLANCE OF THESE EARLIER STORMS INTACT AFTER MIDNIGHT. SUNDAY WILL SEE A TALL AND CLOSED ANTICYCLONE RETROGRADE TO CENTRAL TEXAS COMPLETE WITH RISING HEIGHTS AND THICKNESSES LOCALLY. THIS PROCESS WILL HELP REORIENT THE SURFACE TROUGH FROM N-S TO NE-SW ACROSS THE WRN TX PANHANDLE INTO ERN NM. BEST STORM CHANCES SHOULD PLAY OUT IN THE NRN PANHANDLE NEAR THE INTERSECTION OF THE TROUGH AND A STALLING FRONT...BUT DEEP MIXING AND WEAK CAPE IN OUR NW COUNTIES COULD SPUR A FEW LATE AFTERNOON STORMS. OTHERWISE...MAX TEMPS LOOK TO SHAKE OUT A DEGREE OR TWO WARMER THAN TODAY. .LONG TERM... UPPER LEVEL RIDGE IS EXPECTED TO BE CENTERED OVER EAST TEXAS SUNDAY EVENING WHILST VIGOROUS UPPER LEVEL LOW SLIDES DOWN THE COAST OF BRITISH COLUMBIA. THE STRENGTH OF THE RIDGE IS EXPECTED TO BE SUFFICIENTLY STRONG TO HOLD THE LOW OFF THE PACIFIC NORTHWEST COAST AT LEAST THROUGH 120 HOURS BEFORE IT EJECTS NEWRD INTO SRN CANADA. TO OUR NORTH A SHORTWAVE PASSES EARLY MONDAY ACROSS THE CENTRAL PLAINS FOLLOWED BY ANOTHER SURGE OF ENERGY ROTATING ABOUT HUDSON BAY LOW EARLY TUESDAY BEFORE RIDGE BUILDS STRONGLY ALL THE WAY UP TO NUNAVUT. AS THE HIGH SLOWLY RETROGRADES...FLOW WILL BECOME MORE NORTHERLY TO NORTHEASTERLY WITH TIME AND THIS SHOULD HELP COOL TEMPS A BIT IN THE LATTER EXTENDED. BEST RAIN CHANCES DURING THE EXTENDED WILL EXIST FROM SUNDAY EVENING INTO TUESDAY AS FRONTAL BOUNDARY SAGS INTO THE REGION. HIGHEST POTENTIAL WILL EXIST NORTH AND WEST. TRENDS HAVE BEEN EDGING THE BOUNDARY FURTHER SOUTH WITH EACH RUN AND THIS CERTAINLY FITS THE PATTERN THIS SUMMER. THINGS LOOK TO DRY OUT ON WEDNESDAY WITH PERHAPS A FEW SCT SHOWERS NEAR THE ESCARPMENT BUT OVERALL TRENDING DRIER FOR THE REMAINDER OF THE EXTENDED. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 64 94 67 90 / 20 20 20 30 TULIA 66 95 68 92 / 20 0 20 30 PLAINVIEW 65 95 70 93 / 20 0 10 20 LEVELLAND 68 96 70 95 / 20 0 10 20 LUBBOCK 71 98 72 96 / 20 0 10 10 DENVER CITY 68 98 69 96 / 20 0 10 10 BROWNFIELD 68 98 70 96 / 20 0 10 10 CHILDRESS 73 102 75 99 / 0 0 10 20 SPUR 70 101 72 99 / 0 0 10 0 ASPERMONT 75 104 75 103 / 0 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 93/26
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY ISSUED AT 241 PM CDT SAT AUG 8 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH PRESSURE CENTERED OVER NORTHERN LAKE MICHIGAN...AND NOSING INTO THE SOUTHERN PART OF THE STATE. MEANWHILE...A COLD FRONT IS SLOWLY MOVING INTO NE MINNESOTA WHERE SMALL CLUSTERS OF THUNDERSTORMS OCCASIONALLY DEVELOP. A FEW OTHER STORMS HAVE FIRED OVER SOUTHERN MINNESOTA IN A WARM ADVECTION ZONE. OTHERWISE...LOW LEVEL COOL AIR HAS DELAYED CLEARING ACROSS MUCH OF THE REGION EXCEPT FOR FAR N-C WISCONSIN WHERE SKIES ARE STARTING TO CLEAR. AREAS OF SPRINKLES OR LIGHT RAIN ARE FALLING OUT OF A MID-DECK OVER WESTERN AND SOUTHERN WISCONSIN...BUT HAVE BEEN DISSIPATING AS THEY APPROACH CENTRAL WISCONSIN. FORECAST CONCERNS INCLUDE CLOUD TRENDS AND THUNDERSTORM POTENTIAL OVER THE NEXT 24 HOURS. TONIGHT...MID-LEVEL WARM ADVECTION WILL RAMP UP OVER SOUTHWEST WISCONSIN...WHILE A COLD FRONT SAGS INTO NORTHWEST WISCONSIN LATE. THE MAJORITY OF SHORT-TERM GUIDANCE SUGGESTS ANY CONVECTION THAT DEVELOPS OVER SOUTHERN MINNESOTA AND NORTHERN IOWA WILL DROP TO THE SOUTHEAST OF THE AREA TONIGHT. A BETTER CHANCE OF SHOWERS AND STORMS LOOK TO OCCUR OVER N-C WISCONSIN ALONG THE FRONT WHERE ELEVATED INSTABILITY WILL SHIFT INTO LATE IN THE NIGHT. THIS SEEMS REASONABLE SINCE ISOLATED CONVECTION HAS BEEN OCCURRING ALL DAY OVER NE MINNESOTA. SO LEFT A SLIGHT CHANCE TO ACCOUNT FOR THAT. OTHERWISE...CLOUD TRENDS CONTINUE TO POSE A HEADACHE. EAST TO SOUTHEAST LOW LEVEL FLOW WILL CONTINUE TO COLD ADVECT THROUGH THE EVENING OVER EASTERN WISCONSIN...BELOW A WARM LAYER CENTERED AROUND 850MB. THIS WOULD ARGUE TO SLOW DOWN THE CLEARING TREND LATER THIS AFTERNOON AND EVENING. IF CLEARING DOES OCCUR...PATCHY FOG COULD BECOME AN ISSUE...BUT THATS MAINLY OVER CENTRAL AND N-C WI. LOWS IN THE UPPER 50S TO LOW 60S. SUNDAY...WEAK MID-LEVEL WARM ADVECTION WILL SPREAD OVER NORTHEAST WISCONSIN AS THE COLD FRONT STALLS ACROSS NW WISCONSIN. COULD HAVE A FEW LIGHT SHOWERS/SPRINKLES GRAZE THE SOUTHERN FORECAST AREA IN THE WARM ADVECTION ZONE...MAINLY IN THE MORNING. MOST OF THE ATTENTION WILL BE PLACED ON THE COLD FRONT THOUGH. ISOLATED CONVECTION WILL OCCUR ACROSS N-C WISCONSIN DURING THE MORNING...BEFORE INSTABILITY BUILDS THROUGH THE AFTERNOON. PROGGED SOUNDINGS INDICATE AMPLE INSTABILITY (ML CAPE UP TO 2000 J/KG)...BUT 0-6KM BULK SHEARS ARE ONLY AROUND 20 KTS. THESE PROGGED CONDITIONS WOULD ARGUE FOR PULSE TYPE STORMS...WITH A FEW STRONG OR ISOLATED SEVERE STORMS POSSIBLE. THE BEST COVERAGE OF STORMS APPEARS TO BE AFTER 3 PM IN THE AFTERNOON. HIGHS RANGING FROM THE UPPER 70S NORTH TO MID 80S SOUTH. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY ISSUED AT 241 PM CDT SAT AUG 8 2015 A WEAK LOW PRESSURE SYSTEM OVER MANITOBA WILL MOVE EAST TO SOUTHERN HUDSON BAY DURING THE NEXT COUPLE OF DAYS. THE LOW WILL DRAG A COLD FRONT ACROSS WISCONSIN. THERE WILL BE A CHANCE FOR SHOWERS AND THUNDERSTORMS AHEAD OF AND ALONG THE FRONT...ENDING MONDAY AFTERNOON AS NORTHWEST WINDS FOLLOW IN AND MOISTURE GETS SCOURED OUT OF THE AREA. ONLY AN ISOLATED SHOWER OR TWO IS EXPECTED MONDAY NIGHT. AFTER THE FRONT MOVES ON BY...A HIGH PRESSURE RIDGE WILL STRENGTHEN OVER THE U.S. PLAINS STATES/MIDWEST. THE LONGWAVE PATTERN OVER NORTH AMERICA WILL BECOME INCREASINGLY AMPLIFIED AND A LOW PRESSURE TROUGH WILL EXPAND SOUTH OVER THE EASTERN UNITED STATES. THIS PATTERN WILL PRODUCE A NORTHWEST FLOW OVER WISCONSIN AND CREATE CONSIDERABLE UNCERTAINTY IN PRECIPITATION PREDICTION FOR THE WORK WEEK. HOWEVER...THE PREDICTION OF TEMPERATURES SHOULD BE RELIABLY WITHIN THE NORMAL TO SLIGHTLY BELOW NORMAL RANGE FOR THIS TIME OF THE YEAR THROUGH NEXT WEEKEND. THE BLEND OF MODELS SUGGESTS THAT...AFTER MONDAY...THE NEXT SIGNIFICANT CHANCE FOR PRECIPITATION COMES ON FRIDAY AS A SHORTWAVE RIDES DOWN ON THE NORTHWEST FLOW OUT OF CANADA. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1206 PM CDT SAT AUG 8 2015 CIGS WILL GRADUALLY RISE THIS AFTERNOON WITH FURTHER DAYTIME HEATING. CENTRAL AND N-C WI WILL SEE SLOWER IMPROVEMENT THAN TAF SITES OVER EASTERN WI. MOSTLY VFR TONIGHT...THOUGH VSBYS WILL LIKELY DROP LATE TONIGHT DUE TO A COMBO OF LIGHT WINDS AND HIGH HUMIDITY. A COLD FRONT WILL MOVE INTO NORTH-CENTRAL WISCONSIN ON SUNDAY BRINGING A THREAT OF SHOWERS AND STORMS. IMPACTS COULD BE FELT AS EARLY AS MID-MORNING AT RHI BUT UNCERTAINTY OF TIMING IS RATHER HIGH. ANY STORMS ARE NOT EXPECTED TO REACH INTO CENTRAL OR EAST-CENTRAL WI TAF SITES UNTIL LATE IN THE DAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ML AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1154 PM CDT FRI AUG 7 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 312 PM CDT FRI AUG 7 2015 SEVERAL CONCERNS WITH THE FORECAST DURING THIS PERIOD. THE FIRST COMES TONIGHT AND WHETHER THERE WILL BE ANY VALLEY FOG OR NOT. IN FAVOR OF THE FOG FORMING IS THE LITTLE BIT OF RAIN THIS MORNING AND THE CLOUDS THAT HAVE TRAPPED THIS MOISTURE. THE 07.12Z NAM IS THE MOST AGGRESSIVE WITH SHOWING SATURATION OCCURRING AT THE SURFACE FOR THE VALLEY LOCATIONS. THE NAM ALSO HAS THE MOST AMOUNT OF WIND JUST ABOVE THE SURFACE FOR MORE MIXING...WHICH GOES AGAINST FOG FORMATION. 07.17Z RAP SOUNDINGS WHILE HAVING A DEEPER LAYER OF LIGHT WINDS...COMES CLOSE TO SATURATING AT THE SURFACE AND THEN REALLY DRIES OUT JUST ABOVE THE SURFACE. THE 07.12Z GFS IS EVEN DRIER THAN THE RAP...SO HAVE DOUBTS THAT THERE WILL BE A LOT OF FOG IN THE VALLEYS TONIGHT. ANOTHER COMPLICATING FACTOR COULD BE THE INCREASE IN HIGH LEVEL CLOUDS FOR LATE TONIGHT AHEAD OF AN APPROACHING SHORT WAVE TROUGH. PATCHY VALLEY FOG WAS ALREADY IN THE FORECAST AND DO NOT PLAN TO MAKE ANY CHANGES TO THIS. WITH THE APPROACHING SHORT WAVE TROUGH...THE GFS SEEMS TO HAVE THE MOST SUPPORT FROM THE OTHER MODELS WITH THE 07.12Z ECMWF LOOKING SIMILAR ALONG WITH THE 07.12Z HI-RES ARW AND NMM. WATER VAPOR SATELLITE INDICATES THIS WAVE IS COMING OUT OF THE ROCKIES OVER EASTERN WYOMING AND NORTHERN COLORADO THIS AFTERNOON AND SHOULD THEN TRACK EAST ACROSS IOWA INTO SOUTHERN WISCONSIN AND NORTHERN ILLINOIS BY LATE SATURDAY MORNING. THE GFS SUGGESTS THIS WAVE WILL PRODUCE SOME WEAK TO MODERATE PV ADVECTION IN THE 500-300 MB LAYER ACROSS NORTHEAST IOWA INTO FAR SOUTHERN WISCONSIN LATE TONIGHT INTO EARLY SATURDAY MORNING. THE BOUNDARY THAT WENT THROUGH TODAY SHOULD BE HUNG UP OVER CENTRAL IOWA AND IT IS EXPECTED THAT WEAK TO MODERATE FRONTOGENESIS WILL OCCUR NORTH OF THIS BOUNDARY. THE BEST ISENTROPIC UP GLIDE ON THE 310K SURFACE IS EXPECTED TO REMAIN SOUTH OF THE BOUNDARY ACROSS CENTRAL AND SOUTHERN IOWA WITH POSSIBLY 1 TO 2 UBAR/S OVER NORTHEAST IOWA. THE GENERAL CONSENSUS AMONG THE MODELS IS THAT A COMPLEX OF SHOWERS AND STORMS SHOULD FORM OVER NEBRASKA TONIGHT AND MOVE EAST ALONG AND NORTH OF THE BOUNDARY. THE GFS AND HI-RES ARW AND NMM WOULD SUGGEST THERE IS AT LEAST A CHANCE THAT THIS COMPLEX SURVIVES LONG ENOUGH TO GET INTO THE SOUTHERN PARTS OF THE FORECAST AREA WHILE THE 07.12Z ECMWF STARTS TO DISSIPATE THE COMPLEX AND ONLY BRINGS IN SOME REMAINS SATURDAY AFTERNOON ACROSS THE SOUTH. WILL BRING IN SOME 20 TO 40 PERCENT CHANCES ACROSS NORTHEAST IOWA SATURDAY MORNING FOR THIS COMPLEX. ANOTHER SHORT WAVE TROUGH IS THEN EXPECTED TO COME OUT OF THE ROCKIES AND TRACK ACROSS THE REGION SATURDAY NIGHT. THE TRACK AND FORCING LOOK TO BE VERY SIMILAR TO THE WAVE FOR LATE TONIGHT INTO SATURDAY MORNING WITH THE EXCEPTION THAT THE SURFACE BOUNDARY SHOULD GET PUSHED FARTHER SOUTH INTO SOUTHERN IOWA OR NORTHERN MISSOURI. THE COMPLEX OF STORMS WITH THIS NEXT WAVE IS EXPECTED TO FORM OVER SOUTHWEST IOWA AND THEN TRACK EAST AND SHOULD LARGELY STAY TO THE SOUTH OF THE FORECAST AREA. THE GFS IS SLIGHTLY FARTHER NORTH THAN THE ECMWF AND TO HONOR THIS WILL HAVE SOME 20 TO 40 PERCENT CHANCES FROM ABOUT INTERSTATE 90 SOUTH. BY SUNDAY NIGHT THE MEAN RIDGE WILL BE TRYING TO BUILD OVER THE ROCKIES WITH AN UPPER LEVEL LOW OVER NORTHERN ONTARIO. THIS WILL START TO SET UP A NORTHWEST FLOW OVER THE REGION WITH THE POSSIBILITY OF A WEAK SHORT WAVE TROUGH ROTATING AROUND THE UPPER LEVEL LOW AND ACROSS THE AREA. THE FORCING WITH THIS WAVE LOOKS TO BE RATHER WEAK...BUT IT COULD PUSH A WEAK SURFACE BOUNDARY INTO THE AREA WITH THE POSSIBILITY OF SOME ACTIVITY ALONG IT. WILL CARRY SOME 30 TO 40 PERCENT CHANCES SUNDAY FOR THIS FEATURE WITH SOME LINGERING 20 TO 30 PERCENT CHANCES INTO SUNDAY NIGHT. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 312 PM CDT FRI AUG 7 2015 ONCE THE SHORT WAVE TROUGH FROM SUNDAY NIGHT EXITS THE AREA...A LARGE AREA OF HIGH PRESSURE WILL BUILD IN OVER THE UPPER MIDWEST. THIS HIGH LOOKS TO DOMINATE THE REGION FROM MONDAY NIGHT THROUGH WEDNESDAY NIGHT. THE ECMWF WOULD SUGGESTS IT HOLDS TIGHT OVER THE REGION THROUGH THE END OF THE WEEK WHILE THE GFS BRINGS A COLD FRONT ACROSS THE UPPER MIDWEST THURSDAY THROUGH FRIDAY. WILL JUST CARRY SOME LOW 20 TO 30 PERCENT RAIN CHANCES LATE IN THE PERIOD TO HONOR THE GFS SOLUTION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1154 PM CDT FRI AUG 7 2015 STILL HAVE SOME CONCERN ABOUT VALLEY FOG AFFECTING KLSE OVERNIGHT. THE TEMPERATURE/DEW POINT DEPARTURE IS CURRENTLY 4 DEGREES AND THE WINDS ARE CALM AT THE OFFICE. THIS WOULD BE FAVORABLE FOR VALLEY FOG. HOWEVER SOME MID TO HIGH LEVEL DEBRIS CLOUDS /FROM CONVECTION IN THE DAKOTAS/ WILL BE MOVING SOUTHEAST INTO THE AREA TONIGHT AND THE COMBINATION OF THESE CLOUDS ALONG WITH INCREASING WINDS ALOFT MAY INHIBIT VALLEY FOG. DUE TO THIS...JUST OPTED TO ADD BCFG TO THE TAF BETWEEN 08.10Z AND 08.14Z. ON SATURDAY AND SATURDAY EVENING...A SHORT WAVE TROUGH MOVING EAST ACROSS IOWA WILL KEEP MID CLOUDS ACROSS THE AREA THROUGH THIS TIME PERIOD. WINDS THROUGHOUT THE PERIOD WILL BE SOUTHERLY AND LESS THAN 10 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS RENO NV
230 AM PDT MON AUG 10 2015 .SYNOPSIS... WEAK LOW PRESSURE WILL MOVE THROUGH THIS MORNING WITH A SLIGHT CHANCE OF THUNDERSTORMS NORTH OF INTERSTATE 80. SOUTH FLOW THEN RESUMES MONDAY AFTERNOON AS LOW PRESSURE DROPS OFF THE WEST COAST. DRY CONDITIONS WITH TYPICAL AFTERNOON BREEZES AND NEAR NORMAL TEMPERATURES ARE EXPECTED. WINDY CONDITIONS ARE POSSIBLE THURSDAY AS THE LOW MOVES INTO OREGON. && .SHORT TERM... WATER VAPOR AND IR SATELLITE IMAGERY SHOW A DEFINED UPPER LEVEL DISTURBANCE MOVING INTO THE CALIFORNIA INTERIOR THIS MORNING. AS A RESULT, ISOLATED VIRGA SHOWERS HAVE FORMED NORTH OF THE TAHOE BASIN NORTHWARD INTO NORTHERN LASSEN COUNTY. THE HRRR AND NAM CONCUR THAT ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THROUGH MID MORNING TODAY AS THIS WAVE MOVES NORTHWARD. ANY THUNDERSTORMS THAT DO RESULT WILL BE DRY WITH DRY LIGHTNING THE PRIMARY THREAT. NEW FIRE STARTS WILL BE POSSIBLE, BUT COVERAGE OF CELLS DOES NOT WARRANT A RED FLAG WATCH OR WARNING. AS FOR CONSIDERATIONS INVOLVING THE ROUGH FIRE IN THE SOUTHERN SIERRA OF CALIFORNIA, HAVE EXTENDED AREAS OF SMOKE THROUGH MID MORNING IN SOUTHERN MONO COUNTY WITH HAZE PERSISTING INTO THE AFTERNOON. FIRE ACTIVITY THIS MORNING WILL DETERMINE WHETHER OR NOT THESE CONDITIONS PERSIST INTO TUESDAY. OTHERWISE, LOW PRESSURE DEEPENS AND DROPS SOUTH IN THE EASTERN PACIFIC WITH HIGH PRESSURE LOCATED OVER THE WESTERN PLAINS OF THE UNITED STATES. THIS LEAVES THE SIERRA AND WESTERN NEVADA IN A NEUTRAL PRESSURE ADVECTION REGION RESULTING IN GENERALLY BENIGN WEATHER CONDITIONS. MOISTURE TRANSPORT VECTORS ARE NOT FAVORABLE FOR A MONSOONAL MOISTURE SURGE AT THIS TIME. THE MOST SIGNIFICANT IMPACTS THROUGH MID WEEK WILL COME FROM DRIER SOUTH TO WESTERLY FLOW EACH AFTERNOON WITH LOCALLY BREEZY CONDITIONS FROM TYPICAL AFTERNOON ZEPHYRS. AS SEEN WITH THE ROUGH FIRE IN THE SOUTHERN SIERRA OF CALIFORNIA, THESE WINDS AND DRY CONDITIONS COULD ACTIVATE HOLDOVERS ALLOWING FOR RAPID FIRE GROWTH. BOYD .LONG TERM...THURSDAY THROUGH SUNDAY... MEDIUM RANGE OPERATIONAL MODELS ARE IN GOOD AGREEMENT AGAIN THIS CYCLE THROUGH EARLY SATURDAY. AFTER THAT DIFFERENCES APPEAR...AS THEY HAVE BEEN DOING SO FOR THE PAST FEW DAYS. UPPER LOW MOVES INTO THE PAC NW ON THURSDAY WITH STRONG LOW LEVEL PRESSURE AND THERMAL GRADIENTS OVER THE NORTHERN PART OF THE FORECAST AREA NORTH INTO OREGON. THESE STRONG GRADIENTS SHOULD DRIVE GUSTY WEST TO SOUTHWEST WINDS OVER THE NORTHERN 2/3RDS OF THE FORECAST AREA THURSDAY AFTERNOON AND EVENING. INCREASED MIXING WILL PUSH TEMPS AT OR ABOVE AVERAGE FOR ALL BUT THE FAR NORTHERN FORECAST AREA AND HUMIDITY VALUES SHOULD BE FAIRLY LOW. THIS COMBINATION WILL LIKELY PRODUCE CRITICAL FIRE WEATHER CONDITIONS FOR AT LEAST THE AREA NORTH OF HIGHWAY 50. UPPER LOW MOVES EAST FRIDAY WITH A LESSENING OF THE GRADIENT AND ATTENDANT WINDS. TEMPS WILL ALSO DECREASE OVER FAR NORTHERN AREAS OF THE CWA. DRY SOUTHWEST FLOW WILL KEEP ANY MENTION OF PCPN OUT OF THE FORECAST THROUGH AT LEAST SATURDAY. THE OPERATIONAL MODELS START TO DIVERGE SATURDAY WITH THE GFS HOLDING ON TO THE TROUGH A BIT LONGER WHILE THE ECMWF STARTS TO WEAKEN THE TROUGH AND BUILD A FLAT RIDGE. BY SUNDAY THE ECMWF IS MORE AGGRESSIVE BUILDING THE RIDGE AND THE GFS MAINTAINS A WEAK TROUGH. THE GEFS ENSEMBLE MEMBERS SHOW SOME SUPPORT FOR BOTH SOLUTIONS SO A COMPROMISE WAS MADE. THIS MEANT KEEPING THE HIGH TEMPS BELOW THE ECMWF GUIDANCE FOR SATURDAY AND SUNDAY. NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST. IF THE ECMWF SOLUTION IS MORE CORRECT THEN WE MIGHT SEE AND OUTSIDE CHANCE AT WEAK CONVECTION OVER THE FAR SOUTHERN CWA BY SUNDAY AS LIGHT UPSLOPE FLOW BRINGS A BIT MORE MOISTURE BACK TO THE REGION. OTHERWISE DRY WITH NEAR SEASONAL TEMPERATURES FOR THE EXTENDED PERIOD AND TYPICAL AFTERNOON WINDS ONCE WE GET PAST THURSDAY. 20 && .AVIATION... A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE EARLY THIS MORNING NORTH OF INTERSTATE 80 AS AN UPPER LEVEL WAVE OF LOW PRESSURE MOVES NORTH. OUTSIDE OF THE WAVE THERE SHOULD BE VFR CONDITIONS TODAY. TYPICAL SUMMER AFTERNOON WINDS ARE LIKELY TODAY WITH GUSTS EAST OF THE SIERRA IN THE 20-25 KT RANGE. HAZE AND SMOKE FROM CALIFORNIA FIRES WILL PRODUCE PERIODS OF LOWERED VISIBILITY TODAY AND TUESDAY. FAIRLY LIGHT WINDS TUESDAY. RIDGE WINDS BEGIN TO INCREASE WEDNESDAY AND THEN GUSTY WINDS DEVELOP THURSDAY AHEAD OF A SURFACE BOUNDARY THAT MOVES THROUGH THURSDAY NIGHT. INCREASED TURBULENCE IS HIGHLY PROBABLE FROM LATE WEDNESDAY THROUGH THURSDAY. 20 && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1148 PM MDT SUN AUG 9 2015 .SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT) ISSUED AT 302 PM MDT SUN AUG 9 2015 SIGNIFICANTLY DRIER AIR WILL REMAIN OVER THE AREA OVERNIGHT. THE 12Z KGJT SOUNDING HAD PRECIPITABLE WATER OF 0.63 IN. DEWPOINTS WILL CONTINUE TO DROP INTO THE 40S AND EVEN UPPER 30S AT SOME LOCATIONS. CAPE VALUES ARE PROJECTED IN THE RAP13 AND HRRR TO REMAIN LOW AS WELL...SO CONVECTION EARLY THIS EVENING WILL BE WEAK AND ONLY OVER AND DOWNWIND OF RIDGES. ONLY LIGHT PRECIPITATION IS EXPECTED WITH THESE STORMS ALONG WITH GUSTY WINDS. THUNDERSTORMS SHOULD DISSIPATE WELL BEFORE MIDNIGHT WITH NEARLY CLEAR SKIES EXPECTED AGAIN OVERNIGHT. MOISTURE BEGINS TO INCREASE FROM THE SOUTH AGAIN ON MONDAY...SO EXPECTING SCATTERED ACTIVITY IN THE SAN JUANS MONDAY EVENING AS THE 12Z NAM AND GFS INDICATE A H5 VORTICITY MAX REACHING THE FOUR CORNERS MONDAY EVENING. THE EURO IS A BIT SLOWER WITH THIS ENERGY...BUT IN ANY CASE IT DOES LOOK LIKE SHOWERS AND ISO TSTORMS WILL CONTINUE THROUGH THE OVERNIGHT HOURS ON MONDAY NIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 302 PM MDT SUN AUG 9 2015 TUESDAY MORNING WILL BE A MUGGY ONE...WITH CLOUD COVER AND RAIN SHOWERS ACROSS MUCH OF THE REGION BY MIDDAY. MONSOONAL MOISTURE WILL BE AT ITS HIGHEST THIS WEEK ON TUESDAY AFTERNOON AS PRECIPITABLE WATER VALUES ACROSS THE FOUR CORNERS REACH UPWARDS OF 1.2 INCHES AND MORE THAN 0.75 INCHES REACHING THE UT/CO/WY BORDER. THOUGH DEEP MOISTURE WILL BE IN PLACE...NOT FEELING VERY CONFIDENT ON THE THREAT OF FLASH FLOODING SINCE WE WILL LIKELY BE DEALING WITH WIDESPREAD CLOUD COVER AGAIN AND LACK OF LIFTING DUE TO DAYTIME HEATING. LOCALIZED FLASH FLOODING COULD OCCUR IF THERE IS SOME CLEARING WHICH PRODUCES ENOUGH LIFT FOR MORE VERTICALLY SUPPORTED THUNDERSTORMS. WEDNESDAY WILL LIKELY BE MORE OF A THREAT DAY FOR FLASH FLOODING WITH SKY CONDITIONS LESS CLOUDY BUT WITH DEEP MOISTURE STILL IN PLACE. FORECAST CONVECTIVE INDICES ON THE NAM ARE MORE FAVORABLE FOR HEAVY RAIN PRODUCING THUNDERSTORMS ON WEDNESDAY THAN TUESDAY...SO THESE DAYS WILL NEED TO BE WATCHED FOR POTENTIAL IMPACTS. THE LACK OF JET SUPPORT WILL KEEP STEERING WINDS LIGHT THROUGH THE END OF THE WEEK SO ANY SHOWERS AND STORMS WHICH DEVELOP WILL MOVE SLOWLY. SOME DRYING OCCURS LATER IN THE WORK WEEK DUE TO HIGH PRESSURE AMPLIFYING OVER THE ROCKIES...BUT PRECIPITABLE WATER VALUES REMAIN NEAR THREE QUARTERS OF AN INCH SO DIURNALLY INDUCED SHOWERS AND THUNDERSTORMS WILL DEVELOP EVERYDAY OVER HIGHER TERRAIN. NEXT SATURDAY...A TROUGH OVER THE PACIFIC NORTHWEST IS PROGGED TO MOVE INLAND NORTH OF COLORADO. THE INTERACTION OF THIS TROUGH WITH THE HIGH PRESSURE IN PLACE OVER THE ROCKIES WILL DRIVE A 50 KT JET INTO NE UTAH AND NW COLORADO AND POTENTIALLY CREATE MORE CONVECTIVE ACTIVITY UP NORTH NEXT WEEKEND. BUMPED HIGH TEMPS UP A COUPLE OF DEGREES IN THE LOWER VALLEYS TOWARD THE END OF THE WEEK CLOSER TO MOS GUIDANCE FOR A MIDDLE GROUND SOLUTION. FEEL THAT MOS GUIDANCE IS TOO HOT BUT PREVIOUS FORECAST WAS TOO LOW CONSIDERING THE EXPECTED AMOUNT OF SUNSHINE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1142 PM MDT SUN AUG 9 2015 EXPECT VFR CONDITIONS THROUGH MONDAY MORNING ACROSS THE REGION. INCREASING MOISTURE FROM THE SOUTH WILL BRING ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS SPREADING SOUTH TO NORTH LATE MONDAY AFTERNOON AND CONTINUING MONDAY NIGHT. THE BEST FOCUS WILL BE OVER SOUTHWESTERN COLORADO AND SOUTHERN AND CENTRAL MOUNTAIN LOCATIONS. STRONGER CELLS WILL HAVE CIGS OBSCURING MOUNTAIN TOPS BY LATE MONDAY. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...CC/JAM LONG TERM...JAM AVIATION...MPM
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
345 AM EDT MON AUG 10 2015 .DISCUSSION... TODAY-TONIGHT... POPS WELL BLO CLIMO AVG IN THE WAKE OF A DISSIPATING FRONTAL BOUNDARY OVER S FL/NRN BAHAMAS. THE TROF WILL COMBINE WITH A NARROW H100-H70 HI PRES RIDGE SPANNING THE ERN SEABOARD TO GENERATE A DEEP NERLY FLOW REGIME OVER THE FL PENINSULA. PATTERNS SUCH AS THIS ONE ARE ONE OF THE MOST STABLE FOR CENTRAL FL...AND THIS ONE WILL BE NO DIFFERENT. A MID LVL THERMAL RIDGE ASSOCD WITH THE RIDGE CURRENTLY BLANKETS MUCH CENTRAL FL WITH H70 TEMPS BTWN 9-10C AND H50 TEMPS ARND -5C... YIELDING AVG LAPSE RATES ARND 5.5C/KM THRU THE LYR. H85-H70 LAPSE RATES ARE NO BETTER WITH VALUES ARND 5C/KM. THE 00Z RAOBS AT KJAX/KXMR SHOW PWAT VALUES BTWN 1.6"-1.7"...WHILE RAP ANALYSIS INDICATES H100-H70 MEAN RH VALUES STRUGGLING TO HOLD THE 70PCT LINE...H85-H50 VALUES LARGELY ARND 40PCT. AVAILABLE MOISTURE IS SUFFICIENT TO SUPPORT ISOLD CONVECTION...AS RADAR TREND HAS SHOWN OVER THE PAST SVRL HRS OVER THE ATLC WATERS... BUT LITTLE MORE. FURTHERMORE...THE ONSHORE FLOW WILL PROMOTE THE EARLY FORMATION OF THE EAST COAST SEA BREEZE THAT WILL FAVOR THE W FL PENINSULA FOR DIURNAL CONVECTION...POPS AOB 20PCT. SEA BREEZE KEEP COASTAL TEMPS IN THE U80S...INTERIOR TEMPS IN THE L90S. MIN TEMPS IN THE L/M70S. A BROADLY WEAK BERMUDA RIDGE WL ATTEMPT TO BECOME RE-ESTABLISHED NEAR CENTRAL FL DURING TUE. THE FEATURE WL BE NUDGED SWD HOWEVER BY AN APCHG SHORTWAVE OVERNIGHT AND INTO WED. INCRSG RAIN CHCS WL OCCUR AT MIDWEEK WITH UPR TROUGH AND ASCD SFC BOUNDARY MOVING INTO N FL DURING WED...INCRSG LOCAL MOISTURE AND LIKELIHOOD OF AFTN SHOWERS AND STORMS ACROSS THE AREA. SLIGHTLY HIGHER RAIN CHCS ARE INDICATED OVER NORTHERN COUNTIES INTO THE OVERNIGHT PERIOD WHEN BOUNDARY IS ADVERTISED STALLING NORTH OF CENTRAL FL. THE WEAKENING BOUNDARY WI LINGER OVER N FL INTO LATE WEEK WITH AMPLE LAYER MOISTURE ACROSS THE REGION ALONG WITH FAVORABLE STEERING REGIME TO PRODUCE SCT TO NMRS DIURNAL SHOWERS AND SLOW MOVING STORMS. A GENERALLY WEAK PRESSURE PATTERN WL PREVAIL FROM THE WEEKEND INTO NEXT WEEK BRINGING HIGHER THAN NORMAL RAIN COVERAGE AT LEAST INTO EARLY NEXT WEEK. && .AVIATION...THRU 11/12Z WINDS: THRU 10/14Z...NE AOB 4KTS. BTWN 10/14Z-10/16Z...E/NE 7-10KTS CONTG THRU 11/02Z. BTWN 11/02Z-11/04Z...BCMG VRBL AOB 3KTS. VSBY/WX/CIGS: THRU 10/12Z...PTCHY MVFR BR/LCL LIFR FG VCNTY KVRB/KFPR...BRIEF ISOLD MVFR SHRAS COASTAL SITES. BTWN 10/12Z- 10/16Z...ISOLD MVFR SHRAS COASTAL SITES. BTWN 10/16Z-10/24Z...ISOLD IFR TSRAS INTERIOR SITES. AFT 11/04Z...SLGT CHC MVFR SHRAS BTWN KTIX- KSUA. && .MARINE... TODAY-TONIGHT...WEAK PGRAD IN THE WAKE OF A DISSIPATING FRONTAL TROF WILL COMBINE WITH A HIGH PRES RIDGE OVER THE DEEP SOUTH TO GENERATE A LIGHT E/NE BREEZE TODAY...BCMG A LIGHT TO GENTLE S/SW BREEZE OVERNIGHT AS A NEW FRONTAL BOUNDARY WORKS ITS WAY INTO THE DEEP SOUTH. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE... MAINLY IN AN ERLY SWELL. PRESENCE OF A WEAK RIDGE OVER THE WATERS AT MIDWEEK WL PRODUCE FAVORABLE BOATING CONDITIONS WITH SEAS AROUND 2 FT OR LESS NEAR SHORE AND 2 TO 3 FT OVER THE OUTER WATERS. THESE SIMILAR CONDITIONS CAN BE EXPECTED INTO THE WEEKEND AS WELL WITH AN INCREASE IN STORMS NEAR THE IMMEDIATE COAST. && .PRELIMINARY POINT TEMPS/POPS... DAB 88 74 92 74 / 10 0 20 20 MCO 92 74 95 75 / 20 0 30 20 MLB 88 76 91 75 / 10 10 30 20 VRB 89 73 92 73 / 20 20 30 30 LEE 93 74 94 76 / 20 10 30 20 SFB 92 73 95 76 / 20 0 30 20 ORL 93 74 94 77 / 20 0 30 20 FPR 89 72 92 72 / 20 20 30 30 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM...BRAGAW LONG TERM....PENDERGRAST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
526 AM EDT MON AUG 10 2015 .SYNOPSIS... A PRESSURE RIDGE WILL PUSH FARTHER OFF THE COAST TODAY. MOISTURE WILL INCREASE IN THE FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL MOVE THROUGH THE AREA LATE TUESDAY AND TUESDAY NIGHT. NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE ASSOCIATED WITH THE FRONT. DRYING WITH A DIMINISHED SHOWER CHANCE WILL OCCUR BEHIND THE FRONT WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... THE RIDGE ALONG THE COAST WILL BE SHIFTING FARTHER OFFSHORE THROUGH TONIGHT. AN INCREASE IN MOISTURE SHOULD OCCUR IN A SOUTHERLY FLOW. THE MODELS INDICATE UPPER SUPPORT WILL OCCUR THROUGH TONIGHT WITH AN H5 DIFLUENT PATTERN. ENHANCED LIFT MAY OCCUR THIS MORNING AND TONIGHT AHEAD OF SHORTWAVE TROUGHS. BELIEVE A LEAD SHORTWAVE TROUGH WAS HELPING SUPPORT THE SCATTERED SHOWERS IN THE FORECAST AREA EARLY THIS MORNING. THE CONVECTION ALLOWING MODELS GENERALLY SHOWED SCATTERED SHOWER AND THUNDERSTORM COVERAGE TODAY AND THIS APPEARS REASONABLE WITH SHORTWAVE TROUGH TIMING NOT DIURNALLY FAVORABLE. THE GUIDANCE CONSENSUS MOS SUPPORTED POPS OF 20 TO 30 PERCENT TODAY. THE THUNDERSTORM CHANCE SHOULD INCREASE TONIGHT AHEAD OF THE NEXT SHORTWAVE TROUGH. THE HRRR DISPLAYED CONSIDERABLE COVERAGE ABOUT TO ENTER THE FORECAST AREA FROM THE WEST TOWARD SUNSET. THE SPC WRF SHOWED THIS AREA DIMINISHING AS IT MOVED THROUGH THE FORECAST AREA DURING THE 800 PM TO 100 AM TIME FRAME. FORECASTED A POP AROUND 40 PERCENT CLOSE TO THE GUIDANCE CONSENSUS. FOLLOWED THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE TODAY. LEANED TOWARD THE WARMER GUIDANCE BECAUSE OF EXPECTED CLOUDINESS AND MIXING TONIGHT. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... CONVERGENCE INTO A PRE-FRONTAL TROUGH AND COLD FRONT TUESDAY AND TUESDAY NIGHT PLUS UPPER-LEVEL TROUGHING SHOULD LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS TUESDAY AND TUESDAY NIGHT. WE LEANED TOWARD THE HIGHER POP GUIDANCE. SHOWER AND THUNDERSTORM COVERAGE MAY BE GREATEST EARLY TUESDAY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH AND AGAIN TUESDAY EVENING NEAR STRONGER CONVERGENCE JUST AHEAD OF THE FRONT. THE MODELS INDICATE MODERATE INSTABILITY AND PRECIPITABLE WATER OVER 2 INCHES. THUNDERSTORMS WITH DAMAGING WIND AND EXCESSIVE RAIN WILL BE POSSIBLE. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE GFS AND ECMWF INDICATE UPPER TROUGHING CONTINUING OVER THE EASTERN PART OF THE NATION THROUGH THE MEDIUM-RANGE PERIOD. THE MODELS DISPLAY A FRONTAL SYSTEM LINGERING NEAR THE SOUTHEAST COAST. DEEP MOISTURE APPEARS TO REMAIN SOUTH AND EAST OF THE FORECAST AREA. THE GFS AND ECMWF MOS HAVE TEMPERATURES NEAR CLIMATOLOGY WITH POPS 10 TO 30 PERCENT. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... A FEW SHOWERS HAVE DEVELOPED OVER THE WESTERN MIDLANDS AND CSRA EARLY THIS MORNING. GIVEN LATEST RADAR TRENDS...HAVE INCLUDED A TEMPO GROUP FOR SHOWERS FOR AGS/DNL UNTIL 12Z. CLOUDS AND A 15 TO 20 KNOT LOW LEVEL JET SHOULD LIMIT FOG POTENTIAL BEFORE SUNRISE. LIGHT SE WINDS EARLY BECOMING SOUTH TO SOUTHWEST 5 TO 10 KNOTS BY LATE MORNING. SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP ACROSS THE AREA BY EARLY THIS EVENING...BUT GIVEN LOW CONFIDENCE IN TIMING AND AREAL COVERAGE...HAVE NOT INCLUDED CONVECTION IN THE TAFS ATTM. EXTENDED AVIATION OUTLOOK...SHOWERS AND THUNDERSTORMS POSSIBLE TUESDAY THROUGH TUESDAY NIGHT AS AN APPROACHING FRONTAL BOUNDARY MOVES THROUGH THE REGION. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 99
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
413 AM EDT MON AUG 10 2015 .SHORT TERM /TODAY THROUGH TUESDAY/... A COLD FRONT WILL IMPACT THE CWFA IN THE SHORT TERM PORTION OF THE FORECAST AREA. THE FRONT CURRENTLY STRETCHES FROM THE MID MISSISSIPPI RIVER VALLEY TO THE TENNESSEE VALLEY. THE BOUNDARY WILL SLIP SLOWLY SOUTH TODAY...AND CROSS MUCH OF THE FORECAST AREA ON TUESDAY. DEWPOINTS HAVE BEGUN TO CREEP UP ACROSS THE CWFA...A SIGN OF INCREASING LOW LEVEL MOISTURE. PRECIPITATION CHANCES WILL INCREASE TODAY AHEAD OF THE FROPA. HI-RES MODELS ARE SHOWING A RATHER ORGANIZED LINE OF SHOWERS AND THUNDERSTORMS MOVING SOUTH ACROSS NORTH AND CENTRAL GA THIS AFTERNOON. THE LOCAL WRF AND THE HRRR DO DIFFER A BIT...WITH THE WRF BEING LATER WITH THE CONVECTION. HAVE TRIED TO COMPROMISE ON TIMING. BOTH MODELS...HOWEVER...INDICATE VERY GOOD RAIN CHANCES ACROSS NORTHERN GA TODAY. SO...HAVE RAISED POPS TO LIKELY IN THAT REGION. ATMOS WILL BE FAVORABLE FOR STRONG TO ISOLATED SEVERE STORMS. GOOD SURFACE INSTABILITY WILL BE PRESENT...WITH AN ASSIST BY A SHORTWAVE DROPPING SOUTH IN THE MID LEVEL FLOW. MODELS CURRENTLY KEEP LAPSE RATES FAIRLY WEAK...BUT THE SHORTWAVE WILL PROVIDE SOME LIFT. COPIOUS CLOUD COVER SHOULD HELP LIMIT SEVERE STORM COVERAGE. THE MAIN FOCUS FOR TODAYS CONVECTION SHOULD BE ANY OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES FROM THE THUNDERSTORM COMPLEX CURRENTLY ACROSS THE MID MISSISSIPPI RIVER VALLEY. THE ACTUAL FRONTAL BOUNDARY WILL PROVIDE A FOCUS FOR STORMS TOMORROW. TEMPS SHOULD BE A FEW DEGREES COOLER THAN YESTERDAYS VALUES DUE TO THE INCREASED CLOUD COVER. TEMP/DEWPOINT VALUES REMAIN BELOW CRITICAL THRESHOLDS FOR A HEAT ADVISORY AT THIS TIME. NLISTEMAA && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... GUIDANCE IN DECENT AGREEMENT WITH AFOREMENTIONED FRONTAL BOUNDARY IN THE SHORT TERM LINGERING ACROSS THE SOUTHERN TIER OF THE CWA FOR TUESDAY NIGHT INTO WEDNESDAY...THEN FINALLY PUSHING JUST SOUTH OF THE AREA AND BECOMING MORE DIFFUSE THRU THE REST OF THE WORK WEEK. HAVE TRENDED CHANCE TO SLIGHT POPS ACCORDINGLY AND ADVECTION OF ABNORMALLY DRY AIR IN FROM THE NW WILL ALLOW FOR A RATHER PLEASANT WED AND THURS WITH SLIGHTLY BELOW NORMAL HIGHS AND RESULTANT AFTERNOON RH VALUES IN THE 40S. FOR FRIDAY INTO THE WEEKEND...A BROAD/WEAK AREA OF LOW PRESSURE LOOKS TO DEVELOP ACROSS THE NORTHERN GOM ALLOWING FOR SOME LOW LEVEL MOISTURE TRANSPORT OFF THE ATLANTIC. HAVE CONTINUED TO ADVERTISE A RETURN OF SLIGHT TO LOW END CHANCE POPS FOR PORTIONS OF THE AREA...MAINLY FOR DIURNALLY DRIVEN CONVECTION. NO OTHER CLEAR FORCING MECHANISM LOOKS TO BE PRESENT SO NOT EXPECTING ANYTHING WIDESPREAD AND RATHER STAGNANT AIRMASS IN PLACE SO DEVELOPMENT SHOULD BE TYPICAL SUMMERTIME OUTFLOW DRIVEN. TEMPS SHOULD BE SLIGHTLY WARMER THAN MIDWEEK BUT CLOSE TO NORMAL OR SLIGHTLY BELOW WITH ENHANCED CLOUD COVERAGE. BAKER && .AVIATION... 06Z UPDATE... HIGH RES MODELS ARE BRINGING IN PRECIP A LITTLE EARLIER THAN PREVIOUS RUNS. HAVE PUSHED BACK THE PROB GROUP A COUPLE OF HOURS. CIGS AROUND 045 DURING THE AFTERNOON. MODEL SOUNDINGS ARE ALSO SHOWING SOME POTENTIAL FOR MVFR CIGS OVERNIGHT. //ATL CONFIDENCE...06Z UPDATE... MED CONFIDENCE ALL ELEMENTS. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 90 72 89 71 / 40 40 30 30 ATLANTA 90 74 88 72 / 40 40 30 20 BLAIRSVILLE 84 67 83 63 / 60 40 30 10 CARTERSVILLE 90 71 88 68 / 60 40 30 20 COLUMBUS 93 76 91 74 / 40 30 40 40 GAINESVILLE 87 72 87 71 / 60 40 30 20 MACON 92 74 90 73 / 40 30 40 40 ROME 91 72 89 68 / 60 40 30 10 PEACHTREE CITY 91 72 89 70 / 40 30 30 30 VIDALIA 92 73 92 74 / 30 20 40 50 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...NLISTEMAA LONG TERM....BAKER AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
305 AM CDT MON AUG 10 2015 .SHORT TERM...(TODAY) ISSUED AT 305 AM CDT MON AUG 10 2015 07Z/2AM SURFACE ANALYSIS SHOWS A 1010MB LOW OVER CENTRAL ILLINOIS...WITH A FRONTAL BOUNDARY EXTENDING SOUTHWESTWARD INTO THE OZARKS. A LARGE CLUSTER OF THUNDERSTORMS THAT DEVELOPED ALONG AN OLD OUTFLOW BOUNDARY IS ONGOING WELL SOUTH OF THE FRONT ACROSS SOUTHERN MISSOURI INTO FAR SOUTHERN ILLINOIS...HOWEVER THESE STORMS ARE DROPPING SOUTHWARD AWAY FROM THE KILX CWA. MEANWHILE...ANOTHER WEAK FRONT IS ANALYZED ACROSS CENTRAL IOWA WHERE A SECOND CLUSTER OF SHOWERS AND THUNDERSTORMS IS LOCATED. HRRR SUGGESTS THESE STORMS WILL WEAKEN AS THEY TRACK SLOWLY EASTWARD AND WILL NEVER REACH CENTRAL ILLINOIS. RAPIDLY WARMING CLOUD TOPS ON LATEST IR SATELLITE IMAGERY SUPPORT THIS THEORY...SO HAVE MAINTAINED A DRY FORECAST ACROSS THE ENTIRE AREA EARLY THIS MORNING. MAIN CONCERN EARLY ON WILL BE AREAS OF FOG THANKS TO AMPLE LOW-LEVEL MOISTURE...LIGHT WINDS...AND BREAKS IN THE OVERCAST. VISBYS HAVE OCCASIONALLY DROPPED TO AROUND 1/4 MILE ACROSS THE FAR NORTHERN CWA OVER THE PAST HOUR...SO WILL NEED TO MONITOR TRENDS CLOSELY FOR POTENTIAL DENSE FOG ADVISORY. AT THIS POINT...FOG HAS NOT BEEN CONSISTENTLY DENSE OR WIDESPREAD...SO WILL HOLD OFF ON AN ADVISORY. AS THE IOWA FRONT SAGS SOUTHEASTWARD...A FEW SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON DURING PEAK HEATING. WITH SURFACE DEWPOINTS REMAINING IN THE LOWER TO MIDDLE 70S...SBCAPE VALUES WILL REACH THE 1500 TO 2500J/KG RANGE. WEAK CONVERGENCE ALONG THE FRONT WILL BE ENOUGH TO TRIGGER WIDELY SCATTERED CONVECTION...PARTICULARLY ACROSS THE CENTRAL/NORTHERN CWA IN CLOSER PROXIMITY TO THE BOUNDARY. WILL CARRY 30 POPS ACROSS THIS AREA...TAPERING DOWN TO 20S ALONG/SOUTH OF I-70. && .LONG TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 305 AM CDT MON AUG 10 2015 ANY LINGERING SHOWERS/THUNDERSTORMS WILL QUICKLY DISSIPATE AFTER SUNSET AS DAYTIME INSTABILITY WANES. HAVE THEREFORE INCLUDED A 20 POP ACROSS THE BOARD THROUGH MID-EVENING...THEN HAVE GONE DRY OVERNIGHT. COOLER/LESS HUMID AIR WILL GRADUALLY TRICKLE SOUTHWARD INTO THE AREA TONIGHT THROUGH THURSDAY AS HIGH PRESSURE BUILDS INTO THE REGION. AFTERNOON HIGHS WILL BE IN THE LOWER TO MIDDLE 80S WHILE OVERNIGHT LOWS DROP INTO THE UPPER 50S AND LOWER 60S EACH DAY. AFTER THAT...MODELS CONTINUE TO ADVERTISE A WEAKENING COLD FRONT DROPPING INTO THE REGION LATE IN THE WEEK. BOTH THE GFS AND ECMWF ARE SLIGHTLY SLOWER WITH THE BOUNDARY THAN IN PRIOR RUNS...WITH THE FRONT REMAINING ACROSS NORTHERN ILLINOIS UNTIL FRIDAY NIGHT/SATURDAY. WITH PRONOUNCED UPPER RIDGE INITIALLY POSITIONED OVER THE PLAINS/SOUTHERN CANADA BUILDING EASTWARD...RISING UPPER HEIGHTS WILL CREATE AN UNFAVORABLE ENVIRONMENT FOR THE ALREADY WEAK FRONT. AS SUCH...BOTH MODELS SUGGEST IT WILL COMPLETELY DISSIPATE BEFORE PASSING THROUGH CENTRAL ILLINOIS. HAVE MAINTAINED JUST A SLIGHT CHANCE POP ALONG/NORTH OF I-74 ON FRIDAY IN CASE BOUNDARY CAN GET CLOSE ENOUGH TO TRIGGER ISOLATED STORMS...THEN HAVE RETURNED TO A DRY FORECAST FRIDAY NIGHT THROUGH SUNDAY AS FRONT WASHES OUT. TEMPERATURES OVER THE WEEKEND WILL CLIMB BACK INTO THE UPPER 80S TO AROUND 90 BEFORE THE NEXT FRONT POTENTIALLY COMES INTO THE PICTURE BY NEXT MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1100 PM CDT SUN AUG 9 2015 MAIN FORECAST CONCERN WILL BE CIGS AND VSBYS OVERNIGHT AS FOG BECOMES MORE WIDESPREAD. OVERALL...LITTLE CHANGE IN THINKING FROM EARLIER THIS EVENING. WIDELY SCATTERED SHOWERS WERE NOTED ALONG THE I-74 CORRIDOR WITH ANOTHER AREA OF SHOWERS AND STORMS SOUTH OF I-70. LATEST SURFACE ANALYSIS AND SURFACE OBSERVATIONS TO OUR WEST AND NORTHWEST STILL INDICATES SOME CLOUD COVER WHICH MAY PREVENT THE FOG FROM BECOMING TO WIDESPREAD EARLY MONDAY MORNING. HOWEVER...WE DO SEE SOME SIZEABLE BREAKS IN THE OVERCAST AS WELL SO ANY PROLONGED PERIOD OF CLEAR SKIES WILL LEAD TO SOME LOCALLY DENSE (IFR OR VLIFR CONDITIONS) FOG FOR A TIME EARLY MONDAY MORNING. THE FOG SHOULD BEGIN TO DISSIPATE BETWEEN 13-15Z MONDAY WITH CIGS GRADUALLY LIFTING TO LOW VFR CONDITIONS BY LATE MORNING WITH SCATTERED TO BROKEN CUMULUS IN THE AFTERNOON WITH BASES IN THE 3000-4000 FOOT RANGE. SURFACE WINDS WILL BE LIGHT AND VARIABLE TONIGHT AND THEN SWING INTO THE NORTHWEST TO NORTH MONDAY MORNING AT 10 TO 15 KTS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
259 AM CDT MON AUG 10 2015 .SHORT TERM... 219 PM CDT THROUGH MONDAY... THINKING THIS AFTERNOON AND EVENING WILL BE RELATIVELY QUIET AND POSSIBLY QUIETER THAN WHAT IS CURRENTLY FORECAST. STRAY SHOWERS ARE OUT OVER THE LAKE AND SOUTH OF I-80 NEAR OTTAWA AND OVER NW INDIANA. THE MCV FROM THIS MORNING/S COMPLEX IS SPINNING OVER WESTERN MO AND SOUTHERN IL BASED ON SATELLITE DATA WITH NEW CONVECTION FIRING OVER NORTHERN MO. THE LATEST RAP ANALYSIS INDICATES THERE IS ABOUT 500 J/KG OF CAPE OVER THE FAR SOUTHERN CWA WITH LITTLE TO NO CAPE OVER THE REST OF THE CWA. GUIDANCE IS STRUGGLING WITH WHERE CONVECTION WILL FIRE GOING INTO THIS AFTN AND HAVE LOW CONFIDENCE IN THE EXACT DETAILS MYSELF. THINKING THE MAJORITY OF CONVECTION WILL OCCUR TO THE WEST AND SOUTH OF THE CWA...BUT CANNOT RULE OUT A FEW SHOWERS AND/OR STORMS AS THE MCV SHIFTS EAST OVER SOUTHERN IL. LOWERED PRECIP CHANCES INTO THE CHANCE RANGE BELOW 50% AT BEST WITH THE HIGHEST VALUES SOUTH OF I- 80. WHILE STORMS MAY PRODUCE HEAVY DOWNPOURS AND A GUST OF WIND...SEVERE WEATHER IS NOT EXPECTED. ONCE AGAIN...AREAS NORTH OF I-88 MAY END UP BEING DRY BUT DID NOT HAVE ENOUGH CONFIDENCE TO GO DRY AT THIS TIME. LONG STORY SHORT...ISOLATED SHOWERS ARE POSSIBLE NORTH OF I-80 WITH ISOLATED TO SCATTERED SHOWERS AND A FEW STORMS SOUTH OF I-80. AS THE MCV SHIFTS EAST THIS EVENING...THE THREAT OF SHOWERS AND STORMS WILL ALSO SHIFT TO LOCATIONS ALONG AND EAST OF I-55. EXPECTING FOG TO DEVELOP OVERNIGHT AS WINDS DIMINISH AND SATURATED AIR COOLS. SOME AREAS MAY SEE DENSE FOG...VSBY OF 1/4 A MILE OR LESS...BUT AS OF RIGHT NOW EXPECTING MOSTLY AREAS OF FOG WITH VSBY GREATER THAN 1/4 OF A MILE. A SHORTWAVE TROUGH TRAVELS ACROSS WI TOMORROW WITH VORTICITY STREAMERS PASSING OVER FAR NORTHERN IL. THINKING SCATTERED SHOWERS AND STORMS WILL FORM ALONG THE VORT STREAMERS WITH BETTER COVERAGE NORTH OF I-80 ESPECIALLY ALONG THE WI/IL STATE LINE. THINKING COVERAGE WILL BE HIT OR MISS WITH PLENTY OF RAIN FREE HOURS. DID NOT MAKE MANY CHANGES TO HIGH TEMPS MONDAY WITH COOLER AIR SINKING IN FROM THE NORTH AND THICK CLOUD COVER. EXPECTING HIGHS AROUND 80 ALONG THE IL/WI STATE LINE AND ALONG THE LAKE WITH LOW TO MID 80S SOUTH OF I-80. JEE && .LONG TERM... MONDAY NIGHT THROUGH SUNDAY... 251 PM...MAIN FORECAST CONCERN IS THE CHANCE OF THUNDERSTORMS THURSDAY NIGHT THRU FRIDAY NIGHT. WEAK LOW PRESSURE IS EXPECTED TO BE EAST OF THE AREA AND MOVING ACROSS THE SOUTHERN GREAT LAKES REGION MONDAY EVENING. THERE IS A SLIGHT CHANCE OF AN EVENING SHOWER OR THUNDERSTORM BUT ANY ACTIVITY SHOULD BE QUICKLY DIMINISHING BY MID/LATE EVENING. HIGH PRESSURE THEN BUILDS ACROSS THE REGION TUESDAY AND WEDNESDAY. NORTHERLY WINDS MAY BE A BIT BREEZY NEAR THE LAKE INTO NORTHWEST INDIANA TUESDAY WITH THE CENTER OF THE HIGH STILL WEST OF THE AREA WITH CONTINUED LIGHTER NORTHERLY WINDS ON WEDNESDAY...WITH COOLER TEMPS AT THE LAKESHORE BOTH DAYS. WEDNESDAY NIGHT/THURSDAY MORNING WILL BE A BIT COOLER WITH LOWS POSSIBLY IN THE MID/UPPER 50S AWAY FROM THE URBAN AREAS. BUT AS THE HIGH SHIFTS EAST THURSDAY...WARMER SOUTHWESTERLY FLOW WILL RETURN WITH WINDS PERHAPS BECOMING BREEZY THURSDAY AFTERNOON. HIGHS WILL LIKELY REBOUND INTO THE MID 80S THOUGH STILL SOME DIFFERENCES REGARDING HOW MUCH WARMER TEMPS COULD BECOME. DIFFERENCES BEGIN TO SHOW UP FRIDAY AND FRIDAY NIGHT WITH THE GFS BRINGING A FRONTAL BOUNDARY ACROSS THE AREA FRIDAY AFTERNOON/ EVENING WHILE THE ECMWF KEEPS THIS FRONT NORTH OF THE CWA. A LITTLE TOO EARLY TO DETERMINE SPECIFICS BUT GRADIENT APPEARS LIGHT ENOUGH THAT A LAKE BREEZE IS POSSIBLE FRIDAY AFTERNOON. PRECIP CHANCES WILL LIKELY DEPEND ON HOW MUCH OF THE FRONTAL BOUNDARY REACHES THE AREA. HAVE LOW CHANCE POPS FOR NOW...BUT CONFIDENCE IS FAIRLY LOW. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * GRADUAL LOWERING OF CIG/VIS THROUGH MVFR/IFR OVERNIGHT. A FEW SPOTTY SHOWERS POSSIBLE. IMPROVEMENT FROM IFR/MVFR EXPECTED DURING MONDAY MORNING. * NORTHERLY WINDS MONDAY...LIKELY BECOMING NORTHEAST WITH LAKE BREEZE DURING THE AFTERNOON. * SCATTERED TSRA MONDAY AFTERNOON. KMD //DISCUSSION...UPDATED 06Z... A FEW LOW TOPPED SHOWERS IN COOK COUNTY AND OVER THE LAKE IN MOIST SW FLOW ATOP A LINGERING ELEVATED FRONT. CARRYING A VCSH FOR THESE FOR THE NEXT FEW HOURS BUT SHOULD BE LOW IMPACT. OVERNIGHT CONCERN FOCUSES ON CEILING AND VISIBILITY. DETERIORATION OF CONDITIONS HAD BEEN SLOW GOING BUT THE DOWNWARD TREND IS PICKING UP QUICKLY...ESPECIALLY IN OUTLYING AREAS WHERE SOME CLEARING SKIES HAVE ALLOWED CIGS AND VIS TO DROP INTO IFR AND EVEN LIFR. EXPECT THIS TREND TO CONTINUE AT LEAST FOR THE NEXT 4-6 HOURS BEFORE HIGHER CLOUDS BEGIN TO SPREAD OVERHEAD. MVFR CONDITIONS ARE ALSO MOVING INTO THE CHICAGOLAND TERMINALS. SLIGHTLY HIGHER DEWPOINT DEPRESSIONS MAY PRECLUDE IFR FROM GETTING TO ORD/MDW BUT WILL BE A CLOSE CALL. CONCERN SHIFTS TO SEVERAL ADDITIONAL PERIODS OF SHOWERS AND THUNDERSTORMS. TIMING OF THE SHORTWAVE OVER MINNESOTA BRINGS ACTIVITY THROUGH RFD BY 17Z AND THROUGH THE CHICAGO TERMINALS AROUND 18-20Z. HAVE CARRIED A VCTS FOR THIS TIME FRAME AS THERE SHOULD BE CAPE AROUND DUE TO THE MOIST AIR MASS AND INCREASED LAPSE RATES AHEAD OF THIS WAVE. FAVORABLE TIMING OF THE WAVE THOUGH SLIGHTLY EARLY...BUT SHOULD ALSO BE A CONVERGENT AXIS AS THE LAKE BREEZE BEGINS TO SETUP AS WELL. CARRIED A VCSH AFTER DUE TO THE FORCING POSSIBLY BEING THROUGH THE TERMINALS AND SLIGHTLY SHALLOWER MOISTURE AVAILABILITY. COVERAGE LOOKS TO BE SCATTERED AT THIS POINT. LASTLY...WINDS WILL SHIFT TO NORTHERLY MONDAY MORNING...THEN GAIN AN ONSHORE COMPONENT THROUGH THE MORNING/EARLY AFTERNOON AS THE LAKE INFLUENCE KICKS IN. AT THIS POINT MOST HI-RES GUIDANCE KEEPS WINDS UNDER 10 KT...THOUGH EXPECT A FEW GUSTS AT THE SENSORS TO GET CLOSE TO THAT THRESHOLD. KMD //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH IN WINDS. * MEDIUM IN CIG/VIS TRENDS TONIGHT/EARLY MONDAY. * MEDIUM-LOW IN MONDAY AFTERNOON TSRA. KMD //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY AND WEDNESDAY...VFR. NORTH-NORTHEAST WINDS. THURSDAY...VFR. SLIGHT CHANCE TSRA THURSDAY NGT. WEST-SOUTHWEST WINDS. FRIDAY...CHANCE TSRA. WEST-SOUTHWEST WINDS. SATURDAY...VFR. NORTHEAST WINDS. RATZER && .MARINE... 251 AM CDT LOW PRESSURE OVER NORTHERN ONTARIO WILL MOVE INTO QUEBEC BY THIS EVENING. THIS WILL ENABLE A TRAILING SURFACE TROUGH TO PASS OVER THE LAKE THIS MORNING AND SHIFT WINDS NORTHERLY. SEVERAL WEAK LOWS ALONG THE TROUGH AXIS WILL CONSOLIDATE INTO A SLIGHTLY DEEPER LOW OVER THE EASTERN GREAT LAKES. HIGH PRESSURE OVER THE NORTHERN PLAINS WILL SHIFT INTO UPPER MIDWEST TOMORROW. IN BETWEEN THESE TWO FEATURES...NORTHERLY WINDS WILL INCREASE TO 15-25 KTS BY TUESDAY MORNING. AS THE HIGH MOVES EAST...THESE NORTHERLY WINDS WILL SLOWLY DIMINISH TUESDAY NIGHT INTO WEDNESDAY. WINDS WILL SHIFT TO THE SOUTHWEST WEDNESDAY NIGHT AS THE HIGH SETTLES SOUTHEAST OF THE LAKE AND LOW PRESSURE APPROACHES HUDSON BAY. SPEEDS LOOK TO INCREASE INTO THE 15-25KT RANGE THURSDAY INTO THURSDAY NIGHT. HIGH PRESSURE WILL SHIFT WINDS BACK NORTHERLY TOWARD THE WEEKEND. KMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
123 AM CDT MON AUG 10 2015 .SHORT TERM... 219 PM CDT THROUGH MONDAY... THINKING THIS AFTERNOON AND EVENING WILL BE RELATIVELY QUIET AND POSSIBLY QUIETER THAN WHAT IS CURRENTLY FORECAST. STRAY SHOWERS ARE OUT OVER THE LAKE AND SOUTH OF I-80 NEAR OTTAWA AND OVER NW INDIANA. THE MCV FROM THIS MORNING/S COMPLEX IS SPINNING OVER WESTERN MO AND SOUTHERN IL BASED ON SATELLITE DATA WITH NEW CONVECTION FIRING OVER NORTHERN MO. THE LATEST RAP ANALYSIS INDICATES THERE IS ABOUT 500 J/KG OF CAPE OVER THE FAR SOUTHERN CWA WITH LITTLE TO NO CAPE OVER THE REST OF THE CWA. GUIDANCE IS STRUGGLING WITH WHERE CONVECTION WILL FIRE GOING INTO THIS AFTN AND HAVE LOW CONFIDENCE IN THE EXACT DETAILS MYSELF. THINKING THE MAJORITY OF CONVECTION WILL OCCUR TO THE WEST AND SOUTH OF THE CWA...BUT CANNOT RULE OUT A FEW SHOWERS AND/OR STORMS AS THE MCV SHIFTS EAST OVER SOUTHERN IL. LOWERED PRECIP CHANCES INTO THE CHANCE RANGE BELOW 50% AT BEST WITH THE HIGHEST VALUES SOUTH OF I- 80. WHILE STORMS MAY PRODUCE HEAVY DOWNPOURS AND A GUST OF WIND...SEVERE WEATHER IS NOT EXPECTED. ONCE AGAIN...AREAS NORTH OF I-88 MAY END UP BEING DRY BUT DID NOT HAVE ENOUGH CONFIDENCE TO GO DRY AT THIS TIME. LONG STORY SHORT...ISOLATED SHOWERS ARE POSSIBLE NORTH OF I-80 WITH ISOLATED TO SCATTERED SHOWERS AND A FEW STORMS SOUTH OF I-80. AS THE MCV SHIFTS EAST THIS EVENING...THE THREAT OF SHOWERS AND STORMS WILL ALSO SHIFT TO LOCATIONS ALONG AND EAST OF I-55. EXPECTING FOG TO DEVELOP OVERNIGHT AS WINDS DIMINISH AND SATURATED AIR COOLS. SOME AREAS MAY SEE DENSE FOG...VSBY OF 1/4 A MILE OR LESS...BUT AS OF RIGHT NOW EXPECTING MOSTLY AREAS OF FOG WITH VSBY GREATER THAN 1/4 OF A MILE. A SHORTWAVE TROUGH TRAVELS ACROSS WI TOMORROW WITH VORTICITY STREAMERS PASSING OVER FAR NORTHERN IL. THINKING SCATTERED SHOWERS AND STORMS WILL FORM ALONG THE VORT STREAMERS WITH BETTER COVERAGE NORTH OF I-80 ESPECIALLY ALONG THE WI/IL STATE LINE. THINKING COVERAGE WILL BE HIT OR MISS WITH PLENTY OF RAIN FREE HOURS. DID NOT MAKE MANY CHANGES TO HIGH TEMPS MONDAY WITH COOLER AIR SINKING IN FROM THE NORTH AND THICK CLOUD COVER. EXPECTING HIGHS AROUND 80 ALONG THE IL/WI STATE LINE AND ALONG THE LAKE WITH LOW TO MID 80S SOUTH OF I-80. JEE && .LONG TERM... MONDAY NIGHT THROUGH SUNDAY... 251 PM...MAIN FORECAST CONCERN IS THE CHANCE OF THUNDERSTORMS THURSDAY NIGHT THRU FRIDAY NIGHT. WEAK LOW PRESSURE IS EXPECTED TO BE EAST OF THE AREA AND MOVING ACROSS THE SOUTHERN GREAT LAKES REGION MONDAY EVENING. THERE IS A SLIGHT CHANCE OF AN EVENING SHOWER OR THUNDERSTORM BUT ANY ACTIVITY SHOULD BE QUICKLY DIMINISHING BY MID/LATE EVENING. HIGH PRESSURE THEN BUILDS ACROSS THE REGION TUESDAY AND WEDNESDAY. NORTHERLY WINDS MAY BE A BIT BREEZY NEAR THE LAKE INTO NORTHWEST INDIANA TUESDAY WITH THE CENTER OF THE HIGH STILL WEST OF THE AREA WITH CONTINUED LIGHTER NORTHERLY WINDS ON WEDNESDAY...WITH COOLER TEMPS AT THE LAKESHORE BOTH DAYS. WEDNESDAY NIGHT/THURSDAY MORNING WILL BE A BIT COOLER WITH LOWS POSSIBLY IN THE MID/UPPER 50S AWAY FROM THE URBAN AREAS. BUT AS THE HIGH SHIFTS EAST THURSDAY...WARMER SOUTHWESTERLY FLOW WILL RETURN WITH WINDS PERHAPS BECOMING BREEZY THURSDAY AFTERNOON. HIGHS WILL LIKELY REBOUND INTO THE MID 80S THOUGH STILL SOME DIFFERENCES REGARDING HOW MUCH WARMER TEMPS COULD BECOME. DIFFERENCES BEGIN TO SHOW UP FRIDAY AND FRIDAY NIGHT WITH THE GFS BRINGING A FRONTAL BOUNDARY ACROSS THE AREA FRIDAY AFTERNOON/ EVENING WHILE THE ECMWF KEEPS THIS FRONT NORTH OF THE CWA. A LITTLE TOO EARLY TO DETERMINE SPECIFICS BUT GRADIENT APPEARS LIGHT ENOUGH THAT A LAKE BREEZE IS POSSIBLE FRIDAY AFTERNOON. PRECIP CHANCES WILL LIKELY DEPEND ON HOW MUCH OF THE FRONTAL BOUNDARY REACHES THE AREA. HAVE LOW CHANCE POPS FOR NOW...BUT CONFIDENCE IS FAIRLY LOW. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * GRADUAL LOWERING OF CIG/VIS THROUGH MVFR/IFR OVERNIGHT. A FEW SPOTTY SHOWERS POSSIBLE. IMPROVEMENT FROM IFR/MVFR EXPECTED DURING MONDAY MORNING. * NORTHERLY WINDS MONDAY...LIKELY BECOMING NORTHEAST WITH LAKE BREEZE DURING THE AFTERNOON. * SCATTERED TSRA MONDAY AFTERNOON. KMD //DISCUSSION...UPDATED 06Z... A FEW LOW TOPPED SHOWERS IN COOK COUNTY AND OVER THE LAKE IN MOIST SW FLOW ATOP A LINGERING ELEVATED FRONT. CARRYING A VCSH FOR THESE FOR THE NEXT FEW HOURS BUT SHOULD BE LOW IMPACT. OVERNIGHT CONCERN FOCUSES ON CEILING AND VISIBILITY. DETERIORATION OF CONDITIONS HAD BEEN SLOW GOING BUT THE DOWNWARD TREND IS PICKING UP QUICKLY...ESPECIALLY IN OUTLYING AREAS WHERE SOME CLEARING SKIES HAVE ALLOWED CIGS AND VIS TO DROP INTO IFR AND EVEN LIFR. EXPECT THIS TREND TO CONTINUE AT LEAST FOR THE NEXT 4-6 HOURS BEFORE HIGHER CLOUDS BEGIN TO SPREAD OVERHEAD. MVFR CONDITIONS ARE ALSO MOVING INTO THE CHICAGOLAND TERMINALS. SLIGHTLY HIGHER DEWPOINT DEPRESSIONS MAY PRECLUDE IFR FROM GETTING TO ORD/MDW BUT WILL BE A CLOSE CALL. CONCERN SHIFTS TO SEVERAL ADDITIONAL PERIODS OF SHOWERS AND THUNDERSTORMS. TIMING OF THE SHORTWAVE OVER MINNESOTA BRINGS ACTIVITY THROUGH RFD BY 17Z AND THROUGH THE CHICAGO TERMINALS AROUND 18-20Z. HAVE CARRIED A VCTS FOR THIS TIME FRAME AS THERE SHOULD BE CAPE AROUND DUE TO THE MOIST AIR MASS AND INCREASED LAPSE RATES AHEAD OF THIS WAVE. FAVORABLE TIMING OF THE WAVE THOUGH SLIGHTLY EARLY...BUT SHOULD ALSO BE A CONVERGENT AXIS AS THE LAKE BREEZE BEGINS TO SETUP AS WELL. CARRIED A VCSH AFTER DUE TO THE FORCING POSSIBLY BEING THROUGH THE TERMINALS AND SLIGHTLY SHALLOWER MOISTURE AVAILABILITY. COVERAGE LOOKS TO BE SCATTERED AT THIS POINT. LASTLY...WINDS WILL SHIFT TO NORTHERLY MONDAY MORNING...THEN GAIN AN ONSHORE COMPONENT THROUGH THE MORNING/EARLY AFTERNOON AS THE LAKE INFLUENCE KICKS IN. AT THIS POINT MOST HI-RES GUIDANCE KEEPS WINDS UNDER 10 KT...THOUGH EXPECT A FEW GUSTS AT THE SENSORS TO GET CLOSE TO THAT THRESHOLD. KMD //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH IN WINDS. * MEDIUM IN CIG/VIS TRENDS TONIGHT/EARLY MONDAY. * MEDIUM-LOW IN MONDAY AFTERNOON TSRA. KMD //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY AND WEDNESDAY...VFR. NORTH-NORTHEAST WINDS. THURSDAY...VFR. SLIGHT CHANCE TSRA THURSDAY NGT. WEST-SOUTHWEST WINDS. FRIDAY...CHANCE TSRA. WEST-SOUTHWEST WINDS. SATURDAY...VFR. NORTHEAST WINDS. RATZER && .MARINE... 251 PM...LOW PRESSURE OVER NORTHERN ONTARIO WILL MOVE INTO QUEBEC BY MONDAY EVENING. A TRAILING COLD FRONT WILL MOVE ACROSS THE LAKE LATE TONIGHT INTO MONDAY MORNING SHIFTING WINDS NORTHERLY. ANOTHER WEAK LOW WILL MOVE SOUTH OF THE LAKE MONDAY AFTERNOON AS HIGH PRESSURE BUILDS INTO THE NORTHERN PLAINS. THE GRADIENT WILL TIGHTEN BETWEEN THESE TWO FEATURES WITH NORTHERLY WINDS INCREASING TO 15-25 KTS BY TUESDAY MORNING. AS THE HIGH MOVES EAST...THESE NORTHERLY WINDS WILL SLOWLY DIMINISH TUESDAY NIGHT INTO WEDNESDAY. WINDS WILL SHIFT TO THE SOUTHWEST WEDNESDAY NIGHT AS THE HIGH SETTLES SOUTHEAST OF THE LAKE AND DEPENDING ON HOW STRONG THE GRADIENT BECOMES...SPEEDS MAY INCREASE INTO THE 15-25KT RANGE THURSDAY INTO THURSDAY NIGHT. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1101 PM CDT SUN AUG 9 2015 .UPDATE... ISSUED AT 825 PM CDT SUN AUG 9 2015 THE BOUNDARY THAT WAS PRODUCED BY THE STORMS THIS MORNING WAS LOCATED OVER SOUTHEAST ILLINOIS BACK INTO EAST CENTRAL MISSOURI. A CLUSTER OF STORMS WAS TRACKING ESE ALONG THIS MESOSCALE FEATURE AND MAY CLIP OUR FAR SOUTHEAST COUNTIES. MEANWHILE...FURTHER TO THE NORTHWEST...A WEAK COOL FRONT WAS LOCATED FROM CENTRAL WISCONSIN SOUTHWEST THROUGH NORTHERN IOWA WITH A BAND OF STORMS OVER PARTS OF NORTHWEST IOWA. THE ACTUAL SYNOPTIC SCALE COOL FRONT TO OUR NORTHWEST IS FORECAST TO PUSH ACROSS THE FORECAST AREA MONDAY MORNING. UNTIL THEN...WILL CONTINUE WITH THE CHANCES FOR SHOWERS AND STORMS...ESPECIALLY ACROSS THE SOUTH OVERNIGHT WITH LOWER POPS AS YOU HEAD NORTH OF I-74. WITH THE ADDED MOISTURE FROM THE RAINFALL TODAY...LIGHT WINDS AND A GRADUAL TREND TOWARDS CLEARING SKIES LATE TONIGHT...FOG WILL BE A CONCERN AND WILL CONTINUE TO HOLD WITH THAT IN THE FORECAST THRU MONDAY MORNING. HAVE MADE SOME MINOR ADJUSTMENTS TO THE RAIN CHANCES...ESPECIALLY ACROSS THE NORTH AND MADE SOME TWEAKS TO THE SKY COVER FOR THE LATE NIGHT HOURS. WE SHOULD HAVE THE UPDATE OUT BY 845 PM. && .SHORT TERM...(TONIGHT) ISSUED AT 253 PM CDT SUN AUG 9 2015 BASED ON SURFACE DATA...APPEARS THERE IS A BOUNDARY STRETCHING FROM NORTHERN MO/SOUTHERN IA INTO NORTHERN PART OF CENTRAL IL. HOWEVER...THE EFFECTIVE BOUNDARY SHOULD BE MUCH FURTHER SOUTH AS A RESULT OF THE MCS THAT MOVED ACROSS THE AREA EARLIER THIS MORNING PUSHING IT SOUTH OF THE CWA. HRRR DOES NOT SHOW ANY PCPN IN THE CWA TONIGHT...BUT DOES HAVE THE SMALL AREA OF PCPN IN NORTHERN MO MOVING EAST-SOUTHEAST INTO SOUTHERN IL THIS EVENING. BUT WITH A WEAK CONVERGENT BOUNDARY IN THE AREA AM INCLINED TO KEEP A CHANCE FOR POPS IN THE FORECAST FOR TONIGHT. TREND SHOULD BE...AND MODELS DO SUPPORT THAT THIS WEAK BOUNDARY SHOULD MOVE SOUTH DURING THE OVERNIGHT PERIOD. SO CHANCE POPS SOUTHEAST OF THE ILLINOIS RIVER TONIGHT. ENDING OF PCPN CHANCES WILL START ALONG THE RIVER AND THEN PROGRESS SOUTHEAST THROUGH THE PERIOD. OTHER ISSUE OVERNIGHT WILL BE FOG DEVELOPMENT. WITH LOTS OF BREAKS IN THE CLOUDS THIS EVENING AND OVERNIGHT...COMBINED WITH THE ABUNDANCE OF LOW LEVEL MOISTURE FROM THE RAIN THIS MORNING...AND LIGHT WINDS...BELIEVE FOG WILL DEVELOP THIS EVENING AND CONTINUE INTO THE OVERNIGHT HOURS. SO HAVE INCLUDED AREAS OF FOG IN THE FORECAST THE NORTHERN AND CENTRAL PARTS OF THE AREA. ONLY PLACE WITHOUT ANY FOG WILL BE AREAS SOUTHEAST OF I-70. OVERNIGHT LOWS AROUND 70S LOOKS REASONABLE WITH COOLEST TEMPS UP NORTH WHERE MORE BREAKS IN CLOUDS SHOULD BE. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 253 PM CDT SUN AUG 9 2015 A FRONTAL BOUNDARY CURRENTLY FROM NORTHERN WISCONSIN TO NORTHERN NEBRASKA WILL PUSH INTO SOUTHEAST ILLINOIS BY MID MORNING MONDAY...AIDED BY SEVERAL AREAS OF THUNDERSTORM DEVELOPMENT AHEAD OF THE FRONT THIS EVENING INTO TONIGHT. THE EFFECTIVE FRONT WILL LIKELY BE LINGERING IN SOUTHEAST PORTIONS OF THE CENTRAL IL FORECAST AREA THROUGH THE MORNING AND HAVE CONTINUED PRECIPITATION CHANCES IN THAT AREA THROUGH NOON. MOST OF THE THUNDERSTORM ACTIVITY WILL TEND TO MOVE EASTWARD THROUGH THE DAY...HOWEVER AN UPPER LEVEL SHORTWAVE WILL APPROACH FROM THE NORTHWEST BY AFTERNOON...AND LIFT ASSOCIATED WITH THIS FEATURE WILL CAUSE CHANCES FOR SHOWERS AND THUNDERSTORMS TO RE-DEVELOP FOR AFTERNOON AND EARLY EVENING...MAINLY FROM THE ILLINOIS RIVER NORTHWESTWARD. HIGHS EXPECTED TO REACH FROM AROUND 81 IN GALESBURG TO THE MID 80S SPRINGFIELD TO PARIS SOUTHWARD WITH WINDS BECOMING NORTHWEST UP TO 10 MPH. AFTER THIS FEATURE PASSES THROUGH...DRY CONDITIONS ARE EXPECTED THROUGH MUCH OF THE WEEK AS A PRONOUNCED UPPER LEVEL RIDGE BUILDS OVER THE CENTRAL U.S. AND TROUGHING OVER THE NORTHEASTERN U.S. A COOL NORTHWEST FLOW PATTERN BETWEEN THE RIDGE AND TROUGH WILL BRING HIGH TEMPERATURES PRIMARILY IN THE LOW 80S AND LOWS IN THE LOW 60S THROUGH THURSDAY. A COLD FRONT EMBEDDED IN THIS FLOW PATTERN WILL DROP INTO THE GREAT LAKES/MIDWEST AREA FRIDAY. MODELS CONTINUE SOME RUN TO RUN INCONSISTENCIES FOR THIS FEATURE...BUT BULK OF GUIDANCE CONTINUES TO SUGGEST PRECIPITATION ASSOCIATED WITH THIS FEATURE MAY STRUGGLE TO REACH AS FAR SOUTHWEST AS CENTRAL ILLINOIS. THEREFORE...HAVE INCORPORATED SLIGHT CHANCES FOR THUNDERSTORMS MAINLY I-72 NORTHWARD. DRY CONDITIONS SHOULD THEN RETURN THROUGH THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1100 PM CDT SUN AUG 9 2015 MAIN FORECAST CONCERN WILL BE CIGS AND VSBYS OVERNIGHT AS FOG BECOMES MORE WIDESPREAD. OVERALL...LITTLE CHANGE IN THINKING FROM EARLIER THIS EVENING. WIDELY SCATTERED SHOWERS WERE NOTED ALONG THE I-74 CORRIDOR WITH ANOTHER AREA OF SHOWERS AND STORMS SOUTH OF I-70. LATEST SURFACE ANALYSIS AND SURFACE OBSERVATIONS TO OUR WEST AND NORTHWEST STILL INDICATES SOME CLOUD COVER WHICH MAY PREVENT THE FOG FROM BECOMING TO WIDESPREAD EARLY MONDAY MORNING. HOWEVER...WE DO SEE SOME SIZEABLE BREAKS IN THE OVERCAST AS WELL SO ANY PROLONGED PERIOD OF CLEAR SKIES WILL LEAD TO SOME LOCALLY DENSE (IFR OR VLIFR CONDITIONS) FOG FOR A TIME EARLY MONDAY MORNING. THE FOG SHOULD BEGIN TO DISSIPATE BETWEEN 13-15Z MONDAY WITH CIGS GRADUALLY LIFTING TO LOW VFR CONDITIONS BY LATE MORNING WITH SCATTERED TO BROKEN CUMULUS IN THE AFTERNOON WITH BASES IN THE 3000-4000 FOOT RANGE. SURFACE WINDS WILL BE LIGHT AND VARIABLE TONIGHT AND THEN SWING INTO THE NORTHWEST TO NORTH MONDAY MORNING AT 10 TO 15 KTS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SMITH SHORT TERM...AUTEN LONG TERM...ONTON AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
555 AM EDT MON AUG 10 2015 .SYNOPSIS... ISSUED AT 350 AM EDT MON AUG 10 2015 SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AS A LOW PRESSURE SYSTEM MOVES ACROSS THE REGION. A FEW OF THESE STORMS MAY PRODUCE HEAVY RAIN AND GUSTY WINDS ALONG AND EAST OF INTERSTATE 69 THIS AFTERNOON. HIGH PRESSURE AND DRY CONDITIONS RETURN OVERNIGHT AND PERSIST UNTIL THE END OF THE WEEK. ONE LAST MUGGY DAY TODAY WITH HIGHS AROUND 80 DEGREES BUT LESS HUMID AND SLIGHTLY COOLER CONDITIONS EXPECTED FOR THE REST OF THE WEEK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM EDT MON AUG 10 2015 ANOTHER "GRUNGY" DAY IN STORE FOR THE LOCAL FORECAST AREA AS BROAD MID/UPPER LEVEL HEIGHT FALLS INDUCE MODEST SURFACE CYCLOGENESIS OVER THE GREAT LAKES WITH A VERY MOIST/MARGINALLY UNSTABLE ENVIRONMENT IN PLACE. THIS SETUP WILL LIKELY LEAD TO SEVERAL ROUNDS OF SPORADIC SHOWERS AND A FEW EMBEDDED THUNDERSTORMS. ALREADY A FEW ISOLATED SHOWERS POPPING UP ACROSS THE REGION AND SHOULD SEE THIS ACTIVITY GRADUALLY EXPAND DURING THE DAY AS DIFFUSE SURFACE BOUNDARY CURRENTLY OVER IOWA PUSHES EASTWARD AND CAPITALIZES ON SOME DEGREE OF DIURNAL HEATING. LAST FEW RUNS OF HRRR (AND TO A LESSER EXTENT THE RAP) FINALLY SEEM TO HAVE A LITTLE BETTER HANDLE ON THE CURRENT PICTURE AND SUGGEST PRECIP WILL EXPAND IN OUR NORTHWEST COUNTIES DURING THE LATE MORNING (~14Z) AND PUSH SOUTHEASTWARD THROUGH THE DAY. THIS SEEMS REASONABLE BASED ON LATEST RADAR MOSAIC/SURFACE OBS AND BACKGROUND SYNOPTIC PATTERN. HAVE THEREFORE MASSAGED POP GRIDS A BIT TO REFLECT THIS EXPECTED EVOLUTION. MIDLEVEL LAPSE RATES DO GET A LITTLE BETTER WITH APPROACHING TROUGH AND AMPLE LOW LEVEL MOISTURE WILL SUPPORT AROUND 1500 J/KG OF SBCAPE IN OUR EASTERN HALF THIS AFTERNOON DESPITE ABUNDANT CLOUD COVER. THIS SHOULD BE ENOUGH FOR DECENT COVERAGE OF THUNDERSTORMS BUT POTENTIAL FOR STRONG UPDRAFTS AND SEVERE WEATHER APPEARS LOW. PASSING MIDLEVEL SPEED MAX DOES YIELD GOOD DEEP LAYER SHEAR NUMBERS BUT WIND PROFILES IN THE 0-3KM LAYER ARE FAIRLY LIGHT AND...GIVEN LESS THAN STELLAR INSTABILITY VALUES...SUGGEST A LOW SEVERE RISK. MAIN THREAT WOULD BE AN ISOLATED STRONG/SEVERE DOWNBURST WHERE ANY POCKETS OF ENHANCED CAPE MANAGE TO DEVELOP. POCKETS OF HEAVY RAIN ALSO POSSIBLE GIVEN PW VALUES AROUND 1.75 INCHES BUT RECENT DRY SPELL AND OVERALL LACKLUSTER SYNOPTIC FORCING SUGGEST THREAT FOR WIDESPREAD FLOODING IS LOW. PRECIP SHOULD EXIT THE CWA BY THIS EVENING WITH COOLER AND MUCH DRIER AIR FILTERING SOUTH. AFTER A MUGGY DAY TODAY WITH HIGHS AROUND 80F...EXPECT DEWPOINTS AND LOW TEMPS TO DROP BACK INTO THE LOWER 60S OVERNIGHT. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 350 AM EDT MON AUG 10 2015 HIGH PRESSURE OVER THE UPR MIDWEST TUE WILL MOVE SE TO INDIANA WED PROVIDING FAIR WEATHER ACROSS OUR AREA. NW FLOW ALOFT WILL ADVECT A COOL CANADIAN AIRMASS S-SE INTO OUR AREA RESULTING IN BLO NORMAL TEMPS THROUGH THIS TIMEFRAME. DRY WX SHOULD CONT THU AS THE HIGH MOVES SE OF THE AREA WITH WAA ON THE BACKSIDE OF THE HIGH RESULTING IN A LITTLE WARMER TEMPS. A CDFNT IS EXPECTED TO DROP SLOWLY S-SE ACROSS THE GRTLKS THU NGT- FRI NGT. UPR RIDGE AXIS OVER THE ROCKIES IS ALSO EXPECTED TO MOVE EAST IN THIS TIMEFRAME SO A GENERAL WKNG TREND OF THE FRONT IS EXPECTED... BUT MEDIUM RANGE MODELS IN DECENT AGREEMENT SUGGESTING AT LEAST SOME CONVECTION MAY FORM ALONG/AHEAD OF THE FRONT SO HAVE ADDED LOW POPS FOR LATE IN THE WORKWEEK. BY THE WEEKEND THE UPR RIDGE AXIS SHOULD MOVE OVER OUR AREA PROVIDING DRY WX WITH ABOVE NORMAL TEMPS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 555 AM EDT MON AUG 10 2015 SHOWERS AND THUNDERSTORMS WILL GRADUALLY INCREASE IN COVERAGE TODAY AS A MIDLEVEL TROUGH APPROACHES THE REGION AND INTERSECTS A VERY MOIST AIRMASS. ISOLATED THUNDERSTORMS POSSIBLE THIS MORNING BUT BETTER CHANCES STILL LOOK TO BE AT KFWA THIS AFTERNOON. PERIODS OF MVFR CONDITIONS POSSIBLE AS WEAK FRONTAL BOUNDARY APPROACHES THE AREA BUT LATEST HI-RES/RAPID UPDATE GUIDANCE SUGGESTS CEILINGS WILL LIKELY REMAIN ABOVE FUEL ALTERNATE CRITERIA. CONDITIONS WILL IMPROVE BY THIS EVENING AS FRONT EXITS AND DRIER AIR FILTERS SOUTH. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...JT AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
350 AM EDT MON AUG 10 2015 .SYNOPSIS... ISSUED AT 350 AM EDT MON AUG 10 2015 SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AS A LOW PRESSURE SYSTEM MOVES ACROSS THE REGION. A FEW OF THESE STORMS MAY PRODUCE HEAVY RAIN AND GUSTY WINDS ALONG AND EAST OF INTERSTATE 69 THIS AFTERNOON. HIGH PRESSURE AND DRY CONDITIONS RETURN OVERNIGHT AND PERSIST UNTIL THE END OF THE WEEK. ONE LAST MUGGY DAY TODAY WITH HIGHS AROUND 80 DEGREES BUT LESS HUMID AND SLIGHTLY COOLER CONDITIONS EXPECTED FOR THE REST OF THE WEEK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM EDT MON AUG 10 2015 ANOTHER "GRUNGY" DAY IN STORE FOR THE LOCAL FORECAST AREA AS BROAD MID/UPPER LEVEL HEIGHT FALLS INDUCE MODEST SURFACE CYCLOGENESIS OVER THE GREAT LAKES WITH A VERY MOIST/MARGINALLY UNSTABLE ENVIRONMENT IN PLACE. THIS SETUP WILL LIKELY LEAD TO SEVERAL ROUNDS OF SPORADIC SHOWERS AND A FEW EMBEDDED THUNDERSTORMS. ALREADY A FEW ISOLATED SHOWERS POPPING UP ACROSS THE REGION AND SHOULD SEE THIS ACTIVITY GRADUALLY EXPAND DURING THE DAY AS DIFFUSE SURFACE BOUNDARY CURRENTLY OVER IOWA PUSHES EASTWARD AND CAPITALIZES ON SOME DEGREE OF DIURNAL HEATING. LAST FEW RUNS OF HRRR (AND TO A LESSER EXTENT THE RAP) FINALLY SEEM TO HAVE A LITTLE BETTER HANDLE ON THE CURRENT PICTURE AND SUGGEST PRECIP WILL EXPAND IN OUR NORTHWEST COUNTIES DURING THE LATE MORNING (~14Z) AND PUSH SOUTHEASTWARD THROUGH THE DAY. THIS SEEMS REASONABLE BASED ON LATEST RADAR MOSAIC/SURFACE OBS AND BACKGROUND SYNOPTIC PATTERN. HAVE THEREFORE MASSAGED POP GRIDS A BIT TO REFLECT THIS EXPECTED EVOLUTION. MIDLEVEL LAPSE RATES DO GET A LITTLE BETTER WITH APPROACHING TROUGH AND AMPLE LOW LEVEL MOISTURE WILL SUPPORT AROUND 1500 J/KG OF SBCAPE IN OUR EASTERN HALF THIS AFTERNOON DESPITE ABUNDANT CLOUD COVER. THIS SHOULD BE ENOUGH FOR DECENT COVERAGE OF THUNDERSTORMS BUT POTENTIAL FOR STRONG UPDRAFTS AND SEVERE WEATHER APPEARS LOW. PASSING MIDLEVEL SPEED MAX DOES YIELD GOOD DEEP LAYER SHEAR NUMBERS BUT WIND PROFILES IN THE 0-3KM LAYER ARE FAIRLY LIGHT AND...GIVEN LESS THAN STELLAR INSTABILITY VALUES...SUGGEST A LOW SEVERE RISK. MAIN THREAT WOULD BE AN ISOLATED STRONG/SEVERE DOWNBURST WHERE ANY POCKETS OF ENHANCED CAPE MANAGE TO DEVELOP. POCKETS OF HEAVY RAIN ALSO POSSIBLE GIVEN PW VALUES AROUND 1.75 INCHES BUT RECENT DRY SPELL AND OVERALL LACKLUSTER SYNOPTIC FORCING SUGGEST THREAT FOR WIDESPREAD FLOODING IS LOW. PRECIP SHOULD EXIT THE CWA BY THIS EVENING WITH COOLER AND MUCH DRIER AIR FILTERING SOUTH. AFTER A MUGGY DAY TODAY WITH HIGHS AROUND 80F...EXPECT DEWPOINTS AND LOW TEMPS TO DROP BACK INTO THE LOWER 60S OVERNIGHT. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 350 AM EDT MON AUG 10 2015 HIGH PRESSURE OVER THE UPR MIDWEST TUE WILL MOVE SE TO INDIANA WED PROVIDING FAIR WEATHER ACROSS OUR AREA. NW FLOW ALOFT WILL ADVECT A COOL CANADIAN AIRMASS S-SE INTO OUR AREA RESULTING IN BLO NORMAL TEMPS THROUGH THIS TIMEFRAME. DRY WX SHOULD CONT THU AS THE HIGH MOVES SE OF THE AREA WITH WAA ON THE BACKSIDE OF THE HIGH RESULTING IN A LITTLE WARMER TEMPS. A CDFNT IS EXPECTED TO DROP SLOWLY S-SE ACROSS THE GRTLKS THU NGT- FRI NGT. UPR RIDGE AXIS OVER THE ROCKIES IS ALSO EXPECTED TO MOVE EAST IN THIS TIMEFRAME SO A GENERAL WKNG TREND OF THE FRONT IS EXPECTED... BUT MEDIUM RANGE MODELS IN DECENT AGREEMENT SUGGESTING AT LEAST SOME CONVECTION MAY FORM ALONG/AHEAD OF THE FRONT SO HAVE ADDED LOW POPS FOR LATE IN THE WORKWEEK. BY THE WEEKEND THE UPR RIDGE AXIS SHOULD MOVE OVER OUR AREA PROVIDING DRY WX WITH ABOVE NORMAL TEMPS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 136 AM EDT MON AUG 10 2015 AVIATION CONDITIONS STILL EXPECTED TO GRADUALLY DETERIORATE THROUGH THE MORNING AS BROAD TROUGH APPROACHES THE GREAT LAKES AND INTERACTS WITH VERY MOIST ENVIRONMENT. LIGHT WINDS AND HIGH SURFACE DEWPOINTS SUGGEST SOME PATCHY FOG AND LOW STRATUS POSSIBLE LATER THIS MORNING. LEFT FORECAST CATEGORIES LARGELY IN PLACE DUE TO LOWER CONFIDENCE...JUST ADJUSTED TIMING. ALSO ADDED A -SHRA MENTION GIVEN MOST HI-RES GUIDANCE SHOW PRECIP BLOSSOMING AROUND KSBN LATER THIS MORNING. CHANCE FOR A FEW THUNDERSTORMS AT KFWA THIS AFTERNOON GIVEN SOME MARGINAL DIURNAL DESTABILIZATION BUT EXACT TIMING AND COVERAGE REMAIN UNCERTAIN. CONDITIONS SHOULD IMPROVE BY THE END OF THE TAF PERIOD AS FRONT EXITS AND DRIER AIR FILTERS SOUTH. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...JT AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1137 PM MDT SUN AUG 9 2015 .SHORT TERM...(THIS AFTERNOON THROUGH MONDAY) ISSUED AT 132 PM MDT SUN AUG 9 2015 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOW RIDGE CONTINUING TO DOMINATE PATTERN ACROSS SOUTHERN P.LAINS WITH WESTERLY FLOW ACROSS THE NORTHERN PLAINS. H7 SHORTWAVE TROUGH HAS WEAKENED AND SHIFTED EAST...WITH ANOTHER H7 SHORTWAVE TROUGH OVER NORTHCENTRAL COLORADO. AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER OUR CWA...WITH A STATIONARY FRONT EXTENDING FROM NORTHEAST COLORADO ACROSS NORTHCENTRAL NEBRASKA. THIS AFTERNOON-TONIGHT...AS FIRST H7 TROUGH HAS WEAKENED AND SHIFTED EAST SUBSIDENCE HAS SPREAD INTO THE WESTERN PART OF THE FORECAST AREA WITH LOWER TD VALUES (UPPER 40S/LOWER 50S) ADVECTING INTO THE WESTERN PARTS OF THE FORECAST AREA. RESULT HAS BEEN CAPE VALUES DROPPING OFF SHARPLY AND SABLE AIR MOVING BACK OVER THE CWA. SHORT RANGE GUIDANCE CONTINUES TO KEEP HIGHER TD/CAPE VALUES IN OUR EASTERN CWA WITH ONLY 100-500 J/KG IN THE WEST THROUGH THE EVENING. CAPE VALUES AROUND 2000 J/KG ACROSS OUR EASTERN CWA COULD SUPPORT A FEW MARGINALLY SEVERE THUNDERSTORMS IF SOMETHING WAS TO DEVELOP ALONG WHAT IS LIKELY A DEVELOPING DRY LINE. NOT A LOT OF CONFIDENCE AND HI RES GUIDANCE HAS TRENDED AWAY FROM ADDITIONAL DEVELOPMENT IN OUR EAST. IT APPEARS THAT CHANCES ARE DECREASING FOR MOST OF THE CWA THIS AFTERNOON. THERE IS THE POSSIBILITY FOR A SHOWER OR THUNDERSTORM IN THE WESTERN CWA AS ANOTHER SHORTWAVE MOVES IN FROM THE WEST LATE THIS AFTERNOON THROUGH THIS EVENING...WITH BEST PRECIP SIGNAL IN THE SW. NOT A LOT OF CONFIDENCE AT THIS POINT IN COVERAGE...SO I DECIDED TO LIMIT POPS TO THE WEST THIS EVENING WITH A DOWNWARD TREND THROUGH 06Z. IT DOES APPEAR THAT HIGHER TD VALUES WILL BEGIN TO RECOVER OVERNIGHT FROM THE EAST/NORTHEAST WITH SURFACE HIGH PRESSURE/LOW LEVEL STABILITY SUPPORTING POSSIBLE FOG/STRATUS DEVELOPMENT. BASED ON SHORT RANGE GUIDANCE AND PERSISTENCE I KEPT HIGHER FOG COVERAGE (AREAS) LIMITED TO REPUBLICAN RIVER VALLEY IN SW NEBRASKA. MONDAY...GUIDANCE CONTINUES TO SHOW PRECIP SIGNAL LINGERING ACROSS THE SW PART OF OUR CWA. ANY SHORTWAVE TROUGHS/VORT MAXES ROTATING THROUGH PERIPHERY OF THE RIDGE APPEAR TO REMAIN SW OF OUR CWA WITH VERY LIMITED FORCING. INSTABILITY DOES BEGIN TO INCREASE SO IF ACTIVITY WAS TO DEVELOP TO THE WEST WE COULD SEE DEVELOPMENT TOWARDS THE SW PART OF OUR FORECAST AREA. I WASNT CONFIDENT ENOUGH TO INCREASE POPS DESPITE OVERLAPPING QPF FIELDS IN GUIDANCE...SO I LIMITED POPS TO 20/30 RANGE MONDAY AFTERNOON. HIGH TEMPS AS WITH THE LAST FEW DAYS WILL BE HIGHLY DEPENDENT ON MORNING STRATUS CLEARING WHICH IS CURRENTLY EXPECTED. RESULT SHOULD BE SEASONAL HIGHS IN THE UPPER 80S/AROUND 90. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 244 PM MDT SUN AUG 9 2015 FORECAST PROBLEM WILL BE CONTINUED THUNDERSTORM CHANCES. SATELLITE IS SHOWING AN AMPLIFIED AND MOSTLY PROGRESSIVE FLOW FROM THE PACIFIC INTO NORTH AMERICA. SOUTHERN UNITED STATES RIDGE REMAINS CENTERED OVER CENTRAL/EASTERN TEXAS. MODELS STARTED OUT FINE AT JET LEVEL. AT MID LEVELS...THE GFS/CANADIAN WERE INITIALLY DOING BETTER THAN THE REST OF THE OUT WITH THE NAM/SREF THE WORST OF THE REST OF THE BUNCH. THE SREF LOOKED LIKE IT WAS THE BEST AT THE SURFACE. IT LOOKED LIKE THE GFS...CANADIAN AND ECMWF WERE DOING THE BEST ON THE LOW LEVEL THERMAL FIELD AT THIS TIME. MONDAY NIGHT...LOW LEVEL UPSLOPE WINDS WILL BE IN PLACE THROUGH THE NIGHT AS SURFACE RIDGE NOSES DOWN INTO THE AREA. AS SHOWN THE LAST TWO DAYS...THE SHORTWAVE RIDGE AT 700 MB WILL SLOWLY MOVE TOWARD THE EAST THROUGH THE NIGHT AS A SHORTWAVE MOVES IN FROM THE WEST. MODELS HAVE SLOWED THINGS UP A LITTLE...AS HAS THE TREND BEEN THE LAST FEW DAYS AS WELL. THE GFS IS THE FURTHEST EAST WHICH IS NOT AN UCOMMON THING WHEN IT COMES TO BREAKING DOWN RIDGES TOO FAST. SO ONLY PROGRESSED THE POPS SLOWLY TO THE EAST THROUGH THE NIGHT. THE COMBINATION OF SLOW STORM MOVEMENT...PWS OF 1 TO 1.5 INCHES AND THE COMMON HEAVY RAIN SCENARIO OF A SHORTWAVE MOVING UP THE WEST SIDE OF A RIDGE COULD PRODUCE SOME LOCALIZED HEAVY RAINFALL. RAMPED THE AMOUNTS UP A LITTLE AND INCREASED THE INTENSITY OF THE RAINFALL AS WELL. THE BEST CHANCE FOR RAINFALL WILL BE IN THE SOUTHWEST THIRD TO HALF OF THE AREA. THIS PERIOD WILL NEED TO BE WASHED CLOSELY. TUESDAY/TUESDAY NIGHT...SLOWLY EVOLVING SITUATION THAT BEGINS MONDAY NIGHT...SLOWLY MOVING CONVECTIVELY INDUCED SYSTEM...CONTINUE THROUGH THIS ENTIRE PERIOD. MODELS ARE IN GOOD AGREEMENT ABOUT THIS. MORE THAN LIKELY SOME DEGREE OF CONVECTION WILL CONTINUE FROM THIS PREVIOUS THROUGH THIS ENTIRE PERIOD. AGAIN SAME HEAVY RAIN SCENARIO IS IN PLACE AS IN THE PREVIOUS PERIOD AND WILL HAVE TO BE WATCHED CLOSELY. ALSO THE SOUTHWEST THIRD TO HALF WILL HAVE THE BEST CHANCE OF RAINFALL...ESPECIALLY DURING THE DAY. THE AREA OF RAINFALL WILL SLOWLY MOVE TO THE SOUTH AND EAST DURING THE NIGHT. COMBINATION OF UPSLOPE SURFACE WINDS...LOTS OF CLOUD COVER AND ONGOING PRECIPITATION...WILL KEEP TEMPERATURES FROM WARMING UP TOO MUCH...ESPECIALLY IN THE SOUTHWEST HALF. SO LOWERED TEMPERATURES AROUND 5 DEGREES OR SO. THE COOLEST OUTPUT HAS TEMPERATURES COOLER THAN WHAT I HAVE THEM. WEDNESDAY...SLOW MOVING UPPER SYSTEM WILL KEEP RAINFALL AROUND THROUGH THE MORNING HOURS IN THE SOUTHEAST HALF. IF THERE IS ANY MORE SLOWLY...THE POPS WILL NEED TO BE RAISED. TEMPERATURES WILL BE A LITTLE WARMER BUT HOW MUCH WILL DEPEND ON HOW FAST THE SYSTEM AND ASSOCIATED CLOUDS/RAINFALL MOVE OUT OF THE AREA. AGAIN IF ANY MORE SLOWING TEMPERATURES WILL NEED TO BE LOWERED. WEDNESDAY NIGHT THROUGH SUNDAY...NOT TOO MUCH HAS CHANGED FROM WHAT THE MODELS HAVE BEEN DOING/SHOWING FROM THE LAST FEW DAYS. MODELS STILL DIFFER ON THE AMPLITUDED AND POSITION OF WHAT IS NOW THE SOUTHERN RIDGE THAT TRANSITIONS TO A MORE CENTERED WESTERN RIDGE. IN GENERAL UPPER RIDGE STAYS CENTERED NEAR THE FOUR CORNERS REGION. SINCE MUCH DOES CHANGE ALOFT...THE SURFACE ALSO DOES NOT CHANGE TOO MUCH. A SURFACE TROUGH OR LINGERING FRONTAL BOUNDARY STAYS NEAR OR OVER THE WESTERN PORTION OF THE AREA. FORECAST WILL HINGE ON SMALL IMPORTANT DETAILS THAT WILL BE HARD TO PIN DOWN AT THIS TIME SCALE. POSITION OF THE RIDGE SHOULD ALLOW SUBTROPICAL MOISTURE/WEAK SHORTWAVE TROUGHS TO ROTATE AROUND THE RIDGE INTO THE AREA. ALSO THE SURFACE BOUNDARY SHOULD HELP SET THUNDERSTORMS OFF. THERE WILL NOT BE HIGH PRECIPITATION CHANCES BUT HARD TO SAY THERE WILL NOT BE ANYTHING AT ALL. PER THE OVERNIGHT DISCUSSION/REASONING...THE WESTERN PORTION OF THE AREA WILL PROBABLY SEE THE BEST CHANCE DUE TO THE PROXIMITY OF THE SURFACE BOUNDARY. THE NEW CRH_INIT IS IN GOOD AGREEMENT WITH THE ABOVE MENTIONED SCENARIO/REASONING...SO ONCE AGAIN MADE NO CHANGES TO IT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1131 PM MDT SUN AUG 9 2015 VFR CONDITIONS ARE EXPECTED AT KGLD FOR THE NEXT 24 HOURS. LATER TONIGHT, BOUNDARY LAYER RH INCREASES TO 90 PERCENT OR MORE IN AN AREA INCLUDING KMCK. CONDITIONS THERE MAY GET AS LOW AS IFR. VFR CONDITIONS WILL RETURN TO KMCK BY MID MORNING. LATER MONDAY AFTERNOON AND EVENING THERE IS A SLIGHT CHANCE OF THUNDERSTORMS NEAR KGLD SO WILL INCLUDE VCTS. KMCK SHOULD NOT HAVE THUNDERSTORMS UNTIL AFTER 06Z TUESDAY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...FS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1159 PM CDT SUN AUG 9 2015 ...UPDATE TO SHORT TERM CONVECTIVE FORECAST AND AVIATION FORECAST DISCUSSION... .UPDATE... ISSUED AT 1152 PM CDT SUN AUG 9 2015 WHILE FORCING MECHANISMS REMAIN WEAK, THE ATMOSPHERE REMAINS QUITE UNSTABLE WITH 2000-4000 J/KG OF MUCAPE ROOTED 2-3K FEET OFF THE SURFACE. EFFECTIVE SHEAR IS SUFFICIENT TO SUSTAIN SUPERCELL STRUCTURES MAINLY OVER NORTHERN PARTS OF THE AREA AND THE STORM OVER REPUBLIC COUNTY HAS SHOWN SIGNS OF ORGANIZATION ALTHOUGH IT HAS SO FAR REMAINED BELOW SEVERE LIMITS AND STRUGGLED TO REMAIN ORGANIZED FOR A PROLONGED PERIOD. AN ADDITIONAL AREA OF CONVERGENCE AND INCREASING CLOUD COVER IN THE 3500 FOOT AGL RANGE INDICATE THAT ADDITIONAL SCATTERED STORMS MAY DEVELOP GENERALLY ALONG THE I-70 CORRIDOR IN THE NEXT COUPLE OF HOURS AND THEN PERHAPS INTO EAST CENTRAL KANSAS. BASICALLY, THERE ARE SEVERAL AREAS OF WEAK FORCING AND WHETHER OR NOT ANY OF THESE AREAS CAN INITIATE CONVECTION ARE THE PRIMARY QUESTION. IF STORMS DEVELOP, A FEW STRONG TO SEVERE STORMS ARE POSSIBLE WITH WIND REMAINING THE PRIMARY HAZARD ALONG WITH POCKETS OF HEAVY RAIN AND A SMALL CHANCE FOR MARGINALLY SEVERE HAIL. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 313 PM CDT SUN AUG 9 2015 CURRENT SURFACE ANALYSIS SHOWS THE MAIN SYNOPTIC BOUNDARY EXTENDING SOUTHWARD FROM KANSAS CITY TO WICHITA, WHICH IS FORECAST TO SAG SOUTHWARD THROUGH THE AFTERNOON AND EVENING HOURS. ALTHOUGH THE MORE EVIDENT THERMAL GRADIENT HAS PUSHED INTO SOUTHEAST KS AND HAS BEEN RESPONSIBLE FOR SCATTERED SHOWERS AND ISOLATED THUNDER THIS MORNING. THIS HAS KEPT THE CLOUD COVER AROUND MUCH LONGER THAN FORECASTED, BUT AN AREA OF CLEAR SKIES IS WORKING EASTWARD ACROSS NORTHEAST KS, WHICH MAY ALLOW TEMPERATURES TO WARM INTO THE LOWER TO MIDDLE 90S. HIGH MOISTURE POOLING IN THE BOUNDARY LAYER HAS KEPT DEW POINTS IN THE MID TO UPPER 70S. EXPECT THAT HEAT INDICES WILL BE IN THE LOWER 100S THROUGH EARLY EVENING FOR LOCATIONS ALONG AND SOUTH OF I-70. THERE WILL BE A FEW THINGS OF CONCERN LATER THIS EVENING AND OVERNIGHT. THE MODELS SHOW A SHORTWAVE TROUGH ON THE NORTHERN PERIPHERY OF THE UPPER HIGH CENTERED OVER THE SOUTHERN PLAINS WILL TRACK ACROSS SOUTHERN KS TONIGHT. THIS MAY SUPPORT THE DEVELOPMENT OF AN MCS OR MULTICELL CLUSTER IN WESTERN OR CENTRAL KS THIS EVENING NORTH OF THE SURFACE BOUNDARY. SURFACE BASED CONVECTION HAS ALREADY BEGAN IN NORTHWEST KS. AS THAT BOUNDARY DRIFTS SOUTHWARD THE TRACK OF THE MCS MAY ALSO DO THE SAME AS DEPICTED BY THE NAM. THE PAST FEW RUNS OF THE HRRR HAVE BEEN CLIPPING THE SOUTHERN FORECAST AREA WITH THIS MCS. INSTABILITY HAS BEEN SOMEWHAT LIMITED TODAY ACROSS SOUTHERN KS AS OPPOSED TO NORTHERN KS, WHICH HAS SET UP A DECENT GRADIENT. THEREFORE IT IS UNCERTAIN HOW SEVERE THESE STORMS WILL BE THIS EVENING, BUT THE TRACK MAY BE MORE FOCUSED ALONG THIS INSTABILITY GRADIENT INSTEAD. AS FOR NOW THE BEST CHANCES FOR PRECIP WILL BE SOUTH OF I-70 LATE THIS EVENING AND EARLY MORNING WITH THE SLIGHT CHANCE FOR A STRONG STORM. WITH PLENTY OF MOISTURE AROUND AND LIGHT LOW LEVEL WINDS ASSOCIATED WITH THE BOUNDARY THERE IS A CHANCE FOR HAZE AND OR FOG EARLY TOMORROW MORNING. THERE ARE SOME INDICATIONS THAT THE SKIES COULD CLEAR LATE TONIGHT AND ALLOW FOR BOUNDARY LAYER COOLING. A FEW OF THE MODELS ARE HINTING AT A NORTHERN SHORTWAVE THAT WILL TRACK OVER SD AND NE OVERNIGHT. THIS MAY ALSO SUPPORT A SOUTHEASTWARD MOVING MCS THAT COULD REACH NORTHERN KS AROUND SUNRISE. IN FACT, THE INSTABILITY IS ALREADY DECENT IN THAT AREA, WHICH WOULD SUPPORT THIS SCENARIO BETTER. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 313 PM CDT SUN AUG 9 2015 THERE IS NOT MUCH CHANGE IN THE FORECAST FOR MONDAY NIGHT THROUGH SUNDAY AS MODELS CONTINUE TO SHOW AN UPPER LEVEL RIDGE AMPLIFYING TO THE WEST AND SOUTHWEST CAUSING NORTHWEST FLOW TO SET UP OVER THE FORECAST AREA. ABOUT THE ONLY THING OF CONCERN IS THE POSSIBILITY FOR SOME ELEVATED PRECIP ACROSS NORTH CENTRAL KS LATE TUESDAY NIGHT AND WEDNESDAY MORNING. THERE ARE INDICATIONS THAT CONVECTION IN THE MOUNTAINS COULD GENERATE A VORT MAX AND THEN DRIFT EAST AND SOUTH THROUGH CENTRAL KS. FOR NOW MOST GUIDANCE KEEPS ANY PRECIP JUST TO THE WEST OF THE FORECAST AREA. THIS SEEMS TO MAKE SINCE AS MODELS BRING THE CENTER OF THE 850 MB RIDGE OVER THE FORECAST AREA BY 12Z WED WITH NO REAL RETURN FLOW AND THE DEEPER MOISTURE AXIS REMAINING OVER WESTERN KS. SO THE FORECAST REMAINS DRY THROUGH NEXT WEEKEND WITH NO OBVIOUS SIGNS OF FORCING IMPACTING THE FORECAST AREA AFTER WEDNESDAY. TEMPS ARE EXPECTED TO BE COOLER THAN NORMAL FOR TUESDAY THROUGH THURSDAY. MODELS ARE IN AGREEMENT THAT A MODIFIED HIGH PRESSURE SYSTEM WILL BUILD INTO THE AREA WITH SOME WEAK COLD AIR ADVECTION AND DRYER AIR. BECAUSE OF THIS LOWS SHOULD BE IN THE LOWER AND MID 60S WITH HIGHS IN THE 80S. BY FRIDAY AND INTO THE WEEKEND, THE UPPER RIDGE IS EXPECTED TO PROPAGATE EAST INTO THE PLAINS AS AN UPPER TROUGH OVER THE PACIFIC NORTHWEST COAST MOVES INLAND. THIS SHOULD SHIFT THE THERMAL RIDGE OUT INTO THE PLAINS WITH HIGHS WARMING BACK INTO THE LOWER AND MID 90S FOR THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1152 PM CDT SUN AUG 9 2015 LOWER THAN NORMAL CONFIDENCE CONTINUES IN THE TAF. SCATTERED THUNDERSTORMS MAY DEVELOP NEAR/OVER TAF SITES AT JUST ABOUT ANY TIME THROUGH 13 OR 14Z. OTHERWISE DO EXPECT MVFR CIGS TO DEVELOP IN THE NEXT FEW HOURS, PROBABLY BY 08Z...AND WITH SUCH AMPLE LOW LEVEL MOISTURE MAY SEE SOME VIS RESTRICTIONS ESPECIALLY AFTER 09Z. CIGS, LIKELY IN THE MVFR RANGE, EXPECTED TO CONTINUE THROUGH AROUND NOON BEFORE SCATTERING OUT. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARJENBRUCH SHORT TERM...SANDERS LONG TERM...WOLTERS AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS JACKSON KY
150 AM EDT MON AUG 10 2015 .UPDATE... ISSUED AT 150 AM EDT MON AUG 10 2015 UPPER WAVE RIDING THROUGH THE FLOW HAS FIRED OFF SOME SHOWERS AHEAD OF MAIN SURFACE LOW PRESSURE/COLD FRONT STILL DEVELOPING ACROSS THE MIDWEST THIS EARLY MORNING HOUR. ALL THE PRECIP HAS REMAINED LIGHT IN NATURE AT THIS POINT BASED OF THE LATEST WSR-88D SWEEPS. DID UPDATE GRIDS TO ADD AT LEAST SOME ISOLATED POPS ACROSS MUCH OF THE REGION OVERNIGHT...OTHERWISE MINOR ADJUSTMENTS MADE TO THE TEMPS/DEWS/WINDS TOWARD LATEST OBS/TRENDS. UPDATE ISSUED AT 1045 PM EDT SUN AUG 9 2015 A SHORTWAVE MOVING THROUGH THE OH VALLEY REGION IS BRINGING SOME SHOWERS TO SOUTHERN OH AND NORTHERN KY. KCVG ONLY TRACED AS THESE PASSED...SO THESE LIKELY DO NOT AMOUNT TO MUCH MORE THAN SPRINKLES. OTHERWISE...MODELS INDICATE ADDITIONAL CONVECTION UPSTREAM WILL MOVE EAST AND OR DEVELOP AND MOVE EAST TO EAST SOUTHEAST AS IT WORKS AROUND THE MID LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS. DUE TO UNCERTAINTY IN TIMING AND MODEL DIFFERENCES IN EVOLUTION OF CONVECTION OVERNIGHT AND INTO THE DAY ON MONDAY...NO CHANGES WERE MADE TO POPS TOWARD DAWN. THE ONLY CHANGES TO POPS WERE IN THE SHORT TERM TO ACCOUNT FOR THE SHOWERS MOVING TOWARD NE KY. OTHERWISE...HOURLY GRIDS WERE FRESHENED UP BASED ON RECENT OBSERVATIONS AND SATELLITE TRENDS. UPDATE ISSUED AT 820 PM EDT SUN AUG 9 2015 A MID LEVEL RIDGE OF HIGH PRESSURE WAS CENTERED OVER THE SOUTHERN PLAINS WITH A SERIES OF SHORTWAVES MOVING THROUGH OR NEARING THE LOWER OH VALLEY AS THEY MOVE AROUND THIS RIDGE. AT THE SAME TIME... A SERIES OF SHORTWAVE TROUGH WILL APPROACH OR MOVE THROUGH THE GREAT LAKES. ALL OF THIS WILL BEGIN TO CARVE OUT AN EASTERN US TROUGH WHILE THE RIDGE BUILDS NORTH INTO THE NORTHERN ROCKIES. AT THE SFC..AN AREA OF LOW PRESSURE WILL TRACK INTO THE LOWER GREAT LAKES WITH THE WARM FRONT LIFTING INTO THE REGION WHILE A COLD FRONT MOVES INTO THE LOWER OH VALLEY. OVERALL...MOISTURE AND FORCING WILL INCREASE OVERNIGHT ACROSS THE OH VALLEY REGION...BUT CONFIDENCE REMAINS LOW IN THE EVOLUTION OF CONVECTION OVERNIGHT. WITH RECENT MODEL GUIDANCE STILL SUPPORTING CHANCES FOR CONVECTION LATE TONIGHT AND SOME DISAGREEMENT AS TO WHERE CHANCES MAY BE BEST...NO CHANGES WERE MADE TO POPS AND WEATHER ATTM. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 345 PM EDT SUN AUG 9 2015 18Z SFC ANALYSIS SHOWS HIGH PRESSURE STILL IN CONTROL OF THE WEATHER ACROSS EAST KENTUCKY. HIGH CLOUDS ARE MOVING IN FROM THE NORTHWEST AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM WHILE SCATTERED CU IS DISSIPATING OVER THE AREA. TEMPERATURES ARE TOPPING OUT IN THE MIDDLE TO UPPER 80S THROUGH EAST KENTUCKY WHILE DEWPOINTS VARY FROM THE MID 60S NORTH TO THE LOWER 70S IN THE SOUTH WITH LIGHT AND VARIABLE WINDS. THE MODELS ARE IN GOOD AGREEMENT WITH THE PATTERN ALOFT OVER THE REGION. THEY ALL DEPICT KENTUCKY ON THE NORTHEAST FRINGE OF A STRONG RIDGE CENTERED OVER CENTRAL TEXAS. THIS PLACES THE AREA IN NORTHWEST FLOW WITH A COUPLE OF MINOR SHORTWAVES GLIDING PAST THE CWA INTO MONDAY MORNING. THE PATTERN WILL FURTHER AMPLIFY THROUGH THE OHIO VALLEY AND APPALACHIANS AS A TROUGH FROM CENTRAL CANADA WILL DIVE INTO THE GREAT LAKES LATER MONDAY...SWEEPING INTO THE OHIO VALLEY BY 12Z TUESDAY. SIGNIFICANT HEIGHT FALLS WILL SPREAD OVER EASTERN KENTUCKY AS A RESPONSE ALONG WITH ADDITIONAL ENERGY CLUSTERS. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED THE HIGHER RESOLUTION HRRR AND NAM12 MOST CLOSELY INITIALLY FOLLOWING WITH WITH IDEAS FROM THE GFS AND ECMWF LATER ON IN THE SHORT TERM. SENSIBLE WEATHER WILL FEATURE A QUIET EVENING UNDER HIGH CLOUDS...THIN ENOUGH TO YIELD A SMALL RIDGE TO VALLEY TEMPERATURE SPLIT. THE CLOUDS WILL THICKEN UP DURING THE EARLY MORNING HOURS WITH A SEMI-ORGANIZED AREA OF SHOWERS AND THUNDERSTORMS POTENTIALLY MOVING INTO THE AREA DURING THE PRE-DAWN HOURS FROM NORTHWEST TO SOUTHEAST. THIS MAY STABILIZE THE ENVIRONMENT FOR A TIME BEFORE INSTABILITY BUILDS ENOUGH FOR ANOTHER ROUND OF ACTIVITY LATER IN THE DAY MONDAY. FROM EITHER OF THESE ROUNDS OF CONVECTION A STORM OR TWO COULD GET STRONG ENOUGH TO MAKE DAMAGING WIND GUSTS A POTENTIAL THREAT - WILL ADDRESS THIS IN THE FORTHCOMING HWO. THIS SYSTEM/S COLD FRONT WILL PASS THROUGH LATER MONDAY NIGHT WITH A LINGER SHOT AT SHOWERS OR STORMS AS IT EXITS EARLY TUESDAY MORNING. DUE TO THE CLOUD COVER TONIGHT AND MONDAY NIGHT HAVE KEPT FOG TO A MINIMUM IN THE GRIDS...BUT IT COULD BE MORE SUBSTANTIAL TUESDAY MORNING SHOULD THE CLOUDS AND PCPN MANAGE TO CLEAR OUT EARLIER MONDAY NIGHT. AGAIN USED THE SHORTBLEND GUIDANCE AS A STARTING POINT THROUGH THE FIRST PART OF THE FORECAST FOR THE T/TD/WIND GRIDS WITH A SWITCH TO THE SUPERBLEND FOR THE REMAINDER. DID MAKE SOME MINOR CHANGES TO LOWS TONIGHT BASED ON THE TERRAIN WITH A SMALL RIDGE TO VALLEY SPLIT EXPECTED INTO THE EARLY MORNING HOURS. AS FOR POPS...ENDED UP CLOSEST TO THE MET NUMBERS THROUGH THE PERIOD. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 313 PM EDT SUN AUG 9 2015 THE MAJORITY OF THE EXTENDED LOOKS TO BE DRY AND PLEASANT WITH SHOWERS AND STORMS AFFECTING EASTERN KENTUCKY DURING THE DAY ON TUESDAY...AND BELOW NORMAL TEMPERATURES TUESDAY THROUGH FRIDAY. MOIST UPSLOPE FLOW BEHIND A DEPARTING WEATHER SYSTEM WILL ALLOW PRECIPITATION TO LINGER ACROSS THE AREA THROUGH LATE TUESDAY AFTERNOON. THE PRECIPITATION WILL BE USHERED OUT OF EASTERN KENTUCKY AS A STRONG RIDGE OF HIGH PRESSURE BEGINS BUILDING INTO THE AREA FROM THE WEST. THIS FEATURE WILL BRING DRY CONDITIONS AND COOLER THAN NORMAL TEMPERATURES TO EAST KENTUCKY FOR THE REST OF THE WEEK...AS A COOL AND DRY AIR MASS MOVES FROM THE NORTHERN ROCKY MOUNTAIN REGION AND INTO THE OHIO AND TENNESSEE VALLEY REGIONS. HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY ARE EXPECTED TO MAX OUT IN THE UPPER 70S FOR MOST LOCATIONS...WITH LOWER 80S FOR HIGHS ON TAP FOR TUESDAY AND FRIDAY. OVERNIGHT LOWS MAY FALL AS LOW AS THE MID TO UPPER 50S WEDNESDAY NIGHT AND THURSDAY NIGHT AS CLEAR SKIES AND NEAR CALM WINDS REMAIN IN PLACE. MINIMUM READINGS ARE EXPECTED TO BOTTOM OUT IN THE 60S THE OTHER NIGHTS OF THE UPCOMING WORK WEEK...WITH LOW TO MID 60S EXPECTED FOR FRIDAY NIGHT AND SATURDAY NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 115 AM EDT MON AUG 10 2015 VFR CONDITIONS PREVAIL ACROSS EASTERN KY THIS OVERNIGHT HOUR. THERE ARE A FEW SHOWERS AND SPRINKLES THAT HAVE DEVELOPED ACROSS PORTIONS OF THE REGION...SO DID GO WITH SOME VCSH AT MOST SITES. HOWEVER SITES SHOULD REMAIN VFR THROUGH MUCH OF THE BEGINNING OF THE PERIOD. UPSTREAM MCS RELATED CONVECTION IN WESTERN KY HAS BEEN ON A WEAKENING TREND AND WILL PROBABLY MISS THE REGION IN GENERAL. OTHERWISE THINK THE BETTER CONVECTION WILL DEVELOP LATER MORNING INTO THE AFTERNOON HOURS. THEREFORE STAYED CLOSE TO THE PREVIOUS FORECAST WITH TEMPO GROUP TO EXPRESS DROPS TO MVFR/IFR AT TIMES TOMORROW AFTERNOON AND EARLY EVENING. WINDS WILL BE GENERALLY LIGHT THROUGH THE PERIOD WITH HIGHER GUSTS POSSIBLE IN STRONGER STORMS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DJ SHORT TERM...GREIF LONG TERM...AR AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
115 AM EDT MON AUG 10 2015 .UPDATE... ISSUED AT 1045 PM EDT SUN AUG 9 2015 A SHORTWAVE MOVING THROUGH THE OH VALLEY REGION IS BRINGING SOME SHOWERS TO SOUTHERN OH AND NORTHERN KY. KCVG ONLY TRACED AS THESE PASSED...SO THESE LIKELY DO NOT AMOUNT TO MUCH MORE THAN SPRINKLES. OTHERWISE...MODELS INDICATE ADDITIONAL CONVECTION UPSTREAM WILL MOVE EAST AND OR DEVELOP AND MOVE EAST TO EAST SOUTHEAST AS IT WORKS AROUND THE MID LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS. DUE TO UNCERTAINTY IN TIMING AND MODEL DIFFERENCES IN EVOLUTION OF CONVECTION OVERNIGHT AND INTO THE DAY ON MONDAY...NO CHANGES WERE MADE TO POPS TOWARD DAWN. THE ONLY CHANGES TO POPS WERE IN THE SHORT TERM TO ACCOUNT FOR THE SHOWERS MOVING TOWARD NE KY. OTHERWISE...HOURLY GRIDS WERE FRESHENED UP BASED ON RECENT OBSERVATIONS AND SATELLITE TRENDS. UPDATE ISSUED AT 820 PM EDT SUN AUG 9 2015 A MID LEVEL RIDGE OF HIGH PRESSURE WAS CENTERED OVER THE SOUTHERN PLAINS WITH A SERIES OF SHORTWAVES MOVING THROUGH OR NEARING THE LOWER OH VALLEY AS THEY MOVE AROUND THIS RIDGE. AT THE SAME TIME... A SERIES OF SHORTWAVE TROUGH WILL APPROACH OR MOVE THROUGH THE GREAT LAKES. ALL OF THIS WILL BEGIN TO CARVE OUT AN EASTERN US TROUGH WHILE THE RIDGE BUILDS NORTH INTO THE NORTHERN ROCKIES. AT THE SFC..AN AREA OF LOW PRESSURE WILL TRACK INTO THE LOWER GREAT LAKES WITH THE WARM FRONT LIFTING INTO THE REGION WHILE A COLD FRONT MOVES INTO THE LOWER OH VALLEY. OVERALL...MOISTURE AND FORCING WILL INCREASE OVERNIGHT ACROSS THE OH VALLEY REGION...BUT CONFIDENCE REMAINS LOW IN THE EVOLUTION OF CONVECTION OVERNIGHT. WITH RECENT MODEL GUIDANCE STILL SUPPORTING CHANCES FOR CONVECTION LATE TONIGHT AND SOME DISAGREEMENT AS TO WHERE CHANCES MAY BE BEST...NO CHANGES WERE MADE TO POPS AND WEATHER ATTM. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 345 PM EDT SUN AUG 9 2015 18Z SFC ANALYSIS SHOWS HIGH PRESSURE STILL IN CONTROL OF THE WEATHER ACROSS EAST KENTUCKY. HIGH CLOUDS ARE MOVING IN FROM THE NORTHWEST AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM WHILE SCATTERED CU IS DISSIPATING OVER THE AREA. TEMPERATURES ARE TOPPING OUT IN THE MIDDLE TO UPPER 80S THROUGH EAST KENTUCKY WHILE DEWPOINTS VARY FROM THE MID 60S NORTH TO THE LOWER 70S IN THE SOUTH WITH LIGHT AND VARIABLE WINDS. THE MODELS ARE IN GOOD AGREEMENT WITH THE PATTERN ALOFT OVER THE REGION. THEY ALL DEPICT KENTUCKY ON THE NORTHEAST FRINGE OF A STRONG RIDGE CENTERED OVER CENTRAL TEXAS. THIS PLACES THE AREA IN NORTHWEST FLOW WITH A COUPLE OF MINOR SHORTWAVES GLIDING PAST THE CWA INTO MONDAY MORNING. THE PATTERN WILL FURTHER AMPLIFY THROUGH THE OHIO VALLEY AND APPALACHIANS AS A TROUGH FROM CENTRAL CANADA WILL DIVE INTO THE GREAT LAKES LATER MONDAY...SWEEPING INTO THE OHIO VALLEY BY 12Z TUESDAY. SIGNIFICANT HEIGHT FALLS WILL SPREAD OVER EASTERN KENTUCKY AS A RESPONSE ALONG WITH ADDITIONAL ENERGY CLUSTERS. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED THE HIGHER RESOLUTION HRRR AND NAM12 MOST CLOSELY INITIALLY FOLLOWING WITH WITH IDEAS FROM THE GFS AND ECMWF LATER ON IN THE SHORT TERM. SENSIBLE WEATHER WILL FEATURE A QUIET EVENING UNDER HIGH CLOUDS...THIN ENOUGH TO YIELD A SMALL RIDGE TO VALLEY TEMPERATURE SPLIT. THE CLOUDS WILL THICKEN UP DURING THE EARLY MORNING HOURS WITH A SEMI-ORGANIZED AREA OF SHOWERS AND THUNDERSTORMS POTENTIALLY MOVING INTO THE AREA DURING THE PRE-DAWN HOURS FROM NORTHWEST TO SOUTHEAST. THIS MAY STABILIZE THE ENVIRONMENT FOR A TIME BEFORE INSTABILITY BUILDS ENOUGH FOR ANOTHER ROUND OF ACTIVITY LATER IN THE DAY MONDAY. FROM EITHER OF THESE ROUNDS OF CONVECTION A STORM OR TWO COULD GET STRONG ENOUGH TO MAKE DAMAGING WIND GUSTS A POTENTIAL THREAT - WILL ADDRESS THIS IN THE FORTHCOMING HWO. THIS SYSTEM/S COLD FRONT WILL PASS THROUGH LATER MONDAY NIGHT WITH A LINGER SHOT AT SHOWERS OR STORMS AS IT EXITS EARLY TUESDAY MORNING. DUE TO THE CLOUD COVER TONIGHT AND MONDAY NIGHT HAVE KEPT FOG TO A MINIMUM IN THE GRIDS...BUT IT COULD BE MORE SUBSTANTIAL TUESDAY MORNING SHOULD THE CLOUDS AND PCPN MANAGE TO CLEAR OUT EARLIER MONDAY NIGHT. AGAIN USED THE SHORTBLEND GUIDANCE AS A STARTING POINT THROUGH THE FIRST PART OF THE FORECAST FOR THE T/TD/WIND GRIDS WITH A SWITCH TO THE SUPERBLEND FOR THE REMAINDER. DID MAKE SOME MINOR CHANGES TO LOWS TONIGHT BASED ON THE TERRAIN WITH A SMALL RIDGE TO VALLEY SPLIT EXPECTED INTO THE EARLY MORNING HOURS. AS FOR POPS...ENDED UP CLOSEST TO THE MET NUMBERS THROUGH THE PERIOD. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 313 PM EDT SUN AUG 9 2015 THE MAJORITY OF THE EXTENDED LOOKS TO BE DRY AND PLEASANT WITH SHOWERS AND STORMS AFFECTING EASTERN KENTUCKY DURING THE DAY ON TUESDAY...AND BELOW NORMAL TEMPERATURES TUESDAY THROUGH FRIDAY. MOIST UPSLOPE FLOW BEHIND A DEPARTING WEATHER SYSTEM WILL ALLOW PRECIPITATION TO LINGER ACROSS THE AREA THROUGH LATE TUESDAY AFTERNOON. THE PRECIPITATION WILL BE USHERED OUT OF EASTERN KENTUCKY AS A STRONG RIDGE OF HIGH PRESSURE BEGINS BUILDING INTO THE AREA FROM THE WEST. THIS FEATURE WILL BRING DRY CONDITIONS AND COOLER THAN NORMAL TEMPERATURES TO EAST KENTUCKY FOR THE REST OF THE WEEK...AS A COOL AND DRY AIR MASS MOVES FROM THE NORTHERN ROCKY MOUNTAIN REGION AND INTO THE OHIO AND TENNESSEE VALLEY REGIONS. HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY ARE EXPECTED TO MAX OUT IN THE UPPER 70S FOR MOST LOCATIONS...WITH LOWER 80S FOR HIGHS ON TAP FOR TUESDAY AND FRIDAY. OVERNIGHT LOWS MAY FALL AS LOW AS THE MID TO UPPER 50S WEDNESDAY NIGHT AND THURSDAY NIGHT AS CLEAR SKIES AND NEAR CALM WINDS REMAIN IN PLACE. MINIMUM READINGS ARE EXPECTED TO BOTTOM OUT IN THE 60S THE OTHER NIGHTS OF THE UPCOMING WORK WEEK...WITH LOW TO MID 60S EXPECTED FOR FRIDAY NIGHT AND SATURDAY NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 115 AM EDT MON AUG 10 2015 VFR CONDITIONS PREVAIL ACROSS EASTERN KY THIS OVERNIGHT HOUR. THERE ARE A FEW SHOWERS AND SPRINKLES THAT HAVE DEVELOPED ACROSS PORTIONS OF THE REGION...SO DID GO WITH SOME VCSH AT MOST SITES. HOWEVER SITES SHOULD REMAIN VFR THROUGH MUCH OF THE BEGINNING OF THE PERIOD. UPSTREAM MCS RELATED CONVECTION IN WESTERN KY HAS BEEN ON A WEAKENING TREND AND WILL PROBABLY MISS THE REGION IN GENERAL. OTHERWISE THINK THE BETTER CONVECTION WILL DEVELOP LATER MORNING INTO THE AFTERNOON HOURS. THEREFORE STAYED CLOSE TO THE PREVIOUS FORECAST WITH TEMPO GROUP TO EXPRESS DROPS TO MVFR/IFR AT TIMES TOMORROW AFTERNOON AND EARLY EVENING. WINDS WILL BE GENERALLY LIGHT THROUGH THE PERIOD WITH HIGHER GUSTS POSSIBLE IN STRONGER STORMS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...AR AVIATION...DJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT MON AUG 10 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 509 AM EDT MON AUG 10 2015 WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A RIDGE OVER THE ROCKIES WITH DOWNSTREAM TROF BEGINNING TO DEEPEN FROM HUDSON BAY S INTO THE GREAT LAKES. IN THE DEVELOPING NW FLOW INTO THE GREAT LAKES...THERE IS ONE SHORTWAVE OF NOTE UPSTREAM E OF LAKE WINNIPEG ALONG THE ONTARIO/MANITOBA BORDER. CLOSER TO HOME...SCT SHRA CONTINUE EARLY THIS MORNING OVER ROUGHLY THE E HALF UPPER MI...AHEAD OF COLD FRONT. WILL CONTINUE TO CARRY SCT SHRA OVER THE ERN FCST AREA THIS MORNING AHEAD OF SLOW MOVING COLD FRONT. MIGHT BE A FEW RUMBLES OF THUNDER. WHERE CLOUDS SCATTER OUT...EXPECT SOME FOG UNTIL MID MORNING... ESPECIALLY IN THOSE AREAS WHERE RAINFALL HAS OCCURRED OVER THE LAST 12HRS. THIS AFTN...UNDER NNW FLOW...LAKE BREEZE COMPONENTS TO WIND WILL LEAD TO AN AREA OF CONVERGENCE IN SCNTRL UPPER MI. WITH POTENTIAL OF 50-200J/KG OF MLCAPE PER GFS/RAP/HRRR...ISOLD SHRA/TSTM MAY DEVELOP (NAM LOOKS WAY TOO HIGH WITH MLCAPES OVER 1000J/KG). WITH MOST OF THE HIGH RES MODEL GUIDANCE SHOWING SOME CONVECTION IN THAT AREA...WILL INCLUDE SCHC TO LOW CHC POPS IN SCNTRL UPPER MI THIS AFTN. AHEAD OF THE LAKE BREEZE OFF LAKE SUPERIOR...MAY SEE A FEW SHRA/TSRA E TOWARD KISQ/KERY AS WELL. AS SHORTWAVE CURRENTLY E OF LAKE WINNIPEG DROPS SE...REACHING WRN LAKE SUPERIOR THIS EVENING...THERE SHOULD BE QUITE A BIT OF SHRA AND SOME TSTMS DEVELOPING NW OF LAKE SUPERIOR THIS AFTN. THIS CONVECTION WILL SPREAD OUT OVER NW LAKE SUPERIOR IN THE AFTN. NOT SURE HOW FAR THIS ACTIVITY WILL SPREAD BEFORE DISSIPATING OVER THE COOLER MARINE LAYER. HOWEVER...WITH WATER NOT AS COLD AS EARLIER IN THE SUMMER AND WITH SUPPORT FROM DECENT LOOKING SHORTWAVE...SOME OF THIS ACTIVITY CERTAINLY HAS THE POTENTIAL TO SURVIVE IN A WEAKENED STATE INTO NW UPPER MI LATE THIS AFTN/EARLY EVENING. ANY -SHRA THAT SURVIVE THE TRIP ACROSS THE LAKE INTO NW UPPER MI WILL DISSIPATE THIS EVENING AS SHORTWAVE QUICKLY MOVES E OF THE AREA. THIS WILL LEAD TO A QUIET OVERNIGHT. SINCE GFS AND ESPECIALLY NAM SUGGEST AN INCREASE IN LOW CLOUDS OCCURRING LATE IN THE NIGHT INTO TUE MORNING...CLOUD COVERAGE WAS TRENDED UP OVERNIGHT... ESPECIALLY ACROSS THE N WHERE UPSLOPE WIND SHOULD AID CLOUD DEVELOPMENT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 240 AM EDT MON AUG 10 2015 THE 500MB TROUGH SET UP ACROSS MUCH OF EASTERN CANADA AND THE EASTERN US. THE LAST SHORTWAVE OVER W LAKE SUPERIOR AT 12Z TUESDAY WILL EXPAND ACROSS E UPPER MI THROUGH THE AFTERNOON AND EVENING HOURS. WHILE THIS AND THE STEADY N-NNW WINDS WILL KEEP CLOUDS STUCK OVER THE E HALF...LINGERING PRECIP IS STILL UNKNOWN ESPECIALLY WITH PW VALUES DIMINISHING THROUGH FROM A MAX OF AROUND 1.25 EARLY IN THE DAY TO AROUND 1 IN BY MID AFTERNOON TUESDAY. THE SFC HIGH STRETCHING FROM HUDSON BAY DOWN THROUGH THE CENTRAL PLAINS TUESDAY MORNING WILL SETTLE ACROSS THE CWA BY 06Z WEDNESDAY. THE CANADIAN/ECMWF/AND GFS ARE ALL BRINGING IN ADDITIONAL PRECIP WEDNESDAY ASSOCIATED WITH A WARM FRONT EXTENDING FROM A LOW WAY UP IN N CENTRAL CANADA. THIS WILL COINCIDE WITH THE SFC RIDGE SHIFTING SLIGHTLY TO THE SE. THE NAM IS LESS IMPRESSIVE...AND HAS ONLY INCREASED CLOUD COVER. GIVEN THE OVERALL LIMITED MOISTURE...WILL KEEP POPS TO A MINIMUM. THE SFC LOW WILL SHIFT E AND STRETCH FROM N CANADA THROUGH HUDSON BAY BY THURSDAY AFTERNOON...WITH THE COLD FRONT SET UP ACROSS ONTARIO...NW LAKE SUPERIOR AND CENTRAL MN. LOOK FOR A BETTER CHANCE OF SHOWERS THURSDAY AS THE FRONT ROLLS THROUGH...SHIFTING SE OF THE CWA BY MID MORNING FRIDAY. INCREASED WIND GUSTS A BIT MORE DUE TO INCREASED MIXING AROUND THE COLD FRONT. LOOK FOR HIGH PRESSURE TO QUICKLY BUILD IN FRIDAY...AND REMAIN THROUGH SATURDAY...WITH DRY WEATHER FIGURED. WAA WILL BEGIN AGAIN SATURDAY NIGHT AS THE LARGE AREA OF HIGH PRESSURE SHIFTS E. THE ECMWF IS QUICKER TO HAVE THE HIGH SHIFT E IN ADVANCE OF THE NEXT CANADIAN LOW AND ASSOCIATED COLD FRONT FOR SUNDAY-MONDAY. WILL GO WITH A GENERAL BLEND FOR THE WEEKEND ON THE TIMING. WHILE TS MAY BE MORE ALIGNED NEAR THE COLD FRONT...WILL GO WITH GENERAL SHOWERS AND THUNDERSTORMS AT THIS POINT...WHICH WILL NEED TO BE FINE TUNED AS THE TIME NEARS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 119 AM EDT MON AUG 10 2015 SCT SHOWERS INTO CENTRAL UPPER MICHIGAN MAY STILL BRUSH KSAW EARLY IN THE TAF PERIOD. OTHERWISE...MAINLY DRY CONDITIONS ARE EXPECTED OVERNIGHT AT KCMX/KIWD. ONCE THE COLD FRONT MOVES THROUGH THE AREA OVERNIGHT AND BREAKS IN THE CLOUDS OCCUR...EXPECT SOME SHALLOW FOG TO DEVELOP AT ALL THREE TERMINALS...ESPECIALLY AT KSAW WHERE RAIN FELL AND THE LIGHTEST WINDS WILL OCCUR. THE FCST IS NOT AS PESSIMISTIC FOR THE WEST TERMINALS...AS LOW LEVEL WINDS WILL SLOWLY BE INCREASING THROUGH THE NIGHT WHICH WILL RESULT IN MORE MIXING INTO THE DRIER AIR ALOFT. FOR TODAY...EXPECT CONDITIONS IMPROVING TO VFR THROUGH THE MORNING HOURS AS THE AREA IS IN BETWEEN THE DEPARTING FRONT AND ANOTHER UPPER LEVEL DISTURBANCE ARRIVING LATE AFTERNOON AND EVENING. SCT/ISOLD SHRA MAY BE POSSIBLE DURING THE EVENING BUT SHOULD HAVE LITTLE IMPACT ON CIGS/VSBY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 509 AM EDT MON AUG 10 2015 IN THE WAKE OF A COLD FRONT CROSSING THE UPPER LAKES...W TO NW WINDS WILL BEGIN TO INCREASE TODAY ACROSS LAKE SUPERIOR...THOUGH WINDS WILL REMAIN UNDER 20KT. ANY FOG OVER THE LAKE SHOULD GRADUALLY DISSIPATE. TONIGHT/TUE...PRES GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE TO 10-20KT OUT OF THE SW INTO THU AHEAD OF THE NEXT APPROACHING COLD FRONT. DEPENDING HOW MUCH THE PRES GRADIENT TIGHTENS...WILL NEED TO WATCH FOR THE POTENTIAL OF WINDS TO INCREASE FURTHER INTO THE 15-25KT RANGE...WITH PERHAPS GUSTS TO 30KT AT THE HIGHEST OBS PLATFORMS. WINDS WILL DIMINISH AFTER THE FRONT PASSES. EXPECT LIGHTER WINDS UNDER 15KT ON FRI AS HIGH PRES BUILDS INTO THE UPPER LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...JLB MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
240 AM EDT MON AUG 10 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 308 PM EDT SUN AUG 9 2015 MUCH OF THE FOCUS ON THE SHORT TERM FORECAST IS ON THE CONVECTIVE DEVELOPMENT EXPECTED OVER THE WEST/CENTRAL U.P. IN THE NEXT FEW HOURS AND CONTINUING INTO THE EVENING. A LARGE AREA OF MVFR CLOUDS HAS BEEN SETUP OVER NORTHWEST WISCONSIN AND WESTERN UPPER MICHIGAN THIS MORNING AND INTO THE EARLY AFTERNOON HOURS. THIS HAS HELPED SUPPRESS THE DIURNAL HEATING AND HAS KEPT ML CAPE VALUES OVER THE WESTERN THIRD OF THE U.P. BELOW 500 J/KG. FARTHER TO THE EAST AND ALONG THE EDGE OF THE LOW CLOUDS...DIURNAL CU HAS DEVELOPED AND RAP ANALYSIS DATA IS SHOWING 500-1000 J/KG OF ML CAPE. HAVE STARTED TO SEE SOME SHOWERS DEVELOP IN CENTRAL IRON COUNTY AND ALSO ALONG THE WISCONSIN BORDER SOUTH OF BESSEMER. THESE ARE OUT AHEAD OF THE COLD FRONT STRETCHING SOUTHWEST ACROSS WESTERN LAKE SUPERIOR AND INTO CENTRAL MINNESOTA. A SHORTWAVE HAS BEEN MOVING THROUGH CENTRAL MINNESOTA THIS MORNING AND INTO THE EARLY AFTERNOON HOURS...WHICH HAS BEEN THE MAIN FOCUS OF SHOWERS AND THUNDERSTORMS THUS FAR. WITH THE SHORTWAVE EXPECTED TO CONTINUE EASTWARD...THINK THE CWA WILL ONLY BE BRUSHED BY THE NORTHERN EDGE...BUT WITH THE SUPPORT OF THE WEAK COLD FRONT MOVING INTO THE WESTERN U.P. STILL THINK ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE THE REST OF THIS AFTERNOON INTO THIS EVENING. RAP MUCAPE VALUES EXCEED 1000 J/KG OVER THE WESTERN U.P. SO THERE IS STILL SOME SUPPORT FOR STRONGER STORMS IF THEY CAN GET GOING. UNFORTUNATELY MID CLOUDS FROM THE SHORTWAVE ARE MASKING THE LOWER CLOUD FIELD AND IT IS MAKING IT DIFFICULT TO SEE HOW DEVELOPMENT IS GOING...BUT AM ABLE TO MAKE OUT SOME SCATTERING OF THE LOW CLOUDS TO THE SOUTHWEST OF MARQUETTE COUNTY...SO THAT MAY BE ENOUGH TO GET SHOWERS DEVELOPING FURTHER AS THEY INTERACT WITH THE BETTER INSTABILITY JUST TO THE EAST. IN ADDITION...HAVE SEEN SOME HINTS OF A LAKE BREEZE NEAR MARQUETTE ON OBS AND RADAR...WHICH WILL LEAD TO SOME SHOWER DEVELOPMENT. ADJUSTED THE FORECAST EARLIER THIS MORNING WITH THE AXIS OF HIGHEST POPS TOWARDS THAT AREA AND WILL MAKE SLIGHT ADJUSTMENTS TO THAT AREA (SLIGHTLY TO THE WEST AND TOWARDS THE COLD FRONT) BEFORE FINAL ISSUANCE. THE FRONT WILL SLOWLY MOVE EAST ACROSS THE U.P. TONIGHT AND EXIT THE NEWBERRY/MANISTIQUE AREA A COUPLE HOURS AFTER SUNRISE. A LOT OF THE FORECAST FOR THIS EVENING WILL DEPEND ON THE DEVELOPMENT/COVERAGE OF THE SHOWERS AND THUNDERSTORMS OVER THE WESTERN/CENTRAL U.P....BUT THINK THE COMBINED FRONT AND SHORTWAVE WILL KEEP THE SCATTERED SHOWER POTENTIAL PUSHING EAST THROUGH THE AREA INTO THE FIRST PART OF THE OVERNIGHT HOURS...ESPECIALLY OVER THE CENTRAL. THEN...EXPECT SHOWERS TO DIMINISH OVERNIGHT AS THE COLD FRONT AND WEAK SHORTWAVE SHIFTS OFF TO THE EAST. THAT WILL LEAVE THE AREA BETWEEN THE DEPARTING COLD FRONT AND A HIGH BUILDING INTO THE NORTHERN PLAINS. WITH LIGHT WINDS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES BEHIND THE FRONT...EXPECT THERE TO BE SOME FOG DEVELOPMENT OVERNIGHT...ESPECIALLY OVER THE CENTRAL. THE WEST AND EAST THIRDS WILL BE A LITTLE MORE UNCERTAIN...DUE TO THE POTENTIAL FOR LESS LOW LEVEL MOISTENING FROM RAIN AND CLOUD COVER FROM THE DEPARTING SHORTWAVE OVER THE EAST AND INCREASING LOW LEVEL NORTH-NORTHWESTERLY FLOW OVER THE WEST. THOSE NORTHERLY WINDS WILL INCREASE THROUGH THE MORNING TOMORROW AS THE FRONT MOVES AWAY FROM THE AREA AND THE HIGH BUILDS INTO THE NORTHERLY PLAINS. OVERALL...IT SHOULDN/T BE TOO WINDY WITH MOSTLY LOCATIONS SEEING GUSTS AROUND 10-12KTS. WITH THE WINDS AIDING MIXING AND DIURNAL HEATING...SHOULD SEE THE FOG THAT DEVELOPS OVERNIGHT TRANSITION TO SOME DIURNAL CU THROUGH THE MORNING AND EARLY AFTERNOON HOURS. MODELS SHOWING LIMITED MOISTURE THAT IT IS MIXING INTO...SO WOULDN/T EXPECT THE COVERAGE TO BE MORE THAN PARTLY CLOUDY. THERE CONTINUES TO BE INDICATIONS IN THE HIGHER RESOLUTION MODELS THAT ISOLATED SHOWERS WILL DEVELOP OVER THE SOUTH CENTRAL IN THE AFTERNOON AND ALSO AROUND OR JUST SOUTHEAST OF KERY. THERE IS BETTER MOISTURE LINGERING IN THAT AREA AND INDICATIONS OF MLCAPE VALUES RISING TOWARDS 300 J/KG. FINALLY...DEEPER MOISTURE ARRIVES LATE IN THE DAY FROM THE NORTHWEST AS A 700-500MB TROUGH DROPS SOUTHEAST AROUND THE DISSIPATING JAMES BAY UPPER LOW. WITH THE STRENGTH OF THE WAVE...COULD SEE A FEW SHOWERS DROP SOUTHEAST ACROSS NORTHWEST LAKE SUPERIOR LATE IN THE DAY AND MAYBE APPROACH THE KEWEENAW PENINSULA. HAVE LEFT THE SLIGHT CHANCES JUST TO THE NORTHWEST OF THE KEWEENAW FOR NOW...AS THE BEST OPPORTUNITY WOULD COME AFTER 00Z. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 240 AM EDT MON AUG 10 2015 THE 500MB TROUGH SET UP ACROSS MUCH OF EASTERN CANADA AND THE EASTERN US. THE LAST SHORTWAVE OVER W LAKE SUPERIOR AT 12Z TUESDAY WILL EXPAND ACROSS E UPPER MI THROUGH THE AFTERNOON AND EVENING HOURS. WHILE THIS AND THE STEADY N-NNW WINDS WILL KEEP CLOUDS STUCK OVER THE E HALF...LINGERING PRECIP IS STILL UNKNOWN ESPECIALLY WITH PW VALUES DIMINISHING THROUGH FROM A MAX OF AROUND 1.25 EARLY IN THE DAY TO AROUND 1 IN BY MID AFTERNOON TUESDAY. THE SFC HIGH STRETCHING FROM HUDSON BAY DOWN THROUGH THE CENTRAL PLAINS TUESDAY MORNING WILL SETTLE ACROSS THE CWA BY 06Z WEDNESDAY. THE CANADIAN/ECMWF/AND GFS ARE ALL BRINGING IN ADDITIONAL PRECIP WEDNESDAY ASSOCIATED WITH A WARM FRONT EXTENDING FROM A LOW WAY UP IN N CENTRAL CANADA. THIS WILL COINCIDE WITH THE SFC RIDGE SHIFTING SLIGHTLY TO THE SE. THE NAM IS LESS IMPRESSIVE...AND HAS ONLY INCREASED CLOUD COVER. GIVEN THE OVERALL LIMITED MOISTURE...WILL KEEP POPS TO A MINIMUM. THE SFC LOW WILL SHIFT E AND STRETCH FROM N CANADA THROUGH HUDSON BAY BY THURSDAY AFTERNOON...WITH THE COLD FRONT SET UP ACROSS ONTARIO...NW LAKE SUPERIOR AND CENTRAL MN. LOOK FOR A BETTER CHANCE OF SHOWERS THURSDAY AS THE FRONT ROLLS THROUGH...SHIFTING SE OF THE CWA BY MID MORNING FRIDAY. INCREASED WIND GUSTS A BIT MORE DUE TO INCREASED MIXING AROUND THE COLD FRONT. LOOK FOR HIGH PRESSURE TO QUICKLY BUILD IN FRIDAY...AND REMAIN THROUGH SATURDAY...WITH DRY WEATHER FIGURED. WAA WILL BEGIN AGAIN SATURDAY NIGHT AS THE LARGE AREA OF HIGH PRESSURE SHIFTS E. THE ECMWF IS QUICKER TO HAVE THE HIGH SHIFT E IN ADVANCE OF THE NEXT CANADIAN LOW AND ASSOCIATED COLD FRONT FOR SUNDAY-MONDAY. WILL GO WITH A GENERAL BLEND FOR THE WEEKEND ON THE TIMING. WHILE TS MAY BE MORE ALIGNED NEAR THE COLD FRONT...WILL GO WITH GENERAL SHOWERS AND THUNDERSTORMS AT THIS POINT...WHICH WILL NEED TO BE FINE TUNED AS THE TIME NEARS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 119 AM EDT MON AUG 10 2015 SCT SHOWERS INTO CENTRAL UPPER MICHIGAN MAY STILL BRUSH KSAW EARLY IN THE TAF PERIOD. OTHERWISE...MAINLY DRY CONDITIONS ARE EXPECTED OVERNIGHT AT KCMX/KIWD. ONCE THE COLD FRONT MOVES THROUGH THE AREA OVERNIGHT AND BREAKS IN THE CLOUDS OCCUR...EXPECT SOME SHALLOW FOG TO DEVELOP AT ALL THREE TERMINALS...ESPECIALLY AT KSAW WHERE RAIN FELL AND THE LIGHTEST WINDS WILL OCCUR. THE FCST IS NOT AS PESSIMISTIC FOR THE WEST TERMINALS...AS LOW LEVEL WINDS WILL SLOWLY BE INCREASING THROUGH THE NIGHT WHICH WILL RESULT IN MORE MIXING INTO THE DRIER AIR ALOFT. FOR TODAY...EXPECT CONDITIONS IMPROVING TO VFR THROUGH THE MORNING HOURS AS THE AREA IS IN BETWEEN THE DEPARTING FRONT AND ANOTHER UPPER LEVEL DISTURBANCE ARRIVING LATE AFTERNOON AND EVENING. SCT/ISOLD SHRA MAY BE POSSIBLE DURING THE EVENING BUT SHOULD HAVE LITTLE IMPACT ON CIGS/VSBY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 308 PM EDT SUN AUG 9 2015 A COLD FRONT MOVING ACROSS WEST-CENTRAL LAKE SUPERIOR AT THIS TIME WILL PUSH EAST ACROSS THE REST OF THE LAKE TONIGHT WILL LEAD TO A WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY A WEAK PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT THRU MON. PATCHY TO AREAS OF FOG HAS BEEN OBSERVED ON SATELLITE FOR PORTIONS OF THE LAKE AND EXPECT THAT TO DIMINISH TONIGHT INTO MONDAY AS SLIGHTLY DRIER AIR ARRIVES BEHIND THE FRONT. MON NIGHT/TUE...THE GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE SOME OUT OF THE SOUTHWEST INTO THU AHEAD OF THE NEXT APPROACHING COLD FRONT. THAT FRONT WILL SHIFT WINDS TO THE NORTHWEST FOR FRIDAY...BUT SHOULD STAY BELOW 20KTS AT HIGH PRESSURE BUILDS BACK OVER THE AREA. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KF AVIATION...JLB MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
124 AM EDT MON AUG 10 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 326 PM EDT SUN AUG 9 2015 SHOWERS AND THUNDERSTORMS CHANCES WILL INCREASE TONIGHT INTO MONDAY. MANY AREAS SHOULD SEE AROUND A HALF INCH OF RAIN IN THIS PERIOD... HOWEVER SEVERE WEATHER IS GENERALLY NOT EXPECTED. A FEW SHOWERS MAY LINGER INTO MONDAY EVENING...BUT WE SHOULD GRADUALLY DRY OUT... MAKING FOR A PLEASANT TUESDAY WITH LESS HUMIDITY. MUCH OF THE REMAINDER OF THE WEEK LOOKS DRY WITH NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES...WITH DAYTIME HIGHS GENERALLY 80 TO 85. A WIDELY SCATTERED THUNDERSTORM WILL BE POSSIBLE ON THURSDAY. && .UPDATE... ISSUED AT 1050 PM EDT SUN AUG 9 2015 I HAVE UPDATED THE FORECAST TO INCREASE THE RISK FOR THUNDERSTORMS TOWARD MORNING OVER OUR SOUTHWEST CWA THEN SPREAD THAT CONVECTION EASTWARD. WE ALREADY HAD LIKELY POP FOR MONDAY MORNING AFTER 8 AM...SO THIS JUST STARTS THE CONVECTION A TOUCH SOONER. WHAT I AM SEEING FROM BOTH THE WATER VAPOR IMAGE LOOPS AND WATCHING THE RAP MODEL HOURLY IS THAT WE HAVE A JET EXIT REGION WITH DECENT PVU (POTENTIAL VORTICITY) IN THE 500 TO 300 MB LAYER COMING THROUGH THE I-94 TO I-96 AREA BETWEEN 4 AM AND 9 AM THIS MORNING. A WEAK LLJ DEVELOPS IN RESPONSE TO THIS AIMED AT AZO BTW 8 AM AND 10 AM. SINCE THE HRRR...HRRR EXPERIMENTAL...AND RAP13 HAVE BEEN RATHER CONSISTENT WITH THIS AND IT MAKES SENSE GIVEN WHAT IS GOING ON NOW... I AM DID UPDATE THE GRIDS TO REFLECT THE IDEA OF THUNDERSTORMS TOWARD MORNING. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 326 PM EDT SUN AUG 9 2015 RAIN CHANCES OVER SW MI WILL PEAK DURING THE FIRST HALF OF MONDAY AS A COLD FRONT APPROACHES. GIVEN THE FRONT/S TIMING SEVERE WEATHER IS GENERALLY NOT EXPECTED. WE DRY OUT MONDAY EVENING...BECOMING COOLER AND LESS HUMID INTO TUESDAY. A COLD FRONT WAS MOVING ACROSS THE MN/WI BORDER THIS AFTERNOON AND HAS AN AREA OF SHOWERS AND STORMS WITH IT. THE STRONGEST AREA OF STORMS WAS ASSOCIATED WITH THE LEFT EXIT REGION OF THE UPPER JET. THE FRONT AND THE UPPER JET WILL MAKE IT/S WAY THROUGH THE CWA MONDAY MORNING INTO EARLY AFTERNOON...NORMALLY A MIN TIME FOR SEVERE WX. THIS LIKELY FAVORS AREAS TO OUR EAST FOR THE POTENTIAL OF STRONGER STORMS. THE OTHER PARAMETER GOING AGAINST SEVERE STORMS IS THAT THE 0-6 KM BULK SHEAR IS ONLY 20-25 KNOTS OVER SW MI AS THE FRONT COMES THROUGH. HOWEVER THE FRONT WILL BE HEADING INTO A JUICY AIR MASS WITH DEW POINTS AROUND 70 ALONG I-94...AND MID TO UPPER 60S ELSEWHERE ACROSS THE CWA. SO EXPECT THE STORMS OVER MN/WI TO HOLD TOGETHER AND EXPAND...BRINGING A BENEFICIAL RAIN TO MOST OF THE CWA LATE TONIGHT INTO MONDAY. RAIN TOTALS WILL VARY GREATLY GIVEN THE CONVECTIVE NATURE...BUT MOST AREAS SHOULD SEE A HALF TO THREE QUARTERS OF INCH OF RAIN. THE SHOWERS AND STORMS WILL END FROM WEST TO EAST WITH THE FRONTAL PASSAGE MONDAY AFTERNOON INTO THE EVENING. COOLER AND LESS HUMID AIR WILL FILTER IN BEHIND THE FRONT. HIGHS IN THE 70S CAN BE EXPECTED FOR TUESDAY AS THE UPPER FLOW BECOMES NORTHWESTERLY. OUTSIDE CHANCE THAT A FEW SHOWERS MAY POP UP ACROSS CENTRAL LOWER TUESDAY DUE TO THE COOL AIR ALOFT. I DID NOT ADD THIS...BUT I DID INCREASE THE CLOUD COVER IN THE FORECAST. WE SHOULD SEE DIURNAL CU AT THE VERY LEAST...WHICH SHOULD BECOME BKN TO OVC AT TIMES DURING THE AFTERNOON. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 326 PM EDT SUN AUG 9 2015 FAIR WEATHER IS ANTICIPATED WEDNESDAY WITH A HIGH PRESSURE RIDGE CENTERED OVER THE LOWER GREAT LAKES REGION STILL IN CONTROL OF THE WX PATTERN. IT WILL TURN WARMER AND MORE HUMID THURSDAY IN SW FLOW OUT AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL BRING A CHANCE OF RAIN AND THUNDERSTORMS LATE THURSDAY THROUGH THURSDAY NIGHT INTO FRIDAY. FAIR WX WILL RETURN BEHIND THAT SYSTEM FOR FRIDAY NIGHT THROUGH THE WEEKEND AS A HIGH PRESSURE RIDGE BUILDS SLOWLY EAST ACROSS THE GREAT LAKES REGION. TEMPERATURES NEXT WEEKEND WILL AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 123 AM EDT MON AUG 10 2015 SCATTERED SHOWERS WILL CONTINUE TO DEVELOP OVERNIGHT AS SOUTH FLOW AHEAD OF A COLD FRONT INCREASES. MVFR CIGS/VSBYS POSSIBLE PRIOR TO AND JUST AFTER SUNRISE. A COLD FRONT MAY TRIGGER NON SEVERE STORMS THIS AFTERNOON...ESPECIALLY NEAR THE EASTERN TAF SITES. && .MARINE... ISSUED AT 326 PM EDT SUN AUG 9 2015 RATHER QUIET CONDITIONS ARE EXPECTED ON THE TONIGHT INTO MONDAY. HOWEVER NORTHERLY WINDS WILL INCREASE BEHIND THE FRONT AND WAVES WILL BEGIN TO BUILD MONDAY EVENING INTO TUESDAY. PEAK WINDS AND WAVES SHOULD OCCUR INTO TUESDAY...AND WE MAY NEED A SMALL CRAFT ADVISORY BY TUESDAY AFTERNOON. WINDS AND WAVES SHOULD THEN DIMINISH LATE TUESDAY NIGHT. && .HYDROLOGY... ISSUED AT 326 PM EDT SUN AUG 9 2015 NO HYDRO IMPACTS ARE EXPECTED OVER THE NEXT WEEK. THE CHANCE FOR SCATTERED SHOWERS WILL INCREASE THROUGH THE AFTERNOON AND ESPECIALLY THE EVENING. RAIN CHANCES ARE HIGHEST THIS EVENING INTO MONDAY AFTERNOON ALONG WITH THE POTENTIAL FOR ISOLATED STORMS. STORM CHANCES WILL BE HIGHEST EARLY MONDAY AFTERNOON ACROSS THE EASTERN FORECAST AREA. WE COULD SEE A FEW STRONG STORMS AT THAT TIME CAPABLE OF LOCALLY HIGHER RAINFALL AMOUNTS. BUT IN GENERAL...WIDESPREAD RAINFALL IS FORECAST TO REMAIN BELOW 0.75 INCHES AND MOST LIKELY IN THE 0.25 TO 0.50 INCH RANGE. ANY RAINFALL TONIGHT INTO MONDAY WILL LIKELY BE BENEFICIAL FOR MOST. OUTLOOK...THE REST OF THE WORK WEEK LOOKS QUIET AND MAINLY DRY. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...JK SHORT TERM...JK LONG TERM...LAURENS AVIATION...04 HYDROLOGY...EBW MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
119 AM EDT MON AUG 10 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 308 PM EDT SUN AUG 9 2015 MUCH OF THE FOCUS ON THE SHORT TERM FORECAST IS ON THE CONVECTIVE DEVELOPMENT EXPECTED OVER THE WEST/CENTRAL U.P. IN THE NEXT FEW HOURS AND CONTINUING INTO THE EVENING. A LARGE AREA OF MVFR CLOUDS HAS BEEN SETUP OVER NORTHWEST WISCONSIN AND WESTERN UPPER MICHIGAN THIS MORNING AND INTO THE EARLY AFTERNOON HOURS. THIS HAS HELPED SUPPRESS THE DIURNAL HEATING AND HAS KEPT ML CAPE VALUES OVER THE WESTERN THIRD OF THE U.P. BELOW 500 J/KG. FARTHER TO THE EAST AND ALONG THE EDGE OF THE LOW CLOUDS...DIURNAL CU HAS DEVELOPED AND RAP ANALYSIS DATA IS SHOWING 500-1000 J/KG OF ML CAPE. HAVE STARTED TO SEE SOME SHOWERS DEVELOP IN CENTRAL IRON COUNTY AND ALSO ALONG THE WISCONSIN BORDER SOUTH OF BESSEMER. THESE ARE OUT AHEAD OF THE COLD FRONT STRETCHING SOUTHWEST ACROSS WESTERN LAKE SUPERIOR AND INTO CENTRAL MINNESOTA. A SHORTWAVE HAS BEEN MOVING THROUGH CENTRAL MINNESOTA THIS MORNING AND INTO THE EARLY AFTERNOON HOURS...WHICH HAS BEEN THE MAIN FOCUS OF SHOWERS AND THUNDERSTORMS THUS FAR. WITH THE SHORTWAVE EXPECTED TO CONTINUE EASTWARD...THINK THE CWA WILL ONLY BE BRUSHED BY THE NORTHERN EDGE...BUT WITH THE SUPPORT OF THE WEAK COLD FRONT MOVING INTO THE WESTERN U.P. STILL THINK ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE THE REST OF THIS AFTERNOON INTO THIS EVENING. RAP MUCAPE VALUES EXCEED 1000 J/KG OVER THE WESTERN U.P. SO THERE IS STILL SOME SUPPORT FOR STRONGER STORMS IF THEY CAN GET GOING. UNFORTUNATELY MID CLOUDS FROM THE SHORTWAVE ARE MASKING THE LOWER CLOUD FIELD AND IT IS MAKING IT DIFFICULT TO SEE HOW DEVELOPMENT IS GOING...BUT AM ABLE TO MAKE OUT SOME SCATTERING OF THE LOW CLOUDS TO THE SOUTHWEST OF MARQUETTE COUNTY...SO THAT MAY BE ENOUGH TO GET SHOWERS DEVELOPING FURTHER AS THEY INTERACT WITH THE BETTER INSTABILITY JUST TO THE EAST. IN ADDITION...HAVE SEEN SOME HINTS OF A LAKE BREEZE NEAR MARQUETTE ON OBS AND RADAR...WHICH WILL LEAD TO SOME SHOWER DEVELOPMENT. ADJUSTED THE FORECAST EARLIER THIS MORNING WITH THE AXIS OF HIGHEST POPS TOWARDS THAT AREA AND WILL MAKE SLIGHT ADJUSTMENTS TO THAT AREA (SLIGHTLY TO THE WEST AND TOWARDS THE COLD FRONT) BEFORE FINAL ISSUANCE. THE FRONT WILL SLOWLY MOVE EAST ACROSS THE U.P. TONIGHT AND EXIT THE NEWBERRY/MANISTIQUE AREA A COUPLE HOURS AFTER SUNRISE. A LOT OF THE FORECAST FOR THIS EVENING WILL DEPEND ON THE DEVELOPMENT/COVERAGE OF THE SHOWERS AND THUNDERSTORMS OVER THE WESTERN/CENTRAL U.P....BUT THINK THE COMBINED FRONT AND SHORTWAVE WILL KEEP THE SCATTERED SHOWER POTENTIAL PUSHING EAST THROUGH THE AREA INTO THE FIRST PART OF THE OVERNIGHT HOURS...ESPECIALLY OVER THE CENTRAL. THEN...EXPECT SHOWERS TO DIMINISH OVERNIGHT AS THE COLD FRONT AND WEAK SHORTWAVE SHIFTS OFF TO THE EAST. THAT WILL LEAVE THE AREA BETWEEN THE DEPARTING COLD FRONT AND A HIGH BUILDING INTO THE NORTHERN PLAINS. WITH LIGHT WINDS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES BEHIND THE FRONT...EXPECT THERE TO BE SOME FOG DEVELOPMENT OVERNIGHT...ESPECIALLY OVER THE CENTRAL. THE WEST AND EAST THIRDS WILL BE A LITTLE MORE UNCERTAIN...DUE TO THE POTENTIAL FOR LESS LOW LEVEL MOISTENING FROM RAIN AND CLOUD COVER FROM THE DEPARTING SHORTWAVE OVER THE EAST AND INCREASING LOW LEVEL NORTH-NORTHWESTERLY FLOW OVER THE WEST. THOSE NORTHERLY WINDS WILL INCREASE THROUGH THE MORNING TOMORROW AS THE FRONT MOVES AWAY FROM THE AREA AND THE HIGH BUILDS INTO THE NORTHERLY PLAINS. OVERALL...IT SHOULDN/T BE TOO WINDY WITH MOSTLY LOCATIONS SEEING GUSTS AROUND 10-12KTS. WITH THE WINDS AIDING MIXING AND DIURNAL HEATING...SHOULD SEE THE FOG THAT DEVELOPS OVERNIGHT TRANSITION TO SOME DIURNAL CU THROUGH THE MORNING AND EARLY AFTERNOON HOURS. MODELS SHOWING LIMITED MOISTURE THAT IT IS MIXING INTO...SO WOULDN/T EXPECT THE COVERAGE TO BE MORE THAN PARTLY CLOUDY. THERE CONTINUES TO BE INDICATIONS IN THE HIGHER RESOLUTION MODELS THAT ISOLATED SHOWERS WILL DEVELOP OVER THE SOUTH CENTRAL IN THE AFTERNOON AND ALSO AROUND OR JUST SOUTHEAST OF KERY. THERE IS BETTER MOISTURE LINGERING IN THAT AREA AND INDICATIONS OF MLCAPE VALUES RISING TOWARDS 300 J/KG. FINALLY...DEEPER MOISTURE ARRIVES LATE IN THE DAY FROM THE NORTHWEST AS A 700-500MB TROUGH DROPS SOUTHEAST AROUND THE DISSIPATING JAMES BAY UPPER LOW. WITH THE STRENGTH OF THE WAVE...COULD SEE A FEW SHOWERS DROP SOUTHEAST ACROSS NORTHWEST LAKE SUPERIOR LATE IN THE DAY AND MAYBE APPROACH THE KEWEENAW PENINSULA. HAVE LEFT THE SLIGHT CHANCES JUST TO THE NORTHWEST OF THE KEWEENAW FOR NOW...AS THE BEST OPPORTUNITY WOULD COME AFTER 00Z. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 332 PM EDT SUN AUG 9 2015 A NW FLOW BTWN AN UPR RDG IN THE PLAINS AND A DOWNSTREAM TROF OVER ERN CANADA WL DOMINATE THE GREAT LKS EARLY THIS WEEK...BRINGING A PERIOD OF BLO NORMAL TEMPS FOR MON NGT INTO WED. WARMER WX AND A CHC OF SHOWERS/TS WL THEN BE THE RULE ON THU IN ADVANCE OF A COLD FNT ASSOCIATED WITH A DISTURBANCE DROPPING SEWD THRU NW ONTARIO. EXPECT DRY AND A BIT COOLER WX LATE IN THE WEEK WITH HI PRES TRAILING THE FNT. THE NEXT CHC OF SHOWERS/TS AND WARMER WX WL RETURN NEXT SUN AHEAD OF THE NEXT SHRTWV/COLD FNT TOPPING THE PERSISTENT UPR RDG IN THE PLAINS. MON NGT...SHRTWV DIVING SEWD IN THE NW FLOW ALF BTWN PLAINS RDG AND ERN TROF IS FCST TO DIG THRU THE AREA. SOME OF THE MODELS SHOW SOME WEAK DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE PVA AHEAD OF THIS DISTURBANCE AND GENERATE SOME SPOTTY LGT PCPN OVER THE AREA...MAINLY OVER THE HIER TERRAIN NEAR LK SUP WITH UPSLOPE N WINDS. BUT ABSENCE OF STRONGER FORCING AND ARRIVAL OF THIS DISTURBANCE DURING PERIOD OF NOCTURNAL COOLING WL LIMIT INTENSITY AND COVERAGE OF ANY SHOWERS. DO EXPECT MORE LO CLDS IN THESE UPSLOPE AREAS WITH AN INCRS IN LLVL RH AS H85 TEMPS WITHIN THERMAL TROF FALL TO 8-10C BY 12Z TUE. STEADY N WINDS WL LIMIT THE DIURNAL TEMP FALL DESPITE THE LLVL COOLING TREND. MOST PLACES SHOULD SEE MINS IN THE 50S...WITH THE LOWER TEMPS AT THE COOLER SPOTS OVER THE INTERIOR W HALF WHERE THE WINDS WL BE A BIT LIGHTER CLOSER TO SFC HI PRES RDG BLDG INTO MN. TUE/TUE NGT...EXPECT DRY WX TO PREVAIL DURING THIS TIME UNDER CONFLUENT NW FLOW ALF/DEEP LYR QVECTOR DVGC/SUBSIDENCE LEFT IN THE WAKE OF EXITING SHRTWV. SC IN THE UPSLOPE AREAS ON TUE MRNG SHOULD EXPAND WITH DAYTIME HEATING UNDER THERMAL TROF...BUT CLOSER APRCH OF SFC HI PRES FCST TO ARRIVE OVER THE W BY 00Z WED/INCRSGLY ACYC LLVL FLOW/LOWERING SUBSIDENCE INVRN WL LIKELY RESULT IN MORE SUNSHINE W-E THRU THE AFTN. UNDER MOCLR SKIES...TUE NGT WL BE COOL ESPECIALLY OVER THE INTERIOR W HALF WITH LIGHTER WINDS CLOSER TO SFC HI PRES RDG SINKING INTO WI. BUT WITH MIN PWAT NOT MUCH BLO 0.75 INCH IN THIS AREA...DO NOT EXPECT MIN TEMPS TO BE TOO CHILLY. WED/WED NGT...SFC HI PRES IS FCST TO SINK S INTO THE MID MS RIVER VALLEY THRU THIS TIME. AS THE MSLP FALLS OVER NW ONTARIO IN ADVANCE OF SHRTWV RIDING OVER THE TOP OF PLAINS RDG INTO FAR NW ONTARIO... UPR MI WL BE DOMINATED BY AN INCRSG WSW FLOW. EXPECT SOME CLDS ASSOCIATED WITH BAND OF INCRSG WAA/ISENTROPIC ASCENT BEST SHOWN ON THE 300-305K SFCS TO IMPACT THE UPR LKS WED AFTN/EVNG. MANY OF THE MODELS GENERATE SOME PCPN AS WELL...BUT RELATIVE DRYNESS OF THE LLVLS AND MODEST PWAT FCST NEAR 1 INCH /ABOUT NORMAL/ WARRANT ONLY LO CHC POPS. THU/THU NGT...SHRTWV OVER FAR NW ONTARIO AT 12Z THU IS PROGGED TO SLIDE SE INTO WRN QUEBEC THU NGT AND DRAG A COLD FNT ACRS UPR MI SOMETIME THU AFTN/EVNG. ARRIVAL OF THIS BNDRY/BAND OF MODEST DEEP LYR FORCING AT A TIME WHEN DAYTIME HEATING WL HAVE AN IMPACT FAVORS SOME SHOWERS/TS...BUT ABSENCE OF MUCH IN THE WAY OF HGT FALLS WELL TO THE SW OF TRACK OF SHRTWV/SHARPEST FORCING...QUESTIONS ABOUT DEGREE OF MSTR INFLOW AHEAD OF THE FNT AND TIMING DIFFERENCES AMONG THE MODELS ON FROPA TIMING WARRANT NO HIER THAN LO CHC POPS ATTM. THU LOOKS TO BE A WARM DAY WITH H85 TEMPS PUSHING 18-20C AHEAD OF THE FNT. EXTENDED...HI PRES TRAILING THE COLD FROPA WL BRING MOCLR WX FOR FRI AND SAT. FRI WL BE COOLER WITH H85 TEMPS DIPPING TO ARND 14C...BUT THEN SAT WL TURN WARMER AS THE HI SHIFTS TO THE E AND RETURN SSW FLOW LIFTS H85 TEMPS UP TO 16C. THE NEXT CHC OF SHOWERS/TS WL ARRIVE ON SUN AHEAD OF NEXT DISTURBANCE RIDING OVER THE PLAINS RDG. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 119 AM EDT MON AUG 10 2015 SCT SHOWERS INTO CENTRAL UPPER MICHIGAN MAY STILL BRUSH KSAW EARLY IN THE TAF PERIOD. OTHERWISE...MAINLY DRY CONDITIONS ARE EXPECTED OVERNIGHT AT KCMX/KIWD. ONCE THE COLD FRONT MOVES THROUGH THE AREA OVERNIGHT AND BREAKS IN THE CLOUDS OCCUR...EXPECT SOME SHALLOW FOG TO DEVELOP AT ALL THREE TERMINALS...ESPECIALLY AT KSAW WHERE RAIN FELL AND THE LIGHTEST WINDS WILL OCCUR. THE FCST IS NOT AS PESSIMISTIC FOR THE WEST TERMINALS...AS LOW LEVEL WINDS WILL SLOWLY BE INCREASING THROUGH THE NIGHT WHICH WILL RESULT IN MORE MIXING INTO THE DRIER AIR ALOFT. FOR TODAY...EXPECT CONDITIONS IMPROVING TO VFR THROUGH THE MORNING HOURS AS THE AREA IS IN BETWEEN THE DEPARTING FRONT AND ANOTHER UPPER LEVEL DISTURBANCE ARRIVING LATE AFTERNOON AND EVENING. SCT/ISOLD SHRA MAY BE POSSIBLE DURING THE EVENING BUT SHOULD HAVE LITTLE IMPACT ON CIGS/VSBY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 308 PM EDT SUN AUG 9 2015 A COLD FRONT MOVING ACROSS WEST-CENTRAL LAKE SUPERIOR AT THIS TIME WILL PUSH EAST ACROSS THE REST OF THE LAKE TONIGHT WILL LEAD TO A WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY A WEAK PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT THRU MON. PATCHY TO AREAS OF FOG HAS BEEN OBSERVED ON SATELLITE FOR PORTIONS OF THE LAKE AND EXPECT THAT TO DIMINISH TONIGHT INTO MONDAY AS SLIGHTLY DRIER AIR ARRIVES BEHIND THE FRONT. MON NIGHT/TUE...THE GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE SOME OUT OF THE SOUTHWEST INTO THU AHEAD OF THE NEXT APPROACHING COLD FRONT. THAT FRONT WILL SHIFT WINDS TO THE NORTHWEST FOR FRIDAY...BUT SHOULD STAY BELOW 20KTS AT HIGH PRESSURE BUILDS BACK OVER THE AREA. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KC AVIATION...JLB MARINE...SRF
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
346 AM CDT MON AUG 10 2015 .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 332 AM CDT MON AUG 10 2015 SHORT RANGE GUIDANCE SEEMS TO BE IN GOOD AGREEMENT WITH CURRENT RADAR TRENDS IN CONTINUING TO PUSH THE BAND OF CONVECTION SOUTH OF OUR CWFA BY 12Z. UPSTREAM DEVELOPMENT OVER SOUTHWEST MISSOURI LOOKS LIKE IT SHOULD STAY OUT OF OUR AREA...BUT WE MAY STILL GET CLIPPED SO HAVE KEPT MID-HIGH CHANCE POPS GOING PAST 12Z ACROSS SOUTHERN ZONES. FURTHER NORTH, SHORT RANGE GUIDANCE HAS CONSISTENTLY BEEN WEAKENING THE CONVECTION NOW MOVING INTO NORTHWEST MISSOURI OUT OF IOWA, AND CURRENT RADAR TRENDS SUPPORT THIS AS WELL. THAT BEING SAID, ISOLATED TO WIDELY SCATTERED STORMS WILL CONTINUE TO BE POSSIBLE ACROSS THROUGH THE MORNING FROM I-70 NORTHWARD. THE ACTUAL SYNOPTIC COLD FRONT IS DIFFICULT TO FIND AT THIS TIME, BUT LOOKS LIKE IT SHOULD PUSH THROUGH THE AREA FROM MID MORNING THROUGH THE AFTERNOON. RAP HAS THE 850MB FLOW TURNING SHARPLY TO THE NORTH- NORTHWEST WITH DECENT COLD ADVECTION (FOR AUGUST) BEHIND IT. SHOULD STILL BE ENOUGH INSTABILITY TO CONTINUE A CHANCE OF THUNDERSTORMS THROUGH THE AFTERNOON INTO EARLY EVENING. STUCK PRETTY CLOSE TO GUIDANCE FOR TEMPERATURES TODAY...THOUGH HIGHS WILL BE DIFFICULT TO PIN DOWN DUE TO AFTERNOON CONVECTION. CARNEY .LONG TERM: (TONIGHT THROUGH SUNDAY) ISSUED AT 345 AM CDT MON AUG 10 2015 EXPECT A FEW SHOWERS OR THUNDERSTORMS TO LINGER INTO EARLY THIS EVENING, BUT SHOULD BE GONE BEFORE MIDNIGHT. DRIER AIR IS FORECAST TO BUILD ACROSS THE AREA BEHIND THE FRONT TONIGHT AND TUESAY...AND LAST AT LEAST THROUGH THE END OF THE WEEK WITH DEWPOINT TEMPERATURES DROPPING INTO THE 60S. A HIGH AMPLITUDE UPPER LEVEL PATTERN LOCKS THE DRY LOW LEVEL RIDGE OVER THE MISSISSIPPI VALLEY, SO PRECIPITATION CHANCES ARE VIRTUALLY NIL. THIS SHOULD MAKE FOR RELATIVELY COMFORTABLE WEATHER FOR WHAT ARE TYPICALLY THE DOG-DAYS OF SUMMER WITH HIGHS NEAR OR A FEW DEGREES BELOW NORMAL IN THE MID TO UPPER 80S AND LOWS WELL BELOW NORMAL IN THE 60S. CARNEY && .AVIATION: (FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1056 PM CDT SUN AUG 9 2015 BACKBUILDING MCS JUST EAST AND SOUTH OF THE ST LOUIS METRO AREA. THERE MAY CONTINUE TO BE ISOLATED SHOWERS/STORMS IMPACTING THE ST LOUIS AREA TAFS UNTIL AROUND 08Z MON. COULD NOT RULE OUT SOME ADDITIONAL DEVELOPMENT AS WELL LATE TONIGHT/EARLY MONDAY MORNING AS A COLD FRONT MOVES SOUTHWARD THROUGH OUR AREA LATE TONIGHT AND MONDAY MORNING. S-SWLY SURFACE WINDS WILL VEER AROUND TO A N-NWLY DIRECTION AFTER FROPA. THE MODEL MOS GUIDANCE WAS HINTING AT POST FRONTAL MVFR CLOUD CEILINGS MAINLY EARLY MONDAY MORNING. SPECIFICS FOR KSTL: ISOLATED SHOWERS AND STORMS MAY CONTINUE TO IMPACT STL LATE TONIGHT DUE TO BACKBUILDING MCS AND AS A COLD FRONT MOVES SOUTHWARD THROUGH STL AREA AROUND 12Z MONDAY. S-SWLY SURFACE WINDS WILL VEER AROUND TO A NWLY DIRECTION AFTER FROPA EARLY MONDAY MORNING. THERE WILL ALSO LIKELY BE POST FRONTAL MVFR CIGS MONDAY MORNING. GKS && .PRELIMINARY POINT TEMPS/POPS: SAINT LOUIS 88 72 86 68 / 40 30 10 5 QUINCY 83 64 84 62 / 40 30 5 0 COLUMBIA 87 67 85 63 / 40 30 5 0 JEFFERSON CITY 89 68 86 63 / 40 30 5 0 SALEM 86 70 84 63 / 40 30 10 5 FARMINGTON 86 69 84 61 / 40 30 10 0 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
333 AM CDT MON AUG 10 2015 .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 332 AM CDT MON AUG 10 2015 SHORT RANGE GUIDANCE SEEMS TO BE IN GOOD AGREEMENT WITH CURRENT RADAR TRENDS IN CONTINUING TO PUSH THE BAND OF CONVECTION SOUTH OF OUR CWFA BY 12Z. UPSTREAM DEVELOPMENT OVER SOUTHWEST MISSOURI LOOKS LIKE IT SHOULD STAY OUT OF OUR AREA...BUT WE MAY STILL GET CLIPPED SO HAVE KEPT MID-HIGH CHANCE POPS GOING PAST 12Z ACROSS SOUTHERN ZONES. FURTHER NORTH, SHORT RANGE GUIDANCE HAS CONSISTENTLY BEEN WEAKENING THE CONVECTION NOW MOVING INTO NORTHWEST MISSOURI OUT OF IOWA, AND CURRENT RADAR TRENDS SUPPORT THIS AS WELL. THAT BEING SAID, ISOLATED TO WIDELY SCATTERED STORMS WILL CONTINUE TO BE POSSIBLE ACROSS THROUGH THE MORNING FROM I-70 NORTHWARD. THE ACTUAL SYNOPTIC COLD FRONT IS DIFFICULT TO FIND AT THIS TIME, BUT LOOKS LIKE IT SHOULD PUSH THROUGH THE AREA FROM MID MORNING THROUGH THE AFTERNOON. RAP HAS THE 850MB FLOW TURNING SHARPLY TO THE NORTH- NORTHWEST WITH DECENT COLD ADVECTION (FOR AUGUST) BEHIND IT. SHOULD STILL BE ENOUGH INSTABILITY TO CONTINUE A CHANCE OF THUNDERSTORMS THROUGH THE AFTERNOON INTO EARLY EVENING. STUCK PRETTY CLOSE TO GUIDANCE FOR TEMPERATURES TODAY...THOUGH HIGHS WILL BE DIFFICULT TO PIN DOWN DUE TO AFTERNOON CONVECTION. CARNEY .LONG TERM: (MONDAY THROUGH NEXT SUNDAY) ISSUED AT 325 PM CDT SUN AUG 9 2015 (MONDAY THROUGH WEDNESDAY) UPPER FLOW WILL BEGIN TO TURN OUT OF THE NORTHWEST BY TOMORROW AS UPPER HIGH OVER OVER SOUTHERN HIGH PLAINS BEGINS TO BUILDS AND TROUGH DIGS IN OVER THE NORTHEASTERN CONUS. THIS WILL HELP PUSH THE SURFACE COLD FRONT THROUGH THE CWA EARLY IN THE DAY MONDAY. BOTH THE NAM AND GFS ARE SHOWING A WEAK SHORTWAVE TROUGH MOVING ACROSS MISSOURI AND ILLINOIS MIDDAY MONDAY. THE ASCENT FROM THE TROUGH SHOULD BE ENOUGH TO PRODUCE A FEW SHOWERS AND THUNDERSTORMS IN THE INSTABILITY GENERATED BY MIDDAY OVER THE SOUTHERN CWA. ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS DURING THE AFTERNOON AS A SECONDARY TROUGH MOVES ACROSS IOWA. CHANCES FOR RAIN WILL DECREASE TUESDAY AND WEDNESDAY AS THE UPPER FLOW CONTINUES TO AMPLIFY AND THE VERTICAL MOTION BECOMES MORE SUBSIDENT AS HIGH PRESSURE BUILDS INTO THE AREA. MOS TEMPERATURES THE NEXT FEW DAYS ARE IN REASONABLE AGREEMENT WITH EACH OTHER AND WITH MIXING UP TO THE 900-800MB LAYER...SO HAVE GENERALLY FOLLOWED THEM. (THURSDAY THROUGH SUNDAY) EXPECT A DRY PERIOD AS AREA WILL BE DOMINATED BY A LARGE AREA OF SURFACE HIGH PRESSURE UNDER NORTHWESTERLY UPPER FLOW ALOFT. 850MB TEMPERATURES FROM THE GFS ENSEMBLE MEAN WILL BE IN THE 12-18C RANGE WHICH SUPPORTS HIGHS IN THE 80S. BRITT && .AVIATION: (FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1056 PM CDT SUN AUG 9 2015 BACKBUILDING MCS JUST EAST AND SOUTH OF THE ST LOUIS METRO AREA. THERE MAY CONTINUE TO BE ISOLATED SHOWERS/STORMS IMPACTING THE ST LOUIS AREA TAFS UNTIL AROUND 08Z MON. COULD NOT RULE OUT SOME ADDITIONAL DEVELOPMENT AS WELL LATE TONIGHT/EARLY MONDAY MORNING AS A COLD FRONT MOVES SOUTHWARD THROUGH OUR AREA LATE TONIGHT AND MONDAY MORNING. S-SWLY SURFACE WINDS WILL VEER AROUND TO A N-NWLY DIRECTION AFTER FROPA. THE MODEL MOS GUIDANCE WAS HINTING AT POST FRONTAL MVFR CLOUD CEILINGS MAINLY EARLY MONDAY MORNING. SPECIFICS FOR KSTL: ISOLATED SHOWERS AND STORMS MAY CONTINUE TO IMPACT STL LATE TONIGHT DUE TO BACKBUILDING MCS AND AS A COLD FRONT MOVES SOUTHWARD THROUGH STL AREA AROUND 12Z MONDAY. S-SWLY SURFACE WINDS WILL VEER AROUND TO A NWLY DIRECTION AFTER FROPA EARLY MONDAY MORNING. THERE WILL ALSO LIKELY BE POST FRONTAL MVFR CIGS MONDAY MORNING. GKS && .PRELIMINARY POINT TEMPS/POPS: SAINT LOUIS 88 72 86 68 / 40 30 10 5 QUINCY 83 64 84 62 / 40 30 5 0 COLUMBIA 87 67 85 63 / 40 30 5 0 JEFFERSON CITY 89 68 86 63 / 40 30 5 0 SALEM 86 70 84 63 / 40 30 10 5 FARMINGTON 86 69 84 61 / 40 30 10 0 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1225 AM CDT MON AUG 10 2015 .SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 333 PM CDT SUN AUG 9 2015 CHANCE FOR THUNDERSTORMS AND THEIR SEVERITY TONIGHT ARE THE PRIMARY FORECAST CONCERNS. THUNDERSTORMS WERE FIRING AT MID AFTERNOON ALONG A WEAK SURFACE BOUNDARY STRETCHING FROM SOUTHEAST SOUTH DAKOTA INTO WESTERN NEBRASKA. THESE STORMS HAVE PLENTY OF INSTABILITY AND SHEAR TO FEED ON...SOME 2500 J/KG OF MLCAPE AND 40KT OF EFFECTIVE BULK SHEAR...AS PER LATEST RAP OBJECTIVE ANALYSIS. ALREADY GETTING REPORTS OF SEVERE HAIL JUST WEST OF OUR AREA WHERE VIGOROUS UPDRAFTS WERE SEEN. AND FREEZING LEVELS ARE QUITE A BIT LOWER THAN LAST EVENING. SO A CONTINUED HAIL THREAT IS CERTAINLY EXPECTED...WITH MODEST MICROBURST POTENTIAL ALSO NOTED ON RAP PROGS. PERHAPS A BIGGER SHOW WITH POTENTIALLY MORE WIDESPREAD SEVERE LATER THIS EVENING IS POSSIBLE. MID LEVEL SHORTWAVE DIVING INTO WESTERN SOUTH DAKOTA WILL CONTINUE SOUTHEAST THIS EVENING...PUSHING A COLD FRONT ALONG WITH IT. SHEAR PROFILES SHOULD ACTUALLY INCREASE IN MAGNITUDE GIVEN MID LEVEL SPEED MAX TIED TO WAVE. SHEAR VECTORS ARE LINING UP NEARLY PARALLEL WITH EXPECTED FRONTAL/CONVECTIVE LINE...SUPPORTING MORE OF A LINEAR STORM MODE. WIND FIELDS...PREDICTED DOWNDRAFT CAPE AND LAYER THETA-E DIFFERENCES APPROACHING 30 ALL SUGGEST SEVERE WIND POTENTIAL AS LINE RACES INTO EASTERN NEBRASKA. SEVERAL MESOSCALE HI-RES MODELS ARE OFFERING VARIED OPINIONS AROUND THIS LINE OF THINKING...SO WILL HIT EVENING THUNDER CHANCES PRETTY HARD. EXPECT STORMS TO SLOWLY DIE OFF LATER THIS EVENING AND OVERNIGHT AS THEY APPROACH INTERSTATE 80 AND BEYOND...HOWEVER SEVERE THREAT APPEARS TO LINGER FOR SOME TIME AFTER DARK. BY MONDAY MORNING LINGERING STORMS SHOULD BE EXITING OUR SOUTHEAST CWA. HOWEVER WEAK IMPULSE IN MID LEVEL FLOW COULD TAP WANING INSTABILITY IN THE MID AFTERNOON TO PRODUCE A STORM OR TWO IN SOUTHWEST IOWA. THEN NORTHERLY SURFACE FLOW UNDER HIGH PRESSURE WILL FORETELL A RELATIVELY DRY PERIOD OVER THE NEXT COUPLE OF DAYS. HIGHS BOTH TUESDAY AND WEDNESDAY WILL GRADUALLY INCREASE INTO THE LOWER AND MIDDLE 80S UNDER PLENTY OF SUNSHINE. AND DEW POINTS SHOULD BE LOWER ON TUESDAY BEFORE BEGINNING TO RETURN WEDNESDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 333 PM CDT SUN AUG 9 2015 OUR RELATIVELY QUIET WEATHER PATTERN IS EXPECTED TO CONTINUE THROUGH THE REST OF THE WEEK. MID LEVEL HIGH PRESSURE RIDGE IS FORECAST BY BOTH ECMWF AND GFS TO BUILD FROM THE SOUTHERN PLAINS INTO THE NORTHERN ROCKIES...AND EXPAND A BIT TO THE EAST. THIS WILL TAKE MAIN STORM TRACK NORTH AND EAST OF OUR AREA...AND ALLOW FOR WARMER TEMPERATURES BOTH AT THE SURFACE AND ALOFT. WILL MAINTAIN OUR DRY FORECAST UNTIL MAYBE SATURDAY NIGHT OR SUNDAY WHEN RIDGE IS FORECAST TO BEGIN TO BREAK DOWN. HIGHS MAINLY IN THE UPPER 80S AND LOWER 90S SHOULD PREVAIL. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1223 AM CDT MON AUG 10 2015 THUNDERSTORMS AFFECTING KOMA WERE MOVING AWAY AND WILL EAST/SOUTHEAST OF THE TAF SITE BEFORE 06Z. OTHERWISE...THERE WILL BE A CHANCE OF ADDITIONAL THUNDERSTORMS IN THE AREA...BUT NOT CONFIDENT ENOUGH THAT STORMS WOULD DIRECTLY IMPACT ANY TAF LOCATIONS. OCCASIONAL MVFR CONDITIONS AT ALL THREE TAF SITES THROUGH ABOUT 13-15Z...THEN VFR AFTER THAT. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
133 AM EDT MON AUG 10 2015 .SYNOPSIS... DRY WEATHER AND SEASONAL TEMPERATURES WILL CONTINUE TONIGHT AND MONDAY AS HIGH PRESSURE REMAINS OVER THE REGION, BUT CONDITIONS TAKE A TURN FOR THE WORSE MONDAY NIGHT THROUGH TUESDAY NIGHT AS LOW PRESSURE TRACKS OVER THE REGION. A WIDESPREAD RAIN EVENT IS EXPECTED WITH STORM TOTALS OF A HALF TO ONE AND A HALF INCHES OF RAIN. CHANCES FOR SHOWERS CONTINUE INTO WEDNESDAY BEFORE DRIER CONDITIONS RETURN FOR THE END OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 116 AM EDT MONDAY...UPDATED TO CAPTURE LATEST TEMP/DWPT/WIND AND SKY CONDITIONS. SOME PATCHY FOG ALREADY DEVELOPING WILL CONTINUE TO SPREAD IN AREAL COVERAGE ACRS THE DEEPER PROTECTED RIVER VALLEYS WITH TEMPS FALLING BACK INTO THE U40S DACKS TO L/M 50S SLV/NEK/CENTRAL VT TO NEAR 60F CPV. MINOR ADJUSTMENTS TO SKY COVER AND MINIMUM TEMPERATURES (REALLY AT THE NOISE LEVEL) TO COVER CURRENT OBSERVATIONAL TRENDS. A FEW SPOTS IN THE ST LAWRENCE VALLEY WERE ALREADY WITHIN A DEGREE OF FORECAST MINIMUM TEMPERATURES SO I DID LOWER THOSE VALUES BY A FEW DEGREES. ALSO INCORPORATED LATEST RAP UPPER LEVEL RH PROGS INTO THE CLOUD FORECAST OVERNIGHT, SHOWING AT LEAST SOME CI/CS OVERSPREADING THE REGION FROM WEST TO EAST AFTER MIDNIGHT, THOUGH BY AND LARGE CLEAR TO PARTLY CLOUDY SKIES WILL STILL BE THE PREVAILING RULE. HAVE A GREAT NIGHT. PRIOR DISCUSSION FROM 738 PM EDT SUNDAY... MINOR ADJUSTMENTS TO FORECAST AS OF 700 PM, MAINLY TO KEEP 10-20% POPS ACROSS NC/NE VT THROUGH 9 PM OR SO TO ACCOUNT FOR CURRENT WIDELY SCT SHOWER ACTIVITY WHICH HAS SURPRISINGLY INCREASED IN AREAL COVERAGE OVER THE PAST HOUR OR SO. THIS ACTIVITY IS DEVELOPING IN WEAKLY CONVERGENT LOW TO MID LEVEL FLOW ALONG A DIFFUSE SFC TROUGH/BACKDOOR FRONT ORIENTED NNW TO SSE ACROSS SOUTHERN QUEBEC INTO NORTHEASTERN VT AND SOUTHWARD INTO CENTRAL NH WHERE IT BECOMES DIFFICULT TO IDENTIFY. GIVEN THIS ACTIVITY AND ALLOWING FOR SCATTERED AREAS OF WET GROUND TO FOSTER ENHANCED SFC MOISTURE FLUXES OVERNIGHT I ALSO INTRODUCED SLIGHTLY HIGHER COVERAGE OF BR/FG ACROSS THIS AREA WHICH LATEST BTV4/BTV6 KM OUTPUT SHOWS QUITE NICELY. OTHERWISE INHERITED FORECAST REMAINS IN GOOD SHAPE SHOWING MAINLY CLR/PTLY CLOUDY SKIES OVERNIGHT (OUTSIDE THE FOG) AS TEMPERATURES BOTTOM OUT IN THE 50S TO AROUND 60 BY SUNRISE MONDAY. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... AS OF 355 PM EDT SUNDAY...MONDAY WILL BE OUR LAST DAY OF THIS NICE STRETCH OF WEATHER AS ALL AVAILABLE GUIDANCE IS IN GOOD AGREEMENT SHOWING THE BEST LOW/MID LEVEL MOISTURE AND FORCING ASSOCIATED WITH OUR NEXT SYSTEM IS WEST OF THE AREA THROUGH 00Z TUESDAY. AFTER MORNING FOG BURNS OFF WE`LL SEE INCREASING CLOUDS FROM THE WEST WHICH MAY TEMPER AFTERNOON TEMPS, BUT PROGGED 850MB TEMPS OF 12-14C WILL SUPPORT HIGHS IN THE UPPER 70S MOUNTAINS TO LOW/MID 80S IN THE VALLEYS. AS MENTIONED, ALL GUIDANCE IS IN GOOD AGREEMENT HANDLING A DEEPENING MID/UPPER TROUGH ACROSS THE GREAT LAKES AND SURFACE LOW TRACKING FROM THE OHIO VALLEY MONDAY NIGHT AND ACROSS THE BTV CWA TUESDAY. 00Z GFS CAME AROUND TO THE NAM/ECMWF/CMC SLOWER TIMING AND THE 12Z RUNS SLOWED THE ARRIVAL OF DEEP LAYER MOISTURE EVEN FURTHER TO NOW AFTER MIDNIGHT. HEAVIEST QPF AXIS CONTINUES TO POINT TOWARDS NORTHERN NEW YORK WHERE 1-1.5" STORM TOTAL IS EXPECTED THROUGH TUESDAY, WHILE POINTS EASTWARD WILL BE GENERALLY LESS THAN AN INCH WITH SOME DOWNSLOPING EFFECTS EXPECTED ACROSS PORTIONS OF THE GREEN MOUNTAINS ASSOCIATED WITH A LOW LEVEL SOUTHEASTERLY JET OF 40-50 KNOTS IMPACTING THE AREA TUESDAY. SOUNDINGS CONTINUE TO SHOW THESE RIDGETOP WINDS ARE ABOVE THE INVERSION LEVEL AROUND 2000 FT, SO NOT EXPECTING STRONG GUSTS REACHING THE SURFACE, BUT 25-35 MPH SEEM REASONABLE ALONG THE FAVORED LOCALES OF THE WESTERN SLOPES FROM RUTLAND TO UNDERHILL. CAN`T RULE OUT A FEW RUMBLES OF THUNDER THROUGH THE EVENT EITHER WITH MODELS SHOWING SOME SLIGHT ELEVATED INSTABILITY BUT AREAL COVERAGE SHOULD BE PRETTY LIMITED. TUESDAY NIGHT THE SURFACE LOW TRACKS EAST OF THE REGION WITH A MID- LEVEL DRY SLOT SHIFTING OVER THE REGION. PRECIP WILL END FROM WEST TO EAST BY MIDNIGHT, WITH CONDITIONS GENERALLY DRY THROUGH SUNRISE. MID-LEVEL HEIGHTS/THICKNESS DON`T FALL MUCH SO IT WILL BE A MILD NIGHT UNDER PLENTY OF CLOUD COVER WITH LOWS IN THE UPPER 50S TO MID 60S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 259 PM EDT SUNDAY...UNSETTLED WEATHER CONTINUES THROUGH THE EXTENDED PERIOD WITH UPPER TROUGH REMAINING IN PLACE OVER THE NORTHEAST AND PASSAGE OF ANOTHER SURFACE FRONT ON FRIDAY. STARTING 12Z WEDNESDAY...SURFACE FRONT WILL HAVE PASSED ON TO THE EAST WITH A WESTERLY LOW LEVEL FLOW. 500 MB TROUGH LAGGING BEHIND SURFACE FEATURE AND WILL BE SETTLING IN ON WEDNESDAY. COMBINATION OF COLD POOL ALOFT, LOW LEVEL UPSLOPE FLOW, AND MOISTURE TRAPPED IN THE LOW LEVELS WILL RESULT IN MAINLY DAYTIME SHOWERS IN THE RESULTING INSTABILITY AND LIFT. IF ANY TIME WILL BE QUIET IT WOULD BE THURSDAY WHEN THE REGION IS BETWEEN SYSTEMS. UPPER LOW GETS KICKED OUT AS NEXT LOW APPROACHES, AND AN AREA OF SHORTWAVE RIDGING PASSES OVER. WESTERLY UPSLOPE LOW LEVEL FLOW TURNS MORE SOUTHERLY BY END OF DAY, AND A BAND OF DRIER AIR MOVES IN TO MINIMIZE CHANCES FOR RAIN. FRIDAY HAS RAIN CHANCES AGAIN WHEN COLD FRONT MOVES THROUGH AT THE SURFACE AGAIN AND UPPER SHORTWAVE THAT MOVED DOWN IN THE NORTHWEST FLOW DROPS INTO THE BASE OF THE MEAN TROUGH. CHANCE FOR SHOWERS INTO SATURDAY WITH SAME POST FRONTAL SCENARIO OF INSTABILITY DRIVEN BY COLD POOL ALOFT AND LIFT FROM LOW LEVEL UPSLOPE FLOW. MENTIONED THUNDER ON WEDNESDAY AND FRIDAY AS CAPE, MEAGER THOUGH IT IS, INCREASES TO 250-500 J/KG AND COULD GET ENOUGH VERTICAL DEVELOPMENT FOR LIGHTNING. NOT MUCH CHANGE IN TEMPERATURES THROUGHOUT, WE NEVER GET MUCH CHANCE TO WARM APPRECIABLY, AND THE AIR BEHIND THE FRONTS IS NOT PARTICULARLY COOL EITHER. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... THROUGH 06Z TUESDAY...MAINLY VFR EXPECTED...WITH THE EXCEPTION OF SOME IFR/LIFR FOG/BR OVERNIGHT INTO EARLY MONDAY MORNING AT MPV/SLK/MSS. SCT CUMULUS FIELD WILL GRADUALLY DIMINISH OVERNIGHT. THIS CLEARING WILL ALLOW FOR THE FORMATION OF FOG/BR AT SLK/MPV/MSS. DENSEST AND MOST PERSISTENT FOG EXPECTED AT MPV BETWEEN 07Z AND 13Z. AFTER 12-13Z MONDAY MORNING EXPECTING BOTH SCATTERED HIGH CIRRUS TO FILTER ACROSS AS WELL AS THE DEVELOPMENT OF ADDITIONAL CUMULUS CLOUDS BY AFTERNOON. CLOUD COVERAGE INCREASES AREA-WIDE MONDAY EVENING. A FEW RAIN SHOWERS ARE POSSIBLE AT SLK AFTER 21Z. COVERAGE OF RAIN SHOWERS INCREASES ACROSS NORTHERN NY BETWEEN 00-06Z TUESDAY...AFFECTING SLK/MSS/PBG. LIGHT AND LOCALLY VARIABLE WINDS (EXCEPT SE DRAINAGE AT RUT) BECOME SOUTHERLY FROM 5-8 KNOTS ON MONDAY. OUTLOOK 06Z TUESDAY THROUGH FRIDAY... 06Z TUE - 00Z WED...DETERIORATING CONDITIONS LIKELY (MVFR POSSIBLE IFR) WITH PERIODS OF RAIN SHOWERS AND STRATUS. 00Z WED - 00Z THU...VFR WITH PERIODS OF MVFR IN LINGERING SCATTERED SHOWERS. 00Z THU - 00Z FRI...VFR WITH A FEW SCATTERED RAIN SHOWERS STILL POSSIBLE. 00Z FRI ONWARD...VFR WITH PERIODS MVFR IN SCATTERED SHOWERS ALONG A COLD FRONT...MAINLY AFTER 18Z. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...LAHIFF NEAR TERM...JMG/TABER SHORT TERM...LAHIFF LONG TERM...HANSON AVIATION...RJS/MUCCILLI
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
118 AM EDT MON AUG 10 2015 .SYNOPSIS... DRY WEATHER AND SEASONAL TEMPERATURES WILL CONTINUE TONIGHT AND MONDAY AS HIGH PRESSURE REMAINS OVER THE REGION, BUT CONDITIONS TAKE A TURN FOR THE WORSE MONDAY NIGHT THROUGH TUESDAY NIGHT AS LOW PRESSURE TRACKS OVER THE REGION. A WIDESPREAD RAIN EVENT IS EXPECTED WITH STORM TOTALS OF A HALF TO ONE AND A HALF INCHES OF RAIN. CHANCES FOR SHOWERS CONTINUE INTO WEDNESDAY BEFORE DRIER CONDITIONS RETURN FOR THE END OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 116 AM EDT MONDAY...UPDATED TO CAPTURE LATEST TEMP/DWPT/WIND AND SKY CONDITIONS. SOME PATCHY FOG ALREADY DEVELOPING WILL CONTINUE TO SPREAD IN AREAL COVERAGE ACRS THE DEEPER PROTECTED RIVER VALLEYS WITH TEMPS FALLING BACK INTO THE U40S DACKS TO L/M 50S SLV/NEK/CENTRAL VT TO NEAR 60F CPV. MINOR ADJUSTMENTS TO SKY COVER AND MINIMUM TEMPERATURES (REALLY AT THE NOISE LEVEL) TO COVER CURRENT OBSERVATIONAL TRENDS. A FEW SPOTS IN THE ST LAWRENCE VALLEY WERE ALREADY WITHIN A DEGREE OF FORECAST MINIMUM TEMPERATURES SO I DID LOWER THOSE VALUES BY A FEW DEGREES. ALSO INCORPORATED LATEST RAP UPPER LEVEL RH PROGS INTO THE CLOUD FORECAST OVERNIGHT, SHOWING AT LEAST SOME CI/CS OVERSPREADING THE REGION FROM WEST TO EAST AFTER MIDNIGHT, THOUGH BY AND LARGE CLEAR TO PARTLY CLOUDY SKIES WILL STILL BE THE PREVAILING RULE. HAVE A GREAT NIGHT. PRIOR DISCUSSION FROM 738 PM EDT SUNDAY... MINOR ADJUSTMENTS TO FORECAST AS OF 700 PM, MAINLY TO KEEP 10-20% POPS ACROSS NC/NE VT THROUGH 9 PM OR SO TO ACCOUNT FOR CURRENT WIDELY SCT SHOWER ACTIVITY WHICH HAS SURPRISINGLY INCREASED IN AREAL COVERAGE OVER THE PAST HOUR OR SO. THIS ACTIVITY IS DEVELOPING IN WEAKLY CONVERGENT LOW TO MID LEVEL FLOW ALONG A DIFFUSE SFC TROUGH/BACKDOOR FRONT ORIENTED NNW TO SSE ACROSS SOUTHERN QUEBEC INTO NORTHEASTERN VT AND SOUTHWARD INTO CENTRAL NH WHERE IT BECOMES DIFFICULT TO IDENTIFY. GIVEN THIS ACTIVITY AND ALLOWING FOR SCATTERED AREAS OF WET GROUND TO FOSTER ENHANCED SFC MOISTURE FLUXES OVERNIGHT I ALSO INTRODUCED SLIGHTLY HIGHER COVERAGE OF BR/FG ACROSS THIS AREA WHICH LATEST BTV4/BTV6 KM OUTPUT SHOWS QUITE NICELY. OTHERWISE INHERITED FORECAST REMAINS IN GOOD SHAPE SHOWING MAINLY CLR/PTLY CLOUDY SKIES OVERNIGHT (OUTSIDE THE FOG) AS TEMPERATURES BOTTOM OUT IN THE 50S TO AROUND 60 BY SUNRISE MONDAY. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... AS OF 355 PM EDT SUNDAY...MONDAY WILL BE OUR LAST DAY OF THIS NICE STRETCH OF WEATHER AS ALL AVAILABLE GUIDANCE IS IN GOOD AGREEMENT SHOWING THE BEST LOW/MID LEVEL MOISTURE AND FORCING ASSOCIATED WITH OUR NEXT SYSTEM IS WEST OF THE AREA THROUGH 00Z TUESDAY. AFTER MORNING FOG BURNS OFF WE`LL SEE INCREASING CLOUDS FROM THE WEST WHICH MAY TEMPER AFTERNOON TEMPS, BUT PROGGED 850MB TEMPS OF 12-14C WILL SUPPORT HIGHS IN THE UPPER 70S MOUNTAINS TO LOW/MID 80S IN THE VALLEYS. AS MENTIONED, ALL GUIDANCE IS IN GOOD AGREEMENT HANDLING A DEEPENING MID/UPPER TROUGH ACROSS THE GREAT LAKES AND SURFACE LOW TRACKING FROM THE OHIO VALLEY MONDAY NIGHT AND ACROSS THE BTV CWA TUESDAY. 00Z GFS CAME AROUND TO THE NAM/ECMWF/CMC SLOWER TIMING AND THE 12Z RUNS SLOWED THE ARRIVAL OF DEEP LAYER MOISTURE EVEN FURTHER TO NOW AFTER MIDNIGHT. HEAVIEST QPF AXIS CONTINUES TO POINT TOWARDS NORTHERN NEW YORK WHERE 1-1.5" STORM TOTAL IS EXPECTED THROUGH TUESDAY, WHILE POINTS EASTWARD WILL BE GENERALLY LESS THAN AN INCH WITH SOME DOWNSLOPING EFFECTS EXPECTED ACROSS PORTIONS OF THE GREEN MOUNTAINS ASSOCIATED WITH A LOW LEVEL SOUTHEASTERLY JET OF 40-50 KNOTS IMPACTING THE AREA TUESDAY. SOUNDINGS CONTINUE TO SHOW THESE RIDGETOP WINDS ARE ABOVE THE INVERSION LEVEL AROUND 2000 FT, SO NOT EXPECTING STRONG GUSTS REACHING THE SURFACE, BUT 25-35 MPH SEEM REASONABLE ALONG THE FAVORED LOCALES OF THE WESTERN SLOPES FROM RUTLAND TO UNDERHILL. CAN`T RULE OUT A FEW RUMBLES OF THUNDER THROUGH THE EVENT EITHER WITH MODELS SHOWING SOME SLIGHT ELEVATED INSTABILITY BUT AREAL COVERAGE SHOULD BE PRETTY LIMITED. TUESDAY NIGHT THE SURFACE LOW TRACKS EAST OF THE REGION WITH A MID- LEVEL DRY SLOT SHIFTING OVER THE REGION. PRECIP WILL END FROM WEST TO EAST BY MIDNIGHT, WITH CONDITIONS GENERALLY DRY THROUGH SUNRISE. MID-LEVEL HEIGHTS/THICKNESS DON`T FALL MUCH SO IT WILL BE A MILD NIGHT UNDER PLENTY OF CLOUD COVER WITH LOWS IN THE UPPER 50S TO MID 60S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 259 PM EDT SUNDAY...UNSETTLED WEATHER CONTINUES THROUGH THE EXTENDED PERIOD WITH UPPER TROUGH REMAINING IN PLACE OVER THE NORTHEAST AND PASSAGE OF ANOTHER SURFACE FRONT ON FRIDAY. STARTING 12Z WEDNESDAY...SURFACE FRONT WILL HAVE PASSED ON TO THE EAST WITH A WESTERLY LOW LEVEL FLOW. 500 MB TROUGH LAGGING BEHIND SURFACE FEATURE AND WILL BE SETTLING IN ON WEDNESDAY. COMBINATION OF COLD POOL ALOFT, LOW LEVEL UPSLOPE FLOW, AND MOISTURE TRAPPED IN THE LOW LEVELS WILL RESULT IN MAINLY DAYTIME SHOWERS IN THE RESULTING INSTABILITY AND LIFT. IF ANY TIME WILL BE QUIET IT WOULD BE THURSDAY WHEN THE REGION IS BETWEEN SYSTEMS. UPPER LOW GETS KICKED OUT AS NEXT LOW APPROACHES, AND AN AREA OF SHORTWAVE RIDGING PASSES OVER. WESTERLY UPSLOPE LOW LEVEL FLOW TURNS MORE SOUTHERLY BY END OF DAY, AND A BAND OF DRIER AIR MOVES IN TO MINIMIZE CHANCES FOR RAIN. FRIDAY HAS RAIN CHANCES AGAIN WHEN COLD FRONT MOVES THROUGH AT THE SURFACE AGAIN AND UPPER SHORTWAVE THAT MOVED DOWN IN THE NORTHWEST FLOW DROPS INTO THE BASE OF THE MEAN TROUGH. CHANCE FOR SHOWERS INTO SATURDAY WITH SAME POST FRONTAL SCENARIO OF INSTABILITY DRIVEN BY COLD POOL ALOFT AND LIFT FROM LOW LEVEL UPSLOPE FLOW. MENTIONED THUNDER ON WEDNESDAY AND FRIDAY AS CAPE, MEAGER THOUGH IT IS, INCREASES TO 250-500 J/KG AND COULD GET ENOUGH VERTICAL DEVELOPMENT FOR LIGHTNING. NOT MUCH CHANGE IN TEMPERATURES THROUGHOUT, WE NEVER GET MUCH CHANCE TO WARM APPRECIABLY, AND THE AIR BEHIND THE FRONTS IS NOT PARTICULARLY COOL EITHER. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... THROUGH 00Z TUESDAY...MAINLY VFR EXPECTED...WITH THE EXCEPTION OF SOME IFR/LIFR FOG/BR AGAIN LATE TONIGHT/EARLY MONDAY MORNING AT MPV/SLK/MSS. SCT CUMULUS FIELD FROM THIS AFTERNOON AND EVENING WILL GRADUALLY DIMINISH THROUGH THE REMAINDER OF THE EVENING AND OVERNIGHT HOURS. THIS CLEARING WILL ALLOW FOR THE FORMATION OF FOG/BR AT SLK/MPV/MSS. DENSEST AND MOST PERSISTENT FOG EXPECTED AT MPV BETWEEN 07Z AND 13Z. AFTER 12-13Z MONDAY MORNING EXPECTING BOTH SCATTERED HIGH CIRRUS TO FILTER ACROSS AS WELL AS THE DEVELOPMENT OF ADDITIONAL CUMULUS CLOUDS BY AFTERNOON. A FEW SCATTERED RAIN SHOWERS ARE EVEN POSSIBLE AT SLK AFTER 21Z. LIGHT AND LOCALLY VARIABLE WINDS (EXCEPT SE DRAINAGE AT RUT) BECOME SOUTHERLY FROM 5-8 KNOTS ON MONDAY. OUTLOOK 00Z TUESDAY THROUGH FRIDAY... 00Z TUESDAY THROUGH 00Z WEDNESDAY...DETERIORATING CONDITIONS LIKELY (MVFR POSSIBLE IFR) WITH PERIODS OF RAIN SHOWERS AND STRATUS. 00Z WEDNESDAY THROUGH 00Z THURSDAY...VFR WITH PERIODS OF MVFR IN LINGERING SCATTERED SHOWERS. 00Z THURSDAY-00Z FRIDAY...VFR WITH A FEW SCATTERED RAIN SHOWERS STILL POSSIBLE. 00Z FRIDAY ONWARD...VFR WITH PERIODS MVFR IN SCATTERED SHOWERS ALONG A COLD FRONT...MAINLY AFTER 18Z. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...LAHIFF NEAR TERM...JMG/TABER SHORT TERM...LAHIFF LONG TERM...HANSON AVIATION...MUCCILLI
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
500 AM EDT MON AUG 10 2015 .SYNOPSIS... MUGGY TODAY. WEAK LOW PRESSURE DEVELOPS IN UPPER OHIO VALLEY MOVES NORTHEAST TONIGHT...DRAGGING A COLD FRONT THRU LATE TONIGHT AND TUESDAY MORNING. DRIER WITH COOLER NIGHTS WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... ONE OF THOSE MUGGY AUGUST DAYS...PROBABLY WISE/BEST...NOT TO RUN WITH ANY ONE MODEL SOLUTION. WITH ADJUSTMENTS BEING MADE DURING THE COURSE OF THE DAY AND EVENING BASED ON THE MOST RECENT CONVECTIVE TRENDS. AT 07Z...ONE MID LEVEL VORT MAX STRETCHED OUT FROM SRN WV NNW TOWARD ZZV. IT SHOULD EXIT TO OUR EAST 12Z TO 14Z. NOT MUCH VIRGA IN THIS AIRMASS...SO IT WAS CAUSING SOME DISORGANIZED AREAS OF RW- OR SPRINKLES THIS PREDAWN. ANOTHER DISTURBANCE DROPPING SE FROM WRN KY TOWARD MIDDLE TENNESSEE. EVEN THOUGH MAIN CONVECTIVE CLUSTERS WILL DROP INTO TN...FEEL SOME OF ITS AFFECTS... IN THIS MUGGY AIR...COULD RIPPLE EAST AND CAUSE SHOWERS TO FORM INTO OUR TRI STATE AND SW VA THIS MORNING. MATTER OF FACT...THE 00Z NAM HAD THE EQUILIBRIUM LEVEL QUICKLY REACHING TOWARD 35 THSD BY 15Z AT HTS. YET...IT DOES NOT GET ANY HIGHER...THIS AFTERNOON OR EVENING. WEAK SURFACE LOW EXPECTED TO FORM IN THE UPPER OHIO VALLEY...SAY OVER OHIO...THIS AFTERNOON. THE WEAK WIND FLOW DOES INCREASE...MAYBE SOME 15 KNOTS AT 925 MBS BY 21Z ON THE RAP IN THE OHIO VALLEY COUNTIES. THE 06Z NAM DEEPENS THIS CIRCULATION EVEN MORE WITH SOME 25 KNOTS BY 00Z TUESDAY. 700 MB FLOW ONLY INCREASES TO ABOUT 20 TO 25 KNOTS. EXPECT CELL MOVEMENT THIS AFTERNOON AND EVENING TO BE ABOUT 25 KNOTS...WHICH IS NOT TOO FAST...AND NOT TOO SLOW. WILL BASE FORECAST ON ASSOCIATED TROF/FRONT FORM THE EXITING WEAK LOW PRESSURE...TO REACH INTO OUR SE OHIO AROUND 06Z TUESDAY...THEN REACHING BETWEEN CKB AND EKN TO NEAR HTS BY 12Z TUESDAY. TRYING TO TIME THE PREFRONTAL CONVECTION THAT FORMS IN OHIO THIS AFTERNOON...AND HOW FAST TO PUSH THE HIGHER POPS EAST... THROUGH WEST VIRGINIA...IS ONE HEADACHE. TRIED TO HAVE LIKELY POPS LATE THIS AFTERNOON IN SE OHIO...REACHING OHIO RIVER AT 00Z TUESDAY...THEN TOWARD EKN TO CRW 03Z TO 06Z TUESDAY. COULD SEE SOME SEVERE STORM DEVELOPMENT IN THIS HUMID ENVIRONMENT NEAR OUR SE OHIO COUNTIES IN THE OHIO VALLEY LATE THIS AFTERNOON...THEN MOVE EAST THIS EVENING INTO WV. HOWEVER...AS OF THIS EARLY HOUR...COULD NOT HIGHLIGHT A SPECIFIC THREAT AREA. WOULD NOT BE SURPRISED IF SPC UPDATES ON DAY 1...INCLUDED SOME SLIGHT RISK AREAS...AS THIS WHOLE SYSTEM EVOLVES/DEVELOPS. OVERALL NOT TOO EXCITED WITH THE THIN CAPE AND RELATIVELY WEAK FLOW AS DISCUSSED. MOST COUNTIES...ESPECIALLY ALONG THE ROUTE 50 CORRIDOR COULD ACTUALLY USE SOME RAIN. MAXIMUM TEMPERATURE FORECAST TODAY DEPENDENT ON AFTERNOON COVERAGE OF CONVECTION... BUT TRIED TO STAY SLIGHTLY UNDER MOST 00Z MOS GUIDANCE...AND LOWER THAN THE OBSERVED ON SUNDAY. THE LOWEST CEILINGS SHOULD BE ASSOCIATED WITH THE FRONT...SO LEAVING LINGERING SHOWERS IN THE WAKE OF THE FRONT THRU 12Z TUESDAY NEAR THE OHIO RIVER...WITH SOME LIKELY POPS AT 12Z TUESDAY STILL OVER THE CENTRAL WV MOUNTAINS WITH THE FRONT. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... COLD FRONT WILL BE PUSHING EAST OF THE CWA BY MIDDAY TUESDAY. SEVERAL UPPER LEVEL SHORTWAVE TROUGHS WILL ROTATE AROUND A 500MB LOW OVER QUEBEC...SO LINGER POPS THROUGH MUCH OF THE DAY. OVERALL TROUGH AXIS PASSES LATE TUESDAY...HOWEVER NAM AND GFS SHOW ANOTHER RATHER POTENT SHORTWAVE TROUGH/VORT MAX DIGS IN ON WEDNESDAY. THE ECMWF KEEPS THINGS FARTHER NORTH. THIS FEATURE SHOULD BE FIGHTING INCREASINGLY DRIER AIR IN THE LOW LEVELS...BUT DID INCLUDE ISOLATED TO SCATTERED SHOWERS ACROSS NORTHERN AND EASTERN CWA. HIGH TEMPS WILL GENERALLY BE BELOW NORMAL THROUGH THE SHORT TERM. LOWS SHOULD BE JUST A TOUCH BELOW NORMAL TUESDAY NIGHT AS COLD AIR FILTERS IN...AND THEN A MILD 5-10 DEGREES BELOW NORMAL WEDNESDAY NIGHT. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE WEEKEND. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... ONE MID LEVEL DISTURBANCE MOVING THROUGH SRN WV AT 06Z WITH A FEW LIGHT SHOWERS. WIDESPREAD CLOUDS AT 4 TO 10 THSD FT SHOULD LIMITED COVERAGE OF ANY THICKER FOG THIS MORNING. ANY BREAKS COULD BRING BRIEF IFR IN WV MOUNTAIN VALLEYS SUCH AS EKN. CONVECTION DROPPING SE THROUGH WRN KY TOWARD TN BUT A FEW SHOWERS MAY FORM FURTHER E AND AFFECT SW VA THIS MORNING. WILL HAVE MOSTLY 3 TO 5 THSD FT SCT TO BKN AGL TODAY WITH LAYERS ABOVE. COULD NOT TIME ANY DEFINITE ROUNDS OF CONVECTION THIS AFTERNOON SO HAVE VCNTY THUNDERSTORM IN MOST TAF SITES. TRIED TO INCREASE COVERAGE IN SE OHIO AFTER 20Z...THEN MOVE INTO WV FOR 00Z TO 06Z. CEILINGS LOWER NEAR FRONT TO 2 TO 3 THSD FT BKN TO OVC AND VSBY NEAR 3 MILES IN ANY SHOWER/STORM. WITH WEAK LOW PRESSURE DEVELOPING IN UPPER OHIO VALLEY TODAY...HAVE ITS ASSOCIATED FRONT/WIND SHIFT REACHING INTO OUR SE OHIO BY 06Z TUESDAY. CEILINGS DETERIORATING FURTHER BUT MOSTLY AFTER 06Z TUESDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: SPECIFIC TIMING OF ROUNDS OF CONVECTION THIS AFTERNOON AND OVERNIGHT TONIGHT WILL VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE MON 08/10/15 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 CRW CONSISTENCY H H M M H H H H H H H H HTS CONSISTENCY H H M M H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY M M L L L M M H H H H H PKB CONSISTENCY H H M M H H H H H H H H CKB CONSISTENCY H H M M M H H H H H H H AFTER 06Z TUESDAY... NEAR AND IN WAKE OF FRONT...LINGERING LOW CEILINGS AND SHOWERS THROUGH TUESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...30 AVIATION...KTB
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
351 AM EDT MON AUG 10 2015 .SYNOPSIS... RETURN FLOW OFF THE GULF OF MEXICO WILL BRING IN MOISTURE TODAY AHEAD OF THE NEXT COLD FRONT. EXPECT SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT UNTIL THIS FRONT PASSES LATE TUESDAY. COOLER AND DRIER HIGH PRESSURE WILL BE IN CONTROL OF OUR WEATHER FROM WEDNESDAY INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... SOME LINGERING -SHRA/TSTMS ACROSS THE NC PIEDMONT AND EXTREME SRN ZONES THIS MORNING. THIS ACTIVITY IS REMAINING FAIRLY STATIONARY ALONG THE EDGE OF A ERN SFC HIGH WITH MOIST W/LY LIFT. SOME ADDITIONAL CELLS COULD FILL IN THROUGH DAYBREAK...BUT OVERALL THE ACTIVITY WILL REMAIN SHALLOW WITH ECHO TOPS AROUND 20 KFT. ENUF CELL MOVEMENT IS EVIDENT TO HAVE MUCH OF A HYDRO CONCERN...BUT WILL MONITOR FOR ANY POSSIBLE ISSUES. THE FCST FOR THIS AFTERNOON IS A LITTLE TRICKY AS CLOUD COVER ACROSS THE ERN ZONES SHOULD INHIBIT DEEP INSTABILITY UNTIL LATE DAY. PLAN VIEW SBCAPE SHOWS THE BEST POTENTIAL ACROSS THE UPPER SAVANNAH VALLEY AND NORTH ACROSS THE BLUE RIDGE AND MOST OF THE UPSTATE. THERE IS NOT A LOT OF DYNAMIC FORCING TO BE HAD. THE H3 FLOW DOES BECOME DIFFLUENT AND THIS WILL HELP BRING IN A PRE/FRONTAL TROF...BUT NO WELL DEFINED NOR ACUTE S/W ENERGY SHOULD BE AVAILABLE. EXCEPT PERHAPS ACROSS NE GA AND THE FAR WRN UPSTATE PER SOME HIRES MOD SOLNS. SO...EXPECT ISOL TSTM ACTIVITY TO BEGIN ACROSS THE MTNS AND ARND 17Z OR SO...THEN SLOWLY FILL IN TO THE EAST THROUGHOUT THE AFTERNOON/EVENING. POPS HAVE BEEN BUMPED DOWN ACROSS THE NC PIEDMONT AND SE/RN UPSTATE DUE TO UNCERTAINTY WITH INSTABILITY AND PROGRESSION OF THE PF/TROF. THE STRONGER STORMS WILL DEVELOP ACROSS NE GA ALONG THE SC BORDER AND THE SRN BLUE RIDGE. BULK SHEAR IS NOT THAT IMPRESSIVE...ON THE ORDER OF 20 KTS...BUT AREAS OF GOOD DIFF HEATING COULD SUPPORT ISOL SEVERE CONVECTION. THE BETTER ULVL ENERGY AND A S/W TROF MOVES INTO THE NC MTNS AFT 00Z WHICH WILL THEN CROSS THE FA THROUGH THE OVERNIGHT. CROSS SECTIONS DEPICT AROUND 150 J/KG OF ELCAPE...SO THUNDER MENTION WILL REMAIN ALL ZONES WHILE POPS DROP TO THE LOWER CHANCE RANGE BY DAYBREAK. THE UPPER PATTERN BECOMES MORE CYCLONIC AND DIFFLUENT OVERNIGHT AS WELL...SO STRONG AND HIGH RAINFALL RATE STORMS ARE POSSIBLE. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 315 AM MON...SFC COLD FRONT IS PROGGED TO PUSH THRU THE AREA TUE ENHANCING FORCING IN AN OTHERWISE FAVORABLE ENVIRONMENT FOR DEEP CONVECTION. FRONTAL TROUGH AXIS WILL CROSS THE MTNS IN THE MRNG AND MODEST COVERAGE OF SHRA/TSRA IS EXPECTED THEN. DESTABILIZATION WILL OCCUR PRIOR TO THE FRONT ITSELF. HIGHER RES GUIDANCE SUGGESTS THE MRNG ACTIVITY WILL DISSIPATE AND/OR PROPAGATE OUT OF THE AREA BEFORE A SECOND ROUND DEVELOPS OVER THE MTNS WITH THE FRONT. THE PIEDMONT ACTIVITY...PARTICULAR THAT BEGINNING EARLIER IN THE DAY...POSES A HEAVY RAIN THREAT DUE TO PWAT VALUES AT OR ABOVE THE 90TH PERCENTILE...BUT AS DRIER AIR WORKS IN ALOFT BEHIND THE TROUGH PWATS DIP BACK TO VALUES NEAR CLIMATOLOGICAL MEDIAN. STORMS SHOULD MOVE PRETTY QUICKLY GIVEN THE BRISK FLOW ALOFT...AND NO WELL-DEFINED LLJ IS SEEN ON PROFILES. SO ANY HYDRO CONCERNS APPEAR LIKELY TO REMAIN LOCALIZED ESPECIALLY IN LIGHT OF DRY SOIL CONDITIONS OVERALL. INSTABILITY IS NOT THE GREATEST BUT SHEAR IS APPRECIABLE. 0-6KM BULK VALUES PEAK AT 30-35 KT WHICH WILL ALLOW AT LEAST LOOSE ORGANIZATION. SO AT THE OTHER END OF THE SPECTRUM...AS DRYING OCCURS ALOFT THE LATER ROUND OF STORMS WILL BE CAPABLE OF DAMAGING WINDS ON A SOMEWHAT LARGER SCALE THAN WE OFTEN SEE THIS TIME OF YEAR. SPC DAY 2 OUTLOOK PAINTS OUR PIEDMONT IN A MARGINAL RISK AREA BUT THERE APPEARS TO BE SOME RISK THROUGHOUT THE AREA...UNLESS THE FRONT ARRIVES EARLIER THAN ANTICIPATED. THE FRONT BRINGS DRIER AND COOLER AIR ACRS THE AREA TUE NIGHT AS POPS DROP TO UNMENTIONABLY LOW VALUES. DIURNAL CONVECTION IS NOT EXPECTED WED AND DEWPOINTS WILL BE COMFORTABLY LOW FOR MID-AUGUST. MINS THU MORNING WILL BE SLIGHTLY BELOW CLIMO ALSO. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 200 AM TUE...HIGHLY AMPLIFIED UPPER PATTERN FEATURING SHARP ERN TROUGH AND WRN RIDGE EXPECTED THU...BEGINNING TO BREAK DOWN BY LATE FRI AS THE TROUGH LIFTS AND RIDGE BEGINS TO SHEAR. AT THE SFC THIS MEANS BROAD SFC HIGH PRESSURE SPREADS EAST. A PORTION OF THE RETREATING TROUGH SHEARS OFF OVER THE CENTRAL GULF COAST SATURDAY POSSIBLY LEADING TO THE DEVELOPMENT OF A SFC LOW ALONG STALLED FRONT. THESE FEATURES INITIATE MOIST RETURN FLOW FRI WHICH MAY CONTINUE INTO THE WEEKEND PER GFS SOLUTION. THIS WOULD PROBABLY ALLOW SOME DIURNAL CONVECTION TO RESUME AT LEAST OVER THE BLUE RIDGE. THE 09/12Z EC AND TO SOME EXTENT THE 10/00Z GEM DEPICT A SECOND SFC HIGH MOVING THRU THE OHIO VALLEY WHICH LEADS IT TO KEEP A DRIER AND MORE NORTHERLY FLOW INTO OUR AREA. MAINLY SCHC POPS ARE MENTIONED EACH DAY OF THE PERIOD...AND MAINLY NEAR THE BLUE RIDGE. TEMPS WILL START OFF A FEW DEGREES BELOW CLIMO IN THE CONTINENTAL AIRMASS...MODERATING TO NEAR CLIMO BY SUNDAY NIGHT AS IT MODIFIES. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... AT KCLT...CONTINUED IDEA OF PREVIOUS TAF WITH BRINGING IN LOW SCT STCU BEFORE SUNRISE. NOT ENUF MOISTURE RESPONSE ON RAP SOUNDINGS TO GO FOR A CIG ATTM. STILL EXPECT TSTMS THIS AFTERNOON...BUT MAY HAVE TO PUSH BACK TIMING ON THE 12Z TAF. MODEL PROGRESSION OF MUCAPE IS IS SLOW TO MOVE EAST AS LLVL CLOUD COVER COULD PERSIST THROUGH NOON OR SO. IN FACT THE PREFRONTAL DEEP CONVECTION MAY REMAIN WEST OF THE TERMINAL UNTIL LATE IN THE PERIOD. ELSEWHERE...SOME MVFR/IFR IS POSSIBLE AT KAVL AND KHKY THIS MORNING AS TTD/S ARE RUNNING 1-2 F. POSSIBLE VSBY CONCERNS ACROSS THE SC SITES AS WELL ARND DAYBREAK. CONVECTIVE ACTIVITY WILL AFFECT KAVL ARND 18Z AS PREFRONTAL TROF DEVELOPS AND FORCING SPREADS EAST INDUCING THUNDER AT THE OTHER TERMINALS 1-3 HRS LATER. PRECIP AND THUNDER WILL PERSIST NEAR ALL TERMINALS LATE IN THE TAF PERIOD WITH SOME VSBY/CIGS ISSUES PROBABLE. OUTLOOK...HEAVY RAINFALL MON AFTN/EVENING ASSOCIATED WITH THE COLD FRONT/SHORTWAVE COULD LEAD TO SOME MORNING RESTRICTIONS TUE. DRIER/VFR CONDITIONS RETURN BY TUE EVENING...AND SHOULD PREVAIL THRU AT LEAST THURSDAY. CONFIDENCE TABLE... 08-14Z 14-20Z 20-02Z 02-06Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 83% HIGH 89% HIGH 100% HIGH 93% KAVL HIGH 84% HIGH 88% HIGH 96% HIGH 83% KHKY HIGH 86% HIGH 82% HIGH 100% HIGH 97% KGMU HIGH 91% MED 76% HIGH 90% HIGH 93% KAND HIGH 87% HIGH 93% HIGH 100% HIGH 93% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...WIMBERLEY NEAR TERM...SBK SHORT TERM...WIMBERLEY LONG TERM...WIMBERLEY AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
134 AM EDT MON AUG 10 2015 .SYNOPSIS... A SOUTH TO SOUTHWEST WIND FLOW WILL DEVELOP TONIGHT AND CONTINUE INTO MONDAY BRINGING IN MOISTURE OFF THE GULF AHEAD OF THE NEXT COLD FRONT. EXPECT SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT UNTIL THIS FRONT PASSES LATE TUESDAY. COOLER AND DRIER HIGH PRESSURE WILL BE IN CONTROL OF OUR WEATHER FOR THE LAST HALF OF THE WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 130 AM EDT MONDAY...NO SIGFNT CHANGES NEEDED TO THE GOING FCST. CLOUD COVER WAS UPDATED TO ACCOUNT FOR THICK CI ADV ACROSS THE NRN ZONES. MADE SOME MINOR TWEAKS TO T/TD GRIDS ACROSS THE UPSTATE. AS OF 1030 PM EDT SUNDAY...ONLY ISOLATED CONVECTION STILL OUT THERE THIS EVENING BUT RAPIDLY DISSIPATING. MOST GRIDS LOOK GOOD WITH ONLY MINOR CHANGES BASED ON OBSERVATIONAL TRENDS. AS OF 730 PM EDT SUNDAY...VERY FEW ADDITIONAL CHANGES TO THE GRIDS THIS EVENING WITH JUST MINOR TWEAKS TO POPS/SKY/TEMPS/DEWPOINTS. CONVECTION IS BEGINNING TO WANE AS EXPECTED THOUGH THERE IS STILL SOME ENHANCED CU AT THE HIGHER ELEVATIONS...BUT THE TREND IS DEFINITELY DOWN. STILL MONITORING OVERNIGHT FOG POTENTIAL WHICH WILL BE HEAVILY DEPENDENT ON HOW THE GROUND RESPONDS TO THE RAINFALL THIS EVENING. OVERALL NO SIGNIFICANT CHANGES AT THIS TIME. AS OF 430 PM EDT SUNDAY...HAVE INCREASED POPS ACROSS MAINLY THE UPSTATE TO ACCOUNT FOR INCREASING SHOWER ACTIVITY. ONLY ISOLATED LIGHTNING STRIKES HERE AND THERE SO KEPT THUNDER WORDING AT CHANCE WITH LIKELY SHOWERS. VERY EFFICIENT RAINFALL PRODUCERS WITH ONE REPORT OF 2 INCHES IN 45 MINUTES IN TRANSYLVANIA COUNTY. WILL CONTINUE TO MONITOR AND ADJUST POPS ACCORDINGLY AS NECESSARY. MADE SIMILAR ADJUSTMENTS TO SKY COVER FOR THE NEXT FEW HOURS...AND SOME MINOR TWEAKS TO HOURLY TEMPS/WINDS/DEWPOINTS BASED ON OBS. AS OF 230 PM EDT SUNDAY...CU FIELD IS BUBBLING INTO ISOLATED SHOWERS ACROSS ROUGHLY THE SW HALF OF THE FORECAST AREA. WITH CAPE GENERALLY LIMITED TO THE 1000-1500 J/KG RANGE ACROSS THIS AREA...IT/S DEBATABLE AS TO WHETHER ANY UPDRAFTS WILL BECOME STRONG ENOUGH TO PRODUCE LIGHTNING...BUT WILL CONTINUE A MENTION OF ISOLATED/WIDELY SCT SHOWERS AND STORMS ACROSS THE WESTERN 2/3 OF THE FORECAST AREA THROUGH THE AFTERNOON. ANY LINGERING CONVECTION SHOULD DISSIPATE RATHER QUICKLY AFTER SUNSET...GIVING WAY TO A TYPICALLY WARM/MUGGY NIGHT...WITH MIN TEMPS EXPECTED TO AVERAGE A COUPLE OF DEGREES ABOVE CLIMO...POSSIBLY EVEN WARMER DEPENDING UPON IF/HOW SOON LOW CLOUDS EXPAND ACROSS THE FORECAST AREA WITHIN INCREASING SOUTHERLY FLOW REGIME. SUBSTANTIVE UPPER HEIGHT FALLS WILL OVERSPREAD THE EASTERN CONUS BY THE END OF THE NEAR TERM PERIOD...ALLOWING FOR RETROGRESSION OF THE LONG WAVE PATTERN. HIGHER RESOLUTION SHORT TERM MODELS ARE IN GOOD AGREEMENT IN DROPPING A SHORT WAVE TROUGH INTO WESTERN NC BY MONDAY AFTERNOON...ACCOMPANIED BY INCREASING DEEP LAYER MOISTURE. IMPROVING MID-LEVEL LAPSE RATES RESPONDING TO RIDGE RETROGRESSION SHOULD RESULT IN IMPROVED...BUT STILL SOMEWHAT MODEST INSTABILITY PROFILES. CONSIDERING THESE INGREDIENTS...COVERAGE OF CONVECTION SHOULD BE QUITE RESPECTABLE MONDAY AFTERNOON...AND ANYWHERE FROM 50-70 POPS WILL BE ADVERTISED...GENERALLY ALONG/NORTH OF I-85...TAPERING TO 30-40 PERCENT SOUTH OF THERE. DESPITE INCREASING SHEAR PROFILES DEVELOP AS A CONSEQUENCE OF ANOMALOUSLY STRONG HEIGHT FALLS...THE SEVERE CONVECTIVE THREAT APPEARS MARGINAL AT BEST MON PM...OWING TO THE EXPECTED ABSENCE OF ROBUST INSTABILITY. STILL CAN/T RULE OUT SOME ISOLATED SEVERE STORMS...ESP IF THE SHEAR PROVES STRONG ENOUGH TO ORGANIZE SMALL CONVECTIVE CLUSTERS. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... AS OF 230 PM SUNDAY...A LARGE UPPER TROF WILL DIG ACRS THE GREAT LAKES AND OHIO VALLEY MONDAY NIGHT THRU TUESDAY...SHARPENING THE TROF AXIS ALONG THE APPALACHIANS BY WEDNESDAY. THIS WILL COINCIDE WITH A COLD FROPA ON TUESDAY...WHICH SHUD HAVE DECENT QG FORCING AND MOISTURE FOR GOOD CONVECTIVE COVERAGE. MOISTURE AND UPGLIDE AHEAD OF THE FRONT WILL KEEP A CHC POP THRU THE OVERNIGHT MONDAY NIGHT. THEN ON TUESDAY...THE MODELS ARE IN DECENT AGREEMENT ON THE FRONT CROSSING THE CWFA TUESDAY EVENING. THERE SHUD STILL BE PLENTY OF INSTBY FOR AT LEAST A SOLID CHC POP ALONG AND EAST OF THE BLUE RIDGE. SBCAPE WILL RANGE FROM 1500-2500 J/KG PER THE GFS/NAM BLEND. THE 0-6 KM BULK SHEAR WILL BE AROUND 25-30 KTS. SO EXPECT SOME ORGANIZATION POTENTIAL WITH CONVECTION TUESDAY AFTN/EVE. THE DAY 3 CONVECTIVE OUTLOOK HAS A MARGINAL RISK ROUGHLY ALONG I-85 AND EAST. TEMPS WILL BE A CATEGORY OR TWO ABOVE NORMAL MONDAY NIGHT AND TUESDAY...THEN AT OR SLIGHTLY BELOW NORMAL TUESDAY NIGHT AND WEDNESDAY DRIER AIR AND COOLER THICKNESSES COME IN BEHIND THE FRONT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 145 PM SUNDAY...STARTING AT 00Z THURSDAY...THE 500MB PATTERN SHOWS A TROUGH OVER THE EAST WITH AXIS ALONG THE APPALACHIANS AND A RIDGE OVER THE ROCKIES. GOING INTO FRIDAY AND SATURDAY...THE SOUTHERN PART OF THE EASTERN TROUGH IS EXPECTED SHEAR OFF GRADUALLY INTO A CUT OFF UPPER LOW WHICH SHOULD BE FORMED BY SATURDAY NIGHT OVER THE MISS DELTA. THIS CUT OFF LOW IS EXPECTED TO DRIFT WEST TO THE TEXAS COAST BY SUNDAY NIGHT WHICH IS THE END OF THE CURRENT FORECAST PERIOD. AT THE SURFACE FOR WED NIGHT...DRY HIGH PRESSURE CENTERED NEAR CHICAGO AND A STALLED OUT FRONT FROM THE GULF COAST TO NRN FLORIDA THEN OUT OVER THE ATLANTIC OFF THE CAROLINA COAST. THE FRONT IS CLOSE ENOUGH THROUGH THE EARLY WEEKEND THAT IF A STRONG WAVE OF LOW PRESSURE WERE TO PASS ALONG IT...THE RESULT MAY BE A FEW SHOWERS FOR OUR SE ZONES MAINLY OVER THE PIEDMONT OR OVER THE FAR SOUTHERN MTNS. CURRENT LOW LEVEL WIND FORECAST HAS A NORTHERLY WIND WED NIGHT...PERHAPS AN UPSLOPE WIND FROM THE EAST TO SE THURSDAY AND THURSDAY NIGHT...THEN LIGHT AND VARIABLE THROUGH SUNDAY NIGHT. ON SUNDAY...THE FRONT IS FORECAST TO DRIFT MORE SOUTH OVER FLORIDA AND DRIER AIR OVER OUR AREA WITH HIGH PRESSURE. ALTHOUGH CAPES ARE FORECAST TO BE AROUND 2000 OR ABOVE FOR THE NC MTNS LATE SAT AND SUN...THERE IS VERY LITTLE MOISTURE. TEMPS A FEW DEGREES BELOW NORMAL THURSDAY THEN SLOWLY RECOVERING TO AROUND NORMAL SUNDAY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AT KCLT...CONTINUED IDEA OF PREVIOUS TAF WITH BRINGING IN LOW SCT STCU BEFORE SUNRISE. NOT ENUF MOISTURE RESPONSE ON RAP SOUNDINGS TO GO FOR A CIG ATTM. STILL EXPECT TSTMS THIS AFTERNOON...BUT MAY HAVE TO PUSH BACK TIMING ON THE 12Z TAF. MODEL PROGRESSION OF MUCAPE IS IS SLOW TO MOVE EAST AS LLVL CLOUD COVER COULD PERSIST THROUGH NOON OR SO. IN FACT THE PREFRONTAL DEEP CONVECTION MAY REMAIN WEST OF THE TERMINAL UNTIL LATE IN THE PERIOD. ELSEWHERE...SOME MVFR/IFR IS POSSIBLE AT KAVL AND KHKY THIS MORNING AS TTD/S ARE RUNNING 1-2 F. POSSIBLE VSBY CONCERNS ACROSS THE SC SITES AS WELL ARND DAYBREAK. CONVECTIVE ACTIVITY WILL AFFECT KAVL ARND 18Z AS PREFRONTAL TROF DEVELOPS AND FORCING SPREADS EAST INDUCING THUNDER AT THE OTHER TERMINALS 1-3 HRS LATER. PRECIP AND THUNDER WILL PERSIST NEAR ALL TERMINALS LATE IN THE TAF PERIOD WITH SOME VSBY/CIGS ISSUES PROBABLE. OUTLOOK...HEAVY RAINFALL MON AFTN/EVENING ASSOCIATED WITH THE COLD FRONT/SHORTWAVE COULD LEAD TO SOME MORNING RESTRICTIONS TUE. DRIER/VFR CONDITIONS RETURN BY TUE EVENING...AND SHOULD PREVAIL THRU AT LEAST THURSDAY. CONFIDENCE TABLE... 05-11Z 11-17Z 17-23Z 23-00Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 95% HIGH 90% HIGH 100% KAVL HIGH 100% MED 78% HIGH 100% HIGH 93% KHKY HIGH 100% HIGH 90% HIGH 85% HIGH 100% KGMU HIGH 100% MED 68% MED 70% HIGH 100% KAND HIGH 100% HIGH 95% HIGH 95% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...SBK/TDP SHORT TERM...ARK LONG TERM...DEO AVIATION...SBK
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
439 AM CDT MON AUG 10 2015 .DISCUSSION... A COMPLEX WEATHER DAY ACROSS THE MIDSOUTH. THE UPPER LEVEL RIDGE THAT BROUGHT TRIPLE DIGIT HEAT CLOSE TO THE MIDSOUTH YESTERDAY HAD RETROGRADED OVER THE PAST 12 HOURS...RETURNING NORTHWEST FLOW ALOFT TO THE MIDSOUTH. SEVERAL THUNDERSTORM COMPLEXES HAD FORMED OVER SOUTHERN MO EARLY THIS MORNING...MOVING SOUTHEAST ALONG THE UPPER RIDGE PERIPHERY. ASSUMING THE COLD POOL CAN REMAIN ESTABLISHED THROUGH SUNRISE... 850-500MB THICKNESS FIELDS SUGGEST THESE STORMS WILL MOVE SOUTH/SOUTHEAST THROUGH NORTHEAST AR...WEST TN AND NORTHEAST MS. THE HRRR MODEL HAS BEEN CONSISTENT IN DEPICTING SUCH A SCENARIO. THE AIRMASS FEEDING THESE STORMS WAS RICH WITH MOISTURE...WITH PRECIPITABLE WATER VALUES AROUND 2.25 INCHES. THE LOW LEVEL JET HAS BEEN A RELATIVELY WEAK 20KTS...BUT ADEQUATE TO MAINTAIN STORMS EARLY THIS MORNING. THUNDERSTORM EVOLUTION THROUGH MIDDAY WILL HAVE SIGNIFICANT IMPACTS ON AFTERNOON HEAT INDICES. HAVE TRIMMED BACK HEAT HEADLINES TO REFLECT THE IMPACTS OF THUNDERSTORM OUTFLOW AND INITIAL CLOUD COVER. HEAT INDEX FORECAST CONFIDENCE IS MARGINAL... BUT PERHAPS BEST OVER THE MS RIVER DELTA...FROM CLARKSDALE TO CHARLESTON MS. THIS AREA WILL LEAST LIKELY BE IMPACTED BY THUNDERSTORM OUTFLOW AND CLOUD COVER...AND NEAREST TO THE AFTERNOON LOW LEVEL THERMAL RIDGE OVER SOUTHERN AR AND CENTRAL MS. A WEAK COLD FRONTAL PASSAGE APPEARS ON TRACK FOR LATE THIS EVENING AND EARLY OVERNIGHT. COOLER AND DRIER AIR WILL LAG 12 TO 18 HOURS BEHIND THE INITIAL WIND SHIFT...BUT LIKELY SUFFICIENT TO KEEP TUESDAY AFTERNOON HEAT INDICES BELOW ADVISORY CRITERIA. WEDNESDAY AND THURSDAY SHOULD SEE COOLER AND DRIER CONDITIONS...WITH NORTHERLY WINDS. DAYTIME TEMPS WILL GRADUALLY MODERATE TO NEAR NORMAL VALUES FROM FRIDAY THROUGH NEXT MONDAY...AS THE UPPER RIDGE BUILDS INTO THE MIDDLE MS RIVER VALLEY. RAIN CHANCES FROM MIDWEEK THROUGH EARLY NEXT WEEK APPEAR MINIMAL. PWB && .AVIATION... 06Z TAF CYCLE A MESOSCALE CONVECTIVE SYSTEM IS BACK BUILDING ACROSS SOUTHEASTERN MO AND SOUTHERN IL. THIS SYSTEM IS EXPECTED TO GENERATE A SOUTHWARD MOVING OUTFLOW BOUNDARY THAT WILL RESULT IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS AFFECTING KMKL AND KJBR AFTER 10/08Z...KMEM AFTER 10/11Z AND CONTINUE THROUGH MUCH OF THE MORNING. CONDITIONS MAY LOWER TO MVFR OR IFR IN THE HEAVIER THUNDERSTORMS ESPECIALLY AT KMKL AND KJBR. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG AND AHEAD OF A COLD FRONT APPROACHING AND MOVING INTO THE AREA FROM THE NORTH BEGINNING MONDAY AFTERNOON. VFR CONDITIONS WILL OCCUR MUCH OF THE PERIOD AT THE TAF SITES OUTSIDE ANY SHOWERS AND THUNDERSTORMS. LIGHT WINDS TONIGHT BECOMING WESTERLY MONDAY 6-8 KTS. WINDS MAY BE STRONG AND GUSTY NEAR THUNDERSTORMS. AFTER 11/00Z...THE COLD FRONT WILL CONTINUE SOUTHWARD THOUGH THE REGION. WINDS TURNING TO THE NE AT 4-7 KTS WITH THE THREAT OF SHOWERS AND THUNDERSTORM ENDING FOLLOWING THE FRONT. JCL && .MEG WATCHES/WARNINGS/ADVISORIES... AR...EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR PHILLIPS. HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR CRITTENDEN-CROSS-LEE AR-POINSETT-ST. FRANCIS. MO...NONE. MS...EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR CALHOUN-COAHOMA-QUITMAN-TALLAHATCHIE-YALOBUSHA. HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR BENTON MS-CHICKASAW-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS- MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-TATE-TIPPAH-TUNICA- UNION. TN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR FAYETTE-SHELBY. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1228 AM CDT MON AUG 10 2015 .AVIATION.../06Z TAFS/ NO CONCERNS WITH HIGH PRESSURE REMAINING IN CONTROL AT THE SURFACE AND ALOFT. SATELLITE CURRENTLY SHOWING LOW CLOUD DEVELOPMENT OVER THE COASTAL PLAINS. EXPECT TO SEE KSAT/KSSF BECOME MVFR 07Z-08Z. NOT AS CONFIDENT FOR KAUS AND WILL CONTINUE WITH A TEMPO FOR MVFR CIGS THERE. KDRT WILL ONLY SEE AN HOUR OR TWO OD SCT SO NO ISSUES. S/SE WINDS WILL DECREASE TO NEAR 10 KNOTS AFTER 06Z. SOUTHERLY WINDS INCREASE TO 10-15 KNOTS WITH GUSTS TO NEAR 20 KNOTS AFTER 15Z AND BECOME SELY SAME SPEEDS AFTER 21Z. LIKELY TO SEE LESS LOW CLOUD DEVELOPMENT FOR MON NIGHT INTO TUES MORNING SO NO ISSUES FOR THE 30 HOUR TAF SITES. && .PREV DISCUSSION... /ISSUED 852 PM CDT SUN AUG 9 2015/ UPDATE... /NPW CANCELED/ ALL HEAT INDEX REPORTS IN THE AREA FELL BELOW 105 AND WELL BELOW THE ADVISORY CRITERIA OF 108/110 DEGREES FOR EAST/WEST COUNTIES. A SPECIAL WEATHER STATEMENT FOR THE NEXT COUPLE DAYS REPLACES THE CANCELED HEAT ADVISORY. PREV DISCUSSION... /ISSUED 637 PM CDT SUN AUG 9 2015/ AVIATION.../00Z TAF CYCLE/ VFR SKC ACROSS MUCH OF THE REGION WITH ONLY A FEW/SCT250 CIRRUS CLOUDS AS OF 09/2330Z. VFR WILL CONTINUE UNTIL 09Z OR SO WITH DEVELOPMENT OF MVFR STRATUS CLOUDS INVOF KSAT/KSSF AND KAUS THROUGH 14-15Z. HIGHEST CONFIDENCE EXISTS FOR SAT/SSF PER SOUNDING ANALYSIS AND HRRR OUTPUT. KAUS COULD ALSO BE IMPACTED WITH BKN015 CIGS BUT MAY BE MORE SPORADIC. KDRT SHOULD STAY VFR THROUGH THE NIGHT BUT STRATUS WAS CLOSE BY THIS MORNING AND THIS TREND WILL NEED TO MONITORED IN THE 06Z TAF ISSUANCE. CURRENT SURFACE WINDS OF 10-15 KT OUT OF THE SE WILL CALM TO 5-10KT OVERNIGHT. VFR CONDITIONS WILL PREVAIL MONDAY AFTER 15Z WITH A REPEAT OF TODAY. PREV DISCUSSION... /ISSUED 240 PM CDT SUN AUG 9 2015/ SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)... HIGH PRESSURE RIDGE CONTINUES TO DOMINATE THIS AFTERNOON. CURRENT HEAT ADVISORY WILL EXPIRE THIS EVENING. PEAK HEATING HAS YET TO OCCUR BUT LOOKS LIKE A FEW SPOTS WILL HIT ADVISORY CRITERIA MAINLY OVER THE FAR EAST...DECENT MIXING ACROSS THE REST OF THE AREA WILL DROP DEW POINTS THROUGH THE DAY. MILD NIGHT TONIGHT WITH A REPEAT OF STRATUS FORMATION ACROSS CENTRAL SECTIONS WITH STRONGER LOW LEVEL SOUTHERLY FLOW. ANOTHER HOT DAY ON MONDAY BUT THE UPPER RIDGE WILL START A WESTWARD MOVEMENT THAT WILL BRING SLIGHT ADJUSTMENTS TO POP AND TEMPS LATER IN THE WEEK. FAIRLY LOW DEWPOINTS WILL GENERALLY KEEP AREA HEAT INDEX VALUES JUST BELOW HEAT ADVISORY CRITERIA LEVELS. A WEAK FRONT WILL PUSH SOUTH INTO THE RED RIVER AREA...HELPING TO DECREASE THE GRADIENT MONDAY NIGHT AND LIMIT THE EARLY MORNING CLOUD COVER BY TUESDAY. LONG TERM (TUESDAY THROUGH SUNDAY)... AS THE UPPER RIDGE SHIFTS WEST BY MID WEEK...A SIMILAR PATTERN WILL DEVELOP LIKE THE END OF JULY. A WEAK BACKDOOR COOL FRONT WILL PUSH INTO EAST AND NE TEXAS AS MID AND UPPER FLOW BECOMES INCREASINGLY EASTERLY/NORTHEASTERLY. RH TIME SECTIONS SHOWS AN INCREASE IN MID LEVEL MOISTURE STARTING LATE TUE INTO WED. THIS MOISTURE INCREASE...ALONG WITH THE EXPECTED HOT TEMPS...SHOULD BE ENOUGH TO FIRE UP ISOLATED/SCT CONVECTION DURING THE AFTERNOON/EVENING HOURS ON WED AND AGAIN ON THU. LIKE THE PREVIOUS SYSTEM ABOUT 10 DAYS AGO...STORMS COULD PRODUCE SOME STRONG DOWNDRAFTS...WITH SEVERAL OUTFLOW BOUNDARIES LIKELY HELPING TO INITIATE ADDITIONAL STORMS. THIS MID LEVEL MOISTURE WILL PUSH WEST THROUGH THE WEEK...AND BY WEEKS END...POP WILL BE CONFINED TO THE FAR WEST AND NORTHWEST. BY THE WEEKEND AND EARLY NEXT WEEK...LONG RANGE MODELS ARE SHOWING AN UPPER LOW OVER THE SE U.S. MOVING WEST ALONG THE NORTHERN GULF COAST...MOVING TOWARD THE TEXAS COAST. LOWERING 500MB HEIGHTS AND BETTER MOISTURE LEVELS WILL KEEP THE INTENSE HEAT AWAY...BUT THE HIGHER DEWPOINTS MIGHT ACTUALLY KEEP HEAT INDEX VALUES PLENTY WARM. CANT RULE OUT SOME CHANCES OF RAIN ESPECIALLY IN THE COASTAL PLAINS DUE TO THE PROXIMITY OF THE UPPER LOW. THE HOPE WILL BE FOR THIS SYSTEM AND MOISTURE TO PUSH FARTHER INLAND AND GIVE SOME RAIN CHANCES BEYOND THE 7 DAY PERIOD. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 76 102 78 101 77 / 0 0 0 - 10 AUSTIN BERGSTROM INTL AIRPORT 74 101 74 101 76 / 0 0 0 - 10 NEW BRAUNFELS MUNI AIRPORT 77 102 76 101 76 / 0 0 0 0 - BURNET MUNI AIRPORT 73 101 76 101 78 / 0 0 0 - 10 DEL RIO INTL AIRPORT 77 102 77 103 78 / 0 0 0 0 0 GEORGETOWN MUNI AIRPORT 75 102 77 102 79 / 0 0 0 - 10 HONDO MUNI AIRPORT 74 101 74 102 75 / 0 0 0 0 0 SAN MARCOS MUNI AIRPORT 76 100 75 101 77 / 0 0 0 - - LA GRANGE - FAYETTE REGIONAL 75 101 77 103 77 / 0 0 0 10 10 SAN ANTONIO INTL AIRPORT 78 101 77 101 78 / 0 0 0 0 - STINSON MUNI AIRPORT 77 102 76 101 77 / 0 0 0 0 - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...10 SYNOPTIC/GRIDS...04
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
314 AM EDT MON AUG 10 2015 .SYNOPSIS... A WARM FRONT WILL LIFT SLOWLY NORTHEAST INTO THE REGION TODAY BEFORE SLIDING TO THE NORTH LATER TONIGHT. A STRONG COLD FRONT WILL PUSH EAST INTO THE MOUNTAINS BY EARLY TUESDAY AND ACROSS THE REMAINDER OF THE REGION BY TUESDAY EVENING. HIGH PRESSURE BUILDS INTO THE AREA BEHIND THE FRONT BY WEDNESDAY...BRINGING SOMEWHAT COOLER AND DRIER AIR FOR MIDWEEK INTO THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 220 AM EDT MONDAY... CLUSTERS OF VERY SLOW MOVING SHOWERS CONTINUE TO DEVELOP EARLY THIS MORNING ESPCLY OVER THE EAST IN ADVANCE OF A RATHER STRONG MID LEVEL WAVE DIPPING IN FROM THE NW JUST NORTH OF THE FRONT TO THE SW. THIS UNDERDONE BY MOST SHORT TERM MODELS INCLUDING THE HRRR SO BUMPING UP POPS TO AT LEAST CHANCE IN PARTS OF THE EAST AND SLIGHTS OVER THE WEST WHERE SHRA MORE SPOTTY NATURE CLOSER TO THE ACTUAL IMPULSE ALOFT. ONCE THIS FEATURE PASSES...LOTS OF UNCERTAINTY IN REGARDS TO THE CONVECTIVE ENVIRONMENT FROM LATE MORNING INTO THE AFTERNOON WITH A WARM FRONT HEADING INTO THE MOUNTAINS WHILE CLOUD COVER MAY STAY RATHER EXTENSIVE. GUIDANCE SOLUTIONS RANGE FROM THE BEST LIFT STAYING WEST OF THE MOUNTAINS UNTIL THIS EVENING SUPPORTING ONLY SCATTERED SHRA/TSRA BLUE RIDGE LATER...TO MORE OUTFLOW DRIVEN SUPPORT FROM THE MCS TO THE WEST WITH THIS RESIDUAL WAVE INTERACTING WITH AT LEAST SOME HEATING TO PRODUCE MORE MULTICELLULAR BANDS/CLUSTERS SIMILAR TO THE GFS/EC AND NCAR ENSEMBLE. THIS ALONG THE LINGERING HIGHER 85H THETA-E RIDGE WEST AND WHERE MODELS SUGGEST AT LEAST SOME DECENT CAPE MAY EXIST BUT LATER. THUS TRENDED MORE ALONG THOSE LINES AND BUMPED GOING POPS TO A PERIOD OF CATEGORICAL FAR WEST LATE AND LEFT LIKELYS IN ALL EXCEPT THE SE WHERE MAY BE LATE OR THIS EVENING BEFORE WHATS LEFT OF WESTERN COVERAGE MOVES EAST GIVEN WEAK STEERING. THIS COULD ALSO LEAD TO MORE OF A HEAVY RAINFALL THREAT VS SEVERE GIVEN RATHER MEAGER FLOW ALOFT AND LACK OF GOOD LAPSES UNLESS HEATING IS BETTER. NUDGED HIGHS DOWN A FEW DEGREES TO ACCOUNT FOR EARLY CLOUDS/SHRA AND POTENTIAL FOR QUICK DEVELOPMENT THIS AFTERNOON WITH ANY INSOLATION PER PWATS OF NEARLY 2 INCHES. GUIDANCE PUSHES A LOBE OF CONVECTION EAST/NE THIS EVENING AS THE WARM FRONT LIFTS NORTH AND THE COLD FRONT APPROACHES FROM THE WEST LATE. THINK BEST COVERAGE THROUGH MIDNIGHT OR SO WITH A RESIDUAL WAVE OVERHEAD BEFORE POSSIBLY SEEING A BREAK IN ALL EXCEPT THE NORTH LATE AS THE REGION SLIPS IN BETWEEN THE EXITING WARM FRONT AND UPSTREAM COLD FRONT. THE COLD FRONT MAY ALSO END UP BRINGING ANOTHER BAND OF SHRA INTO THE NW SLOPES TOWARD DAYBREAK...SO BLENDING POPS FROM LIKELYS MOST SPOTS TO INIT...TO MAINLY CHANCE IN ALL EXCEPT THE EAST/SE OVERNIGHT...AND OVER THE NW LATE. AGAIN MORE HEAVY RAIN POTENTIAL BUT EXPECT SHRA/TSRA TO MOVE A BIT MORE LATE AS WESTERLY FLOW DEEPENS SOME AHEAD OF THE COLD FRONT. STILL QUITE WARM/MUGGY WITH LOWS UPPER 60S/LOW 70S EXCEPT MID 60S VALLEYS AND IN SPOTS THAT RECEIVE HEAVIER RAINFALL. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM EDT MONDAY... MODELS HAVE OUR NEXT COLD FRONT MOVING ACROSS THE MOUNTAINS TUESDAY MORNING...STALLING NEAR THE BLUE RIDGE BY THE AFTERNOON. THE FRONT WILL EVENTUALLY CLEAR THE PIEDMONT TUESDAY EVENING...WAITING ON A SURFACE WAVE THAT WILL DEVELOP OVER THE CAROLINAS THEN MOVE OFF THE MID ATLANTIC COAST. WE CAN NOT RULE OUT SCATTERED SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS TUESDAY AFTERNOON...BUT THE MAJORITY OF THE STRONGER CONVECTION WILL BE ALONG AND EAST OF HWY 29. THE COVERAGE OF STRONG STORMS FOR THE FORECAST AREA WILL DEPEND ON THE LOCATION OF THE COLD FRONT AND THE TRACK OF THIS SURFACE WAVE. MOST MODELS ARE KEEPING THE STRONGER CONVECTION WITH THE SURFACE LOW OVER CENTRAL NORTH CAROLINA AND THE COASTAL PIEDMONT OF VIRGINIA. FOR NOW...WILL KEEP CHANCE POPS ACROSS THE FORECAST AREA. POPS WILL INCREASE IF THE FRONT REMAINS FARTHER TO THE WEST OR LOWER/DECREASING THROUGH THE AFTERNOON IF THE FRONT PUSHES EAST OF THE BLUE RIDGE. THE FRONT WILL BE ALONG THE CAROLINA COAST ON WEDNESDAY. THE DEW POINT FRONT WILL CROSS OVER THE REGION BY WEDNESDAY EVENING. WITH THE UPPER LEVEL TROUGH OVERHEAD AND LINGERING LOW LEVEL MOISTURE WEDNESDAY...A GOOD AMOUNT OF FAIR WEATHER CUMULUS CLOUDS WILL BE PRESENT...BUT NOT EXPECTING ANY TO PRODUCE MEASURE RAINFALL. TEMPERATURES ARE EXPECTED TO WARM TO NEAR NORMAL LEVELS TUESDAY. BEHIND THE FRONT...COOLER THAN NORMAL CONDITIONS ARE EXPECTED...70S WEST TO LOWER TO MID 80S EAST. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 200 PM SUNDAY... MODELS ARE ADVERTISING A RETREAT OF THE UPPER TROF OVER THE NORTHEAST THIS TIME FRAME. THE LARGE UPPER RIDGE OVER THE CENTRAL UNITED STATES SLIGHTLY RETROGRADES AND BUILDS NORTHEAST INTO THE OHIO VALLEY AS A LOW CUTS OFF SOMEWHERE AROUND THE NORTHERN GULF. AT THE SURFACE BY THURSDAY...HIGH PRESSURE WILL EXTEND FROM THE MID MISSISSIPPI VALLEY TO THE MID ATLANTIC REGION. THIS HIGH REMAINS OVER THE FORECAST AREA THROUGH FRIDAY. MODELS WERE BEGINNING TO SUGGEST A WEAK LOW OR SOME LEE TROUGHING MAY DEVELOP ON THE EASTERN SIDE OF THE APPALACHIANS ON SATURDAY. STILL NOT ENOUGH LIFT OR MOISTURE FOR ANY SUBSTANTIAL PROBABILITY OF PRECIPITATION. WILL BE STARTING THURSDAY MORNING WITH BELOW NORMAL MINIMUM TEMPERATURES THEN AIR MASS GRADUALLY MODERATES THROUGH SUNDAY. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... AS OF 1245 AM EDT MONDAY... STILL SEEING ISOLATED SLOW MOVING SHOWERS AROUND THE KLYH VICINITY AND EXPECT THESE TO LINGER A WHILE LONGER BEFORE PUSHING EAST AND WEAKENING WELL BEFORE DAYBREAK. THIS MAY BRING A PERIOD OF LOWER MVFR VSBY IN SHRA FOR KLYH OVER THE NEXT COUPLE OF HOURS ALONG WITH A MVFR CIG. OTRW EXPECTING ONLY ISOLATED ADDED SHOWER COVERAGE OVERNIGHT WITH LOTS OF STRATO-CU/AC PUSHING IN FROM THE NW AHEAD OF A WARM FRONT TO THE WEST. MODELS CONTINUE TO BRING A LOW END VFR/HIGH END MVFR CIGS OVER MOST OF THE AREA...SO TWEAKED CIGS DOWN IN SPOTS BUT NOT AS LOW AS CURRENT GUIDANCE. THUS WILL LEAN TOWARD VFR THROUGH MOST OF THE OVERNIGHT BUT SEEING SOME FOG POTENTIAL AT KBLF/KLWB/KBCB AS WELL AS KLYH IN THE PRE DAWN HOURS WHEN PERIODS OF IFR/MVFR COULD DEVELOP IF CLOUDS ARE LESS. BASED ON FORECAST CONSENSUS SHOULD SEE VFR TO MVFR CIGS MONDAY MORNING WITH SHOWERS AND A FEW THUNDERSTORMS ARRIVING INTO THE WEST TOWARD MIDDAY/18Z AND EAST BY 20Z. KEPT VCTS IN WITH MODERATE SHRA AT ALL SITES AFTER 18Z-20Z...WITH MVFR CIGS AT ALL EXCEPT VFR AT KDAN WHERE WILL HOLD OFF ON PRECIP. SHOWERS LIKELY TO LINGER OR REDEVELOP OVER THE WEST AFTER THE INITIAL CONVECTION SO LEAVING IN A MVFR MENTION INTO THE EVENING FOR ALL SITES EXCEPT OVER THE SOUTHEAST. SHOWERS AND ADDED TSRA COULD ALSO PERSIST OVER THE SOUTH AND WEST INTO LATER MONDAY NIGHT GIVEN OUTFLOW AND APPROACH OF THE COLD FRONT FROM THE WEST LATE. OTRW CUTTING BACK ON ADDED SHRA BY MIDNIGHT AT MOST LOCATIONS FOR NOW TO SEE HOW TRENDS UNFOLD LATER ON. EXTENDED AVIATION DISCUSSION... TUESDAY...SHOWERS AND STORMS INCREASE AGAIN ACROSS THE REGION THANKS TO BOTH A FRONTAL BOUNDARY ENTERING THE REGION AND A SHORTWAVE TROUGH PROGRESSING EASTWARD THROUGH THE OHIO VALLEY. MAINLY VFR CONDITIONS ARE EXPECTED EXCEPT SUB-VFR CONDITIONS WHERE CONVECTION BECOMES MORE ORGANIZED. STRONGER STORMS WILL BE POSSIBLE LATER TUESDAY...MAINLY ALONG AND EAST OF THE KLYH-KDAN CORRIDOR. BY WEDNESDAY INTO FRIDAY...ANOTHER AREA OF HIGH PRESSURE BUILDS INTO THE REGION MAKING FOR OVERALL VFR CONDITIONS. PATCHY LATE NIGHT AND EARLY MORNING MOUNTAIN AND RIVER VALLEY FOG WILL AGAIN BE POSSIBLE...THOUGH AIRMASS WILL LIKELY BE DRIER. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS/JH NEAR TERM...JH SHORT TERM...RCS LONG TERM...AMS AVIATION...DS/JH/JM/WP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1154 PM CDT SUN AUG 9 2015 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 214 PM CDT SUN AUG 9 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD FRONT STRETCHING FROM SOUTHWEST MINNESOTA TO THE WESTERN UPPER PENINSULA. THIS FRONT HAS BEEN MOSTLY INACTIVE SO FAR TODAY...OUTSIDE OF A FEW SHOWERS OVER VILAS COUNTY EARLY THIS MORNING. LOW STRATUS OVER NORTHERN WISCONSIN HAVE HELD BACK TEMPS SOMEWHAT...WHICH IS KEEPING INSTABILITY LIMITED TO UNDER 800 J/KG SO FAR THIS AFTERNOON. THE STRATUS IS SHOWING NO SIGNS OF BREAKING UP EITHER. BIGGER CONCERNS REVOLVE AROUND THE SHOWERS AND THUNDERSTORMS MOVING INTO WESTERN WISCONSIN ASSOCIATED WITH A SHORTWAVE IMPULSE. THUNDERSTORMS ARE EXPANDING WITHIN THE INSTABILITY AXIS OVER NORTHWEST WISCONSIN...AND A ROUGH TIMING SHOWS STORMS MOVING INTO NORTH-CENTRAL WISCONSIN IN THE 3-5PM RANGE. DUE TO THE LIMITED INSTABILITY...STILL THE SEVERE THREAT IS RATHER LOW. BUT SMALL HAIL AND GUSTY STRAIGHT LINE WINDS WILL BE POSSIBLE. FORECAST CONCERNS REVOLVE AROUND THUNDERSTORM POTENTIAL. TONIGHT...THE COLD FRONT WILL REMAIN NEARLY STATIONARY FOR THE REST OF THE AFTERNOON...AND THEN SHIFT SOUTHEAST AS THE SHORTWAVE IMPULSE MOVES ACROSS THE AREA THIS EVENING. SHOWERS AND THUNDERSTORMS NOW LOOK LIKELY ACROSS MOST OF THE AREA THIS EVENING...EXCEPT FOR MAYBE THE SOUTHERN TIER. HAVE INCREASED PRECIP CHANCES INTO THE LIKELY RANGE...AS THE SHORTWAVE SHOULD BE ABLE TO INTERACT WITH SOME OF LINGERING DAYTIME INSTABILITY. THE RAINFALL SHOULD HELP GIVE SOME SOUTHEAST PUSH TO THE COLD FRONT WHICH WILL MOVE INTO EAST-CENTRAL WISCONSIN LATE. WITH THE RAINFALL AND FRONT NEARBY...THINK LOW STRATUS AND/OR FOG WILL REDEVELOP AFTER MIDNIGHT. SOME DENSE FOG LIKE EARLY THIS MORNING IS POSSIBLE IN SPOTS. MONDAY...THE FRONT DOES NOT MAKE MUCH PROGRESS SOUTHWARD...LEAVING NORTHEAST WISCONSIN IN CLOSE PROXIMITY TO THE FRONT. THOUGH HAVE SOME CONCERN THAT TONIGHTS RAIN WILL PUSH THE FRONT SOUTH OF THE AREA...LEFT A CHANCE OF STORMS IN THE FORECAST DURING THE AFTERNOON OVER THE EAST. NO SEVERE STORMS ARE EXPECTED DUE TO MEAGER 0-6KM SHEAR OF 10 KTS. HIGHS TO RANGE FROM THE MID 70S TO LOW 80S. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 214 PM CDT SUN AUG 9 2015 A TRANSITION IN THE UPPER LEVEL FLOW IS EXPECTED STARTING TUESDAY...WHEN HIGH PRESSURE WILL STRENGTHEN OVER THE ROCKIES IN A BLOCKING PATTERN THAT WILL KEEP THE NORTHEAST U.S. UNDER A LOW PRESSURE TROUGH AND WISCONSIN UNDER A NORTHWEST FLOW. THIS SCENARIO WILL PRODUCE DRIER CONDITIONS IN GENERAL FOR NORTHEAST WISCONSIN...ALTHOUGH MODELS AGREE ON A CHANCE FOR PRECIPITATION LATER IN THE WORK WEEK AS A WEAK COLD FRONT SWEEPS DOWN ON THE NORTHWEST FLOW OUT OF CANADA. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1154 PM CDT SUN AUG 9 2015 A WEAK COLD FRONT WILL MOVE ACROSS THE REGION OVERNIGHT ACCOMPANIED BY SCATTERED SHOWERS. THERE ARE A LOT OF MIDDLE CLOUDS WHICH MAY BREAK UP ENOUGH FOR LOW CLOUDS OR FOG TO FORM LATER TONIGHT IN SOME AREAS. THE FOG WOULD END BY 15Z MONDAY WITH VFR CONDITION EXPECTED BY AFTERNOON. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ML AVIATION.......RDM
AREA FORECAST DISCUSSION
NWS RENO NV
541 AM PDT MON AUG 10 2015 .UPDATE... WE HAVE SEEN A FEW LIGHTNING STRIKES WITH THE WAVE LIFTING NORTH ACROSS NE CA AND FAR NW NV THIS MORNING. AS THIS WAVES MOVES NORTH THE TSTM/SHOWER ACTIVITY SHOULD END FROM SOUTH TO NORTH. WILL MAKE SOME MINOR ADJUSTMENTS TO TIMING OF THE WEATHER THIS MORNING TO ACCOUNT FOR THIS DECREASE FROM SOUTH TO NORTH. OTHERWISE NO CHANGES TO THE CURRENT FORECAST. 20 && .PREVIOUS DISCUSSION... /ISSUED 230 AM PDT MON AUG 10 2015/ SYNOPSIS... WEAK LOW PRESSURE WILL MOVE THROUGH THIS MORNING WITH A SLIGHT CHANCE OF THUNDERSTORMS NORTH OF INTERSTATE 80. SOUTH FLOW THEN RESUMES MONDAY AFTERNOON AS LOW PRESSURE DROPS OFF THE WEST COAST. DRY CONDITIONS WITH TYPICAL AFTERNOON BREEZES AND NEAR NORMAL TEMPERATURES ARE EXPECTED. WINDY CONDITIONS ARE POSSIBLE THURSDAY AS THE LOW MOVES INTO OREGON. SHORT TERM... WATER VAPOR AND IR SATELLITE IMAGERY SHOW A DEFINED UPPER LEVEL DISTURBANCE MOVING INTO THE CALIFORNIA INTERIOR THIS MORNING. AS A RESULT, ISOLATED VIRGA SHOWERS HAVE FORMED NORTH OF THE TAHOE BASIN NORTHWARD INTO NORTHERN LASSEN COUNTY. THE HRRR AND NAM CONCUR THAT ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THROUGH MID MORNING TODAY AS THIS WAVE MOVES NORTHWARD. ANY THUNDERSTORMS THAT DO RESULT WILL BE DRY WITH DRY LIGHTNING THE PRIMARY THREAT. NEW FIRE STARTS WILL BE POSSIBLE, BUT COVERAGE OF CELLS DOES NOT WARRANT A RED FLAG WATCH OR WARNING. AS FOR CONSIDERATIONS INVOLVING THE ROUGH FIRE IN THE SOUTHERN SIERRA OF CALIFORNIA, HAVE EXTENDED AREAS OF SMOKE THROUGH MID MORNING IN SOUTHERN MONO COUNTY WITH HAZE PERSISTING INTO THE AFTERNOON. FIRE ACTIVITY THIS MORNING WILL DETERMINE WHETHER OR NOT THESE CONDITIONS PERSIST INTO TUESDAY. OTHERWISE, LOW PRESSURE DEEPENS AND DROPS SOUTH IN THE EASTERN PACIFIC WITH HIGH PRESSURE LOCATED OVER THE WESTERN PLAINS OF THE UNITED STATES. THIS LEAVES THE SIERRA AND WESTERN NEVADA IN A NEUTRAL PRESSURE ADVECTION REGION RESULTING IN GENERALLY BENIGN WEATHER CONDITIONS. MOISTURE TRANSPORT VECTORS ARE NOT FAVORABLE FOR A MONSOONAL MOISTURE SURGE AT THIS TIME. THE MOST SIGNIFICANT IMPACTS THROUGH MID WEEK WILL COME FROM DRIER SOUTH TO WESTERLY FLOW EACH AFTERNOON WITH LOCALLY BREEZY CONDITIONS FROM TYPICAL AFTERNOON ZEPHYRS. AS SEEN WITH THE ROUGH FIRE IN THE SOUTHERN SIERRA OF CALIFORNIA, THESE WINDS AND DRY CONDITIONS COULD ACTIVATE HOLDOVERS ALLOWING FOR RAPID FIRE GROWTH. BOYD LONG TERM...THURSDAY THROUGH SUNDAY... MEDIUM RANGE OPERATIONAL MODELS ARE IN GOOD AGREEMENT AGAIN THIS CYCLE THROUGH EARLY SATURDAY. AFTER THAT DIFFERENCES APPEAR...AS THEY HAVE BEEN DOING SO FOR THE PAST FEW DAYS. UPPER LOW MOVES INTO THE PAC NW ON THURSDAY WITH STRONG LOW LEVEL PRESSURE AND THERMAL GRADIENTS OVER THE NORTHERN PART OF THE FORECAST AREA NORTH INTO OREGON. THESE STRONG GRADIENTS SHOULD DRIVE GUSTY WEST TO SOUTHWEST WINDS OVER THE NORTHERN 2/3RDS OF THE FORECAST AREA THURSDAY AFTERNOON AND EVENING. INCREASED MIXING WILL PUSH TEMPS AT OR ABOVE AVERAGE FOR ALL BUT THE FAR NORTHERN FORECAST AREA AND HUMIDITY VALUES SHOULD BE FAIRLY LOW. THIS COMBINATION WILL LIKELY PRODUCE CRITICAL FIRE WEATHER CONDITIONS FOR AT LEAST THE AREA NORTH OF HIGHWAY 50. UPPER LOW MOVES EAST FRIDAY WITH A LESSENING OF THE GRADIENT AND ATTENDANT WINDS. TEMPS WILL ALSO DECREASE OVER FAR NORTHERN AREAS OF THE CWA. DRY SOUTHWEST FLOW WILL KEEP ANY MENTION OF PCPN OUT OF THE FORECAST THROUGH AT LEAST SATURDAY. THE OPERATIONAL MODELS START TO DIVERGE SATURDAY WITH THE GFS HOLDING ON TO THE TROUGH A BIT LONGER WHILE THE ECMWF STARTS TO WEAKEN THE TROUGH AND BUILD A FLAT RIDGE. BY SUNDAY THE ECMWF IS MORE AGGRESSIVE BUILDING THE RIDGE AND THE GFS MAINTAINS A WEAK TROUGH. THE GEFS ENSEMBLE MEMBERS SHOW SOME SUPPORT FOR BOTH SOLUTIONS SO A COMPROMISE WAS MADE. THIS MEANT KEEPING THE HIGH TEMPS BELOW THE ECMWF GUIDANCE FOR SATURDAY AND SUNDAY. NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST. IF THE ECMWF SOLUTION IS MORE CORRECT THEN WE MIGHT SEE AND OUTSIDE CHANCE AT WEAK CONVECTION OVER THE FAR SOUTHERN CWA BY SUNDAY AS LIGHT UPSLOPE FLOW BRINGS A BIT MORE MOISTURE BACK TO THE REGION. OTHERWISE DRY WITH NEAR SEASONAL TEMPERATURES FOR THE EXTENDED PERIOD AND TYPICAL AFTERNOON WINDS ONCE WE GET PAST THURSDAY. 20 AVIATION... A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE EARLY THIS MORNING NORTH OF INTERSTATE 80 AS AN UPPER LEVEL WAVE OF LOW PRESSURE MOVES NORTH. OUTSIDE OF THE WAVE THERE SHOULD BE VFR CONDITIONS TODAY. TYPICAL SUMMER AFTERNOON WINDS ARE LIKELY TODAY WITH GUSTS EAST OF THE SIERRA IN THE 20-25 KT RANGE. HAZE AND SMOKE FROM CALIFORNIA FIRES WILL PRODUCE PERIODS OF LOWERED VISIBILITY TODAY AND TUESDAY. FAIRLY LIGHT WINDS TUESDAY. RIDGE WINDS BEGIN TO INCREASE WEDNESDAY AND THEN GUSTY WINDS DEVELOP THURSDAY AHEAD OF A SURFACE BOUNDARY THAT MOVES THROUGH THURSDAY NIGHT. INCREASED TURBULENCE IS HIGHLY PROBABLE FROM LATE WEDNESDAY THROUGH THURSDAY. 20 && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
401 AM MDT MON AUG 10 2015 .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 401 AM MDT MON AUG 10 2015 SHOWERS AND TSTMS CONTINUE EARLY THIS MORNING OVER THE ECNTRL PLAINS DUE TO COMBINATION OF FNTL PASSAGE AND SOME WK MID LVL ASCENT MOVING ACROSS. THIS ACTIVITY SHOULD BEGIN TO GRADUALLY END BY 12Z. FOR LATER TODAY AN UPPER LEVEL HIGH WILL BEGIN TO REBUILD OVER THE SRN ROCKIES WITH WLY FLOW ALOFT ACROSS NRN CO. MEANWHILE AS SFC HIGH PRES BEGINS TO MOVE ESE OF THE AREA THE LOW LVL FLOW WILL BECOME MORE SELY EAST OF THE MTNS AND KEEP DEEPER MOISTURE IN PLACE. PW`S ARE FCST TO INCREASE INTO THE 1.00 TO 1.25 RANGE BY MID TO LATE AFTN OVER NERN CO. AT THIS TIME CANNOT SEE ANY DEFINED DISTURBANCE AFFECTING THE AREA THIS AFTN OR EVENING HOWEVER GRIDDED DATA DOES SHOW SOME WL MID LVL ASCENT AFFECTING THE AREA. OVERALL SHOULD SEE A GOOD CHC OF STORMS DEVELOPING IN AND NR THE FOOTHILLS AND ACROSS THE PALMER DIVDE BY EARLY AFTN WITH ACTIVITY SPREADING SLOWLY EASTWARD ACROSS THE PLAINS FM LATE AFTN INTO THE EARLY EVENING HOURS. ONE THING THAT MODELS ARE NOT SHOWING IS A DENVER CYCLONE WHICH IS A BIT SURPRISING CONSIDERING THE LOW LVL FLOW WILL BE SELY. IF ONE DOES DVLP THE CONVERGENCE ZONE COULD END BEING A FOCUS FOR HEAVIER RAINFALL OVER PORTIONS OF THE URBAN CORRIDOR OR JUST TO THE EAST. WITH HIGH PW`S SOME STORMS WILL HAVE THE POTENTIAL TO PRODUCE 1 TO 2 INCHES OF RAIN WITH LOCALLY HIGHER AMOUNTS POSSIBLE IN A FEW SPOTS IF THE DENVER CONVERGENCE ZONE DOES DEVELOP. AS FOR TEMPS 850-700 MB TEMPS DROP A FEW MORE DEGREES TODAY SO READINGS WILL HOLD IN THE 80S ACROSS NERN CO. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 401 AM MDT MON AUG 10 2015 LITTLE CHANGE TO THE FORECAST PACKAGE FOR THE LATTER FORECAST PERIODS THIS TIME AROUND. MEDIUM RANGE MODELS CONTINUE INDICATING THAT A STRONG UPPER LEVEL RIDGE WILL BUILD OVER COLORADO AND THE FOUR CORNERS REGION THROUGH MOST OF THE WEEK. SPECIFIC HUMIDITY FIELDS CONTINUE SHOWING HEALTHY AMOUNTS OF MOISTURE ROTATING OVER THE STATE FROM THE SOUTH THROUGH THE FORECAST PERIOD. BUT MODEL QPF CHARTS ARE NO LONGER SHOWING ANY PERIODS OF PARTICULARLY HEAVY RAINFALL. MODEL SOUNDINGS FOR TUESDAY AND WEDNESDAY SHOW THAT PRECIPITABLE WATER VALUES AROUND DENVER WILL REMAIN AT OR SLIGHTLY ABOVE 1 INCH...WHICH MEANS THAT THUNDERSTORMS WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL. STORM MOTIONS ARE ALSO EXPECTED TO BE WEAK...MEANING THAT WE WILL HAVE TO WATCH OUT FOR LOCAL FLOODING PROBLEMS WHEN STORMS DEVELOP. MODEL SOUNDINGS ALSO SHOW THAT THE AIRMASS WILL BE MOST UNSTABLE ON TUESDAY...AND THEN STABILIZE LATER IN THE WEEK. THE INCREASE IN STABILITY WILL BE DUE TO WARMING MID-LEVEL TEMPERATURES UNDER THE CENTER OF THE SUBSIDENT HIGH PRESSURE ALOFT. THE EXPECTED PRESENCE OF THE SUBTROPICAL MOISTURE AT MID AND UPPER LEVELS WILL MAKE IT HARD TO COMPLETELY REMOVE THE MENION OF SHOWER ACTIVITY THOUGH. THEREFORE...THE FORECAST WILL HAVE THE HIGHEST CHANCES OF SHOWERS OVER THE MOUNTAINS IN THE AFTERNOONS AND EVENINGS WITH THE PLAINS HAVING A SLIGHT CHANCE OF THUNDERSTORMS IN THE EVENINGS. && .AVIATION...(FOR THE TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 401 AM MDT MON AUG 10 2015 LIGHT DRAINAGE WINDS HAVE DEVELOPED EARLY THIS MORNING HOWEVER ONCE MIXING OCCURS EXPECT WINDS WILL GRADUALLY BECOME MORE EARLY BY LATE MORNING AND THEN MORE SELY BY AFTN. NEITHER THE HRRR OR RAP IS SHOWING A DENVER CYCLONE THIS AFTN. IF ONE DOES DVLP THEN WIND DIRECTIONS COULD END UP BEING CONSIDERABLY DIFFERENT DEPENDING ON WHERE THE CONVERGENCE ZN SETS UP. TSTM THREAT WILL INCREASE BY EARLY AFTN WITH SOME POTENTIAL FOR LOWER CEILINGS/VISIBILITIES IF AIRPORT TAKES A DIRECT HIT FROM A STRONGER STORM. FURTHERMORE CURRENT DATA SUGGESTS TSTM THREAT COULD CONTINUE INTO THE EARLY EVENING HOURS AS WELL SO WILL HAVE TO KEEP IN AT LEAST A PROB GROUP THRU 03Z. OVERNIGHT THERE WILL BE SOME POTENTIAL FOR STRATUS/FOG TOWARDS MORNING BASED ON THE HI RES MODELS AS THEY SHOW A DENVER CYCLONE NR DIA. && .HYDROLOGY... ISSUED AT 401 AM MDT MON AUG 10 2015 A FEW THUNDERSTORMS MAY DROP FROM 1 TO 2 INCHES OF RAIN IN 45 MINUTES OR LESS ALONG THE FRONT RANGE...PLAINS AND ACROSS THE PALMER DIVIDE THIS AFTERNOON INTO THE EARLY EVENING HOURS. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM...DANKERS AVIATION...RPK HYDROLOGY...RPK
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1105 AM EDT MON AUG 10 2015 .SYNOPSIS... A PRESSURE RIDGE WILL PUSH FARTHER OFF THE COAST TODAY. MOISTURE WILL INCREASE IN THE FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL MOVE THROUGH THE AREA LATE TUESDAY AND TUESDAY NIGHT. NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE ASSOCIATED WITH THE FRONT. DRYING WITH A DIMINISHED SHOWER CHANCE WILL OCCUR BEHIND THE FRONT WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... THE RIDGE ALONG THE COAST WILL BE SHIFTING FARTHER OFFSHORE THROUGH TONIGHT. AN INCREASE IN MOISTURE SHOULD OCCUR IN A SOUTHERLY FLOW. THE MODELS INDICATE UPPER SUPPORT WILL OCCUR THROUGH TONIGHT WITH AN H5 DIFLUENT PATTERN. ENHANCED LIFT MAY OCCUR TONIGHT AHEAD OF SHORTWAVE TROUGH. THE CONVECTION ALLOWING MODELS GENERALLY SHOWED SCATTERED SHOWER AND THUNDERSTORM COVERAGE TODAY AND THIS APPEARS REASONABLE WITH SHORTWAVE TROUGH TIMING NOT DIURNALLY FAVORABLE. THE GUIDANCE CONSENSUS MOS SUPPORTED POPS OF 20 TO 30 PERCENT TODAY. THE THUNDERSTORM CHANCE SHOULD INCREASE TONIGHT AHEAD OF THE NEXT SHORTWAVE TROUGH. THE HRRR DISPLAYED CONSIDERABLE COVERAGE ABOUT TO ENTER THE FORECAST AREA FROM THE WEST TOWARD SUNSET. THE SPC WRF SHOWED THIS AREA DIMINISHING AS IT MOVED THROUGH THE FORECAST AREA DURING THE 800 PM TO 100 AM TIME FRAME. FORECASTED A POP AROUND 40 PERCENT CLOSE TO THE GUIDANCE CONSENSUS. FOLLOWED THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE TODAY. LEANED TOWARD THE WARMER GUIDANCE BECAUSE OF EXPECTED CLOUDINESS AND MIXING TONIGHT. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... CONVERGENCE INTO A PRE-FRONTAL TROUGH AND COLD FRONT TUESDAY AND TUESDAY NIGHT PLUS UPPER-LEVEL TROUGHING SHOULD LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS TUESDAY AND TUESDAY NIGHT. WE LEANED TOWARD THE HIGHER POP GUIDANCE. SHOWER AND THUNDERSTORM COVERAGE MAY BE GREATEST EARLY TUESDAY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH AND AGAIN TUESDAY EVENING NEAR STRONGER CONVERGENCE JUST AHEAD OF THE FRONT. THE MODELS INDICATE MODERATE INSTABILITY AND PRECIPITABLE WATER OVER 2 INCHES. THUNDERSTORMS WITH DAMAGING WIND AND EXCESSIVE RAIN WILL BE POSSIBLE. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE GFS AND ECMWF INDICATE UPPER TROUGHING CONTINUING OVER THE EASTERN PART OF THE NATION THROUGH THE MEDIUM-RANGE PERIOD. THE MODELS DISPLAY A FRONTAL SYSTEM LINGERING NEAR THE SOUTHEAST COAST. DEEP MOISTURE APPEARS TO REMAIN SOUTH AND EAST OF THE FORECAST AREA. THE GFS AND ECMWF MOS HAVE TEMPERATURES NEAR CLIMATOLOGY WITH POPS 10 TO 30 PERCENT. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS EXPECTED OUTSIDE OF SHOWER/THUNDERSTORM ACTIVITY THIS AFTERNOON AND TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP ACROSS THE AREA BY LATE AFTERNOON/EARLY THIS EVENING...BUT GIVEN LOW CONFIDENCE IN TIMING AND AREAL COVERAGE...HAVE NOT INCLUDED CONVECTION IN THE TAFS ATTM. WINDS WILL CONTINUE OUT OF THE SOUTH AT AROUND 5 TO 10 KNOTS THROUGH TONIGHT...BECOMING MORE SOUTHWESTERLY OVERNIGHT. EXTENDED AVIATION OUTLOOK...SHOWERS AND THUNDERSTORMS POSSIBLE TUESDAY THROUGH TUESDAY NIGHT AS AN APPROACHING FRONTAL BOUNDARY MOVES THROUGH THE REGION. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
744 AM EDT MON AUG 10 2015 .PREV DISCUSSION... /ISSUED 413 AM EDT MON AUG 10 2015/ SHORT TERM /TODAY THROUGH TUESDAY/... A COLD FRONT WILL IMPACT THE CWFA IN THE SHORT TERM PORTION OF THE FORECAST AREA. THE FRONT CURRENTLY STRETCHES FROM THE MID MISSISSIPPI RIVER VALLEY TO THE TENNESSEE VALLEY. THE BOUNDARY WILL SLIP SLOWLY SOUTH TODAY...AND CROSS MUCH OF THE FORECAST AREA ON TUESDAY. DEWPOINTS HAVE BEGUN TO CREEP UP ACROSS THE CWFA...A SIGN OF INCREASING LOW LEVEL MOISTURE. PRECIPITATION CHANCES WILL INCREASE TODAY AHEAD OF THE FROPA. HI-RES MODELS ARE SHOWING A RATHER ORGANIZED LINE OF SHOWERS AND THUNDERSTORMS MOVING SOUTH ACROSS NORTH AND CENTRAL GA THIS AFTERNOON. THE LOCAL WRF AND THE HRRR DO DIFFER A BIT...WITH THE WRF BEING LATER WITH THE CONVECTION. HAVE TRIED TO COMPROMISE ON TIMING. BOTH MODELS...HOWEVER...INDICATE VERY GOOD RAIN CHANCES ACROSS NORTHERN GA TODAY. SO...HAVE RAISED POPS TO LIKELY IN THAT REGION. ATMOS WILL BE FAVORABLE FOR STRONG TO ISOLATED SEVERE STORMS. GOOD SURFACE INSTABILITY WILL BE PRESENT...WITH AN ASSIST BY A SHORTWAVE DROPPING SOUTH IN THE MID LEVEL FLOW. MODELS CURRENTLY KEEP LAPSE RATES FAIRLY WEAK...BUT THE SHORTWAVE WILL PROVIDE SOME LIFT. COPIOUS CLOUD COVER SHOULD HELP LIMIT SEVERE STORM COVERAGE. THE MAIN FOCUS FOR TODAYS CONVECTION SHOULD BE ANY OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES FROM THE THUNDERSTORM COMPLEX CURRENTLY ACROSS THE MID MISSISSIPPI RIVER VALLEY. THE ACTUAL FRONTAL BOUNDARY WILL PROVIDE A FOCUS FOR STORMS TOMORROW. TEMPS SHOULD BE A FEW DEGREES COOLER THAN YESTERDAYS VALUES DUE TO THE INCREASED CLOUD COVER. TEMP/DEWPOINT VALUES REMAIN BELOW CRITICAL THRESHOLDS FOR A HEAT ADVISORY AT THIS TIME. NLISTEMAA LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... GUIDANCE IN DECENT AGREEMENT WITH AFOREMENTIONED FRONTAL BOUNDARY IN THE SHORT TERM LINGERING ACROSS THE SOUTHERN TIER OF THE CWA FOR TUESDAY NIGHT INTO WEDNESDAY...THEN FINALLY PUSHING JUST SOUTH OF THE AREA AND BECOMING MORE DIFFUSE THRU THE REST OF THE WORK WEEK. HAVE TRENDED CHANCE TO SLIGHT POPS ACCORDINGLY AND ADVECTION OF ABNORMALLY DRY AIR IN FROM THE NW WILL ALLOW FOR A RATHER PLEASANT WED AND THURS WITH SLIGHTLY BELOW NORMAL HIGHS AND RESULTANT AFTERNOON RH VALUES IN THE 40S. FOR FRIDAY INTO THE WEEKEND...A BROAD/WEAK AREA OF LOW PRESSURE LOOKS TO DEVELOP ACROSS THE NORTHERN GOM ALLOWING FOR SOME LOW LEVEL MOISTURE TRANSPORT OFF THE ATLANTIC. HAVE CONTINUED TO ADVERTISE A RETURN OF SLIGHT TO LOW END CHANCE POPS FOR PORTIONS OF THE AREA...MAINLY FOR DIURNALLY DRIVEN CONVECTION. NO OTHER CLEAR FORCING MECHANISM LOOKS TO BE PRESENT SO NOT EXPECTING ANYTHING WIDESPREAD AND RATHER STAGNANT AIRMASS IN PLACE SO DEVELOPMENT SHOULD BE TYPICAL SUMMERTIME OUTFLOW DRIVEN. TEMPS SHOULD BE SLIGHTLY WARMER THAN MIDWEEK BUT CLOSE TO NORMAL OR SLIGHTLY BELOW WITH ENHANCED CLOUD COVERAGE. BAKER && .AVIATION... 12Z UPDATE... HI-RES MODELS CONTINUE TO BRING AN ORGANIZED LINE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA THIS AFTERNOON. THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE SYSTEM AND HAS HAD MORE RUN TO RUN CONSISTENCY. WINDS WILL REMAIN ON THE WEST SIDE. //ATL CONFIDENCE...12Z UPDATE... MED CONFIDENCE ALL ELEMENTS. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 90 72 89 71 / 40 40 30 30 ATLANTA 90 74 88 72 / 40 40 30 20 BLAIRSVILLE 84 67 83 63 / 60 40 30 10 CARTERSVILLE 90 71 88 68 / 60 40 30 20 COLUMBUS 93 76 91 74 / 40 30 40 40 GAINESVILLE 87 72 87 71 / 60 40 30 20 MACON 92 74 90 73 / 40 30 40 40 ROME 91 72 89 68 / 60 40 30 10 PEACHTREE CITY 91 72 89 70 / 40 30 30 30 VIDALIA 92 73 92 74 / 30 20 40 50 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
633 AM EDT MON AUG 10 2015 .SYNOPSIS... A PRESSURE RIDGE WILL PUSH FARTHER OFF THE COAST TODAY. MOISTURE WILL INCREASE IN THE FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL MOVE THROUGH THE AREA LATE TUESDAY AND TUESDAY NIGHT. NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE ASSOCIATED WITH THE FRONT. DRYING WITH A DIMINISHED SHOWER CHANCE WILL OCCUR BEHIND THE FRONT WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... THE RIDGE ALONG THE COAST WILL BE SHIFTING FARTHER OFFSHORE THROUGH TONIGHT. AN INCREASE IN MOISTURE SHOULD OCCUR IN A SOUTHERLY FLOW. THE MODELS INDICATE UPPER SUPPORT WILL OCCUR THROUGH TONIGHT WITH AN H5 DIFLUENT PATTERN. ENHANCED LIFT MAY OCCUR THIS MORNING AND TONIGHT AHEAD OF SHORTWAVE TROUGHS. BELIEVE A LEAD SHORTWAVE TROUGH WAS HELPING SUPPORT THE SCATTERED SHOWERS IN THE FORECAST AREA EARLY THIS MORNING. THE CONVECTION ALLOWING MODELS GENERALLY SHOWED SCATTERED SHOWER AND THUNDERSTORM COVERAGE TODAY AND THIS APPEARS REASONABLE WITH SHORTWAVE TROUGH TIMING NOT DIURNALLY FAVORABLE. THE GUIDANCE CONSENSUS MOS SUPPORTED POPS OF 20 TO 30 PERCENT TODAY. THE THUNDERSTORM CHANCE SHOULD INCREASE TONIGHT AHEAD OF THE NEXT SHORTWAVE TROUGH. THE HRRR DISPLAYED CONSIDERABLE COVERAGE ABOUT TO ENTER THE FORECAST AREA FROM THE WEST TOWARD SUNSET. THE SPC WRF SHOWED THIS AREA DIMINISHING AS IT MOVED THROUGH THE FORECAST AREA DURING THE 800 PM TO 100 AM TIME FRAME. FORECASTED A POP AROUND 40 PERCENT CLOSE TO THE GUIDANCE CONSENSUS. FOLLOWED THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE TODAY. LEANED TOWARD THE WARMER GUIDANCE BECAUSE OF EXPECTED CLOUDINESS AND MIXING TONIGHT. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... CONVERGENCE INTO A PRE-FRONTAL TROUGH AND COLD FRONT TUESDAY AND TUESDAY NIGHT PLUS UPPER-LEVEL TROUGHING SHOULD LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS TUESDAY AND TUESDAY NIGHT. WE LEANED TOWARD THE HIGHER POP GUIDANCE. SHOWER AND THUNDERSTORM COVERAGE MAY BE GREATEST EARLY TUESDAY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH AND AGAIN TUESDAY EVENING NEAR STRONGER CONVERGENCE JUST AHEAD OF THE FRONT. THE MODELS INDICATE MODERATE INSTABILITY AND PRECIPITABLE WATER OVER 2 INCHES. THUNDERSTORMS WITH DAMAGING WIND AND EXCESSIVE RAIN WILL BE POSSIBLE. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE GFS AND ECMWF INDICATE UPPER TROUGHING CONTINUING OVER THE EASTERN PART OF THE NATION THROUGH THE MEDIUM-RANGE PERIOD. THE MODELS DISPLAY A FRONTAL SYSTEM LINGERING NEAR THE SOUTHEAST COAST. DEEP MOISTURE APPEARS TO REMAIN SOUTH AND EAST OF THE FORECAST AREA. THE GFS AND ECMWF MOS HAVE TEMPERATURES NEAR CLIMATOLOGY WITH POPS 10 TO 30 PERCENT. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... A FEW SHOWERS HAVE DEVELOPED OVER PORTIONS OF THE MIDLANDS AND CSRA EARLY THIS MORNING. GIVEN LATEST RADAR TRENDS...HAVE INCLUDED A TEMPO GROUP FOR SHOWERS FOR AGS/DNL/CAE/CUB UNTIL 13Z. CLOUDS AND A 15 TO 20 KNOT LOW LEVEL JET SHOULD LIMIT FOG POTENTIAL BEFORE SUNRISE. LIGHT SE WINDS EARLY BECOMING SOUTH TO SOUTHWEST 5 TO 10 KNOTS BY LATE MORNING. SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP ACROSS THE AREA BY LATE AFTERNOON/EARLY THIS EVENING...BUT GIVEN LOW CONFIDENCE IN TIMING AND AREAL COVERAGE...HAVE NOT INCLUDED CONVECTION IN THE TAFS ATTM. EXTENDED AVIATION OUTLOOK...SHOWERS AND THUNDERSTORMS POSSIBLE TUESDAY THROUGH TUESDAY NIGHT AS AN APPROACHING FRONTAL BOUNDARY MOVES THROUGH THE REGION. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 99
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT MON AUG 10 2015 .UPDATE... ISSUED AT 1045 AM CDT MON AUG 10 2015 UPDATED THE FORECAST DURING MID MORNING WITH DENSE FOG ADVISORY ENDING AT 9 AM ACROSS NORTHERN HALF OF CWA. WILL ISSUE ANOTHER UPDATE LATE THIS MORNING TO REMOVE MENTION OF PATCHY FOG THIS MORNING. OTHERWISE REST OF FORECAST LOOKS ON TRACK THIS AFTERNOON. HAVE 20-30% CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AS WARM AND HUMID CONDITIONS PREVAIL WITH DEWPOINTS OF 70-75F AND SEASONABLE HIGHS IN THE LOW TO MID 80S. A WEAK FRONTAL BOUNDARY JUST SE OF A RANTOUL TO DECATUR TO TAYLORVILLE LINE WILL PUSH SE ACROSS SOUTHEAST IL DURING THIS AFTERNOON GIVING ISOLATED SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF IT WHERE UNSTABLE AIRMASS WITH CAPES OF 1500-2500 J/KG. MEANWHILE A SHORT WAVE TROF OVER SE WI INTO IA WILL SHIFT SE INTO THE IL RIVER VALLEY LATER THIS AFTEROON GIVING A CHANCE OF SHOWERS/THUNDESTORMS THERE AS WELL. SPC KEEPS MARGINAL RISK OF SEVERE STORMS SE OF CWA THIS AFTERNOON. && .SHORT TERM...(TODAY) ISSUED AT 305 AM CDT MON AUG 10 2015 07Z/2AM SURFACE ANALYSIS SHOWS A 1010MB LOW OVER CENTRAL ILLINOIS...WITH A FRONTAL BOUNDARY EXTENDING SOUTHWESTWARD INTO THE OZARKS. A LARGE CLUSTER OF THUNDERSTORMS THAT DEVELOPED ALONG AN OLD OUTFLOW BOUNDARY IS ONGOING WELL SOUTH OF THE FRONT ACROSS SOUTHERN MISSOURI INTO FAR SOUTHERN ILLINOIS...HOWEVER THESE STORMS ARE DROPPING SOUTHWARD AWAY FROM THE KILX CWA. MEANWHILE...ANOTHER WEAK FRONT IS ANALYZED ACROSS CENTRAL IOWA WHERE A SECOND CLUSTER OF SHOWERS AND THUNDERSTORMS IS LOCATED. HRRR SUGGESTS THESE STORMS WILL WEAKEN AS THEY TRACK SLOWLY EASTWARD AND WILL NEVER REACH CENTRAL ILLINOIS. RAPIDLY WARMING CLOUD TOPS ON LATEST IR SATELLITE IMAGERY SUPPORT THIS THEORY...SO HAVE MAINTAINED A DRY FORECAST ACROSS THE ENTIRE AREA EARLY THIS MORNING. MAIN CONCERN EARLY ON WILL BE AREAS OF FOG THANKS TO AMPLE LOW-LEVEL MOISTURE...LIGHT WINDS...AND BREAKS IN THE OVERCAST. VSBYS HAVE OCCASIONALLY DROPPED TO AROUND 1/4 MILE ACROSS THE FAR NORTHERN CWA OVER THE PAST HOUR...SO WILL NEED TO MONITOR TRENDS CLOSELY FOR POTENTIAL DENSE FOG ADVISORY. AT THIS POINT...FOG HAS NOT BEEN CONSISTENTLY DENSE OR WIDESPREAD...SO WILL HOLD OFF ON AN ADVISORY. AS THE IOWA FRONT SAGS SOUTHEASTWARD...A FEW SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON DURING PEAK HEATING. WITH SURFACE DEWPOINTS REMAINING IN THE LOWER TO MIDDLE 70S...SBCAPE VALUES WILL REACH THE 1500 TO 2500J/KG RANGE. WEAK CONVERGENCE ALONG THE FRONT WILL BE ENOUGH TO TRIGGER WIDELY SCATTERED CONVECTION...PARTICULARLY ACROSS THE CENTRAL/NORTHERN CWA IN CLOSER PROXIMITY TO THE BOUNDARY. WILL CARRY 30 POPS ACROSS THIS AREA...TAPERING DOWN TO 20S ALONG/SOUTH OF I-70. .LONG TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 305 AM CDT MON AUG 10 2015 ANY LINGERING SHOWERS/THUNDERSTORMS WILL QUICKLY DISSIPATE AFTER SUNSET AS DAYTIME INSTABILITY WANES. HAVE THEREFORE INCLUDED A 20 POP ACROSS THE BOARD THROUGH MID-EVENING...THEN HAVE GONE DRY OVERNIGHT. COOLER/LESS HUMID AIR WILL GRADUALLY TRICKLE SOUTHWARD INTO THE AREA TONIGHT THROUGH THURSDAY AS HIGH PRESSURE BUILDS INTO THE REGION. AFTERNOON HIGHS WILL BE IN THE LOWER TO MIDDLE 80S WHILE OVERNIGHT LOWS DROP INTO THE UPPER 50S AND LOWER 60S EACH DAY. AFTER THAT...MODELS CONTINUE TO ADVERTISE A WEAKENING COLD FRONT DROPPING INTO THE REGION LATE IN THE WEEK. BOTH THE GFS AND ECMWF ARE SLIGHTLY SLOWER WITH THE BOUNDARY THAN IN PRIOR RUNS...WITH THE FRONT REMAINING ACROSS NORTHERN ILLINOIS UNTIL FRIDAY NIGHT/SATURDAY. WITH PRONOUNCED UPPER RIDGE INITIALLY POSITIONED OVER THE PLAINS/SOUTHERN CANADA BUILDING EASTWARD...RISING UPPER HEIGHTS WILL CREATE AN UNFAVORABLE ENVIRONMENT FOR THE ALREADY WEAK FRONT. AS SUCH...BOTH MODELS SUGGEST IT WILL COMPLETELY DISSIPATE BEFORE PASSING THROUGH CENTRAL ILLINOIS. HAVE MAINTAINED JUST A SLIGHT CHANCE POP ALONG/NORTH OF I-74 ON FRIDAY IN CASE BOUNDARY CAN GET CLOSE ENOUGH TO TRIGGER ISOLATED STORMS...THEN HAVE RETURNED TO A DRY FORECAST FRIDAY NIGHT THROUGH SUNDAY AS FRONT WASHES OUT. TEMPERATURES OVER THE WEEKEND WILL CLIMB BACK INTO THE UPPER 80S TO AROUND 90 BEFORE THE NEXT FRONT POTENTIALLY COMES INTO THE PICTURE BY NEXT MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 657 AM CDT MON AUG 10 2015 MAIN CONCERN INITIALLY WILL BE CIGS AND VSBYS IN DENSE FOG. VLIFR AND LIFR CONDITIONS WILL AFFECT ALL BUT BMI INITIALLY, WHERE IFR CONDITIONS PREVAIL AT 12Z. FORECAST SOUNDINGS SHOW WELL SATURATED SURFACE LAYER AND INVERSION, SO FOG MAY LINGER FOR SEVERAL HOURS AFTER SUNRISE. FOG SHOULD BEGIN TO DISSIPATE BETWEEN 13-15Z THIS MORNING WITH CIGS GRADUALLY LIFTING TO LOW VFR CONDITIONS BY LATE MORNING. SCATTERED TO BROKEN CUMULUS SHOULD REMAIN IN THE AFTERNOON WITH BASES IN THE 3000-4000 FOOT RANGE. SURFACE WINDS WILL BECOME NORTH-NORTHWEST THIS MORNING AT 8 TO 13 KTS. SPOTTY SHOWERS AND STORMS MAY DEVELOP THIS AFTERNOON INTO EARLY EVENING ALONG A TROUGH OF LOW PRESSURE PASSING FROM NW TO SE ACROSS THE AREA. HRRR AND RAP MODELS FOCUS CHANCES MAINLY FROM PIA AND NW 21Z-01Z, THEN DISSIPATE THE LINE OF SHOWERS. FOR NOW, WILL USE VCSH FOR PIA AND KEEP THE OTHER TAF SITES DRY. ANOTHER ROUND OF FOG COULD DEVELOP LATE TONIGHT, SO WE ADDED MVFR FOG ACROSS THE BOARD AFTER 11/09Z TO TREND IN THAT DIRECTION. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...07 SHORT TERM...BARNES LONG TERM...BARNES AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
658 AM CDT MON AUG 10 2015 .SHORT TERM...(TODAY) ISSUED AT 305 AM CDT MON AUG 10 2015 07Z/2AM SURFACE ANALYSIS SHOWS A 1010MB LOW OVER CENTRAL ILLINOIS...WITH A FRONTAL BOUNDARY EXTENDING SOUTHWESTWARD INTO THE OZARKS. A LARGE CLUSTER OF THUNDERSTORMS THAT DEVELOPED ALONG AN OLD OUTFLOW BOUNDARY IS ONGOING WELL SOUTH OF THE FRONT ACROSS SOUTHERN MISSOURI INTO FAR SOUTHERN ILLINOIS...HOWEVER THESE STORMS ARE DROPPING SOUTHWARD AWAY FROM THE KILX CWA. MEANWHILE...ANOTHER WEAK FRONT IS ANALYZED ACROSS CENTRAL IOWA WHERE A SECOND CLUSTER OF SHOWERS AND THUNDERSTORMS IS LOCATED. HRRR SUGGESTS THESE STORMS WILL WEAKEN AS THEY TRACK SLOWLY EASTWARD AND WILL NEVER REACH CENTRAL ILLINOIS. RAPIDLY WARMING CLOUD TOPS ON LATEST IR SATELLITE IMAGERY SUPPORT THIS THEORY...SO HAVE MAINTAINED A DRY FORECAST ACROSS THE ENTIRE AREA EARLY THIS MORNING. MAIN CONCERN EARLY ON WILL BE AREAS OF FOG THANKS TO AMPLE LOW-LEVEL MOISTURE...LIGHT WINDS...AND BREAKS IN THE OVERCAST. VSBYS HAVE OCCASIONALLY DROPPED TO AROUND 1/4 MILE ACROSS THE FAR NORTHERN CWA OVER THE PAST HOUR...SO WILL NEED TO MONITOR TRENDS CLOSELY FOR POTENTIAL DENSE FOG ADVISORY. AT THIS POINT...FOG HAS NOT BEEN CONSISTENTLY DENSE OR WIDESPREAD...SO WILL HOLD OFF ON AN ADVISORY. AS THE IOWA FRONT SAGS SOUTHEASTWARD...A FEW SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON DURING PEAK HEATING. WITH SURFACE DEWPOINTS REMAINING IN THE LOWER TO MIDDLE 70S...SBCAPE VALUES WILL REACH THE 1500 TO 2500J/KG RANGE. WEAK CONVERGENCE ALONG THE FRONT WILL BE ENOUGH TO TRIGGER WIDELY SCATTERED CONVECTION...PARTICULARLY ACROSS THE CENTRAL/NORTHERN CWA IN CLOSER PROXIMITY TO THE BOUNDARY. WILL CARRY 30 POPS ACROSS THIS AREA...TAPERING DOWN TO 20S ALONG/SOUTH OF I-70. .LONG TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 305 AM CDT MON AUG 10 2015 ANY LINGERING SHOWERS/THUNDERSTORMS WILL QUICKLY DISSIPATE AFTER SUNSET AS DAYTIME INSTABILITY WANES. HAVE THEREFORE INCLUDED A 20 POP ACROSS THE BOARD THROUGH MID-EVENING...THEN HAVE GONE DRY OVERNIGHT. COOLER/LESS HUMID AIR WILL GRADUALLY TRICKLE SOUTHWARD INTO THE AREA TONIGHT THROUGH THURSDAY AS HIGH PRESSURE BUILDS INTO THE REGION. AFTERNOON HIGHS WILL BE IN THE LOWER TO MIDDLE 80S WHILE OVERNIGHT LOWS DROP INTO THE UPPER 50S AND LOWER 60S EACH DAY. AFTER THAT...MODELS CONTINUE TO ADVERTISE A WEAKENING COLD FRONT DROPPING INTO THE REGION LATE IN THE WEEK. BOTH THE GFS AND ECMWF ARE SLIGHTLY SLOWER WITH THE BOUNDARY THAN IN PRIOR RUNS...WITH THE FRONT REMAINING ACROSS NORTHERN ILLINOIS UNTIL FRIDAY NIGHT/SATURDAY. WITH PRONOUNCED UPPER RIDGE INITIALLY POSITIONED OVER THE PLAINS/SOUTHERN CANADA BUILDING EASTWARD...RISING UPPER HEIGHTS WILL CREATE AN UNFAVORABLE ENVIRONMENT FOR THE ALREADY WEAK FRONT. AS SUCH...BOTH MODELS SUGGEST IT WILL COMPLETELY DISSIPATE BEFORE PASSING THROUGH CENTRAL ILLINOIS. HAVE MAINTAINED JUST A SLIGHT CHANCE POP ALONG/NORTH OF I-74 ON FRIDAY IN CASE BOUNDARY CAN GET CLOSE ENOUGH TO TRIGGER ISOLATED STORMS...THEN HAVE RETURNED TO A DRY FORECAST FRIDAY NIGHT THROUGH SUNDAY AS FRONT WASHES OUT. TEMPERATURES OVER THE WEEKEND WILL CLIMB BACK INTO THE UPPER 80S TO AROUND 90 BEFORE THE NEXT FRONT POTENTIALLY COMES INTO THE PICTURE BY NEXT MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 657 AM CDT MON AUG 10 2015 MAIN CONCERN INITIALLY WILL BE CIGS AND VSBYS IN DENSE FOG. VLIFR AND LIFR CONDITIONS WILL AFFECT ALL BUT BMI INITIALLY, WHERE IFR CONDITIONS PREVAIL AT 12Z. FORECAST SOUNDINGS SHOW WELL SATURATED SURFACE LAYER AND INVERSION, SO FOG MAY LINGER FOR SEVERAL HOURS AFTER SUNRISE. FOG SHOULD BEGIN TO DISSIPATE BETWEEN 13-15Z THIS MORNING WITH CIGS GRADUALLY LIFTING TO LOW VFR CONDITIONS BY LATE MORNING. SCATTERED TO BROKEN CUMULUS SHOULD REMAIN IN THE AFTERNOON WITH BASES IN THE 3000-4000 FOOT RANGE. SURFACE WINDS WILL BECOME NORTH-NORTHWEST THIS MORNING AT 8 TO 13 KTS. SPOTTY SHOWERS AND STORMS MAY DEVELOP THIS AFTERNOON INTO EARLY EVENING ALONG A TROUGH OF LOW PRESSURE PASSING FROM NW TO SE ACROSS THE AREA. HRRR AND RAP MODELS FOCUS CHANCES MAINLY FROM PIA AND NW 21Z-01Z, THEN DISSIPATE THE LINE OF SHOWERS. FOR NOW, WILL USE VCSH FOR PIA AND KEEP THE OTHER TAF SITES DRY. ANOTHER ROUND OF FOG COULD DEVELOP LATE TONIGHT, SO WE ADDED MVFR FOG ACROSS THE BOARD AFTER 11/09Z TO TREND IN THAT DIRECTION. && .ILX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR ILZ027>031- 036>038-041>043-045>051. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1118 AM EDT MON AUG 10 2015 .SYNOPSIS... ISSUED AT 1115 AM EDT MON AUG 10 2015 SCATTERED SHOWERS AND THUNDERSTORMS WILL PERSIST THIS AFTERNOON AND WILL BECOME MORE NUMEROUS OVER NORTHEAST INDIANA AND NORTHWEST OHIO AS A LOW PRESSURE SYSTEM MOVES ACROSS THE REGION. A FEW OF THESE STORMS MAY PRODUCE HEAVY RAIN AND GUSTY WINDS ALONG AND EAST OF INTERSTATE 69. HIGH PRESSURE AND DRY CONDITIONS WILL RETURN OVERNIGHT AND PERSIST UNTIL THE END OF THE WEEK. TODAY WILL BE THE LAST MUGGY DAY FOR A WHILE WITH HIGHS AROUND 80 DEGREES. LESS HUMID AND SLIGHTLY COOLER CONDITIONS EXPECTED FOR THE REST OF THE WEEK. && .UPDATE... ISSUED AT 1115 AM EDT MON AUG 10 2015 THE COMBINATION OF A WEAK MID LEVEL TROUGH AND LOW LEVEL THETAE ADVECTION AT THE NOSE OF LOW LEVEL MOISTURE AXIS HAS ALLOWED FOR SCATTERED SHOWER DEVELOPMENT ACROSS PORTIONS OF SOUTH CENTRAL LOWER MICHIGAN/FAR NORTHEAST INDIANA THIS MORNING. REGIONAL AMDAR SOUNDINGS JUST TO THE WEST DO DEPICT A RELATIVELY WARM 800-700 HPA WHICH IS LIKELY PROVIDING SOME INHIBITION FOR SFC BASED PARCELS ALONG ADVANCING FRONTAL BOUNDARY. AT LEAST TWO ADDITIONAL UPSTREAM PERTURBATIONS APPEAR POISED TO TRACK ACROSS THE SOUTHERN GREAT LAKES THIS EVENING...THE FIRST PUSHING INTO NORTHEAST ILLINOIS CURRENTLY...WITH A SECOND UPPER SHORT WAVE ENTERING SOUTHERN MINNESOTA. APPROACH OF THIS FIRST WAVE EARLY THIS AFTERNOON SHOULD ALLOW FOR SOME COOLING OF AFOREMENTIONED 800-700 HPA WARM LAYER AND A POTENTIAL OF SCATTERED SHOWER/ISOLATED THUNDERSTORM DEVELOPMENT EVEN BEHIND INITIAL WIND SHIFT. IT STILL APPEARS AS THOUGH MORE VIGOROUS CONVECTION SHOULD AFFECT AREAS EAST OF I-69 WHERE BETTER INSTABILITY AXIS SHOULD BE SITUATED. SEVERE THREAT STILL APPEARS LOW BASED ON MARGINAL INSTABILITY PROFILES AND OVERALL MODEST NATURE TO MID/UPPER FORCING. LOCALIZED HEAVIER DOWNPOURS STILL APPAER TO BE THE MAIN THREAT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM EDT MON AUG 10 2015 ANOTHER "GRUNGY" DAY IN STORE FOR THE LOCAL FORECAST AREA AS BROAD MID/UPPER LEVEL HEIGHT FALLS INDUCE MODEST SURFACE CYCLOGENESIS OVER THE GREAT LAKES WITH A VERY MOIST/MARGINALLY UNSTABLE ENVIRONMENT IN PLACE. THIS SETUP WILL LIKELY LEAD TO SEVERAL ROUNDS OF SPORADIC SHOWERS AND A FEW EMBEDDED THUNDERSTORMS. ALREADY A FEW ISOLATED SHOWERS POPPING UP ACROSS THE REGION AND SHOULD SEE THIS ACTIVITY GRADUALLY EXPAND DURING THE DAY AS DIFFUSE SURFACE BOUNDARY CURRENTLY OVER IOWA PUSHES EASTWARD AND CAPITALIZES ON SOME DEGREE OF DIURNAL HEATING. LAST FEW RUNS OF HRRR (AND TO A LESSER EXTENT THE RAP) FINALLY SEEM TO HAVE A LITTLE BETTER HANDLE ON THE CURRENT PICTURE AND SUGGEST PRECIP WILL EXPAND IN OUR NORTHWEST COUNTIES DURING THE LATE MORNING (~14Z) AND PUSH SOUTHEASTWARD THROUGH THE DAY. THIS SEEMS REASONABLE BASED ON LATEST RADAR MOSAIC/SURFACE OBS AND BACKGROUND SYNOPTIC PATTERN. HAVE THEREFORE MASSAGED POP GRIDS A BIT TO REFLECT THIS EXPECTED EVOLUTION. MIDLEVEL LAPSE RATES DO GET A LITTLE BETTER WITH APPROACHING TROUGH AND AMPLE LOW LEVEL MOISTURE WILL SUPPORT AROUND 1500 J/KG OF SBCAPE IN OUR EASTERN HALF THIS AFTERNOON DESPITE ABUNDANT CLOUD COVER. THIS SHOULD BE ENOUGH FOR DECENT COVERAGE OF THUNDERSTORMS BUT POTENTIAL FOR STRONG UPDRAFTS AND SEVERE WEATHER APPEARS LOW. PASSING MIDLEVEL SPEED MAX DOES YIELD GOOD DEEP LAYER SHEAR NUMBERS BUT WIND PROFILES IN THE 0-3KM LAYER ARE FAIRLY LIGHT AND...GIVEN LESS THAN STELLAR INSTABILITY VALUES...SUGGEST A LOW SEVERE RISK. MAIN THREAT WOULD BE AN ISOLATED STRONG/SEVERE DOWNBURST WHERE ANY POCKETS OF ENHANCED CAPE MANAGE TO DEVELOP. POCKETS OF HEAVY RAIN ALSO POSSIBLE GIVEN PW VALUES AROUND 1.75 INCHES BUT RECENT DRY SPELL AND OVERALL LACKLUSTER SYNOPTIC FORCING SUGGEST THREAT FOR WIDESPREAD FLOODING IS LOW. PRECIP SHOULD EXIT THE CWA BY THIS EVENING WITH COOLER AND MUCH DRIER AIR FILTERING SOUTH. AFTER A MUGGY DAY TODAY WITH HIGHS AROUND 80F...EXPECT DEWPOINTS AND LOW TEMPS TO DROP BACK INTO THE LOWER 60S OVERNIGHT. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 350 AM EDT MON AUG 10 2015 HIGH PRESSURE OVER THE UPR MIDWEST TUE WILL MOVE SE TO INDIANA WED PROVIDING FAIR WEATHER ACROSS OUR AREA. NW FLOW ALOFT WILL ADVECT A COOL CANADIAN AIRMASS S-SE INTO OUR AREA RESULTING IN BLO NORMAL TEMPS THROUGH THIS TIMEFRAME. DRY WX SHOULD CONT THU AS THE HIGH MOVES SE OF THE AREA WITH WAA ON THE BACKSIDE OF THE HIGH RESULTING IN A LITTLE WARMER TEMPS. A CDFNT IS EXPECTED TO DROP SLOWLY S-SE ACROSS THE GRTLKS THU NGT- FRI NGT. UPR RIDGE AXIS OVER THE ROCKIES IS ALSO EXPECTED TO MOVE EAST IN THIS TIMEFRAME SO A GENERAL WKNG TREND OF THE FRONT IS EXPECTED... BUT MEDIUM RANGE MODELS IN DECENT AGREEMENT SUGGESTING AT LEAST SOME CONVECTION MAY FORM ALONG/AHEAD OF THE FRONT SO HAVE ADDED LOW POPS FOR LATE IN THE WORKWEEK. BY THE WEEKEND THE UPR RIDGE AXIS SHOULD MOVE OVER OUR AREA PROVIDING DRY WX WITH ABOVE NORMAL TEMPS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 555 AM EDT MON AUG 10 2015 SHOWERS AND THUNDERSTORMS WILL GRADUALLY INCREASE IN COVERAGE TODAY AS A MIDLEVEL TROUGH APPROACHES THE REGION AND INTERSECTS A VERY MOIST AIRMASS. ISOLATED THUNDERSTORMS POSSIBLE THIS MORNING BUT BETTER CHANCES STILL LOOK TO BE AT KFWA THIS AFTERNOON. PERIODS OF MVFR CONDITIONS POSSIBLE AS WEAK FRONTAL BOUNDARY APPROACHES THE AREA BUT LATEST HI-RES/RAPID UPDATE GUIDANCE SUGGESTS CEILINGS WILL LIKELY REMAIN ABOVE FUEL ALTERNATE CRITERIA. CONDITIONS WILL IMPROVE BY THIS EVENING AS FRONT EXITS AND DRIER AIR FILTERS SOUTH. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...MARSILI SYNOPSIS...SKIPPER SHORT TERM...AGD LONG TERM...JT AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1120 AM EDT MON AUG 10 2015 .UPDATE... ISSUED AT 1120 AM EDT MON AUG 10 2015 14Z SFC ANALYSIS SHOWS A BROAD AREA OF LOW PRESSURE CROSSING THROUGH THE OHIO VALLEY NORTH OF KENTUCKY. A TRAILING COLD FRONT ASSOCIATED WITH THIS IS APPROACHING THE REGION. HOWEVER...AHEAD OF THIS BOUNDARY...AMPLE MOISTURE IS POOLING THROUGH EASTERN KENTUCKY WITH DEWPOINTS PREDOMINATELY IN THE LOWER 70S. MORNING BREAKS IN THE CLOUD COVER WILL HELP TO BUILD INSTABILITY THROUGH THE CWA AS TEMPERATURES ARE CURRENTLY IN THE UPPER 70S AND LOWER 80S ON THEIR WAY TO THE MID AND UPPER 80S. THE QUESTION IS WHETHER THE DEBRIS CLOUDS FROM THE EARLIER CONVECTION TO THE WEST WILL BE ENOUGH TO INHIBIT THE DEVELOPMENT OF WIDESPREAD AND ORGANIZED STORMS THROUGH THE AREA LATER THIS AFTERNOON. ALREADY A GROUP OF SHOWERS AND DEVELOPING STORMS ARE TRACKING INTO THE CUMBERLAND VALLEY. EXPECT THESE TO SPREAD INTO THE EARLY AFTERNOON WITH ADDITIONAL POCKETS OF CONVECTION EXPANDING TO THE NORTH AND EAST. THE LATEST HRRR MODEL AGREES WITH THIS SCENARIO WITH PEAK CONVECTIVE ACTIVITY TAKING PLACE OVER THE JKL CWA BETWEEN 19 AND 23Z. HAVE UPDATED THE GRIDS WITH THIS IN MIND AS WELL AS INFUSED THE LATEST SHORTBLEND GUIDANCE INTO THE T AND TD GRIDS. THOSE LATER ONES WERE UPDATED TO BETTER REFLECT THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS WITH A FRESHENED SET OF ZONES TO FOLLOW. UPDATE ISSUED AT 654 AM EDT MON AUG 10 2015 WSR-88D CONTINUES TO INDICATE SOME ISOLATED SHOWERS MOVING SOUTHEAST ACROSS PORTIONS OF EASTERN KY. EXPECT THIS MORNING SHOWER ACTIVITY TO REMAIN LIGHT. THE HEAVIER STORMS REMAINED SOUTH AND WEST OF THE REGION...AS MCS DIVED SOUTH TOWARD THE MORE UNSTABLE ENVIRONMENT WHERE UPPER 70S TO LOW 80 DEWPOINTS WERE REPORTED. STILL LOOKING AT INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS AS WE MOVE INTO THE AFTERNOON HOURS AHEAD OF A APPROACHING COLD FRONT. SOME MINOR UPDATES TO POPS AND THEN UPDATES TO TEMPS/DEWS/WINDS TO MATCH CURRENT CONDITIONS/TRENDS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 327 AM EDT MON AUG 10 2015 OVERALL MODELS REMAIN IN GOOD AGREEMENT WITH OVERARCHING SYNOPTIC PATTERN WITH TROUGHING CONTINUE TO DEEPEN IN THE EASTERN CONUS THROUGH THE PERIOD. THIS MORNING WE ARE BEING MET WITH A FEW SHOWERS SPREADING SE ACROSS PORTIONS OF EASTERN KY SEEN ON WSR- 88D. THIS HAS BEEN BROUGHT ON BY UPPER LEVEL WAVE AND INCREASING LOW LVL JET ACROSS THE OHIO/TN VALLEYS. THESE ARE DEVELOPING AHEAD OF AN APPROACHING SURFACE LOW PRESSURE AND COLD FRONT ACROSS THE MIDWEST THIS MORNING. WHILE WE DO HAVE SHOWERS AND PERHAPS A ISOLATED THUNDERSTORM THIS MORNING...BETTER CHANCES OF SHOWERS AND THUNDERSTORMS WILL EXIST AS WE MOVE INTO THE AFTERNOON AHEAD OF THE COLD FRONT. THE QUESTION IS HOW MUCH DOES ON GOING ACTIVITY AND CLOUD COVER PLAY ON THE OVERALL DESTABILIZATION...RIGHT NOW THIS LOOKS TO HAVE SOME AFFECTS BUT INCREASING LOW LEVEL JET AND SOME INSULATION LOOK TO BE ENOUGH TO FIRE OF STORMS THIS AFTERNOON. THIS LOOKS REASONABLE WITH CA MODELS SHOWING GOOD AGREEMENT OF BEST ACTIVITY GENERALLY AFTER 18Z. WHILE SOME OF THESE STORMS COULD BE STRONG...THINKING OVERALL SEVERE THREAT REMAINS LOW WITH SHEAR BEING MARGINAL AT BEST. THAT SAID MAIN THREAT WOULD BE ISOLATED DAMAGING WIND GUST...AND THIS LINES UP WELL WITH SPC THINKING AND OVERALL BROAD MARGINAL RISK. AFTER THIS SHOWER AND STORM ACTIVITY WILL WAIN IN THE EVENING AND OVERNIGHT HOURS AS FRONT SLOWLY MOVES EAST ACROSS THE REGION. MAINTAIN SOME INSTABILITY SHOWERS MAINLY IN THE FAR EAST THROUGH THE DAY ON TUESDAY. OTHERWISE SOME SPOTS ARE EXPECTED TO BEGIN THE DRYING OUT PROCESS IN THE WAKE OF THE COLD FRONT...AS WE TRANSITION TO W/NW FLOW. THE OTHER ISSUE IS HOW MUCH IF ANY FOG WILL BE SEEN EARLY TUESDAY GIVEN CLOUD COVER...SO RIGHT NOW LEFT OUT OF THE FORECAST GIVEN LOWER CONFIDENCE. THAT SAID VALLEYS AND AREAS THAT RECEIVED RAIN WILL HAVE THE BEST CHANCES OF SEEING REASONABLE PRODUCTION. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 327 AM EDT MON AUG 10 2015 QUIET LONG TERM PERIOD IN STORE AS AN EXPANSIVE UPPER LEVEL RIDGE OVER THE FOUR CORNERS REGION EXTENDS NORTHWARD INTO CENTRAL CANADA. WHILE A TROUGH REMAINS IN PLACE OVER THE EASTERN CONUS...THE HIGH AMPLITUDE RIDGE TO OUR WEST PLACES THE SOURCE REGION FOR OUR AIRMASS ALOFT OVER THE PRAIRIE PROVINCES OF CANADA...SO NOT MUCH OPPORTUNITY FOR MOISTURE RETURN. MODELS INDICATE A PIECE OF THE UPPER TROUGH OVER THE EAST WILL RETROGRADE SOUTHWEST AND POSSIBLY BREAK OFF INTO A WEAK CLOSED LOW OVER THE DEEP SOUTH. THIS MAY BRING ENOUGH LOW LEVEL MOISTURE IN OFF THE ATLANTIC TO CAUSE SOME ISOLATED DIURNAL CONVECTION OVER THE HIGHER TERRAIN OF THE SOUTHERN APPALACHIANS AT TIMES...BUT NOT LIKELY AFFECTING OUR AREA. THE NET RESULT SHOULD BE A DRY FORECAST WITH PLEASANT TEMPS AND HUMIDITY MID WEEK SLOWLY MODERATING BACK TO SEASONAL NORMS BY THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 700 AM EDT MON AUG 10 2015 VFR CONDITIONS PREVAIL THIS MORNING ACROSS EASTERN KY...HOWEVER SHORT DROPS TO MVFR VIS HAS BEEN SEEN IN SOME OF THE RAIN SHOWER ACTIVITY SEEN ON WSR-88D SWEEPS. MUCH OF THE MORNING SHOULD REMAIN VFR WITH BETTER STORM ACTIVITY REMAINING IN WESTERN END OF THE STATE INTO TN ASSOCIATED WITH MCS. FROPA IS STILL EXPECTED TO MOVE EASTWARD TOWARD THE REGION TODAY AND STORM ACTIVITY WILL FORM AHEAD OF THE FRONT. OVERALL THE CONVECTIVE ALLOWING MODELS BRING BEST CHANCES AFTER 18Z AND RIGHT NOW THINK WILL ADJUST TAF SITES IN THAT DIRECTION...GIVEN THAT SOME SITES LIKELY HAD VCTS STARTING TOO EARLY. AFTER THIS THE QUESTION OF HOW MUCH FOG DO WE GET IN THE WAKE OF THE PRECIP AND FROPA...GIVEN THE UNCERTAINTY WENT WITH JUST A GENERAL 4SM AFTER TEMPO GROUP FOR TS. OVERALL WINDS WILL REMAIN GENERALLY LIGHT THROUGH THE PERIOD AROUND 5 TO 10 KNOTS...WITH CAVEAT OF ANY OF THE STORMS HAVE THE POTENTIAL TO PRODUCE HIGHER GUST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...DJ LONG TERM...ABE AVIATION...DJ
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1008 AM EDT MON AUG 10 2015 .SYNOPSIS... A COLD FRONT APPROACHES FROM THE NORTHWEST TODAY...CROSSING THE MID ATLANTIC TONIGHT INTO TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY...REMAINING OVER THE REGION INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A QUICK UPDATE THIS MORNING TO FOCUS SHOWER COVERAGE ACROSS THE SRN PIEDMONT...SCNTRL VA...AND SRN RICHMOND METRO AREAS THROUGH THE REST OF THIS MORNING BEFORE SHOWERS DISSIPATE. PREVIOUS DISCUSSION (651 AM)...RADAR TRENDS INDICATE SHOWERS HOLDING TOGETHER BETTER THAN EXPECTED OVER AN INCREASINGLY MOIST AIR MASS. LATEST RAP GUIDANCE DEPICTS WEAK VORT MAX OVER THE REGION...PROVIDING SUBTLE FORCING OVER AN AREA OF ISENTROPIC LIFT...HELPING DRIVE THE SHOWERS. THIS LIFT IS PROGGED TO SPREAD NEWD ACROSS CENTRAL VA THRU MID MORNING. HIGH PRESSURE ALONG THE COAST WILL BEGIN TO WIN OUT...HELPING ERODE THE SHOWERS AS THEY SPREAD EAST OF INTERSTATE 95. MID LEVEL CLOUDS HAVE ALSO OVERSPREAD THE AREA...RESULTING IN A MOSTLY CLOUDY SKY (PARTLY CLOUDY SOUTHEAST). BASED ON CURRENT PRECIP AND LATEST STATISTICAL GUIDANCE...HAVE LOWERED TEMPS A FEW DEGS ACROSS THE PIEDMONT INTO CENTRAL VA. HIGHS IN THE LOW TO MID 80S. PREVIOUS DISCUSSION (407 AM)...LATEST REGIONAL RADAR MOSAIC DEPICTS AN AREA OF SHOWERS OVER THE ERN VA PIEDMONT EARLY THIS MORNING...SLOWING SPREADING EWD. THIS IN ASSOCIATION WITH AN AREA OF ISENTROPIC LIFT AND WEAKENING ENERGY ALOFT. EXPECT THIS AREA OF SHOWERS TO DISSIPATE AS IT SPREADS EWD INTO THE LOCAL PIEDMONT COUNTIES AS THE ENERGY ALOFT WEAKENS. HOWEVER...CLOUD COVER WILL CONTINUE TO OVERSPREAD MUCH OF THE AREA THIS MORNING...RESULTING IN A MOSTLY CLOUDY SKY. OTHERWISE...MID- LEVEL HEIGHT FALLS OVER THE MID- ATLANTIC REGION HAS ALLOWED MOISTURE TO RETURN EARLY THIS MORNING...WITH PWATS PROGGED AROUND 1.5 TO 1.8 INCHES AND DEWPOINTS WARMING INTO THE MID 60S. AT THE SFC...HIGH PRESSURE HAS ALIGNED ALONG THE COAST WITH A WARM FRONT LOCATED OVER THE OH/KY VALLEYS. A COLD FRONT IS RIGHT ON ITS HEELS OVER THE MIDWEST. FOR TODAY...A MORE POTENT SHORTWAVE TROUGH APPROACHES THE REGION FROM THE NW AS THE PARENT TROUGH CONTINUES TO DIG OVER THE ERN GREAT LAKES. THE MIDWEST COLD FRONT REACHES THE OH VALLEY LATE TODAY. EXPECT MOSTLY CLOUDY...BUT GENERALLY DRY CONDITIONS THIS MORNING. WILL MAINTAIN SLIGHT CHANCE POPS OVER THE PIEDMONT DUE TO THE AFOREMENTIONED WEAKENING WAVE AND ISENTROPIC LIFT. HIGH PRESSURE PUSHES OFFSHORE THIS AFTERNOON...OPENING THE DOOR FOR BETTER MOISTURE RETURN. H85 FLOW INCREASES...WITH PWATS PROGGED TO REACH ~2 INCHES THIS AFTERNOON. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN THIS AFTERNOON ALONG THE WARM FRONT AND LEAD SHORTWAVE...SPREADING EWD DURING THE LATE AFTERNOON. HAVE RETAINED CHANCE POPS GENERALLY ALONG AND WEST OF INTERSTATE 95...BUMPING UP TO LIKELY IN THE NW PIEDMONT COUNTIES. ERN PORTIONS WILL LIKELY BECOME PARTLY TO MOSTLY SUNNY BY AFTERNOON...WHILE WRN PORTIONS REMAIN MOSTLY CLOUDY. THIS WILL KEEP HIGHS IN THE LOW 80S THERE...WHILE AREA FARTHER EAST RISE INTO THE MID/UPPER 80S. LOUISA AND FLUVANNA COUNTIES MAY STRUGGLE TO GET OUT OF THE UPPER 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... STRONGER FORCING ARRIVES TONIGHT AS THE TROUGH CONTINUES TO DIG SOUTHEAST AND THE WIND FIELD STRENGTHENS ALOFT. THE WARM FRONT CROSSES THE REGION EARLY TONIGHT AS THE COLD FRONT LOCATES CENTRAL APPALACHIANS. A WARM/HUMID AND MARGINALLY UNSTABLE AIR MASS WILL BE IN PLACE OVER THE LOCAL AREA AHEAD OF THE WARM FRONT. THE RESULT WILL BE WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS. LIKELY POPS HAVE BEEN RETAINED. LATEST SREF GUIDANCE CONTINUES TO INDICATE STRONG MOISTURE FLUX (ON THE ORDER OF +4 TO +5 STD DEV) OVERNIGHT. HEAVY RAIN WORDING HAS BEEN RETAINED DUE TO THE COMBINATION OF STRONG FORCING AND MOISTURE FLUX. MBE/CORFIDI VECTORS AND FLOW INDICATE GOOD STORM MOTION...WHICH WILL LIMIT THE FLOODING POTENTIAL. FFG HAS ALSO RECOVERED FOLLOWING LAST WEEKS RAINFALL. MARGINAL SHEAR MAY PRODUCE SOME GUSTY WINDS UNDER THE STRONGEST STORMS. LOWS FORECAST IN THE LOW 70S. THE COLD FRONT PUSHES ACROSS THE LOCAL AREA TUESDAY AFTERNOON/EVENING...AND PUSHES OFFSHORE TUESDAY NIGHT. SHOWERS AND SOME EMBEDDED TSTMS SHOULD CONTINUE TUESDAY MORNING ACROSS ERN PORTIONS. HOWEVER...HEAVY RAIN POTENTIAL WILL DIMINISH AND THE MOISTURE FLUX ANOMALIES RELAX. ANOTHER ROUND OF SHOWERS/THUNDERSTORMS IS EXPECTED BY AFTERNOON AHEAD OF THE COLD FRONT. A WARM/MOIST AIR MASS REMAINS OVER THE REGION...BUT INSTABILITY WILL LARGELY BE LIMITED BY ANY CLEARING. MODELS AND BUFR SOUNDINGS INDICATE A DRY SLOT/MID LEVEL DRYING TUE AFTERNOON...WHICH WOULD RESULT IN BETTER INSTABILITY AND CHANCES FOR THUNDER. STICKING WITH THE LATEST SREF...MLCAPE VALUES PROGGED AROUND 1K J/KG TUE AFTERNOON. EFFECTIVE SHEAR ALSO EXPECTED IN THE 20 TO 30 KT RANGE. STRONG GUSTY WINDS WILL BE THE MAIN THREAT ALONG WITH LOCALLY HEAVY RAINFALL. CHC POPS WILL BE CONTINUED THROUGH THE AFTERNOON INLAND...WITH LIKELY NEAR THE COAST. TRIMMED BACK POPS SLIGHTLY...WITH HIGHS GENERALLY IN THE MID 80S. SHOWERS/TSTMS CONTINUE INTO TUESDAY EVENING...BEFORE TAPERING OFF NW- SE DURING THE LATE EVENING AND OVERNIGHT HOURS. HIGH PRESSURE AND A DRIER AIRMASS BUILDS INTO THE REGION WEDNESDAY. SOME HIGHER LOW- LEVEL MOISTURE IS EXPECTED TO LINGER ACROSS FAR SE VA/NE NC WEDNESDAY...SO A SLIGHT CHC POP FOR SHOWERS/TSTMS WILL BE FORECAST FOR THESE LOCATIONS. LOWS WEDNESDAY MORNING RANGE FROM THE MID 60S NW...TO THE LOW 70S SE. 850MB TEMPERATURES OF 14-16C SUPPORT HIGHS IN THE LOW/MID 80S. SREF/GEFS/WPC PROBABILITIES INDICATE HIGH PROBS FOR GREATER THAN ONE HALF INCH RAINFALL AMOUNTS ACROSS THE ENTIRE LOCAL AREA. PROBS DROP OFF WITH HIGHER QPF AMOUNTS...WITH ONLY A SLIGHT CHANCE OVER THE NE COUNTIES FOR AOA 1 INCH. HOWEVER...LOCALIZED AMOUNTS GREATER THAN ONE INCH ARE EXPECTED...ESPECIALLY UNDER STRONGER THUNDERSTORMS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE BUILDS BACK INTO THE MID ATLANTIC REGION LATE WED NIGHT INTO FRI...THUS SHUNTING THE STALLED SFC FRONT ALONG THE CAROLINA COAST FARTHER SWD AND AWAY FROM THE FORECAST AREA. OVERALL FORECAST WILL BE DRY WITH TEMPERATURES CLOSE TO SEASONAL NORMALS AND GENERALLY COMFORTABLE CONDITIONS. LONG RANGE MODELS BEGIN TO BRING UPPER LEVEL TROUGHING ACROSS THE NE CONUS ON SAT...HOWEVER THEY DIFFER ON HOW DEEP/FAR SOUTH THE TROUGHING EXTENDS INTO THE MID ATLANTIC REGION. LEANED TWD A DRY SOLUTION FOR NOW WITH A SLIGHT WARMING TREND. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... VFR CNDTNS XPCTD THRU MOST OF THE TAF PRD DESPITE A WEAK DISTURBANCE MOVING ACROSS THE RGN TDY. TSCTNS SHOWING PLNTY OF MID LEVEL MSTR WITH THIS FEATURE ALONG WITH SCT SHWRS MOVG EAST OF THE MTS THIS MORNING. KEPT SCT TO BKN CLDS AT 5K-12K FT. HIGH RES MODELS NOW INDCT THAT RIC SEES A FEW HRS PRD OF RAIN AT BEGINNING OF TAF PRD... BUT CIGS AND VSBY XPCTD TO REMAIN IN MVFR TO VFR RANGE. SBY/PHF MAY SEE SOME -RA BUT NO VSBY RESTRICTIONS XPCTD THIS MORNING. ADDNTL SHWRS DVLP W-E AFTR 06Z AND MOVE EAST AS MSTR OVRSPRDS THE AREA AHEAD OF APPRCHG CDFRNT. OUTLOOK...THE COLD FRONT CROSSES THE REGION LATE TUESDAY WITH CHC CONVECTION. DRY WEATHER RETURNS WEDNESDAY THROUGH FRIDAY. && .MARINE... SEAS SLOW TO SUBSIDE AND STILL AVG 4-5 FT GIVEN THE PERSISTENT (ALBEIT LIGHT) ONSHORE FLOW. GIVEN THE PROGGED SWELL DRCTN...SEAS WILL LIKELY REMAIN AT THESE LEVELS MOST OF THE DAY. THUS...HAVE XTNDD SCA HEADLINES FOR SEAS DESPITE LIGHT ESE FLOW. THNKG IS FOR OFFSHORE SEAS TO DROP BLO 5 FT BY TONIGHT ENDING THE CRNT SCA HEADLINES...HOWEVER DATA SUGGESTS SEAS BLDG BACK TO NR 5 FT OUT NEAR 20 NM ACROSS NRN CSTL WTRS TUE. WNDS BECOME SRLY TONIGHT THEN SW ON TUE AHEAD OF APPRCHG CD FRNT. SRLY CHANNELING NOTED IN ALL THE DATA BUT THE CHALLENGE WILL BE TO DETERMINE WHICH AREAS SEE WNDS AT SCA LVLS. HIGHEST CONFIDENCE FOR THIS TO OCCUR IS ACROSS THE MIDDLE CHES BAY (ANZ630) TONIGHT AND TUE SO HAVE ISSUED SCA HEADLINES FOR THIS ZONE. CONFIDENCE NOT HIGH ENUF TO PUT THE SRN CHES BAY IN ANY HEADLINE ATTM SO HAVE CAPPED THE SUSTAINED WINDS AT 15 KTS AND WILL LET THE DAY SHIFT REVIEW THE 12Z DATA TO DETERMINE IF ANY SCA`S ARE NEEDED THERE AHEAD OF THE FRNT. CDFRNT CROSSES THE WATERS LATE TUE NIGHT SHFTG WNDS TO THE NORTH WED. NOT MUCH OF A SURGE NOTED IN THE 12Z DATA BEHIND THE FROPA SO NO SCA HEADLINE ANTICIPATE ATTM. HIGH PRS TO THE NORTH BLDS ACROSS THE WTRS FOR THE REST OF THE WEEK WITH WNDS/SEAS BLO SCA THRESHOLDS. INCREASED RIP CURRENT THREAT TO MODERATE GIVEN NEARSHORE WAVES BTWN 3-4 FT AND A PERSISTENT ONSHORE SWELL. NOT OUT OF THE QSTN THAT A HIGH RISK MAY BE NEEDED ACROSS THE NRN OUTER BANKS TODAY AFTER GETTING SOME FEEDBACK FROM THE BEACH AREAS LATER THIS MORNING. && .TIDES/COASTAL FLOODING... A COASTAL FLOOD STATEMENT HAS BEEN ISSUED FOR THE BAY SIDE OF THE LWR MD ERN SHORE THRU MIDDAY...SPECIFICALLY FOR BISHOPS HEAD WHERE LEVELS ARE EXPECTED TO BE ABOUT A TENTH OF A FOOT BLO MINOR FLOOD THRESHOLDS. PREVIOUS DISCUSSION... AS EXPECTED...WATER HAVING A TUFF TIME GETTING OUT OF THE CHES BAY WITH THE WATER LEVELS ACROSS THE MIDDLE OF THE CHES BAY REMAINED ELEVATED DURING THE PAST HIGH TIDE CYCLE. BOTH BISHOPS HEAD AND CAMBRIDGE TOPPED OUT JUST BLO MINOR FLOODING THRESHOLDS. TONIGHTS HIGH TIDE CYCLE COMES CLOSE ONCE AGAIN TO MINOR FLOODING THRESHOLDS IN SVRL AREAS OF THE CHES BAY. DESPITE TIDAL ANOMALIES REMAINING AT 0.5 TO 1.0 FT ABOVE NORMAL OVR THE NEXT FEW HIGH TIDE CYCLES...THE VALUES SHOULD TOP OUT BLO MINOR FLOODING THRESHOLDS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ656- 658. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 4 PM EDT TUESDAY FOR ANZ630. && $$ SYNOPSIS...AJZ/SAM NEAR TERM...AJZ/BMD/SAM SHORT TERM...AJZ/SAM LONG TERM...BMD AVIATION...MPR MARINE...MPR TIDES/COASTAL FLOODING...MPR/MAS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
954 AM EDT MON AUG 10 2015 .SYNOPSIS... A COLD FRONT APPROACHES FROM THE NORTHWEST TODAY...CROSSING THE MID ATLANTIC TONIGHT INTO TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY...REMAINING OVER THE REGION INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A QUICK UPDATE THIS MORNING TO FOCUS SHOWER COVERAGE ACROSS THE SRN PIEDMONT...SCNTRL VA...AND SRN RICHMOND METRO AREAS THROUGH THE REST OF THIS MORNING BEFORE SHOWERS DISSIPATE. PREVIOUS DISCUSSION (651 AM)...RADAR TRENDS INDICATE SHOWERS HOLDING TOGETHER BETTER THAN EXPECTED OVER AN INCREASINGLY MOIST AIR MASS. LATEST RAP GUIDANCE DEPICTS WEAK VORT MAX OVER THE REGION...PROVIDING SUBTLE FORCING OVER AN AREA OF ISENTROPIC LIFT...HELPING DRIVE THE SHOWERS. THIS LIFT IS PROGGED TO SPREAD NEWD ACROSS CENTRAL VA THRU MID MORNING. HIGH PRESSURE ALONG THE COAST WILL BEGIN TO WIN OUT...HELPING ERODE THE SHOWERS AS THEY SPREAD EAST OF INTERSTATE 95. MID LEVEL CLOUDS HAVE ALSO OVERSPREAD THE AREA...RESULTING IN A MOSTLY CLOUDY SKY (PARTLY CLOUDY SOUTHEAST). BASED ON CURRENT PRECIP AND LATEST STATISTICAL GUIDANCE...HAVE LOWERED TEMPS A FEW DEGS ACROSS THE PIEDMONT INTO CENTRAL VA. HIGHS IN THE LOW TO MID 80S. PREVIOUS DISCUSSION (407 AM)...LATEST REGIONAL RADAR MOSAIC DEPICTS AN AREA OF SHOWERS OVER THE ERN VA PIEDMONT EARLY THIS MORNING...SLOWING SPREADING EWD. THIS IN ASSOCIATION WITH AN AREA OF ISENTROPIC LIFT AND WEAKENING ENERGY ALOFT. EXPECT THIS AREA OF SHOWERS TO DISSIPATE AS IT SPREADS EWD INTO THE LOCAL PIEDMONT COUNTIES AS THE ENERGY ALOFT WEAKENS. HOWEVER...CLOUD COVER WILL CONTINUE TO OVERSPREAD MUCH OF THE AREA THIS MORNING...RESULTING IN A MOSTLY CLOUDY SKY. OTHERWISE...MID- LEVEL HEIGHT FALLS OVER THE MID- ATLANTIC REGION HAS ALLOWED MOISTURE TO RETURN EARLY THIS MORNING...WITH PWATS PROGGED AROUND 1.5 TO 1.8 INCHES AND DEWPOINTS WARMING INTO THE MID 60S. AT THE SFC...HIGH PRESSURE HAS ALIGNED ALONG THE COAST WITH A WARM FRONT LOCATED OVER THE OH/KY VALLEYS. A COLD FRONT IS RIGHT ON ITS HEELS OVER THE MIDWEST. FOR TODAY...A MORE POTENT SHORTWAVE TROUGH APPROACHES THE REGION FROM THE NW AS THE PARENT TROUGH CONTINUES TO DIG OVER THE ERN GREAT LAKES. THE MIDWEST COLD FRONT REACHES THE OH VALLEY LATE TODAY. EXPECT MOSTLY CLOUDY...BUT GENERALLY DRY CONDITIONS THIS MORNING. WILL MAINTAIN SLIGHT CHANCE POPS OVER THE PIEDMONT DUE TO THE AFOREMENTIONED WEAKENING WAVE AND ISENTROPIC LIFT. HIGH PRESSURE PUSHES OFFSHORE THIS AFTERNOON...OPENING THE DOOR FOR BETTER MOISTURE RETURN. H85 FLOW INCREASES...WITH PWATS PROGGED TO REACH ~2 INCHES THIS AFTERNOON. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN THIS AFTERNOON ALONG THE WARM FRONT AND LEAD SHORTWAVE...SPREADING EWD DURING THE LATE AFTERNOON. HAVE RETAINED CHANCE POPS GENERALLY ALONG AND WEST OF INTERSTATE 95...BUMPING UP TO LIKELY IN THE NW PIEDMONT COUNTIES. ERN PORTIONS WILL LIKELY BECOME PARTLY TO MOSTLY SUNNY BY AFTERNOON...WHILE WRN PORTIONS REMAIN MOSTLY CLOUDY. THIS WILL KEEP HIGHS IN THE LOW 80S THERE...WHILE AREA FARTHER EAST RISE INTO THE MID/UPPER 80S. LOUISA AND FLUVANNA COUNTIES MAY STRUGGLE TO GET OUT OF THE UPPER 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... STRONGER FORCING ARRIVES TONIGHT AS THE TROUGH CONTINUES TO DIG SOUTHEAST AND THE WIND FIELD STRENGTHENS ALOFT. THE WARM FRONT CROSSES THE REGION EARLY TONIGHT AS THE COLD FRONT LOCATES CENTRAL APPALACHIANS. A WARM/HUMID AND MARGINALLY UNSTABLE AIR MASS WILL BE IN PLACE OVER THE LOCAL AREA AHEAD OF THE WARM FRONT. THE RESULT WILL BE WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS. LIKELY POPS HAVE BEEN RETAINED. LATEST SREF GUIDANCE CONTINUES TO INDICATE STRONG MOISTURE FLUX (ON THE ORDER OF +4 TO +5 STD DEV) OVERNIGHT. HEAVY RAIN WORDING HAS BEEN RETAINED DUE TO THE COMBINATION OF STRONG FORCING AND MOISTURE FLUX. MBE/CORFIDI VECTORS AND FLOW INDICATE GOOD STORM MOTION...WHICH WILL LIMIT THE FLOODING POTENTIAL. FFG HAS ALSO RECOVERED FOLLOWING LAST WEEKS RAINFALL. MARGINAL SHEAR MAY PRODUCE SOME GUSTY WINDS UNDER THE STRONGEST STORMS. LOWS FORECAST IN THE LOW 70S. THE COLD FRONT PUSHES ACROSS THE LOCAL AREA TUESDAY AFTERNOON/EVENING...AND PUSHES OFFSHORE TUESDAY NIGHT. SHOWERS AND SOME EMBEDDED TSTMS SHOULD CONTINUE TUESDAY MORNING ACROSS ERN PORTIONS. HOWEVER...HEAVY RAIN POTENTIAL WILL DIMINISH AND THE MOISTURE FLUX ANOMALIES RELAX. ANOTHER ROUND OF SHOWERS/THUNDERSTORMS IS EXPECTED BY AFTERNOON AHEAD OF THE COLD FRONT. A WARM/MOIST AIR MASS REMAINS OVER THE REGION...BUT INSTABILITY WILL LARGELY BE LIMITED BY ANY CLEARING. MODELS AND BUFR SOUNDINGS INDICATE A DRY SLOT/MID LEVEL DRYING TUE AFTERNOON...WHICH WOULD RESULT IN BETTER INSTABILITY AND CHANCES FOR THUNDER. STICKING WITH THE LATEST SREF...MLCAPE VALUES PROGGED AROUND 1K J/KG TUE AFTERNOON. EFFECTIVE SHEAR ALSO EXPECTED IN THE 20 TO 30 KT RANGE. STRONG GUSTY WINDS WILL BE THE MAIN THREAT ALONG WITH LOCALLY HEAVY RAINFALL. CHC POPS WILL BE CONTINUED THROUGH THE AFTERNOON INLAND...WITH LIKELY NEAR THE COAST. TRIMMED BACK POPS SLIGHTLY...WITH HIGHS GENERALLY IN THE MID 80S. SHOWERS/TSTMS CONTINUE INTO TUESDAY EVENING...BEFORE TAPERING OFF NW- SE DURING THE LATE EVENING AND OVERNIGHT HOURS. HIGH PRESSURE AND A DRIER AIRMASS BUILDS INTO THE REGION WEDNESDAY. SOME HIGHER LOW- LEVEL MOISTURE IS EXPECTED TO LINGER ACROSS FAR SE VA/NE NC WEDNESDAY...SO A SLIGHT CHC POP FOR SHOWERS/TSTMS WILL BE FORECAST FOR THESE LOCATIONS. LOWS WEDNESDAY MORNING RANGE FROM THE MID 60S NW...TO THE LOW 70S SE. 850MB TEMPERATURES OF 14-16C SUPPORT HIGHS IN THE LOW/MID 80S. SREF/GEFS/WPC PROBABILITIES INDICATE HIGH PROBS FOR GREATER THAN ONE HALF INCH RAINFALL AMOUNTS ACROSS THE ENTIRE LOCAL AREA. PROBS DROP OFF WITH HIGHER QPF AMOUNTS...WITH ONLY A SLIGHT CHANCE OVER THE NE COUNTIES FOR AOA 1 INCH. HOWEVER...LOCALIZED AMOUNTS GREATER THAN ONE INCH ARE EXPECTED...ESPECIALLY UNDER STRONGER THUNDERSTORMS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE BUILDS BACK INTO THE MID ATLANTIC REGION LATE WED NIGHT INTO FRI...THUS SHUNTING THE STALLED SFC FRONT ALONG THE CAROLINA COAST FARTHER SWD AND AWAY FROM THE FORECAST AREA. OVERALL FORECAST WILL BE DRY WITH TEMPERATURES CLOSE TO SEASONAL NORMALS AND GENERALLY COMFORTABLE CONDITIONS. LONG RANGE MODELS BEGIN TO BRING UPPER LEVEL TROUGHING ACROSS THE NE CONUS ON SAT...HOWEVER THEY DIFFER ON HOW DEEP/FAR SOUTH THE TROUGHING EXTENDS INTO THE MID ATLANTIC REGION. LEANED TWD A DRY SOLUTION FOR NOW WITH A SLIGHT WARMING TREND. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... VFR CNDTNS XPCTD THRU MOST OF THE TAF PRD DESPITE A WEAK DISTURBANCE MOVING ACROSS THE RGN TDY. TSCTNS SHOWING PLNTY OF MID LEVEL MSTR WITH THIS FEATURE ALONG WITH SCT SHWRS MOVG EAST OF THE MTS THIS MORNING. KEPT SCT TO BKN CLDS AT 5K-12K FT. HIGH RES MODELS NOW INDCT THAT RIC SEES A FEW HRS PRD OF RAIN AT BEGINNING OF TAF PRD... BUT CIGS AND VSBY XPCTD TO REMAIN IN MVFR TO VFR RANGE. SBY/PHF MAY SEE SOME -RA BUT NO VSBY RESTRICTIONS XPCTD THIS MORNING. ADDNTL SHWRS DVLP W-E AFTR 06Z AND MOVE EAST AS MSTR OVRSPRDS THE AREA AHEAD OF APPRCHG CDFRNT. OUTLOOK...THE COLD FRONT CROSSES THE REGION LATE TUESDAY WITH CHC CONVECTION. DRY WEATHER RETURNS WEDNESDAY THROUGH FRIDAY. && .MARINE... SEAS SLOW TO SUBSIDE AND STILL AVG 4-5 FT GIVEN THE PERSISTENT (ALBEIT LIGHT) ONSHORE FLOW. GIVEN THE PROGGED SWELL DRCTN...SEAS WILL LIKELY REMAIN AT THESE LEVELS MOST OF THE DAY. THUS...HAVE XTNDD SCA HEADLINES FOR SEAS DESPITE LIGHT ESE FLOW. THNKG IS FOR OFFSHORE SEAS TO DROP BLO 5 FT BY TONIGHT ENDING THE CRNT SCA HEADLINES...HOWEVER DATA SUGGESTS SEAS BLDG BACK TO NR 5 FT OUT NEAR 20 NM ACROSS NRN CSTL WTRS TUE. WNDS BECOME SRLY TONIGHT THEN SW ON TUE AHEAD OF APPRCHG CD FRNT. SRLY CHANNELING NOTED IN ALL THE DATA BUT THE CHALLENGE WILL BE TO DETERMINE WHICH AREAS SEE WNDS AT SCA LVLS. HIGHEST CONFIDENCE FOR THIS TO OCCUR IS ACROSS THE MIDDLE CHES BAY (ANZ630) TONIGHT AND TUE SO HAVE ISSUED SCA HEADLINES FOR THIS ZONE. CONFIDENCE NOT HIGH ENUF TO PUT THE SRN CHES BAY IN ANY HEADLINE ATTM SO HAVE CAPPED THE SUSTAINED WINDS AT 15 KTS AND WILL LET THE DAY SHIFT REVIEW THE 12Z DATA TO DETERMINE IF ANY SCA`S ARE NEEDED THERE AHEAD OF THE FRNT. CDFRNT CROSSES THE WATERS LATE TUE NIGHT SHFTG WNDS TO THE NORTH WED. NOT MUCH OF A SURGE NOTED IN THE 12Z DATA BEHIND THE FROPA SO NO SCA HEADLINE ANTICIPATE ATTM. HIGH PRS TO THE NORTH BLDS ACROSS THE WTRS FOR THE REST OF THE WEEK WITH WNDS/SEAS BLO SCA THRESHOLDS. INCREASED RIP CURRENT THREAT TO MODERATE GIVEN NEARSHORE WAVES BTWN 3-4 FT AND A PERSISTENT ONSHORE SWELL. NOT OUT OF THE QSTN THAT A HIGH RISK MAY BE NEEDED ACROSS THE NRN OUTER BANKS TODAY AFTER GETTING SOME FEEDBACK FROM THE BEACH AREAS LATER THIS MORNING. && .TIDES/COASTAL FLOODING... AS EXPECTED...WATER HAVING A TUFF TIME GETTING OUT OF THE CHES BAY WITH THE WATER LEVELS ACROSS THE MIDDLE OF THE CHES BAY REMAINED ELEVATED DURING THE PAST HIGH TIDE CYCLE. BOTH BISHOPS HEAD AND CAMBRIDGE TOPPED OUT JUST BLO MINOR FLOODING THRESHOLDS. TONIGHTS HIGH TIDE CYCLE COMES CLOSE ONCE AGAIN TO MINOR FLOODING THRESHOLDS IN SVRL AREAS OF THE CHES BAY. DESPITE TIDAL ANOMALIES REMAINING AT 0.5 TO 1.0 FT ABOVE NORMAL OVR THE NEXT FEW HIGH TIDE CYCLES...THE VALUES SHOULD TOP OUT BLO MINOR FLOODING THRESHOLDS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 4 PM EDT TUESDAY FOR ANZ630. SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ650-652-654. SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ656- 658. && $$ SYNOPSIS...AJZ/SAM NEAR TERM...AJZ/BMD/SAM SHORT TERM...AJZ/SAM LONG TERM...BMD AVIATION...MPR MARINE...MPR TIDES/COASTAL FLOODING...AKQ
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
651 AM EDT MON AUG 10 2015 .SYNOPSIS... A COLD FRONT APPROACHES FROM THE NORTHWEST TODAY...CROSSING THE MID ATLANTIC TONIGHT INTO TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY...REMAINING OVER THE REGION INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE... RADAR TRENDS INDICATE SHOWERS HOLDING TOGETHER BETTER THAN EXPECTED OVER AN INCREASINGLY MOIST AIR MASS. LATEST RAP GUIDANCE DEPICTS WEAK VORT MAX OVER THE REGION...PROVIDING SUBTLE FORCING OVER AN AREA OF ISENTROPIC LIFT...HELPING DRIVE THE SHOWERS. THIS LIFT IS PROGGED TO SPREAD NEWD ACROSS CENTRAL VA THRU MID MORNING. HIGH PRESSURE ALONG THE COAST WILL BEGIN TO WIN OUT...HELPING ERODE THE SHOWERS AS THEY SPREAD EAST OF INTERSTATE 95. MID LEVEL CLOUDS HAVE ALSO OVERSPREAD THE AREA...RESULTING IN A MOSTLY CLOUDY SKY (PARTLY CLOUDY SOUTHEAST). BASED ON CURRENT PRECIP AND LATEST STATISTICAL GUIDANCE...HAVE LOWERED TEMPS A FEW DEGS ACROSS THE PIEDMONT INTO CENTRAL VA. HIGHS IN THE LOW TO MID 80S. PREV DISCUSSION... LATEST REGIONAL RADAR MOSAIC DEPICTS AN AREA OF SHOWERS OVER THE ERN VA PIEDMONT EARLY THIS MORNING...SLOWING SPREADING EWD. THIS IN ASSOCIATION WITH AN AREA OF ISENTROPIC LIFT AND WEAKENING ENERGY ALOFT. EXPECT THIS AREA OF SHOWERS TO DISSIPATE AS IT SPREADS EWD INTO THE LOCAL PIEDMONT COUNTIES AS THE ENERGY ALOFT WEAKENS. HOWEVER...CLOUD COVER WILL CONTINUE TO OVERSPREAD MUCH OF THE AREA THIS MORNING...RESULTING IN A MOSTLY CLOUDY SKY. OTHERWISE...MID- LEVEL HEIGHT FALLS OVER THE MID- ATLANTIC REGION HAS ALLOWED MOISTURE TO RETURN EARLY THIS MORNING...WITH PWATS PROGGED AROUND 1.5 TO 1.8 INCHES AND DEWPOINTS WARMING INTO THE MID 60S. AT THE SFC...HIGH PRESSURE HAS ALIGNED ALONG THE COAST WITH A WARM FRONT LOCATED OVER THE OH/KY VALLEYS. A COLD FRONT IS RIGHT ON ITS HEELS OVER THE MIDWEST. FOR TODAY...A MORE POTENT SHORTWAVE TROUGH APPROACHES THE REGION FROM THE NW AS THE PARENT TROUGH CONTINUES TO DIG OVER THE ERN GREAT LAKES. THE MIDWEST COLD FRONT REACHES THE OH VALLEY LATE TODAY. EXPECT MOSTLY CLOUDY...BUT GENERALLY DRY CONDITIONS THIS MORNING. WILL MAINTAIN SLIGHT CHANCE POPS OVER THE PIEDMONT DUE TO THE AFOREMENTIONED WEAKENING WAVE AND ISENTROPIC LIFT. HIGH PRESSURE PUSHES OFFSHORE THIS AFTERNOON...OPENING THE DOOR FOR BETTER MOISTURE RETURN. H85 FLOW INCREASES...WITH PWATS PROGGED TO REACH ~2 INCHES THIS AFTERNOON. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN THIS AFTERNOON ALONG THE WARM FRONT AND LEAD SHORTWAVE...SPREADING EWD DURING THE LATE AFTERNOON. HAVE RETAINED CHANCE POPS GENERALLY ALONG AND WEST OF INTERSTATE 95...BUMPING UP TO LIKELY IN THE NW PIEDMONT COUNTIES. ERN PORTIONS WILL LIKELY BECOME PARTLY TO MOSTLY SUNNY BY AFTERNOON...WHILE WRN PORTIONS REMAIN MOSTLY CLOUDY. THIS WILL KEEP HIGHS IN THE LOW 80S THERE...WHILE AREA FARTHER EAST RISE INTO THE MID/UPPER 80S. LOUISA AND FLUVANNA COUNTIES MAY STRUGGLE TO GET OUT OF THE UPPER 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... STRONGER FORCING ARRIVES TONIGHT AS THE TROUGH CONTINUES TO DIG SOUTHEAST AND THE WIND FIELD STRENGTHENS ALOFT. THE WARM FRONT CROSSES THE REGION EARLY TONIGHT AS THE COLD FRONT LOCATES CENTRAL APPALACHIANS. A WARM/HUMID AND MARGINALLY UNSTABLE AIR MASS WILL BE IN PLACE OVER THE LOCAL AREA AHEAD OF THE WARM FRONT. THE RESULT WILL BE WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS. LIKELY POPS HAVE BEEN RETAINED. LATEST SREF GUIDANCE CONTINUES TO INDICATE STRONG MOISTURE FLUX (ON THE ORDER OF +4 TO +5 STD DEV) OVERNIGHT. HEAVY RAIN WORDING HAS BEEN RETAINED DUE TO THE COMBINATION OF STRONG FORCING AND MOISTURE FLUX. MBE/CORFIDI VECTORS AND FLOW INDICATE GOOD STORM MOTION...WHICH WILL LIMIT THE FLOODING POTENTIAL. FFG HAS ALSO RECOVERED FOLLOWING LAST WEEKS RAINFALL. MARGINAL SHEAR MAY PRODUCE SOME GUSTY WINDS UNDER THE STRONGEST STORMS. LOWS FORECAST IN THE LOW 70S. THE COLD FRONT PUSHES ACROSS THE LOCAL AREA TUESDAY AFTERNOON/EVENING...AND PUSHES OFFSHORE TUESDAY NIGHT. SHOWERS AND SOME EMBEDDED TSTMS SHOULD CONTINUE TUESDAY MORNING ACROSS ERN PORTIONS. HOWEVER...HEAVY RAIN POTENTIAL WILL DIMINISH AND THE MOISTURE FLUX ANOMALIES RELAX. ANOTHER ROUND OF SHOWERS/THUNDERSTORMS IS EXPECTED BY AFTERNOON AHEAD OF THE COLD FRONT. A WARM/MOIST AIR MASS REMAINS OVER THE REGION...BUT INSTABILITY WILL LARGELY BE LIMITED BY ANY CLEARING. MODELS AND BUFR SOUNDINGS INDICATE A DRY SLOT/MID LEVEL DRYING TUES AFTERNOON...WHICH WOULD RESULT IN BETTER INSTABILITY AND CHANCES FOR THUNDER. STICKING WITH THE LATEST SREF...MLCAPE VALUES PROGGED AROUND 1K J/KG TUES AFTERNOON. EFFECTIVE SHEAR ALSO EXPECTED IN THE 20 TO 30 KT RANGE. STRONG GUSTY WINDS WILL BE THE MAIN THREAT ALONG WITH LOCALLY HEAVY RAINFALL. CHC POPS WILL BE CONTINUED THROUGH THE AFTERNOON INLAND...WITH LIKELY NEAR THE COAST. TRIMMED BACK POPS SLIGHTLY...WITH HIGHS GENERALLY IN THE MID 80S. SHOWERS/TSTMS CONTINUE INTO TUESDAY EVENING...BEFORE TAPERING OFF NW- SE DURING THE LATE EVENING AND OVERNIGHT HOURS. HIGH PRESSURE AND A DRIER AIRMASS BUILDS INTO THE REGION WEDNESDAY. SOME HIGHER LOW- LEVEL MOISTURE IS EXPECTED TO LINGER ACROSS FAR SE VA/NE NC WEDNESDAY...SO A SLIGHT CHC POP FOR SHOWERS/TSTMS WILL BE FORECAST FOR THESE LOCATIONS. LOWS WEDNESDAY MORNING RANGE FROM THE MID 60S NW...TO THE LOW 70S SE. 850MB TEMPERATURES OF 14-16C SUPPORT HIGHS IN THE LOW/MID 80S. SREF/GEFS/WPC PROBABILITIES INDICATE HIGH PROBS FOR GREATER THAN ONE HALF INCH RAINFALL AMOUNTS ACROSS THE ENTIRE LOCAL AREA. PROBS DROP OFF WITH HIGHER QPF AMOUNTS...WITH ONLY A SLIGHT CHANCE OVER THE NE COUNTIES FOR AOA 1 INCH. HOWEVER...LOCALIZED AMOUNTS GREATER THAN ONE INCH ARE EXPECTED...ESPECIALLY UNDER STRONGER THUNDERSTORMS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE BUILDS BACK INTO THE MID ATLANTIC REGION LATE WED NIGHT INTO FRI...THUS SHUNTING THE STALLED SFC FRONT ALONG THE CAROLINA COAST FARTHER SWD AND AWAY FROM THE FORECAST AREA. OVERALL FORECAST WILL BE DRY WITH TEMPERATURES CLOSE TO SEASONAL NORMALS AND GENERALLY COMFORTABLE CONDITIONS. LONG RANGE MODELS BEGIN TO BRING UPPER LEVEL TROUGHING ACROSS THE NE CONUS ON SAT...HOWEVER THEY DIFFER ON HOW DEEP/FAR SOUTH THE TROUGHING EXTENDS INTO THE MID ATLANTIC REGION. LEANED TWD A DRY SOLUTION FOR NOW WITH A SLIGHT WARMING TREND. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... VFR CNDTNS XPCTD THRU MOST OF THE TAF PRD DESPITE A WEAK DISTURBANCE MOVING ACROSS THE RGN TDY. TCTNS SHOWING PLNTY OF MID LEVEL MSTR WITH THIS FEATURE ALONG WITH SCT SHWRS MOVG EAST OF THE MTS THIS MORNING. KEPT SCT TO BKN CLDS AT 5K-12K FT. HIGH RES MODELS NOW INDCT THAT RIC SEES A FEW HRS PRD OF RAIN AT BEGINNING OF TAF PRD... BUT CIGS AND VSBY XPCTD TO REMAIN IN MVFR TO VFR RANGE. SBY/PHF MAY SEE SOME -RA BUT NO VSBY RESTRICTIONS XPCTD THIS MORNING. ADDNTL SHWRS DVLP W-E AFTR 06Z AND MOVE EAST AS MSTR OVRSPRDS THE AREA AHEAD OF APPRCHG CDFRNT. OUTLOOK...THE COLD FRONT CROSSES THE REGION LATE TUESDAY WITH CHC CONVECTION. DRY WEATHER RETURNS WEDNESDAY THROUGH FRIDAY. && .MARINE... SEAS SLOW TO SUBSIDE AND STILL AVG 4-5 FT GIVEN THE PERSISTANT (ALBEIT LIGHT) ONSHORE FLOW. GIVEN THE PROGGED SWELL DRCTN...SEAS WILL LIKELY REMAIN AT THESE LEVELS MOST OF THE DAY. THUS...HAVE XTNDD SCA HEADLINES FOR SEAS DESPITE LIGHT ESE FLOW. THNKG IS FOR OFFSHORE SEAS TO DROP BLO 5 FT BY TONIGHT ENDING THE CRNT SCA HEADLINES...HOWEVER DATA SUGGESTS SEAS BLDG BACK TO NR 5 FT OUT NEAR 20 NM ACROSS NRN CSTL WTRS TUE. WNDS BECOME SRLY TONIGHT THEN SW ON TUE AHEAD OF APPRCHG CD FRNT. SRLY CHANNELING NOTED IN ALL THE DATA BUT THE CHALLENGE WILL BE TO DETERMINE WHICH AREAS SEE WNDS AT SCA LVLS. HIGHEST CONFIDENCE FOR THIS TO OCCUR IS ACROSS THE MIDDLE CHES BAY (ANZ630) TONIGHT AND TUE SO HAVE ISSUED SCA HEADLINES FOR THIS ZONE. CONFIDENCE NOT HIGH ENUF TO PUT THE SRN CHES BAY IN ANY HEADLINE ATTM SO HAVE CAPPED THE SUSTAINED WINDS AT 15 KTS AND WILL LET THE DAY SHIFT REVIEW THE 12Z DATA TO DETERMINE IF ANY SCA`S ARE NEEDED THERE AHEAD OF THE FRNT. CDFRNT CROSSES THE WATERS LATE TUE NIGHT SHFTG WNDS TO THE NORTH WED. NOT MUCH OF A SURGE NOTED IN THE 12Z DATA BEHIND THE FROPA SO NO SCA HEADLINE ANTICIPATE ATTM. HIGH PRS TO THE NORTH BLDS ACROSS THE WTRS FOR THE REST OF THE WEEK WITH WNDS/SEAS BLO SCA THRESHOLDS. INCREASED RIP CURRENT THREAT TO MODERATE GIVEN NEARSHORE WAVES BTWN 3-4 FT AND A PERSISTANT ONSHORE SWELL. NOT OUT OF THE QSTN THAT A HIGH RISK MAY BE NEEDED ACROSS THE NRN OUTER BANKS TODAY AFTER GETTING SOME FEEDBACK FROM THE BEACH AREAS LATER THIS MORNING. && .TIDES/COASTAL FLOODING... AS EXPECTED...WATER HAVING A TUFF TIME GETTING OUT OF THE CHES BAY WITH THE WATER LEVELS ACROSS THE MIDDLE OF THE CHES BAY REMAINED ELEVATED DURING THE PAST HIGH TIDE CYCLE. BOTH BISHOPS HEAD AND CAMBRIDGE TOPPED OUT JUST BLO MINOR FLOODING THRESHOLDS. TONIGHTS HIGH TIDE CYCLE COMES CLOSE ONCE AGAIN TO MINOR FLOODING THRESHOLDS IN SVRL AREAS OF THE CHES BAY. DESPITE TIDAL ANOMALIES REMAINING AT 0.5 TO 1.0 FT ABOVE NORMAL OVR THE NEXT FEW HIGH TIDE CYCLES...THE VALUES SHOULD TOP OUT BLO MINOR FLOODING THRESHOLDS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 4 PM EDT TUESDAY FOR ANZ630. SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ650-652-654. SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ656- 658. && $$ SYNOPSIS...AJZ/SAM NEAR TERM...AJZ/SAM SHORT TERM...AJZ/SAM LONG TERM...BMD AVIATION...MPR MARINE...MPR TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
734 AM EDT MON AUG 10 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 509 AM EDT MON AUG 10 2015 WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A RIDGE OVER THE ROCKIES WITH DOWNSTREAM TROF BEGINNING TO DEEPEN FROM HUDSON BAY S INTO THE GREAT LAKES. IN THE DEVELOPING NW FLOW INTO THE GREAT LAKES...THERE IS ONE SHORTWAVE OF NOTE UPSTREAM E OF LAKE WINNIPEG ALONG THE ONTARIO/MANITOBA BORDER. CLOSER TO HOME...SCT SHRA CONTINUE EARLY THIS MORNING OVER ROUGHLY THE E HALF UPPER MI...AHEAD OF COLD FRONT. WILL CONTINUE TO CARRY SCT SHRA OVER THE ERN FCST AREA THIS MORNING AHEAD OF SLOW MOVING COLD FRONT. MIGHT BE A FEW RUMBLES OF THUNDER. WHERE CLOUDS SCATTER OUT...EXPECT SOME FOG UNTIL MID MORNING... ESPECIALLY IN THOSE AREAS WHERE RAINFALL HAS OCCURRED OVER THE LAST 12HRS. THIS AFTN...UNDER NNW FLOW...LAKE BREEZE COMPONENTS TO WIND WILL LEAD TO AN AREA OF CONVERGENCE IN SCNTRL UPPER MI. WITH POTENTIAL OF 50-200J/KG OF MLCAPE PER GFS/RAP/HRRR...ISOLD SHRA/TSTM MAY DEVELOP (NAM LOOKS WAY TOO HIGH WITH MLCAPES OVER 1000J/KG). WITH MOST OF THE HIGH RES MODEL GUIDANCE SHOWING SOME CONVECTION IN THAT AREA...WILL INCLUDE SCHC TO LOW CHC POPS IN SCNTRL UPPER MI THIS AFTN. AHEAD OF THE LAKE BREEZE OFF LAKE SUPERIOR...MAY SEE A FEW SHRA/TSRA E TOWARD KISQ/KERY AS WELL. AS SHORTWAVE CURRENTLY E OF LAKE WINNIPEG DROPS SE...REACHING WRN LAKE SUPERIOR THIS EVENING...THERE SHOULD BE QUITE A BIT OF SHRA AND SOME TSTMS DEVELOPING NW OF LAKE SUPERIOR THIS AFTN. THIS CONVECTION WILL SPREAD OUT OVER NW LAKE SUPERIOR IN THE AFTN. NOT SURE HOW FAR THIS ACTIVITY WILL SPREAD BEFORE DISSIPATING OVER THE COOLER MARINE LAYER. HOWEVER...WITH WATER NOT AS COLD AS EARLIER IN THE SUMMER AND WITH SUPPORT FROM DECENT LOOKING SHORTWAVE...SOME OF THIS ACTIVITY CERTAINLY HAS THE POTENTIAL TO SURVIVE IN A WEAKENED STATE INTO NW UPPER MI LATE THIS AFTN/EARLY EVENING. ANY -SHRA THAT SURVIVE THE TRIP ACROSS THE LAKE INTO NW UPPER MI WILL DISSIPATE THIS EVENING AS SHORTWAVE QUICKLY MOVES E OF THE AREA. THIS WILL LEAD TO A QUIET OVERNIGHT. SINCE GFS AND ESPECIALLY NAM SUGGEST AN INCREASE IN LOW CLOUDS OCCURRING LATE IN THE NIGHT INTO TUE MORNING...CLOUD COVERAGE WAS TRENDED UP OVERNIGHT... ESPECIALLY ACROSS THE N WHERE UPSLOPE WIND SHOULD AID CLOUD DEVELOPMENT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 240 AM EDT MON AUG 10 2015 THE 500MB TROUGH SET UP ACROSS MUCH OF EASTERN CANADA AND THE EASTERN US. THE LAST SHORTWAVE OVER W LAKE SUPERIOR AT 12Z TUESDAY WILL EXPAND ACROSS E UPPER MI THROUGH THE AFTERNOON AND EVENING HOURS. WHILE THIS AND THE STEADY N-NNW WINDS WILL KEEP CLOUDS STUCK OVER THE E HALF...LINGERING PRECIP IS STILL UNKNOWN ESPECIALLY WITH PW VALUES DIMINISHING THROUGH FROM A MAX OF AROUND 1.25 EARLY IN THE DAY TO AROUND 1 IN BY MID AFTERNOON TUESDAY. THE SFC HIGH STRETCHING FROM HUDSON BAY DOWN THROUGH THE CENTRAL PLAINS TUESDAY MORNING WILL SETTLE ACROSS THE CWA BY 06Z WEDNESDAY. THE CANADIAN/ECMWF/AND GFS ARE ALL BRINGING IN ADDITIONAL PRECIP WEDNESDAY ASSOCIATED WITH A WARM FRONT EXTENDING FROM A LOW WAY UP IN N CENTRAL CANADA. THIS WILL COINCIDE WITH THE SFC RIDGE SHIFTING SLIGHTLY TO THE SE. THE NAM IS LESS IMPRESSIVE...AND HAS ONLY INCREASED CLOUD COVER. GIVEN THE OVERALL LIMITED MOISTURE...WILL KEEP POPS TO A MINIMUM. THE SFC LOW WILL SHIFT E AND STRETCH FROM N CANADA THROUGH HUDSON BAY BY THURSDAY AFTERNOON...WITH THE COLD FRONT SET UP ACROSS ONTARIO...NW LAKE SUPERIOR AND CENTRAL MN. LOOK FOR A BETTER CHANCE OF SHOWERS THURSDAY AS THE FRONT ROLLS THROUGH...SHIFTING SE OF THE CWA BY MID MORNING FRIDAY. INCREASED WIND GUSTS A BIT MORE DUE TO INCREASED MIXING AROUND THE COLD FRONT. LOOK FOR HIGH PRESSURE TO QUICKLY BUILD IN FRIDAY...AND REMAIN THROUGH SATURDAY...WITH DRY WEATHER FIGURED. WAA WILL BEGIN AGAIN SATURDAY NIGHT AS THE LARGE AREA OF HIGH PRESSURE SHIFTS E. THE ECMWF IS QUICKER TO HAVE THE HIGH SHIFT E IN ADVANCE OF THE NEXT CANADIAN LOW AND ASSOCIATED COLD FRONT FOR SUNDAY-MONDAY. WILL GO WITH A GENERAL BLEND FOR THE WEEKEND ON THE TIMING. WHILE TS MAY BE MORE ALIGNED NEAR THE COLD FRONT...WILL GO WITH GENERAL SHOWERS AND THUNDERSTORMS AT THIS POINT...WHICH WILL NEED TO BE FINE TUNED AS THE TIME NEARS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 733 AM EDT MON AUG 10 2015 IN THE WAKE OF A COLD FRONT THAT HAS PASSED...VFR CONDITIONS SHOULD PREVAIL THRU THE FCST PERIOD AT KIWD/KCMX/KSAW. THERE MAY BE A BRIEF PERIOD OF HIGH MVFR CIGS THIS MORNING AS DAYTIME HEATING LEADS TO CUMULUS DEVELOPMENT...AND THEN NEAR OR JUST AFTER THIS FCST PERIOD...THERE ARE SOME INDICATIONS THAT LOW CLOUDS (LOW MVFR CIGS/PERHAPS IFR) MAY DEVELOP...MAINLY AT KSAW. AN APPROACHING DISTURBANCE WILL GENERATE SHOWERS NW OF LAKE SUPERIOR TODAY. SOME OF THESE SHOWERS MAY BE ABLE TO REACH UPPER MI LATE THIS AFTN/EARLY THIS EVENING BEFORE DISSIPATING. POTENTIAL OF THESE SHRA REACHING ANY OF THE TERMINALS (KCMX IN PARTICULAR) IS TOO LOW TO INCLUDE A MENTION IN FCST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 509 AM EDT MON AUG 10 2015 IN THE WAKE OF A COLD FRONT CROSSING THE UPPER LAKES...W TO NW WINDS WILL BEGIN TO INCREASE TODAY ACROSS LAKE SUPERIOR...THOUGH WINDS WILL REMAIN UNDER 20KT. ANY FOG OVER THE LAKE SHOULD GRADUALLY DISSIPATE. TONIGHT/TUE...PRES GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE TO 10-20KT OUT OF THE SW INTO THU AHEAD OF THE NEXT APPROACHING COLD FRONT. DEPENDING HOW MUCH THE PRES GRADIENT TIGHTENS...WILL NEED TO WATCH FOR THE POTENTIAL OF WINDS TO INCREASE FURTHER INTO THE 15-25KT RANGE...WITH PERHAPS GUSTS TO 30KT AT THE HIGHEST OBS PLATFORMS. WINDS WILL DIMINISH AFTER THE FRONT PASSES. EXPECT LIGHTER WINDS UNDER 15KT ON FRI AS HIGH PRES BUILDS INTO THE UPPER LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1037 AM CDT MON AUG 10 2015 .UPDATE... ISSUED AT 1037 AM CDT MON AUG 10 2015 UPDATED THE FORECAST THROUGH AROUND MIDNIGHT...FOCUSING ON PCPN CHANCES AND CLOUD COVER. LATEST MODEL SOUNDINGS AND HRRR RUNS SUGGEST THERE WILL BE SCT/BKN CUMULUS ACROSS MUCH OF THE FORECAST AREA BY EARLY THIS AFTERNOON...SO EXPANDED CLOUD COVER. THE LATEST NAM12/SREF/GFS/HRRR INDICATED THE NORTHERN AND SE FORECAST AREA COULD GET ISOLATED/SCATTERED SHOWERS AND STORMS THIS AFTERNOON AND EARLY EVENING...SO INCREASED AND EXPANDED COVERAGE OF PCPN CHANCES. THERE MAY BE A THREAT FOR ISOLATED STRONG STORMS IN THE COOK COUNTY AREA OF THE ARROWHEAD THIS AFTERNOON AND EARLY EVENING. THE NAM12 AND GFS SOUNDINGS FOR THE HIGHER TERRAIN OF THE ARROWHEAD INDICATE MUCAPE COULD BUILD TO AROUND 1000 J/KG BY THE MIDDLE OF THE AFTERNOON...AND THERE WOULD BE ABOUT 30 TO 35 KNOTS OF DEEP LAYER WIND SHEAR. ALSO...FREEZING LEVELS WILL BE RELATIVELY LOW IN THE HIGHER TERRAIN...ABOUT 9000 FT. THEREFORE...WOULD NOT BE SURPRISED BY ISOLATED STORMS CAPABLE OF PRODUCING SMALL HAIL AND GUSTY WINDS. UPDATE ISSUED AT 612 AM CDT MON AUG 10 2015 PATCHY FOG WAS DOTTING THE LANDSCAPE...BUT SHOULD BURN OFF QUICKLY. STILL ANTICIPATING SHOWERS AND STORMS WITH THE SHORTWAVE TROF SET TO CLIP THE ARROWHEAD TODAY. LOWERED THE POPS IN NW WI A BIT AS THE TROF STAYS A BIT FURTHER EAST. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 309 AM CDT MON AUG 10 2015 A SFC LOW CENTER WAS MOVING THROUGH EASTERN LAKE SUPERIOR AT 07Z WITH ITS ASSOCIATED FRONTAL BOUNDARY MOVING THROUGH NW WI. AREAS OF FOG HAD FORMED ONCE AGAIN ACROSS MUCH OF THE REGION. EXPECT THE FOG TO LINGER UNTIL 14Z. AS THE FRONT EXITS NW WI...HIGH PRESSURE BUILDS ACROSS THE AREA. HOWEVER...AN UPPER LEVEL SHORTWAVE TROF WILL REACH THE INTERNATIONAL BORDER BY 18Z AND PROCEED ACROSS THE ARROWHEAD AND OVER LAKE SUPERIOR. SCATTERED SHOWERS AND THUNDERSTORMS WILL BEGIN TO AFFECT THE ARROWHEAD WWD TO NEAR CDD AT 15Z. STORMS WILL PERCOLATE OVER THE ARROWHEAD THROUGH THE AFTERNOON WITH SOME STORM DEVELOPMENT IN NW WI IN THE AFTERNOON. THE SHORTWAVE TROF REACHES NORTHERN LOWER MICHIGAN BY 06Z TUESDAY. ONE MORE IMPULSE WILL CLIP THE ARROWHEAD BEHIND THE TROF AND RESULT IN SOME ISOLD SHOWERS FROM CKC TO GRAND PORTAGE. THIS ACTIVITY WILL DIMINISH BY 03Z AS FORCING MOVES EAST AND SFC RIDGING COVERS THE AREA. THE SFC RIDGING PERSISTS THROUGH TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 309 AM CDT MON AUG 10 2015 WARMER MID-WEEK WITH HIGHS IN THE LOW TO MID 80S ACROSS THE REGION...THEN NOT AS HOT BUT STILL ABOVE NORMAL THROUGH SATURDAY WITH HIGHS IN THE UPPER 70S TO LOW 80S. TWO MAIN PERIODS OF POSSIBLE PRECIPITATION...ONE ON WEDNESDAY NIGHT INTO THURSDAY AS A COLD FRONT SWEEPS THROUGH FROM NORTHWEST TO SOUTHEAST...THEN AGAIN SATURDAY NIGHT INTO SUNDAY AS ANOTHER COLD FRONT MOVES THROUGH. SOME UNCERTAINTY EXISTS WITH THE TIMING OF THE LATE WEEKEND SYSTEM...BUT IN GENERAL HAVE AN AVERAGE LEVEL OF CONFIDENCE FOR THE FORECAST. ON THE SYNOPTIC SCALE A UPPER LEVEL RIDGE CENTERED OVER THE HIGH PLAINS WILL GRADUALLY DRIFT WESTWARD TOWARDS THE FOUR CORNERS THROUGH THE REST OF THE WORK WEEK...LEADING TO NORTHWEST FLOW ALOFT LOCALLY. AHEAD OF A COLD FRONT/MID LEVEL DISTURBANCE SOUTHWESTERLY WINDS COULD BECOME BREEZY WITH STRONG WARM AIR ADVECTION LEADING TO PROBABLY THE WARMEST DAY OF THE FORECAST PERIOD. THERE IS A WEAK MID- LEVEL IMPULSES IN THE NORTHWESTERLY FLOW WITH AN ASSOCIATED SFC LOW THAT MOVES ACROSS NORTHWEST MINNESOTA INTO NORTHERN WISCONSIN LATE WEDNESDAY INTO THURSDAY. THIS WILL BE SUPPORTED BY A 60-80 KT UPPER LEVEL JET STREAK OVER THE UPPER MISSISSIPPI VALLEY...POSSIBLY PEAKING UP TO 100 KTS IN STRENGTH OVER CENTRAL MINNESOTA. MODEL SOUNDINGS DEPICT MODEST MID-LEVEL LAPSE RATES TO SUPPORT THUNDERSTORMS...AND THE STRONG WINDS ALOFT WILL RESULT IN 35-45 KTS DEEP LAYER SHEAR SUPPORTIVE OF POSSIBLY A FEW STRONG STORMS OVERNIGHT INTO THURSDAY. COVERAGE OF STORMS MAY BE LIMITED GIVEN ELEVATED NATURE AND DEPENDENCE ON UPSTREAM CONVECTION EVOLUTION...BUT IN GENERAL THIS PERIOD LOOKS GOOD FOR ISOLATED/SCATTERED STORMS. FRIDAY/SATURDAY A HIGH PRESSURE OVER SOUTHERN SASKATCHEWAN/MANITOBA DRIFTS INTO THE NORTHERN PLAINS THEN EAST ACROSS THE UPPER GREAT LAKES RESULTING IN SUNNY SKIES AND SEASONABLE TO JUST ABOVE NORMAL TEMPERATURES...UPPER 70S TO MID 80S. LATE SATURDAY INTO SUNDAY AN UPPER LOW ENTERING BRITISH COLUMBIA WILL ABSORB THE ENERGY FROM AN UPPER LOW OFF THE COAST OF THE PACIFIC NORTHWEST...DEEPENING INTO AN UPPER LOW/TROUGH AS IT CROSSES THE CANADIAN PRAIRIE. A SECONDARY SFC LOW/LEE TROUGH WILL DEVELOP OVER THE NORTHERN PLAINS ON SATURDAY ALONG A COLD FRONT EXTENDING FROM NEAR THE MAIN SFC LOW IN SOUTHERN CANADA INTO THE CENTRAL PLAINS. GUIDANCE IS IN FAIRLY REMARKABLE AGREEMENT FOR THIS TIME RANGE...WITH ECMWF/GFS/GEM DEPICTING A STRONG COLD FRONT IN THE EASTERN DAKOTAS/FAR WESTERN MINNESOTA AROUND 00Z SUNDAY /SAT NIGHT/ PROGRESSING EASTWARD...THOUGH FROM THERE MODEL SOLUTIONS DIVERGE. PRECIP CHANCES LOOK FAIRLY HIGH REGARDLESS OF SPECIFICS. MOISTURE CONTENT WITH THIS SYSTEM MAY BE ON THE HIGH SIDE GIVEN THE PACIFIC INFLUENCES. COOLER TEMPERATURES EXPECTED IN WAKE OF THIS FRONT WITH HIGHS NEAR OR SLIGHTLY BELOW SEASONABLE...IN THE LOW TO MID 70S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 647 AM CDT MON AUG 10 2015 WITH MINOR EXCEPTIONS...VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD THROUGHOUT THE REGION. PATCHY FOG RESULTING IN IFR CONDITIONS AT HYR THIS MORNING BUT WILL LIFT AND CLEAR OUT OVER THE NEXT HOUR. OTHERWISE EXPECTING SCATTERED/BROKEN 4-5KFT CLOUD DECK TO DEVELOP THIS AFTERNOON WITH AN ISOLATED SHOWER POSSIBLE AT HIB AND INL. OVERNIGHT TONIGHT SKIES GRADUALLY CLEAR OUT WITH PATCHY FOG AGAIN POSSIBLE...FELT MOST CONFIDENT FOR HIB SO INCLUDED A MENTION OF MVFR VISIBILITY LATE TONIGHT. OTHER SITES MAY SEE FOG BUT CHANCES SEEM TOO LOW TO INCLUDE IN THIS TAF ISSUANCE GIVEN THE COVERAGE OF FOG LAST NIGHT WAS A BIT LESS THAN ORIGINALLY ANTICIPATED. WINDS LIGHT OUT OF THE NORTH- NORTHWEST...WITH A FEW GUSTS TO AROUND 17 KTS POSSIBLE. && .PRELIMINARY POINT TEMPS/POPS... DLH 77 57 75 59 / 20 10 0 10 INL 74 52 77 56 / 20 10 0 10 BRD 79 55 80 56 / 0 0 0 0 HYR 77 55 76 53 / 20 20 0 10 ASX 76 57 73 54 / 20 20 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. LS...NONE. && $$ UPDATE...GROCHOCINSKI SHORT TERM...GSF LONG TERM...JJM AVIATION...JJM
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
940 AM CDT AUG 10 2015 .UPDATE...LATEST SATELLITE IMAGERY WAS SHOWING A WEAKENING MCS ASSOCIATED WITH A SHORT WAVE OVER THE MIDSOUTH. IT HAD SENT A DRY OUTFLOW BOUNDARY INTO OUR NORTHERN COUNTIES AS OF MID MORNING. THE BOUNDARY WILL BE MOVING INTO A CAPPED REGION WITH THE STRONG SUBTROPICAL RIDGE CENTERED OVER THE WESTERN ARKLATEX. IT SHOULD LIMIT THE STRONG THUNDERSTORM POTENTIAL FOR THIS AFTERNOON. WILL MONITOR THE BOUNDARY AS IT MOVES THROUGH THE REGION FOR ANY GOOD CU FIELD CONVERGENCE ON SATELLITE. IT WILL BE ANOTHER HOT DAY. THE BLOWOFF FROM THE MCS MAY HAMPER TEMPS SLIGHTLY IN THE NORTHEAST...BUT WILL HOLD ONTO THE UPPER 90S IN THAT AREA. TEMPS HAVE ALREADY HIT 90 AT JAN AS OF 920 AM. CURRENT POPS LOOK TO BE ON TRACK. THE HRRR HIRES DEVELOPS SOME DECENT CONVECTIVE COVERAGE FOR THIS AFTERNOON EAST OF MS RIVER WITH THE OUTFLOW BOUNDARY MOVING THROUGH. SO WITH THAT IN MIND WILL MAKE NO CHANGES TO CURRENT FORECAST TEMPS AND POPS./17/ && .AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH THE DAY AT MOST TERMINALS. ISOLATED TO SCATTERED STORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON, MOST LIKELY TO BE AROUND GTR, JAN/HKS, MEI, AND HBG/PIB THROUGH EARLY EVENING. BRIEF CIG/VISBY REDUCTIONS DUE TO +RA AND GUSTY WINDS ARE POSSIBLE WITH THE STORMS. LATER TONIGHT, A SHORT PERIOD OF PATCHY FOG IS POSSIBLE AROUND DAYBREAK, MAINLY AT SITES ALONG AND SOUTH OF I-20. /DL/ && ./PREVIOUS DISCUSSION...529 AM CDT MON AUG 10 2015 .DISCUSSION... TODAY THROUGH TUESDAY NIGHT... A STRONG SUBTROPICAL RIDGE CENTERED OVER THE ARKLATEX REGION... SUPPORTS ANOTHER DAY OF EXCESSIVE HEAT ACROSS THE ARKLAMISS WITH H850 TEMPERATURES EXPECTED TO PEAK AROUND 25 DEG C...BUT MESOSCALE INFLUENCES RAISE UNCERTAINTY REGARDING THE EXACT DURATION/INTENSITY OF TODAY`S HEAT EVENT. A SIGNIFICANT SHORTWAVE TROUGH MOVING THROUGH THE MID MS VALLEY REGION HAS INITIATED A MESOSCALE CONVECTIVE SYSTEM THAT IS MOVING SOUTHEAST INTO NE AR/WRN TN. EXTRAPOLATION OF THE OUTFLOW BOUNDARY ASSOCIATED WITH THIS MCS BRINGS IT TO THE HWY 82 CORRIDOR LATE THIS MORNING...AND RECENT RUNS OF THE HRRR HAVE A GOOD HANDLE ON THIS ASSUMING CURRENT TIMING IS MAINTAINED. PER HRRR GUIDANCE...THE DENSITY OF THE OUTFLOW WILL BE SUFFICIENT FOR IT TO CONTINUE MOVING SOUTHWARD THROUGH THE ENTIRE AREA BY LATE AFTN...HOWEVER IT WILL BE MOVING INTO AND AIRMASS THAT IS SOMEWHAT CAPPED AND THIS COULD LIMIT OVERALL THUNDERSTORM POTENTIAL. STORM DEVELOPMENT AND INTENSITY WILL BE GOVERNED BY HOW MUCH DESTABILIZATION CAN TAKE PLACE PRECEDING THE FAST-MOVING BOUNDARY. THE NEW SPC SSEO IS HINTING AT A GREATER THREAT FOR STORMS OVER EASTERN/SOUTHERN MS LATE THIS AFTN/EVNG...BUT THE TIMING COULD BE TOO SLOW. WILL BE MONITORING TRENDS TO POTENTIALLY ADD A LIMITED THREAT FOR SEVERE STORMS FOR THIS AFTN/EVNG...ESPECIALLY IF THE BOUNDARY SLOWS DOWN SOME. ASIDE FROM THE STORM POTENTIAL TODAY...THE BOUNDARY WILL ACT TO DISRUPT HEATING AND COULD HELP TO MITIGATE OVERALL HEAT STRESS IF THE AIRMASS IS UNABLE TO RECOVER AND HEAT BACK UP IN THE WAKE OF THE BOUNDARY. CURRENT INDICATIONS IN THE HRRR ARE THAT RE- HEATING SO TO SPEAK WILL TAKE PLACE OVER NORTH CENTRAL/NE MS...BUT LOCATIONS FARTHER SOUTH/WEST MAY SEE A PRE-MATURE ENDING TO THE DIURNAL TEMPERATURE TREND THAT COULD RESULT IN HIGH TEMPERATURES/HEAT INDICES THAT ARE A LITTLE LESS THAN PREVIOUSLY EXPECTED. THE FORECAST FOR TUESDAY LARGELY HINGES ON TODAY AND THIS EVENING`S CONVECTIVE EVOLUTION. IT SHOULD BE THE LAST DAY OF DANGEROUS HEAT IN THIS EPISODE WITH GREATEST CONFIDENCE FOR HIGHER HEAT INDICES MAINLY ALONG/S OF THE I-20 CORRIDOR. CONFIDENCE IS HIGH ENOUGH TO WARRANT ISSUANCE OF A HEAT ADVISORY...BUT THERE IS SOME MARGINAL POTENTIAL THAT AN EXCESSIVE HEAT WARNING COULD BECOME NECESSARY OVER PORTIONS OF NE LA/SW MS. CONCERNING STORM POTENTIAL...FOR NOW HAVE STUCK WITH THE IDEA THAT STORMS TODAY WILL LIMIT TUESDAY`S CONVECTIVE DEVELOPMENT TO MAINLY ERN/SRN MS AHEAD OF AN APPROACHING FRONT AND THE LEADING EDGE OF MUCH DRIER AIR. IT IS POSSIBLE THAT A MARGINAL THREAT FOR SEVERE STORMS WILL EXIST DEPENDING ON THE AMOUNT OF DESTABILIZATION. /EC/ WEDNESDAY THROUGH NEXT SUNDAY... UNFORTUNATELY THROUGHOUT THE CURRENT LONG TERM PORTION OF THE FORECAST...IT APPEARS THERE`S VERY LITTLE HOPE IN THE WAY OF GETTING SOME MUCH NEEDED RAINFALL OVER THE REGION. HOWEVER...THE "SILVER LINING" DURING THE PERIOD WILL BE FOUND IN GETTING SOME RELIEF FROM THE OPPRESSIVE HEAT THAT`S PLAGUED THE FORECAST AREA IN RECENT DAYS/WEEKS. THE FORECAST AREA WILL BECOME FIXED BETWEEN AN UPPER TROUGH OVER THE EAST COAST OF THE UNITED STATES AND THE STUBBORN UPPER RIDGE CENTERED NEAR THE FOUR CORNERS REGION. NORTHERLY FLOW ALOFT AND AT THE SURFACE THROUGH MUCH OF THE WEEK WILL ADVECT DRIER AIR INTO THE REGION. WHILE HIGHS TOP OUT IN THE LOW TO MIDDLE 90S...THE NOTICEABLY DRIER AIR WILL HELP TO MAKE FOR MORE TOLERABLE CONDITIONS EACH AFTERNOON...AS WELL AS OVERNIGHT AS LOWS FALL INTO THE 60S AND 70S. AS EXPECTED THROUGH...DEW POINTS WILL MODERATE UP SLIGHTLY OVER THE WEEKEND...AND THE CHANCES OF AT LEAST SOME ISOLATED CONVECTION RETURNING TO THE FORECAST SATURDAY AND SUNDAY. /19/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 102 77 99 75 / 30 31 32 21 MERIDIAN 100 73 94 74 / 23 42 43 29 VICKSBURG 103 77 99 73 / 22 18 23 15 HATTIESBURG 100 76 98 76 / 20 17 49 42 NATCHEZ 101 78 98 75 / 27 16 33 20 GREENVILLE 101 77 96 73 / 12 18 7 7 GREENWOOD 100 75 95 72 / 24 28 15 8 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR MSZ018- 019-025>066-072>074. HEAT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT TUESDAY FOR MSZ040>043-047>066-072>074. LA...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR LAZ007>009-015-016-023>026. HEAT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT TUESDAY FOR LAZ007>009-015-016-023>026. AR...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR ARZ074- 075. && $$ EC/19/
AREA FORECAST DISCUSSION
NWS JACKSON MS
529 AM CDT MON AUG 10 2015 .DISCUSSION... TODAY THROUGH TUESDAY NIGHT... A STRONG SUBTROPICAL RIDGE CENTERED OVER THE ARKLATEX REGION... SUPPORTS ANOTHER DAY OF EXCESSIVE HEAT ACROSS THE ARKLAMISS WITH H850 TEMPERATURES EXPECTED TO PEAK AROUND 25 DEG C...BUT MESOSCALE INFLUENCES RAISE UNCERTAINTY REGARDING THE EXACT DURATION/INTENSITY OF TODAY`S HEAT EVENT. A SIGNIFICANT SHORTWAVE TROUGH MOVING THROUGH THE MID MS VALLEY REGION HAS INITIATED A MESOSCALE CONVECTIVE SYSTEM THAT IS MOVING SOUTHEAST INTO NE AR/WRN TN. EXTRAPOLATION OF THE OUTFLOW BOUNDARY ASSOCIATED WITH THIS MCS BRINGS IT TO THE HWY 82 CORRIDOR LATE THIS MORNING...AND RECENT RUNS OF THE HRRR HAVE A GOOD HANDLE ON THIS ASSUMING CURRENT TIMING IS MAINTAINED. PER HRRR GUIDANCE...THE DENSITY OF THE OUTFLOW WILL BE SUFFICIENT FOR IT TO CONTINUE MOVING SOUTHWARD THROUGH THE ENTIRE AREA BY LATE AFTN...HOWEVER IT WILL BE MOVING INTO AND AIRMASS THAT IS SOMEWHAT CAPPED AND THIS COULD LIMIT OVERALL THUNDERSTORM POTENTIAL. STORM DEVELOPMENT AND INTENSITY WILL BE GOVERNED BY HOW MUCH DESTABILIZATION CAN TAKE PLACE PRECEDING THE FAST-MOVING BOUNDARY. THE NEW SPC SSEO IS HINTING AT A GREATER THREAT FOR STORMS OVER EASTERN/SOUTHERN MS LATE THIS AFTN/EVNG...BUT THE TIMING COULD BE TOO SLOW. WILL BE MONITORING TRENDS TO POTENTIALLY ADD A LIMITED THREAT FOR SEVERE STORMS FOR THIS AFTN/EVNG...ESPECIALLY IF THE BOUNDARY SLOWS DOWN SOME. ASIDE FROM THE STORM POTENTIAL TODAY...THE BOUNDARY WILL ACT TO DISRUPT HEATING AND COULD HELP TO MITIGATE OVERALL HEAT STRESS IF THE AIRMASS IS UNABLE TO RECOVER AND HEAT BACK UP IN THE WAKE OF THE BOUNDARY. CURRENT INDICATIONS IN THE HRRR ARE THAT RE- HEATING SO TO SPEAK WILL TAKE PLACE OVER NORTH CENTRAL/NE MS...BUT LOCATIONS FARTHER SOUTH/WEST MAY SEE A PRE-MATURE ENDING TO THE DIURNAL TEMPERATURE TREND THAT COULD RESULT IN HIGH TEMPERATURES/HEAT INDICES THAT ARE A LITTLE LESS THAN PREVIOUSLY EXPECTED. THE FORECAST FOR TUESDAY LARGELY HINGES ON TODAY AND THIS EVENING`S CONVECTIVE EVOLUTION. IT SHOULD BE THE LAST DAY OF DANGEROUS HEAT IN THIS EPISODE WITH GREATEST CONFIDENCE FOR HIGHER HEAT INDICES MAINLY ALONG/S OF THE I-20 CORRIDOR. CONFIDENCE IS HIGH ENOUGH TO WARRANT ISSUANCE OF A HEAT ADVISORY...BUT THERE IS SOME MARGINAL POTENTIAL THAT AN EXCESSIVE HEAT WARNING COULD BECOME NECESSARY OVER PORTIONS OF NE LA/SW MS. CONCERNING STORM POTENTIAL...FOR NOW HAVE STUCK WITH THE IDEA THAT STORMS TODAY WILL LIMIT TUESDAY`S CONVECTIVE DEVELOPMENT TO MAINLY ERN/SRN MS AHEAD OF AN APPROACHING FRONT AND THE LEADING EDGE OF MUCH DRIER AIR. IT IS POSSIBLE THAT A MARGINAL THREAT FOR SEVERE STORMS WILL EXIST DEPENDING ON THE AMOUNT OF DESTABILIZATION. /EC/ WEDNESDAY THROUGH NEXT SUNDAY... UNFORTUNATELY THROUGHOUT THE CURRENT LONG TERM PORTION OF THE FORECAST...IT APPEARS THERE`S VERY LITTLE HOPE IN THE WAY OF GETTING SOME MUCH NEEDED RAINFALL OVER THE REGION. HOWEVER...THE "SILVER LINING" DURING THE PERIOD WILL BE FOUND IN GETTING SOME RELIEF FROM THE OPPRESSIVE HEAT THAT`S PLAGUED THE FORECAST AREA IN RECENT DAYS/WEEKS. THE FORECAST AREA WILL BECOME FIXED BETWEEN AN UPPER TROUGH OVER THE EAST COAST OF THE UNITED STATES AND THE STUBBORN UPPER RIDGE CENTERED NEAR THE FOUR CORNERS REGION. NORTHERLY FLOW ALOFT AND AT THE SURFACE THROUGH MUCH OF THE WEEK WILL ADVECT DRIER AIR INTO THE REGION. WHILE HIGHS TOP OUT IN THE LOW TO MIDDLE 90S...THE NOTICEABLY DRIER AIR WILL HELP TO MAKE FOR MORE TOLERABLE CONDITIONS EACH AFTERNOON...AS WELL AS OVERNIGHT AS LOWS FALL INTO THE 60S AND 70S. AS EXPECTED THROUGH...DEW POINTS WILL MODERATE UP SLIGHTLY OVER THE WEEKEND...AND THE CHANCES OF AT LEAST SOME ISOLATED CONVECTION RETURNING TO THE FORECAST SATURDAY AND SUNDAY. /19/ && .AVIATION...VFR CONDITIONS WILL BE THE GENERAL RULE TODAY THROUGH TONIGHT. THE EXCEPTIONS WILL BE A MIX OF HAZE/MIST EARLY THIS MORNING THAT MAY RESULT IN OCCASIONAL MVFR VSBYS...AND ANY TSRA ACTIVITY THAT DEVELOPS IN ASSOCIATION WITH AN APPROACHING OUTFLOW BOUNDARY...ESPECIALLY IN THE GTR AREA. CURRENT EXTRAPOLATION BRINGS THE BOUNDARY TO VICINITY OF GTR BY AROUND 15Z...BUT THINKING IT WILL SLOW DOWN SOME AND DELAY TIMING TO MORE OF THE AFTN/EVNG. /EC && .PRELIMINARY POINT TEMPS/POPS... JACKSON 102 77 99 75 / 30 31 32 21 MERIDIAN 100 73 94 74 / 23 42 43 29 VICKSBURG 103 77 99 73 / 22 18 23 15 HATTIESBURG 100 76 98 76 / 20 17 49 42 NATCHEZ 101 78 98 75 / 27 16 33 20 GREENVILLE 101 77 96 73 / 12 18 7 7 GREENWOOD 100 75 95 72 / 24 28 15 8 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR MSZ018- 019-025>066-072>074. HEAT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT TUESDAY FOR MSZ040>043-047>066-072>074. LA...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR LAZ007>009-015-016-023>026. HEAT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT TUESDAY FOR LAZ007>009-015-016-023>026. AR...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR ARZ074- 075. && $$ EC/19/
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
615 AM CDT MON AUG 10 2015 .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 332 AM CDT MON AUG 10 2015 SHORT RANGE GUIDANCE SEEMS TO BE IN GOOD AGREEMENT WITH CURRENT RADAR TRENDS IN CONTINUING TO PUSH THE BAND OF CONVECTION SOUTH OF OUR CWFA BY 12Z. UPSTREAM DEVELOPMENT OVER SOUTHWEST MISSOURI LOOKS LIKE IT SHOULD STAY OUT OF OUR AREA...BUT WE MAY STILL GET CLIPPED SO HAVE KEPT MID-HIGH CHANCE POPS GOING PAST 12Z ACROSS SOUTHERN ZONES. FURTHER NORTH, SHORT RANGE GUIDANCE HAS CONSISTENTLY BEEN WEAKENING THE CONVECTION NOW MOVING INTO NORTHWEST MISSOURI OUT OF IOWA, AND CURRENT RADAR TRENDS SUPPORT THIS AS WELL. THAT BEING SAID, ISOLATED TO WIDELY SCATTERED STORMS WILL CONTINUE TO BE POSSIBLE ACROSS THROUGH THE MORNING FROM I-70 NORTHWARD. THE ACTUAL SYNOPTIC COLD FRONT IS DIFFICULT TO FIND AT THIS TIME, BUT LOOKS LIKE IT SHOULD PUSH THROUGH THE AREA FROM MID MORNING THROUGH THE AFTERNOON. RAP HAS THE 850MB FLOW TURNING SHARPLY TO THE NORTH- NORTHWEST WITH DECENT COLD ADVECTION (FOR AUGUST) BEHIND IT. SHOULD STILL BE ENOUGH INSTABILITY TO CONTINUE A CHANCE OF THUNDERSTORMS THROUGH THE AFTERNOON INTO EARLY EVENING. STUCK PRETTY CLOSE TO GUIDANCE FOR TEMPERATURES TODAY...THOUGH HIGHS WILL BE DIFFICULT TO PIN DOWN DUE TO AFTERNOON CONVECTION. CARNEY .LONG TERM: (TONIGHT THROUGH SUNDAY) ISSUED AT 345 AM CDT MON AUG 10 2015 EXPECT A FEW SHOWERS OR THUNDERSTORMS TO LINGER INTO EARLY THIS EVENING, BUT SHOULD BE GONE BEFORE MIDNIGHT. DRIER AIR IS FORECAST TO BUILD ACROSS THE AREA BEHIND THE FRONT TONIGHT AND TUESAY...AND LAST AT LEAST THROUGH THE END OF THE WEEK WITH DEWPOINT TEMPERATURES DROPPING INTO THE 60S. A HIGH AMPLITUDE UPPER LEVEL PATTERN LOCKS THE DRY LOW LEVEL RIDGE OVER THE MISSISSIPPI VALLEY, SO PRECIPITATION CHANCES ARE VIRTUALLY NIL. THIS SHOULD MAKE FOR RELATIVELY COMFORTABLE WEATHER FOR WHAT ARE TYPICALLY THE DOG-DAYS OF SUMMER WITH HIGHS NEAR OR A FEW DEGREES BELOW NORMAL IN THE MID TO UPPER 80S AND LOWS WELL BELOW NORMAL IN THE 60S. CARNEY && .AVIATION: (FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 611 AM CDT MON AUG 10 2015 MAIN AREA OF CONVECTION REMAINS SOUTH OF TERMINALS FROM NEAR LAKE OF THE OZARKS TO BOOTHEEL OF MISSOURI. COLD FRONT JUST NOW CROSSING MISSOURI/IOWA STATE LINE AND WILL CONTINUE TO MOVE SOUTH ACROSS THE AREA THIS MORNING. COULD SEE SOME SHOWERS AND STORMS DEVELOP ALONG THIS BOUNDARY TODAY...BUT COVERAGE IS EXPECTED TO BE ISOLATED TO WIDELY SCATTERED AND THEREFORE IS LEFT OUT OF TERMINAL FORECAST AT THIS TIME. LIGHT SOUTH WIND WILL BECOME NORTHERLY BEHIND THE FRONT. SOME IFR FOG AND STRATUS EARLY THIS MORNING SHOULD IMPROVE THROUGH THE MORNING WITH MOSTLY CLEAR CONDITIONS EXPECTED THIS EVENING AS HIGH PRESSURE MOVES INTO THE REGION. SPECIFICS FOR KSTL: IFR STRATUS NEARBY AT KSUS AND KCPS AND MAY IMPACT TERMINAL EARLY THIS MORNING. OTHERWISE...WIND SHIFT WITH COLD FRONT EXPECTED AROUND 15Z. VFR CONDITIONS EXPECTED THIS AFTERNOON WITH THE POTENTIAL OF A SHOWER OR STORM. CHANCES ARE TOO LOW TO INCLUDE IN FORECAST AT THIS TIME. CVKING && .PRELIMINARY POINT TEMPS/POPS: SAINT LOUIS 88 72 86 68 / 40 30 10 5 QUINCY 83 64 84 62 / 40 30 5 0 COLUMBIA 87 67 85 63 / 40 30 5 0 JEFFERSON CITY 89 68 86 63 / 40 30 5 0 SALEM 86 70 84 63 / 40 30 10 5 FARMINGTON 86 69 84 61 / 40 30 10 0 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EDT MON AUG 10 2015 .SYNOPSIS...A WARM FRONT TO OUR SOUTHWEST THIS MORNING WILL LIFT NORTH ACROSS THE AREA TODAY. A COLD FRONT WILL SWEEP THROUGH THE REGION TUESDAY AND TUESDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA ON WEDNESDAY AND PERSIST THROUGH THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1020 AM MONDAY... CURRENT FORECAST IS IN GOOD SHAPE. MAIN CHANGES WERE TO EXPAND IN TIME AND AREA THE BAND OF PATCHY SHOWERS CURRENTLY TRACKING THROUGH THE CWA... DRIVEN BY WEAK MOIST ISENTROPIC UPGLIDE IN THE LOW LEVELS AND A WEAK MID LEVEL WAVE... AND TO DELAY AFTERNOON CONVECTION IN THE WEST. HIGH-PW AIR (1.8-2.0") PERSISTS OVER CENTRAL NC WITH CONSIDERABLE MID AND HIGH DEBRIS CLOUDINESS FROM UPSTREAM MCS ACTION OVERSPREADING THE AREA FROM THE NW... AND THIS SHOULD SOMEWHAT CURB THE POTENTIAL FOR INSTABILITY THIS AFTERNOON. EXTRAPOLATION WOULD FAVOR ANY MCVS GENERATED BY LAST NIGHT`S THE CONVECTIVE COMPLEXES ACROSS SRN KS/MO/IL INTO WRN KY/TN LIKELY TRACKING WELL TO OUR SW... AND THIS TREND IS INDICATED BY THE NSSL WRF AND NCAR ENSEMBLE NEIGHBORHOOD PROBABILITIES. THESE MODEL PACKAGES ALSO SUGGEST THAT THE CHANCE FOR DEEP CONVECTION EAST OF HIGHWAY 1 THIS AFTERNOON INTO TONIGHT IS QUITE LOW... AND THE HRRR ALSO DEPICTS LITTLE TO NO COVERAGE OVER ALL BUT THE FAR WRN CWA AFTERNOON THROUGH AT LEAST 23Z. AFTER SLOWLY TRENDING THE COVERAGE OF SHOWERS DOWN THIS MORNING INTO EARLY AFTERNOON AS THEY TREND EASTWARD WITH WANING UPGLIDE... HAVE REDUCED CONVECTION CHANCES TO SLIGHT OR NIL IN THE EAST THIS AFTERNOON... AND HAVE CUT BACK COVERAGE IN THE WRN CWA A BIT AS WELL. GIVEN THE GENERALLY MOSTLY CLOUDY SKIES TODAY... HAVE CUT A COUPLE OF DEGREES OFF HIGHS... NOW RANGING FROM 84 TO 90. -GIH EARLIER DISCUSSION AS OF 255 AM: LATEST SURFACE ANALYSIS SHOWS WEAK HIGH PRESSURE EXTENDING INTO EASTERN VA AND NC. MEANWHILE A WARM FRONT EXTENDING FROM NEAR NASHVILLE TN SOUTHEAST TO NEAR SAVANNAH GA WAS BEGINNING TO SLOWLY LIFT NORTHWARD...LIKELY LIFTING THROUGH CENTRAL NC THIS AFTERNOON AND EVENING. FURTHER ALOFT...A RATHER WEAK DIFFLUENT NORTHWEST FLOW ALOFT WAS EXPECTED TO STRENGTHEN AND GRADUALLY BACK AND BECOME SOUTHWESTERLY BY LATE TONIGHT AS AN UPPER TROUGH DROPS INTO THE GREAT LAKES REGION. REGIONAL RADAR IMAGERY SHOWS SCT SHOWERS SLOWLY DEVELOPING AND EXPANDING ACROSS THE YADKIN VALLEY AND THE WESTERN PIEDMONT OF VA/NC/SC. THIS PRECIPITATION APPEARS TO BE ASSOCIATED WITH SOME ISENTROPIC UPGLIDE NEAR THE 305K SURFACE ENHANCED BY A WEAK SHORT WAVE ALOFT AND REMNANTS OF AN UPSTREAM MCS. NWP GUIDANCE SUGGESTS THAT THESE SHOWERS MAY BECOME MORE NUMEROUS AS THEY MOVE INTO THE WESTERN PIEDMONT TOWARD DAYBREAK. THE PRECIPITATION SHOULD BEGIN TO DIMINISH LATE THIS MORNING BEFORE REACHING THE COASTAL PLAIN. MUCH OF THE DAY TODAY SHOULD FEATURE A FAIR AMOUNT OF CLOUDINESS BUT MAINLY DRY CONDITIONS ACROSS CENTRAL NC. WITH LITTLE FORCING FOR ASCENT AND WITH ONLY WEAK INSTABILITY PRESENT THIS AFTERNOON AND FAIRLY MEAGER MID LEVEL LAPSE RATES...CONVECTIVE COVERAGE SHOULD BE RATHER LIMITED. THE ENVIRONMENT FOR CONVECTION BECOMES A LITTLE BIT MORE FAVORABLE THIS EVENING AND OVERNIGHT ACROSS THE WESTERN PIEDMONT AND TRIAD AREA AS LARGER SCALE FORCING APPROACHES AND MID LEVEL LAPSE RATE ACCORDINGLY INCREASE. STILL...CONVECTION ALLOWING MODELS HAVE TRENDED NOTICEABLY LESS ACTIVE FOR THIS AFTERNOON AND TONIGHT WITH NOCTURNAL CONVECTION NOW APPEARING MORE FOCUSED ACROSS VA/WV. HIGHS TODAY WILL BE COMPLICATED BY THE AMOUNT OF SUNSHINE AND WITH A TREND TOWARD LESS PRECIPITATION AND PERHAPS THINNER CLOUDS HAVE ADJUSTED MAXES UP EVER-SO-SLIGHTLY...HIGHS SHOULD RANGE SHOULD RANGE FROM 84 TO 91. LOWS TONIGHT WILL BE MODERATED BY A GOOD DEAL OF CLOUD COVER...LOWS SHOULD RANGE BETWEEN 69 AND 74 DEGREES. -BLAES && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 320 AM MONDAY... A STRENGTHENING UPPER TROUGH WILL MOVE ACROSS THE GREAT LAKES AND NORTHEAST DURING THE PERIOD WITH THE MAIN TROUGH AXIS SHIFTING ACROSS CENTRAL NC TOWARD DAYBREAK WEDNESDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS THE APPALACHIANS TUESDAY AFTERNOON AND THROUGH CENTRAL NC TUESDAY NIGHT...REACHING THE COAST TOWARD WEDNESDAY MORNING. SCATTERED CONVECTION IS EXPECTED AHEAD OF THE FRONT TUESDAY MORNING AND EARLY AFTERNOON. AS NOTED IN THE PREVIOUS DISCUSSION...THIS MAY PLAY A ROLE IN SUBSEQUENT CONVECTION TUESDAY AFTERNOON AND EVENING. WITH THE UPPER TROUGH CONTAINING MULTIPLE VORTICITY CENTERS...EXPECT SHOWERS AND THUNDERSTORMS TO MOVE ACROSS CENTRAL NC IN MULTIPLE CLUSTER OR BANDS THROUGHOUT THE AFTERNOON AS OPPOSED TO ONE WELL ORGANIZED LINE. THE CLOUDS AND PRECIPITATION WITH THESE CLUSTERS SHOULD RETARD INSTABILITY A BIT. SPC HAS CENTRAL NC OUTLOOKED WITH A MARGINAL THREAT OF SEVERE STORMS WHICH SEEMS REASONABLE GIVEN THE STRONGER DEEP LAYER FLOW AND BULK SHEAR VALUES OF 20-25 KTS SUGGESTING SOME STORM ORGANIZATION POSSIBLE. CAPE VALUES SHOULD RANGE FROM WEAK TO LOW END MODERATE WITH MLCAPE VALUES CLIMBING TO THE 750-1250 J/KG RANGE. THIS ENVIRONMENT WOULD SUPPORT A MULTICELLULAR/LINE SEGMENT CONVECTIVE MODE WITH A FEW STRONG STORMS AND POSSIBLY A SEVERE THUNDERSTORMS WITH DAMAGING WINDS THE MOST LIKELY THREAT. WITH A LINGERING SHORT WAVE TROUGH LIKELY TO MOVE ACROSS CENTRAL NC LATE TUESDAY EVENING...ANOTHER ROUND OF STORMS IS POSSIBLE WITH THIS FEATURE AND THE ASSOCIATED COLD FRONT. THE FRONT SHOULD EXIT THE RAH CWA BETWEEN 06-12Z AND BRING THE PRECIPITATION TO AN END. HIGHS IN THE 86 TO 91 RANGE WITH LOWS TUESDAY NIGHT IN THE 65 TO 73 RANGE. -BLAES && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 255 AM MONDAY... WEDNESDAY THROUGH FRIDAY... UPPER AIR PATTERN WILL BE DOMINATED BY A STRONG...AMPLIFIED RIDGE ALONG THE SPINE OF THE ROCKIES...AND A L/W TROUGH ALONG THE EASTERN SEABOARD. THIS TROUGH IS AT ITS MOST AMPLIFIED/DEEPEST AT MID WEEK THEN WEAKENS/BROADENS BY THE END OF THE WEEK. THIS SET-UP WILL SPREAD A DRIER STABLE AIR MASS INTO CENTRAL NC ON WEDNESDAY WHICH SHOULD LINGER THROUGH THE REMAINDER OF THE WORK WEEK AS AN AREA OF HIGH PRESSURE AT THE SURFACE BUILDS INTO THEN SETTLES OVERHEAD BY FRIDAY. ASIDE FROM A SLIGHT CHANCE OF A SHOWER EARLY WEDNESDAY OVER THE SE COUNTIES AS A COLD FRONT EXITS THE REGION...EXPECT DRY WEATHER WEDNESDAY THROUGH FRIDAY...AND TEMPERATURES AVERAGING FAIRLY CLOSE TO NORMAL FOR MID AUGUST. ONE THING THAT WILL BE LACKING WILL BE THE TYPICAL LATE SUMMER HUMIDITY AS AFTERNOON DEWPOINTS WILL DROP INTO THE 50S-LOWER 60S EACH AFTERNOON...ESPECIALLY ON THURSDAY AND FRIDAY. THIS WILL LEAD TO FAIRLY COMFORTABLE CONDITIONS FOR MID-AUGUST. FOR SATURDAY THROUGH SUNDAY...THE UPPER RIDGE BECOMES ORIENTATED SW- NE FROM THE DESERT SW INTO THE GREAT LAKES WHILE THE L/W TROUGH MAINTAINS A PRESENCE ALONG THE EASTERN SEABOARD. THE SFC HIGH WEAKENS WITH TIME BUT CONTINUES TO INFLUENCE THE SENSIBLE WEATHER OVER CENTRAL NC AS THE LOW LEVEL FLOW WILL MAINTAIN A FAIRLY MILD AIR MASS FOR THIS TIME OF YEAR. ENOUGH MOISTURE MAY CREEP BACK INTO SECTIONS OF OUR COASTAL PLAIN AND SANDHILL COUNTIES BY SUNDAY TO SPARK AN ISOLATED SHOWER OR STORM IN THE AFTERNOON. THE ATMOSPHERE WILL UNDERGO SLIGHT MODIFICATION...LEADING TO TEMPS SLIGHTLY ABOVE NORMAL BY SUNDAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 730 AM MONDAY... VFR CONDITIONS ARE EXPECTED FOR MUCH OF THE TAF PERIOD ALTHOUGH A STRENGTHENING SOUTHWESTERLY FLOW WILL PROVIDE INCREASING MOISTURE AND CLOUDS ALONG WITH A CHANCE OF CONVECTION...MAINLY ACROSS THE WESTERN PIEDMONT. SCATTERED SHOWERS ACROSS THE WESTERN AND NORTHERN PIEDMONT NEAR THE KGSO/KINT TERMINALS WILL CONTINUE TO MOVE SOUTH AND EAST THIS MORNING BUT GRADUALLY WEAKEN AS THEY APPROACH THE NORTHEAST PIEDMONT INCLUDING KRDU TERMINAL. THESE SHOWERS MAY PRODUCE A BRIEF MVFR CIG/VSBY RESTRICTION. OTHERWISE...VFR CONDITIONS WITH LAYERS OF MID AND HIGH CLOUDS ARE EXPECTED THIS MORNING ALONG WITH A SOUTH WIND AROUND 10KTS OR LESS. INCREASING AND LOWERING VFR CLOUDS ARE EXPECTED THIS AFTERNOON AND EVENING WITH CEILINGS GENERALLY RANGING BETWEEN 4-10KFT. WINDS WILL STRENGTHEN FROM THE SOUTH AND SOUTHWEST AFTER A WARM FRONT MOVES THROUGH THE AREA WITH GUSTS UP TO 16KTS AT TIMES AT THE KINT/KGSO/KRDU TERMINALS. WHILE AN ISOLATED SHOWER CANT BE RULED OUT DURING THE LATE MORNING INTO THE MID AFTERNOON HOURS THE COVERAGE SHOULD BE LIMITED ENOUGH TO EXCLUDE FROM THE TAFS. DURING THE LATE AFTERNOON...SCT THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS WESTERN NC AND THEN MOVE EAST IMPACTING THE KINT/KGSO/KRDU TERMINALS BETWEEN 20-02Z WITH MVFR VSBY AND CIG RESTRICTIONS. THESE STORMS WILL PUSH EAST POTENTIALLY REACHING KFAY/KRWI TOWARD MIDNIGHT. GUIDANCE ALSO SUGGESTS THAT A LAYER OF IFR/MVFR STRATUS MAY DEVELOP TOWARD DAYBREAK AT THE KFAY/KRWI TERMINALS. LOOKING BEYOND 06Z TUE...THUNDERSTORMS WILL LIKELY PUSH EAST MONDAY NIGHT AND WEAKEN WITH A PERIOD OF ADVERSE AVIATION CONDITIONS POSSIBLE. ANOTHER PERIOD OF SHOWERS/THUNDERSTORMS WITH ADVERSE AVIATION CONDITIONS APPEARS TO BE A GOOD BET TUESDAY AND TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA. FAIR WEATHER WITH MAINLY VFR CONDITIONS ARE EXPECTED FROM WEDNESDAY INTO FRIDAY AS HIGH PRESSURE BUILDS INTO THE REGION. -BLAES && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLAES NEAR TERM...HARTFIELD/BLAES SHORT TERM...BLAES LONG TERM...WSS AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
834 AM CDT MON AUG 10 2015 .UPDATE... ISSUED AT 815 AM CDT MON AUG 10 2015 12Z BISMARCK SKEW-T SHOWS A CONVECTIVE TEMPERATURE OF 77F TODAY WHICH WILL BE REACHED BETWEEN 16Z-17Z/11AM-NOON CDT. EXPECTING SOME CUMULUS TO DEVELOP...HOWEVER TIME-HEIGHT CROSS SECTIONS SHOW LIMITED MOISTURE IN THE 850-700MB LAYER...WITH DRIER AIR ABOVE. LATEST WATER VAPOR IMAGERY LOOP REVEALS A SHORTWAVE/VORTICITY LOBE LOCATED IN FAR SOUTHEAST SASKATCHEWAN EXTENDING INTO WESTERN NORTH DAKOTA. THIS SHORTWAVE IS PICKED UP BY THE GFS AND IS FORECAST TO REACH THE JAMES RIVER VALLEY 21Z-00Z. 850MB-700MB LAPSE RATES FORECAST AT 9.5C/KM LATE THIS AFTERNOON IN CENTRAL NORTH DAKOTA. HI RESOLUTION MODELS HRRR/ARW WEST/NMM WEST INDICATE ISOLATED SHOWERS BETWEEN BISMARCK AND JAMESTOWN 21Z-00Z. THE PREVIOUS DISCUSSION MENTIONED THIS POTENTIAL. BUFKIT SOUNDINGS CURRENTLY MAINTAIN A SHALLOW POCKET OF MOISTURE REMAINING IN PLACE LATE THIS AFTERNOON WHEN THE MAX OMEGA/VERTICAL MOTION IN THE LOWEST LAYERS IS REACHED. WITH VERY MINIMAL AREAL COVERAGE AT THIS TIME...WILL KEEP THINGS DRY AND WATCH THE TRENDS AND ADJUST IF NEEDED LATER THIS MORNING. FORECAST REMAINS ON TRACK. UPDATE ISSUED AT 542 AM CDT MON AUG 10 2015 MADE A QUICK UPDATE TO ADD PATCHY FOG FROM HETTINGER...THOUGH WASHBURN...TO RUGBY AND ROLETTE. OBSERVATIONS THIS MORNING HAVE FAVORED THAT REGION FOR FOG...AND THIS ALSO LINES UP WITH THE LATEST ITERATIONS OF THE HRRR AND RAP13. A COUPLE ROGUE SHOWERS DEVELOPED OVERNIGHT IN PARTS OF LOGAN AND MCINTOSH COUNTIES...BUT THOSE HAVE DISSIPATED. THE REMAINDER OF THE FORECAST IS ON TRACK AND ONLY ADJUSTED TO CAPTURE THE LATEST OBSERVATIONS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 314 AM CDT MON AUG 10 2015 A QUIET START TO THE DAY IS EXPECTED WITH HIGH PRESSURE IN PLACE AT THE SURFACE ACROSS THE NORTHERN PLAINS. WILL HAVE TO MONITOR VISIBILITIES OVER THE NEXT FEW HOURS WITH LOW TEMPERATURE / DEWPOINT SPREADS...OTHERWISE SKIES WILL BE MOSTLY SUNNY EARLY THIS MORNING. A POTENTIAL CONCERN FOR TODAY IS THE CHANCE FOR AN ISOLATED SHOWER OR THUNDERSTORM THIS AFTERNOON. SOME OF THE HI-RES MODEL SOLUTIONS HAVE HINTED AT THE POSSIBILITY OF AN ISOLATED SHOWER AS LOW LEVEL LAPSE RATES STEEPEN THIS AFTERNOON. FORECAST SOUNDINGS SHOW ONLY A SMALL AREA OF INCREASED MOISTURE (RELATIVE HUMIDITY) THIS AFTERNOON AROUND H85...WITH VERY DRY AIR IN PLACE IN THE LOW LEVELS. FOR NOW...WILL STAY WITH THE DRY FORECAST AND ONLY SHOW SOME INCREASE IN CLOUDS AS CUMULUS DEVELOPS THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL BE IN THE 80S. TONIGHT WILL SEE CLEARING SKIES AS THE CUMULUS DISSIPATES DURING THE EVENING. LOWS SHOULD GENERALLY BE IN THE MID 50S TO NEAR 60. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 314 AM CDT MON AUG 10 2015 DETERMINISTIC MODELS AND ENSEMBLE OUTPUT CONTINUE TO INDICATE STRONG UPPER LEVEL RIDGE BUILDING ACROSS WESTERN NORTH AMERICA AND SLOWLY MOVING ACROSS THE NORTHERN PLAINS BY LATE WEEK AS DEEP UPPER LOW MOVES INTO THE PAC NW BY THU/FRI. HIGH TEMPS ACROSS WESTERN AND CENTRAL ND WILL REACH MID/UPPER 90S BY WEDNESDAY AND THURSDAY WITH THE HIGHEST TEMPS ACROSS THE WEST. TEMPS WILL REMAIN ABOVE NORMAL...BUT SLIGHTLY LOWER BY FRI AND SAT AS UPPER LEVEL RIDGE AXIS SLOWLY PUSHES EAST OF US. MODELS GENERATE SOME CONVECTIVE PRECIP TUE NIGHT AND WED WITH GFS INDICATING SOME ELEVATED INSTABILITY AND A LOW LEVEL JET STRENGTHENING TUE NIGHT AND UP TO 2000 J/KG OF SURFACE BASED CAPE ON WEDNESDAY. PROXIMITY OF UPPER LEVEL RIDGE AND GENERAL ANTICYCLONIC FLOW WILL LIMIT CONVECTIVE POTENTIAL...BUT AN ISOLATED SHOWER OR THUNDERSTORM IS NOT OUT OF THE QUESTION WITH MODELS SHOWING A FEW WEAK SHORTWAVE TROUGHS RIDING OVER THE RIDGE. BETTER CHANCE FOR PRECIP WILL BEGIN FRIDAY EVENING AS COLD FRONT MOVES THROUGH THE REGION ON SATURDAY PER GFS/ECMWF. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 542 AM CDT MON AUG 10 2015 EXPECT VFR CONDITIONS TO DOMINATE FOR THE 12Z TAF PERIOD. VERY PATCHY FOG HAS DEVELOPED ACROSS PARTS OF CENTRAL INTO NORTHEAST NORTH DAKOTA...BUT DO NOT EXPECT IT TO PERSIST. WILL MONITOR THE LATEST OBSERVATIONS AND TRY TO KEEP ANY FOG MENTION TO A MINIMUM. WINDS SHOULD STAY LESS THAN 10KTS THROUGH THE PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...CK LONG TERM...JNS AVIATION...CK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
542 AM CDT MON AUG 10 2015 .UPDATE... ISSUED AT 542 AM CDT MON AUG 10 2015 MADE A QUICK UPDATE TO ADD PATCHY FOG FROM HETTINGER...THOUGH WASHBURN...TO RUGBY AND ROLETTE. OBSERVATIONS THIS MORNING HAVE FAVORED THAT REGION FOR FOG...AND THIS ALSO LINES UP WITH THE LATEST ITERATIONS OF THE HRRR AND RAP13. A COUPLE ROGUE SHOWERS DEVELOPED OVERNIGHT IN PARTS OF LOGAN AND MCINTOSH COUNTIES...BUT THOSE HAVE DISSIPATED. THE REMAINDER OF THE FORECAST IS ON TRACK AND ONLY ADJUSTED TO CAPTURE THE LATEST OBSERVATIONS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 314 AM CDT MON AUG 10 2015 A QUIET START TO THE DAY IS EXPECTED WITH HIGH PRESSURE IN PLACE AT THE SURFACE ACROSS THE NORTHERN PLAINS. WILL HAVE TO MONITOR VISIBILITIES OVER THE NEXT FEW HOURS WITH LOW TEMPERATURE / DEWPOINT SPREADS...OTHERWISE SKIES WILL BE MOSTLY SUNNY EARLY THIS MORNING. A POTENTIAL CONCERN FOR TODAY IS THE CHANCE FOR AN ISOLATED SHOWER OR THUNDERSTORM THIS AFTERNOON. SOME OF THE HI-RES MODEL SOLUTIONS HAVE HINTED AT THE POSSIBILITY OF AN ISOLATED SHOWER AS LOW LEVEL LAPSE RATES STEEPEN THIS AFTERNOON. FORECAST SOUNDINGS SHOW ONLY A SMALL AREA OF INCREASED MOISTURE (RELATIVE HUMIDITY) THIS AFTERNOON AROUND H85...WITH VERY DRY AIR IN PLACE IN THE LOW LEVELS. FOR NOW...WILL STAY WITH THE DRY FORECAST AND ONLY SHOW SOME INCREASE IN CLOUDS AS CUMULUS DEVELOPS THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL BE IN THE 80S. TONIGHT WILL SEE CLEARING SKIES AS THE CUMULUS DISSIPATES DURING THE EVENING. LOWS SHOULD GENERALLY BE IN THE MID 50S TO NEAR 60. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 314 AM CDT MON AUG 10 2015 DETERMINISTIC MODELS AND ENSEMBLE OUTPUT CONTINUE TO INDICATE STRONG UPPER LEVEL RIDGE BUILDING ACROSS WESTERN NORTH AMERICA AND SLOWLY MOVING ACROSS THE NORTHERN PLAINS BY LATE WEEK AS DEEP UPPER LOW MOVES INTO THE PAC NW BY THU/FRI. HIGH TEMPS ACROSS WESTERN AND CENTRAL ND WILL REACH MID/UPPER 90S BY WEDNESDAY AND THURSDAY WITH THE HIGHEST TEMPS ACROSS THE WEST. TEMPS WILL REMAIN ABOVE NORMAL...BUT SLIGHTLY LOWER BY FRI AND SAT AS UPPER LEVEL RIDGE AXIS SLOWLY PUSHES EAST OF US. MODELS GENERATE SOME CONVECTIVE PRECIP TUE NIGHT AND WED WITH GFS INDICATING SOME ELEVATED INSTABILITY AND A LOW LEVEL JET STRENGTHENING TUE NIGHT AND UP TO 2000 J/KG OF SURFACE BASED CAPE ON WEDNESDAY. PROXIMITY OF UPPER LEVEL RIDGE AND GENERAL ANTICYCLONIC FLOW WILL LIMIT CONVECTIVE POTENTIAL...BUT AN ISOLATED SHOWER OR THUNDERSTORM IS NOT OUT OF THE QUESTION WITH MODELS SHOWING A FEW WEAK SHORTWAVE TROUGHS RIDING OVER THE RIDGE. BETTER CHANCE FOR PRECIP WILL BEGIN FRIDAY EVENING AS COLD FRONT MOVES THROUGH THE REGION ON SATURDAY PER GFS/ECMWF. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 542 AM CDT MON AUG 10 2015 EXPECT VFR CONDITIONS TO DOMINATE FOR THE 12Z TAF PERIOD. VERY PATCHY FOG HAS DEVELOPED ACROSS PARTS OF CENTRAL INTO NORTHEAST NORTH DAKOTA...BUT DO NOT EXPECT IT TO PERSIST. WILL MONITOR THE LATEST OBSERVATIONS AND TRY TO KEEP ANY FOG MENTION TO A MINIMUM. WINDS SHOULD STAY LESS THAN 10KTS THROUGH THE PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CK SHORT TERM...CK LONG TERM...JNS AVIATION...CK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1108 AM EDT MON AUG 10 2015 .SYNOPSIS... MUGGY TODAY. WEAK LOW PRESSURE DEVELOPS IN UPPER OHIO VALLEY MOVES NORTHEAST TONIGHT...DRAGGING A COLD FRONT THRU LATE TONIGHT AND TUESDAY MORNING. DRIER WITH COOLER NIGHTS WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... NO REAL CHANGES TO THE FORECAST. TWEEKED POPS A TAD TO ACCOUNT FOR DEVELOPING CONVECTION. OTHERWISE, NO OTHER CHANGES ARE EXPECTED. PREVIOUS DISCUSSION... ONE OF THOSE MUGGY AUGUST DAYS...PROBABLY WISE/BEST...NOT TO RUN WITH ANY ONE MODEL SOLUTION. WITH ADJUSTMENTS BEING MADE DURING THE COURSE OF THE DAY AND EVENING BASED ON THE MOST RECENT CONVECTIVE TRENDS. AT 07Z...ONE MID LEVEL VORT MAX STRETCHED OUT FROM SRN WV NNW TOWARD ZZV. IT SHOULD EXIT TO OUR EAST 12Z TO 14Z. NOT MUCH VIRGA IN THIS AIRMASS...SO IT WAS CAUSING SOME DISORGANIZED AREAS OF RW- OR SPRINKLES THIS PREDAWN. ANOTHER DISTURBANCE DROPPING SE FROM WRN KY TOWARD MIDDLE TENNESSEE. EVEN THOUGH MAIN CONVECTIVE CLUSTERS WILL DROP INTO TN...FEEL SOME OF ITS AFFECTS... IN THIS MUGGY AIR...COULD RIPPLE EAST AND CAUSE SHOWERS TO FORM INTO OUR TRI STATE AND SW VA THIS MORNING. MATTER OF FACT...THE 00Z NAM HAD THE EQUILIBRIUM LEVEL QUICKLY REACHING TOWARD 35 THSD BY 15Z AT HTS. YET...IT DOES NOT GET ANY HIGHER...THIS AFTERNOON OR EVENING. WEAK SURFACE LOW EXPECTED TO FORM IN THE UPPER OHIO VALLEY...SAY OVER OHIO...THIS AFTERNOON. THE WEAK WIND FLOW DOES INCREASE...MAYBE SOME 15 KNOTS AT 925 MBS BY 21Z ON THE RAP IN THE OHIO VALLEY COUNTIES. THE 06Z NAM DEEPENS THIS CIRCULATION EVEN MORE WITH SOME 25 KNOTS BY 00Z TUESDAY. 700 MB FLOW ONLY INCREASES TO ABOUT 20 TO 25 KNOTS. EXPECT CELL MOVEMENT THIS AFTERNOON AND EVENING TO BE ABOUT 25 KNOTS...WHICH IS NOT TOO FAST...AND NOT TOO SLOW. WILL BASE FORECAST ON ASSOCIATED TROF/FRONT FORM THE EXITING WEAK LOW PRESSURE...TO REACH INTO OUR SE OHIO AROUND 06Z TUESDAY...THEN REACHING BETWEEN CKB AND EKN TO NEAR HTS BY 12Z TUESDAY. TRYING TO TIME THE PREFRONTAL CONVECTION THAT FORMS IN OHIO THIS AFTERNOON...AND HOW FAST TO PUSH THE HIGHER POPS EAST... THROUGH WEST VIRGINIA...IS ONE HEADACHE. TRIED TO HAVE LIKELY POPS LATE THIS AFTERNOON IN SE OHIO...REACHING OHIO RIVER AT 00Z TUESDAY...THEN TOWARD EKN TO CRW 03Z TO 06Z TUESDAY. COULD SEE SOME SEVERE STORM DEVELOPMENT IN THIS HUMID ENVIRONMENT NEAR OUR SE OHIO COUNTIES IN THE OHIO VALLEY LATE THIS AFTERNOON...THEN MOVE EAST DURING THE EVENING INTO WV AND NRN KY . UPDATED THE HWO AT 630 AM...WILL HIGHLIGHT SOUTHEAST OHIO INTO WRN WV AND NE KENTUCKY FOR POSSIBLE STRONG TO SEVERE CONVECTION LATE THIS AFTERNOON OR THIS EVENING. WOULD NOT BE SURPRISED IF SPC UPDATES ON DAY 1...INCLUDED SOME SLIGHT RISK AREAS...AS THIS WHOLE SYSTEM EVOLVES/DEVELOPS. OVERALL THOUGH...THE FLOW NOT STRONG AND EL PEAKS ABOUT 35 THSD FT. ACTUALLY MOST COUNTIES...ESPECIALLY ALONG THE ROUTE 50 CORRIDOR COULD ACTUALLY USE SOME RAIN. MAXIMUM TEMPERATURE FORECAST TODAY DEPENDENT ON AFTERNOON COVERAGE OF CONVECTION... BUT TRIED TO STAY SLIGHTLY UNDER MOST 00Z MOS GUIDANCE...AND LOWER THAN THE OBSERVED ON SUNDAY. THE LOWEST CEILINGS SHOULD BE ASSOCIATED WITH THE FRONT...SO LEAVING LINGERING SHOWERS IN THE WAKE OF THE FRONT THRU 12Z TUESDAY NEAR THE OHIO RIVER...WITH SOME LIKELY POPS AT 12Z TUESDAY STILL OVER THE CENTRAL WV MOUNTAINS WITH THE FRONT. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... COLD FRONT WILL BE PUSHING EAST OF THE CWA BY MIDDAY TUESDAY. SEVERAL UPPER LEVEL SHORTWAVE TROUGHS WILL ROTATE AROUND A 500MB LOW OVER QUEBEC...SO LINGER POPS THROUGH MUCH OF THE DAY. OVERALL TROUGH AXIS PASSES LATE TUESDAY...HOWEVER NAM AND GFS SHOW ANOTHER RATHER POTENT SHORTWAVE TROUGH/VORT MAX DIGS IN ON WEDNESDAY. THE ECMWF KEEPS THINGS FARTHER NORTH. THIS FEATURE SHOULD BE FIGHTING INCREASINGLY DRIER AIR IN THE LOW LEVELS...BUT DID INCLUDE ISOLATED TO SCATTERED SHOWERS ACROSS NORTHERN AND EASTERN CWA. HIGH TEMPS WILL GENERALLY BE BELOW NORMAL THROUGH THE SHORT TERM. LOWS SHOULD BE JUST A TOUCH BELOW NORMAL TUESDAY NIGHT AS COLD AIR FILTERS IN...AND THEN A MILD 5-10 DEGREES BELOW NORMAL WEDNESDAY NIGHT. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE WEEKEND. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS WILL PREVAIL OUTSIDE OF BRIEF MVFR CONDITIONS IN CONVECTION THIS AFTERNOON. INCREASED THUNDERSTORM COVERAGE IN SE OHIO AFTER 20Z...THEN MOVE INTO WV FOR 00Z TO 06Z. COULD NOT RULE OUT A FEW STRONG TO SEVERE CELLS. CEILINGS LOWER NEAR FRONT TO 2 TO 3 THSD FT BKN TO OVC AND VSBY NEAR 3 MILES IN ANY SHOWER/STORM. LINGERING SHOWERS 06Z TO 12Z TUESDAY...CEILINGS COULD LOWER TO NEAR 1 THSD FT NEAR FRONT AND VSBY 3 TO 5 MILES...AND LINGER PAST 12Z TUESDAY IN THE WV MOUNTAINS. HAVE ASSOCIATED FRONT/WIND SHIFT REACHING INTO OUR SE OHIO BY 06Z TUESDAY...THEN NEAR A EKN TO HTS LINE BY 12Z TUESDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: SPECIFIC TIMING AND DURATION OF ROUNDS OF CONVECTION THIS AFTERNOON AND OVERNIGHT TONIGHT WILL VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 EDT 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H M M M M M H M M M BKW CONSISTENCY H H H H M M M M M M H H EKN CONSISTENCY H H H H M M M M M M M H PKB CONSISTENCY H H H H H M M M M M M M CKB CONSISTENCY H H H H H H H H H H M M AFTER 12Z TUESDAY... NEAR AND IN WAKE OF FRONT...LINGERING IFR CEILINGS IN LIGHTER SHOWERS THROUGH TUESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...JS/KTB SHORT TERM...MZ LONG TERM...30 AVIATION...JS/KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
645 AM EDT MON AUG 10 2015 .SYNOPSIS... MUGGY TODAY. WEAK LOW PRESSURE DEVELOPS IN UPPER OHIO VALLEY MOVES NORTHEAST TONIGHT...DRAGGING A COLD FRONT THRU LATE TONIGHT AND TUESDAY MORNING. DRIER WITH COOLER NIGHTS WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... ONE OF THOSE MUGGY AUGUST DAYS...PROBABLY WISE/BEST...NOT TO RUN WITH ANY ONE MODEL SOLUTION. WITH ADJUSTMENTS BEING MADE DURING THE COURSE OF THE DAY AND EVENING BASED ON THE MOST RECENT CONVECTIVE TRENDS. AT 07Z...ONE MID LEVEL VORT MAX STRETCHED OUT FROM SRN WV NNW TOWARD ZZV. IT SHOULD EXIT TO OUR EAST 12Z TO 14Z. NOT MUCH VIRGA IN THIS AIRMASS...SO IT WAS CAUSING SOME DISORGANIZED AREAS OF RW- OR SPRINKLES THIS PREDAWN. ANOTHER DISTURBANCE DROPPING SE FROM WRN KY TOWARD MIDDLE TENNESSEE. EVEN THOUGH MAIN CONVECTIVE CLUSTERS WILL DROP INTO TN...FEEL SOME OF ITS AFFECTS... IN THIS MUGGY AIR...COULD RIPPLE EAST AND CAUSE SHOWERS TO FORM INTO OUR TRI STATE AND SW VA THIS MORNING. MATTER OF FACT...THE 00Z NAM HAD THE EQUILIBRIUM LEVEL QUICKLY REACHING TOWARD 35 THSD BY 15Z AT HTS. YET...IT DOES NOT GET ANY HIGHER...THIS AFTERNOON OR EVENING. WEAK SURFACE LOW EXPECTED TO FORM IN THE UPPER OHIO VALLEY...SAY OVER OHIO...THIS AFTERNOON. THE WEAK WIND FLOW DOES INCREASE...MAYBE SOME 15 KNOTS AT 925 MBS BY 21Z ON THE RAP IN THE OHIO VALLEY COUNTIES. THE 06Z NAM DEEPENS THIS CIRCULATION EVEN MORE WITH SOME 25 KNOTS BY 00Z TUESDAY. 700 MB FLOW ONLY INCREASES TO ABOUT 20 TO 25 KNOTS. EXPECT CELL MOVEMENT THIS AFTERNOON AND EVENING TO BE ABOUT 25 KNOTS...WHICH IS NOT TOO FAST...AND NOT TOO SLOW. WILL BASE FORECAST ON ASSOCIATED TROF/FRONT FORM THE EXITING WEAK LOW PRESSURE...TO REACH INTO OUR SE OHIO AROUND 06Z TUESDAY...THEN REACHING BETWEEN CKB AND EKN TO NEAR HTS BY 12Z TUESDAY. TRYING TO TIME THE PREFRONTAL CONVECTION THAT FORMS IN OHIO THIS AFTERNOON...AND HOW FAST TO PUSH THE HIGHER POPS EAST... THROUGH WEST VIRGINIA...IS ONE HEADACHE. TRIED TO HAVE LIKELY POPS LATE THIS AFTERNOON IN SE OHIO...REACHING OHIO RIVER AT 00Z TUESDAY...THEN TOWARD EKN TO CRW 03Z TO 06Z TUESDAY. COULD SEE SOME SEVERE STORM DEVELOPMENT IN THIS HUMID ENVIRONMENT NEAR OUR SE OHIO COUNTIES IN THE OHIO VALLEY LATE THIS AFTERNOON...THEN MOVE EAST DURING THE EVENING INTO WV AND NRN KY . UPDATED THE HWO AT 630 AM...WILL HIGHLIGHT SOUTHEAST OHIO INTO WRN WV AND NE KENTUCKY FOR POSSIBLE STRONG TO SEVERE CONVECTION LATE THIS AFTERNOON OR THIS EVENING. WOULD NOT BE SURPRISED IF SPC UPDATES ON DAY 1...INCLUDED SOME SLIGHT RISK AREAS...AS THIS WHOLE SYSTEM EVOLVES/DEVELOPS. OVERALL THOUGH...THE FLOW NOT STRONG AND EL PEAKS ABOUT 35 THSD FT. ACTUALLY MOST COUNTIES...ESPECIALLY ALONG THE ROUTE 50 CORRIDOR COULD ACTUALLY USE SOME RAIN. MAXIMUM TEMPERATURE FORECAST TODAY DEPENDENT ON AFTERNOON COVERAGE OF CONVECTION... BUT TRIED TO STAY SLIGHTLY UNDER MOST 00Z MOS GUIDANCE...AND LOWER THAN THE OBSERVED ON SUNDAY. THE LOWEST CEILINGS SHOULD BE ASSOCIATED WITH THE FRONT...SO LEAVING LINGERING SHOWERS IN THE WAKE OF THE FRONT THRU 12Z TUESDAY NEAR THE OHIO RIVER...WITH SOME LIKELY POPS AT 12Z TUESDAY STILL OVER THE CENTRAL WV MOUNTAINS WITH THE FRONT. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... COLD FRONT WILL BE PUSHING EAST OF THE CWA BY MIDDAY TUESDAY. SEVERAL UPPER LEVEL SHORTWAVE TROUGHS WILL ROTATE AROUND A 500MB LOW OVER QUEBEC...SO LINGER POPS THROUGH MUCH OF THE DAY. OVERALL TROUGH AXIS PASSES LATE TUESDAY...HOWEVER NAM AND GFS SHOW ANOTHER RATHER POTENT SHORTWAVE TROUGH/VORT MAX DIGS IN ON WEDNESDAY. THE ECMWF KEEPS THINGS FARTHER NORTH. THIS FEATURE SHOULD BE FIGHTING INCREASINGLY DRIER AIR IN THE LOW LEVELS...BUT DID INCLUDE ISOLATED TO SCATTERED SHOWERS ACROSS NORTHERN AND EASTERN CWA. HIGH TEMPS WILL GENERALLY BE BELOW NORMAL THROUGH THE SHORT TERM. LOWS SHOULD BE JUST A TOUCH BELOW NORMAL TUESDAY NIGHT AS COLD AIR FILTERS IN...AND THEN A MILD 5-10 DEGREES BELOW NORMAL WEDNESDAY NIGHT. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE WEEKEND. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... IN THE WAKE OF THE OVERNIGHT MID LEVEL DISTURBANCE AND A FEW LIGHT SHOWERS OR SPRINKLES...THE MID DECK WAS THINNING AT 10Z...ALLOWING SOME DENSER VALLEY FOG IN THE WV MOUNTAIN VALLEYS. THE FOG SHOULD DISSIPATE BY 13Z. AT 10Z...MAIN CONVECTION COMPLEXES DROPPING SE THROUGH WRN KY AND TN...BUT A FEW SHOWERS MAY FORM FURTHER E AND AFFECT HTS TRI STATE AND SW VA THIS MORNING. WILL HAVE MOSTLY 3 TO 5 THSD FT SCT TO BKN AGL CU FORMING TODAY WITH LAYERS ABOVE. COULD NOT TIME ANY DEFINITE ROUNDS OF CONVECTION THIS AFTERNOON SO HAVE VCNTY THUNDERSTORM IN MOST TAF SITES. HOWEVER...LATER IN THE DAY...TRIED TO INCREASE THUNDERSTORM COVERAGE IN SE OHIO AFTER 20Z...THEN MOVE INTO WV FOR 00Z TO 06Z. COULD NOT RULE OUT A FEW STRONG TO SEVERE CELLS. CEILINGS LOWER NEAR FRONT TO 2 TO 3 THSD FT BKN TO OVC AND VSBY NEAR 3 MILES IN ANY SHOWER/STORM. LINGERING SHOWERS 06Z TO 12Z TUESDAY...CEILINGS COULD LOWER TO NEAR 1 THSD FT NEAR FRONT AND VSBY 3 TO 5 MILES...AND LINGER PAST 12Z TUESDAY IN THE WV MOUNTAINS. HAVE ASSOCIATED FRONT/WIND SHIFT REACHING INTO OUR SE OHIO BY 06Z TUESDAY...THEN NEAR A EKN TO HTS LINE BY 12Z TUESDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: SPECIFIC TIMING AND DURATION OF ROUNDS OF CONVECTION THIS AFTERNOON AND OVERNIGHT TONIGHT WILL VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE MON 08/10/15 UTC 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 EDT 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16 CRW CONSISTENCY M H H H H H H H H H H H HTS CONSISTENCY M H H H H H H H H M M M BKW CONSISTENCY H H H H H H H H H H M M EKN CONSISTENCY L L M M H H H H H H M M PKB CONSISTENCY M H H H H H H H H H H M CKB CONSISTENCY M M H H H H H H H H H H AFTER 12Z TUESDAY... NEAR AND IN WAKE OF FRONT...LINGERING IFR CEILINGS IN LIGHTER SHOWERS THROUGH TUESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...30 AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
604 AM EDT MON AUG 10 2015 .SYNOPSIS... MUGGY TODAY. WEAK LOW PRESSURE DEVELOPS IN UPPER OHIO VALLEY MOVES NORTHEAST TONIGHT...DRAGGING A COLD FRONT THRU LATE TONIGHT AND TUESDAY MORNING. DRIER WITH COOLER NIGHTS WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... ONE OF THOSE MUGGY AUGUST DAYS...PROBABLY WISE/BEST...NOT TO RUN WITH ANY ONE MODEL SOLUTION. WITH ADJUSTMENTS BEING MADE DURING THE COURSE OF THE DAY AND EVENING BASED ON THE MOST RECENT CONVECTIVE TRENDS. AT 07Z...ONE MID LEVEL VORT MAX STRETCHED OUT FROM SRN WV NNW TOWARD ZZV. IT SHOULD EXIT TO OUR EAST 12Z TO 14Z. NOT MUCH VIRGA IN THIS AIRMASS...SO IT WAS CAUSING SOME DISORGANIZED AREAS OF RW- OR SPRINKLES THIS PREDAWN. ANOTHER DISTURBANCE DROPPING SE FROM WRN KY TOWARD MIDDLE TENNESSEE. EVEN THOUGH MAIN CONVECTIVE CLUSTERS WILL DROP INTO TN...FEEL SOME OF ITS AFFECTS... IN THIS MUGGY AIR...COULD RIPPLE EAST AND CAUSE SHOWERS TO FORM INTO OUR TRI STATE AND SW VA THIS MORNING. MATTER OF FACT...THE 00Z NAM HAD THE EQUILIBRIUM LEVEL QUICKLY REACHING TOWARD 35 THSD BY 15Z AT HTS. YET...IT DOES NOT GET ANY HIGHER...THIS AFTERNOON OR EVENING. WEAK SURFACE LOW EXPECTED TO FORM IN THE UPPER OHIO VALLEY...SAY OVER OHIO...THIS AFTERNOON. THE WEAK WIND FLOW DOES INCREASE...MAYBE SOME 15 KNOTS AT 925 MBS BY 21Z ON THE RAP IN THE OHIO VALLEY COUNTIES. THE 06Z NAM DEEPENS THIS CIRCULATION EVEN MORE WITH SOME 25 KNOTS BY 00Z TUESDAY. 700 MB FLOW ONLY INCREASES TO ABOUT 20 TO 25 KNOTS. EXPECT CELL MOVEMENT THIS AFTERNOON AND EVENING TO BE ABOUT 25 KNOTS...WHICH IS NOT TOO FAST...AND NOT TOO SLOW. WILL BASE FORECAST ON ASSOCIATED TROF/FRONT FORM THE EXITING WEAK LOW PRESSURE...TO REACH INTO OUR SE OHIO AROUND 06Z TUESDAY...THEN REACHING BETWEEN CKB AND EKN TO NEAR HTS BY 12Z TUESDAY. TRYING TO TIME THE PREFRONTAL CONVECTION THAT FORMS IN OHIO THIS AFTERNOON...AND HOW FAST TO PUSH THE HIGHER POPS EAST... THROUGH WEST VIRGINIA...IS ONE HEADACHE. TRIED TO HAVE LIKELY POPS LATE THIS AFTERNOON IN SE OHIO...REACHING OHIO RIVER AT 00Z TUESDAY...THEN TOWARD EKN TO CRW 03Z TO 06Z TUESDAY. COULD SEE SOME SEVERE STORM DEVELOPMENT IN THIS HUMID ENVIRONMENT NEAR OUR SE OHIO COUNTIES IN THE OHIO VALLEY LATE THIS AFTERNOON...THEN MOVE EAST THIS EVENING INTO WV. HOWEVER...AS OF THIS EARLY HOUR...COULD NOT HIGHLIGHT A SPECIFIC THREAT AREA. WOULD NOT BE SURPRISED IF SPC UPDATES ON DAY 1...INCLUDED SOME SLIGHT RISK AREAS...AS THIS WHOLE SYSTEM EVOLVES/DEVELOPS. OVERALL NOT TOO EXCITED WITH THE THIN CAPE AND RELATIVELY WEAK FLOW AS DISCUSSED. MOST COUNTIES...ESPECIALLY ALONG THE ROUTE 50 CORRIDOR COULD ACTUALLY USE SOME RAIN. MAXIMUM TEMPERATURE FORECAST TODAY DEPENDENT ON AFTERNOON COVERAGE OF CONVECTION... BUT TRIED TO STAY SLIGHTLY UNDER MOST 00Z MOS GUIDANCE...AND LOWER THAN THE OBSERVED ON SUNDAY. THE LOWEST CEILINGS SHOULD BE ASSOCIATED WITH THE FRONT...SO LEAVING LINGERING SHOWERS IN THE WAKE OF THE FRONT THRU 12Z TUESDAY NEAR THE OHIO RIVER...WITH SOME LIKELY POPS AT 12Z TUESDAY STILL OVER THE CENTRAL WV MOUNTAINS WITH THE FRONT. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... COLD FRONT WILL BE PUSHING EAST OF THE CWA BY MIDDAY TUESDAY. SEVERAL UPPER LEVEL SHORTWAVE TROUGHS WILL ROTATE AROUND A 500MB LOW OVER QUEBEC...SO LINGER POPS THROUGH MUCH OF THE DAY. OVERALL TROUGH AXIS PASSES LATE TUESDAY...HOWEVER NAM AND GFS SHOW ANOTHER RATHER POTENT SHORTWAVE TROUGH/VORT MAX DIGS IN ON WEDNESDAY. THE ECMWF KEEPS THINGS FARTHER NORTH. THIS FEATURE SHOULD BE FIGHTING INCREASINGLY DRIER AIR IN THE LOW LEVELS...BUT DID INCLUDE ISOLATED TO SCATTERED SHOWERS ACROSS NORTHERN AND EASTERN CWA. HIGH TEMPS WILL GENERALLY BE BELOW NORMAL THROUGH THE SHORT TERM. LOWS SHOULD BE JUST A TOUCH BELOW NORMAL TUESDAY NIGHT AS COLD AIR FILTERS IN...AND THEN A MILD 5-10 DEGREES BELOW NORMAL WEDNESDAY NIGHT. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE WEEKEND. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... IN THE WAKE OF THE OVERNIGHT MID LEVEL DISTURBANCE AND A FEW LIGHT SHOWERS OR SPRINKLES...THE MID DECK WAS THINNING AT 10Z...ALLOWING SOME DENSER VALLEY FOG IN THE WV MOUNTAIN VALLEYS. THE FOG SHOULD DISSIPATE BY 13Z. AT 10Z...MAIN CONVECTION COMPLEXES DROPPING SE THROUGH WRN KY AND TN...BUT A FEW SHOWERS MAY FORM FURTHER E AND AFFECT HTS TRI STATE AND SW VA THIS MORNING. WILL HAVE MOSTLY 3 TO 5 THSD FT SCT TO BKN AGL CU FORMING TODAY WITH LAYERS ABOVE. COULD NOT TIME ANY DEFINITE ROUNDS OF CONVECTION THIS AFTERNOON SO HAVE VCNTY THUNDERSTORM IN MOST TAF SITES. HOWEVER...LATER IN THE DAY...TRIED TO INCREASE THUNDERSTORM COVERAGE IN SE OHIO AFTER 20Z...THEN MOVE INTO WV FOR 00Z TO 06Z. COULD NOT RULE OUT A FEW STRONG TO SEVERE CELLS. CEILINGS LOWER NEAR FRONT TO 2 TO 3 THSD FT BKN TO OVC AND VSBY NEAR 3 MILES IN ANY SHOWER/STORM. LINGERING SHOWERS 06Z TO 12Z TUESDAY...CEILINGS COULD LOWER TO NEAR 1 THSD FT NEAR FRONT AND VSBY 3 TO 5 MILES...AND LINGER PAST 12Z TUESDAY IN THE WV MOUNTAINS. HAVE ASSOCIATED FRONT/WIND SHIFT REACHING INTO OUR SE OHIO BY 06Z TUESDAY...THEN NEAR A EKN TO HTS LINE BY 12Z TUESDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: SPECIFIC TIMING AND DURATION OF ROUNDS OF CONVECTION THIS AFTERNOON AND OVERNIGHT TONIGHT WILL VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE MON 08/10/15 UTC 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 EDT 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16 CRW CONSISTENCY M H H H H H H H H H H H HTS CONSISTENCY M H H H H H H H H M M M BKW CONSISTENCY H H H H H H H H H H M M EKN CONSISTENCY L L M M H H H H H H M M PKB CONSISTENCY M H H H H H H H H H H M CKB CONSISTENCY M M H H H H H H H H H H AFTER 12Z TUESDAY... NEAR AND IN WAKE OF FRONT...LINGERING IFR CEILINGS IN LIGHTER SHOWERS THROUGH TUESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...30 AVIATION...KTB
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1057 AM CDT MON AUG 10 2015 .UPDATE... LOWERED TEMPS A FEW DEGREES ACROSS THE NORTH AND ADJUSTED POPS SLIGHTLY. && .DISCUSSION... SCATTERED SHOWERS AND STORMS CONTINUE ALONG A WEAK MID LEVEL CONVERGENCE ZONE ACROSS NORTH CENTRAL OK. THIS ZONE WILL SLOWLY SHIFT SOUTHWARD DURING THE DAY BUT WITH LITTLE TO NO OTHER SUPPORT PRESENT (LLJ DISSIPATING) EXPECT COVERAGE WILL DIMINISH THROUGH THIS AFTERNOON. THE HRRR APPEARS TO HAVE A PRETTY GOOD HANDLE ON THE FORECAST SO WEIGHTED POPS HEAVILY TOWARDS IT. TEMPS WHERE ALSO LOWERED 2-4 DEGREES ACROSS NORTHERN OK...AND PORTIONS OF CENTRAL OK...WHERE CLOUD COVER WILL LIKELY LINGER THROUGH THE DAY. ALL UPDATED PRODUCTS HAVE BEEN SENT. && .PREV DISCUSSION... /ISSUED 338 AM CDT MON AUG 10 2015/ DISCUSSION... MAIN CONCERNS WILL BE PRECIP ACROSS THE NORTH AND HEAT FARTHER SOUTH TODAY AND THEN COOL-OFF AND PRECIP CHANCES THIS WEEK. CONT TO SEE SHOWERS AND THUNDERSTORMS DEVELOP ACROSS NORTHWEST INTO NORTHERN OKLAHOMA THIS MORNING NEAR A SLOW MOVING COLD FRONT. THIS FRONT IS A BIT SLOWER THAN MODELS HAVE BEEN SHOWING. THIS WILL ALLOW FOR TEMPS TO BE A BIT WARMER ACROSS PARTS OF THE AREA TODAY. BECAUSE OF THIS WE WILL END UP WITH SOME HIGHER HEAT INDICES AND WILL NECESSITATE THE NEED TO BRING THE HEAT ADVISORY FARTHER NORTH INTO CENTRAL OKLAHOMA. FRONT STILL EXPECTED TO PUSH SOUTH TOWARD THE RED RIVER BY TUESDAY MORNING. SLIGHTLY COOLER TEMPS EXPECTED BEHIND THE FRONT. AS THIS IS OCCURRING... UPPER RIDGE WILL BE BUILDING BACK NORTH ACROSS THE SOUTHERN/CENTRAL ROCKIES. MODELS CONT TO INDICATE AT LEAST A CHANCE FOR SOME ADDITIONAL PRECIP CHANCES INTO THE MIDDLE OF THE WEEK AS WE COME UNDER THE INFLUENCE OF WEAK NORTHWEST FLOW. HOWEVER TODAY`S MODEL RUNS HAVE SHIFTED THE MOISTURE PLUME FARTHER WEST AND KEEP MUCH IN THE WAY OF PRECIP CONFINED TO FAR WESTERN OKLAHOMA AND THE EASTERN TEXAS PANHANDLE AS WE GET INTO WED/THU TIMEFRAME. BEYOND THIS IT APPEARS THAT MOISTURE PLUME WILL DISSIPATE AND UPPER FLOW BECOMES MORE NORTHERLY AS UPPER RIDGE CONT BUILD NORTH AND NORTHEAST INTO THE CENTRAL AND NORTHERN PLAINS. ALTHOUGH DRY... THIS PATTERN SHOULD KEEP THE HOTTEST TEMPS TO OUR WEST AND NORTH BY LATE WEEK. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 96 74 90 70 / 30 20 10 10 HOBART OK 97 74 93 70 / 30 20 20 20 WICHITA FALLS TX 104 76 97 73 / 0 10 20 10 GAGE OK 91 70 87 68 / 50 30 30 20 PONCA CITY OK 92 73 89 68 / 60 10 0 10 DURANT OK 104 77 97 73 / 0 10 10 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR OKZ025>032-039>043- 045>048-050>052. TX...NONE. && $$ 03/14
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
601 AM CDT MON AUG 10 2015 .DISCUSSION... /ISSUED 439 AM CDT MON AUG 10 2015/ A COMPLEX WEATHER DAY ACROSS THE MIDSOUTH. THE UPPER LEVEL RIDGE THAT BROUGHT TRIPLE DIGIT HEAT CLOSE TO THE MIDSOUTH YESTERDAY HAD RETROGRADED OVER THE PAST 12 HOURS...RETURNING NORTHWEST FLOW ALOFT TO THE MIDSOUTH. SEVERAL THUNDERSTORM COMPLEXES HAD FORMED OVER SOUTHERN MO EARLY THIS MORNING...MOVING SOUTHEAST ALONG THE UPPER RIDGE PERIPHERY. ASSUMING THE COLD POOL CAN REMAIN ESTABLISHED THROUGH SUNRISE... 850-500MB THICKNESS FIELDS SUGGEST THESE STORMS WILL MOVE SOUTH/SOUTHEAST THROUGH NORTHEAST AR...WEST TN AND NORTHEAST MS. THE HRRR MODEL HAS BEEN CONSISTENT IN DEPICTING SUCH A SCENARIO. THE AIRMASS FEEDING THESE STORMS WAS RICH WITH MOISTURE...WITH PRECIPITABLE WATER VALUES AROUND 2.25 INCHES. THE LOW LEVEL JET HAS BEEN A RELATIVELY WEAK 20KTS...BUT ADEQUATE TO MAINTAIN STORMS EARLY THIS MORNING. THUNDERSTORM EVOLUTION THROUGH MIDDAY WILL HAVE SIGNIFICANT IMPACTS ON AFTERNOON HEAT INDICES. HAVE TRIMMED BACK HEAT HEADLINES TO REFLECT THE IMPACTS OF THUNDERSTORM OUTFLOW AND INITIAL CLOUD COVER. HEAT INDEX FORECAST CONFIDENCE IS MARGINAL... BUT PERHAPS BEST OVER THE MS RIVER DELTA...FROM CLARKSDALE TO CHARLESTON MS. THIS AREA WILL LEAST LIKELY BE IMPACTED BY THUNDERSTORM OUTFLOW AND CLOUD COVER...AND NEAREST TO THE AFTERNOON LOW LEVEL THERMAL RIDGE OVER SOUTHERN AR AND CENTRAL MS. A WEAK COLD FRONTAL PASSAGE APPEARS ON TRACK FOR LATE THIS EVENING AND EARLY OVERNIGHT. COOLER AND DRIER AIR WILL LAG 12 TO 18 HOURS BEHIND THE INITIAL WIND SHIFT...BUT LIKELY SUFFICIENT TO KEEP TUESDAY AFTERNOON HEAT INDICES BELOW ADVISORY CRITERIA. WEDNESDAY AND THURSDAY SHOULD SEE COOLER AND DRIER CONDITIONS...WITH NORTHERLY WINDS. DAYTIME TEMPS WILL GRADUALLY MODERATE TO NEAR NORMAL VALUES FROM FRIDAY THROUGH NEXT MONDAY...AS THE UPPER RIDGE BUILDS INTO THE MIDDLE MS RIVER VALLEY. RAIN CHANCES FROM MIDWEEK THROUGH EARLY NEXT WEEK APPEAR MINIMAL. PWB && .AVIATION... 12Z TAF SET LATEST HRRR SHOWS LINE OF CONVECTION THAT CURRENTLY STRETCHES FROM NEAR KMKL BACK TO THE NW ACROSS SW MO WILL CONTINUE TO PUSH SOUTHEAST THROUGH THE MIDSOUTH. CONVECTION SHOULD BE SOUTH OF KTUP BY 20Z. THEREAFTER...LOW CONFIDENCE ON TAFS IF ANY REDEVELOPMENT WILL OCCUR OR NOT. PUT IN VCTS WORDING AT KJBR AROUND 23Z FOR A COUPLE OF HOURS BUT HAVE MY DOUBTS IF ATMOSPHERE WILL RECOVER AS THICK CIRRUS DECK MAY BE OVER CWA FOR MOST OF DAY LIMITING DAYTIME HEATING. IF CLOUDS CLEAR OVERNIGHT COULD SEE SOME DENSE FOG AT SOME OF THE TAF SITES BUT FOR NOW HAVE LEFT MENTION OUT. WINDS WILL TURN AROUND TO THE N GUSTING TO 25-30 KTS INITIALLY BEHIND GUST FRONT MOVING SOUTHWARD. EXPECT WINDS SHOULD TURN BACK TO SSW BEFORE SWITCHING BACK TO THE NORTH. WIND DIRECTION AND SPEED WILL BE VARIABLE TODAY DUE TO THE CONVECTION. KRM && && .MEG WATCHES/WARNINGS/ADVISORIES... AR...EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR PHILLIPS. HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR CRITTENDEN-CROSS-LEE AR-POINSETT-ST. FRANCIS. MO...NONE. MS...EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR CALHOUN-COAHOMA-QUITMAN-TALLAHATCHIE-YALOBUSHA. HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR BENTON MS-CHICKASAW-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS- MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-TATE-TIPPAH-TUNICA- UNION. TN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR FAYETTE-SHELBY. && $$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
659 AM EDT MON AUG 10 2015 .SYNOPSIS... A WARM FRONT WILL LIFT SLOWLY NORTHEAST INTO THE REGION TODAY BEFORE SLIDING TO THE NORTH LATER TONIGHT. A STRONG COLD FRONT WILL PUSH EAST INTO THE MOUNTAINS BY EARLY TUESDAY AND ACROSS THE REMAINDER OF THE REGION BY TUESDAY EVENING. HIGH PRESSURE BUILDS INTO THE AREA BEHIND THE FRONT BY WEDNESDAY...BRINGING SOMEWHAT COOLER AND DRIER AIR FOR MIDWEEK INTO THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 220 AM EDT MONDAY... CLUSTERS OF VERY SLOW MOVING SHOWERS CONTINUE TO DEVELOP EARLY THIS MORNING ESPCLY OVER THE EAST IN ADVANCE OF A RATHER STRONG MID LEVEL WAVE DIPPING IN FROM THE NW JUST NORTH OF THE FRONT TO THE SW. THIS UNDERDONE BY MOST SHORT TERM MODELS INCLUDING THE HRRR SO BUMPING UP POPS TO AT LEAST CHANCE IN PARTS OF THE EAST AND SLIGHTS OVER THE WEST WHERE SHRA MORE SPOTTY NATURE CLOSER TO THE ACTUAL IMPULSE ALOFT. ONCE THIS FEATURE PASSES...LOTS OF UNCERTAINTY IN REGARDS TO THE CONVECTIVE ENVIRONMENT FROM LATE MORNING INTO THE AFTERNOON WITH A WARM FRONT HEADING INTO THE MOUNTAINS WHILE CLOUD COVER MAY STAY RATHER EXTENSIVE. GUIDANCE SOLUTIONS RANGE FROM THE BEST LIFT STAYING WEST OF THE MOUNTAINS UNTIL THIS EVENING SUPPORTING ONLY SCATTERED SHRA/TSRA BLUE RIDGE LATER...TO MORE OUTFLOW DRIVEN SUPPORT FROM THE MCS TO THE WEST WITH THIS RESIDUAL WAVE INTERACTING WITH AT LEAST SOME HEATING TO PRODUCE MORE MULTICELLULAR BANDS/CLUSTERS SIMILAR TO THE GFS/EC AND NCAR ENSEMBLE. THIS ALONG THE LINGERING HIGHER 85H THETA-E RIDGE WEST AND WHERE MODELS SUGGEST AT LEAST SOME DECENT CAPE MAY EXIST BUT LATER. THUS TRENDED MORE ALONG THOSE LINES AND BUMPED GOING POPS TO A PERIOD OF CATEGORICAL FAR WEST LATE AND LEFT LIKELYS IN ALL EXCEPT THE SE WHERE MAY BE LATE OR THIS EVENING BEFORE WHATS LEFT OF WESTERN COVERAGE MOVES EAST GIVEN WEAK STEERING. THIS COULD ALSO LEAD TO MORE OF A HEAVY RAINFALL THREAT VS SEVERE GIVEN RATHER MEAGER FLOW ALOFT AND LACK OF GOOD LAPSES UNLESS HEATING IS BETTER. NUDGED HIGHS DOWN A FEW DEGREES TO ACCOUNT FOR EARLY CLOUDS/SHRA AND POTENTIAL FOR QUICK DEVELOPMENT THIS AFTERNOON WITH ANY INSOLATION PER PWATS OF NEARLY 2 INCHES. GUIDANCE PUSHES A LOBE OF CONVECTION EAST/NE THIS EVENING AS THE WARM FRONT LIFTS NORTH AND THE COLD FRONT APPROACHES FROM THE WEST LATE. THINK BEST COVERAGE THROUGH MIDNIGHT OR SO WITH A RESIDUAL WAVE OVERHEAD BEFORE POSSIBLY SEEING A BREAK IN ALL EXCEPT THE NORTH LATE AS THE REGION SLIPS IN BETWEEN THE EXITING WARM FRONT AND UPSTREAM COLD FRONT. THE COLD FRONT MAY ALSO END UP BRINGING ANOTHER BAND OF SHRA INTO THE NW SLOPES TOWARD DAYBREAK...SO BLENDING POPS FROM LIKELYS MOST SPOTS TO INIT...TO MAINLY CHANCE IN ALL EXCEPT THE EAST/SE OVERNIGHT...AND OVER THE NW LATE. AGAIN MORE HEAVY RAIN POTENTIAL BUT EXPECT SHRA/TSRA TO MOVE A BIT MORE LATE AS WESTERLY FLOW DEEPENS SOME AHEAD OF THE COLD FRONT. STILL QUITE WARM/MUGGY WITH LOWS UPPER 60S/LOW 70S EXCEPT MID 60S VALLEYS AND IN SPOTS THAT RECEIVE HEAVIER RAINFALL. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM EDT MONDAY... MODELS HAVE OUR NEXT COLD FRONT MOVING ACROSS THE MOUNTAINS TUESDAY MORNING...STALLING NEAR THE BLUE RIDGE BY THE AFTERNOON. THE FRONT WILL EVENTUALLY CLEAR THE PIEDMONT TUESDAY EVENING...WAITING ON A SURFACE WAVE THAT WILL DEVELOP OVER THE CAROLINAS THEN MOVE OFF THE MID ATLANTIC COAST. WE CAN NOT RULE OUT SCATTERED SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS TUESDAY AFTERNOON...BUT THE MAJORITY OF THE STRONGER CONVECTION WILL BE ALONG AND EAST OF HWY 29. THE COVERAGE OF STRONG STORMS FOR THE FORECAST AREA WILL DEPEND ON THE LOCATION OF THE COLD FRONT AND THE TRACK OF THIS SURFACE WAVE. MOST MODELS ARE KEEPING THE STRONGER CONVECTION WITH THE SURFACE LOW OVER CENTRAL NORTH CAROLINA AND THE COASTAL PIEDMONT OF VIRGINIA. FOR NOW...WILL KEEP CHANCE POPS ACROSS THE FORECAST AREA. POPS WILL INCREASE IF THE FRONT REMAINS FARTHER TO THE WEST OR LOWER/DECREASING THROUGH THE AFTERNOON IF THE FRONT PUSHES EAST OF THE BLUE RIDGE. THE FRONT WILL BE ALONG THE CAROLINA COAST ON WEDNESDAY. THE DEW POINT FRONT WILL CROSS OVER THE REGION BY WEDNESDAY EVENING. WITH THE UPPER LEVEL TROUGH OVERHEAD AND LINGERING LOW LEVEL MOISTURE WEDNESDAY...A GOOD AMOUNT OF FAIR WEATHER CUMULUS CLOUDS WILL BE PRESENT...BUT NOT EXPECTING ANY TO PRODUCE MEASURE RAINFALL. TEMPERATURES ARE EXPECTED TO WARM TO NEAR NORMAL LEVELS TUESDAY. BEHIND THE FRONT...COOLER THAN NORMAL CONDITIONS ARE EXPECTED...70S WEST TO LOWER TO MID 80S EAST. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 200 PM SUNDAY... MODELS ARE ADVERTISING A RETREAT OF THE UPPER TROF OVER THE NORTHEAST THIS TIME FRAME. THE LARGE UPPER RIDGE OVER THE CENTRAL UNITED STATES SLIGHTLY RETROGRADES AND BUILDS NORTHEAST INTO THE OHIO VALLEY AS A LOW CUTS OFF SOMEWHERE AROUND THE NORTHERN GULF. AT THE SURFACE BY THURSDAY...HIGH PRESSURE WILL EXTEND FROM THE MID MISSISSIPPI VALLEY TO THE MID ATLANTIC REGION. THIS HIGH REMAINS OVER THE FORECAST AREA THROUGH FRIDAY. MODELS WERE BEGINNING TO SUGGEST A WEAK LOW OR SOME LEE TROUGHING MAY DEVELOP ON THE EASTERN SIDE OF THE APPALACHIANS ON SATURDAY. STILL NOT ENOUGH LIFT OR MOISTURE FOR ANY SUBSTANTIAL PROBABILITY OF PRECIPITATION. WILL BE STARTING THURSDAY MORNING WITH BELOW NORMAL MINIMUM TEMPERATURES THEN AIR MASS GRADUALLY MODERATES THROUGH SUNDAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 645 AM EDT MONDAY... CLUSTERS OF SHOWERS REMAIN PERSISTENT ESPCLY ACROSS THE EAST THIS MORNING WHERE ISOLATED COVERAGE CONTINUES TO AFFECT KLYH/KDAN. ALSO SEEING SPOTTY LIGHT SHOWERS OVER THE WEST SO WILL START OFF WITH AT LEAST A VCSH AT MOST LOCATIONS FROM THE BLUE RIDGE EAST EARLY ON. OTRW EXPECTING A MIX OF AC AND STRATO-CU CIGS THIS MORNING WITH MOST OF THE VFR VARIETY EXCEPT IN THE VICINITY OF EASTERN SHOWERS WHERE MVFR REMAINS POSSIBLE. ALSO SOME PATCHY FOG WILL MAKE FOR LOCALIZED MVFR/IFR THROUGH MID MORNING IN THE VALLEYS SUCH AS KLWB. ONCE THE CURRENT MID LEVEL WAVE PASSES...EXPECTING A LULL IN SHOWERS WITH SOME IMPROVEMENT IN CIGS BEFORE THE NEXT ROUND OF DEEPER MOISTURE ARRIVES THIS AFTERNOON. EXTENT OF MORE ORGANIZED CONVECTION REMAINS IN QUESTION THIS AFTERNOON WITH SOLUTIONS FOCUSING MAINLY OVER THE WEST FOR MORE WIDESPREAD COVERAGE. THIS SHOULD ALLOW ADDED SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP OVER THE WEST TOWARD EARLY AFTERNOON AND OUT EAST BY 20Z/4PM. THUS KEPT VCTS IN WITH MODERATE SHRA AT ALL SITES AFTER 18Z-20Z...WITH MVFR CIGS AT ALL EXCEPT VFR AT KDAN WHERE WILL HOLD OFF ON PRECIP. SHOWERS LIKELY TO LINGER OR REDEVELOP OVER THE WEST AFTER THE INITIAL CONVECTION SO LEAVING IN A MVFR MENTION INTO THE EVENING FOR ALL SITES EXCEPT OVER THE SOUTHEAST. SHOWERS AND ADDED TSRA COULD ALSO PERSIST OVER THE SOUTH AND WEST INTO LATER TONIGHT GIVEN OUTFLOW AND APPROACH OF THE COLD FRONT FROM THE WEST LATE. OTRW CUTTING BACK ON ADDED SHRA BY MIDNIGHT AT MOST LOCATIONS FOR NOW TO SEE HOW TRENDS UNFOLD WITH RUNS LATER TODAY. EXTENDED AVIATION DISCUSSION... TUESDAY...SHOWERS AND STORMS INCREASE AGAIN ACROSS THE REGION THANKS TO BOTH A FRONTAL BOUNDARY ENTERING THE REGION AND A SHORTWAVE TROUGH PROGRESSING EASTWARD THROUGH THE OHIO VALLEY. MAINLY VFR CONDITIONS ARE EXPECTED EXCEPT SUB-VFR CONDITIONS WHERE CONVECTION BECOMES MORE ORGANIZED. STRONGER STORMS WILL BE POSSIBLE LATER TUESDAY...MAINLY ALONG AND EAST OF THE KLYH-KDAN CORRIDOR. BY WEDNESDAY INTO FRIDAY...ANOTHER AREA OF HIGH PRESSURE BUILDS INTO THE REGION MAKING FOR OVERALL VFR CONDITIONS. PATCHY LATE NIGHT AND EARLY MORNING MOUNTAIN AND RIVER VALLEY FOG WILL AGAIN BE POSSIBLE...THOUGH AIRMASS WILL LIKELY BE DRIER. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS/JH NEAR TERM...JH SHORT TERM...RCS LONG TERM...AMS AVIATION...DS/JH/JM/WP Area Forecast Discussion National Weather Service Spokane WA 458 AM PDT MON AUG 10 2015 .SYNOPSIS... Hot weather will return for most of the work week with a continued chance of thunderstorms. Some storms may produce strong winds this afternoon and evening, mainly from the Northeast Blue Mountains and Camas Prairie areas and propagating as far north as the Northeast Mountains and Northern Panhandle. A few record high temperatures may be set Wednesday. A cold front thursday will bring another active thunderstorm threat along with cooler temperatures by next weekend. && .DISCUSSION... ...STRONG WINDS POSSIBLE WITH THUNDERSTORMS TODAY... Today and Tonight: There are a couple of vorticity maximums to watch out for today. Both are swinging around the base of a deep upper level low pressure system off of the coast of WA. The first, and more likely to have the bigger impact, is a shortwave disturbance currently pushing into northern California early this morning. This disturbance is progged to quickly push northeast and begin to push up into the region between noon and 200 PM PDT. Before we do see the effects of this disturbance, we will see some lingering light shower activity mainly across the northern half of the forecast area through this morning. Satellite imagery indicates a lot of clearing occurring behind these showers. This will set up a situation where there should be plenty of sunshine for the atmosphere to destabilize by the afternoon before the disturbance over California makes it this far north. Moisture will increase across the region with dew points expected to remain right around 50 degrees. This will set up the ingredients for a decent amount of surface based CAPE to work with. Models are generally showing somewhere in the neighborhood of 500-1500 J/KG of surface based CAPE across the eastern half of the forecast area; this generally includes areas east of a line extending from Ritzville to Republic. Thunderstorms are expected to initiate over northeast OR and in the southern Panhandle in the early afternoon and the push northward into southeastern WA and into the central Panhandle through the afternoon hours. Main threats with the thunderstorms will be for strong outflow winds. The WRF-NMM, WRF-ARW and HRRR models all show a signal of a gust front emanating northward from the convection. These models have also been consistent with this idea over the past few runs. I increase winds across the Palouse, into the basin, the Spokane- Coeur d`Alene corridor and into the northern mtns and ID Panhandle. These winds may also result in blowing dust with reduced visibility possible across portions of I-90 and highway 2. Forecast confidence in the strong outflow winds and blowing dust is only moderate and there is some bust potential as all the ingredients need to come together. With that said, there is enough evidence that concerns are increasing. Thunderstorms are also expected to include frequent cloud to ground lightning strikes. There will be some rain with the heavier thunderstorm cores, but, away from these course, there will also be a lot of evaporation that takes place. This should result in a higher potential for new fire starts from lightning strikes. The Fire Weather Watch will remain as is for now and will be reassessed later in the morning. A second disturbance will push up more across central OR in the wake of the first. This piece of energy will spark off more thunderstorms that will push northward through the late afternoon hours. These thunderstorms will push into southern WA by the evening, but much of the energy will begin to curl off to the west. This should reduce the amount of forcing that enters the region with this wave and is expected to result in thunderstorms diminishing in intensity by this time. /SVH Tues through Sunday: The Thurs/Fri ejection of the upper trough still looks like the main focus as far as any widespread thunder threat and post- frontal windy wx. The vast majority of model guidance remain similar with digging the upper low S down the Pac Nw coast. The primary challenge will be dealing with the ejection of this low NE into Ern Wa and N Idaho Thurs & Fri. The ECMWF is now only slightly faster to eject this wave NE, and both the GFS and ECMWF continue with the trend of taking the low nearly straight north across Wrn Wa and the Cascades. This would mean the highest threat of thunder would be along and near the Cascades, definitely NOT where we would prefer given the current wildfires that may be enhanced by gusty outflow, not to mention new fire starts. And if this Cascades pcpn is slow to exit, another issue COULD be debris flows on current and recent burns. Though this is the most important part of the fcst, it may not be the most challenging part. As the wave digs S down the coast, Ern Wa and N Idaho will be in a prolonged southerly fetch of increasing moisture within a high- amplitude thermal ridge. This will not only help to destabilize the sfc, but will also complicate matters since there are at least three nocturnal subtle waves that move N into Ern Wa through Wed. All of these accompany weak to moderate convective/potential instability not rooted at the surface that could produce a few overnight lightning strikes. Overnight low temps will be very mild. And within the aforementioned thermal ridge, Spokane may not be the only place that tops record high temps Wed.bz && .AVIATION... 12Z TAFS: A potent shortwave trough of lower pressure will push across the region after 20Z. The atmosphere become increasingly unstable at this time with scattered thunderstorms across much of extreme eastern WA and into the ID panhandle. The focus of this thunderstorm activity is expected to remain east of a line from KMWH to KOMK. Timing of storms at KLWS and KPUW is expected between 20-00Z and between 23-04Z at KGEG, KSFF and KCOE. Primary concerns with thunderstorms will be for strong outflow winds and frequent lightning strikes. Visibility may also be reduced at the TAF sites from blowing, especially at the KGEG, KSFF and KMWH TAF sites. Confidence of thunderstorms this afternoon and evening is moderate. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 91 64 97 66 100 69 / 20 40 10 20 10 10 Coeur d`Alene 92 59 97 63 99 65 / 30 40 10 20 10 10 Pullman 90 55 96 60 98 63 / 40 30 10 20 20 10 Lewiston 96 65 102 69 106 71 / 40 20 20 20 20 10 Colville 94 60 99 59 104 59 / 20 20 10 20 20 20 Sandpoint 90 54 95 59 98 57 / 20 30 10 20 20 20 Kellogg 92 56 96 60 98 63 / 30 50 10 20 10 20 Moses Lake 94 63 100 64 103 66 / 10 20 10 20 10 10 Wenatchee 94 72 99 70 102 75 / 10 30 10 20 20 10 Omak 96 66 101 66 102 67 / 20 30 10 20 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...FIRE Weather Watch from 2 PM PDT this afternoon through late tonight for Northern and Central Idaho Panhandle (Zone 101). WA...FIRE Weather Watch from 2 PM PDT this afternoon through late tonight for East Washington Palouse and Spokane Area (Zone 674). FIRE Weather Watch from this afternoon through late tonight for East Washington South Central Cascade Mountains (Zone 680)- East Washington South Central Cascade Valleys (Zone 676). && $$
AREA FORECAST DISCUSSION
NWS PORTLAND OR
300 AM PDT MON AUG 10 2015 .SYNOPSIS...A LOW PRESSURE SYSTEM CENTERED OFF THE WASHINGTON COAST ALONG 130W EARLY THIS MORNING WILL CONTINUE MOVING SOUTHWARD OFF THE COAST...REACHING WEST OF THE NORTHERN CALIFORNIA COAST TUESDAY... THEN LIFTING OUT TO THE NORTHEAST AND THROUGH THE PACIFIC NORTHWEST THURSDAY AND FRIDAY. LOOK FOR OCCASIONAL SHOWERS OR THUNDERSTORMS IN THE AFTERNOONS AND EVENINGS DURING THE WEEK THAT MAY DRIFT OUT INTO THE VALLEYS AND THE COAST RANGE AT TIMES IN THE EVENINGS AND OVERNIGHT PERIODS. THE BEST CHANCE OF MORE WIDESPREAD SHOWERS OR THUNDERSTORMS IS LATER THURSDAY INTO FRIDAY AS THE LOW MOVES ONSHORE AND INLAND. WARMER AND DRY WEATHER IS EXPECTED TO RETURN NEXT WEEKEND. && .SHORT TERM...AS ADVERTISED...A CLOSED UPPER LOW WAS LOCATED OFF THE WASHINGTON COAST EARLY THIS MORNING CENTERED ALONG 130W. THE LOW WILL CONTINUE TO MOVE SOUTHWARD AND WILL BE CENTERED OFF THE OREGON COAST THIS AFTERNOON. THIS WILL CAUSE THE FLOW ALOFT TO BACK TO MORE SOUTHERLY TODAY...WARMING THE AIR MASS SOME. A BAROCLINIC OR FRONTAL ZONE HAS DEVELOPED OVER THE COASTAL WATERS BUT WILL HAVE TROUBLE MAKING MUCH INLAND PROGRESSION TODAY DUE TO THE SOUTHERLY FLOW ALOFT. THE COAST MIGHT GET BRUSHED WITH A FEW SHOWERS THOUGH. TEMPS INLAND TODAY WILL BE IN AT LEAST THE MID 80S AND POSSIBLY THE UPPER 80S. THE MODELS ALSO INDICATE THAT CONVECTION WILL DEVELOP OVER THE CASCADES AND FOOTHILLS THIS AFTERNOON AS A SHORT WAVE LIFTS NORTH ALONG THE EASTERN PERIPHERY OF THE OFFSHORE LOW...AND POSSIBLY EVEN OVER THE VALLEY OR INTO THE COAST RANGE LATER TODAY OR TONIGHT. THERE IS SOME UPPER JET SUPPORT FOR THIS CONVECTION TODAY AND THIS EVENING...AND SOME OF THE THUNDERSTORMS THAT DO DEVELOP COULD BE STRONGER THAN WHAT WE NORMALLY SEE. AS THE LOW CONTINUES TO MOVE SOUTH TONIGHT INTO TUESDAY...THE UPPER FLOW TURNS SOUTHEASTERLY AND WILL CAUSE ANY RESIDUAL ACTIVITY TO DRIFT OUT OVER THE VALLEYS AND TOWARD THE COAST RANGE TONIGHT. THINGS SHOULD SETTLE DOWN BY TUESDAY MORNING AS THE LAST OF THE MOISTURE DRIFTS OUT OVER THE COASTAL WATERS AND WEAKENS. THE LOW WILL CONTINUE TO MOVE SOUTH AND BE CENTERED SOUTH OF 40N AND WEST OF 130W OFF THE NORTHERN CALIFORNIA COAST BY LATER TUESDAY. THERE IS AGAIN A CHANCE OF THUNDER OVER THE CASCADES TUESDAY AFTERNOON THAT COULD DRIFT OUT OVER THE VALLEYS TUESDAY NIGHT UNDER PREVAILING SOUTHEAST FLOW ALOFT. THE AIR MASS WILL CONTINUE TO BE QUITE WARM TO THE EAST AND NORTHEAST OF THE LOW ON TUESDAY...AND INLAND TEMPS MAY APPROACH 90 ON TUESDAY. THE LOW MEANDERS OFF THE NORTHERN CALIFORNIA COAST WEDNESDAY. THE MODELS SUGGEST THAT AFTER THE RESIDUAL CONVECTIVE ACTIVITY FROM TUESDAY NIGHT DRIFTS NORTHWEST AND AWAY FROM OUR AREA WEDNESDAY MORNING...THAT ACTIVITY WILL BE LESS WEDNESDAY AFTERNOON AND EVENING. HAVE KEPT A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDER OVER THE CASCADES. THE MODELS SHOW OUR CURRENT SOUTH WINDS ALONG THE COAST THIS MORNING TURNING NORTHERLY IN THE WAKE OF THE LOW LATER TODAY AND TONIGHT. THE WINDS THEN TURN BACK TO SOUTHERLY AGAIN WEDNESDAY AS A SOUTHERLY WIND REVERSAL AND STRATUS SURGE MOVES UP THE COAST IN RESPONSE TO SHORT WAVE MOVING NORTH ALONG THE COAST. THIS SHOULD BUILD THE MARINE LAYER ALONG THE COAST AND IS THE FIRST STEP IN STARTING TO INCREASE THE ONSHORE FLOW. WE MAY SEE SOME PATCHY DRIZZLE IN THIS STRENGTHENING MARINE LAYER. THE SOUTHERLY WINDS THAT DEVELOP ALONG THE COAST WEDNESDAY MAY BE A BIT BREEZY AS WELL. TOLLESON .LONG TERM...THE LOW THAT DROPPED SOUTH ALONG THE COAST DURING THE EARLY PART OF THE FORECAST IS EXPECTED TO APPROACH THE OREGON COAST THURSDAY AND MOVE NORTHEAST ACROSS SOUTHWEST WASHINGTON AND NORTHWEST OREGON THURSDAY NIGHT AND EARLY FRIDAY. THIS WILL BRING AN INCREASED CHANCE OF SHOWERS...WITH A FEW THUNDERSTORMS POSSIBLE DUE TO INSTABILITY FROM THE COLD POOL ALOFT WITH THE UPPER LOW. THIS WILL ALSO BRING A STRONG SOUTHWEST MARINE PUSH TO OUR FORECAST AREA WITH WIDESPREAD CLOUDS AND COOLER TEMPS THROUGH FRIDAY. THE MODELS ARE THEN GENERALLY DRY FOR THE WEEKEND BUT DIFFER ON HOW WARM IT WILL BE...AND HAVE OPTED FOR A BLEND OF THE MODELS FOR NOW AS NORTHWEST FLOW ALOFT PREVAILS. THE MODELS HINT AT ANOTHER TROUGH DROPPING DOWN FROM THE NORTHWEST EARLY NEXT WEEK...BUT THE GFS IS STRONGER AND DIGS IT MORE SOUTHWARD WHILE THE ECMWF KEEPS THE MAIN PART OF THE TROUGH SLIDING BY TO OUR NORTH. HAVE OPTED TO STAY DRY FOR NOW BUT WITH SOME ONSHORE FLOW CONTINUING/INCREASING. TOLLESON && .AVIATION...VFR CONDITIONS WITH CIGS BETWEEN 10K-25K FT WILL GENERALLY PERSIST NEXT 24 HRS FOR INLAND SITES. MVFR AND IFR CIGS ALONG THE COAST WILL CONTINUE TONIGHT UNDER SOUTH-SOUTHWEST FLOW...BUT CIGS APPEAR TO BE RISING PARTICULARLY ALONG THE N OR COAST. EXPECT MOSTLY MVFR CIGS ON THE COAST THROUGH MORNING. FOR MON...CHANCE OF TSRA FROM THE COAST RANGE EASTWARD IN THE LATE AFTERNOON AND EVENING BUT WITH DISAGREEMENT AMONG MODELS...WILL LEAVE OUT MENTION FOR NOW. KPDX AND APPROACHES...VFR NEXT 24 HOURS. SLIGHT CHANCE SHRA OR TSRA MAINLY AFTER 00Z. BOWEN && .MARINE...NOT MUCH CHANGE TO THE FORECAST WITH WINDS BELOW ABOUT 15 KTS AND SEAS AROUND 4 FT THROUGH MUCH OF THE WEEK. WEAK SURFACE LOW CURRENTLY SITS OFF THE WASHINGTON COAST OVER THE OFFSHORE WATERS BUT BIGGEST IMPACT WILL BE VARIABLE WIND DIRECTION WITH A VARYING DEGREE OF SOUTH OR WEST COMPONENT IN THE WIND AS THE LOW SLOWLY DRIFTS THROUGH THE REGION OVER THE NEXT 48 HOURS. SURFACE HIGH PRESSURE BUILDS OVER THE NE PACIFIC STARTING MIDWEEK AND ESPECIALLY INTO LATE WEEK. THE NEXT THREAT FOR SMALL CRAFT ADVISORY STRENGTH WINDS LOOKS TO BE AROUND FRIDAY AS THERMAL LOW PRESSURE DEEPENS ALONG THE N CALIFORNIA/SW OREGON COAST. HOWEVER MODELS HAVE AT LEAST TEMPORARILY BACKED OFF ON WINDS LATE WEEK.BOWEN && .PQR WATCHES/WARNINGS/ADVISORIES... OR...RED FLAG WARNING FROM NOON TODAY TO 11 PM PDT TUESDAY FOR CENTRAL OREGON CASCADE FOOTHILLS-MT. HOOD NATIONAL FOREST WEST OF CASCADE CREST-NORTH OREGON CASCADE FOOTHILLS- WILLAMETTE NATIONAL FOREST. WA...FIRE WEATHER WATCH FROM 1 PM PDT THIS AFTERNOON THROUGH LATE TONIGHT FOR EXTREME SOUTH WASHINGTON CASCADES AND FOOTHILLS. PZ...NONE. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
Area Forecast Discussion National Weather Service Spokane WA 258 AM PDT MON AUG 10 2015 .SYNOPSIS... Hot weather will return for most of the work week with a continued chance of thunderstorms. Some storms may produce strong winds this afternoon and evening, mainly from the Northeast Blue Mountains and Camas Prairie areas and propagating as far north as the Northeast Mountains and Northern Panhandle. A few record high temperatures may be set Wednesday. A cold front thursday will bring another active thunderstorm threat along with cooler temperatures by next weekend. && .DISCUSSION... ...STRONG WINDS POSSIBLE WITH THUNDERSTORMS TODAY... Today and Tonight: There are a couple of vorticity maximums to watch out for today. Both are swinging around the base of a deep upper level low pressure system off of the coast of WA. The first, and more likely to have the bigger impact, is a shortwave disturbance currently pushing into northern California early this morning. This disturbance is progged to quickly push northeast and begin to push up into the region between noon and 200 PM PDT. Before we do see the effects of this disturbance, we will see some lingering light shower activity mainly across the northern half of the forecast area through this morning. Satellite imagery indicates a lot of clearing occurring behind these showers. This will set up a situation where there should be plenty of sunshine for the atmosphere to destabilize by the afternoon before the disturbance over California makes it this far north. Moisture will increase across the region with dew points expected to remain right around 50 degrees. This will set up the ingredients for a decent amount of surface based CAPE to work with. Models are generally showing somewhere in the neighborhood of 500-1500 J/KG of surface based CAPE across the eastern half of the forecast area; this generally includes areas east of a line extending from Ritzville to Republic. Thunderstorms are expected to initiate over northeast OR and in the southern Panhandle in the early afternoon and the push northward into southeastern WA and into the central Panhandle through the afternoon hours. Main threats with the thunderstorms will be for strong outflow winds. The WRF-NMM, WRF-ARW and HRRR models all show a signal of a gust front emanating northward from the convection. These models have also been consistent with this idea over the past few runs. I increase winds across the Palouse, into the basin, the Spokane- Coeur d`Alene corridor and into the northern mtns and ID Panhandle. These winds may also result in blowing dust with reduced visibility possible across portions of I-90 and highway 2. Forecast confidence in the strong outflow winds and blowing dust is only moderate and there is some bust potential as all the ingredients need to come together. With that said, there is enough evidence that concerns are increasing. Thunderstorms are also expected to include frequent cloud to ground lightning strikes. There will be some rain with the heavier thunderstorm cores, but, away from these course, there will also be a lot of evaporation that takes place. This should result in a higher potential for new fire starts from lightning strikes. The Fire Weather Watch will remain as is for now and will be reassessed later in the morning. A second disturbance will push up more across central OR in the wake of the first. This piece of energy will spark off more thunderstorms that will push northward through the late afternoon hours. These thunderstorms will push into southern WA by the evening, but much of the energy will begin to curl off to the west. This should reduce the amount of forcing that enters the region with this wave and is expected to result in thunderstorms diminishing in intensity by this time. /SVH Tues through Sunday: The Thurs/Fri ejection of the upper trough still looks like the main focus as far as any widespread thunder threat and post- frontal windy wx. The vast majority of model guidance remain similar with digging the upper low S down the Pac Nw coast. The primary challenge will be dealing with the ejection of this low NE into Ern Wa and N Idaho Thurs & Fri. The ECMWF is now only slightly faster to eject this wave NE, and both the GFS and ECMWF continue with the trend of taking the low nearly straight north across Wrn Wa and the Cascades. This would mean the highest threat of thunder would be along and near the Cascades, definitely NOT where we would prefer given the current wildfires that may be enhanced by gusty outflow, not to mention new fire starts. And if this Cascades pcpn is slow to exit, another issue COULD be debris flows on current and recent burns. Though this is the most important part of the fcst, it may not be the most challenging part. As the wave digs S down the coast, Ern Wa and N Idaho will be in a prolonged southerly fetch of increasing moisture within a high- amplitude thermal ridge. This will not only help to destabilize the sfc, but will also complicate matters since there are at least three nocturnal subtle waves that move N into Ern Wa through Wed. All of these accompany weak to moderate convective/potential instability not rooted at the surface that could produce a few overnight lightning strikes. Overnight low temps will be very mild. And within the aforementioned thermal ridge, Spokane may not be the only place that tops record high temps Wed.bz && .AVIATION... 06Z TAFS: A closed upper level low pressure system will remain positioned off of the Washington Coast. Disturbance rotating ahead of this low will move north and northeast and bring increased mid level clouds along with some showers and thunderstorms overnight tonight into Monday morning. Additional disturbances will bring more potential for showers and thunderstorms after 23Z Monday into the evening that could bring a better chance of gusty wind. All TAF sites are expected to remain VFR through 06Z tuesday. /Pelatti && .PRELIMINARY POINT TEMPS/POPS... Spokane 91 64 97 66 100 69 / 20 40 10 20 10 10 Coeur d`Alene 92 59 97 63 99 65 / 30 40 10 20 10 10 Pullman 90 55 96 60 98 63 / 40 30 10 20 20 10 Lewiston 96 65 102 69 106 71 / 40 20 20 20 20 10 Colville 94 60 99 59 104 59 / 20 20 10 20 20 20 Sandpoint 90 54 95 59 98 57 / 20 30 10 20 20 20 Kellogg 92 56 96 60 98 63 / 30 50 10 20 10 20 Moses Lake 94 63 100 64 103 66 / 10 20 10 20 10 10 Wenatchee 94 72 99 70 102 75 / 10 30 10 20 20 10 Omak 96 66 101 66 102 67 / 20 30 10 20 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...FIRE Weather Watch from 2 PM PDT this afternoon through late tonight for Northern and Central Idaho Panhandle (Zone 101). WA...FIRE Weather Watch from 2 PM PDT this afternoon through late tonight for East Washington Palouse and Spokane Area (Zone 674). FIRE Weather Watch from this afternoon through late tonight for East Washington South Central Cascade Mountains (Zone 680)- East Washington South Central Cascade Valleys (Zone 676). && $$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1046 AM CDT MON AUG 10 2015 .UPDATE... A 500MB TROUGH WILL SWING THROUGH THE GREAT LAKES REGION TODAY AND TONIGHT. VORTICITY ADVECTION WITH AN EMBEDDED SHORTWAVE WILL LEAD TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS SOUTH CENTRAL AND SOUTHEAST WI NOW THROUGH 3 PM. THE 14Z HRRR RUN IS SHOWING THIS BUT LOOKS A LITTLE OVERDONE. RADAR IS ALREADY SHOWING A FEW MORE SHOWERS DEVELOPING ALREADY. THERE IS MODERATE INSTABILITY IN PLACE OVER SOUTHERN WI WITH UP TO 1000 J/KG OF SURFACE-BASED CAPE. SHEAR IS MINIMAL... SO NOT EXPECTING ANY SEVERE THUNDERSTORMS- JUST SCATTERED STORMS WITH HEAVY DOWNPOURS. STORMS ARE SLOW-MOVING SO UP TO A QUARTER INCH OF RAIN WOULD BE POSSIBLE WITH A SINGLE STORM. THE SURFACE COLD FRONT ALREADY WENT THROUGH THE AREA EARLY THIS MORNING... BUT THE UPPER LEVEL COLD FRONT WILL NOT CLEAR SOUTHERN WI UNTIL LATE TONIGHT. THERE IS ONE MORE SHORTWAVE TO CROSS THE AREA OVERNIGHT... BUT THAT SHOULD COME THROUGH DRY. THE COLUMN WILL BE DRYING OUT AND IT IS ALSO COMING THROUGH DURING A DIURNALLY UNFAVORABLE TIME OF DAY FOR CONVECTION. && .AVIATION/18Z TAFS/... SCATTERED SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS SOUTH CENTRAL AND SOUTHEAST WI LATE THIS MORNING AND WILL PERSIST THROUGH MID AFTERNOON. THESE ARE DUE TO THE PASSAGE OF AN UPPER LEVEL COLD FRONT AND THE DEVELOPMENT OF A LAKE BREEZE FRONT. AREAS OF MVFR CIGS WILL BE POSSIBLE BY THE MIDDLE TO LATE MORNING WITH THE INITIAL CUMULUS DEVELOPMENT BUT LIFT TO 3.5-5.0 KFT THROUGH THE AFTERNOON. COLD AND DRY AIR ADVECTION TO PREVAIL TNT ON NLY WINDS SO FOG POTENTIAL IS VERY LOW. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...MRC TODAY/TONIGHT AND AVIATION/MARINE...GEHRING TUESDAY THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
418 AM MDT MON AUG 10 2015 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 222 AM MDT MON AUG 10 2015 TRANQUIL WEATHER CONDITIONS TO START THE FORECAST PERIOD WITH MOSTLY CLEAR SKIES IN PLACE ACROSS THE REGION. THERE IS STILL THE POTENTIAL FOR PATCHY FOG TO DEVELOP ALONG AND EAST OF THE LARAMIE RANGE GIVEN WEAK UPSLOPE AND EXCELLENT LOW-LEVEL SATURATION INDICATED BY NAM/GFS BUFKIT SOUNDINGS. THE HRRR HAS NOT BEEN OVERLY SUPPORTIVE...BUT WILL MAINTAIN MENTION OF FOG THROUGH ABOUT 15Z...WHEN BOUNDARY LAYER RHS SHOULD DECREASE. A STALLED N-S ORIENTED COLD FRONT ALONG THE LARAMIE RANGE WILL SUPPORT CONTINUED LOW-LEVEL UPSLOPE TODAY. EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE MOUNTAINS AFTER 21Z...AND MOVE EAST ONTO THE PLAINS THROUGH THE EVENING. CANNOT ENTIRELY RULE OUT A STRONGER STORM OR TWO IF THE GFS VERIFIES WITH SBCAPE NEAR 1000 J/KG ALONG THE I-80 CORRIDOR BETWEEN CYS-SNY...ESPECIALLY GIVEN 0 TO 6 KM SHEAR IN EXCESS OF 35 KTS. SHOULD NOT BE LOOKING AT ANYTHING SEVERE THOUGH. A TYPICAL AUGUST WEATHER PATTERN WILL CONTINUE THROUGH MID WEEK WITH UPPER-LEVEL RIDGING THE DOMINANT FEATURE. SOUTHWEST FLOW ALOFT WILL YIELD A PERSISTENT FEED OF MONSOONAL MOISTURE...GIVING WAY TO DAILY CHANCES FOR CONVECTION GENERALLY ALONG AND WEST OF THE LARAMIE RANGE ON TUESDAY AND WEDNESDAY AFTERNOONS. A GRADUAL WARMING TREND CAN BE EXPECTED AS RIDGING STRENGTHENS...AND H7 TEMPS INCREASE TO NEAR +16 DEG C BY 00Z THU. SHOULD SEE MORE WIDESPREAD 90S FOR AFTERNOON HIGHS BY THE END OF THE PERIOD. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 222 AM MDT MON AUG 10 2015 ALL MEDIUM TO LONG RANGE MODELS SHOW THE UPPER LEVEL HIGH...CENTERED NEAR THE FOUR CORNERS REGION...DOMINATING THE WEATHER PATTERN LATE THIS WEEK AND INTO NEXT WEEKEND. THE HIGH SHOWS SOME SIGNS OF RETROGRADING OR WEAKENING BY NEXT WEEKEND...AS ENERGY FROM THE NORTHERN PACIFIC DIVES SOUTHEAST INTO THE NORTHWEST UNITED STATES. ANY NOTICEABLE CHANGES TO THE PATTERN ARE NOT EXPECTED TO OCCUR OVER THE NEXT 7 DAYS THOUGH...SO EXPECTED PERSISTENT SOUTHWEST FLOW ALOFT AND ADVECTION OF MONSOON MOISTURE LATE THIS WEEK AND NEXT WEEKEND. HIGH TEMPERATURES WILL BE ABOVE NORMAL THROUGH SATURDAY WITH READINGS IN THE 80S TO LOW 90S ACROSS MOST OF THE AREA. PORTIONS OF WESTERN NEBRASKA AND FAR EASTERN WYOMING WILL LIKELY REACH THE MID TO UPPER 90S ON FRIDAY AS 700MB TEMPERATURES PEAK BETWEEN 15C TO 18C. WITH PW/S INCREASING TO OVER ONE INCH ACROSS THE FRONT RANGE...THERE WILL BE PLENTY OF MOISTURE FOR SHOWERS AND TSTORMS TO DEVELOP OVER THE HIGHER TERRAIN. NOT CONFIDENT ON THE COVERAGE AT THIS TIME...BUT SOME OF THESE TSTORMS MAY CONTAIN VERY HEAVY RAINFALL. IN ADDITION...SHOWERS AND TSTORMS WILL NOT MOVE ALL THAT MUCH THROUGH EACH AFTERNOON. THUS THERE IS SOME CONCERN FOR FLASH FLOODING. KEPT POP BETWEEN 20 TO 30 PERCENT FOR THE HIGH VALLEYS AND HIGH PLAINS...WITH VALUES CLOSER TO 50 PERCENT IN THE MOUNTAINS. SEVERE TSTORMS APPEAR UNLIKELY AT THIS TIME DUE TO THE LACK OF SHEAR ACROSS THE AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH MONDAY NIGHT) ISSUED AT 300 AM MDT MON AUG 10 2015 MVFR CIGS AND PATCHY FOG IS EXPECTED EARLY THIS MORNING BEFORE LIFTING BY 15Z OVER MOST TERMINALS. LOW CLOUDS MAY LINGER THROUGH THE DAY OVER KSNY...KAIA...AND KCDR HOWEVER. ANOTHER ROUND OF SHOWERS AND TSTORMS ARE EXPECTED MAINLY OVER SOUTHEAST WYOMING THIS AFTERNOON AND INTO THIS EVENING. && .FIRE WEATHER... ISSUED AT 222 AM MDT MON AUG 10 2015 NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. NON-CRITICAL CONDITIONS ARE EXPECTED WITH WIND GUSTS EXPECTED TO REMAIN BELOW 25 MPH AND HUMIDITIES GENERALLY ABOVE 20 PERCENT WITH GOOD TO EXCELLENT RECOVERY OVERNIGHT. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS COULD OCCUR EACH AFTERNOON THROUGH THE WEEK. THE MAIN HAZARD FROM THESE STORMS WILL BE GUSTY AND ERRATIC WINDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CLH LONG TERM...TJT AVIATION...TJT FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
942 AM MST MON AUG 10 2015 .SYNOPSIS... SOUTHERLY FLOW ALOFT WILL GRADUALLY INCREASE MOISTURE LEVELS ACROSS THE REGION TODAY THROUGH TUESDAY...WITH TUESDAY AFTERNOON AND EVENING SEEING THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS SOUTH CENTRAL ARIZONA. VERY STRONG HIGH PRESSURE ALOFT BUILDING INTO THE REGION FROM THE EAST WILL THEN BRING MUCH ABOVE NORMAL TEMPERATURES AND REDUCE THUNDERSTORM CHANCES FROM WEDNESDAY ONWARD INTO SATURDAY...WITH COOLER TEMPERATURES AND BETTER CHANCES FOR STORMS RETURNING FROM SUNDAY ONWARD INTO EARLY NEXT WEEK. && .DISCUSSION... DEBRIS CLOUDINESS PERSISTS THIS MORNING ACROSS EAST-CENTRAL AZ BUT IS SHOWING SIGNS OF BREAKING APART. HIGH-RES WRFS ARE EXHIBITING SOMEWHAT MORE VARIABILITY THIS MORNING IN THE PLACEMENT OF THE AFTERNOON CONVECTION...THOUGH THE CONSENSUS IS THAT ACTIVITY WILL BE MOST LIKELY FROM PHOENIX EASTWARD. LATEST RUNS OF THE HRRR INDICATE THAT THE MORNING CLOUDS WILL INHIBIT CONVECTION...SUGGESTING ONLY ISOLATED STORMS LATE THIS AFTERNOON...MAINLY ACROSS NORTHERN GILA COUNTY. SHORT-TERM UPDATES TO THE FORECAST ARE NEEDED THIS MORNING...MAINLY TO ACCOUNT FOR THE DELAYED RISE IN TEMPERATURES. OTHERWISE...THE FORECAST REMAINS ON TRACK. && .PREVIOUS DISCUSSION... IT NOW APPEARS THAT TUESDAY WILL LIKELY BE THE MOST ACTIVE DAY...AS THE FLOW ALOFT BECOMES SOUTHERLY THROUGH THE WHOLE COLUMN WITH LESS CLOUDINESS LIKELY ON TUESDAY MORNING THEN WHAT WE ARE SEEING TODAY...WITH SOME DECENT MID-LEVEL SHEAR PERHAPS ENHANCING THE THUNDERSTORM INTENSIFY/COVERAGE...AND AT LEAST SOME STORM ACTIVITY WORKING ITS WAY INTO SW AZ. WEDNESDAY THROUGH SATURDAY... IT NOW LOOKS INCREASINGLY LIKELY THAT WE WILL SEE SOME VERY HOT TEMPERATURES DURING THIS PERIOD AS THE MAIN LONG-WAVE PATTERN RE- ADJUSTS ITSELF OVER NORTH AMERICA...WITH RATHER DEEP TROFING DROPPING DOWN INTO THE GREAT LAKES/NE US...AND THE MAIN UPPER RIDGE AXIS BEING FORCED WESTWARD OVER THE DESERT SW. EVEN THOUGH OUR MID/UPPER-LEVEL FLOW IS EXPECTED TO REMAIN MAINLY FROM A SE-LY DIRECTION DURING THIS PERIOD...WHICH NORMALLY IS THE BEST DIRECTION FOR MONSOON MOISTURE TO BE IMPORTED INTO THE REGION...THE UPPER HIGH CENTER THAT IS FORECAST TO BUILD OVER OUR REGION IS EXPECTED TO BE QUITE STRONG...WITH 500MB HEIGHTS RISING INTO THE 596-598DM RANGE BY THU-FRI. THIS UPPER HIGH CENTER...WHICH HAS BEEN CENTERED OVER THE GULF COAST REGION THE LAST FEW DAYS...HAS BROUGHT THAT REGION VERY HOT AND DRY CONDITIONS...WITH HIGHS APPROACHING OR EXCEEDING 100 DEGREES AT MANY LOCATIONS...INCLUDING HOUSTON AND NEW ORLEANS. STRONG SUBSIDENCE ALOFT HAS COMPLETELY SHUT DOWN THE CONVECTION THAT NORMALLY KEEPS HIGHS DOWN IN THE LOW-MID 90S AT THESE COASTAL LOCATIONS...AND IT APPEARS THAT THIS SUBSIDENCE IS HEADED OUR WAY...AS INDICATED ON THE LATEST FORECAST SOUNDINGS. THUS...IT APPEARS THAT THUNDERSTORM ACTIVITY WILL BE NOTICEABLY REDUCED DURING THIS PERIOD...WITH MOST ACTIVITY BEING CONFINED TO THE HIGHER TERRAIN OF SOUTH-CENTRAL AND SW AZ. THIS LACK OF CONVECTIVE ACTIVITY/INCREASED SUNSHINE ALONG WITH VERY WARM AIR ALOFT (500MB TEMPS IN THE -3C TO -4C RANGE) IS ALSO EXPECTED TO ALLOW OUT TEMPERATURES TO RISE WELL ABOVE NORMAL...WITH WIDESPREAD READINGS IN THE 110-115F RANGE ACROSS THE LOWER DESERTS. THESE VERY HOT DAYS ALONG WITH NIGHTTIME LOWS NEAR 90 AT THE WARMER URBAN LOCATIONS MAKES THE ISSUANCE OF HEAT PRODUCTS LATER THIS WEEK VERY LIKELY...ESPECIALLY FOR THE THU-FRI TIME PERIOD. SUNDAY AND MONDAY... ALTHOUGH SOME MODEL DISAGREEMENT DOES CROP UP DURING THIS PERIOD...IT APPEARS LIKELY THAT THE RIDGING OVER THE DESERT SOUTHWEST WILL BEGIN TO WEAKEN...WITH COOLER TEMPERATURES AND A BETTER CHANCE FOR THUNDERSTORMS RETURNING TO THE REGION. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... A REMNANT CIRCULATION CENTER NEAR TUCSON WILL ROTATE THROUGH THE PHOENIX AREA THIS MORNING. AT THIS POINT IT APPEARS THE ONLY IMPACT WILL BE INCREASED MID LEVEL CLOUDS AND POSSIBLY A FEW SPRINKLES...BUT THAT`S ABOUT IT. LOOKING AHEAD TO THIS AFTERNOON...STORMS ARE POSSIBLE SOUTH/EAST OF PHOENIX BUT ARE EXPECTED TO DISSIPATE BEFORE REACHING ANY OF THE PHOENIX TERMINALS. MOST LIKELY IMPACT WOULD BE A MID EVENING SOUTHEASTERLY OUTFLOW SOME TIME BETWEEN 03Z-06Z. WILL LEAVE ALL OTHER WEATHER OUT OF THE TAFS. SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... DISTANT HIGH CLOUDS SHOULD BE THE ONLY IMPACT AT BOTH SE CA SITES. WINDS SHOULD BE LIGHT /CAN`T RULE OUT AN OCCASIONAL LATE DAY GUST/ AND FOLLOW DIURNAL TENDENCIES. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... WEDNESDAY THROUGH SUNDAY... MONSOON MOISTURE WILL LINGER OVER THE REGION WEDNESDAY BEFORE SOME DRIER AIR BEGINS TO ADVECT INTO THE AREA. SLIGHT CHANCES FOR STORMS WILL CONTINUE...BEFORE TAPERING OFF HEADING THROUGH THE LATE WEEK AND INTO THE EARLY WEEKEND. AS HUMIDITIES AND DEWPOINTS BEGIN TO SLOWLY DROP...TEMPERATURES WILL BEGIN TO WARM AND HEADING ABOVE SEASONAL NORMALS FOR THE END OF THE WEEK. WINDS WILL GENERALLY BE LIGHT THROUGH THE MAJORITY OF THE FORECAST PERIOD WITH PERIODS OF UPSLOPE AFTERNOON GUSTINESS. && .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...HIRSCH PREVIOUS DISCUSSION...PERCHA AVIATION...LEINS FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
346 PM MDT MON AUG 10 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 235 PM MDT MON AUG 10 2015 TSRA MOST NUMEROUS THIS AFTERNOON OVER THE PLAINS SOUTH OF THE ARKANSAS RIVER...THOUGH AN ISOLATED CELL OVER TELLER AND EL PASO COUNTIES EARLIER IN THE DAY MANAGED TO PRODUCE FLASH FLOODING OVER WESTERN PORTIONS OF COLORADO SPRINGS AND THE EASTERN EDGE OF THE WALDO CANYON BURN SCAR. MAIN QUESTION FOR TONIGHT WILL REVOLVE AROUND LOCATION OF HEAVIER RAINFALL AND HOW LATE WILL STORMS PERSIST INTO TUE MORNING. 19Z/20Z RUNS OF THE HRRR BRING ANOTHER WAVE OF TSRA AND HEAVY RAIN THROUGH EL PASO COUNTY 00Z-02Z...THEN ACROSS PUEBLO COUNTY AND NORTHERN PORTIONS OF THE ARKANSAS VALLEY 02Z-05Z. 12Z VERSIONS OF THE NAM/NAM 4KM/NSSL WRF ON THE OTHER HAND...KEEP HEAVIEST RAINFALL MAINLY OVER THE MOUNTAINS OVERNIGHT...WITH FOCUS FOR MOST TSRA SHIFTING TOWARD THE SAN JUAN MOUNTAINS AFTER 06Z AS AREA OF DEEP TROPICAL MOISTURE OVER THE 4 CORNERS ROTATES NORTHEASTWARD. FORECAST LEANS A LITTLE TOWARD THE HRRR...AS LAPS CAPES ARE STILL ABOVE 1000 J/KG OVER THE EASTERN MOUNTAINS AND I-25 CORRIDOR...SUGGESTING ANOTHER BOUT OF TSRA IS POSSIBLE. CONSIDERED A FLASH FLOOD WATCH FOR EL PASO COUNTY FOR THIS EVENING AS HEAVY RAIN HAS FALLEN ACROSS THE REGION...THOUGH WITH HRRR SHIFTING AXIS OF STRONGER STORMS SOUTH FAIRLY QUICKLY...WILL REFRAIN FROM ISSUANCE AT THIS POINT. POCKETS OF HEAVY RAIN LOOK POSSIBLE FARTHER SOUTH OVER THE PLAINS...BUT MOST AREAS HAVE BEEN DRY ENOUGH LATELY TO TAKE AT LEAST A COUPLE HOURS OF HEAVER PRECIP. PRECIP SLOWLY WANES OVERNIGHT...BUT NEVER COMPLETELY COMES TO AN END...SO WILL KEEP SOME POPS GOING MANY AREAS INTO EARLY TUE MORNING. ON TUE...MOISTURE REMAINS IN PLACE...THOUGH HEIGHTS BEGIN TO BUILD SLIGHTLY AS UPPER HIGH STARTS ITS NORTHWARD EXPANSION. STILL APPEARS MOST LOCATIONS WILL SEE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ONCE AGAIN...THOUGH EXTENT OF OVERNIGHT CONVECTION AND POTENTIAL MCS OVER THE EASTERN PLAINS/NERN NM WILL LIKELY PLAY A ROLE IN AMOUNT OF CONVECTIVE COVERAGE...ESPECIALLY OVER THE PLAINS WHERE EARLY MORNING SHOWERS COULD LIMIT INSTABILITY. BROAD- BRUSH OF SCATTERED POPS LOOKS FINE...AND WITH MOISTURE LEVELS REMAINING RELATIVELY HIGH...LOCALLY HEAVY RAINFALL WILL AGAIN BE POSSIBLE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 235 PM MDT MON AUG 10 2015 UPPER RIDGE EXPANDS NORTHWARD WED-FRI...WITH THE UPPER LEVEL HIGH PRESSURE CENTER REMAINING ALONG THE CO/NM BORDER THROUGH THE PERIOD. TRAPPED MOISTURE UNDER THE HIGH WILL CONTINUE TO BE RECYCLED...WITH DAILY AFTERNOON/EVENING TSRA OVER THE MOUNTAINS...THOUGH COVERAGE MAY BECOME RATHER SPARSE WED/THU AS TEMPERATURES ALOFT WARM. PLAINS/VALLEY TSRA CHANCES LOOK FAIRLY LOW...THOUGH TOUGH TO RULE OUT A COUPLE STORMS DRIFTING AWAY FROM THE MOUNTAINS EACH DAY...ESPECIALLY ALONG AND WEST OF I-25. FORECAST HAS LOW POPS FOR ALL AREAS EACH DAY WED-FRI...WHICH MAY BE A LITTLE OVERDONE...BUT WILL RUN WITH FOR NOW. RIDGE FLATTENS SLIGHTLY FRI INTO THE WEEKEND...WHILE WEAK FRONT OOZES INTO THE EASTERN PLAINS LATE SUN. EXPECT A GRADUAL INCREASE IN TSRA CHANCE MOST LOCATIONS AS SLIGHTLY DEEPER MOISTURE MOVES IN FROM THE WEST...WHILE LOW LEVELS ON THE PLAINS MOISTEN AND WLY STEERING CURRENTS BECOME MORE FAVORABLE FOR STORMS TO MOVE ONTO THE PLAINS. TEMPS FROM WED INTO THE WEEKEND WILL REMAIN AT OR SLIGHTLY ABOVE SEASONAL AVERAGES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 235 PM MDT MON AUG 10 2015 SCATTERED TO NUMEROUS TSRA WERE OVER THE AREA THIS AFTERNOON WITH THE GREATEST COVERAGE OF STORMS SOUTH OF THE ARKANSAS RIVER. WHILE KPUB AND KCOS ARE CURRENTLY FREE OF CONVECTION AS OF 21Z...MESOSCALE MODELS INDICATE ANOTHER ROUND OF TSRA DROPPING SOUTH THROUGH KCOS 00Z-02Z...THEN THROUGH KPUB 01Z-03Z...SO WILL MAINTAIN A VCTS MENTION BOTH SITES UNTIL AROUND 03Z. AT KALS...WILL ALSO KEEP VCTS IN THE TAF INTO THE EVENING AS WELL...WITH STORMS ENDING 01-03Z. OVERNIGHT...TSRA MAY LINGER OVER THE PLAINS EAST OF I-25 MUCH OF THE NIGHT...WITH A THREAT OF SHOWERS AT TAF SITES 03Z-09Z. ON TUESDAY...TSRA WILL DEVELOP LATE MORNING OVER THE MOUNTAINS...THEN SPREAD TO LOWER ELEVATIONS...INCLUDING ALL TAF SITES IN THE AFTERNOON. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...PETERSEN AVIATION...PETERSEN
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS PEACHTREE CITY GA
152 PM EDT MON AUG 10 2015 .PREV DISCUSSION... /ISSUED 413 AM EDT MON AUG 10 2015/ SHORT TERM /TODAY THROUGH TUESDAY/... A COLD FRONT WILL IMPACT THE CWFA IN THE SHORT TERM PORTION OF THE FORECAST AREA. THE FRONT CURRENTLY STRETCHES FROM THE MID MISSISSIPPI RIVER VALLEY TO THE TENNESSEE VALLEY. THE BOUNDARY WILL SLIP SLOWLY SOUTH TODAY...AND CROSS MUCH OF THE FORECAST AREA ON TUESDAY. DEWPOINTS HAVE BEGUN TO CREEP UP ACROSS THE CWFA...A SIGN OF INCREASING LOW LEVEL MOISTURE. PRECIPITATION CHANCES WILL INCREASE TODAY AHEAD OF THE FROPA. HI-RES MODELS ARE SHOWING A RATHER ORGANIZED LINE OF SHOWERS AND THUNDERSTORMS MOVING SOUTH ACROSS NORTH AND CENTRAL GA THIS AFTERNOON. THE LOCAL WRF AND THE HRRR DO DIFFER A BIT...WITH THE WRF BEING LATER WITH THE CONVECTION. HAVE TRIED TO COMPROMISE ON TIMING. BOTH MODELS...HOWEVER...INDICATE VERY GOOD RAIN CHANCES ACROSS NORTHERN GA TODAY. SO...HAVE RAISED POPS TO LIKELY IN THAT REGION. ATMOS WILL BE FAVORABLE FOR STRONG TO ISOLATED SEVERE STORMS. GOOD SURFACE INSTABILITY WILL BE PRESENT...WITH AN ASSIST BY A SHORTWAVE DROPPING SOUTH IN THE MID LEVEL FLOW. MODELS CURRENTLY KEEP LAPSE RATES FAIRLY WEAK...BUT THE SHORTWAVE WILL PROVIDE SOME LIFT. COPIOUS CLOUD COVER SHOULD HELP LIMIT SEVERE STORM COVERAGE. THE MAIN FOCUS FOR TODAYS CONVECTION SHOULD BE ANY OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES FROM THE THUNDERSTORM COMPLEX CURRENTLY ACROSS THE MID MISSISSIPPI RIVER VALLEY. THE ACTUAL FRONTAL BOUNDARY WILL PROVIDE A FOCUS FOR STORMS TOMORROW. TEMPS SHOULD BE A FEW DEGREES COOLER THAN YESTERDAYS VALUES DUE TO THE INCREASED CLOUD COVER. TEMP/DEWPOINT VALUES REMAIN BELOW CRITICAL THRESHOLDS FOR A HEAT ADVISORY AT THIS TIME. NLISTEMAA LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... GUIDANCE IN DECENT AGREEMENT WITH AFOREMENTIONED FRONTAL BOUNDARY IN THE SHORT TERM LINGERING ACROSS THE SOUTHERN TIER OF THE CWA FOR TUESDAY NIGHT INTO WEDNESDAY...THEN FINALLY PUSHING JUST SOUTH OF THE AREA AND BECOMING MORE DIFFUSE THRU THE REST OF THE WORK WEEK. HAVE TRENDED CHANCE TO SLIGHT POPS ACCORDINGLY AND ADVECTION OF ABNORMALLY DRY AIR IN FROM THE NW WILL ALLOW FOR A RATHER PLEASANT WED AND THURS WITH SLIGHTLY BELOW NORMAL HIGHS AND RESULTANT AFTERNOON RH VALUES IN THE 40S. FOR FRIDAY INTO THE WEEKEND...A BROAD/WEAK AREA OF LOW PRESSURE LOOKS TO DEVELOP ACROSS THE NORTHERN GULF OF MEXICO ALLOWING FOR SOME LOW LEVEL MOISTURE TRANSPORT OFF THE ATLANTIC. HAVE CONTINUED TO ADVERTISE A RETURN OF SLIGHT TO LOW END CHANCE POPS FOR PORTIONS OF THE AREA...MAINLY FOR DIURNALLY DRIVEN CONVECTION. NO OTHER CLEAR FORCING MECHANISM LOOKS TO BE PRESENT SO NOT EXPECTING ANYTHING WIDESPREAD AND RATHER STAGNANT AIRMASS IN PLACE SO DEVELOPMENT SHOULD BE TYPICAL SUMMERTIME OUTFLOW DRIVEN. TEMPS SHOULD BE SLIGHTLY WARMER THAN MIDWEEK BUT CLOSE TO NORMAL OR SLIGHTLY BELOW WITH ENHANCED CLOUD COVERAGE. BAKER && .AVIATION... 18Z UPDATE... CURRENT RADAR SHOWS SCATTERED SHOWERS DEVELOPING AROUND ALL TAF SITES. A MORE ORGANIZED AREA OF SHOWERS AND THUNDERSTORMS WAS NOTED OVER NE AL AND MOVING ESE. HI-RES MODELS BRING TH MORE ORGANIZED CONVECTION TO THE NW ACROSS THE ATLANTA AREA TAF SITES BETWEEN 20- 24Z. WILL CONTINUE TO SHOW TEMPO TSRA 20-24Z FOR NOW... WITH VCSH HANDLING THE CURRENT SHOWERS UNTIL 20Z. SCATTERED SHOWERS MAY LINGER OVERNIGHT... WITH MVFR CIGS EXPECTED TO SETTLE IN OVER MOST TAF SITES BY 09Z TUE... THEN PERSIST THROUGH 15-16Z TUE. A PRE-FRONTAL TROUGH SHOULD PUSH SOUTH OF ATLANTA TAF SITES BY 17-18Z... WITH A DRIER NW FLOW SPREADING VFR CONDITIONS INTO THE AREA TUE AFTERNOON. //ATL CONFIDENCE...18Z UPDATE... MED CONFIDENCE ALL ELEMENTS. /39 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 90 72 89 71 / 40 40 30 30 ATLANTA 90 74 88 72 / 40 40 30 20 BLAIRSVILLE 84 67 83 63 / 60 40 30 10 CARTERSVILLE 90 71 88 68 / 60 40 30 20 COLUMBUS 93 76 91 74 / 40 30 40 40 GAINESVILLE 87 72 87 71 / 60 40 30 20 MACON 92 74 90 73 / 40 30 40 40 ROME 91 72 89 68 / 60 40 30 10 PEACHTREE CITY 91 72 89 70 / 40 30 30 30 VIDALIA 92 73 92 74 / 30 20 40 50 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
509 PM CDT MON AUG 10 2015 .MESOSCALE DISCUSSION... 349 PM CDT THREE LINES OF SHOWERS WITH EMBEDDED THUNDERSTORMS CONTINUE TO TRACK SOUTHWARD FROM CENTRAL WISCONSIN TO NORTHERN ILLINOIS. THE FIRST LINE...NOW EXTENDING FROM LONG POINT TO DE MOTTE...HAS LOST MUCH OF ITS STRENGTH AS THE OUTFLOW BOUNDARY HAS OUTRUN THE MAIN LINE OF STORMS. THIS OUTFLOW HAS SHOWN GUSTS OF 25KT AT IKK WITH SIMILAR VALUES EXPECTED FOR THE REMAINDER OF ITS LIFE IN THE CWA. SINCE THIS LINE HAS THE MOST UNTAPPED INSTABILITY TO WORK WITH...A FEW GIRTHY YET SUB-SEVERE STORMS ARE POSSIBLE. THE MIDDLE LINE OF STORM EXTENDING FROM BUFFALO TO NORTH CHICAGO IS CURRENTLY SHOWING THE MOST UPWARD GROWTH AND OUTFLOW INTERACTIONS. DOPPLER RADAR SHOWS NUMEROUS OUTFLOW WAVES FROM MULTIPLE PREVIOUS STORMS. THESE INTERACTIONS CAN ACT TO CREATE LOW LEVEL WIND SHEAR AND MAY PROMPT BRIEF FUNNEL CLOUD DEVELOPMENT. ONE CELL IN PARTICULAR FROM CAROL STREAM HEADED SOUTH TOWARD DOWNERS GROVE HAS SHOWN NEARLY 60 DBZ OF REFLECTIVITY ABOVE THE -20C LINE. 1 INCH HAIL IS NOT OUT OF THE QUESTION WITH CELLS SIMILAR TO THIS OVER THE NEXT 2-3 HOURS WHILE DAYTIME HEATING IS STILL ABUNDANT. EXPECT CONTINUED INTERACTIONS TO ALSO FUEL CELL GROWTH. IN THIS REGIME...EVEN VERTICALLY CHALLENGED CELLS MAY SHOW SIGNS OF BRIEF ROTATION...BUT WIDESPREAD TORNADIC ACTIVITY IS NOT ANTICIPATED. THE THIRD/NORTHERLY LINE MARKS A COLD FRONT WHERE DEWPOINT TEMPERATURES DROP ROUGHLY 10 DEGREES. THIS LINE HAS THE MOST SUFFICIENT FORCING MECHANISM...BUT LITTLE IN THE WAY OF INSTABILITY. THE FRONT WILL BE HALFWAY ACROSS THE CWA BY 23Z (MENDOTA TO PLAINFIELD TO GARY)...AT WHICH POINT THE LOSS OF DAYTIME HEATING IS EXPECTED TO CEASE REMAINING THUNDER CHANCES. THIS IS SUPPORTED BY THE EXPERIMENTAL HRRR THAT SUGGESTS ISOLATED LINGERING SHOWERS THROUGH 00Z. MM && .SHORT TERM... 237 PM CDT THROUGH TONIGHT... A SERIES OF SHORTWAVE TROUGHS CONTINUE TO TRACK SOUTHEAST ACROSS THE REGION GENERATING BANDS OF SHOWERS AND THUNDERSTORMS. THE FIRST WAVE IS CROSSING FAR SOUTHERN LAKE MICHIGAN PUSHING A BAND OF SHOWERS AND STORMS SOUTHWARD ALONG THE I-80 CORRIDOR AT THIS TIME WITH ANOTHER CLUSTER OUT OVER LAKE MICHIGAN. WITH THE MOVEMENT OF THE WAVE HAVING AN EASTWARD COMPONENT THE BETTER LARGER SCALE FORCING WILL BE SHIFTING AWAY FROM THE CURRENT BAND OF ACTIVITY ALONG I-80 SO THIS AREA MAY START TO FADE IN COVERAGE OVER THE NEXT COUPLE HOURS. IN ADDITION...OUTFLOW IS NOW OUTRUNNING THE CONVECTION SUPPORTING A DOWNWARD TREND. HOWEVER...WITH AN UNSTABLE AIRMASS IN PLACE THE OUTFLOW MAY GENERATE NEW STORMS SOUTH OF I-80 BUT THE EXITING OF THE UPPER FORCING SUGGESTS MORE ISOLATED COVERAGE TO ANYTHING ADDITIONAL. AREAS OF NORTHWEST INDIANA PROBABLY HAVE THE BEST CHANCE FOR RENEWED DEVELOPMENT FROM THIS FIRST WAVE THROUGH LATE AFTERNOON. ATTENTION TURNS TO A SECOND WAVE TRACKING ACROSS CENTRAL WISCONSIN WHICH IS GENERATING SCATTERED CONVECTION ACROSS MUCH OF SOUTHERN WISCONSIN. THIS ACTIVITY IS MORE DISJOINTED IN COVERAGE BUT WILL LIKELY CONTINUE INTO NORTHERN ILLINOIS INTO LATE AFTERNOON...WITH ADDITIONAL DEVELOPMENT ACROSS NORTHERN ILLINOIS IN THE MEANTIME. STORM ORGANIZATION WILL LIKELY BE A BIGGER CHALLENGE NORTH OF I-80 GIVEN THE PREVIOUS ACTIVITY BUT SOME BRIEF PULSING OF UPDRAFTS MAY PRODUCE SOME SMALL HAIL AND SOME SUB SEVERE WIND GUSTS. A SUBTLE COOL FRONTAL BOUNDARY WILL BRING A PUSH OF DRIER AIR INTO THE AREA EARLY THIS EVENING AS THE UPPER WAVE EXITS. THIS WILL BRING AN END TO ANY CONVECTION. WILL KEEP A MINIMAL CHANCE FOR POPS VERY EARLY THIS EVENING. OTHERWISE DRY WEATHER IS EXPECT TONIGHT. CANNOT RULE OUT SOME PATCHY FOG LATE ACROSS SOUTHERN AREAS WHERE WINDS WILL BE LIGHTEST BUT THERE MAY BE ENOUGH OF A BREEZE TO MITIGATE ANY DEVELOPMENT. FURTHER NORTH...DECREASING DEWPOINTS AND A SLIGHT BREEZE SHOULD FURTHER REDUCE THE CHANCE FOR FOG DEVELOPMENT. MDB && .LONG TERM... TUESDAY THROUGH MONDAY... 306 PM...MAIN FORECAST CONCERN IS PRECIP CHANCES THURSDAY NIGHT THRU FRIDAY NIGHT AND AGAIN SUNDAY NIGHT INTO MONDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION TUESDAY AND TUESDAY NIGHT AND THEN SLOWLY SAG SOUTHEAST OF THE AREA WEDNESDAY NIGHT INTO THURSDAY. THIS WILL PROVIDE DRY WEATHER WITH NORTHEAST WINDS OFF THE LAKE TUESDAY AND THEN A LAKE BREEZE WEDNESDAY...KEEPING AREAS NEAR THE LAKE A FEW DEGREES COOLER BUT WITH MOSTLY SUNNY SKIES...TEMPS INLAND SHOULD REACH AROUND 80 BOTH DAYS. WINDS TURN SOUTHWESTERLY WEDNESDAY NIGHT AS THE LOW LEVELS BEGIN TO WARM SOME OVERNIGHT. NOT SURE HOW LOW TEMPS WILL DROP NOW WEDNESDAY NIGHT INTO THURSDAY MORNING WITH THIS WARMING ALOFT. STILL POSSIBLE FOR SOME MID/UPPER 50S LOW TEMPS AWAY FROM URBAN AREAS AND PERHAPS MOST LIKELY INTO NORTHWEST INDIANA. THURSDAY LOOKING TO BE A BREEZY WARM DAY AS HIGHS REBOUND BACK INTO THE MID 80S. AN UPPER LEVEL WAVE IS EXPECTED TO MOVE ACROSS THE WESTERN LAKES REGION THURSDAY NIGHT INTO FRIDAY WHICH WILL BE THE NEXT CHANCE FOR SHOWERS/THUNDERSTORMS. OVERALL CONFIDENCE IS SOMEWHAT LOW REGARDING COVERAGE/TIMING BUT CHANCE POPS INTO FRIDAY EVENING LOOK REASONABLE. WINDS WILL LIKELY TURN OFF THE LAKE POSSIBLY FRIDAY AFTERNOON BUT ESPECIALLY ON SATURDAY. THE UPPER RIDGE BUILDS BACK INTO THE REGION SUNDAY INTO MONDAY. TEMPS WILL LIKELY RISE BACK INTO THE MID...PERHAPS UPPER 80S DURING THIS TIME PERIOD WITH A STRONGER COLD FRONT MOVING SOUTH INTO THE UPPER MIDWEST/NORTHERN LAKES REGION SUNDAY/SUNDAY NIGHT. STILL TIMING DIFFERENCES WITH HOW FAST THIS FRONT MOVES SOUTH ACROSS THE AREA EARLY NEXT WEEK. OUTSIDE OF ANY LAKE COOLING...APPEARS HIGHS IN THE MID 80...PERHAPS UPPER 80S...IS ON TRACK FROM THURSDAY UNTIL THIS FRONT ARRIVES EARLY NEXT WEEK. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * ISOLATED SHRA NEXT 2-3 HOURS...THOUGH TSRA COVERAGE DECREASING VCNTY ORD/MDW AND BECOMING FOCUSED MAINLY SOUTH-SOUTHWEST OF THE TERMINALS. * NORTHERLY WINDS AT OR BELOW 10 KTS...THOUGH DIRECTION VARIABLE AT TIMES INTO EARLY EVENING WITH SHRA OUTFLOW. * LAKE BREEZE DEVELOPMENT TUESDAY AFTERNOON. MM/RATZER //DISCUSSION...UPDATED 18Z... LINE OF THUNDERSTORMS ALONG A NOW DEFINED BOUNDARY CONTINUES TO SWEEP ACROSS THE CHICAGO TERMINALS EARLY THIS AFTERNOON. MAIN CELLS APPEAR TO MISS ORD AND MDW...WITH VICINITY THUNDER COVERING THIS FEATURE. SECOND BOUNDARY APPEARS TO ENTER THE AIRSPACE AROUND 20Z AS NOTED IN WEAK RADAR RETURNS IN CENTRAL WISCONSIN. THE INITIAL LINE SHOULD LOWER INSTABILITY...LEAVING LESS ENERGY FOR THE SECOND BOUNDARY TO TAP INTO. HAVE LEFT VCSH IN THE TAF WITH NO MENTION OF THUNDER. FORECAST SOUNDINGS STILL SHOW LAPSE RATES IN THE 8-10 C/KM RANGE WITH CONVECTIVE TEMPS OF 80F...SO THUNDER IS NOT COMPLETELY OUT OF THE QUESTION IN THE 20-23Z TIMEFRAME. BEHIND THE BOUNDARY...MAINLY VFR CONDITIONS ARE LIKELY FOR AN EXTENDED PERIOD OF TIME. WHILE OUTLYING AREAS MAY SEE PATCHY AM FOG...THE CHICAGO TERMINALS SHOULD STAY VFR. THE FOLLOWING FEW DAYS WILL ALLOW FOR LAKE BREEZE CHANCES GENERALLY INITIALIZING IN THE 19-22Z TIMEFRAME. MM //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH FOR SHRA/TSRA TRENDS INTO THIS EVENING. * MEDIUM-HIGH IN WIND DIRECTION THIS EVENING. * MEDIUM FOR LAKE BREEZE TUESDAY. MM/RATZER //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT AND WEDNESDAY...VFR. NNE WINDS ABOVE 10 KT. THURSDAY...VFR. SLIGHT CHANCE TSRA THURSDAY NGT. WEST-SOUTHWEST WINDS. FRIDAY...CHANCE TSRA. WEST-SOUTHWEST WINDS. SATURDAY...VFR. EAST WINDS. SUNDAY...VFR. SOUTH-SOUTHWEST WINDS. KMD && .MARINE... 306 PM...LOW PRESSURE OVER THE SOUTHERN LAKES THIS AFTERNOON WILL MOVE TO NEAR LAKE ONTARIO TUESDAY MORNING AS IT SLOWLY DEEPENS. THIS LOW WILL THEN ABSORB ANOTHER LOW OVER NORTHERN QUEBEC ON TUESDAY. THE GRADIENT WILL TIGHTEN ACROSS THE WESTERN LAKES BETWEEN THIS LOW AND HIGH PRESSURE OVER THE PLAINS WHICH WILL BUILD SOUTHEAST TUESDAY INTO WEDNESDAY. NORTHERLY WINDS WILL INCREASE TO 15-25KTS LATER TONIGHT AND CONTINUE INTO TUESDAY EVENING...BEFORE DIMINISHING TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE HIGH APPROACHES. LOW PRESSURE WILL MOVE ACROSS ONTARIO THURSDAY AS THE HIGH REMAINS OVER THE OHIO VALLEY AND THIS WILL TIGHTEN GRADIENT ACROSS LAKE MICHIGAN THURSDAY INTO THURSDAY NIGHT WITH SOUTHWEST WINDS PERHAPS AS HIGH AS 15-25 KT WHICH WILL THEN DIMINISH LATER THURSDAY NIGHT INTO FRIDAY. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...9 AM TUESDAY TO 7 AM WEDNESDAY. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...9 AM TUESDAY TO 4 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
350 PM CDT MON AUG 10 2015 .MESOSCALE DISCUSSION... 349 PM CDT THREE LINES OF SHOWERS WITH EMBEDDED THUNDERSTORMS CONTINUE TO TRACK SOUTHWARD FROM CENTRAL WISCONSIN TO NORTHERN ILLINOIS. THE FIRST LINE...NOW EXTENDING FROM LONG POINT TO DE MOTTE...HAS LOST MUCH OF ITS STRENGTH AS THE OUTFLOW BOUNDARY HAS OUTRUN THE MAIN LINE OF STORMS. THIS OUTFLOW HAS SHOWN GUSTS OF 25KT AT IKK WITH SIMILAR VALUES EXPECTED FOR THE REMAINDER OF ITS LIFE IN THE CWA. SINCE THIS LINE HAS THE MOST UNTAPPED INSTABILITY TO WORK WITH...A FEW GIRTHY YET SUB-SEVERE STORMS ARE POSSIBLE. THE MIDDLE LINE OF STORM EXTENDING FROM BUFFALO TO NORTH CHICAGO IS CURRENTLY SHOWING THE MOST UPWARD GROWTH AND OUTFLOW INTERACTIONS. DOPPLER RADAR SHOWS NUMEROUS OUTFLOW WAVES FROM MULTIPLE PREVIOUS STORMS. THESE INTERACTIONS CAN ACT TO CREATE LOW LEVEL WIND SHEAR AND MAY PROMPT BRIEF FUNNEL CLOUD DEVELOPMENT. ONE CELL IN PARTICULAR FROM CAROL STREAM HEADED SOUTH TOWARD DOWNERS GROVE HAS SHOWN NEARLY 60 DBZ OF REFLECTIVITY ABOVE THE -20C LINE. 1 INCH HAIL IS NOT OUT OF THE QUESTION WITH CELLS SIMILAR TO THIS OVER THE NEXT 2-3 HOURS WHILE DAYTIME HEATING IS STILL ABUNDANT. EXPECT CONTINUED INTERACTIONS TO ALSO FUEL CELL GROWTH. IN THIS REGIME...EVEN VERTICALLY CHALLENGED CELLS MAY SHOW SIGNS OF BRIEF ROTATION...BUT WIDESPREAD TORNADIC ACTIVITY IS NOT ANTICIPATED. THE THIRD/NORTHERLY LINE MARKS A COLD FRONT WHERE DEWPOINT TEMPERATURES DROP ROUGHLY 10 DEGREES. THIS LINE HAS THE MOST SUFFICIENT FORCING MECHANISM...BUT LITTLE IN THE WAY OF INSTABILITY. THE FRONT WILL BE HALFWAY ACROSS THE CWA BY 23Z (MENDOTA TO PLAINFIELD TO GARY)...AT WHICH POINT THE LOSS OF DAYTIME HEATING IS EXPECTED TO CEASE REMAINING THUNDER CHANCES. THIS IS SUPPORTED BY THE EXPERIMENTAL HRRR THAT SUGGESTS ISOLATED LINGERING SHOWERS THROUGH 00Z. MM && .SHORT TERM... 237 PM CDT THROUGH TONIGHT... A SERIES OF SHORTWAVE TROUGHS CONTINUE TO TRACK SOUTHEAST ACROSS THE REGION GENERATING BANDS OF SHOWERS AND THUNDERSTORMS. THE FIRST WAVE IS CROSSING FAR SOUTHERN LAKE MICHIGAN PUSHING A BAND OF SHOWERS AND STORMS SOUTHWARD ALONG THE I-80 CORRIDOR AT THIS TIME WITH ANOTHER CLUSTER OUT OVER LAKE MICHIGAN. WITH THE MOVEMENT OF THE WAVE HAVING AN EASTWARD COMPONENT THE BETTER LARGER SCALE FORCING WILL BE SHIFTING AWAY FROM THE CURRENT BAND OF ACTIVITY ALONG I-80 SO THIS AREA MAY START TO FADE IN COVERAGE OVER THE NEXT COUPLE HOURS. IN ADDITION...OUTFLOW IS NOW OUTRUNNING THE CONVECTION SUPPORTING A DOWNWARD TREND. HOWEVER...WITH AN UNSTABLE AIRMASS IN PLACE THE OUTFLOW MAY GENERATE NEW STORMS SOUTH OF I-80 BUT THE EXITING OF THE UPPER FORCING SUGGESTS MORE ISOLATED COVERAGE TO ANYTHING ADDITIONAL. AREAS OF NORTHWEST INDIANA PROBABLY HAVE THE BEST CHANCE FOR RENEWED DEVELOPMENT FROM THIS FIRST WAVE THROUGH LATE AFTERNOON. ATTENTION TURNS TO A SECOND WAVE TRACKING ACROSS CENTRAL WISCONSIN WHICH IS GENERATING SCATTERED CONVECTION ACROSS MUCH OF SOUTHERN WISCONSIN. THIS ACTIVITY IS MORE DISJOINTED IN COVERAGE BUT WILL LIKELY CONTINUE INTO NORTHERN ILLINOIS INTO LATE AFTERNOON...WITH ADDITIONAL DEVELOPMENT ACROSS NORTHERN ILLINOIS IN THE MEANTIME. STORM ORGANIZATION WILL LIKELY BE A BIGGER CHALLENGE NORTH OF I-80 GIVEN THE PREVIOUS ACTIVITY BUT SOME BRIEF PULSING OF UPDRAFTS MAY PRODUCE SOME SMALL HAIL AND SOME SUB SEVERE WIND GUSTS. A SUBTLE COOL FRONTAL BOUNDARY WILL BRING A PUSH OF DRIER AIR INTO THE AREA EARLY THIS EVENING AS THE UPPER WAVE EXITS. THIS WILL BRING AN END TO ANY CONVECTION. WILL KEEP A MINIMAL CHANCE FOR POPS VERY EARLY THIS EVENING. OTHERWISE DRY WEATHER IS EXPECT TONIGHT. CANNOT RULE OUT SOME PATCHY FOG LATE ACROSS SOUTHERN AREAS WHERE WINDS WILL BE LIGHTEST BUT THERE MAY BE ENOUGH OF A BREEZE TO MITIGATE ANY DEVELOPMENT. FURTHER NORTH...DECREASING DEWPOINTS AND A SLIGHT BREEZE SHOULD FURTHER REDUCE THE CHANCE FOR FOG DEVELOPMENT. MDB && .LONG TERM... TUESDAY THROUGH MONDAY... 306 PM...MAIN FORECAST CONCERN IS PRECIP CHANCES THURSDAY NIGHT THRU FRIDAY NIGHT AND AGAIN SUNDAY NIGHT INTO MONDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION TUESDAY AND TUESDAY NIGHT AND THEN SLOWLY SAG SOUTHEAST OF THE AREA WEDNESDAY NIGHT INTO THURSDAY. THIS WILL PROVIDE DRY WEATHER WITH NORTHEAST WINDS OFF THE LAKE TUESDAY AND THEN A LAKE BREEZE WEDNESDAY...KEEPING AREAS NEAR THE LAKE A FEW DEGREES COOLER BUT WITH MOSTLY SUNNY SKIES...TEMPS INLAND SHOULD REACH AROUND 80 BOTH DAYS. WINDS TURN SOUTHWESTERLY WEDNESDAY NIGHT AS THE LOW LEVELS BEGIN TO WARM SOME OVERNIGHT. NOT SURE HOW LOW TEMPS WILL DROP NOW WEDNESDAY NIGHT INTO THURSDAY MORNING WITH THIS WARMING ALOFT. STILL POSSIBLE FOR SOME MID/UPPER 50S LOW TEMPS AWAY FROM URBAN AREAS AND PERHAPS MOST LIKELY INTO NORTHWEST INDIANA. THURSDAY LOOKING TO BE A BREEZY WARM DAY AS HIGHS REBOUND BACK INTO THE MID 80S. AN UPPER LEVEL WAVE IS EXPECTED TO MOVE ACROSS THE WESTERN LAKES REGION THURSDAY NIGHT INTO FRIDAY WHICH WILL BE THE NEXT CHANCE FOR SHOWERS/THUNDERSTORMS. OVERALL CONFIDENCE IS SOMEWHAT LOW REGARDING COVERAGE/TIMING BUT CHANCE POPS INTO FRIDAY EVENING LOOK REASONABLE. WINDS WILL LIKELY TURN OFF THE LAKE POSSIBLY FRIDAY AFTERNOON BUT ESPECIALLY ON SATURDAY. THE UPPER RIDGE BUILDS BACK INTO THE REGION SUNDAY INTO MONDAY. TEMPS WILL LIKELY RISE BACK INTO THE MID...PERHAPS UPPER 80S DURING THIS TIME PERIOD WITH A STRONGER COLD FRONT MOVING SOUTH INTO THE UPPER MIDWEST/NORTHERN LAKES REGION SUNDAY/SUNDAY NIGHT. STILL TIMING DIFFERENCES WITH HOW FAST THIS FRONT MOVES SOUTH ACROSS THE AREA EARLY NEXT WEEK. OUTSIDE OF ANY LAKE COOLING...APPEARS HIGHS IN THE MID 80...PERHAPS UPPER 80S...IS ON TRACK FROM THURSDAY UNTIL THIS FRONT ARRIVES EARLY NEXT WEEK. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * THUNDER FOR 1 HOUR AND SHRA MOVING THROUGH TERMINALS CURRENTLY. * NORTH TO NORTHEAST WINDS GENERALLY UNDER 9KT TODAY...EXCEPT BRIEF NORTHEAST GUSTS TO 20KT. * LAKE BREEZE DEVELOPMENT TUESDAY AFTERNOON. MM //DISCUSSION...UPDATED 18Z... LINE OF THUNDERSTORMS ALONG A NOW DEFINED BOUNDARY CONTINUES TO SWEEP ACROSS THE CHICAGO TERMINALS EARLY THIS AFTERNOON. MAIN CELLS APPEAR TO MISS ORD AND MDW...WITH VICINITY THUNDER COVERING THIS FEATURE. SECOND BOUNDARY APPEARS TO ENTER THE AIRSPACE AROUND 20Z AS NOTED IN WEAK RADAR RETURNS IN CENTRAL WISCONSIN. THE INITIAL LINE SHOULD LOWER INSTABILITY...LEAVING LESS ENERGY FOR THE SECOND BOUNDARY TO TAP INTO. HAVE LEFT VCSH IN THE TAF WITH NO MENTION OF THUNDER. FORECAST SOUNDINGS STILL SHOW LAPSE RATES IN THE 8-10 C/KM RANGE WITH CONVECTIVE TEMPS OF 80F...SO THUNDER IS NOT COMPLETELY OUT OF THE QUESTION IN THE 20-23Z TIMEFRAME. BEHIND THE BOUNDARY...MAINLY VFR CONDITIONS ARE LIKELY FOR AN EXTENDED PERIOD OF TIME. WHILE OUTLYING AREAS MAY SEE PATCHY AM FOG...THE CHICAGO TERMINALS SHOULD STAY VFR. THE FOLLOWING FEW DAYS WILL ALLOW FOR LAKE BREEZE CHANCES GENERALLY INITIALIZING IN THE 19-22Z TIMEFRAME. MM //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH FOR SHRA AND MEDIUM HIGH FOR THUNDER. * HIGH FOR WINDS TODAY. * MEDIUM FOR LAKE BREEZE TUESDAY. MM //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT AND WEDNESDAY...VFR. NNE WINDS ABOVE 10 KT. THURSDAY...VFR. SLIGHT CHANCE TSRA THURSDAY NGT. WEST-SOUTHWEST WINDS. FRIDAY...CHANCE TSRA. WEST-SOUTHWEST WINDS. SATURDAY...VFR. EAST WINDS. SUNDAY...VFR. SOUTH-SOUTHWEST WINDS. KMD && .MARINE... 306 PM...LOW PRESSURE OVER THE SOUTHERN LAKES THIS AFTERNOON WILL MOVE TO NEAR LAKE ONTARIO TUESDAY MORNING AS IT SLOWLY DEEPENS. THIS LOW WILL THEN ABSORB ANOTHER LOW OVER NORTHERN QUEBEC ON TUESDAY. THE GRADIENT WILL TIGHTEN ACROSS THE WESTERN LAKES BETWEEN THIS LOW AND HIGH PRESSURE OVER THE PLAINS WHICH WILL BUILD SOUTHEAST TUESDAY INTO WEDNESDAY. NORTHERLY WINDS WILL INCREASE TO 15-25KTS LATER TONIGHT AND CONTINUE INTO TUESDAY EVENING...BEFORE DIMINISHING TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE HIGH APPROACHES. LOW PRESSURE WILL MOVE ACROSS ONTARIO THURSDAY AS THE HIGH REMAINS OVER THE OHIO VALLEY AND THIS WILL TIGHTEN GRADIENT ACROSS LAKE MICHIGAN THURSDAY INTO THURSDAY NIGHT WITH SOUTHWEST WINDS PERHAPS AS HIGH AS 15-25 KT WHICH WILL THEN DIMINISH LATER THURSDAY NIGHT INTO FRIDAY. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...9 AM TUESDAY TO 7 AM WEDNESDAY. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...9 AM TUESDAY TO 4 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
255 PM CDT MON AUG 10 2015 .SHORT TERM...(TONIGHT) ISSUED AT 254 PM CDT MON AUG 10 2015 ISOLATED SHOWERS AND THUNDERSTORMS WILL OCCUR UNTIL SUNSET OVER CENTRAL AND SOUTHEAST IL. A FRONTAL BOUNDARY ALONG A PARIS TO CHARLESTON TO EFFINGHAM TO VANDALIA LINE WILL PUSH THROUGH SE IL LATE THIS AFTERNOON GIVING ISOLATED CONVECTION THERE. MEANWHILE AN UPPER LEVEL SHORT WAVE OVER SOUTHERN LAKE MI INTO NORTHERN IL WILL PUSH INTO CENTRAL IL BY 00Z WITH THE BRUNT OF ITS LIFT PASSING NE OF CENTRAL IL OVER NORTHERN HALF OF INDIANA INTO SOUTHERN LOWER MI. SCATTERED SHOWERS AND THUNDERSTORMS OVER NORTHERN IL JUST NORTH OF CWA WILL PUSH SE INTO THE IL RIVER VALLEY LATE THIS AFTERNOON AND TOWARD I-72 EARLY THIS EVENING. CAPES PEAK FROM 1500-3000 J/KG THIS AFTERNOON WITH BULK SHEAR OF 20-40 KTS. THIS COULD SUPPORT A FEW STRONG THUNDERSTORMS FROM I-74 NE AND FROM I-70 SE UNTIL 00Z/7 PM. WEAK HIGH PRESSURE BUILD ACROSS THE MIDWEST INTO TONIGHT AND NW WINDS TO BRING IN SOMEWHAT COOLER AND LESS HUMID AIR. LOWS OVERNIGHT IN MID 60S WITH SOME UPPER 60S SOUTH OF I-70. PATCHY SHALLOW GROUND FOG POSSIBLE LATE TONIGHT SE OF THE IL RIVER AND MORE WIDESPREAD IN AREAS EAST AND SOUTH OF CENTRAL IL. && .LONG TERM...(TUESDAY THROUGH MONDAY) ISSUED AT 254 PM CDT MON AUG 10 2015 SURFACE HIGH PRESSURE WILL BUILD INTO THE MIDWEST THROUGH MIDWEEK WHILE NORTHWEST FLOW AFFECTS THE AREA BETWEEN UPPER LEVEL RIDGING OVER THE ROCKIES/WESTERN PLAINS AND TROUGHING OVER THE EAST COAST. RELATIVELY MILD TEMPERATURES AND LESS HUMIDITY WILL BE ASSOCIATED WITH THIS PATTERN AND HIGHS ARE EXPECTED IN THE LOW TO MID 80S TUESDAY THROUGH THURSDAY...WITH DEWPOINTS IN THE 60S. LOWS FROM AROUND 60 TO 65 EXPECTED EACH NIGHT. A WEAKENING COLD FRONT CONTINUES IN MODEL FORECASTS FOR FRIDAY. THE BULK OF MODEL GUIDANCE DROPS THE FRONTAL BOUNDARY FROM THE GREAT LAKES REGION SOUTHWARD...PRIMARILY THROUGH AREAS EAST OF ILLINOIS. THE BOUNDARY COULD BE A FOCUS FOR SHOWERS AND THUNDERSTORMS IN NORTHERN AND EAST CENTRAL IL FRIDAY AND FRIDAY NIGHT. VERY LITTLE COLD AIR IS EXPECTED TO PUSH INTO CENTRAL IL...AND TEMPERATURES SHOULD CONTINUE A SLOW CLIMB INTO THE MID AND UPPER 80S FRIDAY THROUGH MONDAY. ANOTHER COLD FRONT COULD POTENTIALLY AFFECT THE AREA EARLY NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1258 PM CDT MON AUG 10 2015 A FRONTAL BOUNDARY SOUTH OF I-72 WILL PUSH INTO SOUTHEAST IL DURING THIS AFTERNOON WITH NW WIND 5-10 KTS BEHIND THIS BOUNDARY OVER CENTRAL IL AIRPORTS. ISOLATED CONVECTION STARTED TO DEVELOPING ALONG THIS BOUNDARY WHICH HAS MISSED THE CENTRAL IL TAF SITES. AN UPPER LEVEL TROF OVER SE WI AND NW IL WILL MOVE INTO THE IL RIVER VALLEY LATE THIS AFTERNOON. SCATTERED CONVECTION OVER NORTHERN IL NORTH OF I-80 WILL SPREAD SE AT 30 MPH TOWARD PIA BY 20Z AND BMI AND POSSIBLY CMI BETWEEN 21-22Z AS IT BECOMES MORE ISOLATED. SO CARRIED VCTS/VCSH TO ADDRESS THIS CHANCE WITH MVFR CEILINGS POSSIBLE AT TIMES THIS AFTERNOON. ISOLATED CONVECTION SHOULD END BY SUNSET LEAVING MOSTLY CLEAR SKIES AND LIGHT NW WINDS TONIGHT. HAVE 3-5 MILES FOG FROM 09Z-14Z WHILE MORE WIDESPREAD AND DENSER FOG TO OCCUR NE OF CMI OVER INDIANA AND NE IL AND SW OF SPI OVER SW IL INTO MO AND WESTERN KY PER HRRR MODEL VSBY FORECAST THRU 07Z. WINDS TO BE NORTH 5-9 KTS AFTER 14Z TUE MORNING. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...07 LONG TERM...ONTON AVIATION...07
AREA FORECAST DISCUSSION
NWS LINCOLN IL
101 PM CDT MON AUG 10 2015 .UPDATE... ISSUED AT 1045 AM CDT MON AUG 10 2015 UPDATED THE FORECAST DURING MID MORNING WITH DENSE FOG ADVISORY ENDING AT 9 AM ACROSS NORTHERN HALF OF CWA. WILL ISSUE ANOTHER UPDATE LATE THIS MORNING TO REMOVE MENTION OF PATCHY FOG THIS MORNING. OTHERWISE REST OF FORECAST LOOKS ON TRACK THIS AFTERNOON. HAVE 20-30% CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AS WARM AND HUMID CONDITIONS PREVAIL WITH DEWPOINTS OF 70-75F AND SEASONABLE HIGHS IN THE LOW TO MID 80S. A WEAK FRONTAL BOUNDARY JUST SE OF A RANTOUL TO DECATUR TO TAYLORVILLE LINE WILL PUSH SE ACROSS SOUTHEAST IL DURING THIS AFTERNOON GIVING ISOLATED SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF IT WHERE UNSTABLE AIRMASS WITH CAPES OF 1500-2500 J/KG. MEANWHILE A SHORT WAVE TROF OVER SE WI INTO IA WILL SHIFT SE INTO THE IL RIVER VALLEY LATER THIS AFTEROON GIVING A CHANCE OF SHOWERS/THUNDESTORMS THERE AS WELL. SPC KEEPS MARGINAL RISK OF SEVERE STORMS SE OF CWA THIS AFTERNOON. && .SHORT TERM...(TODAY) ISSUED AT 305 AM CDT MON AUG 10 2015 07Z/2AM SURFACE ANALYSIS SHOWS A 1010MB LOW OVER CENTRAL ILLINOIS...WITH A FRONTAL BOUNDARY EXTENDING SOUTHWESTWARD INTO THE OZARKS. A LARGE CLUSTER OF THUNDERSTORMS THAT DEVELOPED ALONG AN OLD OUTFLOW BOUNDARY IS ONGOING WELL SOUTH OF THE FRONT ACROSS SOUTHERN MISSOURI INTO FAR SOUTHERN ILLINOIS...HOWEVER THESE STORMS ARE DROPPING SOUTHWARD AWAY FROM THE KILX CWA. MEANWHILE...ANOTHER WEAK FRONT IS ANALYZED ACROSS CENTRAL IOWA WHERE A SECOND CLUSTER OF SHOWERS AND THUNDERSTORMS IS LOCATED. HRRR SUGGESTS THESE STORMS WILL WEAKEN AS THEY TRACK SLOWLY EASTWARD AND WILL NEVER REACH CENTRAL ILLINOIS. RAPIDLY WARMING CLOUD TOPS ON LATEST IR SATELLITE IMAGERY SUPPORT THIS THEORY...SO HAVE MAINTAINED A DRY FORECAST ACROSS THE ENTIRE AREA EARLY THIS MORNING. MAIN CONCERN EARLY ON WILL BE AREAS OF FOG THANKS TO AMPLE LOW-LEVEL MOISTURE...LIGHT WINDS...AND BREAKS IN THE OVERCAST. VSBYS HAVE OCCASIONALLY DROPPED TO AROUND 1/4 MILE ACROSS THE FAR NORTHERN CWA OVER THE PAST HOUR...SO WILL NEED TO MONITOR TRENDS CLOSELY FOR POTENTIAL DENSE FOG ADVISORY. AT THIS POINT...FOG HAS NOT BEEN CONSISTENTLY DENSE OR WIDESPREAD...SO WILL HOLD OFF ON AN ADVISORY. AS THE IOWA FRONT SAGS SOUTHEASTWARD...A FEW SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON DURING PEAK HEATING. WITH SURFACE DEWPOINTS REMAINING IN THE LOWER TO MIDDLE 70S...SBCAPE VALUES WILL REACH THE 1500 TO 2500J/KG RANGE. WEAK CONVERGENCE ALONG THE FRONT WILL BE ENOUGH TO TRIGGER WIDELY SCATTERED CONVECTION...PARTICULARLY ACROSS THE CENTRAL/NORTHERN CWA IN CLOSER PROXIMITY TO THE BOUNDARY. WILL CARRY 30 POPS ACROSS THIS AREA...TAPERING DOWN TO 20S ALONG/SOUTH OF I-70. .LONG TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 305 AM CDT MON AUG 10 2015 ANY LINGERING SHOWERS/THUNDERSTORMS WILL QUICKLY DISSIPATE AFTER SUNSET AS DAYTIME INSTABILITY WANES. HAVE THEREFORE INCLUDED A 20 POP ACROSS THE BOARD THROUGH MID-EVENING...THEN HAVE GONE DRY OVERNIGHT. COOLER/LESS HUMID AIR WILL GRADUALLY TRICKLE SOUTHWARD INTO THE AREA TONIGHT THROUGH THURSDAY AS HIGH PRESSURE BUILDS INTO THE REGION. AFTERNOON HIGHS WILL BE IN THE LOWER TO MIDDLE 80S WHILE OVERNIGHT LOWS DROP INTO THE UPPER 50S AND LOWER 60S EACH DAY. AFTER THAT...MODELS CONTINUE TO ADVERTISE A WEAKENING COLD FRONT DROPPING INTO THE REGION LATE IN THE WEEK. BOTH THE GFS AND ECMWF ARE SLIGHTLY SLOWER WITH THE BOUNDARY THAN IN PRIOR RUNS...WITH THE FRONT REMAINING ACROSS NORTHERN ILLINOIS UNTIL FRIDAY NIGHT/SATURDAY. WITH PRONOUNCED UPPER RIDGE INITIALLY POSITIONED OVER THE PLAINS/SOUTHERN CANADA BUILDING EASTWARD...RISING UPPER HEIGHTS WILL CREATE AN UNFAVORABLE ENVIRONMENT FOR THE ALREADY WEAK FRONT. AS SUCH...BOTH MODELS SUGGEST IT WILL COMPLETELY DISSIPATE BEFORE PASSING THROUGH CENTRAL ILLINOIS. HAVE MAINTAINED JUST A SLIGHT CHANCE POP ALONG/NORTH OF I-74 ON FRIDAY IN CASE BOUNDARY CAN GET CLOSE ENOUGH TO TRIGGER ISOLATED STORMS...THEN HAVE RETURNED TO A DRY FORECAST FRIDAY NIGHT THROUGH SUNDAY AS FRONT WASHES OUT. TEMPERATURES OVER THE WEEKEND WILL CLIMB BACK INTO THE UPPER 80S TO AROUND 90 BEFORE THE NEXT FRONT POTENTIALLY COMES INTO THE PICTURE BY NEXT MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1258 PM CDT MON AUG 10 2015 A FRONTAL BOUNDARY SOUTH OF I-72 WILL PUSH INTO SOUTHEAST IL DURING THIS AFTERNOON WITH NW WIND 5-10 KTS BEHIND THIS BOUNDARY OVER CENTRAL IL AIRPORTS. ISOLATED CONVECTION STARTED TO DEVELOPING ALONG THIS BOUNDARY WHICH HAS MISSED THE CENTRAL IL TAF SITES. AN UPPER LEVEL TROF OVER SE WI AND NW IL WILL MOVE INTO THE IL RIVER VALLEY LATE THIS AFTERNOON. SCATTERED CONVECTION OVER NORTHERN IL NORTH OF I-80 WILL SPREAD SE AT 30 MPH TOWARD PIA BY 20Z AND BMI AND POSSIBLY CMI BETWEEN 21-22Z AS IT BECOMES MORE ISOLATED. SO CARRIED VCTS/VCSH TO ADDRESS THIS CHANCE WITH MVFR CEILINGS POSSIBLE AT TIMES THIS AFTERNOON. ISOLATED CONVECTION SHOULD END BY SUNSET LEAVING MOSTLY CLEAR SKIES AND LIGHT NW WINDS TONIGHT. HAVE 3-5 MILES FOG FROM 09Z-14Z WHILE MORE WIDESPREAD AND DENSER FOG TO OCCUR NE OF CMI OVER INDIANA AND NE IL AND SW OF SPI OVER SW IL INTO MO AND WESTERN KY PER HRRR MODEL VSBY FORECAST THRU 07Z. WINDS TO BE NORTH 5-9 KTS AFTER 14Z TUE MORNING. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...07 SHORT TERM...BARNES LONG TERM...BARNES AVIATION...07
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
338 PM EDT MON AUG 10 2015 .SYNOPSIS... ISSUED AT 335 PM EDT MON AUG 10 2015 A COUPLE OF UPPER LEVEL DISTURBANCES WILL CONTINUE TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS THIS EVENING. DRIER AIR WILL FILTER INTO THE AREA LATER THIS EVENING INTO THE OVERNIGHT BEHIND THIS SYSTEM. DRY WEATHER IS THEN EXPECTED THROUGH MID WEEK. LOW TEMPERATURES TONIGHT WILL DROP INTO THE LOWER TO MID 60S. HIGH TEMPERATURES ON TUESDAY WILL REACH INTO THE MID TO UPPER 70S. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 335 PM EDT MON AUG 10 2015 LEAD SHORT WAVE WHICH TRACKED ACROSS THE AREA EARLIER TODAY ALLOWED FOR INITIAL WEAK LAKE ENHANCED SURFACE TROUGH TO SERVE AS FOCUSING MECHANISM FOR SCATTERED SHOWERS/ISOLATED STORMS. OVER PAST HOUR...STARTING TO SEE UPSWING IN CONVECTIVE COVERAGE ALONG THIS BOUNDARY AS A STRONGER UPSTREAM VORT MAX ACROSS NORTHERN ILLINOIS CONTINUES TO APPROACH THE AREA. A SECONDARY AREA OF SCATTERED/NUMEROUS SHOWERS/STORMS HAS DEVELOPED ACROSS FAR SOUTHERN/AND MAINLY SOUTH OF FORECAST AREA ACROSS CENTRAL INDIANA. THIS AREA APPEARS BE TIED MORE CLOSELY TO ENHANCED LOW LEVEL THETAE ADVECTION...WHICH ALSO IS COLOCATED WITH MORE PRONOUNCED INSTABILITY AXIS WITH LATEST RUC ANALYSIS DEPICTING 100 HPA MLCAPES ON THE ORDER OF 1000-1500 J/KG. MODEST DEEP LAYER SHEAR AND AND WEAK TO MODERATE INSTABILITY WILL CONTINUE TO POSE SOME THREAT OF ISOLD STRONG STORMS WITH GUSTY WINDS AS THE MAIN THREAT. WHILE BRIEF VERY HEAVY RAINFALL IS POSSIBLE...PROPAGATION VECTORS ARE SLIGHTLY MORE PROGRESSIVE THIS AFTERNOON IN COMPARISON TO LAST EVENING AND CURRENT THINKING IS THAT WHILE LOCALIZED PONDING OF WATER/MINOR FLOODING IS POSSIBLE WITH THE STRONGER STORMS...FLASH FLOODING CONCERNS SHOULD BE MINIMAL. PRIMARY INSTABILITY AXIS SHOULD BEGIN TO ADVECT ACROSS FAR EASTERN PORTIONS OF THE FORECAST AREA LATE THIS AFTERNOON...BUT WEAK INSTABILITY WILL REMAIN ACROSS ENTIRE FORECAST AREA AS AFOREMENTIONED NORTHERN ILLINOIS VORT MAX ALLOWS FOR EROSION OF RELATIVELY 800-700 HPA LAYER NOTED PER EARLIER AMDAR REGIONAL SOUNDINGS. THIS SHOULD ALLOW FOR ENOUGH LINGERING INSTABILITY WITH STRONGER ILLINOIS VORT MAX TO KEEP SOME CHANCE OF ISOLD-SCT CONVECTION ACROSS THE AREA EARLY THIS EVENING. QUIET CONDITIONS EXPECTED LATER THIS EVENING INTO THE OVERNIGHT AS SECONDARY SFC TROUGH USHERS IN COOLER AND DRIER LOW LEVEL AIR. QUIET WEATHER EXPECTED FOR TUESDAY WITH PERSISTENT MID LEVEL SUBSIDENCE...ALTHOUGH THE NEXT IN SERIES OF UPPER LEVEL SHORT WAVES IS EXPECTED TO DIG ACROSS THE GREAT LAKES EARLY TUESDAY...WHICH COULD PROMOTE AN ISOLATED SHOWER ACROSS SOUTHEAST LOWER MICHIGAN. GIVEN VERY MARGINAL MOISTURE PROFILES...WILL OMIT FROM FORECAST WITH JUST SLIGHTLY MORE CONCENTRATED DIURNAL CU ACROSS THE FAR NORTHEAST. DESPITE LOW LEVEL CAA...GOOD DEAL OF INSOLATION MOST AREAS SHOULD ALLOW FOR HIGHS IN THE MID TO UPPER 70S. && .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 335 PM EDT MON AUG 10 2015 HIGH PRESSURE MOVING OUT OF CANADA WILL BRING COOL...DRY WEATHER FOR THE FIRST PORTION OF THE LONG TERM PERIOD. AS THE LONGWAVE PATTERN BECOMES MORE ZONAL INTO THE WEEKEND... TEMPERATURES WILL WARM AND A FEW FRONTAL BOUNDARIES WILL DROP SOUTHWARD INTO THE GREAT LAKES REGION WITH SHOWERS AND THUNDERSTORMS POSSIBLE. THE FIRST OF THESE FRONTS WILL DROP THROUGH ON FRIDAY. A FEW STORMS ARE POSSIBLE ALONG THIS FRONT...BUT LIMITED INSTABILITY SHOULD LIMIT WIDESPREAD DEVELOPMENT. THIS FIRST FRONT WILL SETTLE SOUTH OF THE AREA OVER THE WEEKEND WHICH SHOULD KEEP OUR AREA DRY. BETTER SHOWERS AND STORM CHANCES RETURN BY THE EARLY PART OF NEXT WEEK AS MODEL CONSENSUS STALLS A FRONTAL BOUNDARY ACROSS THE SOUTHERN GREAT LAKES. DEWPOINTS IN THE UPPER 60S TO LOW 70S COUPLED WITH DAYTIME HEATING SHOULD PROVIDE WEAK TO MODERATE INSTABILITY EACH DAY...DEPENDING ON THE DEGREE OF HEATING. AT THIS TIME...MID LEVEL LAPSE RATES AND DEEP LAYER SHEAR LOOK LACKLUSTER WHICH SHOULD PRECLUDE ANY ORGANIZED SEVERE WEATHER THREAT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 138 PM EDT MON AUG 10 2015 LAKE ENHANCED SURFACE TROUGH AXIS HAS BEEN FOCAL POINT FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS NORTH CENTRAL INDIANA. THE IMMEDIATE NEAR TERM FOCUS IN THE NEXT 2 HOURS FOR THIS ACTIVITY SHOULD REMAIN SOUTHEAST OF KSBN...AND AFFECT MAINLY KFWA BETWEEN 19Z-22Z. THIS SURFACE TROUGH DOES MARK A PARTICULARLY PRONOUNCED GRADIENT IN TERMS OF MOISTURE...AND ADDITIONAL SHOWERS/STORMS HAVE DEVELOPED ACROSS NORTHEAST ILLINOIS IN CLOSER PROXIMITY TO STRONGER UPPER VORT MAX. THUS...STILL EXPECTING SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM TO AFFECT KSBN IN THE 20Z-22Z TIMEFRAME. WITH INSTABILITY SOMEWHAT ON THE MARGINAL SIDE AND EXPECTED TO BE MORE PRONOUNCED AT KFWA...WILL LIMIT THUNDER MENTION TO VCTS AT KFWA. SHOWERS/STORMS SHOULD DIMINISH AFTER 23Z WITH DRIER AIR ADVECTING INTO NORTHERN INDIANA AND QUIET AVIATION WEATHER CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. NORTHWEST WINDS SHOULD INCREASE IN GUSTINESS INTO THE 15 TO 20 KNOT RANGE FOR TUESDAY AFTERNOON. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...BENTLEY AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
325 PM CDT MON AUG 10 2015 .SYNOPSIS... ISSUED AT 321 PM CDT MON AUG 10 2015 Light northeasterly surface winds prevailed across western and central kansas this afternoon. Regional WSR88D as still showing 30 to 40 dbz reflectivity returns across the TX panhandles into northeast oklahoma associated with the low to mid level baroclinic zone that since has shifted south. Meanwhile a few surface based storms have developed in south central and southeast colorado. widespread 1.3 to 1.5 precipitable water values covered the forecast area, with the greatest amounts in the south. && .SHORT TERM...(THIS EVENING THROUGH Tuesday) ISSUED AT 321 PM CDT MON AUG 10 2015 The latest arw and HRRR models were the most aggressive models with respect to developing convection this afternoon. The 4 km nam and the nmm were not as aggressive. However the nmm and 4 km HRRR were also more aggressive with thunderstorms. The severe threat will be minimal today and tonight with any storms that develop as continued amplification the the upper ridge weakened the shear profiles. However very heavy rainfall from efficient warm rain processes will still be likely for the next day or so, but steering flow will be weak or non existent. based on the HRRR, thunderstorm coverage could become scattered by late in the afternoon. additionally. thunderstorms development across southeast colorado could spread into far southwest kansas later this evening aided by weak vorticity advection embedded in the northwest flow in the models. .LONG TERM...(Tuesday NIGHT THROUGH Monday) ISSUED AT 321 PM CDT MON AUG 10 2015 Beyond the short term, increasingly less humid conditions will develop across central and much of western kansas as surface high pressure from the northern plains begins to have greater influence. The general low level moisture transport signal will remain firmly anchored across the the western counties where the main if any thunderstorms chances will be located, and the low level jet may be the best mechanism for get a few thunderstorms going. Generally high temperatures are forecast around 5 degrees below climatology through the extended. Lowered dew points should translate into overnight lows of a few degrees lower as well on average. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Tuesday AFTERNOON) ISSUED AT 1245 PM CDT MON AUG 10 2015 Light northeasterly upslope surface winds will continue through the day, as a surface high pressure center over the northern plains shifts to the southeast with time. The ARW and HRRR convective allowing models indicate potential for convective redevelopment , but opposed to the less aggressive runs of the NMM and 4km NAM. Additionally with surface convergence and upslope flow, and an impulse aloft moving out of new mexico, higher probability for storms exists over the far southeast kansas counties later this evening. in either case, there is not enough confidence at this time to include either tempo groups of prevailing convective conditions at gck, much less ddc or hys. && .PRELIMINARY POINT TEMPS/POPS... DDC 66 86 66 89 / 30 30 30 30 GCK 66 85 65 89 / 30 40 40 20 EHA 66 82 66 90 / 60 50 30 20 LBL 68 85 67 89 / 50 40 30 20 HYS 64 86 66 88 / 10 20 30 20 P28 70 86 68 88 / 10 10 30 30 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Russell SHORT TERM...Russell LONG TERM...Russell AVIATION...Russell
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1246 PM CDT MON AUG 10 2015 ...UPDATED AVIATION SECTION... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 259 AM CDT MON AUG 10 2015 A shortwave trough progressing across the northern plains has pushed a cold front through western Kansas early this morning. A few elevated showers and thunderstorms had developed and these are expected to dissipate later this morning. A few thunderstorms may redevelop this afternoon with daytime heating given the very moist airmass north of the front, deep subtropical moisture at mid levels and resultant weak capping. An organized cluster of thunderstorms will probably develop just south and southwest of Kansas along the frontal boundary this evening and tonight. However, some elevated shower and thunderstorm activity is still expected across far southwest Kansas tonight. Highs today will be in the upper 80s to lower 90s. .LONG TERM...(Tuesday THROUGH Sunday) ISSUED AT 259 AM CDT MON AUG 10 2015 A cooler, post frontal regime can be expected this week with highs mainly in the 80s through Thursday. However the airmass north of the front will still be moist. Nocturnal showers and thunderstorms are possible Tuesday night along and west of a line from Hays to Dodge City given mid level warm advection. This precipitation will probably be a little father east by Wednesday night, possibly all the way into central Kansas. However, it does not appear as though these will be organized heavy rains events. Drying and a slight warming trend can be expected by the weekend as the mid to upper level flow becomes more meridional as opposed to a more favorable northwesterly direction, with highs warming into the lower 90s. The next cold front may arrive by late Saturday night or Sunday with small chances for thunderstorms. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Tuesday AFTERNOON) ISSUED AT 1245 PM CDT MON AUG 10 2015 light northeasterly upslope surface winds will continue through the day, as a surface high pressure center over the northern plains shifts to the southeast with time. the arw and HRRR convective allowing models indicate potential for convective redevelopment , but opposed to the less aggressive runs of the nmm and 4 km NAM. additionally with surface convergence and upslope flow, and an impulse aloft moving out of new mexico, higher probability for storms exists over the far southeast kansas counties. in either case, there is not enough confidence at this time to include either tempo groups of prevailing convective conditions at gck, much less ddc or hys. && .PRELIMINARY POINT TEMPS/POPS... DDC 92 66 84 66 / 30 20 30 30 GCK 90 66 82 65 / 30 30 40 30 EHA 89 66 81 66 / 40 70 50 30 LBL 91 68 84 67 / 30 60 40 30 HYS 89 64 85 66 / 10 10 20 30 P28 92 70 87 68 / 60 10 20 30 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Finch LONG TERM...Finch AVIATION...Russell
AREA FORECAST DISCUSSION
NWS JACKSON KY
653 PM EDT MON AUG 10 2015 .UPDATE... ISSUED AT 653 PM EDT MON AUG 10 2015 SHOWERS/THUNDERSTORMS ASSOCIATED WITH A MID/UPPER LEVEL WAVE HAVE EXITED TO THE EAST EARLY THIS EVENING. ADDITIONAL SHOWERS/THUNDERSTORMS WERE OCCURRING ALONG A COLD FRONT NORTH OF THE OHIO RIVER. THIS FRONT AND THE POTENTIAL FOR PRECIP WILL MOVE SOUTHEAST THROUGH THE AREA DURING THE NIGHT. HAVE MODIFIED THE PRECIP GRIDS TO REFLECT A LOW POP EARLY THIS EVENING...WITH A LITTLE BIT BETTER CHANCE TO FOLLOW DURING THE NIGHT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 350 PM EDT MON AUG 10 2015 18Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING THROUGH THE OHIO VALLEY WITH A COLD FRONT NOW ENTERING WESTERN KENTUCKY. AHEAD OF THIS BOUNDARY...PLENTY OF MOISTURE AND SOME BREAKS IN THE CLOUDS HAVE ALLOWED A FEW CLUSTERS OF SHOWERS AND STORMS TO DEVELOP THROUGH EAST KENTUCKY. TEMPERATURES ACROSS THE AREA VARY GREATLY BASED ON THE PCPN WITH WESTERN PARTS OF THE CUMBERLAND VALLEY DOWN NEAR 70 WHILE LOW TO MID 80S ARE NOTED ACROSS THE NORTH AND EAST. WINDS ARE GENERALLY FROM THE SOUTHWEST TO WEST AT 5 TO 10 KTS WITH OCCASIONAL GUSTS TO 15 KTS. THE MODELS ARE IN GOOD AGREEMENT AT MID LEVELS THROUGH THE SHORT TERM PORTION OF THE FORECAST WITH AN AMPLIFYING TROUGH DIGGING THROUGH THE GREAT LAKES AND OHIO VALLEY. THIS WILL PUSH THE SOUTHERN PLAINS RIDGE BACK TO THE SOUTHWEST WHILE A SLEW OF MINOR WAVES ROTATE THROUGH THE BASE OF THE TROUGH AND BRUSH BY/MOVE THROUGH EAST KENTUCKY INTO WEDNESDAY MORNING. THE NAM REMAINS A BIT STRONGER WITH THE TROUGH THAN THE CONSENSUS OF THE OTHER MODELS. OTHERWISE...TIMING AND PLACEMENT ARE QUITE SIMILAR AMONGST THE MODELS. ACCORDINGLY...HAVE FOLLOWED THE HRRR M0ST CLOSELY THROUGH THE FIRST PART OF THE SHORT TERM WITH A GENERAL BLEND FAVORED AFTER THAT. SENSIBLE WEATHER WILL FEATURE AN ACTIVE LATE AFTERNOON AND EARLY EVENING PERIOD AS CONVECTION MOVES THROUGH EASTERN KENTUCKY DRIVEN BY INSTABILITY AND DIFFERENTIAL HEATING AS WELL AS OUTFLOW FROM EARLIER STORMS. THE HIGH MOISTURE CONTENT IN THE AIR WILL MAKE HEAVY RAINS A THREAT. IN ADDITION...A FEW OF THE STRONGER STORMS COULD CONTAIN GUSTY WINDS WITH A SMALL POTENTIAL TO DO DAMAGE. WILL CONTINUE TO MENTION THIS CONCERN IN THE FORTHCOMING UPDATE TO THE HWO. THE INSTABILITY WILL WANE AFTER SUNSET...BUT THE APPROACHING SFC FRONT WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE THROUGH THE EVENING AND INTO THE EARLY OVERNIGHT PERIOD. DO EXPECT THE THUNDER TO BE MOSTLY GONE BY MIDNIGHT...THOUGH...SO HAVE DROPPED ITS MENTION IN THE WX GRIDS AFTER THAT TIME. PATCHY FOG WILL BE POSSIBLE AS WELL...POST FRONTAL...LATER TONIGHT...BUT PLENTY OF CLOUDS AROUND SHOULD KEEP THE VISIBILITIES FROM GETTING TOO LOW. A FEW SHOWERS MAY LINGER THROUGH FAR EASTERN KENTUCKY INTO THE DAY TUESDAY AS HIGH PRESSURE ONLY SLOWLY PUSHES INTO THE AREA. THIS HIGH WILL BRING IN DRIER AIR AND...EVENTUALLY... CLEARING SKIES FROM WEST TO EAST LATER TUESDAY. A BETTER CHANCE FOR FOG IN THE VALLEYS...PERHAPS LOCALLY DENSE...CAN THEN BE ANTICIPATED FOR LATER TUESDAY NIGHT INTO WEDNESDAY MORNING. STARTED WITH THE SHORTBLEND GUIDANCE THROUGH THE FIRST PART OF THE FORECAST FOR THE T/TD/WIND GRIDS FOLLOWED BY THE SUPERBLEND FOR THE REMAINDER OF THE TIME. DID MAKE SOME VERY MINOR CHANGES TO LOWS TONIGHT AND TUESDAY NIGHT BASED ON THE TERRAIN. AS FOR POPS...ENDED UP MOST SIMILAR TO A BLEND OF THE WETTER MAV AND DRIER MET NUMBERS TONIGHT AND TUESDAY WITH SINGLE DIGIT POPS FOR TUESDAY NIGHT IN LINE WITH GUIDANCE. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 251 PM EDT MON AUG 10 2015 DRY AND PLEASANT WEATHER IS ON TAP FOR THE EXTENDED PORTION OF THE FORECAST. A LARGE RIDGE OF HIGH PRESSURE IS FORECAST TO BECOME ESTABLISHED OVER THE EASTERN THIRD OF THE CONUS FROM EARLY WEDNESDAY ONWARD. THE RIDGE WILL USHER IN A MUCH COOLER AND DRIER AIR MASS THAN ANY WE HAVE SEEN IN THIS PART OF THE COUNTY IN RECENT WEEKS. BOTH DAY AND NIGHT TIME TEMPERATURES WILL BE RUNNING WELL BELOW AVERAGE THE FIRST COUPLE OF DAYS AND NIGHTS OF THE PERIOD. HIGHS ON TUESDAY AND WEDNESDAY ARE EXPECTED TO TOP OUT IN THE UPPER 70S FOR MOST LOCATIONS...WITH OVERNIGHT LOWS WEDNESDAY AND THURSDAY NIGHT DIPPING INTO THE UPPER 50S FOR EVERYWHERE...EXCEPT RIGHT ALONG THE TENNESSEE BORDER...WHERE A FEW READINGS AT OR JUST ABOVE 60 MIGHT BE REALIZED. NO PRECIPITATION IS IN THE FORECAST AT THIS POINT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 215 PM EDT MON AUG 10 2015 VFR CONDITIONS PREVAIL AT MOST SITES EARLY THIS AFTERNOON AS THE CONVECTION HASN/T BEEN TOO WIDESPREAD AS OF YET. HOWEVER...A HEALTHY CLUSTER OF SHOWERS AND STORMS ARE MOVING THROUGH THE CUMBERLAND VALLEY. LOWER CIG AND VIS CAN BE EXPECTED FOR THOSE LOCATIONS AS WELL AS OTHERS ACROSS THE FORECAST AREA WHEN THE COVERAGE BECOMES MORE EXTENSIVE. FOR THIS...HAVE INCLUDED A TEMPO TO IFR CONDITIONS WITH ANY STORMS. THE CONVECTION SHOULD BECOME MORE SCATTERED BY LATE AFTERNOON AND THROUGH THE EVENING WITH A LOSS OF THUNDER LIKELY FOLLOWING SUNSET. A FEW SHOWERS WILL CONTINUE WELL INTO THE NIGHT...THOUGH ALONG WITH LOWERING CIGS AND SOME MVFR FOG AT ALL SITES. CONDITIONS WILL IMPROVE BACK TO VFR BY MID MORNING ON TUESDAY. OUTSIDE OF ANY STORMS...WINDS WILL BE GENERALLY LIGHT THROUGH THE PERIOD FROM THE WEST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
350 PM EDT MON AUG 10 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 350 PM EDT MON AUG 10 2015 18Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING THROUGH THE OHIO VALLEY WITH A COLD FRONT NOW ENTERING WESTERN KENTUCKY. AHEAD OF THIS BOUNDARY...PLENTY OF MOISTURE AND SOME BREAKS IN THE CLOUDS HAVE ALLOWED A FEW CLUSTERS OF SHOWERS AND STORMS TO DEVELOP THROUGH EAST KENTUCKY. TEMPERATURES ACROSS THE AREA VARY GREATLY BASED ON THE PCPN WITH WESTERN PARTS OF THE CUMBERLAND VALLEY DOWN NEAR 70 WHILE LOW TO MID 80S ARE NOTED ACROSS THE NORTH AND EAST. WINDS ARE GENERALLY FROM THE SOUTHWEST TO WEST AT 5 TO 10 KTS WITH OCCASIONAL GUSTS TO 15 KTS. THE MODELS ARE IN GOOD AGREEMENT AT MID LEVELS THROUGH THE SHORT TERM PORTION OF THE FORECAST WITH AN AMPLIFYING TROUGH DIGGING THROUGH THE GREAT LAKES AND OHIO VALLEY. THIS WILL PUSH THE SOUTHERN PLAINS RIDGE BACK TO THE SOUTHWEST WHILE A SLEW OF MINOR WAVES ROTATE THROUGH THE BASE OF THE TROUGH AND BRUSH BY/MOVE THROUGH EAST KENTUCKY INTO WEDNESDAY MORNING. THE NAM REMAINS A BIT STRONGER WITH THE TROUGH THAN THE CONSENSUS OF THE OTHER MODELS. OTHERWISE...TIMING AND PLACEMENT ARE QUITE SIMILAR AMONGST THE MODELS. ACCORDINGLY...HAVE FOLLOWED THE HRRR M0ST CLOSELY THROUGH THE FIRST PART OF THE SHORT TERM WITH A GENERAL BLEND FAVORED AFTER THAT. SENSIBLE WEATHER WILL FEATURE AN ACTIVE LATE AFTERNOON AND EARLY EVENING PERIOD AS CONVECTION MOVES THROUGH EASTERN KENTUCKY DRIVEN BY INSTABILITY AND DIFFERENTIAL HEATING AS WELL AS OUTFLOW FROM EARLIER STORMS. THE HIGH MOISTURE CONTENT IN THE AIR WILL MAKE HEAVY RAINS A THREAT. IN ADDITION...A FEW OF THE STRONGER STORMS COULD CONTAIN GUSTY WINDS WITH A SMALL POTENTIAL TO DO DAMAGE. WILL CONTINUE TO MENTION THIS CONCERN IN THE FORTHCOMING UPDATE TO THE HWO. THE INSTABILITY WILL WANE AFTER SUNSET...BUT THE APPROACHING SFC FRONT WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE THROUGH THE EVENING AND INTO THE EARLY OVERNIGHT PERIOD. DO EXPECT THE THUNDER TO BE MOSTLY GONE BY MIDNIGHT...THOUGH...SO HAVE DROPPED ITS MENTION IN THE WX GRIDS AFTER THAT TIME. PATCHY FOG WILL BE POSSIBLE AS WELL...POST FRONTAL...LATER TONIGHT...BUT PLENTY OF CLOUDS AROUND SHOULD KEEP THE VISIBILITIES FROM GETTING TOO LOW. A FEW SHOWERS MAY LINGER THROUGH FAR EASTERN KENTUCKY INTO THE DAY TUESDAY AS HIGH PRESSURE ONLY SLOWLY PUSHES INTO THE AREA. THIS HIGH WILL BRING IN DRIER AIR AND...EVENTUALLY... CLEARING SKIES FROM WEST TO EAST LATER TUESDAY. A BETTER CHANCE FOR FOG IN THE VALLEYS...PERHAPS LOCALLY DENSE...CAN THEN BE ANTICIPATED FOR LATER TUESDAY NIGHT INTO WEDNESDAY MORNING. STARTED WITH THE SHORTBLEND GUIDANCE THROUGH THE FIRST PART OF THE FORECAST FOR THE T/TD/WIND GRIDS FOLLOWED BY THE SUPERBLEND FOR THE REMAINDER OF THE TIME. DID MAKE SOME VERY MINOR CHANGES TO LOWS TONIGHT AND TUESDAY NIGHT BASED ON THE TERRAIN. AS FOR POPS...ENDED UP MOST SIMILAR TO A BLEND OF THE WETTER MAV AND DRIER MET NUMBERS TONIGHT AND TUESDAY WITH SINGLE DIGIT POPS FOR TUESDAY NIGHT IN LINE WITH GUIDANCE. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 251 PM EDT MON AUG 10 2015 DRY AND PLEASANT WEATHER IS ON TAP FOR THE EXTENDED PORTION OF THE FORECAST. A LARGE RIDGE OF HIGH PRESSURE IS FORECAST TO BECOME ESTABLISHED OVER THE EASTERN THIRD OF THE CONUS FROM EARLY WEDNESDAY ONWARD. THE RIDGE WILL USHER IN A MUCH COOLER AND DRIER AIR MASS THAN ANY WE HAVE SEEN IN THIS PART OF THE COUNTY IN RECENT WEEKS. BOTH DAY AND NIGHT TIME TEMPERATURES WILL BE RUNNING WELL BELOW AVERAGE THE FIRST COUPLE OF DAYS AND NIGHTS OF THE PERIOD. HIGHS ON TUESDAY AND WEDNESDAY ARE EXPECTED TO TOP OUT IN THE UPPER 70S FOR MOST LOCATIONS...WITH OVERNIGHT LOWS WEDNESDAY AND THURSDAY NIGHT DIPPING INTO THE UPPER 50S FOR EVERYWHERE...EXCEPT RIGHT ALONG THE TENNESSEE BORDER...WHERE A FEW READINGS AT OR JUST ABOVE 60 MIGHT BE REALIZED. NO PRECIPITATION IS IN THE FORECAST AT THIS POINT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 215 PM EDT MON AUG 10 2015 VFR CONDITIONS PREVAIL AT MOST SITES EARLY THIS AFTERNOON AS THE CONVECTION HASN/T BEEN TOO WIDESPREAD AS OF YET. HOWEVER...A HEALTHY CLUSTER OF SHOWERS AND STORMS ARE MOVING THROUGH THE CUMBERLAND VALLEY. LOWER CIG AND VIS CAN BE EXPECTED FOR THOSE LOCATIONS AS WELL AS OTHERS ACROSS THE FORECAST AREA WHEN THE COVERAGE BECOMES MORE EXTENSIVE. FOR THIS...HAVE INCLUDED A TEMPO TO IFR CONDITIONS WITH ANY STORMS. THE CONVECTION SHOULD BECOME MORE SCATTERED BY LATE AFTERNOON AND THROUGH THE EVENING WITH A LOSS OF THUNDER LIKELY FOLLOWING SUNSET. A FEW SHOWERS WILL CONTINUE WELL INTO THE NIGHT...THOUGH ALONG WITH LOWERING CIGS AND SOME MVFR FOG AT ALL SITES. CONDITIONS WILL IMPROVE BACK TO VFR BY MID MORNING ON TUESDAY. OUTSIDE OF ANY STORMS...WINDS WILL BE GENERALLY LIGHT THROUGH THE PERIOD FROM THE WEST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
301 PM EDT MON AUG 10 2015 .UPDATE... ISSUED AT 145 PM EDT MON AUG 10 2015 DID A QUICK UPDATE TO THE GRIDS TO REFLECT THE CURRENT POP PATTERN WITH SOME ADJUSTMENTS BASED ON THE LATEST HRRR INTO THE EVENING. ALSO FINE TUNED THE T/TD GRIDS PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 1120 AM EDT MON AUG 10 2015 14Z SFC ANALYSIS SHOWS A BROAD AREA OF LOW PRESSURE CROSSING THROUGH THE OHIO VALLEY NORTH OF KENTUCKY. A TRAILING COLD FRONT ASSOCIATED WITH THIS IS APPROACHING THE REGION. HOWEVER...AHEAD OF THIS BOUNDARY...AMPLE MOISTURE IS POOLING THROUGH EASTERN KENTUCKY WITH DEWPOINTS PREDOMINATELY IN THE LOWER 70S. MORNING BREAKS IN THE CLOUD COVER WILL HELP TO BUILD INSTABILITY THROUGH THE CWA AS TEMPERATURES ARE CURRENTLY IN THE UPPER 70S AND LOWER 80S ON THEIR WAY TO THE MID AND UPPER 80S. THE QUESTION IS WHETHER THE DEBRIS CLOUDS FROM THE EARLIER CONVECTION TO THE WEST WILL BE ENOUGH TO INHIBIT THE DEVELOPMENT OF WIDESPREAD AND ORGANIZED STORMS THROUGH THE AREA LATER THIS AFTERNOON. ALREADY A GROUP OF SHOWERS AND DEVELOPING STORMS ARE TRACKING INTO THE CUMBERLAND VALLEY. EXPECT THESE TO SPREAD INTO THE EARLY AFTERNOON WITH ADDITIONAL POCKETS OF CONVECTION EXPANDING TO THE NORTH AND EAST. THE LATEST HRRR MODEL AGREES WITH THIS SCENARIO WITH PEAK CONVECTIVE ACTIVITY TAKING PLACE OVER THE JKL CWA BETWEEN 19 AND 23Z. HAVE UPDATED THE GRIDS WITH THIS IN MIND AS WELL AS INFUSED THE LATEST SHORTBLEND GUIDANCE INTO THE T AND TD GRIDS. THOSE LATER ONES WERE UPDATED TO BETTER REFLECT THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS WITH A FRESHENED SET OF ZONES TO FOLLOW. UPDATE ISSUED AT 654 AM EDT MON AUG 10 2015 WSR-88D CONTINUES TO INDICATE SOME ISOLATED SHOWERS MOVING SOUTHEAST ACROSS PORTIONS OF EASTERN KY. EXPECT THIS MORNING SHOWER ACTIVITY TO REMAIN LIGHT. THE HEAVIER STORMS REMAINED SOUTH AND WEST OF THE REGION...AS MCS DIVED SOUTH TOWARD THE MORE UNSTABLE ENVIRONMENT WHERE UPPER 70S TO LOW 80 DEWPOINTS WERE REPORTED. STILL LOOKING AT INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS AS WE MOVE INTO THE AFTERNOON HOURS AHEAD OF A APPROACHING COLD FRONT. SOME MINOR UPDATES TO POPS AND THEN UPDATES TO TEMPS/DEWS/WINDS TO MATCH CURRENT CONDITIONS/TRENDS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 327 AM EDT MON AUG 10 2015 OVERALL MODELS REMAIN IN GOOD AGREEMENT WITH OVERARCHING SYNOPTIC PATTERN WITH TROUGHING CONTINUE TO DEEPEN IN THE EASTERN CONUS THROUGH THE PERIOD. THIS MORNING WE ARE BEING MET WITH A FEW SHOWERS SPREADING SE ACROSS PORTIONS OF EASTERN KY SEEN ON WSR- 88D. THIS HAS BEEN BROUGHT ON BY UPPER LEVEL WAVE AND INCREASING LOW LVL JET ACROSS THE OHIO/TN VALLEYS. THESE ARE DEVELOPING AHEAD OF AN APPROACHING SURFACE LOW PRESSURE AND COLD FRONT ACROSS THE MIDWEST THIS MORNING. WHILE WE DO HAVE SHOWERS AND PERHAPS A ISOLATED THUNDERSTORM THIS MORNING...BETTER CHANCES OF SHOWERS AND THUNDERSTORMS WILL EXIST AS WE MOVE INTO THE AFTERNOON AHEAD OF THE COLD FRONT. THE QUESTION IS HOW MUCH DOES ON GOING ACTIVITY AND CLOUD COVER PLAY ON THE OVERALL DESTABILIZATION...RIGHT NOW THIS LOOKS TO HAVE SOME AFFECTS BUT INCREASING LOW LEVEL JET AND SOME INSULATION LOOK TO BE ENOUGH TO FIRE OF STORMS THIS AFTERNOON. THIS LOOKS REASONABLE WITH CA MODELS SHOWING GOOD AGREEMENT OF BEST ACTIVITY GENERALLY AFTER 18Z. WHILE SOME OF THESE STORMS COULD BE STRONG...THINKING OVERALL SEVERE THREAT REMAINS LOW WITH SHEAR BEING MARGINAL AT BEST. THAT SAID MAIN THREAT WOULD BE ISOLATED DAMAGING WIND GUST...AND THIS LINES UP WELL WITH SPC THINKING AND OVERALL BROAD MARGINAL RISK. AFTER THIS SHOWER AND STORM ACTIVITY WILL WAIN IN THE EVENING AND OVERNIGHT HOURS AS FRONT SLOWLY MOVES EAST ACROSS THE REGION. MAINTAIN SOME INSTABILITY SHOWERS MAINLY IN THE FAR EAST THROUGH THE DAY ON TUESDAY. OTHERWISE SOME SPOTS ARE EXPECTED TO BEGIN THE DRYING OUT PROCESS IN THE WAKE OF THE COLD FRONT...AS WE TRANSITION TO W/NW FLOW. THE OTHER ISSUE IS HOW MUCH IF ANY FOG WILL BE SEEN EARLY TUESDAY GIVEN CLOUD COVER...SO RIGHT NOW LEFT OUT OF THE FORECAST GIVEN LOWER CONFIDENCE. THAT SAID VALLEYS AND AREAS THAT RECEIVED RAIN WILL HAVE THE BEST CHANCES OF SEEING REASONABLE PRODUCTION. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 251 PM EDT MON AUG 10 2015 DRY AND PLEASANT WEATHER IS ON TAP FOR THE EXTENDED PORTION OF THE FORECAST. A LARGE RIDGE OF HIGH PRESSURE IS FORECAST TO BECOME ESTABLISHED OVER THE EASTERN THIRD OF THE CONUS FROM EARLY WEDNESDAY ONWARD. THE RIDGE WILL USHER IN A MUCH COOLER AND DRIER AIR MASS THAN ANY WE HAVE SEEN IN THIS PART OF THE COUNTY IN RECENT WEEKS. BOTH DAY AND NIGHT TIME TEMPERATURES WILL BE RUNNING WELL BELOW AVERAGE THE FIRST COUPLE OF DAYS AND NIGHTS OF THE PERIOD. HIGHS ON TUESDAY AND WEDNESDAY ARE EXPECTED TO TOP OUT IN THE UPPER 70S FOR MOST LOCATIONS...WITH OVERNIGHT LOWS WEDNESDAY AND THURSDAY NIGHT DIPPING INTO THE UPPER 50S FOR EVERYWHERE...EXCEPT RIGHT ALONG THE TENNESSEE BORDER...WHERE A FEW READINGS AT OR JUST ABOVE 60 MIGHT BE REALIZED. NO PRECIPITATION IS IN THE FORECAST AT THIS POINT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 215 PM EDT MON AUG 10 2015 VFR CONDITIONS PREVAIL AT MOST SITES EARLY THIS AFTERNOON AS THE CONVECTION HASN/T BEEN TOO WIDESPREAD AS OF YET. HOWEVER...A HEALTHY CLUSTER OF SHOWERS AND STORMS ARE MOVING THROUGH THE CUMBERLAND VALLEY. LOWER CIG AND VIS CAN BE EXPECTED FOR THOSE LOCATIONS AS WELL AS OTHERS ACROSS THE FORECAST AREA WHEN THE COVERAGE BECOMES MORE EXTENSIVE. FOR THIS...HAVE INCLUDED A TEMPO TO IFR CONDITIONS WITH ANY STORMS. THE CONVECTION SHOULD BECOME MORE SCATTERED BY LATE AFTERNOON AND THROUGH THE EVENING WITH A LOSS OF THUNDER LIKELY FOLLOWING SUNSET. A FEW SHOWERS WILL CONTINUE WELL INTO THE NIGHT...THOUGH ALONG WITH LOWERING CIGS AND SOME MVFR FOG AT ALL SITES. CONDITIONS WILL IMPROVE BACK TO VFR BY MID MORNING ON TUESDAY. OUTSIDE OF ANY STORMS...WINDS WILL BE GENERALLY LIGHT THROUGH THE PERIOD FROM THE WEST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...DJ LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
215 PM EDT MON AUG 10 2015 .UPDATE... ISSUED AT 145 PM EDT MON AUG 10 2015 DID A QUICK UPDATE TO THE GRIDS TO REFLECT THE CURRENT POP PATTERN WITH SOME ADJUSTMENTS BASED ON THE LATEST HRRR INTO THE EVENING. ALSO FINE TUNED THE T/TD GRIDS PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 1120 AM EDT MON AUG 10 2015 14Z SFC ANALYSIS SHOWS A BROAD AREA OF LOW PRESSURE CROSSING THROUGH THE OHIO VALLEY NORTH OF KENTUCKY. A TRAILING COLD FRONT ASSOCIATED WITH THIS IS APPROACHING THE REGION. HOWEVER...AHEAD OF THIS BOUNDARY...AMPLE MOISTURE IS POOLING THROUGH EASTERN KENTUCKY WITH DEWPOINTS PREDOMINATELY IN THE LOWER 70S. MORNING BREAKS IN THE CLOUD COVER WILL HELP TO BUILD INSTABILITY THROUGH THE CWA AS TEMPERATURES ARE CURRENTLY IN THE UPPER 70S AND LOWER 80S ON THEIR WAY TO THE MID AND UPPER 80S. THE QUESTION IS WHETHER THE DEBRIS CLOUDS FROM THE EARLIER CONVECTION TO THE WEST WILL BE ENOUGH TO INHIBIT THE DEVELOPMENT OF WIDESPREAD AND ORGANIZED STORMS THROUGH THE AREA LATER THIS AFTERNOON. ALREADY A GROUP OF SHOWERS AND DEVELOPING STORMS ARE TRACKING INTO THE CUMBERLAND VALLEY. EXPECT THESE TO SPREAD INTO THE EARLY AFTERNOON WITH ADDITIONAL POCKETS OF CONVECTION EXPANDING TO THE NORTH AND EAST. THE LATEST HRRR MODEL AGREES WITH THIS SCENARIO WITH PEAK CONVECTIVE ACTIVITY TAKING PLACE OVER THE JKL CWA BETWEEN 19 AND 23Z. HAVE UPDATED THE GRIDS WITH THIS IN MIND AS WELL AS INFUSED THE LATEST SHORTBLEND GUIDANCE INTO THE T AND TD GRIDS. THOSE LATER ONES WERE UPDATED TO BETTER REFLECT THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS WITH A FRESHENED SET OF ZONES TO FOLLOW. UPDATE ISSUED AT 654 AM EDT MON AUG 10 2015 WSR-88D CONTINUES TO INDICATE SOME ISOLATED SHOWERS MOVING SOUTHEAST ACROSS PORTIONS OF EASTERN KY. EXPECT THIS MORNING SHOWER ACTIVITY TO REMAIN LIGHT. THE HEAVIER STORMS REMAINED SOUTH AND WEST OF THE REGION...AS MCS DIVED SOUTH TOWARD THE MORE UNSTABLE ENVIRONMENT WHERE UPPER 70S TO LOW 80 DEWPOINTS WERE REPORTED. STILL LOOKING AT INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS AS WE MOVE INTO THE AFTERNOON HOURS AHEAD OF A APPROACHING COLD FRONT. SOME MINOR UPDATES TO POPS AND THEN UPDATES TO TEMPS/DEWS/WINDS TO MATCH CURRENT CONDITIONS/TRENDS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 327 AM EDT MON AUG 10 2015 OVERALL MODELS REMAIN IN GOOD AGREEMENT WITH OVERARCHING SYNOPTIC PATTERN WITH TROUGHING CONTINUE TO DEEPEN IN THE EASTERN CONUS THROUGH THE PERIOD. THIS MORNING WE ARE BEING MET WITH A FEW SHOWERS SPREADING SE ACROSS PORTIONS OF EASTERN KY SEEN ON WSR- 88D. THIS HAS BEEN BROUGHT ON BY UPPER LEVEL WAVE AND INCREASING LOW LVL JET ACROSS THE OHIO/TN VALLEYS. THESE ARE DEVELOPING AHEAD OF AN APPROACHING SURFACE LOW PRESSURE AND COLD FRONT ACROSS THE MIDWEST THIS MORNING. WHILE WE DO HAVE SHOWERS AND PERHAPS A ISOLATED THUNDERSTORM THIS MORNING...BETTER CHANCES OF SHOWERS AND THUNDERSTORMS WILL EXIST AS WE MOVE INTO THE AFTERNOON AHEAD OF THE COLD FRONT. THE QUESTION IS HOW MUCH DOES ON GOING ACTIVITY AND CLOUD COVER PLAY ON THE OVERALL DESTABILIZATION...RIGHT NOW THIS LOOKS TO HAVE SOME AFFECTS BUT INCREASING LOW LEVEL JET AND SOME INSULATION LOOK TO BE ENOUGH TO FIRE OF STORMS THIS AFTERNOON. THIS LOOKS REASONABLE WITH CA MODELS SHOWING GOOD AGREEMENT OF BEST ACTIVITY GENERALLY AFTER 18Z. WHILE SOME OF THESE STORMS COULD BE STRONG...THINKING OVERALL SEVERE THREAT REMAINS LOW WITH SHEAR BEING MARGINAL AT BEST. THAT SAID MAIN THREAT WOULD BE ISOLATED DAMAGING WIND GUST...AND THIS LINES UP WELL WITH SPC THINKING AND OVERALL BROAD MARGINAL RISK. AFTER THIS SHOWER AND STORM ACTIVITY WILL WAIN IN THE EVENING AND OVERNIGHT HOURS AS FRONT SLOWLY MOVES EAST ACROSS THE REGION. MAINTAIN SOME INSTABILITY SHOWERS MAINLY IN THE FAR EAST THROUGH THE DAY ON TUESDAY. OTHERWISE SOME SPOTS ARE EXPECTED TO BEGIN THE DRYING OUT PROCESS IN THE WAKE OF THE COLD FRONT...AS WE TRANSITION TO W/NW FLOW. THE OTHER ISSUE IS HOW MUCH IF ANY FOG WILL BE SEEN EARLY TUESDAY GIVEN CLOUD COVER...SO RIGHT NOW LEFT OUT OF THE FORECAST GIVEN LOWER CONFIDENCE. THAT SAID VALLEYS AND AREAS THAT RECEIVED RAIN WILL HAVE THE BEST CHANCES OF SEEING REASONABLE PRODUCTION. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 327 AM EDT MON AUG 10 2015 QUIET LONG TERM PERIOD IN STORE AS AN EXPANSIVE UPPER LEVEL RIDGE OVER THE FOUR CORNERS REGION EXTENDS NORTHWARD INTO CENTRAL CANADA. WHILE A TROUGH REMAINS IN PLACE OVER THE EASTERN CONUS...THE HIGH AMPLITUDE RIDGE TO OUR WEST PLACES THE SOURCE REGION FOR OUR AIRMASS ALOFT OVER THE PRAIRIE PROVINCES OF CANADA...SO NOT MUCH OPPORTUNITY FOR MOISTURE RETURN. MODELS INDICATE A PIECE OF THE UPPER TROUGH OVER THE EAST WILL RETROGRADE SOUTHWEST AND POSSIBLY BREAK OFF INTO A WEAK CLOSED LOW OVER THE DEEP SOUTH. THIS MAY BRING ENOUGH LOW LEVEL MOISTURE IN OFF THE ATLANTIC TO CAUSE SOME ISOLATED DIURNAL CONVECTION OVER THE HIGHER TERRAIN OF THE SOUTHERN APPALACHIANS AT TIMES...BUT NOT LIKELY AFFECTING OUR AREA. THE NET RESULT SHOULD BE A DRY FORECAST WITH PLEASANT TEMPS AND HUMIDITY MID WEEK SLOWLY MODERATING BACK TO SEASONAL NORMS BY THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 215 PM EDT MON AUG 10 2015 VFR CONDITIONS PREVAIL AT MOST SITES EARLY THIS AFTERNOON AS THE CONVECTION HASN/T BEEN TOO WIDESPREAD AS OF YET. HOWEVER...A HEALTHY CLUSTER OF SHOWERS AND STORMS ARE MOVING THROUGH THE CUMBERLAND VALLEY. LOWER CIG AND VIS CAN BE EXPECTED FOR THOSE LOCATIONS AS WELL AS OTHERS ACROSS THE FORECAST AREA WHEN THE COVERAGE BECOMES MORE EXTENSIVE. FOR THIS...HAVE INCLUDED A TEMPO TO IFR CONDITIONS WITH ANY STORMS. THE CONVECTION SHOULD BECOME MORE SCATTERED BY LATE AFTERNOON AND THROUGH THE EVENING WITH A LOSS OF THUNDER LIKELY FOLLOWING SUNSET. A FEW SHOWERS WILL CONTINUE WELL INTO THE NIGHT...THOUGH ALONG WITH LOWERING CIGS AND SOME MVFR FOG AT ALL SITES. CONDITIONS WILL IMPROVE BACK TO VFR BY MID MORNING ON TUESDAY. OUTSIDE OF ANY STORMS...WINDS WILL BE GENERALLY LIGHT THROUGH THE PERIOD FROM THE WEST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...DJ LONG TERM...ABE AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1217 PM EDT MON AUG 10 2015 .SYNOPSIS... A COLD FRONT APPROACHES FROM THE NORTHWEST TODAY...CROSSING THE MID ATLANTIC TONIGHT INTO TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY...REMAINING OVER THE REGION INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A QUICK UPDATE THIS MORNING TO FOCUS SHOWER COVERAGE ACROSS THE SRN PIEDMONT...SCNTRL VA...AND SRN RICHMOND METRO AREAS THROUGH THE REST OF THIS MORNING BEFORE SHOWERS DISSIPATE. PREVIOUS DISCUSSION (651 AM)...RADAR TRENDS INDICATE SHOWERS HOLDING TOGETHER BETTER THAN EXPECTED OVER AN INCREASINGLY MOIST AIR MASS. LATEST RAP GUIDANCE DEPICTS WEAK VORT MAX OVER THE REGION...PROVIDING SUBTLE FORCING OVER AN AREA OF ISENTROPIC LIFT...HELPING DRIVE THE SHOWERS. THIS LIFT IS PROGGED TO SPREAD NEWD ACROSS CENTRAL VA THRU MID MORNING. HIGH PRESSURE ALONG THE COAST WILL BEGIN TO WIN OUT...HELPING ERODE THE SHOWERS AS THEY SPREAD EAST OF INTERSTATE 95. MID LEVEL CLOUDS HAVE ALSO OVERSPREAD THE AREA...RESULTING IN A MOSTLY CLOUDY SKY (PARTLY CLOUDY SOUTHEAST). BASED ON CURRENT PRECIP AND LATEST STATISTICAL GUIDANCE...HAVE LOWERED TEMPS A FEW DEGS ACROSS THE PIEDMONT INTO CENTRAL VA. HIGHS IN THE LOW TO MID 80S. PREVIOUS DISCUSSION (407 AM)...LATEST REGIONAL RADAR MOSAIC DEPICTS AN AREA OF SHOWERS OVER THE ERN VA PIEDMONT EARLY THIS MORNING...SLOWING SPREADING EWD. THIS IN ASSOCIATION WITH AN AREA OF ISENTROPIC LIFT AND WEAKENING ENERGY ALOFT. EXPECT THIS AREA OF SHOWERS TO DISSIPATE AS IT SPREADS EWD INTO THE LOCAL PIEDMONT COUNTIES AS THE ENERGY ALOFT WEAKENS. HOWEVER...CLOUD COVER WILL CONTINUE TO OVERSPREAD MUCH OF THE AREA THIS MORNING...RESULTING IN A MOSTLY CLOUDY SKY. OTHERWISE...MID- LEVEL HEIGHT FALLS OVER THE MID- ATLANTIC REGION HAS ALLOWED MOISTURE TO RETURN EARLY THIS MORNING...WITH PWATS PROGGED AROUND 1.5 TO 1.8 INCHES AND DEWPOINTS WARMING INTO THE MID 60S. AT THE SFC...HIGH PRESSURE HAS ALIGNED ALONG THE COAST WITH A WARM FRONT LOCATED OVER THE OH/KY VALLEYS. A COLD FRONT IS RIGHT ON ITS HEELS OVER THE MIDWEST. FOR TODAY...A MORE POTENT SHORTWAVE TROUGH APPROACHES THE REGION FROM THE NW AS THE PARENT TROUGH CONTINUES TO DIG OVER THE ERN GREAT LAKES. THE MIDWEST COLD FRONT REACHES THE OH VALLEY LATE TODAY. EXPECT MOSTLY CLOUDY...BUT GENERALLY DRY CONDITIONS THIS MORNING. WILL MAINTAIN SLIGHT CHANCE POPS OVER THE PIEDMONT DUE TO THE AFOREMENTIONED WEAKENING WAVE AND ISENTROPIC LIFT. HIGH PRESSURE PUSHES OFFSHORE THIS AFTERNOON...OPENING THE DOOR FOR BETTER MOISTURE RETURN. H85 FLOW INCREASES...WITH PWATS PROGGED TO REACH ~2 INCHES THIS AFTERNOON. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN THIS AFTERNOON ALONG THE WARM FRONT AND LEAD SHORTWAVE...SPREADING EWD DURING THE LATE AFTERNOON. HAVE RETAINED CHANCE POPS GENERALLY ALONG AND WEST OF INTERSTATE 95...BUMPING UP TO LIKELY IN THE NW PIEDMONT COUNTIES. ERN PORTIONS WILL LIKELY BECOME PARTLY TO MOSTLY SUNNY BY AFTERNOON...WHILE WRN PORTIONS REMAIN MOSTLY CLOUDY. THIS WILL KEEP HIGHS IN THE LOW 80S THERE...WHILE AREA FARTHER EAST RISE INTO THE MID/UPPER 80S. LOUISA AND FLUVANNA COUNTIES MAY STRUGGLE TO GET OUT OF THE UPPER 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... STRONGER FORCING ARRIVES TONIGHT AS THE TROUGH CONTINUES TO DIG SOUTHEAST AND THE WIND FIELD STRENGTHENS ALOFT. THE WARM FRONT CROSSES THE REGION EARLY TONIGHT AS THE COLD FRONT LOCATES CENTRAL APPALACHIANS. A WARM/HUMID AND MARGINALLY UNSTABLE AIR MASS WILL BE IN PLACE OVER THE LOCAL AREA AHEAD OF THE WARM FRONT. THE RESULT WILL BE WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS. LIKELY POPS HAVE BEEN RETAINED. LATEST SREF GUIDANCE CONTINUES TO INDICATE STRONG MOISTURE FLUX (ON THE ORDER OF +4 TO +5 STD DEV) OVERNIGHT. HEAVY RAIN WORDING HAS BEEN RETAINED DUE TO THE COMBINATION OF STRONG FORCING AND MOISTURE FLUX. MBE/CORFIDI VECTORS AND FLOW INDICATE GOOD STORM MOTION...WHICH WILL LIMIT THE FLOODING POTENTIAL. FFG HAS ALSO RECOVERED FOLLOWING LAST WEEKS RAINFALL. MARGINAL SHEAR MAY PRODUCE SOME GUSTY WINDS UNDER THE STRONGEST STORMS. LOWS FORECAST IN THE LOW 70S. THE COLD FRONT PUSHES ACROSS THE LOCAL AREA TUESDAY AFTERNOON/EVENING...AND PUSHES OFFSHORE TUESDAY NIGHT. SHOWERS AND SOME EMBEDDED TSTMS SHOULD CONTINUE TUESDAY MORNING ACROSS ERN PORTIONS. HOWEVER...HEAVY RAIN POTENTIAL WILL DIMINISH AND THE MOISTURE FLUX ANOMALIES RELAX. ANOTHER ROUND OF SHOWERS/THUNDERSTORMS IS EXPECTED BY AFTERNOON AHEAD OF THE COLD FRONT. A WARM/MOIST AIR MASS REMAINS OVER THE REGION...BUT INSTABILITY WILL LARGELY BE LIMITED BY ANY CLEARING. MODELS AND BUFR SOUNDINGS INDICATE A DRY SLOT/MID LEVEL DRYING TUE AFTERNOON...WHICH WOULD RESULT IN BETTER INSTABILITY AND CHANCES FOR THUNDER. STICKING WITH THE LATEST SREF...MLCAPE VALUES PROGGED AROUND 1K J/KG TUE AFTERNOON. EFFECTIVE SHEAR ALSO EXPECTED IN THE 20 TO 30 KT RANGE. STRONG GUSTY WINDS WILL BE THE MAIN THREAT ALONG WITH LOCALLY HEAVY RAINFALL. CHC POPS WILL BE CONTINUED THROUGH THE AFTERNOON INLAND...WITH LIKELY NEAR THE COAST. TRIMMED BACK POPS SLIGHTLY...WITH HIGHS GENERALLY IN THE MID 80S. SHOWERS/TSTMS CONTINUE INTO TUESDAY EVENING...BEFORE TAPERING OFF NW- SE DURING THE LATE EVENING AND OVERNIGHT HOURS. HIGH PRESSURE AND A DRIER AIRMASS BUILDS INTO THE REGION WEDNESDAY. SOME HIGHER LOW- LEVEL MOISTURE IS EXPECTED TO LINGER ACROSS FAR SE VA/NE NC WEDNESDAY...SO A SLIGHT CHC POP FOR SHOWERS/TSTMS WILL BE FORECAST FOR THESE LOCATIONS. LOWS WEDNESDAY MORNING RANGE FROM THE MID 60S NW...TO THE LOW 70S SE. 850MB TEMPERATURES OF 14-16C SUPPORT HIGHS IN THE LOW/MID 80S. SREF/GEFS/WPC PROBABILITIES INDICATE HIGH PROBS FOR GREATER THAN ONE HALF INCH RAINFALL AMOUNTS ACROSS THE ENTIRE LOCAL AREA. PROBS DROP OFF WITH HIGHER QPF AMOUNTS...WITH ONLY A SLIGHT CHANCE OVER THE NE COUNTIES FOR AOA 1 INCH. HOWEVER...LOCALIZED AMOUNTS GREATER THAN ONE INCH ARE EXPECTED...ESPECIALLY UNDER STRONGER THUNDERSTORMS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE BUILDS BACK INTO THE MID ATLANTIC REGION LATE WED NIGHT INTO FRI...THUS SHUNTING THE STALLED SFC FRONT ALONG THE CAROLINA COAST FARTHER SWD AND AWAY FROM THE FORECAST AREA. OVERALL FORECAST WILL BE DRY WITH TEMPERATURES CLOSE TO SEASONAL NORMALS AND GENERALLY COMFORTABLE CONDITIONS. LONG RANGE MODELS BEGIN TO BRING UPPER LEVEL TROUGHING ACROSS THE NE CONUS ON SAT...HOWEVER THEY DIFFER ON HOW DEEP/FAR SOUTH THE TROUGHING EXTENDS INTO THE MID ATLANTIC REGION. LEANED TWD A DRY SOLUTION FOR NOW WITH A SLIGHT WARMING TREND. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... VFR CNDTNS XPCTD THRU MOST OF THE TAF PRD DESPITE A WEAK DISTURBANCE MOVING ACROSS THE RGN TDY. TSCTNS SHOWING PLNTY OF MID LEVEL MSTR WITH THIS FEATURE ALONG WITH SCT SHWRS MOVG EAST OF THE MTS THIS MORNING. KEPT SCT TO BKN CLDS AT 5K-12K FT. HIGH RES MODELS NOW INDCT THAT RIC SEES A FEW HRS PRD OF RAIN AT BEGINNING OF TAF PRD... BUT CIGS AND VSBY XPCTD TO REMAIN IN MVFR TO VFR RANGE. SBY/PHF MAY SEE SOME -RA BUT NO VSBY RESTRICTIONS XPCTD THIS MORNING. ADDNTL SHWRS DVLP W-E AFTR 06Z AND MOVE EAST AS MSTR OVRSPRDS THE AREA AHEAD OF APPRCHG CDFRNT. OUTLOOK...THE COLD FRONT CROSSES THE REGION LATE TUESDAY WITH CHC CONVECTION. DRY WEATHER RETURNS WEDNESDAY THROUGH FRIDAY. && .MARINE... SCA OVER THE OCEAN HAS BEEN CANCELLED AS SEAS HAVE FAILED TO STAY UP NEAR 5 FT. OTHER SCA OVER THE BAY REMAINS IN PLACE AND MAY HAVE TO ISSUE OTHER HEADLINES WITH THIS AFTERNOONS FORECAST PACKAGE. PREVIOUS DISCUSSION... SEAS SLOW TO SUBSIDE AND STILL AVG 4-5 FT GIVEN THE PERSISTENT (ALBEIT LIGHT) ONSHORE FLOW. GIVEN THE PROGGED SWELL DRCTN...SEAS WILL LIKELY REMAIN AT THESE LEVELS MOST OF THE DAY. THUS...HAVE XTNDD SCA HEADLINES FOR SEAS DESPITE LIGHT ESE FLOW. THNKG IS FOR OFFSHORE SEAS TO DROP BLO 5 FT BY TONIGHT ENDING THE CRNT SCA HEADLINES...HOWEVER DATA SUGGESTS SEAS BLDG BACK TO NR 5 FT OUT NEAR 20 NM ACROSS NRN CSTL WTRS TUE. WNDS BECOME SRLY TONIGHT THEN SW ON TUE AHEAD OF APPRCHG CD FRNT. SRLY CHANNELING NOTED IN ALL THE DATA BUT THE CHALLENGE WILL BE TO DETERMINE WHICH AREAS SEE WNDS AT SCA LVLS. HIGHEST CONFIDENCE FOR THIS TO OCCUR IS ACROSS THE MIDDLE CHES BAY (ANZ630) TONIGHT AND TUE SO HAVE ISSUED SCA HEADLINES FOR THIS ZONE. CONFIDENCE NOT HIGH ENUF TO PUT THE SRN CHES BAY IN ANY HEADLINE ATTM SO HAVE CAPPED THE SUSTAINED WINDS AT 15 KTS AND WILL LET THE DAY SHIFT REVIEW THE 12Z DATA TO DETERMINE IF ANY SCA`S ARE NEEDED THERE AHEAD OF THE FRNT. CDFRNT CROSSES THE WATERS LATE TUE NIGHT SHFTG WNDS TO THE NORTH WED. NOT MUCH OF A SURGE NOTED IN THE 12Z DATA BEHIND THE FROPA SO NO SCA HEADLINE ANTICIPATE ATTM. HIGH PRS TO THE NORTH BLDS ACROSS THE WTRS FOR THE REST OF THE WEEK WITH WNDS/SEAS BLO SCA THRESHOLDS. INCREASED RIP CURRENT THREAT TO MODERATE GIVEN NEARSHORE WAVES BTWN 3-4 FT AND A PERSISTENT ONSHORE SWELL. NOT OUT OF THE QSTN THAT A HIGH RISK MAY BE NEEDED ACROSS THE NRN OUTER BANKS TODAY AFTER GETTING SOME FEEDBACK FROM THE BEACH AREAS LATER THIS MORNING. && .TIDES/COASTAL FLOODING... A COASTAL FLOOD STATEMENT HAS BEEN ISSUED FOR THE BAY SIDE OF THE LWR MD ERN SHORE THRU MIDDAY...SPECIFICALLY FOR BISHOPS HEAD WHERE LEVELS ARE EXPECTED TO BE ABOUT A TENTH OF A FOOT BLO MINOR FLOOD THRESHOLDS. PREVIOUS DISCUSSION... AS EXPECTED...WATER HAVING A TUFF TIME GETTING OUT OF THE CHES BAY WITH THE WATER LEVELS ACROSS THE MIDDLE OF THE CHES BAY REMAINED ELEVATED DURING THE PAST HIGH TIDE CYCLE. BOTH BISHOPS HEAD AND CAMBRIDGE TOPPED OUT JUST BLO MINOR FLOODING THRESHOLDS. TONIGHTS HIGH TIDE CYCLE COMES CLOSE ONCE AGAIN TO MINOR FLOODING THRESHOLDS IN SVRL AREAS OF THE CHES BAY. DESPITE TIDAL ANOMALIES REMAINING AT 0.5 TO 1.0 FT ABOVE NORMAL OVR THE NEXT FEW HIGH TIDE CYCLES...THE VALUES SHOULD TOP OUT BLO MINOR FLOODING THRESHOLDS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 4 PM EDT TUESDAY FOR ANZ630. && $$ SYNOPSIS...AJZ/SAM NEAR TERM...AJZ/BMD/SAM SHORT TERM...AJZ/SAM LONG TERM...BMD AVIATION...MPR MARINE...MAS/MPR TIDES/COASTAL FLOODING...MAS/MPR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
356 PM EDT MON AUG 10 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 355 PM EDT MON AUG 10 2015 BEEN A SLOW EAST-SOUTHEAST PUSH TO THE COLD FRONT OVER EASTERN CWA TODAY. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE FIRED ALONG AND AHEAD OF FRONT MOST OF THE DAY...ONLY CLEARING KESC/KISQ/KERY WITHIN LAST COUPLE HOURS. MOST LIGHTNING WITH ANY CELLS HAS BEEN OVER BAY OF GREEN BAY NEAR SHORELINE OF MENOMINEE COUNTY. SCATTERED CU LEFT IN WAKE OF FRONT ELSEWHERE...THOUGH STRATUS AND FOG IS OVER EASTERN LK SUPERIOR AND ADJACENT SHORELINE FROM HARVEY TO MUNISING TO GRAND MARAIS AND WHITEFISH POINT. VISIBLE SATELLITE AND MODEL GUIDANCE POINT TO FOG SHIRNKING IN COVERAGE THROUGH THE EVENING AND EVENTUALLY DISIPPATING OVERNIGHT. DENSE FOG ADVISORY FOR EASTERN LK SUPERIOR GOES UNTIL 11 PM THIS EVENING. EVENING SHIFT CAN ALTER THAT HEADLINE TIMING BASED ON OBSERVATION TRENDS. LOOKING UPSTREAM OVER NORTHERN ONTARIO...A SHORTWAVE IS DROPPING TOWARD THUNDER BAY AND ISLE ROYALE. ENVIRONMENT CANADA/NWS DLH/NWS MQT COMPOSITE RADAR LOOP SHOWS NUMEROUS SHRA AND SOME TSRA SPILLING TOWARD ISLE ROYALE...BUT GREATER COVERAGE IS STAYING UPSTREAM. WILL CARRY SCATTERED SHOWERS AND THUNDERSTORMS OVER ISLE ROYALE INTO THE EVENING. NAM AND GEM-REGIONAL AND THE HRRR INDICATE REMNANTS OF THE UPSTREAM SHOWERS MAY REACH WEST AND NORTHWEST CWA THIS EVENING. AT THE LEAST...WILL SEE SCT-BKN MID CLOUDS. REST OF OVERNIGHT APPEARS QUIET. GRADIENT NORTH TO NORTHWEST WINDS BETWEEN HIGH PRESSURE FM NORTHERN MANITOBA TO THE NORTHERN PLAINS AND LOW OVER JAMES BAY SHOULD RESTRICT IDEAL RADIATIONAL COOLING AND SIGNIFICANT FOG POTENTIAL. COULD SEE PARTCHY FOG THOUGH WHERE THERE WAS SOME RAIN TODAY. MAIN ISSUE ON TUESDAY WILL BE LOW CLOUDS. CONSENSUS OF SHORT RANGE MODELS TRENDING TOWARD GREATER CLOUD COVER AND BASED ON WIDESPREAD STRATUS OVER NORTHERN ONTARIO THIS AFTN THAT IS FORECAST TO SETTLE SOUTHWARD INTO TUESDAY...THE TREND MAKES A LOT OF SENSE. BUMPED UP SKY COVER AND ALSO KEPT SMALL MENTION OF DRIZZLE MAINLY IN THE MORNING FOR NCNTRL UPR MICHIGAN WITH NORTHERLY UPSLOPE FLOW. GUSTY NORTH-NORTHWEST WINDS...POSSIBLY UP TO 25 MPH...WILL ALSO CAUSE SOME IMPACT...MAINLY TO MARINE INTERESTS ALONG LK SUPERIOR SHORE TO EAST OF BIG BAY AND MARQUETTE AND ALSO ON BAY OF GREEN BAY AND NORTHERN LK MICHIGAN. THERMAL TROUGH AT H85 OVER THE AREA SHOULD ALLOW STRATUS AND STRATOCU CLOUDS TO PERSIST THROUGH MUCH OF THE DAY. TEMPS COOLEST NEAR LK SUPERIOR EAST OF MARQUETTE WITH LOW 60S. TEMPS OVER SCNTRL CWA COULD STILL REACH MID 70S. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 316 PM EDT MON AUG 10 2015 AT THE START OF THE LONG TERM PERIOD THE UPPER GREAT LAKES REGION WILL BE UNDER NORTHWESTERLY FLOW ALOFT...AS AN UPPER TROUGH WILL BE LOCATED OVER WESTERN QUEBEC AND AN UPPER RIDGE OVER THE U.S. ROCKIES AND CANADIAN PRAIRIES. THIS NORTHWESTERLY FLOW ALOFT WILL PERSIST THROUGH MUCH OF THE LONG TERM PERIOD...AS THE QUEBEC TROUGH IS RE-ENFORCED BY WAVE THE CURRENTLY OVER SOUTHEAST ALASKA. THAT WILL LEAD TO A COUPLE OPPORTUNITIES FOR SHOWERS/THUNDERSTORMS BUT HIGH PRESSURE WILL CONTROL MUCH OF THE LONG TERM FORECAST. A RIDGE WILL BE OVER THE UPPER GREAT LAKES AT THE START OF THE PERIOD...FROM A HIGH IN THE CENTRAL MISSISSIPPI VALLEY...WHICH WILL LEAD TO A MOSTLY CLEAR START TO TUESDAY NIGHT. THAT WILL BE SHORT LIVED...AS A WEAK SHORTWAVE DIVES SOUTHEAST OUT OF FAR WESTERN ONTARIO AND ACROSS NORTHWESTERN LAKE SUPERIOR. EXPECT SHOWERS AND MAYBE A FEW THUNDERSTORMS TO BE ASSOCIATED WITH THIS WAVE...AS THERE IS DECENT 925-700MB WARM AIR ADVECTION WITH IT. THIS SHOULD ARRIVE LATE IN THE NIGHT TOWARDS THE KEWEENAW AND THEN SHIFT SOUTHEAST THROUGH THE CENTRAL U.P. DURING THE DAY ON WEDNESDAY. MODELS ARE SHOWING ENOUGH OF A SIGNAL IN WITH THE WARM AIR ADVECTION TO TREND POPS UP TO CHANCES FOR PARTS OF THE AREA ON WEDNESDAY. WHILE MUCAPE VALUES ARE NOT OVERLY IMPRESSIVE LATE TUESDAY NIGHT INTO WEDNESDAY...THINK THE STEEPENING LAPSE RATES ON THE WESTERN EDGE OF THE WARM AIR ADVECTION WOULD SUPPORT THERE BEING SOME THUNDERSTORMS AND HAVE ADDED A SLIGHT CHANCE OF THUNDER ALONG THE WESTERN EDGE OF THE POPS. WHILE THAT WAVE WILL QUICKLY SLIDE TO THE SOUTHEAST...THEN NEXT WAVE AND ASSOCIATED COLD FRONT (FROM A LOW MOVING THROUGH NORTHERN ONTARIO) WILL MOVE SOUTHEAST THROUGH THE CWA LATE WEDNESDAY NIGHT AND THURSDAY. THERE ARE STILL SOME TIMING DIFFERENCES IN THE MODELS...WITH THEM SPEEDING IT UP SOME FROM PREVIOUS RUNS. THIS WILL LIKELY PUSH THE FRONT AND A BULK OF THE PRECIPITATION THROUGH THE AREA ON THURSDAY MORNING AND INTO EARLY THURSDAY AFTERNOON. WILL SHOW CHANCE POPS MOVING THROUGH THE AREA DURING THAT PERIOD...WITH THE HIGHEST NEAR THE LAKE MICHIGAN SHORELINE WITH THE ADDED HELP OF DIURNAL HEATING. WILL HAVE THUNDER CHANCES FOLLOW THE POPS...AS THERE ARE FAIRLY STEEP LAPSE RATES (7 C/KM OR HIGHER) ALONG AND AHEAD OF THE FRONT. IF THE FRONT MOVES THROUGH A LITTLE SLOWER...THERE WOULD BE ENOUGH SHEAR TO SUPPORT STRONGER THUNDERSTORMS OVER THE SOUTHEASTERN U.P. ON THURSDAY AFTERNOON. BEHIND THE COLD FRONT...THERE ARE SOME HINTS IN THE MODELS OF A VERY WEAK SHORTWAVE BRUSHING THE AREA ON THURSDAY NIGHT...OTHERWISE...HIGH PRESSURE FROM THE CANADIAN PRAIRIES WILL MOVE SOUTHEAST OVER THE UPPER GREAT LAKES REGION ON FRIDAY AND REMAIN INTO SATURDAY. THAT SHOULD LEAD TO A NICE COUPLE OF DAYS IN THE U.P. WITH HIGHS IN THE 70S TO AROUND 80 DEGREES WITH AFTERNOON LAKE BREEZES. THE HIGH WILL START TO SHIFT TO THE SOUTHEAST ON SATURDAY NIGHT AS THE UPPER RIDGE AXIS CROSSES THE UPPER GREAT LAKES REGION. BEHIND THAT UPPER RIDGE...ANOTHER TROUGH WILL MOVE THROUGH THE AREA FOR LATER SUNDAY AND INTO SUNDAY NIGHT AND WILL SPREAD CHANCE POPS EAST ACROSS THE AREA FOR THAT TIME FRAME. AT THIS TIME...MODELS ARE CONSISTENT ON IT QUICKLY SHIFTING EAST AND LEADING TO A MAINLY DRY MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 146 PM EDT MON AUG 10 2015 VFR CONDITIONS EXPECTED THROUGH TAF PERIOD AT KIWD AND KCMX. SCT-MID CLOUDS WILL AFFECT BOTH SITES AT TIMES...ESPECIALLY TONIGHT AS SHRA DISSIPATE WHILE MOVING OUT OF NORTHEAST MN AND NORTHERN ONTARIO. AT KSAW...VFR CONDITNONS SHOULD PREVAIL UNTIL LATE TONIGHT WHEN LOW CLOUDS CURRENTLY OVER NORTHERN ONTARIO DROP ACROSS LK SUPERIOR AND MOVE INTO NORTHERN UPR MICHIGAN ON NORTH WINDS. CIGS SHOULD SETTLE INTO LOW MVFR RANGE AROUND SUNRISE ON TUESDAY...WITH SOME POTENTIAL OF IFR CIGS THROUGH TUE MORNING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 355 PM EDT MON AUG 10 2015 NW WINDS UP TO 20 KTS ARE EXPECTED THROUGH TUESDAY. STRONGEST PUSH OF WINDS WILL OCCUR TONIGHT INTO TUESDAY MORNING OVER EAST HALF. DENSE FOG WILL GRADUALLY DIMINISH BY OVERNIGHT TONIGHT. ARRIVAL OF SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE UP TO 20 KTS OUT OF THE SW INTO THU AHEAD OF THE NEXT APPROACHING COLD FRONT. WINDS WILL DIMINISH TO LESS THAN 15 KTS ON FRI AS HIGH PRESSURE BUILDS INTO THE UPPER LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ249>251- 266-267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLA LONG TERM...SRF AVIATION...JLA MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
316 PM EDT MON AUG 10 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 509 AM EDT MON AUG 10 2015 WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A RIDGE OVER THE ROCKIES WITH DOWNSTREAM TROF BEGINNING TO DEEPEN FROM HUDSON BAY S INTO THE GREAT LAKES. IN THE DEVELOPING NW FLOW INTO THE GREAT LAKES...THERE IS ONE SHORTWAVE OF NOTE UPSTREAM E OF LAKE WINNIPEG ALONG THE ONTARIO/MANITOBA BORDER. CLOSER TO HOME...SCT SHRA CONTINUE EARLY THIS MORNING OVER ROUGHLY THE E HALF UPPER MI...AHEAD OF COLD FRONT. WILL CONTINUE TO CARRY SCT SHRA OVER THE ERN FCST AREA THIS MORNING AHEAD OF SLOW MOVING COLD FRONT. MIGHT BE A FEW RUMBLES OF THUNDER. WHERE CLOUDS SCATTER OUT...EXPECT SOME FOG UNTIL MID MORNING... ESPECIALLY IN THOSE AREAS WHERE RAINFALL HAS OCCURRED OVER THE LAST 12HRS. THIS AFTN...UNDER NNW FLOW...LAKE BREEZE COMPONENTS TO WIND WILL LEAD TO AN AREA OF CONVERGENCE IN SCNTRL UPPER MI. WITH POTENTIAL OF 50-200J/KG OF MLCAPE PER GFS/RAP/HRRR...ISOLD SHRA/TSTM MAY DEVELOP (NAM LOOKS WAY TOO HIGH WITH MLCAPES OVER 1000J/KG). WITH MOST OF THE HIGH RES MODEL GUIDANCE SHOWING SOME CONVECTION IN THAT AREA...WILL INCLUDE SCHC TO LOW CHC POPS IN SCNTRL UPPER MI THIS AFTN. AHEAD OF THE LAKE BREEZE OFF LAKE SUPERIOR...MAY SEE A FEW SHRA/TSRA E TOWARD KISQ/KERY AS WELL. AS SHORTWAVE CURRENTLY E OF LAKE WINNIPEG DROPS SE...REACHING WRN LAKE SUPERIOR THIS EVENING...THERE SHOULD BE QUITE A BIT OF SHRA AND SOME TSTMS DEVELOPING NW OF LAKE SUPERIOR THIS AFTN. THIS CONVECTION WILL SPREAD OUT OVER NW LAKE SUPERIOR IN THE AFTN. NOT SURE HOW FAR THIS ACTIVITY WILL SPREAD BEFORE DISSIPATING OVER THE COOLER MARINE LAYER. HOWEVER...WITH WATER NOT AS COLD AS EARLIER IN THE SUMMER AND WITH SUPPORT FROM DECENT LOOKING SHORTWAVE...SOME OF THIS ACTIVITY CERTAINLY HAS THE POTENTIAL TO SURVIVE IN A WEAKENED STATE INTO NW UPPER MI LATE THIS AFTN/EARLY EVENING. ANY -SHRA THAT SURVIVE THE TRIP ACROSS THE LAKE INTO NW UPPER MI WILL DISSIPATE THIS EVENING AS SHORTWAVE QUICKLY MOVES E OF THE AREA. THIS WILL LEAD TO A QUIET OVERNIGHT. SINCE GFS AND ESPECIALLY NAM SUGGEST AN INCREASE IN LOW CLOUDS OCCURRING LATE IN THE NIGHT INTO TUE MORNING...CLOUD COVERAGE WAS TRENDED UP OVERNIGHT... ESPECIALLY ACROSS THE N WHERE UPSLOPE WIND SHOULD AID CLOUD DEVELOPMENT. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 316 PM EDT MON AUG 10 2015 AT THE START OF THE LONG TERM PERIOD THE UPPER GREAT LAKES REGION WILL BE UNDER NORTHWESTERLY FLOW ALOFT...AS AN UPPER TROUGH WILL BE LOCATED OVER WESTERN QUEBEC AND AN UPPER RIDGE OVER THE U.S. ROCKIES AND CANADIAN PRAIRIES. THIS NORTHWESTERLY FLOW ALOFT WILL PERSIST THROUGH MUCH OF THE LONG TERM PERIOD...AS THE QUEBEC TROUGH IS RE-ENFORCED BY WAVE THE CURRENTLY OVER SOUTHEAST ALASKA. THAT WILL LEAD TO A COUPLE OPPORTUNITIES FOR SHOWERS/THUNDERSTORMS BUT HIGH PRESSURE WILL CONTROL MUCH OF THE LONG TERM FORECAST. A RIDGE WILL BE OVER THE UPPER GREAT LAKES AT THE START OF THE PERIOD...FROM A HIGH IN THE CENTRAL MISSISSIPPI VALLEY...WHICH WILL LEAD TO A MOSTLY CLEAR START TO TUESDAY NIGHT. THAT WILL BE SHORT LIVED...AS A WEAK SHORTWAVE DIVES SOUTHEAST OUT OF FAR WESTERN ONTARIO AND ACROSS NORTHWESTERN LAKE SUPERIOR. EXPECT SHOWERS AND MAYBE A FEW THUNDERSTORMS TO BE ASSOCIATED WITH THIS WAVE...AS THERE IS DECENT 925-700MB WARM AIR ADVECTION WITH IT. THIS SHOULD ARRIVE LATE IN THE NIGHT TOWARDS THE KEWEENAW AND THEN SHIFT SOUTHEAST THROUGH THE CENTRAL U.P. DURING THE DAY ON WEDNESDAY. MODELS ARE SHOWING ENOUGH OF A SIGNAL IN WITH THE WARM AIR ADVECTION TO TREND POPS UP TO CHANCES FOR PARTS OF THE AREA ON WEDNESDAY. WHILE MUCAPE VALUES ARE NOT OVERLY IMPRESSIVE LATE TUESDAY NIGHT INTO WEDNESDAY...THINK THE STEEPENING LAPSE RATES ON THE WESTERN EDGE OF THE WARM AIR ADVECTION WOULD SUPPORT THERE BEING SOME THUNDERSTORMS AND HAVE ADDED A SLIGHT CHANCE OF THUNDER ALONG THE WESTERN EDGE OF THE POPS. WHILE THAT WAVE WILL QUICKLY SLIDE TO THE SOUTHEAST...THEN NEXT WAVE AND ASSOCIATED COLD FRONT (FROM A LOW MOVING THROUGH NORTHERN ONTARIO) WILL MOVE SOUTHEAST THROUGH THE CWA LATE WEDNESDAY NIGHT AND THURSDAY. THERE ARE STILL SOME TIMING DIFFERENCES IN THE MODELS...WITH THEM SPEEDING IT UP SOME FROM PREVIOUS RUNS. THIS WILL LIKELY PUSH THE FRONT AND A BULK OF THE PRECIPITATION THROUGH THE AREA ON THURSDAY MORNING AND INTO EARLY THURSDAY AFTERNOON. WILL SHOW CHANCE POPS MOVING THROUGH THE AREA DURING THAT PERIOD...WITH THE HIGHEST NEAR THE LAKE MICHIGAN SHORELINE WITH THE ADDED HELP OF DIURNAL HEATING. WILL HAVE THUNDER CHANCES FOLLOW THE POPS...AS THERE ARE FAIRLY STEEP LAPSE RATES (7 C/KM OR HIGHER) ALONG AND AHEAD OF THE FRONT. IF THE FRONT MOVES THROUGH A LITTLE SLOWER...THERE WOULD BE ENOUGH SHEAR TO SUPPORT STRONGER THUNDERSTORMS OVER THE SOUTHEASTERN U.P. ON THURSDAY AFTERNOON. BEHIND THE COLD FRONT...THERE ARE SOME HINTS IN THE MODELS OF A VERY WEAK SHORTWAVE BRUSHING THE AREA ON THURSDAY NIGHT...OTHERWISE...HIGH PRESSURE FROM THE CANADIAN PRAIRIES WILL MOVE SOUTHEAST OVER THE UPPER GREAT LAKES REGION ON FRIDAY AND REMAIN INTO SATURDAY. THAT SHOULD LEAD TO A NICE COUPLE OF DAYS IN THE U.P. WITH HIGHS IN THE 70S TO AROUND 80 DEGREES WITH AFTERNOON LAKE BREEZES. THE HIGH WILL START TO SHIFT TO THE SOUTHEAST ON SATURDAY NIGHT AS THE UPPER RIDGE AXIS CROSSES THE UPPER GREAT LAKES REGION. BEHIND THAT UPPER RIDGE...ANOTHER TROUGH WILL MOVE THROUGH THE AREA FOR LATER SUNDAY AND INTO SUNDAY NIGHT AND WILL SPREAD CHANCE POPS EAST ACROSS THE AREA FOR THAT TIME FRAME. AT THIS TIME...MODELS ARE CONSISTENT ON IT QUICKLY SHIFTING EAST AND LEADING TO A MAINLY DRY MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 146 PM EDT MON AUG 10 2015 VFR CONDITIONS EXPECTED THROUGH TAF PERIOD AT KIWD AND KCMX. SCT-MID CLOUDS WILL AFFECT BOTH SITES AT TIMES...ESPECIALLY TONIGHT AS SHRA DISSIPATE WHILE MOVING OUT OF NORTHEAST MN AND NORTHERN ONTARIO. AT KSAW...VFR CONDITNONS SHOULD PREVAIL UNTIL LATE TONIGHT WHEN LOW CLOUDS CURRENTLY OVER NORTHERN ONTARIO DROP ACROSS LK SUPERIOR AND MOVE INTO NORTHERN UPR MICHIGAN ON NORTH WINDS. CIGS SHOULD SETTLE INTO LOW MVFR RANGE AROUND SUNRISE ON TUESDAY...WITH SOME POTENTIAL OF IFR CIGS THROUGH TUE MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 509 AM EDT MON AUG 10 2015 IN THE WAKE OF A COLD FRONT CROSSING THE UPPER LAKES...W TO NW WINDS WILL BEGIN TO INCREASE TODAY ACROSS LAKE SUPERIOR...THOUGH WINDS WILL REMAIN UNDER 20KT. ANY FOG OVER THE LAKE SHOULD GRADUALLY DISSIPATE. TONIGHT/TUE...PRES GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE TO 10-20KT OUT OF THE SW INTO THU AHEAD OF THE NEXT APPROACHING COLD FRONT. DEPENDING HOW MUCH THE PRES GRADIENT TIGHTENS...WILL NEED TO WATCH FOR THE POTENTIAL OF WINDS TO INCREASE FURTHER INTO THE 15-25KT RANGE...WITH PERHAPS GUSTS TO 30KT AT THE HIGHEST OBS PLATFORMS. WINDS WILL DIMINISH AFTER THE FRONT PASSES. EXPECT LIGHTER WINDS UNDER 15KT ON FRI AS HIGH PRES BUILDS INTO THE UPPER LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ249>251- 266-267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...JLA MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
147 PM EDT MON AUG 10 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 509 AM EDT MON AUG 10 2015 WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A RIDGE OVER THE ROCKIES WITH DOWNSTREAM TROF BEGINNING TO DEEPEN FROM HUDSON BAY S INTO THE GREAT LAKES. IN THE DEVELOPING NW FLOW INTO THE GREAT LAKES...THERE IS ONE SHORTWAVE OF NOTE UPSTREAM E OF LAKE WINNIPEG ALONG THE ONTARIO/MANITOBA BORDER. CLOSER TO HOME...SCT SHRA CONTINUE EARLY THIS MORNING OVER ROUGHLY THE E HALF UPPER MI...AHEAD OF COLD FRONT. WILL CONTINUE TO CARRY SCT SHRA OVER THE ERN FCST AREA THIS MORNING AHEAD OF SLOW MOVING COLD FRONT. MIGHT BE A FEW RUMBLES OF THUNDER. WHERE CLOUDS SCATTER OUT...EXPECT SOME FOG UNTIL MID MORNING... ESPECIALLY IN THOSE AREAS WHERE RAINFALL HAS OCCURRED OVER THE LAST 12HRS. THIS AFTN...UNDER NNW FLOW...LAKE BREEZE COMPONENTS TO WIND WILL LEAD TO AN AREA OF CONVERGENCE IN SCNTRL UPPER MI. WITH POTENTIAL OF 50-200J/KG OF MLCAPE PER GFS/RAP/HRRR...ISOLD SHRA/TSTM MAY DEVELOP (NAM LOOKS WAY TOO HIGH WITH MLCAPES OVER 1000J/KG). WITH MOST OF THE HIGH RES MODEL GUIDANCE SHOWING SOME CONVECTION IN THAT AREA...WILL INCLUDE SCHC TO LOW CHC POPS IN SCNTRL UPPER MI THIS AFTN. AHEAD OF THE LAKE BREEZE OFF LAKE SUPERIOR...MAY SEE A FEW SHRA/TSRA E TOWARD KISQ/KERY AS WELL. AS SHORTWAVE CURRENTLY E OF LAKE WINNIPEG DROPS SE...REACHING WRN LAKE SUPERIOR THIS EVENING...THERE SHOULD BE QUITE A BIT OF SHRA AND SOME TSTMS DEVELOPING NW OF LAKE SUPERIOR THIS AFTN. THIS CONVECTION WILL SPREAD OUT OVER NW LAKE SUPERIOR IN THE AFTN. NOT SURE HOW FAR THIS ACTIVITY WILL SPREAD BEFORE DISSIPATING OVER THE COOLER MARINE LAYER. HOWEVER...WITH WATER NOT AS COLD AS EARLIER IN THE SUMMER AND WITH SUPPORT FROM DECENT LOOKING SHORTWAVE...SOME OF THIS ACTIVITY CERTAINLY HAS THE POTENTIAL TO SURVIVE IN A WEAKENED STATE INTO NW UPPER MI LATE THIS AFTN/EARLY EVENING. ANY -SHRA THAT SURVIVE THE TRIP ACROSS THE LAKE INTO NW UPPER MI WILL DISSIPATE THIS EVENING AS SHORTWAVE QUICKLY MOVES E OF THE AREA. THIS WILL LEAD TO A QUIET OVERNIGHT. SINCE GFS AND ESPECIALLY NAM SUGGEST AN INCREASE IN LOW CLOUDS OCCURRING LATE IN THE NIGHT INTO TUE MORNING...CLOUD COVERAGE WAS TRENDED UP OVERNIGHT... ESPECIALLY ACROSS THE N WHERE UPSLOPE WIND SHOULD AID CLOUD DEVELOPMENT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 240 AM EDT MON AUG 10 2015 THE 500MB TROUGH SET UP ACROSS MUCH OF EASTERN CANADA AND THE EASTERN US. THE LAST SHORTWAVE OVER W LAKE SUPERIOR AT 12Z TUESDAY WILL EXPAND ACROSS E UPPER MI THROUGH THE AFTERNOON AND EVENING HOURS. WHILE THIS AND THE STEADY N-NNW WINDS WILL KEEP CLOUDS STUCK OVER THE E HALF...LINGERING PRECIP IS STILL UNKNOWN ESPECIALLY WITH PW VALUES DIMINISHING THROUGH FROM A MAX OF AROUND 1.25 EARLY IN THE DAY TO AROUND 1 IN BY MID AFTERNOON TUESDAY. THE SFC HIGH STRETCHING FROM HUDSON BAY DOWN THROUGH THE CENTRAL PLAINS TUESDAY MORNING WILL SETTLE ACROSS THE CWA BY 06Z WEDNESDAY. THE CANADIAN/ECMWF/AND GFS ARE ALL BRINGING IN ADDITIONAL PRECIP WEDNESDAY ASSOCIATED WITH A WARM FRONT EXTENDING FROM A LOW WAY UP IN N CENTRAL CANADA. THIS WILL COINCIDE WITH THE SFC RIDGE SHIFTING SLIGHTLY TO THE SE. THE NAM IS LESS IMPRESSIVE...AND HAS ONLY INCREASED CLOUD COVER. GIVEN THE OVERALL LIMITED MOISTURE...WILL KEEP POPS TO A MINIMUM. THE SFC LOW WILL SHIFT E AND STRETCH FROM N CANADA THROUGH HUDSON BAY BY THURSDAY AFTERNOON...WITH THE COLD FRONT SET UP ACROSS ONTARIO...NW LAKE SUPERIOR AND CENTRAL MN. LOOK FOR A BETTER CHANCE OF SHOWERS THURSDAY AS THE FRONT ROLLS THROUGH...SHIFTING SE OF THE CWA BY MID MORNING FRIDAY. INCREASED WIND GUSTS A BIT MORE DUE TO INCREASED MIXING AROUND THE COLD FRONT. LOOK FOR HIGH PRESSURE TO QUICKLY BUILD IN FRIDAY...AND REMAIN THROUGH SATURDAY...WITH DRY WEATHER FIGURED. WAA WILL BEGIN AGAIN SATURDAY NIGHT AS THE LARGE AREA OF HIGH PRESSURE SHIFTS E. THE ECMWF IS QUICKER TO HAVE THE HIGH SHIFT E IN ADVANCE OF THE NEXT CANADIAN LOW AND ASSOCIATED COLD FRONT FOR SUNDAY-MONDAY. WILL GO WITH A GENERAL BLEND FOR THE WEEKEND ON THE TIMING. WHILE TS MAY BE MORE ALIGNED NEAR THE COLD FRONT...WILL GO WITH GENERAL SHOWERS AND THUNDERSTORMS AT THIS POINT...WHICH WILL NEED TO BE FINE TUNED AS THE TIME NEARS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 146 PM EDT MON AUG 10 2015 VFR CONDITIONS EXPECTED THROUGH TAF PERIOD AT KIWD AND KCMX. SCT-MID CLOUDS WILL AFFECT BOTH SITES AT TIMES...ESPECIALLY TONIGHT AS SHRA DISSIPATE WHILE MOVING OUT OF NORTHEAST MN AND NORTHERN ONTARIO. AT KSAW...VFR CONDITNONS SHOULD PREVAIL UNTIL LATE TONIGHT WHEN LOW CLOUDS CURRENTLY OVER NORTHERN ONTARIO DROP ACROSS LK SUPERIOR AND MOVE INTO NORTHERN UPR MICHIGAN ON NORTH WINDS. CIGS SHOULD SETTLE INTO LOW MVFR RANGE AROUND SUNRISE ON TUESDAY...WITH SOME POTENTIAL OF IFR CIGS THROUGH TUE MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 509 AM EDT MON AUG 10 2015 IN THE WAKE OF A COLD FRONT CROSSING THE UPPER LAKES...W TO NW WINDS WILL BEGIN TO INCREASE TODAY ACROSS LAKE SUPERIOR...THOUGH WINDS WILL REMAIN UNDER 20KT. ANY FOG OVER THE LAKE SHOULD GRADUALLY DISSIPATE. TONIGHT/TUE...PRES GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE TO 10-20KT OUT OF THE SW INTO THU AHEAD OF THE NEXT APPROACHING COLD FRONT. DEPENDING HOW MUCH THE PRES GRADIENT TIGHTENS...WILL NEED TO WATCH FOR THE POTENTIAL OF WINDS TO INCREASE FURTHER INTO THE 15-25KT RANGE...WITH PERHAPS GUSTS TO 30KT AT THE HIGHEST OBS PLATFORMS. WINDS WILL DIMINISH AFTER THE FRONT PASSES. EXPECT LIGHTER WINDS UNDER 15KT ON FRI AS HIGH PRES BUILDS INTO THE UPPER LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ249>251- 266-267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...JLA MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DULUTH MN
1252 PM CDT MON AUG 10 2015 .UPDATE... ISSUED AT 1037 AM CDT MON AUG 10 2015 UPDATED THE FORECAST THROUGH AROUND MIDNIGHT...FOCUSING ON PCPN CHANCES AND CLOUD COVER. LATEST MODEL SOUNDINGS AND HRRR RUNS SUGGEST THERE WILL BE SCT/BKN CUMULUS ACROSS MUCH OF THE FORECAST AREA BY EARLY THIS AFTERNOON...SO EXPANDED CLOUD COVER. THE LATEST NAM12/SREF/GFS/HRRR INDICATED THE NORTHERN AND SE FORECAST AREA COULD GET ISOLATED/SCATTERED SHOWERS AND STORMS THIS AFTERNOON AND EARLY EVENING...SO INCREASED AND EXPANDED COVERAGE OF PCPN CHANCES. THERE MAY BE A THREAT FOR ISOLATED STRONG STORMS IN THE COOK COUNTY AREA OF THE ARROWHEAD THIS AFTERNOON AND EARLY EVENING. THE NAM12 AND GFS SOUNDINGS FOR THE HIGHER TERRAIN OF THE ARROWHEAD INDICATE MUCAPE COULD BUILD TO AROUND 1000 J/KG BY THE MIDDLE OF THE AFTERNOON...AND THERE WOULD BE ABOUT 30 TO 35 KNOTS OF DEEP LAYER WIND SHEAR. ALSO...FREEZING LEVELS WILL BE RELATIVELY LOW IN THE HIGHER TERRAIN...ABOUT 9000 FT. THEREFORE...WOULD NOT BE SURPRISED BY ISOLATED STORMS CAPABLE OF PRODUCING SMALL HAIL AND GUSTY WINDS. UPDATE ISSUED AT 612 AM CDT MON AUG 10 2015 PATCHY FOG WAS DOTTING THE LANDSCAPE...BUT SHOULD BURN OFF QUICKLY. STILL ANTICIPATING SHOWERS AND STORMS WITH THE SHORTWAVE TROF SET TO CLIP THE ARROWHEAD TODAY. LOWERED THE POPS IN NW WI A BIT AS THE TROF STAYS A BIT FURTHER EAST. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 309 AM CDT MON AUG 10 2015 A SFC LOW CENTER WAS MOVING THROUGH EASTERN LAKE SUPERIOR AT 07Z WITH ITS ASSOCIATED FRONTAL BOUNDARY MOVING THROUGH NW WI. AREAS OF FOG HAD FORMED ONCE AGAIN ACROSS MUCH OF THE REGION. EXPECT THE FOG TO LINGER UNTIL 14Z. AS THE FRONT EXITS NW WI...HIGH PRESSURE BUILDS ACROSS THE AREA. HOWEVER...AN UPPER LEVEL SHORTWAVE TROF WILL REACH THE INTERNATIONAL BORDER BY 18Z AND PROCEED ACROSS THE ARROWHEAD AND OVER LAKE SUPERIOR. SCATTERED SHOWERS AND THUNDERSTORMS WILL BEGIN TO AFFECT THE ARROWHEAD WWD TO NEAR CDD AT 15Z. STORMS WILL PERCOLATE OVER THE ARROWHEAD THROUGH THE AFTERNOON WITH SOME STORM DEVELOPMENT IN NW WI IN THE AFTERNOON. THE SHORTWAVE TROF REACHES NORTHERN LOWER MICHIGAN BY 06Z TUESDAY. ONE MORE IMPULSE WILL CLIP THE ARROWHEAD BEHIND THE TROF AND RESULT IN SOME ISOLD SHOWERS FROM CKC TO GRAND PORTAGE. THIS ACTIVITY WILL DIMINISH BY 03Z AS FORCING MOVES EAST AND SFC RIDGING COVERS THE AREA. THE SFC RIDGING PERSISTS THROUGH TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 309 AM CDT MON AUG 10 2015 WARMER MID-WEEK WITH HIGHS IN THE LOW TO MID 80S ACROSS THE REGION...THEN NOT AS HOT BUT STILL ABOVE NORMAL THROUGH SATURDAY WITH HIGHS IN THE UPPER 70S TO LOW 80S. TWO MAIN PERIODS OF POSSIBLE PRECIPITATION...ONE ON WEDNESDAY NIGHT INTO THURSDAY AS A COLD FRONT SWEEPS THROUGH FROM NORTHWEST TO SOUTHEAST...THEN AGAIN SATURDAY NIGHT INTO SUNDAY AS ANOTHER COLD FRONT MOVES THROUGH. SOME UNCERTAINTY EXISTS WITH THE TIMING OF THE LATE WEEKEND SYSTEM...BUT IN GENERAL HAVE AN AVERAGE LEVEL OF CONFIDENCE FOR THE FORECAST. ON THE SYNOPTIC SCALE A UPPER LEVEL RIDGE CENTERED OVER THE HIGH PLAINS WILL GRADUALLY DRIFT WESTWARD TOWARDS THE FOUR CORNERS THROUGH THE REST OF THE WORK WEEK...LEADING TO NORTHWEST FLOW ALOFT LOCALLY. AHEAD OF A COLD FRONT/MID LEVEL DISTURBANCE SOUTHWESTERLY WINDS COULD BECOME BREEZY WITH STRONG WARM AIR ADVECTION LEADING TO PROBABLY THE WARMEST DAY OF THE FORECAST PERIOD. THERE IS A WEAK MID- LEVEL IMPULSES IN THE NORTHWESTERLY FLOW WITH AN ASSOCIATED SFC LOW THAT MOVES ACROSS NORTHWEST MINNESOTA INTO NORTHERN WISCONSIN LATE WEDNESDAY INTO THURSDAY. THIS WILL BE SUPPORTED BY A 60-80 KT UPPER LEVEL JET STREAK OVER THE UPPER MISSISSIPPI VALLEY...POSSIBLY PEAKING UP TO 100 KTS IN STRENGTH OVER CENTRAL MINNESOTA. MODEL SOUNDINGS DEPICT MODEST MID-LEVEL LAPSE RATES TO SUPPORT THUNDERSTORMS...AND THE STRONG WINDS ALOFT WILL RESULT IN 35-45 KTS DEEP LAYER SHEAR SUPPORTIVE OF POSSIBLY A FEW STRONG STORMS OVERNIGHT INTO THURSDAY. COVERAGE OF STORMS MAY BE LIMITED GIVEN ELEVATED NATURE AND DEPENDENCE ON UPSTREAM CONVECTION EVOLUTION...BUT IN GENERAL THIS PERIOD LOOKS GOOD FOR ISOLATED/SCATTERED STORMS. FRIDAY/SATURDAY A HIGH PRESSURE OVER SOUTHERN SASKATCHEWAN/MANITOBA DRIFTS INTO THE NORTHERN PLAINS THEN EAST ACROSS THE UPPER GREAT LAKES RESULTING IN SUNNY SKIES AND SEASONABLE TO JUST ABOVE NORMAL TEMPERATURES...UPPER 70S TO MID 80S. LATE SATURDAY INTO SUNDAY AN UPPER LOW ENTERING BRITISH COLUMBIA WILL ABSORB THE ENERGY FROM AN UPPER LOW OFF THE COAST OF THE PACIFIC NORTHWEST...DEEPENING INTO AN UPPER LOW/TROUGH AS IT CROSSES THE CANADIAN PRAIRIE. A SECONDARY SFC LOW/LEE TROUGH WILL DEVELOP OVER THE NORTHERN PLAINS ON SATURDAY ALONG A COLD FRONT EXTENDING FROM NEAR THE MAIN SFC LOW IN SOUTHERN CANADA INTO THE CENTRAL PLAINS. GUIDANCE IS IN FAIRLY REMARKABLE AGREEMENT FOR THIS TIME RANGE...WITH ECMWF/GFS/GEM DEPICTING A STRONG COLD FRONT IN THE EASTERN DAKOTAS/FAR WESTERN MINNESOTA AROUND 00Z SUNDAY /SAT NIGHT/ PROGRESSING EASTWARD...THOUGH FROM THERE MODEL SOLUTIONS DIVERGE. PRECIP CHANCES LOOK FAIRLY HIGH REGARDLESS OF SPECIFICS. MOISTURE CONTENT WITH THIS SYSTEM MAY BE ON THE HIGH SIDE GIVEN THE PACIFIC INFLUENCES. COOLER TEMPERATURES EXPECTED IN WAKE OF THIS FRONT WITH HIGHS NEAR OR SLIGHTLY BELOW SEASONABLE...IN THE LOW TO MID 70S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1238 PM CDT MON AUG 10 2015 VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS WITH A SCT-BKN CLOUD DECK AROUND 040-050 THIS AFTERNOON AND VCSH AROUND INL AND HIB. CLOUDS SCOUR OUT THIS EVENING AND TONIGHT. MAY SEE SOME PATCHY FOG LATE TONIGHT AND TUE MORNING. NW WINDS WILL GUST 10 TO 15 KTS TODAY AND BECOME LIGHT FROM THE NW TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... DLH 77 57 75 59 / 20 10 0 10 INL 75 52 77 56 / 20 10 0 10 BRD 79 55 80 56 / 0 0 0 0 HYR 77 55 76 53 / 20 20 0 10 ASX 76 57 73 54 / 20 20 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. LS...NONE. && $$ UPDATE...GROCHOCINSKI SHORT TERM...GSF LONG TERM...JJM AVIATION...TENTINGER
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
113 PM CDT MON AUG 10 2015 .UPDATE: ISSUED AT 1255 PM CDT MON AUG 10 2015 NO MAJOR CHANGES MADE. UPDATE WAS MAINLY FOR FINE TUNING POPS AND SKY COVER FOR THE AFTN. BAND OF SHRAS AND ISLD TSTMS DVLPD LATE THIS MRNG ALONG THE FRONT. THIS ACTIVITY WILL CONTINUE TO PERCOLATE THRU THE AFTN AS IT SLOWLY DRIFTS SE. NE MO AND W CNTRL IL MAY GET CLIPPED LATE THIS AFTN WITH THE TAIL END OF PRECIP ASSOC WITH A WEAK SHORT WAVE TO OUR NE. NUDGED HIGH TEMPS UP A A COUPLE DEGREES ACROSS NTHRN ZONES WHERE THERE ARE LESS CLOUDS AND DOWN A COUPLE DEGREES ACROSS STHRN ZONES WHERE CONVECTIVE DEBRIS CLOUDS ARE LINGERING. MILLER && .SHORT TERM: (THROUGH LATE THIS AFTERNOON) ISSUED AT 332 AM CDT MON AUG 10 2015 SHORT RANGE GUIDANCE SEEMS TO BE IN GOOD AGREEMENT WITH CURRENT RADAR TRENDS IN CONTINUING TO PUSH THE BAND OF CONVECTION SOUTH OF OUR CWFA BY 12Z. UPSTREAM DEVELOPMENT OVER SOUTHWEST MISSOURI LOOKS LIKE IT SHOULD STAY OUT OF OUR AREA...BUT WE MAY STILL GET CLIPPED SO HAVE KEPT MID-HIGH CHANCE POPS GOING PAST 12Z ACROSS SOUTHERN ZONES. FURTHER NORTH, SHORT RANGE GUIDANCE HAS CONSISTENTLY BEEN WEAKENING THE CONVECTION NOW MOVING INTO NORTHWEST MISSOURI OUT OF IOWA, AND CURRENT RADAR TRENDS SUPPORT THIS AS WELL. THAT BEING SAID, ISOLATED TO WIDELY SCATTERED STORMS WILL CONTINUE TO BE POSSIBLE ACROSS THROUGH THE MORNING FROM I-70 NORTHWARD. THE ACTUAL SYNOPTIC COLD FRONT IS DIFFICULT TO FIND AT THIS TIME, BUT LOOKS LIKE IT SHOULD PUSH THROUGH THE AREA FROM MID MORNING THROUGH THE AFTERNOON. RAP HAS THE 850MB FLOW TURNING SHARPLY TO THE NORTH- NORTHWEST WITH DECENT COLD ADVECTION (FOR AUGUST) BEHIND IT. SHOULD STILL BE ENOUGH INSTABILITY TO CONTINUE A CHANCE OF THUNDERSTORMS THROUGH THE AFTERNOON INTO EARLY EVENING. STUCK PRETTY CLOSE TO GUIDANCE FOR TEMPERATURES TODAY...THOUGH HIGHS WILL BE DIFFICULT TO PIN DOWN DUE TO AFTERNOON CONVECTION. CARNEY .LONG TERM: (TONIGHT THROUGH SUNDAY) ISSUED AT 345 AM CDT MON AUG 10 2015 EXPECT A FEW SHOWERS OR THUNDERSTORMS TO LINGER INTO EARLY THIS EVENING, BUT SHOULD BE GONE BEFORE MIDNIGHT. DRIER AIR IS FORECAST TO BUILD ACROSS THE AREA BEHIND THE FRONT TONIGHT AND TUESDAY...AND LAST AT LEAST THROUGH THE END OF THE WEEK WITH DEWPOINT TEMPERATURES DROPPING INTO THE 60S. A HIGH AMPLITUDE UPPER LEVEL PATTERN LOCKS THE DRY LOW LEVEL RIDGE OVER THE MISSISSIPPI VALLEY, SO PRECIPITATION CHANCES ARE VIRTUALLY NIL. THIS SHOULD MAKE FOR RELATIVELY COMFORTABLE WEATHER FOR WHAT ARE TYPICALLY THE DOG-DAYS OF SUMMER WITH HIGHS NEAR OR A FEW DEGREES BELOW NORMAL IN THE MID TO UPPER 80S AND LOWS WELL BELOW NORMAL IN THE 60S. CARNEY && .AVIATION: (FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1255 PM CDT MON AUG 10 2015 PATCHES OF MVFR STRATUS CONTINUE TO DOT THE REGION EARLY THIS AFTN. CLOUD HEIGHTS SHOULD CLIMB THRU THE AFTN WITH MVFR CIGS BCMNG AROUND 21Z. A BAND OF SHRAS AND ISLD TSTMS DVLPD LATE THIS AFTN ALONG A COLD FRONT. THIS ACTIVITY WILL CONTINUE TO PERCOLATE THRU THE AFTN WHILE SLOWLY DRIFTING SE. VSBYS MAY BRIEFLY DIP TO IFR UNDER THE HEAVIEST CORES. ANOTHER AREA OF PRECIP ASSOC WITH AN UPPER LVL DISTURBANCE NEAR THE STHRN END OF LK MI MAY CLIP KUIN LATE THIS AFTN BUT CHANCES AREA MINIMAL ATTM. PRECIP SHOULD DSSPT AND SKIES SLOWLY CLEAR AFTER SUNSET. SPECIFICS FOR KSTL: BROKEN LINE OF SHRAS AND ISLD TSTMS HAS DVLPD JUST NORTH OF THE MO RVR FROM NEAR KC TO STL. VSBYS MAY DROP TO IFR UNDER THE STRONGEST CORES BUT WILL BE BRIEF. THIS ACTIVITY WILL DRIFT SE THRU THE AFTN. CONVECTIVE ELEMENTS WILL BE TRANSIENT THE AFTN AND WILL UNDOUBTABLY HAVE TO UPDATE THE TAF AS THE LINE APPROACHES THE TERMINAL. SPOTTY MVFR CIGS WILL CONTINUE TO RAISE THRU THE AFN BECMNG VFR IN A FEW HRS. PRECIP AND CLOUDS WILL SLOWLY DIMINISH AFTER SUNSET WITH VFR CONDITIONS EXPECTED FOR THE REST OF THE FCST PRD. MILLER && .PRELIMINARY POINT TEMPS/POPS: SAINT LOUIS 88 72 86 68 / 30 20 5 0 QUINCY 85 64 84 62 / 20 20 5 0 COLUMBIA 87 67 85 63 / 30 10 5 0 JEFFERSON CITY 87 68 86 63 / 30 10 5 0 SALEM 84 70 84 63 / 30 20 10 0 FARMINGTON 84 69 84 61 / 30 20 10 0 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ELKO NV
345 PM PDT MON AUG 10 2015 .SYNOPSIS...POCKETS OF MOISTURE AND INSTABILITY WILL FUEL THUNDERSTORM ACTIVITY. CONVECTION IS EXPECTED THIS AFTERNOON AND EVENING OVER PORTIONS OF NORTHEASTERN NEVADA. TEMPERATURES WILL BE NEAR NORMAL. EXPECTING ANOTHER MONSOON SURGE THIS WEEK. && .SHORT TERM...TODAY THROUGH WEDNESDAY. KLRX HAS BEEN ACTIVE OVER ELKO COUNTY THIS AFTERNOON. THE JET IS DIRECTLY OVER THE LKN CWA...PROVIDING SUFFICIENT UPWARD VERTICAL VELOCITY OVER NE NV. QPF-WISE...THE HRRR IS OVER DONE SOUTH OF I-80...THE NAM IS OVER DONE IN LANDER AND EUREKA COUNTIES AND THE GFS IS UNDER DONE FOR ALL THE EASTERN ZONES THIS AFTERNOON AND EVENING. THE MODELS CONTINUE TO STRUGGLE WITH THE ENERGY BEING EJECTED FROM THE PACIFIC LOW AND THE PLACEMENT OF THE MOISTURE. TOMORROW...EXPECTING THE MONSOON SURGE TO MOVE ACROSS ARIZONA AND INTO THE EASTERN GREAT BASIN THIS FORECAST PERIOD. THE NAM HAS THE FETCH OF MOISTURE BISECTING CENTRAL NV AND THE GFS KEEPS IT RESTRICTED TO THE EASTERN GREAT BASIN. THE NCEP RMOP IS ALSO DEPICTING MODELING ISSUES AS EARLY AS 24 HRS. THE NAEFS ANOMALIES ARE PINGING INTO A STRONG IVT...WITH A 30 YEAR RETURN INTERVAL FOR WEDNESDAY. IF THAT VERIFIES...IT WOULD TRANSLATE INTO POTENTIAL FLOODING ISSUES NEAR THE BORDER OF UTAH...BUT THAT SHOULD BE TEMPERED WITH THE VAGARIES OF THE MODELS PERFORMANCES THE PAST SEVERAL DAYS. NO SHORTAGE OF UNCERTAINTY THIS PERIOD...BUT ALSO SOME POTENTIALLY INTERESTING WEATHER ON THE HORIZON. STAY TUNED FOR MORE DETAILS. .LONG TERM...WEDNESDAY NIGHT THROUGH NEXT MONDAY. THE MODELS HAVE DISAGREED ON TIMING...STRENGTH...POSITION AND JUST ABOUT EVERYTHING ELSE FOR A WEEK...COMING A LITTLE CLOSER EACH DAY. TODAY...THEY SEEM TO BE IN ALMOST PERFECT AGREEMENT. MODERATELY SERIOUS DISAGREEMENT DOES NOT APPEAR UNTIL SUNDAY NIGHT. MAJOR MODELS HAVE A SLUG OF QUASI-MONSOON MOISTURE EXITING THE REGION WEDNESDAY NIGHT WITH SOME LEFTOVER CONVECTION IN THE EASTERN BORDERLANDS. THIS SLIDES ON EAST AND A DRY SOUTHWEST FLOW SETS UP FOR THE REMAINDER. THERE WILL NO DOUBT BE AN ISOLATED DRY STORM NOW AND THEN WITH HEAT AND SOME ELEVATED MOISTURE AND HUMIDITY. BUT HAVE KEPT POPS LOW ENOUGH AFTER THURSDAY TO ESSENTIALLY ELIMINATE MENTION OF SENSIBLE WEATHER. TEMPS REMAIN NEAR TO SLIGHTLY ABOVE NORMAL. WINDS WILL KICK UP THURSDAY AND WITH LOW RH`S COULD SEE SOME FIRE WEATHER PROBLEMS. && .AVIATION...VFR CONDITIONS ARE EXPECTED AT KWMC KEKO KELY AND KTPH THROUGH TUESDAY AFTERNOON. ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE THROUGH EASTERN NEVADA THIS AFTERNOON AND EARLY EVENING...AFFECTING MAINLY KEKO AND DISTANTLY KELY. THE USUAL GUSTY WINDS AROUND STORMS...SHOWERS...AND VIRGA. DIMINISH OVERNIGHT BUT FIRE UP AGAIN TUESDAY AFTERNOON. && .FIRE WEATHER...MULTIPLE THUNDERSTORMS HAVE POPPED UP OVER 469 AND 470 TODAY. EXPECTING ACTIVITY TO TAPER OFF THIS EVENING. THE NEXT CONVECTIVE PUSH WILL BE MONSOONAL IN NATURE...ALTHOUGH WETTING RAINS WILL BE PROBABLE...ALTHOUGH NOT NECESSARILY COINCIDENT WITH THE LIGHTNING STRIKES. && .LKN WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 97/98/98/97
AREA FORECAST DISCUSSION...COR
NWS WILMINGTON NC
304 PM EDT MON AUG 10 2015 .SYNOPSIS... RAIN CHANCES WILL INCREASE TUESDAY AND EXTEND INTO WEDNESDAY AS A COLD FRONT MAKES ITS WAY INTO THE AREA. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT LATE WEDNESDAY...OFFERING SEASONABLE AND MAINLY DRY CONDITIONS INTO NEXT WEEKEND. A CHANCE OF RAIN MAY RETURN EARLY NEXT WEEK AS HIGH PRESSURE MOVES OFFSHORE AND DIRECTS MOISTURE ONSHORE. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM MONDAY...CLOUD COVER HAS BEEN PRETTY EXTENSIVE ACROSS THE INLAND HALF OF THE CWA...BUT COASTAL SECTIONS HAVE ONCE AGAIN EXPERIENCED A GREAT EARLY-AUGUST DAY. MOISTURE WILL CONTINUE TO INCREASE IN BOTH THE MID-LEVELS AND AT THE SURFACE...FINALLY OVERCOMING THE VERY DRY AIR IN PLACE AS THE SURFACE RIDGE OVERHEAD SHIFTS OFFSHORE. SHOWERS THAT HAD DEVELOPED WEST OF THE CWA HAVE ERODED AS EXPECTED THANKS TO ENCOUNTERING DRY AIR...AND HIGH RES GUIDANCE INCLUDING THE HRRR AND NSSL WRF BOTH KEEP THE CWA DRY THROUGH TONIGHT. HAVE REMOVED MENTION OF POP FROM EVEN IN THE FAR INLAND ZONES THROUGH DARK TO ACCOUNT FOR TRENDS IN SATELLITE AND RADAR. TONIGHT...COLUMN SATURATION WILL CONTINUE TO INCREASE WITH PWATS RISING TOWARDS 2 INCHES BY TUESDAY MORNING. COLD FRONT APPROACHING FROM THE WEST WILL BE NEAR THE CWA BY MORNING...WITH SHOWERS AND THUNDERSTORMS INCREASING AHEAD OF IT. FORECAST PROFILES SUGGEST ENOUGH SATURATION INLAND THAT POP HAS BEEN RAMPED UP TO HIGH CHC FROM I-95 WESTWARD BY 8AM TUESDAY...WITH JUST SCHC ALONG THE COAST...BUT MOST OF THE PRECIP WILL HOLD OFF UNTIL AFTER THIS PERIOD. INCREASING CLOUD COVER AND CONTINUED LIGHT SOUTHERLY WINDS WILL KEEP MINS ELEVATED TO ABOVE SEASONABLE NORMS TONIGHT. THE MAV AND MET ARE IN GOOD AGREEMENT...AND HAVE FORECAST MORE CLOSELY TO THE SLIGHTLY WARMER MAV NUMBERS. EXPECT LOWS IN THE 72-75 DEGREE RANGE THROUGHOUT THE AREA. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...THE PRIME WEATHER CAPTION FOR TUE/WED IS RAIN AS AN APPROACHING FRONTAL SYSTEM WITH RELATIVELY HIGH AMOUNTS OF INGESTED PRECIPITABLE WATER...CROSSES THE APPALACHIAN MOUNTAINS EARLY TUESDAY AND MOVES TO THE COAST TUESDAY NIGHT. IT APPEARS A WEAK WAVE OF LOW PRESSURE MOVING NNE ALONG THE FRONT MAY SUSTAIN ISOLATED COASTAL SHOWERS SLIGHTLY BEHIND THE DECAYING FRONTAL SYSTEM ON WEDNESDAY. BEST FIT AND CONSENSUS QPF DEPICTIONS OF STORM/SYSTEM TOTAL POINTS GENERALLY TO 0.50-0.75 INCHES OF RAIN TUE/WED AND HIGHEST ALONG AREAS IN PROXIMITY TO THE COAST. A TREND OF DRYING WILL PREVAIL ON WEDNESDAY ESPECIALLY INLAND...IN THE FACE OF ISOLATED COASTAL SHOWERS. POST-FRONTAL DOWNSLOPE WIND FLOW WEDNESDAY WITH LITTLE COLD AIR ADVECTION WILL LIKELY RESULT IN A SEASONABLY WARM DAY WEDNESDAY ALTHOUGH WE WILL OBSERVE SEVERAL DEGREES OF DEWPOINT DROPS THROUGH WEDNESDAY...TAKING A SLIGHT EDGE OFF THE HUMIDITY LEVELS. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...MID LEVEL TROUGHING WILL PERSIST ACROSS THE EAST/SOUTHEAST THROUGH SATURDAY WITH MORE OF A ZONAL PATTERN DEVELOPING THEREAFTER. GENERALLY QUIET WEATHER IS EXPECTED AS HIGH PRESSURE MOVES FROM THE MIDWEST TO THE APPALACHIANS THROUGH THE PERIOD. THE HIGH WILL WEAKEN WITH THE MID LEVEL TROUGH THUS LEAVING A WEAK PRESSURE PATTERN BOTH AT THE SURFACE AND ALOFT. HAVE CONTINUED THE SLIGHT CHANCE POPS WHICH ARE MOSTLY CONFINED TO THE COASTAL AND OFFSHORE ZONES. THE TEMPERATURE CURVE FOLLOWS THE SAME PROGRESSION WITH COOL READINGS EARLY ON...FRIDAY SHOULD BE THE COOLEST WITH 850MB TEMPERATURES NEAR 15 DEGREES C. THERMAL PROFILES SLOWLY MODIFY FROM THAT POINT ON. READINGS MAY ECLIPSE CLIMATOLOGY JUST BY A DEGREE OR TWO BY THE END OF THE PERIOD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...A BIT TRICKY WITH RESPECT TO PRECIP THIS AFTERNOON. CONVECTION ONGOING JUST WEST OF THE REGION AND THE MODELS ARE SIMILAR IN BRINGING THE CONVECTION TO THE I-95 CORRIDOR...BUT MOISTURE IS LIMITED AND HAVE REMOVED ANY MENTION OF SHOWERS DURING THE DAYLIGHT HOURS. TONIGHT...ISOLATED CONVECTION POSSIBLE OVER THE WESTERN THIRD OF THE REGION...WITH MID CLOUD CEILINGS DUE TO CONVECTIVE DEBRIS. TUESDAY...SHOWERS ON THE INCREASE AS YET ANOTHER COLD FRONT APPROACHES. CONVECTION COULD BECOME NUMEROUS AFTER THE END OF THE FORECAST PERIOD WITH FRONTAL LIFT AND INSTABILITY. EXTENDED OUTLOOK...SCATTERED SHOWERS AND STORMS TUESDAY NIGHT WITH INTERMITTENT MVFR/IFR CONDITIONS. BECOMING VFR WEDNESDAY WITH ISOLATED MORNING CONVECTION. VFR THURSDAY THROUGH SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM MONDAY...WEAK RIDGE OF HIGH PRESSURE WILL SLOWLY SHIFT OFFSHORE TONIGHT...SO ALTHOUGH THE GRADIENT WILL REMAIN LIGHT KEEPING WIND SPEEDS TO 10 KTS OR LESS...DIRECTION WILL CONTINUE TO VEER THROUGH TONIGHT...FROM CURRENT ESE ALL THE WAY TO SSW LATE. CURRENT BUOY OBS SHOW A MIX OF 5 SEC AND 10 SEC WAVES...WITH THE 10 SEC WAVE DOMINANT DUE TO THE LIGHT WINDS...AND THESE WILL PERSIST THROUGH THE PERIOD MAINTAINING WAVE HEIGHTS OF 2-3 FT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...MAIN MARINE HEADLINE THIS PERIOD REMAINS APPROACH AND DECAY OF A COLD FRONTAL SYSTEM OVER THE COASTAL WATERS DURING THE DAY WEDNESDAY. THIS MAY BRING A BRIEF PERIOD OF N-NW WINDS WEDNESDAY...PRECEDED BY COASTAL RAINSHOWERS AND ISOLATED TSTMS TUESDAY NIGHT. A FEW TSTMS MAY IMPACT THE OUTER WATERS ON WEDNESDAY AS WELL SINCE THE FRONT MAY SLOWLY DISSIPATE THERE MID-WEEK. SEAS WILL BUILD TO 3-4 FT TUESDAY NIGHT AHEAD OF THE COLD FRONT IN 15-20 KT SW WINDS...POSSIBLY 5 FT VERY OUTER PORTION. SEAS SETTLING TO 2-3 FT WED AFTN AND EVENING AS WIND SPEEDS GO LIGHT. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 3 PM MONDAY...HIGH PRESSURE WILL MOVE FROM THE MIDWEST TO THE APPALACHIANS THROUGH THE PERIOD. THE HIGH WILL SLOWLY WEAKEN LEAVING A BENIGN PRESSURE PATTERN BY SATURDAY. FOR THURSDAY AND FRIDAY WINDS WONT BE OVERWHELMING AND EXPECT A EAST/NORTHEAST DIRECTION IN A RANGE OF 10-15 KNOTS...MOSTLY HOVERING IN THE LOWER END OF THE RANGE. SPEEDS DROP TO TEN KNOTS AND BELOW BY SATURDAY. SIGNIFICANT SEAS WILL BE 1-3 FEET WITH AN EQUAL MIX OF A SHORTER PERIOD WIND WAVE AND SWELL COMPONENT. && .EQUIPMENT... AS OF 130 PM MONDAY...POWER TO THE ILM ASOS HAS BEEN LOST DUE TO A POWER SURGE. A REPLACEMENT IS ON ORDER...BUT IT IS LIKELY THAT ILM ASOS WILL BE WITHOUT AUTOMATED OBSERVATIONS THROUGH TODAY AND PART OF TUESDAY. THE ILM TOWER SHOULD AMEND OBSERVATIONS UNTIL 11 PM TONIGHT...AND RESUME EARLY TUESDAY MORNING. OVERNIGHT OBS MAY WILL BE MISSING FOR ALL PARAMETERS. AMD NOT SKED HAS BEEN APPENDED TO THE ILM TAF AND WILL REMAIN AS SUCH UNTIL POWER IS RESTORED TO THE SITE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...MBB LONG TERM...SHK AVIATION...JDW/DL MARINE...JDW/MJC/SHK EQUIPMENT...JDW
AREA FORECAST DISCUSSION
NWS RALEIGH NC
252 PM EDT MON AUG 10 2015 .SYNOPSIS...A MOIST SOUTHWEST FLOW WILL HOLD OVER THE REGION THROUGH TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST TUESDAY... AND PUSH SOUTHEAST THROUGH THE AREA LATE TUESDAY THROUGH TUESDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST WEDNESDAY THROUGH FRIDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1020 AM MONDAY... CURRENT FORECAST IS IN GOOD SHAPE. MAIN CHANGES WERE TO EXPAND IN TIME AND AREA THE BAND OF PATCHY SHOWERS CURRENTLY TRACKING THROUGH THE CWA... DRIVEN BY WEAK MOIST ISENTROPIC UPGLIDE IN THE LOW LEVELS AND A WEAK MID LEVEL WAVE... AND TO DELAY AFTERNOON CONVECTION IN THE WEST. HIGH-PW AIR (1.8-2.0") PERSISTS OVER CENTRAL NC WITH CONSIDERABLE MID AND HIGH DEBRIS CLOUDINESS FROM UPSTREAM MCS ACTION OVERSPREADING THE AREA FROM THE NW... AND THIS SHOULD SOMEWHAT CURB THE POTENTIAL FOR INSTABILITY THIS AFTERNOON. EXTRAPOLATION WOULD FAVOR ANY MCVS GENERATED BY LAST NIGHT`S THE CONVECTIVE COMPLEXES ACROSS SRN KS/MO/IL INTO WRN KY/TN LIKELY TRACKING WELL TO OUR SW... AND THIS TREND IS INDICATED BY THE NSSL WRF AND NCAR ENSEMBLE NEIGHBORHOOD PROBABILITIES. THESE MODEL PACKAGES ALSO SUGGEST THAT THE CHANCE FOR DEEP CONVECTION EAST OF HIGHWAY 1 THIS AFTERNOON INTO TONIGHT IS QUITE LOW... AND THE HRRR ALSO DEPICTS LITTLE TO NO COVERAGE OVER ALL BUT THE FAR WRN CWA AFTERNOON THROUGH AT LEAST 23Z. AFTER SLOWLY TRENDING THE COVERAGE OF SHOWERS DOWN THIS MORNING INTO EARLY AFTERNOON AS THEY TREND EASTWARD WITH WANING UPGLIDE... HAVE REDUCED CONVECTION CHANCES TO SLIGHT OR NIL IN THE EAST THIS AFTERNOON... AND HAVE CUT BACK COVERAGE IN THE WRN CWA A BIT AS WELL. GIVEN THE GENERALLY MOSTLY CLOUDY SKIES TODAY... HAVE CUT A COUPLE OF DEGREES OFF HIGHS... NOW RANGING FROM 84 TO 90. -GIH EARLIER DISCUSSION AS OF 255 AM: LATEST SURFACE ANALYSIS SHOWS WEAK HIGH PRESSURE EXTENDING INTO EASTERN VA AND NC. MEANWHILE A WARM FRONT EXTENDING FROM NEAR NASHVILLE TN SOUTHEAST TO NEAR SAVANNAH GA WAS BEGINNING TO SLOWLY LIFT NORTHWARD...LIKELY LIFTING THROUGH CENTRAL NC THIS AFTERNOON AND EVENING. FURTHER ALOFT...A RATHER WEAK DIFFLUENT NORTHWEST FLOW ALOFT WAS EXPECTED TO STRENGTHEN AND GRADUALLY BACK AND BECOME SOUTHWESTERLY BY LATE TONIGHT AS AN UPPER TROUGH DROPS INTO THE GREAT LAKES REGION. REGIONAL RADAR IMAGERY SHOWS SCT SHOWERS SLOWLY DEVELOPING AND EXPANDING ACROSS THE YADKIN VALLEY AND THE WESTERN PIEDMONT OF VA/NC/SC. THIS PRECIPITATION APPEARS TO BE ASSOCIATED WITH SOME ISENTROPIC UPGLIDE NEAR THE 305K SURFACE ENHANCED BY A WEAK SHORT WAVE ALOFT AND REMNANTS OF AN UPSTREAM MCS. NWP GUIDANCE SUGGESTS THAT THESE SHOWERS MAY BECOME MORE NUMEROUS AS THEY MOVE INTO THE WESTERN PIEDMONT TOWARD DAYBREAK. THE PRECIPITATION SHOULD BEGIN TO DIMINISH LATE THIS MORNING BEFORE REACHING THE COASTAL PLAIN. MUCH OF THE DAY TODAY SHOULD FEATURE A FAIR AMOUNT OF CLOUDINESS BUT MAINLY DRY CONDITIONS ACROSS CENTRAL NC. WITH LITTLE FORCING FOR ASCENT AND WITH ONLY WEAK INSTABILITY PRESENT THIS AFTERNOON AND FAIRLY MEAGER MID LEVEL LAPSE RATES...CONVECTIVE COVERAGE SHOULD BE RATHER LIMITED. THE ENVIRONMENT FOR CONVECTION BECOMES A LITTLE BIT MORE FAVORABLE THIS EVENING AND OVERNIGHT ACROSS THE WESTERN PIEDMONT AND TRIAD AREA AS LARGER SCALE FORCING APPROACHES AND MID LEVEL LAPSE RATE ACCORDINGLY INCREASE. STILL...CONVECTION ALLOWING MODELS HAVE TRENDED NOTICEABLY LESS ACTIVE FOR THIS AFTERNOON AND TONIGHT WITH NOCTURNAL CONVECTION NOW APPEARING MORE FOCUSED ACROSS VA/WV. HIGHS TODAY WILL BE COMPLICATED BY THE AMOUNT OF SUNSHINE AND WITH A TREND TOWARD LESS PRECIPITATION AND PERHAPS THINNER CLOUDS HAVE ADJUSTED MAXES UP EVER-SO-SLIGHTLY...HIGHS SHOULD RANGE SHOULD RANGE FROM 84 TO 91. LOWS TONIGHT WILL BE MODERATED BY A GOOD DEAL OF CLOUD COVER...LOWS SHOULD RANGE BETWEEN 69 AND 74 DEGREES. -BLAES && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 320 AM MONDAY... A STRENGTHENING UPPER TROUGH WILL MOVE ACROSS THE GREAT LAKES AND NORTHEAST DURING THE PERIOD WITH THE MAIN TROUGH AXIS SHIFTING ACROSS CENTRAL NC TOWARD DAYBREAK WEDNESDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS THE APPALACHIANS TUESDAY AFTERNOON AND THROUGH CENTRAL NC TUESDAY NIGHT...REACHING THE COAST TOWARD WEDNESDAY MORNING. SCATTERED CONVECTION IS EXPECTED AHEAD OF THE FRONT TUESDAY MORNING AND EARLY AFTERNOON. AS NOTED IN THE PREVIOUS DISCUSSION...THIS MAY PLAY A ROLE IN SUBSEQUENT CONVECTION TUESDAY AFTERNOON AND EVENING. WITH THE UPPER TROUGH CONTAINING MULTIPLE VORTICITY CENTERS...EXPECT SHOWERS AND THUNDERSTORMS TO MOVE ACROSS CENTRAL NC IN MULTIPLE CLUSTER OR BANDS THROUGHOUT THE AFTERNOON AS OPPOSED TO ONE WELL ORGANIZED LINE. THE CLOUDS AND PRECIPITATION WITH THESE CLUSTERS SHOULD RETARD INSTABILITY A BIT. SPC HAS CENTRAL NC OUTLOOKED WITH A MARGINAL THREAT OF SEVERE STORMS WHICH SEEMS REASONABLE GIVEN THE STRONGER DEEP LAYER FLOW AND BULK SHEAR VALUES OF 20-25 KTS SUGGESTING SOME STORM ORGANIZATION POSSIBLE. CAPE VALUES SHOULD RANGE FROM WEAK TO LOW END MODERATE WITH MLCAPE VALUES CLIMBING TO THE 750-1250 J/KG RANGE. THIS ENVIRONMENT WOULD SUPPORT A MULTICELLULAR/LINE SEGMENT CONVECTIVE MODE WITH A FEW STRONG STORMS AND POSSIBLY A SEVERE THUNDERSTORMS WITH DAMAGING WINDS THE MOST LIKELY THREAT. WITH A LINGERING SHORT WAVE TROUGH LIKELY TO MOVE ACROSS CENTRAL NC LATE TUESDAY EVENING...ANOTHER ROUND OF STORMS IS POSSIBLE WITH THIS FEATURE AND THE ASSOCIATED COLD FRONT. THE FRONT SHOULD EXIT THE RAH CWA BETWEEN 06-12Z AND BRING THE PRECIPITATION TO AN END. HIGHS IN THE 86 TO 91 RANGE WITH LOWS TUESDAY NIGHT IN THE 65 TO 73 RANGE. -BLAES && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AS OF 250 PM MONDAY... THE MAIN FRONT WILL SHIFT OFFSHORE ON WEDNESDAY...WITH GENERAL UPPER LEVEL TROUGHINESS LINGERING OVER THE CAROLINAS THROUGH MONDAY. AT THE SURFACE...HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND REMAIN OVERHEAD THROUGH MONDAY. WITH THAT IN MIND...MOST OF THE EXTENDED PERIOD WILL REMAIN DRY...WITH JUST A SLIGHT CHANCE FOR SHOWERS OVER THE WESTERN HALF OF THE STATE OVER THE WEEKEND. TEMPERATURES DURING THE PERIOD WILL FEATURE HIGHS IN THE MID 80S TO AROUND 90 DEGREES WITH OVERNIGHT LOWS GENERALLY IN THE MID 60S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 145 PM MONDAY... AVIATION CONDITIONS WILL BE SUB-VFR FOR THE MAJORITY OF THE NEXT 24 HOURS AT INT/GSO... HOWEVER AT RDU/FAY/RWI... THE SUB-VFR CONDITIONS WILL BE MORE SPORADIC WITH VFR DOMINATING AT LEAST THROUGH THIS EVENING. A MOIST SOUTHWESTERLY SURFACE FLOW INTO NC AHEAD OF AN APPROACHING COLD FRONT... COMBINED WITH LEFTOVER CLOUD COVER FROM STORM COMPLEXES TO THE WEST AND NORTHWEST OF NC... WILL KEEP MOSTLY CLOUDY SKIES AT ALL CENTRAL NC TERMINALS THROUGH TUE. CURRENT MVFR CIGS AT INT/GSO ARE EXPECTED TO LIFT BRIEFLY TO MAINLY VFR AFTER 21- 22Z TODAY... BUT THEN DROP BACK DOWN TO VFR AND POTENTIALLY IFR STARTING MID EVENING WITH NUMEROUS SHOWERS AND A FEW STORMS MOVING IN MAINLY AFTER 01Z... LASTING WELL INTO THE OVERNIGHT HOURS WITH PERIODIC MVFR VSBYS. MVFR CIGS AND PATCHY SHOWERS ARE LIKELY TO HOLD AT INT/GSO THROUGH THE END OF THE TAF VALID PERIOD... WITH PATCHY SHOWERS GIVING WAY TO MORE ORGANIZED THUNDERSTORMS TOWARD THE VERY END OF THE TAF VALID PERIOD (18Z TUE). RDU/FAY/RWI COULD SEE A PERIOD OF MVFR CIGS/VSBYS THROUGH THIS EVENING... BUT THE PROBABILITIES ARE LOW (HIGHER AT RDU THAN AT FAY/RWI BUT STILL LOW). AFTER 04Z... PATCHY SHOWERS ARE EXPECTED TO SHIFT EASTWARD NEARING THESE TAF SITES... AND THEY MAY GENERATE A PERIOD OF MVFR OR BRIEFLY IFR CIGS AND/OR MVFR VSBYS. SIMILAR TO INT/GSO... THE PATCHY MORNING SHOWERS MAY GIVE WAY TO SCATTERED STORMS IN THE AFTERNOON. LOOKING BEYOND 18Z TUE... SUB-VFR AND RAINY/STORMY CONDITIONS WILL DOMINATE AT ALL SITES THROUGH MUCH OF TUE AFTERNOON AND EVENING... WITH WINDS HOLDING FROM THE SW AT 9-15 KTS. AS THE FRONT PUSHES SE THROUGH THE AREA WITH HIGH PRESSURE BUILDING IN... WE`LL SEE A NW-TO- SE CLEARING TREND TO VFR CONDITIONS... WHICH WILL LAST INTO SAT WITH LARGELY DRY WEATHER. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BLAES SHORT TERM...BLAES LONG TERM...RAH AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
145 PM EDT MON AUG 10 2015 .SYNOPSIS...A MOIST SOUTHWEST FLOW WILL HOLD OVER THE REGION THROUGH TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST TUESDAY... AND PUSH SOUTHEAST THROUGH THE AREA LATE TUESDAY THROUGH TUESDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST WEDNESDAY THROUGH FRIDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1020 AM MONDAY... CURRENT FORECAST IS IN GOOD SHAPE. MAIN CHANGES WERE TO EXPAND IN TIME AND AREA THE BAND OF PATCHY SHOWERS CURRENTLY TRACKING THROUGH THE CWA... DRIVEN BY WEAK MOIST ISENTROPIC UPGLIDE IN THE LOW LEVELS AND A WEAK MID LEVEL WAVE... AND TO DELAY AFTERNOON CONVECTION IN THE WEST. HIGH-PW AIR (1.8-2.0") PERSISTS OVER CENTRAL NC WITH CONSIDERABLE MID AND HIGH DEBRIS CLOUDINESS FROM UPSTREAM MCS ACTION OVERSPREADING THE AREA FROM THE NW... AND THIS SHOULD SOMEWHAT CURB THE POTENTIAL FOR INSTABILITY THIS AFTERNOON. EXTRAPOLATION WOULD FAVOR ANY MCVS GENERATED BY LAST NIGHT`S THE CONVECTIVE COMPLEXES ACROSS SRN KS/MO/IL INTO WRN KY/TN LIKELY TRACKING WELL TO OUR SW... AND THIS TREND IS INDICATED BY THE NSSL WRF AND NCAR ENSEMBLE NEIGHBORHOOD PROBABILITIES. THESE MODEL PACKAGES ALSO SUGGEST THAT THE CHANCE FOR DEEP CONVECTION EAST OF HIGHWAY 1 THIS AFTERNOON INTO TONIGHT IS QUITE LOW... AND THE HRRR ALSO DEPICTS LITTLE TO NO COVERAGE OVER ALL BUT THE FAR WRN CWA AFTERNOON THROUGH AT LEAST 23Z. AFTER SLOWLY TRENDING THE COVERAGE OF SHOWERS DOWN THIS MORNING INTO EARLY AFTERNOON AS THEY TREND EASTWARD WITH WANING UPGLIDE... HAVE REDUCED CONVECTION CHANCES TO SLIGHT OR NIL IN THE EAST THIS AFTERNOON... AND HAVE CUT BACK COVERAGE IN THE WRN CWA A BIT AS WELL. GIVEN THE GENERALLY MOSTLY CLOUDY SKIES TODAY... HAVE CUT A COUPLE OF DEGREES OFF HIGHS... NOW RANGING FROM 84 TO 90. -GIH EARLIER DISCUSSION AS OF 255 AM: LATEST SURFACE ANALYSIS SHOWS WEAK HIGH PRESSURE EXTENDING INTO EASTERN VA AND NC. MEANWHILE A WARM FRONT EXTENDING FROM NEAR NASHVILLE TN SOUTHEAST TO NEAR SAVANNAH GA WAS BEGINNING TO SLOWLY LIFT NORTHWARD...LIKELY LIFTING THROUGH CENTRAL NC THIS AFTERNOON AND EVENING. FURTHER ALOFT...A RATHER WEAK DIFFLUENT NORTHWEST FLOW ALOFT WAS EXPECTED TO STRENGTHEN AND GRADUALLY BACK AND BECOME SOUTHWESTERLY BY LATE TONIGHT AS AN UPPER TROUGH DROPS INTO THE GREAT LAKES REGION. REGIONAL RADAR IMAGERY SHOWS SCT SHOWERS SLOWLY DEVELOPING AND EXPANDING ACROSS THE YADKIN VALLEY AND THE WESTERN PIEDMONT OF VA/NC/SC. THIS PRECIPITATION APPEARS TO BE ASSOCIATED WITH SOME ISENTROPIC UPGLIDE NEAR THE 305K SURFACE ENHANCED BY A WEAK SHORT WAVE ALOFT AND REMNANTS OF AN UPSTREAM MCS. NWP GUIDANCE SUGGESTS THAT THESE SHOWERS MAY BECOME MORE NUMEROUS AS THEY MOVE INTO THE WESTERN PIEDMONT TOWARD DAYBREAK. THE PRECIPITATION SHOULD BEGIN TO DIMINISH LATE THIS MORNING BEFORE REACHING THE COASTAL PLAIN. MUCH OF THE DAY TODAY SHOULD FEATURE A FAIR AMOUNT OF CLOUDINESS BUT MAINLY DRY CONDITIONS ACROSS CENTRAL NC. WITH LITTLE FORCING FOR ASCENT AND WITH ONLY WEAK INSTABILITY PRESENT THIS AFTERNOON AND FAIRLY MEAGER MID LEVEL LAPSE RATES...CONVECTIVE COVERAGE SHOULD BE RATHER LIMITED. THE ENVIRONMENT FOR CONVECTION BECOMES A LITTLE BIT MORE FAVORABLE THIS EVENING AND OVERNIGHT ACROSS THE WESTERN PIEDMONT AND TRIAD AREA AS LARGER SCALE FORCING APPROACHES AND MID LEVEL LAPSE RATE ACCORDINGLY INCREASE. STILL...CONVECTION ALLOWING MODELS HAVE TRENDED NOTICEABLY LESS ACTIVE FOR THIS AFTERNOON AND TONIGHT WITH NOCTURNAL CONVECTION NOW APPEARING MORE FOCUSED ACROSS VA/WV. HIGHS TODAY WILL BE COMPLICATED BY THE AMOUNT OF SUNSHINE AND WITH A TREND TOWARD LESS PRECIPITATION AND PERHAPS THINNER CLOUDS HAVE ADJUSTED MAXES UP EVER-SO-SLIGHTLY...HIGHS SHOULD RANGE SHOULD RANGE FROM 84 TO 91. LOWS TONIGHT WILL BE MODERATED BY A GOOD DEAL OF CLOUD COVER...LOWS SHOULD RANGE BETWEEN 69 AND 74 DEGREES. -BLAES && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 320 AM MONDAY... A STRENGTHENING UPPER TROUGH WILL MOVE ACROSS THE GREAT LAKES AND NORTHEAST DURING THE PERIOD WITH THE MAIN TROUGH AXIS SHIFTING ACROSS CENTRAL NC TOWARD DAYBREAK WEDNESDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS THE APPALACHIANS TUESDAY AFTERNOON AND THROUGH CENTRAL NC TUESDAY NIGHT...REACHING THE COAST TOWARD WEDNESDAY MORNING. SCATTERED CONVECTION IS EXPECTED AHEAD OF THE FRONT TUESDAY MORNING AND EARLY AFTERNOON. AS NOTED IN THE PREVIOUS DISCUSSION...THIS MAY PLAY A ROLE IN SUBSEQUENT CONVECTION TUESDAY AFTERNOON AND EVENING. WITH THE UPPER TROUGH CONTAINING MULTIPLE VORTICITY CENTERS...EXPECT SHOWERS AND THUNDERSTORMS TO MOVE ACROSS CENTRAL NC IN MULTIPLE CLUSTER OR BANDS THROUGHOUT THE AFTERNOON AS OPPOSED TO ONE WELL ORGANIZED LINE. THE CLOUDS AND PRECIPITATION WITH THESE CLUSTERS SHOULD RETARD INSTABILITY A BIT. SPC HAS CENTRAL NC OUTLOOKED WITH A MARGINAL THREAT OF SEVERE STORMS WHICH SEEMS REASONABLE GIVEN THE STRONGER DEEP LAYER FLOW AND BULK SHEAR VALUES OF 20-25 KTS SUGGESTING SOME STORM ORGANIZATION POSSIBLE. CAPE VALUES SHOULD RANGE FROM WEAK TO LOW END MODERATE WITH MLCAPE VALUES CLIMBING TO THE 750-1250 J/KG RANGE. THIS ENVIRONMENT WOULD SUPPORT A MULTICELLULAR/LINE SEGMENT CONVECTIVE MODE WITH A FEW STRONG STORMS AND POSSIBLY A SEVERE THUNDERSTORMS WITH DAMAGING WINDS THE MOST LIKELY THREAT. WITH A LINGERING SHORT WAVE TROUGH LIKELY TO MOVE ACROSS CENTRAL NC LATE TUESDAY EVENING...ANOTHER ROUND OF STORMS IS POSSIBLE WITH THIS FEATURE AND THE ASSOCIATED COLD FRONT. THE FRONT SHOULD EXIT THE RAH CWA BETWEEN 06-12Z AND BRING THE PRECIPITATION TO AN END. HIGHS IN THE 86 TO 91 RANGE WITH LOWS TUESDAY NIGHT IN THE 65 TO 73 RANGE. -BLAES && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 255 AM MONDAY... WEDNESDAY THROUGH FRIDAY... UPPER AIR PATTERN WILL BE DOMINATED BY A STRONG...AMPLIFIED RIDGE ALONG THE SPINE OF THE ROCKIES...AND A L/W TROUGH ALONG THE EASTERN SEABOARD. THIS TROUGH IS AT ITS MOST AMPLIFIED/DEEPEST AT MID WEEK THEN WEAKENS/BROADENS BY THE END OF THE WEEK. THIS SET-UP WILL SPREAD A DRIER STABLE AIR MASS INTO CENTRAL NC ON WEDNESDAY WHICH SHOULD LINGER THROUGH THE REMAINDER OF THE WORK WEEK AS AN AREA OF HIGH PRESSURE AT THE SURFACE BUILDS INTO THEN SETTLES OVERHEAD BY FRIDAY. ASIDE FROM A SLIGHT CHANCE OF A SHOWER EARLY WEDNESDAY OVER THE SE COUNTIES AS A COLD FRONT EXITS THE REGION...EXPECT DRY WEATHER WEDNESDAY THROUGH FRIDAY...AND TEMPERATURES AVERAGING FAIRLY CLOSE TO NORMAL FOR MID AUGUST. ONE THING THAT WILL BE LACKING WILL BE THE TYPICAL LATE SUMMER HUMIDITY AS AFTERNOON DEWPOINTS WILL DROP INTO THE 50S-LOWER 60S EACH AFTERNOON...ESPECIALLY ON THURSDAY AND FRIDAY. THIS WILL LEAD TO FAIRLY COMFORTABLE CONDITIONS FOR MID-AUGUST. FOR SATURDAY THROUGH SUNDAY...THE UPPER RIDGE BECOMES ORIENTATED SW- NE FROM THE DESERT SW INTO THE GREAT LAKES WHILE THE L/W TROUGH MAINTAINS A PRESENCE ALONG THE EASTERN SEABOARD. THE SFC HIGH WEAKENS WITH TIME BUT CONTINUES TO INFLUENCE THE SENSIBLE WEATHER OVER CENTRAL NC AS THE LOW LEVEL FLOW WILL MAINTAIN A FAIRLY MILD AIR MASS FOR THIS TIME OF YEAR. ENOUGH MOISTURE MAY CREEP BACK INTO SECTIONS OF OUR COASTAL PLAIN AND SANDHILL COUNTIES BY SUNDAY TO SPARK AN ISOLATED SHOWER OR STORM IN THE AFTERNOON. THE ATMOSPHERE WILL UNDERGO SLIGHT MODIFICATION...LEADING TO TEMPS SLIGHTLY ABOVE NORMAL BY SUNDAY. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 145 PM MONDAY... AVIATION CONDITIONS WILL BE SUB-VFR FOR THE MAJORITY OF THE NEXT 24 HOURS AT INT/GSO... HOWEVER AT RDU/FAY/RWI... THE SUB-VFR CONDITIONS WILL BE MORE SPORADIC WITH VFR DOMINATING AT LEAST THROUGH THIS EVENING. A MOIST SOUTHWESTERLY SURFACE FLOW INTO NC AHEAD OF AN APPROACHING COLD FRONT... COMBINED WITH LEFTOVER CLOUD COVER FROM STORM COMPLEXES TO THE WEST AND NORTHWEST OF NC... WILL KEEP MOSTLY CLOUDY SKIES AT ALL CENTRAL NC TERMINALS THROUGH TUE. CURRENT MVFR CIGS AT INT/GSO ARE EXPECTED TO LIFT BRIEFLY TO MAINLY VFR AFTER 21- 22Z TODAY... BUT THEN DROP BACK DOWN TO VFR AND POTENTIALLY IFR STARTING MID EVENING WITH NUMEROUS SHOWERS AND A FEW STORMS MOVING IN MAINLY AFTER 01Z... LASTING WELL INTO THE OVERNIGHT HOURS WITH PERIODIC MVFR VSBYS. MVFR CIGS AND PATCHY SHOWERS ARE LIKELY TO HOLD AT INT/GSO THROUGH THE END OF THE TAF VALID PERIOD... WITH PATCHY SHOWERS GIVING WAY TO MORE ORGANIZED THUNDERSTORMS TOWARD THE VERY END OF THE TAF VALID PERIOD (18Z TUE). RDU/FAY/RWI COULD SEE A PERIOD OF MVFR CIGS/VSBYS THROUGH THIS EVENING... BUT THE PROBABILITIES ARE LOW (HIGHER AT RDU THAN AT FAY/RWI BUT STILL LOW). AFTER 04Z... PATCHY SHOWERS ARE EXPECTED TO SHIFT EASTWARD NEARING THESE TAF SITES... AND THEY MAY GENERATE A PERIOD OF MVFR OR BRIEFLY IFR CIGS AND/OR MVFR VSBYS. SIMILAR TO INT/GSO... THE PATCHY MORNING SHOWERS MAY GIVE WAY TO SCATTERED STORMS IN THE AFTERNOON. LOOKING BEYOND 18Z TUE... SUB-VFR AND RAINY/STORMY CONDITIONS WILL DOMINATE AT ALL SITES THROUGH MUCH OF TUE AFTERNOON AND EVENING... WITH WINDS HOLDING FROM THE SW AT 9-15 KTS. AS THE FRONT PUSHES SE THROUGH THE AREA WITH HIGH PRESSURE BUILDING IN... WE`LL SEE A NW-TO- SE CLEARING TREND TO VFR CONDITIONS... WHICH WILL LAST INTO SAT WITH LARGELY DRY WEATHER. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BLAES SHORT TERM...BLAES LONG TERM...WSS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1140 AM CDT MON AUG 10 2015 .UPDATE... ISSUED AT 1124 AM CDT MON AUG 10 2015 LATEST VISIBLE SATELLITE SHOWING A CUMULUS FIELD INITIATING AS CONVECTIVE TEMPERATURES HAVE BEEN REACHED. QUESTION BECOMES WHETHER OR NOT A SHORTWAVE TROUGH SLIDING INTO CENTRAL NORTH DAKOTA AND THE JAMES RIVER VALLEY THIS AFTERNOON WILL BE ABLE TO GENERATE AN ISOLATED RAIN SHOWER(S) GIVEN SUCH A SHALLOW LAYER OF HIGHER RELATIVE HUMIDITIES PER TIME HEIGHT CROSS SECTIONS. THE HIGH RESOLUTION MODELS MAINTAIN THE IDEA OF ISOLATED CELLS DEVELOPING WHILE THE NAM/GFS KEEP IT DRY. THE RAP13 PUTS 0.01 ON THE SOUTH OF THE TURTLE MOUNTAINS AND PUSHES THIS AREA NEAR THE NORTHERN JAMES RIVER VALLEY. DESPITE THE EXPECTED CUMULUS FIELD GROWING IN COVERAGE WITH STRENGTHENING LOW LEVEL LAPSE RATES THIS AFTERNOON...WILL KEEP THE FORECAST DRY. THE CHANCE FOR RECEIVING MEASURABLE PRECIPIATION AND EXACTLY WHERE REMAINS VERY LOW AT THIS TIME. FORECAST REMAINS ON TRACK. UPDATE ISSUED AT 815 AM CDT MON AUG 10 2015 12Z BISMARCK SKEW-T SHOWS A CONVECTIVE TEMPERATURE OF 77F TODAY WHICH WILL BE REACHED BETWEEN 16Z-17Z/11AM-NOON CDT. EXPECTING SOME CUMULUS TO DEVELOP...HOWEVER TIME-HEIGHT CROSS SECTIONS SHOW LIMITED MOISTURE IN THE 850-700MB LAYER...WITH DRIER AIR ABOVE. LATEST WATER VAPOR IMAGERY LOOP REVEALS A SHORTWAVE/VORTICITY LOBE LOCATED IN FAR SOUTHEAST SASKATCHEWAN EXTENDING INTO WESTERN NORTH DAKOTA. THIS SHORTWAVE IS PICKED UP BY THE GFS AND IS FORECAST TO REACH THE JAMES RIVER VALLEY 21Z-00Z. 850MB-700MB LAPSE RATES FORECAST AT 9.5C/KM LATE THIS AFTERNOON IN CENTRAL NORTH DAKOTA. HI RESOLUTION MODELS HRRR/ARW WEST/NMM WEST INDICATE ISOLATED SHOWERS BETWEEN BISMARCK AND JAMESTOWN 21Z-00Z. THE PREVIOUS DISCUSSION MENTIONED THIS POTENTIAL. BUFKIT SOUNDINGS CURRENTLY MAINTAIN A SHALLOW POCKET OF MOISTURE REMAINING IN PLACE LATE THIS AFTERNOON WHEN THE MAX OMEGA/VERTICAL MOTION IN THE LOWEST LAYERS IS REACHED. WITH VERY MINIMAL AREAL COVERAGE AT THIS TIME...WILL KEEP THINGS DRY AND WATCH THE TRENDS AND ADJUST IF NEEDED LATER THIS MORNING. FORECAST REMAINS ON TRACK. UPDATE ISSUED AT 542 AM CDT MON AUG 10 2015 MADE A QUICK UPDATE TO ADD PATCHY FOG FROM HETTINGER...THOUGH WASHBURN...TO RUGBY AND ROLETTE. OBSERVATIONS THIS MORNING HAVE FAVORED THAT REGION FOR FOG...AND THIS ALSO LINES UP WITH THE LATEST ITERATIONS OF THE HRRR AND RAP13. A COUPLE ROGUE SHOWERS DEVELOPED OVERNIGHT IN PARTS OF LOGAN AND MCINTOSH COUNTIES...BUT THOSE HAVE DISSIPATED. THE REMAINDER OF THE FORECAST IS ON TRACK AND ONLY ADJUSTED TO CAPTURE THE LATEST OBSERVATIONS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 314 AM CDT MON AUG 10 2015 A QUIET START TO THE DAY IS EXPECTED WITH HIGH PRESSURE IN PLACE AT THE SURFACE ACROSS THE NORTHERN PLAINS. WILL HAVE TO MONITOR VISIBILITIES OVER THE NEXT FEW HOURS WITH LOW TEMPERATURE / DEWPOINT SPREADS...OTHERWISE SKIES WILL BE MOSTLY SUNNY EARLY THIS MORNING. A POTENTIAL CONCERN FOR TODAY IS THE CHANCE FOR AN ISOLATED SHOWER OR THUNDERSTORM THIS AFTERNOON. SOME OF THE HI-RES MODEL SOLUTIONS HAVE HINTED AT THE POSSIBILITY OF AN ISOLATED SHOWER AS LOW LEVEL LAPSE RATES STEEPEN THIS AFTERNOON. FORECAST SOUNDINGS SHOW ONLY A SMALL AREA OF INCREASED MOISTURE (RELATIVE HUMIDITY) THIS AFTERNOON AROUND H85...WITH VERY DRY AIR IN PLACE IN THE LOW LEVELS. FOR NOW...WILL STAY WITH THE DRY FORECAST AND ONLY SHOW SOME INCREASE IN CLOUDS AS CUMULUS DEVELOPS THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL BE IN THE 80S. TONIGHT WILL SEE CLEARING SKIES AS THE CUMULUS DISSIPATES DURING THE EVENING. LOWS SHOULD GENERALLY BE IN THE MID 50S TO NEAR 60. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 314 AM CDT MON AUG 10 2015 DETERMINISTIC MODELS AND ENSEMBLE OUTPUT CONTINUE TO INDICATE STRONG UPPER LEVEL RIDGE BUILDING ACROSS WESTERN NORTH AMERICA AND SLOWLY MOVING ACROSS THE NORTHERN PLAINS BY LATE WEEK AS DEEP UPPER LOW MOVES INTO THE PAC NW BY THU/FRI. HIGH TEMPS ACROSS WESTERN AND CENTRAL ND WILL REACH MID/UPPER 90S BY WEDNESDAY AND THURSDAY WITH THE HIGHEST TEMPS ACROSS THE WEST. TEMPS WILL REMAIN ABOVE NORMAL...BUT SLIGHTLY LOWER BY FRI AND SAT AS UPPER LEVEL RIDGE AXIS SLOWLY PUSHES EAST OF US. MODELS GENERATE SOME CONVECTIVE PRECIP TUE NIGHT AND WED WITH GFS INDICATING SOME ELEVATED INSTABILITY AND A LOW LEVEL JET STRENGTHENING TUE NIGHT AND UP TO 2000 J/KG OF SURFACE BASED CAPE ON WEDNESDAY. PROXIMITY OF UPPER LEVEL RIDGE AND GENERAL ANTICYCLONIC FLOW WILL LIMIT CONVECTIVE POTENTIAL...BUT AN ISOLATED SHOWER OR THUNDERSTORM IS NOT OUT OF THE QUESTION WITH MODELS SHOWING A FEW WEAK SHORTWAVE TROUGHS RIDING OVER THE RIDGE. BETTER CHANCE FOR PRECIP WILL BEGIN FRIDAY EVENING AS COLD FRONT MOVES THROUGH THE REGION ON SATURDAY PER GFS/ECMWF. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1124 AM CDT MON AUG 10 2015 VFR CIGS/VSBYS NEXT 24HR...WITH LIGHT WINDS. A SCT CUMULUS FIELD WILL GROW THROUGH MONDAY AFTERNOON WITH BKN CIGS AT 5000FT EXPECTED AT KJMS. THE RISK FOR ANY SHOWERS AT KBIS OR KJMS REMAIN TOO LOW FOR ANY MENTION AT THIS TIME. THE CUMULUS WILL DISSIPATE AFTER SUNSET WITH A CLEAR SKY TO FOLLOW FOR THE REMAINDER OF THE TAF PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...CK LONG TERM...JNS AVIATION...KS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
212 PM EDT MON AUG 10 2015 .SYNOPSIS... MUGGY TODAY. WEAK LOW PRESSURE DEVELOPS IN UPPER OHIO VALLEY MOVES NORTHEAST TONIGHT...DRAGGING A COLD FRONT THRU LATE TONIGHT AND TUESDAY MORNING. DRIER WITH COOLER NIGHTS WEDNESDAY INTO FRIDAY. && .NEAR TERM /THROUGH TUESDAY/... NO REAL CHANGES TO THE FORECAST. TWEAKED POPS A TAD TO ACCOUNT FOR DEVELOPING CONVECTION. OTHERWISE, NO OTHER CHANGES ARE EXPECTED. PREVIOUS DISCUSSION... ONE OF THOSE MUGGY AUGUST DAYS...PROBABLY WISE/BEST...NOT TO RUN WITH ANY ONE MODEL SOLUTION. WITH ADJUSTMENTS BEING MADE DURING THE COURSE OF THE DAY AND EVENING BASED ON THE MOST RECENT CONVECTIVE TRENDS. AT 07Z...ONE MID LEVEL VORT MAX STRETCHED OUT FROM SRN WV NNW TOWARD ZZV. IT SHOULD EXIT TO OUR EAST 12Z TO 14Z. NOT MUCH VIRGA IN THIS AIRMASS...SO IT WAS CAUSING SOME DISORGANIZED AREAS OF RW- OR SPRINKLES THIS PREDAWN. ANOTHER DISTURBANCE DROPPING SE FROM WRN KY TOWARD MIDDLE TENNESSEE. EVEN THOUGH MAIN CONVECTIVE CLUSTERS WILL DROP INTO TN...FEEL SOME OF ITS AFFECTS... IN THIS MUGGY AIR...COULD RIPPLE EAST AND CAUSE SHOWERS TO FORM INTO OUR TRI STATE AND SW VA THIS MORNING. MATTER OF FACT...THE 00Z NAM HAD THE EQUILIBRIUM LEVEL QUICKLY REACHING TOWARD 35 THSD BY 15Z AT HTS. YET...IT DOES NOT GET ANY HIGHER...THIS AFTERNOON OR EVENING. WEAK SURFACE LOW EXPECTED TO FORM IN THE UPPER OHIO VALLEY...SAY OVER OHIO...THIS AFTERNOON. THE WEAK WIND FLOW DOES INCREASE...MAYBE SOME 15 KNOTS AT 925 MBS BY 21Z ON THE RAP IN THE OHIO VALLEY COUNTIES. THE 06Z NAM DEEPENS THIS CIRCULATION EVEN MORE WITH SOME 25 KNOTS BY 00Z TUESDAY. 700 MB FLOW ONLY INCREASES TO ABOUT 20 TO 25 KNOTS. EXPECT CELL MOVEMENT THIS AFTERNOON AND EVENING TO BE ABOUT 25 KNOTS...WHICH IS NOT TOO FAST...AND NOT TOO SLOW. WILL BASE FORECAST ON ASSOCIATED TROF/FRONT FORM THE EXITING WEAK LOW PRESSURE...TO REACH INTO OUR SE OHIO AROUND 06Z TUESDAY...THEN REACHING BETWEEN CKB AND EKN TO NEAR HTS BY 12Z TUESDAY. TRYING TO TIME THE PREFRONTAL CONVECTION THAT FORMS IN OHIO THIS AFTERNOON...AND HOW FAST TO PUSH THE HIGHER POPS EAST... THROUGH WEST VIRGINIA...IS ONE HEADACHE. TRIED TO HAVE LIKELY POPS LATE THIS AFTERNOON IN SE OHIO...REACHING OHIO RIVER AT 00Z TUESDAY...THEN TOWARD EKN TO CRW 03Z TO 06Z TUESDAY. COULD SEE SOME SEVERE STORM DEVELOPMENT IN THIS HUMID ENVIRONMENT NEAR OUR SE OHIO COUNTIES IN THE OHIO VALLEY LATE THIS AFTERNOON...THEN MOVE EAST DURING THE EVENING INTO WV AND NRN KY . UPDATED THE HWO AT 630 AM...WILL HIGHLIGHT SOUTHEAST OHIO INTO WRN WV AND NE KENTUCKY FOR POSSIBLE STRONG TO SEVERE CONVECTION LATE THIS AFTERNOON OR THIS EVENING. WOULD NOT BE SURPRISED IF SPC UPDATES ON DAY 1...INCLUDED SOME SLIGHT RISK AREAS...AS THIS WHOLE SYSTEM EVOLVES/DEVELOPS. OVERALL THOUGH...THE FLOW NOT STRONG AND EL PEAKS ABOUT 35 THSD FT. ACTUALLY MOST COUNTIES...ESPECIALLY ALONG THE ROUTE 50 CORRIDOR COULD ACTUALLY USE SOME RAIN. MAXIMUM TEMPERATURE FORECAST TODAY DEPENDENT ON AFTERNOON COVERAGE OF CONVECTION... BUT TRIED TO STAY SLIGHTLY UNDER MOST 00Z MOS GUIDANCE...AND LOWER THAN THE OBSERVED ON SUNDAY. THE LOWEST CEILINGS SHOULD BE ASSOCIATED WITH THE FRONT...SO LEAVING LINGERING SHOWERS IN THE WAKE OF THE FRONT THRU 12Z TUESDAY NEAR THE OHIO RIVER...WITH SOME LIKELY POPS AT 12Z TUESDAY STILL OVER THE CENTRAL WV MOUNTAINS WITH THE FRONT. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... UPPER TROUGH ACROSS THE EASTERN U.S. ALONG WITH SEVERAL EMBEDDED SHORTWAVES...WILL KEEP A MENTION OF SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR THE SHORT TERM PERIOD. IN ADDITION...SOMEWHAT COOLER WEATHER WILL BE REALIZED TOO. THE POTENTIAL FOR A MORE POTENT WAVE IS POSSIBLE WEDNESDAY AFTERNOON...BUT THIS STILL REMAINS IN QUESTION AS MODELS VARY ON THE HANDLING OF THIS SITUATION. HIGH PRESSURE THEN NUDGES IN FROM THE WEST THIS THURSDAY AND FRIDAY...FOR A BRIEF BREAK IN THE WEATHER. && .LONG TERM /FRIDAY THROUGH MONDAY/... WEEKEND AND BEYOND REMAINS RATHER UNCERTAIN. ANOTHER FRONT WILL APPROACH OVER THE WEEKEND. GFS TENDS TO BRING THE FRONTAL BOUNDARY THROUGH THE CWA OVER THE WEEKEND...WITH SHOWERS AND THUNDERSTORMS. WHILE ECMWF IS A DRIER SOLUN...AND TENDS TO WASH OUT THE FRONT ACROSS THE NORTHERN PART OF CWA. FOR NOW...WENT AHEAD AND PUT A SLIGHT CHANCE TO CHANCE POPS ACROSS THE CWA. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... INCREASED THUNDERSTORM COVERAGE OVER MUCH OF THE REGION THIS AFTERNOON WITH LOCALIZED MVFR AND POSSIBLE IFR IN SHRA/TSRA/CIGS. COLD FRONT TO PUSH THROUGH OVERNIGHT TONIGHT WITH MVFR/IFR CIGS/SHRA/TSRA WITH THE FRONT. BEHIND THE FRONT LINGERING MVFR/IFR SHOWERS/FOG/CIGS TO 12Z TUESDAY AND LINGER PAST 12Z TUESDAY IN THE WV MOUNTAINS. CONDITIONS IMPROVE TO VFR...MAINLY BETWEEN 15Z- 18Z TUESDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: SPECIFIC TIMING AND DURATION OF ROUNDS OF CONVECTION THIS AFTERNOON AND OVERNIGHT TONIGHT WILL VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H M M M HTS CONSISTENCY H H H H H H M M M M M M BKW CONSISTENCY H H H H H H M H H H H H EKN CONSISTENCY H H H H H H M M M M M M PKB CONSISTENCY H H H H H H M M M M M M CKB CONSISTENCY H H H H H H H H H M M M AFTER 18Z TUESDAY... NEAR AND IN WAKE OF FRONT...LINGERING IFR CEILINGS IN LIGHTER SHOWERS THROUGH TUESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...JS SHORT TERM...SL LONG TERM...SL AVIATION...JS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
156 PM EDT MON AUG 10 2015 .SYNOPSIS... MUGGY TODAY. WEAK LOW PRESSURE DEVELOPS IN UPPER OHIO VALLEY MOVES NORTHEAST TONIGHT...DRAGGING A COLD FRONT THRU LATE TONIGHT AND TUESDAY MORNING. DRIER WITH COOLER NIGHTS WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... NO REAL CHANGES TO THE FORECAST. TWEEKED POPS A TAD TO ACCOUNT FOR DEVELOPING CONVECTION. OTHERWISE, NO OTHER CHANGES ARE EXPECTED. PREVIOUS DISCUSSION... ONE OF THOSE MUGGY AUGUST DAYS...PROBABLY WISE/BEST...NOT TO RUN WITH ANY ONE MODEL SOLUTION. WITH ADJUSTMENTS BEING MADE DURING THE COURSE OF THE DAY AND EVENING BASED ON THE MOST RECENT CONVECTIVE TRENDS. AT 07Z...ONE MID LEVEL VORT MAX STRETCHED OUT FROM SRN WV NNW TOWARD ZZV. IT SHOULD EXIT TO OUR EAST 12Z TO 14Z. NOT MUCH VIRGA IN THIS AIRMASS...SO IT WAS CAUSING SOME DISORGANIZED AREAS OF RW- OR SPRINKLES THIS PREDAWN. ANOTHER DISTURBANCE DROPPING SE FROM WRN KY TOWARD MIDDLE TENNESSEE. EVEN THOUGH MAIN CONVECTIVE CLUSTERS WILL DROP INTO TN...FEEL SOME OF ITS AFFECTS... IN THIS MUGGY AIR...COULD RIPPLE EAST AND CAUSE SHOWERS TO FORM INTO OUR TRI STATE AND SW VA THIS MORNING. MATTER OF FACT...THE 00Z NAM HAD THE EQUILIBRIUM LEVEL QUICKLY REACHING TOWARD 35 THSD BY 15Z AT HTS. YET...IT DOES NOT GET ANY HIGHER...THIS AFTERNOON OR EVENING. WEAK SURFACE LOW EXPECTED TO FORM IN THE UPPER OHIO VALLEY...SAY OVER OHIO...THIS AFTERNOON. THE WEAK WIND FLOW DOES INCREASE...MAYBE SOME 15 KNOTS AT 925 MBS BY 21Z ON THE RAP IN THE OHIO VALLEY COUNTIES. THE 06Z NAM DEEPENS THIS CIRCULATION EVEN MORE WITH SOME 25 KNOTS BY 00Z TUESDAY. 700 MB FLOW ONLY INCREASES TO ABOUT 20 TO 25 KNOTS. EXPECT CELL MOVEMENT THIS AFTERNOON AND EVENING TO BE ABOUT 25 KNOTS...WHICH IS NOT TOO FAST...AND NOT TOO SLOW. WILL BASE FORECAST ON ASSOCIATED TROF/FRONT FORM THE EXITING WEAK LOW PRESSURE...TO REACH INTO OUR SE OHIO AROUND 06Z TUESDAY...THEN REACHING BETWEEN CKB AND EKN TO NEAR HTS BY 12Z TUESDAY. TRYING TO TIME THE PREFRONTAL CONVECTION THAT FORMS IN OHIO THIS AFTERNOON...AND HOW FAST TO PUSH THE HIGHER POPS EAST... THROUGH WEST VIRGINIA...IS ONE HEADACHE. TRIED TO HAVE LIKELY POPS LATE THIS AFTERNOON IN SE OHIO...REACHING OHIO RIVER AT 00Z TUESDAY...THEN TOWARD EKN TO CRW 03Z TO 06Z TUESDAY. COULD SEE SOME SEVERE STORM DEVELOPMENT IN THIS HUMID ENVIRONMENT NEAR OUR SE OHIO COUNTIES IN THE OHIO VALLEY LATE THIS AFTERNOON...THEN MOVE EAST DURING THE EVENING INTO WV AND NRN KY . UPDATED THE HWO AT 630 AM...WILL HIGHLIGHT SOUTHEAST OHIO INTO WRN WV AND NE KENTUCKY FOR POSSIBLE STRONG TO SEVERE CONVECTION LATE THIS AFTERNOON OR THIS EVENING. WOULD NOT BE SURPRISED IF SPC UPDATES ON DAY 1...INCLUDED SOME SLIGHT RISK AREAS...AS THIS WHOLE SYSTEM EVOLVES/DEVELOPS. OVERALL THOUGH...THE FLOW NOT STRONG AND EL PEAKS ABOUT 35 THSD FT. ACTUALLY MOST COUNTIES...ESPECIALLY ALONG THE ROUTE 50 CORRIDOR COULD ACTUALLY USE SOME RAIN. MAXIMUM TEMPERATURE FORECAST TODAY DEPENDENT ON AFTERNOON COVERAGE OF CONVECTION... BUT TRIED TO STAY SLIGHTLY UNDER MOST 00Z MOS GUIDANCE...AND LOWER THAN THE OBSERVED ON SUNDAY. THE LOWEST CEILINGS SHOULD BE ASSOCIATED WITH THE FRONT...SO LEAVING LINGERING SHOWERS IN THE WAKE OF THE FRONT THRU 12Z TUESDAY NEAR THE OHIO RIVER...WITH SOME LIKELY POPS AT 12Z TUESDAY STILL OVER THE CENTRAL WV MOUNTAINS WITH THE FRONT. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... COLD FRONT WILL BE PUSHING EAST OF THE CWA BY MIDDAY TUESDAY. SEVERAL UPPER LEVEL SHORTWAVE TROUGHS WILL ROTATE AROUND A 500MB LOW OVER QUEBEC...SO LINGER POPS THROUGH MUCH OF THE DAY. OVERALL TROUGH AXIS PASSES LATE TUESDAY...HOWEVER NAM AND GFS SHOW ANOTHER RATHER POTENT SHORTWAVE TROUGH/VORT MAX DIGS IN ON WEDNESDAY. THE ECMWF KEEPS THINGS FARTHER NORTH. THIS FEATURE SHOULD BE FIGHTING INCREASINGLY DRIER AIR IN THE LOW LEVELS...BUT DID INCLUDE ISOLATED TO SCATTERED SHOWERS ACROSS NORTHERN AND EASTERN CWA. HIGH TEMPS WILL GENERALLY BE BELOW NORMAL THROUGH THE SHORT TERM. LOWS SHOULD BE JUST A TOUCH BELOW NORMAL TUESDAY NIGHT AS COLD AIR FILTERS IN...AND THEN A MILD 5-10 DEGREES BELOW NORMAL WEDNESDAY NIGHT. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE WEEKEND. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... INCREASED THUNDERSTORM COVERAGE OVER MUCH OF THE REGION THIS AFTERNOON WITH LOCALIZED MVFR AND POSSIBLE IFR IN SHRA/TSRA/CIGS. COLD FRONT TO PUSH THROUGH OVERNIGHT TONIGHT WITH MVFR/IFR CIGS/SHRA/TSRA WITH THE FRONT. BEHIND THE FRONT LINGERING MVFR/IFR SHOWERS/FOG/CIGS TO 12Z TUESDAY AND LINGER PAST 12Z TUESDAY IN THE WV MOUNTAINS. CONDITIONS IMPROVE TO VFR...MAINLY BETWEEN 15Z- 18Z TUESDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: SPECIFIC TIMING AND DURATION OF ROUNDS OF CONVECTION THIS AFTERNOON AND OVERNIGHT TONIGHT WILL VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H M M M HTS CONSISTENCY H H H H H H M M M M M M BKW CONSISTENCY H H H H H H M H H H H H EKN CONSISTENCY H H H H H H M M M M M M PKB CONSISTENCY H H H H H H M M M M M M CKB CONSISTENCY H H H H H H H H H M M M AFTER 18Z TUESDAY... NEAR AND IN WAKE OF FRONT...LINGERING IFR CEILINGS IN LIGHTER SHOWERS THROUGH TUESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...JS/KTB SHORT TERM...MZ LONG TERM...30 AVIATION...JS
AREA FORECAST DISCUSSION
NWS NORMAN OK
1226 PM CDT MON AUG 10 2015 .DISCUSSION... AVIATION DISCUSSION FOR THE 18Z TAFS IS BELOW. && .AVIATION... VFR CONDITIONS ARE EXPECTED TO CONTINUE. ISO-SCT -SHRA/-TSRA WILL AFFECT SOME SITES MAINLY NORTH OF KHBR- KOUN THROUGH 21Z. ADDITIONAL SHRA/TSRA MAY OCCUR AFTER 21Z...BUT ONLY KEPT PROB30 MENTION NEAR KWWR AND KGAG 06-10Z AS CONFIDENCE OF OCCURRENCE REMAINS RATHER LOW. PATCHES OF MVFR/IFR CONDITIONS MAY OCCUR NORTH OF KHBR-KOKC 08-16Z... PARTICULARLY NEAR KWWR AND KGAG...BUT DID NOT MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE. MBS && .PREV DISCUSSION... /ISSUED 1057 AM CDT MON AUG 10 2015/ UPDATE... LOWERED TEMPS A FEW DEGREES ACROSS THE NORTH AND ADJUSTED POPS SLIGHTLY. DISCUSSION... SCATTERED SHOWERS AND STORMS CONTINUE ALONG A WEAK MID LEVEL CONVERGENCE ZONE ACROSS NORTH CENTRAL OK. THIS ZONE WILL SLOWLY SHIFT SOUTHWARD DURING THE DAY BUT WITH LITTLE TO NO OTHER SUPPORT PRESENT (LLJ DISSIPATING) EXPECT COVERAGE WILL DIMINISH THROUGH THIS AFTERNOON. THE HRRR APPEARS TO HAVE A PRETTY GOOD HANDLE ON THE FORECAST SO WEIGHTED POPS HEAVILY TOWARDS IT. TEMPS WHERE ALSO LOWERED 2-4 DEGREES ACROSS NORTHERN OK...AND PORTIONS OF CENTRAL OK...WHERE CLOUD COVER WILL LIKELY LINGER THROUGH THE DAY. ALL UPDATED PRODUCTS HAVE BEEN SENT. PREV DISCUSSION... /ISSUED 338 AM CDT MON AUG 10 2015/ DISCUSSION... MAIN CONCERNS WILL BE PRECIP ACROSS THE NORTH AND HEAT FARTHER SOUTH TODAY AND THEN COOL-OFF AND PRECIP CHANCES THIS WEEK. CONT TO SEE SHOWERS AND THUNDERSTORMS DEVELOP ACROSS NORTHWEST INTO NORTHERN OKLAHOMA THIS MORNING NEAR A SLOW MOVING COLD FRONT. THIS FRONT IS A BIT SLOWER THAN MODELS HAVE BEEN SHOWING. THIS WILL ALLOW FOR TEMPS TO BE A BIT WARMER ACROSS PARTS OF THE AREA TODAY. BECAUSE OF THIS WE WILL END UP WITH SOME HIGHER HEAT INDICES AND WILL NECESSITATE THE NEED TO BRING THE HEAT ADVISORY FARTHER NORTH INTO CENTRAL OKLAHOMA. FRONT STILL EXPECTED TO PUSH SOUTH TOWARD THE RED RIVER BY TUESDAY MORNING. SLIGHTLY COOLER TEMPS EXPECTED BEHIND THE FRONT. AS THIS IS OCCURRING... UPPER RIDGE WILL BE BUILDING BACK NORTH ACROSS THE SOUTHERN/CENTRAL ROCKIES. MODELS CONT TO INDICATE AT LEAST A CHANCE FOR SOME ADDITIONAL PRECIP CHANCES INTO THE MIDDLE OF THE WEEK AS WE COME UNDER THE INFLUENCE OF WEAK NORTHWEST FLOW. HOWEVER TODAY`S MODEL RUNS HAVE SHIFTED THE MOISTURE PLUME FARTHER WEST AND KEEP MUCH IN THE WAY OF PRECIP CONFINED TO FAR WESTERN OKLAHOMA AND THE EASTERN TEXAS PANHANDLE AS WE GET INTO WED/THU TIMEFRAME. BEYOND THIS IT APPEARS THAT MOISTURE PLUME WILL DISSIPATE AND UPPER FLOW BECOMES MORE NORTHERLY AS UPPER RIDGE CONT BUILD NORTH AND NORTHEAST INTO THE CENTRAL AND NORTHERN PLAINS. ALTHOUGH DRY... THIS PATTERN SHOULD KEEP THE HOTTEST TEMPS TO OUR WEST AND NORTH BY LATE WEEK. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 96 74 90 70 / 30 20 10 10 HOBART OK 97 74 93 70 / 30 20 20 20 WICHITA FALLS TX 104 76 97 73 / 0 10 20 10 GAGE OK 91 70 87 68 / 50 30 30 20 PONCA CITY OK 92 73 89 68 / 60 10 0 10 DURANT OK 104 77 97 73 / 0 10 10 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR OKZ025>032-039>043- 045>048-050>052. TX...NONE. && $$ 03/14/17
AREA FORECAST DISCUSSION
NWS MEDFORD OR
231 PM PDT MON AUG 10 2015 .DISCUSSION...CURRENT WATER VAPOR IMAGE SHOWS THE UPPER LOW MARCHING SOUTH ALONG 130 W. IT ALSO SHOWS A WEAK SHORTWAVE MOVING INTO SOUTHWEST OREGON BRINGING HIGH AND MID LEVEL CLOUDS WHICH WILL CONTINUE TO MOVE NORTHEAST. THE STRONGER SHORTWAVE THAT MOVED THROUGH LAKE AND EASTERN KLAMATH COUNTY HAS MOVED NORTH OF OUR AREA AND INCREASED LIGHTNING STRIKES HAVE SHOWN UP IN NORTHEAST OREGON AND TOWARDS THE BLUE MOUNTAINS. GENERALLY CLEAR SKIES ARE IN ITS WAKE, BUT CUMULUS ARE STARTING TO BUILD UP OVER THE HIGHER TERRAIN ALONG AND EAST OF THE CASCADES AND NORTHERN CAL. LOOKING AT DATA SUGGEST THE BEST CHANCE FOR SCATTERED THUNDERSTORMS WILL BE LATE THIS AFTERNOON AND EVENING AND MOST CENTERED OVER THE CASCADES. THE MODELS SHOW THE LOWEST LI`S AND HIGHEST BOUNDARY LAYER CAPE VALUES AND THETA E CONVERGENCE IN THESE AREAS LATE THIS AFTERNOON. IN ADDITION THE 700 MB WINDS AND THE 700-500MB WINDS WILL BE FROM THE SOUTH, THEN SHIFT EVER SO SLIGHTLY TO THE SOUTH TO SOUTHWEST THIS EVENING. THEREFORE WE THINK THE MAJORITY OF THUNDERSTORMS WILL REMAIN IN THESE AREAS LATE THIS AFTERNOON AND EVENING. HOWEVER WINDS ALOFT WILL BE STRONGER, THEREFORE STORMS THAT FORM OVER WESTERN SISKIYOUS COUNTY AND SISKIYOU MOUNTAINS WILL GET CARRIED NORTH INTO THE WEST SIDE VALLEYS, BUT THEY WILL BE RUNNING IN AN ENVIRONMENT THAT IS LESS UNSTABLE AND ALSO WITH LESS MID LEVEL MOISTURE. ALSO STORMS THAT FORM OVER THE CASCADES COULD GET PULLED SLIGHTLY WESTWARD AND SCATTERED STORMS ARE POSSIBLE ALONG THE FOOTHILLS OF THE CASCADES IN EASTERN DOUGLAS COUNTY. OF NOTE THE PAST SEVERAL RUNS OF HIGH RES HRRR MODEL (WHICH UPDATES HOURLY) CONTINUES TO SHOW VERY LITTLE ACTIVITY FROM THE CASCADES WEST. IT ACTUALLY SHOWS A FRONTAL BOUNDARY ARRIVING AT THE COAST BY THIS EVENING USHERING MORE STABLE CONDITIONS BRINGING LIGHT RAIN WITH MOST OF THE CONVECTION IN MODOC AND LAKE COUNTY. MOST OF THE CONVECTIVE FEEDBACK IS EAST OF THE CASCADES IN PARTS OF KLAMATH AND LAKE COUNTY. NOT SURE IF THIS IS CORRECT, BUT IT MAY BE ON TO SOMETHING GIVEN THE CONSISTENCY FROM RUN TO RUN. SO ITS ENTIRELY POSSIBLE NOT MUCH WILL HAPPEN WEST OF THE CASCADES. TONIGHT, THE MODELS ARE IN FRIARLY GOOD AGREEMENT SHOWING WINDS AT 700 AND 700-500MB REMAIN SOUTH TO SOUTHWEST. THE NAM SHOWS MORE OF A SOUTHEAST COMPONENT OVERNIGHT TONIGHT, BUT THE GFS DOES NOT. THE NAM SHOWS LIFTED INDICES (LI`S) LOWERING TO AROUND -5 C ALONG THE COOS/DOUGLAS COUNTY LINE, BUT SUSPECT THAT MAY BE OVERDONE. IN CONTRAST THE GFS SHOWS LI`S AROUND -1C. THE NAM CONTINUES TO SHOW A SHORTWAVE MOVING WEST OF THE CASCADES OVERNIGHT TONIGHT, BUT THE GFS IS MUCH WEAKER. BECAUSE OF THE ABOVE MENTIONED REASONS, WE THINK THERE WILL BE NOCTURNAL STORMS WEST OF THE CASCADES, BUT THEY WILL BE ISOLATED. ON TUESDAY MOST OF THE INSTABILITY WILL BE WEST OF THE CASCADES. HOWEVER WE`LL ALSO HAVE A MARINE INFLUENCE NEAR THE COAST WHICH SHOULD STABILIZE THINGS SOME, SO WE DON`T THINK THUNDERSTORMS WILL BE A CONCERN THERE. SHORTWAVES WILL ROTATE IN FROM THE SOUTHEAST AHEAD OF THE UPPER LOW AND THIS IN COMBINATION WITH LOWEST LI`S AND HIGHEST BL CAPE CENTERED FROM WESTERN SISKIYOU COUNTY NORTHEAST TOWARDS EASTERN DOUGLAS COUNTY COULD BE ENOUGH TO GENERATE ISOLATED THUNDERSTORMS. OF NOTE THE HIGHEST BL CAPE VALUES AND LOWEST LI`S ARE IN THE NORTHERN CASCADES NORTH OF CRATER LAKE, SO THERE`S A CHANCE FOR SCATTERED STORMS THERE. NOT MUCH CHANGE IN THE PATTERN IS EXPECTED TUESDAY NIGHT THROUGH WEDNESDAY. THE UPPER LOW WILL REMAIN NEARLY STATIONARY, THEN SLOWLY MOVE NORTHWARD WEDNESDAY AFTERNOON AS THE UPSTREAM UPPER TROUGH MOVES TOWARDS WESTERN B.C. THE MODELS PUT THE GREATEST INSTABILITY ALONG THE CASCADES AND WESTERN SISKIYOU COUNTY TUESDAY NIGHT, THEN BECOMING MORE STABLE ON WEDNESDAY, THEREFORE THE CONCERN FOR NOCTURNAL STORMS EXIST AGAIN TUESDAY NIGHT, THEN THE THREAT OF STORMS SHIFTS NORTH WEDNESDAY. THE UPPER LOW WILL MOVE INLAND AND ACROSS THE AREA THURSDAY AFTERNOON AND WE EXPECT A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS ALONG WITH A BRIEF COOL DOWN. THE UPPER LOW WILL FINALLY KICK NORTHEAST OF THE AREA FRIDAY AFTERNOON AND A WEAK TROUGH REMAINS, BUT IT WILL STAY DRY WITH MILDER TEMPERATURES. WINDS WILL BE ANOTHER CONCERN, PARTICULARLY OVER THE HIGHER TERRAIN ALONG AND EAST OF THE CASCADES THIS AFTERNOON THROUGH AT LEAST THURSDAY AFTERNOON. ALSO WINDS ARE ALIGNED UP PRETTY WELL IN THE SHASTA VALLEY WITH 700MB WINDS BETWEEN 25-35 KTS, SOME OF WHICH COULD MIX DOWN NEAR THE SURFACE. THE MODEL GUIDANCE SHOWS WIND GUSTS BETWEEN 45-50 KTS, BUT SUSPECT THIS MAY BE A BIT OVERDONE. THIS IS BECAUSE THE PRESSURE GRADIENT IS NOT STRONG LIKE WE TYPICALLY SEE IN THE WINTER THAT WOULD PRODUCE WIND GUST OF THIS MAGNITUDE. SO WHILE WE EXPECT WINDS TO INCREASE AROUND THE WEED AREA, THEY WON`T BE ENOUGH TO REACH ADVISORY CRITERIA. A THERMAL TROUGH WILL DEVELOP ALONG THE COAST FRIDAY NIGHT THROUGH SATURDAY WITH INCREASING OFFSHORE FLOW. THE PATTERN THAT IS SETTING UP IS FAVORABLE FOR A CHETCO EFFECT AND THE HIGH TEMPERATURES IN BROOKINGS COULD EASILY GET INTO THE MID TO UPPER 80S OR LOW 90S. MEANWHILE TEMPERATURES WILL HEAT UP IN THE WEST SIDE VALLEYS WITH READINGS IN THE LOWER TO MID 90S. DRY CONDITIONS CONTINUE SUNDAY AND THE THERMAL TROUGH WILL SHIFT INLAND OVER THE WEST SIDE VALLEYS WITH TEMPERATURES EXPECTED TO BE IN THE MID 90S. KEEP IN MIND WHILE THE MODELS REMAIN IN GOOD AGREEMENT WITH THE OVERALL PATTERN THE NEXT FEW DAYS, THE MAIN CHALLENGE WILL BE ADDRESSING THE DETAILS OF THE WEATHER, ESPECIALLY AS IT RELATES TO THUNDERSTORM COVERAGE, SHOWERS AND PATCHY TO AREAS OF SMOKE. CONFIDENCE REMAINS LOW REGARDING THE MOST FAVORABLE AREAS FOR THUNDERSTORMS. THEREFORE DETAILS ON THIS COULD CHANGE FROM ONE DAY TO THE NEXT SO STAY TUNED FOR THE LATEST UPDATES. -PETRUCELLI && .AVIATION...FOR THE 10/18Z TAF CYCLE...ALONG THE COAST...IFR/MVFR CIGS OFFSHORE WILL MOVE BACK ONSHORE THIS EVENING...THEN PERSIST THROUGH MID-MORNING TUESDAY. INLAND...VFR CONDITIONS WILL PREVAIL THROUGH TUESDAY MORNING...EXCEPT FOR AREAS OF MVFR VSBYS IN SMOKE. ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON WITH THE GREATER COVERAGE OVER THE CASCADES AND SISKIYOUS. ISOLATED THUNDERSTORMS ARE EXPECTED TO CONTINUE INTO THE MORNING WEST OF THE CASCADES. STORMS MAY BRING ERRATIC AND GUSTY WINDS AND LOCAL OBSCURATION OF HIGHER TERRAIN. && .MARINE...UPDATED 230 PM PDT MONDAY 10 AUGUST 2015...A WEAK SURFACE PRESSURE PATTERN WILL RESULT IN CALM WINDS AND SEAS OVER THE NEXT SEVERAL DAYS, ALTHOUGH AN UPPER LEVEL DISTURBANCE COULD BRING A FEW THUNDERSTORMS TO THE COASTAL WATERS TONIGHT INTO EARLY TUESDAY. A THERMAL TROUGH WILL DEVELOP NEAR THE COAST FRIDAY AND SATURDAY, BRINGING WITH IT STRONG NORTH WINDS AND CHOPPY SEAS, ESPECIALLY IN THE OUTER WATERS SOUTH OF CAPE BLANCO. ALTHOUGH STILL TOO FAR OUT IN RANGE TO BE CERTAIN, GALES AND VERY STEEP SEAS ARE POSSIBLE THIS WEEKEND INTO EARLY NEXT WEEK. -BPN && .FIRE WEATHER...UPDATED 230 PM PDT MONDAY 10 AUGUST 2015...SOUTHERLY FLOW INCREASED TODAY...AND SO DID CLOUD COVER. THIS IS INHIBITING THUNDERSTORM DEVELOPMENT OVER THE AREA...BUT SOME ARE STILL EXPECTED TO DEVELOP. SCATTERED COVERAGE WILL EVENTUALLY DEVELOP OVER THE CASCADES WITH ISOLATED COVERAGE OVER MOST OF THE OTHER INLAND AREAS. ISOLATED THUNDERSTORMS MAY PERSIST THROUGH THE NIGHT...THEN BECOME SCATTERED AGAIN OVER THE NORTHERN CASCADES TUESDAY AFTERNOON. GUSTY SOUTH WINDS HAVE ALREADY DEVELOPED AND WILL CONTINUE THROUGH THURSDAY...WHEN IT MAY BE ESPECIALLY WINDY ON THE EAST SIDE DUE TO AN UPPER LEVEL TROUGH MOVING ONSHORE. AFTER THE TROUGH MOVES INLAND ...OFFSHORE LOW LEVEL FLOW WILL DEVELOP OVER THE COAST RANGE FRIDAY NIGHT INTO SATURDAY NIGHT. && .MFR WATCHES/WARNINGS/ADVISORIES... OR... RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR ORZ616-617-622>624. RED FLAG WARNING FROM 5 PM TO 11 PM PDT TUESDAY FOR ORZ617-623. CA...RED FLAG WARNING FROM 2 PM TO 8 PM PDT TUESDAY FOR CAZ281. PACIFIC COASTAL WATERS...NONE. $$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
957 AM PDT MON AUG 10 2015 .DISCUSSION...CURRENT VISIBLE IMAGE SHOWS A BAND OF CLOUDS MOVING NORTH IN ASSOCIATION WITH A SHORTWAVE IN EASTERN KLAMATH AND LAKE COUNTY. RETURNS FROM THIS FEATURE HAVE BEEN WEAK AND THERE HAVE BEEN NO REPORTS OF ANY RAINFALL. ALSO NO LIGHTING STRIKES HAVE BEEN OBSERVED IN OUR FORECAST AREA. THUS HAVE REMOVED POPS AND THUNDER FROM THE FORECAST IN THESE AREAS. THE WATER VAPOR IMAGE SHOWS THE UPPER LOW MARCHING SOUTH ALONG 130 W. IT`S ALSO PICKING UP ON A WEAK SHORTWAVE MOVING INTO NORTHWEST CALIFORNIA AND THIS WILL MOVE NORTHEAST. LOOKING AT DATA THIS MORNING WOULD SUGGEST THE BEST CHANCE FOR SCATTERED THUNDERSTORMS WILL BE LATE THIS AFTERNOON AND EVENING AND MOST CENTERED OVER THE CASCADES, SISKIYOUS AND WESTERN SIKSYOU COUNTY. THE MODELS SHOW THE LOWEST LI`S AND HIGHEST BOUNDARY LAYER CAPE VALUES AND THETA E CONVERGENCE IN THESE AREAS LATE THIS AFTERNOON. IN ADDITION THE 700 MB WINDS AND THE 700-500MB WINDS ARE FROM THE SOUTH THROUGH EARLY THIS AFTERNOON, THEN SHIFT EVER SO SLIGHTLY TO THE SOUTH TO SOUTHWEST LATE THIS AFTERNOON AND EVENING. THEREFORE WE THINK THE MAJORITY OF THUNDERSTORMS WILL REMAIN IN THESE AREAS LATE THIS AFTERNOON AND EVENING. HOWEVER WINDS ALOFT WILL BE STRONGER, THEREFORE STORMS THAT FORM OVER WESTERN SIKSYOU COUNTY AND SISKIYOU MOUNTAINS WILL GET CARRIED NORTH INTO THE WEST SIDE VALLEYS, BUT THEY WILL BE RUNNING IN AN ENVIRONMENT THAT IS LESS UNSTABLE AND ALSO WITH LESS MID LEVEL MOISTURE. ALSO STORMS THAT FORM OVER THE CASCADES COULD GET PULLED SLIGHTLY WESTWARD AND SCATTERED STORMS ARE POSSIBLE ALONG THE FOOTHILLS OF THE CASCADES IN EASTERN DOUGLAS COUNTY. OF NOTE THE HIGH RES HRRR MODEL SHOWS VERY LITTLE ACTIVITY FROM THE CASCADES WEST. IT ACTUALLY SHOWS A FRONTAL BOUNDARY ARRIVING AT THE COAST BY THIS EVENING USHERING MORE STABLE CONDITIONS BRINGING LIGHT RAIN WITH MOST OF THE CONVECTION IN MODOC AND LAKE COUNTY. NOT SURE IF THIS IS CORRECT, BUT IT MAY BE ON TO SOMETHING GIVEN THE BAND OF CLOUDS JUST OFF THE COAST WHICH WILL PUSH INLAND LATER THIS AFTERNOON. FOR TONIGHT, THE MODELS ARE IN FRIARLY GOOD AGREEMENT SHOWING WINDS AT 700 AND 700-500MB REMAIN SOUTH TO SOUTHWEST. THE NAM SHOWS MORE OF A SOUTHEAST COMPONENT OVERNIGHT TONIGHT, BUT THE GFS DOES NOT. THE NAM SHOWS LIFTED INDICES (LI`S) LOWERING TO AROUND -5 C ALONG THE COOS/DOUGLAS COUNTY LINE, BUT SUSPECT THAT MAY BE OVERDONE. IN CONTRAST THE GFS SHOWS LI`S AROUND -1C. THE NAM CONTINUES TO SHOW A SHORTWAVE MOVING WEST OF THE CASCADES OVERNIGHT TONIGHT, BUT THE GFS IS MUCH WEAKER. BECAUSE OF THE ABOVE MENTIONED REASONS, WE THINK THUNDERSTORMS WILL BE ISOLATED WEST OF THE CASCADES. -PETRUCELLI && .AVIATION...FOR THE 10/12Z TAF CYCLE...ALONG THE COAST...MVFR TO IFR CIGS ARE LINGERING MAINLY NORTH OF CAPE BLANCO THIS MORNING, BUT EXPECT THAT THIS WILL BURN BACK OFFSHORE BY LATE MORNING WITH VFR CONDITIONS EXPECTED TO LAST INTO TONIGHT. INLAND...VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS. HOWEVER THUNDERSTORMS WILL BE A CONCERN AFTER 21Z AND THEY COULD BRING ERRATIC AND GUSTY WINDS. -PETRUCELLI && .MARINE...UPDATED 830 AM PDT MONDAY 10 AUGUST 2015...A WEAK SURFACE PRESSURE PATTERN WILL PREVAIL THROUGH THURSDAY NIGHT WITH OCCASIONALSHOWERS. WINDS WILL BE 10 KT OR LESS AND SEAS LESS THAN 4 FEET THROUGH THURSDAY NIGHT. AN UPPER LEVEL DISTURBANCE WILL ALSO BRING A SLIGHT CHANCE FOR THUNDERSTORMS TO THE COASTAL WATERS MONDAY NIGHT INTO EARLY TUESDAY. A THERMAL TROUGH WILL DEVELOP NEAR THE COAST FRIDAY AND SATURDAY...BRINGING WITH IT STRONG NORTH WINDS AND CHOPPY SEAS...STRONGEST IN THE OUTER WATERS SOUTH OF CAPE BLANCO. && .FIRE WEATHER...UPDATED 345 AM PDT MONDAY 10 AUGUST 2015...SOUTHERLY FLOW INCREASES TODAY...BRINGING MONSOONAL MOISTURE TO THE AREA ALONG WITH MODERATE TO STRONG SOUTHERLY TO SOUTHWESTERLY WINDS...ESPECIALLY OVER THE RIDGES AND OCCASIONALLY IN NORTH TO SOUTH ORIENTED VALLEYS SUCH AS THE SHASTA VALLEY. THUNDERSTORMS WILL DEVELOP...AFTER A WEAK SHORT WAVE BRINGS CLOUDS AND AN OCCASIONAL CLAP OF THUNDER EARLY THIS MORNING AS IT MOVES THROUGH FROM THE SOUTH...THIS AFTERNOON AND EVENING. STORMS WILL LIKELY DEVELOP IN THE MOUNTAINS SOUTH OF WESTERN SISKIYOU COUNTY AS THE CLOUDS CLEAR FROM THE SOUTH...BUILDING NORTH INTO THE CASCADES LATER IN THE AFTERNOON. THE BEST AREA OF THUNDERSTORM INITIATION SHOULD BE IN WESTERN SISKIYOU COUNTY TO THE NORTH AND EAST INTO THE CASCADES. STRONG STEERING 700 MB WINDS WILL THEN MOVE THESE CELLS TO THE NORTH- NORTHWEST ACROSS THE WEST SIDE IN A BROAD AREA OF INSTABLITY WITH CELLS MOVING GENERALLY AT 15-20 MPH TO THE NORTH AND NORTH- NORTHWEST. ELEVATED INSTABILITY REMAINS OVER NIGHT ON THE WEST SIDE...AND WITH ANOTHER SHORT WAVE MOVING ACROSS OVERNIGHT IN THIS AREA OF ELEVATED INSTABLITY HAVE EXTENDED THE RED FLAG WARNING TO 15Z AND MOVED THE AREA UP TO THE COAST AND NORTH TO INCLUDE ONLY THE SW OREGON FIRE WEATHER ZONES. -SVEN && .PREV DISCUSSION... /ISSUED 406 AM PDT MON AUG 10 2015/ DISCUSSION...AN UPPER LEVEL LOW PRESSURE SYSTEM IS SPINNING NEAR 47N AND 130W EARLY THIS MORNING. THE MAIN BAND OF RAIN WITH THIS SYSTEM IS BEYOND ABOUT 60 NM FROM SHORE THIS MORNING AND WILL LIKELY STAY OUT OVER THE WATER AND GRADUALLY WEAKEN OVER TIME. MEANWHILE, WATER VAPOR IMAGERY IS SHOWING A SHORT WAVE LIFTING NORTHWARD THROUGH THE SACRAMENTO VALLEY THIS MORNING AND SOME MID- LEVEL MOISTURE IS FUNNELING NORTHWARD IN ADVANCE OF THIS FEATURE. RADAR IS SHOWING SOME SHOWERS ENTERING SOUTHERN MODOC COUNTY CURRENTLY AND THERE HAVE BEEN SOME ISOLATED CLOUD TO GROUND STRIKES IN LASSEN COUNTY IN THE LAST HOUR. SINCE THESE SHOWERS ARE MOVING INTO AN AREA OF ELEVATED INSTABILITY, EXPECT SOME ISOLATED THUNDERSTORMS FROM MODOC INTO LAKE COUNTY, ESPECIALLY NEAR THE WARNERS THROUGH THIS MORNING. THIS SHORT WAVE WILL LIFT NORTHWARD THROUGH THE AREA BY EARLY THIS AFTERNOON. OF NOTE, WINDS BEGIN TO ALIGN WITH THE SHASTA VALLEY THIS AFTERNOON AND EVENING AND THEY`LL REMAIN THAT WAY THROUGH THURSDAY, SO WE SHOULD SEE SOME PRETTY GOOD SOUTH TO SOUTHEAST WIND GUSTS NEAR WEED (30-40 MPH)...JUST SHY OF WIND ADVISORY LEVELS. AS THE UPPER LOW DIGS SOUTHWARD TODAY, AN UNSTABLE AIR MASS WILL DEVELOP OVER THE MARBLE/SISKIYOU/CASCADE MOUNTAINS WITH STEEP LAPSE RATES (>7.5C/KM) AND AMPLE SURFACE-BASED CAPE (500-1000 J/KG). COMPUTED LIS ARE -2 TO -6. MID-UPPER LEVEL WIND SHEAR WILL ALSO INCREASE (45-55KT) AS SHORTWAVES RIDE NORTH, THEN NORTHWESTWARD ON INCREASING SOUTH-SOUTHEAST FLOW ALOFT. MID-LEVEL MOISTURE (700-500MB) APPEARS TO BE ONE POTENTIAL LIMITING FACTOR FOR CONVECTION TODAY, BUT THERE SHOULD STILL BE ISOLATED TO SCATTERED THUNDERSTORMS. SINCE WINDS ALOFT ARE PRETTY STRONG, ANY STORMS THAT DO DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS AND SMALL HAIL. THEY WILL ALSO BE ABLE TO MOVE OUT AND OVER THE VALLEYS THIS EVENING DUE TO THE STRONG SOUTH-SOUTHEAST MID- LEVEL FLOW (25-35KT). IT SHOULD BE NOTED THAT THE AIR MASS WILL REMAIN UNSTABLE TONIGHT INTO TUESDAY MORNING WEST OF THE CASCADES AND ADDITIONAL STORMS MAY CONTINUE TO DEVELOP AND MOVE NORTHWESTWARD. INSTABILITY IS ELEVATED AND THIS MAY RESULT IN STORMS MOVING OUT OVER THE OCEAN. FOR THESE REASONS, WE HAVE EXPANDED THE AREA OF THE CURRENT RED FLAG WARNINGS WESTWARD TO THE COAST, BUT PRIMARILY NORTH OF PORT ORFORD. BY TUESDAY AFTERNOON, THE UPPER LOW WILL BE RIGHT NEAR 40N AND 130W. SHORT WAVE ACTIVITY IS MINIMAL THROUGH ABOUT EARLY AFTERNOON, BUT ANOTHER ONE IS EXPECTED TO ROTATE INTO THE AREA DURING THE LATE AFTERNOON OR EVENING. THE BEST INSTABILITY IS FROM THE CASCADES WESTWARD, BUT AGAIN, MOISTURE IS SOMEWHAT LACKING. WE`LL MAINTAIN THE SLIGHT CHANCE TO CHANCE THUNDER THREAT. THE AIR MASS STABILIZES ACROSS THE SOUTH AND EAST, SO IT SHOULD JUST BE PARTLY TO MOSTLY SUNNY THERE WITH SOME GUSTY AFTERNOON BREEZES. ON WEDNESDAY, THE UPPER LOW WILL STILL BE IN THE SAME GENERAL POSITION NEAR 40N AND 130 W, BUT MODELS ARE SHOWING MUCH LESS INSTABILITY ACROSS THE REGION. WE HAVE BACKED OFF ON THE THUNDER THREAT, WITH JUST A SLIGHT CHANCE OF SHOWERS AGAIN MAINLY FROM THE CASCADES WESTWARD. BY WEDNESDAY NIGHT, AS HAS BEEN ADVERTISED FOR SEVERAL RUNS NOW, A SHORT WAVE DISTURBANCE WILL MOVE INTO BRITISH COLUMBIA AND THIS SHOULD ALLOW THE UPPER LOW TO EJECT AND MOVE ACROSS THE PACIFIC NORTHWEST ON THURSDAY. THIS SHOULD BRING AN AREA OF SHOWERS AND THUNDERSTORMS ACROSS A GOOD PORTION OF THE CWA ALONG AND WEST OF THE CASCADES THROUGH THURSDAY EVENING ALONG WITH A COOL DOWN. THE AIR MASS WILL DRY OUT THURSDAY NIGHT, BUT A PIECE OF THE UPPER TROUGH WILL HANG BACK OVER THE AREA FRIDAY. THIS WILL KEEP TEMPERATURES FROM WARMING UP TOO QUICKLY, BUT WE DO EXPECT MODERATING TEMPS FOR THE WEEKEND. SPILDE AVIATION...FOR THE 10/12Z TAF CYCLE...ALONG THE COAST...MVFR TO IFR CIGS ARE HANGING OFFSHORE THIS MORNING WITH SOME STRATUS DEVELOPING VCTY KOTH. EXPECT THAT THIS WILL MOVE ONTO THE SHORE BRIEFLY BEFORE BURNING BACK OFFSHORE BY LATE MORNING. INLAND...VFR CONDITIONS WILL PREVAIL THIS MORNING...EXCEPT FOR AREAS OF SMOKE MOSTLY OVER SOUTHERN AND EASTERN DOUGLAS COUNTY...JACKSON COUNTY...AND THE UPPER KLAMATH BASIN. AFTER A WEAK DISTURBANCE MOVES MID CLOUDS THROUGH THE REGION EARLY THIS MORNING FROM THE SOUTH... CUMULUS WILL DEVELOP EARLY THIS AFTERNOON OVER THE AREA FROM WESTERN SISKIYOU COUNTY ACROSS THE SISKIYOU MOUNTAINS TO THE SOUTHERN OREGON CASCADES AND NORTHERN PORTIONS OF KLAMATH AND LAKE COUNTIES WITH ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED TO FORM AROUND 22Z AND LATER THIS AFTERNOON AND CONTINUE INTO THE EVENING. WITH ELEVATED INSTABILITY AND A SHORT WAVE MOVING ACROSS WEST OF THE CASCADES AT LEAST ISOLATED THUNDERSTORMS ARE EXPECTED TO CONTINUE INTO THE MORNING WEST OF THE CASCADES. STORMS MAY BRING ERRATIC AND GUSTY WINDS. -SVEN MARINE...UPDATED 345 AM PDT MONDAY 10 AUGUST 2015...A WEAK SURFACE PRESSURE PATTERN WILL PREVAIL THROUGH THURSDAY NIGHT WITH OCCASIONAL SHOWERS ALONG WITH LIGHT WINDS AND SEAS. AN UPPER LEVEL DISTURBANCE WILL ALSO BRING A SLIGHT CHANCE FOR THUNDERSTORMS TO THE COASTAL WATERS TONIGHT INTO EARLY TUESDAY. WIND DIRECTION WILL VARY FROM SOUTH TO NORTH THROUGH THURSDAY...BUT WILL REMAIN BELOW 10 KT WITH SEAS 4 FEET OR LESS. THE THERMAL TROUGH WILL RETURN ON FRIDAY AND STRENGTHEN INTO SATURDAY...BRINGING A RETURN OF MODERATE TO STRONG NORTH WINDS AND CHOPPY SEAS. THESE WINDS WILL BE STRONGEST IN THE OUTER WATERS SOUTH OF CAPE BLANCO. -SVEN FIRE WEATHER...UPDATED 345 AM PDT MONDAY 10 AUGUST 2015...SOUTHERLY FLOW INCREASES TODAY...BRINGING MONSOONAL MOISTURE TO THE AREA ALONG WITH MODERATE TO STRONG SOUTHERLY TO SOUTHWESTERLY WINDS...ESPECIALLY OVER THE RIDGES AND OCCASIONALLY IN NORTH TO SOUTH ORIENTED VALLEYS SUCH AS THE SHASTA VALLEY. THUNDERSTORMS WILL DEVELOP...AFTER A WEAK SHORT WAVE BRINGS CLOUDS AND AN OCCASIONAL CLAP OF THUNDER EARLY THIS MORNING AS IT MOVES THROUGH FROM THE SOUTH...THIS AFTERNOON AND EVENING. STORMS WILL LIKELY DEVELOP IN THE MOUNTAINS SOUTH OF WESTERN SISKIYOU COUNTY AS THE CLOUDS CLEAR FROM THE SOUTH...BUILDING NORTH INTO THE CASCADES LATER IN THE AFTERNOON. THE BEST AREA OF THUNDERSTORM INITIATION SHOULD BE IN WESTERN SISKIYOU COUNTY TO THE NORTH AND EAST INTO THE CASCADES. STRONG STEERING 700 MB WINDS WILL THEN MOVE THESE CELLS TO THE NORTH- NORTHWEST ACROSS THE WEST SIDE IN A BROAD AREA OF INSTABILITY WITH CELLS MOVING GENERALLY AT 15-20 MPH TO THE NORTH AND NORTH- NORTHWEST. ELEVATED INSTABILITY REMAINS OVER NIGHT ON THE WEST SIDE...AND WITH ANOTHER SHORT WAVE MOVING ACROSS OVERNIGHT IN THIS AREA OF ELEVATED INSTABILITY HAVE EXTENDED THE RED FLAG WARNING TO 15Z AND MOVED THE AREA UP TO THE COAST AND NORTH TO INCLUDE ONLY THE SW OREGON FIRE WEATHER ZONES. -SVEN && .MFR WATCHES/WARNINGS/ADVISORIES... OR... RED FLAG WARNING FROM 11 PM THIS EVENING TO 8 AM PDT TUESDAY FOR ORZ615-619. RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 AM PDT TUESDAY ABOVE 500 FEET FOR FOR ORZ616-620. RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING FOR ORZ617-621>624. CA...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING FOR CAZ280-281. FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY EVENING FOR CAZ281. PACIFIC COASTAL WATERS...NONE. $$ MAP/MAP/MAP
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
614 PM EDT MON AUG 10 2015 .SYNOPSIS... A FRONTAL SYSTEM OVER THE OHIO VALLEY WILL MOVE THROUGH THE REGION OVERNIGHT AND EARLY TUESDAY. COOLER AND DRIER AIR WILL FOLLOW FOR THE MIDWEEK PERIOD. TEMPERATURES WILL REBOUND LATE THIS WEEK WITH HIGH PRESSURE BUILDING EAST FROM THE MID MISSISSIPPI VALLEY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... EARLY EVENING RADAR MOSAIC SHOWING WIDESPREAD SHRA/TSRA ACROSS NW PA IN ADVANCE OF APPROACHING UPPER TROF. SPC MESOANALYSIS INDICATING SOME MODEST CAPES OF ARND 1000 J/KG ACROSS WESTERN PA...WHERE THERE WAS SOME SUNSHINE EARLIER TODAY. FURTHER EAST...MOIST SERLY FLOW YIELDING MARINE LYR STRATUS BUT NO PRECIP ACROSS MOST OF CENTRAL PA. EXPECT SHRA TO OVERSPREAD THE REGION FROM WEST TO EAST DURING THE LATE EVENING HOURS...AS UPPER TROF AND PRECEDING LL JET/PLUME OF ANOMALOUS PWATS OVERSPREAD THE STATE. SPC HAD PLACED THE ALLEGHENY PLATEAU IN A MRGL RISK AREA FOR SVR WX THIS EVENING. HOWEVER...GIVEN DIMINISHING CAPES AND NEARLY NON-EXISTENT DCAPES...BELIEVE THE THREAT OF SVR WX IS LOW. GREATER RISK MAY BE ISOLD FLOODING ACROSS THE NW MTNS...WHERE LINGERING INSTABILITY...COMBINED WITH SURGING PWATS...COULD PRODUCE LOCALIZED EXCESSIVE RAINFALL. HPC HAS OUTLINED OUR NORTHERN AREAS FOR POTENTIALLY HEAVY RAINS. SHORT TERM GUIDANCE SHOWS A PRETTY QUICK PROGRESSION ACROSS THE STATE OF THE LOW LEVEL JET AND AXIS OF DEEPEST MOISTURE. WILL HAVE TO WATCH FOR THE POTENTIAL FOR TRAINING CONVECTION IN THE MOISTURE RICH TROPICAL AIRMASS. SPC SSEO AND LATEST HRRR TARGET THE NW MTNS FOR LOCALIZED AMTS 3+ INCHES. HAVE MENTIONED SLIGHT RISK OF FLOODING ACROSS THIS AREA IN THE HWO...BUT GIVEN RECENT DRYNESS...FEEL ODDS OF FLASH FLOODING NOT HIGH ENOUGH FOR A WATCH ATTM. STRONG FRONTAL PASSAGE...ANOMALOUS PWATS AND LATEST GEFS/SREF OUTPUT ALL SUPPORT NR 100 PCT POPS OVERNIGHT ACROSS ALL OF CENTRAL PA. BEST CHANCE WILL COME BEFORE MIDNIGHT ACROSS THE WESTERN COUNTIES AND AFTER MIDNIGHT ACROSS THE EASTERN COS. SHORT TERM GUIDANCE TIMES THE LOW LEVEL JET EAST OF THE ENTIRE REGION BY 12Z...RESULTING IN THE STEADIEST RAIN EXITING OUR EASTERN COUNTIES ARND DAWN. LOWS IN THE MID 60S TO LOWER 70S WILL FEEL RATHER TROPICAL. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... THE MAIN AXIS OF MOISTURE AND LOW LEVEL FORCING WILL HAVE SHIFTED EAST OF THE AREA BY EARLY TUESDAY...BUT SHORT RANGE OPERATIONAL MODELS SUGGEST THE SURFACE FRONT WILL BE SLOW TO MOVE THROUGH...AND BY AFTERNOON THEY DEVELOP A NOT INSIGNIFICANT AMOUNT OF CAPE AS THE UPPER TROUGH DEEPENS OVERHEAD. EASTERN AREAS ARE PAINTED WITH A MARGINAL THREAT FOR SEVERE TOMORROW...WHICH SEEMS REASONABLE DEPENDING ON THE EVENTUAL PROGRESS OF THE SURFACE BOUNDARY. OTHERWISE THERE WILL BE SCATTERED SHOWERS AND A THREAT FOR THUNDERSTORMS WITH THE BEST CHANCES FAVORING THE EASTERN HALF OF THE FORECAST AREA. HIGHS FROM THE MID 70S TO MID 80S WILL BE SEVERAL DEGREES COOLER THAN NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... BEHIND TUESDAY/S FRONTAL PASSAGE...ANY LINGERING SHOWERS WILL QUICKLY TAPER OFF AS TUESDAY NIGHT PROGRESSES. AN UPPER LEVEL TROUGH WILL DEEPEN OVERHEAD AND COOLER TEMPERATURES WILL MOVE INTO THE REGION FOR WEDNESDAY AND THURSDAY. BOTH THE GEFS AND THE NAEFS CONTINUE TO FORECAST SLIGHTLY BELOW NORMAL 850 MB TEMPERATURES OVER THE FORECAST AREA. ADDITIONALLY...NORTHWEST FLOW ACROSS THE AREA WILL RESULT IN MOUNTAIN SHOWERS WEDNESDAY AFTERNOON AND EVENING. A SURFACE HIGH WILL BUILD SOUTHWEST OF THE AREA ON THURSDAY...BRINGING CLEARER CONDITIONS. THE UPPER LEVEL TROUGH WILL BECOME MORE SHALLOW FRIDAY AS THE SURFACE HIGH PUSHES EAST TOWARDS THE ATLANTIC COAST AND TEMPERATURES WILL BEGIN TO REBOUND UNDER A MORE WESTERLY FLOW. A COLD FRONT WILL MOVE THROUGH FRIDAY AND SATURDAY...BRINGING ANOTHER CHANCE FOR SHOWERS AND AFTERNOON THUNDERSTORMS. THE FRONT PUSHES EAST OF PENNSYLVANIA ON SUNDAY AND DRY CONDITIONS WILL RETURN FOR SUNDAY AND MONDAY. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... AS NOTED BELOW...LOW CLDS OVER MUCH OF THE AREA. HOWEVER...WILL BE WATCHING THE ENTIRE AREA CLOSELY THIS EVENING...AS A STRONG JET AND DRY PUNCH HEAD TOWARD THE AREA. LOW PRESSURE WILL MOVE TOWARD THE LOWER LAKES. PATTERN SUPPORTS STORMS WITH HEAVY RAIN. POTENTIAL FOR SOME STRONG STORMS TOO...ESPECIALLY ACROSS THE WEST LATER THIS EVENING. SOME ADJUSTMENTS MADE TO THE TAFS AT 4 PM. WILL ADJUST MORE HERE FOR THE 21Z TAFS. LOW CIGS OVER MUCH OF THE AREA AT THE CURRENT TIME. EARLIER DISCUSSION BELOW. MARITIME FLOW IN THE LOW LEVELS HAS LED TO A LARGE SHIELD OF LOW CLOUDS HANGING TOUGH OVER MUCH OF THE CENTRAL RIDGE MOUNTAIN AREA...WITH WESTERNMOST TERMINALS JOHNSTOWN AND BRADFORD UNCHARACTERISTICALLY ENJOYING THE BEST CONDITIONS. THE LOW CLOUDS MAY SLOWLY LIFT FOR A TIME FROM ALTOONA THROUGH STATE COLLEGE UP INTO WILLIAMSPORT...BUT IMPROVEMENT WILL LIKELY BE SHORT LIVED WITH CONDITIONS EXPECTED TO DETERIORATE ONCE AGAIN THIS EVENING AND OVERNIGHT AS PRECIPITATION DEVELOPS AND MOVES INTO THE FLYING AREA. THE COLD FRONT WILL MOVE EAST OF THE REGION TUESDAY...WITH A DRIER WESTERLY FLOW EXPECTED TO DEVELOP. THERE WILL STILL BE THE THREAT FOR SCATTERED SHOWERS AND THUNDERSTORMS AS AN UPPER DISTURBANCE CROSSES THE REGION BUT MVFR/IFR EARLY IN THE DAY SHOULD IMPROVE BY AFTERNOON WITH THE DRIER WESTERLY FLOW. OUTLOOK... WED...MOSTLY VFR...SCT SHOWERS WEST. THU-FRI...AM VALLEY FOG POSSIBLE. OTHERWISE...NO SIG WX. FRI-SAT...VFR...SCATTERED SHOWERS. POSSIBLE PM THUNDER. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD/LA CORTE SHORT TERM...LA CORTE LONG TERM...HAGNER AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1254 PM CDT MON AUG 10 2015 .UPDATE... UPDATED TO ADD 18Z AVIATION DISCUSSION. && .PREV DISCUSSION... /ISSUED 1057 AM CDT MON AUG 10 2015/ UPDATE... UPDATED TO TRIM HEAT HEADLINES...UPDATE POPS...AND TEMPERATURES. DISCUSSION... A MESOSCALE CONVECTIVE SYSTEM THAT DEVELOPED OVERNIGHT CONTINUES TO PROGRESS ACROSS THE NORTHERN HALF OF THE FORECAST AREA BUT IS SHOWING A WEAKENING TREND. ALTHOUGH MUCH OF THIS MORNING CONVECTION SHOULD DIMINISH WITHIN THE NEXT FEW HOURS...IT HAS IMPACTED EXPECTED AFTERNOON HIGH TEMPERATURES AND HEAT INDEX VALUES. HEAT INDEX VALUES ABOVE 105 DEGREES SHOULD NOW BE CONFINED TO THE SOUTHERN TIER OF THE MID SOUTH WITH ALL LOCATIONS REMAINING BELOW 110 DEGREES. HEAT HEADLINES HAVE BEEN UPDATED TO REFLECT THIS NEW THINKING...TRIMMING AWAY NORTHERN COUNTIES OF THE ADVISORY AND CANCELING THE EXCESSIVE HEAT WARNING. UPDATED ZONES AND GRIDS HAVE BEEN SENT...WITH THE HWO UPDATED SHORTLY. JLH PREV DISCUSSION... /ISSUED 439 AM CDT MON AUG 10 2015/ A COMPLEX WEATHER DAY ACROSS THE MIDSOUTH. THE UPPER LEVEL RIDGE THAT BROUGHT TRIPLE DIGIT HEAT CLOSE TO THE MIDSOUTH YESTERDAY HAD RETROGRADED OVER THE PAST 12 HOURS...RETURNING NORTHWEST FLOW ALOFT TO THE MIDSOUTH. SEVERAL THUNDERSTORM COMPLEXES HAD FORMED OVER SOUTHERN MO EARLY THIS MORNING...MOVING SOUTHEAST ALONG THE UPPER RIDGE PERIPHERY. ASSUMING THE COLD POOL CAN REMAIN ESTABLISHED THROUGH SUNRISE... 850-500MB THICKNESS FIELDS SUGGEST THESE STORMS WILL MOVE SOUTH/SOUTHEAST THROUGH NORTHEAST AR...WEST TN AND NORTHEAST MS. THE HRRR MODEL HAS BEEN CONSISTENT IN DEPICTING SUCH A SCENARIO. THE AIRMASS FEEDING THESE STORMS WAS RICH WITH MOISTURE...WITH PRECIPITABLE WATER VALUES AROUND 2.25 INCHES. THE LOW LEVEL JET HAS BEEN A RELATIVELY WEAK 20KTS...BUT ADEQUATE TO MAINTAIN STORMS EARLY THIS MORNING. THUNDERSTORM EVOLUTION THROUGH MIDDAY WILL HAVE SIGNIFICANT IMPACTS ON AFTERNOON HEAT INDICES. HAVE TRIMMED BACK HEAT HEADLINES TO REFLECT THE IMPACTS OF THUNDERSTORM OUTFLOW AND INITIAL CLOUD COVER. HEAT INDEX FORECAST CONFIDENCE IS MARGINAL... BUT PERHAPS BEST OVER THE MS RIVER DELTA...FROM CLARKSDALE TO CHARLESTON MS. THIS AREA WILL LEAST LIKELY BE IMPACTED BY THUNDERSTORM OUTFLOW AND CLOUD COVER...AND NEAREST TO THE AFTERNOON LOW LEVEL THERMAL RIDGE OVER SOUTHERN AR AND CENTRAL MS. A WEAK COLD FRONTAL PASSAGE APPEARS ON TRACK FOR LATE THIS EVENING AND EARLY OVERNIGHT. COOLER AND DRIER AIR WILL LAG 12 TO 18 HOURS BEHIND THE INITIAL WIND SHIFT...BUT LIKELY SUFFICIENT TO KEEP TUESDAY AFTERNOON HEAT INDICES BELOW ADVISORY CRITERIA. WEDNESDAY AND THURSDAY SHOULD SEE COOLER AND DRIER CONDITIONS...WITH NORTHERLY WINDS. DAYTIME TEMPS WILL GRADUALLY MODERATE TO NEAR NORMAL VALUES FROM FRIDAY THROUGH NEXT MONDAY...AS THE UPPER RIDGE BUILDS INTO THE MIDDLE MS RIVER VALLEY. RAIN CHANCES FROM MIDWEEK THROUGH EARLY NEXT WEEK APPEAR MINIMAL. PWB && .AVIATION... 18Z TAF CYCLE CONVECTIVE SYSTEM FROM THIS MORNING HAS TEMPORARILY STABILIZED THE ATMOSPHERE. ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT MAY BE POSSIBLE THROUGH EARLY EVENING BUT OVERALL CONFIDENCE REMAINS TOO LOW TO JUSTIFY AT THIS TIME. W/NW WINDS BETWEEN 4-6 KTS WILL BECOME LIGHT/NEARLY CALM TONIGHT AND INCREASE TO 5-8 KTS AFTER 11/15Z. PATCHY FOG MAY PRODUCE MVFR CONDITIONS LATE TONIGHT AT JBR/TUP AND PERHAPS IFR/LIFR CONDITIONS AT MKL. CJC && .MEG WATCHES/WARNINGS/ADVISORIES... AR...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR LEE AR-PHILLIPS. MO...NONE. MS...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR CALHOUN-CHICKASAW- COAHOMA-ITAWAMBA-LAFAYETTE-LEE MS-MONROE-PANOLA-PONTOTOC- QUITMAN-TALLAHATCHIE-TATE-TUNICA-UNION-YALOBUSHA. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS PORTLAND OR
310 PM PDT MON AUG 10 2015 .SYNOPSIS...AN OFFSHORE LOW PRESSURE SYSTEM CENTERED NEAR 45N/130W WILL CONTINUE MOVING SOUTHWARD OFF THE COAST...REACHING WEST OF THE NORTHERN CALIFORNIA COAST TOMORROW AND WEDNESDAY. RESULTING SOUTHERLY FLOW ALOFT IS BRINGING MOISTURE AND INSTABILITY INTO THE REGION AND WILL KEEP SHOWER AND THUNDERSTORM CHANCES AROUND FOR THE NEXT FEW DAYS. THE LOW WILL LIFT OUT TO THE NORTHEAST AND THROUGH THE PACIFIC NORTHWEST ON THURSDAY AND FRIDAY. THE BEST CHANCE OF MORE WIDESPREAD SHOWERS OR THUNDERSTORMS IS LATER THURSDAY INTO FRIDAY AS THE LOW MOVES ONSHORE AND INLAND. WARMER AND DRY WEATHER IS EXPECTED TO RETURN NEXT WEEKEND. && .SHORT TERM...TODAY THROUGH THURSDAY...A SLOW MOVING OFFSHORE CLOSED LOW IS CURRENTLY CENTERED AROUND 45N/130W. AN ASSOCIATED WEAK FRONTAL BOUNDARY HAS BEEN JUST OFFSHORE TODAY...AND EVEN BROUGHT SOME WEAK SHOWERS ONTO THE N OREGON AND S WASHINGTON COAST THIS MORNING. THERE HAVE BEEN SOME DECENT ECHOES ON RADAR INDICATING THAT SOME SHOWERS HAVE BEEN OCCURRING OVER THE COASTAL WATERS FOR MUCH OF THE DAY...BUT DO NOT EXPECT THE FRONT TO HAVE ANY EFFECT ONSHORE GOING FORWARD. THE POSITIONING OF THE UPPER LOW IS RESULTING IN SOUTHERLY FLOW ALOFT OVER THE PAC NW...WHICH IS SPREADING MID LEVEL MOISTURE AND AN UNSTABLE AIR MASS INTO THE REGION. FCST MODEL SOUNDINGS INDICATED A DECENT CAP TO CONVECTION TODAY...BUT IT APPEARS THAT WE HAVE BROKEN THE CAP. SURFACE BASED CONVECTIVE ACTIVITY IS STARTING TO OCCUR ALONG AND EAST OF THE OREGON CASCADE CREST. BASED ON THE LATEST SHORT TERM MODELS...EXPECT THAT THE CONVECTION WILL BECOME MORE VIGOROUS OVER THE NEXT FEW HOURS IN THE CASCADES. SPC MESOSCALE ANALYSIS IS INDICATING 0 TO 6 KM BULK SHEAR VALUES OF AROUND 40 KT OVER THE REGION...WHICH WOULD SUGGEST THAT WE HAVE A BETTER THAN NORMAL CHANCE OF SEEING SOME STRONGER AND LONGER LIVED CELLS FORMING LATER THIS AFTERNOON. SSW FLOW ALOFT SHOULD STEER STORMS INTO THE FOOTHILLS...AND POTENTIALLY INTO THE INTERIOR LOWLANDS AND COAST RANGE LATER THIS AFTERNOON AND THIS EVENING. ALTHOUGH THE CONVECTION TODAY IS SURFACE BASED...A FEW THUNDERSTORMS MAY LINGER INTO THE OVERNIGHT PERIOD AS THERE IS SOME DECENT MID LEVEL INSTABILITY IN PLACE. THERE WILL ALSO BE A WEAK SHORTWAVE MOVING ONSHORE AND WE WILL BE NEAR THE LEFT EXIT REGION OF AN 80 KT JET CORE. THINK THE BEST THUNDER CHANCES OVERNIGHT WILL BE OVER THE CENTRAL OREGON COAST AND COAST RANGE NEAREST TO THE JET EXIT REGION. THEN TOMORROW WILL LIKELY BE A NEAR REPEAT OF TODAY...ASSUMING WE DON/T HAVE TOO MUCH CONVECTIVE DEBRIS CLOUD COVER. THE SOUTHERLY MID LEVEL FLOW IS MODELED TO HAVE A BIT MORE OF AN EASTERLY COMPONENT TO IT...SO THINK THE CHANCES OF GETTING SOME STORMS INTO THE VALLEY AND COAST RANGE WILL BE HIGHER TOMORROW THAN TODAY. THE UPPER LOW WILL BEGIN TO SLOWLY DRIFT NORTHEAST ON WED. EXPECT THAT THERE WILL STILL BE SOME THUNDERSTORM POTENTIAL...GIVEN THAT THE LOW REMAINS TO OUR SW...BUT THE FCST MODELS ARE NOT INDICATING AS MUCH INSTABILITY AND THERE IS NO REAL TRIGGER FOR CONVECTION. SO FOR NOW WILL LIMIT THE THUNDERSTORM CHANCES TO THE CASCADES. THE APPROACH OF THE LOW WILL ALSO START TO INCREASE THE LOW LEVEL ONSHORE FLOW...STARTING A GENERAL COOLING TREND AND INCREASING THE MARINE INFLUENCE OVER THE INTERIOR. THE LOW WILL BEGIN TO PUSH ONSHORE THU. EXPECT THIS WILL BE THE BEST CHANCE FOR MORE WIDESPREAD PRECIPITATION ACROSS THE REGION AS THE COLD POOL ALOFT ASSOCIATED WITH THE LOW CENTER DESTABILIZES THE ATMOSPHERE FURTHER. WILL MAINTAIN A SLIGHT CHANCE FOR THUNDERSTORMS DURING THE DAY THU EAST OF THE COAST RANGE...BUT THINK THE BEST CHANCE WILL BE OVER THE CASCADES. HOWEVER...THERE SHOULD BE QUITE A BIT OF SHOWER ACTIVITY ACROSS THE ENTIRE REGION. THE ONSHORE FLOW WILL STRENGTHEN EVEN MORE THU...LIKELY BRINGING TEMPS OVER THE INTERIOR LOWLANDS DOWN INTO THE UPPER 70S. PYLE .LONG TERM...THE UPPER LEVEL LOW WILL CONTINUE TO MOVE ACROSS THE FORECAST AREA THROUGH FRIDAY. AN INCREASE IN INSTABILITY WILL BRING A GREATER CHANCE OF SHOWERS...WITH A SLIGHT CHANCE OF THUNDERSTORMS EAST OF THE COAST RANGE LATE THURSDAY. THUNDERSTORMS SHOULD BECOME MORE CONFIDED TO THE CASCADES FRIDAY. WIDESPREAD CLOUDS AND MUCH COOLER TEMPERATURES ARE ALSO EXPECTED FRIDAY AS MARINE AIR RETURNS TO THE REGION. MODELS CONTINUE TO SUGGEST DRIER AND SLIGHTLY WARMER WEATHER THROUGH THE WEEKEND...BEFORE ANOTHER TROUGH APPROACHES FROM THE NORTHWEST EARLY NEXT WEEK. HOWEVER...DUE TO DIFFERENCES IN THE MODELS WILL CONTINUE WITH THE CURRENT TREND OF DRYING AND WARMING FOR NOW. /64 && .AVIATION...VFR CONDITIONS CONTINUE ACROSS THE INTERIOR TODAY WITH ONLY SCATTERED MID/HIGH CLOUDS. MEANWHILE VFR CIGS HAVE PERSISTED ALONG THE COAST...WITH LOCAL IFR AROUND KONP...IN THE WEAKLY ONSHORE LOW LEVEL FLOW. WILL SEE ADDITIONAL CUMULUS DEVELOPMENT OVER THE COAST RANGE AND CASCADES THIS AFTERNOON AND ADDITIONAL MID CLOUDS MOVING INTO THE REGION FROM S TO N. HOWEVER...INLAND CIGS SHOULD REMAIN VFR WITH THE POSSIBLE EXCEPTION OF TEMPORARY CIG/VSBY REDUCTIONS IN ANY DEVELOPING SHRA/TSRA. BEST CHANCES REMAIN IN THE 00Z-06Z TIME FRAME. WITH ONSHORE LOW-LEVEL FLOW OVERNIGHT...EXPECT A RETURN OF MARINE STRATUS TO THE COAST AFT 09Z WITH A CHANCE OF A WEAK PUSH ALONG THE COLUMBIA TO AROUND KKLS OR PERHAPS EVEN THE METRO PORTLAND TERMINALS BY AROUND DAYBREAK. KPDX AND APPROACHES...VFR CONTINUES THIS AFTERNOON WITH INCREASING CUMULUS DEVELOPING. MAY SEE ISOLATED TSRA/SHRA FORM...GENERALLY BETWEEN 01Z AND 06Z TUE...BUT BEST CHANCES REMAIN WELL E OF TERMINAL IN CASCADES AND FOOTHILLS. DUE TO THIS CONTINUED LOWER CONFIDENCE...WILL MAINTAIN VCSH IN TAF THROUGH THIS PERIOD AND PROACTIVELY AMEND AS NEEDED. CULLEN && .MARINE...OVERALL NOT MUCH CHANGE TO THE FORECAST THROUGH THE WEEK WITH WINDS AND WAVES REMAINING BELOW ABOUT 15 KTS AND AROUND 4 FT RESPECTIVELY. THE SURFACE LOW CURRENTLY SITS AROUND 250 NM W OF CANNON BEACH AND WILL SLOWLY DRIFT S ACROSS THE REGION THROUGH MIDWEEK. MODELS SUGGEST WINDS WILL BECOME N ON TUE AND BECOME A BIT GUSTY IN THE NORTHERN ZONES. INCREASED FORECAST TO REFLECT GUSTS TO AROUND 20 KT...BUT WILL LET FUTURE SHIFT EVALUATE ANOTHER MODEL RUN TO SEE IF AN ADVISORY MAY BE NEEDED. WINDS THEN RETURN SOUTHERLY ON WED WITH GUSTS 15 TO 20 KT. SURFACE HIGH PRESSURE BUILDS WELL OFFSHORE OVER THE PACIFIC THROUGH THE WEEK AND WILL PUSH INTO THE COASTAL WATERS LATE IN THE WEEK AND ESPECIALLY THIS WEEKEND. THIS WILL BRING A BETTER CHANCE FOR SMALL CRAFT ADVISORY STRENGTH WINDS AS THERMAL LOW PRESSURE STRENGTHENS ALONG THE N CALIFORNIA/S OREGON COAST. CULLEN && .PQR WATCHES/WARNINGS/ADVISORIES... OR...RED FLAG WARNING FROM NOON TODAY TO 11 PM PDT TUESDAY FOR CENTRAL OREGON CASCADE FOOTHILLS-MT. HOOD NATIONAL FOREST WEST OF CASCADE CREST-NORTH OREGON CASCADE FOOTHILLS- WILLAMETTE NATIONAL FOREST. WA...RED FLAG WARNING FROM NOON TODAY TO 11 PM PDT TUESDAY FOR EXTREME SOUTH WASHINGTON CASCADES AND FOOTHILLS. PZ...NONE. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
  [top] Area Forecast Discussion National Weather Service Spokane WA 217 PM PDT MON AUG 10 2015 .SYNOPSIS... Hot weather will return for most of the work week with a continued chance of thunderstorms. Some storms may produce strong winds this afternoon and evening, mainly from the Blue Mountains and Camas Prairie and spreading across extreme eastern Washington and north Idaho. A few record high temperatures may be set Wednesday with a isolated mountain thunderstorms possible. A cold front late Thursday will bring another round of potentially strong thunderstorms. Breezy and cooler conditions are expected by Friday and into the upcoming weekend. && .DISCUSSION... ACTIVE AND UNSETTLED WEATHER EXPECTED THIS WEEK FEATURING HOT CONDITIONS...THUNDERSTORMS AND POTENTIALLY GUSTY WINDS. Tonight through Thursday night...A very active weather period fraught with potential hazards for multiple interested parties is shaping up through the short term. The deep closed upper low pressure visible on satellite circulating off the Oregon coast is the main offender. First...for tonight this low has spawned a short wave disturbance on it`s east flank southerly flow migrating through Oregon this afternoon which is triggering thunderstorms upstream from the forecast area. The pattern for tonight is conducive for these storms to spit out a gust front moving from south to north through the eastern and possibly central Columbia Basin late this afternoon through this evening. This is not a sure bet but the threat is high enough based on previous case histories and supported by some fine scale models to warrant mention of gusty winds and blowing dust across the eastern basin this evening. The unstable moist air mass over the forecast area will also be ripe for lifting by this gust front and the dynamic support from the parent short wave into isolated to scattered thunderstorms across the eastern half of the forecast area tonight...mandating a Red Flag Warning for abundant lightning. Other than the potential evening unpleasantness the late overnight period will be uneventful but warm. Tuesday and Wednesday feature the forecast area stuck under warm southerly flow as the upper low remains largely stationary off the coast. Other than another weak wave marginally detectable on the GFS model due through the panhandle Wednesday morning...thunderstorms will be largely confined to the mountains ringing the Columbia Basin during the afternoons and evenings. The big story of this period will be hot temperatures and sultry overnight lows with generally light and terrain driven winds as a strong surface thermal trough remains entrenched in the basin. Thursday is the next potentially hazardous weather day. Models are in good agreement and consistent in finally ejecting the upper low inland...through the forecast area...Thursday night. After a few days of sweltering temperatures the stage will be set for an outbreak of thunderstorms...not just on the mountains but everywhere...as the trough produces dynamic support aloft and a strong cold front at the surface. These storms will probably begin popping up during the day...isolated in the basin and scattered over the mountains...as the trough approaches. Timing will be critical as far as severe potential is concerned. A late afternoon/evening arrival of the cold front will bear damaging winds...blowing dust haboobs...organized lines of severe thunderstorms and all manner of associated ugliness. A late evening or overnight passage will be less vicious and probably consist of scattered more garden variety thunderstorms and rain showers with localized gusts followed by breezy to windy conditions into Friday morning. This uncertainty forecast will be refined and nailed down in the coming days as the "whites of the eyes" become visible. /Fugazzi Friday through Monday: A change to cooler and drier weather can be expected for the upcoming weekend. After the strong cold front pushes through late Thursday, the upper level low wobbles its way across the northern Cascades and along the Canadian border Friday and Friday night. This feature will enhance convection, continuing the threat of showers with embedded thunderstorms as the cold pool aloft swings through the region. Breezy winds can be expected on Friday with sustained speeds of 15 to 25 mph from the Cascades and across the Columbia Basin with gusts of 30-40 mph. The winds will be in response to the substantial cooling expected Friday by 15 to 20 degrees. After a short heatwave, daytime temperatures Friday will be stuck in the 70s. The upper level low will depart the region by Saturday, leaving a flat ridge dominated by a westerly flow aloft through the weekend with dry conditions and temperatures moderating toward normal. Winds will be lighter but occasional afternoon gusts are possible. The GFS and ECWMF show the flat ridge buckling by Monday as another upper level low drops down from BC and sits along the Canadian border. This will bring another chance of showers to the northern mountains, slightly cooler temperatures and locally breezy winds for Monday. /rfox. && .AVIATION... 18Z TAFS: The timing of the shortwave seems to have slowed a bit by a couple hours and have slowed the time of the convection. Currently high clouds are pushing across the eastern TAF sites, while mostly clear skies found across the Cascades and western Basin. The atmosphere become increasingly unstable at this time with scattered thunderstorms across much of extreme eastern WA and into the ID panhandle. The focus of this thunderstorm activity is expected to remain east of a line from KMWH to KOMK. Primary concerns with thunderstorms will be for strong outflow winds and frequent lightning strikes. Visibility may also be reduced at the TAF sites from blowing, especially at the KGEG, KSFF and KMWH TAF sites. Confidence of thunderstorms this afternoon and evening continues to be moderate. Expect a rapid transition to VFR conditions behind this shortwave overnight into Tues AM. /rfox && .PRELIMINARY POINT TEMPS/POPS... Spokane 64 95 66 99 69 95 / 50 10 20 10 10 20 Coeur d`Alene 59 97 63 98 65 94 / 50 10 20 20 10 20 Pullman 55 97 60 98 63 93 / 60 10 20 10 10 20 Lewiston 65 104 69 105 71 100 / 50 10 20 10 10 30 Colville 60 99 59 102 59 99 / 30 20 10 10 10 20 Sandpoint 54 95 59 97 57 93 / 50 10 20 10 10 20 Kellogg 56 97 60 98 63 93 / 60 10 20 20 10 30 Moses Lake 63 100 64 102 66 96 / 40 10 10 0 0 20 Wenatchee 72 99 70 102 75 93 / 20 10 10 10 0 20 Omak 66 100 66 103 67 98 / 20 20 10 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning until 11 PM PDT this evening for Northern and Central Idaho Panhandle (Zone 101). WA...Red Flag Warning until 11 PM PDT this evening for East Washington Palouse and Spokane Area (Zone 674). Red Flag Warning from 6 PM this evening to 2 AM PDT Tuesday for East Washington South Central Cascade Mountains (Zone 680)- East Washington South Central Cascade Valleys (Zone 676). Red Flag Warning from 6 PM to 11 PM PDT this evening for East Washington Northeast (Zone 686). && $$
Area Forecast Discussion National Weather Service Spokane WA 217 PM PDT MON AUG 10 2015 .SYNOPSIS... Hot weather will return for most of the work week with a continued chance of thunderstorms. Some storms may produce strong winds this afternoon and evening, mainly from the Blue Mountains and Camas Prairie and spreading across extreme eastern Washington and north Idaho. A few record high temperatures may be set Wednesday with a isolated mountain thunderstorms possible. A cold front late Thursday will bring another round of potentially strong thunderstorms. Breezy and cooler conditions are expected by Friday and into the upcoming weekend. && .DISCUSSION... ACTIVE AND UNSETTLED WEATHER EXPECTED THIS WEEK FEATURING HOT CONDITIONS...THUNDERSTORMS AND POTENTIALLY GUSTY WINDS. Tonight through Thursday night...A very active weather period fraught with potential hazards for multiple interested parties is shaping up through the short term. The deep closed upper low pressure visible on satellite circulating off the Oregon coast is the main offender. First...for tonight this low has spawned a short wave disturbance on it`s east flank southerly flow migrating through Oregon this afternoon which is triggering thunderstorms upstream from the forecast area. The pattern for tonight is conducive for these storms to spit out a gust front moving from south to north through the eastern and possibly central Columbia Basin late this afternoon through this evening. This is not a sure bet but the threat is high enough based on previous case histories and supported by some fine scale models to warrant mention of gusty winds and blowing dust across the eastern basin this evening. The unstable moist air mass over the forecast area will also be ripe for lifting by this gust front and the dynamic support from the parent short wave into isolated to scattered thunderstorms across the eastern half of the forecast area tonight...mandating a Red Flag Warning for abundant lightning. Other than the potential evening unpleasantness the late overnight period will be uneventful but warm. Tuesday and Wednesday feature the forecast area stuck under warm southerly flow as the upper low remains largely stationary off the coast. Other than another weak wave marginally detectable on the GFS model due through the panhandle Wednesday morning...thunderstorms will be largely confined to the mountains ringing the Columbia Basin during the afternoons and evenings. The big story of this period will be hot temperatures and sultry overnight lows with generally light and terrain driven winds as a strong surface thermal trough remains entrenched in the basin. Thursday is the next potentially hazardous weather day. Models are in good agreement and consistent in finally ejecting the upper low inland...through the forecast area...Thursday night. After a few days of sweltering temperatures the stage will be set for an outbreak of thunderstorms...not just on the mountains but everywhere...as the trough produces dynamic support aloft and a strong cold front at the surface. These storms will probably begin popping up during the day...isolated in the basin and scattered over the mountains...as the trough approaches. Timing will be critical as far as severe potential is concerned. A late afternoon/evening arrival of the cold front will bear damaging winds...blowing dust haboobs...organized lines of severe thunderstorms and all manner of associated ugliness. A late evening or overnight passage will be less vicious and probably consist of scattered more garden variety thunderstorms and rain showers with localized gusts followed by breezy to windy conditions into Friday morning. This uncertainty forecast will be refined and nailed down in the coming days as the "whites of the eyes" become visible. /Fugazzi Friday through Monday: A change to cooler and drier weather can be expected for the upcoming weekend. After the strong cold front pushes through late Thursday, the upper level low wobbles its way across the northern Cascades and along the Canadian border Friday and Friday night. This feature will enhance convection, continuing the threat of showers with embedded thunderstorms as the cold pool aloft swings through the region. Breezy winds can be expected on Friday with sustained speeds of 15 to 25 mph from the Cascades and across the Columbia Basin with gusts of 30-40 mph. The winds will be in response to the substantial cooling expected Friday by 15 to 20 degrees. After a short heatwave, daytime temperatures Friday will be stuck in the 70s. The upper level low will depart the region by Saturday, leaving a flat ridge dominated by a westerly flow aloft through the weekend with dry conditions and temperatures moderating toward normal. Winds will be lighter but occasional afternoon gusts are possible. The GFS and ECWMF show the flat ridge buckling by Monday as another upper level low drops down from BC and sits along the Canadian border. This will bring another chance of showers to the northern mountains, slightly cooler temperatures and locally breezy winds for Monday. /rfox. && .AVIATION... 18Z TAFS: The timing of the shortwave seems to have slowed a bit by a couple hours and have slowed the time of the convection. Currently high clouds are pushing across the eastern TAF sites, while mostly clear skies found across the Cascades and western Basin. The atmosphere become increasingly unstable at this time with scattered thunderstorms across much of extreme eastern WA and into the ID panhandle. The focus of this thunderstorm activity is expected to remain east of a line from KMWH to KOMK. Primary concerns with thunderstorms will be for strong outflow winds and frequent lightning strikes. Visibility may also be reduced at the TAF sites from blowing, especially at the KGEG, KSFF and KMWH TAF sites. Confidence of thunderstorms this afternoon and evening continues to be moderate. Expect a rapid transition to VFR conditions behind this shortwave overnight into Tues AM. /rfox && .PRELIMINARY POINT TEMPS/POPS... Spokane 64 95 66 99 69 95 / 50 10 20 10 10 20 Coeur d`Alene 59 97 63 98 65 94 / 50 10 20 20 10 20 Pullman 55 97 60 98 63 93 / 60 10 20 10 10 20 Lewiston 65 104 69 105 71 100 / 50 10 20 10 10 30 Colville 60 99 59 102 59 99 / 30 20 10 10 10 20 Sandpoint 54 95 59 97 57 93 / 50 10 20 10 10 20 Kellogg 56 97 60 98 63 93 / 60 10 20 20 10 30 Moses Lake 63 100 64 102 66 96 / 40 10 10 0 0 20 Wenatchee 72 99 70 102 75 93 / 20 10 10 10 0 20 Omak 66 100 66 103 67 98 / 20 20 10 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning until 11 PM PDT this evening for Northern and Central Idaho Panhandle (Zone 101). WA...Red Flag Warning until 11 PM PDT this evening for East Washington Palouse and Spokane Area (Zone 674). Red Flag Warning from 6 PM this evening to 2 AM PDT Tuesday for East Washington South Central Cascade Mountains (Zone 680)- East Washington South Central Cascade Valleys (Zone 676). Red Flag Warning from 6 PM to 11 PM PDT this evening for East Washington Northeast (Zone 686). && $$
Area Forecast Discussion National Weather Service Spokane WA 217 PM PDT MON AUG 10 2015 .SYNOPSIS... Hot weather will return for most of the work week with a continued chance of thunderstorms. Some storms may produce strong winds this afternoon and evening, mainly from the Blue Mountains and Camas Prairie and spreading across extreme eastern Washington and north Idaho. A few record high temperatures may be set Wednesday with a isolated mountain thunderstorms possible. A cold front late Thursday will bring another round of potentially strong thunderstorms. Breezy and cooler conditions are expected by Friday and into the upcoming weekend. && .DISCUSSION... ACTIVE AND UNSETTLED WEATHER EXPECTED THIS WEEK FEATURING HOT CONDITIONS...THUNDERSTORMS AND POTENTIALLY GUSTY WINDS. Tonight through Thursday night...A very active weather period fraught with potential hazards for multiple interested parties is shaping up through the short term. The deep closed upper low pressure visible on satellite circulating off the Oregon coast is the main offender. First...for tonight this low has spawned a short wave disturbance on it`s east flank southerly flow migrating through Oregon this afternoon which is triggering thunderstorms upstream from the forecast area. The pattern for tonight is conducive for these storms to spit out a gust front moving from south to north through the eastern and possibly central Columbia Basin late this afternoon through this evening. This is not a sure bet but the threat is high enough based on previous case histories and supported by some fine scale models to warrant mention of gusty winds and blowing dust across the eastern basin this evening. The unstable moist air mass over the forecast area will also be ripe for lifting by this gust front and the dynamic support from the parent short wave into isolated to scattered thunderstorms across the eastern half of the forecast area tonight...mandating a Red Flag Warning for abundant lightning. Other than the potential evening unpleasantness the late overnight period will be uneventful but warm. Tuesday and Wednesday feature the forecast area stuck under warm southerly flow as the upper low remains largely stationary off the coast. Other than another weak wave marginally detectable on the GFS model due through the panhandle Wednesday morning...thunderstorms will be largely confined to the mountains ringing the Columbia Basin during the afternoons and evenings. The big story of this period will be hot temperatures and sultry overnight lows with generally light and terrain driven winds as a strong surface thermal trough remains entrenched in the basin. Thursday is the next potentially hazardous weather day. Models are in good agreement and consistent in finally ejecting the upper low inland...through the forecast area...Thursday night. After a few days of sweltering temperatures the stage will be set for an outbreak of thunderstorms...not just on the mountains but everywhere...as the trough produces dynamic support aloft and a strong cold front at the surface. These storms will probably begin popping up during the day...isolated in the basin and scattered over the mountains...as the trough approaches. Timing will be critical as far as severe potential is concerned. A late afternoon/evening arrival of the cold front will bear damaging winds...blowing dust haboobs...organized lines of severe thunderstorms and all manner of associated ugliness. A late evening or overnight passage will be less vicious and probably consist of scattered more garden variety thunderstorms and rain showers with localized gusts followed by breezy to windy conditions into Friday morning. This uncertainty forecast will be refined and nailed down in the coming days as the "whites of the eyes" become visible. /Fugazzi Friday through Monday: A change to cooler and drier weather can be expected for the upcoming weekend. After the strong cold front pushes through late Thursday, the upper level low wobbles its way across the northern Cascades and along the Canadian border Friday and Friday night. This feature will enhance convection, continuing the threat of showers with embedded thunderstorms as the cold pool aloft swings through the region. Breezy winds can be expected on Friday with sustained speeds of 15 to 25 mph from the Cascades and across the Columbia Basin with gusts of 30-40 mph. The winds will be in response to the substantial cooling expected Friday by 15 to 20 degrees. After a short heatwave, daytime temperatures Friday will be stuck in the 70s. The upper level low will depart the region by Saturday, leaving a flat ridge dominated by a westerly flow aloft through the weekend with dry conditions and temperatures moderating toward normal. Winds will be lighter but occasional afternoon gusts are possible. The GFS and ECWMF show the flat ridge buckling by Monday as another upper level low drops down from BC and sits along the Canadian border. This will bring another chance of showers to the northern mountains, slightly cooler temperatures and locally breezy winds for Monday. /rfox. && .AVIATION... 18Z TAFS: The timing of the shortwave seems to have slowed a bit by a couple hours and have slowed the time of the convection. Currently high clouds are pushing across the eastern TAF sites, while mostly clear skies found across the Cascades and western Basin. The atmosphere become increasingly unstable at this time with scattered thunderstorms across much of extreme eastern WA and into the ID panhandle. The focus of this thunderstorm activity is expected to remain east of a line from KMWH to KOMK. Primary concerns with thunderstorms will be for strong outflow winds and frequent lightning strikes. Visibility may also be reduced at the TAF sites from blowing, especially at the KGEG, KSFF and KMWH TAF sites. Confidence of thunderstorms this afternoon and evening continues to be moderate. Expect a rapid transition to VFR conditions behind this shortwave overnight into Tues AM. /rfox && .PRELIMINARY POINT TEMPS/POPS... Spokane 64 95 66 99 69 95 / 50 10 20 10 10 20 Coeur d`Alene 59 97 63 98 65 94 / 50 10 20 20 10 20 Pullman 55 97 60 98 63 93 / 60 10 20 10 10 20 Lewiston 65 104 69 105 71 100 / 50 10 20 10 10 30 Colville 60 99 59 102 59 99 / 30 20 10 10 10 20 Sandpoint 54 95 59 97 57 93 / 50 10 20 10 10 20 Kellogg 56 97 60 98 63 93 / 60 10 20 20 10 30 Moses Lake 63 100 64 102 66 96 / 40 10 10 0 0 20 Wenatchee 72 99 70 102 75 93 / 20 10 10 10 0 20 Omak 66 100 66 103 67 98 / 20 20 10 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning until 11 PM PDT this evening for Northern and Central Idaho Panhandle (Zone 101). WA...Red Flag Warning until 11 PM PDT this evening for East Washington Palouse and Spokane Area (Zone 674). Red Flag Warning from 6 PM this evening to 2 AM PDT Tuesday for East Washington South Central Cascade Mountains (Zone 680)- East Washington South Central Cascade Valleys (Zone 676). Red Flag Warning from 6 PM to 11 PM PDT this evening for East Washington Northeast (Zone 686). && $$
Area Forecast Discussion National Weather Service Spokane WA 217 PM PDT MON AUG 10 2015 .SYNOPSIS... Hot weather will return for most of the work week with a continued chance of thunderstorms. Some storms may produce strong winds this afternoon and evening, mainly from the Blue Mountains and Camas Prairie and spreading across extreme eastern Washington and north Idaho. A few record high temperatures may be set Wednesday with a isolated mountain thunderstorms possible. A cold front late Thursday will bring another round of potentially strong thunderstorms. Breezy and cooler conditions are expected by Friday and into the upcoming weekend. && .DISCUSSION... ACTIVE AND UNSETTLED WEATHER EXPECTED THIS WEEK FEATURING HOT CONDITIONS...THUNDERSTORMS AND POTENTIALLY GUSTY WINDS. Tonight through Thursday night...A very active weather period fraught with potential hazards for multiple interested parties is shaping up through the short term. The deep closed upper low pressure visible on satellite circulating off the Oregon coast is the main offender. First...for tonight this low has spawned a short wave disturbance on it`s east flank southerly flow migrating through Oregon this afternoon which is triggering thunderstorms upstream from the forecast area. The pattern for tonight is conducive for these storms to spit out a gust front moving from south to north through the eastern and possibly central Columbia Basin late this afternoon through this evening. This is not a sure bet but the threat is high enough based on previous case histories and supported by some fine scale models to warrant mention of gusty winds and blowing dust across the eastern basin this evening. The unstable moist air mass over the forecast area will also be ripe for lifting by this gust front and the dynamic support from the parent short wave into isolated to scattered thunderstorms across the eastern half of the forecast area tonight...mandating a Red Flag Warning for abundant lightning. Other than the potential evening unpleasantness the late overnight period will be uneventful but warm. Tuesday and Wednesday feature the forecast area stuck under warm southerly flow as the upper low remains largely stationary off the coast. Other than another weak wave marginally detectable on the GFS model due through the panhandle Wednesday morning...thunderstorms will be largely confined to the mountains ringing the Columbia Basin during the afternoons and evenings. The big story of this period will be hot temperatures and sultry overnight lows with generally light and terrain driven winds as a strong surface thermal trough remains entrenched in the basin. Thursday is the next potentially hazardous weather day. Models are in good agreement and consistent in finally ejecting the upper low inland...through the forecast area...Thursday night. After a few days of sweltering temperatures the stage will be set for an outbreak of thunderstorms...not just on the mountains but everywhere...as the trough produces dynamic support aloft and a strong cold front at the surface. These storms will probably begin popping up during the day...isolated in the basin and scattered over the mountains...as the trough approaches. Timing will be critical as far as severe potential is concerned. A late afternoon/evening arrival of the cold front will bear damaging winds...blowing dust haboobs...organized lines of severe thunderstorms and all manner of associated ugliness. A late evening or overnight passage will be less vicious and probably consist of scattered more garden variety thunderstorms and rain showers with localized gusts followed by breezy to windy conditions into Friday morning. This uncertainty forecast will be refined and nailed down in the coming days as the "whites of the eyes" become visible. /Fugazzi Friday through Monday: A change to cooler and drier weather can be expected for the upcoming weekend. After the strong cold front pushes through late Thursday, the upper level low wobbles its way across the northern Cascades and along the Canadian border Friday and Friday night. This feature will enhance convection, continuing the threat of showers with embedded thunderstorms as the cold pool aloft swings through the region. Breezy winds can be expected on Friday with sustained speeds of 15 to 25 mph from the Cascades and across the Columbia Basin with gusts of 30-40 mph. The winds will be in response to the substantial cooling expected Friday by 15 to 20 degrees. After a short heatwave, daytime temperatures Friday will be stuck in the 70s. The upper level low will depart the region by Saturday, leaving a flat ridge dominated by a westerly flow aloft through the weekend with dry conditions and temperatures moderating toward normal. Winds will be lighter but occasional afternoon gusts are possible. The GFS and ECWMF show the flat ridge buckling by Monday as another upper level low drops down from BC and sits along the Canadian border. This will bring another chance of showers to the northern mountains, slightly cooler temperatures and locally breezy winds for Monday. /rfox. && .AVIATION... 18Z TAFS: The timing of the shortwave seems to have slowed a bit by a couple hours and have slowed the time of the convection. Currently high clouds are pushing across the eastern TAF sites, while mostly clear skies found across the Cascades and western Basin. The atmosphere become increasingly unstable at this time with scattered thunderstorms across much of extreme eastern WA and into the ID panhandle. The focus of this thunderstorm activity is expected to remain east of a line from KMWH to KOMK. Primary concerns with thunderstorms will be for strong outflow winds and frequent lightning strikes. Visibility may also be reduced at the TAF sites from blowing, especially at the KGEG, KSFF and KMWH TAF sites. Confidence of thunderstorms this afternoon and evening continues to be moderate. Expect a rapid transition to VFR conditions behind this shortwave overnight into Tues AM. /rfox && .PRELIMINARY POINT TEMPS/POPS... Spokane 64 95 66 99 69 95 / 50 10 20 10 10 20 Coeur d`Alene 59 97 63 98 65 94 / 50 10 20 20 10 20 Pullman 55 97 60 98 63 93 / 60 10 20 10 10 20 Lewiston 65 104 69 105 71 100 / 50 10 20 10 10 30 Colville 60 99 59 102 59 99 / 30 20 10 10 10 20 Sandpoint 54 95 59 97 57 93 / 50 10 20 10 10 20 Kellogg 56 97 60 98 63 93 / 60 10 20 20 10 30 Moses Lake 63 100 64 102 66 96 / 40 10 10 0 0 20 Wenatchee 72 99 70 102 75 93 / 20 10 10 10 0 20 Omak 66 100 66 103 67 98 / 20 20 10 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning until 11 PM PDT this evening for Northern and Central Idaho Panhandle (Zone 101). WA...Red Flag Warning until 11 PM PDT this evening for East Washington Palouse and Spokane Area (Zone 674). Red Flag Warning from 6 PM this evening to 2 AM PDT Tuesday for East Washington South Central Cascade Mountains (Zone 680)- East Washington South Central Cascade Valleys (Zone 676). Red Flag Warning from 6 PM to 11 PM PDT this evening for East Washington Northeast (Zone 686). && $$
Area Forecast Discussion National Weather Service Spokane WA 1223 PM PDT MON AUG 10 2015 .SYNOPSIS... Hot weather will return for most of the work week with a continued chance of thunderstorms. Some storms may produce strong winds this afternoon and evening, mainly from the Blue Mountains and Camas Prairie and spreading across extreme eastern Washington and north Idaho. A few record high temperatures may be set Wednesday with a few mountain thunderstorms possible. A cold front Thursday will bring another active thunderstorm threat along with cooler temperatures by next weekend. && .DISCUSSION... ...LIGHTNING AND GUSTY THUNDERSTORM WINDS POSSIBLE THIS EVENING... The prospect of lightning and gusty thunderstorm outflow late this afternoon and this evening continues to be our primary concern. As of 12 PM, a compact vorticity max in southern Oregon was activating instability over eastern Oregon around Burns and Baker City. Thunderstorms that form over eastern Washington will track north this afternoon and evening. We are uncertain whether these cells will have enough deep layer instability and shear to come off the terrain onto to the Palouse, West Plains and the northern Panhandle. The NAM and several fine resolution convective allowing models (HRRR, RAP and high resolution WRF) do maintain thunderstorms through the evening into the Idaho Panhandle and extreme eastern Washington. The northward extent of thunderstorms may ultimately depend on how organized the clusters become over Oregon this afternoon and whether clusters can produce a cold pool strong enough to sustain northward propagation onto the Palouse and West Plains. The large temperature/dewpoint spreads and steep low level lapse rates suggest the possibility for gusty outflow winds. Will there be enough deep layer shear to produce a "haboob"? That is a tough call. Mid level winds (700-500mb) may not be strong enough to promote a long lived gust front, but the potential for blowing dust is there. /GKoch && .AVIATION... 18Z TAFS: The timing of the shortwave seems to have slowed a bit by a couple hours and have slowed the time of the convection. Currently high clouds are pushing across the eastern TAF sites, while mostly clear skies found across the Cascades and western Basin. The atmosphere become increasingly unstable at this time with scattered thunderstorms across much of extreme eastern WA and into the ID panhandle. The focus of this thunderstorm activity is expected to remain east of a line from KMWH to KOMK. Primary concerns with thunderstorms will be for strong outflow winds and frequent lightning strikes. Visibility may also be reduced at the TAF sites from blowing, especially at the KGEG, KSFF and KMWH TAF sites. Confidence of thunderstorms this afternoon and evening continues to be moderate. Expect a rapid transition to VFR conditions behind this shortwave overnight into Tues AM. /rfox && .PRELIMINARY POINT TEMPS/POPS... Spokane 91 64 97 66 100 69 / 10 40 10 20 10 10 Coeur d`Alene 92 59 97 63 99 65 / 20 40 10 20 20 10 Pullman 90 55 96 60 98 63 / 40 30 10 20 10 10 Lewiston 96 65 102 69 106 71 / 40 30 10 20 10 10 Colville 94 60 99 59 104 59 / 10 30 20 10 10 10 Sandpoint 90 54 95 59 98 57 / 20 30 10 20 10 10 Kellogg 92 56 96 60 98 63 / 30 50 10 20 20 10 Moses Lake 94 63 100 64 103 66 / 10 20 10 10 0 0 Wenatchee 94 72 99 70 102 75 / 10 20 10 10 10 0 Omak 96 66 101 66 102 67 / 0 20 20 10 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning from 2 PM this afternoon to 11 PM PDT this evening for Northern and Central Idaho Panhandle (Zone 101). WA...Red Flag Warning from 2 PM this afternoon to 11 PM PDT this evening for East Washington Palouse and Spokane Area (Zone 674). Red Flag Warning from 6 PM this evening to 2 AM PDT Tuesday for East Washington South Central Cascade Mountains (Zone 680)- East Washington South Central Cascade Valleys (Zone 676). Red Flag Warning from 6 PM to 11 PM PDT this evening for East Washington Northeast (Zone 686). && $$
AREA FORECAST DISCUSSION
NWS SEATTLE WA
900 AM PDT MON AUG 10 2015 .SYNOPSIS...AN UPPER LEVEL LOW WILL SLIDE SOUTH OVER THE OFFSHORE WATERS THROUGH MIDWEEK KEEPING WEATHER GENERALLY WARM WITH PARTLY TO MOSTLY SUNNY SKIES. THERE WILL BE SOME LIGHT SPOTTY SHOWERS MAINLY TUESDAY NIGHT AND WEDNESDAY. THE UPPER LEVEL LOW WILL MOVE BACK TO THE NORTHEAST TOWARD THE AREA THURSDAY AND OVER WESTERN WASHINGTON THURSDAY NIGHT FOR CLOUDIER SKIES...COOLER WEATHER AND A CHANCE OF SHOWERS. && .SHORT TERM...THE UPPER LEVEL LOW OFF THE WASHINGTON COAST HELPING STREAM MID LEVEL CLOUDS ACROSS WESTERN WASHINGTON EARLY THIS MORNING WITH A FEW SHOWERS MOVING NORTH OVER THE AREA THIS MORNING. WENT AHEAD AND UPDATED THE FORECAST FOR THIS MORNING TO REFLECT MORE CLOUDINESS THIS MORNING AND A CHANCE OF SHOWERS MOST AREAS. OTHERWISE SHOWERS SHOULD MOVE NORTH OF THE AREA THIS MORNING LEAVING MID/HIGH LEVEL CLOUDS AT TIMES THROUGH THE AFTERNOON WITH PARTLY SUNNY SKIES. MOSTLY CLOUDY SKIES THIS MORNING WILL INHIBIT THE HIGH TEMPERATURES A BIT TODAY. HOWEVER...SKIES ARE ALREADY CLEARING OVER THE FAR SOUTH THIS MORNING WHICH WILL HELP SOME OF THE WARMER LOCATIONS REACH INTO THE MID 80S TODAY. A WEAK EMBEDDED UPPER LEVEL DISTURBANCE WILL BRUSH THE SOUTHERN PORTION OF THE AREA TONIGHT KEEPING A CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE SOUTH THIS EVENING. THE REMAINDER OF THE AREA WILL REMAIN DRY WITH MID/HIGH LEVEL CLOUDS. WARMER TEMPERATURES ALOFT ON TUESDAY WILL BOOST HIGHS INTO THE 80S WITH SOME LOWER 90S ARE POSSIBLE ESPECIALLY OVER THE SOUTH INTERIOR AND ALONG THE CENTRAL AND SOUTH CASCADE FOOTHILLS. A SECOND WEAK UPPER LEVEL DISTURBANCE WILL BRUSH THE AREA TUESDAY NIGHT FOR ANOTHER CHANCE OF SHOWERS OVER THE AREA. THE UPPER LEVEL LOW OVER THE WASHINGTON OFFSHORE WATERS WILL MOVE TO THE CALIFORNIA OFFSHORE WATERS BEFORE BOUNCING BACK TO THE NORTHEAST ON WEDNESDAY. THE CURRENT FORECAST FOR WEDNESDAY HAS A CHANCE OF SHOWERS WITH PARTLY SUNNY SKIES TO REFLECT THE POTENTIAL FOR EMBEDDED UPPER LEVEL DISTURBANCES AHEAD OF THE MAIN UPPER LEVEL LOW. LOW LEVEL ONSHORE FLOW WILL STRENGTHEN SOMEWHAT RESULTING IN A WEAK PUSH WITH MUCH COOLER HIGH TEMPERATURES ALONG THE COAST AND AROUND 5 DEGREES COOLER THOUGH THE INTERIOR. .LONG TERM...FROM PREVIOUS DISCUSSION...EXTENDED MODELS IN GOOD AGREEMENT ON THE 00Z RUN WITH THE LOW WEAKENING AND MOVING THROUGH WESTERN WASHINGTON THURSDAY NIGHT INTO FRIDAY MORNING WITH THE UPPER LEVEL TROUGH HANGING BACK OVER THE AREA DURING THE DAY ON FRIDAY. WITH THE LOW OVER THE AREA EXPECT CLOUDIER AND COOLER WEATHER WITH SCATTERED SHOWERS. UPPER LEVEL RIDGE BUILDING OVER THE AREA OVER THE WEEKEND WITH THE LOW LEVEL FLOW ONSHORE FOR RETURN TO SUNNY WEATHER WITH TEMPERATURES NEAR OR JUST A LITTLE ABOVE NORMAL. FELTON && .AVIATION...THERE IS AN UPPER LEVEL LOW OFFSHORE WITH SOUTHERLY FLOW ALOFT OVER WASHINGTON. THE AIR MASS IS MOIST AND UNSTABLE THIS MORNING. SOME DRYING AND STABILIZATION IS FORECAST TO OCCUR THIS AFTERNOON. HIGH AND MID LEVEL CLOUDS OVER MOST OF THE AREA WILL CLEAR FROM THE SOUTH. THE COAST ALSO HAS AREAS OF MARINE STRATUS THAT SHOULD LIFT IN THE AFTERNOON. CEILINGS ARE GENERALLY VFR WITH CLOUDS 8-11K FT. THE COAST HAS IFR CEILINGS. CONDITIONS WILL IMPROVE IN THE AFTERNOON. KSEA...SHOWERS MOVING THROUGH THE AREA SHOULD BE GONE BY 18Z AND THERE WILL BE SOME CLEARING. SOUTHERLY WINDS 4-8 KT WILL BECOME NORTHWESTERLY AROUND 00Z. CHB && .MARINE...LIGHT WINDS WILL CONTINUE TONIGHT WITH WEAK PRESSURE GRADIENTS. ONSHORE FLOW WILL INCREASE SOMEWHAT IN THE AFTERNOON BUT WILL KEEP FORECAST WINDS IN THE STRAIT TO WESTERLY 10-20 KT FOR NOW. ONSHORE GRADIENTS WILL INCREASE LATER IN THE WEEK. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...NONE. PZ...NONE. && $$ WWW.WEATHER.GOV/SEATTLE YOU CAN SEE AN ILLUSTRATED VERSION OF THIS DISCUSSION AT WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
Area Forecast Discussion National Weather Service Spokane WA 458 AM PDT MON AUG 10 2015 .SYNOPSIS... Hot weather will return for most of the work week with a continued chance of thunderstorms. Some storms may produce strong winds this afternoon and evening, mainly from the Northeast Blue Mountains and Camas Prairie areas and propagating as far north as the Northeast Mountains and Northern Panhandle. A few record high temperatures may be set Wednesday. A cold front thursday will bring another active thunderstorm threat along with cooler temperatures by next weekend. && .DISCUSSION... ...STRONG WINDS POSSIBLE WITH THUNDERSTORMS TODAY... Today and Tonight: There are a couple of vorticity maximums to watch out for today. Both are swinging around the base of a deep upper level low pressure system off of the coast of WA. The first, and more likely to have the bigger impact, is a shortwave disturbance currently pushing into northern California early this morning. This disturbance is progged to quickly push northeast and begin to push up into the region between noon and 200 PM PDT. Before we do see the effects of this disturbance, we will see some lingering light shower activity mainly across the northern half of the forecast area through this morning. Satellite imagery indicates a lot of clearing occurring behind these showers. This will set up a situation where there should be plenty of sunshine for the atmosphere to destabilize by the afternoon before the disturbance over California makes it this far north. Moisture will increase across the region with dew points expected to remain right around 50 degrees. This will set up the ingredients for a decent amount of surface based CAPE to work with. Models are generally showing somewhere in the neighborhood of 500-1500 J/KG of surface based CAPE across the eastern half of the forecast area; this generally includes areas east of a line extending from Ritzville to Republic. Thunderstorms are expected to initiate over northeast OR and in the southern Panhandle in the early afternoon and the push northward into southeastern WA and into the central Panhandle through the afternoon hours. Main threats with the thunderstorms will be for strong outflow winds. The WRF-NMM, WRF-ARW and HRRR models all show a signal of a gust front emanating northward from the convection. These models have also been consistent with this idea over the past few runs. I increase winds across the Palouse, into the basin, the Spokane- Coeur d`Alene corridor and into the northern mtns and ID Panhandle. These winds may also result in blowing dust with reduced visibility possible across portions of I-90 and highway 2. Forecast confidence in the strong outflow winds and blowing dust is only moderate and there is some bust potential as all the ingredients need to come together. With that said, there is enough evidence that concerns are increasing. Thunderstorms are also expected to include frequent cloud to ground lightning strikes. There will be some rain with the heavier thunderstorm cores, but, away from these course, there will also be a lot of evaporation that takes place. This should result in a higher potential for new fire starts from lightning strikes. The Fire Weather Watch will remain as is for now and will be reassessed later in the morning. A second disturbance will push up more across central OR in the wake of the first. This piece of energy will spark off more thunderstorms that will push northward through the late afternoon hours. These thunderstorms will push into southern WA by the evening, but much of the energy will begin to curl off to the west. This should reduce the amount of forcing that enters the region with this wave and is expected to result in thunderstorms diminishing in intensity by this time. /SVH Tues through Sunday: The Thurs/Fri ejection of the upper trough still looks like the main focus as far as any widespread thunder threat and post- frontal windy wx. The vast majority of model guidance remain similar with digging the upper low S down the Pac Nw coast. The primary challenge will be dealing with the ejection of this low NE into Ern Wa and N Idaho Thurs & Fri. The ECMWF is now only slightly faster to eject this wave NE, and both the GFS and ECMWF continue with the trend of taking the low nearly straight north across Wrn Wa and the Cascades. This would mean the highest threat of thunder would be along and near the Cascades, definitely NOT where we would prefer given the current wildfires that may be enhanced by gusty outflow, not to mention new fire starts. And if this Cascades pcpn is slow to exit, another issue COULD be debris flows on current and recent burns. Though this is the most important part of the fcst, it may not be the most challenging part. As the wave digs S down the coast, Ern Wa and N Idaho will be in a prolonged southerly fetch of increasing moisture within a high- amplitude thermal ridge. This will not only help to destabilize the sfc, but will also complicate matters since there are at least three nocturnal subtle waves that move N into Ern Wa through Wed. All of these accompany weak to moderate convective/potential instability not rooted at the surface that could produce a few overnight lightning strikes. Overnight low temps will be very mild. And within the aforementioned thermal ridge, Spokane may not be the only place that tops record high temps Wed.bz && .AVIATION... 12Z TAFS: A potent shortwave trough of lower pressure will push across the region after 20Z. The atmosphere become increasingly unstable at this time with scattered thunderstorms across much of extreme eastern WA and into the ID panhandle. The focus of this thunderstorm activity is expected to remain east of a line from KMWH to KOMK. Timing of storms at KLWS and KPUW is expected between 20-00Z and between 23-04Z at KGEG, KSFF and KCOE. Primary concerns with thunderstorms will be for strong outflow winds and frequent lightning strikes. Visibility may also be reduced at the TAF sites from blowing, especially at the KGEG, KSFF and KMWH TAF sites. Confidence of thunderstorms this afternoon and evening is moderate. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 91 64 97 66 100 69 / 20 40 10 20 10 10 Coeur d`Alene 92 59 97 63 99 65 / 30 40 10 20 10 10 Pullman 90 55 96 60 98 63 / 40 30 10 20 20 10 Lewiston 96 65 102 69 106 71 / 40 20 20 20 20 10 Colville 94 60 99 59 104 59 / 20 20 10 20 20 20 Sandpoint 90 54 95 59 98 57 / 20 30 10 20 20 20 Kellogg 92 56 96 60 98 63 / 30 50 10 20 10 20 Moses Lake 94 63 100 64 103 66 / 10 20 10 20 10 10 Wenatchee 94 72 99 70 102 75 / 10 30 10 20 20 10 Omak 96 66 101 66 102 67 / 20 30 10 20 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...FIRE Weather Watch from 2 PM PDT this afternoon through late tonight for Northern and Central Idaho Panhandle (Zone 101). WA...FIRE Weather Watch from 2 PM PDT this afternoon through late tonight for East Washington Palouse and Spokane Area (Zone 674). FIRE Weather Watch from this afternoon through late tonight for East Washington South Central Cascade Mountains (Zone 680)- East Washington South Central Cascade Valleys (Zone 676). && $$
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 246 PM CDT MON AUG 10 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DIFFUSE SURFACE COLD FRONT SHIFTING SOUTH OVER SOUTHWEST TO EAST-CENTRAL WISCONSIN EARLY THIS AFTERNOON. BUT BEHIND THE FRONT..INSTABILITY HAS INCREASED TO OVER 800 J/KG ML CAPE AND TEMPERATURES HAVE SURPASSED THE CONVECTIVE TEMP. WEAK CONVERGENCE IS ALSO DEVELOPING ALONG THE BAY AND LAKE BREEZES. SO THINK WILL SEE SCATTERED SHOWERS AND STORMS DEVELOP OVER EASTERN WI FOR THE REST OF THE AFTERNOON. OTHER SHOWERS ARE POPPING UP OVER NORTHEAST MINNESOTA ASSOCIATED WITH A SHORTWAVE TROUGH. THE TAIL END OF THE SHORTWAVE WILL APPROACH FAR N-C WI LATE THIS AFTERNOON OR EARLY THIS EVENING...SO WILL HAVE TO MONITOR FOR A SHOWER ADDITION TO THE FORECAST. FORECAST CONCERNS INCLUDE PRECIP TRENDS...FOLLOWED BY CLOUD AND TEMP TRENDS. TONIGHT...RATHER DIFFUSE SURFACE COLD FRONT WILL SETTLE WELL SOUTH OF THE REGION. BUT THE HIGHER RES MODELS CONTINUE TO POINT TOWARDS WEAK LOW LEVEL CONVERGENCE CONTINUING INTO THE EVENING OVER EASTERN WI...WITH SOME EXTRA UPPER LEVEL SUPPORT ARRIVING VIA THE SHORTWAVE OVER WESTERN ONTARIO. INSTABILITY WEAKENS WITH LOSS OF DAYTIME HEATING...BUT SOME DOES LINGER OVER EAST-CENTRAL WI THROUGH ABOUT MID-EVENING. SO WILL KEEP AN ISOLATED SHOWER MENTION THROUGH ABOUT 03Z. THEREAFTER...SHOULD SEE SOME CLEARING TAKE PLACE OVER CENTRAL AND NORTHEAST WISCONSIN. BUT STRATO-CU FROM NORTHERN MINNESOTA AND ONTARIO WILL MAKE A RUN AT N-C WISCONSIN BY MID TO LATE EVENING. DEWPOINTS WILL GRADUALLY FALL THROUGH THE NIGHT WHICH SHOULD SET UP COOLER NIGHT TIME LOWS. LOWS FROM THE MID 50S NORTH TO LOW 60S SOUTH. TUESDAY...HIGH PRESSURE WILL GRADUALLY BE BUILDING INTO THE REGION. SHOULD SEE PLENTY OF DIURNAL CU POP WITH HEATING OF THE DAY BY LATE MORNING BASED ON UPSTREAM OBS. ANY LOW STRATUS OVER N-C WI SHOULD ALSO TURN INTO A CU FIELD...BUT NO SHOWER ACTIVITY IS EXPECTED. HIGHS RANGING FROM THE LOW 70S NORTH TO AROUND 80 SOUTH. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 246 PM CDT MON AUG 10 2015 MAJOR FEATURE DOMINATING THE CONUS THIS WEEK IS LARGE MID-LEVEL RIDGE OVER THE CENTRAL PLAINS...EXPECTED TO AMPLIFY FURTHER AND DRIFT BACK TOWARDS THE MOUNTAIN WEST. THIS WILL KEEP...AND EVEN ENHANCE NORTHWEST FLOW ALOFT OVER OUR AREA. DESPITE THE NORTHWEST FLOW...THE SHEER AMPLITUDE OF THE RIDGE WILL RESULT IN ABOVE NORMAL HEIGHTS. PAIRED WITH A WEAK 850 MB HIGH OVER THE MIDDLE MISSISSIPPI VALLEY ALLOWING FOR HIGHER TEMPS AT THAT LEVEL...EXPECT HIGHS IN THE SECOND HALF OF THE WEEK TO BE NEAR NORMAL OR ABOVE NORMAL. POTENTIAL FOR PRECIPITATION WILL COME FROM MULTIPLE WEAK TROUGHS RIDING DOWN THE EAST SIDE OF THE RIDGE STRAIGHT INTO THE WEEKEND. A SUBTLE 500 MB VORT MAX LOOKS TO SCOOT NORTHEAST OF THE AREA THROUGH THE UPPER PENINSULA WEDNESDAY AFTERNOON AND EVENING. AT THE TIME...BOTH THE GFS AND EURO SUGGEST ABOUT 1000 J/KG OF CAPE AND ABOUT 30 KNOTS OF SHEAR IN THE MICHIGAN BORDER REGION. BUT...DEEP TEMPERATURE-DEWPOINT SPREADS AND THE LACK OF TRIGGERING MECHANISM MAKE IT DIFFICULT TO SEE CONVECTIVE INITIATION EVEN WITHOUT MUCH CAPPING PRESENT. STILL...BUFKIT TEMPS ARE VERY NEAR THE CONVECTIVE TEMP SO STORMS CAN`T BE RULED OUT IN NORTH CENTRAL AND FAR NORTHEAST WISCONSIN...AND THREW SLIGHT CHANCE POPS IN THERE. PERHAPS MORE SIGNIFICANT PRECIP POTENTIAL COMES THURSDAY INTO FRIDAY...AS A WEAK COLD FRONT WILL CROSS THE REGION. AS WITH WEDNESDAY...THERE APPEARS TO BE MODEST INSTABILITY AND SHEAR FOR SOME STRONG STORMS. AGAIN...LOW LEVEL MOISTURE APPEARS TO BE A LIMITING FACTOR...BUT AT LEAST ON THIS DAY WE HAVE THE FRONT AS A FOCUSING MECHANISM. GIVEN SOME CAPPING PRESENT...THERE`S SIGNIFICANT UNCERTAINTY ABOUT HOW MUCH COVERAGE WILL BE SEEN IN ANY DEVELOPMENT. BUT HAVE HIGHER POPS THAN WEDNESDAY THANKS TO THAT FRONTAL PRESENCE. FINALLY...AFTER A MOSTLY DRY WEEKEND THANKS TO THE UPPER RIDGE TILTING EASTWARD TOWARDS OUR AREA...WE`LL LOOK FOR TROUGHING OVER CANADA TO BEAT DOWN THAT NORTHWARD EXTENT OF THE RIDGE AND PROVIDE ANOTHER SHOT AT SHOWERS AND STORMS LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT ALONG A COLD FRONT. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1158 AM CDT MON AUG 10 2015 A MOISTURE-LADEN AIRMASS WILL BE SLOW TO MOVE OUT BEHIND A WEAK COLD FRONT THIS AFTERNOON. THE HIGH HUMIDITY WILL PRODUCE SCT TO BKN MVFR CONDITIONS AT TIMES...MAINLY OVER EASTERN WISCONSIN. WITH LAKE BREEZE DEVELOPMENT THIS AFTERNOON...EASTERN WISCONSIN COULD ALSO SEE SCT SHOWERS AND ISOLATED TSTORMS POP UP FROM MID- AFTERNOON THROUGH ABOUT MID-EVENING. COOLER AND DRIER AIR WILL FINALLY PUSH INTO THE REGION TONIGHT...AT THE EXPENSE OF LOW STRATUS PUSHING SOUTH INTO N-C WISCONSIN LATE. WITH DAYTIME MIXING...THINK ANY LOW STRATUS WILL BECOME MORE SCATTERED IN NATURE AROUND MIDDAY TUE. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......LUCHS AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
442 PM MDT MON AUG 10 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 242 PM MDT MON AUG 10 2015 WE ARE STARTING TO SEE A FEW BUILDUPS ACROSS THE SOUTHERN LARAMIE RANGE IN WYOMING AS WELL AS IN A ZONE OF DIFFERENTIAL HEATING ON THE NORTH SIDE OF THE NORTH PLATTE RIVER VALLEY ACROSS THE NEBRASKA PANHANDLE NORTH OF SCOTTSBLUFF. DONT THINK MOST STORMS WILL GET OVERLY ROWDY THIS AFTERNOON AND EVENING...ALTHOUGH WITH SBCAPES RUNNING IN THE 1200-1600 J/KG RANGE OVER THE PANHANDLE WE COULD SEE A FEW STRONGER UPDRAFTS TO SUPPORT ISOLATED STRONG/BRIEFLY MARGINALLY SEVERE STORMS...ALTHOUGH TYPICAL OF AUGUST MIDLEVELS ARE FAIRLY WARM. MOST OF THE CONVECTION IS EXPECTED TO FIRE ALONG AND JUST EAST OF THE LARAMIE RANGE THIS AFTERNOON WITH ISOLATED STORMS EXPECTED THROUGH MID EVENING OVER THE PANHANDLE. RATHER AMPLIFIED UPPER RIDGE EXTENDS NORTH ACROSS THE CENTRAL AND NORTHERN ROCKIES WITH OUR FORECAST AREA SEEING A GRADUAL INCREASE IN MIDLEVEL MOISTURE FROM THE SOUTHWEST THROUGH MID WEEK. WILL SEE SCATTERED STORMS TOMORROW AFTERNOON FIRE OVER THE SIERRA MADRE, SNOWY AND SOUTHERN LARAMIE RANGE WITH ISOLATED STORMS EAST ONTO THE PLAINS. BOTH THE GFS AND THE NAM SUPPORT THE NOTION OF A SHORTWAVE RIDING NORTHEAST ACROSS OUR AREA WEDNESDAY AND THAT WILL SUPPORT AN INCREASE IN POPS FOR WEDNESDAY AFTERNOON...ESPECIALLY OUT WEST ALONG AND WEST OF THE LARAMIE RANGE WITH ISOLATED POPS FARTHER EAST. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 242 PM MDT MON AUG 10 2015 FAIRLY STAGNANT PATTERN EXPECTED ACROSS THE CWA WEDS NIGHT INTO SATURDAY WITH A LARGE UPPER RIDGE HOLDING ACROSS THE REGION ATOP AN UPPER HIGH THAT WILL DRIFT SLOWLY WESTWARD ACROSS THE SOUTHERN ROCKY MTNS. TEMPS QUITE WARM THURSDAY THROUGH SATURDAY UNDER A MID LEVEL THERMAL RIDGE WITH 700MB TEMPS WARMING TO ABOUT 14-16C. THIS WILL ALLOW TEMPS TO WARM INTO THE 90S OVER LOWER ELEVATIONS. WEAK IMPULSES WILL DRIFT THROUGH THE UPPER RIDGE AND ACROSS THE REGION AND SHOULD SET OFF ISOLATED CONVECTION FROM TIME TO TIME. INDIVIDUAL WAVES HARD TO TIME SO TAILORED POPS TO FIT WHAT SEEMED TO BE THE BETTER CHANCES. SOME CHANGES MAY ARRIVE IN THE SUNDAY/MONDAY TIME PERIOD AS AN UPPER SHORTWAVE MOVES ACROSS SRN CANADA. THIS SHOULD PUSH A COOL FRONT ACROSS THE CWA EARLY SUNDAY BEFORE WASHING BACK OUT EAST MONDAY. PCPN CHANCE STILL NOT TOO IMPRESSIVE HOWEVER. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 439 PM MDT MON AUG 10 2015 THERE IS THE POSSIBILITY OF LOWER FLIGHT CONDITIONS FOR SOME AIRPORTS IN THE SOUTHERN PANHANDLE AND HERE AT CHEYENNE. LATEST ALTERNATIVE HRRR AND SREF GUIDANCE IS SHOWING KSNY...KCYS AND POSSIBLY KBFF GOING DOWN IN FOG AND STRATUS AFTER 09Z OR SO TUESDAY MORNING. WILL TRY TO NARROW DOWN TIMING AND AIRPORTS ON THE 06Z TAFS. BEST CHANCES LOOK TO BE HERE AT KCYS OVERNIGHT. SOUTHEAST UPSLOPING WINDS TO CONTINUE THROUGH LATE MORNING TUESDAY BEFORE TURNING MORE WESTERLY. && .FIRE WEATHER... ISSUED AT 242 PM MDT MON AUG 10 2015 STILL EXPECTING NO MAJOR FIRE WEATHER CONCERNS THROUGH AT LEAST WEDNESDAY WITH WIND GUSTS (AWAY FROM THUNDERSTORMS) EXPECTED TO REMAIN BELOW 25 MPH AND HUMIDITIES AT OR ABOVE 20 PERCENT FOR MOST LOCATIONS. WE WILL SEE ISOLATED TO SCATTERED THUNDERSTORMS THROUGH MID WEEK IN THE AFTERNOON AND EARLY EVENING HOURS...WITH THE MAIN THREATS FROM THESE BEING CLOUD TO GROUND LIGHTNING AND GUSTY/ERRATIC WINDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...JG LONG TERM...RE AVIATION...GCC FIRE WEATHER...JG
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1120 AM MDT MON AUG 10 2015 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 222 AM MDT MON AUG 10 2015 TRANQUIL WEATHER CONDITIONS TO START THE FORECAST PERIOD WITH MOSTLY CLEAR SKIES IN PLACE ACROSS THE REGION. THERE IS STILL THE POTENTIAL FOR PATCHY FOG TO DEVELOP ALONG AND EAST OF THE LARAMIE RANGE GIVEN WEAK UPSLOPE AND EXCELLENT LOW-LEVEL SATURATION INDICATED BY NAM/GFS BUFKIT SOUNDINGS. THE HRRR HAS NOT BEEN OVERLY SUPPORTIVE...BUT WILL MAINTAIN MENTION OF FOG THROUGH ABOUT 15Z...WHEN BOUNDARY LAYER RHS SHOULD DECREASE. A STALLED N-S ORIENTED COLD FRONT ALONG THE LARAMIE RANGE WILL SUPPORT CONTINUED LOW-LEVEL UPSLOPE TODAY. EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE MOUNTAINS AFTER 21Z...AND MOVE EAST ONTO THE PLAINS THROUGH THE EVENING. CANNOT ENTIRELY RULE OUT A STRONGER STORM OR TWO IF THE GFS VERIFIES WITH SBCAPE NEAR 1000 J/KG ALONG THE I-80 CORRIDOR BETWEEN CYS-SNY...ESPECIALLY GIVEN 0 TO 6 KM SHEAR IN EXCESS OF 35 KTS. SHOULD NOT BE LOOKING AT ANYTHING SEVERE THOUGH. A TYPICAL AUGUST WEATHER PATTERN WILL CONTINUE THROUGH MID WEEK WITH UPPER-LEVEL RIDGING THE DOMINANT FEATURE. SOUTHWEST FLOW ALOFT WILL YIELD A PERSISTENT FEED OF MONSOONAL MOISTURE...GIVING WAY TO DAILY CHANCES FOR CONVECTION GENERALLY ALONG AND WEST OF THE LARAMIE RANGE ON TUESDAY AND WEDNESDAY AFTERNOONS. A GRADUAL WARMING TREND CAN BE EXPECTED AS RIDGING STRENGTHENS...AND H7 TEMPS INCREASE TO NEAR +16 DEG C BY 00Z THU. SHOULD SEE MORE WIDESPREAD 90S FOR AFTERNOON HIGHS BY THE END OF THE PERIOD. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 222 AM MDT MON AUG 10 2015 ALL MEDIUM TO LONG RANGE MODELS SHOW THE UPPER LEVEL HIGH...CENTERED NEAR THE FOUR CORNERS REGION...DOMINATING THE WEATHER PATTERN LATE THIS WEEK AND INTO NEXT WEEKEND. THE HIGH SHOWS SOME SIGNS OF RETROGRADING OR WEAKENING BY NEXT WEEKEND...AS ENERGY FROM THE NORTHERN PACIFIC DIVES SOUTHEAST INTO THE NORTHWEST UNITED STATES. ANY NOTICEABLE CHANGES TO THE PATTERN ARE NOT EXPECTED TO OCCUR OVER THE NEXT 7 DAYS THOUGH...SO EXPECTED PERSISTENT SOUTHWEST FLOW ALOFT AND ADVECTION OF MONSOON MOISTURE LATE THIS WEEK AND NEXT WEEKEND. HIGH TEMPERATURES WILL BE ABOVE NORMAL THROUGH SATURDAY WITH READINGS IN THE 80S TO LOW 90S ACROSS MOST OF THE AREA. PORTIONS OF WESTERN NEBRASKA AND FAR EASTERN WYOMING WILL LIKELY REACH THE MID TO UPPER 90S ON FRIDAY AS 700MB TEMPERATURES PEAK BETWEEN 15C TO 18C. WITH PW/S INCREASING TO OVER ONE INCH ACROSS THE FRONT RANGE...THERE WILL BE PLENTY OF MOISTURE FOR SHOWERS AND TSTORMS TO DEVELOP OVER THE HIGHER TERRAIN. NOT CONFIDENT ON THE COVERAGE AT THIS TIME...BUT SOME OF THESE TSTORMS MAY CONTAIN VERY HEAVY RAINFALL. IN ADDITION...SHOWERS AND TSTORMS WILL NOT MOVE ALL THAT MUCH THROUGH EACH AFTERNOON. THUS THERE IS SOME CONCERN FOR FLASH FLOODING. KEPT POP BETWEEN 20 TO 30 PERCENT FOR THE HIGH VALLEYS AND HIGH PLAINS...WITH VALUES CLOSER TO 50 PERCENT IN THE MOUNTAINS. SEVERE TSTORMS APPEAR UNLIKELY AT THIS TIME DUE TO THE LACK OF SHEAR ACROSS THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING) ISSUED AT 1120 AM MDT MON AUG 10 2015 VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD. ISOLATED SHOWERS A TSTMS POSSIBLE MAINLY OVER THE SE WY MTNS THIS AFTERNOON INTO EARLY THIS EVENING. && .FIRE WEATHER... ISSUED AT 222 AM MDT MON AUG 10 2015 NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. NON-CRITICAL CONDITIONS ARE EXPECTED WITH WIND GUSTS EXPECTED TO REMAIN BELOW 25 MPH AND HUMIDITIES GENERALLY ABOVE 20 PERCENT WITH GOOD TO EXCELLENT RECOVERY OVERNIGHT. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS COULD OCCUR EACH AFTERNOON THROUGH THE WEEK. THE MAIN HAZARD FROM THESE STORMS WILL BE GUSTY AND ERRATIC WINDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CLH LONG TERM...TJT AVIATION...RE FIRE WEATHER...CLH