Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/09/15


AREA FORECAST DISCUSSION
NWS PHOENIX AZ
225 PM MST MON SEP 7 2015 .SYNOPSIS... ISOLATED SHOWERS AND THUNDERSTORM EXPECTED TODAY WITH TEMPERATURES NEAR NORMAL. MOISTURE LEVELS ARE EXPECTED TO INCREASE TUESDAY THROUGH THURSDAY...ESPECIALLY FOR SOUTHEASTERN CALIFORNIA AND THE YUMA VICINITY. BY THE END OF THE WEEK TEMPERATURES WILL BE INCREASING WITH MUCH LOWER CHANCES FOR ANY STORMS. && .DISCUSSION... MOISTURE LEVELS ARE ON THE INCREASE ACROSS THE REGION AS OUTFLOW FROM HURRICANE LINDA OFF THE BAJA CALIFORNIA COAST IS STARTING TO SURGE INTO THE DESERT SOUTHWEST. WATER VAPOR SATELLITE IMAGERY CLEARY SHOWS THE WESTERN EDGE OF THE MOISTURE SURGE AS STRETCHING FROM SOUTHEAST CA UP TO NORTHERN COCONINO COUNTY IN ARIZONA WITH THE MOISTURE PLUME SURGING ALL THE WAY TO THE NORTHEAST INTO UTAH AND COLORADO. SHOWER ACTIVITY IS BUILDING UP ACROSS ARIZONA WITH THE GREATEST ACTIVITY IN YAVAPAI AND COCONINO COUNTIES AT THIS TIME. THE EXTENSIVE CLOUD COVER ACROSS THE GREATER PHOENIX AREA IS HELPING DAMPEN THE TEMPERATURE SOMEWHAT WITH A HIGH SO FAR OF 97 IN PHOENIX TWO HOURS AGO. WEBCAMS AND RADAR INDICATE SOME LIGHT SHOWERS ACROSS THE VALLEY EARLY THIS AFTERNOON. SOME CLEARING IS EVIDENT IN SOUTHWEST MARICOPA COUNTY ON THE VISIBLE SATELLITE IMAGERY AS OF 2 PM AND THIS CLEARING SHOULD REACH THE PHOENIX AREA BY LATE AFTN. MODELS INDICATE THE MOISTURE SURGE WILL CONTINUE THROUGH LATE WEDNESDAY. THE HRRR IN PARTICULAR IN THE SHORT TERM IS DEVELOPING A LINE OF MODERATE RAIN AND THUNDERSTORMS ACROSS NORTHERN YUMA...SOUTHEAST LA PAZ...AND NORTHWEST MARICOPA COUNTY LATER THIS EVENING AS WELL AS MORE ACTIVITY FOR SOUTHERN MARICOPA AND PINAL COUNTIES. HIGH PRESSURE WILL BEGIN TO MOVE BACK OVER THE SOUTHWEST BY FRIDAY SETTLING OVER SOUTHERN NEVADA ...LARGELY CUTTING OFF THE TROPICAL MOISTURE FLOW AND DROPPING CHANCES FOR RAIN AND INCREASING TEMPERATURES FOR THE WEEKEND. && .PREVIOUS DISCUSSION... TODAY AND TUESDAY... SATELLITE AND RADAR DATA EARLY THIS MORNING SHOW DEBRIS CLOUDS WITH SOME EMBEDDED SHOWERS AND EVEN A STRAY THUNDERSTORM DEVELOPING OVER SOUTH-CENTRAL ARIZONA. THE LATEST MODELS HAVE ALL BEEN INDICATING THIS TO VARYING DEGREES. THUS HAVE SLIGHT CHANCE POPS GOING ALL DAY OVER THE LOWER DESERTS OF SOUTH-CENTRAL ARIZONA...THOUGH THICKER CLOUDS WILL LIKELY NOT HANG AROUND ALL DAY. NUDGED FORECAST TEMPS DOWN SLIGHTLY FROM PREVIOUS PACKAGE TO ACCOUNT FOR MORE CLOUD COVER DESPITE THE WESTWARD EXPANSION OF HIGH PRESSURE. SATURATED LAYERS LOOK TO BE EVEN THICKER EAST OF METRO PHOENIX FOR HIGHER POPS THERE...DESPITE LITTLE MODEL CAPE. IN FACT BEST MODEL CAPE FOR OUR FORECAST AREA CONTINUES TO BE OVER SOUTHWEST ARIZONA BUT NOT REALLY LOOKING AT MUCH DIFFERENCE FROM YESTERDAY. THUS POPS REMAIN MODEST TODAY. OVERALL MODELS NOT INDICATING MUCH IMPROVEMENT IN MOISTURE AND CAPE FOR TUESDAY. THOUGH THERE SHOULD BE LESS CLOUDINESS...IT WILL TEND TO BE OFFSET BY THE EXPANDING RIDGE AND ASSOCIATED ANTICYCLONIC FLOW. WEDNESDAY AND THURSDAY... LATEST MODELS ARE INDICATING THAT MOISTURE FROM HURRICANE LINDA WILL MOVE INTO THE AREA WEDNESDAY. LINDA WILL REMAIN OFF THE BAJA COAST BUT WILL BE CLOSE ENOUGH SUCH THAT THERE LOOKS TO BE BOTH A GULF SURGE AND MID AND HIGH CLOUDS MOVING IN. GFS IS MORE AGGRESSIVE WITH THE CLOUDINESS THAN NAM WITH ECMWF IN BETWEEN. THERE MAY BE TOO MUCH CLOUDINESS TO DESTABILIZE ENOUGH FOR FULL FLEDGED THUNDERSTORMS OR EVEN CONVECTIVE SHOWERS...ESPECIALLY IF GFS IS CORRECT. THIS IS REFLECTED IN THE MODEL CIN WHICH REMAINS FAIRLY HIGH. THUS DESPITE THE MOISTURE...POPS REMAIN QUITE MODEST. A CAVEAT IS THAT THERE MAY BE A PERTURBATION IN THE FLOW...AS DEPICTED BY GFS...WHICH CLOUD POSSIBLY AID IN SHOWER DEVELOPMENT. IF ANY CONVECTION MANAGES TO DEVELOP IT WILL BE VERY EFFICIENT AT RAIN PRODUCTION. WITH MORE HUMIDITY AND CLOUDINESS AROUND...HIGH TEMPS WEDNESDAY WILL BE A BIT LOWER...ESPECIALLY OVER SOUTHWEST ARIZONA AND THE LOWER COLORADO RIVER VALLEY. ON THURSDAY...DIFFERENCES BETWEEN GFS AND ECMWF BECOME MORE DISTINCT. ONE KEY AREA IS IN MOISTURE AND CAPE. THE GFS STARTS TRENDING DOWN WHILE THE ECMWF HANGS ON TO HIGHER VALUES...EVEN THOUGH THEY HAVE ROUGHLY SIMILAR POSITIONS FOR THE MAIN ANTICYCLONIC AND CYCLONIC CIRCULATIONS...INCLUDING LINDA. HELD ON TO MODEST POPS AS UPPER LEVEL WEST-NORTHWESTERLY FLOW LOOKS TO BE FAIRLY CONFLUENT. FRIDAY THROUGH SUNDAY... THE FLOW BECOMES MORE AMPLIFIED LATE IN THE WEEK. WITH A NORTHERLY COMPONENT TO THE FLOW...A DRYING TREND IS EXPECTED. NOT SURPRISINGLY THE ECMWF IS MORE RELUCTANT TO DRY THINGS OUT. THE POPS DROP OUT FOR MOST PLACES BY FRIDAY AND EVERYWHERE BY SUNDAY. OF NOTE...AN INVERTED TROUGH IS ADVERTISED TO MOVE THROUGH NEW MEXICO AND ACROSS NORTHWEST MEXICO OVER THE WEEKEND. THE GFS KEEPS IT A BIT FURTHER EAST THAN ECMWF. TAKING A BLENDED APPROACH...AND IN ACKNOWLEDGEMENT OF MUCH OF THE TEMPERATURE GUIDANCE...NUDGED TEMPS DOWN SLIGHTLY FROM PREVIOUS PACKAGE. STILL LOOKING AT TEMPERATURES CLIMBING AT LEAST A FEW DEGREES ABOVE NORMAL...EVEN MORE SO OVER SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... BAND OF SHOWERS WILL CONTINUE TO MOVE NORTH ACROSS THE PHOENIX AREA THIS AFTERNOON...MOST CIGS SHOULD BE ON THE HIGH SIDE...AOA 12K FEET OR SO...WITH SOME HIGH BASED CU IN THE AREA AS WELL. SO FAR IT APPEARS SOMEWHAT STABLE SO THREAT FOR THUNDERSTORMS IS DIMINISHED AND DUE TO LOW CONFIDENCE NO MENTION OF STORMS WILL BE MADE IN THE CURRENT TAF PACKAGE. SHOULD CONVECTION BECOME MORE INTENSE LATER WE CAN UDDATE TAFS FOR THE INCREASED THREAT OF THUNDER. OTHERWISE CONSIDERABLE MID/HIGH CLOUD DECKS EXPECTED THIS EVENING INTO THE MORNING HOURS TOMORROW WITH BROKEN CIGS AOA 14K LIKELY AFTER MIDNIGHT. WINDS GENERALLY LIGHT AND DIURNAL NEXT 24 HOURS. SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... THREAT FOR SHOWERS/STORMS NEXT 24 HOURS QUITE LOW...MOSTLY AOB 10 PERCENT SO NO MENTION WILL BE MADE IN THE TAFS. MOSTLY LOOKING AT SCT TO BKN MID/HIGH LEVEL CLOUD DECKS AT TIMES. WINDS ON THE LIGHT SIDE FAVORING S/SW DIRECTIONS THROUGH TUESDAY AFTERNOON. A FEW STORMS MAY DEVELOP ALONG THE NRN BAJA SPINE AND TRY TO MOVE INTO SWRN IMPERIAL COUNTY BUT CONFIDENCE LOW THAT THEY WILL AFFECT THE KIPL TERMINAL. BETTER CHANCES FOR SHOWERS OR THUNDERSTORMS AS WE MOVE INTO THE MIDDLE OF THE WEEK AS TROPICAL MOISTURE FROM LINDA SPREADS INTO THE AREA FROM THE SOUTH. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... THURSDAY THROUGH MONDAY...SLIGHT THUNDERSTORM CHANCES WILL CONTINUE AREAS-WIDE THURSDAY...TAPERING OFF TO NEARLY NEGLIGIBLE CHANCES BY THE WEEKEND. CONFIDENCE IS HIGHER THAT MOISTURE FROM TROPICAL STORM LINDA WILL SPREAD INTO THE DESERTS FROM THE SOUTH THROUGH MIDWEEK CAUSING AN INCREASE IN STORM CHANCES...AND A MARKED INCREASE IN HUMIDITY LEVELS. MINIMUM RH VALUES WILL MOSTLY RANGE BETWEEN 20 AND 30 PERCENT THURSDAY...LOWERING INTO THE TEENS OVER THE WEEKEND. OVERNIGHT RECOVERIES WILL BE GOOD AT MOST LOCATIONS THROUGH THE PERIOD. NEAR SEASONAL NORMAL HIGH TEMPERATURES THURSDAY WILL CLIMB AND BY THE WEEKEND AS THE AIRMASS DRIES WE CAN EXPECT WELL ABOVE SEASONAL NORMAL READINGS WITH HIGHS REACHING OR EXCEEDING 110 DEGREES OVER THE WESTERN DESERTS OF SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA. WINDS WILL FAVOR A WEST TO SOUTHWEST DIRECTION IN THE AFTERNOON...WITH THE TYPICAL LIGHT DRAINAGE COMPONENT OVERNIGHT. && && .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...WATERS AVIATION...CB FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS TUCSON AZ
1005 AM MST MON SEP 7 2015 .SYNOPSIS...EXPECT SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THROUGH TUESDAY. A DRYING TREND WILL LIKELY BEGIN WEDNESDAY...WITH SHOWERS AND THUNDERSTORMS CONFINED MAINLY NEAR THE EASTERN MOUNTAINS BY THIS WEEKEND. DAYTIME TEMPERATURES WILL GENERALLY BE WITHIN A FEW DEGREES OF NORMAL THIS WEEK. && .DISCUSSION...A FEW SHOWERS AND THUNDERSTORMS WERE OCCURRING ACROSS FAR WESTERN PIMA COUNTY AT THIS TIME. THESE SHOWERS/TSTMS APPEAR TO BE ASSOCIATED WITH A WEAK CYCLONIC CIRCULATION FEATURE OVER THE NRN GULF OF CALIFORNIA. THERE IS ALSO AN AXIS OF INSTABILITY AS PER SPC MESOSCALE ANALYSIS THAT EXTENDS FROM SW ARIZONA SEWD INTO WEST CENTRAL SONORA. A JET STREAK ALSO EXTENDED FROM SOUTH CENTRAL AZ INTO NRN ARIZONA...WITH THE ONGOING CONVECTION ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF THE WEAK JET STREAK. OTHERWISE...MOSTLY SUNNY SKIES PREVAILED ACROSS ERN SECTIONS WITH PARTLY CLOUDY TO CLOUDY SKIES FROM TUCSON WWD INTO WRN PIMA COUNTY. 07/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS 1.56 INCHES. THE SOUNDING DEPICTED A PRONOUNCED WARM LAYER AROUND 400 MB. MODERATE SWLY FLOW CONTINUED ABOVE 500 MB. ADDITIONAL SHOWER/TSTM DEVELOPMENT SHOULD OCCUR DURING THE NEXT 1-2 HOURS WEST OF TUCSON IN RESPONSE TO THE DIAGNOSTIC FEATURES NOTED ABOVE. SEVERAL HRRR SOLUTIONS AND THE 07/12Z WRF-NAM SUGGEST THAT SHOWERS/TSTMS ELSEWHERE WILL BE LIMITED TO MAINLY NEAR THE MOUNTAINS THIS AFTERNOON AND EVENING. THE OFFICIAL FORECAST WAS UPDATED FOR THE ONGOING SHOWERS/TSTMS ACROSS WRN SECTIONS...AND SOME DOWNWARD POP ADJUSTMENTS WERE MADE MOSTLY FOR THE LOWER ELEVATIONS BASED ON THE HRRR AND UNIV OF AZ WRF-NAM SOLUTIONS. AT ANY RATE...ISOLATED TO SCATTERED SHOWERS/TSTMS WILL PREVAIL THIS AFTERNOON/EVENING FOLLOWED BY A SLIGHT CHANCE OF SHOWERS/TSTMS LATE TONIGHT. HIGH TEMPS TODAY WILL BE QUITE CLOSE TO TEMPS ACHIEVED SUN...AND WILL GENERALLY BE WITHIN A FEW DEGS OF NORMAL. PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL. && .AVIATION...VALID THRU 08/18. ISOLATED -TSRA/-SHRA WILL OCCUR WEST OF KTUS THIS MORNING. ISOLATED TO SCATTERED -TSRA/-SHRA WILL THEN OCCUR ELSEWHERE THIS AFTERNOON AND EVENING. ISOLATED -TSRA/-SHRA SHOULD THEN CONTINUE LATE TONIGHT INTO TUESDAY MORNING. OTHERWISE...SCATTERED TO OVERCAST CLOUDS GENERALLY RANGING FROM 10-15K FT AGL AND SURFACE WIND MAINLY LESS THAN 10 KTS WILL PREVAIL INTO TUESDAY MORNING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR THROUGH WEDNESDAY. A DRYING TREND IS THEN EXPECTED TO BEGIN THURSDAY...WITH ISOLATED SHOWERS AND THUNDERSTORMS BECOMING LIMITED TO MAINLY NEAR THE NEW MEXICO BORDER THIS WEEKEND. BRIEF STRONG... GUSTY AND ERRATIC WINDS WILL OCCUR WITH THE STRONGER THUNDERSTORMS. OTHERWISE...20-FOOT WINDS WILL BE MAINLY TERRAIN DRIVEN AND LESS THAN 15 MPH. && .PREV DISCUSSION /320 AM MST/... TUESDAY...LOW LEVEL SURGE OF MOISTURE CONTINUES UP THE GLFCA AS WITH TS LINDA W OF THE SRN TIP OF BAJA. ACROSS SE AZ...PW VALUES REMAIN IN THE 1"-1.50" RANGE WHILE MID-LVL FLOW BECOME A BIT MORE WLY. WILL MAINTAIN SLIGHT CHANCE TO CHANCE TYPE POPS ACROSS THE AREA. WEDNESDAY...LOW LEVEL MOISTURE SURGES INTO THE LOWER DESERTS WITH PW VALUES UP TO AROUND 2" ACROSS SW AZ AND 1.50" ACROSS SE AZ. INCREASED POPS A BIT OUT IN WRN PIMA COUNTY...BUT LATER SHIFTS WILL HAVE TO WATCH MODEL TRENDS FOR WEDNESDAY NIGHT PERIOD. THIS IS BASED ON NEW 06Z NAM RUN WHICH INCREASE ELY FLOW ALOFT OVER THE AREA WED NIGHT INTO THU MORNING WHILE SWINGING A DISTURBANCE IN FROM THE S. CONFIDENCE IN THIS SCENARIO IS ON THE LOW SIDE RIGHT NOW. THURSDAY...UP IN THE AIR AS WEDNESDAY WILL LIKELY DICTATE ON WHAT WILL BE AROUND TO IMPACT STORM DEVELOPMENT. AGAIN CONFIDENCE IS LOW FOR THURSDAY...SO WILL MAINTAIN LOW END TYPE POPS FOR NOW. BASICALLY LOTS OF IFS FOR THE WEDNESDAY/THURSDAY TIME FRAME THUS THE LOW CONFIDENCE IN THE FORECAST. FRIDAY INTO SUNDAY...A SIGNIFICANT DOWNTURN IN STORM CHANCES AS FLOW ALOFT BECOMES MORE NORTHERLY. WILL HOLD ON TO SLIGHT CHANCE POPS FOR THIS TIME FRAME. HIGHS THROUGH MOST OF THIS FORECAST CYCLE WILL REMAIN NEAR NORMAL. HOWEVER WEDNESDAY AND THURSDAY EASILY COULD BE BELOW NORMAL. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1042 PM MDT SUN SEP 6 2015 .UPDATE... ISSUED AT 1042 PM MDT SUN SEP 6 2015 UPPER JET MAX IS INTERACTING WITH MOISTURE AND INSTABILITY ON TOP OF THE EML AND ISOLATED SHOWERS/THUNDER HAVE BEEN POPPING OVER THE NORTHEAST UTAH. HRRR HAS THE BEST HANDLE LATE THIS PM SO WILL RELY ON IT FOR GUIDANCE OVERNIGHT. POPS CHANGED AS A RESULT. && .SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT) ISSUED AT 237 PM MDT SUN SEP 6 2015 ISOLATED SHOWERS AND THUNDERSTORMS HAVE FORMED ACROSS HIGHER TERRAIN AND WITH AVAILABLE MOISTURE STARTING TO DROP...DO NOT EXPECT COVERAGE TO INCREASE TOO MUCH THIS AFTERNOON. DEWPOINTS ARE ABOUT 5 DEGREES LOWER THAN YESTERDAY AND THIS DRYING TREND WILL CONTINUE AS FLOW BECOMES MORE WESTERLY. FOR MOST AREAS THEN...EXPECT SOME CUMULUS BUILDUP...MAYBE A PASSING SHOWER FOR THE HIGHER TERRAIN WITH AN OCCASIONAL RUMBLE OF THUNDER AND SEASONAL TEMPS. MODELS PICKING UP ON A WEAK SHORTWAVE MOVING OVER THE CWA NEAR 3AM KICKING OFF SOME SHOWERS BUT NOT SOLD ON IDEA SO KEPT ANY MENTION OF PRECIP OUT OF FORECAST. LATER SHIFTS CAN REEVALUATE AS NEEDED. WHILE MONDAY WILL REMAIN PREDOMINANTLY DRY...ENOUGH MOISTURE WILL LINGER FOR A FEW LATE DAY SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN. THE UPPER JET WILL WEAKEN THROUGH THE DAY...AND GENERALLY WILL NOT PROVIDE MUCH SUPPORT TO THE AFTERNOON CONVECTION. TEMPERATURES WILL REMAIN NEAR NORMAL FOR EARLY SEPTEMBER...AT MOST A COUPLE DEGREES WARMER THAN TODAY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 237 PM MDT SUN SEP 6 2015 A SHORTWAVE WILL PASS TO OUR NORTH ON TUE...WITH LITTLE IMPACT ON OUR FORECAST AREA. MODELS INDICATE THAT CONVECTIVE ACTIVITY WILL SHIFT TO THE SOUTH AS DRIER AIR MOVES OVER THE NORTH. THE SAN JUANS SHOULD SEE A LITTLE BETTER COVERAGE THAN ON MONDAY. BUT OTHER AREAS WILL EITHER SEE LITTLE CHANGE OR WILL BE DRIER. BY WED THE SUBTROPICAL RIDGE WILL HAVE SHIFTED WESTWARD...INTO THE DESERT SOUTHWEST AND ALONG THE WEST COAST. THIS PUTS OUR FORECAST AREA UNDER A DRIER NORTHWEST FLOW. THE RIDGE WILL CONTINUE TO BUILD OVER THE WEST COAST THROUGH THE WORK WEEK...THEN REMAIN PARKED THERE THROUGH NEXT WEEKEND. THEREFORE LITTLE CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD. TEMPERATURES WILL WARM TO AROUND 5 DEGREES ABOVE NORMAL FOR THE SECOND HALF OF THE WEEK. NIGHTTIME LOWS WILL HOVER AROUND NORMAL IN THE DRY AIR MASS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1042 PM MDT SUN SEP 6 2015 VFR CONDITIONS PREVAIL THE NEXT 24 HOURS AT AREA FORECAST TERMINALS. ISOLATED -SHRA/-TSRA CAN BE EXPECTED IN THE VICINITY OF KVEL/KGJT/KRIL THROUGH SUNRISE...THEN KASE/KEGE/KTEX WILL HAVE A SMALL CHANCE THIS AFTERNOON. OVERALL CONFIDENCE...OUTSIDE OF KVEL THROUGH 07Z...IS LOW AND FORECASTS WILL CONVEY THIS. WILL HAVE TO WATCH USUAL UPVALLEY/NORTHWEST WINDS AT KASE FOR LANDING ISSUES THIS AFTERNOON AS WELL. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...15 SHORT TERM...TGR/EH LONG TERM...EH AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
717 PM EDT TUE SEP 8 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN SOUTH OF NEW ENGLAND THROUGH MID WEEK. HOT AND HUMID CONDITIONS ARE EXPECTED WITH HIGH TEMPERATURES APPROACHING RECORD LEVELS. AN AREA OF LOW PRESSURE WILL LIFT ACROSS THE REGION THURSDAY INTO FRIDAY BRINGING WITH IT THE THREAT OF HEAVY RAIN AND LOCALIZED FLOODING. A LULL FOLLOWS FOR SATURDAY PRIOR TO ANOTHER POTENTIAL BATCH OF RAIN FOR SUNDAY INTO MONDAY. A WARM AND DRY PATTERN LOOKS TO PREVAIL INTO NEXT WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... 730 PM UPDATE... SOME MINOR TWEAKS TO THE FORECAST TO ACCOUNT FOR TRENDS AFTER THIS VERY HOT DAY...THE WARMEST DAY FOR THE ENTIRE SUMMER! A FEW RECORDS ESTABLISHED...WINTER IS NOT THAT VERY FAR AWAY. SOME SHOWER ACTIVITY PERSISTING ALONG THE INITIAL LEADING WAVE OF WHAT LOOKS TO BE PARENT WITH A MID-LEVEL WARM FRONT. LIFTING N/E WITH THE MEAN-LAYER FLOW AS DAYTIME HEATING DIMINISHES...SHOULD SEE THAT SHOWER ACTIVITY CONCLUDE AS THE REGION OF MORE FAVORABLE SHOWER DEVELOPMENT PUSHES ON UP INTO N NEW ENGLAND. ELEVATED INSTABILITY APPARENT COINCIDENT WITH DECENT K-INDICES AS THE PRIOR FORECASTER NOTED. MID-LEVEL DRYING OVERNIGHT APPARENT FROM THE LATEST RAP BUFKIT PROFILES. MOISTURE-POOLING BENEATH THE SUBSEQUENT INVERSION OF HIGH DEWPOINT AIR LENDING TO LOW-CLOUDS / FOG DEVELOPMENT MORE LIKELY OVER SE NEW ENGLAND INCLUDING THE CAPE AND ISLANDS. LATEST SATELLITE SHOWS A BANK OF LOW CLOUDS SITUATED JUST OFFSHORE OF NANTUCKET. WILL BE MONITORING THIS CLOSELY ALONG WITH THE MEAN FLOW. THE CLOUD-BANK MAY NOT NECESSARILY MOVE INTO THE REGION BUT RATHER EXPAND WITH THE INCREASING MOISTURE CONTENT BENEATH THE BUILDING INVERSION. A MILD NIGHT OVERALL WITH DECENT S/SW-FLOW. LOWS AROUND THE MID- TO UPPER-60S WITH WARMEST READINGS AROUND 70-DEGREES FOR THE URBAN CENTERS AND S/SE-SHORES. && .SHORT TERM /WEDNESDAY NIGHT/... WEDNESDAY... MID LEVEL DRY AIR HANGS ON THROUGH THE MORNING BEFORE COLUMN MOISTURE GRADUALLY INCREASES DURING THE AFTERNOON AHEAD OF APPROACHING COLD FRONT. CAPES INCREASE TO ABOUT 1000 J/KG DURING THE AFTERNOON. HI-RES GUIDANCE KEEPS BULK OF CONVECTION TO THE NORTH AND WEST THROUGH THE DAY CLOSER TO THE FRONT...BUT LOW PROB OF A FEW SHOWERS/TSTMS MOVING INTO W MA TOWARD EVENING. ANOTHER HOT AND HUMID DAY...ESPECIALLY ACROSS NE MA AND CT VALLEY WHERE TEMPS WILL LIKELY REACH LOWER 90S AND RECORDS AT BOS/BDL MAY BE APPROACHED. STRONGER SW FLOW AND COOLER 925 MB TEMPS WILL KEEP THE COASTAL PLAIN AND S COAST A BIT COOLER IN THE MID/UPPER 80S. HOWEVER...DEWPOINTS WILL BE CLIMBING INTO THE LOWER 70S NEAR THE S COAST WITH UPPER 60S ELSEWHERE SO QUITE HUMID. WEDNESDAY NIGHT... COLD FRONT MOVES INTO WESTERN NEW ENG DURING THE EVENING AND MAY SEE A FEW SHOWERS/TSTMS HERE DURING THIS TIME. IT APPEARS THE FRONT WILL STALL WEST OF THE I95 CORRIDOR OVERNIGHT AND WILL HAVE TO WATCH FOR RENEWED CONVECTION DEVELOPING ACROSS SE NEW ENG LATE WED NIGHT AHEAD OF THE FRONT AS A PIECE OF INSTABILITY OVER THE OCEAN LIFTS NWD ALONG THE S COAST. MODEST LOW LEVEL JET WILL HAVE MOVED TO THE EAST BY THEN THUS LIMITING LOW LEVEL FORCING AND INSTABILITY IS MARGINAL SO CONFIDENCE IS NOT HIGH. ANY SHOWERS OR TSTMS WILL HAVE POTENTIAL FOR HEAVY RAINFALL AS PWATS INCREASE TO OVER 2 INCHES. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HIGHLIGHTS... * POTENTIAL FOCUSED AREA OF HEAVY RAIN THURSDAY INTO FRIDAY * THREAT OF URBAN / POOR-DRAINAGE FLOODING OVER NEW ENGLAND * A LULL PRIOR TO RENEWED ACTIVITY SUNDAY INTO MONDAY * LOOKING DRY AND WARMER INTO NEXT WEEK DISCUSSION... THURSDAY THROUGH FRIDAY... THERE IS A CONCERN OF A PRONOUNCED AND PROLONGED AREA OF HEAVY RAIN THAT COULD LEAD TO FLOODING. THOUGH SREF PROB AND ENSEMBLE MEMBERS VARY...DETERMINISTIC SOLUTIONS AND POINTS OUTLINED BELOW PROVIDE SOME LEVEL OF ASSURANCE OF AN AREA OF IMPACT ACROSS NEW ENGLAND. KEEPING IN MIND THAT A MAJORITY OF RIVERS AND STREAMS ARE WELL-BELOW NORMAL WITH RESPECT TO STREAMFLOWS AS LAKES AND RESERVOIRS ARE LOW THE SUBSEQUENT FOCUS IS UPON URBAN AND POOR-DRAINAGE FLOODING. MORE DETAILS BELOW. PACIFIC-ORIGIN ENERGY STRETCHED THRU THE E-PERIPHERY OF A DOMINANT GREAT-LAKES TROUGH PATTERN INVOKES AN AREA OF LOW PRESSURE ALONG A QUASI-STATIONARY FRONTAL BOUNDARY OF GREATER BAROCLINICITY SW-NE IN PROXIMITY TO S NEW ENGLAND. LOWERING HEIGHTS PARENT WITH THE RRQ OF THE UPPER-LEVEL JET SITUATED N OF NEW ENGLAND LENDS VENTING-SUPPORT ABOVE DECENT LOW-MID LEVEL CONVERGENCE OF ANOMALOUSLY HIGH THETA-E AIR ALONG AND AHEAD OF THE LOW. AS THE LOW APPROACHES...FOCUS LOOKS FRONTOGENTICAL AROUND H6-8 AS H925-85 THETA-E CONVERGENT NOSE UPSLOPES REARWARD TOWARDS MORE FAVORABLE DIVERGENCE. SQUEEZE OF PWATS IN EXCESS OF 2-INCHES COULD RESULT IN A ROUGHLY SW-NE AREA OF HEAVY RAIN ACROSS NEW ENGLAND. SOME UNCERTAINTY AS TO WHETHER STORMS DEVELOP OUT AHEAD OF THE APPROACHING LOW. FEEL CLOUD COVER ALONG THE FRONTAL BOUNDARY WILL LIMIT DESTABILIZATION. THERE IS ALSO THE THREAT OF A MORNING-PUNCH OF ACTIVITY SHOULD A LOW-LEVEL JET FOCUS CLOSER WITH A CONVERGENT NOSE OF THETA-E BUT ALL INDICATIONS LOOK FOR THIS TO BE OFFSHORE. A LOT OF INTANGIBLES...JUST DOES NOT APPEAR TO BE THE GREATEST SETUP FOR SEVERE ACTIVITY. NEVERTHELESS MARGINAL INSTABILITY YIELDED BY A MOISTENING PROFILE COUPLED WITH SHEAR AROUND OR ABOUT 25 KNOTS IN A CONDITIONALLY-UNSTABLE ENVIRONMENT OF ROUGHLY MOIST-ADIABATIC LAPSE RATES YIELDS A THUNDERSTORM RISK. WILL LEAN WITH A SLIGHT-CHANCE TO CHANCE THREAT OF STORMS WITH THE MARGINALLY UNSTABLE-SHEAR ENVIRONMENT. CAN NOT RULE OUT STRONG ACTIVITY BUT THINK IT WILL BE ISOLATED. MAIN CONCERN AGAIN IS WITH THE HEAVY RAIN AND WILL PREVAIL WITH SUCH WORDING IN THE FORECAST. WILL KEEP WITH HIGH CATEGORICAL POPS AND MODIFY THE HAZARDOUS WEATHER OUTLOOK TO REFLECT THINKING COHESIVELY WITH THIS DISCUSSION. TEMPERATURES NEAR-SEASONABLE. WEEKEND INTO EARLY NEXT WEEK... TIMING / MORPHOLOGY / EVOLUTION OF THE GREAT-LAKES MID-UPPER LEVEL TROUGH DISTURBANCE UNDER SCRUTINY. WILL YIELD TO ENSEMBLE MEANS WITH RESPECT TO OUTCOMES. PARENT SURFACE LOW TO THE DEAMPLIFYING OPEN- WAVE SETUP LOOKS TO LIFT ALONG A FRONTAL BOUNDARY BEING PUSHED OFF- SHORE BY THE WAVE MONDAY. INCREASING RAIN CHANCES SUNDAY WITH THE LOW APPROACH AS THE SURFACE SYNOPTICS LOOK TO COUPLE WITH THE UPPER- LEVEL JET AND DECENT MID-LEVEL FORCING / THETA-E CONVERGENCE. THERE APPEARS TO BE A GOOD CHANCE OF RAIN BUT IT IS POSSIBLE THAT THE SYSTEM AS A WHOLE REMAINS MORE S AND E. WITH UNCERTAINTY / SCRUTINY WILL KEEP WITH CHANCE POPS WITH NEAR-SEASONABLE TEMPERATURES. LOOKS TO BE SOME EMBEDDED THUNDER IN THE MIX WITH THE POTENTIAL THREAT OF HEAVY RAIN TO GO ALONG WITH IT. NEXT WEEK... ENSEMBLE SOLUTIONS SIGNALLING A RETURN TO A RIDGING PATTERN. COULD BE LOOKING AT ANOTHER PRONOUNED HOT-HUMID PERIOD AS HIGH PRESSURE BUILDS S/E OF THE REGION RESULTING IN A PREVAILING SW-FLOW ALOFT. LOW CONFIDENCE IN THE FORECAST AT THIS TIME TILL THE WEEKEND DETAILS BECOME MORE IRONED OUT. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY NIGHT/... 0Z UPDATE... TONIGHT...MODERATE CONFIDENCE. WILL BE A BIT MORE OPTIMISITC. FOCUS OF IFR-LIFR ACROSS S/SE- COASTAL TERMINALS ESPECIALLY ACK. CAN NOT RULE OUT PATCHY FOG DEVELOPMENT ACROSS THE INTERIOR BUT FEEL GREATER LIKELIHOOD IS TOWARDS THE COAST. WEDNESDAY...MODERATE CONFIDENCE. LEFTOVER IFR CIGS/VSBYS SHOULD IMPROVE BY MID MORNING...BUT MAY LINGER INTO THE AFTERNOON OVER ACK. OTHERWISE...VFR. S-SW WIND GUSTS TO 20-25 KT DEVELOPING IN THE COASTAL PLAIN IN THE AFTERNOON. LOW PROB OF A FEW SHOWERS/TSTMS DEVELOPING IN W MA TOWARD EVENING. WEDNESDAY NIGHT...MODERATE CONFIDENCE. AREAS OF IFR/LIFR STRATUS AND PATCHY FOG LIKELY REDEVELOPING OVERNIGHT...ESPECIALLY NEAR THE S COAST. PATCHY FOG ELSEWHERE. SCT SHOWERS/TSTMS POSSIBLE W MA DURING THE EVENING WITH CHANCE OF SHOWERS/TSTMS ELSEWHERE OVERNIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /THURSDAY THROUGH SUNDAY/... THURSDAY INTO FRIDAY...MODERATE CONFIDENCE. A MIX OF LOW-END VFR TO IFR. IFR ESPECIALLY WITH +RA/TSRA FORECAST. S FLOW BACKING N OVER TIME. IMPROVING INTO SATURDAY MORNING. SATURDAY...MODERATE CONFIDENCE. VFR. WINDS VEERING E/SE. SUNDAY...LOW CONFIDENCE. LOW-END VFR TO IFR WITH INCREASING CHANCES OF RAIN. E-WINDS INCREASE THEN BACK W/NW WITH TIME. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE. 730 PM UPDATE...NO MAJOR CHANGES TO THE FORECAST. EXPECT SW FLOW THROUGH THE PERIOD...GUSTING TO 20 KT INTO EARLY EVENING AND AGAIN DURING WEDNESDAY. A FEW HIGHER GUSTS TO 25 KT POSSIBLE WED AFTERNOON/EVENING OVER NEARSHORE S COASTAL WATERS AND A SCA MAY EVENTUALLY BE NEEDED. SEAS REMAIN BELOW 5 FT. OUTLOOK /THURSDAY THROUGH SUNDAY/... THURSDAY INTO FRIDAY...MODERATE CONFIDENCE. LOW PRESSURE PASSING ACROSS S NEW ENGLAND SW TO NE THROUGH THE PERIOD WITH RAIN. EMBEDDED HEAVIER SHOWERS AND THUNDERSTORMS POSSIBLE. ENHANCING S-WINDS AHEAD OF THE LOW COULD GENERATE SEAS IN EXCESS OF 5-FEET ON THE E-WATERS FOR THE LATE THURSDAY INTO FRIDAY PERIOD. WILL SEE IMPROVEMENT INTO SATURDAY MORNING. SATURDAY...MODERATE CONFIDENCE. WINDS VEERING E/SE. GOOD BOATING WEATHER PREVAILS WITH SEAS BELOW 5- FEET. SUNDAY...LOW CONFIDENCE. ANOTHER AREA OF LOW PRESSURE AND RAIN. TRACK UNCERTAIN. COULD SEE IMPACTS ON THE WATERS THOUGH THEY MAY REMAIN MORE S AND E COMPARED TO THURSDAY-FRIDAY. && .CLIMATE... RECORD HIGH TEMPERATURES FOR WEDNESDAY...9/9 BOS...91 IN 1971 PVD...91 IN 1971 ORH...90 IN 1915 BDL...91 IN 2002 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR CTZ002. MA...NONE. RI...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>008. MARINE...NONE. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...KJC/SIPPRELL SHORT TERM...KJC LONG TERM...SIPPRELL AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL CLIMATE...WFO BOX STAFF
AREA FORECAST DISCUSSION
NWS ALBANY NY
125 PM EDT MON SEP 7 2015 .SYNOPSIS... THE HOT WEATHER WILL CONTINUE INTO THE MIDDLE OF THE WEEK WITH INCREASING HUMIDITY LEVELS. HIGH PRESSURE OVER THE REGION WILL SHIFT SOUTH AND EAST OVER THE NEXT FEW DAYS. IN THE MEANTIME...A COLD FRONT WILL GRADUALLY APPROACH FROM THE GREAT LAKES REGION WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS LATER IN THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 125 PM EDT...LABOR DAY HAS FEATURED LOTS OF SUNSHINE AND ABOVE NORMAL TEMPS. HUMIDITY LEVELS ARE STARTING TO CREEP UP TOO WITH SFC DEWPTS RISING IN THE TO LOWER TO M60S. MOST OF THE CLOUD COVER HAS BEEN SOME CIRRUS AND FEW-SCT CUMULUS BY THE MTNS...AS THE CONVECTIVE TEMP ON THE 12Z KALY SOUNDING WAS 91F. THERE IS NOT A STRONG FORCING MECHANISM FOR ISOLD CONVECTION TODAY. THE BEST SHOT FOR ANY DEVELOPMENT WOULD BE FROM A LAKE BREEZE OFF ERIE OR ONTARIO. WE WILL CONTINUE WITH A DRY FCST FOR THE AFTERNOON INTO THE EARLY EVENING WITH THE SFC HIGH OFF THE NEW ENGLAND SEABOARD...AND EXTENDING SW INTO THE MID ATLANTIC CORRIDOR IN CONTROL. THE LATEST HRRR TRENDS ALSO INDICATE A DRY AFTERNOON TOO. HIGH TEMPS WILL BE 10 TO 15 DEGREES ABOVE NORMAL FOR DAY...WITH 80-85F READINGS FOR THE MTNS...AND U80S TO A FEW L90S IN THE VALLEY AREAS. SOME RETOOLING OF THE T/TD/RH/APPARENT TEMPS WERE DONE BASED ON OBSERVATIONS...AND CLOUD COVER BASED ON THE VISIBLE SATELLITE TRENDS. THE WINDS WILL VARY FROM THE SE TO SW AT 5-15 MPH. A WEAK COLD FRONT...OR SFC TROUGH WILL APPROACH FROM THE OVERNIGHT PERIOD INTO TOMORROW. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... FOR TONIGHT EXPECT MILD AND MUGGY CONDITIONS WITH LOWS IN THE MID 60S TO AROUND 70. THE COLD FRONT WILL SLOWLY MOVE FROM THE CENTRAL GREAT LAKES INTO THE EASTERN GREAT LAKES. IT WILL STILL BE MAINLY DRY ACROSS THE FA WITH JUST A SLIGHT CHANCE TO LOW CHANCE OF SHOWERS AND THUNDERSTORMS LATE AT NIGHT ACROSS FAR NORTHWEST PORTIONS OF THE FA. ON TUESDAY THE FRONTAL BOUNDARY WILL BE STALLED ACROSS THE EASTERN GREAT LAKES...SOUTHERN ONTARIO AND SOUTHERN QUEBEC. WHILE MOST OF THE FA WILL BE DRY EXPECT WIDELY SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE NORTHERN HALF OF THE FA. ANY THUNDERSTORM ACTIVITY WILL DIMINISH TUESDAY EVENING WITH ANOTHER WARM AND MUGGY NIGHT. EXPECT HIGHS ON TUESDAY TO BE IN THE MID 80S TO LOWER 90S WITH LOWS TUESDAY NIGHT IN THE MID TO UPPER 60S. FOR WEDNESDAY AND WEDNESDAY NIGHT EXPECT AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS AS THE COLD FRONT MOVES FROM THE EASTERN GREAT LAKES WEDNESDAY MORNING INTO EASTERN NEW YORK AND SOUTHERN VERMONT LATE WEDNESDAY NIGHT. PWATS DURING THIS TIME INCREASE TO 1.75 TO 2+ INCHES...ML MUCAPES INCREASE TO 500 TO 1000 J/KG WITH DEWPOINTS REMAINING MAINLY IN THE 60S. AT THIS TIME NOT EXPECTING THE THUNDERSTORMS TO BE SEVERE. HOWEVER AS WE GET INTO WEDNESDAY AND WEDNESDAY NIGHT HEAVY DOWNPOURS WILL BE POSSIBLE WITH ANY THUNDERSTORMS ESPECIALLY GIVEN THE HIGH PWAT VALUES. HIGHS ON WEDNESDAY ARE EXPECTED TO BE IN THE MID 80S TO AROUND 90 WITH LOWS WEDNESDAY NIGHT IN THE MID TO UPPER 60S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A PATTERN CHANGE WILL BE UNDERWAY DURING THIS TIME PERIOD...AS THE RECENT EASTERN NOAM RIDGE PUSHES FURTHER EAST OFF THE COAST...WHILE AN UPPER LEVEL TROUGH ATTEMPTS TO DEVELOP ACROSS THE NORTHERN PLAINS/UPPER GREAT LAKES REGION. MODELS EXHIBIT CONSIDERABLE UNCERTAINTY AS TO HOW THIS PATTERN CHANGE UNFOLDS...WITH THE 00Z/07 GFS AND GEFS REMAINING MORE PROGRESSIVE WITH THE EVOLVING PATTERN...WHILE THE 00Z/07 ECMWF IS SLOWER AND MUCH MORE AMPLIFIED. THIS DIFFERENCE IS MOST NOTABLE FOR NEXT WEEKEND...AS THE GFS WOULD IMPLY A QUICKER PASSAGE OF THE UPPER LEVEL TROUGH...ALONG WITH SCATTERED RAIN SHOWERS FOR SAT...WHILE THE ECMWF WOULD IMPLY ENERGY HOLDING BACK AND POTENTIALLY CARVING OUT A POSSIBLE CLOSED MID LEVEL LOW CENTER WHICH COULD BRING A POSSIBLE WIDESPREAD STEADY RAINFALL FOR NEXT SUNDAY...ALONG WITH MUCH BELOW NORMAL TEMPS. FOR NOW...HAVE SIDED A BIT CLOSER TO THE GFS/GEFS SIDE FOR CONTINUITY...BUT TRENDS WILL NEED TO BE WATCHED AS WE GET CLOSER TO NEXT WEEKEND. HERE ARE SOME SPECIFICS... THU-THU NT...MOST LONG TERM GUIDANCE SUGGEST THAT THE HIGHEST PROBABILITY OF SHOWERS/THUNDERSTORMS WOULD BE DURING THIS TIME PERIOD AS A POSSIBLE LEAD UPPER LEVEL IMPULSE AND ASSOCIATED COLD FRONT SLOWLY MOVE ACROSS FROM THE WEST/NORTHWEST. THERE COULD BE MULTIPLE WAVES OF LOW PRESSURE ALONG THIS FRONT AS IT MOVES THROUGH. IT APPEARS THAT WIDESPREAD SHOWERS...ALONG WITH SOME EMBEDDED THUNDERSTORMS WILL BE LIKELY THU...WITH SHOWERS PERSISTING INTO THU NT. LOCALLY HEAVY RAINFALL COULD OCCUR...AS PWAT/S POTENTIALLY REACH INTO THE 1.75-2 INCH RANGE. IT SHOULD BE HUMID...WITH MAX TEMPS HELD DOWN TO TO CLOUDS AND SHOWERS...MAINLY IN THE UPPER 70S-LOWER 80S IN VALLEYS...AND LOWER 70S ACROSS HIGHER TERRAIN. SLIGHTLY WARMER TEMPS COULD OCCUR IN SOME LOWER ELEVATIONS SHOULD THE FRONT AND ASSOCIATED CLOUDS/RAIN BE DELAYED. THU NT/FRI AM MINS SHOULD FALL INTO THE LOWER/MID 60S FOR LOWER ELEVATIONS...AND 55-60 ACROSS HIGHER ELEVATIONS. FRI-SAT...SHOWERS MAY BE SLOW TO EXIT ON FRI...ESP FOR AREAS E OF THE HUDSON RIVER...AS THE MID/UPPER LEVEL FLOW REMAINS SOMEWHAT SOUTHWEST WITH THE RIDGE PERSISTING OFF THE EAST COAST. WILL THEREFORE KEEP CHC POPS FOR MOST AREAS IN THE MORNING...THEN DECREASE TO SLIGHT CHC FOR N/W AREAS IN THE AFTERNOON. WILL THEN SIDE CLOSER TO THE GFS/GEFS FOR FRI NT-SAT...KEEPING SLIGHT CHC SHOWERS FRI NT...AND MAINLY CHC POPS FOR SCATTERED SHOWERS SAT AS THE MAIN UPPER TROUGH MOVES THROUGH. EXPECT COOLER TEMPS...WITH FRI AND SAT MAX TEMPS IN THE 70S FOR VALLEYS...AND 60S ACROSS HIGHER TERRAIN...ALTHOUGH SHOULD CLOUDS/SHOWERS LINGER ON FRI...EVEN COOLER TEMPS COULD OCCUR. FRI NT/SAT AM MINS SHOULD FALL INTO THE MID 50S TO LOWER 60S...WARMEST ACROSS THE MID HUDSON VALLEY AND NW CT. SAT NT-SUN...THE 00Z/07 GFS WOULD IMPLY A RETURN TO FAIR WEATHER...WHILE THE 00Z/07 ECMWF WOULD IMPLY CLOUDS AND RAIN RETURNING DURING SUNDAY...ALONG WITH VERY COOL MAX TEMPS...POSSIBLY ONLY REACHING THE 60S IN VALLEYS AND 50S ACROSS HIGHER TERRAIN. AGAIN...HAVE SIDED CLOSER TO THE GFS/GEFS...HOLDING OFF MENTION OF RAIN AT THIS TIME AND WITH WARMER TEMPS COMPARED TO THE ECMWF...WITH MAX TEMPS REACHING THE 60S AND 70S. HOWEVER...AS MENTIONED ABOVE...TRENDS WILL NEED TO BE WATCHED IN CASE UPPER LEVEL ENERGY GETS HELD BACK AND THEN FORMS INTO AN UPPER LEVEL LOW AS SUGGESTED BY THE ECMWF...WHICH WOULD IMPLY A MUCH MORE PESSIMISTIC FORECAST FOR NEXT SUNDAY. && .AVIATION /17Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL SHIFT OFF THE MID ATLANTIC COAST THROUGH TONIGHT. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH LATE TUESDAY. ONLY A FEW CU AND/OR HIGH LEVEL CIRRUS CLOUDS AROUND THIS AFTERNOON AND EVENING. FOR TONIGHT...THERE IS A POSSIBILITY OF PATCHY FOG FORMATION AND MVFR/IFR CONDITIONS AT KPSF AFTER 05Z/TUE...AS SOME WIND MAY KEEP THE BOUNDARY LAYER JUST MIXED ENOUGH TO PREVENT FOG FROM FORMING. ELSEWHERE...ENOUGH OF A BREEZE SHOULD PREVENT MUCH FOG FROM FORMING...WITH VFR CONDITIONS EXPECTED. AFTER 13Z-14Z...ANY FOG SHOULD BURN OFF AND VFR CONDITIONS SHOULD PREVAIL THROUGH TUESDAY MORNING. SOUTH-SOUTHWEST WINDS THIS AFTERNOON AND EVENING AROUND 5-10 KTS. WINDS WILL DECREASE TO LESS THAN 8 KT THIS EVENING AND CONTINUE THROUGH THE NIGHT. SOUTH TO SOUTHWEST WINDS ARE EXPECTED AT LESS THAN 10 KT TUESDAY MORNING. OUTLOOK... MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA. TUE NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. WED: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA. WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. THU NIGHT-FRI: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. && .FIRE WEATHER... THE HOT WEATHER WILL CONTINUE INTO THE MIDDLE OF THE WEEK WITH INCREASING HUMIDITY LEVELS. THE HIGH PRESSURE OVER THE REGION WILL SHIFT SOUTH AND EAST OVER THE NEXT FEW DAYS. IN THE MEANTIME...A COLD FRONT WILL GRADUALLY APPROACH FROM THE GREAT LAKES REGION. RELATIVE HUMIDITIES WILL DROP TO 35 TO 55 PERCENT THIS AFTERNOON...RECOVER TO 80 TO 100 PERCENT TONIGHT...AND DROP TO 35 TO 55 PERCENT TUESDAY AFTERNOON. WINDS WILL BE SOUTHWEST TO WEST AT 5 TO 15 MPH TODAY...SOUTHWEST AT 5 TO 10 MPH TONIGHT AND TUESDAY. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED THE NEXT FEW DAYS. THE RIDGE OF HIGH PRESSURE OVER THE REGION WILL SHIFT SOUTH AND EAST OVER THE NEXT FEW DAYS AS A COLD FRONT GRADUALLY APPROACHES FROM THE GREAT LAKES REGION. MAINLY DRY WEATHER IS EXPECTED UNTIL WEDNESDAY. THE COLD FRONT IS EXPECTED TO MOVE INTO THEN STALL ACROSS THE REGION LATE IN THE WEEK BRINGING MUCH NEEDED RAINFALL TO THE AREA. GUIDANCE INDICATES PWATS SHOULD RISE UP TO ABOUT 2 INCHES AHEAD OF THE BOUNDARY SO HEAVY DOWNPOURS WOULD BE EXPECTED WITH SOME STORMS. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA/WASULA NEAR TERM...WASULA SHORT TERM...11 LONG TERM...KL AVIATION...NAS FIRE WEATHER...IAA/11 HYDROLOGY...IAA/11
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
331 PM EDT MON SEP 7 2015 .DISCUSSION... CURRENTLY/TONIGHT...LATEST HRRR HAS HAD A GOOD HANDLE ON CONVECTIVE DEVELOPMENT THIS AFT WITH SCT-NMRS SHOWER/STORM COVERAGE NEAR THE TREASURE COAST/BREVARD COUNTY TOWARD THE NRN INTERIOR/I-4 CORRIDOR. THIS FOCUS FOR STORMS HAS INITIATED FROM A COMBINATION OF BOUNDARY COLLISIONS AND A MID LEVEL VORT MAX CROSSING THE REGION. THIS CONVECTIVE ACTIVITY WILL CONTINUE TO BUILD NORTHWARD WITH ADDITIONAL DEVELOPMENT POSSIBLE ACROSS THE INTERIOR WHERE SOME BREAKS IN THE HIGHER CLOUD COVER ARE OCCURRING. A FEW STRONGER STORMS WILL CONTINUE INTO LATE AFT/SUNSET WITH FREQUENT LIGHTNING...STRONG WIND GUSTS AND LOCALLY HEAVY RAINFALL POSSIBLE. SOME STORMS HAVE ALSO EXHIBITED ROTATION THIS AFT THAT COULD PRODUCE ISOLATED FUNNEL CLOUDS. MODELS INDICATE DECREASING CONVECTION INTO LATE EVENING AND HAVE RAIN CHANCES ENDING BY MIDNIGHT. LOW LEVEL S/SW FLOW SHOULD KEEP ANY CONVECTION THAT DEVELOPS OVER THE WATERS OFFSHORE OVERNIGHT. LOWS EXPECTED IN THE LOW TO MID 70S. TUE-WED...ABOVE NORMAL RAIN CHANCES CONTINUE TOMORROW AS A MOIST AIRMASS REMAINS IN PLACE WITH LOW PRESSURE OVER THE EASTERN GULF LIFTING SLOWLY NORTHWARD. POPS RANGE FROM 50 PERCENT OVER BREVARD COUNTY/TREASURE COAST UP TO 60-70 PERCENT FARTHER INLAND WHERE BOUNDARY COLLISIONS ARE MORE LIKELY. RAIN CHANCES THEN DECREASE WED AS LOW OVER THE GULF RETROGRADES WEST AND DEEPER RIDGE BUILDS IN FROM THE EAST. DRY MID LEVEL AIR WILL BE DRAWN IN FROM THE SOUTH-SOUTHWEST WITH LATEST ANALYSIS SHOWING 850-500MB MEAN RH VALUES AOB 40PCT. WILL KEEP POPS RANGING FROM 20 PERCENT OVER THE FAR SOUTH TO 30-40 PERCENT NORTH OF OKEECHOBEE COUNTY AND SRN TREASURE COAST. HIGHS WILL INCREASE FROM UPPER 80S TO AROUND 90 DEG TUE TO LOW 90S OVER MUCH OF THE AREA WED. THU-SUN...(PREVIOUS DISCUSSION) H30-H20 JET PATTERN EXPECTED TO AMPLIFY THRU THE LATTER HALF OF THE WEEK AS A 120KT ZONAL JET BTWN THE ALEUTIANS ISLANDS AND THE KAMCHATKA PENINSULA WORKS ITS WAY INTO THE PAC NW. THIS WILL ALLOW A WEAK FRONTAL BOUNDARY EXTENDING FROM THE UPR MID WEST TO THE CENTRAL PLAINS TO DEEP AS IT DRIFTS INTO THE ERN CONUS. THE POSITIVE ORIENTATION OF THE TROF AND THE FACT THAT MOST OF THE JET ENERGY WILL REMAIN WELL N OF THE CANADIAN BORDER SUGGESTS IT WILL NOT BE ABLE TO UPROOT THE ATLC RIDGE FROM ITS POSITION OVER THE FL PENINSULA. HOWEVER...IT WILL KEEP ITS AXIS SUPPRESS OVER THE SRN HALF OF THE PENINSULA...RESULTING INT A DEEP S/SW FLOW PATTERN THRU THE COLUMN. FCST WILL HAVE HIGHER COASTAL POPS TO REFLECT THIS... THOUGH AREAS DOWNWIND OF LAKE OKEECHOBEE MAY SEE DIMINISHED POPS DUE TO THE SHADOW EFFECT. LITTLE CHANGE IN DAY-TO-DAY MAX/MIN TEMPS AS THE S/SWRLY FLOW KEEPS CENTRAL FL UNDER A SULTRY TROPICAL AIRMASS. && .AVIATION...TEMPO IFR/MVFR CONDS WITH GREATER COVERAGE OF SHOWERS AND STORMS NEAR THE BREVARD/TREASURE COASTS AND NRN INTERIOR/I-4 CORRIDOR. STORMS WILL GENERALLY MOVE N/NE BUT NW MOTION ALSO POSSIBLE NORTH OF ORLANDO. SOME THINNING/BREAKS IN THE HIGHER CLOUD COVER OVER THE INTERIOR MAY INITIATE ADDITIONAL SCT SHRA/TSRA THROUGH LATE AFT/SUNSET. DECREASING COVERAGE THEN EXPECTED INTO THE EVENING WITH VFR CONDS RETURNING FOR THE OVERNIGHT PERIOD. && .MARINE... TONIGHT...SE WINDS INCREASE UP TO 10-15 KNOTS OVER THE WATERS...EAST OF WEAK LOW OVER THE EASTERN GULF. SEAS EXPECTED TO INCREASE ONLY SLIGHTLY TO 2-3 FEET. MAIN CONCERN WILL CONTINUE TO BE ANY OFFSHORE MOVING STORMS WITH GUSTY WINDS ALONG THE COAST THROUGH LATE AFT/SUNSET AND SCATTERED STORMS THAT CAN REDEVELOP AND MOVE NORTHWARD OVER THE WATERS OVERNIGHT. TUE-WED...FAVORABLE BOATING CONDITIONS AS THE ATLC RIDGE AXIS REBUILDS ITSELF OVER THE LCL ATLC IN THE WAKE OF THE DEPARTING LOW PRES SYSTEM CURRENTLY OVER THE ERN GOMEX. AXIS POSITIONED OVER THE TREASURE COAST/NRN BAHAMAS SUGGESTS A LIGHT TO GENTLE SRLY FLOW THRU MIDWEEK...BCMG E/SE NEAR THE COAST IN THE AFTN AS THE EAST COAST SEA BREEZE DVLPS. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE. THU-FRI...A FRONTAL TROF OVER THE UPR MIDWEST/CENTRAL PLAINS WILL DRIFT INTO THE ERN CONUS ON THU THEN OFF THE ERN SEABOARD ON FRI. THIS WILL DISPLACE THE ATLC RIDGE TO THE VCNTY OF LAKE OKEECHOBEE... FORCING SFC/BNDRY LYR WINDS TO VEER TO THE S/SW...GENERALLY AOB 10KTS. SEAS 2FT NEARSHORE AND 2-3FT OFFSHORE THRU THE DAY THU...BCMG AOB 2FT AREAWIDE ON FRI && .PRELIMINARY POINT TEMPS/POPS... DAB 75 89 75 91 / 40 60 40 40 MCO 74 89 75 92 / 40 60 30 40 MLB 75 90 76 92 / 40 50 30 30 VRB 74 90 75 91 / 40 50 30 30 LEE 75 89 76 92 / 40 60 20 40 SFB 74 90 76 92 / 40 60 30 40 ORL 75 89 76 92 / 40 60 30 40 FPR 75 91 75 92 / 40 50 30 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ FORECASTS...WEITLICH RADAR/IMPACT WX/AVIATION...KELLY
AREA FORECAST DISCUSSION
NWS MIAMI FL
307 PM EDT MON SEP 7 2015 .SHORT TERM (TONIGHT-WEDNESDAY NIGHT)... A MID LEVEL TROUGH IS CURRENTLY CENTERED OVER THE NORTHEAST GULF OF MEXICO WITH A SURFACE TROUGH EXTENDING FROM NEAR JAX INTO THE SOUTHEAST GULF. THIS IS PROVIDING A DEEP SOUTH-SOUTHWEST FLOW OF TROPICAL AIR INTO SOUTH FLORIDA WITH PWAT JUST OVER 2". THIS ALSO SET THE STAGE FOR EARLY MORNING THUNDERSTORMS MOVING ONSHORE OF THE SOUTHWEST COAST EXPANDING ACROSS THE REMAINDER OF THE PENINSULA INTO EARLY THIS AFTERNOON. AS A RESULT, THE AIRMASS IS STABILIZING OVER THE LAND AREAS AND HAVE THUS REDUCED THE POPS SIGNIFICANTLY MOST AREAS. DUE TO THE PROXIMITY OF THE LOW AND COOL TEMPERATURES ALOFT, CANNOT RULE OUT SOME CONVECTIVE ACTIVITY THROUGH THE NIGHT ALTHOUGH THE HRRR IS NOT SHOWING MUCH AT ALL. BOTH THE GFS AND ECMWF SHOW THE LOW SHIFTING TO THE NORTHWEST ON TUESDAY WITH SOME WARMING AT 500MB AS THE ATLANTIC RIDGE ALSO SHIFTS BACK TO THE WEST. HOWEVER, AS THIS PATTERN ENFOLDS THE LOW LEVELS WILL DESTABILIZE WITH INCREASED DIURNAL HEATING BOTH TUESDAY AND WEDNESDAY. THE FLOW WILL ALSO BACK TO A MORE SOUTH- SOUTHEAST DIRECTION SO A CONTINUATION OF THE TROPICAL FLOW OF AIR AND PWAT REMAINING NEAR 2" SO THE CHANCES OF RAIN WILL BE ELEVATED. THE BACKING STEERING FLOW WILL REVERT THE HIGHEST POPS FROM THE EAST METRO AREA TO MOSTLY THE INTERIOR SO THE GRIDS WILL REFLECT THIS PATTERN SHIFT. .LONG TERM (THURSDAY-MONDAY)... A DEEP LAYER RIDGE WILL BE THE MAIN INFLUENCE ON SOUTH FLORIDA ON THURSDAY AND FRIDAY SO MOSTLY SEA BREEZE INTERACTION TYPE THUNDERSTORM ACTIVITY WILL BE THE PRIMARY PATTERN. OVER THE WEEKEND AND INTO EARLY NEXT WEEK, THE DIURNAL CYCLE WILL LIKELY CONTINUE WITH PWAT HOVERING CLOSE TO OR JUST UNDER 2" BUT THE PATTERN IS A LITTLE UNCERTAIN. BOTH THE GFS AND ECMWF SHOW AN UPSTREAM MID LEVEL TROUGH WEAKENING THE RIDGE ACROSS SOUTH FLORIDA BUT THE ECMWF SHOWS A BROADER TROUGH WITH A DEEP SOUTHWESTERLY FLOW RETURNING. THE GFS ON THE OTHER HAND SHOWS A MORE CLOSED LOW CIRCULATION AND FARTHER TO OUR NORTH KEEPING THE FLOW MOSTLY EASTERLY. FOR NOW, WILL SHOW THE HIGHEST POPS OVER THE INTERIOR AREAS. && .MARINE... A SOUTH TO SOUTHEAST WIND IS EXPECTED THROUGH THE FORECAST PERIOD WITH SEAS OF GENERALLY LESS THAN 4 FEET OUTSIDE OF STRONGER SHOWERS AND THUNDERSTORMS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 78 92 79 92 / 20 40 20 40 FORT LAUDERDALE 79 91 81 91 / 20 40 10 30 MIAMI 78 91 80 92 / 20 40 10 30 NAPLES 77 91 77 91 / 30 50 10 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...30/KOB LONG TERM....30/KOB
AREA FORECAST DISCUSSION
NWS MIAMI FL
142 PM EDT MON SEP 7 2015 .AVIATION... CONVECTION IS SLOWING DOWN THIS AFTERNOON. THIS IS IN AGREEMENT WITH THE SHORT RANGE HRRR MODEL. THERE IS A POTENTIAL FOR ADDITIONAL CONVECTION THIS AFTERNOON, SO, HAVE A TEMPO FOR A COUPLE HOURS LONGER, AND VCTS FOR MOST OF THE AFTERNOON, ALTHOUGH BACKED UP THE CUTOFF TIME BY AN HOUR. DUE TO THE CONVECTION, THE WINDS HAVE BEEN ERRATIC, AND MAY CONTINUE TO BE SO UNTIL AFTER ALL THE CONVECTION WINDS DOWN. OTHERWISE, MAINLY VFR CONDITIONS ACROSS SOUTH FLORIDA, EXCEPT UNDER HEAVY SHOWERS AND THUNDERSTORMS. && .PREV DISCUSSION... /ISSUED 858 AM EDT MON SEP 7 2015/ UPDATE... LATEST UPDATE CONTAINS MINOR TWEAKS TO MAINLY THE WIND AND SKY ELEMENTS. THERE ARE SOME LARGER ADJUSTMENTS TO THE POPS ALONG THE GULF COAST, WHERE A LINE OF SHOWERS AND THUNDERSTORMS ARE MOVING ONSHORE. AVIATION... WITH A WEAK LOW, CENTERED JUST TO THE NORTHWEST, THE FLOW WILL CONTINUE TO BE SOUTH TO SOUTHEASTERLY. THIS SHOULD HELP TO PUSH SOME OF THE SHOWERS AND THUNDERSTORMS A LITTLE FURTHER INLAND THAN YESTERDAY. HOWEVER, THERE IS STILL A CHANCE THEY CAN IMPACT THE TAF SITES, MAINLY IN THE AFTERNOON HOURS. VFR WILL BE THE PREDOMINATE FORECAST, HOWEVER, BRIEF IFR IS POSSIBLE UNDER HEAVY SHOWERS AND THUNDERSTORMS. PREV DISCUSSION... /ISSUED 316 AM EDT MON SEP 7 2015/ .LATE SUMMER TIME WEATHER PATTERN SETTING UP OVER SOUTH FLORIDA THIS WEEK... SHORT TERM... A MID TO UPPER LEVEL LOW OVER THE NORTHEAST GULF OF MEXICO WILL MOVE SLOWLY WEST INTO THE NORTHERN CENTRAL GULF OF MEXICO TODAY...AS HIGH PRESSURE REMAINS OVER THE WESTERN ATLANTIC WATERS. THIS WILL KEEP A SOUTHERLY WIND FLOW OVER SOUTH FLORIDA TODAY FOCUSING THE SHOWERS AND THUNDERSTORMS OVER THE NORTHERN AREAS. HOWEVER...ALL OF SOUTH FLORIDA WILL SEE AT LEAST SCATTERED POPS TODAY. THE MID TO UPPER LEVEL LOW WILL CONTINUE TO RETROGRADE WESTWARD WHILE WEAKENING INTO THE WESTERN GULF OF MEXICO INTO WEDNESDAY...AS HIGH PRESSURE OVER THE WESTERN ATLANTIC WATERS BUILDS WESTWARD INTO THE FLORIDA PENINSULA. THIS WILL ALLOW FOR THE WIND FLOW TO BECOME EASTERLY OVER SOUTH FLORIDA AND BRING IN SOME DRIER AIR TO THE AREA. THEREFORE...THE HIGHEST POPS WILL SHIFT TO THE WESTERN AREAS OF SOUTH FLORIDA FOR THE MIDDLE PART OF THE WEEK. LONG TERM... THE HIGH WILL REMAIN OVER THE FLORIDA PENINSULA LATE THIS WEEK AND INTO NEXT WEEKEND...KEEPING THE EASTERLY WIND FLOW OVER SOUTH FLORIDA. THIS WILL KEEP THE HIGHEST POPS OVER THE WESTERN AREAS OF SOUTH FLORIDA WITH ONLY ISOLATED TO LOW END SCATTERED POPS OVER THE EASTERN AREAS OF SOUTH FLORIDA. AVIATION... THE WINDS WILL BE SOUTHERLY LESS THAN 5 KNOTS THIS MORNING OVER THE EAST COAST TAF SITES...BEFORE SWINGING TO A SOUTH SOUTHEAST DIRECTION AT 5 TO 10 KNOTS THIS AFTERNOON. FOR KAPF TAF SITE...THE WINDS WILL BE LIGHT AND VARIABLE EARLY THIS MORNING BEFORE BECOMING WESTERLY AT 5 TO 10 KNOTS THIS MORNING INTO THIS AFTERNOON. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER ALL OF THE TAF SITES AFTER 16Z TODAY. THEREFORE...VCTS WILL REMAIN IN ALL OF SOUTH FLORIDA TAF SITES FOR THIS AFTERNOON. THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS AT THIS TIME...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS AFFECTING THE TAF SITES. HOWEVER...THE CEILING AND VIS SHOULD FALL INTO THE MVFR OR EVEN IFR CONDITIONS WHEN A SHOWER OR THUNDERSTORM MOVES OVER THE TAF SITE. MARINE... THE WINDS WILL BE SOUTHERLY AT 5 TO 10 KNOTS TODAY BEFORE BACKING TO AN EAST TO SOUTHEAST DIRECTION TONIGHT THROUGH THE REST OF THIS WEEK. THIS WILL KEEP THE SEAS AT 2 FEET OR LESS IN BOTH THE ATLANTIC AND GULF WATERS OF SOUTH FLORIDA THROUGH THIS WEEK. THEREFORE...BOATING CONDITIONS SHOULD BE GOOD OUTSIDE OF ANY SHOWERS OR THUNDERSTORMS THIS WEEK OVER SOUTH FLORIDA WATERS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 78 92 79 92 / 40 40 20 20 FORT LAUDERDALE 80 91 81 91 / 30 30 20 20 MIAMI 79 92 80 92 / 20 40 20 20 NAPLES 77 91 77 91 / 20 30 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...13/SI LONG TERM....54/BNB AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
801 PM EDT TUE SEP 8 2015 .SYNOPSIS... HIGH PRESSURE IN THE ATLANTIC WILL CIRCULATE A MOIST SOUTH FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A WEAK SURFACE TROUGH WILL ALSO BE NEAR THE AREA. THE PATTERN WILL SUPPORT A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY NEAR THE TIMES OF MAXIMUM HEATING. DRIER AIR WILL BEGIN TO FILTER INTO THE REGION BY THE BEGINNING OF NEXT WEEK BEHIND A COLD FRONT THAT WILL PUSH THROUGH OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AIR MASS WEAKLY UNSTABLE THIS EVENING. SHOWERS AND THUNDERSTORMS ISOLATED. LATEST RADAR AND SATELLITE TRENDS SUGGEST WEAKENING TREND. HRRR IN AGREEMENT. WILL CUT POPS BACK. STRATUS EXPECTED LATE TONIGHT. PATCHY FOG ALSO POSSIBLE. LEANED TOWARD THE WARMER LOW TEMPERATURE GUIDANCE BECAUSE OF THE DEEP MOISTURE WITH LOWS IN THE LOWER 70S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... MODELS REMAIN IN GOOD AGREEMENT THROUGH THIS TIME PERIOD. UPPER PATTERN WILL BE OUT OF THE SOUTHWEST...WITH THE MAIN UPPER TROUGH STILL OFF TO THE WEST OF THE REGION. CENTER OF THE UPPER RIDGE WILL BE OVER SOUTHERN FLORIDA. WITH GOOD SOUTH TO SOUTHWESTERLY LOW-LEVEL FLOW EXPECTED TO OCCUR THROUGH THE PERIOD...MOISTURE IS EXPECTED TO CONTINUE TO INCREASE EACH DAY ACROSS THE REGION. AFTERNOON TEMPERATURES WILL CONTINUE TO BE IN THE LOWER 90S FOR MOST AREAS...WITH OVERNIGHT LOWS FALLING INTO THE LOWER 70S. WITH THE MOISTURE INCREASE EXPECT TO SEE SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP EACH AFTERNOON DURING THE TIME OF MAXIMUM HEATING. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS WITH PREVIOUS DAYS FORECAST RUNS...THE GFS/ECMWF BEGIN TO DIVERGE WITH THEIR SOLUTIONS THROUGH THE LONGER TERM. BOTH MODELS DIVE AN UPPER TROUGH SOUTHEASTWARD OUT OF THE UPPER PLAINS STATES FRIDAY NIGHT INTO SATURDAY...THEN CREATE A CUTOFF LOW ACROSS THE EASTERN US. ITS THE DEVELOPMENT AND PLACEMENT OF THIS CUTOFF THAT THE MODELS DISAGREE WITH OVER THE WEEKEND. THE GFS IS FURTHER SOUTH AND WEAKER THAN THE ECMWF...WITH THE ECMWF LIFTING THE LOW QUICKER TOWARDS THE NORTHEAST SUNDAY INTO MONDAY. OBVIOUSLY THE PLACEMENT AND MOVEMENT OF THE UPPER LOW WILL EVENTUALLY HAVE AN AFFECT ON THE FINAL PLACEMENT AND MOVEMENT OF THE EXPECTED COLD FRONT THAT WILL MOVE THROUGH THE REGION THIS WEEKEND. BOTH MODELS HAVE A PREFRONTAL TROUGH ACROSS THE REGION THROUGH SATURDAY. WHATEVER THE FINAL TRACK IS FOR THE UPPER LOW...BOTH MODELS SHOW THE FRONT PUSHING TOWARDS THE COAST ON SUNDAY...WITH THE ECMWF BEING FASTER WITH THE TRACK. HAVE LEANED A LITTLE MORE TOWARDS A BLEND OF THE TWO MODELS FOR NOW. EXPECTING SHOWERS AND THUNDERSTORMS TO OCCUR EACH AFTERNOON THROUGH SUNDAY...WITH DRYING FINALLY BEGINNING TO PUSH IN SUNDAY NIGHT. THE REGION SHOULD BEGIN TO SEE SOME COOLER TEMPERATURES AND DRYING TO START OFF THE WORK WEEK BEHIND THE COLD FRONTAL PASSAGE. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... ISOLATED SHOWERS CONTINUE ACROSS THE FORECAST AREA THIS EVENING BUT CURRENT RADAR TRENDS SHOW NO THREAT AT THE TERMINALS. HIGH RESOLUTION MODELS ALL INDICATING IFR/MVFR CONDITIONS DEVELOPING LATE TONIGHT. THIS AGREES WITH PERSISTENCE...SO WILL INCLUDE MORNING STRATUS AND/OR FOG IN ALL TAF SITES ON WEDNESDAY. COULD SEE ISOLATED SHOWERS OVERNIGHT GIVEN WEAK ISENTROPIC LIFT. CONDITIONS EXPECTED TO IMPROVE TO VFR AROUND MIDDAY WEDNESDAY AS SOUTHWEST WINDS INCREASE TO AROUND 5 TO 10 KNOTS. SCATTERED CONVECTION WILL RECONVENE DURING THE AFTERNOON ONCE AGAIN. . EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 99
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
651 PM EDT MON SEP 7 2015 .SYNOPSIS... AN INLAND WEDGE OF HIGH PRESSURE AND A COASTAL TROUGH WILL DISSIPATE TUESDAY AND TUESDAY NIGHT. ATLANTIC HIGH PRESSURE WILL THEN BUILD OVER THE SOUTHEAST UNTIL A COLD FRONT APPROACHES THE REGION LATE THIS WEEK. THE COLD FRONT WILL STALL OVER OR CLOSE TO THE AREA NEXT WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... DIURNAL CONVECTION WILL DIMINISH THROUGH THE EVENING WITH THE LOSS OF HEATING. THROUGH THE OVERNIGHT...THE FORECAST AREA WILL REMAIN ON THE EASTERN PERIPHERY OF A UPPER LOW SITUATED ALONG THE GULF COAST. LATE IN THE NIGHT...DIFLUENCE WILL INCREASE AND THE MODELS SHOW A NOTABLE SHORTWAVE MOVING INTO THE AREA FROM THE SOUTH. AS THE FORCING ALOFT INCREASES...THE MODELS DEPICT A WARM FRONT LIKE FEATURE LIFTING NORTHWARD WITH INCREASING SHOWER AND THUNDERSTORM DEVELOPMENT ACCOMPANYING IT. THE MODEL PRECIPITATION RESPONSE IS PRETTY CONSISTENT AMONGST THE SUITE OF MODELS AND LENDS CONFIDENCE TO BRINGING IN INCREASING POPS FROM LATE EVENING ON...MAINLY AT THE COAST AND AREAS SOUTH OF I-16 WHERE SURFACE MOISTURE FLUX CONVERGENCE WILL BE THE MOST INTENSE. POPS WILL RANGE FROM 10-20 PERCENT ACROSS THE FAR NORTHWESTERN TIER TO 50-60 PERCENT ALONG PARTS OF THE GEORGIA COAST. A MENTION OF HEAVY RAIN HAS BEEN ADDED TO THE MOST OF THE GEORGIA COASTAL ZONES GIVEN THE EXPECTED EFFICIENT RAINFALL RATES WITHIN THE VERY TROPICAL LIKE ATMOSPHERE. LOWS WILL BE QUITE SIMILAR TO LAST NIGHT...MAINLY IN THE 70-73 DEGREE RANGE AWAY FROM THE BEACHES. ANOTHER ROUND OF STRATUS DEVELOPMENT IS EXPECTED TONIGHT AS WELL...AND THERE COULD BE SOME AREAS THAT SEE LIGHT FOG DEVELOPMENT. FOR THE EARLY EVENING UPDATE...MADE MINOR ADJUSTMENTS TO HOURLY POPS TO MATCH GOING KCLX RADAR TRENDS AND TO SPEED UP THE INTRODUCTION OF LIKELY POPS ACROSS THE FAR SOUTHERN COASTAL ZONES PER RAP/H3R MODEL OUTPUT. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... THE INLAND WEDGE/COASTAL TROUGH WILL GRADUALLY WEAKEN TUESDAY. BETWEEN AN UPPER LOW CENTERED WEST OF THE REGION AND AN UPPER RIDGE BUILDING FROM THE SOUTHEAST...STRENGTHENING/MOIST SOUTHERLY FLOW WILL CONVERGE/BE FORCED ALOFT BY SURFACE FEATURES OVER THE FORECAST AREA...AND A WEAK WARM FRONT WILL ADVANCE NORTH THROUGH THE FORECAST AREA. THIS SCENARIO SHOULD SUPPORT YET ANOTHER WET MORNING ALONG THE COAST...ESPECIALLY ACROSS CENTRAL/SOUTHERN COASTAL COUNTIES. LIKELY POPS ARE IN ORDER FOR THESE AREAS TUESDAY MORNING...TAPERED TO SLIGHT CHANCE/CHANCE FARTHER NORTH/WEST. ALSO...PWATS EXCEEDING 2 INCHES WILL SUPPORT A THREAT FOR LOCALLY HEAVY RAIN. TUESDAY AFTERNOON...PRECIPITATION COVERAGE BECOMES MORE UNCERTAIN AS THE INLAND WEDGE/COASTAL TROUGH BECOME ILL-DEFINED...AND THE FOCUS FOR CONVECTION SHIFTS TO THE SEA BREEZE/CONVECTIVE OUTFLOW BOUNDARIES. CAPPED MAXIMUM AFTERNOON POPS AT AROUND 50 PERCENT...ESPECIALLY ACROSS NORTHERN/INLAND COUNTIES...BUT LOCALLY GREATER AMOUNTS COULD EVENTUALLY BE REQUIRED AS SHORT/NEAR TERM CONVECTIVE TRENDS COME INTO FOCUS. CLOUDS/PRECIPITATION SHOULD LIMIT INSTABILITY...AND THE POTENTIAL FOR SEVERE WEATHER REMAINS VERY LOW TUESDAY. OTHERWISE...HIGH TEMPERATURES IN THE MID/UPPER 80S APPEAR REASONABLE...HIGHEST SOUTH WHERE PRECIPITATION COVERAGE COULD WANE DURING THE TIME OF MAX HEATING...ALTHOUGH TEMPERATURES COULD STRUGGLE TO EXCEED TO THE LOWER 80S IF/WHERE CLOUDS/SHOWERS PERSIST. TUESDAY NIGHT...POPS OVER LAND SHOULD DIMINISH..AND THE FOCUS FOR ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS SHOULD SHIFT TO COASTAL COUNTIES ADJACENT COASTAL WATERS WHERE LOW LEVEL MASS/MOISTURE CONVERGENCE IS EXPECTED TO DEVELOP. LOW WILL RANGE FROM THE LOWER/MID 70S INLAND TO THE MID/UPPER 70S AT THE COAST. WEDNESDAY...HIGH PRESSURE WILL BUILD INTO THE REGION AT THE SURFACE AND ALOFT. SOUTH/SOUTHWEST FLOW ALOFT BETWEEN THE TROUGH TO THE WEST AND HIGH PRESSURE CENTERED TO THE EAST/NORTHEAST WILL MAINTAIN A FLOW OF TROPICAL MOISTURE FEATURING PWATS AROUND 2 INCHES ACROSS THE REGION. THUS...AT LEAST CHANCE POPS FOR SCATTERED SHOWERS/ THUNDERSTORMS ARE IN ORDER ACROSS THE REGION...ESPECIALLY DURING THE AFTERNOON AS THE SEA BREEZE ADVANCES INLAND. WHILE ELEVATED PWATS WILL CONTINUE TO SUPPORT A LOCALIZED THREAT FOR HEAVY RAIN...STRONGER INSTABILITY AS COMPARED WITH THE PAST FEW DAYS AND 0- 6 KM BULK SHEAR INCREASING TO 15-25 KT SUGGESTS SOME POTENTIAL FOR MULTICELL CLUSTERS OF THUNDERSTORMS ACCOMPANIED BY A LOW CHANCE FOR PULSE SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS WEDNESDAY AFTERNOON. MEANWHILE...OUTSIDE ANY THUNDERSTORMS HIGH TEMPERATURES IN THE UPPER 80S/LOWER 90S SHOULD BECOME COMMON AWAY FROM THE COAST. WEDNESDAY NIGHT...THE FOCUS FOR ISOLATED/SCATTERED SHOWERS/ THUNDERSTORMS SHOULD ONCE AGAIN SHIFT FROM INLAND COUNTIES TO COASTAL COUNTIES/ADJACENT COASTAL WATERS. DUE TO UNCERTAINTY REGARDING THE COVERAGE/IMPACTS OF WEDNESDAY AFTERNOON THUNDERSTORMS FORECAST LOW TEMPERATURES AGAIN RANGE FROM THE LOWER/MID 70S INLAND TO THE MID/UPPER 70S AT THE COAST. HOWEVER...A TIGHTENING PRESSURE GRADIENT AND PERSISTENT WEST/SOUTHWEST WINDS AHEAD OF DEVELOPING PRE- FRONTAL TROUGH NORTH OF THE REGION COULD HOLD TEMPERATURES IN THE 75-80F RANGE AT LOCATIONS WHERE NO RAIN OCCURS. THURSDAY...07/12Z MODEL TRENDS SUGGESTS THAT THE REGION WILL REMAIN POSITIONED BETWEEN ATLANTIC HIGH PRESSURE AND A LEE SIDE TROUGH NORTH/WEST OF THE FORECAST AREA. THE RESULTING WEST/SOUTHWEST WINDS AND COMPRESSIONAL HEATING SHOULD SUPPORT ABOVE NORMAL HIGH TEMPERATURES AT LEAST IN THE LOWER/MID 90S...AND 90F TEMPS COULD EVEN BE PUSHED TO THE COAST BEFORE THE SEA BREEZE DEVELOPS. MAX HEAT INDEX VALUES IN THE UPPER 90S/LOWER 100S COULD BE REALIZED THURSDAY AFTERNOON. ALSO...ISOLATED/SCATTERED THUNDERSTORMS COULD DEVELOP NEAR THE SEA BREEZE WHICH WILL STRUGGLE TO PUSH INLAND...AND CLUSTERS OF CONVECTION UPSTREAM COULD PUSH INTO THE REGION ESPECIALLY INLAND COUNTIES ESPECIALLY LATE. HOWEVER...A SUBTLE DRYING TREND COULD TRANSLATE TO FEW/NO DIURNAL SHOWERS/ THUNDERSTORMS. MAINTAINED CHANCE POPS INLAND AND SLIGHT CHANCE POPS ELSEWHERE...ESPECIALLY THURSDAY AFTERNOON...BUT COVERAGE OF CONVECTION COULD REMAIN SPARSE THURSDAY PM. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A FAIRLY PROGRESSIVE UPPER PATTERN LATE WEEK THROUGH THE WEEKEND WILL PUSH A COLD FRONT INTO THE AREA LATE FRIDAY OR SATURDAY. THIS FRONT IS EXPECTED TO STALL ACROSS SOUTHERN AREAS THROUGH THE WEEKEND. THE PRIMARY IMPACT WILL BE A SLIGHT INCREASE IN SHOWER AND TSTM COVERAGE ESPECIALLY ACROSS THE COASTAL WATERS AND SOUTHEAST GA THOUGH ALL AREAS WILL SEE SOME CONVECTION. DECREASING THICKNESSES AND GREATER SKY COVER WILL MAINTAIN HIGH TEMPS IN THE UPPER 80S. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... KCHS...VFR FOR MUCH OF THE PERIOD. MODELS SUGGEST ANY LOW CLOUDS SHOULD REMAIN WEST OF THE TERMINAL AS THE LOW-LEVEL FLOW VEERS SOUTHEAST WITH TIME. THERE ARE SIGNALS THAT A BAND OF RAIN COULD APPROACH THE TERMINAL FROM THE SOUTH BY 14-16Z TUESDAY...BUT CONFIDENCE IN THIS SCENARIO PANNING OUT THIS FAR OUT IS TOO LOW TO JUSTIFY A MENTION ATTM. KSAV...VFR THIS EVENING WITH INCREASING PROBABILITIES FOR MVFR CIGS/VSBYS AFTER 06Z. MODELS ARE SIMILAR IN SHOWING A LARGE AREA OF RAIN DEVELOPING ALONG THE NORTHEAST FLORIDA AND FAR SOUTHERN GEORGIA COAST LATER THIS EVENING...THEN TREKKING NORTH AND POTENTIALLY IMPACTING THE TERMINAL ROUGHLY 08-11Z. GIVEN THE SIMILARITIES NOTED IN BOTH THE H3R AND RAP MODELS...WILL GO AHEAD AND INTRODUCE A TEMPO GROUP DURING THIS TIME FOR 4SM -RA. EXPECT PREVAILING MVFR CIGS TO DEVELOP BY 07Z AHEAD OF THE RAIN WHICH WILL LINGER INTO MID-MORNING TUESDAY BEFORE BREAKING OUT. THE LATEST DATA SUGGEST CIGS WILL REMAIN ABOVE IFR THRESHOLDS...BUT VSBYS COULD BRIEFLY DROP TO IFR THRESHOLDS IN POCKETS OF HEAVIER RAINFALL. WILL NO INCLUDE ANY IFR CONDITIONS ATTM. EXTENDED AVIATION OUTLOOK...OUTSIDE ANY SHOWERS/THUNDERSTORMS VFR WILL PREVAIL MUCH OF THE TIME. && .MARINE... TONIGHT...THE PERSISTENT COASTAL TROUGH IS EXPECTED TO BE ALIGNED RIGHT AT THE COAST THIS EVENING AND THEN GRADUALLY DISSIPATE OR SHIFT ONSHORE THROUGH THE NIGHT. THE PREVAILING FLOW WILL BE MORE EASTERLY AND EVENTUALLY SOUTHEASTERLY AS THE NIGHT PROGRESSES. THE PRESSURE GRADIENT WILL NOT BE AS TIGHT AND WIND SPEEDS ARE EXPECTED TO TOP OUT IN THE 10-15 KT RANGE...MAINLY FOR THE GEORGIA WATERS LATE TONIGHT. SEAS WILL BE 2-3 FT...HIGHEST BEYOND 20 NM. SHOWERS AND STORMS ARE EXPECTED TO INCREASE FROM THE SOUTH LATE TONIGHT AND COULD PRODUCE LOCALLY HEAVY RAINFALL...REDUCING VISIBILITIES AT TIMES OVER THE WATERS. THE INLAND WEDGE/COASTAL TROUGH REGIME WILL GRADUALLY YIELD TO ATLANTIC HIGH PRESSURE WHICH WILL EXPAND WEST TUESDAY AND WILL PREVAIL UNTIL LATE WEEK. AS A RESULT...EAST/NORTHWEST WINDS WILL GIVE WAY TO SOUTHEAST WINDS TUESDAY...THEN WINDS WILL VEER TOWARD THE SOUTH/SOUTHWEST TUESDAY NIGHT THROUGH FRIDAY. THROUGH MIDWEEK...WINDS MAINLY 10-15 KT AND SEAS 1-3 FT WILL PREVAIL. THEN...AHEAD OF AN APPROACHING COLD FRONT THE GRADIENT WILL TIGHTEN...AND WINDS WILL INCREASE TO 15-20 KT AND SEAS WILL BUILD TO 2-4 FT. WHILE THE PROBABILITY FOR SMALL CRAFT ADVISORY CONDITIONS WILL INCREASE THROUGH THE LATTER HALF OF THE WEEK...GUIDANCE MAINTAINS WINDS LESS THAN 25 KT AND SEAS BELOW 6 FT THROUGH THE PERIOD. THE COLD FRONT WILL ADVANCE IN THE WATERS AND WILL STALL NEXT WEEKEND...SO WINDS/SEAS REMAIN UNCERTAIN AND WILL DEPEND ON THE TIMING/POSITION OF THE FRONT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
115 PM EDT MON SEP 7 2015 .SYNOPSIS... BROAD UPPER LEVEL LOW OVER THE SOUTHEASTERN STATES WILL SHIFT SOUTHWESTWARD INTO THE GULF OF MEXICO THROUGH TUESDAY AS SURFACE HIGH PRESSURE BUILDS IN FROM THE NORTH. DEEP AND MOIST FLOW FROM THE ATLANTIC WILL CONTINUE ACROSS THE REGION. AN UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED WEATHER FOR THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC STATES WILL CONTINUE TO RIDGE INTO THE CAROLINAS AND GEORGIA THROUGH TONIGHT. BROAD UPPER LEVEL LOW CENTERED OVER AL/GA BORDER WILL SHIFT SOUTHWESTWARD INTO THE GULF OF MEXICO. DEEP AND MOIST FLOW FROM THE ATLANTIC COMBINED WITH WEAK INSTABILITY WILL HOLD THE CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA THOUGH THE EVENING. MOSTLY CLOUDY SKIES EXPECTED. SPC HRRR INDICATING SCATTERED CONVECTION PUSHING INTO THE AREA FROM THE COAST THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR THE AFTERNOON. PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0 INCHES SO LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN DURING THE EVENING HOURS WITH LOSS OF DAYTIME HEATING. HIGH TEMPERATURES EXPECTED TO REACH THE MID AND UPPER 80S WITH LOWS TONIGHT IN THE UPPER 60S TO LOWER 70S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... WEAK UPPER RIDGING WILL CONTINUE TO EXPAND WESTWARD OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. A SOUTHEASTERLY SURFACE FLOW WILL BE BRINGING MOISTURE INTO THE REGION OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH THROUGH THE PERIOD AS A DEEPER SOUTH TO SOUTHWESTERLY FLOW PATTERN DEVELOPS THROUGH THE MID AND UPPER LEVELS OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE UPPER MISSISSIPPI AND OHIO VALLEYS. SEE NO REASON TO CHANGE MUCH WITH THE CURRENT HIGH CHANCE POPS THAT ARE IN THE CURRENT FORECAST EACH AFTERNOON FOR TUESDAY AND WEDNESDAY. THERE MAY BE SOME BREAKS IN THE ACTION EACH NIGHT...BUT WILL CONTINUE WITH SLIGHT CHANCE POPS FOR THE OVERNIGHT HOURS. THE THREAT OF SEVERE WEATHER REMAIN LOW. BIGGEST ISSUE MAY BE DEALING WITH PERIODS OF HEAVY RAINFALL IN ANY SLOWER MOVING SHOWERS/STORMS THAT DEVELOP...ESPECIALLY WITH THE MOIST PROFILES AND WEAK SHEAR. TEMPERATURES BOTH TUESDAY AND WEDNESDAY WILL WARM UP INTO THE LOWER 90S FOR AFTERNOON HIGHS...AND THE LOWER 70S FOR MORNING LOWS. && .LONG TERM /THURSDAY THROUGH MONDAY/... BOTH THE GFS AND ECMWF ADVERTISE A WEAK TROUGH MOVING INTO AND THROUGH THE REGION ON THURSDAY...WITH THE GFS BEING SLIGHTLY FASTER BUT NOT BY MUCH. DO EXPECT SCATTERED CONVECTION TO DEVELOP ACROSS THE REGION IN RESPONSE TO THIS TROUGH PUSHING TOWARDS AND THROUGH THE AREA ON THURSDAY AFTERNOON/EVENING. THE MODELS THEN BEGIN TO DIVERGE FROM FRIDAY INTO NEXT WEEK. BOTH BRING A SECOND DEEPER UPPER TROUGH INTO THE EASTERN UNITED STATES...BUT THE ECMWF IS MORE AGGRESSIVE AND DEEPER WITH CUTTING THIS LOW OFF BY SATURDAY MORNING...WHILE THE GFS IS SLOWER IN ITS MOVEMENT AND TENDS TO KEEP IT AS AN OPEN WAVE SATURDAY. GFS DOES BEGIN TO CUT THE LOW OFF SATURDAY NIGHT INTO SUNDAY...BUT REMAINS WEAKER AND FURTHER SOUTH WITH ITS LOW. WITH BOTH SOLUTIONS THE UPPER FLOW REMAINS SOUTHWESTERLY THROUGH SUNDAY...THEN TURNS WESTERLY BY MONDAY AS THE UPPER SYSTEM PUSHES OFF THE EAST COAST. THE SURFACE FRONT ASSOCIATED WITH THE UPPER LOW MOVES CLOSER TO BUT JUST WEST OF THE REGION THROUGH SATURDAY...BEFORE PUSHING EAST OF THE AREA SATURDAY NIGHT INTO SUNDAY. WILL CONTINUE MENTION OF HIGH CHANCE POPS FRIDAY INTO SATURDAY. THEN BY SUNDAY POPS DIMINISH SOMEWHAT DOWN TO SLIGHT CHANCE/CHANCE CATEGORY...WITH THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE AREA. POPS MAY TREND LOWER NEAR THE END OF THE PERIOD IF DRIER AIR CAN PUSH FAR ENOUGH INTO THE CWA BY THE BEGINNING OF NEXT WEEK. TEMPERATURES DURING THIS PERIOD WILL GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER THE WEEKEND AND INTO NEXT WEEK. && .AVIATION /17Z MONDAY THROUGH FRIDAY/... CHANCE FOR SHOWERS WITH ISOLATED THUNDER IN DEEP AND MOIST EASTERLY FLOW GIVEN WEAK INSTABILITY. THE BEST CHANCE SOUTH AND EAST...FROM OGB TO AGS/DNL. WILL MENTION VCSH MAINLY FOR THE AFTERNOON AND EARLY EVENING HOURS. WINDS WILL BE OUT OF THE NORTHEAST TO EAST AT 10 KNOTS OR LESS. MODELS INDICATING MVFR/IFR CIGS RETURNING AFTER 08/06Z. EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
958 AM EDT MON SEP 7 2015 .SYNOPSIS... BROAD UPPER LEVEL LOW OVER THE SOUTHEASTERN STATES WILL SHIFT SOUTHWESTWARD INTO THE GULF OF MEXICO THROUGH TUESDAY AS SURFACE HIGH PRESSURE BUILDS IN FROM THE NORTH. DEEP AND MOIST FLOW FROM THE ATLANTIC WILL CONTINUE ACROSS THE REGION. AN UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED WEATHER FOR THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC STATES WILL CONTINUE TO RIDGE INTO THE CAROLINAS AND GEORGIA THROUGH TONIGHT. BROAD UPPER LEVEL LOW CENTERED OVER AL/GA BORDER WILL SHIFT SOUTHWESTWARD INTO THE GULF OF MEXICO. DEEP AND MOIST FLOW FROM THE ATLANTIC COMBINED WITH WEAK INSTABILITY WILL HOLD THE CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA THOUGH THE EVENING. MOSTLY CLOUDY SKIES EXPECTED. SPC HRRR INDICATING SCATTERED CONVECTION PUSHING INTO THE AREA FROM THE COAST THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR THE AFTERNOON. PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0 INCHES SO LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN DURING THE EVENING HOURS WITH LOSS OF DAYTIME HEATING. HIGH TEMPERATURES EXPECTED TO REACH THE MID AND UPPER 80S WITH LOWS TONIGHT IN THE UPPER 60S TO LOWER 70S. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST 20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE UPPER MISSISSIPPI AND OHIO VALLEYS. WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN THE LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF THE COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION FROM THE NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A SURFACE TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE TROUGH IS FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT PUSHES INTO THE AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY OVER THE REGION SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS SOUTHWESTERLY FLOW ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE TROUGH DIGGING ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET ANOTHER FRONT INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE RIDGE SETTLES ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES BY SUNDAY NIGHT. WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER THE WEEKEND. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... MVFR CIGS EXPECTED TO LIFT TO VFR AROUND MID-DAY WHICH ALIGNS WELL WITH THE PERSISTENCE FORECAST. CHANCE FOR SHOWERS WITH ISOLATED THUNDER IN DEEP AND MOIST EASTERLY FLOW GIVEN WEAK INSTABILITY. THE BEST CHANCE SOUTH AND EAST...FROM OGB TO AGS/DNL. WILL MENTION VCSH MAINLY FOR THE AFTERNOON AND EARLY EVENING HOURS. WINDS WILL BE OUT OF THE NORTHEAST TO EAST AT 10 KNOTS OR LESS. MODELS INDICATING MVFR/IFR CIGS RETURNING AFTER 08/06Z. EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
643 AM EDT MON SEP 7 2015 .SYNOPSIS... AN UPPER LOW OVER THE FORECAST AREA WILL SHIFT SOUTHWESTWARD THROUGH TODAY WITH A COOL AND MOIST FLOW OFF THE ATLANTIC. AN UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED WEATHER FOR THE END OF THE WEEK. && .NEAR TERM /TODAY AND TONIGHT/... SURFACE ANALYSIS SHOWS AN AREA OF HIGH PRESSURE CENTERED OVER NEW ENGLAND CONTINUING TO RIDGE DOWN THE EAST COAST INTO THE CAROLINAS. MEANWHILE AN UPPER AREA OF LOW PRESSURE IS MOVING WESTWARD THROUGH THE SOUTHEAST. LATEST RADAR LOOP SHOWING SCATTERED SHOWERS BEING CONFINED MAINLY TO THE IMMEDIATE COAST AND LOWCOUNTRY. GFS INDICATING WEAK COASTAL SURFACE TROUGH MOVING ONSHORE LATER TODAY. SPC HRRR INDICATING SCATTERED CONVECTION PUSHING INTO THE AREA FROM THE COAST LATER THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR THE AFTERNOON. PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0 INCHES SO LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN DURING THE EVENING HOURS WITH LOSS OF DAYTIME HEATING. AFTERNOON HIGHS MOSTLY IN THE MIDDLE 80S WITH OVERNIGHT LOWS EARLY TUESDAY MORNING AROUND 70. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST 20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE UPPER MISSISSIPPI AND OHIO VALLEYS. WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN THE LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF THE COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION FROM THE NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A SURFACE TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE TROUGH IS FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT PUSHES INTO THE AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY OVER THE REGION SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS SOUTHWESTERLY FLOW ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE TROUGH DIGGING ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET ANOTHER FRONT INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE RIDGE SETTLES ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES BY SUNDAY NIGHT. WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER THE WEEKEND. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... MVFR TO POSSIBLY IFR CIGS POSSIBLE UNTIL AROUND 14Z-15Z THIS MORNING. MODELS SHOW IMPROVEMENT AROUND MID- DAY TO EARLY AFTERNOON WHICH ALIGNS WELL WITH THE PERSISTENCE FORECAST. ANOTHER CHANCE FOR CONVECTION LATER THIS AFTERNOON WITH THE BEST CHANCE SOUTH AND EAST. WILL MENTION VCSH MAINLY FOR THE AFTERNOON AND EARLY EVENING HOURS. WINDS WILL GENERALLY BE OUT OF THE NORTHEAST THROUGH THE PERIOD AT 10 KNOTS OR LESS. EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 87
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
322 AM EDT MON SEP 7 2015 .SYNOPSIS... AN UPPER LOW OVER THE FORECAST AREA WILL SHIFT SOUTHWESTWARD THROUGH TODAY WITH A COOL AND MOIST FLOW OFF THE ATLANTIC. AN UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED WEATHER FOR THE END OF THE WEEK. && .NEAR TERM /TODAY AND TONIGHT/... SURFACE ANALYSIS SHOWS AN AREA OF HIGH PRESSURE CENTERED OVER NEW ENGLAND CONTINUING TO RIDGE DOWN THE EAST COAST INTO THE CAROLINAS. MEANWHILE AN UPPER AREA OF LOW PRESSURE IS MOVING WESTWARD THROUGH THE SOUTHEAST. LATEST RADAR LOOP SHOWING SCATTERED SHOWERS BEING CONFINED MAINLY TO THE IMMEDIATE COAST. GFS INDICATING WEAK COASTAL SURFACE TROUGH MOVING ONSHORE LATER TODAY. SPC HRRR INDICATING SCATTERED CONVECTION PUSHING INTO THE AREA FROM THE COAST LATER THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR THE AFTERNOON. PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0 INCHES SO LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN DURING THE EVENING HOURS WITH LOSS OF DAYTIME HEATING. AFTERNOON HIGHS MOSTLY IN THE MIDDLE 80S WITH OVERNIGHT LOWS EARLY TUESDAY MORNING AROUND 70. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST 20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE UPPER MISSISSIPPI AND OHIO VALLEYS. WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN THE LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF THE COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION FROM THE NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A SURFACE TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE TROUGH IS FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT PUSHES INTO THE AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY OVER THE REGION SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS SOUTHWESTERLY FLOW ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE TROUGH DIGGING ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET ANOTHER FRONT INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE RIDGE SETTLES ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES BY SUNDAY NIGHT. WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER THE WEEKEND. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... MVFR TO POSSIBLY IFR CIGS COULD REDEVELOP AS A STRATUS DECK DEVELOPS ACROSS THE REGION. A 20 TO 25 KNOT LOW LEVEL JET SHOULD RESULT IN MAINLY STRATUS OVER FOG. MODELS SHOW IMPROVEMENT AROUND MID-DAY TO EARLY AFTERNOON WHICH ALIGNS WELL WITH THE PERSISTENCE FORECAST. ANOTHER CHANCE FOR CONVECTION LATER THIS AFTERNOON WITH THE BEST CHANCE SOUTH AND EAST. WILL MENTION VCSH MAINLY FOR THE AFTERNOON AND EARLY EVENING HOURS. WINDS WILL GENERALLY BE OUT OF THE NORTHEAST THROUGH THE PERIOD AT 10 KNOTS OR LESS. EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1019 PM EDT TUE SEP 8 2015 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 241 PM EDT TUE SEP 8 2015 A COLD FRONT WILL BRING RAIN CHANCES TO THE AREA INTO THURSDAY...THEN ANOTHER FRONT AND AN UPPER LOW WILL BRING MORE CHANCES FOR RAIN FRIDAY AND SATURDAY. MUCH COOLER AIR WILL MOVE IN BEHIND THE FRONTS. HIGHS ONLY IN THE 60S ARE EXPECTED THIS WEEKEND. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 955 PM EDT TUE SEP 8 2015 RADAR MOSAIC SHOWS RAIN HAS COMPLETELY FALLEN APART AND COME TO AN END ACROSS CENTRAL INDIANA...BUT ECHOES IN SOUTHERN ILLINOIS CONTINUE TO MOVE TOWARD THE SOUTHWESTERN COUNTIES. EXPECT TO SEE MOSTLY DRY CONDITIONS ACROSS THE AREA THE NEXT FEW HOURS BEFORE COVERAGE STARTS TO INCREASE ACROSS THE SOUTHWESTERN COUNTIES AND SLOWLY SPREAD TO THE NORTHEAST FROM THERE. WITH LITTLE INSTABILITY HAVE DECREASED THUNDERSTORM WORDING TO SLIGHT CHANCE TO GO ALONG WITH THE CHANCES FOR RAIN THAT WILL INCREASE LATER DURING THE OVERNIGHT. TEMPERATURES IN THE NORTHWESTERN COUNTIES DROPPED A DECENT BIT BEHIND THE SHOWERS AND HAD TO ADJUST THE LOWS THERE DOWN A COUPLE DEGREES...BUT THINK BASED ON UPSTREAM TEMPERATURES AND CLOUD COVER THAT THEY WILL NOT DROP MUCH MORE AND MAY INSTEAD INCREASE A BIT OVERNIGHT WITH AN INCREASED PUSH OF WARM ADVECTION IN THE LOW LEVELS. && .SHORT TERM.../WEDNESDAY THROUGH FRIDAY/ ISSUED AT 241 PM EDT TUE SEP 8 2015 FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE ENOUGH THAT A BLEND WAS USED. WITH AN UPPER TROUGH DEEPENING A BIT...A COLD FRONT MOVING THROUGH...AND AN UPPER JET TO THE NORTHWEST...FEEL THAT MOST AREAS ARE LIKELY TO SEE AT LEAST SOME RAIN ON WEDNESDAY. WILL CONTINUE WITH LIKELY POPS ALL AREAS. WILL TIME THEM AS BEST CHANCES NORTHWEST DURING THE MORNING AND SOUTHEAST LATER IN THE AFTERNOON. WITH THE POSSIBILITY OF A SURFACE WAVE RIDING ALONG THE FRONT WEDNESDAY NIGHT...KEPT POPS GOING ACROSS MUCH OF THE AREA...WITH HIGHEST POPS SOUTHEAST CLOSEST TO THE FRONT. KEPT SOME SLIGHT CHANCE POPS ACROSS THE SOUTH ON THURSDAY MORNING UNTIL THE SYSTEM CLEARS THE AREA. DRY CONDITIONS WILL THEN PERSIST THROUGH THURSDAY NIGHT. A SECONDARY COLD FRONT WILL MOVE THROUGH ON FRIDAY WITH A REINFORCING SHOT OF COOLER AIR. THE FRONT WILL NOT HAVE A LOT MOISTURE TO WORK WITH...SO KEPT POPS LOW. FOR TEMPERATURES THROUGH THE SHORT TERM...GENERALLY STAYED CLOSER TO THE WARMER MAV AS THE COOLEST AIR WILL NOT ARRIVE UNTIL THE SECOND FRONT ON FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... ISSUED AT 215 PM EDT TUE SEP 8 2015 ECMWF AND THE GFS SUGGEST AN UPPER LOW DIGGING OUT OF THE GREAT LAKES ON FRIDAY AND INTO THE OHIO VALLEY BY SATURDAY. WITH THESE DYNAMICS ALOFT...BUT LITTLE IN THE WAY OF DEEP MOISTURE...CLOUDS...COOLER TEMPS AND LIGHT PRECIP LOOK REASONABLE. WILL CONTINUE TO INCLUDE LOW CHC POPS FOR SHOWS AT THIS TIME. THE GFS AND ECMWF DEPICT DIFFERENT SOLUTIONS TO THE EVOLUTION OF THE LOW...THE GFS SHOWS THE UPPER LOW SLOWLY MEANDERING EAST INTO APPALACHIA ON SUNDAY AND MONDAY...WHILE THE ECMWF INDICATES A QUICK DEPARTURE TO THE EAST ON SUNDAY. IN EITHER CASE...INDIANA LOOKS TO REMAIN ON THE DRY AND COOL WEST SIDE OF THE DEPARTING SYSTEM. THUS WILL BEGIN TRENDING TOWARD A DRY FORECAST ON SUNDAY THROUGH TUESDAY AS FLOW ALOFT BECOMES MORE NORTHWESTERLY EARLY NEXT WEEK...LITTLE SUPPORT IS SEEN IN THE WAY OF FORCING DYNAMICS. THUS HAVE TRENDED DRY DURING THAT TIME. && .AVIATION /DISCUSSION FOR 090300Z TAF UPDATE/... ISSUED AT 1019 PM EDT TUE SEP 8 2015 MADE MINOR ADJUSTMENTS TO THE FIRST FEW HOURS AT THE TERMINALS AS MOST OF THE PRECIP HAS DIMINISHED. SCATTERED CONVECTION PERSISTS OVER SOUTH CENTRAL ILLINOIS AS IT MOVES E/NE...BUT CLOUD TOPS ARE WARMING AND PRECIP COVERAGE HAS LESSENED AS EVENING HAS PROGRESSED. OTHER ADJUSTMENT WAS TO BRING IN MVFR CEILINGS A BIT FASTER AT BOTH KHUF AND KLAF BASED ON CURRENT OBS OVER ILLINOIS. RAP 925MB RH PROGS INDICATING DEEPER MOISTURE ADVECTING INTO THE REGION AFTER 06Z. COULD FLIRT WITH IFR CEILINGS AT KLAF LATE TONIGHT. 00Z DISCUSSION FOLLOWS. MVFR AND LOWER CONDITIONS POSSIBLE LATE TONIGHT AND WEDNESDAY MORNING WITHIN RAIN SHOWERS...OTHERWISE VFR CONDITIONS EXPECTED. AS EXPECTED...AREA OF RAIN SHOWERS GRADUALLY DIMINISHING IN COVERAGE AND INTENSITY AS IT PUSHES INTO A MORE STABLE AIRMASS OVER THE HOOSIER STATE. LITTLE IF ANY LIGHTNING NOW DETECTED ALONG THE LINE...AND EXPECT FURTHER WEAKENING OVER THE NEXT FEW HOURS. WILL CARRY VCSH AT ALL SITES FOR A FEW HOURS THROUGH THE EVENING. IN ADDITION...POTENTIAL BRIEF WIND GUST IMPACT AT KIND AS A WELL DEFINED OUTFLOW BOUNDARY HAS EXPANDED OUT AHEAD OF THE CONVECTION. LIKELY TO SEE A 10-15 MINUTE PERIOD WITH WINDS GUSTING TO NEAR 25KTS OUT OF THE NORTHWEST. WILL HIGHLIGHT THIS IN A TEMPO GROUP BETWEEN 00Z AND 01Z. SHOULD BE A LULL IN PRECIP COVERAGE OVERNIGHT BEFORE RETURNING PRIOR TO DAYBREAK WEDNESDAY AS A WAVE OF LOW PRESSURE TRACKS ALONG THE FRONT AND INTO THE REGION. NOT OVERLY IMPRESSED WITH AVAILABLE INSTABILITY AND OUTSIDE OF AN ISOLATED THUNDER THREAT...DO NO ANTICIPATE WIDESPREAD THUNDERSTORMS INTO THE DAY WEDNESDAY AT THIS POINT. MODEL SOUNDINGS INDICATE POTENTIAL FOR MVFR STRATUS TO IMPACT THE TERMINALS WEDNESDAY MORNING WITHIN RAIN SHOWERS...WITH CEILINGS LIFTING TO BETWEEN 4000-5000FT WEDNESDAY AFTERNOON. RAIN CHANCES SHOULD GRADUALLY END FROM NORTHWEST TO SOUTHEAST THROUGH THE AFTERNOON AS THE COLD FRONT SHIFTS SOUTH OF THE OHIO RIVER. WIND DIRECTION WILL BE CHAOTIC BUT SPEEDS GENERALLY LESS THAN 5-7KTS EXPECTED ON WEDNESDAY. WINDS WILL GRADUALLY BECOME NORTHERLY WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS IN. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...50 NEAR TERM...CP SHORT TERM...50 LONG TERM....PUMA AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1222 AM CDT MON SEP 7 2015 .SHORT TERM /TONIGHT/... ISSUED AT 305 PM CDT SUN SEP 6 2015 STILL SOME UNCERTAINTY ABOUT EVOLUTION OF SYSTEM TONIGHT. VARIOUS MODEL SOLUTIONS BEGINNING TO EITHER POINT TOWARD SLIGHTLY MORE PROGRESSIVE EVOLUTION OF CONVECTION OVERNIGHT...OR SLIGHTLY MORE NORTH PLACEMENT OF MAX. SO FAR CONVECTIVE TRENDS HAVE BEEN RAMPING UP SLOWLY DUE TO H700 TEMPS SITTING ABOVE 11-12C THIS AFTERNOON. BUT AS FRONT ENTERS NW/W IA EARLY THIS EVENING AND AREA BECOMES UNCAPPED AND H700 TEMPS COOL A COUPLE OF DEGREES...A RAPID INCREASE IN STORMS SHOULD OCCUR BETWEEN 4 PM AND 7 PM. DESPITE THE EXPECTED MODEL UNCERTAINTY...WE ARE IN NEAR RECORD TERRITORY FOR AVAILABLE ATMOSPHERIC MOISTURE FOR EARLY SEPTEMBER. THIS IS DUE IN PART TO A PROLONGED FETCH OF GULF MOISTURE WHICH IS FEEDING NORTHEAST INTO THE CENTRAL PLAINS AND GREAT LAKES. SECONDLY...A TROPICAL CONNECTION FROM THE SOUTHWEST US THAT RESULTED IN AN OLD TROPICAL SYSTEM EARLIER IN THE WEEK OFF THE COAST OF BAJA MEXICO BEING INGESTED IN THE MID TO UPPER LEVEL FLOW. PWAT VALUES WILL BE APPROACHING 2 TO 2.25 INCHES BETWEEN 00-06Z TONIGHT PLACING OUR VALUES IN THE 99TH/100TH PERCENTILE AND OVER 3 SDEV ABOVE NORMAL FOR THIS TIME OF YEAR. WARM CLOUD DEPTHS ARE NEAR 14.5KFT WHICH IS EXTREMELY DEEP. THERE REMAIN NUMEROUS FACTORS SUPPORTING EFFICIENT/HIGH RAINFALL RATES THIS EVENING...AND LOOKING AHEAD...AGAIN MONDAY NIGHT. BACK TO THE MODELS...CONSECUTIVE RUNS OF THE HRRR ARE SHOWING A MORE PROGRESSIVE EVOLUTION TO TONIGHTS CONVECTION WITH FORWARD PROPAGATING CORFIDI VECTORS ABOUT 20 KTS. BUT EVEN THIS IS DECEIVING IF RAINFALL RATES ARE 2-3 INCHES PER HOUR AT TIMES...AND STILL SUGGESTS A QUICK COUPLE OF INCHES OF RAIN IN THE MORE VIGOROUS CELLS. WITH ANY LOCALIZED TRAINING...STILL A POTENTIAL FOR ISOLATED 3 TO 4 INCHES AMOUNTS OVERNIGHT. THE NAM IS LEANING TOWARD THE MORE PROGRESSIVE HRRR OVERNIGHT WITH THE GFS RAMPING UP CONVECTION BETWEEN 00-06Z ON THE NOSE OF THE INCREASING LOW LEVEL JET ALONG THE INVERTED TROUGH WITHIN THE ZONE OF MAXIMUM SFC CONVERGENCE. THE QPF MAX IS CENTERED OVER HIGHWAY 30...ROUGHLY BETWEEN US 20/I80 FROM GREENE TO MARSHALL COUNTIES. WITH THAT ADDED UNCERTAINTY TONIGHT AND THE POSSIBLE NORTHERLY SHIFT BY 20 MILES OF THE QPF MAX...WILL BE ADDING ONE ROW OF COUNTIES TO TONIGHTS FFA ALONG US 20. REALIGNING THE WATCH NOW IS RISKY...DUE TO THE POSSIBILITY OF THE MODELS ARE NOT PROPERLY ACCOUNTING FOR A STRONGER OUTFLOW BOUNDARY LATER IN THE EVENING...WHICH WOULD THEN BE FEEDING OFF AN INCREASING LOW LEVEL JET OVERNIGHT. THERE MAY ACTUALLY BE TWO FAVORED AREAS OF HEAVY RAINFALL...EARLIER BETWEEN US20/30 AND LATER ALONG AND SOUTH OF I80. NONE THE LESS...THE RISK FOR FLASH FLOODING AND SUBSEQUENT ISSUES REMAINS. TIMING OF THE EVENT SUGGESTS THAT STORMS SHOULD BE IN FULL SWING BETWEEN 02-09Z WITH ACTIVITY REMAINING STRONG BUT SLOWLY DIMINISHING BETWEEN 09-13Z MONDAY OVER THE SOUTH/SOUTHEAST. LOWS TONIGHT WILL FALL TO THE LOWER 70S SOUTH TO NEAR 60 OVER THE FAR NORTHWEST AS THE COOLER AIR BEGINS TO FILTER INTO THE REGION TONIGHT. TONIGHTS RAINFALL WILL PRIME THE REGION FOR A MORE SIGNIFICANT RISK OF FLOODING MONDAY NIGHT AND THIS IS COVERED IN THE EXTENDED DISCUSSION. .LONG TERM /MONDAY THROUGH SUNDAY/... ISSUED AT 305 PM CDT SUN SEP 6 2015 A POTENTIALLY SIGNIFICANT HEAVY RAIN AND FLOODING EVENT MAY BE SHAPING UP EARLY THIS WEEK. THE COLD FRONT SAGGING DOWN INTO IOWA TONIGHT...AS DISCUSSED IN THE SHORT TERM SECTION ABOVE...WILL LIKELY STALL ACROSS SOUTHERN IOWA BY MONDAY MORNING THEN RETREAT BACK NORTHWARD A BIT TOWARD CENTRAL IOWA DURING THE DAY. DESTABILIZATION WILL BE LIMITED BY DEBRIS CLOUDS AND A LACK OF LOW LEVEL WARM AIR ADVECTION OVER MOST OF THE FORECAST AREA...PLUS THERE WILL BE NO LARGE SCALE FORCING MECHANISM FOR CONVECTION FOR MOST OF THE DAY. NEVERTHELESS THE AIRMASS WILL BE JUICED ENOUGH WITH THE BOUNDARY WOBBLING AROUND THAT LOW POPS ARE MAINTAINED ON MONDAY. BEGINNING LATE MONDAY AFTERNOON AND ESPECIALLY ON MONDAY NIGHT THE ATMOSPHERE APPEARS TO BE SETTING UP FOR A SIGNIFICANT...POSSIBLY EXTREME HEAVY RAINFALL EVENT. ALONG AND SOUTH OF THE NEARLY STATIONARY FRONTAL ZONE PWAT VALUES WILL BE NEAR RECORDS WITH SUBSTANTIAL MOISTURE TRANSPORT CONTINUING FROM THE GULF ESPECIALLY AS THE NOCTURNAL LOW LEVEL JET KICKS IN AFTER DARK. CONCURRENTLY...A SECOND FAIRLY ROBUST MID LEVEL SHORTWAVE WILL ROUND THE BASE OF BROAD CYCLONIC FLOW ALOFT AND PROVIDE A TRIGGER FOR WIDESPREAD THUNDERSTORM DEVELOPMENT. WITH WARM CLOUD DEPTHS IN EXCESS OF 15 KFT IN FORECAST SOUNDINGS AND THE COMBINATION OF OTHER FACTORS...WE WILL BE PRIMED FOR VERY EFFICIENT RAINFALL RATES AND POTENTIALLY TRAINING OR SLOW MOVING STORMS NEAR THE FRONTAL ZONE. THIS COULD LEAD TO WIDESPREAD RAINFALL AMOUNTS IN THE 2 TO 3 INCH RANGE WITHIN A BROAD SWATH ACROSS THE AREA...AND LOCALIZED AMOUNTS OF 6 INCHES OR MORE ARE DEFINITELY CONCEIVABLE. IN TERMS OF THE FLOODING EFFECTS OF SUCH RAINFALL...MUCH WILL DEPEND ON WHERE IT FALLS AND WHETHER IT OCCURS IN THE SAME AREA AS THE HEAVIEST RAINFALL TONIGHT...WHICH IS IN TURN DEPENDENT ON THE DIFFICULT TO PREDICT MOTIONS AND LOCATION OF THE FRONTAL BOUNDARY BY MONDAY EVENING. IT IS LIKELY...IN ANY EVENT...THAT A SECOND FLASH FLOOD WATCH WILL BE NEEDED AFTER TONIGHTS RAINFALL PANS OUT...AND THAT IT MAY NEED TO HAVE EVEN STRONGER WORDING FOR THE POTENTIAL EFFECTS MONDAY NIGHT INTO TUESDAY MORNING. SCATTERED THUNDERSTORMS MAY CONTINUE TO FESTER ACROSS OUR SOUTHERN COUNTIES ON TUESDAY AS THE FRONTAL ZONE LINGERS NEAR THE IOWA/MISSOURI BORDER...BUT THEN ANOTHER SHORTWAVE TROUGH WILL MOVE OVERHEAD AROUND TUESDAY EVENING AND FINALLY CLEAR OUT THE WET AIRMASS TO OUR SOUTH. THIS WILL BRING AN END OF ANY HEAVY RAIN THREAT FOR THE REMAINDER OF THE SEVEN DAY FORECAST...ALONG WITH NOTABLY COOLER AND DRIER WEATHER ACROSS IOWA. THERE WILL BE A CHANCE FOR SCATTERED SHOWERS AND STORMS AROUND THURSDAY AS A REINFORCING COLD FRONT SURGES ACROSS THE STATE...USHERING IN THE FIRST TRULY AUTUMNAL WEATHER OF THE SEASON AT THE END OF THIS WEEK WITH FRIDAY HIGHS IN THE 60S AND FRIDAY NIGHT LOWS IN THE 40S STATEWIDE. && .AVIATION...07/06Z ISSUED AT 1222 AM CDT MON SEP 7 2015 SOME STORMS TO STILL IMPACT KOTM KDSM AND KALO THROUGH THE OVERNIGHT HOURS...WITH FOG CHANCES AT THE NORTHERN SITES LOOKING SOMEWHAT UNCERTAIN. WINDS TO SHIFT AROUND TO THE SOUTHEAST TO SOUTH AGAIN LATE IN THE FORECAST PERIOD...WITH ANOTHER ROUND OF STORMS POSSIBLE BEGINNING LATE MONDAY AFTERNOON INTO MONDAY NIGHT. CIGS TO BE IN THE MVFR TO LOW VFR RANGE...BUT MAY DIP INTO IFR IF FOG DEVELOPS. && .HYDROLOGY... ISSUED AT 305 PM CDT SUN SEP 6 2015 AS REFERENCED IN THE PREVIOUS DISCUSSIONS...TWO HEAVY RAINFALL EVENTS ARE POSSIBLE TONIGHT THROUGH TUESDAY MORNING WITH THE FOCUS FROM NORTH CENTRAL TO SOUTHERN IOWA. WIDESPREAD RAINFALL AMOUNTS OF 2 TO 3 INCHES ARE EXPECTED WITH AMOUNTS EXCEEDING 5 INCHES POSSIBLE DURING THIS PERIOD. MONDAY NIGHTS EVENT IS STILL EXPECTED TO BE OF GREATER MAGNITUDE...SO SOME REEVALUATION OF THE WATCH OUTLINE WILL OCCUR BETWEEN THIS EVENING AND TOMORROW MORNING AFTER TONIGHTS RAINFALL REPORTS ARE GATHERED. IN BOTH EVENTS...EFFICIENT RAIN PRODUCING STORMS WILL PRODUCE HEAVY RAINFALL OVER A SHORT PERIOD OF TIME. SIGNIFICANT RUNOFF AND/OR PONDING OF WATER IS LIKELY IN SOME AREAS LEADING TO A FLASH FLOOD THREAT. THE EVENT MAY EVOLVE INTO A RIVER FLOODING THREAT THROUGH MID TO LATE WEEK AS THE RUNOFF REACHES THE LARGER STREAMS. THE MAGNITUDE OF RIVER FLOODING ON ANY GIVEN MAINSTEM RIVER WILL DEPEND ON BOTH RAINFALL AMOUNTS AND BASIN COVERAGE IN THE NEXT 48 TO 60 HOURS. && .DMX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR ADAIR-ADAMS- APPANOOSE-AUDUBON-BOONE-CASS-CLARKE-DALLAS-DAVIS-DECATUR-GREENE- GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-POLK- POWESHIEK-RINGGOLD-STORY-TAMA-TAYLOR-UNION-WAPELLO-WARREN-WAYNE. && $$ SHORT TERM...REV LONG TERM...LEE AVIATION...BEERENDS HYDROLOGY...REV
AREA FORECAST DISCUSSION
NWS GOODLAND KS
557 PM MDT TUE SEP 8 2015 .UPDATE... ISSUED AT 539 PM MDT TUE SEP 8 2015 A FEW THUNDERSTORMS HAVE POPPED UP IN N-S ORIENTED INSTABILITY AXIS ACROSS EASTERN HALF OF CWA. EXPECT CINH TO STEADILY INCREASE OVER THE NEXT 2 HOURS WHICH WILL ULTIMATELY LIMIT THE COVERAGE AND DURATION THROUGH THE EARLY EVENING. SEEMS TO BE A PRETTY SHARP MOISTURE GRADIENT ACROSS THE AREA ATTM WITH DEWPOINTS AROUND 20 DEGREES COOLER IN THE WEST. WITH LIGHT WINDS AND CLEAR SKIES MAY HAVE TO RETHINK LOW TEMPS...AND HAVE ALSO MODIFIED FOG FORECAST A BIT TO REFLECT THIS ORIENTATION. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 222 PM MDT TUE SEP 8 2015 WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW ACROSS CENTRAL ROCKIES AND OVER OUR CWA ON WESTERN EXTENT OF LARGE SCALE TROUGH. AXIS OF SUBSIDENCE IS CURRENTLY IN PLACE AS A SHORTWAVE TROUGH IS MOVING ACROSS CENTRAL KANSAS. AT THE SURFACE HIGH PRESSURE IS BUILDING INTO OUR CWA FROM THE NORTHERN PLAINS WITH A COLD FRONT THAT MOVED THROUGH OUR CWA EARLY THIS MORNING EXTENDING FROM NORTHEAST KANSAS THROUGH SOUTH CENTRAL KANSAS. TONIGHT...DRY CONDITIONS SHOULD PERSIST THROUGH THE OVERNIGHT PERIOD WITH SUBSIDENCE PERSISTING THROUGH MOST OF THE NIGHT...AND DEEP DRY AIR MASS IN PLACE. EARLY IN THE EVENING STEEP LAPSE RATES LEE TROUGH REBUILDS ALONG KS/CO BORDER OVERNIGHT WITH SOUTHERLY FLOW BRINING HIGH BL MOISTURE IN PLACE. TREND IN GUIDANCE HAS BEEN TO TO SHOW BETTER MIXING AND BL RH STAYING UP LIMITING FOG POTENTIAL. NAM AND RAP DO STILL SHOW SOME REDUCED VISIBILITIES AND I FELT COMFORTABLE KEEPING MENTION IN FORECAST FOR NOW. WEDNESDAY...A QUICK MOVING/WEAK SHORTWAVE TROUGH WILL ROTATE THROUGH NW FLOW JUST NORTH OF OUR CWA. DRY LAYER IN PLACE LOWERS OVERALL CONFIDENCE IN COVERAGE...HOWEVER GUIDANCE IS SHOWING INITIATION EITHER UPSTREAM OR ALONG SURFACE TROUGH AND TRACKING EAST ACROSS THE NORTHERN HALF OF OUR CWA. IF A CELL WERE TO DEVELOP ML CAPE VALUES AROUND 2000 J/KG AND EFFECTIVE SHEAR VALUES AROUND 35KT COULD SUPPORT A LIMITED SEVERE THREAT. IM JUST NOT SURE IF ANYTHING WILL EVEN DEVELOP CONSIDERING THE DRY AIR MASS IN PLACE. I KEPT SLIGHT CHANCE POPS IN THE AFTERNOON...COVERING POTENTIAL. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 255 PM MDT TUE SEP 8 2015 SEVERAL SHORT WAVE TROUGHS MOVE ACROSS THE CENTRAL HIGH PLAINS REGION WEDNESDAY NIGHT...THURSDAY NIGHT...AND FRIDAY EVENING. THE UPPER PATTERN BECOMES MORE AMPLIFIED AS THE SHORT WAVE TROUGHS DIVE INTO THE BASE OF THE MAIN UPPER TROUGH POSITIONED OVER THE MISSISSIPPI VALLEY REGION AS THE UPPER RIDGE AMPLIFIES OVER THE WESTERN UNITED STATES THURSDAY THROUGH FRIDAY NIGHT AND TRANSITIONS EASTWARD OVER THE ROCKIES AND HIGH PLAINS SATURDAY NIGHT. WITH A SURFACE TROUGH/FRONTAL BOUNDARY REMAINING IN THE VICINITY OF THE FORECAST AREA THESE SHORT WAVE TROUGHS TRANSITIONING THE REGION WILL HELP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP EACH DAY FROM LATE WEDNESDAY THROUGH EARLY FRIDAY. BY LATE FRIDAY THE FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE REGION AND SURFACE HIGH PRESSURE MOVES INTO THE AREA. TEMPERATURES WILL WARM THROUGH THURSDAY AHEAD OF THE FRONT WITH HIGH TEMPERATURES ONLY EXPECTED TO REACH IN TO THE 70S ON FRIDAY. TEMPERATURES WILL REBOUND QUICKLY THROUGH THE WEEKEND AND INTO NEXT WEEK AS SOUTHERLY NEAR SURFACE FLOW RETURNS AND THE REGION REMAINS UNDER WEAK RIDGING THROUGH THE WEEKEND AS THE UPPER PATTERN UNDERGOES A TRANSITION TO A RIDGE OVER THE EASTERN HALF OF THE UNITED STATES WHILE THE NEXT SIGNIFICANT LONG WAVE TROUGH DEEPENS OVER THE WESTERN UNITES STATES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 539 PM MDT TUE SEP 8 2015 VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH A SMALL WINDOW BTWN 10Z AND 15Z WHERE FOG MAY DEVELOP. CHANCES ARE BEST AT MCK BUT IT WILL NOT BE OUT OF THE QUESTION THAT GLD SEES AN HOUR OR TWO OF IFR CONDITIONS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...DR LONG TERM...LOCKHART AVIATION...JRM
AREA FORECAST DISCUSSION
NWS TOPEKA KS
428 PM CDT MON SEP 7 2015 .SHORT TERM...(THIS EVENING THROUGH Tuesday) ISSUED AT 402 PM CDT MON SEP 7 2015 Showers and isolated storms continued off and on through the afternoon hours in a zone of 1000-900mb convergence, weak isentropic lift and the presence of a weak wave. Although the bulk of the precipitation has moved east into missouri expect isolated to scattered showers to continue across east central Kansas into the early evening hours. Further north near the Nebraska border where few clouds have allowed temperatures to warm into the lower to mid 90s. Latest measoanalysis shows about 40 to 50kts of effective shear, 1500-3000 J/kg of CAPE and no cap in place. Isolated thunderstorms have developed just to the northwest of the forecast area and were moving northeast across southern Nebraska at 1930Z. Latest runs of the HRRR and the RAP suggest further development across north central Kansas into the evening hours, with additional development from central Kansas across northeast Kansas through the evening hours. Storms that can develop across the northern counties may be severe with hail, strong winds and an isolated tornado possible. Another round of storms is expected overnight into Tuesday morning as the upper level trough progresses eastward across the Northern and Central Plains. Good moisture transport is expected into northeast Kansas overnight with precipitable water around 2 inches which will increase the potential for locally heavy rainfall. The front is expected to move slowly southeast across the forecast area on Tuesday then moving out of east central Kansas Tuesday evening. Showers and thunderstorms will likely be ongoing in the morning hours and then continue along the boundary in the afternoon. Clouds south of I-70 have kept temperatures in check in the upper 70s to upper 80s. Will likely still see some fluctuations in temperatures through the late afternoon where the sun can come out. Tonight, lows should cool into the low to mid 70s with highs on Tuesday only in the low to mid 80s. .LONG TERM...(Tuesday NIGHT THROUGH Monday) ISSUED AT 402 PM CDT MON SEP 7 2015 Cold front and associated showers and thunderstorms should be moving to the southeast out of east central KS Tuesday evening. Then surface high pressure builds in with pleasant temperatures and lower humidities for Wednesday and Wednesday night. Northwest flow aloft then sets up through the end of the week with the first in a series of disturbances possibly affecting north central KS by late Thursday afternoon. That system moves through Thursday night through Friday with a good chance of thunderstorms during this time. Subsidence behind the trough and associated surface high pressure builds in for Saturday, and an upper ridge builds eastward for Sunday and Monday, keeping the weekend into Monday dry. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Tuesday AFTERNOON) ISSUED AT 1236 PM CDT MON SEP 7 2015 Currently a weak shortwave is still making its way over northeast KS. A few showers remain to the South of the terminals, but trends continue in weakening and decreasing coverage. Improvements in CIGS at KTOP should continue over the next couple hours. The balance of the afternoon and early evening look VFR at this point. Confidence into the evening decreases with storm chances once again in the overall picture. However, coverage and exact timing are not certain. Have included VCTS in the overnight period again as the Low Level Jet will still be influencing the terminals and low- level boundary will still be a factor in the overall forecast likely through the entire period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...GDP AVIATION...Drake
AREA FORECAST DISCUSSION
NWS GOODLAND KS
306 PM MDT MON SEP 7 2015 .SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY) ISSUED AT 143 PM MDT MON SEP 7 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS. THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE. I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH MODEL CONSENSUS. REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500 J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE SOUTHEAST THIS EVENING. RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO MONITOR NEED FOR NEW DENSE FOG ADVISORY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 230 PM MDT MON SEP 7 2015 THE WESTERLY FLOW ALOFT ACROSS THE CENTRAL HIGH PLAINS TURNS NORTHWESTERLY BY THURSDAY AND MORE NORTHERLY BY FRIDAY AND SATURDAY AS THE HIGH PRESSURE AREA ALOFT OVER NORTHERN MEXICO RETROGRADES AND MERGES WITH THE HIGH IN THE EASTERN PACIFIC TO FORM A RIDGE OVER THE WESTERN UNITED STATES WHILE SHORT WAVES EMBEDDED IN THE UPPER FLOW MOVE THROUGH THE CENTRAL HIGH PLAINS AND INTO THE BASE OF THE TROUGH DEEPENING IN THE MISSISSIPPI VALLEY REGION. EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT AS A RESULT OF THESE DISTURBANCES MOVING ACROSS THE REGION WITH THE SURFACE FRONTAL BOUNDARY REMAINING STALLED IN THE VICINITY OF THE FORECAST AREA THROUGH THE END OF THE WEEK. EXPECT DAYTIME HIGHS MAINLY IN THE 80S WITH LOWS MAINLY IN THE 50S THROUGH THIS PERIOD. SOMEWHAT COOLER TEMPERATURES ARE EXPECTED ON FRIDAY AND SATURDAY WITH DRY CONDITIONS SATURDAY AND SUNDAY IN THE WAKE OF THE STRONGER SHORT WAVE TROUGH ALOFT AND THE HIGH PRESSURE AREA TO FOLLOW A COLD FRONT ACROSS THE REGION. SURFACE HIGH PRESSURE MOVES OUT OF THE FORECAST ARE ON SUNDAY WITH THE LEE TROUGH DEVELOPING AND TEMPERATURES WARMING AGAIN WITH SOUTHWEST SURFACE FLOW AND THE WEAKENING RIDGE ALOFT OVER SOUTHWEST U.S. EXTENDING INTO THE CENTRAL HIGH PLAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1145 AM MDT MON SEP 7 2015 LOW STRATUS/CIGS SHOULD INCREASE TO VFR BY THE MIDDLE OF THE AFTERNOON AT BOTH KGLD AND KMCK. VIS SATELLITE ALREADY SHOWING BACK EDGE OF STRATUS JUST SW OF KGLD AND THIS SHOULD CONTINUE TO THE NORTHEAST AS INDICATED BY SHORT RANGE GUIDANCE LOW LEVEL MOISTURE FIELDS. SHOWERS/THUNDERSTORMS ARE STILL POSSIBLE ACROSS THE AREA THIS AFTERNOON/EVENING WITH FRONT LINGERING JUST SOUTH OF KGLD AND ADDITIONAL UPPER LEVEL DISTURBANCES EXPECTED TO MOVE THROUGH REGION. HIGH RES GUIDANCE SHOWING A LULL IN ACTIVITY THIS AFTERNOON WITH ACTIVITY INCREASING IN COVERAGE THIS EVENING. AT THIS POINT CONFIDENCE WAS TOO LOW TO INCLUDE MENTION OF THUNDER IN TAFS BUT I DID KEEP VCSH IN PLACE. GUIDANCE SHOWING LOW STRATUS/FOG REDEVELOPING WITH LIGHT EAST/NORTHEAST FLOW OVER CENTRAL NEBRASKA AND ADVECTING TO THE SOUTHWEST OVER KMCK THEN KGLD...LINGERING THROUGH MID MORNING. THERE MAY BE A PERIOD OF LIFR VIS/CIG...HOWEVER CONFIDENCE IN PREVAILING CONDITIONS IS LEANING TOWARDS IFR VIS (1-2SM)BASED ON MODEL CONSENSUS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...LOCKHART AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
144 PM MDT MON SEP 7 2015 .SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY) ISSUED AT 143 PM MDT MON SEP 7 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS. THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE. I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH MODEL CONSENSUS. REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500 J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE SOUTHEAST THIS EVENING. RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO MONITOR NEED FOR NEW DENSE FOG ADVISORY. .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 240 AM MDT MON SEP 7 2015 FOR THE MAJORITY OF THE LONG TERM...THURSDAY 12Z THROUGH SATURDAY 12Z...THE UPPER LEVEL FLOW IS FAIRLY SIMILAR IN THE GFS AND EUROPEAN. THERE IS A TROUGH STRETCHING OVER THE GREAT LAKES REGION AND DOWN INTO THE SOUTHEASTERN STATES...WITH HIGH PRESSURE SITTING OVER THE WESTERN AND SOUTHWESTERN STATES. AFTER 12Z ON SATURDAY THE MODELS START TO DIFFER ON HOW THEY HANDLE THE TROUGH IN THE EASTERN HALF OF THE US. THE GFS STARTS TO PUSH THE TROUGH OUT WHEREAS THE EUROPEAN HAS THAT TROUGH BECOMING MUCH STRONGER...WITH A CLOSED LOW AND KEEPS THE TROUGH OVER THE EASTERN REGION. THIS IS SOMETHING TO KEEP AN EYE ON AS WE GET CLOSER TO THIS COMING WEEKEND. AS FAR AS PRECIPITATION CHANCES...THURSDAY HAS SOME SLIGHT CHANCES FOR STORMS OVER THE SOUTHERN AND EASTERN PORTIONS OF THE CWA IN THE AFTERNOON INTO THE EVENING. GREATER PRECIP CHANCES WILL OCCUR IN THE EVENING HOURS. SURFACE CAPES ARE SHOWING TO REACH UP TO 2000 J/KG...THE EUROPEAN HAS THE HIGHER CAPE VALUES BUT THE GFS STILL SHOWS SOME FAIRLY SIGNIFICANT VALUES. BULK SHEAR IS NOT IMPRESSIVE. FRIDAY HAS THE GREATEST POTENTIAL FOR PRECIPITATION DURING THE PERIOD. THERE ARE SOME SLIGHT CHANCE POPS FRIDAY AFTERNOON BUT STORM CHANCES INCREASE FRIDAY EVENING INTO THE OVERNIGHT HOURS. THIS IS DUE TO A 700MB SHORTWAVE MOVING THROUGH THE CWA IN THE GFS AT 18Z FRIDAY INTO 06Z SATURDAY...IN ADDITION TO SURFACE CAPE VALUES AROUND 1900 J/KG AND BULK SHEAR REACHING UP TO 50 KTS. THESE STORMS WILL MOVE OUT FAIRLY QUICK. THE EUROPEAN DOES NOT SHOW THIS SAME PATTERN...THIS IS LIKELY DUE TO IT STRENGTHENING THE TROUGH IN THE EASTERN US. THIS IS DEFINITELY SOMETHING TO KEEP AN EYE ON. AS OF RIGHT NOW...SLIGHT CHANCE AND CHANCE POPS ARE BEING FORECASTED. SATURDAY AND SUNDAY WILL DRY OUT. THE GFS HAS THE HIGH PRESSURE STILL DOMINATING IN THE WESTERN STATES AND ZONAL UPPER LEVEL FLOW STARTING TO FORM OVER THE NORTHWEST. THE EUROPEAN UPPER LEVEL FLOW IS DIFFERENT BUT STILL SHOWS DRY CONDITIONS. HIGH TEMPERATURES WILL BE IN THE LOW TO MID 80S EACH DAY. A POSSIBLE SLIGHT TEMPERATURE DECREASE FRIDAY...IN THE HIGH 70S OVER SOME AREAS...DUE TO THE PRECIP MOVING INTO THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1145 AM MDT MON SEP 7 2015 LOW STRATUS/CIGS SHOULD INCREASE TO VFR BY THE MIDDLE OF THE AFTERNOON AT BOTH KGLD AND KMCK. VIS SATELLITE ALREADY SHOWING BACK EDGE OF STRATUS JUST SW OF KGLD AND THIS SHOULD CONTINUE TO THE NORTHEAST AS INDICATED BY SHORT RANGE GUIDANCE LOW LEVEL MOISTURE FIELDS. SHOWERS/THUNDERSTORMS ARE STILL POSSIBLE ACROSS THE AREA THIS AFTERNOON/EVENING WITH FRONT LINGERING JUST SOUTH OF KGLD AND ADDITIONAL UPPER LEVEL DISTURBANCES EXPECTED TO MOVE THROUGH REGION. HIGH RES GUIDANCE SHOWING A LULL IN ACTIVITY THIS AFTERNOON WITH ACTIVITY INCREASING IN COVERAGE THIS EVENING. AT THIS POINT CONFIDENCE WAS TOO LOW TO INCLUDE MENTION OF THUNDER IN TAFS BUT I DID KEEP VCSH IN PLACE. GUIDANCE SHOWING LOW STRATUS/FOG REDEVELOPING WITH LIGHT EAST/NORTHEAST FLOW OVER CENTRAL NEBRASKA AND ADVECTING TO THE SOUTHWEST OVER KMCK THEN KGLD...LINGERING THROUGH MID MORNING. THERE MAY BE A PERIOD OF LIFR VIS/CIG...HOWEVER CONFIDENCE IN PREVAILING CONDITIONS IS LEANING TOWARDS IFR VIS (1-2SM)BASED ON MODEL CONSENSUS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...CLT AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1155 PM CDT SUN SEP 6 2015 ...Update to aviation forecast discussion... .UPDATE... ISSUED AT 933 PM CDT SUN SEP 6 2015 Convective development in the local forecast area continues to struggle, but a rather strong model signal continues to indicate that elevated storms (similar to that currently seen in far southeast Nebraska) will develop into eastern KS as well tonight. It seems that for this to occur depends on the development of a cold pool from the ongoing storms. This currently exists near the Nebraska border, and if it can continue to be reinforced and pushed south than would expect at least scattered storms to develop overnight. If this happens, the severe weather threat is quite low but non-zero for wind/hail. Pockets of heavy rain also remain possible if these storms develop as there could be localized training, but dry ground conditions suggest the flash flood potential is quite low. && .SHORT TERM...(THIS EVENING THROUGH Monday) ISSUED AT 254 PM CDT SUN SEP 6 2015 Latest surface analysis had the frontal boundary from just east of Albion Nebraska to near Norton Kansas at 19Z. Surface temperatures ahead of the front across northeast Kansas have warmed to near the century mark in north central and northeast Kansas. Latest mesoanalysis along with latest RAP soundings show steep low level lapse rates and SBCAPE around 3000 J/kg this afternoon. Hires short term models have differing scenarios with regards to convective development, with the operational HRRR and the RAP the most robust with developing storms where the ARW, NMM and experimental HRRR showing less coverage across central and north central Kansas tonight. However most models continue to show a signal of a MCS developing across far northeast Kansas into southwest Iowa and northwest Missouri tonight and then moving it south southeast across eastern Kansas and western Missouri. The aforementioned frontal boundary will gradually move eastward tonight into the forecast area. Not sure exactly how far south the boundary will move tonight before lifting north again on Labor Day. Water vapor loop this afternoon shows moisture streaming from the eastern Pacific into the Central Plains. Southwesterly low level jet will advect high theta-e air into northeast Kansas overnight and should help to maintain the forward propagating MCS as well as contribute to high precipitation efficiency. On Labor day the front is expected to lift northward in response to an upper level trough moving eastward into the Northern and Central Plains to near or just north of the Nebraska and Kansas border in the afternoon. Left over boundaries from morning convection may focus isolated convection in the afternoon, but feel most areas will be dry until late afternoon along the Kansas and Nebraska border near the front. Effective shear tonight and Labor Day will be around 25 to 30 kts along with ample instability. If storms develop late this afternoon and early evening they will have the potential for damaging wind gusts and also again on Labor Day afternoon. There is also some potential for Hail as storms become elevated later tonight, but locally heavy rainfall will be the main concern. Lows tonight remain mild in the low to mid 70s and highs on Labor Day will be dependent on cloud cover. Feel there may be enough sunshine to send temps back into the lower 90s for most areas. .LONG TERM...(Monday NIGHT THROUGH Sunday) ISSUED AT 254 PM CDT SUN SEP 6 2015 Monday night through Wednesday...Synoptic scale boundary should extend from southeast Nebraska through north central KS by early Monday evening. As boundary sags slowly south over night, expect clusters of thunderstorms to develop along it and move east, with the best chance for heavier rainfall north of I70, and especially near and north of U.S. 36. Have highest POPs and most QPF for that area. On Tuesday, most short term models bring frontal boundary nearly through the forecast area, although outflow from thunderstorm complex makes it somewhat hard to place. Highest POPs should shift from northeast KS into far eastern, and especially east central KS during the afternoon. Thunderstorm activity near the front should shift out of east central KS during the evening. Would expect late Tuesday night and Wednesday to be dry as a ridge of surface high pressure builds in. Wednesday night through Sunday...Eastern KS remains in northwest flow aloft through Saturday. While gulf airmass should remain to our south, periodic disturbances in this northwest flow will result in chances for showers and thunderstorms. Cooler, more stable airmass over far northeast KS is expected to keep the best chance for convective activity over north central and parts of east central KS. Much cooler temperatures than we`ve had recently are expected for the latter part of the week into the weekend, with highs in the 70s to lower 80s, depending on how much sun is seen each afternoon. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Monday NIGHT) ISSUED AT 1152 PM CDT SUN SEP 6 2015 Another rather uncertain TAF concerning convective potential. Have maintained periods of VCTS to highlight the most likely timing of TS near TAF sites, but have not gone with prevailing TS as coverage is not likely to be widespread and confidence in development is on the lower end. Outside of thunderstorms, VFR conditions are likely through the TAF period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barjenbruch SHORT TERM...53 LONG TERM...GDP AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS JACKSON KY
132 PM EDT MON SEP 7 2015 .UPDATE... ISSUED AT 1248 PM EDT MON SEP 7 2015 HOURLY TEMPERATURES ACROSS THE AREA HAVE BEEN RUNNING SEVERAL DEGREES WARMER SO FAR TODAY THAN THE PREVIOUS FORECAST WAS DEPICTING. BASED ON THAT AND THE DELAY IN CLOUD FORMATION TODAY COMPARED TO YESTERDAY...DECIDED TO GO AHEAD AND INCREASE TEMPERATURES FOR MOST LOCATIONS ACROSS EASTERN KENTUCKY BY A COUPLE OF DEGREES. ALSO REMOVED OUTDATED WORDING FROM THE ZONE FORECAST TEXT PRODUCT. UPDATE ISSUED AT 1015 AM EDT MON SEP 7 2015 UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON WORDING AND ANY OTHER NECESSARY CHANGES. UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015 HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT. NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON SEP 7 2015 THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN. VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON. SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY. TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN. THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA. TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES TO CENTRAL PLAINS. ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL HOLD OFF UNTIL THE LONG TERM PERIOD. AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN DRY FOR THE VAST MAJORITY OF THE REGION. ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A MINOR RIDGE/VALLEY SPLIT FOR TONIGHT. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 407 AM EDT MON SEP 7 2015 THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME TO A END. THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE PAINTING SOMETHING SIMILAR. AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE UNCERTAIN PATTERN. THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 132 PM EDT MON SEP 7 2015 A RIDGE OF HIGH PRESSURE WILL CONTINUE TO INFLUENCE THE WEATHER OF EASTERN KENTUCKY DURING THE TAF PERIOD. SCATTERED TO BROKEN LOW LEVEL CUMULUS CLOUDS WILL PERSIST THROUGH THE REMAINDER OF THE DAY LIGHT HOURS...BEFORE DISSIPATING QUICKLY AFTER THE SUN GOES DOWN. ISOLATED SHOWERS AND STORMS ALONG AND WEST OF I-75 THIS AFTERNOON AND EVENING. SHOWERS AND STORMS WILL BE POSSIBLE ALONG THE TENNESSEE AND SOUTHWESTERN VIRGINIA BORDERS. THE ISOLATED NATURE OF THE PRECIPITATION SHOULD KEEP IT OUT OF THE TAF SITES AND LOZ AND SME. JKL...SYM...AND SJS SHOULD EXPERIENCE ONLY PARTLY CLOUDY SKIES THROUGH LATE THIS AFTERNOON. WITH CONDITIONS A BIT WARMER AND DRIER THAN YESTERDAY...FOG SHOULD BE A LITTLE BIT LESS WIDESPREAD OVERNIGHT. LOZ AND SME MAY STILL SEE SOME FOG DUE TO ANY RAINFALL THAT OCCURS TODAY WHICH COULD RESULT IN MVFR TO IFR CONDITIONS AT TIMES LATE TONIGHT. LOZ MAY EVEN SEE BRIEF PERIODS OF LIFR CIGS AS THE VALLEY FLOOR SATURATES. ASIDE FROM THAT...ANY FOG SHOULD BE CONFINED TO VALLEYS AND NEAR BODIES OF WATER. WINDS DURING THE PERIOD WILL BE LIGHT AND VARIABLE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...JP LONG TERM...DJ AVIATION...AR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
105 PM EDT MON SEP 7 2015 ...UPDATED AVIATION DISCUSSION... ...FORECAST UPDATE... ISSUED AT 1130 AM EDT MON SEP 7 2015 THE FORECAST IS ON TRACK FOR THIS AFTERNOON...WITH MAX TEMPS EXPECTED TO HIT THE LOW TO MID 90S. COMPARED TO 24 HOURS AGO...READINGS ARE ABOUT 1 TO 2 DEGREES WARMER SO FEEL CONFIDENT WE`LL HIT THE FORECAST HIGHS. WITH WEAK SHEAR AXIS OVERHEAD...AND WEAK SHORTWAVE RETROGRADING BACK INTO SOUTHEAST KENTUCKY...THE SLIGHT CHANCES OF SHOWERS/STORMS LOOK GOOD. RAP SOUNDINGS ARE SHOWING WARMER MID LEVEL TEMPERATURES COMPARED TO THE PAST FEW DAYS...WHICH SHOULD KEEP COVERAGE/INTENSITY TO A MINIMUM. .SHORT TERM (NOW THROUGH TUESDAY)... ISSUED AT 235 AM EDT MON SEP 7 2015 THE SYNOPTIC PATTERN EARLY THIS MORNING FEATURES A BROAD RIDGE ACROSS MUCH OF THE EASTERN CONUS...WITH A VERY BROAD/WEAK LOW CONTINUING TO SPIN BENEATH THE RIDGE OVER NORTHERN GEORGIA. A SHEAR AXIS NOTED ON THE NORTHWEST SIDE OF THIS LOW WILL BE THE MAIN FOCUS TODAY. LOOKING BACK TO THE CONVECTION YESTERDAY...IT WAS ALL SPARKED WITHIN THE SHEAR AXIS BETWEEN THE UPPER LOW TO THE SOUTHEAST AND THE AMPLIFIED RIDGE ACROSS THE GREAT LAKES/MIDWEST REGION. AREAS MAINLY EAST OF I-65 WILL ONCE AGAIN BE WITHIN THIS SHEAR AXIS TODAY THROUGH WHICH VERY SUBTLE UPPER-LEVEL WAVES WILL TRAVERSE AS THEY ROTATE AROUND THE UPPER LOW. FORECAST SOUNDINGS DO SHOW WARM AIR ALOFT MAINLY AROUND 650-700MB...BUT IT IS NOT ALL THAT MUCH STRONGER THAN YESTERDAY WHERE WE HAD SOME ISOLATED/WIDELY SCATTERED CONVECTION. MANY OF THE CAMS ARE ON BOARD WITH THE IDEA OF SOME VERY ISOLATED ACTIVITY TODAY AND THESE HAVE BEEN LEADING THE CHARGE WITH CONVECTIVE COVERAGE THE PAST FEW DAYS. THEREFORE...WILL GO WITH 15- 20% COVERAGE WITH THE BEST CHANCES EAST OF I-65 AND SOUTH OF I-64. LOW-LEVEL THICKNESSES REMAIN VERY SIMILIAR TO WHAT THEY`VE BEEN THE PAST FEW DAYS...SO BARRING ANY ENHANCED CLOUD COVER FROM CONVECTION...HIGHS FIRMLY INTO THE 90S LOOK LIKELY AGAIN TODAY. TONIGHT WILL BE MAINLY CLEAR AND MILD...WITH LOWS IN THE MID 60S TO LOWER 70S ONCE AGAIN. ON TUESDAY...THE UPPER LOW WILL BECOME LESS OF A PLAYER AS IT MOVES OFF TO THE SOUTHWEST. ADDITIONALLY...THE CAPPING TOMORROW LOOKS SUBSTANTIALLY STRONGER THAN IT DOES TODAY. THEREFORE...WILL GO WITH A DRY FORECAST AND A PERSISTENCE FORECAST FOR HIGH TEMPERATURES. .LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)... ISSUED AT 305 AM EDT MON SEP 7 2015 STILL LOOKING AT A TROUGH MOVING ACROSS THE REGION WEDNESDAY/WEDNESDAY NIGHT. THE QUESTION IS HOW MUCH PRECIPITATION WILL MOVE INTO THE REGION WEDNESDAY MORNING AHEAD OF IT. LOOKS LIKE SOME STORMS WILL FORM OVER MO/IL EARLY WEDNESDAY AND THESE MAY PUSH INTO OUR NORTHWEST COUNTIES AROUND DAYBREAK. THEY COULD BRING CLOUDINESS THROUGH THE DAY...DELAYING THE ONSET OF NEW AFTERNOON STORMS UNTIL LATER IN THE DAY AND BRINGING TEMPERATURES DOWN. SHOULD THESE STORMS DIE OFF QUICKER THAN IN THIS FORECAST...THEN WE WOULD SEE A LITTLE WARMER AFTERNOON HIGHS AND AN EARLIER ONSET OF STORM DEVELOPMENT. FOR NOW WILL CALL FOR AFTERNOON HIGHS IN THE 80S...BREAKING OUR 90+ DEGREE STRING TO START SEPTEMBER. AS FOR SEVERITY OF THESE STORMS...MODEL WIND FIELDS ARE NOT OVERLY IMPRESSIVE. THINK THE STRONGER GUSTS WOULD COME WITH THE LATTER SCENARIO GIVEN ABOVE. WILL CONTINUE TO MENTION BRIEF GUSTY WINDS IN THE HWO. ANOTHER WEAKER SHORTWAVE LOOKS TO MOVE THROUGH THE REGION THURSDAY...CONTINUING THE CHANCE FOR RAIN...WITH THE BEST CHANCE IN OUR SOUTHEAST. FRIDAY CONTINUES TO TREND DRIER...BUT WITH ANOTHER WAVE CROSS ING THE REGION CANNOT RULE OUT SOME DEVELOPMENT AT LEAST EAST OF I-65. AFTER THAT WE SHOULD BE TOO DRY FOR FURTHER DEVELOPMENT THIS WEEKEND...AND TEMPERATURES WILL BE QUITE PLEASANT...WITH HIGHS IN THE 70S SATURDAY AND AROUND 80 SUNDAY. && .AVIATION (18Z TAF UPDATE)... ISSUED AT 105 PM EDT MON SEP 7 2015 PLAN ON VFR CONDITIONS THE REMAINDER OF TODAY AT ALL TAF SITES AS HIGH PRESSURE AT THE SURFACE AND ALOFT PROVIDES HOT AND DRY CONDITIONS TO THE AREA. WINDS WILL BE LIGHT/VARIABLE. FOG WILL ONCE AGAIN BE A THREAT OVERNIGHT...PARTICULARLY AT BWG WHERE MVFR RESTRICTIONS ARE EXPECTED. LOWER CONDITIONS WILL BE POSSIBLE IF ISOLATED TO SCATTERED STORMS DEVELOP NEAR THE TERMINAL...OTHERWISE THINK THAT A DAY OF DRYING SHOULD KEEP VISIBILITY FROM DROPPING TOO FAR. FOR TUESDAY...PLAN ON ONE MORE DRY AND HOT DAY FOR THE REGION BEFORE A PATTERN CHANGE AND SHOWERS/STORMS RETURN MID-WEEK. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ UPDATE.........ZBT SHORT TERM.....KJD LONG TERM......RJS AVIATION.......ZBT
AREA FORECAST DISCUSSION
NWS JACKSON KY
1249 PM EDT MON SEP 7 2015 .UPDATE... ISSUED AT 1248 PM EDT MON SEP 7 2015 HOURLY TEMPERATURES ACROSS THE AREA HAVE BEEN RUNNING SEVERAL DEGREES WARMER SO FAR TODAY THAN THE PREVIOUS FORECAST WAS DEPICTING. BASED ON THAT AND THE DELAY IN CLOUD FORMATION TODAY COMPARED TO YESTERDAY...DECIDED TO GO AHEAD AND INCREASE TEMPERATURES FOR MOST LOCATIONS ACROSS EASTERN KENTUCKY BY A COUPLE OF DEGREES. ALSO REMOVED OUTDATED WORDING FROM THE ZONE FORECAST TEXT PRODUCT. UPDATE ISSUED AT 1015 AM EDT MON SEP 7 2015 UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON WORDING AND ANY OTHER NECESSARY CHANGES. UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015 HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT. NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON SEP 7 2015 THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN. VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON. SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY. TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN. THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA. TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES TO CENTRAL PLAINS. ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL HOLD OFF UNTIL THE LONG TERM PERIOD. AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN DRY FOR THE VAST MAJORITY OF THE REGION. ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A MINOR RIDGE/VALLEY SPLIT FOR TONIGHT. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 407 AM EDT MON SEP 7 2015 THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME TO A END. THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE PAINTING SOMETHING SIMILAR. AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE UNCERTAIN PATTERN. THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 735 AM EDT MON SEP 7 2015 A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES. MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME... IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z. A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN NEAR THE END OF THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...JP LONG TERM...DJ AVIATION...JP
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1133 AM EDT MON SEP 7 2015 ...FORECAST UPDATE... ISSUED AT 1130 AM EDT MON SEP 7 2015 THE FORECAST IS ON TRACK FOR THIS AFTERNOON...WITH MAX TEMPS EXPECTED TO HIT THE LOW TO MID 90S. COMPARED TO 24 HOURS AGO...READINGS ARE ABOUT 1 TO 2 DEGREES WARMER SO FEEL CONFIDENT WE`LL HIT THE FORECAST HIGHS. WITH WEAK SHEAR AXIS OVERHEAD...AND WEAK SHORTWAVE RETROGRADING BACK INTO SOUTHEAST KENTUCKY...THE SLIGHT CHANCES OF SHOWERS/STORMS LOOK GOOD. RAP SOUNDINGS ARE SHOWING WARMER MID LEVEL TEMPERATURES COMPARED TO THE PAST FEW DAYS...WHICH SHOULD KEEP COVERAGE/INTENSITY TO A MINIMUM. .SHORT TERM (NOW THROUGH TUESDAY)... ISSUED AT 235 AM EDT MON SEP 7 2015 THE SYNOPTIC PATTERN EARLY THIS MORNING FEATURES A BROAD RIDGE ACROSS MUCH OF THE EASTERN CONUS...WITH A VERY BROAD/WEAK LOW CONTINUING TO SPIN BENEATH THE RIDGE OVER NORTHERN GEORGIA. A SHEAR AXIS NOTED ON THE NORTHWEST SIDE OF THIS LOW WILL BE THE MAIN FOCUS TODAY. LOOKING BACK TO THE CONVECTION YESTERDAY...IT WAS ALL SPARKED WITHIN THE SHEAR AXIS BETWEEN THE UPPER LOW TO THE SOUTHEAST AND THE AMPLIFIED RIDGE ACROSS THE GREAT LAKES/MIDWEST REGION. AREAS MAINLY EAST OF I-65 WILL ONCE AGAIN BE WITHIN THIS SHEAR AXIS TODAY THROUGH WHICH VERY SUBTLE UPPER-LEVEL WAVES WILL TRAVERSE AS THEY ROTATE AROUND THE UPPER LOW. FORECAST SOUNDINGS DO SHOW WARM AIR ALOFT MAINLY AROUND 650-700MB...BUT IT IS NOT ALL THAT MUCH STRONGER THAN YESTERDAY WHERE WE HAD SOME ISOLATED/WIDELY SCATTERED CONVECTION. MANY OF THE CAMS ARE ON BOARD WITH THE IDEA OF SOME VERY ISOLATED ACTIVITY TODAY AND THESE HAVE BEEN LEADING THE CHARGE WITH CONVECTIVE COVERAGE THE PAST FEW DAYS. THEREFORE...WILL GO WITH 15- 20% COVERAGE WITH THE BEST CHANCES EAST OF I-65 AND SOUTH OF I-64. LOW-LEVEL THICKNESSES REMAIN VERY SIMILIAR TO WHAT THEY`VE BEEN THE PAST FEW DAYS...SO BARRING ANY ENHANCED CLOUD COVER FROM CONVECTION...HIGHS FIRMLY INTO THE 90S LOOK LIKELY AGAIN TODAY. TONIGHT WILL BE MAINLY CLEAR AND MILD...WITH LOWS IN THE MID 60S TO LOWER 70S ONCE AGAIN. ON TUESDAY...THE UPPER LOW WILL BECOME LESS OF A PLAYER AS IT MOVES OFF TO THE SOUTHWEST. ADDITIONALLY...THE CAPPING TOMORROW LOOKS SUBSTANTIALLY STRONGER THAN IT DOES TODAY. THEREFORE...WILL GO WITH A DRY FORECAST AND A PERSISTENCE FORECAST FOR HIGH TEMPERATURES. .LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)... ISSUED AT 305 AM EDT MON SEP 7 2015 STILL LOOKING AT A TROUGH MOVING ACROSS THE REGION WEDNESDAY/WEDNESDAY NIGHT. THE QUESTION IS HOW MUCH PRECIPITATION WILL MOVE INTO THE REGION WEDNESDAY MORNING AHEAD OF IT. LOOKS LIKE SOME STORMS WILL FORM OVER MO/IL EARLY WEDNESDAY AND THESE MAY PUSH INTO OUR NORTHWEST COUNTIES AROUND DAYBREAK. THEY COULD BRING CLOUDINESS THROUGH THE DAY...DELAYING THE ONSET OF NEW AFTERNOON STORMS UNTIL LATER IN THE DAY AND BRINGING TEMPERATURES DOWN. SHOULD THESE STORMS DIE OFF QUICKER THAN IN THIS FORECAST...THEN WE WOULD SEE A LITTLE WARMER AFTERNOON HIGHS AND AN EARLIER ONSET OF STORM DEVELOPMENT. FOR NOW WILL CALL FOR AFTERNOON HIGHS IN THE 80S...BREAKING OUR 90+ DEGREE STRING TO START SEPTEMBER. AS FOR SEVERITY OF THESE STORMS...MODEL WIND FIELDS ARE NOT OVERLY IMPRESSIVE. THINK THE STRONGER GUSTS WOULD COME WITH THE LATTER SCENARIO GIVEN ABOVE. WILL CONTINUE TO MENTION BRIEF GUSTY WINDS IN THE HWO. ANOTHER WEAKER SHORTWAVE LOOKS TO MOVE THROUGH THE REGION THURSDAY...CONTINUING THE CHANCE FOR RAIN...WITH THE BEST CHANCE IN OUR SOUTHEAST. FRIDAY CONTINUES TO TREND DRIER...BUT WITH ANOTHER WAVE CROSS ING THE REGION CANNOT RULE OUT SOME DEVELOPMENT AT LEAST EAST OF I-65. AFTER THAT WE SHOULD BE TOO DRY FOR FURTHER DEVELOPMENT THIS WEEKEND...AND TEMPERATURES WILL BE QUITE PLEASANT...WITH HIGHS IN THE 70S SATURDAY AND AROUND 80 SUNDAY. && .AVIATION (12Z TAF UPDATE)... ISSUED AT 640 AM EDT MON SEP 7 2015 AFTER SOME MORNING FOG AT KBWG AND PERHAPS SOME LIGHT FOG AT KLEX...CONDITIONS WILL RETURN TO VFR THROUGH TODAY AND INTO TONIGHT. CAN`T RULE OUT A STRAY STORM THIS AFTERNOON MAINLY AT KLEX OR KBWG...BUT COVERAGE WILL BE RATHER SPARSE SO WILL NOT INCLUDE ANY MENTION IN THE FORECAST. OTHERWISE...EXPECT JUST SOME AFTERNOON CU WITH GENERALLY LIGHT WINDS. FOG WILL ONCE AGAIN BE POSSIBLE TONIGHT AS WE REMAIN IN A SIMILAR PATTERN. THUS WILL INTRODUCE MVFR VSBYS ONCE AGAIN TO KBWG AND KLEX FOR FOG NEAR SUNRISE TUESDAY. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ UPDATE.........ZBT SHORT TERM.....KJD LONG TERM......RJS AVIATION.......KJD
AREA FORECAST DISCUSSION
NWS JACKSON KY
1016 AM EDT MON SEP 7 2015 .UPDATE... ISSUED AT 1015 AM EDT MON SEP 7 2015 UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON WORDING AND ANY OTHER NECESSARY CHANGES. UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015 HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT. NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON SEP 7 2015 THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN. VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON. SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY. TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN. THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA. TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES TO CENTRAL PLAINS. ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL HOLD OFF UNTIL THE LONG TERM PERIOD. AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN DRY FOR THE VAST MAJORITY OF THE REGION. ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A MINOR RIDGE/VALLEY SPLIT FOR TONIGHT. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 407 AM EDT MON SEP 7 2015 THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME TO A END. THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE PAINTING SOMETHING SIMILAR. AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE UNCERTAIN PATTERN. THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 735 AM EDT MON SEP 7 2015 A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES. MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME... IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z. A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN NEAR THE END OF THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...JP LONG TERM...DJ AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
737 AM EDT MON SEP 7 2015 .UPDATE... ISSUED AT 730 AM EDT MON SEP 7 2015 HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT. NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON SEP 7 2015 THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN. VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON. SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY. TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN. THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA. TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES TO CENTRAL PLAINS. ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL HOLD OFF UNTIL THE LONG TERM PERIOD. AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN DRY FOR THE VAST MAJORITY OF THE REGION. ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A MINOR RIDGE/VALLEY SPLIT FOR TONIGHT. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 407 AM EDT MON SEP 7 2015 THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME TO A END. THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE PAINTING SOMETHING SIMILAR. AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE UNCERTAIN PATTERN. THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 735 AM EDT MON SEP 7 2015 A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES. MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME... IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z. A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN NEAR THE END OF THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...JP LONG TERM...DJ AVIATION...JP
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1102 PM EDT TUE SEP 8 2015 .SYNOPSIS... A WARM FRONT WILL PUSH THROUGH THE REGION OVERNIGHT BRINGING A BAND OF RAIN SHOWERS. TOMORROW AFTERNOON A WEAK COLD FRONT WILL PUSH THROUGH THE AREA...BRINGING ANOTHER ROUNDS OF SHOWERS AND ISOLATED THUNDERSTORMS. SMALL BREAK IN THE WEATHER ON THURSDAY...BEFORE A COASTAL LOW PRESSURE SYSTEM BRINGS WIDESPREAD HEAVY RAIN TO THE COAST THURSDAY NIGHT INTO FRIDAY. && .NEAR TERM /THROUGH WEDNESDAY/... 1025 PM UPDATE: ADJUSTED THE POPS TO BUT PERCENTAGE BACK INITIALLY AS BEST ACTIVITY IS STILL WELL W OF THE CWA. DECIDED TO PUSH BACK THE TIMING BY 3HRS USING THE LATEST HRRR 3KM MODEL FOR INITIALIZATION. CLOUDS WILL FILL BACK IN LATER IN THE NIGHT AS THE WARM FRONT LIFTS N. HRLY TEMPS WERE ADJUSTED AS WELL TO MATCH UP WITH THE LATEST CONDITIONS AND THEREFORE, TWEAKED THE OVERNIGHT MINS ESPECIALLY ACROSS THE EASTERN AREAS. OVERNIGHT, THE WARM UNSTABLE AIRMASS TO THE SOUTH BEGINS TO PUSH NORTH ONCE AGAIN AS A WARM FRONT ASSOCIATED WITH AN AREA OF LOW PRESSURE PUSHING THROUGH QUEBEC PROVINCE. SHOWERS AND EVEN AN ISOLATED THUNDERSTORM WILL DEVELOP TONIGHT AND PUSH FROM SOUTH TO NORTH ALONG THE BOUNDARY. OVERALL QPF AMOUNTS WILL REMAIN RELATIVELY LIGHT WITH LESS THEN .25" FOR MOST AREAS...COULD BE LOCALLY HIGHER AMOUNTS IN THE CENTRAL HIGHLANDS. DURING THE DAY ON WEDNESDAY IT WILL BE HUMID ONCE AGAIN WITH DEWPOINT TEMPS WELL INTO THE 60S...WITH A FEW PLACES IN PENOBSCOT TOUCHING 70. PARTIAL CLEARING IS LIKELY ACROSS DOWNEAST TOMORROW MORNING...BUT WILL STAY MOSTLY CLOUDY ACROSS THE CROWN OF MAINE. AFTER A SMALL BREAK A WEAK COLD FRONT WILL PUSH INTO THE REGION LATE WEDNESDAY AFTERNOON/EARLY EVENING. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED ONCE AGAIN WITH THIS BOUNDARY. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... A COLD FRONT WILL BE DRAPED ACROSS OUR CWA AT THE START OF WEDNESDAY NIGHT...THEN GRADUALLY SINK SOUTH AND BECOME STATIONARY ALONG THE COAST BY THURSDAY. A LOW PRESSURE SYSTEM WILL THEN DEVELOP ACROSS THE MID-ATLANTIC REGION AND THEN LIFT NEWD ACROSS NEW ENGLAND THURSDAY NIGHT AND FRIDAY. STRONG UVV COMBINED WITH HIGH PWAT VALUES WILL CREATE THE CHANCE FOR HEAVY RAINFALL ACROSS OUR DOWNEAST ZONES...ESPECIALLY LATE THURSDAY AND FRIDAY MORNING. WE HAVE GONE WITH A BLEND OF THE NAM12/GFS40/06Z ECMWF FOR OUR PRECIP AMOUNTS...WHICH RESULTS IN STORM TOTAL VALUES OF UP TO 2 INCHES DOWNEAST. AS A RESULT...WE WILL MENTION THAT HEAVY RAINFALL IS POSSIBLE DURING THIS TIME FRAME. TEMPERATURES WILL REMAIN SEASONABLY WARM WITH HIGHS GENERALLY IN THE LOW TO MID 70S DURING THE SHORT TERM. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT WEEK. WE`LL GET A BRIEF DRY SPELL SATURDAY WITH WEAK RIDGING, BUT THEN AN UPPER LOW DIGGING INTO THE UPPER MIDWEST WILL BRING THE CHANCES FOR MORE RAIN SUNDAY AND MONDAY. AS USUAL, THE LONG RANGE MODELS DIFFER ON THE EXACT HANDLING OF THIS FEATURE ALONG WITH ITS SURFACE REFLECTIONS. THIS MEANS THERE`S DISCREPANCIES ON WHERE THE PRECIPITATION SETS UP AND HOW HEAVY IT`LL BE. HAVE GONE WITH MAINLY SLIGHT CHANCE/LOW CHANCE POPS TO ACCOUNT FOR MODEL DIFFERENCES. HIGH PRESSURE LOOKS TO SET BACK IN FOR TUESDAY. TEMPERATURES WILL REMAIN A BIT ABOVE NORMAL, BUT NOT NEARLY TO THE EXTENT WE`VE SEEN OVER THE PAST FEW DAYS. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: IFR CONDITIONS ARE EXPECTED TONIGHT AS A WARM MOIST AIRMASS PUSHES INTO THE REGION. SOME RAIN SHOWERS AND A ISOLATED THUNDERSTORM IS POSSIBLE AS A WARM FRONT PUSHES THROUGH THE ARE TONIGHT. CONDITIONS WILL BEGIN TO IMPROVE TOMORROW MORNING WITH GUSTY SOUTHERLY WINDS. SHORT TERM: MVFR/IFR CIGS AND VSBYS ARE LIKELY ACROSS OUR CWA DURING THE SHORT TERM FORECAST PERIOD WITH A FRONT MOVING THROUGH EARLY AND THEN A LOW POSSIBLE BRINGING HEAVY RAIN TO THE AREA ON THURSDAY NIGHT AND FRIDAY. && .MARINE... NEAR TERM: WINDS AND SEAS ARE EXPECTED TO STAY BELOW SCA TONIGHT AND TOMORROW. WINDS WILL SHIFT FROM OFF SHORE TONIGHT TO ONSHORE AND INCREASE IN SPEED THROUGH THE DAY. SHORT TERM: WINDS AND SEAS ARE EXPECTED TO STAY BELOW SCA CRITERIA WEDNESDAY NIGHT THROUGH FRIDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
932 PM EDT TUE SEP 8 2015 .SYNOPSIS... HIGH PRESSURE WILL SLIDE OFF THE MID ATLANTIC COAST TONIGHT THROUGH WEDNESDAY. A COLD FRONT APPROACHES FROM THE NORTHWEST WEDNESDAY...AND SETTLES INTO THE REGION THURSDAY. THE FRONT STALLS OVER NORTH CAROLINA FRIDAY INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... UPDATE...SHOWERS ACROSS INTERIOR NE NC ARE FINALLY TAPERING OFF LATE THIS EVENING AND A LULL IN ACTIVITY IS EXPECTED DURING THE REST OF THE EVENING AND EARLY OVERNIGHT HOURS. PREVIOUS DISCUSSION...PER LATEST RAP GUIDANCE...WEAK VORT MAX LIFTS NEWD OVER ERN VA TONIGHT. HI-RES GUIDANCE INDICATES THE WARM/MOIST AND MODESTLY UNSTABLE AIR MASS MAY PRODUCE SOME ISOLATED SHOWERS OVERNIGHT ACROSS CENTRAL AND ERN VA AS THE VORT LIFTS...ESPECIALLY OVER THE BAY AND ERN SHORE. HOWEVER... CONFIDENCE IS NOT HIGH ATTM...SO WILL LEAVE SLIGHT CHANCE WORDING. A PARTLY CLOUDY SKY AND DISPERSAL WILL LIMIT FOG DEVELOPMENT TONIGHT...BUT WARM/SOUPY AIR MASS SHOULD BE ENOUGH FOR PATCHY FOG IN AREAS THAT RECEIVED RAINFALL EARLIER TODAY. A MILD TONIGHT AHEAD WITH LOWS IN THE LOW 70S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... UPPER TROUGH DIGS OVER THE GREAT LAKES REGION WEDS AND THU...RESULTING IN HEIGHT FALLS OVER THE MID-ATLANTIC REGION. AN ASSOCIATED COLD FRONT IS EXPECTED TO REACH THE OHIO VALLEY BY WEDS AFTERNOON. LEE/THERMAL TROUGH DEVELOPS OVER THE PIEDMONT IN ADVANCE OF THE FRONT WEDS AFTERNOON. INCREASING SW FLOW WILL ADVECT DEEP LAYERED MOISTURE INTO THE REGION...WITH PWATS PROGGED AOA 2 INCHES (+1 TO +2 STD DEV). WHILE THE MAIN SHEARING VORT ENERGY REMAINS OVER THE OHIO VALLEY...WEAK PERTURBATIONS IN THE SW FLOW WILL PROVIDE SUBTLE FORCING FOR ASCENT OVER THE LOCAL AREA. THETA-E ADVECTION AND DEWPOINTS IN THE LOW 70S WILL RESULT IN BETTER INSTABILITY...WITH MLCAPE ~1500 J/KG. HAVE FAVORED THE PIEDMONT INTO CENTRAL AND EAST CENTRAL VA FOR 30-40 PCT POPS. WARMER TEMPS ALOFT ACROSS THE SE WILL LIMIT OVERALL COVERAGE...SO HAVE CAPPED AT 30 PCT. EFFECTIVE SHEAR PROGGED AROUND 15 TO 20 KT MAY RESULT IN SLIGHT BETTER ORGANIZATION...BUT SEVERE WEATHER IS NOT ANTICIPATED. WARM AND HUMID CONDITIONS PERSIST...WITH HIGHS FORECAST IN THE UPPER 80S TO AROUND 90 (MID 80S ALONG THE COAST). SLIGHT CHANCE TO CHANCE POPS WILL BE MAINTAINED THROUGH WEDNESDAY NIGHT. MILD AGAIN...WITH LOWS IN THE LOW/MID 70S. THE FLOW CONTINUES TO AMPLIFY OVER THE GREAT LAKES AND ERN CONUS THURSDAY AS SHORTWAVE ENERGY REACHES THE MID-ATLANTIC STATES. SFC LOW DEVELOPS ALONG THE FRONT THU MORNING...LIFTING OVER NRN VA INTO THE DELMARVA THU AFTERNOON AND EVENING. EXPECT WIDESPREAD...BENEFICIAL RAINFALL THURSDAY AFTERNOON. A WARM/MOIST AIR MASS REMAINS IN PLACE...BUT INSTABILITY WILL BE LIMITED DUE TO CLOUD COVER AND PRECIP. HAVE RETAINED LIKELY POPS ACROSS ALL BUT THE FAR SE LOCAL AREA. LACK OF ORGANIZED FORCING AND ANOMALOUS FLOW WILL KEEP OVERALL QPF AOB ONE HALF OF AN INCH. WEAK FLOW AND MBE/CORFIDI VECTORS FAVOR LOCALLY HIGHER AMOUNTS. CLOUDS/PRECIP AND HEIGHT/THICKNESS FALLS YIELD TEMPS RANGING FROM THE LOW 80S NW TO UPPER 80S SE. THE FRONT STALLS ALONG THE COAST THU NIGHT AND FRI IN SWLY FLOW ALOFT. BEST MOISTURE AND SHORTWAVE ENERGY LOCATES OVER THE COASTAL PLAIN...AND WILL RETAIN CHANCE POPS ACROSS SOUTHERN VA AND SE VA/NE NC. MORE SEASONABLE CONDITIONS EXPECTED FRI WITH HIGHS IN THE LOW TO MID 80S AND DEWPOINTS COOLING INTO THE LOW 60S NW TO UPPER 60S SE. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MODELS CONT TO STRUGGLE WITH A SOLN TO JUST HOW FAR EAST THE FRNTL BNDRY GETS THIS WEEKEND AS IT APPRCHS THE OFFSHORE RIDGE. CONSENSUS IS THAT IT STALLS RIGHT ALONG THE COAST AS SVRL WAVES OF LOW PRS MOVE NE ALONG IT. IN ADDITION...A RTHR POTENT UPR LVL SYSTM PROGGED TO DIVE SE FROM THE GT LAKE RGN LATER THIS WEEKEND. GFS STILL FRTHER SOUTH...BUT IT IS STARTING TO COME IN LINE WITH THE ECMWF SOLN OF SWING THE UPR LVL LOW NORTH OF FA WITH MOST OF THE ENERGY FROM THE VA MTS ON NORTH. APPEARS HIGH PRS MOVG EAST FROM NATIONS MID SECTION WILL BE STRNG ENUF TO PUSH THE ENTIRE SYSTM OFFSHORE ERLY NEXT WK. GIVEN THE ABOVE UNCERTAINTY...WILL KEEP A CONSISTENT FCST AND LEAN MORE TOWARD A ECMWF SOLN. KEPT CHC POPS FRI NITE THRU SUN NITE (HIGHEST POPS ALONG THE COAST AND MENTION THUNDER IN THE IN AFTN AND EVE). DRY MON/TUE. A COOLING TREND THRU THE PRD. HIGHS SAT 80- 85...COOLER AT THE BEACHES. LOWS 60-65. HIGHS SUN/MON 75-80. LOWS M50S-L60S. HIGHS TUE U70S-L80S. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... VFR CONDS ACROSS THE REGION AND TAF SITES WITH NO STORMS IN THE CWA. SATELLITE SHOWING GENERAL CLEARING. WINDS ARE MOSTLY LIGHT FROM THE SE LESS THAN 10 KT. SOME FOG POSSIBLE DURING THE OVERNIGHT BUT GUIDANCE AND SNDGS NOT SHOWING ANYTHING OF SIGNIFICANCE. THERE WILL BE A CHANCE OF SHRAS/TSTMS FM WED THRU FRI AS A COLD FRNT APPROACHES FM THE W AND STALLS IN THE VICINITY. && .MARINE... NO HEADLINES XPCT AS HIGH PRS MOVES OFFSHORE RESULTING IN A RETURN SLY FLOW THRU THURSDAY. ONCE AGAIN...HIGH RES DATA SUGGESTS SOME CHANNELING UP THE BAY AT NIGHT...SO KEPT SPEEDS AOB 15 KTS FOR NOW. COLD FRONT APPRCHS THE AREA THURSDAY AFTN THEN CROSSES THE WTRS THURSDAY NIGHT BEFORE STALLING JUST OFF THE COAST FRIDAY. LACK OF CAA BEHIND THE FRONT WILL KEEP SUB-SCA CNDTNS INTO FRIDAY. LOCATION OF FRONT INTO THE WEEKEND WILL BE KEY TO THE FCST. RIGHT NOW THE BNDRY LOOKS TO STRADDLE THE COAST KEEPING WNDS IN A GNRL WEST DRCTN AT SPEEDS ARND 10 KTS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ/SAM NEAR TERM...AJZ/BMD/SAM SHORT TERM...AJZ/SAM LONG TERM...MPR AVIATION...DAP/JEF MARINE...MPR
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
922 PM EDT TUE SEP 8 2015 .SYNOPSIS... HIGH PRESSURE WILL SLIDE OFF THE MID ATLANTIC COAST TONIGHT THROUGH WEDNESDAY. A COLD FRONT APPROACHES FROM THE NORTHWEST WEDNESDAY...AND SETTLES INTO THE REGION THURSDAY. THE FRONT STALLS OVER NORTH CAROLINA FRIDAY INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... UPDATE...SHOWERS ACROSS INTERIOR NE NC ARE FINALLY TAPERING OFF LATE THIS EVENING AND A LULL IN ACTIVITY IS EXPECTED DURING THE REST OF THE EVENING AND EARLY OVERNIGHT HOURS. PREVIOUS DISCUSSION...PER LATEST RAP GUIDANCE...WEAK VORT MAX LIFTS NEWD OVER ERN VA TONIGHT. HI-RES GUIDANCE INDICATES THE WARM/MOIST AND MODESTLY UNSTABLE AIR MASS MAY PRODUCE SOME ISOLATED SHOWERS OVERNIGHT ACROSS CENTRAL AND ERN VA AS THE VORT LIFTS...ESPECIALLY OVER THE BAY AND ERN SHORE. HOWEVER... CONFIDENCE IS NOT HIGH ATTM...SO WILL LEAVE SLIGHT CHANCE WORDING. A PARTLY CLOUDY SKY AND DISPERSAL WILL LIMIT FOG DEVELOPMENT TONIGHT...BUT WARM/SOUPY AIR MASS SHOULD BE ENOUGH FOR PATCHY FOG IN AREAS THAT RECEIVED RAINFALL EARLIER TODAY. A MILD TONIGHT AHEAD WITH LOWS IN THE LOW 70S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... UPPER TROUGH DIGS OVER THE GREAT LAKES REGION WEDS AND THU...RESULTING IN HEIGHT FALLS OVER THE MID-ATLANTIC REGION. AN ASSOCIATED COLD FRONT IS EXPECTED TO REACH THE OHIO VALLEY BY WEDS AFTERNOON. LEE/THERMAL TROUGH DEVELOPS OVER THE PIEDMONT IN ADVANCE OF THE FRONT WEDS AFTERNOON. INCREASING SW FLOW WILL ADVECT DEEP LAYERED MOISTURE INTO THE REGION...WITH PWATS PROGGED AOA 2 INCHES (+1 TO +2 STD DEV). WHILE THE MAIN SHEARING VORT ENERGY REMAINS OVER THE OHIO VALLEY...WEAK PERTURBATIONS IN THE SW FLOW WILL PROVIDE SUBTLE FORCING FOR ASCENT OVER THE LOCAL AREA. THETA-E ADVECTION AND DEWPOINTS IN THE LOW 70S WILL RESULT IN BETTER INSTABILITY...WITH MLCAPE ~1500 J/KG. HAVE FAVORED THE PIEDMONT INTO CENTRAL AND EAST CENTRAL VA FOR 30-40 PCT POPS. WARMER TEMPS ALOFT ACROSS THE SE WILL LIMIT OVERALL COVERAGE...SO HAVE CAPPED AT 30 PCT. EFFECTIVE SHEAR PROGGED AROUND 15 TO 20 KT MAY RESULT IN SLIGHT BETTER ORGANIZATION...BUT SEVERE WEATHER IS NOT ANTICIPATED. WARM AND HUMID CONDITIONS PERSIST...WITH HIGHS FORECAST IN THE UPPER 80S TO AROUND 90 (MID 80S ALONG THE COAST). SLIGHT CHANCE TO CHANCE POPS WILL BE MAINTAINED THROUGH WEDNESDAY NIGHT. MILD AGAIN...WITH LOWS IN THE LOW/MID 70S. THE FLOW CONTINUES TO AMPLIFY OVER THE GREAT LAKES AND ERN CONUS THURSDAY AS SHORTWAVE ENERGY REACHES THE MID-ATLANTIC STATES. SFC LOW DEVELOPS ALONG THE FRONT THU MORNING...LIFTING OVER NRN VA INTO THE DELMARVA THU AFTERNOON AND EVENING. EXPECT WIDESPREAD...BENEFICIAL RAINFALL THURSDAY AFTERNOON. A WARM/MOIST AIR MASS REMAINS IN PLACE...BUT INSTABILITY WILL BE LIMITED DUE TO CLOUD COVER AND PRECIP. HAVE RETAINED LIKELY POPS ACROSS ALL BUT THE FAR SE LOCAL AREA. LACK OF ORGANIZED FORCING AND ANOMALOUS FLOW WILL KEEP OVERALL QPF AOB ONE HALF OF AN INCH. WEAK FLOW AND MBE/CORFIDI VECTORS FAVOR LOCALLY HIGHER AMOUNTS. CLOUDS/PRECIP AND HEIGHT/THICKNESS FALLS YIELD TEMPS RANGING FROM THE LOW 80S NW TO UPPER 80S SE. THE FRONT STALLS ALONG THE COAST THU NIGHT AND FRI IN SWLY FLOW ALOFT. BEST MOISTURE AND SHORTWAVE ENERGY LOCATES OVER THE COASTAL PLAIN...AND WILL RETAIN CHANCE POPS ACROSS SOUTHERN VA AND SE VA/NE NC. MORE SEASONABLE CONDITIONS EXPECTED FRI WITH HIGHS IN THE LOW TO MID 80S AND DEWPOINTS COOLING INTO THE LOW 60S NW TO UPPER 60S SE. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MODELS CONT TO STRUGGLE WITH A SOLN TO JUST HOW FAR EAST THE FRNTL BNDRY GETS THIS WEEKEND AS IT APPRCHS THE OFFSHORE RIDGE. CONSENSUS IS THAT IT STALLS RIGHT ALONG THE COAST AS SVRL WAVES OF LOW PRS MOVE NE ALONG IT. IN ADDITION...A RTHR POTENT UPR LVL SYSTM PROGGED TO DIVE SE FROM THE GT LAKE RGN LATER THIS WEEKEND. GFS STILL FRTHER SOUTH...BUT IT IS STARTING TO COME IN LINE WITH THE ECMWF SOLN OF SWING THE UPR LVL LOW NORTH OF FA WITH MOST OF THE ENERGY FROM THE VA MTS ON NORTH. APPEARS HIGH PRS MOVG EAST FROM NATIONS MID SECTION WILL BE STRNG ENUF TO PUSH THE ENTIRE SYSTM OFFSHORE ERLY NEXT WK. GIVEN THE ABOVE UNCERTAINTY...WILL KEEP A CONSISTENT FCST AND LEAN MORE TOWARD A ECMWF SOLN. KEPT CHC POPS FRI NITE THRU SUN NITE (HIGHEST POPS ALONG THE COAST AND MENTION THUNDER IN THE IN AFTN AND EVE). DRY MON/TUE. A COOLING TREND THRU THE PRD. HIGHS SAT 80- 85...COOLER AT THE BEACHES. LOWS 60-65. HIGHS SUN/MON 75-80. LOWS M50S-L60S. HIGHS TUE U70S-L80S. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... AMPLE DEEP LAYER MOISTURE AND INSTABILITY HAVE HELPED INITIATE SHOWERS AND THUNDERSTORMS ALONG A WEAK AREA OF LOW PRESSURE ACROSS NE NC/SE VA. STORMS WILL PROGRESS NW ALONG A GUST FRONT BOUNDARY. EXPECT REDUCED VIS AND AND GUSTS TO ~20KT DURING ANY STORM. FOG WILL BE POSSIBLE WED MORNING AS SKIES CLEAR AND WINDS BECOME LIGHT. THERE WILL BE A CHANCE OF SHRAS/TSTMS FM WED THRU FRI AS A COLD FRNT APPROACHES FM THE W AND STALLS IN THE VICINITY. && .MARINE... NO HEADLINES XPCT AS HIGH PRS MOVES OFFSHORE RESULTING IN A RETURN SLY FLOW THRU THURSDAY. ONCE AGAIN...HIGH RES DATA SUGGESTS SOME CHANNELING UP THE BAY AT NIGHT...SO KEPT SPEEDS AOB 15 KTS FOR NOW. COLD FRONT APPRCHS THE AREA THURSDAY AFTN THEN CROSSES THE WTRS THURSDAY NIGHT BEFORE STALLING JUST OFF THE COAST FRIDAY. LACK OF CAA BEHIND THE FRONT WILL KEEP SUB-SCA CNDTNS INTO FRIDAY. LOCATION OF FRONT INTO THE WEEKEND WILL BE KEY TO THE FCST. RIGHT NOW THE BNDRY LOOKS TO STRADDLE THE COAST KEEPING WNDS IN A GNRL WEST DRCTN AT SPEEDS ARND 10 KTS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ/SAM NEAR TERM...AJZ/BMD/SAM SHORT TERM...AJZ/SAM LONG TERM...MPR AVIATION...MAS/DAP MARINE...MPR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
752 PM EDT TUE SEP 8 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 417 PM EDT TUE SEP 8 2015 WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A MID/UPPER LEVEL LOW SPINNING OVER MANITOBA. ONE SHORTWAVE IS LIFTING NE ACROSS NRN ONTARIO TO THE N OF LAKE OF THE WOODS. TAIL END OF THAT WAVE IS GENERATING SHRA/TSRA N OF THE MN/ONTARIO BORDER. CLOSER TO HOME... SHORTWAVE THAT LIFTED ACROSS WI TOWARD ERN UPPER MI BROUGHT WIDESPREAD SHRA/ISOLD TSTMS ACROSS ALL BUT FAR WRN UPPER MI TODAY. THAT ACTIVITY IS MOVING OUT QUICKLY NOW. TO THE W...IT APPEARS THAT THERE ARE 2 BOUNDARIES THAT STILL NEED TO BE WATCHED FOR NEW CONVECTIVE DEVELOPMENT. THE FIRST IS LAKE BREEZE BOUNDARY RUNNING FROM THE E SIDE OF THE KEWEENAW TO CNTRL GOGEBIC COUNTY...AND THE OTHER IS THE COLD FRONT MOVING ACROSS THE WRN PART OF LAKE SUPERIOR. MOSTLY FOLLOWED RECENT RADAR TRENDS TO MOVE LINGERING WIDESPREAD SHRA OUT OF THE ERN FCST AREA OVER THE NEXT FEW HRS. HELD LOW POPS BACK TO THE W AHEAD OF THE TWO AFOREMENTIONED BOUNDARIES. LATEST SPC MESOANALYSIS HAS MLCAPES UP TO AROUND 250J/KG OR SO AND SBCAPE TO AROUND 500J/KG AHEAD OF THE BOUNDARIES. WITH CU BUILDING UP PER VIS SATELLITE IMAGERY...CAN`T RULE OUT ISOLD/SCT SHRA DEVELOPMENT... PERHAPS A TSTM. WHATEVER HAPPENS...PCPN RISK WILL BE DONE BY LATE EVENING AS COLD FRONT SWEEPS ACROSS THE AREA. MUCH DRIER AIR MASS SURGING INTO THE AREA WILL FINALLY BRING AN END TO THE UNSEASONABLY LONG STRETCH OF HIGH DWPTS FOR THIS TIME OF YEAR. UPSTREAM IN NRN MN...SFC DWPTS HAVE FALLEN THRU THE 40S WITH EVEN SOME 30S SHOWING UP. EXPECT CLEARING SKIES FROM THE W TONIGHT. IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL AFFECT THE ERN SHORELINE AREAS BEFORE BEING SWEPT CLEAR BY THE MUCH DRIER AIR MASS. IT WILL BE THE COOLEST NIGHT IN WELL OVER A WEEK. MIN TEMPS SHOULD FALL INTO THE MID 40S OVER THE INTERIOR W HALF AND MOSTLY LOW/MID 50S ELSEWHERE. DRY AIR MASS WILL SET UP A NICE WED UNDER PLENTY OF SUNSHINE. DWPTS WILL BE LOW...MOSTLY IN THE 40S...WITH HIGH TEMPS IN THE UPPER 60S TO MID 70S...WARMEST IN THE AREAS THAT SEE DOWNSLOPING UNDER A WESTERLY WIND. SPEAKING OF WHICH...WINDS SHOULD BE GUSTY INTO THE 20 TO 30 MPH RANGE...ESPECIALLY OVER THE NW FCST AREA. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 414 PM EDT TUE SEP 8 2015 THE UPPER TROUGH THAT IS CURRENTLY MOVING EAST ACROSS SOUTH CENTRAL CANADA AND THE UPPER MISSISSIPPI VALLEY WILL MOVE INTO THE UPPER GREAT LAKES OVER THE NEXT 12 HOURS AND THEN AMPLIFY OVER THE REGION HEADING INTO THE END OF THE WORK WEEK AS A WAVE CURRENTLY MOVING INTO BRITISH COLUMBIA ROTATES THROUGH. THIS SETUP WILL LEAD TO GENERALLY BELOW NORMAL TEMPERATURES INTO THE START OF THE WEEKEND WITH PERIODS OF SHOWERS. AFTER A DRY START TO THE LONG TERM PERIOD ON WEDNESDAY EVENING (DUE TO AN EXISTING HIGH PRESSURE RIDGE)...A WEAK SURFACE TROUGH WILL MOVE EAST ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE GREAT LAKES REGION LATER WEDNESDAY NIGHT AND THURSDAY. THIS WILL BE IN RESPONSE TO THE SHORTWAVE CURRENTLY MOVING INTO BRITISH COLUMBIA THAT WILL BE ROUNDING THE BASE OF THE UPPER TROUGH. SHOWERS ARE EXPECTED TO DEVELOP IN SOUTHERN MINNESOTA AND WESTERN WISCONSIN ON WEDNESDAY NIGHT AND THEN SPREADING EAST-NORTHEAST INTO PORTIONS OF UPPER MICHIGAN. MODELS ARE DIFFERING ON THE NORTHWEST EXTENT OF THE SHOWERS...LARGELY DUE TO THE TRACK OF THE SHORTWAVE WITH HALF TRACKING IT ACROSS NORTHERN WISCONSIN (PUSHING PRECIP FARTHER NORTH) AND THE OTHER HALF TRACK IT MORE ACROSS SOUTHERN WISCONSIN (AND HAS PRECIP ONLY BRUSHING THE SOUTHERN THIRD OF THE AREA) ON THURSDAY. DID SEE A SOUTHEAST TREND WITH THE 12Z ECMWF...WHICH IS MORE IN LINE WITH THE 12Z GFS/GEM...SO WHILE CONFIDENCE IS LOW...FELT IT WAS REASONABLE TO TREND THE CHANCE POPS FARTHER TO THE SOUTHEAST AND MORE OVER THE SOUTH CENTRAL AND ALONG THE LAKE MICHIGAN SHORELINE. THOSE SHOWERS WILL DEPART ON THURSDAY NIGHT AS THE SHORTWAVE AND SURFACE TROUGH DEPARTS. THIS WILL ALLOW MUCH COLDER AIR TO SURGE SOUTH ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY...WITH 850MB TEMPS FALLING TO 1-2C. SINCE LAKE SUPERIOR TEMPERATURES ARE IN THE 12-18C RANGE...EXPECT SOME POTENTIAL OF LAKE EFFECT/ENHANCED RAIN FOR THURSDAY NIGHT INTO FRIDAY. MODELS SHOWING DECENT MOISTURE BELOW THE INVERSION AROUND 750MB...SO HAVE CHANCE POPS FOR THE FAVORED NORTHERLY WIND LOCATIONS NEAR LAKE SUPERIOR DURING THAT TIME. WILL LIKELY NEED TO TREND POPS UP FURTHER IF THE LATEST MODEL TRENDS CONTINUE. IN ADDITION...THAT COLD AIR AND DECENT CLOUD COVER FOR MUCH OF THE DAY ON FRIDAY WILL KEEP HIGHS IN THE 50S. A SURFACE HIGH OFF TO THE WEST IN THE DAKOTAS WILL TRY TO PUSH A SURFACE RIDGE INTO THE AREA ON FRIDAY...BUT IT WILL LIKELY REALLY ARRIVE ON SATURDAY AS THE UPPER TROUGH BEGINS TO SHIFT EAST. DRIER AIR ASSOCIATED WITH THE HIGH WILL LEAD TO DECREASING CLOUDS FROM WEST TO EAST ON FRIDAY AFTERNOON...WITH CLEAR SKIES REMAINING IN PLACE THROUGH MUCH OF THE WEEKEND. SATURDAY WILL REMAIN BELOW NORMAL FOR HIGHS...BUT WITH THE UPPER RIDGE AXIS SHIFTING EAST FROM THE DAKOTAS AND INTO THE UPPER GREAT LAKES REGION FOR SUNDAY AND MONDAY...EXPECT HIGHS TO RISE BACK UP TO NORMAL OR EVEN SLIGHTLY ABOVE NORMAL VALUES. WILL NEED TO WATCH THE EVOLUTION OF THE UPPER TROUGH JUST TO THE EAST-SOUTHEAST OF THE AREA FOR SUNDAY/MONDAY TIME FRAME...AS THERE ARE SOME HINTS OF IT ROTATING BACK NORTHWEST AS THE UPPER RIDGE REMAINS FARTHER WEST. THAT WOULD LEAD TO COOLER AND BETTER OPPORTUNITIES FOR RAIN. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 750 PM EDT TUE SEP 8 2015 COLD FRONT HAS WORKED THROUGH KIWD AND KCMX. EXPECT VFR CONDITIONS THROUGH WEDNESDAY. WEST WINDS WILL BECOME GUSTY FOR A TIME THIS EVENING AT KCMX...THEN AGAIN ON WEDNESDAY AT KIWD AND KCMX. COLD FRONT STILL WEST OF KSAW...SO THERE MAY STILL BE ISOLD SHRA THERE IN THE NEXT COUPLE HOURS. EXPECT VFR CONDITIONS TO PREVAIL THOUGH INTO WEDNESDAY WITH GUSTY WEST WINDS DEVELOPING AS WELL. WINDS ARE EXPECTED TO GUST TO 18-26 KTS ON WEDNESDAY AT ALL THE TERMINALS...STRONGEST AT THE MORE EXPOSED KCMX LOCATION. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 417 PM EDT TUE SEP 8 2015 FIRST UP...IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL BE SWEPT OFF THE ERN PORTION OF THE LAKE TONIGHT AS STRENGTHENING W WINDS BEHIND A PASSING COLD FRONT USHER IN A MUCH DRIER AIR MASS TONIGHT. INCOMING PRES RISES WILL HELP BOOST W WIND GUSTS TO 25-30KT FOR A TIME AFTER FRONTAL PASSAGE. DURING WED...W WINDS OF 15-25KT WILL GENERALLY BE THE RULE...BUT OVER CNTRL LAKE SUPERIOR AND IN PARTICULAR AROUND THE TIP OF THE KEWEENAW PENINSULA...WINDS OF 20- 30KT ARE EXPECTED. LIGHTER WINDS OF 10-20KT ARE EXPECTED FOR WED NIGHT/THU. ARRIVAL OF A COLDER AIR MASS AHEAD OF APPROACHING SFC HIGH PRES WILL LEAD TO A PERIOD OF STRONGER WINDS OF 15-30KT AGAIN THU NIGHT INTO AT LEAST FRI MORNING...STRONGEST OVER THE E HALF. WINDS WILL SLOWLY DIMINISH W TO E FRI AFTN THRU SAT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...JLA MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
102 PM EDT MON SEP 7 2015 .AVIATION... COLD FRONT SLOWLY SLIDING INTO SOUTHEAST MICHIGAN THIS AFTERNOON EXPECTED TO TOUCH OFF SCATTERED SHOWER/THUNDERSTORM ACTIVITY...BUT PREFERENCE IS TO INCLUDE JUST TEMPO GROUP FOR SHOWERS ACROSS NORTHERN TAF SITES...UNTIL BETTER HANDLE ON THUNDERSTORM COVERAGE IS REALIZED. FRONTAL BOUNDARY WILL BE STALLED/NEARLY STATIONARY OVER THE AREA TONIGHT...AND UPTICK IN SHOWER/THUNDERSTORM ACTIVITY IS EXPECTED AS LOW LEVEL CONVERGENCE/JET INCREASES A BIT. HOWEVER...EXACT POSITION OF THIS EXPANDING COVERAGE OF ACTIVITY IS UNCERTAIN...BUT EXPECTATIONS ARE FOR MIGRATORY NORTHWARD JOG THROUGH THE NIGHT. OUTSIDE OF THIS ACTIVITY...VFR CEILINGS ARE EXPECTED WITH LIGHT WINDS (SAVE FOR THIS AFTERNOONS SOUTHWEST WINDS ABOVE 10 KNOTS). FOG WILL LIKELY BECOME AN ISSUE TONIGHT...ESPECIALLY IF CONVECTIVE ACTIVITY/MID CLOUDS DO NOT PAN OUT...BUT HAVE GONE MOSTLY CONSERVATIVE (MVFR) FOR NOW. FOR DTW...THERE REMAINS A LOW CHANCE OF SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON INTO EARLY THIS EVENING...BUT HAVE ELECTED TO INCLUDE THE BETTER CHANCE IN THE TAF TOWARD MIDNIGHT. FOR DTW... //DTW THRESHOLD PROBABILITIES... * LOW CONFIDENCE IN THUNDERSTORMS LATE TODAY THROUGH TOMORROW. * LOW CONFIDENCE IN CEILINGS AOB 5000 FEET. && .PREV DISCUSSION...ISSUED 1051 AM EDT MON SEP 7 2015 UPDATE... THE PROSPECTS FOR SHOWERS/THUNDERSTORMS STILL LOOKS TO BE FAIRLY LOW/SCATTERED COVERAGE EXPECTED TODAY...AS UPPER LEVEL RIDGE (589 DAM AT 500 MB )IN PLACE IS SLOW TO FLATTEN. SURFACE COLD FRONT/FOLDING OVER MOISTURE PLUME (PW OF 2 INCHES)/850-700 MB THETA- E RIDGE AXIS WILL PROVIDE FOCUS FOR ACTIVITY...BUT THE FRONT IS DISPLACED EAST OF THE UPPER LEVEL FORCING...AS 500 MB TEMPS ACTUALLY LOOK TO RISE TOWARD -6 C TOWARD 00Z TUESDAY. MID LEVEL LAPSE RATES (700-500 MB) WILL BE WEAK TODAY...BUT ENOUGH MLCAPE (1000-1500 J/KG) BUILDING TO MAINTAIN THUNDERSTORM THREAT...BUT 0-6 KM BULK SHEAR GENERALLY AROUND 20 KNOTS...DOES NOT DRAW A HUGE CONCERN FOR SEVERE WEATHER...BUT VERY HEAVY RAINFALL IS CERTAINTY EXPECTED WITH ANY STORM. DEEP LAYER UNIDIRECTIONAL WEST-SOUTHWEST WINDS SHOULD KEEP CELLS MOVING JUST ENOUGH. 12Z NAM AND LATEST RUC BEING A BIT MORE GENEROUS WITH COVERAGE OVER NORTH HALF OF THE CWA THIS AFTERNOON...WITH LITTLE OR NO CAP IN THIS MOIST ENVIRONMENT. HOWEVER...FORECASTED SURFACE DEW PTS LOOK TO BE A TOUCH TOO HIGH...BUT STILL MAY DECIDE TO NUDGE POPS UP A JUST A BIT...DEPENDING ON TREND AND FURTHER ANALYSIS. TEMPERATURES REMAIN ON TRACK TO REACH INTO THE MID/UPPER 80S...WITH 90 DEGREES LIKELY ACROSS EASTERN AREAS...INCLUDING CITY OF DETROIT. HIGH BASED CLOUDS SHOULD PROVIDE MODEST RELIEF...BUT CERTAINLY HOT WITH DEW PTS IN 65 TO 70 DEGREE RANGE. INDICATIVE OF THIS HOT AND MOIST AIRMASS...FLINT AND SAGINAW COULD SET RECORD HIGH MINIMUM VALUES FOR TODAY (SEPTEMBER 7). SAGINAW LOW THIS MORNING WAS 73 DEGREES...WITH THE RECORD BEING 71 DEGREES SET IN 1985. MEANWHILE...FLINT BOTTOMED OUT AT 71 DEGREES...WHICH WOULD TIE THE RECORD HIGH MINIMUM FOR THE DATE...PREVIOUSLY SET IN 2007. HOWEVER...STILL HAVE POTENTIAL FOR TEMPERATURES TO DROP TOWARD 70 DEGREES BY MIDNIGHT TONIGHT...ESPECIALLY WITH ANY HELP FROM RAIN COOLED SHOWERS. PREV DISCUSSION...ISSUED 323 AM EDT MON SEP 7 2015 SHORT TERM...TODAY AND TONIGHT CONVECTION REMAINS FIRMLY ANCHORED TO ENHANCED SOUTHWESTERLY FLOW ATTENDANT TO THE LEAD EDGE OF HEIGHT FALLS OVER THE WESTERN AND NORTHERN GREAT LAKES EARLY THIS MORNING. NWP ADAMANTLY KILL THIS ACTIVITY DURING THE EARLY MORNING, BUT THETA-E TRANSPORT HAS PROVEN IMPRESSIVE AND CONVECTION OVER NORTHERN IL/SOUTHERN WI HAS SO FAR BEEN RESILIENT. THE CORE OF THE LLJ AXIS WITHIN WHICH THIS ACTIVITY IS EMBEDDED WILL GRADUALLY WEAKEN THROUGH MORNING WHICH DOES SUPPORT EVENTUAL UPSTREAM DISSIPATION BEFORE THE LLJ FINALLY IMPINGES ON THE FAR WESTERN CWA AFTER ABOUT 20Z. HOWEVER, DIURNAL HEATING - TEMPERED BY CONVECTIVE DEBRIS - AND SOME DEGREE OF ONGOING MOISTURE TRANSPORT WITHIN WEAKER SWLY FLOW OUGHT TO BE SUFFICIENT TO REGENERATE SHOWERS ALONG THE EASTERN FRINGE OF WHAT REMAINS OF THE ENHANCED SOUTHWESTERLIES AFTER 18Z. INDEED, PROGGED NAM12 SOUNDINGS DEPICT AN IMPRESSIVE MOISTENING ABOVE THE LFC WHICH SHOULD HELP GET THINGS GOING, CONDITIONAL ON SUFFICIENT BOUNDARY LAYER DEEPENING. RECENT HRRR CYCLES SUPPORT THE IDEA OF REGENERATION AS WELL. LACK OF INSTABILITY AND SHEAR WILL LIMIT TSTORM POTENTIAL IN GENERAL, BUT PWATS NEAR 2 INCHES ARE A NOD TO THE PRIMARY THREAT OF HEAVY RAIN WITH ANYTHING THAT DEVELOPS. THOUGH SENSITIVE TO CONVECTIVE COVERAGE, HIGHS SHOULD EASILY REACH 90 ACROSS THE FAR EAST, WHILE THICKER CLOUD COVER EARLIER IN THE DAY IS FORECAST TO LIMIT THE SAGINAW VALLEY TO THE MID 80S. RAPID INTENSIFYING OF THE UPPER JET OVER LAKE SUPERIOR WILL ENSUE BY SEVERAL HOURS AFTER SUNSET MARKING THE ARRIVAL OF MORE VIGOROUS UPPER ENERGY EMBEDDED WITHIN BROAD CYCLONIC FLOW AROUND THE MANITOBA CYCLONE. LOWER TROPOSPHERIC FRONTAL ZONE WILL UNDERGO SUBSEQUENT SHARPENING WHILE A SECONDARY THETA-E SURGE ORGANIZES WITHIN THE RENEWED LLJ EMERGING OUT OF THE MIDDLE MS VALLEY. THE PRIMARY UNCERTAINTY DURING THIS TIME IS WHETHER THIS PROCESS WILL ULTIMATELY SUSTAIN EXISTING/LEFT OVER DIURNAL ACTIVITY OR IF DAYTIME ACTIVITY WILL WANE COMPLETELY AND GIVE WAY TO SEVERAL HOURS OF DOWN-TIME BEFORE ISENTROPIC ASCENT RAMPS UP AFTER MIDNIGHT. THIS WILL LIKELY MAKE ALL THE DIFFERENCE FOR THE DETROIT METRO AREA, AS DISSIPATION OF DIURNAL ACTIVITY WOULD LIKELY SPELL THE END OF RAIN POTENTIAL FOR THE EVENING AS FORCING ULTIMATELY REORGANIZES ORGANIZES FURTHER NORTH ALONG THE M59/I-69 CORRIDOR. CONFIDENCE BY EARLY TUESDAY MORNING IS HIGHEST IN THE SAGINAW VALLEY WITHIN THE CORRIDOR OF STRONGEST ASCENT AND DECREASES TOWARD THE THUMB. POPS ARE THEREFORE TAPERED FROM CATEGORICAL FOR THE FORMER TO ENTRY LEVEL LIKELY FOR THE LATTER. SKINNY CAPE PROFILE, 2+" PWATS, AND DEVELOPING 12KFT WARM CLOUD LAYER WILL CERTAINLY SUPPORT AN ENVIRONMENT CAPABLE OF PROLIFIC HYDROMETEOR PRODUCTION AND RESULTANT HEAVY DOWNPOURS. ACCORDINGLY, QPF HAS BEEN RAMPED UP TO BASIN AVERAGES OF ABOUT A HALF INCH AFTER MIDNIGHT. DEPENDING ON COVERAGE, THE POTENTIAL FOR FURTHER UPWARD ADJUSTMENT WILL EXIST. LOWS WILL HOVER NEAR 70 FOR YET ANOTHER NIGHT AS HIGH DEWPOINTS PUT AN A FLOOR ON LOW TEMP POTENTIAL. SOME RELIEF ACROSS THE NORTH WILL COME IN THE FORM OF RAINFALL, BUT SOUTHERN AREAS WILL REMAIN LARGELY PRECIP FREE AFTER SUNSET AND WILL BE WARM AND MUGGY ONCE AGAIN. LONG TERM... THE LONG TERM WILL FIRST DEAL WITH A LONG DURATION RAINFALL ALONG A STALLED FRONT...FOLLOWED BY THE INFILTRATION OF A MUCH COOLER AIRMASS FOR THE WEEKEND. UPPER LEVEL LOW OVER SOUTHERN CANADA WILL APPROACH WESTERN ONTARIO TUESDAY MORNING. SEVERAL WEAK SHORTWAVES TRACKING THROUGH THE LONGWAVE TROUGH AND HEIGHT FALLS ASSOCIATED WITH THE LOW WILL CONTINUE TO BREAK DOWN THE RIDGE OVER THE EASTERN CONUS. THE FRONT WILL BE DRAPED ACROSS MID MI BY TUESDAY MORNING WITH THE PRECIPITATION EVENT WELL ON ITS WAY. A SHORTWAVE IS PROGGED TO LIFT ALONG THE FRONT EARLY TUESDAY WHICH WILL DEVELOP A SFC LOW NEAR IOWA. THIS WILL LIFT THE FRONT BACK NORTHWARD TEMPORARILY AS A WARM FRONT...KEEPING THE HIGHEST POPS ACROSS THE SAGINAW VALLEY. THIS SFC LOW WILL LIFT NE THROUGH MID MI TUESDAY EVENING WHICH WILL SIGNAL THE START OF A MORE PROGRESSIVE SYSTEM OVERALL OWNING TO A STRONG UPPER JET MAX COMING ASHORE BRITISH COLUMBIA MONDAY NIGHT AND SURGING AROUND THE UPPER LOW. THIS WILL FORCE THE COLD FRONT ACROSS LOWER MI LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. THIS SYSTEM OVERALL WILL BE A VERY EFFICIENT RAIN MAKER AS PWATS LOOK TO HOVER JUST SHY OF 2 INCHES THROUGH THE DURATION OF THE EVENT. STEADY AND STRONG 850MB LL JET WILL CONTINUALLY FEED MOISTURE NORTHWARD AHEAD OF THE FRONT. IMPRESSIVE LL THETA E FIELD AS WELL WITH AN ENHANCED RIBBON OF WARM/MOIST AIR JUST SITTING OVER THE STATE. INSTABILITY WILL NOT BE TOO GREAT BUT A TALL SKINNY CAPE PROFILE WOULD FAVOR HEAVY RAINFALL. POPS WILL BE DEPENDENT ON SHORTWAVE ACTIVITY...PULSES IN THE LL JET...AND FLUCTUATIONS IN THE FRONTAL BOUNDARY SO GENERALLY SPEAKING...LIKELYS WILL BE FEATURES ACROSS THE NORTH WITH CHANCE POPS FURTHER SOUTH WITH FUTURE UPDATES PEGGING THE SMALLER SCALE FORCINGS. SHOWERS WILL DOMINATE BUT SOME ISOLATED/EMBEDDED THUNDERSTORMS CANNOT BE RULED OUT. BEST CHANCES FOR THUNDERSTORMS WILL BE WITH THE ACTUAL FROPA WEDNESDAY MORNING. TEMPERATURES WILL BE TRICKY TUESDAY AS THE FRONTAL LOCATION AND EXCESSIVE CLOUDS ACROSS THE NORTH WILL LIKELY LEAD TO A HEALTHY GRADIENT ACROSS SE MI. SHOULD STILL BE ABLE TO GET INTO THE MID/UPPER 80S ACROSS THE SOUTH AND DETROIT METRO WITH ONGOING SHOWERS AND CLOUDS KEEPING LOCATIONS FURTHER NORTH CLOSER TO 80 OR EVEN IN THE UPPER 70S. PASSAGE OF THE COLD FRONT WILL BRING ABOUT SOME NOTABLE CHANGES FOR THE REMAINDER OF THE LONG TERM. MUCH COOLER AND DRIER AIR WILL FEED INTO THE AREA WITH NORTHERLY FLOW. A WAVE DIVING INTO THE BASE OF THE LONGWAVE TROUGH WILL THEN DEEPEN AND CUTOFF AS IT REACHES THE GREAT LAKES FOR THE WEEKEND. 850MB TEMPS ARE FORECAST TO FALL BACK INTO THE SINGLE DIGITS WITH HIGH TEMPERATURES IN THE LOW 70S...AND POSSIBLY THE UPPER 60S FRIDAY AND SATURDAY. SHOWERS WILL BE POSSIBLE STARTING FRIDAY NIGHT ASSOCIATED WITH THE BROAD LIFT FROM THE UPPER LEVEL LOW AND ANY SFC PRESSURE FALLS WITH IT. MARINE... SOUTHWESTERLY WINDS WILL BECOME TODAY AHEAD OF AN APPROACHING FRONT. THIS SLOW MOVING FRONT WILL BRING A CHANCE OF SHOWERS THIS MORNING FOR NORTHERN LAKE HURON AND LATER THIS AFTERNOON FURTHER SOUTH. A THUNDERSTORM CANNOT BE RULES OUT BUT NOT EXPECTING ANYTHING STRONG OR WIDESPREAD. A SURFACE LOW WILL THEN TRACK THROUGH THE AREA LATE TUESDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS THROUGH EARLY WEDNESDAY. A PERIOD OF GUSTY SOUTHWEST WINDS WILL BE POSSIBLE ON TUESDAY AS THIS LOW PASSES THROUGH NORTHERN LOWER MICHIGAN. THIS WILL BE ESPECIALLY TRUE OVER SAGINAW BAY DUE TO FUNNELING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....SF UPDATE.......SF SHORT TERM...JVC LONG TERM....DRK MARINE.......DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1142 AM EDT MON SEP 7 2015 LATEST UPDATE... HYDRO .SYNOPSIS... ISSUED AT 318 AM EDT MON SEP 7 2015 THE HOLIDAY WEEKEND WILL COME TO A RATHER WET CLOSE AS A SLOW MOVING FRONTAL SYSTEM STALLS OVER THE AREA TONIGHT INTO TUESDAY BEFORE FINALLY CLEARING THE AREA BY MID MORNING WEDNESDAY. MOST OF THE AREA WILL HAVE A WARM START TO THE DAY DAY WITH SOME SUNSHINE BUT SHOWERS AND THUNDERSTORMS WILL OVERSPREAD THE AREA FROM NORTHWEST TO SOUTHEAST BY LATE AFTERNOON. ALL AREAS WILL SEE PERIODS OF SHOWERS AND THUNDERSTORMS TONIGHT INTO WEDNESDAY MORNING. RAINFALL WILL BE HEAVY AT TIMES. COOLER AND DRY WEATHER FOLLOWS LATER WEDNESDAY INTO THURSDAY. YET ANOTHER STORM COULD MEAN A WET WEEKEND BUT THAT WILL DEPEND ON THE STORMS TRACK. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 318 AM EDT MON SEP 7 2015 MUCH HAS BEEN WRITTEN ABOUT THE RAINFALL POTENTIAL FOR TONIGHT INTO WEDNESDAY MORNING IN ALL OF OUR DISCUSSIONS FOR AT LEAST 4 DAYS NOW AND LITTLE HAS CHANGED. EXPECT A HEAVY RAINFALL EVENT OVER MOST OF THE AREA TONIGHT INTO WEDNESDAY MORNING. THE EXACT AXIS OF THE HEAVIEST RAINFALL IS UNCERTAIN AT THIS TIME BUT IT WOULD SEEM THE BEST GUESS IS CURRENTLY NORTH OF A LINE FROM SOUTH HAVEN TO ALMA. I WOULD EXPECT SOME LOCALIZED RAINFALL AMOUNTS COULD EXCEEDED 5 INCHES FROM THIS EVENT SO LOCALIZED FLOODING WOULD BE AN ISSUE. THE PRECIPITABLE WATER VALUES RISE TO NEAR 2 INCHES BY LATE AFTERNOON OVER OUR CENTRAL CWA AND REMAIN IN PLACE UNTIL THE COLD FRONT FINALLY CLEARS THE AREA WHEN THE SECOND UPPER WAVE MOVES THROUGH THE AREA WEDNESDAY MORNING. THIS IS A 1 DAY IN 5 TO 10 YEAR SORT OF EVENT FOR SOUTHWEST LOWER MICHIGAN. CLEARLY SOMETHING WE WILL NEED TO MONITOR. THE CONVECTION OVER WISCONSIN AND LAKE MICHIGAN WILL WEAKEN SOME AS IT MOVES INTO OUR CWA THIS MORNING BUT WILL RE-FIRE THIS AFTERNOON AS THE DEEP MOISTURE MOVES OVERHEAD. THE FIRST PRIMARY UPPER WAVE WILL START THE MAIN EVENT LATER TONIGHT AND THAT WILL LAST INTO TUESDAY MORNING. THE SECOND UPPER WAVE WILL ENHANCE ACTIVITY TUESDAY EVENING INTO WEDNESDAY MORNING. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 318 AM EDT MON SEP 7 2015 A COLD FRONT SHOULD BE JUST SOUTH OF THE CWA WEDNESDAY NIGHT AND COOLER AIR WILL BE MOVING INTO LOWER MICHIGAN COURTESY OF A DEEP UPPER TROUGH THAT DEVELOPS BY THE END OF THE WEEK. HIGHS IN THE 60S ARE EXPECTED FRIDAY AND SATURDAY. THE UPPER TROUGH WILL ALSO RESULT IN SOME SHOWERS THURSDAY NIGHT AND FRIDAY. THE ECMWF IS QUITE A BIT DEEPER THAN THE GFS AND CLOSES OFF THE TROUGH INTO A UPPER LOW WHEREAS THE GFS KEEPS THE SYSTEM AS AN OPEN WAVE. THE GFS SOLUTION WOULD LIKELY RESULT IN DRIER AND WARMER CONDITONS...BUT STILL MUCH COOLER THAN WHAT WE HAVE SEEN RECENTLY. MODEL DIFFERENCES REALLY AFFECT THE END OF THE FORECAST. THE OPEN WAVE ON THE GFS QUICKLY MOVES EAST ALLOWING TEMPS TO WARM UP BY THE END OF THE WEEKEND TO AROUND 12C...WHILE THE ECMWF WOULD HOLD ONTO H8 TEMPS NEAR 7C. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 737 AM EDT MON SEP 7 2015 CURRENTLY ALL TAF SITES ARE VFR AND FOR THE MOST PART THEY SHOULD STAY THAT WAY THROUGH 08/06Z OR SO. THE MAIN AREA OF CONVECTION... MOSTLY JUST SHOWER NOT THUNDERSTORMS...SHOULD MOVE INTO THE TAF MKG AND GRR TAF SITES IN THE 06Z TO 09Z TIME FRAME. THE SHOWERS MORE THAN LIKELY WILL NOT REACH THE OTHER TAF SITES BY 08/12Z. IN THE VERY SHORT TERM...THE SHOWERS/THUNDERSTORMS CLOSE TO THE MKG TAF SITE SEE WANT TO DISSIPATE BEFORE REACHING MKG. THAT ALSO AGREES WITH OUR HIGH RESOLUTION MODELS LIKE THE RAP OR HRRR. && .MARINE... ISSUED AT 345 AM EDT MON SEP 7 2015 THE BEACH HAZARD AND SMALL CRAFT ADVISORIES HAVE BEEN DISCONTINUED. WE MAY NEED TO REISSUE THESE PRODUCTS WEDNESDAY WHEN THE COLD AIR COMES BACK INTO THE AREA. && .HYDROLOGY... ISSUED AT 1142 AM EDT MON SEP 7 2015 WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS THE FORECAST AREA. A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT. WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING AND WEDNESDAY MORNING. THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...WDM SHORT TERM...WDM LONG TERM...99 AVIATION...WDM HYDROLOGY...JAM MARINE...WDM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1051 AM EDT MON SEP 7 2015 .UPDATE... THE PROSPECTS FOR SHOWERS/THUNDERSTORMS STILL LOOKS TO BE FAIRLY LOW/SCATTERED COVERAGE EXPECTED TODAY...AS UPPER LEVEL RIDGE (589 DAM AT 500 MB )IN PLACE IS SLOW TO FLATTEN. SURFACE COLD FRONT/FOLDING OVER MOISTURE PLUME (PW OF 2 INCHES)/850-700 MB THETA- E RIDGE AXIS WILL PROVIDE FOCUS FOR ACTIVITY...BUT THE FRONT IS DISPLACED EAST OF THE UPPER LEVEL FORCING...AS 500 MB TEMPS ACTUALLY LOOK TO RISE TOWARD -6 C TOWARD 00Z TUESDAY. MID LEVEL LAPSE RATES (700-500 MB) WILL BE WEAK TODAY...BUT ENOUGH MLCAPE (1000-1500 J/KG) BUILDING TO MAINTAIN THUNDERSTORM THREAT...BUT 0-6 KM BULK SHEAR GENERALLY AROUND 20 KNOTS...DOES NOT DRAW A HUGE CONCERN FOR SEVERE WEATHER...BUT VERY HEAVY RAINFALL IS CERTAINTY EXPECTED WITH ANY STORM. DEEP LAYER UNIDIRECTIONAL WEST-SOUTHWEST WINDS SHOULD KEEP CELLS MOVING JUST ENOUGH. 12Z NAM AND LATEST RUC BEING A BIT MORE GENEROUS WITH COVERAGE OVER NORTH HALF OF THE CWA THIS AFTERNOON...WITH LITTLE OR NO CAP IN THIS MOIST ENVIRONMENT. HOWEVER...FORECASTED SURFACE DEW PTS LOOK TO BE A TOUCH TOO HIGH...BUT STILL MAY DECIDE TO NUDGE POPS UP A JUST A BIT...DEPENDING ON TREND AND FURTHER ANALYSIS. TEMPERATURES REMAIN ON TRACK TO REACH INTO THE MID/UPPER 80S...WITH 90 DEGREES LIKELY ACROSS EASTERN AREAS...INCLUDING CITY OF DETROIT. HIGH BASED CLOUDS SHOULD PROVIDE MODEST RELIEF...BUT CERTAINLY HOT WITH DEW PTS IN 65 TO 70 DEGREE RANGE. INDICATIVE OF THIS HOT AND MOIST AIRMASS...FLINT AND SAGINAW COULD SET RECORD HIGH MINIMUM VALUES FOR TODAY (SEPTEMBER 7). SAGINAW LOW THIS MORNING WAS 73 DEGREES...WITH THE RECORD BEING 71 DEGREES SET IN 1985. MEANWHILE...FLINT BOTTOMED OUT AT 71 DEGREES...WHICH WOULD TIE THE RECORD HIGH MINIMUM FOR THE DATE...PREVIOUSLY SET IN 2007. HOWEVER...STILL HAVE POTENTIAL FOR TEMPERATURES TO DROP TOWARD 70 DEGREES BY MIDNIGHT TONIGHT...ESPECIALLY WITH ANY HELP FROM RAIN COOLED SHOWERS. && .AVIATION...ISSUED 637 AM EDT MON SEP 7 2015 WIDESPREAD VFR WILL PERSIST UNTIL AT LEAST LATE TONIGHT AS THE LOWER ATMOSPHERE REMAINS DRY. LONE EXCEPTION MAY BE MBS LATE THIS MORNING AS SOME DEGREE OF CONVECTIVE REMNANTS ROLL THROUGH BRINGING A HEAVY SHOWER OR TWO TO THE AIRFIELD. THIS ACTIVITY MAY REIGNITE WITH DIURNAL HEATING /PERHAPS ALONG REMNANT OUTFLOW/ WARRANTING JUST A TEMPO FOR HIGHER BASED SHOWERS ATTM. FORCING WILL ORGANIZE NORTH OF THE DETROIT AREA BRINGING SHOWERS FROM KPTK NORTH BY EARLY TUESDAY MORNING...BUT BRUNT OF ACTIVITY WILL BE FOCUSED FROM KMBS NORTH. FOR DTW...CLOUDS MAY BE BRIEFLY SCATTERED AOB 5KFT BEFORE LIFTING. //DTW THRESHOLD PROBABILITIES... * NONE && .PREV DISCUSSION...ISSUED 323 AM EDT MON SEP 7 2015 SHORT TERM...TODAY AND TONIGHT CONVECTION REMAINS FIRMLY ANCHORED TO ENHANCED SOUTHWESTERLY FLOW ATTENDANT TO THE LEAD EDGE OF HEIGHT FALLS OVER THE WESTERN AND NORTHERN GREAT LAKES EARLY THIS MORNING. NWP ADAMANTLY KILL THIS ACTIVITY DURING THE EARLY MORNING, BUT THETA-E TRANSPORT HAS PROVEN IMPRESSIVE AND CONVECTION OVER NORTHERN IL/SOUTHERN WI HAS SO FAR BEEN RESILIENT. THE CORE OF THE LLJ AXIS WITHIN WHICH THIS ACTIVITY IS EMBEDDED WILL GRADUALLY WEAKEN THROUGH MORNING WHICH DOES SUPPORT EVENTUAL UPSTREAM DISSIPATION BEFORE THE LLJ FINALLY IMPINGES ON THE FAR WESTERN CWA AFTER ABOUT 20Z. HOWEVER, DIURNAL HEATING - TEMPERED BY CONVECTIVE DEBRIS - AND SOME DEGREE OF ONGOING MOISTURE TRANSPORT WITHIN WEAKER SWLY FLOW OUGHT TO BE SUFFICIENT TO REGENERATE SHOWERS ALONG THE EASTERN FRINGE OF WHAT REMAINS OF THE ENHANCED SOUTHWESTERLIES AFTER 18Z. INDEED, PROGGED NAM12 SOUNDINGS DEPICT AN IMPRESSIVE MOISTENING ABOVE THE LFC WHICH SHOULD HELP GET THINGS GOING, CONDITIONAL ON SUFFICIENT BOUNDARY LAYER DEEPENING. RECENT HRRR CYCLES SUPPORT THE IDEA OF REGENERATION AS WELL. LACK OF INSTABILITY AND SHEAR WILL LIMIT TSTORM POTENTIAL IN GENERAL, BUT PWATS NEAR 2 INCHES ARE A NOD TO THE PRIMARY THREAT OF HEAVY RAIN WITH ANYTHING THAT DEVELOPS. THOUGH SENSITIVE TO CONVECTIVE COVERAGE, HIGHS SHOULD EASILY REACH 90 ACROSS THE FAR EAST, WHILE THICKER CLOUD COVER EARLIER IN THE DAY IS FORECAST TO LIMIT THE SAGINAW VALLEY TO THE MID 80S. RAPID INTENSIFYING OF THE UPPER JET OVER LAKE SUPERIOR WILL ENSUE BY SEVERAL HOURS AFTER SUNSET MARKING THE ARRIVAL OF MORE VIGOROUS UPPER ENERGY EMBEDDED WITHIN BROAD CYCLONIC FLOW AROUND THE MANITOBA CYCLONE. LOWER TROPOSPHERIC FRONTAL ZONE WILL UNDERGO SUBSEQUENT SHARPENING WHILE A SECONDARY THETA-E SURGE ORGANIZES WITHIN THE RENEWED LLJ EMERGING OUT OF THE MIDDLE MS VALLEY. THE PRIMARY UNCERTAINTY DURING THIS TIME IS WHETHER THIS PROCESS WILL ULTIMATELY SUSTAIN EXISTING/LEFT OVER DIURNAL ACTIVITY OR IF DAYTIME ACTIVITY WILL WANE COMPLETELY AND GIVE WAY TO SEVERAL HOURS OF DOWN-TIME BEFORE ISENTROPIC ASCENT RAMPS UP AFTER MIDNIGHT. THIS WILL LIKELY MAKE ALL THE DIFFERENCE FOR THE DETROIT METRO AREA, AS DISSIPATION OF DIURNAL ACTIVITY WOULD LIKELY SPELL THE END OF RAIN POTENTIAL FOR THE EVENING AS FORCING ULTIMATELY REORGANIZES ORGANIZES FURTHER NORTH ALONG THE M59/I-69 CORRIDOR. CONFIDENCE BY EARLY TUESDAY MORNING IS HIGHEST IN THE SAGINAW VALLEY WITHIN THE CORRIDOR OF STRONGEST ASCENT AND DECREASES TOWARD THE THUMB. POPS ARE THEREFORE TAPERED FROM CATEGORICAL FOR THE FORMER TO ENTRY LEVEL LIKELY FOR THE LATTER. SKINNY CAPE PROFILE, 2+" PWATS, AND DEVELOPING 12KFT WARM CLOUD LAYER WILL CERTAINLY SUPPORT AN ENVIRONMENT CAPABLE OF PROLIFIC HYDROMETEOR PRODUCTION AND RESULTANT HEAVY DOWNPOURS. ACCORDINGLY, QPF HAS BEEN RAMPED UP TO BASIN AVERAGES OF ABOUT A HALF INCH AFTER MIDNIGHT. DEPENDING ON COVERAGE, THE POTENTIAL FOR FURTHER UPWARD ADJUSTMENT WILL EXIST. LOWS WILL HOVER NEAR 70 FOR YET ANOTHER NIGHT AS HIGH DEWPOINTS PUT AN A FLOOR ON LOW TEMP POTENTIAL. SOME RELIEF ACROSS THE NORTH WILL COME IN THE FORM OF RAINFALL, BUT SOUTHERN AREAS WILL REMAIN LARGELY PRECIP FREE AFTER SUNSET AND WILL BE WARM AND MUGGY ONCE AGAIN. LONG TERM... THE LONG TERM WILL FIRST DEAL WITH A LONG DURATION RAINFALL ALONG A STALLED FRONT...FOLLOWED BY THE INFILTRATION OF A MUCH COOLER AIRMASS FOR THE WEEKEND. UPPER LEVEL LOW OVER SOUTHERN CANADA WILL APPROACH WESTERN ONTARIO TUESDAY MORNING. SEVERAL WEAK SHORTWAVES TRACKING THROUGH THE LONGWAVE TROUGH AND HEIGHT FALLS ASSOCIATED WITH THE LOW WILL CONTINUE TO BREAK DOWN THE RIDGE OVER THE EASTERN CONUS. THE FRONT WILL BE DRAPED ACROSS MID MI BY TUESDAY MORNING WITH THE PRECIPITATION EVENT WELL ON ITS WAY. A SHORTWAVE IS PROGGED TO LIFT ALONG THE FRONT EARLY TUESDAY WHICH WILL DEVELOP A SFC LOW NEAR IOWA. THIS WILL LIFT THE FRONT BACK NORTHWARD TEMPORARILY AS A WARM FRONT...KEEPING THE HIGHEST POPS ACROSS THE SAGINAW VALLEY. THIS SFC LOW WILL LIFT NE THROUGH MID MI TUESDAY EVENING WHICH WILL SIGNAL THE START OF A MORE PROGRESSIVE SYSTEM OVERALL OWNING TO A STRONG UPPER JET MAX COMING ASHORE BRITISH COLUMBIA MONDAY NIGHT AND SURGING AROUND THE UPPER LOW. THIS WILL FORCE THE COLD FRONT ACROSS LOWER MI LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. THIS SYSTEM OVERALL WILL BE A VERY EFFICIENT RAIN MAKER AS PWATS LOOK TO HOVER JUST SHY OF 2 INCHES THROUGH THE DURATION OF THE EVENT. STEADY AND STRONG 850MB LL JET WILL CONTINUALLY FEED MOISTURE NORTHWARD AHEAD OF THE FRONT. IMPRESSIVE LL THETA E FIELD AS WELL WITH AN ENHANCED RIBBON OF WARM/MOIST AIR JUST SITTING OVER THE STATE. INSTABILITY WILL NOT BE TOO GREAT BUT A TALL SKINNY CAPE PROFILE WOULD FAVOR HEAVY RAINFALL. POPS WILL BE DEPENDENT ON SHORTWAVE ACTIVITY...PULSES IN THE LL JET...AND FLUCTUATIONS IN THE FRONTAL BOUNDARY SO GENERALLY SPEAKING...LIKELYS WILL BE FEATURES ACROSS THE NORTH WITH CHANCE POPS FURTHER SOUTH WITH FUTURE UPDATES PEGGING THE SMALLER SCALE FORCINGS. SHOWERS WILL DOMINATE BUT SOME ISOLATED/EMBEDDED THUNDERSTORMS CANNOT BE RULED OUT. BEST CHANCES FOR THUNDERSTORMS WILL BE WITH THE ACTUAL FROPA WEDNESDAY MORNING. TEMPERATURES WILL BE TRICKY TUESDAY AS THE FRONTAL LOCATION AND EXCESSIVE CLOUDS ACROSS THE NORTH WILL LIKELY LEAD TO A HEALTHY GRADIENT ACROSS SE MI. SHOULD STILL BE ABLE TO GET INTO THE MID/UPPER 80S ACROSS THE SOUTH AND DETROIT METRO WITH ONGOING SHOWERS AND CLOUDS KEEPING LOCATIONS FURTHER NORTH CLOSER TO 80 OR EVEN IN THE UPPER 70S. PASSAGE OF THE COLD FRONT WILL BRING ABOUT SOME NOTABLE CHANGES FOR THE REMAINDER OF THE LONG TERM. MUCH COOLER AND DRIER AIR WILL FEED INTO THE AREA WITH NORTHERLY FLOW. A WAVE DIVING INTO THE BASE OF THE LONGWAVE TROUGH WILL THEN DEEPEN AND CUTOFF AS IT REACHES THE GREAT LAKES FOR THE WEEKEND. 850MB TEMPS ARE FORECAST TO FALL BACK INTO THE SINGLE DIGITS WITH HIGH TEMPERATURES IN THE LOW 70S...AND POSSIBLY THE UPPER 60S FRIDAY AND SATURDAY. SHOWERS WILL BE POSSIBLE STARTING FRIDAY NIGHT ASSOCIATED WITH THE BROAD LIFT FROM THE UPPER LEVEL LOW AND ANY SFC PRESSURE FALLS WITH IT. MARINE... SOUTHWESTERLY WINDS WILL BECOME TODAY AHEAD OF AN APPROACHING FRONT. THIS SLOW MOVING FRONT WILL BRING A CHANCE OF SHOWERS THIS MORNING FOR NORTHERN LAKE HURON AND LATER THIS AFTERNOON FURTHER SOUTH. A THUNDERSTORM CANNOT BE RULES OUT BUT NOT EXPECTING ANYTHING STRONG OR WIDESPREAD. A SURFACE LOW WILL THEN TRACK THROUGH THE AREA LATE TUESDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS THROUGH EARLY WEDNESDAY. A PERIOD OF GUSTY SOUTHWEST WINDS WILL BE POSSIBLE ON TUESDAY AS THIS LOW PASSES THROUGH NORTHERN LOWER MICHIGAN. THIS WILL BE ESPECIALLY TRUE OVER SAGINAW BAY DUE TO FUNNELING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......SF AVIATION.....JVC SHORT TERM...JVC LONG TERM....DRK MARINE.......DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1257 AM EDT MON SEP 7 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 327 PM EDT SUN SEP 6 2015 A SHORTWAVE THAT MOVED THROUGH LAST NIGHT INTO THIS MORNING PRODUCED HEAVY RAIN OVER WRN LAKE SUPERIOR AND MN...AND EVEN BROUGHT SHOWERS AND THUNDERSTORMS TO FAR WRN UPPER MI AND ERN LAKE SUPERIOR. OVER MOST LAND AREAS...AN EML WAS TOO STRONG TO ALLOW CONVECTION TO CONDITIONS...WITH ONLY A FEW DROPS HAVING FALLEN AT WFO MQT TODAY AS A ROGUE SHOWER PASSED BY. CLOUD COVER HAS BEEN MORE EXTENSIVE DUE TO THE MORNING CONVECTION...AS WELL AS CONVECTION UPSTREAM OVER WI THAT HAS SENT HIGH CLOUDS OVER MUCH OF THE AREA. THIS HAS BROUGHT DOWN MAX TEMPS A FEW DEGREES FROM WHAT WAS PREVIOUSLY EXPECTED. STILL...MUGGY CONDITIONS PERSIST AS LOW-MID 80S TEMPS AND LOW 70S DEW POINTS ARE BEING OBSERVED. MODELS HAVE NOT PERFORMED WELL ALL DAY...EVEN THE HRRR HAS CONTINUED TO INITIALIZE WITH HEAVY PRECIP OVER WRN UPPER MI WHERE NON EXISTS. THIS SEEMS LIKELY DUE TO AN UNDERESTIMATION OF BOTH THE STRENGTH OF THE EML/CIN AND POOR HANDLING OF MORNING PRECIP/CLOUD COVER. LATEST RUNS OVER MANY HIGH-RES MODELS ARE NOW DOING A DECENT JOB WITH QPF OVER THE CWA AT THE PRESENT...BUT ARE VERY POOR IN THEIR HANDLING OF UPSTREAM CONVECTION OVER NERN MN (ASSOCIATED WITH A COLD FRONT MOVING SE) AND CONVECTION OVER WRN WI AND SOUTH MN AHEAD OF A SHORTWAVE AND WEAK SFC LOW NEAR THE MN/SD BORDER. THE HRRR IS HANDLING UPSTREAM CONVECTION WELL...AND IT ALSO IS SIMILAR TO THE OTHER MODELS BY TIME THE NEXT ROUND OF CONVECTION MOVES IN MAINLY AFTER 00Z THIS EVENING. THIS LENDS GREATER CONFIDENCE TO OTHER MODELS...SO WILL USE THEN SINCE THEY ALSO ARE DOING WELL NOW. MAIN MODELS USED ARE THE NAM...NAM DNG...REGIONAL GEM...NCEP HIGH-RES WRF ARW AND NMM. SHOWERS AND THUNDERSTORMS WILL MOVE IN AFTER 00Z THIS EVENING AS THE SHORTWAVE EJECTS INTO THE AREA AND THE SFC LOW MOVES THROUGH THE N...DRIVING THE COLD FRONT THROUGH. HEAVY RAIN IS EXPECTED IN ANY THUNDERSTORMS DUE TO WELL ABOVE NORMAL MOISTURE/PWATS. OTHER THREATS ARE POSSIBLY LARGE HAIL AND DAMAGING WINDS...MAINLY OVER THE W. MUCAPES OF 1000-1500J/KG (MAINLY THIS HIGH OVER THE W) AND 0-6KM BULK SHEAR AROUND 30 ARE MARGINAL VALUES...SO SOME STRONG TO SEVERE STORMS ARE POSSIBLE OVER THE W...BUT NOT LIKELY. STILL SOME UNCERTAINTY MON. MODELS GENERALLY AGREE THAT MOST OF THE PRECIP WILL BE E OF THE CWA BY 18Z...EXCEPT MAYBE A COUPLE NUISANCE SHOWERS OVER THE E. HOWEVER...THE NAM AND NCEP HIGH-RES WRF NMM ARE SHOWING CONVECTION BREAKING OUT IN THE AFTERNOON OVER ERN UPPER MI. HOWEVER...DID NOT INCORPORATE THAT INTO THE FORECAST AT THIS TIME AS THOSE MODELS SEEM TO BE OVERDOING SFC TEMPS AND INSTABILITY. SKIES SHOULD CLEARING FROM THE W...LAGGING THE LONGEST OVER THE E NEAR LAKE SUPERIOR. HIGHS SHOULD BE IN THE 70S TO AROUND 80...WARMEST FAR SOUTH CENTRAL. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 449 PM EDT SUN SEP 6 2015 MONDAY NIGHT THROUGH TUESDAY...THE GFS AND ECMWF WERE IN RELATIVELY GOOD AGREEMENT WITH THE STRENGTH/POSITION OF THE SHORTWAVE MOVING OUT OF THE PLAINS TOWARD THE GREAT LAKES THAT SUPPORTS DEVELOPMENT OF A SFC WAVE ALONG THE FRONT. WITH MOST OF THE PCPN TO THE SOUTH OF THE CWA...CHANCE POPS WERE MAINTAINED FOR THE SE HALF...ESPECIALLY ALONG LAKE MICHIGAN. TUE NIGHT INTO WED...HIGH PRES WILL BUILD INTO THE WRN LAKES TUE NIGHT INTO WED WITH CLEARING SKIES. LOOK FOR TEMPS NEAR SEASONAL AVERAGES WITH LOWS AROUND 50 TO 55 AND HIGHS AROUND 70. THU-FRI...THE GFS/GEFS/ECMWF REMAIN IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVE TROUGH DIGGING TOWARD THE UPPER MS VALLEY WED NIGHT AND THROUGH THE NRN LAKES THU. ELEVATED INSTABILITY MAY BE MARGINAL FOR TSRA...BUT WITH MODERATE TO STRONG DEEP LAYER QVECTOR CONV AND FAVORABLE MOISTURE TRANSPORT...AT LEAST ISOLD TS WILL BE POSSIBLE. THE 12Z ECMWF HAS TRENDED BACK TOWARD A DEEPER TROUGH INTO THE GREAT LAKES BY FRI WITH DEEP MOISTURE AND NRLY CYCLONIC FLOW THAT WOULD SUPPORT SHOWERS AND LAKE ENHANCED RAIN INTO UPPER MI. EVEN THOUGH GFS IS MORE PROGRESSIVE AND NOT AS DEEP WITH THE TROUGH...850 MB TEMPS TO AROUND 2C (LAKE TEMPS AROUND 15C) MAY STILL BE COLD ENOUGH TO PRODUCE SOME LAKE EFFECT PCPN. MORE FALL-LIKE CONDITIONS ARE EXPECTED WITH HIGHS ONLY IN THE UPPER 50S AND LOWER 60S FRI. SAT-SUN...ALTHOUGH A TRANSITION BACK TOWARD A MORE ZONAL PATTERN IS EXPECTED WITH MODERATING TEMPS SAT...THERE IS UNCERTAINTY WITH THE AMOUNT OF HEIGHT FALLS INTO THE NRN CONUS ASSOCIATED WITH A SHORTWAVE MOVING TOWARD HUDSON BAY OR NW ONTARIO. THE 12Z/6 ECMWF...UNLIKE THE DRY GFS AND 00Z/6 ECMWF DROPS A SHORTWAVE AND FRONT WITH PCPN INTO THE NRN LAKES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1257 AM EDT MON SEP 7 2015 SHRA/TSRA...SOME WITH VERY HEAVY RAINFALL...WILL CONTINUE TO SPREAD E ACROSS THE AREA OVERNIGHT IN ASSOCIATION WITH A COLD FRONT. PRECIPITION WILL BE ENDING AT KIWD/KCMX IN THE NEXT FEW HRS...WHILE HEAVIER PCPN WILL AFFECT KSAW FOR THE NEXT COUPLE OF HRS. EXPECT IFR/LIFR CONDITIONS TO DEVELOP AT KIWD/KCMX DURING THE NIGHT...WITH KSAW FALLING TO LIFR AROUND SUNRISE. IMPROVEMENT TO VFR WILL OCCUR FROM W TO E AT ALL TERMINALS FROM LATE MORNING THRU MID AFTN AS DRIER AIR ARRIVES BEHIND COLD FRONT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 327 PM EDT SUN SEP 6 2015 FOG WILL REMAIN A CONCERN UNTIL THE FRONTAL PASSAGE LATE TONIGHT AS HIGH DEW POINTS KEEP MOVING ACROSS THE COLDER WATER. SOUTH WINDS TODAY WILL TURN WESTERLY ON MONDAY THEN DECREASE MON NIGHT INTO TUE. OVERALL...NEXT WEEK LOOKS FAIRLY QUIET ON THE LAKE WITH NO MAJOR SYSTEMS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...TITUS LONG TERM...JLB AVIATION...ROLFSON MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
909 PM CDT TUE SEP 8 2015 .UPDATE: Issued at 850 PM CDT Tue Sep 8 2015 Have updated forecast to pull precip further S as cdfnt continues to slowly move swd. Precip along the fnt shud fill in a little more to the E over night. Overall, have trended twd the RAP soln which keeps most of the precip across sern portions of the CWA by sunrise Wed morning. && .SHORT TERM: (Through Late Tonight) Issued at 210 PM CDT Tue Sep 8 2015 Cold front really struggling to make too much progress south today and is currenlty aligned from near Kansas City to the Quad Cities. Precipitation trends remain the focus for the forecast. Area of showers and thunderstorms continue to slowly progress south on outflow from last nights convection that occurred to our northwest. This is well out ahead of the front and away from any deep layer flow aloft so severe chances have been largely removed. More convection is forming back across central Kansas and think this wave of precipitation will replace ongoing activity overnight and into tomorrow morning. CVKING .LONG TERM: (Wednesday through Next Tuesday) Issued at 210 PM CDT Tue Sep 8 2015 Upper level trof axis, currently extending from the upper Midwest to the central Plains, will move east over the next 24 hours forcing the cold front south through the area and ending the threat of precipiation from northwest to southeast. Temperatures should cool to near normal values Wednesday and Thursday before a stronger cold front arrives Thursday night and Firday. Have some chance PoPs with the front, but think focus may remain west of the CWA. Autumn temperatures arrive for the weekend with highs in the 70s and lows dipping into the upper 40s and lower 50s. CVKING && .AVIATION: (For the 00z TAFs through 00z Wednesday Evening) Issued at 652 PM CDT Tue Sep 8 2015 Cold front is thru KUIN and will slowly push southeastward tonight, getting thru KCOU later this evening and STL metro sites overnight. SHRA/TSRA trying to fire along it and should eventually fill in later this evening but by this time should also be limited with any thunder. While with early passage of cold front thru KUIN, that should spare them much in the way of low CIGs, low CIGs currently only near the front should expand in coverage tonight and linger, especially over the STL metro sites. It is also here at the STL metro sites where there will be the best potential for IFR CIGs and will be monitored closely for possible amendments. Clouds that do form will be slow to pull out, with non-VFR CIGs expected well into the day Wednesday with diurnal enhancements as it becomes more of a broken cumulus cloud field. Eventually clearing is anticipated by Wednesday evening. Winds will be light throughout, becoming northerly behind front. Specifics for KSTL: VFR conditions will transition to MVFR with rain filling in later this evening. IFR possible late tonight into Wednesday morning, but will forego mention and monitor for possible amendment later this evening. Otherwise, non-VFR CIGs slow to pull out until mid-late Wednesday afternoon thanks to diurnal enhancements to cloud field but eventually, a return to VFR conditions is expected by nightfall Wednesday night. TES && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1120 PM MDT SUN SEP 6 2015 AVIATION SECTION UPDATED. .DISCUSSION... UPDATE FORTHCOMING. MODELS, INCLUDING HRRR AND RAP13, ALL BEING SOME LIGHT PRECIPITATION OFF THE ROCKY MOUNTAIN FRONT AND OUT OVER THE PLAINS AFTER 06Z AS WEAK SHORT WAVE ENERGY MOVES THROUGH. HAVE ADDED LOW POPS FOR AFOREMENTIONED AREA FOR THIS REASON. REMAINDER OF FORECAST LOOKS GOOD AS DO OVERNIGHT LOWS. && .AVIATION... UPDATED 2320Z. WESTERLY FLOW ALOFT WILL CONTINUE TO BRING MID AND HIGH CLOUDS ACROSS THE AREA. WINDS HAVE DROPPED TO LIGHT AND VARIABLE AT MOST TERMINALS TONIGHT...BUT WEST WIND GUSTS TO AROUND 25KTS WILL REDEVELOP MONDAY. VFR CONDITIONS PREVAIL. && .PREV DISCUSSION...ISSUED 241 PM MDT SUN SEP 6 2015 TONIGHT THROUGH TUESDAY...GUSTY WESTERLY WINDS AFFECTING THE FORECAST AREA THIS AFTERNOON WILL DIMINISH DURING THE EARLY TO MID EVENING HOURS. WEST TO NORTHWEST CYCLONICALLY-CURVED FLOW ALOFT WILL PREVAIL FOR MONDAY AND TUESDAY WITH AFTERNOON HIGH TEMPERATURES REMAINING BELOW SEASONAL AVERAGES. SEVERAL SHORTWAVES MOVING THROUGH THE FLOW ALOFT WILL BRING SCATTERED SHOWERS TO THE MOUNTAINS OF THE CONTINENTAL DIVIDE AND GLACIER PARK, BUT ONLY ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED IN THE PLAINS AND VALLEYS. WINDS REMAIN WESTERLY AND BREEZY BUT ARE NOT EXPECTED TO BE AS STRONG AS THOSE OF TODAY. MPJ TUESDAY NIGHT THROUGH SUNDAY...LITTLE IF ANY SIGNIFICANT WEATHER EXPECTED DURING THIS PERIOD. ONLY WEATHER SYSTEM OF NOTE IS A QUICK- MOVING SHORTWAVE TROF THAT WILL PRODUCE SOME SCATTERED LIGHT RAIN SHOWERS THROUGH CENTRAL MT THROUGH TUES NIGHT. ALSO, RESIDUAL MOISTURE FROM THIS SYSTEM MAY COMBINE WITH NORTHWEST FLOW ALOFT TO GENERATE A FEW SHOWERS AND A THUNDERSTORM OR TWO OVER THE LITTLE BELT AND SNOWY MTNS ON WED AFTN/EVE WHILE REST OF REGION REMAINS DRY. FROM LATE WED ONWARD, HIGH PRESSURE RIDGING WILL SLOWLY BUILD INTO THE NORTHERN ROCKIES, MAINTAINING THE DRY CONDITIONS THROUGH AT LEAST SATURDAY. LATEST FORECAST MODEL RUNS SHOW THE NORTHERN PORTION OF THE RIDGE WEAKENING ON SUNDAY IN RESPONSE TO AN UPPER- LEVEL TROF MOVING THROUGH WESTERN CANADA. HOWEVER, ONLY LIMITED MOISTURE MAKES IT SOUTH OF THE US/CAN BORDER, PERHAPS ENOUGH TO DEVELOP A FEW SHOWERS ALONG THE ROCKY MTN FRONT, BUT DOWNSLOPE FLOW SHOULD KEEP PRECIPITATION FROM FORMING OVER THE PLAINS. AS THE RIDGE MOVES INTO OUR REGION, WE`LL SEE A GRADUALLY WARMING TREND WITH LOW 70S ON THURS INCREASING TO THE LOW 80S FOR SAT. 12Z FORECAST MODELS INDICATE THE POTENTIAL FOR A DISTURBANCE WITH AN ASSOCIATED COLD FRONT TO MOVE THROUGH THE FORECAST AREA ON SUNDAY, BUT THERE IS SOME DISCREPANCY WITH REGARDS TO STRENGTH. HAVE THEREFORE ADDED MENTION OF SHOWERS AND HAVE COOLED SUNDAY`S HIGHS AROUND 5 DEGREES TO ACCOUNT FOR THIS. WARANAUSKAS/COULSTON && .PRELIMINARY POINT TEMPS/POPS... GTF 43 62 42 67 / 10 10 10 10 CTB 40 60 42 64 / 10 20 10 10 HLN 42 64 40 68 / 10 10 20 0 BZN 37 63 36 70 / 0 0 20 0 WEY 23 59 23 62 / 0 0 10 0 DLN 35 62 35 69 / 0 0 10 0 HVR 39 62 41 67 / 10 10 10 10 LWT 41 60 39 68 / 10 10 10 0 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
336 PM CDT MON SEP 7 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 335 PM CDT MON SEP 7 2015 SHORTWAVE ALOFT IS EVIDENT ON WATER VAPOR ACROSS THE CENTRAL ROCKIES. THIS WILL MOVE EAST-NORTHEASTWARD ACROSS THE CENTRAL PLAINS THE NEXT 12 TO 24 HOURS. THUNDERSTORMS STILL ARE POSSIBLE TONIGHT. THINKING IS THAT STORMS WILL DEVELOP THIS AFTERNOON OVER THE HIGHER TERRAIN ACROSS COLORADO AHEAD OF THE SHORTWAVE. EXPECTING THAT STORMS WILL THEN MOVE EAST-NORTHEAST ACROSS MUCH OF THE AREA THIS EVENING. NOT EVERYONE WILL SEE RAIN...BUT A FAIRLY DECENT COVERAGE OF STORMS IS POSSIBLE DUE TO FAVORABLE JET DYNAMICS. SEVERE THREAT IS NOT GREAT DUE TO PERSISTENT CLOUD COVER THAT HAS REMAINED INTACT AND HAS CUT DOWN ON THE AMOUNT OF INSTABILITY PRESENT ACROSS MUCH OF THE AREA. BUT...WITH PLENTY OF SHEAR PRESENT...CAN/T RULE OUT A FEW STRONG OR PERHAPS A SEVERE THUNDERSTORM. OTHERWISE A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATER TONIGHT USHERING IN COOLER AIR FOR TUESDAY...WITH HIGHS IN THE MID TO UPPER 70S ACROSS THE AREA. SOME LINGERING MID LEVEL INSTABILITY WILL BE PRESENT THROUGH TUESDAY MORNING...AND SOME LIFT WILL CONTINUE THROUGH MIDDAY BEFORE JET DYNAMICS WANE...SO WILL CONTINUE THE SLIGHT CHANCE FOR SOME MID LEVEL TYPE SHOWER/ISOLATED THUNDERSTORM ACTIVITY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 335 PM CDT MON SEP 7 2015 IN THE NEAR TERM TODAY NAM WAS BY FAR THE BEST AT HANDLING ONGOING PRECIPITATION. LONG RANGE MODELS WERE SLOWER WITH SOLUTIONS IN THE NEAR TERM. WILL TREND THE FORECAST IN THE MID TERM TOWARDS THE NAM SOLUTIONS AND A BLEND OF GFS AND ECMWF FOR THE EXTENDED WITH BIAS TOWARDS WARMER GFS SOLUTIONS AS ECMWF BRINGS A TROUGH AND SUBSEQUENT CUTOFF LOW INTO THE GREAT LAKES REGION AND AT THE SAME TIME SHEARING THE HUDSON BAY LOW TO THE NORTHEAST. GFS BRINGS A BROAD TROUGH INTO THE EASTERN CONUS WHICH SEEMS MORE REASONABLE FOR THE SEASON. EXTENDED MODELS HAVE BEEN TRYING TO BRING COOLER AIR INTO NORTHERN PLAINS SINCE LAST WEEK AND HAVE CONTINUED TO TREND UP WITH LATER RUNS. TUESDAY EVENING LIGHT SOUTHEAST FLOW AND SURFACE HIGH PRESSURE OVER HEAD AND FRONT WELL TO THE SOUTH OVER SOUTHERN KANSAS...POSSIBILITY FOR SOME LIGHT FOG TOWARDS SUNRISE AS TEMPERATURE DEWPOINT SPREAD DECREASES. HAVE LEFT OUT FOR NOW. WILL TAKE A LOOK ON THE OVER NIGHT SHIFT TONIGHT WHEN I COME BACK IN. LOWS AROUND 50. SURFACE TROUGH BUILDS ALONG THE FRONT RANGE ON WEDNESDAY WITH SOUTHWEST FLOW AND DECENT WAA TEMPERATURES WILL RISE INTO THE LOWER 80S. 25KT 850MB LLJ WITH MID LEVEL FORCING ALONG THE TROUGH AXIS COULD PRODUCE SOME ISOLATED CONVECTION THROUGH THE LATE AFTERNOON AND MOVING EAST INTO THE EVENING AS LLJ INCREASES TO AROUND 50KTS. SOMEWHAT COOLER ON THURSDAY AS SURFACE HIGH PRESSURE BUILDS INTO WESTERN NEBRASKA. MODELS FORMING A WEAK SURFACE LOW ALONG STATIONARY BOUNDARY OVER NORTHWEST KANSAS THROUGH THE DAY FRIDAY INTO SATURDAY MORNING. UPPER WAVE DROPPING A WAVE THROUGH THE NORTHERN PLAINS AS THE SURFACE LOW MOVES SOUTHEAST INTO SOUTH CENTRAL KANSAS WITH THE FRONT. SOUTHEAST ZONES MAY SEE SOME PRECIPITATION BUT WITH THE SURFACE LOW AND THE FRONT MOVING SOUTHEAST HAVE RETAINED SCHC AFTER MIDNIGHT. RIDGE AND WARMER AIR BUILDS EAST INTO WESTERN NEBRASKA SATURDAY SUNDAY AND MONDAY. HIGHS CLIMBING INTO THE MID 80S AND DRY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1248 PM CDT MON SEP 7 2015 VERY DIFFICULT AVIATION FORECAST OVER THE NEXT 24 HOURS FOR THE KLBF AND KVTN TERMINALS. THE FIRST AREA OF CONCERN/DIFFICULTY IS THE PERSISTENCE OF LOW CLOUDS OVER THE KLBF TERMINAL...WITH CURRENT THINKING THAT MVFR CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON HOURS TODAY. THIS CURRENT THINKING IS SUPPORTED BY THE LATEST RUNS OF THE RAP/NAM/AND HRRR MODELS...WHICH KEEP CEILINGS AT OR BELOW 3000FT THROUGH 02Z. THE NEXT AREA OF CONCERN/DIFFICULTY WILL BE THE TIMING ON AFTERNOON/LATE EVENING CONVECTION WITHIN THE GENERAL VICINITY OF THE KLBF AND KVTN TERMINALS. LATEST OPERATIONAL HRRR HAS A LINE OF STORMS MOVING INTO THE SOUTHEASTERN PANHANDLE OF NEBRASKA AND SOUTHWESTERN NEBRASKA BY 00Z THIS EVENING...AND THEN MOVING INTO THE KLBF TERMINAL BETWEEN 02Z AND 05Z. A SECOND AREA OF CONVECTION IS ALSO ANTICIPATED TO FORM OVER NORTHWESTERN NEBRASKA BETWEEN 21Z AND 23Z...BEFORE MOVING EAST INTO THE KVTN TERMINAL BETWEEN 01Z AND 04Z. UNCERTAINTY DOES EXIST WITH SPATIAL COVERAGE OF THIS SECOND AREA OF CONVECTION NEAR KVTN...HOWEVER...CURRENT CLEARING OVER NORTHWESTERN NEBRASKA WOULD SUPPORT THE DEVELOPMENT OF THUNDERSTORMS THIS AFTERNOON. ANOTHER ROUND OF LOW CLOUDS ARE POSSIBLE TONIGHT AGAIN OVER THE KLBF TERMINAL AFTER THE AREA OF SHOWERS/THUNDERSTORMS MOVES THROUGH THIS EVENING. CONFIDENCE IS HIGH ENOUGH AT THIS TIME TO BRING BACK IN MVFR CONDITIONS OVER THE KLBF TERMINAL...WITH EVEN THE CHANCE FOR SOME DRIZZLE AFTER 09Z...HOWEVER...THIS WILL BE HIGHLY DEPENDENT ON HOW MUCH MIXING (WHICH WOULD TEND TO SCOUR OUT THE MOISTURE) OCCURS IN THE ATMOSPHERE ONCE THIS EVENINGS STORMS MOVE THROUGH. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...TAYLOR LONG TERM...POWER AVIATION...MOLDAN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1248 PM CDT MON SEP 7 2015 .SYNOPSIS... ISSUED AT 356 AM CDT MON SEP 7 2015 LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT 500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE ONL AREA DUE TO FOG. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM CDT MON SEP 7 2015 FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG DEVELOPMENT MAY BE INHIBITED SOMEWHAT. PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY. THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON. AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW. FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE FCST AT THIS POINT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 356 AM CDT MON SEP 7 2015 CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A GOOD 5 DEGREES OR MORE. BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN WHETHER FOG/STRATUS WILL DEVELOP OR NOT. WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA. SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER. HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1248 PM CDT MON SEP 7 2015 VERY DIFFICULT AVIATION FORECAST OVER THE NEXT 24 HOURS FOR THE KLBF AND KVTN TERMINALS. THE FIRST AREA OF CONCERN/DIFFICULTY IS THE PERSISTENCE OF LOW CLOUDS OVER THE KLBF TERMINAL...WITH CURRENT THINKING THAT MVFR CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON HOURS TODAY. THIS CURRENT THINKING IS SUPPORTED BY THE LATEST RUNS OF THE RAP/NAM/AND HRRR MODELS...WHICH KEEP CEILINGS AT OR BELOW 3000FT THROUGH 02Z. THE NEXT AREA OF CONCERN/DIFFICULTY WILL BE THE TIMING ON AFTERNOON/LATE EVENING CONVECTION WITHIN THE GENERAL VICINITY OF THE KLBF AND KVTN TERMINALS. LATEST OPERATIONAL HRRR HAS A LINE OF STORMS MOVING INTO THE SOUTHEASTERN PANHANDLE OF NEBRASKA AND SOUTHWESTERN NEBRASKA BY 00Z THIS EVENING...AND THEN MOVING INTO THE KLBF TERMINAL BETWEEN 02Z AND 05Z. A SECOND AREA OF CONVECTION IS ALSO ANTICIPATED TO FORM OVER NORTHWESTERN NEBRASKA BETWEEN 21Z AND 23Z...BEFORE MOVING EAST INTO THE KVTN TERMINAL BETWEEN 01Z AND 04Z. UNCERTAINTY DOES EXIST WITH SPATIAL COVERAGE OF THIS SECOND AREA OF CONVECTION NEAR KVTN...HOWEVER...CURRENT CLEARING OVER NORTHWESTERN NEBRASKA WOULD SUPPORT THE DEVELOPMENT OF THUNDERSTORMS THIS AFTERNOON. ANOTHER ROUND OF LOW CLOUDS ARE POSSIBLE TONIGHT AGAIN OVER THE KLBF TERMINAL AFTER THE AREA OF SHOWERS/THUNDERSTORMS MOVES THROUGH THIS EVENING. CONFIDENCE IS HIGH ENOUGH AT THIS TIME TO BRING BACK IN MVFR CONDITIONS OVER THE KLBF TERMINAL...WITH EVEN THE CHANCE FOR SOME DRIZZLE AFTER 09Z...HOWEVER...THIS WILL BE HIGHLY DEPENDENT ON HOW MUCH MIXING (WHICH WOULD TEND TO SCOUR OUT THE MOISTURE) OCCURS IN THE ATMOSPHERE ONCE THIS EVENINGS STORMS MOVE THROUGH. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JWS SHORT TERM...JWS LONG TERM...MASEK AVIATION...MOLDAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1236 PM CDT MON SEP 7 2015 .UPDATE... ISSUED AT 1037 AM CDT MON SEP 7 2015 A COMPLEX SITUATION TODAY WITH POTENTIAL FOR TSTMS TO DEVELOP OVER THE FCST AREA AS WELL AS MOVE IN FROM THE W. PLEASE SEE THE 1252Z SPC DAY 1 OUTLOOK FOR AN EXCELLENT OVERVIEW OF THE SITUATION. YOU`VE PROBABLY SEEN THE UPGRADE TO A SLGT RISK. WE SAW THIS POTENTIAL YESTERDAY AND BELIEVE IT IS WARRANTED. ALL THE INGREDIENTS ARE THERE. OUR GREATEST CONCERN IS FROM HWY 6 DOWN INTO N-CNTRL KS IN VICINITY OF THE WARM FRONT. SHORT-TERM HI- RES MODELS SUGGEST THE FRONT COULD LIFT BACK N INTO WEBSTER- NUCKOLLS-THAYER COUNTIES. ANY STORMS THAT FORM ON OR NEAR THIS FRONT WILL PROBABLY BE SUPERCELLS AND WILL NEED TO BE CLOSELY MONITORED FOR ALL THREATS. SKYWARN: BE ALERT FOR ACTIVATION IN THE 20Z-21Z TIME FRAME. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 405 AM CDT MON SEP 7 2015 MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST AND WILL ALSO CONTINUE TO ADVERTISE IN THE HWO. WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID AFTERNOON... EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE ACROSS THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH CENTRAL NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE ACROSS THE REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR VALUES UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH YESTERDAY ...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2 PERCENT TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS MENTION TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS BEING THE PRIMARY CONCERNS. TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE 60S ACROSS NORTH CENTRAL KANSAS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 405 AM CDT MON SEP 7 2015 PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH PRECIPITATION CHANCES. THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE SFC... STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING AROUND THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL LIKELY BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT. CONTINUE TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL THUNDERSTORMS. WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE AFTERNOON...HAVE 30-40 POPS GOING ACROSS THE SERN PORTIONS OF THE CWA...CLOSER TO THE MAIN SFC FRONT WHICH LOOKS TO EXTEND FROM EAST CENTRAL TO SOUTH CENTRAL PORTIONS OF KS BY TUES EVENING. HAVE SOME LINGERING 20 POPS DURING THE EVENING HOURS...BUT KEPT THE FORECAST DRY POST-06Z AS THINGS GET PUSHED FURTHER S/SE. CONFIDENCE IN TEMPS FOR TUESDAY IS NOT HIGH...AND WILL BE GREATLY AFFECTED BY LINGERING PRECIP/CLOUDS AS WELL AS THE ULTIMATE LOCATION OF THE SFC BOUNDARY. AT THIS POINT...HIGHS ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S. THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED TO PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW AMPLITUDE/ UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND LIGHT WINDS TO START THE DAY IS EXPECTED TO GIVE WAY TO MORE SOUTHERLY WINDS WITH TIME...AS SFC LOW PRESSURE BECOMES BETTER ORGANIZED TO OUR WEST AHEAD OF THE NEXT UPPER LEVEL SYSTEM APPROACHING THE REGION FROM THE NW. THE LACK OF A NOTABLE CHANGE IN AIR MASS BEHIND THE EARLY WEEK FRONT LOOKS TO KEEP HIGH TEMPS FOR WED IN THE UPPER 70S/LOWER 80S. LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A COUPLE OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW DEVELOPING BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING OFF TO THE EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD BRING A COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT VIA THE ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME FRAME...AND WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT GOING...BUT IF THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE PERIOD WOULD NEED TO HAVE POPS REMOVED. WE SHALL SEE. BOTH SOLUTIONS SHOW ANOTHER SFC COLD FRONT MOVING THROUGH THE REGION...WITH THE ECMWF SHOWING A BETTER PUSH OF COOLER AIR THAN THE GFS AT THIS POINT. FORECAST HIGHS REMAIN A BLEND THURS- SAT...DROPPING BACK INTO THE 70S CWA-WIDE. BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK INTO THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA. && .AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z TUE AFTERNOON) ISSUED AT 1236 PM CDT MON SEP 7 2015 SIGNIFICANT WX ISSUES: +TSRA POTENTIAL MAINLY 22Z-03Z THEN LIFR OR VLIFR STRATUS AND FOG POSSIBLE AGAIN 09Z-15Z TOMORROW. THIS AFTERNOON: A BAND OF SHWRS WITH EMBEDDED THUNDER HAS EXITED EAR AND WILL MOVE THRU GRI BEFORE 19Z. LIFR CIGS SHOULD EVENTUALLY LIFT TO IFR AND EVENTUALLY MVFR. TIMING IS HIGHLY UNCERTAIN. SCT TSTMS WILL ERUPT AFTER 21Z AND THERE IS POTENTIAL FOR 1" HAIL OR LARGER AND G50 KTS IF EITHER TERMINAL TAKES A DIRECT HIT. LIGHT E-NE WINDS UNDER 10 KTS AWAY FROM ANY TSTMS. CONFIDENCE: MEDIUM TONIGHT: TSTMS END WITH A PERIOD OF MULTI-LAYERED VFR CIGS BEFORE IFR STRATUS AND POSSIBLY FOG REDEVELOPS AFTER 06Z. LIGHT NE WINDS UNDER 10 KTS. CONFIDENCE: MEDIUM TUE THRU 18Z: PROBABLY IFR TO START IN FOG/STRATUS WITH GRADUAL IMPROVEMENT TO MVFR BY 18Z. CONFIDENCE: MEDIUM && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...ROSSI LONG TERM...ADP AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1037 AM CDT MON SEP 7 2015 ...MUCH OF THE FCST AREA UPGRADED TO A SLGT RISK OF SVR WX TODAY... .UPDATE... ISSUED AT 1037 AM CDT MON SEP 7 2015 A COMPLEX SITUATION TODAY WITH POTENTIAL FOR TSTMS TO DEVELOP OVER THE FCST AREA AS WELL AS MOVE IN FROM THE W. PLEASE SEE THE 1252Z SPC DAY 1 OUTLOOK FOR AN EXCELLENT OVERVIEW OF THE SITUATION. YOU`VE PROBABLY SEEN THE UPGRADE TO A SLGT RISK. WE SAW THIS POTENTIAL YESTERDAY AND BELIEVE IT IS WARRANTED. ALL THE INGREDIENTS ARE THERE. OUR GREATEST CONCERN IS FROM HWY 6 DOWN INTO N-CNTRL KS IN VICINITY OF THE WARM FRONT. SHORT-TERM HI- RES MODELS SUGGEST THE FRONT COULD LIFT BACK N INTO WEBSTER- NUCKOLLS-THAYER COUNTIES. ANY STORMS THAT FORM ON OR NEAR THIS FRONT WILL PROBABLY BE SUPERCELLS AND WILL NEED TO BE CLOSELY MONITORED FOR ALL THREATS. SKYWARN: BE ALERT FOR ACTIVATION IN THE 20Z-21Z TIME FRAME. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 405 AM CDT MON SEP 7 2015 MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST AND WILL ALSO CONTINUE TO ADVERTISE IN THE HWO. WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID AFTERNOON... EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE ACROSS THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH CENTRAL NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE ACROSS THE REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR VALUES UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH YESTERDAY ...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2 PERCENT TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS MENTION TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS BEING THE PRIMARY CONCERNS. TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE 60S ACROSS NORTH CENTRAL KANSAS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 405 AM CDT MON SEP 7 2015 PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH PRECIPITATION CHANCES. THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE SFC... STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING AROUND THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL LIKELY BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT. CONTINUE TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL THUNDERSTORMS. WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE AFTERNOON...HAVE 30-40 POPS GOING ACROSS THE SERN PORTIONS OF THE CWA...CLOSER TO THE MAIN SFC FRONT WHICH LOOKS TO EXTEND FROM EAST CENTRAL TO SOUTH CENTRAL PORTIONS OF KS BY TUES EVENING. HAVE SOME LINGERING 20 POPS DURING THE EVENING HOURS...BUT KEPT THE FORECAST DRY POST-06Z AS THINGS GET PUSHED FURTHER S/SE. CONFIDENCE IN TEMPS FOR TUESDAY IS NOT HIGH...AND WILL BE GREATLY AFFECTED BY LINGERING PRECIP/CLOUDS AS WELL AS THE ULTIMATE LOCATION OF THE SFC BOUNDARY. AT THIS POINT...HIGHS ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S. THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED TO PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW AMPLITUDE/ UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND LIGHT WINDS TO START THE DAY IS EXPECTED TO GIVE WAY TO MORE SOUTHERLY WINDS WITH TIME...AS SFC LOW PRESSURE BECOMES BETTER ORGANIZED TO OUR WEST AHEAD OF THE NEXT UPPER LEVEL SYSTEM APPROACHING THE REGION FROM THE NW. THE LACK OF A NOTABLE CHANGE IN AIR MASS BEHIND THE EARLY WEEK FRONT LOOKS TO KEEP HIGH TEMPS FOR WED IN THE UPPER 70S/LOWER 80S. LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A COUPLE OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW DEVELOPING BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING OFF TO THE EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD BRING A COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT VIA THE ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME FRAME...AND WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT GOING...BUT IF THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE PERIOD WOULD NEED TO HAVE POPS REMOVED. WE SHALL SEE. BOTH SOLUTIONS SHOW ANOTHER SFC COLD FRONT MOVING THROUGH THE REGION...WITH THE ECMWF SHOWING A BETTER PUSH OF COOLER AIR THAN THE GFS AT THIS POINT. FORECAST HIGHS REMAIN A BLEND THURS- SAT...DROPPING BACK INTO THE 70S CWA-WIDE. BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK INTO THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUE MORNING) ISSUED AT 550 AM CDT MON SEP 7 2015 LOW LEVEL STRATUS HAS MOVED IN ACROSS THE AREA WITH IFR CIGS NOW BEING OBSERVED AT BOTH TERMINALS. WITH THIS LOW STRATUS...MAY NOT SEE VSBYS DROP AS LOW AS PREVIOUSLY THOUGH...BUT WITH A FEW SITES SHOWING IFR VSBYS...OPTED TO INCLUDE THE MENTION OF BR FOR SEVERAL HOURS THIS MORNING. OTHERWISE...EXPECT THE STRATUS TO BE SLOW TO BURN OFF BY LATE MORNING...WITH INCREASING CHANCES FOR THUNDERSTORMS THEREAFTER. OUTSIDE OF ANY THUNDERSTORM ACTIVITY... WINDS ARE EXPECTED TO REMAIN FAIRLY LIGHT TODAY...GENERALLY OUT OF THE EAST OR NORTHEAST AT 10 MPH OR LESS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...ROSSI LONG TERM...ADP AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
642 AM CDT MON SEP 7 2015 .SYNOPSIS... ISSUED AT 356 AM CDT MON SEP 7 2015 LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT 500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE ONL AREA DUE TO FOG. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM CDT MON SEP 7 2015 FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG DEVELOPMENT MAY BE INHIBITED SOMEWHAT. PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY. THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON. AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW. FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE FCST AT THIS POINT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 356 AM CDT MON SEP 7 2015 CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A GOOD 5 DEGREES OR MORE. BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN WHETHER FOG/STRATUS WILL DEVELOP OR NOT. WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA. SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER. HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 642 AM CDT MON SEP 7 2015 VERY DIFFICULT AVIATION FCST FOR THE NEXT 24 HRS. CIRA LOW CLOUD/VIS PRODUCT SHOWING THE LOWER CLOUDS ACROSS PORTIONS OF CENTRAL INTO SW NEB...AND OBS/AREA WEB CAMS SHOWING REDUCTIONS IN VSBY AROUND O`NEILL SWWD TO NEAR BBW. CIGS ARE IFR IN THE ERN AREAS AS WELL WITH MVFR IN THE SW. AC AND SCT SHRA MOVING NEWD ATOP THESE LOWER CLOUDS IN AN AREA OF ELEVATED INSTABILITY. OPERATIONAL HRRR SUGGESTING THESE WILL MOVE OUT BUT NEW DEVELOPMENT NEAR KLBF BY LATE MORNING WOULD OCCUR...AND THIS BACKED UP WITH RAP AND A FEW WRF VERSIONS. HAVE THEREFORE INCLUDED SEVERAL ROUNDS OF PRECIP IN OR NEAR THE KLBF TAF SITE TODAY. FCST SOUNDINGS SHOW LOW CLOUDS AND LOW VSBYS /IFR CONDITIONS/ WOULD STAY EAST OF KVTN TODAY...BUT OVERALL CONFIDENCE IN THIS FCST IS LOW. TIMING OF SUBSEQUENT TSRA WITH FRONT THIS AFTERNOON AND EVENING IS DEPENDANT ON SEVERAL FACTORS INCLUDING HOW MUCH SUNSHINE WILL OCCUR POST MORNING CONVECTION. AFTER NEXT FRONT MOVES THROUGH TONIGHT AND ESSENTIALLY WASHES OUT COULD SEE ANOTHER ROUND OF LOW CLOUDS TONIGHT...BUT AGAIN CONFIDENCE IN THIS SOLUTIONS IS LOW AT THIS POINT AND HAVE THEREFORE NOT INCLUDED IT. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JWS SHORT TERM...JWS LONG TERM...MASEK AVIATION...JWS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
622 AM CDT MON SEP 7 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 405 AM CDT MON SEP 7 2015 MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST AND WILL ALSO CONTINUE TO ADVERTISE IN THE HWO. WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID AFTERNOON...EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE ACROSS THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH CENTRAL NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE ACROSS THE REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR VALUES UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH YESTERDAY...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2 PERCENT TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS MENTION TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS BEING THE PRIMARY CONCERNS. TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE 60S ACROSS NORTH CENTRAL KANSAS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 405 AM CDT MON SEP 7 2015 PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH PRECIPITATION CHANCES. THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE SFC...STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING AROUND THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL LIKELY BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT. CONTINUE TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL THUNDERSTORMS. WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE AFTERNOON...HAVE 30-40 POPS GOING ACROSS THE SERN PORTIONS OF THE CWA...CLOSER TO THE MAIN SFC FRONT WHICH LOOKS TO EXTEND FROM EAST CENTRAL TO SOUTH CENTRAL PORTIONS OF KS BY TUES EVENING. HAVE SOME LINGERING 20 POPS DURING THE EVENING HOURS...BUT KEPT THE FORECAST DRY POST-06Z AS THINGS GET PUSHED FURTHER S/SE. CONFIDENCE IN TEMPS FOR TUESDAY IS NOT HIGH...AND WILL BE GREATLY AFFECTED BY LINGERING PRECIP/CLOUDS AS WELL AS THE ULTIMATE LOCATION OF THE SFC BOUNDARY. AT THIS POINT...HIGHS ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S. THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED TO PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW AMPLITUDE/ UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND LIGHT WINDS TO START THE DAY IS EXPECTED TO GIVE WAY TO MORE SOUTHERLY WINDS WITH TIME...AS SFC LOW PRESSURE BECOMES BETTER ORGANIZED TO OUR WEST AHEAD OF THE NEXT UPPER LEVEL SYSTEM APPROACHING THE REGION FROM THE NW. THE LACK OF A NOTABLE CHANGE IN AIR MASS BEHIND THE EARLY WEEK FRONT LOOKS TO KEEP HIGH TEMPS FOR WED IN THE UPPER 70S/LOWER 80S. LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A COUPLE OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW DEVELOPING BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING OFF TO THE EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD BRING A COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT VIA THE ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME FRAME...AND WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT GOING...BUT IF THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE PERIOD WOULD NEED TO HAVE POPS REMOVED. WE SHALL SEE. BOTH SOLUTIONS SHOW ANOTHER SFC COLD FRONT MOVING THROUGH THE REGION...WITH THE ECMWF SHOWING A BETTER PUSH OF COOLER AIR THAN THE GFS AT THIS POINT. FORECAST HIGHS REMAIN A BLEND THURS-SAT...DROPPING BACK INTO THE 70S CWA-WIDE. BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK INTO THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 550 AM CDT MON SEP 7 2015 LOW LEVEL STRATUS HAS MOVED IN ACROSS THE AREA WITH IFR CIGS NOW BEING OBSERVED AT BOTH TERMINALS. WITH THIS LOW STRATUS...MAY NOT SEE VSBYS DROP AS LOW AS PREVIOUSLY THOUGH...BUT WITH A FEW SITES SHOWING IFR VSBYS...OPTED TO INCLUDE THE MENTION OF BR FOR SEVERAL HOURS THIS MORNING. OTHERWISE...EXPECT THE STRATUS TO BE SLOW TO BURN OFF BY LATE MORNING...WITH INCREASING CHANCES FOR THUNDERSTORMS THEREAFTER. OUTSIDE OF ANY THUNDERSTORM ACTIVITY...WINDS ARE EXPECTED TO REMAIN FAIRLY LIGHT TODAY...GENERALLY OUT OF THE EAST OR NORTHEAST AT 10 MPH OR LESS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ROSSI LONG TERM...ADP AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
426 AM CDT MON SEP 7 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 405 AM CDT MON SEP 7 2015 MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST AND WILL ALSO CONTINUE TO ADVERTISE IN THE HWO. WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID AFTERNOON...EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE ACROSS THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH CENTRAL NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE ACROSS THE REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR VALUES UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH YESTERDAY...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2 PERCENT TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS MENTION TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS BEING THE PRIMARY CONCERNS. TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR SLIGHLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE 60S ACROSS NORTH CENTRAL KANSAS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 405 AM CDT MON SEP 7 2015 PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH PRECIPITATION CHANCES. THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE SFC...STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING AROUND THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL LIKELY BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT. CONTINUE TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL THUNDERSTORMS. WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE AFTERNOON...HAVE 30-40 POPS GOING ACROSS THE SERN PORTIONS OF THE CWA...CLOSER TO THE MAIN SFC FRONT WHICH LOOKS TO EXTEND FROM EAST CENTRAL TO SOUTH CENTRAL PORTIONS OF KS BY TUES EVENING. HAVE SOME LINGERING 20 POPS DURING THE EVENING HOURS...BUT KEPT THE FORECAST DRY POST-06Z AS THINGS GET PUSHED FURTHER S/SE. CONFIDENCE IN TEMPS FOR TUESDAY IS NOT HIGH...AND WILL BE GREATLY AFFECTED BY LINGERING PRECIP/CLOUDS AS WELL AS THE ULTIMATE LOCATION OF THE SFC BOUNDARY. AT THIS POINT...HIGHS ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S. THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED TO PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW AMPLITUDE/ UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND LIGHT WINDS TO START THE DAY IS EXPECTED TO GIVE WAY TO MORE SOUTHERLY WINDS WITH TIME...AS SFC LOW PRESSURE BECOMES BETTER ORGANIZED TO OUR WEST AHEAD OF THE NEXT UPPER LEVEL SYSTEM APPROACHING THE REGION FROM THE NW. THE LACK OF A NOTABLE CHANGE IN AIR MASS BEHIND THE EARLY WEEK FRONT LOOKS TO KEEP HIGH TEMPS FOR WED IN THE UPPER 70S/LOWER 80S. LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A COUPLE OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW DEVELOPING BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING OFF TO THE EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD BRING A COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT VIA THE ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME FRAME...AND WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT GOING...BUT IF THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE PERIOD WOULD NEED TO HAVE POPS REMOVED. WE SHALL SEE. BOTH SOLUTIONS SHOW ANOTHER SFC COLD FRONT MOVING THROUGH THE REGION...WITH THE ECMWF SHOWING A BETTER PUSH OF COOLER AIR THAN THE GFS AT THIS POINT. FORECAST HIGHS REMAIN A BLEND THURS-SAT...DROPPING BACK INTO THE 70S CWA-WIDE. BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK INTO THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1243 AM CDT MON SEP 7 2015 CLEARING SKIES EARLY THIS MORNING COMBINED WITH ELEVATED DEWPOINTS AND LIGHT NORTHEASTERLY WINDS...WILL RESULT IN THE FORMATION OF AT LEAST IFR CIGS/VSBYS TOWARDS 07/10Z. THIS FOG IS EXPECTED TO LINGER FOR SEVERAL HOURS...BEFORE CONDITIONS IMPROVE AFT 07/15Z...OR THEREABOUTS. OTHERWISE...EXPECT THE PRESENCE OF AN OLD FRONTAL BOUNDARY NEAR THE SURFACE AND UPPER LEVEL DISTURBANCE TO PROVIDE THE FOCUS FOR AFTERNOON SHOWER AND THUNDERSTORM DEVELOPMENT...AND OPTED TO INTRODUCE THE CHANCE FOR A VCTS DURING THE LATE AFTERNOON THROUGH EVENING HOURS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ROSSI LONG TERM...ADP AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
400 AM CDT MON SEP 7 2015 .SYNOPSIS... ISSUED AT 356 AM CDT MON SEP 7 2015 LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT 500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE ONL AREA DUE TO FOG. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM CDT MON SEP 7 2015 FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG DEVELOPMENT MAY BE INHIBITED SOMEWHAT. PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY. THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON. AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW. FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE FCST AT THIS POINT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 356 AM CDT MON SEP 7 2015 CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A GOOD 5 DEGREES OR MORE. BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN WHETHER FOG/STRATUS WILL DEVELOP OR NOT. WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA. SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER. HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1144 PM CDT SUN SEP 6 2015 THE POTENTIAL FOR FOG/STRATUS IS THE FIRST AVIATION CONCERN TONIGHT AND EARLY MONDAY. EAST TO NORTHEAST WIND WILL BRING MORE MOISTURE UP THE PLATTE RIVER VALLEY POSSIBLY AS FAR WEST AS OGA BUT LIKELY TO REACH LBF. WE HAVE SOME CONFIDENCE THAT INSTRUMENT METEOROLOGICAL CONDITIONS WILL REACH LBF AND BBW BUT ONLY WEAK CONFIDENCE THAT IT WILL REACH ANY FARTHER WEST. IF IT IS STRATUS THAT COMES IN...THE CEILING IS LIKELY TO BE LESS THAN 1000 FEET WHILE...IF STRATUS DOES NOT COME...VISIBILITY IS LIKELY TO BE LESS THAN 3SM. SHORT TERM OUTPUT FROM ONLY TWO OF THE FIVE MODEL CYCLES GIVES SOME WEAK INSTABILITY AHEAD OF A WEAK UPPER SYSTEM...SO THERE IS A POSSIBILITY OF SHOWERS OR THUNDERSTORMS EARLY MONDAY. HOWEVER...THE DIFFERENCES IN THE MODEL OUTPUT PARES OUR CONFIDENCE TO LESS THAN THIRTY PERCENT THAT THIS WILL OCCUR. LOOKING A LITTLE FARTHER OUT...IT IS POSSIBLE THAT SOME STRONG THUNDERSTORMS WILL DEVELOP LATE AFTERNOON OR EARLY EVENING THOUGH THERE IS CONSIDERABLE UNCERTAINTY WITH THE TIMING AND THE LOCATION. CONSIDERING THE MODEL OUTPUT STATISTICS...ONE BULLETIN INDICATES 20-40 PERCENT PROBABILITY BOTH MONDAY MORNING AND MONDAY EVENING FOR BBW AND LBF AND THE OTHER GIVES THE 20-40 PERCENT PROBABILITY TO THE EVENING ONLY. THUS THE RESULT IS THAT...IF I WERE TO PICK THE TIMING...I WOULD FOCUS ON THE EVENING AFTER 23Z. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JWS SHORT TERM...JWS LONG TERM...MASEK AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1258 AM CDT MON SEP 7 2015 .UPDATE... ISSUED AT 1243 AM CDT MON SEP 7 2015 WINDS ARE SHIFTING EARLY THIS MORNING AND BECOMING MORE NORTHEASTERLY...HELPING TO ADVECT IN HIGHER DEWPOINTS FROM THE NORTHEAST. THIS MORE HUMID AIR...COMBINED WITH CLEARING SKIES AND FALLING TEMPERATURES...SHOULD ALLOW FOR THE FORMATION OF AT LEAST AREAS OF FOG DURING THE EARLY MORNING HOURS. LATEST/04Z RUN OF THE HRRR INDICATES WE COULD SEE WIDESPREAD DENSE FOG AROUND SUNRISE...BUT OPTED TO ONLY UPDATE FORECAST TO INDICATE VISIBILITIES FALLING TO 1 SM FOR THE TIME BEING...BUT WILL NEED TO CONTINUE TO MONITOR IN CASE MORE DENSE FOG DOES INDEED FORM OVERNIGHT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 345 PM CDT SUN SEP 6 2015 ALOFT: THE PERSISTENT WRN USA TROF/ERN USA RIDGE WILL REMAIN THRU TOMORROW...BUT DEAMPLIFICATION WAS UNDERWAY. THE DEEP WRN USA TROF WILL BECOME MORE BROAD AS THE LOW THAT WAS STALLED OVER THE PAC NW THIS PAST WEEK HEADS NE INTO CNTRL CANADA. QUIET SW FLOW WILL REMAIN OVER THE CNTRL PLAINS. HOWEVER...THERE WERE A COUPLE WEAK SHORTWAVE TROFS OVER WA AND NRN CA. AS THESE TROFS CROSS THE NRN ROCKIES TONIGHT AND N OF THE FCST AREA TOMORROW...THIS WILL FORCE THE UPR- LVL JET STREAK TO THE E PUTTING THE FCST AREA IN THE RRQ. MASS ADJUSTMENT/LIFT SHOULD CREATE AN INCREASINGLY FAVORABLE ENVIRONMENT FOR TSTMS MON AFTERNOON. SURFACE: THE COOL FRONT THAT WAS QUASI-STATIONARY WELL NW OF THE FCST AREA THIS PAST WEEK WAS NOW MOVING THRU. AS IT BECOMES PARALLEL TO THE FLOW ALOFT...ITS FWD PROGRESS WILL SLOW AND IT WILL BECOME QUASI-STATIONARY JUST S AND E OF THE FCST AREA TONIGHT. SOME MODELS SUGGEST IT COULD LIFT BACK N INTO S-CNTRL NEB TOMORROW...BUT THERE IS DISAGREEMENT ON THIS. NOW THRU EARLY EVE: HOT S AND E OF THE TRI-CITIES. THE COOL FRONT CURRENTLY EXTENDS FROM COLUMBUS-AURORA-SMITH CENTER-PLAINVILLE KS. WE COULD SEE AN ISOLATED STORM OR TWO DEVELOP...PROBABLY SOMEWHERE FROM GENEVA-YORK-BELOIT. CAN`T RULE OUT A SVR STORM WITH MLCAPE 2000-2500 J/KG...BUT EFFECTIVE SHEAR IS ONLY 25 KTS. TONIGHT: ANY STORMS WILL EXIT EARLY...PROBABLY BY 6 OR 7 PM. WE NEED TO WATCH DEVELOPMENT OF POST-FRONTAL STRATUS. OBS SHOW MVFR CIGS OVER ERN SD AT 20Z. THE NAM 500M DWPT DEPRESSIONS SUGGEST STRATUS FORMS AND SPREADS W ACROSS NEB TONIGHT. EC/GFS/NAM CROSS SECTIONS ALL HAVE IT TO SOME EXTENT. SO EXPECT INCREASING CLOUDS. EVEN IF STRATUS DOESN`T MATERIALIZE...EXPECT EXTENSIVE CIRROSTRATUS/ALTOCU TO OVERTAKE THE AREA AFTER MIDNIGHT FROM THE SW. MON: MODELS ARE TRYING TO DEVELOP HIGH-BASED SHWRS/TSTMS OVER ERN CO LATE TONIGHT...AND BRINGING THEIR REMNANTS E INTO THE FCST AREA DURING THE MORNING. CONFIDENCE IS LOW ON THIS. IT COULD END UP JUST MID-LVL SPRINKLES FROM ACCAS. MODELS SUGGEST SCT TSTMS DEVELOP IN THE AFTERNOON AND THIS SEEMS REASONABLE WITH THE JET DYNAMICS ACTING ON THE FRONT. CLOUD COVER WILL BE A BIG PLAYER IN HOW TSTMS DEVELOP/EVOLVE. 15Z/SREF FCSTS MLCAPE 3000-4000 J/KG...BUT THE SREF COULD BE 3-4F TOO HIGH WITH ITS DWPTS. REGARDLESS...DEEP LAYER SHEAR OF 30-40 KTS WILL SUPPORT ORGANIZED/SUSTAINED UPDRAFTS AND POTENTIAL FOR SVR TSTMS. WITH BACKED WINDS N OF THE WARM FRONT...IF ANY STORMS CAN REMAIN DISCRETE AND FORM ON OR JUST N OF THE FRONT AND/OR DEVELOP IN THE WARM SECTOR AND CROSS THE FRONT...A TORNADO OR TWO WOULD BE POSSIBLE. SPC INDICATED IN THE SWODY2 THAT AN UPGRADE TO SLGT RISK MAY BE NECESSARY. HAVE ALREADY INDICATED POTENT SVR IN THE HWO IN ANTICIPATION OF THIS. TEMPS A TOUGH CALL. THEY WILL DEPEND ON CLOUD COVER. IF STRATUS REMAINS LOCKED BELOW THE FRONTAL INVERSION...SOME AREAS MAY NOT GET OUT OF THE 70S. IT COULD REALLY HEAT UP AGAIN S OF THE FRONT. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 345 PM CDT SUN SEP 6 2015 GUIDANCE SUGGESTS A CLOSED UPPER TROPOSPHERIC LOW WILL EXIST OVER WESTERN AND CENTRAL PORTIONS OF CANADA TO START THE LONG-TERM FORECAST PERIOD AT 00Z TUESDAY...WITH AN ASSOCIATED TROUGH LIKELY EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO PORTIONS OF THE NORTHWESTERN CONUS. THIS UPPER TROPOSPHERIC LOW IS EXPECTED TO MOVE EAST TUESDAY AND WEDNESDAY BEFORE BECOMING STATIONARY OVER THE HUDSON BAY THURSDAY AND FRIDAY. THIS SHOULD ALLOW THE UPPER TROPOSPHERIC TROUGH OVER THE NORTHWESTERN CONUS TO ALSO MOVE EAST ACROSS THE NORTHERN PLAINS...AND PORTIONS OF THE CENTRAL PLAINS...TUESDAY AND WEDNESDAY. AN UPPER TROPOSPHERIC SHORT WAVE...MOVING SOUTHEAST ALONG THE BACKSIDE OF THE LOW...IS THEN EXPECTED TO DIVE SOUTHEAST ACROSS THE NORTHERN AND CENTRAL PLAINS ON THURSDAY...WITH YET ANOTHER SHORT WAVE EXPECTED TO DO THE SAME ON FRIDAY. THIS PARADE OF SHORT WAVES SHOULD THEN CEASE SATURDAY AND SUNDAY AS THE LOW OVER THE HUDSON BAY MOVES EAST/NORTHEAST AND SUBTLE UPPER TROPOSPHERIC RIDGING OVERTAKES THE CENTRAL CONUS. UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE TROUGH ON TUESDAY AND WEDNESDAY COULD BE SUFFICIENT FOR PRECIPITATION PRODUCTION ACROSS MUCH OF OUR AREA MONDAY NIGHT INTO EARLY WEDNESDAY...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS AND EC. GIVEN THIS...POPS REMAIN INTACT ACROSS MUCH OF THE CWA MONDAY NIGHT THROUGH VERY EARLY WEDNESDAY. THE PASSAGE OF THE NEXT TWO SHORT WAVES WILL THEN PROMOTE ADDITIONAL UPPER TROPOSPHERIC THERMAL ADVECTION AND RESULTANT OMEGA THURSDAY AND FRIDAY...AND POPS REMAIN INTACT ACROSS MUCH OF THE CWA ON BOTH OF THESE DAYS AS WELL. DRY CONDITIONS ARE THEN FORECAST SATURDAY AND SUNDAY AS AN OVERALL LACK IN OMEGA OVERTAKES THE AREA. NEAR-NORMAL TEMPERATURE READINGS...WITH HIGHS NEAR 80 AND LOWS IN THE MID TO UPPER 50S...ARE CURRENTLY EXPECTED DURING THE MIDDLE PART OF NEXT WEEK...BUT THE INFILTRATION OF A MUCH COOLER AIR MASS WILL LIKELY RESULT IN BELOW-NORMAL TEMPERATURE READINGS THURSDAY AND BEYOND...WITH HIGHS GENERALLY IN THE 70S AND LOWS NEAR 50 EXPECTED. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1243 AM CDT MON SEP 7 2015 CLEARING SKIES EARLY THIS MORNING COMBINED WITH ELEVATED DEWPOINTS AND LIGHT NORTHEASTERLY WINDS...WILL RESULT IN THE FORMATION OF AT LEAST IFR CIGS/VSBYS TOWARDS 07/10Z. THIS FOG IS EXPECTED TO LINGER FOR SEVERAL HOURS...BEFORE CONDITIONS IMPROVE AFT 07/15Z...OR THEREABOUTS. OTHERWISE...EXPECT THE PRESENCE OF AN OLD FRONTAL BOUNDARY NEAR THE SURFACE AND UPPER LEVEL DISTURBANCE TO PROVIDE THE FOCUS FOR AFTERNOON SHOWER AND THUNDERSTORM DEVELOPMENT...AND OPTED TO INTRODUCE THE CHANCE FOR A VCTS DURING THE LATE AFTERNOON THROUGH EVENING HOURS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...ROSSI SHORT TERM...HALBLAUB LONG TERM...BRYANT AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
302 PM MDT MON SEP 7 2015 .SYNOPSIS... STORMS WILL CONTINUE THIS EVENING LARGELY FOR AREAS SOUTH OF INTERSTATE 40 WHERE SPOTTY LOCATIONS MAY SEE A HALF INCH OR MORE OF RAIN. A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS TUESDAY AND TUESDAY NIGHT BEFORE PUSHING THROUGH THE GAPS OF THE CENTRAL MOUNTAIN CHAIN WEDNESDAY MORNING. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE BEHIND THE FRONT ACROSS THE PLAINS. TEMPERATURES WILL COOL IN THE WAKE OF THE FRONT...BUT WILL STILL BE RIGHT AROUND NORMAL VALUES FOR EARLY SEPTEMBER WEDNESDAY AFTERNOON. MID LEVEL DRY AIR WILL CONTINUE TO PUSH INTO THE STATE ON THURSDAY AND FRIDAY...BUT ANOTHER BACK DOOR FRONT WILL BE LURKING AS WELL. && .DISCUSSION... MOST OF THE RATHER WELL-BEHAVED STORMS TODAY HAVE STAYED SOUTH OF I-40 AS EXPECTED. HRRR SUGGESTS THAT THE ABQ METRO AREA MAY SEE SOME ACTION SHORTLY AFTER 00Z...BUT MOST OF THE ACTIVITY SHOULD END BY MIDNIGHT ACROSS ALL AREAS. STILL LOOKING FOR A BACK DOOR COLD FRONT TO MOVE INTO AT LEAST NE NM ON TUESDAY BEFORE SLIDING SOUTH AND WEST TUESDAY NIGHT. THE FRONT CONTINUES TO LOOK STRONGER WITH EACH MODEL RUN...AND A BREEZY EAST CANYON WIND NOW LOOKS MORE LIKELY EARLY WEDNESDAY MORNING FOR THE RIO GRANDE VALLEY. THE BIGGEST QUESTION CONTINUES TO BE HOW MUCH PRECIPITATION WILL ACCOMPANY THE FRONT. GFS CONTINUES TO BE VERY BULLISH BREAKING OUT STORMS ACROSS MUCH OF EASTERN NM IN MOIST UPSLOPE FLOW TUESDAY NIGHT. OTHER MODELS ARE LESS ENTHUSED. IT CERTAINLY SEEMS POSSIBLE SINCE MODELS ARE NOT SHOWING AS MUCH DRYING AT MID LEVELS AS THEY WERE YESTERDAY...EXCEPT FOR IN THE FAR NW. GIVING A NOD TO THE GFS ENSEMBLE MEMBERS...WHICH ARE MUCH LIKE THEIR OPERATIONAL COUNTERPART... BUMPED UP POPS A BIT MORE ACROSS THE EAST. MOST MODELS NOW SHOWING CONVECTION ALONG THE CENTRAL MTN CHAIN ON WEDNESDAY AFTERNOON WITH CONTINUED MOIST UPSLOPE FLOW. STORMS SHOULD BE MORE ROBUST SOUTH OF I-40 WHERE MID LEVEL DRYING IS NOT AS PREVALENT. HIGH TEMPERATURES ON WEDNESDAY SHOULD DROP AT LEAST 3 TO 8 DEGREES FROM TUESDAYS READINGS...THOUGH THIS WILL MEAN TEMPS WILL ACTUALLY BE RIGHT AROUND NORMAL. THE MID LEVEL DRY AIR NUDGES IN FARTHER ON THURSDAY...AND CONVECTIVE COVERAGE SHOULD WANE A BIT. AREAS SOUTH OF HWY 60 SHOULD HAVE THE BEST STORM CHANCES. THEREAFTER...CONFIDENCE REMAINS VERY LOW AS MODELS CONTINUE TO YO-YO THE NEXT BACK DOOR FRONT AROUND. THE ECMWF IS BACK ON SCHEDULE FOR THE FRONT TO ARRIVE ON FRIDAY...WHILE THE GFS IS AROUND 12 HOURS LATER AND ALSO MUCH STRONGER. THIS WILL OBVIOUSLY HAVE SERIOUS IMPLICATION ON POPS AND TEMPS...SO GENERALLY WENT FOR A MIDDLE OF THE ROAD FORECAST FOR NOW. 34 && .FIRE WEATHER... HIGH PRESSURE ALOFT IS FORECAST TO BUILD INTO THE GREAT BASIN THIS WEEK...EVENTUALLY CUTTING OFF THE FLOW OF MOISTURE FROM THE SOUTH...WHILE SHUNTING HURRICANE LINDA WEST OF BAJA CA/SOCAL. THIS SHOULD LEAD TO A DRYING TREND FOR WESTERN NEW MEXICO. LOW LEVEL MOISTURE WILL SLOSH BACK AND FORTH OVER CENTRAL AND EASTERN NEW MEXICO THIS WEEK...DEPENDING ON TIMING OF 2 BOUNDARIES...ONE EXPECTED TUESDAY/TUESDAY NIGHT AND A SECOND...WHICH THE GFS IS NOW PORTRAYING AS STRONGER THAN IT HAS IN SEVERAL RUNS...ON FRIDAY/FRIDAY NIGHT. SO FAR THIS AFTERNOON...MOST OF THE CONVECTION HAS BEEN RELEGATED TO AREAS ALONG AND SOUTH OF INTERSTATE 40...AS THE HRRR SUGGESTED. WETTING RAIN FOOTPRINTS TO BE FAIRLY SMALL AS CELLS TRACK TO THE EAST/NORTHEAST...AND ACTIVITY IS INDICATED TO DIMINISH BY MID EVENING. TUESDAY/WEDNESDAY ARE TRANSITION DAYS IN WHICH THE UPPER AIR PATTERN SHIFTS FROM WEST TO NORTHWEST/NORTH WINDS ALOFT...IMPORTING CONSIDERABLY DRIER AIR AT THE MID LEVELS. THE SURFACE BOUNDARY FOR TUESDAY/TUESDAY NIGHT APPEARS A BIT MORE VIGOROUS AND MAY PUSH SOME LOW LEVEL MOISTURE INTO THE RGV...WHICH MIXES OUT TO SOME EXTENT WEDNESDAY...WHEN BEST CHANCES FOR WETTING RAIN WILL BECOME FOCUSED ALONG THE CENTRAL MT CHAIN AND SOUTH OF I-40. PRECIPITATION CHANCES TAPER DOWN THURSDAY INTO FRIDAY...BUT ANOTHER BOUNDARY COULD REPLENISH LOW LEVEL MOISTURE INTO THE CENTRAL/EAST BY SATURDAY. TOWARDS THE END OF THIS WEEK...AND INTO NEXT WEEK...FORECAST VARIABLES CONTINUE TO BE QUITE VARIABLE WITH RUN TO RUN MODEL FLIP FLOPPING. THE 12Z GFS DEVELOPS A VIGOROUS SHORT WAVE/CLOSED LOW ON THE EASTERN PERIPHERY OF THE UPPER RIDGE OVER ERN NM/CHIHUAHUA THIS WEEKEND THEN EJECTS IT NEWD EARLY NEXT WEEK. THE ECMWF HAS OTHER IDEAS...MAINLY A 590 PLUS HIGH CENTER OVER NM. IN FACT...THE DEEP UPPER TROF DEPICTED 24 HRS AGO BY BOTH NEAR 240 HRS HAS VANISHED. KEEPING THE LOW CONFIDENCE IN MIND...HIGH HAINES WILL BE FOUND OVER PORTIONS OF CENTRAL AND WRN NM MID TO LATE THIS WEEK. POOR OVERNIGHT RECOVERIES WILL PLAGUE PORTIONS OF THE NW DURING THIS TIME...AND MIN RH VALUES MAY FALL BELOW 15 PERCENT. HIGHS WILL BE CLOSE TO AVERAGE FOR THE SEASON THROUGH THE UPCOMING WEEKEND. OVERNIGHT LOWS MAY FALL TO NEAR FREEZING AT SOME OF THE NRN MT HIGHER TERRAIN OBS SITES MID TO LATE WEEK. VENT RATES FORECAST TO BE GOOD TO EXCELLENT TUESDAY...THEN DECREASE WEDNESDAY WITH AREAS OF FAIR TO POOR FORECAST ALONG AND SOUTH OF I-40. WIDESPREAD FAIR TO POOR RATES ANTICIPATED FRIDAY CENTRAL AND EAST. && .AVIATION... 18Z TAF CYCLE IN GENERALLY WLY STEERING FLOW FOR CONVECTION. SHORT TERM MODELS SUGGEST A DRIER ENVIRONMENT NW AND NORTH CENTRAL NM WITH SCT SHOWERS AND STORMS ALONG AND SOUTH OF INTERSTATE 40 BEFORE 06Z. THE STRONGER STORMS WILL PRODUCE BRIEF MODERATE TO HEAVY RAIN WITH LCL MVFR CIGS/VSBYS AND OCCASIONAL MT OBSCURATIONS AS WELL AS WND GUSTS TO 40KT. OTHERWISE VFR. && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 56 87 52 87 / 5 0 0 0 DULCE........................... 42 81 40 80 / 5 10 5 10 CUBA............................ 50 79 47 77 / 10 5 5 10 GALLUP.......................... 51 84 45 84 / 20 10 0 0 EL MORRO........................ 49 79 45 79 / 30 20 10 10 GRANTS.......................... 50 82 47 83 / 30 10 5 5 QUEMADO......................... 52 79 50 80 / 30 20 10 20 GLENWOOD........................ 58 86 58 85 / 20 30 20 20 CHAMA........................... 44 77 42 77 / 10 10 10 20 LOS ALAMOS...................... 59 80 55 79 / 20 5 5 10 PECOS........................... 56 79 53 75 / 20 10 10 30 CERRO/QUESTA.................... 51 77 48 75 / 5 10 10 20 RED RIVER....................... 41 70 43 68 / 10 20 20 30 ANGEL FIRE...................... 48 70 45 69 / 10 20 20 20 TAOS............................ 47 80 46 78 / 0 10 5 20 MORA............................ 53 76 49 73 / 20 20 20 20 ESPANOLA........................ 53 85 53 84 / 10 0 0 5 SANTA FE........................ 58 83 56 79 / 10 10 5 20 SANTA FE AIRPORT................ 56 86 55 83 / 10 5 0 10 ALBUQUERQUE FOOTHILLS........... 62 86 61 83 / 20 0 5 20 ALBUQUERQUE HEIGHTS............. 64 88 63 85 / 20 0 0 10 ALBUQUERQUE VALLEY.............. 59 90 62 87 / 20 0 0 10 ALBUQUERQUE WEST MESA........... 60 89 61 85 / 20 0 0 10 LOS LUNAS....................... 59 91 60 88 / 20 0 5 10 RIO RANCHO...................... 62 90 60 87 / 20 0 0 10 SOCORRO......................... 63 88 61 88 / 30 5 10 20 SANDIA PARK/CEDAR CREST......... 57 82 56 79 / 20 5 10 20 TIJERAS......................... 59 85 57 81 / 20 5 10 20 MORIARTY/ESTANCIA............... 51 85 53 81 / 10 5 10 30 CLINES CORNERS.................. 56 82 54 77 / 30 10 10 40 GRAN QUIVIRA.................... 58 83 57 80 / 40 10 10 40 CARRIZOZO....................... 62 88 60 84 / 40 20 20 40 RUIDOSO......................... 58 79 57 75 / 40 30 20 50 CAPULIN......................... 54 79 53 77 / 10 20 20 10 RATON........................... 52 85 51 82 / 10 20 20 10 SPRINGER........................ 53 85 53 81 / 10 20 20 10 LAS VEGAS....................... 53 81 51 77 / 20 20 20 30 CLAYTON......................... 63 85 59 82 / 10 20 20 10 ROY............................. 59 83 56 79 / 10 20 20 10 CONCHAS......................... 66 91 63 87 / 20 10 20 10 SANTA ROSA...................... 65 90 62 85 / 20 10 20 30 TUCUMCARI....................... 66 93 63 87 / 30 20 20 10 CLOVIS.......................... 64 91 63 84 / 30 20 30 20 PORTALES........................ 65 90 63 83 / 30 20 30 30 FORT SUMNER..................... 66 91 64 84 / 30 10 20 20 ROSWELL......................... 68 94 67 88 / 30 10 20 30 PICACHO......................... 62 90 62 83 / 40 20 20 40 ELK............................. 61 81 60 77 / 40 20 20 40 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 34
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1139 PM MDT SUN SEP 6 2015 .AVIATION... 06Z TAF CYCLE SUBTROPICAL MOISTURE WILL SURGE NORTHWARD INTO NM OVERNIGHT INTO MONDAY. EXPECT A SIGNIFICANT UPSWING IN SHOWER AND THUNDERSTORM ACTIVITY BEGINNING LATE MORNING MONDAY AND CONTINUING THROUGH THE AFTERNOON AND EVENING. NW PLATEAU INCLUDING KFMN THE LEAST LIKELY AREA TO EXPERIENCE CONVECTION. MTS OCCASIONALLY OBSCD IN MVFR CIGS/VSBYS WITH THE STRONGER STORMS MONDAY AFTERNOON/EVENING. SFC WND GUSTS TO 40KT POSSIBLE WITH THE STRONGER STORMS. 33 && .PREV DISCUSSION...318 PM MDT SUN SEP 6 2015... .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL CONTINUE TO FAVOR AREAS SOUTH OF I-40 THIS EVENING...BUT STORMS MAY EXPAND FARTHER NORTHWARD ON MONDAY AFTERNOON. DRIER AIR WILL MOVE INTO THE STATE FROM THE NORTHWEST ON TUESDAY AND WEDNESDAY...LIMITING STORMS ACROSS THE NORTHWEST...BUT STORMS ACROSS THE EAST REMAIN POSSIBLE AS A BACK DOOR COLD FRONT SLIDES SOUTHWARD. TEMPERATURES WILL RUN NEAR TO A FEW DEGREES ABOVE NORMAL THROUGH AT LEAST THE MIDDLE OF THE WEEK. FORECAST CONFIDENCE REMAINS LOW ESPECIALLY BEYOND MID WEEK AS MODELS CONTINUE TO FLIP FLOP ON TIMING AND STRENGTH OF ANOTHER BACK DOOR COLD FRONT. && .DISCUSSION... FORECAST CONFIDENCE FOR THE NEXT 7 DAYS IS QUITE LOW DUE TO MODEL INCONSISTENCIES. HENCE...EXPECT CHANGES FROM THE FOLLOWING. GENERALLY...THE UPPER HIGH THAT IS CENTERED OVER WEST TEXAS TODAY WILL SLOWLY SHIFT SOUTH OF NM THROUGH TUESDAY...BEFORE ELONGATING FROM NW TO SE ACROSS SOUTHERN AZ INTO OLD MEXICO. MEANWHILE... TROPICAL STORM LINDA HAS FORMED SOUTH OF THE BAJA AND IS FORECAST TO MOVE NW THRU THIS TIME PERIOD. IT DOES NOT APPEAR AT THIS TIME THAT NM WILL BENEFIT FROM TS LINDAS MOISTURE...AS THE UPPER HIGH WILL BE BLOCKING IT FROM REACHING US. AS FOR THE DETAILS...THAT IS WHERE IT GETS MURKY. FOR TONIGHT...THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CURRENT CONVECTION. THUS...EXPECT THE STORMS ALONG THE SACS TO CONTINUE TO MOVE NEWD THIS EVENING...AS WELL AS ALONG A WEAK CONVERGENCE ZONE ACROSS THE EASTERN PLAINS. THE HRRR ALSO DEPICTS AN UPSWING IN ACTIVITY AFTER MIDNIGHT TONIGHT ACROSS THE SW AND SC AREAS AS A WEAK DISTURBANCE MOVES UP IN SSW FLOW. OTHER MODELS ARE NOT TERRIBLY ENTHUSIASTIC ABOUT THIS FEATURE DURING THE OVERNIGHT PERIOD...BUT IT MAY BE AT LEAST IN PART A REASON WHY THE NAM IS BREAKING OUT MUCH MORE PRECIPITATION ON MONDAY THAN OTHER MODELS...SPECIFICALLY ACROSS THE EAST AND NORTH. THE DEGREE OF DRYING FOR MONDAY DEPICTED BY ANY MODEL ACROSS THE NORTH IS NOT NEARLY AS STRONG AS IT WAS 24 OR 48 HOURS AGO DESPITE THE MORE WESTERLY FLOW ALOFT. SO STANDS TO REASON THAT MONDAY WILL BE MORE ACTIVE THAN TODAY...AND ALSO THAT THE NAM MAY BE ONTO SOMETHING. HOWEVER...THE AMOUNT OF MID AND HIGH CLOUDS THAT MAY BE AROUND DUE TO OVERNIGHT CONVECTION...IF THE HRRR IS RIGHT...MAY DIMINISH SOME OF THE POTENTIAL INSTABILITY. THE DRY AIR DOES APPEAR TO COME INTO AT LEAST THE NW AND PERHAPS NC AREAS ON TUESDAY... WHICH SHOULD LIMIT CONVECTION THERE. THE BACK DOOR FRONT THAT IS EXPECTED TO COME INTO THE NE LOOKS STRONGER... AND MODELS ARE EVEN SHOWING AN INCREASE IN DEWPOINTS ON TUESDAY AND TUESDAY NIGHT BEHIND THE FRONT. THEREFORE...HAVE BUMPED UP POPS SLIGHTLY ACROSS THE SANGRES TO ACCOUNT FOR THE MOIST UPSLOPE FLOW. THE FRONT DOES LOOK TO PUSH FURTHER SOUTH AND WEST THAN WHAT MODELS SHOWED YESTERDAY...PERHAPS EVEN OOZING THRU THE GAPS OF THE CENTRAL MTN CHAIN WED MORNING. WOULD EXPECT THE CENTRAL MTN CHAIN TO HAVE A FAIR AMOUNT OF ACTIVITY ON WEDNESDAY AFTERNOON WITH CONTINUED UPSLOPE FLOW AS THE WINDS SLOWLY VEER AROUND TO THE EAST AND SOUTHEAST ACROSS THE PLAINS...BUT MODELS DO NOT SHOW A CLEAR SIGNAL OF THAT. THIS IS LIKELY BECOMES OF THE DRIER MID LEVEL AIR CONTINUING TO MOVE INTO THE NW HALF OF NM. THUS...THE LOW LEVEL MOISTURE AND UPSLOPE FLOW WILL LIKELY HAVE A FIGHT WITH THE STABILITY AT MID LEVELS. THE STRONG FRONT THAT WAS SUPPOSED TO ARRIVE THURSDAY NIGHT AND FRIDAY...WELL...APPARENTLY THE MODELS HAVE DECIDED THAT IS NOT GOING TO HAPPEN. AFTER SHOWING THAT SCENARIO FOR SEVERAL MODEL RUNS...BOTH THE LATEST EC AND GFS SHOW ONLY A WEAK WIND SHIFT ACROSS THE NE. THUS POP CHANCES DURING THIS PERIOD AND THRU SATURDAY HAVE BEEN TRIMMED CONSIDERABLY. BUT AS STATED AT THE BEGINNING...CONFIDENCE IS QUITE LOW AND MODELS MAY YO-YO BACK TOMORROW. 34 && .FIRE WEATHER... ANOTHER RELATIVELY SLOW DAY FOR CONVECTION SO FAR. SOME DRIER AIR HAS PUSHED INTO THE WEST AND CENTRAL IN THE MID LEVELS ALLOWING LOW LEVEL MOISTURE TO MIX OUT. SHORT TERM MODELS STILL INDICATE LOCALES SOUTH OF INTERSTATE 40 AND ALONG/EAST OF THE PECOS WILL HAVE THE BEST CHANCES FOR WETTING RAIN TONIGHT. IN GENERAL...CELL MOVEMENT WILL AGAIN BE TO THE NORTHEAST FOR THE REST OF THIS AFTERNOON AND TONIGHT. MONDAY FEATURES SOMEWHAT MORE WESTERLY WINDS...AND WITH HIGHER POPS ALONG AND SOUTH OF INTERSTATE 40 AS THE TAP OF MOISTURE IS NOT TOTALLY CUT OFF. OTHERWISE...CONFIDENCE IN THE TIMING OF FRONTS FOR THIS WEEK IS AT AN ALL TIME LOW. THE STRONGER BOUNDARY...AND PUSH OF LOW LEVEL MOISTURE WESTWARD...COULD NOW BE TUESDAY/WEDNESDAY AS THE GFS CONTINUES TO DOWNPLAY THE FRIDAY/SATURDAY BOUNDARY. SO...THERE WILL LIKELY BE A BOUNDARY OR MORE THIS WEEK IMPACTING ERN NM...AND ACCOMPANIED BY SLOSHING OF LOW LEVEL MOISTURE WWD TO THE CENTRAL MT CHAIN AND EVEN INTO THE RGV...BUT WHEN IT WILL HAPPEN THE MODELS CAN/T...SO FAR...SEEM TO PREDICT CONSISTENTLY. THIS WILL IMPACT CHANCES FOR WETTING RAIN TO AT LEAST SOME EXTENT...AND DAY TO DAY CHANGES IN RH AND TEMPERATURES. CURRENT TRENDS THOUGH ARE FOR HIGHER POPS TO SHIFT TO THE CENTRAL MT CHAIN/SOUTHEAST HALF OF THE FORECAST AREA BY MIDWEEK...THEN DIMINISH OVERALL NEXT WEEKEND. WHAT DOES APPEAR LESS VARIABLE IS ADDITIONAL DRYING OF WRN NM FROM THE CONTDVD TO THE AZ BORDER. MID TO LATE WEEK...HIGH HAINES IS FORECAST OVER THIS REGION AND LATE DAY DEW POINTS FALL INTO THE 30S WITH EVEN SOME 20S THE FARTHER NORTH AND WEST YOU GO. CONSEQUENTLY OVERNIGHT RH RECOVERIES LOOK TO BE FAIR TO EVEN POOR NORTHWEST BY THURSDAY/FRIDAY NIGHT WHILE MIN RH VALUES FALL BELOW 15 PERCENT. FORECAST VENT RATES MOSTLY GOOD TO EXCELLENT MONDAY/TUESDAY THEN DECREASE SOME WEDNESDAY/THURSDAY WITH AREAS OF FAIR TO POOR CENTRAL AND NORTH. FORECAST HIGHS WILL RUN WITHIN A FEW DEGREES OF AVERAGE THRU WEDNESDAY/THURSDAY. && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 11
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1000 PM EDT TUE SEP 8 2015 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE THROUGH MIDWEEK AS WEAK LOW PRESSURE DEVELOPS TO THE WEST. A STRONG COLD FRONT WILL APPROACH FROM THE WEST LATE IN THE WEEK AND CROSS THE AREA BY LATE THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 10 PM TUESDAY...PRECIPITATION HAS DISSIPATED ACROSS OUR CWA AND HAVE REMOVED ALL POPS FROM THE FORECAST OVERNIGHT. LATEST RUN OF THE 3KM HRRR AND RUC MODELS INDICATE NO ADDITIONAL PRECIPITATION OVER LAND AREAS OVERNIGHT. WITH HIGH LOW-LEVEL MOISTURE AND LIGHT WINDS...FOG IS A GOOD BET OVERNIGHT. NO CHANGES TO FORECAST TEMPERATURES WITH LOWS AROUND 70 INLAND TO MID 70S BEACHES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... AS OF 2 PM TUE...WEAK UPPER RIDGING OVER THE BAHAMAS/FLORIDA WITH LONG WAVE TROUGHING ACROSS THE UPPER PLAINS/MIDWEST WILL RESULT IN SOUTHWESTERLY FLOW ALOFT. S TO SW SFC SFC WINDS WILL RESULT IN WARM AND MUGGY CONDITIONS ALONG WITH ISOLATED TO SCATTERED DIURNAL SHOWERS AND THUNDERSTORMS...BEST CHANCES ALONG THE SEA BREEZE. COASTAL AREAS SHOULD REMAIN MOSTLY DRY AND THE SEVERE THREAT IS LOW DUE TO WEAK UPPER LEVEL SUPPORT. HIGHS WILL RANGE FROM NEAR 90 INLAND TO MID 80S BEACHES. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... AS OF 315 PM TUESDAY...SUMMERLIKE PATTERN THROUGH THE FIRST PART OF THE LONG TERM PERIOD WITH SCATTERED SHOWERS AND THUNDERSTORMS, THEN A BETTER CHANCE OF PRECIP LATE IN THE WEEK, FOLLOWED BY A POSSIBLE STRONG COLD FRONTAL PASSAGE AND COOLER/DRIER CONDITIONS BY LATE WEEKEND/EARLY NEXT WEEK. THURSDAY THROUGH FRIDAY...LARGE SCALE TROUGH ACROSS THE NORTHERN TIER OF THE CONUS WILL MIGRATE EASTWARD DURING THE PERIOD, WHILE UPR RIDGE AMPLIFIES ACROSS THE INTERMOUNTAIN WEST. THIS WILL INDUCE STRONG DIGGING SHORTWAVE TROUGH ACROSS THE EASTERN US/OHIO VALLEY BY THE WEEKEND. AHEAD OF THIS SYSTEM IN RESPONSE...DEEP LAYER SWRLY FLOW WILL PUMP IN VERY WARM AND HUMID CONDITIONS. WEAK SURFACE FRONT WILL SLOWLY MOVE THROUGH THE GREAT LAKES AREA, SOUTHEAST INTO THE WESTERN SLOPES OF THE APPALACHIAN MOUNTAINS ON THURSDAY. SLIGHTLY BETTER CHANCES FOR ORGANIZED PRECIP AS MOISTURE CONVERGENCE INCREASES OVER THE SOUTHEAST CONUS WITH NEARLY UNIDIRECTIONAL SW FLOW OVER EASTERN NC. MAINTAINED HIGH CHANCE POPS THURSDAY THROUGH FRIDAY FOR INLAND ZONES DUE TO HIGH PWATS AND PIECES OF SHORTWAVE ENERGY ROTATING AROUND STRONGER SHORTWAVE TO THE NORTH AND WEST. THE BULK OF UPPER LEVEL SUPPORT WILL REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL. CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO WITH HIGHS 85-90 AND LOWS IN THE 70S. THIS WEEKEND...THERE ARE STILL SOME DIFFERENCES AMONGST MODEL SUITE IN REGARDS TO EVOLUTION OF THE DIGGING STRONG SHORTWAVE THIS WEEKEND. HAVE CONTINUED TO FOLLOW MORE CLOSELY TO WPC/ECMWF SOLN. A LOOK AT THE ENSEMBLE MEAN HEIGHTS INDICATE THE NCEP/ECM ENSEMBLE MEAN ALONG WITH ECMWF/GEM GLOBAL HAVE FAIRLY UNANIMOUS SUPPORT WITH HANDLING UP UPR LOW/SHORTWAVE POSITIONING ACROSS THE OHIO VALLEY...WHILE DETERMINISTIC GFS STILL A BIT OF AN OUTLIER. THIS WILL KEEP AREA IN THE WARM SECTOR WITH GOOD CHANCES OF SHOWERS AND STORMS ON SATURDAY. WILL RAISE POPS A BIT...INTO THE 40-50 PERCENT RANGE. INCREASING MID AND UPPER SW FLOW COULD BRING A THREAT FOR SEVERE STORMS AS DEEP LAYER SHEAR INCREASES...WITH SEVERE THREAT BEING DEPENDENT ON AMOUNT OF AVAILABLE INSTABILITY. FOR SUNDAY, MORE QUESTIONABLE ON HOW QUICKLY SYSTEM EXITS THE EASTERN CONUS WITH A FASTER FRONTAL PASSAGE SOLUTION BRINGING DRIER AND COOLER CONDITIONS AND A SLOWER SCENARIO KEEPING SHOWER CHANCES THROUGH THE DAY. FOR NOW WILL MAINTAIN THE 30 POPS. MONDAY AND TUESDAY...MONDAY SHOULD BRING A RETURN TO COOLER AND MUCH DRIER CONDITIONS WITH HIGHS IN THE 80-85 RANGE AND LOWS 60-65 INLAND TO 65-70 BEACHES. TD`S WILL BE DOWN INTO THE 50S BRINGING FIRST EARLY TOUCH OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /THROUGH 00Z THURSDAY/... AS OF 650 PM TUESDAY...CONDITIONS BECOMING MORE FAVORABLE FOR DENSE FOG/STRATUS FORMATION LATER TONIGHT. HIGH BOUNDARY LAYER MOISTURE COUPLED WITH NEARLY CALM WINDS WILL LEAD TO PERIODS OF IFR AND PERHAPS LIFR FOG OVERNIGHT ALONG WITH STRATUS. GOOD AGREEMENT IN THE NUMERICAL GUIDANCE AND LOCAL FOG TOOLS SHOWING A HIGH PROBABILITY OF WIDESPREAD LOWER CEILINGS AND VSBYS. CONDITIONS IMPROVE BY MID-MORNING ON WEDNESDAY WITH JUST A FEW WIDELY SCATTERED TSTMS IN THE AFTERNOON. LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/ AS OF 315 PM TUESDAY...GENERALLY VFR THROUGH THE PERIOD, THOUGH OCCASIONAL FOG POSSIBLE EACH NIGHT/EARLY MORNING DUE TO CALM WINDS AND HIGH BOUNDARY LAYER MOISTURE. TEMPO RESTRICTIONS POSSIBLE EACH AFTERNOON DUE TO SCATTERED SHOWERS/THUNDERSTORMS. BETTER CHANCE FOR MORE WIDESPREAD SHOWERS/THUNDERSTORMS LATE WEEK INTO FIRST PART OF THE WEEKEND AHEAD OF A STRONG COLD FRONT. WINDS WILL INC OUT OF THE SW ON THUR AND BECOME GUSTY 12-16 KT. && .MARINE... SHORT TERM /TONIGHT THROUGH WEDNESDAY/... AS OF 10 PM TUESDAY...MINOR ADJUSTMENTS TO WIND DIRECTION AS WINDS ARE GENERALLY SE/S AT SPEEDS OF 10 KNOTS OR LESS WITH SEAS GENERALLY 2 TO 3 FEET WITH SOME LONGER PERIOD SWELL ENERGY. NO CHANGES TO THIS ARE EXPECTED OVERNIGHT. WINDS VEER TO MORE SW BY EARLY WEDNESDAY AS AXIS OF HIGH PRESSURE RIDGE SHIFTS OFFSHORE. SEAS CONTINUE AT 2 TO 3 FEET FOR WEDNESDAY. LONG TERM /WED NIGHT THROUGH SUNDAY/ AS OF 315 PM TUESDAY...GENERALLY GOOD BOATING CONDITIONS CONTINUE THROUGH WEDNESDAY NIGHT, THEN A TIGHTENING SOUTHWESTERLY PRESSURE GRADIENT WILL CREATE MARGINAL CONDITIONS BY THURSDAY THROUGH THE WEEKEND. WINDS WILL BE SW 5-15 KT WEDNESDAY NIGHT THROUGH EARLY THURSDAY, THEN INCREASE TO 10-20 KT LATER THURSDAY, HIGHEST ON THE OUTER PORTIONS OF THE COASTAL WATERS. SEAS WILL GENERALLY BE 3 FEET OR LESS THROUGH EARLY THURSDAY, THEN BUILD 3-5 FT THURSDAY INTO FRIDAY IN RESPONSE TO STRENGTHENING SOUTHWESTERLY WINDS. STRONG COLD FRONT WILL APPROACH BY LATE WEEKEND, THOUGH FORECAST CONFIDENCE STILL RELATIVELY LOW AT THIS TIME DUE TO DISAGREEMENT AMONGST GUIDANCE IN THE FAR EXTENDED PERIOD. CONTINUED AROUND A FOOT HIGHER THAN 12Z WAVEWATCH GUIDANCE AS ITS GFS-BASED WINDS WERE LOWER THAN FCST 15-20 KT SUSTAINED WINDS. CONDITIONS COULD REACH MARGINAL SCA CRITERIA WITH 6 FOOT SEAS FOR A TIME LATE SATURDAY INTO EARLY SUNDAY AHEAD OF THE STRONG COLD FRONT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JAC NEAR TERM...CTC SHORT TERM...JAC LONG TERM...DAG/TL AVIATION...CTC/TL MARINE...CTC/TL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
900 PM EDT TUE SEP 8 2015 .SYNOPSIS...A COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT... THEN WEAKEN TO A TROUGH BEFORE STALLING OVER THE AREA WEDNESDAY THROUGH FRIDAY. A STRONGER COLD FRONT AND UPPER LEVEL LOW WILL APPROACH FROM THE NORTHWEST FRIDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 900 PM TUESDAY... WITH THE LOSS OF HEATING AND GROWTH OF SURFACE-BASED CINH... AND IN THE ABSENCE OF ANY OTHER DYNAMIC OR KINEMATIC FORCING FOR ASCENT... WE`VE SEEN A RAPID DECREASE IN COVERAGE OF TROPICAL-TYPE SHOWERS OVER CENTRAL NC IN THE LAST HOUR. BUT WITH PW VALUES STILL WELL ABOVE NORMAL AROUND 2.0 INCHES AND WEAK BUT PERSISTENT LOW LEVEL MOISTURE TRANSPORT... IT MAY BE A LITTLE WHILE LONGER BEFORE THE SHOWERS ARE COMPLETELY GONE... SO WILL LEAVE IN A MENTION OF ISOLATED SHOWERS FOR ANOTHER FEW HOURS. THE DIMINISHING OF CONVECTIVE CLOUDINESS HAS RESULTED IN PARTIAL OR TOTAL CLEARING OVER MUCH OF CENTRAL NC... BUT SKIES SHOULD TREND BACK TOWARD MOSTLY CLOUDY WITH THE ARRIVAL OF MID AND HIGH CLOUDS FROM THE SOUTH... A REFLECTION OF A STEADY MOISTURE STREAM AROUND THE EAST/NORTH SIDES OF THE UPPER LOW SPINNING JUST SOUTH OF LA... AND WITH THE PROBABLE DEVELOPMENT OF STRATUS OVERNIGHT AS INDICATED BY THE LATEST HRRR AND CANADIAN MODELS. BASED ON THE LATEST HIGH RES GUIDANCE INCLUDING THE HRRR/LAMP/LOCAL WRF... EXPECT LOWS AROUND 70 TO THE LOWER 70S. -GIH && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 305 PM TUESDAY... PRE-FRONTAL TROUGH DEVELOPS IN THE LEE OF THE MOUNTAINS ON WEDNESDAY AS SHORTWAVE TROUGH ATTENDANT SFC COLD FRONT TRACK EAST INTO OHIO AND MS VALLEY. ASIDE FROM THE PRE-FRONTAL TROUGH IN THE WEST AND SEABREEZE BOUNDARY IN THE EAST...WEAK FORCING VIA STRONG DIABATIC HEATING WILL BE THE PRIMARY LIFT/FORCING MECHANISM. WITH SEASONABLY HIGHS PW`S IN THE 1.75-2.0" RANGE...SURFACE HEATING SHOULD LEAD TO AT LEAST ISOLATED TO SCATTERED THUNDERSTORMS. HIGHS IN THE MID TO UPPER 80S. LOWS IN THE UPPER 60S TO LOWER 70S. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 305 PM TUESDAY... A LONG WAVE TROUGH WILL DIG INTO THE MISSISSIPPI RIVER VALLEY TO START THE PERIOD AND WILL PROPEL A FRONT TOWARDS THE REGION BY THURSDAY. MOISTURE WILL INCREASE EVEN MORE AS DEEP SOUTHWESTERLY FLOW SETS UP OVER THE REGION. THIS...ALONG WITH INCREASING FORCING...WILL LEAD TO GOOD CHANCES OF CONVECTION ON THURSDAY. TROUGHING IS THEN PROGGED TO PERSIST OVER THE EASTERN CONUS THROUGH MUCH OF NEXT WEEKEND. ANOTHER SHORTWAVE TROUGH IS THEN PROGGED TO DROP INTO THE OHIO VALLEY OVER THE WEEKEND AND MODELS HAVE COME INTO BETTER AGREEMENT WITH DEVELOPING A CUT OFF LOW BY SUNDAY. (HOWEVER THE ARE STILL INCONSISTENCIES WITH REGARDS TO THE EVOLUTION AND EVENTUAL TRACK OF THIS UPPER LOW). ANOTHER FRONT WILL ACCOMPANY THIS TROUGH...BUT THE TIMING OF THIS FRONTAL PASSAGE IS UP IN THE AIR AT THIS POINT GIVEN THE UNCERTAINTY OF THE UPPER PATTERN. THEREFORE... WILL KEEP ELEVATED PRECIP CHANCES IN THE FORECAST THROUGH THE END OF NEXT WEEKEND (AFTER A BRIEF LULL ON FRIDAY BETWEEN THE TWO SYSTEMS). BY MONDAY...MODELS FINALLY SHOW THE TROUGH PUSHING TO THE EAST OF THE AREA...TAKING PRECIP CHANCES WITH IT (ALTHOUGH THIS IS SUBJECT TO CHANGE GIVEN THE LOW CONFIDENCE IN THE MODELS AND IN FACT THE ECMWF IS MOSTLY DRY BY SUNDAY). GIVEN THE EXPECTED CLOUD COVER/PRECIP THROUGH MUCH OF THE PERIOD...TEMPS SHOULD REMAIN NEAR TO BELOW NORMAL...EXCEPT ON THURSDAY AHEAD OF THE FRONT WHEN MID TO UPPER 80S ARE EXPECTED. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 800 PM TUESDAY... 24 HOUR TAF PERIOD: A COUPLE OF STRAY SHOWERS REMAINING NEAR KFAY BUT OTHERWISE...THE REST OF THE TERMINALS LOOK TO REMAIN DRY FOR THE REMAINDER OF THE EVENING. THE FORECAST PROBLEM OVERNIGHT WILL BE FOG AND LOW STRATUS AND RELATIVE HUMIDITY CROSS SECTIONS...SREF PROBABILITIES AND FORECAST SOUNDINGS ALL SHOW THE POSSIBILITY OF THAT HAPPENING AS DAYBREAK APPROACHES. THEREFORE HAVE INCLUDED THE POSSIBILITY IN THE TAFS AT ALL SITES AFTER 9Z BUT THE SEVERITY OF IT REMAINS UNCERTAIN. FOR NOW HAVE MVFR CONDITIONS IN PLACE BUT SOME PERIODIC IFR/LIFR CONDITIONS CANT BE RULED OUT. EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO BEGIN POPPING UP AFTER 18Z ACROSS THE AREA WITH ALL SITES HAVING A GOOD CHANCE OF SEEING SOME VICINITY SHOWERS AND THUNDERSTORMS. HAVE INCLUDED AS A PROB30 GROUP AT THIS TIME. LONG TERM: A STALLING FRONTAL SYSTEM MOVING INTO THE AREA AND THEN AN UPPER LEVEL LOW WILL KEEP CONDITIONS UNSETTLED FOR THE END OF THE WEEK THROUGH AT LEAST SATURDAY BEFORE A COOLER AND DRIER AIRMASS MOVES IN ON SUNDAY AND INTO EARLY NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...CBL LONG TERM...KRD AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
254 PM EDT MON SEP 7 2015 .SYNOPSIS... A LATE SUMMERTIME PATTERN OF WARM DAYS WITH SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL CONTINUE FOR THE NEXT FEW DAYS. THE NEXT SIGNIFICANT WEATHER SYSTEM TO AFFECT THE AREA WILL BE A COLD FRONT THAT MOVES SLOWLY TOWARD THE AREA THIS WEEKEND AND MAY SLIP OFFSHORE EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM MONDAY...PRECIPITABLE WATER TRENDING UPWARD INLAND PER LATEST SATELLITE-DERIVED BLENDED PWAT SCANS...HAVING NEARLY ERASED THE DRY COLUMN FOOTHOLD OVER INTERIOR NE SC AND SE NC. PRESENTLY LAND CONVECTION HAS SPROUTED AND UNDERWAY...ASSISTED BY A MYRIAD OF UPDRAFT STARTERS INCLUDING OUTFLOW BOUNDARIES...DIFFERENTIAL HEATING AND LOW-LEVEL CONVERGENCE ALONG A WEAK SEA BREEZE BOUNDARY. RECENT KLTX VWP DATA SHOWS EAST WINDS IN THE LOWEST 8KFT WITH SE-S FLOW THROUGH THE MIDDLE AND UPPER LEVELS. IT IS EXPECTED THAT DIURNAL COOLING THROUGH EVENING WILL REMOVE SOME OF THE STEAM FROM CELLS AND A DECREASE IN AREAL COVERAGE INLAND. A TRANSITION TO INCREASED MARINE CONVECTION TONIGHT AS BUOYANCY INCREASES OVER THE WATERS ESPECIALLY INTO VERY EARLY TUESDAY. AS A RESULT MENTIONABLE POPS ARE RETAINED ALONG AND NEAR THE COAST OVERNIGHT. 70-75 MOST LOCATIONS FOR MINIMUM TEMPERATURES TUESDAY DAYBREAK 76-79 BEACHES. PATCHES OF MIST AND FOG CANNOT BE RULED OUT INLAND UNDER PARTIALLY CLEAR SKIES INTO VERY EARLY TUESDAY. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 PM MONDAY...LOW PRESSURE WILL CONTINUE TO RETROGRADE AS RIDGING BUILDS IN FROM THE SOUTHEAST AT LEAST THROUGH EARLY WEDNESDAY. AFTER THIS A SHORTWAVE TROUGH MOVES INTO THE TENNESSEE VALLEY WHICH LOWERS HEIGHTS ONCE AGAIN. AT THE SURFACE A WEAK SOUTHEAST FLOW WILL BE IN PLACE TUESDAY. A BETTER DEFINED PIEDMONT TROUGH WILL DEVELOP WEDNESDAY AFTERNOON. POPS WILL BE MORE RELEGATED TO A SUMMERTIME PATTERN WITH THE LOSS OF THE UPPER LEVEL LOW INFLUENCES. SLIGHT TO LOW CHANCE POPS ARE IN PLACE THROUGHOUT THE PERIOD WITH THE HIGHEST VALUES MOSTLY IN THE AFTERNOONS AND EVENINGS. CONTINUED TO LEAN MORE IN THE DIRECTION OF THE GFS/MAV NUMBERS WHICH ARE VERIFYING MUCH BETTER WITH MORNING LOWS VS THE OTHERS. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 300 PM MONDAY...INLAND SURFACE TROUGHINESS BECOMES ESTABLISHED ON THURSDAY AND A SOUTHWESTERLY RESULTANT SEABREEZE EXPECTED. LOOKING FOR A SLIGHTLY WARM AFTERNOON WITH POSSIBLY DECENT COVERAGE OF CONVECTION. COLD FRONT MOVES IN ON FRIDAY AND LIKELY DECELERATING. RAIN CHANCES WILL TEND TO INCREASE WITH THE APPROACH OF THIS BOUNDARY AND FUTURE FORECAST ITERATIONS MAY BE ABLE TO FINE TUNE WHICH AREAS IF ANY DESERVE HIGHER POPS, HINGING MOST ON THE SPEED OF THE FRONT. THE WEEKEND IS REALLY SHAPING UP TO BE UNSETTLED WITH ANOTHER FRONT MOVING INTO THE SOUTHEASTERN U.S. THIS SECONDARY BOUNDARY WILL BE BEING DRIVING BY AN IMPRESSIVE SYSTEM ALOFT THAT MAY NOT ONLY YIELD HIGHER RAIN CHANCES BUT PERHAPS SOME STRONGER THUNDERSTORMS. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... AS OF 18Z...BIT OF A TRICKY AFTERNOON WITH REGARDS TO CONVECTION. THE HRRR IS NOT VERY ENTHUSED...WITH MAINLY ISOLATED ACTIVITY THROUGH THE AFTERNOON. GIVEN THAT WE ARE AROUND OUR CONVECTIVE TEMP...AND THE FACT THAT THE NAM HAS HIGH POPS...WILL KEEP CONVECTION FAIRLY PREVALENT ALONG THE COAST...PRESSING INLAND AS THE AFTERNOON WEARS ON. NOT SURE IF THE SHOWERS WILL MAKE IT TO THE INLAND TERMINALS SO WILL STICK WITH VCSH. THE NAM IS THE MOST AGGRESSIVE...KEEPING HIGH POPS ALL THE WAY TO 06Z. THINK THIS IS OVERDONE AND WILL DISSIPATE MOST OF THE CONVECTION BY 02-03Z. STRATUS WILL BE REINTRODUCED AFTER MIDNIGHT THROUGH MOST OF THE MORNING HOURS. LOOK FOR THE WINDS TO SHIFT TO SOUTHERLY AS HIGH PRESSURE MOVES OFFSHORE TUESDAY. EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH BRIEF MVFR AND POSSIBLY IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM MONDAY...WINDS TO VEER TO SE-S AND EASE OVERNIGHT AS HIGH PRESSURE ALONG THE NC/VA INLAND BORDER WEAKENS CONSIDERABLY AND THE SYNOPTIC FLOW BECOMES CONTROLLED BY LARGER BERMUDA HIGH PRESSURE FARTHER OFFSHORE. WINDSPEEDS 10 KT OR LESS AFTER MIDNIGHT TONIGHT INTO EARLY TUESDAY SE-S. MARINERS SHOULD CONSIDER OBTAINING A RADAR UPDATE BEFORE VENTURING OUT AS SEVERAL STRONG TSTMS MAY BE CRUISING THE WATERS...MOVING SLOWLY TO THE NW-N TONIGHT AND EARLY TUESDAY. OUTSIDE OF TSTMS SEAS WILL SETTLE TO 2-3 TONIGHT COMPRISED OF ESE WAVES 1-2 FT EVERY 9 AND 12 SECONDS...AND A LIGHT SE CHOP. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 PM MONDAY...SOUTHEAST WINDS AROUND TEN KNOTS SHOULD COVER THE WATERS FOR TUESDAY INTO EARLY WEDNESDAY. A MORE PRONOUNCED PIEDMONT TROUGH WILL INCREASE WIND SPEEDS SLIGHTLY FOR WEDNESDAY INTO A 10-15 KNOT RANGE. WINDS VEER TO THE SOUTHWEST LATE AS A FRONT IN THE TENNESSEE VALLEY EDGES CLOSER. SIGNIFICANT SEAS WILL BE A MIX OF WEAK WIND WAVES AND A VERY MODEST SWELL COMPONANT TEAMING UP TO BRING 1-3 FOOTERS. A FEW FOUR FOOTERS COULD ENTER THE MIX LATE. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 300 PM MONDAY...A DEVELOPING PIEDMONT TROUGH WILL BRING AN INCREASED SOUTHWESTERLY FLOW ON THURSDAY AND THE INTRODUCTION OF SOME 4 FT SEAS ALONG THE OUTER PORTIONS OF THE FORECAST ZONES. THE APPROACH OF A COLD FRONT FROM THE NORTHWEST WILL EASE THE GRADIENT EVEN SO SLIGHTLY PERHAPS EASING THE 4 FT SEAS OUT OF THE FORECAST. THIS BOUNDARY STALLS SOMEWHERE JUST TO OUR WEST WHICH WILL FURTHER ABATE THE GRADIENT IN ADDITION TO VEERING THE FLOW DIRECTION. HOW MUCH OF THE LATTER OCCURS WILL DEPEND ON WHERE THE BOUNDARY DECIDES TO STALL WHICH IS NOT YET CLEAR. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...MJC SHORT TERM...SHK LONG TERM...MBB AVIATION...MJC/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
128 PM EDT MON SEP 7 2015 .SYNOPSIS... LOW PRESSURE ALOFT MOVING ACROSS THE GULF COAST STATES WILL PRODUCE ONSHORE WINDS AND SHOWERS ACROSS THE EASTERN CAROLINAS TODAY. LATE SUMMER CONDITIONS WILL RETURN MID-WEEK AHEAD OF A COLD FRONT APPROACHING FROM THE NORTHWEST. THE FRONT MAY STALL ALONG THE COAST NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 128 PM MONDAY...NO REMARKABLE CHANGES TO THE ONGOING FORECAST. PARTIAL SUNSHINE WILL AID IN BOOSTING LOW-LEVEL CONVECTIVE ENERGY...AND A TRANSITION TO DEVELOPING SHOWERS AND ISOLATED TSTMS OVER LAND SHOULD PREVAIL THROUGH AFTERNOON. IT WILL BE INTERESTING TO SEE HOW THE 3 DEGREES CELSIUS OF WARMING AT 500 MB COMPARED TO YESTERDAY...DUE TO THE RETROGRADING COOL POOL...WILL IMPACT CONVECTIVE BEHAVIOR TODAY. PWAT VALUES OF 1.7-2.0 INCHES WILL BE AMPLE TO RESULT IN POCKETS OF HEAVY RAIN. OUTSIDE OF CELL-TRAINING...STORM MOTION AROUND 15 KT SHOULD LIMIT LOCALIZED FLOODING POTENTIAL. THE PREVIOUS DISCUSSION FOLLOWS. RETROGRESSION OF AN UPPER LOW EVIDENT IN VAPOR MOVIES ACROSS ALABAMA HAS ALTERED THE UPPER WINDS LOCALLY. KLTX VAD WIND PROFILE REGISTERING EAST WIND 15-25 KT FROM 1-9KFT WHILE ABOVE THIS SE 15-20 KT FLOW. THIS WILL PUSH SHALLOWER CONVECTION MORE DIRECTLY EAST WHILE DEEPER TOWERS TRAVEL MORE TO THE NORTHWEST. WEAKENING UPPER PORTIONS OF THE CUMULO-NIMBUS THROUGH ITS LIFE CYCLE WILL BE SPREAD NW OF THE PRIMARY RAIN CORES...ALLOWING LIGHTER STRATIFORM TYPE PCPN/-RA TO REACH AREAS FARTHER INLAND. RECENT AMSU AND SSM/I PWAT LOOPS SHOW THE PRECIPITABLE WATER GRADIENT HAS FILLED IN AND MOISTENED AREAS ALONG AND WEST OF I-95 IN ROUGHLY 43MM/1.7 INCH VALUES...MORE THAN SUFFICIENT VAPOR FOR CONVECTIVE LONGEVITY INLAND. FORMATION OF CONVECTION IS A GOOD BET THIS AFTERNOON AS WELL...AS LAND HEATING RAMPS UP. OUTFLOWS AND DIFFERENTIAL HEATING MECHANISMS WILL BOTH SUPPORT CONVECTIVE INITIATION...AND FORECAST MAXIMUM TEMPERATURES WILL ADD A ZONE OF WEAK LOW-LEVEL CONVERGENCE TO THE MIX ALONG THE COASTAL INTERIOR SEA BREEZE FRONT. DIURNAL COOLING LATE IN THE DAY WILL REMOVE CONVECTIVE INTENSITY AND POP VALUES WILL SHOW A DECLINE THROUGH EVENING...BUT AN UPTREND IN MARINE CONVECTION INTO VERY EARLY TUESDAY POSSIBLY DELIVERING COASTAL SHOWERS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...UPPER TROUGH WILL CONTINUE TO RETROGRADE WESTWARD ACROSS THE GULF COAST STATES TUESDAY...BUT IN A MUCH WEAKER FASHION THAN EARLIER IN THE WEEK. AT THE SAME TIME...RIDGING BLOSSOMING EAST OF FLORIDA WILL EXPAND NORTH INTO THE CAROLINAS TUESDAY AND WEDNESDAY...WHICH WILL LEAD TO LESS UNSETTLED WEATHER ALONG WITH WARMER TEMPERATURES BY MID WEEK. TUESDAY WILL BE THE TRANSITION DAY AND WILL FEATURE A GOOD CHANCE FOR SHOWERS/TSTMS AS THE SURFACE TROUGH SLOWLY ERODES AND LIFTS NORTH...BUT STILL SERVES AS A FOCUS FOR CONVECTION IN AN UNSTABLE ENVIRONMENT WITH PWATS JUST BELOW 2 INCHES. THIS BOUNDARY WILL NOT BE PRESENT ON WEDNESDAY...AND INCREASING HEIGHTS ALOFT WILL INHIBIT STRONG LIFT...BUT A CONTINUED VERY MOIST ENVIRONMENT AND ABOVE NORMAL TEMPERATURES WILL ALLOW FOR MORE TYPICAL DIURNAL CONVECTION ALONG THE SEA BREEZE AND PIEDMONT TROUGH. TEMPS THROUGH MID-WEEK WILL WARM EACH DAY...FROM NEAR SEASONABLE TUESDAY...MID 80S FOR HIGHS AND AROUND 70 FOR LOWS...TO UPPER 80S WEDNESDAY WITH MINS WED NIGHT IN THE LOW TO MID 70S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY....LATE SUMMER HEAT TO RETURN FOR THE END OF THE WEEK AS RIDGING EXPANDS ACROSS THE WESTERN ATLANTIC AND THE EAST COAST...BUT A COLD FRONT WILL APPROACH LATE FRIDAY AND THEN LIKELY STALL ACROSS THE REGION DURING THE UPCOMING WKND. WHILE THE AIR MASS BEHIND THIS FEATURE IS ONLY SUBTLY DIFFERENT FROM THAT OUT AHEAD OF IT...INCREASING CLOUDS AND CONVECTION WILL BRING A RETURN TO COOLER TEMPERATURES WITH MORE UNSETTLED CONDITIONS SATURDAY AND SUNDAY. TEMPS THU/FRI WILL FEATURE A LOT OF READING NEAR 90 DEGREES WITH TYPICAL SUMMERTIME CONVECTION ACTIVITY EXPECTED. AS THE FRONT CROSSES AND STALLS THIS WKND...TEMPS WILL COOL TO BELOW CLIMO BUT CONVECTIVE ACTIVITY WILL RAMP UP WITH A GOOD CHANCE FOR SHOWERS AND TSTMS SATURDAY AND SUNDAY. && .AVIATION /18Z MONDAY THROUGH FRIDAY/... AS OF 18Z...BIT OF A TRICKY AFTERNOON WITH REGARDS TO CONVECTION. THE HRRR IS NOT VERY ENTHUSED...WITH MAINLY ISOLATED ACTIVITY THROUGH THE AFTERNOON. GIVEN THAT WE ARE AROUND OUR CONVECTIVE TEMP...AND THE FACT THAT THE NAM HAS HIGH POPS...WILL KEEP CONVECTION FAIRLY PREVALENT ALONG THE COAST...PRESSING INLAND AS THE AFTERNOON WEARS ON. NOT SURE IF THE SHOWERS WILL MAKE IT TO THE INLAND TERMINALS SO WILL STICK WITH VCSH. THE NAM IS THE MOST AGGRESSIVE...KEEPING HIGH POPS ALL THE WAY TO 06Z. THINK THIS IS OVERDONE AND WILL DISSIPATE MOST OF THE CONVECTION BY 02-03Z. STRATUS WILL BE REINTRODUCED AFTER MIDNIGHT THROUGH MOST OF THE MORNING HOURS. LOOK FOR THE WINDS TO SHIFT TO SOUTHERLY AS HIGH PRESSURE MOVES OFFSHORE TUESDAY. EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH BRIEF MVFR AND POSSIBLY IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 128 PM MONDAY...STEADY EAST-NORTHEAST WINDS EXPECTED ACROSS THE CAROLINA COASTAL WATERS. VEERING WIND DIRECTIONS AND EASING WIND SPEEDS TONIGHT. LOOK FOR SHOWERS AND STORMS MOVING ACROSS THE COASTAL WATERS AND BEACHES MAINLY THIS MORNING...WITH SHOWERS EXPECTED TO DIMINISH IN COVERAGE THIS AFTERNOON. ADDITIONAL SCATTERED SHOWERS AND STORMS ARE POSSIBLE OVERNIGHT. SEAS CURRENTLY 2-4 FEET SHOULD DIMINISH TO AROUND 2 FEET LATE TONIGHT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...BROAD HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CREATE MORE TYPICAL LATE SUMMER CONDITIONS THROUGH MID- WEEK...WITH RETURN FLOW DRIVING STRENGTHENING S/SW WINDS THROUGH THE PERIOD. WINDS THE FIRST HALF OF TUESDAY WILL BE LIGHT AND VARIABLE AS THE PRESSURE PATTERN REMAINS DIFFUSE...BUT AS THE HIGH PRESSURE OFFSHORE BECOMES MORE SIGNIFICANT...A S/SW DIRECTION WILL BECOME PREDOMINANT...AND WIND SPEEDS BY WEDNESDAY WILL RISE TO AROUND 15 KTS. WAVE HEIGHTS TUESDAY WILL BE 1-2 FT AS THE VERY LIGHT WINDS GAIN LITTLE PURCHASE ON SEAS AND SWELL REMAINS INSIGNIFICANT. WAVE HEIGHTS WILL BUILD TO 2-3 FT WITH ISOLATED 4 FTERS POSSIBLE WEDNESDAY ON THE INCREASING WINDS AND A GROWING SE GROUND SWELL. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...HIGH PRESSURE OFFSHORE AND A COLD FRONT APPROACHING FROM THE NW WILL SANDWICH THE COASTAL WATERS THIS PERIOD. THE COLD FRONT WILL BE ON THE DOORSTEP OF THE LOCAL WATERS LATE FRIDAY...BUT ANY WIND SHIFT WILL HOLD OFF UNTIL BEYOND THE EXTENDED. THIS LEAVES SW WINDS THROUGH THE PERIOD...BUT WITH SPEEDS INCREASING TO 15-20 KTS AS THE GRADIENT TIGHTENS. AN E/SE 9-10 SEC SWELL WILL EXIST IN THE WAVE SPECTRUM EACH DAY...BUT WILL BECOME INCREASINGLY SHADOWED BY AN AMPLIFYING 5-SEC SW WIND WAVE. SIGNIFICANT SEAS WILL BUILD THROUGH THE PERIOD...FROM 2-3 FT EARLY THURSDAY TO 3-4 FT ON FRIDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...MJC SHORT TERM...JDW LONG TERM...JDW AVIATION...DL/8
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1008 PM EDT SUN SEP 6 2015 .SYNOPSIS...AN UPPER LEVEL LOW WILL RETROGRADE FROM GA TO THE NORTHERN GULF OF MEXICO TONIGHT...THEN STALL NEAR THE TEXAS GULF COAST THROUGH MID-WEEK. SURFACE HIGH PRESSURE WILL OTHERWISE WEAKEN WHILE EXTENDING WEST INTO NC. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1005 PM SUNDAY... A MID-UPPER LOW OVER GA WILL DRIFT SW AND AWAY FROM CENTRAL NC TONIGHT...WHILE 1022 MB SURFACE HIGH PRESSURE OFFSHORE THE MIDDLE ATLANTIC COAST CONTINUES TO EXTEND SW INTO NC. THE AIR MASS OVER CENTRAL NC IS A STABLE ONE PER 00Z GSO RAOB DATA AND MORE RECENT SPC MESOANALYSIS DATA. GIVEN THE STABILITY AND LACK OF FORCING FOR ASCENT...EXCEPT MOISTURE TRANSPORT AND FRICTIONAL CONVERGENCE ALONG SOUTHEASTERN NC...DRY CONDITIONS ARE EXPECTED OVERNIGHT. BOTH THE HRRR AND SREF SUGGEST LOW CLOUDS ARE LIKELY TO ADVECT/ DEVELOP SOUTHWESTWARD INTO THE WESTERN HALF OR TWO THIRDS OF THE FORECAST AREA TONIGHT...WHICH SEEMS REASONABLE GIVEN A RELATIVE LACK OF LOW CLOUD COVER UPSTREAM IN SE VA AND NE NC...WHERE NWP GUIDANCE SUGGESTS A TONGUE OF DRY AIR WILL EXTEND...AND LATER DRIFT INTO THE COASTAL PLAIN. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 300 PM SUNDAY... THE UPPER LOW IS PROGGED TO BE LOCATED ACROSS THE NORTHEASTERN GULF OF MEXICO BY 12Z MONDAY...BEFORE RETROGRADING EVEN FURTHER TOWARDS THE NORTHWESTERN GULF THROUGHOUT THE DAY. AS A RESULT...ANY WEAK DISTURBANCES THAT ROUND THE EASTERN/NORTHERN PERIPHERY OF THE LOW SHOULD REMAIN SOUTH/SOUTHWEST OF CENTRAL NC. THEREFORE...CONVECTION IS EXPECTED TO BE RATHER LIMITED...OUTSIDE OF ANY DIURNAL ACTIVITY. HIGH TEMPS SHOULD BE SLIGHTLY WARMER GIVEN LESS CLOUDS/PRECIP... GENERALLY MID/UPPER 80S AND OVERNIGHT LOWS WILL BE SIMILAR TO PREVIOUS NIGHTS...WITH UPPER 60S TO NEAR 70 DEGREES EXPECTED. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AS OF 245 PM SUNDAY... CONTINUED RETROGRESSION OF CUTOFF UPPER LOW TO THE SOUTHWEST OPENS THE DOOR FOR DEEPER MOISTURE ADVECTION AS AN UPPER TROF DIGS INTO THE MIDWEST. MEANWHILE...A WEAK SURFACE FRONT WILL BE STALLING OVER THE AREA WEDNESDAY THROUGH FRIDAY...CONCURRENT WITH PRECIPITABLE WATER INCREASING FROM <1.5 INCHES TUESDAY TO 1.75-2 INCHES WEDNESDAY THROUGH FRIDAY. UPPER DYNAMICS ARE NOT PARTICULARLY INVITING FOR CONVECTION EARLY IN THE PERIOD...BUT WOULD EXPECT TO SEE MORE COVERAGE AND ORGANIZATION FRIDAY WHEN THE UPPER TROF SHIFTS FAR ENOUGH EAST TO TIGHTEN UP THE GRADIENTS ASSOCIATED WITH THE STALLED SURFACE FRONT AS WELL AS INCREASING UPPER JET DIFFLUENCE AND ENHANCING UPDRAFT POTENTIAL. WILL MAINTAIN POPS IN THE USUAL DIURNAL PATTERN FROM THE LOW CHANCE CATEGORY TUESDAY INCREASING TO 50% BY FRIDAY. HIGHS WILL BE AT OR SOMEWHAT ABOVE NORMAL...MID TO UPPER 80S THROUGH FRIDAY AFTER MORNING LOWS MOSTLY FROM 65 TO 70. THE UPPER TROF LIFTS OUT AFTER IT HAS NUDGED THE SURFACE FRONT SOUTHEAST OF THE AREA...WHICH WILL PROVIDE US WITH DRYING AND SOME WELCOME COOLING FOR THE WEEKEND. HIGHS SHOULD RANGE FROM UPPER 70S TO LOWER 80S BOTH DAYS WITH SMALL CHANCE POPS MAINLY IN THE SOUTHEAST. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 140 AM MONDAY... SUB-VFR STRATUS CONTINUES TO DEVELOP/EXPAND WESTWARD. THIS SHOULD BE IN THE REGION THROUGH 13Z-15Z WHEN CIGS LIFT TO MVFR THEN VFR. PATCHY MVFR FOG IS ALSO POSSIBLE THROUGH 12Z-13Z. GENERALLY VFR CONDITIONS ARE EXPECTED TONIGHT THROUGH TUESDAY. OUTLOOK WED-FRI...THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL INCREASE ESPECIALLY LATE IN THE WEEK. IN LATE NIGHT AND MORNING STRATUS OR FOG WILL BE POSSIBLE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...26 NEAR TERM...26 SHORT TERM...KRD LONG TERM...MLM AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
859 PM CDT TUE SEP 8 2015 .UPDATE... ISSUED AT 848 PM CDT TUE SEP 8 2015 AT 830 PM CDT...A COLD FRONTAL BOUNDARY EXTENDED ACROSS SOUTHWEST SASKATCHEWAN. THE FRONT WILL SLOWLY SLIDE SOUTHEAST TONIGHT AND WEDNESDAY WITH ONLY A SLOW SOUTHWARD MOVING COMPONENT AS IT NEARLY ALIGNS WITH THE FLOW ALOFT. LATEST HRRR MODEL RUNS SHOW SOME SCATTERED SHOWERS ACROSS THE NORTHWEST AFTER 09Z TONIGHT AND NORTH CENTRAL AFTER 12Z WEDNESDAY. ADDED MORE SLIGHT CHANCE AREA TO THE NORTHWEST IN CONCERT WITH THE HRRR AFTER 09Z. OTHERWISE CURRENT FORECAST LOOKS GOOD. UPDATE ISSUED AT 553 PM CDT TUE SEP 8 2015 THE NORTHERN PLAINS REMAINS ON THE SOUTHERN EDGE OF A LARGE UPPER LOW ACROSS NORTHERN MANITOBA. THIS HAS MAINTAINED A BREEZY NORTHWEST FLOW ACROSS THE REGION SO FAR THIS AFTERNOON. AS THE EVENING APPROACHES EXPECT WINDS TO DIMINISH AFTER 7 PM AND SKIES TO BECOME MOSTLY CLEAR. UPDATED CURRENT OBSERVATIONS AND SKY CONDITION ONLY. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 239 PM CDT TUE SEP 8 2015 QUIET WEATHER HIGHLIGHTS THE SHORT TERM FORECAST. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE 12 UTC GUIDANCE SUITES. OVERALL...WEAK HIGH PRESSURE ACROSS WESTERN AND CENTRAL NORTH DAKOTA SOUTH OF THE FILLING NORTHERN MANITOBA LOW WILL CONTINUE TO WEAKEN THROUGH THE NIGHT. A WEAK IMPULSE EMBEDDED IN NORTHWEST FLOW ALOFT ON WEDNESDAY MAY SUPPORT ISOLATED RAIN SHOWER DEVELOPMENT DURING THE AFTERNOON. GIVEN WEAK MID LEVEL LAPSE RATES...DID NOT INCLUDE A MENTION OF THUNDER AT THIS TIME. TEMPERATURES WEDNESDAY ARE EXPECTED TO BE SIMILAR TO TODAY WITH 60S NORTH AND 70S SOUTH. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 239 PM CDT TUE SEP 8 2015 NO MAIN CONCERNS IN THE LONG TERM WITH FAIRLY DRY AND QUIET WEATHER EXPECTED. EARLY IN THE LONG TERM THE NORTHWEST FLOW ALOFT WITH A FEW UPPER LEVEL SHORTWAVES...COMBINED WITH A COLD FRONTAL BOUNDARY OVER THE STATE WILL KEEP SMALL CHANCES OF SHOWERS IN THE FORECAST WEDNESDAY NIGHT AND THURSDAY. FAIRLY COOL WITH LOWS IN THE UPPER 30S TO UPPER 40S...AND HIGHS MAINLY IN THE 60S. ANOTHER COOL NIGHT THURSDAY NIGHT AS THE COOL HIGH PRESSURE CENTER SETTLES OVER THE DAKOTAS BY FRIDAY MORNING. LOWS IN THE MID TO UPPER 30S TO LOWER 40S. THEN A WARMING TREND INTO THE WEEKEND AS THE WESTERN RIDGE BUILDS BACK INTO THE WESTERN PLAINS. THE NEXT CHANCE FOR WIDESPREAD SHOWERS SHOULD BE TUESDAY. THE WESTERN RIDGE WILL BECOME MORE ZONAL OVER THE WEEKEND...THEN SOUTHWEST FLOW ALOFT RETURNS BY TUESDAY AS AN UPPER LEVEL TROUGH DIVES SOUTHEAST FROM THE GULF OF ALASKA INTO THE WEST COAST...DEVELOPING A SURFACE LOW IN THE LEE OF THE ROCKIES BY TUESDAY MORNING...BRINGING BETTER CHANCES FOR PRECIPITATION NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 553 PM CDT TUE SEP 8 2015 SURFACE LOW PRESSURE ACROSS NORTHEAST MONTANA AND AN ASSOCIATED WEAK AND MOSTLY DRY COLD FRONT WILL MOVE ACROSS NORTHERN NORTH DAKOTA ON WEDNESDAY. FOR THE 00Z TAF VFR IS EXPECTED. AN INCREASE IN CLOUDS AOA 5 THOUSAND AGL IS EXPECTED NORTH HALF OF THE STATE WEDNESDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...AYD LONG TERM...JV AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
256 PM CDT MON SEP 7 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 256 PM CDT MON SEP 7 2015 RAIN SHOWERS ENDING BY EARLY THIS EVENING CENTRAL HIGHLIGHT THE SHORT TERM FORECAST. WILL CONTINUE TO RELY ON A TIME LAGGED ENSEMBLE OF THE HRRR FOR POPS THE REMAINDER OF THE AFTERNOON...NAMELY ITS 16-18 UTC ITERATIONS...WHICH HAS DONE WELL THROUGHOUT THE DAY. DID MAINTAIN A SLIGHT CHANCE OF THUNDER WITH A FEW...SPORADIC LIGHTNING STRIKES OBSERVED. EXPECT PRECIPITATION CHANCES...FOCUSED PRIMARILY ACROSS NORTH CENTRAL NORTH DAKOTA AND THE UPPER JAMES RIVER VALLEY THE REST OF THE DAY...TO RAPIDLY DECREASE BY 22-23 UTC AS FORCING FROM TWO SHORTWAVES SOUTH OF THE UPPER LOW NEAR LAKE WINNIPEG SHIFTS EAST. FOR TUESDAY...A QUIET...DRY...ALBEIT SLIGHTLY BELOW NORMAL TEMPERATURE-WISE DAY IS FORECAST SOUTH OF THE NOW FILLING AFOREMENTIONED LOW. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE 12 UTC GUIDANCE SUITES FOR ALL FIELDS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 256 PM CDT MON SEP 7 2015 NORTHWEST FLOW ALOFT THROUGH FRIDAY WITH FLOW ROTATING AROUND THE HUDSON BAY LOW AND RIDGE OVER THE EASTERN PACIFIC AND WEST COAST. SHORTWAVE ENERGY MOVING THROUGH THIS FLOW APPROACHES NORTHERN NORTH DAKOTA LATE TUESDAY NIGHT/WEDNESDAY MORNING...WITH AN ATTENDANT WEAK SURFACE LOW AND COLD FRONT. MORE SHORTWAVE ENERGY IMPULSES MOVE SOUTHEAST ACROSS THE STATE WEDNESDAY AFTERNOON WITH A COLD FRONT MOVING SOUTH ACROSS THE STATE. THIS WILL RESULT IN SLIGHT CHANCES OF SHOWERS...MAINLY NORTHWEST AND CENTRAL...ON WEDNESDAY. SEASONABLE TEMPERATURES WEDNESDAY WITH HIGHS FROM THE UPPER 60S NORTH TO UPPER 70S SOUTH. ANOTHER SERIES OF SHORTWAVES MOVES ACROSS THE STATE WEDNESDAY NIGHT WITH A SECONDARY PUSH OF COLD AIR IN THE FORM OF A BACKDOOR COLD FRONT MOVING SOUTHWEST ACROSS THE STATE. SLIGHT CHANCES OF SHOWERS WILL REMAIN IN THE FORECAST NORTHWEST AND CENTRAL WEDNESDAY NIGHT...WITH MAINLY DRY BUT COOL CONDITIONS EXPECTED THURSDAY. LOOK FOR HIGHS IN THE 60S TO LOWER 70S. THE UPPER LEVEL WESTERN RIDGE BUILDS BACK INTO THE REGION FOR THE WEEKEND...WITH DRY CONDITIONS AND SLIGHTLY ABOVE AVERAGE TEMPERATURES. HIGHS IN THE 70S TO LOWER 80S. THE MODELS BRING AN UPPER LEVEL SHORTWAVE MOVING THROUGH THE FLOW...FLATTENING THE RIDGE...BRINGING A CHANCE OF SHOWERS AND COOLER WEATHER FOR MONDAY WITH HIGHS MAINLY IN THE 60S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 256 PM CDT MON SEP 7 2015 VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL CLOUD COVER WILL REMAIN ACROSS MUCH OF CENTRAL AND EASTERN NORTH DAKOTA THROUGH THE AFTERNOON. LIGHT SHOWERS EXPECTED TO IMPACT KJMS THROUGH THE AFTERNOON...AND POSSIBLY KMOT BRIEFLY. PATCHY FOG MAY BE POSSIBLE AT KBIS/KJMS TONIGHT. HOWEVER...GIVEN HIGH UNCERTAINTY...LEFT IT OUT OF THE TAFS FOR NOW. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...AYD LONG TERM...JV AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1238 PM CDT MON SEP 7 2015 .UPDATE... ISSUED AT 1238 PM CDT MON SEP 7 2015 TRICKY TEMP FORECAST AS CLOUDS AND PRECIP MOVING INTO THE SOUTHWESETERN COUNTIES HAVE KEPT TEMPS COOLER BUT THE NORTHWEST HAS QUICKLY GONE UP INTO THE 70S. ADJUSTED ACCORDINGLY...LOWERING HIGHS A FEW DEGREES IN THE SOUTHWEST AND BUMPING THEM UP IN THE NORTHWEST. WEB CAMS SHOW THE RADAR RETURNS MOVING IN ARE TAKING A WHILE TO REACH THE GROUND...BUT WESTERN RANSOM AND SARGENT COUNTIES ARE FINALLY GETTING SOME RAIN. SCATTERED RAIN SHOWERS WILL CONTINUE TO BE A THREAT THROUGH THIS AFTERNOON...SO BUMPED UP POPS A BIT. UPDATE ISSUED AT 934 AM CDT MON SEP 7 2015 TWEAKED POPS TO INCLUDE THE SHOWERS MOVING INTO THE VALLEY CITY AREA. NOT MUCH IS REACHING THE GROUND...BUT RETURNS ARE STRONG ENOUGH AS A SHORTWAVE MOVES UP FROM SOUTH DAKOTA TO INCLUDE A SMALL CHANCE FOR RAIN THROUGHOUT THIS AFTERNOON. OVERALL KEPT THE TREND OF INCREASING CLOUDS AND HIGHS TOPPING OUT IN THE 60S TO MID 70S. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON SEP 7 2015 THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON. GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL. ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE 70S. DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA SHIFTS EAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON SEP 7 2015 WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE FORECAST ACCORDINGLY FOR POPS AND TEMPS. THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO PREFER THE ECMWF. HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1238 PM CDT MON SEP 7 2015 A LARGE BATCH OF MID LEVEL CLOUDS WILL MOVE THRU THE AREA THIS AFTERNOON AND EVENING...AND MAY ALSO DROP A FEW LIGHT SHOWERS. ECHOES HAVE BEEN DRYING UP AS THEY HAVE MOVED EAST-NE SO AT THIS POINT WILL ONLY MENTION VCSH AT KFAR/KGFK. OTHERWISE WINDS LOOK TO REMAIN FAIRLY LOW THROUGHOUT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...TG LONG TERM...TG/HOPPES AVIATION...GODON
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1211 PM CDT MON SEP 7 2015 .UPDATE... ISSUED AT 1205 PM CDT MON SEP 7 2015 INCREASED CLOUD COVER ACROSS MUCH OF CENTRAL NORTH DAKOTA FOR THE REMAINDER OF THE DAY AHEAD OF TWO SHORTWAVES EMBEDDED IN THE CYCLONIC FLOW SOUTH OF THE UPPER LOW NORTH OF LAKE WINNIPEG AS OF 17 UTC. AS A RESULT...DID DECREASE HIGHS INTO THE 60S FOR AREAS TO REMAIN UNDER OVERCAST SKIES. POPS BLENDED TO A TIME LAGGED ENSEMBLE OF THE 13-15 UTC HRRR ITERATIONS WHICH CONTINUES TO PERFORM WELL WITH THIS PRECIPITATION EVENT. UPDATE ISSUED AT 843 AM CDT MON SEP 7 2015 QUICK UPDATE TO BLEND RADAR TRENDS TO THE TIME LAGGED ENSEMBLE OF THE 10-12 UTC HRRR ITERATIONS...AND ADD AN ISOLATED MENTION OF THUNDERSTORMS SOUTH CENTRAL THIS MORNING AND THROUGH THE AFTERNOON WITH A FEW LIGHTNING STRIKES OBSERVED THUS FAR. UPDATE ISSUED AT 623 AM CDT MON SEP 7 2015 ONLY CHANGE FOR MORNING UPDATE WAS TO TRIM POPS BACK A BIT IN THE EARLY MORNING AS EXPECT THE ONSET OF SHOWERS WILL BE DELAYED A LITTLE. OTHERWISE...GOING FORECAST WAS IN GOOD SHAPE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 310 AM CDT MON SEP 7 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL CHANCES FOR SHOWERS TODAY SOUTHWEST AND CENTRAL...AND COOL/BELOW NORMAL TEMPERATURES BOTH TODAY AND TUESDAY. CURRENTLY...UPPER LEVEL LOW PRESSURE SPINNING OVER SOUTHERN SASKATCHEWAN WITH A 100KT UPPER LEVEL JET ROUNDING THE BASE OF THE LOW INTO THE WESTERN DAKOTAS. STRONG FLOW ALOFT RESULTING IN MID LEVEL MOISTURE ADVECTION WITH INCREASING MID AND HIGH LEVEL CLOUDINESS. DESPITE CLOUDS SOUTHWEST VERY DRY DEWPOINTS IN THE 30S RESULTING IN TEMPERATURES IN THE LOW 40S AND EVEN A FEW UPPER 30S. THE UPPER JET STREAK IS INDUCING A SUBTLE SURFACE TROUGH OVER WESTERN SOUTH DAKOTA EARLY THIS MORNING...AND WILL EVENTUALLY DEVELOP INTO SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA LATER THIS MORNING AND AFTERNOON. COUPLED WITH FORCING ALOFT EXPECT SHOWERS TO DEVELOP NEAR THE TROUGH AXIS AS IT SLOWLY MOVES EAST TODAY. WHILE WE WILL REALIZE SOME MOISTURE RETURNING BACK INTO THE AREA INSTABILITY IS VERY MINIMAL SO REMOVED ALL MENTION OF THUNDER FROM THE FORECAST. FORCING ALOFT MOVES OFF TO OUR EAST AFTER 00Z SO MAINTAINED A DRY EVENING AND OVERNIGHT PERIOD. UPPER LOW CONTINUES EAST ACROSS SOUTH CENTRAL CANADA...ROTATING ANOTHER EMBEDDED WAVE AND ASSOCIATED JET STREAK ACROSS THE STATE LATE MONDAY NIGHT INTO TUESDAY. AT THIS TIME SFC FORCING LOOKS NIL WITH SFC HIGH PRESSURE MOVING EAST ACROSS THE REGION SO KEPT THE TUESDAY MORNING AND AFTERNOON PERIOD DRY FOR NOW. HIGH TEMPERATURES BOTH TODAY AND TUESDAY VERY COMFORTABLE IN THE UPPER 60S TO MID 70S. TEMPERATURES TONIGHT SHOULD BE SIMILAR TO CURRENT CONDITIONS...40S WITH A FEW AREAS DROPPING INTO THE UPPER 30S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 248 AM CDT MON SEP 7 2015 BROAD SHORT WAVE ROTATING AROUND HUDSON BAY LOW PASSES OVER THE AREA WEDNESDAY AND WEDNESDAY NIGHT...POSSIBLY BRINGING SOME PRECIPITATION TO OUR AREA. FOR THE REST OF THE WORK WEEK...NORTHWESTERLY FLOW WITH RIDGING OVER THE WESTERN CONUS WILL BRING QUIET WEATHER AND COMFORTABLE TEMPERATURES TO THE AREA. WARMER CONDITIONS RETURN FOR SATURDAY AS RIDGE AXIS PASSES OVER. BEHIND THE RIDGE...A FEW THUNDERSTORMS MAY DEVELOP INTO SATURDAY NIGHT. AVERAGE TEMPERATURES RETURN FOR SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1205 PM CDT MON SEP 7 2015 VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL CLOUD COVER WILL REMAIN ACROSS MUCH OF CENTRAL AND EASTERN NORTH DAKOTA THROUGH THE AFTERNOON. LIGHT SHOWERS EXPECTED TO IMPACTKBIS AND KJMS THROUGH THE AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...NH LONG TERM...JJS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
934 AM CDT MON SEP 7 2015 .UPDATE... ISSUED AT 934 AM CDT MON SEP 7 2015 TWEAKED POPS TO INCLUDE THE SHOWERS MOVING INTO THE VALLEY CITY AREA. NOT MUCH IS REACHING THE GROUND...BUT RETURNS ARE STRONG ENOUGH AS A SHORTWAVE MOVES UP FROM SOUTH DAKOTA TO INCLUDE A SMALL CHANCE FOR RAIN THROUGHOUT THIS AFTERNOON. OVERALL KEPT THE TREND OF INCREASING CLOUDS AND HIGHS TOPPING OUT IN THE 60S TO MID 70S. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON SEP 7 2015 THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON. GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL. ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE 70S. DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA SHIFTS EAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON SEP 7 2015 WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE FORECAST ACCORDINGLY FOR POPS AND TEMPS. THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO PREFER THE ECMWF. HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 644 AM CDT MON SEP 7 2015 VFR THROUGH THE PERIOD. CLEAR SKY THIS MORNING WILL GIVE WAY TO INCREASING MID-LEVEL CLOUDS...THEN LIKELY CLEAR AGAIN BY TUESDAY MORNING. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...TG LONG TERM...TG/HOPPES AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
846 AM CDT MON SEP 7 2015 .UPDATE... ISSUED AT 843 AM CDT MON SEP 7 2015 QUICK UPDATE TO BLEND RADAR TRENDS TO THE TIME LAGGED ENSEMBLE OF THE 10-12 UTC HRRR ITERATIONS...AND ADD AN ISOLATED MENTION OF THUNDERSTORMS SOUTH CENTRAL THIS MORNING AND THROUGH THE AFTERNOON WITH A FEW LIGHTNING STRIKES OBSERVED THUS FAR. UPDATE ISSUED AT 623 AM CDT MON SEP 7 2015 ONLY CHANGE FOR MORNING UPDATE WAS TO TRIM POPS BACK A BIT IN THE EARLY MORNING AS EXPECT THE ONSET OF SHOWERS WILL BE DELAYED A LITTLE. OTHERWISE...GOING FORECAST WAS IN GOOD SHAPE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 310 AM CDT MON SEP 7 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL CHANCES FOR SHOWERS TODAY SOUTHWEST AND CENTRAL...AND COOL/BELOW NORMAL TEMPERATURES BOTH TODAY AND TUESDAY. CURRENTLY...UPPER LEVEL LOW PRESSURE SPINNING OVER SOUTHERN SASKATCHEWAN WITH A 100KT UPPER LEVEL JET ROUNDING THE BASE OF THE LOW INTO THE WESTERN DAKOTAS. STRONG FLOW ALOFT RESULTING IN MID LEVEL MOISTURE ADVECTION WITH INCREASING MID AND HIGH LEVEL CLOUDINESS. DESPITE CLOUDS SOUTHWEST VERY DRY DEWPOINTS IN THE 30S RESULTING IN TEMPERATURES IN THE LOW 40S AND EVEN A FEW UPPER 30S. THE UPPER JET STREAK IS INDUCING A SUBTLE SURFACE TROUGH OVER WESTERN SOUTH DAKOTA EARLY THIS MORNING...AND WILL EVENTUALLY DEVELOP INTO SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA LATER THIS MORNING AND AFTERNOON. COUPLED WITH FORCING ALOFT EXPECT SHOWERS TO DEVELOP NEAR THE TROUGH AXIS AS IT SLOWLY MOVES EAST TODAY. WHILE WE WILL REALIZE SOME MOISTURE RETURNING BACK INTO THE AREA INSTABILITY IS VERY MINIMAL SO REMOVED ALL MENTION OF THUNDER FROM THE FORECAST. FORCING ALOFT MOVES OFF TO OUR EAST AFTER 00Z SO MAINTAINED A DRY EVENING AND OVERNIGHT PERIOD. UPPER LOW CONTINUES EAST ACROSS SOUTH CENTRAL CANADA...ROTATING ANOTHER EMBEDDED WAVE AND ASSOCIATED JET STREAK ACROSS THE STATE LATE MONDAY NIGHT INTO TUESDAY. AT THIS TIME SFC FORCING LOOKS NIL WITH SFC HIGH PRESSURE MOVING EAST ACROSS THE REGION SO KEPT THE TUESDAY MORNING AND AFTERNOON PERIOD DRY FOR NOW. HIGH TEMPERATURES BOTH TODAY AND TUESDAY VERY COMFORTABLE IN THE UPPER 60S TO MID 70S. TEMPERATURES TONIGHT SHOULD BE SIMILAR TO CURRENT CONDITIONS...40S WITH A FEW AREAS DROPPING INTO THE UPPER 30S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 248 AM CDT MON SEP 7 2015 BROAD SHORT WAVE ROTATING AROUND HUDSON BAY LOW PASSES OVER THE AREA WEDNESDAY AND WEDNESDAY NIGHT...POSSIBLY BRINGING SOME PRECIPITATION TO OUR AREA. FOR THE REST OF THE WORK WEEK...NORTHWESTERLY FLOW WITH RIDGING OVER THE WESTERN CONUS WILL BRING QUIET WEATHER AND COMFORTABLE TEMPERATURES TO THE AREA. WARMER CONDITIONS RETURN FOR SATURDAY AS RIDGE AXIS PASSES OVER. BEHIND THE RIDGE...A FEW THUNDERSTORMS MAY DEVELOP INTO SATURDAY NIGHT. AVERAGE TEMPERATURES RETURN FOR SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 843 AM CDT MON SEP 7 2015 VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. INCREASING MID AND HIGH LEVEL CLOUDS THROUGH MONDAY MORNING. LIGHT SHOWERS POSSIBLE MONDAY MORNING/AFTERNOON FOR KBIS-KJMS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...NH LONG TERM...JJS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
644 AM CDT MON SEP 7 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON SEP 7 2015 THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON. GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL. ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE 70S. DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA SHIFTS EAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON SEP 7 2015 WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE FORECAST ACCORDINGLY FOR POPS AND TEMPS. THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO PREFER THE ECMWF. HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 644 AM CDT MON SEP 7 2015 VFR THROUGH THE PERIOD. CLEAR SKY THIS MORNING WILL GIVE WAY TO INCREASING MID-LEVEL CLOUDS...THEN LIKELY CLEAR AGAIN BY TUESDAY MORNING. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...TG LONG TERM...TG/HOPPES AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
348 AM CDT MON SEP 7 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON SEP 7 2015 THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON. GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL. ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE 70S. DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA SHIFTS EAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON SEP 7 2015 WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE FORECAST ACCORDINGLY FOR POPS AND TEMPS. THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO PREFER THE ECMWF. HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1145 PM CDT SUN SEP 6 2015 VFR THRU THE PERIOD. GENERALLY CLEAR WITH LIGHT WINDS OVERNIGHT. COULD BE PATCHY RADIATIONAL FOG NR SUNRISE BEMIDJI AREA...BUT CONFIDENCE IS QUITE LOW AND ANY FOG WILL BE SPOTTY SO WILL KEEP VSBY P6SM. OTHERWISE INCREASE IN HIGH AND MID CLOUDS THRU THE DAY MONDAY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...TG LONG TERM...TG/HOPPES AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1148 PM CDT SUN SEP 6 2015 .UPDATE... ISSUED AT 1145 PM CDT SUN SEP 6 2015 SKIES CLEAR AND WINDS BECOMING LIGHT. SOME THIN CIRRUS ENTERING WRN ND AND WILL SPREAD NORTHEAST OVERNIGHT. LATEST HRRR MODEL RUNS DONT INDICATE ANY FOG...SO WILL NOT MENTION. WILL STILL NEED TO KEEP AN EYE ON IT THOUGH IN THE FAR EASTERN FCST AREA. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 350 PM CDT SUN SEP 6 2015 REST OF THE AFTERNOON AND EVENING...A WEAK FRONTAL BOUNDARY DRAPED ALONG THE BDE-BJI-PKD-ETH LINE WILL SLOWLY SHIFT EASTWARD AND PROVIDE SOME FOCUS FOR STRONG SHOWER AND THUNDERSTORM DEVELOPMENT. BEHIND THIS BOUNDARY IN NORTHWEST MINNESOTA... ISOLATED ELEVATED CONVECTION IS POSSIBLE THROUGH THE LATE AFTERNOON PERIOD. BY 00Z THUNDERSTORM ACTIVITY WILL HAVE MOVED INTO CENTRAL AND EASTERN PORTIONS OF MINNESOTA... WITH A SOMEHWAT DRIER WESTERLY FLOW PERSISTING INTO THE OVERNIGHT HOURS. LABOR DAY...SOME PATCHY GROUND FOG IS POSSIBLE OVER THE MINNESOTA LAKES COUNTRY IN THE EARLY MORNING. OTHERWISE...EXPECT GENERALLY FAIR SKIES INTO MIDDAY AND SEASONABLY MILD CONDITIONS THROUGHOUT THE DAY. A LIGHT SOUTHERLY BREEZE WILL TURN LIGHT AND VARIABLE THROUGH THE AFTERNOON AS SURFACE HIGH PRESSURE MOVES INTO CENTRAL MINNESOTA. AREAS OF FAIRLY HIGH BASED AND SHALLOW CUMULUS CLOUDS WILL LIKELY DEVELOP IN THE AFTERNOON... AND AN ISOLATED SPRINKLE IS POSSIBLE... BUT MEASURABLE PRECIPITATION IS NOT EXPECTED. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 350 PM CDT SUN SEP 6 2015 TUESDAY THROUGH WEDNESDAY...A FAIRLY BROAD AND SHALLOW H5 TROF SETS UP ACROSS THE NORTHERN PLAINS FOR THE EARLY WEEK PERIOD WITH WEST-NORTHWESTERLY FLOW ALOFT OVER THE AREA. MODELS ARE FAIRLY CONSISTENT IN MAINTAINING AN OVERALL DRY FLOW OVER MOST OF THE DAK-MINN AREA THROUGH TUESDAY... WITH SOME MOISTURE AND ENERGY DROPPING INTO THE AREA ON WEDNESDAY. WEDNESDAY NIGHT THROUGH SUNDAY...FLOW TRANSITIONS FROM TROUGHING AND NORTHWESTERLY FLOW ALOFT TO MORE ZONAL AS A TROUGH DIGS INTO THE UPPER MIDWEST AND THEN MOVES EAST. SOME SHOWERS WILL LINGER INTO WEDNESDAY NIGHT AND THURSDAY AS A REINFORCING SURGE OF COOL AIR COMES DOWN...BUT THE END OF THE WEEK SHOULD BE DRY. LOWERED THE BLENDED POPS A BIT TO REMOVE MENTION OF PRECIP THURSDAY NIGHT AND FRIDAY AS WE SHOULD BE FIRMLY UNDER HIGH PRESSURE BY THEN. ANOTHER APPROACHING FRONT ON SUNDAY COULD BRING A CHANCE FOR PRECIP...BUT WITH A LOT OF VARIATION ON TIMING KEPT CHANCES LOW. TEMPS WILL BE COOLER THAN AVERAGE AT THE START OF THE PERIOD BUT WILL WARM UP INTO NEXT WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1145 PM CDT SUN SEP 6 2015 VFR THRU THE PERIOD. GENERALLY CLEAR WITH LIGHT WINDS OVERNIGHT. COULD BE PATCHY RADITIONAL FOG NR SUNRISE BEMIDJI AREA...BUT CONFIDENCE IS QUITE LOW AND ANY FOG WILL BE SPOTTY SO WILL KEEP VSBY P6SM. OTHERWISE INCREASE IN HIGH AND MID CLOUDS THRU THE DAY MONDAY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...RIDDLE SHORT TERM...GUST LONG TERM...GUST/JR AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS NORMAN OK
1218 PM CDT MON SEP 7 2015 .AVIATION... 18Z TAFS... VFR CONDITIONS EXPECTED THIS TAF PERIOD WITH SOME MID AND HIGH CLOUDS. A FEW SHOWERS/STORMS MAY AFFECT PARTS OF NW OK TUESDAY MORNING. && .PREV DISCUSSION... /ISSUED 614 AM CDT MON SEP 7 2015/ DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. AVIATION... VFR CONDITIONS ARE EXPECTED TO CONTINUE. MBS PREV DISCUSSION... /ISSUED 347 AM CDT MON SEP 7 2015/ DISCUSSION... HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL AS COOLER WEATHER ARE THE NEXT CONCERNS. THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING. THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED DOWNPOURS. THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY LOCATIONS. LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY CONDITIONS WILL PERSIST. TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL. LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES APPEAR TO BE NEAR AND EAST OF I-35. HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT. WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY REMAIN FAIRLY MUGGY. WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 98 74 96 69 / 10 10 30 60 HOBART OK 103 75 99 69 / 0 10 30 50 WICHITA FALLS TX 99 73 100 72 / 10 0 10 60 GAGE OK 101 76 94 64 / 10 10 40 30 PONCA CITY OK 98 77 91 67 / 10 10 50 70 DURANT OK 97 74 97 72 / 20 20 20 70 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 30/25/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
614 AM CDT MON SEP 7 2015 .DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. && .AVIATION... VFR CONDITIONS ARE EXPECTED TO CONTINUE. MBS && .PREV DISCUSSION... /ISSUED 347 AM CDT MON SEP 7 2015/ DISCUSSION... HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL AS COOLER WEATHER ARE THE NEXT CONCERNS. THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING. THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED DOWNPOURS. THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY LOCATIONS. LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY CONDITIONS WILL PERSIST. TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL. LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES APPEAR TO BE NEAR AND EAST OF I-35. HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT. WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY REMAIN FAIRLY MUGGY. WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 99 74 96 69 / 10 10 30 60 HOBART OK 103 75 101 69 / 0 10 30 50 WICHITA FALLS TX 100 73 100 72 / 10 0 10 60 GAGE OK 101 76 94 64 / 10 10 40 30 PONCA CITY OK 99 77 91 67 / 10 10 50 70 DURANT OK 97 74 97 72 / 20 20 20 70 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 17
AREA FORECAST DISCUSSION
NWS NORMAN OK
347 AM CDT MON SEP 7 2015 .DISCUSSION... HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL AS COOLER WEATHER ARE THE NEXT CONCERNS. THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING. THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED DOWNPOURS. THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY LOCATIONS. LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY CONDITIONS WILL PERSIST. TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL. LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES APPEAR TO BE NEAR AND EAST OF I-35. HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT. WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY REMAIN FAIRLY MUGGY. WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 99 74 96 69 / 10 10 30 60 HOBART OK 103 75 101 69 / 0 10 30 50 WICHITA FALLS TX 100 73 100 72 / 10 0 10 60 GAGE OK 101 76 94 64 / 10 10 40 30 PONCA CITY OK 99 77 91 67 / 10 10 50 70 DURANT OK 97 74 97 72 / 20 20 20 70 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 17
AREA FORECAST DISCUSSION
NWS TULSA OK
1135 PM CDT SUN SEP 6 2015 .DISCUSSION... The 06z TAF discussion is included below... && .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. The theme of the 00z forecast remains in tact. Still some potential as suggested in the latest runs of the HRRR that some high based tsra is possible toward 12z across NE OK. Some light mvfr fog is possible near sunrise at KBVO, KFYV, and KROG. Afternoon isolated storms are expected to develop in the terrain again over in SE OK and NW AR...with KFSM standing the greatest risk of being affected. For both convective scenarios...confidence and coverage were not great enough to go with TEMPO...so will instead go the conservative VCTS route. Lacy && .PREV DISCUSSION... /ISSUED 738 PM CDT SUN SEP 6 2015/ DISCUSSION... Sent out an early update this evening as area 88Ds indicate afternoon convection has pretty much all dissipated at this time, so we removed mention of thunderstorms this evening. As previous discussion indicated, we have also added slight chance POPs for nern OK and far nwrn AR late tonight/Monday morning. Short-term models hint at some high-based convection developing into our CWA after 09z as mid-levels moisten/destabilize. Will likely result in a bit more cloudiness Monday morning but not enough to impact expected max temperatures later in the day. Updated products already issued... PREV DISCUSSION... /ISSUED 705 PM CDT SUN SEP 6 2015/ DISCUSSION... The 00z taf discussion is included below... AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. Ridging remains in place aloft...which will maintain VFR conditions for the most part thru this forecast period. However...there are a few possible exceptions or things to note. The latest data indicates mid level moistening that could produce some high based thunderstorms around sunrise and into the morning hours across NE OK. In addition...some light MVFR fog is possible over in NW AR around sunrise as well. By tomorrow afternoon...daytime heating will produce isolated thunderstorms over in the terrain of SE OK/W AR. KFSM stands the best chance of being affected. With both of the convective scenarios discussed...confidence and coverage would suggest staying conservative...so will use VCTS mention instead of prob30 or TEMPO for now. Lacy && .PRELIMINARY POINT TEMPS/POPS... TUL 75 96 76 93 / 20 20 10 20 FSM 75 96 74 93 / 10 20 10 20 MLC 75 96 75 94 / 10 10 10 20 BVO 70 95 71 91 / 20 20 10 40 FYV 69 90 71 89 / 10 10 10 30 BYV 69 91 70 89 / 10 20 10 30 MKO 74 95 74 93 / 10 10 10 20 MIO 74 94 75 90 / 20 20 10 40 F10 75 96 75 94 / 10 10 10 20 HHW 75 97 74 95 / 10 20 10 20 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1134 PM EDT TUE SEP 8 2015 .SYNOPSIS... HIGH PRESSURE THAT BROUGHT US THIS RECENT STRING OF DRY AND VERY WARM DAYS WILL DRIFT OFF THE EAST COAST. A COLD FRONT WILL MOVE SLOWLY EAST ACROSS THE REGION WEDNESDAY AFTERNOON AND NIGHT. A WAVE OF LOW PRESSURE WILL FORM ALONG THIS FRONT AND BRING A SHOWERY AND MUCH COOLER DAY FOR THURSDAY. MAINLY DRY AND SEASONABLY COOL CONDITIONS WILL FOLLOW FOR LATER THURSDAY NIGHT THROUGH FRIDAY. A DEEP TROUGH WILL FORM OVER THE OHIO AND TENNESSEE VALLEYS SATURDAY...THEN MOVE SLOWLY TO THE NORTHEAST SUNDAY AND MONDAY BRINGING THE POTENTIAL FOR LOCALLY HEAVY RAIN. && .NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/... 10 PM UPDATE... TEMPS COOLING OFF QUICKLY - SOME MESO OBS AROUND STATE COLLEGE ARE 20 DEGREES COOLER THAN THE MAXES. 95F WAS THE HOTTEST DAY IN TWO YEARS AT HARRISBURG...BUT NO RECORD MAX FOR THEM SINCE THE RECORD FOR THE DAY IS 99F. STILL A COUPLE OF VERY LIGHT SHOWERS ALONG THE HIGHER RIDGELINES OF THE LAURELS AND ALLEGHENIES. HOWEVER...WITH 50-SOMETHING DEWPOINTS AND CLOUD CEILINGS AOA 8KFT IN THAT AREA...CAN/T IMAGINE MUCH IS REACHING THE GROUND. ONE ECHO JUST PASSED RIGHT OVER KFIG AND DID MAKE A TRACE /LESS THAN ONE HUNDRETH OF AN INCH/ THERE. EXPECT THAT SOME OF THESE VERY LIGHT AND QUICK-MOVING SHOWERS WILL CONTINUE THROUGH MIDNIGHT OR A FEW HOURS INTO THE NEW DAY. HOWEVER...A 20 POP COULD EVEN BE OVERDONE AS THE LIKELIHOOD OF MEASURING IS EXTREMELY LOW AND COVERAGE VERY VERY SPARSE. 8 PM UPDATE... CLOUDS NOT GOING AWAY ALONG THE ALLEGHENY FRONT AND ARE EVEN DEVELOPING/GROWING SLIGHTLY. SPECKLES OF REFLECTIVITY ARE STARTING TO SHOW UP ON RADAR AS WELL...EVEN NEAR KMDT. NAM AND HRRR HAS THIS - PERHAPS OVER DOING IT - GENERATING SOME QPF OVER MOST OF THOSE HIGHER ELEVATIONS IN THE ALLEGHENIES OVER THE NEXT 3-4HRS. THE LOW/MID LEVEL FLOW IS INCREASING SLIGHTLY AND COULD BE RUNNING INTO LIGHTER FLOW OUT OF THE SOUTHWEST. THE WINDS THEN BECOME MORE- ALIGNED IN THE LOWEST 10KFT LATER TONIGHT. LOWEST CLOUD DECK IS ABOUT 8KFT...SO WILL COUNT ON ANY RAIN FALLING FROM THEM TO MOSTLY DRY UP BEFORE IT GETS TO THE GROUND. STILL...A VERY LIGHT SHOWER IS POSSIBLE THERE FOR THE NEXT FEW HOURS. FROM PREV... SOME OF THE HIGHEST TERRAIN ACROSS THE WEST COULD SEE THE SW WIND STAY UP AT AROUND 5-8 KTS TONIGHT AS THE LLVL P-GRADIENT TIGHTENS A BIT. LOW TEMPS TONIGHT WILL VARY FROM THE LOWER 60S ACROSS THE NRN AND WRN HIGH TERRAIN...TO THE MID 60S IN THE CENTRAL MTNS...AND AROUND 70F IN THE METRO AREAS OF THE LOWER SUSQ VALLEY. && .SHORT TERM /8 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... APPROACHING SHORTWAVE AND ASSOC SFC COLD FRONT WILL BRING A CHANCE OF MAINLY AFTERNOON AND EVENING SHRA/TSRA WEDNESDAY. HIGHEST /LIKELY/ POPS ARE PAINTED ACROSS THE NW MTNS CLOSEST TO APPROACHING COLD FRONT. ALL SHORT RANGE MDLS INDICATE THERE WILL BE A MINIMUM IN SHOWER ACTIVITY ACROSS THE CENTRAL MTNS IN CONJUNCTION WITH LINGERING RIBBON OF LOWER PWATS. PARTLY-MOSTLY CLOUDY SKIES AND SCT PM CONVECTION MAY HOLD TEMPS DOWN A BIT FROM RECENT DAYS. HOWEVER...THE AIR MASS REMAINS VERY WARM WITH MDL 8H TEMPS AOA 18C. EXPECT TEMPS TO TOP OUT WELL INTO THE 80S AGAIN...WITH 90F STILL POSSIBLE ACROSS THE SUSQ VALLEY. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... LITTLE CHANGE IN MEDIUM RANGE MODELS AND EFS TODAY AS TRANSITION FROM HOT AND DRY SUMMERTIME CONDITIONS PERSISTS LATER THIS WEEK INTO THIS WEEKEND. WHILE LEADING SHORTWAVE NUDGES AND DISPLACES RIDGE SLIGHTLY AT MIDWEEK...TRAILING SLOW- MOVING COLD FRONT PASSES THROUGH PENNSYLVANIA LATE WEDNESDAY NIGHT INTO THURSDAY WHILE DEEP UPPER TROF SLOWLY PROPOGATES THROUGH THE GREAT LAKES AND THE OHIO VALLEY THURSDAY AND FRIDAY. BENEFICIAL RAINFALL EXPECTED FROM THIS SLOW MOVING SYSTEM...AND SHOWERS WILL LIKELY LINGER OVER SOUTHEAST PA ON THURSDAY BEFORE EXITING THE EASTERN SEABOARD THU NIGHT. AFTER A FAIR DAY FRIDAY...MOISTURE SHOULD INCREASE AGAIN THROUGHOUT THE DAY SATURDAY AS DEEP UPPER TROF ARRIVES FROM THE OHIO VALLEY. MODELS AND EFS CREATE OHIO VALLEY CUTOFF LOW WHICH WILL KEEP SHOWERY CONDITIONS OVER THE REGION FOR THE REST OF THE WEEKEND BEFORE DRYING ARRIVES TO START THE WEEK...AND HIGH PRESSURE BUILDS OVER THE MIDDLE APPALACHIANS TO THE MID ATLANTIC COAST MON-TUE. THIS WILL ALLOW TEMPS TO REBOUND AFTER A BRIEF DIP SAT-SUN ASSOCIATED WITH THE AFOREMENTIONED CUTOFF. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... 03Z TAFS SENT. EARLIER DISCUSSION BELOW. STILL A FEW LOW...MID...AND HIGH CLDS AROUND. MAINLY LOOKING AT VFR CONDITIONS TONIGHT INTO WED. SOME FOG POSSIBLE AT BFD FOR AN HOUR OR SO LATE TONIGHT. LIKEWISE SOME POSSIBLE AT LNS. EXPECT IPT TO HAVE SOME FOG LATE...ALONG WITH A LOW CIG. ALL THIS BASED ON A MIX OF GUIDANCE AND WHAT HAPPEN LAST NIGHT. LIMITING FACTOR TONIGHT WILL BE A LITTLE MORE OF A SW BREEZE...AS THE GRADIENT PICKS UP. THIS BEING THE RESULT OF THE LOW TRACKING NE ACROSS THE CENTRAL GREAT LAKES. ALSO DEWPOINTS THIS AFTERNOON HAVE BEEN ON THE DECREASE. THERE COULD BE A SHOWER OR TWO AT BFD ON WED...BUT HARD TO SEE MUCH GOING ON...THUS JUST WENT WITH VCSH AT BFD. 00Z TAFS SENT. A COLD FRONT WILL DRIFT SLOWLY EAST FROM THE GREAT LAKES AND CROSS THE REGION LATE WEDNESDAY AFTERNOON AND WED NIGHT. MAIN CHC FOR SHOWERS WILL BE ACROSS THE WRN MTNS OF PA...COINCIDING WITH PEAK HEATING CLOSE TO THE TIME OF THE CFROPA. CHC FOR SHOWERS WILL DIMINISH ACROSS THE ERN HALF OF PA. OUTLOOK... THU...MORE NUMEROUS SHRA/TSRA EXPECTED. BRIEF IFR CIGS AND VSBYS POSSIBLE. FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR. SAT...SCATTERED SHRA/TSRA. SUN...SCATTERED SHOWERS...MAINLY EASTERN AREAS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...DANGELO/LAMBERT SHORT TERM...FITZGERALD/LAMBERT LONG TERM...DEVOIR/FITZGERALD/CERU AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
826 PM EDT TUE SEP 8 2015 .SYNOPSIS... HIGH PRESSURE THAT BROUGHT US THIS RECENT STRING OF DRY AND VERY WARM DAYS WILL DRIFT OFF THE EAST COAST. A COLD FRONT WILL MOVE SLOWLY EAST ACROSS THE REGION WEDNESDAY AFTERNOON AND NIGHT. A WAVE OF LOW PRESSURE WILL FORM ALONG THIS FRONT AND BRING A SHOWERY AND MUCH COOLER DAY FOR THURSDAY. MAINLY DRY AND SEASONABLY COOL CONDITIONS WILL FOLLOW FOR LATER THURSDAY NIGHT THROUGH FRIDAY. A DEEP TROUGH WILL FORM OVER THE OHIO AND TENNESSEE VALLEYS SATURDAY...THEN MOVE SLOWLY TO THE NORTHEAST SUNDAY AND MONDAY BRINGING THE POTENTIAL FOR LOCALLY HEAVY RAIN. && .NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/... 8 PM UPDATE... CLOUDS NOT GOING AWAY ALONG THE ALLEGHENY FRONT AND ARE EVEN DEVELOPING/GROWING SLIGHTLY. SPECKLES OF REFLECTIVITY ARE STARTING TO SHOW UP ON RADAR AS WELL...EVEN NEAR KMDT. NAM AND HRRR HAS THIS - PERHAPS OVER DOING IT - GENERATING SOME QPF OVER MOST OF THOSE HIGHER ELEVATIONS IN THE ALLEGHENIES OVER THE NEXT 3-4HRS. THE LOW/MID LEVEL FLOW IS INCREASING SLIGHTLY AND COULD BE RUNNING INTO LIGHTER FLOW OUT OF THE SOUTHWEST. THE WINDS THEN BECOME MORE- ALIGNED IN THE LOWEST 10KFT LATER TONIGHT. LOWEST CLOUD DECK IS ABOUT 8KFT...SO WILL COUNT ON ANY RAIN FALLING FROM THEM TO MOSTLY DRY UP BEFORE IT GETS TO THE GROUND. STILL...A VERY LIGHT SHOWER IS POSSIBLE THERE FOR THE NEXT FEW HOURS. FROM PREV... SOME OF THE HIGHEST TERRAIN ACROSS THE WEST COULD SEE THE SW WIND STAY UP AT AROUND 5-8 KTS TONIGHT AS THE LLVL P-GRADIENT TIGHTENS A BIT. LOW TEMPS TONIGHT WILL VARY FROM THE LOWER 60S ACROSS THE NRN AND WRN HIGH TERRAIN...TO THE MID 60S IN THE CENTRAL MTNS...AND AROUND 70F IN THE METRO AREAS OF THE LOWER SUSQ VALLEY. && .SHORT TERM /7 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... APPROACHING SHORTWAVE AND ASSOC SFC COLD FRONT WILL BRING A CHANCE OF MAINLY AFTERNOON AND EVENING SHRA/TSRA WEDNESDAY. HIGHEST /LIKELY/ POPS ARE PAINTED ACROSS THE NW MTNS CLOSEST TO APPROACHING COLD FRONT. ALL SHORT RANGE MDLS INDICATE THERE WILL BE A MINIMUM IN SHOWER ACTIVITY ACROSS THE CENTRAL MTNS IN CONJUNCTION WITH LINGERING RIBBON OF LOWER PWATS. PARTLY-MOSTLY CLOUDY SKIES AND SCT PM CONVECTION MAY HOLD TEMPS DOWN A BIT FROM RECENT DAYS. HOWEVER...THE AIR MASS REMAINS VERY WARM WITH MDL 8H TEMPS AOA 18C. EXPECT TEMPS TO TOP OUT WELL INTO THE 80S AGAIN...WITH 90F STILL POSSIBLE ACROSS THE SUSQ VALLEY. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... LITTLE CHANGE IN MEDIUM RANGE MODELS AND EFS TODAY AS TRANSITION FROM HOT AND DRY SUMMERTIME CONDITIONS PERSISTS LATER THIS WEEK INTO THIS WEEKEND. WHILE LEADING SHORTWAVE NUDGES AND DISPLACES RIDGE SLIGHTLY AT MIDWEEK...TRAILING SLOW- MOVING COLD FRONT PASSES THROUGH PENNSYLVANIA LATE WEDNESDAY NIGHT INTO THURSDAY WHILE DEEP UPPER TROF SLOWLY PROPOGATES THROUGH THE GREAT LAKES AND THE OHIO VALLEY THURSDAY AND FRIDAY. BENEFICIAL RAINFALL EXPECTED FROM THIS SLOW MOVING SYSTEM...AND SHOWERS WILL LIKELY LINGER OVER SOUTHEAST PA ON THURSDAY BEFORE EXITING THE EASTERN SEABOARD THU NIGHT. AFTER A FAIR DAY FRIDAY...MOISTURE SHOULD INCREASE AGAIN THROUGHOUT THE DAY SATURDAY AS DEEP UPPER TROF ARRIVES FROM THE OHIO VALLEY. MODELS AND EFS CREATE OHIO VALLEY CUTOFF LOW WHICH WILL KEEP SHOWERY CONDITIONS OVER THE REGION FOR THE REST OF THE WEEKEND BEFORE DRYING ARRIVES TO START THE WEEK...AND HIGH PRESSURE BUILDS OVER THE MIDDLE APPALACHIANS TO THE MID ATLANTIC COAST MON-TUE. THIS WILL ALLOW TEMPS TO REBOUND AFTER A BRIEF DIP SAT-SUN ASSOCIATED WITH THE AFOREMENTIONED CUTOFF. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... STILL A FEW LOW...MID...AND HIGH CLDS AROUND. MAINLY LOOKING AT VFR CONDITIONS TONIGHT INTO WED. SOME FOG POSSIBLE AT BFD FOR AN HOUR OR SO LATE TONIGHT. LIKEWISE SOME POSSIBLE AT LNS. EXPECT IPT TO HAVE SOME FOG LATE...ALONG WITH A LOW CIG. ALL THIS BASED ON A MIX OF GUIDANCE AND WHAT HAPPEN LAST NIGHT. LIMITING FACTOR TONIGHT WILL BE A LITTLE MORE OF A SW BREEZE...AS THE GRADIENT PICKS UP. THIS BEING THE RESULT OF THE LOW TRACKING NE ACROSS THE CENTRAL GREAT LAKES. ALSO DEWPOINTS THIS AFTERNOON HAVE BEEN ON THE DECREASE. THERE COULD BE A SHOWER OR TWO AT BFD ON WED...BUT HARD TO SEE MUCH GOING ON...THUS JUST WENT WITH VCSH AT BFD. 00Z TAFS SENT. A COLD FRONT WILL DRIFT SLOWLY EAST FROM THE GREAT LAKES AND CROSS THE REGION LATE WEDNESDAY AFTERNOON AND WED NIGHT. MAIN CHC FOR SHOWERS WILL BE ACROSS THE WRN MTNS OF PA...COINCIDING WITH PEAK HEATING CLOSE TO THE TIME OF THE CFROPA. CHC FOR SHOWERS WILL DIMINISH ACROSS THE ERN HALF OF PA. OUTLOOK... THU...MORE NUMEROUS SHRA/TSRA EXPECTED. BRIEF IFR CIGS AND VSBYS POSSIBLE. FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR. SAT...SCATTERED SHRA/TSRA. SUN...SCATTERED SHOWERS...MAINLY EASTERN AREAS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...DANGELO/LAMBERT SHORT TERM...FITZGERALD/LAMBERT LONG TERM...DEVOIR/FITZGERALD/CERU AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
131 PM CDT MON SEP 7 2015 .AVIATION UPDATE... ISOLATED STORMS AGAIN POSSIBLE THIS AFTERNOON EAST. ADDITIONALLY...PATCHY MVFR FOG AGAIN EXPECTED TO DEVELOP OVERNIGHT. VFR CONDITIONS LIKELY OTHERWISE WITH WIND SPEEDS NEAR OR LESS THAN 6KNTS. && .PREV DISCUSSION... /ISSUED 632 AM CDT MON SEP 7 2015/ UPDATE... FOR 12Z AVIATION. DISCUSSION... LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW 70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA. POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE 1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. AVIATION... 12Z TAF DISCUSSION. MVFR TO LIFR FOG HAS OCCURRED AT KCKV AND KCSV THIS MORNING...AND COULD CONTINUE UNTIL AROUND 14Z OR SO. OTHERWISE EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE DAY. FOG MAY AGAIN RETURN TONIGHT AND INTO THE EARLY MORNING TOMORROW. WINDS WILL BE LIGHT AND MAINLY OUT OF THE SOUTHEAST TODAY. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 70 90 72 87 / 0 20 10 40 CLARKSVILLE 68 90 70 87 / 0 10 0 30 CROSSVILLE 66 83 68 80 / 10 20 20 50 COLUMBIA 68 89 70 87 / 0 20 10 40 LAWRENCEBURG 68 86 70 86 / 0 20 20 40 WAVERLY 69 89 70 86 / 0 10 10 30 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1213 PM CDT MON SEP 7 2015 .UPDATE... UPDATED FOR 18Z AVIATION DISCUSSION... && .PREV DISCUSSION... /ISSUED 1003 AM CDT MON SEP 7 2015/ UPDATE... ANOTHER HOT AND HUMID DAY IS UPCOMING FOR THE MIDSOUTH. TEMPERATURES ARE ALREADY IN THE LOW TO MID 80S AS OF 10AM. ONCE AGAIN THE HRRR IS OVERDOING AFTERNOON THUNDERSTORM COVERAGE. EXPECT COVERAGE TO BE MINIMAL AT BEST. HIGHS TODAY WILL REACH THE MID 90S WITH HEAT INDICES NEAR 100. NO CHANGES TO THE PREVIOUS FORECAST WERE NECESSARY. PREV DISCUSSION... /ISSUED 317 AM CDT MON SEP 7 2015/ DISCUSSION... THE MID SOUTH WILL REMAIN POSITIONED BETWEEN UPPER LEVEL HIGH PRESSURE OVER THE SOUTHERN PLAINS AND AN UPPER LEVEL LOW PRESSURE SYSTEM OVER GEORGIA TODAY. THIS WILL ALLOW FOR THE CONTINUATION OF DRY...HOT...AND HUMID CONDITIONS. THE UPPER LOW WILL MOVE SOUTHWESTWARD THROUGH TUESDAY AND SHOULD SPREAD ISOLATED SHOWERS AND THUNDERSTORMS INTO PORTIONS OF WEST TENNESSEE NEAR THE TENNESSEE RIVER AND NORTHEAST MISSISSIPPI BY TUESDAY AFTERNOON. ELSEWHERE...DRY AND HOT WEATHER WILL CONTINUE ALONG WITH HUMID CONDITIONS. THE UPPER LEVEL RIDGE EXTENDING OVER THE AREA EARLY IN THE WEEK WILL BREAK DOWN BY WEDNESDAY AS A SHORTWAVE TROUGH DIGS ACROSS THE CENTRAL PLAINS INTO THE LOWER MISSISSIPPI VALLEY. THIS SHOULD INCREASE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE AREA AND KNOCK TEMPERATURES BACK DOWN TO NEAR NORMAL LEVELS FOR THIS TIME OF YEAR. THE UPPER LEVEL TROUGH SHOULD REMAIN OVER THE REGION INTO THURSDAY WITH CONTINUED CHANCES FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. A STRONGER SHORTWAVE WILL DIVE SOUTHEAST INTO THE REGION ON FRIDAY AND HELP TO PUSH A COLD FRONT SOUTH ACROSS THE FORECAST AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN BE POSSIBLE ON FRIDAY AS THE FRONT MOVES THROUGH. SURFACE HIGH PRESSURE SHOULD BUILD INTO THE AREA AS UPPER LEVEL TROUGHING REMAINS OVER THE EASTERN HALF OF THE NATION. DRY WEATHER ALONG WITH COOLER AND LESS HUMID CONDITIONS CAN BE EXPECTED FOR NEXT WEEKEND. BY EARLY NEXT WEEK...ATTENTION WILL TURN TO THE WESTERN GULF OF MEXICO WHERE MODELS ARE HINTING AT POTENTIAL TROPICAL DEVELOPMENT. LATEST GUIDANCE BRINGS ANY DEVELOPING SYSTEM NORTH THROUGH THE ARKLATEX AND INTO OUR REGION EARLY NEXT WEEK. PLAN TO CARRY AN INCREASE IN RAIN CHANCES EARLY NEXT WEEK...BUT WILL NOT GO AS HIGH AS CURRENT GUIDANCE UNTIL THIS SOLUTION LOOKS MORE LIKELY. THIS SCENARIO WILL BE WATCHED CLOSELY OVER THE NEXT SEVERAL DAYS. JLH .AVIATION... 12Z TAF CYCLE VFR CONDITIONS ARE EXPECTED THROUGH THE NEXT 24 HOURS. PATCHY FOG IS ONCE AGAIN POSSIBLE TONIGHT AT MKL...JBR AND TUP BUT SHOULD BURN OFF BY 13Z ON TUESDAY. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1003 AM CDT MON SEP 7 2015 .UPDATE... ANOTHER HOT AND HUMID DAY IS UPCOMING FOR THE MIDSOUTH. TEMPERATURES ARE ALREADY IN THE LOW TO MID 80S AS OF 10AM. ONCE AGAIN THE HRRR IS OVERDOING AFTERNOON THUNDERSTORM COVERAGE. EXPECT COVERAGE TO BE MINIMAL AT BEST. HIGHS TODAY WILL REACH THE MID 90S WITH HEAT INDICES NEAR 100. NO CHANGES TO THE PREVIOUS FORECAST WERE NECESSARY. && .PREV DISCUSSION... /ISSUED 608 AM CDT MON SEP 7 2015/ UPDATE... UPDATED TO ADD 12Z AVIATION DISCUSSION. PREV DISCUSSION... /ISSUED 317 AM CDT MON SEP 7 2015/ DISCUSSION... THE MID SOUTH WILL REMAIN POSITIONED BETWEEN UPPER LEVEL HIGH PRESSURE OVER THE SOUTHERN PLAINS AND AN UPPER LEVEL LOW PRESSURE SYSTEM OVER GEORGIA TODAY. THIS WILL ALLOW FOR THE CONTINUATION OF DRY...HOT...AND HUMID CONDITIONS. THE UPPER LOW WILL MOVE SOUTHWESTWARD THROUGH TUESDAY AND SHOULD SPREAD ISOLATED SHOWERS AND THUNDERSTORMS INTO PORTIONS OF WEST TENNESSEE NEAR THE TENNESSEE RIVER AND NORTHEAST MISSISSIPPI BY TUESDAY AFTERNOON. ELSEWHERE...DRY AND HOT WEATHER WILL CONTINUE ALONG WITH HUMID CONDITIONS. THE UPPER LEVEL RIDGE EXTENDING OVER THE AREA EARLY IN THE WEEK WILL BREAK DOWN BY WEDNESDAY AS A SHORTWAVE TROUGH DIGS ACROSS THE CENTRAL PLAINS INTO THE LOWER MISSISSIPPI VALLEY. THIS SHOULD INCREASE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE AREA AND KNOCK TEMPERATURES BACK DOWN TO NEAR NORMAL LEVELS FOR THIS TIME OF YEAR. THE UPPER LEVEL TROUGH SHOULD REMAIN OVER THE REGION INTO THURSDAY WITH CONTINUED CHANCES FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. A STRONGER SHORTWAVE WILL DIVE SOUTHEAST INTO THE REGION ON FRIDAY AND HELP TO PUSH A COLD FRONT SOUTH ACROSS THE FORECAST AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN BE POSSIBLE ON FRIDAY AS THE FRONT MOVES THROUGH. SURFACE HIGH PRESSURE SHOULD BUILD INTO THE AREA AS UPPER LEVEL TROUGHING REMAINS OVER THE EASTERN HALF OF THE NATION. DRY WEATHER ALONG WITH COOLER AND LESS HUMID CONDITIONS CAN BE EXPECTED FOR NEXT WEEKEND. BY EARLY NEXT WEEK...ATTENTION WILL TURN TO THE WESTERN GULF OF MEXICO WHERE MODELS ARE HINTING AT POTENTIAL TROPICAL DEVELOPMENT. LATEST GUIDANCE BRINGS ANY DEVELOPING SYSTEM NORTH THROUGH THE ARKLATEX AND INTO OUR REGION EARLY NEXT WEEK. PLAN TO CARRY AN INCREASE IN RAIN CHANCES EARLY NEXT WEEK...BUT WILL NOT GO AS HIGH AS CURRENT GUIDANCE UNTIL THIS SOLUTION LOOKS MORE LIKELY. THIS SCENARIO WILL BE WATCHED CLOSELY OVER THE NEXT SEVERAL DAYS. JLH .AVIATION... 12Z TAF CYCLE PATCHY FOG MAY PRODUCE TEMPORARY MVFR/IFR VISIBILITIES AT MKL/JBR THROUGH 07/13Z AND AGAIN LATE TONIGHT AT MKL/JBR/TUP. OTHERWISE...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE PERIOD. LIGHT WINDS WILL BECOME SE WINDS BETWEEN 5-8 KTS AFTER 07/15Z. CJC && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
632 AM CDT MON SEP 7 2015 .UPDATE... FOR 12Z AVIATION. && .DISCUSSION... LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW 70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA. POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE 1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. && .AVIATION... 12Z TAF DISCUSSION. MVFR TO LIFR FOG HAS OCCURRED AT KCKV AND KCSV THIS MORNING...AND COULD CONTINUE UNTIL AROUND 14Z OR SO. OTHERWISE EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE DAY. FOG MAY AGAIN RETURN TONIGHT AND INTO THE EARLY MORNING TOMORROW. WINDS WILL BE LIGHT AND MAINLY OUT OF THE SOUTHEAST TODAY. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 06
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
319 AM CDT MON SEP 7 2015 .DISCUSSION... LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW 70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA. POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE 1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 92 70 92 71 / 20 0 20 10 CLARKSVILLE 93 67 92 69 / 10 0 10 0 CROSSVILLE 84 65 84 67 / 20 10 20 20 COLUMBIA 91 67 91 69 / 10 0 20 10 LAWRENCEBURG 89 68 89 69 / 10 0 20 20 WAVERLY 91 67 92 69 / 10 0 10 10 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHAMBURGER
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1045 PM CDT TUE SEP 8 2015 .AVIATION... NO REAL CHANGES FROM FORECAST OF SIX HOURS AGO. UNEVENTFUL WEATHER EXPECTED TONIGHT UNTIL ONSET OF FOG AND LOW CLOUDS BETWEEN 11Z AND 15Z WEDNESDAY. EXPECT RAPID CLEARING WITH GENERALLY CLEAR SKY DURING MOST OF DAYTIME HOURS AND WEDNESDAY EVENING. SURFACE WINDS EXPECTED TO VEER TO SOUTHEAST BY WEDNESDAY AFTERNOON. COCKRELL && .PREV DISCUSSION... /ISSUED 939 PM CDT TUE SEP 8 2015/ UPDATE... HAVE UPDATED GRAPHICAL FORECASTS...ELIMINATING OR LOWERING POPS SUBSTANTIALLY FOR TONIGHT. RADAR TRENDS SUGGEST LITTLE ADDITIONAL THUNDERSTORM DEVELOPMENT IS LIKELY FOR MOST OF THE AREA. UPDATED TEXT PRODUCTS WILL BE ISSUED SHORTLY. COCKRELL PREV DISCUSSION... /ISSUED 640 PM CDT TUE SEP 8 2015/ AVIATION... COLD FRONT HAS CLEARED ALL OF FORECAST AREA...WITH NO THUNDERSTORMS EXPECTED AT TERMINALS THIS EVENING OR OVERNIGHT. WILL CONTINUE TO MONITOR CONVECTION IN NORTHEASTERN NEW MEXICO IN CASE THOSE SHOWERS AND THUNDERSTORMS POSE A THREAT TO KDHT. LIGHT NORTHEAST SURFACE WINDS EXPECTED TO PREVAIL TONIGHT...WITH POTENTIAL FOR FOG AND STRATUS TO DEVELOP WEDNESDAY MORNING. FOR NOW...WILL FORECAST PREVAILING VFR VISIBILITIES AND SKY...WITH OCCASIONAL MVFR VISIBILITIES AND IFR CEILINGS BETWEEN 11Z AND 15Z WEDNESDAY. VFR CONDITIONS EXPECTED TO PREVAIL THEREAFTER AS SURFACE WINDS VEER TO EAST AND SOUTHEAST DURING THE DAY BELOW A GENERALLY CLEAR SKY. COCKRELL PREV DISCUSSION... /ISSUED 242 PM CDT TUE SEP 8 2015/ DISCUSSION... LATEST SURFACE OBS SHOWS THE COLD FRONT EXTENDING FROM JUST NORTH OF WHEELER SOUTHWESTWARD TO NEAR CLAUDE. MORNING SOUNDING INDICATES CONSIDERABLE MOISTENING IN THE MID LEVELS AS EVIDENT BY WIDESPREAD ALTOSTRATUS OBSERVED ACROSS MOST OF THE AREA. POST FRONTAL AIR MASS IS RELATIVELY COOL ESPECIALLY WHERE MID CLOUDS ARE MOST EXTENSIVE. TEMPERATURES AT 19Z RANGE FROM THE MID 70S TO THE MID 80S BEHIND THE FRONT. DESPITE MOIST ADVECTION BEHIND THE FRONT IN THE NORTHEAST...DIABATIC HEATING HAS BEEN INSUFFICIENT FOR MEANINGFUL INSTABILITY TO DEVELOP. TEMPERATURES WERE NEAR 100 DEGREES IN THE FAR SOUTHEAST WHERE SOUTHWESTERLY SURFACE WINDS PREVAIL AND CLOUD COVER HAS BEEN LIMITED. THIS IS WHERE INSTABILITY HAS INCREASED THE MOST AND GIVEN LOW/MID 60 DEGREE DEW POINTS MODERATE INSTABILITY HAS DEVELOPED DESPITE WEAK MID LEVEL LAPSE RATES. SO FAR CONVECTION HAS BEEN RELATIVELY BENIGN AND CONFINED MOSTLY TO ALONG AND JUST BEHIND THE FRONT ACROSS EAST CENTRAL AND NORTHEAST PORTIONS OF THE TEXAS PANHANDLE. SOME INTENSIFICATION SHOULD OCCUR LATER THIS AFTERNOON BUT CHANCES WILL DECREASE FAIRLY QUICKLY LATER THIS AFTERNOON AND ESPECIALLY BY EVENING AS LIFT ASSOCIATED WITH A WEAK SHORTWAVE SHIFTS EASTWARD INTO OKLAHOMA. THIS SHORTWAVE IS DIFFICULT TO SEE BUT SOME INDICATION IN WATER VAPOR IMAGERY AND RAP PV ANALYSIS SUPPORTS TRENDS SEEN ON RADAR. MODERATE INSTABILITY IN THE SOUTHEAST AND EAST CENTRAL TEXAS PANHANDLE RAISES SOME CONCERN FOR SEVERE POTENTIAL. A MISALIGNMENT OF BEST SHEAR BEHIND THE FRONT (WHERE NORTHERLY/NORTHEASTERLY FLOW EXISTS) FROM THE MOST SIGNIFICANT INSTABILITY SOUTHEAST OF THE FRONT IS A NEGATIVE FACTOR. WEAKLY ORGANIZED UPDRAFTS IN THE SOUTHEAST PART OF THE TEXAS PANHANDLE THROUGH THE AFTERNOON INTO THE EARLY EVENING COULD RESULT IN BRIEF/ISOLATED MARGINALLY SEVERE HAIL OR WIND GUSTS. LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN MODEST STORM MOTIONS AND A MOIST ENVIRONMENT WITH PWATS AROUND AN INCH AND A HALF. HAVE SCALED BACK PRECIPITATION PROBABILITIES LATER TONIGHT BASED ON TRENDS AND AM QUITE CONFIDENT IN A DRY FORECAST FOR TOMORROW. POST FRONTAL ENVIRONMENT WILL BE COOLER BUT ONLY SLIGHTLY BELOW NORMAL VALUES FOR EARLY TO MID SEPTEMBER. DURING THE MID WEEK PERIOD BROAD CYCLONIC FAIRLY SWIFT MID/UPPER FLOW WILL COVER MUCH OF THE NORTHERN PORTIONS OF THE COUNTRY. OVERALL NOT MUCH CHANGE WAS MADE TO THE PREVIOUS FORECAST. THE CHALLENGE WILL SHIFT TOWARD RESOLVING FAST MOVING SHORTWAVE TROUGHS EMBEDDED WITHIN THE LARGER UPPER LOW OVER EASTERN CANADA THROUGH THE END OF THE WEEK. MODELS BRING THE FIRST WAVE THROUGH THE CENTRAL PLAINS LATE THURSDAY THROUGH EARLY FRIDAY FORCING ANOTHER COLD FRONT THROUGH. CONTINUED THE TREND OF DOWNPLAYING DAYTIME PRECIPITATION CHANCES ACROSS MUCH OF THE REGION EXPECT THE NORTHERN TEXAS PANHANDLE AND OKLAHOMA PANHANDLE. CHANCES SPREAD SOUTH THROUGH THE NIGHT. GIVEN BETTER MODEL AGREEMENT WE NOW HAVE HIGHER CONFIDENCE ON COOLER WEATHER ON FRIDAY BEHIND THE FRONT WHICH SHOULD PERSIST INTO SATURDAY. TEMPERATURES RETURN TO NEAR NORMAL LEVELS SUNDAY INTO THE BEGINNING OF NEXT WEEK AS UPPER FLOW PATTERN AMPLIFIES FURTHER. THE VERY PRONOUNCED WAVE IN THE GFS MODEL EMBEDDED WITHIN THE NORTH-NORTHWESTERLY FLOW BETWEEN BUILDING RIDGE IN THE WEST AND DEEPENING TROUGH IN THE EAST THIS WEEKEND IS FURTHER EAST AND NOT QUITE AS PRONOUNCED. THIS IS MORE IN LINE WITH OTHER MEDIUM RANGE GUIDANCE AND WAS ENOUGH FOR US TO KEEP THE LATTER PORTION OF THE EXTENDED DRY FOR NOW. BRB && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 3/10
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
939 PM CDT TUE SEP 8 2015 .UPDATE... HAVE UPDATED GRAPHICAL FORECASTS...ELIMINATING OR LOWERING POPS SUBSTANTIALLY FOR TONIGHT. RADAR TRENDS SUGGEST LITTLE ADDITIONAL THUNDERSTORM DEVELOPMENT IS LIKELY FOR MOST OF THE AREA. UPDATED TEXT PRODUCTS WILL BE ISSUED SHORTLY. COCKRELL && .PREV DISCUSSION... /ISSUED 640 PM CDT TUE SEP 8 2015/ AVIATION... COLD FRONT HAS CLEARED ALL OF FORECAST AREA...WITH NO THUNDERSTORMS EXPECTED AT TERMINALS THIS EVENING OR OVERNIGHT. WILL CONTINUE TO MONITOR CONVECTION IN NORTHEASTERN NEW MEXICO IN CASE THOSE SHOWERS AND THUNDERSTORMS POSE A THREAT TO KDHT. LIGHT NORTHEAST SURFACE WINDS EXPECTED TO PREVAIL TONIGHT...WITH POTENTIAL FOR FOG AND STRATUS TO DEVELOP WEDNESDAY MORNING. FOR NOW...WILL FORECAST PREVAILING VFR VISIBILITIES AND SKY...WITH OCCASIONAL MVFR VISIBILITIES AND IFR CEILINGS BETWEEN 11Z AND 15Z WEDNESDAY. VFR CONDITIONS EXPECTED TO PREVAIL THEREAFTER AS SURFACE WINDS VEER TO EAST AND SOUTHEAST DURING THE DAY BELOW A GENERALLY CLEAR SKY. COCKRELL PREV DISCUSSION... /ISSUED 242 PM CDT TUE SEP 8 2015/ DISCUSSION... LATEST SURFACE OBS SHOWS THE COLD FRONT EXTENDING FROM JUST NORTH OF WHEELER SOUTHWESTWARD TO NEAR CLAUDE. MORNING SOUNDING INDICATES CONSIDERABLE MOISTENING IN THE MID LEVELS AS EVIDENT BY WIDESPREAD ALTOSTRATUS OBSERVED ACROSS MOST OF THE AREA. POST FRONTAL AIR MASS IS RELATIVELY COOL ESPECIALLY WHERE MID CLOUDS ARE MOST EXTENSIVE. TEMPERATURES AT 19Z RANGE FROM THE MID 70S TO THE MID 80S BEHIND THE FRONT. DESPITE MOIST ADVECTION BEHIND THE FRONT IN THE NORTHEAST...DIABATIC HEATING HAS BEEN INSUFFICIENT FOR MEANINGFUL INSTABILITY TO DEVELOP. TEMPERATURES WERE NEAR 100 DEGREES IN THE FAR SOUTHEAST WHERE SOUTHWESTERLY SURFACE WINDS PREVAIL AND CLOUD COVER HAS BEEN LIMITED. THIS IS WHERE INSTABILITY HAS INCREASED THE MOST AND GIVEN LOW/MID 60 DEGREE DEW POINTS MODERATE INSTABILITY HAS DEVELOPED DESPITE WEAK MID LEVEL LAPSE RATES. SO FAR CONVECTION HAS BEEN RELATIVELY BENIGN AND CONFINED MOSTLY TO ALONG AND JUST BEHIND THE FRONT ACROSS EAST CENTRAL AND NORTHEAST PORTIONS OF THE TEXAS PANHANDLE. SOME INTENSIFICATION SHOULD OCCUR LATER THIS AFTERNOON BUT CHANCES WILL DECREASE FAIRLY QUICKLY LATER THIS AFTERNOON AND ESPECIALLY BY EVENING AS LIFT ASSOCIATED WITH A WEAK SHORTWAVE SHIFTS EASTWARD INTO OKLAHOMA. THIS SHORTWAVE IS DIFFICULT TO SEE BUT SOME INDICATION IN WATER VAPOR IMAGERY AND RAP PV ANALYSIS SUPPORTS TRENDS SEEN ON RADAR. MODERATE INSTABILITY IN THE SOUTHEAST AND EAST CENTRAL TEXAS PANHANDLE RAISES SOME CONCERN FOR SEVERE POTENTIAL. A MISALIGNMENT OF BEST SHEAR BEHIND THE FRONT (WHERE NORTHERLY/NORTHEASTERLY FLOW EXISTS) FROM THE MOST SIGNIFICANT INSTABILITY SOUTHEAST OF THE FRONT IS A NEGATIVE FACTOR. WEAKLY ORGANIZED UPDRAFTS IN THE SOUTHEAST PART OF THE TEXAS PANHANDLE THROUGH THE AFTERNOON INTO THE EARLY EVENING COULD RESULT IN BRIEF/ISOLATED MARGINALLY SEVERE HAIL OR WIND GUSTS. LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN MODEST STORM MOTIONS AND A MOIST ENVIRONMENT WITH PWATS AROUND AN INCH AND A HALF. HAVE SCALED BACK PRECIPITATION PROBABILITIES LATER TONIGHT BASED ON TRENDS AND AM QUITE CONFIDENT IN A DRY FORECAST FOR TOMORROW. POST FRONTAL ENVIRONMENT WILL BE COOLER BUT ONLY SLIGHTLY BELOW NORMAL VALUES FOR EARLY TO MID SEPTEMBER. DURING THE MID WEEK PERIOD BROAD CYCLONIC FAIRLY SWIFT MID/UPPER FLOW WILL COVER MUCH OF THE NORTHERN PORTIONS OF THE COUNTRY. OVERALL NOT MUCH CHANGE WAS MADE TO THE PREVIOUS FORECAST. THE CHALLENGE WILL SHIFT TOWARD RESOLVING FAST MOVING SHORTWAVE TROUGHS EMBEDDED WITHIN THE LARGER UPPER LOW OVER EASTERN CANADA THROUGH THE END OF THE WEEK. MODELS BRING THE FIRST WAVE THROUGH THE CENTRAL PLAINS LATE THURSDAY THROUGH EARLY FRIDAY FORCING ANOTHER COLD FRONT THROUGH. CONTINUED THE TREND OF DOWNPLAYING DAYTIME PRECIPITATION CHANCES ACROSS MUCH OF THE REGION EXPECT THE NORTHERN TEXAS PANHANDLE AND OKLAHOMA PANHANDLE. CHANCES SPREAD SOUTH THROUGH THE NIGHT. GIVEN BETTER MODEL AGREEMENT WE NOW HAVE HIGHER CONFIDENCE ON COOLER WEATHER ON FRIDAY BEHIND THE FRONT WHICH SHOULD PERSIST INTO SATURDAY. TEMPERATURES RETURN TO NEAR NORMAL LEVELS SUNDAY INTO THE BEGINNING OF NEXT WEEK AS UPPER FLOW PATTERN AMPLIFIES FURTHER. THE VERY PRONOUNCED WAVE IN THE GFS MODEL EMBEDDED WITHIN THE NORTH-NORTHWESTERLY FLOW BETWEEN BUILDING RIDGE IN THE WEST AND DEEPENING TROUGH IN THE EAST THIS WEEKEND IS FURTHER EAST AND NOT QUITE AS PRONOUNCED. THIS IS MORE IN LINE WITH OTHER MEDIUM RANGE GUIDANCE AND WAS ENOUGH FOR US TO KEEP THE LATTER PORTION OF THE EXTENDED DRY FOR NOW. BRB && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 03/10
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
640 PM CDT TUE SEP 8 2015 .AVIATION... COLD FRONT HAS CLEARED ALL OF FORECAST AREA...WITH NO THUNDERSTORMS EXPECTED AT TERMINALS THIS EVENING OR OVERNIGHT. WILL CONTINUE TO MONITOR CONVECTION IN NORTHEASTERN NEW MEXICO IN CASE THOSE SHOWERS AND THUNDERSTORMS POSE A THREAT TO KDHT. LIGHT NORTHEAST SURFACE WINDS EXPECTED TO PREVAIL TONIGHT...WITH POTENTIAL FOR FOG AND STRATUS TO DEVELOP WEDNESDAY MORNING. FOR NOW...WILL FORECAST PREVAILING VFR VISIBILITIES AND SKY...WITH OCCASIONAL MVFR VISIBILITIES AND IFR CEILINGS BETWEEN 11Z AND 15Z WEDNESDAY. VFR CONDITIONS EXPECTED TO PREVAIL THEREAFTER AS SURFACE WINDS VEER TO EAST AND SOUTHEAST DURING THE DAY BELOW A GENERALLY CLEAR SKY. COCKRELL && .PREV DISCUSSION... /ISSUED 242 PM CDT TUE SEP 8 2015/ DISCUSSION... LATEST SURFACE OBS SHOWS THE COLD FRONT EXTENDING FROM JUST NORTH OF WHEELER SOUTHWESTWARD TO NEAR CLAUDE. MORNING SOUNDING INDICATES CONSIDERABLE MOISTENING IN THE MID LEVELS AS EVIDENT BY WIDESPREAD ALTOSTRATUS OBSERVED ACROSS MOST OF THE AREA. POST FRONTAL AIR MASS IS RELATIVELY COOL ESPECIALLY WHERE MID CLOUDS ARE MOST EXTENSIVE. TEMPERATURES AT 19Z RANGE FROM THE MID 70S TO THE MID 80S BEHIND THE FRONT. DESPITE MOIST ADVECTION BEHIND THE FRONT IN THE NORTHEAST...DIABATIC HEATING HAS BEEN INSUFFICIENT FOR MEANINGFUL INSTABILITY TO DEVELOP. TEMPERATURES WERE NEAR 100 DEGREES IN THE FAR SOUTHEAST WHERE SOUTHWESTERLY SURFACE WINDS PREVAIL AND CLOUD COVER HAS BEEN LIMITED. THIS IS WHERE INSTABILITY HAS INCREASED THE MOST AND GIVEN LOW/MID 60 DEGREE DEW POINTS MODERATE INSTABILITY HAS DEVELOPED DESPITE WEAK MID LEVEL LAPSE RATES. SO FAR CONVECTION HAS BEEN RELATIVELY BENIGN AND CONFINED MOSTLY TO ALONG AND JUST BEHIND THE FRONT ACROSS EAST CENTRAL AND NORTHEAST PORTIONS OF THE TEXAS PANHANDLE. SOME INTENSIFICATION SHOULD OCCUR LATER THIS AFTERNOON BUT CHANCES WILL DECREASE FAIRLY QUICKLY LATER THIS AFTERNOON AND ESPECIALLY BY EVENING AS LIFT ASSOCIATED WITH A WEAK SHORTWAVE SHIFTS EASTWARD INTO OKLAHOMA. THIS SHORTWAVE IS DIFFICULT TO SEE BUT SOME INDICATION IN WATER VAPOR IMAGERY AND RAP PV ANALYSIS SUPPORTS TRENDS SEEN ON RADAR. MODERATE INSTABILITY IN THE SOUTHEAST AND EAST CENTRAL TEXAS PANHANDLE RAISES SOME CONCERN FOR SEVERE POTENTIAL. A MISALIGNMENT OF BEST SHEAR BEHIND THE FRONT (WHERE NORTHERLY/NORTHEASTERLY FLOW EXISTS) FROM THE MOST SIGNIFICANT INSTABILITY SOUTHEAST OF THE FRONT IS A NEGATIVE FACTOR. WEAKLY ORGANIZED UPDRAFTS IN THE SOUTHEAST PART OF THE TEXAS PANHANDLE THROUGH THE AFTERNOON INTO THE EARLY EVENING COULD RESULT IN BRIEF/ISOLATED MARGINALLY SEVERE HAIL OR WIND GUSTS. LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN MODEST STORM MOTIONS AND A MOIST ENVIRONMENT WITH PWATS AROUND AN INCH AND A HALF. HAVE SCALED BACK PRECIPITATION PROBABILITIES LATER TONIGHT BASED ON TRENDS AND AM QUITE CONFIDENT IN A DRY FORECAST FOR TOMORROW. POST FRONTAL ENVIRONMENT WILL BE COOLER BUT ONLY SLIGHTLY BELOW NORMAL VALUES FOR EARLY TO MID SEPTEMBER. DURING THE MID WEEK PERIOD BROAD CYCLONIC FAIRLY SWIFT MID/UPPER FLOW WILL COVER MUCH OF THE NORTHERN PORTIONS OF THE COUNTRY. OVERALL NOT MUCH CHANGE WAS MADE TO THE PREVIOUS FORECAST. THE CHALLENGE WILL SHIFT TOWARD RESOLVING FAST MOVING SHORTWAVE TROUGHS EMBEDDED WITHIN THE LARGER UPPER LOW OVER EASTERN CANADA THROUGH THE END OF THE WEEK. MODELS BRING THE FIRST WAVE THROUGH THE CENTRAL PLAINS LATE THURSDAY THROUGH EARLY FRIDAY FORCING ANOTHER COLD FRONT THROUGH. CONTINUED THE TREND OF DOWNPLAYING DAYTIME PRECIPITATION CHANCES ACROSS MUCH OF THE REGION EXPECT THE NORTHERN TEXAS PANHANDLE AND OKLAHOMA PANHANDLE. CHANCES SPREAD SOUTH THROUGH THE NIGHT. GIVEN BETTER MODEL AGREEMENT WE NOW HAVE HIGHER CONFIDENCE ON COOLER WEATHER ON FRIDAY BEHIND THE FRONT WHICH SHOULD PERSIST INTO SATURDAY. TEMPERATURES RETURN TO NEAR NORMAL LEVELS SUNDAY INTO THE BEGINNING OF NEXT WEEK AS UPPER FLOW PATTERN AMPLIFIES FURTHER. THE VERY PRONOUNCED WAVE IN THE GFS MODEL EMBEDDED WITHIN THE NORTH-NORTHWESTERLY FLOW BETWEEN BUILDING RIDGE IN THE WEST AND DEEPENING TROUGH IN THE EAST THIS WEEKEND IS FURTHER EAST AND NOT QUITE AS PRONOUNCED. THIS IS MORE IN LINE WITH OTHER MEDIUM RANGE GUIDANCE AND WAS ENOUGH FOR US TO KEEP THE LATTER PORTION OF THE EXTENDED DRY FOR NOW. BRB && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 62 82 60 87 61 / 10 5 5 20 20 BEAVER OK 63 83 61 91 62 / 5 5 0 20 40 BOISE CITY OK 58 82 59 89 60 / 20 5 5 30 30 BORGER TX 63 85 63 90 64 / 10 5 5 20 40 BOYS RANCH TX 62 84 60 89 60 / 10 5 5 20 20 CANYON TX 63 82 59 88 61 / 20 5 5 20 20 CLARENDON TX 63 82 62 88 64 / 20 10 5 10 20 DALHART TX 58 83 59 89 59 / 20 5 5 30 30 GUYMON OK 63 84 61 90 61 / 5 5 0 30 40 HEREFORD TX 63 81 60 87 60 / 20 5 5 20 20 LIPSCOMB TX 63 83 61 89 61 / 10 0 0 20 40 PAMPA TX 62 82 61 87 60 / 20 5 0 10 40 SHAMROCK TX 65 84 62 89 63 / 20 5 0 5 30 WELLINGTON TX 66 85 62 90 65 / 30 5 0 5 20 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 03/10
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
636 PM CDT TUE SEP 8 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE MOSTLY CLEAR SKIES ACROSS THE CWA EARLY THIS EVENING. EXPECT VFR CONDITIONS TO PREVAIL THE REST OF THE EVENING INTO EARLY WED MORNING AS NORTHERLY WINDS ALOFT CONTINUE TO PROVIDE SUBSIDENCE ACROSS THE RIO GRANDE VALLEY. A 500MB LOW ACROSS THE NORTH CENTRAL GULF OF MEXICO WILL MOVE ACROSS THE WESTERN GULF OF MEXICO WEDNESDAY. THIS WILL ALLOW LOW TO MID LEVEL MOISTURE TO INCREASE ACROSS THE COASTAL SECTIONS OF THE CWA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND WED AFTERNOON. && .PREV DISCUSSION... /ISSUED 300 PM CDT TUE SEP 8 2015/ SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AN ACTIVE SEA BREEZE IS MOVING SLOWLY INLAND THIS AFTERNOON. THE HRRR SUGGESTS THAT IT WILL PUSH INTO THE MID VALLEY. DRIER AIR IS STILL IN PLACE FARTHER WEST. SKIES SHOULD BECOME MOSTLY CLEAR TONIGHT. WV IMAGERY SHOWS A MID LEVEL CIRCULATION SOUTH OF LOUISIANA...WHICH IS PROGGED TO DRIFT SOUTHWEST TOWARD THE AREA. THUS...LOOK FOR CONTINUED UNSETTLED CONDITIONS OVER THE GULF...WITH A FEW SHOWERS TRANSLATING FARTHER WEST OVER THE COAST TONIGHT. THE NAM SHOWS DRIER AIR AGAIN OUT WEST ON WEDNESDAY...SO WILL ANTICIPATE SIMILAR CONDITIONS AS TODAY WITH MAYBE A LITTLE MORE ACTIVITY OVER THE COASTAL AREAS. THE MOISTURE POOLING ALONG AND AHEAD OF A FRONT MOVING SOUTH OVER CENTRAL TEXAS WILL NOT BE FAR ENOUGH SOUTH TO CAUSE A MAJOR PROBLEM IN THE SHORT TERM...EXCEPT PERHAPS FOR A FEW SHOWERS OVER THE FAR NORTHWEST... ZAPATA COUNTY...WEDNESDAY NIGHT. LONG TERM /THURSDAY THROUGH TUESDAY/... H5 TROUGH REMAINS BOTTLED BETWEEN 2 RIDGES...WITH THE AXIS REMAINING TO THE EAST ON THURSDAY. THIS WILL KEEP THE REGION ON THE DRIER WEST SIDE THURSDAY AND INTO FRIDAY. FRIDAY BRINGS THE TROUGH AXIS WESTWARD AS THE OVERALL TROUGH DEEPENS. AN INCREASE IN MOISTURE FROM THE SOUTH WILL BEGIN TO RAMP UP POPS LATER FRIDAY AFTERNOON. GOOD DEEP MOISTURE AND INSTABILITY COMBINES ON SATURDAY FOR A GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS. SUNDAY INTO MONDAY A WEAK COLD FRONT TRIES TO MOVE SOUTHWARD INTO SOUTH TEXAS. THE MAIN ISSUE IS SOUTHWARD MOVING DRIER AIR AND HOW FAR SOUTH IT WILL REACH...CLASHING WITH GULF MOISTURE MOVING BACK TO THE NORTH. CONTINUING WITH A GOOD CHANCE FOR THUNDERSTORMS BOTH DAYS AS INSTABILITY REMAINS DECENT. QUESTION MARKS CROP UP STARTING EARLY NEXT WEEK AS MODELS DIFFER ON WHAT HAPPENS TO THE REMNANTS OF THE FRONT. NEEDLESS TO SAY...A DEGRADING FRONT HOVERING IN THE WESTERN GULF NEEDS TO HAVE A CLOSE EYE KEPT ON IT. FOR NOW...THE LOCALIZED INSTABILITY RAIN CHANCES CONTINUE TUESDAY INTO WEDNESDAY...ESPECIALLY CLOSER TO THE COAST...AS WE MOVE INTO OUR CLIMATOLOGICALLY WETTEST WEEK OF THE ENTIRE YEAR. MARINE... A WEAK PRESSURE GRADIENT WILL CAUSE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND LOW TO MODERATE SEAS TO PERSIST ALONG THE LOWER TEXAS COAST. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 61/55/BIRCHFIELD
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1200 PM CDT MON SEP 7 2015 .AVIATION... /12Z TAFS/ Expect VFR conditions at the terminals the next 24 hours. The winds will be south at 5 to 10 knots. && .PREV DISCUSSION... /ISSUED 628 AM CDT MON SEP 7 2015/ AVIATION... /12Z TAFS/ MVFR stratus in the Hill Country was advecting north to the I-10 corridor from Sonora to Junction at 11Z. Will include a tempo for MVFR ceiling at KSOA and KJCT through 16Z. Otherwise, south to southeast winds of 10 KTS or less, and VFR conditions are expected across the rest of the terminals. PREV DISCUSSION... /ISSUED 356 AM CDT MON SEP 7 2015/ SHORT TERM... (Today and Tonight) It will be another persistence forecast today, with the upper ridge parked over West Central Texas. The HRRR model again develops isolated afternoon convection, as it has done the last several days, and will discount the potential. Temperatures should again rise into the upper 90s with a few areas reaching 100. 04 LONG TERM... (Tuesday through Sunday) We looking for one more hot and dry day across west central TX before the synoptic pattern shifts to one more conducive for increasing rain chances and more seasonal temperatures. The subtropical ridge will be building slowly westward on Tuesday as a strong trough moves across the northern Plains. This trough is progged to dig over the eastern CONUS, allowing the ridge to build over the western states. This will result in northwest flow aloft for our neck of the woods. A weak cold front will move south into the Lone Star State Tuesday afternoon, likely reaching the south Plains during the evening hours. Compressional heating ahead of this cold front will promote afternoon highs in the mid 90s to near 100 degrees. Convection is expected to initiate along this cold front as it approaches Tuesday evening. Some of this activity is expected to move southeast into the Big Country, maybe as far south as the Colorado River, Tuesday night into early Wednesday morning. The cold front is expected to weaken by this time, but convective outflow should serve as the effective frontal boundary, moving south into the Concho Valley, and eventually the I-10 corridor, by Wednesday afternoon. Scattered showers and thunderstorms are expected to develop, especially along and behind the front. While rainfall is not expected to be particularly heavy, it should be fairly widespread with good coverage across the CWA. The increased cloud cover and precipitation will keep temperatures in check. Forecast highs for Wednesday afternoon are in the upper 80s to lower 90s; however, they could be lowered further if rain is indeed as widespread as anticipated. The effective cold front will move south over the Edwards Plateau Wednesday night into Thursday. This will shift the highest rain chances south of a San Angelo-Brownwood line, favoring the I-10 corridor. In fact, PoPs were removed for areas north of I-20 on Thursday. This boundary will become more diffuse by the end of the work-week, but slight chance PoPs were retained over the southern 1/3 of the CWA for Friday. Total rainfall amounts will likely average less than 1/2 inch, some some areas will see locally higher amounts, especially over the southeast quadrant of the CWA. Temperatures are forecast to remain near seasonal norms Thursday and Friday, generally in the upper 80s to lower 90s. Overnight lows during this time will be in the mid 60s to near 70 degrees. PoPs were removed over the weekend as the main upper-level trough is expected to be to our east by Saturday. Temperatures are expected to remain near climatology. There remain some differences in the synoptic pattern, the most notable of which is the tropical system generated early next week in the western Gulf by the ECMWF. At the same time, the GFS creates no such system and maintains a weak cut-off upper-low over the Red River. Will continue to monitor the model trends at this time, keeping a dry forecast over the weekend. Johnson && .PRELIMINARY POINT TEMPS/POPS... Abilene 99 76 98 73 / 0 0 5 30 San Angelo 100 75 100 74 / 0 0 0 10 Junction 98 74 97 75 / 0 0 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ 21
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
628 AM CDT MON SEP 7 2015 .AVIATION... /12Z TAFS/ MVFR stratus in the Hill Country was advecting north to the I-10 corridor from Sonora to Junction at 11Z. Will include a tempo for MVFR ceiling at KSOA and KJCT through 16Z. Otherwise, south to southeast winds of 10 KTS or less, and VFR conditions are expected across the rest of the terminals. && .PREV DISCUSSION... /ISSUED 356 AM CDT MON SEP 7 2015/ SHORT TERM... (Today and Tonight) It will be another persistence forecast today, with the upper ridge parked over West Central Texas. The HRRR model again develops isolated afternoon convection, as it has done the last several days, and will discount the potential. Temperatures should again rise into the upper 90s with a few areas reaching 100. 04 LONG TERM... (Tuesday through Sunday) We looking for one more hot and dry day across west central TX before the synoptic pattern shifts to one more conducive for increasing rain chances and more seasonal temperatures. The subtropical ridge will be building slowly westward on Tuesday as a strong trough moves across the northern Plains. This trough is progged to dig over the eastern CONUS, allowing the ridge to build over the western states. This will result in northwest flow aloft for our neck of the woods. A weak cold front will move south into the Lone Star State Tuesday afternoon, likely reaching the south Plains during the evening hours. Compressional heating ahead of this cold front will promote afternoon highs in the mid 90s to near 100 degrees. Convection is expected to initiate along this cold front as it approaches Tuesday evening. Some of this activity is expected to move southeast into the Big Country, maybe as far south as the Colorado River, Tuesday night into early Wednesday morning. The cold front is expected to weaken by this time, but convective outflow should serve as the effective frontal boundary, moving south into the Concho Valley, and eventually the I-10 corridor, by Wednesday afternoon. Scattered showers and thunderstorms are expected to develop, especially along and behind the front. While rainfall is not expected to be particularly heavy, it should be fairly widespread with good coverage across the CWA. The increased cloud cover and precipitation will keep temperatures in check. Forecast highs for Wednesday afternoon are in the upper 80s to lower 90s; however, they could be lowered further if rain is indeed as widespread as anticipated. The effective cold front will move south over the Edwards Plateau Wednesday night into Thursday. This will shift the highest rain chances south of a San Angelo-Brownwood line, favoring the I-10 corridor. In fact, PoPs were removed for areas north of I-20 on Thursday. This boundary will become more diffuse by the end of the work-week, but slight chance PoPs were retained over the southern 1/3 of the CWA for Friday. Total rainfall amounts will likely average less than 1/2 inch, some some areas will see locally higher amounts, especially over the southeast quadrant of the CWA. Temperatures are forecast to remain near seasonal norms Thursday and Friday, generally in the upper 80s to lower 90s. Overnight lows during this time will be in the mid 60s to near 70 degrees. PoPs were removed over the weekend as the main upper-level trough is expected to be to our east by Saturday. Temperatures are expected to remain near climatology. There remain some differences in the synoptic pattern, the most notable of which is the tropical system generated early next week in the western Gulf by the ECMWF. At the same time, the GFS creates no such system and maintains a weak cut-off upper-low over the Red River. Will continue to monitor the model trends at this time, keeping a dry forecast over the weekend. Johnson && .PRELIMINARY POINT TEMPS/POPS... Abilene 99 76 98 73 / 0 0 5 30 San Angelo 100 75 100 74 / 0 0 0 10 Junction 98 74 97 75 / 0 0 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ 99/99/04
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
356 AM CDT MON SEP 7 2015 .SHORT TERM... (Today and Tonight) It will be another persistence forecast today, with the upper ridge parked over West Central Texas. The HRRR model again develops isolated afternoon convection, as it has done the last several days, and will discount the potential. Temperatures should again rise into the upper 90s with a few areas reaching 100. 04 .LONG TERM... (Tuesday through Sunday) We looking for one more hot and dry day across west central TX before the synoptic pattern shifts to one more conducive for increasing rain chances and more seasonal temperatures. The subtropical ridge will be building slowly westward on Tuesday as a strong trough moves across the northern Plains. This trough is progged to dig over the eastern CONUS, allowing the ridge to build over the western states. This will result in northwest flow aloft for our neck of the woods. A weak cold front will move south into the Lone Star State Tuesday afternoon, likely reaching the south Plains during the evening hours. Compressional heating ahead of this cold front will promote afternoon highs in the mid 90s to near 100 degrees. Convection is expected to initiate along this cold front as it approaches Tuesday evening. Some of this activity is expected to move southeast into the Big Country, maybe as far south as the Colorado River, Tuesday night into early Wednesday morning. The cold front is expected to weaken by this time, but convective outflow should serve as the effective frontal boundary, moving south into the Concho Valley, and eventually the I-10 corridor, by Wednesday afternoon. Scattered showers and thunderstorms are expected to develop, especially along and behind the front. While rainfall is not expected to be particularly heavy, it should be fairly widespread with good coverage across the CWA. The increased cloud cover and precipitation will keep temperatures in check. Forecast highs for Wednesday afternoon are in the upper 80s to lower 90s; however, they could be lowered further if rain is indeed as widespread as anticipated. The effective cold front will move south over the Edwards Plateau Wednesday night into Thursday. This will shift the highest rain chances south of a San Angelo-Brownwood line, favoring the I-10 corridor. In fact, PoPs were removed for areas north of I-20 on Thursday. This boundary will become more diffuse by the end of the work-week, but slight chance PoPs were retained over the southern 1/3 of the CWA for Friday. Total rainfall amounts will likely average less than 1/2 inch, some some areas will see locally higher amounts, especially over the southeast quadrant of the CWA. Temperatures are forecast to remain near seasonal norms Thursday and Friday, generally in the upper 80s to lower 90s. Overnight lows during this time will be in the mid 60s to near 70 degrees. PoPs were removed over the weekend as the main upper-level trough is expected to be to our east by Saturday. Temperatures are expected to remain near climatology. There remain some differences in the synoptic pattern, the most notable of which is the tropical system generated early next week in the western Gulf by the ECMWF. At the same time, the GFS creates no such system and maintains a weak cut-off upper-low over the Red River. Will continue to monitor the model trends at this time, keeping a dry forecast over the weekend. Johnson && .PRELIMINARY POINT TEMPS/POPS... Abilene 99 76 98 73 / 0 0 5 30 San Angelo 100 75 100 74 / 0 0 0 10 Junction 98 74 97 75 / 0 0 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ 04/25
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 249 PM CDT MON SEP 7 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WEAK COLD FRONT DROPPING SOUTHEAST FROM THE BAY OF GREEN BAY TO WAUTOMA EARLY THIS AFTERNOON. AHEAD OF THE FRONT...CLOUDS ARE FAIRLY WIDESPREAD WITH SCT SHOWERS DEVELOPING OVER THE PAST HOUR OVER THE NORTHERN FOX VALLEY. LOOK FOR THESE SHOWERS TO CONTINUE TO DEVELOP AHEAD OF THE FRONT OVER THE NEXT FEW HOURS. BEHIND THE FRONT...MORE BREAKS IN THE CLOUDS EXIST...BUT THE AIRMASS REMAINS RELATIVELY HUMID UNTIL BEHIND A SECONDARY FRONT OVER FAR NORTHWEST WISCONSIN AND CENTRAL MINNESOTA. AS A SHORTWAVE OVER COLORADO MOVES NORTHEAST TONIGHT...SHOWER AND THUNDERSTORMS CHANCES AS WELL AS POTENTIAL FOR HEAVY RAINFALL ARE THE MAIN FORECAST CONCERNS. TONIGHT...THE SURFACE COLD FRONT WILL SAG INTO SOUTHERN WISCONSIN THIS EVENING. WEAK SHORTWAVE ENERGY EMANATING OUT OF COLORADO WILL LIFT NORTHEAST TONIGHT AND MOVE INTO THE WESTERN GREAT LAKES AFTER MIDNIGHT. MID-LEVEL FLOW WILL BACK AHEAD OF THE SHORTWAVE CAUSING AIR TO RISE OVER THE STALLED BOUNDARY. MODELS HAVE BACKED OFF RAIN CHANCES WITH THEIR 12Z RUNS HOWEVER...SO WILL FOLLOW SUIT BY KEEPING ONLY VERY LOW CHANCES OVER THE FAR SOUTHERN CWA THROUGH THE EVENING AND ONLY RAMP UP PRECIP CHANCES INTO THE LOW LIKELY RANGE OVER EAST- CENTRAL WI AFTER 09Z. WINDS WILL SHIFT TO THE NORTHEAST BRIEFLY THIS EVENING WHICH WILL PROMOTE SOME DRIER AIR FILTERING IN TO N-C WISCONSIN. AS WINDS SHIFT AROUND TO THE SOUTHEAST...MORE OF THE MOIST/TROPICAL AIR WILL GET RECYCLED WESTWARD...WHICH MAY CREATE FOG ISSUES IN THIS AREA. HOWEVER...MID AND HIGH CLOUDS WILL BE ARRIVING BY 06Z...SO WHILE LOWER VSBYS ARE LIKELY...THE PROBABILITY FOR WIDESPREAD DENSE FOG SEEMS PRETTY LOW. WILL KEEP A PATCHY MENTION IN THE FORECAST. LOWS RANGING FROM THE MID 50S NORTH TO MID 60S SOUTH. TUESDAY...THE SHORTWAVE WILL CONTINUE TO QUICKLY ADVANCE NE INTO LOWER MICHIGAN BY 18Z BUT A WEAK SURFACE LOW TRAVELLING ALONG THE STALLED BOUNDARY MAY NOT REACH CENTRAL LAKE MICHIGAN UNTIL 18Z. WEAK MID-LEVEL FGEN NORTH OF THE LOW IN CONCERT WITH UPPER DIVERGENCE SHOULD CREATE AN AREA OF RAIN WITH EMBEDDED TSTORMS OVER CENTRAL AND NORTHEAST WI DURING THE MORNING...WHICH WILL EXIT IN THE AFTERNOON. PWATS WILL REMAIN NEAR 2.0...SO LOCALLY AMOUNTS OF RAIN UP TO AN INCH LOOK POSSIBLE...MAINLY OVER EAST-CENTRAL WI. BUT IT LOOKS LIKE THIS POSSIBILITY WILL BE TO THE EAST OF THE DRENCH AREAS OF CENTRAL WI. SO DO NOT SEE A NEED FOR A FLASH FLOOD WATCH AT THIS TIME. CLOUDY WITH HIGHS IN THE LOW TO MID 70S. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 249 PM CDT MON SEP 7 2015 DRIER AND COOLER AIR WILL RETURN TO THE REGION WEDNESDAY AND WEDNESDAY NIGHT AS WEAK SURFACE RIDGING ARRIVES FROM THE PLAINS STATES. A SHARP UPPER TROUGH DIVING SOUTHEAST FROM CANADA SHOULD INDUCE A WAVE ALONG A COLD FRONT THAT WILL MOVE ACROSS THE AREA THURSDAY AND THURSDAY NIGHT. CYCLONIC UPPER FLOW MAY KEEP THE SHOWERS GOING FRIDAY. DRY...SEASONABLE WEATHER IS EXPECTED SATURDAY AND SUNDAY AS THE UPPER TROUGH EXITS AND SURFACE HIGH BUILDS IN. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1204 PM CDT MON SEP 7 2015 A COLD FRONT WILL BE MOVING ACROSS THE AREA THIS AFTERNOON. ANY SHOWERS OR STORMS ARE EXPECTED TO BE TOO ISOLATED TO INCLUDE IN THE TAFS. CLEARING SKIES SHOULD MOVE IN FROM NORTHWEST TO SOUTHEAST THROUGH THE AFTERNOON...THOUGH CLOUDS MAY NEVER DEPART AT MTW. AHEAD OF A LOW PRESSURE SYSTEM...CIGS/VSBYS ARE EXPECTED TO FALL AGAIN TONIGHT WITH A CHANCE OF RAIN MOVING IN LATE. BEST CHANCES OF RAIN WILL OCCUR OVER CENTRAL AND EAST-CENTRAL WI. WIDESPREAD IFR CONDITIONS ARE LIKELY...POSSIBLY LOWER WITHIN THE RAIN. SOME MARGINAL IMPROVEMENT IS POSSIBLE BY THE END OF THE TAF PERIOD. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......RDM AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1158 PM CDT SUN SEP 6 2015 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 249 PM CDT SUN SEP 6 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD FRONT RUNNING SOUTHWEST FROM NORTHERN MINNESOTA TO EASTERN SOUTH DAKOTA EARLY THIS AFTERNOON. DESPITE ML CAPES UPWARDS OF 2000 J/KG OVER CENTRAL MINNESOTA...THE FRONT IS MOSTLY INACTIVE AS A RESULT OF CIN GREATER THAN 100 J/KG. STILL RATHER UNCERTAIN HOW CONVECTION WILL EVOLVE LATER THIS AFTERNOON. MOST MESOMODELS SHOW CONVECTION DEVELOPING AFTER 21Z...BUT THIS WILL BE AROUND THE SAME TIME AS THE RIGHT FRONT QUAD OF A JET STREAK MOVES OVERHEAD. AS A RESULT...THINK CONVECTION WILL NOT BE AS ROBUST AS THE ARW/NMM...AND MORE ISOLATED TO SCATTERED LIKE THE HRRR. OTHERWISE...THE MID-LEVEL THETAE AND PWAT PLUME WILL CONTINUE TO PUSH IN SCATTERED LIGHT SHOWERS AND ISOLATED TSTORMS FOR THE REST OF THE AFTERNOON INTO CENTRAL AND N-C WISCONSIN. TEMPS MAY NOT GET TO THEIR EARLIER FORECAST HIGHS IN THESE AREAS AS A RESULT. AS THE COLD FRONT MOVES EAST TONIGHT...THUNDERSTORMS CHANCES AND IMPACTS ARE THE MAIN FORECAST CONCERNS. TONIGHT...THE COLD FRONT WILL MOVE EAST TONIGHT...REACHING N-C WISCONSIN BY 06Z AND NORTHEAST WISCONSIN BY 12Z. AT LEAST SCT CONVECTION STILL LOOKS TO FIRE OVER MINNESOTA...BUT THINK IT WILL REMAIN RATHER UNORGANIZED TO THE LARGE CIN AND UPPER LEVEL SUBSIDENCE. BUT AS THE FRONT DRAWS CLOSER TO THE PWAT PLUME OVER WESTERN WISCONSIN...THE ECMWF/GFS/GEM ALL DEVELOP WIDESREAD SHOWERS AND STORMS AFTER 00Z. ALONG WITH PWATS GREATER THAN 2.0 INCHES...ELEVATED INSTABILITY WILL REACH 1000-2000 J/KG WITH LITTLE TO NO CIN. SO WENT WITH THIS IDEA IN THE FORECAST...INCREASING PRECIP CHANCES QUICKLY IN THE 00-03Z TIME PERIOD. PRECIP IS EXPECTED TO WEAKEN SOME BY THE TIME IT REACHES THE LAKE MICHIGAN SHORELINE LATE TONIGHT. SINCE EFFECTIVE BULK SHEARS WILL GENERALLY BE UNDER 20 KTS BY THE TIME CONVECTION DEVELOPS...THINK ANY SEVERE THREAT IS RATHER LOW. ISOLATED STRONG GUSTY WINDS STILL APPEAR REASONABLE...ALONG WITH LOCALLY HEAVY RAINFALL. MONDAY...THE FRONT WILL STILL BE BISECTING THE FORECAST AREA FROM NE WI TO CENTRAL WI AT THE START OF THE MORNING. SCT SHOWERS AND STORMS WILL BE POSSIBLE ALONG THE FRONT OVER CENTRAL AND FAR NE WISCONSIN DURING THE MORNING...AND EAST-CENTRAL WI THROUGH LATE AFTERNOON. CLOUD COVER SHOULD BE WIDESPREAD AHEAD OF THE FRONT...BUT IF CLOUDS DO BREAK FOR A PERIOD...INSTABILITY OVER EAST- CENTRAL WI COULD BECOME SUFFICIENT FOR STRONG STORMS TO DEVELOP. SEVERE STORMS ARE UNLIKELY GIVEN THE POOR SHEAR OF 15-20KTS. BEHIND THE FRONT...N-C WI SHOULD SEE CLEARING TAKE PLACE IN THE AFTERNOON AFTER A CLOUDY START. COOLER HIGHS IN THE MID 70S TO LOW 80S. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 249 PM CDT SUN SEP 6 2015 THE COLD FRONT WILL MAKE IT INTO SOUTHERN WISCONSIN OR NORTHERN ILLINOIS MONDAY NIGHT BEFORE RETURNING NORTHWARD AS A WAVE MOVES NORTHEAST ALONG THE FRONT. THE FRONT WILL BE SHALLOW SO THERE WILL LIKELY BE OVERRUNNING SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHEAST HALF OF THE FORECAST AREA TUESDAY. THE FRONT SHOULD MOVE FAR ENOUGH SOUTH WEDNESDAY FOR DRIER AIR TO RETURN FOR AWHILE. IT WILL ALSO BE COOLER AND LESS HUMID. AN UPPER TROUGH WILL MOVE ACROSS THE REGION THURSDAY AND BRING A CHANCE OF SHOWERS FOLLOWED BY NORTHWEST UPPER FLOW AND MUCH COOLER AND DRIER AIR FOR THE REMAINDER OF THE WEEK. LOWS IN THE 30S ARE POSSIBLE IN FAR NORTHERN WISCONSIN FRIDAY NIGHT. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1155 PM CDT SUN SEP 6 2015 SHOWERS AND EMBEDDED TSTMS WILL CONTINUE TO MOVE THROUGH THE REGION OVERNIGHT...WITH POCKETS OF HEAVY RAINFALL...AND ASSOCIATED MVFR/IFR CONDITIONS. PATCHY LOW CLOUDS (POSSIBLE IFR/LIFR) MAY ALSO ACCOMPANY THE FRONTAL PASSAGE AND LINGER INTO MONDAY MORNING BEFORE ERODING/LIFTING. CONDITIONS SHOULD IMPROVE TO VFR AT MOST LOCATIONS BY EARLY MONDAY AFTERNOON. KEPT LLWS IN THE GRB/ATW/MTW TAFS FOR THE FIRST FEW HOURS OF THE TAF PERIOD...WITH WSW WINDS AROUND 35 KTS AROUND 1000 FT AGL. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......RDM AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1135 AM MDT MON SEP 7 2015 .UPDATE... ISSUED AT 950 AM MDT MON SEP 7 2015 LATEST GUIDANCE SHOWING SOME PRETTY HIGH CAPE OUT OVER THE SOUTHERN NEBRASKA PANHANDLE ALONG AND SOUTH OF AN ALLIANCE TO CHEYENNE LINE THIS AFTERNOON. SPC HRRR SIMULATED RADAR SHOWING QUITE A BIT OF CONVECTION OUT IN THIS AREA THIS AFTERNOON AND EARLY EVENING. WENT AHEAD AND UPPED POPS FOR THIS AREA THIS AFTERNOON/EARLY EVENING. UPDATES HAVE BEEN SENT. AS FOR THE CURRENT RFW...LOOKS TO BE IN PRETTY GOOD SHAPE. POOR OVERNIGHT RH RECOVERIES FOR 301 AND 302...SO WE ARE STARTING OFF PRETTY LOW ALREADY THIS MORNING. NAM SOUNDINGS SHOWING 35-40KTS OF WIND POSSIBLY MIXING DOWN TO THE SURFACE THIS AFTERNOON. WILL KEEP CURRENT HEADLINES AS THEY ARE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 415 AM MDT MON SEP 7 2015 PREDAWN WATER VAPOR IMAGERY SHOWED A UPPER LOW SITUATED OVER CENTRAL SASKATCHEWAN WITH A TROUGH AXIS THROUGH THE NORTHERN ROCKIES AND GREAT BASIN. UPPER RIDGE EXTENDED FROM NORTHERN MX TO THE MIDWEST. THE REGIONAL SURFACE ANALYSIS PLACED A COLD FRONT FROM LAKE SUPERIOR THROUGH CENTRAL IA AND KS THEN NORTH ALONG THE CO FRONT RANGE AND WEST THROUGH CENTRAL UT. A WEAK TROUGH WAS LOCATED NEAR THE LARAMIE RANGE. WIDELY SCATTERED CONVECTION DEVELOPED IN THE VICINITY OF THESE BOUNDARIES... AIDED BY LIFT FROM RIGHT REAR QUADRANT OF UPPER LEVEL JET. REGIONAL RADARS DETECTED SHOWERS AND ISOLATED TSTORMS MOVING NORTHEAST ACROSS WESTERN NE AS WELL AS FROM NORTHWEST CO INTO SOUTH CENTRAL WY. THERE IS GOOD AGREEMENT WITH THE 00Z SHORT RANGE MODEL GUIDANCE PROGGING THE UPPER TROUGH AXIS TO THE WEST TO TRANSLATE EAST DURING THE NEXT 24 HOURS. THE RIGHT REAR QUADRANT OF THE UPPER JET WILL REMAIN OVER THE CWA THROUGH TONIGHT. THIS FEATURE ALONG WITH A COOL FRONT DROPPING SOUTHEAST THROUGH THE PLAINS LATE TODAY WILL TRIGGER WIDELY SCATTERED AFTERNOON AND EVENING CONVECTION...MAINLY FROM SOUTHERN LARAMIE RANGE NORTHEAST INTO THE NE PANHANDLE. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH HIGHS IN THE 60S AND 70S WEST TO THE 80S EAST. THERE WILL BE A 30-DEGREE WEST TO EAST DEW POINT GRADIENT THIS AFTERNOON. GUSTY WESTERLY WINDS AND LOW HUMIDITIES WILL INCREASE THE FIRE DANGER OVER PORTIONS OF EAST AND SOUTH CENTRAL WY THIS AFTERNOON. TUESDAY WILL BE 5 TO 10 DEGREES COOLER ACROSS THE PLAINS FOLLOWING THE FRONTAL PASSAGE. THE DRIER AIR MASS WILL SPREAD EAST INTO THE NE PANHANDLE DURING THE DAY. BREEZY WEST WINDS AND LOW HUMIDITIES WILL CREATE NEAR-CRITICAL FIRE WEATHER CONDITIONS WEST OF THE LARAMIE RANGE. THE FLOW ALOFT BECOMES MORE ZONAL WEDNESDAY. IT WILL BE DRY AND BREEZY DURING THE AFTERNOON ALONG AND WEST OF THE LARAMIE RANGE. TEMPERATURES WEDNESDAY WILL WARM ABOUT 5 DEGREES. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM MDT MON SEP 7 2015 WEDNESDAY NIGHT/THURSDAY...FLOW ALOFT REMAINS NORTHWEST. WITH LIMITED LOW AND MID LEVEL MOISTURE...NOT EXPECTING ANY PRECIPITATION. FRIDAY...NEAR THE SAME OR SLIGHTLY WARMER THAN THURSDAY BASED ON THICKNESS AND HEIGHT CHANGES. LOW AND MID LEVEL MOISTURE LOOKS TOO SCANT FOR ANY PRECIPITATION. SATURDAY...SLOW WARMING TREND CONTINUES AS RIDGING ALOFT BECOMES MORE PRONOUNCED OVERHEAD. STILL NOT ENOUGH LOW AND MID LEVEL MOISTURE FOR SHOWER AND THUNDERSTORM FORMATION. SUNDAY...FLOW ALOFT BECOMES ZONAL...INDUCING EVEN WARMER TEMPERATURES. STILL DRY WITH LIMITED CLOUD COVER. && .AVIATION...(FOR THE 18Z TAFS THROUGH TUESDAY MORNING) VFR CONDITIONS WILL PREVAIL ACROSS SOUTHEAST WYOMING AND MOST OF WESTERN NEBRASKA THROUGH TONIGHT. SCATTERED SHOWERS AND ISOLATED THUNDER WILL DEVELOP NEAR OR JUST EAST OF THE SOUTHERN LARAMIE RANGE AND MOVE EAST THROUGH THIS EVENING. BRIEF MVFR VIS ARE POSSIBLE AROUND KCYS AND KSNY BEFORE THE ACTIVITY DISSIPATES BY 03Z. THERE IS A SLIGHT CHANCE OF LOW CIGS AND PATCHY FOG ACROSS THE WESTERN NEBRASKA TERMINALS AND KCYS BY EARLY TUESDAY MORNING. && .FIRE WEATHER... ISSUED AT 310 AM MDT MON SEP 7 2015 CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ONCE AGAIN THIS AFTERNOON FOR PORTIONS OF EAST AND SOUTH CENTRAL WYOMING. WESTERLY WINDS WILL FREQUENTLY GUST FROM 25 TO 35 MPH WITH MINIMUM RELATIVE HUMIDITIES DECREASING TO 10 TO 15 PERCENT. THESE CRITICAL CONDITIONS WILL DEVELOP ACROSS MOST OF ZONE 302...WESTERN PORTIONS OF ZONE 301...AND NORTHERN PORTIONS OF ZONES 303 AND 308. A COOL FRONT WILL MOVE ACROSS THE PLAINS THIS EVENING...WITH SLIGHTLY COOLER TEMPERATURES FOR TUESDAY. THERE IS A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ALONG AND EAST OF THE SOUTHERN LARAMIE RANGE. NEAR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TUESDAY AND WEDNESDAY FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>303-308. NE...NONE. && $$ UPDATE...GCC SHORT TERM...MAJ LONG TERM...RUBIN AVIATION...TJT FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
955 AM MDT MON SEP 7 2015 .UPDATE... ISSUED AT 950 AM MDT MON SEP 7 2015 LATEST GUIDANCE SHOWING SOME PRETTY HIGH CAPE OUT OVER THE SOUTHERN NEBRASKA PANHANDLE ALONG AND SOUTH OF AN ALLIANCE TO CHEYENNE LINE THIS AFTERNOON. SPC HRRR SIMULATED RADAR SHOWING QUITE A BIT OF CONVECTION OUT IN THIS AREA THIS AFTERNOON AND EARLY EVENING. WENT AHEAD AND UPPED POPS FOR THIS AREA THIS AFTERNOON/EARLY EVENING. UPDATES HAVE BEEN SENT. AS FOR THE CURRENT RFW...LOOKS TO BE IN PRETTY GOOD SHAPE. POOR OVERNIGHT RH RECOVERIES FOR 301 AND 302...SO WE ARE STARTING OFF PRETTY LOW ALREADY THIS MORNING. NAM SOUNDINGS SHOWING 35-40KTS OF WIND POSSIBLY MIXING DOWN TO THE SURFACE THIS AFTERNOON. WILL KEEP CURENT HEADLINES AS THEY ARE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 415 AM MDT MON SEP 7 2015 PREDAWN WATER VAPOR IMAGERY SHOWED A UPPER LOW SITUATED OVER CENTRAL SASKATCHEWAN WITH A TROUGH AXIS THROUGH THE NORTHERN ROCKIES AND GREAT BASIN. UPPER RIDGE EXTENDED FROM NORTHERN MX TO THE MIDWEST. THE REGIONAL SURFACE ANALYSIS PLACED A COLD FRONT FROM LAKE SUPERIOR THROUGH CENTRAL IA AND KS THEN NORTH ALONG THE CO FRONT RANGE AND WEST THROUGH CENTRAL UT. A WEAK TROUGH WAS LOCATED NEAR THE LARAMIE RANGE. WIDELY SCATTERED CONVECTION DEVELOPED IN THE VICINITY OF THESE BOUNDARIES... AIDED BY LIFT FROM RIGHT REAR QUADRANT OF UPPER LEVEL JET. REGIONAL RADARS DETECTED SHOWERS AND ISOLATED TSTORMS MOVING NORTHEAST ACROSS WESTERN NE AS WELL AS FROM NORTHWEST CO INTO SOUTH CENTRAL WY. THERE IS GOOD AGREEMENT WITH THE 00Z SHORT RANGE MODEL GUIDANCE PROGGING THE UPPER TROUGH AXIS TO THE WEST TO TRANSLATE EAST DURING THE NEXT 24 HOURS. THE RIGHT REAR QUADRANT OF THE UPPER JET WILL REMAIN OVER THE CWA THROUGH TONIGHT. THIS FEATURE ALONG WITH A COOL FRONT DROPPING SOUTHEAST THROUGH THE PLAINS LATE TODAY WILL TRIGGER WIDELY SCATTERED AFTERNOON AND EVENING CONVECTION...MAINLY FROM SOUTHERN LARAMIE RANGE NORTHEAST INTO THE NE PANHANDLE. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH HIGHS IN THE 60S AND 70S WEST TO THE 80S EAST. THERE WILL BE A 30-DEGREE WEST TO EAST DEW POINT GRADIENT THIS AFTERNOON. GUSTY WESTERLY WINDS AND LOW HUMIDITIES WILL INCREASE THE FIRE DANGER OVER PORTIONS OF EAST AND SOUTH CENTRAL WY THIS AFTERNOON. TUESDAY WILL BE 5 TO 10 DEGREES COOLER ACROSS THE PLAINS FOLLOWING THE FRONTAL PASSAGE. THE DRIER AIR MASS WILL SPREAD EAST INTO THE NE PANHANDLE DURING THE DAY. BREEZY WEST WINDS AND LOW HUMIDITIES WILL CREATE NEAR-CRITICAL FIRE WEATHER CONDITIONS WEST OF THE LARAMIE RANGE. THE FLOW ALOFT BECOMES MORE ZONAL WEDNESDAY. IT WILL BE DRY AND BREEZY DURING THE AFTERNOON ALONG AND WEST OF THE LARAMIE RANGE. TEMPERATURES WEDNESDAY WILL WARM ABOUT 5 DEGREES. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM MDT MON SEP 7 2015 WEDNESDAY NIGHT/THURSDAY...FLOW ALOFT REMAINS NORTHWEST. WITH LIMITED LOW AND MID LEVEL MOISTURE...NOT EXPECTING ANY PRECIPITATION. FRIDAY...NEAR THE SAME OR SLIGHTLY WARMER THAN THURSDAY BASED ON THICKNESS AND HEIGHT CHANGES. LOW AND MID LEVEL MOISTURE LOOKS TOO SCANT FOR ANY PRECIPITATION. SATURDAY...SLOW WARMING TREND CONTINUES AS RIDGING ALOFT BECOMES MORE PRONOUNCED OVERHEAD. STILL NOT ENOUGH LOW AND MID LEVEL MOISTURE FOR SHOWER AND THUNDERSTORM FORMATION. SUNDAY...FLOW ALOFT BECOMES ZONAL...INDUCING EVEN WARMER TEMPERATURES. STILL DRY WITH LIMITED CLOUD COVER. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 325 AM MDT MON SEP 7 2015 VFR. ISOLATED SHOWERS AND THUNDERSTORMS DEVELOP THIS AFTERNOON AND EVENING SOUTH OF A LARAMIE TO ALLIANCE LINE. THE STRONGER STORMS WILL PRODUCE GUSTY AND ERRATIC WIND GUSTS AS WELL AS OCCASIONAL LIGHTNING. && .FIRE WEATHER... ISSUED AT 310 AM MDT MON SEP 7 2015 CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ONCE AGAIN THIS AFTERNOON FOR PORTIONS OF EAST AND SOUTH CENTRAL WYOMING. WESTERLY WINDS WILL FREQUENTLY GUST FROM 25 TO 35 MPH WITH MINIMUM RELATIVE HUMIDITIES DECREASING TO 10 TO 15 PERCENT. THESE CRITICAL CONDITIONS WILL DEVELOP ACROSS MOST OF ZONE 302...WESTERN PORTIONS OF ZONE 301...AND NORTHERN PORTIONS OF ZONES 303 AND 308. A COOL FRONT WILL MOVE ACROSS THE PLAINS THIS EVENING...WITH SLIGHTLY COOLER TEMPERATURES FOR TUESDAY. THERE IS A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ALONG AND EAST OF THE SOUTHERN LARAMIE RANGE. NEAR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TUESDAY AND WEDNESDAY FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>303-308. NE...NONE. && $$ UPDATE...GCC SHORT TERM...MAJ LONG TERM...RUBIN AVIATION...RUBIN FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1247 AM EDT WED SEP 9 2015 .SYNOPSIS... HIGH PRESSURE IN THE ATLANTIC WILL CIRCULATE A MOIST SOUTH FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A WEAK SURFACE TROUGH WILL ALSO BE NEAR THE AREA. THE PATTERN WILL SUPPORT A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY NEAR THE TIMES OF MAXIMUM HEATING. DRIER AIR WILL BEGIN TO FILTER INTO THE REGION BY THE BEGINNING OF NEXT WEEK BEHIND A COLD FRONT THAT WILL PUSH THROUGH OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE SHOWER CHANCE SHOULD REMAIN LOW DURING THE REST OF TONIGHT BECAUSE OF WEAK INSTABILITY. THE HRRR AND RADAR TRENDS SUPPORT JUST ISOLATED COVERAGE. HIGH LOW-LEVEL MOISTURE AND NOCTURNAL COOLING SHOULD LEAD TO STRATUS AND FOG DURING THE EARLY MORNING HOURS. THE TEMPERATURE FORECAST IS ON TRACK. EXPECT LOWS IN THE LOWER 70S. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... MODELS REMAIN IN GOOD AGREEMENT THROUGH THIS TIME PERIOD. UPPER FLOW WILL BE OUT OF THE SOUTHWEST...WITH THE MAIN UPPER TROUGH STILL OFF TO THE WEST OF THE REGION. CENTER OF THE UPPER RIDGE WILL BE OVER SOUTHERN FLORIDA. WITH SOUTH TO SOUTHWESTERLY LOW- LEVEL FLOW EXPECTED TO OCCUR THROUGH THE PERIOD...MOISTURE IS EXPECTED TO CONTINUE TO INCREASE EACH DAY ACROSS THE REGION. AFTERNOON TEMPERATURES WILL CONTINUE TO BE IN THE LOWER 90S FOR MOST AREAS...WITH OVERNIGHT LOWS FALLING INTO THE LOWER 70S. WITH THE MOISTURE INCREASE EXPECT TO SEE SCATTERED SHOWERS AND THUNDERSTORMS ESPECIALLY DURING THE AFTERNOONS. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS WITH PREVIOUS DAYS FORECAST RUNS...THE GFS/ECMWF BEGIN TO DIVERGE WITH THEIR SOLUTIONS THROUGH THE LONGER TERM. BOTH MODELS DIVE AN UPPER TROUGH SOUTHEASTWARD OUT OF THE UPPER PLAINS STATES FRIDAY NIGHT INTO SATURDAY...THEN CREATE A CUTOFF LOW ACROSS THE EASTERN US. IT IS THE DEVELOPMENT AND PLACEMENT OF THIS CUTOFF THAT THE MODELS DISAGREE WITH OVER THE WEEKEND. THE GFS IS FARTHER SOUTH AND WEAKER THAN THE ECMWF...WITH THE ECMWF LIFTING THE LOW QUICKER TOWARDS THE NORTHEAST SUNDAY INTO MONDAY. OBVIOUSLY THE PLACEMENT AND MOVEMENT OF THE UPPER LOW WILL EVENTUALLY HAVE AN AFFECT ON THE FINAL PLACEMENT AND MOVEMENT OF THE EXPECTED COLD FRONT THAT WILL MOVE THROUGH THE REGION THIS WEEKEND. BOTH MODELS HAVE A PREFRONTAL TROUGH ACROSS THE REGION THROUGH SATURDAY. WHATEVER THE FINAL TRACK IS FOR THE UPPER LOW...BOTH MODELS SHOW THE FRONT PUSHING TOWARDS THE COAST SUNDAY...WITH THE ECMWF BEING FASTER WITH THE TRACK. HAVE LEANED A LITTLE MORE TOWARDS A BLEND OF THE TWO MODELS FOR NOW. EXPECTING SHOWERS AND THUNDERSTORMS TO OCCUR EACH AFTERNOON THROUGH SUNDAY...WITH DRYING FINALLY BEGINNING TO PUSH IN SUNDAY NIGHT. THE REGION SHOULD BEGIN TO SEE SOME COOLER TEMPERATURES AND DRYING TO START OFF THE WORK WEEK BEHIND THE COLD FRONTAL PASSAGE. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... ISOLATED SHOWERS CONTINUE JUST OUTSIDE OF THE FORECAST AREA EARLY THIS MORNING BUT CURRENT RADAR TRENDS SHOW NO THREAT AT THE TERMINALS AT THIS TIME. HIGH RESOLUTION MODELS ALL INDICATING IFR/MVFR CONDITIONS DEVELOPING OVERNIGHT. THIS AGREES WITH PERSISTENCE...SO WILL INCLUDE MORNING STRATUS AND/OR FOG IN ALL TAF SITES DURING THE PRE-DAWN HOURS THIS MORNING. COULD SEE ISOLATED SHOWERS OVERNIGHT GIVEN WEAK ISENTROPIC LIFT. CONDITIONS EXPECTED TO IMPROVE TO VFR AROUND MIDDAY TODAY AS SOUTHWEST WINDS INCREASE TO AROUND 5 TO 10 KNOTS. SCATTERED CONVECTION WILL RECONVENE DURING THE AFTERNOON ONCE AGAIN BUT WILL NOT MENTION IN THE TAFS FOR NOW DUE TO LOW CONFIDENCE IN TIMING AND AREAL COVERAGE. .EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 99
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
342 AM CDT WED SEP 9 2015 ...Updated for Long Term... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT WED SEP 9 2015 The main forecast challenge for early this morning is areas of fog, and or stratus and how dense. Moist weak northeasterly upslope flow and with clear skies is allowing for good radiational cooling, and causing areas of ground fog to develop and some stratus. Will carry areas of fog in most areas this morning, but may need a dense fog advisory in places especially near and west of Dodge City where the NAM and the RAP model shows the highest boundary layer relative humidity. The HRRR model also shows patchy dense fog in the Garden City area. After the fog burns off by mid morning, expect clearing skies and highs in the mid 80s. A surface high pressure ridge will move east while a trough of low pressure develops in the lee of the Rockies. Light and variable winds this morning will become southeast to southerly at 10 mph with 10 to 20 mph far west. For tonight, expect mainly clear skies. A few thunderstorms could develop late across the I-70 corridor as a jet streak moves in. Will carry some small chances for rainfall, towards dawn. Overnight lows will be in the lower 60s with light southeast winds becoming south around 8 to 12 mph. .LONG TERM...(Thursday THROUGH Tuesday) ISSUED AT 339 AM CDT WED SEP 9 2015 For Thursday, an upper level shortwave trough in northwest flow aloft will move across western Kansas pushing a cold front to near Hays to Garden City and Elkhart by late afternoon. Ahead of the cold front, warmer and moist south winds of 15 to 25 mph, will push highs to around 90. Most models have thunderstorms developing by afternoon ahead of the cold front, with a possible MCS (Mesoscale Convective Complex) developing near and east of Dodge City by late afternoon and evening. The cold front will continue to push across western Kansas overnight with numerous thunderstorms developing. Some low stratus is also suggested towards dawn behind the cold front. Will carry around 50 percent chances in the afternoon and evening with lesser chances north of Garden City where dewpoints are much lower. Forecast instability is around 2000-3000 J/KG, but the NAM is much higher and with dewpoints in the upper 60s. With 30kt at mid levels and around 50 to 60kt aloft there could be some severe thunderstorms with large hail from quarter to half dollar size, and strong winds over 60 mph. For Friday into next Tuesday, a dry period is forecast. A large upper level trough will continue to dig into the Upper Midwest and Mississippi Valley with much cooler surface high pressure moving into the Plains. Highs on Friday and Saturday will be in the mid to upper 70s. As the upper trough moves away from the region Sunday into Tuesday, a warming trend will move back into the High Plains with highs in the low 80s on Sunday, then mid to upper 80s on Monday and Tuesday. Overnight lows will be in the 50s into Sunday morning, the gradually warm to 60 to 65 degrees on Monday and Tuesday morning. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Wednesday NIGHT) ISSUED AT 1201 AM CDT WED SEP 9 2015 Areas of LIFR conditions with ground fog and some low stratus will prevail through 14-15Z this morning as winds are light northeasterly and moist upslope along with clear skies and excellent radiational cooling. As a dome of surface high pressure moves east, winds shift to light southeasterly with clearing skies after 15Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 85 62 89 60 / 0 10 50 50 GCK 85 61 90 59 / 0 0 30 20 EHA 87 63 91 60 / 10 10 30 30 LBL 86 62 92 61 / 0 10 30 40 HYS 87 61 89 60 / 0 20 30 40 P28 85 63 89 64 / 0 10 20 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Kruse
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
316 AM CDT WED SEP 9 2015 ...Updated for Short Term... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT WED SEP 9 2015 The main forecast challenge for early this morning is areas of fog, and or stratus and how dense. Moist weak northeasterly upslope flow and with clear skies is allowing for good radiational cooling, and causing areas of ground fog to develop and some stratus. Will carry areas of fog in most areas this morning, but may need a dense fog advisory in places especially near and west of Dodge City where the NAM and the RAP model shows the highest boundary layer relative humidity. The HRRR model also shows patchy dense fog in the Garden City area. After the fog burns off by mid morning, expect clearing skies and highs in the mid 80s. A surface high pressure ridge will move east while a trough of low pressure develops in the lee of the Rockies. Light and variable winds this morning will become southeast to southerly at 10 mph with 10 to 20 mph far west. For tonight, expect mainly clear skies. A few thunderstorms could develop late across the I-70 corridor as a jet streak moves in. Will carry some small chances for rainfall, towards dawn. Overnight lows will be in the lower 60s with light southeast winds becoming south around 8 to 12 mph. .LONG TERM...(Wednesday NIGHT THROUGH Tuesday) ISSUED AT 318 PM CDT TUE SEP 8 2015 Some elevated showers and thunderstorms will be possible around central Kansas late Wednesday night as an area of mid level warm advection develops. These should diminish Thursday morning as low level mixing increases. Northwesterly flow aloft will continue on Thursday. Another shortwave trough will drop out of Alberta into the Midwest on Thursday. This will push another cold front south through western Kansas late Thursday afternoon and Thursday night. Ahead of this front, the boundary layer warms up nicely as low level winds take on a slightly downslope component. Have bumped up Thursdays high temperatures 2-4 degrees in most areas. Widely scattered thunderstorms are expected to develop along and ahead of the cold front across western Kansas by mid to late afternoon. The area of storms will gradually shift to the south and east Thursday night and could linger into Friday before ending. Highs on Friday will be quite a bit cooler behind the front. Model guidance suggests highs in the 70s and this may be a little warm depending on how long any post frontal cloud cover lingers over the area. The weekend into early next week should see dry conditions and moderating temperatures as upper level high pressure redevelops and moves east across the central and southern Plains. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Wednesday NIGHT) ISSUED AT 1201 AM CDT WED SEP 9 2015 Areas of LIFR conditions with ground fog and some low stratus will prevail through 14-15Z this morning as winds are light northeasterly and moist upslope along with clear skies and excellent radiational cooling. As a dome of surface high pressure moves east, winds shift to light southeasterly with clearing skies after 15Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 85 62 89 60 / 0 10 50 50 GCK 85 61 90 59 / 0 0 30 20 EHA 87 63 91 60 / 10 10 30 30 LBL 86 62 92 61 / 0 10 30 40 HYS 87 61 89 60 / 0 20 30 40 P28 85 63 89 64 / 0 10 20 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Gerard AVIATION...Kruse
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1139 PM MDT TUE SEP 8 2015 .UPDATE... ISSUED AT 539 PM MDT TUE SEP 8 2015 A FEW THUNDERSTORMS HAVE POPPED UP IN N-S ORIENTED INSTABILITY AXIS ACROSS EASTERN HALF OF CWA. EXPECT CINH TO STEADILY INCREASE OVER THE NEXT 2 HOURS WHICH WILL ULTIMATELY LIMIT THE COVERAGE AND DURATION THROUGH THE EARLY EVENING. SEEMS TO BE A PRETTY SHARP MOISTURE GRADIENT ACROSS THE AREA ATTM WITH DEWPOINTS AROUND 20 DEGREES COOLER IN THE WEST. WITH LIGHT WINDS AND CLEAR SKIES MAY HAVE TO RETHINK LOW TEMPS...AND HAVE ALSO MODIFIED FOG FORECAST A BIT TO REFLECT THIS ORIENTATION. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 222 PM MDT TUE SEP 8 2015 WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW ACROSS CENTRAL ROCKIES AND OVER OUR CWA ON WESTERN EXTENT OF LARGE SCALE TROUGH. AXIS OF SUBSIDENCE IS CURRENTLY IN PLACE AS A SHORTWAVE TROUGH IS MOVING ACROSS CENTRAL KANSAS. AT THE SURFACE HIGH PRESSURE IS BUILDING INTO OUR CWA FROM THE NORTHERN PLAINS WITH A COLD FRONT THAT MOVED THROUGH OUR CWA EARLY THIS MORNING EXTENDING FROM NORTHEAST KANSAS THROUGH SOUTH CENTRAL KANSAS. TONIGHT...DRY CONDITIONS SHOULD PERSIST THROUGH THE OVERNIGHT PERIOD WITH SUBSIDENCE PERSISTING THROUGH MOST OF THE NIGHT...AND DEEP DRY AIR MASS IN PLACE. EARLY IN THE EVENING STEEP LAPSE RATES LEE TROUGH REBUILDS ALONG KS/CO BORDER OVERNIGHT WITH SOUTHERLY FLOW BRINING HIGH BL MOISTURE IN PLACE. TREND IN GUIDANCE HAS BEEN TO TO SHOW BETTER MIXING AND BL RH STAYING UP LIMITING FOG POTENTIAL. NAM AND RAP DO STILL SHOW SOME REDUCED VISIBILITIES AND I FELT COMFORTABLE KEEPING MENTION IN FORECAST FOR NOW. WEDNESDAY...A QUICK MOVING/WEAK SHORTWAVE TROUGH WILL ROTATE THROUGH NW FLOW JUST NORTH OF OUR CWA. DRY LAYER IN PLACE LOWERS OVERALL CONFIDENCE IN COVERAGE...HOWEVER GUIDANCE IS SHOWING INITIATION EITHER UPSTREAM OR ALONG SURFACE TROUGH AND TRACKING EAST ACROSS THE NORTHERN HALF OF OUR CWA. IF A CELL WERE TO DEVELOP ML CAPE VALUES AROUND 2000 J/KG AND EFFECTIVE SHEAR VALUES AROUND 35KT COULD SUPPORT A LIMITED SEVERE THREAT. IM JUST NOT SURE IF ANYTHING WILL EVEN DEVELOP CONSIDERING THE DRY AIR MASS IN PLACE. I KEPT SLIGHT CHANCE POPS IN THE AFTERNOON...COVERING POTENTIAL. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 255 PM MDT TUE SEP 8 2015 SEVERAL SHORT WAVE TROUGHS MOVE ACROSS THE CENTRAL HIGH PLAINS REGION WEDNESDAY NIGHT...THURSDAY NIGHT...AND FRIDAY EVENING. THE UPPER PATTERN BECOMES MORE AMPLIFIED AS THE SHORT WAVE TROUGHS DIVE INTO THE BASE OF THE MAIN UPPER TROUGH POSITIONED OVER THE MISSISSIPPI VALLEY REGION AS THE UPPER RIDGE AMPLIFIES OVER THE WESTERN UNITED STATES THURSDAY THROUGH FRIDAY NIGHT AND TRANSITIONS EASTWARD OVER THE ROCKIES AND HIGH PLAINS SATURDAY NIGHT. WITH A SURFACE TROUGH/FRONTAL BOUNDARY REMAINING IN THE VICINITY OF THE FORECAST AREA THESE SHORT WAVE TROUGHS TRANSITIONING THE REGION WILL HELP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP EACH DAY FROM LATE WEDNESDAY THROUGH EARLY FRIDAY. BY LATE FRIDAY THE FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE REGION AND SURFACE HIGH PRESSURE MOVES INTO THE AREA. TEMPERATURES WILL WARM THROUGH THURSDAY AHEAD OF THE FRONT WITH HIGH TEMPERATURES ONLY EXPECTED TO REACH IN TO THE 70S ON FRIDAY. TEMPERATURES WILL REBOUND QUICKLY THROUGH THE WEEKEND AND INTO NEXT WEEK AS SOUTHERLY NEAR SURFACE FLOW RETURNS AND THE REGION REMAINS UNDER WEAK RIDGING THROUGH THE WEEKEND AS THE UPPER PATTERN UNDERGOES A TRANSITION TO A RIDGE OVER THE EASTERN HALF OF THE UNITED STATES WHILE THE NEXT SIGNIFICANT LONG WAVE TROUGH DEEPENS OVER THE WESTERN UNITES STATES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1136 PM MDT TUE SEP 8 2015 POTENTIAL PERIOD OF IFR VISIBILITIES OVERNIGHT LOOKS ON TRACK AS LIGHT EASTERLY WINDS SLOWLY ADVECTING INCREASING TDS INTO THE AREA...WITH SFC TEMPS BELOW DOWNSTREAM DEWPOINTS IN SEVERAL AREAS. SATELLITE FOG PRODUCT STARTING TO PICK UP ON SOME LOW STRATUS AS WELL WITH HLC SEEING CLOUD HEIGHTS AROUND 2000 FEET. THIS LOOKS RATHER SPOTTY FOR NOW AND PLAN TO KEEP MAIN FOCUS OF TAFS INCREASING THREAT FOR FOG. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...DR LONG TERM...LOCKHART AVIATION...JRM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
250 AM EDT WED SEP 9 2015 .SYNOPSIS... HIGH PRESSURE WILL SLIDE OFF THE MID ATLANTIC COAST TONIGHT THROUGH WEDNESDAY. A COLD FRONT APPROACHES FROM THE NORTHWEST WEDNESDAY...AND SETTLES INTO THE REGION THURSDAY. THE FRONT STALLS OVER NORTH CAROLINA FRIDAY INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... UPDATE...SHOWERS ACROSS INTERIOR NE NC ARE FINALLY TAPERING OFF LATE THIS EVENING AND A LULL IN ACTIVITY IS EXPECTED DURING THE REST OF THE EVENING AND EARLY OVERNIGHT HOURS. PREVIOUS DISCUSSION...PER LATEST RAP GUIDANCE...WEAK VORT MAX LIFTS NEWD OVER ERN VA TONIGHT. HI-RES GUIDANCE INDICATES THE WARM/MOIST AND MODESTLY UNSTABLE AIR MASS MAY PRODUCE SOME ISOLATED SHOWERS OVERNIGHT ACROSS CENTRAL AND ERN VA AS THE VORT LIFTS...ESPECIALLY OVER THE BAY AND ERN SHORE. HOWEVER... CONFIDENCE IS NOT HIGH ATTM...SO WILL LEAVE SLIGHT CHANCE WORDING. A PARTLY CLOUDY SKY AND DISPERSAL WILL LIMIT FOG DEVELOPMENT TONIGHT...BUT WARM/SOUPY AIR MASS SHOULD BE ENOUGH FOR PATCHY FOG IN AREAS THAT RECEIVED RAINFALL EARLIER TODAY. A MILD TONIGHT AHEAD WITH LOWS IN THE LOW 70S. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... UPPER TROUGH DIGS OVER THE GREAT LAKES REGION WEDS AND THU...RESULTING IN HEIGHT FALLS OVER THE MID-ATLANTIC REGION. AN ASSOCIATED COLD FRONT IS EXPECTED TO REACH THE OHIO VALLEY BY WEDS AFTERNOON. LEE/THERMAL TROUGH DEVELOPS OVER THE PIEDMONT IN ADVANCE OF THE FRONT WEDS AFTERNOON. INCREASING SW FLOW WILL ADVECT DEEP LAYERED MOISTURE INTO THE REGION...WITH PWATS PROGGED AOA 2 INCHES (+1 TO +2 STD DEV). WHILE THE MAIN SHEARING VORT ENERGY REMAINS OVER THE OHIO VALLEY...WEAK PERTURBATIONS IN THE SW FLOW WILL PROVIDE SUBTLE FORCING FOR ASCENT OVER THE LOCAL AREA. THETA-E ADVECTION AND DEWPOINTS IN THE LOW 70S WILL RESULT IN BETTER INSTABILITY...WITH MLCAPE ~1500 J/KG. HAVE FAVORED THE PIEDMONT INTO CENTRAL AND EAST CENTRAL VA FOR 30-40 PCT POPS. WARMER TEMPS ALOFT ACROSS THE SE WILL LIMIT OVERALL COVERAGE...SO HAVE CAPPED AT 30 PCT. EFFECTIVE SHEAR PROGGED AROUND 15 TO 20 KT MAY RESULT IN SLIGHT BETTER ORGANIZATION...BUT SEVERE WEATHER IS NOT ANTICIPATED. WARM AND HUMID CONDITIONS PERSIST...WITH HIGHS FORECAST IN THE UPPER 80S TO AROUND 90 (MID 80S ALONG THE COAST). SLIGHT CHANCE TO CHANCE POPS WILL BE MAINTAINED THROUGH WEDNESDAY NIGHT. MILD AGAIN...WITH LOWS IN THE LOW/MID 70S. THE FLOW CONTINUES TO AMPLIFY OVER THE GREAT LAKES AND ERN CONUS THURSDAY AS SHORTWAVE ENERGY REACHES THE MID-ATLANTIC STATES. SFC LOW DEVELOPS ALONG THE FRONT THU MORNING...LIFTING OVER NRN VA INTO THE DELMARVA THU AFTERNOON AND EVENING. EXPECT WIDESPREAD...BENEFICIAL RAINFALL THURSDAY AFTERNOON. A WARM/MOIST AIR MASS REMAINS IN PLACE...BUT INSTABILITY WILL BE LIMITED DUE TO CLOUD COVER AND PRECIP. HAVE RETAINED LIKELY POPS ACROSS ALL BUT THE FAR SE LOCAL AREA. LACK OF ORGANIZED FORCING AND ANOMALOUS FLOW WILL KEEP OVERALL QPF AOB ONE HALF OF AN INCH. WEAK FLOW AND MBE/CORFIDI VECTORS FAVOR LOCALLY HIGHER AMOUNTS. CLOUDS/PRECIP AND HEIGHT/THICKNESS FALLS YIELD TEMPS RANGING FROM THE LOW 80S NW TO UPPER 80S SE. THE FRONT STALLS ALONG THE COAST THU NIGHT AND FRI IN SWLY FLOW ALOFT. BEST MOISTURE AND SHORTWAVE ENERGY LOCATES OVER THE COASTAL PLAIN...AND WILL RETAIN CHANCE POPS ACROSS SOUTHERN VA AND SE VA/NE NC. MORE SEASONABLE CONDITIONS EXPECTED FRI WITH HIGHS IN THE LOW TO MID 80S AND DEWPOINTS COOLING INTO THE LOW 60S NW TO UPPER 60S SE. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MODELS CONT TO STRUGGLE WITH A SOLN TO JUST HOW FAR EAST THE FRNTL BNDRY GETS THIS WEEKEND AS IT APPRCHS THE OFFSHORE RIDGE. CONSENSUS IS THAT IT STALLS RIGHT ALONG THE COAST AS SVRL WAVES OF LOW PRS MOVE NE ALONG IT. IN ADDITION...A RTHR POTENT UPR LVL SYSTM PROGGED TO DIVE SE FROM THE GT LAKE RGN LATER THIS WEEKEND. GFS STILL FRTHER SOUTH...BUT IT IS STARTING TO COME IN LINE WITH THE ECMWF SOLN OF SWING THE UPR LVL LOW NORTH OF FA WITH MOST OF THE ENERGY FROM THE VA MTS ON NORTH. APPEARS HIGH PRS MOVG EAST FROM NATIONS MID SECTION WILL BE STRNG ENUF TO PUSH THE ENTIRE SYSTM OFFSHORE ERLY NEXT WK. GIVEN THE ABOVE UNCERTAINTY...WILL KEEP A CONSISTENT FCST AND LEAN MORE TOWARD A ECMWF SOLN. KEPT CHC POPS FRI NITE THRU SUN NITE (HIGHEST POPS ALONG THE COAST AND MENTION THUNDER IN THE IN AFTN AND EVE). DRY MON/TUE. A COOLING TREND THRU THE PRD. HIGHS SAT 80- 85...COOLER AT THE BEACHES. LOWS 60-65. HIGHS SUN/MON 75-80. LOWS M50S-L60S. HIGHS TUE U70S-L80S. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... 06Z TAF PERIOD STARTS OUT WITH VFR CONDS TRANSITIONING TO MVFR/IFR IN SPOTS WITH LIGHT WINDS AND SFC HI PRES IN THE AREA. INCLUDED THIS IN ALL TAFS EXCEPT KORF. CONDS WILL IMPROVE BY MID MORNG EVERYWHERE. THERE WILL BE A CHANCE OF SHRAS/TSTMS FM TDA THRU THE WEEKEND AS A COLD FRNT APPROACHES FM THE W AND STALLS IN THE VICINITY. && .MARINE... NO HEADLINES XPCT AS HIGH PRS MOVES OFFSHORE RESULTING IN A RETURN SLY FLOW THRU THURSDAY. ONCE AGAIN...HIGH RES DATA SUGGESTS SOME CHANNELING UP THE BAY AT NIGHT...SO KEPT SPEEDS AOB 15 KTS FOR NOW. COLD FRONT APPRCHS THE AREA THURSDAY AFTN THEN CROSSES THE WTRS THURSDAY NIGHT BEFORE STALLING JUST OFF THE COAST FRIDAY. LACK OF CAA BEHIND THE FRONT WILL KEEP SUB-SCA CNDTNS INTO FRIDAY. LOCATION OF FRONT INTO THE WEEKEND WILL BE KEY TO THE FCST. RIGHT NOW THE BNDRY LOOKS TO STRADDLE THE COAST KEEPING WNDS IN A GNRL WEST DRCTN AT SPEEDS ARND 10 KTS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ/SAM NEAR TERM...AJZ/BMD/SAM SHORT TERM...AJZ/SAM LONG TERM...MPR AVIATION...MAS MARINE...MPR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
320 AM EDT WED SEP 9 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 417 PM EDT TUE SEP 8 2015 WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A MID/UPPER LEVEL LOW SPINNING OVER MANITOBA. ONE SHORTWAVE IS LIFTING NE ACROSS NRN ONTARIO TO THE N OF LAKE OF THE WOODS. TAIL END OF THAT WAVE IS GENERATING SHRA/TSRA N OF THE MN/ONTARIO BORDER. CLOSER TO HOME... SHORTWAVE THAT LIFTED ACROSS WI TOWARD ERN UPPER MI BROUGHT WIDESPREAD SHRA/ISOLD TSTMS ACROSS ALL BUT FAR WRN UPPER MI TODAY. THAT ACTIVITY IS MOVING OUT QUICKLY NOW. TO THE W...IT APPEARS THAT THERE ARE 2 BOUNDARIES THAT STILL NEED TO BE WATCHED FOR NEW CONVECTIVE DEVELOPMENT. THE FIRST IS LAKE BREEZE BOUNDARY RUNNING FROM THE E SIDE OF THE KEWEENAW TO CNTRL GOGEBIC COUNTY...AND THE OTHER IS THE COLD FRONT MOVING ACROSS THE WRN PART OF LAKE SUPERIOR. MOSTLY FOLLOWED RECENT RADAR TRENDS TO MOVE LINGERING WIDESPREAD SHRA OUT OF THE ERN FCST AREA OVER THE NEXT FEW HRS. HELD LOW POPS BACK TO THE W AHEAD OF THE TWO AFOREMENTIONED BOUNDARIES. LATEST SPC MESOANALYSIS HAS MLCAPES UP TO AROUND 250J/KG OR SO AND SBCAPE TO AROUND 500J/KG AHEAD OF THE BOUNDARIES. WITH CU BUILDING UP PER VIS SATELLITE IMAGERY...CAN`T RULE OUT ISOLD/SCT SHRA DEVELOPMENT... PERHAPS A TSTM. WHATEVER HAPPENS...PCPN RISK WILL BE DONE BY LATE EVENING AS COLD FRONT SWEEPS ACROSS THE AREA. MUCH DRIER AIR MASS SURGING INTO THE AREA WILL FINALLY BRING AN END TO THE UNSEASONABLY LONG STRETCH OF HIGH DWPTS FOR THIS TIME OF YEAR. UPSTREAM IN NRN MN...SFC DWPTS HAVE FALLEN THRU THE 40S WITH EVEN SOME 30S SHOWING UP. EXPECT CLEARING SKIES FROM THE W TONIGHT. IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL AFFECT THE ERN SHORELINE AREAS BEFORE BEING SWEPT CLEAR BY THE MUCH DRIER AIR MASS. IT WILL BE THE COOLEST NIGHT IN WELL OVER A WEEK. MIN TEMPS SHOULD FALL INTO THE MID 40S OVER THE INTERIOR W HALF AND MOSTLY LOW/MID 50S ELSEWHERE. DRY AIR MASS WILL SET UP A NICE WED UNDER PLENTY OF SUNSHINE. DWPTS WILL BE LOW...MOSTLY IN THE 40S...WITH HIGH TEMPS IN THE UPPER 60S TO MID 70S...WARMEST IN THE AREAS THAT SEE DOWNSLOPING UNDER A WESTERLY WIND. SPEAKING OF WHICH...WINDS SHOULD BE GUSTY INTO THE 20 TO 30 MPH RANGE...ESPECIALLY OVER THE NW FCST AREA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 320 AM EDT WED SEP 9 2015 NAM SHOWS A BROAD 500MB TROUGH OVER THE UPPER GREAT LAKES AND EASTERN U.S. WITH A RIDGE IN THE WESTERN U.S. THIS TROUGH DEEPENS WITH TIME AND THE TROUGH AXIS MOVES ACROSS THE UPPER GREAT LAKES ON FRI. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE MOVING ACROSS THE AREA ON THU WITH DEEPER MOISTURE ACROSS THE SOUTHERN HALF OF THE CWA. LAKE EFFECT COMES INTO PLAY THIS FORECAST PERIOD AS OPEN LAKE TEMPERATURES RANGE FROM 12C TO 15C AND 850 MB TEMPERATURES DROP TO 2C TO 4C THU NIGHT AND FRI AND THIS IS ENOUGH DELTA-T COMBINED WITH SOME WEAK 850-500 MB Q-VECTOR CONVERGENCE TO AT LEAST KEEP IN SLIGHT CHANCE TO LOW CHANCE POPS THU NIGHT AND FRI AND ALSO A BIT MORE CLOUD COVER DUE TO LAKE EFFECT CLOUDS. FOR THU...KEPT HIGHEST POPS IN THE SOUTH WITH BEST MOISTURE IN THAT AREA AND DRY IN THE FAR NORTHERN CWA. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST OR FOR TEMPERATURES. IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE UPPER GREAT LAKES EMBEDDED IN A DEEP TROUGH OVER THE EASTERN U.S. 12Z SAT WITH A RIDGE OVER THE WESTERN U.S. THIS TROUGH MOVES SLOWLY EAST 12Z SUN WITH THE RIDGE OVER THE WESTERN U.S. GETTING FLATTENED WITH TIME. BY 12Z MON...RIDGE IS FLATTENED ENOUGH TO CAUSE ZONAL FLOW OVER THE UPPER GREAT LAKES MON. A TROUGH MOVES ONTO THE WEST COAST 12Z TUE WITH ZONAL FLOW CONTINUING OVER THE UPPER GREAT LAKES ON TUE. TEMPERATURES WILL STAY ABOVE NORMAL THIS FORECAST PERIOD AND WILL GO DRY SAT THROUGH SUN NIGHT AND THEN A WEAK COLD FRONT STALLS OUT OVER THE AREA FOR MON INTO TUE WITH LIMITED MOISTURE AVAILABLE TO WORK WITH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 119 AM EDT WED SEP 9 2015 EXPECT VFR CONDITIONS THROUGH WEDNESDAY. MID CLOUDS INCREASE ON WEDNESDAY EVENING WITH SOME RAIN POSSIBLE LATER WEDNESDAY NIGHT. GUSTY WINDS ARE EXPECTED AT ALL THE TAF SITES ON WEDNESDAY DURING PEAK MIXING OF THE DAY. STRONGEST WIND GUSTS OVER 25 KTS WILL BE AT THE MORE EXPOSED KCMX LOCATION. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 417 PM EDT TUE SEP 8 2015 FIRST UP...IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL BE SWEPT OFF THE ERN PORTION OF THE LAKE TONIGHT AS STRENGTHENING W WINDS BEHIND A PASSING COLD FRONT USHER IN A MUCH DRIER AIR MASS TONIGHT. INCOMING PRES RISES WILL HELP BOOST W WIND GUSTS TO 25-30KT FOR A TIME AFTER FRONTAL PASSAGE. DURING WED...W WINDS OF 15-25KT WILL GENERALLY BE THE RULE...BUT OVER CNTRL LAKE SUPERIOR AND IN PARTICULAR AROUND THE TIP OF THE KEWEENAW PENINSULA...WINDS OF 20- 30KT ARE EXPECTED. LIGHTER WINDS OF 10-20KT ARE EXPECTED FOR WED NIGHT/THU. ARRIVAL OF A COLDER AIR MASS AHEAD OF APPROACHING SFC HIGH PRES WILL LEAD TO A PERIOD OF STRONGER WINDS OF 15-30KT AGAIN THU NIGHT INTO AT LEAST FRI MORNING...STRONGEST OVER THE E HALF. WINDS WILL SLOWLY DIMINISH W TO E FRI AFTN THRU SAT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...07 AVIATION...JLA MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
119 AM EDT WED SEP 9 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 417 PM EDT TUE SEP 8 2015 WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A MID/UPPER LEVEL LOW SPINNING OVER MANITOBA. ONE SHORTWAVE IS LIFTING NE ACROSS NRN ONTARIO TO THE N OF LAKE OF THE WOODS. TAIL END OF THAT WAVE IS GENERATING SHRA/TSRA N OF THE MN/ONTARIO BORDER. CLOSER TO HOME... SHORTWAVE THAT LIFTED ACROSS WI TOWARD ERN UPPER MI BROUGHT WIDESPREAD SHRA/ISOLD TSTMS ACROSS ALL BUT FAR WRN UPPER MI TODAY. THAT ACTIVITY IS MOVING OUT QUICKLY NOW. TO THE W...IT APPEARS THAT THERE ARE 2 BOUNDARIES THAT STILL NEED TO BE WATCHED FOR NEW CONVECTIVE DEVELOPMENT. THE FIRST IS LAKE BREEZE BOUNDARY RUNNING FROM THE E SIDE OF THE KEWEENAW TO CNTRL GOGEBIC COUNTY...AND THE OTHER IS THE COLD FRONT MOVING ACROSS THE WRN PART OF LAKE SUPERIOR. MOSTLY FOLLOWED RECENT RADAR TRENDS TO MOVE LINGERING WIDESPREAD SHRA OUT OF THE ERN FCST AREA OVER THE NEXT FEW HRS. HELD LOW POPS BACK TO THE W AHEAD OF THE TWO AFOREMENTIONED BOUNDARIES. LATEST SPC MESOANALYSIS HAS MLCAPES UP TO AROUND 250J/KG OR SO AND SBCAPE TO AROUND 500J/KG AHEAD OF THE BOUNDARIES. WITH CU BUILDING UP PER VIS SATELLITE IMAGERY...CAN`T RULE OUT ISOLD/SCT SHRA DEVELOPMENT... PERHAPS A TSTM. WHATEVER HAPPENS...PCPN RISK WILL BE DONE BY LATE EVENING AS COLD FRONT SWEEPS ACROSS THE AREA. MUCH DRIER AIR MASS SURGING INTO THE AREA WILL FINALLY BRING AN END TO THE UNSEASONABLY LONG STRETCH OF HIGH DWPTS FOR THIS TIME OF YEAR. UPSTREAM IN NRN MN...SFC DWPTS HAVE FALLEN THRU THE 40S WITH EVEN SOME 30S SHOWING UP. EXPECT CLEARING SKIES FROM THE W TONIGHT. IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL AFFECT THE ERN SHORELINE AREAS BEFORE BEING SWEPT CLEAR BY THE MUCH DRIER AIR MASS. IT WILL BE THE COOLEST NIGHT IN WELL OVER A WEEK. MIN TEMPS SHOULD FALL INTO THE MID 40S OVER THE INTERIOR W HALF AND MOSTLY LOW/MID 50S ELSEWHERE. DRY AIR MASS WILL SET UP A NICE WED UNDER PLENTY OF SUNSHINE. DWPTS WILL BE LOW...MOSTLY IN THE 40S...WITH HIGH TEMPS IN THE UPPER 60S TO MID 70S...WARMEST IN THE AREAS THAT SEE DOWNSLOPING UNDER A WESTERLY WIND. SPEAKING OF WHICH...WINDS SHOULD BE GUSTY INTO THE 20 TO 30 MPH RANGE...ESPECIALLY OVER THE NW FCST AREA. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 414 PM EDT TUE SEP 8 2015 THE UPPER TROUGH THAT IS CURRENTLY MOVING EAST ACROSS SOUTH CENTRAL CANADA AND THE UPPER MISSISSIPPI VALLEY WILL MOVE INTO THE UPPER GREAT LAKES OVER THE NEXT 12 HOURS AND THEN AMPLIFY OVER THE REGION HEADING INTO THE END OF THE WORK WEEK AS A WAVE CURRENTLY MOVING INTO BRITISH COLUMBIA ROTATES THROUGH. THIS SETUP WILL LEAD TO GENERALLY BELOW NORMAL TEMPERATURES INTO THE START OF THE WEEKEND WITH PERIODS OF SHOWERS. AFTER A DRY START TO THE LONG TERM PERIOD ON WEDNESDAY EVENING (DUE TO AN EXISTING HIGH PRESSURE RIDGE)...A WEAK SURFACE TROUGH WILL MOVE EAST ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE GREAT LAKES REGION LATER WEDNESDAY NIGHT AND THURSDAY. THIS WILL BE IN RESPONSE TO THE SHORTWAVE CURRENTLY MOVING INTO BRITISH COLUMBIA THAT WILL BE ROUNDING THE BASE OF THE UPPER TROUGH. SHOWERS ARE EXPECTED TO DEVELOP IN SOUTHERN MINNESOTA AND WESTERN WISCONSIN ON WEDNESDAY NIGHT AND THEN SPREADING EAST-NORTHEAST INTO PORTIONS OF UPPER MICHIGAN. MODELS ARE DIFFERING ON THE NORTHWEST EXTENT OF THE SHOWERS...LARGELY DUE TO THE TRACK OF THE SHORTWAVE WITH HALF TRACKING IT ACROSS NORTHERN WISCONSIN (PUSHING PRECIP FARTHER NORTH) AND THE OTHER HALF TRACK IT MORE ACROSS SOUTHERN WISCONSIN (AND HAS PRECIP ONLY BRUSHING THE SOUTHERN THIRD OF THE AREA) ON THURSDAY. DID SEE A SOUTHEAST TREND WITH THE 12Z ECMWF...WHICH IS MORE IN LINE WITH THE 12Z GFS/GEM...SO WHILE CONFIDENCE IS LOW...FELT IT WAS REASONABLE TO TREND THE CHANCE POPS FARTHER TO THE SOUTHEAST AND MORE OVER THE SOUTH CENTRAL AND ALONG THE LAKE MICHIGAN SHORELINE. THOSE SHOWERS WILL DEPART ON THURSDAY NIGHT AS THE SHORTWAVE AND SURFACE TROUGH DEPARTS. THIS WILL ALLOW MUCH COLDER AIR TO SURGE SOUTH ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY...WITH 850MB TEMPS FALLING TO 1-2C. SINCE LAKE SUPERIOR TEMPERATURES ARE IN THE 12-18C RANGE...EXPECT SOME POTENTIAL OF LAKE EFFECT/ENHANCED RAIN FOR THURSDAY NIGHT INTO FRIDAY. MODELS SHOWING DECENT MOISTURE BELOW THE INVERSION AROUND 750MB...SO HAVE CHANCE POPS FOR THE FAVORED NORTHERLY WIND LOCATIONS NEAR LAKE SUPERIOR DURING THAT TIME. WILL LIKELY NEED TO TREND POPS UP FURTHER IF THE LATEST MODEL TRENDS CONTINUE. IN ADDITION...THAT COLD AIR AND DECENT CLOUD COVER FOR MUCH OF THE DAY ON FRIDAY WILL KEEP HIGHS IN THE 50S. A SURFACE HIGH OFF TO THE WEST IN THE DAKOTAS WILL TRY TO PUSH A SURFACE RIDGE INTO THE AREA ON FRIDAY...BUT IT WILL LIKELY REALLY ARRIVE ON SATURDAY AS THE UPPER TROUGH BEGINS TO SHIFT EAST. DRIER AIR ASSOCIATED WITH THE HIGH WILL LEAD TO DECREASING CLOUDS FROM WEST TO EAST ON FRIDAY AFTERNOON...WITH CLEAR SKIES REMAINING IN PLACE THROUGH MUCH OF THE WEEKEND. SATURDAY WILL REMAIN BELOW NORMAL FOR HIGHS...BUT WITH THE UPPER RIDGE AXIS SHIFTING EAST FROM THE DAKOTAS AND INTO THE UPPER GREAT LAKES REGION FOR SUNDAY AND MONDAY...EXPECT HIGHS TO RISE BACK UP TO NORMAL OR EVEN SLIGHTLY ABOVE NORMAL VALUES. WILL NEED TO WATCH THE EVOLUTION OF THE UPPER TROUGH JUST TO THE EAST-SOUTHEAST OF THE AREA FOR SUNDAY/MONDAY TIME FRAME...AS THERE ARE SOME HINTS OF IT ROTATING BACK NORTHWEST AS THE UPPER RIDGE REMAINS FARTHER WEST. THAT WOULD LEAD TO COOLER AND BETTER OPPORTUNITIES FOR RAIN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 119 AM EDT WED SEP 9 2015 EXPECT VFR CONDITIONS THROUGH WEDNESDAY. MID CLOUDS INCREASE ON WEDNESDAY EVENING WITH SOME RAIN POSSIBLE LATER WEDNESDAY NIGHT. GUSTY WINDS ARE EXPECTED AT ALL THE TAF SITES ON WEDNESDAY DURING PEAK MIXING OF THE DAY. STRONGEST WIND GUSTS OVER 25 KTS WILL BE AT THE MORE EXPOSED KCMX LOCATION. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 417 PM EDT TUE SEP 8 2015 FIRST UP...IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL BE SWEPT OFF THE ERN PORTION OF THE LAKE TONIGHT AS STRENGTHENING W WINDS BEHIND A PASSING COLD FRONT USHER IN A MUCH DRIER AIR MASS TONIGHT. INCOMING PRES RISES WILL HELP BOOST W WIND GUSTS TO 25-30KT FOR A TIME AFTER FRONTAL PASSAGE. DURING WED...W WINDS OF 15-25KT WILL GENERALLY BE THE RULE...BUT OVER CNTRL LAKE SUPERIOR AND IN PARTICULAR AROUND THE TIP OF THE KEWEENAW PENINSULA...WINDS OF 20- 30KT ARE EXPECTED. LIGHTER WINDS OF 10-20KT ARE EXPECTED FOR WED NIGHT/THU. ARRIVAL OF A COLDER AIR MASS AHEAD OF APPROACHING SFC HIGH PRES WILL LEAD TO A PERIOD OF STRONGER WINDS OF 15-30KT AGAIN THU NIGHT INTO AT LEAST FRI MORNING...STRONGEST OVER THE E HALF. WINDS WILL SLOWLY DIMINISH W TO E FRI AFTN THRU SAT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...JLA MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1202 AM CDT WED SEP 9 2015 .UPDATE: Issued at 850 PM CDT Tue Sep 8 2015 Have updated forecast to pull precip further S as cdfnt continues to slowly move swd. Precip along the fnt shud fill in a little more to the E over night. Overall, have trended twd the RAP soln which keeps most of the precip across sern portions of the CWA by sunrise Wed morning. && .SHORT TERM: (Through Late Tonight) Issued at 210 PM CDT Tue Sep 8 2015 Cold front really struggling to make too much progress south today and is currenlty aligned from near Kansas City to the Quad Cities. Precipitation trends remain the focus for the forecast. Area of showers and thunderstorms continue to slowly progress south on outflow from last nights convection that occurred to our northwest. This is well out ahead of the front and away from any deep layer flow aloft so severe chances have been largely removed. More convection is forming back across central Kansas and think this wave of precipitation will replace ongoing activity overnight and into tomorrow morning. CVKING .LONG TERM: (Wednesday through Next Tuesday) Issued at 210 PM CDT Tue Sep 8 2015 Upper level trof axis, currently extending from the upper Midwest to the central Plains, will move east over the next 24 hours forcing the cold front south through the area and ending the threat of precipiation from northwest to southeast. Temperatures should cool to near normal values Wednesday and Thursday before a stronger cold front arrives Thursday night and Firday. Have some chance PoPs with the front, but think focus may remain west of the CWA. Autumn temperatures arrive for the weekend with highs in the 70s and lows dipping into the upper 40s and lower 50s. CVKING && .AVIATION: (For the 06z TAFs through 06z Wednesday Night) Issued at 1157 PM CDT Tue Sep 8 2015 Cold front is still approaching KCOU, and is south of KUIN. Broken line of SHRA/TSRA continues to fire along it and different waves should continue to develop and dissipate over the next several hours. Low CIGs continue to develop with expanded area of IFR now looking likely for STL metro and back to KCOU and have placed in the 06z TAF issuance for overnight and Wednesday morning. These IFR CIGs will then be slow to pull out, with non-VFR CIGs expected well into the day Wednesday with diurnal enhancements as it becomes more of a broken cumulus cloud field. Eventually clearing is anticipated by Wednesday evening. Winds will be light throughout, becoming northerly behind front. Specifics for KSTL: conditions on their way down with IFR now expected later tonight and to continue into Wednesday morning before gradual improvement, with MVFR CIGs hanging on into the afternoon, with a return to VFR conditions is expected by nightfall Wednesday night. TES && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
324 AM EDT WED SEP 9 2015 .SYNOPSIS... SUMMERLIKE HEAT WILL BE IN PLACE TODAY WITH A FEW STRAY THUNDERSTORMS. CLOUDS AND RAIN CHANCES THEN INCREASE LATE IN THE WEEK WITH THE SLOW APPROACH OF A COLD FRONT. THIS BOUNDARY MAY NOT PUSH THROUGH UNTIL MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM WEDNESDAY...SURFACE HIGH PRESSURE NORTH OF BERMUDA WILL PROVIDE A WARM AND HUMID AIRMASS TO THE CAROLINAS TODAY STRAIGHT OUT OF THE BAHAMAS. 850 MB TEMP EXPECTED TO HOVER AROUND +18C IS NEAR THE 95TH PERCENTILE FOR CLIMATOLOGICAL READINGS THIS TIME OF YEAR AT CHS. AS A RESULT WE SHOULD SEE HIGH TEMPERATURES RISE INTO THE LOWER 90S INLAND WITH UPPER 80S ON THE COAST. THIS IS STILL 5 OR MORE DEGREES AWAY FROM RECORDS. WITH DEWPOINTS REMAINING IN THE LOWER TO MID 70S HEAT INDEX VALUES SHOULD REACH 100 DEGREES ACROSS PARTS OF THE PEE DEE REGION. AN UPPER DISTURBANCE CURRENTLY MOVING NORTHEASTWARD FROM GEORGIA INTO SOUTHERNMOST SOUTH CAROLINA IS HELPING SUPPORT A CLUSTER OF THUNDERSTORMS NEAR CHARLESTON. THIS DISTURBANCE SHOULD MOVE ALONG THE SOUTH CAROLINA COAST AFTER SUNRISE...REACHING SE NORTH CAROLINA BY LATE THIS MORNING. HIGH RES MODELS INCLUDING THE NSSL WRF...THE LATEST SEVERAL HRRR RUNS...AND THE ARW AND NMM VERSIONS OF THE WRF ALL SUPPORT THE IDEA OF CONVECTION BECOMING MORE WIDESPREAD ACROSS SE NORTH CAROLINA AROUND 15Z (11 AM) AS THE UPPER DISTURBANCE ENCOUNTERS AN UNCAPPED AIRMASS WITH SURFACE-BASED CAPE IN EXCESS OF 2000 J/KG. I HAVE INCREASED POPS TO 40-60 PERCENT IN THE CAPE FEAR REGION...WITH POPS ELSEWHERE IN THE 10-30 PERCENT RANGE GIVEN PROBABLE SUBSIDENCE AND MID-LEVEL DRYING BEHIND THE UPPER DISTURBANCE. CONVECTION SHOULD TEND TO MOVE NORTHEASTWARD DURING THE MID TO LATE AFTERNOON...FOLLOWING THE DISTURBANCE INTO FAR-EASTERN NORTH CAROLINA. TONIGHT ANOTHER UPPER DISTURBANCE TAKING A MORE INLAND TRACK COULD SPREAD EVENING SHOWERS AND STORMS ACROSS THE I-95 CORRIDOR. I HAVE NOT GONE TOO HIGH WITH POPS HOWEVER GIVEN THE COOLING/STABILIZING BOUNDARY LAYER AND THE BEST LIFT WITH THE DISTURBANCE EXPECTED TO PASS ACROSS CENTRAL AND WESTERN NORTH CAROLINA. AS LOW LEVEL WINDS TURN SOUTHWESTERLY A MODEST LOW LEVEL JET SHOULD DEVELOP WITH 975 MB (1000 FOOT AGL) WINDS INCREASING TO 20-25 KT. THIS SHOULD HELP KEEP A STRONG NOCTURNAL INVERSION FROM DEVELOPING AND LOWS SHOULD ONLY FALL TO 72-75 INLAND AND 75-78 AT THE COAST...ABOUT 7 DEGREES ABOVE NORMAL FOR THE DATE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... PREFRONTAL TROUGH MOVES INTO THE CAROLINAS AND STALLS ON THURSDAY. AHEAD OF THIS FEATURE THERE SHOULD BE AMPLE MOISTURE FOR AT LEAST SCATTERED CONVECTIVE COVERAGE. MID LEVEL FORCING IN THE FORM OF VORT MAXES COME LATE IN THE DAY AND AT NIGHT PREVENTING THE NORMAL DIURNAL DYING OFF OF RADAR COVERAGE EVEN THOUGH DEEP CONVECTION MAY BE HARDER TO COME BY DUE TO THE DECREASE IN INSTABILITY. THIS BOUNDARY WEAKENS AND MOVES OFFSHORE BY FRIDAY AND WAS PREVIOUSLY TO BE REPLACED BY A LEGITIMATE COLD FRONT. THIS FRONT NOW APPEARS SLOWER LEAVING NOT MUCH IN THE WAY OF SURFACE FEATURES IN PLACE LOCALLY. FURTHER COMPLICATING FRIDAY FORECAST IS THE DIFFERENCE IN TIMING AMONGST MODELS WITH RESPECT TO SOME MID LEVEL IMPULSES. IN THE END DID NOT MAKE MUCH CHANGE AND WILL ONCE AGAIN CARRY CHANCE POPS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY... IMPRESSIVELY DEEP UPPER TROUGH DRIVES COLD FRONT INTO THE COASTAL PLAIN ON SATURDAY. BEING ALIGNED WITH THE FLOW ALOFT IT WILL STALL ON SUNDAY. SATURDAY OFFERS THE DEEPEST MOISTURE AND WILL LIKELY PAN OUT BEING A VERY UNSETTLED DAY WITH PERHAPS NUMEROUS SHOWERS AND IF THE DIURNAL TIMING IS RIGHT STRONGER THUNDERSTORMS. MODELS AT SOME ODDS REGARDING THE DEPTH AND TILT OF THE UPPER WAVE AND UNTIL IT ENTERS THE UPPER AIR NETWORK ITS HARD TO SPECULATE WHICH IS CORRECT. ON SUNDAY THE DEEP MOISTURE GETS SHUNTED OFFSHORE BUT SOME LOW LEVEL MOISTURE ALONG THE BOUNDARY WILL STILL CALL FOR SOME LOW RAIN CHANCES MAINLY ALONG THE COAST. COOLER AND DRYER AIR NOW APPEARS TO ARRIVE FASTER AND SHOULD BE ADVECTING IN MODERATELY STRONGLY BY MONDAY. COOLER WEATHER WILL LAST INTO TUESDAY AS THE CENTER OF THE LARGE HIGH BUILDS TO OUR NORTH. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...LOW STRATUS AND FOG IS MOST LIKELY TO OCCUR AT THE INLAND AIRPORTS: FLO AND LBT. THE LATEST HRRR MODEL (WHICH HAS DONE VERY WELL THE PAST SEVERAL NIGHTS) SHOWS LOW CEILINGS INTERMITTENTLY PRESENT AT THESE SITES BETWEEN 08-12Z. CLOSER TO THE COAST THE AIRMASS SHOULD SUPPORT THE DEVELOPMENT OF LOW MARITIME CUMULUS IN A MOIST ONSHORE FLOW BEGINNING 08-09Z...WITH TEMPORARY MVFR CEILINGS POSSIBLE. UPSTREAM SHOWERS IN THE CHARLESTON SC VICINITY MAY PASS NEAR THE COASTAL AIRPORTS AFTER 09Z. FOR DAYTIME WED...LOOKING AT MVFR POSSIBLE BRIEF IFR CONDITIONS FROM CONVECTION. THIS CONVECTION MAY DEVELOP ALONG A WEAK SFC TROF LIFTING NORTH ACROSS THE REGION...AND/OR ALONG THE LATE MORNING THRU EARLY EVENING INLAND PROGRESSING SEA BREEZE. FOR NOW...HAVE INDICATED VCTS AND WILL LET FOLLOWING SHIFTS UPDATE TO PINPOINT A MORE CONCRETE TIME FOR POSSIBLE MVFR/IFR CONVECTIVE CONDITIONS. BY THE MID TO LATE EVENING HRS...DIURNALLY DRIVEN CONVECTION SHOULD DISSIPATE. FORCING FOR CONVECTION FROM THE MESOSCALE INDUCED SEA BREEZE WILL DISSIPATE...AND THE SFC TROF SHOULD HAVE LIFTED NORTH OF THE FA. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM WEDNESDAY...HIGH PRESSURE NORTH OF BERMUDA WILL BE OUR CONTROLLING WEATHER SYSTEM THROUGH TONIGHT. TODAY`S SOUTH WINDS WILL VEER MORE SOUTHWESTERLY TONIGHT AS A COLD FRONT...CURRENTLY MOVING SE ACROSS ILLINOIS AND WISCONSIN...MOVES INTO WEST VIRGINIA AND KENTUCKY. AN UPPER LEVEL DISTURBANCE CURRENTLY MOVING NORTHEASTWARD ACROSS SOUTHERNMOST SOUTH CAROLINA MAY SPREAD ISOLATED SHOWERS ALONG THE NORTHEASTERN SOUTH CAROLINA COAST THIS MORNING...BUT LATEST HIGH- RES MODELS INDICATE COVERAGE OF STORMS WILL EXPAND ONCE THE DISTURBANCE REACHES SOUTHEASTERN NORTH CAROLINA LATE THIS MORNING AND EARLY THIS AFTERNOON. STEERING WINDS IN THE ATMOSPHERE WILL TEND TO PUSH STORMS NORTHEASTWARD AT 10 MPH...HOWEVER ASSUMING ENOUGH STORMS FORM COLLIDING OUTFLOW BOUNDARIES WILL ULTIMATELY DETERMINE WHERE STORMS MOVE. MARINERS IN THE CAPE FEAR AREA WILL WANT TO KEEP AN EYE ON THE SKY LATE THIS MORNING AND EARLY THIS AFTERNOON. SEAS CURRENTLY AROUND 2 FEET WILL BUILD CLOSER TO 3 FEET LATE THIS AFTERNOON AS WIND SPEEDS INCREASE WITH THE SEABREEZE. SW WINDS WILL INCREASE TO NEAR 15 KT TONIGHT. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... A PREFRONTAL TROUGH WILL BOOST WIND AND SEAS ON THURSDAY. WE ARE NOT ANTICIPATING HEADLINES OR ADVISORIES, BUT ITS BEEN FAIRLY QUIET SO THURSDAY WILL BE MORE UNSETTLED THAN THE PAST FEW DAYS WITH THE ADVENT OF SOME 4 FT SEAS. ON FRIDAY THIS BOUNDARY MOVES OFFSHORE AND WEAKENS IF NOT DISSIPATE ALTOGETHER. THE 20KT GUSTINESS SHOULD DROP OUT OF THE FORECAST AS WILL ANY 4 FT WAVES. A COLD FRONT WILL ALSO BE APPROACHING FROM THE NW ON FRIDAY BUT IT NOW LOOKS SLOWER THAN PREVIOUSLY FORECAST. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY... WITH THE SLOWER ARRIVAL OF COLD FRONT ON SATURDAY THE AREA MAY STAY IN AN INCREASED GRADIENT PRE-FRONTAL FLOW REGIME. AS SUCH WIND SPEEDS MAY NEED TO BE RE-EVALUATED AND RAISED ESPECIALLY AS SOME HIGHER MID LEVEL WINDS MAY BE IMPINGING UPON THE AREA. THE UPPER WAVE DRIVING THIS SYSTEM IS FAR FROM BEING SAMPLED BY THE UPPER AIR NETWORK HOWEVER AND SO NO LARGE CHANGES WILL BE MADE AT THIS TIME. SHOULD THINGS KEEP SLOWING DOWN THEN A SW WIND WILL REMAIN ON SUNDAY AS THE BOUNDARY EITHER STALLS ALONG THE COAST OR PERHAPS JUST INLAND. EITHER WAY THE STRONGER GRADIENT WILL HAVE PUSHED FURTHER OFFSHORE AND THE POSSIBILITY OF HIGHER WINDS AND SEAS THAN THE CURRENT FORECAST ALONG WITH IT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MBB NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...DCH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
315 AM EDT WED SEP 9 2015 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH FRIDAY AS WEAK LOW PRESSURE DEVELOPS TO THE WEST. LOW PRESSURE WILL PASS NORTH OF THE REGION SUNDAY PUSHING A COLD FRONT THROUGH THE AREA SUNDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 225 AM WED...UPR RDG TO THE S WILL CONT TO EXTEND N INTO THE REGION TODAY. WITH SFC HIGH OFFSHORE EXPECT S/SW LOW LVL FLOW WITH MOISTURE REMAINING QUITE HIGH...PWAT NEAR 2 INCHES. AS INSTAB DEVELOPS TODAY EXPECT SCT CONVECTION TO FORM ALONG SEA BRZ AND SHIFT INLAND WITH CHC POPS INLAND TO SLIGHT CHC CST. WITH DECENT AMOUNT OF SUN WILL SEE HIGHS NEAR 90 INLAND WITH MID/UPR 80S CST. && .SHORT TERM /TONIGHT/... AS OF 225 AM WED...SW FLOW ALOFT WILL INCREASE AS UPR TRF BEGINS TO APPROACH FROM THE W. MAY SEE JUST ENOUGH FORCING FROM THIS APPROACHING TRF TO KEEP ISOLD CONVECTION GOING OVERNIGHT...WITH BEST CVRG INLAND EARLY SHIFTING TOWARD CST LATE. WILL BE A VERY WARM NIGHT WITH SW LOW LVL FLOW...LOWS 70 TO 75 INLAND AND MID/UPR 70S BEACHES. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY...SUMMERLIKE PATTERN THROUGH THE FIRST PART OF THE LONG TERM PERIOD WITH SCATTERED SHOWERS AND THUNDERSTORMS, THEN A BETTER CHANCE OF PRECIP LATE IN THE WEEK, FOLLOWED BY A STRONG COLD FRONTAL PASSAGE AND COOLER/DRIER CONDITIONS BY EARLY NEXT WEEK. THURSDAY THROUGH FRIDAY...LARGE SCALE TROUGH ACROSS THE NORTHERN TIER OF THE CONUS WILL MIGRATE EASTWARD DURING THE PERIOD, WHILE UPPER RIDGE AMPLIFIES ACROSS THE INTERMOUNTAIN WEST. THIS WILL INDUCE STRONG DIGGING SHORTWAVE TROUGH ACROSS THE EASTERN US/OHIO VALLEY BY THE WEEKEND. AHEAD OF THIS SYSTEM IN RESPONSE, DEEP LAYER SOUTHWESTERLY FLOW WILL INDUCE VERY WARM AND HUMID CONDITIONS ACROSS EASTERN NC. WEAK SURFACE FRONT WILL SLOWLY MOVE THROUGH THE GREAT LAKES AREA, SOUTHEAST INTO THE WESTERN SLOPES OF THE APPALACHIAN MOUNTAINS ON THURSDAY. SLIGHTLY BETTER CHANCES FOR ORGANIZED PRECIP AS MOISTURE CONVERGENCE INCREASES OVER THE SOUTHEAST CONUS WITH NEARLY UNIDIRECTIONAL SW FLOW OVER EASTERN NC. MAINTAINED HIGH CHANCE POPS THURSDAY THROUGH FRIDAY FOR INLAND ZONES DUE TO HIGH PWATS AND SHORTWAVE ENERGY ROTATING AROUND STRONGER SHORTWAVE TO THE NORTHWEST. BULK OF UPPER LEVEL SUPPORT WILL REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL. CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO WITH HIGHS 85-90 AND LOWS IN THE 70S. THIS WEEKEND...MULTI-MODEL GUIDANCE HAS SHIFTED INTO BETTER AGREEMENT REGARDING TO EVOLUTION OF THE DIGGING STRONG SHORTWAVE THIS WEEKEND. 00Z GFS/GEM NOW VERY SIMILAR TO 00Z/PREVIOUS RUNS OF THE ECMWF, THEREFORE WILL CONTINUE MUCH OF THE PREVIOUS FORECAST THOUGH WITH GREATER CONFIDENCE IN EXPECTED SENSIBLE WX THIS WEEKEND. THE REGION WILL REMAIN IN THE WARM SECTOR WITH GOOD CHANCES OF SHOWERS AND STORMS ON SATURDAY. LATEST OPERATIONAL RUNS INDICATE A STRONG SHORTWAVE MAY ALSO CROSS THE REGION SATURDAY AFTERNOON, COINCIDENT WITH PEAK HEATING, THOUGH CLOUDS/PRECIP MAY INHIBIT MAXIMUM INSOLATION THEREBY LIMITING INSTABILITY SOMEWHAT. INCREASED POPS TO LIKELY FOR INLAND SECTIONS SATURDAY, TRANSLATING TO LIKELIES ALONG THE COAST SATURDAY NIGHT AS BEST CONVERGENCE AND MOISTURE SHIFTS OFFSHORE. INCREASING MID AND UPPER SW FLOW, ALONG WITH SHORTWAVE IN MEAN SW FLOW, COULD BRING A THREAT FOR SEVERE THUNDERSTORMS AS DEEP LAYER SHEAR INCREASES. THE LIMITING FACTOR FOR SEVERE THREAT WILL BE AMOUNT OF INSTABILITY. FOR SUNDAY, MORE QUESTIONABLE ON HOW QUICKLY SYSTEM EXITS THE EASTERN CONUS WITH A FASTER FRONTAL PASSAGE SOLUTION BRINGING DRIER AND COOLER CONDITIONS AND A SLOWER SCENARIO KEEPING SHOWER CHANCES THROUGH THE DAY. TRENDED POPS LOWER SUNDAY NIGHT INTO EARLY MONDAY FROM WEST TO EAST AS GUIDANCE HAS MOVED INTO BETTER AGREEMENT. MONDAY AND TUESDAY...HIGH PRESSURE WILL BUILD SOUTHEAST ACROSS THE REGION MONDAY AND TUESDAY. MONDAY SHOULD BRING A RETURN TO COOLER AND MUCH DRIER CONDITIONS WITH HIGHS IN THE 80-85 RANGE AND LOWS 60-65 INLAND TO 65-70 BEACHES. DEWPOINTS WILL BE DOWN INTO THE 50S BRINGING FIRST EARLY TOUCH OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /THROUGH TONIGHT/... AS OF 225 AM WED...MCLR SKIES...LIGHT WINDS AND HIGH LOW LVL MOISTURE ALL WOULD SEEM FAVORABLE FOR SOME FOG/ST TO DEVELOP THRU DAYBREAK. HIGH RES NARRE AND HRRR SHOW LITTLE TO NO IFR OVERNIGHT SO NOT REAL CONFIDENT HOW MUCH WILL FORM WITH LIGHT SSW LOW LVL FLOW. FOR NOW WILL SHOW PERIOD OF MAINLY IFR LATE. WHATEVER FOG OR ST DEVELOPS SHLD LIFT FAIRLY QUICKLY IN THE MORN WITH RETURN TO VFR. SCT SHRA/TSRA WILL DEVELOP TODAY WITH HEATING...VERY BRIEF REDUCTIONS IN CIGS/VSBYS POSS. ISOLD CONVECTION COULD CONT TONIGHT HOWEVER GIVEN UNCERTAIN CVRG WILL NOT MENTION IN TAFS. SLIGHTLY STRONGER SW LOW LVL FLOW AND DECENT AMOUNT OF CLOUDS SHLD LIMIT THREAT FOR LATE NIGHT FOG/ST. LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM WEDNESDAY...GENERALLY VFR THROUGH THE PERIOD, THOUGH OCCASIONAL FOG POSSIBLE EACH NIGHT/EARLY MORNING DUE TO LIGHT WINDS AND HIGH BOUNDARY LAYER MOISTURE. TEMPO RESTRICTIONS POSSIBLE EACH AFTERNOON DUE TO SCATTERED SHOWERS/THUNDERSTORMS. BETTER CHANCE FOR MORE WIDESPREAD SHOWERS/THUNDERSTORMS LATE WEEK INTO FIRST PART OF THE WEEKEND AHEAD OF A STRONG COLD FRONT. THE FRONT WILL CROSS EASTERN NC LATE SUNDAY INTO SUNDAY NIGHT. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 225 AM WED...HIGH PRES OFFSHORE AND DEVELOPING TRF TO THE W WILL LEAD TO MAINLY SW FLOW THRU THE PERIOD. GRDNT REMAINS FAIRLY LOOSE TODAY WITH SPEEDS MAINLY 8 TO 12 KTS. SPEEDS WILL INCREASE A BIT TONIGHT TO 10 TO 15 KTS. SEAS OF 2 TO 3 FEET TODAY WILL BUILD A BIT WITH 3 TO 4 FEET OUTER WATERS LATER TONIGHT. LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 315 AM WEDNESDAY...A TIGHTENING SOUTHWESTERLY PRESSURE GRADIENT WILL CREATE POOR BOATING CONDITIONS THURSDAY THROUGH THE WEEKEND. WINDS WILL BE SW 5-15 KT THROUGH EARLY THURSDAY, THEN INCREASE TO 10-20 KT LATER THURSDAY, HIGHEST ON THE OUTER PORTIONS OF THE COASTAL WATERS. SEAS WILL GENERALLY BE 3 FEET OR LESS THROUGH EARLY THURSDAY, THEN BUILD 3-5 FT THURSDAY INTO FRIDAY IN RESPONSE TO STRENGTHENING SOUTHWESTERLY WINDS. STRONG COLD FRONT WILL APPROACH BY LATE WEEKEND AND CROSS THE EASTERN NC WATERS LATE SUNDAY NIGHT INTO MONDAY. FORECAST CONFIDENCE HAS INCREASED WITH REGARDS TO WEEKEND SCENARIO DUE TO MUCH BETTER AGREEMENT AMONGST MEDIUM/LONG RANGE GUIDANCE. CONDITIONS COULD REACH MARGINAL SCA CRITERIA WITH WIND GUSTS TO 25 KT AND 6 FT SEAS LATE SATURDAY INTO EARLY SUNDAY AHEAD OF THE STRONG COLD FRONT. WAVEWATCH AND LOCAL SWAN/NWPS IN GOOD AGREEMENT THROUGH THE MEDIUM RANGE, THEN WAVEWATCH APPEARED REASONABLE FOR THE EXTENDED SEAS AS ITS GFS- BASED WINDS ARE BETTER IN LINE WITH FORECAST WINDS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...RF NEAR TERM...RF SHORT TERM...RF LONG TERM...DAG/TL AVIATION...RF/DAG MARINE...RF/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
236 AM EDT WED SEP 9 2015 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH FRIDAY AS WEAK LOW PRESSURE DEVELOPS TO THE WEST. LOW PRESSURE WILL PASS NORTH OF THE REGION SUNDAY PUSHING A COLD FRONT THROUGH THE AREA SUNDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 225 AM WED...UPR RDG TO THE S WILL CONT TO EXTEND N INTO THE REGION TODAY. WITH SFC HIGH OFFSHORE EXPECT S/SW LOW LVL FLOW WITH MOISTURE REMAINING QUITE HIGH...PWAT NEAR 2 INCHES. AS INSTAB DEVELOPS TODAY EXPECT SCT CONVECTION TO FORM ALONG SEA BRZ AND SHIFT INLAND WITH CHC POPS INLAND TO SLIGHT CHC CST. WITH DECENT AMOUNT OF SUN WILL SEE HIGHS NEAR 90 INLAND WITH MID/UPR 80S CST. && .SHORT TERM /TONIGHT/... AS OF 225 AM WED...SW FLOW ALOFT WILL INCREASE AS UPR TRF BEGINS TO APPROACH FROM THE W. MAY SEE JUST ENOUGH FORCING FROM THIS APPROACHING TRF TO KEEP ISOLD CONVECTION GOING OVERNIGHT...WITH BEST CVRG INLAND EARLY SHIFTING TOWARD CST LATE. WILL BE A VERY WARM NIGHT WITH SW LOW LVL FLOW...LOWS 70 TO 75 INLAND AND MID/UPR 70S BEACHES. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 315 PM TUESDAY...SUMMERLIKE PATTERN THROUGH THE FIRST PART OF THE LONG TERM PERIOD WITH SCATTERED SHOWERS AND THUNDERSTORMS, THEN A BETTER CHANCE OF PRECIP LATE IN THE WEEK, FOLLOWED BY A POSSIBLE STRONG COLD FRONTAL PASSAGE AND COOLER/DRIER CONDITIONS BY LATE WEEKEND/EARLY NEXT WEEK. THURSDAY THROUGH FRIDAY...LARGE SCALE TROUGH ACROSS THE NORTHERN TIER OF THE CONUS WILL MIGRATE EASTWARD DURING THE PERIOD, WHILE UPR RIDGE AMPLIFIES ACROSS THE INTERMOUNTAIN WEST. THIS WILL INDUCE STRONG DIGGING SHORTWAVE TROUGH ACROSS THE EASTERN US/OHIO VALLEY BY THE WEEKEND. AHEAD OF THIS SYSTEM IN RESPONSE...DEEP LAYER SWRLY FLOW WILL PUMP IN VERY WARM AND HUMID CONDITIONS. WEAK SURFACE FRONT WILL SLOWLY MOVE THROUGH THE GREAT LAKES AREA, SOUTHEAST INTO THE WESTERN SLOPES OF THE APPALACHIAN MOUNTAINS ON THURSDAY. SLIGHTLY BETTER CHANCES FOR ORGANIZED PRECIP AS MOISTURE CONVERGENCE INCREASES OVER THE SOUTHEAST CONUS WITH NEARLY UNIDIRECTIONAL SW FLOW OVER EASTERN NC. MAINTAINED HIGH CHANCE POPS THURSDAY THROUGH FRIDAY FOR INLAND ZONES DUE TO HIGH PWATS AND PIECES OF SHORTWAVE ENERGY ROTATING AROUND STRONGER SHORTWAVE TO THE NORTH AND WEST. THE BULK OF UPPER LEVEL SUPPORT WILL REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL. CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO WITH HIGHS 85-90 AND LOWS IN THE 70S. THIS WEEKEND...THERE ARE STILL SOME DIFFERENCES AMONGST MODEL SUITE IN REGARDS TO EVOLUTION OF THE DIGGING STRONG SHORTWAVE THIS WEEKEND. HAVE CONTINUED TO FOLLOW MORE CLOSELY TO WPC/ECMWF SOLN. A LOOK AT THE ENSEMBLE MEAN HEIGHTS INDICATE THE NCEP/ECM ENSEMBLE MEAN ALONG WITH ECMWF/GEM GLOBAL HAVE FAIRLY UNANIMOUS SUPPORT WITH HANDLING UP UPR LOW/SHORTWAVE POSITIONING ACROSS THE OHIO VALLEY...WHILE DETERMINISTIC GFS STILL A BIT OF AN OUTLIER. THIS WILL KEEP AREA IN THE WARM SECTOR WITH GOOD CHANCES OF SHOWERS AND STORMS ON SATURDAY. WILL RAISE POPS A BIT...INTO THE 40-50 PERCENT RANGE. INCREASING MID AND UPPER SW FLOW COULD BRING A THREAT FOR SEVERE STORMS AS DEEP LAYER SHEAR INCREASES...WITH SEVERE THREAT BEING DEPENDENT ON AMOUNT OF AVAILABLE INSTABILITY. FOR SUNDAY, MORE QUESTIONABLE ON HOW QUICKLY SYSTEM EXITS THE EASTERN CONUS WITH A FASTER FRONTAL PASSAGE SOLUTION BRINGING DRIER AND COOLER CONDITIONS AND A SLOWER SCENARIO KEEPING SHOWER CHANCES THROUGH THE DAY. FOR NOW WILL MAINTAIN THE 30 POPS. MONDAY AND TUESDAY...MONDAY SHOULD BRING A RETURN TO COOLER AND MUCH DRIER CONDITIONS WITH HIGHS IN THE 80-85 RANGE AND LOWS 60-65 INLAND TO 65-70 BEACHES. TD`S WILL BE DOWN INTO THE 50S BRINGING FIRST EARLY TOUCH OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /THROUGH TONIGHT/... AS OF 225 AM WED...MCLR SKIES...LIGHT WINDS AND HIGH LOW LVL MOISTURE ALL WOULD SEEM FAVORABLE FOR SOME FOG/ST TO DEVELOP THRU DAYBREAK. HIGH RES NARRE AND HRRR SHOW LITTLE TO NO IFR OVERNIGHT SO NOT REAL CONFIDENT HOW MUCH WILL FORM WITH LIGHT SSW LOW LVL FLOW. FOR NOW WILL SHOW PERIOD OF MAINLY IFR LATE. WHATEVER FOG OR ST DEVELOPS SHLD LIFT FAIRLY QUICKLY IN THE MORN WITH RETURN TO VFR. SCT SHRA/TSRA WILL DEVELOP TODAY WITH HEATING...VERY BRIEF REDUCTIONS IN CIGS/VSBYS POSS. ISOLD CONVECTION COULD CONT TONIGHT HOWEVER GIVEN UNCERTAIN CVRG WILL NOT MENTION IN TAFS. SLIGHTLY STRONGER SW LOW LVL FLOW AND DECENT AMOUNT OF CLOUDS SHLD LIMIT THREAT FOR LATE NIGHT FOG/ST. LONG TERM /THU THROUGH SUNDAY/... AS OF 315 PM TUESDAY...GENERALLY VFR THROUGH THE PERIOD, THOUGH OCCASIONAL FOG POSSIBLE EACH NIGHT/EARLY MORNING DUE TO CALM WINDS AND HIGH BOUNDARY LAYER MOISTURE. TEMPO RESTRICTIONS POSSIBLE EACH AFTERNOON DUE TO SCATTERED SHOWERS/THUNDERSTORMS. BETTER CHANCE FOR MORE WIDESPREAD SHOWERS/THUNDERSTORMS LATE WEEK INTO FIRST PART OF THE WEEKEND AHEAD OF A STRONG COLD FRONT. WINDS WILL INC OUT OF THE SW ON THUR AND BECOME GUSTY 12-16 KT. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 225 AM WED...HIGH PRES OFFSHORE AND DEVELOPING TRF TO THE W WILL LEAD TO MAINLY SW FLOW THRU THE PERIOD. GRDNT REMAINS FAIRLY LOOSE TODAY WITH SPEEDS MAINLY 8 TO 12 KTS. SPEEDS WILL INCREASE A BIT TONIGHT TO 10 TO 15 KTS. SEAS OF 2 TO 3 FEET TODAY WILL BUILD A BIT WITH 3 TO 4 FEET OUTER WTRS LATER TONIGHT. LONG TERM /THU THROUGH SUNDAY/... AS OF 315 PM TUESDAY...A TIGHTENING SOUTHWESTERLY PRESSURE GRADIENT WILL CREATE MARGINAL CONDITIONS BY THURSDAY THROUGH THE WEEKEND. WINDS WILL BE SW 5-15 KT THROUGH EARLY THURSDAY, THEN INCREASE TO 10-20 KT LATER THURSDAY, HIGHEST ON THE OUTER PORTIONS OF THE COASTAL WATERS. SEAS WILL GENERALLY BE 3 FEET OR LESS THROUGH EARLY THURSDAY, THEN BUILD 3-5 FT THURSDAY INTO FRIDAY IN RESPONSE TO STRENGTHENING SOUTHWESTERLY WINDS. STRONG COLD FRONT WILL APPROACH BY LATE WEEKEND, THOUGH FORECAST CONFIDENCE STILL RELATIVELY LOW AT THIS TIME DUE TO DISAGREEMENT AMONGST GUIDANCE IN THE FAR EXTENDED PERIOD. CONTINUED AROUND A FOOT HIGHER THAN 12Z WAVEWATCH GUIDANCE AS ITS GFS-BASED WINDS WERE LOWER THAN FCST 15-20 KT SUSTAINED WINDS. CONDITIONS COULD REACH MARGINAL SCA CRITERIA WITH 6 FOOT SEAS FOR A TIME LATE SATURDAY INTO EARLY SUNDAY AHEAD OF THE STRONG COLD FRONT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...RF NEAR TERM...RF SHORT TERM...RF LONG TERM...TL/DAG AVIATION...RF/TL MARINE...RF/TL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
150 AM EDT WED SEP 9 2015 .SYNOPSIS... SUMMERTIME HEAT AND HUMIDITY WILL RETURN AS HIGH PRESSURE CONTINUES OVER THE REGION THROUGH THURSDAY. A COLD FRONT WILL APPROACH FROM THE WEST THURSDAY AFTERNOON AND THEN STALL ALONG THE COAST WHICH WILL INCREASE THE RISK FOR THUNDERSTORMS INTO THE WEEKEND. THE FRONT WILL SLOWLY DISSIPATE EARLY NEXT WEEK AS HIGH PRESSURE RETURNS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 100 AM WEDNESDAY...SHOWERS ARE DEVELOPING UPSTREAM IN THE CHARLESTON VICINITY MUCH LIKE THE 02Z HRRR INDICATES. ADVECTION OF THIS CONVECTION ACROSS THE SANTEE RIVER INTO NE SOUTH CAROLINA IS POSSIBLE AFTER 2-3 AM. OTHERWISE SKIES ARE CURRENTLY CLEAR TO PARTLY CLOUDY WITH PATCHY FOG ACROSS THE AREA. UPDATES WITH THIS FINAL NEAR-TERM UPDATE OF THE NIGHT INCLUDE TWEAKS TO SKY...WIND...AND DEWPOINT. DISCUSSION FROM 1000 PM FOLLOWS... THE HIGH RESOLUTION MODELS CONTINUE TO SHOW SOME UPTICK IN CONVECTION AS DAYBREAK APPROACHES. WEAK LOW PRESSURE ACROSS GEORGIA DOES LIFT N ACROSS SOUTH CAROLINA OVERNIGHT. GIVEN HOW QUICKLY CONVECTION HAS DISSIPATED THIS EVE...WILL CONFINE MENTIONABLE POPS TO THE CLIMATOLOGICALLY FAVORED WARM OCEAN WATERS AND ADJACENT IMMEDIATE COAST WITH THE APPROACH OF DAYBREAK WHERE SOME WEAK LOW-LEVEL CONVERGENCE WAS NOTED. PROFILES DO NOT SUPPORT DENSE FOG OVERNIGHT. THE WEDGE WHICH HAD BEEN IN PLACE LAST NIGHT...HAS BROKEN DOWN AND WARM SOUTHERLY WINDS HAVE RETURNED. WINDS ABOVE THE BOUNDARY LAYER WILL BE IN THE 15 TO 20 KT RANGE FOR MOST OF THE OVERNIGHT. CONSIDERABLE CONVECTIVE CLOUD DEBRIS SHOULD CONTINUE TO FILTER ACROSS THE AREA FROM THE SOUTH. GIVEN THE LACK OF SIGNALS SUPPORTING SIGNIFICANT FOG...WILL OPT TO LEAVE FOG OUT OF THE FORECAST. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... AS OF 300 PM TUESDAY...UPPER LEVEL HIGH PRESSURE CENTERED OVER THE FLORIDA STRAITS WILL BRING IN VERY WARM 500 MB TEMPERATURES OF - 5.5C. THIS COMBINED WITH PRECIPITABLE WATER OF AROUND 2 INCHES WILL PROVIDE ABOVE NORMAL TEMPERATURES AND SCATTERED DIURNAL CONVECTION FOR WEDNESDAY. HIGHS ARE EXPECTED TO REACH INTO THE LOWER 90S INLAND AND NEAR NINETY AT THE BEACHES. ALOFT THE SOUTHERLY FLOW WILL SLOWLY VEER TO THE SOUTHWEST AHEAD OF COLD FRONT THAT WILL APPROACH THE REGION ON THURSDAY BEFORE STALLING INTO THE AREA OVERNIGHT. LITTLE TO NO STRONG SYNOPTIC FORCING BOTH WEDNESDAY AND THURSDAY SO MESOSCALE LIFT WILL BE THE MAIN TRIGGER FOR THE SCATTERED LOCATION EACH DAY. WITH THE FRONTAL BOUNDARY STILL LINGERING TO THE WEST ON THURSDAY HIGHS ARE EXPECTED TO THE LOWER 90S MOST LOCALES. LOW TEMPERATURE BOTH DAYS ARE EXPECTED TO FALL INTO THE LOWER TO MIDDLE 70S. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... AS OF 300 PM TUESDAY...THE EXTENDED FORECAST WILL BE DOMINATED BY SIGNIFICANT AMPLITUDE AT THE MID LEVELS AT LEAST THROUGH THE WEEKEND. A POTENT TROUGH WILL DEEPEN FURTHER AND POSSIBLY EVEN CUTOFF AS ADVERTISED BY SOME GUIDANCE BUT CERTAINLY DEEPEN THROUGH SUNDAY BEFORE FINALLY GETTING KICKED BY AN UPSTREAM SYSTEM OPENING UP AND MOVING OFF IN THE WESTERLIES. AT THE SURFACE A FRONT WILL BE ESSENTIALLY STATIONARY OVER THE CWA THROUGH MONDAY MORNING FINALLY PUSHING THROUGH AS THE TROUGH LIFTS OUT. WITH THE TROUGH IN THE MIDWEST...THE EASTERN CAROLINAS WILL BE UNDER A DEEP AND MOIST SOUTHWEST FLOW THUS SHOWERS AND THUNDERSTORMS ARE FAIR GAME JUST ABOUT ANYTIME. IT APPEARS THE BEST SHOT AT LEAST WITH THE LATEST GUIDANCE APPEARS TO BE SATURDAY INTO EARLY SUNDAY WHEN THE MOISTURE AND LOW LEVEL FORCING TEAM UP WITH A DECENT 300MB JET. TEMPERATURE FORECAST REMAINS BASICALLY UNCHANGED WITH LOW DIURNAL RANGES EARLY WITH A COOL DOWN AND HIGHER SPREAD MONDAY AND TUESDAY. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...LOW STRATUS AND FOG IS MOST LIKELY TO OCCUR AT THE INLAND AIRPORTS: FLO AND LBT. THE LATEST HRRR MODEL (WHICH HAS DONE VERY WELL THE PAST SEVERAL NIGHTS) SHOWS LOW CEILINGS INTERMITTENTLY PRESENT AT THESE SITES BETWEEN 08-12Z. CLOSER TO THE COAST THE AIRMASS SHOULD SUPPORT THE DEVELOPMENT OF LOW MARITIME CUMULUS IN A MOIST ONSHORE FLOW BEGINNING 08-09Z...WITH TEMPORARY MVFR CEILINGS POSSIBLE. UPSTREAM SHOWERS IN THE CHARLESTON SC VICINITY MAY PASS NEAR THE COASTAL AIRPORTS AFTER 09Z. FOR DAYTIME WED...LOOKING AT MVFR POSSIBLE BRIEF IFR CONDITIONS FROM CONVECTION. THIS CONVECTION MAY DEVELOP ALONG A WEAK SFC TROF LIFTING NORTH ACROSS THE REGION...AND/OR ALONG THE LATE MORNING THRU EARLY EVENING INLAND PROGRESSING SEA BREEZE. FOR NOW...HAVE INDICATED VCTS AND WILL LET FOLLOWING SHIFTS UPDATE TO PINPOINT A MORE CONCRETE TIME FOR POSSIBLE MVFR/IFR CONVECTIVE CONDITIONS. BY THE MID TO LATE EVENING HRS...DIURNALLY DRIVEN CONVECTION SHOULD DISSIPATE. FORCING FOR CONVECTION FROM THE MESOSCALE INDUCED SEA BREEZE WILL DISSIPATE...AND THE SFC TROF SHOULD HAVE LIFTED NORTH OF THE FA. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 100 AM WEDNESDAY...CURRENTLY OBSERVATIONS INDICATE WINDS LESS THAN 10 KNOTS EXCEPT RIGHT UP ON THE BEACHES WHERE SOME RECENT GUSTS HAVE BEEN IN THE 12-14 KNOT RANGE. MINOR TWEAKS ARE ALL THAT ARE NEEDED TO THE FORECAST. DISCUSSION FROM 1000 PM FOLLOWS... SOUTHERLY WINDS WILL REMAIN IN PLACE OVERNIGHT AHEAD OF AN INLAND TROUGH. THIS SHOULD KEEP WINDS IN THE 10 TO 15 KT RANGE. SEAS OF MAINLY 2 FT SHOULD BUILD A HALF FOOT TO A FOOT THROUGH WED MORNING. CONVECTION IS EXPECTED TO DEVELOP ACROSS THE WATERS AND OFFSHORE DURING THE LATE NIGHT AND MORNING HOURS OF WED. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 PM TUESDAY...HIGH PRESSURE DURING THE EARLY PORTION OF THIS PERIOD WILL SLOWLY WEAKEN AS A FRONTAL BOUNDARY MOVES INTO THE CENTRAL PORTIONS OF THE CAROLINAS BY THURSDAY NIGHT. WINDS WILL BECOME MORE SOUTHWESTERLY WITH TIME AND A INCREASE IN WINDS OF 15 TO 20 KNOTS IS EXPECTED THURSDAY NIGHT. SEAS ARE EXPECTED TO SLOWLY BUILD INTO THE 3 TO 4 FT RANGE BY FRIDAY NIGHT WITH AN ISOLATED 5 FOOTER POSSIBLE. A SMALL CRAFT EXERCISE CAUTION IS POSSIBLE THURSDAY NIGHT. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 300 PM TUESDAY...WINDS WILL BE MOSTLY FROM THE SOUTHWEST FRIDAY AND SATURDAY AS A COLD FRONT GETS HUNG UP INLAND. WIND SPEEDS SEEM TO BE HIGHEST FRIDAY BEFORE THE FRONT WEAKENS AND IN THE 10-15 KNOT RANGE. SATURDAY WINDS SHOULD DIMINISH TO NEAR TEN KNOTS. TOUGH CALL ON WINDS FOR SUNDAY AS LOW PRESSURE IS PROGGED TO DEVELOP INLAND WHICH WILL TURN THE WINDS TO THE SOUTHEAST FOR A WHILE. SIGNIFICANT SEAS SHOULD END UP IN A 1-3 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...RJD NEAR TERM...RJD/TRA SHORT TERM...DRH LONG TERM...SHK AVIATION...DCH/TRA
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1230 AM EDT WED SEP 9 2015 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE THROUGH MIDWEEK AS WEAK LOW PRESSURE DEVELOPS TO THE WEST. A STRONG COLD FRONT WILL APPROACH FROM THE WEST LATE IN THE WEEK AND CROSS THE AREA BY LATE THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1225 AM WED...NO SIGNIF CHANGES OVERNIGHT WITH MOST AREAS REMAINING DRY. DID ADD SLIGHT POP TOWARD DAYBREAK NEAR S CST WHERE MDLS SHOW SOME POSS OF SHRA/TSRA DEVELOPING. PREV DISC...PRECIPITATION HAS DISSIPATED ACROSS OUR CWA AND HAVE REMOVED ALL POPS FROM THE FORECAST OVERNIGHT. LATEST RUN OF THE 3KM HRRR AND RUC MODELS INDICATE NO ADDITIONAL PRECIPITATION OVER LAND AREAS OVERNIGHT. WITH HIGH LOW- LEVEL MOISTURE AND LIGHT WINDS...FOG IS A GOOD BET OVERNIGHT. NO CHANGES TO FORECAST TEMPERATURES WITH LOWS AROUND 70 INLAND TO MID 70S BEACHES. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TODAY/... AS OF 2 PM TUE...WEAK UPPER RIDGING OVER THE BAHAMAS/FLORIDA WITH LONG WAVE TROUGHING ACROSS THE UPPER PLAINS/MIDWEST WILL RESULT IN SOUTHWESTERLY FLOW ALOFT. S TO SW SFC SFC WINDS WILL RESULT IN WARM AND MUGGY CONDITIONS ALONG WITH ISOLATED TO SCATTERED DIURNAL SHOWERS AND THUNDERSTORMS...BEST CHANCES ALONG THE SEA BREEZE. COASTAL AREAS SHOULD REMAIN MOSTLY DRY AND THE SEVERE THREAT IS LOW DUE TO WEAK UPPER LEVEL SUPPORT. HIGHS WILL RANGE FROM NEAR 90 INLAND TO MID 80S BEACHES. && .LONG TERM /TONIGHT THROUGH TUESDAY/... AS OF 315 PM TUESDAY...SUMMERLIKE PATTERN THROUGH THE FIRST PART OF THE LONG TERM PERIOD WITH SCATTERED SHOWERS AND THUNDERSTORMS, THEN A BETTER CHANCE OF PRECIP LATE IN THE WEEK, FOLLOWED BY A POSSIBLE STRONG COLD FRONTAL PASSAGE AND COOLER/DRIER CONDITIONS BY LATE WEEKEND/EARLY NEXT WEEK. THURSDAY THROUGH FRIDAY...LARGE SCALE TROUGH ACROSS THE NORTHERN TIER OF THE CONUS WILL MIGRATE EASTWARD DURING THE PERIOD, WHILE UPR RIDGE AMPLIFIES ACROSS THE INTERMOUNTAIN WEST. THIS WILL INDUCE STRONG DIGGING SHORTWAVE TROUGH ACROSS THE EASTERN US/OHIO VALLEY BY THE WEEKEND. AHEAD OF THIS SYSTEM IN RESPONSE...DEEP LAYER SWRLY FLOW WILL PUMP IN VERY WARM AND HUMID CONDITIONS. WEAK SURFACE FRONT WILL SLOWLY MOVE THROUGH THE GREAT LAKES AREA, SOUTHEAST INTO THE WESTERN SLOPES OF THE APPALACHIAN MOUNTAINS ON THURSDAY. SLIGHTLY BETTER CHANCES FOR ORGANIZED PRECIP AS MOISTURE CONVERGENCE INCREASES OVER THE SOUTHEAST CONUS WITH NEARLY UNIDIRECTIONAL SW FLOW OVER EASTERN NC. MAINTAINED HIGH CHANCE POPS THURSDAY THROUGH FRIDAY FOR INLAND ZONES DUE TO HIGH PWATS AND PIECES OF SHORTWAVE ENERGY ROTATING AROUND STRONGER SHORTWAVE TO THE NORTH AND WEST. THE BULK OF UPPER LEVEL SUPPORT WILL REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL. CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO WITH HIGHS 85-90 AND LOWS IN THE 70S. THIS WEEKEND...THERE ARE STILL SOME DIFFERENCES AMONGST MODEL SUITE IN REGARDS TO EVOLUTION OF THE DIGGING STRONG SHORTWAVE THIS WEEKEND. HAVE CONTINUED TO FOLLOW MORE CLOSELY TO WPC/ECMWF SOLN. A LOOK AT THE ENSEMBLE MEAN HEIGHTS INDICATE THE NCEP/ECM ENSEMBLE MEAN ALONG WITH ECMWF/GEM GLOBAL HAVE FAIRLY UNANIMOUS SUPPORT WITH HANDLING UP UPR LOW/SHORTWAVE POSITIONING ACROSS THE OHIO VALLEY...WHILE DETERMINISTIC GFS STILL A BIT OF AN OUTLIER. THIS WILL KEEP AREA IN THE WARM SECTOR WITH GOOD CHANCES OF SHOWERS AND STORMS ON SATURDAY. WILL RAISE POPS A BIT...INTO THE 40-50 PERCENT RANGE. INCREASING MID AND UPPER SW FLOW COULD BRING A THREAT FOR SEVERE STORMS AS DEEP LAYER SHEAR INCREASES...WITH SEVERE THREAT BEING DEPENDENT ON AMOUNT OF AVAILABLE INSTABILITY. FOR SUNDAY, MORE QUESTIONABLE ON HOW QUICKLY SYSTEM EXITS THE EASTERN CONUS WITH A FASTER FRONTAL PASSAGE SOLUTION BRINGING DRIER AND COOLER CONDITIONS AND A SLOWER SCENARIO KEEPING SHOWER CHANCES THROUGH THE DAY. FOR NOW WILL MAINTAIN THE 30 POPS. MONDAY AND TUESDAY...MONDAY SHOULD BRING A RETURN TO COOLER AND MUCH DRIER CONDITIONS WITH HIGHS IN THE 80-85 RANGE AND LOWS 60-65 INLAND TO 65-70 BEACHES. TD`S WILL BE DOWN INTO THE 50S BRINGING FIRST EARLY TOUCH OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /THROUGH 00Z THURSDAY/... AS OF 1225 AM WED...MCLR SKIES...LIGHT WINDS AND HIGH LOW LVL MOISTURE ALL WOULD SEEM FAVORABLE FOR SOME FOG/ST TO DEVELOP. HIGH RES NARRE AND HRRR SHOW LITTLE TO NO IFR OVERNIGHT SO NOT REAL CONFIDENT HOW MUCH WILL FORM WITH LIGHT SSW LOW LVL FLOW. FOR NOW WILL SHOW PERIOD OF IFR INLAND AND MVFR CST LATER TONIGHT. WHATEVER FOG OR ST DEVELOPS SHLD LIFT FAIRLY QUICKLY IN THE MORN WITH RETURN TO VFR. SCT SHRA/TSRA WILL DEVELOP WED WITH HEATING WITH VERY BRIEF REDUCTIONS IN CIGS/VSBYS POSS. LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/ AS OF 315 PM TUESDAY...GENERALLY VFR THROUGH THE PERIOD, THOUGH OCCASIONAL FOG POSSIBLE EACH NIGHT/EARLY MORNING DUE TO CALM WINDS AND HIGH BOUNDARY LAYER MOISTURE. TEMPO RESTRICTIONS POSSIBLE EACH AFTERNOON DUE TO SCATTERED SHOWERS/THUNDERSTORMS. BETTER CHANCE FOR MORE WIDESPREAD SHOWERS/THUNDERSTORMS LATE WEEK INTO FIRST PART OF THE WEEKEND AHEAD OF A STRONG COLD FRONT. WINDS WILL INC OUT OF THE SW ON THUR AND BECOME GUSTY 12-16 KT. && .MARINE... SHORT TERM /TONIGHT THROUGH WEDNESDAY/... AS OF 1225 AM WED...FCST LOOKS GOOD WITH NO SIGNIF CHANGES PLANNED. PREV DISC...MINOR ADJUSTMENTS TO WIND DIRECTION AS WINDS ARE GENERALLY SE/S AT SPEEDS OF 10 KNOTS OR LESS WITH SEAS GENERALLY 2 TO 3 FEET WITH SOME LONGER PERIOD SWELL ENERGY. NO CHANGES TO THIS ARE EXPECTED OVERNIGHT. WINDS VEER TO MORE SW BY EARLY WEDNESDAY AS AXIS OF HIGH PRESSURE RIDGE SHIFTS OFFSHORE. SEAS CONTINUE AT 2 TO 3 FEET FOR WEDNESDAY. LONG TERM /WED NIGHT THROUGH SUNDAY/ AS OF 315 PM TUESDAY...GENERALLY GOOD BOATING CONDITIONS CONTINUE THROUGH WEDNESDAY NIGHT, THEN A TIGHTENING SOUTHWESTERLY PRESSURE GRADIENT WILL CREATE MARGINAL CONDITIONS BY THURSDAY THROUGH THE WEEKEND. WINDS WILL BE SW 5-15 KT WEDNESDAY NIGHT THROUGH EARLY THURSDAY, THEN INCREASE TO 10-20 KT LATER THURSDAY, HIGHEST ON THE OUTER PORTIONS OF THE COASTAL WATERS. SEAS WILL GENERALLY BE 3 FEET OR LESS THROUGH EARLY THURSDAY, THEN BUILD 3-5 FT THURSDAY INTO FRIDAY IN RESPONSE TO STRENGTHENING SOUTHWESTERLY WINDS. STRONG COLD FRONT WILL APPROACH BY LATE WEEKEND, THOUGH FORECAST CONFIDENCE STILL RELATIVELY LOW AT THIS TIME DUE TO DISAGREEMENT AMONGST GUIDANCE IN THE FAR EXTENDED PERIOD. CONTINUED AROUND A FOOT HIGHER THAN 12Z WAVEWATCH GUIDANCE AS ITS GFS-BASED WINDS WERE LOWER THAN FCST 15-20 KT SUSTAINED WINDS. CONDITIONS COULD REACH MARGINAL SCA CRITERIA WITH 6 FOOT SEAS FOR A TIME LATE SATURDAY INTO EARLY SUNDAY AHEAD OF THE STRONG COLD FRONT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JAC NEAR TERM...RF/CTC SHORT TERM...JAC LONG TERM...DAG/TL AVIATION...RF/TL MARINE...RF/CTC/TL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1250 AM CDT WED SEP 9 2015 .UPDATE... ISSUED AT 1250 AM CDT WED SEP 9 2015 COLD FRONTAL BOUNDARY WILL CONTINUE TO MOVE SLOWLY SOUTH INTO THE NORTHERN PLAINS LATE TONIGHT THROUGH WEDNESDAY. COMBINED WITH MID LEVEL EMBEDDED S/WV TROUGHS AND UPPER LEVEL JET DYNAMICS...CLOUD COVER AND CHANCES FOR LIGHT SHOWERS CAN BE EXPECTED EARLY THIS MORNING THROUGH AT LEAST WEDNESDAY NIGHT STARTING NORTH AND SLOWLY EXPANDING SOUTHWARD ALONG THE FROPA. HAVE A SLIGHT CHANCE OF SHOWERS NOW STARTING IN THE NORTHWEST AND EXPANDING EAST AND SLIGHTLY SOUTH WITH TIME THROUGH THE AM HOURS. JET ENTRANCE DYNAMICS TRIGGERING AN AREA OF LIGHT SHOWERS NOW MOVING INTO NORTHEASTERN MONTANA. WITH CLOUD BASES AROUND 10K FT AGL IN SOUTHERN SASKATCHEWAN...UNSURE HOW MUCH OF THE RADAR RETURNS ARE ACTUALLY REACHING THE GROUND. WILL INCREASE POPS ACCORDINGLY IF WE START MEASURING. UPDATE ISSUED AT 848 PM CDT TUE SEP 8 2015 AT 830 PM CDT...A COLD FRONTAL BOUNDARY EXTENDED ACROSS SOUTHWEST SASKATCHEWAN. THE FRONT WILL SLOWLY SLIDE SOUTHEAST TONIGHT AND WEDNESDAY WITH ONLY A SLOW SOUTHWARD MOVING COMPONENT AS IT NEARLY ALIGNS WITH THE FLOW ALOFT. LATEST HRRR MODEL RUNS SHOW SOME SCATTERED SHOWERS ACROSS THE NORTHWEST AFTER 09Z TONIGHT AND NORTH CENTRAL AFTER 12Z WEDNESDAY. ADDED MORE SLIGHT CHANCE AREA TO THE NORTHWEST IN CONCERT WITH THE HRRR AFTER 09Z. OTHERWISE CURRENT FORECAST LOOKS GOOD. UPDATE ISSUED AT 553 PM CDT TUE SEP 8 2015 THE NORTHERN PLAINS REMAINS ON THE SOUTHERN EDGE OF A LARGE UPPER LOW ACROSS NORTHERN MANITOBA. THIS HAS MAINTAINED A BREEZY NORTHWEST FLOW ACROSS THE REGION SO FAR THIS AFTERNOON. AS THE EVENING APPROACHES EXPECT WINDS TO DIMINISH AFTER 7 PM AND SKIES TO BECOME MOSTLY CLEAR. UPDATED CURRENT OBSERVATIONS AND SKY CONDITION ONLY. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 239 PM CDT TUE SEP 8 2015 QUIET WEATHER HIGHLIGHTS THE SHORT TERM FORECAST. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE 12 UTC GUIDANCE SUITES. OVERALL...WEAK HIGH PRESSURE ACROSS WESTERN AND CENTRAL NORTH DAKOTA SOUTH OF THE FILLING NORTHERN MANITOBA LOW WILL CONTINUE TO WEAKEN THROUGH THE NIGHT. A WEAK IMPULSE EMBEDDED IN NORTHWEST FLOW ALOFT ON WEDNESDAY MAY SUPPORT ISOLATED RAIN SHOWER DEVELOPMENT DURING THE AFTERNOON. GIVEN WEAK MID LEVEL LAPSE RATES...DID NOT INCLUDE A MENTION OF THUNDER AT THIS TIME. TEMPERATURES WEDNESDAY ARE EXPECTED TO BE SIMILAR TO TODAY WITH 60S NORTH AND 70S SOUTH. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 239 PM CDT TUE SEP 8 2015 NO MAIN CONCERNS IN THE LONG TERM WITH FAIRLY DRY AND QUIET WEATHER EXPECTED. EARLY IN THE LONG TERM THE NORTHWEST FLOW ALOFT WITH A FEW UPPER LEVEL SHORTWAVES...COMBINED WITH A COLD FRONTAL BOUNDARY OVER THE STATE WILL KEEP SMALL CHANCES OF SHOWERS IN THE FORECAST WEDNESDAY NIGHT AND THURSDAY. FAIRLY COOL WITH LOWS IN THE UPPER 30S TO UPPER 40S...AND HIGHS MAINLY IN THE 60S. ANOTHER COOL NIGHT THURSDAY NIGHT AS THE COOL HIGH PRESSURE CENTER SETTLES OVER THE DAKOTAS BY FRIDAY MORNING. LOWS IN THE MID TO UPPER 30S TO LOWER 40S. THEN A WARMING TREND INTO THE WEEKEND AS THE WESTERN RIDGE BUILDS BACK INTO THE WESTERN PLAINS. THE NEXT CHANCE FOR WIDESPREAD SHOWERS SHOULD BE TUESDAY. THE WESTERN RIDGE WILL BECOME MORE ZONAL OVER THE WEEKEND...THEN SOUTHWEST FLOW ALOFT RETURNS BY TUESDAY AS AN UPPER LEVEL TROUGH DIVES SOUTHEAST FROM THE GULF OF ALASKA INTO THE WEST COAST...DEVELOPING A SURFACE LOW IN THE LEE OF THE ROCKIES BY TUESDAY MORNING...BRINGING BETTER CHANCES FOR PRECIPITATION NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1250 AM CDT WED SEP 9 2015 INCREASING MID TO UPPER LEVEL CLOUDS AS SURFACE LOW PRESSURE ACROSS NORTHEAST MONTANA AND AN ASSOCIATED WEAK COLD FRONT APPROACHES NORTH DAKOTA TONIGHT INTO WEDNESDAY. FOR THE 06Z TAF VFR IS EXPECTED. AN INCREASE IN CLOUDS AOA 5 THOUSAND AGL IS EXPECTED NORTH HALF OF THE STATE ALONG WITH VCSH FOR KISN-KMOT THROUGH THE PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...AYD LONG TERM...JV AVIATION...NH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
343 AM EDT WED SEP 9 2015 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE REGION TODAY THROUGH TONIGHT...BRINGING OCCASIONAL SHOWERS AND A CHANCE OF A FEW THUNDERSTORMS. COOLER AIR WILL SETTLE IN BEHIND THIS FRONT BY THURSDAY. ANOTHER FRONT WILL MOVE THROUGH THE REGION ON FRIDAY...WITH EVEN COOLER CONDITIONS EXPECTED FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS HIGH PRESSURE SOUTHEAST OF THE OHIO VALLEY LOSES ITS INFLUENCE OVER THE REGION...A TRANSITION IN WEATHER PATTERN IS UNDERWAY. SURFACE OBSERVATIONS AT 07Z PLACE A COLD FRONT ALONG AN AXIS FROM BAD AXE MICHIGAN TO SPRINGFIELD ILLINOIS. WHAT THIS FRONT WILL EVENTUALLY USHER IN OVER THE NEXT DAY OR SO IS A 10-12 DEGREE DROP IN TEMPERATURES...ALONG WITH LESS HUMID CONDITIONS. WHAT THE FRONT LACKS IS MUCH IN THE WAY OF FOCUS...STRENGTH...OR SPEED. IT WILL TAKE MOST OF THE DAY FOR THE SURFACE FRONT TO CROSS THE FORECAST AREA...WHICH WILL ALLOW FOR ANOTHER DAY OF FAIRLY WARM CONDITIONS IN THE SOUTHEASTERN CWA...WITH NOTICEABLY COOLER TEMPERATURES IN THE NORTHWESTERN CWA. WITH FORCING NOT EXPECTED TO BE PARTICULARLY STRONG...COVERAGE AND INTENSITY OF PRECIPITATION IS IN QUESTION. POPS TODAY RANGE FROM 70 (NW) TO 90 (SE) PERCENT...WITH THUNDER SEEMING MOST LIKELY IN THE WARMER AIR IN THE SOUTHEASTERN CWA. PRECIPITATION POTENTIAL APPEARS MAXIMIZED JUST AHEAD OF A (VERY) WEAK SURFACE LOW...WHICH WILL ALLOW FOR A LITTLE EXTRA LIFT AHEAD OF ITS TRACK (ACROSS EASTERN KENTUCKY AND INTO WEST VIRGINIA). ALTHOUGH THE ATMOSPHERE IS FAIRLY MOIST...THE COMBINATION OF POOR MID-LEVEL LAPSE RATES AND COOLING CONDITIONS AT THE SURFACE WILL SEVERELY LIMIT INSTABILITY...WITH MLCAPE VALUES LIKELY TO REMAIN BELOW 1000 J/KG. IN FACT...USING THE RECENT HRRR RUNS AS GUIDANCE...AREAS NORTH OF THE INTERSTATE 71 CORRIDOR MAY NOT SEE MUCH (IF ANY) POTENTIAL FOR THUNDERSTORMS AT ALL. WITH THE WEAK FORCING AND LACK OF ANY NOTABLE WIND SHEAR...STRONG STORMS APPEAR FAIRLY UNLIKELY TODAY. SOME BRIEF HEAVY RAIN COULD OCCUR IN THE SOUTHEASTERN CWA...ESPECIALLY IF THE CELLS DO NOT MOVE QUICKLY. THE AFTERNOON WILL END WITH THE FRONT CLEARING THE SOUTHEASTERN CWA...BUT SOME POST-FRONTAL SHOWERS WILL BE POSSIBLE ELSEWHERE...SO POPS WILL BE MAINTAINED INTO THE EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... A SHORTWAVE WELL BEHIND THE COLD FRONT WILL REMAIN JUST WEST OF THE FORECAST AREA TO START THE DAY ON THURSDAY...MOVING SLOWLY THROUGH THE REGION THROUGH EVENING. THIS WILL ALLOW FOR A CONTINUED CHANCE OF SHOWERS IN THE SOUTHEASTERN SECTIONS OF THE FORECAST AREA...WITH A SLIGHT CHANCE OF A THUNDERSTORM NEAR PEAK HEATING. UNDER THE INFLUENCE OF HIGH PRESSURE...WHICH WILL STRETCH WEST-TO-EAST ACROSS THE SOUTHERN GREAT LAKES...THE NORTHWESTERN HALF OF THE FORECAST AREA IS LIKELY TO REMAIN DRY. NAM/GFS/ECMWF TEMPERATURE PROJECTIONS ARE IN VERY GOOD AGREEMENT...WITH THE WARMEST CONDITIONS (LOWER 80S) IN THE SOUTHWESTERN CWA...AND SLIGHTLY COOLER CONDITIONS (UPPER 70S) IN THE NORTHEASTERN CWA. ATTENTION ON FRIDAY AND GOING INTO THE WEEKEND WILL TURN TOWARD THE DEVELOPMENT OF A LARGE MID-LEVEL TROUGH...WHICH APPEARS TO BE MODELED MORE ENERGETICALLY ON THE 00Z RUNS EARLY THIS MORNING. AHEAD OF THIS TROUGH...ANOTHER COLD FRONT WILL SLICE ACROSS THE UPPER MISSISSIPPI VALLEY ON THURSDAY NIGHT INTO FRIDAY...CLEARING THROUGH THE OHIO VALLEY ON FRIDAY NIGHT INTO SATURDAY. THIS FRONT WILL SHAVE ROUGHLY ANOTHER 10 DEGREES OFF THE TEMPERATURES...LEADING TO AN EXPECTATION FOR BELOW-NORMAL CONDITIONS OVER THE WEEKEND. THE GREATEST POTENTIAL FOR PRECIPITATION APPEARS TO BE FROM FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. THE FRONTAL FORCING THIS TIME MAY BE A LITTLE STRONGER THAN WITH THE SYSTEM TODAY (WEDNESDAY)...BUT INSTABILITY WILL BE ALMOST COMPLETELY LACKING. IF THERE WILL BE A CHANCE FOR THUNDER...IT MAY BE CONFINED TO THE SOUTHERN SECTIONS OF THE FORECAST AREA...AND EVEN THIS IS NOT CERTAIN. POPS WERE INCREASED TO 40-PERCENT ACROSS THE BOARD AS THIS SYSTEM PASSES WNW-TO-ESE THROUGH THE CWA...AND IF THE 00Z ECMWF/GFS PROJECTIONS ARE THE START OF THE TREND...THESE VALUES WILL HAVE TO BE INCREASED FURTHER IN FUTURE FORECASTS. IF THE TROUGH REMAINS IN PLACE...CONDITIONS MAY NOT COMPLETELY DRY OUT ON SATURDAY. SKY GRIDS WERE INCREASED TO ACCOUNT FOR THIS...WITH 20-30 PERCENT POPS MAINTAINED THROUGH THE DAY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... SHOWERS WILL DIMINISH BUT NOT DISAPPEAR SUNDAY AS THE UPPER LOW GRADUALLY LIFTS NORTHEAST. A BROAD UPPER RIDGE IS THEN INDICATED TO PUSH ACROSS MOST OF THE CONUS BY TUESDAY...COUPLING WITH A SURFACE HIGH TO USHER IN A PERIOD OF DRY WEATHER FOR THE OHIO VALLEY REGION. TEMPERATURES WILL VARY NOTABLY WITH RESPECT TO THE UNDULATING UPPER AIR PATTERN. HIGHS ARE FORECAST TO BE NEAR NORMAL IN THE UPPER 70S ON FRIDAY. BELOW NORMAL READINGS IN THE UPPER 60S ARE EXPECTED FOR SATURDAY AND SUNDAY UNDER THE UPPER LOW AND ASSOCIATED CLOUDS AND PRECIP. A RETURN TO NEAR NORMAL UPPER 70S SHOULD OCCUR BY TUESDAY IN WARM ADVECTION ON A SOUTHWEST LOW LEVEL FLOW CIRCULATING AROUND THE HIGH. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... A COLD FRONT WILL SLOWLY MAKE ITS WAY SOUTHEAST THROUGH OUR REGION TODAY. MEANWHILE...MODELS SUGGEST THAT A WEAK WAVE OF LOW PRESSURE WILL TRY TO MOVE WEST TO EAST ALONG THE FRONTAL BOUNDARY NEAR THE OHIO RIVER. THE AIRMASS WILL BECOME INCREASINGLY MOIST AHEAD OF THE FRONT TODAY. THE FORCING WITH THE FRONT...LOW...AND SOME UPPER LEVEL ENERGY IS WEAK. THIS WILL MAKE IT DIFFICULT TO PINPOINT THE BEST TIMING FOR SHOWERS AND EMBEDDED THUNDERSTORMS AT THE TAF SITES. BEST COVERAGE PER HIGH RESOLUTION MODELS SEEM TO FAVOR THE EARLY TO LATE AFTERNOON HOURS WHEN INSTABILITY WILL BE AT ITS MAXIMUM. AS SUCH...HAD ADDED VCTS DESCRIPTORS AT ALL TAF SITES EXCEPT DAYTON WITH TEMPO MVFR CONDITIONS IN SHOWERS. WITH THE INSTABILITY NOT BEING OVERLY GREAT...HAVE NOT GONE WITH TEMPO TSRA ATTM. IT SHOULD BE NOTED THAT WITH THE MOIST AIRMASS...WELL DEVELOPED SHOWERS AND ESPECIALLY ANY THUNDERSTORMS...WILL BE CAPABLE OF LOWER VISIBILITIES IN THE IFR/LIFR CATEGORY...SO AVIATORS SHOULD BE AWARE OF THIS POTENTIAL. FOR TONIGHT...THE FRONTAL BOUNDARY WILL CONTINUE ON ITS WAY TO OUR SOUTHEAST AS THE WEAK WAVE OF LOW PRESSURE BEGINS TO TRANSFER AND DEEPEN OVER THE MID ATLANTIC REGION. PRECIPITATION THREAT SHOULD BE EXITING AWAY FROM THE TAF SITES BETWEEN THE 22Z AND 03Z TIME FRAME. WILL FORECAST VFR CEILINGS/VISIBILITIES OVERNIGHT FOR NOW...BUT THERE IS SOME SUGGESTION THAT MVFR CEILINGS COULD FORM IN THE POST FRONTAL AIRMASS NEAR THE OHIO RIVER TOWARD THURSDAY MORNING. OUTLOOK...MVFR CEILINGS POSSIBLE THURSDAY MORNING. THUNDERSTORMS POSSIBLE FRIDAY INTO FRIDAY EVENING. MVFR CEILINGS POSSIBLE AGAIN FRIDAY NIGHT INTO SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
304 AM CDT WED SEP 9 2015 .DISCUSSION... SURFACE OBSERVATIONS THIS MORNING SHOW TEMPERATURES AND DEWPOINTS IN THE 66-73 DEGREE RANGE WHICH IS SEVERAL DEGREES HIGHER THAN YESTERDAY AT THIS TIME. CLOUD COVER IS ALSO INCREASING EARLY THIS MORNING AS DEEPER MOISTURE...CHARACTERIZED BY PWATS AROUND 1.85 INCHES PER 00Z RAOBS AT BHM AND ATL...CONTINUES TO ADVECT NORTHWESTWARD INTO THE MID STATE. IN FACT...LATEST RADAR IMAGERY SHOWS LIGHT SHOWERS ALREADY DEVELOPING ACROSS NORTH ALABAMA AND SOUTHERN TENNESSEE ON THE LEADING EDGE OF THIS DEEPER MOISTURE. LATEST HRRR MODEL GUIDANCE EXPANDS THIS ACTIVITY THROUGHOUT THE CWA LATER THIS MORNING INTO THE AFTERNOON...WHILE SHOWERS/STORMS CURRENTLY APPROACHING THE MISSISSIPPI RIVER ALSO SPREAD INTO THE AREA AS A UPPER TROUGH AXIS SHIFTS EASTWARD ACROSS THE TENNESSEE VALLEY. THUS WILL CONTINUE LIKELY POPS FOR ALL ZONES...WITH CLOUD COVER AND PRECIPITATION KEEPING HIGHS DOWN IN THE 80S TODAY. SHOWERS AND STORMS WILL CONTINUE INTO TONIGHT AS H5 TROUGH AXIS CONTINUES TO THE EAST...WITH ACTIVITY GRADUALLY SHIFTING SOUTHEAST OUT OF THE CWA FROM THURSDAY INTO THURSDAY NIGHT AS A WEAK COLD FRONT PUSHES SOUTHEASTWARD. A FEW SHOWERS AND MAYBE A THUNDERSTORM APPEAR POSSIBLE ON FRIDAY...BUT A BETTER CHANCE WILL ARRIVE FRIDAY NIGHT INTO SATURDAY AS THE FIRST STRONG COLD FRONT OF METEOROLOGICAL FALL ARRIVES. 00Z GFS/ECMWF CONTINUE TO TREND STRONGER WITH THE UPPER TROUGH THAT WILL FORCE THIS FRONT THROUGH THE AREA...SO HAVE NUDGED POPS UP A TAD FRIDAY NIGHT INTO SATURDAY. THE FIRST TASTE OF FALL IS THEN EXPECTED FOR THE REST OF THE WEEKEND...WITH GFS FINALLY CATCHING ON TO THE ECMWF IN SHOWING DRY WEATHER WITH SIGNIFICANTLY COOLER TEMPERATURES SOME 10 TO 15 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. BASED ON THE LATEST LOCAL MODEL BLEND...WHICH HAS BEEN PERFORMING QUITE WELL OVER THE PAST MONTH...HIGHS IN THE UPPER 60S AND 70S WITH LOWS IN THE UPPER 40S AND 50S ARE EXPECTED FOR SEVERAL DAYS FROM SUNDAY THROUGH AT LEAST TUESDAY. AFTER THAT TIME...MODELS DIFFER ON WHETHER A STRONG COASTAL TROUGH OR POSSIBLE TROPICAL CYCLONE DEVELOPS IN THE WESTERN GULF OF MEXICO...BUT IF THIS OCCURS MOISTURE FROM THIS SYSTEM COULD SPREAD NORTHWARD INTO THE AREA LATER NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 86 70 83 66 / 60 60 50 20 CLARKSVILLE 85 68 82 63 / 60 60 30 10 CROSSVILLE 80 66 77 63 / 70 60 60 40 COLUMBIA 86 68 81 64 / 60 60 60 20 LAWRENCEBURG 86 68 82 65 / 60 60 60 20 WAVERLY 85 68 83 64 / 60 60 40 20 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHAMBURGER
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
458 AM CDT WED SEP 9 2015 .DISCUSSION... REGIONAL RADAR MOSAIC EARLY THIS MORNING SHOWED A COMPLEX OF THUNDERSTORMS LOCATED ALONG THE INTERSTATE 20 CORRIDOR PUSHING SOUTH. EARLY MORNING WATER VAPOR IMAGERY SHOWED THIS COMPLEX WAS AIDED BY A SHORTWAVE TROUGH MOVING ACROSS NORTH TEXAS... WITH 06Z SURFACE ANALYSIS PLACING A COLD FRONT BEHIND THESE THUNDERSTORMS FROM WEST TEXAS INTO CENTRAL OKLAHOMA. EVENING UPPER AIR ANALYSIS SHOWED A BROAD UPPER TROUGH SWINGING ACROSS THE SOUTHERN/CENTRAL PLAINS AND THIS TROUGH WILL HELP PUSH THE COLD FRONT CLOSER TO THE REGION THROUGHOUT TODAY AND TOMORROW. FOR TODAY... THE FT. HOOD VAD WIND PROFILER SHOWS 25 TO 30 KNOTS OF SOUTHERLY INFLOW FEEDING INTO THE THUNDERSTORM COMPLEX OVER NORTH TEXAS EARLY THIS MORNING. THIS SHOULD HELP THESE THUNDERSTORMS MAINTAIN THEMSELVES THROUGH THE REMAINDER OF THE EARLY MORNING HOURS. AS LOW LEVEL INFLOW VEERS AND WEAKENS LATER LATER THIS MORNING HOWEVER... UNCERTAINTY BEGINS TO INCREASE ON HOW FAR SOUTH THIS COMPLEX WILL MAKE IT. SOME HIGH RESOLUTION GUIDANCE SOLUTIONS /NOTABLY THE HRRR AND TEXAS TECH WRF/ SHOWS OUTFLOW FROM THIS COMPLEX REACHING THE BRAZOS VALLEY LATE MORNING/EARLY AFTERNOON. GIVEN RADAR AND SATELLITE TRENDS... THINK AREAS NORTH OF A BRENHAM TO LIVINGSTON LINE APPEAR TO BE THE MOST LIKELY TO SEE RAIN FROM THIS COMPLEX OR ANY ASSOCIATED OUTFLOW AND HIGHLIGHTING THE HIGHEST POPS FOR THE DAY IN THESE AREAS. EVEN IF THE STORMS DISSIPATE BEFORE THE OUTFLOW REACHES THE AREA... DIABATIC HEATING MAY CONTRIBUTE TO ADDITIONAL DEVELOPMENT ALONG IT LATER THIS AFTERNOON. FARTHER SOUTH... CONVECTIVE TEMPERATURES NEAR 90 TODAY WILL ALSO SUPPORT ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT ACROSS THE REMAINDER OF THE REGION... ESPECIALLY AS A SEA BREEZE MOVES FARTHER INLAND. THE UPPER LOW CHURNING OVER THE NORTHERN GULF EARLY THIS MORNING IS EXPECTED TO SHEAR OUT TODAY... DECREASING THE SUBSIDENCE THAT HAS LIMITED MORE ROBUST COVERAGE OVER THE PAST FEW DAYS. IF THE OUTFLOW IS ABLE TO MAKE IT FARTHER SOUTH TODAY THAN ORIGINALLY THOUGHT... POPS ALSO WILL NEED TO BE INCREASED FARTHER SOUTH TODAY. ADDITIONALLY... FORECAST SOUNDINGS FOR HOUSTON THIS AFTERNOON HAVE A DISTINCT INVERTED-V SIGNATURE AND THIS WILL SUPPORT AT LEAST AN ISOLATED GUSTY WIND THREAT FROM ANY THUNDERSTORM THAT DEVELOPS. THE COLD FRONT IS EXPECTED TO MAKE SLOW PROGRESS ACROSS NORTH TEXAS TODAY... AND WITH SOME UNCERTAINTY ON WHERE OUTFLOW FROM TODAY/S THUNDERSTORMS WILL END UP KEEPING POPS HIGHEST TONIGHT ALONG AND NORTH OF A BRENHAM TO CLEVELAND LINE. AS PRECIPITABLE WATER VALUES RISE TO NEAR 2 INCHES LATER TODAY AND INTO TOMORROW... LOCALLY HEAVY RAIN WILL REMAIN POSSIBLE. OTHERWISE... EXPECT HIGHS IN THE UPPER 80S TO LOW 90S TODAY AND LOWS IN THE 70S TO NEAR 80 TONIGHT. THE GREAT PLAINS UPPER TROUGH WILL CONTINUE TO SWING EAST TOWARDS THE GREAT LAKES ON THURSDAY... WITH ITS AXIS EXTENDING OVER THE REGION. THE COLD FRONT WILL MAKE MORE PROGRESS INTO/ STALL SOMEWHERE ACROSS CENTRAL TEXAS ON THURSDAY AND THIS WITH ADDED LIFT FROM A 50-60 KNOT UPPER LEVEL JET STREAK APPROACHING FROM WEST TEXAS WILL KEEP SCATTERED TO NUMEROUS THUNDERSTORMS IN THE FORECAST ON THURSDAY AND FRIDAY. HIGHS TO END THE WEEK WILL BE NEAR NORMAL IN THE MID TO UPPER 80S. HEADING INTO THE WEEKEND... A STRONG SHORTWAVE TROUGH ROTATING AROUND THE BASE OF THE BROAD UPPER TROUGH FRIDAY/SATURDAY WILL SEND A SECONDARY... STRONGER FRONT INTO THE REGION. THIS FRONT LOOKS TO PUSH THROUGH THE REGION SOMETIME ON SATURDAY WITH MUCH DRIER AIR FILTERING INTO THE AREA BEHIND IT. PRECIPITABLE WATER VALUES WILL FALL THROUGHOUT THE DAY ON SATURDAY... BOTTOMING OUT UNDER ONE INCH ON SUNDAY. THIS WILL ALLOW RAIN CHANCES TO TAPER OFF FROM NORTH TO SOUTH DURING THE DAY ON SATURDAY AND PROVIDE WHAT APPEARS TO BE A VERY PLEASANT SUNDAY IN THE MAKING. DRIER AIR WILL ALLOW FOR OVERNIGHT LOW TEMPERATURES TO POSSIBLY FALL INTO THE 60S SUNDAY... WITH HIGHS IN THE LOW TO MID 80S. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW THE DEVELOPMENT OF A COASTAL TROUGH/SURFACE LOW OFF MEXICO/DEEP SOUTH TEXAS HEADING INTO THE BEGINNING OF NEXT WEEK. WHILE STILL OFFERING SOMEWHAT DIFFERENT SOLUTIONS... THE GFS AND THE EUROPEAN BOTH ADVERTISE A GOOD SLUG OF TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE MAKING ITS WAY BACK INTO THE REGION /GFS PWATS INCREASE FROM LESS THAN ONE INCH MONDAY TO NEARLY 2 INCHES ON TUESDAY/ HEADING INTO THE MIDDLE OF NEXT WEEK. SHOWER AND THUNDERSTORM CHANCES WILL RETURN AS THIS SYSTEM EJECTS NORTHWARD TOWARDS THE TEXAS COAST... AND WILL NEED TO CONTINUE TO MONITOR FOR THE POTENTIAL OF HEAVY RAIN. HUFFMAN && .MARINE... LIGHT TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH FRIDAY. PERIODS OF UNSETTLED WEATHER CAN BE EXPECTED...ESPECIALLY THURSDAY THROUGH SATURDAY...AS UPPER LEVEL DISTURBANCES INTERACT WITH DEEPER MOISTURE IN THE AREA. WINDS/SEAS WILL BE HIGHER IN AND NEAR STORMS. A WEAK FRONTAL BOUNDARY WILL PUSH INTO THE WATERS LATE FRIDAY NIGHT OR SATURDAY MORNING WITH NORTHEAST WINDS IN ITS WAKE. A WEAK TROUGH OF LOW PRESSURE WILL DEVELOP NEAR THE LOWER TEXAS COAST EARLY NEXT WEEK AND THIS FEATURE WILL BRING PERIODS OF SHRA/TSRA AND A PROLONGED PERIOD OF E-SE WINDS TO THE UPPER TEXAS COASTAL WATERS. 43 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 92 75 89 74 89 / 60 50 60 30 40 HOUSTON (IAH) 91 75 89 74 87 / 40 30 60 40 50 GALVESTON (GLS) 90 81 89 79 85 / 30 30 60 50 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...14 AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
434 AM CDT WED SEP 9 2015 .SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR SATELLITE IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN MEXICO AND A 500MB LOW OVER THE WESTERN GULF OF MEXICO. BROWNSVILLE RADAR SHOWS VERY ISOLATED ACTIVITY ACROSS THE LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS CONVECTION WILL INCREASE ACROSS THE GULF WATERS LATER THIS MORNING. BRO SOUNDING FROM TUESDAY EVENING INDICATES PRECIPITABLE WATER VALUES OF 2.02 INCHES. MOSTLY CLEAR SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS MORNING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS. THE COMBINATION OF THE 500MB LOW ACROSS THE WESTERN GULF OF MEXICO AND A FRONT MOVING SOUTH OVER CENTRAL TEXAS WILL ALLOW LOW TO MID LEVEL MOISTURE TO INCREASE ACROSS DEEP SOUTH TEXAS THROUGH THE FORECAST PERIOD. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. THE LATEST HRRR/GFS AND ECMWF SUGGEST AN ACTIVE SEA BREEZE TODAY WHILE THE MET REMAINS GENERALLY DRY. WILL LEAN TOWARDS THE WETTER MAV/ECMWF MOS POPS FOR TODAY. DEEPER MOISTURE SHOULD SUPPORT MORE ACTIVITY ACROSS THE AREA ON THURSDAY...ESPECIALLY ACROSS THE COASTAL WATERS AND THE RANCHLANDS. WILL BLEND TOWARDS THE WETTER NAM/ECMWF FOR POPS AREA WIDE FOR THURSDAY. ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY AND THURSDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY THOSE WITH A HISTORY OF FLOODING. HIGH TEMPERATURES TODAY WILL RANGE FROM THE LOWER 90S NEAR THE COAST TO AROUND 100 ACROSS THE UPPER VALLEY. HIGH TEMPERATURES WILL BE A FEW DEGREES LOWER ON THURSDAY DUE TO THE INCREASE IN CLOUDS AND RAIN CHANCES. LOW TEMPERATURES TONIGHT WILL GENERALLY BE IN THE UPPER 70S TO AROUND 80. .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...RATHER BUSY LONG TERM PORTION OF THE FORECAST ANTICIPATED. DEEP TROPICAL MOISTURE (PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES) WILL COMBINE WITH THE FRIDAY NIGHT PASSAGE OF A WEAK COLD FRONT...AND THE SUBSEQUENT DEVELOPMENT AND PERSISTENCE OF AN INVERTED SURFACE TROUGH OF LOW PRESSURE ALONG THE LOWER TEXAS COAST AFTERWARDS. WITH PERSISTENT 500 MB TROUGHINESS ALONG THE TEXAS COASTLINE IN ASSOCIATION WITH A CLOSED 500 MB LOW PRESSURE SYSTEM OVER THE GREAT LAKES REGION...DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY CAN EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FOR MUCH OF THE FORECAST PERIOD...WITH THE HIGHEST RAIN CHANCES FROM FRIDAY THROUGH SATURDAY...WHEN LOCALLY HEAVY RAINFALL HAS ALSO BEEN INCLUDED IN THE FORECAST. THE MOST INTERESTING ASPECT OF THE LONG TERM FORECAST PERIOD IS THE GFS` INDICATION THAT A WEAK CLOSED AREA OF LOW PRESSURE WILL FORM OVER THE WESTERN GULF OF MEXICO AND MOVE INLAND OVER THE BRO CWFA TOWARDS THE END OF THE FORECAST PERIOD. ANY CLOSED AREA OF LOW PRESSURE...SHOULD IT FORM...WOULD HAVE THE ABILITY TO RADICALLY CHANGE PRECIPITATION AND WIND VALUES ON MONDAY AND TUESDAY...AND THIS WILL NEED TO BE MONITORED BY SUCCESSIVE SHIFTS THROUGH THE NEXT FEW DAYS. && .MARINE...NOW THROUGH THURSDAY...BUOY DATA AND OBSERVATION PLATFORMS ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN 8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A WEAK PRESSURE GRADIENT OVER THE WESTERN GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND LOW TO MODERATE SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS. THURSDAY NIGHT THROUGH TUESDAY...GENERALLY LIGHT TO MODERATE WINDS AND LOW TO MODERATE SEAS ARE EXPECTED THROUGH THE PERIOD AS WEAK LOW PRESSURE PERSISTS OVER THE WESTERN GULF OF MEXICO AND A COLD FRONT INTRUDES INTO THE LOWER TEXAS COASTAL WATERS. WEAK CLOSED LOW PRESSURE MAY DEVELOP ALONG THE LOWER TEXAS COAST TOWARDS THE END OF THE FORECAST PERIOD PER ONE WEATHER FORECAST MODEL...BUT THE STRONGER WINDS AND HIGHER SEAS INDICATED IN ASSOCIATION WITH THE LOW PRESSURE DEVELOPMENT HAVE NOT BEEN INCLUDED IN THE FORECAST AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 92 80 91 79 / 30 20 30 20 BROWNSVILLE 93 79 93 79 / 30 20 30 20 HARLINGEN 96 78 95 78 / 30 20 30 20 MCALLEN 98 80 97 78 / 20 10 20 20 RIO GRANDE CITY 100 78 98 77 / 10 10 30 20 SOUTH PADRE ISLAND 87 82 88 80 / 30 30 40 30 && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV SHORT TERM...CACERES-63 LONG TERM...TOMASELLI-66
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
119 AM CDT WED SEP 9 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS PREVAIL OVER DEEP SOUTH TEXAS EARLY THIS MORNING. VFR CONDITIONS EXPECTED TO CONTINUE THROUGH MID MORNING. LOW TO MID LEVEL MOISTURE WILL INCREASE ACROSS THE AREA TODAY AS A 500MB LOW MOVES ACROSS THE WESTERN GULF OF MEXICO. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. LIGHT SOUTHEAST WINDS OVERNIGHT WILL BECOME MODERATE LATER THIS MORNING WITH GUSTS AROUND 20 KNOTS IN THE AFTERNOON. && .PREV DISCUSSION... /ISSUED 636 PM CDT TUE SEP 8 2015/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE MOSTLY CLEAR SKIES ACROSS THE CWA EARLY THIS EVENING. EXPECT VFR CONDITIONS TO PREVAIL THE REST OF THE EVENING INTO EARLY WED MORNING AS NORTHERLY WINDS ALOFT CONTINUE TO PROVIDE SUBSIDENCE ACROSS THE RIO GRANDE VALLEY. A 500MB LOW ACROSS THE NORTH CENTRAL GULF OF MEXICO WILL MOVE ACROSS THE WESTERN GULF OF MEXICO WEDNESDAY. THIS WILL ALLOW LOW TO MID LEVEL MOISTURE TO INCREASE ACROSS THE COASTAL SECTIONS OF THE CWA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND WED AFTERNOON. PREV DISCUSSION... /ISSUED 300 PM CDT TUE SEP 8 2015/ SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AN ACTIVE SEA BREEZE IS MOVING SLOWLY INLAND THIS AFTERNOON. THE HRRR SUGGESTS THAT IT WILL PUSH INTO THE MID VALLEY. DRIER AIR IS STILL IN PLACE FARTHER WEST. SKIES SHOULD BECOME MOSTLY CLEAR TONIGHT. WV IMAGERY SHOWS A MID LEVEL CIRCULATION SOUTH OF LOUISIANA...WHICH IS PROGGED TO DRIFT SOUTHWEST TOWARD THE AREA. THUS...LOOK FOR CONTINUED UNSETTLED CONDITIONS OVER THE GULF...WITH A FEW SHOWERS TRANSLATING FARTHER WEST OVER THE COAST TONIGHT. THE NAM SHOWS DRIER AIR AGAIN OUT WEST ON WEDNESDAY...SO WILL ANTICIPATE SIMILAR CONDITIONS AS TODAY WITH MAYBE A LITTLE MORE ACTIVITY OVER THE COASTAL AREAS. THE MOISTURE POOLING ALONG AND AHEAD OF A FRONT MOVING SOUTH OVER CENTRAL TEXAS WILL NOT BE FAR ENOUGH SOUTH TO CAUSE A MAJOR PROBLEM IN THE SHORT TERM...EXCEPT PERHAPS FOR A FEW SHOWERS OVER THE FAR NORTHWEST... ZAPATA COUNTY...WEDNESDAY NIGHT. LONG TERM /THURSDAY THROUGH TUESDAY/... H5 TROUGH REMAINS BOTTLED BETWEEN 2 RIDGES...WITH THE AXIS REMAINING TO THE EAST ON THURSDAY. THIS WILL KEEP THE REGION ON THE DRIER WEST SIDE THURSDAY AND INTO FRIDAY. FRIDAY BRINGS THE TROUGH AXIS WESTWARD AS THE OVERALL TROUGH DEEPENS. AN INCREASE IN MOISTURE FROM THE SOUTH WILL BEGIN TO RAMP UP POPS LATER FRIDAY AFTERNOON. GOOD DEEP MOISTURE AND INSTABILITY COMBINES ON SATURDAY FOR A GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS. SUNDAY INTO MONDAY A WEAK COLD FRONT TRIES TO MOVE SOUTHWARD INTO SOUTH TEXAS. THE MAIN ISSUE IS SOUTHWARD MOVING DRIER AIR AND HOW FAR SOUTH IT WILL REACH...CLASHING WITH GULF MOISTURE MOVING BACK TO THE NORTH. CONTINUING WITH A GOOD CHANCE FOR THUNDERSTORMS BOTH DAYS AS INSTABILITY REMAINS DECENT. QUESTION MARKS CROP UP STARTING EARLY NEXT WEEK AS MODELS DIFFER ON WHAT HAPPENS TO THE REMNANTS OF THE FRONT. NEEDLESS TO SAY...A DEGRADING FRONT HOVERING IN THE WESTERN GULF NEEDS TO HAVE A CLOSE EYE KEPT ON IT. FOR NOW...THE LOCALIZED INSTABILITY RAIN CHANCES CONTINUE TUESDAY INTO WEDNESDAY...ESPECIALLY CLOSER TO THE COAST...AS WE MOVE INTO OUR CLIMATOLOGICALLY WETTEST WEEK OF THE ENTIRE YEAR. MARINE... A WEAK PRESSURE GRADIENT WILL CAUSE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND LOW TO MODERATE SEAS TO PERSIST ALONG THE LOWER TEXAS COAST. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 63
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
702 AM CDT WED SEP 9 2015 ...Updated for aviation discussion... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT WED SEP 9 2015 The main forecast challenge for early this morning is areas of fog, and or stratus and how dense. Moist weak northeasterly upslope flow and with clear skies is allowing for good radiational cooling, and causing areas of ground fog to develop and some stratus. Will carry areas of fog in most areas this morning, but may need a dense fog advisory in places especially near and west of Dodge City where the NAM and the RAP model shows the highest boundary layer relative humidity. The HRRR model also shows patchy dense fog in the Garden City area. After the fog burns off by mid morning, expect clearing skies and highs in the mid 80s. A surface high pressure ridge will move east while a trough of low pressure develops in the lee of the Rockies. Light and variable winds this morning will become southeast to southerly at 10 mph with 10 to 20 mph far west. For tonight, expect mainly clear skies. A few thunderstorms could develop late across the I-70 corridor as a jet streak moves in. Will carry some small chances for rainfall, towards dawn. Overnight lows will be in the lower 60s with light southeast winds becoming south around 8 to 12 mph. .LONG TERM...(Thursday THROUGH Tuesday) ISSUED AT 339 AM CDT WED SEP 9 2015 For Thursday, an upper level shortwave trough in northwest flow aloft will move across western Kansas pushing a cold front to near Hays to Garden City and Elkhart by late afternoon. Ahead of the cold front, warmer and moist south winds of 15 to 25 mph, will push highs to around 90. Most models have thunderstorms developing by afternoon ahead of the cold front, with a possible MCS (Mesoscale Convective Complex) developing near and east of Dodge City by late afternoon and evening. The cold front will continue to push across western Kansas overnight with numerous thunderstorms developing. Some low stratus is also suggested towards dawn behind the cold front. Will carry around 50 percent chances in the afternoon and evening with lesser chances north of Garden City where dewpoints are much lower. Forecast instability is around 2000-3000 J/KG, but the NAM is much higher and with dewpoints in the upper 60s. With 30kt at mid levels and around 50 to 60kt aloft there could be some severe thunderstorms with large hail from quarter to half dollar size, and strong winds over 60 mph. For Friday into next Tuesday, a dry period is forecast. A large upper level trough will continue to dig into the Upper Midwest and Mississippi Valley with much cooler surface high pressure moving into the Plains. Highs on Friday and Saturday will be in the mid to upper 70s. As the upper trough moves away from the region Sunday into Tuesday, a warming trend will move back into the High Plains with highs in the low 80s on Sunday, then mid to upper 80s on Monday and Tuesday. Overnight lows will be in the 50s into Sunday morning, the gradually warm to 60 to 65 degrees on Monday and Tuesday morning. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Thursday MORNING) ISSUED AT 659 AM CDT WED SEP 9 2015 Weak surface high pressure will move off to the east and be replaced by a surface trough in the lee of the Rockies. This will result in light winds becoming south at 5 to 10 mph this afternoon. Dense fog this morning at KDDC/KGCK will rapidly clear by 15z with daytime heating, leaving VFR conditions for the remainder of the period. && .PRELIMINARY POINT TEMPS/POPS... DDC 85 62 89 60 / 0 10 40 40 GCK 85 61 90 59 / 0 0 30 30 EHA 87 63 91 60 / 10 10 20 20 LBL 86 62 92 61 / 0 10 30 40 HYS 87 61 89 60 / 0 20 30 30 P28 85 63 89 64 / 0 10 20 50 && .DDC Watches/Warnings/Advisories... Dense Fog Advisory until 9 AM CDT /8 AM MDT/ this morning for KSZ043>045-061>066-074>081-084>090. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Finch
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1019 AM EDT WED SEP 9 2015 .SYNOPSIS... SUMMER LIKE HEAT WILL BE IN PLACE TODAY WITH SCATTERED THUNDERSTORMS...MOST NUMEROUS ALONG THE COAST. CLOUDS AND RAIN CHANCES THEN INCREASE LATE IN THE WEEK WITH THE SLOW APPROACH OF A COLD FRONT. THIS BOUNDARY MAY NOT PUSH THROUGH UNTIL MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 10 AM WEDNESDAY...THE SHORTWAVE MOVING UP THE CAROLINA COAST IS PRODUCING A LINE OF SHOWERS AND THUNDERSTORMS THAT IS QUICKLY MOVING ACROSS SOUTHEAST NORTH CAROLINA. THE ATMOSPHERE CONTINUES TO BE VERY MOIST WITH PRECIPITABLE WATER AROUND 2 INCHES ALONG THE COAST. THE 12 UTC HRRR IS SHOWING THE INITIAL BAND OF CONVECTION SHIFTING TO THE NORTHEAST WITH ADDITIONAL CONVECTION DEVELOPING AROUND 15 UTC ALONG OUR ENTIRE COAST BUT QUICKLY ENDING BY MID-AFTERNOON AS THE SUBSIDENCE AND SLIGHTLY DRIER AIR WORKS ITS WAY BEHIND THE SHORTWAVE. WITH WARMER TEMPERATURES ALOFT AND CLEARING SKIES WILL PUSH TEMPERATURES INTO THE LOWER 90S INLAND WITH UPPER 80S ON THE COAST. THIS IS STILL 5 OR MORE DEGREES AWAY FROM RECORDS. WITH DEWPOINTS REMAINING IN THE LOWER TO MID 70S HEAT INDEX VALUES SHOULD REACH 100 DEGREES ACROSS PARTS OF THE PEE DEE REGION. TONIGHT ANOTHER UPPER DISTURBANCE TAKING A MORE INLAND TRACK COULD SPREAD EVENING SHOWERS AND STORMS ACROSS THE I-95 CORRIDOR. I HAVE NOT GONE TOO HIGH WITH POPS HOWEVER GIVEN THE COOLING/STABILIZING BOUNDARY LAYER AND THE BEST LIFT WITH THE DISTURBANCE EXPECTED TO PASS ACROSS CENTRAL AND WESTERN NORTH CAROLINA. AS LOW LEVEL WINDS TURN SOUTHWESTERLY A MODEST LOW LEVEL JET SHOULD DEVELOP WITH 975 MB (1000 FOOT AGL) WINDS INCREASING TO 20-25 KT. THIS SHOULD HELP KEEP A STRONG NOCTURNAL INVERSION FROM DEVELOPING AND LOWS SHOULD ONLY FALL TO 72-75 INLAND AND 75-78 AT THE COAST...ABOUT 7 DEGREES ABOVE NORMAL FOR THE DATE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... PREFRONTAL TROUGH MOVES INTO THE CAROLINAS AND STALLS ON THURSDAY. AHEAD OF THIS FEATURE THERE SHOULD BE AMPLE MOISTURE FOR AT LEAST SCATTERED CONVECTIVE COVERAGE. MID LEVEL FORCING IN THE FORM OF VORT MAXES COME LATE IN THE DAY AND AT NIGHT PREVENTING THE NORMAL DIURNAL DYING OFF OF RADAR COVERAGE EVEN THOUGH DEEP CONVECTION MAY BE HARDER TO COME BY DUE TO THE DECREASE IN INSTABILITY. THIS BOUNDARY WEAKENS AND MOVES OFFSHORE BY FRIDAY AND WAS PREVIOUSLY TO BE REPLACED BY A LEGITIMATE COLD FRONT. THIS FRONT NOW APPEARS SLOWER LEAVING NOT MUCH IN THE WAY OF SURFACE FEATURES IN PLACE LOCALLY. FURTHER COMPLICATING FRIDAY FORECAST IS THE DIFFERENCE IN TIMING AMONGST MODELS WITH RESPECT TO SOME MID LEVEL IMPULSES. IN THE END DID NOT MAKE MUCH CHANGE AND WILL ONCE AGAIN CARRY CHANCE POPS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY... IMPRESSIVELY DEEP UPPER TROUGH DRIVES COLD FRONT INTO THE COASTAL PLAIN ON SATURDAY. BEING ALIGNED WITH THE FLOW ALOFT IT WILL STALL ON SUNDAY. SATURDAY OFFERS THE DEEPEST MOISTURE AND WILL LIKELY PAN OUT BEING A VERY UNSETTLED DAY WITH PERHAPS NUMEROUS SHOWERS AND IF THE DIURNAL TIMING IS RIGHT STRONGER THUNDERSTORMS. MODELS AT SOME ODDS REGARDING THE DEPTH AND TILT OF THE UPPER WAVE AND UNTIL IT ENTERS THE UPPER AIR NETWORK ITS HARD TO SPECULATE WHICH IS CORRECT. ON SUNDAY THE DEEP MOISTURE GETS SHUNTED OFFSHORE BUT SOME LOW LEVEL MOISTURE ALONG THE BOUNDARY WILL STILL CALL FOR SOME LOW RAIN CHANCES MAINLY ALONG THE COAST. COOLER AND DRYER AIR NOW APPEARS TO ARRIVE FASTER AND SHOULD BE ADVECTING IN MODERATELY STRONGLY BY MONDAY. COOLER WEATHER WILL LAST INTO TUESDAY AS THE CENTER OF THE LARGE HIGH BUILDS TO OUR NORTH. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...SHOWERS ARE MOVING TOWARD THE MYRTLES AND THE HRRR MODEL INITIALIZED WELL WITH THIS. ONLY A LITTLE BIT OF HEATING TODAY WILL KICK OFF MORE SHOWERS AS THE LFC IS FAIRLY LOW. LOOK FOR CONVECTION TO MOVE INTO ILM BY MID MORNING WITH THUNDER A DECENT BET. MAINLY MVFR CEILINGS WITH TEMPO IFR VISIBILITIES IN THE HEAVIER RAIN. INLAND...DENSE FOG WILL PERSIST THROUGH AT LEAST 14Z WITH GRADUAL IMPROVEMENT TO VFR BY 15-16Z. SOME CONVECTION WILL ALSO MOVE INTO THIS REGION IN THE AFTERNOON...HOWEVER COVERAGE WILL NOT BE A WIDESPREAD AS THE COAST WHICH WILL HAVE THE RESULTANT BOUNDARY TO WORK WITH. EXTENDED OUTLOOK...SCATTERED CONVECTION ON THURSDAY WITH POSSIBLE NUMEROUS STORMS FRIDAY AND SATURDAY. STORMS ENDING SUNDAY MORNING WITH COOLER CONDITIONS INTO MONDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 10 AM WEDNESDAY...SOUTH-SOUTHWEST WINDS OF 10 KTS WITH SEAS OF 2 TO 2.5 FEET THIS MORNING ARE OCCURRING OVER THE COASTAL WATERS. HIGH PRESSURE WILL SLOWLY LESSEN ITS IMPACT BY THIS EVENING AS A COLD FRONT WELL TO THE WEST MOVES CLOSER TO THE CAROLINAS. WINDS ARE EXPECTED TO SHIFT MORE TO THE SOUTHWEST AND INCREASE TO 10 TO 15 KNOTS. SEAS WILL GRADUALLY INCREASE TO 3 FEET. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... A PREFRONTAL TROUGH WILL BOOST WIND AND SEAS ON THURSDAY. WE ARE NOT ANTICIPATING HEADLINES OR ADVISORIES, BUT ITS BEEN FAIRLY QUIET SO THURSDAY WILL BE MORE UNSETTLED THAN THE PAST FEW DAYS WITH THE ADVENT OF SOME 4 FT SEAS. ON FRIDAY THIS BOUNDARY MOVES OFFSHORE AND WEAKENS IF NOT DISSIPATE ALTOGETHER. THE 20KT GUSTINESS SHOULD DROP OUT OF THE FORECAST AS WILL ANY 4 FT WAVES. A COLD FRONT WILL ALSO BE APPROACHING FROM THE NW ON FRIDAY BUT IT NOW LOOKS SLOWER THAN PREVIOUSLY FORECAST. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY... WITH THE SLOWER ARRIVAL OF COLD FRONT ON SATURDAY THE AREA MAY STAY IN AN INCREASED GRADIENT PRE-FRONTAL FLOW REGIME. AS SUCH WIND SPEEDS MAY NEED TO BE RE-EVALUATED AND RAISED ESPECIALLY AS SOME HIGHER MID LEVEL WINDS MAY BE IMPINGING UPON THE AREA. THE UPPER WAVE DRIVING THIS SYSTEM IS FAR FROM BEING SAMPLED BY THE UPPER AIR NETWORK HOWEVER AND SO NO LARGE CHANGES WILL BE MADE AT THIS TIME. SHOULD THINGS KEEP SLOWING DOWN THEN A SW WIND WILL REMAIN ON SUNDAY AS THE BOUNDARY EITHER STALLS ALONG THE COAST OR PERHAPS JUST INLAND. EITHER WAY THE STRONGER GRADIENT WILL HAVE PUSHED FURTHER OFFSHORE AND THE POSSIBILITY OF HIGHER WINDS AND SEAS THAN THE CURRENT FORECAST ALONG WITH IT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...HAWKINS/TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...HDL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
642 AM EDT WED SEP 9 2015 .SYNOPSIS... SUMMERLIKE HEAT WILL BE IN PLACE TODAY WITH SCATTERED THUNDERSTORMS...MOST NUMEROUS ALONG THE COAST. CLOUDS AND RAIN CHANCES THEN INCREASE LATE IN THE WEEK WITH THE SLOW APPROACH OF A COLD FRONT. THIS BOUNDARY MAY NOT PUSH THROUGH UNTIL MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 645 AM WEDNESDAY...SURFACE HIGH PRESSURE NORTH OF BERMUDA WILL PROVIDE A WARM AND HUMID AIRMASS TO THE CAROLINAS TODAY STRAIGHT OUT OF THE BAHAMAS. 850 MB TEMP EXPECTED TO HOVER AROUND +18C IS NEAR THE 95TH PERCENTILE FOR CLIMATOLOGICAL READINGS THIS TIME OF YEAR AT CHS. AS A RESULT WE SHOULD SEE HIGH TEMPERATURES RISE INTO THE LOWER 90S INLAND WITH UPPER 80S ON THE COAST. THIS IS STILL 5 OR MORE DEGREES AWAY FROM RECORDS. WITH DEWPOINTS REMAINING IN THE LOWER TO MID 70S HEAT INDEX VALUES SHOULD REACH 100 DEGREES ACROSS PARTS OF THE PEE DEE REGION. AN UPPER DISTURBANCE CURRENTLY MOVING NORTHEASTWARD THROUGH COASTAL SOUTH CAROLINA IS HELPING SUPPORT A CLUSTER OF SHOWERS & THUNDERSTORMS NEAR GEORGETOWN/MURRELLS INLET. THIS DISTURBANCE SHOULD MOVE THROUGH MYRTLE BEACH AFTER SUNRISE...REACHING SE NORTH CAROLINA BY LATE THIS MORNING. HIGH RES MODELS INCLUDING THE NSSL WRF...THE LATEST SEVERAL HRRR RUNS...AND THE ARW AND NMM VERSIONS OF THE WRF ALL SUPPORT THE IDEA OF CONVECTION BECOMING MORE WIDESPREAD ACROSS SE NORTH CAROLINA AROUND 14-15Z (10-11 AM) AS THE UPPER DISTURBANCE ENCOUNTERS AN UNCAPPED AIRMASS WITH SURFACE-BASED CAPE IN EXCESS OF 2000 J/KG. I HAVE INCREASED POPS TO 40-60 PERCENT IN THE CAPE FEAR REGION...WITH POPS ELSEWHERE IN THE 10-30 PERCENT RANGE GIVEN PROBABLE SUBSIDENCE AND MID-LEVEL DRYING BEHIND THE UPPER DISTURBANCE. CONVECTION SHOULD TEND TO MOVE NORTHEASTWARD DURING THE MID TO LATE AFTERNOON...FOLLOWING THE DISTURBANCE INTO FAR-EASTERN NORTH CAROLINA. TONIGHT ANOTHER UPPER DISTURBANCE TAKING A MORE INLAND TRACK COULD SPREAD EVENING SHOWERS AND STORMS ACROSS THE I-95 CORRIDOR. I HAVE NOT GONE TOO HIGH WITH POPS HOWEVER GIVEN THE COOLING/STABILIZING BOUNDARY LAYER AND THE BEST LIFT WITH THE DISTURBANCE EXPECTED TO PASS ACROSS CENTRAL AND WESTERN NORTH CAROLINA. AS LOW LEVEL WINDS TURN SOUTHWESTERLY A MODEST LOW LEVEL JET SHOULD DEVELOP WITH 975 MB (1000 FOOT AGL) WINDS INCREASING TO 20-25 KT. THIS SHOULD HELP KEEP A STRONG NOCTURNAL INVERSION FROM DEVELOPING AND LOWS SHOULD ONLY FALL TO 72-75 INLAND AND 75-78 AT THE COAST...ABOUT 7 DEGREES ABOVE NORMAL FOR THE DATE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... PREFRONTAL TROUGH MOVES INTO THE CAROLINAS AND STALLS ON THURSDAY. AHEAD OF THIS FEATURE THERE SHOULD BE AMPLE MOISTURE FOR AT LEAST SCATTERED CONVECTIVE COVERAGE. MID LEVEL FORCING IN THE FORM OF VORT MAXES COME LATE IN THE DAY AND AT NIGHT PREVENTING THE NORMAL DIURNAL DYING OFF OF RADAR COVERAGE EVEN THOUGH DEEP CONVECTION MAY BE HARDER TO COME BY DUE TO THE DECREASE IN INSTABILITY. THIS BOUNDARY WEAKENS AND MOVES OFFSHORE BY FRIDAY AND WAS PREVIOUSLY TO BE REPLACED BY A LEGITIMATE COLD FRONT. THIS FRONT NOW APPEARS SLOWER LEAVING NOT MUCH IN THE WAY OF SURFACE FEATURES IN PLACE LOCALLY. FURTHER COMPLICATING FRIDAY FORECAST IS THE DIFFERENCE IN TIMING AMONGST MODELS WITH RESPECT TO SOME MID LEVEL IMPULSES. IN THE END DID NOT MAKE MUCH CHANGE AND WILL ONCE AGAIN CARRY CHANCE POPS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY... IMPRESSIVELY DEEP UPPER TROUGH DRIVES COLD FRONT INTO THE COASTAL PLAIN ON SATURDAY. BEING ALIGNED WITH THE FLOW ALOFT IT WILL STALL ON SUNDAY. SATURDAY OFFERS THE DEEPEST MOISTURE AND WILL LIKELY PAN OUT BEING A VERY UNSETTLED DAY WITH PERHAPS NUMEROUS SHOWERS AND IF THE DIURNAL TIMING IS RIGHT STRONGER THUNDERSTORMS. MODELS AT SOME ODDS REGARDING THE DEPTH AND TILT OF THE UPPER WAVE AND UNTIL IT ENTERS THE UPPER AIR NETWORK ITS HARD TO SPECULATE WHICH IS CORRECT. ON SUNDAY THE DEEP MOISTURE GETS SHUNTED OFFSHORE BUT SOME LOW LEVEL MOISTURE ALONG THE BOUNDARY WILL STILL CALL FOR SOME LOW RAIN CHANCES MAINLY ALONG THE COAST. COOLER AND DRYER AIR NOW APPEARS TO ARRIVE FASTER AND SHOULD BE ADVECTING IN MODERATELY STRONGLY BY MONDAY. COOLER WEATHER WILL LAST INTO TUESDAY AS THE CENTER OF THE LARGE HIGH BUILDS TO OUR NORTH. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...SHOWERS ARE MOVING TOWARD THE MYRTLES AND THE HRRR MODEL INITIALIZED WELL WITH THIS. ONLY A LITTLE BIT OF HEATING TODAY WILL KICK OFF MORE SHOWERS AS THE LFC IS FAIRLY LOW. LOOK FOR CONVECTION TO MOVE INTO ILM BY MID MORNING WITH THUNDER A DECENT BET. MAINLY MVFR CEILINGS WITH TEMPO IFR VISIBILITIES IN THE HEAVIER RAIN. INLAND...DENSE FOG WILL PERSIST THROUGH AT LEAST 14Z WITH GRADUAL IMPROVEMENT TO VFR BY 15-16Z. SOME CONVECTION WILL ALSO MOVE INTO THIS REGION IN THE AFTERNOON...HOWEVER COVERAGE WILL NOT BE A WIDESPREAD AS THE COAST WHICH WILL HAVE THE RESULTANT BOUNDARY TO WORK WITH. EXTENDED OUTLOOK...SCATTERED CONVECTION ON THURSDAY WITH POSSIBLE NUMEROUS STORMS FRIDAY AND SATURDAY. STORMS ENDING SUNDAY MORNING WITH COOLER CONDITIONS INTO MONDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 645 AM WEDNESDAY...HIGH PRESSURE NORTH OF BERMUDA WILL BE OUR CONTROLLING WEATHER SYSTEM THROUGH TONIGHT. TODAY`S SOUTH WINDS WILL VEER MORE SOUTHWESTERLY TONIGHT AS A COLD FRONT...CURRENTLY MOVING SE ACROSS ILLINOIS AND WISCONSIN...MOVES INTO WEST VIRGINIA AND KENTUCKY. AN UPPER LEVEL DISTURBANCE CURRENTLY MOVING NORTHEASTWARD ACROSS COASTAL SOUTH CAROLINA WILL SPREAD SCATTERED SHOWERS ALONG THE NORTHEASTERN SOUTH CAROLINA COAST THIS MORNING. LATEST HIGH-RES MODELS INDICATE COVERAGE OF STORMS WILL EXPAND ONCE THE DISTURBANCE REACHES SOUTHEASTERN NORTH CAROLINA LATE THIS MORNING. STEERING WINDS IN THE ATMOSPHERE WILL TEND TO PUSH STORMS NORTHEASTWARD AT 10 MPH...HOWEVER ASSUMING ENOUGH STORMS FORM COLLIDING OUTFLOW BOUNDARIES WILL ULTIMATELY DETERMINE WHERE STORMS MOVE. MARINERS IN THE CAPE FEAR AREA WILL WANT TO KEEP AN EYE ON THE SKY LATE THIS MORNING AND EARLY THIS AFTERNOON. SEAS CURRENTLY AROUND 2 FEET WILL BUILD CLOSER TO 3 FEET LATE THIS AFTERNOON AS WIND SPEEDS INCREASE WITH THE SEABREEZE. SW WINDS WILL INCREASE TO NEAR 15 KT TONIGHT. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... A PREFRONTAL TROUGH WILL BOOST WIND AND SEAS ON THURSDAY. WE ARE NOT ANTICIPATING HEADLINES OR ADVISORIES, BUT ITS BEEN FAIRLY QUIET SO THURSDAY WILL BE MORE UNSETTLED THAN THE PAST FEW DAYS WITH THE ADVENT OF SOME 4 FT SEAS. ON FRIDAY THIS BOUNDARY MOVES OFFSHORE AND WEAKENS IF NOT DISSIPATE ALTOGETHER. THE 20KT GUSTINESS SHOULD DROP OUT OF THE FORECAST AS WILL ANY 4 FT WAVES. A COLD FRONT WILL ALSO BE APPROACHING FROM THE NW ON FRIDAY BUT IT NOW LOOKS SLOWER THAN PREVIOUSLY FORECAST. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY... WITH THE SLOWER ARRIVAL OF COLD FRONT ON SATURDAY THE AREA MAY STAY IN AN INCREASED GRADIENT PRE-FRONTAL FLOW REGIME. AS SUCH WIND SPEEDS MAY NEED TO BE RE-EVALUATED AND RAISED ESPECIALLY AS SOME HIGHER MID LEVEL WINDS MAY BE IMPINGING UPON THE AREA. THE UPPER WAVE DRIVING THIS SYSTEM IS FAR FROM BEING SAMPLED BY THE UPPER AIR NETWORK HOWEVER AND SO NO LARGE CHANGES WILL BE MADE AT THIS TIME. SHOULD THINGS KEEP SLOWING DOWN THEN A SW WIND WILL REMAIN ON SUNDAY AS THE BOUNDARY EITHER STALLS ALONG THE COAST OR PERHAPS JUST INLAND. EITHER WAY THE STRONGER GRADIENT WILL HAVE PUSHED FURTHER OFFSHORE AND THE POSSIBILITY OF HIGHER WINDS AND SEAS THAN THE CURRENT FORECAST ALONG WITH IT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MBB NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
657 AM EDT WED SEP 9 2015 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE REGION TODAY THROUGH TONIGHT...BRINGING OCCASIONAL SHOWERS AND A CHANCE OF A FEW THUNDERSTORMS. COOLER AIR WILL SETTLE IN BEHIND THIS FRONT BY THURSDAY. ANOTHER FRONT WILL MOVE THROUGH THE REGION ON FRIDAY...WITH EVEN COOLER CONDITIONS EXPECTED FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS HIGH PRESSURE SOUTHEAST OF THE OHIO VALLEY LOSES ITS INFLUENCE OVER THE REGION...A TRANSITION IN WEATHER PATTERN IS UNDERWAY. SURFACE OBSERVATIONS AT 07Z PLACE A COLD FRONT ALONG AN AXIS FROM BAD AXE MICHIGAN TO SPRINGFIELD ILLINOIS. WHAT THIS FRONT WILL EVENTUALLY USHER IN OVER THE NEXT DAY OR SO IS A 10-12 DEGREE DROP IN TEMPERATURES...ALONG WITH LESS HUMID CONDITIONS. WHAT THE FRONT LACKS IS MUCH IN THE WAY OF FOCUS...STRENGTH...OR SPEED. IT WILL TAKE MOST OF THE DAY FOR THE SURFACE FRONT TO CROSS THE FORECAST AREA...WHICH WILL ALLOW FOR ANOTHER DAY OF FAIRLY WARM CONDITIONS IN THE SOUTHEASTERN CWA...WITH NOTICEABLY COOLER TEMPERATURES IN THE NORTHWESTERN CWA. WITH FORCING NOT EXPECTED TO BE PARTICULARLY STRONG...COVERAGE AND INTENSITY OF PRECIPITATION IS IN QUESTION. POPS TODAY RANGE FROM 70 (NW) TO 90 (SE) PERCENT...WITH THUNDER SEEMING MOST LIKELY IN THE WARMER AIR IN THE SOUTHEASTERN CWA. PRECIPITATION POTENTIAL APPEARS MAXIMIZED JUST AHEAD OF A (VERY) WEAK SURFACE LOW...WHICH WILL ALLOW FOR A LITTLE EXTRA LIFT AHEAD OF ITS TRACK (ACROSS EASTERN KENTUCKY AND INTO WEST VIRGINIA). ALTHOUGH THE ATMOSPHERE IS FAIRLY MOIST...THE COMBINATION OF POOR MID-LEVEL LAPSE RATES AND COOLING CONDITIONS AT THE SURFACE WILL SEVERELY LIMIT INSTABILITY...WITH MLCAPE VALUES LIKELY TO REMAIN BELOW 1000 J/KG. IN FACT...USING THE RECENT HRRR RUNS AS GUIDANCE...AREAS NORTH OF THE INTERSTATE 71 CORRIDOR MAY NOT SEE MUCH (IF ANY) POTENTIAL FOR THUNDERSTORMS AT ALL. WITH THE WEAK FORCING AND LACK OF ANY NOTABLE WIND SHEAR...STRONG STORMS APPEAR FAIRLY UNLIKELY TODAY. SOME BRIEF HEAVY RAIN COULD OCCUR IN THE SOUTHEASTERN CWA...ESPECIALLY IF THE CELLS DO NOT MOVE QUICKLY. THE AFTERNOON WILL END WITH THE FRONT CLEARING THE SOUTHEASTERN CWA...BUT SOME POST-FRONTAL SHOWERS WILL BE POSSIBLE ELSEWHERE...SO POPS WILL BE MAINTAINED INTO THE EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... A SHORTWAVE WELL BEHIND THE COLD FRONT WILL REMAIN JUST WEST OF THE FORECAST AREA TO START THE DAY ON THURSDAY...MOVING SLOWLY THROUGH THE REGION THROUGH EVENING. THIS WILL ALLOW FOR A CONTINUED CHANCE OF SHOWERS IN THE SOUTHEASTERN SECTIONS OF THE FORECAST AREA...WITH A SLIGHT CHANCE OF A THUNDERSTORM NEAR PEAK HEATING. UNDER THE INFLUENCE OF HIGH PRESSURE...WHICH WILL STRETCH WEST-TO-EAST ACROSS THE SOUTHERN GREAT LAKES...THE NORTHWESTERN HALF OF THE FORECAST AREA IS LIKELY TO REMAIN DRY. NAM/GFS/ECMWF TEMPERATURE PROJECTIONS ARE IN VERY GOOD AGREEMENT...WITH THE WARMEST CONDITIONS (LOWER 80S) IN THE SOUTHWESTERN CWA...AND SLIGHTLY COOLER CONDITIONS (UPPER 70S) IN THE NORTHEASTERN CWA. ATTENTION ON FRIDAY AND GOING INTO THE WEEKEND WILL TURN TOWARD THE DEVELOPMENT OF A LARGE MID-LEVEL TROUGH...WHICH APPEARS TO BE MODELED MORE ENERGETICALLY ON THE 00Z RUNS EARLY THIS MORNING. AHEAD OF THIS TROUGH...ANOTHER COLD FRONT WILL SLICE ACROSS THE UPPER MISSISSIPPI VALLEY ON THURSDAY NIGHT INTO FRIDAY...CLEARING THROUGH THE OHIO VALLEY ON FRIDAY NIGHT INTO SATURDAY. THIS FRONT WILL SHAVE ROUGHLY ANOTHER 10 DEGREES OFF THE TEMPERATURES...LEADING TO AN EXPECTATION FOR BELOW-NORMAL CONDITIONS OVER THE WEEKEND. THE GREATEST POTENTIAL FOR PRECIPITATION APPEARS TO BE FROM FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. THE FRONTAL FORCING THIS TIME MAY BE A LITTLE STRONGER THAN WITH THE SYSTEM TODAY (WEDNESDAY)...BUT INSTABILITY WILL BE ALMOST COMPLETELY LACKING. IF THERE WILL BE A CHANCE FOR THUNDER...IT MAY BE CONFINED TO THE SOUTHERN SECTIONS OF THE FORECAST AREA...AND EVEN THIS IS NOT CERTAIN. POPS WERE INCREASED TO 40-PERCENT ACROSS THE BOARD AS THIS SYSTEM PASSES WNW-TO-ESE THROUGH THE CWA...AND IF THE 00Z ECMWF/GFS PROJECTIONS ARE THE START OF THE TREND...THESE VALUES WILL HAVE TO BE INCREASED FURTHER IN FUTURE FORECASTS. IF THE TROUGH REMAINS IN PLACE...CONDITIONS MAY NOT COMPLETELY DRY OUT ON SATURDAY. SKY GRIDS WERE INCREASED TO ACCOUNT FOR THIS...WITH 20-30 PERCENT POPS MAINTAINED THROUGH THE DAY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... SHOWERS WILL DIMINISH BUT NOT DISAPPEAR SUNDAY AS THE UPPER LOW GRADUALLY LIFTS NORTHEAST. A BROAD UPPER RIDGE IS THEN INDICATED TO PUSH ACROSS MOST OF THE CONUS BY TUESDAY...COUPLING WITH A SURFACE HIGH TO USHER IN A PERIOD OF DRY WEATHER FOR THE OHIO VALLEY REGION. TEMPERATURES WILL VARY NOTABLY WITH RESPECT TO THE UNDULATING UPPER AIR PATTERN. HIGHS ARE FORECAST TO BE NEAR NORMAL IN THE UPPER 70S ON FRIDAY. BELOW NORMAL READINGS IN THE UPPER 60S ARE EXPECTED FOR SATURDAY AND SUNDAY UNDER THE UPPER LOW AND ASSOCIATED CLOUDS AND PRECIP. A RETURN TO NEAR NORMAL UPPER 70S SHOULD OCCUR BY TUESDAY IN WARM ADVECTION ON A SOUTHWEST LOW LEVEL FLOW CIRCULATING AROUND THE HIGH. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... A COLD FRONT WILL SLOWLY MAKE ITS WAY SOUTHEAST THROUGH OUR REGION TODAY. MEANWHILE...MODELS SUGGEST THAT A WEAK WAVE OF LOW PRESSURE WILL TRY TO MOVE WEST TO EAST ALONG THE FRONTAL BOUNDARY NEAR THE OHIO RIVER. THE AIRMASS WILL BECOME INCREASINGLY MOIST AHEAD OF THE FRONT TODAY. THE FORCING WITH THE FRONT...LOW...AND SOME UPPER LEVEL ENERGY IS WEAK. THIS WILL MAKE IT DIFFICULT TO PINPOINT THE BEST TIMING FOR SHOWERS AND EMBEDDED THUNDERSTORMS. BEST COVERAGE PER HIGH RESOLUTION MODELS SEEM TO FAVOR THE PERIOD FROM EARLY AFTERNOON TO THE EARLY EVENING HOURS WHEN INSTABILITY WILL BE AT ITS MAXIMUM. IN THIS UPDATE...IT APPEARS THAT THE THREAT FOR THUNDER WILL OCCUR ALONG AND SOUTHEAST OF THE SLOW MOVING COLD FRONT AND NEAR THE WEAK SFC WAVE. AS SUCH...HAVE KEPT THE VCTS DESCRIPTORS AT THE SOUTHERN TAF SITES OF KCVG/KLUK. OTHERWISE...ALL TAF SITES WILL HAVE THE THREAT FOR MVFR CONDITIONS. IT SHOULD BE NOTED THAT WITH THE MOIST AIRMASS...WELL DEVELOPED SHOWERS AND ESPECIALLY ANY THUNDERSTORMS...WILL BE CAPABLE OF LOWER VISIBILITIES IN THE IFR/LIFR CATEGORY...SO AVIATORS SHOULD BE AWARE OF THIS POTENTIAL. FOR TONIGHT...THE FRONTAL BOUNDARY WILL CONTINUE ON ITS WAY TO OUR SOUTHEAST AS THE WEAK WAVE OF LOW PRESSURE BEGINS TO TRANSFER AND DEEPEN OVER THE MID ATLANTIC REGION. PRECIPITATION THREAT SHOULD BE EXITING AWAY FROM THE TAF SITES BETWEEN 00Z AND 09Z. WILL FORECAST VFR CEILINGS/VISIBILITIES OVERNIGHT FOR THE NORTHERN TAF SITES. IT APPEARS THAT KILN...KCVG...AND KLUK MAY DROP INTO PREDOMINATE MVFR CEILINGS LATE (WHERE IT MAY RAIN THE MOST TODAY) WHERE LOW LEVELS WILL SATURATE THE BEST OVERNIGHT. OUTLOOK...MVFR CEILINGS POSSIBLE THURSDAY MORNING. THUNDERSTORMS POSSIBLE FRIDAY INTO FRIDAY EVENING. MVFR CEILINGS POSSIBLE AGAIN FRIDAY NIGHT INTO SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
ISSUED BY NATIONAL WEATHER SERVICE JACKSON MS 1020 AM CDT WED SEP 9 2015 .DISCUSSION...VISIBLE SATELLITE IMAGERY THIS MORNING SHOWED A DECK OF MOSTLY MID/HIGH CLOUDS STREAMING ACROSS SERN PORTIONS OF THE FORECAST AREA, WITH SUBSTANTIAL BREAKS ACROSS THE REMAINDER OF THE CWA. AS A RESULT, 15Z TEMPS RANGED FROM THE LOW-MID 80S IN AREAS SEEING MORE SUNSHINE TO MID-UPPER 70S OVER MUCH OF THE CUMBERLAND PLATEAU. ISOLATED SHOWERS WERE ONGOING NORTHEAST OF THE METRO AREA FROM PORTLAND TO AROUND CARTHAGE, HOWEVER MOST AREAS REMAIN DRY AT THIS POINT. HEADING THROUGH THE REMAINDER OF THE DAY, THE PRESENCE OF DEEP LAYER MOISTURE (1.82 IN PW NOTED ON 12Z OHX SOUNDING), DEVELOPING WEAK TO MODERATE INSTABILITY, AND AN APPROACHING COLD FRONT WILL PROVIDE INCREASING CONVECTIVE COVERAGE ACROSS THE REGION. THOUGH RELATIVELY WEAK DEEP LAYER SHEAR AND UNIMPRESSIVE LAPSE RATES WILL LIMIT THE THREAT OF STRONG STORMS, THUNDERSTORMS WILL BE POSSIBLE. SOME MINOR TWEAKS WERE MADE TO THE FORECAST TO INDICATE GREATER POPS THIS AFTERNOON THAN THIS MORNING. OTHERWISE, THE INHERITED FORECAST WAS ON TRACK AND NO OTHER ADJUSTMENTS WERE MADE. DL/JAN && .PREV DISCUSSION... /ISSUED 304 AM CDT WED SEP 9 2015/ SURFACE OBSERVATIONS THIS MORNING SHOW TEMPERATURES AND DEWPOINTS IN THE 66-73 DEGREE RANGE WHICH IS SEVERAL DEGREES HIGHER THAN YESTERDAY AT THIS TIME. CLOUD COVER IS ALSO INCREASING EARLY THIS MORNING AS DEEPER MOISTURE...CHARACTERIZED BY PWATS AROUND 1.85 INCHES PER 00Z RAOBS AT BHM AND ATL...CONTINUES TO ADVECT NORTHWESTWARD INTO THE MID STATE. IN FACT...LATEST RADAR IMAGERY SHOWS LIGHT SHOWERS ALREADY DEVELOPING ACROSS NORTH ALABAMA AND SOUTHERN TENNESSEE ON THE LEADING EDGE OF THIS DEEPER MOISTURE. LATEST HRRR MODEL GUIDANCE EXPANDS THIS ACTIVITY THROUGHOUT THE CWA LATER THIS MORNING INTO THE AFTERNOON...WHILE SHOWERS/STORMS CURRENTLY APPROACHING THE MISSISSIPPI RIVER ALSO SPREAD INTO THE AREA AS A UPPER TROUGH AXIS SHIFTS EASTWARD ACROSS THE TENNESSEE VALLEY. THUS WILL CONTINUE LIKELY POPS FOR ALL ZONES...WITH CLOUD COVER AND PRECIPITATION KEEPING HIGHS DOWN IN THE 80S TODAY. SHOWERS AND STORMS WILL CONTINUE INTO TONIGHT AS H5 TROUGH AXIS CONTINUES TO THE EAST...WITH ACTIVITY GRADUALLY SHIFTING SOUTHEAST OUT OF THE CWA FROM THURSDAY INTO THURSDAY NIGHT AS A WEAK COLD FRONT PUSHES SOUTHEASTWARD. A FEW SHOWERS AND MAYBE A THUNDERSTORM APPEAR POSSIBLE ON FRIDAY...BUT A BETTER CHANCE WILL ARRIVE FRIDAY NIGHT INTO SATURDAY AS THE FIRST STRONG COLD FRONT OF METEOROLOGICAL FALL ARRIVES. 00Z GFS/ECMWF CONTINUE TO TREND STRONGER WITH THE UPPER TROUGH THAT WILL FORCE THIS FRONT THROUGH THE AREA...SO HAVE NUDGED POPS UP A TAD FRIDAY NIGHT INTO SATURDAY. THE FIRST TASTE OF FALL IS THEN EXPECTED FOR THE REST OF THE WEEKEND...WITH GFS FINALLY CATCHING ON TO THE ECMWF IN SHOWING DRY WEATHER WITH SIGNIFICANTLY COOLER TEMPERATURES SOME 10 TO 15 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. BASED ON THE LATEST LOCAL MODEL BLEND...WHICH HAS BEEN PERFORMING QUITE WELL OVER THE PAST MONTH...HIGHS IN THE UPPER 60S AND 70S WITH LOWS IN THE UPPER 40S AND 50S ARE EXPECTED FOR SEVERAL DAYS FROM SUNDAY THROUGH AT LEAST TUESDAY. AFTER THAT TIME...MODELS DIFFER ON WHETHER A STRONG COASTAL TROUGH OR POSSIBLE TROPICAL CYCLONE DEVELOPS IN THE WESTERN GULF OF MEXICO...BUT IF THIS OCCURS MOISTURE FROM THIS SYSTEM COULD SPREAD NORTHWARD INTO THE AREA LATER NEXT WEEK. SHAMBURGER && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 86 70 83 66 / 60 60 50 20 CLARKSVILLE 85 68 82 63 / 60 60 30 10 CROSSVILLE 80 66 77 63 / 70 60 60 40 COLUMBIA 86 68 81 64 / 60 60 60 20 LAWRENCEBURG 86 68 82 65 / 60 60 60 20 WAVERLY 85 68 83 64 / 60 60 40 20 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1029 AM CDT WED SEP 9 2015 .UPDATE... MORNING FORECAST UPDATE... && .DISCUSSION... LATEST RADAR TRENDS SHOW SHOWER ACTIVITY LEFT OVER FROM A MORNING MCS OVER N TX. MCS HAS FOR THE MOST PART JUST FALLEN APART WITH OUTFLOW PUSHING SOUTH IN THE AREA. MAIN QUESTION WILL BE HOW MUCH RE-DEVELOPMENT OF CONVECTION OCCURS ALONG THE OUTFLOW. UPPER LEVEL ANALYSIS HAS UPPER RIDGE OVER THE S ROCKIES WITH NW/N FLOW ALOFT OVER SE TX THAT WRAPS AROUND AN UPPER LOW OVER THE N GULF. LOWER 500MB HEIGHTS AND PRECIP WATER VALUES AROUND 1.8-2 INCHES SUGGEST ISO TO SCT SHRA/TSRA ACTIVITY AS TEMPS WARM TOWARDS 90F MARK. RADAR ALREADY SHOWS SCT ACTIVITY OFF THE COAST AND JUST INLAND. UPDATED RAIN CHANCES TO PRETTY MUCH 40 PRECENT AREAWIDE TO ACCOUNT FOR SCT SHRA/TSRA ACTIVITY. THERE EVEN MAY BE AN ISO STRONG STORM SINCE CRP/LCH SOUNDINGS SHOW AROUND 2000 J/KG OF CAPE THIS MORNING. THINK THE MAIN THREATS WILL BE BRIEF HEAVY RAINFALL AND GUSTY WINDS WITH FREEZING LEVELS QUITE HIGH. CLOUD COVER MAY KEEP TEMPS IN THE 80S BUT THERE COULD BE ENOUGH BREAKS TO REACH LOW 90S. MAIN CHANGES TO THE FORECAST WERE TO UPDATE POP/WX/T/TD FORECAST BASED ON CURRENT TRENDS. 39 && .PREV DISCUSSION... /ISSUED / DISCUSSION... SEE 12Z AVIATION DISCUSSION. AVIATION... PRECIP OVER N TX CONTINUES TO SAG SOUTH AND IF THE LINE HOLDS TOGETHER...IT SHOULD ARRIVE AT NORTHERN TAF SITES AROUND 15Z. SHORT TERM GUIDANCE SUGGESTS THAT THE AREA WILL WEAKEN AND IR IMAGERY SHOWS SOME SLIGHT WARMING OF THE CLOUD TOPS. KGRK VWP STILL SHOWING 30 KTS OF INFLOW INTO THE LINE WHICH SHOULD HELP SUSTAIN THE LINE. PW VALUES WILL EXCEED 2.00 INCHES OVER MUCH OF THEN AREA TODAY SO SCT SHRA/ISO TSRA WILL BE POSSIBLE AT ALL TAF SITES TODAY. TIMING IS THE TRICKY PART. TOOK A BLEND OF THE NAM... GFS AND THE ECMWF WITH BEST RAIN CHANCES AT THE HOUSTON TERMINALS BETWEEN 18-03Z. NCEP 4 KM WRF IS VERY AGGRESSIVE WITH PRECIP BETWEEN 09-12Z THURSDAY OVER THE SOUTHERN TAF SITES. NOT SURE IF IT IS ON TO SOMETHING BUT ADDED VCSH FOR KSGR...KHOU...KLBX AND KGLS FOR EARLY THURSDAY MORNING. 43 PREV DISCUSSION... /ISSUED / DISCUSSION... REGIONAL RADAR MOSAIC EARLY THIS MORNING SHOWED A COMPLEX OF THUNDERSTORMS LOCATED ALONG THE INTERSTATE 20 CORRIDOR PUSHING SOUTH. EARLY MORNING WATER VAPOR IMAGERY SHOWED THIS COMPLEX WAS AIDED BY A SHORTWAVE TROUGH MOVING ACROSS NORTH TEXAS... WITH 06Z SURFACE ANALYSIS PLACING A COLD FRONT BEHIND THESE THUNDERSTORMS FROM WEST TEXAS INTO CENTRAL OKLAHOMA. EVENING UPPER AIR ANALYSIS SHOWED A BROAD UPPER TROUGH SWINGING ACROSS THE SOUTHERN/CENTRAL PLAINS AND THIS TROUGH WILL HELP PUSH THE COLD FRONT CLOSER TO THE REGION THROUGHOUT TODAY AND TOMORROW. FOR TODAY... THE FT. HOOD VAD WIND PROFILER SHOWS 25 TO 30 KNOTS OF SOUTHERLY INFLOW FEEDING INTO THE THUNDERSTORM COMPLEX OVER NORTH TEXAS EARLY THIS MORNING. THIS SHOULD HELP THESE THUNDERSTORMS MAINTAIN THEMSELVES THROUGH THE REMAINDER OF THE EARLY MORNING HOURS. AS LOW LEVEL INFLOW VEERS AND WEAKENS LATER LATER THIS MORNING HOWEVER... UNCERTAINTY BEGINS TO INCREASE ON HOW FAR SOUTH THIS COMPLEX WILL MAKE IT. SOME HIGH RESOLUTION GUIDANCE SOLUTIONS /NOTABLY THE HRRR AND TEXAS TECH WRF/ SHOWS OUTFLOW FROM THIS COMPLEX REACHING THE BRAZOS VALLEY LATE MORNING/EARLY AFTERNOON. GIVEN RADAR AND SATELLITE TRENDS... THINK AREAS NORTH OF A BRENHAM TO LIVINGSTON LINE APPEAR TO BE THE MOST LIKELY TO SEE RAIN FROM THIS COMPLEX OR ANY ASSOCIATED OUTFLOW AND HIGHLIGHTING THE HIGHEST POPS FOR THE DAY IN THESE AREAS. EVEN IF THE STORMS DISSIPATE BEFORE THE OUTFLOW REACHES THE AREA... DIABATIC HEATING MAY CONTRIBUTE TO ADDITIONAL DEVELOPMENT ALONG IT LATER THIS AFTERNOON. FARTHER SOUTH... CONVECTIVE TEMPERATURES NEAR 90 TODAY WILL ALSO SUPPORT ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT ACROSS THE REMAINDER OF THE REGION... ESPECIALLY AS A SEA BREEZE MOVES FARTHER INLAND. THE UPPER LOW CHURNING OVER THE NORTHERN GULF EARLY THIS MORNING IS EXPECTED TO SHEAR OUT TODAY... DECREASING THE SUBSIDENCE THAT HAS LIMITED MORE ROBUST COVERAGE OVER THE PAST FEW DAYS. IF THE OUTFLOW IS ABLE TO MAKE IT FARTHER SOUTH TODAY THAN ORIGINALLY THOUGHT... POPS ALSO WILL NEED TO BE INCREASED FARTHER SOUTH TODAY. ADDITIONALLY... FORECAST SOUNDINGS FOR HOUSTON THIS AFTERNOON HAVE A DISTINCT INVERTED-V SIGNATURE AND THIS WILL SUPPORT AT LEAST AN ISOLATED GUSTY WIND THREAT FROM ANY THUNDERSTORM THAT DEVELOPS. THE COLD FRONT IS EXPECTED TO MAKE SLOW PROGRESS ACROSS NORTH TEXAS TODAY... AND WITH SOME UNCERTAINTY ON WHERE OUTFLOW FROM TODAY/S THUNDERSTORMS WILL END UP KEEPING POPS HIGHEST TONIGHT ALONG AND NORTH OF A BRENHAM TO CLEVELAND LINE. AS PRECIPITABLE WATER VALUES RISE TO NEAR 2 INCHES LATER TODAY AND INTO TOMORROW... LOCALLY HEAVY RAIN WILL REMAIN POSSIBLE. OTHERWISE... EXPECT HIGHS IN THE UPPER 80S TO LOW 90S TODAY AND LOWS IN THE 70S TO NEAR 80 TONIGHT. THE GREAT PLAINS UPPER TROUGH WILL CONTINUE TO SWING EAST TOWARDS THE GREAT LAKES ON THURSDAY... WITH ITS AXIS EXTENDING OVER THE REGION. THE COLD FRONT WILL MAKE MORE PROGRESS INTO/ STALL SOMEWHERE ACROSS CENTRAL TEXAS ON THURSDAY AND THIS WITH ADDED LIFT FROM A 50-60 KNOT UPPER LEVEL JET STREAK APPROACHING FROM WEST TEXAS WILL KEEP SCATTERED TO NUMEROUS THUNDERSTORMS IN THE FORECAST ON THURSDAY AND FRIDAY. HIGHS TO END THE WEEK WILL BE NEAR NORMAL IN THE MID TO UPPER 80S. HEADING INTO THE WEEKEND... A STRONG SHORTWAVE TROUGH ROTATING AROUND THE BASE OF THE BROAD UPPER TROUGH FRIDAY/SATURDAY WILL SEND A SECONDARY... STRONGER FRONT INTO THE REGION. THIS FRONT LOOKS TO PUSH THROUGH THE REGION SOMETIME ON SATURDAY WITH MUCH DRIER AIR FILTERING INTO THE AREA BEHIND IT. PRECIPITABLE WATER VALUES WILL FALL THROUGHOUT THE DAY ON SATURDAY... BOTTOMING OUT UNDER ONE INCH ON SUNDAY. THIS WILL ALLOW RAIN CHANCES TO TAPER OFF FROM NORTH TO SOUTH DURING THE DAY ON SATURDAY AND PROVIDE WHAT APPEARS TO BE A VERY PLEASANT SUNDAY IN THE MAKING. DRIER AIR WILL ALLOW FOR OVERNIGHT LOW TEMPERATURES TO POSSIBLY FALL INTO THE 60S SUNDAY... WITH HIGHS IN THE LOW TO MID 80S. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW THE DEVELOPMENT OF A COASTAL TROUGH/SURFACE LOW OFF MEXICO/DEEP SOUTH TEXAS HEADING INTO THE BEGINNING OF NEXT WEEK. WHILE STILL OFFERING SOMEWHAT DIFFERENT SOLUTIONS... THE GFS AND THE EUROPEAN BOTH ADVERTISE A GOOD SLUG OF TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE MAKING ITS WAY BACK INTO THE REGION /GFS PWATS INCREASE FROM LESS THAN ONE INCH MONDAY TO NEARLY 2 INCHES ON TUESDAY/ HEADING INTO THE MIDDLE OF NEXT WEEK. SHOWER AND THUNDERSTORM CHANCES WILL RETURN AS THIS SYSTEM EJECTS NORTHWARD TOWARDS THE TEXAS COAST... AND WILL NEED TO CONTINUE TO MONITOR FOR THE POTENTIAL OF HEAVY RAIN. HUFFMAN MARINE... LIGHT TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH FRIDAY. PERIODS OF UNSETTLED WEATHER CAN BE EXPECTED...ESPECIALLY THURSDAY THROUGH SATURDAY...AS UPPER LEVEL DISTURBANCES INTERACT WITH DEEPER MOISTURE IN THE AREA. WINDS/SEAS WILL BE HIGHER IN AND NEAR STORMS. A WEAK FRONTAL BOUNDARY WILL PUSH INTO THE WATERS LATE FRIDAY NIGHT OR SATURDAY MORNING WITH NORTHEAST WINDS IN ITS WAKE. A WEAK TROUGH OF LOW PRESSURE WILL DEVELOP NEAR THE LOWER TEXAS COAST EARLY NEXT WEEK AND THIS FEATURE WILL BRING PERIODS OF SHRA/TSRA AND A PROLONGED PERIOD OF E-SE WINDS TO THE UPPER TEXAS COASTAL WATERS. 43 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 91 75 89 74 89 / 40 50 60 30 40 HOUSTON (IAH) 91 75 89 74 87 / 40 30 60 40 50 GALVESTON (GLS) 88 81 89 79 85 / 40 30 60 50 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...39
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
652 AM CDT WED SEP 9 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS PREVAIL OVER DEEP SOUTH TEXAS THIS MORNING. VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS...EXCEPT A BRIEF PERIOD OF MVFR CONDITIONS POSSIBLE IN ANY CONVECTION. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. LIGHT SOUTHEAST WINDS WILL BECOME MODERATE LATER THIS MORNING WITH GUSTS AROUND 20 KNOTS IN THE AFTERNOON. WINDS WILL GRADUALLY WEAKEN THIS EVENING AND OVERNIGHT. && .PREV DISCUSSION... /ISSUED 434 AM CDT WED SEP 9 2015/ SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR SATELLITE IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN MEXICO AND A 500MB LOW OVER THE WESTERN GULF OF MEXICO. BROWNSVILLE RADAR SHOWS VERY ISOLATED ACTIVITY ACROSS THE LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS CONVECTION WILL INCREASE ACROSS THE GULF WATERS LATER THIS MORNING. BRO SOUNDING FROM TUESDAY EVENING INDICATES PRECIPITABLE WATER VALUES OF 2.02 INCHES. MOSTLY CLEAR SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS MORNING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS. THE COMBINATION OF THE 500MB LOW ACROSS THE WESTERN GULF OF MEXICO AND A FRONT MOVING SOUTH OVER CENTRAL TEXAS WILL ALLOW LOW TO MID LEVEL MOISTURE TO INCREASE ACROSS DEEP SOUTH TEXAS THROUGH THE FORECAST PERIOD. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. THE LATEST HRRR/GFS AND ECMWF SUGGEST AN ACTIVE SEA BREEZE TODAY WHILE THE MET REMAINS GENERALLY DRY. WILL LEAN TOWARDS THE WETTER MAV/ECMWF MOS POPS FOR TODAY. DEEPER MOISTURE SHOULD SUPPORT MORE ACTIVITY ACROSS THE AREA ON THURSDAY...ESPECIALLY ACROSS THE COASTAL WATERS AND THE RANCHLANDS. WILL BLEND TOWARDS THE WETTER NAM/ECMWF FOR POPS AREA WIDE FOR THURSDAY. ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY AND THURSDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY THOSE WITH A HISTORY OF FLOODING. HIGH TEMPERATURES TODAY WILL RANGE FROM THE LOWER 90S NEAR THE COAST TO AROUND 100 ACROSS THE UPPER VALLEY. HIGH TEMPERATURES WILL BE A FEW DEGREES LOWER ON THURSDAY DUE TO THE INCREASE IN CLOUDS AND RAIN CHANCES. LOW TEMPERATURES TONIGHT WILL GENERALLY BE IN THE UPPER 70S TO AROUND 80. LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...RATHER BUSY LONG TERM PORTION OF THE FORECAST ANTICIPATED. DEEP TROPICAL MOISTURE (PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES) WILL COMBINE WITH THE FRIDAY NIGHT PASSAGE OF A WEAK COLD FRONT...AND THE SUBSEQUENT DEVELOPMENT AND PERSISTENCE OF AN INVERTED SURFACE TROUGH OF LOW PRESSURE ALONG THE LOWER TEXAS COAST AFTERWARDS. WITH PERSISTENT 500 MB TROUGHINESS ALONG THE TEXAS COASTLINE IN ASSOCIATION WITH A CLOSED 500 MB LOW PRESSURE SYSTEM OVER THE GREAT LAKES REGION...DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY CAN EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FOR MUCH OF THE FORECAST PERIOD...WITH THE HIGHEST RAIN CHANCES FROM FRIDAY THROUGH SATURDAY...WHEN LOCALLY HEAVY RAINFALL HAS ALSO BEEN INCLUDED IN THE FORECAST. THE MOST INTERESTING ASPECT OF THE LONG TERM FORECAST PERIOD IS THE GFS` INDICATION THAT A WEAK CLOSED AREA OF LOW PRESSURE WILL FORM OVER THE WESTERN GULF OF MEXICO AND MOVE INLAND OVER THE BRO CWFA TOWARDS THE END OF THE FORECAST PERIOD. ANY CLOSED AREA OF LOW PRESSURE...SHOULD IT FORM...WOULD HAVE THE ABILITY TO RADICALLY CHANGE PRECIPITATION AND WIND VALUES ON MONDAY AND TUESDAY...AND THIS WILL NEED TO BE MONITORED BY SUCCESSIVE SHIFTS THROUGH THE NEXT FEW DAYS. MARINE...NOW THROUGH THURSDAY...BUOY DATA AND OBSERVATION PLATFORMS ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN 8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A WEAK PRESSURE GRADIENT OVER THE WESTERN GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND LOW TO MODERATE SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS. THURSDAY NIGHT THROUGH TUESDAY...GENERALLY LIGHT TO MODERATE WINDS AND LOW TO MODERATE SEAS ARE EXPECTED THROUGH THE PERIOD AS WEAK LOW PRESSURE PERSISTS OVER THE WESTERN GULF OF MEXICO AND A COLD FRONT INTRUDES INTO THE LOWER TEXAS COASTAL WATERS. WEAK CLOSED LOW PRESSURE MAY DEVELOP ALONG THE LOWER TEXAS COAST TOWARDS THE END OF THE FORECAST PERIOD PER ONE WEATHER FORECAST MODEL...BUT THE STRONGER WINDS AND HIGHER SEAS INDICATED IN ASSOCIATION WITH THE LOW PRESSURE DEVELOPMENT HAVE NOT BEEN INCLUDED IN THE FORECAST AT THIS TIME. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 63
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
624 AM CDT WED SEP 9 2015 .DISCUSSION... SEE 12Z AVIATION DISCUSSION. && .AVIATION... PRECIP OVER N TX CONTINUES TO SAG SOUTH AND IF THE LINE HOLDS TOGETHER...IT SHOULD ARRIVE AT NORTHERN TAF SITES AROUND 15Z. SHORT TERM GUIDANCE SUGGESTS THAT THE AREA WILL WEAKEN AND IR IMAGERY SHOWS SOME SLIGHT WARMING OF THE CLOUD TOPS. KGRK VWP STILL SHOWING 30 KTS OF INFLOW INTO THE LINE WHICH SHOULD HELP SUSTAIN THE LINE. PW VALUES WILL EXCEED 2.00 INCHES OVER MUCH OF THEN AREA TODAY SO SCT SHRA/ISO TSRA WILL BE POSSIBLE AT ALL TAF SITES TODAY. TIMING IS THE TRICKY PART. TOOK A BLEND OF THE NAM... GFS AND THE ECMWF WITH BEST RAIN CHANCES AT THE HOUSTON TERMINALS BETWEEN 18-03Z. NCEP 4 KM WRF IS VERY AGGRESSIVE WITH PRECIP BETWEEN 09-12Z THURSDAY OVER THE SOUTHERN TAF SITES. NOT SURE IF IT IS ON TO SOMETHING BUT ADDED VCSH FOR KSGR...KHOU...KLBX AND KGLS FOR EARLY THURSDAY MORNING. 43 && .PREV DISCUSSION... /ISSUED / DISCUSSION... REGIONAL RADAR MOSAIC EARLY THIS MORNING SHOWED A COMPLEX OF THUNDERSTORMS LOCATED ALONG THE INTERSTATE 20 CORRIDOR PUSHING SOUTH. EARLY MORNING WATER VAPOR IMAGERY SHOWED THIS COMPLEX WAS AIDED BY A SHORTWAVE TROUGH MOVING ACROSS NORTH TEXAS... WITH 06Z SURFACE ANALYSIS PLACING A COLD FRONT BEHIND THESE THUNDERSTORMS FROM WEST TEXAS INTO CENTRAL OKLAHOMA. EVENING UPPER AIR ANALYSIS SHOWED A BROAD UPPER TROUGH SWINGING ACROSS THE SOUTHERN/CENTRAL PLAINS AND THIS TROUGH WILL HELP PUSH THE COLD FRONT CLOSER TO THE REGION THROUGHOUT TODAY AND TOMORROW. FOR TODAY... THE FT. HOOD VAD WIND PROFILER SHOWS 25 TO 30 KNOTS OF SOUTHERLY INFLOW FEEDING INTO THE THUNDERSTORM COMPLEX OVER NORTH TEXAS EARLY THIS MORNING. THIS SHOULD HELP THESE THUNDERSTORMS MAINTAIN THEMSELVES THROUGH THE REMAINDER OF THE EARLY MORNING HOURS. AS LOW LEVEL INFLOW VEERS AND WEAKENS LATER LATER THIS MORNING HOWEVER... UNCERTAINTY BEGINS TO INCREASE ON HOW FAR SOUTH THIS COMPLEX WILL MAKE IT. SOME HIGH RESOLUTION GUIDANCE SOLUTIONS /NOTABLY THE HRRR AND TEXAS TECH WRF/ SHOWS OUTFLOW FROM THIS COMPLEX REACHING THE BRAZOS VALLEY LATE MORNING/EARLY AFTERNOON. GIVEN RADAR AND SATELLITE TRENDS... THINK AREAS NORTH OF A BRENHAM TO LIVINGSTON LINE APPEAR TO BE THE MOST LIKELY TO SEE RAIN FROM THIS COMPLEX OR ANY ASSOCIATED OUTFLOW AND HIGHLIGHTING THE HIGHEST POPS FOR THE DAY IN THESE AREAS. EVEN IF THE STORMS DISSIPATE BEFORE THE OUTFLOW REACHES THE AREA... DIABATIC HEATING MAY CONTRIBUTE TO ADDITIONAL DEVELOPMENT ALONG IT LATER THIS AFTERNOON. FARTHER SOUTH... CONVECTIVE TEMPERATURES NEAR 90 TODAY WILL ALSO SUPPORT ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT ACROSS THE REMAINDER OF THE REGION... ESPECIALLY AS A SEA BREEZE MOVES FARTHER INLAND. THE UPPER LOW CHURNING OVER THE NORTHERN GULF EARLY THIS MORNING IS EXPECTED TO SHEAR OUT TODAY... DECREASING THE SUBSIDENCE THAT HAS LIMITED MORE ROBUST COVERAGE OVER THE PAST FEW DAYS. IF THE OUTFLOW IS ABLE TO MAKE IT FARTHER SOUTH TODAY THAN ORIGINALLY THOUGHT... POPS ALSO WILL NEED TO BE INCREASED FARTHER SOUTH TODAY. ADDITIONALLY... FORECAST SOUNDINGS FOR HOUSTON THIS AFTERNOON HAVE A DISTINCT INVERTED-V SIGNATURE AND THIS WILL SUPPORT AT LEAST AN ISOLATED GUSTY WIND THREAT FROM ANY THUNDERSTORM THAT DEVELOPS. THE COLD FRONT IS EXPECTED TO MAKE SLOW PROGRESS ACROSS NORTH TEXAS TODAY... AND WITH SOME UNCERTAINTY ON WHERE OUTFLOW FROM TODAY/S THUNDERSTORMS WILL END UP KEEPING POPS HIGHEST TONIGHT ALONG AND NORTH OF A BRENHAM TO CLEVELAND LINE. AS PRECIPITABLE WATER VALUES RISE TO NEAR 2 INCHES LATER TODAY AND INTO TOMORROW... LOCALLY HEAVY RAIN WILL REMAIN POSSIBLE. OTHERWISE... EXPECT HIGHS IN THE UPPER 80S TO LOW 90S TODAY AND LOWS IN THE 70S TO NEAR 80 TONIGHT. THE GREAT PLAINS UPPER TROUGH WILL CONTINUE TO SWING EAST TOWARDS THE GREAT LAKES ON THURSDAY... WITH ITS AXIS EXTENDING OVER THE REGION. THE COLD FRONT WILL MAKE MORE PROGRESS INTO/ STALL SOMEWHERE ACROSS CENTRAL TEXAS ON THURSDAY AND THIS WITH ADDED LIFT FROM A 50-60 KNOT UPPER LEVEL JET STREAK APPROACHING FROM WEST TEXAS WILL KEEP SCATTERED TO NUMEROUS THUNDERSTORMS IN THE FORECAST ON THURSDAY AND FRIDAY. HIGHS TO END THE WEEK WILL BE NEAR NORMAL IN THE MID TO UPPER 80S. HEADING INTO THE WEEKEND... A STRONG SHORTWAVE TROUGH ROTATING AROUND THE BASE OF THE BROAD UPPER TROUGH FRIDAY/SATURDAY WILL SEND A SECONDARY... STRONGER FRONT INTO THE REGION. THIS FRONT LOOKS TO PUSH THROUGH THE REGION SOMETIME ON SATURDAY WITH MUCH DRIER AIR FILTERING INTO THE AREA BEHIND IT. PRECIPITABLE WATER VALUES WILL FALL THROUGHOUT THE DAY ON SATURDAY... BOTTOMING OUT UNDER ONE INCH ON SUNDAY. THIS WILL ALLOW RAIN CHANCES TO TAPER OFF FROM NORTH TO SOUTH DURING THE DAY ON SATURDAY AND PROVIDE WHAT APPEARS TO BE A VERY PLEASANT SUNDAY IN THE MAKING. DRIER AIR WILL ALLOW FOR OVERNIGHT LOW TEMPERATURES TO POSSIBLY FALL INTO THE 60S SUNDAY... WITH HIGHS IN THE LOW TO MID 80S. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW THE DEVELOPMENT OF A COASTAL TROUGH/SURFACE LOW OFF MEXICO/DEEP SOUTH TEXAS HEADING INTO THE BEGINNING OF NEXT WEEK. WHILE STILL OFFERING SOMEWHAT DIFFERENT SOLUTIONS... THE GFS AND THE EUROPEAN BOTH ADVERTISE A GOOD SLUG OF TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE MAKING ITS WAY BACK INTO THE REGION /GFS PWATS INCREASE FROM LESS THAN ONE INCH MONDAY TO NEARLY 2 INCHES ON TUESDAY/ HEADING INTO THE MIDDLE OF NEXT WEEK. SHOWER AND THUNDERSTORM CHANCES WILL RETURN AS THIS SYSTEM EJECTS NORTHWARD TOWARDS THE TEXAS COAST... AND WILL NEED TO CONTINUE TO MONITOR FOR THE POTENTIAL OF HEAVY RAIN. HUFFMAN MARINE... LIGHT TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH FRIDAY. PERIODS OF UNSETTLED WEATHER CAN BE EXPECTED...ESPECIALLY THURSDAY THROUGH SATURDAY...AS UPPER LEVEL DISTURBANCES INTERACT WITH DEEPER MOISTURE IN THE AREA. WINDS/SEAS WILL BE HIGHER IN AND NEAR STORMS. A WEAK FRONTAL BOUNDARY WILL PUSH INTO THE WATERS LATE FRIDAY NIGHT OR SATURDAY MORNING WITH NORTHEAST WINDS IN ITS WAKE. A WEAK TROUGH OF LOW PRESSURE WILL DEVELOP NEAR THE LOWER TEXAS COAST EARLY NEXT WEEK AND THIS FEATURE WILL BRING PERIODS OF SHRA/TSRA AND A PROLONGED PERIOD OF E-SE WINDS TO THE UPPER TEXAS COASTAL WATERS. 43 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 92 75 89 74 89 / 60 50 60 30 40 HOUSTON (IAH) 91 75 89 74 87 / 40 30 60 40 50 GALVESTON (GLS) 90 81 89 79 85 / 30 30 60 50 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...14 AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
154 PM PDT WED SEP 9 2015 .SYNOPSIS... UPPER-LEVEL HIGH PRESSURE WILL CONTINUE HOT WEATHER THROUGH THURSDAY...WITH SLOW COOLING FRIDAY INTO EARLY NEXT WEEK. AFTERNOON AND EARLY EVENING HEAVY THUNDERSTORMS WILL CONTINUE OVER THE INLAND AREAS THROUGH THURSDAY...LEADING TO AN ENHANCED FLASH FLOOD THREAT...AS MOISTURE FROM HURRICANE LINDA MOVES OVER THE REGION. THE AFTERNOON AND EARLY EVENING THUNDERSTORM THREAT CONTINUES FOR THE MOUNTAINS AND DESERTS THROUGH THE WEEKEND. EVEN COASTAL AREAS MAY SEE A THUNDERSTORM OR TWO THIS AFTERNOON AND THURSDAY. COOLER AND DRIER NEXT WEEK AS A TROUGH OF LOW PRESSURE MOVES IN ALONG THE WEST COAST. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... MORNING SOUNDING CONTINUES TO SHOW A MOIST AND UNSTABLE ATMOSPHERE...WITH 1.65 INCHES OF PRECIPITABLE WATER AND 780 J/KG OF MOST UNSTABLE CAPE. CURRENT SPC MESOANALYSIS SHOWS 1000-1500 J/KG OF SURFACE BASED CAPE. THUS...RADAR SHOWS THAT THUNDERSTORMS ARE ERUPTING OVER THE MOUNTAINS...HIGH DESERTS AND VALLEYS THIS AFTERNOON. THE SOUNDING ALSO SHOWS MORE OF AN EASTERLY COMPONENT TO THE WINDS IN THE LOW LEVELS. WITH THE WRF SHOWING 700-500 MB WINDS OUT OF THE EAST OF AROUND 10-15 KT AND THE SURFACE CONVERGENCE BOUNDARY SETTING UP IN THE VALLEYS...THIS IS RESULTING IN THUNDERSTORMS DRIFTING IN THE VALLEY AREAS TODAY. IN FACT...THE LATEST HRRR SHOWS THAT THE SOME SHOWERS OR THUNDERSTORMS COULD DRIFT INTO THE COASTAL AREAS THIS AFTERNOON...SO HAVE ADDED A SLIGHT CHANCE OF THUNDERSTORMS/SHOWERS FOR THOSE AREAS WITH THE AFTERNOON FORECAST. ON THURSDAY...PRECIPITABLE WATER INCREASES TO 2 INCHES ACCORDING TO THE GFS AND NAM...AS THE CIRCULATION OF LINDA MOVES NORTHWEST TO A POSITION FAR WEST OF NORTHERN BAJA...RESULTING IN CONTINUED EAST TO SOUTHEAST FLOW BRINGING THE MOISTURE INTO THE AREA. WRF SHOWS THE EAST WINDS IN THE 700-500 MB LAYER INCREASING TO 20 KT...WHICH MEANS THAT STORMS SHOULD BE MOVING QUICKER AND THAT THEY MAY BE ABLE TO DRIFT INTO COASTAL AREAS AS WELL. ONE POSSIBLE LIMITING FACTOR ON THURSDAY IS IF THERE IS TOO MUCH CLOUD COVER...WHICH COULD DECREASE THE AMOUNT OF INSTABILITY. THERE IS STILL A FAIR AMOUNT OF MOISTURE IN THE REGION ON FRIDAY...WITH PRECIPITABLE WATER ONLY DECREASING TO 1.7-1.8 INCHES UNDER SOUTHEAST FLOW ALOFT...SO THUNDERSTORMS ARE LIKELY TO DEVELOP AGAIN FRIDAY AFTERNOON AND EARLY EVENING IN THE MOUNTAINS AND VALLEYS. THE AFTERNOON AND EARLY EVENING THUNDERSTORM THREAT CONTINUES FOR THE MOUNTAINS AND DESERTS SATURDAY WITH MOISTURE DIMINISHING A LITTLE...AND THEN THE GFS SHOWS MOISTURE DECREASING FURTHER ON SUNDAY. FOR DETAILS ON THE FLASH FLOOD THREAT...PLEASE SEE THE HYDROLOGY SECTION BELOW. THE HEAT AND MUGGY CONDITIONS IS THE OTHER STORY...AS OVERNIGHT LOWS WERE ONLY IN THE LOW TO MID 70S. THE LOW OF 77 DEGREES AT LINDBERGH FIELD WAS ONE DEGREE BELOW THE ALL-TIME HIGHEST MINIMUM TEMPERATURE. CURRENTLY...THE TEMPERATURES ARE SEVERAL DEGREES ARE HIGHER THAN AT THIS TIME YESTERDAY. SOME EASTERLY DOWNSLOPE FLOW ASSOCIATED WITH THE CIRCULATION OF LINDA COULD BRING CONTINUED HOT CONDITIONS TO THE SAN DIEGO COUNTY COAST AND VALLEYS THURSDAY AS WELL...ALTHOUGH IT DOES NOT LOOK QUITE AS HOT AS THE MODELS WERE SHOWING YESTERDAY. A SLOW COOLING TREND LOOKS TO START FRIDAY INTO SATURDAY...WITH MORE SIGNIFICANT COOLING SUNDAY INTO EARLY NEXT WEEK AS THE RIDGE WEAKENS AND WE GET A TROUGH ALONG THE WEST COAST. NIGHT AND MORNING MARINE LAYER CLOUDS COULD RETURN BY SATURDAY NIGHT. && .AVIATION... 092000Z...GENERALLY...NO VIS RESTRICTIONS INTO THURSDAY WITH OCCASIONAL CLOUDS ABOVE 10000 FEET MSL. BETWEEN 09/20-10/02Z THIS AFTERNOON...THUNDERSTORMS ARE POSSIBLE IN THE MOUNTAINS...DESERTS AND VALLEYS WITH BASES 8000 FEET MSL AND TOPS TO 45000 FEET. EXPECT STRONG UPDRAFTS AND DOWNDRAFTS...MAINLY SMALL HAIL...AND SURFACE GUSTS OVER 35 KT NEAR ANY STORM. IN STORMS LOCAL VIS REDUCED TO 2SM IN HEAVY RAIN AND/OR BLOWING DUST IN DESERTS. CONFIDENCE IN THE FORECAST OF A VERY LOW RISK OF LOW CLOUDS FOR KSAN TONIGHT IS HIGH...WITH EVEN LESS RISK OF LOW CLOUDS AT KONT OVERNIGHT TONIGHT. && .MARINE... 1255 PM...THERE IS A SLIGHT CHANCE OF A THUNDERSTORM THURSDAY AFTERNOON AND EVENING NEAR THE COAST. OTHERWISE...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SUNDAY. && .BEACHES... 1255 PM...A NEW SOUTH SOUTHEAST SWELL FROM HURRICANE LINDA WILL ARRIVE THIS AFTERNOON INTO FRIDAY MORNING. THIS SWELL WILL PRODUCE 4- 6 FOOT SURF AT ORANGE COUNTY BEACHES INTO FRIDAY...WITH A FEW HIGHER SETS. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS AT THE BEACHES THURSDAY AFTERNOON AND EVENING. THERE IS A BEACH HAZARDS STATEMENT IN EFFECT FOR ELEVATED SURF AND STRONG RIP CURRENTS THROUGH FRIDAY MORNING. && .HYDROLOGY... MODERATE TO HIGH FLASH FLOOD THREAT CONTINUES TODAY FOR THE MOUNTAINS...DESERTS AND THE VALLEYS...DUE TO THE MOIST AND UNSTABLE ATMOSPHERE. THUS...THUNDERSTORMS ARE ERUPTING OVER THE INLAND EMPIRE...HIGH DESERTS AND SAN BERNARDINO COUNT MOUNTAINS. THE WINDS ALOFT ARE SOMEWHAT WEAK AS WELL...RESULTING IN SOME SLOW MOVING STORMS WHICH ARE INCREASING THE THREAT OF FLASH FLOODING FURTHER. RAIN RATES OF 1 TO 2 INCHES PER HOUR WILL BE POSSIBLE UNDERNEATH THE HEAVIER STORMS. FLASH FLOODING HAS ALREADY OCCURRED IN FOREST FALLS THIS AFTERNOON. THE FLASH FLOOD WATCH CONTINUES THROUGH THURSDAY FOR THE MOUNTAINS...DESERTS AND VALLEYS...ALTHOUGH STORMS MAY BE MOVING QUICKER ON THURSDAY WHICH COULD DIMINISH THE FLASH FLOOD THREAT A BIT. HOWEVER...TRAINING STORMS COULD BE A CONCERN. THE THREAT LOWERS FURTHER FRIDAY INTO THE WEEKEND AS MOISTURE SLOWLY DECREASES. && .SKYWARN... SKYWARN ACTIVATION IS REQUESTED THROUGH EARLY EVENING FOR SAN DIEGO COUNTY...RIVERSIDE COUNTY...AND SAN BERNARDINO COUNTY. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR APPLE AND LUCERNE VALLEYS-COACHELLA VALLEY-RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY DESERTS- SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SAN GORGONIO PASS NEAR BANNING. HEAT ADVISORY UNTIL 6 PM PDT THURSDAY FOR ORANGE COUNTY INLAND AREAS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY COASTAL AREAS-SAN DIEGO COUNTY VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS. BEACH HAZARDS STATEMENT THROUGH FRIDAY MORNING FOR ORANGE COUNTY COASTAL AREAS. PZ...NONE. && $$ PUBLIC/HYDROLOGY...HARRISON AVIATION/MARINE/BEACHES...SMALL
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
958 AM PDT WED SEP 9 2015 .SYNOPSIS... UPPER-LEVEL HIGH PRESSURE WILL CONTINUE HOT WEATHER THROUGH THURSDAY...WITH SLOW COOLING FRIDAY INTO EARLY NEXT WEEK. AFTERNOON AND EARLY EVENING HEAVY THUNDERSTORMS WILL CONTINUE OVER THE INLAND AREAS THROUGH THURSDAY...LEADING TO AN ENHANCED FLASH FLOOD THREAT...AS MOISTURE FROM HURRICANE LINDA MOVES OVER THE REGION. THE AFTERNOON AND EARLY EVENING THUNDERSTORM THREAT CONTINUES FOR THE MOUNTAINS AND DESERTS THROUGH THE WEEKEND. EVEN COASTAL AREAS MAY SEE A THUNDERSTORM OR TWO THURSDAY. COOLER AND DRIER NEXT WEEK AS A TROUGH OF LOW PRESSURE MOVES IN ALONG THE WEST COAST. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... MORNING SOUNDING CONTINUES TO SHOW A MOIST AND UNSTABLE ATMOSPHERE...WITH 1.65 INCHES OF PRECIPITABLE WATER AND 780 J/KG OF MOST UNSTABLE CAPE. THE SOUNDING ALSO SHOWS MORE OF AN EASTERLY COMPONENT TO THE WINDS IN THE LOW LEVELS. VISIBLE SATELLITE SHOWS CIRRUS BLOW-OVER FROM LINDA MOVING IN FROM THE SOUTH...OBSCURING PARTS OF SAN DIEGO COUNTY AND THE COACHELLA VALLEY. ALTHOUGH THESE CLOUDS COULD HELP REDUCE TEMPERATURES A TINY BIT FOR THOSE AREAS...THERE IS STILL EXPECTED TO BE ENOUGH SUNSHINE TO CREATE ENOUGH INSTABILITY FOR THUNDERSTORMS TO ERUPT AGAIN THIS AFTERNOON AND EARLY EVENING. THE WRF SHOWS THE SURFACE CONVERGENCE BOUNDARY SETTING UP FARTHER WEST TODAY...OVER THE COASTAL FOOTHILLS...SO THAT COULD BE WHERE THUNDERSTORMS INITIATE. THE HRRR AND OTHER HI-RES MODELS FOCUS MUCH OF THE THUNDERSTORM ACTIVITY FOR THE RIVERSIDE AND SAN BERNARDINO COUNTY AREAS...INCLUDING THE MOUNTAINS...THE INLAND EMPIRE AND THE HIGH DESERTS...SO POPS HAVE BEEN ADJUSTED UPWARDS IN THOSE LOCATIONS. WITH THE WRF SHOWING 700-500 MB WINDS OUT OF THE EAST OF AROUND 10-15 KT...THIS SHOULD ALSO HELP WITH THUNDERSTORMS DRIFTING IN THE VALLEY AREAS TODAY. ON THURSDAY...PRECIPITABLE WATER INCREASES TO 2 INCHES ACCORDING TO THE GFS AND NAM...AS THE CIRCULATION OF LINDA MOVES NORTHWEST TO A POSITION FAR WEST OF NORTHERN BAJA...RESULTING IN CONTINUED EAST TO SOUTHEAST FLOW BRINGING THE MOISTURE INTO THE AREA. WRF SHOWS THE EAST WINDS IN THE 700-500 MB LAYER INCREASING TO 20 KT...WHICH MEANS THAT STORMS SHOULD BE MOVING QUICKER AND THAT THEY MAY BE ABLE TO DRIFT INTO COASTAL AREAS AS WELL. ONE POSSIBLE LIMITING FACTOR ON THURSDAY IS IF THERE IS TOO MUCH CLOUD COVER...WHICH COULD DECREASE THE AMOUNT OF INSTABILITY. THERE IS STILL A FAIR AMOUNT OF MOISTURE IN THE REGION ON FRIDAY...WITH PRECIPITABLE WATER ONLY DECREASING TO 1.7-1.8 INCHES UNDER SOUTHEAST FLOW ALOFT...SO THUNDERSTORMS ARE LIKELY TO DEVELOP AGAIN FRIDAY AFTERNOON AND EARLY EVENING IN THE MOUNTAINS AND VALLEYS. THE AFTERNOON AND EARLY EVENING THUNDERSTORM THREAT CONTINUES FOR THE MOUNTAINS AND DESERTS SATURDAY WITH MOISTURE DIMINISHING A LITTLE...AND THEN THE GFS SHOWS MOISTURE DECREASING FURTHER ON SUNDAY. FOR DETAILS ON THE FLASH FLOOD THREAT...PLEASE SEE THE HYDROLOGY SECTION BELOW. THE HEAT AND MUGGY CONDITIONS IS THE OTHER STORY...AS OVERNIGHT LOWS WERE ONLY IN THE LOW TO MID 70S. THE LOW OF 77 DEGREES AT LINDBERGH FIELD WAS ONE DEGREE BELOW THE ALL-TIME HIGHEST MINIMUM TEMPERATURE. WITH THE RIDGE ALOFT CONTINUING TO BUILD OVER THE REGION...TODAY WILL LIKELY BE THE HOTTEST DAY FOR MOST AREAS...WITH DAY-TIME HIGHS REACHING 10 TO 15 DEGREES ABOVE NORMAL...ALTHOUGH THE DESERTS WILL PROBABLY BE A LITTLE COOLER DUE TO INCREASED MOISTURE AND LOWERING 850 MB TEMPERATURES. SOME EASTERLY DOWNSLOPE FLOW ASSOCIATED WITH THE CIRCULATION OF LINDA COULD BRING CONTINUED HOT CONDITIONS TO THE SAN DIEGO COUNTY COAST AND VALLEYS THURSDAY AS WELL. A SLOW COOLING TREND LOOKS TO START FRIDAY INTO SATURDAY...WITH MORE SIGNIFICANT COOLING SUNDAY INTO EARLY NEXT WEEK AS THE RIDGE WEAKENS AND WE GET A TROUGH ALONG THE WEST COAST. NIGHT AND MORNING MARINE LAYER CLOUDS COULD RETURN BY SATURDAY NIGHT. && .AVIATION... 091600Z...GENERALLY...NO VIS RESTRICTIONS TODAY AND TONIGHT WITH OCCASIONAL CLOUDS ABOVE 10000 FEET MSL. BETWEEN 19-01Z TODAY...THUNDERSTORMS ARE POSSIBLE IN THE MOUNTAINS...DESERTS AND VALLEYS WITH BASES 8000 FEET MSL AND TOPS TO 45000 FEET. EXPECT STRONG UPDRAFTS AND DOWNDRAFTS...SMALL HAIL...AND SURFACE GUSTS OVER 35 KT NEAR ANY STORM. IN STORMS LOCAL VIS REDUCED TO 2SM IN HEAVY RAIN AND/OR BLOWING DUST IN DESERTS. CONFIDENCE IN THE FORECAST OF A VERY LOW RISK OF LOW CLOUDS FOR KSAN TONIGHT IS HIGH...WITH EVEN LESS RISK OF LOW CLOUDS AT KONT OVERNIGHT TONIGHT. && .MARINE... 800 AM...THERE IS A SLIGHT CHANCE OF A THUNDERSTORM THURSDAY AFTERNOON AND EVENING NEAR THE COAST. OTHERWISE...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SUNDAY. && .BEACHES... 800 AM...A NEW SOUTH SOUTHEAST SWELL FROM HURRICANE LINDA WILL ARRIVE THURSDAY. THIS SWELL WILL PRODUCE 5-7 FOOT SURF AT ORANGE COUNTY BEACHES THURSDAY INTO FRIDAY WITH A FEW HIGHER SETS. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS AT THE BEACHES THURSDAY AFTERNOON AND EVENING. && .HYDROLOGY... WITH THUNDERSTORMS EXPECTED TO DEVELOP IN THE INLAND VALLEYS OF SAN DIEGO COUNTY TODAY...THIS AREA HAS BEEN ADDED TO THE FLASH FLOOD WATCH. MODERATE TO HIGH FLASH FLOOD THREAT CONTINUES TODAY FOR THE MOUNTAINS...DESERTS AND THE VALLEYS...AS THE ATMOSPHERE WILL REMAIN MOIST AND UNSTABLE THROUGH THAT TIME. THIS WILL CREATE THE CHANCES FOR THUNDERSTORMS PRODUCING HEAVY RAIN. THE WINDS ALOFT WILL BE SOMEWHAT WEAK AS WELL...RESULTING IN SOME SLOW MOVING STORMS WHICH WILL INCREASE THE THREAT OF FLASH FLOODING FURTHER. RAIN RATES OF 1 TO 2 INCHES PER HOUR WILL BE POSSIBLE UNDERNEATH THE HEAVIER STORMS. THE FLASH FLOOD WATCH CONTINUES THROUGH THURSDAY FOR THESE AREAS...ALTHOUGH STORMS MAY BE MOVING QUICKER ON THURSDAY WHICH COULD DIMINISH THE FLASH FLOOD THREAT A BIT. THE THREAT LOWERS FURTHER FRIDAY INTO THE WEEKEND AS MOISTURE SLOWLY DECREASES. && .SKYWARN... SKYWARN ACTIVATION IS REQUESTED FOR NOON TODAY THROUGH EARLY EVENING FOR SAN BERNARDINO...RIVERSIDE AND SAN DIEGO COUNTIES. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR APPLE AND LUCERNE VALLEYS-COACHELLA VALLEY-RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY DESERTS- SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SAN GORGONIO PASS NEAR BANNING. HEAT ADVISORY UNTIL 6 PM PDT THURSDAY FOR ORANGE COUNTY INLAND AREAS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY COASTAL AREAS-SAN DIEGO COUNTY VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS. PZ...NONE. && $$ PUBLIC/HYDROLOGY...HARRISON AVIATION/MARINE/BEACHES...SMALL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
215 PM MDT WED SEP 9 2015 .SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT) ISSUED AT 215 PM MDT WED SEP 9 2015 DRY WEST NORTHWEST FLOW PREVAILS AND KEEPS MOISTURE SOUTH OF OUR SOUTHERN BORDER. THERE IS REMOTE CHANCE THAT A BRIEF SHOWER/STORM FORMS OVER THE ERN SAN JUAN MOUNTAINS. WATER VAPOR SHOWS PRONOUNCED DRY LAYER ACROSS THE SOUTH...AND COULD BE ONE REASON WHY THE HRRR MODEL SHOWS NO SHOWERS/STORMS ACROSS THE SRN MOUNTAINS AND FOOTHILLS. STABLE CONDITIONS CONTINUE THURSDAY KEEPING CONDITIONS DRY AND WINDS UPSLOPE/DOWNSLOPE INDUCED. VERTICAL PROFILES INDICATE WINDS BELOW 600 MB WILL BE VERY LIGHT - LESS THAN 15 KTS AND NEAR NON- EXISTENT AT THE SURFACE ON THURSDAY...WITH THE EXCEPTION OF THE SOUTHWEST COLORADO VALLEYS WHERE WINDS ALOFT AT 300 MB ARE STILL 40 KTS THROUGH THURSDAY EVENING SO SOME HIGHER GUSTS (TO 20 MPH OR SO) MAY MIX DOWN TO THE SURFACE. TEMPERATURES WILL REMAIN ABOVE NORMAL. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 215 PM MDT WED SEP 9 2015 VERY LITTLE CHANGE IN THE MID RANGE FORECAST PERIOD AS HIGH PRESSURE PERSISTS. ALONG THE WEST COAST...A TROUGH DEVELOPS ON SATURDAY AND WHAT HAPPENS WITH THIS SYSTEM IS OUR NEXT FORECAST CHALLENGE. THE 12Z GFS INDICATES A SMALL CLOSED LOW DEVELOPING IN SOUTHERN UTAH AND PROPAGATING INTO WESTERN COLORADO ON MONDAY WHILE THE EC BRINGS AN OPEN WAVE TROUGH INTO THE FOUR CORNERS. BOTH SOLUTIONS BRING PRECIPITATION TO THE REGION...SO CONFIDENCE IS GOOD ON AN INCREASE IN MOISTURE AND THE POSSIBILITY OF RAIN EARLY NEXT WEEK. TUESDAY LOOKS QUITE BREEZY AND WET WITH EITHER MODEL SOLUTION AS A COLD 700 MB LOW PRESSURE SYSTEM BARRELS DOWN INTO THE NORTHERN ROCKIES ON TUESDAY INTERACTING WITH THE MUCH WARMER AIR IN PLACE TO THE SOUTH. THERE HAVE BEEN PRETTY MAJOR FLUCTUATIONS RUN TO RUN IN THE FORECAST MODELS FOR EARLY NEXT WEEK AS THE PATTERN TRANSITIONS...SO DETAILS WILL HAVE TO BE IRONED OUT AS A SOLUTION BECOMES MORE CONSISTENT. THE GENERAL PATTERN DOES LOOK WETTER AND COOLER NEXT WEEK WITH AN AUTUMN-LIKE LOOK TO THE PATTERN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1126 AM MDT WED SEP 9 2015 NO SIGNIFICANT WEATHER OR AVIATION HAZARDS ARE EXPECTED THROUGH THE TIME PERIOD. VFR AND MOSTLY P6SM SKC WITH LIGHT DIURNAL WIND CIRCULATIONS. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...PF/JAM LONG TERM...JAM AVIATION...PF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
335 PM EDT WED SEP 9 2015 .SYNOPSIS... A COLD FRONT WILL SLOWLY MOVE INTO THE REGION TONIGHT BEFORE STALLING NEAR THE SOUTH COAST THURSDAY. LOW PRESSURE WILL TRACK SOUTH OF NEW ENGLAND THURSDAY INTO FRIDAY BRINGING WIDESPREAD SHOWERS AND SOME THUNDERSTORMS...ALONG WITH HEAVY RAINFALL AT TIMES. AS AN AREA OF LOW PRESSURE DEPARTS ON FRIDAY...A LULL IN THE WEATHER WILL FOLLOW PRIOR TO AN ANOMALOUS WEATHER SYSTEM FOR THE WEEKEND WHICH WILL LIKELY BRING THE AREA SOME RAIN FOR SUNDAY. AS THE SYSTEM EXITS...MILDER WEATHER WILL FOLLOW WITH ABOVE- AVERAGE TEMPERATURES BENEATH HIGH PRESSURE INTO NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... RECORD MAX TEMP HAS BEEN SET AT BOS AND BDL. SO FAR PVD IS ONE DEGREE SHY OF THE RECORD. RADAR SHOWS WIDELY SCT SHOWERS AND PERHAPS AN EMBEDDED TSTM MOVING INTO W MA. MLCAPES CLOSE TO 1000 J/KG WITH EFFECTIVE SHEAR 30 KT SO CANT RULE OUT AN ISOLD STRONG STORM BUT HRRR WEAKENS THE CONVECTION AS IT MOVES EAST INTO A LESS FAVORABLE ENVIRONMENT. MORE WIDESPREAD CONVECTION AHEAD OF THE COLD FRONT WAS MOVING EAST FROM CENTRAL AND NORTHERN NY. THIS AREA WAS ASSOCD WITH DECENT LOW LEVEL FRONTOGENESIS AND MLCAPES UP TO 1000 J/KG. MODELS BRING THIS FRONTOGENESIS INTO THE REGION THIS EVENING BUT INSTABILITY IS FORECAST TO WEAKEN TOWARD 00Z SO WE EXPECT WEAKENING LINE OF CONVECTION MOVING INTO THE THE REGION FROM THE WEST AROUND OR AFT 00Z PER HIRES ARW/NMM. COLD FRONT MOVES SLOWLY EAST ACROSS SNE TONIGHT REACHING THE COASTAL PLAIN TOWARD 00Z. WE WILL LIKELY SEE A LULL IN ACTIVITY OVERNIGHT ALTHOUGH CANT RULE OUT A FEW SHOWERS OR AN ISOLD TSTM...ESPECIALLY COASTAL PLAIN LATER TONIGHT WITHIN THE LOW LEVEL THETA-E RIDGE AHEAD OF THE COLD FRONT. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... *** LOCALLY HEAVY RAINFALL LIKELY THURSDAY INTO THURSDAY NIGHT *** INSTABILITY AXIS DEVELOPS ACROSS THE COASTAL PLAIN IN THE MORNING WITHIN THE THETA-E RIDGE AND WILL LIKELY SEE A GENERATION OF SHOWERS AND TSTMS ACROSS E CT...RI AND SE MA THU MORNING ALONG THE FRONTAL BOUNDARY. GIVEN PWATS INCREASING OVER 2 INCHES...LOCALLY HEAVY RAINFALL IS POSSIBLE. THE FRONT IS EXPECTED TO STALL NEAR THE SOUTH COAST AS LOW PRES DEVELOPS OVER THE MID ATLC COAST...THEN LIFTING NE AND TRACKING SOUTH OF NEW ENGLAND THU NIGHT. CLASSIC COLD SEASON SCENARIO WITH LOW LEVEL FRONTOGENESIS AND CONVERGENCE DEVELOPING ON THE NW PERIPHERY OF SFC LOW AND MID LEVEL CENTER WITHIN RIGHT ENTRANCE REGION OF THE UPPER JET. THE BEST LOW LEVEL FORCING BECOMES ALIGNED ACROSS W NEW ENG SO WE EXPECT FOCUS FOR HEAVIER RAINFALL TO SHIFT TO THE WEST ACROSS W MA AND N CT DURING THU AFTERNOON INTO THU NIGHT...EVENTUALLY REACHING THE COAST LATE THU NIGHT INTO EARLY FRI. SFC INSTABILITY IS LIMITED IN THE WEST ON THE COOL SIDE OF THE BOUNDARY BUT THERE IS ENOUGH ELEVATED INSTABILITY FOR A FEW TSTMS. ANOMALOUS PWATS SUGGEST LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREAT WITH AREAS OF URBAN AND POOR DRAINAGE FLOODING POSSIBLE. RAINFALL AMOUNTS OF 1 TO 2 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE WITH AXIS OF HEAVIEST RAINFALL LIKELY ACROSS WESTERN NEW ENGLAND. LESSER RAINFALL AMOUNTS EXPECTED IN SE NEW ENG. MUCH COOLER THU WITH MAX TEMPS MOSTLY IN THE 70S...BUT MAY REACH 80 ACROSS PORTIONS OF RI AND E MA. STILL QUITE HUMID IN E NEW ENG WITH DEWPOINTS NEAR 70. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... HIGHLIGHTS... * SHOWERS DISSIPATING THROUGH THE DAY FRIDAY * A LULL IN THE WEATHER AROUND SATURDAY * RETURN OF WET-WEATHER AND POSSIBLE THUNDERSTORMS FOR SUNDAY * LOOKING DRY WITH ABOVE- AVERAGE TEMPERATURES INTO NEXT WEEK DISCUSSION... AN ANOMALOUS WEEKEND SETUP INTO EARLY NEXT WEEK THAT WARRANTS AN ENSEMBLE FORECAST APPROACH. GOOD AGREEMENT ON A DEEP TROUGH PATTERN EVOLVING INTO A QUASI CUT-OFF CLOSED LOW OVER THE OHIO RIVER VALLEY REGION OVER THE WEEKEND...DEAMPLIFYING AS AN OPEN-WAVE OVER THE NE EARLY NEXT WEEK. THEREAFTER ENSEMBLE MEANS CONTINUE TO ADVERTISE RIDGING ACROSS THE REGION WITH PREFERRED TROUGHING TO THE W AND A MAINTAINED AREA OF LOW PRESSURE OVER THE N ATLANTIC. APPEARANCES WOULD LEAD TO BELIEVE THAT SUMMER IS NOT OVER QUITE YET AS THE 8-14 DAY FORECASTS FROM THE CLIMATE PREDICTION CENTER HAVE INCREASED ABOVE-AVERAGE TEMPERATURE PROBABILITY. NORMALS FOR MID-SEPTEMBER ARE AROUND THE LOW- TO MID-70S FOR HIGHS WITH LOW- TO MID-50S FOR LOWS. FRIDAY INTO SATURDAY... SOME INITIAL SHOWERS AND CLOUDY CONDITIONS TO START ON FRIDAY SHOULD BREAK W TO E AS DRIER AIR MOVES IN AND SUBSIDENCE PROCEEDS BENEATH RIDGING AHEAD OF THE CLOSED-LOW OVER THE OHIO RIVER VALLEY EXPECT A LULL IN THE WEATHER-ACTIVITY FRIDAY INTO SATURDAY...THOUGH UNCERTAIN AS TO WHEN IT WILL RE-EMERGE SATURDAY INTO SUNDAY. IT DOES APPEAR BASED ON ENSEMBLE MEANS THAT THE RIDGE LIFTS NE SATURDAY-SUNDAY AS THE CLOSED LOW IS RECAPTURED BY THE MARITIME FLOW DEAMPLIFYING AS AN OPEN-WAVE MONDAY-TUESDAY. PROGRESS OF AN ACCOMPANYING WARM- FRONTAL BOUNDARY ALONG WHICH THERE IS AN INCREASING UPSLOPE MAGNITUDE OF HIGHER THETA-E AIR BENEATH GROWING DIFFLUENCE ALOFT WARRANTS CHANCE POPS OVER THE MAJORITY OF THE AREA BEGINNING SATURDAY NIGHT. WILL GO AHEAD WITH SOME ELEVATED THUNDER CHANCES BUT KEEP THEM ISOLATED AS INSTABILITY APPEARS MARGINAL IN A MODERATELY SHEARED ENVIRONMENT. SUNDAY INTO MONDAY... LIKELY RAIN WITH EMBEDDED THUNDER AND HEAVIER SHOWERS AS AN ENHANCED H925-85 FLOW WRAPS CYCLONICALLY AROUND THE DEAMPLIFYING CLOSED-LOW NE OF THE REGION. A QUASI-TROWALING SETUP COLLOCATED WITH STRONG CONVERGENT ISENTROPIC-UPSLOPE SIGNATURES BENEATH DIFFLUENCE ALOFT... THE POTENTIAL FLY-IN-THE-OINTMENT COULD BE THE POSSIBILITY OF THE GREATER ENHANCED FORCING REMAINING W OF THE REGION ASSOCIATED WITH THE DEAMPLIFYING CLOSED-LOW OVER THE E GREAT LAKES AND/OR THE MODEL CONSENSUS OF NEW ENGLAND BEING BENEATH THE RIGHT-EXIT REGION OF THE UPPER-LEVEL JET...YIELDING A LESS FAVORABLE AREA OF LIFT. ASIDE...THE APPARENT LOW-MID LEVEL LIFT AND CONVERGENCE OF THETA-E YIELDS THE LIKELIHOOD OF RAIN. BUT THE QUICKLY-FOLLOWING PUNCH OF DRIER AIR WRAPPING INTO THE OCCLUDING SYSTEM MAKES THE WET-WEATHER PERIOD BRIEF. MOST OF THE ACTIVITY MAY RESIDE ON SUNDAY WITH DRY WEATHER PREVAILING SUNDAY NIGHT. ONLY A RENEWED CHANCE MAY EMERGE ON MONDAY ASSOCIATED WITH THE COMMA- HEAD TROWAL OF THE LOW WHERE H85-5 TEMPERATURES DROP CONSIDERABLY. H5 TEMPERATURES NEAR -20C. FOCUS ALONG A COLD FRONT AS POSSIBLY THE BOUNDARY-LAYER DESTABILIZES AHEAD SUBSEQUENT OF THE PUNCH OF DRY AIR COULD RESULT IN SOME LOW-TOPPED ACTIVITY. SOME SPATIAL VARIABILITY WITH RESPECT TO ATMOSPHERIC FEATURES THUS ONLY WILLING TO GO WITH CHANCE POPS MAINLY OUT TO THE W. WILL GO WITH AT OR BELOW-AVERAGE TEMPERATURES FOR THE PERIOD. PRESENTLY NOT SEEING MUCH IN THE WAY OF IMPACTS WITH RESPECT TO THE WET-WEATHER. HIGHER THETA-E VALUES LOOK TO REMAIN OFFSHORE WITHIN THE ANTICYCLONIC BRANCH OF THE WARM-CONVEYOR BELT...ALSO GREATER INSTABILITY. TUESDAY AND BEYOND... DRY WEATHER AS RIDGING PROCEEDS PER AN ENSEMBLE-WEIGHTED FORECAST. WILL LEAN TOWARDS AN ABOVE-AVERAGE TEMPERATURE FORECAST IN AGREEMENT WITH THE CLIMATE PREDICTION CENTER. CONTINUED STRONG SIGNALS OF SW- FLOW PREVAILING ALOFT ADVECTING NE ACROSS THE REGION A WARM-HUMID AIRMASS. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH THURSDAY/... THROUGH 00Z...VFR. ISOLD SHOWERS OR PERHAPS A TSTM IN W NEW ENG. TONIGHT...MODERATE CONFIDENCE. AREAS OF IFR/LIFR STRATUS AND PATCHY FOG LIKELY DEVELOPING TONIGHT...ESPECIALLY NEAR THE S COAST. MOSTLY VFR ELSEWHERE WITH SOME PATCHY MVFR FOG IN SPOTS. WEAKENING LINE OF SHOWERS/TSTMS MOVING INTO W MA AND N CT THIS EVENING WITH LOW PROB OF A BRIEF SHOWER/TSTM IN THE COASTAL PLAIN OVERNIGHT. THURSDAY...MODERATE CONFIDENCE. IFR CONDITIONS ALONG THE S COAST IMPROVING TO MVFR/VFR. OTHERWISE...VFR GRADUALLY LOWERING TO MVFR AS SHOWERS AND SCT TSTMS DEVELOP. FOCUS FOR SHOWERS/TSTMS WILL INITIALLY BE ACROSS E CT/RI AND SE MA IN THE MORNING...THEN GRADUALLY SHIFTING INTO WESTERN NEW ENG IN THE AFTERNOON. LOCALLY HEAVY RAINFALL POSSIBLE. THURSDAY NIGHT...MODERATE CONFIDENCE. CONDITIONS LOWERING TO IFR IN SHOWERS/TSTMS AND PATCHY FOG. LOCALLY HEAVY RAINFALL POSSIBLE. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. OUTLOOK /FRIDAY THROUGH MONDAY/... FRIDAY...MODERATE CONFIDENCE. MVFR-IFR MIX ALONG WITH -SHRA LIFTS E ALLOWING CONDITIONS TO IMPROVE THROUGH THE DAY. N-WINDS WITH THE POSSIBILITY OF 20 KT GUSTS ACROSS THE E-COAST. SATURDAY...MODERATE CONFIDENCE. VFR. WINDS VEERING E/SE. DRY FORECAST. SUNDAY...MODERATE CONFIDENCE. MVFR-IFR MIX WITH E/SE-ONSHORE FLOW. RAIN LIKELY ACROSS THE REGION. MAY ALSO CONTEND WITH SOME LLWS IMPACTS. MONDAY...MODERATE CONFIDENCE. IMPROVING TO VFR BEGINNING SUNDAY NIGHT. W/SW-WINDS WITH GUSTS UP TO 20 KTS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE. STILL EXPECT SOME G25 KT ACROSS NEARSHORE WATERS NEAR CAPE COD THROUGH THE REST OF THE AFTERNOON ASSOCD WITH MODEST LOW LEVEL JET SO WE WILL CONTINUE THE SMALL CRAFT ADVISORY. THE JET MOVES EAST TONIGHT AND WINDS WILL DIMINISH. VSBYS LOWERING IN PATCHY FOG TONIGHT S COASTAL WATERS. THU...WINDS BECOME NE LESS THAN 20 KT ACROSS E MA COASTAL WATERS AS FRONT MOVES THROUGH BUT REMAINING S/SE OVER SOUTHERN WATERS. VSBYS REDUCED IN SHOWERS AND POSSIBLE TSTMS AND FOG...ESPECIALLY IN THE MORNING. THU NIGHT...MAINLY E/NE WINDS BELOW SCA...BUT THERE IS LOW PROB OF GUSTY NE WINDS DEVELOPING LATE ACROSS NE MA COASTAL WATERS. VSBYS REDUCED AT TIMES IN SHOWERS/POSSIBLE TSTMS AND FOG. OUTLOOK /FRIDAY THROUGH MONDAY/... FRIDAY...MODERATE CONFIDENCE. LOW PRESSURE LIFTING E. SHOWERS LINGER ACROSS THE WATER ALONG WITH THE POSSIBILITY OF FOG. N-WINDS PREVAILING BACKING OUT OF THE NW. INITIALLY COULD SEE GUSTS UP TO 25 KTS ACROSS THE E-WATERS LENDING TO SEAS IN EXCESS OF 5-FEET. SMALL-CRAFT ADV MAY BE WARRANTED. SATURDAY...MODERATE CONFIDENCE. A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET. SUNDAY...MODERATE CONFIDENCE. DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT THE CHANCE OF RAIN ALONG WITH INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS POSSIBLE. WAVE HEIGHTS BUILDING IN EXCESS OF 5-FEET PLAUSIBLE. MONDAY...MODERATE CONFIDENCE. THOUGH IMPROVING SUNDAY NIGHT...WINDS BACK OUT OF THE W/SW AND REMAIN ROBUST WITH A STRONG AREA OF LOW PRESSURE SITUATED WELL TO THE W ACROSS THE INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE SEAS REMAIN AT OR IN EXCESS OF 5-FEET ON THE WATERS. && .CLIMATE... RECORD HIGH TEMPERATURES FOR WEDNESDAY...9/9 BOS...91 IN 1971 PVD...91 IN 1971 ORH...90 IN 1915 BDL...91 IN 2002 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR ANZ250. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...KJC SHORT TERM...KJC LONG TERM...SIPPRELL AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL CLIMATE...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
148 PM EDT WED SEP 9 2015 .SYNOPSIS... HIGH PRESSURE SOUTH OF NEW ENGLAND WILL PUSH OFFSHORE LATE TODAY THROUGH THURSDAY. A COLD FRONT WILL APPROACH LATE THIS AFTERNOON...SLOWLY CROSSING THE REGION TONIGHT AND THURSDAY...BEFORE STALLING ACROSS SOUTHEAST MASSACHUSETTS BY THURSDAY NIGHT. EXPECTING WIDESPREAD SHOWERS AND SOME THUNDERSTORMS...ALONG WITH HEAVY RAINFALL AT TIMES...WHICH MAY CAUSE LOCALIZED FLOODING THURSDAY NIGHT INTO FRIDAY. A BRIEF LULL FOLLOWS FOR SATURDAY PRIOR TO ANOTHER POTENTIAL BATCH OF RAIN SUNDAY INTO MONDAY. A WARM AND DRY PATTERN LOOKS TO PREVAIL INTO THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 145 PM UPDATE... RECORD MAX TEMP HAS BEEN SET AT BOS AND TIED AT BDL. SO FAR PVD IS ONE DEGREE SHY OF THE RECORD. RADAR SHOWS WIDELY SCT SHOWERS ACROSS E NY WITH MORE WIDESPREAD CONVECTION IN THE FORM OF A LINE ACROSS CENTRAL AND N NY ASSOCD WITH THE COLD FRONT. HRRR SHOWS A FEW SHOWERS AND PERHAPS A TSTM SPILLING INTO W NEW ENG MID/LATE AFTERNOON...BUT MAIN ACTIVITY ASSOCD WITH GOOD LOW LEVEL FRONTOGENESIS REMAINS TO THE WEST. MLCAPES UP TO 1000 J/KG ACROSS FAR W NW ENG AND E NY BUT INSTABILITY IS FORECAST TO WEAKEN RAPIDLY TOWARD 00Z SO EXPECT WE EXPECT WEAKENING LINE OF CONVECTION MOVING INTO THE REGION AROUND OR AFT 00Z. PREVIOUS DISCUSSION... STILL SOME STRATUS ALONG THE IMMEDIATE S COAST WHICH MAY TAKE UNTIL THE AFTERNOON TO BURN OFF...OTHERWISE MOSUNNY AND ANOTHER HOT/HUMID DAY. NOT QUITE AS HOT AS YESTERDAY...BUT MAXES WILL LIKELY REACH INTO THE LOWER 90S IN NE MA AND PORTIONS OF THE CT VALLEY AND WELL INTO THE 80S ELSEWHERE. BEST CHANCE OF AT LEAST TYING RECORD MAXES WILL BE AT BOS/BDL. IT WILL BE QUITE HUMID WITH DEWPOINTS UPPER 60S TO LOWER 70S SO HEAT INDICES WILL GET INTO THE LOW AND MID 90S. MODEST SW LOW LEVEL JET WILL LIKELY RESULT IN SOME GUSTS TO 25 MPH ACROSS SE NEW ENG. WEDGE OF VERY DRY MID LEVEL AIR ACROSS SNE THIS MORNING WILL MOVE OFFSHORE WITH COLUMN MOISTENING THROUGH THE AFTERNOON. AIRMASS DESTABILIZES WITH CAPES UP TO 1000 J/KG IN W NEW ENG AHEAD OF COLD FRONT WHICH MOVES THROUGH NEW YORK STATE THIS AFTERNOON. HI-RES GUIDANCE SUGGESTS A FEW SHOWERS/TSTMS COULD SPILL INTO W MA VERY LATE TODAY SO WILL HAVE SLIGHT CHC POPS IN THE AREA. 0-6KM SHEAR INCREASES TO ABOUT 25 KT SO AN ISOLD STRONG STORM IS POSSIBLE BUT SEVERE WEATHER NOT ANTICIPATED. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... COLD FRONT SLOWLY MOVES INTO THE REGION TONIGHT THROUGH MIDDAY THU...THEN WILL STALL ACROSS SOUTHEASTERN AREAS BY THU EVENING. WITH STEADY S-SW WIND FLOW IN PLACE...WILL SEE INCREASING MOISTURE FEED UP THE COAST. PWATS INCREASE UP TO 2 INCHES...SO WILL LIKELY SEE HEAVY RAINFALL ESPECIALLY ON THU AS THE FRONT SLOWS. WILL STILL SEE SOME MARGINAL INSTABILITY IN PLACE...SO SOME ISOLD CONVECTION REMAINS POSSIBLE. NOTING CAPES ACROSS NE CT/RI/SE MA AT AROUND 700- 800 J/KG...SO MIGHT SEE SOME GUSTY WINDS IN ANY THUNDERSTORMS THERE DURING THURSDAY AFTERNOON. EXPECT HIGHS ON THU RANGING FROM THE MID 70S WELL INLAND TO THE LOWER 80S ACROSS SE AREAS. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * POTENTIAL FOCUSED AREA OF HEAVY RAIN THURSDAY NIGHT INTO FRIDAY * THREAT OF URBAN / POOR-DRAINAGE FLOODING OVER NEW ENGLAND * A LULL PRIOR TO RENEWED ACTIVITY SUNDAY INTO MONDAY * LOOKING DRY AND WARMER INTO NEXT WEEK DISCUSSION... THURSDAY NIGHT THROUGH FRIDAY... 09/00Z GUIDANCE SUITE HAS NOT CHANGED MUCH FROM PREVIOUS THINKING. PLENTY OF SYNOPTIC FORCING SHOULD MEAN WIDESPREAD SHOWERS ACROSS SOUTHERN NEW ENGLAND FOR A PORTION OF THIS TIME PERIOD. HAVE HIGH CONFIDENCE IN MEASURABLE RAINFALL ACROSS MOST OF SOUTHERN NEW ENGLAND. STILL NEED TO IRON OUT WHAT THE UPPER LIMIT FOR RAINFALL WILL BE...AND WHERE IT WILL FALL. AT THIS POINT...IT STILL APPEARS THE AXIS FOR HEAVIEST RAINFALL WILL EXTEND NORTHEAST ACROSS NORTHERN CT AND WESTERN AND CENTRAL MA. THE MAJORITY OF RIVERS AND STREAMS ARE WELL BELOW NORMAL WITH RESPECT TO STREAMFLOWS. AS LAKES AND RESERVOIRS ARE ALSO LOW...THE SUBSEQUENT FOCUS REMAINS UPON URBAN AND POOR-DRAINAGE FLOODING. CONVECTIVE INSTABILITY LOOKS RATHER MARGINAL...SO NOT EXPECTING MANY STRONG THUNDERSTORMS. CANNOT COMPLETELY RULE OUT THAT POSSIBILITY THOUGH. NEAR SEASONABLE TEMPERATURES. THIS WEEKEND INTO EARLY NEXT WEEK... FAIRLY GOOD AGREEMENT AMONG THE 09/00Z MODELS HEADING INTO THIS WEEKEND...BREAKS DOWN TO SOME EXTENT SUNDAY INTO MONDAY. THE MAIN ISSUE WILL BE THE PROGRESS OF A MODEST UPPER LOW...AND HOW EFFECTIVE IT WILL BE TO SPAWN A COASTAL LOW OFF THE MID ATLANTIC COAST. BOTH THE GFS AND ECMWF HAVE A POTENT SHORTWAVE IN PLACE TO GENERATE THIS LOW PRESSURE...BUT HAVE RATHER DIFFERENT IDEAS ON ITS TRACK AND TIMING. HAVE MODERATE CONFIDENCE WE WILL SEE A PERIOD OF SHOWERS SOMETIME SUNDAY INTO MONDAY. HAVE LOW CONFIDENCE IN THE PRECISE TIMING. WILL JUST MENTION A CHANCE FOR SHOWERS SUNDAY INTO MONDAY...AND AWAIT FURTHER CLUES ON HOW THIS WINDOW COULD BE NARROWED IN LATER FORECASTS. NEXT WEEK... ENSEMBLE SOLUTIONS SIGNALING A RETURN TO A RIDGING PATTERN. COULD BE LOOKING AT ANOTHER PRONOUNCED HOT AND HUMID PERIOD...AS HIGH PRESSURE BUILDS S/E OF THE REGION. STILL HAVE RATHER LOW CONFIDENCE IN THE FORECAST DETAILS. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH THURSDAY/... THROUGH 00Z...VFR. ISOLD SHOWERS OR PERHAPS A TSTM IN W NEW ENG. TONIGHT...MODERATE CONFIDENCE. AREAS OF IFR/LIFR STRATUS AND PATCHY FOG LIKELY DEVELOPING TONIGHT...ESPECIALLY NEAR THE S COAST. MOSTLY VFR ELSEWHERE WITH SOME PATCHY MVFR FOG IN SPOTS. WEAKENING LINE OF SHOWERS/TSTMS MOVING INTO W MA AND N CT THIS EVENING WITH LOW PROB OF A BRIEF SHOWER/TSTM IN THE COASTAL PLAIN OVERNIGHT. THURSDAY...MODERATE CONFIDENCE. IFR CONDITIONS ALONG THE S COAST IMPROVING TO MVFR/VFR. OTHERWISE...VFR GRADUALLY LOWERING TO MVFR AS SHOWERS AND SCT TSTMS DEVELOP. FOCUS FOR SHOWERS/TSTMS WILL INITIALLY BE ACROSS E CT/RI AND SE MA IN THE MORNING...THEN GRADUALLY SHIFTING INTO WESTERN NEW ENG IN THE AFTERNOON. LOCALLY HEAVY RAINFALL POSSIBLE. THURSDAY NIGHT...MODERATE CONFIDENCE. CONDITIONS LOWERING TO IFR IN SHOWERS/TSTMS AND PATCHY FOG. LOCALLY HEAVY RAINFALL POSSIBLE. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/... THURSDAY NIGHT INTO FRIDAY...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN TIMING. A MIX OF LOW-END VFR TO IFR. IFR...ESPECIALLY WITH +RA/TSRA FORECAST. S FLOW BACKING N OVER TIME. IMPROVING FRIDAY NIGHT. SATURDAY...MODERATE CONFIDENCE. VFR. WINDS VEERING E/SE. SUNDAY...LOW CONFIDENCE. LOW-END VFR TO IFR WITH INCREASING CHANCES OF RAIN. E WINDS INCREASE...THEN BACK W/NW WITH TIME. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH THURSDAY/...HIGH CONFIDENCE. 1015 AM UPDATE... WE EXPANDED THE SCA TO THE NEARSHORE WATERS ADJACENT TO CAPE COD WHERE A FEW G25 KT EXPECTED THROUGH THE AFTERNOON. SW WINDS WILL CONTINUE THROUGH THE PERIOD. WILL SEE GUSTS UP TO 25 KNOTS AND SEAS AROUND 5 FT ON THE EASTERN OUTER WATERS THIS AFTERNOON THROUGH AROUND MIDNIGHT TONIGHT. SMALL CRAFT HAS BEEN ISSUED FOR THIS AREA. SOME GUSTS TO AROUND 20 KT POSSIBLE THIS AFTERNOON AND EVENING ALONG THE S COASTAL NEAR SHORE WATERS. WINDS BECOME LIGHT S-SW THOUGH MAY BE ONSHORE ALONG THE EASTERN NEAR SHORE WATERS THU. PATCHY FOG DEVELOPS TONIGHT WITH REDUCED VSBYS. SHOWERS DEVELOP FROM S-N OVERNIGHT TONIGHT...WITH LOW RISK OF ISOLD TSTMS. BEST SHOT FOR SHOWERS/ISOLD TSTMS WILL OCCUR DURING THU. FOG WILL ALSO LINGER. OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/... THURSDAY NIGHT INTO FRIDAY...MODERATE CONFIDENCE. LOW PRESSURE SHOULD PASS ACROSS SOUTHERN NEW ENGLAND. INCREASING SOUTH WINDS AHEAD OF THIS LOW COULD GENERATE SEAS APPROACHING 5 FEET ON THE E WATERS FOR THE LATE THURSDAY INTO FRIDAY PERIOD. IT IS MORE LIKELY THESE BUILDING SEAS WILL DEVELOP IN THE NORTHEAST FETCH ONCE THIS LOW PRESSURE IS FARTHER OFFSHORE. WILL SEE SOME IMPROVEMENT INTO SATURDAY MORNING. SATURDAY...MODERATE CONFIDENCE. WINDS VEERING E/SE. GOOD BOATING WEATHER PREVAILS WITH SEAS BELOW 5 FEET. SUNDAY...LOW CONFIDENCE. ANOTHER AREA OF LOW PRESSURE AND RAIN. TRACK UNCERTAIN. COULD SEE IMPACTS ON THE WATERS...THOUGH THEY MAY REMAIN MORE SOUTH AND EAST COMPARED TO THURSDAY-FRIDAY. && .CLIMATE... RECORD HIGH TEMPERATURES FOR WEDNESDAY...9/9 BOS...91 IN 1971 PVD...91 IN 1971 ORH...90 IN 1915 BDL...91 IN 2002 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR ANZ250. && $$ SYNOPSIS...BELK/EVT NEAR TERM...KJC SHORT TERM...EVT LONG TERM...BELK AVIATION...BELK/KJC MARINE...BELK/EVT CLIMATE...
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
1256 PM CDT WED SEP 9 2015 ...Updated aviation section... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT WED SEP 9 2015 The main forecast challenge for early this morning is areas of fog, and or stratus and how dense. Moist weak northeasterly upslope flow and with clear skies is allowing for good radiational cooling, and causing areas of ground fog to develop and some stratus. Will carry areas of fog in most areas this morning, but may need a dense fog advisory in places especially near and west of Dodge City where the NAM and the RAP model shows the highest boundary layer relative humidity. The HRRR model also shows patchy dense fog in the Garden City area. After the fog burns off by mid morning, expect clearing skies and highs in the mid 80s. A surface high pressure ridge will move east while a trough of low pressure develops in the lee of the Rockies. Light and variable winds this morning will become southeast to southerly at 10 mph with 10 to 20 mph far west. For tonight, expect mainly clear skies. A few thunderstorms could develop late across the I-70 corridor as a jet streak moves in. Will carry some small chances for rainfall, towards dawn. Overnight lows will be in the lower 60s with light southeast winds becoming south around 8 to 12 mph. .LONG TERM...(Thursday THROUGH Tuesday) ISSUED AT 339 AM CDT WED SEP 9 2015 For Thursday, an upper level shortwave trough in northwest flow aloft will move across western Kansas pushing a cold front to near Hays to Garden City and Elkhart by late afternoon. Ahead of the cold front, warmer and moist south winds of 15 to 25 mph, will push highs to around 90. Most models have thunderstorms developing by afternoon ahead of the cold front, with a possible MCS (Mesoscale Convective Complex) developing near and east of Dodge City by late afternoon and evening. The cold front will continue to push across western Kansas overnight with numerous thunderstorms developing. Some low stratus is also suggested towards dawn behind the cold front. Will carry around 50 percent chances in the afternoon and evening with lesser chances north of Garden City where dewpoints are much lower. Forecast instability is around 2000-3000 J/KG, but the NAM is much higher and with dewpoints in the upper 60s. With 30kt at mid levels and around 50 to 60kt aloft there could be some severe thunderstorms with large hail from quarter to half dollar size, and strong winds over 60 mph. For Friday into next Tuesday, a dry period is forecast. A large upper level trough will continue to dig into the Upper Midwest and Mississippi Valley with much cooler surface high pressure moving into the Plains. Highs on Friday and Saturday will be in the mid to upper 70s. As the upper trough moves away from the region Sunday into Tuesday, a warming trend will move back into the High Plains with highs in the low 80s on Sunday, then mid to upper 80s on Monday and Tuesday. Overnight lows will be in the 50s into Sunday morning, the gradually warm to 60 to 65 degrees on Monday and Tuesday morning. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Thursday AFTERNOON) ISSUED AT 1253 PM CDT WED SEP 9 2015 Low clouds will dissipate over the next couple of hours leading to VFR conditions for the remainder of the afternoon into the evening hours. Winds will generally be from the south around 8 knots as lee troughing redevelops across eastern Colorado. && .PRELIMINARY POINT TEMPS/POPS... DDC 85 62 89 60 / 0 10 40 40 GCK 85 61 90 59 / 0 0 30 30 EHA 87 63 91 60 / 10 10 20 20 LBL 86 62 92 61 / 0 10 30 40 HYS 87 61 89 60 / 0 20 30 30 P28 85 63 89 64 / 0 10 20 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Hovorka_42
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
310 PM EDT WED SEP 9 2015 .SHORT TERM (NOW THROUGH THURSDAY NIGHT)... ISSUED AT 245 PM EDT WED SEP 9 2015 AS OF MID AFTERNOON...WATER VAPOR IMAGERY AND 500 MB HEIGHTS SHOWED A SHORTWAVE TROUGH EXTENDING FROM THE GREAT LAKES DOWN ALONG THE MISSISSIPPI RIVER...JUST WEST OF CENTRAL KENTUCKY. AT THE SURFACE...THE ENVIORNMENT IS CHARACTERIZED BY WARM AND MOIST AIR WITH DEWPOINTS IN THE LOW 70S. A COLD FRONT LIED ALONG THE OHIO RIVER...SLOWLY MOVING EAST THROUGH THE AREA. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY IN THE WARM SECTOR WILL CONTINUE THROUGH THE LATE AFTERNOON HOURS. THESE STORMS WILL BE CAPABLE OF PROUDCING BRIEF BUT VERY HEAVY RAINFALL GIVEN THE HIGH PWATS IN THE AREA. SOME GUSTY WINDS ARE POSSIBLE AS WELL. HI-RES MODELS SUCH AS THE HRRR AND 12Z SPC WRF ARE IN GOOD AGREEMENT SHOWING THE HIGHEST CHANCES NOW THROUGH EARLY EVENING...THEN A DECREASE IN COVERAGE AS THE UPPER SHORTWAVE TROUGH KICKS THE FRONT EAST THROUGH THE AREA. A SECONDARY LOW PRESSURE AND TROUGH NEAR MEMPHIS WILL TRACK THROUGH CENTRAL TN TO SOUTHEAST KY OVERNIGHT...KEEPING SOME SHOWERS AND STORMS IN THE FORECAST MAINLY OVERNIGHT FOR THE SOUTHERN FORECAST AREA. AREAS NORTH OF THE KY PARKWAYS INTO SOUTHERN INDIANA WILL PROBABLY SEE THE END OF THE RAIN FROM THIS SYSTEM THIS EVENING OR EARLY OVERNIGHT. LOW CLOUDS AND/OR FOG IS A CONCERN OVERNIGHT INTO THE THURSDAY MORNING COMMUTE AS THE BOUNDARY LAYER WILL REMAIN VERY MOIST WITH LIGHT WINDS. SREF PROBABIALITIES FOR LOW CLOUDS /500 FT OR LESS/ AND FOG ARE BETWEEN 40 AND 60 PERCENT. WILL HAVE TO WATCH FOR LOCALLY DENSE POCKETS OF FOG...ESPECIALLY IF THERE IS ANY CLEARING OR BREAKS IN THE CLOUDS TOWARD SUNRISE. IMPROVING CONDITIONS CAN BE EXPECTED DURING THE DAY THURSDAY. SOME LINGERING SHOWERS AND MAYBE A THUNDERSTORM WILL BE POSSIBLE ALONG AND SOUTHEAST OF A LEXINGTON TO BOWLNG GREEN LINE DURING THE MORNING BUT THIS SHOULD QUICKLY MOVE EAST BY NOON. NORTHWEST WINDS WILL PICK UP...HELPING TO SCATTER OUT OR LIFT SOME OF THE CLOUDS IN THE AREA. LOOK FOR HIGHS RIGHT AROUND NORMAL IN THE LOW 80S. .LONG TERM (FRIDAY THROUGH WEDNESDAY)... ISSUED AT 305 PM EDT TUE SEP 8 2015 THE LONG TERM PERIOD WILL START OUT WITH A COLD FRONT PASSAGE ON FRIDAY BRINGING SHOWERS/STORMS TO THE AREA FRI/FRI NIGHT. ALTHOUGH THE OVERALL FORCING NEAR THE FRONT AND WIND SHEAR LOOK RELATIVELY WEAK, THERE MAY BE ENOUGH SFC INSTABILITY TO PRODUCE A FEW STRONG CELLS DURING THE AFTERNOON HOURS FRIDAY. OVERALL THOUGH, DON`T SEE A BIG THREAT FOR ORGANIZED STRONG TO SEVERE CONVECTION FOR FRIDAY. THE BIGGER STORY WITH THIS FRONT WILL BE THE STRONG UPPER LOW AND MUCH COOLER AIRMASS FOLLOWING IT. WITH THESE FEATURES IN PLACE FOR THE WEEKEND, LOOK FOR TEMPS TO BE 6 TO 12 DEGREES BELOW NORMAL. SATURDAY WE`LL HAVE PLENTY OF LOW CLOUDS AND LINGERING SHOWERS LIMITING HIGHS TO THE MID TO UPPER 60S. SOME MODEL DATA SUGGESTS PERHAPS WE COULD SEE AN ISLD RUMBLE OF THUNDER WITH THIN, SHALLOW INSTABILITY PRESENT IN THE SOUNDINGS. SHOWER ACTIVITY SHOULD CONTINUE INTO SAT NIGHT BEFORE GRADUALLY ENDING FROM WEST TO EAST SUN MORNING. HIGHS ON SUNDAY WILL BE SIMILAR TO SAT IN THE MID TO UPPER 60S. LOW TEMPERATURES THIS WEEKEND WILL RANGE FROM THE MID 40S TO LOWER 50S WITH THE COOLEST NIGHT BEING SUN NIGHT INTO MONDAY MORNING WHEN SKIES WILL BECOME CLEAR WITH THE HIGH PRESSURE CENTER OVER THE REGION. WE`LL REMAIN DRY MON-WED WITH RETURN FLOW BRINGING WARMER TEMPS BACK INTO THE REGION. HIGHS ON MONDAY WILL WARM BACK INTO THE LOWER 70S WITH UPPER 70S/LOWER 80S EXPECTED BY TUES/WED UNDER MOSTLY SUNNY SKIES. && .AVIATION (18Z TAF UPDATE)... ISSUED AT 1258 PM EDT WED SEP 9 2015 MAINLY SHOWERS WILL AFFECT THE TERMINALS THROUGH THE OVERNIGHT PERIOD. FOR THIS AFTERNOON...EXPECT COVERAGE TO BE MORE SCATTERED IN NATURE WITH BRIEF DROPS TO MVFR POSSIBLE. SO FAR ACTIVITY HAS HAD VERY LITTLE IN-CLOUD OR CLOUD TO GROUND LIGHTNING AND WITH LESS COVERAGE...OPTED TO REMOVE VCTS FOR THIS AFTERNOON. LARGER BAND OF RAIN SHOWERS WILL THEN SPREAD OVER SDF/LEX...BETWEEN 21-03Z WEST TO EAST. FOG/STRATUS BECOMES THE NEXT CONCERN AT ALL SITES FOR THE OVERNIGHT. GUIDANCE IS HITTING LOW CLOUDS PRETTY HARD WITH IFR CONDITIONS BASED ON A WELL SATURATED BOUNDARY LAYER. THE WIND FIELD WILL ALSO BE LIGHT AND MOISTURE DOES LINGER WITH THE FRONT NEARBY. AS SUCH...THIS ADDS CONFIDENCE TO WHAT THE GUIDANCE IS SUGGESTING...SO HAVE TRENDED CEILINGS LOWER /IFR AT BWG AND LEX/ BUT THIS MAY NEED TO GO LOWER IN FUTURE UPDATES. THERE MAY ALSO BE REDUCED VISIBILITY...POSSIBLY DENSE FOG AT BWG. THE MAIN PERIOD FOR THE FOG/STRATUS RESTRICTIONS WOULD BE 09-15Z. LOOK FOR SOME GRADUAL IMPROVEMENT WEST TO EAST DURING THE MORNING THURSDAY AS WINDS BECOME NORTHWESTERLY HELPING TO PUSH SLIGHTLY DRIER AIR IN. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ SHORT TERM........ZBT LONG TERM.........AMS AVIATION..........ZBT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
302 PM CDT WED SEP 9 2015 .SYNOPSIS... ISSUED AT 302 PM CDT WED SEP 9 2015 AS OF WEDNESDAY AFTERNOON THE UPPER AIR SYNOPTIC PATTERN OVER THE CONTINUED TO BE HIGHLIGHTED BY A BROAD TROUGH ASSOCIATED WITH A LOW SLOWLY MOVING TOWARD HUDSON BAY. THIS HAS THE NORTHERN AND CENTRAL PLAINS IN RELATIVELY FAST NORTHWEST FLOW ALOFT. COOLER AIR IN THE MID TO UPPER LEVEL OF THIS FLOW FOSTERED AN ENVIRONMENT CHARACTERIZED BY STEEP LAPSE RATES AND ELEVATED INSTABILITY...WHICH HAS AIDED IN THE FORMATION AND PERSISTENCE OF ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY IN CENTRAL NEBRASKA LATE IN THE MORNING AND EARLY THIS AFTERNOON. AT THE SURFACE...A WEAK FRONT WAS SLOWLY MOVING EAST ACROSS THE CWA. AS OF 20Z THE FRONT EXTENDED FROM JUST EAST OF IMPERIAL AND NORTH PLATTE...NORTHEASTWARD TO NEAR AINSWORTH. DRY WESTERLY WINDS BEHIND THE FRONT HAD DEWPOINTS DROPPING INTO THE 30S AND 40S ACROSS THE PANHANDLE AND WESTERN SANDHILLS. AHEAD OF THE FRONT WINDS WERE SOUTHERLY AND DEWPOINTS REMAINED IN THE UPPER 50S AND 60S...WITH A CU FIELD DEVELOPING AS THE BOUNDARY LAYER BECOMES MORE UNSTABLE. TEMPERATURES WERE GENERALLY IN THE MID 80S. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 302 PM CDT WED SEP 9 2015 THUNDERSTORMS IN CENTRAL AND NORTH CENTRAL NEBRASKA SHOULD CONTINUE TO SLOWLY PUSH EAST THROUGH THE REMAINDER AFTERNOON. CONVECTIVE ACTIVITY HAS ACCELERATED OVER CENTRAL ROCK AND HOLT COUNTY. SOME LOCATIONS ARE RECEIVING HEAVY RAINFALL DUE TO TRAINING STORMS...HOWEVER LATEST FFG IN THIS AREA IS QUITE HIGH. ADDITIONAL SURFACE BASED SHOWERS AND THUNDERSTORM DEVELOPMENT HAS BEGUN IN FAR SOUTHWEST NEBRASKA AND NORTHWEST KANSAS ALONG AN EASTWARD PROGRESSING FRONT. HRRR HAS FAVORED AREAS JUST EAST OF A NORTH PLATTE TO THEDFORD MUCH OF THE DAY...AND THIS MATCHES UP WELL WITH THE DEVELOPING CU FIELD ON SATELLITE SO THE FORECAST LOOKS ON TRACK. UPPER LEVEL FORCING IS TOUGH TO DISCERN SO THE SPATIAL EXTENT OF THE NEW CONVECTION IS NOT EXPECTED TO BE EXPANSIVE. MLCAPE VALUES 1500 J/KG AND 35-40 KTS DEEP LAYER SHEAR WILL SUPPORT A FEW STRONG TO SEVERE STORMS...HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED. THUNDERSTORMS PUSH EAST THIS EVENING AND BEGIN TO WANE AFTER DARK WITH THE LOSS OF HEATING AND INSTABILITY. WEAK SHORTWAVE TROUGH DIVES SOUTHEAST THROUGH THE AREA OVERNIGHT. WINDS BECOME EASTERLY AS THE FRONT SLOWLY PUSHES JUST SOUTHEAST OF THE CWA AND A LEE SIDE SURFACE LOW DEEPENS IN NORTHEAST COLORADO. THIS WILL ALLOW LOW LEVEL MOISTURE TO CREEP BACK WESTWARD...WITH ANOTHER ROUND OF FOG/STRATUS POSSIBLE FOR SOUTHWEST INTO CENTRAL NEBRASKA. DID NOT INCLUDE PATCHY FOG IN THE FORECAST AT THIS TIME SINCE MODEL GUIDANCE HAS BEEN SOMEWHAT INCONSISTENT WITH COVERAGE AND SEVERITY OF VISIBILITY RESTRICTIONS. THE MOST FAVORABLE AREAS FOR LOCALLY DENSE FOG FORMATION WILL LIKELY BE WHERE PRECIPITATION FALLS LATER THIS EVENING. AN AREA OF SURFACE HIGH PRESSURE BEGINS TO DROP OUT OF ALBERTA AND INTO THE NORTHERN PLAINS ON THURSDAY. THIS WILL PUSH TEMPERATURES DOWN A FEW DEGREES WITH HIGHS RANGING FROM THE LOW 70S TO LOW 80S ACROSS THE CWA. MODELS ADVERTISE LIGHT QPF LATE IN THE AFTERNOON AS A MID-LEVEL JET STREAK NOSES INTO THE CENTRAL PLAINS...BUT DID NOT ADD ANY MENTION OF POPS TO THE SHORT TERM FORECAST JUST YET AS THE BETTER CHANCES LOOK TO BE AFTER 00Z FRIDAY. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 302 PM CDT WED SEP 9 2015 THE NAM REMAINS IN AGREEMENT WITH CURRENT FORECAST WITH A DISTURBANCE DROPPING SOUTHEAST FROM SWRN SD INTO WRN NEBR OVERNIGHT. THE GFS IS FASTER WITH THIS DISTURBANCE AND REMAINS MOSTLY DRY. THEREFORE KEPT POPS LIMITED TO 20 PERCENT WEST OF A LINE FROM GORDON THROUGH BROKEN BOW. KEPT VERY NEAR PREVIOUS HIGHS FRIDAY AS EASTERLY WINDS BECOME SOUTHEAST BY AFTERNOON AND WEAK WAA WILL NOT KICK IN UNTIL AFTERNOON. THERE COULD ALSO BE A FEW SHOWERS AND CLOUDINESS LINGERING AS WELL. ON SATURDAY...A RETURN SOUTHERLY WIND RETURNS WITH HIGHS WARMING TO NEAR 80 ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO MID 70S. FOR SUNDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES. ZONAL FLOW ALOFT ACROSS THE CENTRAL PLAINS SUNDAY WILL PERSIST INTO MONDAY AS AN UPPER TROUGH DIGS INTO THE PACIFIC NORTHWEST. THIS WILL KEEP A THERMAL RIDGE ACROSS THE REGION WITH HIGHS RANGING IN THE 80S. ON TUESDAY...THE UPPER TROUGH WILL ADVANCE ACROSS MONTANA THROUGH COLORADO WITH STRONG HEATING TO OCCUR IN ADVANCE ACROSS THE CENTRAL PLAINS. FORECAST HIGH ARE 85 TO 90...ALTHOUGH THE POTENTIAL IS THERE FOR HIGHS TO EXCEED 90 IN SOME AREAS OF WRN NEBR. A COLD FRONT TUESDAY NIGHT TO COOL BACK HIGHS TO NEAR 75 NORTH AND NEAR 80 SOUTH. THE 12Z ECMWF HOWEVER IS MUCH WEAKER WITH THE POST FRONTAL COOLDOWN AND SUGGESTS 80S STILL POSSIBLE. MAINLY DRY THROUGH THE EXTENDED PERIODS...EXCEPT A SLIGHT CHANCE ERN PNHDL TUESDAY AFTN...AND MOST AREAS TUESDAY NIGHT. LOOKS DRY BEHIND THE FRONT FOR WEDNESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1223 PM CDT WED SEP 9 2015 MAIN CONCERNS FOR THE CURRENT TAF PERIOD IS THE ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING...AND THE POTENTIAL FOR SUB-VFR CIGS/VISBYS LATE TONIGHT AND EARLY THURSDAY MORNING. A LINE OF THUNDERSTORMS ARE ONGOING EARLY THIS AFTERNOON IN PARTS OF CENTRAL NEBRASKA...WITH REDEVELOPMENT TO THE WEST AND NORTH POSSIBLE LATER THIS AFTERNOON AND EVENING. DID NOT FEEL CONFIDENT ENOUGH IN THE SPATIAL EXTENT OF THUNDERSTORM ACTIVITY TO INCLUDE IN THE TAF AT KLBF. ALL MODEL GUIDANCE AND OBSERVATIONAL TRENDS SUGGEST THE ACTIVITY SHOULD REMAIN SOUTH AND EAST OF KVTN. FOG AND LOW STRATUS MAY DEVELOP OVERNIGHT...GENERALLY FROM SOUTHWEST INTO NORTH CENTRAL NEBRASKA...INCLUDING KLBF...KBBW...KONL. INTRODUCED MVFR CIGS/VISBYS INTO THE TAF TO SUGGEST THE POTENTIAL...ALTHOUGH THEY MAY NEED TO BE LOWERED INTO IFR SHOULD FORECASTER CONFIDENCE INCREASE. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MARTIN SHORT TERM...MARTIN LONG TERM...ROBERG AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
310 PM MDT WED SEP 9 2015 .SYNOPSIS... SCATTERED THUNDERSTORMS OVER CENTRAL NEW MEXICO WILL TAPER OFF THIS EVENING. THE COVERAGE OF STORMS WILL FOCUS OVER SOUTHWEST NEW MEXICO ON THURSDAY. DRIER AIR SETTLING INTO NORTHERN NEW MEXICO TONIGHT AND THURSDAY NIGHT WILL ALLOW LOW TEMPERATURES TO SETTLE INTO THE 30S AND 40S. A BACK DOOR COLD FRONT WILL SHIFT DOWN THE EASTERN PLAINS ON FRIDAY ALLOWING FOR ANOTHER UPTICK IN STORMS. HIGH TEMPERATURES WILL FALL BELOW NORMAL WITH MANY AREAS STAYING IN THE 70S. ISOLATED STORMS ARE EXPECTED OVER THE WEEKEND BEFORE THE NEXT INCREASE IN COVERAGE DEVELOPS MONDAY AND TUESDAY. && .DISCUSSION... THE COMBINATION OF A 40-50KT 300MB JET CORE AND MOIST UNSTABLE UPSLOPE FLOW ALONG THE EAST SLOPES OF THE CENTRAL MT CHAIN TODAY HAS LED TO A FEW STRONG TO LOCALLY SEVERE STORMS. SPC SSEO PICKED UP ON THE COVERAGE AREA VERY WELL. HRRR AND LOCAL WRF SHOW THIS ACTIVITY TAPERING OFF DURING THE EVENING WHILE DRYING TAKES PLACE FROM NORTH TO SOUTH. SFC DEWPOINTS FROM THE NAM12 SHOW UPPER 20S/ LOW 30S TONIGHT ACROSS THE NW HALF OF THE STATE...WHICH COMBINED WITH RADIATIONAL COOLING WILL LEAD TO CHILLY TEMPS. ANGEL FIRE IS EXPECTED TO HIT FREEZING FOR THE 1ST TIME SINCE AUGUST 5TH. THE AXIS FOR MOIST INSTABILITY WILL SHIFT FARTHER SOUTH THURSDAY INTO SW NM WHILE DRY AIR ALOFT CONTINUES PRESSING S/SE OVER NORTHERN NM. A FEW STORMS ARE STILL LIKELY AS WEAKLY FAVORABLE UPPER LEVEL JET DYNAMICS DRIFT SOUTH OUT OF COLORADO. AT THE SURFACE THE FIRST SIGNS OF A BACK DOOR FRONT WILL FLIRT WITH THE FAR NE PLAINS THUS PROVIDING YET ANOTHER FORCING MECHANISM WITHIN COLFAX AND UNION COUNTIES. THIS FRONT WILL SURGE INTO EASTERN NM AND THRU GAPS IN THE CENTRAL MT CHAIN FRIDAY. MEANWHILE A 590DM H5 HIGH CENTER WILL BECOME POSITIONED OVERHEAD AND FOCUS MORE TERRAIN DOMINATED STORM COVERAGE FRIDAY THROUGH THE WEEKEND. EXTENDED MODEL GUIDANCE IS GOING TO HAVE A DIFFICULT TIME WITH THE REMNANTS OF HURRICANE LINDA NEXT WEEK AS SEVERAL DISORGANIZED UPPER LEVEL VORT FEATURES TAKE SHAPE ALONG THE WEST COAST. FOR NOW IT APPEARS MONDAY/TUESDAY COULD FEATURE AN UPTICK IN STORM COVERAGE AS A PORTION OF THE 700-500MB MOISTURE AXIS CROSSES NM. GUYER && .FIRE WEATHER... A NEW CENTROID OF HIGH PRESSURE HAS TAKEN SHAPE OVER THE GREAT BASIN. THIS WILL FUNNEL DRIER AIR OVER NM FROM THE NORTHWEST WITH MINIMUM HUMIDITIES FALLING A FEW TO 14 DEGREES ACROSS THE FORECAST AREA THURSDAY. SINCE LOW LEVEL FLOW WILL ALSO TAKE ON MORE OF A SOUTHWESTERLY COMPONENT ON THURSDAY...THERE WILL BE A DOWNTICK IN SHOWER AND THUNDERSTORM COVERAGE WITH MAINLY ISOLATED ACTIVITY FAVORING LOCATIONS ALONG AND EAST OF THE CONTINENTAL DIVIDE. A STRONGER BACK DOOR COLD FRONT FRIDAY WILL BRING WITH IT MORE MOISTURE WITH AN UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY ALONG AND EAST OF THE CENTRAL MOUNTAIN CHAIN DURING THE AFTERNOON...THEN AS FAR WEST AS THE CONTINENTAL DIVIDE DURING THE EVENING. THIS FRONT IS FORECAST TO PRODUCE A MODERATELY GUSTY EAST CANYON WIND IN THE MIDDLE AND LOWER RIO GRANDE VALLEY FRIDAY AND FRIDAY NIGHT. ANOTHER CROP OF THUNDERSTORMS IS EXPECTED ALONG AND EAST OF THE CONTINENTAL DIVIDE ON SATURDAY AS MOISTURE RECYCLES...BUT THERE WILL BE A DOWNTICK IN COVERAGE. THE UPPER HIGH IS FORECAST TO MIGRATE SOUTHEASTWARD TO AROUND THE NM BOOT HEEL ON SUNDAY...THEN TO THE SE OF NM ON MONDAY AS AN UPPER LEVEL TROUGH DEEPENS INTO A LOW PRESSURE SYSTEM ON THE WEST COAST AND EJECTS SOME OF ITS SHORTWAVE ENERGY INLAND ACROSS THE CENTRAL ROCKIES. THERE ARE SIGNIFICANT DISAGREEMENTS BETWEEN MODELS ON THE TRACK AND TIMING OF THIS LOW AND THE SHORTWAVES...BUT THE GFS AND ECMWF DO AGREE FAIRLY WELL ON A TAP OF SUBTROPICAL MOISTURE IN STRENGTHENING SW FLOW ALOFT REACHING SW AREAS SUNDAY AND MUCH OF CENTRAL AND WESTERN NM MONDAY. A ROLLER COASTER OF TEMPERATURES IS EXPECTED THROUGH THE WEEKEND. HIGH TEMPERATURES WILL WARM A FEW TO 5 DEGREES THURSDAY...THEN FALL WITH THE BACK DOOR COLD FRONT FRIDAY. FALLING TEMPERATURES WILL CONTINUE IN THE WEST THROUGH SATURDAY...WHILE EASTERN READINGS BEGIN TO REBOUND. HIGH TEMPS SHOULD THEN WARM SUNDAY AS THE CENTER OF HIGH PRESSURE DRAWS NEAR...THEN BEGIN TO FALL IN THE WEST AGAIN MONDAY AS BETTER MOISTURE ARRIVES. MINIMUM HUMIDITIES SHOULD FALL A FEW TO 22 PERCENT ON SUNDAY BEFORE BEGINNING TO REBOUND IN THE WEST ON MONDAY. HIGH HAINES VALUES IN THE 5 TO 6 RANGE ARE EXPECTED OVER NORTHWEST AND NORTH CENTRAL AREAS THURSDAY...THEN OVER NW AND WEST CENTRAL AREAS FRIDAY. EXTREME VALUES SHOULD ABATE EAST OF THE CONTINENTAL DIVIDE WITH THE ARRIVAL OF BETTER MOISTURE ON FRIDAY NIGHT AND SATURDAY...ONLY TO OVERSPREAD MOST LOCATIONS ALONG AND NORTH OF INTERSTATE 40 ON SUNDAY. NORTHEAST AREAS MAY CONTINUE TO BE AFFLICTED WITH HIGH HAINES ON MONDAY. POCKETS OF POOR VENTILATION WILL IMPACT WEST CENTRAL AREAS WEDNESDAY...THEN NORTH CENTRAL...CENTRAL AND SOUTHWEST AREAS THURSDAY. POCKETS OF POOR VENTILATION MAY LINGER INTO FRIDAY WEST OF THE CONTINENTAL DIVIDE AND OVER THE SANGRE DE CRISTOS...BUT VENTILATION LOOKS TO IMPROVE MOST PLACES SATURDAY AND ESPECIALLY SUNDAY. RATES SHOULD THEN STAY GOOD TO EXCELLENT MONDAY. 44 && .AVIATION... 18Z TAF CYCLE TRUSTED MESOSCALE MODELS DEPICT SLOW MOVING -SHRA/-TS FAVORING THE CENTRAL MT CHAIN AND ADJACENT E SLOPES...AS WELL AS NEW MEXICOS SOUTHERN HIGH TERRAIN TODAY. MOST OF THE ACTIVITY WILL DRIFT TO THE SE AROUND 5 TO 15 MPH...WHICH SHOULD EVENTUALLY TRACK CELLS NEAR KTCC AND KROW. MODELS ALSO SUGGEST A FEW CELLS WILL POP UP NEAR KSAF...KABQ...KAEG AND KGUP...THOUGH TS PROBABILITIES WERE LOW ENOUGH TO USE VCSH RATHER THAN VCTS IN THESE TAFS. A FEW ISOLD CELLS COULD LINGER INTO THE LATE NIGHT HOURS MAINLY ALONG AND S OF HWY 60. A MIXTURE OF WET AND DRY MICROBURSTS ARE EXPECTED TODAY WITH LOCALIZED AND ERRATIC WIND GUSTS NEAR 45 KT. 44 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 52 90 52 89 / 0 0 0 5 DULCE........................... 36 83 37 82 / 10 10 5 5 CUBA............................ 46 81 46 78 / 10 5 5 5 GALLUP.......................... 46 87 46 87 / 5 5 0 5 EL MORRO........................ 43 81 43 80 / 10 10 5 10 GRANTS.......................... 45 86 44 83 / 10 10 5 5 QUEMADO......................... 53 80 50 82 / 20 20 20 20 GLENWOOD........................ 56 77 54 83 / 30 30 30 20 CHAMA........................... 42 76 43 75 / 10 10 10 10 LOS ALAMOS...................... 58 81 58 79 / 10 10 5 10 PECOS........................... 55 78 54 73 / 20 10 10 30 CERRO/QUESTA.................... 51 78 50 75 / 20 20 10 30 RED RIVER....................... 38 72 39 66 / 20 20 10 40 ANGEL FIRE...................... 49 68 50 62 / 20 30 20 40 TAOS............................ 44 82 42 78 / 20 10 10 10 MORA............................ 50 75 51 68 / 30 30 20 30 ESPANOLA........................ 50 87 50 85 / 10 5 5 10 SANTA FE........................ 58 81 58 77 / 10 10 5 10 SANTA FE AIRPORT................ 54 87 55 83 / 10 10 5 10 ALBUQUERQUE FOOTHILLS........... 61 87 59 83 / 10 5 5 5 ALBUQUERQUE HEIGHTS............. 64 90 62 86 / 10 5 5 5 ALBUQUERQUE VALLEY.............. 59 91 58 88 / 10 5 0 5 ALBUQUERQUE WEST MESA........... 63 92 60 88 / 10 0 0 5 LOS LUNAS....................... 56 91 56 89 / 10 5 5 5 RIO RANCHO...................... 61 91 59 87 / 10 0 0 5 SOCORRO......................... 62 90 59 89 / 30 20 10 20 SANDIA PARK/CEDAR CREST......... 55 84 55 79 / 20 10 10 30 TIJERAS......................... 58 86 55 81 / 20 5 5 10 MORIARTY/ESTANCIA............... 49 85 49 81 / 20 10 10 30 CLINES CORNERS.................. 55 82 55 74 / 30 10 10 30 GRAN QUIVIRA.................... 58 81 55 78 / 40 20 20 30 CARRIZOZO....................... 62 84 59 83 / 40 30 20 20 RUIDOSO......................... 57 76 55 75 / 50 50 40 40 CAPULIN......................... 54 80 53 64 / 10 20 30 30 RATON........................... 49 87 51 74 / 10 20 20 30 SPRINGER........................ 51 86 52 74 / 10 10 20 30 LAS VEGAS....................... 50 83 49 74 / 30 30 20 30 CLAYTON......................... 59 88 58 70 / 10 10 30 30 ROY............................. 57 85 52 70 / 10 10 20 30 CONCHAS......................... 64 92 62 80 / 10 10 20 30 SANTA ROSA...................... 62 90 61 81 / 20 10 10 30 TUCUMCARI....................... 64 93 61 77 / 10 10 20 30 CLOVIS.......................... 63 89 61 80 / 20 10 10 30 PORTALES........................ 66 88 63 82 / 20 10 10 30 FORT SUMNER..................... 64 89 62 80 / 20 10 10 30 ROSWELL......................... 68 93 65 91 / 30 10 10 30 PICACHO......................... 62 86 60 83 / 30 20 20 30 ELK............................. 61 76 58 76 / 40 30 30 30 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
316 PM EDT WED SEP 9 2015 .SYNOPSIS... LATE SUMMER WEATHER WILL BE IN PLACE TODAY WITH HIGH HUMIDITY AND SCATTERED THUNDERSTORMS. CLOUDS AND RAIN CHANCES REMAIN THROUGH LATE IN THE WEEK WITH THE SLOW APPROACH OF A COLD FRONT. THIS FRONT MAY STALL IN THE AREA UNTIL EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM WEDNESDAY...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE GENERALLY IN THE REGION THE HRRR HAD INDICATED BUT NOT THE COVERAGE IT WAS ADVERTISING. THE CONVECTION IS GENERALLY EAST OF A LINE FROM LUMBERTON TO MYRTLE BEACH TO GEORGETOWN. OVERNIGHT IT IS VERY HARD TO DETECT A SIGNIFICANT SHORTWAVE AS WE HAD LAST NIGHT. THE MODELS ARE SHOWING THE SURFACE LOW PRESSURE AREA DEPICTED BY THE MODELS WEAKENING AS IT DRIFTS NORTHWARD. THUS WILL PROVIDE LITTLE FORCING SO HAVE KEPT ONLY ISOLATED CONVECTION FOR THE OVERNIGHT PERIOD. FOR LOW TEMPERATURES ARE EXPECTED TO FALL INTO THE LOWER TO MIDDLE 70S. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...A WARM AND MOIST AIRMASS WILL REMAIN IN PLACE OVER THE EASTERN CAROLINAS IN ADVANCE OF A SLOW-MOVING COLD FRONT...WHICH WILL BE POSITIONED TO THE NW OVER THE APPALACHIANS BY THE END OF THE SHORT TERM. THIS FRONT WILL BE PRECEDED BY A PRE-FRONTAL TROUGH...WHILE AT THE MID LEVELS AN H/5 TROUGH DEEPENS OVER EASTERN CONUS. AMPLE MOISTURE AND A SERIES OF UPPER DISTURBANCES ROUNDING THE BASE OF THE H/5 TROUGH MEANS CHANCE POPS WILL REMAIN IN PLAY FOR BOTH THURSDAY AND FRIDAY. BEST CHANCES FOR CONVECTION WILL ACTUALLY BE ON FRIDAY...WHEN GUIDANCE SUGGESTS WE WILL HAVE THE DEEPEST MOISTURE AND WHEN THE PREFRONTAL TROUGH IMPINGES UPON THE CWA. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 3 PM WEDNESDAY...LOOKS LIKE UNSETTLED WEATHER WILL EXIST THROUGH MUCH OF THE WEEKEND AS LINGERING FRONT/LOW PRESSURE TROUGH REMAINS OVER INLAND CAROLINAS THROUGH SATURDAY INTO EARLY SUNDAY. WINDS WILL BASICALLY STAY SW THROUGH THE COLUMN SAT THROUGH SUNDAY MORNING WITH DEEP LAYER MOISTURE AND MINOR PERTURBATIONS RIDING AROUND THE DEEP LONG WAVE MID TO UPPER LEVEL DIGGING DOWN FROM THE GREAT LAKES TO THE GULF COAST. MAY SEE A DRY PUNCH THROUGH SATURDAY WITH A DROP IN PCP WATER VALUES DOWN TO LESS THAN 1.5 INCHES...MAINLY INLAND EARLIER IN THE DAY. PCP WATER VALUES UP NEAR 2 INCHES ALONG THE CAPE FEAR COAST WILL SEE SOME DRYING OUT BUT OVERALL EXPECT A MOIST AND UNSTABLE AIR MASS WITH INCREASED POTENTIAL FOR SHWRS AND TSTMS THROUGH SATURDAY INTO EARLY SUNDAY BEFORE NEXT COLD FRONT MOVES IN. ECMWF REMAINS SLIGHTLY DRIER AS POSITION OF UPPER TROUGH FARTHER EAST THROUGH SATURDAY BUT WILL HAVE TO SEE WHAT NEW MODEL RUN BRINGS. THIS MID TO UPPER TROUGH WILL PUSH A COLD FRONT EAST THROUGH THE CAROLINAS ON SUNDAY WITH PLENTY OF DRY AIR BEHIND IT. THIS RUSH OF DRY AND RELATIVELY COOLER AIR SHOULD MAKE ITS WAY IN THROUGH SUN AFTN AS PCP WATER VALUES DROP TO LESS THAN AN INCH WITH AN ADDITIONAL DROP DOWN TO LESS THAN A HALF INCH BY MON INTO TUES. 850 TEMPS SHOW A DROP FROM NEAR 17C SAT EVENING TO 11C BY MON MORNING. THEREFORE EXPECT TEMPS DOWN BELOW NORMAL...CLOSER TO 80 FOR HIGHS AND DEWPOINT TEMPS DOWN BELOW 50 IN SPOTS INLAND AND MID 50S MOST PLACES MON INTO TUES. THIS VERY DRY AIR IN PLACE WILL CREATE LARGER DIURNAL RANGES WITH LOW TEMPS TO DROP INTO THE 50S AND 60S ALONG THE COAST SUN NIGHT AND MON NIGHT. OVERALL EXPECT UNSETTLED WEATHER WITH PLENTY OF CLOUDS AND INCREASED POTENTIAL FOR SHWRS/TSTMS IN A MORE HUMID AIR MASS AHEAD OF COLD FRONT THROUGH EARLY SUNDAY. THEN MUCH LESS HUMID WEATHER WITH COOLER NIGHT AND WARMER EVE THROUGH TUES AS DRY HIGH PRESSURE DOMINATES OUR WEATHER. BY LATE NEXT WED WINDS WILL COME AROUND BECOMING MORE ON SHORE WITH A SLIGHT INCREASE IN MOISTURE BUT ANY PCP SHOULD HOLD OFF UNTIL WED NIGHT OR THURS. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...THE CONVERGENT BAND OF CONVECTION SPOOLING OFF OF A LOW IN GEORGIA HAS MOVED THROUGH THE CWA...HOWEVER THE ATMOSPHERE EXPECTED TO RELOAD WITH INSTABILITY BY TAF TIME. EXPECT THE RESULTANT BOUNDARY TO BE THE FOCUS FOR CONVECTION NEAR SHORE...WITH ISOLATED ACTIVITY INLAND. BRIEF IFR POSSIBLE...BUT MVFR IN SHOWERS FOR THE MOST PART. MOST OF THE ACTIVITY WILL DIMINISH BY LATE AFTERNOON. OVERNIGHT...SOME LIGHT FOG COMBINED WITH MVFR/NEAR IFR CEILINGS TOWARD MORNING WITH CONTINUED LOW LEVEL MOISTURE. COULD NOT RULE OUT A SHOWER BASED ON THE NAM...HOWEVER IT HAS BEEN OVERDOING IT THROUGH THE OVERNIGHT HOURS. THURSDAY...CONTINUED HOT AND HUMID WITH AFTERNOON CONVECTION POSSIBLE. SOUTHWEST GRADIENT WILL BE STRONGER THAN TODAY...BECOMING GUSTY IN THE AFTERNOON. EXTENDED OUTLOOK...POSSIBLE NUMEROUS STORMS FRIDAY AND SATURDAY. STORMS ENDING SUNDAY MORNING WITH COOLER CONDITIONS INTO MONDAY.&& && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM WEDNESDAY...SOUTH TO SOUTH-SOUTHWEST WINDS OF 10 TO 15 KTS WITH SEAS OF 2 TO 3 FEET ARE CURRENTLY OCCURRING OVER THE COASTAL WATERS. AS HIGH PRESSURE WEAKENS SLOWLY OVERNIGHT AND THE INFLUENCE OF A COLD FRONT WEST OF THE CAROLINAS WILL CAUSE THE WINDS TO BECOME MORE SOUTHWESTERLY OVERNIGHT. WINDS SPEEDS ARE FORECAST TO RUN AROUND 15 KNOT. SEAS WILL RUN AROUND 3 FEET WITH A FEW 4 FOOTS IN THE SOUTHEAST PORTIONS OF THE LITTLE RIVER TO CAPE FEAR MARINE ZONE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...WINDS WILL REMAIN SOUTHWESTERLY THROUGH THE PERIOD AS A COLD FRONT SLOWLY ADVANCES UPON THE WATERS. THE FRONT WILL NOT MAKE IT TO THE WATERS DURING THE NEAR TERM...BUT WE WILL LIKELY SEE A GRADUAL TIGHTENING OF THE GRADIENT...WHICH WILL INCREASE WINDS FROM A GENERAL 10 TO 15 KT RANGE TO AROUND 15 KTS OR SO BY FRIDAY NIGHT. SEAS WILL LIKEWISE INCREASE...WITH 3 TO 4 FT SEAS DEVELOPING FRIDAY/FRIDAY NIGHT. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 PM WEDNESDAY...DECENT SW FLOW THROUGH MUCH OF THE WEEKEND AS TROUGH OF LOW PRESSURE REMAINS JUST INLAND OF COAST. DECENT GRADIENT THROUGH SAT MORNING WITH SW WINDS UP TO 15 KTS WILL DIMINISH THROUGH LATE SATURDAY INTO SUNDAY AS WINDS BEGIN TO VEER AROUND AS COLD FRONT APPROACHES FROM THE WEST. LATEST WNA SHOWS WIND SHIFT TO W-NW BY LATE SUNDAY AS COLD FRONT CROSSES THE WATERS. PERSISTENT SW WINDS WILL PUSH SEAS UP TO 3 TO 5 FT THROUGH SAT AND THEN DIMINISHING WITH OFF SHORE FLOW THROUGH LATE SUNDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...REK NEAR TERM...DRH SHORT TERM...REK/MBB LONG TERM...RGZ AVIATION...DL MARINE...REK/RGZ/DRH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
138 PM EDT WED SEP 9 2015 .SYNOPSIS... SUMMER LIKE HEAT WILL BE IN PLACE TODAY WITH SCATTERED THUNDERSTORMS...MOST NUMEROUS ALONG THE COAST. CLOUDS AND RAIN CHANCES THEN INCREASE LATE IN THE WEEK WITH THE SLOW APPROACH OF A COLD FRONT. THIS BOUNDARY MAY NOT PUSH THROUGH UNTIL MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1 PM WEDNESDAY...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE BEHIND THIS MORNINGS SHORTWAVE. MOST OF THIS AFTERNOONS CONVECTION IS EAST OF A LINE FROM LUMBERTON TO MYRTLE BEACH TO GEORGETOWN. THE 15/16 HRRR CONTINUE TO SHOW CONVECTION WANING LATER THIS AFTERNOON AND ONLY ISOLATED CONVECTION AFTER SUNSET. OVERNIGHT IT IS VERY HARD TO DETECT A SIGNIFICANT SHORTWAVE AS WAS EARLY THOUGHT. THE LOW PRESSURE AREA IS DEPICTED BY THE MODELS OF WEAKENING AS IT DRIFTS NORTHWARD. THUS WILL LITTLE FORCING HAVE KEPT ONLY ISOLATED FOR THE OVERNIGHT PERIOD. FOR LOW TEMPERATURES AREA EXPECTED TO FALL INTO THE LOWER TO MIDDLE 70S. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... PREFRONTAL TROUGH MOVES INTO THE CAROLINAS AND STALLS ON THURSDAY. AHEAD OF THIS FEATURE THERE SHOULD BE AMPLE MOISTURE FOR AT LEAST SCATTERED CONVECTIVE COVERAGE. MID LEVEL FORCING IN THE FORM OF VORT MAXES COME LATE IN THE DAY AND AT NIGHT PREVENTING THE NORMAL DIURNAL DYING OFF OF RADAR COVERAGE EVEN THOUGH DEEP CONVECTION MAY BE HARDER TO COME BY DUE TO THE DECREASE IN INSTABILITY. THIS BOUNDARY WEAKENS AND MOVES OFFSHORE BY FRIDAY AND WAS PREVIOUSLY TO BE REPLACED BY A LEGITIMATE COLD FRONT. THIS FRONT NOW APPEARS SLOWER LEAVING NOT MUCH IN THE WAY OF SURFACE FEATURES IN PLACE LOCALLY. FURTHER COMPLICATING FRIDAY FORECAST IS THE DIFFERENCE IN TIMING AMONGST MODELS WITH RESPECT TO SOME MID LEVEL IMPULSES. IN THE END DID NOT MAKE MUCH CHANGE AND WILL ONCE AGAIN CARRY CHANCE POPS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY... IMPRESSIVELY DEEP UPPER TROUGH DRIVES COLD FRONT INTO THE COASTAL PLAIN ON SATURDAY. BEING ALIGNED WITH THE FLOW ALOFT IT WILL STALL ON SUNDAY. SATURDAY OFFERS THE DEEPEST MOISTURE AND WILL LIKELY PAN OUT BEING A VERY UNSETTLED DAY WITH PERHAPS NUMEROUS SHOWERS AND IF THE DIURNAL TIMING IS RIGHT STRONGER THUNDERSTORMS. MODELS AT SOME ODDS REGARDING THE DEPTH AND TILT OF THE UPPER WAVE AND UNTIL IT ENTERS THE UPPER AIR NETWORK ITS HARD TO SPECULATE WHICH IS CORRECT. ON SUNDAY THE DEEP MOISTURE GETS SHUNTED OFFSHORE BUT SOME LOW LEVEL MOISTURE ALONG THE BOUNDARY WILL STILL CALL FOR SOME LOW RAIN CHANCES MAINLY ALONG THE COAST. COOLER AND DRYER AIR NOW APPEARS TO ARRIVE FASTER AND SHOULD BE ADVECTING IN MODERATELY STRONGLY BY MONDAY. COOLER WEATHER WILL LAST INTO TUESDAY AS THE CENTER OF THE LARGE HIGH BUILDS TO OUR NORTH. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...THE CONVERGENT BAND OF CONVECTION SPOOLING OFF OF A LOW IN GEORGIA HAS MOVED THROUGH THE CWA...HOWEVER THE ATMOSPHERE EXPECTED TO RELOAD WITH INSTABILITY BY TAF TIME. EXPECT THE RESULTANT BOUNDARY TO BE THE FOCUS FOR CONVECTION NEAR SHORE...WITH ISOLATED ACTIVITY INLAND. BRIEF IFR POSSIBLE...BUT MVFR IN SHOWERS FOR THE MOST PART. MOST OF THE ACTIVITY WILL DIMINISH BY LATE AFTERNOON. OVERNIGHT...SOME LIGHT FOG COMBINED WITH MVFR/NEAR IFR CEILINGS TOWARD MORNING WITH CONTINUED LOW LEVEL MOISTURE. COULD NOT RULE OUT A SHOWER BASED ON THE NAM...HOWEVER IT HAS BEEN OVERDOING IT THROUGH THE OVERNIGHT HOURS. THURSDAY...CONTINUED HOT AND HUMID WITH AFTERNOON CONVECTION POSSIBLE. SOUTHWEST GRADIENT WILL BE STRONGER THAN TODAY...BECOMING GUSTY IN THE AFTERNOON. EXTENDED OUTLOOK...POSSIBLE NUMEROUS STORMS FRIDAY AND SATURDAY. STORMS ENDING SUNDAY MORNING WITH COOLER CONDITIONS INTO MONDAY.&& .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 PM WEDNESDAY...SOUTH TO SOUTH-SOUTHWEST WINDS OF 10 TO 15 KTS WITH SEAS OF 2 TO 3 FEET CURRENTLY ARE OCCURRING OVER THE COASTAL WATERS. HIGH PRESSURE WILL SLOWLY LESSEN ITS IMPACT BY THIS EVENING AS A COLD FRONT WELL TO THE WEST MOVES CLOSER TO THE CAROLINAS. WINDS ARE EXPECTED TO SHIFT MORE TO THE SOUTHWEST AND INCREASE TO 10 TO 15 KNOTS. SEAS WILL GRADUALLY INCREASE TO 3 FEET. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... A PREFRONTAL TROUGH WILL BOOST WIND AND SEAS ON THURSDAY. WE ARE NOT ANTICIPATING HEADLINES OR ADVISORIES, BUT ITS BEEN FAIRLY QUIET SO THURSDAY WILL BE MORE UNSETTLED THAN THE PAST FEW DAYS WITH THE ADVENT OF SOME 4 FT SEAS. ON FRIDAY THIS BOUNDARY MOVES OFFSHORE AND WEAKENS IF NOT DISSIPATE ALTOGETHER. THE 20KT GUSTINESS SHOULD DROP OUT OF THE FORECAST AS WILL ANY 4 FT WAVES. A COLD FRONT WILL ALSO BE APPROACHING FROM THE NW ON FRIDAY BUT IT NOW LOOKS SLOWER THAN PREVIOUSLY FORECAST. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY... WITH THE SLOWER ARRIVAL OF COLD FRONT ON SATURDAY THE AREA MAY STAY IN AN INCREASED GRADIENT PRE-FRONTAL FLOW REGIME. AS SUCH WIND SPEEDS MAY NEED TO BE RE-EVALUATED AND RAISED ESPECIALLY AS SOME HIGHER MID LEVEL WINDS MAY BE IMPINGING UPON THE AREA. THE UPPER WAVE DRIVING THIS SYSTEM IS FAR FROM BEING SAMPLED BY THE UPPER AIR NETWORK HOWEVER AND SO NO LARGE CHANGES WILL BE MADE AT THIS TIME. SHOULD THINGS KEEP SLOWING DOWN THEN A SW WIND WILL REMAIN ON SUNDAY AS THE BOUNDARY EITHER STALLS ALONG THE COAST OR PERHAPS JUST INLAND. EITHER WAY THE STRONGER GRADIENT WILL HAVE PUSHED FURTHER OFFSHORE AND THE POSSIBILITY OF HIGHER WINDS AND SEAS THAN THE CURRENT FORECAST ALONG WITH IT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DRH SHORT TERM...MBB LONG TERM...MBB AVIATION...DL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
658 PM EDT WED SEP 9 2015 .SYNOPSIS... A COLD FRONT OVER NORTHERN OHIO WILL CONTINUE TO MOVE SOUTHEAST AWAY FROM THE LOCAL AREA TONIGHT. THE FRONT IS EXPECTED TO EVENTUALLY STALL NEAR THE OHIO RIVER ON THURSDAY MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE REGION TOMORROW AND TOMORROW NIGHT. ANOTHER COLD FRONT WILL FOLLOW ON FRIDAY WITH A POTENT UPPER AIR DISTURBANCE EXPECTED TO IMPACT THE LOCAL AREA OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... SHOWERS HAVE DIMINISHED ACROSS MOST OF THE AREA EXCEPT A FEW SPRINKLES THAT MOVED INTO SOUTHERN HANCOCK COUNTY. MOST AREAS WILL BE DRY FOR THE REMAINDER OF THE NIGHT BUT LEFT A LOW 20-30 POP IN ACROSS THE SOUTHERN COUNTIES AS SOME SHORTWAVE ENERGY CONTINUES TO STREAM NORTHEAST. LOW LEVEL DRY AIR SHOULD WIN OUT ACROSS THE NORTHERN COUNTIES AND REMOVED ANY REMAINING CHANCE OF RAIN FROM THE FORECAST. LOW CLOUDS HAVE ALREADY SCATTERED OUT ACROSS NW OHIO SO ANY PRECIPITATION REACHING THE GROUND WILL BE VERY LIGHT AS IT FALLS OUT OF A MID-CLOUD DECK. PREVIOUS DISCUSSION... AS FEARED...LITTLE PRECIP HAS DEVELOPED THIS AFTERNOON. SOME SCATTERED SHOWERS REMAIN OVER THE EASTERN END OF THE AREA. MOST OF THE GUIDANCE INCLUDING THE LATEST RUC AND HRRR SHOW THE POSSIBILITY OF NEW DEVELOPMENT THROUGH EARLY EVENING FROM ABOUT I-71 EAST. THIS SEEM PLAUSIBLE GIVEN THE SHOWERS OVER INDIANA AND SW OHIO SO WILL KEEP A SMALL MENTION FOR A FEW HOURS. BY MIDNIGHT ALL BUT THE SE END OF THE AREA SHOULD BE DRY. THE SURFACE FRONT WILL EVENTUALLY STALL AND THE THREAT FOR SHOWERS ACROSS THE SE TIP OF THE AREA COULD PERSIST INTO THURSDAY MORNING. THE NEAREST CLEARING IS STILL BACK BY CHICAGO SO THAT WILL TAKE SOME TO REACH THE LOCAL AREA AS WELL. DO THINK THAT THAT ABOUT THE NW 1/3 TO 1/2 OF THE AREA WILL BECOME PARTLY CLOUDY BY MORNING. THIS WILL RESULT IN A DECENT TEMPERATURE GRADIENT ACROSS THE AREA WITH LOW 60S IN THE SE AND READINGS WELL DOWN INTO THE 50S IN THE NW. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/... JUST MINOR ADJUSTMENTS TO THE SHORT TERM TODAY AS THE PREVIOUS PACKAGE WAS ON THE RIGHT TRACK. THURSDAY AND THURSDAY NIGHT WILL BE DRY. ANOTHER COLD FRONT IS STILL ON TRACK FOR FRIDAY. VERY LITTLE IF ANY PRECIP IS EXPECTED BEFORE 12Z. WILL END UP GOING WITH A FEW HOURS OF LIKELY MOST AREAS. UNFORTUNATELY THE BEST WINDOW FOR PRECIP IN THE EAST WILL BE FRIDAY AFTERNOON AND EVENING. THERE WILL BE A DISTINCT AIRMASS CHANGE BEHIND THIS FRONT WITH THE UNSEASONABLY COOL AIR SETTLING OVER THE AREA OVER THE WEEKEND. AS A RESULT...INSTABILITY SHOWERS HELPED ALONG BY LAKE ERIE CAN BE EXPECTED BOTH SATURDAY AND SUNDAY. BY 12Z SUNDAY 500 MB TEMPS WILL BE ON THEIR WAY TO NEG 20 OR COLDER WHICH WILL GIVE LAKE TO 500MB TEMP DIFFERENCES OF 45 DEGREES OR GREATER. THIS MEANS THUNDER WILL BE A GOOD BET DOWNWIND OF THE LAKE AND HAVE BUMPED PRECIP CHANCES TO LIKELY IN FAR NE OH AND NW PA FOR SATURDAY NIGHT. HAVE CONTINUED THE RECENT TREND OF LOWERING HIGH TEMPS OVER THE WEEKEND. THERE COULD BE A FEW AREAS THAT FAIL TO GET OUT OF THE 50S FOR HIGHS ON SUNDAY. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AN UPPER LEVEL LOW WILL BE MOVING OFF TO THE EAST ON SUNDAY WILL BRING COLDER TEMPERATURES 10-15 DEGREES BELOW AVERAGE AND NORTHWESTERLY FLOW TO NORTHERN OHIO AND NORTHEAST PA. THIS NORTHWEST FLOW OFF OF LAKE ERIE...PLUS 850 MB TEMPERATURES OF 6-8C...AND WARM LAKE WATER TEMPERATURES AROUND 70F (A TEMPERATURE DIFFERENCE OF AROUND 25 DEGREES FAHRENHEIT) WILL ALLOW FOR SOME SIGNIFICANT LAKE EFFECT RAIN TO DEVELOP OVER THE AREA ON SUNDAY INTO THE EARLY PART OF MONDAY. IN SHORT...SUNDAY WILL BE MORE REPRESENTATIVE OF A COLD AND RAINY NOVEMBER DAY THAN THE GLIMPSE OF JULY THAT WE HAD OVER LABOR DAY WEEKEND. LATE ON MONDAY...SOME UPPER LEVEL RIDGING WILL MOVE IN ALONG WITH A SURFACE HIGH PRESSURE. WINDS WILL SHIFT TO COME FROM THE SOUTH AND WILL WARM TEMPERATURES CLOSER TO CLIMO AND DRY THE AREA OUT FROM WET WEATHER OVER THE WEEKEND. HIGH PRESSURE LOOKS TO BE IN PLACE THROUGH A MAJORITY OF WEDNESDAY ALLOWING FOR A COUPLE OF DRY...TYPICAL MID- SEPTEMBER DAYS IN NORTHERN OHIO AND NORTHWEST PA. MODELS CURRENTLY DEPICT A COLD FRONT BEGINNING TO APPROACH THE AREA BY THURSDAY MORNING...WHICH COULD BRING SOME WET WEATHER FOR THE END OF NEXT WEEK. STILL A LITTLE FAR OUT TO TELL WHAT COULD HAPPEN WITH THIS SYSTEM AS IT APPROACHES THE EASTERN GREAT LAKES. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... COLD FRONT IS NOW EAST OF THE TAF SITES WITH A FEW SCATTERED SHOWERS AND MAYBE A RUMBLE OF THUNDER LAGGING BEHIND. WIDESPREAD MVFR CONDITIONS WITH CEILINGS ON EITHER SIDE OF 2K FEET WILL BE COMMON THROUGH THE REMAINDER OF THE AFTERNOON. THE FRONTS EASTWARD PROGRESS SLOWS TONIGHT AND SHOWERS MAY CONTINUE ACROSS CAK/YNG INTO THE NIGHT. QUESTIONS WITH WHAT CEILINGS MAY DO OVERNIGHT. FORECAST SOUNDINGS AND OBSERVED SOUNDINGS SHOW THE LOWER LEVEL MOISTURE RESIDING BELOW MID LEVEL DRYING. GUIDANCE IS SUGGESTING VFR CONDITIONS OVERNIGHT...BUT WITH FRONT LINGERING TO OUR SOUTHEAST AND A NORTHEAST FLOW OFF OF THE LAKE...THINK AT LEAST KEEPING MVFR CEILINGS AROUND WOULD BE THE WAY TO GO. WINDS HAVE SHIFTED TO THE WEST- NORTHWEST TO NORTHWEST AND WILL CONTINUE TO ROTATE AROUND TO NORTHEAST THIS EVENING AND CONTINUE FROM THAT DIRECTION THURSDAY. OUTLOOK...NON VFR STARTING LATER FRIDAY AND CONTINUING THROUGH THE WEEKEND...ESPECIALLY FOR NE OH AND NW PA. && .MARINE... HAVE CANCELED THE SMALL CRAFT ADVISORY. LATEST GUIDANCE AND ANALYSIS OF CURRENT CONDITIONS LEADS TOWARD 2 TO OCCASIONALLY 4 FEET OVERNIGHT. THE GRADIENT IS NOT THAT TIGHT AND COLD AIR ADVECTION NOT STRONG. NORTH FLOW COMES AROUND TO THE NORTHEAST THIS EVENING AND WILL BE SITTING AT 10 TO 15 KNOTS SUSTAINED. HIGH PRESSURE WILL STAY NORTH OF THE LAKE ON THURSDAY AND GET SQUEEZED OUT BY AN APPROACHING COLD FRONT FROM THE NORTHWEST ON FRIDAY. THIS FRONT WILL HAVE THE POTENTIAL TO CHURN UP THE LAKE WITH STRONG COLD AIR ADVECTION COMMENCING FRIDAY NIGHT OR SATURDAY MORNING. SMALL CRAFT ADVISORIES A POSSIBILITY THIS WEEKEND. UPPER LOW STAYS IN THE VICINITY AND IT WILL BE A COOL AND SHOWERY WEEKEND. WINDS ARE NOT TOO STRONG ALOFT AND WATERSPOUTS MAY BE POSSIBLE THIS WEEKEND TOO. HIGH PRESSURE BUILDS ACROSS THE LOWER OHIO VALLEY MONDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...SEFCOVIC AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
345 PM EDT WED SEP 9 2015 .SYNOPSIS... A COLD FRONT OVER NORTHERN OHIO WILL CONTINUE TO MOVE SOUTHEAST AWAY FROM THE LOCAL AREA TONIGHT. THE FRONT IS EXPECTED TO EVENTUALLY STALL NEAR THE OHIO RIVER ON THURSDAY MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE REGION TOMORROW AND TOMORROW NIGHT. ANOTHER COLD FRONT WILL FOLLOW ON FRIDAY WITH A POTENT UPPER AIR DISTURBANCE EXPECTED TO IMPACT THE LOCAL AREA OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS FEARED...LITTLE PRECIP HAS DEVELOPED THIS AFTERNOON. SOME SCATTERED SHOWERS REMAIN OVER THE EASTERN END OF THE AREA. MOST OF THE GUIDANCE INCLUDING THE LATEST RUC AND HRRR SHOW THE POSSIBILITY OF NEW DEVELOPMENT THROUGH EARLY EVENING FROM ABOUT I-71 EAST. THIS SEEM PLAUSIBLE GIVEN THE SHOWERS OVER INDIANA AND SW OHIO SO WILL KEEP A SMALL MENTION FOR A FEW HOURS. BY MIDNIGHT ALL BUT THE SE END OF THE AREA SHOULD BE DRY. THE SURFACE FRONT WILL EVENTUALLY STALL AND THE THREAT FOR SHOWERS ACROSS THE SE TIP OF THE AREA COULD PERSIST INTO THURSDAY MORNING. THE NEAREST CLEARING IS STILL BACK BY CHICAGO SO THAT WILL TAKE SOME TO REACH THE LOCAL AREA AS WELL. DO THINK THAT THAT ABOUT THE NW 1/3 TO 1/2 OF THE AREA WILL BECOME PARTLY CLOUDY BY MORNING. THIS WILL RESULT IN A DECENT TEMPERATURE GRADIENT ACROSS THE AREA WITH LOW 60S IN THE SE AND READINGS WELL DOWN INTO THE 50S IN THE NW. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/... JUST MINOR ADJUSTMENTS TO THE SHORT TERM TODAY AS THE PREVIOUS PACKAGE WAS ON THE RIGHT TRACK. THURSDAY AND THURSDAY NIGHT WILL BE DRY. ANOTHER COLD FRONT IS STILL ON TRACK FOR FRIDAY. VERY LITTLE IF ANY PRECIP IS EXPECTED BEFORE 12Z. WILL END UP GOING WITH A FEW HOURS OF LIKELY MOST AREAS. UNFORTUNATELY THE BEST WINDOW FOR PRECIP IN THE EAST WILL BE FRIDAY AFTERNOON AND EVENING. THERE WILL BE A DISTINCT AIRMASS CHANGE BEHIND THIS FRONT WITH THE UNSEASONABLY COOL AIR SETTLING OVER THE AREA OVER THE WEEKEND. AS A RESULT...INSTABILITY SHOWERS HELPED ALONG BY LAKE ERIE CAN BE EXPECTED BOTH SATURDAY AND SUNDAY. BY 12Z SUNDAY 500 MB TEMPS WILL BE ON THEIR WAY TO NEG 20 OR COLDER WHICH WILL GIVE LAKE TO 500MB TEMP DIFFERENCES OF 45 DEGREES OR GREATER. THIS MEANS THUNDER WILL BE A GOOD BET DOWNWIND OF THE LAKE AND HAVE BUMPED PRECIP CHANCES TO LIKELY IN FAR NE OH AND NW PA FOR SATURDAY NIGHT. HAVE CONTINUED THE RECENT TREND OF LOWERING HIGH TEMPS OVER THE WEEKEND. THERE COULD BE A FEW AREAS THAT FAIL TO GET OUT OF THE 50S FOR HIGHS ON SUNDAY. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AN UPPER LEVEL LOW WILL BE MOVING OFF TO THE EAST ON SUNDAY WILL BRING COLDER TEMPERATURES 10-15 DEGREES BELOW AVERAGE AND NORTHWESTERLY FLOW TO NORTHERN OHIO AND NORTHEAST PA. THIS NORTHWEST FLOW OFF OF LAKE ERIE...PLUS 850 MB TEMPERATURES OF 6-8C...AND WARM LAKE WATER TEMPERATURES AROUND 70F (A TEMPERATURE DIFFERENCE OF AROUND 25 DEGREES FAHRENHEIT) WILL ALLOW FOR SOME SIGNIFICANT LAKE EFFECT RAIN TO DEVELOP OVER THE AREA ON SUNDAY INTO THE EARLY PART OF MONDAY. IN SHORT...SUNDAY WILL BE MORE REPRESENTATIVE OF A COLD AND RAINY NOVEMBER DAY THAN THE GLIMPSE OF JULY THAT WE HAD OVER LABOR DAY WEEKEND. LATE ON MONDAY...SOME UPPER LEVEL RIDGING WILL MOVE IN ALONG WITH A SURFACE HIGH PRESSURE. WINDS WILL SHIFT TO COME FROM THE SOUTH AND WILL WARM TEMPERATURES CLOSER TO CLIMO AND DRY THE AREA OUT FROM WET WEATHER OVER THE WEEKEND. HIGH PRESSURE LOOKS TO BE IN PLACE THROUGH A MAJORITY OF WEDNESDAY ALLOWING FOR A COUPLE OF DRY...TYPICAL MID- SEPTEMBER DAYS IN NORTHERN OHIO AND NORTHWEST PA. MODELS CURRENTLY DEPICT A COLD FRONT BEGINNING TO APPROACH THE AREA BY THURSDAY MORNING...WHICH COULD BRING SOME WET WEATHER FOR THE END OF NEXT WEEK. STILL A LITTLE FAR OUT TO TELL WHAT COULD HAPPEN WITH THIS SYSTEM AS IT APPROACHES THE EASTERN GREAT LAKES. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... COLD FRONT IS NOW EAST OF THE TAF SITES WITH A FEW SCATTERED SHOWERS AND MAYBE A RUMBLE OF THUNDER LAGGING BEHIND. WIDESPREAD MVFR CONDITIONS WITH CEILINGS ON EITHER SIDE OF 2K FEET WILL BE COMMON THROUGH THE REMAINDER OF THE AFTERNOON. THE FRONTS EASTWARD PROGRESS SLOWS TONIGHT AND SHOWERS MAY CONTINUE ACROSS CAK/YNG INTO THE NIGHT. QUESTIONS WITH WHAT CEILINGS MAY DO OVERNIGHT. FORECAST SOUNDINGS AND OBSERVED SOUNDINGS SHOW THE LOWER LEVEL MOISTURE RESIDING BELOW MID LEVEL DRYING. GUIDANCE IS SUGGESTING VFR CONDITIONS OVERNIGHT...BUT WITH FRONT LINGERING TO OUR SOUTHEAST AND A NORTHEAST FLOW OFF OF THE LAKE...THINK AT LEAST KEEPING MVFR CEILINGS AROUND WOULD BE THE WAY TO GO. WINDS HAVE SHIFTED TO THE WEST- NORTHWEST TO NORTHWEST AND WILL CONTINUE TO ROTATE AROUND TO NORTHEAST THIS EVENING AND CONTINUE FROM THAT DIRECTION THURSDAY. OUTLOOK...NON VFR STARTING LATER FRIDAY AND CONTINUING THROUGH THE WEEKEND...ESPECIALLY FOR NE OH AND NW PA. && .MARINE... HAVE CANCELED THE SMALL CRAFT ADVISORY. LATEST GUIDANCE AND ANALYSIS OF CURRENT CONDITIONS LEADS TOWARD 2 TO OCCASIONALLY 4 FEET OVERNIGHT. THE GRADIENT IS NOT THAT TIGHT AND COLD AIR ADVECTION NOT STRONG. NORTH FLOW COMES AROUND TO THE NORTHEAST THIS EVENING AND WILL BE SITTING AT 10 TO 15 KNOTS SUSTAINED. HIGH PRESSURE WILL STAY NORTH OF THE LAKE ON THURSDAY AND GET SQUEEZED OUT BY AN APPROACHING COLD FRONT FROM THE NORTHWEST ON FRIDAY. THIS FRONT WILL HAVE THE POTENTIAL TO CHURN UP THE LAKE WITH STRONG COLD AIR ADVECTION COMMENCING FRIDAY NIGHT OR SATURDAY MORNING. SMALL CRAFT ADVISORIES A POSSIBILITY THIS WEEKEND. UPPER LOW STAYS IN THE VICINITY AND IT WILL BE A COOL AND SHOWERY WEEKEND. WINDS ARE NOT TOO STRONG ALOFT AND WATERSPOUTS MAY BE POSSIBLE THIS WEEKEND TOO. HIGH PRESSURE BUILDS ACROSS THE LOWER OHIO VALLEY MONDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...SEFCOVIC AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1226 PM CDT WED SEP 9 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...VFR CONDITIONS. SEA BREEZE NOT QUITE ESTABLISHED YET...AND MAY HAVE A TOUGH TIME WITH BREEZY SOUTH SOUTHEAST WINDS IN CONTROL. FEW TO SCT LOW CLOUDS MAINLY EAST OF US281/IH69C. MOSTLY CLEAR SKIES TONIGHT. DEEPER MOISTURE WILL BRING THICKER CLOUDS ON THURSDAY...BUT STILL LOOKING FOR VFR CONDITIONS. A WEAK SEA BREEZE WILL BE POSSIBLE. && .PREV DISCUSSION... /ISSUED 652 AM CDT WED SEP 9 2015/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS PREVAIL OVER DEEP SOUTH TEXAS THIS MORNING. VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS...EXCEPT A BRIEF PERIOD OF MVFR CONDITIONS POSSIBLE IN ANY CONVECTION. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. LIGHT SOUTHEAST WINDS WILL BECOME MODERATE LATER THIS MORNING WITH GUSTS AROUND 20 KNOTS IN THE AFTERNOON. WINDS WILL GRADUALLY WEAKEN THIS EVENING AND OVERNIGHT. PREV DISCUSSION... /ISSUED 434 AM CDT WED SEP 9 2015/ SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR SATELLITE IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN MEXICO AND A 500MB LOW OVER THE WESTERN GULF OF MEXICO. BROWNSVILLE RADAR SHOWS VERY ISOLATED ACTIVITY ACROSS THE LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS CONVECTION WILL INCREASE ACROSS THE GULF WATERS LATER THIS MORNING. BRO SOUNDING FROM TUESDAY EVENING INDICATES PRECIPITABLE WATER VALUES OF 2.02 INCHES. MOSTLY CLEAR SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS MORNING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS. THE COMBINATION OF THE 500MB LOW ACROSS THE WESTERN GULF OF MEXICO AND A FRONT MOVING SOUTH OVER CENTRAL TEXAS WILL ALLOW LOW TO MID LEVEL MOISTURE TO INCREASE ACROSS DEEP SOUTH TEXAS THROUGH THE FORECAST PERIOD. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. THE LATEST HRRR/GFS AND ECMWF SUGGEST AN ACTIVE SEA BREEZE TODAY WHILE THE MET REMAINS GENERALLY DRY. WILL LEAN TOWARDS THE WETTER MAV/ECMWF MOS POPS FOR TODAY. DEEPER MOISTURE SHOULD SUPPORT MORE ACTIVITY ACROSS THE AREA ON THURSDAY...ESPECIALLY ACROSS THE COASTAL WATERS AND THE RANCHLANDS. WILL BLEND TOWARDS THE WETTER NAM/ECMWF FOR POPS AREA WIDE FOR THURSDAY. ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY AND THURSDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY THOSE WITH A HISTORY OF FLOODING. HIGH TEMPERATURES TODAY WILL RANGE FROM THE LOWER 90S NEAR THE COAST TO AROUND 100 ACROSS THE UPPER VALLEY. HIGH TEMPERATURES WILL BE A FEW DEGREES LOWER ON THURSDAY DUE TO THE INCREASE IN CLOUDS AND RAIN CHANCES. LOW TEMPERATURES TONIGHT WILL GENERALLY BE IN THE UPPER 70S TO AROUND 80. LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...RATHER BUSY LONG TERM PORTION OF THE FORECAST ANTICIPATED. DEEP TROPICAL MOISTURE (PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES) WILL COMBINE WITH THE FRIDAY NIGHT PASSAGE OF A WEAK COLD FRONT...AND THE SUBSEQUENT DEVELOPMENT AND PERSISTENCE OF AN INVERTED SURFACE TROUGH OF LOW PRESSURE ALONG THE LOWER TEXAS COAST AFTERWARDS. WITH PERSISTENT 500 MB TROUGHINESS ALONG THE TEXAS COASTLINE IN ASSOCIATION WITH A CLOSED 500 MB LOW PRESSURE SYSTEM OVER THE GREAT LAKES REGION...DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY CAN EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FOR MUCH OF THE FORECAST PERIOD...WITH THE HIGHEST RAIN CHANCES FROM FRIDAY THROUGH SATURDAY...WHEN LOCALLY HEAVY RAINFALL HAS ALSO BEEN INCLUDED IN THE FORECAST. THE MOST INTERESTING ASPECT OF THE LONG TERM FORECAST PERIOD IS THE GFS` INDICATION THAT A WEAK CLOSED AREA OF LOW PRESSURE WILL FORM OVER THE WESTERN GULF OF MEXICO AND MOVE INLAND OVER THE BRO CWFA TOWARDS THE END OF THE FORECAST PERIOD. ANY CLOSED AREA OF LOW PRESSURE...SHOULD IT FORM...WOULD HAVE THE ABILITY TO RADICALLY CHANGE PRECIPITATION AND WIND VALUES ON MONDAY AND TUESDAY...AND THIS WILL NEED TO BE MONITORED BY SUCCESSIVE SHIFTS THROUGH THE NEXT FEW DAYS. MARINE...NOW THROUGH THURSDAY...BUOY DATA AND OBSERVATION PLATFORMS ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN 8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A WEAK PRESSURE GRADIENT OVER THE WESTERN GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND LOW TO MODERATE SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS. THURSDAY NIGHT THROUGH TUESDAY...GENERALLY LIGHT TO MODERATE WINDS AND LOW TO MODERATE SEAS ARE EXPECTED THROUGH THE PERIOD AS WEAK LOW PRESSURE PERSISTS OVER THE WESTERN GULF OF MEXICO AND A COLD FRONT INTRUDES INTO THE LOWER TEXAS COASTAL WATERS. WEAK CLOSED LOW PRESSURE MAY DEVELOP ALONG THE LOWER TEXAS COAST TOWARDS THE END OF THE FORECAST PERIOD PER ONE WEATHER FORECAST MODEL...BUT THE STRONGER WINDS AND HIGHER SEAS INDICATED IN ASSOCIATION WITH THE LOW PRESSURE DEVELOPMENT HAVE NOT BEEN INCLUDED IN THE FORECAST AT THIS TIME. BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 54/64
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
208 PM CDT WED SEP 9 2015 .SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT) ISSUED AT 208 PM CDT WED SEP 9 2015 BIG PICTURE WATER VAPOR IMAGERY/RAP ANALYSIS SHOWING A CLOSED UPPER LOW OVER WESTERN ONTARIO WITH A BROAD TROUGH OVER THE NORTHER/CENTRAL CONUS. AN EMBEDDED MID-LEVEL SHORTWAVE TROUGH WAS PUSHING INTO MN/DAKOTAS. RADAR MOSAIC SHOWING SCATTERED BAND OF SHOWERS AND THUNDERSTORMS AHEAD OF THIS WAVE EXTENDING FROM NORTHWEST WI/EAST CENTRAL MN TO SOUTH CENTRAL MN...MOVING EAST AT 35- 40KT. OTHERWISE...TEMPERATURES AS OF 2 PM RANGED FROM NEAR 70 ACROSS NORTH CENTRAL WI...TO THE 75-80 DEGREE RANGE ALONG AND SOUTH OF I-90. FOR THIS EVENING OVERNIGHT...WILL BE WATCHING THE WAVE CONTINUE MOVING EAST ACROSS OUR AREA. RAP DEPICTING INCREASING 850-700MB MOISTURE TRANSPORT ALONG WITH INCREASING MUCAPE...HIGHER 500-1000 J/KG SOUTH OF I-90. THEREFORE CARRIED SHRA/TS ALONG AND SOUTH OF I- 90 WITH ISOLATED THUNDER NORTH. MOST MESO MODELS DEPICTING SCATTERED NATURE TO THIS CONVECTION...SO MAINTAINED 30-50 POPS FOR NOW. ANOTHER STRONGER MID-LEVEL WAVE/DECENT 500-300MB PV-ADVECTION PUSHES IN ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY BY TOMORROW MORNING AND IS EXPECTED TO REINFORCE SHOWER/THUNDER CHANCES ACROSS THE AREA. WITH EXPECTED SCATTERED CONVECTION AND CLOUD COVER...WILL SEE COOLER TEMPERATURES WITH HIGHS ACROSS NORTH CENTRAL WI ONLY IN THE 65-70 DEGREE RANGE AND LOW-MID 70S SOUTH OF I-90. LOOKS LIKE SHOWER/ISOLATED THUNDER CHANCES PUSH OUT OF THE AREA BY LATER THURSDAY EVENING WITH CLEARING SKIES THROUGH THE OVERNIGHT HOURS. WITH DEEPENING MID/UPPER LEVEL TROUGH OVERHEAD AND RATHER COLD 850MB TEMPS DROPPING INTO THE 1-5C RANGE...WILL SEE OVERNIGHT LOWS DIP INTO THE 40S MOST LOCATIONS. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 208 PM CDT WED SEP 9 2015 FOR FRIDAY THROUGH SATURDAY NIGHT... ANOTHER EMBEDDED SHORTWAVE TROUGH COMES DOWN ACROSS THE AREA ON FRIDAY. STEEP LOW TO MID-LEVEL LAPSE RATES EXPECTED TO GENERATE QUITE A BIT OF CUMULUS AND SCATTERED SHOWERS...MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER. OTHERWISE...A RATHER CHILLY AUTUMN-LIKE DAY ON TAP AS HIGHS ONLY TOP OFF IN THE UPPER 50S TO THE MIDDLE 60S. CHILLY DAY FRIDAY AND CLEARING SKIES FRIDAY NIGHT AS SURFACE HIGHS SETTLES IN WILL SET THE STAGE FOR COLD TEMPERATURES FRIDAY NIGHT WITH LOWS DIPPING INTO TO THE UPPER 30S/AROUND 40 ACROSS NORTH CENTRAL WI...TO THE LOWER/MIDDLE 40S ELSEWHERE. MODELS SHOW THE MID-LEVEL TROUGH PUSHING INTO THE EASTERN GREAT LAKES/OHIO RIVER VALLEY SATURDAY AS MID-LEVEL RIDGE BUILD INTO OUR REGION. THIS WILL PROVIDE DRY AND SLIGHTLY WARMER //BUT STILL WELL BELOW NORMAL// TEMPERATURES IN THE LOW-MID 60S UNDER MOSTLY SUNNY SKIES. PLAN ON ANOTHER CLEAR AND COLD SATURDAY NIGHT WITH SURFACE HIGH OVERHEAD. LOOKS TO BE AN IDEAL RIVER VALLEY/BOG AREA FOG NIGHT WITH OVERNIGHT LOWS DIPPING INTO THE 40S ONCE AGAIN. DID NOT INCLUDE IN THE WEATHER GRIDS FOR NOW AS EXACT RIDGE LOCATION COULD CHANGE A BIT...BUT SOMETHING TO KEEP AN EYE ON NONETHELESS. FOR SUNDAY THROUGH WEDNESDAY...DAYS 4 TO 7... GFS AND ECMWF IN AGREEMENT ON A WARMING TREND FOR THIS PERIOD AS LOW PRESSURE LIFT ACROSS THE NORTHERN PLAINS INTO CANADA. THIS PUTS US IN WARM SECTOR WITH BROAD-SCALE LIFT ACROSS OUR AREA FOR A CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY IN THE TUESDAY NIGHT THROUGH WEDNESDAY TIME FRAME. LOOKS LIKE HIGHS ON SUNDAY IN THE 65-70 DEGREE RANGE...WARMING BACK INTO THE 70S...OR NEAR SEASONAL NORMALS...BY WEDNESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1230 PM CDT WED SEP 9 2015 MAIN TAF CONCERNS ARE SHOWERS/THUNDERSTORM CHANCES AT BOTH RST/LSE TAF SITES THIS EVENING INTO THURSDAY MORNING. A WEAK UPPER LEVEL DISTURBANCE OVER WESTERN MINNESOTA WILL MOVE OVER THE RST/LSE TAF SITES LATE THIS AFTERNOON INTO THURSDAY MORNING. THE LATEST 09.12Z RAP/NAM SUGGEST WEAK MOISTURE CONVERGENCE AND VERTICAL MOTION IN ASSOCIATION WITH THE UPPER LEVEL DISTURBANCE. DRY AIR ALOFT AND NEAR THE SURFACE WILL ALLOW CLOUD HEIGHTS TO REMAIN ABOVE THE MVFR CONDITIONS FOR THE MAJORITY OF THE TAF PERIOD. WITH THE FAST PROGRESSION OF THE UPPER LEVEL DISTURBANCE...CEILING HEIGHTS MAY BRIEFLY LOWER TO MVFR BETWEEN THE 03Z-10Z THURSDAY TIME FRAME. EXPECT VFR CONDITIONS TO PREVAIL AT BOTH TAF SITES THROUGH TAF PERIOD. THUNDERSTORM PROBABILITIES REMAIN VERY LOW AT TAF SITES...AS THE 09.12Z NAM/RAP SUGGEST LIMITED ELEVATED INSTABILITY WITH THE UPPER LEVEL DISTURBANCE. WILL KEEP MENTION OF THUNDER OUT OF TAF PERIOD...DUE TO THIS LIMITED INSTABILITY AND ISOLATED TO SCATTERED COVERAGE OF CONVECTION. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...DTJ