Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/22/13


AREA FORECAST DISCUSSION
NWS PHOENIX AZ
840 AM MST SAT JUL 20 2013 .SYNOPSIS... A VERY MOIST AIRMASS IS EXPECTED TO REMAIN OVER THE REGION AS A LOW PRESSURE SYSTEM IN MEXICO MOVES OFF WELL TO SOUTH AND WEST. ABOVE NORMAL RAIN CHANCES AND BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH MONDAY. SOMEWHAT DRIER AND WARMER WEATHER IS EXPECTED FROM TUESDAY ONWARD THROUGH THE END OF NEXT WEEK AS HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE ROCKIES. && .DISCUSSION... AFTER A RATHER ACTIVE NIGHT...WITH WIDESPREAD RAINFALL BEING REPORTED FROM AN MCS THAT MOVED FROM THE NORTHERN AND WESTERN PORTION OF THE PHOENIX AREA ACROSS SOUTHWEST ARIZONA...AND INTO THE LOWER COLORADO RIVER VALLEY...THINGS HAVE QUIETED DOWN CONSIDERABLY ACROSS THE REGION THIS MORNING. THE MCS THAT BROUGHT ALL THE RAINFALL EARLIER THIS MORNING HAS WEAKENED TO JUST A FEW SHOWERS ACROSS WESTERN AZ AND THE LOWER COLORADO RIVER VALLEY. THE MAIN IMPACT FROM THE RAINFALL AND CLOUDINESS IS TO COOL TEMPERATURES ACROSS MUCH OF THE REGION...WITH MANY LOCATIONS ACROSS THE LOWER DESERTS OF WESTERN AZ AND THE LOWER COLORADO RIVER VALLEY NOW SEEING TEMPERATURES IN THE 70S. THIS RAIN-COOLED AIR AND DEBRIS CLOUDS WILL LIKE DELAY THE ONSET OF CONVECTIVE ACTIVITY TODAY...WITH THE LATEST MODEL RUNS SHOWING SHOWER AND THUNDERSTORM DEVELOPMENT HOLDING OFF UNTIL THIS EVENING AND TONIGHT. OTHER THAN SOME ADJUSTMENTS TO LOWER TEMPERATURES ACROSS SOUTHWEST AZ AND SOUTHEAST CA...CURRENT GRIDDED FORECAST ARE HOLING UP QUITE WELL. && .PREVIOUS DISCUSSION... UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL GULF OF CALIFORNIA THIS MORNING. EXTENDING NORTHWARD FROM THE LOW INTO CENTRAL AZ IS AN INVERTED TROUGH AND MCV...WHICH HAVE HELPED TO SUSTAIN A NOCTURNAL MCS ACROSS THE LOWER DESERTS OF AZ. LATEST IR IMAGERY INDICATES THAT CLOUD TOPS HAVE COOLED TO AS LOW AS -75C...WHICH CORRELATES TO TOPS AROUND 40-45K FT...THOUGH KIWA RADAR SUGGESTS SOME OVERSHOOTING TOPS MAY BE AS HIGH AS 55K FT. MUCH OF PHOENIX...NORTH SCOTTSDALE AND THE WEST VALLEY RECEIVED MEASURABLE RAINFALL OVER THE PAST 6 HOURS...WITH SOME SPOTS MEASURING ALMOST AN INCH. WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY CONTINUES AT THIS HOUR FROM MARICOPA COUNTY WESTWARD...INCLUDING LA PAZ...YUMA AND RIVERSIDE COUNTIES. IT IS EXPECTED THAT CONVECTION WILL CONTINUE TO DEVELOP EARLY THIS MORNING ALONG OUTFLOW BOUNDARIES PROPAGATING INTO THE MOISTURE-RICH ENVIRONMENT OF SW AZ AND SE CA. HEAVY RAINFALL AND MINOR FLOODING ARE THE MAIN THREATS WITH THESE STORMS. GLOBAL MODELS NOTORIOUSLY HAVE A DIFFICULT TIME INITIALIZING PROPERLY WHEN THERE IS CONVECTION OVERNIGHT. FORECAST IS INSTEAD WEIGHTED MORE TOWARDS THE HI-RES CONVECTIVE ALLOWING MODELS SUCH AS THE WRF-NMM FOR SPC...WHICH HAS PICKED UP ON THE CURRENT ACTIVITY. ALTHOUGH THE EASTERLY FLOW BETWEEN THE LOW TO THE SOUTH AND THE ANTICYCLONE ACROSS NV WILL DIMINISH TODAY...SOUTH-CENTRAL AZ IS AGAIN FAVORED FOR NOCTURNAL CONVECTION. CONDITIONS REMAIN SO ANOMALOUSLY MOIST THAT MODELS SUCH AS THE HRRR SUGGEST THAT CONVECTION MAY INITIATE AS EARLY AS THIS AFTERNOON. TEMPERATURES WILL ALSO BE CONSIDERABLY LOWER TODAY...WITH HIGH TEMPERATURES STRUGGLING TO REACH THE 100 DEGREE MARK IN THE LOWER DESERTS. THE UPPER LOW ACROSS THE GOC IS EXPECTED TO LIFT NORTHWARD TO A POSITION JUST WEST OF ROCKY POINT SUNDAY. THE THREAT OF SHOWERS AND THUNDERSTORMS WILL PERSIST JUST ABOUT EVERYWHERE ACROSS THE FORECAST AREA. POPS IN THE 12Z-18Z PERIOD SUNDAY WERE INCREASED...OWING TO MUCH HIGHER PROBABILITIES FROM THE NMM-BASED GUIDANCE SUCH AS THE SREF. WITH THE AMPLE MOISTURE AND SUBSEQUENT CLOUDINESS...AN ADDITIONAL 3 TO 5 DEGREES OF COOLING IS ALSO ANTICIPATED. EARLY NEXT WEEK...THE UPPER LOW WILL GET PICKED UP BY THE WESTERLIES AS THE ANTICYCLONE SLIDES TOWARDS THE FOUR CORNERS. THE RESULTING SOUTHWESTERLY FLOW WILL ADVECT DRIER AIR INITIALLY INTO SE CA AND SW AZ...WHICH WILL CONFINE THE HIGHEST POPS TO HIGHER TERRAIN NORTH AND EAST OF PHOENIX. THE RIDGE WILL BECOME REESTABLISHED ACROSS THE SOUTHERN PLAINS THURSDAY...WHICH WILL ALLOW ANOTHER MOIST INVERTED TROUGH TO APPROACH SOUTHERN AZ. CONSEQUENTLY...A RETURN TO NEAR CLIMO POPS/TEMPS IS FORECAST FOR THE END OF THE WEEK. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL... NEW STORMS CONTINUE TO DEVELOP OVER HIGHER TERRAIN EAST OF GLOBE. ALTHOUGH SLOW TO MOVE WEST...MAY SEE EASTERLY OUTFLOW FROM THESE STORMS AFFECTING KIWA LATER AFTER 11Z. OUTSIDE OF THIS ACTIVITY... LIGHT WINDS AND SCT-BKN CLOUD DECKS GENERALLY AOA 10KFT ARE EXPECTED ACROSS THE SOUTH-CENTRAL AZ DESERTS THIS MORNING. BY 20Z...STORMS WILL AGAIN FORM OVER THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH... SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER SOUTHEAST CALIFORNIA THIS MORNING THROUGH AT LEAST 13Z...WITH GUSTY OUTFLOWS UP TO 30KT POSSIBLE AT TIMES. SCT-BKN CLOUD DECKS GENERALLY AOA 10KFT WITH LOCAL CIGS DOWN TO 8KFT IN HEAVIER SHOWERS AND THUNDERSTORMS...SKIES IMPROVING LATER THIS MORNING. WINDS SOUTHERLY 10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE LOWER COLORADO RIVER VALLEY WITH LIGHTER SOUTHEASTERLY WINDS AT KIPL. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... MONDAY THROUGH FRIDAY... ABOVE NORMAL PRECIP CHANCES WILL REMAIN A POSSIBILITY ON MONDAY AS A AN AREA OF LOW PRESSURE EXISTS THE AREA. A SWITCH TO A SOUTHERLY FLOW ALOFT WILL LIKELY BRING DRYING CONDITIONS AND ENDING PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA FOR THE MIDDLE OF NEXT WEEK. HUMIDITIES WILL REMAIN ELEVATED THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY. STORM COVERAGE AND INTENSITY WILL VARY FROM DAY TO DAY WHICH WILL IMPACT FORECAST WINDS...POTENTIALLY DISRUPTING NORMAL DIURNAL PATTERNS. $$ && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...PERCHA/HIRSCH AVIATION...MEYERS FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
330 AM MST SAT JUL 20 2013 .SYNOPSIS... A VERY MOIST AIRMASS IS EXPECTED TO REMAIN OVER THE REGION AS A LOW PRESSURE SYSTEM IN MEXICO MOVES OFF WELL TO SOUTH AND WEST. ABOVE NORMAL RAIN CHANCES AND BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH MONDAY. SOMEWHAT DRIER AND WARMER WEATHER IS EXPECTED FROM TUESDAY ONWARD THROUGH THE END OF NEXT WEEK AS HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE ROCKIES. && .DISCUSSION... UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL GULF OF CALIFORNIA THIS MORNING. EXTENDING NORTHWARD FROM THE LOW INTO CENTRAL AZ IS AN INVERTED TROUGH AND MCV...WHICH HAVE HELPED TO SUSTAIN A NOCTURNAL MCS ACROSS THE LOWER DESERTS OF AZ. LATEST IR IMAGERY INDICATES THAT CLOUD TOPS HAVE COOLED TO AS LOW AS -75C...WHICH CORRELATES TO TOPS AROUND 40-45K FT...THOUGH KIWA RADAR SUGGESTS SOME OVERSHOOTING TOPS MAY BE AS HIGH AS 55K FT. MUCH OF PHOENIX...NORTH SCOTTSDALE AND THE WEST VALLEY RECEIVED MEASURABLE RAINFALL OVER THE PAST 6 HOURS...WITH SOME SPOTS MEASURING ALMOST AN INCH. WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY CONTINUES AT THIS HOUR FROM MARICOPA COUNTY WESTWARD...INCLUDING LA PAZ...YUMA AND RIVERSIDE COUNTIES. IT IS EXPECTED THAT CONVECTION WILL CONTINUE TO DEVELOP EARLY THIS MORNING ALONG OUTFLOW BOUNDARIES PROPAGATING INTO THE MOISTURE-RICH ENVIRONMENT OF SW AZ AND SE CA. HEAVY RAINFALL AND MINOR FLOODING ARE THE MAIN THREATS WITH THESE STORMS. GLOBAL MODELS NOTORIOUSLY HAVE A DIFFICULT TIME INITIALIZING PROPERLY WHEN THERE IS CONVECTION OVERNIGHT. FORECAST IS INSTEAD WEIGHTED MORE TOWARDS THE HI-RES CONVECTIVE ALLOWING MODELS SUCH AS THE WRF-NMM FOR SPC...WHICH HAS PICKED UP ON THE CURRENT ACTIVITY. ALTHOUGH THE EASTERLY FLOW BETWEEN THE LOW TO THE SOUTH AND THE ANTICYCLONE ACROSS NV WILL DIMINISH TODAY...SOUTH-CENTRAL AZ IS AGAIN FAVORED FOR NOCTURNAL CONVECTION. CONDITIONS REMAIN SO ANOMALOUSLY MOIST THAT MODELS SUCH AS THE HRRR SUGGEST THAT CONVECTION MAY INITIATE AS EARLY AS THIS AFTERNOON. TEMPERATURES WILL ALSO BE CONSIDERABLY LOWER TODAY...WITH HIGH TEMPERATURES STRUGGLING TO REACH THE 100 DEGREE MARK IN THE LOWER DESERTS. THE UPPER LOW ACROSS THE GOC IS EXPECTED TO LIFT NORTHWARD TO A POSITION JUST WEST OF ROCKY POINT SUNDAY. THE THREAT OF SHOWERS AND THUNDERSTORMS WILL PERSIST JUST ABOUT EVERYWHERE ACROSS THE FORECAST AREA. POPS IN THE 12Z-18Z PERIOD SUNDAY WERE INCREASED...OWING TO MUCH HIGHER PROBABILITIES FROM THE NMM-BASED GUIDANCE SUCH AS THE SREF. WITH THE AMPLE MOISTURE AND SUBSEQUENT CLOUDINESS...AN ADDITIONAL 3 TO 5 DEGREES OF COOLING IS ALSO ANTICIPATED. EARLY NEXT WEEK...THE UPPER LOW WILL GET PICKED UP BY THE WESTERLIES AS THE ANTICYCLONE SLIDES TOWARDS THE FOUR CORNERS. THE RESULTING SOUTHWESTERLY FLOW WILL ADVECT DRIER AIR INITIALLY INTO SE CA AND SW AZ...WHICH WILL CONFINE THE HIGHEST POPS TO HIGHER TERRAIN NORTH AND EAST OF PHOENIX. THE RIDGE WILL BECOME REESTABLISHED ACROSS THE SOUTHERN PLAINS THURSDAY...WHICH WILL ALLOW ANOTHER MOIST INVERTED TROUGH TO APPROACH SOUTHERN AZ. CONSEQUENTLY...A RETURN TO NEAR CLIMO POPS/TEMPS IS FORECAST FOR THE END OF THE WEEK. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL... NEW STORMS CONTINUE TO DEVELOP OVER HIGHER TERRAIN EAST OF GLOBE. ALTHOUGH SLOW TO MOVE WEST...MAY SEE EASTERLY OUTFLOW FROM THESE STORMS AFFECTING KIWA LATER AFTER 11Z. OUTSIDE OF THIS ACTIVITY... LIGHT WINDS AND SCT-BKN CLOUD DECKS GENERALLY AOA 10KFT ARE EXPECTED ACROSS THE SOUTH-CENTRAL AZ DESERTS THIS MORNING. BY 20Z...STORMS WILL AGAIN FORM OVER THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH... SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER SOUTHEAST CALIFORNIA THIS MORNING THROUGH AT LEAST 13Z...WITH GUSTY OUTFLOWS UP TO 30KT POSSIBLE AT TIMES. SCT-BKN CLOUD DECKS GENERALLY AOA 10KFT WITH LOCAL CIGS DOWN TO 8KFT IN HEAVIER SHOWERS AND THUNDERSTORMS...SKIES IMPROVING LATER THIS MORNING. WINDS SOUTHERLY 10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE LOWER COLORADO RIVER VALLEY WITH LIGHTER SOUTHEASTERLY WINDS AT KIPL. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... MONDAY THROUGH FRIDAY... ABOVE NORMAL PRECIP CHANCES WILL REMAIN A POSSIBILITY ON MONDAY AS A AN AREA OF LOW PRESSURE EXISTS THE AREA. A SWITCH TO A SOUTHERLY FLOW ALOFT WILL LIKELY BRING DRYING CONDITIONS AND ENDING PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA FOR THE MIDDLE OF NEXT WEEK. HUMIDITIES WILL REMAIN ELEVATED THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY. STORM COVERAGE AND INTENSITY WILL VARY FROM DAY TO DAY WHICH WILL IMPACT FORECAST WINDS...POTENTIALLY DISRUPTING NORMAL DIURNAL PATTERNS. $$ && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...HIRSCH AVIATION...MEYERS FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
905 PM MST FRI JUL 19 2013 .SYNOPSIS...LOW PRESSURE OVER THE GULF OF CALIFORNIA WILL PROVIDE A MOIST EAST TO SOUTHEAST FLOW THIS WEEKEND. THIS FLOW WILL INCREASE CHANCES FOR SHOWERS AND THUNDERSTORMS WITH POTENTIALLY HEAVY RAINFALL. THEREAFTER...A MORE NORMAL CYCLE OF SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL RETURN FOR MUCH OF NEXT WEEK. && .DISCUSSION...ISOLATED SHOWERS ONGOING ACROSS ERN SANTA CRUZ AND SWRN COCHISE COUNTIES SOUTH OF TUCSON AS WELL AS ACROSS NRN GREENLEE/ NRN GRAHAM COUNTIES NE OF TUCSON. DRY CONDITIONS PREVAILED ELSEWHERE ACROSS SE AZ AT THIS TIME. CLOUD TOPS ASSOCIATED WITH THE MCS ACROSS NERN SONORA WERE WARMING DURING THE PAST 1-2 HOURS. THE PAST 3 HOURS OF RUC HRRR SOLUTIONS HAVE YIELDED FAIRLY MARKEDLY DIFFERENT RESULTS REGARDING PRECIP POTENTIAL THE REST OF TONIGHT. 2 SOLUTIONS YIELDED PRECIP TO REDEVELOP AROUND MIDNIGHT JUST NORTH AND WEST OF TUCSON AND CONTINUE TO MOVE WEST ACROSS THE TOHONO O`ODHAM NATION. ONE SOLUTION YIELDED VERY LITTLE PRECIP THE REST OF TONIGHT. BASED ON THE 20/00Z UPPER PLOTS...AM INCLINED TO BELIEVE THAT ISOLATED TO PERHAPS SCATTERED SHOWERS AND A FEW THUNDERSTORMS MAY OCCUR THRU ABOUT 20/09Z DUE TO DIFFLUENCE ALOFT. RAINFALL AMOUNTS SHOULD BE QUITE LIGHT AS PER EACH RUC HRRR SOLUTION. THUS...NO CHANGES OF SIGNIFICANCE FOR THE INHERITED GRIDDED DATA POP FIELDS FOR THE REST OF TONIGHT. MIN TEMPS LATER TONIGHT ARE FORECAST TO BE WITHIN A DEGREE-OR-TWO OF NORMAL. PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION BELOW FOR ADDITIONAL DETAIL. && .PREV DISCUSSION /155 PM MST FRI JUL 19 2013/...WITH THE LOW PRESSURE OVER SONORA AND ATTENDANT CLOUDS DRIFTING ONLY SLOWLY WEST THEN UP THE BAJA/GULF AREA THE NEXT FEW DAYS...MORNING CLOUDS COULD CONTINUE TO HINDER ATMOSPHERIC HEATING...BUT IF THIS HINDRANCE IS OVERCOME...STORMS THAT DEVELOP COULD PRODUCE HEAVY RAIN. MODEL DEPICTIONS OF THE LOW TRACK AND THE MOISTURE FIELDS TEND TO FAVOR MUCH OF THE AREA STILL BEING AFFECTED BY CLOUD COVER AND ONCE AGAIN LIMITING HEATING...WHEREAS SUNDAY WE MAY WARM UP QUICKER AND BE ABLE TO GENERATE MORE THUNDERSTORM COVERAGE. FOR NEXT WEEK...A SECONDARY AREA OF LOW PRESSURE WILL MOVE ACROSS NRN MEXICO...POSSIBLY INFLUENCING OUR WEATHER ONCE AGAIN AND KEEPING THE CHANCES FOR THUNDERSTORMS AT OR ABOVE CLIMATOLOGICAL NORMALS...KD && .AVIATION...SCATTERED -SHRA AND ISOLATED -TSRA MOSTLY ENDING AROUND 20/09Z. SCATTERED TO NUMEROUS SHRA/TSRA TO OCCUR SATURDAY AFTERNOON AND CONTINUE INTO SATURDAY EVENING. MVFR CONDITIONS WITH BRIEF WIND GUSTS TO AROUND 45 KTS WITH THE STRONGER TSRA. OTHERWISE...CLOUD DECKS GENERALLY 5-9K FT AGL AND SURFACE WIND MAINLY LESS THAN 10 KTS THRU SATURDAY EVENING OR 21/06Z. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...UPPER LOW OVER SONORA MEXICO WILL MAINTAIN A MOIST EASTERLY FLOW ACROSS SOUTHERN ARIZONA THROUGH THE WEEKEND. THE COMBINATION OF THE UPPER LOW AND ABUNDANT ATMOSPHERIC MOISTURE WILL BRING ABOUT PLENTY OF CONVECTION THAT WILL BE ABLE TO OCCUR ANYTIME WITH A FOCUS DURING THE AFTERNOON AND EVENING HOURS. THE STRONGER THUNDERSTORMS WILL BE CAPABLE OF PRODUCING HEAVY DOWNPOURS AS WELL AS GUSTY AND ERRATIC WINDS. RELATIVE HUMIDITIES WILL REMAIN MOIST WITH THE NORMAL DIURNAL WIND PATTERNS DISRUPTED AT TIMES THIS WEEKEND BY CONVECTION. THE SHOWERS AND THUNDERSTORMS WILL BECOME LESS NUMEROUS AND MORE DIURNAL IN NATURE NEXT WEEK AS THE LOW MOVES FURTHER WEST AND THE AIR MASS BECOMES A BIT DRIER. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON DISCUSSION/AVIATION...FRANCIS PREVIOUS DISCUSSION...DROZD FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
255 AM PDT SAT JUL 20 2013 .SYNOPSIS... A MOIST EAST FLOW PATTERN WILL BRING INCREASING MONSOONAL MOISTURE WITH PERIODS OF SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MONDAY...DECREASING ON TUESDAY. FLASH FLOODING IS POSSIBLE IN RECENT BURN AREAS. WARMER AND DRIER FOR THE LATTER HALF OF NEXT WEEK WITH SOUTHWEST FLOW ALOFT. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TODAY THROUGH MONDAY)... IN THE NEAR TERM...THE MESOSCALE CONVECTIVE SYSTEM OVER SAN BERNARDINO COUNTY WILL CONTINUE TO MOVE WESTWARD AND SLOWLY WEAKEN BASED ON SATELLITE AND RADAR TRENDS. MODELS HAVE TYPICALLY BEEN OF LIMITED VALUE IN HANDLING THIS SYSTEM WITH THE 02Z HRRR THE LEAST CLUELESS OF THE BUNCH. IT AT LEAST SHOWED A CIRCULATION CENTER AND MOSTLY ASSOCIATED SHOWERS TRANSLATING WESTWARD ACROSS SOUTHERN CALIFORNIA THIS MORNING. THE MODELS HAVE ALSO BEEN LESS THAN HELPFUL WITH REGARD TO THE MORE RECENT CONVECTION IN SOUTHWEST ARIZONA AND THE FAR EASTERN DESERTS OF SOUTHERN CALIFORNIA. THAT CONVECTION CONTINUES TO MOVE SLOWLY WESTWARD AND COULD AT LEAST PUSH SOME OUTFLOW ACROSS THE LOWER DESERTS OF SOUTHERN CALIFORNIA. HIGH PRESSURE OVER NEVADA WILL DIRECT AN INCREASINGLY MOIST MONSOONAL AIR MASS INTO SOUTHWEST CALIFORNIA THROUGH SUNDAY. PRECIPITABLE WATER VALUES A LITTLE OVER ONE INCH FRIDAY AFTERNOON WILL INCREASE TO 1.4 INCHES THIS AFTERNOON AND 1.7 INCHES SUNDAY AFTERNOON. A DRYING TREND WILL BEGIN MONDAY. THIS WILL BRING PERIODS OF SHOWERS AND ISOLATED THUNDERSTORMS INTO MONDAY. SOME PRECIPITATION COULD MOVE WEST OF THE MOUNTAINS TONIGHT THROUGH SUNDAY NIGHT. THE ABUNDANT MID AND HIGH LEVEL MOISTURE WILL LIMIT SURFACE HEATING AND THE POTENTIAL FOR STRONGER AFTERNOON THUNDERSTORMS SOMEWHAT THROUGH SUNDAY. HOWEVER...GIVEN THE INCREASING MOISTURE CONTENT...THUNDERSTORMS THAT DO DEVELOP COULD PRODUCE LOCALLY HEAVY RAINFALL. FLASH FLOOD GUIDANCE THRESHOLDS FOR NEW BURN AREAS ARE THREE TENTHS OF AN INCH OF RAINFALL IN 30 MINUTES...SOMETHING THAT WOULD BE POSSIBLE WITH ANY OF THE THUNDERSTORMS. HENCE...A FLASH FLOOD WATCH FOR THE BURN AREAS HAS BEEN ISSUED THROUGH SUNDAY EVENING. AS THE HIGHER LEVEL MOISTURE BEGINS TO DECREASE MONDAY WITH THE MID LEVEL MOISTURE REMAINING IN PLACE...THERE WOULD BE GREATER POTENTIAL FOR DEVELOPMENT OF STRONGER THUNDERSTORMS MONDAY AFTERNOON WITH GREATER POTENTIAL FOR FLASH FLOODING IN THE MOUNTAINS AND DESERTS...NOT JUST IN RECENT BURN AREAS. THE INCREASING CLOUD COVER WILL BRING COOLING FOR INLAND AREAS INTO SUNDAY WITH SLOW WARMING FOR MONDAY. THE MARINE LAYER AND ONSHORE LOWER LEVEL FLOW WILL CONTINUE TO KEEP COASTAL AREAS COOLER WITH AREAS OF NIGHT AND MORNING LOW CLOUDS AND FOG. && .LONG TERM (TUESDAY THROUGH FRIDAY)... A WEAK TROUGH OF LOW PRESSURE NEAR THE WEST COAST SHOULD BRING A DRYING TREND FOR THE MIDDLE TO LATTER PART OF THE WEEK. THERE MAY STILL BE ENOUGH RESIDUAL MOISTURE FOR AFTERNOON THUNDERSTORMS OVER THE MOUNTAINS TUESDAY. AS THE MOISTURE DECREASES...INLAND AREAS WILL WARM. && .AVIATION... 200930Z...COAST/VALLEYS...STRATUS WITH BASES 1200-1500 FT MSL HAS MOVED 15-20SM. LOW CLOUDS EXPECTED TO CLEAR IN THE VALLEYS 15-17Z AND ALONG THE COAST 18-20Z...WITH SOME CLOUDS CLINGING TO THE BEACHES THROUGH THE AFTERNOON. STRATUS RETURNING TO COASTAL AIRPORTS 01-03Z WITH SIMILAR BASES AND TOPS. OTHERWISE...SCT-BKN CLOUDS AOA 8000 FT MSL AND AREAS OF SMOKE FROM THE MOUNTAIN FIRE...ESPECIALLY IN THE SOUTHERN INLAND EMPIRE. A SLIGHT CHANCE OF LIGHT SHOWERS AND THUNDERSTORMS BEGINNING SAT AFTERNOON. ANY TSTMS THAT DEVELOP WILL LIKELY PRODUCE LITTLE RAIN AND GUSTY SFC WINDS. MTNS/DESERTS...SCT-BKN CLOUDS AOA 8000 FT MSL. EASTERLY WINDS MAY INCREASE EARLY THIS MORNING FOR A SHORT TIME OVER THE LOW DESERTS AS OUTFLOW FROM THUNDERSTORMS MOVES THROUGH. OTHERWISE...A CHANCE OF SHOWERS AND THUNDERSTORMS BEGINNING SAT AFTERNOON...WITH THE BEST CHANCES OVER THE MTN RIDGES. BASES WILL BE NEAR 8-10K FT WITH TOPS TO 40K FT. && .MARINE... LONG PERIOD SOUTH-SOUTHWEST SWELL CURRENTLY PEAKING WITH A REINFORCING 3-4 FT/16-17 SEC PERIOD SWELL ARRIVING LATER TODAY. THIS WILL CONTINUE ELEVATED SURF AND STRONG RIP CURRENTS ALONG SOUTH AND SOUTHWEST FACING BEACHES THROUGH THE WEEKEND WITH LOCAL SURF SETS AROUND 7 FEET POSSIBLE...MAINLY IN ORANGE COUNTY. HIGH TIDES WILL BE ABOVE 7 FEET EACH EVENING SAT THROUGH MON. THE COMBINATION OF ELEVATED SURF AND HIGH TIDES MAY PRODUCE MINOR COASTAL FLOODING ALONG VULNERABLE LOW-LYING AREAS. A BEACH HAZARDS STATEMENT CONTINUES THROUGH SUN EVENING. SURF AND SWELL WILL DIMINISH EARLY NEXT WEEK. && .FIRE WEATHER... A MOIST EAST FLOW PATTERN WILL BRING INCREASING MONSOONAL MOISTURE WITH PERIODS OF SHOWERS AND ISOLATED THUNDERSTORMS WITH WETTING RAINS THROUGH MONDAY...DECREASING ON TUESDAY. THUNDERSTORM WIND GUSTS TO 40 MPH ARE POSSIBLE WITH FLASH FLOODING POSSIBLE IN RECENT BURN AREAS. WARMER AND DRIER FOR THE LATTER HALF OF NEXT WEEK WITH SOUTHWEST FLOW ALOFT. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR BURN AREAS OF THE RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO COUNTY DESERTS...SAN DIEGO COUNTY MOUNTAINS. BEACH HAZARDS STATEMENT THROUGH SUNDAY EVENING FOR THE BEACHES IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL AREAS. PZ...NONE. && $$ PUBLIC...17 AVIATION/MARINE...TS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
856 PM MDT SUN JUL 21 2013 .UPDATE... && .SHORT TERM...CWA IS MOSTLY STORM FREE EXCEPT FOR A FEW SHOWERS REMAINING ACROSS PARK COUNTY. THE EARLIER ACTIVITY ACROSS LINCOLN AND WASHINGTON COUNTIES HAVE LONG SINCE ENDED. WILL STILL KEEP ISOLATED POPS OVER THE FAR NORTHEAST CORNER IN CASE THE CONVECTION OVER NEBRASKA AND EASTERN WYOMING MAKES IT FARTHER SOUTH INTO COLORADO LATER TONIGHT. .AVIATION...SURFACE BOUNDARY PUSHING NORTHWARD OVER DOUGLAS AND ELBERT COUNTIES WILL SHIFT WINDS MORE S-SW OVER TERMINALS DURING THE NEXT HOUR. OTHERWISE MOSTLY CLEAR SKIES TONIGHT. && .PREV DISCUSSION... /ISSUED 257 PM MDT SUN JUL 21 2013/ SHORT TERM...STRONG OUTFLOW FROM T-STORMS UP IN NEBRASKA LAST NIGHT...BACKED ACROSS NORTHEAST COLORADO EARLIER TODAY. THIS SHALLOW MOIST AIRMASS SIGNIFICANTLY INFLUENCED TEMPERATURES EAST OF THE MOUNTAINS TODAY. CURRENT TEMPERATURES ARE RUNNING SEVERAL DEGS BEHIND THOSE YESTERDAY AT THIS TIME...THEREBY CREATING A STRONG CAP UP AROUND 750 MBS NEAR THE FOOTHILLS...AND UP AROUND 700 MBS FARTHER OUT OVER THE PLAINS ACCORDING RUC SOUNDINGS AND CROSS SECTIONS. BENEATH THIS PSUEDO-FRONTAL INVERSION...BNDRY LAYER CAPE VALUES ARE NOW NEAR 700 J/KG UP AGAINST THE FOOTHILLS AND CLOSE TO 1500 J/KG IN THE FAR NORTHEAST. DO SEE THIS ENERGY BEING TAPPED NEAR THE FOOTHILLS EVEN WITH ISOLATED LOW TOP CONVECTION DRIFTING OFF THE FOOTHILLS WITH ALL OF THE CIN IN THIS AREA. FARTHER OUT ON THE PLAINS...COULD SEE THE WEAK SHORTWAVE DISTURBANCE NOW SWINGING OVER SERN WYOMING TAPPING INTO SOME OF THIS PENNED UP ENERGY RESULTING IN A FEW T-STORMS IN THE FAR NORTHEAST COUNTIES AFTER 5 PM MDT TODAY. MORE LIKELY WE/LL SEE THIS CONVECTION DURING THE EVENING HOURS WITH THE LAST OF THE CIN ERRODING AS THE SHORTWAVE PASSES BY. NOT LOOKING FOR ANY SEVERE WX OUT OF THEM...JUST PERHAPS SOME SMALL HAIL...BRIEF HEAVY RAIN AND GUSTY OUTFLOW WINDS TO AROUND 50 MPH. STORMS SHOULD END EARLIER TONIGHT WITH ARRIVAL OF DRIER AND MORE STABLE AIR BEHIND THIS SHORTWAVE. HOWEVER...LINGERING LOW LEVEL MOISTURE MAY AGAIN RESULT IN AREAS OF LOW CLOUDS AND/OR PATCHY FOG IN THE FAR NORTHEAST TOWARDS MORNING. ON MONDAY...AIRMASS APPEARS MUCH DRIER AND WARMER. WITH THE UPPER RIDGE STRENGTHENING TO OUR WEST..AND BARRING ANY UNFORESEEN MOIST OUTFLOW FROM DOWNSTREAM STORMS...SHOULD SEE TEMPERATURES EASILY CLIMBING INTO THE 90S ON THE PLAINS TOMORROW...WITH 70S AND 80S IN THE MTNS. IT/S NOT OUT THE QUESTION WE COULD SEE LOW 90S POPPING UP IN A FEW SPOTS ALONG THE UPPER COLORADO IN GRAND COUNTY. DO NOT ANTICIPATE ANY PRECIPITATION/T-STORMS ON MONDAY. LONG TERM...OVERALL NO BIG CHANGES TO THE ONGOING TRENDS IN THE FORECAST. THE UPPER LEVEL RIDGE WILL BE CENTERED NEAR THE GREAT BASIN FOR MONDAY NIGHT INTO TUESDAY. AS A RESULT...A DRY AND STABLE NORTHWESTERLY FLOW ALOFT WILL BE OVER THE CWFA. PLENTY OF LOW LEVEL MOISTURE OVER THE NORTHEAST PLAINS...BUT TOO SUBSIDENT IN THE MID LEVELS TO ALLOW THE INITIATION OF DEEP CONVECTION FOR MOST OF THE FORECAST AREA. A WEAK SYSTEM PASSING ACROSS THE NRN GREAT PLAINS AND INTO THE MID WEST COULD BE ENOUGH TO INITIATE TSTMS OVER THE FAR NERN CORNER OF CO LATE TUESDAY. FOR THE REST OF THE WEEK...THE CENTER OF RIDGE SHIFTS EASTWARD WHICH OPENS UP WESTERN CO TO SUBTROPICAL MID MOISTURE FM THE SOUTH. BETTER TSTM COVERAGE SHOULD HELP TO SHAVE A FEW DEGREES OF THE AFTN TEMPERATURES AS WELL. THE ECMWF AND GFS BOTH SHOW BOTH DEVELOP DECENT QPF OVER THE AREA LATE WEDNESDAY AND THURSDAY...WITH A BIT OF DRYING ON FRIDAY. MDLS DIFFER AS TO HOW MUCH MOISTURE WILL BE AVAILABLE OVER THE WEEKEND SO SLGT CHC SHOULD SUFFICE FOR NOW. AVIATION...VFR CONDITIONS ANTICIPATED FOR THE NEXT 24 HOURS UNDER NORTHWEST FLOW ALOFT. NORTH-NORTHEAST SURFACE WINDS UNDER 12 KTS AT MOST DENVER AREA AIRPORTS SHOULD GRADUALLY BECOME EASTERLY AT SIMILAR SPEEDS AFTER 23Z AND LINGER THROUGH EARLY EVENING...THEN GO TO A DRAINAGE WIND OVERNIGHT. DIA AND APA COULD SEE GUSTY SOUTHERLY WINDS OF 10-20 KTS DEVELOPING IN THE EVENING WITH THE FORMATION A TIGHT PRES GRADIENT JUST EAST OF THE METRO AREA. AFTER SAY 08Z...SHOULD SEE WIND SPEEDS RELAX AND RESUME MORE TYPICAL SPEEDS UNDER 12KS. ON MONDAY SOUTHERLY WINDS UNDER 12KS ARE FORECAST TO GO WEST-NORTHWEST BY LATE MORNING AT SIMILAR SPEEDS. WITH FEW CLOUDS AROUND...SHOULD SEE DAYTIME TEMPERATURES RETURNING TO THE 90S. HYDROLOGY...NO CONCERNS AT THIS TIME. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ENTREKIN LONG TERM....COOPER AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
307 PM MDT SAT JUL 20 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 230 PM MDT SAT JUL 20 2013 THE HIGHER LEVEL MSTR PLUME HAS SHIFTED SOUTH OF THE AREA TODAY...BUT LOW LEVEL MSTR REMAINS IN PLACE WITH DEW POINTS MOSTLY IN THE 50S OVR THE SERN PLAINS AND AROUND 50 IN THE SAN LUIS VALLEY. EXPECTING MOST OF THE CONVECTIVE ACTIVITY THIS EVENING TO BE OVR AND NR THE MTS. SO FAR TODAY...THE SHOWERS THAT HAVE DEVELOPED WERE MOVING AROUND 10-12 MPH TO THE SE OR SSE. THIS SLOW MOVEMENT WL AGAIN LEAD TO THE CONCERN FOR LOCALLY HEAVY RAIN ON THE BURN SCARS AND THE POTENTIAL FOR FLASH FLOODING IF A HEAVIER STORM MOVES OVR OR DEVELOPS ON A BURN SCAR. THE NAM AND HRRR MOVE SOME STORMS OFF THE MTS AND ACRS THE I-25 CORRIDOR...MAINLY OVR EL PASO AND NRN PUEBLO COUNTIES THIS EVENING. A SHORTWAVE TROF MOVING ACRS NERN AND EAST CENTRAL CO TONIGHT IS EXPECTED TO BRING SOME CONVECTIVE ACTIVITY TO THOSE AREAS...BUT AT THIS TIME THE HI RES MODELS ARE KEEPING THAT MAINLY NORTH OF THE CWA...BUT COULD SEE SOME SHOWERS/TSTMS IN KIOWA COUNTY ASSOC WITH THE DISTURBANCE. WE COULD SEE A FEW LINGERING SHOWERS OVR THE MTS UNTIL MIDNIGHT OR A LITTLE LATER...BUT THEN BY MORNING ALL AREAS SHOULD BE DRY. ON SUN IT LOOKS LIKE SOME ISOLD TO SCT SHOWER/TSTMS COULD DEVELOP OVR THE HYR TRRN AROUND NOON...WITH THE BEST CHANCES BEING OVR THE SW MTS AND THE SRN SANGRES. A WEAK DISTURBANCE IS EXPECTED TO MOVE ACRS NERN CO IN THE AFTERNOON...AND THE NAM HAS SOME CONVECTIVE ACTIVITY FIRING UP IN NORTHEAST AND EAST CENTRAL CO...INCLUDING KIOWA AND CROWLEY COUNTIES BY EVENING. THE GFS KEEPS THE CONVECTION OVR NERN CO. FOR NOW WL GO WITH A DRY FORECAST FOR THE FAR SERN PLAINS SUN AFTERNOON. HIGH TEMPS ON SUN LOOK A COUPLE OR FEW DEGREES WARMER THAN TODAY. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 230 PM MDT SAT JUL 20 2013 HOT AND MAINLY DRY CONDITIONS EXPECTED MON AND TUESDAY AS UPPER RIDGE RE-AMPLIFIES OVER THE WESTERN US. MOISTURE PLUME WILL REMAIN SUPPRESSED TO THE SOUTH BOTH DAYS...THOUGH PERHAPS JUST ENOUGH RESIDUAL LOW LEVEL MOISTURE WILL LINGER TO PRODUCE AN ISOLATED HIGH BASED TSRA OVER THE MOUNTAINS...ESPECIALLY MON. WITH HEIGHTS RISING AND 700 MB TEMPS CLIMBING TOWARD 20C...EXPECT MAX TEMPS MON/TUE WILL REACH 100F PLUS OVER THE LOWER ARKANSAS VALLEY...WITH 80S/90S ELSEWHERE. FRONT DROPS THROUGH THE EASTERN PLAINS LATE TUE NIGHT/EARLY WED...LEADING TO A RENEWED WESTWARD PUSH OF MOISTURE BY WED AFTERNOON. ECMWF HAS TRENDED TOWARD THE GFS ON WED...AND BOTH MODELS NOW SUGGEST INCREASED CHANCES FOR TSRA OVER THE EASTERN MOUNTAINS AND PLAINS WED AFTERNOON/EVENING. WESTERN MOUNTAINS AND VALLEYS SHOULD ALSO SEE AN UPSWING IN TSRA WED...AS WEAK PUSH OF MID LEVEL MOISTURE WORKS NORTHWARD UNDERNEATH THE UPPER RIDGE AXIS. FOR LATE WEEK INTO THE WEEKEND...STILL APPEARS AN INCREASE IN CONVECTION IS POSSIBLE MANY AREAS THU-SAT...THOUGH DIFFERENCES BETWEEN THE EUROPEAN AND GFS ARISE BEGINNING THU...AS EURO BRINGS A STRONG TROUGH THROUGH THE AREA...WHILE GFS IS WEAKER/SLOWER. GFS IS THUS RATHER DRY THU...THEN MOISTENS THE AREA FRI/SAT...WHILE FASTER ECMWF IS WETTER THU/FRI BEFORE DRYING SLIGHTLY ON SAT. HAVE FOLLOWED THE MORE CONSISTENT GFS AT THIS POINT...BUT MAIN MESSAGE OF BOTH MODELS IS A RETURN OF FAIRLY WIDESPREAD CONVECTION BY WEEK`S END. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 230 PM MDT SAT JUL 20 2013 SHOWERS AND THUNDERSTORMS COULD OCCUR AT OR IN THE VCNTY OF KCOS...KALS AND KPUB MAINLY BEFORE 02Z-03Z. IT IS POSSIBLE THAT SOME HEAVY RAIN COULD AFFECT THE TERMINAL SITES WITH BRIEF MVFR OR IFR CONDITIONS. OTHERWISE VFR CONDITIONS ARE EXPECTED. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...PETERSEN AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1125 PM MDT FRI JUL 19 2013 .UPDATE... ISSUED AT 730 PM MDT FRI JUL 19 2013 UPDATED TO CANCEL FLASH FLOOD WATCH FOR EL PASO AND TELLER COUNTIES. LATEST HIGHER RESOLUTION MODEL RUNS OF THE HRRR AND RAP ARE NOT INDICATING AS MUCH UPSTREAM DEVELOPMENT AS PREVIOUS RUNS. THIS IS SUPPORTED BY CURRENT RADARS INDICATING A ONLY FEW STORMS IN PARK COUNTY WEST OF TARRYALL RESERVOIR...AS WELL AS A FEW MORE STORMS ACROSS THE NORTHERN MTS OF SUMMIT...GRAND AND LARIMAR COUNTIES AT THIS TIME. RADAR AND MODEL TRENDS HAVE THIS STORMS MOVING SOUTH AND WEAKENING THROUGH THE REST OF THE EVENING...WITH THE THREAT OF FLASH FLOODING DIMINISHING AS WELL. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 238 PM MDT FRI JUL 19 2013 AN UPR RIDGE WL REMAIN CENTERED OVR NV TONIGHT AND SATURDAY. A UPR DISTURBANCE WL CONTINUE MOVING SOUTH ACRS THE FORECAST AREA TONIGHT. THERE IS PLENTY OF MOISTURE OVER THE AREA AS WELL. ALL THE INGREDIENTS SEEM TO BE IN PLACE TO BRING WIDESPREAD PCPN OVR AND NR THE MTS...WITH SCT ACTIVITY OVR THE SERN PLAINS. THE STEERING FLOW WL REMAIN FAIRLY LIGHT...RESULTING AND SLOW MOVING STORMS AND THUS UNDER THE HEAVIER STORMS...LOCALLY HEAVY RAIN COULD FALL. THIS BECOMES A BIG CONCERN IF IT OCCURS OVR THE BURNS SCARS AS MUD AND ASH FLOWS COULD OCCUR. WL LEAVE THE FLASH FLOOD WATCH IN EFFECT FOR EL PASO AND TELLER COUNTIES. AS THE UPR DISTURBANCE MOVES SOUTHWARD OVR THE AREA...BOTH THE RAP13 AND NAM SHOW THE FOCUS OF PCPN SHIFTING SOUTHWARD THIS EVENING OVR THE SRN MTS AND SOUTH OF HIGHWAY 50. THE HRRR ALSO SHOWS WIDESPREAD PCPN AND CHANCES FOR RAIN OVR SRN AREAS...BUT ALSO INCREASES PCPN CHANCES OVR EL PASO...TELLER COUNTIES AND PUEBLO COUNTIES DURING THE EVENING HOURS. OVERNIGHT...PCPN CHANCES ARE EXPECTED TO DECREASE OR END FROM NORTH TO SOUTH...WITH SOME LIGHT PCPN POSSIBLY LINGERING THRU THE NIGHT OVR FAR SOUTHERN AREAS. IT LOOKS DRIER IN THE UPR LEVELS ON SATURDAY AS THE MSTR PLUME SHIFTS SOUTH OF THE AREA...BUT THERE WL STILL BE PLENTY OF LOW LEVEL MSTR TO WORK WITH FOR SCT TO LIKELY POPS OVR THE MTS AND PROBABLY ISOLD TO SCT POPS OVR THE SERN PLAINS. STORMS SHOULD BE FAIRLY SLOW MOVING AGAIN AND WE COULD SEE SOME LOCALIZED HEAVY RAIN. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 238 PM MDT FRI JUL 19 2013 UPPER LEVEL FLOW TURNS SLIGHTLY MORE NORTHWESTERLY SUNDAY...WHICH WILL TEND TO PUSH THE MOIST PLUME SOUTH OF THE STATE INTO NM AND AZ BY AFTERNOON. MODELS SHOW WEAK FRONTAL BOUNDARY DISSIPATING SOMEWHERE OVER THE ERN PLAINS OF CO...WITH DECREASING LOW LEVEL MOISTURE AS UPSLOPE WINDS WEAKEN. SUSPECT TSRA WILL STAY ISOLATED AND LIMITED TO MAINLY THE HIGHER TERRAIN SUN AFTERNOON AND EVENING...AND WILL END QUICKLY BY LATE EVENING WITH LITTLE IN THE WAY OF UPPER SUPPORT. MAX TEMPS SUN SHOULD CREEP UPWARD A DEGF OR TWO...THOUGH 700 MB TEMPS SUGGEST RATHER HOT MET GUIDANCE MAXES MAY BE JUST A TAD TOO WARM. SIMILAR SET-UP MON/TUE...AS WEAK SURFACE FRONT REFORMS OVER NORTHEAST COLORADO AND AIR MASS OVER SOUTHERN COLORADO CONTINUES TO DRY. AGAIN EXPECT ISOLATED MOUNTAIN CONVECTION BOTH DAYS...THOUGH COVERAGE AND RAINFALL AMOUNTS WILL BE RATHER SPARSE. 700 MB TEMPS CREEP UPWARD INTO THE 18C-20C RANGE...WHICH SHOULD PRODUCE A FEW 100F PLUS READINGS OVER THE EASTERN PLAINS BOTH DAYS. ON WED...FRONT DROPS SOUTH OVER THE PLAINS LEADING TO A RENEWED WESTWARD SURGE OF MOISTURE OVER THE EASTERN MOUNTAINS AND PLAINS BY AFTERNOON. GFS AND ECMWF ARE SIMILAR WITH SURFACE FEATURES...BUT ONLY GFS BREAKS OUT CONVECTION THU EVENING...WHILE ECMWF STAYS DRY. WILL LEAN TOWARD THE WETTER SOLUTION OF THE GFS FOR NOW...GIVEN THE DEEPER MOISTURE AND INSTABILITY BEHIND THE FRONT. FARTHER WEST...LOW GRADE MONSOON REDEVELOPS WED AS SLIGHTLY DEEPER MID LEVEL MOISTURE PUSHES BACK INTO THE STATE...LEADING TO BETTER TSRA COVERAGE THAN MON/TUE. PAST WED...MOISTURE LOOKS TO SLOSH BACK AND FORTH ACROSS THE EASTERN PLAINS...WITH PERHAPS A DECREASE IN PRECIP CHANCES THU AND AN INCREASE FRI. OVER THE MOUNTAINS...UPSWING IN CONVECTION LOOKS POSSIBLE FRI AS WELL...ESPECIALLY AS LAST FEW MODEL RUNS OF BOTH THE ECMWF AND GFS TRY TO BUILD THE UPPER RIDGE EASTWARD INTO TX...ALLOWING A RENEWED INFLUX OF MOISTURE FROM THE SOUTH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1125 PM MDT FRI JUL 19 2013 VFR CONDITIONS EXPECTED AT TAF SITES THROUGH THE REST OF THE NIGHT WITH MID AND HIGH LEVEL CONVECTIVE DEBRIS CLOUDS CONTINUE TO DIMINISH. WITH THIS EVENINGS PRECIPITATION...COULD SEE SOME PATCHY FOG DEVELOPING ACROSS THE AREA THROUGH THE EARLY MORNING HOURS WITH BEST CHANCES AT COS AND ALS...THOUGH NOT ENOUGH CONFIDENCE TO PUT IN TAFS AT THIS TIME. MODELS INDICATING LESS COVERAGE OF STORMS TOMORROW AS DRIER AIR IN THE WEAK NORTHERLY FLOW ALOFT MOVES INTO THE AREA. STILL SHOULD SEE SCATTERED STORMS ACROSS THE MTS WITH BEST CHANCES OF STORMS AFFECTING TERMINAL BEING AT COS...THOUGH HAVE KEPT VCTS IN PLACE AT THIS TIME. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MW SHORT TERM...28 LONG TERM...PETERSEN AVIATION...MW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1107 AM EDT SAT JUL 20 2013 .SYNOPSIS... ONE MORE HOT AND HUMID DAY IS EXPECTED TODAY ALONG WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AS A COLD FRONT APPROACHES FROM THE GREAT LAKES. THIS FRONT WILL BRING RELIEF FROM THE EXCESSIVE HEAT AND HUMIDITY ON SUNDAY. MORE SEASONABLE BUT HUMID CONDITIONS ARE EXPECTED FOR MUCH OF NEXT WEEK WITH SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1050 AM UPDATE... NOTING A LOT OF SUBSIDENCE AND DRY AIR ALOFT WHICH IS TENDING TO BREAK THE DEBRIS CLOUDS THAT HAVE MOVED ACROSS FROM NY STATE EARLIER THIS MORNING ACROSS MOST OF THE REGION. ALSO NOTED AN AREA OF SHOWERS THAT WORKED INTO NW MA/SW NH AROUND 14Z FROM NY STATE TENDED TO DRY UP AS IT MOVED OUT OF THE BERKSHIRES. STARTING TO SEE LINE OF SHOWERS/TSTMS STARTING TO DEVELOP ACROSS UPSTATE NY AS WELL AS OVER S CENTRAL NY AT 1430Z. HAVE UPDATED GRIDS TO SLOW DOWN THE PRECIP ESPECIALLY OVER EASTERN AREAS UNTIL AROUND 18Z AND BEYOND. DEWPTS ARE MUCH HIGHER THAN FORECAST...MAINLY IN THE MID 70S NEAR AND S OF THE MASS PIKE WHERE THEY APPEAR TO BE POOLING...SO MAY BE A FOCUS OF ANY CONVECTION THAT MAY DEVELOP PROBABLY AFTER 18Z. USED A BLEND OF OUR PREVIOUS FORECAST WITH THE HRRR MODEL...WHICH APPEARS TO HAVE THIS SAME FOCUS. OTHER CONVECTIVE PARAMETERS ARE MARGINAL...WITH MID LEVEL LAPSE RATES ON ORDER OF 6C/KM...FOR LOW LEVEL LAPSE RATES ARE MUCH HIGHER OVER CENTRAL AND EASTERN AREAS AS SEEN ON SPC MESO ANALYSIS. SPC DID UPDATE THEIR CONVECTIVE OUTLOOK TO SHIFT IT A BIT FURTHER S. TEMPS ALSO A BIT HIGHER THAN FORECAST...WITH 92 AT 14Z AT KBOS. HAVE ADJUSTED TEMPS A BIT HIGHER FROM PREVIOUS FORECAST. ALSO ADJUSTED CLOUD COVER TO BRING CURRENT. REMAINDER OF FORECAST LOOKED PRETTY GOOD BUT DID UPDATE TO BRING CURRENT. PREVIOUS DISCUSSION... THE BEST CHANCE FOR ORGANIZED STORMS AND SEVERE WEATHER WILL BE IN WESTERN NEW ENGLAND AS 0-6KM SHEAR INCREASES TO 35 KT BY LATE AFTERNOON...BUT BEST LOW LEVEL CONVERGENCE MAY BE FURTHER E NEAR THE COASTAL PLAIN. PRIMARY MODE OF CONVECTION SHOULD BE MULTICELLULAR LINE SEGMENTS WITH DAMAGING WIND THE GREATEST THREAT FROM ANY SEVERE STORMS...ALONG WITH HEAVY DOWNPOURS IN HIGH PWAT AIRMASS. ANOTHER RATHER HOT AND HUMID DAY ACROSS SNE. IF THE CLOUD COVER REMAIN BROKEN AND THIN...IT WONT TAKE MUCH FOR TEMPS TO SOAR INTO THE LOW TO MID 90S AS IT IS ALREADY FAIRLY WARM PER THIS MORNING LOWS. MAIN HEATING WILL BE ACROSS RI AND E MA WHERE MOST SUNSHINE IS EXPECTED. DEWPOINTS IN THE LOWER-MID 70S WILL RESULT IN HEAT INDICES OF 100-105 FOR HOTTEST SPOTS IN THE LOWER CT VALLEY AND MUCH OF E MA AND RI WHERE HEAT ADVISORIES ARE IN EFFECT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT... SCT SHOWERS AND TSTMS MAY LINGER ACROSS THE COASTAL PLAIN AND S COAST INTO THE EVENING BEFORE ACTIVITY DISSIPATES AND MOVES OFFSHORE. COLD FRONT WILL MOVE S ACROSS THE REGION TONIGHT BUT NOT CLEARING THE S COAST UNTIL CLOSER TO 12Z SUN. SUNDAY... WEAK FRONT WILL STALL S OF NEW ENG WITH WEAK HIGH PRES BUILDING TO THE N. WHILE IT WILL BE NOTICEABLY COOLER...850 MB TEMPS 14-16C SO IT WILL STILL BE RATHER WARM WITH TEMPS IN THE MID TO UPPER 80S...COOLER HIGHER TERRAIN AS WELL AS IMMEDIATE COAST WHERE COASTAL SEABREEZES ARE LIKELY. DEWPOINTS MAY DROP INTO THE UPPER 50S ACROSS N ZONES...BUT LIKELY REMAIN IN THE MID 60S CLOSER TO THE COAST. LOW RISK FOR AN ISOLD SHOWER SUN AFTERNOON...OTHERWISE DRY WEATHER WITH PT-MOSUNNY SKIES. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HEADLINES... * DRY AND SEASONABLE INTO MONDAY. * SHOWERS AND THUNDERSTORMS RETURN FOR TUESDAY INTO WEDNESDAY. * AN ACTIVE WEATHER PATTERN SETUP CONTINUES THROUGH THE LATE WEEK. * NO SIGN OF OPPRESSIVE HEAT AND HUMIDITY RETURNING ANY TIME SOON. */OVERVIEW AND MODEL CONSENSUS... WHILE BETTER CONTINUITY HAS EMERGED INTO THE MIDWEEK...THERE IS STILL SOME UNCERTAINTY CONCERNING THE ABNORMAL SETUP SET TO EVOLVE INTO THE LATTER PORTION OF THE FORECAST. LATEST OPERATIONAL RUNS OF THE ECMWF HAVE COME INTO BETTER AGREEMENT WITH ITS ENSEMBLE MEAN WHILE THE RUN-TO-RUN CONTINUITY OF THE GFS HAS NOT EXHIBITED THE SAME. AM IN FAVOR OF THE MORE AMPLIFIED PATTERN WITH THE BAROCLINIC ZONE DIPPING INTO THE GULF COASTAL STATES AS EMPHASIZED BY THE ECMWF INTO THE FOLLOWING WEEKEND. AGREE WITH WPC ASSESSMENT AND ACCOMPANYING FORECAST GUIDANCE. THUS NOT SEEING A RETURN OF OPPRESSIVE HEAT AND HUMIDITY ANY TIME SOON RATHER A MORE ACTIVE AND SEASONABLE PATTERN. SURFACE OUTCOMES REMAIN UNCERTAIN SO FAR OUT IN THE FORECAST BUT IT IS LIKELY THAT PACIFIC WAVES TRANSLATING AND EVOLVING THROUGH THE LONG WAVE PATTERN WILL NOT ONLY AMPLIFY THE PATTERN BUT ALSO LEAD TO SUCCESSIVE ROUNDS OF SHOWERS AND THUNDERSTORMS. */DAY-TO-DAY DETAILS... */SUNDAY NIGHT INTO MONDAY... WILL KEEP THE FORECAST PERIOD MOSTLY DRY KEEPING COOLER AND DRIER HIGH PRESSURE IN CONTROL. POOR MID-LEVEL LAPSE RATES. SUBSTANTIAL MID- LEVEL DRY AIR IN PLACE WITH ACCOMPANYING RIDGING. LITTLE IN THE WAY OF DYNAMICS AND ONLY LOW-LEVEL FORCING WILL BE ALONG SEA- BREEZE FRONTS AS THE EARLY WEEKEND COLD FRONT WILL STALL SOUTH OF NEW ENGLAND...ORIENTED WEST TO EAST IN PROXIMITY TO SOUTHERN PA/NJ. THERE ARE SUBTLE HINTS OF PERHAPS SOME PRECIPITATION...THE 20.0Z NAM THE MOST PRONOUNCED SOLUTION. EVALUATING FURTHER...THE NORTHEASTERN CONUS IS WITHIN THE RIGHT-REAR QUADRANT OF THE UPPER-LEVEL JET COINCIDENT WITH THE MID-LEVEL /H85/ THERMAL GRADIENT. BUT WITH THE DRY AIR AND POOR LAPSE RATES...JUST DO NOT HAVE THE CONFIDENCE IN GOING WITH CHANCE POPS. WILL KEEP CONDITIONS CLOSE TO SEASONABLE. BETTER CHANCE FOR CLOUDS DURING THE PERIOD WILL BE ALONG THE SOUTH-COAST WITH CLOSER PROXIMITY TO THE AFOREMENTIONED COLD FRONT. */MONDAY NIGHT INTO WEDNESDAY... THERE IS BETTER AGREEMENT ON THE EVOLUTION OF PACIFIC DISTURBANCE TRANSLATING THROUGH THE MARITIME FLOW AND INTERACTING WITH A STRONG AREA OF LOW PRESSURE ACROSS NORTHERN QUEBEC. THE GENERAL THEME AT THE SURFACE IS FOR AN AREA OF LOW PRESSURE TO DEVELOP NORTH OF THE GREAT LAKES REGION...UNDERGO MATURATION AND OCCLUSION DURING THE TIME FRAME INTO NORTHERN QUEBEC. THE SUBSEQUENT INFLUENCE OF RETURN SOUTHERN FLOW ACROSS THE NORTHEASTERN CONUS LIFTS THE OFFSHORE FRONT NORTH AS A WARM FRONT EARLY IN THE PERIOD...FOLLOWED BY A TRAILING ATTENDANT COLD FRONT TO THE AFOREMENTIONED LOW LATE INTO WEDNESDAY. WHILE SOME DIFFERENCES CONCERNING TIMING AND SUBSEQUENT SURFACE OUTCOMES...THERE IS A GENERAL THEME OF PERIODS OF SHOWERS AND THUNDERSTORMS LOCALIZED WHERE LOW-LEVEL CONVERGENCE ALONG FRONTAL BOUNDARIES COUPLED WITH MID- TO UPPER-LEVEL DYNAMICS ALOFT RESULTING IN DEEP-LAYER ASCENT. CHANCE POPS WARRANTED...ESPECIALLY MONDAY NIGHT INTO TUESDAY NIGHT. SHEAR IS PRONOUNCED...BUT INSTABILITY IS LACKING LIKELY DUE TO POOR MID- LEVEL LAPSE RATES AND ANTICIPATED CLOUDY MESS. NOTED BY THE PRIOR FORECASTER...HIGH PWATS UP TO 2 INCHES PRESENTS THE THREAT OF HEAVY RAINFALL AND LOCALIZED FLOODING. WILL PREVAIL WITH CONDITIONS AT OR SLIGHTLY ABOVE SEASONABLE WITH EXPECTED SOUTHERLY FLOW. SHOULD SEE THE RETURN OF MUGGY CONDITIONS. WINDS BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING TUESDAY NIGHT INTO WEDNESDAY. */THURSDAY INTO THE WEEK... GREATER CONFIDENCE TOWARDS THE DETERMINISTIC 19.12Z ECMWF WITH IMPROVED AGREEMENT WITH ITS ENSEMBLE MEAN...AND BETTER RUN-TO-RUN CONSISTENCY. STILL THERE IS SOME UNCERTAINTY WITH HOW PACIFIC ENERGY EVOLVES THROUGH THE BASE OF THE BROADER TROUGHING PATTERN OVER THE EASTERN TWO-THIRDS OF THE CONUS...THOUGH WPC/HPC HAS NOTED THAT FORECAST GUIDANCE HAS TRENDED WITH A MORE AMPLIFIED TROUGH PATTERN WITH A COLD UPPER-LOW DIPPING INTO THE GREAT LAKES REGION. AS STATED YESTERDAY...CONTINUED CERTAINTY THAT THE NORTHEASTERN CONUS REMAINS IN THE MARITIME FLOW RESULTING IN AN ACTIVE WEATHER PATTERN AND SEASONABLE CONDITIONS. CHANCE POPS WARRANTED WITH THE EXPECTATION FOR SHOWERS AND THUNDERSTORMS AT TIMES...NOT SPECULATING ON SEVERE WEATHER AT THIS TIME...THOUGH IF THE TROUGH EFFECTIVELY TAPS INTO TROPICAL MOISTURE...THEN HEAVY RAIN AND POTENTIAL FLOODING WILL BE A CONCERN. WILL KEEP CONDITIONS AT SEASONABLE LEVELS. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH SUNDAY... HAZE AND HIGH CLOUDS TO BE AN ISSUE THIS MORNING...GRADUALLY BURNING OFF THROUGH THE DAY. EXPECTING AN INCREASE IN AREAL COVERAGE OF SHRA/TSRA INTO THIS AFTERNOON ACROSS WESTERN AND CENTRAL PORTIONS OF NEW ENGLAND. HAVE PREVAILED -SHRA VCTS ACCORDINGLY MAINLY FOR THE AFTERNOON PERIOD AROUND THE MASS TURNPIKE...SULKING SOUTH TO THE COAST TOWARDS SUNDOWN AND OUT TO SEA INTO THE EVENING. WITH ANY TSRA...LOW-VFR CIGS WITH MVFR/IFR VSBYS WILL BE POSSIBLE. UNCERTAINTY ON LOCATION AND EVOLUTION OF TSRA SO DID NOT PREVAIL IN THE TAF. GUSTY SW WINDS AHEAD OF AN APPROACHING COLD FRONT ANTICIPATED TO SWEEP THROUGH THE TERMINALS LATE TONIGHT INTO SUNDAY MORNING...WINDS BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING. COASTAL FOG MAY DEVELOP AHEAD OF THE COLD FRONT. SHOULD SEE IMPROVEMENT THEREAFTER WITH DRIER AIR FILTERING IN. PREVAILING VFR FOR SUNDAY WITH LIGHT NORTH-NORTHWEST WINDS...SEA-BREEZES ALONG THE SHORES. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP STORMS OUT OF THE TERMINAL FOR NOW. GUSTY SOUTHWEST WINDS DURING THE DAY. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. PREVAILING -SHRA VCTS WITH EXPECTATION OF AFTERNOON STORMS...BUT UNCERTAIN ON SPECIFIC IMPACTS. OUTLOOK...SUNDAY NIGHT INTO THURSDAY... SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE. VFR. LIGHT AND VARIABLE WINDS. SEA-BREEZES ALONG THE SHORELINES. MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE. WINDS TURNING SOUTHERLY AND GUSTY AT TIMES. PERIODS OF SHRA/TSRA. WILL SEE TEMPO MVFR-IFR IMPACTS WITH WET WEATHER. COULD SEE A RETURN OF SOUTH-COASTAL DENSE FOG. COLD FRONT LATE IN THE PERIOD WILL FORCE WINDS TO BACK NORTH-NORTHWEST. THURSDAY...MODERATE CONFIDENCE. AFOREMENTIONED COLD FRONT MAY LINGER IN PROXIMITY TO SOUTHERN NEW ENGLAND ACTING AS A FOCUS FOR CONTINUED WET WEATHER AND PERHAPS MVFR- IFR IMPACTS AT TIMES. COASTAL FOG MAY ALSO BE AN ISSUE ALONG THE SOUTH-COAST. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH SUNDAY. THROUGH THIS EVENING...A FEW GUSTS TO 25 KT POSSIBLE OVER THE NEARSHORE WATERS THIS AFTERNOON. SEAS REMAIN AROUND 5-6 FT ON THE OPEN SOUTHERN WATERS AS WELL AS RI SOUND. SCT AFTN/EVENING TSTMS POSSIBLE. TONIGHT...SW WINDS WILL SHIFT TO THE NW LATE TONIGHT AS COLD FRONT MOVES THROUGH. SCA SEAS CONTINUE OVER SOUTHERN WATERS. TSTMS POSSIBLE SOUTH WATERS AS FRONTAL DEPARTS SLOWLY. SUNDAY...E/SE WINDS DEVELOPING MAINLY UNDER 15 KT. SEAS SUBSIDING BELOW SCA THRESHOLDS. OUTLOOK...SUNDAY NIGHT INTO THURSDAY... SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE. HIGH PRESSURE IN CONTROL. LIGHT AND VARIABLE WINDS GRADUALLY BACKING OUT OF THE SOUTH. SEAS BELOW 5 FEET OVER ALL WATERS. MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE. INCREASE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS. WINDS OUT OF THE SOUTH-SOUTHWEST INCREASING. GUSTS UP TO 20 KTS POSSIBLE. FETCH RESULTING IN SEAS BUILDING ABOVE 5 FEET OVER THE SOUTH-SOUTHEAST WATERS. COLD FRONT SLIDES INTO THE WATERS WEDNESDAY ALLOWING WINDS TO DIMINISH. COASTAL FOG MAY BE AN ISSUE ALONG THE SOUTH-SHORE WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS. THURSDAY...MODERATE CONFIDENCE. COLD FRONT WAVERS AS IT STALLS IN PROXIMITY TO SOUTHERN NEW ENGLAND. CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE. THE LIGHTER WIND FLOW ALLOWS SEAS TO SUBSIDE. COASTAL FOG MAY CONTINUE TO BE AN ISSUE WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR CTZ002>004. MA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MAZ005>007- 011>021. NH...NONE. RI...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR RIZ001>005. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR ANZ235-254. SMALL CRAFT ADVISORY UNTIL 8 AM EDT SUNDAY FOR ANZ255-256. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...KJC/SIPPRELL/EVT SHORT TERM...KJC LONG TERM...SIPPRELL AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
749 AM EDT SAT JUL 20 2013 .SYNOPSIS... ONE MORE HOT AND HUMID DAY IS EXPECTED TODAY ALONG WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AS A COLD FRONT APPROACHES FROM THE GREAT LAKES. THIS FRONT WILL BRING RELIEF FROM THE EXCESSIVE HEAT AND HUMIDITY ON SUNDAY. MORE SEASONABLE BUT HUMID CONDITIONS ARE EXPECTED FOR MUCH OF NEXT WEEK WITH SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 730 AM UPDATE... CONVECTION OVER THE EASTERN GREAT LAKES IS CERTAINLY GOING TO HAVE CONSEQUENCES UPON THE REGIONS WEATHER. INCREASING CLOUD COVER IS LIKELY TO LIMIT BOUNDARY LAYER DESTABILIZATION AND WARMING TEMPERATURES AT THE SURFACE. ECHO PREVIOUS FORECASTERS THOUGHTS ABOUT IMPACTS JUST TO HOW UNSTABLE IT GETS THIS AFTERNOON AND POTENTIAL STRONG TO SEVERE WEATHER OUTCOMES. FEEL THE LATEST HRRR AND THE WRF-ARW HAVE A GOOD HANDLE ON THE PRESENT SITUATION. SHOWERS AND AN ISOLATED THUNDERSTORM ARE POSSIBLE DURING THE MORNING HOURS. THIS ENERGY MAY DISSIPATE INTO A SLIGHTLY DRIER AIRMASS PER THE 12Z CHATHAM SOUNDING. BUT AS ALSO DISCERNED FROM THE CHATHAM SOUNDING...THERE IS A LOT OF POTENTIAL INSTABILITY SHOULD THE BOUNDARY LAYER DESTABILIZE. DIFFICULT TO PIN DOWN EXACTLY WHERE AND WHEN ANY THUNDERSTORMS WILL DEVELOP AND EVOLVE FOR TODAY. AS NOTED BY THE PREVIOUS FORECASTER...MLCAPES FORECAST TO REACH 1000-2000 J/KG BUT THERE IS SOME UNCERTAINTY WITH THE AMOUNT OF SUNSHINE DUE TO CONVECTIVE REMNANTS AND CLOUD COVER DRIFTING IN FROM THE WEST. MID-LEVEL TEMPS ARE FORECAST TO BE ABOUT 3-4 DEGREES COOLER THAN YESTERDAY SO THERE WILL BE MUCH LESS OF A CAP AND RIGHT ENTRANCE REGION OF UPPER JET WILL BE APPROACHING FROM THE NORTH LATER TODAY. FOCUS IS ON THE DEVELOPMENT OF A PRE-FRONTAL TROUGH AHEAD OF THE MAIN SURFACE COLD FRONT WHICH MAY AID IN FOCUSING LOW LEVEL CONVERGENCE FOR CONVECTION...THERE IS STILL AN EXPECTATION FOR SCATTERED THUNDERSTORMS TO DEVELOP THIS AFTERNOON SHOULD CLOUD COVER CLEAR OUT AS SUGGESTED BY THE HRRR. AGAIN...THE BEST CHANCE FOR ORGANIZED STORMS AND SEVERE WEATHER WILL BE IN WESTERN NEW ENGLAND AS 0-6KM SHEAR INCREASES TO 35 KT BY LATE AFTERNOON...BUT BEST LOW LEVEL CONVERGENCE MAY BE FURTHER E NEAR THE COASTAL PLAIN. PRIMARY MODE OF CONVECTION SHOULD BE MULTICELLULAR LINE SEGMENTS WITH DAMAGING WIND THE GREATEST THREAT FROM ANY SEVERE STORMS...ALONG WITH HEAVY DOWNPOURS IN HIGH PWAT AIRMASS. ANOTHER RATHER HOT AND HUMID DAY ACROSS SNE. IF THE CLOUD COVER REMAIN BROKEN AND THIN...IT WONT TAKE MUCH FOR TEMPS TO SOAR INTO THE LOW TO MID 90S AS IT IS ALREADY FAIRLY WARM PER THIS MORNING LOWS. MAIN HEATING WILL BE ACROSS RI AND E MA WHERE MOST SUNSHINE IS EXPECTED. DEWPOINTS 70-75 WILL RESULT IN HEAT INDICES OF 100-105 FOR HOTTEST SPOTS IN THE LOWER CT VALLEY AND MUCH OF E MA AND RI WHERE HEAT ADVISORIES ARE IN EFFECT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT... SCT SHOWERS AND TSTMS MAY LINGER ACROSS THE COASTAL PLAIN AND S COAST INTO THE EVENING BEFORE ACTIVITY DISSIPATES AND MOVES OFFSHORE. COLD FRONT WILL MOVE S ACROSS THE REGION TONIGHT BUT NOT CLEARING THE S COAST UNTIL CLOSER TO 12Z SUN. SUNDAY... WEAK FRONT WILL STALL S OF NEW ENG WITH WEAK HIGH PRES BUILDING TO THE N. WHILE IT WILL BE NOTICEABLY COOLER...850 MB TEMPS 14-16C SO IT WILL STILL BE RATHER WARM WITH TEMPS IN THE MID TO UPPER 80S...COOLER HIGHER TERRAIN AS WELL AS IMMEDIATE COAST WHERE COASTAL SEABREEZES ARE LIKELY. DEWPOINTS MAY DROP INTO THE UPPER 50S ACROSS N ZONES...BUT LIKELY REMAIN IN THE MID 60S CLOSER TO THE COAST. LOW RISK FOR AN ISOLD SHOWER SUN AFTERNOON...OTHERWISE DRY WEATHER WITH PT-MOSUNNY SKIES. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HEADLINES... * DRY AND SEASONABLE INTO MONDAY. * SHOWERS AND THUNDERSTORMS RETURN FOR TUESDAY INTO WEDNESDAY. * AN ACTIVE WEATHER PATTERN SETUP CONTINUES THROUGH THE LATE WEEK. * NO SIGN OF OPPRESSIVE HEAT AND HUMIDITY RETURNING ANY TIME SOON. */OVERVIEW AND MODEL CONSENSUS... WHILE BETTER CONTINUITY HAS EMERGED INTO THE MIDWEEK...THERE IS STILL SOME UNCERTAINTY CONCERNING THE ABNORMAL SETUP SET TO EVOLVE INTO THE LATTER PORTION OF THE FORECAST. LATEST OPERATIONAL RUNS OF THE ECMWF HAVE COME INTO BETTER AGREEMENT WITH ITS ENSEMBLE MEAN WHILE THE RUN-TO-RUN CONTINUITY OF THE GFS HAS NOT EXHIBITED THE SAME. AM IN FAVOR OF THE MORE AMPLIFIED PATTERN WITH THE BAROCLINIC ZONE DIPPING INTO THE GULF COASTAL STATES AS EMPHASIZED BY THE ECMWF INTO THE FOLLOWING WEEKEND. AGREE WITH WPC ASSESSMENT AND ACCOMPANYING FORECAST GUIDANCE. THUS NOT SEEING A RETURN OF OPPRESSIVE HEAT AND HUMIDITY ANY TIME SOON RATHER A MORE ACTIVE AND SEASONABLE PATTERN. SURFACE OUTCOMES REMAIN UNCERTAIN SO FAR OUT IN THE FORECAST BUT IT IS LIKELY THAT PACIFIC WAVES TRANSLATING AND EVOLVING THROUGH THE LONGWAVE PATTERN WILL NOT ONLY AMPLIFY THE PATTERN BUT ALSO LEAD TO SUCCESSIVE ROUNDS OF SHOWERS AND THUNDERSTORMS. */DAY-TO-DAY DETAILS... */SUNDAY NIGHT INTO MONDAY... WILL KEEP THE FORECAST PERIOD MOSTLY DRY KEEPING COOLER AND DRIER HIGH PRESSURE IN CONTROL. POOR MID-LEVEL LAPSE RATES. SUBSTANTIAL MID- LEVEL DRY AIR IN PLACE WITH ACCOMPANYING RIDGING. LITTLE IN THE WAY OF DYNAMICS AND ONLY LOW-LEVEL FORCING WILL BE ALONG SEA- BREEZE FRONTS AS THE EARLY WEEKEND COLD FRONT WILL STALL SOUTH OF NEW ENGLAND...ORIENTED WEST TO EAST IN PROXIMITY TO SOUTHERN PA/NJ. THERE ARE SUBTLE HINTS OF PERHAPS SOME PRECIPITATION...THE 20.0Z NAM THE MOST PRONOUNCED SOLUTION. EVALUATING FURTHER...THE NORTHEASTERN CONUS IS WITHIN THE RIGHT-REAR QUADRANT OF THE UPPER-LEVEL JET COINCIDENT WITH THE MID-LEVEL /H85/ THERMAL GRADIENT. BUT WITH THE DRY AIR AND POOR LAPSE RATES...JUST DO NOT HAVE THE CONFIDENCE IN GOING WITH CHANCE POPS. WILL KEEP CONDITIONS CLOSE TO SEASONABLE. BETTER CHANCE FOR CLOUDS DURING THE PERIOD WILL BE ALONG THE SOUTH-COAST WITH CLOSER PROXIMITY TO THE AFOREMENTIONED COLD FRONT. */MONDAY NIGHT INTO WEDNESDAY... THERE IS BETTER AGREEMENT ON THE EVOLUTION OF PACIFIC DISTURBANCE TRANSLATING THROUGH THE MARITIME FLOW AND INTERACTING WITH A STRONG AREA OF LOW PRESSURE ACROSS NORTHERN QUEBEC. THE GENERAL THEME AT THE SURFACE IS FOR AN AREA OF LOW PRESSURE TO DEVELOP NORTH OF THE GREAT LAKES REGION...UNDERGO MATURATION AND OCCLUSION DURING THE TIME FRAME INTO NORTHERN QUEBEC. THE SUBSEQUENT INFLUENCE OF RETURN SOUTHERN FLOW ACROSS THE NORTHEASTERN CONUS LIFTS THE OFFSHORE FRONT NORTH AS A WARM FRONT EARLY IN THE PERIOD...FOLLOWED BY A TRAILING ATTENDANT COLD FRONT TO THE AFOREMENTIONED LOW LATE INTO WEDNESDAY. WHILE SOME DIFFERENCES CONCERNING TIMING AND SUBSEQUENT SURFACE OUTCOMES...THERE IS A GENERAL THEME OF PERIODS OF SHOWERS AND THUNDERSTORMS LOCALIZED WHERE LOW-LEVEL CONVERGENCE ALONG FRONTAL BOUNDARIES COUPLED WITH MID- TO UPPER-LEVEL DYNAMICS ALOFT RESULTING IN DEEP-LAYER ASCENT. CHANCE POPS WARRANTED...ESPECIALLY MONDAY NIGHT INTO TUESDAY NIGHT. SHEAR IS PRONOUNCED...BUT INSTABILITY IS LACKING LIKELY DUE TO POOR MID- LEVEL LAPSE RATES AND ANTICIPATED CLOUDY MESS. NOTED BY THE PRIOR FORECASTER...HIGH PWATS UP TO 2 INCHES PRESENTS THE THREAT OF HEAVY RAINFALL AND LOCALIZED FLOODING. WILL PREVAIL WITH CONDITIONS AT OR SLIGHTLY ABOVE SEASONABLE WITH EXPECTED SOUTHERLY FLOW. SHOULD SEE THE RETURN OF MUGGY CONDITIONS. WINDS BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING TUESDAY NIGHT INTO WEDNESDAY. */THURSDAY INTO THE WEEK... GREATER CONFIDENCE TOWARDS THE DETERMINISTIC 19.12Z ECMWF WITH IMPROVED AGREEMENT WITH ITS ENSEMBLE MEAN...AND BETTER RUN-TO-RUN CONSISTENCY. STILL THERE IS SOME UNCERTAINTY WITH HOW PACIFIC ENERGY EVOLVES THROUGH THE BASE OF THE BROADER TROUGHING PATTERN OVER THE EASTERN TWO-THIRDS OF THE CONUS...THOUGH WPC/HPC HAS NOTED THAT FORECAST GUIDANCE HAS TRENDED WITH A MORE AMPLIFIED TROUGH PATTERN WITH A COLD UPPER-LOW DIPPING INTO THE GREAT LAKES REGION. AS STATED YESTERDAY...CONTINUED CERTAINTY THAT THE NORTHEASTERN CONUS REMAINS IN THE MARITIME FLOW RESULTING IN AN ACTIVE WEATHER PATTERN AND SEASONABLE CONDITIONS. CHANCE POPS WARRANTED WITH THE EXPECTATION FOR SHOWERS AND THUNDERSTORMS AT TIMES...NOT SPECULATING ON SEVERE WEATHER AT THIS TIME...THOUGH IF THE TROUGH EFFECTIVELY TAPS INTO TROPICAL MOISTURE...THEN HEAVY RAIN AND POTENTIAL FLOODING WILL BE A CONCERN. WILL KEEP CONDITIONS AT SEASONABLE LEVELS. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH SUNDAY... HAZE AND HIGH CLOUDS TO BE AN ISSUE THIS MORNING...GRADUALLY BURNING OFF THROUGH THE DAY. EXPECTING AN INCREASE IN AREAL COVERAGE OF SHRA/TSRA INTO THIS AFTERNOON ACROSS WESTERN AND CENTRAL PORTIONS OF NEW ENGLAND. HAVE PREVAILED -SHRA VCTS ACCORDINGLY MAINLY FOR THE AFTERNOON PERIOD AROUND THE MASS TURNPIKE...SULKING SOUTH TO THE COAST TOWARDS SUNDOWN AND OUT TO SEA INTO THE EVENING. WITH ANY TSRA...LOW-VFR CIGS WITH MVFR/IFR VSBYS WILL BE POSSIBLE. UNCERTAINTY ON LOCATION AND EVOLUTION OF TSRA SO DID NOT PREVAIL IN THE TAF. GUSTY SW WINDS AHEAD OF AN APPROACHING COLD FRONT ANTICIPATED TO SWEEP THROUGH THE TERMINALS LATE TONIGHT INTO SUNDAY MORNING...WINDS BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING. COASTAL FOG MAY DEVELOP AHEAD OF THE COLD FRONT. SHOULD SEE IMPROVEMENT THEREAFTER WITH DRIER AIR FILTERING IN. PREVAILING VFR FOR SUNDAY WITH LIGHT NORTH-NORTHWEST WINDS...SEA-BREEZES ALONG THE SHORES. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP STORMS OUT OF THE TERMINAL FOR NOW. GUSTY SOUTHWEST WINDS DURING THE DAY. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. PREVAILING -SHRA VCTS WITH EXPECTATION OF AFTERNOON STORMS...BUT UNCERTAIN ON SPECIFIC IMPACTS. OUTLOOK...SUNDAY NIGHT INTO THURSDAY... SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE. VFR. LIGHT AND VARIABLE WINDS. SEA-BREEZES ALONG THE SHORELINES. MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE. WINDS TURNING SOUTHERLY AND GUSTY AT TIMES. PERIODS OF SHRA/TSRA. WILL SEE TEMPO MVFR-IFR IMPACTS WITH WET WEATHER. COULD SEE A RETURN OF SOUTH-COASTAL DENSE FOG. COLD FRONT LATE IN THE PERIOD WILL FORCE WINDS TO BACK NORTH-NORTHWEST. THURSDAY...MODERATE CONFIDENCE. AFOREMENTIONED COLD FRONT MAY LINGER IN PROXIMITY TO SOUTHERN NEW ENGLAND ACTING AS A FOCUS FOR CONTINUED WET WEATHER AND PERHAPS MVFR- IFR IMPACTS AT TIMES. COASTAL FOG MAY ALSO BE AN ISSUE ALONG THE SOUTH-COAST. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH SUNDAY. TODAY...A FEW GUSTS TO 25 KT POSSIBLE OVER THE NEARSHORE WATERS THIS AFTERNOON. SCA SEAS OVER THE OPEN SOUTHERN WATERS. SCT AFTN/EVENING TSTMS POSSIBLE. TONIGHT...SW WINDS WILL SHIFT TO THE NW LATE TONIGHT AS COLD FRONT MOVES THROUGH. SCA SEAS CONTINUE OVER SOUTHERN WATERS. TSTMS POSSIBLE SOUTH WATERS AS FRONTAL DEPARTS SLOWLY. SUNDAY...E/SE WINDS DEVELOPING MAINLY UNDER 15 KT. SEAS SUBSIDING BELOW SCA THRESHOLDS. OUTLOOK...SUNDAY NIGHT INTO THURSDAY... SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE. HIGH PRESSURE IN CONTROL. LIGHT AND VARIABLE WINDS GRADUALLY BACKING OUT OF THE SOUTH. SEAS BELOW 5 FEET OVER ALL WATERS. MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE. INCREASE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS. WINDS OUT OF THE SOUTH-SOUTHWEST INCREASING. GUSTS UP TO 20 KTS POSSIBLE. FETCH RESULTING IN SEAS BUILDING ABOVE 5 FEET OVER THE SOUTH-SOUTHEAST WATERS. COLD FRONT SLIDES INTO THE WATERS WEDNESDAY ALLOWING WINDS TO DIMINISH. COASTAL FOG MAY BE AN ISSUE ALONG THE SOUTH-SHORE WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS. THURSDAY...MODERATE CONFIDENCE. COLD FRONT WAVERS AS IT STALLS IN PROXIMITY TO SOUTHERN NEW ENGLAND. CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE. THE LIGHTER WIND FLOW ALLOWS SEAS TO SUBSIDE. COASTAL FOG MAY CONTINUE TO BE AN ISSUE WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR CTZ002>004. MA...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR MAZ005>007-011>021. NH...NONE. RI...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR RIZ001>005. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR ANZ235-254. SMALL CRAFT ADVISORY UNTIL 8 AM EDT SUNDAY FOR ANZ255-256. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...KJC/SIPPRELL SHORT TERM...KJC LONG TERM...SIPPRELL AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
355 AM EDT Sat Jul 20 2013 .NEAR TERM [Today and Tonight]... The high-resolution model guidance appears to have been reasonably accurate in depicting an increase in convective coverage and rain rates around 06-08 UTC. The showers that have developed so far appear to be dominated by warm rain processes - low-topped convection that is very efficient in producing rainfall. The TLH airport recorded around one half inch of rain in just under a half hour with one of these showers. The HRRR and preponderance of CAM guidance shows a general 1-2" of rain on average can be expected through mid-afternoon over most of our Florida zones (where the heaviest rain is most likely). However, the vast majority of those models also show localized amounts in the 7-9" range, which would likely be sufficient to cause localized flash flooding. Because of this, we have issued a Flash Flood Watch in effect until 23 UTC for all of our Florida zones. PoPs were adjusted to show 60-80% values this morning across our Florida zones, with "likely" PoPs (60-70%) spreading north into our Alabama and Georgia zones in the late morning and afternoon. The abundance of rain and cloud cover will likely once again restrict the diurnal temperature range, so high temperatures were kept cooler than normal values, and similar to the inherited forecast. Indications are that convective coverage will diminish between 21 and 03 UTC, with a lull tomorrow evening. && .SHORT TERM [Sunday Through Monday]... While at this time yesterday it had appeared that there would be some legitimate hope that a brief period of Upper level ridging could push far enough northward in the Gulf of Mexico to at least give our region a brief break in the unsettled weather, each consecutive run of the ECMWF continues to squash that little bit of hope. If the Upper ridge stays weak and in the Central Gulf of Mexico, the probability of conditions that are wetter and cooler than climo will increase, and for those looking for a break in the persistent Upper trough (and accompanying sunnier and drier conditions) may have to wait until next summer. && .LONG TERM [Monday Night through Friday]... The GFS and ECMWF forecast a 500mb trough to develop over the Southeast over the upcoming work week. It`s difficult to forecast specifics in such patterns as there will undoubtedly be minor short waves rotating through this broader trough, which can help trigger periods of active deep moist convection (sometimes even overnight). The best approach is to "broad brush" above-average rain chances (generally 50-60% each day, and 20-30% each night) across the region, which is near the GFS-ECMWF MOS PoP blend. Temperatures will be near average, with highs in the lower to mid 90s (inland) and lows in the 70s. && .AVIATION [through 12 UTC Sunday]... Some IFR-MVFR CIGS could develop at our three northern terminals (DHN, ABY, VLD) out ahead of the rain showers that are developing near the Gulf. These will likely diminish as the rain advances north this morning. Meanwhile, MVFR-VFR should prevail at TLH and ECP, with tropical rain showers having the potential to reduce visibility at times to IFR. These tropical rain showers will spread inland during the day, with the potential to eventually affect the remaining terminals (ABY, DHN, VLD). Rain will diminish by 21-03 UTC with VFR through the evening. && .MARINE... Moderate onshore winds today have created slightly higher seas than expected, so did bump up seas about 1 foot across the board for today. Winds and seas will diminish a bit back to more typical summertime levels on Sunday and Monday, before becoming moderate again out of the west by mid week, as the surface pressure pattern increases slightly. && .FIRE WEATHER... Red flag conditions are not expected for the next several days. && .HYDROLOGY... Numerous tropical rain showers and rain bands are beginning to develop early this morning in a very moist environment. The humid air mass is due to a large plume of tropical moisture. A variety of model guidance shows a general inch of rainfall averaged across all of the Florida panhandle and big bend. However, there are also indications that localized amounts could be well in excess of that. Small heavy rain bands are not uncommon in a tropical environment such as this, and they can lead to localized flash flooding. The rain should begin to decrease in coverage closer to sunset. Impacts on area rivers are difficult to pinpoint at this time, but certainly areas near Bruce, Lamont, and Newport in Florida should be on alert for potential rises back to Flood Stage. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 84 73 90 74 91 / 80 30 60 30 40 Panama City 84 76 88 76 88 / 70 50 60 30 40 Dothan 87 73 90 73 91 / 70 30 60 30 50 Albany 87 73 91 74 91 / 70 30 60 30 50 Valdosta 85 72 92 73 92 / 70 30 60 30 50 Cross City 88 73 90 73 90 / 60 30 60 20 40 Apalachicola 84 76 88 75 88 / 70 50 50 20 40 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...FLASH FLOOD WATCH through this evening for Calhoun-Central Walton-Coastal Bay-Coastal Dixie-Coastal Franklin-Coastal Gulf-Coastal Jefferson-Coastal Taylor-Coastal Wakulla- Gadsden-Holmes-Inland Bay-Inland Dixie-Inland Franklin- Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla- Inland Walton-Jackson-Lafayette-Leon-Liberty-Madison- South Walton-Washington. GA...None. AL...None. GM...None. && $$ NEAR TERM...Lamers SHORT TERM...Gould LONG TERM...Fournier AVIATION...Lamers MARINE...Gould FIRE WEATHER...Lamers HYDROLOGY...Lamers/Gould
AREA FORECAST DISCUSSION
NWS LINCOLN IL
853 PM CDT SUN JUL 21 2013 .DISCUSSION... ISSUED 850 PM CDT SUN JUL 21 2013 UPDATED THE FORECAST TONIGHT TO INCREASE CHANCES OF SHOWERS ALONG WITH A FEW THUNDERSTORMS. ALSO NUDGED UP LOW TEMPERATURES A DEGREE OR TWO TO AROUND 70F...DUE TO MOIST DEWPOINTS CURRENTLY IN THE LOW TO MID 70S. A FEW POCKETS OF LOCALLY HEAVY RAINS OF 1.5 TO 3 INCHES ALSO TO OCCUR TONIGHT ESPECIALLY FROM I-72 SOUTH...AS JACKSONVILLE HAS EXPERIENCED SINCE 5 PM. THE HRRR MODEL HAS BEEN HANDLING THIS WEATHER SYSTEM THE BEST SO FAR SO LEANED ON THIS MODEL FOR TONIGHT`S FORECAST. SHOWERS AND A FEW THUNDERSTORMS TO SPREAD INTO EASTCENTRAL IL NEXT NEW HOURS... THEN DIMINISH FROM WEST TO EAST LATE THIS EVENING AND OVERNIGHT. A SHORT WAVE MOVING INTO CENTRAL IL THIS EVENING AND EXITING SE OF AREA MONDAY MORNING WILL KEEP LIKELY CHANCES OF SHOWERS AND FEW THUNDERSTORMS PAST SUNDOWN TONIGHT AND LIKELY CHANCES CONTINUE OVER EASTERN IL OVERNIGHT...WHILE DIMINISHING TO SLIGHT CHANCE IN THE WEST. A QUASI STATIIONARY FRONTAL BOUNDARY OVER NE PARTS OF IA/IL AND INTO CENTRAL INDIANA WILL GRADUALLY WEAKEN THROUGH MONDAY...WITH CENTRAL/SE IL STAYING ON THE SOUTH SIDE (MILD/MOIST SIDE) OF THE BOUNDARY. TEMPS CURRENTLY IN THE 70S TO ONLY SLIP TOWARD 70F FOR LOWS OVERNIGHT WHICH JACKSONVILLE IS CURRENTLY DOWN TO WITH HEAVY RAINS PAST FEW HOURS FROM THUNDERSTORMS. EXPECT LIGHT SSE TO VARIABLE WINDS TONIGHT WITH SOME FOG POSSIBLE OVERNIGHT INTO MID MORNING MONDAY WITH VSBYS DOWN TO 1-3 MILES. 07 && .AVIATION... ISSUED 700 PM CDT SUN JUL 21 2013 LEANED ON THE HRRR MODEL FOR QPF FIELDS WITH ARRIVAL OF SHOWERS AND THUNDERSTORMS FROM WEST TO EAST DURING THIS EVENING AND DIMINISHING OVERNIGHT. HAVE MVFR CEILINGS 1.5-3K FT POSSIBLE TONIGHT WITH PRECIPITATION ALONG WITH VSBYS RESTRICTED DOWN TO 1.5-3 MILES IN HEAVIER RAIN SHOWERS. SHOWERS AND A FEW THUNDERSTORMS ARE WEST OF I-55 AND TO SPREAD EAST TO DEC AND CMI IN THE NEXT FEW HOURS...THEN DIMINISH FROM WEST TO EAST FROM 05Z-08Z. SOME FOG POSSIBLE OVERNIGHT INTO MON MORNING WITH VSBYS 2-4 MILES AND THEN LIFTING TO LIGHT FOG/HAZE OF 4-6 MILES BETWEEN 14-15Z AS MVFR CEILINGS LIFT TO VFR LATER MON MORNING. SOUTH WINDS TO STAY FAIRLY LIGHT FROM 4-8 KTS THIS EVENING AND LIGHT AND VARIABLE OVERNIGHT AND SW 4-7 KTS MONDAY. 07 && .PREV DISCUSSION... ISSUED 239 PM CDT SUN JUL 21 2013 MAIN CONCERNS THIS PACKAGE WILL CONTINUE TO BE PCPN CHANCES FOR THE SHORT TERM AND THEN PCPN CHANCES AGAIN AT THE END OF THE WEEK AND INTO THE WEEKEND...IN THE LONG TERM PERIOD. MODELS SHOW GOOD AGREEMENT WITH KEEPING THE MID LEVEL NORTHWEST FLOW IN PLACE...WITH A RIDGE BUILDING OUT OVER THE ROCKIE MOUNTAIN REGION...ALL THROUGH MID WEEK. THE NORTHWEST FLOW WILL ALSO CONTINUE INTO THE EXTENDED PERIOD AND MODELS LOOK OK HERE TOO UNTIL LATE IN THE WEEK AND THE WEEKEND. ECMWF APPEARS TO BE STRONGER WITH A MID LEVEL SYSTEM COMING DOWN INTO THE AREA DURING THE END OF THE PERIOD. SHORT TERM...TONIGHT THROUGH WEDNESDAY FRONTAL SYSTEM OVER THE AREA THIS AFTERNOON WILL GRADUALLY WASHOUT TONIGHT THROUGH TOMORROW AS A STRONGER WEATHER SYSTEM DEVELOPS OUT IN THE PLAINS. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS THE ENTIRE CWA THIS EVENING AND THEN IN THE EAST AFTER MIDNIGHT...WITH CHANCES BACK TO THE WEST. LIGHT SHOWERS ARE ONGOING BUT REMNANTS OF AN MCS IN IOWA HAVE CONTINUED TO GET STRONGER IN SOUTH CENTRAL IOWA AND WILL MOVE EAST-SOUTHEAST INTO THE CWA THIS EVENING AND THROUGH TONIGHT. BELIEVE THIS LINE/COMPLEX OF STORMS WILL FOLLOW THE STATIONARY BOUNDARY OVER THE AREA AS IT MOVES EAST-SOUTHEAST. VARIOUS SHORT TERM MODELS FORECAST THIS AREA OF STORMS EAST AND SOUTHEAST INTO CENTRAL ILLINOIS THIS EVENING...THEREFORE CONFIDENCE IS HIGH ENOUGH FOR LIKELY POPS. NO SEVERE IS EXPECTED WITH THESE STORMS...BUT LOCALLY HEAVY RAINFALL AND DEADLY LIGHTNING WILL BE LIKELY. PCPN WILL DIMINISH TOMORROW...BUT WITH LOTS OF LOW LEVEL MOISTURE AND A STATIONARY BOUNDARY IN THE AREA...CANT RULE OUT A CHANCE OF THUNDERSTORMS SOMEWHERE TOMORROW. PCPN CHANCES WILL CONTINUE AND INCREASE INTO TOMORROW NIGHT AND TUESDAY AS ANOTHER...STRONGER FRONT PUSHES INTO AND THROUGH THE AREA. FORECAST FOR THIS FRONT APPEAR TO BE THAT IT WILL PUSH SHOULD OF THE STATE LATE TUE NIGHT AND THEN BRING DRIER AND LESS HUMID AIR INTO THE REGION FOR WEDNESDAY. APPEARS TEMPS WILL BE QUITE WARM ONE MORE DAY TOMORROW. THEN ADDITIONAL CLOUD COVER AND PCPN WILL CAUSE TEMPS TO BE SLIGHTLY COOLER FOR TUESDAY. MUCH COOLER TEMPS ARE THEN EXPECTED AFTER THE FRONT MOVES THROUGH THE AREA FOR WEDNESDAY. LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY DRY WEATHER WILL CONTINUE THROUGH THUR NIGHT AS NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA. A STRONGER SYSTEM/SHORT WAVE TROUGH WILL THEN DEVELOP AND MOVE TOWARD THE AREA FOR LATE IN THE WEEK. ECMWF IS STRONGER AND LOOKS MORE CONSISTENT FROM PREVIOUS RUNS WITH THIS NEXT SYSTEM...THAN THE GFS. LEANING TOWARD THE ECMWF MODEL GIVES A FORECAST OF PCPN CHANCES FOR FRIDAY THROUGH SATURDAY NIGHT...SOMEWHERE IN THE CWA...THEN DRY WEATHER POSSIBLE SUNDAY. STILL LOTS OF UNCERTAINTY WITH THIS PERIOD OF THE FORECAST SO WOULD NOT BE SURPRISED TO SEE CHANGES TO IT OVER THE NEXT SEVERAL DAYS. TEMPS SHOULD BE COOLER THAN LAST WEEK GIVEN THE NORTHWEST FLOW AND WENT COOLER THAN GUIDANCE FOR SAT AND SUNDAY. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
700 PM CDT SUN JUL 21 2013 .DISCUSSION... ISSUED 239 PM CDT SUN JUL 21 2013 MAIN CONCERNS THIS PACKAGE WILL CONTINUE TO BE PCPN CHANCES FOR THE SHORT TERM AND THEN PCPN CHANCES AGAIN AT THE END OF THE WEEK AND INTO THE WEEKEND...IN THE LONG TERM PERIOD. MODELS SHOW GOOD AGREEMENT WITH KEEPING THE MID LEVEL NORTHWEST FLOW IN PLACE...WITH A RIDGE BUILDING OUT OVER THE ROCKIE MOUNTAIN REGION...ALL THROUGH MID WEEK. THE NORTHWEST FLOW WILL ALSO CONTINUE INTO THE EXTENDED PERIOD AND MODELS LOOK OK HERE TOO UNTIL LATE IN THE WEEK AND THE WEEKEND. ECMWF APPEARS TO BE STRONGER WITH A MID LEVEL SYSTEM COMING DOWN INTO THE AREA DURING THE END OF THE PERIOD. SHORT TERM...TONIGHT THROUGH WEDNESDAY FRONTAL SYSTEM OVER THE AREA THIS AFTERNOON WILL GRADUALLY WASHOUT TONIGHT THROUGH TOMORROW AS A STRONGER WEATHER SYSTEM DEVELOPS OUT IN THE PLAINS. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS THE ENTIRE CWA THIS EVENING AND THEN IN THE EAST AFTER MIDNIGHT...WITH CHANCES BACK TO THE WEST. LIGHT SHOWERS ARE ONGOING BUT REMNANTS OF AN MCS IN IOWA HAVE CONTINUED TO GET STRONGER IN SOUTH CENTRAL IOWA AND WILL MOVE EAST-SOUTHEAST INTO THE CWA THIS EVENING AND THROUGH TONIGHT. BELIEVE THIS LINE/COMPLEX OF STORMS WILL FOLLOW THE STATIONARY BOUNDARY OVER THE AREA AS IT MOVES EAST-SOUTHEAST. VARIOUS SHORT TERM MODELS FORECAST THIS AREA OF STORMS EAST AND SOUTHEAST INTO CENTRAL ILLINOIS THIS EVENING...THEREFORE CONFIDENCE IS HIGH ENOUGH FOR LIKELY POPS. NO SEVERE IS EXPECTED WITH THESE STORMS...BUT LOCALLY HEAVY RAINFALL AND DEADLY LIGHTNING WILL BE LIKELY. PCPN WILL DIMINISH TOMORROW...BUT WITH LOTS OF LOW LEVEL MOISTURE AND A STATIONARY BOUNDARY IN THE AREA...CANT RULE OUT A CHANCE OF THUNDERSTORMS SOMEWHERE TOMORROW. PCPN CHANCES WILL CONTINUE AND INCREASE INTO TOMORROW NIGHT AND TUESDAY AS ANOTHER...STRONGER FRONT PUSHES INTO AND THROUGH THE AREA. FORECAST FOR THIS FRONT APPEAR TO BE THAT IT WILL PUSH SHOULD OF THE STATE LATE TUE NIGHT AND THEN BRING DRIER AND LESS HUMID AIR INTO THE REGION FOR WEDNESDAY. APPEARS TEMPS WILL BE QUITE WARM ONE MORE DAY TOMORROW. THEN ADDITIONAL CLOUD COVER AND PCPN WILL CAUSE TEMPS TO BE SLIGHTLY COOLER FOR TUESDAY. MUCH COOLER TEMPS ARE THEN EXPECTED AFTER THE FRONT MOVES THROUGH THE AREA FOR WEDNESDAY. LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY DRY WEATHER WILL CONTINUE THROUGH THUR NIGHT AS NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA. A STRONGER SYSTEM/SHORT WAVE TROUGH WILL THEN DEVELOP AND MOVE TOWARD THE AREA FOR LATE IN THE WEEK. ECMWF IS STRONGER AND LOOKS MORE CONSISTENT FROM PREVIOUS RUNS WITH THIS NEXT SYSTEM...THAN THE GFS. LEANING TOWARD THE ECMWF MODEL GIVES A FORECAST OF PCPN CHANCES FOR FRIDAY THROUGH SATURDAY NIGHT...SOMEWHERE IN THE CWA...THEN DRY WEATHER POSSIBLE SUNDAY. STILL LOTS OF UNCERTAINTY WITH THIS PERIOD OF THE FORECAST SO WOULD NOT BE SURPRISED TO SEE CHANGES TO IT OVER THE NEXT SEVERAL DAYS. TEMPS SHOULD BE COOLER THAN LAST WEEK GIVEN THE NORTHWEST FLOW AND WENT COOLER THAN GUIDANCE FOR SAT AND SUNDAY. && .AVIATION... ISSUED 700 PM CDT SUN JUL 21 2013 LEANED ON THE HRRR MODEL FOR QPF FIELDS WITH ARRIVAL OF SHOWERS AND THUNDERSTORMS FROM WEST TO EAST DURING THIS EVENING AND DIMINISHING OVERNIGHT. HAVE MVFR CEILINGS POSSIBLE TONIGHT WITH PRECIPITATION ALONG WITH VSBYS RESTRICTED DOWN TO 1.5-3 MILES IN HEAVIER RAIN SHOWERS. SHOWERS AND A FEW THUNDERSTORMS ARE WEST OF I-55 AND TO SPREAD EAST TO DEC AND CMI IN THE NEXT FEW HOURS...THEN DIMINISH FROM WEST TO EAST FROM 05Z-08Z. SOME FOG POSSIBLE OVERNIGHT INTO MON MORNING WITH VSBYS 2-4 MILES AND THEN LIFTING TO LIGHT FOG/HAZE OF 4-6 MILES BETWEEN 14-15Z AS MVFR CEILINGS LIFT TO VFR LATER MON MORNING. SOUTH WINDS TO STAY FAIRLY LIGHT FROM 4-8 KTS THIS EVENING AND LIGHT AND VARIABLE OVERNIGHT AND SW 4-7 KTS MONDAY. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
113 PM CDT SAT JUL 20 2013 .UPDATE... ISSUED AT 1253 PM CDT SAT JUL 20 2013 OUTFLOW BOUNDARY FROM CONVECTION ACROSS NORTHEAST KANSAS HAS MOVED INTO AND ACROSS EASTERN SECTION OF CWA...AND IS SPARKING TSRA ACROSS PORTIONS OF THE EASTERN FLINT HILLS...AS BOUNDARY ENCOUNTERS GREATER THETAE. FLOW ALOFT IS VERY WEAK...THUS HEALTHY CAPE WILL BE THE ONLY DRIVER FOR STORM INTENSITY. RUC/HRRR BOTH INDICATE AN INCREASE IN ISOLD-WDLY SCT CONVECTION THIS AFTERNOON INTO EARLY EVENING...THUS WILL UPDATE HOURLY POPS TO ACCOUNT. ALSO WILL ADJUST HOURLY TEMPERATURES AND MAX TEMPERATURES IN EXTREME SOUTHEAST CWA...WHERE THINGS ARE WARMING MORE THAN ANTICIPATED. NO OTHER CHANGES ATTM. SF && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 344 AM CDT SAT JUL 20 2013 TODAY-TONIGHT: LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY. WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING. CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE AREA. SUN-MON: BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT. THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS. -HOWERTON .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 344 AM CDT SAT JUL 20 2013 AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON TIMING. -HOWERTON && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1253 PM CDT SAT JUL 20 2013 MAIN CONCERN FOR THE TAF PERIOD WILL BE PERIODS OF ISOLD-SCATTERED CONVECTION. FORECAST SOUNDINGS INDICATE CONVECTIVE TEMPERATURES WILL BE REACHED IN THE NEXT HOUR OR TWO...AND WITH SUFFICIENT MID-LEVEL MOISTURE...ALL TAF SITES SHOULD BEGIN TO SEE TCU/CB DEVELOPMENT BY 20 UTC. COVERAGE WILL BE LOCALLY DEPENDENT...BUT STARTED WITH SCT COVERAGE AND INCREASED TO BKN BY 22-23 UTC. CONFIDENCE OF TSRA OCCURRING AT ANY PARTICULAR TAF SITE IS LOW...THOUGH GREATEST CHANCES LIKELY AT KICT...KSLN...KCNU AND KHUT DUE TO THEIR PROXIMITY TO OUTFLOW BOUNDARY THAT HAS MOVED INTO CWA AND IS STALLING. GIVEN CONVECTION MAINLY WILL BE DIURNALLY DRIVEN...EXPECTED ANY STORMS THAT FIRE THIS AFTERNOON TO DISSIPATE IN THE 03-04 UTC TIMEFRAME. ANOTHER ROUND OF CONVECTION WILL BE POSSIBLE AFT 06 UTC...WITH ENHANCED/FOCUSED ISENTROPIC LIFT THAT WILL BE ENHANCED BY RRQ OF UPPER JET. REINTRODUCED CONVECTION IN 07-09 UTC TIMEFRAME AS A RESULT. ISENTROPIC FIELDS LINGER CONVECTION AND CONVECTIVE DEBRIS INTO SUNDAY MORNING. FORECAST SOUNDINGS PLACING TSRA BASES IN THE 6-8K AGL RANGE. SF && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 96 72 93 73 / 20 20 20 20 HUTCHINSON 95 70 94 71 / 20 20 20 20 NEWTON 93 70 92 70 / 20 30 30 20 ELDORADO 94 71 92 70 / 20 20 30 30 WINFIELD-KWLD 96 73 93 74 / 20 20 20 20 RUSSELL 94 67 98 68 / 30 30 20 20 GREAT BEND 94 66 97 68 / 20 20 20 20 SALINA 95 70 94 71 / 30 40 40 30 MCPHERSON 95 70 94 70 / 30 30 30 20 COFFEYVILLE 97 72 94 72 / 20 20 20 40 CHANUTE 94 71 92 71 / 20 30 30 40 IOLA 93 71 91 71 / 30 30 40 40 PARSONS-KPPF 96 72 93 71 / 20 20 30 40 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1250 PM CDT SAT JUL 20 2013 ...UPDATE TO AVIATION... .UPDATE... ISSUED AT 1144 AM CDT SAT JUL 20 2013 WEAK ISENTROPIC LIFT CONTINUES JUST NORTH OF THE FRONTAL BOUNDARY STRETCHED FROM SALINA TO MANHATTAN...TO OSKALOOSA IN JEFFERSON COUNTY. ALSO OBSERVING TWO OUTFLOW BOUNDARIES MOVING THROUGH SOUTHEAST NEBRASKA INTO MARSHALL AND WASHINGTON COUNTIES WHERE THE ONGOING SHOWERS AND THUNDERSTORMS ARE BEING ABLE TO REDEVELOP AND MAINTAIN THEMSELVES. CHANGES MADE TO THE CURRENT FORECAST INCLUDED ADDING PRECIPITATION CHANCES OVER MUCH OF NORTH CENTRAL AND NORTHEAST KANSAS THROUGH THE AFTERNOON. ALSO ADJUST TEMPERATURES DOWN SLIGHTLY OVER NORTH CENTRAL/NORTH EAST AREAS WHERE CLOUD COVER AND RAIN PERSISTS. WILL CONTINUE TO MONITOR FORECAST AS AREAS OF ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON ARE DEPENDENT ON LOCATION OF THE FRONT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT SAT JUL 20 2013 TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES. THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST CENTRAL KS. MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO 20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40 TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER SIZE HAIL AND 58 MPH WINDS GUSTS. THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE MORNING HOURS OF SUNDAY. BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA. HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT INDICES TO RISE INTO THE UPPER 90S. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT JUL 20 2013 THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY. ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1238 PM CDT SAT JUL 20 2013 VFR CONDITIONS WILL BE THE PREVAILING CATEGORY AT KTOP/KFOE/KMHK. CURRENTLY TRACKING A STATIONARY FRONT POSITIONED JUST NORTH OF THE TERMINALS AT 18Z. SCATTERED TSRA IS POSSIBLE ALONG THIS BOUNDARY AND WITH SOME UNCERTAINTY AS TO WHERE BOUNDARY WILL INITIATE STORMS DECIDED TO INSERT VCTS AT SITES AFT 21Z. CONFIDENCE DECREASES IN PRECIPITATION IMPACTING TERMINALS OVERNIGHT AS ANOTHER WAVE SHIFTS SOUTHEAST INTO NORTHEAST KANSAS. SHOULD SEE MOSTLY RAIN SHOWERS WITH THUNDERSTORMS EMBEDDED AFT 07Z AT KMHK AND 08Z AT KTOP/KFOE. EXACT TIMING OF THESE STORMS MAY NEED TO BE REFINED AS THEY EVOLVE OVER SOUTHERN NEBRASKA. STORMS WILL BE ELEVATED WITH PERHAPS A BRIEF PERIOD OF MVFR UNDERNEATH ANY HEAVIER THUNDERSTORM. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BOWEN SHORT TERM...GARGAN LONG TERM...63 AVIATION...BOWEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1158 AM CDT SAT JUL 20 2013 .UPDATE... ISSUED AT 1144 AM CDT SAT JUL 20 2013 WEAK ISENTROPIC LIFT CONTINUES JUST NORTH OF THE FRONTAL BOUNDARY STRETCHED FROM SALINA TO MANHATTAN...TO OSKALOOSA IN JEFFERSON COUNTY. ALSO OBSERVING TWO OUTFLOW BOUNDARIES MOVING THROUGH SOUTHEAST NEBRASKA INTO MARSHALL AND WASHINGTON COUNTIES WHERE THE ONGOING SHOWERS AND THUNDERSTORMS ARE BEING ABLE TO REDEVELOP AND MAINTAIN THEMSELVES. CHANGES MADE TO THE CURRENT FORECAST INCLUDED ADDING PRECIPITATION CHANCES OVER MUCH OF NORTH CENTRAL AND NORTHEAST KANSAS THROUGH THE AFTERNOON. ALSO ADJUST TEMPERATURES DOWN SLIGHTLY OVER NORTH CENTRAL/NORTH EAST AREAS WHERE CLOUD COVER AND RAIN PERSISTS. WILL CONTINUE TO MONITOR FORECAST AS AREAS OF ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON ARE DEPENDENT ON LOCATION OF THE FRONT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT SAT JUL 20 2013 TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES. THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST CENTRAL KS. MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO 20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40 TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER SIZE HAIL AND 58 MPH WINDS GUSTS. THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE MORNING HOURS OF SUNDAY. BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA. HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT INDICES TO RISE INTO THE UPPER 90S. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT JUL 20 2013 THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY. ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 602 AM CDT SAT JUL 20 2013 ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS THE TAF SITES THROUGH 15Z. OTHERWISE...EXPECT VFR CONDITIONS FOR THE LATE MORNING AND EARLY AFTERNOON. THERE WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS LATE THIS AFTERNOON THROUGH THE MID EVENING HOURS. LATE IN THE TAF PERIOD THERE COULD BE ANOTHER CHANCE OF THUNDERSTORMS BUT DUE TO TIMING ISSUES I HAVE NOT INCLUDED A VCTS GROUP FOR STORMS THAT MAY ARRIVE AROUND SUNRISE ON SUNDAY. GARGAN && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BOWEN SHORT TERM...GARGAN LONG TERM...63 AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS WICHITA KS
1008 AM CDT SAT JUL 20 2013 .UPDATE... ISSUED AT 1001 AM CDT SAT JUL 20 2013 ISOLATED SHRA/TSRA HAVE DISSIPATED FOR THE MOST PART...THOUGH A ANOTHER POCKET BUMBLING UP ACROSS THE NORTHEAST FRINGES OF FLINT HILLS. TRENDED POPS DOWN...AND TRIED TO ACCOUNT FOR ADVECTION AS WELL. HOURLY TEMPERATURE TRENDS ALSO ON TRACK MORE OR LESS...BUT HAD TO ADJUST DEWPOINTS SLIGHTLY UP IN SOME LOCATIONS AND DOWN IN OTHERS. OTHERWISE MAX TEMP AND OTHER SENSIBLE WEATHER FORECASTS LOOK ON TRACK. SF && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 344 AM CDT SAT JUL 20 2013 TODAY-TONIGHT: LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY. WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING. CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE AREA. SUN-MON: BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT. THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS. -HOWERTON .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 344 AM CDT SAT JUL 20 2013 AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON TIMING. -HOWERTON && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 628 AM CDT SAT JUL 20 2013 ISOLATED SHOWERS WERE ONGOING ACROSS MAINLY CENTRAL KANSAS IMPACTING KRSL AND KSLN. THIS ACTIVTY IS EXPECTED TO DRIFT NORTH AND DIMINISH BY AROUND 14Z. WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO REDEVELOP ACROSS THE AREA THIS AFTERNOON AND FESTER INTO THE OVERNIGHT HOURS. TRANSIENT MVFR WILL REMAIN POSSIBLE UNDER THE HEAVIER ACTIVITY WHILE VFR PREVAILS ACROSS THE FORECAST AREA. LIGHT AND VARIABLE WINDS WILL BECOME SOUTH TO SOUTHEAST BY MID-MORNING AT SPEEDS AROUND 15 MPH ANTICIPATED. MWM && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 96 72 93 73 / 20 20 20 20 HUTCHINSON 95 70 94 71 / 20 20 20 20 NEWTON 93 70 92 70 / 20 30 30 20 ELDORADO 94 71 92 70 / 20 20 30 30 WINFIELD-KWLD 96 73 93 74 / 20 20 20 20 RUSSELL 94 67 98 68 / 30 30 20 20 GREAT BEND 94 66 97 68 / 20 20 20 20 SALINA 95 70 94 71 / 30 40 40 30 MCPHERSON 95 70 94 70 / 30 30 30 20 COFFEYVILLE 97 72 94 72 / 20 20 20 40 CHANUTE 94 71 92 71 / 20 30 30 40 IOLA 93 71 91 71 / 30 30 40 40 PARSONS-KPPF 96 72 93 71 / 20 20 30 40 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
631 AM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 344 AM CDT SAT JUL 20 2013 TODAY-TONIGHT: LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY. WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING. CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE AREA. SUN-MON: BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT. THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS. -HOWERTON .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 344 AM CDT SAT JUL 20 2013 AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON TIMING. -HOWERTON && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 628 AM CDT SAT JUL 20 2013 ISOLATED SHOWERS WERE ONGOING ACROSS MAINLY CENTRAL KANSAS IMPACTING KRSL AND KSLN. THIS ACTIVTY IS EXPECTED TO DRIFT NORTH AND DIMINISH BY AROUND 14Z. WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO REDEVELOP ACROSS THE AREA THIS AFTERNOON AND FESTER INTO THE OVERNIGHT HOURS. TRANSIENT MVFR WILL REMAIN POSSIBLE UNDER THE HEAVIER ACTIVITY WHILE VFR PREVAILS ACROSS THE FORECAST AREA. LIGHT AND VARIABLE WINDS WILL BECOME SOUTH TO SOUTHEAST BY MID-MORNING AT SPEEDS AROUND 15 MPH ANTICIPATED. MWM && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 96 72 93 73 / 20 20 20 20 HUTCHINSON 95 70 94 71 / 20 20 20 20 NEWTON 93 70 92 70 / 20 30 30 20 ELDORADO 94 71 92 70 / 20 20 30 30 WINFIELD-KWLD 96 73 93 74 / 20 20 20 20 RUSSELL 94 67 98 68 / 30 30 20 20 GREAT BEND 94 66 97 68 / 20 20 20 20 SALINA 95 70 94 71 / 30 40 40 30 MCPHERSON 95 70 94 70 / 30 30 30 20 COFFEYVILLE 97 72 94 72 / 20 20 20 40 CHANUTE 94 71 92 71 / 20 30 30 40 IOLA 93 71 91 71 / 30 30 40 40 PARSONS-KPPF 96 72 93 71 / 20 20 30 40 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
606 AM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT SAT JUL 20 2013 TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES. THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST CENTRAL KS. MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO 20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40 TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER SIZE HAIL AND 58 MPH WINDS GUSTS. THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE MORNING HOURS OF SUNDAY. BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA. HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT INDICES TO RISE INTO THE UPPER 90S. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT JUL 20 2013 THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY. ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 602 AM CDT SAT JUL 20 2013 ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS THE TAF SITES THROUGH 15Z. OTHERWISE...EXPECT VFR CONDITIONS FOR THE LATE MORNING AND EARLY AFTERNOON. THERE WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS LATE THIS AFTERNOON THROUGH THE MID EVENING HOURS. LATE IN THE TAF PERIOD THERE COULD BE ANOTHER CHANCE OF THUNDERSTORMS BUT DUE TO TIMING ISSUES I HAVE NOT INCLUDED A VCTS GROUP FOR STORMS THAT MAY ARRIVE AROUND SUNRISE ON SUNDAY. GARGAN && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GARGAN LONG TERM...63 AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
352 AM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT SAT JUL 20 2013 TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES. THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST CENTRAL KS. MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO 20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40 TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER SIZE HAIL AND 58 MPH WINDS GUSTS. THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE MORNING HOURS OF SUNDAY. BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA. HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT INDICES TO RISE INTO THE UPPER 90S. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT JUL 20 2013 THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY. ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1154 PM CDT FRI JUL 19 2013 FOR THE 06Z TAFS...THE SCATTERED SHOWERS AND THUNDERSTORMS FROM THIS EVENING WILL CONTINUE TO WEAKEN AND DIMINISH INTO THE EARLY OVERNIGHT HOURS. WINDS OVERNIGHT WILL BE CALM...BECOMING LIGHT OUT OF THE SOUTHEAST THROUGH THE DAY ON SATURDAY. ADDITIONAL CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS EXISTS ACROSS THE REGION SATURDAY NIGHT. THERE IS STILL UNCERTAINTY IN THE EXACT TIMING AND LOCATION OF ANY PRECIPITATION...SO HAVE JUST ADDED THE MENTION OF VCTS ATTM AND WILL CONTINUE TO ADJUST WITH FUTURE UPDATES. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GARGAN LONG TERM...63 AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS WICHITA KS
350 AM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 344 AM CDT SAT JUL 20 2013 TODAY-TONIGHT: LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY. WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING. CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE AREA. SUN-MON: BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT. THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS. -HOWERTON .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 344 AM CDT SAT JUL 20 2013 AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON TIMING. -HOWERTON && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1139 PM CDT FRI JUL 19 2013 SCATTERED SHOWERS AND THUNDERSTORMS ARE DIMINISHING AS WE APPROACH 06Z. EXPECT ACTIVITY TO WANE THROUGH 12Z AND INTO THE MORNING/EARLY AFTERNOON HOURS BEFORE ANOTHER ROUND OF SHOWER AND THUNDERSTORM ACTIVITY IS POSSIBLE IN THE AFTERNOON. CANNOT RULE OUT SOMETHING IN THE MORNING...BUT DO NOT HAVE IT REPRESENTED IN THE TAF FORECAST AT THIS TIME. WINDS BEHIND THE CONVECTION ARE LIGHT AND OUT OF THE EAST. WINDS WILL GRADUALLY BECOME SOUTHERLY BY MORNING ACROSS THE AREA AND INCREASE SLIGHTLY DURING THE DAY. VFR CONDITIONS ARE EXPECTED TO PREVAIL. BILLINGS && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 96 72 93 73 / 20 20 20 20 HUTCHINSON 95 70 94 71 / 20 20 20 20 NEWTON 93 70 92 70 / 20 30 30 20 ELDORADO 94 71 92 70 / 20 20 30 30 WINFIELD-KWLD 96 73 93 74 / 20 20 20 20 RUSSELL 94 67 98 68 / 30 30 20 20 GREAT BEND 94 66 97 68 / 20 20 20 20 SALINA 95 70 94 71 / 30 40 40 30 MCPHERSON 95 70 94 70 / 30 30 30 20 COFFEYVILLE 97 72 94 72 / 20 20 20 40 CHANUTE 94 71 92 71 / 20 30 30 40 IOLA 93 71 91 71 / 30 30 40 40 PARSONS-KPPF 96 72 93 71 / 20 20 30 40 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS JACKSON KY
933 PM EDT SUN JUL 21 2013 .UPDATE... ISSUED AT 932 PM EDT SUN JUL 21 2013 TRAINING STORMS WERE STILL ONGOING OVER THE NORTHERN SECTION OF THE CWA AS WAS DISCUSSED IN THE PREVIOUS UPDATE. WENT AHEAD AND EXTENDED SCT POPS FOR THE NEXT COUPLE OF HOURS...MAINLY ALONG THE MOUNTAIN PARKWAY WHERE MAIN SHOWER ACTIVITY HAS BEEN LOCATED. LATEST RADAR TRENDS ARE SHOWING BEST SHOWER ACTIVITY DIMINISHING...BUT LOW END CHANCE POPS ARE STILL WARRANTED FOR ONGOING ACTIVITY AND POTENTIAL REDEVELOPMENT. EXCESS MOISTURE ACROSS THE NORTH AND EAST HAS LED TO FOG DEVELOPMENT AT THE NWS OFFICE. AS RAIN CONTINUES TO DIMINISH...EXPECT FOG TO PREVAIL THROUGH MUCH OF THE NIGHT BEFORE NEXT AREA OF WIDESPREAD SHOWERS AND THUNDERSTORMS MOVES IN BY EARLY MORNING. MADE THIS UPDATE TO THE WEATHER GRIDS AS WELL...ADDING FOG IN FOR VALLEYS MAINLY IN THE EASTERN CWA. UPDATE ISSUED AT 544 PM EDT SUN JUL 21 2013 A CONTINUED LINE OF SCT TRAINING STORMS EXTENDS ACROSS THE NORTHERN HALF OF THE CWA ALONG SOME WEAK HORIZONTAL BOUNDARY. PREVIOUS FORECAST HAD SHOWERS ENDING OVER THE NW...BUT SO LONG AS THIS BOUNDARY REMAINS IN PLACE...EXPECT ISOLATED TO SCT SHOWERS AND THUNDERSTORMS TO CONTINUE OVER THIS AREA FOR THE NEXT COUPLE HOURS. ALSO ADDED IN SOME ISOLATED POPS FOR SOME AREAS OVERNIGHT...MAINLY BEFORE MIDNIGHT...BASED ON LATEST HI RES MODEL RUNS AND CURRENT FORECAST TRENDS. ADDED CURRENT OBSERVATIONS INTO ONGOING FORECAST AS WELL. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 325 PM EDT SUN JUL 21 2013 MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST. GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING UP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 325 PM EDT SUN JUL 21 2013 THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED. HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG. IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS. SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL. A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE COOLER AIR REMAINS TO START THE NEW WORK WEEK. THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 754 PM EDT SUN JUL 21 2013 VERY TRICKY AVIATION FORECAST...WITH MANY THINGS TO CONSIDER OVER THE NEXT 24 HOURS. A FRONTAL BOUNDARY DRAPED ACROSS THE AREA WILL CONTINUE TO PRODUCE TRAINING SHOWERS AND THUNDERSTORMS ACROSS THE NORTHERN HALF OF THE CWA...INCLUDING KJKL. KJKL IS CURRENTLY EXPERIENCING HEAVY RAIN...BR...AND LIFR VIS AT TIMES. EXPECT THESE SHOWERS AND RESULTING CONDITIONS TO CONTINUE ALONG THE BOUNDARY OVER THE NEXT COUPLE OF HOURS. ELSEWHERE...SHOWER ACTIVITY AND BKN CLOUDS ARE TRYING TO CLEAR...BUT LEFT MVFR BKN IN THE TAFS FOR KLOZ AND KSME SINCE SOME HEAVIER BKN BANDS OF CLOUDS ARE STILL POSSIBLE ACCORDING TO LATEST SATELLITE. FOR THE REST OF THE NIGHT...ANY LINGERING SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF BY LATE TONIGHT...BUT WITH CLEARING COMES THE POSSIBILITY FOR FOG TO DEVELOP. TRIED TO BE OPTIMISTIC ON VALLEY FOG REACHING TAF SITES...ONLY GOING MVFR VIS...BUT MAY NEED TO ADJUST AS FOG DEVELOPS. THE NEXT CHANCE FOR WIDESPREAD RAIN AND THUNDERSTORMS WILL MOVE IN BY DAWN AND CONTINUE THROUGHOUT THE DAY AT ALL TAF SITES. STILL SOMEWHAT UNCERTAIN ON VIS AND CIG RESTRICTIONS DURING THIS TIME WITH ONGOING CONVECTIVE ACTIVITY...BUT TRIED TO SHOW GENERAL TREND DOWNWARDS. VIS WILL BE RESTRICTED FURTHER IF A HEAVY RAIN SHOWER PASSES OVER TAF SITE. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...JMW SHORT TERM...KAS LONG TERM...GREIF AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
754 PM EDT SUN JUL 21 2013 .UPDATE... ISSUED AT 544 PM EDT SUN JUL 21 2013 A CONTINUED LINE OF SCT TRAINING STORMS EXTENDS ACROSS THE NORTHERN HALF OF THE CWA ALONG SOME WEAK HORIZONTAL BOUNDARY. PREVIOUS FORECAST HAD SHOWERS ENDING OVER THE NW...BUT SO LONG AS THIS BOUNDARY REMAINS IN PLACE...EXPECT ISOLATED TO SCT SHOWERS AND THUNDERSTORMS TO CONTINUE OVER THIS AREA FOR THE NEXT COUPLE HOURS. ALSO ADDED IN SOME ISOLATED POPS FOR SOME AREAS OVERNIGHT...MAINLY BEFORE MIDNIGHT...BASED ON LATEST HI RES MODEL RUNS AND CURRENT FORECAST TRENDS. ADDED CURRENT OBSERVATIONS INTO ONGOING FORECAST AS WELL. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 325 PM EDT SUN JUL 21 2013 MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST. GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING UP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 325 PM EDT SUN JUL 21 2013 THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED. HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG. IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS. SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL. A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE COOLER AIR REMAINS TO START THE NEW WORK WEEK. THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 754 PM EDT SUN JUL 21 2013 VERY TRICKY AVIATION FORECAST...WITH MANY THINGS TO CONSIDER OVER THE NEXT 24 HOURS. A FRONTAL BOUNDARY DRAPED ACROSS THE AREA WILL CONTINUE TO PRODUCE TRAINING SHOWERS AND THUNDERSTORMS ACROSS THE NORTHERN HALF OF THE CWA...INCLUDING KJKL. KJKL IS CURRENTLY EXPERIENCING HEAVY RAIN...BR...AND LIFR VIS AT TIMES. EXPECT THESE SHOWERS AND RESULTING CONDITIONS TO CONTINUE ALONG THE BOUNDARY OVER THE NEXT COUPLE OF HOURS. ELSEWHERE...SHOWER ACTIVITY AND BKN CLOUDS ARE TRYING TO CLEAR...BUT LEFT MVFR BKN IN THE TAFS FOR KLOZ AND KSME SINCE SOME HEAVIER BKN BANDS OF CLOUDS ARE STILL POSSIBLE ACCORDING TO LATEST SATELLITE. FOR THE REST OF THE NIGHT...ANY LINGERING SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF BY LATE TONIGHT...BUT WITH CLEARING COMES THE POSSIBILITY FOR FOG TO DEVELOP. TRIED TO BE OPTIMISTIC ON VALLEY FOG REACHING TAF SITES...ONLY GOING MVFR VIS...BUT MAY NEED TO ADJUST AS FOG DEVELOPS. THE NEXT CHANCE FOR WIDESPREAD RAIN AND THUNDERSTORMS WILL MOVE IN BY DAWN AND CONTINUE THROUGHOUT THE DAY AT ALL TAF SITES. STILL SOMEWHAT UNCERTAIN ON VIS AND CIG RESTRICTIONS DURING THIS TIME WITH ONGOING CONVECTIVE ACTIVITY...BUT TRIED TO SHOW GENERAL TREND DOWNWARDS. VIS WILL BE RESTRICTED FURTHER IF A HEAVY RAIN SHOWER PASSES OVER TAF SITE. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...JMW SHORT TERM...KAS LONG TERM...GREIF AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
528 PM EDT SAT JUL 20 2013 .UPDATE... ISSUED AT 527 PM EDT SAT JUL 20 2013 BASED ON CURRENT RADAR TRENDS...DIDN/T FEEL CONFIDENT IN NO POPS ACROSS THE AREA THIS AFTERNOON/EVENING. WENT AHEAD AND ADDED IN SOME SLIGHT CHANCES ALONG THE NORTHERN AND SOUTHEASTERN SECTIONS OF THE CWA THROUGH THIS AFTERNOON IN CASE SOME SHORT LIVED CONVECTION DEVELOPS. THEN HAVE ISOLATED CHANCES TAPERING OFF ACROSS THE SOUTHEAST THIS EVENING AS BEST INSTABILITY BECOMES FOCUSED OVER THE NORTHERN CWA WITH AN IMPOSING COLD FRONT AND AREA OF CONVECTION MOVING INTO THE REGION. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 325 PM EDT SAT JUL 20 2013 CONTINUING TO WATCH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DROPPING SOUTHWARD ACROSS THE OHIO RIVER VALLEY. A GAP IN THE LINE HAS OPENED UP JUST TO OUR NORTH. WHILE SHOWERS AND STORMS ARE STILL POSSIBLE THIS EVENING INTO TONIGHT...EVERY HRRR RUN OVER THE PAST SEVERAL HOURS CONTINUES TO BACK OFF ON OVERALL COVERAGE ACROSS EASTERN KENTUCKY THIS EVENING...WITH EVERYTHING FADING AWAY AROUND SUNSET. THUS...HAVE DECREASED POPS INTO THIS EVENING AND THE OVERNIGHT HOURS. THIS TREND MAY HAVE TO BE CONTINUED ON THE EVENING SHIFT IF THE TRENDS CONTINUE THE WAY THEY ARE HEADING. REGARDLESS...THE PROSPECTS FOR WIDESPREAD SHOWERS AND THUNDERSTORMS IS DRASTICALLY LESS NOW. WILL MAINTAIN LOW 20-30 POPS THROUGH THE OVERNIGHT HOURS. WITH THE BOUNDARY WASHED OUT OVER THE AREA TOMORROW...DAYTIME HEATING SHOULD ALLOW FOR QUICK REDEVELOPMENT AFTER SUNRISE. COVERAGE SHOULD BE DECENT TOMORROW...SO OPTED TO STAY WITH OUR 60-70 POPS. THERE IS SOME QUESTION AS TO HOW MUCH ACTIVITY WILL THEN LINGER INTO TOMORROW NIGHT AS THE QUASI BOUNDARY MAY SHIFT BACK TO THE NORTH. LACK OF OVERNIGHT INSTABILITY MAY KEEP THINGS FAIRLY LOW KEY FOR MUCH OF THE NIGHT. THERE IS A SHORTWAVE TROUGH PUSHING ACROSS THE AREA LATE IN THE NIGHT THAT COULD ACT TO FIRE OFF SOME SHOWERS AND THUNDERSTORMS...SO WILL INCREASE POPS THROUGH THE NIGHT. TEMPERATURES ON SUNDAY SHOULD BE SLIGHTLY LOWER WITH THE INCREASED CLOUD COVER AND PRECIPITATION. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 325 PM EDT SAT JUL 20 2013 THE MODELS BASICALLY AGREE ON THE GENERAL MID LEVEL PATTERN THROUGH THE BULK OF THE EXTENDED FORECAST. A TROUGH WILL DEVELOP THROUGH THE OHIO VALLEY INITIALLY AS ENERGY FROM THE NORTHERN PLAINS POOLS OVER THE REGION. THIS TROUGH EVOLVES GRADUALLY AS A COUPLE OF CYCLES OF WAVES MOVE THROUGH THE OHIO VALLEY...EACH DEPICTED SLIGHTLY DIFFERENT BY THE MODELS. THIS SEMI-STATIONARY TROUGH BOTTOMS OUT ON THURSDAY PER A CONSENSUS OF SOLUTIONS. EACH MODEL HAS ENOUGH OF A DIFFERENT HANDLING OF THE INDIVIDUAL WAVES THAT A BLENDED APPROACH IS PREFERRED FOR EXTENDED FORECASTING PURPOSES. IT DOES LOOK LIKE HEIGHTS WILL RISE A BIT ON FRIDAY AS THE CORE OF THE TROUGH SHIFTS TEMPORARILY EAST BUT THE ECMWF IS MOST AGGRESSIVE IN TAKING ANOTHER DECENT WAVE FROM THE PLAINS EAST INTO THE OHIO VALLEY FOR THE WEEKEND LIKELY RESTORING THE TROUGH FOR THE OHIO VALLEY. THE GFS HAS A VERSION OF THIS THAT ALSO LOWERS HEIGHTS OVER THE OHIO VALLEY ON SATURDAY...BUT DOES SO BY RELYING ON WAVES FURTHER NORTH THAN THE ECMWF...MAINLY MOVING THEM THROUGH THE GREAT LAKES. AGAIN HERE... WILL FAVOR A CONSENSUS SOLUTION FOR WEATHER DETAILS. SENSIBLE WEATHER WILL FEATURE A VERY UNSETTLED SITUATION TO START THE EXTENDED AS MID LEVEL WAVES ACTIVATE SHOWERS AND THUNDERSTORMS ALONG AND SOUTH OF A FRONTAL BOUNDARY RUNNING JUST NORTH OF THE OHIO RIVER. THERE WILL BE PLENTY OF HIGH PW AIR IN PLACE TO SUPPORT THE STORMS AND THUS A HEAVY RAIN POTENTIAL WILL EXIST THROUGH THE DAY...MONDAY. THE NEXT SFC BOUNDARY WILL APPROACH THE AREA ON TUESDAY CONTINUING OUR CHANCES OF SHOWERS AND THUNDERSTORMS. THIS CONVECTION IS EXPECTED TO LINGER INTO THE NIGHT WHEN THE BOUNDARY DROPS THROUGH THE CWA IN THE FORM OF A COLD FRONT. FOR THURSDAY AND FRIDAY...ANY CONVECTION SHOULD BE AT A MINIMUM IN THE WAKE OF THE SFC FRONT AND SLIGHTLY HIGHER HEIGHTS ALOFT. HOWEVER...THE NEXT SFC SYSTEM LOOKS TO BRING A RENEWED CHANCE OF CONVECTION TO THE AREA ON SATURDAY...SPURRED ON BY FALLING HEIGHTS AND MORE INBOUND MID-LEVEL ENERGY. THE CR GRID LOAD CAME IN PRETTY GOOD CONSIDERING THE SMALLER SCALE DIFFERENCES AMONG THE MODELS WITH RESPECT TO WEATHER DETAILS THROUGH THE EXTENDED. DID NUDGE DOWN POPS A BIT LATE IN THE FORECAST...MORE TOWARD THE OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY NIGHT TO BETTER EMPHASIZE RIDGE AND VALLEY TEMPERATURE DIFFERENCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 123 PM EDT SAT JUL 20 2013 A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL CONTINUE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...KAS LONG TERM...GREIF AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
325 PM EDT SAT JUL 20 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 325 PM EDT SAT JUL 20 2013 CONTINUING TO WATCH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DROPPING SOUTHWARD ACROSS THE OHIO RIVER VALLEY. A GAP IN THE LINE HAS OPENED UP JUST TO OUR NORTH. WHILE SHOWERS AND STORMS ARE STILL POSSIBLE THIS EVENING INTO TONIGHT...EVERY HRRR RUN OVER THE PAST SEVERAL HOURS CONTINUES TO BACK OFF ON OVERALL COVERAGE ACROSS EASTERN KENTUCKY THIS EVENING...WITH EVERYTHING FADING AWAY AROUND SUNSET. THUS...HAVE DECREASED POPS INTO THIS EVENING AND THE OVERNIGHT HOURS. THIS TREND MAY HAVE TO BE CONTINUED ON THE EVENING SHIFT IF THE TRENDS CONTINUE THE WAY THEY ARE HEADING. REGARDLESS...THE PROSPECTS FOR WIDESPREAD SHOWERS AND THUNDERSTORMS IS DRASTICALLY LESS NOW. WILL MAINTAIN LOW 20-30 POPS THROUGH THE OVERNIGHT HOURS. WITH THE BOUNDARY WASHED OUT OVER THE AREA TOMORROW...DAYTIME HEATING SHOULD ALLOW FOR QUICK REDEVELOPMENT AFTER SUNRISE. COVERAGE SHOULD BE DECENT TOMORROW...SO OPTED TO STAY WITH OUR 60-70 POPS. THERE IS SOME QUESTION AS TO HOW MUCH ACTIVITY WILL THEN LINGER INTO TOMORROW NIGHT AS THE QUASI BOUNDARY MAY SHIFT BACK TO THE NORTH. LACK OF OVERNIGHT INSTABILITY MAY KEEP THINGS FAIRLY LOW KEY FOR MUCH OF THE NIGHT. THERE IS A SHORTWAVE TROUGH PUSHING ACROSS THE AREA LATE IN THE NIGHT THAT COULD ACT TO FIRE OFF SOME SHOWERS AND THUNDERSTORMS...SO WILL INCREASE POPS THROUGH THE NIGHT. TEMPERATURES ON SUNDAY SHOULD BE SLIGHTLY LOWER WITH THE INCREASED CLOUD COVER AND PRECIPITATION. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 325 PM EDT SAT JUL 20 2013 THE MODELS BASICALLY AGREE ON THE GENERAL MID LEVEL PATTERN THROUGH THE BULK OF THE EXTENDED FORECAST. A TROUGH WILL DEVELOP THROUGH THE OHIO VALLEY INITIALLY AS ENERGY FROM THE NORTHERN PLAINS POOLS OVER THE REGION. THIS TROUGH EVOLVES GRADUALLY AS A COUPLE OF CYCLES OF WAVES MOVE THROUGH THE OHIO VALLEY...EACH DEPICTED SLIGHTLY DIFFERENT BY THE MODELS. THIS SEMI-STATIONARY TROUGH BOTTOMS OUT ON THURSDAY PER A CONSENSUS OF SOLUTIONS. EACH MODEL HAS ENOUGH OF A DIFFERENT HANDLING OF THE INDIVIDUAL WAVES THAT A BLENDED APPROACH IS PREFERRED FOR EXTENDED FORECASTING PURPOSES. IT DOES LOOK LIKE HEIGHTS WILL RISE A BIT ON FRIDAY AS THE CORE OF THE TROUGH SHIFTS TEMPORARILY EAST BUT THE ECMWF IS MOST AGGRESSIVE IN TAKING ANOTHER DECENT WAVE FROM THE PLAINS EAST INTO THE OHIO VALLEY FOR THE WEEKEND LIKELY RESTORING THE TROUGH FOR THE OHIO VALLEY. THE GFS HAS A VERSION OF THIS THAT ALSO LOWERS HEIGHTS OVER THE OHIO VALLEY ON SATURDAY...BUT DOES SO BY RELYING ON WAVES FURTHER NORTH THAN THE ECMWF...MAINLY MOVING THEM THROUGH THE GREAT LAKES. AGAIN HERE... WILL FAVOR A CONSENSUS SOLUTION FOR WEATHER DETAILS. SENSIBLE WEATHER WILL FEATURE A VERY UNSETTLED SITUATION TO START THE EXTENDED AS MID LEVEL WAVES ACTIVATE SHOWERS AND THUNDERSTORMS ALONG AND SOUTH OF A FRONTAL BOUNDARY RUNNING JUST NORTH OF THE OHIO RIVER. THERE WILL BE PLENTY OF HIGH PW AIR IN PLACE TO SUPPORT THE STORMS AND THUS A HEAVY RAIN POTENTIAL WILL EXIST THROUGH THE DAY...MONDAY. THE NEXT SFC BOUNDARY WILL APPROACH THE AREA ON TUESDAY CONTINUING OUR CHANCES OF SHOWERS AND THUNDERSTORMS. THIS CONVECTION IS EXPECTED TO LINGER INTO THE NIGHT WHEN THE BOUNDARY DROPS THROUGH THE CWA IN THE FORM OF A COLD FRONT. FOR THURSDAY AND FRIDAY...ANY CONVECTION SHOULD BE AT A MINIMUM IN THE WAKE OF THE SFC FRONT AND SLIGHTLY HIGHER HEIGHTS ALOFT. HOWEVER...THE NEXT SFC SYSTEM LOOKS TO BRING A RENEWED CHANCE OF CONVECTION TO THE AREA ON SATURDAY...SPURRED ON BY FALLING HEIGHTS AND MORE INBOUND MID-LEVEL ENERGY. THE CR GRID LOAD CAME IN PRETTY GOOD CONSIDERING THE SMALLER SCALE DIFFERENCES AMONG THE MODELS WITH RESPECT TO WEATHER DETAILS THROUGH THE EXTENDED. DID NUDGE DOWN POPS A BIT LATE IN THE FORECAST...MORE TOWARD THE OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY NIGHT TO BETTER EMPHASIZE RIDGE AND VALLEY TEMPERATURE DIFFERENCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 123 PM EDT SAT JUL 20 2013 A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL CONTINUE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KAS LONG TERM...GREIF AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
200 PM CDT SAT JUL 20 2013 .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 200 PM CDT SAT JUL 20 2013 18Z MESOANALYSIS SHOWS A COLD FRONT EXTENDING WESTWARD ACROSS CENTRAL INDIANA TO A WEAK SURFACE LOW OVER CENTRAL ILLINOIS. A SURFACE TROUGH EXTENDS SOUTHWEST FROM THE LOW CENTER TO NEAR KFAM AND THEN BETWEEN KUNO/KPOF. DEW POINTS POOLING INTO THE LOWER AND MID 70S ALONG THE TROUGH AND COLD FRONT HAVE CONTRIBUTED TO VERY UNSTABLE CAPES LOCALLY OVER 3000 J/KG. ISOLATED STORMS HAVE POPPED UP ALONG THE SURFACE TROUGH OVER MISSOURI...WHILE LARGER CLUSTERS OF STORMS ARE EAST OF THE SURFACE LOW CENTER IN INDIANA/EAST CENTRAL IL. THROUGH THE EVENING HOURS...THE COLD FRONT IS FORECAST TO DRIFT SOUTH TO THE INTERSTATE 64 CORRIDOR WHILE THE SURFACE TROUGH REMAINS STATIONARY OVER THE MISSOURI OZARKS. THE LATEST HRRR MODEL REFLECTIVITY INDICATES THAT CLUSTERS OF STORMS /POSSIBLE MCS/ WILL PROPAGATE SOUTH ALONG THE WABASH VALLEY...REACHING THE PENNYRILE REGION OF WESTERN KY THIS EVENING. THIS SCENARIO IS SUPPORTED BY THE 12Z HIGH RES NMM. OTHER ISOLATED STORMS MAY DEVELOP EASTWARD FROM THE SURFACE TROUGH OVER MISSOURI. VERY LIMITED SHEAR MAGNITUDE WILL LIMIT SEVERE POTENTIAL TO ISOLATED PULSE EVENTS...THOUGH AN ORGANIZED COLD POOL COULD DEVELOP WITH THE WABASH VALLEY MCS. ACTIVITY WILL WEAKEN SIGNIFICANTLY BY 06Z AS THE BOUNDARY LAYER COOLS AND STABILIZES. ON SUNDAY...THE SURFACE FRONT IS FORECAST TO SLOWLY LIFT BACK NORTH AS A WARM FRONT. A MINOR 500 MB SHORTWAVE WILL MOVE EAST/SOUTHEAST ACROSS THE MISSISSIPPI VALLEY. THIS SHORTWAVE WILL HELP REJUVENATE CONVECTION ALONG AND SOUTH OF THE FRONT...ESPECIALLY DURING THE WARMER AND MORE UNSTABLE AFTERNOON HOURS. HIGH TEMPS WILL STRUGGLE TO REACH THE UPPER 80S DUE TO ABUNDANT CLOUDINESS AND CONVECTION. ON SUNDAY NIGHT...A RATHER WELL DEVELOPED 500 MB SHORTWAVE FOR MID SUMMER WILL APPROACH FROM THE CENTRAL PLAINS. THIS SHORTWAVE WILL TAP A VERY MOIST AND UNSTABLE SOUTHWEST WIND FLOW. SHOWERS AND STORMS ARE LIKELY OVERNIGHT INTO MONDAY MORNING...UNTIL THE PASSAGE OF THE SHORTWAVE. ONCE AGAIN...SEASONABLY WEAK SHEAR PROFILES WILL LIMIT THE POTENTIAL HAZARDS TO MAINLY HEAVY RAIN AND FREQUENT LIGHTNING. ON MONDAY AFTERNOON AND MONDAY NIGHT...PRECIP COVERAGE WILL GRADUALLY DECREASE WITH THE PASSAGE OF THE SHORTWAVE. 850 MB WARM ADVECTION WILL BE COUNTERED BY EXTENSIVE CLOUD COVER AND PRECIP... SO DAYTIME HIGHS ON MONDAY WILL ONLY BE NEAR SEASONAL NORMS. OVERNIGHT LOWS WILL BE NEAR SURFACE DEW POINTS IN THE LOWER 70S. .LONG TERM /TUESDAY THROUGH SATURDAY/... ISSUED AT 200 PM CDT SAT JUL 20 2013 THE MODELS ARE IN A LITTLE BETTER AGREEMENT WITH THE TIMING OF THE MID WEEK FRONT. THIS FRONT WILL PROVIDE THE FOCUS FOR THUNDERSTORMS TUESDAY THEN TAPERING OFF INTO WEDNESDAY. WEAK HIGH PRESSURE WILL DRY US OUT FOR AT LEAST THURSDAY AND FRIDAY WITH AT LEAST A CHANCE RETURNING FRIDAY NIGHT INTO SATURDAY AS YET ANOTHER COLD FRONT ENTERS THE PICTURE AT THE SAME TIME A WARM FRONT TRIES TO LIFT OUT OF THE PLAINS INTO THE REGION. THE LATEST RUNS WOULD HAVE THE COLD FRONT WINNING OUT AND SUPPRESSING THE WARM FRONT TO THE SOUTHWEST. HOWEVER...THE SIGNALS ARE VERY WEAK AND MAY FLIP FLOP WITH LATER RUNS. THIS WOULD ALSO RESULT IN A SIGNIFICANT CHANGE FOR TEMPS THIS WEEKEND. EITHER WAY ONE SYSTEM OR THE OTHER WILL PROVIDE A CHANCE FOR THUNDERSTORMS. AS FOR TEMPS FOLLOWED THE ONGOING TREND WITH THE WARMEST DAY TUESDAY THEN COOLING AND A BIT DRIER LATE IN THE WEEK. TEMPS BEGIN TO SOAR BACK TO AROUND 90 LATE IN THE WEEK AHEAD OF THE APPROACHING COLD FRONT. IF THE WEEKEND COLD FRONT MAKES IT THROUGH THE AREA WE WILL COOL BACK INTO THE 80S AGAIN HOWEVER SHOULD THE WARM FRONT OVERTAKE THE REGION WILL HAVE TO ADJUST TEMPS UP FROM CURRENT FORECAST. && .AVIATION... ISSUED AT 1226 PM CDT SAT JUL 20 2013 A WEAK COLD FRONT WAS IN THE VICINITY OF KSTL/KIND LINE AT 17Z. THIS FRONT WILL SINK SLOWLY SOUTH...POSSIBLY BRINGING ISOLATED TO SCATTERED THUNDERSTORMS TO THE TAF SITES THIS EVENING. CONVECTION SHOULD WEAKEN OR DISSIPATE WITH LOSS OF DAYTIME HEATING BY 06Z. WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT...ALLOWING SOME LIGHT FOG OR HAZE TO FORM AS SKIES BECOME MOSTLY CLEAR. MID LEVEL CLOUDS WILL INCREASE AHEAD OF AN UPPER LEVEL DISTURBANCE EARLY SUNDAY. SCATTERED SHOWERS MAY DEVELOP AFTER SUNRISE AS THE FRONT BEGINS TO MOVE BACK NORTH AS A WARM FRONT. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...MY LONG TERM...KH AVIATION...MY
AREA FORECAST DISCUSSION
NWS JACKSON KY
123 PM EDT SAT JUL 20 2013 .UPDATE... ISSUED AT 123 PM EDT SAT JUL 20 2013 WATCHING A COUPLE COMPLEXES OF SHOWERS AND THUNDERSTORMS OFF TO THE NORTH. THE FIRST ONE JUST WENT THROUGH THE INDIANAPOLIS AREA...WITH THE SECOND ONE JUST THROUGH DAYTON. THE ONE THAT CONCERNS EASTERN KENTUCKY IS THE COMPLEX IN INDIANA. BASED ON TRENDS...THIS COMPLEX SHOULD REACH NORTHERN FLEMING COUNTY AROUND 23Z. THERE WAS A WIND GUST AT THE INDIANAPOLIS AIRPORT TO 36 KNOTS...SO THERE IS SOME LOW END POTENTIAL FOR SOME STRONG WIND GUSTS AS THIS STUFF PUSHES SOUTHEAST THIS EVENING. SPC HAS ISSUED A WATCH JUST TO OUR NORTH. FORTUNATELY THE SHEAR IS VERY WEAK AND GETTING MORE WIDESPREAD DAMAGING WINDS SEEMS VERY LOW AT THIS TIME. OTHER ISOLATED SHOWERS AND EVEN A THUNDERSTORM HAVE DEVELOPED ACROSS EASTERN KENTUCKY. MOST OF THESE SHOWERS HAVE BEEN SHORT LIVED AND FEW AND FAR BETWEEN. OUTSIDE OF A SOME SPORADIC LIGHTNING OR A BRIEF PERIOD OF HEAVY RAIN...THESE SHOWERS SHOULD POSE VERY LITTLE THREAT TO THE AREA THIS AFTERNOON. UPDATE ISSUED AT 923 AM EDT SAT JUL 20 2013 BAND OF ENHANCED CU IS PUSHING SOUTHEAST...EXTENDING FROM NEAR DANVILLE TO WEST LIBERTY THIS MORNING. BASED ON INITIAL ANALYSIS THIS MORNING...THIS MAY HELP TO GENERATE SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS HEADING INTO THE AFTERNOON HOURS. HOWEVER...THIS ACTIVITY WILL LIKELY SHIFT SOUTHEAST AS WE HEAD INTO THE LATE AFTERNOON HOURS AS SUBSIDENCE AHEAD OF THE APPROACHING COLD FRONT FROM THE NORTH OVERSPREADS THE AREA. LATEST HRRR TAKES MOST OF THE DAY TO GET ANY PRECIPITATION AS FAR SOUTH AS FLEMING COUNTY (LIKELY NOT UNTIL AFTER 22 OR 23Z). THUS...GOING TO BACK OFF ON THE HIGHER PRECIPITATION CHANCES TODAY...BUT STILL CARRY SOME ISOLATED COVERAGE ACROSS THE SOUTHEAST ASSOCIATED WITH THE BAND OF ENHANCED CU AS IT DROPS SOUTHEAST. OTHERWISE...WILL GO WITH HIGHER POPS NORTH OF I-64 AFTER 22Z. SOME QUESTION AS TO HOW MUCH ACTIVITY LINGERS INTO TONIGHT AS THE FRONT WASHES OUT OVER THE AREA. WILL DROP POPS BACK FOR THE OVERNIGHT HOURS AS COVERAGE WILL LIKELY REMAIN MORE ISOLATED TO SCATTERED ALONG THE BOUNDARY SINCE IT WILL BE HARD TO SEE MUCH ORGANIZED ACTIVITY ALONG THE STALLED BOUNDARY. UPDATE WILL BE OUR SHORTLY. UPDATE ISSUED AT 705 AM EDT SAT JUL 20 2013 INGESTED THE MOST CURRENT OBSERVATION DATA TO ESTABLISH NEW TRENDS IN THE FORECAST GRIDS. THE FORECAST WAS ON TRACK OVERALL...ALTHOUGH THE FOG THAT WAS FORECAST TO FORM OVERNIGHT WAS NOT NEARLY AS EXTENSIVE AS ORIGINAL THINKING INDICATED. WITH THE FORECAST IN PRETTY GOOD SHAPE OVERALL...NO UPDATE IS PLANNED AT THIS TIME. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 313 AM EDT SAT JUL 20 2013 MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL LARGE SCALE WEATHER PATTERN AND SENSIBLE WEATHER FOR THE NEXT COUPLE OF DAYS. A WARM AND HUMID AIR MASS WILL REMAIN IN PLACE ACROSS EASTERN KENTUCKY TODAY AND TOMORROW...AS SOUTHERLY FLOW PERSISTS AHEAD OF A SLOWLY APPROACHING COLD FRONT. THE WEATHER TODAY SHOULD START OUT QUIET...AS THE LACK OF A GOOD TRIGGER FOR CONVECTION SHOULD KEEP SHOWER AND STORM ACTIVITY TO A MINIMUM THROUGH EARLY THIS AFTERNOON. SHOWERS AND STORMS WILL GRADUALLY INCREASE IN COVERAGE BEGINNING MID AFTERNOON TODAY...AS THE COLD FRONT FINALLY BEGINS MAKING ITS SOUTHWARD PUSH. THE BEST CHANCE FOR RAIN WILL BEGIN EARLY THIS EVENING NORTH OF THE MOUNTAIN PARKWAY. THE FRONT IS THEN PROGGED TO SAG SOUTHWARD OUT OF THE OHIO VALLEY AND ACROSS CENTRAL AND EASTERN KENTUCKY OVERNIGHT TONIGHT. ONCE LOSS OF DAYTIME HEATING BEGINS TO OCCUR...ANY SHOWERS AND STORMS WILL DECREASE IN COVERAGE...WITH ONLY SCATTERED SHOWERS AND ISOLATED STORMS EXPECTED DURING THE NIGHT TIME HOURS. ONCE THE SUN HAS A BEEN UP FOR AWHILE ON SUNDAY...THE FRONT WILL BECOME ACTIVE ONCE AGAIN...WITH NUMEROUS SHOWERS AND STORMS EXPECTED ACROSS THE AREA FROM LATE SUNDAY MORNING THROUGH THE END OF THE DAY ON SUNDAY. DUE TO SLUGGISH MIDDLE AND UPPER LEVEL WINDS...ANY SHOWERS AND STORMS THAT FORM WILL BE VERY SLOW MOVING...WHICH COULD LEAD TO LOCALIZED HEAVY RAIN AND POSSIBLY MINOR FLOODING ISSUES. TEMPERATURES WILL BE QUITE HOT ONCE AGAIN TODAY...BUT WITH THE GROUND STILL BEING SOMEWHAT MOIST FROM RECENT RAINFALL...AND WITH AREA VEGETATION IN FULL LEAF...90 DEGREE READINGS WILL BE DIFFICULT TO COME BY. WITH THAT IN MIND...LOWERED TODAYS HIGH TEMPERATURES ACROSS THE BOARD TO REFLECT THIS. WILL LIKELY SEE READINGS TOP OUT MOSTLY IN THE UPPER 80S AREA WIDE...WITH ISOLATED OCCURRENCES OF 90 HERE AND THERE. HIGHS ON SUNDAY WILL LIKELY RUN SLIGHTLY BELOW NORMAL...DUE TO SHOWER AND STORM ACTIVITY AND THE PASSAGE OF THE COLD FRONT. HIGHS ON SUNDAY ARE EXPECTED TO TOP OUT IN THE LOWER 80S. OVERNIGHT LOWS WILL BOTTOM OUT AROUND A BALMY 70 DEGREES. WINDS WILL REMAIN FAIRLY LIGHT ACROSS THE AREA TODAY AND TOMORROW. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 313 AM EDT SAT JUL 20 2013 THE SYNOPTIC PATTERN OVER THE EASTERN U.S. NEXT WEEK WILL FEATURE THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EARLY IN THE WEEK WITH A LEAD SHORTWAVE TRAVERSING THE OHIO VALLEY MONDAY AND MONDAY NIGHT. OUR FORECAST WILL FEATURE THE HIGHEST RAIN CHANCES WITH THIS LEAD SHORTWAVE ACTING AS THE FOCUS FOR SHOWERS AND THUNDERSTORMS MONDAY AND MONDAY NIGHT. THIS FEATURE WILL PASS BY BUT THE UPPER LEVEL TROUGH IS PROGGED TO HANG OUT WITH IT/S AXIS ALIGNED DOWN THE APPALACHIAN CHAIN THROUGH AT LEAST FRIDAY...WITH SIGNS IN THE MODELING THAT IT WILL GET REINFORCED NEXT WEEKEND. THIS SPELLS A CONTINUATION OF UNSETTLED WEATHER WITH DAILY SHOWER AND THUNDERSTORM CHANCES. A COLD FRONT WILL SLOWLY DROP THROUGH THE OHIO VALLEY MIDWEEK RESULTING IN SCATTERED SHOWERS/STORMS...ESPECIALLY DURING THE AFTERNOON AND EARLY EVENING HOURS. THE FRONT IS PROGGED TO DROP TO OUR SOUTH FINALLY BY LATE THURSDAY INTO FRIDAY WITH A WEAK AREA OF HIGH PRESSURE SLIDING DOWN INTO THE REGION. TRENDED RAIN CHANCES DOWNWARD FROM INHERITED NUMBERS THURSDAY AND FRIDAY...BUT DID NOT REMOVE THEM TOTALLY JUST YET. THE GOOD NEWS IS THAT TEMPERATURES AND DEWPOINTS WILL BE ON A DOWNWARD TREND DURING THE PERIOD. TEMPS WILL SETTLE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR...WITH HIGHS GENERALLY IN THE LOW TO MID 80S EACH DAY. DEWPOINTS WILL REMAIN HIGH...AROUND 70...UNTIL THE COLD FRONT DROPS TO OUR SOUTH LATE IN THE WEEK. THIS SHOULD DROP DEWS BACK INTO THE 60S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 123 PM EDT SAT JUL 20 2013 A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL CONTINUE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...AR LONG TERM...ABE AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
923 AM EDT SAT JUL 20 2013 .UPDATE... ISSUED AT 923 AM EDT SAT JUL 20 2013 BAND OF ENHANCED CU IS PUSHING SOUTHEAST...EXTENDING FROM NEAR DANVILLE TO WEST LIBERTY THIS MORNING. BASED ON INITIAL ANALYSIS THIS MORNING...THIS MAY HELP TO GENERATE SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS HEADING INTO THE AFTERNOON HOURS. HOWEVER...THIS ACTIVITY WILL LIKELY SHIFT SOUTHEAST AS WE HEAD INTO THE LATE AFTERNOON HOURS AS SUBSIDENCE AHEAD OF THE APPROACHING COLD FRONT FROM THE NORTH OVERSPREADS THE AREA. LATEST HRRR TAKES MOST OF THE DAY TO GET ANY PRECIPITATION AS FAR SOUTH AS FLEMING COUNTY (LIKELY NOT UNTIL AFTER 22 OR 23Z). THUS...GOING TO BACK OFF ON THE HIGHER PRECIPITATION CHANCES TODAY...BUT STILL CARRY SOME ISOLATED COVERAGE ACROSS THE SOUTHEAST ASSOCIATED WITH THE BAND OF ENHANCED CU AS IT DROPS SOUTHEAST. OTHERWISE...WILL GO WITH HIGHER POPS NORTH OF I-64 AFTER 22Z. SOME QUESTION AS TO HOW MUCH ACTIVITY LINGERS INTO TONIGHT AS THE FRONT WASHES OUT OVER THE AREA. WILL DROP POPS BACK FOR THE OVERNIGHT HOURS AS COVERAGE WILL LIKELY REMAIN MORE ISOLATED TO SCATTERED ALONG THE BOUNDARY SINCE IT WILL BE HARD TO SEE MUCH ORGANIZED ACTIVITY ALONG THE STALLED BOUNDARY. UPDATE WILL BE OUR SHORTLY. UPDATE ISSUED AT 705 AM EDT SAT JUL 20 2013 INGESTED THE MOST CURRENT OBSERVATION DATA TO ESTABLISH NEW TRENDS IN THE FORECAST GRIDS. THE FORECAST WAS ON TRACK OVERALL...ALTHOUGH THE FOG THAT WAS FORECAST TO FORM OVERNIGHT WAS NOT NEARLY AS EXTENSIVE AS ORIGINAL THINKING INDICATED. WITH THE FORECAST IN PRETTY GOOD SHAPE OVERALL...NO UPDATE IS PLANNED AT THIS TIME. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 313 AM EDT SAT JUL 20 2013 MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL LARGE SCALE WEATHER PATTERN AND SENSIBLE WEATHER FOR THE NEXT COUPLE OF DAYS. A WARM AND HUMID AIR MASS WILL REMAIN IN PLACE ACROSS EASTERN KENTUCKY TODAY AND TOMORROW...AS SOUTHERLY FLOW PERSISTS AHEAD OF A SLOWLY APPROACHING COLD FRONT. THE WEATHER TODAY SHOULD START OUT QUIET...AS THE LACK OF A GOOD TRIGGER FOR CONVECTION SHOULD KEEP SHOWER AND STORM ACTIVITY TO A MINIMUM THROUGH EARLY THIS AFTERNOON. SHOWERS AND STORMS WILL GRADUALLY INCREASE IN COVERAGE BEGINNING MID AFTERNOON TODAY...AS THE COLD FRONT FINALLY BEGINS MAKING ITS SOUTHWARD PUSH. THE BEST CHANCE FOR RAIN WILL BEGIN EARLY THIS EVENING NORTH OF THE MOUNTAIN PARKWAY. THE FRONT IS THEN PROGGED TO SAG SOUTHWARD OUT OF THE OHIO VALLEY AND ACROSS CENTRAL AND EASTERN KENTUCKY OVERNIGHT TONIGHT. ONCE LOSS OF DAYTIME HEATING BEGINS TO OCCUR...ANY SHOWERS AND STORMS WILL DECREASE IN COVERAGE...WITH ONLY SCATTERED SHOWERS AND ISOLATED STORMS EXPECTED DURING THE NIGHT TIME HOURS. ONCE THE SUN HAS A BEEN UP FOR AWHILE ON SUNDAY...THE FRONT WILL BECOME ACTIVE ONCE AGAIN...WITH NUMEROUS SHOWERS AND STORMS EXPECTED ACROSS THE AREA FROM LATE SUNDAY MORNING THROUGH THE END OF THE DAY ON SUNDAY. DUE TO SLUGGISH MIDDLE AND UPPER LEVEL WINDS...ANY SHOWERS AND STORMS THAT FORM WILL BE VERY SLOW MOVING...WHICH COULD LEAD TO LOCALIZED HEAVY RAIN AND POSSIBLY MINOR FLOODING ISSUES. TEMPERATURES WILL BE QUITE HOT ONCE AGAIN TODAY...BUT WITH THE GROUND STILL BEING SOMEWHAT MOIST FROM RECENT RAINFALL...AND WITH AREA VEGETATION IN FULL LEAF...90 DEGREE READINGS WILL BE DIFFICULT TO COME BY. WITH THAT IN MIND...LOWERED TODAYS HIGH TEMPERATURES ACROSS THE BOARD TO REFLECT THIS. WILL LIKELY SEE READINGS TOP OUT MOSTLY IN THE UPPER 80S AREA WIDE...WITH ISOLATED OCCURRENCES OF 90 HERE AND THERE. HIGHS ON SUNDAY WILL LIKELY RUN SLIGHTLY BELOW NORMAL...DUE TO SHOWER AND STORM ACTIVITY AND THE PASSAGE OF THE COLD FRONT. HIGHS ON SUNDAY ARE EXPECTED TO TOP OUT IN THE LOWER 80S. OVERNIGHT LOWS WILL BOTTOM OUT AROUND A BALMY 70 DEGREES. WINDS WILL REMAIN FAIRLY LIGHT ACROSS THE AREA TODAY AND TOMORROW. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 313 AM EDT SAT JUL 20 2013 THE SYNOPTIC PATTERN OVER THE EASTERN U.S. NEXT WEEK WILL FEATURE THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EARLY IN THE WEEK WITH A LEAD SHORTWAVE TRAVERSING THE OHIO VALLEY MONDAY AND MONDAY NIGHT. OUR FORECAST WILL FEATURE THE HIGHEST RAIN CHANCES WITH THIS LEAD SHORTWAVE ACTING AS THE FOCUS FOR SHOWERS AND THUNDERSTORMS MONDAY AND MONDAY NIGHT. THIS FEATURE WILL PASS BY BUT THE UPPER LEVEL TROUGH IS PROGGED TO HANG OUT WITH IT/S AXIS ALIGNED DOWN THE APPALACHIAN CHAIN THROUGH AT LEAST FRIDAY...WITH SIGNS IN THE MODELING THAT IT WILL GET REINFORCED NEXT WEEKEND. THIS SPELLS A CONTINUATION OF UNSETTLED WEATHER WITH DAILY SHOWER AND THUNDERSTORM CHANCES. A COLD FRONT WILL SLOWLY DROP THROUGH THE OHIO VALLEY MIDWEEK RESULTING IN SCATTERED SHOWERS/STORMS...ESPECIALLY DURING THE AFTERNOON AND EARLY EVENING HOURS. THE FRONT IS PROGGED TO DROP TO OUR SOUTH FINALLY BY LATE THURSDAY INTO FRIDAY WITH A WEAK AREA OF HIGH PRESSURE SLIDING DOWN INTO THE REGION. TRENDED RAIN CHANCES DOWNWARD FROM INHERITED NUMBERS THURSDAY AND FRIDAY...BUT DID NOT REMOVE THEM TOTALLY JUST YET. THE GOOD NEWS IS THAT TEMPERATURES AND DEWPOINTS WILL BE ON A DOWNWARD TREND DURING THE PERIOD. TEMPS WILL SETTLE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR...WITH HIGHS GENERALLY IN THE LOW TO MID 80S EACH DAY. DEWPOINTS WILL REMAIN HIGH...AROUND 70...UNTIL THE COLD FRONT DROPS TO OUR SOUTH LATE IN THE WEEK. THIS SHOULD DROP DEWS BACK INTO THE 60S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 705 AM EDT SAT JUL 20 2013 FOG WAS NOT NEARLY AS WIDESPREAD AS THE EARLIER TAF INDICATED IT WOULD BE...ESPECIALLY AT JKL AND SME. LOZ EXPERIENCE A FEW HOURS OF FOG DURING THE PREDAWN HOURS THIS MORNING...WITH LIFR CONDITIONS FOR A BRIEF PERIOD. AS FOR THE REST OF TODAY...SCATTERED SHOWERS AND STORMS ARE EXPECTED TO BEGIN AFFECTING JKL AROUND 2Z TONIGHT...AND LOZ AND SME AROUND 4Z...AS A COLD FRONT BEGINS TO MOVE SLOWLY SOUTHWARD OUT OF THE OHIO VALLEY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...AR LONG TERM...ABE AVIATION...AR
AREA FORECAST DISCUSSION
NWS CARIBOU ME
310 PM EDT SAT JUL 20 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT. A DRIER AND COOLER CANADIAN AIRMASS WILL THEN BUILD INTO THE AREA ON SUNDAY AND HOLD OVER THE REGION THROUGH MONDAY. THE NEXT LOW PRESSURE FROM THE GREAT LAKES WILL APPROACH THE REGION LATE MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /THROUGH SUNDAY/... A COLD FRONT WILL MOVE THROUGH THE REGION OVERNIGHT FOLLOWED BY CANADIAN HIGH PRES FOR SUNDAY. THIS HIGH WILL REMAIN IN CONTROL THROUGH EARLY NEXT WEEK. SOME CONVECTION HAS FIRED UP MAINLY ACROSS NORTHERN AND WESTERN AREAS(SUB-SEVERE) AS SOME UPPER LEVEL DIVERGENCE SEEN ON THE SATL WV IMAGERY AND 12Z UA. THE BEST SHOT FOR ANY STRONGER STORMS WILL BE ACROSS THE DOWNEAST AND COAST INTO THE EVENING AND THEN ACTIVITY WILL WEAKEN. THE BEST FORCING AND INSTABILITY WILL SHIFT TO THE EAST. ADDED SOME FOG TO THE GRIDS FOR TONIGHT INTO EARLY SUNDAY MORNING BASED ON ANTICIPATED CLEARING AND COOLER TEMPERATURES W/A WET GROUND. ADJUSTED THE OVERNIGHT LOW USING A BLEND OF THE NAM12 AND ECMWF. POPS ARE A BLEND OF THE RUC AND DOWNSCALED NAM WHICH SHOW PRECIP CHANCES WINDING DOWN AFTER 00Z. SUNDAY LOOKS TO BE SUNNY AND PLEASANT W/HIGH PRES BUILDING IN FROM CANADA. THINKING ATTM IS TO TAKE W/CONSISTENCY AND KEEP THE MIDNIGHT CREW`S MAXES OF LOWER 70S NORTHERN CWA AND MID TO UPPER 70S CENTRAL AND DOWNEAST. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... HIGH PRESSURE WILL SETTLE OVER THE AREA SUNDAY NIGHT. WITH LIGHT WINDS...CLEAR SKIES AND RELATIVELY DRY AIR THE NIGHT WILL BE COOL WITH LOWS DROPPING INTO THE 40S NORTH TO NEAR 50 DOWNEAST. THIS WILL BE FOLLOWED BY A MOSTLY SUNNY AND SEASONABLE DAY ON MONDAY. CLOUDS WILL BEGIN TO INCREASE FROM THE SOUTHWEST LATE IN THE DAY AS MOISTURE LIFTS NORTH FROM LOW PRESSURE TRACKING INTO SOUTHERN NEW ENGLAND. CLOUDS WILL CONTINUE TO INCREASE MONDAY NIGHT AND SOME RAIN MAY SPREAD INTO THE AREA LATE. THE BEST CHANCE FOR RAIN WILL BE ALONG THE FRONTAL BOUNDARY WHICH WILL BE NEAR THE COAST. THE LOW WILL TRACK JUST OFFSHORE ON TUESDAY BRINGING A CHANCE OF RAIN TO THE AREA. THE BEST CHANCE FOR RAIN WILL BE ALONG COASTAL AREAS. A COLD FRONT WILL APPROACH THE WEST LATE IN THE DAY. WARM AND HUMID AIR MOVING NORTH AHEAD OF THE FRONT BENEATH RELATIVELY COOLER AIR ALOFT MAY PRODUCE SOME THUNDERSTORMS IN WESTERN AREAS LATE IN THE DAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... A WEAK LOW WILL BE TRACKING OFF THE COAST TUESDAY NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. THE LOW MAY BRING SOME RAIN TO COASTAL AREAS EARLY TUESDAY NIGHT WHILE THE APPROACHING FRONT BRINGS SOME SHOWERS AND POSSIBLY THUNDERSTORMS TO FAR WESTERN AREAS. THE FRONT IS EXPECTED TO CROSS THE AREA EARLY WEDNESDAY BRINGING SOME SHOWERS AND ISOLATED THUNDERSTORMS MAINLY TO THE DOWNEAST REGION. HIGH PRESSURE SHOULD THEN BRING DRIER AIR WITH CLEARING LATER WEDNESDAY INTO THURSDAY. ANOTHER FRONT MAY APPROACH LATER FRIDAY INTO SATURDAY WITH INCREASED HUMIDITY FRIDAY INTO SATURDAY. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: UNSETTLED CONDITIONS THROUGH AT THE START OF THE PERIOD. MVFR NORTH...BECMG VFR EARLY EVENING. A BRIEF PERIOD OF MVFR AND PERHAPS IFR FOR KBHB/KBGR THROUGH TONIGHT IN SHRA/TSRA AND SOME FOG. VFR ALL SITES ON SUNDAY. SHORT TERM: VFR CONDITIONS ARE EXPECTED SUNDAY NIGHT INTO MONDAY WITH HIGH PRESSURE AND MOSTLY CLEAR SKIES. CONDITIONS WILL LIKELY BEGIN VFR MONDAY NIGHT BUT MAY LOWER TO MVFR OR IFR LATE AS LOW CLOUDS AND SHOWERS MOVE IN. MVFR CONDITIONS ARE EXPECTED TUESDAY NIGHT INTO EARLY WEDNESDAY. HIGH PRESSURE MAY THEN BRING AN IMPROVEMENT TO VFR WEDNESDAY INTO EARLY FRIDAY. LOWERING CLOUDS AND SHOWERS MAY LOWER CONDITIONS TO MVFR FRIDAY NIGHT INTO SATURDAY AS THE NEXT FRONT MOVES IN. && .MARINE... NEAR TERM: SEAS 3-5 FT ATTM. WAVE GUIDANCE INCLUDING THE SWAN RUNNING TOO HIGH AS THE LATEST OBS SHOWED NO MORE THAN 4 FT(44027). WINDS ARE EXPECTED TO BECOME GUSTY W/THE COLD FRONT TONIGHT W/SPEEDS OF 25 KT BRIEFLY. THE WINDS WILL SUBSIDE ON SUNDAY DOWN TO 10 KT AS HIGH PRES PUSHES E. SHORT TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA THIS WEEKEND INTO EARLY NEXT WEEK. HIGH PRESSURE SHOULD BRING CLEAR AND PLEASANT CONDITIONS SUNDAY INTO MONDAY. LOWER CLOUDS...FOG AND SOME RAIN MAY MOVE OVER THE WATERS ON TUESDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...NORTON/HEWITT SHORT TERM...BLOOMER LONG TERM...BLOOMER AVIATION...NORTON/HEWITT/BLOOMER MARINE...NORTON/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
630 AM EDT SAT JUL 20 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE REGION LATE TODAY AND THIS EVENING. A DRIER AND COOLER CANADIAN AIRMASS WILL THEN BUILD INTO THE AREA ON SUNDAY AND HOLD OVER THE REGION THROUGH MONDAY. THE NEXT LOW PRESSURE FROM THE GREAT LAKES WILL APPROACH THE REGION LATE MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... 630 AM UPDATE...SATELLITE IMAGERY IS SHOWING MID CLOUDS ACROSS MAINLY WESTERN PORTIONS OF THE FORECAST AREA THIS MORNING, WITH SUNSHINE IN EASTERN MAINE. THESE CLOUDS WILL CONTINUE TO PUSH EASTWARD THROUGH THIS MORNING. THERE`S NOT MUCH ON RADAR ATTM, JUST SOME ISOLATED SHOWERS OVER THE SAINT JOHN VALLEY AND SOUTHERN QUEBEC. ADDITIONAL SHOWERS WILL CONTINUE TO DEVELOP, THOUGH THE BULK OF THE ACTIVITY SHOULD HOLD OFF UNTIL AT LEAST MID MORNING, ESPECIALLY OVER NORTHERN MAINE. BOTH THE LATEST RUN AND HRRR MODEL RUNS CONCUR WITH THIS THINKING. HAVE THEREFORE UPDATED THE FORECAST TO REDUCE SKY COVER AND POPS OVER THE NEXT FEW HOURS. OTHERWISE, THE PREVIOUS FORECAST LOOKS ON TRACK. STRONG TO SEVERE STORMS ONCE AGAIN POSSIBLE TODAY, ESPECIALLY ACROSS CENTRAL AND INTERIOR DOWNEAST MAINE. SPC HAS THESE AREAS IN A SLIGHT RISK FOR SEVERE WEATHER THIS AFTERNOON AND EVENING. A STRONG COLD FRONT CURRENTLY LIES ACROSS CENTRAL QUEBEC EARLY THIS MORNING, STRETCHING SOUTHWESTWARD THROUGH THE GREAT LAKES. THIS FEATURE WILL SLOWLY MOVE SOUTHWARD TODAY, CROSSING THE FORECAST AREA THIS AFTERNOON AND EVENING. MOISTURE CONVERGENCE ALONG THIS FRONT WILL SERVE AS A FOCUS FOR SHOWERS AND THUNDERSTORMS, ESPECIALLY THIS AFTERNOON. THE BEST MOISTURE AND INSTABILITY WILL LIE SOUTH OF A HOULTON-MILLINOCKET-GREENVILLE LINE; DEWPOINTS AROUND 70 AND SBCAPES OF 1000+ J/KG WILL EXIST IN THIS REGION THIS AFTERNOON. THIS INSTABILITY COMBINED WITH 0-6KM SHEAR AROUND 40 KT WILL ALLOW THUNDERSTORMS TO BECOME STRONG TO SEVERE OVER CENTRAL AND INTERIOR DOWNEAST AREAS, WITH DAMAGING WINDS THE MAIN THREAT. PWATS NEARING 2 INCHES AND FREEZING LEVELS AOA 14 KFT INDICATE THAT HEAVY RAIN WILL BE POSSIBLE AS WELL. ACROSS THE CROWN OF MAINE, SHOWERS AND THUNDERSTORMS WILL BE MORE SCATTERED IN NATURE, WITH SOME LOCATIONS EVEN SEEING SOME SUNSHINE FROM TIME TO TIME. THE EARLIER TIMING OF THE FRONTAL PASSAGE AND SLIGHTLY LOWER MOISTURE CONTENT WILL LIMIT ANY SEVERE POTENTIAL. THAT BEING SAID, GUSTY WINDS AND BRIEFLY HEAVY DOWNPOURS ARE STILL A POSSIBILITY WITH ANY STRONGER STORMS. RELIEF FROM THE PAST FEW DAYS` MUGGINESS FINALLY ARRIVES TONIGHT AS COOL, DRY CANADIAN HIGH PRESSURE SETTLES OVER THE REGION BEHIND THE FRONT. SHOWERS AND THUNDERSTORMS WILL QUICKLY COME TO AN END AS DEWPOINTS DROP AND SKIES CLEAR OUT. LOWS WILL BE MUCH MORE COMFORTABLE, ESPECIALLY IN NORTHERN MAINE WHERE TEMPERATURES WILL DROP TO AROUND 50. CENTRAL AND DOWNEAST MAINE WILL STAY BIT WARMER, GENERALLY IN THE UPPER 50S TO AROUND 60. && .SHORT TERM /SUNDAY THROUGH MONDAY/... SUN STILL LOOKS TO BE SIG COOLER AND MUCH DRIER AS CANADIAN AIR ACCOMPANIED BY SFC DWPTS IN THE 40S MOVES INTO THE FA. THE SFC HI THEN CRESTS OVR THE FA SUN NGT PROVIDING GOOD RADIATIONAL COOLING WITH OVRNGT LOWS DROPPING TO ARND 40 DEG F FOR THE COOLEST NRN VLYS WITH 40S ELSEWHERE AND ARND 50 ALG THE IMMEDIATE DOWNEAST COAST. MON SHOULD CONT FAIR WITH MSLY SUNNY SKIES...WITH LGT SW RETURN FLOW WINDS ARND SFC HI PRES DEPARTING E THRU THE MARITIMES ALLOWING A RECOVERY OF HI TEMPS AT LEAST 5 DEG WARMER THAN SUN AFTN...XCPT DOWNEAST AREAS WHICH WILL BE HELD BACK A FEW DEG DUE TO AN AFTN SEA BREEZE. MON NGT WILL BEGIN FAIR...THEN INCREASING HI CLDNSS WILL MOVE SW TO NE ACROSS THE FA LATE MON NGT AHEAD OF SFC LOW PRES SYSTEMS AND AN ASSOCIATED S/WVS ADVCG ENE FROM THE GREAT LKS AND CNTRL CAN. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... FCSTS OF THE NAO TELECONNECTION PATTERN TRENDING TOWARD NEAR ZERO AND THE PNA PATTERN TRENDING POSITIVE SHOULD KEEP 500 MB HTS LOWER THRU THE LONG RANGE AS THE MEAN LW TROF HOLDS OVR E CNTRL CAN AND THE ERN GREAT LKS. SUBSEQUENTLY HI TEMPS THIS PD WILL MSLY BE AT TO BLO NORMAL. THE COOLEST DAY POTENTIALLY...WILL BE TUE DUE TO LOWERING CLD CVR AND SHWRS MOVG INTO THE FA FROM THE WSW AS A SFC LOW FROM THE GREAT LAKES MOVES TOWARD NW ME TUE NGT. FOR NOW... WE SPLIT THE DIFFERENCE BETWEEN BLENDED MODEL AND MOS HI TEMPS WITH MODELS INDICATING MUCH COOLER HI TEMPS TUE AFTN DUE TO RN` COOLED AIR...JUST IN CASE FASTER MODELS SUCH AS THE GFS ARE TO FAST IN BRINGING THICKER CLD CVR AND SHWRS INTO THE FA TUE. USING THE CONSENSUS APCH...WE SHOW THE GREATEST POPS WITH THE GREAT LKS/E CNTRL CAN S/WV SYSTEMS TO BE TUE NGT WHERE WE SHOW UP TO LOW LIKELY POPS OVR PTNS OF DOWNEAST AND E CNTRL PTNS OF THE FA. WITH SRLY WINDS WHICH DIMINISH WITHE THE APCH OF THE SFC TROF AXIS BY ERLY WED MORN...WE MENTION PATCHY LATE NGT FOG WITH SHWRS FOR LATE TUE NGT. WITH LITTLE OR NO SBCAPE SHOWN FOR OUR FA WITH THIS SYSTEM TUE AFTN AND TUE NGT...WE DO NOT INDICATE ANY THUNDER WITH SHWRS ATTM...BUT THIS CAN BE RE-EVALUATED IN FUTURE FCST UPDATES IN CASE ELEVATED CNVCTN PLAYS A ROLE. OTHERWISE...A SLOW MOVG COLD FRONT WILL CROSS THE FA FROM QB PROV LATER WED INTO WED EVE AS THE UPPER TROF CROSSES THE REGION BRINGING THE CHC OF ADDITIONAL SHWRS. CANNOT RULE OUT THUNDER... BUT GIVEN THE RANGE OF TMG OF THE COLD FRONT CROSSING FOR WED... WE WILL WILL HOLD OFF IN CALLING FOR THUNDER IN THE FCST GRIDS ATTM FOR THIS PD. OTHERWISE...PRTL CLRG IS XPCTD WED NGT THRU FRI...ALTHOUGH THE CONSENSUS OF MODEL SOLUTIONS STALL THE COLD FRONT JUST E OF THE FA DURG THIS TM...RESULTING IN US KEEPING CHC SHWRS POPS AND CLDNSS BANKED UP ALG THE SE PERIPHERY OF THE FA DURG THESE PDS. FOR NOW...WE SHOW NEAR NORMAL HI AND LOW TEMPS ACROSS THE FA TUE NGT THRU FRI...SUBJECT TO CHG OF COURSE DEPENDING ON FUTURE MODEL TRENDS ON THE WX SYSTEMS XPCTD TO AFFECT THE FA DURING THE LONG RANGE. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: OUTSIDE OF SOME LINGERING MVFR VISIBILITIES IN FOG AT KBGR AND KBHB, VFR CONDITIONS WILL PREVAIL THIS MORNING BEFORE GIVING WAY TO MVFR AS ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS AFFECTS THE REGION. THE SOUTHERN TERMINALS WILL SEE THE STRONGEST ACTIVITY, WITH HEAVY RAINFALL AND GUSTY WINDS POSSIBLE. IFR CONDITIONS ARE POSSIBLE IN ANY THUNDERSTORMS. A COLD FRONT WILL QUICKLY CROSS THE REGION TONIGHT, FOLLOWED BY MUCH DRIER AIR. AS SUCH, PRECIPITATION WILL END AND SKIES CLEAR. CONDITIONS WILL RETURN TO VFR AT ALL TERMINALS BY 06Z. SHORT TO LONG TERM: VFR ALL SITES THRU MON NGT...THEN LOWERING TO MVFR IN LOW CLDNSS AND SHWRS FROM SW TO NE BY TUE AFTN AND TO IFR WITH SHWRS AND PATCHY FOG TUE NGT. CONDITIONS THEN SLOWLY IMPROVE TO MVFR BY WED AFTN WITH LESSENING CVRG OF SHWRS. && .MARINE... NEAR TERM: SOUTHWEST WINDS 15-20 KT AND SOUTH SWELL OF 4 TO 6 FEET WILL CONTINUE THROUGH TODAY AHEAD OF A COLD FRONT MOVING SOUTH OUT OF QUEBEC. THIS FRONT WILL CROSS THE WATERS THIS EVENING, TURNING WINDS TO THE NW AND ALLOWING SEAS TO SUBSIDE. THEREFORE, THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS REMAINS IN PLACE THROUGH THIS EVENING. SHORT TO LONG TERM: NO HDLNS NEEDED UNTIL TUE NGT INTO WED...WHEN AN SCA FOR HAZ SEAS MAY BE NEEDED FOR OUR OUTER MZS DUE TO A SRLY WIND FETCH AHEAD OF LOW PRES MOVG NE THRU ERN QB. WENT BLO A BLEND OF WW3 AND SWAN NAM BY USING THE SMOOTHING FUNCTION ADJACENT TO LAND...WHICH LOWERED WV HTS MOST OVR THE INNER BAY/HARBOR MZ. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM EDT THIS EVENING FOR ANZ050-051. && $$ NEAR TERM...HASTINGS SHORT TERM...VJN LONG TERM...VJN AVIATION...HASTINGS/VJN MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1011 PM EDT SUN JUL 21 2013 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST DURING THE EARLY PORTION OF THIS WEEK...AS A COLD FRONT BECOMES NEARLY STATIONARY FROM THE OHIO VALLEY TO THE NORTHERN MID ATLANTIC STATES. MEANWHILE...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL PERSIST ACROSS THE REGION. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... LATEST WX ANALYSIS SHOWS WEAKENING SFC FRONT FROM JUST SOUTH OF LONG ISLAND NY...EXTENDING W-SW BACK INTO THE OHIO AND MIDDLE MISSOURI VALLEYS. BULK OF CONVECTION WHICH ERUPTED ALONG SFC TROUGH...AND DUMPED BETWEEN 3 AND 5 INCHES OVER PARTS OF THE PIEDMONT AND MIDDLE PENINSULA EARLIER THIS EVENING...HAVE GREATLY DIMINISHED IN INTENSITY AND AREAL CVG WITH LOSS OF HEATING AND AS NOCTURNAL STABILITY SETS IN. HRRR HAS HANDLED TRENDS RATHER WELL THIS EVENING AND HV CONTINUED TO LEAN IN ITS DIRECTION OVERNIGHT. OVERALL, WHILE INSTABILITY AND SYNOPTIC SCALE FORCING WANE SIGNIFICANTLY OVERNIGHT, WEAK LLVL CONVERGENCE ALONG THE TROUGH AXIS PERSISTS. THUS, WILL RETAIN A SLIGHT CHC/LOW CHC POP FOR AN ISO TO WIDELY SCT SHRA AFTER MIDNIGHT. ANOTHER WARM AND HUMID OVERNIGHT IS EXPECTED WITH LOWS IN THE LOW/MID 70S...UNDER A PARTLY TO MOSTLY CLOUDY SKY. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... THE OVERALL PATTERN REMAINS UNSETTLED MONDAY AS A SURFACE BOUNDARY/WEAK LOW STALL OVER THE AREA. ADDITIONALLY...A VIGOROUS TROUGH CARVES OVER THE GREAT LAKES. A LEADING SHORTWAVE EJECTS OUT OF THE TROUGH ACROSS THE OHIO VALLEY TOWARD THE APPALACHIANS MONDAY AFTERNOON/EVENING. HENCE...HIGH CHANCE/LOW-END LIKELY POPS ARE FORECAST MONDAY AFTN/EVENING. AFTERNOON HIGHS WILL TREND DOWN SLIGHTLY DUE TO INCREASED CLOUD COVER AND A HIGHER PROBABILITY OF SHOWERS/TSTMS (AND SHIFTING WIND DIRECTION MAINLY N)...ALTHOUGH DEWPOINTS WILL REMAIN IN THE LOW/MID 70S. HIGHS SHOULD RANGE FROM THE MID/UPPER 80S TO AROUND 90 MONDAY. ANY SEVERE THREAT LOOKS RATHER LIMITED MONDAY...WITH THE MAIN CONCERN AGAIN BEING HEAVY RAIN FROM SLOW MOVING STORMS. THE PARENT TROUGH PIVOTS N OF THE GREAT LAKES TUESDAY AS A SECONDARY WAVE LIFTS ACROSS THE MID ATLANTIC. THE LATEST DATA BRINGS THE WAVE THROUGH EARLIER IN THE DAY...FOLLOWED BY WESTERLY MID-LEVEL FLOW BY LATER AFTERNOON. GIVEN THIS...POPS HAVE BEEN LOWERED...ESPECIALLY W. HOWEVER..A WELL-DEFINED LEE SIDE TROUGH REMAINS OVER THE AREA...SO WILL MAINTAIN 30 POPS W...TO 40 E. HIGHS SHOULD AVERAGE IN THE UPPER 80S TO LOW 90S. THE 21/12Z GFS/NAM BRING YET ANOTHER SHORTWAVE TROUGH THROUGH THE REGION WEDNESDAY. THE MAIN MOISTURE FEED MAY BE WELL OFF THE COAST BY THIS TIME...SO WILL GO NO HIGHER THAN CHANCE POPS AT THIS TIME. HIGHS SHOULD AGAIN RANGE FROM THE UPPER 80S TO LOW 90S. LOWS THROUGH THE PERIOD SHOULD RANGE FROM 70-75. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... UPR TROF OVR THE ERN THIRD OF THE U.S. WED NGT THRU THU...WILL SHIFT EWRD AND OFFSHR THU NGT THRU FRI. THIS WILL PUSH FRNTL BNDRY ALNG OR JUST OFFSHR AT THE BEGINNING OF THE PERIOD...FARTHER OUT TO SEA. WEAK HI PRES WILL BLD INTO AND OVR THE AREA FOR FRI NGT INTO SAT. THEN...ANOTHER SHRTWV TROF AND ASSOCIATED COLD FRONT WILL APPROACH AND MOVE INTO THE REGION LATE SAT NGT THRU SUN. AT THIS TIME...WILL NOT BE GOING ANY HIGHER THAN 20% OR 30% THRU THE PERIOD...DUE TO LOW CONFIDENCE OF COVERAGE. MIN TEMPS WILL BE IN THE UPR 60S TO MID 70S THU MORNG...AND MAINLY IN THE MID 60S TO LWR 70S FRI...SAT AND SUN MORNGS. MAX TEMPS WILL GENERALLY BE IN THE MID TO UPR 80S THRU THE PERIOD. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... SHOWERS AND TSTMS CONT TO AFFECT THE CWA AS OF 0030Z WITH MOST OF THE ACTIVITY FROM THE EASTERN SHORE TO SE VA. OUTSIDE OF PRECIPITATION...CONDS HAVE BEEN GENERALLY VFR...WITH MVFR/IFR IN SHOWERS AND TSTMS. A STNRY FRONT CONTS ALONG THE PA/MD LINE AND A SFC TROUGH IS PUSHING THRU CENTRAL VA. MOST OF THE PRECIP ACTIVITY SHOULD BE ENDED BY MIDNIGHT. WINDS WILL BE LIGHT AND VRBL OVERNIGHT AND MOST OF THE CLOUDS SHOULD CLEAR FOR A SHORT PERIOD OF TIME. AS WITH THE PREVIOUS FEW NIGHTS...EXPECT SOME MVFR STRATUS/STRATOCU CLOUDS TO DEVELOP DURING THE EARLY MORNING AS LOW LEVEL MOISTURE GETS TRAPPED UNDER WEAK INVERSION. THESE CLOUDS SHOULD DIMINISH BY MID TO LATE MORNING ALONG WITH ANY PTCHY FOG THAT DEVELOPS. OUTLOOK...SCATTERED MAINLY AFTN AND EARLY EVENING TSTMS CAN BE EXPECTED MON THROUGH FRI WITH THE HIGHEST CHANCES MON AND WED. AVIATION CONDS MAY LWR BRIEFLY IN HEAVIER PCPN. PATCHY IFR FOG NEAR SUNRISE CANNOT BE RULED BUT NO WIDESPREAD IFR IS INDICATED THROUGH MID WEEK. && .MARINE... SUB-SCA CONDS WILL PREVAIL OVER THE NEXT SEVERAL DAYS OVER AREA WATERS. SWELLS WILL IMPACT THE COASTAL WATERS DUE TO STRONGER WINDS ASSOCIATED WITH THE BERMUDA HIGH WELL OFF THE COAST. ADDED SOME HEIGHT TO THE SEAS DUE TO THE SWELL...ESPECIALLY MONDAY NIGHT AND EARLY TUESDAY...BUT KEPT THEM BELOW 5 FT FOR OUR COASTAL ZONES. EXPECT LOCALLY STRONGER WNDS IN SHOWERS AND TSTMS THRU THE PERIOD. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ/LKB NEAR TERM...MAM SHORT TERM...AJZ/LKB LONG TERM...TMG/JEF AVIATION...LSA MARINE...LSA
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
837 PM EDT SUN JUL 21 2013 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST DURING THE EARLY PORTION OF THIS WEEK...AS A COLD FRONT BECOMES NEARLY STATIONARY FROM THE OHIO VALLEY TO THE NORTHERN MID ATLANTIC STATES. MEANWHILE...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL PERSIST ACROSS THE REGION. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... CURRENT SATELLITE IMAGERY AND REGIONAL RADAR MOSAIC INDICATE AN ORGANIZED LINE OF THUNDERSTORMS EXTENDING FROM NORTHERN VA SW ALONG THE PIEDMONT AND MOVING EAST. THIS LINE OF STORMS IS BEGIN DRIVEN BY THE TAIL END OF A SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN MID ATLANTIC...INTERACTING WITH A SURFACE TROUGH OVER THE AREA...AND FEEDING OFF AN AXIS OF >2500 J/KG OF MLCAPE PER SPC HRRR BASED MESOANALYSIS. ADDITIONAL SEA/BAY BREEZE CONVECTION IS DEVELOPING ACROSS THE LOWER BAY AND MD ATLANTIC COAST. THE PRIMARY LINE SHOULD PROGRESS EAST ACROSS CENTRAL/S-CENTRAL VA THROUGH THE LATE AFTERNOON AND EARLY EVENING. INITIALLY...0-6KM BULK SHEAR VALUES ARE PROGGED TO BE ~25KT BEFORE DECAYING BY EARLY EVENING. THEREFORE...THE BEST CHANCE OF AN ISOLATED SEVERE STORM (MAINLY WIND GUST) WOULD BE ACROSS THE NORTHERN PORTION OF THE AREA THROUGH THE REMAINDER OF THE AFTERNOON. THE SOUTHERN END OF THE LINE SHOULD EVENTUALLY DISSIPATE THIS EVENING DUE TO THE LOSS OF SURFACE HEATING AND A LACK OF LARGE SCALE FORCING AS THE SHORTWAVE ENERGY PULLS TOWARD NEW ENGLAND. FARTHER NE IN THE LOCAL AREA...SCT POPS WILL BE MAINTAINED THROUGH THE EVENING/EARLY OVERNIGHT IN CLOSER PROXIMITY TO THE SHORTWAVE. WARM AND HUMID CONDITIONS WILL PERSIST OVERNIGHT WITH LOWS IN THE LOW/MID 70S. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... THE OVERALL PATTERN REMAINS UNSETTLED MONDAY AS A SURFACE BOUNDARY/WEAK LOW STALL OVER THE AREA. ADDITIONALLY...A VIGOROUS TROUGH CARVES OVER THE GREAT LAKES. A LEADING SHORTWAVE EJECTS OUT OF THE TROUGH ACROSS THE OHIO VALLEY TOWARD THE APPALACHIANS MONDAY AFTERNOON/EVENING. HENCE...HIGH CHANCE/LOW-END LIKELY POPS ARE FORECAST MONDAY AFTN/EVENING. AFTERNOON HIGHS WILL TREND DOWN SLIGHTLY DUE TO INCREASED CLOUD COVER AND A HIGHER PROBABILITY OF SHOWERS/TSTMS (AND SHIFTING WIND DIRECTION MAINLY N)...ALTHOUGH DEWPOINTS WILL REMAIN IN THE LOW/MID 70S. HIGHS SHOULD RANGE FROM THE MID/UPPER 80S TO AROUND 90 MONDAY. ANY SEVERE THREAT LOOKS RATHER LIMITED MONDAY...WITH THE MAIN CONCERN AGAIN BEING HEAVY RAIN FROM SLOW MOVING STORMS. THE PARENT TROUGH PIVOTS N OF THE GREAT LAKES TUESDAY AS A SECONDARY WAVE LIFTS ACROSS THE MID ATLANTIC. THE LATEST DATA BRINGS THE WAVE THROUGH EARLIER IN THE DAY...FOLLOWED BY WESTERLY MID-LEVEL FLOW BY LATER AFTERNOON. GIVEN THIS...POPS HAVE BEEN LOWERED...ESPECIALLY W. HOWEVER..A WELL-DEFINED LEE SIDE TROUGH REMAINS OVER THE AREA...SO WILL MAINTAIN 30 POPS W...TO 40 E. HIGHS SHOULD AVERAGE IN THE UPPER 80S TO LOW 90S. THE 21/12Z GFS/NAM BRING YET ANOTHER SHORTWAVE TROUGH THROUGH THE REGION WEDNESDAY. THE MAIN MOISTURE FEED MAY BE WELL OFF THE COAST BY THIS TIME...SO WILL GO NO HIGHER THAN CHANCE POPS AT THIS TIME. HIGHS SHOULD AGAIN RANGE FROM THE UPPER 80S TO LOW 90S. LOWS THROUGH THE PERIOD SHOULD RANGE FROM 70-75. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... UPR TROF OVR THE ERN THIRD OF THE U.S. WED NGT THRU THU...WILL SHIFT EWRD AND OFFSHR THU NGT THRU FRI. THIS WILL PUSH FRNTL BNDRY ALNG OR JUST OFFSHR AT THE BEGINNING OF THE PERIOD...FARTHER OUT TO SEA. WEAK HI PRES WILL BLD INTO AND OVR THE AREA FOR FRI NGT INTO SAT. THEN...ANOTHER SHRTWV TROF AND ASSOCIATED COLD FRONT WILL APPROACH AND MOVE INTO THE REGION LATE SAT NGT THRU SUN. AT THIS TIME...WILL NOT BE GOING ANY HIGHER THAN 20% OR 30% THRU THE PERIOD...DUE TO LOW CONFIDENCE OF COVERAGE. MIN TEMPS WILL BE IN THE UPR 60S TO MID 70S THU MORNG...AND MAINLY IN THE MID 60S TO LWR 70S FRI...SAT AND SUN MORNGS. MAX TEMPS WILL GENERALLY BE IN THE MID TO UPR 80S THRU THE PERIOD. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... SHOWERS AND TSTMS CONT TO AFFECT THE CWA AS OF 0030Z WITH MOST OF THE ACTIVITY FROM THE EASTERN SHORE TO SE VA. OUTSIDE OF PRECIPITATION...CONDS HAVE BEEN GENERALLY VFR...WITH MVFR/IFR IN SHOWERS AND TSTMS. A STNRY FRONT CONTS ALONG THE PA/MD LINE AND A SFC TROUGH IS PUSHING THRU CENTRAL VA. MOST OF THE PRECIP ACTIVITY SHOULD BE ENDED BY MIDNIGHT. WINDS WILL BE LIGHT AND VRBL OVERNIGHT AND MOST OF THE CLOUDS SHOULD CLEAR FOR A SHORT PERIOD OF TIME. AS WITH THE PREVIOUS FEW NIGHTS...EXPECT SOME MVFR STRATUS/STRATOCU CLOUDS TO DEVELOP DURING THE EARLY MORNING AS LOW LEVEL MOISTURE GETS TRAPPED UNDER WEAK INVERSION. THESE CLOUDS SHOULD DIMINISH BY MID TO LATE MORNING ALONG WITH ANY PTCHY FOG THAT DEVELOPS. OUTLOOK...SCATTERED MAINLY AFTN AND EARLY EVENING TSTMS CAN BE EXPECTED MON THROUGH FRI WITH THE HIGHEST CHANCES MON AND WED. AVIATION CONDS MAY LWR BRIEFLY IN HEAVIER PCPN. PATCHY IFR FOG NEAR SUNRISE CANNOT BE RULED BUT NO WIDESPREAD IFR IS INDICATED THROUGH MID WEEK. && .MARINE... SUB-SCA CONDS WILL PREVAIL OVER THE NEXT SEVERAL DAYS OVER AREA WATERS. SWELLS WILL IMPACT THE COASTAL WATERS DUE TO STRONGER WINDS ASSOCIATED WITH THE BERMUDA HIGH WELL OFF THE COAST. ADDED SOME HEIGHT TO THE SEAS DUE TO THE SWELL...ESPECIALLY MONDAY NIGHT AND EARLY TUESDAY...BUT KEPT THEM BELOW 5 FT FOR OUR COASTAL ZONES. EXPECT LOCALLY STRONGER WNDS IN SHOWERS AND TSTMS THRU THE PERIOD. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ/LKB NEAR TERM...AJZ SHORT TERM...AJZ/LKB LONG TERM...TMG/JEF AVIATION...LSA MARINE...LSA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 PM EDT SAT JUL 20 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 419 PM EDT SAT JUL 20 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NE CANADA AND A WEAK RIDGE INTO MANITOBA RESULTING IN CONFLUENT WNW FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...A RIDGE EXTENDED FROM SRN MANTIOBA INTO NW ONTARIO TO NW LAKE SUPERIOR. ABUNDANT DIRUNAL CU HAD DEVELOPED IN THE COOL AIR TO THE NORTH OF LAKE SUPERIOR WHERE 850 MB TEMPS WERE DOWN TO 2C-3C. FARTHER SOUTH...VIS LOOP SHOWED ONLY SCT CU OVER THE W HALF OF UPPER MI. TONIGHT...WITH CLEAR SKIES AND LIGHT WINDS TONIGHT...FAVORABLE RADIATIONAL COOLING CONDITIONS IN THE DRY AIRMASS OVER THE REGION (PWAT BELOW 0.50 INCH)WILL ALLOW TEMPS TO DROP TO NEAR THE LOW END OF GUIDANCE...NEAR 40 OVER THE COLDER INLAND LOCATIONS. SUN...AS THE SFC HIGH SHIFTS EAST OF THE AREA AND THE MID LEVEL FLOW BECOMES MORE ZONAL...SRLY FLOW AND WAA WILL INCREASE AHEAD OF APPROACHING SHORTWAVE AND FRONTAL SYSTEM OVER THE NRN PLAINS. TEMPS SHOULD CLIMB INTO THE LOWER TO MID 70S INLAND WITH LOWER READINGS IN THE MID TO UPPER 60S ALONG THE GREAT LAKES. MODELS SUGGEST THAT THE GREATEST INCREASE IN MOISTURE AND STRONGER 300-310K ISENTROPIC LIFT WILL REMAIN TO THE SOUTH AND WEST OF UPPER MI FROM SRN MN INTO CNTRL WI LATE SUN AFTERNOON. SO...THE FCST MAINTAINS ONLY SLIGHT CHANCE POPS INTO THE FAR WEST .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 419 PM EDT SAT JUL 20 2013 UPPER AIR PATTERN THROUGH NEXT WEEK DRIVEN BY TWO AREAS OF LOWER HEIGHTS...ONE OVER GULF OF ALASKA/BRITISH COLUMBIA AND THE OTHER VCNTY OF HUDSON BAY ACROSS QUEBEC. IN BTWN THESE TWO...WNW FLOW HOLDS IN PLACE FROM WESTERN CANADA ACROSS GREAT LAKES. MOST PERSISTENT RIDGING WILL BE LIMITED TO SOUTHWEST PART OF CONUS. PATTERN DOES NOT LOOK APPRECIABLY WARM...ESPECIALLY COMPARED TO THE RECENT HEAT WAVE THAT AFFECTED GREAT LAKES REGION. OVERALL TEMPS THROUGH THE PERIOD WILL BE AT OR SLIGHTLY BLO NORMAL /NORMAL HIGH TEMPS ON AVERAGE THIS TIME OF YEAR ARE IN THE UPR 70S NORTH TO LOWER 80S SOUTH/. WARMEST DAY MOST LIKELY ON MONDAY AS WARM FRONT LIFTS ACROSS UPPER LAKES RESULTING IN SW SFC WINDS. COLD FRONT MOVES IN MONDAY NIGHT THOUGH...MAKING THIS STAY IN THE WARM SECTOR VERY BRIEF. SHRA/TSRA POSSIBLE AS THESE FRONTAL BOUNDARIES AFFECT THE AREA. ONLY OTHER CHANCE OF RAIN ARRIVES LATER THURSDAY INTO FRIDAY AS ANOTHER SFC TROUGH CROSSES THE REGION. WEAK HIGH PRESSURE AND DRY WEATHER WILL DOMINATE THE WEATHER PATTERN REST OF THE LONG TERM. FIRST FOCUS IN LONGER TERM IS SHORTWAVE PRESSING INTO SCNTRL CANADA ON SUNDAY NIGHT AND SFC LOW/TROUGH MOVING ACROSS NORTHERN PLAINS. SLIGHT H85 TEMP/MOISTURE ADVECTION OVER UPR MICHIGAN AHEAD OF THE WAVE AND SFC TROUGH...BUT INSTABILITY IS PRETTY MINIMAL WITH MUCAPES 1-6KM A FEW HUNDRED J/KG AT BEST...MAINLY OVER FAR WEST LK SUPERIOR CLOSER TO STRONGEST H85-H7 MOISTURE TRANSPORT. FCST SOUNDINGS SHOW INCREASE OF H8-H7 MOISTURE BUT HINT AT DRY AIR BLO AND ABOVE THIS LAYER. WITH LACK OF INSTABILITY AND DEEP MOISTURE AND LARGER SCALE FORCING...THINK COVERAGE TO ANY SHRA/TSRA WILL BE LIMITED SUN NIGHT BUT CANNOT COMPLETELY RULE IT OUT. SEEMS THAT BETTER CHANCES FOR SHRA/TSRA OCCUR ON MONDAY IN THE MORNING DUE TO CLOSER PROXIMITY OF SHORTWAVE/H85 TROUGH AND RESULTING SHARPER WARM AIR ADVECTION AND INCREASING H85 MOISTURE TRANSPORT. EXPECT THIS WARM AIR ADVECTION SHRA/ISOLD TSRA TO SHIFT NORTH BY AFTN ALONG SFC WARM FRONT AND THEN...PROVIDED THERE IS ENOUGH CLEARING OF MORNING CLOUDS/SHRA/TSRA...THERE SHOULD BE PERIOD OF BUILDING INSTABILITY DURING PEAK HEATING AS TEMPS WARM INTO THE UPR 70S/LWR 80S. MLCAPES TOP OUT AROUND 800-1200J/KG...HIGHEST ALONG WI BORDER. DEEP LAYER SHEAR INCREASES IN WARM SECTOR OUT AHEAD OF COLD FRONT TO 30-40 KTS AS SHORTWAVE CROSSES NORTHERN ONTARIO AND ADJACENT LK SUPERIOR. SOUNDINGS SHOW A BIT OF CAPPING AROUND H8 AND THIS ADDS UNCERTAINTY TO INITIATION. BASED ON CAPE AND SHEAR BALANCE...THERE SEEMS TO BE AT LEAST SMALL POTENTIAL FOR ISOLD SVR STORMS. SUPERCELLS POSSIBLE AS WINDS SHOW SUFFICIENT VEERING WITH HEIGHT. HAIL/WIND PRIMARY HAZARDS WITH LOWER WBZERO HEIGHTS AROUND 11KFT AND DCAPE UP TO 1000J/KG. ALL THIS IS CONDITIONAL ON HOW MUCH INSTABILITY CAN MATERIALIZE. SINCE SPC DAY 3 DID INDICATE SEE TEXT OVER THE AREA...THINK IT IS WORTH AN HWO MENTION. COLD FRONT BLOWS THROUGH CWA PRETTY QUICKLY MONDAY EVENING/EARLY OVERNIGHT. TRENDED TOWARD LOWER POPS 6Z-12Z ON TUESDAY WITH DRYING NOTED IN SOUNDINGS AND GFS/ECMWF SHOWING LITTLE IF ANY QPF IN THAT TIME FRAME THE LAST FEW MODEL RUNS. IN WAKE OF THE COLD FRONT ON TUESDAY...COULD END UP WITH NEARLY CARBON COPY OF TODAY...COOL TEMPS ALONG LK SUPERIOR/HIGHER SWIM RISK AND READINGS INTO LOWER 70S TOWARD WI BORDER. CUT GUIDANCE TEMPS FOR TUESDAY NIGHT WITH HIGH CENTER OVERHEAD. FAVORED COLD SPOTS OVER MAINLY WEST COULD REACH TO AROUND 40 DEGREES. STAYS QUIET THROUGH WEDNESDAY NIGHT AS HIGH PRESSURE SLOWLY RETREATS. NEXT CHANCE OF RAIN RETURNS THURSDAY INTO FRIDAY. MODELS HAVING TOUGH TIME HANDLING SHORTWAVE TROUGH PUSHING THROUGH IN WNW FLOW ALOFT. LATEST GFS AND ECMWF WOULD INDICATE SHORTWAVE PASSAGE THURSDAY OR THURSDAY NIGHT. BLEND OF CONSENSUS SHOWS SLIGHT CHANCE/LOW CHANCE POPS AS ANOTHER COLD FRONT CROSSES THE AREA TIED TO THE WAVE. SATURDAY LOOKING PRETTY COOL YET AGAIN BEHIND THIS COLD FRONT. PROBABLY WILL END UP SIMILAR TO WHAT IS OCCURRING TODAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 139 PM EDT SAT JUL 20 2013 VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD AS HIGH PRESSURE GRADUALLY BUILDS INTO THE REGION. NRLY WINDS WILL DIMINISH THIS EVENING WITH THE LOSS OF DAYTIME HEATING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 419 PM EDT SAT JUL 20 2013 AS HIGH PRESSURE BUILDS INTO THE NORTHERN GREAT LAKES...WINDS WILL DIMINISH THIS EVENING TO LESS THAN 20 KNOTS. SRLY WINDS WILL INCREASE TO AROUND 20 KNOTS AHEAD OF A LOW PRESSURE TROUGH MOVING THROUGH THE AREA ON MONDAY. NORTH TO NORTHWEST WINDS WILL THEN INCREASE TO 20 TO 30 KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND A COLD FRONT MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN BELOW 20 KNOTS THROUGH THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT SAT JUL 20 2013 .SYNOPSIS... ISSUED AT 330 AM EDT SAT JUL 20 2013 FAIR WEATHER WILL RETURN THIS WEEKEND WITH SEASONABLE TEMPERATURES AND IT WILL BE MUCH LESS HUMID. HIGHS WILL BE CLOSER TO NORMALS FOR THIS TIME OF YEAR WITH LOWER TO MIDDLE 80S TODAY AND AROUND 80 ON SUNDAY. THE NEXT CHANCE OF SHOWERS AND STORMS WILL COME LATE SUNDAY NIGHT AND MONDAY. && .SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON) ISSUED AT 330 AM EDT SAT JUL 20 2013 HIGH PRESSURE WILL BRING FAIR WEATHER THIS WEEKEND WITH SEASONABLE TEMPERATURES. HIGH TEMPERATURES TODAY WILL REACH THE LOWER TO MIDDLE 80S AND UPPER 70S TO LOWER 80S ON SUNDAY. A LOW PRESSURE SYSTEM WILL BRING THE NEXT CHC FOR SHOWERS AND TSTORMS AS EARLY AS LATE SUNDAY NIGHT WITH A LITTLE BETTER CHC FOR PCPN ON MONDAY AS AN UPPER LEVEL TROF AXIS MOVES ACROSS THE LOWER GREAT LAKES REGION. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 330 AM EDT SAT JUL 20 2013 && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 726 PM EDT FRI JUL 19 2013 THE BIG QUESTION IS DOES A LINE OF STORMS FORM JUST AHEAD OF THE FRONT OR NOT? CURRENTLY SCATTERED STORMS ARE TRYING TO ORGANIZE NEAR MBL...WHICH IS JUST AHEAD OF THE COLD FRONT. THE TIMING TOOL TAKES THAT TO MKG BY 0430Z AND TO THE I-94 TAF SITES BY 11Z. THIS SEEMS TO SLOW... THE LATEST HRRR REDEVELOPS STORMS OVER SOUTHERN LAKE MICHIGAN BY 01Z AND HEADS THOSE STORMS OUT OF THE CWA BY 04Z. SINCE THERE IS A JET SPEED MAX THAT COMES THROUGH THE AREA IN THE 03Z TIME FRAME... IT WOULD SEEM THERE IS A GOOD CHANCE THE STORMS COULD YET BETTER ORGANIZE. SO NOT HAVING ANYTHING SOLID TO TRACK INTO THE TAF SITES...I KEPT THE VCTS GOING 09Z AT MOST OF THE TAF SITES. BEHIND THE FRONT SKIES WILL CLEAR SO MOST OF SATURDAY SHOULD BE CLEAR WITH A NORTHWEST WIND AROUND 10 KNOTS. && .MARINE... ISSUED AT 330 AM EDT SAT JUL 20 2013 WAVE HEIGHTS WILL RAMP BACK UP LATER TODAY AS NNW TO NORTH WINDS INCREASE LATE THIS MORNING/AFTN. WE WILL HOIST A SMALL CRAFT ADVISORY TO COVER THIS FROM LATE THIS MORNING THROUGH THE LATE EVENING HOURS TONIGHT. A BEACH HAZARD STATEMENT HAS ALSO BEEN ISSUED DETAILING THE HIGH SWIM HAZARD RISK THAT IS IN PLAY AGAIN TODAY. && .HYDROLOGY... ISSUED AT 330 AM EDT SAT JUL 20 2013 NO HYDRO ISSUES WITH HIGH PRESSURE BUILDING IN THIS WEEKEND BRINGING FAIR AND DRY WX. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...BEACH HAZARDS STATEMENT 11 AM TODAY THROUGH LATE THIS EVENING FOR MIZ037-043-050-056-064-071. LM...SMALL CRAFT ADVISORY 11 AM TODAY THROUGH LATE THIS EVENING FOR LMZ844>849. && $$ SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MJS AVIATION...WDM HYDROLOGY...LAURENS MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
932 AM CDT Sat Jul 20 2013 .UPDATE... Issued at 931 AM CDT SAT JUL 20 2013 Scattered convection has developed this morning along a lingering frontal boundary surface boundary near US 50, with additional storms further north near an elevated boundary near 850 hPa. Winds aloft are quite weak, so this activity will be pulse in nature and slow to drift eastward. Latest RAP and NAM suggest that this boundary, both at the surface and aloft, may maintain its definition and nudge northward slightly through the afternoon. This may keep rain chances going into the afternoon for areas near and south of the Missouri River. Trying to pinpoint location and timing of this activity is quite difficult, so the forecast was adjusted to account for the current location of showers and storms, blending into broader low- chance PoPs through the afternoon. && .SHORT TERM...(Today through Sunday) Issued at 316 AM CDT SAT JUL 20 2013 The main forecast challenge for today will be precipitation chances along a weak frontal boundary and pre-frontal trough stretching over the forecast area. Convection-allowing models are hinting at the possibility for re-development along the pre-frontal trough between daybreak and mid-morning; however, this could occur on the southern edge or even further south of the CWA, and should be fairly isolated in nature. With the main boundary stalling south of I-70 today, the main question will be whether afternoon storm development will occur along the front. With only weak low-level convergence and a stout capping inversion, afternoon convection still looks fairly unlikely. The further south the surface boundary can sag this afternoon, the better the chances will be for precipitation, since this would keep the front a bit further from the midlevel thermal axis and should result in a weaker cap... so have kept the higher PoPs confined to areas south of I-70 for the late afternoon and early evening hours. After this boundary becomes a bit more diffuse and continues to filter southward out of the CWA, the main chances for precipitation will come with a shortwave trough dropping southeast out of central SD. Convection will develop during the afternoon or evening hours in central SD and into eastern Nebraska, and will push southeast while continuing to develop across the forecast area late tonight and into Sunday. The severe weather potential still looks low with weak low- level shear, moderate instability but lackluster lift, and unimpressive downdraft CAPE. Although PWATs are fairly high and the chance for measurable precipitation looks the highest in quite a while for Sunday, have kept precipitation totals less than an inch through the period due to a decent southeastward progression of the wave and disintegration of the surface boundary. Temperatures today will be held down slightly by scattered cloud cover and weak mixing, but should still reach the lower 90s on both sides of the frontal boundary. Widespread cloud cover and scattered precipitation will keep temperatures cooler on Sunday, and should hold highs mainly in the 80s across the region. .LONG TERM...(Monday through Friday) Issued at 316 AM CDT SAT JUL 20 2013 Previous forecast philosophy remains on track with regards to extended forecast as operational models continue to show good agreement with the general upper pattern. Persistent northwest flow aloft is expected through much of the work week, with a general flattening of the upper trough by the end of the week. This pattern will result in continued chances for precipitation and temperatures near or slightly below seasonal levels. Several upper disturbances are projected to move through the region, and with a surface frontal boundary residing in close proximity to the forecast area, sufficient conditions will help promote the development of scattered thunderstorms. The exact evolution, coverage, timing, and rainfall amounts from convective episodes are still somewhat ill-resolved with this period still several days away and the dependency of subsequent days of convection and its effect on surface feature positions. Beyond the inherent uncertainty with this type of setup, confidence continues to increase that much of the forecast area will see the potential for multiple rounds of precipitation through the upcoming workweek. Maximum temperatures will progressively cool, with highs in the 80s in most locations by midweek. && .AVIATION...(For the 12Z TAFS through 12Z Sunday Morning) Issued at 637 AM CDT SAT JUL 20 2013 A few showers and thunderstorms will impact portions of west central Missouri and eastern Kansas this morning, but should diminish over the next several hours and remain south of all TAF sites. Otherwise, mainly VFR conditions are expected today with a possibility for additional storm development in central KS/MO this afternoon, and a high probability of widespread storms around 12z Sunday morning. A frontal boundary will also stall around or south of I-70 today, which will keep winds generally light but variable in direction. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...Hawblitzel SHORT TERM...Laflin LONG TERM...Blair AVIATION...Laflin
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
422 PM MDT SAT JUL 20 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY... MADE A QUICK UPDATE TO CHANGE AFTERNOON WX TO COVERAGE AND INCREASE POPS. A COUPLE OF STRONG STORMS HAVE POPPED UP WITH REPORTS OF HEAVY RAIN...SMALL HAIL...AND GUSTY WIND. SCT PREVIOUS DISCUSSION... CONVECTIVE ACTIVITY THIS AFTERNOON WILL CONTINUE TO DEVELOP OVER THE NEXT COUPLE OF HOURS BUT SHOULD DIMINISH PRETTY QUICK WITHOUT THE SHEAR IN PLACE. HRRR MODEL SHOWING JUST SCATTERED ACTIVITY AT BEST OVER THE NORTHEASTERN HALF OF THE CWA THIS EVENING. WITH AN UPPER TROUGH OVER THE EASTERN STATES AND A RIDGE TO OUR WEST...THE AREA IS UNDER A WEST-NORTHWEST FLOW. A DISTURBANCE...BOTH AT THE SURFACE AND ALOFT MOVES INTO SOUTHERN SASK LATER TONIGHT...KEEPING SHOWERS/THUNDERSTORMS GOING OVERNIGHT MAINLY TO THE NORTHEAST ZONES. SUNDAY...DISTURBANCE MOVES SOUTHEAST AND THROUGH THE CWA BRINGING AN INCREASE IN WEST WINDS DURING THE AFTERNOON. THEY SHOULD BE STRONG ENOUGH TO CAUSE PROBLEMS FOR FORT PECK LAKE FROM NOON UNTIL 9 PM...SO ISSUED A LAKE WIND ADVISORY. ON MONDAY...BACKDOOR FRONT THAT LIES NW TO SE ACROSS MONTANA SUNDAY NIGHT HELPS TO FIRE UP THUNDERSTORMS AS A VORT MAX MOVES IN FROM THE WEST. ACTIVITY MOVES IN FROM THE WEST WITH MORE ACTIVITY EXPECTED DURING THE EVENING. TFJ .LONG TERM...MONDAY NIGHT THROUGH SATURDAY... AN UPPER LEVEL RIDGE IN THE WEST AND A PERSISTENT UPPER TROUGH CENTERED OVER NORTHERN QUEBEC WILL MAINTAIN A NORTHWEST FLOW OVER NORTHEAST MONTANA THROUGH MOST OF THE PERIOD. WEAK EMBEDDED DISTURBANCES IN THE UPPER FLOW WILL BRING ISOLATED TO SCATTERED THUNDERSTORMS TO THE REGION THROUGHOUT THE PERIOD. MONDAY EVENING AND OVERNIGHT GFS SENDS A DISTURBANCE FLOWING ALONG THE STATIONARY BOUNDARY THAT WILL INITIATE THUNDERSTORMS ACROSS NEMONT. WITH SOME AGREEMENT FROM THE 00Z EC...WENT AHEAD AND ADJUSTED POPS TO CHANCE. TUESDAY THROUGH SATURDAY THE FLUCTUATING STATIONARY BOUNDARY AND WEAK DISTURBANCES WILL GENERATE A FEW STORMS EACH DAY. THIS IS REFLECTED IN THE INHERITED GRIDS AND NO CHANGES ARE PLANNED HERE. SCT SYNOPTIC SET UP... A LARGE HIGH PRESSURE HEAT DOME IS CENTERED OVER THE LOWER INTER-MOUNTAIN WEST. A RIDGE SPUR RUNS NORTH OF THIS DOME INTO BRITISH COLUMBIA. A LARGE TROUGH EXTENDS FROM THE NORTHERN US PLAINS INTO MANITOBA AND UP THROUGH NUNAVUT. NORTHEAST MONTANA LIES BETWEEN THESE TWO FEATURES IN A ZONAL TO NORTHWEST FLOW PATTERN. ANOTHER LARGE TROUGH LIES OFF THE COAST OF BRITISH COLUMBIA. MONDAY NIGHT THROUGH THURSDAY NIGHT... NORTHWEST FLOW WILL END UP ALLOWING HIGH POP CHANCE ACROSS THE NORTHEAST DRYING TOWARD THE SOUTHWEST. THIS GRADIENT WILL BEGIN A BIT MORE SHARP MONDAY NIGHT BUT WILL SLOWLY DIFFUSE OUT TOWARD THURSDAY NIGHT AS JETS AND SHORTWAVES BECOME MORE FUZZY IN TIME. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DO EXIST ALMOST EVERY PERIOD. FRIDAY ONWARD... THE PATTERN WILL BECOME A LITTLE MORE PROGRESSIVE AS THE RIDGE TO THE WEST SETTLES OVER THE MONTANA HIGH PLAINS. THIS SHOULD EDGE TEMPERATURES UP BUT POPS WILL PROBABLY REMAIN AS THE ATMOSPHERE BECOMES MORE DESTABILIZED. HOWEVER... QPF IS EXPECTED TO LOWER AS PLANTS BEGIN TO STRESS FROM PROGRESSIVELY DRIER HOTTER DAYS AND SOILS FOLLOWED BY THE SURFACE LAYER OF THE ATMOSPHERE DRY OUT. GAH && .AVIATION... GENERALLY VFR. HOWEVER A WEAK UPPER LEVEL DISTURBANCE FLOWING OVER A STATIONARY SURFACE BOUNDARY WILL INITIATE ISOLATED TO SCATTERED AFTERNOON/EVENING THUNDERSTORMS THAT COULD AFFECT ANY OF THE TAF SITES. SCT && .GLASGOW WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY FROM NOON TO 9 PM MDT SUNDAY FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
238 PM MDT SAT JUL 20 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY... CONVECTIVE ACTIVITY THIS AFTERNOON WILL CONTINUE TO DEVELOP OVER THE NEXT COUPLE OF HOURS BUT SHOULD DIMINISH PRETTY QUICK WITHOUT THE SHEAR IN PLACE. HRRR MODEL SHOWING JUST SCATTERED ACTIVITY AT BEST OVER THE NORTHEASTERN HALF OF THE CWA THIS EVENING. WITH AN UPPER TROUGH OVER THE EASTERN STATES AND A RIDGE TO OUR WEST...THE AREA IS UNDER A WEST-NORTHWEST FLOW. A DISTURBANCE...BOTH AT THE SURFACE AND ALOFT MOVES INTO SOUTHERN SASK LATER TONIGHT...KEEPING SHOWERS/THUNDERSTORMS GOING OVERNIGHT MAINLY TO THE NORTHEAST ZONES. SUNDAY...DISTURBANCE MOVES SOUTHEAST AND THROUGH THE CWA BRINGING AN INCREASE IN WEST WINDS DURING THE AFTERNOON. THEY SHOULD BE STRONG ENOUGH TO CAUSE PROBLEMS FOR FORT PECK LAKE FROM NOON UNTIL 9 PM...SO ISSUED A LAKE WIND ADVISORY. ON MONDAY...BACKDOOR FRONT THAT LIES NW TO SE ACROSS MONTANA SUNDAY NIGHT HELPS TO FIRE UP THUNDERSTORMS AS A VORT MAX MOVES IN FROM THE WEST. ACTIVITY MOVES IN FROM THE WEST WITH MORE ACTIVITY EXPECTED DURING THE EVENING. TFJ .LONG TERM...MONDAY NIGHT THROUGH SATURDAY... AN UPPER LEVEL RIDGE IN THE WEST AND A PERSISTENT UPPER TROUGH CENTERED OVER NORTHERN QUEBEC WILL MAINTAIN A NORTHWEST FLOW OVER NORTHEAST MONTANA THROUGH MOST OF THE PERIOD. WEAK EMBEDDED DISTURBANCES IN THE UPPER FLOW WILL BRING ISOLATED TO SCATTERED THUNDERSTORMS TO THE REGION THROUGHOUT THE PERIOD. MONDAY EVENING AND OVERNIGHT GFS SENDS A DISTURBANCE FLOWING ALONG THE STATIONARY BOUNDARY THAT WILL INITIATE THUNDERSTORMS ACROSS NEMONT. WITH SOME AGREEMENT FROM THE 00Z EC...WENT AHEAD AND ADJUSTED POPS TO CHANCE. TUESDAY THROUGH SATURDAY THE FLUCTUATING STATIONARY BOUNDARY AND WEAK DISTURBANCES WILL GENERATE A FEW STORMS EACH DAY. THIS IS REFLECTED IN THE INHERITED GRIDS AND NO CHANGES ARE PLANNED HERE. SCT SYNOPTIC SET UP... A LARGE HIGH PRESSURE HEAT DOME IS CENTERED OVER THE LOWER INTER-MOUNTAIN WEST. A RIDGE SPUR RUNS NORTH OF THIS DOME INTO BRITISH COLUMBIA. A LARGE TROUGH EXTENDS FROM THE NORTHERN US PLAINS INTO MANITOBA AND UP THROUGH NUNAVUT. NORTHEAST MONTANA LIES BETWEEN THESE TWO FEATURES IN A ZONAL TO NORTHWEST FLOW PATTERN. ANOTHER LARGE TROUGH LIES OFF THE COAST OF BRITISH COLUMBIA. MONDAY NIGHT THROUGH THURSDAY NIGHT... NORTHWEST FLOW WILL END UP ALLOWING HIGH POP CHANCE ACROSS THE NORTHEAST DRYING TOWARD THE SOUTHWEST. THIS GRADIENT WILL BEGIN A BIT MORE SHARP MONDAY NIGHT BUT WILL SLOWLY DIFFUSE OUT TOWARD THURSDAY NIGHT AS JETS AND SHORTWAVES BECOME MORE FUZZY IN TIME. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DO EXIST ALMOST EVERY PERIOD. FRIDAY ONWARD... THE PATTERN WILL BECOME A LITTLE MORE PROGRESSIVE AS THE RIDGE TO THE WEST SETTLES OVER THE MONTANA HIGH PLAINS. THIS SHOULD EDGE TEMPERATURES UP BUT POPS WILL PROBABLY REMAIN AS THE ATMOSPHERE BECOMES MORE DESTABILIZED. HOWEVER... QPF IS EXPECTED TO LOWER AS PLANTS BEGIN TO STRESS FROM PROGRESSIVELY DRIER HOTTER DAYS AND SOILS FOLLOWED BY THE SURFACE LAYER OF THE ATMOSPHERE DRY OUT. GAH && .AVIATION... GENERALLY VFR. HOWEVER A WEAK UPPER LEVEL DISTURBANCE FLOWING OVER A STATIONARY SURFACE BOUNDARY WILL INITIATE ISOLATED TO SCATTERED AFTERNOON/EVENING THUNDERSTORMS THAT COULD AFFECT ANY OF THE TAF SITES. SCT && .GLASGOW WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY FROM NOON TO 9 PM MDT SUNDAY FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
926 PM CDT SUN JUL 21 2013 .SYNOPSIS... ISSUED AT 333 PM CDT SUN JUL 21 2013 H5 ANALYSIS FROM THIS MORNING...HAS TWO AREAS OF HIGH PRESSURE ALOFT...THE FIRST OVER NEVADA...AND A SECOND OFF THE CAROLINA COAST. IN BETWEEN...A TROUGH OF LOW PRESSURE EXTENDED ACROSS THE SRN PLAINS FROM KANSAS INTO NERN TX. ACROSS THE NRN TIER OF STATES...INCLUDING THE CENTRAL AND NRN PLAINS...BROAD WEST NORTHWESTERLY AND WESTERLY FLOW EXTENDED FROM THE PACIFIC NW...INTO THE CENTRAL AND NRN PLAINS...EWD INTO THE MID ATLANTIC AND NEW ENGLAND. UPSTREAM OF THE CENTRAL PLAINS...A DECENT SHORTWAVE WAS NOTED OVER SRN ALBERTA...AND A SECOND STRONGER WAVE OVER NWRN PORTIONS OF BRITISH COLUMBIA. AT THE SURFACE...A CONVECTIVE INDUCED MESO HIGH WAS LOCATED OVER SWRN NEBRASKA...WITH DECENT SRLY WINDS NOTED ACROSS THE PANHANDLE ATTM. AS OF 3 PM CDT...TEMPERATURES RANGED FROM 84 AT AINWSWORTH...TO 90 AT IMPERIAL. && .UPDATE... ISSUED AT 921 PM CDT SUN JUL 21 2013 THE HRRR SHOWS THE STORMS ACROSS NW NEB FILLING IN AND BECOMING A LINE OF TSTMS WHICH SWEEP THE FCST AREA OVERNIGHT. THIS IS PROBABLY OVERDONE. THE RAP SHOWS NO STORMS AT ALL BUT INDICATES A 20 TO 30 KT LOW LEVEL JET RUNNING DUE NORTH UP THROUGH WRN NEB TONIGHT. PWAT SHOULD INCREASE TO 1.25 INCHES AND MAYBE MORE ACCORDING TO THE RAP. SO THE FORECAST HAS BEEN UPDATED FOR SCATTERED TSTMS WHICH IS A COMPROMISE OF THE HRRR AND RAP MODELS. NOTE THE 18Z NAM SHOWED ISOLATED STORMS MOVING SOUTHEAST TONIGHT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 333 PM CDT SUN JUL 21 2013 WEAK WAVE IS MOVING ACROSS EAST CENTRAL WYOMING THIS AFTERNOON. THIS WAVE WILL BE THE FOCUS FOR SOME ISOLATED THUNDERSTORMS. LACKING SOME MOISTURE AS DEW PTS IN THE LOWER TO MID 50S. LOW LEVEL JET ALONG THE FRONT RANGE TONIGHT AND WILL AID IN THUNDERSTORM DEVELOPMENT. ATMOSPHERE TOOK A BEATING LAST NIGHT AND EARLY THIS MORNING...SO CONFIDENCE IS LOW ON HOW WIDESPREAD THE COVERAGE WILL BE...HOWEVER SEVERAL REMNANT BOUNDARIES COULD HELP TO SPARK DEVELOPMENT. SINCE THERE IS NOT MUCH OF A CU FIELD...AND ONLY ONE CELL HAS GOTTEN GOING OVER WYOMING...EXPECT COVERAGE TO BE ISOLD. AS FOR TEMPS...THEY SHOULD COOL BACK INTO THE 60S...ALTHOUGH LOCALLY IN THE WEST A BRIEF DIP BELOW 60 IS POSSIBLE. TOMORROW RIDGE REMAINS DOMINATE TO THE SOUTHWEST...WITH MOSTLY SUNNY SKIES THROUGH MOST OF THE DAY. HIGHS INTO THE LOWER/MID 90S ACROSS THE SW TO THE UPPER 80S ACROSS N CENTRAL. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 333 PM CDT SUN JUL 21 2013 MID RANGE...MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING CHALLENGE CONTINUES TO BE PRECIPITATION CHANCES...AS TIMING AND LOCATION REMAIN PROBLEMATIC GIVEN THE NORTHWESTERLY FLOW. FOR MONDAY NIGHT...MID LEVEL HTS WILL BEGIN TO INCREASE AS HIGH PRESSURE ALOFT BUILDS EAST OF THE DESERT SOUTHWEST. INCREASED MID LEVEL WAA WILL RESULT...LEADING TO INCREASED POPS MONDAY NIGHT INTO EARLY TUESDAY. WILL KEEP POPS AS SLIGHTS ATTM...AS DECENT JET SUPPORT IS FOCUSED EAST OF THE AREA. A SECONDARY AREA OF MID LEVEL WAA WILL TRACK ACROSS THE CWA FROM NW TO SE ON TUESDAY INTO TUESDAY EVENING. WILL HOLD ONTO SLIGHT CHANCES FOR PCPN SINCE THE BEST JET SUPPORT REMAINS EAST OF THE AREA. BY WEDNESDAY AFTERNOON...BOTH THE NAM AND GFS FORCE A DECENT SHORTWAVE INTO WRN NEBRASKA LATE IN THE DAY...LIFTING THIS EAST INTO WEDNESDAY NIGHT. WILL START POPS OFF LOW IN THE WEST...AS BETTER CHANCES WILL ARRIVE WEDNESDAY NIGHT AS THE FORECAST AREA IS IN THE RIGHT REAR QUAD OF THE EXITING JET. LONG RANGE...WEDNESDAY NIGHT THROUGH SUNDAY...ACTIVE WESTERLY AND NORTHWESTERLY FLOW ALOFT WILL CONTINUE ACROSS THE CENTRAL AND NORTHERN PLAINS INTO THE EXTENDED PERIODS. ATTM...THE BEST CHANCES FOR RAIN APPEAR TO LIE ON WEDNESDAY NIGHT AND FRIDAY NIGHT AS THE FORECAST AREA IS IN A FAVORABLE EXIT REGION OF THE H300 JET. HAVE INCREASED POPS INTO THE 50 PERCENT RANGE FOR WEDNESDAY NIGHT AND THURSDAY AND WILL KEEP CHANCE POPS GOING INTO THURSDAY NIGHT. THE EXTENSION OF POPS INTO THURSDAY NIGHT...IS TO ACCOMMODATE THE LATEST ECMWF WHICH IS 12 HRS SLOWER THAN THE LATEST GFS SOLN. TEMPERATURES FOR THE WEEK WILL COOL BACK INTO THE 80S...THANKS TO EXPECTED CLOUD COVER AND SERLY AND ERLY UPSLOPE WINDS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 636 PM CDT SUN JUL 21 2013 VFR IS EXPECTED TONIGHT AND MONDAY. A COLD FRONT...CURRENTLY MOVING THROUGH ND...SWRN MT AND NERN WY...WILL MOVE THROUGH THE FCST AREA OVERNIGHT AND BECOME STATIONARY ACROSS SWRN NEB MONDAY AFTN. THE FRONT COULD BE THE FOCUS FOR ISOLATED STRONG OR SEVERE TSTMS AFTER 21Z MONDAY FROM ROUGHLY KBBW TO KLBF...KOGA AND KIML. NOTE ISOLATED TSTMS MAY FORM ALONG THE FRONT TONIGHT AS IT MOVES THROUGH THE FCST AREA BUT THESE STORMS SHOULD BE VERY MARGINAL. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...MASEK LONG TERM...CLB AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
256 PM CDT SAT JUL 20 2013 .SYNOPSIS... ISSUED AT 253 PM CDT SAT JUL 20 2013 THE H5 ANALYSIS THIS MORNING...HAS AN ACTIVE NW FLOW PATTERN ACROSS THE NRN CONUS. HIGH PRESSURE WAS ANCHORED ACROSS THE CENTRAL VALLEY OF CA...WITH A PERSISTENT BERMUDA HIGH PRESENT ACROSS THE WESTERN ATLANTIC. A BROAD TROUGH OF LOW PRESSURE EXTENDED FROM NRN QUEBEC INTO THE MID ATLANTIC STATES. ACROSS THE NRN ROCKIES AND CENTRAL PLAINS...NUMEROUS SHORTWAVES WERE EMBEDDED IN THE NWRLY FLOW. ONE OVER NWRN WYOMING...AND A SECOND OVER THE IDAHO PANHANDLE. ANOTHER DISTURBANCE WAS NOTED OVER NWRN IA AS WELL. AT THE SURFACE...SHOWERS AND THUNDERSTORMS HAVE CONTINUED ACROSS NORTHERN NEBRASKA THIS MORNING AND EARLY THIS AFTERNOON...ALONG A WEAK SURFACE BOUNDARY. TEMPERATURES AS OF 2 PM CDT RANGED FROM 68 IN RAIN COOLED AIR AT ONEILL...TO 87 AT OGALLALA...IMPERIAL AND NORTH PLATTE. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 253 PM CDT SAT JUL 20 2013 SCATTERED THUNDERSTORMS THIS AFTERNOON ARE EXPECTED TO DEVELOP OVER THE NEBRASKA PANHANDLE AND NORTHWEST NEBRASKA AND COALESCE INTO A CONVECTIVE SYSTEM BY EARLY THIS EVENING. WITH THE DEEP SHEAR VECTORS DIAGONAL TO THE LOW LEVEL BOUNDARY...IT APPEARS TO FAVOR THE DEVELOPMENT OF A LINEAR CONVECTIVE SYSTEM. ACCORDING TO THE SHORT RANGE HRRR AND RAP13...THE SYSTEM WILL AFFECT A LARGE PART OF THE SANDHILLS AND SOUTHWEST NEBRASKA BY 01Z AND FINALLY CLEARING CENTRAL NEBRASKA BY 09Z. THEY DO INDICATE SOME LINGERING SHOWERS AND THUNDERSTORMS EVEN INTO EARLY SUNDAY. INSTABILITY CONTINUES OVER WESTERN NEBRASKA SUNDAY AND THERE IS A CHANCE OF ANOTHER CONVECTIVE SYSTEM DEVELOPING IN SOUTH DAKOTA AND NORTHWEST NEBRASKA LATE SUNDAY MORNING OR EARLY AFTERNOON...THEN CROSSING WESTERN NEBRASKA THROUGH THE AFTERNOON. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 253 PM CDT SAT JUL 20 2013 MID RANGE...SUNDAY NIGHT THROUGH TUESDAY...A FAIRLY ACTIVE PATTERN WILL CONTINUE INTO TUESDAY...THANKS TO NWLY FLOW AND THE PRESENCE OF EMBEDDED SHORTWAVES WITHIN THAT FLOW. BEGINNING SUNDAY NIGHT...ANOTHER UPPER LEVEL DISTURBANCE WILL TRACK FROM THE CENTRAL AND NORTHERN ROCKIES...ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. CONVECTION WILL BE ONGOING BY SUNDAY AFTERNOON AND IS EXPECTED TO IMPACT MOST OF THE FORECAST AREA DURING THE EVENING AND OVERNIGHT HOURS. ATTM...WILL PAINT THE HIGHEST POPS IN THE CENTRAL AND SOUTHWESTERN CWA...AS THESE LOCATIONS WILL SEE THE BEST DEEP LAYER SHEAR OF 30 TO 40 KTS. SHEAR IN THE NERN ZONES WILL RUN 10 TO 20 KTS SUNDAY EVENING...SO ANY TSRAS IN THESE AREAS WILL BE FEW AND FAR BETWEEN. WILL CONTINUE MENTION OF THUNDERSTORMS IN THE FORECAST OVERNIGHT IN THE SOUTHWESTERN ZONES AS THERE ARE INDICATIONS OF THE DEVELOPMENT OF A LOW LEVEL JET...WHICH BECOMES FOCUSED ACROSS SWRN AND CENTRAL NEBRASKA OVERNIGHT SUNDAY NIGHT. CONVECTION ALONG WITH THE EXITING DISTURBANCE...WILL FORCE A FRONTAL BOUNDARY THROUGH THE FORECAST AREA ON MONDAY...STALLING THIS FEATURE ACROSS CENTRAL AND EASTERN NEBRASKA MONDAY EVENING. ONCE AGAIN...UPPER LEVEL ENERGY WILL ENTER THE CENTRAL PLAINS FROM THE ROCKIES LATE IN THE DAY MONDAY...LEADING TO THE DEVELOPMENT OF THUNDERSTORMS. THERE IS SOME DISAGREEMENT AS TO WHERE THE UPPER LEVEL ENERGY WILL TRACK DURING THIS PERIOD SO CONFIDENCE IN LOCATION OF POPS IS LACKING ATTM. DECIDED TO CONFINE POPS INVOF OF THE FRONTAL BOUNDARY...IE...EASTERN CWA FOR MONDAY NIGHT. ON TUESDAY...EASTERLY WINDS WILL BECOME SOUTHERLY BY AFTERNOON AS HIGH PRESSURE DRIFTS EAST INTO THE UPPER MIDWEST. THE FRONTAL BOUNDARY WILL WASH OUT WHILE NORTHWESTERLY FLOW ALOFT CONTINUES. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL TRACK ACROSS THE REGION TUESDAY AFTERNOON AND TUESDAY NIGHT AS ANOTHER UPPER LEVEL DISTURBANCE TRACKS FROM THE CENTRAL AND NORTHERN ROCKIES ONTO THE CENTRAL PLAINS. LONG RANGE...TUESDAY NIGHT THROUGH SATURDAY...A FAIRLY ACTIVE PATTERN WILL CONTINUE INTO THE EXTENDED PERIODS WITH ABUNDANT LOW LEVEL MOISTURE AND PERSISTENT WESTERLY AND NORTHWESTERLY FLOW ALOFT. NUMEROUS SHORTWAVES WILL TRACK ACROSS THE CENTRAL ROCKIES ACROSS THE CENTRAL PLAINS THROUGH THE PERIOD...LEADING TO A GOOD CHANCE FOR PRECIPITATION DURING THE PERIOD. TEMPERATURES WILL BE SEASONAL WITH HIGHS IN THE 80S AND LOWS IN THE UPPER 50S AND LOWER 60S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 253 PM CDT SAT JUL 20 2013 SCATTERED THUNDERSTORMS ARE EXPECTED THIS EVENING OVER A LARGE PART OF CENTRAL AND WESTERN NEBRASKA. WITH STORMS FORMING INTO A LINE LATE THIS AFTERNOON...THE PROBABILITY OF THUNDERSTORMS AT ANY ONE SITE IS LIKELY TO BE 50 PERCENT OR HIGHER. AS A RESULT THUNDER IS IN THE TERMINAL FORECASTS FOR VTN AND LBF THIS EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CLB SHORT TERM...SPRINGER LONG TERM...CLB AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1248 PM CDT SAT JUL 20 2013 .UPDATE... ISSUED AT 1247 PM CDT SAT JUL 20 2013 UPDATED HWO IS OUT AND HAS OUR THOUGHTS THIS AFTN. ADDITIONAL TSTMS COULD DEVELOP AT ANY TIME. WE/VE BEEN WATCHING A DECENT STORM LEAVE WEBSTER FOR THAYER COUNTY WITH SOME TORRENTIAL RAINFALL. THE TSTM CLUSTERS OVER THE PANHANDLE AND SANDHILLS ARE EXPECTED TO INCREASE IN COVERAGE/INTENSITY AND THAT ACTIVITY SHOULD ARRIVE HERE TNGT. UPDATE ISSUED AT 1107 AM CDT SAT JUL 20 2013 THE INITIAL COMPOSITE OUTFLOW BOUNDARY CONTS DROPPING STEADILY S AT 22 KTS AND WILL ARRIVE AT THE KS BORDER AROUND 1215 PM. SCT SHWRS WERE DEVELOPING ATOP THIS OUTFLOW AND THIS POTENTIAL IS EXPECTED TO CONT DESPITE THE SEEMINGLY UNFAVORABLE ENVIRONMENT. VIS SATPIX SHOWED ANOTHER OUTFLOW BOUNDARY /FROM THE TSTMS HEADING INTO NE NEB/ THAT WILL MOVE INTO THE NRN FRINGE OF THE FCST AREA SHORTLY /ORD-GREELEY/. THE OAX SOUNDING WAS VERY DRY BELOW 700 MB FROM OVERNGT SUBSIDENCE. HOWEVER...THE OUTFLOW IS CLEARLY ENOUGH TO INITIATE SHWRS WITH EMBEDDED THUNDER. SO THIS REALLY COMPLICATES THE SITUATION TODAY...AND LOWERS CONFIDENCE IN HOW THINGS WILL DEVELOP/EVOLVE. REGIONAL 88D WIND PROFILES SHOW DEEP E-NE FLOW UP TO 9K FT...WHICH WOULD BE ENUF TO INITIATE SHWRS/THUNDER BASED ON THE OAX SOUNDING. GLD AND TOP HAVE MORE SHALLOW S FLOW...WHERE MSTR IS HIGHER. SO WOULD EXPECT HIGHER MSTR TO ADVECT N AND BE INTERCEPTED BY THE OUTFLOW. HOWEVER...ANOTHER NEGATIVE FACTOR IS THE EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY. THE INHIBITED HEATING MAKES MODELED CAPE QUESTIONABLE. EVEN THE NE LOW-MID LVL FLOW OVER NEB IS NOT BEING CAPTURED BY THE MODELS /THEY CURRENTLY HAVE SE WINDS AND MAINTAIN THEM/. SO FCST VALUES OF DEEP LAYER SHEAR ARE LESS CERTAIN. SO FOR NOW BELIEVE THE HIGHEST FOCUS FOR SVR TSTM POTENTIAL SHOULD BE IN SUNNIEST AREAS /CURRENTLY S AND W OF THE TRI-CITIES/. THE FCST AREA WILL BE IN THE RRQ OF A 60 KT ULJ. THIS SHOULD PROVIDE SUFFICIENT SHEAR FOR THE STRONGEST/TALLEST STORMS AND WOULD ESTIMATE MLCAPE OF 1500-2000 J/KG OF MLCAPE IN THE SUNNIEST AREAS. STORM MOVEMENT FOR INDIVIDUAL/NON-MULTICELL STORMS WILL BE EAST AROUND 10 KTS OVER NRN KS AND AROUND 20 KTS OVER S-CNTRL NEB. UPDATE ISSUED AT 944 AM CDT SAT JUL 20 2013 AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING OUTFLOW BOUNDARY AS EMANATED FROM THESE CLUSTERS AND IS APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD...VERY DRY. WILL HAVE MORE LATER ON THIS. OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/ WX/POPS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 408 AM CDT SAT JUL 20 2013 WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND THUNDERSTORMS THIS EVENING INTO TONIGHT. THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY 281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE. SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE LOWEST ATMOSPHERIC LAYERS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 408 AM CDT SAT JUL 20 2013 MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND TEMPERATURES. MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES NEARLY EVERY DAY. THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS. THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE THROUGH THE AREA. ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR. THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1247 PM CDT SAT JUL 20 2013 THIS AFTN: VFR BUT ISOLATED SHWRS/TSTMS WILL BE NEARBY WITH POCKETS OF MVFR/IFR VSBYS IN +RA. WATCH FOR SHORT-TERM AMENDMENTS AS WE WILL PROVIDE ADDITIONAL DETAILS IF THE TERMINAL IS THREATENED. NE WINDS WILL CONT 10-20 KTS BUT THIS IS DUE TO TSTM OUTFLOW AND NOT PART OF THE BROADER FLOW. SO IT REMAINS UNCERTAIN WHEN THE WIND RETURNS TO E OR SE. TNGT: VFR BUT A 1-2 HR PERIOD OF TSTMS IS POSSIBLE. JUST NOT SURE ON EXACT TIMING OR OCCURRENCE. FUTURE TAFS MAY NEED TO INCLUDE MORE DEFINITIVE TIME FRAME. WIND SHOULD BECOME SE BELOW 10 KTS. THERE IS A SLGT CHANCE OF IFR FOG IS SKIES CLEAR AND WINDS TURN LGT BEHIND TSTMS. SUN THRU 18Z: IFR FOG POSSIBLE TO START...BUT IT/S NOT IN THE TAF UNTIL WE SEE IF TSTMS DEVELOP. WINDS WILL BE LGT AND VARIABLE. CIG CONFIDENCE: MEDIUM VSBY CONFIDENCE: MEDIUM WIND CONFIDENCE: LOW WX CONFIDENCE: LOW && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...WESELY LONG TERM...JCB AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1107 AM CDT SAT JUL 20 2013 .UPDATE... ISSUED AT 1107 AM CDT SAT JUL 20 2013 THE INITIAL COMPOSITE OUTFLOW BOUNDARY CONTS DROPPING STEADILY S AT 22 KTS AND WILL ARRIVE AT THE KS BORDER AROUND 1215 PM. SCT SHWRS WERE DEVELOPING ATOP THIS OUTFLOW AND THIS POTENTIAL IS EXPECTED TO CONT DESPITE THE SEEMINGLY UNFAVORABLE ENVIRONMENT. VIS SATPIX SHOWED ANOTHER OUTFLOW BOUNDARY /FROM THE TSTMS HEADING INTO NE NEB/ THAT WILL MOVE INTO THE NRN FRINGE OF THE FCST AREA SHORTLY /ORD-GREELEY/. THE OAX SOUNDING WAS VERY DRY BELOW 700 MB FROM OVERNGT SUBSIDENCE. HOWEVER...THE OUTFLOW IS CLEARLY ENOUGH TO INITIATE SHWRS WITH EMBEDDED THUNDER. SO THIS REALLY COMPLICATES THE SITUATION TODAY...AND LOWERS CONFIDENCE IN HOW THINGS WILL DEVELOP/EVOLVE. REGIONAL 88D WIND PROFILES SHOW DEEP E-NE FLOW UP TO 9K FT...WHICH WOULD BE ENUF TO INITIATE SHWRS/THUNDER BASED ON THE OAX SOUNDING. GLD AND TOP HAVE MORE SHALLOW S FLOW...WHERE MSTR IS HIGHER. SO WOULD EXPECT HIGHER MSTR TO ADVECT N AND BE INTERCEPTED BY THE OUTFLOW. HOWEVER...ANOTHER NEGATIVE FACTOR IS THE EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY. THE INHIBITED HEATING MAKES MODELED CAPE QUESTIONABLE. EVEN THE NE LOW-MID LVL FLOW OVER NEB IS NOT BEING CAPTURED BY THE MODELS /THEY CURRENTLY HAVE SE WINDS AND MAINTAIN THEM/. SO FCST VALUES OF DEEP LAYER SHEAR ARE LESS CERTAIN. SO FOR NOW BELIEVE THE HIGHEST FOCUS FOR SVR TSTM POTENTIAL SHOULD BE IN SUNNIEST AREAS /CURRENTLY S AND W OF THE TRI-CITIES/. THE FCST AREA WILL BE IN THE RRQ OF A 60 KT ULJ. THIS SHOULD PROVIDE SUFFICIENT SHEAR FOR THE STRONGEST/TALLEST STORMS AND WOULD ESTIMATE MLCAPE OF 1500-2000 J/KG OF MLCAPE IN THE SUNNIEST AREAS. STORM MOVEMENT FOR INDIVIDUAL/NON-MULTICELL STORMS WILL BE EAST AROUND 10 KTS OVER NRN KS AND AROUND 20 KTS OVER S-CNTRL NEB. UPDATE ISSUED AT 944 AM CDT SAT JUL 20 2013 AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING OUTFLOW BOUNDARY AS EMANATED FROM THESE CLUSTERS AND IS APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD...VERY DRY. WILL HAVE MORE LATER ON THIS. OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/ WX/POPS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 408 AM CDT SAT JUL 20 2013 WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND THUNDERSTORMS THIS EVENING INTO TONIGHT. THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY 281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE. SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE LOWEST ATMOSPHERIC LAYERS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 408 AM CDT SAT JUL 20 2013 MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND TEMPERATURES. MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES NEARLY EVERY DAY. THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS. THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE THROUGH THE AREA. ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR. THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 529 AM CDT SAT JUL 20 2013 THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND ANY THUNDERSTORMS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
944 AM CDT SAT JUL 20 2013 .UPDATE... ISSUED AT 944 AM CDT SAT JUL 20 2013 AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING OUTFLOW BOUNDARY AS EMINATED FROM THESE CLUSTERS AND IS APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD. WILL HAVE MORE LATER ON THIS. OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/ WX/POPS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 408 AM CDT SAT JUL 20 2013 WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND THUNDERSTORMS THIS EVENING INTO TONIGHT. THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY 281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE. SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE LOWEST ATMOSPHERIC LAYERS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 408 AM CDT SAT JUL 20 2013 MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND TEMPERATURES. MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES NEARLY EVERY DAY. THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS. THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE THROUGH THE AREA. ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR. THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 529 AM CDT SAT JUL 20 2013 THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND ANY THUNDERSTORMS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
552 AM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 408 AM CDT SAT JUL 20 2013 WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND THUNDERSTORMS THIS EVENING INTO TONIGHT. THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY 281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE. SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE LOWEST ATMOSPHERIC LAYERS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 408 AM CDT SAT JUL 20 2013 MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND TEMPERATURES. MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES NEARLY EVERY DAY. THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS. THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE THROUGH THE AREA. ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR. THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 529 AM CDT SAT JUL 20 2013 THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND ANY THUNDERSTORMS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
414 AM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 408 AM CDT SAT JUL 20 2013 WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND THUNDERSTORMS THIS EVENING INTO TONIGHT. THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY 281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE. SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE LOWEST ATMOSPHERIC LAYERS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 408 AM CDT SAT JUL 20 2013 MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND TEMPERATURES. MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES NEARLY EVERY DAY. THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS. THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE THROUGH THE AREA. ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR. THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1250 AM CDT SAT JUL 20 2013 EXPECT THE WIND WILL REMAIN LIGHT AND OUT OF THE SOUTHEAST THROUGH THE MORNING...BUT SHOULD INCREASE WITH DIURNAL HEATING AND MAY EVEN BE A BIT GUSTY AT TIMES THIS AFTERNOON WITH SOME VEERING TO SOUTH SOUTHEAST. THE WIND WILL AGAIN DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON HEATING AND SHOULD BACK TO A SOUTHEAST WIND. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THEREFORE...HAVE INTRODUCED VICINITY THUNDERSTORMS INTO THE TAF FOR THE EVENING HOURS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
256 AM MDT SAT JUL 20 2013 .DISCUSSION... NOT MUCH CHANGE TO THE GOING FORECAST. AN ACTIVE WEEKEND REMAINS ON TAP WITH HIGH PWATS...SLOW MOVING STORMS AND THUS...INCREASED FLASH FLOOD POTENTIAL. PREVIOUS SHIFT ISSUED A FLASH FLOOD WATCH...AND THIS REMAINS IN GOOD SHAPE. ONE CAVEAT FOR TODAY WILL BE THE AMOUNT OF DEBRIS CLOUDS FROM LAST NIGHTS/ONGOING CONVECTION ACROSS THE AREA. IF THE CLOUD COVER LINGERS...THIS WILL LIMIT INSTABILITY THIS AFTERNOON AND WOULD THEREBY REDUCE RAIN RATES. MODELS MAY BE HINTING AT THIS A BIT...AS INSTABILITY DOES NOT LOOK TO BE AS STRONG AS MODELS WERE SUGGESTING 24 HOURS AGO. NONETHELESS...WITH 140-180 PERCENT OF NORMAL PWATS AND NEAR ZERO STORM MOTION...ANY ONE STORM THAT DEVELOPS COULD POSE FLOODING PROBLEMS. IN ADDITION TO THE HIGH TERRAIN...REMNANT BOUNDARIES WILL BE THE FOCUS FOR TODAYS CONVECTION. SIMILAR STORY IN STORE FOR SUNDAY...THOUGH MORE STABLE AIR STILL LOOKS TO MIGRATE INTO THE EASTERN PLAINS. MORE DRY AIR WILL WORK INTO NORTHERN AND EASTERN NM ON MONDAY AS THE UPPER HIGH BEGINS TO MIGRATE EASTWARD FROM NEVADA. THE MOST UNSTABLE AREA WILL BE ACROSS THE WEST CENTRAL AND SOUTHWEST MOUNTAINS...WHERE HEAVY RAIN POTENTIAL WILL CONTINUE. BY TUESDAY...THE UPPER HIGH WILL BE CENTERED OVER WEST CENTRAL COLORADO. WITH THE HIGH EVEN CLOSER...SUBSIDENCE UNDER THE HIGH WILL LIMIT CONVECTIVE COVERAGE FURTHER...THOUGH THE FAR WEST WILL HAVE THE BEST POTENTIAL FOR CONTINUED STORMS. BY WEDNESDAY...MODELS ARE NOW SUGGESTING THE UPPER HIGH WILL BE CENTERED OVER FAR NE NM. ISOLD/SCT STORMS WILL REMAIN POSSIBLE ACROSS THE FAR WEST...BUT GENERALLY QUIET CONDITIONS ARE EXPECTED ELSEWHERE. BOTH THE ECMWF AND THE GFS TAKE THE UPPER HIGH INTO TEXAS/OKLAHOMA BY THURSDAY NOW...WHICH OPENS THE DOOR FOR THE TRADITIONAL MONSOON PLUME. THAT SAID...BY FRIDAY AFTERNOON...THE HIGH LOOKS TO ELONGATE AND ANY HIGH CENTER BECOMES QUIET MUDDLED. THEN ON SATURDAY...BOTH MODELS ARE SUGGESTING A BACK DOOR COLD FRONT WILL ROLL DOWN THE PLAINS AND INCREASE POTENTIAL FOR STORMS ACROSS THE EAST. STAY TUNED...AS CONFIDENCE REMAINS FAIRLY LOW BEYOND WEDNESDAY. 34 && .FIRE WEATHER... A VERY ACTIVE FRIDAY WILL BE FOLLOWED BY ANOTHER ACTIVE WEATHER DAY TODAY. HOWEVER...ONGOING CONVECTION AND CLOUD COVER MAY BE SLOW TO CLEAR THIS MORNING SO TODAYS ROUND OF SHOWERS AND STORMS COULD GET A LATER START THAN ON FRIDAY. POTENTIAL FOR HEAVY RAIN AND FLASH FLOODING PRETTY HIGH TODAY INTO TONIGHT ESPECIALLY OVER RECENT BURN SCARS AND PLACES THAT HAD HEAVY RAIN AND SOME FLOODING FRIDAY. HIGH PRESSURE TO OUR NORTHWEST WILL GRADUALLY BUILD TOWARD AND OVER NEW MEXICO SUNDAY INTO WEDNESDAY. A SLOW TREND DOWNWARD IN SHOWERS AND STORMS WILL BE THE CASE...WITH THE KEY WORD BEING SLOW...AS LOW LEVELS TO REMAIN MOIST WHILE MID AND UPPER LEVELS GRADUALLY DRY OUT. MODELS TAKE CENTER OF HIGH PRESSURE A LITTLE EAST OF NEW MEXICO FOR THE END OF NEXT WEEK...WHILE AN EASTERLY WAVE DRIFTING NORTHEAST FROM MEXICO MAY BEGIN TO IMPACT THE SOUTHWEST PORTIONS OF THE STATE. THIS WOULD ALLOW FOR A MORE CLASSIC MONSOONAL SURGE OF MOISTURE FOR THE WEST THURSDAY AND FRIDAY. MODELS DIVERGE BY NEXT WEEKEND WITH THE GFS KEEPING THE HIGH CENTER TO OUR EAST WHILE THE EUROPEAN BUILDS THE HIGH BACK OVER AND A LITTLE WEST OF THE STATE. BOTH MODELS THOUGH BRING COPIOUS AMOUNTS OF RAIN FOR NEXT WEEKEND AS THE EUROPEAN HAS A BACK DOOR FRONT BLASTING INTO NEW MEXICO WHILE THE GFS HAS THE EARLIER MENTIONED EASTERLY WAVE COMING UP THROUGH AZ AND WESTERN NM...WITH A WEAKER PUSH FROM THE BACK DOOR COLD FRONT. HIGH TEMPERATURES WILL GRADUALLY WARM THROUGH MIDWEEK WHILE MINIMUM RH VALUES LOWER. NIGHTTIME RECOVERIES WILL REMAIN MOSTLY GOOD TO EXCELLENT ASIDE FROM FAIR MOST NIGHTS IN THE NORTHWEST. VENTILATION WILL BE FAIR OR BETTER FOR THE MOST PART EXCEPT FOR SOME POOR RATES IN THE NORTHWEST TODAY...RIO GRANDE VALLEY SUNDAY AND WEST TUESDAY. CHJ && .AVIATION... 06Z TAF CYCLE A BROAD AREA OF SLOW MOVING SHOWERS AND THUNDERSTORMS OVER NE NM IS EXPECTED TO DRIFT SLOWLY S AND SSW FOR THE REMAINDER OF THE NIGHT. MEANWHILE...MODELS DEPICT CONVECTION IN THE W CENTRAL AND SW MTS GRADUALLY DIMINISHING OR EXITING WESTWARD. HOWEVER...THESE CELLS LOOK STRONG ENOUGH TO LAST THROUGH AT LEAST 09Z. THE HRRR MODEL...WHICH HAS BEEN DOING PRETTY GOOD LATELY...ALSO DEPICTS A SMALL CLUSTER OF CELLS SHIFTING FROM NEAR KSAF SWWD THROUGH THE KABQ/KAEG AREA LATE TONIGHT. ANOTHER ROUND OF SCT-NMRS STORMS IS EXPECTED SATURDAY AFTN AND EVENING...WITH THE POTENTIAL FOR MORE HEAVY RAIN...MT OBSCURATIONS AND HAIL. WITH THE 500 MB HIGH PRESSURE CENTER OVER NV...THE CONVECTION SHOULD CONTINUE TO TRACK TOWARD THE S...SW AND W ACROSS NM. 44 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 91 65 93 66 / 30 30 20 30 DULCE........................... 84 52 87 54 / 50 50 40 40 CUBA............................ 83 54 86 54 / 50 50 50 50 GALLUP.......................... 83 59 85 59 / 50 50 40 40 EL MORRO........................ 79 53 79 53 / 60 50 50 50 GRANTS.......................... 82 58 83 58 / 40 50 40 40 QUEMADO......................... 81 56 81 57 / 60 60 50 50 GLENWOOD........................ 82 57 83 58 / 40 40 50 40 CHAMA........................... 79 48 80 50 / 70 60 50 40 LOS ALAMOS...................... 79 60 82 62 / 50 50 50 40 PECOS........................... 73 58 77 60 / 50 60 50 40 CERRO/QUESTA.................... 78 54 80 55 / 60 50 40 40 RED RIVER....................... 71 44 75 44 / 70 60 50 40 ANGEL FIRE...................... 73 43 77 43 / 70 60 50 40 TAOS............................ 81 53 86 54 / 50 50 40 30 MORA............................ 72 54 78 55 / 60 60 50 40 ESPANOLA........................ 83 59 86 60 / 40 40 40 30 SANTA FE........................ 79 59 83 61 / 50 60 50 40 SANTA FE AIRPORT................ 82 60 86 62 / 50 50 40 30 ALBUQUERQUE FOOTHILLS........... 84 65 88 68 / 60 60 40 40 ALBUQUERQUE HEIGHTS............. 85 67 89 70 / 50 50 30 30 ALBUQUERQUE VALLEY.............. 86 65 90 68 / 40 40 30 30 ALBUQUERQUE WEST MESA........... 86 65 90 67 / 40 40 30 40 LOS LUNAS....................... 88 64 89 67 / 40 40 20 30 RIO RANCHO...................... 87 65 91 67 / 40 40 30 30 SOCORRO......................... 92 65 93 66 / 30 30 20 30 SANDIA PARK/CEDAR CREST......... 83 59 86 61 / 60 60 50 40 TIJERAS......................... 81 60 84 63 / 50 60 50 40 MORIARTY/ESTANCIA............... 80 58 83 59 / 50 50 40 40 CLINES CORNERS.................. 79 58 82 60 / 40 50 40 40 GRAN QUIVIRA.................... 80 58 82 60 / 40 40 40 30 CARRIZOZO....................... 82 61 84 64 / 30 30 30 20 RUIDOSO......................... 73 53 74 56 / 50 30 40 30 CAPULIN......................... 79 56 84 58 / 50 50 20 20 RATON........................... 83 57 89 58 / 50 40 30 30 SPRINGER........................ 83 58 88 59 / 40 50 30 20 LAS VEGAS....................... 79 57 83 57 / 50 50 30 30 CLAYTON......................... 87 65 93 66 / 30 30 10 10 ROY............................. 82 63 86 64 / 40 30 10 20 CONCHAS......................... 88 67 92 69 / 20 20 10 10 SANTA ROSA...................... 87 65 91 68 / 20 20 10 10 TUCUMCARI....................... 92 69 95 71 / 20 20 10 10 CLOVIS.......................... 87 64 89 65 / 10 10 5 10 PORTALES........................ 88 65 89 65 / 10 10 5 5 FORT SUMNER..................... 88 67 90 68 / 10 10 10 10 ROSWELL......................... 90 67 92 69 / 10 10 5 10 PICACHO......................... 84 60 86 63 / 20 20 10 10 ELK............................. 77 57 79 59 / 40 30 20 20 && .ABQ WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES... NMZ501>529. && $$ 34
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1151 PM MDT FRI JUL 19 2013 .AVIATION... 06Z TAF CYCLE A BROAD AREA OF SLOW MOVING SHOWERS AND THUNDERSTORMS OVER NE NM IS EXPECTED TO DRIFT SLOWLY S AND SSW FOR THE REMAINDER OF THE NIGHT. MEANWHILE...MODELS DEPICT CONVECTION IN THE W CENTRAL AND SW MTS GRADUALLY DIMINISHING OR EXITING WESTWARD. HOWEVER...THESE CELLS LOOK STRONG ENOUGH TO LAST THROUGH AT LEAST 09Z. THE HRRR MODEL...WHICH HAS BEEN DOING PRETTY GOOD LATELY...ALSO DEPICTS A SMALL CLUSTER OF CELLS SHIFTING FROM NEAR KSAF SWWD THROUGH THE KABQ/KAEG AREA LATE TONIGHT. ANOTHER ROUND OF SCT-NMRS STORMS IS EXPECTED SATURDAY AFTN AND EVENING...WITH THE POTENTIAL FOR MORE HEAVY RAIN...MT OBSCURATIONS AND HAIL. WITH THE 500 MB HIGH PRESSURE CENTER OVER NV...THE CONVECTION SHOULD CONTINUE TO TRACK TOWARD THE S...SW AND W ACROSS NM. 44 && .PREV DISCUSSION...725 PM MDT FRI JUL 19 2013... BASED ON RADAR TRENDS TODAY AND EXPECTED HEAVY/TORRENTIAL RAIN POTENTIAL THROUGH THE WEEKEND...DECIDED TO HOIST A FLASH FLOOD WATCH FOR CENTRAL AND WESTERN NM. PWAT VALUES WILL COME UP EVEN A LITTLE HIGHER FOR THE REGION AND STEERING FLOW WILL CONTINUE TO WEAKEN. CONSIDERING IMPACTS FROM STORMS TODAY WE EXPECT VERY SIMILAR CONDITIONS THROUGH AT LEAST SUNDAY EVENING. FFA ALREADY ON THE STREET AND PRODUCT UPDATES FOLLOWING SHORTLY. GUYER .PREV DISCUSSION...258 PM MDT FRI JUL 19 2013... ROBUST ROUND OF THUNDERSTORMS ON THE UPTREND AS OF 3PM...MOVING WSW FROM THE NORTHERN MOUNTAINS AND NE HIGHLANDS/PLAINS. A REPORT OF 1.54 INCHES IN LESS THAN ONE HOUR CAME IN FROM NEAR 10 MILES SOUTH OF SANTA FE...SO THESE STORMS ARE CERTAINLY CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL. THE 12Z KABQ PWAT WAS 1.27 INCHES...WHICH IS 147 PERCENT OF NORMAL AND CLOSE TO +2 STANDARD DEVIATIONS ABOVE NORMAL. IN ADDITION TO THE JUICY ATMOSPHERE OVERHEAD...STORM MOTIONS IS 10 MPH OR LESS WHICH ADDS TO THE LOCALLY HEAVY RAINFALL THREAT. STORMS APPROACHING THE ABQ METRO FROM THE NE WILL CERTAINLY HAVE A PRIMED AIRMASS TO WORK OVER... WITH THE 20Z LAPS ANALYSIS SHOWING SURFACE BASED CAPES AROUND 2000 J/KG AND LIFTED INDICES BETWEEN -4 AND -5C. MAIN IMPACT PERIOD FOR THE ABQ METRO WILL BE FROM 330 TO 530PM MDT. SHOWERS AND THUNDERSTORMS WILL PERSIST INTO THE EVENING HOURS...BUT SHOULD DIMINISH SHORTLY AFTER MIDNIGHT WITH NO SUNRISE SURPRISES SATURDAY MORNING. SATURDAY WILL BE SIMILAR OVERALL WITH WELL ABOVE NORMAL PWATS... BUT SLOWER STORM MOTION TO THE WEST OR SOUTHWEST. LOCALLY HEAVY RAINFALL AMOUNTS OF 1 TO 2 INCHES WILL BE POSSIBLE AGAIN... ESPECIALLY OVER THE MOUNTAIN ZONES. SUNDAY WILL BE A TAD WARMER/DRIER OVERALL AS PRESSURE HEIGHTS INCREASE WITH THE UPPER HIGH OVER NEVADA RIDGING INTO COLORADO AND NORTHERN NM. SUNDAY`S CROP OF THUNDERSTORMS WILL LIKELY HUG THE TERRAIN A BIT MORE AS WELL WITH EVEN LIGHTER STEERING FLOW. THE FORECAST TRENDS AND CHALLENGES BEYOND MONDAY HAVE NOT CHANGED THIS FORECAST CYCLE. A GRADUAL TEMPERATURE UPTREND AND CONVECTIVE DOWNTREND IS FORECAST NEXT WEEK AS THE UPPER HIGH MOVES SLOWLY ESE ACROSS NM AND INTO TEXAS. SOME DIFFERENCES ARE STILL SHOWING UP IN THE PLACEMENT OF THE UPPER HIGH CENTROID BY FRIDAY OF NEXT WEEK...WITH THE ECMWF STILL SHOWING IT EAST OF NM. SO AT SOME POINT LATE NEXT WEEK...OR POSSIBLY DELAYED UNTIL THE WEEKEND...TEMPERATURES WILL TREND BACK DOWN AND RAIN CHANCES WILL TREND BACK UP AS A MORE TRADITIONAL MONSOON PATTERN SETS UP. THAT SAID...LOW FORECAST CONFIDENCE BEYOND WEDNESDAY AT THIS TIME. 11 .FIRE WEATHER... ISOLATED SHOWERS AND THUNDERSTORMS EXPECTED TO CONTINUE TONIGHT WITH A JUICY AIRMASS IN PLACE AND SOME WEAK ATMOSPHERIC LIFT REMAINING OVER THE AREA. BACK DOOR COLD FRONT OVER NE PLAINS AND HIGHLANDS WILL KEEP A FEW STRONG STORMS GOING THERE UNTIL AROUND MIDNIGHT ALONG WITH ISOLATED SHOWERS THROUGH THE EARLY MORNING. PARTIAL CLEARING MAY INHIBIT OVERNIGHT RELATIVE HUMIDITY RECOVERIES SLIGHTLY BUT STILL EXPECTING VERY GOOD TO EXCELLENT RECOVERY VALUES MOST PLACES BY EARLY MORNING SATURDAY WITH WIDESPREAD WETTING RAINS. ANOTHER ACTIVE TO VERY ACTIVE DAY IN STORE SATURDAY WITH THE UPPER LEVEL WEATHER PATTERN CHANGING LITTLE AND PLENTY OF MOISTURE IN PLACE...POSSIBLY INCREASING SOMEWHAT MORE WITH A WEAK TO MODERATE SOUTHERLY SURFACE FLOW DEVELOPING. PREVIOUS WEATHER PREDICTION MODEL INDICATIONS WERE THAT A DOWNTREND IN CONVECTION WOULD BEGIN SUNDAY AS THE DEEPER MOISTURE HEADED WESTWARD INTO ARIZONA. LATEST DATA...HOWEVER...SUGGESTS THAT THIS MAY NOT BE THE CASE. WHILE SOME DRIER AIR ALOFT BEGINS TO FILTER IN FROM THE NORTHEAST...PLENTY OF LOW AND MID LEVEL MOISTURE EXPECTED TO CONTINUE TO PUSH UP FROM SOUTH FROM DECAYING CONVECTIVE COMPLEXES OVER NORTHERN OLD MEXICO SUNDAY MORNING. ANOTHER ACTIVE DAY IN STORE MONDAY AS THE UPPER HIGH MOVES LITTLE AND PLENTY OF LOW LEVEL MOISTURE LEFT IN PLACE TO RECYCLE. AT THIS POINT IN TIME...TUESDAY APPEARS TO BE THE FIRST OF SEVERAL DOWN DAYS AS VERY DRY AIR ALOFT BEGINS TO MOVE IN FROM THE EAST/SE. GENERAL TREND OF THE MEDIUM RANGE MODELS IS TO SHIFT THE FOUR CORNERS HIGH SLOWLY EASTWARD WEDNESDAY NIGHT INTO THURSDAY...ALLOWING FOR A CLASSIC SOUTHERLY MONSOONAL FLOW. BOTH ECMWF AND GFS INDICATING THAT AN EASTERLY WAVE MAY ALSO GET INTO THE MIX...MOVING UP INTO SW AZ THURSDAY NIGHT AND FRIDAY...ENHANCING THE DEEP SOUTHERLY MONSOONAL FLOW OVER NM TOWARD THE END OF THE WORK WEEK. 33 && .ABQ WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES... NMZ501>529. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1032 PM EDT SUN JUL 21 2013 .SYNOPSIS... FAIRLY SEASONABLE TEMPERATURES AND A NORMAL SCATTERING OF AFTERNOON STORMS ARE EXPECTED THE NEXT SEVERAL DAYS...COMPLIMENTS OF BERMUDA HIGH PRESSURE. A COLD FRONT DROPPING CLOSE TO THE REGION ON THURSDAY WILL STALL AND KEEP THE WEATHER A BIT MORE UNSETTLED. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1030 PM SUNDAY...WATER VAPOR IMAGERY SHOWS AN ANTICYCLONIC (CLOCKWISE) SPIN OVER THE EASTERN CAROLINAS. MODELS ARE STRUGGLING TO CONSISTENTLY LOCATE REGIONS OF CYCLONIC CURVATURE THAT MAY BE HELPING SUSTAIN CLUSTERS OF SHOWERS AND T-STORMS. AGAIN REFERENCING WATER VAPOR IMAGERY IT APPEARS ONE UPPER DISTURBANCE LIES ACROSS CENTRAL NORTH CAROLINA INTO WEST-CENTRAL SOUTH CAROLINA...WHILE A SECOND MORE QUIESCENT DISTURBANCE LIES OFF THE GEORGIA AND SOUTHERN SOUTH CAROLINA COAST. THE AIRMASS REMAINS SEASONABLY WARM...BUT MOISTURE CONTENT AS MEASURED BY PRECIPITABLE WATER IS VERY HIGH: 2.2 INCHES. LAPSE RATES ARE NOT PARTICULARLY STEEP BUT ARE JUST LARGE ENOUGH THROUGH THE 900-600 MB LAYER TO PROMOTE GOOD UPDRAFT ACCELERATION. IR SATELLITE SHOWS CLOUD TOP TEMPERATURES MAINTAINING LARGE AREAS COLDER THAN -60C. BASED ON RECENT TRENDS AND THE LAST SEVERAL HRRR RUNS (WHICH HAVEN`T BEEN BAD THIS EVENING) THE CONVECTION ACROSS THE SC PEE DEE REGION SHOULD LARGELY DISSIPATE WITHIN THE NEXT 2-3 HOURS WHILE NEW CONVECTION DEVELOPS CLOSER TO THE COAST...ESPECIALLY THE NC COAST. AFTER 2 AM MOST OF THE CONVECTION SHOULD EXIT THE LANDMASS AND MOVE EASTWARD INTO THE OCEAN. HIGH-REFLECTIVITY (>50DBZ) CORES HAVE SO FAR REMAINED VERY LOW IN THE STORMS...BARELY ABOVE THE FREEZING LEVEL. THIS IS CORRELATED WITH EFFICIENT HEAVY RAIN PRODUCTION BUT NOT WITH SEVERE WEATHER. SINCE CELL MOVEMENT REMAINS SLOW FROM THE WEST FLOODING WILL BE THE PRIMARY THREAT TO WATCH FOR THE NEXT SEVERAL HOURS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...COPIOUS MOISTURE REMAINS IN PLACE ON MONDAY WITH PRECIPITABLE WATER STILL ABOVE 2 INCHES. WHILE WIDESPREAD CLOUD COVER INHIBITED INSOLATION AND THUS CONVECTIVE COVERAGE TODAY THIS APPEARS A LITTLE LESS LIKELY MONDAY.FCST SOUNDINGS LESS INDICATIVE OF WIDESPREAD SC EARLY IN THE DAY SO EXPECT BETTER HEATING AND THUS COVERAGE OF STORMS. ITS HARD TO PIN DOWN ANY FAVORED AREAS FOR HIGHER POPS...ABUT A LATE DAY UPPER VORT AND SFC TROUGH MAY FOCUS ACTIVITY OVER WESTERN ZONES EVEN AS A LARGER SCALE DIURNAL WANING IS UNDERWAY. A STRONGER VORT WILL SCOOT BY TO OUR NORTH ON TUESDAY...PERHAPS AROUND MIDDAY. IN ITS WAKE WILL BE A SUPPRESSING EFFECT ON CONVECTION AND SOME 20-30 POPS SEEM ALL THAT IS WARRANTED. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...PATTERN ALOFT REMAINS AMPLIFIED THROUGH THE PERIOD WITH 5H TROUGHING OVER THE EAST COAST AND RIDGING OUT WEST. THIS MAINTAINS ACTIVE WEATHER ACROSS THE SOUTHEAST WITH PIEDMONT TROUGH AND SEA BREEZE BEING THE FOCUS ON WED. FROM THU ON WEAK COLD FRONT MOVES INTO THE REGION BUT STALLS WITH FLOW ALOFT BECOMING PARALLEL TO THE SURFACE BOUNDARY. HAVE A HARD TIME BELIEVING THE FRONT WILL MAKE IT TO THE COAST FOR ANY LENGTH OF TIME WITH THE 5H TROUGH AXIS REMAINING WEST OF THE AREA. WEAK WAVES DEVELOPING ON THE FRONT WILL BRIEFLY PUSH THE BOUNDARY TO THE COAST BEFORE ALLOWING IT TO RETURN INLAND. IN ADDITION TO NUDGING THE FRONT EAST OR WEST THESE WAVES SHOULD HELP GENERATE AND ENHANCE CONVECTION. TIMING THE FEATURES AT THIS POINT IS DIFFICULT AT BEST SO WILL MAINTAIN CHANCE POP THROUGH THE FORECAST PERIOD. FRONT WILL SLOWLY DISSIPATE DURING THE SECOND HALF OF THE PERIOD...EVENTUALLY MERGING WITH THE PIEDMONT TROUGH. NEXT WEEKEND A SHORTWAVE MOVING INTO THE MS VALLY INDUCES A SURFACE LOW WHICH THEN LIFTS NORTHEAST THROUGH THE OH VALLEY. COLD FRONT ASSOCIATED WITH THE LOW MOVES INTO THE CAROLINAS LATE IN THE PERIOD. STRONGER 5H TROUGH SUGGESTS THIS FRONT MAY HAVE A BETTER CHANCE OF REACHING OR MOVING OFF THE COAST. AT THE VERY LEAST IT WILL RESULT IN AN INCREASE IN PRECIP CHANCES FOR THE WEEKEND...ESPECIALLY SUN. DAILY CONVECTION AND CLOUD COVER WILL KEEP HIGHS NEAR TO SLIGHTLY BELOW CLIMO WHILE SOUTHERLY FLOW...MOISTURE AND LEFT OVER DEBRIS CLOUD KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 00Z...DUE TO SCATTERED NATURE OF SHOWER ACTIVITY WILL ELECT TO INDICATE VCSH IN TAFS THIS EVENING AT ALL TERMINALS ALTHOUGH THE CHANCE OF ANY TERMINAL BEING AFFECTED IS RATHER SMALL. SHOWERS WILL GRADUALLY DISSIPATE BY MIDNIGHT LOCAL OVER LAND THEN BEGIN TO DEVELOP IN THE COASTAL WATERS. TEMPO MVFR CIGS WILL BE POSSIBLE AT THE COASTAL TERMINALS TERMINALS THIS EVENING. MVFR CIGS WILL BECOME MORE LIKELY BY MIDNIGHT LOCAL AT THE COASTAL TERMINALS. VSBYS SHOULD DROP TO MVFR IN BR AT KFLO/KLBT BY MIDNIGHT LOCAL WITH SCATTERED IFR STRATUS. AFTER MIDNIGHT THERE IS INCREASING CONFIDENCE OF IFR CIGS AT ALL TERMINALS. ANY IFR CIGS SHOULD RISE TO MVFR BY 14Z WITH VFR DEVELOPING LATE MORNING INTO EARLY AFTERNOON. SHOULD BE A GOOD CHANCE OF VCSH AT THE COASTAL TERMINALS BY NOON LOCAL WITH VCTS DEVELOPING AT KFLO/KLBT WITH THE APPROACH OF AN UPPER IMPULSE. EXTENDED OUTLOOK...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THURSDAY...WITH BRIEF LOCALIZED PERIODS OF MVFR/IFR POSSIBLE. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM/THROUGH TONIGHT/... AS OF 1030 PM SUNDAY...ASIDE FROM BUMPING UP SEAS BY A FOOT IN SPOTS BASED ON LATEST OBSERVATIONS...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. IF CONDITIONS WERE ANY WORSE WE WOULD BE FORCED TO APPEND AN EXERCISE CAUTION HEADLINE TO THE FORECAST...PARTICULARLY ALONG THE BRUNSWICK COUNTY COAST. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... WINDS FINALLY SURGED UP IN THE LAST FEW HOURS BUT ARE STILL WELL BELOW ADVISORY THRESHOLDS. RECENT GUSTS INCLUDE 21 KNOTS AT THE FRYING PAN SHOALS BUOY...NORTH MYRTLE BEACH...AND OAK ISLAND...20 KNOTS ON BALD HEAD ISLAND...AND 19 KNOTS IN GEORGETOWN. THESE STRONGER SOUTHWEST WINDS MAY CONTINUE THROUGH 11 PM OR MIDNIGHT BEFORE A LANDBREEZE PRODUCES MUCH LIGHTER WEST-SOUTHWEST WINDS NEAR THE BEACHES...SPREADING OUT AWAY FROM THE COAST OVERNIGHT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...WEAK WAVE OF LOW PRESSURE NEAR DELMARVA WILL VEER LOCAL FLOW SLIGHTLY TO A MORE WESTERLY DIRECTION THAN THE TYPICAL SW FOR PART OF MONDAY. LATER IN THE DAY SW FLOW GETS ESTABLISHED WITH ABOUT A 5KT INC IN SPEED. THIS TREND WILL CONTINUE INTO MONDAY NIGHT BUT NOT TO WHERE CAUTIONARY HEADLINES WARRANTED AS SEAS NOT EXPECTED TO BUILD QUITE ENOUGH WITHIN 20NM BORDER. PIEDMONT TROUGHINESS DEVELOPS LATER FRIDAY AND SHOULD MAINTAIN SLIGHTLY HIGHER WIND SPEEDS THAN WHAT SEASONABLE...15 TO 20KT MOST ZONES. A LITTLE LIGHTER FLOW OVER SRN LEGS WHICH SHOULD PREVENT 5 FT SEAS OFF GTOWN. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD WITH WATERS IN BETWEEN BERMUDA HIGH AND PIEDMONT TROUGH/WEAK COLD FRONT. WINDS AND SEAS WILL BE HIGHEST EARLY IN THE PERIOD. GRADIENT RELAXES AS FRONT/TROUGH MOVE CLOSER TO THE COAST AND WEAK SURFACE WAVES DEVELOP ON THE BOUNDARY. SPEEDS WILL BE 10 TO 15 KT WED THEN DECREASE TO AROUND 10 KT FOR THU AND FRI. SEAS WILL FALL FROM 3 TO 4 FT ON WED TO AROUND 2 FT FRI. && .TIDES/COASTAL FLOODING... AS OF 1030 PM SUNDAY...THE CAPE FEAR RIVER CRESTED AT 6.23 FEET MLLW AT DOWNTOWN WILMINGTON THIS EVENING. THIS IS SIMILAR TO LAST NIGHT...AND IS THE RESULT OF THE ASTRONOMICAL HIGH TIDE ASSOCIATED WITH THIS MONTH`S FULL MOON...PLUS A LARGE AMOUNT OF WATER DRAINING DOWN THE CAPE FEAR RIVER SYSTEM FROM EXCESSIVE RAINS OVER THE PAST FEW WEEKS UPSTREAM. UNFORTUNATELY IT LOOKS LIKE AT LEAST THE NEXT TWO EVENING HIGH TIDES ALONG THE CAPE FEAR WILL PROBABLY INDUCE MORE MINOR FLOODING. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...COASTAL FLOOD ADVISORY FROM 8 PM TO 11 PM EDT THIS EVENING FOR NCZ107. MARINE...NONE. && $$ SYNOPSIS...MBB NEAR TERM...TRA SHORT TERM...MBB LONG TERM...III AVIATION...MRR COASTAL FLOODING...TRA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
840 PM EDT SUN JUL 21 2013 .SYNOPSIS... A SURFACE TROUGH WILL PERSIST OVER THE REGION...IN A MOIST AIR MASS...AT LEAST THROUGH THE MIDDLE OF THE WEEK...AS A TROUGH IN THE UPPER LEVELS OF THE ATMOSPHERE MOVES INTO THE MID ATLANTIC AND THE CAROLINAS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 310 PM SUNDAY... THE LATEST SURFACE ANALYSIS CONTINUED TO SHOW THE SURFACE TROUGH OVER THE NORTHWEST PIEDMONT TOWARD THE UPSTATE OF SOUTH CAROLINA... AND ALONG THIS TROUGH WHERE BETTER SURFACE CONVERGENCE EXISTED...SCATTERED SHOWERS AND THUNDERSTORMS WERE OCCURRING OR DEVELOPING. DOWNDRAFT CAPE AND LOW-LEVEL SHEAR REMAINED LIMITED... BUT THE LATEST SPC MESOANALYSIS SHOWED MIXED-LAYER CAPE AROUND 2000J/KG NEAR THE SURFACE TROUGH. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD CONTINUE TO MOVE INTO THE WESTERN PIEDMONT DURING THE LATE AFTERNOON...AND THE HRRR WRF HAS BEEN CONSISTENT SHOWING SCATTERED SHOWERS AND THUNDERSTORMS SPREADING EAST TO ABOUT U.S. 1 THROUGH 01Z BEFORE GENERALLY DIMINISHING. THROUGHOUT THE DAY...THE RUC HAS BEEN PERSISTENT MAINTAINING SOME CHANCES FOR SHOWERS ACROSS THE SANDHILLS AND CENTRAL AND SOUTHERN COASTAL PLAIN...WHERE THE GFS HAS SLIGHTLY GREATER 850MB LIFT OVERNIGHT AND WHERE THAT MODEL ALSO FORECASTS A RELATIVE MAXIMUM OF POTENTIAL VORTICITY MOVING ACROSS THE AREA. GIVEN THIS...IT IS POSSIBLE THAT SOME OF THE SHOWERS OVER WESTERN NORTH CAROLINA OR THE UPSTATE OF SOUTH CAROLINA WILL PERSIST AS THEY DRIFT EAST NEAR AND JUST NORTH OF THE SOUTH CAROLINA BORDER OVERNIGHT. WILL KEEP A SLIGHT CHANCE OF SHOWERS FOR THE OVERNIGHT HOURS AFTER MIDNIGHT MAINLY EAST OF A LINE FROM ABOUT KRWI TO KFAY. UNDER A PARTLY-TO-MOSTLY CLOUDY SKY...WITH AREAS OF CLOUDS COURTESY OF DEEP CONVECTION AND THEN SOME HIGH CLOUDS MOVING IN FROM THE WEST LATE...OVERNIGHT LOWS WILL AGAIN BE 70 TO 75 DEGREES. THE SREF SHOWS THE POTENTIAL FOR LOW CLOUDS TO BE LESS THAN THE LAST COUPLE OF MORNINGS...HOWEVER...SOME OF THE GUIDANCE MAINTAINS THE CHANCES FOR LOW CLOUDS PARTICULARLY TOWARD KRDU...KFAY...AND KRWI...LESS TOWARD THE TRIAD. IF LOW CLOUDS INDEED OCCUR...IT IS CURRENTLY THOUGHT THEY SHOULD BE LESS WIDESPREAD THAN WHAT HAS OCCURRED THIS WEEKEND. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... AS OF 310 PM SUNDAY... MONDAY AND MONDAY NIGHT... BOTH THE NAM AND THE GFS GRADUALLY MOVE THE WEAK UPPER LOW OVER THE SOUTHERN MISSISSIPPI RIVER SLOWLY NORTHEAST...AND INDEED THE LATEST WATER VAPOR IMAGERY SHOWS THIS WEAK LOW MOVING MORE INTO MISSISSIPPI. BY THE TIME THE UPPER LOW GETS TO CENTRAL NORTH CAROLINA...IT IS FORECAST TO WEAKEN FURTHER...AND FORECAST PARAMETERS OF INSTABILITY...SHEAR...AND MOISTURE ARE SIMILAR TO WHAT HAS RECENTLY OCCURRED. 850MB THETA-E IS PERSISTENT AROUND 340K AS WELL...CURRENTLY SUGGESTIVE OF LITTLE OVERALL CHANGE IN ANTICIPATED CONDITIONS. WITH THE WEAK UPPER LOW THE GFS DOES FORECAST A VERY MODEST 35KT JETLET INTO CENTRAL NORTH CAROLINA AT 300MB MONDAY AFTERNOON...BUT WITH MIXED-LAYER CAPE FROM ABOUT 1000J/KG TO 2000J/KG AND DOWNDRAFT CAPE REMAINING 500J/KG OR LESS...THINK CONDITIONS WILL BE SIMILAR TO THE LAST COUPLE OF DAYS...MOSTLY SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS...HIGHER CHANCES RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA TOWARD THE WESTERN PIEDMONT AS THE WEAK LOW OR ITS REMNANTS APPROACHES...AND A PARTLY SUNNY DAY ON AVERAGE WITH HIGHS AROUND 90. MONDAY NIGHT...BOTH THE NAM AND THE GFS FORECAST ALMOST A WEAK PSEUDO FRONT OR STRONG TROUGH MOVING INTO THE WESTERN PART OF CENTRAL NORTH CAROLINA WITH DIMINISHING PRECIPITABLE WATER VALUES BEHIND IT TO NEAR 1.5 INCHES LATE TOWARD THE YADKIN RIVER AND DEW POINTS FALLING INTO THE UPPER 60S. BUFR SOUNDINGS BECOME SOMEWHAT MORE STABLE OVERNIGHT IN CENTRAL NORTH CAROLINA...AND QPF IS CERTAINLY LIMITED...BUT WITH THE APPROACH OF THIS TROUGH WILL MAINTAIN A SLIGHT CHANCE OF A SHOWER THROUGH THE OVERNIGHT HOURS. OVERNIGHT LOWS ABOUT A DEGREE OR TWO COOLER THAN WHAT SHOULD OCCUR TONIGHT...BUT STILL 70 TO 75...MAYBE AN UPPER 60S LOW OR TWO TOWARD THE FAR WESTERN PIEDMONT. -DJF TUESDAY THROUGH WEDNESDAY NIGHT... HEIGHTS WILL CONTINUE TO SLOWLY FALL ALOFT TUESDAY AND WEDNESDAY AS A BROAD TROUGH BECOMES ESTABLISHED OVER THE EASTERN US. MEANWHILE...A COLD FRONT TO OUR NORTH WILL SLOWLY SINK SOUTHEAST AND EVENTUALLY MERGE WITH RELATIVELY STRONG LARGE SCALE LOW LEVEL TROUGH EAST OF THE MOUNTAINS. ENERGY CURRENTLY MOVING OUT OF MONTANA/WYOMING IS FORECAST MOVE THROUGH THE BASE OF THE UPPER TROUGH TUESDAY...FOLLOWED BY ANOTHER SHORTWAVE ON WEDNESDAY. HOWEVER...THE TIMING AND STRENGTH OF THESE WEAK WAVES AND OTHER DISTURBANCES WITHIN THE FLOW ARE STILL NEBULOUS. FORECAST SOUNDINGS DO INDICATE A BIT MORE WESTERLY FLOW ON TUESDAY...WITH PW TEMPORARILY DROPPING TO 1.5" OR LESS OVER THE WESTERN CWA AND THE INTRUSION OF DRIER MID LEVEL AIR. HOWEVER...WITH THE MEAN TROUGH AXIS STILL WEST OF OUR AREA... PROFILES MOISTEN BACK UP ON WEDNESDAY WITH MORE ENERGY APPROACHING FROM THE WEST. UNDER CYCLONIC FLOW ALOFT AND MODERATE INSTABILITY...WE SHOULD SEE SCATTERED STORMS BOTH DAYS BUT BETTER COVERAGE OVER THE EAST IN THE VICINITY OF BETTER LOW LEVEL CONVERGENCE AND DEEP MOISTURE. HIGHS 88-92. LOWS IN UPPER 60S AND LOWER 70S. -BLS && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 PM SUNDAY... THE LAST IN A SERIES OF UPPER DISTURBANCES IS FORECAST TO PASS THROUGH THE UPPER TROUGH ON THURSDAY...WITH MODELS HAVING TRENDED DRIER FRIDAY AND SATURDAY AS THE REMNANT FRONTAL ZONE OVER THE EAST COAST STATES SLIDES LITTLE FURTHER EAST TOWARD THE COAST. THERE SHOULD BE LESS COVERAGE IF STORMS THURSDAY AS THE MID LEVELS BEGIN TO DRY OUT...BUT THE PASSAGE OF THE MEAN TROUGH AXIS AND SLIGHTLY STRONGER MID-LEVEL FLOW MAY STILL SUPPORT SOME STRONG TO SEVERE STORMS. LOWER DEWPOINTS BEHIND THE FRONT/TROUGH SHOULD LIMIT CONVECTION FRIDAY AND SATURDAY...PARTICULARLY IN THE WEST. THICKNESSES FALL AS WELL...WITH HIGHS LIKELY TO BE MORE IN THE MID AND UPPER 80S. THE BROAD EASTERN US TROUGH IS EXPECTED TO RELOAD BY THE END OF THE WEEKEND AS ENERGY CONTINUES TO ROTATE AROUND AN UPPER LOW NORTH OF THE HUDSON BAY. BOTH THE ECMWF AND GFS SHOW A MODEST LOW PRESSURE SYSTEM MOVING OFF THE FRONT RANGE SATURDAY AND MOVING TOWARD THE MID-ATLANTIC STATES BY SUNDAY/MONDAY...THOUGH WPC/S EXTENDED DISCUSSION RAISES SOME DOUBT IN THE STRENGTH OF SUCH A FEATURE. NONETHELESS...THERE IS ENOUGH AGREEMENT IN THE MODELS TO HAVE MEDIUM CONFIDENCE IN TEMPS SLIGHTLY BELOW NORMAL OVER THE WEEKEND AND ANOTHER CHANCE OF STORMS BY THE END OF THE WEEKEND. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 845 PM SUNDAY... THERE IS A CHANCE OF THUNDERSTORMS MOSTLY EAST OF THE KINT/KGSO TERMINALS THIS EVENING. OTHERWISE... GENERALLY VFR CONDITIONS EXPECTED UNTIL LATER TONIGHT WHEN LOW STRATUS WILL AGAIN BE LIKELY FROM KFAY TO KRDU TO KRWI BETWEEN 09Z-12Z OR SO. THIS WILL BURN OFF MONDAY MORNING BY AROUND 15Z-16Z... WITH ANOTHER CHANCE OF THUNDERSTORMS DURING THE AFTERNOON AND EVENING AT ALL TAF SITES. TUESDAY THROUGH FRIDAY... GENERALLY VFR CONDITIONS EXPECTED OUTSIDE OF THE CHANCE OF MAINLY AFTERNOON AND EVENING THUNDERSTORMS MAINLY IN THE EAST ON TUESDAY AND WEDNESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF SHORT TERM...DJF/BLS LONG TERM...BLS AVIATION...PWB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
729 PM EDT SUN JUL 21 2013 .SYNOPSIS... FAIRLY SEASONABLE TEMPERATURES AND A NORMAL SCATTERING OF AFTERNOON STORMS ARE EXPECTED THE NEXT SEVERAL DAYS...COMPLIMENTS OF BERMUDA HIGH PRESSURE. A COLD FRONT DROPPING CLOSE TO THE REGION ON THURSDAY WILL STALL AND KEEP THE WEATHER A BIT MORE UNSETTLED. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 730 PM SUNDAY...UNLIKE LAST NIGHT WHERE CONVECTION FELL APART VERY QUICKLY DURING THE EVENING...WE SHOULD SEE SHOWER AND EMBEDDED T-STORM ACTIVITY PERSIST THROUGH THE EVENING HOURS...DRIVEN BY UPPER LEVEL DISTURBANCES EMBEDDED IN THE WESTERLY FLOW ALOFT. EARLIER SYNOPTIC MODELS PLACED ONE SIGNIFICANT UPPER DISTURBANCE ACROSS THE CAPE FEAR REGION OF SE NORTH CAROLINA CURRENTLY...BUT LOOKING AT WATER VAPOR IMAGERY AND RADAR SHOWS THIS PROBABLY IS NOT CORRECT. THE 21Z RUC APPEARS TO HAVE A BETTER HANDLE ON THE SITUATION AND PLACES THE BEST 500 MB VORTICITY ALONG AN AXIS FROM CHARLOTTE TO SOUTH OF COLUMBIA...MATCHING RADAR IMAGERY MUCH BETTER. THIS DISTURBANCE WILL HAVE ACCESS TO SUFFICIENT INSTABILITY OVER THE NEXT 4 HOURS TO CONTINUE PRODUCING SHOWERS AND EMBEDDED T-STORMS...WITH THE BULK OF THE CONVECTION SHIFTING EAST AND OFFSHORE AROUND MIDNIGHT. BESIDES ADJUSTING POP/SKY/WIND FIELDS TO BETTER FIT THE RUC/HRRR IDEAS OVER THE NEXT 4-6 HOURS...NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS... SCATTERED MODERATE AND ISOLATED HEAVY SHOWERS AND TSTMS WERE TRACKING ENE AROUND 15 MPH ACROSS THE FORECAST AREA AT 3PM. SQUELCHED SURFACE HEATING HAS THUS FAR RESULTED IN LOWER SURFACE BASED CAPES AND VIRTUALLY NO SEA BREEZE CONVERGENCE UP TO THIS POINT WHICH HAS PLAYED A SIGNIFICANT ROLE IN REDUCED CONVECTIVE COVERAGE AND INTENSITY CONSIDERING THE AVAILABILITY OF ABUNDANT COLUMN MOISTURE. AS A RESULT ONLY LOW-END RAINFALL ACCUMULATIONS HAVE OCCURRED SO FAR GIVEN PRECIPITABLE WATERS IN EXCESS OF 2". NOT EXPECTING A GREAT DEAL OF CHANGE TO RADAR TRENDS THROUGH THE AFTERNOON ALTHOUGH WE MAY SEE A BIT MORE HEAVIER CELLS PICK UP A BIT AS MID AFTERNOON JULY SUNSHINE POKES THROUGH AT TIMES...AIDING IN LOCALIZED POCKETS OF GREATER LOW-LEVEL INSTABILITY. STILL THINK LOSS OF HEATING INTO EARLY EVENING WILL LESSEN COVERAGE OVERALL. THERE IS ONE SHORT-WAVE IMPULSE NOTED IN VAPOR ANIMATIONS THAT COULD SUSTAIN ACTIVITY INTO TONIGHT PRESENTLY OVER GEORGIA HEADING INTO SOUTH CAROLINA. FOR THIS REASON AND THE FACT THAT WE HAVE A MODERATELY BUOYANT AND WET ATMOSPHERE WHICH MAY EASILY BE TRIGGERED BY OUTFLOWS...WILL SUSTAIN MENTIONABLE POPS INTO THE TONIGHT PERIOD. BELIEVE WE MAY SEE 1200-1800 FOOT STRATUS CLOUDS OVERNIGHT AND HAVE OPTED FOR THE SLIGHTLY WARMER SIDE OF THE GUIDANCE ENVELOPE...MAINLY MID 70S MOST LOCATIONS AND UPPER 70S ALONG THE IMMEDIATE COAST. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...COPIOUS MOISTURE REMAINS IN PLACE ON MONDAY WITH PRECIPITABLE WATER STILL ABOVE 2 INCHES. WHILE WIDESPREAD CLOUD COVER INHIBITED INSOLATION AND THUS CONVECTIVE COVERAGE TODAY THIS APPEARS A LITTLE LESS LIKELY MONDAY.FCST SOUNDINGS LESS INDICATIVE OF WIDESPREAD SC EARLY IN THE DAY SO EXPECT BETTER HEATING AND THUS COVERAGE OF STORMS. ITS HARD TO PIN DOWN ANY FAVORED AREAS FOR HIGHER POPS...ABUT A LATE DAY UPPER VORT AND SFC TROUGH MAY FOCUS ACTIVITY OVER WESTERN ZONES EVEN AS A LARGER SCALE DIURNAL WANING IS UNDERWAY. A STRONGER VORT WILL SCOOT BY TO OUR NORTH ON TUESDAY...PERHAPS AROUND MIDDAY. IN ITS WAKE WILL BE A SUPPRESSING EFFECT ON CONVECTION AND SOME 20-30 POPS SEEM ALL THAT IS WARRANTED. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...PATTERN ALOFT REMAINS AMPLIFIED THROUGH THE PERIOD WITH 5H TROUGHING OVER THE EAST COAST AND RIDGING OUT WEST. THIS MAINTAINS ACTIVE WEATHER ACROSS THE SOUTHEAST WITH PIEDMONT TROUGH AND SEA BREEZE BEING THE FOCUS ON WED. FROM THU ON WEAK COLD FRONT MOVES INTO THE REGION BUT STALLS WITH FLOW ALOFT BECOMING PARALLEL TO THE SURFACE BOUNDARY. HAVE A HARD TIME BELIEVING THE FRONT WILL MAKE IT TO THE COAST FOR ANY LENGTH OF TIME WITH THE 5H TROUGH AXIS REMAINING WEST OF THE AREA. WEAK WAVES DEVELOPING ON THE FRONT WILL BRIEFLY PUSH THE BOUNDARY TO THE COAST BEFORE ALLOWING IT TO RETURN INLAND. IN ADDITION TO NUDGING THE FRONT EAST OR WEST THESE WAVES SHOULD HELP GENERATE AND ENHANCE CONVECTION. TIMING THE FEATURES AT THIS POINT IS DIFFICULT AT BEST SO WILL MAINTAIN CHANCE POP THROUGH THE FORECAST PERIOD. FRONT WILL SLOWLY DISSIPATE DURING THE SECOND HALF OF THE PERIOD...EVENTUALLY MERGING WITH THE PIEDMONT TROUGH. NEXT WEEKEND A SHORTWAVE MOVING INTO THE MS VALLY INDUCES A SURFACE LOW WHICH THEN LIFTS NORTHEAST THROUGH THE OH VALLEY. COLD FRONT ASSOCIATED WITH THE LOW MOVES INTO THE CAROLINAS LATE IN THE PERIOD. STRONGER 5H TROUGH SUGGESTS THIS FRONT MAY HAVE A BETTER CHANCE OF REACHING OR MOVING OFF THE COAST. AT THE VERY LEAST IT WILL RESULT IN AN INCREASE IN PRECIP CHANCES FOR THE WEEKEND...ESPECIALLY SUN. DAILY CONVECTION AND CLOUD COVER WILL KEEP HIGHS NEAR TO SLIGHTLY BELOW CLIMO WHILE SOUTHERLY FLOW...MOISTURE AND LEFT OVER DEBRIS CLOUD KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 00Z...DUE TO SCATTERED NATURE OF SHOWER ACTIVITY WILL ELECT TO INDICATE VCSH IN TAFS THIS EVENING AT ALL TERMINALS ALTHOUGH THE CHANCE OF ANY TERMINAL BEING AFFECTED IS RATHER SMALL. SHOWERS WILL GRADUALLY DISSIPATE BY MIDNIGHT LOCAL OVER LAND THEN BEGIN TO DEVELOP IN THE COASTAL WATERS. TEMPO MVFR CIGS WILL BE POSSIBLE AT THE COASTAL TERMINALS TERMINALS THIS EVENING. MVFR CIGS WILL BECOME MORE LIKELY BY MIDNIGHT LOCAL AT THE COASTAL TERMINALS. VSBYS SHOULD DROP TO MVFR IN BR AT KFLO/KLBT BY MIDNIGHT LOCAL WITH SCATTERED IFR STRATUS. AFTER MIDNIGHT THERE IS INCREASING CONFIDENCE OF IFR CIGS AT ALL TERMINALS. ANY IFR CIGS SHOULD RISE TO MVFR BY 14Z WITH VFR DEVELOPING LATE MORNING INTO EARLY AFTERNOON. SHOULD BE A GOOD CHANCE OF VCSH AT THE COASTAL TERMINALS BY NOON LOCAL WITH VCTS DEVELOPING AT KFLO/KLBT WITH THE APPROACH OF AN UPPER IMPULSE. EXTENDED OUTLOOK...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THURSDAY...WITH BRIEF LOCALIZED PERIODS OF MVFR/IFR POSSIBLE. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM/THROUGH TONIGHT/... AS OF 730 PM SUNDAY...WINDS FINALLY SURGED UP IN THE LAST FEW HOURS BUT ARE STILL WELL BELOW ADVISORY THRESHOLDS. RECENT GUSTS INCLUDE 21 KNOTS AT THE FRYING PAN SHOALS BUOY...NORTH MYRTLE BEACH...AND OAK ISLAND...20 KNOTS ON BALD HEAD ISLAND...AND 19 KNOTS IN GEORGETOWN. THESE STRONGER SOUTHWEST WINDS MAY CONTINUE THROUGH 11 PM OR MIDNIGHT BEFORE A LANDBREEZE PRODUCES MUCH LIGHTER WEST-SOUTHWEST WINDS NEAR THE BEACHES...SPREADING OUT AWAY FROM THE COAST OVERNIGHT. NO OTHER SIGNIFICANT CHANGES ARE NECESSARY TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS... BECAUSE INLAND HEATING WAS PREVENTED BY THE EXTENSIVE CLOUD COVER...THE SEA BREEZE NEVER QUITE GOT CRANKING AND COASTAL WATER WINDS HAVE REMAINED AROUND 15 KNOTS WHILE SEAS EVEN OUT BEYOND 20NM MILES HAVE DAMPENED TO 4 FEET. THEREFOR WILL DROP THE EXERCISE CAUTION HEADLINE WITH THE AFTERNOON ISSUANCE OF THE CWF. SEAS WILL BE COMPRISED OF S WAVE 3 FT AT 6 SECONDS AND SE WAVES 1-2 FEET EVERY 8-9 SECONDS. A FEW TSTMS OR HEAVY SHOWERS MAY IMPACT THE WATERS THROUGH THE NEAR TERM PERIOD...LOCALLY REDUCING VSBYS AND IMPARTING CLOUD TO SEA STRIKES. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...WEAK WAVE OF LOW PRESSURE NEAR DELMARVA WILL VEER LOCAL FLOW SLIGHTLY TO A MORE WESTERLY DIRECTION THAN THE TYPICAL SW FOR PART OF MONDAY. LATER IN THE DAY SW FLOW GETS ESTABLISHED WITH ABOUT A 5KT INC IN SPEED. THIS TREND WILL CONTINUE INTO MONDAY NIGHT BUT NOT TO WHERE CAUTIONARY HEADLINES WARRANTED AS SEAS NOT EXPECTED TO BUILD QUITE ENOUGH WITHIN 20NM BORDER. PIEDMONT TROUGHINESS DEVELOPS LATER FRIDAY AND SHOULD MAINTAIN SLIGHTLY HIGHER WIND SPEEDS THAN WHAT SEASONABLE...15 TO 20KT MOST ZONES. A LITTLE LIGHTER FLOW OVER SRN LEGS WHICH SHOULD PREVENT 5 FT SEAS OFF GTOWN. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD WITH WATERS IN BETWEEN BERMUDA HIGH AND PIEDMONT TROUGH/WEAK COLD FRONT. WINDS AND SEAS WILL BE HIGHEST EARLY IN THE PERIOD. GRADIENT RELAXES AS FRONT/TROUGH MOVE CLOSER TO THE COAST AND WEAK SURFACE WAVES DEVELOP ON THE BOUNDARY. SPEEDS WILL BE 10 TO 15 KT WED THEN DECREASE TO AROUND 10 KT FOR THU AND FRI. SEAS WILL FALL FROM 3 TO 4 FT ON WED TO AROUND 2 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...COASTAL FLOOD ADVISORY FROM 8 PM TO 11 PM EDT THIS EVENING FOR NCZ107. MARINE...NONE. && $$ SYNOPSIS...MBB NEAR TERM...MJC/TRA SHORT TERM...MBB LONG TERM...III AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 PM EDT SAT JUL 20 2013 .SYNOPSIS... A SURFACE TROUGH OF LOW PRESSURE...IN A MOIST AIR MASS...WILL REMAIN OVER THE REGION AT LEAST THROUGH THE MIDDLE OF THE UPCOMING WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1055 AM SATURDAY... CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING... AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA... TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 245 AM SATURDAY... SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE 2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS COULD RESULT IN LOCALIZED FLOODING. HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 230 PM SATURDAY... MONDAY THROUGH TUESDAY NIGHT... EARLY THIS WEEK...BROAD TROUGHING WILL CONTINUE TO EVOLVE OVER THE EASTERN US... WHILE A QUASI-STATIONARY FRONTAL ZONE NEAR THE MASON-DIXON LINE REMAINS TO OUR NORTH. A PAIR OF WEAK UPPER DISTURBANCES SHOULD IMPACT THE AREA AS MONDAY AND TUESDAY AS THE UPPER TROUGH BEGINS A SLOW AMPLIFICATION. THE FIRST DISTURBANCE WILL BE THE REMNANTS OF A WEAK UPPER LOW CURRENTLY OVER LOUISIANA...WHICH DYNAMIC TROPOPAUSE MAPS SHOW LIFTING ACROSS CENTRAL AND WESTERN NC MONDAY AFTERNOON. THE SECOND AND LIKELY STRONGER DISTURBANCE IS ASSOCIATED WITH ENERGY MAKING ITS WAY ACROSS INTO THE NORTHERN PLAINS. CONFIDENCE IN THE TIMING/IMPACTS OF EITHER OF THESE DISTURBANCES IS ONLY MEDIUM AT DAYS 3 AND 4...BUT THEY WOULD LIKELY ENHANCE CONVECTION IN WHAT WILL BE A MODERATELY UNSTABLE AIRMASS WITH DEWPOINTS IN THE LOWER 70S AND PW BACK UP TO NEAR 2 INCHES. WILL INDICATE THE HIGHEST POPS OVER THE WESTERN PIEDMONT MONDAY AND OVER THE COASTAL PLAIN ON TUESDAY. WHILE STRONG STORMS WILL BE POSSIBLE...WEAK FLOW ALOFT DOESN`T SUPPORT A SIGNIFICANT SEVERE THREAT. HIGHS IN THE UPPER 80S AND AROUND 90 EACH DAY...WITH A SLIGHT CHANCE OF A LINGERING STORM OVERNIGHT. WEDNESDAY THROUGH SATURDAY... MODELS ARE IN GOOD AGREEMENT ON THE MEAN TROUGH PERSISTING OVER THE EASTERN US THROUGH THE END OF THE WEEK...THOUGH WITH A FAIR AMOUNT OF UNCERTAINTY REGARDING THE DETAILS OF NUMEROUS DISTURBANCES MOVING FROM THE MIDWEST TO THE SOUTHEASTERN AND MID-ATLANTIC STATES. A WEAK FRONTAL ZONE TO OUR NORTH IS PROJECTED TO SLIP SOUTH AND POTENTIALLY MERGE WITH PIEDMONT TROUGH AS THE UPPER TROUGH BECOMES SLIGHTLY MORE AMPLIFIED. NO SIGNIFICANT AIRMASS CHANGE IS EXPECTED WITH THE FRONT...AND WHILE SCATTERED CONVECTION SHOULD BE PRIMARILY DIURNAL EACH DAY...CYCLONIC FLOW ALOFT AND THE PRESENCE OF THE BETTER LOW LEVEL CONVERGENCE MAY SUPPORT BETTER POTENTIAL FOR CONVECTION CONTINUING OVERNIGHT. TEMPS WILL CONTINUE TO NEAR NORMAL...UPPER 80S FOR HIGHS AND LOWER 70S FOR LOWS. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 155 PM SATURDAY... MOSTLY VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY PART OF THE 18Z VALID TAF PERIOD...AS LINGERING MVFR CEILINGS CONTINUE TO RISE AND SCATTER EARLY THIS SATURDAY AFTERNOON. IN VICINITY OF THE TRIAD...AND ALONG THE INTERSTATE 85 CORRIDOR...THERE IS A BETTER CHANCE COMPARED TO THE REST OF CENTRAL NORTH CAROLINA OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING. OVERNIGHT...THE PRIMARY AVIATION ISSUE WILL BE THE DEVELOPMENT OF LOW CEILINGS. SOME FORECAST GUIDANCE SUGGESTS THE PROBABILITY OF LOW CLOUDS EARLY SUNDAY TO BE AT LEAST AS HIGH AS THIS SATURDAY MORNING...AND AS A RESULT ANTICIPATE FAIRLY WIDESPREAD IFR CONDITIONS AROUND SUNRISE SUNDAY. CEILINGS SHOULD GRADUALLY RISE INTO MVFR AND LIKELY VFR THROUGH THE MORNING SUNDAY...BEGINNING AFTER 13Z TO 14Z. BEYOND THE 18Z VALID TAF PERIOD...A MOIST AIR MASS CONTINUES OVER CENTRAL NORTH CAROLINA. GIVEN LITTLE AIR MASS CHANGE...AVIATION INTERESTS SHOULD PREPARE FOR AT LEAST SCATTERED...MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EACH DAY...WITH A FEW SHOWERS AND STORMS POSSIBLY LINGERING THROUGH THE OVERNIGHT HOURS. LATE NIGHT AND EARLY MORNING FOG WILL HAMPER VISIBILITIES ESPECIALLY WHERE RAIN TENDS TO CONCENTRATE AND OVERNIGHT WINDS TURN LIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...CBL/DJF SHORT TERM...BLS LONG TERM...BLS AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
155 PM EDT SAT JUL 20 2013 .SYNOPSIS... A SURFACE TROUGH OF LOW PRESSURE...IN A MOIST AIR MASS...WILL REMAIN OVER THE REGION AT LEAST THROUGH THE MIDDLE OF THE UPCOMING WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1055 AM SATURDAY... CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING... AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA... TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 245 AM SATURDAY... SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE 2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS COULD RESULT IN LOCALIZED FLOODING. HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 245 AM SATURDAY... MONDAY AND MONDAY NIGHT: A BACKDOOR COLD FRONT IS EXPECTED TO STALL OVER VA ON MONDAY WITH THE H85 TROUGH AXIS EXTENDING EAST THROUGH CENTRAL NC AND THE MAIN UPPER LEVEL TROUGH OVER THE APPALACHIANS. THE ATMOSPHERE WILL BE SUFFICIENTLY MOIST AND UNSTABLE TO ALLOW CONVECTION TO DEVELOP DURING THE AFTERNOON AS WEAK UPPER LEVEL DISTURBANCES MOVE OVER THE AREA. AHEAD OF THE MAIN TROUGH...THE 00Z GFS SHOWS A H3 SHORTWAVE DISTURBANCE MOVING NORTHEAST FROM THE LOW OVER LOUISIANA AROUND THE BASE OF THE TROUGH AND OVER NC MONDAY EVE/NIGHT. DEPENDING ON THE TIMING...THIS FEATURE COULD ENHANCE CONVECTION LATE MONDAY...OR HELP SUSTAIN CONVECTION INTO THE OVERNIGHT HOURS. GIVEN THE UNCERTAINTY...WILL KEEP HIGHEST PRECIP CHANCES DURING THE AFT/EVE HOURS AND ONLY INCREASE THEM SLIGHTLY DURING THE 03Z-07Z TIMEFRAME. HIGHS MONDAY STILL EXPECTED TO BE IN THE MID TO UPPER 80S...WITH OVERNIGHT LOWS MAINLY IN THE LOW TO MID 70S. TUESDAY THROUGH FRIDAY: THE UPPER LEVEL TROUGH AXIS SHOULD SHIFT EAST OVER CENTRAL NC ON TUESDAY WHERE IT WILL LINGER THROUGH FRIDAY. AS THE H85 TROUGH SLOWLY DRIFTS EAST ON TUESDAY...WINDS OVER THE WESTERN PORTIONS OF THE AREA MAY SHIFT FROM SOUTHWEST TO MORE WESTERLY. THIS WOULD HELP DRY OUT THE MID LEVELS A BIT LATE TUESDAY THROUGH WEDNESDAY...THUS DECREASING PW VALUES SOME. MEANWHILE...THERE IS A DESCENT CHANCE THE EAST WILL REMAIN UNDER SW FLOW...WITH BETTER MOISTURE ADVECTION AND GREATER INSTABILITY. MID AND UPPER LEVEL DISTURBANCES MOVING OVER NC DURING THIS PERIOD WILL LIKELY HELP GENERATE DIURNALLY DRIVEN CONVECTION. ALTHOUGH GENERALLY CHANCES MAY BE SOMEWHAT BETTER IN THE EAST...CONFIDENCE WITH REGARD TO LOCATION AND COVERAGE OF THE CONVECTION REMAINS LOW AT THIS TIME...THUS WILL CARRY CHANCE POPS DURING THE AFT/EVE ACROSS THE ENTIRE AREA THROUGH THE PERIOD. WILL CONTINUE THE PERSISTENCE TEMP FORECAST...WITH HIGHS IN THE MID TO UPPER 80S AND LOWS IN THE LOW TO MID 70S. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 155 PM SATURDAY... MOSTLY VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY PART OF THE 18Z VALID TAF PERIOD...AS LINGERING MVFR CEILINGS CONTINUE TO RISE AND SCATTER EARLY THIS SATURDAY AFTERNOON. IN VICINITY OF THE TRIAD...AND ALONG THE INTERSTATE 85 CORRIDOR...THERE IS A BETTER CHANCE COMPARED TO THE REST OF CENTRAL NORTH CAROLINA OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING. OVERNIGHT...THE PRIMARY AVIATION ISSUE WILL BE THE DEVELOPMENT OF LOW CEILINGS. SOME FORECAST GUIDANCE SUGGESTS THE PROBABILITY OF LOW CLOUDS EARLY SUNDAY TO BE AT LEAST AS HIGH AS THIS SATURDAY MORNING...AND AS A RESULT ANTICIPATE FAIRLY WIDESPREAD IFR CONDITIONS AROUND SUNRISE SUNDAY. CEILINGS SHOULD GRADUALLY RISE INTO MVFR AND LIKELY VFR THROUGH THE MORNING SUNDAY...BEGINNING AFTER 13Z TO 14Z. BEYOND THE 18Z VALID TAF PERIOD...A MOIST AIR MASS CONTINUES OVER CENTRAL NORTH CAROLINA. GIVEN LITTLE AIR MASS CHANGE...AVIATION INTERESTS SHOULD PREPARE FOR AT LEAST SCATTERED...MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EACH DAY...WITH A FEW SHOWERS AND STORMS POSSIBLY LINGERING THROUGH THE OVERNIGHT HOURS. LATE NIGHT AND EARLY MORNING FOG WILL HAMPER VISIBILITIES ESPECIALLY WHERE RAIN TENDS TO CONCENTRATE AND OVERNIGHT WINDS TURN LIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...CBL/DJF SHORT TERM...CBL LONG TERM...KC AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EDT SAT JUL 20 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH TODAY. AN UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY OVER THE REGION SUNDAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1055 AM SATURDAY... CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING... AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA... TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 245 AM SATURDAY... SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE 2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS COULD RESULT IN LOCALIZED FLOODING. HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 245 AM SATURDAY... MONDAY AND MONDAY NIGHT: A BACKDOOR COLD FRONT IS EXPECTED TO STALL OVER VA ON MONDAY WITH THE H85 TROUGH AXIS EXTENDING EAST THROUGH CENTRAL NC AND THE MAIN UPPER LEVEL TROUGH OVER THE APPALACHIANS. THE ATMOSPHERE WILL BE SUFFICIENTLY MOIST AND UNSTABLE TO ALLOW CONVECTION TO DEVELOP DURING THE AFTERNOON AS WEAK UPPER LEVEL DISTURBANCES MOVE OVER THE AREA. AHEAD OF THE MAIN TROUGH...THE 00Z GFS SHOWS A H3 SHORTWAVE DISTURBANCE MOVING NORTHEAST FROM THE LOW OVER LOUISIANA AROUND THE BASE OF THE TROUGH AND OVER NC MONDAY EVE/NIGHT. DEPENDING ON THE TIMING...THIS FEATURE COULD ENHANCE CONVECTION LATE MONDAY...OR HELP SUSTAIN CONVECTION INTO THE OVERNIGHT HOURS. GIVEN THE UNCERTAINTY...WILL KEEP HIGHEST PRECIP CHANCES DURING THE AFT/EVE HOURS AND ONLY INCREASE THEM SLIGHTLY DURING THE 03Z-07Z TIMEFRAME. HIGHS MONDAY STILL EXPECTED TO BE IN THE MID TO UPPER 80S...WITH OVERNIGHT LOWS MAINLY IN THE LOW TO MID 70S. TUESDAY THROUGH FRIDAY: THE UPPER LEVEL TROUGH AXIS SHOULD SHIFT EAST OVER CENTRAL NC ON TUESDAY WHERE IT WILL LINGER THROUGH FRIDAY. AS THE H85 TROUGH SLOWLY DRIFTS EAST ON TUESDAY...WINDS OVER THE WESTERN PORTIONS OF THE AREA MAY SHIFT FROM SOUTHWEST TO MORE WESTERLY. THIS WOULD HELP DRY OUT THE MID LEVELS A BIT LATE TUESDAY THROUGH WEDNESDAY...THUS DECREASING PW VALUES SOME. MEANWHILE...THERE IS A DESCENT CHANCE THE EAST WILL REMAIN UNDER SW FLOW...WITH BETTER MOISTURE ADVECTION AND GREATER INSTABILITY. MID AND UPPER LEVEL DISTURBANCES MOVING OVER NC DURING THIS PERIOD WILL LIKELY HELP GENERATE DIURNALLY DRIVEN CONVECTION. ALTHOUGH GENERALLY CHANCES MAY BE SOMEWHAT BETTER IN THE EAST...CONFIDENCE WITH REGARD TO LOCATION AND COVERAGE OF THE CONVECTION REMAINS LOW AT THIS TIME...THUS WILL CARRY CHANCE POPS DURING THE AFT/EVE ACROSS THE ENTIRE AREA THROUGH THE PERIOD. WILL CONTINUE THE PERSISTENCE TEMP FORECAST...WITH HIGHS IN THE MID TO UPPER 80S AND LOWS IN THE LOW TO MID 70S. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... AS OF 1055 AM SATURDAY... 24-HR TAF PERIOD: MVFR STRATUS WILL SLOWLY LIFT DURING THE REST OF THE MORNING. ISOLATED-TO-SCATTERED SHOWERS AND THUNDERSTORMS SHOULD OCCUR THIS AFTERNOON AND EVENING...WITH THE HIGHEST PROBABILITIES IN VICINITY OF INTERSTATE 85. LOOKING AHEAD: AN UPPER LEVEL TROUGH WILL GRADUALLY AMPLIFY OVER THE REGION SUNDAY THROUGH EARLY NEXT WEEK. THIS WILL RESULT IN AN ABOVE NORMAL COVERAGE AND CHANCES FOR SHOWERS/THUNDERSTORMS DURING THE AFTERNOON AND EVENING HOURS SUNDAY THROUGH WEDNESDAY. A POTENTIAL FOR SUB-VFR FOG/STRATUS WILL ALSO PERSIST DURING THE EARLY MORNING HOURS... PRIMARILY IN THE 06-11Z TIME FRAME. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL/DJF NEAR TERM...CBL/DJF SHORT TERM...CBL LONG TERM...KC AVIATION...CBL/DJF
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
409 AM EDT SAT JUL 20 2013 .SYNOPSIS... A TYPICAL SUMMER PATTERN OF HIGH PRESSURE OFFSHORE AND A TROUGH OF LOW PRESSURE INLAND WILL PERSIST THROUGH THE WEEKEND. A COLD FRONT WILL MOVE INTO THE AREA BY WEDNESDAY OR THURSDAY OF NEXT WEEK. && .NEAR TERM /TODAY/... AS OF 355 AM SATURDAY...BAND OF SHOWERS MOVING UP THE COAST THIS MORNING...WHICH WAS WELL DEPICTED BY THE HRRR AND A NUMBER OF OTHER HIGH RESOLUTION MODELS. THIS ACTIVITY SHOULD LINGER NEAR OR JUST OFFSHORE THROUGH THE EARLY MORNING HOURS BEFORE TRANSITIONING INLAND AS SOME ADDITIONAL MID-LEVEL ENERGY MOVES NORTHEAST AROUND THE PERIPHERY OF BROAD BERMUDA RIDGE TO THE EAST AND SURFACE TROUGH OVER THE PIEDMONT SHARPENS DURING THE AFTERNOON. ADDITIONAL SHOWERS/TSTMS WILL DEVELOP DURING THE MID TO LATE AFTERNOON HOURS WITH THE FAVORED LOCATION BEING THE SOUTHERN COASTAL PLAINS AND SOUTHERN COASTAL AREAS. IT WILL BE ANOTHER WARM AND HUMID DAY WITH HIGHS IN THE UPPER 80S TO LOWER 90S IN MOST AREAS. && .SHORT TERM /TONIGHT/... AS OF 400 AM SATURDAY...NOT ALOT OF CHANGE TO THE FORECAST TONIGHT. THE COMBINATION OF DEEP MOISTURE AND ADDITIONAL SHORTWAVE ENERGY EMBEDDED IN SOUTHWEST FLOW WILL LEAD TO A LOW CHANCE POPS THROUGH THE NIGHT TONIGHT. MINIMUM TEMPERATURES TONIGHT SHOULD BE IN THE 73 TO 77 DEGREE RANGE. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 315 AM SAT...SW FLOW PERSISTS SAT NIGHT INTO SUN WITH DEWPOINTS/PWATS RISING. SHORT TERM MODELS CONTINUE IN DECENT AGREEMENT ON POTENTIAL FOR SHOWERS/TSTORMS RIDING UP THE COAST EARLY SUN AS AREA OF CONVERGENCE EXISTS WITH WEAK SHORTWAVE ENERGY MOVING NORTHEAST FROM OFF CHS/ILM TOWARDS THE CWA. WILL MAINTAIN SLIGHT CHANCE POPS FOR COASTAL AREAS WITH CHANCE POPS JUST OVER THE WATERS. PRECIP CHANCES INCREASE SUN AFTERNOON AS A WEAK COOL FRONT APPROACHES AND SETTLES OVER EASTERN NC BEFORE WASHING OUT LATER IN THE WEEK. UPPER TROUGH OVER THE GREAT LAKES WILL DIG SOUTH MON/TUES AND PERSIST OVER THE EASTERN CONUS THROUGH LATE WEEK...REINFORCING THE RAIN CHANCES THROUGH THE PERIOD. WEAK PERTURBATIONS IN THE MID AND UPPER LEVELS WILL ALSO AID CONVECTION DURING THE EXTENDED PERIOD. PWATS INCREASE TO 2 INCHES OR GREATER SUN AND REMAIN HIGH THROUGH MID TO LATE WEEK. HAVE CONTINUED THE TREND OF DIURNAL CONVECTION EACH DAY WITH NEAR 50 PERCENT POPS INLAND DURING THE AFTERNOON WITH 25-30 PERCENT POPS OVERNIGHT...WITH THIS PATTERN EXPECTED THROUGH LATE WEEK. SEVERE WEATHER IS NOT EXPECTED AS SHEAR WILL BE MINIMAL...THOUGH WITH ANY PULSE STORM AN ISOLATED STRONG TO SEVERE WIND GUST IS POSSIBLE. WITH OVERALL WEAK STEERING FLOW...ANY ORGANIZED CONVECTION WILL HAVE HEAVY RAINFALL POTENTIAL ESPECIALLY IF CELLS TRAIN OVER THE SAME AREA. WILL HAVE TO WATCH OUT FOR LOCALIZED FLOODING AS THIS UNSETTLED PATTERN LOOKS TO PERSIST. TEMPS THROUGH THE LONG TERM PERIOD WILL BE CLOSER TO CLIMO...HIGHS IN THE UPPER 80S TO NEAR 90 WITH LOW/MID 70S FOR OVERNIGHT LOWS. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM /TODAY AND TONIGHT/... AS OF 1245 AM SATURDAY...THERE APPEARS TO BE SUFFICIENT MIXING OVERNIGHT TO PRECLUDE MUCH IN THE WAY OF FOG OR STRATUS AS WE KEEP A LIGHT SOUTHWEST WIND OVERNIGHT. SLIGHTLY BETTER CHC OF TSTMS INLAND SAT AFTN WITH CONTINUED INFLUX OF MSTR AND WEAK SHRT WV ENERGY FROM S-SW. SW WINDS MAY GUST UP TO 20 KTS AS WELL DURING AFTN. LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 4 AM SAT...PREDOMINANT VFR CONDITIONS EXPECTED THROUGH THE PERIOD. AN UPPER TROUGH AND ASSOCIATED SFC FRONT APPROACH FROM THE NW SUN BRINGING INCREASING CHANCES OF SCATTERED SHOWERS/TSTORMS FOR THE TERMINALS THROUGH LATE WEEK. COULD SEE BRIEF EARLY MORNING MVFR/IFR VSBYS DURING THE LONG TERM AS FORECAST SOUNDINGS INDICATE GOOD BOUNDARY LAYER MOISTURE TRAPPED UNDER A WEAK SURFACE BASED INVERSION. HOWEVER...BOUNDARY LAYER MIXING MAY BE ENOUGH TO INHIBIT FOG FORMATION...THUS LOW CONFIDENCE IN REDUCED AVIATION CONDITIONS EACH NIGHT. && .MARINE... SHORT TERM /TODAY AND TONIGHT/... AS OF 4 AM SATURDAY...HAVE ADDED THE CURRITUCK BEACH LIGHT TO OREGON INLET LEG TO THE SMALL CRAFT ADVISORY AND HAVE MADE THE EFFECTIVE TIME NOW AS LATEST OBSERVATIONS SHOWING WIND GUSTS AS HIGH AS 25 KNOTS AT DUCK AND UP TO 29 KNOTS AT OREGON INLET. EVEN SEEING WINDS AS HIGH AS 25 KNOTS IN THE PAMLICO SOUND. THE GUSTY SW WINDS WILL CONTINUE TODAY BEFORE SUBSIDING A BIT TONIGHT. SEAS WILL REMAIN AS HIGH AS 6 FEET PER LATEST WAVEWATCH BEFORE SUBSIDING LATE TONIGHT OR EARLY SUNDAY MORNING. LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 330 AM SAT...HIGH PRESSURE OFF THE SE COAST WITH A THERMAL TROUGH INLAND WILL BE THE DOMINANT PATTERN THROUGH MUCH OF THE LONG TERM. PRESSURE GRADIENT REMAINS TIGHT THROUGH EARLY SUNDAY BEFORE WEAKENING DUE TO APPROACHING COOL FRONT DISSIPATING INLAND. SCA CONDITIONS SHOULD DIMINISH ACROSS THE COASTAL WATERS BY SUN AFTERNOON AS SEAS SUBSIDE BELOW 6 FEET. A BREAK IN THE GUSTY SW WINDS MONDAY BEFORE REINFORCING TROUGH/FRONT APPROACH TUES INTO MID WEEK. MARGINAL SCA CONDITIONS COULD DEVELOP ONCE AGAIN AS THE GRADIENT INCREASES TUES NIGHT. NO SIGNIFICANT CHANGES TO THE MEDIUM TERM...BUT HAVE ADJUSTED SEAS DOWN A FOOT FROM WED NIGHT THROUGH THURS NIGHT...WHICH IS IN COLLABORATION WITH NEIGHBORING OFFICES AND OPC. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON EDT SUNDAY FOR AMZ152-154-156-158. SMALL CRAFT ADVISORY FROM NOON TODAY TO 10 PM EDT THIS EVENING FOR AMZ135. && $$ SYNOPSIS...CTC NEAR TERM...CTC SHORT TERM...CTC LONG TERM...DAG AVIATION...CTC/DAG MARINE...CTC/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1250 AM EDT SAT JUL 20 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN EAST OF THE AREA WITH TROUGHING TO THE WEST THROUGH THE WEEKEND AND INTO MIDWEEK. A FRONT WILL APPROACH LATER IN THE WEEK BUT NOT MOVE THROUGH. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1240 AM SATURDAY...DECENT AGREEMENT AMONGST THE 4 KM EMC WRF...HRR-R AND RAP MODELS SHOWING SOME WIDELY SCATTERED SHOWERS AND TSTMS DEVELOPING ALONG THE SOUTHERN COAST AFTER 08Z. THE NAM IS A BIT SLOWER IN THE DEVELOPMENT OF CONVECTION...BUT DOES SHOW T THE PRECIPITATION AREA SPREADING NORTH AND WEST DURING THE MORNING AS SOME MID-LEVEL ENERGY MOVES UP THE COAST AROUND THE PERIPHERY OF LARGE BERMUDA HIGH. HAVE KEPT SLIGHT TO LOW CHC POPS RIGHT ALONG THE IMMEDIATE COAST THROUGH 12Z. WHILE COVERAGE WILL NOT BE PARTICULARLY GREAT...THERE IS SUFFICIENT INSTABILITY AND MOISTURE TO HAVE SOME LOCALIZED DOWNPOURS...PARTICULAR THE SOUTHERN COAST AND SOUTHERN COASTAL PLAINS. NO CHANGES TO OVERNIGHT TEMP FORECAST. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... AS OF 400 PM FRI...DESPITE GENERAL AGREEMENT IN THE OVERALL PATTERN THERE ARE SEVERAL DIFFERENCES IN THE MODELS REGARDING TIMING AND LOCATION OF APPROACHING SHRTWV ENERGY AND PRECIPITATION. SETTLED ON A COMPROMISE SOLUTION BETWEEN THE 12Z GFS AND 12Z NAM SIMILAR TO THE 00Z ECMWF. EXPECT A CHANCE OF PRECIPITATION TO DEVELOP ALONG THE SOUTHEAST COAST LATE TONIGHT INTO TOMORROW MORNING...THEN SHIFTED THE FOCUS FOR ANY SHOWERS AND TSTMS INLAND ALONG THE SEA BREEZE FOR SATURDAY AFTERNOON. MOS GUIDANCE WAS IN CLOSE AGREEMENT AND FOLLOWED A BLEND THROUGH THE PERIOD. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... AS OF 330 PM FRI...SW FLOW INCREASES SAT NIGHT WITH DEWPOINTS/PWATS ON THE RISE. MOST SHORT TERM MODELS IN AGREEMENT ON POTENTIAL FOR SHOWERS/STORMS RIDING UP THE COAST SAT NIGHT AS AREA OF CONVERGENCE EXISTS WITH WEAK SHORTWAVE ENERGY MOVING NORTHEAST. HAVE MAINTAINED SLIGHT CHANCE POPS FOR COASTAL AREAS WITH CHANCE POPS JUST OVER THE WATERS. PRECIP CHANCES INCREASE SUN AS A WEAK COOL FRONT APPROACHES AND SETTLES OVER EASTERN NC BEFORE WASHING OUT MIDWEEK. HOWEVER... IT APPEARS THAT UNSETTLED WEATHER WILL EXIST MID WEEK AND BEYOND AS LATEST TREND IN MODELS INDICATE PERSISTENT LONG WAVE TROUGHINESS ACROSS THE EASTERN CONUS REINFORCING THE RAIN CHANCES. HAVE INC POPS TO HIGH CHANCE MID WEEK DUE TO THESE LATEST TRENDS. FOR SUNDAY...APPROACHING WEAK COOL FRONT ALONG WITH WEAK PERTURBATIONS IN THE MID AND UPPER LEVELS WILL SPARK SCT MAINLY AFTERNOON AND EARLY EVENING CONVECTION...WITH BEST CHANCES ACROSS INLAND LOCALES. SEVERE WEATHER NOT EXPECTED AS SHEAR IS MINIMAL...THOUGH WITH ANY PULSE STORM AN ISOLATED STRONG TO SEVERE WIND GUST IS POSSIBLE. THE SAME HOLDS TRUE FOR THE REST OF THE UPCOMING WEEK WITH ANY AFTERNOON CONVECTION. UPPER TROUGH OVER THE GREAT LAKES WILL DIG SOUTH MON/TUES AND PERSIST OVER THE EASTERN CONUS THROUGH LATE WEEK. PWATS INCREASE TO 2 INCHES OR GREATER LATE THIS WEEKEND AND REMAIN HIGH THROUGH MID TO LATE WEEK. WITH OVERALL WEAK STEERING FLOW...ANY ORGANIZED CONVECTION WILL HAVE HEAVY RAINFALL POTENTIAL ESPECIALLY IF CELLS TRAIN OVER THE SAME AREA. WILL HAVE TO WATCH OUT FOR LOCALIZED FLOODING AS THIS UNSETTLED PATTERN LOOKS TO PERSIST. TEMPS THROUGH THE LONG TERM PERIOD WILL BE CLOSER TO CLIMO...HIGHS IN THE UPPER 80S TO NEAR 90 WITH LOW/MID 70S FOR OVERNIGHT LOWS. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM /THROUGH 00Z SUNDAY/... AS OF 1245 AM SATURDAY...THERE APPEARS TO BE SUFFICIENT MIXING OVERNIGHT TO PRECLUDE MUCH IN THE WAY OF FOG OR STRATUS AS WE KEEP A LIGHT SOUTHWEST WIND OVERNIGHT. SLIGHTLY BETTER CHC OF TSTMS INLAND SAT AFTN WITH CONTINUED INFLUX OF MSTR AND WEAK SHRT WV ENERGY FROM S-SW. SW WINDS MAY GUST UP TO 20 KTS AS WELL DURING AFTN. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 330 PM FRI...PREDOMINANT VFR CONDITIONS EXPECTED THROUGH THE PERIOD. COULD SEE MVFR/IFR VSBYS DURING THE EARLY MORNING HOURS AS FORECAST SOUNDINGS INDICATE GOOD MOISTURE TRAPPED UNDER THE SURFACE BASED INVERSION WITH LIGHT WINDS...ESPECIALLY FOR AREAS THAT RECEIVE RAINFALL DURING THE DAY. AN UPPER TROUGH AND ASSOCIATED SFC FRONT APPROACH FROM THE NW SUN BRINGING INCREASING CHANCES OF SCATTERED SHOWERS/TSTORMS FOR THE TERMINALS THROUGH MID TO LATE WEEK. && .MARINE... SHORT TERM /THROUGH SATURDAY/... AS OF 1245 AM SATURDAY...MODERATE SW WINDS CONTINUE OVER THE COASTAL WATERS WITH GUSTS INTO THE LOWER 20S IN MANY AREAS. SEAS CONTINUE AT 1 TO 3 FEET NORTH AND UP TO 4 FEET SOUTHERN WATERS. WILL MONITOR TRENDS TO SEE IF SCA NEED TO BE STARTED EARLIER. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 330 PM FRI...HIGH PRESSURE OFF THE SE COAST WITH A THERMAL TROUGH INLAND WILL BE THE DOMINANT PATTERN THROUGH MUCH OF THE LONG TERM. PRESSURE GRADIENT REMAINS TIGHT THROUGH EARLY SUNDAY BEFORE WEAKENING DUE TO APPROACHING COOL FRONT WASHING OUT AND DISSIPATING. SCA CONDITIONS SHOULD DIMINISH FOR PAMLICO SOUND SAT NIGHT... WITH COASTAL WATERS SEEING IMPROVING CONDITIONS BY SUN AFTERNOON AS SEAS SUBSIDE BELOW 6 FEET. A BREAK IN THE GUSTY SW WINDS MONDAY BEFORE REINFORCING TROUGH/FRONT APPROACH TUE INTO MID WEEK. MARGINAL SCA CONDITIONS COULD DEVELOP ONCE AGAIN AS THE GRADIENT INCREASES. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON EDT SUNDAY FOR AMZ152-154-156-158. SMALL CRAFT ADVISORY FROM NOON TODAY TO 10 PM EDT THIS EVENING FOR AMZ135. && $$ SYNOPSIS...CGG NEAR TERM...CTC SHORT TERM...CGG LONG TERM...DAG/TL AVIATION...CTC/DAG/TL MARINE...CTC/DAG/TL/BM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
956 PM CDT SUN JUL 21 2013 .UPDATE... ISSUED AT 945 PM CDT SUN JUL 21 2013 DEEP CONVECTION WEAKENED EARLY THIS EVENING AS IT MOVED INTO THE FAR WESTERN FORECAST AREA. T IS NOW VERY ISOLATED WITH STRONGEST CELL JUST NORTH OF LAKOTA. LOW LEVEL JET FORECAST TO INCREASE WITH BEST CONVERGENCE ALONG INTERNATIONAL BORDER AREA OF MN OVERNIGHT. HAVE MAINTAIN HIGHEST POPS THIS AREA THROUGH MOST OF THE NIGHT. ELSEWHERE STORM POTENTIAL MORE IN QUESTION AND HAVE OVERALL DECREASED POPS SIGNIFICANTLY ACROSS SOUTH HALF OF FA WITH LACK OF CONVERGENCE AND FAVORED MID LEVEL SUPPORT IN CANADA. ANY OTHER CHANGES TO FORECAST MINOR. UPDATE ISSUED AT 633 PM CDT SUN JUL 21 2013 LINE OF DEEP CONVECTION EXTENDING FROM NEAR PILOT MOUND MB TO RUGBY AND WEST OF BIS. BASED ON CURRENT TIMING ADJUSTED POPS DELAYING HIGHER POPS ACROSS NW AND KEEPING SOUTHERN FA DRY LONGER. NO OTHER CHANGES THIS UPDATE. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 303 PM CDT SUN JUL 21 2013 MAIN CHALLENGE CONTINUES TO BE TSTM CHANCES AND SEVERITY FOR TONIGHT. LATEST MODEL GUIDANCE CONTINUES TO SUPPORT A THREAT FOR PORTIONS OF THE FA BUT EARLY ON MAINLY FOR THE KDVL REGION AS IT SHOULD TAKE A WHILE TO REACH THE RED RIVER VALLEY. CURRENTLY HAVE A COLD FRONT WORKING INTO FAR NORTHWEST ND WITH AN AREA OF LOW PRESSURE THERE AS WELL. A WARM FRONT EXTENDS SE FROM THIS LOW DOWN TO NEAR KBIS AND KABR. IN THIS WARM SECTOR DEW POINTS ARE GENERALLY IN THE LOW TO MID 60S WITH TEMPS IN THE 80S. EAST OF THE WARM FRONT DEW POINTS HAVE BEEN SLOW TO RECOVER FROM MORNING LOWS WITH 50S STILL COMMON. THERE HAS BEEN A WEAK TSTM COMPLEX OVER SOUTHWEST MANITOBA RIDING AHEAD OF THE MAIN SHORT WAVE. THIS SHOULD GET INTO THE FAR NW FA IN THE NEXT HOUR OR SO. INSTABILITY IS WEAK OUT AHEAD OF THIS INITIAL COMPLEX BUT IT MAY CONTINUE TO MOVE EAST ALONG THE BORDER WITH THE UPPER JET DYNAMICS IN PLACE. THE SEVERE THREAT SHOULD BE BEHIND THIS COMPLEX CLOSER TO THE COLD FRONT AND SFC LOW OVER WESTERN ND. INSTABILITY IS BETTER HERE WITH THE ABOVE MENTIONED WARMER AND MOIST AIR. THE MAIN SHORT WAVE ENERGY APPEARS TO BE LOCATED OVER SOUTHERN ALBERTA WHICH IS NEARING THE SFC BOUNDARY. WITH THE WAVE AND THE UPPER JET ENERGY A MORE ORGANIZED TSTM COMPLEX IS EXPECTED TO GET UNDERWAY OUT WEST. SPC HAS ISSUED MCD 1456 AND A NEW TORNADO WATCH FOR PORTIONS OF WESTERN AND CENTRAL ND. THERE HAVE BEEN A COUPLE OF CELLS THAT HAVE POPPED UP NEAR KISN THAT MAY BE THE START OF SOME STRONGER CELLS. NOT EXPECTING ANY STRONG STORMS TO APPROACH OUR WESTERN FA FOR A FEW MORE HOURS YET SO WE WILL HAVE TIME TO WATCH AND SEE HOW THINGS DEVELOP. LATEST RAP BRINGS SOME STORMS INTO OUR WESTERN FA IN THE 01-02Z MON TIME FRAME. NSSL WRF IS A LITTLE FASTER AND AS MENTIONED IN AN EARLIER AFD UPDATE IT DID BRING TSTMS A LOT FURTHER SOUTH THAN WHAT IS ANTICIPATED. FOLLOWED MORE CONTINUITY AND KEPT HIGHER PCPN CHANCES ACROSS THE NORTHERN HALF OF THE FA TONIGHT WITH LOWER CHANCES ACROSS THE SOUTH. THE COMBINATION OF THE LOW LEVEL JET UPPER JET AND THE WAVE SHOULD KEEP SHOWERS AND TSTMS GOING AFTER DARK JUST NOT SURE HOW LONG THE SEVERE POTENTIAL WILL GO. LEFT SOME LINGERING LOW PCPN CHANCES ACROSS THE EAST ON MONDAY MORNING WITH DRYING ACROSS THE WEST. SHOULD BE A FAIRLY NICE DAY WITH DRIER AIR MOVING BACK IN WITH NORTHWEST WINDS. MON NIGHT WILL BE A LITTLE COOL AGAIN ESPECIALLY ACROSS THE NORTH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 303 PM CDT SUN JUL 21 2013 SHOULD REMAIN DRY TUE WITH FAIRLY LIGHT WINDS DUE TO THE PROXIMITY OF THE SFC HIGH. CHANCES FOR PCPN RETURN BY TUE NIGHT AND WED ALTHOUGH MODELS NOT IN VERY GOOD AGREEMENT ON THE DETAILS. WEDNESDAY NIGHT-SUNDAY...12Z MODELS MAINTAIN SIMILAR IDEA AS PREVIOUS RUNS. NORTHWEST FLOW ALOFT INTO FRIDAY WITH UPPER RIDGING BUILDING INTO THE REGION FOR THE WEEKEND. THERE WILL BE SLIGHT THUNDERSTORM CHANCES WITH ANY UPPER WAVE WITHIN THE NORTHWEST FLOW ALOFT...WITH THESE CHANCES ENDING ONCE THE RIDGING BUILDS INTO THE REGION. TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL VALUES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 633 PM CDT SUN JUL 21 2013 STORMS WILL TAKE A LITTLE LONGER GETTING INTO FA BASED ON CURRENT CELL SPEED. MADE SOME MINOR ADJUSTMENTS TO TIMING HOWEVER KEPT VFR CONDITIONS GOING ALTHOUGH COULD SEE SOME MVFR CONDITIONS UNDER STRONGER STORMS. MAINTAINED DRY FORECAST FOR NOW AT FAR AND BJI. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...GODON LONG TERM...GODON/TG AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
638 PM CDT SUN JUL 21 2013 .UPDATE... ISSUED AT 633 PM CDT SUN JUL 21 2013 LINE OF DEEP CONVECTION EXTENDING FROM NEAR PILOT MOUND MB TO RUGBY AND WEST OF BIS. BASED ON CURRENT TIMING ADJUSTED POPS DELAYING HIGHER POPS ACROSS NW AND KEEPING SOUTHERN FA DRY LONGER. NO OTHER CHANGES THIS UPDATE. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 303 PM CDT SUN JUL 21 2013 MAIN CHALLENGE CONTINUES TO BE TSTM CHANCES AND SEVERITY FOR TONIGHT. LATEST MODEL GUIDANCE CONTINUES TO SUPPORT A THREAT FOR PORTIONS OF THE FA BUT EARLY ON MAINLY FOR THE KDVL REGION AS IT SHOULD TAKE A WHILE TO REACH THE RED RIVER VALLEY. CURRENTLY HAVE A COLD FRONT WORKING INTO FAR NORTHWEST ND WITH AN AREA OF LOW PRESSURE THERE AS WELL. A WARM FRONT EXTENDS SE FROM THIS LOW DOWN TO NEAR KBIS AND KABR. IN THIS WARM SECTOR DEW POINTS ARE GENERALLY IN THE LOW TO MID 60S WITH TEMPS IN THE 80S. EAST OF THE WARM FRONT DEW POINTS HAVE BEEN SLOW TO RECOVER FROM MORNING LOWS WITH 50S STILL COMMON. THERE HAS BEEN A WEAK TSTM COMPLEX OVER SOUTHWEST MANITOBA RIDING AHEAD OF THE MAIN SHORT WAVE. THIS SHOULD GET INTO THE FAR NW FA IN THE NEXT HOUR OR SO. INSTABILITY IS WEAK OUT AHEAD OF THIS INITIAL COMPLEX BUT IT MAY CONTINUE TO MOVE EAST ALONG THE BORDER WITH THE UPPER JET DYNAMICS IN PLACE. THE SEVERE THREAT SHOULD BE BEHIND THIS COMPLEX CLOSER TO THE COLD FRONT AND SFC LOW OVER WESTERN ND. INSTABILITY IS BETTER HERE WITH THE ABOVE MENTIONED WARMER AND MOIST AIR. THE MAIN SHORT WAVE ENERGY APPEARS TO BE LOCATED OVER SOUTHERN ALBERTA WHICH IS NEARING THE SFC BOUNDARY. WITH THE WAVE AND THE UPPER JET ENERGY A MORE ORGANIZED TSTM COMPLEX IS EXPECTED TO GET UNDERWAY OUT WEST. SPC HAS ISSUED MCD 1456 AND A NEW TORNADO WATCH FOR PORTIONS OF WESTERN AND CENTRAL ND. THERE HAVE BEEN A COUPLE OF CELLS THAT HAVE POPPED UP NEAR KISN THAT MAY BE THE START OF SOME STRONGER CELLS. NOT EXPECTING ANY STRONG STORMS TO APPROACH OUR WESTERN FA FOR A FEW MORE HOURS YET SO WE WILL HAVE TIME TO WATCH AND SEE HOW THINGS DEVELOP. LATEST RAP BRINGS SOME STORMS INTO OUR WESTERN FA IN THE 01-02Z MON TIME FRAME. NSSL WRF IS A LITTLE FASTER AND AS MENTIONED IN AN EARLIER AFD UPDATE IT DID BRING TSTMS A LOT FURTHER SOUTH THAN WHAT IS ANTICIPATED. FOLLOWED MORE CONTINUITY AND KEPT HIGHER PCPN CHANCES ACROSS THE NORTHERN HALF OF THE FA TONIGHT WITH LOWER CHANCES ACROSS THE SOUTH. THE COMBINATION OF THE LOW LEVEL JET UPPER JET AND THE WAVE SHOULD KEEP SHOWERS AND TSTMS GOING AFTER DARK JUST NOT SURE HOW LONG THE SEVERE POTENTIAL WILL GO. LEFT SOME LINGERING LOW PCPN CHANCES ACROSS THE EAST ON MONDAY MORNING WITH DRYING ACROSS THE WEST. SHOULD BE A FAIRLY NICE DAY WITH DRIER AIR MOVING BACK IN WITH NORTHWEST WINDS. MON NIGHT WILL BE A LITTLE COOL AGAIN ESPECIALLY ACROSS THE NORTH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 303 PM CDT SUN JUL 21 2013 SHOULD REMAIN DRY TUE WITH FAIRLY LIGHT WINDS DUE TO THE PROXIMITY OF THE SFC HIGH. CHANCES FOR PCPN RETURN BY TUE NIGHT AND WED ALTHOUGH MODELS NOT IN VERY GOOD AGREEMENT ON THE DETAILS. WEDNESDAY NIGHT-SUNDAY...12Z MODELS MAINTAIN SIMILAR IDEA AS PREVIOUS RUNS. NORTHWEST FLOW ALOFT INTO FRIDAY WITH UPPER RIDGING BUILDING INTO THE REGION FOR THE WEEKEND. THERE WILL BE SLIGHT THUNDERSTORM CHANCES WITH ANY UPPER WAVE WITHIN THE NORTHWEST FLOW ALOFT...WITH THESE CHANCES ENDING ONCE THE RIDGING BUILDS INTO THE REGION. TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL VALUES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 633 PM CDT SUN JUL 21 2013 STORMS WILL TAKE A LITTLE LONGER GETTING INTO FA BASED ON CURRENT CELL SPEED. MADE SOME MINOR ADJUSTMENTS TO TIMING HOWEVER KEPT VFR CONDITIONS GOING ALTHOUGH COULD SEE SOME MVFR CONDITIONS UNDER STRONGER STORMS. MAINTAINED DRY FORECAST FOR NOW AT FAR AND BJI. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...GODON LONG TERM...GODON/TG AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
559 PM CDT SAT JUL 20 2013 .UPDATE... ISSUED AT 559 PM CDT SAT JUL 20 2013 REGIONAL RADAR IMAGERY SHOWS A COUPLE OF AREAS TO WATCH THIS EVENING. FIRST IS IN OUR SOUTHWEST...WITH A SEVERE THUNDERSTORM WATCH BOX UP TO OUR SOUTHWEST BORDER FROM SOUTH DAKOTA. THUNDERSTORMS CONTINUE TO REMAIN SOUTH OF THE BORDER...BUT COULD DEVELOP A BIT FURTHER NORTH WITH AN AGITATED CUMULUS FIELD EVIDENT NEAR BAKER AND ALONG OUR FAR SOUTHWESTERN ZONES. THE OTHER AREA WAS SEEN OVER NORTHEASTERN MONTANA WITH SEVERE THUNDERSTORMS ROLLING OUT OF SOUTHERN SASKATCHEWAN AND INTO NORTHERN MONTANA. WILL CONTINUE TO MONITOR DEVELOPMENT OF THESE THUNDERSTORMS FURTHER EAST THIS EVENING AND OVERNIGHT...AS WHAT IS BEING INDICATED BY THE HRRR (HIGH RESOLUTION RAPID REFRESH MODEL)...AS WELL AS THE OTHER SHORT TERM MODELS. WARM AIR ADVECTION INCREASES OVERNIGHT AS NAM/GFS SOUNDINGS SHOW MODERATE VEERING WIND PROFILES FROM THE SFC TO 750MB. EXPECTING AN INCREASE IN THE AREAL COVERAGE OF SHOWERS/ELEVATED THUNDERSTORMS THROUGH EARLY SUNDAY MORNING...AS THEY CONTINUE TO DEVELOP ALONG A WARM FRONT IN EASTERN MONTANA. NAM/GFS SOUNDINGS SHOW DECENT INSTABILITY/CAPE ABOVE 750MB OVERNIGHT...WITH SHOWALTER INDICES SHOWING AN INCREASED POTENTIAL FOR ELEVATED THUNDERSTORMS WEST OF MINOT THROUGH 12Z SUNDAY. THUS WILL CONTINUE TO MENTION ISOLATED TO SCATTERED THUNDERSTORMS WEST...AND JUST INTO PORTIONS OF CENTRAL NORTH DAKOTA OVERNIGHT. WILL MONITOR FOR ANY SEVERE POTENTIAL DURING THE EVENING/OVERNIGHT. MOST OF WESTERN AND CENTRAL NORTH DAKOTA GET INTO THE WARM SECTOR BY LATE MORNING AND EARLY AFTERNOON SUNDAY...SETTING THE STAGE FOR SEVERE THUNDERSTORMS ALONG AND AHEAD OF AN ADVANCING COLD FRONT. SEE PREVIOUS DISCUSSION BELOW FOR MORE DETAILS. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 310 PM CDT SAT JUL 20 2013 MAIN CONCERNS THIS PERIOD WILL BE THUNDERSTORMS ASSOCIATED WITH A WARM FRONT EXTENDED ACROSS EASTERN MONTANA THAT IS FORECAST TO TRACK EAST ACROSS THE STATE LATE TONIGHT AND SUNDAY. SATELLITE LOOPS SHOW CLOUD COVER ACROSS WESTERN NORTH DAKOTA IN LOW LEVEL MOIST UP SLOPE FLOW. A BAND OF MID LEVEL SHOWERS AND ISOLATED THUNDERSTORMS IS MOVING THROUGH SOUTH CENTRAL NORTH DAKOTA. THIS IS EXPECTED TO DIMINISH AS IT MOVES EAST. THE FOCUS FOR TONIGHT AND SUNDAY WILL BE THE WARM FRONT IN EASTERN MONTANA THIS WILL BE PROVIDE LIFT AND WITH A SHORT WAVE TROUGH SUPPORT THUNDERSTORMS ACROSS THE NORTHWEST...AND THEN THE NORTH CENTRAL ON SUNDAY. ADDED THE MENTION OF SEVERE WHERE SPC HAS DEFINED THE SLIGHT RISK SUNDAY AFTERNOON. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 315 PM CDT SAT JUL 20 2013 THE RISK OF SEVERE WEATHER CONTINUES FROM SUNDAY AFTERNOON INTO THE NIGHT...MAINLY OVER THE CENTRAL AND EASTERN PARTS OF THE FORECAST AREA. LONG TERM MODELS ARE IN AGREEMENT THROUGH THE PERIOD ON THE BIG PICTURE...NAMELY THAT THE H5 RIDGE OFF THE SOUTHWEST COAST BUILDS EAST INTO THE DESERT SOUTHWEST AND EXPENDS NORTH INTO THE NORTHERN ROCKIES AND AMPLIFIES. THIS KEEPS A WEAK NORTHWEST FLOW OVER NORTH DAKOTA WITH CHANCES FOR THUNDERSTORMS COMING AS RIDGE RIDER SHORT WAVES CREST THE RIDGE AND PASS THROUGH EVERY OTHER DAY. THIS PATTERN IS ENHANCED AS AN H5 LOW CUTS OFF OVER ONTARIO AND SENDS A TROUGH AXIS THROUGH DURING THE THURSDAY-FRIDAY TIME FRAME. THAT...AS INDICATED IN THE PREVIOUS LONG TERM DISCUSSION...WILL BE THE GREATEST CHANCES FOR STORMS IN THE LONG TERM...AFTER SUNDAY NIGHT. BUT AGAIN...THERE ARE CHANCES ABOUT EVERY DAY AS TIMING OF THE WAVES WILL LIKELY CHANGE FROM FORECAST TO FORECAST. TEMPERATURES SHOULD BE FAIRLY STEADY IN THE PATTERN...AND NOT TOO FAR FROM NORMAL...GENERALLY IN THE MID 70S NORTHEAST TO MID 80S SOUTHWEST AND LOWS IN THE 50S TO LOWER 60S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 559 PM CDT SAT JUL 20 2013 LATEST SATELLITE AND RADAR IMAGERY SHOWS SCT/BKN VFR CIGS WITH DRY CONDITIONS AT THE AERODROMES. AN AREA OF SHOWERS AND THUNDERSTORMS IN NORTHEASTERN MONTANA WILL BEGIN TO SHIFT EAST OVERNIGHT...PRODUCING A MENTION FOR PREDOMINANT SHOWERS AND A VCTS AT KMOT/KBIS BY 09Z SUNDAY. ALTHOUGH VFR CIGS/VSBYS ARE ANTICIPATED NEXT 24HR...ANY OF THE STRONGER SHOWERS OR THUNDERSTORMS MAY RESULT IN BRIEF PERIODS OF MVFR/LOW VFR CIGS/VSBYS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...WAA LONG TERM...JPM AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
110 AM CDT SAT JUL 20 2013 .UPDATE... ISSUED AT 109 AM CDT SAT JUL 20 2013 OVERALL THE INHERITED FORECAST IS ON TRACK AND BLENDED TO THE 06 UTC OBSERVATIONS...WITH THE 04 UTC HRRR WEIGHTED HEAVILY FOR POPS FOR THE REMAINDER OF THE NIGHT GIVEN ITS GOOD HANDLING OF CONVECTIVE COVERAGE AND EVOLUTION THE PAST FEW HOURS. UPDATE ISSUED AT 903 PM CDT FRI JUL 19 2013 LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED THUNDERSTORMS STRETCHED FROM NORTHWEST TO SOUTHEAST ALONG AND AHEAD OF A COLD FRONT. BASED ON THE 3HR PRESSURE CHANGE...THIS FRONT WOULD ROUGHLY FOLLOW ALONG A WATFORD CITY TO HAZEN...AND INTO STEELE AND EDGELEY. SEVERAL OUTFLOWS EVIDENT WHICH MAY PRODUCE MORE CONVECTION ACROSS SOUTH CENTRAL NORTH DAKOTA THROUGH THE EVENING AND OVERNIGHT...WHICH IS WHAT THE HRRR INDICATES AS WELL. SEVERE THREAT LOOKS TO REMAIN ISOLATED BUT WILL NEED TO CLOSELY MONITOR. UPDATE ISSUED AT 659 PM CDT FRI JUL 19 2013 LATEST 3HR PRESSURE CHANGE SHOWS A COLD FRONT NEAR/ALONG OUR NORTHERN BORDER SLOWLY PUSHING SOUTH. SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP ALONG AND AHEAD OF THE FRONT AS THEY MOVE SOUTHEAST WITH TIME. LATEST HRRR/HIGH RESOLUTION RAPID REFRESH MODEL SHOWS FIRST AREA OF SHOWERS AND THUNDERSTORMS IN NORTH CENTRAL NORTH DAKOTA MOVING INTO THE JAMES RIVER VALLEY THROUGH 05Z SATURDAY. THE OTHER ITEM OF INTEREST ARE THE SHOWERS AND THUNDERSTORMS IN NORTHEAST MONTANA WHICH ARE FORECAST TO REACH KBIS BY AROUND 07Z. EXPECTING ISOLATED SEVERE THUNDERSTORMS TO CONTINUE THROUGH THE EVENING. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 306 PM CDT FRI JUL 19 2013 SHORT TERM CONCERNS INVOLVE THUNDERSTORMS NORTH CENTRAL ASSOCIATED WITH A CANADIAN COLD FRONT SLIDING SOUTH ACROSS THE REGION. CAPE VALUES SHOW POTENTIAL FOR STRONG THUNDERSTORMS BUT MID LEVEL LAPSE RATES AROUND 5 TO 6 DEGREES SHOULD LIMIT THE SEVERE POTENTIAL. HOWEVER THE POTENTIAL FOR SOME HAIL AND GUSTY WINDS EXISTS THIS EVENING. EXPECT SOME DIURNAL MINIMUM TONIGHT FOR THE STORMS...AND SCATTERED THUNDERSTORMS ALONG THE FRONTAL ZONE SOUTH CENTRAL AND WEST SATURDAY. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 306 PM CDT FRI JUL 19 2013 H5 PATTERN PER GFS/ECMWF CONTINUES WITH MOSTLY A NORTHWEST FLOW ALOFT THROUGH THE PERIOD. PERIODIC UPPER DISTURBANCES IN COMBINATION WITH INSTABILITY AND DYNAMICAL PARAMETERS IN PLACE WILL ALLOW FOR A CHANCE OF SHOWERS AND/OR THUNDERSTORMS ALMOST EVERYDAY...WITH THE EXCEPTION OF MONDAY...WHERE A DRY DAY IS FORECAST. FOR SATURDAY NIGHT AND SUNDAY...MAIN HIGHLIGHT HERE IS A MORE SIGNIFICANT SHORTWAVE MOVING THROUGH SOUTHERN SASKATCHEWAN SUNDAY MORNING AND INTO SOUTHERN MANITOBA BY SUNDAY AFTERNOON. A SURFACE COLD FRONT WILL BE ASSOCIATED WITH THE SHORTWAVE ALOFT AS IT SLIDES FROM WEST TO EAST SUNDAY AFTERNOON AND EVENING. BEST FORCING/OMEGA RESIDES IN THE NORTH CENTRAL SUNDAY AFTERNOON THEN SHIFTS INTO EAST CENTRAL NORTH DAKOTA SUNDAY EVENING. VERTICAL MOTION IS ENHANCED BY THE LEFT EXIT REGION OF A 60KT H3 JET STREAK ACROSS THE AFOREMENTIONED AREA. GFS SHOWS ENOUGH CAPE AND 0-6KM SHEAR OF 45KT TO 50KT FOR ORGANIZED STORMS WHICH WILL FAVOR SOME SEVERE THUNDERSTORMS NORTH CENTRAL THROUGH EAST CENTRAL SUNDAY AFTERNOON THROUGH SUNDAY EVENING. SPC DAY 3 OUTLOOK HAS THE ABOVE AREA IN A SEE TEXT WITH HAIL AND WIND AS THE PRIMARY THREATS. H85 TEMPS RISE TO BETWEEN +26C TO +28C IN THE WARM SECTOR SUNDAY AFTERNOON WEST PER NAM/GFS...HIGHS WILL TOP OUT AROUND 90 OR LOWER 90S. HAVE INCREASED TEMPS TO REFLECT THIS...HOWEVER DID NOT GO AS WARM AS THE NAM MOS WANTED DUE TO SOME CLOUD COVER HOLDING TEMPS BACK IN THE MORNING TO EARLY AFTERNOON. SHOULD BE A QUICK RISE THEREAFTER. MONDAY...BEHIND THE COLD FRONT...GFS SOUNDINGS SHOW LOW LEVEL COLD AIR ADVECTION WITH NEUTRAL ADVECTION ALOFT WILL YIELD A COOLER/DRIER DAY WITH HIGHS IN THE UPPER 70S NORTH TO UPPER 80S SOUTH. FOR TUESDAY THROUGH FRIDAY...ADDITIONAL SHORTWAVES EMBEDDED IN THE NORTHWEST FLOW WILL INTERACT WITH THE AFTERNOON/EVENING INSTABILITY AND SOME JET FORCING AT TIMES TO INITIATE A CHANCE OF SHOWERS/THUNDERSTORMS. .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 109 AM CDT SAT JUL 20 2013 OUTSIDE OF THUNDERSTORMS TONIGHT...VFR CONDITIONS ARE FORECAST FOR THE 06 UTC TAF CYCLE. ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE AT KISN...KDIK...KMOT AND KBIS THROUGH THE OVERNIGHT AND CODED AS VCTS FOR NOW AND WILL AMEND BASED ON RADAR TRENDS. .BIS WATCHES/WARNINGS/ADVISORIES... NONE. $$ UPDATE...AYD SHORT TERM...WAA LONG TERM...KS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
433 AM EDT SAT JUL 20 2013 .SYNOPSIS... A WEAK SHORTWAVE ALOFT WILL COMBINE WITH DIURNAL HEATING AND ABUNDANT MOISTURE FOR AFTERNOON AND EVENING CONVECTION. A COLD FRONT WILL PUSH SOUTHEAST INTO SOUTHERN WEST VIRGINIA SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... CODED CATEGORICAL POPS WITH THE INCOMING H5 VORTICITY MAXIMUM ASSOCIATED WITH BROAD LOW PRESSURE SYSTEM WAY NORTH IN CANADA. LOBES OF VORTICITY AT H5 WILL RIDE AROUND THE PERIPHERY TODAY PROVIDING SOME DYNAMIC LIFT. PWATS WILL INCREASE FROM 1.5 TO 2 INCHES BY THIS EVENING ACROSS THE LOWLANDS. THIS SHORTWAVE SEEMS TO DIMINISH IN INTENSITY OR SLOWS DOWN ACROSS NORTHERN HALF OF WV. THIS SCENARIO COULD PRODUCE HEAVY DOWNPOURS CAPABLE TO PRODUCE FLASH FLOODING. THEREFORE...ISSUED A FLASH FLOOD WATCH FOR THE NORTHERN HALF OF THE AREA THROUGH SUNDAY AFTERNOON. THE FOCUS OF THE CONVECTION IS EXPECTED EARLY TONIGHT ACROSS CENTRAL WV...THEN SLOWLY MOVE SOUTH AND EAST TO AFFECT THE SOUTHERN PORTIONS. THERE ARE SOME UNCERTAINTY WHERE THE BOUNDARY WILL STALL ATTM. THERE IS A SLIGHT RISK OF SEVERE WEATHER AT BOTH SIDES OF THE OH RIVER...INCLUDING NORTH CENTRAL WEST VIRGINIA. WENT WITH TEMPERATURES CLOSER TO THE BIAS CORRECTED MET GUIDANCE THROUGH THE PERIOD. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... MODELS AGREE THE FRONT WILL BE STALLED ACROSS THE CENTRAL OR NORTHERN PORTIONS OF THE AREA SUNDAY...THEN SLOWLY LIFT BACK NORTH SUNDAY NIGHT INTO MONDAY...AND FINALLY BE WELL NORTH OF THE AREA BY MONDAY NIGHT. OUR AREA WILL ALSO BE ON THE SOUTHERN EDGE OF THE WESTERLIES ALOFT. EMBEDDED SHORT WAVES MOVING OVER THE WARM AND SOUPY AIRMASS WILL CONTINUE A HIGH THREAT FOR SHOWERS AND THUNDERSTORMS RIGHT THROUGH TUESDAY. IN THIS PATTERN...TRACKING AND TIMING OF THESE SHORT WAVES WILL BE DIFFICULT TO EXACTLY DETERMINE THE CONVECTION SCENARIO. SO...WILL CONCENTRATE CONVECTION SUNDAY AND SUNDAY NIGHT IN THE CENTRAL AND SOUTH JUST AHEAD OF THE FRONT...SHIFTING INTO NORTHERN AREAS MONDAY AS THE FRONT LIFTS BACK NORTH. ON TUESDAY...WILL COAT A HIGH CHANCE EVERYWHERE...EVEN WITH THE FRONT NORTH OF THE AREA...AS THE MODELS DEPICT A FAIRLY STRONG AND MORE SYNOPTIC SCALE SHORT WAVE IN THE FLOW. EXCEPT FOR POSSIBLY THE NORTHERN AREAS SEEING A BRIEF DECREASE IN THE HEAT AND HUMIDITY SUNDAY...WE LOOK FOR THE WARMTH AND MUGGIES TO DOMINATE RIGHT THROUGH TUESDAY. SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE UNSETTLED WEATHER CONTINUES. NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN. TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE. HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF 2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS. ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER. BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES. OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT H5. ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND AFFECT MOST SITES AT THE END OF THE PERIODS.. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT. SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 07/20/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY L L L L L H H H H H H H HTS CONSISTENCY L L L L L L H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L L L L L L H H H H H H PKB CONSISTENCY L L L L L L H H H H H H CKB CONSISTENCY M M M M M M H H H H H H AFTER 06Z SUNDAY... IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS EACH MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH SUNDAY AFTERNOON FOR WVZ007>011-014>020-027>032-037>040-046-047. OH...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH SUNDAY AFTERNOON FOR OHZ066-067-075-076-083>086. KY...NONE. VA...NONE. && $$ SYNOPSIS...FB/JMV/MZ NEAR TERM...ARJ SHORT TERM...JMV LONG TERM...KTB AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
313 AM EDT SAT JUL 20 2013 .SYNOPSIS... UPPER HIGH PRESSURE DISSIPATING AS UPPER TROUGH APPROACHES GREAT LAKES. A COLD FRONT SAGS SLOWLY SOUTHWARD INTO THE AREA THIS WEEKEND...AND LIFTS BACK NORTH AS A WARM FRONT EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPDATED SKIES...POPS...AND WEATHER THROUGH SATURDAY PER LATEST MODEL RUNS...RADAR...AND SATELLITE IMAGES. REST OF FORECAST REMAINS REPRESENTATIVE. PREVIOUS DISCUSSION BELOW... STRATIFORM RAIN LEFT FROM THE CONVECTION TONIGHT. SHOULD DISSOLVE OUT OVER THE NEXT COUPLE OF HOURS. FOCUS THEN TURNS TO THE CONVECTION LATER TONIGHT. LOCAL MODELS BRING THE RENEWED ACTIVITY LATE TONIGHT INTO THE SOUTHEAST OHIO COUNTIES BY 12Z. THIS IS AHEAD OF THE LINE OF CONVECTION CURRENTLY WORKING THROUGH THE SOUTHERN GREAT LAKES AREA...ALTHOUGH IT COULD ALSO DEVELOP FROM THE VORT MAX TO THE WEST OVER SOUTHERN INDIANA. DIFFICULT TO TELL AT THIS TIME WHAT THE EXACT SOURCE WILL BE. PREVIOUS DISCUSSION... SCATTERED CONVECTION ONGOING ACROSS ENTIRE CWA. APPEARS TO BE JUST AHEAD OF VORT MAX IN EASTERN KY PER WATER VAPOR IMAGERY. EXPECT VORT MAX TO MOVE ACROSS LATE THIS AFTERNOON AND EVENING...AND SHOULD SEE DECREASING CONVECTION AS WE HEAD AFTER SUNSET WITH LOSS OF HEATING AND VORT MAX MOVING OUT TO THE NORTHEAST. ELONGATED LINEAR VORT MAX...WELL AHEAD OF THE COLD FRONT...WILL MOVE INTO FORECAST AREA FROM NW TOMORROW. ENTERING NW CWA 12Z-15Z AND THEN RUNNING FROM ABOUT HTS-EKN BY END OF NEAR TERM AT 00Z SUN. TIED LIKELY POPS TO THIS TIME/AREA TREND AS WELL. ALSO INCLUDED HEAVY RAIN MENTION WITH LIKELY POPS. THINK WE WILL BE ON THE SOUTHERN FRINGE OF ANY ORGANIZED SEVERE THREAT. BEST CHANCE FOR ANY ORGANIZED SEVERE WEATHER WOULD BE A COMPLEX THAT FORMS ALONG THE FRONT TO OUR NW AND THEN ARRIVES INTO OUR SE OHIO COUNTIES IN THE EVENING WITH DAMAGING WINDS THE MOST LIKELY THREAT. HOWEVER AS HEIGHTS AND FREEZING LEVELS DROP A BIT...LOCAL DOWNPOURS...GUSTY WINDS AND SMALL HAIL POSSIBLE IN ANY STRONGER CELLS. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... MODELS AGREE THE FRONT WILL BE STALLED ACROSS THE CENTRAL OR NORTHERN PORTIONS OF THE AREA SUNDAY...THEN SLOWLY LIFT BACK NORTH SUNDAY NIGHT INTO MONDAY...AND FINALLY BE WELL NORTH OF THE AREA BY MONDAY NIGHT. OUR AREA WILL ALSO BE ON THE SOUTHERN EDGE OF THE WESTERLIES ALOFT. EMBEDDED SHORT WAVES MOVING OVER THE WARM AND SOUPY AIRMASS WILL CONTINUE A HIGH THREAT FOR SHOWERS AND THUNDERSTORMS RIGHT THROUGH TUESDAY. IN THIS PATTERN...TRACKING AND TIMING OF THESE SHORT WAVES WILL BE DIFFICULT TO EXACTLY DETERMINE THE CONVECTION SCENARIO. SO...WILL CONCENTRATE CONVECTION SUNDAY AND SUNDAY NIGHT IN THE CENTRAL AND SOUTH JUST AHEAD OF THE FRONT...SHIFTING INTO NORTHERN AREAS MONDAY AS THE FRONT LIFTS BACK NORTH. ON TUESDAY...WILL COAT A HIGH CHANCE EVERYWHERE...EVEN WITH THE FRONT NORTH OF THE AREA...AS THE MODELS DEPICT A FAIRLY STRONG AND MORE SYNOPTIC SCALE SHORT WAVE IN THE FLOW. EXCEPT FOR POSSIBLY THE NORTHERN AREAS SEEING A BRIEF DECREASE IN THE HEAT AND HUMIDITY SUNDAY...WE LOOK FOR THE WARMTH AND MUGGIES TO DOMINATE RIGHT THROUGH TUESDAY. SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE UNSETTLED WEATHER CONTINUES. NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN. TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE. HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF 2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS. ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER. BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES. OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT H5. ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND AFFECT MOST SITES AT THE END OF THE PERIODS.. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT. SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 07/20/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY L L L L L H H H H H H H HTS CONSISTENCY L L L L L L H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L L L L L L H H H H H H PKB CONSISTENCY L L L L L L H H H H H H CKB CONSISTENCY M M M M M M H H H H H H AFTER 06Z SUNDAY... IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS EACH MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...FB/JMV/MZ NEAR TERM...MZ/26 SHORT TERM...JMV LONG TERM...KTB AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
158 AM EDT SAT JUL 20 2013 .SYNOPSIS... UPPER HIGH PRESSURE DISSIPATING AS UPPER TROUGH APPROACHES GREAT LAKES. A COLD FRONT SAGS SLOWLY SOUTHWARD INTO THE AREA THIS WEEKEND...AND LIFTS BACK NORTH AS A WARM FRONT EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... UPDATED SKIES...POPS...AND WEATHER THROUGH SATURDAY PER LATEST MODEL RUNS...RADAR...AND SATELLITE IMAGES. REST OF FORECAST REMAINS REPRESENTATIVE. PREVIOUS DISCUSSION BELOW... STRATIFORM RAIN LEFT FROM THE CONVECTION TONIGHT. SHOULD DISSOLVE OUT OVER THE NEXT COUPLE OF HOURS. FOCUS THEN TURNS TO THE CONVECTION LATER TONIGHT. LOCAL MODELS BRING THE RENEWED ACTIVITY LATE TONIGHT INTO THE SOUTHEAST OHIO COUNTIES BY 12Z. THIS IS AHEAD OF THE LINE OF CONVECTION CURRENTLY WORKING THROUGH THE SOUTHERN GREAT LAKES AREA...ALTHOUGH IT COULD ALSO DEVELOP FROM THE VORT MAX TO THE WEST OVER SOUTHERN INDIANA. DIFFICULT TO TELL AT THIS TIME WHAT THE EXACT SOURCE WILL BE. PREVIOUS DISCUSSION... SCATTERED CONVECTION ONGOING ACROSS ENTIRE CWA. APPEARS TO BE JUST AHEAD OF VORT MAX IN EASTERN KY PER WATER VAPOR IMAGERY. EXPECT VORT MAX TO MOVE ACROSS LATE THIS AFTERNOON AND EVENING...AND SHOULD SEE DECREASING CONVECTION AS WE HEAD AFTER SUNSET WITH LOSS OF HEATING AND VORT MAX MOVING OUT TO THE NORTHEAST. ELONGATED LINEAR VORT MAX...WELL AHEAD OF THE COLD FRONT...WILL MOVE INTO FORECAST AREA FROM NW TOMORROW. ENTERING NW CWA 12Z-15Z AND THEN RUNNING FROM ABOUT HTS-EKN BY END OF NEAR TERM AT 00Z SUN. TIED LIKELY POPS TO THIS TIME/AREA TREND AS WELL. ALSO INCLUDED HEAVY RAIN MENTION WITH LIKELY POPS. THINK WE WILL BE ON THE SOUTHERN FRINGE OF ANY ORGANIZED SEVERE THREAT. BEST CHANCE FOR ANY ORGANIZED SEVERE WEATHER WOULD BE A COMPLEX THAT FORMS ALONG THE FRONT TO OUR NW AND THEN ARRIVES INTO OUR SE OHIO COUNTIES IN THE EVENING WITH DAMAGING WINDS THE MOST LIKELY THREAT. HOWEVER AS HEIGHTS AND FREEZING LEVELS DROP A BIT...LOCAL DOWNPOURS...GUSTY WINDS AND SMALL HAIL POSSIBLE IN ANY STRONGER CELLS. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... BASING FORECAST ON SURFACE FRONT REACHING NEAR A MGW-PKB-UNI LINE BY 12Z SUNDAY...THEN STALLING OUT DURING THE DAY ON SUNDAY...BETWEEN THAT LINE AND THE HTS-CRW-EKN LINE. STILL SOME QUESTION HOW QUICKLY THE PRE FRONTAL CONVECTION SAGS SOUTH INTO NORTHEAST KENTUCKY TO SOUTHERN WEST VIRGINIA SATURDAY EVENING. TRIED TO SLOW THE SOUTHERN PROGRESS OF THE HIGHER POPS SOUTHWARD. PLENTY OF LOW CLOUDS SHOULD LINGER NORTH OF THE FRONT SUNDAY MORNING. THAT IN COMBINATION WITH THE HIGHER PROBABILITIES OF RAIN ACROSS THE SOUTHERN HALF OF THE CWA...KEPT MAXIMUM TEMPERATURES LOWER THAN MOS GUIDANCE. NEXT MID LEVEL DISTURBANCE MOVES UP THE OHIO VALLEY OVERNIGHT SUNDAY NIGHT...SO HAVE POPS INCREASING AND MOVING BACK NORTHEAST. THE AXIS OF THAT MID LEVEL TROF AT 700 TO 500 MB PASSES OVERNIGHT MONDAY NIGHT. SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM. && .LONG TERM /TUESDAY THROUGH FRIDAY/... WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE UNSETTLED WEATHER CONTINUES. NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN. TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE. HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7. && .AVIATION /05Z SATURDAY THROUGH WEDNESDAY/... STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF 2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS. ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER. BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES. OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT H5. ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND AFFECT MOST SITES AT THE END OF THE PERIODS.. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT. SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 07/20/13 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 CRW CONSISTENCY M L L L L L L M H H H H HTS CONSISTENCY L L L L L L L L H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L L L L L L L L H H H H PKB CONSISTENCY M L L L L L L L H H H H CKB CONSISTENCY M M M M M M M M H H H H AFTER 06Z SUNDAY... IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS EACH MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...FB/MZ NEAR TERM...MZ/26 SHORT TERM...KTB LONG TERM...KTB AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
915 AM EDT SAT JUL 20 2013 .SYNOPSIS... A HEAT WAVE-ENDING COLD FRONT MOVES THOUGH LATE TODAY... A MID-TROPOSPHERIC TROUGH WILL PUSH COOLER DRIER AIR INTO THE REGION OVER THE NEXT 24 HOURS. IT WILL ALSO TRIGGER SOME STRONG THUNDERSTORMS. A SECOND TROUGH AND ATTENDANT COLD FRONT COULD TRIGGER SHOWERS TOWARD MID-WEEK. OVERALL...AN UPPER LEVEL TROUGH WILL DOMINATE OUR AREA. THUS MOST OF NEXT WEEK WILL FEEL RELATIVELY COOL TO OUR RECENT HEAT WAVE. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... 13Z...EARLIER WIDESPREAD RAIN SHIELD TO THE NORTH HAS DISSIPATED. ONLY REMAINING SHOWERS ARE IN THE SW/SC MTS...BUT TAME AT THIS TIME. RUC HANDLING THE CURRENT COVERAGE OF THE SHOWERS WELL...AND OUTPUT HAS BEEN USED AS BASIS FOR REST OF THE POP GRIDS FOR TODAY. SEVERE STORMS STILL POSSIBLE...BUT WE WILL HAVE TO GET RID OF THE HIGHER CLOUDS. THIS SHOULD NOT BE A PROBLEM...AND BLYR MOISTURE IS GOING TO BE HIGH. DEWPOINTS ACTUALLY REMAIN HIGHER IN THE AREAS WHICH WERE DRY OVERNIGHT. REST AS FOLLOWS FROM PREV DISCS... 0820Z UPDATE...THE SERIES OF CONVECTIVE LINES AND THE MCS ACTIVITY TO OUR WEST TRIGGERED SOME SHOWERS IN WARREN COUNTY. THE LATEST ROUND OF INTENSE CONVECTION IS NOW IN NORTHERN OHIO. MOST HIGH RESOLUTION MODELS HAVE DIFFICULTY BRINGING THIS CONVECTION INTO OUR REGION WITH MUCH VIGOR. SHOWERS AND THUNDERSTORMS ARE LIKELY IN NORTHWESTERN AREAS THIS MORNING. THESE SEEM HIGH RESOLUTION MODELS IMPLY A BETTER CHANCE OF STRONG STORMS IN BOTH SOUTHWEST AND CENTRAL AREAS...GENERALLY AFTER ABOUT 2 PM TODAY. THE NCEP MODEL SUITE AND ENSEMBLES IMPLY A STRONG LOW- LEVEL JET...SOME GOOD CAPE OVER 1500JKG-1 AND STRONG SOUTHWESTERLY FLOW. THUS SOME MULTI-CELLULAR LINES COULD DEVELOP AND THIS WOULD LIKELY PRODUCE SOME POTENTIAL SEVERE STORMS LATER THIS AFTERNOON. MORE MODESTLY...OVERNIGHT TEMPERATURES ARE IN THE 70S NEARLY EVERYWHERE...EVEN IN THE NORTHWEST DUE TO CLOUDS AND ENHANCED SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT TO OUR NORTHWEST. DEW POINTS ARE IN THE 60S TO NEAR 70 IN THE EXTREME SOUTHEAST. THE TEMPERATURE AND HUMIDITY VALUES KEEP ALL PUT A FEW ISOLATED POINT APPARENT TEMPS BELOW 100...NO HEAT PRODUCTS TODAY. IT WILL STILL BE HOT IN EAST AS THE COLD FRONT WILL BE SLOWER TO ARRIVE. BEST CHANCE PRECIPITATION WILL BE BEFORE 19Z IN NORTHWEST AND AFTER ABOUT 20Z IN SOUTHERN AREAS. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/... THE COOLER AND DRIER AIR SHOULD TAKE HOLD OF THE NORTHERN TIER BY EARLY EVENING AND THE CHANCE OF PRECIPITATION WILL BE LOW. MOST CENTRAL AREAS TOO SHOULD BE NORTH OF THE MAIN AREA OF RAIN THREAT WITHIN A FEW HOURS OF 6 PM. THE SREF AND OTHER MODELS IMPLY LINGERING THREAT OF SHOWERS AND THUNDERSTORMS IN SOUTHERN AREAS AND ESPECIALLY SOUTHEAST LINGERS TO ABOUT 8-10 PM. THE WINDS BECOME WEST TO NORTHWEST OVER MOST OF THE REGION DURING THE EVENING HOURS...THE HIGH PW AIR IS GENERALLY CONFINED TO THE SOUTHEAST AFTER ABOUT 7 PM THIS EVENING AND BY ABOUT 8 AM SUNDAY THE PW VALUES ARE NORMAL ACROSS OUR ENTIRE REGION. THE FRONT WILL BE SLOW TO CLEAR THE SOUTH EASTERN MOST AREAS UNTIL EARLY SUNDAY MORNING. HAD TO HOLD SOME POPS IN ALONG SOUTHERN AREAS INTO EARLY SUNDAY. BEST NEWS IS THE 20C ISOTHERM AT 850 HPA IS GONE BEFORE 5 PM THIS EVENING AND WE KICK THE 18C ISOTHERM OUT BY ABOUT 7 PM. BETTER YET...WE WELCOME THE 12C ISOTHERM INTO THE STATE ABOUT 7 AM SUNDAY AND LET IT SAG SOUTH DURING THE DAY SUNDAY. IT SHOULD BE A SPECTACULARLY COMFORTABLE DAY SUNDAY. WITH LOW PW VALUES AND COOLER TEMPERATURES. HOPEFULLY ANY CONVECTION WILL BE CLOSE TO THE FRONT SOUTH OF THE MASON-DIXON LINE. WE CAN SAY GOOD BY TO THE HEAT WAVE OF MID JULY 2013. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... SUNDAY SHOULD BE A POST FRONTAL DAY WITH PW VALUES NEAR TO SLIGHTLY BELOW NORMAL. THE LOWER TROPOSPHERIC TEMPERATURES WILL BE NEAR NORMAL TOO. THE CHANCE FOR SHOWERS SHOULD BE LOW...WITH PERHAPS THE HIGHEST CHANCE IN THE SOUTHERNMOST AREAS...CLOSE TO THE FRONTAL BOUNDARY. OVERALL...SUNDAY IS LOOKING LIKE A VERY PLEASANT DAY FOR MOST AREAS AS A WEAK AREA OF HIGH PRESSURE WILL BE OVER THE REGION. THE LOWER HUMIDITY AND LOWER TEMPERATURES SHOULD BE WELCOME RELIEF. THE LOW-LEVEL FRONTAL BOUNDARY DOES NOT PUSH TOO FAR TO OUR SOUTH. ANOTHER WAVE APPROACHES FROM THE WEST AND WILL LIKELY PULL SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO TUESDAY. THIS WILL INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT...WHICH MAY LINGER INTO TUESDAY. NORTHWESTERLY FLOW WILL LIKELY PUSH A FRONT THROUGH THE REGION AROUND MID-WEEK. THIS COULD INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS...MOST LIKELY ON WEDNESDAY. BEHIND THIS SECOND FRONT THE PW VALUES DROP TO BELOW NORMAL...SHOULD BE VERY COMFORTABLE THURSDAY AND FRIDAY BEHIND THIS FRONT SHOULD THESE FORECAST PROVE CLOSE TO CORRECT. OVERALL...THE MODELS AND ENSEMBLES ALL SHOW A TROUGH OVER THE EASTERN USA MOST OF THE COMING WEEK IMPLYING COOLER AND RELATIVELY DRIER WEATHER. BY MID-WEEK THE HEAT WAVE OF MID-JULY 2013 SHOULD BE A FAINT MEMORY. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... A LINE OF CONVECTION CONTINUES TO MAKE ITS WAY THROUGH CENTRAL PA. IFR CIGS AND VSBYS HAVE REACHED BFD...JST AND AOO. SHOWERS AND THUNDERSTORMS WILL CONTINUE ALONG THE SOUTHERN HALF OF THE STATE THROUGH MID MORNING. ANY SHOWERS AND THUNDERSTORMS SHOULD FALL APART BY THEY REACH THE CENTRAL PART OF THE STATE AND SHOULD NOT AFFECT MDT AND LNS. ANY STORMS SHOULD CONTINUE TILL 14Z...BEFORE THEY FALL APART. EXPECT SHOWERS AND THUNDERSTORMS TO BE POSSIBLE THIS AFTERNOON OUT AHEAD OF THE INCOMING COLD FRONT. AS THE COLD FRONT CROSSES THE REGION LATE TODAY IT SHOULD TRIGGER SCT STRONG TO POSSIBLY SEVERE STORMS. THE WIND SHIFT SHOULD OCCUR FROM NW- SE BY SAT NIGHT. CLEARING SKIES WITH DRIER AIR SHOULD BUILD IN BEHIND THE FRONT...LATE TONIGHT INTO SUNDAY MORNING. OUTLOOK... SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH. MON...VFR. TUE-WED...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT/STEINBUGL NEAR TERM...GRUMM/DANGELO SHORT TERM...GRUMM LONG TERM...GRUMM/CERU AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
449 PM EDT SAT JUL 20 2013 .SYNOPSIS... HIGH PRESSURE OVER THE SOUTHEAST WILL WEAKEN OVER THE WEEKEND AS A COLD FRONT MOVES SOUTHWARD FROM THE GREAT LAKES. THE FRONT WILL STALL NORTH OF THE AREA ON SUNDAY AND THEN DISSIPATE OR RETURN NORTHWARD INTO MONDAY. AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE EAST ON TUESDAY AND LINGER THROUGH LATE WEEK. A SECOND WEAK COLD FRONT WILL ARRIVE FROM THE NORTHWEST ON THURSDAY AND SETTLE JUST SOUTHEAST OF THE REGION THROUGH FRIDAY. && .NEAR TERM /THROUGH SUNDAY/... 400 PM UPDATE...STORMS EXTEND ACRS THE PIEDMONT ATTM...ALIGNED ALONG MERGED GUST FRONT. SEEMS THERE IS JUST ENOUGH WLY UNIDIRECTIONAL FLOW TO ALLOW THE STORMS TO ORGANIZE IN THIS WAY. WHILE THE LINE IS ADVANCING SLOWLY INTO 3000 J/KG SBCAPE IT APPEARS THE GUST FRONT IS OUTRUNNING IT. DOWNWARD TREND NOTED IN LIGHTNING FREQUENCY WITH STORMS NEAR NC/SC BORDER. SO THE LINE MAY NOT PERSIST TOO MUCH LONGER. THIS WOULD AGREE WITH LATEST HRRR ALSO. HOWEVER ISOLATED CELLS ARE FORMING OVER CHARLOTTE METRO AND THE GUST FRONT MAY KICK OFF SOME NEW ACTION OVER THE SC PIEDMONT. THUS AMPED UP POPS AHEAD OF THE LINE DESPITE ITS WEAKENING...MAINTAINING CHANCE POPS N AND W WHERE REDEVELOPMENT QUITE POSSIBLE. TRIED TO ADJUST TEMP TRENDS WHICH HAVE BEEN AFFECTED BY THE COOL OUTFLOW...BUT THIS IS DIFFICULT SO HAVE LOW CONFIDENCE IN TEMP FCST THRU EARLY EVENING. AT 230 PM EDT SATURDAY...AN UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY OVER THE EASTERN USA TONIGHT AND SUNDAY. A SHORTWAVE WILL MOVE INTO THE BASE OF THIS TROUGH OVER THE TN RIVER VALLEY LATE SUNDAY. DEEP GULF MOISTURE WILL BE TRANSPORTED NORTH INTO OUR AREA BY A GENTLE SW LOW LEVEL FLOW ON THE WEST SIDE OF A BERMUDA HIGH...WHILE A COLD FRONT DROPS SOUTH INTO VA. WITH LOW LEVEL FLOW NEARLY PARALLEL THE TO THE BLUE RIDGE...UPSLOPE FLOW WILL BE LIMITED...THOUGH STILL PRESENT. WITH THE LOWE LEVELS STABILIZING LATE THIS EVENING... CONVECTIVE COVER SHOULD DIMINISH. MODEL SOUNDINGS SHOW CAPE SURPASSING 1000 J/KG AGAIN ON SUNDAY...AND CONVECTIVE TRENDS ARE EXPECTED TO MIMIC TODAY...WITH THE GREATEST COVERAGE IN THE MOUNTAINS...WITH ACTIVITY SPREADING EAST INTO THE FOOTHILLS AND PIEDMONT WITH TIME. SHEAR WILL REMAIN WEAK HOWEVER...LIMITING STORM ORGANIZATION. MINIMUM TEMPERATURES WILL BE SEVERAL DEGREES ABOVE NORMAL TONIGHT IN A MOIST AIR MASS. MAXIMUM TEMPERATURES SUNDAY WILL BE SLIGHTLY BELOW NORMAL...WITH CLOUDS...MOISTURE A FALLING HEIGHTS ALOFT LIMITING WARMING. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... AT 230 PM SATURDAY... 500 MB HEIGHTS GRADUALLY LOWER OVER THE SOUTHEAST MONDAY AND TUESDAY BUT SURFACE PATTERN CHANGES WILL BE RATHER SUBTLE. DIURNAL CONVECTION WILL CONTINUE INTO THE FORECAST PERIOD BEGINNING 00Z MONDAY THEN GRADUALLY DIMINISH DURING THE NIGHT. MOIST AND MODERATELY UNSTABLE AIR MASS WILL CONTINUE OVER THE REGION AND GFS DEPICTS SHORT WAVE TROUGH APPROACHING CWA BY 12Z MONDAY... SO AT LEAST SLIGHT CHANCE POPS WILL CONTINUE WELL INTO THE NIGHT. DURING DAYTIME MONDAY... CWA REMAINS IN AIRMASS CONDUCIVE TO CONVECTIVE STORM DEVELOPMENT SO POPS WILL INCREASE WITH DAYTIME HEATING INTO CHANCE CATEGORY WITH LIKELY POPS OVER HIGHER TERRAIN. GFS HAS ANOTHER SHORT WAVE TROUGH DROPPING INTO LONG WAVE TROUGH POSITION EARLY TUESDAY... SO CHANCE POPS WILL CONTINUE THROUGH THE NIGHT AND INTO TUESDAY WHEN DIURNAL HEATING CYCLE ONCE AGAIN LEADS TO HIGHER PROBABILITIES DURING AFTERNOON. NO SIGNIFICANT TEMPERATURE CHANGES WILL OCCUR DURING MONDAY TUESDAY. HIGHS OUTSIDE THE MOUNTAINS WILL BE IN THE UPPER 80S AND LOWER 90S WHILE MOUNTAIN VALLEY TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 80S. VERY WARM LOW TEMPERATURES IN THE 60S AND LOWER 70S ARE EXPECTED TO CONTINUE. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 230 PM SATURDAY... FLOW PATTERN ACROSS U.S. DURING THE PERIOD WILL CONSIST OF RIDGE IN THE WEST AND TROUGH OVER THE EASTERN STATES. BOUNDARY LAYER WILL REMAIN WARM AND MOIST SO COOL TEMPERATURES ALOFT ON WEDNESDAY WILL SUPPORT LAPSE RATES SUFFICIENTLY STEEP TO PROMOTE CONVECTION WITH APPROACH AND PASSAGE EARLY THURSDAY OF COLD FRONT. THEREAFTER DETAILS BECOME DIFFICULT TO RESOLVE AS FRONT DRIFTS SLOWLY SOUTHEAST AND APPEARS IN CURRENT GUIDANCE TO BECOME NEARLY STATIONARY JUST AFTER CROSSING CWA. THUS... AIR MASS CHANGE WILL NOT BE SUFFICIENTLY SIGNIFICANT TO ELIMINATE POPS BUT NUMBERS WILL BE IN THE LOWER END OF THE CHANCE SPECTRUM AND WILL DISPLAY A DIURNAL TREND. NO SIGNIFICANT CHANGES IN TEMPERATURE EXPECTED. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... AT KCLT /21Z UPDATE/...A BLEND OF MAV AND MET GUIDANCE SUPPORTS MVFR FOG AT DAYBREAK SUNDAY. GUIDANCE WAS ALL OVER THE PLACE ON CIGS...SO A NEARLY PERSISTENCE FORECAST WAS USED...TAKING THE CIG DOWN TO THE LOW END OF MVFR BY DAYBREAK. THUNDERSTORM COVERAGE WARRANTS A MENTION IN THE TAF THIS AFTERNOON...WITH POSSIBLE MVFR VSBY AND CIG RESTRICTIONS. DIFFICULT TO TELL AT THIS POINT IF BEST TSTM CHANCES COME WITH THE LINE SLOWLY PROGRESSING INTO THE PIEDMONT OR FROM ISOLATED CELLS AHEAD OF IT. WILL EXTEND TEMPO A BIT LATER GIVEN CURRENT TRENDS. WINDS WILL REMAIN LIGHT FROM THE SW EXCEPT DURING TS OUTFLOW EFFECTS THIS AFTN...WHICH WILL MOST LIKELY CAUSE A BRIEF PERIOD OF NW GUSTS UP TO 20-25 KT. ELSEWHERE...MODEL GUIDANCE IS SUPPORTIVE OF DAYBREAK MVFR FOG SUNDAY MORNING AT ALL FOOTHILLS SITES EXCEPT KGMU...AND SUPPORTS IFR FOG AT KAVL. GUIDANCE VARIED WILDLY ON CIGS...SO A NEAR PERSISTENCE FORECAST WAS USED...TAKING FOOTHILL SITES DOWN TO LOW END MVFR..AND KAVL BACK DOWN TO LIFR. CONVECTIVE CHANCES SUPPORT CARRYING THUNDER IN THE TAFS THIS AFTERNOON. LIGHT WINDS WILL PERSIST FROM THE SW...EXCEPT AT KAVL WHERE THEY WILL VEER TO NW LATE TONIGHT. OUTLOOK...A COLD FRONT WILL SAG SEWD INTO THE AREA THIS WEEKEND. EXPECT ABOVE NORMAL TSRA COVERAGE SUNDAY AND INTO EARLY NEXT WEEK...WITH BEST CHANCES STILL DURING AFTERNOONS AND EVENINGS. CONFIDENCE TABLE... 20-02Z 02-08Z 08-14Z 14-20Z KCLT HIGH 100% HIGH 89% MED 69% HIGH 83% KGSP HIGH 100% HIGH 89% MED 66% HIGH 83% KAVL HIGH 100% HIGH 89% MED 64% MED 65% KHKY HIGH 100% HIGH 88% LOW 50% MED 67% KGMU HIGH 100% HIGH 89% MED 70% MED 67% KAND HIGH 98% HIGH 88% MED 70% HIGH 83% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...PAT NEAR TERM...JAT/WIMBERLEY SHORT TERM...LGL LONG TERM...LGL AVIATION...JAT/WIMBERLEY =
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
319 PM CDT SAT JUL 20 2013 .SHORT TERM...TONIGHT THROUGH MONDAY NIGHT SEVERAL WEAK SHORT WAVES EMBEDDED WITHIN THE NORTHWEST FLOW ALOFT WILL BRING ISOLATED TO SCATTERED THUNDERSTORMS ACROSS THE REGION THIS EVENING THOUGH SUNDAY. WITH HI-RES MODELS STRUGGLING TO DEPICT THE AREAS OF CONVECTION...WITH MAINTAIN AT LEAST A LOW POP THROUGH 18Z SUNDAY. AS OF 19Z...A NARROW LINE OF SHOWERS ARE MOVING SE ACROSS HYDE/HAND COUNTY. THESE STORMS SHOULD CONTINUE TO DISSIPATE AS THEY EXIT THIS CWA. FARTHER WEST...A MORE PRONOUNCED SHORT WAVE HAS CAUSED CONVECTION A DEVELOP OVER THE BLACK HILLS. THIS AREA IS BASICALLY UNCAPPED WITH SB-CAPE VALUES AROUND 2000 J/KG. THESE STORMS SHOULD CONTINUE TO GROW AS SOUTH TO EASTERLY LOW LEVEL FLOW WILL FILTER MOISTURE INTO SW SOUTH DAKOTA. WOULD EXPECT THESE STORM WILL REMAIN JUST SOUTH OF THE CWA AS THE LAYER STORM MOTION OFF THE RUC SUGGEST A SE MOTION. THAT SAID...SEVERAL OUTFLOW BOUNDARIES FROM EARLIER CONVECTION COULD RESULT IN A NORTHWARD JOG. CHANCES FOR THUNDERSTORMS IN THE EASTERN CWA TONIGHT/SUNDAY IS A LITTLE UNCLEAR AT THIS TIME. HALF THE MODEL SUGGEST LLJ INDUCED THUNDERSTORMS MOVING ACROSS THE EASTERN DAKOTAS BY 12Z. OTHERS SUGGEST CONVECTION COULD BE SOUTH/EAST/OR NORTH OF THIS CWA. WITH VERY LOW CONFIDENCE...WILL BROAD BRUSH MOST OF THE CWA WITH LOW POPS FOR NOW ON SUNDAY. AN AREA OF LOW PRESSURE AND SURFACE COLD FRONT WILL MOVE ACROSS THE REGION ON SUNDAY NIGHT/MONDAY MORNING. WITH THE MAJORITY OF THE PCPN FALLING POST FRONTAL...SEVERE STORMS DO NOT APPEAR POSSIBLE. COOLER TEMPERATURES ARE EXPECTED ON MONDAY WITH HIGHS IN THE UPPER 70S..IN THE NE...TO AROUND 90 IN THE SOUTHWEST CWA. A BLEND OF CONSALL/ALLBLEND SHOWS HIGHS COULD BE SLIGHTLY COOLER THAN CURRENTLY ADVERTISED. .LONG TERM...TUESDAY THROUGH SATURDAY NORTHWEST FLOW ALOFT WILL DOMINATE THROUGH THE EXTENDED. MAIN FORECAST CHALLENGE WILL BE TIMING SHORTWAVE ACTIVITY. THE PATTERN WILL REMAIN VERY ACTIVE THROUGH THURSDAY WITH A SERIES OF SHORTWAVES. TIMING AND INTENSITY ARE VERY DIFFICULT TO DETERMINE AT THIS TIME RANGE SO CONFIDENCE IN POPS IN ANY GIVEN PERIOD IS LOW. THAT SAID TUESDAY NIGHT DOES SEEM TO HAVE MODEL AGREEMENT ON BEING DRY WHILE THURSDAY HAS BEEN CONSISTENTLY STORMY. STUCK CLOSE TO ALLBLEND POPS BECAUSE OF UNCERTAINTY. BY FRIDAY SFC HIGH PRESSURE BEGINS TO DROP OUT OF CANADA AND NOSE INTO EASTERN SD. THE START OF THE WEEKEND APPEARS DRY FOR NOW AS A RESULT. TEMPERATURES WILL BE MUCH COOLER THROUGH THE PERIOD WITH HIGHS RANGING FROM THE UPPER 70S IN THE EAST TO THE MID 80S IN THE SOUTHWEST. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS WILL PREVAIL. ISOALTED SHOWERS AND TSTORMS ARE CONTINUING THIS AFTERNOON BUT HAVE MANAGED TO AVOID THE TAF SITES. STORMS MAY BECOME MORE WIDESPREAD IN THE WEST THIS EVENING SO LEFT IN THE VCTS MENTION AT KMBG/KPIR FOR AFTER 00Z. HI-RES MODELS INDICATE THE EAST MAY SEE AN ISOLATE STORM OR TWO THIS EVENING AS WELL BUT LOCATION AND TIMING ARE TOO DIFFICULT TO PINPOINT. MAY NEED TO ADD VCTS AT SOME POINT TO KATY/KABR BUT LEFT OUT FOR NOW. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...SD LONG TERM...WISE AVIATION...WISE WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1137 PM CDT FRI JUL 19 2013 .DISCUSSION... SEE THE 06Z AVIATION DISCUSSION BELOW. && .AVIATION... A FEW SHOWERS CONTINUE NEAR THE KJCT TERMINAL AND MAY CONTINUE FOR A FEW MORE HOURS OVERNIGHT IN AN AREA OF MODEST LARGE SCALE ASCENT AND WEAK LOW LEVEL WARM ADVECTION. THE DEVELOPMENT OF CLOUDS IN THE 6-10 KFT LAYER MAY PRECLUDE LOW CLOUDS OVERNIGHT BUT I DID NOT WANT TO REMOVE THEM JUST YET. WILL LET THE NEXT SHIFT MONITOR THE TRENDS OVERNIGHT. IF LOW CLOUDS DO FORM...THE ARE EXPECTED TO RANGE BETWEEN 1-2 KFT AT KJCT/KSOA AND COULD BRIEFLY AFFECT KSJT/KBBD AFTER SUNRISE AS THE STRATO CU BEGINS TO DEVELOP. OTHERWISE...EXPECT VFR CONDITIONS WITH A GENERALLY SOUTHERLY WIND AT 10 KTS OR LESS. JOHNSON && .PREV DISCUSSION... /ISSUED 938 PM CDT FRI JUL 19 2013/ UPDATE... ADDED ISOLATED SHOWERS OVER FAR SOUTHERN SECTIONS AND MADE MINOR TWEAKED TO DEWPOINTS AND SKY COVER FOR THE REST OF TONIGHT. DISCUSSION... LATEST NAM AND HRRR ARE INDICATING SOME LIGHT RAIN SHOWERS DEVELOPING ACROSS PORTIONS OF THE NORTHWEST HILL COUNTRY AND NORTH EDWARDS PLATEAU AFTER 03Z. THIS SEEMS TO BE TIED TO SOME ENHANCED LOW LEVEL MOISTURE ADVECTION AND WEAK CONVERGENCE ACROSS THIS AREA. ADDED ISOLATED RAIN SHOWERS ACROSS SOUTHERN COUNTIES FOR THE OVERNIGHT PERIOD AND TWEAKED DEWPOINTS AND SKY COVER TO ACCOUNT FOR TRENDS. UPDATED PRODUCTS HAVE BEEN SENT. PREV DISCUSSION... /ISSUED 620 PM CDT FRI JUL 19 2013/ DISCUSSION... SEE THE 00Z AVIATION DISCUSSION BELOW. AVIATION... A FEW DIURNAL SHOWERS HAVE DEVELOPED TO THE NORTH OF KABI AND SOUTHEAST OF KJCT BUT I EXPECT MOST OF THIS TO DISSIPATE WITHIN THE NEXT 1-2 HOURS AS WE LOSE DAYTIME HEATING. THE CU FIELD WILL HOLD ON FOR A FEW HOURS BUT SHOULD THIN OVERNIGHT. THERE IS SOME INDICATION IN THE NAM AND HRRR MODELS THAT NOCTURNAL SHOWERS COULD DEVELOP SOUTH OF A KSJT TO KBBD LINE TONIGHT BUT CONFIDENCE IS VERY LOW SO THE TAFS MAINTAIN NO MENTION OF PRECIP. HIGH CLOUDS WILL CONTINUE TO STREAM FROM THE NORTHWEST TO SOUTHEAST OVERNIGHT BUT LOW CLOUDS WILL BE THE PRIMARY CONCERN...ESPECIALLY SOUTH OF KSJT AND KBBD. PATCHY FOG WILL BE POSSIBLE INTI ALLY TONIGHT...MAINLY AFTER 06Z...WITH STRATUS DEVELOPING AT BOTH KSOA AND KJCT NEAR OR BEFORE 12Z. FARTHER NORTH...WE COULD SEE AN HOUR OR TWO OF MVFR CONDITIONS AS STRATO CU DEVELOP AFTER SUNRISE...CLOSER TO 14-15Z. BY 15-16Z...VFR CONDITIONS ARE ANTICIPATED ACROSS WEST CENTRAL TEXAS WITH AN AFTERNOON CU FIELD AROUND 6 KFT. GENERALLY SOUTH WINDS ARE EXPECTED TO REMAIN AROUND 10 KTS OR LESS...FOLLOWING OUR TYPICAL DIURNAL TREND OF VEERING TO THE SOUTHWEST IN THE MORNING AND BACKING TO THE SOUTHEAST DURING THE LATE AFTERNOON AND EVENING HOURS. JOHNSON PREV DISCUSSION... /ISSUED 340 PM CDT FRI JUL 19 2013/ SHORT TERM... MUCH QUIETER PATTERN ACROSS WEST CENTRAL TEXAS THIS AFTERNOON... WEST CENTRAL TEXAS IS BETWEEN SYSTEMS THIS AFTERNOON...WITH THE UPPER LOW THAT BROUGHT MUCH NEEDED RAINFALL TO THE AREA NOW ACROSS NORTHWEST MEXICO...AND A SECOND UPPER LOW WORKING ITS WAY INTO LOUISIANA. SUBSTANTIAL CUMULUS FIELD ACROSS THE AREA THIS AFTERNOON...BUT THIS CLOUD COVER IS NOT LEADING TO ANY SHOWERS OR STORMS. VERY LITTLE ENHANCEMENT TO THIS CU FIELD...SO CHANCES OF ANY DEVELOPMENT ARE SMALL...BUT NOT ZERO...THROUGH SUNSET. THERE IS CONVECTION ACROSS EAST TEXAS FROM THE LOUISIANA SYSTEM ACROSS EAST TEXAS THIS AFTERNOON...AND EXPECT IT TO MAKE A RUN TOWARDS THE HEARTLAND BY SATURDAY AFTERNOON. HOWEVER...LATEST GLOBAL MODELS AND THE TTU WRF SUGGEST IT WONT QUITE MAKE IT. WILL KEEP POPS OUT OF THE FORECAST FOR NOW. OTHERWISE...WARM AND MOIST AIR MASS TO REMAIN IN PLACE. A LITTLE MORE SUN IS ALLOWING TEMPERATURES TO CLIMB THIS AFTERNOON...AND MORE OF THE SAME FOR SATURDAY. LONG TERM... /SUNDAY THROUGH FRIDAY/ THE MAIN QUESTION IN THE LONG TERM IS WHAT EFFECTS THE RECENT RAINFALL WILL HAVE ON TEMPERATURES. BUT FIRST...THERE IS A VERY SLIGHT CHANCE FOR RAIN SUNDAY NIGHT AS A WEAKNESS IN THE RIDGE DEVELOPS. ALL OF THE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE WEAKNESS DEVELOPING OVER WEST TEXAS AND A LOW DEVELOPING OVER NORTHERN MEXICO. PREVIOUS MODEL RUNS WERE SUGGESTING THE RAIN WOULD BE ON MONDAY. LOOKING AT THE GFS ENSEMBLES 12 HOUR RAIN PROBABILITIES...IT HAS SLIGHTLY BETTER CHANCES SUNDAY NIGHT AND BACKS OFF FOR MONDAY. THE ECMWF DETERMINISTIC MODEL IS SLIGHTLY WETTER THAN THE GFS. GIVEN THE LACK OF MUCH SUPPORT AT THE SURFACE TO INITIATE ANYTHING...I AM GOING WITH MORE OF THE GFS...NAM SOLUTION AND HAVE SOME SLIGHT CHANCES ACROSS THE NORTHERN EDWARDS PLATEAU AND NORTHWEST HILL COUNTRY SUNDAY NIGHT. OTHERWISE...THE RIDGE BUILDS BACK IN AND TEMPERATURES WARM THROUGH THE END OF NEXT WEEK AS WE BEGIN TO DRY OUT. THE AIR SHOULD STAY FAIRLY MOIST AS IT WILL TAKE A WHILE FOR THE THE SOIL MOISTURE TO RETURN TO A MORE NORMAL LEVEL FOLLOWING THE RAIN THIS WEEK. WINDS WILL STAY OUT OF THE SOUTH TO SOUTHEAST...SO I WOULD NOT EXPECT TO SEE RAPID DRYING. SOME OF THE MODEL GUIDANCE IS TRYING TO TAKE TEMPERATURES JUST OVER 100 DEGREES...BUT THIS IS OVER THE AREA THAT HAS RECEIVED THE HIGHER RAIN AMOUNTS. GIVEN THAT THE HIGHER SOIL MOISTURE SHOULD HELP TO KEEP TEMPERATURES JUST A BIT COOLER...I HAVE TENDED TEMPERATURES TOWARDS THE RAW GFS SOLUTION WITH TEMPERATURES IN THE MID TO UPPER 90S. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 71 94 72 94 72 / 10 10 5 5 10 SAN ANGELO 69 93 71 94 71 / 10 10 5 10 10 JUNCTION 69 93 70 93 71 / 10 10 10 10 20 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 25
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1016 PM EDT SUN JUL 21 2013 .SYNOPSIS... A WEAK COLD FRONT WILL DRIFT SOUTHEAST TOWARD THE AREA TONIGHT AND MONDAY...BEFORE LIFTING BACK TO THE NORTH ON TUESDAY. THE PROXIMITY OF THIS FRONT WILL INCREASE THE THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE WORKWEEK. && .NEAR TERM /THROUGH MONDAY/... AS OF 1000 PM EDT SUNDAY... FOLLOWING CLOSE TO THE HRRR WHICH HIGHLIGHTS MORE THREAT OF SHOWERS FROM SE WV EAST NORTHEAST INTO THE SOUTHERN SHENANDOAH VALLEY OVERNIGHT BEFORE DIMINISHING. KEPT ISOLATED TO NONE IN THE SOUTH. NOT MUCH CHANGE IN THE REST OF THE FORECAST AS WE SHOULD SEE PATCHY FOG WITH MOSTLY CLOUDY SKIES. OVERNIGHT LOWS WILL REMAIN ON THE MILD SIDE...GENERALLY FALLING INTO THE MID 60S TO LOW 70S. EXPECT GREATER COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY FOR MONDAY AS A STRONGER UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST. ONCE AGAIN...THE GREATEST THREAT NORTH OF INTERSTATE 81 WILL BE LOCALLY HEAVY RAIN...WITH RAINFALL RATES OF AN INCH OR MORE OVER A FEW MINUTES TIME. AS SUCH...WILL AGAIN BE CONCERNED WITH LOCALIZED FLASH FLOODING. WILL LEAVE THE DECISION OF THE TIMING AND LOCATION OF A FLASH FLOOD WATCH TO THE OVERNIGHT SHIFT...GIVING THEM AN OPPORTUNITY TO LOOK AT ANOTHER SET OF SYNOPTIC WEATHER MODELS. SOUTH OF INTERSTATE 81...WILL ALSO SEE A SLIGHTLY GREATER THREAT OF STRONG TO SEVERE THUNDERSTORMS DURING THE AFTERNOON AND EVENING DUE TO STRONGER SURFACE HEATING. STUCK PRETTY CLOSE TO MET GUIDANCE FOR AFTERNOON TEMPERATURES...WITH HIGHS REACHING THE UPPER 70S AND LOW 80S WEST...AND REACHING TO AROUND 90 ACROSS THE PIEDMONTS. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 340 PM EDT SUNDAY... WELL DEFINED SHORT WAVE CROSSES THE FORECAST AREA MONDAY NIGHT AND TUESDAY. THIS WILL KEEP A BETTER PROBABILITY OF PRECIPITATION OVERNIGHT THAN JUST THE TYPICAL DIURNAL CYCLE OF THE PAST FEW DAYS. UPPER TROF AMPLIFIES ENOUGH THAT THE FRONT WILL PUSH SOUTH OF THE FORECAST AREA ON WEDNESDAY. AS THE FRONT COMES THROUGH ON WEDNESDAY THE EXPECTING MORE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON AND EVENING. WITH THE PASSAGE OF THE SHORT WAVE...MID LEVEL TEMPERATURES COOL SLIGHTLY WHICH WILL ENHANCE THE LAPSE RATES AND INSTABILITY. LITTLE CHANGE IN DAILY HIGH AND LOW TEMPERATURES AND IN MOISTURE OF THE AIR MASS. STAYED CLOSE TO MODEL GUIDANCE FOR MAXIMUM AND MINIMUM TEMPERATURES EACH DAY. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 1140 AM EDT SUNDAY... NO CHANGE IN THE OVERALL PATTERN THROUGH THE EXTENDED PERIOD. MODELS BRINGING STRONG ENOUGH SHORT WAVE THROUGH THE EASTERN UPPER TROF ON THURSDAY TO PUSH A SURFACE FRONT INTO THE SOUTHEAST STATES. THIS WOULD BRING WINDS AROUND TO THE NORTHWEST AND NORTH. MAY NOT COMPLETELY ELIMINATE THE PROBABILITY OF PRECIPITATION FOR THE FORECAST AREA...BUT CHANCES ON THURSDAY AND FRIDAY SHOULD BE LESS THAN IN RECENT DAYS. SOME SIGNS IN THE MODELS OF ACTUAL DRIER AIR REACHING THE FORECAST AREA. SUBTLE DROP IN 850 MB TEMPERATURES BEHIND THE FRONT...OTHERWISE NEAR NORMAL FOR HIGHS AND LOWS THROUGH DAY 7/SUNDAY. SURFACE LOW PRESSURE OVER THE MISSISSIPPI VALLEY ON SATURDAY WILL APPROACH THE REGION BY SUNDAY. WINDS WILL BE BACK AROUND TO THE SOUTHWEST WITH DEEP MOISTURE RETURNING AHEAD OF THE LOW. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... AS OF 730 PM EDT SUNDAY... STILL WATCHING SHOWERS AND A FEW STORMS ACROSS MAINLY THE WESTERN FORECAST AREA. HAVE VCTS AT ROA/BCB AS A COUPLE OF STORMS WERE MOVING ACROSS CRAIG AND GILES COUNTY...ALTHOUGH THE GILES COUNTY CELL IN THE LAST 5 MINUTES HAS WEAKENED. STILL APPEARS BEST COVERAGE OF SHOWERS THIS EVENING WILL BE IN THE BLF-LWB CORRIDOR. AS WE HEAD INTO THE OVERNIGHT THE CHANCES OF SHOWERS DECREASES AND WILL MAINTAIN PERSISTANCE ON THE FORECAST FROM PREVIOUS ONE...AND HIT THE FOG HERE AT BCB AND IN LWB THE HARDEST. APPEARS THERE MAY BE ENOUGH COVERAGE OF CLOUDS TO KEEP FOG FROM BECOMING TOO MUCH OF AN ISSUE ELSEWHERE...BUT STILL MVFR TO IFR POSSIBLE...ALONG WITH POTENTIAL LOW CIGS AT BLF/LWB/BCB. COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY LOOKS BETTER MONDAY AND EVEN THOUGH THIS IS LIKELY...KEPT VCTS IN THE TAFS AND PREDOMINAT SHOWERS...AS MODELS STILL SHWOING AT LEAST SOME PERIODS OF LESS COVERAGE MAINLY EAST OF THE BLUE RIDGE. MAIN CONCERNS WITH THIS DISTURBANCE WILL AGAIN BE HEAVY RAIN...RESULTING IN PERIODIC IFR CONDITIONS AT ALL AIRPORTS. A FEW SEVERE STORMS WILL ALSO BE POSSIBLE...MORE SO FOR DAN AND LYH WHERE STRONGER DAYTIME HEATING WILL ADD TO ATMOSPHERIC INSTABILITY DURING THE AFTERNOON. MODELS CONTINUE TO DEPICT THE STALLED FRONT HOLDING JUST NORTH OF THE AREA THROUGH EARLY TUESDAY...BEFORE LIFTING AS A LOW PRESSURE SYSTEM MOVES ACROSS THE WESTERN GREAT LAKES. REGARDLESS...EXPECT DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS TO PERSIST THROUGH THE COMING WORKWEEK AS GULF MOISTURE REMAINS ABUNDANT ACROSS THE AREA. ANOTHER COLD FRONT WILL APPROACH THE OHIO RIVER TOWARD THE END OF THE WORKWEEK...BUT DO NOT SEE THE FRONT ADVANCING MUCH FURTHER SOUTH THAN THAT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/NF NEAR TERM...NF/WP SHORT TERM...AMS/RCS LONG TERM...AMS AVIATION...NF/WP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
601 PM CDT SAT JUL 20 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND SUNDAY ISSUED AT 247 PM CDT SAT JUL 20 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SECONDARY COLD FRONT STRETCHING FROM CENTRAL NORTH DAKOTA TO PORT WASHINGTON TO SOUTHERN LOWER MICHIGAN. SEVERAL SHORTWAVES NOTED ON WV IMAGERY FROM WESTERN WISCONSIN TO NORTH DAKOTA. THE SHORTWAVE OVER WESTERN WISCONSIN MAY BE HELPING A FEW SHOWERS POP JUST WEST OF THE FOX VALLEY THIS AFTERNOON EVEN WITHOUT MUCH INSTABILITY AND NORTH OF THE FRONTAL BOUNDARY. WILL KEEP AN ISOLATED POP MENTION OVER NORTHEAST WISCONSIN FOR THE REST OF THE AFTERNOON. PRETTY QUIET UPSTREAM UNTIL YOU REACH THE DAKOTAS. WITH SEVERAL SHORTWAVES TO PASS OVER THE REGION...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...LAST NIGHTS COLD FRONT WILL SETTLE FROM THE NORTHERN PLAINS TO FAR NORTHEAST ILLINOIS. THE 850MB FRONT WILL STALL FARTHER NORTH OVER CENTRAL WISCONSIN WHERE SEVERAL WEAK RIPPLES UPSTREAM WILL PASS OVER WITHIN WNW FLOW ALOFT. WEAK FGEN ALSO NOTED ALONG THE FRONT IN THE MODELS...BUT MODELS ARE ALSO VERY GENEROUS IN CREATING QPF ALONG THE FRONT TODAY...WHICH HAS NOT VERIFIED WELL. GIVEN VERY WEAK FORCING AND LITTLE TO NO INSTABILITY TONIGHT...AM NOT ENTHUSIASTIC ABOUT PRECIP CHANCES AND WILL LEAVE THE FORECAST AREA DRY TONIGHT EXCEPT FOR VERY LATE WHEN A FEW SPRINKLES OR LIGHT SHOWERS ARE POSSIBLE OVER CENTRAL WISCONSIN WHERE MOISTURE GETS A LITTLE MORE DEEPER THAN THE REST OF THE AREA. PLENTY OF MID CLOUDS UPSTREAM SO INCREASED SKY COVER...AND THEREFORE MIN TEMPS AS WELL. LOWS FROM THE MID 40S NORTH TO UPPER 50S SOUTH. SUNDAY...A LITTLE STRONGER SHORTWAVE WILL SWING ACROSS THE NORTHERN MISSISSIPPI VALLEY AND INTO SOUTHWEST WISCONSIN IN THE AFTERNOON. FORCING WILL REMAIN ON THE WEAKER SIDE...BUT WILL IMPROVE MARGINALLY THROUGH THE DAY WITH THE APPROACH OF THE SHORTWAVE. WILL KEEP POPS WEST OF THE FOX VALLEY AND INCREASE THEM A BIT OVER CENTRAL WISCONSIN FOR THE AFTERNOON. IF SUFFICIENT BREAKS IN THE CLOUDS OCCUR SO TEMPS CAN REACH INTO THE MID 70S...CAPES MAY REACH INTO THE 500-700 J/KG RANGE OVER CENTRAL. SO CANNOT RULE OUT THUNDER CONSIDERING THUNDERSTORMS ARE OCCURRING UPSTREAM OVER THE PLAINS. HIGHS IN THE LOW TO MID 70S UNDER PARTLY TO MOSTLY CLOUDY CONDITIONS. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY ISSUED AT 247 PM CDT SAT JUL 20 2013 AREA REMAINS UNDER NW UPPER FLOW DURING THE PERIOD AS SHORTWAVE TROFS MOVE THROUGH MEAN LONGWAVE TROF OVER E NOAM. STRONGEST OF THE SHORTWAVES MOVES THROUGH LATE MONDAY. SUFFICIENT INSTABILITY AND SHEAR FOR THUNDERSTORMS WITH GUSTY WINDS AHEAD OF ASSOCIATED COLD FRONT LATE MONDAY INTO MONDAY EVENING. BIGGEST QUESTION IS AMOUNT OF PRECIP IN WAA AHEAD OF THAT SYSTEM. GFS A BIT MORE AGRESSIVE WITH ELEVATED INSTABILITY AND APPEARS TO SUFFER FROM SOME CONVECTIVE FEEDBACK OVER S WISC LATE SUNDAY. REGARDLESS... SCATTERED SHOWERS OR STORMS EXPECTED LATE SUNDAY ASSOCIATED WITH LIFT IN WAA ZONE. COOL AIR MOVES INTO REGION BEHIND THE LATE MONDAY COLD FRONT...WITH LOW TEMPS BY TUE NIGHT FALLING WELL INTO THE 40S ACROSS THE FAR NORTH. WENT BELOW GUIDANCE MINS FOR THE PERIOD. TEMP FORECAST FOR THE REMAINDER OF THE PERIOD A BLEND OF BEST PERFORMING MODEL GUIDANCE. OUTSIDE OF TUE MAX TEMPS...MUCH OF PERIOD WILL HAVE TEMPS AOB NORMS. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 601 PM CDT SAT JUL 20 2013 MID LEVEL VFR CLOUDS WILL CONTINUE TO PASS OVER THE AREA TONIGHT INTO SUNDAY. PATCHY MVFR CIGS MAY DEVELOP LATER SUNDAY AFTERNOON OVER CENTRAL WISCONSIN WITH AREAS OF LIGHT RAIN. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......JKL AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY ISSUED AT 247 PM CDT SAT JUL 20 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SECONDARY COLD FRONT STRETCHING FROM CENTRAL NORTH DAKOTA TO PORT WASHINGTON TO SOUTHERN LOWER MICHIGAN. SEVERAL SHORTWAVES NOTED ON WV IMAGERY FROM WESTERN WISCONSIN TO NORTH DAKOTA. THE SHORTWAVE OVER WESTERN WISCONSIN MAY BE HELPING A FEW SHOWERS POP JUST WEST OF THE FOX VALLEY THIS AFTERNOON EVEN WITHOUT MUCH INSTABILITY AND NORTH OF THE FRONTAL BOUNDARY. WILL KEEP AN ISOLATED POP MENTION OVER NORTHEAST WISCONSIN FOR THE REST OF THE AFTERNOON. PRETTY QUIET UPSTREAM UNTIL YOU REACH THE DAKOTAS. WITH SEVERAL SHORTWAVES TO PASS OVER THE REGION...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...LAST NIGHTS COLD FRONT WILL SETTLE FROM THE NORTHERN PLAINS TO FAR NORTHEAST ILLINOIS. THE 850MB FRONT WILL STALL FARTHER NORTH OVER CENTRAL WISCONSIN WHERE SEVERAL WEAK RIPPLES UPSTREAM WILL PASS OVER WITHIN WNW FLOW ALOFT. WEAK FGEN ALSO NOTED ALONG THE FRONT IN THE MODELS...BUT MODELS ARE ALSO VERY GENEROUS IN CREATING QPF ALONG THE FRONT TODAY...WHICH HAS NOT VERIFIED WELL. GIVEN VERY WEAK FORCING AND LITTLE TO NO INSTABILITY TONIGHT...AM NOT ENTHUSIASTIC ABOUT PRECIP CHANCES AND WILL LEAVE THE FORECAST AREA DRY TONIGHT EXCEPT FOR VERY LATE WHEN A FEW SPRINKLES OR LIGHT SHOWERS ARE POSSIBLE OVER CENTRAL WISCONSIN WHERE MOISTURE GETS A LITTLE MORE DEEPER THAN THE REST OF THE AREA. PLENTY OF MID CLOUDS UPSTREAM SO INCREASED SKY COVER...AND THEREFORE MIN TEMPS AS WELL. LOWS FROM THE MID 40S NORTH TO UPPER 50S SOUTH. SUNDAY...A LITTLE STRONGER SHORTWAVE WILL SWING ACROSS THE NORTHERN MISSISSIPPI VALLEY AND INTO SOUTHWEST WISCONSIN IN THE AFTERNOON. FORCING WILL REMAIN ON THE WEAKER SIDE...BUT WILL IMPROVE MARGINALLY THROUGH THE DAY WITH THE APPROACH OF THE SHORTWAVE. WILL KEEP POPS WEST OF THE FOX VALLEY AND INCREASE THEM A BIT OVER CENTRAL WISCONSIN FOR THE AFTERNOON. IF SUFFICIENT BREAKS IN THE CLOUDS OCCUR SO TEMPS CAN REACH INTO THE MID 70S...CAPES MAY REACH INTO THE 500-700 J/KG RANGE OVER CENTRAL. SO CANNOT RULE OUT THUNDER CONSIDERING THUNDERSTORMS ARE OCCURRING UPSTREAM OVER THE PLAINS. HIGHS IN THE LOW TO MID 70S UNDER PARTLY TO MOSTLY CLOUDY CONDITIONS. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY ISSUED AT 247 PM CDT SAT JUL 20 2013 AREA REMAINS UNDER NW UPPER FLOW DURING THE PERIOD AS SHORTWAVE TROFS MOVE THROUGH MEAN LONGWAVE TROF OVER E NOAM. STRONGEST OF THE SHORTWAVES MOVES THROUGH LATE MONDAY. SUFFICIENT INSTABILITY AND SHEAR FOR THUNDERSTORMS WITH GUSTY WINDS AHEAD OF ASSOCIATED COLD FRONT LATE MONDAY INTO MONDAY EVENING. BIGGEST QUESTION IS AMOUNT OF PRECIP IN WAA AHEAD OF THAT SYSTEM. GFS A BIT MORE AGRESSIVE WITH ELEVATED INSTABILITY AND APPEARS TO SUFFER FROM SOME CONVECTIVE FEEDBACK OVER S WISC LATE SUNDAY. REGARDLESS... SCATTERED SHOWERS OR STORMS EXPECTED LATE SUNDAY ASSOCIATED WITH LIFT IN WAA ZONE. COOL AIR MOVES INTO REGION BEHIND THE LATE MONDAY COLD FRONT...WITH LOW TEMPS BY TUE NIGHT FALLING WELL INTO THE 40S ACROSS THE FAR NORTH. WENT BELOW GUIDANCE MINS FOR THE PERIOD. TEMP FORECAST FOR THE REMAINDER OF THE PERIOD A BLEND OF BEST PERFORMING MODEL GUIDANCE. OUTSIDE OF TUE MAX TEMPS...MUCH OF PERIOD WILL HAVE TEMPS AOB NORMS. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1231 PM CDT SAT JUL 20 2013 MID-LEVEL CLOUDS ALONG A STALLED COLD FRONT WILL GRADUALLY LOWER OVER THE NEXT 24 HOURS. THINK VFR CONDITIONS WILL HOLD OUT THOUGH...EVEN IF LIGHT SHOWERS MOVE INTO CENTRAL WISCONSIN TOMORROW MORNING. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......JKL AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1240 PM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 317 AM CDT SAT JUL 20 2013 CURRENTLY AS OF 08Z... WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON. THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA. DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT. TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z. SYNOPTIC OVERVIEW... A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD. MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING AND RIDING THROUGH THE NORTHWEST FLOW. TODAY... ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM. 925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID 80S. TONIGHT... CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT. HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH 850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF PRECIPITATION IN THE 20-40 RANGE OVERNIGHT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 317 AM CDT SAT JUL 20 2013 SYNOPTIC OVERVIEW... 20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE RIDGE FROM BUILDING UP INTO THE FORECAST AREA. SUNDAY INTO MONDAY NIGHT... THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING. HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING. 20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY. ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS. 925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH: 1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA. 2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT. 3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH. GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE 40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS. CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH. TUESDAY THROUGH FRIDAY NIGHT... DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY... WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY. 850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE. ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR NEXT WEEKEND. && .AVIATION...THROUGH 18Z SUNDAY 1240 PM CDT SAT JUL 20 2013 SOME REMNANT MID-HIGH CLOUD ACROSS THE TAF LOCATIONS AT MID-DAY... LEFTOVER FROM STORMS THAT FIRED OVER SD. THIS SHOULD CLEAR BY MID- AFTERNOON. MEANWHILE...ANOTHER BAND OF SHOWERS OVER WESTERN MN ARE TRACKING THIS WAY. WEAK SHORT WAVE TROUGH ENERGY SEEN IN WATER VAPOR IMAGERY EXPECTED TO CROSS THE AREA BY EVENING...AND ANOTHER DISTURBANCE ANTICIPATED OVERNIGHT. SEVERAL WEAK BOUNDARIES LYING AROUND THE REGION TO ASSIST ON FOCUSING CONVECTIVE POTENTIAL. THE STRONGEST OF WHICH IS A COOL FRONT ADVANCING SOUTH-SOUTHWEST ACROSS NORTHERN WI AND CENTRAL MN. EXPECT THE DISTURBANCE THIS AFTERNOON WILL MAXIMIZE POTENTIAL DURING PEAK HEATING AND COULD RESULT IN SHOWERS AND ISOLATED THUNDERSTORMS. BETTER CHANCES EXIST OVER SOUTHEAST MN...BUT EVEN THAT IS REMOTE. THE SECOND WAVE TONIGHT WILL BRING A BETTER AND MORE WIDESPREAD RISK OF SHRA/TSRA. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...MW
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
650 AM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 317 AM CDT SAT JUL 20 2013 CURRENTLY AS OF 08Z... WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON. THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA. DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT. TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z. SYNOPTIC OVERVIEW... A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD. MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING AND RIDING THROUGH THE NORTHWEST FLOW. TODAY... ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM. 925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID 80S. TONIGHT... CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT. HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH 850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF PRECIPITATION IN THE 20-40 RANGE OVERNIGHT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 317 AM CDT SAT JUL 20 2013 SYNOPTIC OVERVIEW... 20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE RIDGE FROM BUILDING UP INTO THE FORECAST AREA. SUNDAY INTO MONDAY NIGHT... THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING. HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING. 20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY. ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS. 925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH: 1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA. 2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT. 3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH. GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE 40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS. CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH. TUESDAY THROUGH FRIDAY NIGHT... DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY... WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY. 850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE. ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR NEXT WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 650 AM CDT SAT JUL 20 2013 VFR CONDITIONS EXPECTED AT THE TAF SITES TODAY ALONG WITH THE POSSIBILITY OF SCATTERED THUNDERSTORMS DURING THE AFTERNOON AND EARLY EVENING HOURS. A WEAK TROUGH WILL SAG SOUTH OUT OF NORTHERN WISCONSIN TODAY AND POSSIBLY GENERATE SCATTERED THUNDERSTORMS THIS AFTERNOON AS IT DRIFTS SOUTH THROUGH SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN. IF STORMS DEVELOP...THEY MAY PRODUCE GUSTY WINDS AND SMALL HAIL. OTHERWISE PLAN ON A SCATTERED TO BROKEN CEILINGS AT THE TAF SITES TODAY...WITH CLOUDS INCREASING DURING THE AFTERNOON HOURS WITH CLOUD BASES IN THE 5 TO 8 KFT RANGE. SHOWERS AND THUNDERSTORMS ARE POSSIBLE AGAIN LATE TONIGHT INTO SUNDAY MORNING AS AN UPPER LEVEL TROUGH MOVES THROUGH THE AREA. THE BULK OF THE ACTIVITY SHOULD OCCUR AFTER 12Z...WITH THE HIGHEST CHANCES FOR SHOWERS AND STORMS SUNDAY AFTERNOON. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
317 AM CDT SAT JUL 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 317 AM CDT SAT JUL 20 2013 CURRENTLY AS OF 08Z... WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON. THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA. DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT. TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z. SYNOPTIC OVERVIEW... A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD. MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING AND RIDING THROUGH THE NORTHWEST FLOW. TODAY... ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM. 925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID 80S. TONIGHT... CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT. HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH 850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF PRECIPITATION IN THE 20-40 RANGE OVERNIGHT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 317 AM CDT SAT JUL 20 2013 SYNOPTIC OVERVIEW... 20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE RIDGE FROM BUILDING UP INTO THE FORECAST AREA. SUNDAY INTO MONDAY NIGHT... THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING. HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING. 20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY. ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS. 925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH: 1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA. 2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT. 3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH. GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE 40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS. CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH. TUESDAY THROUGH FRIDAY NIGHT... DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY... WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY. 850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE. ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR NEXT WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1050 PM CDT FRI JUL 19 2013 SOME UPPER LEVEL FORCING...COUPLED WITH A BIT OF LOW LEVEL MOISTURE CONVERGENCE/INSTABILTY...WAS SPARKING A SMALL AREA OF SHRA/TS OVER CENTRAL MN. IT LOOKS LIKE THIS WILL HOLD TOGETHER FOR THE OVERNIGHT HOURS...WORKING INTO WESTERN WI. BELIEVE THE PCPN WILL STAY NORTH OF THE TAF SITES AT THIS MOMENT...SO WILL LEAVE ANY MENTION OUT OF THE FORECAST. GENERALLY VFR THOUGH THE DAY...BUT CLOUDS WILL BE ON THE INCREASE FROM THE WEST THANKS TO ANOTHER UPPER LEVEL FEATURE. SOME SHRA/TS ARE ALSO POSSIBLE...WHICH COULD IMPACT KRST. COVERAGE COULD BE MORE SCATTERED THOUGH...AND CONFIDENCE ISN/T HIGH ENOUGH TO ADD SHRA OR VCSH YET. SOMETHING TO MONITOR. CLOUDS WILL CONTINUE TO INCREASE AND THICKEN FROM THE WEST SAT NIGHT...BUT LOOKS TO STAY VFR. RAIN CHANCES WILL INCREASE FOR SUN/MON THANKS TO A FEW DIFFERENT WEATHER TRIGGERS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1144 AM MDT SAT JUL 20 2013 .UPDATE... ISSUED AT 1041 AM MDT SAT JUL 20 2013 SOME SHOWERS AND THUNDERSTORMS CONTINUE AS OF 16Z OVER THE NORTHERN PANHANDLE. THE ACTIVITY HAS BEEN MOVING SOUTHEAST AND SLOWLY DECREASING IN COVERAGE AND INTENSITY. FORECAST FOR THE AFTERNOON AND EVENING LOOKS TO BE ON TRACK WITH STRONG STORMS MAINLY EAST OF THE LARAMIE RANGE AND WARMER TEMPERATURES. A SURFACE BOUNDARY HAS MOVED ACROSS THE CWA TO THE EAST OF THE LARAMIE RANGE AND WAS POSSIBLY PUSHED SOUTH FROM OUTFLOW FROM THE ACTIVITY OVER THE NORTH PART OF THE CWA. THE BOUNDARY LOOKS TO END UP ALONG THE LARAMIE RANGE AND SHOULD PROVIDE THE FOCUS FOR STORM DEVELOPMENT BY EARLY IN THE AFTERNOON. AS THE STORMS MOVE OFF THE LARAMIE RANGE...THE ENVIRONMENT WILL BE MOIST AND UNSTABLE. PRECIPITABLE WATER VALUES WILL BE AROUND AN INCH AND THE 250MB JET JUST TO THE NORTH OF THE CWA WILL BE PRESENT. THIS SITUATION IS DIFFERENT THAN IN RECENT WEEKS AND PERHAPS MORE SIMILAR TO EARLY SUMMER WITH BETTER 0-6KM SHEAR ALLOWING FOR SUPERCELL DEVELOPMENT. THE STORMS WILL PRODUCE HEAVY RAIN... HAIL...STRONG WIND GUSTS AND FREQUENT LIGHTNING. SEVERE WEATHER WILL BE POSSIBLE OVER THE PANHANDLE WITH LARGER HAIL AND WIND GUST TO 60 MPH. THE HEAVY RAIN WILL CREATE LOCAL AREAS OF FLOODING. CONSIDERED A FLASH FLOOD WATCH...BUT WILL WAIT UNTIL AT LEAST STORMS START DEVELOPING. THE STORMS SHOULD BE MOVING OVER THE SOUTHEAST WYOMING PLAINS EARLY IN THE AFTERNOON AND BE EAST OF THAT AREA BY LATE AFTERNOON OR EARLY EVENING. THE ACTIVITY WILL CONTINUE THROUGH AT LEAST THE L;ATE EVENING OVER THE PANHANDLE. IN A RECENT UPDATE...BUMPED UP POPS SOME OVER THE EASTERN CWA AND ADDED THE MENTION OF HEAVY RAIN AND SMALL HAIL OVER THE SOUTHEAST WYOMING PLAINS. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 230 AM MDT SAT JUL 20 2013 FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE POSSIBILITIES THIS AFTERNOON. CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON. HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE CWFA...SKIES ARE PRETTY MUCH CLEAR. SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY 21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO -5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH THIS CLOSELY. FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT. SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING EAST OF THE LARAMIE RANGE. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 111 AM MDT SAT JUL 20 2013 MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE 50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST AREA ON TUESDAY. FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15 PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING) ISSUED AT 1144 AM MDT SAT JUL 20 2013 MAIN AVIATION IMPACT WILL BE THE THREAT FOR SHOWERS AND THUNDERSTORMS AND RESULTANT MVFR VSBYS THIS AFTERNOON AND EVENING. THIS WILL ESPECIALLY BE THE CASE FOR TERMINALS TO THE EAST OF THE LARAMIE RANGE WHERE THE ATMOSPHERE WILL BE MOST FAVORABLE. AS OF 1745Z...CONVECTION HAS JUST BEGAN TO DEVELOP OFF THE SOUTHEAST WYOMING MOUNTAINS. THIS TREND WILL CONTINUE AS THUNDERSTORMS BECOME MORE NUMEROUS THIS AFTERNOON. THESE THUNDERSTORMS ARE NOT ANTICIPATED TO AFFECT AIRFIELDS UNTIL AFTER 20Z OR 21Z. COVERAGE WILL BE SUFFICIENT ENOUGH TO INCLUDE A TEMPO GROUP AT MOST SITES. SHOWERS AND THUNDERSTORMS WILL LIKELY PUSH SOUTH AND EAST OF THE AIRFIELDS BY 02Z OR 03Z...WITH GRADUAL IMPROVEMENT ANTICIPATED THEREAFTER. A FEW OF THE STRONGEST THUNDERSTORMS MAY CONTAIN LARGE HAIL AND DAMAGING WINDS... ESPECIALLY AT WESTERN NEBRASKA PANHANDLE SITES. && .FIRE WEATHER... ISSUED AT 230 AM MDT SAT JUL 20 2013 ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...WEILAND SHORT TERM...CLAYCOMB LONG TERM...TJT AVIATION...HAHN FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1041 AM MDT SAT JUL 20 2013 .UPDATE... ISSUED AT 1041 AM MDT SAT JUL 20 2013 SOME SHOWERS AND THUNDERSTORMS CONRINUE AS OF 16Z OVER THE NORTHERN PANHANDLE. THE ACTIVITY HAS BEEN MOVING SOUTHEAST AND SLOWLY DECREASING IN COVERAGE AND INTENSITY. FORECAST FOR THE AFTERNOON AND EVENING LOOKS TO BE ON TRACK WITH STRONG STORMS MAINLY EAST OF THE LARAMIE RANGE AND WARMER TEMPERATURES. A SURFACE BOUNDARY HAS MOVED ACROSS THE CWA TO THE EAST OF THE LARAMIE RANGE AND WAS POSSIBLY PUSHED SOUTH FROM OUTFLOW FROM THE ACTIVITY OVER THE NORTH PART OF THE CWA. THE BOUNDARY LOOKS TO END UP ALONG THE LARAMIE RANGE AND SHOULD PROVIDE THE FOCUS FOR STORM DEVELOPMENT BY EARLY IN THE AFTERNOON. AS THE STORMS MOVE OFF THE LARAMIE RANGE...THE ENVIRONMENT WILL BE MOIST AND UNSTABLE. PRECIPITABLE WATER VALUES WILL BE AROUND AN INCH AND THE 250MB JET JUST TO THE NORTH OF THE CWA WILL BE PRESENT. THIS SITUATION IS DIFFERENT THAN IN RECENT WEEKS AND PERHAPS MORE SIMILAR TO EARLY SUMMER WITH BETTER 0-6KM SHEAR ALLOWING FOR SUPERCELL DEVELOPMENT. THE STORMS WILL PRODUCE HEAVY RAIN... HAIL...STRONG WIND GUSTS AND FREQUENT LIGHTNING. SEVERE WEATHER WILL BE POSSIBLE OVER THE PANHANDLE WITH LARGER HAIL AND WIND GUST TO 60 MPH. THE HEAVY RAIN WILL CREATE LOCAL AREAS OF FLOODING. CONSIDERED A FLASH FLOOD WATCH...BUT WILL WAIT UNTIL AT LEAST STORMS START DEVELOPING. THE STORMS SHOULD BE MOVING OVER THE SOUTHEAST WYOMING PLAINS EARLY IN THE AFTERNOON AND BE EAST OF THAT AREA BY LATE AFTERNOON OR EARLY EVENING. THE ACTIVITY WILL CONTINUE THROUGH AT LEAST THE L;ATE EVENING OVER THE PANHANDLE. IN A RECENT UPDATE...BUMPED UP POPS SOME OVER THE EASTERN CWA AND ADDED THE MENTION OF HEAVY RAIN AND SMALL HAIL OVER THE SOUTHEAST WYOMING PLAINS. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 230 AM MDT SAT JUL 20 2013 FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE POSSIBILITIES THIS AFTERNOON. CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON. HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE CWFA...SKIES ARE PRETTY MUCH CLEAR. SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY 21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO -5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH THIS CLOSELY. FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT. SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING EAST OF THE LARAMIE RANGE. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 111 AM MDT SAT JUL 20 2013 MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE 50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST AREA ON TUESDAY. FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15 PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK. && .AVIATION...(FOR THE 12Z TAF ISSUANCE) VFR CONDITIONS WILL PREVAIL THIS MORNING THROUGH 18Z. SURFACE WINDS WILL BE VARIABLE AT 10 KT OR LESS WITH CLEAR SKIES. THERE IS A BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS INTO WESTERN NEBRASKA THIS AFTERNOON...MAINLY EAST OF THE LARAMIE RANGE. STRONG GUSTY WINDS...FREQUENT LIGHTNING...AND SMALL HAIL WILL BE THE MAIN CONCERNS WITH THESE THUNDERSTORMS THROUGH THIS EVENING. && .FIRE WEATHER... ISSUED AT 230 AM MDT SAT JUL 20 2013 ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...WEILAND SHORT TERM...CLAYCOMB LONG TERM...TJT AVIATION...TJT FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
552 AM MDT SAT JUL 20 2013 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 230 AM MDT SAT JUL 20 2013 FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE POSSIBILITIES THIS AFTERNOON. CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON. HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE CWFA...SKIES ARE PRETTY MUCH CLEAR. SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY 21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO -5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH THIS CLOSELY. FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT. SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING EAST OF THE LARAMIE RANGE. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 111 AM MDT SAT JUL 20 2013 MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE 50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST AREA ON TUESDAY. FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15 PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK. && .AVIATION...(FOR THE 12Z TAF ISSUANCE) VFR CONDITIONS WILL PREVAIL THIS MORNING THROUGH 18Z. SURFACE WINDS WILL BE VARIABLE AT 10 KT OR LESS WITH CLEAR SKIES. THERE IS A BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS INTO WESTERN NEBRASKA THIS AFTERNOON...MAINLY EAST OF THE LARAMIE RANGE. STRONG GUSTY WINDS...FREQUENT LIGHTNING...AND SMALL HAIL WILL BE THE MAIN CONCERNS WITH THESE THUNDERSTORMS THROUGH THIS EVENING. && .FIRE WEATHER... ISSUED AT 230 AM MDT SAT JUL 20 2013 ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CLAYCOMB LONG TERM...TJT AVIATION...TJT FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
252 AM MDT SAT JUL 20 2013 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 230 AM MDT SAT JUL 20 2013 FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE POSSIBILITIES THIS AFTERNOON. CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON. HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE CWFA...SKIES ARE PRETTY MUCH CLEAR. SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY 21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO -5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH THIS CLOSELY. FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT. SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING EAST OF THE LARAMIE RANGE. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 111 AM MDT SAT JUL 20 2013 MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE 50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST AREA ON TUESDAY. FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15 PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1150 PM MDT FRI JUL 19 2013 VFR CONDITIONS WILL PREVAIL TONIGHT THROUGH 18Z SATURDAY. SURFACE WINDS WILL BE VARIABLE 10 KT OR LESS WITH CLEAR SKIES. THERE IS A BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS INTO WESTERN NEBRASKA SATURDAY AFTERNOON. ADDED VCTS TO THE FORECAST FOR NOW SINCE TIMING OF THESE THUNDERSTORMS IS RATHER UNCERTAIN TONIGHT. && .FIRE WEATHER... ISSUED AT 230 AM MDT SAT JUL 20 2013 ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CLAYCOMB LONG TERM...TJT AVIATION...TJT FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1110 PM MDT SUN JUL 21 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 304 PM MDT SUN JUL 21 2013 DRIER AIR MASS HAS SPREAD OVER THE NORTHERN AND WESTERN PORTIONS OF THE AREA THIS AFTERNOON...DROPPING DEW POINTS INTO THE 20S OVER THE CENTRAL MOUNTAINS AND ACROSS TELLER COUNTY. LOW LEVEL MOISTURE STILL LURKS ON THE PLAINS...WHERE DEWPOINTS IN THE 50S HAVE LED TO CAPES IN EXCESS OF 2K J/KG EAST OF I-25. VERY LITTLE IN THE WAY OF FORCING/UPWARD MOTION THIS AFTERNOON...WITH ONLY VERY SPARSE MOUNTAIN CONVECTION MAINLY SOUTH OF HIGHWAY 50. HAVE ALSO SEEN A COUPLE CELLS DEVELOP THEN DISSIPATE QUICKLY OVER EASTERN EL PASO COUNTY...WHERE MOISTURE GRADIENT IS FAIRLY TIGHT AND RESIDUAL BOUNDARY FROM LAST NIGHT`S CONVECTION REMAINS. LATEST HRRR HINTS AT TSRA DEVELOPING EAST OF I-25 THIS EVENING....AND WHILE FORCING IS WEAK...LARGE CAPES ARE HARD TO IGNORE...AND WILL THROW IN SOME LOW POPS FOR THE PLAINS EARLY THIS EVENING. STILL EXPECT ANY STORMS TO DISSIPATE QUICKLY AFTER SUNSET. ON MONDAY...AIR MASS CONTINUES TO DRY...AND EVEN THE MOUNTAINS WILL BE HARD PRESSED TO SEE MORE THAN SOME MODERATE CUMULUS BUILD-UP IN THE AFTERNOON. KEPT SOME VERY LOW POPS IN PLACE OVER THE HIGHER PEAKS...BUT EVEN THESE MAY BE OVERDONE. RISING HEIGHTS AND MID-LEVEL TEMPS SUGGEST A HOT DAY IS IN STORE...AS READINGS ON THE PLAINS REACH 100F...WITH 80/90S ELSEWHERE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 304 PM MDT SUN JUL 21 2013 THE ENTIRE EXTENDED FORECAST PERIOD CAN BE SUMMED UP IN TWO SENTENCES. AN UPPER RIDGE OF HIGH PRESSURE WILL REMAIN LOCKED INTO PLACE ACROSS THE REGION. MINOR DISTURBANCES IN THE FLOW ALOFT ROTATING AROUND THE RIDGE WILL KICK OFF ENHANCED CONVECTION TOWARDS THE LATTER HALF OF THE WEEK. NOW FOR THE SPECIFICS... MONDAY NIGHT THROUGH TUESDAY...EC...GFS AND EVEN THE NAM MODEL ARE NOW INDICATING THAT IT SHOULD REMAIN FAIRLY DRY THROUGH MUCH OF TUE...WITH ISOLATED TO LOW END SCATTERED POPS OVER THE HIGHER TERRAIN. A COLD FRONT DROPS DOWN TO THE PALMER DVD ON TUE...BUT THE LATEST RUNS INDICATE IT DOES NOT DROP SOUTH UNTIL LATE TUE...SETTING THE STAGE FOR WED. LOOK FOR MAX TEMPS ACROSS THE E PLAINS TO BE AROUND 100 DEG F ON TUE...AND IN THE MID TO UPPER 80S FOR THE HIGH VALLEYS. WEDNESDAY THROUGH FRIDAY...THE COLD FRONT WILL DROP SOUTH ACROSS THE CWA LATE TUE...WITH WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY EXPECTED FOR A MAJORITY OF THE FORECAST AREA BOTH WED AND THU. MAX TEMPS ARE EXPECTED TO BE ABOUT 10 DEGREES COOLER WITH SCATTERED POPS ALL AREAS BORDERING ON LIKELY. WED AFTN THROUGH THU AFTN LOOKS LIKE IT WILL BE THE MOST PROBABLY TIME FRAME FOR FLASH FLOOD POTENTIAL ACROSS AREA BURN SCARS. BY FRIDAY THE UPPER RIDGE AXIS STARTS TO SHIFT SLIGHTLY TO THE EAST AS THE RIDGE AMPLIFIES...AND THOUGH THERE IS STILL A GOOD CHANCE FOR CONVECTION FOR ALL AREAS...IT WILL BE DUE TO A REINFORCED MONSOON PLUME AS OPPOSED TO FRONTAL/LLVL FORCING. TEMPS ON FRI WILL BE AS COOL OR PERHAPS EVEN A COUPLE OF DEGREES COOLER. SATURDAY AND SUNDAY...EXTENDED MODELS ARE POINTING TO ANOTHER STRONGER DISTURBANCE MOVING ACROSS THE DAKOTAS AND MIDWEST ON SAT...PUSHING ANOTHER COLD SURGE INTO EASTERN CO LATE SAT INTO SUN. WHEREAS SAT IS FORECAST TO HAVE DIURNAL CONVECTIVE ACTIVITY TIED MAINLY TO THE HIGHER TERRAIN...SUNDAY COULD BE ANOTHER ACTIVE DAY WITH WIDESPREAD CONVECTION AND SLIGHTLY COOLER TEMPS. MOORE && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1110 PM MDT SUN JUL 21 2013 UPPER HIGH EXPECTED TO AMPLIFY ACROSS THE GREAT BASIN DRIER WITHIN THE WEAK NORTHERLY FLOW ALOFT PUSHING MONSOONAL MOISTURE PLUME SOUTH AND WEST OF THE AREA THROUGH THE DAY TOMORROW. THIS WILL KEEP VFR CONDTIONS IN PLACE AT TAF SITES WITH ISOLATED MAINLY HIGH BASED CONVECTION EXPECTED TO STAY OVER AND NEAR THE HIGHER TERRAIN. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...MOORE AVIATION...MW
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
356 AM EDT Mon Jul 22 2013 .NEAR TERM [Through Today]... The large scale longwave pattern is highlighted by weak ridging over Wrn Conus and a broad upper level trough across much of the Cntrl and Ern U.S. Several shortwaves were noted in water vapor imagery moving across base of trough including one over NW AL. At the surface, a ridge of high pressure extends from the Atlc WWD across the FL Peninsula and Cntrl Gulf of Mexico. A weak and dissipating trough was noted across the WRN forecast area. 24hr temp/dew point comparisons indicate little change in airmass last 24 hrs. Latest radar pix shows less convection than forecast developing over the Gulf waters. Still, HRRR and WRF show marine convection moving onshore after 10z from Panhandle waters reaching FL/AL border by 14z. Have updated 06z-12z Grids to lower POPS and will monitor in case another update is needed. During the rest of today, progressive WSW steering flow as unseasonably amplified upper trough digs SEWD into TN Valley and deepens increasing tropical moisture plume, aided by AL shortwave moving ESE provides additional lift. Surface ridge remains to our S locally yielding SW flow. PWATs across the region from JAX west to Dothan and beyond in excess of 2 inches this aftn. This will combine with seabreeze/mesoscale outflows clashes from leftover boundaries from surface trough for sct/numerous showers and thunderstorms later today. As reflected in CAM and other models, highest POPs over the NW zones closest to the upper energy. Will go with 40-80% SE-NW POP gradient. RAP13 soundings show uni- directional very moist profiles which favor good rain producers and given recent rains, aggravate chances of at least nuisance flooding again today. CAM QPF/flood tools shows Panhandle as best bet with 1-2 inches avg STP. Although Shear unimpressive, model aftn CAPE around 2400 J/KG across SE AL. Add presence of shortwave plus any boundary clashes this favors at least strong storms to isold severe storms with best bet SE AL/ adjacent GA/FL 21z-00z. This, along with max temps will be partly dependent on amount of morning cloudiness and where drier air sets making max temp forecast a little tricky. Inland Highs generally 88 to 90. && .SHORT TERM [Tonight through Wednesday]... The pattern will transition to more of a northwest flow aloft through the short term as the upper level trough axis moves east of the area. A series of shortwaves is expected to move through the base of the trough and aid in convective development over the forecast area (PoPs 40-60% during the day). The northwest flow aloft will also aid in advecting steeper than normal mid-level lapse rates into the area by Tuesday into Wednesday, which may increase the threat of isolated, pulse severe storms. These would be most likely over the northern and western portions of the area. The 22/00z GFS forecasts 700-500 mb lapse rates between 6-7 C/km, which is 1-1.5 C/km above climo for this time of year. && .LONG TERM [Wednesday Night through Sunday]... The upper flow across the CONUS will be dominated by an eastern trough and western ridge. Through most of the extended period, the upper trough axis is forecast to be just east of the CWA, with northwest flow aloft. While this flow is typically drier across the region, the presence of a nearly stationary trough across the northern half of the area will offset this to some extent. With this in mind, will generally keep the PoPs at or below 50 percent through the extended, especially for Thursday into the weekend. With the slightly lower rain chances than the past several days, expect high temperatures to creep back into the lower to mid 90s as well. && .AVIATION... [Through 06z Tuesday] Although locales remain VFR at 07z, HRRR show showers and thunderstorms developing at our western terminals aft 09z and spreading E/NE reaching the FL/AL border thru 14z. Therefore decided to include MVFR CIGS/VSBYS 09Z-14z except possibly at ECP with brief IFR/LIFR CIGs possible until around sunrise. After morning showers and thunderstorms diminish, there will likely be a break, and then another round in the afternoon with conditions very similar to what we saw on Sun with MVFR CIGS/VSBYS and gusty winds in any heavy rain or strong storms. && .MARINE... With a persistent trough to the north and high pressure to the south, winds over the marine area will be primarily out of the southwest to west-southwest this week between 10 and 15 knots. && .FIRE WEATHER... Red flag conditions are not expected for the next several days. && .HYDROLOGY... A few rivers still remain at or near flood stage, including the Aucilla and Econfina rivers. The Steinhatchee river is also out of its banks south of US 19 with minor flooding expected downstream of the gage for the next day or two. Scattered showers and storms are expected through much of this week, but should not be sufficient to produce widespread flooding. However, localized areas of heavy rain are likely and could cause some urban and small stream flooding on occasion. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 89 74 92 74 93 / 60 50 60 50 50 Panama City 86 76 88 76 88 / 60 50 60 40 50 Dothan 88 73 92 73 91 / 70 40 60 50 50 Albany 89 73 92 74 92 / 70 40 60 40 50 Valdosta 89 73 92 74 94 / 70 40 60 40 50 Cross City 89 73 88 73 90 / 50 40 60 40 50 Apalachicola 86 77 88 77 90 / 60 50 60 40 50 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Risk for Rip Currents for FLZ108-112-114. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Wx...Block Short Term/Marine/Hydrology...DVD Long Term...Camp
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1150 PM CDT SUN JUL 21 2013 .DISCUSSION... ISSUED 850 PM CDT SUN JUL 21 2013 UPDATED THE FORECAST TONIGHT TO INCREASE CHANCES OF SHOWERS ALONG WITH A FEW THUNDERSTORMS. ALSO NUDGED UP LOW TEMPERATURES A DEGREE OR TWO TO AROUND 70F...DUE TO MOIST DEWPOINTS CURRENTLY IN THE LOW TO MID 70S. A FEW POCKETS OF LOCALLY HEAVY RAINS OF 1.5 TO 3 INCHES ALSO TO OCCUR TONIGHT ESPECIALLY FROM I-72 SOUTH...AS JACKSONVILLE HAS EXPERIENCED SINCE 5 PM. THE HRRR MODEL HAS BEEN HANDLING THIS WEATHER SYSTEM THE BEST SO FAR SO LEANED ON THIS MODEL FOR TONIGHT`S FORECAST. SHOWERS AND A FEW THUNDERSTORMS TO SPREAD INTO EASTCENTRAL IL NEXT NEW HOURS... THEN DIMINISH FROM WEST TO EAST LATE THIS EVENING AND OVERNIGHT. A SHORT WAVE MOVING INTO CENTRAL IL THIS EVENING AND EXITING SE OF AREA MONDAY MORNING WILL KEEP LIKELY CHANCES OF SHOWERS AND FEW THUNDERSTORMS PAST SUNDOWN TONIGHT AND LIKELY CHANCES CONTINUE OVER EASTERN IL OVERNIGHT...WHILE DIMINISHING TO SLIGHT CHANCE IN THE WEST. A QUASI STATIIONARY FRONTAL BOUNDARY OVER NE PARTS OF IA/IL AND INTO CENTRAL INDIANA WILL GRADUALLY WEAKEN THROUGH MONDAY...WITH CENTRAL/SE IL STAYING ON THE SOUTH SIDE (MILD/MOIST SIDE) OF THE BOUNDARY. TEMPS CURRENTLY IN THE 70S TO ONLY SLIP TOWARD 70F FOR LOWS OVERNIGHT WHICH JACKSONVILLE IS CURRENTLY DOWN TO WITH HEAVY RAINS PAST FEW HOURS FROM THUNDERSTORMS. EXPECT LIGHT SSE TO VARIABLE WINDS TONIGHT WITH SOME FOG POSSIBLE OVERNIGHT INTO MID MORNING MONDAY WITH VSBYS DOWN TO 1-3 MILES. 07 && .AVIATION... ISSUED 1150 PM CDT SUN JUL 21 2013 IFR TO MVFR VSBYS AND CEILINGS POSSIBLE WITH SHOWERS AND A FEW THUNDERSTORMS WITH LOCALLY HEAVY RAINS THE NEXT FEW HOURS AT DEC AND CMI WHILE A FEW LIGHT SHOWERS COULD BRING MVFR CONDITIONS TIL 08Z ALONG I-55 AT BMI AND SPI. CONVECTION TIED TO A SHORT WAVE THAT IT OVER CENTRAL IL AND TO EXIT SOUTHEAST OF AREA BY DAWN. HAVE 1-3 MILES WITH FOG DEVELOPING DURING OVERNIGHT UNTIL 14-15Z MONDAY. CLEARING SKIES WORKING EASTWARD FROM MO INTO WEST CENTRAL IL AROUND QUINCY LATE THIS EVENING. IF CLEARING SKIES TO GET INTO WESTERN TAF SITES OF PIA AND SPI AFTER 08Z WHERE FOG COULD BECOME MORE WIDESPREAD WITH PATCHY DENSE FOG EVEN POSSIBLE...THOUGH DID NOT CARRY VSBYS THAT LOW DUE TO UNCERTAINTY OF CLEARING ESPECIALLY OVER EASTERN TAF SITES. ANY LINGERING LOW CLOUDS AND FOG SHOULD LIFT AFTER 14-15Z MONDAY MORNING WITH BROKEN MVFR CEILINGS LINGERING LONGEST AT CMI POSSIBLY INTO MIDDAY. FAIR WEATHER EXPECTED MONDAY AFTERNOON/EVENING WITH COLD FRONT OVER THE NORTHERN PLAINS NOT IMPACTING CENTRAL IL TAF SITES UNTIL LATER MONDAY NIGHT INTO TUE. LIGHT AND VARIABLE WINDS OVERNIGHT TO BECOME SW 4-7 KTS AFTER 15Z/MON AND LIGHT SSW BY SUNSET MON EVENING. 07 && .PREV DISCUSSION... ISSUED 239 PM CDT SUN JUL 21 2013 MAIN CONCERNS THIS PACKAGE WILL CONTINUE TO BE PCPN CHANCES FOR THE SHORT TERM AND THEN PCPN CHANCES AGAIN AT THE END OF THE WEEK AND INTO THE WEEKEND...IN THE LONG TERM PERIOD. MODELS SHOW GOOD AGREEMENT WITH KEEPING THE MID LEVEL NORTHWEST FLOW IN PLACE...WITH A RIDGE BUILDING OUT OVER THE ROCKIE MOUNTAIN REGION...ALL THROUGH MID WEEK. THE NORTHWEST FLOW WILL ALSO CONTINUE INTO THE EXTENDED PERIOD AND MODELS LOOK OK HERE TOO UNTIL LATE IN THE WEEK AND THE WEEKEND. ECMWF APPEARS TO BE STRONGER WITH A MID LEVEL SYSTEM COMING DOWN INTO THE AREA DURING THE END OF THE PERIOD. SHORT TERM...TONIGHT THROUGH WEDNESDAY FRONTAL SYSTEM OVER THE AREA THIS AFTERNOON WILL GRADUALLY WASHOUT TONIGHT THROUGH TOMORROW AS A STRONGER WEATHER SYSTEM DEVELOPS OUT IN THE PLAINS. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS THE ENTIRE CWA THIS EVENING AND THEN IN THE EAST AFTER MIDNIGHT...WITH CHANCES BACK TO THE WEST. LIGHT SHOWERS ARE ONGOING BUT REMNANTS OF AN MCS IN IOWA HAVE CONTINUED TO GET STRONGER IN SOUTH CENTRAL IOWA AND WILL MOVE EAST-SOUTHEAST INTO THE CWA THIS EVENING AND THROUGH TONIGHT. BELIEVE THIS LINE/COMPLEX OF STORMS WILL FOLLOW THE STATIONARY BOUNDARY OVER THE AREA AS IT MOVES EAST-SOUTHEAST. VARIOUS SHORT TERM MODELS FORECAST THIS AREA OF STORMS EAST AND SOUTHEAST INTO CENTRAL ILLINOIS THIS EVENING...THEREFORE CONFIDENCE IS HIGH ENOUGH FOR LIKELY POPS. NO SEVERE IS EXPECTED WITH THESE STORMS...BUT LOCALLY HEAVY RAINFALL AND DEADLY LIGHTNING WILL BE LIKELY. PCPN WILL DIMINISH TOMORROW...BUT WITH LOTS OF LOW LEVEL MOISTURE AND A STATIONARY BOUNDARY IN THE AREA...CANT RULE OUT A CHANCE OF THUNDERSTORMS SOMEWHERE TOMORROW. PCPN CHANCES WILL CONTINUE AND INCREASE INTO TOMORROW NIGHT AND TUESDAY AS ANOTHER...STRONGER FRONT PUSHES INTO AND THROUGH THE AREA. FORECAST FOR THIS FRONT APPEAR TO BE THAT IT WILL PUSH SHOULD OF THE STATE LATE TUE NIGHT AND THEN BRING DRIER AND LESS HUMID AIR INTO THE REGION FOR WEDNESDAY. APPEARS TEMPS WILL BE QUITE WARM ONE MORE DAY TOMORROW. THEN ADDITIONAL CLOUD COVER AND PCPN WILL CAUSE TEMPS TO BE SLIGHTLY COOLER FOR TUESDAY. MUCH COOLER TEMPS ARE THEN EXPECTED AFTER THE FRONT MOVES THROUGH THE AREA FOR WEDNESDAY. LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY DRY WEATHER WILL CONTINUE THROUGH THUR NIGHT AS NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA. A STRONGER SYSTEM/SHORT WAVE TROUGH WILL THEN DEVELOP AND MOVE TOWARD THE AREA FOR LATE IN THE WEEK. ECMWF IS STRONGER AND LOOKS MORE CONSISTENT FROM PREVIOUS RUNS WITH THIS NEXT SYSTEM...THAN THE GFS. LEANING TOWARD THE ECMWF MODEL GIVES A FORECAST OF PCPN CHANCES FOR FRIDAY THROUGH SATURDAY NIGHT...SOMEWHERE IN THE CWA...THEN DRY WEATHER POSSIBLE SUNDAY. STILL LOTS OF UNCERTAINTY WITH THIS PERIOD OF THE FORECAST SO WOULD NOT BE SURPRISED TO SEE CHANGES TO IT OVER THE NEXT SEVERAL DAYS. TEMPS SHOULD BE COOLER THAN LAST WEEK GIVEN THE NORTHWEST FLOW AND WENT COOLER THAN GUIDANCE FOR SAT AND SUNDAY. AUTEN && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
318 AM EDT MON JUL 22 2013 .SHORT TERM (Today through Tuesday)... Issued at 315 AM EDT Sun Jul 21 2013 Pronounced shortwave trough, centered now along the northern MO/IL border will move into our region today. Combined with a tropical airmass in place, and we should see another round of showers and storms this morning into the afternoon. Seeing one line of storms forming over the MO/AR border into western KY and another one closer to a stationary front to our north, along the central IL/IN border. With additional storms in the forecast, have decided to lift a flash flood watch for a portion of our forecast area. The Bluegrass has the lowest flash flood guidance, with 3-hour guidance between 1.5 and 2 inches. Areal average QPF for that region is around an inch, but it easily could be higher with any slow-moving heavy storms. Airmass looks too tropical for severe weather, though we do look to have a weak low moving up the Ohio Valley ahead of the upper level feature, so will have to watch for some rotation in any storms that form. We should see a break in the precip tonight, but the airmass does not dry out until after this period, so cannot rule out additional isolated storms. Another wave looks to come across the area Tuesday, bringing enhanced rain chances once more. Coverage should be more limited than today, but soundings favor a better chance for stronger storms, with gusty winds and hail as the main threats. Temperatures today will depend on how quick the precip exits our region this afternoon. Have gone with higher values over the west, mid 80s compared with around 80 for the east. Temperatures tonight should be similar to this morning, with no real change in airmass. Readings should warm back into the upper 80s for Tuesday. .LONG TERM (Tuesday Night through Sunday)... Issued at 300 AM EDT Mon Jul 22 2013 Longwave 500mb upper air pattern early Wednesday will feature a broad ridge centered over the Intermountain West and a robust trough centered over the Great Lakes. Northwest flow will influence the Lower Ohio Valley. Ultimately, this pattern will bring pleasant, seasonably cool weather and relatively low dewpoints, especially for the period Wednesday through Friday. Several weak waves may move southeast across the Lower Ohio Valley Tuesday through Saturday. The first will cross the Ohio River Tuesday evening. High pressure over the upper midwest will build in behind a cold front that will move across the Commonwealth during the early morning hours Wednesday. Scattered convection will likely end from the north to the south during the morning hours Wednesday as drier air arrives from the northwest. Think that Wednesday afternoon will stay dry with noticeably less humid conditions. Northwesterly winds behind this front will lower dewpoints into the upper 50s by Wednesday evening. High pressure will build across the northern Ohio Valley Thursday and continue through Friday. Expect mostly clear skies with comfortable nights. Highs will stay in the mid 80s with lows well down into the 60s. The proximity of the surface high to our north will lead to light northeasterly to easterly winds through early Saturday. For several days now, long range guidance has advertised a quick return of moisture ahead of an upper wave on Saturday. Showers and storms may approach as early as Saturday morning and continue during the day Saturday just ahead of a progressive 500mb trough. Temperatures still will stay relatively mild Saturday and Sunday, with highs in the 80s and upper 60s at night. Expect clearing Sunday with dry conditions. && .AVIATION (06Z TAF Update)... Issued at 135 AM EDT Mon Jul 22 2013 Very moist atmosphere remains in place ahead of an upper level disturbance forecast to move through the region this afternoon. Have tried to time storms based on RAP forecasts for now, giving a brief lull to the sites early than more storms. That same moisture likely also will cause brief cig/vsby issues despite storm forecast. Rain chances should become more limited when that trough comes through so have kept in some VFR cigs by mid/late afternoon with no storms. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ036-037-041>043- 048-049-057. $$ Short Term.......RJS Long Term........JSD Aviation.........RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
201 AM EDT MON JUL 22 2013 .UPDATE... ISSUED AT 200 AM EDT MON JUL 22 2013 INGESTED THE LATEST OBSERVATIONAL DATA INTO THE FORECAST GRIDS TO ESTABLISH NEW TRENDS. OVERALL THE INHERITED FORECAST WAS IN GOOD SHAPE...HOWEVER...WILL BE ISSUING A QUICK UPDATE TO REMOVE SOME OUTDATED WORDING FROM THE ZONE FORECAST TEXT PRODUCT. UPDATE ISSUED AT 932 PM EDT SUN JUL 21 2013 TRAINING STORMS WERE STILL ONGOING OVER THE NORTHERN SECTION OF THE CWA AS WAS DISCUSSED IN THE PREVIOUS UPDATE. WENT AHEAD AND EXTENDED SCT POPS FOR THE NEXT COUPLE OF HOURS...MAINLY ALONG THE MOUNTAIN PARKWAY WHERE MAIN SHOWER ACTIVITY HAS BEEN LOCATED. LATEST RADAR TRENDS ARE SHOWING BEST SHOWER ACTIVITY DIMINISHING...BUT LOW END CHANCE POPS ARE STILL WARRANTED FOR ONGOING ACTIVITY AND POTENTIAL REDEVELOPMENT. EXCESS MOISTURE ACROSS THE NORTH AND EAST HAS LED TO FOG DEVELOPMENT AT THE NWS OFFICE. AS RAIN CONTINUES TO DIMINISH...EXPECT FOG TO PREVAIL THROUGH MUCH OF THE NIGHT BEFORE NEXT AREA OF WIDESPREAD SHOWERS AND THUNDERSTORMS MOVES IN BY EARLY MORNING. MADE THIS UPDATE TO THE WEATHER GRIDS AS WELL...ADDING FOG IN FOR VALLEYS MAINLY IN THE EASTERN CWA. UPDATE ISSUED AT 544 PM EDT SUN JUL 21 2013 A CONTINUED LINE OF SCT TRAINING STORMS EXTENDS ACROSS THE NORTHERN HALF OF THE CWA ALONG SOME WEAK HORIZONTAL BOUNDARY. PREVIOUS FORECAST HAD SHOWERS ENDING OVER THE NW...BUT SO LONG AS THIS BOUNDARY REMAINS IN PLACE...EXPECT ISOLATED TO SCT SHOWERS AND THUNDERSTORMS TO CONTINUE OVER THIS AREA FOR THE NEXT COUPLE HOURS. ALSO ADDED IN SOME ISOLATED POPS FOR SOME AREAS OVERNIGHT...MAINLY BEFORE MIDNIGHT...BASED ON LATEST HI RES MODEL RUNS AND CURRENT FORECAST TRENDS. ADDED CURRENT OBSERVATIONS INTO ONGOING FORECAST AS WELL. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 325 PM EDT SUN JUL 21 2013 MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST. GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING UP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 325 PM EDT SUN JUL 21 2013 THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED. HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG. IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS. SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL. A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE COOLER AIR REMAINS TO START THE NEW WORK WEEK. THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 200 AM EDT MON JUL 22 2013 CHALLENGING AVIATION FORECAST THIS TIME AROUND...WITH SEVERAL ISSUES TO CONSIDER. FIRST WILL BE THE EXTENT OF FOG AROUND THE FORECAST...AS WE ARE CURRENTLY EXPERIENCING A LULL IN SHOWER AND STORM ACTIVITY. SKIES AT TAF ISSUANCE WERE PARTLY CLOUDY WITH VERY LIGHT WINDS...SO SOME AREAS WILL BE EXPERIENCING FOG OVERNIGHT. JKL WILL BE THE MOST CHALLENGING DUE TO THE ELEVATION OF THE AIRPORT. WILL LIKELY SEE WILD FLUCTUATIONS IN CIGS AND VSBYS AT JKL UNTIL MORE WIDESPREAD SHOWERS AND STORMS MOVE ACROSS THE AREA LATER THIS MORNING. HAVE USED A TEMPO GROUP TO ADDRESS ANY POTENTIAL LIFR CONDITIONS...WITH IFR TO MVFR CONDITIONS OTHERWISE. WENT A BIT MORE OPTIMISTIC WITH LOZ AND SME GOING WITH MOSTLY MVFR CONDITIONS THROUGHOUT THE PERIOD. THE PERIOD FROM 10Z ON WILL FEATURE WIDESPREAD SHOWERS AND STORMS WITH THE POSSIBLILITY OF LOCALLY HEAVY RAINFALL. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...AR SHORT TERM...KAS LONG TERM...GREIF AVIATION...AR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
136 AM EDT MON JUL 22 2013 ...Updated Aviation Discussion... .FORECAST UPDATE... Issued at 840 PM EDT Sun Jul 21 2013 Two effective boundaries are forcing convection this evening, as we remain in a juicy environment ahead of an approaching upper impulse. Isolated to scattered storms are firing along and just south of the I-64 corridor, with one particularly vigorous cell that has produced torrential rain and wind gusts near 50 mph in the Louisville Metro. A more solid area of rain with a leading convective line has fired along a northward-moving boundary in western Kentucky, and is trying to spread into south central Kentucky. May continue to see development near Interstate 64 into late evening, especially as outflows interact with each other. Otherwise the storms to our west will spread into the area, with likely POPs looking like a good bet after midnight. Current zone forecast has this handled fairly well, but the point-and-click and matrices have been updated to hone the finer details of when and where it will rain the rest of this evening. && .SHORT TERM (Tonight through Monday Night)... Issued at 300 PM EDT Sun Jul 21 2013 The synoptic pattern this afternoon features a low-amplitude western ridge/eastern trough pattern, placing the Ohio Valley within northwest flow aloft. A rather potent shortwave trough (compared to past weeks) will be the main focus for convection through the short term period. Convection this afternoon has remained across southern Kentucky and Tennessee. In fact, a cold pool finally developed in the convection across southern KY, which raced into Tennessee and has since cut off much of the CWA from any thunderstorm activity. While a few thunderstorms may redevelop across the area yet this afternoon into the evening, think anything will remain rather isolated in the near term. The main focus of the period will come tonight into early Monday morning, as the aforementioned shortwave trough dives into the region. Guidance suggests quite a bit of moisture transport occurring in response to the approaching PV anomaly. A low-level jet, which has been absent as of late, will increase to 20-30 knots. PWATs will rise into the 2-2.25 inch range overnight, which is in the 99th percentile climatologically for this time of year. Additionally, warm cloud depths will rise to near 14,000 feet. Seriously considered going with a flash flood watch, but there are a few mitigating factors. Slightly better tropospheric flow (500mb wind speeds will increase to 20-30 knots) will favor quicker storm motions than we`ve seen of late. Additionally, it`s tough to say which mesoscale boundaries will focus convection, and whether the orientation of any of these boundaries will favor training. Therefore, after coordination with surrounding offices, will hold off on one for now, but will advise the evening shift of the situation. Despite better flow aloft, the highly saturated atmospheric profiles will limit any severe potential due to a lack of instability and dry air aiding in downdraft potential. Therefore, expect the main threats to be torrential rain and lightning. The lead shortwave trough will push through by late Monday morning. How the overnight convection plays out will largely factor into the afternoon prospects for convection as the trough axis slides through. Think that many areas will likely be worked over, so don`t think coverage tomorrow afternoon into the evening will be all that impressive. Nevertheless, as the trough axis swings through, additional convection will likely develop, with the most favored areas being east of Interstate 65. Drier air and subsidence behind the wave should really diminish coverage Monday night. Will carry only chance to slight chance pops, which may still be too generous especially across southern Indiana and northern KY, which have good prospects of staying dry. Temperatures through the short term period will be highly dependent on convection. Therefore, went with a general blend of guidance, which puts lows tonight and tomorrow in the lower 70s, with highs Monday in the middle 80s. .LONG TERM (Tuesday through Sunday)... Issued at 238 PM EDT Sun Jul 21 2013 A cool front will approach from the northwest Tuesday and move through the region Tuesday night. The best mid and upper dynamics will be along and west of the Wabash Valley Tuesday, but we could still see some strong to locally severe storms Tuesday evening west and northwest of Louisville. Also, PWATs are only slightly elevated so widespread heavy rain isn`t expected but locally heavy downpours will certainly be possible. How fast the front moves through and how far it gets south of Kentucky will determine our chances for convection on Wednesday. It does appear that high pressure to our north will wait until Wednesday night to really push in, so will go along with neighboring offices and hold on to a small low confidence PoP on Wednesday, especially south. High pressure from the Great Lakes will be in control for the second half of the work week, keeping us dry. The models have been flaky regarding this weekend`s weather. The general sense, though, is that some sort of storm system will be coming in from the west giving a chance of showers and thunderstorms. We`ll have typical summer temperatures this week with highs in the 80s and lows in the 60s (a little warmer in urban Louisville). && .AVIATION (06Z TAF Update)... Issued at 135 AM EDT Mon Jul 22 2013 Very moist atmosphere remains in place ahead of an upper level disturbance forecast to move through the region this afternoon. Have tried to time storms based on RAP forecasts for now, giving a brief lull to the sites early than more storms. That same moisture likely also will cause brief cig/vsby issues despite storm forecast. Rain chances should become more limited when that trough comes through so have kept in some VFR cigs by mid/late afternoon with no storms. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........RJS Short Term.......KD Long Term........13 Aviation.........RJS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1233 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 1233 AM CDT MON JUL 22 2013 UPDATED AVIATION SECTION ONLY. && UPDATE... ISSUED AT 456 PM CDT SUN JUL 21 2013 AFTER LOOKING AT NEW HRRR MODEL REFLECTIVITY DATA AND 18Z NAM...IT APPEARS HEAVY RAIN IS MORE LIKELY IN SW INDIANA...SE ILLINOIS...AND NW KENTUCKY LATE TONIGHT INTO EARLY MONDAY. 850 MB LOW LEVEL FLOW IS FORECAST TO STRENGTHEN TO AROUND 20 KNOTS...WITH STRONG INDICATIONS OF A BACKBUILDING MCS. RAISED POPS FOR THE OVERNIGHT HOURS TO CATEGORICAL OR LIKELY IN NE COUNTIES. THE ENSEMBLE MEANS OF THE SREF AND GFS ALSO SHOW QPF BULLSEYES IN THAT AREA OVERNIGHT. SURFACE TO 850 MB CONVERGENCE AXIS IS FORECAST TO BE IN THAT AREA WITH A 500 MB SHORTWAVE TROUGH JUST UPSTREAM. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... ISSUED AT 215 PM CDT SUN JUL 21 2013 MAIN FORECAST CONCERN TONIGHT IS HEAVY RAIN POTENTIAL. LOTS OF MOISTURE AND INSTABILITY IS IN PLACE...ALONG WITH A BROAD AREA OF WEAK LIFT. THE PRIMARY LIFTING MECHANISM IS A 500 MB SHORTWAVE ADVANCING EAST/SOUTHEAST ACROSS CENTRAL MISSOURI. CONVECTION HAS BEEN SLOWLY INCREASING THIS AFTERNOON ALONG AND SOUTH OF A WEAK WARM FRONT THAT EXTENDS FROM THE LOWER OHIO VALLEY TO NORTHWEST ARKANSAS. THE STORMS WILL CONTINUE TO INCREASE THROUGH THE EARLY EVENING HOURS...AIDED BY THE APPROACHING SHORTWAVE AND WARM FRONTAL CONVERGENCE. WILL MENTION HEAVY RAIN IN GRIDS AND ZONES. LOW LEVEL WIND SPEEDS ARE CURRENTLY A LITTLE LOWER THAN OPTIMUM FOR AN ORGANIZED FLOODING THREAT. HOWEVER...RAP MODEL RUNS INDICATE SOME INCREASE AND BACKING OF LOW LEVEL WINDS LATE TODAY AND THIS EVENING. POTENTIAL FOR EXCESSIVE RAINFALL AND LOCAL FLOODING WILL NEED TO BE MONITORED THROUGH EVENING. LATER TONIGHT AND MONDAY MORNING...WEAKENING INSTABILITY AND DECREASING UPPER SUPPORT SHOULD BRING A GRADUAL DECREASE IN COVERAGE AND INTENSITY OF THE PRECIP. TEMPS ON MONDAY WILL DEPEND ON TIMING OF PARTIAL CLEARING...WHICH SHOULD TAKE PLACE FROM WEST TO EAST AS THE DAY GOES ON. WILL CONTINUE WITH PREVIOUS FORECASTS THAT ARE CLOSER TO GFS MOS THAN THE COOLER NAM MOS. A RELATIVE LULL IN PRECIP CHANCES IS EXPECTED MONDAY NIGHT. ON TUESDAY...A COLD FRONT WILL MOVE SOUTHEAST INTO SOUTHERN ILLINOIS AND SE MISSOURI BY LATE IN THE DAY. THE FRONT SHOULD ARRIVE DURING PEAK HEATING AND INSTABILITY...SO WILL CONTINUE WITH POPS ABOVE MOS GUIDANCE. PRECIP WATER VALUES WILL BE SOMEWHAT LOWER DUE TO A MORE VEERED /WEST TO NORTHWEST/ DEEP LAYER FLOW...WHICH IS WHY POPS WILL BE KEPT BELOW THE LIKELY CATEGORY. FLOW FIELDS WILL BE SOMEWHAT STRONGER WITH THIS SYSTEM...SO THE POTENTIAL FOR ISOLATED SEVERE STORMS EXISTS. CONVECTION SHOULD DIMINISH WITH THE PASSAGE OF THE COLD FRONT ACROSS THE LOWER OHIO VALLEY LATE TUESDAY NIGHT. .LONG TERM /WEDNESDAY THROUGH SUNDAY/... ISSUED AT 215 PM CDT SUN JUL 21 2013 THE MODELS ARE IN GENERAL AGREEMENT WITH FRONT ALONG OUR SOUTHERN BORDER BY 12Z WED. HOWEVER THE GFS AND THE NAM PUSH IT ON THROUGH LIMITING ANY PRECIP CHC AFTER 12Z WED. THE 00Z SUNDAY ECMWF LINGERS PRECIP OVER THE AREA ALL DAY WED. CURRENT GRIDS REFLECT HIGHEST PROB WOULD BE OVER SEMO AND LATEST RUNS SUPPORT THAT. HOWEVER WILL TRY TO LOWER POPS NORTH AND EAST AS PREVIOUS SHIFT DID AND CONTINUE THE TREND TOWARD A DRIER WED. IF THE 12Z ECMWF FOLLOWS THAT TREND THE MID SHIFT WILL BE ABLE TO BETTER DEFINE THE CHC. SO THIS TIME FRAME REMAINS A LITTLE SUSPECT FOR NOW WITH EITHER NORTH WINDS VIA NAM GFS OR STALLED FRONT ECMWF. THE 12Z UKMET SHOWS THE FRONT ALONG THE SOUTHERN BORDER AS WELL BUT THE RUN ENDS AT 12Z BUT APPEARS TO FAVOR THE WETTER ECMWF. FOR THE LATE WEEK CHC THE THE GFS BRINGS A FRONT THROUGH BUT THE ECMWF AND DGEX BRING AN MCS OUT OF THE CENTRAL PLAINS FRIDAY WITH A COLD FRONT IN ITS WAKE SATURDAY. THE GFS IS A LITTLE VOID OF THE MCS FEATURE AND WILL LEAN TOWARD THE ECMWF AND DGEX SOLUTION...BUT USE THE SLOWER TIMING OF THE ECMWF FOR THIS FEATURE. WILL MAINTAIN A SLGT CHC SAT NGT IN THE EAST. WILL KEEP SUNDAY DRY WITH MUCH COOLER AND DRIER AIR COMING INTO THE REGION. AS FOR TEMPS IF THE EXTENDED INIT COMES TO FRUITION IT WILL BE A MUCH COOLER AND WE COULD SEE SOME RECORD OR NEAR RECORD COOL TEMPS EARLY NEXT WEEK. THE OPPOSITE OF LAST SUMMER RECORD SETTING HEAT. && .AVIATION... ISSUED AT 1233 AM CDT MON JUL 22 2013 WITH THE EXCEPTION OF SOME SHORT-LIVED IFR CIGS IN SWRN IND...CIGS SHOULD BE VFR/MVFR OUTSIDE OF TSTM ACTIVITY...WHICH IS EXPECTED TO OCCUR AT THE FOUR TAF SITES PRIMARILY BETWEEN ABOUT 06Z IN THE WEST TO AS LATE AS 13Z IN THE EAST AS UPPER LEVEL ENERGY MOVES THROUGH. WINDS WILL BE QUITE VARIABLE OVERNIGHT...BUT SHOULD SETTLE INTO A SWRLY DIRECTION AFTER SUNRISE. EXPECT IMPROVING CONDITIONS AS THE DAY GOES ON. MVFR VSBYS DUE TO FOG/RAIN SHOULD BE COMMON OUTSIDE TSTMS OVERNIGHT. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...MY SHORT TERM...MY LONG TERM...KH AVIATION...DB
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
256 AM EDT MON JUL 22 2013 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST DURING THE EARLY PORTION OF THIS WEEK...AS A COLD FRONT BECOMES NEARLY STATIONARY FROM THE OHIO VALLEY TO THE NORTHERN MID ATLANTIC STATES. MEANWHILE...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL PERSIST ACROSS THE REGION. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... LATEST WX ANALYSIS SHOWS WEAKENING SFC FRONT FROM JUST SOUTH OF LONG ISLAND NY...EXTENDING W-SW BACK INTO THE OHIO AND MIDDLE MISSOURI VALLEYS. BULK OF CONVECTION WHICH ERUPTED ALONG SFC TROUGH...AND DUMPED BETWEEN 3 AND 5 INCHES OVER PARTS OF THE PIEDMONT AND MIDDLE PENINSULA EARLIER THIS EVENING...HAVE GREATLY DIMINISHED IN INTENSITY AND AREAL CVG WITH LOSS OF HEATING AND AS NOCTURNAL STABILITY SETS IN. HRRR HAS HANDLED TRENDS RATHER WELL THIS EVENING AND HV CONTINUED TO LEAN IN ITS DIRECTION OVERNIGHT. OVERALL, WHILE INSTABILITY AND SYNOPTIC SCALE FORCING WANE SIGNIFICANTLY OVERNIGHT, WEAK LLVL CONVERGENCE ALONG THE TROUGH AXIS PERSISTS. THUS, WILL RETAIN A SLIGHT CHC/LOW CHC POP FOR AN ISO TO WIDELY SCT SHRA AFTER MIDNIGHT. ANOTHER WARM AND HUMID OVERNIGHT IS EXPECTED WITH LOWS IN THE LOW/MID 70S...UNDER A PARTLY TO MOSTLY CLOUDY SKY. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... THE OVERALL PATTERN REMAINS UNSETTLED MONDAY AS A SURFACE BOUNDARY/WEAK LOW STALL OVER THE AREA. ADDITIONALLY...A VIGOROUS TROUGH CARVES OVER THE GREAT LAKES. A LEADING SHORTWAVE EJECTS OUT OF THE TROUGH ACROSS THE OHIO VALLEY TOWARD THE APPALACHIANS MONDAY AFTERNOON/EVENING. HENCE...HIGH CHANCE/LOW-END LIKELY POPS ARE FORECAST MONDAY AFTN/EVENING. AFTERNOON HIGHS WILL TREND DOWN SLIGHTLY DUE TO INCREASED CLOUD COVER AND A HIGHER PROBABILITY OF SHOWERS/TSTMS (AND SHIFTING WIND DIRECTION MAINLY N)...ALTHOUGH DEWPOINTS WILL REMAIN IN THE LOW/MID 70S. HIGHS SHOULD RANGE FROM THE MID/UPPER 80S TO AROUND 90 MONDAY. ANY SEVERE THREAT LOOKS RATHER LIMITED MONDAY...WITH THE MAIN CONCERN AGAIN BEING HEAVY RAIN FROM SLOW MOVING STORMS. THE PARENT TROUGH PIVOTS N OF THE GREAT LAKES TUESDAY AS A SECONDARY WAVE LIFTS ACROSS THE MID ATLANTIC. THE LATEST DATA BRINGS THE WAVE THROUGH EARLIER IN THE DAY...FOLLOWED BY WESTERLY MID-LEVEL FLOW BY LATER AFTERNOON. GIVEN THIS...POPS HAVE BEEN LOWERED...ESPECIALLY W. HOWEVER..A WELL-DEFINED LEE SIDE TROUGH REMAINS OVER THE AREA...SO WILL MAINTAIN 30 POPS W...TO 40 E. HIGHS SHOULD AVERAGE IN THE UPPER 80S TO LOW 90S. THE 21/12Z GFS/NAM BRING YET ANOTHER SHORTWAVE TROUGH THROUGH THE REGION WEDNESDAY. THE MAIN MOISTURE FEED MAY BE WELL OFF THE COAST BY THIS TIME...SO WILL GO NO HIGHER THAN CHANCE POPS AT THIS TIME. HIGHS SHOULD AGAIN RANGE FROM THE UPPER 80S TO LOW 90S. LOWS THROUGH THE PERIOD SHOULD RANGE FROM 70-75. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... UPR TROF OVR THE ERN THIRD OF THE U.S. WED NGT THRU THU...WILL SHIFT EWRD AND OFFSHR THU NGT THRU FRI. THIS WILL PUSH FRNTL BNDRY ALNG OR JUST OFFSHR AT THE BEGINNING OF THE PERIOD...FARTHER OUT TO SEA. WEAK HI PRES WILL BLD INTO AND OVR THE AREA FOR FRI NGT INTO SAT. THEN...ANOTHER SHRTWV TROF AND ASSOCIATED COLD FRONT WILL APPROACH AND MOVE INTO THE REGION LATE SAT NGT THRU SUN. AT THIS TIME...WILL NOT BE GOING ANY HIGHER THAN 20% OR 30% THRU THE PERIOD...DUE TO LOW CONFIDENCE OF COVERAGE. MIN TEMPS WILL BE IN THE UPR 60S TO MID 70S THU MORNG...AND MAINLY IN THE MID 60S TO LWR 70S FRI...SAT AND SUN MORNGS. MAX TEMPS WILL GENERALLY BE IN THE MID TO UPR 80S THRU THE PERIOD. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... LGT AND VRB WNDS THIS MRNG WITH A WEAK TROF OF LO PRES IN THE VICINITY. LO-LVL MOISTURE TRAPPED UNDER A WEAK INVERSION WILL LEAD TO LIFR CONDS OVER RIC FOR AT LEAST THE NEXT 6 HR...WITH MVFR VSBYS FOR SBY...AND VFR ELSEWHERE WHERE TEMP/DEWPT SPREADS ARE LARGER. FOR DAYTIME TDY...AS WITH YESTERDAY EXPECT SCT AFTN/EVENG SHRAS/TSTMS. THUNDER PSBL AS WELL BUT KEPT OUT OF THE TAFS FOR NOW DUE TO UNCERTAINTIES SUCH AS TIMING. VSBY/CIG REDUCTIONS LIKELY IN HEAVIER SHRAS/TSTMS. LO CLDS MAY PERSIST FOLLOWING THE RAIN TNGT ALONGSIDE DIMINISHING WINDS WITH THE FRNTAL BNDRY IN THE VICINITY. OUTLOOK...SCT MAINLY AFTN AND EARLY EVENING TSTMS CAN BE EXPECTED TUE THROUGH FRI. AVIATION CONDS MAY LWR BRIEFLY IN HEAVIER PCPN. PATCHY IFR FOG NEAR SUNRISE CANNOT BE RULED BUT NO WIDESPREAD IFR IS INDICATED. && .MARINE... SUB-SCA CONDS WILL PREVAIL OVER THE NEXT SEVERAL DAYS OVER AREA WATERS. SWELLS WILL IMPACT THE COASTAL WATERS DUE TO STRONGER WINDS ASSOCIATED WITH THE BERMUDA HIGH WELL OFF THE COAST. ADDED SOME HEIGHT TO THE SEAS DUE TO THE SWELL...ESPECIALLY MONDAY NIGHT AND EARLY TUESDAY...BUT KEPT THEM BELOW 5 FT FOR OUR COASTAL ZONES. EXPECT LOCALLY STRONGER WNDS IN SHOWERS AND TSTMS THRU THE PERIOD. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ/LKB NEAR TERM...MAM SHORT TERM...AJZ/LKB LONG TERM...TMG AVIATION...MAS/JEF MARINE...LSA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
457 AM EDT MON JUL 22 2013 .SYNOPSIS... ISSUED AT 407 AM EDT MON JUL 22 2013 HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO NORTHERN MICHIGAN. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 407 AM EDT MON JUL 22 2013 INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT. OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF 07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE OF LAKE MICHIGAN. CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN. THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z. INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY AREAS. THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z. BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD 1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE BOUNDARY. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON JUL 22 2013 THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF THE NEXT WORK WEEK. TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD. TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW WISCONSIN. THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE. TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT. REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND LOWER 70S FOR THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 216 AM EDT MON JUL 22 2013 RETURN SOUTHERLY FLOW ON THE BACKSIDE OF THE SURFACE HIGH WILL ALLOW LOW/MID LEVEL CLOUDS TO MOVE INTO AND/OR DEVELOP ACROSS NORTHERN LOWER MICHIGAN THE REST OF THE NIGHT AND INTO THE AFTERNOON HOURS. HEATING OF THE DAY SHOULD ALSO HELP FIRE OFF A FEW SHOWERS AND THUNDERSTORMS...MOST LIKELY TO IMPACT PLN AND APN AWAY FROM THE STABILIZING INFLUENCES OF LAKE MICHIGAN. A COLD WILL APPROACH THE AREA THROUGH THE LATE EVENING AND OVERNIGHT HOURS...GIVING BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND STORMS. OVERALL...VFR CONDITIONS WILL BE THE RULE...THOUGH OF COURSE...LOCALIZED WORSE CONDITIONS ARE ALWAYS POSSIBLE NEAR ANY THUNDERSTORMS. LIGHT SOUTHEAST WINDS THROUGH SUNRISE WILL GIVE WAY TO SOME GUSTY SOUTHWEST CONDITIONS THROUGH THE DAY...WITH GUSTS OF 15-20 KNOTS POSSIBLE. LOW LEVEL WIND SHEAR WILL BECOME AN ISSUE TOWARD SUNSET. && .MARINE... ISSUED AT 407 AM EDT MON JUL 22 2013 LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS. THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED. HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK... GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH THURSDAY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ SYNOPSIS...SD SHORT TERM...DL LONG TERM...SD AVIATION...LAWRENCE MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 AM EDT MON JUL 22 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 410 PM EDT SUN JUL 21 2013 WV IMAGERY AND RUC ANALYSIS INDICATED MID/UPPER LEVEL LOWS OVER NE CANADA AND NRN BC RESULTING IN ZONAL TO WNW FLOW OVER SRN CANADA AND THE NRN CONUS. AN AREA OF CONVECTION HAS PERSISTED AHEAD OF PROMINENT SHORTWAVE TROUGH LOCATED OVER SRN SASK. THE COMBINATION OF A WEAK SHRTWV AND WAA AHEAD OF A WARM FRONT OVER IA SUPPORTED ANOTHER AREA OF SHRA/TSRA OVER CNTRL/SRN WI. TONIGHT...RADAR AND SHORT RANGE MODELS SUGGEST THAT ANY SHRA/TSRA ASSOCIATED WITH THE WI SHRTWV WILL NOT IMPACT THE CWA THIS EVENING. LINEAR EXTRAPOLATION OF THE SASK SHRTWV AND CONVECTION MOVING INTO THE SW CORNER OF MANITOBA WOULD BRING THE PCPN WITH THIS FEATURE INTO WRN UPPER MI BTWN 09Z-11Z. HOWEVER...AS THIS FEATURE MOVES INTO THE AIRMASS OVER THE NRN LAKES AND AWAY FROM THE MORE FAVORABLE MUCAPE OVER NRN MN...EXPECT THAT THE CONVECTION WILL WEAKEN. SO...THE FCST ONLY MENTIONS CHANCE POPS WITH ISOLD TS POSSIBLE OVERNIGHT. MONDAY...AFTER THE INITIAL BATCH OF SHRA/TSRA MOVES THROUGH MAINLY THE NW CWA EARLY MONDAY...THE FORECAST BECOMES MORE UNCERTAIN. THE AMOUNT OF DAYTIME WARMING AND RESULTING INSTABILITY WILL BE IMPACTED BY LINGERING CLOUD COVER IN THE WAA REGIME. IF THE CLOUDS BREAK UP ENOUGH AND TEMPS CLIMB TO AROUND 80 AS FCST WITH DEWPOINTS LOWER 60S...MLCAPE VALUES WOULD PUSH INTO THE 1000-1500 J/KG RANGE. STRONG LOW LEVEL AND A VEERING WIND PROFILE IS EXPECTED WITH 0-6KM BULK SHEAR TO AROUND 40 KT WITH CURVED HODOGRAPHS. THAT AMOUNT OF INSTABILITY COMBINED WITH A FAVORABLE SHEAR PROFILE WOULD SUPPORT POTENTIAL FOR SEVERE STORMS INCLUDING ISOLATED SUPERCELLS. THE MAIN TRIGGER FOR CONVECTION WOULD BE THE LIMITED FORCING WITH THE NRN ONTARIO SHRTWV TAIL ALONG WITH A PREFRONTAL TROUGH AND LAKE BREEZE BOUNDARIES AHEAD OF THE MAIN COLD FRONT MOVING INTO THE AREA DURING THE EVENING. HOWEVER...THE SEVERE WEATHER THREAT WILL BE CONDITIONAL...DEPENDENT ON THE AMOUNT OF INSTABILITY THAT DEVELOPS. THE GREATEST CHANCE FOR HIGHER CAPE VALUES IS EXPECTED NEAR THE WI BORDER FROM IWD-IMT IN LINE WITH SPC SREF SVR CALIBRATED PROB AND SPC OUTLOOK. THERE IS ALSO SOME UNCERTAINTY WITH TIMING...BUT THE GREATEST CHANCES WOULD LIKELY FROM W INTO CNTRL UPPER MI. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 449 AM EDT MON JUL 22 2013 TUESDAY...THE CWA WILL BE BETWEEN A DEPARTING SFC LOW NEAR JAMES BAY AND A SFC HIGH OVER NW MN AT 12Z. THE TIGHT PRESSURE BETWEEN THE SYSTEM AND BEHIND THE COLD FRONT THAT MOVED THROUGH MON EVENING/NIGHT WILL LEAD TO GUSTY NLY WINDS...BUT THE GRADIENT AND WINDS WILL DECREASE LATE IN THE DAY. BECAUSE OF THE GUSTY WINDS...WAVES WILL INCREASE AND ASSOCIATED SWIM RISK WILL BE HIGH. TEMPS WILL BE COOLER THAN TODAY...WITH HIGHS IN THE 60S NEAR LAKE SUPERIOR TO AROUND 70 WELL INLAND. TUESDAY NIGHT...TEMPS WILL FALL TO OR BELOW 40F OVER PARTS OF THE INTERIOR W DUE TO CLEAR SKIS AND CALM WINDS. WEDNESDAY...INCLUDED SLIGHT POPS IN THE AFTERNOON AS MODELS CONTINUE TO INDICATE A CONVECTIVELY INDUCED SHORTWAVE MOVING THROUGH NRN WI. NOT TOO SURE ABOUT WHAT WILL END UP HAPPENING WITH THE SHORTWAVE...BUT THOUGHT IT WAS WORTH THE SLIGHT POPS. TEMPS WILL BE A BIT WARMER THAN TUESDAY...WITH HIGHS IN THE MID 60S NEAR LAKE SUPERIOR TO THE MID 70S INLAND. UNCERTAINTY INCREASES ON A DAILY BASIS WED NIGHT THROUGH SUN AS MODELS BRING MULTIPLE ROUNDS OF UPPER LEVEL ENERGY INTO THE REGION...BUT DIFFER SIGNIFICANTLY BETWEEN MODELS AND BETWEEN RUNS ON THE STRENGTH/PLACEMENT OF THAT ENERGY...WHICH WILL PLAY A CRITICAL ROLE IN PRECIP CHANCES LATE IN THE WEEK AND INTO THE WEEKEND. WILL JUST GO WITH THE CONSENSUS GUIDANCE DUE TO THE UNCERTAINTY...BUT WILL NOT ALLOW POPS BE GET TOO HIGH. TEMPS ARE ALSO UNCERTAIN...BUT IT APPEARS A WARMER DAY WILL BE IN STORE FOR THU...WITH COOLING CONDITIONS FRIDAY INTO THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 248 AM EDT MON JUL 22 2013 VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE PERIOD. EXPECT INCREASING MID CLOUDS LATE TONIGHT INTO MONDAY MORNING AHEAD OF AN APPROACHING DISTURBANCE. SOME SHRA ARE POSSIBLE AT ALL SITES MON MORNING AND TRIED TO TIME THESE WITH EITHER PROB30 GROUPS OR PREVAILING. FRONT COMES THROUGH BY EVENING AND SWITCHES THE WIND TO THE NORTHWEST. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 410 PM EDT SUN JUL 21 2013 SRLY WINDS WILL INCREASE TO AROUND 20 KNOTS LATE TONIGHT AND MONDAY AHEAD OF A LOW PRESSURE TROUGH MOVING THROUGH THE AREA. NORTH TO NORTHWEST WINDS WILL THEN INCREASE TO 20-25 KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND THE TROUGH/COLD FRONT MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN BELOW 20 KNOTS TUE NIGHT THROUGH THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
401 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT MON JUL 22 2013 EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE 22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY /MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35. CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT. HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 359 AM CDT MON JUL 22 2013 MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT. THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH SATURDAY. AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF THE BUNCH. FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE. ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH. IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE 22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE ABLE MAKE A RUN AT THAT RECORD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1152 PM CDT SUN JUL 21 2013 THUNDERSTORMS OVER THE DAKOTAS ARE INDEED WEAKENING AS EXPECTED... BUT A FEW SHOWERS MAY BE IN THE VICINITY OF AXN DURING THE FIRST SEVERAL HOURS OF THE TAF PERIOD. HAVE A HARD TIME SEEING THEM MAKING IT AS FAR EAST AS STC OR AS FAR SOUTH AS RWF. THE FRONT WILL LIKELY BECOME MORE ACTIVE AGAIN LATE MONDAY MORNING OVER ERN MN AND MONDAY AFTERNOON OVER WRN WI. CONTINUED THE PROB30S UNTIL FROPA WITH WINDS VEERING NORTHWEST AND INCREASING WITH GUSTS TO 20 KT UNTIL EARLY EVENING. KMSP...BIGGEST CONCERN CONTINUES TO BE WHETHER THE IFR CIGS OVER WRN WI CAN MAKE IT AS FAR WEST AS MSP EARLY MONDAY. CURRENT INDICATIONS ARE THAT THEY WILL NOT...BUT IT WILL BE CLOSE. CONTINUED SCT MVFR MENTION FOR NOW. /OUTLOOK FOR KMSP/ TUE...VFR. WINDS N 5 TO 10 KT. WED...VFR. MVFR WITH A CHANCE OF SHRA/TSRA LATE NIGHT. WINDS LGT AND VRB. THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS LGT AND VRB. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...MPG AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
431 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CDT MON JUL 22 2013 THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR FLOW. THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND 06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY THEN. THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST STORMS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND TEMPERATURES. MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A LITTLE DIFFERENT WITH EACH MODEL. THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE AREA. TEMPERATURES WILL BE COOLER THAN TODAY. A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY. TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME LINGERING THUNDERSTORMS. FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER SIDE DURING THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1246 AM CDT MON JUL 22 2013 WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS...BUT ANY THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE THE NORTHEAST. AM CALLING FOR VFR CONDITIONS THROUGHOUT THE PERIOD...BUT WILL HAVE TO WATCH OUT FOR SOME POSSIBLE LOW CLOUD DEVELOPMENT TO THE SOUTH OF KGRI THAT HAS A SLIM CHANCE OF IMPACTING KGRI. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
355 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 355 AM CDT MON JUL 22 2013 THUNDERSTORMS WILL MOVE EAST SOUTHEAST OUT OF THE FORECAST AREA THIS MORNING WITH CLEARING SKIES TO THE WEST. COOL FRONT OVER CENTRAL SOUTH DAKOTA IS PROGGED TO MOVE SOUTH ACROSS WESTERN NEBRASKA TODAY AND BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT THIS AFTERNOON OVER THE SOUTHEAST PORTION OF THE FORECAST AREA. TEMPERATURES SIMILAR TO YESTERDAYS WITH SOME UPPER 80S NORTH AND LOW 90S SOUTH. FOCUS THEN SHIFTS NORTH THROUGH THE EARLY MORNING HOURS OF TUESDAY WITH BOUNDARY LYING ACROSS WESTERN NEBRASKA AND WEAK WAVE MOVING THROUGH FAST NORTHWEST FLOW EXPECTED TO FIRE OFF SOME THUNDERSTORMS GENERALLY NORTH OF HIGHWAY 2 THROUGH THE EARLY MORNING. LOWS AROUND 60. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 355 AM CDT MON JUL 22 2013 MAIN FORECASTING CONCERN IN THE EXTENDED PERIODS CONTINUES TO BE PRECIPITATION CHANCES...ESPECIALLY SINCE TIMING AND LOCATIONAL DIFFERENCES REMAIN PROBLEMATIC GIVEN THE LOW RUN TO RUN CONSISTENCY IN THE SMALL AMPLITUDE PERTURBATIONS WITHIN NORTHWESTERLY FLOW. THE FIRST OF THESE WEAK PERTURBATIONS IS SHOWN TO CROSS THE NORTHERN/CENTRAL PLAINS TUESDAY INTO EARLY WEDNESDAY...BRINGING A SLIGHT CHANCE OF STORMS BACK TO THE AREA FROM NORTHWEST TO SOUTHEAST. PARAMETERS ARE NOT TOO FAVORABLE FOR SEVERE DEVELOPMENT AS SHEAR IS SUFFICIENT...BUT INSTABILITY IS SOMEWHAT LACKING. THEREAFTER...THE NEXT BEST SHOT AT WIDESPREAD PRECIPITATION COMES EARLY THURSDAY AS THE GFS AND EC LIFT A DECENT SHORTWAVE INTO SOUTHWESTERN/WESTERN NEBRASKA. FRONTAL SUPPORT REMAINS TO THE SOUTH AND WEST OF THE FORECAST AREA...WITH THE BEST INSTABILITY SOUTH AS WELL...HOWEVER BOTH MODELS GENERATE QPF ACROSS MUCH OF THE CWA AS MID TO UPPER TROPOSPHERIC COOLING ASSOCIATED WITH THE WAVE OCCURS. WILL LIMIT POPS IN THE 40 PERCENT RANGE FOR NOW AS STRONGEST FORCING IS REMOVED FROM THE CWA. THE ACTIVE NORTHWEST PATTERN CONTINUES INTO LATE WEEK/WEEKEND WITH ADDITIONAL WAVES BRINGING CONTINUED PRECIPITATION CHANCES TO THE AREA...BUT WITH ALL THE WAFFLING IN THE LONG RANGE PERIODS WILL LIMIT ALL POPS AT 25 PERCENT OR LESS BEYOND FRIDAY MORNING UNTIL TIMING AND LOCATIONAL DIFFERENCES ARE RESOLVED. AS FOR TEMPERATURES...THANKS TO EXPECTED CLOUDS...PRECIPITATION...AND EASTERLY TO SOUTHEASTERLY LOW LEVEL FLOW RECYCLED FROM COOL MIDWEST HIGH...HIGHS SHOULD FALL BACK INTO THE 80S FOR MOST LOCATIONS...ESPECIALLY THURSDAY AND BEYOND. THE WARMEST READINGS WILL ONCE AGAIN BE CONFINED TO OUR FAR WEST...IN CLOSER PROXIMITY TO A SOUTHWESTERN UPPER LEVEL RIDGE ON TUESDAY WITH LOWER 90S POSSIBLE. LOWS WILL REMAIN SEASONAL THROUGH THE EXTENDED PERIODS...WITH MAINLY 60S ANTICIPATED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1122 PM CDT SUN JUL 21 2013 THE LATEST CONSENSUS OF THE HRRR...NAM AND RAP MODELS SUGGESTS ISOLATED THUNDERSTORMS WOULD CONTINUE THROUGH ABOUT 12Z MONDAY MORNING AND THEN REDEVELOP BETWEEN 21Z-00Z MONDAY AFTERNOON. GIVEN THE STRONG CAP OPERATING MONDAY AFTN...JUST ISOLATED STORMS WOULD BE EXPECTED GENERALLY FROM KBBW WEST THROUGH KLBF...KIML AND KOGA. STORM ACTIVITY...IF IT DEVELOPS...WOULD EXIT THE FCST AREA BY ROUGHLY 03Z. A THIRD SOUTHEASTWARD MOVING AREA OF THUNDERSTORMS COULD THEN BEGIN AFFECTING NRN NEB AROUND 06Z MONDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...POWER LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
304 AM CDT MON JUL 22 2013 .DISCUSSION... PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35 KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING. SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED TUESDAY AS WELL. THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A SMALL PRECIP CHANCE SUNDAY INTO MONDAY. DEWALD && .AVIATION...06Z TAFS FOR KOMA...KOFK...KLNK SOME PATCHY FOG POSSIBLE MONDAY MORNING AT KOMA AND KLNK WITH LIGHT WINDS AND HIGH LOW LEVER MOISTURE. A COLD FRONT WILL PUSH ACROSS THE AREA WITH SOUTH/SOUTHWEST WINDS VEERING AROUND TO THE NORTHWEST WITH THE FRONT...AFTER 15Z AT KOFK MONDAY. SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG THE FRONT WITH GOOD MOISTURE AND INSTABILITY. FOR NOW INCLUDED A COUPLE OF HOURS WITH SHOWERS IN THE AFTERNOON AND EARLY EVENING AT KOMA AND KLNK AND CAN ADD TSRA WHEN THERE IS BETTER CONFIDENCE IN THE COVERAGE AND TIMING. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1126 PM CDT SUN JUL 21 2013 .SYNOPSIS... ISSUED AT 333 PM CDT SUN JUL 21 2013 H5 ANALYSIS FROM THIS MORNING...HAS TWO AREAS OF HIGH PRESSURE ALOFT...THE FIRST OVER NEVADA...AND A SECOND OFF THE CAROLINA COAST. IN BETWEEN...A TROUGH OF LOW PRESSURE EXTENDED ACROSS THE SRN PLAINS FROM KANSAS INTO NERN TX. ACROSS THE NRN TIER OF STATES...INCLUDING THE CENTRAL AND NRN PLAINS...BROAD WEST NORTHWESTERLY AND WESTERLY FLOW EXTENDED FROM THE PACIFIC NW...INTO THE CENTRAL AND NRN PLAINS...EWD INTO THE MID ATLANTIC AND NEW ENGLAND. UPSTREAM OF THE CENTRAL PLAINS...A DECENT SHORTWAVE WAS NOTED OVER SRN ALBERTA...AND A SECOND STRONGER WAVE OVER NWRN PORTIONS OF BRITISH COLUMBIA. AT THE SURFACE...A CONVECTIVE INDUCED MESO HIGH WAS LOCATED OVER SWRN NEBRASKA...WITH DECENT SRLY WINDS NOTED ACROSS THE PANHANDLE ATTM. AS OF 3 PM CDT...TEMPERATURES RANGED FROM 84 AT AINWSWORTH...TO 90 AT IMPERIAL. && .UPDATE... ISSUED AT 921 PM CDT SUN JUL 21 2013 THE HRRR SHOWS THE STORMS ACROSS NW NEB FILLING IN AND BECOMING A LINE OF TSTMS WHICH SWEEP THE FCST AREA OVERNIGHT. THIS IS PROBABLY OVERDONE. THE RAP SHOWS NO STORMS AT ALL BUT INDICATES A 20 TO 30 KT LOW LEVEL JET RUNNING DUE NORTH UP THROUGH WRN NEB TONIGHT. PWAT SHOULD INCREASE TO 1.25 INCHES AND MAYBE MORE ACCORDING TO THE RAP. SO THE FORECAST HAS BEEN UPDATED FOR SCATTERED TSTMS WHICH IS A COMPROMISE OF THE HRRR AND RAP MODELS. NOTE THE 18Z NAM SHOWED ISOLATED STORMS MOVING SOUTHEAST TONIGHT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 333 PM CDT SUN JUL 21 2013 WEAK WAVE IS MOVING ACROSS EAST CENTRAL WYOMING THIS AFTERNOON. THIS WAVE WILL BE THE FOCUS FOR SOME ISOLATED THUNDERSTORMS. LACKING SOME MOISTURE AS DEW PTS IN THE LOWER TO MID 50S. LOW LEVEL JET ALONG THE FRONT RANGE TONIGHT AND WILL AID IN THUNDERSTORM DEVELOPMENT. ATMOSPHERE TOOK A BEATING LAST NIGHT AND EARLY THIS MORNING...SO CONFIDENCE IS LOW ON HOW WIDESPREAD THE COVERAGE WILL BE...HOWEVER SEVERAL REMNANT BOUNDARIES COULD HELP TO SPARK DEVELOPMENT. SINCE THERE IS NOT MUCH OF A CU FIELD...AND ONLY ONE CELL HAS GOTTEN GOING OVER WYOMING...EXPECT COVERAGE TO BE ISOLD. AS FOR TEMPS...THEY SHOULD COOL BACK INTO THE 60S...ALTHOUGH LOCALLY IN THE WEST A BRIEF DIP BELOW 60 IS POSSIBLE. TOMORROW RIDGE REMAINS DOMINATE TO THE SOUTHWEST...WITH MOSTLY SUNNY SKIES THROUGH MOST OF THE DAY. HIGHS INTO THE LOWER/MID 90S ACROSS THE SW TO THE UPPER 80S ACROSS N CENTRAL. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 333 PM CDT SUN JUL 21 2013 MID RANGE...MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING CHALLENGE CONTINUES TO BE PRECIPITATION CHANCES...AS TIMING AND LOCATION REMAIN PROBLEMATIC GIVEN THE NORTHWESTERLY FLOW. FOR MONDAY NIGHT...MID LEVEL HTS WILL BEGIN TO INCREASE AS HIGH PRESSURE ALOFT BUILDS EAST OF THE DESERT SOUTHWEST. INCREASED MID LEVEL WAA WILL RESULT...LEADING TO INCREASED POPS MONDAY NIGHT INTO EARLY TUESDAY. WILL KEEP POPS AS SLIGHTS ATTM...AS DECENT JET SUPPORT IS FOCUSED EAST OF THE AREA. A SECONDARY AREA OF MID LEVEL WAA WILL TRACK ACROSS THE CWA FROM NW TO SE ON TUESDAY INTO TUESDAY EVENING. WILL HOLD ONTO SLIGHT CHANCES FOR PCPN SINCE THE BEST JET SUPPORT REMAINS EAST OF THE AREA. BY WEDNESDAY AFTERNOON...BOTH THE NAM AND GFS FORCE A DECENT SHORTWAVE INTO WRN NEBRASKA LATE IN THE DAY...LIFTING THIS EAST INTO WEDNESDAY NIGHT. WILL START POPS OFF LOW IN THE WEST...AS BETTER CHANCES WILL ARRIVE WEDNESDAY NIGHT AS THE FORECAST AREA IS IN THE RIGHT REAR QUAD OF THE EXITING JET. LONG RANGE...WEDNESDAY NIGHT THROUGH SUNDAY...ACTIVE WESTERLY AND NORTHWESTERLY FLOW ALOFT WILL CONTINUE ACROSS THE CENTRAL AND NORTHERN PLAINS INTO THE EXTENDED PERIODS. ATTM...THE BEST CHANCES FOR RAIN APPEAR TO LIE ON WEDNESDAY NIGHT AND FRIDAY NIGHT AS THE FORECAST AREA IS IN A FAVORABLE EXIT REGION OF THE H300 JET. HAVE INCREASED POPS INTO THE 50 PERCENT RANGE FOR WEDNESDAY NIGHT AND THURSDAY AND WILL KEEP CHANCE POPS GOING INTO THURSDAY NIGHT. THE EXTENSION OF POPS INTO THURSDAY NIGHT...IS TO ACCOMMODATE THE LATEST ECMWF WHICH IS 12 HRS SLOWER THAN THE LATEST GFS SOLN. TEMPERATURES FOR THE WEEK WILL COOL BACK INTO THE 80S...THANKS TO EXPECTED CLOUD COVER AND SERLY AND ERLY UPSLOPE WINDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1122 PM CDT SUN JUL 21 2013 THE LATEST CONSENSUS OF THE HRRR...NAM AND RAP MODELS SUGGESTS ISOLATED THUNDERSTORMS WOULD CONTINUE THROUGH ABOUT 12Z MONDAY MORNING AND THEN REDEVELOP BETWEEN 21Z-00Z MONDAY AFTERNOON. GIVEN THE STRONG CAP OPERATING MONDAY AFTN...JUST ISOLATED STORMS WOULD BE EXPECTED GENERALLY FROM KBBW WEST THROUGH KLBF...KIML AND KOGA. STORM ACTIVITY...IF IT DEVELOPS...WOULD EXIT THE FCST AREA BY ROUGHLY 03Z. A THIRD SOUTHEASTWARD MOVING AREA OF THUNDERSTORMS COULD THEN BEGIN AFFECTING NRN NEB AROUND 06Z MONDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...MASEK LONG TERM...CLB AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
148 AM EDT MON JUL 22 2013 .SYNOPSIS... FAIRLY SEASONABLE TEMPERATURES AND A NORMAL SCATTERING OF AFTERNOON STORMS ARE EXPECTED THE NEXT SEVERAL DAYS...COMPLIMENTS OF BERMUDA HIGH PRESSURE. A COLD FRONT DROPPING CLOSE TO THE REGION ON THURSDAY WILL STALL AND KEEP THE WEATHER A BIT MORE UNSETTLED. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 2:00 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: WATER VAPOR IMAGERY SHOWS AN ANTICYCLONIC (CLOCKWISE) SPIN OVER THE EASTERN CAROLINAS. MODELS ARE STRUGGLING TO CONSISTENTLY LOCATE REGIONS OF CYCLONIC CURVATURE THAT MAY BE HELPING SUSTAIN CLUSTERS OF SHOWERS AND T-STORMS. AGAIN REFERENCING WATER VAPOR IMAGERY IT APPEARS ONE UPPER DISTURBANCE LIES ACROSS CENTRAL NORTH CAROLINA INTO WEST-CENTRAL SOUTH CAROLINA...WHILE A SECOND MORE QUIESCENT DISTURBANCE LIES OFF THE GEORGIA AND SOUTHERN SOUTH CAROLINA COAST. THE AIRMASS REMAINS SEASONABLY WARM...BUT MOISTURE CONTENT AS MEASURED BY PRECIPITABLE WATER IS VERY HIGH: 2.2 INCHES. LAPSE RATES ARE NOT PARTICULARLY STEEP BUT ARE JUST LARGE ENOUGH THROUGH THE 900-600 MB LAYER TO PROMOTE GOOD UPDRAFT ACCELERATION. IR SATELLITE SHOWS CLOUD TOP TEMPERATURES MAINTAINING LARGE AREAS COLDER THAN -60C. BASED ON RECENT TRENDS AND THE LAST SEVERAL HRRR RUNS (WHICH HAVEN`T BEEN BAD THIS EVENING) THE CONVECTION ACROSS THE SC PEE DEE REGION SHOULD LARGELY DISSIPATE WITHIN THE NEXT 2-3 HOURS WHILE NEW CONVECTION DEVELOPS CLOSER TO THE COAST...ESPECIALLY THE NC COAST. AFTER 2 AM MOST OF THE CONVECTION SHOULD EXIT THE LANDMASS AND MOVE EASTWARD INTO THE OCEAN. HIGH-REFLECTIVITY (>50DBZ) CORES HAVE SO FAR REMAINED VERY LOW IN THE STORMS...BARELY ABOVE THE FREEZING LEVEL. THIS IS CORRELATED WITH EFFICIENT HEAVY RAIN PRODUCTION BUT NOT WITH SEVERE WEATHER. SINCE CELL MOVEMENT REMAINS SLOW FROM THE WEST FLOODING WILL BE THE PRIMARY THREAT TO WATCH FOR THE NEXT SEVERAL HOURS. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...COPIOUS MOISTURE REMAINS IN PLACE ON MONDAY WITH PRECIPITABLE WATER STILL ABOVE 2 INCHES. WHILE WIDESPREAD CLOUD COVER INHIBITED INSOLATION AND THUS CONVECTIVE COVERAGE TODAY THIS APPEARS A LITTLE LESS LIKELY MONDAY.FCST SOUNDINGS LESS INDICATIVE OF WIDESPREAD SC EARLY IN THE DAY SO EXPECT BETTER HEATING AND THUS COVERAGE OF STORMS. ITS HARD TO PIN DOWN ANY FAVORED AREAS FOR HIGHER POPS...ABUT A LATE DAY UPPER VORT AND SFC TROUGH MAY FOCUS ACTIVITY OVER WESTERN ZONES EVEN AS A LARGER SCALE DIURNAL WANING IS UNDERWAY. A STRONGER VORT WILL SCOOT BY TO OUR NORTH ON TUESDAY...PERHAPS AROUND MIDDAY. IN ITS WAKE WILL BE A SUPPRESSING EFFECT ON CONVECTION AND SOME 20-30 POPS SEEM ALL THAT IS WARRANTED. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...PATTERN ALOFT REMAINS AMPLIFIED THROUGH THE PERIOD WITH 5H TROUGHING OVER THE EAST COAST AND RIDGING OUT WEST. THIS MAINTAINS ACTIVE WEATHER ACROSS THE SOUTHEAST WITH PIEDMONT TROUGH AND SEA BREEZE BEING THE FOCUS ON WED. FROM THU ON WEAK COLD FRONT MOVES INTO THE REGION BUT STALLS WITH FLOW ALOFT BECOMING PARALLEL TO THE SURFACE BOUNDARY. HAVE A HARD TIME BELIEVING THE FRONT WILL MAKE IT TO THE COAST FOR ANY LENGTH OF TIME WITH THE 5H TROUGH AXIS REMAINING WEST OF THE AREA. WEAK WAVES DEVELOPING ON THE FRONT WILL BRIEFLY PUSH THE BOUNDARY TO THE COAST BEFORE ALLOWING IT TO RETURN INLAND. IN ADDITION TO NUDGING THE FRONT EAST OR WEST THESE WAVES SHOULD HELP GENERATE AND ENHANCE CONVECTION. TIMING THE FEATURES AT THIS POINT IS DIFFICULT AT BEST SO WILL MAINTAIN CHANCE POP THROUGH THE FORECAST PERIOD. FRONT WILL SLOWLY DISSIPATE DURING THE SECOND HALF OF THE PERIOD...EVENTUALLY MERGING WITH THE PIEDMONT TROUGH. NEXT WEEKEND A SHORTWAVE MOVING INTO THE MS VALLY INDUCES A SURFACE LOW WHICH THEN LIFTS NORTHEAST THROUGH THE OH VALLEY. COLD FRONT ASSOCIATED WITH THE LOW MOVES INTO THE CAROLINAS LATE IN THE PERIOD. STRONGER 5H TROUGH SUGGESTS THIS FRONT MAY HAVE A BETTER CHANCE OF REACHING OR MOVING OFF THE COAST. AT THE VERY LEAST IT WILL RESULT IN AN INCREASE IN PRECIP CHANCES FOR THE WEEKEND...ESPECIALLY SUN. DAILY CONVECTION AND CLOUD COVER WILL KEEP HIGHS NEAR TO SLIGHTLY BELOW CLIMO WHILE SOUTHERLY FLOW...MOISTURE AND LEFT OVER DEBRIS CLOUD KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...AN AREA OF LIGHT TO MODERATE SHOWERS FROM KFLO TO KLBT WILL GRADUALLY DISSIPATE OVER THE NEXT SEVERAL HOURS. AFTER THE PRECIPITATION ENDS MVFR CONDITIONS WILL GIVE WAY TO IFR CIGS/VSBYS AS FOG DEVELOPS. AT THE COASTAL TERMINALS...SHOWERS WILL OCCUR MAINLY OFFSHORE THUS WILL INDICATE VCSH THROUGH SUNRISE. SCATTERED CLOUDS AT THE IFR LEVEL WITH TEMPO BROKEN MVFR CEILINGS CAN BE EXPECTED. TEMPO IFR CIGS SHOULD OCCUR MAINLY IN THE PRE-DAWN HOURS. ANY IFR CIGS SHOULD RISE TO MVFR BY 14Z WITH VFR DEVELOPING LATE MORNING INTO EARLY AFTERNOON. SHOULD BE A GOOD CHANCE OF VCSH AT THE COASTAL TERMINALS BY NOON LOCAL WITH VCTS DEVELOPING AT KFLO/KLBT WITH THE APPROACH OF AN UPPER IMPULSE. THIS ACTIVITY WILL LIKELY PERSIST INTO THE EVENING HOURS. EXTENDED OUTLOOK...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THURSDAY...WITH BRIEF LOCALIZED PERIODS OF MVFR/IFR POSSIBLE. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM/THROUGH TONIGHT/... AS OF 2:00 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: WINDS FINALLY SURGED UP IN THE LAST FEW HOURS BUT ARE STILL WELL BELOW ADVISORY THRESHOLDS. RECENT GUSTS INCLUDE 21 KNOTS AT THE FRYING PAN SHOALS BUOY...NORTH MYRTLE BEACH...AND OAK ISLAND...20 KNOTS ON BALD HEAD ISLAND...AND 19 KNOTS IN GEORGETOWN. THESE STRONGER SOUTHWEST WINDS MAY CONTINUE THROUGH 11 PM OR MIDNIGHT BEFORE A LANDBREEZE PRODUCES MUCH LIGHTER WEST-SOUTHWEST WINDS NEAR THE BEACHES...SPREADING OUT AWAY FROM THE COAST OVERNIGHT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...WEAK WAVE OF LOW PRESSURE NEAR DELMARVA WILL VEER LOCAL FLOW SLIGHTLY TO A MORE WESTERLY DIRECTION THAN THE TYPICAL SW FOR PART OF MONDAY. LATER IN THE DAY SW FLOW GETS ESTABLISHED WITH ABOUT A 5KT INC IN SPEED. THIS TREND WILL CONTINUE INTO MONDAY NIGHT BUT NOT TO WHERE CAUTIONARY HEADLINES WARRANTED AS SEAS NOT EXPECTED TO BUILD QUITE ENOUGH WITHIN 20NM BORDER. PIEDMONT TROUGHINESS DEVELOPS LATER FRIDAY AND SHOULD MAINTAIN SLIGHTLY HIGHER WIND SPEEDS THAN WHAT SEASONABLE...15 TO 20KT MOST ZONES. A LITTLE LIGHTER FLOW OVER SRN LEGS WHICH SHOULD PREVENT 5 FT SEAS OFF GTOWN. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD WITH WATERS IN BETWEEN BERMUDA HIGH AND PIEDMONT TROUGH/WEAK COLD FRONT. WINDS AND SEAS WILL BE HIGHEST EARLY IN THE PERIOD. GRADIENT RELAXES AS FRONT/TROUGH MOVE CLOSER TO THE COAST AND WEAK SURFACE WAVES DEVELOP ON THE BOUNDARY. SPEEDS WILL BE 10 TO 15 KT WED THEN DECREASE TO AROUND 10 KT FOR THU AND FRI. SEAS WILL FALL FROM 3 TO 4 FT ON WED TO AROUND 2 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ AVIATION...MRR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1152 PM CDT SUN JUL 21 2013 .UPDATE... ISSUED AT 1147 PM CDT SUN JUL 21 2013 LONE SEVERE STORM CONTINUES TO PROPAGATE SE INTO CENTRAL PORTION OF THE FORECAST AREA WITH VERY LITTLE HAPPENING ELSEWHERE. CONTINUED TO ADJUST POPS BASED ON CURRENT AND EXPECTED PCPN TRACK. NO OTHER CHANGES MADE. UPDATE ISSUED AT 945 PM CDT SUN JUL 21 2013 DEEP CONVECTION WEAKENED EARLY THIS EVENING AS IT MOVED INTO THE FAR WESTERN FORECAST AREA. T IS NOW VERY ISOLATED WITH STRONGEST CELL JUST NORTH OF LAKOTA. LOW LEVEL JET FORECAST TO INCREASE WITH BEST CONVERGENCE ALONG INTERNATIONAL BORDER AREA OF MN OVERNIGHT. HAVE MAINTAIN HIGHEST POPS THIS AREA THROUGH MOST OF THE NIGHT. ELSEWHERE STORM POTENTIAL MORE IN QUESTION AND HAVE OVERALL DECREASED POPS SIGNIFICANTLY ACROSS SOUTH HALF OF FA WITH LACK OF CONVERGENCE AND FAVORED MID LEVEL SUPPORT IN CANADA. ANY OTHER CHANGES TO FORECAST MINOR. UPDATE ISSUED AT 633 PM CDT SUN JUL 21 2013 LINE OF DEEP CONVECTION EXTENDING FROM NEAR PILOT MOUND MB TO RUGBY AND WEST OF BIS. BASED ON CURRENT TIMING ADJUSTED POPS DELAYING HIGHER POPS ACROSS NW AND KEEPING SOUTHERN FA DRY LONGER. NO OTHER CHANGES THIS UPDATE. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 303 PM CDT SUN JUL 21 2013 MAIN CHALLENGE CONTINUES TO BE TSTM CHANCES AND SEVERITY FOR TONIGHT. LATEST MODEL GUIDANCE CONTINUES TO SUPPORT A THREAT FOR PORTIONS OF THE FA BUT EARLY ON MAINLY FOR THE KDVL REGION AS IT SHOULD TAKE A WHILE TO REACH THE RED RIVER VALLEY. CURRENTLY HAVE A COLD FRONT WORKING INTO FAR NORTHWEST ND WITH AN AREA OF LOW PRESSURE THERE AS WELL. A WARM FRONT EXTENDS SE FROM THIS LOW DOWN TO NEAR KBIS AND KABR. IN THIS WARM SECTOR DEW POINTS ARE GENERALLY IN THE LOW TO MID 60S WITH TEMPS IN THE 80S. EAST OF THE WARM FRONT DEW POINTS HAVE BEEN SLOW TO RECOVER FROM MORNING LOWS WITH 50S STILL COMMON. THERE HAS BEEN A WEAK TSTM COMPLEX OVER SOUTHWEST MANITOBA RIDING AHEAD OF THE MAIN SHORT WAVE. THIS SHOULD GET INTO THE FAR NW FA IN THE NEXT HOUR OR SO. INSTABILITY IS WEAK OUT AHEAD OF THIS INITIAL COMPLEX BUT IT MAY CONTINUE TO MOVE EAST ALONG THE BORDER WITH THE UPPER JET DYNAMICS IN PLACE. THE SEVERE THREAT SHOULD BE BEHIND THIS COMPLEX CLOSER TO THE COLD FRONT AND SFC LOW OVER WESTERN ND. INSTABILITY IS BETTER HERE WITH THE ABOVE MENTIONED WARMER AND MOIST AIR. THE MAIN SHORT WAVE ENERGY APPEARS TO BE LOCATED OVER SOUTHERN ALBERTA WHICH IS NEARING THE SFC BOUNDARY. WITH THE WAVE AND THE UPPER JET ENERGY A MORE ORGANIZED TSTM COMPLEX IS EXPECTED TO GET UNDERWAY OUT WEST. SPC HAS ISSUED MCD 1456 AND A NEW TORNADO WATCH FOR PORTIONS OF WESTERN AND CENTRAL ND. THERE HAVE BEEN A COUPLE OF CELLS THAT HAVE POPPED UP NEAR KISN THAT MAY BE THE START OF SOME STRONGER CELLS. NOT EXPECTING ANY STRONG STORMS TO APPROACH OUR WESTERN FA FOR A FEW MORE HOURS YET SO WE WILL HAVE TIME TO WATCH AND SEE HOW THINGS DEVELOP. LATEST RAP BRINGS SOME STORMS INTO OUR WESTERN FA IN THE 01-02Z MON TIME FRAME. NSSL WRF IS A LITTLE FASTER AND AS MENTIONED IN AN EARLIER AFD UPDATE IT DID BRING TSTMS A LOT FURTHER SOUTH THAN WHAT IS ANTICIPATED. FOLLOWED MORE CONTINUITY AND KEPT HIGHER PCPN CHANCES ACROSS THE NORTHERN HALF OF THE FA TONIGHT WITH LOWER CHANCES ACROSS THE SOUTH. THE COMBINATION OF THE LOW LEVEL JET UPPER JET AND THE WAVE SHOULD KEEP SHOWERS AND TSTMS GOING AFTER DARK JUST NOT SURE HOW LONG THE SEVERE POTENTIAL WILL GO. LEFT SOME LINGERING LOW PCPN CHANCES ACROSS THE EAST ON MONDAY MORNING WITH DRYING ACROSS THE WEST. SHOULD BE A FAIRLY NICE DAY WITH DRIER AIR MOVING BACK IN WITH NORTHWEST WINDS. MON NIGHT WILL BE A LITTLE COOL AGAIN ESPECIALLY ACROSS THE NORTH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 303 PM CDT SUN JUL 21 2013 SHOULD REMAIN DRY TUE WITH FAIRLY LIGHT WINDS DUE TO THE PROXIMITY OF THE SFC HIGH. CHANCES FOR PCPN RETURN BY TUE NIGHT AND WED ALTHOUGH MODELS NOT IN VERY GOOD AGREEMENT ON THE DETAILS. WEDNESDAY NIGHT-SUNDAY...12Z MODELS MAINTAIN SIMILAR IDEA AS PREVIOUS RUNS. NORTHWEST FLOW ALOFT INTO FRIDAY WITH UPPER RIDGING BUILDING INTO THE REGION FOR THE WEEKEND. THERE WILL BE SLIGHT THUNDERSTORM CHANCES WITH ANY UPPER WAVE WITHIN THE NORTHWEST FLOW ALOFT...WITH THESE CHANCES ENDING ONCE THE RIDGING BUILDS INTO THE REGION. TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL VALUES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1147 PM CDT SUN JUL 21 2013 CONFINED T MENTION TO BJI AND TVF FOR THE NEXT COUPLE HOURS. LONE STRONG/SEVERE STORM WILL CONTINUE TO PROPAGATE SE INTO CENTRAL PORTION OF FORECAST AREA. MVFR CIGS/VSBY IN STRONGER STORM OTHERWISE VFR. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...GODON LONG TERM...GODON/TG AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
121 AM EDT MON JUL 22 2013 .SYNOPSIS... A WEAK STATIONARY FRONT ACROSS THE SOUTHERN OHIO VALLEY WILL REMAIN IN PLACE INTO MONDAY EVENING BEFORE DISSIPATING. AN UPPER LEVEL DISTURBANCE WILL TRACK EAST CROSSING THE REGION LATER MONDAY NIGHT AND EARLY TUESDAY. DEEP MOISTURE IN ASSOCIATION WITH THESE FEATURES WILL KEEP ROUNDS OF SHOWERS AND THUNDERSTORMS GOING EARLY THIS WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 1000 PM EDT SUNDAY... FOLLOWING CLOSE TO THE HRRR WHICH HIGHLIGHTS MORE THREAT OF SHOWERS FROM SE WV EAST NORTHEAST INTO THE SOUTHERN SHENANDOAH VALLEY OVERNIGHT BEFORE DIMINISHING. KEPT ISOLATED TO NONE IN THE SOUTH. NOT MUCH CHANGE IN THE REST OF THE FORECAST AS WE SHOULD SEE PATCHY FOG WITH MOSTLY CLOUDY SKIES. OVERNIGHT LOWS WILL REMAIN ON THE MILD SIDE...GENERALLY FALLING INTO THE MID 60S TO LOW 70S. EXPECT GREATER COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY FOR MONDAY AS A STRONGER UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST. ONCE AGAIN...THE GREATEST THREAT NORTH OF INTERSTATE 81 WILL BE LOCALLY HEAVY RAIN...WITH RAINFALL RATES OF AN INCH OR MORE OVER A FEW MINUTES TIME. AS SUCH...WILL AGAIN BE CONCERNED WITH LOCALIZED FLASH FLOODING. WILL LEAVE THE DECISION OF THE TIMING AND LOCATION OF A FLASH FLOOD WATCH TO THE OVERNIGHT SHIFT...GIVING THEM AN OPPORTUNITY TO LOOK AT ANOTHER SET OF SYNOPTIC WEATHER MODELS. SOUTH OF INTERSTATE 81...WILL ALSO SEE A SLIGHTLY GREATER THREAT OF STRONG TO SEVERE THUNDERSTORMS DURING THE AFTERNOON AND EVENING DUE TO STRONGER SURFACE HEATING. STUCK PRETTY CLOSE TO MET GUIDANCE FOR AFTERNOON TEMPERATURES...WITH HIGHS REACHING THE UPPER 70S AND LOW 80S WEST...AND REACHING TO AROUND 90 ACROSS THE PIEDMONTS. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AS OF 340 PM EDT SUNDAY... WELL DEFINED SHORT WAVE CROSSES THE FORECAST AREA MONDAY NIGHT AND TUESDAY. THIS WILL KEEP A BETTER PROBABILITY OF PRECIPITATION OVERNIGHT THAN JUST THE TYPICAL DIURNAL CYCLE OF THE PAST FEW DAYS. UPPER TROF AMPLIFIES ENOUGH THAT THE FRONT WILL PUSH SOUTH OF THE FORECAST AREA ON WEDNESDAY. AS THE FRONT COMES THROUGH ON WEDNESDAY THE EXPECTING MORE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON AND EVENING. WITH THE PASSAGE OF THE SHORT WAVE...MID LEVEL TEMPERATURES COOL SLIGHTLY WHICH WILL ENHANCE THE LAPSE RATES AND INSTABILITY. LITTLE CHANGE IN DAILY HIGH AND LOW TEMPERATURES AND IN MOISTURE OF THE AIR MASS. STAYED CLOSE TO MODEL GUIDANCE FOR MAXIMUM AND MINIMUM TEMPERATURES EACH DAY. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 1140 AM EDT SUNDAY... NO CHANGE IN THE OVERALL PATTERN THROUGH THE EXTENDED PERIOD. MODELS BRINGING STRONG ENOUGH SHORT WAVE THROUGH THE EASTERN UPPER TROF ON THURSDAY TO PUSH A SURFACE FRONT INTO THE SOUTHEAST STATES. THIS WOULD BRING WINDS AROUND TO THE NORTHWEST AND NORTH. MAY NOT COMPLETELY ELIMINATE THE PROBABILITY OF PRECIPITATION FOR THE FORECAST AREA...BUT CHANCES ON THURSDAY AND FRIDAY SHOULD BE LESS THAN IN RECENT DAYS. SOME SIGNS IN THE MODELS OF ACTUAL DRIER AIR REACHING THE FORECAST AREA. SUBTLE DROP IN 850 MB TEMPERATURES BEHIND THE FRONT...OTHERWISE NEAR NORMAL FOR HIGHS AND LOWS THROUGH DAY 7/SUNDAY. SURFACE LOW PRESSURE OVER THE MISSISSIPPI VALLEY ON SATURDAY WILL APPROACH THE REGION BY SUNDAY. WINDS WILL BE BACK AROUND TO THE SOUTHWEST WITH DEEP MOISTURE RETURNING AHEAD OF THE LOW. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 1250 AM EDT MONDAY... EARLIER SHOWERS HAVE ALL BUT FADED EXCEPT ACROSS THE GREENBRIER VALLEY WHERE A CLUSTER REMAINS MAINLY JUST WEST OF KLWB. EXPECT THIS PRECIP TO SLOWLY EXIT TO THE NORTH IN THE NEXT HOUR LEAVING AREAS OF LOW CLOUDS AND FOG WHICH SHOULD DROP KLWB TO IFR/LIFR IN THE NEXT COUPLE OF HOURS. ELSW LINGERING DEBRIS MID DECK MAY TEND TO LIMIT FOG FORMATION INITIALLY BUT EXPECT ENOUGH THINNING OVERNIGHT TO ALLOW AREAS OF DENSE FOG ESPCLY EAST WHERE EARLIER MORE WIDESPREAD HEAVY RAINFALL OCCURRED. THUS STILL THINKING MVFR WITH MORE IFR EAST AND AROUND KBCB...WITH POTENTIAL LOW CIGS AT KBLF. COVERAGE OF SHOWERS AND STORMS LOOKS BETTER MONDAY AND EVEN THOUGH THIS IS LIKELY...KEPT VCTS IN THE TAFS AND PREDOMINAT SHOWERS...AS MODELS STILL SHOWING AT LEAST SOME PERIODS OF LESS COVERAGE MAINLY EAST OF THE BLUE RIDGE EARLY ON. MAIN CONCERNS WITH THIS DISTURBANCE WILL AGAIN BE HEAVY RAIN...RESULTING IN PERIODIC IFR CONDITIONS AT ALL AIRPORTS. A FEW SEVERE STORMS WILL ALSO BE POSSIBLE...MORE SO FOR KDAN AND KLYH WHERE STRONGER DAYTIME HEATING WILL ADD TO ATMOSPHERIC INSTABILITY DURING THE AFTERNOON. SHOWERS MAY LINGER INTO MONDAY EVENING WITH THE ACTUAL TROF AXIS CROSSING THE REGION DESPITE LOSS OF HEATING SO EXTENDING SHRA MENTION AT MOST LOCATIONS PAST SUNSET. MODELS CONTINUE TO DEPICT THE STALLED FRONT HOLDING JUST NORTH OF THE AREA THROUGH EARLY TUESDAY...BEFORE LIFTING AS A LOW PRESSURE SYSTEM MOVES ACROSS THE WESTERN GREAT LAKES. REGARDLESS...EXPECT DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS TO PERSIST THROUGH THE COMING WORKWEEK AS GULF MOISTURE REMAINS ABUNDANT ACROSS THE AREA. ANOTHER COLD FRONT WILL APPROACH THE OHIO RIVER TOWARD THE END OF THE WORKWEEK...BUT DO NOT SEE THE FRONT ADVANCING MUCH FURTHER SOUTH THAN THAT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/NF NEAR TERM...NF/WP SHORT TERM...AMS/RCS LONG TERM...AMS AVIATION...JH/NF/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
335 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING. LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON. THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500 TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS. CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800 MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON. ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE DAMAGING WINDS. THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE 19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS. OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 AM CDT MON JUL 22 2013 SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES. NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND 80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY. PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90 DURING THE DAY ON SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1100 PM CDT SUN JUL 21 2013 FOG/STRATUS DEVELOPMENT A CONCERN OVERNIGHT. BUFKIT SOUNDINGS INDICATE A MOIST NEAR SFC LAYER //AIDED BY RAINFALL TODAY// UNDER AN INVERSION NEAR 900 MB. T/TD SPREAD OF 3-7 DEGREES ALREADY AT 03Z WITH CLEAR SKIES OVERHEAD. HOWEVER...THE SOUNDINGS KEEP WINDS STIRRED JUST OFF THE SFC..10+ KTS BY 200 FT. THIS WOULD GENERALLY FAVOR MORE OF A STRATUS THREAT THAN DENSE FOG. WILL STAY WITH THIS TREND IN THE TAFS. COLD FRONT SLATED TO SINK ACROSS THE AREA LATER FRIDAY AFTERNOON/EVENING...WITH A SWITCH TO NORTHWEST WINDS NEAR/SHORTLY AFTER 00Z. LOW LEVEL INVERSION WILL SERVE TO KEEP THE ATMOSPHERE CAPPED FOR MUCH OF THE DAY...BUT THE FRONT SHOULD PROVIDE ENOUGH FORCING TO FIRE A LINE OF SHRA/TS BETWEEN 19-21Z...WHICH WILL TRACK ACROSS THE TAF SITES. COULD BE SOME STRONG/SEVERE STORMS. CONFIDENCE INCREASING IN THIS SCENARIO AND WILL REFLECT THIS IN THE TAFS. EXPECTING SOME ENHANCED GUSTINESS AROUND THE STRONGER STORMS. PCPN WILL CLEAR WITH THE BOUNDARY...BUT CLOUDS COULD LINGER THROUGH THE EVENING HOURS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1159 PM CDT SUN JUL 21 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 330 PM CDT SUN JUL 21 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COUPLE SHORTWAVES UPSTREAM...ONE OVER WESTERN WISCONSIN WHICH IS RESPONSIBLE FOR THE CLUSTER OF SHOWERS AND STORMS MOVING OVER CENTRAL WISCONSIN...AND ANOTHER OVER IOWA. MAINLY THE SOUTHERN PORTION OF THE FORECAST AREA WILL BE IMPACTED WITH THESE STORMS FOR THE REST OF THE AFTERNOON...BUT NO SEVERE WEATHER IS EXPECTED. FURTHER UPSTREAM...THE NEXT SHORTWAVE IS PRODUCING STORMS OVER FAR SOUTH-CENTRAL CANADA AND NORTHERN NORTH DAKOTA WHICH WILL ARRIVE TOMORROW. PRECIP CHANCES FOR THE REST OF TODAY AND SEVERE WEATHER CHANCES TOMORROW ARE THE MAIN FORECAST CONCERNS. TONIGHT...SHORTWAVE IMPULSES MOVING EAST ACROSS THE REGION WILL TAKE UNTIL MID TO LATE EVENING TO EXIT. AS A RESULT...POTENTIAL WILL BE THERE FOR ISOLATED TO SCATTERED THUNDERSTORMS UNTIL THEN OVER THE SOUTHERN FORECAST AREA...EVEN THOUGH THE MAIN CLUSTER WILL HAVE PROBABLY EXITED BY THE START OF THE EVENING. PLENTY OF CLEARING OCCURRING UPSTREAM OF THE SHORTWAVES...THOUGH MODELS DEPICT WEAK ISENTROPIC ASCENT CONTINUING THROUGH THE NIGHT. AM THINKING WILL SEE A PERIOD OF SUBSIDENCE BEHIND THE WAVE...WHICH COULD LEAD TO A SEVERAL HOURS OF MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS. NOT SURE HOW LONG THIS WILL LAST...BUT 850MB THETAE ADVECTION DOES RAMP UP LATE AHEAD OF THE SHORTWAVE CURRENTLY MOVING INTO NORTHERN NORTH DAKOTA. NOT OUT OF THE QUESTION THAT CONVECTION COULD APPROACH N-C WISCONSIN LATE TONIGHT. SO WILL SHOW INCREASING CLOUDS AFTER MIDNIGHT ALONG WITH SLIGHT CHANCE TO CHANCE POPS OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. LOWS MAINLY IN THE MID 50S TO LOW 60S. MONDAY...THE NORTH DAKOTA SHORTWAVE WILL MOVE ACROSS NORTHERN WISCONSIN DURING THE MORNING. BOTH THE NAM AND GFS SHOW A DECENT WIND SHIFT OCCURRING AT 700MB SO WOULD NOT BE SURPRISED TO SEE SOME CONVECTION MOVE ACROSS THE NORTH. THEN A STRONG SHORTWAVE OVER WESTERN ONTARIO WILL DRIVE A COLD FRONT ACROSS NORTHWEST WISCONSIN DURING THE AFTERNOON. DEPENDING UPON IF PRECIP OCCURS OVER NORTHERN WISCONSIN AND HOW MUCH DESTABILIZATION CAN OCCUR WITH AMPLE CLOUD COVER...MODIFYING PROGGED SOUNDINGS NEAR RHINELANDER FOR AN 80F/64F PARCEL YIELDS 1700 J/KG OF ML CAPE AT 21Z. WITH 0-6KM BULK SHEAR VALUES OF 30-35KTS...POTENTIAL WILL BE THERE FOR SEVERE STORMS TOMORROW AFTERNOON OVER N-C AND POSSIBLY CENTRAL WISCONSIN TOO. WARM ADVECTION AHEAD OF THE FRONT WILL PUSH HIGHS TO THE UPPER 70S AND MID 80S. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 330 PM CDT SUN JUL 21 2013 NOT MUCH CHANGE IN THE OVERALL FORECAST FOR THIS PERIOD AS SHORTWAVE TROFS MOVE THROUGH MEAN TROF POSITION ACROSS GREAT LAKES. LATEST GFS AND ECMWF IN GENERAL AGREEMENT THROUGH MOST OF PERIOD ON STRENGTH AND TIMING OF SYSTEMS. TEMPS WILL BE AOB NORMAL FOR MUCH OF WEEK...AFTER MONDAY. IN FACT...HIGHS NEXT WEEKEND MAY STRUGGLE TO REACH 70 ACROSS PARTS OF THE NORTH AS NW FLOW IS REINFORCED BEHIND LATE WEEK SYSTEM. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1159 PM CDT SUN JUL 21 2013 PATCHY IFR/MVFR CIGS WILL LINGER OVER THE REGION OVERNIGHT DUE TO RETURN FLOW AHEAD OF A APPROACHING COLD FRONT. AREAS OF FOG WILL ALSO DEVELOP WHERE CLEAR SKIES PREVAIL. MORE MVFR CIGS AND VSBYS DUE TO SHOWERS AND STORMS LIKELY ALONG THIS FRONT STARTING MONDAY AFTERNOON OVER NORTHWEST WISCONSIN BEFORE REACHING SOUTHEAST WISCONSIN MONDAY NIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......JKL AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
724 AM EDT MON JUL 22 2013 .SYNOPSIS... A STALLED FRONT SOUTH OF NEW ENGLAND WILL PUSH NORTH ACROSS THE REGION LATE TONIGHT INTO TUESDAY BRINGING NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL POSSIBLE. A COLD FRONT WILL SWEEP ACROSS NEW ENG WEDNESDAY FOLLOWED BY COOLER AND LESS HUMID WEATHER THURSDAY AND FRIDAY. WARMER AIR RETURNS FOR NEXT WEEKEND BEFORE A COLD FRONT NEXT SUN MAY BRING ADDITIONAL SCATTERED SHOWERS/THUNDERSTORMS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 7 AM UPDATE... SURFACE FRONTAL BOUNDARY REMAIN SOUTH OF THE REGION WHILE VERTICAL WIND PROFILERS ARE EXHIBITING LIGHT SOUTHERLY FLOW ACROSS LONG ISLAND WITH A MORE EASTERLY COMPONENT OVER THE TAUNTON WEATHER FORECAST OFFICE. WHETHER THE QUASI-STATIONARY STORM OVER THE SOUTHERN WATERS IS A SIGN OF THINGS TO COME...THERE IS SURELY CONCERN OVER THE POTENTIAL FOR PERSISTENT HEAVY RAIN ALONG THE SURFACE FRONTAL BOUNDARY AS IT SLOWLY LIFTS NORTH TODAY. WAVERING CONFIDENCE WITH HOW THE TODAYS WEATHER IS GOING TO SPECIFICALLY PLAY OUT. FEEL A BLEND OF THE SREF/NAM/ECMWF IS A GOOD STARTING POINT. WRF-MODEL SOLUTIONS AND THE HRRR ARE VALUABLE APPROXIMATIONS OF POTENTIAL SCENARIOS WHEN EVALUATING SIMULATED RADAR REFLECTIVITY. TWO AREAS OF CONCERN: TRAINING OF PERSISTENT RAIN AND EMBEDDED HEAVIER SHOWERS / THUNDERSTORMS ALONG THE FRONTAL BOUNDARY...AND THE POTENTIAL FOR BOUNDARY LAYER DESTABILIZATION ACROSS THE INTERIOR. SO THERE COULD BE ISSUES ALONG THE SOUTH COAST ALONG WITH INTERIOR SHOWERS. ECHO THE PREVIOUS FORECASTERS THINKING...THERE IS ENOUGH MOISTURE IN THE COLUMN FOR MORE CLOUDS THAN SUNSHINE AND MODELS ARE GENERATING MARGINAL INSTABILITY TO SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS AS WEAK SHORTWAVE ENERGY APPROACHES FROM THE GREAT LAKES. THUS THE BEST CHANCE FOR CONVECTION WILL BE ACROSS CENTRAL AND WESTERN AREAS FURTHER REMOVED FROM MORE STABLE MARITIME AIR. CAPES ARE FORECAST TO BE AOB 1000 J/KG WITH POOR MID LEVEL LAPSE RATES SO SEVERE WEATHER IS NOT ANTICIPATED...BUT A HEAVY RAIN THREAT WITH THE POTENTIAL FOR LOCALIZED FLOODING WILL EXIST. EASTERLY FLOW DEVELOPS WHICH WILL RESULT IN COOLER TEMPS WITH MAXES MOSTLY UPPER 70S TO LOWER 80S...BUT IT WILL BE HUMID WITH DEWPOINTS FORECAST TO INCREASE TO NEAR 70. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... MID LEVEL TROF ACROSS THE GT LAKES FORECAST TO MOVE EAST TOWARD NEW ENGLAND LATE TONIGHT INTO TUE WITH MULTIPLE SHORTWAVES MOVING THROUGH THE FLOW. THE SFC BOUNDARY TO THE S WILL BEGIN TO MOVE BACK AS A WARM FRONT LATER TONIGHT BUT IT IS UNCERTAIN HOW FAR N THIS BOUNDARY WILL GET ON TUE. WE DISCOUNTED THE GFS WHICH APPEARS TOO AGGRESSIVE WITH PUSHING THE FRONT INTO N NEW ENG. WE USED A BLEND OF NAM/ECMWF WHICH BRINGS IT INTO SNE ALTHOUGH THE EXACT LOCATION IS UNCERTAIN. WE EXPECT INCREASING COVERAGE OF SHOWERS/TSTMS LATE TONIGHT INTO TUE AS THE SHORTWAVES MOVE INTO NEW ENG WITH RIGHT ENTRANCE REGION OF UPPER JET PROVIDING EXTRA DYNAMICAL SUPPORT. PWATS INCREASE TO GREATER THAN 2" SO PRIMARY THREAT WILL BE LOCALLY HEAVY RAINFALL. LOCATION OF THE SFC BOUNDARY WILL DETERMINE WHERE AXIS OF HEAVIEST RAINFALL SETS UP WHICH AT THIS TIME APPEARS TO BE NORTH AND WEST OF THE I95 CORRIDOR...BUT THIS COULD CHANGE. SEVERE THREAT IS LOW DUE TO ABUNDANT CLOUD COVER AND WEAK SHEAR. MAXES TUE WILL BE IN THE UPPER 70S TO LOWER 80S AND CONTINUED QUITE HUMID AS DEWPOINTS INCREASE INTO THE LOWER 70S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HEADLINES... * WET WEATHER DIMINISHING INTO WEDNESDAY * DRY AND SEASONABLE CONDITIONS PREVAIL FOR THE LATE WEEK * SEVERE WEATHER POSSIBLE FOR SATURDAY AND AGAIN SUNDAY? * DRY AND BELOW-SEASONABLE CONDITIONS HINTED FOR NEXT WEEK */OVERVIEW AND MODEL CONSENSUS... SUITE OF FORECAST GUIDANCE FINALLY COMING INTO BETTER AGREEMENT WHILE NO LONGER SUGGESTING ANOMALOUS DEEP NORTHERN STREAM TROUGHING ACROSS THE EASTERN CONUS. FEEL AN EQUAL BLEND OF DETERMINISTIC FORECAST GUIDANCE IS WELCOMED...BUT AM CAUTIOUS AS THIS IS ONLY THE FIRST INSTANCE OVER THE PAST WEEK IN WHERE THE GUIDANCE HAS BECOME WELL-ALIGNED. JUST YESTERDAY OUTCOMES WERE CONSIDERABLY DIFFERENT ACROSS THE NORTHEASTERN CONUS. AM WANTING TO SEE MODEL CONSISTENCY FOR THE NEXT COUPLE OF RUNS PRIOR TO JUMPING ON ANY ONE THOUGHT PROCESS...SO AGREE WITH WPC/HPC IN UTILIZING ENSEMBLE MEANS AS ELSEWHERE ACROSS THE CONUS...ESPECIALLY WITHIN THE SHORT-TERM... PACIFIC DISTURBANCES MOVING THROUGH THE BROADER LONGWAVE FLOW ARE STILL BEING HANDLED DIFFERENTLY BETWEEN FORECAST SOLUTIONS LENDING TO CONFLICTING SURFACE OUTCOMES. NOTHING IS CONCRETE. UPDATE: 22.0Z ECMWF HAS TRENDED A MORE ANOMALOUS NORTHERN STREAM TROUGHING SOLUTION. FEEL THIS IS A CONSEQUENCE OF POOR HANDLING OF PACIFIC DISTURBANCES AROUND THE DEEPER LOW OVER ONTARIO. WILL FOREGO THE SOLUTION WITH THIS FORECAST AND MAINTAIN WITH THE 22.0Z GFS AND 21.12Z ECMWF CONSISTENCY. */DAY-TO-DAY DETAILS... */TUESDAY NIGHT INTO WEDNESDAY... WEAK SURFACE LOW COUPLED TO THE RIGHT-REAR QUADRANT OF THE UPPER- LEVEL JET AND DEEP-LAYER ASCENT LIFT NORTHEASTWARD /22.0Z NAM IS SLOWEST WITH THIS OUTCOME/. WHILE A SURFACE TROUGH ATTENDANT TO THE LOW LINGERS ACROSS SOUTHERN NEW ENGLAND...THIS WILL BE WASHED OUT AS THE MAIN IMPULSE THROUGH THE BROAD TROUGH PATTERN PUSHES COOLER AND DRIER AIR BEHIND A WELL-DEFINED SURFACE COLD FRONT THROUGH THE NORTHEASTERN CONUS. THIS WILL PUSH THE DEEPER PWAT AXIS OFFSHORE LIMITING THE HEAVY RAIN THREAT. WILL DIMINISH CHANCE POPS NORTHWEST TO SOUTHEAST GRADUALLY THROUGH THE PERIOD. NO MENTION OF HEAVY RAIN WILL BE MADE TO THE FORECAST. LITTLE CONFIDENCE FOR THUNDERSTORMS WITH DRIER AIR BUILDING INTO THE REGION AND LIKELY BROADER SUBSIDENCE BEHIND THE AFOREMENTIONED MAIN IMPULSE THROUGH THE DAY WEDNESDAY. SOUTHWEST WINDS BACKING OUT OF THE NORTH-NORTHWEST AND DIMINISHING WITH FRONTAL PASSAGE. */WEDNESDAY NIGHT THROUGH FRIDAY NIGHT... AN AMAZING ABOUT FACE IN THE FORECAST GUIDANCE WHICH JUST LAST NIGHT WAS SUGGESTING CONTINUED RAIN CHANCES. WITH THIS FORECAST A SIMPLE RULE APPLIES: BETWEEN TWO REGIONS OF RISING AIR THERE NEEDS TO BE A BALANCE BETWEEN OF SINKING MOTIONS. WITH ENERGY ELONGATED ALONG AN OFFSHORE STALLED FRONTAL BOUNDARY AGAINST THE BROADER ATLANTIC RIDGE AND A STRONG IMPULSE ACROSS QUEBEC...THE NORTHEASTERN CONUS FINDS ITSELF IN A FAVORABLE REGION OF SINKING DRIER AIR. WITH BOTH THE 22.0Z GFS AND 21.12Z ECMWF NO LONGER EXHIBITING ANOMALOUS DEEP NORTHERN STREAM TROUGHING...RATHER WELL UNIFIED IN THE EVOLUTION OF AN OCCLUDED LOW PRESSURE CENTER OVER THE SOUTHERN HUDSON BAY REGION...WILL BLEND THE SOLUTIONS AND KEEP THE FORECAST PERIOD DRY. THE PREVAILING PERIOD OF BROAD HIGH PRESSURE WILL ALLOW FOR LIGHT WINDS ACROSS THE REGION. WILL LIKELY SEE SUCCESSIVE DAYS OF SEA-BREEZES ALONG THE SHORES THURSDAY AND FRIDAY. BROADER TROUGHING ACROSS THE REGION WILL KEEP TEMPERATURES SEASONABLE. SOME UNCERTAINTY ON FRIDAY...FALLING HEIGHTS WITH A WEAK TROUGH ACROSS THE REGION SUGGESTED. IF MID- TO UPPER-LIFT IS MATERIALIZES AND COLLOCATES WITH LOW-LEVEL CONVERGENCE ALONG SEA-BREEZES...IT IS PLAUSIBLE TO SEE SOME SHOWERS. BOTH THE GFS AND ECMWF SUGGEST POOR MID-LEVEL LAPSE RATES IN THE REGION OF THE LEFT-REAR QUAD OF THE UPPER-LEVEL JET...SO THIS LESSENS CONFIDENCE OF SHOWER AND T-STORM ACTIVITY. */SATURDAY INTO SUNDAY... MAIN IMPULSE AND DEEP-LOW PUSH OUT OF THE SOUTHERN HUDSON BAY REGION. ATTENDANT COLD FRONT SWEEPS THROUGH THE NORTHEASTERN CONUS DURING THE TIMEFRAME...THOUGH THE TIMING IS SOMEWHAT UNCERTAIN. NEVERTHELESS...CLIMATOLOGICALLY THE SYNOPTIC SETUP SUPPORTS THE POTENTIAL FOR SEVERE WEATHER ACROSS THE NORTHEASTERN CONUS. IT IS ENTIRELY PLAUSIBLE TO SEE SUCCESSIVE DAILY EPISODES...THE FIRST ACROSS THE NY/PA INTO WESTERN NEW ENGLAND...THE SECOND OVER NEW ENGLAND ITSELF. A DAY 6/7 FORECAST...THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY. HAVE MORE CONFIDENCE WITH THE 21.12Z ECMWF OUTCOMES. WILL GO WITH CHANCE POPS FOR SHOWERS AND THUNDERSTORMS. WON/T SPECULATE AT THIS TIME ABOUT SPECIFIC SEVERE WEATHER OUTCOMES...NOR HEAVY RAIN IMPACTS...AWAITING LATER MODEL SOLUTIONS TO EVALUATE CONSISTENCY. */INTO NEXT WEEK... CONSISTENCY BETWEEN THE 21.18Z AND 22.0Z GFS COUPLED WITH THE 21.12Z ECMWF SUGGEST HIGH PRESSURE BUILDING SOUTHEASTWARD INTO SOUTHERN NEW ENGLAND AS THE DEEP LOW OVER CANADA LIFTS NORTHEAST THROUGH QUEBEC. COOL MID-LEVEL AIR WITH SURFACE NORTHWEST FLOW SUGGESTS CONDITIONS BELOW SEASONABLE LEVELS WHILE REMAINING DRY. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. INCREASING AREAL COVERAGE OF -RA WITH EMBEDDED +RA/TSRA. WILL SEE LOWERING CIGS TOWARDS EVENING...DETERIORATING INTO THE OVERNIGHT. LIGHT AND VARIABLE WIND FLOW AS A FRONTAL BOUNDARY LIFTS THROUGH THE REGION. UNCERTAIN ON EXACT SPECIFICS AND SUBSEQUENT TRENDS... BUT CONFIDENT THAT CONDITIONS WILL DETERIORATE AS SHRA/TSRA BECOME WIDESPREAD INTO TUESDAY. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. LOWER CIGS COULD DEVELOP SOONER THAN FORECAST. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOWER CIGS COULD DEVELOP SOONER THAN FORECAST. OUTLOOK...TUESDAY NIGHT INTO FRIDAY NIGHT... TUESDAY NIGHT INTO WEDNESDAY...HIGH CONFIDENCE. SHRA AND POSSIBLE TSRA LINGERING. WILL SEE ANY MVFR/IFR CONDITIONS GRADUALLY LIFTING. COLD FRONT SWEEPING THROUGH THE TERMINALS. WILL SEE SOUTHWEST WINDS /POTENTIALLY GUSTY/ BACKING OUT OF THE NORTH- NORTHWEST AND WEAKENING. ANY COASTAL FOG SHOULD BE SCOURED OUT. WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE CONFIDENCE. VFR WITH HIGH PRESSURE IN CONTROL. SEA-BREEZES ALONG THE SHORES. PERHAPS A SLIGHT CHANCE FOR SHRA/TSRA ON FRIDAY...LOW CONFIDENCE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TUESDAY. LIGHT PRES GRADIENT WILL KEEP WINDS BELOW SMALL CRAFT CRITERIA THROUGH THE PERIOD. SEAS WILL BE BELOW SCA AS WELL BUT COULD BUILD TO 5 FT OVER THE SOUTHERN WATERS BY LATE TUE. OUTLOOK...TUESDAY NIGHT INTO FRIDAY NIGHT... TUESDAY NIGHT INTO WEDNESDAY...HIGH CONFIDENCE. COLD FRONT TO SWEEP ACROSS THE WATERS WEDNESDAY ALONG AND AHEAD OF WHICH SOUTHWEST WINDS WILL GUST UP TO AROUND 20 KTS. SHRA/TSRA ALSO LINGERING WITH POSSIBLE COASTAL FOG IMPACTS. WILL SEE CONDITIONS IMPROVE LATE AS WINDS BACK OUT OF THE NORTH-NORTHWEST AND WEAKEN. DRIER AIR BUILDING INTO THE REGION SHOULD ALLOW ANY FOG CONDITIONS TO LIFT. SEAS TO BEGIN TO SUBSIDE WITH LESSER FLOW. WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE CONFIDENCE. HIGH PRESSURE BUILDING INTO THE WATERS. WINDS BECOMING LIGHT. WAVE HEIGHTS SHOULD DIMINISH EARLY IN THE PERIOD AND REMAIN BELOW 5 FEET THROUGHOUT THE FORECAST. SEA-BREEZES WILL DEVELOP DURING THE DAY ALONG THE IMMEDIATE SHORES. && .TIDES/COASTAL FLOODING... ASTRONOMICAL TIDES WILL BE ABNORMALLY HIGH DURING THE HIGH TIDE CYLCE NEAR MIDNIGHT TONIGHT. BOS TIDE IS 12.1 FT WHICH IS ABOUT AS HIGH AS IT EVER GETS. WITH LIGHT EASTERLY FLOW EXPECT ABOUT A 0.5 FT TIDAL DEPARTURE WHICH SHOULD BE ENOUGH TO PRODUCE SOME SPLASHOVER ALONG THE MOST VULNERABLE LOCATIONS ACROSS E COASTAL MA. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...KJC/SIPPRELL SHORT TERM...KJC LONG TERM...SIPPRELL AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
613 AM EDT Mon Jul 22 2013 ...UPDATED FOR AVIATION SECTION... .NEAR TERM [TODAY]... The large scale longwave pattern is highlighted by weak ridging over Wrn Conus and a upper level trough amplifying from Great Lakes into Lwr MS Valley. Several shortwaves were noted in water vapor imagery moving across base of trough including one over NW AL. At the surface, a ridge of high pressure extends from the Atlc WWD across the FL Peninsula and Cntrl Gulf of Mexico. A weak and dissipating trough was noted across the WRN forecast area. 24hr temp/dew point comparisons indicate little change in airmass last 24 hrs. Latest radar pix shows noticeably less convection developing over the Gulf waters than forecast. Still, HRRR and WRF show marine convection moving onshore aft 10z from Panhandle waters reaching FL/AL border by 14z. Still have updated 06z-12z and 12z-18z Grids to lower POPS especially over waters and coasts and will monitor in case another update is needed. During the rest of today, progressive WSW steering flow as unseasonably amplified upper trough digs SEWD into TN Valley and deepens increasing tropical moisture plume, aided by AL shortwave moving ESE provides additional lift. Surface ridge remains to our S locally yielding SW flow. PWATs across the region from JAX west to Dothan and beyond in excess of 2 inches this aftn. This will combine with seabreeze/mesoscale outflows clashes from leftover boundaries from surface trough for sct/numerous showers and thunderstorms with heavy rain and gusty winds later today. As reflected in CAM and other models, highest POPs over the NW zones closest to the upper energy. Will go with 40-80% SE-NW POP gradient. RAP13 soundings show uni-directional very moist profiles which favor good rain producers and given recent rains, aggravate chances of at least nuisance flooding again today. CAM QPF/flood tools shows Panhandle as best bet with 1-2 inches avg STP. Although Shear unimpressive, model aftn CAPE around 2400 J/KG across SE AL. Add presence of shortwave plus any boundary clashes this favors at least strong storms to isold severe storms with best bet SE AL/ adjacent GA/FL 21z-00z. This, along with max temps will be partly dependent on amount of morning cloudiness and where drier air sets making max temp forecast a little tricky. Inland Highs generally 88 to 90. && .SHORT TERM [Tonight through Wednesday]... The pattern will transition to more of a northwest flow aloft through the short term as the upper level trough axis moves east of the area. A series of shortwaves is expected to move through the base of the trough and aid in convective development over the forecast area (PoPs 40-60% during the day). The northwest flow aloft will also aid in advecting steeper than normal mid-level lapse rates into the area by Tuesday into Wednesday, which may increase the threat of isolated, pulse severe storms. These would be most likely over the northern and western portions of the area. The 22/00z GFS forecasts 700-500 mb lapse rates between 6-7 C/km, which is 1-1.5 C/km above climo for this time of year. && .LONG TERM [Wednesday Night through Sunday]... The upper flow across the CONUS will be dominated by an eastern trough and western ridge. Through most of the extended period, the upper trough axis is forecast to be just east of the CWA, with northwest flow aloft. While this flow is typically drier across the region, the presence of a nearly stationary trough across the northern half of the area will offset this to some extent. With this in mind, will generally keep the PoPs at or below 50 percent through the extended, especially for Thursday into the weekend. With the slightly lower rain chances than the past several days, expect high temperatures to creep back into the lower to mid 90s as well. && .MARINE... With a persistent trough to the north and high pressure to the south, winds over the marine area will be primarily out of the southwest to west-southwest this week between 10 and 15 knots. && .AVIATION...[Through 12Z Tuesday] Although locales except DHN and TLH remain VFR at 10z, HRRR show showers and thunderstorms developing at our western terminals spreading E/NE reaching the FL/AL border thru 14z. Therefore decided to include MVFR CIGS 12-14z at above sites. After morning showers and thunderstorms diminish, there will likely be a break, and then another round in the afternoon with conditions very similar to what we saw on Sun with MVFR CIGS/VSBYS and gusty winds in any heavy rain or strong storms. After 00z VFR conditions return but after 07z, MVFR CIGS and possibly VSBYS especially where any residual moister remains form earlier storms. Brief IFR CIGS and MVFR VSBYS also possible near sunrise. && .FIRE WEATHER... Red flag conditions are not expected for the next several days. && .HYDROLOGY... A few rivers still remain at or near flood stage, including the Aucilla and Econfina rivers. The Steinhatchee river is also out of its banks south of US 19 with minor flooding expected downstream of the gage for the next day or two. Scattered showers and storms are expected through much of this week, but should not be sufficient to produce widespread flooding. However, localized areas of heavy rain are likely and could cause some urban and small stream flooding on occasion. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 89 74 92 74 93 / 60 50 60 50 50 Panama City 86 76 88 76 88 / 60 50 60 40 50 Dothan 88 73 92 73 91 / 70 40 60 50 50 Albany 89 73 92 74 92 / 70 40 60 40 50 Valdosta 89 73 92 74 94 / 70 40 60 40 50 Cross City 89 73 88 73 90 / 50 40 60 40 50 Apalachicola 86 77 88 77 90 / 60 50 60 40 50 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Risk for Rip Currents for FLZ108-112-114. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Wx...Block Short Term/Marine/Hydrology...DVD Long Term...Camp
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
713 AM EDT MON JUL 22 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE AT THE SURFACE AND ALOFT WILL PREVAIL ALONG THE EAST COAST THROUGH MID WEEK. A WEAKENING COLD FRONT WILL APPROACH FROM THE NORTHWEST LATE WEDNESDAY THROUGH THURSDAY... STALLING NEAR THE AREA INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MADE A FEW CHANGES WITH THE EARLY MORNING UPDATE. 1. LOWERED POPS IN THE CHARLESTON TRI COUNTY AREA TO 40 PERCENT AND INCREASED POPS TO 70 PERCENT OVER PORTIONS OF LONG...MCINTOSH AND LIBERTY COUNTIES PER LATEST RUNS OF HIGH RESOLUTION MODELS. BOTH THE RAP AND H3R NOW FOCUS MOST OF THE CONVECTION SOUTH OF I-16 THIS AFTERNOON...ESPECIALLY NEAR THE ALTAMAHA RIVER. 2. ADJUSTED SKY COVER PER GOING SATELLITE TRENDS. IT NOW APPEARS A GOOD PORTION OF THE AREA WILL INITIALIZE WITH MOSTLY SUNNY SKIES THIS MORNING...ESPECIALLY IN THE BEAUFORT-SAVANNAH-LUDOWICI CORRIDOR. 3. RAISED HIGH TEMPERATURES BY 1-2 DEGREES FOR MOST AREAS SINCE A GOOD BIT OF SUN WILL OCCUR THIS MORNING AND TEMPERATURES ARE STARTING OUT A TAD HIGHER THAN EXPECTED EARLIER THIS MORNING. SUBTLE CHANGES ARE ONGOING IN THE ATMOSPHERE THIS MORNING WHICH WILL HAVE SOME IMPACTS ON THE EVENTUAL CONVECTIVE PATTERN TODAY. THE REGION WILL REMAIN IN THE FAMILIAR UPPER AIR CONFIGURATION FEATURING DEEP LAYERED HIGH PRESSURE CENTERED WELL OFFSHORE AND A TROUGH OF LOW PRESSURE LINGERING ACROSS THE SOUTHERN MISSISSIPPI VALLEY. THE UPPER TROUGH IS FORECAST TO PROPAGATE SLOWLY EAST WITH A LOBE OF VORTICITY EJECTING EAST ACROSS THE MIDLANDS AND UPSTATE DURING PEAK HEATING. THIS FEATURE COUPLED WITH HIGH PWATS AND DAYTIME HEATING WILL YIELD A DECENT AMOUNT OF SHOWERS/TSTMS ACROSS THE MIDLANDS AND POSSIBLY THE CSRA...ESPECIALLY THIS AFTERNOON. FARTHER SOUTH...MODELS SHOW A POCKET OF RELATIVELY LOWER MID- LEVEL THETA AIR MOVING ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THIS AFTERNOON. MORNING WATER VAPOR IMAGERY AND GOES SOUNDINGS ACROSS ALABAMA CONFIRM THIS POCKET OF DRY AIR EXISTS SO HAVE NO REASON TO BOUT ITS EXISTENCE. THIS LOWER THETA POCKET WILL LIKELY LIMIT THE COVERAGE OF SHOWER/TSTMS A BIT TODAY...ESPECIALLY WHEN COMPARED TO PREVIOUS DAYS. IN FACT...SOME OF THE GLOBAL MODELS SHOW VERY LITTLE IN THE WAY OF TSTM ACTIVITY FIRING TODAY. THE HIGHER RESOLUTION MODELS ARE LIKELY MORE REALISTIC DEPICTING CONVECTIVE CLUSTERS PROPAGATING IN FROM THE SOUTHWEST LATER THIS AFTERNOON AND AFFECTING SOUTHEAST GEORGIA OR MOVING IN FROM THE EASTERN MIDLANDS BY THIS EVENING AND IMPACTING SOUTHERN SOUTH CAROLINA. PWATS ARE FORECAST TO LOWER BELOW 2 INCHES LATER TODAY...BUT LOCALIZED FLOODING WILL REMAIN A CONCERN. OPTED TO STAY ON THE LOWER SIDE OF THE GUIDANCE ENVELOP FOR HIGH TEMPERATURES AS EXTENSIVE CLOUD COVER AND SOME CONVECTION WILL LIKELY LIMIT TEMPERATURES SOMEWHAT. HIGHS WILL RANGE FROM THE UPPER 80S INLAND TO THE MID 80S AT THE COAST. IF CLOUDS THIN MORE THAN EXPECTED...HIGHS COULD SOAR INTO THE LOWER 90S AS SUGGESTED BY SOME ENSEMBLE MEMBERS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... TONIGHT...CONVECTION WILL GRADUALLY DISSIPATE THIS EVENING WITH DRY CONDITIONS PREVAILING OVERNIGHT. IT WILL REMAIN MOSTLY CLOUDY WITH LOTS OF DEBRIS CLOUDINESS IN PLACE. LOWS WILL RANGE FROM THE LOWER 70S INLAND TO THE MID-UPPER 70S AT THE COAST. TUESDAY AND WEDNESDAY...AN UPPER LEVEL TROUGH WILL AMPLIFY ALONG THE EAST COAST INTO THE MID WEEK PERIOD...WITH VARIOUS SHORTWAVES SHIFTING INTO THE REGION WITHIN WEST/NORTHWEST MID AND UPPER LEVEL FLOW. A WEAKENING COLD FRONT WILL ALSO BE APPROACHING FROM THE NORTHWEST AND SLIPPING TOWARD THE FORECAST AREA BY LATE WEDNESDAY...EMBEDDED WITHIN THE AXIS OF A SURFACE TROUGH DRIFTING TOWARD THE COASTLINE. CONVECTIVE COVERAGE...ALONG WITH THE POTENTIAL FOR HEAVY RAIN AND/OR SEVERE WEATHER...APPEARS HIGHLY DEPENDENT ON THE TIMING AND STRENGTH OF THE SERIES OF SHORTWAVES IMPACTING THE SOUTHEAST STATES THROUGH THE PERIOD. NUMERICAL MODEL SOLUTIONS SHOW NOTABLE VARIABILITY IN THEIR DEPICTION OF THIS ENERGY ALOFT...INCLUDING AREAS OF NEGATIVE VORTICITY ADVECTION THAT COULD LIMIT COVERAGE AT TIMES. DUE TO THIS UNCERTAINTY...HAVE LEANED TOWARD MORE CONSERVATIVE POPS TUESDAY AND WEDNESDAY. WILL CONTINUE TO HIGHLIGHT THE AFTERNOON AND EARLY EVENING PERIODS FOR BEST COVERAGE OVER LAND...WITH POPS GENERALLY PEAKING IN THE 30 TO 40 PERCENT RANGE. SHOWERS/THUNDERSTORMS SHOULD DIMINISH ACROSS LAND AREAS OVERNIGHT...WHILE THE MARINE ZONES EXPERIENCE AN INCREASE IN ACTIVITY THROUGH THE EARLY MORNING HOURS. PRECIPITABLE WATER WILL FALL BELOW 2 INCHES AND RANGE WITHIN MORE SEASONAL VALUES FOR LATE JULY. HEAVY RAIN POTENTIAL WILL BE REDUCED SLIGHTLY AS A RESULT...YET THE SUBSEQUENTLY DRIER MID LEVEL AIR AND INCREASE IN LAPSE RATES SUGGEST A HIGHER POTENTIAL FOR THE STRONGEST THUNDERSTORMS TO PRODUCE DOWNBURST WINDS. ALTHOUGH ORGANIZED SEVERE WEATHER IS STILL NOT EXPECTED AT THIS TIME...THERE IS A SMALL RISK FOR ISOLATED STORMS ENHANCED BY MESOSCALE BOUNDARY INTERACTIONS TO INTENSIFY TO SEVERE THRESHOLDS...WITH THE MAIN HAZARD BEING DAMAGING WIND GUSTS. THURSDAY...THE WEAKENING COLD FRONT WILL CONTINUE TO SLIP SOUTHEAST INTO THE FORECAST AREA...AS A DECENT WAVE OF LOW PRESSURE DEVELOPS ALONG THE BOUNDARY AND DRIFTS ACROSS THE SOUTHEAST COAST. THE AXIS OF THE STRONGEST IN THE SERIES OF SHORTWAVES WILL BE JUST UPSTREAM BY SUNSET...PROVIDING ADDITIONAL FORCING FOR ASCENT ACROSS THE REGION. DEEP MOISTURE WILL SURGE IN RESPONSE TO BOTH THE UPPER LEVEL ENERGY AND LOW LEVEL CONVERGENCE ALONG THE LINGERING FRONT. THE BEST CONVECTIVE COVERAGE OF THE SHORT TERM PERIOD COULD OCCUR THURSDAY AFTERNOON AS A RESULT. HEAVY RAIN COULD AGAIN BECOME A CONCERN CONSIDERING RISING PRECIPITABLE WATER VALUES. EXPECT LITTLE DAY TO DAY CHANGE IN TEMPERATURES THROUGH MID TO LATE WEEK. HAVE INDICATED HIGHS REACHING THE LOWER 90S EACH AFTERNOON AWAY FROM THE LOCALLY COOLER COASTLINE. LOW TEMPERATURES WILL GENERALLY FALL INTO THE LOW TO MID 70S INLAND. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... THE MAIN SHORTWAVE TROUGH WILL SHIFT INTO THE ATLANTIC LATE THURSDAY INTO FRIDAY...WITH A LESS AMPLIFIED UPPER LEVEL PATTERN PREVAILING THROUGH AT LEAST SATURDAY. THE LINGERING COLD FRONT WILL STALL AND EVENTUALLY DISSIPATE OVER THE SOUTHEAST STATES...WHILE UPPER RIDGING BRIEFLY ATTEMPTS TO BUILD BACK INTO THE REGION FROM THE SOUTH. WILL INDICATE MORE SEASONAL PRECIPITATION COVERAGE FRIDAY AND SATURDAY...WITH ISOLATED TO SCATTERED SHOWER/THUNDERSTORM ACTIVITY FOCUSED ALONG AND INLAND OF THE SEABREEZE EACH AFTERNOON/EARLY EVENING. THERE IS RATHER SIGNIFICANT DISAGREEMENT BETWEEN MEDIUM RANGE MODELS REGARDING THE STRENGTH OF ANOTHER UPPER TROUGH RAPIDLY MOVING INTO THE REGION SUNDAY AND MONDAY. PREFER TO MAINTAIN SOMEWHAT GENERIC RAIN CHANCES PEAKING IN THE 30 PERCENT RANGE EARLY NEXT WEEK UNTIL BETTER MODEL CONSISTENCY IS EVIDENT. HIGH TEMPERATURES WILL REACH THE LOWER 90S AWAY FROM THE COASTLINE EACH AFTERNOON. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... KCHS...THE EASTERN EDGE OF A LOW CLOUD BANK HAS BRUSHED TERMINAL. SATELLITE DATA AND RAP SOUNDINGS SUGGEST HIGH END IFR/LOW END MVFR CIGS WILL LINGER THROUGH ABOUT 14Z THEN RETURN TO VFR. BEST TSTM CHANCES LOOK TO REMAIN WELL SOUTH OF KCHS TODAY...ALTHOUGH AN ISOLATED TSTM COULD STILL OCCUR. WILL KEEP ALL MENTION OF TSRA OUT OF THE KCHS TAF FOR NOW. KSAV...LOW CLOUDS LOOK TO REMAIN WEST OF THE TERMINAL THIS MORNING. HIGH RESOLUTION MODEL GUIDANCE SUGGEST TSTMS WILL MOVE IN FROM THE SOUTHWEST LATER THIS AFTERNOON AND POSSIBLY AFFECT THE TERMINAL. TIMING/COVERAGE IS STILL A BIT UNCERTAIN THIS FAR OUT. WILL CARRY A TEMPO GROUP FROM 20-23Z FOR 4SM -TSRA BR BKN040CB TO COVER FOR NOW. FURTHER REFINEMENTS WILL BE NEEDED AS THE DAY PROGRESSES. SHOWERS/TSTMS SHOULD QUICKLY DISSIPATE THIS EVENING THUS ENDING THE RISK FOR TSTM IMPACTS. EXTENDED AVIATION OUTLOOK...LITTLE CHANGE IN THE PATTERN THROUGH THURSDAY...WITH MAINLY DIURNAL CONVECTION AND THE CHANCE FOR LATE NIGHT/EARLY MORNING STRATUS. THIS WILL RESULT IN PERIODIC FLIGHT RESTRICTIONS THROUGH THE PERIOD. && .MARINE... TODAY AND TONIGHT...SOMEWHAT ELEVATED WINDS WILL REMAIN IN PLACE TODAY WITH SPEEDS GENERALLY 15-20 KT...EXCEPT CLOSER TO 15 KT IN THE CHARLESTON HARBOR. SEAS WILL RANGE FROM 2-4 FT NEARSHORE WATERS AND 4-5 FT OFFSHORE WATERS. ATTM IT APPEARS BOTH WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. SIMILAR CONDITIONS ARE EXPECTED TONIGHT. TUESDAY AND WEDNESDAY...THE COASTAL WATERS WILL REMAIN BETWEEN THE SUB-TROPICAL ATLANTIC RIDGE TO THE SOUTH/SOUTHEAST...WHILE A PERSISTENT TROUGH OF LOW PRESSURE LINGERS INLAND. THE PRESSURE GRADIENT WILL BE UNSEASONABLY ENHANCED AS A RESULT...SUPPORTING WIND SPEEDS ABOVE NORMAL FOR LATE JULY. EXPECT WINDS TO PEAK AT 15 TO 20 KT THROUGH THE PERIOD...WITH OCCASIONAL GUSTS UP TO 25 KT. SMALL CRAFT ADVISORIES DO NOT APPEAR NECESSARY AT THIS TIME DUE TO THE INFREQUENCY OF HIGHER GUSTS. DIRECTIONS WILL BE MAINLY SOUTHWEST...VEERING A LITTLE AT NIGHT AND BACKING SOME DURING THE DAY WITHIN SEABREEZE CIRCULATIONS. SEAS WILL BE HELD UNDER 5 FT. MARINERS ARE ADVISED THAT ISOLATED SHOWERS AND THUNDERSTORMS COULD BECOME STRONG...WITH FREQUENT LIGHTNING AND HEAVY RAIN. ISOLATED STORMS COULD ALSO PRODUCE WIND GUSTS IN EXCESS OF 35 KT...AND SPECIAL MARINE WARNINGS MAY BECOME NECESSARY. CHECK NATIONAL WEATHER SERVICE FORECASTS AND NOAA WEATHER RADIO ALL HAZARDS BEFORE AND DURING ANY NAVIGATION INTO THE COASTAL WATERS. THURSDAY AND FRIDAY...THE PRESSURE GRADIENT WILL WEAKEN CONSIDERABLY LATE IN THE WEEK...AS THE INLAND TROUGH DRIFTS TOWARD THE COAST AND THE COLD FRONT STALLS INLAND. LIGHT WINDS COULD ACTUALLY BECOME VARIABLE AT TIMES...GENERALLY CAPPED NO HIGHER THAN 10 KT. OUTSIDE OF ANY CONVECTION...WINDS AND SEAS WILL BE WELL BELOW ANY SMALL CRAFT CONDITIONS. && .TIDES/COASTAL FLOODING... THE PERIGEAN SPRING TIDES WILL PERSIST TODAY SO ONLY SMALL POSITIVE TIDAL DEPARTURES MAY PRODUCE MINOR COASTAL FLOODING. SHOULD ANY SHALLOW SALT WATER COASTAL FLOODING OCCUR THE MOST LIKELY AREAS ARE CHARLESTON AND COASTAL COLLETON COUNTIES DURING THE EVENING HIGH TIDES THROUGH WEDNESDAY. IT IS IN THESE AREAS WHERE THE SMALLEST TIDAL DEPARTURES ARE REQUIRED FOR THE ISSUANCE OF AN ADVISORY. WE HAVE MAINTAINED MENTION OF THIS POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST/WMS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
625 AM EDT MON JUL 22 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE AT THE SURFACE AND ALOFT WILL PREVAIL ALONG THE EAST COAST THROUGH MID WEEK. A WEAKENING COLD FRONT WILL APPROACH FROM THE NORTHWEST LATE WEDNESDAY THROUGH THURSDAY... STALLING NEAR THE AREA INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MADE A FEW CHANGES WITH THE EARLY MORNING UPDATE. 1. LOWERED POPS IN THE CHARLESTON TRI COUNTY AREA TO 40 PERCENT AND INCREASED POPS TO 70 PERCENT OVER PORTIONS OF LONG...MCINTOSH AND LIBERTY COUNTIES PER LATEST RUNS OF HIGH RESOLUTION MODELS. BOTH THE RAP AND H3R NOW FOCUS MOST OF THE CONVECTION SOUTH OF I-16 THIS AFTERNOON...ESPECIALLY NEAR THE ALTAMAHA RIVER. 2. ADJUSTED SKY COVER PER GOING SATELLITE TRENDS. IT NOW APPEARS A GOOD PORTION OF THE AREA WILL INITIALIZE WITH MOSTLY SUNNY SKIES THIS MORNING...ESPECIALLY IN THE BEAUFORT-SAVANNAH-LUDOWICI CORRIDOR. 3. RAISED HIGH TEMPERATURES BY 1-2 DEGREES FOR MOST AREAS SINCE A GOOD BIT OF SUN WILL OCCUR THIS MORNING AND TEMPERATURES ARE STARTING OUT A TAD HIGHER THAN EXPECTED EARLIER THIS MORNING. SUBTLE CHANGES ARE ONGOING IN THE ATMOSPHERE THIS MORNING WHICH WILL HAVE SOME IMPACTS ON THE EVENTUAL CONVECTIVE PATTERN TODAY. THE REGION WILL REMAIN IN THE FAMILIAR UPPER AIR CONFIGURATION FEATURING DEEP LAYERED HIGH PRESSURE CENTERED WELL OFFSHORE AND A TROUGH OF LOW PRESSURE LINGERING ACROSS THE SOUTHERN MISSISSIPPI VALLEY. THE UPPER TROUGH IS FORECAST TO PROPAGATE SLOWLY EAST WITH A LOBE OF VORTICITY EJECTING EAST ACROSS THE MIDLANDS AND UPSTATE DURING PEAK HEATING. THIS FEATURE COUPLED WITH HIGH PWATS AND DAYTIME HEATING WILL YIELD A DECENT AMOUNT OF SHOWERS/TSTMS ACROSS THE MIDLANDS AND POSSIBLY THE CSRA...ESPECIALLY THIS AFTERNOON. FARTHER SOUTH...MODELS SHOW A POCKET OF RELATIVELY LOWER MID- LEVEL THETA AIR MOVING ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THIS AFTERNOON. MORNING WATER VAPOR IMAGERY AND GOES SOUNDINGS ACROSS ALABAMA CONFIRM THIS POCKET OF DRY AIR EXISTS SO HAVE NO REASON TO BOUT ITS EXISTENCE. THIS LOWER THETA POCKET WILL LIKELY LIMIT THE COVERAGE OF SHOWER/TSTMS A BIT TODAY...ESPECIALLY WHEN COMPARED TO PREVIOUS DAYS. IN FACT...SOME OF THE GLOBAL MODELS SHOW VERY LITTLE IN THE WAY OF TSTM ACTIVITY FIRING TODAY. THE HIGHER RESOLUTION MODELS ARE LIKELY MORE REALISTIC DEPICTING CONVECTIVE CLUSTERS PROPAGATING IN FROM THE SOUTHWEST LATER THIS AFTERNOON AND AFFECTING SOUTHEAST GEORGIA OR MOVING IN FROM THE EASTERN MIDLANDS BY THIS EVENING AND IMPACTING SOUTHERN SOUTH CAROLINA. PWATS ARE FORECAST TO LOWER BELOW 2 INCHES LATER TODAY...BUT LOCALIZED FLOODING WILL REMAIN A CONCERN. OPTED TO STAY ON THE LOWER SIDE OF THE GUIDANCE ENVELOP FOR HIGH TEMPERATURES AS EXTENSIVE CLOUD COVER AND SOME CONVECTION WILL LIKELY LIMIT TEMPERATURES SOMEWHAT. HIGHS WILL RANGE FROM THE UPPER 80S INLAND TO THE MID 80S AT THE COAST. IF CLOUDS THIN MORE THAN EXPECTED...HIGHS COULD SOAR INTO THE LOWER 90S AS SUGGESTED BY SOME ENSEMBLE MEMBERS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... TONIGHT...CONVECTION WILL GRADUALLY DISSIPATE THIS EVENING WITH DRY CONDITIONS PREVAILING OVERNIGHT. IT WILL REMAIN MOSTLY CLOUDY WITH LOTS OF DEBRIS CLOUDINESS IN PLACE. LOWS WILL RANGE FROM THE LOWER 70S INLAND TO THE MID-UPPER 70S AT THE COAST. TUESDAY AND WEDNESDAY...AN UPPER LEVEL TROUGH WILL AMPLIFY ALONG THE EAST COAST INTO THE MID WEEK PERIOD...WITH VARIOUS SHORTWAVES SHIFTING INTO THE REGION WITHIN WEST/NORTHWEST MID AND UPPER LEVEL FLOW. A WEAKENING COLD FRONT WILL ALSO BE APPROACHING FROM THE NORTHWEST AND SLIPPING TOWARD THE FORECAST AREA BY LATE WEDNESDAY...EMBEDDED WITHIN THE AXIS OF A SURFACE TROUGH DRIFTING TOWARD THE COASTLINE. CONVECTIVE COVERAGE...ALONG WITH THE POTENTIAL FOR HEAVY RAIN AND/OR SEVERE WEATHER...APPEARS HIGHLY DEPENDENT ON THE TIMING AND STRENGTH OF THE SERIES OF SHORTWAVES IMPACTING THE SOUTHEAST STATES THROUGH THE PERIOD. NUMERICAL MODEL SOLUTIONS SHOW NOTABLE VARIABILITY IN THEIR DEPICTION OF THIS ENERGY ALOFT...INCLUDING AREAS OF NEGATIVE VORTICITY ADVECTION THAT COULD LIMIT COVERAGE AT TIMES. DUE TO THIS UNCERTAINTY...HAVE LEANED TOWARD MORE CONSERVATIVE POPS TUESDAY AND WEDNESDAY. WILL CONTINUE TO HIGHLIGHT THE AFTERNOON AND EARLY EVENING PERIODS FOR BEST COVERAGE OVER LAND...WITH POPS GENERALLY PEAKING IN THE 30 TO 40 PERCENT RANGE. SHOWERS/THUNDERSTORMS SHOULD DIMINISH ACROSS LAND AREAS OVERNIGHT...WHILE THE MARINE ZONES EXPERIENCE AN INCREASE IN ACTIVITY THROUGH THE EARLY MORNING HOURS. PRECIPITABLE WATER WILL FALL BELOW 2 INCHES AND RANGE WITHIN MORE SEASONAL VALUES FOR LATE JULY. HEAVY RAIN POTENTIAL WILL BE REDUCED SLIGHTLY AS A RESULT...YET THE SUBSEQUENTLY DRIER MID LEVEL AIR AND INCREASE IN LAPSE RATES SUGGEST A HIGHER POTENTIAL FOR THE STRONGEST THUNDERSTORMS TO PRODUCE DOWNBURST WINDS. ALTHOUGH ORGANIZED SEVERE WEATHER IS STILL NOT EXPECTED AT THIS TIME...THERE IS A SMALL RISK FOR ISOLATED STORMS ENHANCED BY MESOSCALE BOUNDARY INTERACTIONS TO INTENSIFY TO SEVERE THRESHOLDS...WITH THE MAIN HAZARD BEING DAMAGING WIND GUSTS. THURSDAY...THE WEAKENING COLD FRONT WILL CONTINUE TO SLIP SOUTHEAST INTO THE FORECAST AREA...AS A DECENT WAVE OF LOW PRESSURE DEVELOPS ALONG THE BOUNDARY AND DRIFTS ACROSS THE SOUTHEAST COAST. THE AXIS OF THE STRONGEST IN THE SERIES OF SHORTWAVES WILL BE JUST UPSTREAM BY SUNSET...PROVIDING ADDITIONAL FORCING FOR ASCENT ACROSS THE REGION. DEEP MOISTURE WILL SURGE IN RESPONSE TO BOTH THE UPPER LEVEL ENERGY AND LOW LEVEL CONVERGENCE ALONG THE LINGERING FRONT. THE BEST CONVECTIVE COVERAGE OF THE SHORT TERM PERIOD COULD OCCUR THURSDAY AFTERNOON AS A RESULT. HEAVY RAIN COULD AGAIN BECOME A CONCERN CONSIDERING RISING PRECIPITABLE WATER VALUES. EXPECT LITTLE DAY TO DAY CHANGE IN TEMPERATURES THROUGH MID TO LATE WEEK. HAVE INDICATED HIGHS REACHING THE LOWER 90S EACH AFTERNOON AWAY FROM THE LOCALLY COOLER COASTLINE. LOW TEMPERATURES WILL GENERALLY FALL INTO THE LOW TO MID 70S INLAND. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... THE MAIN SHORTWAVE TROUGH WILL SHIFT INTO THE ATLANTIC LATE THURSDAY INTO FRIDAY...WITH A LESS AMPLIFIED UPPER LEVEL PATTERN PREVAILING THROUGH AT LEAST SATURDAY. THE LINGERING COLD FRONT WILL STALL AND EVENTUALLY DISSIPATE OVER THE SOUTHEAST STATES...WHILE UPPER RIDGING BRIEFLY ATTEMPTS TO BUILD BACK INTO THE REGION FROM THE SOUTH. WILL INDICATE MORE SEASONAL PRECIPITATION COVERAGE FRIDAY AND SATURDAY...WITH ISOLATED TO SCATTERED SHOWER/THUNDERSTORM ACTIVITY FOCUSED ALONG AND INLAND OF THE SEABREEZE EACH AFTERNOON/EARLY EVENING. THERE IS RATHER SIGNIFICANT DISAGREEMENT BETWEEN MEDIUM RANGE MODELS REGARDING THE STRENGTH OF ANOTHER UPPER TROUGH RAPIDLY MOVING INTO THE REGION SUNDAY AND MONDAY. PREFER TO MAINTAIN SOMEWHAT GENERIC RAIN CHANCES PEAKING IN THE 30 PERCENT RANGE EARLY NEXT WEEK UNTIL BETTER MODEL CONSISTENCY IS EVIDENT. HIGH TEMPERATURES WILL REACH THE LOWER 90S AWAY FROM THE COASTLINE EACH AFTERNOON. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... TO BE ISSUED. EXTENDED AVIATION OUTLOOK...LITTLE CHANGE IN THE PATTERN THROUGH THURSDAY...WITH MAINLY DIURNAL CONVECTION AND THE CHANCE FOR LATE NIGHT/EARLY MORNING STRATUS. THIS WILL RESULT IN PERIODIC FLIGHT RESTRICTIONS THROUGH THE PERIOD. && .MARINE... TODAY AND TONIGHT...SOMEWHAT ELEVATED WINDS WILL REMAIN IN PLACE TODAY WITH SPEEDS GENERALLY 15-20 KT...EXCEPT CLOSER TO 15 KT IN THE CHARLESTON HARBOR. SEAS WILL RANGE FROM 2-4 FT NEARSHORE WATERS AND 4-5 FT OFFSHORE WATERS. ATTM IT APPEARS BOTH WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. SIMILAR CONDITIONS ARE EXPECTED TONIGHT. TUESDAY AND WEDNESDAY...THE COASTAL WATERS WILL REMAIN BETWEEN THE SUB-TROPICAL ATLANTIC RIDGE TO THE SOUTH/SOUTHEAST...WHILE A PERSISTENT TROUGH OF LOW PRESSURE LINGERS INLAND. THE PRESSURE GRADIENT WILL BE UNSEASONABLY ENHANCED AS A RESULT...SUPPORTING WIND SPEEDS ABOVE NORMAL FOR LATE JULY. EXPECT WINDS TO PEAK AT 15 TO 20 KT THROUGH THE PERIOD...WITH OCCASIONAL GUSTS UP TO 25 KT. SMALL CRAFT ADVISORIES DO NOT APPEAR NECESSARY AT THIS TIME DUE TO THE INFREQUENCY OF HIGHER GUSTS. DIRECTIONS WILL BE MAINLY SOUTHWEST...VEERING A LITTLE AT NIGHT AND BACKING SOME DURING THE DAY WITHIN SEABREEZE CIRCULATIONS. SEAS WILL BE HELD UNDER 5 FT. MARINERS ARE ADVISED THAT ISOLATED SHOWERS AND THUNDERSTORMS COULD BECOME STRONG...WITH FREQUENT LIGHTNING AND HEAVY RAIN. ISOLATED STORMS COULD ALSO PRODUCE WIND GUSTS IN EXCESS OF 35 KT...AND SPECIAL MARINE WARNINGS MAY BECOME NECESSARY. CHECK NATIONAL WEATHER SERVICE FORECASTS AND NOAA WEATHER RADIO ALL HAZARDS BEFORE AND DURING ANY NAVIGATION INTO THE COASTAL WATERS. THURSDAY AND FRIDAY...THE PRESSURE GRADIENT WILL WEAKEN CONSIDERABLY LATE IN THE WEEK...AS THE INLAND TROUGH DRIFTS TOWARD THE COAST AND THE COLD FRONT STALLS INLAND. LIGHT WINDS COULD ACTUALLY BECOME VARIABLE AT TIMES...GENERALLY CAPPED NO HIGHER THAN 10 KT. OUTSIDE OF ANY CONVECTION...WINDS AND SEAS WILL BE WELL BELOW ANY SMALL CRAFT CONDITIONS. && .TIDES/COASTAL FLOODING... THE PERIGEAN SPRING TIDES WILL PERSIST TODAY SO ONLY SMALL POSITIVE TIDAL DEPARTURES MAY PRODUCE MINOR COASTAL FLOODING. SHOULD ANY SHALLOW SALT WATER COASTAL FLOODING OCCUR THE MOST LIKELY AREAS ARE CHARLESTON AND COASTAL COLLETON COUNTIES DURING THE EVENING HIGH TIDES THROUGH WEDNESDAY. IT IS IN THESE AREAS WHERE THE SMALLEST TIDAL DEPARTURES ARE REQUIRED FOR THE ISSUANCE OF AN ADVISORY. WE HAVE MAINTAINED MENTION OF THIS POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST/WMS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1025 AM EDT MON JUL 22 2013 .UPDATE... ISSUED AT 1025 AM EDT MON JUL 22 2013 13Z SFC ANALYSIS SHOWS A DEVELOPING AREA OF LOW PRESSURE MOVING INTO THE OHIO VALLEY. THIS DEVELOPMENT IS OCCURRING DUE TO AN INBOUND AND SHARPENING 500 MB SHORT WAVE THAT WILL CROSS NORTHERN KENTUCKY LATER TODAY. AS SUCH...IT IS ALSO BRINGING WITH IT A LARGE CLUSTER OF MAINLY MODERATE SHOWERS ALONG WITH A COUPLE OF EMBEDDED THUNDERSTORMS. THE RAIN AREA IS POISED TO ENTER OUR CWA AND PROGRESS FROM WEST TO EAST THROUGH THE REST OF THE MORNING. THE LATEST HRRR DOES SHOW THIS AREA BREAKING UP TOWARD NOON AND MORE SCATTERED CONVECTION DEVELOPING THROUGHOUT EAST KENTUCKY... THEREAFTER. EXPECT THIS SECONDARY CONVECTION...TAPPING INTO HIGH PW AIR IN PLACE...TO HAVE THE BEST CHANCE OF PRODUCING EXCESSIVE RAINS...TRAINING...AND THE POTENTIAL FOR LOCALIZED FLASH FLOODING. HAVE UPDATED THE GRIDS TO REFLECT THIS TYPE OF EVOLUTION TO THE POPS...WX...AND QPF. ALSO...BUMPED UP TEMPS IN THE EAST A NOTCH DUE TO A DECENT SUNNY PATCH MOVING THROUGH ATTM AHEAD OF THE INBOUND MASS OF SHOWERS. MEANWHILE...TOOK DOWN THE MAX TEMPS IN THE WEST A TAD FOR THE OPPOSITE REASON. OTHERWISE...THE THREAT FOR DOWNPOURS LOOKS GOOD FOR MOST OF THE REGION SO WILL CONTINUE THE FFA AND MENTION OF LOCALLY HEAVY RAIN IN THE ZONES/HWO THROUGH THE EVENING. FOR TONIGHT...WILL HAVE TO LOOK CLOSELY AT THE POTENTIAL FOR DENSE FOG IF WE MANAGE TO GET MUCH CLEARING AFTER THE RAINS OF TODAY. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 753 AM EDT MON JUL 22 2013 UPSTREAM RADARS SHOW A LARGE CLUSTER OF SHOWERS AND STORMS MAKING A BEELINE TOWARD EAST KENTUCKY. AS A RESULT...WE NUDGED POPS UP INTO THE CATEGORICAL RANGE FOR ALL BUT OUR EASTERNMOST COUNTIES AS RECENT HRRR RUNS SHOW THE SHOWERS BREAKING UP SOME AS THEY HEAD EAST OF JKL. UPDATE ISSUED AT 655 AM EDT MON JUL 22 2013 MODIFIED THE FORECAST GRIDS TO REFLECT SLOWER ONSET OF PRECIPITATION EARLY THIS MORNING. ALSO ISSUED AN UPDATE TO THE FLASH FLOOD WATCH. THE NEW ZONES WILL BE ISSUED SHORTLY. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 310 AM EDT MON JUL 22 2013 MODELS IN PRETTY GOOD AGREEMENT ON THE OVERALL WEATHER PATTERN FOR THE NEXT COUPLE OF DAY. CONSENSUS VIEW IS FOR WIDESPREAD SHOWERS AND STORMS TO DEVELOP EARLY THIS MORNING AND PERSIST THROUGH THE END OF THE DAY ON TUESDAY. THE PRIMARY CONCERN WILL BE LOCALLY HEAVY RAINFALL AND FLOODING. WITH A DEEP LAYER OF MOISTURE IN THE ATMOSPHERE AND WEAK MIDDLE AND UPPER LEVEL WINDS...ANY STORMS THAT FORM WILL BE SLOW MOVING AND WILL HAVE THE POTENTIAL PRODUCE HEAVY RAINFALL OVER VERY LOCALIZED AREAS...WHICH COULD LEAD TO FLASH FLOODING. HIGH TEMPERATURES TODAY AND TOMORROW WILL BE SLIGHTLY BELOW NORMAL...DUE TO THE INFLUENCE OF WIDESPREAD CLOUD COVER AND SHOWER AND STORM ACTIVITY. A FLASH FLOOD WATCH REMAINS IN EFFECT FOR ALL OF EASTERN KENTUCKY THROUGH MONDAY EVENING. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON JUL 22 2013 LONGWAVE TROUGH NOW BECOMING ESTABLISHED OVER THE EASTERN U.S. WILL REMAIN IN PLACE THROUGH THE LONG TERM PERIOD. AT THE SURFACE...A COLD FRONT WILL SLIP TO OUR SOUTH TUESDAY NIGHT AND WEDNESDAY WITH HIGH PRESSURE BUILDING IN BEHIND. WHILE THE DEEPER MOISTURE WILL BE TO OUR SOUTH BY TUESDAY NIGHT...THE FRONT WILL LIKELY KICK OFF ISOLATED TO SCATTERED SHOWERS/STORMS AS IT PASSES. THE HIGH PRESSURE SYSTEM WILL THEN USHER IN A MUCH DRIER AIR MASS FOR THURSDAY AND FRIDAY. IN FACT...IT APPEARS DEWPOINTS MAY EVEN TUMBLE AS LOW AS THE UPPER 50S BY THURSDAY AFTERNOON...WHICH WILL FEEL VERY NICE AFTER THE RECENT PROLONGED BOUT OF 70 DEGREE DEWPOINTS. FORECASTER CONFIDENCE THEN FALLS AS WE HEAD INTO THE WEEKEND. THE UPPER LEVEL TROUGH WILL DIG BACK IN AFTER A BRIEF RELAXATION FORCING A SURFACE FRONT SOUTHWARD INTO THE OHIO VALLEY. THE 22/00Z ECMWF WANTS TO HOLD A PIECE OF THE UPPER TROUGH BACK OVER THE PLAINS... WHILE THE 22/00Z GFS/GEM/UKMET DO NOT. THIS RESULTS IN A WETTER SOLUTION IN THE GFS/GEM/UKMET MODELS WHILE THE ECMWF IS SLOWER TO BRING IN ANY PRECIP. AS SUCH...WILL TREND BACK A LITTLE WITH POPS TO REFLECT THE ADDED UNCERTAINTY BUT STILL OFFER SCATTERED SHOWERS AND STORMS THROUGHOUT THE WEEKEND. DAYTIME HIGHS WILL CHANGE LITTLE THROUGH THE PERIOD...REACHING THE LOW TO MID 80S EACH DAY. OVERNIGHT LOWS WILL RESPOND TO THE FALLING DEWPOINTS LATE IN THE WEEK...FALLING FROM THE MID TO UPPER 60S TUESDAY NIGHT BACK INTO THE UPPER 50S TO LOW 60S THURSDAY NIGHT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 753 AM EDT MON JUL 22 2013 PRECIPITATION ONSET THIS MORNING WILL OCCUR BETWEEN 1430Z AND 16Z AT THE TAF SITES AS A LARGE CLUSTER OF SHOWERS AND STORMS PROGRESSES EASTWARD ACROSS THE REGION. EXPECTING MVFR CONDITIONS TO PREVAIL AT THE TAF SITES ONCE THE RAIN BEGINS TO FALL. THE CLUSTER OF SHOWERS WILL SHIFT EAST DURING THE AFTERNOON WITH A LESS WELL DEFINED THREAT FOR SHOWERS AND STORMS FROM LATE AFTERNOON INTO THE EVENING HOURS. LOW CLOUDS AND FOG WILL THEN BECOME A HAZARD TO AVIATION LATE TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...ABE AVIATION...AR/ABE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
643 AM EDT MON JUL 22 2013 ...Updated Aviation Discussion... .FORECAST UPDATE... Issued at 640 AM EDT Mon Jul 22 2013 A solid line of showers has formed along a Theta-E ridge running from NW TN to FTK. A broad meso has formed along that line and is getting ready to move into our southwest forecast area. KHPX radar indicates a nice low-level jet, with winds of 35-40 knots at ~2500 feet. Tried blending ongoing radar trends with RAP forecasts for this Theta-E ridge over the next couple of hours to get a PoP forecast. Updated products are out. && .SHORT TERM (Today through Tuesday)... Issued at 315 AM EDT Sun Jul 21 2013 Pronounced shortwave trough, centered now along the northern MO/IL border will move into our region today. Combined with a tropical airmass in place, and we should see another round of showers and storms this morning into the afternoon. Seeing one line of storms forming over the MO/AR border into western KY and another one closer to a stationary front to our north, along the central IL/IN border. With additional storms in the forecast, have decided to lift a flash flood watch for a portion of our forecast area. The Bluegrass has the lowest flash flood guidance, with 3-hour guidance between 1.5 and 2 inches. Areal average QPF for that region is around an inch, but it easily could be higher with any slow-moving heavy storms. Airmass looks too tropical for severe weather, though we do look to have a weak low moving up the Ohio Valley ahead of the upper level feature, so will have to watch for some rotation in any storms that form. We should see a break in the precip tonight, but the airmass does not dry out until after this period, so cannot rule out additional isolated storms. Another wave looks to come across the area Tuesday, bringing enhanced rain chances once more. Coverage should be more limited than today, but soundings favor a better chance for stronger storms, with gusty winds and hail as the main threats. Temperatures today will depend on how quick the precip exits our region this afternoon. Have gone with higher values over the west, mid 80s compared with around 80 for the east. Temperatures tonight should be similar to this morning, with no real change in airmass. Readings should warm back into the upper 80s for Tuesday. .LONG TERM (Tuesday Night through Sunday)... Issued at 300 AM EDT Mon Jul 22 2013 Longwave 500mb upper air pattern early Wednesday will feature a broad ridge centered over the Intermountain West and a robust trough centered over the Great Lakes. Northwest flow will influence the Lower Ohio Valley. Ultimately, this pattern will bring pleasant, seasonably cool weather and relatively low dewpoints, especially for the period Wednesday through Friday. Several weak waves may move southeast across the Lower Ohio Valley Tuesday through Saturday. The first will cross the Ohio River Tuesday evening. High pressure over the upper midwest will build in behind a cold front that will move across the Commonwealth during the early morning hours Wednesday. Scattered convection will likely end from the north to the south during the morning hours Wednesday as drier air arrives from the northwest. Think that Wednesday afternoon will stay dry with noticeably less humid conditions. Northwesterly winds behind this front will lower dewpoints into the upper 50s by Wednesday evening. High pressure will build across the northern Ohio Valley Thursday and continue through Friday. Expect mostly clear skies with comfortable nights. Highs will stay in the mid 80s with lows well down into the 60s. The proximity of the surface high to our north will lead to light northeasterly to easterly winds through early Saturday. For several days now, long range guidance has advertised a quick return of moisture ahead of an upper wave on Saturday. Showers and storms may approach as early as Saturday morning and continue during the day Saturday just ahead of a progressive 500mb trough. Temperatures still will stay relatively mild Saturday and Sunday, with highs in the 80s and upper 60s at night. Expect clearing Sunday with dry conditions. && .AVIATION (12Z TAF Update)... Issued at 645 AM EDT Mon Jul 22 2013 Very moist atmosphere remains in place ahead of an upper level disturbance forecast to move through the region this afternoon. Have tried to time storms based on RAP forecasts for now, with periods of at least MVFR conditions. Rain chances should become more limited when that trough comes through so have kept in some VFR cigs by mid/late afternoon with no storms. We may see some light fog by the end of the period, given no real change in airmass and muggy conditions, but will leave out of the forecast for now to keep the number of lines in the TAFs down. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ036-037-041>043- 048-049-057. $$ Update...........RJS Short Term.......RJS Long Term........JSD Aviation.........RJS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1200 PM EDT MON JUL 22 2013 .SYNOPSIS... ISSUED AT 407 AM EDT MON JUL 22 2013 HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO NORTHERN MICHIGAN. && .UPDATE... ISSUED AT 1200 PM EDT MON JUL 22 2013 MID MORNING SURFACE ANALYSIS SHOWS 999MB LOW CENTER OVER NORTHWEST ONTARIO JUST NORTH OF THE BOUNDARY WATERS...TRAILING COLD FRONT EXTENDS BACK INTO SOUTHWEST MINNESOTA/EASTERN NEBRASKA WITH A WARM FRONT EXTENDING SOUTHEAST ACROSS CENTRAL UPPER/NORTHWEST LOWER MICHIGAN. MOISTURE HAS BEEN INCREASING ACROSS MICHIGAN OVER THE LAST 24 HOURS...PRECIPITABLE WATER ON 12Z APX SOUNDING HAS DOUBLED SINCE 12Z SUNDAY (1.07 INCHES). STRAIGHT MODIFICATION OF THE SOUNDING MIXING TO 800MB (78/58) ONLY YIELDS AROUND 400J/KG MLCAPE BUT DEW POINTS HAVE BEEN CLIMBING INTO THE LOWER 60S...AND TEMPERATURES ALREADY IN THE MID/UPPER 70S. SO AN 81/63 PARCEL PUSHES MLCAPE VALUES ABOVE 1100J/KG. ALREADY GETTING SOME CU DEVELOPING EAST OF AN LDM-PZQ LINE...AND A FEW RADAR RETURNS POPPING UP ALONG THE THUMB. BASIC FORECAST IDEAS WILL REMAIN INTACT WITH CONVECTION POPPING UP THIS AFTERNOON...WITH 1000-1500J/KG MLCAPE EXPECTED. WILL KEEP NORTHWEST LOWER SHORELINE COUNTIES DRY WITH AN ONSHORE BREEZE/LAKE SHADOW. DEEP LAYER SHEAR NOT STRONG TODAY...SOME DECENT VEERING OF WINDS ALOFT BUT NOT MUCH SPEED SHEAR (0-6KM BULK SHEAR VALUES 20-30KTS). HAVE BEEN ADJUSTING THE TIMING A BIT GIVEN CURRENT TRENDS. FORECAST HIGHS UPPER 70S-MID 80S LOOK FINE. UPDATE ISSUED AT 638 AM EDT MON JUL 22 2013 ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END CHANCE FOR A SEVERE STORM OR TWO. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 407 AM EDT MON JUL 22 2013 INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT. OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF 07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE OF LAKE MICHIGAN. CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN. THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z. INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY AREAS. THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z. BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD 1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE BOUNDARY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON JUL 22 2013 THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF THE NEXT WORK WEEK. TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD. TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW WISCONSIN. THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE. TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT. REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND LOWER 70S FOR THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 638 AM EDT MON JUL 22 2013 A WARM FRONT IS LIFTING THROUGH NRN MICHIGAN EARLY THIS MORNING...AND THE EARLIER ASSOCIATED LIGHT RAIN SHOWERS/SPRINKLES HAVE EXITED NE LOWER. COULD STILL SEE A FEW LIGHT SHOWERS POP OFF THROUGH MID MORNING...BUT A WEDGE OF DRIER AIR HAS FILLED IN OVER THE REGION. LOW LEVEL MOISTURE WILL ADVECT NORTHWARD AND INTO NRN MICHIGAN THROUGH THE DAY...AND THE SUNSHINE SEEN THIS MORNING WILL HELP DESTABILIZE THE ATMOSPHERE ENOUGH TO WHERE SCATTERED SHOWERS AND A FEW STORMS ARE EXPECTED TO POP OFF AS EARLY AS 15Z...BUT MORE SO THIS AFTERNOON. THE BEST CHANCE FOR POSSIBLE BRIEF MVFR CIGS/VSBYS WILL BE AT APN...WITH THE EXPECTED DEVELOPMENT JUST EAST OF PLN/TVC/MBL. THIS CONVECTION WILL DIE OFF INTO THE EVENING...BUT UPSTREAM THERE IS ANOTHER SHORTWAVE TROUGH ALOFT AND ASSOCIATED COLD FRONT THAT WILL BE PUSHING THROUGH OVERNIGHT. THESE FEATURES WILL HAVE A BETTER CHANCE FOR BRINGING SHOWERS AND STORMS TO ALL TAF SITES. THERE IS A CHANCE THAT A STORM OVERNIGHT WILL BE ABLE TO BECOME SEVERE WITH THE OUTSIDE POTENTIAL FOR DAMAGING WINDS AND LARGE HAIL. CHANCES WAY TOO SMALL FOR ANY ONE LOCATION TO ACTUALLY SEE THIS SEVERITY...MUCH LESS GET RAINED ON. AT MOST...WILL INTRO A VCTS/CB GROUP. DEVELOPING GUSTY SW WINDS THIS AFTERNOON WILL SHIFT OUT OF THE NW LATE IN THE TAF PERIOD BEHIND THE COLD FRONT. && .MARINE... ISSUED AT 407 AM EDT MON JUL 22 2013 LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS. THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED. HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK... GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH THURSDAY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JPB SYNOPSIS...SD SHORT TERM...DL LONG TERM...SD AVIATION...SD MARINE...DL
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1110 AM EDT MON JUL 22 2013 LATEST UPDATE... UPDATE/MARINE .SYNOPSIS... ISSUED AT 330 AM EDT MON JUL 22 2013 A WARM FRONT WILL BRING A FEW SHOWERS AND THUNDERSTORMS LATER TODAY AND THEN A COLD FRONT WILL BRING MORE SCATTERED SHOWERS AND STORMS TONIGHT INTO TUESDAY. FAIR AND COOLER WEATHER WILL ARRIVE BY LATE TUESDAY AND LAST THROUGH THURSDAY. TEMPERATURES WILL AVERAGE NEAR NORMAL LATE IN THE WEEK THROUGH NEXT WEEKEND. && .UPDATE... ISSUED AT 1110 AM EDT MON JUL 22 2013 DROPPED MAXIMUM TEMPERATURES TODAY SLIGHTLY MAINLY SOUTH OF I-96 TO ACCOUNT FOR THE COOLING EFFECTS OF EXTENSIVE PRECIPITATION OVERNIGHT AND RESIDUAL CLOUD COVER. ALSO RAISED PRECIPITATION CHANCES EAST OF US-131 BASED ON HRRR MODEL GUIDANCE AND TO BETTER AGREE WITH SURROUNDING OFFICES. MAIN FORECAST CONCERN THIS AFTERNOON WILL BE PRECIPITATION CHANCES OVERNIGHT WITH THE APPROACHING COLD FRONT. UPDATE ISSUED AT 537 AM EDT MON JUL 22 2013 A COUPLE OF SHOWERS DEVELOPED IN THE PAST HR...ESPECIALLY NEAR LWA. WENT AND ADDED A RISK FOR A FEW EARLY MORNING SHOWERS PRIMARILY SOUTH OF A BIV TO LAN LINE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON) ISSUED AT 330 AM EDT MON JUL 22 2013 AFTER SOME LINGERING EARLY MORNING SHOWERS OVER OUR SE FCST AREA DRY WX IS ANTICIPATED FOR THE REST OF THE MORNING IN THE WAKE OF THE DEPARTING MCV THAT BROUGHT THE ROUND OF RAIN AND STORMS YESTERDAY EVENING AND OVERNIGHT. SOME WAA SHOWERS AND A FEW STORMS WILL DEVELOP THIS AFTERNOON. A FAIR AMOUNT OF SUN AND SSW WINDS WILL HELP TO BOOST MAX TEMPS INTO THE LOWER TO MIDDLE 80S ACROSS MOST OF OUR AREA TODAY. THE COLD FRONT WILL MOVE IN FROM THE NW TONIGHT AND BRING SCATTERED SHOWERS AND STORMS WHICH WILL LAST THROUGH ABOUT MIDDAY TUESDAY BEFORE THE FRONT CLEARS OUR AREA. A COOLER AND DRIER AIRMASS WILL ADVECT IN BEHIND THAT FRONT AND MAX TEMPS WEDNESDAY WILL ONLY REACH THE 70S. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM EDT MON JUL 22 2013 PATTERN IS LOOKING COOLER WITH TIME ESPECIALLY THIS WEEKEND. MODELS IN DECENT AGREEMENT IN SHOWING A COLD FRONT PUSHING THROUGH FRI NIGHT INTO SAT WITH A WAVE OF LOW PRESSURE FORMING ON IT OVER SOUTHERN LOWER MI. THIS SHOULD LEAD TO SHOWERS AND WITH INSTABILITY AROUND THUNDERSTORMS. IF THE NEW HIGH RES EURO IS CORRECT SAT COULD BE A RATHER WET DAY FOR THE AREA. NORTHERLY FLOW SETS UP BEHIND THE WAVE LEADING TO STRONG COLD AIR ADVECTION. 925 MB TEMPS FALL TO UNDER 10 DEG C 12Z SUN. IF THIS HAPPENS AND THE UPPER LOW DEVELOPS NORTH OF SUPERIOR AS SHOWN BY THE HIGH RES EURO ON SUN...LAKE ENHANCED MOISTURE MAY IMPACT THE FORECAST. I LOWERED TEMPERATURES OVER GUIDANCE FOR SAT NIGHT THROUGH SUN BASED ON THIS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 537 AM EDT MON JUL 22 2013 LIGHT RAIN SOUTH OF KAZO TRYING TO WORK NORTH AT THIS TIME. PRECIPITATION IS FALLING OUT OF MID LEVEL CLOUDS...SO VFR WEATHER EXPECTED EVEN IF THE RAIN DOES MOVE IN. THE LOW LEVELS ARE MOIST SO AN INCREASED RISK FOR MVFR/IFR EXISTS...BUT CONFIDENCE THAT IT WILL OCCUR IS TOO LOW TO ADD IT TO THE FORECAST. THE NEXT BATCH OF RAIN WITH POSSIBLE THUNDERSTORMS ARRIVES IN KMKG FIRST AROUND 04Z...THEN THE RAIN TRACKS SOUTHEAST FOR THE REMAINDER OF THE NIGHT. WE MAY SEE MVFR CONDITIONS WITH THIS RAIN LATER TONIGHT. THE IFR OR LOWER CONDITIONS CURRENTLY IN WI...ARE EXPECTED TO NOT REACH THE TAF SITES TODAY. && .MARINE... ISSUED AT 1110 AM EDT MON JUL 22 2013 LATEST OMR SHOWS WAVEHEIGHTS GENERALLY BELOW 2 FEET...ALTHOUGH 3 FEET WAS REPORTED AT GRAND HAVEN. AS NOTED IN THE PREVIOUS DISCUSSION...WINDS AND WAVES WILL INCREASE TODAY. ALTHOUGH A SMALL CRAFT ADVISORY IS NOT ANTICIPATED...WE WILL HAVE TO WATCH THE BEACH HAZARD POTENTIAL /PRIMARILY INCREASING LONGSHORE CURRENTS/ AS IT EVOLVES THIS AFTERNOON AND EVENING. && .HYDROLOGY... ISSUED AT 330 AM EDT MON JUL 22 2013 NO HYDRO ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...TJT SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MJS AVIATION...MJS HYDROLOGY...LAURENS MARINE...TJT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
703 AM EDT MON JUL 22 2013 .SYNOPSIS... ISSUED AT 407 AM EDT MON JUL 22 2013 HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO NORTHERN MICHIGAN. && .UPDATE... ISSUED AT 638 AM EDT MON JUL 22 2013 ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END CHANCE FOR A SEVERE STORM OR TWO. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 407 AM EDT MON JUL 22 2013 INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT. OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF 07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE OF LAKE MICHIGAN. CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN. THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z. INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY AREAS. THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z. BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD 1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE BOUNDARY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON JUL 22 2013 THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF THE NEXT WORK WEEK. TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD. TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW WISCONSIN. THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE. TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT. REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND LOWER 70S FOR THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 638 AM EDT MON JUL 22 2013 A WARM FRONT IS LIFTING THROUGH NRN MICHIGAN EARLY THIS MORNING...AND THE EARLIER ASSOCIATED LIGHT RAIN SHOWERS/SPRINKLES HAVE EXITED NE LOWER. COULD STILL SEE A FEW LIGHT SHOWERS POP OFF THROUGH MID MORNING...BUT A WEDGE OF DRIER AIR HAS FILLED IN OVER THE REGION. LOW LEVEL MOISTURE WILL ADVECT NORTHWARD AND INTO NRN MICHIGAN THROUGH THE DAY...AND THE SUNSHINE SEEN THIS MORNING WILL HELP DESTABILIZE THE ATMOSPHERE ENOUGH TO WHERE SCATTERED SHOWERS AND A FEW STORMS ARE EXPECTED TO POP OFF AS EARLY AS 15Z...BUT MORE SO THIS AFTERNOON. THE BEST CHANCE FOR POSSIBLE BRIEF MVFR CIGS/VSBYS WILL BE AT APN...WITH THE EXPECTED DEVELOPMENT JUST EAST OF PLN/TVC/MBL. THIS CONVECTION WILL DIE OFF INTO THE EVENING...BUT UPSTREAM THERE IS ANOTHER SHORTWAVE TROUGH ALOFT AND ASSOCIATED COLD FRONT THAT WILL BE PUSHING THROUGH OVERNIGHT. THESE FEATURES WILL HAVE A BETTER CHANCE FOR BRINGING SHOWERS AND STORMS TO ALL TAF SITES. THERE IS A CHANCE THAT A STORM OVERNIGHT WILL BE ABLE TO BECOME SEVERE WITH THE OUTSIDE POTENTIAL FOR DAMAGING WINDS AND LARGE HAIL. CHANCES WAY TOO SMALL FOR ANY ONE LOCATION TO ACTUALLY SEE THIS SEVERITY...MUCH LESS GET RAINED ON. AT MOST...WILL INTRO A VCTS/CB GROUP. DEVELOPING GUSTY SW WINDS THIS AFTERNOON WILL SHIFT OUT OF THE NW LATE IN THE TAF PERIOD BEHIND THE COLD FRONT. && .MARINE... ISSUED AT 407 AM EDT MON JUL 22 2013 LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS. THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED. HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK... GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH THURSDAY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...SD SYNOPSIS...SD SHORT TERM...DL LONG TERM...SD AVIATION...SD MARINE...DL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
640 AM CDT MON JUL 22 2013 .UPDATE... FOR 12Z AVIATION DISCUSSION BELOW && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT MON JUL 22 2013 EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE 22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY /MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35. CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT. HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 359 AM CDT MON JUL 22 2013 MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT. THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH SATURDAY. AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF THE BUNCH. FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE. ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH. IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE 22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE ABLE MAKE A RUN AT THAT RECORD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 617 AM CDT MON JUL 22 2013 THERE SHOULD BE AN OVERALL LULL IN CONVECTIVE ACTIVITY FOR THE NEXT SEVERAL HOURS...WITH REDEVELOPMENT EXPECTED BY 16Z AS DIURNAL DESTABILIZATION OCCURS IN CONJUNCTION WITH THE ADVANCING COLD FRONT. SHOWERS AND THUNDERSTORMS SHOULD MOSTLY BE CONFINED TO FAR EAST CENTRAL MN AND WEST CENTRAL WI...WITH KMSP BEING ON THE WESTERN EDGE OF THE REDEVELOPMENT AREA. HAVE INCLUDED VCTS AT KMSP...TEMPOS AT WI SITES /KRNH AND KEAU/...AND DRY ELSEWHERE FOR THIS AFTERNOON. LOW-END VFR TO HIGH-END MVFR CONDITIONS POSSIBLE WITH ANY CONVECTION. SOUTH/SOUTHWEST WINDS AHEAD OF THE FRONT...VEERING TO NORTHWEST AND GUSTING TO BETWEEN 20 AND 25 /KNOTS/ WITH THE FROPA. CLEARING SKIES THIS EVENING...WITH VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. KMSP... COULD SEE A PERIOD OF SCT MVFR CIGS AS STRATUS OVER SERN MN CREEPS NORTH THIS MORNING...BUT EXPECT THAT TO BREAK UP AS DRIER AIR IS ENCOUNTERED. OTHERWISE...THERE/S A LOW CHANCE FOR THUNDERSTORM REDEVELOPMENT DURING THE LATE MORNING AND EARLY AFTERNOON AS THE COLD FRONT PASSES. HOWEVER...COVERAGE IS EXPECTED TO BE SPOTTY WITH HIGHER CHANCES TO THE EAST OF KMSP...SO HAVE ONLY INCLUDED A VCTS AT THIS POINT. SOUTH/SOUTHWEST WINDS THROUGH THE MORNING AHEAD OF THE FRONT...THEN SHIFTING TO THE NORTHWEST AND GUSTING TO AROUND OR JUST OVER 20 KTS THIS AFTERNOON BEHIND THE FRONT. /OUTLOOK FOR KMSP/ TUE...VFR. WINDS N 5 TO 10 KT. WED...VFR. MVFR WITH A CHANCE OF SHRA/TSRA LATE NIGHT. WINDS S 5 KT. THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS WSW 5 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...MPG AVIATION...LS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
911 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 911 AM CDT MON JUL 22 2013 FIRST FORECAST UPDATE OF THE DAY HAS BEEN SENT. IN SHORT...ANOTHER TRICKY DAY/EVENING OF THUNDERSTORM CHANCES AWAITS THE LOCAL AREA. ESSENTIALLY...THE ONLY NOTABLE CHANGE FROM PREVIOUS FORECAST SO FAR WAS TO TRIM CENTRAL/NORTHEAST PORTIONS OF THE CWA FROM ANY THUNDERSTORM MENTION THIS MORNING...WHILE LEAVING MORNING CHANCES INTACT IN KS ZONES...AND MAINLY WEST OF A GOTHENBURG-ALMA LINE IN NEBRASKA TO ACCOUNT FOR THE FAIRLY PERSISTENT NARROW NORTHWEST- SOUTHEAST AXIS OF CONVECTION PRIMARILY AFFECTING FURNAS COUNTY AT THIS TIME. OTHER THAN MAYBE SOME SMALL HAIL...NOT EXPECTING A MORNING SEVERE THREAT. FOR THIS AFTERNOON...ITS HARD TO ARGUE WITH THE SPC SLIGHT RISK FOR ROUGHLY THE SOUTHEAST 2/3 OF THE CWA...ALTHOUGH ITS TOUGH TO SAY WHETHER WE MIGHT ONLY GET 1 OR 2 ISOLATED STRONG-SEVERE STORMS...OR POTENTIALLY MORE SCATTERED COVERAGE. EITHER WAY...THE PRIMARY FORCING MECHANISM ALOFT LOOKS TO BE A FAIRLY SUBTLE SHORTWAVE TROUGH DRIFTING EAST-SOUTHEAST OUT OF WYOMING...WHILE AT THE SURFACE A FAIRLY WEAK COLD FRONT WILL SINK SOUTHWARD INTO PARTS OF THE CWA AS THE DAY WEARS ON...PROVIDING AT LEAST LIMITED LOW-LEVEL CONVERGENCE. THE LATEST RAP FORECAST VALID FOR 21Z/4PM PAINTS 1000-2500 J/KG OF 0-1KM MLCAPE ACROSS MOST OF THE CWA...HIGHEST IN THE SOUTH...IN THE PRESENCE OF DECENT 0-6KM DEEP LAYER SHEAR OF 35-40KT...SO CERTAINLY A THREAT FOR SOME SOUTHEAST-MOVING STRONG TO SEVERE STORMS AND POTENTIALLY SUPERCELLS EXISTS...ALTHOUGH WORKING AGAINST STORM FORMATION APPEARS TO BE AT LEAST A WEAK CAP EVIDENT ON FORECAST SOUNDINGS AROUND 700-650 MILLIBARS...SO ITS ALSO NOT OUT OF THE QUESTION THAT OUR LOCAL AREA COULD LARGELY STEER CLEAR OF AN AFTERNOON/EVENING STORM THREAT...WITH BETTER CHANCES POTENTIALLY FOCUSING JUST TO OUR SOUTH/EAST. EVEN THOUGH THE GREATEST SEVERE THREAT WOULD THEORETICALLY FOCUS ACROSS SOUTHERN PORTIONS OF OUR AREA...HAVE PUT AT LEAST A SLIGHT CHANCE OF STORMS EVEN IN FAR NORTHERN COUNTIES FOR AT LEAST A FEW HOURS THIS AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CDT MON JUL 22 2013 THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR FLOW. THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND 06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY THEN. THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST STORMS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND TEMPERATURES. MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A LITTLE DIFFERENT WITH EACH MODEL. THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE AREA. TEMPERATURES WILL BE COOLER THAN TODAY. A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY. TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME LINGERING THUNDERSTORMS. FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER SIDE DURING THIS TIME. && .AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z TUESDAY MORNING) ISSUED AT 523 AM CDT MON JUL 22 2013 WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS AT KGRI...BUT ANY THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE EAST NORTHEAST. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
625 AM CDT MON JUL 22 2013 .AVIATION... 12Z TAFS FOR KOFK...KLNK AND KOMA. AS HAS BEEN THE CASE FOR THE PAST FEW DAYS...THE MAIN CONCERN AND THE PRIMARY CHALLENGE FOR THE TAFS WILL BE THUNDERSTORM DEVELOPMENT. TODAY A COLD FRONT WILL MOVE THROUGH EASTERN NEBRASKA...SWITCHING THE WINDS FROM MOSTLY SOUTHERLY TO THE NORTHWEST. THE FRONT IS EXPECTED TO REACH KOFK AT 16Z...KOMA AT 21Z...AND KLNK AT 22Z. THE FRONT WILL HELP TO TRIGGER THUNDERSTORM DEVELOPMENT...BUT BETTER CHANCES ARE AT KOMA AND KLNK BECAUSE THE INSTABILITY WILL BE GREATER WHEN THE FRONT COMES THROUGH THOSE LOCATIONS. THEREFORE HAVE INCLUDED TSRA PROB30 GROUPS FOR THOSE TWO TAFS. A FEW STRONG OR EVEN SEVERE STORMS WILL BE POSSIBLE. GENERALLY EXPECT ANY CONVECTION THAT DEVELOPS TODAY TO EVENTUALLY DIMINISH OVERNIGHT AND EXPECT VFR CONDITIONS AFTER ANY THUNDERSTORMS. NIETFELD && .PREV DISCUSSION... /ISSUED 304 AM CDT MON JUL 22 2013/ .DISCUSSION... PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35 KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING. SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED TUESDAY AS WELL. THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A SMALL PRECIP CHANCE SUNDAY INTO MONDAY. DEWALD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
532 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CDT MON JUL 22 2013 THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR FLOW. THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND 06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY THEN. THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST STORMS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND TEMPERATURES. MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A LITTLE DIFFERENT WITH EACH MODEL. THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE AREA. TEMPERATURES WILL BE COOLER THAN TODAY. A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY. TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME LINGERING THUNDERSTORMS. FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER SIDE DURING THIS TIME. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 523 AM CDT MON JUL 22 2013 WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS AT KGRI...BUT ANY THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE EAST NORTHEAST. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM MONDAY... REST OF TODAY: VERY MOIST AIR MASS IN PLACE AS NOTED BY 12Z GSO/MHX SOUNDINGS AND BLENDED TPW IMAGERY... WITH PW RANGING FROM 2.0-2.2 INCHES WEST TO EAST... ALTHOUGH VALUES ARE SLIGHTLY LOWER TO OUR WEST. LATEST SURFACE ANALYSIS SHOWS THE NEARLY STATIONARY SYNOPTIC FRONTAL ZONE FROM IA EAST ACROSS NRN IL/IN/OH TO PA/MA. A WEAK LOW IS EVIDENT OVER SCENTRAL VA WITH TRAILING WEAK TROUGHING THROUGH CENTRAL NC... AND A MORE PROMINENT LOW AND TROUGH OVER SRN IL/SE MO/NW AR. THE LATTER FEATURE IS ASSOCIATED WITH A POTENT MID LEVEL SHORTWAVE TROUGH THAT IS ON PACE TO APPROACH OUR AREA LATE TONIGHT. ANOTHER UPPER LEVEL WAVE NOW OVER THE AL/GA BORDER IS EXPECTED TO TRACK ACROSS FAR SRN AND SE NC THIS EVENING. MODELS ARE NOT IN GREAT AGREEMENT ON THE TIMING AND EXTENT OF CONVECTION THIS AFTERNOON/ EVENING. THE 4KM WRF-ARW/WRF-NMM AND HRRR DEPICT JUST SCATTERED COVERAGE IN THE EARLY AFTERNOON IN THE ERN CWA... WHERE THE CINH HAS VANISHED AND WHERE MLCAPE HAS ALREADY CLIMBED NEAR 1000 J/KG. BUT THE DEEP LAYER SHEAR IS QUITE POOR (UNDER 15 KTS) AND EXPECTED TO REMAIN SO THROUGH THE DAY... NOT SUPPORTIVE OF STRONG ORGANIZED CONVECTION. PW WILL ALSO BE DROPPING A BIT THIS AFTERNOON... AND THE STRONG MISS VALLEY WAVE SHIFTING EASTWARD MAY HELP DEAMPLIFY THE AL/GA WAVE AS IT CROSSES THE CAROLINAS. WILL ADJUST POPS A BIT THROUGH THE AFTERNOON TO FOCUS THE BETTER COVERAGE (30-40%) IN THE EAST... WHERE MOISTURE AND INSTABILITY IS EXPECTED TO BE BETTER BENEATH WEAK UPPER-LEVEL DPVA... WITH LOWER POPS OF 20-30% IN THE WRN CWA. LOCALLY HEAVY RAIN IS STILL POSSIBLE WITH WARM LAYERS (LCL-0C) OF 3.5-3.8 KM... AND ANY ADDITIONAL RAIN IN AREAS THAT SAW A LOT YESTERDAY (SUCH AS THE GREENSBORO AREA) COULD EASILY SEE QUICK FLOODING TODAY. FREQUENT LIGHTNING IS STILL A SECONDARY CONCERN... ALTHOUGH THE MARGINAL -10C TO -30C CAPE PEAKING AT 500 J/KG IS NOT AS HIGH AS IN SOME OF THE PROLIFIC LIGHTNING EVENTS WE`VE HAD RECENTLY. TEMP RISE SO FAR HAS BEEN GREATLY TEMPERED BY STUBBORN STRATOCU OVER MUCH OF CENTRAL NC... WITH ONLY ERN/SRN SECTION SEEING SOME HOLES IN THE CLOUDS. EXPECT THIS WILL START TO MIX OUT SHORTLY (BASED ON PILOT REPORTS THAT THIS DECK IS 500-1000 FT THICK)... BUT WITH THE DELAYED INSOLATION... WILL STILL NEED TO TRIM A FEW DEGREES OFF HIGHS... GOING WITH 85-90. -GIH WHILE BULK OF CONVECTION WILL DIMINISH IN THE EVENING WITH LOSS OF HEATING...APPROACH OF THE MID-UPPER LEVEL TROUGH WILL LIKELY MAINTAIN A FEW SHOWERS/STORMS INTO THE OVERNIGHT HOURS. CONTINUED MUGGY TONIGHT WITH MIN TEMPS NEAR 70-LOWER 70S. -WSS && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 300 AM MONDAY... EXPECT A CONTINUATION OF THE UNSETTLED WEATHER PATTERN TUESDAY DUE TO PRESENCE OF MID-UPPER LEVEL TROUGH OVER THE CAROLINAS THOUGH FOCUS MAY BE MORE IN THE EAST VERSUS WEST. SHORT TERM MODEL GUIDANCE SUGGEST WESTERLY 850MB FLOW DEVELOPING LATE TODAY INTO TUESDAY WITH A 850MB TROUGH CROSSING THE REGION TUESDAY AFTERNOON. RH CROSS SECTION SUGGEST THE AIR MASS DRYING OUT ABOVE 700MB/10K FT DURING THE COURSE OF THE AFTERNOON...ESPECIALLY WEST OF HIGHWAY 1. THE DOWNSLOPE FLOW IN THE WAKE OF THIS SYSTEM AND AN AIR MASS NOT AS MOIST MAY LIMIT/INHIBIT CONVECTIVE DEVELOPMENT IN THE WEST ON TUESDAY. WITH TROUGH CROSSING THE EAST DURING MAX HEATING...STILL EXPECT AT A MINIMUM 50 PERCENT COVERAGE. PRESENCE OF DRIER AIR ALOFT MAY LEAD TO EVAPORATIVE COOLING IN VICINITY OF THUNDERSTORM DOWNDRAFTS...LEADING TO STRONG/LOCALLY DAMAGING WINDS WITH THE STRONGER CELLS. MAJORITY OF THE CONVECTION WILL DISSIPATE SHORTLY AFTER SUNSET THOUGH THE APPROACH OF A SECONDARY TROUGH IN THE FLOW ALOFT MAY TRIGGER ADDITIONAL ACTIVITY LATE TUESDAY NIGHT-EARLY WEDNESDAY MORNING. THE DRIER AIR MASS ALOFT SHOULD ALLOW FOR PERIODS OF PARTIAL SUNSHINE. THIS MAY LEAD TO AFTERNOON TEMPS A COUPLE OF DEGREES WARMER THAN TODAY. EXPECT MAX TEMPS NEAR 90 TO LOWER 90S AREAWIDE. MIN TEMPS NEAR 70-LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... WEDNESDAY THROUGH THURSDAY: THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC STATES. DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN NC. NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE. FRIDAY THROUGH SUNDAY: FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE... WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING. ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65 TO 70. TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO 30 PERCENT. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 730 AM MONDAY... A MOIST AIR MASS WILL REMAIN OVER CENTRAL NC THROUGH MID WEEK. MEANWHILE AN UPPER LEVEL TROUGH WILL DRIFT SLOWLY EAST FROM THE TN VALLEY TODAY TO THE CAROLINAS TUESDAY. THIS UPPER LEVEL FEATURE WILL REMAIN OVER THE REGION THROUGH THURSDAY THEN WEAKEN/DISSIPATE. DISTURBANCES ROTATING THROUGH THIS TROUGH...INTERACTING WITH THE MOIST AIR MASS AND AFTERNOON HEATING...WILL TRIGGER SCATTERED-NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY. CONVECTIVE COVERAGE IS EXPECTED TO BE GREATEST IN THE LATE AFTERNOON THROUGH THE EARLY EVENING HOURS THOUGH ISOLATED SHOWERS MAY OCCUR AT ANY TIME. EXPECT MVFR/IFR CEILINGS AND MVFR VISIBILITIES IN VICINITY OF THE SHOWERS AND STORMS. THIS SCENARIO SHOULD PLAY OUT EACH AFTERNOON THROUGH WEDNESDAY WITH LESS COVERAGE EXPECTED THURSDAY AND FRIDAY. DUE TO THE PRESENCE OF THE MOIST AIR...WIDESPREAD STRATUS AND ASSOCIATED IFR CEILINGS WILL OCCUR EACH MORNING JUST PRIOR TO DAYBREAK...CONTINUING UNTIL 11 AM OR NOON EACH DAY. POCKETS OF IFR VISIBILITY DUE TO FOG MAY ALSO OCCUR. THE FOG SHOULD LIFT BY 9-10 AM EACH DAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD/WSS SHORT TERM...WSS LONG TERM...CBL AVIATION...WSS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1047 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 1038 AM CDT MON JUL 22 2013 MAIN CHALLENGES TODAY ARE CLOUDS AND TEMPERATURES. COOL STRATUS CLOUD DECK LIKELY TO BE MORE PERSISTENT TODAY THAN EARLIER FORECAST. AS A RESULT OF MORE CLOUDS ALSO LOWERED TEMPERATURES ABOUT 2 TO 3 DEGREES ACROSS THE NORTH AND CENTRAL. EXPECT SUNNY OR MOSTLY SUNNY SKIES SOUTHWEST. UPDATE ISSUED AT 655 AM CDT MON JUL 22 2013 MAIN PROBLEM FOR THE MORNING UPDATE WAS CLOUD COVER. EXPANSIVE AREA OF STRATUS ACROSS EASTERN SASKATCHEWAN AND MANITOBA IS SPILLING SOUTHWARD INTO NORTH DAKOTA. MOST MODELS ARE NOT CAPTURING THE LOW LEVEL MOISTURE WELL. THE 10 UTC RAP WAS TOO GENEROUS WITH ITS 925MB RH LAYER BUT DOES SEEM TO HAVE A GOOD TREND ON DIMINISHING IT MID MORNING INTO EARLY AFTERNOON. USED A BLEND OF THE RAP WITH CURRENT OBS AND COORDINATION WITH FGF TO TAKE A SHOT AT CLOUD COVER DURING THE DAY. WITH ONLY A THIN LAYER OF MOISTURE...THINK EVEN THE FAR EASTERN PORTIONS OF THE CWA SHOULD SEE SOME AFTERNOON SUNSHINE. OTHERWISE NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 357 AM CDT MON JUL 22 2013 HIGH BASED THUNDERSTORMS LATE THIS EVENING AND TONIGHT ACROSS WESTERN NORTH DAKOTA CAPABLE OF STRONG WINDS WILL HIGHLIGHT THE SHORT TERM FORECAST. OVERALL...A MUCH QUIETER AND COOLER DAY ACROSS WESTERN AND CENTRAL NORTH DAKOTA IS EXPECTED COMPARED TO SUNDAY. GIVEN GOOD MODEL AGREEMENT OF SURFACE HIGH PRESSURE ACROSS MUCH OF NORTH DAKOTA...AND LEE LOW PRESSURE ACROSS NORTHEAST WYOMING THROUGH CENTRAL MONTANA...UTILIZED A BLEND OF THE 00 UTC GUIDANCE SUITE. WITH WEAK NORTHERLY FLOW AND A MUCH COOLER AIRMASS IN PLACE...HIGHS IN THE UPPER 60S ARE FORECAST ACROSS THE TURTLE MOUNTAINS...TO THE 70S FOR MOST OTHER LOCATIONS ACROSS THE AREA...WITH MID 80S FOR THE FAR SOUTHWEST WHERE LOW LEVEL THERMAL FIELDS AND MIXING ARE EXPECTED TO BE GREATEST. GIVEN THE GOOD PERFORMANCE OF THE 00 UTC 4KM WRF...AND THE REMAINING HIGH RESOLUTION MODELS CONTAINED WITHIN THE 00 UTC SPC STORM SCALE ENSEMBLE OF OPPORTUNITY...WILL FOLLOW CLOSELY TO THESE SOLUTIONS FOR THE CONVECTIVE POTENTIAL THIS EVENING AND TONIGHT ACROSS THE WEST. EXPECT SURFACE BASE CONVECTIVE DEVELOPMENT ALONG THE AFOREMENTIONED LEE TROUGH ACROSS MONTANA THIS AFTERNOON WITH THE APPROACH OF THE SHORTWAVE CURRENTLY ACROSS WASHINGTON STATE. STORMS ARE FORECAST TO PROPAGATE SOUTHEAST INTO WESTERN NORTH DAKOTA BETWEEN 00-03 UTC. THE 00 UTC NAM/GFS BUFR SOUNDINGS DEPICT INVERTED V PROFILES ACROSS THE WEST THIS EVENING. WHILE OVERALL INSTABILITY IS MARGINAL FOR SEVERE CONVECTION...AMPLE DEEP LAYER SHEAR NEAR 40 KTS AND HIGH BASES NEAR 750-700 MB SUGGEST A LOW END THREAT FOR STRONG WINDS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 357 AM CDT MON JUL 22 2013 AN ACTIVE PATTERN WILL CONTINUE THROUGH THE EXTENDED PERIOD. WE BEGIN WITH A NORTHWEST FLOW ALOFT AND TRANSITION TO A SOUTHWEST UPPER FLOW LATE IN THE EXTENDED PERIOD. GENERAL AGREEMENT BETWEEN DETERMINISTIC MODELS IN LARGE SCALE FLOW AND WILL UTILIZE A MODEL BLEND WITH PERSISTENCE. ON TUESDAY...HIGH PRESSURE OVER THE EASTERN DAKOTAS WITH UPPER LEVEL JET ENERGY INDUCING SCATTERED SHOWERS AND THUNDERSTORMS OVER WESTERN NORTH DAKOTA EARLY TUESDAY. THIS SHOULD TRANSLATE INTO SOUTH DAKOTA DURING THE MORNING. MODELS INDICATE ANOTHER IMPULSE MOVING THROUGH SOUTHERN CANADA INDUCING SURFACE LOW PRESSURE OVER EASTERN MONTANA BY TUESDAY AFTERNOON. INCREASING WARM ADVECTION AHEAD OF THE LOW COMBINED WITH THE AFOREMENTIONED IMPULSE WILL PRODUCE STEEPENING LAPSE RATES AND A VEERING WIND PROFILE SUPPORTIVE OF STRONG TO SEVERE STORMS TRANSLATING NORTHWEST TO SOUTHEAST ACROSS THE LOCAL AREA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. PERHAPS SOME LINGERING CONVECTION IN THE FAR EAST WEDNESDAY BUT FOR THE MOST PART WEDNESDAY IS EXPECTED TO BE DRY AS SURFACE HIGH PRESSURE TRACKS ACROSS THE AREA. THURSDAY IS ALSO EXPECTED TO BE RELATIVELY QUIET BUT UPPER LEVEL JET ENERGY REMAINING OVER THE AREA COMBINED WITH DIURNAL HEATING WILL STILL SUPPORT ISOLATED TO SCATTERED THUNDERSTORMS. A MORE SIGNIFICANT WAVE MOVES THROUGH THE AREA THURSDAY NIGHT INTO FRIDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. UPPER LEVEL RIDGING BUILDS OVER THE AREA ON SATURDAY. THE ECMWF IS QUICKER TO BRING THE RIDGE INTO THE AREA RESULTING IN A DRY FORECAST SATURDAY. THE GFS KEEPS AN AREA OF CONVECTION OVER THE WEST AND SOUTH CENTRAL THROUGH MIDDAY BEFORE DRYING THINGS OUT LATER IN THE DAY. THE ECMWF IS ALSO QUICKER TO BREAK DOWN THE RIDGE AND INTRODUCE SOUTHWEST FLOW OVER THE AREA BY SUNDAY AFTERNOON...WHILE THE GFS KEEPS THE LOCAL AREA DRY ON SUNDAY WITH ANY CONVECTION HOLDING OFF UNTIL LATE SUNDAY NIGHT IN THE FAR WEST. ALL IN ALL A RATHER ACTIVE PATTERN WITH SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1038 AM CDT MON JUL 22 2013 AT 10 AM CDT...SURFACE HIGH PRESSURE OVER SASKATCHEWAN AND MANITOBA WAS BUILDING SOUTH INTO THE NORTHERN PLAINS. COOL STRATO-CU LAYER HAS EXTENDED ACROSS ALL BUT THE SOUTHWEST. AM NOW MORE PESSIMISTIC ON THE EVENTUAL BREAKUP OF THE CLOUD DECK BY LATE THIS MORNING. EXTENDED THE CLOUDS THROUGH THE EARLY TO MID AFTERNOON. MVFR CONDITIONS FROM KMOT-KBIS-KJMS THROUGH 20Z...THEN IMPROVING TO VFR. KDIK SHOULD REMAIN VFR...WHILE KISN WILL BE IN THE EDGE...BECOMING VFR A LITTLE EARLIER. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...AYD LONG TERM...TWH AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
656 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 655 AM CDT MON JUL 22 2013 MAIN PROBLEM FOR THE MORNING UPDATE WAS CLOUD COVER. EXPANSIVE AREA OF STRATUS ACROSS EASTERN SASKATCHEWAN AND MANITOBA IS SPILLING SOUTHWARD INTO NORTH DAKOTA. MOST MODELS ARE NOT CAPTURING THE LOW LEVEL MOISTURE WELL. THE 10 UTC RAP WAS TOO GENEROUS WITH ITS 925MB RH LAYER BUT DOES SEEM TO HAVE A GOOD TREND ON DIMINISHING IT MID MORNING INTO EARLY AFTERNOON. USED A BLEND OF THE RAP WITH CURRENT OBS AND COORDINATION WITH FGF TO TAKE A SHOT AT CLOUD COVER DURING THE DAY. WITH ONLY A THIN LAYER OF MOISTURE...THINK EVEN THE FAR EASTERN PORTIONS OF THE CWA SHOULD SEE SOME AFTERNOON SUNSHINE. OTHERWISE NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 357 AM CDT MON JUL 22 2013 HIGH BASED THUNDERSTORMS LATE THIS EVENING AND TONIGHT ACROSS WESTERN NORTH DAKOTA CAPABLE OF STRONG WINDS WILL HIGHLIGHT THE SHORT TERM FORECAST. OVERALL...A MUCH QUIETER AND COOLER DAY ACROSS WESTERN AND CENTRAL NORTH DAKOTA IS EXPECTED COMPARED TO SUNDAY. GIVEN GOOD MODEL AGREEMENT OF SURFACE HIGH PRESSURE ACROSS MUCH OF NORTH DAKOTA...AND LEE LOW PRESSURE ACROSS NORTHEAST WYOMING THROUGH CENTRAL MONTANA...UTILIZED A BLEND OF THE 00 UTC GUIDANCE SUITE. WITH WEAK NORTHERLY FLOW AND A MUCH COOLER AIRMASS IN PLACE...HIGHS IN THE UPPER 60S ARE FORECAST ACROSS THE TURTLE MOUNTAINS...TO THE 70S FOR MOST OTHER LOCATIONS ACROSS THE AREA...WITH MID 80S FOR THE FAR SOUTHWEST WHERE LOW LEVEL THERMAL FIELDS AND MIXING ARE EXPECTED TO BE GREATEST. GIVEN THE GOOD PERFORMANCE OF THE 00 UTC 4KM WRF...AND THE REMAINING HIGH RESOLUTION MODELS CONTAINED WITHIN THE 00 UTC SPC STORM SCALE ENSEMBLE OF OPPORTUNITY...WILL FOLLOW CLOSELY TO THESE SOLUTIONS FOR THE CONVECTIVE POTENTIAL THIS EVENING AND TONIGHT ACROSS THE WEST. EXPECT SURFACE BASE CONVECTIVE DEVELOPMENT ALONG THE AFOREMENTIONED LEE TROUGH ACROSS MONTANA THIS AFTERNOON WITH THE APPROACH OF THE SHORTWAVE CURRENTLY ACROSS WASHINGTON STATE. STORMS ARE FORECAST TO PROPAGATE SOUTHEAST INTO WESTERN NORTH DAKOTA BETWEEN 00-03 UTC. THE 00 UTC NAM/GFS BUFR SOUNDINGS DEPICT INVERTED V PROFILES ACROSS THE WEST THIS EVENING. WHILE OVERALL INSTABILITY IS MARGINAL FOR SEVERE CONVECTION...AMPLE DEEP LAYER SHEAR NEAR 40 KTS AND HIGH BASES NEAR 750-700 MB SUGGEST A LOW END THREAT FOR STRONG WINDS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 357 AM CDT MON JUL 22 2013 AN ACTIVE PATTERN WILL CONTINUE THROUGH THE EXTENDED PERIOD. WE BEGIN WITH A NORTHWEST FLOW ALOFT AND TRANSITION TO A SOUTHWEST UPPER FLOW LATE IN THE EXTENDED PERIOD. GENERAL AGREEMENT BETWEEN DETERMINISTIC MODELS IN LARGE SCALE FLOW AND WILL UTILIZE A MODEL BLEND WITH PERSISTENCE. ON TUESDAY...HIGH PRESSURE OVER THE EASTERN DAKOTAS WITH UPPER LEVEL JET ENERGY INDUCING SCATTERED SHOWERS AND THUNDERSTORMS OVER WESTERN NORTH DAKOTA EARLY TUESDAY. THIS SHOULD TRANSLATE INTO SOUTH DAKOTA DURING THE MORNING. MODELS INDICATE ANOTHER IMPULSE MOVING THROUGH SOUTHERN CANADA INDUCING SURFACE LOW PRESSURE OVER EASTERN MONTANA BY TUESDAY AFTERNOON. INCREASING WARM ADVECTION AHEAD OF THE LOW COMBINED WITH THE AFOREMENTIONED IMPULSE WILL PRODUCE STEEPENING LAPSE RATES AND A VEERING WIND PROFILE SUPPORTIVE OF STRONG TO SEVERE STORMS TRANSLATING NORTHWEST TO SOUTHEAST ACROSS THE LOCAL AREA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. PERHAPS SOME LINGERING CONVECTION IN THE FAR EAST WEDNESDAY BUT FOR THE MOST PART WEDNESDAY IS EXPECTED TO BE DRY AS SURFACE HIGH PRESSURE TRACKS ACROSS THE AREA. THURSDAY IS ALSO EXPECTED TO BE RELATIVELY QUIET BUT UPPER LEVEL JET ENERGY REMAINING OVER THE AREA COMBINED WITH DIURNAL HEATING WILL STILL SUPPORT ISOLATED TO SCATTERED THUNDERSTORMS. A MORE SIGNIFICANT WAVE MOVES THROUGH THE AREA THURSDAY NIGHT INTO FRIDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. UPPER LEVEL RIDGING BUILDS OVER THE AREA ON SATURDAY. THE ECMWF IS QUICKER TO BRING THE RIDGE INTO THE AREA RESULTING IN A DRY FORECAST SATURDAY. THE GFS KEEPS AN AREA OF CONVECTION OVER THE WEST AND SOUTH CENTRAL THROUGH MIDDAY BEFORE DRYING THINGS OUT LATER IN THE DAY. THE ECMWF IS ALSO QUICKER TO BREAK DOWN THE RIDGE AND INTRODUCE SOUTHWEST FLOW OVER THE AREA BY SUNDAY AFTERNOON...WHILE THE GFS KEEPS THE LOCAL AREA DRY ON SUNDAY WITH ANY CONVECTION HOLDING OFF UNTIL LATE SUNDAY NIGHT IN THE FAR WEST. ALL IN ALL A RATHER ACTIVE PATTERN WITH SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 655 AM CDT MON JUL 22 2013 MVFR STRATUS CONTINUES TO SPREAD ACROSS NORTHWEST AND CENTRAL NORTH DAKOTA AND WILL IMPACT KMOT AND KISN THROUGH AT LEAST 15 UTC...BEFORE BEGINNING TO LIFT AND SCATTER. THE STRATUS WILL LIKELY IMPACT KBIS AND KJMS DURING THIS TIMEFRAME AS WELL...HOWEVER...UNCERTAINTY IS HIGHER HERE AS THE STRATUS FIELD SHOULD NOT BE AS WIDESPREAD NEAR THESE TERMINALS. THERE IS A CHANCE OF THUNDERSTORMS ACROSS WESTERN NORTH DAKOTA TONIGHT...HOWEVER...DUE TO UNCERTAINTY IN COVERAGE...WILL LEAVE THE MENTION OUT OF THE KISN AND KDIK TAFS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TWH SHORT TERM...AYD LONG TERM...TWH AVIATION...AYD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1118 AM EDT MON JUL 22 2013 .SYNOPSIS... SFC FRONT STALLING JUST WEST TO EAST ACROSS WEST VIRGINIA NORTHERN PANHANDLE. MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS. && .NEAR TERM /THROUGH TONIGHT/... 1100 AM UPDATE... COMPLICATED FCST SHAPING UP FOR THIS AFTN THRU TONIGHT. WILL BE TRACKING A COUPLE POTENT UPR LVL SYS...THE FIRST OF WHICH CURRENTLY MOVING THRU E OH AND SHOULD BE OUT OF SE OH BY 16Z. THE SECOND LOCATED ACROSS IN AND KY...WITH A MESO VORTEX APPENDAGE MOVING ACROSS S KY. USED LATEST RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SECOND SYS WITH HVY SHRA MOVING BACK INTO NE KY AND SE OH NEXT FEW HRS AND INTO S WV/SW VA BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS TRYING TO SCT OUT E OH OH RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES TDY INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT. UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF AREA AFTER 09Z WITH PCPN THREAT DIMINISHING. PREVIOUS DISCUSSION BELOW... WATER VAPOR IMAGES INDICATE UPPER LOW SPINNING ACROSS SOUTHERN IL...MOVING EAST INTO THE KY AND THE OH VALLEY TODAY. ALTHOUGH THE SFC FRONT IS SUGGESTED TO REMAIN STATIONARY NORTH OF THE AREA...A POSITIVELY TILTED SHORTWAVES AT H5 WILL APPROACH FROM THE WEST AND NORTHWEST TO INTERACT WITH ABUNDANT LOW LEVEL MOISTURE THIS AFTERNOON TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS INTO THE EVENING HOURS. IN FACT...THE NAM SHOWS A H500 SHORTWAVE WITH VORTICITY MAX DOWNSTREAM EAST OF THE TROUGH JUST EAST OF SOUTHEAST OH BY 12Z TODAY. ANOTHER EMBEDDED BUT WEAKER VORT MAX IS EVIDENT UPSTREAM THE TROUGH...WHICH WILL MAKE IT DIG SOUTH INTO WV AND THE APPALACHIANS TONIGHT. THE NAM MODEL SHOW A BUBBLE OF PWATS EXCEEDING 2 INCHES MOVING INTO SOUTHEAST OH BY 15Z TODAY...AND SPREADING NORTHEAST ACROSS SOUTHEAST OH AND PERIOD OF WV THROUGH 00Z TUESDAY. THE NAM...CMC...AND HRRR SUGGEST THAT OUR NORTHWEST QUADRANT WILL RECEIVE THE BEST FORCING DURING THE LATE AFTERNOON...AND ANOTHER PIECE OF ENERGY PASSING ACROSS THE SOUTHERN COALFIELDS AND CENTRAL MOUNTAINS THROUGH TONIGHT. THESE FEATURES COULD ENHANCED CONVECTION DEVELOPMENT OVER THE HIGHER ELEVATIONS...AND ACROSS SOUTHEAST OH AND NORTHERN PORTIONS OF WEST VIRGINIA. THEREFORE...ADJUSTED POPS...HAVING SLIGHT CHANCE POPS IN THE MORNING...AS THE BULK OF PCPN WILL FALL OVER CENTRAL OH. THEN...GRADUALLY INCREASE POPS TO LIKELY THIS AFTERNOON AND CATEGORICAL BY LATE AFTERNOON AND EVENING. USED A BLEND BETWEEN THE BIAS CORRECTED SREF AND GMOS RAW FOR TEMPERATURES THROUGH THE PERIOD. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... EXCEPT FOR THE NAM/SREF SUITE OF MODELS WHICH ARE SLOW OUTLIERS THERE IS GROWING AGREEMENT AMONG THE MODELS OF A FASTER PROGRESSION OF THE COLD FRONT TUESDAY NIGHT...AND OF A QUITE WEAK SECONDARY FRONT WEDNESDAY. FIRST...EXPECT A RAPID DECREASE IN CONVECTION TUESDAY AS AN UPPER DISTURBANCE EXITS AND TAKES MUCH OF THE RICH MOISTURE WITH IT. AGAIN...THE NAM IS A VERY SLOW OUTLIER EXITING THIS SYSTEM AND WAS NOT USED. WILL PAINT HIGH POPS EARLY IN MOUNTAINS BUT DECREASE THAT DURING TUESDAY MORNING. WILL KEEP LOWER POPS TUESDAY AFTERNOON WITH REMAINING LOW LEVEL MOISTURE AND HEATING TO DESTABILIZE THE ATMOSPHERE WELL AHEAD OF THE AFOREMENTIONED COLD FRONT...ESPECIALLY MOUNTAINS WITH AN ELEVATED HEAT SOURCE. WILL RAMP POPS UP AGAIN TUESDAY NIGHT WITH THE FRONT...GOING LIKELY FOR AN ORGANIZED BAND OF CONVECTION ALONG THE FRONT. HOWEVER...LESS RISK OF WATER PROBLEMS WITH THIS FEATURE AS PW`S WILL BE MUCH LESS THAN WE ARE CURRENTLY EXPERIENCING. WILL KEEP LOW POPS IN FOR MAINLY WEDNESDAY AFTERNOON AS THE SECONDARY FRONT DROPS SOUTHEASTWARD ACROSS THE AREA...MOSTLY IN MOUNTAINS. HIGH PRESSURE FINALLY BUILDS IN FOR THURSDAY WITH DRIER AND COOLER AIR BECOMING ESTABLISHED. STILL LINGER JUST A LOW CHANCE POP MOSTLY MOUNTAINS FOR AN AFTERNOON SHOWER PER SQUEEZING OUT ANY LINGERING LOW LEVEL MOISTURE WITH UPSLOPE FLOW AND MODEST COLD ADVECTION ALOFT. LOOK FOR A MODEST COOLING TREND THIS PERIOD...BUT A SIGNIFICANT DRYING OUT. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD. && .LONG TERM /FRIDAY THROUGH SUNDAY/... STILL TRYING TO BRING DRIER AIR THURSDAY INTO FRIDAY. DEEPENING 500 MB TROF OVER EASTERN CANADA MAY PULL ANOTHER DISTURBANCES SE ON SATURDAY. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... IFR/LIFR UNDER DENSE FOG POSSIBLE OVER AREAS THAT RECEIVED RAIN YESTERDAYS AND WHERE SKY CLEARS. EXPECT THIS CONDITIONS MAINLY AT CRW...CKB...NEARBY BKW AND PKB. PLENTY OF CLOUDINESS IS EVIDENT IN IR SATELLITE IMAGES ASSOCIATED WITH CONVECTION OVER NORTH CENTRAL KY...INTO SOUTHERN OH. H7 FLOW SEEMS TO TAKE THESE CLOUDS NORTH NORTHEAST. SOME CLOUDS WILL FILTER INTO SOUTHEAST OH OVERNIGHT WHILE OTHER PATCHES OF CLOUDS DISSIPATE ALLOWING RADIATIONAL COOLING FOR FOG FORMATION. BY 13Z MONDAY...ANY IFR FOG IS EXPECTED TO LIFT INTO MVFR/VFR CONDITIONS THROUGH GREAT PART OF THE MORNING. MODELS INSIST ON ROUNDS OF SHOWERS OR STORMS DEVELOPING EARLY MORNING ACROSS SOUTHEAST OH...TO MOVE NORTHEAST POSSIBLY AFFECTING PKB THROUGH 15Z. THEN...THE NAM/GFS MODELS BRING A STRONG SHORTWAVE BY 18Z MONDAY JUST WEST OF SOUTHEAST OH. THIS FEATURE WILL ENHANCE CONVECTION MONDAY AFTERNOON FOR IFR CONDITIONS ALONG THE STRONGER SHOWERS. SHOWERS AND THUNDERSTORMS ARE LIKELY TO OVERSPREAD THE SOUTHERN TAF SITES BY MONDAY AFTERNOON AND EVENING. THIS WILL BRING WIDESPREAD MVFR CONDITIONS MON WITH IFR CONDITIONS IN THE HEAVIER RAINFALL. SFC FLOW WILL REMAIN CALM OR LIGHT AND VARIABLE. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: HIGH. ALTERNATE SCENARIOS: TIMING/DENSITY OF FOG MAY VARY OVERNIGHT DEPENDING ON CLOUD COVER. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE CONDITIONS MAY VARY EARLY MORNING TO LATE AFTERNOON MONDAY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H L L L L L L M M M HTS CONSISTENCY M M M L M L L L M M M M BKW CONSISTENCY H H H H M L L L L M M M EKN CONSISTENCY H M H H H H M M M M M M PKB CONSISTENCY M H H H H M M M M M M M CKB CONSISTENCY H H H H H H H M M M M M AFTER 12Z TUESDAY... WIDESPREAD IFR TO LIFR POST-RAIN FOG AND/OR LOW CEILINGS OVERNIGHT MON NT INTO TUE MORNING. IFR ALSO POSSIBLE IN VALLEY FOG OR LOW CEILINGS EACH MORNING WED THROUGH THROUGH FRI. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...ARJ/JMV/MZ NEAR TERM...ARJ/30 SHORT TERM...JMV LONG TERM...KTB AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1022 AM CDT MON JUL 22 2013 .DISCUSSION... HAVE UPDATED ZONES AND GRIDS TO REDUCE POPS OVER THE NORTHWEST. RAIN IS BEGINNING TO TAPER OFF OVER THE NORTHWEST AND EXPECT THIS TREND WILL CONTINUE. BOYD && .PREV DISCUSSION... /ISSUED 922 AM CDT MON JUL 22 2013/ MESOSCALE UPDATE... ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON. BOYD PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/ UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S. AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING. PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/ DISCUSSION... THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST 15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT PERIOD OF TIME. THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD. WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS. WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS. UNGER AVIATION...06Z TAF DISCUSSION. UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD HANG ON. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 87 72 91 72 / 90 30 50 30 CLARKSVILLE 86 70 91 70 / 40 30 50 30 CROSSVILLE 80 68 84 68 / 90 40 40 30 COLUMBIA 87 72 90 72 / 90 30 50 40 LAWRENCEBURG 87 71 89 71 / 90 40 50 40 WAVERLY 87 71 92 71 / 50 30 50 30 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
922 AM CDT MON JUL 22 2013 .MESOSCALE UPDATE... ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON. BOYD && .PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/ UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S. AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING. PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/ DISCUSSION... THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST 15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT PERIOD OF TIME. THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD. WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS. WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS. UNGER AVIATION...06Z TAF DISCUSSION. UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD HANG ON. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
520 AM CDT MON JUL 22 2013 .UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S. && .AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING. && .PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/ DISCUSSION... THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST 15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT PERIOD OF TIME. THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD. WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS. WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS. UNGER AVIATION...06Z TAF DISCUSSION. UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD HANG ON. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ROSE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
623 AM CDT MON JUL 22 2013 .MESOSCALE DISCUSSION... ISSUED AT 623 AM CDT MON JUL 22 2013 19.05Z THROUGH 19.09Z HRRR MODEL FORECASTS ARE STAYING EXTREMELY CONSISTENT WITH DEVELOPMENT OF CONVECTION ALONG THE APPROACHING COLD FRONT THIS AFTERNOON. CONVECTION FIRES IN SOUTHEAST MN AND NORTHWEST WI BETWEEN 18-20Z...THEN MARCHES SOUTHEAST THROUGH THE FORECAST AREA...LIKELY EXITING BY 00Z. AN INTERESTING SIGNAL SHOWING UP IS A SPLIT IN THE CONVECTION AREAS ALONG THE FRONT. ONE AREA TRACKS MORE ACROSS CENTRAL/NORTHERN WI...CLOSER TO THE DYNAMICS ASSOCIATED WITH THE SHORTWAVE TROUGH CROSSING LAKE SUPERIOR AND NORTHERN ONTARIO. THE OTHER AREA DROPS DOWN THROUGH EASTERN IOWA...FOLLOWING THE HIGHER INSTABILITY. THIS SIGNAL SHOWS UP TOO IN THE 22.06Z NAM...OUR LOCAL WRF RUN...THE 22.00Z HIRES ARW AND NSSL WRF. WE WILL SEE IF THIS HAPPENS IN REALITY. SPECIFIC STORM SCALE DATA FROM THE HRRR DOES INDICATE POTENTIAL FOR SOME DISCRETE STORM CELLS UPON INITIATION...EVENTUALLY TURNING INTO LINEAR STRUCTURES. THUS...INITIAL STORMS COULD POSE BOTH A LARGE HAIL AND DAMAGING WIND CONCERN...FOLLOWED BY DAMAGING WINDS THEREAFTER. GOING HAZARD CONCERNS IN THE HWO AND OTHER SERVICES REMAIN ON TRACK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING. LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON. THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500 TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS. CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800 MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON. ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE DAMAGING WINDS. THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE 19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS. OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 AM CDT MON JUL 22 2013 SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES. NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND 80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY. PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90 DURING THE DAY ON SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 623 AM CDT MON JUL 22 2013 SOUTHERLY FLOW AHEAD OF A COLD FRONT IN WESTERN MINNESOTA HAS BEEN BRINGING UP MORE MOISTURE INTO THE REGION AND TAF SITES. THIS MOISTURE HAS MANIFESTED ITSELF AS LIFR TO IFR STRATUS...WITH EVEN SOME FOG RANGING FROM VLIFR TO IFR AT RST. CEILINGS AND VISIBILITIES WILL GRADUALLY RISE THROUGH MORNING DUE TO DAYTIME MIXING...WITH BOTH TAF SITES LIKELY VFR BY 16Z. DURING THE AFTERNOON...THE COLD FRONT IS EXPECTED TO MOVE THROUGH THE TAF SITES. THUNDERSTORMS LOOK LIKELY TO ACCOMPANY THE FRONT...SO IT IS JUST A MATTER OF TIMING. BASED ON A CONSENSUS OF HIGH RESOLUTION MODEL FORECASTS...SPED UP THE TIMING FROM THE 06Z TAFS...IMPACTING RST BETWEEN 19-22Z AND LSE BETWEEN 20-23Z. ITS POSSIBLE THE STORMS COULD EXIT THE TAF SITES A LITTLE SOONER. VISIBILITIES AND CEILING MAY FALL TO MVFR OR PERHAPS EVEN LOWER BRIEFLY. ADDITIONALLY...POTENTIAL EXISTS FOR THE STORMS TO BRING STRONG TO DAMAGING WIND GUSTS AND LARGE HAIL. CONFIDENCE IS TOO LOW TO MENTION ANY SEVERE POTENTIAL DIRECTLY IN THE TAFS AT THIS TIME. VFR CONDITIONS WITH WINDS SHIFTING TO THE NORTHWEST ARE EXPECTED BEHIND THE FRONT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ MESOSCALE...AJ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
215 PM EDT MON JUL 22 2013 .UPDATE... ISSUED AT 200 PM EDT MON JUL 22 2013 UPDATED THE FORECAST TO BETTER TIME THE RAIN BAND THROUGH THE CWA AND ALLOW FOR MORE CONVECTION TO DEVELOP IN ITS WAKE. ALSO...TWEAKED THE TEMP AND DEWPOINT TRACES PER THE LATEST OBS AND TRENDS...AS WELL AS TOUCHED UP FORECAST HIGHS. UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH A FRESHENED ZFP. UPDATE ISSUED AT 1025 AM EDT MON JUL 22 2013 13Z SFC ANALYSIS SHOWS A DEVELOPING AREA OF LOW PRESSURE MOVING INTO THE OHIO VALLEY. THIS DEVELOPMENT IS OCCURRING DUE TO AN INBOUND AND SHARPENING 500 MB SHORT WAVE THAT WILL CROSS NORTHERN KENTUCKY LATER TODAY. AS SUCH...IT IS ALSO BRINGING WITH IT A LARGE CLUSTER OF MAINLY MODERATE SHOWERS ALONG WITH A COUPLE OF EMBEDDED THUNDERSTORMS. THE RAIN AREA IS POISED TO ENTER OUR CWA AND PROGRESS FROM WEST TO EAST THROUGH THE REST OF THE MORNING. THE LATEST HRRR DOES SHOW THIS AREA BREAKING UP TOWARD NOON AND MORE SCATTERED CONVECTION DEVELOPING THROUGHOUT EAST KENTUCKY... THEREAFTER. EXPECT THIS SECONDARY CONVECTION...TAPPING INTO HIGH PW AIR IN PLACE...TO HAVE THE BEST CHANCE OF PRODUCING EXCESSIVE RAINS...TRAINING...AND THE POTENTIAL FOR LOCALIZED FLASH FLOODING. HAVE UPDATED THE GRIDS TO REFLECT THIS TYPE OF EVOLUTION TO THE POPS...WX...AND QPF. ALSO...BUMPED UP TEMPS IN THE EAST A NOTCH DUE TO A DECENT SUNNY PATCH MOVING THROUGH ATTM AHEAD OF THE INBOUND MASS OF SHOWERS. MEANWHILE...TOOK DOWN THE MAX TEMPS IN THE WEST A TAD FOR THE OPPOSITE REASON. OTHERWISE...THE THREAT FOR DOWNPOURS LOOKS GOOD FOR MOST OF THE REGION SO WILL CONTINUE THE FFA AND MENTION OF LOCALLY HEAVY RAIN IN THE ZONES/HWO THROUGH THE EVENING. FOR TONIGHT...WILL HAVE TO LOOK CLOSELY AT THE POTENTIAL FOR DENSE FOG IF WE MANAGE TO GET MUCH CLEARING AFTER THE RAINS OF TODAY. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 753 AM EDT MON JUL 22 2013 UPSTREAM RADARS SHOW A LARGE CLUSTER OF SHOWERS AND STORMS MAKING A BEELINE TOWARD EAST KENTUCKY. AS A RESULT...WE NUDGED POPS UP INTO THE CATEGORICAL RANGE FOR ALL BUT OUR EASTERNMOST COUNTIES AS RECENT HRRR RUNS SHOW THE SHOWERS BREAKING UP SOME AS THEY HEAD EAST OF JKL. UPDATE ISSUED AT 655 AM EDT MON JUL 22 2013 MODIFIED THE FORECAST GRIDS TO REFLECT SLOWER ONSET OF PRECIPITATION EARLY THIS MORNING. ALSO ISSUED AN UPDATE TO THE FLASH FLOOD WATCH. THE NEW ZONES WILL BE ISSUED SHORTLY. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 310 AM EDT MON JUL 22 2013 MODELS IN PRETTY GOOD AGREEMENT ON THE OVERALL WEATHER PATTERN FOR THE NEXT COUPLE OF DAY. CONSENSUS VIEW IS FOR WIDESPREAD SHOWERS AND STORMS TO DEVELOP EARLY THIS MORNING AND PERSIST THROUGH THE END OF THE DAY ON TUESDAY. THE PRIMARY CONCERN WILL BE LOCALLY HEAVY RAINFALL AND FLOODING. WITH A DEEP LAYER OF MOISTURE IN THE ATMOSPHERE AND WEAK MIDDLE AND UPPER LEVEL WINDS...ANY STORMS THAT FORM WILL BE SLOW MOVING AND WILL HAVE THE POTENTIAL PRODUCE HEAVY RAINFALL OVER VERY LOCALIZED AREAS...WHICH COULD LEAD TO FLASH FLOODING. HIGH TEMPERATURES TODAY AND TOMORROW WILL BE SLIGHTLY BELOW NORMAL...DUE TO THE INFLUENCE OF WIDESPREAD CLOUD COVER AND SHOWER AND STORM ACTIVITY. A FLASH FLOOD WATCH REMAINS IN EFFECT FOR ALL OF EASTERN KENTUCKY THROUGH MONDAY EVENING. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON JUL 22 2013 LONGWAVE TROUGH NOW BECOMING ESTABLISHED OVER THE EASTERN U.S. WILL REMAIN IN PLACE THROUGH THE LONG TERM PERIOD. AT THE SURFACE...A COLD FRONT WILL SLIP TO OUR SOUTH TUESDAY NIGHT AND WEDNESDAY WITH HIGH PRESSURE BUILDING IN BEHIND. WHILE THE DEEPER MOISTURE WILL BE TO OUR SOUTH BY TUESDAY NIGHT...THE FRONT WILL LIKELY KICK OFF ISOLATED TO SCATTERED SHOWERS/STORMS AS IT PASSES. THE HIGH PRESSURE SYSTEM WILL THEN USHER IN A MUCH DRIER AIR MASS FOR THURSDAY AND FRIDAY. IN FACT...IT APPEARS DEWPOINTS MAY EVEN TUMBLE AS LOW AS THE UPPER 50S BY THURSDAY AFTERNOON...WHICH WILL FEEL VERY NICE AFTER THE RECENT PROLONGED BOUT OF 70 DEGREE DEWPOINTS. FORECASTER CONFIDENCE THEN FALLS AS WE HEAD INTO THE WEEKEND. THE UPPER LEVEL TROUGH WILL DIG BACK IN AFTER A BRIEF RELAXATION FORCING A SURFACE FRONT SOUTHWARD INTO THE OHIO VALLEY. THE 22/00Z ECMWF WANTS TO HOLD A PIECE OF THE UPPER TROUGH BACK OVER THE PLAINS... WHILE THE 22/00Z GFS/GEM/UKMET DO NOT. THIS RESULTS IN A WETTER SOLUTION IN THE GFS/GEM/UKMET MODELS WHILE THE ECMWF IS SLOWER TO BRING IN ANY PRECIP. AS SUCH...WILL TREND BACK A LITTLE WITH POPS TO REFLECT THE ADDED UNCERTAINTY BUT STILL OFFER SCATTERED SHOWERS AND STORMS THROUGHOUT THE WEEKEND. DAYTIME HIGHS WILL CHANGE LITTLE THROUGH THE PERIOD...REACHING THE LOW TO MID 80S EACH DAY. OVERNIGHT LOWS WILL RESPOND TO THE FALLING DEWPOINTS LATE IN THE WEEK...FALLING FROM THE MID TO UPPER 60S TUESDAY NIGHT BACK INTO THE UPPER 50S TO LOW 60S THURSDAY NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 215 PM EDT MON JUL 22 2013 A BAND OF MODERATE TO HEAVY SHOWERS WILL LIFT NORTHEAST THROUGH THE REST OF THE CWA OVER THE NEXT COUPLE OF HOURS. WITH THIS...THE LOWEST VIS AND CIGS WILL OCCUR...DOWN TO LIFR FOR A TIME. OTHERWISE...MORE SCATTERED CONVECTION WILL OCCUR THROUGH THE EVENING SO HAVE CONTINUED A VCTS PERIOD THROUGH 04Z FOR MOST SITES. DO EXPECT SOME CLEARING LATER TONIGHT AND THIS SHOULD BE ENOUGH TO ACTIVATE A FOGGY REGIME. ACCORDINGLY...HAVE TAKEN THE VIS DOWN TO LIFR AT SME AND LOZ TOWARD DAWN TUESDAY AND MVFR AT JKL FOR A TIME. MORE STORMS WILL BE POSSIBLE ON TUESDAY...BUT DO NOT EXPECT THEM TO BECOME PREVALENT UNTIL LATER IN THE AFTERNOON SO HAVE KEPT THEIR MENTION OUT OF THE FORECAST THROUGH 18Z TUESDAY. BREEZY SOUTHWEST WINDS WILL SETTLE DOWN THIS EVENING AND STAY RATHER LIGHT AND VARIABLE INTO TUESDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...ABE AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS CARIBOU ME
648 PM EDT MON JUL 22 2013 .SYNOPSIS... A WARM FRONT WILL APPROACH FROM THE SOUTH TONIGHT. THE FRONT WILL LIFT ONTO THE COAST TUESDAY WHILE A WEAK WAVE OF LOW PRESSURE MOVES ALONG THE FRONT. A COLD FRONT WILL APPROACH TUESDAY NIGHT THEN CROSS THE REGION WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY/... 640 PM UPDATE: MADE SOME MODIFICATIONS TO THE PRECIP CHANCES TO CUT THEM BACK TO SWRN ME USING THE LATEST RUC AND GEM. VISIBLE SATL IMAGERY SHOWED SOME CLOUDS MOVING INTO WESTERN AND DOWNEAST AREAS BUT BREAKING UP AS THEY HIT THE UPPER RIDGE HOLDING IN PLACE. THIS RIDGE IS FCST TO BREAK DOWN AND SHIFT TO THE E OVERNIGHT ALLOWING FOR DEEPER MOISTURE TO STREAM N INTO THE REGION FROM NYS AND PA. TEMPERATURES WERE MODIFIED TO MATCH UP W/THE LATEST TRENDS OF LOW TO MID 70S. TEMPERATURES WILL DROP OFF INTO THE UPPER 60S AND LOWER 70S BY 9 PM. PREVIOUS DISCUSSION... HIGH PRESSURE WILL MOVE AWAY TO THE EAST TONIGHT AS CLOUDS INCREASE AHEAD OF AN APPROACHING WARM FRONT. AS THE WARM FRONT LIFTS NORTH INTO THE GULF OF MAINE TUESDAY MORNING A WEAK WAVE OF LOW PRESSURE TRACKING ALONG THE FRONT WILL CARRY AN AREA OF RAIN INTO THE DOWNEAST REGION. THE LAST FEW RUNS OF THE GFS INDICATE THAT THE RAIN WILL LIFT NORTH TUESDAY MORNING MOVING ACROSS CENTRAL AND EASTERN MAINE AND REACHING NORTHEAST MAINE BY MIDDAY. THE NAM CONFINES SIGNIFICANT RAIN TO DOWNEAST AND EAST CENTRAL AREAS. FOR NOW WILL FORECAST DEFINITE RAIN DOWNEAST AND LIKELY OVER THE NORTH WITH JUST CHANCE IN THE FAR NORTH. THE WARM FRONT STALLS JUST INLAND FROM THE COAST AS THE INITIAL WAVE SLIDES NORTHEAST THROUGH NEW BRUNSWICK LATE TUESDAY. SOME SHOWERS MAY CONTINUE...MAINLY IN DOWNEAST AREAS...AS A SMALL SECONDARY SHORTWAVE MOVING ALONG THE FRONTAL BOUNDARY TRACKS INTO CENTRAL NEW ENGLAND. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... A DISTURBANCE WILL MOVE ALONG A FRONT ALONG THE DOWNEAST COAST TUESDAY NIGHT...WITH A COLD FRONT APPROACHING NORTHWEST MAINE LATE. AN AREA OF RAIN WILL MOVE ACROSS THE REGION WITH THE DISTURBANCE TUESDAY NIGHT. THIS AREA OF RAIN WILL MOVE EAST OVERNIGHT...WITH PRECIPITATION TAPERING TO SHOWERS LATE. SHOWER CHANCES WILL THEN BEGIN TO INCREASE ACROSS NORTHWESTERN AREAS LATER TUESDAY NIGHT IN ADVANCE OF THE APPROACHING COLD FRONT. SHOWERS AND THUNDERSTORMS WILL CROSS THE REGION IN ADVANCE OF THE COLD FRONT WEDNESDAY...THEN END IN THE WAKE OF THE COLD FRONT THROUGH THE AFTERNOON. HIGH PRESSURE WILL BUILD EAST WEDNESDAY NIGHT THEN CROSS THE REGION THURSDAY THROUGH THURSDAY NIGHT WITH PARTLY CLOUDY/MOSTLY CLEAR SKIES. TEMPERATURES WILL BE AT NEAR NORMAL...TO SLIGHTLY BELOW NORMAL...LEVELS WEDNESDAY THROUGH THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... THE EXTENDED MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD. A WEAK HIGH PRESSURE RIDGE WILL BE BUILT OVER THE AREA AT THE START OF THE PERIOD. THERE WILL BE A LOW PRESSURE SYSTEM ALONG THE COAST OF VA...A SECOND LOW PRESSURE SYSTEM OVER LAKE SUPERIOR. FRI EVNG THE LOW ALONG THE COAST OF VA WILL MOVE NORTH. THE GFS AND ECMWF DIFFER ON THE SOLUTION. THE ECMWF BRINGS THE LOW NORTH ALONG THE COAST CENTERED AROUND LONG ISLAND..WITH A WARM FRONT EXTENDING NE INTO THE GULF OF MAINE. THE GFS MOVES THE LOW NORTH BUT KEEPS IT WELL EAST OF THE COAST...AND MAINTAINS THE HIGH PRESSURE RIDGE ACROSS THE AREA. THESE DIFFERENCE CONTINUE INTO SAT MRNG. THE ECMWF MOVES THE LOW NORTH TO BAR HARBOR...EXTENDS THE WARM FRONT EAST INTO NEW BRUNSWICK. THE GFS CONTINUES TO MAINTAIN THE HIGH PRESSURE RIDGE. BOTH MODELS DEEPEN THE LOW OVER LAKE SUPERIOR AND MOVE IT NORTH TO JAMES BAY. BOTH MODELS ALSO SHOW SEVERAL SECONDARY LOWS ALONG A BOUNDARY EXTENDING THROUGH THE GREAT LAKES...THROUGH THE CENTRAL US...TO TEXAS. BY SUN MRNG BOTH MODELS MOVE THE RIDGE EAST OF THE AREA...AS THE FRONT PUSHES INTO VT/NH. BY SUN EVNG THE GFS MOVES THE FRONT INTO WRN MAINE...THE ECMWF INTO NH. MON MRNG THE GFS TO ERN ME...ECMWF WRN ME. MON EVNG THE GFS MOVES THE FRONT THROUGH...THE ECMWF TO ERN ME. BY THE END OF THE PERIOD THE GFS INDICATES THAT MAINE WILL BE INFLUENCED BY WRAP AROUND PRECIP...THE ECMWF MAINTAINS THE LOW OVER MAINE. LOADED MODEL BLEND FOR MAX/MIN TEMP...WND/SKY/POP. ADDED 15 PERCENT TO WINDS FOR GUSTS OVER LAND...20 PERCENT OVER COASTAL WATERS. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... NEAR TERM: VFR CONDITIONS THIS EVENING ARE EXPECTED TO LOWER TO IFR DOWNEAST LATE TONIGHT AND IFR TO MVFR ACROSS THE NORTH TUESDAY MORNING. IFR CONDITIONS IN LOW CLOUDS ARE EXPECTED ON TUESDAY. SHORT TERM: MVFR/IFR...WITH OCCASIONAL LIFR...CONDITIONS ARE EXPECTED ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY. CONDITIONS WILL BEGIN TO IMPROVE LATER WEDNESDAY IN THE WAKE OF THE COLD FRONT. GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS THE REGION WEDNESDAY NIGHT THROUGH SATURDAY. && .MARINE... NEAR TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA THROUGH TUESDAY. HUMID AIR LIFTING NORTH WITH THE WARM FRONT WILL LIKELY RESULT IN SOME FOG OVER THE WATERS LATE TONIGHT INTO TUESDAY. SHORT TERM: SMALL CRAFT ADVISORY LEVEL SEAS ARE POSSIBLE WEDNESDAY INTO WEDNESDAY NIGHT. OTHERWISE...WINDS/SEAS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS TUESDAY NIGHT THROUGH THURSDAY NIGHT. VISIBILITIES WILL BE REDUCED IN RAIN AND FOG TUESDAY NIGHT AND WEDNESDAY...WITH A CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...BLOOMER/HEWITT SHORT TERM...NORCROSS LONG TERM...NORTON AVIATION...BLOOMER/HEWITT/NORCROSS MARINE...BLOOMER/HEWITT/NORCROSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
142 PM EDT MON JUL 22 2013 .SYNOPSIS... ISSUED AT 407 AM EDT MON JUL 22 2013 HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO NORTHERN MICHIGAN. && .UPDATE... ISSUED AT 1200 PM EDT MON JUL 22 2013 MID MORNING SURFACE ANALYSIS SHOWS 999MB LOW CENTER OVER NORTHWEST ONTARIO JUST NORTH OF THE BOUNDARY WATERS...TRAILING COLD FRONT EXTENDS BACK INTO SOUTHWEST MINNESOTA/EASTERN NEBRASKA WITH A WARM FRONT EXTENDING SOUTHEAST ACROSS CENTRAL UPPER/NORTHWEST LOWER MICHIGAN. MOISTURE HAS BEEN INCREASING ACROSS MICHIGAN OVER THE LAST 24 HOURS...PRECIPITABLE WATER ON 12Z APX SOUNDING HAS DOUBLED SINCE 12Z SUNDAY (1.07 INCHES). STRAIGHT MODIFICATION OF THE SOUNDING MIXING TO 800MB (78/58) ONLY YIELDS AROUND 400J/KG MLCAPE BUT DEW POINTS HAVE BEEN CLIMBING INTO THE LOWER 60S...AND TEMPERATURES ALREADY IN THE MID/UPPER 70S. SO AN 81/63 PARCEL PUSHES MLCAPE VALUES ABOVE 1100J/KG. ALREADY GETTING SOME CU DEVELOPING EAST OF AN LDM-PZQ LINE...AND A FEW RADAR RETURNS POPPING UP ALONG THE THUMB. BASIC FORECAST IDEAS WILL REMAIN INTACT WITH CONVECTION POPPING UP THIS AFTERNOON...WITH 1000-1500J/KG MLCAPE EXPECTED. WILL KEEP NORTHWEST LOWER SHORELINE COUNTIES DRY WITH AN ONSHORE BREEZE/LAKE SHADOW. DEEP LAYER SHEAR NOT STRONG TODAY...SOME DECENT VEERING OF WINDS ALOFT BUT NOT MUCH SPEED SHEAR (0-6KM BULK SHEAR VALUES 20-30KTS). HAVE BEEN ADJUSTING THE TIMING A BIT GIVEN CURRENT TRENDS. FORECAST HIGHS UPPER 70S-MID 80S LOOK FINE. UPDATE ISSUED AT 638 AM EDT MON JUL 22 2013 ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END CHANCE FOR A SEVERE STORM OR TWO. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 407 AM EDT MON JUL 22 2013 INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT. OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF 07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE OF LAKE MICHIGAN. CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN. THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z. INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY AREAS. THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z. BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD 1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE BOUNDARY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON JUL 22 2013 THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF THE NEXT WORK WEEK. TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD. TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW WISCONSIN. THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE. TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT. REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND LOWER 70S FOR THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 140 PM EDT MON JUL 22 2013 COUPLE PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE AHEAD OF A COLD FRONT TO CROSS NORTHERN MICHIGAN OVERNIGHT. WINDS SHIFT TO THE NORTHWEST BEHIND THE FRONT AND PERHAPS A PERIOD OF HIGH END IFR CEILINGS EARLY TUESDAY MORNING. && .MARINE... ISSUED AT 407 AM EDT MON JUL 22 2013 LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS. THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED. HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK... GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH THURSDAY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JPB SYNOPSIS...SD SHORT TERM...DL LONG TERM...SD MARINE...DL
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
134 PM EDT MON JUL 22 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 330 AM EDT MON JUL 22 2013 A WARM FRONT WILL BRING A FEW SHOWERS AND THUNDERSTORMS LATER TODAY AND THEN A COLD FRONT WILL BRING MORE SCATTERED SHOWERS AND STORMS TONIGHT INTO TUESDAY. FAIR AND COOLER WEATHER WILL ARRIVE BY LATE TUESDAY AND LAST THROUGH THURSDAY. TEMPERATURES WILL AVERAGE NEAR NORMAL LATE IN THE WEEK THROUGH NEXT WEEKEND. && .UPDATE... ISSUED AT 1110 AM EDT MON JUL 22 2013 DROPPED MAXIMUM TEMPERATURES TODAY SLIGHTLY MAINLY SOUTH OF I-96 TO ACCOUNT FOR THE COOLING EFFECTS OF EXTENSIVE PRECIPITATION OVERNIGHT AND RESIDUAL CLOUD COVER. ALSO RAISED PRECIPITATION CHANCES EAST OF US-131 BASED ON HRRR MODEL GUIDANCE AND TO BETTER AGREE WITH SURROUNDING OFFICES. MAIN FORECAST CONCERN THIS AFTERNOON WILL BE PRECIPITATION CHANCES OVERNIGHT WITH THE APPROACHING COLD FRONT. UPDATE ISSUED AT 537 AM EDT MON JUL 22 2013 A COUPLE OF SHOWERS DEVELOPED IN THE PAST HR...ESPECIALLY NEAR LWA. WENT AND ADDED A RISK FOR A FEW EARLY MORNING SHOWERS PRIMARILY SOUTH OF A BIV TO LAN LINE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON) ISSUED AT 330 AM EDT MON JUL 22 2013 AFTER SOME LINGERING EARLY MORNING SHOWERS OVER OUR SE FCST AREA DRY WX IS ANTICIPATED FOR THE REST OF THE MORNING IN THE WAKE OF THE DEPARTING MCV THAT BROUGHT THE ROUND OF RAIN AND STORMS YESTERDAY EVENING AND OVERNIGHT. SOME WAA SHOWERS AND A FEW STORMS WILL DEVELOP THIS AFTERNOON. A FAIR AMOUNT OF SUN AND SSW WINDS WILL HELP TO BOOST MAX TEMPS INTO THE LOWER TO MIDDLE 80S ACROSS MOST OF OUR AREA TODAY. THE COLD FRONT WILL MOVE IN FROM THE NW TONIGHT AND BRING SCATTERED SHOWERS AND STORMS WHICH WILL LAST THROUGH ABOUT MIDDAY TUESDAY BEFORE THE FRONT CLEARS OUR AREA. A COOLER AND DRIER AIR MASS WILL ADVECT IN BEHIND THAT FRONT AND MAX TEMPS WEDNESDAY WILL ONLY REACH THE 70S. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM EDT MON JUL 22 2013 PATTERN IS LOOKING COOLER WITH TIME ESPECIALLY THIS WEEKEND. MODELS IN DECENT AGREEMENT IN SHOWING A COLD FRONT PUSHING THROUGH FRI NIGHT INTO SAT WITH A WAVE OF LOW PRESSURE FORMING ON IT OVER SOUTHERN LOWER MI. THIS SHOULD LEAD TO SHOWERS AND WITH INSTABILITY AROUND THUNDERSTORMS. IF THE NEW HIGH RES EURO IS CORRECT SAT COULD BE A RATHER WET DAY FOR THE AREA. NORTHERLY FLOW SETS UP BEHIND THE WAVE LEADING TO STRONG COLD AIR ADVECTION. 925 MB TEMPS FALL TO UNDER 10 DEG C 12Z SUN. IF THIS HAPPENS AND THE UPPER LOW DEVELOPS NORTH OF SUPERIOR AS SHOWN BY THE HIGH RES EURO ON SUN...LAKE ENHANCED MOISTURE MAY IMPACT THE FORECAST. I LOWERED TEMPERATURES OVER GUIDANCE FOR SAT NIGHT THROUGH SUN BASED ON THIS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 134 PM EDT MON JUL 22 2013 THERE ARE A COUPLE OF PERIODS OF NOTE IN THE 18Z FCST PACKAGE. FIRST OF ALL...WE ARE SEEING FAIRLY GOOD CUMULUS DEVELOPMENT EARLY THIS AFTERNOON WITH PLENTY OF INSTABILITY PRESENT. THIS HAS INITIALLY DEVELOPED AS MVFR...BUT SHOULD LIFT TO VFR FAIRLY QUICK. SOME CONVERGENCE PRESENT THIS AFTERNOON COULD HELP POP A FEW SHOWERS AND/OR STORMS THROUGH EARLY EVENING. THE CHCS OF THESE HITTING A TERMINAL ARE NOT VERY HIGH...SO WE HAVE USED A VCSH TO COVER THIS FOR NOW. SOME BRIEFLY LOWER CONDITIONS TO MVFR WILL BE POSSIBLE UNDER ANY SHOWER/STORM. ANOTHER THREAT OF SHOWERS AND/OR STORMS WILL BE POSSIBLE AFTER ABOUT 06Z AT KMKG AND THEN SPREAD TO THE SE OVERNIGHT AHEAD OF A COLD FRONT. WE ARE NOT ENTIRELY SURE EVERYONE WILL SEE RAIN FROM THIS AS PCPN LOOKS TO BE DIMINISHING WITH THE FRONT DUE TO THE LOSS OF DIURNAL INSTABILITY. THIS WARRANTS A VCSH ALSO...AND WE CAN FINE TUNE THIS AS TRENDS REVEAL THEMSELVES BETTER. WINDS WILL SHIFT TO THE NW AFTER THE FRONT PASSES TUE MORNING. A MVFR CLOUD DECK SHOULD MOVE IN BEHIND THE FRONT FOR A FEW HOURS TUE MORNING BEFORE IT LIFTS TUE AFTERNOON. && .MARINE... ISSUED AT 1110 AM EDT MON JUL 22 2013 LATEST OMR SHOWS WAVE HEIGHTS GENERALLY BELOW 2 FEET...ALTHOUGH 3 FEET WAS REPORTED AT GRAND HAVEN. AS NOTED IN THE PREVIOUS DISCUSSION...WINDS AND WAVES WILL INCREASE TODAY. ALTHOUGH A SMALL CRAFT ADVISORY IS NOT ANTICIPATED...WE WILL HAVE TO WATCH THE BEACH HAZARD POTENTIAL /PRIMARILY INCREASING LONG SHORE CURRENTS/ AS IT EVOLVES THIS AFTERNOON AND EVENING. && .HYDROLOGY... ISSUED AT 330 AM EDT MON JUL 22 2013 NO HYDRO ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...TJT SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MJS AVIATION...NJJ HYDROLOGY...LAURENS MARINE...TJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
101 PM CDT MON JUL 22 2013 .UPDATE... FOR 18Z AVIATION DISCUSSION BELOW && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT MON JUL 22 2013 EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE 22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY /MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35. CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT. HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 359 AM CDT MON JUL 22 2013 MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT. THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH SATURDAY. AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF THE BUNCH. FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE. ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH. IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE 22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE ABLE MAKE A RUN AT THAT RECORD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1245 PM CDT MON JUL 22 2013 THE COLD FRONT NOW EXTENDS FROM ROUGHLY SIOUX FALLS...TO THE WESTERN TWIN CITIES METRO...TO JUST SOUTHEAST OF DULUTH. SO FAR...THE FRONT IS JUST MANAGING TOWERING CUMULUS CLOUDS WITH CLOUDS BASES NEAR 3000 FT IN MOST LOCATIONS. A BRIEF PERIOD /1-3 HOURS/ OF MVFR CEILINGS IS POSSIBLE WITH THE COLD FRONT. WE ARE ALSO SEEING SOME SHOWERS DEVELOP IN NORTHWEST WI...BUT MINNESOTA AND WESTERN CENTRAL WI REMAIN STORM FREE AT THIS POINT. KEAU HAS THE BEST CHANCE FOR THUNDER. WE NOW THINK STORMS WILL MISS ALL THE OTHER TAF SITES BESIDES KEAU. KMSP... THE COLD FRONT /WITH A WIND SHIFT TO THE W-NW/ PASSED BY THE OFFICE HERE IN CHANHASSEN AT ABOUT 1245 PM...SO IT WILL BE AT THE AIRPORT WITHIN 30 MINUTES OR SO. GIVEN THAT THE STORM ACTIVITY HAS BEEN SUPPRESSED UP UNTIL NOW...WE THINK THERE IS NOT ENOUGH TIME TO DEVELOP STORMS BEFORE THE COLD FRONT PASSES THROUGH. STORM CHANCES LOOK BETTER 50-75 MILES EAST OF THE AIRPORT. COULD HAVE LINGERING STRATO CU WITH A SCT-BKN 2500-3500 FT DECK LATE THIS AFTERNOON OR EARLY EVENING...BUT THE MORE WIDESPREAD CLOUDS SHOULD REMAIN IN NORTHERN/WESTERN MN. NO AVIATION WEATHER CONCERNS TOMORROW. /OUTLOOK FOR KMSP/ TUE/TUE NIGHT...VFR. WINDS N 5 TO 10 KT. WED...VFR. CHANCE OF SHRA/TSRA LATE NIGHT. WINDS S 5 KT. THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS WSW 5 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...MPG AVIATION...CLF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1239 PM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 911 AM CDT MON JUL 22 2013 FIRST FORECAST UPDATE OF THE DAY HAS BEEN SENT. IN SHORT...ANOTHER TRICKY DAY/EVENING OF THUNDERSTORM CHANCES AWAITS THE LOCAL AREA. ESSENTIALLY...THE ONLY NOTABLE CHANGE FROM PREVIOUS FORECAST SO FAR WAS TO TRIM CENTRAL/NORTHEAST PORTIONS OF THE CWA FROM ANY THUNDERSTORM MENTION THIS MORNING...WHILE LEAVING MORNING CHANCES INTACT IN KS ZONES...AND MAINLY WEST OF A GOTHENBURG-ALMA LINE IN NEBRASKA TO ACCOUNT FOR THE FAIRLY PERSISTENT NARROW NORTHWEST- SOUTHEAST AXIS OF CONVECTION PRIMARILY AFFECTING FURNAS COUNTY AT THIS TIME. OTHER THAN MAYBE SOME SMALL HAIL...NOT EXPECTING A MORNING SEVERE THREAT. FOR THIS AFTERNOON...ITS HARD TO ARGUE WITH THE SPC SLIGHT RISK FOR ROUGHLY THE SOUTHEAST 2/3 OF THE CWA...ALTHOUGH ITS TOUGH TO SAY WHETHER WE MIGHT ONLY GET 1 OR 2 ISOLATED STRONG-SEVERE STORMS...OR POTENTIALLY MORE SCATTERED COVERAGE. EITHER WAY...THE PRIMARY FORCING MECHANISM ALOFT LOOKS TO BE A FAIRLY SUBTLE SHORTWAVE TROUGH DRIFTING EAST-SOUTHEAST OUT OF WYOMING...WHILE AT THE SURFACE A FAIRLY WEAK COLD FRONT WILL SINK SOUTHWARD INTO PARTS OF THE CWA AS THE DAY WEARS ON...PROVIDING AT LEAST LIMITED LOW-LEVEL CONVERGENCE. THE LATEST RAP FORECAST VALID FOR 21Z/4PM PAINTS 1000-2500 J/KG OF 0-1KM MLCAPE ACROSS MOST OF THE CWA...HIGHEST IN THE SOUTH...IN THE PRESENCE OF DECENT 0-6KM DEEP LAYER SHEAR OF 35-40KT...SO CERTAINLY A THREAT FOR SOME SOUTHEAST-MOVING STRONG TO SEVERE STORMS AND POTENTIALLY SUPERCELLS EXISTS...ALTHOUGH WORKING AGAINST STORM FORMATION APPEARS TO BE AT LEAST A WEAK CAP EVIDENT ON FORECAST SOUNDINGS AROUND 700-650 MILLIBARS...SO ITS ALSO NOT OUT OF THE QUESTION THAT OUR LOCAL AREA COULD LARGELY STEER CLEAR OF AN AFTERNOON/EVENING STORM THREAT...WITH BETTER CHANCES POTENTIALLY FOCUSING JUST TO OUR SOUTH/EAST. EVEN THOUGH THE GREATEST SEVERE THREAT WOULD THEORETICALLY FOCUS ACROSS SOUTHERN PORTIONS OF OUR AREA...HAVE PUT AT LEAST A SLIGHT CHANCE OF STORMS EVEN IN FAR NORTHERN COUNTIES FOR AT LEAST A FEW HOURS THIS AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CDT MON JUL 22 2013 THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR FLOW. THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND 06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY THEN. THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST STORMS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND TEMPERATURES. MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A LITTLE DIFFERENT WITH EACH MODEL. THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE AREA. TEMPERATURES WILL BE COOLER THAN TODAY. A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY. TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME LINGERING THUNDERSTORMS. FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER SIDE DURING THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1239 PM CDT MON JUL 22 2013 AS A RESULT OF THIS PESKY NORTHWESTERLY FLOW ALOFT...THE CHALLENGE HERE DURING THIS TAF PERIOD IS DETERMINING PRECIPITATION CHANCES OVER THE TERMINAL. THUNDERSTORMS CANNOT BE COMPLETELY RULED OUT TODAY/TONIGHT...HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH AT THE MOMENT TO PUT A MENTION IN THE TAF. WILL AMEND IF CONDITIONS CHANGE. WITH THAT BEING SAID...VFR CONDITIONS SHOULD PREVAIL AT THE TERMINAL SITE. THE WIND WILL REMAIN FROM THE NORTH FOR THE FIRST SEVERAL HOURS AS A COLD FRONT SLIDES THROUGH THE REGION...BUT THE WIND SHOULD SHIFT AND BECOME MORE WESTERLY AS WE PROGRESS THROUGH OVERNIGHT PERIOD. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...WESELY LONG TERM...JCB AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1112 AM CDT MON JUL 22 2013 .UPDATE... UPDATED FOR CONVECTIVE TRENDS THROUGH THE DAY && .DISCUSSION... 12Z UPPER AIR ANALYSIS INDICATED A POTENT UPPER LEVEL SYSTEM MOVING THROUGH SRN CANADA ASSOCIATED WITH AN 80 KT H3 JET AND 50 M H5 HEIGHT FALLS. THIS WAS ALLOWING FOR A COLD FRONT TO PUSH SEWD INTO THE FA THIS MORNING...AND EXTENDED FROM NEAR SUX TO ODX AT 15Z. THERE WAS ALSO A 60 KT JET SEGMENT ASSOCIATED WITH A SUBTLE SHRTWV TROUGH OVER ERN WY. MID-LEVEL LAPSE RATES HAD IMPROVED OVER THE LAST 24 HOURS ACROSS THE CENTRAL PLAINS WITH H7 TO H5 DELTA-T VALUES OF +20 C FROM OAX UPSTREAM TO RAP/LBF AND INTO THE ROCKIES. A NWRLY H85 WND AHEAD OF THE COLD FRONT HAD PUSHED THE MOISTURE AXIS TO THE S AND E OF OAX...BUT +15 C H85 DEW POINTS WERE NOTED ALONG AND JUST BEHIND THE FRONT /INCLUDING A 16 C H85 DEW POINT AT RAP/. THE COMBINATION OF THE BETTER MID LEVEL LAPSE RATES AND MOISTURE ALONG THE FRONT WILL LEAD TO A STRONGLY UNSTABLE ATMOSPHERE ACROSS THE FA THIS AFTERNOON WITH MLCAPE APPROACHING 3500 J/KG...WHICH APPEARS REASONABLE GIVEN THE MODIFIED KOAX 12Z SOUNDING. KOAX 88-D CONTS TO INDC SOME SCT TSRA JUST BEHIND THE SFC BOUNDARY MOVING INTO NE NEB LATE THIS MORNING AND WE FEEL THIS ACTIVITY WILL CONT TO DRIFT TO THE SE THRU THE AFTN. THIS ACTIVITY IS CURRENT ELEVATED ABOVE THE NOCTURNAL INVERSION WITH A LIKELY EFFECTIVE INFLOW LAYER JUST ABOVE 850 MB. THIS ACTIVITY WAS HANDLED WELL BY GOING FORECAST REQUIRING LITTLE CHANGE. THE MAIN NEGATIVE THAT WILL LIKELY KEEP CONVECTIVE COVERAGE FAIRLY ISOLATED TODAY IS THE LACK OF MORE ORGANIZED LARGE-SCALE ASCENT AND RATHER WEAK SFC CONVERGENCE ALONG THE FRONT. THE WY SHRTWV TROUGH WILL LIKELY AFFECT WRN NEB INTO KS AND THE CANADIAN SHRTWV SHOULD STAY WELL TO THE NORTH. THUS THE BEST COVERAGE IS LIKELY TO BE IN WRN IA AND WE WILL CENTER THE HIGHEST POPS THERE WITH MORE ISOLATED ACTIVITY IN E-CNTRL AND SE NEB. THERE IS SOME THREAT OF AN ISO SVR STORM TODAY...BUT WEAK EFFECTIVE SHEAR /GENERALLY LESS THAN 20 KT/ SHOULD KEEP ANY THREAT ISOLATED AND SHORT-LIVED. THE BETTER DEEP LAYER SHEAR /> 30 KT/ WILL ACTUALLY BE OVER THE SRN CWA IF CONVECTION CAN MAKE IT INTO THAT AREA LATE THIS AFTN AND EVENING. ALL THE ACTIVITY WILL LIKELY PUSH OUT OF THE AREA BY MID EVENING...BUT ANOTHER SHRTWV TROUGH /SEEN IN THE 12Z UPPER AIR ANALYSIS OVER WA/ MAY LEAD TO CONVECTION ROLLING OFF THE HIGH PLAINS OVERNIGHT AND THIS WILL BE DISCUSSED MORE IN THE AFTERNOON AFD. BOUSTEAD && .AVIATION... 18Z TAFS FOR KOMA...KOFK...KLNK VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD EXCEPT IN POSSIBLE TSRA. THIS APPEARS MOST LIKELY AT OMA FROM AROUND 19-22Z AND LNK AROUND 21-24Z WITH MVFR CIGS/VISBY POSSIBLE. OTHERWISE A SFC CDFNT WILL MOV THROUGH OFK NEAR 18Z AND OMA/LNK BY AROUND 21Z WITH WINDS SHIFTING FROM SW TO NW AT ALL LOCATIONS. MOST CLEAR CONDITIONS ARE EXPECTED OVERNIGHT WITH LIGHT WINDS. && PREV DISCUSSION... /ISSUED 304 AM CDT MON JUL 22 2013/ DISCUSSION... PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35 KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING. SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED TUESDAY AS WELL. THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A SMALL PRECIP CHANCE SUNDAY INTO MONDAY. DEWALD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
637 PM EDT MON JUL 22 2013 .SYNOPSIS... A TROF OF LOW PRESSURE WILL LINGER INLAND THROUGH TUESDAY. A COLD FRONT WILL SLOWLY PUSH THROUGH WEDNESDAY AND WEDNESDAY NIGHT...BECOMING STATIONARY NEAR THE COAST THURSDAY AND FRIDAY. THE FRONT WILL DISSIPATE ON SATURDAY WITH ANOTHER COLD FRONT APPROACHING FROM THE NORTHWEST MONDAY. && .NEAR TERM /THROUGH TUESDAY/... AS OF 630 PM MONDAY...A DEEP MID-LEVEL TROUGH LIES ACROSS THE TENNESSEE VALLEY WITH HIGH PRESSURE CONTINUE OVER THE CENTRAL ATLANTIC. THIS CONTINUES TO CIRCULATE VERY MOIST AIR INTO EASTERN NORTH CAROLINA AS LATEST MESOANALYSIS GRAPHICS INDICATES PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES AREA-WIDE. THE 3 KM HRRR HAS ONCE AGAIN TODAY HAD THE BEST DEPICTION OF THE LOCATION OF PRECIPITATION AND GENERALLY SHOWS ACTIVITY LINGERING ACROSS THE CENTRAL AND WESTERN COASTAL PLAINS FOR A FEW MORE HOURS BEFORE GRADUALLY DISSIPATING LATER TONIGHT AND HAVE SHOWN CHANCE POPS INLAND TO SLIGHT CHANCE COAST THROUGH THE BALANCE OF THE EVENING. MADE NO CHANGES TO CURRENT MINIMUM TEMPERATURE FORECAST WITH LOWS PREDICTED IN THE 72 TO 77 DEGREE RANGE CWA WIDE. && .SHORT TERM /TUESDAY NIGHT THROUGH 6 PM TUESDAY/... AS OF 230 PM MON...TROUGHING INLAND AND HIGH PRESSURE OFF THE SE COAST WILL CONTINUE TUE. SCT CONVECTION EXPECTED AGAIN...MAINLY DIURNAL DRIVEN BY SEABREEZE AND SHORTWAVE APPROACHING FROM THE WEST. FORECAST SOUNDINGS A BIT DRIER THAN PAST SEVERAL DAYS. AN ISOLATED STRONG STORM WILL BE POSSIBLE AS SHEAR INCREASES...WITH GUSTY WINDS...HEAVY RAIN...AND FREQ LIGHTNING. LOW LEVEL THICKNESS VALUES AND TEMPS ALOFT SUPPORT HIGHS IN THE UPPER 80S TO LOWER 90S. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... AS OF 215 PM MON...SIGNIF MDL DIFFERENCES CONT AND LEANED A BIT MORE TWRD ECMWF AND AWAY FROM GFS. UPR TRF WILL DEVELOP TO THE W MID WEEK THEN SWING THRU FRI/FRI NIGHT. ANOTHER PIECE OF ENERGY WILL MOVE THRU THE TRF OVER THE WEEKEND AND SWING N OF THE AREA EARLY NEXT WEEK. WEAK FRONT WILL MOVE INTO THE AREA LATER WED AND DRIFT TO THE CST THU BEFORE STALLING NEAR THE CST FRI INTO SAT. THE INIT FRONT WILL DISSIPATE SUN THEN ANOTHER COLD FRONT ASSOC WITH THE SECOND UPR TRF WILL APPROACH FROM THE W MON. APPEARS MOST OF TUE NIGHT AND WED WILL BE RAIN FREE AS ATMS DRIES A BIT IN WAKE OF SRT WAVE....DID KEEP SLIGHT POPS IN. POPS INCREASE WED NIGHT AND THU WITH FRONT IN THE AREA AND APPROACHING UPR TRF...FOR NOW KEPT POPS IN CHC RANGE...LATER SHIFTS CAN BUMP UP IF MDLS BECOME MORE SIMILAR. SCT CONVECTION WILL CONT FRI WITH THE FRONT STALLED IN THE VCNTY AND UPR TRF CROSSING. LOOKS A BIT DRIER OVER THE WEEKEND AS INIT TRF SHIFTS OFF THE CST. COULD SEE A BIT BETTER CVRG LATER SUN AND MON AS SECOND TRF APPROACH AND PASSES TO THE N. TEMPS WILL REMAIN NEAR NORMAL WED WITH LOWER 90S INLAND AND MID/UPR 80S CST. WITH FRONT IN AREA AND FALLING HGTS EXPECT SLIGHTLY COOLER TEMPS REST OF THE PERIOD WITH HIGHS IN THE 80S. DESPITE POSS OF SOME N/NE WINDS LOOKS LIKE DEWPTS WILL MAINLY STAY AOA 70 KEEPING LOW IN THE 70S AREA-WIDE. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... SHORT TERM /THROUGH TUESDAY/... AS OF 230 PM MON...SCT SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE CENTRAL CWA. KEWN AND KISO HAVE ALREADY HAD SHOWERS AND KPGV COULD ALSO CATCH A SHOWER IN THE NEXT HOUR OR TWO. EXPECT ACTIVITY TO WANE WITH LOSS OF HEATING. MAIN QUESTION WILL BE IF STRATUS FORMS LATE TONIGHT AND ITS EXTENT. SINCE RAINFALL HAS ALREADY OCCURRED AT KEWN AND KISO AND SHOWERS WILL BE NEAR KPGV FOR THE NEXT COUPLE OF HOURS...WILL HIT THE STRATUS A BIT HARDER AT THESE SPOTS...WITH CEILINGS NOT QUITE AS LOW AT KOAJ. DIURNAL CONVECTION LIKELY AGAIN TUE AFTERNOON/EVENING. SWLY WINDS WILL CONTINUE WITH GUSTS 15-20KT TUE AFTERNOON. LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 215 PM MON...WL LIKELY HAVE BOUTS OF LATE NIGHT/EARLY MORN ST/SCU WITH CIGS IN THE MVFR TO IFR RANGE AT TIMES...POSS SOME PATCHY FOG AS WELL. DURING THE DAY/EVENING EXPECT MAINLY VFR...HOWEVER SCT CONVECTION WILL LEAD TO BRIEF PDS OF REDUCED FLIGHT CATEGORIES THRU THE PERIOD. && .MARINE... SHORT TERM /THROUGH TUESDAY/... AS OF 635 PM MON...MODERATE SOUTHWEST WINDS OF 10 TO 20 KNOTS CONTINUE OVER THE COASTAL WATERS AND SOUNDS WITH SEAS GENERALLY 2 TO 4 FEET UP NORTH AND 3 TO 5 FEET SOUTH. ONLY MINOR TWEAKS MADE TO CURRENT MARINE FORECAST. TIGHTENED GRADIENT WILL CONTINUE TUE WITH WINDS 10-20KT AND GUSTS TO 25KT SOUTH OF OREGON INLET...WITH SEAS BUILDING TO 6FT ON THE OUTER WATERS. ISSUED SCA FOR WATERS SOUTH OF OREGON INLET BEGINNING TUE INTO TUE NIGHT. LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 215 PM MON...GUSTY SOUTH TO SOUTHWEST WED TUE EVENING WILL DIMINISH INTO WED AS WEAK FRONT DRIFTS INTO THE REGION. SCA WILL CONT MOST CSTL WTRS TUE EVENING THEN SEAS SHLD DROP BELOW 6 FT ALL WTRS BY LATER TUE NIGHT. WIND DIR TOUGH THRU REST OF PD WITH FRONTAL POSITION KEY...LEANED TWRD ECMWF/SREF WITH MAINLY LIGHT ONSHORE FLOW NRN TIER AND LIGHT/VRBL SRN TIER THRU FRI. AS FRONT DISSIPATES SAT WINDS WILL BECOME MORE SRLY. WITH FRONT NEAR CST GRDNT SHLD BE LOOSE WITH LIGHT WINDS WED INTO SAT. SEAS WILL DROP TO 2 TO 4 FEET LATER WED AND STAY IN THE 2 TO 3 FOOT RANGE THU INTO SAT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM TUESDAY TO 7 AM EDT WEDNESDAY FOR AMZ152-154. SMALL CRAFT ADVISORY FROM 11 AM TUESDAY TO 2 AM EDT WEDNESDAY FOR AMZ156-158. && $$ SYNOPSIS...CQD NEAR TERM...CTC SHORT TERM...CQD LONG TERM...RF AVIATION...CTC/RF/CQD MARINE...CTC/RF/CQD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
317 PM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 250 PM MONDAY... THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT... AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS. THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF 2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z... AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED (AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING... WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE... 69-73. FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE... FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER. EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG OVERNIGHT. -GIH && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 PM MONDAY... A PAIR OF SHORTWAVE TROUGHS ALOFT...BOTH EMBEDDED WITHIN A SHEAR AXIS STRETCHING FROM SOUTH-CENTRAL CANADA TO THE RELATIVELY DATA-SPARSE EASTERN PACIFIC...WILL CROSS THE MIDDLE ATLANTIC AND CAROLINAS THIS PERIOD - SEPARATED BY ABOUT 24 HOURS AND BOTH WITH FAVORABLE DIURNAL TIMING FOR ENHANCED THUNDERSTORM COVERAGE EACH AFTERNOON-EVENING. MEANWHILE AT THE SURFACE...A COLD FRONT STRETCHING FROM THE UPPER MIDWEST TO THE CENTRAL PLAINS THIS AFTERNOON WILL CREST THE APPALACHIANS AND MERGE WITH A LEE TROUGH BY LATE WED...THEN DRIFT SLOWLY SOUTHEASTWARD INTO EASTERN NC BY THU. WED AND WED NIGHT: SCATTERED THUNDERSTORMS ARE ACCORDINGLY EXPECTED TO MAXIMIZE ALONG AND EAST OF THE MERGED SURFACE FRONT/TROUGH...WITH LESSER COVERAGE OVER THE WESTERN PIEDMONT WHERE LOW LEVEL WNW FLOW AND LOWER-MIDDLE 60S SURFACE DEWPOINTS ARE FORECAST TO PREVAIL. PROJECTED 15-25 KTS OF DEEP LAYER SHEAR FAVORS MULTI-CELL CLUSTERS CAPABLE OF KNOCKING DOWN A FEW TREES...AND PRODUCING LOCALLY HEAVY RAIN. SHOWERS AND STORMS ARE APT TO LINGER INTO THE FIRST HALF OF THE NIGHT IN THE COASTAL PLAIN...INVOF THE SURFACE BOUNDARY AND PROBABLE OUTFLOW... BEFORE THE PARENT SHORTWAVE TROUGH AND ASSOCIATED LARGER SCALE FORCING FOR ASCENT LIFT NORTHEAST OF OUR REGION..AND NOCTURNAL COOLING/PRIOR CONVECTIVE OVERTURNING STABILIZES THE ENVIRONMENT. WARM WITH HIGHS 89 TO 94...AND LOWS IN THE UPPER 60S TO LOWER 70S. THU AND THU NIGHT: NWP GUIDANCE HAS TRENDED MORE AMPLIFIED WITH THE SECOND SHORTWAVE TROUGH FOR THU. SO WHILE THE BEST LOW LEVEL CONVERGENCE AND MOISTURE WILL EXIST OVER SOUTHEASTERN NC...LOW LEVEL MOISTURE ON THE COOL SIDE OF THE FRONT - IN STILL RELATIVELY-MOIST NORTHEAST FLOW WITH DEWPOINTS IN THE UPPER 60S - WILL LIKELY PROVE SUPPORTIVE OF SCATTERED TO PERHAPS NUMEROUS STORMS FROM NEAR KMEB TO KGSB...WITH MORE WIDELY SCATTERED DEVELOPMENT TO THE NORTHWEST. COOLER IN THE AFOREMENTIONED POST-FRONTAL NE FLOW...WITH HIGHS RANGING FROM THE LOWER 80S NW PIEDMONT TO UPPER 80S SANDHILLS AND SOUTHERN COASTAL PLAIN. LOWS AGAIN GENERALLY INT HE UPPER 60S TO LOWER 70S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 315 PM MONDAY... IT STILL APPEARS THAT THE BEGINNING OF THE MEDIUM RANGE (FRI-SAT) WILL FEATURE SHORTWAVE RIDGING AND THE LOWEST PROBABILITY OF PRECIPITATION DURING THE PERIOD...WITH RELATIVE HIGHEST PROBABILITIES (30 PERCENT) OVER THE SOUTHERN TIER...WHERE BOUNDARY LAYER MOISTURE WILL BE HIGHEST INVOF THE OLD...DIFFUSING SURFACE FRONT. HIGHS WITHIN A FEW DEGREES OF 85..AND LOWS IN THE UPPER 60S TO LOWER 70S. THE SECOND HALF OF THE MEDIUM RANGE (SUN-MON) WILL FEATURE RENEWED TROUGH AMPLIFICATION ALOFT...AND THE ARRIVAL OF AN ACCOMPANYING SURFACE FRONTAL ZONE INTO THE EASTERN US. MOIST AND PERTURBED SOUTHWEST FLOW ALOFT...IN A REGION OF PERSISTENT UPPER DIVERGENCE IN THE ENTRANCE REGION OF AN ACCOMPANYING UPPER JET AND WITH LOW LEVEL CONVERGENCE ALONG THE SLOWLY-PASSING SURFACE FRONT...FAVOR A GOOD TO LIKELY CHANCE OF SHOWERS AND STORMS MAXIMIZED WITH DIURNAL HEATING. NEARLY PERSISTENCE TEMPERATURES WITHIN A FEW DEGREES OF 85...AND UPPER 60S TO LOWER 70S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 1230 PM MONDAY... MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE... SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED 02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT. LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/ STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD SHORT TERM...MWS LONG TERM...MWS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
304PM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 250 PM MONDAY... THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT... AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS. THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF 2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z... AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED (AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING... WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE... 69-73. FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE... FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER. EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG OVERNIGHT. -GIH && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 PM MONDAY... A PAIR OF SHORTWAVE TROUGHS ALOFT...BOTH EMBEDDED WITHIN A SHEAR AXIS STRETCHING FROM SOUTH-CENTRAL CANADA TO THE RELATIVELY DATA-SPARSE EASTERN PACIFIC...WILL CROSS THE MIDDLE ATLANTIC AND CAROLINAS THIS PERIOD - SEPARATED BY ABOUT 24 HOURS AND BOTH WITH FAVORABLE DIURNAL TIMING FOR ENHANCED THUNDERSTORM COVERAGE EACH AFTERNOON-EVENING. MEANWHILE AT THE SURFACE...A COLD FRONT STRETCHING FROM THE UPPER MIDWEST TO THE CENTRAL PLAINS THIS AFTERNOON WILL CREST THE APPALACHIANS AND MERGE WITH A LEE TROUGH BY LATE WED...THEN DRIFT SLOWLY SOUTHEASTWARD INTO EASTERN NC BY THU. WED AND WED NIGHT: SCATTERED THUNDERSTORMS ARE ACCORDINGLY EXPECTED TO MAXIMIZE ALONG AND EAST OF THE MERGED SURFACE FRONT/TROUGH...WITH LESSER COVERAGE OVER THE WESTERN PIEDMONT WHERE LOW LEVEL WNW FLOW AND LOWER-MIDDLE 60S SURFACE DEWPOINTS ARE FORECAST TO PREVAIL. PROJECTED 15-25 KTS OF DEEP LAYER SHEAR FAVORS MULTI-CELL CLUSTERS CAPABLE OF KNOCKING DOWN A FEW TREES...AND PRODUCING LOCALLY HEAVY RAIN. SHOWERS AND STORMS ARE APT TO LINGER INTO THE FIRST HALF OF THE NIGHT IN THE COASTAL PLAIN...INVOF THE SURFACE BOUNDARY AND PROBABLE OUTFLOW... BEFORE THE PARENT SHORTWAVE TROUGH AND ASSOCIATED LARGER SCALE FORCING FOR ASCENT LIFT NORTHEAST OF OUR REGION..AND NOCTURNAL COOLING/PRIOR CONVECTIVE OVERTURNING STABILIZES THE ENVIRONMENT. WARM WITH HIGHS 89 TO 94...AND LOWS IN THE UPPER 60S TO LOWER 70S. THU AND THU NIGHT: NWP GUIDANCE HAS TRENDED MORE AMPLIFIED WITH THE SECOND SHORTWAVE TROUGH FOR THU. SO WHILE THE BEST LOW LEVEL CONVERGENCE AND MOISTURE WILL EXIST OVER SOUTHEASTERN NC...LOW LEVEL MOISTURE ON THE COOL SIDE OF THE FRONT - IN STILL RELATIVELY-MOIST NORTHEAST FLOW WITH DEWPOINTS IN THE UPPER 60S - WILL LIKELY PROVE SUPPORTIVE OF SCATTERED TO PERHAPS NUMEROUS STORMS FROM NEAR KMEB TO KGSB...WITH MORE WIDELY SCATTERED DEVELOPMENT TO THE NORTHWEST. COOLER IN THE AFOREMENTIONED POST-FRONTAL NE FLOW...WITH HIGHS RANGING FROM THE LOWER 80S NW PIEDMONT TO UPPER 80S SANDHILLS AND SOUTHERN COASTAL PLAIN. LOWS AGAIN GENERALLY INT HE UPPER 60S TO LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... WEDNESDAY THROUGH THURSDAY: THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC STATES. DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN NC. NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE. FRIDAY THROUGH SUNDAY: FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE... WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING. ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65 TO 70. TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO 30 PERCENT. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 1230 PM MONDAY... MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE... SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED 02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT. LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/ STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD SHORT TERM...MWS LONG TERM...CBL AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
253 PM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 250 PM MONDAY... THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT... AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS. THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF 2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z... AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED (AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING... WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE... 69-73. FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE... FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER. EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG OVERNIGHT. -GIH && .SHORT TERM / /... AS OF 300 AM MONDAY... TO BE UPDATED SHORTLY. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... WEDNESDAY THROUGH THURSDAY: THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC STATES. DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN NC. NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE. FRIDAY THROUGH SUNDAY: FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE... WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING. ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65 TO 70. TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO 30 PERCENT. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 1230 PM MONDAY... MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE... SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED 02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT. LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/ STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD SHORT TERM...WSS LONG TERM...CBL AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1230 PM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM MONDAY... REST OF TODAY: VERY MOIST AIR MASS IN PLACE AS NOTED BY 12Z GSO/MHX SOUNDINGS AND BLENDED TPW IMAGERY... WITH PW RANGING FROM 2.0-2.2 INCHES WEST TO EAST... ALTHOUGH VALUES ARE SLIGHTLY LOWER TO OUR WEST. LATEST SURFACE ANALYSIS SHOWS THE NEARLY STATIONARY SYNOPTIC FRONTAL ZONE FROM IA EAST ACROSS NRN IL/IN/OH TO PA/MA. A WEAK LOW IS EVIDENT OVER SCENTRAL VA WITH TRAILING WEAK TROUGHING THROUGH CENTRAL NC... AND A MORE PROMINENT LOW AND TROUGH OVER SRN IL/SE MO/NW AR. THE LATTER FEATURE IS ASSOCIATED WITH A POTENT MID LEVEL SHORTWAVE TROUGH THAT IS ON PACE TO APPROACH OUR AREA LATE TONIGHT. ANOTHER UPPER LEVEL WAVE NOW OVER THE AL/GA BORDER IS EXPECTED TO TRACK ACROSS FAR SRN AND SE NC THIS EVENING. MODELS ARE NOT IN GREAT AGREEMENT ON THE TIMING AND EXTENT OF CONVECTION THIS AFTERNOON/ EVENING. THE 4KM WRF-ARW/WRF-NMM AND HRRR DEPICT JUST SCATTERED COVERAGE IN THE EARLY AFTERNOON IN THE ERN CWA... WHERE THE CINH HAS VANISHED AND WHERE MLCAPE HAS ALREADY CLIMBED NEAR 1000 J/KG. BUT THE DEEP LAYER SHEAR IS QUITE POOR (UNDER 15 KTS) AND EXPECTED TO REMAIN SO THROUGH THE DAY... NOT SUPPORTIVE OF STRONG ORGANIZED CONVECTION. PW WILL ALSO BE DROPPING A BIT THIS AFTERNOON... AND THE STRONG MISS VALLEY WAVE SHIFTING EASTWARD MAY HELP DEAMPLIFY THE AL/GA WAVE AS IT CROSSES THE CAROLINAS. WILL ADJUST POPS A BIT THROUGH THE AFTERNOON TO FOCUS THE BETTER COVERAGE (30-40%) IN THE EAST... WHERE MOISTURE AND INSTABILITY IS EXPECTED TO BE BETTER BENEATH WEAK UPPER-LEVEL DPVA... WITH LOWER POPS OF 20-30% IN THE WRN CWA. LOCALLY HEAVY RAIN IS STILL POSSIBLE WITH WARM LAYERS (LCL-0C) OF 3.5-3.8 KM... AND ANY ADDITIONAL RAIN IN AREAS THAT SAW A LOT YESTERDAY (SUCH AS THE GREENSBORO AREA) COULD EASILY SEE QUICK FLOODING TODAY. FREQUENT LIGHTNING IS STILL A SECONDARY CONCERN... ALTHOUGH THE MARGINAL -10C TO -30C CAPE PEAKING AT 500 J/KG IS NOT AS HIGH AS IN SOME OF THE PROLIFIC LIGHTNING EVENTS WE`VE HAD RECENTLY. TEMP RISE SO FAR HAS BEEN GREATLY TEMPERED BY STUBBORN STRATOCU OVER MUCH OF CENTRAL NC... WITH ONLY ERN/SRN SECTION SEEING SOME HOLES IN THE CLOUDS. EXPECT THIS WILL START TO MIX OUT SHORTLY (BASED ON PILOT REPORTS THAT THIS DECK IS 500-1000 FT THICK)... BUT WITH THE DELAYED INSOLATION... WILL STILL NEED TO TRIM A FEW DEGREES OFF HIGHS... GOING WITH 85-90. -GIH WHILE BULK OF CONVECTION WILL DIMINISH IN THE EVENING WITH LOSS OF HEATING...APPROACH OF THE MID-UPPER LEVEL TROUGH WILL LIKELY MAINTAIN A FEW SHOWERS/STORMS INTO THE OVERNIGHT HOURS. CONTINUED MUGGY TONIGHT WITH MIN TEMPS NEAR 70-LOWER 70S. -WSS && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 300 AM MONDAY... EXPECT A CONTINUATION OF THE UNSETTLED WEATHER PATTERN TUESDAY DUE TO PRESENCE OF MID-UPPER LEVEL TROUGH OVER THE CAROLINAS THOUGH FOCUS MAY BE MORE IN THE EAST VERSUS WEST. SHORT TERM MODEL GUIDANCE SUGGEST WESTERLY 850MB FLOW DEVELOPING LATE TODAY INTO TUESDAY WITH A 850MB TROUGH CROSSING THE REGION TUESDAY AFTERNOON. RH CROSS SECTION SUGGEST THE AIR MASS DRYING OUT ABOVE 700MB/10K FT DURING THE COURSE OF THE AFTERNOON...ESPECIALLY WEST OF HIGHWAY 1. THE DOWNSLOPE FLOW IN THE WAKE OF THIS SYSTEM AND AN AIR MASS NOT AS MOIST MAY LIMIT/INHIBIT CONVECTIVE DEVELOPMENT IN THE WEST ON TUESDAY. WITH TROUGH CROSSING THE EAST DURING MAX HEATING...STILL EXPECT AT A MINIMUM 50 PERCENT COVERAGE. PRESENCE OF DRIER AIR ALOFT MAY LEAD TO EVAPORATIVE COOLING IN VICINITY OF THUNDERSTORM DOWNDRAFTS...LEADING TO STRONG/LOCALLY DAMAGING WINDS WITH THE STRONGER CELLS. MAJORITY OF THE CONVECTION WILL DISSIPATE SHORTLY AFTER SUNSET THOUGH THE APPROACH OF A SECONDARY TROUGH IN THE FLOW ALOFT MAY TRIGGER ADDITIONAL ACTIVITY LATE TUESDAY NIGHT-EARLY WEDNESDAY MORNING. THE DRIER AIR MASS ALOFT SHOULD ALLOW FOR PERIODS OF PARTIAL SUNSHINE. THIS MAY LEAD TO AFTERNOON TEMPS A COUPLE OF DEGREES WARMER THAN TODAY. EXPECT MAX TEMPS NEAR 90 TO LOWER 90S AREAWIDE. MIN TEMPS NEAR 70-LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... WEDNESDAY THROUGH THURSDAY: THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC STATES. DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN NC. NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE. FRIDAY THROUGH SUNDAY: FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE... WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING. ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65 TO 70. TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO 30 PERCENT. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 1230 PM MONDAY... MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE... SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED 02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT. LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/ STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD/WSS SHORT TERM...WSS LONG TERM...CBL AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
601 PM EDT MON JUL 22 2013 .SYNOPSIS... MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS. && .NEAR TERM /THROUGH TUESDAY/... 6PM UPDATE...TWEAKED POP GRIDS THIS EVENING BASED ON CURRENT RADAR TRENDS. OTHERWISE...MADE NO MAJOR CHANGES TO THE FORECAST. PREVIOUS DISCUSSION FOLLOWS... WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT. UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF AREA AFTER 09Z WITH PCPN THREAT DIMINISHING. THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW FLOW ALOFT. ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... COLD FRONT SWINGS THROUGH TUESDAY NIGHT AS 5H TROF SWINGS THROUGH AT THE MID LEVELS. CARRIED LIKELY POPS AS THERE WILL BE DECENT DYNAMIC FORCING COUPLED WITH PLENTY OF A AVAILABLE MOISTURE. HOWEVER...CHANCES FOR SEVERE WEATHER ASSOCIATED WITH THIS FEATURE WILL BE LIMITED DUE TO THE LACK OF DAYTIME HEATING DURING THE OVERNIGHT HOURS. AS HIGH PRESSURE BUILDS IN WEDNESDAY...BULK OF MOISTURE WILL BE SHUNTED TO THE EAST...LEADING TO A DRYING TREND. SHOULD SEE A NOTICEABLE DECREASE IN CONVECTIVE ACTIVITY WEDNESDAY AND THURSDAY AS LOW AND MID LEVEL COOL POOL HELPS TO STABILIZE THE ATMOSPHERE. LEFT CHANCE POPS IN FOR MOUNTAINS AS HEATING IN ELEVATED TERRAIN COULD STILL LEAD TO SOME CONVECTIVE DEVELOPMENT. WILL SEE A COOLING TREND THIS PERIOD. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD. && .LONG TERM /FRIDAY THROUGH MONDAY/... DRIER AIR MOVES IN TO CLOSE OUT THE WEEK AS TROUGH DIGS OVER THE GREAT LAKES SATURDAY AND SUNDAY. GFS AND EURO MODELS HANDLING FEATURES IN SEPARATE FASHION AND DEFERRED TO HPC GRIDS FOR EXTENDED PERIOD. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA. MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY IN FOR NOW. LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03 CRW CONSISTENCY H H H H H H M M M M L L HTS CONSISTENCY H H H H M L M M M M L L BKW CONSISTENCY H H H H H H H H M M M H EKN CONSISTENCY H H H H M M H H H H L M PKB CONSISTENCY M M L L M M M H H L M M CKB CONSISTENCY M M M M H H M H M M L M AFTER 00Z WEDNESDAY... IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...KMC/30 NEAR TERM...SL/30 SHORT TERM...KMC LONG TERM...KMC AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
339 PM EDT MON JUL 22 2013 .SYNOPSIS... MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS. && .NEAR TERM /THROUGH TUESDAY/... WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT. UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF AREA AFTER 09Z WITH PCPN THREAT DIMINISHING. THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW FLOW ALOFT. ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... COLD FRONT SWINGS THROUGH TUESDAY NIGHT AS 5H TROF SWINGS THROUGH AT THE MID LEVELS. CARRIED LIKELY POPS AS THERE WILL BE DECENT DYNAMIC FORCING COUPLED WITH PLENTY OF A AVAILABLE MOISTURE. HOWEVER...CHANCES FOR SEVERE WEATHER ASSOCIATED WITH THIS FEATURE WILL BE LIMITED DUE TO THE LACK OF DAYTIME HEATING DURING THE OVERNIGHT HOURS. AS HIGH PRESSURE BUILDS IN WEDNESDAY...BULK OF MOISTURE WILL BE SHUNTED TO THE EAST...LEADING TO A DRYING TREND. SHOULD SEE A NOTICEABLE DECREASE IN CONVECTIVE ACTIVITY WEDNESDAY AND THURSDAY AS LOW AND MID LEVEL COOL POOL HELPS TO STABILIZE THE ATMOSPHERE. LEFT CHANCE POPS IN FOR MOUNTAINS AS HEATING IN ELEVATED TERRAIN COULD STILL LEAD TO SOME CONVECTIVE DEVELOPMENT. WILL SEE A COOLING TREND THIS PERIOD. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD. && .LONG TERM /FRIDAY THROUGH MONDAY/... DRIER AIR MOVES IN TO CLOSE OUT THE WEEK AS TROUGH DIGS OVER THE GREAT LAKES SATURDAY AND SUNDAY. GFS AND EURO MODELS HANDLING FEATURES IN SEPARATE FASHION AND DEFERRED TO HPC GRIDS FOR EXTENDED PERIOD. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA. MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY IN FOR NOW. LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03 CRW CONSISTENCY H H H H H H M M M M L L HTS CONSISTENCY H H H H M L M M M M L L BKW CONSISTENCY H H H H H H H H M M M H EKN CONSISTENCY H H H H M M H H H H L M PKB CONSISTENCY M M L L M M M H H L M M CKB CONSISTENCY M M M M H H M H M M L M AFTER 18Z TUESDAY... IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...KMC/30 NEAR TERM...30 SHORT TERM...KMC LONG TERM...KMC AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
233 PM EDT MON JUL 22 2013 .SYNOPSIS... MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS. && .NEAR TERM /THROUGH TUESDAY/... WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT. UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF AREA AFTER 09Z WITH PCPN THREAT DIMINISHING. THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW FLOW ALOFT. ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... EXCEPT FOR THE NAM/SREF SUITE OF MODELS WHICH ARE SLOW OUTLIERS THERE IS GROWING AGREEMENT AMONG THE MODELS OF A FASTER PROGRESSION OF THE COLD FRONT TUESDAY NIGHT...AND OF A QUITE WEAK SECONDARY FRONT WEDNESDAY. FIRST...EXPECT A RAPID DECREASE IN CONVECTION TUESDAY AS AN UPPER DISTURBANCE EXITS AND TAKES MUCH OF THE RICH MOISTURE WITH IT. AGAIN...THE NAM IS A VERY SLOW OUTLIER EXITING THIS SYSTEM AND WAS NOT USED. WILL PAINT HIGH POPS EARLY IN MOUNTAINS BUT DECREASE THAT DURING TUESDAY MORNING. WILL KEEP LOWER POPS TUESDAY AFTERNOON WITH REMAINING LOW LEVEL MOISTURE AND HEATING TO DESTABILIZE THE ATMOSPHERE WELL AHEAD OF THE AFOREMENTIONED COLD FRONT...ESPECIALLY MOUNTAINS WITH AN ELEVATED HEAT SOURCE. WILL RAMP POPS UP AGAIN TUESDAY NIGHT WITH THE FRONT...GOING LIKELY FOR AN ORGANIZED BAND OF CONVECTION ALONG THE FRONT. HOWEVER...LESS RISK OF WATER PROBLEMS WITH THIS FEATURE AS PW`S WILL BE MUCH LESS THAN WE ARE CURRENTLY EXPERIENCING. WILL KEEP LOW POPS IN FOR MAINLY WEDNESDAY AFTERNOON AS THE SECONDARY FRONT DROPS SOUTHEASTWARD ACROSS THE AREA...MOSTLY IN MOUNTAINS. HIGH PRESSURE FINALLY BUILDS IN FOR THURSDAY WITH DRIER AND COOLER AIR BECOMING ESTABLISHED. STILL LINGER JUST A LOW CHANCE POP MOSTLY MOUNTAINS FOR AN AFTERNOON SHOWER PER SQUEEZING OUT ANY LINGERING LOW LEVEL MOISTURE WITH UPSLOPE FLOW AND MODEST COLD ADVECTION ALOFT. LOOK FOR A MODEST COOLING TREND THIS PERIOD...BUT A SIGNIFICANT DRYING OUT. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD. && .LONG TERM /FRIDAY THROUGH MONDAY/... STILL TRYING TO BRING DRIER AIR THURSDAY INTO FRIDAY. DEEPENING 500 MB TROF OVER EASTERN CANADA MAY PULL ANOTHER DISTURBANCES SE ON SATURDAY. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA. MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY IN FOR NOW. LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H M M M M HTS CONSISTENCY H H H H H H M L M M M H BKW CONSISTENCY H H H H H H H H H H M M EKN CONSISTENCY H H H H H H M M H H H H PKB CONSISTENCY H H M M L L H H H H H L CKB CONSISTENCY H M M M M M H H M H H H AFTER 18Z TUESDAY... IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...KMC/30 NEAR TERM...30 SHORT TERM...JMV LONG TERM...KTB AVIATION...30
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1242 PM CDT MON JUL 22 2013 .UPDATE... 18Z TAF DISCUSSION. && .AVIATION... MORNING MCS HAS GENERALLY FALLEN APART BUT SOME -SHRA WILL AFFECT CSV THROUGH THE AFTERNOON. SOME REDEVELOPMENT OF -SHRA IS POSSIBLE INTO THE EVENING AT CSV. CIGS RANGE FROM IFR AT CKV TO VFR AT CSV CURRENTLY...BUT GENERAL IMPROVEMENT TO MVFR THIS AFTERNOON AND VFR BY EVENING IS EXPECTED. THE WIDESPREAD RAINFALL SHOULD RESULT IN SOME FOG FORMATION AROUND SUNRISE TUESDAY MORNING WITH MVFR/IFR VIS. LIGHT SOUTHWEST TO WEST WINDS ARE ANTICIPATED THROUGHOUT THE TAF PERIOD. SHAMBURGER && .PREV DISCUSSION... /ISSUED 1022 AM CDT MON JUL 22 2013/ DISCUSSION... HAVE UPDATED ZONES AND GRIDS TO REDUCE POPS OVER THE NORTHWEST. RAIN IS BEGINNING TO TAPER OFF OVER THE NORTHWEST AND EXPECT THIS TREND WILL CONTINUE. BOYD PREV DISCUSSION... /ISSUED 922 AM CDT MON JUL 22 2013/ MESOSCALE UPDATE... ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON. BOYD PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/ UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S. AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING. PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/ DISCUSSION... THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST 15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT PERIOD OF TIME. THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD. WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS. WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS. UNGER AVIATION...06Z TAF DISCUSSION. UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD HANG ON. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
133 PM MDT MON JUL 22 2013 .SYNOPSIS... WE CAN EXPECT A WEAK MONSOONAL PATTERN FOR MOST OF THE WORK WEEK. IN THIS CASE THE PATTERN FAVORS HEAVIER RAINFALL FOR AREAS FROM THE CONTINENTAL DIVIDE WEST...BUT AFTERNOON OR NIGHTTIME THUNDERSTORMS ARE POSSIBLE ANYWHERE IN THE FORECAST AREA EACH AFTERNOON AND EVENING. FOR THE WEEKEND...A BACKDOOR COLD FRONT WILL FRILT WITH OUR AREA WHICH SHOULD SERVE TO DRAW ADDITIONAL TROPICAL MOISTURE INTO THE REGION AND RESULT IN AN INCREASED CHANCE OF SHOWERS AND THUNDERSTORMS. TEMPERATURES DURING UPCOMING WEEK WILL RUN WITH A FEW DEGREES OF NORMAL. && .DISCUSSION... UPPER HIGH IS BEGINNING TO BUILD EAST TO COVER THE CWA FOR THE UPCOMING WEEK. INVERTED TROUGH SLIDING WEST OVER NORTHERN MEXICO MAY PROVIDE A LITTLE EXTRA DYNAMICS/MOISTURE OVER THE SOUTHERN TIER. LAST AVBL HRRR AND 12Z SPC 4KM RUN BOTH SHOW CLUSTER OF STORMS IMPACTING SW PORTIONS OF AREA TONIGHT...SO HAVE RAISED POPS IN THAT AREA, OTHERWISE EXPECT MAINLY A LOW GRADE MONSOONAL PATTERN THROUGH DAYTIME FRIDAY. THERE MAY BE AN UPTICK OF CONVECTION WEDNESDAY WHERE THE ORIENTATION OF THE UPPER HIGH AND THE INVERTED TROUGH ALLOWS A LITTLE EXTRA MOISTURE AND REDUCED STABILITY OVER THE AREA. THE LARGER QUESTION FOR ME IS WHETHER A BACKDOOR FRONT MAKES IT INTO THE AREA FOR THE WEEKEND. WEEKEND RUNS OF THE GFS/ECMWF WERE VERY AGGRESSIVE IN BRINGING THE FRONT INTO THE AREA. LATER RUNS OF THE GFS IN PARTICULAR HAVE BACKED AWAY FROM FROPA OVER THE AREA... HOWEVER CMC 12Z RUN STILL HAS A STRONG PASSAGE. SINCE I HAVE LITTLE TRUST IN GFS HANDLING OF BACKDOORS THIS FAR OUT AND THAT SURFACE TROUGHING WILL ALLOW A CHANNEL OF MOISTURE TO MOVE TOWARD THE FRONT REGARDLESS OF ITS FINAL POSITION...I HAVE BUMPED POPS UP FOR THE WEEKEND AFTERNOONS. IF THE FRONT MAKES IT INTO THE REGION THERE WOULD LIKELY BE AN INCREASE FLOOD RISK AND POSSIBLE SEVERE WEATHER AS WELL. && .AVIATION...VALID 23/00Z-24/00Z. SCATTERED TSRA THRU 06Z OVER THE MOUNTAINS WITH ISOLATED TO WIDELY SCATTERED TSRA IN THE LOWLANDS. STORMS WILL TEND TO DRIFT TOWARDS THE W OR WSW. MOSTLY VFR CONDITIONS ARE EXPECTED WITH THE EXCEPTION OF BRIEF EXCURSIONS INTO MVFR/IFR CONDITIONS IN AND AROUND THUNDERSTORMS. && .FIRE WEATHER... A HIGH PRESSURE RIDGE ALOFT REMAINS ANCHORED OVER THE REGION WITH AMPLE LOW LEVEL MOISTURE IN PLACE AT THE SURFACE. THIS WILL RESULT IN SCATTERED TO WIDELY SCATTERED AFTERNOON AND EVENING THUNDERSTORMS THE NEXT SEVERAL DAYS. CLOSER INSPECTION REVEALS A WEAK UPPER DISTURBANCE TRACKING SLOWLY WESTWARD TO OUR SOUTH ACROSS NORTHERN MEXICO. THIS WILL LIKELY ENHANCE STORM CHANCES NEAR THE INTERNATIONAL BORDER AND AREAS WEST OF THE RIO GRANDE THIS EVENING AND TONIGHT. THIS FEATURE WILL EVENTUALLY EXUDE IT`S INFLUENCE FURTHER NORTH INTO THE REGION MID TO LATE WEEK AS THE RIDGE BEGINS TO WEAKEN. AS A RESULT A GREATER COVERAGE OF WETTING RAINFALL WILL BE POSSIBLE AREA WIDE. THIS TREND WILL CONTINUE INTO THE WEEKEND. WITH LOW LEVEL MOIST AIR IN PLACE MINIMUM RH VALUES WILL CONTINUE TO RUN AROUND 30 PERCENT FOR THE LOWLANDS AND BETWEEN 40 AND 50 PERCENT ACROSS THE HIGHER ELEVATIONS WITH EXCELLENT RECOVERIES OVERNIGHT FOR THE NEXT SEVERAL DAYS. MEANWHILE HAINES INDICES WILL REMAIN LOW TO VERY LOW ACROSS THE REGION. && .PRELIMINARY POINT TEMPS/POPS... EL PASO 73 93 75 93 75 / 30 20 20 20 30 SIERRA BLANCA 69 91 71 92 71 / 30 20 20 30 20 LAS CRUCES 70 93 71 91 70 / 30 20 20 20 40 ALAMOGORDO 70 95 72 95 71 / 30 20 20 30 40 CLOUDCROFT 50 71 52 71 52 / 30 30 20 40 40 TRUTH OR CONSEQUENCES 69 94 71 93 70 / 30 20 20 30 40 SILVER CITY 64 85 65 85 62 / 40 40 30 30 40 DEMING 69 92 70 91 68 / 30 20 20 20 40 LORDSBURG 67 91 69 91 66 / 30 30 30 30 40 WEST EL PASO METRO 74 93 76 92 75 / 30 20 20 20 30 DELL CITY 68 94 69 95 69 / 20 10 20 20 30 FORT HANCOCK 73 94 73 95 73 / 30 20 30 30 30 LOMA LINDA 65 88 66 88 67 / 40 20 20 20 30 FABENS 71 92 73 93 73 / 40 20 30 20 30 SANTA TERESA 71 92 71 91 71 / 40 20 20 20 30 WHITE SANDS HQ 72 94 74 93 74 / 40 20 20 20 30 JORNADA RANGE 66 94 68 93 67 / 40 20 20 20 40 HATCH 70 91 73 89 71 / 30 20 20 20 40 COLUMBUS 69 91 70 90 69 / 40 20 20 20 40 OROGRANDE 69 95 70 95 73 / 30 20 20 20 30 MAYHILL 57 81 59 80 59 / 30 40 20 30 40 MESCALERO 56 85 56 84 56 / 30 30 20 40 40 TIMBERON 57 78 58 78 58 / 30 30 20 30 40 WINSTON 59 84 61 85 60 / 30 30 30 30 40 HILLSBORO 66 89 68 87 67 / 30 30 30 30 40 SPACEPORT 69 94 69 92 68 / 30 20 20 20 30 LAKE ROBERTS 61 85 62 85 60 / 40 50 30 40 50 HURLEY 64 87 65 86 63 / 40 30 30 30 40 CLIFF 65 92 66 92 62 / 30 40 40 30 40 MULE CREEK 58 88 59 88 58 / 30 40 40 40 40 FAYWOOD 65 86 68 87 64 / 30 30 30 30 40 ANIMAS 67 89 68 89 66 / 30 30 30 30 40 HACHITA 68 89 68 89 66 / 30 30 20 20 40 ANTELOPE WELLS 66 86 66 85 66 / 30 30 30 30 40 CLOVERDALE 63 81 64 80 64 / 40 40 30 40 50 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ 02/27
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
408 PM CDT MON JUL 22 2013 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 407 PM CDT MON JUL 22 2013 FORECAST UPDATED FOR THE SEVERE THUNDERSTORM WATCH WHICH COVERS MUCH OF THE FORECAST AREA. WILL DEAL WITH THE FOX CITIES AND LAKESHORE REGION AROUND MID EVENING IF NEEDED. && .SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 220 PM CDT MON JUL 22 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG COLD FRONT MOVING SOUTHEAST OVER WESTERN LAKE SUPERIOR...WESTERN WISCONSIN TO NORTHWEST IOWA. THOUGH UPPER SUPPORT IS LARGELY NORTH OF LAKE SUPERIOR. THERE MAY BE A WEAK IMPULSE OVER NORTHWEST WISCONSIN THAT HELPED CONVECTION FIRE EARLIER THIS AFTERNOON. THOUGH NOT THE 2500 ML CAPES THAT WERE EXPECTED EARLIER...ML CAPES HAVE RISEN INTO THE 1500-2000 J/KG RANGE WHICH WILL BE MORE THAN SUFFICIENT FOR SEVERE STORMS INTO NORTH-CENTRAL WISCONSIN LATER THIS AFTERNOON...PROVIDED THAT THIS PESKY INHIBITION CAN GET WHITTLED AWAY. DESPITE 0-6KM SHEAR OF 35 KTS AND DECENT LOW LEVEL SHEAR...THE FRONT IS STRUGGLING TO PRODUCE GOOD THUNDERSTORMS EVEN WITH DEWPOINTS IN THE UPPER 60S AHEAD OF IT. BUT POTENTIAL WILL REMAIN FOR SEVERE STORMS TO DEVELOP AS INHIBITION IS FURTHER ERODED. STORMS SHOULD BE ARRIVING INTO N-C WISCONSIN BY 21Z AND IRON MOUNTAIN TO WAUSAU BY 00Z. SEVERE WEATHER IS THE MAIN FORECAST CONCERN. TONIGHT...THE COLD FRONT WILL DRIVE SOUTHEAST ACROSS ALL BUT FAR NORTH-CENTRAL WISCONSIN THIS EVENING...AND EXIT AROUND MIDNIGHT OR SHORTLY THEREAFTER. ASSUMING SEVERE STORMS DEVELOP...STORMS SHOULD BE SURFACE BASED INTO THE EVENING WITH ML CAPES AROUND 1.5-2K J/KG AND 0-6KM BULK SHEAR VALUES AROUND 30-35KTS. STORMS SHOULD GROW MORE ELEVATED WITH TIME THIS EVENING WITH CAPES FALLING AS A RESULT. DECENT 0-1KM HELICITY SHOULD BE ABLE TO SUPPORT ROTATING UPDRAFTS THAT WILL KEEP A FEW STORMS ON THE STRONGER SIDE THOUGH...SO THE SEVERE THREAT SHOULD CONTINUE INTO THE MID-EVENING HOURS. AS STORM INTENSITY GRADUALLY DIMINISHES...THE MAIN THREATS WILL TRANSITION TO A DAMAGING WIND THREAT...WHICH SHOULD REACH INTO THE EASTERN SECTIONS OF THE FORECAST AREA LATE IN THE EVENING. BEHIND THE FRONT...PLENTY OF STRATO-CU UPSTREAM OVER MINNESOTA WILL ARRIVE LATE TONIGHT. WILL KEEP PARTLY TO MOSTLY CLOUDY CONDITIONS GOING THROUGH LATE TONIGHT BEFORE MOISTURE THINS OUT. TUESDAY...DRIER AIR WILL BE FILTERING SOUTH ACROSS MUCH OF CENTRAL AND NORTHEAST WISCONSIN DURING THE MORNING...THOUGH LINGERING MOISTURE OVER THE UPPER PENINSULA AND FAR NORTHERN WISCONSIN MAY KEEP SCT-BKN STRATO-CU AROUND A LITTLE LONGER THAN FURTHER SOUTH. NORTHERLY WINDS WILL BE DRIVING IN A COOLER AND LESS HUMID AIRMASS. HIGH TEMPS WILL ONLY REACH FROM THE UPPER 60S TO MID 70S UNDER MOSTLY SUNNY TO PARTLY CLOUDY SKIES. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 220 PM CDT MON JUL 22 2013 UPPER PATTERN DURING PERIOD CHARACTERIZED BY NW UPPER FLOW AND OCNL SHORTWAVE TROFS MOVING THROUGH MEAN TROF POSITION. EACH SHORTWAVE TROF--MID WEEK AND END OF THE WEEK--WILL BRING SCATTERED CONVECTION AND COOLER AIR. STRONGEST OF THE SYSTEMS NEXT WEEKEND WILL BRING CHILLY AIR INTO STATE ON SATURDAY. WHILE UPPER FLOW IS CYCLONIC...SURFACE ANTICYCLONE AND DRY LOW-LEVELS SHOULD MINIMIZE THREAT FOR WIDESPREAD INSTABILITY SHOWERS. TEMP FORECAST THROUGH THE PERIOD GENERALLY A BLEND OF PREVIOUS FORECAST AND BEST PERFORMING 22/12Z MODELS. MIN TEMPS WED AM COULD SLIP TO 40 F IN THE BOGS OF NORTH-CENTRAL WISC. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1237 PM CDT MON JUL 22 2013 A STRONG COLD FRONT WILL BRING A SCT TO BKN LINE OF THUNDERSTORMS ACROSS NORTH-CENTRAL WISCONSIN MID TO LATE AFTERNOON...AND NORTHEAST WISCONSIN EARLY TO MID EVENING. STRONG GUSTY WINDS AND LARGE HAIL ARE POSSIBLE WITH THESE STORMS...BUT THAT WILL BE MORE OF A THREAT OVER NORTH-CENTRAL WISCONSIN THAN FURTHER EAST. BEHIND THE FRONT...PLENTY OF MVFR CIGS OVER NORTH DAKOTA AND MINNESOTA...AND WILL BRING THEM INTO CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT. DRIER AIR WILL EVENTUALLY ARRIVE LATE TONIGHT TO SCOUR OUT THE MVFR CIGS...WHICH WILL LEAVE GOOD FLYING WEATHER FOR TUESDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........TDH SHORT TERM.....MPC LONG TERM......JKL AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
325 PM CDT MON JUL 22 2013 .VERY SHORT TERM...LATE THIS AFTERNOON...TONIGHT AND TUESDAY...FORECAST CONFIDENCE IS MEDIUM. MAIN FORECAST ISSUE CONTINUES TO BE AREAL COVERAGE OF STORMS AND SEVERE RISK WITH PASSAGE OF COLD FRONT LATE THIS AFTERNOON AND THIS EVENING. LATEST RUNS OF THE HRRR AND WRF 4KM WITH LAPS HIGH RESOLUTION MODELS SHOW CONVECTION ASSOCIATED WITH THE FRONT MOVING SOUTHEAST INTO THE NORTHWEST PORTIONS OF THE FORECAST AREA BY 00Z TUESDAY...THEN FALLING APART AS THEY SHIFT FURTHER SOUTHEAST...EXITING THE FAR SOUTHEAST COUNTIES BY 05Z TUESDAY. NAM/GFS/ECMWF/CANADIAN MODELS ALL SHOW QPF WITH THE FRONTAL PASSAGE THIS EVENING...THOUGH 18Z NAM CONTINUES TO BE SOMEWHAT SLOWER THAN THE OTHER MODELS WITH ITS PROGRESSION. SOME QUESTION WITH THE AREAL COVERAGE OF STORMS...AS UPWARD VERTICAL MOTION WITH FRONT OVER THE AREA IS MODEST COMPARED TO THE NORTHEAST AND SOUTHWEST. STILL...ENOUGH UPWARD MOTION WITH FRONT AND PASSING MODEST 500MB VORTICITY MAXIMUM TO BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH THE AREA THIS EVENING...ENDING SOON AFTER MIDNIGHT. MEAN LAYER CAPES OF 1500 TO 2500 J/KG WITH 20 TO 25 KNOTS OF DEEP LAYER SHEAR WILL BRING A RISK FOR LARGE HAIL AND DAMAGING WINDS WITH MAINLY MULTICELL TYPE STRUCTURES. BEST CHANCES WILL REMAIN IN THE SLIGHT RISK AREA FROM SPC...MAINLY NORTHWEST OF A FOND DU LAC TO MADISON TO DARLINGTON LINE. THIS IS WHERE THE SOMEWHAT BETTER DEEP LAYER SHEAR WILL BE LOCATED. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE WITH DECENT PRECIPITABLE WATER VALUES. BRISK NORTH WINDS WITH COLD AIR ADVECTION BEHIND FRONTAL PASSAGE LATER TONIGHT INTO TUESDAY WILL BRING A COOLER AND DRIER AIRMASS INTO THE REGION. THIS IS IN ADVANCE OF HIGH PRESSURE MOVING TOWARD THE REGION FROM THE NORTHWEST. QUIET WEATHER WITH PARTLY CLOUDY SKIES ARE EXPECTED. BREEZY NORTH WINDS WILL KEEP TEMPERATURES SOMEWHAT BELOW SEASONAL NORMALS...ESPECIALLY NEAR THE LAKE. TUESDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH NW FLOW ALOFT WILL PREVAIL WITH HIGH PRESSURE CENTERED OVER WI FOR TUE NT AND WED. A WEAK SHORTWAVE TROUGH MAY BRING SCT-BKN MID LEVEL CLOUDS FOR A TIME WED AFTERNOON AND EVENING. AT MOST...A FEW SPRINKLES TOWARD CENTRAL WI. THE HIGH THEN SHIFTS INTO THE ERN GREAT LAKES FOR WED NT AND THU WHILE A SFC TROUGH MOVES INTO NW WI ON THU. THIS IS AHEAD OF A LARGE UPPER TROUGH THAT IS DIGGING SEWD INTO SRN MANITOBA AND ONTARIO CANADA. WEAK LOW LEVEL WARM ADVECTION WILL DEVELOP LATE WED NT AND THU. 925 MB TEMPS YIELD SFC TEMPS IN THE MID 70S ON WED AND UPPER 70S TO 80F FOR THU. .LONG TERM... FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM THE LARGE POLAR TROUGH WILL TRACK ALONG THE NRN GRTLKS AND CANADIAN BORDER FOR THE WEEKEND. ITS COLD FRONT WILL BRING CHANCES OF SHOWERS AND TSTORMS FOR FRI AND SAT. VERY PLEASANT AND DRY SUMMER WX TO PREVAIL AFTERWARD. && .AVIATION/00Z TAFS/...VFR CONDITIONS ARE EXPECTED THROUGH LATE THIS AFTERNOON ACROSS TAF SITES. SOME DIURNAL CUMULUS CLOUDS WILL LINGER DURING THIS TIME. LAKE BREEZE WILL SHIFT WINDS TO THE SOUTHEAST AT MILWAUKEE AND KENOSHA BY 21Z TO 22Z MONDAY. MADISON SHOULD SEE LIGHT SOUTHWEST WINDS. COLD FRONT WILL SLIDE SOUTHEAST THROUGH TAF SITES BETWEEN 02Z AND 06Z TUESDAY. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH THE FRONT. A FEW MAY CONTAIN LARGE HAIL AND GUSTY WINDS...WITH BETTER CHANCE AT MADISON...LOWER CONFIDENCE AT THE EASTERN SITES. MVFR/IFR VISIBILITIES ARE POSSIBLE WITH ANY STORMS. VFR CONDITIONS ARE THEN EXPECTED AFTER FRONTAL PASSAGE INTO TUESDAY. WINDS WILL SHIFT NORTH NORTHWEST AFTER THE FRONTAL PASSAGE...AND BECOME NORTH NORTHEAST THROUGH TUESDAY. WINDS WILL BECOME GUSTY WITH COOLER AND DRIER AIR MOVING INTO THE REGION DURING THIS TIME. GUSTS INTO THE 20 TO 25 KNOT RANGE ARE POSSIBLE. $$ .MARINE...A TIGHT PRESSURE GRADIENT WILL DEVELOP LATE TONIGHT INTO TUESDAY...AFTER THE COLD FRONTAL PASSAGE. THIS WILL RESULT IN BREEZY NORTH TO NORTHEAST WINDS ACROSS THE NEARSHORE WATERS. FREQUENT GUSTS TO 25 KNOTS ARE POSSIBLE LATE TONIGHT INTO TUESDAY NIGHT. THIS SHOULD CAUSE WAVES TO BECOME HIGH...WITH ONSHORE FLOW AT TIMES. THE WAVES SHOULD REMAIN HIGH INTO WEDNESDAY BEFORE SUBSIDING WITH WEAKER WINDS. THUS...A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR LATE TONIGHT INTO WEDNESDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 PM CDT WEDNESDAY FOR LMZ643>646. && $$ TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD TUESDAY NIGHT THROUGH MONDAY...GEHRING
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 220 PM CDT MON JUL 22 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG COLD FRONT MOVING SOUTHEAST OVER WESTERN LAKE SUPERIOR...WESTERN WISCONSIN TO NORTHWEST IOWA. THOUGH UPPER SUPPORT IS LARGELY NORTH OF LAKE SUPERIOR. THERE MAY BE A WEAK IMPULSE OVER NORTHWEST WISCONSIN THAT HELPED CONVECTION FIRE EARLIER THIS AFTERNOON. THOUGH NOT THE 2500 ML CAPES THAT WERE EXPECTED EARLIER...ML CAPES HAVE RISEN INTO THE 1500-2000 J/KG RANGE WHICH WILL BE MORE THAN SUFFICIENT FOR SEVERE STORMS INTO NORTH-CENTRAL WISCONSIN LATER THIS AFTERNOON...PROVIDED THAT THIS PESKY INHIBITION CAN GET WHITTLED AWAY. DESPITE 0-6KM SHEAR OF 35 KTS AND DECENT LOW LEVEL SHEAR...THE FRONT IS STRUGGLING TO PRODUCE GOOD THUNDERSTORMS EVEN WITH DEWPOINTS IN THE UPPER 60S AHEAD OF IT. BUT POTENTIAL WILL REMAIN FOR SEVERE STORMS TO DEVELOP AS INHIBITION IS FURTHER ERODED. STORMS SHOULD BE ARRIVING INTO N-C WISCONSIN BY 21Z AND IRON MOUNTAIN TO WAUSAU BY 00Z. SEVERE WEATHER IS THE MAIN FORECAST CONCERN. TONIGHT...THE COLD FRONT WILL DRIVE SOUTHEAST ACROSS ALL BUT FAR NORTH-CENTRAL WISCONSIN THIS EVENING...AND EXIT AROUND MIDNIGHT OR SHORTLY THEREAFTER. ASSUMING SEVERE STORMS DEVELOP...STORMS SHOULD BE SURFACE BASED INTO THE EVENING WITH ML CAPES AROUND 1.5-2K J/KG AND 0-6KM BULK SHEAR VALUES AROUND 30-35KTS. STORMS SHOULD GROW MORE ELEVATED WITH TIME THIS EVENING WITH CAPES FALLING AS A RESULT. DECENT 0-1KM HELICITY SHOULD BE ABLE TO SUPPORT ROTATING UPDRAFTS THAT WILL KEEP A FEW STORMS ON THE STRONGER SIDE THOUGH...SO THE SEVERE THREAT SHOULD CONTINUE INTO THE MID-EVENING HOURS. AS STORM INTENSITY GRADUALLY DIMINISHES...THE MAIN THREATS WILL TRANSITION TO A DAMAGING WIND THREAT...WHICH SHOULD REACH INTO THE EASTERN SECTIONS OF THE FORECAST AREA LATE IN THE EVENING. BEHIND THE FRONT...PLENTY OF STRATO-CU UPSTREAM OVER MINNESOTA WILL ARRIVE LATE TONIGHT. WILL KEEP PARTLY TO MOSTLY CLOUDY CONDITIONS GOING THROUGH LATE TONIGHT BEFORE MOISTURE THINS OUT. TUESDAY...DRIER AIR WILL BE FILTERING SOUTH ACROSS MUCH OF CENTRAL AND NORTHEAST WISCONSIN DURING THE MORNING...THOUGH LINGERING MOISTURE OVER THE UPPER PENINSULA AND FAR NORTHERN WISCONSIN MAY KEEP SCT-BKN STRATO-CU AROUND A LITTLE LONGER THAN FURTHER SOUTH. NORTHERLY WINDS WILL BE DRIVING IN A COOLER AND LESS HUMID AIRMASS. HIGH TEMPS WILL ONLY REACH FROM THE UPPER 60S TO MID 70S UNDER MOSTLY SUNNY TO PARTLY CLOUDY SKIES. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 220 PM CDT MON JUL 22 2013 UPPER PATTERN DURING PERIOD CHARACTERIZED BY NW UPPER FLOW AND OCNL SHORTWAVE TROFS MOVING THROUGH MEAN TROF POSITION. EACH SHORTWAVE TROF--MID WEEK AND END OF THE WEEK--WILL BRING SCATTERED CONVECTION AND COOLER AIR. STRONGEST OF THE SYSTEMS NEXT WEEKEND WILL BRING CHILLY AIR INTO STATE ON SATURDAY. WHILE UPPER FLOW IS CYCLONIC...SURFACE ANTICYCLONE AND DRY LOW-LEVELS SHOULD MINIMIZE THREAT FOR WIDESPREAD INSTABILITY SHOWERS. TEMP FORECAST THROUGH THE PERIOD GENERALLY A BLEND OF PREVIOUS FORECAST AND BEST PERFORMING 22/12Z MODELS. MIN TEMPS WED AM COULD SLIP TO 40 F IN THE BOGS OF NORTH-CENTRAL WISC. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1237 PM CDT MON JUL 22 2013 A STRONG COLD FRONT WILL BRING A SCT TO BKN LINE OF THUNDERSTORMS ACROSS NORTH-CENTRAL WISCONSIN MID TO LATE AFTERNOON...AND NORTHEAST WISCONSIN EARLY TO MID EVENING. STRONG GUSTY WINDS AND LARGE HAIL ARE POSSIBLE WITH THESE STORMS...BUT THAT WILL BE MORE OF A THREAT OVER NORTH-CENTRAL WISCONSIN THAN FURTHER EAST. BEHIND THE FRONT...PLENTY OF MVFR CIGS OVER NORTH DAKOTA AND MINNESOTA...AND WILL BRING THEM INTO CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT. DRIER AIR WILL EVENTUALLY ARRIVE LATE TONIGHT TO SCOUR OUT THE MVFR CIGS...WHICH WILL LEAVE GOOD FLYING WEATHER FOR TUESDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......JKL AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1232 PM CDT MON JUL 22 2013 .MESOSCALE DISCUSSION... ISSUED AT 1120 AM CDT MON JUL 22 2013 STILL ASSESSING SEVERE WEATHER POSSIBILITIES FOR LATER TODAY. SHORT WAVE TROUGH CONTINUES TO MOVE THROUGH ONTARIO...NORTH OF INTERNATIONAL BORDER. ASSOCIATED TRAILING COLD FRONT EXTENDS FROM CENTRAL MINNESOTA INTO SIOUX FALLS AREA AS OF 16Z WITH WEAKENING STORM COMPLEX ALONG MISSOURI RIVER. MORNING STRATUS AND FOG ALSO THINING ACROSS THE AREA. DEEP SHEAR IS MUCH MORE FAVORABLE ACROSS NORTHERN WISCONSIN WHILE LOWER LEVEL SHEAR IS HIGHER AS YOU MOVE FURTHER SOUTH-SOUTHWEST. 0-1KM SHEAR IS ALSO STRONGER TO THE NORTH BUT DOES EXTENDED AHEAD AND ALONG THE APPROACHING COLD FRONT. MORNING CLOUD SHIELDS KEEPING HEATING DOWN A BIT BUT DEW POINTS ARE CLIMBING AHEAD OF FRONT SO EXPECT MOST UNSTABLE CAPE VALUES INTO THE 2000 J/KG RANGE BY MID AFTERNOON. LATEST SEVERAL HRRR MESOSCALE MODEL RUNS STILL SUGGEST DEVELOPMENT IN 19-20Z TIME FRAME. ARW/NMM MESOSCALE MODELS ALSO HINT AT THIS BUT SOME UNCERTAINTY ON EXTENT OF COVERAGE AREA. THERE ARE HINTS SUPERCELLS COULD INITIALLY FORM OVER NORTHERN WISCONSIN WITH ONE COMPLEX FORMING WHILE OTHER STORMS FORM ALONG FRONT TO THE SOUTH. MOISTURE TRANSPORT ALSO SHIFTS EAST QUICKLY THROUGH DAY SO THINKING WE WOULD HAVE A NARROW WINDOW OF STORM POSSIBILITIES THAT COULD EVEN SPLIT PARTS OF THE AREA. THIS COULD OCCUR AS SOUTHERN STORMS DIVE INTO HIGHER CAPE VALUES CLOSER AND SOUTH OF I-80. SHEAR VALUES SUGGEST ANY TORNADO RISK REMAINS HIGHEST IN NORTH CENTRAL WISCONSIN WITH INITIAL SUPERCELLS...SOME OF WHICH COULD ALSO PRODUCE HAIL IF CELLS CAN MATERIALIZE CAPE AND GROW THAT STRONG. THIS AREA WOULD LIKELY FORM A MORE LINEAR STRUCTURE BY EARLY EVENING. OTHER STORMS THAT FORM TO THE SOUTH WILL LIKELY BE MORE MULTI-CELLULAR IN NATURE WITH MAINLY WIND THREATS. SO OVERALL CONFIDENCE IS MODEST BUT WITH PROGRESSIVE STORMS...TIME WINDOW LOOKS MORE CERTAIN...FROM 19Z TO 01Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING. LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON. THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500 TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS. CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800 MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON. ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE DAMAGING WINDS. THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE 19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS. OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 AM CDT MON JUL 22 2013 SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES. NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND 80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY. PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90 DURING THE DAY ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1232 PM CDT MON JUL 22 2013 APPROACHING COLD FRONT WILL LIKELY BRING WINDOW OF CONVECTION THAT COULD BRING TEMPORARY MVFR CONDITIONS UNTIL PASSAGE EARLY THIS EVENING. NORMAL VEERING WIND SHIFT EXPECTED WITH FRONT AS WELL. QUESTIONS TO WHAT DEGREE STRATUS FIELD IN BROAD COLD AIR ADVECTION BEHIND FRONT WILL HOLD TOGETHER AND IMPACT AVIATION TONIGHT. VERY CELLULAR NATURE TO CLOUDS SUGGEST MORE DIURNAL BUT FEEL THERE WILL LIKELY BE A WINDOW OF LOWER CEILINGS BEFORE IT DISSIPATES. COULD SEE SOME REFORM LATER TUESDAY AS WELL IN COLDER AIR ALOFT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ MESOSCALE....SHEA SHORT TERM...WETENKAMP LONG TERM....WETENKAMP AVIATION.....SHEA
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1220 PM CDT MON JUL 22 2013 .UPDATE...MAIN FORECAST ISSUE WILL BE AREAL COVERAGE OF STORMS AND SEVERE RISK WITH PASSAGE OF COLD FRONT LATE THIS AFTERNOON AND THIS EVENING. 12Z NAM SLOWER THAN 12Z GFS WITH FRONTAL PASSAGE THROUGH THE AREA THIS EVENING. HRRR AND WRF 4KM WITH LAPS HIGH RESOLUTION MODELS SHOW CONVECTION ASSOCIATED WITH THE FRONT MOVING SOUTHEAST THROUGH THE FORECAST AREA BETWEEN MAINLY 23Z TODAY AND 05Z TUESDAY. THEY DIFFER WITH TRENDS DURING THIS TIME...WITH THE HRRR FAVORING MORE OF THE SOUTHWEST HALF OF THE AREA...AND THE WRF 4KM WITH LAPS FAVORING CONVECTION FROM IOWA MERGING WITH FRONTAL CONVECTION. SOME QUESTION WITH THE AMOUNT OF AREAL COVERAGE OF STORMS...AS UPWARD VERTICAL MOTION WITH FRONT OVER THE AREA IS MODEST COMPARED TO THE NORTHEAST AND SOUTHWEST. STILL...ENOUGH UPWARD MOTION WITH FRONT AND PASSING MODEST 500MB VORTICITY MAXIMUM TO BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH THE AREA. WILL UPDATE FORECAST TO TREND IN THIS MANNER. MEAN LAYER CAPES OF 1500 TO 2500 J/KG WITH 20 TO 25 KNOTS OF DEEP LAYER SHEAR WILL BRING RISK FOR LARGE HAIL AND DAMAGING WINDS. BEST CHANCES WILL BE IN SLIGHT RISK AREA FROM SPC...MAINLY IN THE SOUTH CENTRAL WISCONSIN COUNTIES. THIS IS WHERE THE BETTER DEEP LAYER SHEAR WILL BE LOCATED. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE WITH DECENT PRECIPITABLE WATER VALUES. SHOWERS AND STORMS SHOULD DIMINISH QUICKLY AFTER FRONTAL PASSAGE. && .AVIATION/18Z TAFS/...VFR CONDITIONS ARE EXPECTED THROUGH THIS AFTERNOON ACROSS TAF SITES. DIURNAL CUMULUS CLOUDS WILL LINGER DURING THIS TIME...AND MAY BE MVFR LEVEL AT TIMES EARLY THIS AFTERNOON. LAKE BREEZE WILL SHIFT WINDS TO THE SOUTHEAST AT MILWAUKEE BY 18Z MONDAY...AND KENOSHA BY 21Z MONDAY. IT MAY REACH WAUKESHA BUT LEFT OUT OF TAF THERE DUE TO UNCERTAINTY. MADISON SHOULD SEE LIGHT SOUTHWEST WINDS. COLD FRONT WILL SLIDE SOUTHEAST THROUGH TAF SITES BETWEEN 01Z AND 05Z TUESDAY. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH THE FRONT...SOME OF WHICH MAY CONTAIN LARGE HAIL AND GUSTY WINDS. BEST SHOT WILL BE AT MADISON...LOWER CONFIDENCE AT THE EASTERN SITES. MVFR/IFR VISIBILITIES ARE POSSIBLE WITH ANY STORMS. VFR CONDITIONS ARE THEN EXPECTED AFTER FRONTAL PASSAGE INTO TUESDAY. WINDS WILL SHIFT NORTH NORTHWEST AFTER THE FRONTAL PASSAGE...AND BECOME NORTH NORTHEAST THROUGH TUESDAY. WINDS WILL BECOME GUSTY WITH COOLER AND DRIER AIR MOVING INTO THE REGION DURING THIS TIME. GUSTS INTO THE 20 TO 25 KNOT RANGE ARE POSSIBLE. && .MARINE...A TIGHT PRESSURE GRADIENT WILL DEVELOP LATE TONIGHT INTO TUESDAY...AFTER THE COLD FRONTAL PASSAGE. THIS WILL RESULT IN BREEZY NORTH TO NORTHEAST WINDS ACROSS THE NEARSHORE WATERS. FREQUENT GUSTS TO 25 KNOTS ARE POSSIBLE LATE TONIGHT INTO TUESDAY NIGHT. THIS SHOULD CAUSE WAVES TO BECOME HIGH...WITH ONSHORE FLOW AT TIMES. THE WAVES MAY REMAIN HIGH INTO WEDNESDAY BEFORE SUBSIDING WITH WEAKER WINDS. THUS...A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE TONIGHT INTO WEDNESDAY. && .PREV DISCUSSION... /ISSUED 347 AM CDT MON JUL 22 2013/ SHORT TERM... TODAY AND TONIGHT. FORECAST CONFIDENCE LOW TO MEDIUM. SHORT WAVE TROUGH NEAR LAKE WINNIPEG ON WATER VAPOR LOOPS IS DRIVING ASSOCIATED SURFACE LOW ALONG U.S./CANADIAN BORDER. THUNDERSTORM COMPLEX MOVING INTO NW MN FROM ERN N DAKOTA ALONG TRAILING SURFACE TROUGH IN RELATIVELY WEAK WARM AIR ADVECTION REGIME AHEAD OF THIS WAVE...WITH SWLY 850 MB WINDS OF 15 TO 25 KTS. MOIST SLY SURFACE FLOW AHEAD OF THIS TROUGH POOLING ALONG TROUGH WITH MID-UPPER 60 DEW POINTS. THERMAL RIDGE PUSHES INTO CWA THIS AFTERNOON WITH 850 TEMPS OF 16 TO 18C AND 925 MB TEMPERATURES OF 24C TO 25C...LEADING TO MID-UPPER 80S HIGHS AND A RETURN TO MUGGY CONDITIONS. BEST CHANCES FOR THUNDERSTORMS APPEAR TO BE ACROSS CENTRAL/NORTHERN WISCONSIN CLOSER TO THE SHORT WAVE TROUGH. BEST HEIGHT FALLS STAY WELL NORTH OF THE CWA THROUGH THE DAY...WITH SOME WEAK FALLS DIPPING INTO SRN WI BETWEEN 06Z AND 12Z TUESDAY AS TROUGH DEEPENS OVER EASTERN ONTARIO. 00Z GFS AND ECMWF SHOW HIGHER MID-LEVEL RH AND BETTER OMEGA AS WELL AS 850 MB TEMP ADVECTION STAY NORTH OF CWA. HI-RES MODELS SHOW CONVECTION DEVELOPING ALONG FRONT TO THE NW OF FORECAST AREA DURING PEAK MID-AFTERNOON HEATING. DECENT INSTABILITY OVER ALL OF THE AREA THIS AFTERNOON AND EVENING...WITH SHOWALTER INDICES BETWEEN -2 AND -3C AND SURFACE-BASED CAPE BETWEEN 1500 AND 2000 J/KG BUT BETTER 0-6KM BULK SHEAR IS TO THE NORTH...JUST BRUSHING NWRN CWA WHERE SPC HAS DAY 1 SLIGHT RISK OF SEVERE WITH MAIN THREATS HAIL AND DAMAGING WIND GUSTS. AFTER DRYING OUT A BIT BEHIND YESTERDAY CONVECTION...PWS INCREASE TO 1.5 TO 1.6 INCH...SO POTENTIAL IS CERTAINLY THERE FOR MORE HEAVY RAIN WITH STORMS. WILL TIME PRECIPITATION CHANCES IN WITH MOISTURE CONVERGENCE AND FRONTOGENETIC FORCING AHEAD OF THE FRONT...COVERING THE NW 1/2 OF CWA BY 00Z...AND THE REMAINDER OF THE FORECAST AREA IN THE EARLY EVENING. WILL LIMIT LIKELY POPS TO THE NORTH FOR NOW. NAM SLOWER THAN GFS OR ECMWF WITH 850 MB TROUGH AXIS...WITH COOLER AIR JUST MOVING INTO NW CWA BY 12Z TUESDAY WHILE OTHERS HAVE 850 MB BAROCLINIC ZONE DOWN TO THE WI/IL BORDER BY 12Z. WILL KEEP CHANCE/ SLIGHT CHANCE POPS GOING AFTER 06Z...BUT CLEAR THE NW 1/2 BY 11Z TUESDAY. TUESDAY...FORECAST CONFIDENCE MEDIUM. ANY LINGERING THUNDERSTORMS ALONG THE FRONT SHOULD BE OUT OF SOUTHEAST WI BY 12Z TUE MORNING. DEBATED WHETHER OR NOT TO CARRY ANY POPS INTO 12-15Z TUE...BUT DECIDED NOT TO BASED ON MODELS NOW SHOWING A SLIGHTLY FASTER FRONT. EXPECTING NORTH WINDS TO INCREASE ALONG AND BEHIND THIS COLD FRONT TUESDAY MORNING. HIGHEST WINDS WILL BE NEAR THE LAKE. GUSTS TO 20 MPH WILL BE LIKELY. SKIES ARE EXPECTED TO CLEAR BY TUESDAY AFTERNOON AND SUNSHINE WILL HELP TEMPS TO REBOUND INTO THE UPPER 70S INLAND...AND LOWER/MID 70S NEAR THE SHORELINE. CLEAR SKIES AND RADIATIONAL COOLING WILL LEAD TO LOWS IN THE 50S. NOT EXPECTING FOG SINCE WINDS JUST ABOVE THE GROUND WILL STILL BE IN THE 15-20 KT RANGE. WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE HIGH. SURFACE HIGH PRESSURE WILL SETTLE INTO THE GREAT LAKES REGION WITH WEAK MID AND UPPER LEVEL RIDGING MOVING INTO THE CENTER OF THE COUNTRY. TEMPS WILL BE A LITTLE BELOW NORMAL...WITH HIGHS EXPECTED IN THE UPPER 70S. MODELS ARE MAINTAINING A SMALL THUNDERSTORM CHANCE FOR THU AFTERNOON AND NIGHT...BUT THESE SEEM MINIMAL GIVEN THE DRY AIR IN PLACE OVER SOUTHERN WI AT THIS TIME AND THE VERY WEAK FORCING ASSOCIATED WITH THE MODEL QPF. LONG TERM... FRIDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM TO LOW. A CLOSED UPPER LOW WILL BE SPINNING OVER ONTARIO OVER THE WEEKEND. A LOBE OF VORTICITY WILL ROTATE DOWN THROUGH WI AT SOME POINT AND BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO SOUTHERN WI. TIMING IS UNCERTAIN...BUT SOMETIME IN THE SATURDAY AFTERNOON/NIGHT TIME PERIOD LOOKS REASONABLE. UNFORTUNATELY...THERE IS A SMALL CHANCE FOR THUNDER IN EVERY TIME PERIOD IN THE FORECAST FOR THE WEEKEND GIVEN SUBTLE MODEL DIFFERENCES AND VERY WEAK SHORTWAVES ROTATING AROUND THE UPPER LOW THAT COULD SPAWN AN ISOLATED THUNDERSTORM WITH DIURNAL HEATING. CHANCES ARE VERY LOW OUTSIDE OF THE SAT AFTERNOON/NIGHT TIME. TEMPS WILL GENERALLY BE IN THE 70S THROUGH THE WEEKEND. AVIATION/12Z TAFS/...IFR CIGS/VSBYS HAVE MOVED INTO EASTERN TAF SITES AS LIGHT NORTH TO NORTHEAST WINDS HAVE BROUGHT COOLER AIR OFF THE LAKE INTO THE RAIN-MOISTENED AIR MASS OVER THE REGION. EXPECT THE CIGS AND VSBYS TO LIFT BY MID-MORNING AS GRADIENT WINDS COME AROUND TO THE SOUTH...THEN SOUTHWEST AHEAD OF APPROACHING COLD FRONT. VFR THROUGH THE REST OF THE PERIOD...WITH MVFR IN SCATTERED THUNDERSTORMS AROUND/AFTER 00Z AHEAD OF COLD FRONT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...WOOD TODAY/TONIGHT AND AVIATION/MARINE...REM TUESDAY THROUGH SUNDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1120 AM CDT MON JUL 22 2013 .MESOSCALE DISCUSSION... ISSUED AT 1120 AM CDT MON JUL 22 2013 STILL ASSESSING SEVERE WEATHER POSSIBILITIES FOR LATER TODAY. SHORT WAVE TROUGH CONTINUES TO MOVE THROUGH ONTARIO...NORTH OF INTERNATIONAL BORDER. ASSOCIATED TRAILING COLD FRONT EXTENDS FROM CENTRAL MINNESOTA INTO SIOUX FALLS AREA AS OF 16Z WITH WEAKENING STORM COMPLEX ALONG MISSOURI RIVER. MORNING STRATUS AND FOG ALSO THINING ACROSS THE AREA. DEEP SHEAR IS MUCH MORE FAVORABLE ACROSS NORTHERN WISCONSIN WHILE LOWER LEVEL SHEAR IS HIGHER AS YOU MOVE FURTHER SOUTH-SOUTHWEST. 0-1KM SHEAR IS ALSO STRONGER TO THE NORTH BUT DOES EXTENDED AHEAD AND ALONG THE APPROACHING COLD FRONT. MORNING CLOUD SHIELDS KEEPING HEATING DOWN A BIT BUT DEW POINTS ARE CLIMBING AHEAD OF FRONT SO EXPECT MOST UNSTABLE CAPE VALUES INTO THE 2000 J/KG RANGE BY MID AFTERNOON. LATEST SEVERAL HRRR MESOSCALE MODEL RUNS STILL SUGGEST DEVELOPMENT IN 19-20Z TIME FRAME. ARW/NMM MESOSCALE MODELS ALSO HINT AT THIS BUT SOME UNCERTAINTY ON EXTENT OF COVERAGE AREA. THERE ARE HINTS SUPERCELLS COULD INITIALLY FORM OVER NORTHERN WISCONSIN WITH ONE COMPLEX FORMING WHILE OTHER STORMS FORM ALONG FRONT TO THE SOUTH. MOISTURE TRANSPORT ALSO SHIFTS EAST QUICKLY THROUGH DAY SO THINKING WE WOULD HAVE A NARROW WINDOW OF STORM POSSIBILITIES THAT COULD EVEN SPLIT PARTS OF THE AREA. THIS COULD OCCUR AS SOUTHERN STORMS DIVE INTO HIGHER CAPE VALUES CLOSER AND SOUTH OF I-80. SHEAR VALUES SUGGEST ANY TORNADO RISK REMAINS HIGHEST IN NORTH CENTRAL WISCONSIN WITH INITIAL SUPERCELLS...SOME OF WHICH COULD ALSO PRODUCE HAIL IF CELLS CAN MATERIALIZE CAPE AND GROW THAT STRONG. THIS AREA WOULD LIKELY FORM A MORE LINEAR STRUCTURE BY EARLY EVENING. OTHER STORMS THAT FORM TO THE SOUTH WILL LIKELY BE MORE MULTI-CELLULAR IN NATURE WITH MAINLY WIND THREATS. SO OVERALL CONFIDENCE IS MODEST BUT WITH PROGRESSIVE STORMS...TIME WINDOW LOOKS MORE CERTAIN...FROM 19Z TO 01Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING. LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON. THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500 TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS. CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800 MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON. ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE DAMAGING WINDS. THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE 19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS. OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 AM CDT MON JUL 22 2013 SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES. NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND 80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY. PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90 DURING THE DAY ON SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 623 AM CDT MON JUL 22 2013 SOUTHERLY FLOW AHEAD OF A COLD FRONT IN WESTERN MINNESOTA HAS BEEN BRINGING UP MORE MOISTURE INTO THE REGION AND TAF SITES. THIS MOISTURE HAS MANIFESTED ITSELF AS LIFR TO IFR STRATUS...WITH EVEN SOME FOG RANGING FROM VLIFR TO IFR AT RST. CEILINGS AND VISIBILITIES WILL GRADUALLY RISE THROUGH MORNING DUE TO DAYTIME MIXING...WITH BOTH TAF SITES LIKELY VFR BY 16Z. DURING THE AFTERNOON...THE COLD FRONT IS EXPECTED TO MOVE THROUGH THE TAF SITES. THUNDERSTORMS LOOK LIKELY TO ACCOMPANY THE FRONT...SO IT IS JUST A MATTER OF TIMING. BASED ON A CONSENSUS OF HIGH RESOLUTION MODEL FORECASTS...SPED UP THE TIMING FROM THE 06Z TAFS...IMPACTING RST BETWEEN 19-22Z AND LSE BETWEEN 20-23Z. ITS POSSIBLE THE STORMS COULD EXIT THE TAF SITES A LITTLE SOONER. VISIBILITIES AND CEILING MAY FALL TO MVFR OR PERHAPS EVEN LOWER BRIEFLY. ADDITIONALLY...POTENTIAL EXISTS FOR THE STORMS TO BRING STRONG TO DAMAGING WIND GUSTS AND LARGE HAIL. CONFIDENCE IS TOO LOW TO MENTION ANY SEVERE POTENTIAL DIRECTLY IN THE TAFS AT THIS TIME. VFR CONDITIONS WITH WINDS SHIFTING TO THE NORTHWEST ARE EXPECTED BEHIND THE FRONT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ MESOSCALE....SHEA SHORT TERM...WETENKAMP LONG TERM....WETENKAMP AVIATION.....AJ