Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/03/14


AREA FORECAST DISCUSSION
NWS PUEBLO CO
311 PM MDT MON SEP 1 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 240 PM MDT MON SEP 1 2014 MAIN NEAR/SHORT-TERM METEOROLOGICAL ISSUES ARE TEMPERATURES...LOCALIZED GUSTY WINDS AT TIMES AND LOCALIZED LOW- GRADE POPS. CWFA EXPERIENCING NEAR SEASONAL SEPTEMBER AFTERNOON TEMPERATURES IN COMBINATION WITH GENERALLY SUNNY SKIES...ALTHOUGH SOME VARIABLE CLOUDS NOTED OVER PRIMARILY HIGHER TERRAIN LOCATIONS. IN ADDITION...WIND GUSTS EXCEEDING 30 MPH AT TIMES HAVE BEEN OBSERVED OVER THE MOUNTAINS OF CHAFFEE COUNTY. RECENT RADAR RETURNS INDICATE SHOWERS AND THUNDERSTORMS NEARING FAR NORTHEASTERN COLORADO...WELL NORTH OF OUR CWFA. LATEST COMPUTER SIMULATIONS...REAL-TIME DATA AND FORECAST MODEL SOUNDINGS INDICATE THAT GENERALLY DRY CONDITIONS SHOULD CONTINUE OVER THE MAJORITY OF THE FORECAST DISTRICT FROM LATE THIS AFTERNOON INTO TUESDAY AFTERNOON...ALTHOUGH RECENT HRRR MODEL DATA SUGGESTS THAT SHOWERS AND THUNDERSTORMS MAY THREATEN PORTIONS OF NORTHERN EL PASO AND KIOWA COUNTIES AS WELL AS SECTIONS OF LAS ANIMAS AND BACA COUNTIES FROM LATER THIS AFTERNOON INTO THIS EVENING. FOR TUESDAY...THE HIGHEST PROBABILITY OF ISOLATED SHOWER AND THUNDERSTORM ACTIVITY SHOULD BE NOTED OVER WESTERN HIGHER TERRAIN LOCATIONS...PRIMARILY DURING THE AFTERNOON AND EVENING HOURS. GUSTY...PRIMARILY HIGHER TERRAIN WINDS ARE ALSO ANTICIPATED AT TIMES FROM LATER THIS AFTERNOON INTO TUESDAY WHILE ABOVE SEASONAL EARLY SEPTEMBER AFTERNOON TEMPERATURES ARE PROJECTED TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 240 PM MDT MON SEP 1 2014 ...HOT WITH LOW THUNDERSTORM CHANCES THROUGH EARLY THURSDAY THEN COOLER WITH INCREASING THUNDERSTORM CHANCES... TUESDAY EVENING INTO EARLY THURSDAY...THE AIR MASS OVER THE REGION WILL BE QUITE WARM AND THE THUNDERSTORM CHANCES WILL BE LOW. COULD BE SOME SPOTTY DRY THUNDERSTORMS AROUND TUESDAY EVENING...MAINLY OVER THE MOUNTAINS. THEN...WEDNESDAY AFTERNOON...COULD BE SOME SPOTTY DRY LINE ACTIVITY ACROSS THE FAR SOUTHEAST PLAINS. MODELS HAVE BEEN BACK AND FORTH ON THIS SO CONFIDENCE IS A LITTLE LOW BUT THE POSSIBILITY REMAINS ALIVE. ON THURSDAY...THINGS START TO TRANSITION TO A COOLER...WETTER PATTERN. MODELS HAVE BEEN PRETTY CONSISTENT ON THIS SO CONFIDENCE IS INCREASING. IT STARTS WITH THE ARRIVAL OF A COLD FRONT THROUGH THE EASTERN PLAINS THURSDAY AFTERNOON. THE FRONT PUSHES INTO THE REGION AS THE RESULT OF AN UPPER DISTURBANCE MOVING THROUGH THE NORTHERN ROCKIES AND PLAINS. AS THE FRONT MOVES IN...MOIST UPSLOPE WINDS BEHIND THE FRONT GRADUALLY FIRE THUNDERSTORMS OVER AND NEAR THE MOUNTAINS IN THE AFTERNOON...SOME OF WHICH WORK EAST ACROSS THE PLAINS BY LATE IN THE DAY. WITH ADDED MOISTURE IN THE AIR AND UPSLOPE WINDS...THE THREAT FOR STRONG STORMS WILL INCREASE THIS DAY. FRIDAY THROUGH MONDAY...WE COULD BE DEALING WITH SOME RICH SUBTROPICAL MOISTURE AT TIMES...JUST DEPENDING ON HOW THINGS TRACK OVER THE NEXT FEW DAYS. RIGHT NOW...INDICATIONS ARE THAT FRIDAY AND SATURDAY COULD BOTH BE PRETTY WET OVER THE REGION WITH CONCERNS OF FLASH FLOODING. SUNDAY AND MONDAY STILL LOOK PRETTY WET FOR THE MOUNTAINS...BUT THE PLAINS LOOK MORE STABLE WITH LESS ACTIVITY. ALL OF THIS IS STILL SEVERAL DAYS AWAY AND HIGHLY SUBJECT TO CHANGE...HOWEVER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 240 PM MDT MON SEP 1 2014 VFR CONDITIONS ARE ANTICIPATED AT THE KALS...KCOS AND KPUB TAF SITES THROUGH TUESDAY AFTERNOON. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...77 LONG TERM...LW AVIATION...LW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
716 PM EDT TUE SEP 2 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION TONIGHT AND WILL BE ACCOMPANIED BY SCATTERED SHOWERS AND THUNDERSTORMS. BEHIND THE FRONT DRIER AND MUCH LESS HUMID AIR OVERSPREADS THE AREA WEDNESDAY AND THURSDAY. HUMIDITY WILL ONCE AGAIN INCREASE BY THE END OF THE WEEK AS THE NEXT COLD FRONT BRINGS THE RISK FOR MORE SCATTERED SHOWERS/THUNDERSTORMS FRIDAY NIGHT AND SATURDAY. MORE AUTUMN-LIKE WEATHER FOLLOWS SUNDAY AND INTO AT LEAST EARLY NEXT WEEK WITH COOLER AND LESS HUMID CONDITIONS. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 7 PM UPDATE... NOT MUCH CHANGE TO PREVIOUS FORECAST. LATEST MESOSCALE MODELS INCLUDING THE RAP13 AND HRRR SUGGEST UPSTREAM CONVECTION OVER WESTERN-CENTRAL NY INTO PA WILL ENTER WESTERN NEW ENGLAND BETWEEN 9 PM AND 11 PM. A FEW STRONG STORMS ARE POSSIBLE ACROSS THIS AREA WITH GUSTY WINDS/HAIL AND HEAVY DOWNPOURS. THE LINE OF STORMS IS THEN EXPECTED TO WEAKEN LATER THIS EVENING AND OVERNIGHT AS THE ACTIVITY MOVES EAST OF THE CT RVR. PREVIOUS FORECAST CAPTURES THESE DETAILS NICELY SO NO MAJOR CHANGES WITH THIS UPDATE. EARLIER DISCUSSION BELOW. ================================================================== TONIGHT... STRONG COLD FRONT WILL MOVE ACROSS THE NORTHEAST OVERNIGHT. THIS FRONT IS EXPECTED TO MOVE INTO THE WESTERN ZONES AROUND 02-04Z AND OFFSHORE BETWEEN 10-12Z. ANTICIPATE CONVECTION WILL BE ONGOING AS IT APPROACHES THE REGION PER THE AMOUNT OF SURFACE HEATING AND DYNAMICS OUT AHEAD OF IT IN WESTERN CWA`S. BY THE TIME IT APPROACHES THE REGION A GOOD AMOUNT OF INSTABILITY WILL BE LOSS SO WE MAY SEE DYING CONVECTION. HOWEVER SOME MODELS...ESP THE HIGH-RES GUIDANCE SHOWS ABOUT 500 J/KG OF CAPE LINGERING BY THE TIME THE FRONT APPROACHES. ON TOP OF THE POSSIBLE INSTABILITY...850MB LLJ DOES INCREASE AS THE FRONT APPROACHES AND SHEAR VALUES INCREASE AS WELL. IN FACT...GUIDANCE SHOWS THAT 0-6KM SHEAR INCREASES TO 25KTS...BUT IT IS THE 0-1 KM SHEAR THAT INCREASES TO 30-40KTS. LASTLY K-INDEX PLUME MOVES OVER THE REGION DURING THIS TIMEFRAME GIVING THE REGION THE MOISTURE IT NEEDS FOR THUNDERSTORMS TO CONTINUE. THEREFORE BELIEVE THAT ALL THE INGREDIENT MENTIONED ABOVE MAY ALLOW FOR A FEW STRONG TO PERHAPS A SEVERE STORM AS THE FRONT MOVES THE REGION. KEEP IN MIND THAT THIS IS AN OVERNIGHT EVENT WHICH IS NOT IN THE NORTHEAST FAVOR PER CLIMO...BUT CONDITIONS DO SHOW THAT A FEW STRONG STORMS ARE POSSIBLE. LASTLY...EVEN THOUGH THE REGION DID SEE SOME ACTION TODAY...THE ATMOSPHERE DID BOUNCE BACK VERY WELL AFTER THE STORMS PASSED. AS THE FRONT MOVES THROUGH THE K-INDEX VALUE AS WELL AS THE INSTABILITY DO DROP AFTER 06Z SO THAT THE CHANCE FOR ANY CONVECTION TO OCCUR DISSIPATES SIGNIFICANTLY. IN FACT...THE SHOWERS AND THUNDERSTORMS FROM THE FRONT WILL FRAGMENT AND BECOME VERY ISO IN NATURE BY THIS TIME FRAME AND MAY EVEN STRUGGLE TO REACH THE EAST COAST. WITH THE AMOUNT OF MOISTURE IN THE ATMOSPHERE BELIEVE THAT A FEW SHOWERS WILL REACH SO CONTINUED THE SLIGHT CHANCE POP FOR NOW. OVERNIGHT TEMPS WILL STRUGGLE TO DROP AS CLOUD COVER WILL KEEP TEMPS FROM RADIATING OUT OVERNIGHT AND DEWPOINTS WILL REMAIN IN THE 70S UNTIL FRONTAL PASSAGE. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... TOMORROW AND TOMORROW NIGHT... SURFACE FRONT WILL MOVE OFFSHORE BY EARLY TOMORROW MORNING AS UPPER LEVEL TROUGH WILL PUSH THROUGH AS WELL. 850 MB RIDGE WILL BEGIN TO SET UP OVER THE REGION ALLOWING FOR DRY AIR TO MOVE INTO THE AREA. THIS WILL KEEP THE WEATHER DRY FOR BOTH TOMORROW AND TOMORROW NIGHT. 850 MB TEMPS DROP DOWN TO -14C AND WITH MIXING UP TO 850MB WILL ALLOW FOR TEMPS TO REACH INTO THE MID TO UPPER 80S. DIFFERENCE WILL BE THE HUMIDITY AS DRY AIR WILL MIX DOWN DROPPING DEWS DOWN INTO THE UPPER 50S. WINDS WILL BE GUSTY REACHING ABOUT 20 MPH. OVERNIGHT...WITH CLEAR SKIES AND WINDS BECOME LIGHT AND VARIABLE...ANTICIPATE RADIATIONAL COOLING. LOWS WILL DROP INTO THE MID TO LOW 50S. A FEW SITES COULD EVEN DROP INTO THE UPPER 40S ACROSS CT VALLEY. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HIGHLIGHTS: * DRY THU/FRI WITH WARMER THAN NORMAL AFTERNOON TEMPS * MORE HUMID SAT WITH SCATTERED STORMS POSSIBLE * TREND TOWARD COOLER/LESS HUMID WEATHER SUN INTO EARLY NEXT WEEK THURSDAY AND FRIDAY... DRY/QUIET WEATHER CONTINUES THU WITH HIGH PRES AND A DRY/STABLE AIRMASS OVER THE REGION. IT WILL BE WARM WITH HIGHS OF 80- 85...COOLER ALONG THE COAST WITH AFTERNOON SEABREEZES...HOWEVER DEW PTS REMAINING IN THE 50S WILL PROVIDE COMFORTABLE HUMIDITY LEVELS. BY FRIDAY THE SUBTROPICAL RIDGE ALONG THE EAST COAST BRIEFLY BUILDS NORTHWARD INTO SOUTHERN NEW ENGLAND AHEAD OF THE NEXT NORTHERN STREAM TROUGH. THIS WILL RESULT IN WARMER TEMPS WITH HIGHS WELL INTO THE 80S COMBINED WITH MORE HUMID CONDITIONS AS DEW PTS CLIMB FROM THE 50S INTO THE 60S. THUS A WARM AND HUMID DAY FRIDAY. ALL MODEL GUIDANCE INCLUDING THE 12Z GEFS AND NEW 12Z ECMWF SUGGEST JET DYNAMICS/BEST SHEAR/INSTABILITY AND CONVERGENCE ASSOCIATED WITH COLD FRONT HOLD OFF UNTIL SAT. THUS SLIGHT CHANCE POPS CONFINED TO WESTERN NEW ENGLAND LATE FRI FROM A MODEL BLEND SEEMS REASONABLE. HENCE MOST OF THE AREA ESPECIALLY RI AND EASTERN MA MAY REMAIN DRY FRI. SATURDAY... ALL DETERMINISTIC AND PROBABILISTIC /12Z GEFS AND 12Z ECENS/ GUIDANCE SUGGEST COLD FRONT WILL MOVE SLOWLY INTO THE REGION SAT. TEMPS ARE PROJECTED TO BE IN THE 80S SAT ALONG WITH DEW PTS IN THE 60S TO NEAR 70 SO THIS SHOULD YIELD AT LEAST MARGINAL INSTABILITY. THE 12Z GEFS SUGGEST A 30-40% PROBABILITY OF UP TO 1200 J/KG OF CAPE. THIS COMBINED WITH MODEST JET DYNAMICS/SHEAR AND FRONTAL CONVERGENCE EXPECTING A RISK FOR SCATTERED THUNDERSTORMS ALONG WITH A THREAT FOR HEAVY RAIN AS PWATS CLIMB ABOVE NORMAL. COULD BE A FEW STRONG STORMS GIVEN THE PARAMETERS MENTIONED ABOVE. SUNDAY... LIKELY OUR TRANSITION DAY AS BOTH ENSEMBLES /12Z ECENS AND GEFS/ SUGGEST FRONT MAY BE SLOW TO CLEAR THE COAST SUN MORNING. THUS SHOWERS MAY LINGER EARLY SUNDAY ESPECIALLY SOUTH COAST WITH A TREND TOWARD DRIER WEATHER AS THE DAY PROGRESSES FROM NW TO SE. MONDAY AND TUESDAY... SHOULD BE DRIER...COOLER AND LESS HUMID AS FRONT MOVES OFFSHORE. HOWEVER SOME OF THE GUIDANCE SHOWS UNCERTAINTY HOW FAR OFFSHORE THIS BOUNDARY GETS. THUS CLOUDS AND POSSIBLE UNSETTLED WEATHER MAY LURK JUST OFFSHORE. WILL KEEP THE FORECAST DRY FOR NOW. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE IN TRENDS. 7 PM UPDATE...NO MAJOR CHANGES FROM 18Z TAFS. SHOWERS AND T-STORMS OVER MA CONTINUE TO ERODE. NEXT ROUND OF T-STORMS OVER WESTERN- CENTRAL NY AND PA ARRIVES IN WESTERN NEW ENGLAND 01Z-03Z THEN WEAKENS AS IT ENTERS EASTERN NEW ENGLAND. FOG AT NANTUCKET WILL PERSIST AND THEN BEGIN TO IMPROVE AROUND 06Z AND ESPECIALLY 09Z- 12Z WHEN FRONTAL PASSAGE OCCURS. EARLIER DISCUSSION BELOW. ============================================================== TONIGHT...A LULL IN ACTIVITY AFTER 00Z. BEFORE ANOTHER ROUND OF SHOWERS WITH ISO THUNDER MOVES THROUGH AFTER 03/04Z. THIS CONVECTION IS ASSOCIATED WITH AN APPROACHING COLD FRONT WHICH WILL PASS THROUGH THE REGION OVERNIGHT. EXPECT CONVECTION TO WEAKEN AS IT MOVES THROUGH WITH BRIEF LOWERING IN CIG HEIGHTS. PATCHY FOG IS EXPECT AHEAD OF THE FRONT AND SHOULD DISSIPATE AS IT PASSES THROUGH. WED INTO WED NIGHT...VFR. PATCHY FOG IN CT VALLEY WED NIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. MAY BE A SHOWER OR THUNDERSHOWER IN THE AFTERNOON. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...THURSDAY THROUGH SATURDAY... THU AND FRIDAY...HIGH CONFIDENCE. MAINLY VFR CONDITIONS OTHER THAN LATE NIGHT/EARLY MORNING PATCHY GROUND FOG IN THE TYPICALLY PRONE LOCATIONS. FRIDAY NIGHT AND SATURDAY...MODERATE CONFIDENCE. A PERIOD OF MVFR- IFR CONDITIONS EXPECTED IN LOW CLOUDS/FOG PATCHES AND SCT SHOWERS/THUNDERSTORMS. TIMING HIGHLY UNCERTAIN AT THIS POINT. SUNDAY...ANY MVFR ALONG SOUTH COAST SHOULD TREND TOWARD VFR WITH POTENTIAL SHOWERS MOVING OFFSHORE. OTHERWISE VFR PREVAILS ELSEWHERE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH THE PERIOD WEDNESDAY NIGHT. TONIGHT... SW FLOW BEGINS TONIGHT BEFORE A COLD FRONT PASSES OVER THE WATERS OVERNIGHT. EXPECT A FEW GUSTS TO AROUND 20 KT ARE POSSIBLE AS THE WINDS SHIFT TO THE W-NW. A FEW SHOWERS AND THUNDERSTORMS MAY MOVE OVER THE SOUTHERN WATERS BY MIDNIGHT LASTING TIL ABOUT 3AM. SEAS MAY APPROACH 5 FT ON THE SOUTH OCEAN WATERS BUT HAVE LOW CONFIDENCE AND HELD OFF ON ISSUING A SCA. OTHERWISE...SOME FOG MAY LEAD TO VSBY REDUCTIONS TONIGHT BEFORE THE FRONT PASSES. WED INTO WED NIGHT...QUIET BOATING WEATHER. A FEW GUSTS NEAR 15KTS POSSIBLE DURING THE DAY. OUTLOOK...THURSDAY THROUGH SATURDAY... MODERATE CONFIDENCE THROUGH THIS PERIOD. THURSDAY...HIGH CONFIDENCE. WEAK PRESSURE GRADIENT YIELDS LIGHT WINDS AND SEAS ALONG WITH GOOD VISIBILITIES SHOULD MAKE FOR NICE BOATING WEATHER. AFTERNOON SEABREEZES EXPECTED. FRIDAY...MODERATE TO HIGH CONFIDENCE. NEAR SHORE SOUTHWEST WIND GUSTS OF 20 TO 25 KNOTS MAY DEVELOP IN THE AFTERNOON WITH GOOD MIXING OVER THE LAND. SW WIND WAVES DEVELOP ESPECIALLY NEAR SHORE. DRY WEATHER WILL PREVAIL WITH A CHANCE OF SHOWERS/T-STORMS INCREASING AFTER SUNSET. FRIDAY NIGHT AND SATURDAY...MODERATE CONFIDENCE. AREAS OF FOG MAY AFFECT THE SOUTHERN WATERS. SOUTHWEST WIND GUSTS AROUND 20 KNOTS ARE EXPECTED AHEAD OF AN APPROACHING COLD FRONT. THERE WILL BE THE RISK OF SCT SHOWERS AND THUNDERSTORMS DURING THE DAY SATURDAY WITH A FEW STRONG STORMS POSSIBLE...WIND AND HEAVY RAIN. SUNDAY...FRONT BEGINS TO MOVE OFFSHORE SLOWLY BUT SHOWERS MAY LINGER ESPECIALLY IN THE MORNING. && .CLIMATE... BOSTON LOGAN AIRPORT REACHED 93 DEGREES TODAY. THIS IS THE WARMEST TEMPERATURE IN BOSTON SO FAR THIS SUMMER. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/DUNTEN NEAR TERM...NOCERA/DUNTEN SHORT TERM...DUNTEN LONG TERM...NOCERA AVIATION...NOCERA/DUNTEN MARINE...NOCERA/DUNTEN CLIMATE...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1034 AM EDT MON SEP 1 2014 .SYNOPSIS... HIGH PRESSURE WILL BRING A RETURN TO SOME SUNSHINE AND VERY WARM TEMPERATURES TODAY. IT WILL REMAIN HUMID...AS TEMPERATURES COULD TURN EVEN HOTTER ON TUESDAY. A COLD FRONT WILL APPROACH THE REGION LATE TUESDAY INTO TUESDAY EVENING BRINGING NUMEROUS SHOWERS AND THUNDERSTORMS...AND SLIGHTLY COOLER AND NOTICEABLY DRIER AIR WILL FOLLOW ON WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1034 AM EDT...A WEAK SFC RIDGE WILL BUILD IN OVER NY AND NEW ENGLAND TODAY...AS THE WATER VAPOR LOOP SHOWS SOME DRYING ALOFT WITH THE PASSAGE OF A MID-LEVEL SHORT WAVE OVER NRN NEW ENGLAND. MID LEVEL HEIGHTS ARE BUILDING UPSTREAM OVER SE CANADA...W-CNTRL NY AND PA THIS MORNING. THE LATEST 3-KM HRRR SHOWS VERY LITTLE CONVECTIVE ACTIVITY THIS PM WITH A MID LEVEL CAP SETTING UP...AND A LACK OF A GOOD FOCUSING MECHANISM. THE BEST CHC FOR AN ISOLD-SCT POP UP SHOWER OR THUNDERSTORM IS SOUTH OF THE CAPITAL REGION. SBCAPE VALUES WILL BE IN THE 1000-1500 J/KG RANGE THERE...AND THE DIFFERENTIAL HEATING BTWN THE MTNS/VALLEYS COULD ALLOW FOR SOME POP-UP ACTIVITY. ISOLD- SCT SHOWERS WITH AN ISOLD THUNDERSTORM WERE ONLY KEPT IN THE FCST SOUTH OF THE CAPITAL REGION FOR MAINLY THE MID TO LATE PM. HIGHS TODAY WILL GENERALLY BE IN THE LOWER TO M80S...WITH A FEW U80S IN THE MID HUDSON VALLEY/NW CT. EXPECT U70S TO L80S OVER THE MTNS. IT WILL REMAIN VERY HUMIDITY WITH SFC DEWPTS IN THE M60S TO L70S. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... ANY LEFTOVER CONVECTION WILL END SHORTLY AFTER SUNSET...LEAVING US WITH A RAINFREE BUT MUGGY OVERNIGHT. MORE PATCHES OR EVEN AREAS OF FOG WILL FORM AFTER MIDNIGHT. LOWS WILL BE IN THE 60S...CLOSE TO 70 IN THE TRI-CITY REGION. TUESDAY...A SOUTH TO SOUTHWEST WIND WILL INCREASE A LITTLE AHEAD OF COLD FRONT APPROACHING FROM THE NORTHWEST. H850 TEMPERATURES LOOK TO RAMP UP TO ABOUT +18C. WITH ANY MORNING AND MIDDAY SUNSHINE...TEMPERATURES LOOK TO GO EVEN A LITTLE HIGHER THAN TODAY...80S...TO NEAR 90 JUST SOUTH OF THE CAPITAL REGION. THE ONLY EXCEPTION WILL BE THE ADIRONDACK PARK WHERE MORE CLOUDS AND SHOWERS/THUNDERSTORMS...ASSOCIATED WITH AN ADVANCING COLD FRONT...WILL KEEP TEMPERATURES HELD TO THE UPPER 70S. APPARENT TEMPERATURES ON TUESDAY AFTERNOON ARE FORECASTED TO REACH THE UPPER 90S IN PORTIONS OF THE MID HUDSON VALLEY...GENERALLY LOWER TO MID MOST OTHER VALLEY AREAS...80S OVER THE HIGHER TERRAIN. THE AFOREMENTIONED COLD FRONT (AND PERHAPS A PRE-FRONTAL TROUGH) WILL ADVANCE OVER MOST OUR REGION DURING THE AFTERNOON AND EARLY EVENING HOURS. THIS FRONT PRODUCED QUITE OF BIT OF THUNDERSTORM WIND DAMAGE AND SOME LARGE HAIL IN THE MID WEST. SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP ALONG OR A LITTLE AHEAD OF THESE FEATURES. IT DOES APPEAR THE BEST FORCING WILL ACTUALLY LIFT INTO CANADA AS THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET MOVES THAT WAY. NEVERTHELESS THERE SHOULD BE PLENTY OF INSTABILITY...LOW LEVEL CONVERGENCE (ASSOCIATED WITH THE FRONT)...AND MOISTURE...TO GENERATE SHOWERS AND STORMS. AN ORGANIZED LINE COULD EVEN FORM. FOR NOW...SINCE WE ARE NOT OFFICIALLY OUTLOOKED BY SPC...WE WILL ONLY MENTION POSSIBLE HEAVY RAINFALL WITH THE THUNDERSTORMS ON TUESDAY SINCE PWAT VALUES WILL ONCE AGAIN INCREASE TO 2 INCHES OR BETTER...EXCEEDING 70% OF NORMAL AMOUNTS FOR EARLY SEPTEMBER. SHOWERS AND THUNDERSTORMS COULD LINGER INTO TUESDAY EVENING...BUT AT THIS POINT...THE FRONT LOOKS TO MOVE FAIRLY QUICKLY EAST AND BE REPLACED BY SOMEWHAT DRIER AND COOLER AIR. THE THUNDERSTORM THREAT LOOKS TO WANE BY MIDNIGHT. TEMPERATURES OVERNIGHT TUESDAY LOOK TO FALL BACK INTO THE MID 50S TO THE NORTHWEST OF ALBANY...60-65 FURTHER SOUTH. AN AIRMASS ORIGINATING FROM SOUTHERN CANADA WILL BRING A GUSTY NORTHWEST BREEZE WHICH WILL DROP DEWPOINTS BACK INTO THE 50S ON WEDNESDAY. HIGH TEMPERATURES WILL ACTUALLY STILL BE SLIGHTLY ABOVE NORMAL...RANGING FROM THE MID 70S TO MID 80S...LOCALLY AROUND 80 IN ALBANY. HOWEVER...WITH THE BREEZE AND LOWER HUMIDITY...IT WILL BE MORE PLEASANT OUTDOORS. A MAINLY CLEAR NIGHT ON WEDNESDAY AND LIGHT WIND WILL ALLOW TEMPERATURES SETTLE BACK INTO THE 50S ACROSS MUCH OF OUR AREA...EXCEPT MID OR UPPER 40S OVER PORTIONS OF THE ADIRONDACKS AND SOUTHERN GREENS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... THE LONG TERM PERIOD STARTS OUT WITH HIGH PRESSURE IN CONTROL AND INCREASINGLY WARM TEMPS AS A SOUTHWESTERLY FLOW TAKES HOLD ON THE WESTERN SIDE OF A LARGE HIGH PRESSURE THAT WILL BE SLIDING OFF THE COAST. MAINLY DRY WEATHER IS FORECAST WITH ONLY A SLIGHT CHANCE OF SHOWERS/TSTMS LATER FRIDAY AFTN AS A COLD APPROACHES FROM THE GREAT LAKES. HIGHS THURSDAY WILL BE IN THE UPPER 70S TO MID 80S...AND A COUPLE OF DEGREES WARMER ON FRIDAY. LOWS THURSDAY NIGHT IN THE MID 50S TO LOWER 60S. THE COLD FRONT WILL MOVE INTO THE REGION AT THE START OF THE WEEKEND ALONG WITH THE THREAT OF SHOWERS/TSTMS. SOME MODEL DISAGREEMENT AS TO HOW FAST THIS FRONT WILL MOVE THROUGH. THE CANADIAN MODEL IS THE FASTEST OF ALL AND ACTUALLY HAS THE FRONT SOUTH AND EAST OF THE REGION BY SATURDAY MORNING WITH PCPN ENDING. ECMWF LINGERS THE FRONT OVER THE REGION THROUGH THE WEEKEND WITH A CHANCE OF SHOWERS/TSTMS THROUGH MUCH OF SUNDAY. THE GFS IS IN BETWEEN WITH THE FRONT SOUTH AND EAST OF THE REGION BY SATURDAY AFTERNOON WITH THE THREAT OF SHOWERS CONFINED TO FRIDAY NIGHT AND EARLY SATURDAY. CANADIAN SEEMS TOO FAST...SO TAKEN A COMPROMISE BETWEEN THE GFS AND ECMWF WITH A CHANCE OF SHOWERS FORECAST FRIDAY NIGHT THROUGH SATURDAY NIGHT...THEN CLEARING AND COOLER ON SUNDAY AS A LARGE CANADIAN HIGH PRESSURE SYSTEM BUILDS INTO THE REGION. LOWS FRIDAY NIGHT WILL BE IN THE UPPER 50S TO MID 60S. HIGHS SATURDAY IN THE 70S TO LOWER 80S. LOWS SATURDAY NIGHT IN THE UPPER 40S AND 50S. HIGHS SUNDAY IN THE MID 60S TO MID 70S. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... MVFR TO OCCASIONAL IFR CONDITIONS DUE TO FOG/STRATUS WILL PERSIST AT THE KGFL/KALB/KPSF TAF SITES TO 12Z-14Z THIS MORNING...WITH VFR TO OCCASIONALLY MVFR VSBYS AT KPOU THROUGH 14Z. AFTER AROUND 13Z...VFR CONDITIONS WILL RETURN TO ALL THE TAF SITES. LINGERING LOW LEVEL MOISTURE AND SOME WEAK INSTABILITY COULD RESULT IN ISOLATED SHOWERS/TSTMS THIS AFTN...SO HAVE INCLUDED VCSH IN THE TAF FORECASTS FROM AROUND 19Z THRU 00Z TUESDAY. FOR TONIGHT...EXPECT MAINLY CLEAR SKIES AND LIGHT WINDS...SO FOG FORMATION IS LIKELY AGAIN. HAVE FORECAST CONDITIONS TO LOWER TO MVFR/IFR AT ALL THE TAF SITES AROUND AND AFTER MIDNIGHT. WINDS WILL BE CALM OR LIGHT AND VARIABLE EARLY THIS MORNING...THEN BECOME SOUTH OR SOUTHWEST AT 8 KTS OR LESS DURING THE REST OF THE DAY. THE WINDS WILL BECOME LIGHT AND VARIABLE OR CALM AGAIN TONIGHT. OUTLOOK... TUESDAY: HIGH OPERATIONAL IMPACT. LIKELY PM SHRA...TSRA. TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHC SHRA...TSRA. WEDNESDAY THROUGH FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... TODAY WILL FEATURE PATCHES OF FOG TO START THE DAY. A STRAY SHOWER OR THUNDERSTORM IS POSSIBLE THIS AFTERNOON...MAINLY SOUTH OF ALBANY...BUT THAT WILL BE EXCEPTION RATHER THAN THE RULE. WITH ONLY A LIGHT WIND...MAINLY OUT OF THE SOUTHWEST...RH VALUES WILL REMAIN ELEVATED TODAY...ONLY DROPPING TO THE 55-65 PERCENT RANGE. IT WILL BE VERY WARM WITH A GOOD DEAL OF SUNSHINE (ONCE THE FOG BURNS OFF). LOOK FOR A FULL RECOVERY TONIGHT WITH MORE FOG AND RH VALUES NEAR 100 PERCENT. TUESDAY WILL BE VERY WARM ONCE MORE. SOME SUNSHINE SHOULD BURN THE FOG AWAY PERHAPS A LITTLE QUICKER THAN TODAY. BY AFTERNOON THOUGH...A COLD FRONT WILL APPROACH...LIKELY TRIGGERING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS...SOME OF WHICH COULD CONTAIN TORRENTIAL RAINFALL. DRIER AND SLIGHTLY COOLER AIR WILL FILTER IN BEHIND THE COLD FRONT LATE TUESDAY NIGHT AND HOLD FOR THE REMAINDER OF THE WEEK. && .HYDROLOGY... THERE WERE POCKETS OF ONE INCH OR MORE OF RAINFALL...MAINLY NORTH AND SOUTH OF THE CAPITAL REGION ON SUNDAY. MOST AREAS HOWEVER RECEIVED WELL UNDER AN INCH OF RAINFALL. THERE WAS LITTLE IF ANY IMPACT ON MAIN STEM RIVERS SINCE WE HAD BEEN DRY BEFORE THIS RAIN MOVED IN. ANY SHOWERS OR THUNDERSTORMS TODAY WILL BE WIDELY SCATTERED AND SHOULD HAVE NO IMPACT ON OUR WATERSHED. TUESDAY COULD BE A DIFFERENT STORY. WE EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS AFTERNOON AND EVENING. AVERAGE BASIN RAINFALL LOOKS TO BE MAINLY UNDER AN INCH SO ONCE AGAIN WE DO NOT EXPECT MANY IF ANY RISES ON THE RIVERS. HOWEVER...RAINFALL COULD BE LOCALLY HEAVY PRODUCING THE USUAL PONDING PROBLEMS. DRIER WEATHER RETURNS BY WEDNESDAY...LASTING THROUGH THE REMAINDER OF THE WORKWEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...HWJIV/WASULA NEAR TERM...WASULA SHORT TERM...HWJIV LONG TERM...GJM AVIATION...GJM/WASULA FIRE WEATHER...HWJIV HYDROLOGY...HWJIV
AREA FORECAST DISCUSSION
NWS MIAMI FL
130 PM EDT MON SEP 1 2014 .AVIATION... MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST. SEA BREEZE CIRCULATION APPEARS TO HAVE FINALLY SET UP ALONG THE EAST COAST WITH MOST SHRA ACTIVITY DIMINISHING. STILL COULD HAVE ONE OR TWO SHRA DEVELOP UNTIL AROUND 20Z BUT TOO ISOLATED TO PLACE MENTION IN THE TAF AT THIS TIME. LATEST SHORT TERM HIGH RESOLUTION GUIDANCE INDICATES CONVECTION WILL BEGIN TO FIRE ALONG THE SOUTHWEST COAST BTWN 18-19Z SO KEPT MENTION OF VCTS IN THE KAPF TAF. GUIDANCE ALSO INSISTING EAST FLOW TOO STRONG AND WILL INHIBIT THE WEST COAST SEA BREEZE FROM SETTING UP BUT THE WIND AT KAPF MAY BECOME MORE SSE AS THE CIRCULATION TRIES TO DEVELOP. KOB && .PREV DISCUSSION... /ISSUED 1021 AM EDT MON SEP 1 2014/ UPDATE... THE LATEST WATER VAPOR IMAGERY INDICATES THE MID TO UPPER LEVEL TROUGH CONTINUES TO RETROGRADE TO THE SOUTHWEST AND IS ENTERING THE NORTHWEST BAHAMAS. THIS IS BRINGING IN SOME DRIER MID TO UPPER LEVEL AIR INTO SOUTH FLORIDA AND ADJACENT WATERS THIS MORNING. RECENT RADAR RETURNS INDICATE ISOLATED SHOWER ACTIVITY MAINLY ACROSS THE ATLANTIC WATERS. MINOR UPDATES WERE DONE TO THE SHORT TERM FORECAST TO REFLECT THE CURRENT CONDITIONS. BUT AS THE AFOREMENTIONED TROUGH CONTINUES TO MOVE TO THE SOUTHWEST AND INTO THE REGIONAL ATLANTIC WATERS...THAT WILL LIKELY ALLOW FOR SOME POTENTIAL FOR CONVECTION. THERE IS CURRENTLY ACTIVE CONVECTION IN THE NORTHWEST BAHAMAS ISLANDS. SO THE FORECAST REFLECTS SCATTERED SHOWER/THUNDERSTORM ACTIVITY POSSIBLE OVER THE ATLANTIC WATERS AND EAST COAST METRO AREAS LATER THIS AFTERNOON WITH GREATER COVERAGE EXPECTED ACROSS THE WESTERN PENINSULA LATE THIS AFTERNOON WHERE THE SURFACE CONVERGENCE WILL BE MOST DOMINANT. SO OVERALL NO SIGNIFICANT CHANGES FROM PREVIOUS FORECAST OR SYNOPTIC REASONING EXCEPT FOR THE VERY SHORT TERM. 60 PREV DISCUSSION... /ISSUED 728 AM EDT MON SEP 1 2014/ AVIATION... MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST WITH A MODERATE EAST WIND FLOW. ANTICIPATED TSRA DEVELOPMENT WILL BE OVER THE INTERIOR WITH A WESTWARD PROPAGATION. AT THIS TIME, PLACED A VCTS IN THE KAPF TAF AFT 19Z AND THEY COULD HAVE A BRIEF MVFR OR EVEN IFR CIG/VSBY THROUGH THE AFTERNOON. EAST FLOW WILL PREVENT A SEA BREEZE ALONG THE SOUTHWEST COAST BUT WIND IS LIKELY TO VEER TO THE SSE AS IT TRIES TO FORM. KOB PREV DISCUSSION... /ISSUED 329 AM EDT MON SEP 1 2014/ HIGHLIGHTS... * MODERATE RISK OF RIP CURRENTS ATLANTIC BEACHES * SLIGHT TSTORM CHANCE EAST COAST, BETTER CHANCE GULF COAST TODAY * STORMIER PATTERN MID-LATE WEEK; STRONG STORMS POSSIBLE DISCUSSION... THE WEATHER PATTERN ON THIS LABOR DAY WILL REMAIN MOSTLY UNCHANGED FROM YESTERDAY. RIDGE AXIS WILL REMAIN OVER NORTH FLORIDA, MAINTAINING AN EASTERLY WIND FLOW LOCALLY WITH CONVECTIVE FOCUS ALONG THE GULF COAST IN THE AFTERNOON. LOW LEVEL WINDS WILL BE STRONG ENOUGH TO DISALLOW A FULL GULF SEA BREEZE FROM DEVELOPING, BUT SOME VEERING OF THE WIND FIELD IS EXPECTEDTHERE WHICH AGAIN WILL LEAD TO ENOUGH CONVERGENCE TO SPARK SOME TSTORM DEVELOPMENT. ACROSS THE EAST COAST, HRRR SHOWS A SCENARIO SIMILAR TO YESTERDAY WITH QUICK PASSING SHOWERS DEVELOPING. CANNOT RULE OUT TSTORMS EAST COAST BUT CONVERGENCE WILL BE LACKING SO COVERAGE WOULD BE ISOLATED AT BEST. LIKE YESTERDAY, A LIMITING FACTOR FOR MORE ACTIVE TSTORMS IS THE LACK OF A FULL FLEDGED ONSHORE GULF SEA BREEZE. HOWEVER, CANNOT RULE OUT A STRONG TSTORM OR TWO GIVEN SOME CONVERGENCE ALONG WITH THE INSTABILITY AND CONTINUED DRY AIR ALOFT. WIND GUSTS OF 40-50 MPH IS THE PRIMARY THREAT. A DEEP LAYERED TROUGH EAST OF THE BAHAMAS IS SHOWN BY THE GLOBAL MODELS TO MOVE WEST AND ACROSS SOUTH FLORIDA WED NIGHT-THU. THIS WILL BE ASSOCIATED WITH COOLING ALOFT ALONG WITH INCREASING MOISTURE, SPELLING A STORMIER PERIOD MID WEEK AND EVEN INTO LATE WEEK AS HIGHER INSTABILITY REMAINS. POPS ACCORDINGLY SHOW AN UPWARD TREND MID-LATE WEEK. COULD SEE SOME STRONG STORMS ANYWHERE BEGINNING WED THROUGH LATE WEEK DUE TO THE COLD AIR ALOFT AND TROUGH PASSAGE, THOUGH MORE CLOUDINESS WOULD BE A LIMITING FACTOR. /GREGORIA AVIATION... HIGH PRESSURE WILL SLOWLY WEAKEN OVER THE SOUTHEASTERN UNITED STATES TODAY WHICH IN TURN WILL KEEP A EASTERLY WIND FLOW OF AROUND 5 KNOTS THROUGH EARLY THIS MORNING AT ALL OF THE TAF SITES. THE WIND DIRECTION WILL REMAIN EASTERLY AFTER 14Z TODAY BUT INCREASE TO AROUND 10 KNOTS OVER ALL OF THE TAF SITES. THE WEATHER SHOULD REMAIN DRY THROUGH THE EARLY MORNING HOURS BEFORE SOME SHOWERS WORKS INTO THE EAST COAST TAF SITES AFTER 14Z. SO WILL PUT IN VCSH AFTER 14Z FOR THE EAST COAST TAF SITES. FOR KAPF TAF SITE...THE WEATHER WILL ALSO REMAIN DRY THROUGH MOST OF THIS LABOR DAY. HOWEVER...A LATE WEST COAST SEA BREEZE COULD DEVELOP AND PUSH INTO THE KAPF TAF SITE AFTER 21Z TODAY. SO WILL PUT IN VCTS BETWEEN 21Z AND 00Z TODAY. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS AT ALL OF THE TAF SITES FOR THIS LABOR DAY. MARINE...EAST SOUTHEAST WINDS LESS THAN 15 KT WILL PREVAIL AS THE ATLANTIC RIDGE REMAINS NORTH OF THE LOCAL WATERS. SEAS WILL BE CORRESPONDINGLY LOW. A TROUGH WILL MOVE ACROSS THE WATERS LATE WED- THU, BRINGING AN INCREASING CHANCE OF THUNDERSTORMS ESPECIALLY ACROSS THE ATLANTIC WATERS. && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MIAMI FL
1021 AM EDT MON SEP 1 2014 .UPDATE... THE LATEST WATER VAPOR IMAGERY INDICATES THE MID TO UPPER LEVEL TROUGH CONTINUES TO RETROGRADE TO THE SOUTHWEST AND IS ENTERING THE NORTHWEST BAHAMAS. THIS IS BRINGING IN SOME DRIER MID TO UPPER LEVEL AIR INTO SOUTH FLORIDA AND ADJACENT WATERS THIS MORNING. RECENT RADAR RETURNS INDICATE ISOLATED SHOWER ACTIVITY MAINLY ACROSS THE ATLANTIC WATERS. MINOR UPDATES WERE DONE TO THE SHORT TERM FORECAST TO REFLECT THE CURRENT CONDITIONS. BUT AS THE AFOREMENTIONED TROUGH CONTINUES TO MOVE TO THE SOUTHWEST AND INTO THE REGIONAL ATLANTIC WATERS...THAT WILL LIKELY ALLOW FOR SOME POTENTIAL FOR CONVECTION. THERE IS CURRENTLY ACTIVE CONVECTION IN THE NORTHWEST BAHAMAS ISLANDS. SO THE FORECAST REFLECTS SCATTERED SHOWER/THUNDERSTORM ACTIVITY POSSIBLE OVER THE ATLANTIC WATERS AND EAST COAST METRO AREAS LATER THIS AFTERNOON WITH GREATER COVERAGE EXPECTED ACROSS THE WESTERN PENINSULA LATE THIS AFTERNOON WHERE THE SURFACE CONVERGENCE WILL BE MOST DOMINANT. SO OVERALL NO SIGNIFICANT CHANGES FROM PREVIOUS FORECAST OR SYNOPTIC REASONING EXCEPT FOR THE VERY SHORT TERM. 60 && .PREV DISCUSSION... /ISSUED 728 AM EDT MON SEP 1 2014/ AVIATION... MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST WITH A MODERATE EAST WIND FLOW. ANTICIPATED TSRA DEVELOPMENT WILL BE OVER THE INTERIOR WITH A WESTWARD PROPAGATION. AT THIS TIME, PLACED A VCTS IN THE KAPF TAF AFT 19Z AND THEY COULD HAVE A BRIEF MVFR OR EVEN IFR CIG/VSBY THROUGH THE AFTERNOON. EAST FLOW WILL PREVENT A SEA BREEZE ALONG THE SOUTHWEST COAST BUT WIND IS LIKELY TO VEER TO THE SSE AS IT TRIES TO FORM. KOB PREV DISCUSSION... /ISSUED 329 AM EDT MON SEP 1 2014/ HIGHLIGHTS... * MODERATE RISK OF RIP CURRENTS ATLANTIC BEACHES * SLIGHT TSTORM CHANCE EAST COAST, BETTER CHANCE GULF COAST TODAY * STORMIER PATTERN MID-LATE WEEK; STRONG STORMS POSSIBLE DISCUSSION... THE WEATHER PATTERN ON THIS LABOR DAY WILL REMAIN MOSTLY UNCHANGED FROM YESTERDAY. RIDGE AXIS WILL REMAIN OVER NORTH FLORIDA, MAINTAINING AN EASTERLY WIND FLOW LOCALLY WITH CONVECTIVE FOCUS ALONG THE GULF COAST IN THE AFTERNOON. LOW LEVEL WINDS WILL BE STRONG ENOUGH TO DISALLOW A FULL GULF SEA BREEZE FROM DEVELOPING, BUT SOME VEERING OF THE WIND FIELD IS EXPECTEDTHERE WHICH AGAIN WILL LEAD TO ENOUGH CONVERGENCE TO SPARK SOME TSTORM DEVELOPMENT. ACROSS THE EAST COAST, HRRR SHOWS A SCENARIO SIMILAR TO YESTERDAY WITH QUICK PASSING SHOWERS DEVELOPING. CANNOT RULE OUT TSTORMS EAST COAST BUT CONVERGENCE WILL BE LACKING SO COVERAGE WOULD BE ISOLATED AT BEST. LIKE YESTERDAY, A LIMITING FACTOR FOR MORE ACTIVE TSTORMS IS THE LACK OF A FULL FLEDGED ONSHORE GULF SEA BREEZE. HOWEVER, CANNOT RULE OUT A STRONG TSTORM OR TWO GIVEN SOME CONVERGENCE ALONG WITH THE INSTABILITY AND CONTINUED DRY AIR ALOFT. WIND GUSTS OF 40-50 MPH IS THE PRIMARY THREAT. A DEEP LAYERED TROUGH EAST OF THE BAHAMAS IS SHOWN BY THE GLOBAL MODELS TO MOVE WEST AND ACROSS SOUTH FLORIDA WED NIGHT-THU. THIS WILL BE ASSOCIATED WITH COOLING ALOFT ALONG WITH INCREASING MOISTURE, SPELLING A STORMIER PERIOD MID WEEK AND EVEN INTO LATE WEEK AS HIGHER INSTABILITY REMAINS. POPS ACCORDINGLY SHOW AN UPWARD TREND MID-LATE WEEK. COULD SEE SOME STRONG STORMS ANYWHERE BEGINNING WED THROUGH LATE WEEK DUE TO THE COLD AIR ALOFT AND TROUGH PASSAGE, THOUGH MORE CLOUDINESS WOULD BE A LIMITING FACTOR. /GREGORIA AVIATION... HIGH PRESSURE WILL SLOWLY WEAKEN OVER THE SOUTHEASTERN UNITED STATES TODAY WHICH IN TURN WILL KEEP A EASTERLY WIND FLOW OF AROUND 5 KNOTS THROUGH EARLY THIS MORNING AT ALL OF THE TAF SITES. THE WIND DIRECTION WILL REMAIN EASTERLY AFTER 14Z TODAY BUT INCREASE TO AROUND 10 KNOTS OVER ALL OF THE TAF SITES. THE WEATHER SHOULD REMAIN DRY THROUGH THE EARLY MORNING HOURS BEFORE SOME SHOWERS WORKS INTO THE EAST COAST TAF SITES AFTER 14Z. SO WILL PUT IN VCSH AFTER 14Z FOR THE EAST COAST TAF SITES. FOR KAPF TAF SITE...THE WEATHER WILL ALSO REMAIN DRY THROUGH MOST OF THIS LABOR DAY. HOWEVER...A LATE WEST COAST SEA BREEZE COULD DEVELOP AND PUSH INTO THE KAPF TAF SITE AFTER 21Z TODAY. SO WILL PUT IN VCTS BETWEEN 21Z AND 00Z TODAY. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS AT ALL OF THE TAF SITES FOR THIS LABOR DAY. MARINE...EAST SOUTHEAST WINDS LESS THAN 15 KT WILL PREVAIL AS THE ATLANTIC RIDGE REMAINS NORTH OF THE LOCAL WATERS. SEAS WILL BE CORRESPONDINGLY LOW. A TROUGH WILL MOVE ACROSS THE WATERS LATE WED- THU, BRINGING AN INCREASING CHANCE OF THUNDERSTORMS ESPECIALLY ACROSS THE ATLANTIC WATERS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 90 79 90 77 / 30 20 40 20 FORT LAUDERDALE 91 80 90 80 / 30 20 50 20 MIAMI 90 80 89 78 / 30 20 50 20 NAPLES 91 76 91 76 / 60 30 60 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...30/KOB LONG TERM....60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
728 AM EDT MON SEP 1 2014 .AVIATION... MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST WITH A MODERATE EAST WIND FLOW. ANTICIPATED TSRA DEVELOPMENT WILL BE OVER THE INTERIOR WITH A WESTWARD PROPAGATION. AT THIS TIME, PLACED A VCTS IN THE KAPF TAF AFT 19Z AND THEY COULD HAVE A BRIEF MVFR OR EVEN IFR CIG/VSBY THROUGH THE AFTERNOON. EAST FLOW WILL PREVENT A SEA BREEZE ALONG THE SOUTHWEST COAST BUT WIND IS LIKELY TO VEER TO THE SSE AS IT TRIES TO FORM. KOB && .PREV DISCUSSION... /ISSUED 329 AM EDT MON SEP 1 2014/ HIGHLIGHTS... * MODERATE RISK OF RIP CURRENTS ATLANTIC BEACHES * SLIGHT TSTORM CHANCE EAST COAST, BETTER CHANCE GULF COAST TODAY * STORMIER PATTERN MID-LATE WEEK; STRONG STORMS POSSIBLE DISCUSSION... THE WEATHER PATTERN ON THIS LABOR DAY WILL REMAIN MOSTLY UNCHANGED FROM YESTERDAY. RIDGE AXIS WILL REMAIN OVER NORTH FLORIDA, MAINTAINING AN EASTERLY WIND FLOW LOCALLY WITH CONVECTIVE FOCUS ALONG THE GULF COAST IN THE AFTERNOON. LOW LEVEL WINDS WILL BE STRONG ENOUGH TO DISALLOW A FULL GULF SEA BREEZE FROM DEVELOPING, BUT SOME VEERING OF THE WIND FIELD IS EXPECTEDTHERE WHICH AGAIN WILL LEAD TO ENOUGH CONVERGENCE TO SPARK SOME TSTORM DEVELOPMENT. ACROSS THE EAST COAST, HRRR SHOWS A SCENARIO SIMILAR TO YESTERDAY WITH QUICK PASSING SHOWERS DEVELOPING. CANNOT RULE OUT TSTORMS EAST COAST BUT CONVERGENCE WILL BE LACKING SO COVERAGE WOULD BE ISOLATED AT BEST. LIKE YESTERDAY, A LIMITING FACTOR FOR MORE ACTIVE TSTORMS IS THE LACK OF A FULL FLEDGED ONSHORE GULF SEA BREEZE. HOWEVER, CANNOT RULE OUT A STRONG TSTORM OR TWO GIVEN SOME CONVERGENCE ALONG WITH THE INSTABILITY AND CONTINUED DRY AIR ALOFT. WIND GUSTS OF 40-50 MPH IS THE PRIMARY THREAT. A DEEP LAYERED TROUGH EAST OF THE BAHAMAS IS SHOWN BY THE GLOBAL MODELS TO MOVE WEST AND ACROSS SOUTH FLORIDA WED NIGHT-THU. THIS WILL BE ASSOCIATED WITH COOLING ALOFT ALONG WITH INCREASING MOISTURE, SPELLING A STORMIER PERIOD MID WEEK AND EVEN INTO LATE WEEK AS HIGHER INSTABILITY REMAINS. POPS ACCORDINGLY SHOW AN UPWARD TREND MID-LATE WEEK. COULD SEE SOME STRONG STORMS ANYWHERE BEGINNING WED THROUGH LATE WEEK DUE TO THE COLD AIR ALOFT AND TROUGH PASSAGE, THOUGH MORE CLOUDINESS WOULD BE A LIMITING FACTOR. /GREGORIA AVIATION... HIGH PRESSURE WILL SLOWLY WEAKEN OVER THE SOUTHEASTERN UNITED STATES TODAY WHICH IN TURN WILL KEEP A EASTERLY WIND FLOW OF AROUND 5 KNOTS THROUGH EARLY THIS MORNING AT ALL OF THE TAF SITES. THE WIND DIRECTION WILL REMAIN EASTERLY AFTER 14Z TODAY BUT INCREASE TO AROUND 10 KNOTS OVER ALL OF THE TAF SITES. THE WEATHER SHOULD REMAIN DRY THROUGH THE EARLY MORNING HOURS BEFORE SOME SHOWERS WORKS INTO THE EAST COAST TAF SITES AFTER 14Z. SO WILL PUT IN VCSH AFTER 14Z FOR THE EAST COAST TAF SITES. FOR KAPF TAF SITE...THE WEATHER WILL ALSO REMAIN DRY THROUGH MOST OF THIS LABOR DAY. HOWEVER...A LATE WEST COAST SEA BREEZE COULD DEVELOP AND PUSH INTO THE KAPF TAF SITE AFTER 21Z TODAY. SO WILL PUT IN VCTS BETWEEN 21Z AND 00Z TODAY. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS AT ALL OF THE TAF SITES FOR THIS LABOR DAY. MARINE...EAST SOUTHEAST WINDS LESS THAN 15 KT WILL PREVAIL AS THE ATLANTIC RIDGE REMAINS NORTH OF THE LOCAL WATERS. SEAS WILL BE CORRESPONDINGLY LOW. A TROUGH WILL MOVE ACROSS THE WATERS LATE WED- THU, BRINGING AN INCREASING CHANCE OF THUNDERSTORMS ESPECIALLY ACROSS THE ATLANTIC WATERS. && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MIAMI FL
329 AM EDT MON SEP 1 2014 .HIGHLIGHTS... * MODERATE RISK OF RIP CURRENTS ATLANTIC BEACHES * SLIGHT TSTORM CHANCE EAST COAST, BETTER CHANCE GULF COAST TODAY * STORMIER PATTERN MID-LATE WEEK; STRONG STORMS POSSIBLE .DISCUSSION... THE WEATHER PATTERN ON THIS LABOR DAY WILL REMAIN MOSTLY UNCHANGED FROM YESTERDAY. RIDGE AXIS WILL REMAIN OVER NORTH FLORIDA, MAINTAINING AN EASTERLY WIND FLOW LOCALLY WITH CONVECTIVE FOCUS ALONG THE GULF COAST IN THE AFTERNOON. LOW LEVEL WINDS WILL BE STRONG ENOUGH TO DISALLOW A FULL GULF SEA BREEZE FROM DEVELOPING, BUT SOME VEERING OF THE WIND FIELD IS EXPECTEDTHERE WHICH AGAIN WILL LEAD TO ENOUGH CONVERGENCE TO SPARK SOME TSTORM DEVELOPMENT. ACROSS THE EAST COAST, HRRR SHOWS A SCENARIO SIMILAR TO YESTERDAY WITH QUICK PASSING SHOWERS DEVELOPING. CANNOT RULE OUT TSTORMS EAST COAST BUT CONVERGENCE WILL BE LACKING SO COVERAGE WOULD BE ISOLATED AT BEST. LIKE YESTERDAY, A LIMITING FACTOR FOR MORE ACTIVE TSTORMS IS THE LACK OF A FULL FLEDGED ONSHORE GULF SEA BREEZE. HOWEVER, CANNOT RULE OUT A STRONG TSTORM OR TWO GIVEN SOME CONVERGENCE ALONG WITH THE INSTABILITY AND CONTINUED DRY AIR ALOFT. WIND GUSTS OF 40-50 MPH IS THE PRIMARY THREAT. A DEEP LAYERED TROUGH EAST OF THE BAHAMAS IS SHOWN BY THE GLOBAL MODELS TO MOVE WEST AND ACROSS SOUTH FLORIDA WED NIGHT-THU. THIS WILL BE ASSOCIATED WITH COOLING ALOFT ALONG WITH INCREASING MOISTURE, SPELLING A STORMIER PERIOD MID WEEK AND EVEN INTO LATE WEEK AS HIGHER INSTABILITY REMAINS. POPS ACCORDINGLY SHOW AN UPWARD TREND MID-LATE WEEK. COULD SEE SOME STRONG STORMS ANYWHERE BEGINNING WED THROUGH LATE WEEK DUE TO THE COLD AIR ALOFT AND TROUGH PASSAGE, THOUGH MORE CLOUDINESS WOULD BE A LIMITING FACTOR. /GREGORIA && .AVIATION... HIGH PRESSURE WILL SLOWLY WEAKEN OVER THE SOUTHEASTERN UNITED STATES TODAY WHICH IN TURN WILL KEEP A EASTERLY WIND FLOW OF AROUND 5 KNOTS THROUGH EARLY THIS MORNING AT ALL OF THE TAF SITES. THE WIND DIRECTION WILL REMAIN EASTERLY AFTER 14Z TODAY BUT INCREASE TO AROUND 10 KNOTS OVER ALL OF THE TAF SITES. THE WEATHER SHOULD REMAIN DRY THROUGH THE EARLY MORNING HOURS BEFORE SOME SHOWERS WORKS INTO THE EAST COAST TAF SITES AFTER 14Z. SO WILL PUT IN VCSH AFTER 14Z FOR THE EAST COAST TAF SITES. FOR KAPF TAF SITE...THE WEATHER WILL ALSO REMAIN DRY THROUGH MOST OF THIS LABOR DAY. HOWEVER...A LATE WEST COAST SEA BREEZE COULD DEVELOP AND PUSH INTO THE KAPF TAF SITE AFTER 21Z TODAY. SO WILL PUT IN VCTS BETWEEN 21Z AND 00Z TODAY. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS AT ALL OF THE TAF SITES FOR THIS LABOR DAY. && .MARINE...EAST SOUTHEAST WINDS LESS THAN 15 KT WILL PREVAIL AS THE ATLANTIC RIDGE REMAINS NORTH OF THE LOCAL WATERS. SEAS WILL BE CORRESPONDINGLY LOW. A TROUGH WILL MOVE ACROSS THE WATERS LATE WED- THU, BRINGING AN INCREASING CHANCE OF THUNDERSTORMS ESPECIALLY ACROSS THE ATLANTIC WATERS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 90 79 90 77 / 30 20 40 20 FORT LAUDERDALE 91 80 90 80 / 30 20 50 20 MIAMI 90 80 89 78 / 30 20 50 20 NAPLES 91 76 91 76 / 60 30 60 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...57/DG LONG TERM....57/DG AVIATION...54/BNB
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1029 PM EDT TUE SEP 2 2014 .UPDATE... AFTER AN EARLY START TO CONVECTION OVER THE ATLANTA METRO...FOCUS QUICKLY SHIFTED TO THE SOUTHEAST ZONES WHERE MIDDLE GEORGIA SAW NUMEROUS STRONG TO SEVERE THUNDERSTORMS. THIS ACTIVITY HAS SENT AN OUTFLOW NORTHWARD BACK TO THE METRO BUT NEWLY GENERATED ACTIVITY HAS BEEN HARD TO COME BY. HRRR DOES INDICATE NW ACTIVITY WILL SPREAD EASTWARD AND INTERACT WITH AFOREMENTIONED OUTFLOW BUT REMAINS UNCLEAR IF THIS WILL BE ENOUGH TO GENERATE ADDITIONAL OVERNIGHT THUNDERSTORM ACTIVITY. FOR NOW...HAVE PLAYED IT AS LOW END CHANCE POPS IN THE GRIDS FOR MOST LOCATIONS...EXCEPT NORTHWEST WHERE I HAVE GONE SLIGHTLY HIGHER GIVEN ADDED DYNAMICS IN PLAY. OTHERWISE FORECAST IS IN GOOD SHAPE AND NO CHANGES ARE PLANNED. DEESE && .PREV DISCUSSION... /ISSUED 817 PM EDT TUE SEP 2 2014/ PREV DISCUSSION... /ISSUED 301 PM EDT TUE SEP 2 2014/ SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... WEAK IMPULSE IN THE FLOW PUSHING ACROSS THE EASTERN CONUS TODAY AND THIS MAY HELP THE SHOWERS AND THUNDERSTORMS ACROSS NORTH GEORGIA CONTINUE INTO TONIGHT. AFTER THIS THOUGH...NO SIGNIFICANT FEATURE AT THE UPPER LEVELS TO KEY IN ON IN THE SHORT TERM. BASICALLY WILL CONTINUE AGAIN TOMORROW WITH THE DIURNALLY DRIVEN THUNDERSTORMS IN THE AFTERNOON AND EVENING. WITH MUCAPE VALUES OVER 2000 J/KG WEDNESDAY AFTERNOON...STRONG TO ISOLATED SEVERE STORMS WILL BE POSSIBLE. THE MAIN THREATS TOMORROW AFTERNOON APPEAR TO BE GUSTY WINDS AND LOCALLY HEAVY RAINFALL. FAIRLY BIG DISCREPANCIES IN THE TEMPERATURE GUIDANCE FOR TOMORROW WITH THE MAV BEING WARMER THAN THE MET. AT ATL...THERE IS A SIX DEGREE TEMPERATURE DIFFERENCE BETWEEN THESE TWO FOR HIGHS TOMORROW AFTERNOON. MUCH OF THIS IS CAUSED BY MORE CLOUD COVERAGE DEPICTED BY THE NAM. THINK THE NAM IS OVERDOING CLOUD COVERAGE THOUGH SO STARTED WITH A BLEND...AND THEN LEANED TOWARDS THE WARMER SIDE FOR HIGH TEMPS TOMORROW. ONCE AGAIN BOTH HIGH AND LOW TEMPERATURES WILL BE ABOVE NORMAL. 11 LONG TERM /THURSDAY THROUGH TUESDAY/... NO CHANGES TO THE CURRENT LONG TERM. SEE PREVIOUS DISCUSSION BELOW... 17 LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... /ISSUED 325 AM EDT TUE SEP 2 2014/ SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EXPECTED EACH DAY THROUGH THE LONG TERM. WEAK TROUGH STILL IN PLACE ACROSS CENTRAL GA WEDNESDAY NIGHT...BUT WILL EVENTUALLY DISSIPATE ON THURSDAY. ALOFT...A WEAK SHEAR AXIS WILL REMAIN THROUGH FRIDAY. THE DISSIPATING BOUNDARY AND SHEAR AXIS ALOFT MAY SERVE TO FOCUS ANY CONVECTION THURSDAY INTO FRIDAY. A WEAK FRONT IS STILL ON TRACK FOR THE MID TO LATE WEEKEND. WITH SUCCESSIVE RUNS...THE MODELS HAVE SLOWED THE SOUTHWARD PROGRESS OF THE BOUNDARY. CURRENTLY...THE FRONT SHOULD MOVE ACROSS NORTHERN GA LATE SATURDAY/EARLY SUNDAY THEN STALL ACROSS CENTRAL GA BY LATE SUNDAY/EARLY MONDAY. THE FRONT LOOKS TO BECOME DIFFUSE BY TUESDAY. TEMPS STILL EXPECTED TO BE ABOVE NORMAL THROUGH THE PERIOD. NLISTEMAA AVIATION... 00Z UPDATE... TSRA WHICH AFFECTED THE ATL TERMINALS EARLIER THIS AFTERNOON HAVE SHIFTED WELL SOUTH TO AFFECT THE SOUTHERNMOST TERMINALS. OUTFLOW BOUNDARIES COMBINED WITH APPROACHING SEABREEZE MAY KEEP ACTIVITY IN THE MCN VICINITY THROUGH MIDNIGHT. OTHERWISE...ANOTHER ROUND OF TSRA WITH SIMILAR TIMING ON WEDNESDAY WARRANTS INCLUSION OF A PROB30 WHICH WILL IN ALL LIKELIHOOD TRANSITION TO A TEMPO TSRA WITH SUBSEQUENT FORECASTS. //ATL CONFIDENCE...00Z UPDATE... HIGH ON ALL ELEMENTS. DEESE && .PRELIMINARY POINT TEMPS/POPS... ATHENS 70 95 71 92 / 30 40 30 40 ATLANTA 73 90 73 88 / 30 40 40 40 BLAIRSVILLE 66 86 66 84 / 30 40 30 40 CARTERSVILLE 68 91 69 90 / 40 30 30 40 COLUMBUS 73 94 74 90 / 30 40 40 30 GAINESVILLE 71 90 72 89 / 30 40 30 40 MACON 71 94 71 92 / 60 40 40 30 ROME 68 92 69 91 / 40 30 30 40 PEACHTREE CITY 68 90 70 88 / 50 40 40 40 VIDALIA 73 95 73 92 / 20 40 30 30 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DEESE LONG TERM....30 AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
149 PM EDT MON SEP 1 2014 .SYNOPSIS... SURFACE HIGH PRESSURE WILL EXTEND INTO THE FORECAST AREA FROM THE ATLANTIC THROUGH THE MIDDLE OF THE WEEK. A PERSISTENT UPPER RIDGE WILL HELP MAINTAIN THE HOT TEMPERATURES. && .NEAR TERM /THROUGH TONIGHT/... VISIBLE IMAGERY EARLY THIS AFTERNOON SHOWING LESS CUMULUS COVERAGE THAN 24 HOURS AGO AND THIS MAY BE ATTRIBUTED TO HIGHER CONVECTIVE TEMPS IN THE MID 90S TODAY...SOME DRIER AIR NOTED AT 850MB...AND PRECIPITABLE WATER VALUES AROUND 1.7 INCHES. ENHANCED CUMULUS AND SOME ISOLATED SHOWERS BEING OBSERVED OVER CENTRAL GEORGIA WHERE MOISTURE IS BETTER. CURRENTLY WEAK INSTABILITY ACROSS THE AREA WITH LIFTED INDEX VALUES AROUND -3C TO -5C BUT LAPSE RATES CONTINUE TO RISE AND ARE UP TO 7.5 C/KM. SUCCESSIVE RUNS OF THE HRRR CONTINUE TO SHOW LITTLE CONVECTION OVER THE FORECAST AREA LATE THIS AFTERNOON AND TONIGHT...WHILE THE LATEST 12Z SPC WRF RUN IS VERY SIMILAR TO ITS 00Z RUN SHOWING CONVECTION DEVELOPING IN THE CSRA AND WESTERN MIDLANDS LATE AFTERNOON AND DRIFTING SOUTHEAST AND MERGING WITH SEA BREEZE CONVECTION OVER THE LOWER CSRA AND SOUTHEASTERN MIDLANDS. WILL MAINTAIN SLIGHT CHANCE POPS ACROSS THE NORTHERN AND CENTRAL MIDLANDS WHILE KEEPING LOW CHANCE POPS IN THE MORE FAVORABLE AREA OF THE CSRA AND SOUTHEASTERN MIDLANDS 21Z-02Z. CANNOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM AND WEAK STORM MOTION WILL PROVIDE A LOCALLY HEAVY RAIN AND POSSIBLE FLOODING THREAT WHERE STORMS TRAIN OR REMAIN NEARLY STATIONARY. EXPECT SOME CONVECTIVE DEBRIS CLOUDS AROUND OVERNIGHT WHICH WILL HELP LIMIT FOG POTENTIAL AND EXPECT OVERNIGHT LOWS IN THE MID 70S. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... SURFACE RIDGING SHOULD CONTINUE EAST AND SOUTH OF THE FORECAST AREA. EXPECT WEAK LEE-SIDE TROUGHING IN THE AREA. STRONG HEATING AND CONVERGENCE INTO THIS FEATURE SHOULD HELP SUPPORT THUNDERSTORMS...BUT CONTINUED UPPER RIDGING SHOULD LIMIT COVERAGE. ALSO...THE SURFACE FEATURE SHOULD REMAIN WEAK. THE NAM AND GFS MOS HAVE LOW POPS WITH THE CONSENSUS AROUND 20 PERCENT. IT WILL REMAIN HOT. USED THE WARMER TEMPERATURE GUIDANCE BASED ON RECENT VERIFICATION. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE GFS AND ECMWF SHOW A WEAKENING FRONT STALLING BEFORE REACHING THE AREA DURING THE MIDDLE OF THE WEEK. THE MODELS SHOW ANOTHER FRONT MAY REACH THE AREA LATE IN THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER-LEVEL RIDGING CONTINUING. THE GFS...ECMWF...AND EKD MOS SHOW ABOVE NORMAL TEMPERATURES WITH POPS 20 TO 30 PERCENT THROUGH THE PERIOD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... HIGHER CONVECTIVE TEMPS TODAY ALONG WITH SOME DRIER AIR AT 850MB HAS RESULTED IN A LATER START TO THE CUMULUS DEVELOPMENT BUT IT IS UNDERWAY WITH WEAK TO MODERATE INSTABILITY IN PLACE. ISOLATED CONVECTION IS EXPECTED BUT LOW CONFIDENCE IN ANY STORMS IMPACTING TERMINALS SO NOT IN THE FORECAST AT THIS TIME. EXPECT VFR CONDITIONS THROUGHOUT THE FORECAST PERIOD EXCEPT FOR SOME MVFR FOG AT FOG PRONE AGS/OGB...FOG APPEARS LESS LIKELY AT CAE/CUB/DNL. LIGHT SOUTHERLY WINDS THIS AFTERNOON WILL BECOME NEAR CALM OVERNIGHT AND PICK UP FROM THE SOUTH AGAIN AFTER 15Z TUESDAY...LESS THAN 5 KNOTS. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN LATE NIGHT AND EARLY MORNING STRATUS AND FOG. SCATTERED MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ NEAR TERM...HC AVIATION...HC
AREA FORECAST DISCUSSION...UPDATED
NWS COLUMBIA SC
1106 AM EDT MON SEP 1 2014 .SYNOPSIS... SURFACE HIGH PRESSURE WILL EXTEND INTO THE FORECAST AREA FROM THE ATLANTIC THROUGH THE MIDDLE OF THE WEEK. A PERSISTENT UPPER RIDGE WILL HELP MAINTAIN THE HOT TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NOT MUCH HAS CHANGED IN THE ATMOSPHERE OVER THE PAST 24 HOURS REGARDING THE OVERALL WEATHER PATTERN OVER THE REGION. SURFACE HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL CONTINUE TO RIDGE INTO THE FORECAST AREA TODAY WITH GENERALLY MOIST SOUTHERLY FLOW. IN THE UPPER LEVELS...THE RIDGE AXIS HAS SHIFTED SLIGHTLY TO THE EAST TOWARDS THE COAST IN RESPONSE TO SHORTWAVE ENERGY PUSHING INTO THE OHIO/TENNESSEE VALLEYS. MORNING MESOANALYSIS SHOWS A PRECIPITABLE WATER GRADIENT ACROSS THE REGION FROM 1.5 INCHES IN THE WESTERN MIDLANDS TO 1.8 INCHES IN THE EASTER MIDLANDS WITH A POCKET OF DRY AIR AROUND 850MB IN THE UPSTATE INTO THE WESTERN MIDLANDS. DESPITE THE UPPER RIDGING OVER THE REGION...THE NAM SHOWS A SHORTWAVE TROUGH MOVING INTO THE RIDGE OVER THE FORECAST AREA LATE THIS AFTERNOON AND EVENING. THE COMBINATION OF STRONG HEATING...WEAK CONVERGENCE INTO THE LEE-SIDE TROUGH...AND ABUNDANT LOW LEVEL MOISTURE IN PLACE SHOULD SUPPORT LATE DAY THUNDERSTORM DEVELOPMENT...ALTHOUGH UNCERTAINTY REMAINS ABOUT THE OVERALL COVERAGE. THE SPC WRF SHOWS SCATTERED COVERAGE IN THE AFTERNOON BECOMING WIDESPREAD DURING THE EVENING...WHILE THE LATEST HRRR AND LOCAL OFFICE HI-RES WRF ARE VERY LIMITED WITH ANY CONVECTION. WILL FAVOR HIGHEST POPS...CHANCE 30-40 PERCENT...IN THE SOUTHEASTERN MIDLANDS AND CSRA WITH SLIGHT CHANCE POPS ELSEWHERE LATE AFTERNOON INTO THE EVENING. SLOW STORM MOTION AND RECOVERING PRECIPITABLE WATER VALUES NEAR 2 INCHES WILL SUPPORT LOCALLY HEAVY RAIN. CANNOT RULE OUT AN ISOLATED SEVERE STORM OR TWO OR LOCALIZED FLOODING DUE TO MODERATE INSTABILITIES. TEMPERATURES ARE QUICKLY RISING AGAIN THROUGH THE UPPER 80S AT THIS TIME AND WILL REACH THE MID TO UPPER 90S AGAIN TODAY. WENT ABOVE MOS GUIDANCE WHICH HAS SHOWN A COOL BIAS FOR SEVERAL DAYS. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... SURFACE RIDGING SHOULD CONTINUE EAST AND SOUTH OF THE FORECAST AREA. EXPECT WEAK LEE-SIDE TROUGHING IN THE AREA. STRONG HEATING AND CONVERGENCE INTO THIS FEATURE SHOULD HELP SUPPORT THUNDERSTORMS...BUT CONTINUED UPPER RIDGING SHOULD LIMIT COVERAGE. ALSO...THE SURFACE FEATURE SHOULD REMAIN WEAK. THE NAM AND GFS MOS HAVE LOW POPS WITH THE CONSENSUS AROUND 20 PERCENT. IT WILL REMAIN HOT. USED THE WARMER TEMPERATURE GUIDANCE BASED ON RECENT VERIFICATION. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE GFS AND ECMWF SHOW A WEAKENING FRONT STALLING BEFORE REACHING THE AREA DURING THE MIDDLE OF THE WEEK. THE MODELS SHOW ANOTHER FRONT MAY REACH THE AREA LATE IN THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER-LEVEL RIDGING CONTINUING. THE GFS...ECMWF...AND EKD MOS SHOW ABOVE NORMAL TEMPERATURES WITH POPS 20 TO 30 PERCENT THROUGH THE PERIOD. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... SOME LINGERING CONVECTIVE DEBRIS CLOUDS AROUND THE AREA BUT VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF THE FORECAST PERIOD OUTSIDE OF SCATTERED SHOWERS AND THUNDERSTORMS WHICH MAY IMPOSE BRIEF MVFR/IFR CONDITIONS. THE CONFIDENCE IN ANY STORMS IMPACTING ANY TERMINAL IS LOW AND THEREFORE NOT FORECAST AT THIS TIME BUT SCATTERED CONVECTION IS EXPECTED AFTER 20Z. LIGHT AND VARIABLE WINDS WILL BECOME MORE SOUTHERLY BY AFTERNOON BEFORE GOING LIGHT AND VARIABLE TO CALM AGAIN OVERNIGHT. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN LATE NIGHT AND EARLY MORNING STRATUS AND FOG. SCATTERED MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS TUESDAY THROUGH FRIDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ NEAR TERM...HC AVIATION...HC
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
104 PM CDT MON SEP 1 2014 .DISCUSSION... 1115 AM CDT FOR MORNING UPDATE... THUNDERSTORM AND SEVERE WEATHER THREAT APPEARS TO HAVE DIMINISHED SIGNIFICANTLY FOR MUCH OF THE FORECAST AREA TODAY...DUE TO CLOUD COVER AND DRIER AIR WHICH HAS SPREAD EAST ACROSS NORTHERN IL WITH OUTFLOW FROM OVERNIGHT MCS TO OUR WEST. SEE UPDATED SPC DAY 1 OUTLOOK WHICH REMOVES SLIGHT RISK GENERALLY ALONG/WEST OF I-57. HAVE ALSO BOOSTED TEMPS ACROSS THE SOUTHEAST TO THE LOW-MID 80S WHERE TEMPS QUICKLY WARMING. LEAD SHORT WAVE...POSSIBLY ENHANCED BY MCS/MCV FROM NOCTURNAL MCS OVER IOWA...HAS MOVED INTO NORTHERN IL THIS MORNING ACCOMPANIED BY A PRE-FRONTAL TROUGH AND SHIFT TO WESTERLY WINDS GENERALLY WEST OF THE FOX RIVER VALLEY AS OF 11 AM. EXTENSIVE CLOUD COVER..AND LOWER SFC DEW POINTS BEHIND THE BOUNDARY HAVE STABILIZED ATMOSPHERE...WITH HIGHER THETA-E AIR CHARACTERIZED BY LOWER 70S DEW POINT TEMPS NOW MAINLY ALONG/EAST OF THE INTERSTATE 57 CORRIDOR. WHILE SOME EROSION OF CLOUD COVER WAS NOTED ACROSS WESTERN IL...IT APPEARS THAT THE MAIN INSTABILITY AXIS WILL BE ACROSS THE FAR EASTERN CWA AND AREAS FARTHER EAST. HIGH-RES CONVECTION ALLOWING GUIDANCE INCLUDING THE HRRR AND NATIONAL/LOCAL ARW RUNS INDICATE LITTLE IN THE WAY OF ROBUST CONVECTION DEVELOPING ACROSS NORTHERN IL...WITH DIURNAL DESTABILIZATION AND STRONGER THUNDERSTORM INITIATION FOCUSED EARLY THIS AFTERNOON ALONG OUR EASTERN CWA BOUNDARY. THUS IT APPEARS OUR SEVERE WEATHER THREAT HAS DECREASED SIGNIFICANTLY...AND SPC HAS REMOVED MUCH OF THE CWA WEST OF I-57 FROM THEIR DAY 1 SLIGHT RISK. THE SYNOPTIC COLD FRONT STILL REMAINS TO OUR WEST...FROM JUST EAST OF THE TWIN CITIES TO SOUTHWEST IOWA AT 11 AM...AND THIS WILL MOVE EAST THROUGH THE AFTERNOON AND EVENING. GUIDANCE DOES DEPICT A LINE OF SHOWERS/ISOLATED THUNDERSTORMS DEVELOPING AHEAD OF THE FRONT LATE THIS AFTERNOON AND EVENING...THOUGH SEVERE THREAT APPEARS VERY LOW IN RATHER WEAK MLCAPE ENVIRONMENT. POTENTIAL FOR STRONGER STORM DEVELOPMENT DOES REMAIN LATER TONIGHT ALONG THE FRONT AS MAIN SHORT WAVE MOVES ACROSS THE AREA...THOUGH TRENDS FROM 12Z GUIDANCE INDICATE ONLY A SMALL PORTION OF OUR SOUTHEAST CWA MAY BE AFFECTED. HAVE TRIMMED BACK POPS QUITE A BIT ACROSS THE NORTHERN 3/4 OR SO OF THE CWA AND MAY BE ABLE TO TRIM EVEN FURTHER DEPENDING ON TRENDS OVER THE NEXT FEW HOURS. RATZER //PREV DISCUSSION... 340 AM CDT ENTERING SEPTEMBER AND METEOROLOGICAL AUTUMN WE STILL FIND THE FORECAST CHALLENGES TO BE MORE SUMMER-LIKE...AT LEAST EARLY ON IN THE FORECAST. THAT IS STORM AND HEAVY RAIN POTENTIAL TODAY AND TONIGHT...THEN STORM CHANCES WEDNESDAY NIGHT AND FRIDAY WHICH SANDWICH A POSSIBLE 90 PLUS DEGREE DAY ON THURSDAY. LESS BUT STILL SOME TIME WAS SPENT ON THE FINAL CHALLENGE OF HOW MUCH OF A COOL DOWN OCCURS THE FIRST FULL WEEKEND OF THIS NEW METEOROLOGICAL SEASON. SYNOPSIS... A LONG WAVE TROUGH EXTENDING SOUTHWARD THROUGH CANADA INTO THE NORTH CENTRAL U.S. HAS A VERY PROGRESSIVE SHORT WAVE FEATURE MOVING THROUGH ITS SOUTHERN BASE. THIS IS SPEEDING EAST-NORTHEAST ACROSS IA EARLY THIS MORNING. A SURFACE COLD FRONT MOVING EAST LAGS THIS SHORT WAVE...EXTENDING FROM NORTHERN MN THROUGH THE TX PANHANDLE EARLY THIS MORNING...WITH MULTIPLE SURFACE WAVES IN THE 1003MB NEIGHBORHOOD ALONG IT. NORTHWEST SURFACE FLOW BEHIND THIS FRONT IS NOT PARTICULARLY STRONG SO THIS FRONT WILL CONTINUE TO BE A SLOW- MOVER TODAY...NOT EXPECTED TO ENTER THE FORECAST AREA UNTIL THIS EVE. BEING WITHIN A WARM SECTOR UNDER QUICKENING UPPER/MID-LEVEL FLOW PRESENTS THE STORM CHANCES THESE 24 HOURS. THIS MORNING... A LOOSELY DEFINED MCS MOVING EASTWARD INTO NORTHWEST IL EARLY THIS MORNING WANED CONSIDERABLY WITH WARMING CLOUD TOPS AND OUTFLOW EXTENDING WELL AHEAD OF IT. SEEING AN UPTICK ACROSS WEST CENTRAL IL LIKELY ASSOCIATED WITH LIFT OF THE AFOREMENTIONED PROGRESSIVE SHORT WAVE. HIGH RESOLUTION MODELS GREATLY VARY ON WHAT WILL HAPPEN EVEN JUST A FEW HOURS OUT...BUT WOULD EXPECT SYNOPTICALLY TO SEE SOME CONVECTION EVOLVE INTO THE FORECAST AREA THIS MORNING...POSSIBLY ONLY THE WESTERN/SOUTHWESTERN AREA BUT STILL CANT RULE OUT SCATTERED ACTIVITY MOVING EASTWARD THROUGH THE ENTIRE AREA INCLUDING CHICAGO DURING MID/LATE MORNING. DESPITE A FAIRLY STRONG LOW-LEVEL JET INTO ANY ACTIVITY...THE CONTINUED BROAD AREA OF STORMS ACROSS EASTERN KS INTO WEST/SOUTHWEST MO THROUGH EARLY TO MID MORNING SHOULD LESSEN MOISTURE TRANSPORT AND THUS ABILITY TO REALIZE STEEP LAPSE RATES ALOFT FOR MORE ROBUST ACTIVITY...AND MAYBE EVEN THUNDER IN GENERAL NORTH OF INTERSTATE 80. THIS AFTERNOON AND TONIGHT... DESPITE THIS BEING IN THE FIRST 12 HOURS OF THE FORECAST...DUE TO INFLUENCE OF MORNING STORMS AND LARGE MODEL DIFFERENCES...CONFIDENCE ON SPECIFICS IN THESE PERIODS REMAIN LOW. THERE SHOULD BE SOME FORM OF OUTFLOW BOUNDARY OR BOUNDARIES FROM MORNING ACTIVITY/CLOUD COVER THAT LINGER INTO THE FORECAST AREA INTO THE AFTERNOON...MOST FAVORED SOUTH OF INTERSTATE 80. AS WARMING AND DESTABILIZATION OCCURS WITH DEW POINTS AROUND 70F...COULD SEE SCATTERED ACTIVITY DEVELOP NEAR ANY SUCH BOUNDARIES DURING THE MID TO LATE AFTERNOON. THE SECOND UPPER WAVE ACROSS WESTERN WY THIS MORNING WILL BEGIN TO APPROACH THE REGION AS WELL BY LATE IN THE DAY...WITH FORCING FROM THIS POSSIBLY AIDING IN SCATTERED STORM DEVELOPMENT ACROSS MUCH OF THE REGION. EVEN EARLY THIS MORNING THERE ARE A HANDFUL OF STORMS ACROSS THE UPPER MIDWEST NOT LINKED TO ANY SPECIFIC SURFACE FEATURE. INCREASING DEEP LAYER SHEAR OF 35 TO 50 KT WILL SUPPORT ISOLATED TO SCATTERED SEVERE DISCRETE STORMS IN THE REGION. WHILE IT REMAINS DIFFICULT TO PINPOINT TIMING...IT WOULD SEEM THE GREATEST COVERAGE IN REDEVELOPING STORMS THIS EVENING WOULD BE IN THE SOUTHERN FORECAST AREA WHERE AFOREMENTIONED BOUNDARY MAY OCCUR AND MODEST SOUTHWEST 850-925MB FLOW AND MOISTURE TRANSPORT REMAINS. AS THE AREA BECOMES UNDER A RIGHT ENTRANCE REGION TO THE UPPER JET...DO EXPECT INCREASING ASCENT TONIGHT IN THE REGION FOR MORE ROBUST CONVECTION AND POTENTIAL SEVERE AND HEAVY RAIN THREATS. RIGHT NOW A GUIDANCE OVERLAP WOULD INDICATE THE FAR SOUTHEAST FORECAST AREA IS MOST FAVORED FOR THIS. PRECIPITABLE WATERS AROUND TWO INCHES AND STORM MOTIONS NEARLY PARALLEL TO THE UPPER AND MID LEVEL FLOW WILL PRESENT HEAVY RAIN THREATS IN THE GENERAL CENTRAL TO SOUTHERN IL INTO IN REGIONS...BUT AGAIN AT THIS TIME CONFIDENCE VARIES ON PLACEMENT. BECAUSE OF THAT WILL CONTINUE WITH THE HYDROLOGIC OUTLOOK /ESF/ FOR THE AREAS HIT HARD ON SATURDAY NIGHT WITH HEAVY RAINFALL. TUESDAY AND WEDNESDAY... THE FRONT SHOULD CLEAR THE FORECAST AREA SOMETIME TUESDAY MORNING. WHILE DRY AIR ADVECTION WILL OCCUR...LIMITED CONVERGENCE REMAINS IN THE SOUTHEAST FORECAST AREA FOR POSSIBLY A STORM OR TWO TUESDAY BUT IT LOOKS TO BE A LOW CHANCE. TEMPERATURES ONLY COOL SLIGHTLY AS HIGH PRESSURE QUICKLY MOVES ATOP THE AREA TUESDAY NIGHT AND THEN EASTWARD. WEDNESDAY NIGHT THROUGH FRIDAY... WARM AIR ADVECTION AND A RAPID PRECIPITABLE WATER INCREASE IS FORECAST WEDNESDAY NIGHT ON ALL GUIDANCE. FEEL THAT MODELS MAY BE UNDER-DOING THE STORM CHANCES GIVEN FORECAST PROFILES OF STEEPENING LAPSE RATES WITHIN A RAPIDLY MOISTENING COLUMN...AT LEAST IN THE WESTERN FORECAST AREA. SO HAVE INCREASED POPS IN THAT AREA. AS FOR THURSDAY...HAVE GONE DRY IN MANY AREAS COLLABORATING AND UNDERCUTTING A MODEL BLEND OF POPS. THE SYNOPTIC PATTERN FAVORS A HOT DAY AND BARRING ANY STRATUS ISSUES WITH WEDNESDAY NIGHTS WARM AIR ADVECTION AND POSSIBLE PRECIP...SHOULD SEE THE 90 DEGREE MARK REACHED OR EXCEEDED ACROSS A GOOD PART OF THE FORECAST AREA BASED ON STRONG SOUTHWEST FLOW AND FORECAST 850MB AND 925MB TEMPERATURES COMPARED TO CLIMATOLOGY. FOR NOW HAVE KEPT THE NORTH A LITTLE BELOW THAT WITH THE POSSIBILITY OF MORNING CLOUDS. THE SYSTEM COLD FRONT IS PRESENTLY FORECAST BY THE EC AND THE GFS TO COME THROUGH THE AREA SOMETIME ON FRIDAY WHICH WOULD BRING STORM CHANCES WITH IT...AS WELL AS FLOW TURNING OFF THE LAKE BEHIND ITS PASSAGE. BEYOND... NO CHANGES MADE TO THIS WEEKEND WHERE HIGHS LOOK TO BE AROUND 70 WITH DRY CONDITIONS BEHIND THE AFOREMENTIONED FRONT. HIGH PRESSURE AROUND 1023MB IS FORECAST BY A BLEND OF GUIDANCE. GIVEN THE 925MB TEMPERATURES FORECAST IF THAT HIGH IS CENTERED OVER THE FORECAST AREA SOMETIME SUNDAY OR MONDAY NIGHTS /7TH OR 8TH/...LOWS IN OUTLYING AREAS WOULD LIKELY BE IN THE 40S. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * TSRA CHANCES THIS AFTERNOON AND EVENING. * CEILING TRENDS THIS AFTERNOON. * MORE SHRA AND TSRA POSSIBLE TOWARD EVENING. LENNING //DISCUSSION...UPDATED 18Z... CONVECTION HAS BLOSSOMED ALONG A LINE OVER LOWER MI BUT MANAGED TO AVOID MOST OF THE LOCAL AREA THIS MORNING. AN ADDITIONAL CLUSTER OF STORMS IS STARTING TO FORM OVER NORTHEAST IOWA ALONG A COLD FRONT THAT IS MOVING THIS DIRECTION. TIMING OF THE IOWA ACTIVITY INTO THE LOCAL AREA IS UNCERTAIN...BUT FEEL THAT 00Z TO 03Z IS A GOOD FIRST ESTIMATE AT ORD AND MDW AS PER 18Z TAF. CEILINGS HAVE SCATTERED EXCEPT FOR SOME LINGERING MVFR...BUT AM NOT CONFIDENT THAT SCT-CLR SKIES WILL BE WIDESPREAD THIS AFTERNOON GIVEN THE AMOUNT OF MOISTURE IN THE AIR. AREAS THAT HAD CLEARED EARLIER ARE ALREADY STARTING TO FILL BACK IN WITH DIURNAL HEATING...BUT FOR THE MOST PART ARE STAYING VFR. OVERNIGHT TOWARD MORNING THERE IS A CHANCE OF LOWER VSBYS WITH LIGHT WINDS AND MOIST AIR IN PLACE...BUT GUIDANCE SHOWS BETTER CHANCES TOWARD RFD THAN IN THE MDW/ORD TERMINALS...LIKELY DUE TO BETTER COOLING THAN IN THE CITY. HAVE NOT PUT THIS IN THE TAFS YET BUT WILL MONITOR FOR LATER INCLUSION. LENNING //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO HIGH CONFIDENCE FOR ALL ELEMENTS. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...PREDOMINANTLY VFR. FRIDAY...CHANCE OF SHRA/TSRA. SATURDAY AND SUNDAY...PREDOMINANTLY VFR. KJB && .MARINE... 232 AM CDT IT LOOKS TO BE AN ACTIVE WEATHER DAY ACROSS THE LAKE...WITH STOUT SOUTHERLY WINDS LAKE-WIDE...AND THE THREAT FOR SOME STRONG TO SEVERE THUNDERSTORMS ACROSS SOUTHERN LAKE MICHIGAN. THESE STRONG SOUTHERLY WINDS WILL RESULT IN WINDS AROUND 25 KT AND THE ONGOING SMALL CRAFT ADVISORY STILL APPEARS GOOD. THE SURFACE LOW...RESPONSIBLE FOR THESE STRONG SOUTHERLY WINDS TODAY...WILL SHIFT ACROSS ONTARIO...AND TO NEAR JAMES BAY BY THIS EVENING WHILE DEEPENING TO AROUND 29.2 INCHES. AS THIS OCCURS...AN ASSOCIATED COLD FRONT WILL BE DRAWN EASTWARD ACROSS THE LAKE BY EARLY TUESDAY MORNING. WINDS WILL BECOME WESTERLY AND ABATE SIGNIFICANTLY WITH THE PASSAGE OF THIS FRONT. ANOTHER PERIOD OF STRONGER SOUTHERLY WINDS LOOKS TO SET UP AGAIN WEDNESDAY NIGHT AND THURSDAY AS ANOTHER POTENT AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS ONTARIO. WINDS SPEEDS COULD AGAIN BE AROUND 25 KT OUT OF THE SOUTH DURING THIS PERIOD. ANOTHER STRONGER COLD FRONT LOOKS TO SHIFT DOWN THE LAKE IN THE WAKE OF THIS LOW LATE FRIDAY AND THIS COULD SET THE STAGE FOR A DECENT NORTHERLY WIND EVENT ACROSS THE LAKE AS A STOUT AREA OF HIGH PRESSURE QUICKLY BUILDS EASTWARD ACROSS THE UPPER MIDWEST. STRONG NORTHERLY WINDS OF 25 TO 30 KT APPEAR QUITE POSSIBLE IN THE WAKE OF THIS COLD FRONT FRIDAY NIGHT INTO SATURDAY...WHICH WOULD ALSO RESULT IN LARGE WAVES IN EXCESS OF 5 FEET ACROSS SOUTHERN LAKE MICHIGAN INTO NEXT WEEKEND. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1249 PM CDT Mon Sep 1 2014 .UPDATE... ISSUED AT 1001 AM CDT MON SEP 1 2014 Line of strong to severe thunderstorms tracked across Iowa last night, then rapidly dissipated as it pushed toward the Mississippi River early this morning. Outflow boundary from this dying convection is currently approaching the I-55 corridor as evidenced by westerly winds across all sites in the Illinois River Valley. Think this outflow will eventually serve as the primary focus for additional thunderstorm development later today. Still some question as to exactly where the boundary will lay out and when convection will fire, but the latest thinking from SPC has pushed the best severe weather risk much further southeast, generally along/south of a Danville to Jacksonville line. HRRR is performing very poorly this morning and its solution has been completely disregarded. Meanwhile, the 12z NAM seems to have at least a reasonable handle on the situation, showing storms developing by early afternoon near I-55, then shifting further east and south later in the day. Will continue to monitor stability parameters to see if projected 1500 to 2500J/kg CAPEs can be realized. If the airmass destabilizes as predicted, increasing shear values will help storms organize and potentially produce large hail and damaging winds this afternoon into this evening. Am still concerned about the threat for heavy rainfall across the E/SE CWA tonight as favorable jet dynamics produce enhanced synoptic lift along/ahead of approaching cold front. As storms become parallel to upper flow, training appears likely tonight along/south of a Danville to Jacksonville line. Latest NAM continues to put down some hefty rainfall totals across this area. && .SHORT TERM...(Today and tonight) ISSUED AT 355 AM CDT MON SEP 1 2014 Shortwave trough axis approaching Illinois from the west this morning bringing a line of thunderstorms to the region. Trends this morning are for the line splitting into to intense lines...one grazing Knox, Peoria, Stark county and likely Marshall and Woodford as it continues this morning. Have reports of pea-sized hail and wind gusts 30-40 mph with the more intense storm cells. The intense activity looks like it will have a break through central IL in the early morning once this initial activity shifts east-northeastward. Isolated thunderstorms will likely develop throughout the CWA during the morning...however daytime heating will likely be necessary to bring CAPE values up to 1500-2500 J/KG range to bring a better chance for severe storms when combined with 30-50 kt bulk shear values also shifting into central Illinois. Large hail and severe wind gusts will be a threat with the stronger storms this afternoon...and have continued mention of severe hail and heavy rain in forecast grids beginning at 3 pm this afternoon...continuing through around midnight. Heavy rain will continue through the night as a potent and moist low-level jet continues to push through the CWA...along with lift associated with the progressive trough and cold frontal boundary. && .LONG TERM...(Tuesday through Sunday) ISSUED AT 355 AM CDT MON SEP 1 2014 00Z models have trended slower with frontal boundary pushing into southeast IL Tue especially the NAM model and have increase pops to likely se of I-70 Tue morning. NAM model may be overdoing qpf amounts Tue morning over southeast IL but models have trended higher with qpf amounts with precipitable water values of 1.5-2 inches from 12-15Z Tue and have increased qpf amounts to around a quarter inch in southeast IL. IL river valley should be dry Tue and chances of showers and thunderstorms will diminish from nw to se during Tue afternoon. Highs 82-88F Tue and still rather humid especially in southeast IL with dewpoints 70-75F while dewpoints lower into mid 60s over IL river valley. Dry conditions return across area Tue night with frontal boundary dropping south of area. Lows in the low to mid 60s Tue night. Models show frontal boundary starting to lift back north especially over MS river valley and MO on Wed and have kept 20-30% chance of showers and thunderstorms sw areas by Wed afternoon with ne areas staying dry Wed. Warm highs in the mid to upper 80s Wed and model guidance has trended upward in high temps Wed. Dewpoints elevate during day Wed into upper 60s and lower 70s Wed afternoon. Convection chances appear highest over northern IL Wed night closer to short waves tracking into WI/northern IL and eventually eastward into lower MI and northern IN. Have areas south of I-72 dry Wed night. Thu and Fri still appear to be back into the heat and humidity with highs in the upper 80s and lower 90s and dewpoints peaking in the low to mid 70s giving afternoon heat indices of upper 90s to lower 100s especially Thu afternoon and in southeast IL Friday afternoon. A 593 dm 500 mb high pressure ridge over the southeast states builds the heat into central/southeast IL late this work week. Most of our area should be dry Thu and Thu night with just slight chance of convection Thu afternoon mainly over the Wabash river valley and nw of IL river Thu night. Models have trended faster with cold front dropping se through central IL Friday and thru southeast IL Fri evening. Have increased pops Friday and also trending cooler with temps and dewpoints during the weekend as 1025 mb high pressure settles into the Great Lakes region. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 1248 PM CDT MON SEP 1 2014 Convective development/evolution remains in question, as previous outflow boundary has pushed east of the I-55 corridor early this afternoon. Most model solutions are keeping central Illinois largely dry through the afternoon, with thunderstorms developing/increasing after dark across the south. Based on 12z NAM and latest HRRR, it appears the axis of heavy rain will be focused along the I-70 corridor between 05z and 12z. As such, have kept both KPIA and KBMI dry through the entire 18z TAF period. Further south, have introduced -RA with VCTS at the remaining terminals after 05/06z, thinking they may be on the northern fringe of the low-level jet enhanced precip area overnight. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...ONTON LONG TERM...07 AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1115 AM CDT MON SEP 1 2014 .DISCUSSION... 340 AM CDT ENTERING SEPTEMBER AND METEOROLOGICAL AUTUMN WE STILL FIND THE FORECAST CHALLENGES TO BE MORE SUMMER-LIKE...AT LEAST EARLY ON IN THE FORECAST. THAT IS STORM AND HEAVY RAIN POTENTIAL TODAY AND TONIGHT...THEN STORM CHANCES WEDNESDAY NIGHT AND FRIDAY WHICH SANDWICH A POSSIBLE 90 PLUS DEGREE DAY ON THURSDAY. LESS BUT STILL SOME TIME WAS SPENT ON THE FINAL CHALLENGE OF HOW MUCH OF A COOL DOWN OCCURS THE FIRST FULL WEEKEND OF THIS NEW METEOROLOGICAL SEASON. SYNOPSIS... A LONG WAVE TROUGH EXTENDING SOUTHWARD THROUGH CANADA INTO THE NORTH CENTRAL U.S. HAS A VERY PROGRESSIVE SHORT WAVE FEATURE MOVING THROUGH ITS SOUTHERN BASE. THIS IS SPEEDING EAST-NORTHEAST ACROSS IA EARLY THIS MORNING. A SURFACE COLD FRONT MOVING EAST LAGS THIS SHORT WAVE...EXTENDING FROM NORTHERN MN THROUGH THE TX PANHANDLE EARLY THIS MORNING...WITH MULTIPLE SURFACE WAVES IN THE 1003MB NEIGHBORHOOD ALONG IT. NORTHWEST SURFACE FLOW BEHIND THIS FRONT IS NOT PARTICULARLY STRONG SO THIS FRONT WILL CONTINUE TO BE A SLOW- MOVER TODAY...NOT EXPECTED TO ENTER THE FORECAST AREA UNTIL THIS EVE. BEING WITHIN A WARM SECTOR UNDER QUICKENING UPPER/MID-LEVEL FLOW PRESENTS THE STORM CHANCES THESE 24 HOURS. THIS MORNING... A LOOSELY DEFINED MCS MOVING EASTWARD INTO NORTHWEST IL EARLY THIS MORNING WANED CONSIDERABLY WITH WARMING CLOUD TOPS AND OUTFLOW EXTENDING WELL AHEAD OF IT. SEEING AN UPTICK ACROSS WEST CENTRAL IL LIKELY ASSOCIATED WITH LIFT OF THE AFOREMENTIONED PROGRESSIVE SHORT WAVE. HIGH RESOLUTION MODELS GREATLY VARY ON WHAT WILL HAPPEN EVEN JUST A FEW HOURS OUT...BUT WOULD EXPECT SYNOPTICALLY TO SEE SOME CONVECTION EVOLVE INTO THE FORECAST AREA THIS MORNING...POSSIBLY ONLY THE WESTERN/SOUTHWESTERN AREA BUT STILL CANT RULE OUT SCATTERED ACTIVITY MOVING EASTWARD THROUGH THE ENTIRE AREA INCLUDING CHICAGO DURING MID/LATE MORNING. DESPITE A FAIRLY STRONG LOW-LEVEL JET INTO ANY ACTIVITY...THE CONTINUED BROAD AREA OF STORMS ACROSS EASTERN KS INTO WEST/SOUTHWEST MO THROUGH EARLY TO MID MORNING SHOULD LESSEN MOISTURE TRANSPORT AND THUS ABILITY TO REALIZE STEEP LAPSE RATES ALOFT FOR MORE ROBUST ACTIVITY...AND MAYBE EVEN THUNDER IN GENERAL NORTH OF INTERSTATE 80. THIS AFTERNOON AND TONIGHT... DESPITE THIS BEING IN THE FIRST 12 HOURS OF THE FORECAST...DUE TO INFLUENCE OF MORNING STORMS AND LARGE MODEL DIFFERENCES...CONFIDENCE ON SPECIFICS IN THESE PERIODS REMAIN LOW. THERE SHOULD BE SOME FORM OF OUTFLOW BOUNDARY OR BOUNDARIES FROM MORNING ACTIVITY/CLOUD COVER THAT LINGER INTO THE FORECAST AREA INTO THE AFTERNOON...MOST FAVORED SOUTH OF INTERSTATE 80. AS WARMING AND DESTABILIZATION OCCURS WITH DEW POINTS AROUND 70F...COULD SEE SCATTERED ACTIVITY DEVELOP NEAR ANY SUCH BOUNDARIES DURING THE MID TO LATE AFTERNOON. THE SECOND UPPER WAVE ACROSS WESTERN WY THIS MORNING WILL BEGIN TO APPROACH THE REGION AS WELL BY LATE IN THE DAY...WITH FORCING FROM THIS POSSIBLY AIDING IN SCATTERED STORM DEVELOPMENT ACROSS MUCH OF THE REGION. EVEN EARLY THIS MORNING THERE ARE A HANDFUL OF STORMS ACROSS THE UPPER MIDWEST NOT LINKED TO ANY SPECIFIC SURFACE FEATURE. INCREASING DEEP LAYER SHEAR OF 35 TO 50 KT WILL SUPPORT ISOLATED TO SCATTERED SEVERE DISCRETE STORMS IN THE REGION. WHILE IT REMAINS DIFFICULT TO PINPOINT TIMING...IT WOULD SEEM THE GREATEST COVERAGE IN REDEVELOPING STORMS THIS EVENING WOULD BE IN THE SOUTHERN FORECAST AREA WHERE AFOREMENTIONED BOUNDARY MAY OCCUR AND MODEST SOUTHWEST 850-925MB FLOW AND MOISTURE TRANSPORT REMAINS. AS THE AREA BECOMES UNDER A RIGHT ENTRANCE REGION TO THE UPPER JET...DO EXPECT INCREASING ASCENT TONIGHT IN THE REGION FOR MORE ROBUST CONVECTION AND POTENTIAL SEVERE AND HEAVY RAIN THREATS. RIGHT NOW A GUIDANCE OVERLAP WOULD INDICATE THE FAR SOUTHEAST FORECAST AREA IS MOST FAVORED FOR THIS. PRECIPITABLE WATERS AROUND TWO INCHES AND STORM MOTIONS NEARLY PARALLEL TO THE UPPER AND MID LEVEL FLOW WILL PRESENT HEAVY RAIN THREATS IN THE GENERAL CENTRAL TO SOUTHERN IL INTO IN REGIONS...BUT AGAIN AT THIS TIME CONFIDENCE VARIES ON PLACEMENT. BECAUSE OF THAT WILL CONTINUE WITH THE HYDROLOGIC OUTLOOK /ESF/ FOR THE AREAS HIT HARD ON SATURDAY NIGHT WITH HEAVY RAINFALL. TUESDAY AND WEDNESDAY... THE FRONT SHOULD CLEAR THE FORECAST AREA SOMETIME TUESDAY MORNING. WHILE DRY AIR ADVECTION WILL OCCUR...LIMITED CONVERGENCE REMAINS IN THE SOUTHEAST FORECAST AREA FOR POSSIBLY A STORM OR TWO TUESDAY BUT IT LOOKS TO BE A LOW CHANCE. TEMPERATURES ONLY COOL SLIGHTLY AS HIGH PRESSURE QUICKLY MOVES ATOP THE AREA TUESDAY NIGHT AND THEN EASTWARD. WEDNESDAY NIGHT THROUGH FRIDAY... WARM AIR ADVECTION AND A RAPID PRECIPITABLE WATER INCREASE IS FORECAST WEDNESDAY NIGHT ON ALL GUIDANCE. FEEL THAT MODELS MAY BE UNDER-DOING THE STORM CHANCES GIVEN FORECAST PROFILES OF STEEPENING LAPSE RATES WITHIN A RAPIDLY MOISTENING COLUMN...AT LEAST IN THE WESTERN FORECAST AREA. SO HAVE INCREASED POPS IN THAT AREA. AS FOR THURSDAY...HAVE GONE DRY IN MANY AREAS COLLABORATING AND UNDERCUTTING A MODEL BLEND OF POPS. THE SYNOPTIC PATTERN FAVORS A HOT DAY AND BARRING ANY STRATUS ISSUES WITH WEDNESDAY NIGHTS WARM AIR ADVECTION AND POSSIBLE PRECIP...SHOULD SEE THE 90 DEGREE MARK REACHED OR EXCEEDED ACROSS A GOOD PART OF THE FORECAST AREA BASED ON STRONG SOUTHWEST FLOW AND FORECAST 850MB AND 925MB TEMPERATURES COMPARED TO CLIMATOLOGY. FOR NOW HAVE KEPT THE NORTH A LITTLE BELOW THAT WITH THE POSSIBILITY OF MORNING CLOUDS. THE SYSTEM COLD FRONT IS PRESENTLY FORECAST BY THE EC AND THE GFS TO COME THROUGH THE AREA SOMETIME ON FRIDAY WHICH WOULD BRING STORM CHANCES WITH IT...AS WELL AS FLOW TURNING OFF THE LAKE BEHIND ITS PASSAGE. BEYOND... NO CHANGES MADE TO THIS WEEKEND WHERE HIGHS LOOK TO BE AROUND 70 WITH DRY CONDITIONS BEHIND THE AFOREMENTIONED FRONT. HIGH PRESSURE AROUND 1023MB IS FORECAST BY A BLEND OF GUIDANCE. GIVEN THE 925MB TEMPERATURES FORECAST IF THAT HIGH IS CENTERED OVER THE FORECAST AREA SOMETIME SUNDAY OR MONDAY NIGHTS /7TH OR 8TH/...LOWS IN OUTLYING AREAS WOULD LIKELY BE IN THE 40S. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * MVFR CIGS/VSBYS IN THE SHORT TERM WITH SHRA. * CEILING TRENDS THROUGH THE AFTERNOON...MVFR POSSIBLE. * WINDS GRADUALLY VEERING MORE WESTERLY THEN NORTHWEST LATE. * VCSH AGAIN THIS EVENING...ISOLATED TSRA NOT OUT OF THE QUESTION. LENNING //DISCUSSION...UPDATED 12Z... CONVECTIVE CHANCES AND TIMING CONTINUE TO BE THE PRIMARY WEATHER CONCERN AND FOCUS FOR THE AREA TODAY. THE OVERNIGHT THUNDERSTORM ACTIVITY TO OUR WEST HAS DISSIPATED AS IT MOVED ACROSS NORTHERN ILLINOIS. HOWEVER...ITS EFFECTS ON THE SURFACE WINDS AND CIGS REMAIN. AS SUCH...IT APPEARS THAT A SHORT PERIOD OF LOW MVFR CIGS AND AN EAST-SOUTHEASTERLY WIND COMPONENT ARE EXPECTED THROUGH AROUND 14 UTC THIS MORNING BEFORE THE WINDS REVERT BACK OUT OF THE SOUTHWEST AND BECOME A BIT GUSTY BY MID TO LATE MORNING. UNCERTAINTY REMAINS SOMEWHAT HIGH IN WHETHER OR NOT ANY CONVECTIVE ACTIVITY WILL IMPACT THE TERMINALS TODAY. OVERALL IT APPEARS THE BEST CHANCES IN THE NEAR TERM WILL BE ROUGHLY BETWEEN 16 AND 19 UTC AS A WEATHER DISTURBANCE ACROSS NORTHEASTERN MISSOURI SHIFTS EASTWARD OVER THE AREA. THIS COULD LEAD TO SOME DEVELOPMENT NEAR...OR JUST SOUTH OF THE TERMINALS DURING THIS PERIOD. THEREAFTER...IT ALSO APPEARS THERE MAY BE ANOTHER CHANCE FOR SOME SCT STORMS THIS EVENING AFTER 23 UTC AS ANOTHER STOUT UPPER LEVEL DISTURBANCE MOVES OVER NORTHERN ILLINOIS AS A COLD FRONT APPROACHES. TIMING AT THIS JUNCTURE REMAINS VERY DIFFICULT TO PIN DOWN...AND THIS WILL NEED TO BE IRONED OUT AS WE GET A BETTER HANDEL ON TRENDS THROUGH THE DAY. EITHER WAY...THERE WILL LIKELY BE AREAS OF CONVECTIVE ACTIVITY THIS AFTERNOON AND TONIGHT SOUTH OF THE TERMINALS. KJB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM TO HIGH CONFIDENCE OF BRIEF MVFR CIGS/VSBYS IN THE SHORT TERM WITH SHRA...THEN IMPROVING. * MEDIUM TO HIGH CONFIDENCE IN WINDS...AND HIGH CONFIDENCE THEY REMAIN FROM A WESTERLY COMPONENT. * MEDIUM TO LOW CONFIDENCE OF SHRA AGAIN THIS EVENING...AND LOW CONFIDENCE REGARDING ISOLATED TSRA. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH THURSDAY...PREDOMINANTLY VFR. FRIDAY...CHANCE OF SHRA/TSRA. SATURDAY AND SUNDAY...PREDOMINANTLY VFR. KJB && .MARINE... 232 AM CDT IT LOOKS TO BE AN ACTIVE WEATHER DAY ACROSS THE LAKE...WITH STOUT SOUTHERLY WINDS LAKE-WIDE...AND THE THREAT FOR SOME STRONG TO SEVERE THUNDERSTORMS ACROSS SOUTHERN LAKE MICHIGAN. THESE STRONG SOUTHERLY WINDS WILL RESULT IN WINDS AROUND 25 KT AND THE ONGOING SMALL CRAFT ADVISORY STILL APPEARS GOOD. THE SURFACE LOW...RESPONSIBLE FOR THESE STRONG SOUTHERLY WINDS TODAY...WILL SHIFT ACROSS ONTARIO...AND TO NEAR JAMES BAY BY THIS EVENING WHILE DEEPENING TO AROUND 29.2 INCHES. AS THIS OCCURS...AN ASSOCIATED COLD FRONT WILL BE DRAWN EASTWARD ACROSS THE LAKE BY EARLY TUESDAY MORNING. WINDS WILL BECOME WESTERLY AND ABATE SIGNIFICANTLY WITH THE PASSAGE OF THIS FRONT. ANOTHER PERIOD OF STRONGER SOUTHERLY WINDS LOOKS TO SET UP AGAIN WEDNESDAY NIGHT AND THURSDAY AS ANOTHER POTENT AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS ONTARIO. WINDS SPEEDS COULD AGAIN BE AROUND 25 KT OUT OF THE SOUTH DURING THIS PERIOD. ANOTHER STRONGER COLD FRONT LOOKS TO SHIFT DOWN THE LAKE IN THE WAKE OF THIS LOW LATE FRIDAY AND THIS COULD SET THE STAGE FOR A DECENT NORTHERLY WIND EVENT ACROSS THE LAKE AS A STOUT AREA OF HIGH PRESSURE QUICKLY BUILDS EASTWARD ACROSS THE UPPER MIDWEST. STRONG NORTHERLY WINDS OF 25 TO 30 KT APPEAR QUITE POSSIBLE IN THE WAKE OF THIS COLD FRONT FRIDAY NIGHT INTO SATURDAY...WHICH WOULD ALSO RESULT IN LARGE WAVES IN EXCESS OF 5 FEET ACROSS SOUTHERN LAKE MICHIGAN INTO NEXT WEEKEND. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1001 AM CDT Mon Sep 1 2014 .UPDATE... ISSUED AT 1001 AM CDT MON SEP 1 2014 Line of strong to severe thunderstorms tracked across Iowa last night, then rapidly dissipated as it pushed toward the Mississippi River early this morning. Outflow boundary from this dying convection is currently approaching the I-55 corridor as evidenced by westerly winds across all sites in the Illinois River Valley. Think this outflow will eventually serve as the primary focus for additional thunderstorm development later today. Still some question as to exactly where the boundary will lay out and when convection will fire, but the latest thinking from SPC has pushed the best severe weather risk much further southeast, generally along/south of a Danville to Jacksonville line. HRRR is performing very poorly this morning and its solution has been completely disregarded. Meanwhile, the 12z NAM seems to have at least a reasonable handle on the situation, showing storms developing by early afternoon near I-55, then shifting further east and south later in the day. Will continue to monitor stability parameters to see if projected 1500 to 2500J/kg CAPEs can be realized. If the airmass destabilizes as predicted, increasing shear values will help storms organize and potentially produce large hail and damaging winds this afternoon into this evening. Am still concerned about the threat for heavy rainfall across the E/SE CWA tonight as favorable jet dynamics produce enhanced synoptic lift along/ahead of approaching cold front. As storms become parallel to upper flow, training appears likely tonight along/south of a Danville to Jacksonville line. Latest NAM continues to put down some hefty rainfall totals across this area. && .SHORT TERM...(Today and tonight) ISSUED AT 355 AM CDT MON SEP 1 2014 Shortwave trough axis approaching Illinois from the west this morning bringing a line of thunderstorms to the region. Trends this morning are for the line splitting into to intense lines...one grazing Knox, Peoria, Stark county and likely Marshall and Woodford as it continues this morning. Have reports of pea-sized hail and wind gusts 30-40 mph with the more intense storm cells. The intense activity looks like it will have a break through central IL in the early morning once this initial activity shifts east-northeastward. Isolated thunderstorms will likely develop throughout the CWA during the morning...however daytime heating will likely be necessary to bring CAPE values up to 1500-2500 J/KG range to bring a better chance for severe storms when combined with 30-50 kt bulk shear values also shifting into central Illinois. Large hail and severe wind gusts will be a threat with the stronger storms this afternoon...and have continued mention of severe hail and heavy rain in forecast grids beginning at 3 pm this afternoon...continuing through around midnight. Heavy rain will continue through the night as a potent and moist low-level jet continues to push through the CWA...along with lift associated with the progressive trough and cold frontal boundary. && .LONG TERM...(Tuesday through Sunday) ISSUED AT 355 AM CDT MON SEP 1 2014 00Z models have trended slower with frontal boundary pushing into southeast IL Tue especially the NAM model and have increase pops to likely se of I-70 Tue morning. NAM model may be overdoing qpf amounts Tue morning over southeast IL but models have trended higher with qpf amounts with precipitable water values of 1.5-2 inches from 12-15Z Tue and have increased qpf amounts to around a quarter inch in southeast IL. IL river valley should be dry Tue and chances of showers and thunderstorms will diminish from nw to se during Tue afternoon. Highs 82-88F Tue and still rather humid especially in southeast IL with dewpoints 70-75F while dewpoints lower into mid 60s over IL river valley. Dry conditions return across area Tue night with frontal boundary dropping south of area. Lows in the low to mid 60s Tue night. Models show frontal boundary starting to lift back north especially over MS river valley and MO on Wed and have kept 20-30% chance of showers and thunderstorms sw areas by Wed afternoon with ne areas staying dry Wed. Warm highs in the mid to upper 80s Wed and model guidance has trended upward in high temps Wed. Dewpoints elevate during day Wed into upper 60s and lower 70s Wed afternoon. Convection chances appear highest over northern IL Wed night closer to short waves tracking into WI/northern IL and eventually eastward into lower MI and northern IN. Have areas south of I-72 dry Wed night. Thu and Fri still appear to be back into the heat and humidity with highs in the upper 80s and lower 90s and dewpoints peaking in the low to mid 70s giving afternoon heat indices of upper 90s to lower 100s especially Thu afternoon and in southeast IL Friday afternoon. A 593 dm 500 mb high pressure ridge over the southeast states builds the heat into central/southeast IL late this work week. Most of our area should be dry Thu and Thu night with just slight chance of convection Thu afternoon mainly over the Wabash river valley and nw of IL river Thu night. Models have trended faster with cold front dropping se through central IL Friday and thru southeast IL Fri evening. Have increased pops Friday and also trending cooler with temps and dewpoints during the weekend as 1025 mb high pressure settles into the Great Lakes region. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 708 AM CDT MON SEP 1 2014 A mix of IFR and MVFR ceilings and southerly winds generally 8-12 kts this morning across central Illinois as a cold front approaches from the west. A line of thunderstorm activity ahead of the front continues to approach, however activity is generally weak along portions of the line headed for central IL. As surface heating takes place, thunderstorm development will intensify through the early afternoon as daytime heating initiates and the most intense portions of the storm system move into the region. Some storms may become severe with hail and severe wind gusts this afternoon and evening. Thunderstorm activity will shift toward southeast portions of the state tonight. As no clear features exist at this point to pinpoint timing of thunderstorms, have broad-brushed thunderstorm activity with predominant -SHRA and VCTS in TAFs starting 16Z- 17Z...then diminished VCTS/VCSH mention from northwest to southeast overnight. Doubtful MVFR ceilings will dissipate significantly through the day so have kept cigs no better than bkn020-025 for the next 24 hours. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...ONTON LONG TERM...07 AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1247 AM CDT MON SEP 1 2014 .UPDATE... ISSUED AT 820 PM CDT SUN AUG 31 2014 EVENING UPDATE FOR TIMING/INTENSITY OF THUNDERSTORMS INTO THE FORECAST AREA LATE TONIGHT INTO MONDAY MORNING. LATEST RADAR TRENDS...MODELED WELL BY THE HRRR/RAP...INDICATE STORMS PUSHING INTO THE WESTERN FRINGE OF THE FORECAST AREA NEAR AND AFTER 11 PM CDT. HAVE UPDATED FORECAST GRIDS TO ADJUST TIMING AND BRING HIGHER POPS IN EARLIER. DESPITE THE COOLING BOUNDARY LAYER...THE COMPLEX MOVING INTO CENTRAL IOWA MAY BE ABLE TO SUSTAIN A DAMAGING WIND THREAT UNTIL 2 OR 3 AM CDT. CONVECTION STILL EXPECTED TO WEAKEN OVERNIGHT AND DECREASE IN COVERAGE NEAR AND EAST OF THE MISSISSIPPI RIVER. HAVE UPDATED THE HAZARDOUS WEATHER OUTLOOK TO REFLECT FORECAST CHANGES. && .SYNOPSIS... ISSUED AT 313 PM CDT SUN AUG 31 2014 A WARM...MID SUMMER-LIKE DAY IS FOUND OVER OUR CWA TODAY AS WE REMAIN WELL EAST OF THE COLD FRONT APPROACHING IOWA THIS AFTERNOON. THE COLD FRONT IS SLOWLY MOVING EAST...AND HAS ALREADY SPAWNED A FEW HIGH BASED THUNDERSTORMS FROM SOUTHERN MN TO FAR EASTERN NE. TEMPERATURES WITH FULL SUN TODAY HAVE REACHED THE MID 80S AS OF 2 PM...AND APPEAR SET FOR HIGHS IN THE MID TO UPPER 80S BEFORE CLOUDS INTERRUPT THE HEATING LATER THIS AFTERNOON. SURFACE BASED STORMS REMAIN CAPPED FOR NOW...THOUGH CAPE VALUES ARE SHOWN ON RAP DATA TO BE 2000 TO 4000 J/KG. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 313 PM CDT SUN AUG 31 2014 THERE IS LITTLE DOUBT THERE WILL BE AN IMPRESSIVE CONVECTIVE EVENT TONIGHT. THERE IS PLENTY OF DOUBT THAT IT WILL STRONGLY AFFECT MORE THAN JUST THE WESTERN MOST PORTION OF OUR CWA. THE SLOW MOVING FRONT SHOULD BE ENOUGH TO FOCUS STORMS WITH PLENTY OF CAPE AND MOISTURE AVAILABLE TO THE WEST...LIKELY NEAR THE MISSOURI RIVER. THEY SHOULD MOVE EAST...SLOWLY. THIS PLACES THE WEAKENING PHASE OF THE COMPLEX INTO EASTERN IOWA BETWEEN MIDNIGHT AND 9 AM MONDAY. THIS POOR DIURNAL TIMING COMBINED WITH LESS THAN IDEAL MOISTURE TRANSPORT DURING THAT TIME FRAME SUGGESTS BOTH INTENSITY AND COVERAGE OF STORMS WILL BE ON THE WANE IN THAT PERIOD. I HAVE CONFINED HIGH POPS TO ONLY THE WESTERN CWA LATE TONIGHT...AND LOWERED TO CHANCE FOR MONDAY MORNING SINCE MOST MODELS SUGGEST A FRAGMENTED LINE...AND THAT SEEMS MOST LIKELY TO ME AS WELL. QPF SHOULD BE IMPRESSIVE TO THE WEST...BUT MAY BE INSIGNIFICANT IN OUR CWA...GENERALLY 0.25 OR LESS IN ALL BE THE FAR WEST...WHERE 0.5 TO 1.0 IS POSSIBLE. MONDAY WILL SEE FAR BETTER DYNAMICS...THUS THE SPC OUTLOOK FOR SEVERE WEATHER. HOWEVER...THE CONVERGENT OUTFLOW BOUNDARY WILL LIKELY BE WELL IN ADVANCE OF THE COLD FRONT...WHICH SHOULD ALSO DEFLECT THE STRONGEST HEATING WELL EAST OF THE CWA AS WELL. THUS...THE WEAKENING CONVECTIVE DEBRIS SHOULD INHIBIT OUR MONDAY SEVERE POTENTIAL...AS WELL AS WIDESPREAD RAIN POTENTIAL AGAIN. SURE SEEMS THIS EVENT SHOULD PRODUCE THE MAJORITY OF ITS RAIN WEST AND SOUTHEAST OF OUR CWA. ERVIN .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 313 PM CDT SUN AUG 31 2014 THE FRONT WILL CLEAR THE SOUTHEAST HALF OF THE AREA LATE MONDAY EVENING. THE SOUTHEAST HALF OF THE AREA SHOULD SEE PRECIPITATION ONGOING AT SUNSET THAT ENDS FROM NORTHWEST TO SOUTHEAST AFTER MIDNIGHT. DRIER AIR MOVING INTO THE AREA SHOULD RESULT IN LOWS NEAR OR SLIGHTLY BELOW NORMAL BY SUNRISE TUESDAY. TUESDAY/TUESDAY NIGHT DRY CONDITIONS ARE EXPECTED AS HIGH PRESSURE MOVES THROUGH THE MIDWEST. TEMPERATURES SHOULD BE CLOSE TO NORMAL. WEDNESDAY MORNING LOOKS TO BE DRY ACROSS THE AREA AS THE HIGH MOVES TOWARD THE EAST COAST. A WEAK DISTURBANCE WILL MOVE THROUGH THE AREA WEDNESDAY AFTERNOON. THE OVERALL FORCING IS NOT STRONG AND MOISTURE AVAILABILITY IS IN QUESTION. IF PRECIPITATION DOES OCCUR IT WOULD BE ISOLATED IN NATURE WITH THE SOUTH HALF BEING FAVORED. WEDNESDAY NIGHT ON... THE MODEL CONSENSUS HAS SLIGHT CHANCE TO CHANCE POPS IN EACH 12 HR PERIOD FROM WEDNESDAY NIGHT THROUGH SATURDAY. THERE IS A WEAK DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT/THURSDAY. MOISTURE AVAILABILITY WILL BE ON THE INCREASE BUT THE OVERALL FORCING IS NOT STRONG. THE POSSIBILITY DOES EXIST THERE WILL BE PERIODS OF DRY WEATHER WEDNESDAY NIGHT/THURSDAY. THE MODELS DIFFER SOMEWHAT ON THE TIMING BUT AGREE THAT ANOTHER COLD FRONT WILL MOVE THROUGH THE AREA IN THE THURSDAY NIGHT THROUGH FRIDAY NIGHT TIME FRAME. SEVERAL MODELS ARE PUSHING A SIGNIFICANT HIGH INTO THE WESTERN GREAT LAKES ON SATURDAY. THE CURRENT MODEL CONSENSUS HAS SLIGHT CHANCE POPS ACROSS THE SOUTH QUARTER OF THE AREA BUT THE OVERALL TREND IS SUGGESTING DECREASING PRECIPITATION CHANCES. SATURDAY NIGHT THROUGH SUNDAY THE MODEL CONSENSUS HAS DRY CONDITIONS WITH HIGH PRESSURE OVER THE GREAT LAKES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1237 AM CDT MON SEP 1 2014 LINEAR MESOSCALE CONVECTIVE SYSTEM WILL CONTINUE TO MOVE ACROSS THE REGION OVERNIGHT WHILE SLOWLY WEAKENING. GUSTY WINDS WITH MVFR TO LOCALLY IFR CONDITIONS EXPECTED IN THE STORMS... WITH AN ISOLATED SEVERE WIND GUST TO 60 MPH POSSIBLE NEAR TO SOUTHWEST OF QUAD CITIES. WAKE LOW FOLLOWING MAY RESULT IN GUSTY EAST/SOUTHEAST WINDS DEVELOPING INTO EASTERN IA ESPECIALLY AT KCID TERMINAL. COLD FRONT ANTICIPATED TO PASS THROUGH THE TERMINALS THIS AFTERNOON. REDEVELOPMENT OF SOME SHOWERS AND STORMS IS POSSIBLE AHEAD OF THE FRONT FAVORING KMLI AND KBRL...BUT NOT CONFIDENT TO INTRODUCE AT THIS TIME DUE TO POSSIBLE LINGERING DEBRIS CLOUDS FROM AM CONVECTION AND WEAK FRONTAL CONVERGENCE. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...RP KINNEY SYNOPSIS...ERVIN SHORT TERM...ERVIN LONG TERM...08 AVIATION...05
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
622 PM CDT TUE SEP 2 2014 ...UPDATE TO AVIATION... .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 344 PM CDT TUE SEP 2 2014 THE MID TO UPPER LEVEL FLOW HAS BECOME ZONAL IN THE WAKE OF THE MINOR SHORTWAVE TROUGH THAT TRAVERSED THE CENTRAL PLAINS MONDAY EVENING. THE EFFECTIVE FRONTAL BOUNDARY AFTER ALL OF THE NIGHTTIME CONVECTION WAS SITUATED ACROSS CENTRAL OKLAHOMA AND SOUTHERN ARKANSAS. SOUTH OF THIS FRONT, TEMPERATURES WERE ABOVE 90 AS OF 2 PM, BUT ON THE COOL SIDE OF THE FRONT, MOST READINGS WERE IN THE 70S TO LOWER 80S. LEE TROUGHING WILL DEVELOP TONIGHT AND WEDNESDAY IN RESPONSE TO THE ZONAL FLOW. LATE TONIGHT, WARMER MID LEVEL TEMPERATURES WILL SPREAD ACROSS SOUTHWEST KANSAS, CAPPING THE ELEVATED MOIST LAYER. THE NAM INDICATES THAT LOW LEVEL WINDS WILL BECOME SOUTHERLY AS THE WARM FRONT SHIFTS INTO NORTHERN KANSAS BY WEDNESDAY MORNING. HOWEVER, THE RAP SHOWS THE BOUNDARY STILL SITUATED ALONG THE KANSAS/OKLAHOMA BORDER AT 12Z. SINCE WE MAY MAINTAIN UPSLOPE SOUTHEASTERLY FLOW MOST OF THE NIGHT, I OPTED TO BRING THE LOW CLOUDS AND FOG BACK IN TOWARD 09Z. A MID LEVEL CLOUD DECK MAY DEVELOP AS THE LOW LEVEL JET DEVELOPS THIS EVENING AND AN ELEVATED THUNDERSTORM OR TWO CAN`T BE COMPLETELY RULED OUT OVER SOUTH CENTRAL KANSAS BEFORE THE STRONG CAPPING INVERSION DEVELOPS. ON WEDNESDAY, THE LEE TROUGH WILL BECOME ESTABLISHED ACROSS THE HIGH PLAINS, WITH A WEAK SURFACE DRYLINE SITUATED ACROSS FAR WESTERN KANSAS. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT LATE IN THE DAY. HIGH TEMPERATURES WILL BE IN THE MID TO HIGH 90S,WITH SOME READINGS CLOSE TO 100F. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 357 PM CDT TUE SEP 2 2014 A STRONG UPPER LEVEL SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE EASTWARD INTO THE NORTHERN PLAINS AND UPPER MIDWEST BY FRIDAY. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS WESTERN KANSAS AND THE CENTRAL PLAINS ON THURSDAY BRINGING THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS. THE STRONGEST MID AND UPPER LEVEL WINDS WILL BE IN NEBRASKA, SO NOT EXPECTING LOTS OF SEVERE WITH THE FRONT. CAPE VALUES AROUND 2000 J/KG WILL BE SUFFICIENT TO PRODUCE SOME SMALL HAIL AND STRONG WINDS AS THE COLD FRONT SWEEPS ACROSS WESTERN KANSAS TO NEAR DODGE CITY BY 7 PM THURSDAY AND THROUGH MEDICINE LODGE BY AROUND MIDNIGHT. HIGH TEMPERATURES WILL BE VERY WARM AHEAD OF THE COLD FRONT ON THURSDAY WITH LOW TO MID AND UPPER 90S FORECAST. HIGHS THEN COOL INTO THE 70S INTO FRIDAY WITH A CONTINUED CHANCE FOR MAINLY AFTERNOON THUNDERSTORMS BEHIND THE FRONT IN MOIST SURFACE UPSLOPE FLOW. BY MONDAY HIGHS WARM BACK INTO THE 80S AS THE COOL HIGH PRESSURE AREA MOVES EAST AND WARM SOUTHERLY WINDS INCREASE. MORE THUNDERSTORM CHANCES CONTINUE INTO TUESDAY WITH DISTURBANCES IN SOUTHWEST FLOW ALOFT AND UPPER JET. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 618 PM CDT TUE SEP 2 2014 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH LATE THIS EVENING. AREAS OF LOW LEVEL STRATUS ARE EXPECTED TO DEVELOP ACROSS PORTIONS OF CENTRAL AND SOUTHWEST KANSAS LATE TONIGHT AS A RESULT OF HIGH RELATIVE HUMDITY AND LIGHT SOUTHEAST UPSLOPE WINDS. IFR CIGS WILL BE POSSIBLE IN THE VICINITY OF ALL TAF SITES OVERNIGHT. THE POTENTIAL FOR FOG EXISTS AS WELL TOWARD DAYBREAK WEDNESDAY MORNING RESULTING IN POTENTIAL MVFR VSBYS IN THE VICINITY OF ALL TAF SITES. VFR CONDITIONS WILL RETURN BY MID DAY WEDNESDAY. SOUTHEASTERLY WINDS OF AROUND 5 TO 15KT TONIGHT WILL BECOME MORE SOUTHERLY LATE WEDNESDAY MORNING WHILE INCREASING TO AROUND 20 TO 30KT AS A LEE SIDE TROUGH STRENGTHENS ACROSS EASTERN COLORADO. && .PRELIMINARY POINT TEMPS/POPS... DDC 70 97 72 95 / 10 0 10 30 GCK 68 99 70 92 / 0 0 10 40 EHA 66 99 68 94 / 0 10 10 30 LBL 70 98 71 96 / 0 0 10 20 HYS 68 98 72 92 / 10 10 10 50 P28 72 97 74 97 / 30 10 10 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...FINCH LONG TERM...KRUSE AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
319 PM CDT Mon Sep 1 2014 .SHORT TERM...(This Evening through Tuesday) Issued at 319 PM CDT MON SEP 1 2014 Quick cyclonic upper flow remains in place with the core of last night`s wave already in the Great Lakes and another weaker wave coming into the High Plains per recent water vapor imagery. The cold front`s location is hard to nail down behind outflow from the overnight convection and weak pressure fields, but appears to be bisecting the local area from southwest to northeast. Lower cloud under a modest inversion has been rather prevalent today, keeping temps in the 70s. Modest convergence persists in east central Kansas this afternoon. With still some CIN remaining per RAP analysis, confirmed by recent visible satellite imagery, and the western upper wave staying well north, storm chances don`t look great, but will maintain some mention ahead of the front in east central Kansas, diminishing with time as weak high pressure continues to move across northern sections of the state. There are some breaks in the clouds to the south, and some increase in instability is anticipated for the next few hours. Deep layer is not very high in the weak low level wind fields, but hard to completely rule out with mixed layer CAPE likely rising to near 1500 J/kg. As the surface high builds in, winds should be rather light, and depending on cloud trends particularly with convection, a fairly good setup for radiational fog will be in place with cloudy skies and limited mixing today and low cloud scouring out following the recent heavy rain. Will go ahead with some patchy fog mention at this point and let later shifts watch trends. Storm chances continue to look like Tuesday but with the boundary again possibly not far south, will keep a small chance near it. Better mixing and insolation should yield highs back into the 80s. .LONG TERM...(Tuesday Night through Monday) Issued at 319 PM CDT MON SEP 1 2014 Models continue to show the potential for elevated thunderstorms and large hail Tuesday night. The one wrinkle is the NAM appears to be quite a bit stronger in magnitude for both the elevated instability and effective shear. There is still good theta-e advection along the nose of the low level jet as well as isentropic upglide, so I think there should be some storms over eastern KS. The question is whether they will be strong enough to produce severe hail. Have continued with a chance POP through the night and think the potential still exists for some severe storms. It just may be more marginal than the NAM would suggest. With the exception of some elevated precip possibly lingering through the morning Wednesday, the forecast should quiet down as the models keep the jet stream and synoptic scale energy north of the forecast through Thursday morning. By Thursday night, a frontal system is projected to begin moving into the area. There is some uncertainty in the timing of the frontal system as most solutions have trended faster with the front, the NAM being the fastest. For now I`ve not made many changes from the previous forecast thinking the front would move through mainly Friday and Friday evening with the higher chances for precip in these periods. However if the faster trend continues, the POPs may need to be pushed up in the forecast as well. Have continued to trend POPs down for Saturday and kept a dry forecast for Sunday with models showing surface ridging and relatively dryer air over KS. By Monday, there is some disagreement with the GFS and ECMWF in the amplification of an upper trough across the west. Because the GFS is the more amplified solution, it is quick to set up return flow with the potential for shortwaves within southwesterly flow aloft to pass near the area. Have taken a conservative approach with the forecast at this time and have introduced only a slight chance for precip on Monday until there is a little more agreement in solutions. Temps will remain quite warm Wednesday and Thursday as the models show the thermal ridge over portions of the state. Because of this have continued with highs in the 90s and lows from around 70 to the mid 70s. Cold air advection is expected to increase Thursday night as the front moves through the area. This should bring a cool down for the weekend with highs in the 70s and lows in the 50s to around 60. && .AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon) Issued at 1251 PM CDT MON SEP 1 2014 Appears convective concerns at TOP and FOE are somewhat lower than earlier expectations with persistent cloud keeping instability in check and area of convergence near passing boundary should be south before instability develops. Flow behind the boundary should clear skies somewhat allowing for decent radiational fog setup around 11Z. Have introduced MVFR BR at this point. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...65 LONG TERM...Wolters AVIATION...65
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1241 AM CDT Mon Sep 1 2014 .MESOSCALE DISCUSSION... Issued at 1240 AM CDT MON SEP 1 2014 The midnight through 3 AM period will continue to see at least some low end potential for marginally severe hail, and perhaps localized damaging wind gusts in the strongest storms able to downburst and transport momentum to the surface through the inversion (refer to recent SPC mesoscale discussion for more details). Aside from severe potential, the potential for flash flooding is increasing and could see additional warnings needed during the overnight hours. The outflow from the complex of storms has pushed into southern Kansas and stretched west-to-east while the upper trough and overall storm motion remains east southeast nearly parallel to the effective boundary. Moisture transport is very impressive into and over the frontal zone into central and east central Kansas while precipitable water values are running 2 to 2.2 inches according to RAP analysis. Dual-pol signatures have at times indicated very heavy rainfall rates to around 2" per hour with the heaviest activity and spotters have reported 15-20 minute periods with 1 to 1.5 inches of rain. The orientation of the front and storm motion suggests training of individual convective updrafts over the same areas from southern Dickinson through Morris, Lyon, Coffey, Anderson, southern Osage and southern Franklin counties. Dual-pol rain estimates as of midnight range from 4" in southern Dickinson county to 2.5" in Lyon county to 2" in Osage/Franklin counties. Given current trends and expectations, could end up seeing a broad swatch of 2 to 5" with locally 6+ inches possible. There are some indications that the rear edge of the convection is beginning to forward propagate toward the southeast which may help put a slightly faster end to the very heavy rain, but should continue to see development in advance of the upper trough axis and north of the outflow which could persist even behind any forward propagating segments. This heavy precip is also falling across the parts of the area that have been driest as of late, and can handle more water. However, the torrential rates alone will produce substantial runoff and may be sufficient for flash flooding even in the dry conditions. && ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Monday) Issued at 311 PM CDT SUN AUG 31 2014 Elevated activity has weakened and exited with good insolation in recent hours in weak subsidence allowing for a quick increase in winds and temps. 19Z surface observations suggest cold front from south central Nebraska to the SW corner of Kansas with some CU development on the north end. Recent water vapor imagery shows main upper wave pushing through southern Wyoming with convection in NC Colorado well behind the front. Overall setup continues to support a rather wet next 12-18 hours with cold front coming into northern and western areas overnight and upper trough following, with low level jet ramping up to around 60kts. Nearby 12Z observed precipitable water values were at to just above normal and continued advection of deeper moisture to the south will pump these values up. Still having some question on the early hours of the event. With surface low pressure in far SE Colorado, convergence along the front is not great, and the main upper trough well behind will not boost convergence until perhaps the daytime hours of Labor Day. Various higher resolution models are delayed with the convective initiation until around 23-0Z and could occur well into the CWA. Dewpoint depressions should remain in the 25-40F range for somewhat high cloud bases, but increasing low level wind fields will support strong low level helicity. Again, with the trough lagging, mid level winds are somewhat low to support a long-lived supercell, and wind and hail continue to the be the main severe weather concerns with ML CAPE of 2000-2500 J/kg and downdraft CAPE around 1200 J/kg currently analyzed. The high-res models are also similar with a secondary impulse of convection moving through in the late evening to overnight hours, perhaps via a sustained MCS from the current NC Colorado storms. This could track over northern areas again and bring an increased flooding concern, but with recent rains spotty at best, am not confident enough for a Watch. Convection should overall slowly clear from northwest to central areas overnight. Cold front still appears to sag south into southern areas for the afternoon hours of Labor Day. This again is not a clear-cut forecast with convective activity possibly affecting the location of the effective front. If at least some insolation can occur, cooling mid levels behind the upper trough should allow for moderate instability to again develop along and ahead of the effective front with plenty of shear to support severe storms. This time, upper winds will be stronger but weaker near the surface. .LONG TERM...(Monday Night through Sunday) Issued at 311 PM CDT SUN AUG 31 2014 For Monday night and Tuesday, have continued chances for precip as the expected outflow boundary from tonight`s convection gets hung up across southeast and south central KS. In general would anticipate POPs diminishing and becoming increasingly confined to far southern portions of the forecast area with time through the day Tuesday as the upper forcing moves east of the area and the low level jet veers to the southwest decreasing convergence along the front. Tuesday night may be more interesting in terms of strong to possibly severe thunderstorms. Most model guidance is pointing to strong theta-e advection overnight with good isentropic upglide. Additionally model forecast soundings have fairly steep mid level lapse rates with potentially 1000 to 1500 J/km of elevated instability. The NAM also shows around 30 KTS of effective bulk shear, so it is not out of the question that there could be some elevated storms capable of producing large hail. This activity may linger into Wednesday morning. After that the forecast is expecting a dry period through Thursday before models bring a frontal system into the area Thursday night through Friday night. Because of this boundary, have continued with some chance POPs for Thursday night through Friday. By Saturday, both the GFS and ECMWF build a surface ridge into the central plains with dryer air advecting in. Because of this, have trended POPs down for Saturday and kept Sunday dry. Temps are expected to remain warm through Thursday until the frontal system enters the region with chances for rain. The warmest days look to be Wednesday and Thursday as 850 temps warm to around 25C. Therefore have highs in the mid 90s with lows around 70 to the lower 70s. Temps should trend cooler by the weekend due to cold air advection behind the front. May see lows in the 50s with highs in the upper 70s to around 80 by Sunday. && .AVIATION...(For the 06Z TAFs through 06Z Monday Night) Issued at 1240 AM CDT MON SEP 1 2014 For the 06z TAFs, widespread showers and embedded thunderstorms will persist through the overnight hours into Monday morning. Some models are suggesting that areas of fog may develop before sunrise, especially near KTOP/KFOE. There is still uncertainty with regards to whether or not this will occur as winds may stay just high enough to diminish this threat, but went ahead and added a TEMPO group at this time and will continue to monitor the trends through the overnight hours. Expect this precipitation to shift south of the TAF sites during the morning hours with winds veering to the northwest and eventually north-northeast with the frontal passage. There is a chance for additional scattered thunderstorm develop late afternoon into early evening. However, the TAF sites may be near the northern edge of this precipitation development, so have only mentioned VCTS at this time due to the uncertainty in the exact location of these storms. Any storms that do develop near the TAF sites should shift southward by mid to late evening. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE...Barjenbruch SHORT TERM...65 LONG TERM...Wolters AVIATION...Hennecke
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1020 PM EDT TUE SEP 2 2014 .UPDATE... ISSUED AT 1020 PM EDT TUE SEP 2 2014 01Z SFC ANALYSIS SHOWS WAKE HIGH PRESSURE OVER MUCH OF EAST KENTUCKY TRAILING THE LINEAR MCS THAT PASSED THROUGH DURING THE EVENING WITH STRONG TO SEVERE STORMS THAT PRODUCED MAINLY DAMAGING WIND GUSTS. THIS SYSTEM HAS ESSENTIALLY WASHED OUT THE FRONT AND PUSHED IT MAINLY SOUTH AND EAST OF KENTUCKY. HOWEVER...THERE WILL STILL BE SOME SCATTERED SHOWERS AND PERHAPS A STRAY STORM AROUND THE FAR SOUTHEAST PORTION OF THE CWA INTO THE NIGHT. THE CLOUDS WILL GRADUALLY THIN AND CLEAR OVERNIGHT AND THIS WILL LIKELY SET THE STAGE FOR FOG FORMATION...BECOMING LOCALLY DENSE IN THE VALLEYS BY DAWN. HAVE INCLUDED THIS ALL IN THE GRIDS WITH THIS UPDATE. ALSO FINE TUNED THE TEMPS AND DEWPOINTS THROUGH MORNING PER THE LATEST OBS...TRENDS...AND GUIDANCE FROM THE CONSSHORT. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. A FRESHENED SET OF ZONES AND HWO HAVE BEEN SENT. UPDATE ISSUED AT 758 PM EDT TUE SEP 2 2014 THE MAIN LINE OF STORMS IS FINALLY MOVING INTO THE NEIGHBORING STATES. A SECONDARY TROUGH IS MOVING THROUGH THE BLUEGRASS AND APPEARS TO BE FALLING APART. THIS SYSTEM WILL CONTINUE TO MOVE TO THE SOUTH AND EAST AND WILL BE OUT OF THE AREA BY MORNING. HAD TO LOWER THE TEMPERATURES AS THEY DROPPED DOWN MUCH LOWER THAN EXPECTED AS THE LINE WENT THROUGH THE AREA. EXPECT FOG TO BE FORMING AS THE SYSTEM MOVES OUT. IT WILL BE PATCHY...BUT MAINLY DENSE. SOME ISOLATED SHOWERS MAY DEVELOP BEHIND THE MAIN SYSTEM TONIGHT...SO DID NOT IMMEDIATELY END THE PRECIPITATION CHANCES. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 343 PM EDT TUE SEP 2 2014 A LINE OF THUNDERSTORMS WITH HEAVY RAINS HAS FORMED ALONG AN OLD OUTFLOW BOUNDARY ACROSS THE MID SECTION OF EASTERN KENTUCKY. SOME OF THE STORMS HAVE BECOME NEAR SEVERE AND EXPECT SOME SEVERE STORM WARNINGS TO BE ISSUED DURING THE NEXT FEW HOURS. THE MAIN THREAT WILL BE WIND GUSTS. ANOTHER CONCERN IS THAT WITH UNIDIRECTIONAL FLOW AND HIGH PRECIPITABLE WATER...FLOODING CONCERNS WILL BE A REAL ISSUE THIS AFTERNOON AND EVENING...MAINLY IN THE SOUTHERN HALF OF EASTERN KENTUCKY AND ESPECIALLY ALONG THE OLD OUTFLOW BOUNDARY. EXPECT THE FRONT TO PUSH THE PRECIPITATION SOUTH OF THE AREA BY WEDNESDAY MORNING. IN GENERAL...THE HRRR AND RAP HAVE NOT BEEN DOING TOO WELL WITH THIS SYSTEM SO FAR. WEDNESDAY FIGURES TO BE A LITTLE MORE COMFORTABLE AS THE HUMIDITY WILL BE A LITTLE LOWER. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 301 PM EDT TUE SEP 2 2014 THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE FRONT FINALLY MOVES OUT OF THE AREA. TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 758 PM EDT TUE SEP 2 2014 THE THUNDERSTORMS HAVE MOVED OUT OF EASTERN KENTUCKY. SOME SHOWERS WILL BE POSSIBLE FOR A WHILE BEHIND THE SYSTEM. AS SOME CLEARING OCCURS...EXPECT SOME DENSE FOG TO FORM. THE FOG SHOULD BE DENSE AND EVENTUALLY BRING ALL THE TAF STATIONS TO VLIFR. EXPECT A RETURN TO VFR AFTER 14Z. FROM 00 TO 04Z...THE FOG MAY MOVE IN AND OUT OF AREAS...ESPECIALLY AT JKL AS SOME STRATUS MOVES OUT OF THE VALLEY AND MOVES ACROSS THE VSBY SENSOR. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JJ LONG TERM...AR AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
759 PM EDT TUE SEP 2 2014 .UPDATE... ISSUED AT 758 PM EDT TUE SEP 2 2014 THE MAIN LINE OF STORMS IS FINALLY MOVING INTO THE NEIGHBORING STATES. A SECONDARY TROUGH IS MOVING THROUGH THE BLUEGRASS AND APPEARS TO BE FALLING APART. THIS SYSTEM WILL CONTINUE TO MOVE TO THE SOUTH AND EAST AND WILL BE OUT OF THE AREA BY MORNING. HAD TO LOWER THE TEMPERATURES AS THEY DROPPED DOWN MUCH LOWER THAN EXPECTED AS THE LINE WENT THROUGH THE AREA. EXPECT FOG TO BE FORMING AS THE SYSTEM MOVES OUT. IT WILL BE PATCHY...BUT MAINLY DENSE. SOME ISOLATED SHOWERS MAY DEVELOP BEHIND THE MAIN SYSTEM TONIGHT...SO DID NOT IMMEDIATELY END THE PRECIPITATION CHANCES. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 343 PM EDT TUE SEP 2 2014 A LINE OF THUNDERSTORMS WITH HEAVY RAINS HAS FORMED ALONG AN OLD OUTFLOW BOUNDARY ACROSS THE MID SECTION OF EASTERN KENTUCKY. SOME OF THE STORMS HAVE BECOME NEAR SEVERE AND EXPECT SOME SEVERE STORM WARNINGS TO BE ISSUED DURING THE NEXT FEW HOURS. THE MAIN THREAT WILL BE WIND GUSTS. ANOTHER CONCERN IS THAT WITH UNIDIRECTIONAL FLOW AND HIGH PRECIPITABLE WATER...FLOODING CONCERNS WILL BE A REAL ISSUE THIS AFTERNOON AND EVENING...MAINLY IN THE SOUTHERN HALF OF EASTERN KENTUCKY AND ESPECIALLY ALONG THE OLD OUTFLOW BOUNDARY. EXPECT THE FRONT TO PUSH THE PRECIPITATION SOUTH OF THE AREA BY WEDNESDAY MORNING. IN GENERAL...THE HRRR AND RAP HAVE NOT BEEN DOING TOO WELL WITH THIS SYSTEM SO FAR. WEDNESDAY FIGURES TO BE A LITTLE MORE COMFORTABLE AS THE HUMIDITY WILL BE A LITTLE LOWER. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 301 PM EDT TUE SEP 2 2014 THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE FRONT FINALLY MOVES OUT OF THE AREA. TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 758 PM EDT TUE SEP 2 2014 THE THUNDERSTORMS HAVE MOVED OUT OF EASTERN KENTUCKY. SOME SHOWERS WILL BE POSSIBLE FOR A WHILE BEHIND THE SYSTEM. AS SOME CLEARING OCCURS...EXPECT SOME DENSE FOG TO FORM. THE FOG SHOULD BE DENSE AND EVENTUALLY BRING ALL THE TAF STATIONS TO VLIFR. EXPECT A RETURN TO VFR AFTER 14Z. FROM 00 TO 04Z...THE FOG MAY MOVE IN AND OUT OF AREAS...ESPECIALLY AT JKL AS SOME STRATUS MOVES OUT OF THE VALLEY AND MOVES ACROSS THE VSBY SENSOR. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJ SHORT TERM...JJ LONG TERM...AR AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
155 PM EDT MON SEP 1 2014 .UPDATE... ISSUED AT 155 PM EDT MON SEP 1 2014 UPDATED THE FORECAST TO BETTER TIME A LINE OF SCATTERED SHOWERS AND THUNDERSTORMS MOVING IN FROM THE WEST. THIS LINE IS OUT AHEAD OF THE COLD FRONT IN THE WARM AIR. THERE IS A BIT OF CURVATURE TO THE LINE OF HEAVIEST STORMS;...SO WILL BE WATCHING FOR SOME POTENTIALLY STRONG WIND GUSTS AS THE LINE GOES THROUGH. THE MERCER AND LINCOLN COUNTY MESONET SITES SAW WIND GUSTS OF 30 MPH AS THE LINE WENT THROUGH. CURRENT THINKING IS THE MAX GUSTS WILL STAY BELOW 40 MPH AND WILL BE IN THE 20 TO 30 MPH RANGE AS THE STORMS MOVE INTO EASTERN KENTUCKY. THE HEATING WILL BE A LITTLE BETTER...HOWEVER THE STORMS SEEM TO BE WEAKENING A LITTLE BIT. SO FAR...HAVE ONLY BEEN SEEING UP TO ONE QUARTER OF AN INCH OF RAIN FROM THE STORMS. HAVE A LITTLE CONCERN FOR PARTS OF EASTERN KENTUCKY THAT GOT HAMMERED LAST NIGHT FROM THE HEAVY RAIN...HOWEVER THESE STORMS HAVE BEEN QUITE PROGRESSIVE AND HAVE NOT YET SEEN ANY TRAINING OF THE ECHOES. UPDATE ISSUED AT 1048 AM EDT MON SEP 1 2014 UPDATED THE FORECAST TO INCLUDE ALL OF EASTERN KENTUCKY IN THE CHANCE OF PRECIPITATION TODAY BASED ON THE HIGH HRRR AND RUC MODEL OUTPUT AS WELL AS THE CURRENT RADAR. BASED ON THE NAM BUFFER SOUNDINGS...DO HAVE SOME CONCERN THAT SOME OF THE STORMS TODAY COULD PRODUCE STRONG...BUT SUB SEVERE...WIND GUSTS TODAY. THERE IS SUFFICIENT INSTABILITY AND SOME DRY AIR ALOFT THAT WOULD MAKE THIS FAVORABLE. STILL HAVE CONCERN FOR SOME STRONG STORMS FOR TUESDAY AFTERNOON AND EVENING AS WELL. WOULD NOT BE TOO SURPRISED TO SEE EASTERN KENTUCKY IN AN SPC SLIGHT RISK BOX FOR TOMORROW. THE REST OF THE FORECAST IS ON TRACK. UPDATE ISSUED AT 647 AM EDT MON SEP 1 2014 CLOUD COVER HAS EXPANDED A BIT FROM EARLIER...SO HAVE ADJUSTED THE SKY COVER TO REFLECT CLOUDIER SKIES THROUGH DAYBREAK. ALSO ADJUSTED TEMPERATURES UP A FEW DEGREES ACROSS THE BOARD AS THE CLOUDS ARE HOLDING TEMPERATURES UP MAINLY IN THE LOW 70S. HRRR CONTINUES TO PAINT OUT SOME ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON...AND THE 06Z NAM HAS ALSO NOW SUPPORTING A FEW SHOWERS AND STORMS. THUS IT DOES LOOK LIKE SOME ACTIVITY CAN BE EXPECTED BY THE AFTERNOON HOURS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 331 AM EDT MON SEP 1 2014 ZONAL FLOW RESIDES ACROSS KENTUCKY THIS MORNING...WITH A SHORTWAVE TROUGH PUSHING ACROSS THE NORTHERN PLAINS. THE ZONAL FLOW FOR TODAY WILL MEAN A QUIETER DAY. HOWEVER...A SUBTLE UPPER LEVEL WAVE WILL PUSH ACROSS CENTRAL/NORTHEAST KENTUCKY THIS AFTERNOON AND EVENING. WHILE OPERATIONAL GUIDANCE SUGGESTS VERY LITTLE IF ANY PRECIPITATION TODAY...HI RES MODELS HAVE BEEN CONSISTENT ON SHOWING ISOLATED TO SCATTERED CONVECTION DEVELOPING TODAY. THE MODEL GUIDANCE DOESN`T SEEM TO MATCH UP TO WHAT THE HI RES MODELS ARE SHOWING. GIVEN THE RECENT HISTORY OF HI RES MODELS DOING FAIRLY WELL WITH CONVECTION...HAVE OPTED TO GO WITH ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON WITH THE HIGHEST CORRIDOR OF POPS FROM SOUTH CENTRAL KENTUCKY...INTO NORTHERN AND NORTHEAST KENTUCKY. HOWEVER...CANNOT RULE OUT A FEW ISOLATED SHOWERS OR STORMS DEVELOPING ON THE HIGHER TERRAIN TO THE SOUTHEAST. WITH MODEST PRECIPITABLE WATER VALUES AROUND 1.7 AND VERY HIGH FREEZING LEVELS (>15KFT) POTENTIAL MAY EXISTS FOR SOME PERIODS OF VERY HEAVY RAIN. FORTUNATELY...STORM MOVEMENT SHOULD BE SUFFICIENT TO LIMIT ANY FLOODING CONCERNS TODAY. THE SHOWERS/STORMS TODAY WILL BE TIED TO THE PEAK INSTABILITY HOURS FROM MID AFTERNOON TO EARLY EVENING...BEFORE DYING OFF. THIS WILL YIELD A QUITE NIGHT ACROSS THE AREA TODAY. CLEARING SKIES COULD YIELD SOME PATCHY FOG...BUT WE MAY KEEP ENOUGH WIND AGAIN TO LIMIT IT TO SOME DEGREE. THE SHORTWAVE TROUGH OVER THE NORTHERN PLAINS WILL SEND A WEAK COLD FRONT INTO THE OHIO RIVER VALLEY REGION. THIS WILL SPARK SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP ON TUESDAY. THESE WILL TRACK SOUTHEAST ACROSS EASTERN KENTUCKY THROUGH THE AFTERNOON AND EVENING HOURS. WITH MODEST 30-40KT BULK SHEAR VALUES...THE POTENTIAL WILL EXISTS FOR SOME LINEAR STORM SEGMENTS CAPABLE OF DAMAGING WINDS. PLAN TO CONTINUE TO HIGHLIGHT THIS POTENTIAL IN THE HWO. THE FRONT WILL WASH OUT AND STALL OVER SOUTHERN KENTUCKY BY THE EVENING HOURS WITH ACTIVITY DYING OUT WITH THE LOSS OF DAYTIME HEATING. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 410 AM EDT MON SEP 1 2014 WARM WEATHER IS EXPECTED TO CONTINUE INTO THE EXTENDED PERIOD. THE EXTENDED PERIOD OF THE FORECAST WILL BEGIN WITH THE TROUGH IN THE NEAR TERM DEPARTING TO THE NORTH AND EAST...WITH A RATHER ZONAL PATTERN TO START OVERALL. THE NEAR TERM COLD FRONT IS EXPECTED TO BE DROPPING OR HAVE DROPPED ACROSS THE REGION AT THE START OF THE PERIOD...FROM TUE NIGHT INTO EARLY ON WEDNESDAY AND BRING ISOLATED TO SCATTERED CONVECTION. THE BOUNDARY SHOULD BECOME MORE ILL DEFINED AND RATHER WASHED OUT ON WEDNESDAY AS IT REACHES THE TN VALLEY REGION. WITH THE BOUNDARY IN THE AREA...CONVECTION WILL REMAIN POSSIBLE MAINLY ACROSS THE SOUTH AND SOUTHEAST ON WEDNESDAY. MID AND UPPER LEVEL RIDGING IS THEN EXPECTED TO BRIEFLY AMPLIFY ACROSS THE SOUTHEASTERN AND MID ATLANTIC STATES THROUGH FRIDAY. AS THE RIDGE BUILDS AND A SHORTWAVE TROUGH OR TWO IN THE ZONAL FLOW MOVES FROM THE CENTRAL PLAINS TOWARD THE LOWER OH VALLEY REGION AND INTO THE MIDDLE OH VALLEY REGION...WHAT IS LEFT OF THE BOUNDARY AND DEEPER MOISTURE SHOULD ALSO BEGIN TO RETREAT BACK INTO THE REGION BY WED NIGHT INTO THU. THIS SHOULD LEAD TO AN ADDITIONAL PERIOD WHERE CONVECTION IS POSSIBLE. THE MODEL CONSENSUS IS FOR THE RIDGE TO BUILD IN BEHIND THIS SHORTWAVE FOR THU NIGHT AND INTO EARLY ON FRI. OVERALL...CONVECTION FROM THU NIGHT INTO FRIDAY MAY HAVE SOMEWHAT OF A DIURNAL FLAVOR. ALSO DURING THIS TIME...A SERIES OF TROUGHS WILL TRAVERSE THE NORTHERN STREAM AND SEND A COLD FRONT SOUTH INTO AND GRADUALLY ACROSS THE THE LOWER OH VALLEY REGION AND EASTERN KENTUCKY THIS WEEKEND. THIS WILL BRING PERIOD OF UNSETTLED WEATHER...WITH PROLONGED CHANCES FOR SHOWERS AND THUNDERSTORMS FROM SATURDAY INTO SUNDAY. TEMPERATURES ARE EXPECTED TO AVERAGE NEAR TO A FEW DEGREES ABOVE NORMAL FROM WED INTO SATURDAY FOR DAYTIME HIGHS...WITH OVERNIGHT LOW HAVING THE GREATER DEPARTURE OF NEARLY 5 DEGREES ON AVERAGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 155 PM EDT MON SEP 1 2014 A LINE OF SCATTERED SHOWERS AND THUNDERSTORMS ARE MOVING IN FROM THE WEST. THIS LINE IS OUT AHEAD OF THE COLD FRONT IN THE WARM AIR. THERE IS A BIT OF CURVATURE TO THE LINE OF HEAVIEST STORMS;...SO WILL BE WATCHING FOR SOME POTENTIALLY STRONG WIND GUSTS AS THE LINE GOES THROUGH. THE MERCER AND LINCOLN COUNTY MESONET SITES SAW WIND GUSTS OF 30 MPH AS THE LINE WENT THROUGH. CURRENT THINKING IS THE MAX GUSTS WILL STAY BELOW 40 MPH AND WILL BE IN THE 20 TO 30 MPH RANGE AS THE STORMS MOVE INTO EASTERN KENTUCKY. THE HEATING WILL BE A LITTLE BETTER...HOWEVER THE STORMS SEEM TO BE WEAKENING A LITTLE BIT. SOME TEMPO IFR IS POSSIBLE WITH THE HEAVIEST STORMS. OTHERWISE VFR CONDITIONS WILL PREVAIL UNTIL 6 TO 8Z WHEN SOME MVFR MIST MAY BE EFFECTING THE TAF SITES. LOOKING FOR VSBY DOWN TO ABOUT 2 SM AT THE TAF SITES BUT DOWN TO 1/2SM IN THE RIVER VALLEYS...ESPECIALLY IN AREAS THAT GET RAIN TODAY. ONCE THE MIST CLEARS IN THE MORNING...EXPECTING TO SEE SOME CONVECTION DEVELOP AGAIN TOMORROW. THE CHANCE FOR STRONG THUNDERSTORMS IS GREATER FOR TOMORROW THAN IT WAS TODAY. THE TIMING OF STORMS FOR TOMORROW IS TOO UNCERTAIN...HOWEVER SHOULD BE AFTER 16Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJ SHORT TERM...KAS LONG TERM...JP AVIATION...JJ
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1221 PM CDT Mon Sep 1 2014 .UPDATE... Issued at 1221 PM CDT MON SEP 1 2014 Updated the AVIATION section. UPDATE Issued at 849 AM CDT MON SEP 1 2014 Clearly evident yesterday`s and even some of last night`s models were unable to resolve and capture several ongoing elements. PoPs have been modified to capture ongoing convection over the east that wasn`t model depicted prior. Also, winds were up quicker than forecast this morning. 12z upper air data shows 30-40kt low level jet already established. Thus, that leads us to the fact we are already at Lake Wind Advisory criteria. Given it`s the holiday, will go ahead with one. Gusty southwest winds expected 10 to 20 mph with 25+ mph winds possible at times. Not necessarily the optimum trajectory, but quite breezy none the less. Meanwhile, kept chance of convection going more aggressively than previously forecast, given the amount of heating we will see ahead of the decaying activity to our west. The HRRR shows some development in this region of less cloud cover over the next several hours, before dying off later in the afternoon. Will see if this actually comes to fruition. For now, will keep PoPs in the chance category. && .SHORT TERM...(Today through Wednesday) Issued at 200 AM CDT MON SEP 1 2014 MCS dropping down across MO will spread its clouds into/across PAH FA this morning. It will also lay out some boundaries, the primary one of which lays out across our northern tier this afternoon, where we`ll have a slgt/small chance mentionable Pop. As the mean energy in the long wave moves across the MS and Wabash river valleys tonight and Tuesday, it will drag this primary boundary into the heart of the FA and result in an uptick in Pops to likely cat or better, particularly during the day Tuesday. This has been a consistent model signal and looks a good bet with fropa thru much of the area by 00Z Wed. The front/boundary hangs up across our southern tier or just to the south Tue night, and returns as a warm sector boundary late Tue night and Wed. This is indicated by several model members so we adjusted Pops accordingly. Temps look to remain summerlike at or just above climo norms from the mid/upr 80s to near 90 for highs, and generally in the u60s/lower 70s for lows, with continued muggy dew points. .LONG TERM...(Wednesday Night through Sunday) Issued at 302 AM CDT MON SEP 1 2014 The PAH forecast area will be under the stabilizing influence (aloft) of a broad mid level ridge late in the week, though some models indicate that, with the substantial diurnal lower trop instability present each day, some deep moist convection may be strong enough to get past the warm mid level cap in some locations during the daytime. Meanwhile, a nrn stream longwave trof will be in the process of lowering mid level heights across most of the CONUS. A sfc cold front is forecast to sink sewd into the OH river valley by sometime early Sat, with some timing differences among the med range models. This feature will provide additional focus for lifting of abundant moist air, thus PoPs are now 40-50 percent during the day Sat behind the front. By Sunday, a drier air mass should be making its way into our region, cutting off pcpn. However, the GFS and its ensemble means suggested the center of the high (over the upper Midwest) may be farther east than the ECMWF and its ensemble means indicated, and therefore some warm advection showers/tstms may erupt just to our west. We will have to wait and see how long the drying effects of the dome of high sfc pressure actually last. Warm and humid conditions will prevail late in the week ahead of the front, with heat indices peaking around 100 Thu and Fri, but especially Fri. For this forecast package, the frontal passage should provide us end-of-the-weekend dewpoints in the 60s along with && .AVIATION... Issued at 1221 PM CDT MON SEP 1 2014 Prob of convection not high enough to include at the Terminals this afternoon. Gusty SW winds will persist, 10-20kt +. Ocnl clouds aoa 12k/ft will continue, with sct-bkn025-035 expected, gradually higher bases with time. Kept best chance of convection tonight, within Prob30`s mainly aft 06z as convective chances increase markedly after midnight. Winds will back to the south and fall to aob 10 kts tonight. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...LAKE WIND ADVISORY until 6 PM CDT this evening FOR ILZ075>078- 080>094. MO...LAKE WIND ADVISORY until 6 PM CDT this evening FOR MOZ076-086- 087-100-107>112-114. IN...LAKE WIND ADVISORY until 6 PM CDT this evening FOR INZ081-082- 085>088. KY...LAKE WIND ADVISORY until 6 PM CDT this evening FOR KYZ001>022. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
121 PM EDT Mon Sep 1 2014 ...Updated Aviation Discussion... ...Forecast Update... Issued at 1153 AM EDT Mon Sep 1 2014 A small cluster of showers with some embedded thunder is progressing quickly across central Kentucky and will be capable of producing some locally gusty winds into the 40-50 mph range as it moves into the Green River Lake region and an area of maximized DCAPE and surface instability. Have updated the forecast grids to reflect this area of precipitation, along with the few other showers that are scattered around the area. Issued at 859 AM EDT Mon Sep 1 2014 Widely scattered showers have formed in a corridor of higher surface dew points and CAPE, and diminished CIN, from Memphis to Detroit. have upped PoPs for a few hours this morning in the northwest LMK CWA to account for this. .SHORT TERM (Now through Tuesday)... Issued at 310 AM EDT Mon Sep 1 2014 A slow-moving cool front to our northwest will bring a noticeable increase in southwesterly winds today, with gusts of 15 to 25 mph likely this afternoon. First off though we may see some isolated low-topped showers this morning, with convergence along a weak low-level jet early this morning already initiating some in central IN. HRRR indicates better coverage than what I`ll have in my forecast, as current guidance coverage already is too high. Cloud cover from the moist low levels and as additional moisture streams into the region today in a deep southwesterly flow should keep high temperatures from getting too far above normal, with readings likely topping out in the mid to upper 80s. The focus for storms this evening will be to our west and northwest, closer to the approaching front. These storms may be able to get into our southern Indiana counties around or after midnight. There still are some uncertainties about how convective development will occur from early to late Tuesday, as a lot will depend on the evolution of these storms moving into our region. Should those storms get in here more toward daybreak, then convective debris could be enough to prevent furthern development during the day Tuesday, despite relatively high precipitable waters. Should those storms die off overnight and leave boundaries behind, Tuesday could become more active with heating. Will leave in likely pops for the day Tuesday, as would lean more towards the latter solution that we`ll see a few breaks in the clouds to generate more storms. .LONG TERM (Tuesday Night through Sunday)... Issued at 305 AM EDT Mon Sep 01 2014 Tuesday Night and Wednesday... Surface high pressure will slide over the Ohio Valley behind the nearly washed out front to our south on Tuesday night. An isolated shower or storm could linger into the evening hours across the south or east CWA, otherwise expect a dry and slightly cooler night. Lows should drop into the upper 60s and around 70. Isolated or widely scattered diurnally driven showers/storms are expected to be possible across southern KY on Wednesday. Most areas will stay dry with mostly sunny skies and highs in the 85 to 88 degree range. Wednesday Night - Friday... The southern CONUS upper ridge will build over the area to end the week, however this will not be enough to suppress diurnally driven convection each afternoon and early evening. Will continue mention of isolated to widely scattered coverage on Thursday, with better coverage on Friday more solidly in the scattered range. Along with this ridge, the heat and humidity will return with highs in the upper 80s to around 90 each day. With dew points in the low 70s each day, conditions will feel quite muggy. The environment should become pretty unstable each afternoon/evening, however the lack of deep layer flow will keep any convection pulse in nature. Lows by Thursday night will be back in the low 70s. Friday Night - Saturday Night... The upper ridge will be suppressed southward to start the weekend, as a wave skirts along the eastern US/Canada border. This will drag a stronger cold front toward our moist and unstable airmass, keeping scattered storms in play on Friday night. Saturday should bring the best chance of storms for the whole forecast period as the front tries to slide through. Have gone with 40-50% coverage. With slightly better deep layer flow over the area, the threat for a few stronger storms seems reasonable. Biggest concern would be gusty winds, along with cloud to ground lightning and brief heavy rainfall. A few storms could linger in our south and east Saturday evening. Expect more mild lows on Friday night with the mercury only dropping to the low 70s. Highs on Saturday will be dependent on convection and where the frontal boundary resides, but it looks like temps will max out around 80 north, to the mid or upper 80s south. Lows Saturday night will be cooler on the north side of the boundary. Look for readings in the 60s. Sunday... Surface high pressure takes back over on Sunday, bringing dry and cooler conditions to start the new work week. Look for highs in the upper 70s and low 80s, with lows Sunday night expected to be in the upper 50s and low 60s! && .AVIATION (18Z TAF Update)... Issued at 121 PM EDT Mon Sep 1 2014 Scattered showers and isolated thunderstorms will be possible this afternoon in the warm, humid, unstable air over central Kentucky. Any convection will be moving quickly and would affect any one airfield only very briefly. For now will stick with VCSH, and monitor radar closely for any helpful AMDs. Winds this afternoon will be gusty from the southwest, gusting into the 22 to 26 knot range. Tonight winds will settle down though there will still be a southerly breeze around 5 to 9 knots as we sit in accelerated flow ahead of an approaching cold front. Isolated convection will be possible, but at this time chances appear slight enough to omit from the TAFs. Toward morning that cold front will be entering the region, bringing a band of showers and thunderstorms along with it. Right now will time it into SDF around dawn and a little later at LEX/BWG, though they could end up coming in a little quicker than that. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........13 Short Term.....RJS Long Term......BJS Aviation.......13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1153 AM EDT Mon Sep 1 2014 ...Forecast Update... Issued at 1153 AM EDT Mon Sep 1 2014 A small cluster of showers with some embedded thunder is progressing quickly across central Kentucky and will be capable of producing some locally gusty winds into the 40-50 mph range as it moves into the Green River Lake region and an area of maximized DCAPE and surface instability. Have updated the forecast grids to reflect this area of precipitation, along with the few other showers that are scattered around the area. Issued at 859 AM EDT Mon Sep 1 2014 Widely scattered showers have formed in a corridor of higher surface dew points and CAPE, and diminished CIN, from Memphis to Detroit. have upped PoPs for a few hours this morning in the northwest LMK CWA to account for this. .SHORT TERM (Now through Tuesday)... Issued at 310 AM EDT Mon Sep 1 2014 A slow-moving cool front to our northwest will bring a noticeable increase in southwesterly winds today, with gusts of 15 to 25 mph likely this afternoon. First off though we may see some isolated low-topped showers this morning, with convergence along a weak low-level jet early this morning already initiating some in central IN. HRRR indicates better coverage than what I`ll have in my forecast, as current guidance coverage already is too high. Cloud cover from the moist low levels and as additional moisture streams into the region today in a deep southwesterly flow should keep high temperatures from getting too far above normal, with readings likely topping out in the mid to upper 80s. The focus for storms this evening will be to our west and northwest, closer to the approaching front. These storms may be able to get into our southern Indiana counties around or after midnight. There still are some uncertainties about how convective development will occur from early to late Tuesday, as a lot will depend on the evolution of these storms moving into our region. Should those storms get in here more toward daybreak, then convective debris could be enough to prevent furthern development during the day Tuesday, despite relatively high precipitable waters. Should those storms die off overnight and leave boundaries behind, Tuesday could become more active with heating. Will leave in likely pops for the day Tuesday, as would lean more towards the latter solution that we`ll see a few breaks in the clouds to generate more storms. .LONG TERM (Tuesday Night through Sunday)... Issued at 305 AM EDT Mon Sep 01 2014 Tuesday Night and Wednesday... Surface high pressure will slide over the Ohio Valley behind the nearly washed out front to our south on Tuesday night. An isolated shower or storm could linger into the evening hours across the south or east CWA, otherwise expect a dry and slightly cooler night. Lows should drop into the upper 60s and around 70. Isolated or widely scattered diurnally driven showers/storms are expected to be possible across southern KY on Wednesday. Most areas will stay dry with mostly sunny skies and highs in the 85 to 88 degree range. Wednesday Night - Friday... The southern CONUS upper ridge will build over the area to end the week, however this will not be enough to suppress diurnally driven convection each afternoon and early evening. Will continue mention of isolated to widely scattered coverage on Thursday, with better coverage on Friday more solidly in the scattered range. Along with this ridge, the heat and humidity will return with highs in the upper 80s to around 90 each day. With dew points in the low 70s each day, conditions will feel quite muggy. The environment should become pretty unstable each afternoon/evening, however the lack of deep layer flow will keep any convection pulse in nature. Lows by Thursday night will be back in the low 70s. Friday Night - Saturday Night... The upper ridge will be suppressed southward to start the weekend, as a wave skirts along the eastern US/Canada border. This will drag a stronger cold front toward our moist and unstable airmass, keeping scattered storms in play on Friday night. Saturday should bring the best chance of storms for the whole forecast period as the front tries to slide through. Have gone with 40-50% coverage. With slightly better deep layer flow over the area, the threat for a few stronger storms seems reasonable. Biggest concern would be gusty winds, along with cloud to ground lightning and brief heavy rainfall. A few storms could linger in our south and east Saturday evening. Expect more mild lows on Friday night with the mercury only dropping to the low 70s. Highs on Saturday will be dependent on convection and where the frontal boundary resides, but it looks like temps will max out around 80 north, to the mid or upper 80s south. Lows Saturday night will be cooler on the north side of the boundary. Look for readings in the 60s. Sunday... Surface high pressure takes back over on Sunday, bringing dry and cooler conditions to start the new work week. Look for highs in the upper 70s and low 80s, with lows Sunday night expected to be in the upper 50s and low 60s! && .AVIATION (12Z TAF Update)... Issued at 640 AM EDT Mon Sep 1 2014 Have a few light rain showers forming north of a KSDF/KLEX line this hour, but even should the rain make the terminals it should be light enough not to reduce visibility much. The bigger factor now is ceilings, with them hovering between MVFR and IFR at those two sites, and KBWG may see it soon too. These clouds will lift by mid morning. An isolated storm still cannot be ruled out later this afternoon, but again coverage too limited to put in TAFs at this time. Should see more storms coming in early Tuesday, first at KSDF as a cool front approaches the region. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........13 Short Term.....RJS Long Term......BJS Aviation.......RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1048 AM EDT MON SEP 1 2014 .UPDATE... ISSUED AT 1048 AM EDT MON SEP 1 2014 UPDATED THE FORECAST TO INCLUDE ALL OF EASTERN KENTUCKY IN THE CHANCE OF PRECIPITATION TODAY BASED ON THE HIGH HRRR AND RUC MODEL OUTPUT AS WELL AS THE CURRENT RADAR. BASED ON THE NAM BUFFER SOUNDINGS...DO HAVE SOME CONCERN THAT SOME OF THE STORMS TODAY COULD PRODUCE STRONG...BUT SUB SEVERE...WIND GUSTS TODAY. THERE IS SUFFICIENT INSTABILITY AND SOME DRY AIR ALOFT THAT WOULD MAKE THIS FAVORABLE. STILL HAVE CONCERN FOR SOME STRONG STORMS FOR TUESDAY AFTERNOON AND EVENING AS WELL. WOULD NOT BE TOO SURPRISED TO SEE EASTERN KENTUCKY IN AN SPC SLIGHT RISK BOX FOR TOMORROW. THE REST OF THE FORECAST IS ON TRACK. UPDATE ISSUED AT 647 AM EDT MON SEP 1 2014 CLOUD COVER HAS EXPANDED A BIT FROM EARLIER...SO HAVE ADJUSTED THE SKY COVER TO REFLECT CLOUDIER SKIES THROUGH DAYBREAK. ALSO ADJUSTED TEMPERATURES UP A FEW DEGREES ACROSS THE BOARD AS THE CLOUDS ARE HOLDING TEMPERATURES UP MAINLY IN THE LOW 70S. HRRR CONTINUES TO PAINT OUT SOME ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON...AND THE 06Z NAM HAS ALSO NOW SUPPORTING A FEW SHOWERS AND STORMS. THUS IT DOES LOOK LIKE SOME ACTIVITY CAN BE EXPECTED BY THE AFTERNOON HOURS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 331 AM EDT MON SEP 1 2014 ZONAL FLOW RESIDES ACROSS KENTUCKY THIS MORNING...WITH A SHORTWAVE TROUGH PUSHING ACROSS THE NORTHERN PLAINS. THE ZONAL FLOW FOR TODAY WILL MEAN A QUIETER DAY. HOWEVER...A SUBTLE UPPER LEVEL WAVE WILL PUSH ACROSS CENTRAL/NORTHEAST KENTUCKY THIS AFTERNOON AND EVENING. WHILE OPERATIONAL GUIDANCE SUGGESTS VERY LITTLE IF ANY PRECIPITATION TODAY...HI RES MODELS HAVE BEEN CONSISTENT ON SHOWING ISOLATED TO SCATTERED CONVECTION DEVELOPING TODAY. THE MODEL GUIDANCE DOESN`T SEEM TO MATCH UP TO WHAT THE HI RES MODELS ARE SHOWING. GIVEN THE RECENT HISTORY OF HI RES MODELS DOING FAIRLY WELL WITH CONVECTION...HAVE OPTED TO GO WITH ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON WITH THE HIGHEST CORRIDOR OF POPS FROM SOUTH CENTRAL KENTUCKY...INTO NORTHERN AND NORTHEAST KENTUCKY. HOWEVER...CANNOT RULE OUT A FEW ISOLATED SHOWERS OR STORMS DEVELOPING ON THE HIGHER TERRAIN TO THE SOUTHEAST. WITH MODEST PRECIPITABLE WATER VALUES AROUND 1.7 AND VERY HIGH FREEZING LEVELS (>15KFT) POTENTIAL MAY EXISTS FOR SOME PERIODS OF VERY HEAVY RAIN. FORTUNATELY...STORM MOVEMENT SHOULD BE SUFFICIENT TO LIMIT ANY FLOODING CONCERNS TODAY. THE SHOWERS/STORMS TODAY WILL BE TIED TO THE PEAK INSTABILITY HOURS FROM MID AFTERNOON TO EARLY EVENING...BEFORE DYING OFF. THIS WILL YIELD A QUITE NIGHT ACROSS THE AREA TODAY. CLEARING SKIES COULD YIELD SOME PATCHY FOG...BUT WE MAY KEEP ENOUGH WIND AGAIN TO LIMIT IT TO SOME DEGREE. THE SHORTWAVE TROUGH OVER THE NORTHERN PLAINS WILL SEND A WEAK COLD FRONT INTO THE OHIO RIVER VALLEY REGION. THIS WILL SPARK SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP ON TUESDAY. THESE WILL TRACK SOUTHEAST ACROSS EASTERN KENTUCKY THROUGH THE AFTERNOON AND EVENING HOURS. WITH MODEST 30-40KT BULK SHEAR VALUES...THE POTENTIAL WILL EXISTS FOR SOME LINEAR STORM SEGMENTS CAPABLE OF DAMAGING WINDS. PLAN TO CONTINUE TO HIGHLIGHT THIS POTENTIAL IN THE HWO. THE FRONT WILL WASH OUT AND STALL OVER SOUTHERN KENTUCKY BY THE EVENING HOURS WITH ACTIVITY DYING OUT WITH THE LOSS OF DAYTIME HEATING. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 410 AM EDT MON SEP 1 2014 WARM WEATHER IS EXPECTED TO CONTINUE INTO THE EXTENDED PERIOD. THE EXTENDED PERIOD OF THE FORECAST WILL BEGIN WITH THE TROUGH IN THE NEAR TERM DEPARTING TO THE NORTH AND EAST...WITH A RATHER ZONAL PATTERN TO START OVERALL. THE NEAR TERM COLD FRONT IS EXPECTED TO BE DROPPING OR HAVE DROPPED ACROSS THE REGION AT THE START OF THE PERIOD...FROM TUE NIGHT INTO EARLY ON WEDNESDAY AND BRING ISOLATED TO SCATTERED CONVECTION. THE BOUNDARY SHOULD BECOME MORE ILL DEFINED AND RATHER WASHED OUT ON WEDNESDAY AS IT REACHES THE TN VALLEY REGION. WITH THE BOUNDARY IN THE AREA...CONVECTION WILL REMAIN POSSIBLE MAINLY ACROSS THE SOUTH AND SOUTHEAST ON WEDNESDAY. MID AND UPPER LEVEL RIDGING IS THEN EXPECTED TO BRIEFLY AMPLIFY ACROSS THE SOUTHEASTERN AND MID ATLANTIC STATES THROUGH FRIDAY. AS THE RIDGE BUILDS AND A SHORTWAVE TROUGH OR TWO IN THE ZONAL FLOW MOVES FROM THE CENTRAL PLAINS TOWARD THE LOWER OH VALLEY REGION AND INTO THE MIDDLE OH VALLEY REGION...WHAT IS LEFT OF THE BOUNDARY AND DEEPER MOISTURE SHOULD ALSO BEGIN TO RETREAT BACK INTO THE REGION BY WED NIGHT INTO THU. THIS SHOULD LEAD TO AN ADDITIONAL PERIOD WHERE CONVECTION IS POSSIBLE. THE MODEL CONSENSUS IS FOR THE RIDGE TO BUILD IN BEHIND THIS SHORTWAVE FOR THU NIGHT AND INTO EARLY ON FRI. OVERALL...CONVECTION FROM THU NIGHT INTO FRIDAY MAY HAVE SOMEWHAT OF A DIURNAL FLAVOR. ALSO DURING THIS TIME...A SERIES OF TROUGHS WILL TRAVERSE THE NORTHERN STREAM AND SEND A COLD FRONT SOUTH INTO AND GRADUALLY ACROSS THE THE LOWER OH VALLEY REGION AND EASTERN KENTUCKY THIS WEEKEND. THIS WILL BRING PERIOD OF UNSETTLED WEATHER...WITH PROLONGED CHANCES FOR SHOWERS AND THUNDERSTORMS FROM SATURDAY INTO SUNDAY. TEMPERATURES ARE EXPECTED TO AVERAGE NEAR TO A FEW DEGREES ABOVE NORMAL FROM WED INTO SATURDAY FOR DAYTIME HIGHS...WITH OVERNIGHT LOW HAVING THE GREATER DEPARTURE OF NEARLY 5 DEGREES ON AVERAGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 647 AM EDT MON SEP 1 2014 LOW CLOUDS HAVE DEVELOPED AND SPREAD ACROSS MUCH OF EASTERN KENTUCKY THIS MORNING. FOR THE MOST PART...MVFR CIGS ARE BEING REPORTED. HOWEVER...A FEW SPOTS IN THE NORTH MAY BE DOWN TO IFR CIGS. WE SHOULD SEE GRADUAL IMPROVEMENT THROUGH THE MORNING HOURS BEFORE VFR CONDITIONS RETURN BY MIDDAY. ISOLATED TO SCATTERED SHOWERS AND STORMS STILL LOOK LIKE A POSSIBILITY THIS AFTERNOON...BUT NO ENOUGH COVERAGE OR CONFIDENCE TO INCLUDE IN THE TAFS. VFR CONDITIONS LOOK TO CONTINUE THROUGH TONIGHT WITH ONLY SOME VERY PATCHY VALLEY FOG. AT THIS TIME...THIS IS NOT EXPECTED TO IMPACT THE TAF SITES TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJ SHORT TERM...KAS LONG TERM...JP AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
849 AM CDT Mon Sep 1 2014 .UPDATE... Issued at 849 AM CDT MON SEP 1 2014 Clearly evident yesterday`s and even some of last night`s models were unable to resolve and capture several ongoing elements. PoPs have been modified to capture ongoing convection over the east that wasn`t model depicted prior. Also, winds were up quicker than forecast this morning. 12z upper air data shows 30-40kt low level jet already established. Thus, that leads us to the fact we are already at Lake Wind Advisory criteria. Given it`s the holiday, will go ahead with one. Gusty southwest winds expected 10 to 20 mph with 25+ mph winds possible at times. Not necessarily the optimum trajectory, but quite breezy none the less. Meanwhile, kept chance of convection going more aggressively than previously forecast, given the amount of heating we will see ahead of the decaying activity to our west. The HRRR shows some development in this region of less cloud cover over the next several hours, before dying off later in the afternoon. Will see if this actually comes to fruition. For now, will keep PoPs in the chance category. && .SHORT TERM...(Today through Wednesday) Issued at 200 AM CDT MON SEP 1 2014 MCS dropping down across MO will spread its clouds into/across PAH FA this morning. It will also lay out some boundaries, the primary one of which lays out across our northern tier this afternoon, where we`ll have a slgt/small chance mentionable Pop. As the mean energy in the long wave moves across the MS and Wabash river valleys tonight and Tuesday, it will drag this primary boundary into the heart of the FA and result in an uptick in Pops to likely cat or better, particularly during the day Tuesday. This has been a consistent model signal and looks a good bet with fropa thru much of the area by 00Z Wed. The front/boundary hangs up across our southern tier or just to the south Tue night, and returns as a warm sector boundary late Tue night and Wed. This is indicated by several model members so we adjusted Pops accordingly. Temps look to remain summerlike at or just above climo norms from the mid/upr 80s to near 90 for highs, and generally in the u60s/lower 70s for lows, with continued muggy dew points. .LONG TERM...(Wednesday Night through Sunday) Issued at 302 AM CDT MON SEP 1 2014 The PAH forecast area will be under the stabilizing influence (aloft) of a broad mid level ridge late in the week, though some models indicate that, with the substantial diurnal lower trop instability present each day, some deep moist convection may be strong enough to get past the warm mid level cap in some locations during the daytime. Meanwhile, a nrn stream longwave trof will be in the process of lowering mid level heights across most of the CONUS. A sfc cold front is forecast to sink sewd into the OH river valley by sometime early Sat, with some timing differences among the med range models. This feature will provide additional focus for lifting of abundant moist air, thus PoPs are now 40-50 percent during the day Sat behind the front. By Sunday, a drier air mass should be making its way into our region, cutting off pcpn. However, the GFS and its ensemble means suggested the center of the high (over the upper Midwest) may be farther east than the ECMWF and its ensemble means indicated, and therefore some warm advection showers/tstms may erupt just to our west. We will have to wait and see how long the drying effects of the dome of high sfc pressure actually last. Warm and humid conditions will prevail late in the week ahead of the front, with heat indices peaking around 100 Thu and Fri, but especially Fri. For this forecast package, the frontal passage should provide us end-of-the-weekend dewpoints in the 60s along with && .AVIATION... Issued at 200 AM CDT MON SEP 1 2014 Will monitor tonight for any possible developing restrictions to vsbys pre dawn. Cigs develop as MCS moves this way, restrictions to MVFR possible at times, but believe will generally stay VFR. Anticipate increasing gradient/winds during the day ahead of approaching boundary. Pops enter forecast tonight but refrain from terminal mention at this writing. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...LAKE WIND ADVISORY until 6 PM CDT this evening FOR ILZ075>078- 080>094. MO...LAKE WIND ADVISORY until 6 PM CDT this evening FOR MOZ076-086- 087-100-107>112-114. IN...LAKE WIND ADVISORY until 6 PM CDT this evening FOR INZ081-082- 085>088. KY...LAKE WIND ADVISORY until 6 PM CDT this evening FOR KYZ001>022. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
859 AM EDT Mon Sep 1 2014 ...Forecast Update... Issued at 859 AM EDT Mon Sep 1 2014 Widely scattered showers have formed in a corridor of higher surface dew points and CAPE, and diminished CIN, from Memphis to Detroit. have upped PoPs for a few hours this morning in the northwest LMK CWA to account for this. .SHORT TERM (Now through Tuesday)... Issued at 310 AM EDT Mon Sep 1 2014 A slow-moving cool front to our northwest will bring a noticeable increase in southwesterly winds today, with gusts of 15 to 25 mph likely this afternoon. First off though we may see some isolated low-topped showers this morning, with convergence along a weak low-level jet early this morning already initiating some in central IN. HRRR indicates better coverage than what I`ll have in my forecast, as current guidance coverage already is too high. Cloud cover from the moist low levels and as additional moisture streams into the region today in a deep southwesterly flow should keep high temperatures from getting too far above normal, with readings likely topping out in the mid to upper 80s. The focus for storms this evening will be to our west and northwest, closer to the approaching front. These storms may be able to get into our southern Indiana counties around or after midnight. There still are some uncertainties about how convective development will occur from early to late Tuesday, as a lot will depend on the evolution of these storms moving into our region. Should those storms get in here more toward daybreak, then convective debris could be enough to prevent furthern development during the day Tuesday, despite relatively high precipitable waters. Should those storms die off overnight and leave boundaries behind, Tuesday could become more active with heating. Will leave in likely pops for the day Tuesday, as would lean more towards the latter solution that we`ll see a few breaks in the clouds to generate more storms. .LONG TERM (Tuesday Night through Sunday)... Issued at 305 AM EDT Mon Sep 01 2014 Tuesday Night and Wednesday... Surface high pressure will slide over the Ohio Valley behind the nearly washed out front to our south on Tuesday night. An isolated shower or storm could linger into the evening hours across the south or east CWA, otherwise expect a dry and slightly cooler night. Lows should drop into the upper 60s and around 70. Isolated or widely scattered diurnally driven showers/storms are expected to be possible across southern KY on Wednesday. Most areas will stay dry with mostly sunny skies and highs in the 85 to 88 degree range. Wednesday Night - Friday... The southern CONUS upper ridge will build over the area to end the week, however this will not be enough to suppress diurnally driven convection each afternoon and early evening. Will continue mention of isolated to widely scattered coverage on Thursday, with better coverage on Friday more solidly in the scattered range. Along with this ridge, the heat and humidity will return with highs in the upper 80s to around 90 each day. With dew points in the low 70s each day, conditions will feel quite muggy. The environment should become pretty unstable each afternoon/evening, however the lack of deep layer flow will keep any convection pulse in nature. Lows by Thursday night will be back in the low 70s. Friday Night - Saturday Night... The upper ridge will be suppressed southward to start the weekend, as a wave skirts along the eastern US/Canada border. This will drag a stronger cold front toward our moist and unstable airmass, keeping scattered storms in play on Friday night. Saturday should bring the best chance of storms for the whole forecast period as the front tries to slide through. Have gone with 40-50% coverage. With slightly better deep layer flow over the area, the threat for a few stronger storms seems reasonable. Biggest concern would be gusty winds, along with cloud to ground lightning and brief heavy rainfall. A few storms could linger in our south and east Saturday evening. Expect more mild lows on Friday night with the mercury only dropping to the low 70s. Highs on Saturday will be dependent on convection and where the frontal boundary resides, but it looks like temps will max out around 80 north, to the mid or upper 80s south. Lows Saturday night will be cooler on the north side of the boundary. Look for readings in the 60s. Sunday... Surface high pressure takes back over on Sunday, bringing dry and cooler conditions to start the new work week. Look for highs in the upper 70s and low 80s, with lows Sunday night expected to be in the upper 50s and low 60s! && .AVIATION (12Z TAF Update)... Issued at 640 AM EDT Mon Sep 1 2014 Have a few light rain showers forming north of a KSDF/KLEX line this hour, but even should the rain make the terminals it should be light enough not to reduce visibility much. The bigger factor now is ceilings, with them hovering between MVFR and IFR at those two sites, and KBWG may see it soon too. These clouds will lift by mid morning. An isolated storm still cannot be ruled out later this afternoon, but again coverage too limited to put in TAFs at this time. Should see more storms coming in early Tuesday, first at KSDF as a cool front approaches the region. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........13 Short Term.....RJS Long Term......BJS Aviation.......RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
647 AM EDT MON SEP 1 2014 .UPDATE... ISSUED AT 647 AM EDT MON SEP 1 2014 CLOUD COVER HAS EXPANDED A BIT FROM EARLIER...SO HAVE ADJUSTED THE SKY COVER TO REFLECT CLOUDIER SKIES THROUGH DAYBREAK. ALSO ADJUSTED TEMPERATURES UP A FEW DEGREES ACROSS THE BOARD AS THE CLOUDS ARE HOLDING TEMPERATURES UP MAINLY IN THE LOW 70S. HRRR CONTINUES TO PAINT OUT SOME ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON...AND THE 06Z NAM HAS ALSO NOW SUPPORTING A FEW SHOWERS AND STORMS. THUS IT DOES LOOK LIKE SOME ACTIVITY CAN BE EXPECTED BY THE AFTERNOON HOURS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 331 AM EDT MON SEP 1 2014 ZONAL FLOW RESIDES ACROSS KENTUCKY THIS MORNING...WITH A SHORTWAVE TROUGH PUSHING ACROSS THE NORTHERN PLAINS. THE ZONAL FLOW FOR TODAY WILL MEAN A QUIETER DAY. HOWEVER...A SUBTLE UPPER LEVEL WAVE WILL PUSH ACROSS CENTRAL/NORTHEAST KENTUCKY THIS AFTERNOON AND EVENING. WHILE OPERATIONAL GUIDANCE SUGGESTS VERY LITTLE IF ANY PRECIPITATION TODAY...HI RES MODELS HAVE BEEN CONSISTENT ON SHOWING ISOLATED TO SCATTERED CONVECTION DEVELOPING TODAY. THE MODEL GUIDANCE DOESN`T SEEM TO MATCH UP TO WHAT THE HI RES MODELS ARE SHOWING. GIVEN THE RECENT HISTORY OF HI RES MODELS DOING FAIRLY WELL WITH CONVECTION...HAVE OPTED TO GO WITH ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON WITH THE HIGHEST CORRIDOR OF POPS FROM SOUTH CENTRAL KENTUCKY...INTO NORTHERN AND NORTHEAST KENTUCKY. HOWEVER...CANNOT RULE OUT A FEW ISOLATED SHOWERS OR STORMS DEVELOPING ON THE HIGHER TERRAIN TO THE SOUTHEAST. WITH MODEST PW`S AROUND 1.7 AND VERY HIGH FREEZING LEVELS (>15KFT) POTENTIAL MAY EXISTS FOR SOME PERIODS OF VERY HEAVY RAIN. FORTUNATELY...STORM MOVEMENT SHOULD BE SUFFICIENT TO LIMIT ANY FLOODING CONCERNS TODAY. THE SHOWERS/STORMS TODAY WILL BE TIED TO THE PEAK INSTABILITY HOURS FROM MID AFTERNOON TO EARLY EVENING...BEFORE DYING OFF. THIS WILL YIELD A QUITE NIGHT ACROSS THE AREA TODAY. CLEARING SKIES COULD YIELD SOME PATCHY FOG...BUT WE MAY KEEP ENOUGH WIND AGAIN TO LIMIT IT TO SOME DEGREE. THE SHORTWAVE TROUGH OVER THE NORTHERN PLAINS WILL SEND A WEAK COLD FRONT INTO THE OHIO RIVER VALLEY REGION. THIS WILL SPARK SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP ON TUESDAY. THESE WILL TRACK SOUTHEAST ACROSS EASTERN KENTUCKY THROUGH THE AFTERNOON AND EVENING HOURS. WITH MODEST 30-40KT BULK SHEAR VALUES...THE POTENTIAL WILL EXISTS FOR SOME LINEAR STORM SEGMENTS CAPABLE OF DAMAGING WINDS. PLAN TO CONTINUE TO HIGHLIGHT THIS POTENTIAL IN THE HWO. THE FRONT WILL WASH OUT AND STALL OVER SOUTHERN KENTUCKY BY THE EVENING HOURS WITH ACTIVITY DYING OUT WITH THE LOSS OF DAYTIME HEATING. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 410 AM EDT MON SEP 1 2014 WARM WEATHER IS EXPECTED TO CONTINUE INTO THE EXTENDED PERIOD. THE EXTENDED PERIOD OF THE FORECAST WILL BEGIN WITH THE TROUGH IN THE NEAR TERM DEPARTING TO THE NORTH AND EAST...WITH A RATHER ZONAL PATTERN TO START OVERALL. THE NEAR TERM COLD FRONT IS EXPECTED TO BE DROPPING OR HAVE DROPPED ACROSS THE REGION AT THE START OF THE PERIOD...FROM TUE NIGHT INTO EARLY ON WEDNESDAY AND BRING ISOLATED TO SCATTERED CONVECTION. THE BOUNDARY SHOULD BECOME MORE ILL DEFINED AND RATHER WASHED OUT ON WEDNESDAY AS IT REACHES THE TN VALLEY REGION. WITH THE BOUNDARY IN THE AREA...CONVECTION WILL REMAIN POSSIBLE MAINLY ACROSS THE SOUTH AND SOUTHEAST ON WEDNESDAY. MID AND UPPER LEVEL RIDGING IS THEN EXPECTED TO BRIEFLY AMPLIFY ACROSS THE SOUTHEASTERN AND MID ATLANTIC STATES THROUGH FRIDAY. AS THE RIDGE BUILDS AND A SHORTWAVE TROUGH OR TWO IN THE ZONAL FLOW MOVES FROM THE CENTRAL PLAINS TOWARD THE LOWER OH VALLEY REGION AND INTO THE MIDDLE OH VALLEY REGION...WHAT IS LEFT OF THE BOUNDARY AND DEEPER MOISTURE SHOULD ALSO BEGIN TO RETREAT BACK INTO THE REGION BY WED NIGHT INTO THU. THIS SHOULD LEAD TO AN ADDITIONAL PERIOD WHERE CONVECTION IS POSSIBLE. THE MODEL CONSENSUS IS FOR THE RIDGE TO BUILD IN BEHIND THIS SHORTWAVE FOR THU NIGHT AND INTO EARLY ON FRI. OVERALL...CONVECTION FROM THU NIGHT INTO FRIDAY MAY HAVE SOMEWHAT OF A DIURNAL FLAVOR. ALSO DURING THIS TIME...A SERIES OF TROUGHS WILL TRAVERSE THE NORTHERN STREAM AND SEND A COLD FRONT SOUTH INTO AND GRADUALLY ACROSS THE THE LOWER OH VALLEY REGION AND EASTERN KENTUCKY THIS WEEKEND. THIS WILL BRING PERIOD OF UNSETTLED WEATHER...WITH PROLONGED CHANCES FOR SHOWERS AND THUNDERSTORMS FROM SATURDAY INTO SUNDAY. TEMPERATURES ARE EXPECTED TO AVERAGE NEAR TO A FEW DEGREES ABOVE NORMAL FROM WED INTO SATURDAY FOR DAYTIME HIGHS...WITH OVERNIGHT LOW HAVING THE GREATER DEPARTURE OF NEARLY 5 DEGREES ON AVERAGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 647 AM EDT MON SEP 1 2014 LOW CLOUDS HAVE DEVELOPED AND SPREAD ACROSS MUCH OF EASTERN KENTUCKY THIS MORNING. FOR THE MOST PART...MVFR CIGS ARE BEING REPORTED. HOWEVER...A FEW SPOTS IN THE NORTH MAY BE DOWN TO IFR CIGS. WE SHOULD SEE GRADUAL IMPROVEMENT THROUGH THE MORNING HOURS BEFORE VFR CONDITIONS RETURN BY MIDDAY. ISOLATED TO SCATTERED SHOWERS AND STORMS STILL LOOK LIKE A POSSIBILITY THIS AFTERNOON...BUT NO ENOUGH COVERAGE OR CONFIDENCE TO INCLUDE IN THE TAFS. VFR CONDITIONS LOOK TO CONTINUE THROUGH TONIGHT WITH ONLY SOME VERY PATCHY VALLEY FOG. AT THIS TIME...THIS IS NOT EXPECTED TO IMPACT THE TAF SITES TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...KAS LONG TERM...JP AVIATION...KAS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
640 AM EDT Mon Sep 1 2014 ...Updated Aviation Discussion... .SHORT TERM (Now through Tuesday)... Issued at 310 AM EDT Mon Sep 1 2014 A slow-moving cool front to our northwest will bring a noticeable increase in southwesterly winds today, with gusts of 15 to 25 mph likely this afternoon. First off though we may see some isolated low-topped showers this morning, with convergence along a weak low-level jet early this morning already initiating some in central IN. HRRR indicates better coverage than what I`ll have in my forecast, as current guidance coverage already is too high. Cloud cover from the moist low levels and as additional moisture streams into the region today in a deep southwesterly flow should keep high temperatures from getting too far above normal, with readings likely topping out in the mid to upper 80s. The focus for storms this evening will be to our west and northwest, closer to the approaching front. These storms may be able to get into our southern Indiana counties around or after midnight. There still are some uncertainties about how convective development will occur from early to late Tuesday, as a lot will depend on the evolution of these storms moving into our region. Should those storms get in here more toward daybreak, then convective debris could be enough to prevent furthern development during the day Tuesday, despite relatively high precipitable waters. Should those storms die off overnight and leave boundaries behind, Tuesday could become more active with heating. Will leave in likely pops for the day Tuesday, as would lean more towards the latter solution that we`ll see a few breaks in the clouds to generate more storms. .LONG TERM (Tuesday Night through Sunday)... Issued at 305 AM EDT Mon Sep 01 2014 Tuesday Night and Wednesday... Surface high pressure will slide over the Ohio Valley behind the nearly washed out front to our south on Tuesday night. An isolated shower or storm could linger into the evening hours across the south or east CWA, otherwise expect a dry and slightly cooler night. Lows should drop into the upper 60s and around 70. Isolated or widely scattered diurnally driven showers/storms are expected to be possible across southern KY on Wednesday. Most areas will stay dry with mostly sunny skies and highs in the 85 to 88 degree range. Wednesday Night - Friday... The southern CONUS upper ridge will build over the area to end the week, however this will not be enough to suppress diurnally driven convection each afternoon and early evening. Will continue mention of isolated to widely scattered coverage on Thursday, with better coverage on Friday more solidly in the scattered range. Along with this ridge, the heat and humidity will return with highs in the upper 80s to around 90 each day. With dew points in the low 70s each day, conditions will feel quite muggy. The environment should become pretty unstable each afternoon/evening, however the lack of deep layer flow will keep any convection pulse in nature. Lows by Thursday night will be back in the low 70s. Friday Night - Saturday Night... The upper ridge will be suppressed southward to start the weekend, as a wave skirts along the eastern US/Canada border. This will drag a stronger cold front toward our moist and unstable airmass, keeping scattered storms in play on Friday night. Saturday should bring the best chance of storms for the whole forecast period as the front tries to slide through. Have gone with 40-50% coverage. With slightly better deep layer flow over the area, the threat for a few stronger storms seems reasonable. Biggest concern would be gusty winds, along with cloud to ground lightning and brief heavy rainfall. A few storms could linger in our south and east Saturday evening. Expect more mild lows on Friday night with the mercury only dropping to the low 70s. Highs on Saturday will be dependent on convection and where the frontal boundary resides, but it looks like temps will max out around 80 north, to the mid or upper 80s south. Lows Saturday night will be cooler on the north side of the boundary. Look for readings in the 60s. Sunday... Surface high pressure takes back over on Sunday, bringing dry and cooler conditions to start the new work week. Look for highs in the upper 70s and low 80s, with lows Sunday night expected to be in the upper 50s and low 60s! && .AVIATION (12Z TAF Update)... Issued at 640 AM EDT Mon Sep 1 2014 Have a few light rain showers forming north of a KSDF/KLEX line this hour, but even should the rain make the terminals it should be light enough not to reduce visibility much. The bigger factor now is ceilings, with them hovering between MVFR and IFR at those two sites, and KBWG may see it soon too. These clouds will lift by mid morning. An isolated storm still cannot be ruled out later this afternoon, but again coverage too limited to put in TAFs at this time. Should see more storms coming in early Tuesday, first at KSDF as a cool front approaches the region. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Short Term........RJS Long Term.........BJS Aviation..........RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
315 AM EDT Mon Sep 1 2014 .SHORT TERM (Now through Tuesday)... Issued at 310 AM EDT Mon Sep 1 2014 A slow-moving cool front to our northwest will bring a noticeable increase in southwesterly winds today, with gusts of 15 to 25 mph likely this afternoon. First off though we may see some isolated low-topped showers this morning, with convergence along a weak low-level jet early this morning already initiating some in central IN. HRRR indicates better coverage than what I`ll have in my forecast, as current guidance coverage already is too high. Cloud cover from the moist low levels and as additional moisture streams into the region today in a deep southwesterly flow should keep high temperatures from getting too far above normal, with readings likely topping out in the mid to upper 80s. The focus for storms this evening will be to our west and northwest, closer to the approaching front. These storms may be able to get into our southern Indiana counties around or after midnight. There still are some uncertainties about how convective development will occur from early to late Tuesday, as a lot will depend on the evolution of these storms moving into our region. Should those storms get in here more toward daybreak, then convective debris could be enough to prevent furthern development during the day Tuesday, despite relatively high precipitable waters. Should those storms die off overnight and leave boundaries behind, Tuesday could become more active with heating. Will leave in likely pops for the day Tuesday, as would lean more towards the latter solution that we`ll see a few breaks in the clouds to generate more storms. .LONG TERM (Tuesday Night through Sunday)... Issued at 305 AM EDT Mon Sep 01 2014 Tuesday Night and Wednesday... Surface high pressure will slide over the Ohio Valley behind the nearly washed out front to our south on Tuesday night. An isolated shower or storm could linger into the evening hours across the south or east CWA, otherwise expect a dry and slightly cooler night. Lows should drop into the upper 60s and around 70. Isolated or widely scattered diurnally driven showers/storms are expected to be possible across southern KY on Wednesday. Most areas will stay dry with mostly sunny skies and highs in the 85 to 88 degree range. Wednesday Night - Friday... The southern CONUS upper ridge will build over the area to end the week, however this will not be enough to suppress diurnally driven convection each afternoon and early evening. Will continue mention of isolated to widely scattered coverage on Thursday, with better coverage on Friday more solidly in the scattered range. Along with this ridge, the heat and humidity will return with highs in the upper 80s to around 90 each day. With dew points in the low 70s each day, conditions will feel quite muggy. The environment should become pretty unstable each afternoon/evening, however the lack of deep layer flow will keep any convection pulse in nature. Lows by Thursday night will be back in the low 70s. Friday Night - Saturday Night... The upper ridge will be suppressed southward to start the weekend, as a wave skirts along the eastern US/Canada border. This will drag a stronger cold front toward our moist and unstable airmass, keeping scattered storms in play on Friday night. Saturday should bring the best chance of storms for the whole forecast period as the front tries to slide through. Have gone with 40-50% coverage. With slightly better deep layer flow over the area, the threat for a few stronger storms seems reasonable. Biggest concern would be gusty winds, along with cloud to ground lightning and brief heavy rainfall. A few storms could linger in our south and east Saturday evening. Expect more mild lows on Friday night with the mercury only dropping to the low 70s. Highs on Saturday will be dependent on convection and where the frontal boundary resides, but it looks like temps will max out around 80 north, to the mid or upper 80s south. Lows Saturday night will be cooler on the north side of the boundary. Look for readings in the 60s. Sunday... Surface high pressure takes back over on Sunday, bringing dry and cooler conditions to start the new work week. Look for highs in the upper 70s and low 80s, with lows Sunday night expected to be in the upper 50s and low 60s! && .AVIATION (06Z TAF Update)... Issued at 120 AM EDT Mon Sep 1 2014 Have some mid-level drying out their now, helping to rid the region of showers/storms for now, but not necessarily lower-level issues. Each of the terminals may see some periods of MVFR clouds through daybreak. Then we will see winds pick up from the southwest, ahead of a cold front approaching from the northwest. Gusts of 20-25 knots are possible through the day. An isolated pop-up storm is possible in the afternoon, but not confident enough to put in the forecast at this time. The better chance for rain will come Tuesday. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Short Term........RJS Long Term.........BJS Aviation..........RJS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
940 PM EDT TUE SEP 2 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION LATE TONIGHT THROUGH EARLY WEDNESDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION LATER WEDNESDAY THROUGH THURSDAY. THE NEXT COLD FRONT WILL MOVE THROUGH FRIDAY NIGHT. && .NEAR TERM /THROUGH WEDNESDAY/... 930 PM UPDATE: LATEST RADAR INDICATES THAT THE FIRST WAVE OF SHWRS AND TSTMS HAS MOVED E ACROSS NRN PTNS OF THE FA AS OF MID EVE. ONE NARROW BAND OF TSTMS OVR CNTRL AND NRN PTNS OF PISCATAQUIS COUNTY NORTHEAST OF THE N END OF MOOSEHEAD LK MAY BE RESULTING IN LCLZD STREAM FLOODING IN THIS AREA. OTHERWISE RNFL HAS BEEN LGT. BOTH 3-6 HR SYNOPTIC AND HRRR (HRLY) GUIDANCE SUGGESTS MORE GENERAL RNFL MOVG ACROSS ALL OF THE FA LATER TNGT...WITH THE BEST POTENTIAL OF ELEVATED CNVCTN RE-ALIGNING OVR WSW AND DOWNEAST PTNS OF THE FA WHERE MUCAPES WILL REMAIN NEAR 1000 J/KG WELL INTO THE LATE NGT. OTHERWISE...WE INCREASED CVRG OF FOG OVRNGT ACROSS THE SRN HLF OF THE FA BASED ON LATEST OBS ALREADY SHOWING MORE DENSE FOG THERE. OTHERWISE...HRLY FCST TEMPS TO POSTED OVRNGT LOWS AT 5 TO 6 AM WERE MODIFIED SLGTLY BASED ON TRENDS FROM 9 PM OBS FROM THE PREV FCST OF TEMPS AT 9 PM. ORGNL DISC: THE AREA IS CURRENTLY IN A HUMID AIRMASS AHEAD OF A COLD FRONT WITH LINGERING LOW CLOUDS DOWNEAST. THERE HAVE BEEN SOME SHOWERS ACROSS THE NORTH THIS AFTERNOON HOWEVER WE EXPECT MORE WIDESPREAD SHOWERS AND THUNDERSTORMS TO OCCUR TONIGHT WITH THE ACTUAL COLD FRONTAL PASSAGE. SHOWERS/STORMS WILL ARRIVE THIS EVENING IN THE NORTH AND WEST AND REACH DOWNEAST AREAS OVERNIGHT. FORECAST MODELS DO DEPICT CAPES OF 500 TO 1000 K/KG ACROSS THE NORTH AND WEST BUT THIS BECOME MAINLY ELEVATED CAPE AND LAPSE RATES ARE NOT PARTICULARLY IMPRESSIVE. FOR THIS REASON DO NOT SEE A HIGH THREAT FOR SEVERE WEATHER BUT WITH PWATS OF 1.5 TO 2.0 INCHES ALONG WITH A DEEP WARM CLOUD LAYER THERE WILL BE THE POTENTIAL FOR SOME HEAVY RAIN WITH THESE STORMS...ESPECIALLY IN THE NORTH THIS EVENING SO DID ADD THE ENHANCED WORDING OF HEAVY RAIN TO THE N/W ZONES THROUGH THE EVENING. ALSO EXPECT SOME FOG TO DEVELOP ONCE AGAIN OVERNIGHT. THE FRONT WILL CLEAR EASTERN AREAS EARLY WEDNESDAY MORNING WITH ANY LEFT OVER SHOWERS ENDING. THE REMAINDER OF THE DAY WILL FEATURE MAINLY SUNNY SKIES IN THE SOUTH WITH A MIX OF SUN AND CLOUDS NORTH WITH THE CHANCE OF SOME SCATTERED SHOWERS ONCE AGAIN BY AFTERNOON AS A WEAK DISTURBANCE MOVES THROUGH. HIGHS WILL BE IN THE 70S TO AROUND 80 WITH LOWER HUMIDITY. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, HIGH PRESSURE WILL BE POSITIONED JUST SOUTH OF THE GULF OF MAINE. WITH US BEING JUST NORTH OF THE HIGH, LOOK FOR STABLE WESTERLY FLOW WITH DRY CONDITIONS AND GENERALLY MOSTLY CLEAR SKIES. ON FRIDAY, THE HIGH MOVES EAST FURTHER OUT INTO THE NORTH ATLANTIC, AND A COLD FRONT BEGINS TO APPROACH FROM THE WEST. THIS WILL LEAD TO A SOUTHERLY BREEZE AND MUGGIER AIRMASS. CLOUDS WILL INCREASE THROUGH THE DAY FRIDAY, BUT IT APPEARS PRECIP CHANCES WILL HOLD OFF UNTIL FRIDAY EVENING FOR MOST PLACES EXCEPT PERHAPS FAR NORTH/NORTHWEST MAINE. MODELS ARE IN GOOD AGREEMENT THROUGH FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A COLD FRONT WILL MOVE THROUGH FROM NORTHWEST TO SOUTHEAST FRIDAY NIGHT, WITH SHOWERS AND STORMS POSSIBLE. HIGH PRESSURE AND COOLER AIR BUILD IN FROM THE NORTH FOR SATURDAY AND SUNDAY, ALTHOUGH THERE IS SOME QUESTION AS TO HOW QUICKLY THE FRONT CAN CLEAR DOWNEAST MAINE. BUT GENERALLY, IMPROVING WEATHER FROM NORTH TO SOUTH ON THE WEEKEND, WITH VERY LIKELY THAT EVEN DOWNEAST WILL BE DRY FOR SUNDAY. ANOTHER WEAK COLD FRONT IS EXPECTED TO PASS THROUGH AROUND SUNDAY NIGHT OR MONDAY, WITH THE FRONT PROBABLY LACKING ANY PRECIPITATION. THIS WILL KEEP TEMPERATURES NEAR OR A BIT BELOW AVERAGE INTO EARLY NEXT WEEK. IF WE HAVE A NIGHT WHERE HIGH PRESSURE SETS UP JUST RIGHT, THERE COULD BE SOME FROST IN MORE PROTECTED VALLEYS. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... NEAR TERM: EXPECT CONDITIONS TO DETERIORATE ONCE AGAIN TONIGHT AS SHOWERS AND POTENTIAL THUNDERSTORMS MOVE IN WITH A COLD FRONT AND LOW STRATUS AND FOG BECOMES AN ISSUE ALONG THE COAST. EXPECT IFR ONCE AGAIN BY THE OVERNIGHT IN THE NORTH WITH LIFR FOR THE SOUTHERN SITES. CONDITIONS IMPROVE TO VFR THROUGH WEDNESDAY MORNING BEHIND THE FRONT. SHORT TERM: VFR EXPECTED WEDNESDAY NIGHT THROUGH FRIDAY, WITH THE POSSIBLE EXCEPTION OF PATCHY FOG EARLY THURSDAY MORNING. MVFR AND IFR POSSIBLE FRIDAY NIGHT AS A COLD FRONT PASSES THROUGH, THEN IMPROVING TO VFR FOR MOST AREAS BY LATE SATURDAY, WITH VFR CONTINUING INTO EARLY NEXT WEEK. && .MARINE... NEAR TERM: FOG WILL CONTINUE TO BE AN ISSUE THROUGH TONIGHT WITH SOME SHOWERS AND THUNDERSTORMS ALSO MOVING THROUGH TONIGHT WITH A COLD FRONT. HOWEVER WINDS/SEAS REMAIN BELOW SCA LEVELS. CONDITIONS CLEAR WEDNESDAY WITH WEST WINDS BEHIND THE FRONT. SHORT TERM: SUB SMALL CRAFT WINDS AND SEAS WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. AS A COLD FRONT APPROACHES FRIDAY, SOUTH WINDS AND SEAS WILL BEGIN TO INCREASE, WITH BOTH POSSIBLY REACHING SMALL CRAFT LEVELS LATE FRIDAY AFTERNOON AND PERSISTING THROUGH FRIDAY NIGHT, BEFORE CONDITIONS IMPROVE FOR SATURDAY AND SUNDAY BACK TO SUB SMALL CRAFT LEVELS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...VJN SHORT TERM...FOISY LONG TERM...FOISY AVIATION...VJN/FOISY MARINE...VJN/FOISY
AREA FORECAST DISCUSSION
NWS GRAY ME
1240 AM EDT MON SEP 1 2014 .SYNOPSIS... A COLD FRONT WILL DROP SOUTHEAST THROUGH THE REGION O0VERNIGHT AND WILL STALL OFF THE COAST ON MONDAY. A SECOND COLD FRONT WILL APPROACH FROM THE WEST ON TUESDAY AND WILL CROSS THE REGION TUESDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST ON WEDNESDAY AND WILL CREST OVER THE REGION THURSDAY BEFORE SHIFTING OFFSHORE. HIGH PRESSURE WILL HOLD OFF THE NEW ENGLAND COAST ON FRIDAY. A COLD FRONT WILL CROSS THE AREA ON SATURDAY. && .NEAR TERM /THROUGH TODAY/... UPDATE... HAVE UPDATED THE GRIDS BASED ON CURRENT CONDITIONS. SOAKING RAINS IN THE PORTLAND AREA HAVE SHIFTED EAST AND INTO THE GULF OF MAINE EARLY THIS MORNING. IN ITS WAKE...PLENTY OF FOG WILL DEVELOP WITH LOW LEVEL MOISTURE IN PLACE AND CLEARING SKIES. MODIFIED CLOUD AND DEW POINT GRIDS...OTHERWISE...NO SIGNIFICANT CHANGES THIS HOUR. PREV DISC... SHOWERS AND EMBEDDED TSTMS CONTINUE TO SLOWLY MOVE EWD ACROSS THE SRN PART OF THE FORECAST AREA. IN A LINE FROM JUST E OF KCON TO KPWM RAIN IS HEAVY AT TIMES...WITH OCNL RATES IN EXCESS OF 3 INCHES/HR. BACK EDGE IS QUICKLY APPROACHING THE COAST...THOUGH HEAVIEST RATES WILL LINGER WITHIN THIS LINE. TO EITHER SIDE OF THAT LINE...A LIGHTER RAIN WILL CONTINUE TO FALL FOR THE NEXT COUPLE OF HOURS. HAVE ADJUSTED POP BASED ON RADAR TREND AND LATEST HI-RES MODEL GUIDANCE. SHOULD BE A MOSTLY DRY NIGHT ONCE THIS RNFL CLEARS THE COAST...EXCEPT FOR THE FAR NRN ZONES WHERE LINGERING CONVECTION ASSOCIATED WITH LEADING EDGE OF S/WV TROF MAY HOLD TOGETHER. PREVIOUS DISCUSSION...A SHORT WAVE TROUGH APPROACHING FROM THE WEST WILL WEAKEN THIS EVENING AS IT MOVES EASTWARD TOWARD NORTHERN NEW ENGLAND. THE ATTENDANT SFC COLD FRONT WILL APPROACH AS WELL...AND ALSO WEAKEN. A SHIELD OF LIGHT RAIN CONTINUES TO TRAVERSE ACROSS NORTHERN AND CENTRAL ZONES AS OF 19Z THIS SUNDAY AFTERNOON. THIS WILL STABILIZE THE AIRMASS ACROSS THIS AREA. HOWEVER...ALONG THE COASTAL PLAIN SWWD OVER TO SOUTHERNMOST NH SHOULD REMAIN MOSTLY DRY FOR THE NEXT SEVERAL HOURS. THEREFORE...THESE AREAS SHOULD RETAIN THE INSTABILITY /1000-1500 J/KG SBCAPE/ THROUGH EARLY EVENING. THE QUESTION IS DO THUNDERSTORMS DEVELOP IN THIS AREA. SEVERAL OF THE LATEST RUNS OF THE HRRR CONTINUE TO SHOW THUNDERSTORMS WILL HEAVY RAINFALL MOVING ACROSS SOUTHERNMOST NH AND SOUTHERNMOST ME BETWEEN 22Z AND 03Z. THIS SEEMS REASONABLE GIVEN THE CURRENT MESOSCALE SETUP. AS A RESULT WILL CONTINUE WITH HIGH POPS...ESPECIALLY IN THIS AREA. MODERATE DEEP LAYER SHEAR MAY AID IN A FEW OF THESE STORMS BECOMING STRONG...WITH GUSTY WINDS BEING THE MAIN THREAT. WITH PWATS INCREASING TO AROUND 2 INCHES BY EARLY EVENING...TORRENTIAL DOWNPOURS WILL BE LIKELY IN ANY THUNDERSTORM. THERE IS A LOW PROB FOR TRAINING STORMS ACROSS SOUTHERN NH AND SOUTHERNMOST ME...SO LOCALIZED FLASH FLOODING WILL BE POSSIBLE THIS EVENING. THE BULK OF THE ACTIVITY SHOULD MOVE OFFSHORE AROUND MIDNIGHT LEADING TO A MAINLY DRY OVERNIGHT. && .SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/... ON MONDAY...THE SHORT WAVE TROUGH WILL DEPART IN THE MORNING. STILL...WITH MODERATE AMOUNTS OF LOW LEVEL THETA-E IN TANDEM WITH SLIGHTLY COOLER TEMPS ALOFT AND A WEAK SFC FRONT IN THE VCNTY...WE COULD SEE A FEW SHOWERS DURING THE DAY...PERHAPS A THUNDERSTORM. HOWEVER...ACTIVITY SHOULD BE FEW AND FAR BETWEEN...WITH HIGHEST POPS ACROSS CENTRAL AND NORTHERN ZONES. HUMID CONDITIONS WILL CONTINUE. MUGGY AND QUIET MONDAY NIGHT. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... COLD FRONT APPROACHES FROM THE WEST ON TUESDAY AND WILL SET THE STAGE FOR POSSIBLE SEVERE WEATHER. PRE-FRONTAL TROUGH FORECAST TO PUSH IN FROM THE WEST DURING PRIME TIME HEATING. MODERATE CAPES AND INCREASING SHEAR DURING THE AFTERNOON AND EVENING HOURS WILL LIKELY RESULT IN MORE ORGANIZED CONVECTION DURING THE LATE AFTERNOON AND EVENING WITH DAMAGING WINDS THE MAIN THREAT. STRONGER CELLS MAY ALSO PRODUCE SOME HAIL BUT FREEZING LEVELS WILL BE QUITE HIGH SO NOT LOOKING FOR MUCH IN THE WAY OF SEVERE HAIL. WILL SEE A HOT AND MUGGY DAY WITH HIGHS RANGING THROUGH THE 80S. COLD FRONT WILL PUSH OFFSHORE TUESDAY NIGHT WITH CONVECTION ENDING ACROSS THE REGION BY MIDNIGHT. HIGH PRESSURE BUILDING IN FROM THE WEST WILL BRING CLEARING DOWNWIND OF THE MOUNTAINS. LOW TEMPS OVERNIGHT WILL RANGE THROUGH THE 60S. COOLER AND MUCH DRIER AIR PUSHES IN FOR WEDNESDAY AS HIGH PRESSURE CONTINUES TO BUILD INTO THE NORTHEAST. SHOULD SEE A MOSTLY SUNNY DAY WITH HIGHS FROM THE MID 70S TO LOWER 80S. FAIR WEATHER WILL CONTINUE THURSDAY AND FRIDAY AS HIGH PRESSURE CONTINUES TO BUILD SOUTH OF THE REGION FINALLY PUSHING OFFSHORE ON FRIDAY. AFTER A STELLAR LATE SUMMER DAY ON THURSDAY...RETURN FLOW WILL BEGIN TO PUMP WARMER AND MORE HUMID AIR BACK INTO THE REGION ON FRIDAY. MAY SEE ENOUGH INSTABILITY CREEP INTO THE CONNECTICUT VALLEY LATE FRIDAY TO KICK OFF AN ISOLATED SHOWER OR THUNDERSTORM BUT THE MAJORITY OF THE FORECAST AREA WILL SEE A DRY DAY. RATHER STRONG LOOKING COLD FRONT FORECAST TO PUSH IN FROM THE WEST ON SATURDAY WHICH COULD PRODUCE ANOTHER ROUND OF SEVERE THUNDERSTORMS. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... .SHORT TERM...LOCAL IFR IN SHOWERS AND THUNDERSTORMS THIS EVENING. AFTER MIDNIGHT...FOG AND SOME LOW STRATUS MAY DEVELOP AND RESULT IN LOW CONDITIONS AS WELL. MAINLY VFR EXPECTED ON MONDAY OUTSIDE OF WDLY SCT SHOWERS. .LONG TERM...MAINLY VFR EXPECTED OUTSIDE OF ANY SHOWERS AND THUNDERSTORMS TUE EVE/NIGHT. SOME VALLEY FOG AND COASTAL STRATUS POSSIBLE DURING THE PERIOD LATE AT NIGHT. && .MARINE... .SHORT TERM...HAVE DROPPED THE SCAS FOR TONIGHT. .LONG TERM...SUB-SCA EXPECTED TUE THROUGH FRI. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
658 PM EDT MON SEP 1 2014 .AVIATION... //DISCUSSION... CONVECTION WILL BE ENDING AT THE BEGINNING OF THE FORECAST PERIOD EVEN AS SURFACE TROUGH IS LAGGING WELL TO THE WEST. LIGHT SOUTHWEST FLOW IN ADVANCE OF THIS FEATURE WILL MAINTAIN ABUNDANT LOW LEVEL MOISTURE INTO TONIGHT WITH PATCHY/AREAS OF FOG AND STRATUS AGAIN LATE TONIGHT INTO TUESDAY MORNING. DRIER AIR THEN MIXES INTO THE AREA FROM MID/LATE MORNING TUESDAY ON INTO THE AFTERNOON WITH VFR CONDITIONS EXPECTED WITH TIME. FOR DTW...REMAINING SHRAS WITH PERHAPS A RUMBLE OF THUNDER WILL BE MOVING EAST AND SOUTHEAST OF THE TERMINAL AS THIS FORECAST PERIOD BEGINS. OTHERWISE...PATCHY FOG/STRATUS WILL BE POSSIBLE IN THE 07Z TO 14Z TIME FRAME. //DTW THRESHOLD THREATS... * LOW CONFIDENCE THAT A THUNDERSTORM WILL IMPACT THE TERMINAL THRU 01Z THIS EVENING. * LOW CONFIDENCE IN CEILINGS BELOW 5000 FEET LATE TONIGHT INTO EARLY TUESDAY. && .PREV DISCUSSION...ISSUED 244 PM EDT MON SEP 1 2014 SHORT TERM...THIS EVENING AND TONIGHT 18Z SPECIAL CONFIRMS THE WARMER COLUMN DEPICTED BY THE RAP AND THEN SOME. 900MB INVERSION IS QUITE A BIT MORE ROBUST THAN DEPICTED BY THE GUIDANCE AS IS THE 600MB CAP. THUS, EVEN THE MOST TAME DEPICTIONS OF CONVECTION IN THE NWP ARE LIKELY TOO AGGRESSIVE AND CONCERNS REGARDING CAPPING NOTED IN THE MORNING UPDATE ARE CONFIRMED. UPDRAFTS WILL STRUGGLE ACROSS MOST OF THE CWA WITH THE EXCEPTION OF LOCATIONS NORTH OF I-69 AND ESPECIALLY WEST OF US-23 WHERE MID-LEVEL COOLING AND FORCING WILL BE MAXIMIZED. WITH THE LINE ALREADY MARCHING TOWARD THIS AREA, EXPECT THAT THE ABUNDANCE OF MID-LEVEL DRY AIR AND UNIDIRECTIONAL FLOW ABOVE 1.5KM WILL SUPPORT BOWING SEGMENTS CARRYING A LOW-END SEVERE WIND THREAT. IN ADDITION, ISOLATED TORNADO THREAT OUTLINED IN THE EARLIER UPDATE REMAINS IN TACT. FOR REMAINING AREAS, EXPECT NOTHING MORE THAN A GUST TO 40 MPH. IN ADDITION, BACKED OFF ON POPS AS EARLIER SUSPICIONS REGARDING COVERAGE POTENTIAL STILL LOOM. A WEAK COLD FRONT WILL SAG THROUGH THE AREA TONIGHT. FRONTAL INVERSION WILL PROMOTE EXPANSION OF STRATUS LATE TONIGHT, BUT EXPECT THAT MOISTURE WILL BE TOO SHALLOW AND FORCING TOO WEAK TO SUPPORT ANY LEGITIMATE COVERAGE OR INTENSITY OF SHOWERS. WITH UPPER SUPPORT IN THE FORM OF A SHEARING SHORTWAVE NOT SCHEDULED TO ARRIVE UNTIL TUESDAY MORNING PER 12Z GUIDANCE, AND MAINLY SOUTH OF THE AREA AT THAT, NOTHING MORE THAN A CHC POP IS WARRANTED ATTM. LONG TERM...TUESDAY THROUGH NEXT MONDAY A COLD FRONT WILL BE SOUTHEAST OF THE CWA TO START OUT TUESDAY MORNING. HOWEVER A MID LEVEL SHORTWAVE RIDING NORTHEAST ALONG THE FRONT WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS TO THE AREA TUESDAY MORNING. AFTER THE SHORTWAVE TRACKS OFF TO THE NORTHEAST SIGNIFICANT DRYING WILL TAKE PLACE AS A SLUG OF 30 PERCENT RELATIVE HUMIDITY AT 700 MB ADVECTS IN FROM THE WEST...ENDING RAIN CHANCES QUICKLY EARLY TUESDAY AFTERNOON. WHILE THERE IS STILL SOME UNCERTAINTY REGARDING HOW FAR WEST THE RAIN WILL FALL GIVEN THE PUSH OF DRY AIR ADVECTING IN...THE LATEST SUITE OF MODELS HAS THE DRIER AIR PUSHING IN A BIT SOONER THAN THE 00Z RUNS. THEREFORE WILL NUDGE THE FORECAST A BIT DRIER TUESDAY AFTERNOON FROM THE PREVIOUS FORECAST. DESPITE THE PASSAGE OF A COLD FRONT THERE ISN`T A LARGE PUSH OF COLD AIR ASSOCIATED WITH IT...MEANING DAYTIME HIGHS ARE EXPECTED TO GET AROUND 80 TUESDAY AFTERNOON BEHIND THE FRONT. RIDGING WILL KEEP THE FORECAST DRY THROUGH WEDNESDAY AS REBOUNDING HEIGHTS ALLOW DAYTIME HIGHS TO GET BACK INTO THE LOWER 80S BY WEDNESDAY AFTERNOON. MOISTURE SURGE FROM THE GULF OF MEXICO COMMENCES ON THURSDAY AS A LOW CHANCE FOR CONVECTION EXISTS WITHIN THE WARM SECTOR OF A REGION-WIDE LOW PRESSURE SYSTEM. BEST CHANCE FOR THUNDERSTORMS /POSSIBLY SEVERE/ WILL BE FRIDAY AS WARM AND MOIST AIRMASS (85/70 T/TD) IS IN PLACE ALONG WITH FORECASTED CAPE OF 3000 J/KG. BULK SHEAR INCREASES TO NEAR 30 KT IN THE 1-6 KM LAYER AS WELL. THESE INGREDIENTS WILL BE IN PLACE AS A RAGGED COLD FRONT CROSSES THE STATE. THIS BRINGS A TRIPLE THREAT OF SEVERE WEATHER WITH WIND...HAIL...AND ISOLATED TORNADOES ALL POSSIBLE MARINE... SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH THE CENTRAL GREAT LAKES TONIGHT AS A COLD FRONT MOVES THROUGH LAKE HURON AND LOWER MICHIGAN. SOME OF THESE STORMS MAY BE SEVERE...MAINLY ACROSS THE NORTHERN PORTION OF LAKE HURON. HIGH PRESSURE WILL BUILD INTO THE REGION BEHIND THIS FRONT ON TUESDAY...WHICH WILL REMAIN IN CONTROL OF THE WEATHER THROUGH THURSDAY...PROVIDING FAVORABLE BOATING CONDITIONS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....99 SHORT TERM...JVC LONG TERM....KURIMSKI/MM MARINE.......KURIMSKI YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
244 PM EDT MON SEP 1 2014 .SHORT TERM...THIS EVENING AND TONIGHT 18Z SPECIAL CONFIRMS THE WARMER COLUMN DEPICTED BY THE RAP AND THEN SOME. 900MB INVERSION IS QUITE A BIT MORE ROBUST THAN DEPICTED BY THE GUIDANCE AS IS THE 600MB CAP. THUS, EVEN THE MOST TAME DEPICTIONS OF CONVECTION IN THE NWP ARE LIKELY TOO AGGRESSIVE AND CONCERNS REGARDING CAPPING NOTED IN THE MORNING UPDATE ARE CONFIRMED. UPDRAFTS WILL STRUGGLE ACROSS MOST OF THE CWA WITH THE EXCEPTION OF LOCATIONS NORTH OF I-69 AND ESPECIALLY WEST OF US-23 WHERE MID-LEVEL COOLING AND FORCING WILL BE MAXIMIZED. WITH THE LINE ALREADY MARCHING TOWARD THIS AREA, EXPECT THAT THE ABUNDANCE OF MID-LEVEL DRY AIR AND UNIDIRECTIONAL FLOW ABOVE 1.5KM WILL SUPPORT BOWING SEGMENTS CARRYING A LOW-END SEVERE WIND THREAT. IN ADDITION, ISOLATED TORNADO THREAT OUTLINED IN THE EARLIER UPDATE REMAINS IN TACT. FOR REMAINING AREAS, EXPECT NOTHING MORE THAN A GUST TO 40 MPH. IN ADDITION, BACKED OFF ON POPS AS EARLIER SUSPICIONS REGARDING COVERAGE POTENTIAL STILL LOOM. A WEAK COLD FRONT WILL SAG THROUGH THE AREA TONIGHT. FRONTAL INVERSION WILL PROMOTE EXPANSION OF STRATUS LATE TONIGHT, BUT EXPECT THAT MOISTURE WILL BE TOO SHALLOW AND FORCING TOO WEAK TO SUPPORT ANY LEGITIMATE COVERAGE OR INTENSITY OF SHOWERS. WITH UPPER SUPPORT IN THE FORM OF A SHEARING SHORTWAVE NOT SCHEDULED TO ARRIVE UNTIL TUESDAY MORNING PER 12Z GUIDANCE, AND MAINLY SOUTH OF THE AREA AT THAT, NOTHING MORE THAN A CHC POP IS WARRANTED ATTM. && .LONG TERM...TUESDAY THROUGH NEXT MONDAY A COLD FRONT WILL BE SOUTHEAST OF THE CWA TO START OUT TUESDAY MORNING. HOWEVER A MID LEVEL SHORTWAVE RIDING NORTHEAST ALONG THE FRONT WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS TO THE AREA TUESDAY MORNING. AFTER THE SHORTWAVE TRACKS OFF TO THE NORTHEAST SIGNIFICANT DRYING WILL TAKE PLACE AS A SLUG OF 30 PERCENT RELATIVE HUMIDITY AT 700 MB ADVECTS IN FROM THE WEST...ENDING RAIN CHANCES QUICKLY EARLY TUESDAY AFTERNOON. WHILE THERE IS STILL SOME UNCERTAINTY REGARDING HOW FAR WEST THE RAIN WILL FALL GIVEN THE PUSH OF DRY AIR ADVECTING IN...THE LATEST SUITE OF MODELS HAS THE DRIER AIR PUSHING IN A BIT SOONER THAN THE 00Z RUNS. THEREFORE WILL NUDGE THE FORECAST A BIT DRIER TUESDAY AFTERNOON FROM THE PREVIOUS FORECAST. DESPITE THE PASSAGE OF A COLD FRONT THERE ISN`T A LARGE PUSH OF COLD AIR ASSOCIATED WITH IT...MEANING DAYTIME HIGHS ARE EXPECTED TO GET AROUND 80 TUESDAY AFTERNOON BEHIND THE FRONT. RIDGING WILL KEEP THE FORECAST DRY THROUGH WEDNESDAY AS REBOUNDING HEIGHTS ALLOW DAYTIME HIGHS TO GET BACK INTO THE LOWER 80S BY WEDNESDAY AFTERNOON. MOISTURE SURGE FROM THE GULF OF MEXICO COMMENCES ON THURSDAY AS A LOW CHANCE FOR CONVECTION EXISTS WITHIN THE WARM SECTOR OF A REGION-WIDE LOW PRESSURE SYSTEM. BEST CHANCE FOR THUNDERSTORMS /POSSIBLY SEVERE/ WILL BE FRIDAY AS WARM AND MOIST AIRMASS (85/70 T/TD) IS IN PLACE ALONG WITH FORECASTED CAPE OF 3000 J/KG. BULK SHEAR INCREASES TO NEAR 30 KT IN THE 1-6 KM LAYER AS WELL. THESE INGREDIENTS WILL BE IN PLACE AS A RAGGED COLD FRONT CROSSES THE STATE. THIS BRINGS A TRIPLE THREAT OF SEVERE WEATHER WITH WIND...HAIL...AND ISOLATED TORNADOES ALL POSSIBLE && .MARINE... SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH THE CENTRAL GREAT LAKES TONIGHT AS A COLD FRONT MOVES THROUGH LAKE HURON AND LOWER MICHIGAN. SOME OF THESE STORMS MAY BE SEVERE...MAINLY ACROSS THE NORTHERN PORTION OF LAKE HURON. HIGH PRESSURE WILL BUILD INTO THE REGION BEHIND THIS FRONT ON TUESDAY...WHICH WILL REMAIN IN CONTROL OF THE WEATHER THROUGH THURSDAY...PROVIDING FAVORABLE BOATING CONDITIONS. && .AVIATION...ISSUED 114 PM EDT MON SEP 1 2014 //DISCUSSION... LOW STRATUS CONTINUES TO MIX UP TO LOW VFR DIURNALLY FORCED CU. EXPECT THIS TREND TO CONTINUE THROUGH THE NEAR TERM. ATTENTION THEN TURNS TOWARD TSTORM CHANCES THIS AFTERNOON. CAPPING WILL LIMIT POTENTIAL SOUTH OF KPTK SO TSHRA WAS REMOVED FOR THESE LOCATIONS AS THE PROBABILITY IS NOW TOO LOW TO WARRANT A MENTION IN THE TAFS. EXPECTATIONS REMAIN UNCHANGED FROM KFNT NORTH UPSTREAM ACTIVITY IS MORE CERTAIN TO MOVE IN THIS AFTERNOON. LOW CLOUDS AND PERHAPS A VISIBILITY RESTRICTION WILL BE POSSIBLE BEHIND THE FRONT LATE TONIGHT BUT ONCE AGAIN EXPECT PRECIP POTENTIAL TO REMAIN RATHER LOW WITH THE BULK OF 12Z GUIDANCE HOLDING ACTIVITY SOUTH OF THE MICHIGAN BORDER. FOR DTW...ALTHOUGH CONFIDENCE IN TSTORMS HAS DECREASED...IT AT LEAST REMAINS PLAUSIBLE. THE BEST TIME FOR A THUNDERSTORM TO IMPACT THE AIRPORT WILL BE 21Z-23Z THIS AFTERNOON. CONFIDENCE IN SHOWER COVERAGE TOWARD MORNING IS ALSO QUITE LOW. ELECTED TO ELIMINATE SPECIFIC MENTION FROM THE TAF UNTIL POTENTIALLY IMPACTED AREA BECOMES MORE CLEAR. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILINGS BELOW 5KFT THIS AFTERNOON AND LATE TONIGHT * LOW CONFIDENCE THAT A TSTORM WILL IMPACT KDTW && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...JVC LONG TERM....KURIMSKI/MM MARINE.......KURIMSKI AVIATION.....JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
127 PM EDT MON SEP 1 2014 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 330 AM EDT MON SEP 1 2014 A COLD FRONT WILL MOVE INTO THE GREAT LAKES REGION FROM THE WEST LATER TODAY AND INTO TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER SOUTHWEST LOWER MICHIGAN FROM THE LATE MORNING HOURS PERSISTING INTO THE EVENING. SOME OF THE STORMS FROM THE MIDDAY HOURS THROUGH THE EVENING MAY BE SEVERE WITH LARGE HAIL AND STRONG WINDS. SHOWERS AND STORMS WILL GRADUALLY TAPER OFF TONIGHT FROM NORTH TO SOUTH AS THE FRONT DROPS SOUTHWARD INTO INDIANA. DRY WEATHER IS THEN EXPECTED FOR THE MOST PART FROM TUESDAY THROUGH WEDNESDAY. CHANCES FOR SHOWERS AND STORMS INCREASE ONCE AGAIN WEDNESDAY NIGHT THROUGH FRIDAY AS A LOW PRESSURE SYSTEM TRAVERSES THE AREA. TEMPERATURES THIS WEEK WILL BE NEAR TO ABOVE NORMAL WITH HIGHS IN THE UPPER 70S TO 80S ALL WEEK. A COOL DOWN IS EXPECTED NEXT WEEKEND BEHIND A COLD FRONT THAT MOVES THROUGH ON FRIDAY. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 1100 AM EDT MON SEP 1 2014 ISOLATED SEVERE WEATHER THREAT CONTINUES THIS AFTERNOON (2PM - 8PM) EAST OF U.S. 131 WITH DAMAGING WIND GUSTS THE MAIN THREAT. BRIEF LOCALIZED FLOODING TYPICAL OF STRONG THUNDERSTORMS IS ALSO POSSIBLE. APPROACHING WEAK FRONTAL BOUNDARY...SEPARATING DEWPOINTS IN THE LOW 70S FROM THOSE IN THE MID 60S...IS CURRENTLY ORIENTED NORTH-SOUTH ACROSS EASTERN WISCONSIN AND ILLINOIS. THERE IS ALSO CONSIDERABLE CLOUDINESS ALONG AND AHEAD OF FRONT WHICH IS TEMPERATURES AND DESTABILIZATION OFTHE AIRMASS. THE FRONT WILL SWEEP EASTWARD ACROSS THE CWA THIS AFTERNOON AND EARLY EVENING PROVIDING LOW LEVEL LIFT AND POTENTIAL FOCUS FOR DEVELOPMENT OF NEW STORMS. ALOFT HOWEVER...THE LEAD SHORTWAVE AND NOSE OF UPPER JET WILL PUSH EASTWARD OVER THE REGION WITH BEST DEEP LIFT NORTH MAINLY NORTH OF THE AREA. INSTABILITY AND WIND FIELDS ARE FAVORABLE FOR SEVERE STORMS WITH CAPE VALUES OF 500 - 1500 J/KG...0-6 KM BULK SHEAR VALUES NEAR 40 KTS...AND 0-1KM SHEAR VALUES AROUND 20 KTS. HOWEVER...LACK OF DEEP LIFT WILL LIMIT COVERAGE OF STORMS AND OVERALL SEVERE THEAT SIGNICANTLY. THIS SOLUTION IS REFLECTED IN MANY OF THE HIGHER RESOLUTION CONVECTION ALLOWING MODELS INCLUDING LAST FEW NSSL WRF AND HRRR RUNS. OTHERWISE...THE SHORT TERM IS RELATIVELY QUIET. ANY STORMS THIS EVENING SHOULD WORK SOUTH OF THE AREA OVERNIGHT. NOT OUT OF THE REALM OF POSSIBILITIES FOR A FEW SHOWERS ON TUESDAY...BUT FELT THE THREAT WAS SMALL ENOUGH TO GO DRY. TUESDAY NIGHT AND WEDNESDAY SHOULD BE DRY WITH RIDGING IN PLACE AT THE SURFACE. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM EDT MON SEP 1 2014 THE MOST UNSETTLED WEATHER IN THE LONG TERM LOOKS TO OCCUR IN THE FIRST COUPLE OF DAYS...FROM THE BEGINNING OF THE PERIOD WED NIGHT INTO FRI NIGHT. THE LATEST TREND IS FOR A LITTLE MORE POSSIBLE PCPN WED NIGHT INTO THU WITH THE PASSAGE OF THE WARM FRONT THROUGH THE AREA. THIS LOOKS TO BE THE CASE DUE TO THE GRADIENT/LOW LEVEL JET EXPECTED TO BE A LITTLE STRONGER WITH A STRONGER TROUGH MOVING IN. HOW QUICKLY THE FRONT MOVES THROUGH WILL DICTATE HOW WARM WE GET ON THU. IF THE FRONT MOVES QUICK ENOUGH...WE COULD HAVE A CHC TO WARM TOWARD 90 WITH H850 TEMPS OF 20C ADVECTING IN. FOR NOW...WE HAVE SETTLED WITH THE MID-UPPER 80S WITH THE UNCERTAINTY OF THE PCPN. WE WILL SEE ANOTHER BATCH OF CONVECTION BE POSSIBLE THEN CENTERED AROUND FRI AS THE COLD FRONT PUSHES THROUGH AND ENCOUNTERING THE VERY WARM AND MOIST AIR MASS. WE COULD HAVE SOME ASSISTANCE VIA THE RRQ OF AN UPPER JET TO OUR N/NE THAT WOULD SUPPLEMENT THE COLD FRONTAL PASSAGE. THE REMAINDER OF THE LONG TERM FROM SAT THROUGH SUN LOOKS TO BE RATHER QUIET...YET COOL. WE WILL SEE A CANADIAN AIR MASS FILTER IN BEHIND THE THU/FRI SYSTEM WITH A DECENT NNE LOW LEVEL FLOW USHERING IT IN. THE UPPER FLOW WILL BE FROM THE NW AND A BIT OF A TROUGH WILL BE OVER THE AREA. THE FAR ERN FLANK OF A SFC RIDGE WILL BE BUILDING IN AS THE SYNOPTIC PATTERN OVER THE COUNTRY WILL FEATURE A FAIRLY BROAD/EXPANSIVE UPPER RIDGE FROM THE ERN PACIFIC INTO THE ROCKIES. THIS SHOULD KEEP THE AREA DRY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 122 PM EDT MON SEP 1 2014 A LINE OF SHOWERS AND THUNDERSTORMS WILL CROSS LOWER MICHIGAN THIS AFTERNOON. BRIEF PERIODS OF HEAVY RAINFALL IS POSSIBLE WITH VSBYS FALLING TO IFR/MVFR CONDITIONS. THE ACTUAL COLD FRONT WON/T PASS THROUGH UNTIL AFTER MIDNIGHT. AS A RESULT...WE KEPT MVFR CIGS IN THE TAFS UNTIL AROUND MIDNIGHT. && .MARINE... ISSUED AT 1100 AM EDT MON SEP 1 2014 SCA/BEACH HAZARD WORKING WELL WITHWIND GUSTS NEAR 30 KTS AND WAVE AROUND 4 FT OBSERVED NORTH OF HOLLAND TOWARDS LUDINGTON AT THIS TIME. WINDS WILL CONTINUE NEXT SEVERAL HOURS WITH WAVES UP TO 5 FEET. WINDS / WAVES WILL SUBSIDE QUICKLY LATE THIS AFTERNOON WITH PASSAGE OF FRONT AND SHIFT OF WINDS TO A MORE WESTERLY DIRECTION. THE NEXT POSSIBLE SET OF HEADLINES THAT MAY BE NEEDED FOR THE NEARSHORE WATERS LOOKS TO START IN THE WED NIGHT/THU TIME FRAME AS THE FLOW STRENGTHENS WITH A SURGE OF WARMER AIR WITH THE NEXT FRONTAL SYSTEM POISED TO MOVE IN. && .HYDROLOGY... ISSUED AT 1237 PM EDT MON SEP 1 2014 RIVERS ARE RUNNING A LITTLE ABOVE NORMAL... BUT ARE STILL FAR BELOW BANK FULL. PRECIPITATION THROUGH THIS EVENING IS EXPECTED TO TOTAL AROUND A QUARTER OF AN INCH WITH ISOLATED LOCATIONS NORTHWEST OF GRAND RAPIDS RECEIVING NEARLY AN INCH. THIS SHOULD LEAD TO SMALL RISES ON AREA RIVERS WITH PEAK LEVELS BELOW BANK FULL BY MID WEEK. ADDITIONAL PRECIPITATION IS POSSIBLE WEDNESDAY INTO FRIDAY NIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR MIZ037- 043-050-056-064-071. LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849. && $$ SYNOPSIS...DUKE SHORT TERM...COBB LONG TERM...NJJ AVIATION...93 HYDROLOGY...63 MARINE...COBB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
123 PM EDT MON SEP 1 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT MON SEP 1 2014 WV IMAGERY AND RUC INDICATED A BROAD MID/UPPER LEVEL TROUGH FROM THE ROCKIES INTO THE NRN/CNTRL PLAINS. AT THE SFC...A COLD FRONT EXTENDED FROM NEAR INL THROUGH CNTRL MN INTO NW IA. A WEAK SHRTWV FROM NE MN INTO NW WI SUPPORTED AN AREA OF SHOWERS AND ISOLD TSRA OVER ERN MN INTO NW WI AND LAKE SUPERIOR. A STRONGER SHRTWV WAS LOCATED OVER SW MN INTO NW IA. WITH ONLY MODEST 500-1000 J/KG MUCAPE...ONLY A FEW TSRA WERE NOTED OVER THE REGION. THE MORE ACTIVE CONVECTION OVER ERN LAKE SUPERIOR WAS ASSOCIATED WITH AN AREA OF STRONGER 850 THETA-E ADVECTION AT THE NOSE OF THE LLJ. TODAY...AS THE NW IA SHRTWV LIFTS TOWARD THE AREA WITH MODERATE 700-300 MB QVECTOR CONV AND THE COLD FRONT APPROACHES THE AREA...EXPECT SHRA/TSRA COVERAGE TO INCREASE THIS MORNING. EVEN WITH 0-1KM/0-6KM SHEAR AROUND 40 KNOTS...SINCE INSTABILITY WILL REMAIN LIMITED...MAINLY JUST BRIEF HEAVY RAIN IS EXPECTED. OVERALL RAINFALL AMOUNTS SHOULD BE LIMITED GIVEN THE QUICK MOVEMENT OF THE CONVECTIVE CELLS AND LACK OF LARGE SCALE ORGANIZATION. THE PCPN WILL DIMINISH FROM WEST TO EAST THIS AFTERNOON AS THE COLD FRONT MOVES THROUGH AND QVECTOR DIV SPREADS INTO UPPER MI IN THE WAKE OF THE SHRTWV. CLOUD COVER WILL KEEP HIGH TEMPS NEAR OR SLIGHTLY BELOW SEASONAL AVERAGES IN THE UPPER 60S TO AROUND 70. TONIGHT...ANY LINGERING PCPN OVER THE ERN CWA IN THE EVENING WILL END EARLY. OTHERWISE...A DRIER AIRMASS MOVING INTO THE AREA WITH DEWPOINTS DROPPING TOWARD THE LOWER 50S WILL ALLOW TEMPS TO ALSO DROP INTO THE LOWER TO MID 50S AS SKIES PARTIALLY CLEAR. AN INCREASE IN CLOUD COVER IS EXPECTED LATE OVER THE SW CWA AHEAD OF THE NEXT WEAK SHRTWV. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 321 AM EDT MON SEP 1 2014 IN THE WAKE OF STRONGER SHORTWAVE AND SFC FRONT MOVING THROUGH TODAY...ANOTHER SHORTWAVE CLIPS ACROSS THE AREA ON TUESDAY IN INCREASINGLY ZONAL FLOW ALOFT. MOISTURE IS LIMITED WITH THE WAVE AS SOUNDINGS ONLY SHOW MOISTURE H8-H7. PRETTY HIGH BASED SHRA AND WILL ALSO MENTION ISOLD TSRA WITH MLCAPE 500-1000 J/KG PER ECMWF AND GFS. WILL INCLUDE SLIGHT CHANCE POPS. A LULL FOR TUE NIGHT AS SFC RIDGE MOVES FROM MIDDLE MISSISSIPPI RIVER VALLEY TO THE OHIO VALLEY. LGT SW WINDS ON PERIFERY OF THE RIDGE WILL LIMIT COOLING. LOWEST PWAT FAR EAST CWA WHERE MIN TEMPS MAY FALL TO AROUND 50 DEGREES. ON WEDNESDAY...GFS AND GEM-NH INDICATE SOME SHOWERS COULD OCCUR IN THE AFTN OVER MAINLY THE WEST HALF CWA. WEAK SHORTWAVE IS THERE BUT ONLY APPEARS THAT BEST MOISTURE INFLOW IS OVER FAR WEST CWA. WARM AIR ADVECTION BOOSTS H85 TEMPS TO AROUND +15C SO AS LONG AS SKIES STAY AT LEAST PARTLY CLOUDY...MAX TEMPS WILL TOP OUT IN THE MID 70S TO LOWER 80S. LATER WEDNESDAY NIGHT INTO THURSDAY MORNING LARGER SCALE LIFT AHEAD OF UPPER TROUGH INCREASES OVER NORTHERN PLAINS AND WESTERN GREAT LAKES. LIKELY WILL BE SOME SHORTWAVES SLIDING OUT OF NORTHERN PLAINS AS WELL...THOUGH RIGHT NOW SIGNAL OF ANY STRONGER SHORTWAVE IS MINIMAL. THERE IS A MID LEVEL JET MAX SLIDING OVER THE AREA AND H85-H5 Q-VECTOR CONVERGENCE WILL BE ON THE INCREASE. PRIMARY SFC TROUGH WILL BE OVER MINNESOTA AND BASED ON SFC WINDS AND DWPNTS...THERE WILL BE A WARM FRONT VCNTY OF SOUTHERN/CENTRAL MINNESOTA INTO WESTERN WISCONSIN. BULGE OF WARMTH ALOFT RESULTS IN AN ELEVATED MIXED LAYER WITH H7-H5 LAPSE RATES OVER 8C/KM MAKING IT OVER UPR LAKES AHEAD OF THE SFC TROUGH. RESERVOIR OF ML MUCAPE OVER 2000J/KG WILL BE JUST SOUTHWEST OF UPR MICHIGAN WITH MID LEVEL FLOW SW-NE. EDGE OF SFC BASED CAPE AND ORIENTATION OF H85-H3 THICKNESSES INDICATE THAT STRONGER STORMS MAY BE MORE TO SOUTHWEST OF UPR MICHIGAN LATER WEDNESDAY NIGHT INTO THURSDAY MORNING. TOUGH TO SAY AT THIS POINT THOUGH. CONSENSUS CHANCE POPS WORK FOR NOW SINCE THERE WILL BE LARGE SCALE WARM AIR ADVECTION AND H85-H7 MOISTURE TRANSPORT AIMED INTO THE AREA. MORE SHRA/TSRA POSSIBLE AS SFC FRONT WORKS ACROSS UPR MICHIGAN LATER ON THURSDAY. PLENTY OF INSTABILITY AS TEMPS IN THE SOUTH-SOUTHWEST FLOW AHEAD OF FRONT SHOULD REACH TOWARD 80 DEGREES WITH EVEN A FEW HOURS OF PARTIAL CLEARING SINCE H85 TEMPS ARE 18-20C. MOISTURE AVAILABILITY/MID LEVEL CAPPING ALONG THE FRONT REMAINS A CONCERN FOR COVERAGE OF SFC BASED STORMS IN THE AFTN. MODELS MAY BE PICKING UP ON THIS AS GFS/ECMWF SHOW A MIN IN QPF 18Z-24Z BUT THEN INCREASE IT BY 06Z ON FRIDAY AS FRONT WILL MAINLY BE SOUTH AND EAST OF CWA BY THAT TIME. NO NEED TO GET TOO FANCY WITH THE GRIDS ATTM GIVEN ALL THE UNCERTAINTY. KEPT WITH THE CONSENSUS CHANCE POPS ON THURSDAY WITH THIS DROPPING OFF TO LOWER CHANCES THURSDAY NIGHT CLOSER TO THE DEPARTING FRONT. REST OF THE FORECAST LOOKS DRY AND COOLER AS HIGH PRESSURE BUILDS IN ON FRIDAY AND WILL HOLD ON THROUGH NEXT WEEKEND. MAX TEMPS IN THE MID 60S TO LOWER 70S. CHILLY LOWS POSSIBLE INLAND BOTH FRIDAY NIGHT AND SATURDAY NIGHT DUE TO THE DRY AIRMASS AND LGT WINDS BENEATH THE HIGH PRESSURE. BIAS CORRECTED GUIDANCES SHOWED MINS IN THE LOWER 40S BUT WOULD NOT BE SURPRISED TO SEE READINGS DIPPING INTO THE 30S EITHER OF THOSE NIGHTS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 122 PM EDT MON SEP 1 2014 IWD...MVFR CONDITIONS WILL PREDOMINATE EARLY BEFORE DRIER AIR MOVES IN AND ALLOWS FOR CONDITIONS TO IMPROVE TO VFR BY THIS EVENING. CMX...CONTINUED -SHRA EARLY SHOULD RESULT IN A PERIOD OF IFR CONDITIONS DURING THE EARLY AFTERNOON BEFORE THE W WIND TAPS DRIER AIR AND RESULTS IN IMPROVEMENT TO VFR THIS EVENING. SAW...SOME SHRA WITH MVFR CONDITIONS WILL CONTINUE WITH THE APPROACH OF A SFC COLD FRONT MOVING THROUGH EARLY THIS PERIOD. EXPECT IMPROVEMENT LATE IN THE AFTERNOON WITH A WSHFT TO A DOWNSLOPE W DIRECTION AND THE ARRIVAL OF DRIER AIR FOLLOWING THE FROPA. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT MON SEP 1 2014 WINDS WILL BE 20 KNOTS OR LESS THROUGH THIS FORECAST PERIOD WITH AREAS OF FOG PERSISTING UNTIL DRIER AIR MOVES INTO THE REGION TONIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
114 PM EDT MON SEP 1 2014 .AVIATION... //DISCUSSION... LOW STRATUS CONTINUES TO MIX UP TO LOW VFR DIURNALLY FORCED CU. EXPECT THIS TREND TO CONTINUE THROUGH THE NEAR TERM. ATTENTION THEN TURNS TOWARD TSTORM CHANCES THIS AFTERNOON. CAPPING WILL LIMIT POTENTIAL SOUTH OF KPTK SO TSHRA WAS REMOVED FOR THESE LOCATIONS AS THE PROBABILITY IS NOW TOO LOW TO WARRANT A MENTION IN THE TAFS. EXPECTATIONS REMAIN UNCHANGED FROM KFNT NORTH UPSTREAM ACTIVITY IS MORE CERTAIN TO MOVE IN THIS AFTERNOON. LOW CLOUDS AND PERHAPS A VISIBILITY RESTRICTION WILL BE POSSIBLE BEHIND THE FRONT LATE TONIGHT BUT ONCE AGAIN EXPECT PRECIP POTENTIAL TO REMAIN RATHER LOW WITH THE BULK OF 12Z GUIDANCE HOLDING ACTIVITY SOUTH OF THE MICHIGAN BORDER. FOR DTW...ALTHOUGH CONFIDENCE IN TSTORMS HAS DECREASED...IT AT LEAST REMAINS PLAUSIBLE. THE BEST TIME FOR A THUNDERSTORM TO IMPACT THE AIRPORT WILL BE 21Z-23Z THIS AFTERNOON. CONFIDENCE IN SHOWER COVERAGE TOWARD MORNING IS ALSO QUITE LOW. ELECTED TO ELIMINATE SPECIFIC MENTION FROM THE TAF UNTIL POTENTIALLY IMPACTED AREA BECOMES MORE CLEAR. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILINGS BELOW 5KFT THIS AFTERNOON AND LATE TONIGHT * LOW CONFIDENCE THAT A TSTORM WILL IMPACT KDTW && .PREV DISCUSSION...ISSUED 1227 PM EDT MON SEP 1 2014 UPDATE... MOST OF SOUTHEAST MICHIGAN REMAINS SHROUDED IN LOW AND MID-LEVEL CLOUDS EARLY THIS AFTERNOON, ALTHOUGH THE LATEST TRENDS ON VISIBLE INDICATE THAT THE STRATUS DECK HAS BEGUN TO EVOLVE TOWARD A DIURNALLY FORCED CU FIELD. AS A RESULT, TEMPERATURES HAVE RISEN INTO THE MID TO UPPER 70S FROM WESTERN LOWER MI NORTHEASTWARD INTO THE THUMB WHILE DEWPOINTS REMAIN LOCKED IN AROUND 70 DEGREES. THE STOUT 600MB CAP INDICATED ON THIS MORNING`S SOUNDING REMAINS THE ONLY IMPEDANCE, ALBEIT A POTENTIALLY SIGNIFICANT ONE, TO WIDESPREAD SEVERE WEATHER THIS AFTERNOON. CAP NOTWITHSTANDING, THERMODYNAMIC PROFILES ARE IMPRESSIVE. MODERATE DESTABILIZATION IS STILL FAVORED GIVEN THE ABUNDANCE OF LOW-LEVEL MOISTURE AND SURFACE TEMPERATURES ALREADY PUSHING UPPER 70S AT NOON. 0-6KM BULK SHEAR FEATURING VEERING THROUGH THE LOWEST 1.5KM AGL AND AFOREMENTIONED DEGREE OF DESTABILIZATION WILL SUPPORT AN INITIAL CONVECTIVE MODE OF SUPERCELLS. ANY SUPERCELLS WILL CARRY TORNADIC POTENTIAL GIVEN FAVORABLE THERMODYNAMIC PROFILES FOR STRETCHING IN THE LOWEST LEVELS, VEERED SFC-1KM WIND PROFILES, AND REASONABLY LOW LCLS OF 700-900M. UNIDIRECTIONAL MID-LEVEL WIND PROFILE AND PLENTY DRY AIR WOULD THEN SUPPORT A QUICK EVOLUTION TOWARD DOWNDRAFT MODULATED CONVECTION AND A CORRESPONDING EVOLUTION TOWARD DYNAMIC BOWS EARLY IN THE CONVECTIVE CYCLE. GIVEN THE HIGH FREEZING LEVELS, THE LACK OF MESOCYCLONE FORCING WITHIN BOWS WILL TEND TO LIMIT THE THREAT TO WIND ONLY. IN SPITE OF THE RIPE ENVIRONMENT, CAPPING LOOMS LARGE. THE 12Z NAM12 ALLOWS ENCROACHING HEIGHT FALLS TO USHER IN SUFFICIENT MID-LEVEL COOLING SUPPORTIVE OF STRONG, DEEP CONVECTION THROUGH THE EARLY/MID AFTERNOON. AT THE SAME TIME, THE LAST SEVERAL RUNS OF THE RAP IS CONSIDERABLY SLOWER COOLING THE COLUMN AND LIMITS ANY SEVERE THREAT TO THE SAGINAW VALLEY AREA WHERE MID-LEVEL COOLING/FORCING WILL BE MAXIMIZED. THE SOLUTION SPACE REMAINS WIDE OPEN AND CONFIDENCE IN SEVERE WX IS CORRESPONDINGLY LOW. AT THIS POINT, EVEN COVERAGE OF CONVECTION SEEMS TO BE IN QUESTION, PARTICULARLY IF THE LATEST NON NAM GUIDANCE IS TO BE BELIEVED. IN PURSUIT OF CLARITY, AN 18Z SOUNDING IS FORTHCOMING. PREV DISCUSSION...ISSUED 405 AM EDT MON SEP 1 2014 SHORT TERM... TODAY AND TONIGHT THUNDERSTORMS AND THE POTENTIAL FOR SEVERE WEATHER WILL BE THE PRIMARY SUBJECT OF THE FORECAST FOR TODAY AND TONIGHT AS INGREDIENTS COME TOGETHER FOR AN ACTIVE AFTERNOON AND EVENING AROUND SE MICHIGAN. A FEW ELEVATED SHOWERS OR WEAK THUNDERSTORMS WILL BE POSSIBLE DURING THE MORNING AS THE WARM SECTOR OF THE BROAD LOW PRESSURE SYSTEM BUILDS INTO LOWER MICHIGAN. EXPECT THIS TO BE FOLLOWED BY SURFACE BASED STORMS LIKELY INITIATING IN THE LEE OF LAKE MICHIGAN EARLY TO MID AFTERNOON AND PROGRESSING THROUGH SE MICHIGAN AS THE LEADING EDGE OF THE UPPER WAVE/MCV REMNANTS INTERACT WITH THE LOW LEVEL MOISTURE AXIS DURING PEAK HEATING. A SECOND ROUND OF STORMS IS THEN LIKELY TO INITIATE ALONG AND AHEAD OF THE COLD FRONT AND FOLLOW THE AFTERNOON STORMS THROUGH OUR AREA MID EVENING THROUGH THE OVERNIGHT. EARLY MORNING IR SATELLITE IMAGERY INDICATES STRONGLY WARMING CLOUD TOPS ASSOCIATED WITH THE UPSTREAM CONVECTION WHICH SUPPORTS THE DISSIPATING TREND ADVERTISED IN MODEL DATA AND THE SCENARIO OF NEW DEVELOPMENT OVER LOWER MICHIGAN DURING THE DAY. THIS DISSIPATING TREND IS HAPPENING SOON ENOUGH TO ALLOW DEBRIS CLOUDS TO ERODE AND/OR GET CARRIED TO OUR WEST AND NORTH BY THE SOUTHWEST FLOW ALOFT. THAT LEAVES JUST PATCHY MID CLOUDS...ALONG WITH AREAS OF FOG AND LOW STRATUS...AS A MINIMAL OBSTRUCTION TO STRONG SURFACE HEATING TO START THE DAY. IT THEN SEEMS REASONABLE TO ASSUME MAX TEMPS OF 80-85 WILL BE REACHABLE WITH SURFACE DEWPOINT AROUND 70 CARRYING 0-1KM LAYER CAPE TOWARD 1500 J/KG. A SURFACE PARCEL AT 85/72 GENERATES SURFACE BASED CAPE NEAR 2500 J/KG AS A WORST CASE SCENARIO. THESE VALUES ARE PLENTY HIGH ENOUGH TO INTERACT WITH A STRENGTHENING UNIDIRECTIONAL WIND PROFILE INCREASING TO NEAR 40 KNOTS OF BULK SHEAR IN THE 0-6KM LAYER...WITH MOST OF THAT IN THE 0-3KM LAYER. THIS WILL ALLOW DISCRETE CELLS TO DEVELOP SUPERCELL CHARACTER EARLY ON WITH SPLITS AND MERGERS GROWING UPSCALE INTO LINEAR SEGMENTS AS CONVECTION MATURES LATE AFTERNOON INTO EARLY EVENING. DAMAGING WIND WILL BE THE PRIMARY HAZARD. LARGE HAIL WILL BE POSSIBLE BUT LIKELY LIMITED TO ONLY THE STRONGEST MESO ENHANCED UPDRAFTS DUE TO HIGH FREEZING LEVEL. IT IS ALSO IMPORTANT TO NOTE THAT MODEL SOUNDINGS INDICATE CAPE EXCEEDING 300 J/KG IN THE LOWEST 3 KM ALONG WITH 0-3 KM HELICITY AROUND 200 M2/S2 AND LCL BETWEEN 3500 AND 4000 FT. THESE ARE FAVORABLE PARAMETERS FOR TORNADOGENESIS. ROUND TWO OF STORMS WILL BE TRIGGERED BY THE COLD FRONT WEST OF LAKE MICHIGAN DURING THE LATE AFTERNOON. SEVERE POTENTIAL WITH THIS ACTIVITY WILL BE LOWER BY THE TIME IT REACHES OUR AREA TOWARD LATE EVENING INTO THE OVERNIGHT...BOTH DUE TO THE DOWNSIDE OF DAYTIME HEATING AND THE PRECEDING STORMS. HEAVY RAINFALL MAY END UP BEING THE MAIN CONCERN AS THE THE SLOW MOVING COLD FRONT ENDS UP THE FOCUS OF LARGE SCALE SUPPORT FROM THE ENTRANCE REGION OF THE UPPER JET AND CONTINUED LOW LEVEL MOISTURE TRANSPORT. THIS WILL DEPEND ON HOW MUCH POST FRONTAL/ELEVATED CONVECTION IS ABLE TO OCCUR WHICH THE MODELS SUGGEST WILL BE MINIMAL...INSTEAD FOCUSING ADDITIONAL RAINFALL ALONG AND AHEAD OF THE FRONT THROUGH SUNRISE TUESDAY. LONG TERM... WARMER/ABOVE NORMAL TEMPERATURES APPEAR TO BE IN STORE FOR THE FIRST SEVERAL DAYS OF SEPTEMBER. BROAD UPPER LEVEL TROUGH WILL BE SWINGING THROUGH THE CENTRAL GREAT LAKES ON TUESDAY...AND IT APPEARS THE SURFACE COLD FRONT/MOISTURE AXIS WILL HAVE CLEARED SOUTHEAST MICHIGAN AROUND 12Z TUESDAY...WITH A DRAMATIC DRYING TREND TAKING PLACE AS PW VALUES AROUND 2 INCHES NEAR THE OHIO BORDER ARE JUST ABOUT CUT IN HALF TO AROUND 1 INCH. HOWEVER...THERE IS AN EMBEDDED STRONG SHORTWAVE QUICKLY TRACKING OUT OF EASTERN IOWA EARLY TUESDAY MORNING...AND NEED TO ACCOUNT FOR THE POSSIBILITY OF THE FLOW OUT AHEAD OF THIS FEATURE A BIT MORE BACKED...SLOWING THE PROGRESS OF THE FRONTAL BOUNDARY TO THE SOUTH...AND CARRY LOW CHANCE POPS...AS DAYTIME SURFACE BASED INSTABILITY SETS IN AS WELL...WITH AROUND 1000 J/KG TO WORK WITH PER 00Z NAM. ALTHOUGH...THE 00Z GFS IS DRIER AND DECIDEDLY MORE ANTICYCLONIC AT THE SURFACE...WHILE THE CANADIAN IS THE WETTEST. SHORT LIVED ENERGETIC ZONAL FLOW OVER THE NORTHERN CONUS TUESDAY NIGHT WITH STRONGER UPPER WAVE DIVING SOUTHEAST THROUGH THE PACIFIC NORTHWEST. HEIGHTS WILL REBOUND OVER THE EASTERN CONUS WEDNESDAY/THURSDAY WITH FAVORABLE DEEP SOUTHWEST FLOW AROUND SURFACE HIGH CENTERED OVER THE EASTERN SEABOARD. HIGHS THE 80S APPEAR IN THE OFFING...AS 850 MB TEMPS RISE TOWARD 20 C ON THURSDAY...AND REACH OR POSSIBLY SLIGHTLY EXCEED 20 C ON FRIDAY...WHICH MAKES A RUN TOWARD A 90 DEGREE DAY A REAL POSSIBILITY. HOWEVER...A COLD FRONT WILL PROBABLY ALREADY BE ARRIVING...SUPPORTING CLOUDS AND A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS...WHICH OF COURSE WOULD HINDER MAXES. MUCH LOWER CHANCE OF PRECIPITATION ON THURSDAY AS WARM FRONT LIFTS THROUGH THE WESTERN GREAT LAKES. MARINE... SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...AND CONTINUE TONIGHT AS A COLD FRONT MOVES THROUGH LAKE HURON AND LOWER MICHIGAN. SOME OF THESE STORMS MAY BE SEVERE. HIGH PRESSURE WILL BUILD INTO THE REGION BEHIND THIS FRONT ON TUESDAY...WHICH WILL REMAIN IN CONTROL OF THE WEATHER THROUGH THURSDAY...PROVIDING FAVORABLE BOATING CONDITIONS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....JVC UPDATE.......JVC SHORT TERM...BT LONG TERM....SF MARINE.......SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1237 PM EDT MON SEP 1 2014 LATEST UPDATE... HYDRO .SYNOPSIS... ISSUED AT 330 AM EDT MON SEP 1 2014 A COLD FRONT WILL MOVE INTO THE GREAT LAKES REGION FROM THE WEST LATER TODAY AND INTO TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER SOUTHWEST LOWER MICHIGAN FROM THE LATE MORNING HOURS PERSISTING INTO THE EVENING. SOME OF THE STORMS FROM THE MIDDAY HOURS THROUGH THE EVENING MAY BE SEVERE WITH LARGE HAIL AND STRONG WINDS. SHOWERS AND STORMS WILL GRADUALLY TAPER OFF TONIGHT FROM NORTH TO SOUTH AS THE FRONT DROPS SOUTHWARD INTO INDIANA. DRY WEATHER IS THEN EXPECTED FOR THE MOST PART FROM TUESDAY THROUGH WEDNESDAY. CHANCES FOR SHOWERS AND STORMS INCREASE ONCE AGAIN WEDNESDAY NIGHT THROUGH FRIDAY AS A LOW PRESSURE SYSTEM TRAVERSES THE AREA. TEMPERATURES THIS WEEK WILL BE NEAR TO ABOVE NORMAL WITH HIGHS IN THE UPPER 70S TO 80S ALL WEEK. A COOL DOWN IS EXPECTED NEXT WEEKEND BEHIND A COLD FRONT THAT MOVES THROUGH ON FRIDAY. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 1100 AM EDT MON SEP 1 2014 ISOLATED SEVERE WEATHER THREAT CONTINUES THIS AFTERNOON (2PM - 8PM) EAST OF U.S. 131 WITH DAMAGING WIND GUSTS THE MAIN THREAT. BRIEF LOCALIZED FLOODING TYPICAL OF STRONG THUNDERSTORMS IS ALSO POSSIBLE. APPROACHING WEAK FRONTAL BOUNDARY...SEPARATING DEWPOINTS IN THE LOW 70S FROM THOSE IN THE MID 60S...IS CURRENTLY ORIENTED NORTH-SOUTH ACROSS EASTERN WISCONSIN AND ILLINOIS. THERE IS ALSO CONSIDERABLE CLOUDINESS ALONG AND AHEAD OF FRONT WHICH IS TEMPERATURES AND DESTABILIZATION OFTHE AIRMASS. THE FRONT WILL SWEEP EASTWARD ACROSS THE CWA THIS AFTERNOON AND EARLY EVENING PROVIDING LOW LEVEL LIFT AND POTENTIAL FOCUS FOR DEVELOPMENT OF NEW STORMS. ALOFT HOWEVER...THE LEAD SHORTWAVE AND NOSE OF UPPER JET WILL PUSH EASTWARD OVER THE REGION WITH BEST DEEP LIFT NORTH MAINLY NORTH OF THE AREA. INSTABILITY AND WIND FIELDS ARE FAVORABLE FOR SEVERE STORMS WITH CAPE VALUES OF 500 - 1500 J/KG...0-6 KM BULK SHEAR VALUES NEAR 40 KTS...AND 0-1KM SHEAR VALUES AROUND 20 KTS. HOWEVER...LACK OF DEEP LIFT WILL LIMIT COVERAGE OF STORMS AND OVERALL SEVERE THEAT SIGNICANTLY. THIS SOLUTION IS REFLECTED IN MANY OF THE HIGHER RESOLUTION CONVECTION ALLOWING MODELS INCLUDING LAST FEW NSSL WRF AND HRRR RUNS. OTHERWISE...THE SHORT TERM IS RELATIVELY QUIET. ANY STORMS THIS EVENING SHOULD WORK SOUTH OF THE AREA OVERNIGHT. NOT OUT OF THE REALM OF POSSIBILITIES FOR A FEW SHOWERS ON TUESDAY...BUT FELT THE THREAT WAS SMALL ENOUGH TO GO DRY. TUESDAY NIGHT AND WEDNESDAY SHOULD BE DRY WITH RIDGING IN PLACE AT THE SURFACE. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM EDT MON SEP 1 2014 THE MOST UNSETTLED WEATHER IN THE LONG TERM LOOKS TO OCCUR IN THE FIRST COUPLE OF DAYS...FROM THE BEGINNING OF THE PERIOD WED NIGHT INTO FRI NIGHT. THE LATEST TREND IS FOR A LITTLE MORE POSSIBLE PCPN WED NIGHT INTO THU WITH THE PASSAGE OF THE WARM FRONT THROUGH THE AREA. THIS LOOKS TO BE THE CASE DUE TO THE GRADIENT/LOW LEVEL JET EXPECTED TO BE A LITTLE STRONGER WITH A STRONGER TROUGH MOVING IN. HOW QUICKLY THE FRONT MOVES THROUGH WILL DICTATE HOW WARM WE GET ON THU. IF THE FRONT MOVES QUICK ENOUGH...WE COULD HAVE A CHC TO WARM TOWARD 90 WITH H850 TEMPS OF 20C ADVECTING IN. FOR NOW...WE HAVE SETTLED WITH THE MID-UPPER 80S WITH THE UNCERTAINTY OF THE PCPN. WE WILL SEE ANOTHER BATCH OF CONVECTION BE POSSIBLE THEN CENTERED AROUND FRI AS THE COLD FRONT PUSHES THROUGH AND ENCOUNTERING THE VERY WARM AND MOIST AIR MASS. WE COULD HAVE SOME ASSISTANCE VIA THE RRQ OF AN UPPER JET TO OUR N/NE THAT WOULD SUPPLEMENT THE COLD FRONTAL PASSAGE. THE REMAINDER OF THE LONG TERM FROM SAT THROUGH SUN LOOKS TO BE RATHER QUIET...YET COOL. WE WILL SEE A CANADIAN AIR MASS FILTER IN BEHIND THE THU/FRI SYSTEM WITH A DECENT NNE LOW LEVEL FLOW USHERING IT IN. THE UPPER FLOW WILL BE FROM THE NW AND A BIT OF A TROUGH WILL BE OVER THE AREA. THE FAR ERN FLANK OF A SFC RIDGE WILL BE BUILDING IN AS THE SYNOPTIC PATTERN OVER THE COUNTRY WILL FEATURE A FAIRLY BROAD/EXPANSIVE UPPER RIDGE FROM THE ERN PACIFIC INTO THE ROCKIES. THIS SHOULD KEEP THE AREA DRY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 749 AM EDT MON SEP 1 2014 COMPLICATED WEATHER SCENARIO IN PLACE THIS MORNING WITH STRATUS MOVING NORTH THROUGH THE TAF SITES AND THE POTENTIAL FOR THUNDERSTORMS LOOMING. THE STRATUS AND FOG SHOULD GRADUALLY LIFT THROUGH THE COURSE OF THE MORNING...BUT IT HAS BECOME FAIRLY EXTENSIVE ACROSS SOUTHERN LOWER MICHIGAN. BY AFTERNOON...EXPECTING VFR CEILINGS AND VSBYS OUTSIDE OF THUNDERSTORMS. AS FOR THUNDERSTORMS...THEY ARE ALREADY DEVELOPING ACROSS PORTIONS OF NORTHERN ILLINOIS AND NORTHERN INDIANA. THE TREND SHOULD BE FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE THROUGH THE TAF SITES FROM 14Z OR SO THROUGH 23Z. TOO DIFFICULT TO NAIL DOWN PREVAILING TIMING AT THIS POINT GIVEN THE HIT OR MISS NATURE TO TODAY/S STORMS...SO HAVE VCTS WORDING IN ALL THE TAFS THIS AFTERNOON. OVERNIGHT...EXPECTING THE SHOWERS AND STORMS TO END WITH MVFR CEILINGS TRYING TO SETTLE BACK IN. IT WILL BECOME WINDY TODAY OUT OF THE SOUTH-SOUTHWEST...ESPECIALLY FROM 15Z-23Z. WINDS FROM 200-220 AT 15-25 KNOTS SHOULD BE COMMON. && .MARINE... ISSUED AT 1100 AM EDT MON SEP 1 2014 SCA/BEACH HAZARD WORKING WELL WITHWIND GUSTS NEAR 30 KTS AND WAVE AROUND 4 FT OBSERVED NORTH OF HOLLAND TOWARDS LUDINGTON AT THIS TIME. WINDS WILL CONTINUE NEXT SEVERAL HOURS WITH WAVES UP TO 5 FEET. WINDS / WAVES WILL SUBSIDE QUICKLY LATE THIS AFTERNOON WITH PASSAGE OF FRONT AND SHIFT OF WINDS TO A MORE WESTERLY DIRECTION. THE NEXT POSSIBLE SET OF HEADLINES THAT MAY BE NEEDED FOR THE NEARSHORE WATERS LOOKS TO START IN THE WED NIGHT/THU TIME FRAME AS THE FLOW STRENGTHENS WITH A SURGE OF WARMER AIR WITH THE NEXT FRONTAL SYSTEM POISED TO MOVE IN. && .HYDROLOGY... ISSUED AT 1237 PM EDT MON SEP 1 2014 RIVERS ARE RUNNING A LITTLE ABOVE NORMAL... BUT ARE STILL FAR BELOW BANK FULL. PRECIPITATION THROUGH THIS EVENING IS EXPECTED TO TOTAL AROUND A QUARTER OF AN INCH WITH ISOLATED LOCATIONS NORTHWEST OF GRAND RAPIDS RECEIVING NEARLY AN INCH. THIS SHOULD LEAD TO SMALL RISES ON AREA RIVERS WITH PEAK LEVELS BELOW BANK FULL BY MID WEEK. ADDITIONAL PRECIPITATION IS POSSIBLE WEDNESDAY INTO FRIDAY NIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR MIZ037- 043-050-056-064-071. LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849. && $$ SYNOPSIS...DUKE SHORT TERM...COBB LONG TERM...NJJ AVIATION...DUKE HYDROLOGY...63 MARINE...COBB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1227 PM EDT MON SEP 1 2014 .UPDATE... MOST OF SOUTHEAST MICHIGAN REMAINS SHROUDED IN LOW AND MID-LEVEL CLOUDS EARLY THIS AFTERNOON, ALTHOUGH THE LATEST TRENDS ON VISIBLE INDICATE THAT THE STRATUS DECK HAS BEGUN TO EVOLVE TOWARD A DIURNALLY FORCED CU FIELD. AS A RESULT, TEMPERATURES HAVE RISEN INTO THE MID TO UPPER 70S FROM WESTERN LOWER MI NORTHEASTWARD INTO THE THUMB WHILE DEWPOINTS REMAIN LOCKED IN AROUND 70 DEGREES. THE STOUT 600MB CAP INDICATED ON THIS MORNING`S SOUNDING REMAINS THE ONLY IMPEDANCE, ALBEIT A POTENTIALLY SIGNIFICANT ONE, TO WIDESPREAD SEVERE WEATHER THIS AFTERNOON. CAP NOTWITHSTANDING, THERMODYNAMIC PROFILES ARE IMPRESSIVE. MODERATE DESTABILIZATION IS STILL FAVORED GIVEN THE ABUNDANCE OF LOW-LEVEL MOISTURE AND SURFACE TEMPERATURES ALREADY PUSHING UPPER 70S AT NOON. 0-6KM BULK SHEAR FEATURING VEERING THROUGH THE LOWEST 1.5KM AGL AND AFOREMENTIONED DEGREE OF DESTABILIZATION WILL SUPPORT AN INITIAL CONVECTIVE MODE OF SUPERCELLS. ANY SUPERCELLS WILL CARRY TORNADIC POTENTIAL GIVEN FAVORABLE THERMODYNAMIC PROFILES FOR STRETCHING IN THE LOWEST LEVELS, VEERED SFC-1KM WIND PROFILES, AND REASONABLY LOW LCLS OF 700-900M. UNIDIRECTIONAL MID-LEVEL WIND PROFILE AND PLENTY DRY AIR WOULD THEN SUPPORT A QUICK EVOLUTION TOWARD DOWNDRAFT MODULATED CONVECTION AND A CORRESPONDING EVOLUTION TOWARD DYNAMIC BOWS EARLY IN THE CONVECTIVE CYCLE. GIVEN THE HIGH FREEZING LEVELS, THE LACK OF MESOCYCLONE FORCING WITHIN BOWS WILL TEND TO LIMIT THE THREAT TO WIND ONLY. IN SPITE OF THE RIPE ENVIRONMENT, CAPPING LOOMS LARGE. THE 12Z NAM12 ALLOWS ENCROACHING HEIGHT FALLS TO USHER IN SUFFICIENT MID-LEVEL COOLING SUPPORTIVE OF STRONG, DEEP CONVECTION THROUGH THE EARLY/MID AFTERNOON. AT THE SAME TIME, THE LAST SEVERAL RUNS OF THE RAP IS CONSIDERABLY SLOWER COOLING THE COLUMN AND LIMITS ANY SEVERE THREAT TO THE SAGINAW VALLEY AREA WHERE MID-LEVEL COOLING/FORCING WILL BE MAXIMIZED. THE SOLUTION SPACE REMAINS WIDE OPEN AND CONFIDENCE IN SEVERE WX IS CORRESPONDINGLY LOW. AT THIS POINT, EVEN COVERAGE OF CONVECTION SEEMS TO BE IN QUESTION, PARTICULARLY IF THE LATEST NON NAM GUIDANCE IS TO BE BELIEVED. IN PURSUIT OF CLARITY, AN 18Z SOUNDING IS FORTHCOMING. && .AVIATION...ISSUED 703 AM EDT MON SEP 1 2014 //DISCUSSION... FOG AND STRATUS IN THE WARM AND HUMID AIR OVER SE MICHIGAN WILL PRESENT LIFR/IFR CONDITIONS AS THE FIRST CONCERN FOR AVIATION INTERESTS. INCREASING SOUTH TO SOUTHWEST WIND AND SURFACE HEATING WILL HELP LIFT THE FOG AND MIX THE LOW CLOUDS DURING THE MORNING. THUNDERSTORMS WILL THEN BECOME THE MAIN CHALLENGE DURING THE AFTERNOON AND TONIGHT. TWO ROUNDS OF STORMS ARE LIKELY TO AFFECT THE ENTIRE TERMINAL CORRIDOR...FIRST DURING THE MID AFTERNOON TO MID EVENING DURING THE WARMEST PART OF THE DAY...AND THEN FROM LATE EVENING THROUGH THE OVERNIGHT AS A COLD FRONT MOVES SLOWLY ACROSS SE MICHIGAN. THE MAIN AREA OF RAIN WILL BE ON TRACK TO EXIT TO THE SOUTH AND EAST BY SUNRISE TUESDAY LEAVING BEHIND ANOTHER ROUND OF FOG AND STRATUS BEHIND THE COLD FRONT. FOR DTW... A STRAY SHOWER OR THUNDERSTORM WILL BE POSSIBLE DURING THE MORNING AND EARLY AFTERNOON BUT THE MAIN WINDOW FOR STORMS AND POSSIBLE SEVERE WEATHER REMAINS LATE AFTERNOON THROUGH EARLY EVENING FOR DTW. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILING BELOW 5000 FEET DURING THE MORNING. * MEDIUM CONFIDENCE IN THUNDERSTORM TIMING AND COVERAGE. && .PREV DISCUSSION...ISSUED 405 AM EDT MON SEP 1 2014 SHORT TERM... TODAY AND TONIGHT THUNDERSTORMS AND THE POTENTIAL FOR SEVERE WEATHER WILL BE THE PRIMARY SUBJECT OF THE FORECAST FOR TODAY AND TONIGHT AS INGREDIENTS COME TOGETHER FOR AN ACTIVE AFTERNOON AND EVENING AROUND SE MICHIGAN. A FEW ELEVATED SHOWERS OR WEAK THUNDERSTORMS WILL BE POSSIBLE DURING THE MORNING AS THE WARM SECTOR OF THE BROAD LOW PRESSURE SYSTEM BUILDS INTO LOWER MICHIGAN. EXPECT THIS TO BE FOLLOWED BY SURFACE BASED STORMS LIKELY INITIATING IN THE LEE OF LAKE MICHIGAN EARLY TO MID AFTERNOON AND PROGRESSING THROUGH SE MICHIGAN AS THE LEADING EDGE OF THE UPPER WAVE/MCV REMNANTS INTERACT WITH THE LOW LEVEL MOISTURE AXIS DURING PEAK HEATING. A SECOND ROUND OF STORMS IS THEN LIKELY TO INITIATE ALONG AND AHEAD OF THE COLD FRONT AND FOLLOW THE AFTERNOON STORMS THROUGH OUR AREA MID EVENING THROUGH THE OVERNIGHT. EARLY MORNING IR SATELLITE IMAGERY INDICATES STRONGLY WARMING CLOUD TOPS ASSOCIATED WITH THE UPSTREAM CONVECTION WHICH SUPPORTS THE DISSIPATING TREND ADVERTISED IN MODEL DATA AND THE SCENARIO OF NEW DEVELOPMENT OVER LOWER MICHIGAN DURING THE DAY. THIS DISSIPATING TREND IS HAPPENING SOON ENOUGH TO ALLOW DEBRIS CLOUDS TO ERODE AND/OR GET CARRIED TO OUR WEST AND NORTH BY THE SOUTHWEST FLOW ALOFT. THAT LEAVES JUST PATCHY MID CLOUDS...ALONG WITH AREAS OF FOG AND LOW STRATUS...AS A MINIMAL OBSTRUCTION TO STRONG SURFACE HEATING TO START THE DAY. IT THEN SEEMS REASONABLE TO ASSUME MAX TEMPS OF 80-85 WILL BE REACHABLE WITH SURFACE DEWPOINT AROUND 70 CARRYING 0-1KM LAYER CAPE TOWARD 1500 J/KG. A SURFACE PARCEL AT 85/72 GENERATES SURFACE BASED CAPE NEAR 2500 J/KG AS A WORST CASE SCENARIO. THESE VALUES ARE PLENTY HIGH ENOUGH TO INTERACT WITH A STRENGTHENING UNIDIRECTIONAL WIND PROFILE INCREASING TO NEAR 40 KNOTS OF BULK SHEAR IN THE 0-6KM LAYER...WITH MOST OF THAT IN THE 0-3KM LAYER. THIS WILL ALLOW DISCRETE CELLS TO DEVELOP SUPERCELL CHARACTER EARLY ON WITH SPLITS AND MERGERS GROWING UPSCALE INTO LINEAR SEGMENTS AS CONVECTION MATURES LATE AFTERNOON INTO EARLY EVENING. DAMAGING WIND WILL BE THE PRIMARY HAZARD. LARGE HAIL WILL BE POSSIBLE BUT LIKELY LIMITED TO ONLY THE STRONGEST MESO ENHANCED UPDRAFTS DUE TO HIGH FREEZING LEVEL. IT IS ALSO IMPORTANT TO NOTE THAT MODEL SOUNDINGS INDICATE CAPE EXCEEDING 300 J/KG IN THE LOWEST 3 KM ALONG WITH 0-3 KM HELICITY AROUND 200 M2/S2 AND LCL BETWEEN 3500 AND 4000 FT. THESE ARE FAVORABLE PARAMETERS FOR TORNADOGENESIS. ROUND TWO OF STORMS WILL BE TRIGGERED BY THE COLD FRONT WEST OF LAKE MICHIGAN DURING THE LATE AFTERNOON. SEVERE POTENTIAL WITH THIS ACTIVITY WILL BE LOWER BY THE TIME IT REACHES OUR AREA TOWARD LATE EVENING INTO THE OVERNIGHT...BOTH DUE TO THE DOWNSIDE OF DAYTIME HEATING AND THE PRECEDING STORMS. HEAVY RAINFALL MAY END UP BEING THE MAIN CONCERN AS THE THE SLOW MOVING COLD FRONT ENDS UP THE FOCUS OF LARGE SCALE SUPPORT FROM THE ENTRANCE REGION OF THE UPPER JET AND CONTINUED LOW LEVEL MOISTURE TRANSPORT. THIS WILL DEPEND ON HOW MUCH POST FRONTAL/ELEVATED CONVECTION IS ABLE TO OCCUR WHICH THE MODELS SUGGEST WILL BE MINIMAL...INSTEAD FOCUSING ADDITIONAL RAINFALL ALONG AND AHEAD OF THE FRONT THROUGH SUNRISE TUESDAY. LONG TERM... WARMER/ABOVE NORMAL TEMPERATURES APPEAR TO BE IN STORE FOR THE FIRST SEVERAL DAYS OF SEPTEMBER. BROAD UPPER LEVEL TROUGH WILL BE SWINGING THROUGH THE CENTRAL GREAT LAKES ON TUESDAY...AND IT APPEARS THE SURFACE COLD FRONT/MOISTURE AXIS WILL HAVE CLEARED SOUTHEAST MICHIGAN AROUND 12Z TUESDAY...WITH A DRAMATIC DRYING TREND TAKING PLACE AS PW VALUES AROUND 2 INCHES NEAR THE OHIO BORDER ARE JUST ABOUT CUT IN HALF TO AROUND 1 INCH. HOWEVER...THERE IS AN EMBEDDED STRONG SHORTWAVE QUICKLY TRACKING OUT OF EASTERN IOWA EARLY TUESDAY MORNING...AND NEED TO ACCOUNT FOR THE POSSIBILITY OF THE FLOW OUT AHEAD OF THIS FEATURE A BIT MORE BACKED...SLOWING THE PROGRESS OF THE FRONTAL BOUNDARY TO THE SOUTH...AND CARRY LOW CHANCE POPS...AS DAYTIME SURFACE BASED INSTABILITY SETS IN AS WELL...WITH AROUND 1000 J/KG TO WORK WITH PER 00Z NAM. ALTHOUGH...THE 00Z GFS IS DRIER AND DECIDEDLY MORE ANTICYCLONIC AT THE SURFACE...WHILE THE CANADIAN IS THE WETTEST. SHORT LIVED ENERGETIC ZONAL FLOW OVER THE NORTHERN CONUS TUESDAY NIGHT WITH STRONGER UPPER WAVE DIVING SOUTHEAST THROUGH THE PACIFIC NORTHWEST. HEIGHTS WILL REBOUND OVER THE EASTERN CONUS WEDNESDAY/THURSDAY WITH FAVORABLE DEEP SOUTHWEST FLOW AROUND SURFACE HIGH CENTERED OVER THE EASTERN SEABOARD. HIGHS THE 80S APPEAR IN THE OFFING...AS 850 MB TEMPS RISE TOWARD 20 C ON THURSDAY...AND REACH OR POSSIBLY SLIGHTLY EXCEED 20 C ON FRIDAY...WHICH MAKES A RUN TOWARD A 90 DEGREE DAY A REAL POSSIBILITY. HOWEVER...A COLD FRONT WILL PROBABLY ALREADY BE ARRIVING...SUPPORTING CLOUDS AND A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS...WHICH OF COURSE WOULD HINDER MAXES. MUCH LOWER CHANCE OF PRECIPITATION ON THURSDAY AS WARM FRONT LIFTS THROUGH THE WESTERN GREAT LAKES. MARINE... SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...AND CONTINUE TONIGHT AS A COLD FRONT MOVES THROUGH LAKE HURON AND LOWER MICHIGAN. SOME OF THESE STORMS MAY BE SEVERE. HIGH PRESSURE WILL BUILD INTO THE REGION BEHIND THIS FRONT ON TUESDAY...WHICH WILL REMAIN IN CONTROL OF THE WEATHER THROUGH THURSDAY...PROVIDING FAVORABLE BOATING CONDITIONS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......JVC AVIATION.....BT SHORT TERM...BT LONG TERM....SF MARINE.......SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1100 AM EDT MON SEP 1 2014 LATEST UPDATE... SHORT TERM .SYNOPSIS... ISSUED AT 330 AM EDT MON SEP 1 2014 A COLD FRONT WILL MOVE INTO THE GREAT LAKES REGION FROM THE WEST LATER TODAY AND INTO TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER SOUTHWEST LOWER MICHIGAN FROM THE LATE MORNING HOURS PERSISTING INTO THE EVENING. SOME OF THE STORMS FROM THE MIDDAY HOURS THROUGH THE EVENING MAY BE SEVERE WITH LARGE HAIL AND STRONG WINDS. SHOWERS AND STORMS WILL GRADUALLY TAPER OFF TONIGHT FROM NORTH TO SOUTH AS THE FRONT DROPS SOUTHWARD INTO INDIANA. DRY WEATHER IS THEN EXPECTED FOR THE MOST PART FROM TUESDAY THROUGH WEDNESDAY. CHANCES FOR SHOWERS AND STORMS INCREASE ONCE AGAIN WEDNESDAY NIGHT THROUGH FRIDAY AS A LOW PRESSURE SYSTEM TRAVERSES THE AREA. TEMPERATURES THIS WEEK WILL BE NEAR TO ABOVE NORMAL WITH HIGHS IN THE UPPER 70S TO 80S ALL WEEK. A COOL DOWN IS EXPECTED NEXT WEEKEND BEHIND A COLD FRONT THAT MOVES THROUGH ON FRIDAY. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 1100 AM EDT MON SEP 1 2014 ISOLATED SEVERE WEATHER THREAT CONTINUES THIS AFTERNOON (2PM - 8PM) EAST OF U.S. 131 WITH DAMAGING WIND GUSTS THE MAIN THREAT. BRIEF LOCALIZED FLOODING TYPICAL OF STRONG THUNDERSTORMS IS ALSO POSSIBLE. APPROACHING WEAK FRONTAL BOUNDARY...SEPARATING DEWPOINTS IN THE LOW 70S FROM THOSE IN THE MID 60S...IS CURRENTLY ORIENTED NORTH-SOUTH ACROSS EASTERN WISCONSIN AND ILLINOIS. THERE IS ALSO CONSIDERABLE CLOUDINESS ALONG AND AHEAD OF FRONT WHICH IS TEMPERATURES AND DESTABILIZATION OFTHE AIRMASS. THE FRONT WILL SWEEP EASTWARD ACROSS THE CWA THIS AFTERNOON AND EARLY EVENING PROVIDING LOW LEVEL LIFT AND POTENTIAL FOCUS FOR DEVELOPMENT OF NEW STORMS. ALOFT HOWEVER...THE LEAD SHORTWAVE AND NOSE OF UPPER JET WILL PUSH EASTWARD OVER THE REGION WITH BEST DEEP LIFT NORTH MAINLY NORTH OF THE AREA. INSTABILITY AND WIND FIELDS ARE FAVORABLE FOR SEVERE STORMS WITH CAPE VALUES OF 500 - 1500 J/KG...0-6 KM BULK SHEAR VALUES NEAR 40 KTS...AND 0-1KM SHEAR VALUES AROUND 20 KTS. HOWEVER...LACK OF DEEP LIFT WILL LIMIT COVERAGE OF STORMS AND OVERALL SEVERE THEAT SIGNICANTLY. THIS SOLUTION IS REFLECTED IN MANY OF THE HIGHER RESOLUTION CONVECTION ALLOWING MODELS INCLUDING LAST FEW NSSL WRF AND HRRR RUNS. OTHERWISE...THE SHORT TERM IS RELATIVELY QUIET. ANY STORMS THIS EVENING SHOULD WORK SOUTH OF THE AREA OVERNIGHT. NOT OUT OF THE REALM OF POSSIBILITIES FOR A FEW SHOWERS ON TUESDAY...BUT FELT THE THREAT WAS SMALL ENOUGH TO GO DRY. TUESDAY NIGHT AND WEDNESDAY SHOULD BE DRY WITH RIDGING IN PLACE AT THE SURFACE. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM EDT MON SEP 1 2014 THE MOST UNSETTLED WEATHER IN THE LONG TERM LOOKS TO OCCUR IN THE FIRST COUPLE OF DAYS...FROM THE BEGINNING OF THE PERIOD WED NIGHT INTO FRI NIGHT. THE LATEST TREND IS FOR A LITTLE MORE POSSIBLE PCPN WED NIGHT INTO THU WITH THE PASSAGE OF THE WARM FRONT THROUGH THE AREA. THIS LOOKS TO BE THE CASE DUE TO THE GRADIENT/LOW LEVEL JET EXPECTED TO BE A LITTLE STRONGER WITH A STRONGER TROUGH MOVING IN. HOW QUICKLY THE FRONT MOVES THROUGH WILL DICTATE HOW WARM WE GET ON THU. IF THE FRONT MOVES QUICK ENOUGH...WE COULD HAVE A CHC TO WARM TOWARD 90 WITH H850 TEMPS OF 20C ADVECTING IN. FOR NOW...WE HAVE SETTLED WITH THE MID-UPPER 80S WITH THE UNCERTAINTY OF THE PCPN. WE WILL SEE ANOTHER BATCH OF CONVECTION BE POSSIBLE THEN CENTERED AROUND FRI AS THE COLD FRONT PUSHES THROUGH AND ENCOUNTERING THE VERY WARM AND MOIST AIR MASS. WE COULD HAVE SOME ASSISTANCE VIA THE RRQ OF AN UPPER JET TO OUR N/NE THAT WOULD SUPPLEMENT THE COLD FRONTAL PASSAGE. THE REMAINDER OF THE LONG TERM FROM SAT THROUGH SUN LOOKS TO BE RATHER QUIET...YET COOL. WE WILL SEE A CANADIAN AIR MASS FILTER IN BEHIND THE THU/FRI SYSTEM WITH A DECENT NNE LOW LEVEL FLOW USHERING IT IN. THE UPPER FLOW WILL BE FROM THE NW AND A BIT OF A TROUGH WILL BE OVER THE AREA. THE FAR ERN FLANK OF A SFC RIDGE WILL BE BUILDING IN AS THE SYNOPTIC PATTERN OVER THE COUNTRY WILL FEATURE A FAIRLY BROAD/EXPANSIVE UPPER RIDGE FROM THE ERN PACIFIC INTO THE ROCKIES. THIS SHOULD KEEP THE AREA DRY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 749 AM EDT MON SEP 1 2014 COMPLICATED WEATHER SCENARIO IN PLACE THIS MORNING WITH STRATUS MOVING NORTH THROUGH THE TAF SITES AND THE POTENTIAL FOR THUNDERSTORMS LOOMING. THE STRATUS AND FOG SHOULD GRADUALLY LIFT THROUGH THE COURSE OF THE MORNING...BUT IT HAS BECOME FAIRLY EXTENSIVE ACROSS SOUTHERN LOWER MICHIGAN. BY AFTERNOON...EXPECTING VFR CEILINGS AND VSBYS OUTSIDE OF THUNDERSTORMS. AS FOR THUNDERSTORMS...THEY ARE ALREADY DEVELOPING ACROSS PORTIONS OF NORTHERN ILLINOIS AND NORTHERN INDIANA. THE TREND SHOULD BE FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE THROUGH THE TAF SITES FROM 14Z OR SO THROUGH 23Z. TOO DIFFICULT TO NAIL DOWN PREVAILING TIMING AT THIS POINT GIVEN THE HIT OR MISS NATURE TO TODAY/S STORMS...SO HAVE VCTS WORDING IN ALL THE TAFS THIS AFTERNOON. OVERNIGHT...EXPECTING THE SHOWERS AND STORMS TO END WITH MVFR CEILINGS TRYING TO SETTLE BACK IN. IT WILL BECOME WINDY TODAY OUT OF THE SOUTH-SOUTHWEST...ESPECIALLY FROM 15Z-23Z. WINDS FROM 200-220 AT 15-25 KNOTS SHOULD BE COMMON. && .MARINE... ISSUED AT 1100 AM EDT MON SEP 1 2014 SCA/BEACH HAZARD WORKING WELL WITHWIND GUSTS NEAR 30 KTS AND WAVE AROUND 4 FT OBSERVED NORTH OF HOLLAND TOWARDS LUDINGTON AT THIS TIME. WINDS WILL CONTINUE NEXT SEVERAL HOURS WITH WAVES UP TO 5 FEET. WINDS / WAVES WILL SUBSIDE QUICKLY LATE THIS AFTERNOON WITH PASSAGE OF FRONT AND SHIFT OF WINDS TO A MORE WESTERLY DIRECTION. THE NEXT POSSIBLE SET OF HEADLINES THAT MAY BE NEEDED FOR THE NEARSHORE WATERS LOOKS TO START IN THE WED NIGHT/THU TIME FRAME AS THE FLOW STRENGTHENS WITH A SURGE OF WARMER AIR WITH THE NEXT FRONTAL SYSTEM POISED TO MOVE IN. && .HYDROLOGY... ISSUED AT 330 AM EDT MON SEP 1 2014 LOCALLY HEAVY RAIN IS CERTAINLY POSSIBLE TODAY GIVEN PRECIPITABLE WATER VALUES SURGING TOWARDS 2 INCHES THIS AFTERNOON. THE RAIN WILL BE CONVECTIVE IN NATURE THOUGH...SO ANY HEAVY RAIN WILL OCCUR IN SWATHS AS OPPOSED TO BEING WIDESPREAD. RIVER LEVELS ARE ALL WITHIN BANK...AND FORECAST BASIN AVERAGE RAINFALL AMOUNTS ARE ON THE ORDER OF 0.20 TO 0.50 INCHES. THESE AMOUNTS SHOULD BE ABLE TO BE ABSORBED BY THE RIVER SYSTEMS WITHOUT MUCH ISSUE. TODAY/S ISSUE THOUGH WILL BE MONITORING THE SWATHS OF HEAVIER RAIN THAT SWEEP THROUGH WITH THE STORMS. THINKING THE MOTION WILL BE QUICK ENOUGH (NORTHEAST AT 35-45 MPH)...TO PREVENT MUCH OF AN ISSUE WITH FLASH FLOODING. NEXT GOOD CHANCE FOR RAIN WILL COME LATER THIS WEEK WITH A WARM FRONT WEDNESDAY NIGHT INTO THURSDAY MORNING AND AGAIN FRIDAY AHEAD OF A COLD FRONT. TOTAL RAINFALL WITH THIS SYSTEM COULD BE ON THE ORDER OF A HALF INCH TO AN INCH. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ037-043-050- 056-064-071. LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849. && $$ SYNOPSIS...DUKE SHORT TERM...COBB LONG TERM...NJJ AVIATION...DUKE HYDROLOGY...DUKE MARINE...COBB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
744 AM EDT MON SEP 1 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT MON SEP 1 2014 WV IMAGERY AND RUC INDICATED A BROAD MID/UPPER LEVEL TROUGH FROM THE ROCKIES INTO THE NRN/CNTRL PLAINS. AT THE SFC...A COLD FRONT EXTENDED FROM NEAR INL THROUGH CNTRL MN INTO NW IA. A WEAK SHRTWV FROM NE MN INTO NW WI SUPPORTED AN AREA OF SHOWERS AND ISOLD TSRA OVER ERN MN INTO NW WI AND LAKE SUPERIOR. A STRONGER SHRTWV WAS LOCATED OVER SW MN INTO NW IA. WITH ONLY MODEST 500-1000 J/KG MUCAPE...ONLY A FEW TSRA WERE NOTED OVER THE REGION. THE MORE ACTIVE CONVECTION OVER ERN LAKE SUPERIOR WAS ASSOCIATED WITH AN AREA OF STRONGER 850 THETA-E ADVECTION AT THE NOSE OF THE LLJ. TODAY...AS THE NW IA SHRTWV LIFTS TOWARD THE AREA WITH MODERATE 700-300 MB QVECTOR CONV AND THE COLD FRONT APPROACHES THE AREA...EXPECT SHRA/TSRA COVERAGE TO INCREASE THIS MORNING. EVEN WITH 0-1KM/0-6KM SHEAR AROUND 40 KNOTS...SINCE INSTABILITY WILL REMAIN LIMITED...MAINLY JUST BRIEF HEAVY RAIN IS EXPECTED. OVERALL RAINFALL AMOUNTS SHOULD BE LIMITED GIVEN THE QUICK MOVEMENT OF THE CONVECTIVE CELLS AND LACK OF LARGE SCALE ORGANIZATION. THE PCPN WILL DIMINISH FROM WEST TO EAST THIS AFTERNOON AS THE COLD FRONT MOVES THROUGH AND QVECTOR DIV SPREADS INTO UPPER MI IN THE WAKE OF THE SHRTWV. CLOUD COVER WILL KEEP HIGH TEMPS NEAR OR SLIGHTLY BELOW SEASONAL AVERAGES IN THE UPPER 60S TO AROUND 70. TONIGHT...ANY LINGERING PCPN OVER THE ERN CWA IN THE EVENING WILL END EARLY. OTHERWISE...A DRIER AIRMASS MOVING INTO THE AREA WITH DEWPOINTS DROPPING TOWARD THE LOWER 50S WILL ALLOW TEMPS TO ALSO DROP INTO THE LOWER TO MID 50S AS SKIES PARTIALLY CLEAR. AN INCREASE IN CLOUD COVER IS EXPECTED LATE OVER THE SW CWA AHEAD OF THE NEXT WEAK SHRTWV. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 321 AM EDT MON SEP 1 2014 IN THE WAKE OF STRONGER SHORTWAVE AND SFC FRONT MOVING THROUGH TODAY...ANOTHER SHORTWAVE CLIPS ACROSS THE AREA ON TUESDAY IN INCREASINGLY ZONAL FLOW ALOFT. MOISTURE IS LIMITED WITH THE WAVE AS SOUNDINGS ONLY SHOW MOISTURE H8-H7. PRETTY HIGH BASED SHRA AND WILL ALSO MENTION ISOLD TSRA WITH MLCAPE 500-1000 J/KG PER ECMWF AND GFS. WILL INCLUDE SLIGHT CHANCE POPS. A LULL FOR TUE NIGHT AS SFC RIDGE MOVES FROM MIDDLE MISSISSIPPI RIVER VALLEY TO THE OHIO VALLEY. LGT SW WINDS ON PERIFERY OF THE RIDGE WILL LIMIT COOLING. LOWEST PWAT FAR EAST CWA WHERE MIN TEMPS MAY FALL TO AROUND 50 DEGREES. ON WEDNESDAY...GFS AND GEM-NH INDICATE SOME SHOWERS COULD OCCUR IN THE AFTN OVER MAINLY THE WEST HALF CWA. WEAK SHORTWAVE IS THERE BUT ONLY APPEARS THAT BEST MOISTURE INFLOW IS OVER FAR WEST CWA. WARM AIR ADVECTION BOOSTS H85 TEMPS TO AROUND +15C SO AS LONG AS SKIES STAY AT LEAST PARTLY CLOUDY...MAX TEMPS WILL TOP OUT IN THE MID 70S TO LOWER 80S. LATER WEDNESDAY NIGHT INTO THURSDAY MORNING LARGER SCALE LIFT AHEAD OF UPPER TROUGH INCREASES OVER NORTHERN PLAINS AND WESTERN GREAT LAKES. LIKELY WILL BE SOME SHORTWAVES SLIDING OUT OF NORTHERN PLAINS AS WELL...THOUGH RIGHT NOW SIGNAL OF ANY STRONGER SHORTWAVE IS MINIMAL. THERE IS A MID LEVEL JET MAX SLIDING OVER THE AREA AND H85-H5 Q-VECTOR CONVERGENCE WILL BE ON THE INCREASE. PRIMARY SFC TROUGH WILL BE OVER MINNESOTA AND BASED ON SFC WINDS AND DWPNTS...THERE WILL BE A WARM FRONT VCNTY OF SOUTHERN/CENTRAL MINNESOTA INTO WESTERN WISCONSIN. BULGE OF WARMTH ALOFT RESULTS IN AN ELEVATED MIXED LAYER WITH H7-H5 LAPSE RATES OVER 8C/KM MAKING IT OVER UPR LAKES AHEAD OF THE SFC TROUGH. RESERVOIR OF ML MUCAPE OVER 2000J/KG WILL BE JUST SOUTHWEST OF UPR MICHIGAN WITH MID LEVEL FLOW SW-NE. EDGE OF SFC BASED CAPE AND ORIENTATION OF H85-H3 THICKNESSES INDICATE THAT STRONGER STORMS MAY BE MORE TO SOUTHWEST OF UPR MICHIGAN LATER WEDNESDAY NIGHT INTO THURSDAY MORNING. TOUGH TO SAY AT THIS POINT THOUGH. CONSENSUS CHANCE POPS WORK FOR NOW SINCE THERE WILL BE LARGE SCALE WARM AIR ADVECTION AND H85-H7 MOISTURE TRANSPORT AIMED INTO THE AREA. MORE SHRA/TSRA POSSIBLE AS SFC FRONT WORKS ACROSS UPR MICHIGAN LATER ON THURSDAY. PLENTY OF INSTABILITY AS TEMPS IN THE SOUTH-SOUTHWEST FLOW AHEAD OF FRONT SHOULD REACH TOWARD 80 DEGREES WITH EVEN A FEW HOURS OF PARTIAL CLEARING SINCE H85 TEMPS ARE 18-20C. MOISTURE AVAILABILITY/MID LEVEL CAPPING ALONG THE FRONT REMAINS A CONCERN FOR COVERAGE OF SFC BASED STORMS IN THE AFTN. MODELS MAY BE PICKING UP ON THIS AS GFS/ECMWF SHOW A MIN IN QPF 18Z-24Z BUT THEN INCREASE IT BY 06Z ON FRIDAY AS FRONT WILL MAINLY BE SOUTH AND EAST OF CWA BY THAT TIME. NO NEED TO GET TOO FANCY WITH THE GRIDS ATTM GIVEN ALL THE UNCERTAINTY. KEPT WITH THE CONSENSUS CHANCE POPS ON THURSDAY WITH THIS DROPPING OFF TO LOWER CHANCES THURSDAY NIGHT CLOSER TO THE DEPARTING FRONT. REST OF THE FORECAST LOOKS DRY AND COOLER AS HIGH PRESSURE BUILDS IN ON FRIDAY AND WILL HOLD ON THROUGH NEXT WEEKEND. MAX TEMPS IN THE MID 60S TO LOWER 70S. CHILLY LOWS POSSIBLE INLAND BOTH FRIDAY NIGHT AND SATURDAY NIGHT DUE TO THE DRY AIRMASS AND LGT WINDS BENEATH THE HIGH PRESSURE. BIAS CORRECTED GUIDANCES SHOWED MINS IN THE LOWER 40S BUT WOULD NOT BE SURPRISED TO SEE READINGS DIPPING INTO THE 30S EITHER OF THOSE NIGHTS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 743 AM EDT MON SEP 1 2014 IWD...ALTHOUGH THERE MAY BE SOME BREAKS IN THE SHRA...MVFR CONDITIONS WL PREDOMINATE EARLY. THE CIGS ARE LIKELY TO FALL INTO THE IFR RANGE BRIEFLY DURING MID MRNG AS THE FRONT PASSES AND THE WIND SHIFTS TO AN UPSLOPE WNW DIRECTION. THE W WIND BEHIND THE FROPA WILL TAP DRIER AIR AND ALLOW FOR CONDITIONS TO IMPROVE TO VFR DURING THE AFTN. CMX...MVFR CONDITIONS WILL PREDOMINATE EARLY WITH PERIODS OF SHOWERS. A WSHFT TO AN UPSLOPE W DIRECTION BEHIND A FROPA AND WITH SOME CONTINUED -SHRA SHOULD RESULT IN A PERIOD OF IFR CONDITIONS DURING THE LATE MRNG/EARLY AFTN BEFORE THE W WIND TAPS DRIER AIR AND RESULTS IN IMPROVEMENT TO VFR BY LATE IN THE DAY. SAW...EXPECT IFR CIGS TO PERSIST THIS MORNING WITH ABUNDANT LOW LEVEL MOISTURE AND UPSLOPE SRLY FLOW. EXPECT SOME SHRA WITH MVFR CONDITIONS TO DEVELOPP BY LATE MORNING WITH THE APPROACH OF A SFC COLD FRONT. EXPECT IMPROVEMENT LATE IN THE AFTERNOON WITH A WSHFT TO A DOWNSLOPE W DIRECTION AND THE ARRIVAL OF DRIER AIR FOLLOWING THE FROPA. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT MON SEP 1 2014 WINDS WILL BE 20 KNOTS OR LESS THROUGH THIS FORECAST PERIOD WITH AREAS OF FOG PERSISTING UNTIL DRIER AIR MOVES INTO THE REGION TONIGHT. && .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 MARQUETTE MI
515 AM EDT MON SEP 1 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT MON SEP 1 2014 WV IMAGERY AND RUC INDICATED A BROAD MID/UPPER LEVEL TROUGH FROM THE ROCKIES INTO THE NRN/CNTRL PLAINS. AT THE SFC...A COLD FRONT EXTENDED FROM NEAR INL THROUGH CNTRL MN INTO NW IA. A WEAK SHRTWV FROM NE MN INTO NW WI SUPPORTED AN AREA OF SHOWERS AND ISOLD TSRA OVER ERN MN INTO NW WI AND LAKE SUPERIOR. A STRONGER SHRTWV WAS LOCATED OVER SW MN INTO NW IA. WITH ONLY MODEST 500-1000 J/KG MUCAPE...ONLY A FEW TSRA WERE NOTED OVER THE REGION. THE MORE ACTIVE CONVECTION OVER ERN LAKE SUPERIOR WAS ASSOCIATED WITH AN AREA OF STRONGER 850 THETA-E ADVECTION AT THE NOSE OF THE LLJ. TODAY...AS THE NW IA SHRTWV LIFTS TOWARD THE AREA WITH MODERATE 700-300 MB QVECTOR CONV AND THE COLD FRONT APPROACHES THE AREA...EXPECT SHRA/TSRA COVERAGE TO INCREASE THIS MORNING. EVEN WITH 0-1KM/0-6KM SHEAR AROUND 40 KNOTS...SINCE INSTABILITY WILL REMAIN LIMITED...MAINLY JUST BRIEF HEAVY RAIN IS EXPECTED. OVERALL RAINFALL AMOUNTS SHOULD BE LIMITED GIVEN THE QUICK MOVEMENT OF THE CONVECTIVE CELLS AND LACK OF LARGE SCALE ORGANIZATION. THE PCPN WILL DIMINISH FROM WEST TO EAST THIS AFTERNOON AS THE COLD FRONT MOVES THROUGH AND QVECTOR DIV SPREADS INTO UPPER MI IN THE WAKE OF THE SHRTWV. CLOUD COVER WILL KEEP HIGH TEMPS NEAR OR SLIGHTLY BELOW SEASONAL AVERAGES IN THE UPPER 60S TO AROUND 70. TONIGHT...ANY LINGERING PCPN OVER THE ERN CWA IN THE EVENING WILL END EARLY. OTHERWISE...A DRIER AIRMASS MOVING INTO THE AREA WITH DEWPOINTS DROPPING TOWARD THE LOWER 50S WILL ALLOW TEMPS TO ALSO DROP INTO THE LOWER TO MID 50S AS SKIES PARTIALLY CLEAR. AN INCREASE IN CLOUD COVER IS EXPECTED LATE OVER THE SW CWA AHEAD OF THE NEXT WEAK SHRTWV. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 321 AM EDT MON SEP 1 2014 IN THE WAKE OF STRONGER SHORTWAVE AND SFC FRONT MOVING THROUGH TODAY...ANOTHER SHORTWAVE CLIPS ACROSS THE AREA ON TUESDAY IN INCREASINGLY ZONAL FLOW ALOFT. MOISTURE IS LIMITED WITH THE WAVE AS SOUNDINGS ONLY SHOW MOISTURE H8-H7. PRETTY HIGH BASED SHRA AND WILL ALSO MENTION ISOLD TSRA WITH MLCAPE 500-1000 J/KG PER ECMWF AND GFS. WILL INCLUDE SLIGHT CHANCE POPS. A LULL FOR TUE NIGHT AS SFC RIDGE MOVES FROM MIDDLE MISSISSIPPI RIVER VALLEY TO THE OHIO VALLEY. LGT SW WINDS ON PERIFERY OF THE RIDGE WILL LIMIT COOLING. LOWEST PWAT FAR EAST CWA WHERE MIN TEMPS MAY FALL TO AROUND 50 DEGREES. ON WEDNESDAY...GFS AND GEM-NH INDICATE SOME SHOWERS COULD OCCUR IN THE AFTN OVER MAINLY THE WEST HALF CWA. WEAK SHORTWAVE IS THERE BUT ONLY APPEARS THAT BEST MOISTURE INFLOW IS OVER FAR WEST CWA. WARM AIR ADVECTION BOOSTS H85 TEMPS TO AROUND +15C SO AS LONG AS SKIES STAY AT LEAST PARTLY CLOUDY...MAX TEMPS WILL TOP OUT IN THE MID 70S TO LOWER 80S. LATER WEDNESDAY NIGHT INTO THURSDAY MORNING LARGER SCALE LIFT AHEAD OF UPPER TROUGH INCREASES OVER NORTHERN PLAINS AND WESTERN GREAT LAKES. LIKELY WILL BE SOME SHORTWAVES SLIDING OUT OF NORTHERN PLAINS AS WELL...THOUGH RIGHT NOW SIGNAL OF ANY STRONGER SHORTWAVE IS MINIMAL. THERE IS A MID LEVEL JET MAX SLIDING OVER THE AREA AND H85-H5 Q-VECTOR CONVERGENCE WILL BE ON THE INCREASE. PRIMARY SFC TROUGH WILL BE OVER MINNESOTA AND BASED ON SFC WINDS AND DWPNTS...THERE WILL BE A WARM FRONT VCNTY OF SOUTHERN/CENTRAL MINNESOTA INTO WESTERN WISCONSIN. BULGE OF WARMTH ALOFT RESULTS IN AN ELEVATED MIXED LAYER WITH H7-H5 LAPSE RATES OVER 8C/KM MAKING IT OVER UPR LAKES AHEAD OF THE SFC TROUGH. RESERVOIR OF ML MUCAPE OVER 2000J/KG WILL BE JUST SOUTHWEST OF UPR MICHIGAN WITH MID LEVEL FLOW SW-NE. EDGE OF SFC BASED CAPE AND ORIENTATION OF H85-H3 THICKNESSES INDICATE THAT STRONGER STORMS MAY BE MORE TO SOUTHWEST OF UPR MICHIGAN LATER WEDNESDAY NIGHT INTO THURSDAY MORNING. TOUGH TO SAY AT THIS POINT THOUGH. CONSENSUS CHANCE POPS WORK FOR NOW SINCE THERE WILL BE LARGE SCALE WARM AIR ADVECTION AND H85-H7 MOISTURE TRANSPORT AIMED INTO THE AREA. MORE SHRA/TSRA POSSIBLE AS SFC FRONT WORKS ACROSS UPR MICHIGAN LATER ON THURSDAY. PLENTY OF INSTABILITY AS TEMPS IN THE SOUTH-SOUTHWEST FLOW AHEAD OF FRONT SHOULD REACH TOWARD 80 DEGREES WITH EVEN A FEW HOURS OF PARTIAL CLEARING SINCE H85 TEMPS ARE 18-20C. MOISTURE AVAILABILITY/MID LEVEL CAPPING ALONG THE FRONT REMAINS A CONCERN FOR COVERAGE OF SFC BASED STORMS IN THE AFTN. MODELS MAY BE PICKING UP ON THIS AS GFS/ECMWF SHOW A MIN IN QPF 18Z-24Z BUT THEN INCREASE IT BY 06Z ON FRIDAY AS FRONT WILL MAINLY BE SOUTH AND EAST OF CWA BY THAT TIME. NO NEED TO GET TOO FANCY WITH THE GRIDS ATTM GIVEN ALL THE UNCERTAINTY. KEPT WITH THE CONSENSUS CHANCE POPS ON THURSDAY WITH THIS DROPPING OFF TO LOWER CHANCES THURSDAY NIGHT CLOSER TO THE DEPARTING FRONT. REST OF THE FORECAST LOOKS DRY AND COOLER AS HIGH PRESSURE BUILDS IN ON FRIDAY AND WILL HOLD ON THROUGH NEXT WEEKEND. MAX TEMPS IN THE MID 60S TO LOWER 70S. CHILLY LOWS POSSIBLE INLAND BOTH FRIDAY NIGHT AND SATURDAY NIGHT DUE TO THE DRY AIRMASS AND LGT WINDS BENEATH THE HIGH PRESSURE. BIAS CORRECTED GUIDANCES SHOWED MINS IN THE LOWER 40S BUT WOULD NOT BE SURPRISED TO SEE READINGS DIPPING INTO THE 30S EITHER OF THOSE NIGHTS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 132 AM EDT MON SEP 1 2014 IWD...LLWS AND NMRS HEAVY SHRA WITH SOME EMBEDDED TS RIDING NNEWD UNDER A STRONG SSW LLJ IN ADVANCE OF A SLOW MOVING COLD FNT WILL IMPACT THIS SITE THRU SUNRISE. ALTHOUGH THERE MAY BE SOME BREAKS IN THE HEAVIER SHRA...MVFR CONDITIONS WL PREDOMINATE. THE CIGS ARE LIKELY TO FALL INTO THE IFR RANGE BRIEFLY DURING MID MRNG AS THE FNT PASSES AND THE WIND SHIFTS TO AN UPSLOPE WNW DIRECTION. THE W WIND BEHIND THE FROPA WL TAP DRIER AIR AND ALLOW FOR CONDITIONS TO IMPROVE TO VFR DURING THE AFTN. CMX...VFR CONDITIONS WL DOMINATE EARLY IN THE TAF PERIOD BUT THEN GIVE WAY TO MVFR WX AS A BAND OF MDT-HVY SHRA AHEAD OF THE SLOWLY APRCHG COLD FNT EDGES SLOWLY TO THE E. LLWS WL BE THE RULE THRU SUNRISE UNDER A STRONG SW LLJ. A WSHFT TO AN UPSLOPE W DIRECTION BEHIND THE FROPA AND WITH SOME CONTINUED -SHRA WL RESULT IN A PERIOD OF IFR CONDITIONS DURING THE LATE MRNG/EARLY AFTN BEFORE THE W WIND TAPS DRIER AIR AND RESULTS IN IMPROVEMENT TO VFR BY LATE IN THE DAY. SAW...EXPECT LO CLDS/IFR CIGS TO LINGER THRU THE NGT WITH A MOIST SLY FLOW UNDER A STRONG SW LLJ SUFFICIENT TO CAUSE LLWS DRAWING LLVL MSTR N FM LK MI IN THE PRESENCE OF DIURNAL COOLING. EXPECT SOME SHRA WITH MVFR CONDITIONS TO DVLP BY LATE MRNG WITH THE CLOSER APRCH OF SFC COLD FNT. EXPECT IMPROVEMENT LATE IN THE AFTN WITH A WSHFT TO A DOWNSLOPE W DIRECTION AND ARRIVAL OF DRIER AIR FOLLOWING THE FROPA. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT MON SEP 1 2014 WINDS WILL BE 20 KNOTS OR LESS THROUGH THIS FORECAST PERIOD WITH AREAS OF FOG PERSISTING UNTIL DRIER AIR MOVES INTO THE REGION TONIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
149 AM EDT MON SEP 1 2014 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 322 PM EDT SUN AUG 31 2014 A WEAK AREA OF HIGH PRESSURE WILL KEEP MUCH OF THE REGION DRY INTO THE EVENING. A COLD FRONT WILL APPROACH FROM THE WEST ON LABOR DAY TRIGGERING SHOWERS AND THUNDERSTORMS. HIGH PRESSURE WILL RETURN FOR TUESDAY DRYING THE REGION OUT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 322 PM EDT SUN AUG 31 2014 THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE POTENTIAL FOR SEVERE WEATHER ON MONDAY. OVERALL THE POTENTIAL STILL EXISTS. ONE POTENTIAL LIMITING FACTOR WILL BE WHAT IMPACTS THE DECAYING AREA OF THUNDERSTORMS WILL HAVE AS IT MOVES IN FROM THE WEST MONDAY MORNING. THE HRRR RUC SHOWS THIS SYSTEM WEAKENING WELL BEFORE IT ARRIVES IN MI...SO I AM THINKING THIS WILL HAVE A MINIMAL IMPACT ON THE POTENTIAL INSTABILITY MONDAY. THE COMBINATION OF HEATING AND MOISTURE ADVECTION SUPPORTS CAPE OVER 1500 J/KG ON MONDAY. DEEP LAYER SHEAR INCREASES TOWARD 18Z AS THE MID LEVEL WAVE CURRENTLY IN WI ARRIVES IN NW LOWER. THE LIFT ASSOCIATED WITH THIS FEATURE SHOULD TRIGGER STORMS. THE SHEAR WILL HELP TO INCREASE THE POTENTIAL FOR ORGANIZED CONVECTION AND RESULTING SEVERE WEATHER. DAMAGING WINDS AND LARGE HAIL A THREAT. SRH VALUES AROUND 200 M2/S2 DO SUPPORT A RISK FOR TORNADOES. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 322 PM EDT SUN AUG 31 2014 MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT INTO NEXT WEEKEND... HOWEVER THERE ARE TIMING DIFFERENCES WITH A STRONG COLD FRONT THAT COMES THROUGH FRIDAY/FRIDAY NIGHT. LARGE HIGH PRESSURE IS EXPECTED TO BE SITTING OVER THE EAST SEABOARD BY MID WEEK. THIS WILL BRING WARMING SOUTHERLY FLOW TO THE GREAT LAKES REGION. IT CONTINUES TO LOOK LIKE THURSDAY WILL BE THE WARMEST DAY OF THE WEEK WITH 80S FOR HIGHS. THE RISK FOR SHOWERS AND STORMS WILL INCREASE ON THURSDAY WITH A COLD FRONT MOVING INTO THE WESTERN GREAT LAKES. WARM AND MOIST AIR WITH MOVE IN AHEAD OF THIS FRONT. IF A LOW LEVEL JET COMES INTO PLAY WE COULD BE LOOKING AT STRONG TO SEVERE STORMS TOWARD THE END OF THE DAY. THERE CONTINUES TO BE TIMING DIFFERENCES WITH THE FRONT...BUT THE GFS SLOWED THE FRONT DOWN...CLOSER TO THE WHAT THE ECMWF HAS SHOWN. THEREFORE BELIEVE THE FRONT WILL BE COMING THROUGH ON FRIDAY WITH ADDITIONAL CHANCES FOR SHOWERS AND STORMS. MUCH COOLER AIR FOLLOWS THIS STRONG FRONT FOR FRIDAY NIGHT AND INTO NEXT WEEKEND. H8 TEMPS DROP TO +7 TO +10C AS COMPARED TO AROUND +19C AHEAD OF THE COLD FRONT. THE WEEKEND SHOULD FEATURE HIGHS IN THE UPPER 60S TO MID 70S WITH MAINLY DRY WEATHER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 149 AM EDT MON SEP 1 2014 THERE ARE A FEW ITEMS THAT COULD IMPACT AVIATION OPERATIONS OVER THE NEXT 24 HOURS ACROSS SW LOWER MI. THE FIRST ITEM IS FOG POTENTIAL. A DECENT AMOUNT OF LOW LEVEL MOISTURE REMAINS IN PLACE THIS MORNING AND TEMPS AND DEW POINTS ARE CLOSE ALREADY. THE BEST CHC FOR FOG AND SOME POSSIBLE STRATUS WILL BE ALONG AND SE OF I-69 WHERE A FEW SHOWERS WERE PRESENT EARLIER AND WHERE THE MOISTURE HAS HUNG IN THE MOST. CAN NOT RULE OUT SOME NEAR KGRR AND KAZO...BUT THE FURTHER WEST THE WINDS WILL REMAIN UP AND LIMIT FOG POTENTIAL. THE NEXT THING IS THE POTENTIAL FOR PCPN TODAY. MOST DATA INDICATES THAT WHATEVER IS LEFT OF THE LINE OF SHOWERS/STORMS NEAR THE MISSISSIPPI RIVER AS OF 0545Z WILL MOVE INTO THE AREA TOWARD 15Z OR SO. IT WILL INITIALLY FALL APART WITH LESS CHC OF IMPACTS FROM IT TOWARD THE LAKESHORE. AS IT ENCOUNTERS SOME DIURNAL INSTABILITY TOWARD THE EAST...WE EXPECT IT TO REINTENSIFY INTO A LINE OF STORMS BY THE TIME IT REACHES U.S.-127 BY 19Z OR SO. BEST CHC FOR LOWER CONDITIONS WILL BE ACROSS THE EAST WHERE IFR WOULD BE LIKELY IN HEAVY RAINFALL. THIS CAN BE FINE TUNED CLOSER TO THE EVENT. ONCE THE LINE OF STORMS MOVES EAST...THERE SHOULD BE SOMEWHAT OF A BREAK. ANOTHER PERIOD OF SOME SHOWERS WILL BE POSSIBLE WITH THE WAVE TOWARD 00Z AND AFTER THAT. && .MARINE... ISSUED AT 322 PM EDT SUN AUG 31 2014 BEACH HAZARDS AND SCA ISSUED FOR MONDAY && .HYDROLOGY... ISSUED AT 322 PM EDT SUN AUG 31 2014 HIGH PWAT VALUES SUPPORT LOCALLY HEAVY RAIN ON MONDAY. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...BEACH HAZARDS STATEMENT FROM 10 AM EDT THIS MORNING THROUGH THIS EVENING FOR MIZ037-043-050-056-064-071. LM...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 10 PM EDT THIS EVENING FOR LMZ844>849. && $$ SYNOPSIS...MJS SHORT TERM...MJS LONG TERM...JK AVIATION...NJJ HYDROLOGY...MJS MARINE...MJS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
447 AM CDT MON SEP 1 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT MON SEP 1 2014 A FAIRLY BROAD LONGWAVE TROUGH WAS SETTING UP THIS MORNING FROM THE GREAT LAKES BACK TO THE PAC NW. THE MAIN PIECE OF ENERGY EMBEDDED WITHIN THIS TROUGH IS THE TROUGH WORKING INTO WRN IA/SRN MN THIS MORNING. THERE IS A FAIRLY POTENT SHORTWAVE WITHIN THIS TROUGH NEAR SIOUX FALLS...AS EVIDENCE BY THE NICE SPIN SEEN WITHIN THE KFSD REFLECTIVITY. AT THE SFC...A BROAD FRONTAL TROUGH WAS SITUATED ACROSS MN...THOUGH THE WIND SHIFT AND T/TD DROP YOU COULD ASSOCIATE WITH THE MAIN FRONT WAS SITUATED FROM ABOUT CANBY UP TO INTERNATIONAL FALLS. 8Z SPC MESO ANALYSIS STILL SHOWED ABOUT 500 J/KG OF SBCAPE OUT AHEAD OF THIS BOUNDARY. THIS INSTABILITY COMBINED WITH LIFT FROM THE WAVE NEAR SIOUX FALLS EXPLAINS WHY WE HAVE CONTINUED TO SEE NEW CONVECTION DEVELOP THROUGH THE NIGHT OUT IN WRN MN. ALTHOUGH NONE OF THE CAMS HAVE HANDLED THIS TRAILING ACTIVITY WELL...THE LOCAL WRF HAS HANDLED IT THE BEST THIS MORNING...SO FOLLOWED IT FOR SLOWLY DRAGGING POPS ACROSS THE AREA THIS MORNING. LOOKS LIKE IT WILL TAKE UNTIL BETWEEN 15 AND 18Z TO COMPLETELY CLEAR THIS ACTIVITY OUT OF WRN WI. DUE TO LIMITED INSTABILITY...THE SEVERE POTENTIAL WITH THIS ACTIVITY WILL ESSENTIALLY BE NIL...BUT WE WILL CONTINUE TO SEE HEAVY DOWNPOURS...WITH A QUICK HALF TO ONE INCH OF RAIN LIKELY FOR AREAS THAT GET UNDER HEAVIER RAIN CORES. BEHIND THIS SYSTEM SKIES WILL CLEAR OUT FOR A BIT...BUT BY THE AFTERNOON...TROUGH AXIS CURRENTLY SITUATED FROM SASKATCHEWAN DOWN INTO ERN IDAHO WILL BE SPREADING MID CLOUDS INTO WRN MN AS IT QUICKLY TRACKS ACROSS THE DAKOTAS WITHIN A MODERATELY FAST ZONAL FLOW. WILL LIKELY SEE SOME SCATTERED DIURNALLY DRIVEN ACTIVITY DEVELOP ACROSS THE DAKOTAS AHEAD OF THE WAVE THAT WILL MAKE A RUN FOR WRN MN EARLY THIS EVENING BEFORE WE LOSE DAYTIME HEATING. AS A RESULT...REMOVED POPS AFTER 3Z. THALER QG DIAGNOSTICS SHOWS SUBSIDENCE DOMINATING MN/WI TONIGHT AND WITH THE LOSS OF DIURNAL HEATING...ALL CAMS SHOW ACTIVITY DISSIPATING. ALTHOUGH THE NAM/GFS CONTINUE TO SHOW SOME LIGHT QPF ACROSS MN THROUGH THE NIGHT...DECIDED TO SIDE MORE TOWARD THE FORCING THAN MODEL GENERATED QPF IN GOING WITH THE DRY FORECAST AFTER 3Z. FOR HIGHS TODAY...DO EXPECT A DESCENT AMOUNT OF SUNSHINE FOR THE LATE MORNING THROUGH MUCH OF THE AFTERNOON...WITH H85 TEMPS EXPECTED TO BE A COUPLE OF DEGREES ON EITHER SIDE OF 16C. BUFKIT SOUNDINGS SHOW US MIXING UP TO ABOUT 825 AND MIXING THOSE TEMPERATURES DOWN TO THE SFC ON THE NAM SPIT BACK OUT HIGHS IN THE MID/UPPER 70S...SO DID NUDGE HIGHS UP A FEW DEGREES...WHICH SIMPLY PUT US TOWARD THE HIGHER END OF THE GUIDANCE ENVELOP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 340 AM CDT MON SEP 1 2014 SIGNS OF EARLY FALL ARE IN THE AIR WITH A PERSISTENT WEST COAST TROUGH AND WESTERLY FLOW ACROSS THE UPPER MISSISSIPPI THROUGH THE EXTENDED. THERE ARE ALSO A STRONG COLD FRONTS EXPECTED OVER THE NEXT 7-10 DAYS PRECEDED BY BRIEF BOUTS OF WARMTH AND INCREASED HUMIDITY. TUESDAY SHOULD FEATURE QUIET AND PLEASANT WEATHER WITH MID-LEVEL HEIGHT RISES...AND SURFACE RIDGING JUST SOUTH OF THE FORECAST AREA. WARM AIR ADVECTION SHOULD BEGIN IN EARNEST BY TUESDAY AFTERNOON AS WARMER AIR FROM THE PLAINS REPLACES THE COOLER AIR MASS TIED TO MONDAY`S TROUGH. WEDNESDAY LOOKS LIKE THE MOST INTERESTING DAY OF THE UPCOMING WEEK IN TERMS OF THUNDER POTENTIAL AND EVEN SMALL PROBABILITIES FOR SEVERE WEATHER IN MN. A FAST MOVING UPPER WAVE WILL MOVE FROM THE PACIFIC NORTHWEST TO NEARLY HUDSON BAY IN APPROXIMATELY 48 HOURS. A SURFACE LOW IS EXPECTED TO DEVELOP IN THE DAKOTAS AND MOVE INTO NW MN BY 12Z THURSDAY. THE LOCATION OF THE ASSOCIATED WARM FRONT SHOULD FOCUS A MAJORITY OF THE CONVECTION ACROSS THE NORTHERN HALF OF MN...WITH THE 01.00Z GFS/NAM/ECMWF KEEPING QPF BULLS EYE NORTH OF I-94. THERE IS THE POTENTIAL FOR STRONG TO SEVERE STORMS NEAR THE WARM FRONT. BOTH THE GFS/NAM GENERATE 2000-2500J/KG OF MUCAPE BY 21-00Z WEDNESDAY. THERE IS ALSO DECENT FLOW ALOFT WITH 30-40KTS OF DEEP LAYER SHEER AND A VEERING HODOGRAPH. SOUTH OF THE MOST ROBUST CONVECTION...IT SHOULD BE WARM AND STEAMY. WARMEST PLUME OF 850MB ARRIVES THURSDAY MORNING...SETTING UP ANOTHER POTENTIALLY WARM AND HUMID DAY IN THE EASTERN FORECAST AREA ON THURSDAY. BOTH WEDNESDAY AND THURSDAY COULD FEATURE A LOT OF HEAT INDICES IN THE UPPER 80S AND LOWER 90S. A STRONG COLD FRONT PASSES THROUGH BY FRIDAY AND WILL RESULT IN A DRY AND COOLER WEEKEND UNDER HIGH PRESSURE. SO IT LOOKS A FAIRLY QUIET EXTENDED UNTIL PERHAPS THE MIDDLE OF NEXT WEEK WHEN ANOTHER BRIEF WARM-UP AND SHARP COLD FRONT ARE SHOWING UP OFF THE GFS AND ECMWF. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1219 AM CDT MON SEP 1 2014 THUNDER THREAT LARGELY DONE ACROSS THE MPX AIRSPACE...BUT STRONG UPPER WAVE BACK BY SIOUX FALLS STILL HAS TO WORK ACROSS SRN MN/WRN WI TONIGHT...WHICH WILL KEEP SCT SHOWERS GOING THROUGH MUCH OF THE NIGHT...AS WE ARE SEEING WITH THE HRRR. BIGGER QUESTION MARK REVOLVES AROUND STRATUS/FOG POTENTIAL TONIGHT. CERTAINLY THIS STRATIFORM RAIN WE ARE SEE OUT THERE NOW WILL HELP MOISTEN THE ATMO AND INCREASE THE THREAT FOR STRATUS...BUT CIGS AT THE START ARE LARGELY UP AROUND 10K FT...SO WE HAVE A WAYS TO GO. FOLLOWED THE IDEA OF THE RAP THOUGH WITH STATUS EVENTUALLY FILLING IN WITHIN AND EAST OF THE WEAKENING SFC TROUGH...WHICH AT 6Z STRETCHED FROM ABOUT NEW ULM TO MILLE LACS LAKE. THIS MOISTURE LOOKS TO GET SCOURED OUT PRETTY QUICK BY WNW WINDS IN THE MORNING...WITH MOST OF LABOR DAY GOING BY WITH VFR CONDS. DURING THE LATE AFTERNOON...ANOTHER UPPER WAVE WILL BE COMING OUT OF THE DAKOTAS...BUT IT LOOKS TO DO NOTHING MORE THAN PROVIDE US WITH AN INCREASE IN MID CLOUDS AND PERHAPS A FEW SPRINKLES AS WE HEAD INTO MONDAY NIGHT. KMSP...STRATIFORM RAIN WE ARE SEEING NOW FAVORED ME TOWARD KEEPING THE DEVELOPMENT OF SUB 018 CIGS WE HAD IN THE TAF...BUT WITH CIGS STILL ABOVE 5K FT...NOT COMPLETELY SOLD ON THOSE RESTRICTIONS HAPPENING. OTHER THAN THAT...NO OTHER CONCERNS ARE EXPECTED THIS PERIOD. /OUTLOOK FOR KMSP/ TUE...VFR. WINDS WSW 5-10 KTS. WED...VFR. CHC MVFR/TSRA LATE. WINDS S 5-10 KTS. THU...VFR. CHC MVFR/TSRA. WINDS S BCMG W 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...CLF AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1233 AM CDT MON SEP 1 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 252 PM CDT SUN AUG 31 2014 SVR WX PARAMETERS REMAIN FAVORABLE FOR LARGE HAIL/DAMAGING WINDS THIS AFTN/EARLY EVENING. THE MAIN PROBLEM IS AFTN CAP /BASED ON 18Z KMPX SOUNDING/ WHICH HAS SUPPRESSED MOST OF THE CONVECTION ACROSS SOUTHERN MN EARLY THIS AFTN. IN ADDITION...THE MAIN SHRTWV AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE JET CORE MOVING ACROSS COLORADO...IS NOT EXPECTED TO MOVE ACROSS NE/IA/MN UNTIL LATER THIS EVENING. A STRONGER STORM NORTH OF KOMA AS OF 19Z IS A REFLECTION OF A STRENGTHENING LLJ AHEAD OF THIS JET ENERGY MOVING OUT OF COLORADO. SHORT TERM MESOSCALE CONVECTIVE PARAMETERS /HRRR/RUC/ HAVE DEPICTED THAT THE SHRA/TSRA ACROSS SOUTHERN MN SHOULD BE MOVING ACROSS EASTERN MN/WESTERN WI BY 00Z...WITH MOST OF THE STRONGER/SVR ACTIVITY FORMING SOUTH ACROSS IOWA. IN ADDITION...THESE SAME MESOSCALE CONVECTIVE PARAMETERS HAVE ANOTHER LINE OF SHRA/TSRA FORMING WEST OF THE TWIN CITIES ARND 2-4Z ALONG AND AHEAD OF THE APPROACHING SFC FRONT. THIS MAY BE THE MAIN PLAYER TONIGHT...AS SAID BEFORE...THE AFTN CAP WILL LIKELY HOLD FOR A FEW MORE HRS...SETTING THE STAGE FOR AN EVENING EVENT. OTHERWISE...SHRA/TSRA SHOULD CONTINUE TO FORM ALONG AND AHEAD OF THIS SFC FRONT LATER THIS EVENING AND MOVE EASTWARD DURING THE OVERNIGHT HRS. BY MORNING...MOST OF THE ACTIVITY SHOULD BE EAST OF MPX FA...WITH ONLY RESIDUAL SHRA IN WC WI. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 252 PM CDT SUN AUG 31 2014 TUESDAY-WEDNESDAY...THE FIRST COUPLE DAYS OF THE EXTENDED PORTION WILL BE DOMINATED BY GENERALLY ZONAL FLOW ALOFT WHILE SFC HIGH PRES OVER THE CENTRAL PLAINS SHIFTS E INTO THE OHIO VALLEY. THIS WILL SPELL A WEAK PRES PATTERN OVER THE UPR MISS RIVER VALLEY REGION WITH WEAK SUPPORT ALOFT. HOWEVER...THE RELATIVELY WEAK INFLUENCE OF HIGH PRESSURE AS IT STAYS S OF THE REGION MEANS THAT THERE WILL BE FAIRLY INEFFECTIVE CAPPING WITHIN A CONTINUED DEEPLY MOIST ENVIRONMENT. WEAK BUCKLES IN THE ZONAL FLOW CAN EASILY SPARK ISOLD SHOWERS AND POSSIBLY EVEN A HANDFUL OF TSTMS ACRS THE REGION DURING THIS PERIOD SO SPOTTY SLGT CHC POPS ARE MAINTAINED IN THE FCST. MUCH OF THE FCST AREA WILL REMAIN DRY...BUT ANY LOCATIONS THAT DO SEE SOME PRECIP WILL NOT RECEIVE MUCH IN THE WAY OF QPF. OTHERWISE...TEMPS AND DEWPOINTS WILL GO ON A SLIGHT INCREASING TREND AS WINDS SHIFT FROM WLY TO SLY ON THE BACKSIDE OF THE DEPARTING HIGH PRES AREA. WEDNESDAY NIGHT-THURSDAY NIGHT...A LARGE LONGWAVE TROUGH DROPPING OUT OF THE GULF OF ALASKA MON WILL MOVE ONSHORE THE PAC NW REGION TUE EVE AND SLOWLY MAKE ITS WAY INTO THE CENTRAL CONUS DURING THE MIDDLE PORTION OF THE WEEK. THIS TROUGH WILL PICK UP A DEVELOPING LOW PRES CENTER OVER MT...SHIFTING IT INTO THE DAKOTAS AND EVENTUALLY NRN MN BY MIDDAY THU. THE COMBINATION OF THE DIGGING TROUGH AND THIS LOW PRES CENTER DEEPENING OVER THE ERN DAKOTAS AND MN WILL CREATE ADDITIONAL POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS FOR MUCH OF THE AREA LATE WED THRU THU NIGHT. THE FRONT LOOKS TO STALL OUT OVER CENTRAL MN THU...SO THIS MAY ALTER THE DURATION OF HAVING POPS IN THE FCST OVER THE NEXT FEW DAYS WORTH OF MODEL RUNS. FRIDAY-SUNDAY...THOUGH THE SFC REFLECTION OF THE LOW PRES SYSTEM LOOKS TO BE E OF THE WFO MPX CWFA BY DAYBREAK FRI MRNG...THE ASSOCIATED TROUGH AXIS ALOFT WILL BE DRAGGING ITS WAY THROUGH THE REGION DURG THE DAY ON FRI. THIS MAY LEAD TO SOME SHOWERS WITH THE RELATIVE CORE OF THE SYSTEM STILL PASSING THRU. BEHIND THESE DISTURBANCES AT THE SFC AND ALOFT...MORE PRONOUNCED NW FLOW ALOFT WILL DOMINATE THRU THE WEEKEND WHILE HIGH PRES SLOWLY SHIFTS SE. THIS COMBINATION WILL ALLOW FOR A DRYING OUT PERIOD FOR NEXT WEEKEND ALONG WITH COOLER AND LESS HUMID CONDITIONS. HIGHS WILL DROP BACK TO THE UPR 60S AND LWR 70S BY NEXT WEEKEND WITH LOWS FALLING INTO THE UPR 40S AND LWR 50S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1219 AM CDT MON SEP 1 2014 THUNDER THREAT LARGELY DONE ACROSS THE MPX AIRSPACE...BUT STRONG UPPER WAVE BACK BY SIOUX FALLS STILL HAS TO WORK ACROSS SRN MN/WRN WI TONIGHT...WHICH WILL KEEP SCT SHOWERS GOING THROUGH MUCH OF THE NIGHT...AS WE ARE SEEING WITH THE HRRR. BIGGER QUESTION MARK REVOLVES AROUND STRATUS/FOG POTENTIAL TONIGHT. CERTAINLY THIS STRATIFORM RAIN WE ARE SEE OUT THERE NOW WILL HELP MOISTEN THE ATMO AND INCREASE THE THREAT FOR STRATUS...BUT CIGS AT THE START ARE LARGELY UP AROUND 10K FT...SO WE HAVE A WAYS TO GO. FOLLOWED THE IDEA OF THE RAP THOUGH WITH STATUS EVENTUALLY FILLING IN WITHIN AND EAST OF THE WEAKENING SFC TROUGH...WHICH AT 6Z STRETCHED FROM ABOUT NEW ULM TO MILLE LACS LAKE. THIS MOISTURE LOOKS TO GET SCOURED OUT PRETTY QUICK BY WNW WINDS IN THE MORNING...WITH MOST OF LABOR DAY GOING BY WITH VFR CONDS. DURING THE LATE AFTERNOON...ANOTHER UPPER WAVE WILL BE COMING OUT OF THE DAKOTAS...BUT IT LOOKS TO DO NOTHING MORE THAN PROVIDE US WITH AN INCREASE IN MID CLOUDS AND PERHAPS A FEW SPRINKLES AS WE HEAD INTO MONDAY NIGHT. KMSP...STRATIFORM RAIN WE ARE SEEING NOW FAVORED ME TOWARD KEEPING THE DEVELOPMENT OF SUB 018 CIGS WE HAD IN THE TAF...BUT WITH CIGS STILL ABOVE 5K FT...NOT COMPLETELY SOLD ON THOSE RESTRICTIONS HAPPENING. OTHER THAN THAT...NO OTHER CONCERNS ARE EXPECTED THIS PERIOD. /OUTLOOK FOR KMSP/ TUE...VFR. WINDS WSW 5-10 KTS. WED...VFR. CHC MVFR/TSRA LATE. WINDS S 5-10 KTS. THU...VFR. CHC MVFR/TSRA. WINDS S BCMG W 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JLT LONG TERM...JPC AVIATION...MPG
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1151 PM CDT Sun Aug 31 2014 .SHORT TERM...(This Evening through Wednesday Afternoon) Issued at 357 PM CDT SUN AUG 31 2014 Afternoon water vapor imagery showing long advertised Pacific trough digging into the central Plains this afternoon...with strong shortwave energy now seen entering western Nebraska. Strengthening wind fields along the southern edge of this feature have advected Mexican Plateau air /i.e. elevated mixed layer/ east across the central/southern Plains as seen on the latest 7.4 micron water vapor GOES sounder channel. Latest RUC analysis shows 7-500 mb lapse rates approaching 9C/km across western Kansas and Nebraska...and fcst models suggest this mid-level airmass will continue tracking east into our region overnight. Along the surface...latest analysis shows a developing leeside low across southeastern Colorado...with a northward extending frontal boundary draped across the Plains which then joins the main area of low pressure now found along the Minnesota/Manitoba border. With time this evening...aforementioned boundary will progress eastward as upstream troughing continues to settle into the central and southern Plains. Airmass ahead of both the cold front and upper wave continues to destabilize with latest SPC meso graphics yielding as much as 3500 joules of MLCAPE between KC and Topeka. Most importantly however...deep layered shear will continue increasing as well as mid- level wind max moves into the area overnight. All said...ingredients appear to be coming together for a fairly active evening and overnight period. Latest radar trends now showing developing cells across north-central Kansas along the previously mentioned frontal boundary. Storms should continue to fire this afternoon before gradually spreading east through the early evening and overnight. As has been advertised in recent days quite well by numerical models...isolated convection to our west and north will likely congeal into a forward propagating MCS this evening just before it enters northwestern Missouri. As this occurs...deep layered shear will continue to strengthen as a low- level jet increases to nearly 50 kts directly overhead. This poses two potential issues for our region: 1) Maintenance of ongoing severe weather as cold pool continues to track southeast with time into northwest Missouri/northeast Kansas 2) Increasing likelihood for developing heavy rain/possible flooding as low-level jet ascends any convectively generated cold pools The above said...main concerns severe-wise for our area will remain strong damaging winds as cold pool for developing MCS tracks south and east with time. Current thinking is damaging wind potential will gradually decrease as storms approach the greater KC area...however cannot rule out strong gusts in and around the metro during the late evening hrs. Additionally...a low-end tornado threat does exist across far northwest Missouri as strong updrafts continue to tilt horizontal vorticity into the vertical along the leading edge of the cold pool as it tracks south and east with time. For now...agree completely with where SPC has the highest tornado threat /NW MO/ as further progress to the south and east will likely result in a less favorable environment due to nocturnal cooling/low-level stabilization effects. In terms of hydro concerns...have elected to go with a flash flood watch for much of northwest MO/northeast Kansas as potential exists for training convection if an outflow boundary lays out across central Missouri. As alluded to above...strength of developing low- level jet is a little concerning especially when PWAT values are expected to increase to anywhere between 2-3 standard deviations above normal as main front approaches. HPC QPF shows a 2+ inch bullseye directly west of KC which appears to be in favor of developing training after midnight. Would rather play it safe hence the current flash flood watch which runs from 2z this evening through 15z Monday morning. Front to slowly settle south of the region during the early morning hrs. Another round of strong to severe storms is possible on Monday...primarly south of the the greater KC area as daytime heating combines with still impressive wind fields aloft. For tomorrow...more optimal timing may support isolated supercell structures as opposed to tonight/s linear activity. Regardless...have maintained likely pops for most areas south of I-70 during the afternoon hrs. Front to clear the area tomorrow night which should support a mostly dry Tuesday. Front slowly expected to lift north as a warm front through the day on Wednesday but minimal impacts expected as no significant features are at play to enhance upward vertical motion. Temps by then should begin to rise with low to mid 90s possible Wednesday afternoon as southerly flow reinvades the area. .LONG TERM...(Wednesday Evening through Sunday) Issued at 357 PM CDT SUN AUG 31 2014 A little bit of everything during the extended portion of the forecast. Storms early Wednesday, followed by a return of hot and humid air until a cold front and more storms on Friday, then finally some fall-like weather over the weekend. Medium range models all on the same page with the overall pattern. Mid-week zonal flow backs to the southwest in response to an upper trough tracking east from the Northern Rockies through the Upper MS Valley by Friday. Elevated convection associated with a northward returning warm front will affect the CWA early Wednesday followed by hot and humid air spreading back into the region. This will likely last into Friday when the southern extension of the Northern Plains upper trough forces a cold front south and through the Mid MO River Valley by Saturday morning. Moderately strong and broad area of high pressure expanding southward will bring some much needed relief from the high humidities. && .AVIATION...(For the 06Z TAFS through 06Z Monday Night) Issued at 1151 PM CDT SUN AUG 31 2014 Line of storms that affected the terminals tonight has moved through as of this time, leaving strati-form rain and VCTS as the primary weather at our sites currently. This activity could last through 11Z at the Kansas City terminals, but should end sooner at KSTJ --09Z--. Otherwise, expect southerly winds to prevail for much of the day behind the exiting rain. There will be a returning threat for thunderstorms generally near and south of Kansas City again Monday afternoon, so have inserted VCTS in after 21Z. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...FLASH FLOOD WATCH until 10 AM CDT Monday FOR KSZ025-102>105. MO...FLASH FLOOD WATCH until 10 AM CDT Monday FOR MOZ001>005-011>014- 020>022-028>030-037. && $$ SHORT TERM...32 LONG TERM...MJ AVIATION...Cutter
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1123 PM CDT Sun Aug 31 2014 .UPDATE: Issued at 905 PM CDT Sun Aug 31 2014 Progressive UA trof and associated cold front, as well as outflow boundaries produced by intense convection so far this evening, should cause convection stretching from western Iowa to central KS to push across the NW half of our FA overnight. Rough timing based on extrapolation of upstream radar data suggests leading edge of precip moving into the Edina area by 05z/midnight. While we are missing much of today`s explicit guidance, from the data that is available believe that the latest HRRR output has a best handle on overnight trends in two aspects...being faster with the eastward progression and suggesting that some precip may be knocking on the western door of the STL metro by daybreak, and secondly more of a focus on late night/predawn convection over eastern KS/W MO where there should be good cold pool/low level jet interaction which should focus the most robust convection in this area. Forecast inherited from dayshift already trended specifics towards the trends mentioned above, so going forecast looks quite good and only minor adjustments needed to speed up onset of higher PoPs by 1-2 hours. If HRRR scenario does pan out I`m not too certain about how much of a severe weather threat will reach our area, but as mentioned by day shift there will likely be at least some impact from upstream outflows that propagate east and produce gusty winds. Specific trends for Labor Day and Monday night...including the potential for severe weather and heavy rain...will largely hinge on how convection evolves across the region during the predawn hours and into Monday morning; specifically how long the early morning convection lingers and where the associated outflow boundary will be located during the afternoon. While there is still quite a bit of uncertainty on how the convection will evolve, it certainly appears that outdoor plans may be altered in many areas due to the weather. Update will be issued as soon as 02x surface data can be ingested and assimilated into database. Truett && .SHORT TERM: (Through Late Tonight) Issued at 350 PM CDT Sun Aug 31 2014 Isolated to widely scattered thunderstorms over southeast portions of the CWFA should dissipate fairly quickly this evening. Until then, locally heavy downpours will continue over parts of the eastern Ozarks. Attention turns to tonight as a strong shortwave will move from eastern Wyoming into the eastern Nebraska/northwest Missouri. An MCS is expected to develop ahead of it on the nose of a 40kt low level jet over the eastern Plains. The model consensus keeps the vast majority of the precipitation over western/north central Missouri tonight. However, it does look like the leading edge will nose into central and northeast Missouri between 08Z and 12Z. Not sure how much of the strength of the storms by that point. Current thinking is that the cold pool may outrun the best forcing causing the MCS to weaken as it moves east. This scenario would have the rain moving into western portions of the CWFA between 08Z and 10Z. There may be some gusty winds as the outflow moves through, but the most significant impact would likely be locally heavy rain; and that looks more likely over western Missouri than in central Missouri. Carney .LONG TERM: (Monday through Next Sunday) Issued at 350 PM CDT Sun Aug 31 2014 We will see a break in what has been a hot pattern for us this past week, as the upper level ridge breaks down, thanks to a pair of decently strong shortwave TROFs. Much of the energy from these shortwaves will pass us to the north, but nevertheless, we are expecting high probabilities of rain from both of these systems because of either a favorable position of the low level jet or synoptic front and a very moist, deep warm-cloud atmosphere. The first system is expected to be ongoing early Monday morning for areas north and west of STL metro while in a slowly weakening state. This rain is expected to reach the STL metro area before dissipating or scattering out, with an anticipated boundary setup near or just south of the I-70 corridor for new development in the afternoon. There is also some potential for scattered development Monday afternoon further north and west near the synoptic front in northern MO and central IL. The second system on Monday night should make more of a pass to the south and interact with the synoptic front now deeper into our region and favorable axis of the low level jet. In addition, there is potential for localized heavy rainfall with PWs of around 2 inches and warm-cloud depths in excess of 4km and training storms. The front is then expected to stall over southern MO Tuesday before pushing north as a warm front on Wednesday with persistent, but lesser, chances for storms. While the humidity air never really goes away thru late week, it should be just cool enough to prevent any dangerous heat and humidity conditions until perhaps when the warm front pushes thru Wednesday and into Friday. A period of dry weather is anticipated Thursday through early Friday with a warm-sector setup, with the next, and what looks to be much stronger, cold front pushing thru late Friday thru early Saturday. Increased chances for rain will return with the front with all early indications showing a cool and dry period next weekend for most areas. TES && .AVIATION: (For the 06z TAFs through 06z Monday Night) Issued at 1103 PM CDT Sun Aug 31 2014 Convection extending from IA southwest through northwestern MO and KS just ahead of a cold front will drop southeastward into the UIN and COU areas late tonight, and then eventually into the St Louis metro area towards morning as it weakens. New convective development is expected late Monday afternoon and early evening mainly in COU and the St Louis metro area between the approaching cold front and an outflow boundary left from the late night/morning storm complex. S-sely surface winds late tonight will gradually veer around to a swly direction Monday morning. Specifics for KSTL: Weakening showers and storms are expected to drop southeastward into STL area by early Monday morning. There will be a break in the convection with redevelopment of storms expected late Monday afternoon and evening. S-sely surface winds late tonight wlll increase to around 14 kts by late Monday morning from a swly direction. GKS && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1050 PM EDT TUE SEP 2 2014 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL PUSH ACROSS THE NORTH COUNTRY THROUGH THE EVENING HOURS AHEAD OF A COLD FRONT. EXPECT LOCALLY HEAVY DOWNPOURS AND GUSTY WINDS WITH THE STRONGER STORMS. SUNNY, DRY AND COOLER WEATHER WILL LAST INTO THURSDAY. WARM SUMMER WEATHER RETURNS FRIDAY BUT WILL BE SHORT LIVED AS ANOTHER COLD FRONT SWEEPS IN EARLY SATURDAY GIVING A TASTE OF FALL-LIKE WEATHER FOR SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/... AS OF 1044 PM EDT TUESDAY...COLD FRONT CONTINUES TO MAKE ITS WAY EASTWARD ACROSS VERMONT LATE THIS EVENING...AND WILL EXIT THE FORECAST AREA BETWEEN 05Z-06Z. HEAVIEST PRECIPITATION WITH SOME EMBEDDED THUNDER ALONG THE COLD FRONT...WITH POST FRONTAL RAINS ACROSS REST OF VERMONT AND NORTHEAST NEW YORK ASSOCIATED WITH TRAILING MID LEVEL SHORTWAVE. MAIN THREAT THIS EVENING HAS BEEN HEAVY RAINFALL. HOWEVER...RAINFALL RATES IN HEAVIER PRECIPITATION HAVE DECREASED ENOUGH SO THAT THREAT OF FLASH FLOODING HAS DIMINISHED. HAVE MADE SOME MINOR ADJUSTMENTS TO FORECAST WITH LATEST UPDATE TO ACCOUNT FOR LATEST OBSERVATIONAL DATA AND TRENDS. EARLIER DISCUSSION... WELL, THE ATMOSPHERE IS FAIRLY PRIMED. VERY WARM AND HUMID AIRMASS IS RESULTING IN MODEST SURFACE BASED INSTABILITY (CAPE PUSHING 2000 J/KG AND LIFTED INDEX OF -2 TO -4C). SO FAR THE ACTIVITY HAS BEEN SPARSE ACROSS THE FORECAST AREA, HOWEVER RADAR SHOWS THE BUILDING LINE OF SHOWERS AND THUNDERSTORMS OUT ACROSS ONTARIO. THESE STORMS SHOULD BE CROSSING INTO THE UNITED STATES IN THE NEXT COUPLE OF HOURS. STILL LIKE HOW THE HRRR AND OUR LOCAL 6KM WRF ARE HANDLING THE EVOLUTION OF THE CONVECTION. STILL LOOKS LIKE AN ETA INTO THE CHAMPLAIN VALLEY DURING THE EVENING (LET`S GO WITH 6-8PM) AND THEN INTO EASTERN VERMONT BY 10PM. UPPER LEVEL SHORTWAVE WHICH IS THE PRIMARY TRIGGER FOR THE CONVECTION IS NOW OVER MICHIGAN AND STARTING TO LIFT NORTHEAST. OUT AHEAD OF THAT SHORT WAVE THE WIND FIELDS AND RELATED SHEAR INCREASE, BUT AT THE SAME TIME WE ARE GETTING CLOSER TO SUNSET AND LOSS OF HEATING. SO IT`S A BATTLE BETWEEN TIMING OF THE BEST DYNAMICS VS BEST INSTABILITY. AT THIS POINT STILL SEE NOTHING TO CHANGE THE IDEA THAT WE`LL HAVE AT LEAST A FEW STRONG T-STORMS AROUND, ESPECIALLY THIS EVENING AND MAINLY WEST OF THE GREEN MOUNTAINS. HAVE MAINTAINED THE IDEA OF GUSTY WINDS AND HEAVY RAIN AS THE PRIMARY THREATS. THE ACTIVITY WINDS DOWN BY MID EVENING IN THE ST LAWRENCE VALLEY TO JUST AFTER MIDNIGHT IN EASTERN VERMONT. DEPENDING ON HOW MUCH CLEARING WE GET, WE COULD HAVE A BIT OF PATCHY FOG LATE TONIGHT. THE COOLER AIR LAGS THE WEATHER A BIT, SO IT WILL STILL BE A MUGGY NIGHT WITH LOWS IN THE 60S. && .SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 355 PM EDT TUESDAY...IT WILL BE A QUIET 48 HOURS. SHORT TERM MODELS IN PRETTY GOOD AGREEMENT WITH REGARD TO RIDGING OVER THE REGION. DAILY SPECIFICS... WEDNESDAY: FLOW TURNS NORTHWEST DURING THE MORNING. 850MB TEMPERATURES FALL TO 11-12C WHICH WILL SUPPORT HIGH TEMPERATURES IN THE MID-UPPER 70S. WITH SOME WEAK COLD-AIR ADVECTION AND A GOOD DEAL OF SUN, WE`LL HAVE SOME EXCELLENT MIXING DURING THE AFTERNOON. WE SHOULD BE ABLE TO TAP SOME OF THE 20KT OR SO OF WIND THAT WILL BE A FEW THOUSAND FEET UP, SO IT SHOULD GET A LITTLE BREEZY IN THE AFTERNOON. WEDNESDAY NIGHT: HIGH PRESSURE OVERHEAD. CLEAR AND CALM, SO PATCHY FOG LOOKS LIKE A GOOD BET, ESPECIALLY SINCE THE GROUND WILL STILL BE A BIT DAMP FROM THE RAIN THIS EVENING. TEMPERATURES MAINLY IN THE 50S, THOUGH UPPER 40S POSSIBLE IN COLD SPOTS LIKE SARANAC LAKE. THURSDAY: SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE STILL NEARLY OVERHEAD, BUT STARTING TO PUSH EAST OF THE AREA. 850MB TEMPERATURES UP TO 12-13C, WHICH SUPPORTS UPPER 70S TO LOW 80S FOR HIGHS. PLENTY OF SUN AS WELL. THURSDAY NIGHT: DISCARDED THE NAM AS IT SEEMS TOO AGRESSIVE WITH THE LEADING EDGE OF WARM AIR ADVECTION AND PRODUCES THICKENING CLOUDS AND EVEN SOME LIGHT SHOWERS. THINK IT WILL REMAIN MOSTLY CLEAR AND DRY PER OTHER MODELS. HOWEVER WITH SOUTHWEST FLOW DEVELOPING, IT WON`T BE AS COLD, LOTS OF 50S AND EVEN LOW 60S FOR LOWS. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 350 PM EDT TUESDAY...EXTENDED PERIOD REMAINS PREDOMINATELY QUIET...LARGELY DOMINATED BY HIGH PRESSURE STARTING THE LATTER PART OF THE WEEKEND...BUT WET TO BEGIN. FOR THE START OF THE PERIOD...RISING HEIGHTS AND WARMING TEMPERATURES CONTINUE FRIDAY AS AN UPPER RIDGE CRESTS OVER THE NORTHEAST IN ADVANCE OF OUR NEXT SURFACE FRONT. MEAN 925MB TEMPS OF +20-23C WILL SUPPORT HIGHS WELL ABOVE NORMAL FOR EARLY SEPTEMBER WITH WIDESPREAD 80`S EXPECTED. IT`LL BE MUGGY TOO WITH DEWPOINTS RANGING THROUGH THE 60S WHICH WILL CREATE AMPLE SURFACE INSTABILITY TO SUPPORT SHOWER AND THUNDERSTORM DEVELOPMENT ALONG/AHEAD OF THE AFOREMENTIONED FRONT WHICH WILL SHIFT INTO THE BTV CWA LATE IN THE DAY AND THROUGH THE EVENING. STILL LOOKS LIKE THE BEST UPPER DYNAMICS PASSES TO OUR NORTH...WITH THE SURFACE BOUNDARY PARALLEL WITH UPPER FLOW SUPPORTING THE IDEA OF A SLOW EASTWARD PROGRESSION WHICH IS MAINTAINED BY THE LATEST ECMWF. GFS REMAINS A BIT FASTER PUSHING THE BOUNDARY THROUGH THE CWA BY SATURDAY MORNING SO HAVE CONTINUED ON WITH THE PREVIOUS FORECAST THINKING LEANING TOWARDS THE ECMWF. BY LATE SATURDAY TREND WILL BE TOWARDS CLEARER AND DRIER WEATHER AS THE UPPER FLOW TURNS ZONAL AND SURFACE HIGH PRESSURE BUILDS EASTWARD OUT OF THE CENTRAL CONUS. THIS HIGH THEN SLOWLY SHIFTS EAST THROUGH THE NORTHEAST AND OFF INTO THE CANADIAN MARITIMES BY LATE TUESDAY OFFERING A NICE STRETCH OF LATE SUMMER WEATHER. TEMPS RETURN TO MORE SEASONABLE LEVELS TO MAYBE SLIGHTLY BELOW NORMAL WITH EXPECTED HIGHS SATURDAY THROUGH TUESDAY IN THE UPPER 60S TO LOW 70S...AND LOWS IN THE MID 40S TO LOW 50S. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... THROUGH 00Z THURSDAY...VARIABLE FLIGHT CONDITIONS ACROSS THE FORECAST AREA THIS EVENING AS SHOWERS AND THUNDERSTORMS ALONG/AHEAD OF A COLD FRONT ADVANCE EASTWARD ACROSS FORECAST AREA THROUGH MIDNIGHT. CIGS WILL PRIMARILY REMAIN VFR BUT VSBY WILL BE REDUCED TO MVFR/IFR IN HEAVIER SHOWERS AND EMBEDDED STORMS. AFTER 06Z...PRECIP IS EAST OF THE REGION LEAVING GENERALLY CLOUDY SKIES. CIGS OVERNIGHT WILL GENERALLY BE VFR AT KMSS/KPBG/KBTV...BUT MVFR AT KRUT/KSLK/KMPV WITH POSSIBLE IFR AT KRUT UNDER BLOCKED FLOW. SOME PATCHY FOG ALSO POSSIBLE...ESPECIALLY AT KSLK/KMPV. AFTER 12Z...ALL CIGS LIFT TO VFR WITH SCT-BKN DIURNAL STRATOCUMULUS EXPECTED THROUGH THE DAY. OUTLOOK 00Z THURSDAY THROUGH SUNDAY... 00Z THU - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK. 00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS AND THUNDERSTORMS. 00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...NASH NEAR TERM...RJS/NASH SHORT TERM...NASH LONG TERM...LAHIFF AVIATION...RJS/LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
812 PM EDT TUE SEP 2 2014 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL PUSH ACROSS THE NORTH COUNTRY THROUGH THE EVENING HOURS AHEAD OF A COLD FRONT. EXPECT LOCALLY HEAVY DOWNPOURS AND GUSTY WINDS WITH THE STRONGER STORMS. SUNNY, DRY AND COOLER WEATHER WILL LAST INTO THURSDAY. WARM SUMMER WEATHER RETURNS FRIDAY BUT WILL BE SHORT LIVED AS ANOTHER COLD FRONT SWEEPS IN EARLY SATURDAY GIVING A TASTE OF FALL-LIKE WEATHER FOR SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/... AS OF 755 PM EDT TUESDAY...COLD FRONT MOVING THROUGH NORTHERN PORTION OF CHAMPLAIN VALLEY AT THIS TIME...WILL CONTINUE TO MAKE ITS WAY EAST THIS EVENING AND EXIT THE FORECAST AREA BETWEEN 04Z- 06Z. HEAVIEST PRECIPITATION WITH SOME EMBEDDED THUNDER ALONG THE COLD FRONT...WITH POST FRONTAL RAINS ACROSS NORTHERN NEW YORK ASSOCIATED WITH TRAILING MID LEVEL SHORTWAVE. MAIN THREAT THIS EVENING WILL BE HEAVY RAINFALL AND THREAT OF FLASH FLOODING...MAINLY FROM CHAMPLAIN VALLEY EASTWARD. ONLY MINOR ADJUSTMENTS MADE TO FORECAST WITH LATEST UPDATE. PREVIOUS DISCUSSION... WELL, THE ATMOSPHERE IS FAIRLY PRIMED. VERY WARM AND HUMID AIRMASS IS RESULTING IN MODEST SURFACE BASED INSTABILITY (CAPE PUSHING 2000 J/KG AND LIFTED INDEX OF -2 TO -4C). SO FAR THE ACTIVITY HAS BEEN SPARSE ACROSS THE FORECAST AREA, HOWEVER RADAR SHOWS THE BUILDING LINE OF SHOWERS AND THUNDERSTORMS OUT ACROSS ONTARIO. THESE STORMS SHOULD BE CROSSING INTO THE UNITED STATES IN THE NEXT COUPLE OF HOURS. STILL LIKE HOW THE HRRR AND OUR LOCAL 6KM WRF ARE HANDLING THE EVOLUTION OF THE CONVECTION. STILL LOOKS LIKE AN ETA INTO THE CHAMPLAIN VALLEY DURING THE EVENING (LET`S GO WITH 6-8PM) AND THEN INTO EASTERN VERMONT BY 10PM. UPPER LEVEL SHORTWAVE WHICH IS THE PRIMARY TRIGGER FOR THE CONVECTION IS NOW OVER MICHIGAN AND STARTING TO LIFT NORTHEAST. OUT AHEAD OF THAT SHORT WAVE THE WIND FIELDS AND RELATED SHEAR INCREASE, BUT AT THE SAME TIME WE ARE GETTING CLOSER TO SUNSET AND LOSS OF HEATING. SO IT`S A BATTLE BETWEEN TIMING OF THE BEST DYNAMICS VS BEST INSTABILITY. AT THIS POINT STILL SEE NOTHING TO CHANGE THE IDEA THAT WE`LL HAVE AT LEAST A FEW STRONG T-STORMS AROUND, ESPECIALLY THIS EVENING AND MAINLY WEST OF THE GREEN MOUNTAINS. HAVE MAINTAINED THE IDEA OF GUSTY WINDS AND HEAVY RAIN AS THE PRIMARY THREATS. THE ACTIVITY WINDS DOWN BY MID EVENING IN THE ST LAWRENCE VALLEY TO JUST AFTER MIDNIGHT IN EASTERN VERMONT. DEPENDING ON HOW MUCH CLEARING WE GET, WE COULD HAVE A BIT OF PATCHY FOG LATE TONIGHT. THE COOLER AIR LAGS THE WEATHER A BIT, SO IT WILL STILL BE A MUGGY NIGHT WITH LOWS IN THE 60S. && .SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 355 PM EDT TUESDAY...IT WILL BE A QUIET 48 HOURS. SHORT TERM MODELS IN PRETTY GOOD AGREEMENT WITH REGARD TO RIDGING OVER THE REGION. DAILY SPECIFICS... WEDNESDAY: FLOW TURNS NORTHWEST DURING THE MORNING. 850MB TEMPERATURES FALL TO 11-12C WHICH WILL SUPPORT HIGH TEMPERATURES IN THE MID-UPPER 70S. WITH SOME WEAK COLD-AIR ADVECTION AND A GOOD DEAL OF SUN, WE`LL HAVE SOME EXCELLENT MIXING DURING THE AFTERNOON. WE SHOULD BE ABLE TO TAP SOME OF THE 20KT OR SO OF WIND THAT WILL BE A FEW THOUSAND FEET UP, SO IT SHOULD GET A LITTLE BREEZY IN THE AFTERNOON. WEDNESDAY NIGHT: HIGH PRESSURE OVERHEAD. CLEAR AND CALM, SO PATCHY FOG LOOKS LIKE A GOOD BET, ESPECIALLY SINCE THE GROUND WILL STILL BE A BIT DAMP FROM THE RAIN THIS EVENING. TEMPERATURES MAINLY IN THE 50S, THOUGH UPPER 40S POSSIBLE IN COLD SPOTS LIKE SARANAC LAKE. THURSDAY: SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE STILL NEARLY OVERHEAD, BUT STARTING TO PUSH EAST OF THE AREA. 850MB TEMPERATURES UP TO 12-13C, WHICH SUPPORTS UPPER 70S TO LOW 80S FOR HIGHS. PLENTY OF SUN AS WELL. THURSDAY NIGHT: DISCARDED THE NAM AS IT SEEMS TOO AGRESSIVE WITH THE LEADING EDGE OF WARM AIR ADVECTION AND PRODUCES THICKENING CLOUDS AND EVEN SOME LIGHT SHOWERS. THINK IT WILL REMAIN MOSTLY CLEAR AND DRY PER OTHER MODELS. HOWEVER WITH SOUTHWEST FLOW DEVELOPING, IT WON`T BE AS COLD, LOTS OF 50S AND EVEN LOW 60S FOR LOWS. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 350 PM EDT TUESDAY...EXTENDED PERIOD REMAINS PREDOMINATELY QUIET...LARGELY DOMINATED BY HIGH PRESSURE STARTING THE LATTER PART OF THE WEEKEND...BUT WET TO BEGIN. FOR THE START OF THE PERIOD...RISING HEIGHTS AND WARMING TEMPERATURES CONTINUE FRIDAY AS AN UPPER RIDGE CRESTS OVER THE NORTHEAST IN ADVANCE OF OUR NEXT SURFACE FRONT. MEAN 925MB TEMPS OF +20-23C WILL SUPPORT HIGHS WELL ABOVE NORMAL FOR EARLY SEPTEMBER WITH WIDESPREAD 80`S EXPECTED. IT`LL BE MUGGY TOO WITH DEWPOINTS RANGING THROUGH THE 60S WHICH WILL CREATE AMPLE SURFACE INSTABILITY TO SUPPORT SHOWER AND THUNDERSTORM DEVELOPMENT ALONG/AHEAD OF THE AFOREMENTIONED FRONT WHICH WILL SHIFT INTO THE BTV CWA LATE IN THE DAY AND THROUGH THE EVENING. STILL LOOKS LIKE THE BEST UPPER DYNAMICS PASSES TO OUR NORTH...WITH THE SURFACE BOUNDARY PARALLEL WITH UPPER FLOW SUPPORTING THE IDEA OF A SLOW EASTWARD PROGRESSION WHICH IS MAINTAINED BY THE LATEST ECMWF. GFS REMAINS A BIT FASTER PUSHING THE BOUNDARY THROUGH THE CWA BY SATURDAY MORNING SO HAVE CONTINUED ON WITH THE PREVIOUS FORECAST THINKING LEANING TOWARDS THE ECMWF. BY LATE SATURDAY TREND WILL BE TOWARDS CLEARER AND DRIER WEATHER AS THE UPPER FLOW TURNS ZONAL AND SURFACE HIGH PRESSURE BUILDS EASTWARD OUT OF THE CENTRAL CONUS. THIS HIGH THEN SLOWLY SHIFTS EAST THROUGH THE NORTHEAST AND OFF INTO THE CANADIAN MARITIMES BY LATE TUESDAY OFFERING A NICE STRETCH OF LATE SUMMER WEATHER. TEMPS RETURN TO MORE SEASONABLE LEVELS TO MAYBE SLIGHTLY BELOW NORMAL WITH EXPECTED HIGHS SATURDAY THROUGH TUESDAY IN THE UPPER 60S TO LOW 70S...AND LOWS IN THE MID 40S TO LOW 50S. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... THROUGH 00Z THURSDAY...VARIABLE FLIGHT CONDITIONS ACROSS THE FORECAST AREA THIS EVENING AS SHOWERS AND THUNDERSTORMS ALONG/AHEAD OF A COLD FRONT ADVANCE EASTWARD ACROSS FORECAST AREA THROUGH MIDNIGHT. CIGS WILL PRIMARILY REMAIN VFR BUT VSBY WILL BE REDUCED TO MVFR/IFR IN HEAVIER SHOWERS AND EMBEDDED STORMS. AFTER 06Z...PRECIP IS EAST OF THE REGION LEAVING GENERALLY CLOUDY SKIES. CIGS OVERNIGHT WILL GENERALLY BE VFR AT KMSS/KPBG/KBTV...BUT MVFR AT KRUT/KSLK/KMPV WITH POSSIBLE IFR AT KRUT UNDER BLOCKED FLOW. SOME PATCHY FOG ALSO POSSIBLE...ESPECIALLY AT KSLK/KMPV. AFTER 12Z...ALL CIGS LIFT TO VFR WITH SCT-BKN DIURNAL STRATOCUMULUS EXPECTED THROUGH THE DAY. OUTLOOK 00Z THURSDAY THROUGH SUNDAY... 00Z THU - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK. 00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS AND THUNDERSTORMS. 00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...NASH NEAR TERM...RJS/NASH SHORT TERM...NASH LONG TERM...LAHIFF AVIATION...RJS/LAHIFF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1033 PM EDT TUE SEP 2 2014 .SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS CENTRAL NC ON WEDNESDAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM TUESDAY... CONVECTION HAS LARGELY DISSIPATED ACROSS THE AREA THIS EVENING WITH NOCTURNAL STABILIZATION TAKING HOLD. HOWEVER... AN APPROACHING LINE OF SHOWERS AND STORMS... CURRENTLY MOVING EAST-SOUTHEASTWARD THROUGH THE NC AND VA MOUNTAINS... IN ADVANCE OF A WEAK COLD FRONT IS EXPECTED TO APPROACH/POSSIBLY MOVE INTO PORTIONS OF THE AREA OVERNIGHT. WITH THE SPC MESOPAGE STILL SHOWING 1000-2000 J/KG OF MUCAPE ACROSS OUR NORTHWEST/NORTHERN PIEDMONT AND THE LATEST RAP AND HRRR SHOWING THE POTENTIAL FOR SOME OF THIS ACTIVITY TO MOVE INTO THIS AREA (NW/N PIEDMONT) WILL LEAVE A CHANCE OF SHOWERS AND STORMS IN THE FORECAST FOR THIS AREA. HOWEVER.. WITH THE LACK OF GOOD DEEP SHEAR AND DAYTIME HEATING THINK THIS LINE WILL CONTINUE TO SHOW A WEAKENING TREND AS IT MOVES INTO NW/N PORTIONS OF CENTRAL NC AROUND MIDNIGHT OR SHORTLY AFTER. THUS... WOULD EXPECT ANY OF THIS WEAKENING LINE TO REMAIN BELOW SEVERE LIMITS. WHERE HEAVY RAINFALL OCCURRED THIS PAST AFTERNOON-EVENING (GENERALLY ALONG AND SOUTH OF A LINE FROM ASHEBORO TO RALEIGH TO WILSON) AND SKIES PARTIALLY CLEAR OVERNIGHT... WE COULD SEE PATCHES OF FOG DEVELOP DURING THE PRE-DAWN HOURS OF WEDNESDAY. MIN TEMPS NEAR 70- LOWER 70S. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... AS OF 335 PM TUESDAY... SHEAR AXIS AND ATTENDANT SURFACE BOUNDARY WILL LIE ACROSS THE SOUTHERN COUNTIES OF CENTRAL NC. ISOLATED SHOWERS AND STORMS ALONG THIS FEATURE WEDNESDAY MORNING WILL GROW IN COVERAGE AS THE ATMOSPHERE HEATS UP...LEADING TO GREATER LOW LEVEL INSTABILITY. RELATIVELY WEAK STEERING FLOW SUGGEST THAT THE STORMS WILL BE SLOW MOVING. IF STORMS OCCUR OVER URBAN LOCATIONS...THIS MAY LEAD TO MINOR FLOODING OF STREETS AND POOR DRAINAGE AREAS. PLAN TO CAP POPS AT 50 PERCENT ACROSS THE SOUTH...DWINDLING TO 25-35 PERCENT ACROSS THE NW. MAX TEMPS WEDNESDAY DEPENDENT ON WHEN CONVECTIVE COVERAGE INCREASES AND WHETHER ANY PERIODS OF PARTIAL SUN OCCUR. BETTING ON SOME PARTIAL SUN INT HE LATE MORNING-EARLY AFTERNOON PRIOR TO CONVECTION INCREASING AFTER 2-3 PM. IF SKIES REMAIN OVERCAST OR CONVECTION BECOMES ACTIVE BY LUNCHTIME...MAX TEMPS MAY END UP BEING 5-6 DEGREES COOLER. CONTINUED WARM AND MUGGY WEDNESDAY NIGHT WITH SCATTERED CONVECTION SLOWLY DIMINISHING/DISSIPATING. MIN TEMPS NEAR 70-LOWER 70S. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 255 PM TUESDAY... FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT... PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL. FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC... ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING. WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING OVER THE CAROLINAS. -GIH && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 110 PM TUESDAY... SCATTERED SHOWERS AND STORMS CONTINUE ACROSS THE AREA... BUT ARE NOT CURRENTLY AFFECTING ANY TERMINALS. A FEW STORMS ARE POSSIBLE THROUGH THE OVERNIGHT HOURS AS A WEAK BOUNDARY APPROACHES THE AREA FROM THE NORTHWEST. SUB-VFR CONDITIONS WITH LOW CLOUDS/FOG ARE POSSIBLE EARLY WEDNESDAY AT KFAY AND KRWI WHERE LOW LEVEL MOISTURE REMAINS HIGH... PARTICULARLY AT KFAY WHERE 1-2 INCHES OF RAIN FELL THIS EVENING. SCATTERED CONVECTION WILL BE MORE PROMINENT WEDNESDAY AFTERNOON- EVENING...MAINLY ACROSS THE SOUTHERN COUNTIES INCLUDING IN VICINITY OF THE KFAY TERMINAL. OTHERWISE VFR CONDITIONS ARE EXPECTED TYPICAL SUMMERTIME WEATHER CONDITIONS ANTICIPATED THURSDAY THROUGH SATURDAY WITH AREAS OF EARLY MORNING FOG AND LOW CLOUDS GIVING WAY TO VFR CONDITIONS ASIDE FROM SUB-VFR CONDITIONS IN VICINITY OF SCATTERED AFTERNOON-EARLY EVENING CONVECTION. ON SUNDAY...A FRONT WILL BE APPROACHING FROM THE NW. THIS WEATHER SYSTEM WILL LIKELY ENHANCE THE PROBABILITY OF CONVECTION ACROSS CENTRAL NC. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BSD/WSS NEAR TERM...BSD/WSS SHORT TERM...WSS LONG TERM...HARTFIELD AVIATION...SEC/WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 PM EDT MON SEP 1 2014 .SYNOPSIS...AN AREA OF HIGH PRESSURE WILL EXTEND OVER THE REGION THROUGH TUESDAY. A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS CENTRAL NC ON WEDNESDAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 305 PM MONDAY... LATE THIS AFTERNOON THROUGH TONIGHT... SLIGHT TO MODERATELY UNSTABLE COVERS CENTRAL NC AT MID AFTERNOON WITH A WEAK SHEAR AXIS SLOWLY EDGING EASTWARD ACROSS THE REGION. BEST DYNAMICS/LIFT ASSOCIATED WITH THIS FEATURE WELL NORTH OF OUR REGION AS SHEAR AXIS IS IMPEDING UPON A MID-UPPER LEVEL RIDGE POSITIONED OVER EASTERN NC. THE RIDGE WILL CONTINUE TO INHIBIT MOST CONVECTIVE DEVELOPMENT BUT COULD STILL SEE AN ISOLATED STORM OR TWO DEVELOP ACROSS THE REGION. BASED ON 18Z MESO-ANALYSIS...ISOLATED CONVECTIVE DEVELOPMENT APPEARS TO BE FAVORED OVER THE WESTERN PIEDMONT...AND NEAR THE VIRGINIA BORDER COUNTIES. THIS SCENARIO HAS THE SUPPORT OF THE LATEST HRRR (WHICH HAS BEEN TRENDING WETTER). THE CONVECTIVE ALLOWING MODELS...THOUGH...HAVE BEEN TRENDING DRIER AND NOW SUGGEST THAT ISOLATED CONVECTION WILL OCCUR OUTSIDE OF OUR FORECAST AREA. WILL LIKELY SEE PATCHES OF FOG DEVELOP AFTER MIDNIGHT...MAINLY OVER THE COASTAL PLAIN..SANDHILLS AND EASTERN PIEDMONT. HOWEVER DENSE FOG WILL BE RARE WITH BULK OF THE VISIBILITIES AT OR ABOVE 1-2 MILES. MIN TEMPS OVERNIGHT NEAR 70-LOWER 70S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 305 PM MONDAY... TUESDAY AND TUESDAY NIGHT... MID-UPPER LEVEL RIDGE PROJECTED TO SLOWLY WEAKEN THIS PERIOD. THIS MAY ALLOW A FEW MORE T-STORMS TO DEVELOP IN THE SLIGHT-MODERATELY UNSTABLE AIR MASS TUESDAY AFTERNOON- EVENING. IN ADDITION...A S/W RESPONSIBLE FOR TRIGGERING THE CONVECTION ACROSS PARTS OF THE MISSOURI VALLEY/OZARKS THIS AFTERNOON- EVENING WILL APPROACH CENTRAL NC FROM THE NW LATE IN THE DAY. THIS FEATURE MAY TRIGGER ADDITIONAL ISOLATED-SCATTERED CONVECTION TUESDAY EVENING ACROSS THE NW PIEDMONT...AND OVERNIGHT TUESDAY INTO EARLY WEDNESDAY OVER THE REMAINDER OF CENTRAL NC. WHILE FORCING IS BETTER COMPARED TO THE PAST FEW DAYS...LIFT IS STILL CONSIDERED WEAK- MARGINAL AT BEST. THUS WILL LIMIT POPS TO NO HIGHER THAN LOW CHANCE. ANOTHER HOT DAY IN STORE FOR THE REGION. AFTERNOON THICKNESSES WILL REMAIN 20-25M ABOVE NORMAL...SUPPORTIVE OF HIGH TEMPS IN THE LOW-MID 90S UNDER FULL SUN CONDITIONS. WHEN THE HUMIDITY IS FACTORED IN...HEAT INDEX VALUES NEAR 100-104 WILL BE COMMON WITH THE HIGHEST H.I.VALUES IN THE SOUTHERN COASTAL PLAIN AND SANDHILLS. MIN TEMPS TUESDAY NIGHT GENERALLY IN THE LOWER 70S. -WSS FOR WED/WED NIGHT: THE WEAK SURFACE REFLECTION THAT REMAINS FROM THE COLD FRONT APPROACHING CENTRAL NC WILL BECOME EVEN MORE WASHED OUT AS IT SHIFTS INTO THE LEE TROUGH OVER CENTRAL NC. MODELS SHOW A VERY WEAK VORTICITY LOBE ASSOCIATED WITH THIS FRONT PUSHING ESE THROUGH NC EARLY WED... AND ITS APPROACH ALONG WITH LINGERING STRONG LOW LEVEL MOISTURE TRANSPORT OVER ERN NC SHOULD SUPPORT AN AREA OF ATYPICAL MORNING SHOWERS/STORMS OVER THE ERN AND ESPECIALLY SE CWA WED MORNING. THE DEPARTURE AND DAMPENING OF THE MEAN MID LEVEL TROUGH WELL TO OUR NE WILL RESULT IN MODEST RISING HEIGHTS (15-25 M) WITHIN THE FLAT (W-E ORIENTED) MID LEVEL RIDGE ACROSS NC THROUGH WED NIGHT. THE LATEST NAM RUN IS CONSISTENT WITH PREVIOUS RUNS IN BRINGING LOWER PW (UNDER 1.5") INTO MUCH OF THE CWA FROM THE NW WITH A BIT STRONGER 850-700 MB NW WIND AS COMPARED TO THE GFS... WHICH KEEPS PW VALUES UP TO 1.7-1.9". GIVEN THE FACT THAT THE MID LEVEL TROUGH WILL BE DAMPENING WITH LITTLE REASON TO SUPPORT A STRONG PUSH OF DRY AIR PAST THE MOUNTAINS... THE GFS`S MORE SUBDUED TROUGH INFLUENCE APPEARS MORE LIKELY... BASED ON THE PERSISTENCE OF THE STRONG RIDGE. MODERATE INSTABILITY IS EXPECTED OVER ALL BUT PERHAPS THE FAR NW... WITH THE GFS SHOWING MUCAPE PEAKING AT 1000-2500 J/KG. WILL STAY CLOSE TO THE GFS/ECMWF SOLUTION WITH SCATTERED AFTERNOON THROUGH EVENING STORMS... WITH BEST COVERAGE ACROSS THE SOUTHERN CWA AND ALONG/EAST OF THE PERSISTENT LEE TROUGH... AS WELL AS ALONG THE INLAND-TRACKING SEA BREEZE. WITH ABOVE-NORMAL PW AND WEAK MID LEVEL FLOW... SLOW-MOVERS AND HEAVY-RAINERS ARE POSSIBLE. WITH THICKNESSES A TAD LOWER THAN TUE BUT REMAINING 12-20 M ABOVE NORMAL... EXPECT WARM AND STICKY HIGHS OF 91-95... DESPITE A GOOD CHANCE OF DEBRIS CLOUD COVER THROUGH THE DAY. CONVECTION CHANCES SHOULD RECEDE WED NIGHT BUT THE GFS INDICATES PLENTY OF ELEVATED BUOYANCY POTENTIAL OVERNIGHT... INCLUDING MLCAPE OF 500-1000 J/KG RESULTING FROM VERY WARM 960-920 MB TEMPS. WILL HOLD ONTO CHANCE POPS MAINLY SOUTH HALF OVERNIGHT. MUGGY LOWS IN THE LOW-MID 70S. -GIH && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 230 PM MONDAY... FOR THU/FRI: CONTINUED ABOVE-NORMAL WARMTH WITH ONLY MINOR CHANGES IN AIR MASS. AT THE SURFACE... THE WEAK LEE TROUGH HOLDS THROUGH CENTRAL NC... ALONG WITH A HUMID AND SOMEWHAT STAGNANT AIR MASS. A POSITIVELY TILTED TROUGH SHIFTS THROUGH THE PACIFIC NORTHWEST AND SW CANADA INTO THE DAKOTAS THU... RESULTING IN BUILDING HEIGHTS AND GRADUAL MID LEVEL WARMING OVER THE SOUTHEAST STATES. THIS POLAR STREAM TROUGH THEN SHIFTS INTO ERN CANADA... WHILE THE FLAT RIDGE HOLDS ACROSS NC. WITH PLENTY OF LOW LEVEL MOISTURE POOLING... ISOLATED TO SCATTERED STORMS FOCUSED ALONG A SEA BREEZE OR SOME OTHER SUBTLE BOUNDARY REMAIN A GOOD BET... DESPITE THE WARMING TEMPS ALOFT. WILL RETAIN AFTERNOON AND EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A CATEGORY ABOVE NORMAL AS THICKNESSES STAY 10-15 M ABOVE NORMAL. FOR SAT THROUGH MON: A PATTERN TRANSITION IS LIKELY NEXT WEEKEND. THE INITIAL MID LEVEL TROUGH CONTINUES HEADING EASTWARD OVER ERN CANADA EARLY SAT... HOWEVER A SLUG OF STRONG VORTICITY EMANATING FROM A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE ON ITS HEELS... TAKING A COLD FRONT TO NEW ENGLAND AND THE OH VALLEY BY EARLY SAT. THE RESULTING TROUGH OVER ERN NOAM SUNDAY SHOULD HELP PUSH THE FRONT SOUTHWARD INTO NC... AFTER WHICH TIME IT IS APT TO LAY WEST/EAST AND STALL OVER THE CAROLINAS FOR LATE SUN THROUGH MON. THE GFS HAS A STRONGER/FASTER TIME FRAME THAN THE ECMWF... WITH THE FORMER MODEL SOLUTION TAKING THICKNESSES MUCH COLDER... UP TO 25 M BELOW NORMAL AS OPPOSED TO THE ECMWF WHICH IS BARELY 5 M BELOW NORMAL. TOUGH TO RESOLVE SUCH DIFFERENCES BUT GIVEN THE STRENGTH OF THE SRN CONUS RIDGE... AND THE FAR-NORTH TRACK OF THE POLAR LOW... I REMAIN SKEPTICAL ABOUT A STRONG COLD FRONTAL PASSAGE THROUGH NC. WILL STAY ON THE CONSERVATIVE SIDE OF THE TEMP TREND... WITH HIGHS/LOWS INITIALLY AROUND 90/AROUND 70 SAT... SLIPPING TO LOW-MID 80S/UPPER 60S BY MON. PRECIP CHANCES AND PATTERNS ARE LIKELY TO CHANGE LITTLE THROUGH SUN... PERHAPS INCREASING IN COVERAGE AS THE FRONT APPROACHES WITH FALLING HEIGHTS ALOFT... STRENGTHENING (YET STILL SOMEWHAT WEAK) MID LEVEL FLOW... AND A PERSISTENT CONFLUENT INFLUX OF GULF AND ATLANTIC MOISTURE IN THE LOW LEVELS. WILL MAINTAIN SCATTERED SHOWERS AND STORMS FOCUSED ON -- BUT NOT RESTRICTED TO -- AFTERNOON AND EVENING HOURS. WILL KEEP A CLIMO CHANCE POP ON MON... WITH LOWER THAN USUAL CONFIDENCE AS CONVECTION WILL GREATLY DEPEND ON WHETHER THE FRONT HOLDS UP ACROSS NC OR SHIFTS TO OUR SOUTH. -GIH && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 120 PM MONDAY... VFR CONDITIONS WILL CONTINUE ACROSS MUCH OF CENTRAL NC THROUGH TUESDAY NIGHT. THE EXCEPTION WILL BE A GOOD PROBABILITY OF EARLY STRATUS AND FOG (AND ASSOCIATED IFR/LIFR CONDITIONS)OCCURRING NEAR KRWI...KFAY AND POTENTIALLY NEAR KRDU. THE FOG/STRATUS WILL BE MOST LIKELY BETWEEN 09Z-12Z. ANY CONVECTION THIS AFTERNOON WILL BE LIMITED TO THE SEABREEZE WHICH MAY TRIGGER AN ISOLATED THUNDERSTORM NEAR OR SOUTH OF KGSB AND KRWI AND TO THE EAST-SE OF KFAY. THE SAME STORY WILL HOLD FOR TUESDAY AFTERNOON THOUGH AN ISOLATED THUNDERSTORM MAY OCCUR IN VICINITY OF KINT AND KGSO LATE IN THE DAY INTO THE EVENING HOURS. THE WEATHER PATTERN MAY BECOME A LITTLE MORE UNSETTLED WEDNESDAY AS A WEAK SURFACE BOUNDARY WILL DRIFT INTO CENTRAL NC. THIS FEATURE WILL SERVE AS A FOCUS FOR THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS...MAINLY IN THE AFTERNOON-EVENING HOURS. THIS BOUNDARY IS PROJECTED TO WEAKEN THURSDAY WHILE HIGH PRESSURE WILL BUILD BACK INTO THE REGION FRIDAY AND SATURDAY. OTHERWISE...THE OCCURRENCE OF EARLY MORNING FOG/STRATUS WILL CONTINUE THROUGH THE PERIOD. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...WSS/HARTFIELD LONG TERM...HARTFIELD AVIATION...WSS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1256 PM EDT MON SEP 1 2014 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL EXTEND OVER THE AREA THROUGH TUESDAY. A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE NORTH WEDNESDAY...THEN STALL AND DISSIPATE THURSDAY AND FRIDAY. HIGH PRESSURE RIDGES INTO THE REGION FROM OFFSHORE FRIDAY AND SATURDAY...THEN ANOTHER COLD FRONT WILL DROP INTO THE AREA LATE IN THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1230 PM MONDAY...MADE MINOR ADJUSTMENTS TO NEAR TERM WX/POP GRIDS. WITH THE LATEST MOS GUIDANCE AND HRRR MODEL HAVE DECREASED POPS MAINLY ACROSS THE COASTAL PLAINS. SHOULD STILL SEE SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG THE SEA BREEZE LATER THIS AFTERNOON. HIGHS ARE EXPECT TO BE IN THE LOW 90S INLAND TO MID 80S TO AROUND 90 NEAR THE COAST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... AS OF 330 AM MONDAY...WEAK SHRT WV MOVING ACROSS SUPPORTS ISOLD TSTM THREAT ALONG AND E OF HWY 17 OVERNIGHT...OTHERWISE A REPEAT OF WARM AND MUGGY CONDITIONS OF PAST FEW NIGHTS. MIN TEMPS FROM MID 70S INLAND TO NEAR 80 COAST. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AS OF 345 AM MON...THE UPPER RIDGE FLATTENS TUES INTO WED AS A STRONGER SHORTWAVE MOVES ACROSS THE OHIO RIVER VALLEY AND THROUGH NEW ENGLAND. MAINLY ISOL CONVECTION TUES WITH LIMITED FORCING BUT BETTER CHANCES WED AFTERNOON THROUGH THURS AS A BACKDOOR COLD FRONT DROPS INTO AND STALLS ACROSS THE AREA. UPPER LEVEL DYNAMICS REMAIN RATHER WEAK WITH THE CORE OF THE UPPER JET REMAINING WELL NORTH OF THE REGION BUT PLENTY OF MOISTURE WILL BE IN PLACE WITH MODERATE TO STRONG INSTABILITY TO ALLOW FOR SCT SHOWERS AND THUNDERSTORMS... ESPECIALLY INVOF THE FRONT WHERE BETTER SFC CONVERGENCE WILL RESIDE. SHEAR AND MID LEVEL LAPSE RATES REMAIN RATHER WEAK SO SEVERE CHANCES WILL REMAIN LOW BUT COULD SEE LOCALLY HEAVY PRECIP WITH WEAK STEERING FLOW AND HIGH PWATS. THE FRONTAL BOUNDARY DISSIPATES LATE THURS INTO FRI WITH HIGH PRES STRENGTHENING OFFSHORE AND UPPER RIDGING BUILDING ALOFT AND EXPECT MAINLY ISOLATED DIURNALLY DRIVEN CONVECTION FRI INTO SAT. THE UPPER RIDGE IS SUPPRESSED AGAIN LATE IN THE WEEKEND WITH ANOTHER SHORTWAVE TRAVERSING ACROSS THE GREAT LAKES INTO NEW ENGLAND WITH THE ATTENDANT BACKDOOR COLD FRONT MOVING INTO THE REGION SUN BRINGING BETTER CHANCES OF SHOWERS AND THUNDERSTORMS. LOW LEVEL THICKNESSES SUPPORT HIGHS IN THE LOW TO MID 90S THROUGH MUCH OF THE EXTENDED WHICH IS ABOUT 5 TO AS MUCH AS 10 DEGREES ABOVE CLIMO. WARMEST DAYS LOOK TO BE TUES AND WED WHEN LOW LEVEL THICKNESSES ARE GREATEST. SLIGHT COOLING THURS WITH GREATER CLOUD COVER...ESPECIALLY NORTHERN AREA WHERE NE/ELY FLOW EXPECTED NORTH OF THE BACKDOOR COLD FRONT...HOWEVER WINDS EXPECTED TO BE RATHER LIGHT. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... SHORT TERM /THROUGH 12Z TUESDAY/... AS OF 1 PM MON...VFR CONDITIONS WILL DOMINATE MOST OF THE TAF PERIOD UNDER HIGH PRESSURE. ISOLATED SHOWERS/THUNDERSTORMS MAY DEVELOP THIS AFTERNOON MAINLY AFFECTING THE COASTAL TAF SITES (EWN/OAJ). MAY AGAIN SEE SOME PATCHY FOG/STRATUS CONDITIONS LATE TONIGHT INTO THE EARLY MORNING HOURS...BRINGING CONDITIONS TO MVFR FOR ALL TAF SITES EXCEPT EWN. ANY FOG/STRATUS WILL START TO MIX OUT AFTER SUNRISE...BRING CONDITIONS BACK TO VFR. LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 345 AM MON...GENERALLY VFR CONDITIONS EXPECTED THROUGH THE LONG TERM ALTHOUGH PATCHY LIGHT FOG POSSIBLE DURING THE EARLY MORNING HOURS. ISOL-SCT CONVECTION POSSIBLE EACH DAY WITH BEST CHANCES WED THROUGH THURS AS A BACKDOOR FRONT DROPS INTO THE REGION. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 1230 PM MON...NO CHANGES TO FORECAST. THE LATEST BUOY OBS ARE SHOWING SW WINDS 5 TO 15 KTS WITH SEAS 2 TO 3 FEET. SW WINDS WILL CONTINUE UNDER THE PERSIST BERMUDA HIGH AND INLAND TROF PATTERN THROUGH THE PERIOD. SPEEDS WILL DIMINISH TO 10-15 KT THIS MORNING...THEN INCREASE TO 15-20 KT LATE AFTN INTO THIS EVENING...DIMINISHING AGAIN LATE TONIGHT. WW3 INITIALIZED BETTER WITH SEAS MAINLY AROUND 3 FT...AND ADJUSTED FCST ACCORDINGLY. HEIGHTS BUILDING TO AROUND 4 FT OUTER PORTIONS OF CENTRAL AND NRN WATERS THIS AFTN AND EVENING. LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 345 AM MON...THE BERMUDA HIGH OFFSHORE WILL BRING S/SW WINDS ACROSS THE WATERS INTO WED. WINDS GENERALLY AROUND 5-15 KT DURING LATE NIGHT AND MORNING HOURS BUT GRADIENTS TIGHTEN DURING THE AFTERNOON AND EVENING HOURS BOTH MON AND TUES AS THE PIEDMONT THERMAL TROUGH STRENGTHENS ALLOWING WINDS TO INCREASE TO AROUND 10-20 KT. A BACKDOOR FRONT DROPS INTO THE REGION WED THROUGH THURS BRINGING LIGHT WINDS...GENERALLY LESS THAN 10 KT. WINDS NORTH OF THE FRONT EXPECTED TO BE E TO NE WHILE REMAINING S/SW TO THE SOUTH. THE FRONT IS PROGGED TO DISSIPATE BY FRI WITH SLY FLOW AROUND 5-10 RETURNING TO ALL WATERS. MODELS IN GOOD AGREEMENT KEEPING SEAS AROUND 2-4 FT...LOCALLY TO 5 FT NEAR DIAMOND SHOALS...INTO EARLY WED BUT THEN SUBSIDE TO AROUND 2 FT THURS AND FRI WITH LIGHT WINDS ACROSS THE WATERS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JBM NEAR TERM...JBM/BM SHORT TERM...JBM LONG TERM...SK AVIATION...JBM/SK/BM MARINE...JBM/SK/BM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1129 PM CDT SUN AUG 31 2014 .UPDATE... ISSUED AT 1115 PM CDT SUN AUG 31 2014 NO MAJOR CHANGES PLANNED...SHOULD BE A DRY NIGHT. THERE COULD BE SOME PATCHY FOG WHERE SKIES CLEAR...BUT FOR NOW FEEL ITS NOT WORTH A MENTION WITH THE HRRR NOT INDICATING ANY LOW VSBYS...BUT SOMETHING FOR THE MID SHIFT TO WATCH. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 305 PM CDT SUN AUG 31 2014 AS OF 20Z...THE REGION IS IN A RELATIVELY QUIET PERIOD BETWEEN UPPER WAVES (ALTHOUGH AREAS OF DRIZZLE/LIGHT RAIN MAY BE PERSISTING). THE NEXT WAVE WILL PROPAGATE INTO THE REGION FROM THE SOUTHWEST...AND SPREAD SHOWERS INTO PORTIONS OF THE SOUTHERN FA. MOST GUIDANCE SUGGESTS COVERAGE WILL DISSIPATE AS THE STRONGER ACTIVITY INITIATES ACROSS NEBRASKA/IOWA. LATEST MESOSCALE ANALYSIS INDICATES MLCAPE AOA 1000 J/KG ALONG AND EAST OF A LINE FROM KBJI TO KBWP. HOWEVER...MLCIN IS STILL 60-80 J/KG...AND ANTICIPATE THIS AIRMASS TO BE EAST OF THE FA (AS MORE STABLE/DRIER AIR ADVECTS IN FROM THE WEST) BY THE TIME MLCIN IS WEAK ENOUGH FOR THUNDER INITIATION. STILL CANNOT RULE OUT AN ISOLD SHOWER/STORM THIS EVENING...BUT CHANCES APPEAR VERY LOW (AND HIGH RES MODELS AGREE). MUCH OF TONIGHT INTO MONDAY WILL BE DRY. HOWEVER...THE REGION DOES REMAIN IN GENERAL CYCLONIC FLOW ALOFT...AND THERE SHOULD BE WEAK UPPER WAVES ROTATING THROUGH THE REGION. DID INTRODUCE SLIGHT THUNDER CHANCES FOR MONDAY AFTERNOON/EVENING WHEN MODELS AGREE ON A STRONGER UPPER WAVE THAT WOULD INTERACT WITH WEAK INSTABILITY FROM DAYTIME HEATING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 305 PM CDT SUN AUG 31 2014 TUESDAY-WEDNESDAY...MUCH LIKE THE SHORT TERM PERIOD...WEAK UPPER WAVES IN THE UPPER FLOW PATTERN COULD LEAD TO PRECIP...BUT MOST AREAS SHOULD BE DRY A MAJORITY OF THE PERIOD. THE MAIN CONCERN WILL BE WEDNESDAY AFTERNOON AS MODELS INDICATE A WARM FRONTAL TYPE BOUNDARY LIFTING INTO WEST CENTRAL MINNESOTA...WHICH MAY LEAD TO STRONGER THUNDERSTORM POTENTIAL. WEDNESDAY NIGHT-SUNDAY...LONG TERM MODELS ARE IN GOOD AGREEMENT WITH OVERALL UPPER AIR PATTERN AND PLACEMENT OF PRECIP FOR MID WEEK CHANCES OF CONVECTION. BOTH MODELS SHOWING AN UPPER LOW/TROUGH OVER SRN SASK AROUND 06Z THU MOVE INTO WRN ONTARIO BY 00Z FRI. SW FLOW OVER THE DAKOTAS WILL BRING A CHANCE OF CONVECTION TO NORTHERN AND NORTHEASTERN ZONES WED NIGHT THROUGH THU NIGHT. NW FLOW THEN RETURNS WITH A COOL AND DRY AIRMASS IN PLACE...BRINGING COOLER THAN NORMAL TEMPS TO THE REGION. THIS DRY PERIOD SHOULD BE IN PLACE BY FRI AND CONTINUE THROUGH NEXT WKND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1115 PM CDT SUN AUG 31 2014 EXPECT VFR CONDITIONS WITH THE CHANCE OF SOME PATCHY FOG LATER TONIGHT WHERE IT CLEAR. FOR NOW WILL NOT MENTION ANY FOG...BUT SOMETHING TO KEEP IN MIND. THERE WILL BE A FEW SHOWERS AND STORMS MONDAY AFTERNOON MOVING FROM WEST TO EAST. WILL MENTION SOME VCSH IN THE 19-3Z TIMEFRAME...BUT HOLD OF ON THUNDER MENTION WITH FAIRLY ISOLATED COVERAGE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...DK SHORT TERM...TG LONG TERM...TG/SPEICHER AVIATION...DK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
921 PM EDT TUE SEP 2 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD NORTHEAST UP THE APPALACHIAN MOUNTAINS THROUGH WEDNESDAY NIGHT AND OFF THE EAST COAST BY THURSDAY NIGHT. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA THURSDAY FOLLOWED BY A COLD FRONT FRIDAY EVENING. HIGH PRESSURE WILL BUILD SOUTHEAST ACROSS THE REGION INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... CONVECTION WITH DIFFUSE COLD FRONT NOW REDUCED TO 3 SMALL CLUSTERS. VERY LITTLE LIGHTNING OCCURRING. RUC HANGS ON TO A FEW CELLS THRUT THE NIGHT SO WILL SLOW POP DROP OFF ENOUGH TO KEEP SLIGHT CHANCE GOING LONGER INTO THE NIGHT. MUCH OF THE CLOUD COVER FROM EARLIER IN THE DAY HAS DISSIPATED LEAVING PATCHY LOWER CLOUDS WITH BAND OF JET INDUCED CIRRUS ABOVE. WEAK COLD ADVECTION LOOKS EVEN MORE LIKELY TO NOT BE STRONG ENOUGH TO BRING IN THE DRIER AIR AS QUICK AS THOUGHT EARLIER SO WILL INCH LOWS UP EVEN ANOTHER DEG OVER THE SE 2/3 OF THE AREA. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/... BROAD UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA OVERNIGHT SETTING UP A ZONAL FLOW ACROSS THE COUNTRY ONCE AGAIN. SURFACE HIGH WILL BUILD NORTHEAST AND THEN EAST OF THE AREA BY WEDNESDAY NIGHT. WARM AIR ADVECTION WILL RESUME ON THURSDAY WITH A PRETTY GOOD SURGE OF WARM AIR RACING NORTHEAST INTO THE FORECAST AREA. 850 MB TEMPERATURES RISE FROM 16C WEDNESDAY NIGHT TO 20C BY FRIDAY. INCREASED DEW POINT AIR WILL RETURN AND BRING WITH IT HIGHER HUMIDITY ON FRIDAY. COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE REGION FRIDAY EVENING. CONVECTION IS EXPECTED TO REMAIN ASSOCIATED WITH THE COLD FRONT FRIDAY AFTERNOON INTO FRIDAY NIGHT. OTHERWISE...NO MAJOR THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED PERIOD UNTIL FRIDAY AFTERNOON. WILL HAVE TO KEEP AN EYE ON THE COLD FRONT FRIDAY FOR SEVERE POTENTIAL DUE TO IDEAL TIMING IN THE HEAT OF THE DAY. && .LONG TERM /SATURDAY THROUGH TUESDAY/... A SURFACE COLD FRONT WILL BE JUST ABOUT OUT OF THE AREA AT DAYBREAK SATURDAY. THERE COULD BE A FEW SHOWERS ALONG AND BEHIND THE FRONT BUT RAPID DRYING WILL OCCUR DURING THE AFTERNOON. READINGS NEXT WEEKEND WILL BE BACK BELOW NORMAL WITH LOWS MONDAY MORNING POSSIBLY GETTING INTO THE 40S. SUNDAY WILL BE A PLEASANT DAY WITH ABUNDANT SUNSHINE. THE FALL LIKE WEATHER WILL CONTINUE ON MONDAY. THE SURFACE HIGH RESPONSIBLE FOR THE QUIET WEATHER WILL EVENTUALLY MOVE OFF TO THE EAST ON TUESDAY ALLOWING WARMER SOUTHERLY FLOW TO RETURN. EXPECT TEMPS TUESDAY TO AVERAGE NEAR NORMAL. PRECIP CHANCES SHOULD HOLD OFF TILL JUST AFTER THE PERIOD ENDS. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... THE COLD FRONT WILL SAG ACROSS THE AREA THIS EVENING WITH A FEW MORE SHOWERS THAT MAY PRODUCE BRIEF MVFR CONDITIONS. THE DRIER AIR WILL BE SLOW TO FILTER IN AND THE WIND WILL BECOME LIGHT AND FOG IS LIKELY IN MANY AREAS BY DAYBREAK. STRATUS IS ALSO POSSIBLE... MAINLY AT INLAND SITES AND IFR CONDITIONS MAY OCCUR FOR SEVERAL HOURS INTO MID MORNING. THE FOG AND STRATUS SHOULD DISSIPATE...PERHAPS EVOLVING INTO A CUMULUS FIELD (SCT-BKN035-045) FOR A WHILE. VFR CONDITIONS SHOULD PREVAIL BY LATE MORNING EVERYWHERE. LAKE BREEZE WIND SHIFTS LIKELY AT KCLE AND KERI. OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY EVENING INTO SATURDAY WITH THE NEXT COLD FRONT. && .MARINE... A SURFACE COLD FRONT WILL MOVE EAST OF THE LAKE BY EARLY THIS EVENING. LINGERING SHOWERS OVER THE LAKE WILL ALSO BE GONE BY THAT TIME. EXPECT THE FLOW TO BECOME WESTERLY BEHIND THE FRONT AND THEN LIGHT AND VARIABLE OVERNIGHT. LIGHT FLOW WILL THEN CONTINUE WEDNESDAY WITH SOUTHERLY FLOW DEVELOPING ON THURSDAY AS A SURFACE RIDGE PUSHES EAST OF THE LAKE. SOUTH TO SOUTHWEST FLOW WILL THEN GRADUALLY INCREASE AHEAD OF A COLD FRONT THAT WILL DROP SOUTH ACROSS THE LAKE EARLY SATURDAY. MORE PRECIP IS LIKELY WITH THIS FRONT WITH THE FLOW BECOMING NORTH BEHIND IT. DO NOT THINK SPEEDS WILL BE STRONG ENOUGH FOR SMALL CRAFT HEADLINES. NORTHERLY FLOW WILL CONTINUE THROUGH SUNDAY. SPEEDS MOST IF NOT THE ENTIRE PERIOD WILL BE UNDER 15 KNOTS. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY/ADAMS SHORT TERM...LOMBARDY LONG TERM...KUBINA AVIATION...KOSARIK MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS TULSA OK
329 PM CDT MON SEP 1 2014 .DISCUSSION... A PROGRESSIVE...LOW AMPLITUDE SHORTWAVE TROUGH IS SLIDING EAST ACROSS THE NORTH CENTRAL PART OF THE COUNTRY TODAY. A PAIR OF EMBEDDED VORTICITY MAXIMA EXIST...ONE LIFTING QUICKLY NORTHEAST INTO THE GREAT LAKES...AND ANOTHER MOVING ACROSS WY ATTM. NORTHEAST OK/NORTHWEST AR LIES ON THE SOUTHERN FRINGE OF THE DECENT WESTERLY FLOW IN THE MID LEVELS. AT THE SURFACE...A MORE COMPLEX PATTERN EXISTS DUE TO OVERNIGHT CONVECTION THAT WAS MORE EXTENSIVE THAN FORECAST. THE OUTFLOW BOUNDARY FROM THAT CONVECTION HAS BEEN RETREATING NORTH DURING THE AFTERNOON AND IS APPROACHING THE KANSAS BORDER. MEANWHILE...THE SYNOPTIC COLD FRONT HAS BECOME NEARLY STATIONARY ACROSS CENTRAL AND SW KS. THE HRRR HAS BEEN CONSISTENT ALL DAY IN DVLPNG STORMS BTWN 22-00Z IN THE ZONE BTWN THE TWO BOUNDARIES. DIRECTIONAL/SPEED SHEAR SHOULD BE GREAT ENOUGH TO SUPPORT SUPERCELLS...ESPECIALLY GIVEN AVAILABLE CAPE. LOW LEVEL BACKED WINDS IN BTWN THE TWO BOUNDARIES SUGGESTS...IF A SUPERCELL CAN GET GOING...THAT A LARGE HAIL/TORNADO RISK EXISTS BEFORE CELLS GRADUALLY CONGEAL INTO CLUSTERS AND THEN MOVE E/SE THIS EVENING...WHEN THE MAIN THREAT BECOMES DAMAGING WINDS. MORE DEVELOPMENT IS FORECAST BY THE HRRR LATER TONIGHT NORTH OF THE EFFECTIVE BOUNDARY. THERE WILL BE A SHARP CUTOFF AS YOU GO SOUTH WHERE RAIN FALLS AND WHERE IT DOESN`T...GIVEN STRONG CAP IN PLACE DUE TO EML. I BACKED OFF SOME ON LOWS TONIGHT ACROSS THE NE OK AND NW AR GIVEN POTENTIAL FOR CONVECTIVELY COOLED OUTFLOW...MUCH LIKE LAST NIGHT. RAIN/STORM CHANCES WILL CONTINUE INTO TUESDAY MAINLY ACROSS NE OK/NW AR NEAR AND NORTH OF THE EFFECTIVE BOUNDARY...WHICH WILL BEGIN TO RETREAT AGAIN TOMORROW AND ESPECIALLY TOMORROW NIGHT. THE BEST CHANCES FOR RAIN/STORMS TUESDAY NIGHT WILL BE NORTH AND EAST OF TULSA IN THE WARM ADVECTION REGIME. PRECIP CHANCES COME TO AN END WEDNESDAY AS THE BOUNDARY LIFTS NORTH OF THE REGION AND MID LEVEL HEIGHTS RISE. GUSTY SOUTHWEST WINDS WILL PUSH TEMPS BACK INTO THE UPPER 90S WEDNESDAY AFTERNOON ACROSS NE OK. THE DETERMINISTIC RUNS OF THE GFS/ECMWF TODAY ARE SLOWER WITH THE FRONT TOWARD THE END OF THE WEEK...GFS MORE SO THAN THE ECMWF. NEVERTHELESS...POPS WILL BE CARRIED FRIDAY AND SATURDAY...GRADUALLY TAPERING OFF SUNDAY. TEMPS WILL FALL BACK INTO THE 80S FOR HIGHS AND 60S FOR LOWS. THE RATHER ACTIVE PATTERN ACROSS THE NORTHERN TIER OF STATES CONTINUES INTO NEXT WEEK...AS ANOTHER STRONG SYSTEM MOVES ACROSS THE NORTHERN PART OF THE COUNTRY. AN EVEN STRONGER FRONT COULD BE ON THE WAY IN ABOUT 10 DAYS...A SIGN OF THE CHANGE IN SEASONS. LACY && .PRELIMINARY POINT TEMPS/POPS... TUL 71 91 75 96 / 60 40 20 10 FSM 75 91 73 94 / 30 40 20 10 MLC 77 93 76 93 / 30 30 10 10 BVO 69 90 69 96 / 60 40 30 10 FYV 71 86 69 91 / 60 50 30 20 BYV 71 86 69 91 / 60 50 30 20 MKO 73 90 72 93 / 50 40 20 10 MIO 71 88 72 94 / 60 40 40 10 F10 74 92 74 93 / 40 30 20 10 HHW 75 94 74 95 / 10 10 10 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ LONG TERM....30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
815 PM EDT TUE SEP 2 2014 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING. HIGH PRESSURE WILL BUILD ALONG THE EAST COAST LATE THIS WEEK...THEN ANOTHER COLD FRONT WILL LIKELY PUSH SOUTH ACROSS THE REGION BY SATURDAY. && .NEAR TERM /THROUGH WEDNESDAY/... SENT ANOTHER UPDATE TO BEGIN TRIMMING BACK THE WATCH AS THE LINE MOVES INTO CENTRAL PA. MAIN LINE OF CONVECTION EXTENDS FROM SULLIVAN COUNTY BACK TO SOUTHERN CAMBRIA. OVERALL THE ACTIVITY SEEMS TO BE WEAKENING. IF THIS TREND CONTINUES...WE WILL CONTINUING CANCELING COUNTIES OUT OF THE WATCH. BIGGER QUESTION SWITCHES TO HOW MUCH ADDITIONAL CONVECTION WE CAN EXPECT FOR THE REMAINDER OF THE EVENING IN THE AREAS WORKED OVER BY THE EARLIER LINE OF STORMS. LATEST HRRR SHOWS ACTIVITY DROPPING OFF SMARTLY AFTER SUNDOWN SO I HAVE STARTED LOWERING THE EVENING AND OVERNIGHT POPS. DRIER AIR BEHIND THE COLD FRONT WILL REPLACE THE SULTRY LATE SEASON HUMIDITY WE HAVE EXPERIENCED FOR THE LAST SEVERAL DAYS. IT WILL STILL BE RATHER MILD WITH LOWS IN THE 60S. CLEARING SKIES...A LIGHT WIND WIND AND WET GROUND WILL LIKELY LEAD TO AREAS OF FOG LATE TONIGHT. HIGH PRES AND ASSOC DRIER AIR MASS WILL BE OVR THE AREA WEDNESDAY...SUPPLYING MSUNNY AND WARM CONDS. ENS MEAN 8H TEMPS NR 15C SHOULD SUPPORT MAX TEMPS FROM THE M70S NW MTNS TO THE M80S IN THE SUSQ VALLEY. && .SHORT TERM /WEDNESDAY NIGHT/... IT WILL CONTINUE FAIR WEDNESDAY NIGHT WITH LITTLE MORE THAN AREAS OF LATE NIGHT FOG AS THE ONLY REAL SENSIBLE WEATHER. && .LONG TERM /THURSDAY THROUGH TUESDAY/... SUBTROPICAL RIDGE CENTERED OVER THE CAROLINAS WILL BE SUPPRESSED BY SHORTWAVE ENERGY AND MODERATE-INTENSITY SFC CYCLONE TRACKING NEWD FROM THE NRN HIGH PLAINS ACROSS WRN ONTARIO INTO NRN QUEBEC THU THRU SAT. ITS TRAILING COLD FRONT REMAINS THE FOCUS FOR PCPN HEADING INTO THE WEEKEND WITH CONTINUED UNCERTAINTY IN THE SEWD FRONTAL PROGRESSION. A SLOWER TREND MAY BE EMERGING IN THE 12Z GFS/GEFS WITH ITS FRONTAL ZONE ALIGNING CLOSER WITH THE ECMWF/GEM BY 00Z SUN. MAX POPS SHIFT FROM NW TO SE OVER THE CWA FROM 00Z SAT TO 00Z SUN. AHEAD OF CDFRONT...TEMPS ARE LIKELY TO PEAK ON FRIDAY WITH MEAN H85 TEMPS +18-20C SUPPORTING WIDESPREAD HIGHS 85-90F. THE NEXT QUESTION CONCERNS HOW QUICKLY THE FRONT CLEARS SRN PA ON SUNDAY WITH MODEL DATA SUGGESTING THE UPPER LEVEL FRONT HANGS BACK ALONG THE APPLCHNS/MID-ATLC PIEDMONT...AS ENERGY IS SHEARED NEWD THRU THE NRN NEW ENGLAND AND CANADIAN MARITIMES AND FLOW ALOFT BECOMES ORIENTED MORE WESTERLY. MEAN PW FIELDS SHOW DRIER AIR SPREADING INTO THE REGION FROM THE NW BEHIND THE FRONT AS HIGH PRES BECOMES ESTABLISHED IN THE NORTHEAST BY EARLY NEXT WEEK. THEREFORE EXPECT TEMPS AND POPS TO TREND LOWER DURING THE LATER PERIODS. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... THIN LINE OF SHRA MOVING S/SE WILL LIKELY CONTINUE TO WEAKEN AS IT APPROACHES KMDT AND KLNS. A BRIEF BIT OF CLEARING WILL DO WONDERS TO MAKE CONDITIONS DETERIORATE OVER THE NEXT FEW HOURS. THE HIGH MOISTURE AND LIGHT WEST WINDS WILL LIKELY LEAD TO FOG/LOW CLOUDS FORMING OVER AT LEAST BFD AND JST. THE REST OF THE TERMINALS WILL ALSO FOG UP THROUGH THE NIGHT...WITH LIFR FOG POSSIBLE AT MANY LOCATIONS. SINCE HIGH PRESSURE WILL BE OVERHEAD VIS/CIG IMPROVEMENTS WILL HAPPEN SLOWLY DURING THE MORNING - ESP WHERE THE LOW CLOUDS RESIDE. THE LESS-CLOUDY AREAS IN THE EAST WILL HAVE THE FOG DISSIPATE BEFORE THE LOW CLOUDS IN THE WEST BREAK UP. THERE COULD BE SOME TALLER CU IN THE SRN TIER IN THE AFTERNOON THANKS TO ALL THE MOISTURE. SOME LOW STRATUS MAY FORM WED NIGHT AS THE FLOW BECOMES SOUTHERLY. A COUPLE OF SHOWERS ARE POSSIBLE THURS AFTERNOON AS HEATING POPS BIGGER CU OFF THE HIGH TERRAIN - ESP IN THE S/E. FOG IS EXPECTED THURSDAY MORNING AS WELL...BUT IT SHOULD NOT BE AS WIDESPREAD AS TONIGHT. OUTLOOK... FRI...MAINLY VFR. CHC OF PM TSTMS WEST. SAT...VFR/MVFR WITH SCT SHWRS/TSTMS. COLD FROPA. SUN...AM FOG. OTHERWISE VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...FITZGERALD LONG TERM...STEINBUGL AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
751 PM EDT TUE SEP 2 2014 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING. HIGH PRESSURE WILL BUILD ALONG THE EAST COAST LATE THIS WEEK...THEN ANOTHER COLD FRONT WILL LIKELY PUSH SOUTH ACROSS THE REGION BY SATURDAY. && .NEAR TERM /THROUGH WEDNESDAY/... SENT ANOTHER UPDATE TO BEGIN TRIMMING BACK THE WATCH AS THE LINE MOVES INTO CENTRAL PA. MAIN LINE OF CONVECTION EXTENDS FROM SULLIVAN COUNTY BACK TO SOUTHERN CAMBRIA. OVERALL THE ACTIVITY SEEMS TO BE WEAKENING. IF THIS TREND CONTINUES...WE WILL CONTINUING CANCELING COUNTIES OUT OF THE WATCH. BIGGER QUESTION SWITCHES TO HOW MUCH ADDITIONAL CONVECTION WE CAN EXPECT FOR THE REMAINDER OF THE EVENING IN THE AREAS WORKED OVER BY THE EARLIER LINE OF STORMS. LATEST HRRR SHOWS ACTIVITY DROPPING OFF SMARTLY AFTER SUNDOWN SO I HAVE STARTED LOWERING THE EVENING AND OVERNIGHT POPS. DRIER AIR BEHIND THE COLD FRONT WILL REPLACE THE SULTRY LATE SEASON HUMIDITY WE HAVE EXPERIENCED FOR THE LAST SEVERAL DAYS. IT WILL STILL BE RATHER MILD WITH LOWS IN THE 60S. CLEARING SKIES...A LIGHT WIND WIND AND WET GROUND WILL LIKELY LEAD TO AREAS OF FOG LATE TONIGHT. HIGH PRES AND ASSOC DRIER AIR MASS WILL BE OVR THE AREA WEDNESDAY...SUPPLYING MSUNNY AND WARM CONDS. ENS MEAN 8H TEMPS NR 15C SHOULD SUPPORT MAX TEMPS FROM THE M70S NW MTNS TO THE M80S IN THE SUSQ VALLEY. && .SHORT TERM /WEDNESDAY NIGHT/... IT WILL CONTINUE FAIR WEDNESDAY NIGHT WITH LITTLE MORE THAN AREAS OF LATE NIGHT FOG AS THE ONLY REAL SENSIBLE WEATHER. && .LONG TERM /THURSDAY THROUGH TUESDAY/... SUBTROPICAL RIDGE CENTERED OVER THE CAROLINAS WILL BE SUPPRESSED BY SHORTWAVE ENERGY AND MODERATE-INTENSITY SFC CYCLONE TRACKING NEWD FROM THE NRN HIGH PLAINS ACROSS WRN ONTARIO INTO NRN QUEBEC THU THRU SAT. ITS TRAILING COLD FRONT REMAINS THE FOCUS FOR PCPN HEADING INTO THE WEEKEND WITH CONTINUED UNCERTAINTY IN THE SEWD FRONTAL PROGRESSION. A SLOWER TREND MAY BE EMERGING IN THE 12Z GFS/GEFS WITH ITS FRONTAL ZONE ALIGNING CLOSER WITH THE ECMWF/GEM BY 00Z SUN. MAX POPS SHIFT FROM NW TO SE OVER THE CWA FROM 00Z SAT TO 00Z SUN. AHEAD OF CDFRONT...TEMPS ARE LIKELY TO PEAK ON FRIDAY WITH MEAN H85 TEMPS +18-20C SUPPORTING WIDESPREAD HIGHS 85-90F. THE NEXT QUESTION CONCERNS HOW QUICKLY THE FRONT CLEARS SRN PA ON SUNDAY WITH MODEL DATA SUGGESTING THE UPPER LEVEL FRONT HANGS BACK ALONG THE APPLCHNS/MID-ATLC PIEDMONT...AS ENERGY IS SHEARED NEWD THRU THE NRN NEW ENGLAND AND CANADIAN MARITIMES AND FLOW ALOFT BECOMES ORIENTED MORE WESTERLY. MEAN PW FIELDS SHOW DRIER AIR SPREADING INTO THE REGION FROM THE NW BEHIND THE FRONT AS HIGH PRES BECOMES ESTABLISHED IN THE NORTHEAST BY EARLY NEXT WEEK. THEREFORE EXPECT TEMPS AND POPS TO TREND LOWER DURING THE LATER PERIODS. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... GENERALLY VFR CONDITIONS ACROSS CENTRAL PA AT 18Z. BUT SOME RESTRICTIONS ARE IN STORE FOR THIS AFTERNOON AND EVENING...ESP ACROSS THE NORTH AND CENTRAL MTNS...AS A SHORTWAVE WITH INCREASING MID LEVEL FLOW TRIGGERS A LINE OF SHOWERS/TSTMS. MOST WIDESPREAD IMPACTS WILL BE ACROSS NORTHERN PA /GENERALLY NORTH OF I-80/ WITH A MORE SOLID LINE OF CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THOUGH SCATTERED TSTMS ALSO POSS FURTHER SOUTH. THE STRONGEST STORMS COULD PRODUCE DAMAGING WIND GUSTS AND SIGNIFICANT REDUCTIONS AT AIRFIELDS AS THEY PASS THROUGH. STORMS SHOULD CLEAR THE WESTERN HALF BY 22-24Z AND THE EAST BY 01-03Z. THEN CLEARING SKIES...A LIGHT WIND AND WET GROUND WILL LIKELY LEAD TO AREAS OF FOG LATE TONIGHT. OUTLOOK... WED-THU...PATCHY AM FOG...OTHERWISE VFR. FRI...MAINLY VFR. CHC OF PM TSTMS WEST. SAT...VFR/MVFR WITH SCT SHWRS/TSTMS ASSOCD WITH COLD FROPA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...FITZGERALD LONG TERM...STEINBUGL AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
343 PM EDT MON SEP 1 2014 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL CONTINUE INTO TUESDAY UNTIL A COLD FRONTAL PASSAGE BRINGS DRIER AND SLIGHTLY COOLER AIR TO CENTRAL PENNSYLVANIA THROUGH MID WEEK. HUMIDITY WILL RETURN TOWARD THE END OF THE WEEK AHEAD OF THE NEXT FRONTAL SYSTEM THAT WILL BRING THE CHANCE OF RAIN FOR THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 18Z...RADAR LOOP INDICATES CONVECTIVE PCPN IS STARTING TO INCREASE IN CVRG OVER THE LAST 30 MINUTES OVER THE SRN 1/3 OF THE CWA WHERE THE RAP SHOWS THE HIGHEST CAPE IN PA. EVEN BETTER INSTABILITY CAN BE FOUND SOUTH OF THE MASON DIXON LINE NEAR THE I95 CORRIDOR WHERE THE FIRST LTG STRIKE OF THE AFTN HAS BEEN DETECTED. HIGHEST POPS /30-40%/ HAVE BEEN PAINTED OVER THE SRN TIER ZONES THRU THE EARLY EVENING HOURS. FURTHER TO THE NORTH...WEAK LG SCALE FORCING COUPLED WITH MARGINAL INSTABILITY /HINDERED BY CLOUD COVER/ AND VERY MOIST/HUMID AIRMASS CONTINUES TO SUPPORT IDEA OF MAINLY ISOLD SHOWERS. MESO MDL GUIDANCE SHOWS EVE STORMS EVENTUALLY DISSIPATING AFTER DARK WITH THE LOSS OF HEATING. UPSTREAM STORMS OVER THE GRT LWR MI/OH VLY SHOULD ALSO EXHIBIT A CONSIDERABLE WEAKENING TREND AS THE EVOLVE EWD AND MAY SURVIVE INTO WRN PA LATE TNGT. MAIN FOCUS WILL SHIFT TO THE WEST TONIGHT AS A WELL-DEFINED COLD FRONT APPROACHES THE AREA FROM THE N/W. HIGHEST POPS /40-50%/ WILL BE OVER THE FAR NW MTNS BASED ON MULTI-MODEL ENSEMBLE CONSENSUS QPF. IT WILL BE MUGGY WITH LOWS 65-70F. LGT WINDS AND HI DEWPOINTS ALONG WITH SOME PARTIAL CLEARING FAVORS SOME LOW CLOUDS/FOG. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... A RELATIVELY LOW AMPLITUDE SHORTWAVE TROUGH WILL SLIDE EWD FROM THE GREAT LAKES/MIDWEST INTO NRN NEW ENGLAND BY THE END OF THE PERIOD. THIS FEATURE WILL DRIVE A WELL-DEFINED COLD FRONT /WITH SHARP MSTR-PW GRADIENT/ SEWD FROM THE LWR LKS/OH VLY ACRS THE N-CNTRL APPALACHIANS. A CONDITIONAL RISK FOR STRONG TO ISOLATED SEVERE STORMS WILL EXIST FROM LATE TUE MORNING THROUGH THE AFTERNOON WITH THE PRIMARY POTNL TSTM HAZARD BEING DAMAGING WINDS. CLOUD COVER FROM UPSTREAM CONVECTION LKLY ONGOING AT 12Z ALONG WITH RESIDUAL OVERNIGHT LOW STRATUS/FOG SHOULD ACT TO LIMIT DESTABILIZATION EARLY TOMORROW. ALTHOUGH 700-500MB LAPSE RATES WILL GENERALLY REMAIN WEAK TO POOR...THE MODELS SHOW A BELT OF STRONGER WESTERLY MID-LVL FLOW AND DEEP LYR SHEAR. THIS SHOULD HELP TO SUPPORT AN INCREASE IN CONVECTIVE PCPN/INTENSITY AS RENEWED DEVELOPMENT OCCURS ALONG OUTFLOWS/DIFFERENTIAL HEATING ZONES BY LATE MORNING INTO THE AFTERNOON...WITH SOME ORGANIZATION INTO LINE SEGMENTS/CLUSTERS. THIS SHOULD YIELD AT LEAST AN ISOLD DMGG WIND THREAT...WARRANTING AN UPGRADE BY SPC TO A CATEGORICAL /SLGT/ RISK DESIGNATION. THIS HAS BEEN REFLECTED IN AN UPDATED HWO. EARLY CLOUDS SHOULD BREAK FOR A WARM AND HUMID DAY WITH FCST HIGHS EXPECTED TO RANGE FROM THE MID 70S OVER THE NW TO NEAR 90 OVER THE LOWER SUSQ VLY. THE SECOND HALF OF THE PERIOD ESPECIALLY AFTER MIDNIGHT SHOULD FEATURE A COOLER/DRYING TREND BEHIND THE FRONT WITH PWS FALLING AOB NORMAL BY 12Z WED. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... COLD FRONT EXITING TO THE EAST TUE NIGHT ALONG WITH NORTHWEST FLOW AROUND BUILDING HIGH PRESSURE AREA OVER OHIO VALLEY WILL BRING A TRANSITION TO A NOTICABLY DRIER AIRMASS FOR MIDWEEK. DAYTIME HIGHS WILL REMAIN SLIGHTLY ABOVE NORMAL...BUT LOWER DEWPOINTS WILL MAKE IT FEEL MORE COMFORTABLE. OVERNIGHT LOWS WED NIGHT WILL DIP TO NEAR 50F IN THE NORTHERN MTNS TO AROUND 60F IN THE SE. THE HIGH WILL MOVE OFF THE EAST COAST THU INTO FRI...ALLOWING MORE HUMID AIR TO BEGIN RETURNING TO THE REGION. A SURFACE LOW SLIDES FROM THE NORTHERN PLAINS ACROSS THE GREAT LAKES AND LIFTING INTO S CANADA ON FRI...DRAGGING A COLD FRONT ALONG BEHIND. AS THIS FRONT APPROACHES...AN AREA OF HIGHER PWATS /1-2"/ SURGES INTO THE OHIO VALLEY...AND THEN INTO PA FRI NIGHT INTO SAT. AT SAME TIME A BROAD UPPER TROUGH SAGS SOUTHWARD. THIS WILL BRING ELEVATED CHANCES FOR SHOWERS/TSTMS STARTING FRI NIGHT IN THE NW AND SPREADING AREAWIDE ON SAT. BEHIND THE FRONT...AIRMASS CHANGE WILL USHER IN MUCH COOLER AND DRIER AIR FOR LATE WEEKEND INTO EARLY NEXT WEEK. HIGHS WILL FALL BACK ABOUT 10F...RANGING FROM THE UPPER 60S TO MID 70S. AS LARGE HIGH PRESSURE AREA TRACKS ACROSS NEW ENGLAND...MORNING LOWS SHOULD DIP WELL INTO THE 40S ACROSS THE NORTHERN MTNS...AND IN THE LOWER TO MID 50S ACROSS THE SOUTH. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... 18Z...CIGS/VISBYS HAVE IMPROVED TO VFR OR MVFR AS EXPECTED. HOWEVER DESPITE A GENERAL INCREASE IN SHOWER ACTIVITY THERE IS STILL LOW CONFIDENCE IN POINT TERMINAL IMPACTS. EVOLUTION OF CONVECTIVE ACTIVITY AND COLLOCATION OF BEST INSTABILITY SUGGESTS THE SRN TAFS HAVE THE BEST CHC TO SEE SCT SHOWERS OR A BRIEF TSRA DOWNPOUR. HAVE ADDED SOME 1HR TEMPS THRU 19Z WITH SHOWERS MOVG THRU AOO/UNV. OTHER CONCERN WILL BE CLOUD TRENDS OVERNIGHT WITH MOIST AIRMASS LKLY PROMOTING ANOTHER PERIOD OF LOW CIGS/FOG INTO TUE MORNING. A COLD FRONT MOVG EWD THRU THE MIDWEST WILL ALSO BRING THE CHC FOR SOME SHOWERS TO REACH THE NW 1/4 TO 1/3 OF THE AIRSPACE BY EARLY TUE MORNING. THIS FRONT WILL BE A FOCUS FOR SCT-NMRS SHWRS/TSTMS TUES AFTN-EVE AS IT MOVES SEWD ACRS CENTRAL PA. THE RECENT GUIDANCE SUGGESTS A SLIGHTLY HIGHER PROBABILITY FOR LCL SVR STORMS AND AT LEAST AN ISOLD THREAT FOR DAMAGING TSTM WIND GUSTS. OUTLOOK... WED-THU...PATCHY AM FOG...OTHERWISE VFR. FRI...MAINLY VFR. CHC OF PM TSTMS WEST. SAT...VFR/MVFR WITH SCT SHWRS/TSTMS ASSOCD WITH COLD FROPA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...RXR AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
249 PM EDT MON SEP 1 2014 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL CONTINUE INTO TUESDAY UNTIL A COLD FRONTAL PASSAGE BRINGS DRIER AND SLIGHTLY COOLER AIR TO CENTRAL PENNSYLVANIA THROUGH MID WEEK. HUMIDITY WILL RETURN TOWARD THE END OF THE WEEK AHEAD OF THE NEXT FRONTAL SYSTEM THAT WILL BRING THE CHANCE OF RAIN FOR THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 18Z...RADAR LOOP INDICATES CONVECTIVE PCPN IS STARTING TO INCREASE IN CVRG OVER THE LAST 30 MINUTES OVER THE SRN 1/3 OF THE CWA WHERE THE RAP SHOWS THE HIGHEST CAPE IN PA. EVEN BETTER INSTABILITY CAN BE FOUND SOUTH OF THE MASON DIXON LINE NEAR THE I95 CORRIDOR WHERE THE FIRST LTG STRIKE OF THE AFTN HAS BEEN DETECTED. HIGHEST POPS /30-40%/ HAVE BEEN PAINTED OVER THE SRN TIER ZONES THRU THE EARLY EVENING HOURS. FURTHER TO THE NORTH...WEAK LG SCALE FORCING COUPLED WITH MARGINAL INSTABILITY /HINDERED BY CLOUD COVER/ AND VERY MOIST/HUMID AIRMASS CONTINUES TO SUPPORT IDEA OF MAINLY ISOLD SHOWERS. MESO MDL GUIDANCE SHOWS EVE STORMS EVENTUALLY DISSIPATING AFTER DARK WITH THE LOSS OF HEATING. UPSTREAM STORMS OVER THE GRT LWR MI/OH VLY SHOULD ALSO EXHIBIT A CONSIDERABLE WEAKENING TREND AS THE EVOLVE EWD AND MAY SURVIVE INTO WRN PA LATE TNGT. MAIN FOCUS WILL SHIFT TO THE WEST TONIGHT AS A WELL-DEFINED COLD FRONT APPROACHES THE AREA FROM THE N/W. HIGHEST POPS /40-50%/ WILL BE OVER THE FAR NW MTNS BASED ON MULTI-MODEL ENSEMBLE CONSENSUS QPF. IT WILL BE MUGGY WITH LOWS 65-70F. LGT WINDS AND HI DEWPOINTS ALONG WITH SOME PARTIAL CLEARING FAVORS SOME LOW CLOUDS/FOG. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... A RELATIVELY LOW AMPLITUDE SHORTWAVE TROUGH WILL SLIDE EWD FROM THE GREAT LAKES/MIDWEST INTO NRN NEW ENGLAND BY THE END OF THE PERIOD. THIS FEATURE WILL DRIVE A WELL-DEFINED COLD FRONT /WITH SHARP MSTR-PW GRADIENT/ SEWD FROM THE LWR LKS/OH VLY ACRS THE N-CNTRL APPALACHIANS. A CONDITIONAL RISK FOR STRONG TO ISOLATED SEVERE STORMS WILL EXIST FROM LATE TUE MORNING THROUGH THE AFTERNOON WITH THE PRIMARY POTNL TSTM HAZARD BEING DAMAGING WINDS. CLOUD COVER FROM UPSTREAM CONVECTION LKLY ONGOING AT 12Z ALONG WITH RESIDUAL OVERNIGHT LOW STRATUS/FOG SHOULD ACT TO LIMIT DESTABILIZATION EARLY TOMORROW. ALTHOUGH 700-500MB LAPSE RATES WILL GENERALLY REMAIN WEAK TO POOR...THE MODELS SHOW A BELT OF STRONGER WESTERLY MID-LVL FLOW AND DEEP LYR SHEAR. THIS SHOULD HELP TO SUPPORT AN INCREASE IN CONVECTIVE PCPN/INTENSITY AS RENEWED DEVELOPMENT OCCURS ALONG OUTFLOWS/DIFFERENTIAL HEATING ZONES BY LATE MORNING INTO THE AFTERNOON...WITH SOME ORGANIZATION INTO LINE SEGMENTS/CLUSTERS. THIS SHOULD YIELD AT LEAST AN ISOLD DMGG WIND THREAT...WARRANTING AN UPGRADE BY SPC TO A CATEGORICAL /SLGT/ RISK DESIGNATION. THIS HAS BEEN REFLECTED IN AN UPDATED HWO. EARLY CLOUDS SHOULD BREAK FOR A WARM AND HUMID DAY WITH FCST HIGHS EXPECTED TO RANGE FROM THE MID 70S OVER THE NW TO NEAR 90 OVER THE LOWER SUSQ VLY. THE SECOND HALF OF THE PERIOD ESPECIALLY AFTER MIDNIGHT SHOULD FEATURE A COOLER/DRYING TREND BEHIND THE FRONT WITH PWS FALLING AOB NORMAL BY 12Z WED. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... HIGH PRESSURE WILL BUILD IN FOR MIDWEEK...BRINGING AT LEAST A COUPLE OF DAYS OF MILD AND LESS HUMID WEATHER. THE HIGH SHOULD MOVE OFF THE EAST COAST LATE IN THE WEEK ALLOWING A RETURN FLOW OF MORE HUMID AIR INTO THE REGION...ALONG WITH THE CHANCE OF SOME MAINLY DIURNAL CONVECTION STARTING FRIDAY. GUIDANCE IS IN PRETTY GOOD AGREEMENT DRAGGING A COLD FRONT THROUGH THE AREA FRIDAY NIGHT AND SATURDAY...ACCOMPANIED BY MORE SHOWERS AND THUNDERSTORMS. THE UPCOMING WEEK WILL BE ONE OF THE RARE EXTENDED PERIODS OF WARMER THAN NORMAL TEMPERATURES WE HAVE SEEN THIS SUMMER. HIGH TEMPERATURES WILL CLIMB TO ALMOST 90 ACROSS THE SOUTH AND EAST ON TUESDAY AHEAD OF THE FRONTAL PASSAGE. THEN THE UPPER RIDGE WILL REBOUND OVER THE EASTERN US FOR THE SECOND HALF OF THE WEEK...KEEPING HIGH TEMPERATURES AT OR SLIGHTLY ABOVE SEASONAL NORMALS FOR EARLY SEPTEMBER. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... 18Z...CIGS/VISBYS HAVE IMPROVED TO VFR OR MVFR AS EXPECTED. HOWEVER DESPITE A GENERAL INCREASE IN SHOWER ACTIVITY THERE IS STILL LOW CONFIDENCE IN POINT TERMINAL IMPACTS. EVOLUTION OF CONVECTIVE ACTIVITY AND COLLOCATION OF BEST INSTABILITY SUGGESTS THE SRN TAFS HAVE THE BEST CHC TO SEE SCT SHOWERS OR A BRIEF TSRA DOWNPOUR. HAVE ADDED SOME 1HR TEMPS THRU 19Z WITH SHOWERS MOVG THRU AOO/UNV. OTHER CONCERN WILL BE CLOUD TRENDS OVERNIGHT WITH MOIST AIRMASS LKLY PROMOTING ANOTHER PERIOD OF LOW CIGS/FOG INTO TUE MORNING. A COLD FRONT MOVG EWD THRU THE MIDWEST WILL ALSO BRING THE CHC FOR SOME SHOWERS TO REACH THE NW 1/4 TO 1/3 OF THE AIRSPACE BY EARLY TUE MORNING. THIS FRONT WILL BE A FOCUS FOR SCT-NMRS SHWRS/TSTMS TUES AFTN-EVE AS IT MOVES SEWD ACRS CENTRAL PA. THE RECENT GUIDANCE SUGGESTS A SLIGHTLY HIGHER PROBABILITY FOR LCL SVR STORMS AND AT LEAST AN ISOLD THREAT FOR DAMAGING TSTM WIND GUSTS. OUTLOOK... WED-THU...PATCHY AM FOG...OTHERWISE VFR. FRI...MAINLY VFR. CHC OF PM TSTMS WEST. SAT...VFR/MVFR WITH SCT SHWRS/TSTMS ASSOCD WITH COLD FROPA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...LA CORTE AVIATION...STEINBUGL
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
108 AM CDT MON SEP 1 2014 .UPDATE... 06Z AVIATION DISCUSSION UPDATED BELOW. && .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT POTENT SHORTWAVE EVIDENT ON WATER VAPOR OVER WYOMING. AHEAD OF THIS WAVE...OMEGA AND UPPER JET MAX HELPING TO MAINTAIN BAND OF RAINFALL THAT HAS TREKKED FROM SOUTH CENTRAL SD TO NORTHEAST SD OVER THE PAST SEVERAL HOURS. HAVE BEEN ADJUSTING POPS FOR THIS BAND OF RAIN AS IT APPEARS IT WILL SURVIVE MOST IF NOT ALL THE WAY ACROSS THE CWA. HRRR PICKING UP ON THIS QUITE NICELY. OVERNIGHT...EXPECTING SCATTERED SHOWERS AND STORMS TO MOVE EAST ACROSS THE STATE BUT WITH MINIMAL SEVERE THREAT DUE TO LACK OF INSTABILITY. ONLY QUESTION IS THE DEGREE OF AREAL COVERAGE OF PRECIP. SOME MODELS GREATER THAN OTHERS...WITH THE HRRR PARTICULARLY DRY AND SORT OF THE OUTLIER. MOST OTHER MODELS HAVE ACTIVITY MOVING ACROSS AT LEAST THE SOUTHERN HALF OF SD TONIGHT. HAVE ADJUSTED POPS ACCORDINGLY AND LINGERED THEM A BIT LONGER THROUGH THE NIGHT AS NSSL WRF STILL SHOWS CONVECTIVE CLUSTERS OVER SOUTHEAST SD AT 09Z TONIGHT. A WEAKER WAVE MOVES ACROSS THE AREA MONDAY...BUT SHOULD STILL PROVIDE FOR A FEW SCATTERED SHOWERS OR STORMS. AREAL COVERAGE DOES NOT APPEAR IT WILL QUITE MATCH UP TO WHATS MOVING INTO WESTERN SD RIGHT NOW...BUT WORTHY OF 20/30 POPS NONETHELESS. AGAIN A LACK OF INSTABILITY TOMORROW SO SEVERE THREAT IS VERY LOW. TUESDAY STILL LOOKS DRY WITH NO NOTABLE SYSTEMS IN THE AREA. 500 MB HEIGHTS RISE SLOWLY THROUGH THE DAY WITH WARM AIR ADVECTION DEVELOPING. HIGHS WILL BUMP UP INTO THE UPPER 70S TO LOW 80S FOR MOST AREAS. .LONG TERM...WEDNESDAY THROUGH SUNDAY THE EARLY PART OF THE PERIOD STARTS OFF SOMEWHAT ACTIVE AS FAIRLY STRONG SYSTEM MOVES ACROSS THE NORTHERN PLAINS. LATEST MODELS ARE IN FAIR AGREEMENT ON AVAILABLE MOISTURE/INSTABILITY BUT DO SUGGEST CAPPING MIGHT FORCE MOST ACTIVITY TO REMAIN NORTH OF THE CWA WEDNESDAY NIGHT INTO THURSDAY AS COLD FRONT MOVES EAST. THUS POPS NO HIGHER THAN CHC NEEDED AT THIS POINT. BEHIND THE FRONT IT LOOKS FAIRLY DRY FROM THURSDAY THROUGH SUNDAY AS HIGH PRESSURE PROVES DOMINANT. TEMPERATURES WILL START OFF ABOVE NORMAL AT THE BEGINNING OF THE PERIOD THEN TREND TOWARD NORMAL OR EVEN BELOW BY THE END OF THE WEEK. && .AVIATION... 06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS A SHORT WAVE TROUGH MOVING EAST OF THE REGION TONIGHT WILL TAKE THE VFR MID LEVEL CLOUDS AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITH IT. THESE MAY AFFECT ABR AND ATY. OTHERWISE...ANOTHER SHORT WAVE TROUGH WILL DROP INTO THE REGION FROM THE NORTHWEST LATE THIS MORNING THROUGH THIS EVENING. WITH STEEP LAPSE RATES...SOME INSTABILITY AND MID LEVEL MOISTURE ...EXPECT MORE MID LEVEL CLOUDS ALONG WITH SCATTERED SHOWERS/STORMS TO DEVELOP AGAIN. SOME OF THESE MAY AFFECT THE TERMINALS. INSERTED SOME VICINITY SHOWERS IN AT ALL LOCATIONS. THESE WILL MOVE ON TO THE EAST MONDAY EVENING. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...MOHR SHORT TERM...TMT LONG TERM...TDK AVIATION...MOHR WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1155 PM CDT SUN AUG 31 2014 .UPDATE...FOR 06Z AVIATION. && .AVIATION...06Z TAF DISCUSSION. SKIES HAVE BEEN CLEARING OVER THE MID-STATE FOR THE LAST COUPLE OF HOURS. THERE IS STILL A POTENTIAL FOR AN IFR CLOUD DECK TO DEVELOP OVER THE NEXT SEVERAL HOURS ACROSS SOUTHERN PORTIONS OF THE STATE AND SLIP NORTHWARD OVER ALL 3 TERMINALS. WHILE THERE ARE NO INDICATIONS OF THIS WANTING TO HAPPEN IN THE CURRENT SATELLITE IMAGERY...SOME OF THE SHORT TERM-HI RES GUIDANCE IS SUGGESTING THIS POSSIBILITY. EVEN IF THIS DOESN`T HAPPEN...WE MAY END UP WITH IFR TO MVFR FOG BY SUNRISE. EITHER WAY...SOME FLIGHT CATEGORY REDUCTION IS POSSIBLE OVERNIGHT. SOUTHERLY WINDS WILL REMAIN LIGHT UNTIL LATE MORNING AND EARLY AFTERNOON ON LABOR DAY WHEN SOUTHWESTERLY BREEZY CONDITIONS DEVELOP. SOME GUSTS OF 16-20 KTS WILL BE POSSIBLE UNTIL 00Z TUESDAY. UNGER && .PREV DISCUSSION... /ISSUED 842 PM CDT SUN AUG 31 2014/ UPDATE... AT 830 PM...RADAR RETURNS WERE MOST DEFINITELY ON A DOWNWARD TREND. SOME SLOW MOVING CELLS DROPPED HEALTHY AMOUNTS OF RAINFALL OVER SE WILSON COUNTY ENOUGH TO WARRANT A FLOOD ADVISORY. DID RECEIVE A CALL MENTIONING LOW LYING AREAS BECOMING INUNDATED IN THAT AREA. HOWEVER...COVERAGE HAS DIMINISHED AND THE MID AND UPPER LEVEL DYNAMICS HAVE MOVED OFF EAST OF THE PLATEAU. AS A RESULT...LOWERED POP CHANCES ACROSS THE AREA UP UNTIL MIDNIGHT AND REMOVED SLGT CHC POPS AFTER MIDNIGHT. IR SATELLITE AND RUC FORECAST SOUNDINGS SHOW MID LEVEL DRYING OVER THE REST OF THE EVENING AND OVERNIGHT...LIKELY RESULTING IN MOSTLY CLEAR SKIES AT LEAST FOR A BIT BEFORE SOME BOUNDARY LAYER MOISTURE ADVECTS NORTHWARD OUT OF NORTHERN ALABAMA DURING THE OVERNIGHT PERIOD. SINCE SFC MOISTURE WILL STAY IN THE UPPER 60S AND LOW 70S AND LOW LEVEL FLOW WILL STAY SOUTHWESTERLY...LEFT PATCHY FOG MENTION IN THE GRIDS THROUGH THE FIRST PART OF THE MORNING. BUT WITH DECENT WIND FIELDS IN THE BOUNDARY LAYER AND AT LEAST SOME CLOUD COVER EXPECTED TOWARDS DAYBREAK...DID NOT SEE REASON TO INCREASE THE FOG COVERAGE TO AREAS OR DENSE WORDING. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 27
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
706 PM CDT TUE SEP 2 2014 .AVIATION... ISOLATED THUNDERSTORMS APPEAR TO HAVE BY-PASSED KLBB WHILE REMAINING FAR WEST OF KCDS THIS EVENING. VFR EXPECTED TO DOMINATE OTHER THAN A RISK FOR AN IFR/MVFR CLOUD LAYER TO DEVELOP JUST AFTER DAYBREAK WEDNESDAY AT KLBB. RMCQUEEN && .PREV DISCUSSION... /ISSUED 531 PM CDT TUE SEP 2 2014/ UPDATE... THUNDERSTORMS HAVE DEVELOPED OVER THE WESTERN AND CENTRAL SOUTH PLAINS...A BIT SOUTH OF PREVIOUS BEST-GUESS...BUT GIVE SHORT TERM SOLUTIONS SOME CREDIT. WE HAVE UPDATED FOR LOW COVERAGE THUNDER THROUGH EARLY THIS EVENING. 1500-2000 JOULES PER KILOGRAM OF CONVECTIVE ENERGY BUT VERY LITTLE SHEAR CONTRIBUTING TO BRIEF HEAVY SHOWERS AND BRIEF MOSTLY WEAK HAIL INDICATIONS AT THIS TIME. ACTIVITY SHOULD TAKE ON BETTER NORTHERLY DRIFT...THOUGH BELIEVE MOST ACTIVITY WILL RELENT BY DARK. RMCQUEEN PREV DISCUSSION... /ISSUED 306 PM CDT TUE SEP 2 2014/ SHORT TERM... FOCUS IN THE SHORT TERM IS ON SMALL CHANCE FOR ISOLATED SHOWERS AND/OR THUNDERSTORMS LATE THIS AFTN AND THIS EVENING. RADAR IS QUIET ATTM BUT SATELLITE SHOWING AN AREA OF CUMULUS DEVELOPMENT TO THE EAST AND SOUTHEAST OF LUBBOCK IN AN AREA WHERE OBJECTIVE ANALYSIS SHOWS ENHANCED INSTABILITY AND WEAKENING INHIBITION. SOME VERY MODEST LOW LEVEL SPEED CONVERGENCE AND MOISTURE ADVECTION IN THIS AREA MAY NOT HELP TOO MUCH BUT CERTAINLY WILL NOT HURT. A WEAK FRONTAL BOUNDARY PULLED UP STATIONARY NEAR A MORTON TO TULIA LINE WITH WEAK CONFLUENCE IN ITS VICINITY BUT WITH SFC DEW POINTS ABOUT 5 DEGREES LOWER THAN IN THE FORMER AREA. WOULD EXPECT THESE TWO AREAS HAVE THE BEST CHANCE OF SEEING CONVECTIVE DEVELOPMENT. 12Z WRF-NAM HIGHLIGHTS THE LATTER WHILE RECENT RUNS OF THE HRRR FEATURES THE FORMER. EITHER WAY WILL LIKELY BE DIFFICULT TO GENERATE ANYTHING OTHER THAN SMALL-SCALE AND ISOLATED SHOWERS WITH AREAL COVERAGE NOT WARRANTING MENTION IN THE ZONE FCST ATTM. WEDNESDAY SHOULD BE EVEN MORE DIFFICULT TO PRODUCE PRECIP WITH STRENGTHENING HIGH PRESSURE OVERHEAD AND LOW LEVEL FLOW BECOMING MORE UNIFORM FROM THE SOUTH. TEMPS TO REMAIN WARMER THAN NORMAL WITH BOTH LOWS AND HIGHS NEAR WARMER MAV GUIDANCE LOOKING MORE LIKELY ATTM. LONG TERM... ONLY MINOR CHANGES TO THE LONG TERM FORECAST FOR THIS ITERATION...AS A MUTED COOLING TREND WILL BE FOLLOWED BY A POTENTIALLY WET WEEKEND FOR PARTS OF THE REGION. BY WEDNESDAY EVENING...A MOSTLY ZONAL UPPER FLOW REGIME WILL BE IN PLACE ACROSS THE CONUS...WITH AN ELONGATED UPPER RIDGE IN PLACE ACROSS MOST OF THE SOUTH...INCLUDING WEST TEXAS. WHILE THIS WILL CONTINUE TO ENSURE MOSTLY DRY CONDITIONS THROUGH THE END OF THE WORK WEEK...GRADUALLY DROPPING 1000-500 MB THICKNESSES WILL ALLOW TEMPERATURES TO INCREMENTALLY FALL BACK TO A MORE REASONABLE UPPER 80S ON THE SOUTH PLAINS TO MID 90S ON THE ROLLING PLAINS. BY LATE IN THE WEEK AND THROUGH THE WEEKEND...A BROAD UPPER TROUGH WILL PUSH EASTWARD ACROSS THE NORTHERN CONUS...SENDING A MODEST COLD FRONT SOUTHWARD THROUGH THE CENTRAL PLAINS AND AT LEAST THE TEXAS PANHANDLE. MEANWHILE DEEPER MONSOONAL MOISTURE...POSSIBLY WITH A CONNECTION TO REMNANTS OF TROPICAL STORM DOLLY...WILL BE DRAWN NORTHWARD INTO THE SOUTHWEST AND EVENTUALLY EASTWARD AS IT GETS CAUGHT IN THE WESTERLY UPPER FLOW ASSOCIATED WITH THE PREVIOUSLY MENTIONED TROUGH. ALL OF THIS IS EXPECTED TO RESULT IN INCREASING RAIN CHANCES BEGINNING AS EARLY AS LATE FRIDAY...AND POSSIBLY LASTING THROUGH LATE SUNDAY DEPENDING ON A FEW FACTORS. THE MOST PROMINENT OF THESE FACTORS SEEMS TO BE THE TIMING AND STRENGTH OF THE APPROACHING COLD FRONT...AS THE GFS AND ECMWF REMAIN ABOUT 24 HOURS APART IN THIS REGARD. THE GFS INDICATES A SLOWER...WEAKER FRONT REACHING THE NORTHERN BORDER OF THE CWA LATE SATURDAY AFTERNOON AND WASHING OUT ACROSS THE CWA SUNDAY. MEANWHILE...THE ECMWF SOLUTION BRINGS THIS FRONT INTO THE AREA AS EARLY AS LATE FRIDAY...AND PUSHES THE BOUNDARY WELL THROUGH THE CWA BY LATE SATURDAY. THE LATTER SOLUTION NOT SURPRISINGLY DEVELOPS THE HEAVIEST PRECIPITATION DURING THE LATE FRIDAY THROUGH SATURDAY TIME FRAME...WHILE THE GFS SEEMS TO BE FOCUSING ON THE LATE SATURDAY THROUGH LATE SUNDAY TIME FRAME. GIVEN THAT THE BOUNDARY WILL BE WELL REMOVED FROM ITS PARENT TROUGH BY THE TIME IT REACHES THIS LATITUDE...WE WILL CONTINUE TO SIDE WITH THE SLOWER GFS SOLUTION AND HIGHLIGHT LATE SATURDAY WITH THE HIGHEST POPS. LIKEWISE...LOW END POPS WERE ALSO EXTENDED THROUGH SUNDAY EVENING GIVEN THAT IN THIS SLOWER SCENARIO REMNANTS OF THIS BOUNDARY AND AMPLE MOISTURE WOULD LIKELY LINGER THROUGH THIS PERIOD. HOWEVER...UNCERTAINTIES REGARDING FRONTAL TIMING AND STRENGTH ARE COMPOUNDED FURTHER ON SUNDAY WITH THE POSSIBILITY OF LINGERING NOCTURNAL CONVECTION AND STABILIZING OUTFLOWS. BY MONDAY...THE UPPER RIDGE IS EXPECTED TO SLIGHTLY AMPLIFY ACROSS THE SOUTHERN PLAINS WHILE THE COLUMN DRIES CONSIDERABLY. THIS SHOULD TAPER OFF PRECIPITATION CHANCES UNTIL LATER IN THE WEEK WHEN ANOTHER POSSIBLY STRONGER COLD FRONT MOVES THROUGH THE REGION. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 61 92 62 90 62 / 10 0 10 10 10 TULIA 68 93 66 91 66 / 20 0 10 0 10 PLAINVIEW 68 93 66 90 66 / 20 0 0 0 10 LEVELLAND 66 92 66 90 67 / 20 0 10 10 0 LUBBOCK 72 93 68 92 67 / 20 0 0 10 0 DENVER CITY 66 91 66 89 66 / 20 0 10 10 10 BROWNFIELD 68 93 67 90 67 / 20 0 0 10 0 CHILDRESS 75 97 75 96 72 / 10 0 0 0 0 SPUR 73 97 72 94 71 / 10 0 0 10 10 ASPERMONT 76 99 74 96 73 / 0 0 0 10 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/05
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AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
141 AM EDT MON SEP 1 2014 .SYNOPSIS... THE REGION WILL STAY BETWEEN A LARGE HIGH PRESSURE SYSTEM OVER THE SOUTHEAST UNITED STATES AND A COMPLEX LOW PRESSURE SYSTEM CROSSING THE GREAT LAKES. DISTURBANCES PASSING BETWEEN THESE TWO FEATURES WILL COMBINE WITH HEAT AND HUMIDITY TO RESULT IN PERIODIC CHANCES OF SHOWERS AND STORMS INTO EARLY WEEK. A COLD FRONT FINALLY ARRIVES FROM THE NORTH WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 102 AM EDT MONDAY... MADE SOME MINOR ADJUSTMENTS IN POPS AND TEMPERATURES FOR THIS MORNING. SHAPED POPS THIS MORNING TOWARDS A BLEND OF RAP AND HRRR. MORE CHANGES LATER THIS MORNING. AS OF 920 PM EDT SUNDAY... MAIN AXIS OF MOISTURE CONVERGENCE LIES FROM MD-CENTRAL WV. MAIN UPPER IMPULSE THAT WAS OVER TN EARLIER HAS WEAKENED AS HAVE THE SHOWERS UPSTREAM. OVERNIGHT NOT REALLY SEEING MUCH AS AIRMASS STABILIZES. WILL KEEP THE HIGHER POPS OVER THE WV MTNS INTO FAR SW VA...AS ANOTHER WEAK IMPULSE EDGES CLOSER TO THE MTNS BY DAWN. OTHERWISE EXPECT MID DECK OF CLOUDS TO REMAIN IN THE WESTERN HALF OF THE CWA WHILE THE EAST CLEARS SOME TOWARD MORNING. OVERALL FOG THREAT IS PATCHY BUT COULD GET DENSE OUT EAST IF IT CLEARS OUT ENOUGH. NO OTHER MAJOR CHANGES TO THE FORECAST THROUGH DAWN. PREVIOUS VALID DISCUSSION... SHORTWAVES WILL BE EXITING BY EARLY MONDAY LEAVING THE REGION IN DECENT WEST/SW FLOW ALOFT BUT WITHOUT MUCH FORCING WELL IN ADVANCE OF THE NEXT UPSTREAM 5H TROF/COLD FRONT TO THE NW. FORECAST SOUNDINGS SHOW QUITE A DEEP WESTERLY FLOW WHICH RESULTS IN DRYING ALOFT/LOWERING PWATS ESPCLY WEST MONDAY AFTERNOON AND A LEE TROUGH ACROSS THE PIEDMONT. MOST GUIDANCE SOLUTIONS SHOW A LACK OF MUCH CONVECTION IN THIS REGIME WITH ANY FOCUS PROVIDED BY OROGRAPHICS DUE TO WESTERLY CONVERGENCE AND PERHAPS LATE DAY LOW LEVEL BACKING SE. THUS WILL LEAVE IN SOME LOW POPS MAINLY WEST AS APPEARS A SUBTLE WAVE ALOFT COULD SNEAK THROUGH AROUND THE TIME OF MAX HEATING. OTRW EXPECT WEAK LAPSES...LACK OF DEEP INSTABILITY AND EASTERN DOWNSLOPE TO LIMIT OVERALL COVERAGE WITH MUCH OF THE DAY LIKELY DRY AFTER EARLY MID DECK/FOG ERODE. COULD BE ONE OF THE WARMEST DAYS SEEN IN A WHILE WITH 85H TEMPS PUSHING +21C OVER DECENT DOWNSLOPE AND UNDER AMPLE AFTERNOON SUN. THIS WOULD SUPPORT SOME MID 90S PIEDMONT...WITH UPPER 80S/LOW 90S BLUE RIDGE... AND LOW/MID 80S WESTERN ELEVATIONS IF CAN GET A TEMP JUMP AFTER A WARM START IN THE MORNING. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AS OF 230 PM EDT SUNDAY... WITH WEAK HIGH PRESSURE BUILDING IN FROM THE SOUTH...EXPECT TO HEAD INTO LATE MONDAY NIGHT WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. AS SUCH...WOULD NOT BE SURPRISED TO SEE PATCHY FOG DEVELOP IN SOME OF THE MOUNTAIN VALLEYS EARLY MORNING...WHICH WILL BURN OFF QUICKLY SHORTLY AFTER 9 AM. DURING TUESDAY AFTERNOON...SHOWER AND THUNDERSTORM ACTIVITY WILL INCREASE AS AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT APPROACH FROM THE WEST. ACTIVITY WILL START OFF ACROSS THE MOUNTAINS...SPOTTY AT FIRST DUE TO THE WESTERLY DOWNSLOPE FLOW...AND THEN WILL SPREAD EAST ACROSS THE PIEDMONT DURING THE EVENING AS THE UPPER LEVEL ENERGY SHIFTS EAST. LIGHT WINDS AND WARM TEMPERATURES ALOFT WILL LIMIT INSTABILITY...AND BELIEVE STRONG THUNDERSTORMS WILL BE ISOLATED AND SHORT LIVED. SHOWER AND THUNDERSTORM ACTIVITY WILL THEN DIMINISH THROUGH THE NIGHT WITH THE LOSS OF HEATING. BY WEDNESDAY MORNING...WILL HAVE A WEAK BOUNDARY SITUATED ACROSS OUR AREA...WHICH WILL EXHIBIT LITTLE MORE THAN A SHIFT IN WIND DIRECTION FROM ONE SIDE TO THE OTHER AS THE TRULY COOLER AND DRIER AIR WILL REMAIN WELL NORTH OF OUR AREA. REGARDLESS...THE LOW LEVEL CONVERGENCE ALONG THE BOUNDARY WILL BE ENOUGH TO TRIGGER ANOTHER ROUND OF SPOTTY SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON AND EVENING. BETTER CHANCES FOR RAINFALL WILL BE FOUND SOUTH OF HIGHWAY 460. TEMPERATURES HEADING INTO THE MIDDLE OF THE WEEK WILL BE WARMER THAN NORMAL THANKS TO UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES. LOOK FOR HIGHS TO RANGE FROM THE LOW/MID 80S ACROSS THE MOUNTAINS... TO THE LOW/MID 90S ACROSS THE SOUTHSIDE. OVERNIGHT LOWS WILL RANGE FROM THE MID 60S WEST TO THE LOW 70S EAST. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 345 PM SUNDAY... A WEAK BOUNDARY WILL REMAIN SITUATED ACROSS THE AREA ON THURSDAY... PROVIDING THE LOW LEVEL FOCUS FOR SHOWERS AND THUNDERSTORMS... MAINLY SOUTH OF HIGHWAY 460. ACTIVITY IS EXPECTED TO REMAIN WIDELY SCATTERED DUE TO THE UPPER LEVEL RIDGE ACROSS THE SOUTHEAST STATES BUILDING NORTH...HELPING TO LIMIT INSTABILITY. HIGH PRESSURE WILL PASS ACROSS NEW ENGLAND...ALLOWING WINDS TO SHIFT EASTERLY THROUGH THE DAY...AND THEN SOUTHEASTERLY DURING THE EVENING. AN APPROACHING UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE REGION ON FRIDAY AND SATURDAY. THE COLD FRONT WILL MOVE ACROSS OUR AREA SATURDAY NIGHT...USHERING IN COOLER AND DRIER CANADIAN HIGH PRESSURE. TROPICAL AIR WILL REMAIN ACROSS THE AREA THROUGH THE END OF THE WEEK. AS SUCH...EXPECT WARM AND MUGGY CONDITIONS...WITH TEMPERATURES HOLDING SLIGHTLY ABOVE NORMAL. COOLER TEMPERATURES WILL ARRIVE WITH THE COLD FRONT AT THE END OF THE WEEK. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 127 AM EDT MONDAY... A SHORTWAVE WILL LIFT NORTHEAST THIS MORNING ACROSS THE REGION. A FEW SHOWERS WILL MOVE EAST ACROSS THE REGION THIS MORNING. THE BEST CHANCE OF A SHOWER WILL OCCUR AT BLF AND LWB. IN THE WAKE OF THE SHORTWAVE...THE OVERALL THREAT OF SHOWERS WILL FADE WITH A SCT/BKN MID DECK LINGERING. PATCHY FOG MAY DEVELOP THIS MORNING...BUT THE MID DECK SHOULD LIMIT HOW FAR DOWN VSBYS DROP. WILL KEEP MOST TAF SITES NO WORSE THAN MVFR THIS MORNING WITH LWB DROPPING OCCASIONALLY TO IFR AFTER 10Z. AHEAD OF THE UPSTREAM COLD FRONT...DEEP WESTERLY FLOW COMBINED WITH LACK OF FOCUS AND DECENT MIXING SHOULD INHIBIT MUCH CONVECTION TODAY ESPECIALLY IF EARLY MID DECK PERSISTS. THIS SUPPORTS GOOD FLYING CONDITIONS FOR MUCH OF LABOR DAY AFTER EARLY LOW CLOUDS/FOG FADE WITH ONLY ISOLATED CONVECTION LIKELY. MEDIUM CONFIDENCE ON CEILINGS...VISIBILITIES AND WINDS DURING THE TAF PERIOD. EXTENDED DISCUSSION... UPPER TROUGH AND ITS ASSOCIATED COLD FRONT WILL APPROACH FROM THE NORTHWEST TUESDAY WITH SIMILAR ISOLATED SHOWERS/STORMS EXPECTED DURING THE DAY AHEAD OF THE BOUNDARY. FRONT SETTLES CLOSER TUESDAY NIGHT INTO WEDNESDAY...WHEN BETTER COVERAGE OF SHRA/TSRA IS EXPECTED...AND THEN ACROSS THE SOUTH THURSDAY WHERE THE BOUNDARY STALLS. HOWEVER LOW CONFIDENCE ON THE TIMING AND SOUTHWARD POSITION OF THE BOUNDARY AT THIS POINT. THUS APPEARS MAINLY VFR ON TUESDAY...WITH PERIODS OF MVFR WEDNESDAY-THURSDAY IN MORE ORGANIZED MAINLY AFTERNOON/EVENING CONVECTION...AND MVFR/IFR UNDER EARLY MORNING FOG IN THE VALLEYS AND WHERE EARLIER HEAVY RAIN OCCURRED. FRONT WASHES OUT TO THE SOUTH OF THE AREA FRIDAY WITH MORE DIURNAL NATURE SHOWERS AND STORMS...OTRW VFR. && .EQUIPMENT... AS OF 730 AM EDT FRIDAY ... THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL AIRPORT...WILL BE OUT OF SERVICE UNTIL FURTHER NOTICE. A PART HAS BEEN BACK-ORDERED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/JH NEAR TERM...JH/KK/WP SHORT TERM...NF LONG TERM...NF AVIATION...JH/KK/WP EQUIPMENT...AMS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
102 AM EDT MON SEP 1 2014 .SYNOPSIS... THE REGION WILL STAY BETWEEN A LARGE HIGH PRESSURE SYSTEM OVER THE SOUTHEAST UNITED STATES AND A COMPLEX LOW PRESSURE SYSTEM CROSSING THE GREAT LAKES. DISTURBANCES PASSING BETWEEN THESE TWO FEATURES WILL COMBINE WITH HEAT AND HUMIDITY TO RESULT IN PERIODIC CHANCES OF SHOWERS AND STORMS INTO EARLY WEEK. A COLD FRONT FINALLY ARRIVES FROM THE NORTH WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 102 AM EDT MONDAY... MADE SOME MINOR ADJUSTMENTS IN POPS AND TEMPERATURES FOR THIS MORNING. SHAPED POPS THIS MORNING TOWARDS A BLEND OF RAP AND HRRR. MORE CHANGES LATER THIS MORNING. AS OF 920 PM EDT SUNDAY... MAIN AXIS OF MOISTURE CONVERGENCE LIES FROM MD-CENTRAL WV. MAIN UPPER IMPULSE THAT WAS OVER TN EARLIER HAS WEAKENED AS HAVE THE SHOWERS UPSTREAM. OVERNIGHT NOT REALLY SEEING MUCH AS AIRMASS STABILIZES. WILL KEEP THE HIGHER POPS OVER THE WV MTNS INTO FAR SW VA...AS ANOTHER WEAK IMPULSE EDGES CLOSER TO THE MTNS BY DAWN. OTHERWISE EXPECT MID DECK OF CLOUDS TO REMAIN IN THE WESTERN HALF OF THE CWA WHILE THE EAST CLEARS SOME TOWARD MORNING. OVERALL FOG THREAT IS PATCHY BUT COULD GET DENSE OUT EAST IF IT CLEARS OUT ENOUGH. NO OTHER MAJOR CHANGES TO THE FORECAST THROUGH DAWN. PREVIOUS VALID DISCUSSION... SHORTWAVES WILL BE EXITING BY EARLY MONDAY LEAVING THE REGION IN DECENT WEST/SW FLOW ALOFT BUT WITHOUT MUCH FORCING WELL IN ADVANCE OF THE NEXT UPSTREAM 5H TROF/COLD FRONT TO THE NW. FORECAST SOUNDINGS SHOW QUITE A DEEP WESTERLY FLOW WHICH RESULTS IN DRYING ALOFT/LOWERING PWATS ESPCLY WEST MONDAY AFTERNOON AND A LEE TROUGH ACROSS THE PIEDMONT. MOST GUIDANCE SOLUTIONS SHOW A LACK OF MUCH CONVECTION IN THIS REGIME WITH ANY FOCUS PROVIDED BY OROGRAPHICS DUE TO WESTERLY CONVERGENCE AND PERHAPS LATE DAY LOW LEVEL BACKING SE. THUS WILL LEAVE IN SOME LOW POPS MAINLY WEST AS APPEARS A SUBTLE WAVE ALOFT COULD SNEAK THROUGH AROUND THE TIME OF MAX HEATING. OTRW EXPECT WEAK LAPSES...LACK OF DEEP INSTABILITY AND EASTERN DOWNSLOPE TO LIMIT OVERALL COVERAGE WITH MUCH OF THE DAY LIKELY DRY AFTER EARLY MID DECK/FOG ERODE. COULD BE ONE OF THE WARMEST DAYS SEEN IN A WHILE WITH 85H TEMPS PUSHING +21C OVER DECENT DOWNSLOPE AND UNDER AMPLE AFTERNOON SUN. THIS WOULD SUPPORT SOME MID 90S PIEDMONT...WITH UPPER 80S/LOW 90S BLUE RIDGE... AND LOW/MID 80S WESTERN ELEVATIONS IF CAN GET A TEMP JUMP AFTER A WARM START IN THE MORNING. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AS OF 230 PM EDT SUNDAY... WITH WEAK HIGH PRESSURE BUILDING IN FROM THE SOUTH...EXPECT TO HEAD INTO LATE MONDAY NIGHT WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. AS SUCH...WOULD NOT BE SURPRISED TO SEE PATCHY FOG DEVELOP IN SOME OF THE MOUNTAIN VALLEYS EARLY MORNING...WHICH WILL BURN OFF QUICKLY SHORTLY AFTER 9 AM. DURING TUESDAY AFTERNOON...SHOWER AND THUNDERSTORM ACTIVITY WILL INCREASE AS AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT APPROACH FROM THE WEST. ACTIVITY WILL START OFF ACROSS THE MOUNTAINS...SPOTTY AT FIRST DUE TO THE WESTERLY DOWNSLOPE FLOW...AND THEN WILL SPREAD EAST ACROSS THE PIEDMONT DURING THE EVENING AS THE UPPER LEVEL ENERGY SHIFTS EAST. LIGHT WINDS AND WARM TEMPERATURES ALOFT WILL LIMIT INSTABILITY...AND BELIEVE STRONG THUNDERSTORMS WILL BE ISOLATED AND SHORT LIVED. SHOWER AND THUNDERSTORM ACTIVITY WILL THEN DIMINISH THROUGH THE NIGHT WITH THE LOSS OF HEATING. BY WEDNESDAY MORNING...WILL HAVE A WEAK BOUNDARY SITUATED ACROSS OUR AREA...WHICH WILL EXHIBIT LITTLE MORE THAN A SHIFT IN WIND DIRECTION FROM ONE SIDE TO THE OTHER AS THE TRULY COOLER AND DRIER AIR WILL REMAIN WELL NORTH OF OUR AREA. REGARDLESS...THE LOW LEVEL CONVERGENCE ALONG THE BOUNDARY WILL BE ENOUGH TO TRIGGER ANOTHER ROUND OF SPOTTY SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON AND EVENING. BETTER CHANCES FOR RAINFALL WILL BE FOUND SOUTH OF HIGHWAY 460. TEMPERATURES HEADING INTO THE MIDDLE OF THE WEEK WILL BE WARMER THAN NORMAL THANKS TO UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES. LOOK FOR HIGHS TO RANGE FROM THE LOW/MID 80S ACROSS THE MOUNTAINS... TO THE LOW/MID 90S ACROSS THE SOUTHSIDE. OVERNIGHT LOWS WILL RANGE FROM THE MID 60S WEST TO THE LOW 70S EAST. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 345 PM SUNDAY... A WEAK BOUNDARY WILL REMAIN SITUATED ACROSS THE AREA ON THURSDAY... PROVIDING THE LOW LEVEL FOCUS FOR SHOWERS AND THUNDERSTORMS... MAINLY SOUTH OF HIGHWAY 460. ACTIVITY IS EXPECTED TO REMAIN WIDELY SCATTERED DUE TO THE UPPER LEVEL RIDGE ACROSS THE SOUTHEAST STATES BUILDING NORTH...HELPING TO LIMIT INSTABILITY. HIGH PRESSURE WILL PASS ACROSS NEW ENGLAND...ALLOWING WINDS TO SHIFT EASTERLY THROUGH THE DAY...AND THEN SOUTHEASTERLY DURING THE EVENING. AN APPROACHING UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE REGION ON FRIDAY AND SATURDAY. THE COLD FRONT WILL MOVE ACROSS OUR AREA SATURDAY NIGHT...USHERING IN COOLER AND DRIER CANADIAN HIGH PRESSURE. TROPICAL AIR WILL REMAIN ACROSS THE AREA THROUGH THE END OF THE WEEK. AS SUCH...EXPECT WARM AND MUGGY CONDITIONS...WITH TEMPERATURES HOLDING SLIGHTLY ABOVE NORMAL. COOLER TEMPERATURES WILL ARRIVE WITH THE COLD FRONT AT THE END OF THE WEEK. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 725 PM EDT SUNDAY... TOOK SHOWERS OUT OF THE LWB TAF THIS EVENING. STILL CANNOT RULE OUT A SHOWER INVOF BLF/LWB OVERNIGHT BUT THE CHANCES ARE LIMITED. OTHERWISE...OVERNIGHT THE OVERALL THREAT OF SHOWERS WILL FADE WITH A SCT/BKN MID DECK LINGERING. FOG CHANCES ARE GOOD BUT THE MID DECK SHOULD LIMIT HOW FAR DOWN VSBYS DROP. WILL KEEP MOST TAF SITES NO WORSE THAN MVFR OVERNIGHT WITH LWB DROPPING OCCASIONALLY TO IFR AFTER 10Z. LAST MID LEVEL WAVE WILL PASS TO THE NW BY EARLY MONDAY LEAVING THE AREA IN BETWEEN THIS FEATURE AND THE NEXT UPSTREAM COLD FRONT. DEEP WESTERLY FLOW COMBINED WITH LACK OF FOCUS AND DECENT MIXING SHOULD INHIBIT MUCH CONVECTION DURING MONDAY ESPCLY IF EARLY MID DECK PERSISTS. THIS SUPPORTS GOOD FLYING CONDITIONS FOR MUCH OF MONDAY AFTER EARLY LOW CLOUDS/FOG FADE WITH ONLY ISOLATED CONVECTION LIKELY. EXTENDED DISCUSSION... UPPER TROUGH AND ITS ASSOCIATED COLD FRONT WILL APPROACH FROM THE NORTHWEST TUESDAY WITH SIMILAR ISOLATED SHOWERS/STORMS EXPECTED DURING THE DAY AHEAD OF THE BOUNDARY. FRONT SETTLES CLOSER TUESDAY NIGHT INTO WEDNESDAY...WHEN BETTER COVERAGE OF SHRA/TSRA IS EXPECTED...AND THEN ACROSS THE SOUTH THURSDAY WHERE THE BOUNDARY STALLS. HOWEVER LOW CONFIDENCE ON THE TIMING AND SOUTHWARD POSITION OF THE BOUNDARY AT THIS POINT. THUS APPEARS MAINLY VFR ON TUESDAY...WITH PERIODS OF MVFR WEDNESDAY-THURSDAY IN MORE ORGANIZED MAINLY AFTERNOON/EVENING CONVECTION...AND MVFR/IFR UNDER EARLY MORNING FOG IN THE VALLEYS AND WHERE EARLIER HEAVY RAIN OCCURRED. FRONT WASHES OUT TO THE SOUTH OF THE AREA FRIDAY WITH MORE DIURNAL NATURE SHOWERS AND STORMS...OTRW VFR. && .EQUIPMENT... AS OF 730 AM EDT FRIDAY ... THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL AIRPORT...WILL BE OUT OF SERVICE UNTIL FURTHER NOTICE. A PART HAS BEEN BACK-ORDERED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/JH NEAR TERM...JH/KK/WP SHORT TERM...NF LONG TERM...NF AVIATION...AMS/JH/WP EQUIPMENT...AMS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1239 PM CDT MON SEP 1 2014 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 308 AM CDT MON SEP 1 2014 WATER VAPOR SATELLITE LOOP COUPLED WITH RAP ANALYSIS SHOWS VIGOROUS MID-LEVEL TROUGH ROTATING THROUGH THE PLAINS TOWARD THE UPPER MISSISSIPPI RIVER VALLEY. AT THE SURFACE 999MB LOWS WAS OVER WESTERN ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD THROUGH MN/NW IA/CENTRAL NEB. RADAR WAS LIT UP WITH SHOWERS/THUNDERSTORMS ACROSS EASTERN MN INTO THE FORECAST AREA AHEAD OF THE MID-LEVEL WAVE AND SURFACE COLD FRONT. OTHERWISE...TEMPERATURES ACROSS THE AREA EARLY THIS MORNING WERE IN THE 60S. LOOK FOR THE SURFACE COLD FRONT AND ASSOCIATED CONVECTION TO CONTINUE PUSHING EAST ACROSS THE AREA THIS MORNING WITH THE BULK OF THE RAIN EXITING EAST BY LATE MORNING. KEPT LINGERING AND DIMINISHING CHANCES GOING HOWEVER INTO THE AFTERNOON AS THE MID- LEVEL TROUGH/COLD AIR ALOFT POSSIBLY POPPING A FEW INSTABILITY SHOWERS AND THUNDERSTORMS. NOT EXPECTING ANY SEVERE THREAT AS BEST CAPE AND WIND SHEAR SHIFT EAST/SOUTHEAST OF THE AREA. FOR TONIGHT...WILL SEE ANOTHER WEAK MID-LEVEL WAVE ROTATE TOWARD THE AREA FROM THE NORTHERN PLAINS. NAM SHOWING A DECENT SHOT OF 700- 300MB PVA MOVING IN MAINLY WEST OF THE MISSISSIPPI RIVER AFTER MIDNIGHT WITH BUFKIT SHOWING INSTABILITY/MOISTURE MAINLY CONFINED ABOVE 800MB. KEPT A SMALL-END CHANCE OF SHOWERS/ISOLATED WEST OF THE MISSISSIPPI AFTER MIDNIGHT BASED ON THIS SIGNAL. OVERNIGHT LOWS ARE EXPECTED TO FALL INTO THE 50S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 308 AM CDT MON SEP 1 2014 A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO TUESDAY MAINLY NORTH OF I-94 AS THE WEAK MID-LEVEL TROUGH ROTATES ACROSS THE FORECAST AREA. PLAN ON HIGHS RANGING FROM THE MIDDLE 70S ACROSS NORTH CENTRAL WI...TO THE UPPER 70S/LOWER 80S ELSEWHERE. SURFACE CYCLOGENESIS OVER THE NORTHERN PLAINS WILL PUSH A WARM FRONT TOWARD THE AREA WEDNESDAY/WEDNESDAY NIGHT. ALL MODELS SHOW INCREASING 850MB MOISTURE TRANSPORT/WARM AIR ADVECTION NOSING INTO THE AREA WITH THE FRONT FOR INCREASING COVERAGE OF THUNDERSTORMS. PRECIPITABLE WATER VALUES PUSHING 1.9 INCHES BY THURSDAY MORNING WITH WARM CLOUD DEPTH LAYERS INCREASING INTO THE 4-4.5KM RANGE. BASED ON THIS SIGNAL...WILL HAVE TO WATCH FOR A HEAVY RAINFALL POTENTIAL ALONG WITH OTHER SEVERE THREATS AS WELL AS CAPE AND BULK SHEAR INCREASE ALONG THE WARM FRONT. AT THIS POINT...MODELS SHOWING HIGHER SEVERE POTENTIAL STAYING WEST OF THE MISSISSIPPI RIVER IN MORE FAVORABLE CAPE/SHEAR ENVIRONMENT. WILL HAVE TO KEEP A CLOSE ON THIS OVER THE NEXT COUPLE DAYS. LOOK FOR HIGHS ON WEDNESDAY TO TOP OFF IN THE UPPER 70S TO MIDDLE 80S WITH DEW POINTS CREEPING UP INTO THE 65- 70 DEGREE RANGE. THUNDERSTORM CHANCES CONTINUE THURSDAY INTO THURSDAY NIGHT AS THE LOW PULLS NORTHEAST INTO ONTARIO CANADA...PUSHING A COLD FRONT THROUGH THE AREA. THURSDAY WILL HAVE TO BE WATCHED CLOSELY AS WELL FOR SEVERE POTENTIAL AS THE GFS IS SHOWING 0-6KM BULK SHEAR OF 30- 50KT COUPLED WITH MUCAPE POOL OF 2500-4500J/KG. HIGHS ON THURSDAY AHEAD OF THE COLD FRONT ARE EXPECTED TO TOP OFF WELL INTO THE 80S WITH DEW POINTS IN THE 70-75 DEGREE RANGE. DRIER/COOLER AIR FILTERS INTO THE AREA FRIDAY AND INTO THE WEEKEND AS CANADIAN HIGH PRESSURE BUILD INTO THE REGION. PLAN ON TEMPERATURES BY THIS WEEKEND TO FEEL A BIT MORE LIKE FALL WITH HIGHS IN THE 60S/LOWER 70S AND LOWS IN THE 50S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1239 PM CDT MON SEP 1 2014 MAIN AVIATION FORECAST CONCERNS IS FOG POTENTIAL IN THE MISSISSIPPI RIVER VALLEY TONIGHT. LATEST KARX RADAR INDICATES LAST LINE OF SHOWERS ALONG SURFACE COLD FRONT EXTENDING FROM WESTERN WISCONSIN INTO NORTHEAST IOWA PER LATEST 17Z SURFACE ANALYSIS. LATEST 17Z METARS ARE INDICATING CEILING HEIGHTS RISING ABOVE MVFR CONDITIONS AND BECOMING VFR CONDITIONS AT TAF SITES THIS AFTERNOON. WEAK SURFACE RIDGE BUILDS INTO NORTHERN IOWA BEHIND COLD FRONT AND ALLOWS SKIES TO CLEAR WEST TO EAST ACROSS THE AREA THIS AFTERNOON INTO THIS EVENING. THE 02.12Z NAM BUFKIT SOUNDING SHOWS INVERSION DEVELOPING AT LSE TAF SITE AND WINDS BECOME LIGHT WITHIN THE LOWEST 500 FEET...HOWEVER BUFKIT SOUNDING SHOW 15 KNOTS JUST ABOVE 500 FEET PLUS A WEAK IMPULSE PRODUCES A MID LEVEL CLOUD DECK OVER THE REGION. THIS WOULD INHIBIT ANY FOG DEVELOPMENT IN THE MISSISSIPPI RIVER VALLEY AND AT LSE TAF SITE. AT THIS TIME...DID NOT INTRODUCE ANY FOG AT LSE TAF SITE AND LATER SHIFTS WILL HAVE TO MONITOR IF SKIES REMAIN CLEAR THROUGH THE NIGHT TIME HOURS. VFR CONDITIONS WILL PREVAIL AT RST TAF SITE THROUGH MUCH OF THE PERIOD. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1050 AM CDT MON SEP 1 2014 .AVIATION/18Z TAFS/...LOW PRESSURE LIFTING NORTHEAST FROM LAKE SUPERIOR WITH TRAILING COLD FRONT INTO NW WI THROUGH CNTRL IA. AIRMASS QUITE STABLE ATTM AHEAD OF THIS FRONT WITH JUST A COUPLE BATCHES OF SHRA. CLOUD COVER IS EXTENSIVE AND PRIMARY SHORTWAVE/SPEED MAX LIFTING NORTHEAST. EXTENSIVE CLOUD COVER UPSTREAM LIKELY TO KEEP INSTABILITY FROM GETTING OUT OF HAND....THOUGH SOME HERE AND THERE. SO WHILE FRONT IS YET TO WORK THROUGH...SVR CONVECTIVE DEVELOPMENT NOT LIKELY. MESO MODELS CONTINUE TO PULL BACK ON STORM STRENGTH THIS AFTN/EVE...SO AGREE WITH SPC/S REMOVAL OF SLGT RISK FROM SRN WI. EXPECT MVFR CIGS TO LINGER INTO THE AFTERNOON WITH THE VERY MOIST LOW LEVELS AHEAD OF THE COLD FRONT. SOME IMPROVEMENT OF THESE CIGS INTO THIS EVENING ONCE SFC COLD FRONT WORKS THROUGH AND DRIER NW WINDS KICK IN. WEAK HIGH BUILDS IN TNGT WITH SFC TROUGH POSSIBLY GENERATING A FEW SHRA TUE AFTN. PC && .PREV DISCUSSION... /ISSUED 355 AM CDT MON SEP 1 2014/ TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM. AREA OF RAIN SHOWERS AND A FEW THUNDERSTORMS OVER SOUTHWEST WISCONSIN...INTO FAR EASTERN IOWA AND FAR NORTHWEST ILLINOIS...HAS BEEN SLOWLY WEAKENING OVER THE PAST FEW HOURS. THIS WAS BEING DRIVEN BY 500 MB VORTICITY MAXIMUM MOVING INTO THE AREA...UPPER DIVERGENCE WITH RIGHT REAR QUADRANT OF 250 MB JET STREAK...ALONG WITH 850 MB LOW LEVEL JET. SPC MESOANALYSIS PAGE SHOWING A GOOD AMOUNT OF CONVECTIVE INHIBITION OVER THE AREA...WHICH MAY BE HELPING WEAKEN CONVECTION. STILL...THE ABOVE MAIN FEATURES SHOULD CONTINUE TO BRING SOME SHOWERS ACROSS THE AREA THROUGH THE MIDDLE MORNING HOURS. THIS IS SUPPORTED BY THE HRRR AND OTHER MESOSCALE MODELS...THOUGH THEY AREA SOMEWHAT OVERDONE WITH CURRENT PRECIPITATION TRENDS. THUS...WILL CONTINUE HIGH POPS THROUGH THE MIDDLE MORNING HOURS FOR SHOWERS AND ISOLATED STORMS. MAIN ISSUE WILL BE CONVECTIVE TRENDS THIS AFTERNOON AND EVENING WITH PASSING COLD FRONT AND SEVERE WEATHER POSSIBILITIES. COLD FRONT WILL PASS EAST THROUGH THE AREA THIS AFTERNOON...EXITING THE SOUTHEAST BY MIDDLE TO LATE EVENING. SYNOPTIC MODELS VARY A BIT IN THE TIMING OF THE FRONT. FRONTOGENESIS RESPONSE WITH FRONT IS WEAK AS IT MOVES THROUGH THE AREA...THOUGH ELONGATED 500 MB VORTICITY MAXIMUM PUSHES INTO THE AREA FROM THE WEST. WENT WITH CHANCE POPS FOR THIS AFTERNOON...AND EVENING IN THE SOUTHEAST...AS THERE IS SOME UNCERTAINTY WITH THE AREAL COVERAGE OF CONVECTION WITH THE FRONT. IF MORNING PRECIPITATION CAN MOVE OUT AND CLOUDS BREAK UP THIS AFTERNOON...SHOULD SEE AT LEAST 1000 TO 1500 J/KG OF MEAN LAYER CAPE AND AROUND 50 KNOTS OR SO OF DEEP LAYER SHEAR. THIS IS CERTAINLY SUPPORTIVE OF SEVERE CONVECTION...WITH LARGE HAIL AND DAMAGING WINDS POSSIBLE. SPC HAS MOST OF THE AREA IN A SLIGHT RISK FOR SEVERE STORMS THIS AFTERNOON AND EARLY THIS EVENING. DRIER AIR WORKS INTO THE AREA LATER TONIGHT...BRINGING QUIETER WEATHER. HIGHS TODAY WILL DEPEND ON AMOUNT OF CLOUDS LINGERING FROM MORNING PRECIPITATION. WENT WITH UPPER 70S TO LOWER 80S FOR NOW. LOWS TONIGHT SHOULD DROP INTO THE UPPER 50S TO LOWER/MID 60S. TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE...HIGH IT LOOKS MAINLY DRY TUESDAY AND WEDNESDAY AS SURFACE HIGH PRESSURE SLIDES THROUGH THE AREA. DID ADD A SLIGHT CHANCE FOR SHOWERS/STORMS IN THE NORTH TUESDAY...AS MODELS NOW IN DECENT AGREEMENT WITH A WEAK SHORTWAVE PASSING THROUGH. WARM TEMPS WILL CONTINUE BOTH DAYS WITH HIGHS NEAR TO A FEW DEGREES ABOVE NORMAL. WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM BUMPED POPS UP WEDNESDAY NIGHT...AS MODELS ARE IN PRETTY GOOD AGREEMENT IN BRINGING STRONG WARM AIR ADVECTION INTO SOUTHERN WISCONSIN ON THE NOSE OF A 40-50 KT LLJ. LOOKS LIKE A SHORTWAVE WILL ALSO BE MOVING THROUGH...WHICH SHOULD HELP TO FIRE OFF SOME SHOWERS/STORMS. THE PRECIP MAY HANG ON INTO THURSDAY MORNING...WITH MOST MODELS THEN SHOWING A DRIER AND VERY WARM AFTERNOON IF THE SUN CAN COME OUT. MODEL 925 MB TEMPS GET UP TO AROUND 25-26C...WHICH WOULD RESULT IN HIGHS AROUND 90 GIVEN ENOUGH SUN. THROW IN DEWPOINTS IN THE LOW 70S AND IT COULD END UP BEING AN UNCOMFORTABLE EARLY SEPTEMBER DAY. THE COLD FRONT IS EXPECTED TO MOVE THROUGH THURSDAY NIGHT...BRINGING MORE THUNDERSTORM CHANCES. LINGERED SOME POPS INTO FRIDAY DUE TO A COUPLE MODELS BEING A BIT SLOWER WITH THE TIMING OF THE FRONT AND SHORTWAVE. SHOULD SEE HIGH TEMPS BACK DOWN TO AROUND NORMAL FOR FRIDAY. SATURDAY AND SUNDAY...FORECAST CONFIDENCE...MEDIUM IT LOOKS COOLER AND DRY SATURDAY AND SUNDAY AS HIGH PRESSURE SETTLES INTO THE GREAT LAKES REGION. TEMPERATURES WILL LIKELY BE A FEW DEGREES BELOW NORMAL IF CURRENT MODEL FORECASTS VERIFY. AVIATION/12Z TAFS/... AREA OF SHOWERS AND A FEW STORMS WILL SHIFT EAST NORTHEAST THROUGH THE AREA INTO THE MIDDLE MORNING HOURS. MAY SEE MVFR VISIBILITIES AND CEILINGS WITH THESE SHOWERS. GUSTY SOUTH SOUTHWEST WINDS ARE EXPECTED BY THE AFTERNOON HOURS...WITH GUSTS TO 25 KNOTS AT TIMES. COLD FRONT WILL PUSH EASTWARD THROUGH TAF SITES BETWEEN 21Z TODAY AND 03Z TUESDAY. SHOWERS AND STORMS ARE POSSIBLE ALONG AND AHEAD OF THE FRONT. STRONG/SEVERE STORMS ARE POSSIBLE WITH HAIL AND GUSTY WINDS. UNCERTAINTY EXISTS WITH THE AREAL COVERAGE OF STORMS...SO WILL JUST USE VICINITY THUNDER WORDING FOR NOW IN TAFS. MVFR/IFR VISIBILITIES AND CEILINGS ARE POSSIBLE IN ANY STORMS. QUIET WEATHER WILL RETURN AFTER THE FRONTAL PASSAGE AND LINGER THROUGH THE REST OF TONIGHT. LIGHT WINDS AND LINGERING MOISTURE MAY BRING MVFR/IFR FOG AND CEILINGS TO THE AREA AFTER 06Z TUESDAY. MARINE... CANCELLED MARINE DENSE FOG ADVISORY EARLY...AS INCREASING SOUTH WINDS SHOULD MIX OUT ANY LINGERING FOG NORTH OF NORTH POINT LIGHTHOUSE. SMALL CRAFT ADVISORY CONTINUES FOR THE NEARSHORE WATERS FROM 15Z UNTIL 23Z TODAY. TIGHT PRESSURE GRADIENT WILL ALLOW FOR GUSTY SOUTH SOUTHWEST WINDS TO 25 KNOTS AT TIMES. THIS WILL BRING WAVES OF 3 TO 5 FEET TOWARD THE OPEN WATERS. WINDS AND WAVES WILL SUBSIDE BY THIS EVENING. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR LMZ643>646. && $$ TODAY/TONIGHT AND AVIATION/MARINE...WOOD TUESDAY THROUGH SUNDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT MON SEP 1 2014 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 308 AM CDT MON SEP 1 2014 WATER VAPOR SATELLITE LOOP COUPLED WITH RAP ANALYSIS SHOWS VIGOROUS MID-LEVEL TROUGH ROTATING THROUGH THE PLAINS TOWARD THE UPPER MISSISSIPPI RIVER VALLEY. AT THE SURFACE 999MB LOWS WAS OVER WESTERN ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD THROUGH MN/NW IA/CENTRAL NEB. RADAR WAS LIT UP WITH SHOWERS/THUNDERSTORMS ACROSS EASTERN MN INTO THE FORECAST AREA AHEAD OF THE MID-LEVEL WAVE AND SURFACE COLD FRONT. OTHERWISE...TEMPERATURES ACROSS THE AREA EARLY THIS MORNING WERE IN THE 60S. LOOK FOR THE SURFACE COLD FRONT AND ASSOCIATED CONVECTION TO CONTINUE PUSHING EAST ACROSS THE AREA THIS MORNING WITH THE BULK OF THE RAIN EXITING EAST BY LATE MORNING. KEPT LINGERING AND DIMINISHING CHANCES GOING HOWEVER INTO THE AFTERNOON AS THE MID- LEVEL TROUGH/COLD AIR ALOFT POSSIBLY POPPING A FEW INSTABILITY SHOWERS AND THUNDERSTORMS. NOT EXPECTING ANY SEVERE THREAT AS BEST CAPE AND WIND SHEAR SHIFT EAST/SOUTHEAST OF THE AREA. FOR TONIGHT...WILL SEE ANOTHER WEAK MID-LEVEL WAVE ROTATE TOWARD THE AREA FROM THE NORTHERN PLAINS. NAM SHOWING A DECENT SHOT OF 700- 300MB PVA MOVING IN MAINLY WEST OF THE MISSISSIPPI RIVER AFTER MIDNIGHT WITH BUFKIT SHOWING INSTABILITY/MOISTURE MAINLY CONFINED ABOVE 800MB. KEPT A SMALL-END CHANCE OF SHOWERS/ISOLATED WEST OF THE MISSISSIPPI AFTER MIDNIGHT BASED ON THIS SIGNAL. OVERNIGHT LOWS ARE EXPECTED TO FALL INTO THE 50S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 308 AM CDT MON SEP 1 2014 A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO TUESDAY MAINLY NORTH OF I-94 AS THE WEAK MID-LEVEL TROUGH ROTATES ACROSS THE FORECAST AREA. PLAN ON HIGHS RANGING FROM THE MIDDLE 70S ACROSS NORTH CENTRAL WI...TO THE UPPER 70S/LOWER 80S ELSEWHERE. SURFACE CYCLOGENESIS OVER THE NORTHERN PLAINS WILL PUSH A WARM FRONT TOWARD THE AREA WEDNESDAY/WEDNESDAY NIGHT. ALL MODELS SHOW INCREASING 850MB MOISTURE TRANSPORT/WARM AIR ADVECTION NOSING INTO THE AREA WITH THE FRONT FOR INCREASING COVERAGE OF THUNDERSTORMS. PRECIPITABLE WATER VALUES PUSHING 1.9 INCHES BY THURSDAY MORNING WITH WARM CLOUD DEPTH LAYERS INCREASING INTO THE 4-4.5KM RANGE. BASED ON THIS SIGNAL...WILL HAVE TO WATCH FOR A HEAVY RAINFALL POTENTIAL ALONG WITH OTHER SEVERE THREATS AS WELL AS CAPE AND BULK SHEAR INCREASE ALONG THE WARM FRONT. AT THIS POINT...MODELS SHOWING HIGHER SEVERE POTENTIAL STAYING WEST OF THE MISSISSIPPI RIVER IN MORE FAVORABLE CAPE/SHEAR ENVIRONMENT. WILL HAVE TO KEEP A CLOSE ON THIS OVER THE NEXT COUPLE DAYS. LOOK FOR HIGHS ON WEDNESDAY TO TOP OFF IN THE UPPER 70S TO MIDDLE 80S WITH DEW POINTS CREEPING UP INTO THE 65- 70 DEGREE RANGE. THUNDERSTORM CHANCES CONTINUE THURSDAY INTO THURSDAY NIGHT AS THE LOW PULLS NORTHEAST INTO ONTARIO CANADA...PUSHING A COLD FRONT THROUGH THE AREA. THURSDAY WILL HAVE TO BE WATCHED CLOSELY AS WELL FOR SEVERE POTENTIAL AS THE GFS IS SHOWING 0-6KM BULK SHEAR OF 30- 50KT COUPLED WITH MUCAPE POOL OF 2500-4500J/KG. HIGHS ON THURSDAY AHEAD OF THE COLD FRONT ARE EXPECTED TO TOP OFF WELL INTO THE 80S WITH DEW POINTS IN THE 70-75 DEGREE RANGE. DRIER/COOLER AIR FILTERS INTO THE AREA FRIDAY AND INTO THE WEEKEND AS CANADIAN HIGH PRESSURE BUILD INTO THE REGION. PLAN ON TEMPERATURES BY THIS WEEKEND TO FEEL A BIT MORE LIKE FALL WITH HIGHS IN THE 60S/LOWER 70S AND LOWS IN THE 50S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 618 AM CDT MON SEP 1 2014 SECOND ROUND OF CONVECTION HAS FORMED AHEAD OF THE FRONT AND EXPECT THIS TO MOVE THROUGH BEFORE 12Z AT KRST AND KLSE BY 14Z. IFR CONDITIONS WILL BE POSSIBLE IN THIS ACTIVITY. THE FRONT IS THEN EXPECTED TO PUSH THROUGH SHORTLY BEHIND THE CONVECTION SWINGING THE WINDS AROUND TO THE WEST AND ALLOWING AN AREA OF MVFR CEILINGS TO MOVE IN. BOTH THE 01.06Z NAM AND 01.09Z RAP SUGGEST THESE CEILINGS WILL ONLY LAST THROUGH THE MORNING BEFORE SCATTERING OUT WITH VFR CONDITIONS THEN EXPECTED THROUGH THE REST OF THE PERIOD. SOME CONCERN FOR FOG DEVELOPMENT LATE TONIGHT...ESPECIALLY AT KLSE. FORECAST SOUNDINGS FROM THE NAM INDICATE SATURATION MAY OCCUR AT THE SURFACE WITH A LIGHT WIND PROFILE UP THROUGH ABOUT 25OO FEET OR SO. HOWEVER...UNSURE HOW MUCH MID AND HIGH LEVEL CLOUDS MAY BE AROUND AHEAD OF AN APPROACHING WEAK SHORT WAVE TROUGH. WILL LET LATER SHIFTS ACCESS THIS POTENTIAL AND ADD IF NEEDED. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...04
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
355 AM CDT MON SEP 1 2014 .TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM. AREA OF RAIN SHOWERS AND A FEW THUNDERSTORMS OVER SOUTHWEST WISCONSIN...INTO FAR EASTERN IOWA AND FAR NORTHWEST ILLINOIS...HAS BEEN SLOWLY WEAKENING OVER THE PAST FEW HOURS. THIS WAS BEING DRIVEN BY 500 MB VORTICITY MAXIMUM MOVING INTO THE AREA...UPPER DIVERGENCE WITH RIGHT REAR QUADRANT OF 250 MB JET STREAK...ALONG WITH 850 MB LOW LEVEL JET. SPC MESOANALYSIS PAGE SHOWING A GOOD AMOUNT OF CONVECTIVE INHIBITION OVER THE AREA...WHICH MAY BE HELPING WEAKEN CONVECTION. STILL...THE ABOVE MAIN FEATURES SHOULD CONTINUE TO BRING SOME SHOWERS ACROSS THE AREA THROUGH THE MIDDLE MORNING HOURS. THIS IS SUPPORTED BY THE HRRR AND OTHER MESOSCALE MODELS...THOUGH THEY AREA SOMEWHAT OVERDONE WITH CURRENT PRECIPITATION TRENDS. THUS...WILL CONTINUE HIGH POPS THROUGH THE MIDDLE MORNING HOURS FOR SHOWERS AND ISOLATED STORMS. MAIN ISSUE WILL BE CONVECTIVE TRENDS THIS AFTERNOON AND EVENING WITH PASSING COLD FRONT AND SEVERE WEATHER POSSIBILITIES. COLD FRONT WILL PASS EAST THROUGH THE AREA THIS AFTERNOON...EXITING THE SOUTHEAST BY MIDDLE TO LATE EVENING. SYNOPTIC MODELS VARY A BIT IN THE TIMING OF THE FRONT. FRONTOGENESIS RESPONSE WITH FRONT IS WEAK AS IT MOVES THROUGH THE AREA...THOUGH ELONGATED 500 MB VORTICITY MAXIMUM PUSHES INTO THE AREA FROM THE WEST. WENT WITH CHANCE POPS FOR THIS AFTERNOON...AND EVENING IN THE SOUTHEAST...AS THERE IS SOME UNCERTAINTY WITH THE AREAL COVERAGE OF CONVECTION WITH THE FRONT. IF MORNING PRECIPITATION CAN MOVE OUT AND CLOUDS BREAK UP THIS AFTERNOON...SHOULD SEE AT LEAST 1000 TO 1500 J/KG OF MEAN LAYER CAPE AND AROUND 50 KNOTS OR SO OF DEEP LAYER SHEAR. THIS IS CERTAINLY SUPPORTIVE OF SEVERE CONVECTION...WITH LARGE HAIL AND DAMAGING WINDS POSSIBLE. SPC HAS MOST OF THE AREA IN A SLIGHT RISK FOR SEVERE STORMS THIS AFTERNOON AND EARLY THIS EVENING. DRIER AIR WORKS INTO THE AREA LATER TONIGHT...BRINGING QUIETER WEATHER. HIGHS TODAY WILL DEPEND ON AMOUNT OF CLOUDS LINGERING FROM MORNING PRECIPITATION. WENT WITH UPPER 70S TO LOWER 80S FOR NOW. LOWS TONIGHT SHOULD DROP INTO THE UPPER 50S TO LOWER/MID 60S. .TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE...HIGH IT LOOKS MAINLY DRY TUESDAY AND WEDNESDAY AS SURFACE HIGH PRESSURE SLIDES THROUGH THE AREA. DID ADD A SLIGHT CHANCE FOR SHOWERS/STORMS IN THE NORTH TUESDAY...AS MODELS NOW IN DECENT AGREEMENT WITH A WEAK SHORTWAVE PASSING THROUGH. WARM TEMPS WILL CONTINUE BOTH DAYS WITH HIGHS NEAR TO A FEW DEGREES ABOVE NORMAL. .WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM BUMPED POPS UP WEDNESDAY NIGHT...AS MODELS ARE IN PRETTY GOOD AGREEMENT IN BRINGING STRONG WARM AIR ADVECTION INTO SOUTHERN WISCONSIN ON THE NOSE OF A 40-50 KT LLJ. LOOKS LIKE A SHORTWAVE WILL ALSO BE MOVING THROUGH...WHICH SHOULD HELP TO FIRE OFF SOME SHOWERS/STORMS. THE PRECIP MAY HANG ON INTO THURSDAY MORNING...WITH MOST MODELS THEN SHOWING A DRIER AND VERY WARM AFTERNOON IF THE SUN CAN COME OUT. MODEL 925 MB TEMPS GET UP TO AROUND 25-26C...WHICH WOULD RESULT IN HIGHS AROUND 90 GIVEN ENOUGH SUN. THROW IN DEWPOINTS IN THE LOW 70S AND IT COULD END UP BEING AN UNCOMFORTABLE EARLY SEPTEMBER DAY. THE COLD FRONT IS EXPECTED TO MOVE THROUGH THURSDAY NIGHT...BRINGING MORE THUNDERSTORM CHANCES. LINGERED SOME POPS INTO FRIDAY DUE TO A COUPLE MODELS BEING A BIT SLOWER WITH THE TIMING OF THE FRONT AND SHORTWAVE. SHOULD SEE HIGH TEMPS BACK DOWN TO AROUND NORMAL FOR FRIDAY. .SATURDAY AND SUNDAY...FORECAST CONFIDENCE...MEDIUM IT LOOKS COOLER AND DRY SATURDAY AND SUNDAY AS HIGH PRESSURE SETTLES INTO THE GREAT LAKES REGION. TEMPERATURES WILL LIKELY BE A FEW DEGREES BELOW NORMAL IF CURRENT MODEL FORECASTS VERIFY. && .AVIATION/12Z TAFS/... AREA OF SHOWERS AND A FEW STORMS WILL SHIFT EAST NORTHEAST THROUGH THE AREA INTO THE MIDDLE MORNING HOURS. MAY SEE MVFR VISIBILITIES AND CEILINGS WITH THESE SHOWERS. GUSTY SOUTH SOUTHWEST WINDS ARE EXPECTED BY THE AFTERNOON HOURS...WITH GUSTS TO 25 KNOTS AT TIMES. COLD FRONT WILL PUSH EASTWARD THROUGH TAF SITES BETWEEN 21Z TODAY AND 03Z TUESDAY. SHOWERS AND STORMS ARE POSSIBLE ALONG AND AHEAD OF THE FRONT. STRONG/SEVERE STORMS ARE POSSIBLE WITH HAIL AND GUSTY WINDS. UNCERTAINTY EXISTS WITH THE AREAL COVERAGE OF STORMS...SO WILL JUST USE VICINITY THUNDER WORDING FOR NOW IN TAFS. MVFR/IFR VISIBILITIES AND CEILINGS ARE POSSIBLE IN ANY STORMS. QUIET WEATHER WILL RETURN AFTER THE FRONTAL PASSAGE AND LINGER THROUGH THE REST OF TONIGHT. LIGHT WINDS AND LINGERING MOISTURE MAY BRING MVFR/IFR FOG AND CEILINGS TO THE AREA AFTER 06Z TUESDAY. && .MARINE... CANCELLED MARINE DENSE FOG ADVISORY EARLY...AS INCREASING SOUTH WINDS SHOULD MIX OUT ANY LINGERING FOG NORTH OF NORTH POINT LIGHTHOUSE. SMALL CRAFT ADVISORY CONTINUES FOR THE NEARSHORE WATERS FROM 15Z UNTIL 23Z TODAY. TIGHT PRESSURE GRADIENT WILL ALLOW FOR GUSTY SOUTH SOUTHWEST WINDS TO 25 KNOTS AT TIMES. THIS WILL BRING WAVES OF 3 TO 5 FEET TOWARD THE OPEN WATERS. WINDS AND WAVES WILL SUBSIDE BY THIS EVENING. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM CDT THIS EVENING FOR LMZ643>646. && $$ TODAY/TONIGHT AND AVIATION/MARINE...WOOD TUESDAY THROUGH SUNDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
308 AM CDT MON SEP 1 2014 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 308 AM CDT MON SEP 1 2014 WATER VAPOR SATELLITE LOOP COUPLED WITH RAP ANALYSIS SHOWS VIGOROUS MID-LEVEL TROUGH ROTATING THROUGH THE PLAINS TOWARD THE UPPER MISSISSIPPI RIVER VALLEY. AT THE SURFACE 999MB LOWS WAS OVER WESTERN ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD THROUGH MN/NW IA/CENTRAL NEB. RADAR WAS LIT UP WITH SHOWERS/THUNDERSTORMS ACROSS EASTERN MN INTO THE FORECAST AREA AHEAD OF THE MID-LEVEL WAVE AND SURFACE COLD FRONT. OTHERWISE...TEMPERATURES ACROSS THE AREA EARLY THIS MORNING WERE IN THE 60S. LOOK FOR THE SURFACE COLD FRONT AND ASSOCIATED CONVECTION TO CONTINUE PUSHING EAST ACROSS THE AREA THIS MORNING WITH THE BULK OF THE RAIN EXITING EAST BY LATE MORNING. KEPT LINGERING AND DIMINISHING CHANCES GOING HOWEVER INTO THE AFTERNOON AS THE MID- LEVEL TROUGH/COLD AIR ALOFT POSSIBLY POPPING A FEW INSTABILITY SHOWERS AND THUNDERSTORMS. NOT EXPECTING ANY SEVERE THREAT AS BEST CAPE AND WIND SHEAR SHIFT EAST/SOUTHEAST OF THE AREA. FOR TONIGHT...WILL SEE ANOTHER WEAK MID-LEVEL WAVE ROTATE TOWARD THE AREA FROM THE NORTHERN PLAINS. NAM SHOWING A DECENT SHOT OF 700- 300MB PVA MOVING IN MAINLY WEST OF THE MISSISSIPPI RIVER AFTER MIDNIGHT WITH BUFKIT SHOWING INSTABILITY/MOISTURE MAINLY CONFINED ABOVE 800MB. KEPT A SMALL-END CHANCE OF SHOWERS/ISOLATED WEST OF THE MISSISSIPPI AFTER MIDNIGHT BASED ON THIS SIGNAL. OVERNIGHT LOWS ARE EXPECTED TO FALL INTO THE 50S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 308 AM CDT MON SEP 1 2014 A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO TUESDAY MAINLY NORTH OF I-94 AS THE WEAK MID-LEVEL TROUGH ROTATES ACROSS THE FORECAST AREA. PLAN ON HIGHS RANGING FROM THE MIDDLE 70S ACROSS NORTH CENTRAL WI...TO THE UPPER 70S/LOWER 80S ELSEWHERE. SURFACE CYCLOGENESIS OVER THE NORTHERN PLAINS WILL PUSH A WARM FRONT TOWARD THE AREA WEDNESDAY/WEDNESDAY NIGHT. ALL MODELS SHOW INCREASING 850MB MOISTURE TRANSPORT/WARM AIR ADVECTION NOSING INTO THE AREA WITH THE FRONT FOR INCREASING COVERAGE OF THUNDERSTORMS. PRECIPITABLE WATER VALUES PUSHING 1.9 INCHES BY THURSDAY MORNING WITH WARM CLOUD DEPTH LAYERS INCREASING INTO THE 4-4.5KM RANGE. BASED ON THIS SIGNAL...WILL HAVE TO WATCH FOR A HEAVY RAINFALL POTENTIAL ALONG WITH OTHER SEVERE THREATS AS WELL AS CAPE AND BULK SHEAR INCREASE ALONG THE WARM FRONT. AT THIS POINT...MODELS SHOWING HIGHER SEVERE POTENTIAL STAYING WEST OF THE MISSISSIPPI RIVER IN MORE FAVORABLE CAPE/SHEAR ENVIRONMENT. WILL HAVE TO KEEP A CLOSE ON THIS OVER THE NEXT COUPLE DAYS. LOOK FOR HIGHS ON WEDNESDAY TO TOP OFF IN THE UPPER 70S TO MIDDLE 80S WITH DEW POINTS CREEPING UP INTO THE 65- 70 DEGREE RANGE. THUNDERSTORM CHANCES CONTINUE THURSDAY INTO THURSDAY NIGHT AS THE LOW PULLS NORTHEAST INTO ONTARIO CANADA...PUSHING A COLD FRONT THROUGH THE AREA. THURSDAY WILL HAVE TO BE WATCHED CLOSELY AS WELL FOR SEVERE POTENTIAL AS THE GFS IS SHOWING 0-6KM BULK SHEAR OF 30- 50KT COUPLED WITH MUCAPE POOL OF 2500-4500J/KG. HIGHS ON THURSDAY AHEAD OF THE COLD FRONT ARE EXPECTED TO TOP OFF WELL INTO THE 80S WITH DEW POINTS IN THE 70-75 DEGREE RANGE. DRIER/COOLER AIR FILTERS INTO THE AREA FRIDAY AND INTO THE WEEKEND AS CANADIAN HIGH PRESSURE BUILD INTO THE REGION. PLAN ON TEMPERATURES BY THIS WEEKEND TO FEEL A BIT MORE LIKE FALL WITH HIGHS IN THE 60S/LOWER 70S AND LOWS IN THE 50S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1144 PM CDT SUN AUG 31 2014 01.0430Z RADAR SHOWS A LARGE SWATH OF MODERATE TO HEAVY RAIN WITH EMBEDDED THUNDER ALONG AND WEST OF THE MISSISSIPPI RIVER. BACK EDGE OF THIS PRECIPITATION IS JUST WEST OF KRST SUCH THAT DRY CONDITIONS ARE EXPECTED NO LATER THAN 01.07Z AT KRST AND 01.09Z AT KLSE. WITH SATURATED NEAR SURFACE LAYER...EXPECT CEILINGS TO LOWER OVERNIGHT WITH MVFR VISIBILITY IN MIST. CONDITIONS EXPECTED TO SLOWLY IMPROVE LABOR DAY MORNING...BUT REMAIN MVFR THROUGH MUCH OF THE DAY...FINALLY IMPROVING TO VFR BY 02.00Z. WINDS WILL SHIFT TO THE NORTHWEST AFTER FRONTAL PASSAGE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1154 PM CDT SUN AUG 31 2014 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE AND NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 1148 PM CDT SUN AUG 31 2014 HAVE CONTINUED TO HIT LOWER VISBY AT LAKESHORE WITH SPS AS NOT WIDESPREAD ENOUGH TO GO WITH ADVISORY. IS STARTING TO IMPROVE IN MANITOWOC AND WILL CONTIUE TO IMPROVE NEXT HOUR OR SO. WILL BE WATCHING AREA OF STORMS/SHOWERS MOVING THROUGH SOUTHERN WI. WINDS AT LEAD EDGE STILL RATHER STRONG. && .SYNOPSIS... ISSUED AT 218 PM CDT SUN AUG 31 2014 WARM AND RATHER HUMID WITH SHOWERS AND THUNDERSTORMS AT TIMES FOR THE REST OF THE HOLIDAY WEEKEND AND THROUGH THE UPCOMING WORK WEEK. STG SUBTROPICAL RIDGE ACRS THE SRN CONUS WL EXPAND NWD A BIT AS SOMEWHAT PROGRESSIVE BAND OF WESTERLIES GRADUALLY RECEDES NWD DURING THE PERIOD. NOTHING SPECIAL ABOUT THIS PATTERN FOR THIS TIME OF YEAR...AS THE WESTERLIES ARE TYPICALLY STRONGER THAN DURING THE MIDDLE SUMMER...BUT ARE STILL USUALLY CENTERED N OF THE AREA. THE PRIMARY FRONTAL ZONE SEPARATING WARM AND VERY MOIST TROPICAL AIR TO THE S FM COOLER AND DRIER CANADIAN AIR TO THE N WL REMAIN STETCHED OUT W-E ALONG THE SRN EDGE OF THE MAIN WESTERLIES...AND CLOSE TO THE FCST AREA MUCH OF THE TIME. THIS WL RESULT IN SEVERAL OPPORTUNITIES FOR PCPN...LIKELY RESULTING IN ABV NORMAL AMNTS. TEMPS ARE EXPECTED TO REMAIN AOA NORMAL FOR MUCH OF THE FCST PERIOD BEFORE DROPPING BACK CLOSE TO NORMAL LATE. IT WILL ALSO BE HUMID AT TIMES. && .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 218 PM CDT SUN AUG 31 2014 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE MOVING NORTHEAST OVER FAR NORTHWEST MINNESOTA AND A COLD FRONT MOVING EASTWARD FROM THE LOW TO THE CENTRAL GREAT PLAINS. STORMS HAVE BEGUN TO FIRE ALONG THE FRONT OVER SOUTH CENTRAL MINNESOTA...BUT THE ATMOSPHERE IS STRUGGLING TO DESTABILIZE DUE IN PART TO A PRONOUNCED CAP AND DRY AIR ON THE 18Z MINNEAPOLIS SOUNDING. HOWEVER...AS A SHORTWAVE OVER NEBRASKA MOVES INTO THE NORTHERN MISSISSIPPI VALLEY...THE CAP IS EXPECTED TO WEAKEN LATE THIS AFTERNOON THAT WILL RESULT IN A FAVORABLE ENVIRONMENT FOR SEVERE STORMS. THESE STORMS COULD MOVE INTO NORTH-CENTRAL WISCONSIN LATER THIS EVENING. THE MAIN SHORTWAVE IS MOVING EAST OVER EASTERN WYOMING AND ANTICIPATED TO ARRIVE INTO WISCONSIN LATE TONIGHT INTO MONDAY MORNING...ALONG WITH THE COLD FRONT. THUNDERSTORM TIMING AND IMPACTS ARE THE MAIN FORECAST CONCERNS. TONIGHT...A COLD FRONT WILL SLOWLY MOVE ACROSS THE NORTHERN MISSISSIPPI VALLEY AS IT WAITS FOR A SHORTWAVE OVER WYOMING TO GIVE IT A FORWARD PUSH. ASSUMING STRONG TO SEVERE CONVECTION AHEAD OF THE FRONT DEVELOPS AS PLANNED LATER THIS AFTERNOON INTO THIS EVENING...GUIDANCE SUGGESTS THIS CONVECTION WILL MAKE A RUN AT NORTH-CENTRAL WISCONSIN LATE THIS EVENING...THOUGH WILL BE WEAKENING AS DIURNAL INSTABILITY IS LOST. MODELS SUGGEST AROUND 1000 J/KG OF ELEVATED CAPE WILL BE PRESENT AS THIS CONVECTION APPROACHES THE NORTHWEST FORECAST AREA SO NOT OUT OF THE QUESTION THAT A FEW STRONG STORMS COULD REACH NORTH-CENTRAL WISCONSIN. AN ISOLATED SEVERE STORM CANNOT BE RULED OUT...MAINLY FOR DAMAGING WINDS AND LARGE HAIL. WOULDNT BE SURPRISE TO SEE A FEW HOUR BREAK OVERNIGHT BETWEEN THIS CONVECTION AS IT WEAKENS/LIFTS TO THE NORTHEAST...AND A MORE WIDESPREAD AREA OF SHOWERS AND THUNDERSTORMS AHEAD OF THE MAIN SHORTWAVE WHICH WILL MOVE INTO THE NORTHERN MISSISSIPPI VALLEY BY 12Z. THIS AREA OF PRECIP SHOULD MOVE ACROSS CENTRAL AND NORTH-CENTRAL WI LATE TONIGHT. ELEVATED CAPES LOOK TO BE APPROX 500 J/KG SO NOT ANTICIPATING SEVERE CONVECTION. LOWS MAINLY IN THE MIDDLE 60S. MONDAY...THE SHORTWAVE TROUGH WILL LIFT NORTHEAST ACROSS WISCONSIN MONDAY MORNING...DRIVING THE AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH-CENTRAL AND NORTHEAST WISCONSIN. THE HEAVIEST RAINFALL LOOKS TO OCCUR OVER CENTRAL AND NORTH-CENTRAL WISCONSIN WITH THIS EVENT AND COULD SEE AN INCH TO 1.50 INCHES IF CONVECTION REACHES INTO THIS AREA THIS EVENING. WITH PRECIPITATION OCCURRING DURING THE MORNING AND THE SHORTWAVE LIFTING NORTHEAST OF THE AREA IN THE AFTERNOON...SEEMS LIKE AN AWFULLY SMALL TIME PERIOD FOR REDEVELOPMENT OF STORMS ALONG THE COLD FRONT OVER NORTHEAST WISCONSIN. THE BEST BET MAY BE TO HAVE STORMS CONTINUOUSLY REFIRE ALONG THE TAIL OF THE SHORTWAVE...BUT THIS ADMITTEDLY SEEMS LIKE A SMALL CHANCE SINCE THE ATMOSPHERE WILL HAVE BEEN WORKED OVER BY THIS TIME...AND PRECIPITATION WILL HAVE SQUASHED SURFACE BASED INSTABILITY. AS A RESULT...SPC HAS SHIFTED THE SLIGHT RISK OF SEVERE WEATHER TO THE SOUTH AND EAST OF THE FORECAST AREA AND THIS SEEMS REASONABLE. WILL MENTION THE CHANCE OF GUSTY WINDS AND SMALL HAIL BUT LEAVE THE THREAT OF SEVERE WEATHER OUT OF THE HWO. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 218 PM CDT SUN AUG 31 2014 SOME LINGERING PCPN WL BE POSSIBLE MON EVENING...MAINLY OVER E-C WI. CARRIED CHC POPS INTO THE EARLY EVENING. WHILE ISOLD SHRA COULD LINGER WELL INTO THE NGT...THE MAIN POOL OF INSTABILITY WL BE WELL S BY THEN...SO OPTED TO GO WITH A DRY FCST AFTER MIDNIGHT. LATER SHIFTS MAY NEED TO TAKE ANOTHER LOOK AT THAT. THERE ARE PROS AND CONS FOR PCPN CHCS TUE. ON ONE HAND...UPR TROF WL STILL BE ACRS THE AREA DURING THE MORNING...AND WNWLY UPR FLOW WL KEEP MODEST MID-LVL LAPSE RATES ACRS THE RGN. ON THE OTHER... UPR HEIGHTS WL BE RISING AS THE TROF SHIFTS E...AND QG FORCING WL BE FAVORING SUBSIDENCE. OPTED TO KEEP FAIRLY LOW POPS...BUT WENT WITH ISOLD SHRA ACRS ALL BUT THE FAR SRN PART OF THE AREA. PCPN UNLIKELY TO BE A BIG DEAL...BUT CONFIDENCE IN TOTALLY DRY DAY ISN/T THAT GREAT EITHER. UPR HEIGHTS SHOULD CONT TO RISE TUE NGT/WED. STAYED DRY TUE NGT... BUT N-C WI WL BE CLOSE ENOUGH TO THE RETURN FLOW TO JUSTIFY HAVING A CHC OF TSRA WED. WENT WITH A BLEND OF TOP PERFORING GUIDANCE PRODUCTS FOR TEMPS... WHICH WERE DOMINATED BY THE ECMWF AND IT/S MOS AND BIAS-CORRECTED DERIVATIVES. NO SIG CHGS NEED TO BROAD-BASED EXTENDED FCST INITIALIZATION GRIDS. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1148 PM CDT SUN AUG 31 2014 IMPROVING CONDITIONS AT LAKESHORE AS WINDS INCREASE OVERNIGHT. SHOWERS AND STROMS AHEAD OF A COLD FRONT WILL MOVE ACROSS THE REGION LATE TONIGHT INTO MONDAY...SCATTERED MVFR CIGS AND VSBYS...LOCALLY IFR...WILL DEVELOP DUE TO HEAVY RAIN AND POSSIBLE THUNDERSTORMS. SOME STORMS MAY CONTAIN STRONG GUSTY WINDS AS THEY MOVE INTO CENTRAL AND NORTH-CENTRAL WISCONSIN OVERNIGHT. HAVE ADDED SOME LLWS AS LOW LEVEL JET STRENGTHENS OVERNIGHT. IMPROVING CONDITIONS EXPECTED BY MON AFTN. && .GRB WATCHES/WARNINGS/ADVISORIES... BEACH HAZARDS STATEMENT FROM 8 AM CDT MONDAY THROUGH MONDAY EVENING FOR WIZ022-040-050. && $$ UPDATE.........TE SYNOPSIS.......SKOWRONSKI SHORT TERM.....MPC LONG TERM......SKOWRONSKI AVIATION.......TE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
657 PM MDT TUE SEP 2 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 420 PM MDT TUE SEP 2 2014 MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE CRITICAL FIRE WEATHER CONDITIONS ACROSS THE CWA. IT TOOK A LITTLE WHILE FOR RH VALUES TO DROP TO CRITICAL LEVELS THIS AFTERNOON...BUT WE ARE CURRENTLY SEEING A RH OF AROUND 15 PERCENT IN THE FOOTHILLS OF THE LARAMIE RANGE (FIRE WEATHER ZONES 309 AND 301). RH VALUES ARE GENERALLY 15-20 PERCENT TO THE WEST OF THE LARAMIE RANGE. WITH GUSTS TO 25-30 MPH THROUGH EARLY EVENING...THIS CONTINUES TO LOOK LIKE A MARGINAL RED FLAG EVENT AND WILL KEEP THE WARNINGS GOING. CLOUD COVER THIS AFTERNOON IS QUITE LIMITED WITH ONLY ISOLATED CUMULUS. SFC MOISTURE IS BETTER IN SOUTHERLY WINDS JUST TO THE EAST OF THE CWA (DEUEL AND GARDEN COUNTIES) BUT IT WILL BE TOUGH TO ADVECT THIS MOISTURE WESTWARD. THE HRRR MODEL ALONG WITH THE OTHER MODELS DO NOT SHOW ANY QPF OVER THE PANHANDLE TONIGHT SO WILL KEEP SLIGHT CHANE POPS OUT OF THE FCST. WEDNESDAY CONTINUES TO LOOK LIKE A MORE CRITICAL FIRE WEATHER DAY OVER THE REGION. A SHORTWAVE MOVING FROM WASHINGTON INTO MONTANA WILL INDUCE PRESSURE FALLS OVER WESTERN SOUTH DAKOTA WHICH STRENGTHENS THE PRESSURE GRADIENT OVER ESPECIALLY SOUTHEAST WY. MOS GUIDANCE SHOWS WINDS ABOUT 5 KTS HIGHER THAN THIS AFTN ALONG WITH AN ADDITIONAL 5 DEGREES OF WARMING. THE FIRE WEATHER WATCH FOR TOMORROW AFTN INCLUDES TWO ZONES (310 AND 306) THAT ARE NOT INCLUDED IN TODAYS RED FLAG WARNING. THIS LOOKS GOOD SINCE BOTH THESE ZONES WERE CLOSE TO HITTING THE CRITERIA TODAY AND CONDITIONS WILL BE DRIER AND MORE BREEZY TOMORROW. THE DEEP SOUTHWESTERLY FLOW WILL RESULT IN A VERY WARM DAY WITH HIGHS RISING INTO THE UPPER 80S TO MID 90S ACROSS THE PLAINS. THIS COULD BE ONE OF THE WARMEST DAYS FOR THE REST OF THE YEAR SINCE A COLD FRONTAL PASSAGE IS STILL PROGGED FOR THURS MORNING. TEMPS WILL DROP CLOSE TO 20 DEGREES ON THURS. STILL NO GOOD CHANCE OF PRECIP THROUGH AT LEAST THURS EVENING. COULD BE ISOLATED SHOWERS DEVELOPING BY THURS NIGHT ALTHOUGH THE MODEL TREND HAS BEEN TO SHIFT THE MORE WIDESPREAD RAIN WELL TO THE SOUTH OVER NORTHWEST KS. .LONG TERM...(FRIDAY THROUGH MONDAY NIGHT) ISSUED AT 420 PM MDT TUE SEP 2 2014 MODELS ARE IN FAIR AGREEMENT WITH THE MEDIUM RANGE PERIOD SHOWING A PERSISTENT QUASI-ZONAL PATTERN OVER THE CENTRAL CONUS. TEMPERATURES WILL START OFF BELOW AVERAGE ON FRIDAY IN THE POST FRONTAL AIRMASS...WITH THE SFC HIGH SLIDING TO THE SOUTHEAST ACROSS THE CENTRAL PLAINS. SFC WINDS ACROSS THE HIGH PLAINS WILL BE OUT OF THE SOUTHEAST AS THE SFC HIGH SLIDES SOUTHEAST...WITH CONVECTION DEVELOPING OVER THE MOUNTAINS IN THE LATE AFTERNOON IN THIS LLVL UPSLOPE REGIME. SHOULD STAY FAIRLY CAPPED ACROSS THE PLAINS WITHIN THE COOLER AIRMASS...BUT CANT RULE OUT SHOWERS/WEAK TSTORMS MAINTAINING AS THEY MOVE OFF THE MOUNTAINS AS A 70 KT JET AND SHORTWAVE ENERGY WILL BE MOVING OVERHEAD AT THIS TIME. SATURDAY LOOKS VERY SIMILAR ALBEIT WITH WEAKER UPSLOPE FLOW AND SLIGHTLY WARMER TEMPS/HIGH INSTABILITY. SUNDAY AND MONDAY COULD SEE A BIT MORE SUBTROPICAL MOISTURE ADVECT UP FROM THE SOUTHWEST AS A TROUGH DIGS ALONG THE WEST COAST AND MOVES ACROSS THE GREAT BASIN. THE DEEPEST MOISTURE LOOKS TO REMAIN TO OUR SOUTH...BUT CAN SEE SOME OF THIS MOISTURE MAKING IT UP TO SOUTHERN PORTIONS OF THE CWA SO WILL MAINTAIN AT LEAST SLIGHT CHANCE POPS FOR MUCH OF THE CWA. TEMPS WILL INCREASE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR BY MONDAY AS THE UPPER TROUGH DEEPENS AND A WARM AIR ADVECTION PATTERN DEVELOPS OVER THE ROCKIES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON) ISSUED AT 644 PM MDT TUE SEP 2 2014 VFR CONDITIONS TO PREVAIL THRU THE PERIOD. WINDS WILL SUBSIDE AROUND 02Z...BUT BECOME GUSTY AFTER 16Z WEDNESDAY. && .FIRE WEATHER... ISSUED AT 649 PM MDT TUE SEP 2 2014 PER OUR FIRE WEATHER BRIEFING AND MODEL GUIDANCE...RED FLAG CONDITIONS LOOKING EVEN MORE LIKELY FOR PORTIONS OF SOUTHEAST WYOMING ON WEDNESDAY...THUS WE HAVE UPGRADED THE FIRE WEATHER WATCH TO A RED FLAG WARNING...AND HAVE ALSO CANCELLED THE RED FLAG WARNING THAT WAS IN EFFECT FOR THIS AFTERNOON. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...RED FLAG WARNING FROM NOON TO 7 PM MDT WEDNESDAY FOR WYZ301-302- 304-306-309-310. NE...NONE. && $$ SHORT TERM...FINCH LONG TERM...RJM AVIATION...HAHN FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
644 PM MDT TUE SEP 2 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 420 PM MDT TUE SEP 2 2014 MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE CRITICAL FIRE WEATHER CONDITIONS ACROSS THE CWA. IT TOOK A LITTLE WHILE FOR RH VALUES TO DROP TO CRITICAL LEVELS THIS AFTERNOON...BUT WE ARE CURRENTLY SEEING A RH OF AROUND 15 PERCENT IN THE FOOTHILLS OF THE LARAMIE RANGE (FIRE WEATHER ZONES 309 AND 301). RH VALUES ARE GENERALLY 15-20 PERCENT TO THE WEST OF THE LARAMIE RANGE. WITH GUSTS TO 25-30 MPH THROUGH EARLY EVENING...THIS CONTINUES TO LOOK LIKE A MARGINAL RED FLAG EVENT AND WILL KEEP THE WARNINGS GOING. CLOUD COVER THIS AFTERNOON IS QUITE LIMITED WITH ONLY ISOLATED CUMULUS. SFC MOISTURE IS BETTER IN SOUTHERLY WINDS JUST TO THE EAST OF THE CWA (DEUEL AND GARDEN COUNTIES) BUT IT WILL BE TOUGH TO ADVECT THIS MOISTURE WESTWARD. THE HRRR MODEL ALONG WITH THE OTHER MODELS DO NOT SHOW ANY QPF OVER THE PANHANDLE TONIGHT SO WILL KEEP SLIGHT CHANE POPS OUT OF THE FCST. WEDNESDAY CONTINUES TO LOOK LIKE A MORE CRITICAL FIRE WEATHER DAY OVER THE REGION. A SHORTWAVE MOVING FROM WASHINGTON INTO MONTANA WILL INDUCE PRESSURE FALLS OVER WESTERN SOUTH DAKOTA WHICH STRENGTHENS THE PRESSURE GRADIENT OVER ESPECIALLY SOUTHEAST WY. MOS GUIDANCE SHOWS WINDS ABOUT 5 KTS HIGHER THAN THIS AFTN ALONG WITH AN ADDITIONAL 5 DEGREES OF WARMING. THE FIRE WEATHER WATCH FOR TOMORROW AFTN INCLUDES TWO ZONES (310 AND 306) THAT ARE NOT INCLUDED IN TODAYS RED FLAG WARNING. THIS LOOKS GOOD SINCE BOTH THESE ZONES WERE CLOSE TO HITTING THE CRITERIA TODAY AND CONDITIONS WILL BE DRIER AND MORE BREEZY TOMORROW. THE DEEP SOUTHWESTERLY FLOW WILL RESULT IN A VERY WARM DAY WITH HIGHS RISING INTO THE UPPER 80S TO MID 90S ACROSS THE PLAINS. THIS COULD BE ONE OF THE WARMEST DAYS FOR THE REST OF THE YEAR SINCE A COLD FRONTAL PASSAGE IS STILL PROGGED FOR THURS MORNING. TEMPS WILL DROP CLOSE TO 20 DEGREES ON THURS. STILL NO GOOD CHANCE OF PRECIP THROUGH AT LEAST THURS EVENING. COULD BE ISOLATED SHOWERS DEVELOPING BY THURS NIGHT ALTHOUGH THE MODEL TREND HAS BEEN TO SHIFT THE MORE WIDESPREAD RAIN WELL TO THE SOUTH OVER NORTHWEST KS. .LONG TERM...(FRIDAY THROUGH MONDAY NIGHT) ISSUED AT 420 PM MDT TUE SEP 2 2014 MODELS ARE IN FAIR AGREEMENT WITH THE MEDIUM RANGE PERIOD SHOWING A PERSISTENT QUASI-ZONAL PATTERN OVER THE CENTRAL CONUS. TEMPERATURES WILL START OFF BELOW AVERAGE ON FRIDAY IN THE POST FRONTAL AIRMASS...WITH THE SFC HIGH SLIDING TO THE SOUTHEAST ACROSS THE CENTRAL PLAINS. SFC WINDS ACROSS THE HIGH PLAINS WILL BE OUT OF THE SOUTHEAST AS THE SFC HIGH SLIDES SOUTHEAST...WITH CONVECTION DEVELOPING OVER THE MOUNTAINS IN THE LATE AFTERNOON IN THIS LLVL UPSLOPE REGIME. SHOULD STAY FAIRLY CAPPED ACROSS THE PLAINS WITHIN THE COOLER AIRMASS...BUT CANT RULE OUT SHOWERS/WEAK TSTORMS MAINTAINING AS THEY MOVE OFF THE MOUNTAINS AS A 70 KT JET AND SHORTWAVE ENERGY WILL BE MOVING OVERHEAD AT THIS TIME. SATURDAY LOOKS VERY SIMILAR ALBEIT WITH WEAKER UPSLOPE FLOW AND SLIGHTLY WARMER TEMPS/HIGH INSTABILITY. SUNDAY AND MONDAY COULD SEE A BIT MORE SUBTROPICAL MOISTURE ADVECT UP FROM THE SOUTHWEST AS A TROUGH DIGS ALONG THE WEST COAST AND MOVES ACROSS THE GREAT BASIN. THE DEEPEST MOISTURE LOOKS TO REMAIN TO OUR SOUTH...BUT CAN SEE SOME OF THIS MOISTURE MAKING IT UP TO SOUTHERN PORTIONS OF THE CWA SO WILL MAINTAIN AT LEAST SLIGHT CHANCE POPS FOR MUCH OF THE CWA. TEMPS WILL INCREASE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR BY MONDAY AS THE UPPER TROUGH DEEPENS AND A WARM AIR ADVECTION PATTERN DEVELOPS OVER THE ROCKIES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON) ISSUED AT 644 PM MDT TUE SEP 2 2014 VFR CONDITIONS TO PREVAIL THRU THE PERIOD. WINDS WILL SUBSIDE AROUND 02Z...BUT BECOME GUSTY AFTER 16Z WEDNESDAY. && .FIRE WEATHER... ISSUED AT 420 PM MDT TUE SEP 2 2014 RELATIVE HUMIDITY VALUES HAVE DROPPED TO AROUND 15 PERCENT THIS AFTERNOON OVER LOWER ELEVATIONS OF SOUTHEAST WYOMING. IN ADDITION...WEST AND SOUTHWEST WINDS HAVE BEEN GUSTING TO 20-30 MPH. A RED FLAG WARNING REMAINS IN EFFECT THROUGH EARLY THIS EVENING OVER PORTIONS OF SOUTHEAST WYOMING. TEMPERATURES WILL WARM ON WEDNESDAY AND WINDS WILL BE MORE BREEZY DURING THE AFTERNOON DUE TO A STRENGTHENING PRESSURE GRADIENT. THUS...EXPECT CRITICAL FIRE WEATHER CONDITIONS TO BE MORE WIDESPREAD OVER SOUTHEAST WYOMING AND FIRE WEATHER WATCHES ARE IN EFFECT. AN ELEVATED FIRE WEATHER THREAT IS PREDICTED OVER THE WESTERN NEBRASKA PANHANDLE DUE TO HUMIDITY VALUES FALLING TO 15-20 PERCENT AND WIND GUSTS OF 20-25 MPH DURING THE AFTERNOON. A COLD FRONT ON THURSDAY MORNING WILL PUSH ACROSS THE AREA WITH MUCH COOLER TEMPERATURES FOR THURSDAY AND INTO THE WEEKEND. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR WYZ301-302-304-306-309-310. RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301-302-304- 309. NE...NONE. && $$ SHORT TERM...FINCH LONG TERM...RJM AVIATION...HAHN FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
425 AM EDT WED SEP 3 2014 ...SCATTERED TO NUMEROUS THUNDERSTORMS TODAY... .CURRENTLY... DEEP LAYER RIDGING HAS SHIFTED A BIT FURTHER W SINCE TUE AFTN AS A MID TO UPPER LEVEL LOW OVER THE SW BAHAMAS IMPINGES ON THE REGION. AN ATLC SFC RIDGE EXTENDS INTO NRN FL AND CENTRAL GULF COAST. DEEP LAYER MOISTURE REMAINS IN PLACE WITH PWATS NEAR 2 INCHES PER 00Z RAOB WITH GPS MET DATA SHOWING SLIGHTLY LOWER VALUES. SFC TEMPS ARE COOLER THAN 24 HRS AGO AND WITH RECENT RAINFALL OVER INLAND AREAS THERE IS A GOOD CHANCE OF SOME PATCHY FOG DEVELOPING THROUGH EARLY MORNING. SOME DEBRIS CLOUDS AOA 20 KFT EXPECTED TO SLOWLY DISSIPATE FROM TUE EVENINGS CONVECTION. LATEST RADAR SHOWS A FEW SHOWERS OFFSHORE FROM 20NM AND BEYOND LIFTING NWD. TODAY...A RELATIVELY SIMILAR ENVIRONMENT TO YESTERDAY WITH ELEVATED MOISTURE LEVELS AND A LIGHT WIND FLOW REGIME ENABLING SEA BREEZES TO BECOME ACTIVE ONCE AGAIN. A FEW SHOWERS AND STORMS OVER THE COASTAL WATERS WILL SLOWLY DIMINISH DURING THE DAY DUE TO THE DEVELOPMENT OF THE E COAST SEA BREEZE. DEEP LAYER FLOW WILL BE WEAK GENERALLY LESS THAN 5 KNOTS...WITH RIDGING HOLDS WHILE MID TO UPPER LOW AND TROUGH OVER CUBA AND SRN FL SLOWLY TREKS WWD. MEAN LAYER WINDS BEGIN TO BECOME ELY BY EARLY EVENING HOURS. THE HRRR MODEL AND GFS SUGGEST ANOTHER EARLY START TO DEVELOPMENT OF SHOWERS AND STORMS...MAINLY ALONG AND NEAR THE E COAST SEA BREEZE AROUND 15Z-17Z...AND THEN FAIRLY STEADY INCREASE IN COVERAGE THROUGH THE AFTN OVER INLAND AREAS. HAVE INCREASED POPS AREA-WIDE TO AROUND 40-60% RANGE WITH SOME HIGH END LIKELY POPS POSSIBLE NEAR THE I-75 CORRIDOR BY LATE AFTN DUE TO INTERACTIONS OF W COAST SEA BREEZE...OUTFLOWS AND E COAST SEA BREEZE. SIMILAR THREATS FROM STORMS FROM YESTERDAY...FREQUENT/EXCESSIVE LIGHTNING...LOCALLY HEAVY RAIN...AND GUSTY WINDS. HIGHS ARE NUDGE DOWNWARD DUE TO SLIGHTLY LOWER 850 MB TEMPS AND INCREASED DEEP CONVECTIVE ACTIVITY...WITH LOWER 90S INLAND AND 88-90 AT THE COAST. TONIGHT...ISOLD TO SCT CONVECTION EXPECTED IN THE EVENING HOURS BEFORE FADING AFTER MIDNIGHT. THE GFS SHOWS A DRY SLOT NW OF THE TROUGH TO OUR S SLIDING UP THROUGH OUR FORECAST AREA BY 12Z THU. THIS WILL ENABLE SOME CLEARING SKIES AND DRY CONDITIONS FILTERING INTO THE AREA. DESPITE THIS...ARW AND NMM MODELS AS WELL AS THE EURO MODEL INDICATE ISOLD TO SCT SHOWERS AND STORMS POSSIBLE OVER THE COASTAL WATERS FROM LOW LEVEL MOISTURE CONVERGENCE. SOME OF THIS ACTIVITY MAY DRIFT INTO THE BEACHES AND INTRACOASTAL WATERWAY NEAR OR BEFORE SUNRISE. PATCHY FOG POSSIBLE WELL INLAND AND LOWS MAINLY LOWER TO MID 70S. THURSDAY...MUCH DRIER CONDITIONS IN THE MID AND UPPER LEVELS WILL SHIFT NWWD OVER THE CWA AND HELP LIMIT CONVECTIVE COVERAGE TO AROUND 20-40% WITH A SLIGHTLY HIGHER CHANCE OVER S ZONES WHERE THERE WILL BE LESS SUBSIDENCE AND MORE MOISTURE AVAILABLE. MEAN FLOW MORE ELY AND INCREASED A FEW KNOTS HELPING TO PUSH THE E COAST SEA BREEZE INLAND MORE QUICKLY THAN TODAY. HIGHS CONTINUE IN THE LOWER 90S MOST LOCATIONS. THURSDAY NIGHT THROUGH FRIDAY NIGHT... DEEP MOISTURE WILL INCREASE FROM SOUTH TO NORTH DURING THIS TIME FRAME AS A WEAKENING TUTT FEATURE MOVES INTO THE SOUTHEASTERN GULF OF MEXICO...AND A WEAK SURFACE REFLECTION SLIDES NORTHWARD UP THE FL PENINSULA. INCREASED NOCTURNAL POPS TO HIGH-END CHANCE OVER THE COASTAL WATERS THURS NIGHT...AND ADDED CHANCE POPS IN THE COASTAL COUNTIES AND NORTH CENTRAL FL ON FRI MORNING AS ENHANCED MOISTURE ADVECTS INTO THESE AREAS. LOWS WILL GENERALLY FALL INTO THE LOWER 70S INLAND...WITH UPPER 70S AT THE COAST. EXPECTING NUMEROUS COVERAGE ALONG THE I-75 CORRIDOR DURING THE AFTERNOON HOURS...WITH DECREASING POPS TOWARDS THE EARLY EVENING HOURS IN THE COASTAL COUNTIES AS THE ATLANTIC SEA BREEZE PUSHES WELL INLAND. INCREASING POPS AND CLOUD COVER SHOULD HOLD HIGHS IN THE UPPER 80S ACROSS MOST OF NORTH CENTRAL AND NE FL...AND NEAR 90 IN SE GA. SOUTHERLY FLOW BEHIND THE WEAK SURFACE WAVE WILL LIKELY PUSH ACTIVITY INTO INTERIOR SE GA DURING THE EVENING HOURS...WHERE ACTIVITY MAY LINGER THROUGH AROUND MIDNIGHT. OTHERWISE...EXPECTING CONVECTION TO AGAIN BLOSSOM OVER THE COASTAL WATERS DURING THE OVERNIGHT HOURS DUE TO DEEPENING SOUTHERLY FLOW. INCREASED MOISTURE AND CLOUD COVER WILL KEEP LOWS IN THE MID 70S INLAND...AND NEAR 80 AT THE COAST. .LONG TERM (SATURDAY THROUGH WEDNESDAY)... FLOW ALOFT WILL TRANSITION TO SOUTHWESTERLY THIS WEEKEND REGION-WIDE AS WEAK TROUGHING ATTEMPTS TO PUSH INTO THE SOUTHEASTERN STATES...WHICH WILL SUPPRESS THE AXIS OF ATLANTIC RIDGING TO A POSITION OVER THE FL PENINSULA. THIS CHANGE IN THE REGIME WILL FOCUS AFTERNOON AND EARLY EVENING CONVECTION CLOSER TO THE I-95 CORRIDOR...WITH SCATTERED TO NUMEROUS COVERAGE EXPECTED THIS WEEKEND. OFFSHORE FLOW SHOULD ALLOW FOR ABOVE NORMAL HIGHS REGION-WIDE...WITH HIGHS CLIMBING INTO THE LOWER 90S AWAY FROM THE IMMEDIATE COAST...WHERE THE GRADIENT SHOULD REMAIN LOOSE ENOUGH FOR AN EARLY AFTERNOON SEA BREEZE TO KEEP HIGHS IN THE UPPER 80S. A RATHER WEAK SURFACE PRESSURE PATTERN WILL PREVAIL FOR THE EARLY AND MIDDLE PORTIONS OF NEXT WEEK...AND PLENTY OF DEEP-LAYERED MOISTURE WILL AID IN THE DEVELOPMENT OF AT LEAST SCATTERED DIURNAL CONVECTION...WITH THE FOCUS SHIFTING BACK TO INLAND LOCATIONS DURING THE AFTERNOON AND EARLY EVENING HOURS. TEMPERATURES WILL REMAIN ABOVE CLIMO DURING THIS TIME FRAME. && .AVIATION...PREVAILING VFR TODAY WITH BRIEF PERIOD OF MVFR VSBY POSSIBLE FOR GNV AND VQQ FROM ABOUT 09Z-11Z. FAVORABLE CONDS FOR SHOWERS AND STORMS AGAIN TODAY WITH FIRST DEVELOPMENT OF A SHOWER OR STORM AROUND 16Z-17Z FOR THE COASTAL TAFS. INCLUDED 3 HR TEMPO GROUP AROUND 17Z-20Z FOR JAX/CRG/VQQ WITH LATER START FOR GNV BY 18Z-19Z. MVFR CONDS IN STORMS WITH GUSTY WINDS AND SHORT PERIOD OF IFR ALSO POSSIBLE IN THE STRONGER STORMS. CONVECTION CHANCES DECREASE BY 22Z OR SO FOR COASTAL TAFS AND AFTER 00Z FOR GNV. && .MARINE...SOUTHEAST TO SOUTH WINDS 10 TO 15 KNOTS WITH SEAS AROUND 2 TO 3 FT. LOCAL SEA BREEZES ALONG THE COAST IN THE AFTERNOONS. GENERAL FLOW REGIME CHANGE LATE IN THE WEEKEND AS SFC RIDGE GRADUALLY SHIFTS SWD INTO CENTRAL FL WHILE A WEAK FRONT MOVES INTO CENTRAL GA...WITH MORE PREVAILING SWLY WINDS SUN. RIP CURRENTS: MAINLY LOW RISK WITH SMALL SWELLS AROUND 1 TO 1.5 FT AND SOUTHEAST SEA BREEZES DURING THE DAYTIME HOURS. && .PRELIMINARY POINT TEMPS/POPS... AMG 93 72 92 71 / 60 30 30 20 SSI 86 76 86 76 / 40 20 20 20 JAX 90 72 90 73 / 50 20 30 20 SGJ 88 74 87 75 / 40 20 30 20 GNV 90 70 91 71 / 60 30 40 30 OCF 90 71 91 72 / 60 30 50 40 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ SHASHY/NELSON
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
216 AM EDT WED SEP 3 2014 .PREV DISCUSSION... /ISSUED 1029 PM EDT TUE SEP 2 2014/ .UPDATE... AFTER AN EARLY START TO CONVECTION OVER THE ATLANTA METRO...FOCUS QUICKLY SHIFTED TO THE SOUTHEAST ZONES WHERE MIDDLE GEORGIA SAW NUMEROUS STRONG TO SEVERE THUNDERSTORMS. THIS ACTIVITY HAS SENT AN OUTFLOW NORTHWARD BACK TO THE METRO BUT NEWLY GENERATED ACTIVITY HAS BEEN HARD TO COME BY. HRRR DOES INDICATE NW ACTIVITY WILL SPREAD EASTWARD AND INTERACT WITH AFOREMENTIONED OUTFLOW BUT REMAINS UNCLEAR IF THIS WILL BE ENOUGH TO GENERATE ADDITIONAL OVERNIGHT THUNDERSTORM ACTIVITY. FOR NOW...HAVE PLAYED IT AS LOW END CHANCE POPS IN THE GRIDS FOR MOST LOCATIONS...EXCEPT NORTHWEST WHERE I HAVE GONE SLIGHTLY HIGHER GIVEN ADDED DYNAMICS IN PLAY. OTHERWISE FORECAST IS IN GOOD SHAPE AND NO CHANGES ARE PLANNED. DEESE && PREV DISCUSSION... /ISSUED 817 PM EDT TUE SEP 2 2014/ PREV DISCUSSION... /ISSUED 301 PM EDT TUE SEP 2 2014/ .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... WEAK IMPULSE IN THE FLOW PUSHING ACROSS THE EASTERN CONUS TODAY AND THIS MAY HELP THE SHOWERS AND THUNDERSTORMS ACROSS NORTH GEORGIA CONTINUE INTO TONIGHT. AFTER THIS THOUGH...NO SIGNIFICANT FEATURE AT THE UPPER LEVELS TO KEY IN ON IN THE SHORT TERM. BASICALLY WILL CONTINUE AGAIN TOMORROW WITH THE DIURNALLY DRIVEN THUNDERSTORMS IN THE AFTERNOON AND EVENING. WITH MUCAPE VALUES OVER 2000 J/KG WEDNESDAY AFTERNOON...STRONG TO ISOLATED SEVERE STORMS WILL BE POSSIBLE. THE MAIN THREATS TOMORROW AFTERNOON APPEAR TO BE GUSTY WINDS AND LOCALLY HEAVY RAINFALL. FAIRLY BIG DISCREPANCIES IN THE TEMPERATURE GUIDANCE FOR TOMORROW WITH THE MAV BEING WARMER THAN THE MET. AT ATL...THERE IS A SIX DEGREE TEMPERATURE DIFFERENCE BETWEEN THESE TWO FOR HIGHS TOMORROW AFTERNOON. MUCH OF THIS IS CAUSED BY MORE CLOUD COVERAGE DEPICTED BY THE NAM. THINK THE NAM IS OVERDOING CLOUD COVERAGE THOUGH SO STARTED WITH A BLEND...AND THEN LEANED TOWARDS THE WARMER SIDE FOR HIGH TEMPS TOMORROW. ONCE AGAIN BOTH HIGH AND LOW TEMPERATURES WILL BE ABOVE NORMAL. 11 && .LONG TERM /THURSDAY THROUGH TUESDAY/... NO CHANGES TO THE CURRENT LONG TERM. SEE PREVIOUS DISCUSSION BELOW... 17 LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... /ISSUED 325 AM EDT TUE SEP 2 2014/ SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EXPECTED EACH DAY THROUGH THE LONG TERM. WEAK TROUGH STILL IN PLACE ACROSS CENTRAL GA WEDNESDAY NIGHT...BUT WILL EVENTUALLY DISSIPATE ON THURSDAY. ALOFT...A WEAK SHEAR AXIS WILL REMAIN THROUGH FRIDAY. THE DISSIPATING BOUNDARY AND SHEAR AXIS ALOFT MAY SERVE TO FOCUS ANY CONVECTION THURSDAY INTO FRIDAY. A WEAK FRONT IS STILL ON TRACK FOR THE MID TO LATE WEEKEND. WITH SUCCESSIVE RUNS...THE MODELS HAVE SLOWED THE SOUTHWARD PROGRESS OF THE BOUNDARY. CURRENTLY...THE FRONT SHOULD MOVE ACROSS NORTHERN GA LATE SATURDAY/EARLY SUNDAY THEN STALL ACROSS CENTRAL GA BY LATE SUNDAY/EARLY MONDAY. THE FRONT LOOKS TO BECOME DIFFUSE BY TUESDAY. TEMPS STILL EXPECTED TO BE ABOVE NORMAL THROUGH THE PERIOD. NLISTEMAA && .AVIATION... 06Z UPDATE... MAINLY VFR CONDITIONS THOUGH CHANCE FOR MORNING MVFR VSBYS AT SOME SITES. CIGS GENERALLY NEAR 12 KFT THIS MORNING WITH SOME SCT NEAR 5 KFT. AFTERNOON CU FIELD LIKELY IN 4-5 KFT RANGE ALONG WITH DECENT TSRA POTENTIAL AFTER 18-19Z. WINDS GENERALLY LIGHT AND VRB TO CALM INITIALLY BECOMING NW TO W UNDER 7 KTS TODAY. VRB GUSTS AND REDUCED VSBYS AGAIN POSSIBLE WITH ANY STORM DEVELOPMENT. //ATL CONFIDENCE...06Z UPDATE... MEDIUM IN PRECIP TIMING. HIGH ALL ELSE. BAKER && .PRELIMINARY POINT TEMPS/POPS... ATHENS 95 71 92 69 / 40 30 40 30 ATLANTA 90 73 88 70 / 40 40 40 30 BLAIRSVILLE 86 66 84 63 / 40 30 40 30 CARTERSVILLE 91 69 90 68 / 30 30 40 30 COLUMBUS 94 74 90 71 / 40 40 30 20 GAINESVILLE 90 72 89 69 / 40 30 40 30 MACON 94 71 92 69 / 40 40 30 20 ROME 92 69 91 68 / 30 30 40 30 PEACHTREE CITY 90 70 88 68 / 40 40 40 30 VIDALIA 95 73 92 71 / 40 30 30 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...11/DEESE LONG TERM...NLISTEMAA/17 AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
135 AM EDT WED SEP 3 2014 .SYNOPSIS... ISSUED AT 130 AM EDT TUE SEP 2 2014 WITH HIGH PRESSURE OVER THE REGION...SKIES WILL BE MOSTLY CLEAR AND LOW TEMPERATURES WILL DROP INTO THE 50S OVERNIGHT. THERE WILL BE AREAS OF FOG WITH PATCHY DENSE FOG IN LOW LYING AREAS AND NEAR BODIES OF WATER. ONCE THE FOG BURNS OFF ON WEDNESDAY A BEAUTIFUL EARLY SEPTEMBER DAY WILL BE IN STORE WITH HIGHS IN THE MIDDLE 80S ALONG WITH LOWER HUMIDITY. && .UPDATE... ISSUED AT 656 PM EDT TUE SEP 2 2014 FORECAST STILL ON TRACK NEXT COUPLE OF HOURS AS SEVERAL BOUNDARIES (OUTFLOW AND LAKE BREEZE) WERE DRIFTING SOUTH ACROSS N INDIANA AND NW OHIO. ISOLATED SHOWERS HAVE POPPED HERE AND THERE AND EVEN A STRAY LIGHTNING STRIKE A FEW HOURS AGO. TRENDS SHOULD CONTINUE DOWNWARD WITH LOSS OF HEATING AND EVENTUAL TRANSLATION OF BOUNDARIES OUT OF THE AREA. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 344 PM EDT TUE SEP 2 2014 INFILTRATION OF DRIER AIR INTO THE REGION HAS BEEN SLOW THIS AFTERNOON...WITH AMPLE BOUNDARY LAYER MOISTURE AMID WASHED OUT SURFACE BOUNDARY ACROSS THE FORECAST AREA. LOW CLOUDS HAVE BEEN SLOW TO MIX OUT THROUGH EARLY AFTERNOON BUT LATEST SAT TRENDS SHOWING MORE SCT LOW LVL CLOUD LAYER...ESPECIALLY NW. ISOLD SHOWERS CURRENTLY NOTED ON RADAR ACROSS NW/NC IN...GIVEN AMPLE BOUNDARY LAYER MOISTURE...WEAK SFC CONVERGENCE AND SFC HEATING YIELDING VERY MODEST SB CAPES UP TO 1000 J/KG ACROSS THE REGION. HRRR AND EVEN NAM12 HINTING AT ISOLD SHOWER ACTIVITY SPREADING EAST ACROSS THE FORECAST AREA THROUGH SUNSET. THEREFORE HAVE KEPT AN ISOLD SHOWER MENTION THROUGH 00Z IN THE FCST. LOW CONFIDENCE FOR THUNDER AT THIS TIME GIVEN LACK OF FORCING AND WEAK MID LVL LAPSE RATES. AS RIDGING BUILDS EASTWARD INTO THE OVERNIGHT HOURS...CLEARING SKIES AND DRY CONDITIONS EXPECTED. WITH SLACKENING GRADIENT AND LOW LVL MOISTURE...ESPECIALLY SE W/ THE PRECIP OVER THE PAST 24 HRS...FOG DEVELOPMENT LOOKS LIKELY LATE IN THE OVERNIGHT INTO DAYBREAK WEDNESDAY. KEPT PREVIOUS FCST IN TACT WITH AREAS OF FOG MENTION FROM 09-12Z. LOW CONFIDENCE WITH THE POSSIBILITY OF DENSE FOG AT THIS TIME...GIVEN LOW LEVEL DRY ADVECTION AND EXTENSIVE CIRRUS SHIELD NOTED ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA THIS AFTERNOON. IF CLOUD COVER IS QUICK TO DIMINISH TONIGHT...W/ LACK OF ANY CONVECTIVE DEBRIS...THEN DENSE FOG CHANCES WOULD INCREASE TOWARD TOMORROW MORNING...ESPECIALLY SE. WILL MONITOR TRENDS THROUGH THE EVENING AND WILL UPDATE AS NECESSARY. RIDGING BUILDS EAST OF THE AREA THROUGH THE DAY ON WEDNESDAY...WITH MOSTLY SUNNY SKIES AND FAIR CONDITIONS. KEPT HIGH TEMPS SLIGHTLY BELOW MAV...ALTHOUGH UPWARD ADJUSTMENT MAY BE NEEDED IN THE NEXT FCST WITH WAA INTO THE AREA BY THE AFTERNOON HOURS ON THE WESTERN PERIPHERY OF THE RIDGE. && .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 344 PM EDT TUE SEP 2 2014 THE GFS AND ECMWF HAVE APPEARED TO INITIALIZE THE UPSTREAM SHORT WAVE WELL AND ALSO SEEM HAVE A REASONABLE TRACK WITH THIS SYSTEM ACROSS THE CONUS THIS WEEK. THE ECMWF AND GFS HAVE ALSO SHOWN GOOD CONSISTENCY FROM RUN TO RUN WITH THIS SYSTEM THE PAST SEVERAL RUNS. LOW LEVEL THETA E AND MOISTURE FLUX WILL INCREASE RAPIDLY WEDNESDAY NIGHT...ESPECIALLY NORTH AND NORTHWEST OF THE AREA. HAVE ADDED A SMALL CHANCE FOR THUNDERSTORMS OVERNIGHT WEDNESDAY NIGHT ON THE LEADING EDGE OF THIS THETA E ADVECTION OVER FAR NORTHWEST AREAS... ESPECIALLY BERRIEN AND LAPORTE COUNTY. KEPT THURSDAY DRY AS THE PRIMARY LOW LEVEL FORCING SHIFTS NORTH OF THE AREA AND AS A LOW LEVEL INVERSION INCREASES AT THE BASE OF A WEAK TO MODERATE ELEVATED MIXED LAYER. THE GFS MAV/MEX TEMPERATURES HAVE BEEN CONSISTENT AT GENERALLY 5 TO 10 DEGREES ABOVE NORMAL FOR THURSDAY AND FRIDAY AND APPEAR ON TRACK WITH 850 MB TEMPERATURES APPROACHING 20C. THUNDERSTORM CHANCES LOOK BEST OVERNIGHT THURSDAY NIGHT THROUGH FRIDAY NIGHT AS A COLD FRONT APPROACHES. GIVEN THE TIMING OF THE FRONT AND SUBSTANTIAL INSTABILITY BY LATE THURSDAY AND FRIDAY AFTERNOON/EARLY EVENING WITH CAPES AS HIGH AS 2000 TO 3000 J/KG...CONCERN FOR AN UPSTREAM CONVECTIVE COMPLEX TO DROP SOUTHEAST OR SOUTH INTO THE FORECAST AREA AS RICH THETA E SPREADS OVER THE AREA. EXPANDED THUNDERSTORM CHANCES THURSDAY NIGHT IN THIS REGARD. OTHERWISE...KEPT STORM CHANCES FRIDAY AND FRIDAY NIGHT. OTHERWISE... COOLER AND DRIER CONDITIONS CAN BE EXPECTED FOR THE WEEKEND INTO NEXT WEEK WITH HIGHS IN THE 70S THROUGH TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 130 AM EDT WED SEP 3 2014 A WEAK SHORT WAVE PASSING THROUGH THE REGION WAS GENERATING SOME MID LEVEL CLOUDS. THESE SHOULD BE SHORT LIVED WITH VFR TO START THE TAF PERIOD. LIGHT WINDS AND MOSTLY CLEAR SKIES WILL ALSO ALLOW BR TO FORM. HAVE ALREADY SEEN SOME PATCHY MVFR AND IFR IN RURAL AREAS. STILL EXPECT KFWA TO HAVE BEST CHANCE OF SEEING MVFR AND IFR CONDITIONS OVERNIGHT. FOG SHOULD BURN OFF QUICKLY AFTER SUNRISE WITH VFR AND SOUTH TO SOUTHWEST WINDS UNDER 10 KNOTS EXPECTED REMAINDER OF PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...FISHER SYNOPSIS...LASHLEY SHORT TERM...NG LONG TERM...SKIPPER AVIATION...LASHLEY VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
103 AM CDT WED SEP 3 2014 ...UPDATED AVIATION SECTION... .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 344 PM CDT TUE SEP 2 2014 THE MID TO UPPER LEVEL FLOW HAS BECOME ZONAL IN THE WAKE OF THE MINOR SHORTWAVE TROUGH THAT TRAVERSED THE CENTRAL PLAINS MONDAY EVENING. THE EFFECTIVE FRONTAL BOUNDARY AFTER ALL OF THE NIGHTTIME CONVECTION WAS SITUATED ACROSS CENTRAL OKLAHOMA AND SOUTHERN ARKANSAS. SOUTH OF THIS FRONT, TEMPERATURES WERE ABOVE 90 AS OF 2 PM, BUT ON THE COOL SIDE OF THE FRONT, MOST READINGS WERE IN THE 70S TO LOWER 80S. LEE TROUGHING WILL DEVELOP TONIGHT AND WEDNESDAY IN RESPONSE TO THE ZONAL FLOW. LATE TONIGHT, WARMER MID LEVEL TEMPERATURES WILL SPREAD ACROSS SOUTHWEST KANSAS, CAPPING THE ELEVATED MOIST LAYER. THE NAM INDICATES THAT LOW LEVEL WINDS WILL BECOME SOUTHERLY AS THE WARM FRONT SHIFTS INTO NORTHERN KANSAS BY WEDNESDAY MORNING. HOWEVER, THE RAP SHOWS THE BOUNDARY STILL SITUATED ALONG THE KANSAS/OKLAHOMA BORDER AT 12Z. SINCE WE MAY MAINTAIN UPSLOPE SOUTHEASTERLY FLOW MOST OF THE NIGHT, I OPTED TO BRING THE LOW CLOUDS AND FOG BACK IN TOWARD 09Z. A MID LEVEL CLOUD DECK MAY DEVELOP AS THE LOW LEVEL JET DEVELOPS THIS EVENING AND AN ELEVATED THUNDERSTORM OR TWO CAN`T BE COMPLETELY RULED OUT OVER SOUTH CENTRAL KANSAS BEFORE THE STRONG CAPPING INVERSION DEVELOPS. ON WEDNESDAY, THE LEE TROUGH WILL BECOME ESTABLISHED ACROSS THE HIGH PLAINS, WITH A WEAK SURFACE DRYLINE SITUATED ACROSS FAR WESTERN KANSAS. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT LATE IN THE DAY. HIGH TEMPERATURES WILL BE IN THE MID TO HIGH 90S,WITH SOME READINGS CLOSE TO 100F. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 357 PM CDT TUE SEP 2 2014 A STRONG UPPER LEVEL SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE EASTWARD INTO THE NORTHERN PLAINS AND UPPER MIDWEST BY FRIDAY. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS WESTERN KANSAS AND THE CENTRAL PLAINS ON THURSDAY BRINGING THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS. THE STRONGEST MID AND UPPER LEVEL WINDS WILL BE IN NEBRASKA, SO NOT EXPECTING LOTS OF SEVERE WITH THE FRONT. CAPE VALUES AROUND 2000 J/KG WILL BE SUFFICIENT TO PRODUCE SOME SMALL HAIL AND STRONG WINDS AS THE COLD FRONT SWEEPS ACROSS WESTERN KANSAS TO NEAR DODGE CITY BY 7 PM THURSDAY AND THROUGH MEDICINE LODGE BY AROUND MIDNIGHT. HIGH TEMPERATURES WILL BE VERY WARM AHEAD OF THE COLD FRONT ON THURSDAY WITH LOW TO MID AND UPPER 90S FORECAST. HIGHS THEN COOL INTO THE 70S INTO FRIDAY WITH A CONTINUED CHANCE FOR MAINLY AFTERNOON THUNDERSTORMS BEHIND THE FRONT IN MOIST SURFACE UPSLOPE FLOW. BY MONDAY HIGHS WARM BACK INTO THE 80S AS THE COOL HIGH PRESSURE AREA MOVES EAST AND WARM SOUTHERLY WINDS INCREASE. MORE THUNDERSTORM CHANCES CONTINUE INTO TUESDAY WITH DISTURBANCES IN SOUTHWEST FLOW ALOFT AND UPPER JET. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1259 AM CDT WED SEP 3 2014 THE AVIATION FORECAST THROUGH 12-15Z TIME FRAME WEDNESDAY WILL BE CHALLENGING. WE WILL MAINTAIN THE PESSIMISTIC FORECAST OF CEILING FALLING TO AROUND 200-300 FEET AT GCK AND DDC STARTING AROUND 10Z. THE LIFR CONDITIONS SHOULD EXIST FOR AT LEAST A COUPLE HOURS BEFORE DRIER AIR MOVES IN FROM THE SOUTHWEST AS LOW LEVEL SOUTHWEST MOMENTUM INCREASES BY DAYBREAK. FOR NOW, WE WILL KEEP HYS AWAY FROM THE IFR/LIFR CONDITIONS, BUT THIS IS ALSO A LOW CONFIDENCE FORECAST WITH AMENDMENTS QUITE POSSIBLE. SOUTHWEST WINDS WILL INCREASE DURING THE LATE MORNING THROUGH MIDDAY TIME FRAME, GUSTING TO 30+ KNOTS BY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... DDC 72 95 64 78 / 0 10 40 40 GCK 70 92 61 76 / 0 20 40 40 EHA 68 94 63 79 / 10 10 60 30 LBL 71 96 66 81 / 10 0 40 40 HYS 72 92 61 72 / 10 20 50 40 P28 74 97 70 83 / 10 0 30 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...FINCH LONG TERM...KRUSE AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS JACKSON KY
151 AM EDT WED SEP 3 2014 .UPDATE... ISSUED AT 1020 PM EDT TUE SEP 2 2014 01Z SFC ANALYSIS SHOWS WAKE HIGH PRESSURE OVER MUCH OF EAST KENTUCKY TRAILING THE LINEAR MCS THAT PASSED THROUGH DURING THE EVENING WITH STRONG TO SEVERE STORMS THAT PRODUCED MAINLY DAMAGING WIND GUSTS. THIS SYSTEM HAS ESSENTIALLY WASHED OUT THE FRONT AND PUSHED IT MAINLY SOUTH AND EAST OF KENTUCKY. HOWEVER...THERE WILL STILL BE SOME SCATTERED SHOWERS AND PERHAPS A STRAY STORM AROUND THE FAR SOUTHEAST PORTION OF THE CWA INTO THE NIGHT. THE CLOUDS WILL GRADUALLY THIN AND CLEAR OVERNIGHT AND THIS WILL LIKELY SET THE STAGE FOR FOG FORMATION...BECOMING LOCALLY DENSE IN THE VALLEYS BY DAWN. HAVE INCLUDED THIS ALL IN THE GRIDS WITH THIS UPDATE. ALSO FINE TUNED THE TEMPS AND DEW POINTS THROUGH MORNING PER THE LATEST OBS...TRENDS...AND GUIDANCE FROM THE CONSSHORT. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. A FRESHENED SET OF ZONES AND HWO HAVE BEEN SENT. UPDATE ISSUED AT 758 PM EDT TUE SEP 2 2014 THE MAIN LINE OF STORMS IS FINALLY MOVING INTO THE NEIGHBORING STATES. A SECONDARY TROUGH IS MOVING THROUGH THE BLUEGRASS AND APPEARS TO BE FALLING APART. THIS SYSTEM WILL CONTINUE TO MOVE TO THE SOUTH AND EAST AND WILL BE OUT OF THE AREA BY MORNING. HAD TO LOWER THE TEMPERATURES AS THEY DROPPED DOWN MUCH LOWER THAN EXPECTED AS THE LINE WENT THROUGH THE AREA. EXPECT FOG TO BE FORMING AS THE SYSTEM MOVES OUT. IT WILL BE PATCHY...BUT MAINLY DENSE. SOME ISOLATED SHOWERS MAY DEVELOP BEHIND THE MAIN SYSTEM TONIGHT...SO DID NOT IMMEDIATELY END THE PRECIPITATION CHANCES. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 343 PM EDT TUE SEP 2 2014 A LINE OF THUNDERSTORMS WITH HEAVY RAINS HAS FORMED ALONG AN OLD OUTFLOW BOUNDARY ACROSS THE MID SECTION OF EASTERN KENTUCKY. SOME OF THE STORMS HAVE BECOME NEAR SEVERE AND EXPECT SOME SEVERE STORM WARNINGS TO BE ISSUED DURING THE NEXT FEW HOURS. THE MAIN THREAT WILL BE WIND GUSTS. ANOTHER CONCERN IS THAT WITH UNIDIRECTIONAL FLOW AND HIGH PRECIPITABLE WATER...FLOODING CONCERNS WILL BE A REAL ISSUE THIS AFTERNOON AND EVENING...MAINLY IN THE SOUTHERN HALF OF EASTERN KENTUCKY AND ESPECIALLY ALONG THE OLD OUTFLOW BOUNDARY. EXPECT THE FRONT TO PUSH THE PRECIPITATION SOUTH OF THE AREA BY WEDNESDAY MORNING. IN GENERAL...THE HRRR AND RAP HAVE NOT BEEN DOING TOO WELL WITH THIS SYSTEM SO FAR. WEDNESDAY FIGURES TO BE A LITTLE MORE COMFORTABLE AS THE HUMIDITY WILL BE A LITTLE LOWER. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 301 PM EDT TUE SEP 2 2014 THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE FRONT FINALLY MOVES OUT OF THE AREA. TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 151 AM EDT WED SEP 3 2014 CONDITIONS VARIED WIDELY AT TAF ISSUANCE FROM VLIFR TO VFR. AS MID/HIGH CLOUDS DECREASE DURING THE NIGHT...WILL EXPECT FOG AND LOW CLOUDS TO BECOME MORE EXTENSIVE...WITH MOST PLACES SETTLING TO IFR OR WORSE BY DAWN. SLOW IMPROVEMENT IS FORECAST DURING THE DAY ON WEDNESDAY...WITH VFR FINALLY RETURNING DURING THE AFTERNOON. SCATTERED SHOWERS SHOULD ALSO DEVELOP IN THE AFTERNOON...MAINLY NEAR AND SOUTH OF A LINE FROM SOMERSET TO PIKEVILLE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JJ LONG TERM...AR AVIATION...HAL
AREA FORECAST DISCUSSION
NWS HASTINGS NE
418 AM CDT WED SEP 3 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 417 AM CDT WED SEP 3 2014 UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER 70S. THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT /THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER OF THE CWA. TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN MILD IN THE MID 60S TO MID 70S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 417 AM CDT WED SEP 3 2014 MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION. WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES. AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED STATES. MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING THE COLD FRONT FARTHER SOUTH. INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY LATE EVENING FRIDAY NIGHT INTO SATURDAY. THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A WARM FRONT. ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME COOLER WEATHER FOR WEDNESDAY. THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN RIGHT NOW. FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE DAY AFTER A COLD FRONT PASSAGE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1224 AM CDT WED SEP 3 2014 PRIMARY CONCERN FOR THIS TAF PERIOD COMES THROUGH THE AT LEAST MIDMORNING...WITH MODELS STILL SHOWING THE POTENTIAL FOR FOG/STRATUS DEVELOPMENT AS MOISTURE CONTINUES TO ADVECT INTO THE AREA FROM THE SOUTH. IF MODEL TRENDS PAN OUT...CONDITIONS SHOULD IMPROVE AS WE GET TOWARD MIDDAY...WITH VFR CONDITIONS FOLLOWING. NO NOTABLE CHANGES IN WINDS ARE EXPECTED...REMAINING SOUTHERLY...THOUGH WILL BECOME MORE GUSTY THIS AFTERNOON. SPEEDS OF 15 TO 20 MPH AND GUSTS NEAR 25 MPH ARE EXPECTED. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADO LONG TERM...HEINLEIN AVIATION...ADO
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
126 AM EDT WED SEP 3 2014 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL PUSH ACROSS THE NORTH COUNTRY THROUGH THE EVENING HOURS AHEAD OF A COLD FRONT. EXPECT LOCALLY HEAVY DOWNPOURS AND GUSTY WINDS WITH THE STRONGER STORMS. SUNNY, DRY AND COOLER WEATHER WILL LAST INTO THURSDAY. WARM SUMMER WEATHER RETURNS FRIDAY BUT WILL BE SHORT LIVED AS ANOTHER COLD FRONT SWEEPS IN EARLY SATURDAY GIVING A TASTE OF FALL-LIKE WEATHER FOR SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... AS OF 1044 PM EDT TUESDAY...COLD FRONT CONTINUES TO MAKE ITS WAY EASTWARD ACROSS VERMONT LATE THIS EVENING...AND WILL EXIT THE FORECAST AREA BETWEEN 05Z-06Z. HEAVIEST PRECIPITATION WITH SOME EMBEDDED THUNDER ALONG THE COLD FRONT...WITH POST FRONTAL RAINS ACROSS REST OF VERMONT AND NORTHEAST NEW YORK ASSOCIATED WITH TRAILING MID LEVEL SHORTWAVE. MAIN THREAT THIS EVENING HAS BEEN HEAVY RAINFALL. HOWEVER...RAINFALL RATES IN HEAVIER PRECIPITATION HAVE DECREASED ENOUGH SO THAT THREAT OF FLASH FLOODING HAS DIMINISHED. HAVE MADE SOME MINOR ADJUSTMENTS TO FORECAST WITH LATEST UPDATE TO ACCOUNT FOR LATEST OBSERVATIONAL DATA AND TRENDS. EARLIER DISCUSSION... WELL, THE ATMOSPHERE IS FAIRLY PRIMED. VERY WARM AND HUMID AIRMASS IS RESULTING IN MODEST SURFACE BASED INSTABILITY (CAPE PUSHING 2000 J/KG AND LIFTED INDEX OF -2 TO -4C). SO FAR THE ACTIVITY HAS BEEN SPARSE ACROSS THE FORECAST AREA, HOWEVER RADAR SHOWS THE BUILDING LINE OF SHOWERS AND THUNDERSTORMS OUT ACROSS ONTARIO. THESE STORMS SHOULD BE CROSSING INTO THE UNITED STATES IN THE NEXT COUPLE OF HOURS. STILL LIKE HOW THE HRRR AND OUR LOCAL 6KM WRF ARE HANDLING THE EVOLUTION OF THE CONVECTION. STILL LOOKS LIKE AN ETA INTO THE CHAMPLAIN VALLEY DURING THE EVENING (LET`S GO WITH 6-8PM) AND THEN INTO EASTERN VERMONT BY 10PM. UPPER LEVEL SHORTWAVE WHICH IS THE PRIMARY TRIGGER FOR THE CONVECTION IS NOW OVER MICHIGAN AND STARTING TO LIFT NORTHEAST. OUT AHEAD OF THAT SHORT WAVE THE WIND FIELDS AND RELATED SHEAR INCREASE, BUT AT THE SAME TIME WE ARE GETTING CLOSER TO SUNSET AND LOSS OF HEATING. SO IT`S A BATTLE BETWEEN TIMING OF THE BEST DYNAMICS VS BEST INSTABILITY. AT THIS POINT STILL SEE NOTHING TO CHANGE THE IDEA THAT WE`LL HAVE AT LEAST A FEW STRONG T-STORMS AROUND, ESPECIALLY THIS EVENING AND MAINLY WEST OF THE GREEN MOUNTAINS. HAVE MAINTAINED THE IDEA OF GUSTY WINDS AND HEAVY RAIN AS THE PRIMARY THREATS. THE ACTIVITY WINDS DOWN BY MID EVENING IN THE ST LAWRENCE VALLEY TO JUST AFTER MIDNIGHT IN EASTERN VERMONT. DEPENDING ON HOW MUCH CLEARING WE GET, WE COULD HAVE A BIT OF PATCHY FOG LATE TONIGHT. THE COOLER AIR LAGS THE WEATHER A BIT, SO IT WILL STILL BE A MUGGY NIGHT WITH LOWS IN THE 60S. && .SHORT TERM /8 AM THIS MORNING THROUGH THURSDAY NIGHT/... AS OF 355 PM EDT TUESDAY...IT WILL BE A QUIET 48 HOURS. SHORT TERM MODELS IN PRETTY GOOD AGREEMENT WITH REGARD TO RIDGING OVER THE REGION. DAILY SPECIFICS... WEDNESDAY: FLOW TURNS NORTHWEST DURING THE MORNING. 850MB TEMPERATURES FALL TO 11-12C WHICH WILL SUPPORT HIGH TEMPERATURES IN THE MID-UPPER 70S. WITH SOME WEAK COLD-AIR ADVECTION AND A GOOD DEAL OF SUN, WE`LL HAVE SOME EXCELLENT MIXING DURING THE AFTERNOON. WE SHOULD BE ABLE TO TAP SOME OF THE 20KT OR SO OF WIND THAT WILL BE A FEW THOUSAND FEET UP, SO IT SHOULD GET A LITTLE BREEZY IN THE AFTERNOON. WEDNESDAY NIGHT: HIGH PRESSURE OVERHEAD. CLEAR AND CALM, SO PATCHY FOG LOOKS LIKE A GOOD BET, ESPECIALLY SINCE THE GROUND WILL STILL BE A BIT DAMP FROM THE RAIN THIS EVENING. TEMPERATURES MAINLY IN THE 50S, THOUGH UPPER 40S POSSIBLE IN COLD SPOTS LIKE SARANAC LAKE. THURSDAY: SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE STILL NEARLY OVERHEAD, BUT STARTING TO PUSH EAST OF THE AREA. 850MB TEMPERATURES UP TO 12-13C, WHICH SUPPORTS UPPER 70S TO LOW 80S FOR HIGHS. PLENTY OF SUN AS WELL. THURSDAY NIGHT: DISCARDED THE NAM AS IT SEEMS TOO AGRESSIVE WITH THE LEADING EDGE OF WARM AIR ADVECTION AND PRODUCES THICKENING CLOUDS AND EVEN SOME LIGHT SHOWERS. THINK IT WILL REMAIN MOSTLY CLEAR AND DRY PER OTHER MODELS. HOWEVER WITH SOUTHWEST FLOW DEVELOPING, IT WON`T BE AS COLD, LOTS OF 50S AND EVEN LOW 60S FOR LOWS. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 350 PM EDT TUESDAY...EXTENDED PERIOD REMAINS PREDOMINATELY QUIET...LARGELY DOMINATED BY HIGH PRESSURE STARTING THE LATTER PART OF THE WEEKEND...BUT WET TO BEGIN. FOR THE START OF THE PERIOD...RISING HEIGHTS AND WARMING TEMPERATURES CONTINUE FRIDAY AS AN UPPER RIDGE CRESTS OVER THE NORTHEAST IN ADVANCE OF OUR NEXT SURFACE FRONT. MEAN 925MB TEMPS OF +20-23C WILL SUPPORT HIGHS WELL ABOVE NORMAL FOR EARLY SEPTEMBER WITH WIDESPREAD 80`S EXPECTED. IT`LL BE MUGGY TOO WITH DEWPOINTS RANGING THROUGH THE 60S WHICH WILL CREATE AMPLE SURFACE INSTABILITY TO SUPPORT SHOWER AND THUNDERSTORM DEVELOPMENT ALONG/AHEAD OF THE AFOREMENTIONED FRONT WHICH WILL SHIFT INTO THE BTV CWA LATE IN THE DAY AND THROUGH THE EVENING. STILL LOOKS LIKE THE BEST UPPER DYNAMICS PASSES TO OUR NORTH...WITH THE SURFACE BOUNDARY PARALLEL WITH UPPER FLOW SUPPORTING THE IDEA OF A SLOW EASTWARD PROGRESSION WHICH IS MAINTAINED BY THE LATEST ECMWF. GFS REMAINS A BIT FASTER PUSHING THE BOUNDARY THROUGH THE CWA BY SATURDAY MORNING SO HAVE CONTINUED ON WITH THE PREVIOUS FORECAST THINKING LEANING TOWARDS THE ECMWF. BY LATE SATURDAY TREND WILL BE TOWARDS CLEARER AND DRIER WEATHER AS THE UPPER FLOW TURNS ZONAL AND SURFACE HIGH PRESSURE BUILDS EASTWARD OUT OF THE CENTRAL CONUS. THIS HIGH THEN SLOWLY SHIFTS EAST THROUGH THE NORTHEAST AND OFF INTO THE CANADIAN MARITIMES BY LATE TUESDAY OFFERING A NICE STRETCH OF LATE SUMMER WEATHER. TEMPS RETURN TO MORE SEASONABLE LEVELS TO MAYBE SLIGHTLY BELOW NORMAL WITH EXPECTED HIGHS SATURDAY THROUGH TUESDAY IN THE UPPER 60S TO LOW 70S...AND LOWS IN THE MID 40S TO LOW 50S. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... THROUGH 06Z THURSDAY...BULK OF THE RAINFALL HAS MOVED EAST OUT OF VERMONT AND ALL TAF SITES FORECASTS ARE RAIN FREE. LIFR CEILINGS AT KMSS KSLK KMPV EXPECTED TO CONTINUE OVERNIGHT. VFR CIGS ELSEWHERE THROUGH 12Z THEN CONDITIONS IMPROVE TO VFR CLR. QUITE A BIT OF VARIABILITY WITH CLOUD COVER ACROSS THE AREA...AND EXPECT TO BE CHASING OBS WITH AMENDMENTS THROUGH MORNING HOURS AS CIGS VARY UP AND DOWN IN THE LIFR LOCATIONS. DID NOT HIT VIS TOO HARD DESPITE OVERNIGHT RAINFALL...THINKING CLOUD COVER WILL INHIBIT RADIATIONAL COOLING AND FOG FORMATION. LIGHT WEST TO NW WIND THROUGH THE FORECAST PERIOD. OUTLOOK 00Z THURSDAY THROUGH SUNDAY... 06Z THU - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK. 00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS AND THUNDERSTORMS. 00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...NASH NEAR TERM...RJS/NASH SHORT TERM...NASH LONG TERM...LAHIFF AVIATION...HANSON
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 AM EDT WED SEP 3 2014 .SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 305 AM WEDNESDAY... A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING. LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT. HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE MAIN STORM THREATS. CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AS OF 305 AM WEDNESDAY... THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN THE UPPER 60S AND LOWER 70S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY... THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK. A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM WATERS. FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS... BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO) H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE 80S. SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH HIGHS IN THE UPPER 70S TO LOWER 80S. TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 150 AM WEDNESDAY... A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z. MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS. HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS TIME. ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING. OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE THIS WEEKEND INTO EARLY NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BSD/WSS NEAR TERM...BLS SHORT TERM...BLS LONG TERM...MWS AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT WED SEP 3 2014 .SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 305 AM WEDNESDAY... A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING. LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT. HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE MAIN STORM THREATS. CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AS OF 305 AM WEDNESDAY... THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN THE UPPER 60S AND LOWER 70S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 255 PM TUESDAY... FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT... PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL. FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC... ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING. WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING OVER THE CAROLINAS. -GIH && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 150 AM WEDNESDAY... A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z. MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS. HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS TIME. ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING. OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE THIS WEEKEND INTO EARLY NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BSD/WSS NEAR TERM...BLS SHORT TERM...BLS LONG TERM...HARTFIELD AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 AM EDT WED SEP 3 2014 .SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM TUESDAY... CONVECTION HAS LARGELY DISSIPATED ACROSS THE AREA THIS EVENING WITH NOCTURNAL STABILIZATION TAKING HOLD. HOWEVER... AN APPROACHING LINE OF SHOWERS AND STORMS... CURRENTLY MOVING EAST-SOUTHEASTWARD THROUGH THE NC AND VA MOUNTAINS... IN ADVANCE OF A WEAK COLD FRONT IS EXPECTED TO APPROACH/POSSIBLY MOVE INTO PORTIONS OF THE AREA OVERNIGHT. WITH THE SPC MESOPAGE STILL SHOWING 1000-2000 J/KG OF MUCAPE ACROSS OUR NORTHWEST/NORTHERN PIEDMONT AND THE LATEST RAP AND HRRR SHOWING THE POTENTIAL FOR SOME OF THIS ACTIVITY TO MOVE INTO THIS AREA (NW/N PIEDMONT) WILL LEAVE A CHANCE OF SHOWERS AND STORMS IN THE FORECAST FOR THIS AREA. HOWEVER.. WITH THE LACK OF GOOD DEEP SHEAR AND DAYTIME HEATING THINK THIS LINE WILL CONTINUE TO SHOW A WEAKENING TREND AS IT MOVES INTO NW/N PORTIONS OF CENTRAL NC AROUND MIDNIGHT OR SHORTLY AFTER. THUS... WOULD EXPECT ANY OF THIS WEAKENING LINE TO REMAIN BELOW SEVERE LIMITS. WHERE HEAVY RAINFALL OCCURRED THIS PAST AFTERNOON-EVENING (GENERALLY ALONG AND SOUTH OF A LINE FROM ASHEBORO TO RALEIGH TO WILSON) AND SKIES PARTIALLY CLEAR OVERNIGHT... WE COULD SEE PATCHES OF FOG DEVELOP DURING THE PRE-DAWN HOURS OF WEDNESDAY. MIN TEMPS NEAR 70- LOWER 70S. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... AS OF 335 PM TUESDAY... SHEAR AXIS AND ATTENDANT SURFACE BOUNDARY WILL LIE ACROSS THE SOUTHERN COUNTIES OF CENTRAL NC. ISOLATED SHOWERS AND STORMS ALONG THIS FEATURE WEDNESDAY MORNING WILL GROW IN COVERAGE AS THE ATMOSPHERE HEATS UP...LEADING TO GREATER LOW LEVEL INSTABILITY. RELATIVELY WEAK STEERING FLOW SUGGEST THAT THE STORMS WILL BE SLOW MOVING. IF STORMS OCCUR OVER URBAN LOCATIONS...THIS MAY LEAD TO MINOR FLOODING OF STREETS AND POOR DRAINAGE AREAS. PLAN TO CAP POPS AT 50 PERCENT ACROSS THE SOUTH...DWINDLING TO 25-35 PERCENT ACROSS THE NW. MAX TEMPS WEDNESDAY DEPENDENT ON WHEN CONVECTIVE COVERAGE INCREASES AND WHETHER ANY PERIODS OF PARTIAL SUN OCCUR. BETTING ON SOME PARTIAL SUN INT HE LATE MORNING-EARLY AFTERNOON PRIOR TO CONVECTION INCREASING AFTER 2-3 PM. IF SKIES REMAIN OVERCAST OR CONVECTION BECOMES ACTIVE BY LUNCHTIME...MAX TEMPS MAY END UP BEING 5-6 DEGREES COOLER. CONTINUED WARM AND MUGGY WEDNESDAY NIGHT WITH SCATTERED CONVECTION SLOWLY DIMINISHING/DISSIPATING. MIN TEMPS NEAR 70-LOWER 70S. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 255 PM TUESDAY... FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT... PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL. FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC... ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING. WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING OVER THE CAROLINAS. -GIH && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 150 AM WEDNESDAY... A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z. MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS. HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS TIME. ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING. OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE THIS WEEKEND INTO EARLY NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BSD/WSS NEAR TERM...BSD/WSS SHORT TERM...WSS LONG TERM...HARTFIELD AVIATION...BLS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1231 AM EDT WED SEP 3 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD NORTHEAST UP THE APPALACHIAN MOUNTAINS THROUGH WEDNESDAY NIGHT AND OFF THE EAST COAST BY THURSDAY NIGHT. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA THURSDAY FOLLOWED BY A COLD FRONT FRIDAY EVENING. HIGH PRESSURE WILL BUILD SOUTHEAST ACROSS THE REGION INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... CONVECTION WITH DIFFUSE COLD FRONT NOW REDUCED TO 3 SMALL CLUSTERS. VERY LITTLE LIGHTNING OCCURRING. RUC HANGS ON TO A FEW CELLS THRU THE NIGHT SO WILL SLOW POP DROP OFF ENOUGH TO KEEP SLIGHT CHANCE GOING LONGER INTO THE NIGHT. MUCH OF THE CLOUD COVER FROM EARLIER IN THE DAY HAS DISSIPATED LEAVING PATCHY LOWER CLOUDS WITH BAND OF JET INDUCED CIRRUS ABOVE. WEAK COLD ADVECTION LOOKS EVEN MORE LIKELY TO NOT BE STRONG ENOUGH TO BRING IN THE DRIER AIR AS QUICK AS THOUGHT EARLIER SO WILL INCH LOWS UP EVEN ANOTHER DEG OVER THE SE 2/3 OF THE AREA. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... BROAD UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA OVERNIGHT SETTING UP A ZONAL FLOW ACROSS THE COUNTRY ONCE AGAIN. SURFACE HIGH WILL BUILD NORTHEAST AND THEN EAST OF THE AREA BY WEDNESDAY NIGHT. WARM AIR ADVECTION WILL RESUME ON THURSDAY WITH A PRETTY GOOD SURGE OF WARM AIR RACING NORTHEAST INTO THE FORECAST AREA. 850 MB TEMPERATURES RISE FROM 16C WEDNESDAY NIGHT TO 20C BY FRIDAY. INCREASED DEW POINT AIR WILL RETURN AND BRING WITH IT HIGHER HUMIDITY ON FRIDAY. COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE REGION FRIDAY EVENING. CONVECTION IS EXPECTED TO REMAIN ASSOCIATED WITH THE COLD FRONT FRIDAY AFTERNOON INTO FRIDAY NIGHT. OTHERWISE...NO MAJOR THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED PERIOD UNTIL FRIDAY AFTERNOON. WILL HAVE TO KEEP AN EYE ON THE COLD FRONT FRIDAY FOR SEVERE POTENTIAL DUE TO IDEAL TIMING IN THE HEAT OF THE DAY. && .LONG TERM /SATURDAY THROUGH TUESDAY/... A SURFACE COLD FRONT WILL BE JUST ABOUT OUT OF THE AREA AT DAYBREAK SATURDAY. THERE COULD BE A FEW SHOWERS ALONG AND BEHIND THE FRONT BUT RAPID DRYING WILL OCCUR DURING THE AFTERNOON. READINGS NEXT WEEKEND WILL BE BACK BELOW NORMAL WITH LOWS MONDAY MORNING POSSIBLY GETTING INTO THE 40S. SUNDAY WILL BE A PLEASANT DAY WITH ABUNDANT SUNSHINE. THE FALL LIKE WEATHER WILL CONTINUE ON MONDAY. THE SURFACE HIGH RESPONSIBLE FOR THE QUIET WEATHER WILL EVENTUALLY MOVE OFF TO THE EAST ON TUESDAY ALLOWING WARMER SOUTHERLY FLOW TO RETURN. EXPECT TEMPS TUESDAY TO AVERAGE NEAR NORMAL. PRECIP CHANCES SHOULD HOLD OFF TILL JUST AFTER THE PERIOD ENDS. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... HIGH PRESSURE WILL BUILD IN TODAY BEHIND A COLD FRONT THAT WILL BE SOUTH OF THE AREA. MAIN CONCERN IS FOR EARLY OVERNIGHT/EARLY MORNING FOG AND LOW STRATUS DEVELOPING ACROSS THE AREA. AMPLE LOW LEVEL MOISTURE...DRYING ALOFT...AND LIGHT WINDS SHOULD ALLOW THE FOR TO DEVELOP WITH WIDESPREAD MVFR/IFR RESTRICTIONS DEVELOPING BEFORE DAYBREAK. AFTER FOG LIFTS EXPECT VFR CONDITIONS THROUGH THE DAY. NEAR LAKE ERIE...KCLE AND KERI...EXPECT LAKE BREEZE TO DEVELOP IN WEAK GRADIENT. OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY EVENING INTO SATURDAY WITH THE NEXT COLD FRONT. && .MARINE... A SURFACE COLD FRONT WILL MOVE EAST OF THE LAKE BY EARLY THIS EVENING. LINGERING SHOWERS OVER THE LAKE WILL ALSO BE GONE BY THAT TIME. EXPECT THE FLOW TO BECOME WESTERLY BEHIND THE FRONT AND THEN LIGHT AND VARIABLE OVERNIGHT. LIGHT FLOW WILL THEN CONTINUE WEDNESDAY WITH SOUTHERLY FLOW DEVELOPING ON THURSDAY AS A SURFACE RIDGE PUSHES EAST OF THE LAKE. SOUTH TO SOUTHWEST FLOW WILL THEN GRADUALLY INCREASE AHEAD OF A COLD FRONT THAT WILL DROP SOUTH ACROSS THE LAKE EARLY SATURDAY. MORE PRECIP IS LIKELY WITH THIS FRONT WITH THE FLOW BECOMING NORTH BEHIND IT. DO NOT THINK SPEEDS WILL BE STRONG ENOUGH FOR SMALL CRAFT HEADLINES. NORTHERLY FLOW WILL CONTINUE THROUGH SUNDAY. SPEEDS MOST IF NOT THE ENTIRE PERIOD WILL BE UNDER 15 KNOTS. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY SHORT TERM...LOMBARDY LONG TERM...KUBINA AVIATION...TK MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1132 PM CDT TUE SEP 2 2014 .AVIATION... CONFIDENCE IS A BIT LOWER THAT AN IFR OR MVFR CLOUD DECK WILL DEVELOP NEAR OR SOUTHWEST OF KLBB EARLY WEDNESDAY...AND ADVECT OVER THE AIRPORT. LATEST WRF/NAM HAS DRIED THE H850 MB A BIT WHILE THE RAP H850 MB LAYER IS SLIGHTLY MORE MOIST THAN PREVIOUS RUNS. ALTHOUGH WE WILL BACK OFF SLIGHTLY ON THE CLOUD LAYER POTENTIAL... WE WILL RETAIN SOME CHANCE OF A DECK IMPACTING KLBB JUST AFTER DAYBREAK WEDNESDAY. OTHERWISE...UPPER LEVEL HIGH PRESSURE WILL DOMINATE THROUGH WEDNESDAY WITH WEAKER FLOW THAN TUESDAY AND LESSER THUNDER CHANCES. A LOW LEVEL JET TONIGHT SHOULD REMAIN JUST TO THE NORTH OF THE AREA. RMCQUEEN && .PREV DISCUSSION... /ISSUED 706 PM CDT TUE SEP 2 2014/ AVIATION... ISOLATED THUNDERSTORMS APPEAR TO HAVE BY-PASSED KLBB WHILE REMAINING FAR WEST OF KCDS THIS EVENING. VFR EXPECTED TO DOMINATE OTHER THAN A RISK FOR AN IFR/MVFR CLOUD LAYER TO DEVELOP JUST AFTER DAYBREAK WEDNESDAY AT KLBB. RMCQUEEN PREV DISCUSSION... /ISSUED 531 PM CDT TUE SEP 2 2014/ UPDATE... THUNDERSTORMS HAVE DEVELOPED OVER THE WESTERN AND CENTRAL SOUTH PLAINS...A BIT SOUTH OF PREVIOUS BEST-GUESS...BUT GIVE SHORT TERM SOLUTIONS SOME CREDIT. WE HAVE UPDATED FOR LOW COVERAGE THUNDER THROUGH EARLY THIS EVENING. 1500-2000 JOULES PER KILOGRAM OF CONVECTIVE ENERGY BUT VERY LITTLE SHEAR CONTRIBUTING TO BRIEF HEAVY SHOWERS AND BRIEF MOSTLY WEAK HAIL INDICATIONS AT THIS TIME. ACTIVITY SHOULD TAKE ON BETTER NORTHERLY DRIFT...THOUGH BELIEVE MOST ACTIVITY WILL RELENT BY DARK. RMCQUEEN PREV DISCUSSION... /ISSUED 306 PM CDT TUE SEP 2 2014/ SHORT TERM... FOCUS IN THE SHORT TERM IS ON SMALL CHANCE FOR ISOLATED SHOWERS AND/OR THUNDERSTORMS LATE THIS AFTN AND THIS EVENING. RADAR IS QUIET ATTM BUT SATELLITE SHOWING AN AREA OF CUMULUS DEVELOPMENT TO THE EAST AND SOUTHEAST OF LUBBOCK IN AN AREA WHERE OBJECTIVE ANALYSIS SHOWS ENHANCED INSTABILITY AND WEAKENING INHIBITION. SOME VERY MODEST LOW LEVEL SPEED CONVERGENCE AND MOISTURE ADVECTION IN THIS AREA MAY NOT HELP TOO MUCH BUT CERTAINLY WILL NOT HURT. A WEAK FRONTAL BOUNDARY PULLED UP STATIONARY NEAR A MORTON TO TULIA LINE WITH WEAK CONFLUENCE IN ITS VICINITY BUT WITH SFC DEW POINTS ABOUT 5 DEGREES LOWER THAN IN THE FORMER AREA. WOULD EXPECT THESE TWO AREAS HAVE THE BEST CHANCE OF SEEING CONVECTIVE DEVELOPMENT. 12Z WRF-NAM HIGHLIGHTS THE LATTER WHILE RECENT RUNS OF THE HRRR FEATURES THE FORMER. EITHER WAY WILL LIKELY BE DIFFICULT TO GENERATE ANYTHING OTHER THAN SMALL-SCALE AND ISOLATED SHOWERS WITH AREAL COVERAGE NOT WARRANTING MENTION IN THE ZONE FCST ATTM. WEDNESDAY SHOULD BE EVEN MORE DIFFICULT TO PRODUCE PRECIP WITH STRENGTHENING HIGH PRESSURE OVERHEAD AND LOW LEVEL FLOW BECOMING MORE UNIFORM FROM THE SOUTH. TEMPS TO REMAIN WARMER THAN NORMAL WITH BOTH LOWS AND HIGHS NEAR WARMER MAV GUIDANCE LOOKING MORE LIKELY ATTM. LONG TERM... ONLY MINOR CHANGES TO THE LONG TERM FORECAST FOR THIS ITERATION...AS A MUTED COOLING TREND WILL BE FOLLOWED BY A POTENTIALLY WET WEEKEND FOR PARTS OF THE REGION. BY WEDNESDAY EVENING...A MOSTLY ZONAL UPPER FLOW REGIME WILL BE IN PLACE ACROSS THE CONUS...WITH AN ELONGATED UPPER RIDGE IN PLACE ACROSS MOST OF THE SOUTH...INCLUDING WEST TEXAS. WHILE THIS WILL CONTINUE TO ENSURE MOSTLY DRY CONDITIONS THROUGH THE END OF THE WORK WEEK...GRADUALLY DROPPING 1000-500 MB THICKNESSES WILL ALLOW TEMPERATURES TO INCREMENTALLY FALL BACK TO A MORE REASONABLE UPPER 80S ON THE SOUTH PLAINS TO MID 90S ON THE ROLLING PLAINS. BY LATE IN THE WEEK AND THROUGH THE WEEKEND...A BROAD UPPER TROUGH WILL PUSH EASTWARD ACROSS THE NORTHERN CONUS...SENDING A MODEST COLD FRONT SOUTHWARD THROUGH THE CENTRAL PLAINS AND AT LEAST THE TEXAS PANHANDLE. MEANWHILE DEEPER MONSOONAL MOISTURE...POSSIBLY WITH A CONNECTION TO REMNANTS OF TROPICAL STORM DOLLY...WILL BE DRAWN NORTHWARD INTO THE SOUTHWEST AND EVENTUALLY EASTWARD AS IT GETS CAUGHT IN THE WESTERLY UPPER FLOW ASSOCIATED WITH THE PREVIOUSLY MENTIONED TROUGH. ALL OF THIS IS EXPECTED TO RESULT IN INCREASING RAIN CHANCES BEGINNING AS EARLY AS LATE FRIDAY...AND POSSIBLY LASTING THROUGH LATE SUNDAY DEPENDING ON A FEW FACTORS. THE MOST PROMINENT OF THESE FACTORS SEEMS TO BE THE TIMING AND STRENGTH OF THE APPROACHING COLD FRONT...AS THE GFS AND ECMWF REMAIN ABOUT 24 HOURS APART IN THIS REGARD. THE GFS INDICATES A SLOWER...WEAKER FRONT REACHING THE NORTHERN BORDER OF THE CWA LATE SATURDAY AFTERNOON AND WASHING OUT ACROSS THE CWA SUNDAY. MEANWHILE...THE ECMWF SOLUTION BRINGS THIS FRONT INTO THE AREA AS EARLY AS LATE FRIDAY...AND PUSHES THE BOUNDARY WELL THROUGH THE CWA BY LATE SATURDAY. THE LATTER SOLUTION NOT SURPRISINGLY DEVELOPS THE HEAVIEST PRECIPITATION DURING THE LATE FRIDAY THROUGH SATURDAY TIME FRAME...WHILE THE GFS SEEMS TO BE FOCUSING ON THE LATE SATURDAY THROUGH LATE SUNDAY TIME FRAME. GIVEN THAT THE BOUNDARY WILL BE WELL REMOVED FROM ITS PARENT TROUGH BY THE TIME IT REACHES THIS LATITUDE...WE WILL CONTINUE TO SIDE WITH THE SLOWER GFS SOLUTION AND HIGHLIGHT LATE SATURDAY WITH THE HIGHEST POPS. LIKEWISE...LOW END POPS WERE ALSO EXTENDED THROUGH SUNDAY EVENING GIVEN THAT IN THIS SLOWER SCENARIO REMNANTS OF THIS BOUNDARY AND AMPLE MOISTURE WOULD LIKELY LINGER THROUGH THIS PERIOD. HOWEVER...UNCERTAINTIES REGARDING FRONTAL TIMING AND STRENGTH ARE COMPOUNDED FURTHER ON SUNDAY WITH THE POSSIBILITY OF LINGERING NOCTURNAL CONVECTION AND STABILIZING OUTFLOWS. BY MONDAY...THE UPPER RIDGE IS EXPECTED TO SLIGHTLY AMPLIFY ACROSS THE SOUTHERN PLAINS WHILE THE COLUMN DRIES CONSIDERABLY. THIS SHOULD TAPER OFF PRECIPITATION CHANCES UNTIL LATER IN THE WEEK WHEN ANOTHER POSSIBLY STRONGER COLD FRONT MOVES THROUGH THE REGION. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 61 92 62 90 62 / 10 0 10 10 10 TULIA 68 93 66 91 66 / 20 0 10 0 10 PLAINVIEW 68 93 66 90 66 / 20 0 0 0 10 LEVELLAND 66 92 66 90 67 / 20 0 10 10 0 LUBBOCK 72 93 68 92 67 / 20 0 0 10 0 DENVER CITY 66 91 66 89 66 / 20 0 10 10 10 BROWNFIELD 68 93 67 90 67 / 20 0 0 10 0 CHILDRESS 75 97 75 96 72 / 10 0 0 0 0 SPUR 73 97 72 94 71 / 10 0 0 10 10 ASPERMONT 76 99 74 96 73 / 0 0 0 10 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/05
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1059 PM MDT TUE SEP 2 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 420 PM MDT TUE SEP 2 2014 MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE CRITICAL FIRE WEATHER CONDITIONS ACROSS THE CWA. IT TOOK A LITTLE WHILE FOR RH VALUES TO DROP TO CRITICAL LEVELS THIS AFTERNOON...BUT WE ARE CURRENTLY SEEING A RH OF AROUND 15 PERCENT IN THE FOOTHILLS OF THE LARAMIE RANGE (FIRE WEATHER ZONES 309 AND 301). RH VALUES ARE GENERALLY 15-20 PERCENT TO THE WEST OF THE LARAMIE RANGE. WITH GUSTS TO 25-30 MPH THROUGH EARLY EVENING...THIS CONTINUES TO LOOK LIKE A MARGINAL RED FLAG EVENT AND WILL KEEP THE WARNINGS GOING. CLOUD COVER THIS AFTERNOON IS QUITE LIMITED WITH ONLY ISOLATED CUMULUS. SFC MOISTURE IS BETTER IN SOUTHERLY WINDS JUST TO THE EAST OF THE CWA (DEUEL AND GARDEN COUNTIES) BUT IT WILL BE TOUGH TO ADVECT THIS MOISTURE WESTWARD. THE HRRR MODEL ALONG WITH THE OTHER MODELS DO NOT SHOW ANY QPF OVER THE PANHANDLE TONIGHT SO WILL KEEP SLIGHT CHANE POPS OUT OF THE FCST. WEDNESDAY CONTINUES TO LOOK LIKE A MORE CRITICAL FIRE WEATHER DAY OVER THE REGION. A SHORTWAVE MOVING FROM WASHINGTON INTO MONTANA WILL INDUCE PRESSURE FALLS OVER WESTERN SOUTH DAKOTA WHICH STRENGTHENS THE PRESSURE GRADIENT OVER ESPECIALLY SOUTHEAST WY. MOS GUIDANCE SHOWS WINDS ABOUT 5 KTS HIGHER THAN THIS AFTN ALONG WITH AN ADDITIONAL 5 DEGREES OF WARMING. THE FIRE WEATHER WATCH FOR TOMORROW AFTN INCLUDES TWO ZONES (310 AND 306) THAT ARE NOT INCLUDED IN TODAYS RED FLAG WARNING. THIS LOOKS GOOD SINCE BOTH THESE ZONES WERE CLOSE TO HITTING THE CRITERIA TODAY AND CONDITIONS WILL BE DRIER AND MORE BREEZY TOMORROW. THE DEEP SOUTHWESTERLY FLOW WILL RESULT IN A VERY WARM DAY WITH HIGHS RISING INTO THE UPPER 80S TO MID 90S ACROSS THE PLAINS. THIS COULD BE ONE OF THE WARMEST DAYS FOR THE REST OF THE YEAR SINCE A COLD FRONTAL PASSAGE IS STILL PROGGED FOR THURS MORNING. TEMPS WILL DROP CLOSE TO 20 DEGREES ON THURS. STILL NO GOOD CHANCE OF PRECIP THROUGH AT LEAST THURS EVENING. COULD BE ISOLATED SHOWERS DEVELOPING BY THURS NIGHT ALTHOUGH THE MODEL TREND HAS BEEN TO SHIFT THE MORE WIDESPREAD RAIN WELL TO THE SOUTH OVER NORTHWEST KS. .LONG TERM...(FRIDAY THROUGH MONDAY NIGHT) ISSUED AT 420 PM MDT TUE SEP 2 2014 MODELS ARE IN FAIR AGREEMENT WITH THE MEDIUM RANGE PERIOD SHOWING A PERSISTENT QUASI-ZONAL PATTERN OVER THE CENTRAL CONUS. TEMPERATURES WILL START OFF BELOW AVERAGE ON FRIDAY IN THE POST FRONTAL AIRMASS...WITH THE SFC HIGH SLIDING TO THE SOUTHEAST ACROSS THE CENTRAL PLAINS. SFC WINDS ACROSS THE HIGH PLAINS WILL BE OUT OF THE SOUTHEAST AS THE SFC HIGH SLIDES SOUTHEAST...WITH CONVECTION DEVELOPING OVER THE MOUNTAINS IN THE LATE AFTERNOON IN THIS LLVL UPSLOPE REGIME. SHOULD STAY FAIRLY CAPPED ACROSS THE PLAINS WITHIN THE COOLER AIRMASS...BUT CANT RULE OUT SHOWERS/WEAK TSTORMS MAINTAINING AS THEY MOVE OFF THE MOUNTAINS AS A 70 KT JET AND SHORTWAVE ENERGY WILL BE MOVING OVERHEAD AT THIS TIME. SATURDAY LOOKS VERY SIMILAR ALBEIT WITH WEAKER UPSLOPE FLOW AND SLIGHTLY WARMER TEMPS/HIGH INSTABILITY. SUNDAY AND MONDAY COULD SEE A BIT MORE SUBTROPICAL MOISTURE ADVECT UP FROM THE SOUTHWEST AS A TROUGH DIGS ALONG THE WEST COAST AND MOVES ACROSS THE GREAT BASIN. THE DEEPEST MOISTURE LOOKS TO REMAIN TO OUR SOUTH...BUT CAN SEE SOME OF THIS MOISTURE MAKING IT UP TO SOUTHERN PORTIONS OF THE CWA SO WILL MAINTAIN AT LEAST SLIGHT CHANCE POPS FOR MUCH OF THE CWA. TEMPS WILL INCREASE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR BY MONDAY AS THE UPPER TROUGH DEEPENS AND A WARM AIR ADVECTION PATTERN DEVELOPS OVER THE ROCKIES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING) ISSUED AT 1058 PM MDT TUE SEP 2 2014 VFR CONDITIONS TO PREVAIL THRU THE PERIOD. WINDS WILL BE GENERALLY LIGHT AT LESS THAN 10 KNOTS OVERNIGHT...BUT BECOME GUSTY AFTER 16Z WEDNESDAY. && .FIRE WEATHER... ISSUED AT 649 PM MDT TUE SEP 2 2014 PER OUR FIRE WEATHER BRIEFING AND MODEL GUIDANCE...RED FLAG CONDITIONS LOOKING EVEN MORE LIKELY FOR PORTIONS OF SOUTHEAST WYOMING ON WEDNESDAY...THUS WE HAVE UPGRADED THE FIRE WEATHER WATCH TO A RED FLAG WARNING...AND HAVE ALSO CANCELLED THE RED FLAG WARNING THAT WAS IN EFFECT FOR THIS AFTERNOON. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...RED FLAG WARNING FROM NOON TO 7 PM MDT WEDNESDAY FOR WYZ301-302- 304-306-309-310. NE...NONE. && $$ SHORT TERM...FINCH LONG TERM...RJM AVIATION...HAHN FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
955 AM EDT WED SEP 3 2014 .DISCUSSION... LATEST RUC ANALYSIS SHOWING AN H100-H70 HI PRES RIDGE EXTENDING FM THE NRN GULF COAST INTO THE W ATLC...BISECTED BY AN ERLY WAVE BTWN FL AND THE BAHAMA BANK. WV SAT IMAGERY CONTINUES TO SHOW A BAND OF DRY MID LYR AIR DRAPED OVER THE S HALF OF FL...THOUGH DEEPER MOISTURE ASSOCD WITH THE WAVE WAS IMPINGING ON THE SE FL COAST. MORNING RAOBS CONFIRM THIS WITH PWAT READINGS ARND 1.6" AT KXMR/KTBW...INCREASING TO 1.9" AT KMFL. MID LVL THERMODYNAMIC PROFILE HAS BECOME A SLIGHTLY MORE UNSTABLE OVER THE PAST 24HRS WITH H70 TEMPS ARND 8C...H50 TEMPS ARND -7C...THOUGH LAPSE RATES THRU THE LYR ARE LANGUISHING BTWN 5.5-6.0C/KM. ONE NOTEWORTHY TREND ON THE KXMR SOUNDING IS AN INCREASE IN H100-H70 MOISTURE. TREND WILL CONTINUE THRU THE DAY AS RUC ANALYSIS SHOWS MEAN RH VALUES THRU THE LYR INCREASING UPSTREAM TO ARND 85PCT. ALTHOUGH THE ASCENDING BACKSIDE OF THE APPROACHING ERLY WAVE REMAINS BACK OVER THE BAHAMA BANK/FL STRAITS...WITH SFC DEWPOINTS HOLDING IN THE L/M70S...SHOULD SEE HIGHER PRECIP COVERAGE ACRS E CENT FL THAN IN RECENT DAYS. LCL PRECIP MODELS FOCUSING MOST ACTIVITY OVER THE INTERIOR AND ALONG THE TREASURE COAST...BY AND LARGE BYPASSING THE SPACE COAST. FCST IS REASONABLE AS STEERING LVL WINDS WILL SHIFT TO THE SE AS THE WAVE PUSHES ACRS THE REGION THRU LATE AFTN. MINOR ADJUSTMENTS TO PRECIP TIMING AND COVERAGE...BUT OVERALL TREND WILL REMAIN. COASTAL SHRAS THRU ERLY AFTN WITH PRECIP SHIFTING INLAND ON THE SEABREEZE. SCT TSTMS DVLPG INTERIOR THRU LATE AFTN...LINGERING DRY AIR ALOFT WILL ADD TO DOWNBURST POTENTIAL. && .AVIATION... THRU 03/16Z...E/SE SFC WNDS AOB 8KTS...BRIEF ISOLD MVFR COASTAL SHRAS BTWN KTIX-KSUA. BTWN 03/16Z-03/24Z...E/SE SFC WND 8-12KTS...SW OF KVRB-KDED SCT MVFR SHRAS/ISOLD IFR TSRAS WITH PSBL SFC WND G25-30KTS...E OF KVRB-KDED ISOLD MVFR SHRAS. AFT 04/00Z...SE SFC WNDS AOB 5KTS...SCT MVFR SHRAS/ISOLD IFR TSRAS CSTL SITES. && .MARINE... ERLY WAVE AXIS BTWN THE FL PENINSULA AND THE BAHAMA BANK WILL DRIFT WEST AND PRODUCE A GENTLE TO MODERATE E/SE BREEZE ACRS THE LCL ATLC...SEAS SEAS 2-3FT WITH DOMINANT PDS AOA 8SEC. SHRA/TSTM ACTIVITY WILL INCREASE THRU LATE AFTN AS THE E FL PENINSULA GAINS THE WAVE`S ASCENDING REAR FLANK. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ FORECAST/AVIATION...BRAGAW RADAR/IMPACT WX.....CRISTALDI
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
651 AM CDT WED SEP 3 2014 .UPDATE... ISSUED AT 645 AM CDT WED SEP 3 2014 A NARROW N-S BAND OF WIDELY SCATTERED THUNDERSTORMS DEVELOPED OVER THE LAST HALF HOUR THROUGH THE HIGHWAY 83 CORRIDOR.THIS APPEARS TO BE ASSOCIATED WITH AN 850 MB MOISTURE TRANSPORT SIGNAL ACROSS SOUTHWEST KANSAS. THE HRRR MODEL IS ALSO PICKING UP ON THIS ACTIVITY AND HAVE UPDATED FOR A MENTION OF THUNDERSTORMS THROUGH MID MORNING FROM GARDEN CITY TO DODGE CITY AND HAYS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 339 AM CDT WED SEP 3 2014 THE WEAK FRONTAL BOUNDARY THAT WAS RESIDING ALONG THE WESTERN KANSAS- OKLAHOMA BORDER CONTINUED TO SLOWLY DISSOLVE AS WINDS NORTH OF THE FRONT WERE STILL VEERING FROM 090 TO 140 AT DDC. WINDS WERE ALSO 10 TO 12 KNOTS WHICH WAS KEEPING THE BOUNDARY LAYER MIXED ENOUGH TO PREVENT FOG DEVELOPMENT. LOW STRATUS IS ABOUT ALL WE CAN EXPECT EXCEPT FOR EXTREME WEST-CENTRAL KANSAS, SO WE WILL KEEP AREAS OF 1/2SM FOG CONFINED TO SYRACUSE TO SCOTT CITY AREAS. VERY WARM LOWER TROPOSPHERIC AIR WILL CONTINUE TO EXPAND NORTH-NORTHEASTWARD THROUGH THE DAY. HIGHS AROUND 100F ARE LIKELY ALONG/WEST OF HIGHWAY 83 TO THE COLORADO BORDER. LEE TROUGH CONVERGENCE AXIS WILL SET UP ALONG THE COLORADO BORDER AS WELL BY MID-LATE AFTERNOON, AND ALL THE MESOSCALE AND STORM SCALE MODELS (NAM12, WRF-ARW, WRF-NMMB, RAP13, AND EVEN THE 13-15HR VALID TIMES OF THE LATEST HRRR) SHOW SOME SEMBLANCE OF CONVECTION INITIATING SOMEWHERE ACROSS THE WESTERN SIX COUNTIES (HAMILTON-MORTON-STANTON-KEARNY-GRANT-STEVENS), SO WE WILL INTRODUCE SOME 20-30 POPS IN THIS AREA. GIVEN THE SIGNIFICANT TEMPERATURE-DEWPOINT SPREADS WITH TEMPS IN THE UPPER 90S/100 AND DEWPOINTS IN THE LOW TO MID 50S, DRY MICROBURSTS ARE CERTAINLY GOING TO BE THE GREATEST THREAT FROM CONVECTION...ESPECIALLY ON THE NORTH SIDE OF CONVECTION WITH OUTFLOW WIND ADDING TO THE BACKGROUND STRONG SYNOPTIC WINDS (WHICH OUTSIDE OF STORMS WILL BE 20 TO 25 KNOTS SUSTAINED). GIVEN THE LACK OF ANY LARGE SCALE FORCING FOR ASCENT, ANY CONVECTION WHICH DEVELOPS SHOULD DISSIPATE NOT TOO LONG AFTER SUNSET. ANOTHER MILD NIGHT IS FORECAST TONIGHT INTO EARLY THURSDAY MORNING WITH CONTINUED SOUTH WINDS OF 14 TO 17 KNOTS. THIS WILL KEEP THE BOUNDARY LAYER MIXED THROUGH THE NIGHT WITH LOWS ONLY DOWN TO 70- 73F FOR MUCH OF SOUTHWEST AND SOUTH CENTRAL KANSAS. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 353 AM CDT WED SEP 3 2014 OVERALL EXPECTATIONS FOR THE EXTENDED PERIOD FORECAST HAVE NOT CHANGED IN THE LAST DAY, HOWEVER THE SENSIBLE WEATHER IMPACTS MAY BECOME MORE CLEAR WITH TIME. THURSDAY WILL STILL BE A WARM DAY WITH SOUTHERLY, SLIGHTLY DOWNSLOPE COMPONENT BREEZY CONDITIONS IN ADVANCE OF AN APPROACHING COLD FRONT WHICH MAY INFLUENCE THE EXTREME WEST CENTRAL COUNTIES DURING THE DAY. AGAIN THE NAM WAS FOLLOWED FAIRLY CLOSE FOR THIS DAY WITH RESPECT TO HIGHS AND CLOUD COVER. THUNDERSTORMS WILL BECOME A THREAT INTO THE EVENING AS THE FRONT MOVES THROUGH THE AREA, BUT AGAIN UPPER SUPPORT IS SOMEWHAT LACKING. POP TRENDS ARE INCREASING INTO THE SATURDAY PERIOD AS WELL AS THE UPPER WAVE EJECTS ACROSS THE NORTHERN PLAINS, WHICH WILL INCREASE MID LEVEL BAROCLINICITY ACROSS THE CENTRAL HIGH PLAINS. NAM MODEL SATURATES THE BOUNDARY LAYER NICELY WITH SOME ELEVATED CAPE AND UPSLOPE SURFACE FLOW SUGGESTING SHOWERS THUNDERSTORMS AND PROBABLY FOG DEVELOPMENT AS WELL OVERNIGHT FRIDAY INTO SATURDAY MORNING. FRIDAY AND SATURDAY WILL BE RELATIVELY COOL DAYS, WHILE CLOUDS AND SHOWERS/ISOLATED THUNDERSTORMS MAY LINGER INTO SATURDAY EVENING IN THE SOUTHERN COUNTIES. SHORTWAVE ENERGY IS SHOWN BY THE GFS TO SPREAD ACROSS THE HIGH PLAINS AGAIN BY MONDAY, BRINGING ADDITIONAL CHANCES FOR CONVECTION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1259 AM CDT WED SEP 3 2014 THE AVIATION FORECAST THROUGH 12-15Z TIME FRAME WEDNESDAY WILL BE CHALLENGING. WE WILL MAINTAIN THE PESSIMISTIC FORECAST OF CEILING FALLING TO AROUND 200-300 FEET AT GCK AND DDC STARTING AROUND 10Z. THE LIFR CONDITIONS SHOULD EXIST FOR AT LEAST A COUPLE HOURS BEFORE DRIER AIR MOVES IN FROM THE SOUTHWEST AS LOW LEVEL SOUTHWEST MOMENTUM INCREASES BY DAYBREAK. FOR NOW, WE WILL KEEP HYS AWAY FROM THE IFR/LIFR CONDITIONS, BUT THIS IS ALSO A LOW CONFIDENCE FORECAST WITH AMENDMENTS QUITE POSSIBLE. SOUTHWEST WINDS WILL INCREASE DURING THE LATE MORNING THROUGH MIDDAY TIME FRAME, GUSTING TO 30+ KNOTS BY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... DDC 97 72 96 64 / 10 10 10 40 GCK 98 70 97 61 / 10 30 20 40 EHA 99 68 96 63 / 20 20 10 60 LBL 100 71 97 66 / 10 20 0 40 HYS 98 72 97 61 / 10 10 20 50 P28 97 74 98 70 / 10 10 0 30 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...RUSSELL SHORT TERM...UMSCHEID LONG TERM...RUSSELL AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS CARIBOU ME
939 AM EDT WED SEP 3 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION THIS MORNING. HIGH PRESSURE WILL BUILD ACROSS THE REGION LATER TODAY INTO THURSDAY. THE NEXT COLD FRONT WILL MOVE THROUGH FRIDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... 935 AM UPDATE...THE COLD FRONT HAS PUSHED OFFSHORE, AND THE HEAVY PRECIPITATION THAT AFFECTED THE REGION EARLY THIS MORNING HAS EXITED INTO CANADA. WHILE DRIER AIR IS WORKING INTO THE REGION, THERE IS ALSO A WEAK SHORTWAVE IN THE FLOW ALOFT WHICH WILL TREK ACROSS NORTHERN MAINE THIS AFTERNOON. THIS COMBINED WITH SOME HEATING COULD BE ENOUGH TO ALLOW CUMULUS AND EVEN A FEW SHOWERS TO DEVELOP THIS AFTERNOON, MAINLY ACROSS NORTHERN AROOSTOOK COUNTY. THE HRRR MODEL BACKS UP THIS THINKING. ELSEWHERE, EXPECT JUST PARTLY TO MOSTLY SUNNY SKIES. HAVE UPDATED THE FORECAST TO INTRODUCE A SLIGHT CHANCE OF A SHOWER AND ADJUST CLOUD COVER. OTHERWISE, NO OTHER CHANGES WERE NEEDED. PREVIOUS DISCUSSION...A COLD FRONT IS CURRENTLY MOVING ACROSS THE REGION. A LINE OF SHOWERS AND SOME THUNDERSTORMS IS ACCOMPANYING THIS SYSTEM AS IT MOVES ACROSS THE STATE. BOTH THE NAM AND GFS ARE DOING A GOOD JOB WITH BOTH PRECIPITATION AND TIMING... SO WILL USE A MODEL CONSENSUS APPROACH AND BLEND THESE MODELS FOR POP...QPF AND SKY COVER. BEHIND THE FRONT DRIER CONDITIONS AND A COLDER AIR MASS WILL MOVE IN FROM HE WEST ALONG WITH STRONG HIGH PRESSURE. BASED ON VERIFICATION OVER LAST 24 HOURS HAVE USED THE BIAS CORRECTED RAW BLEND FOR MAXIMUM AND MINIMUM TEMPERATURE AND DEWPOINT. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... HIGH PRES WILL GRAB CONTROL OF THE REGION`S WX RIGHT THROUGH THIS TERM WITH A COLD FRONT APPROACHING THE REGION FROM THE WEST LATER IN THE DAY ON FRIDAY. UNTIL THEN, IT LOOKS LIKE WARM TEMPERATURES FOR EARLY SEPTEMBER W/DAYTIME HIGHS ON THURSDAY IN THE UPPER 70S TO AROUND 80 WITH EVEN WARMER READINGS ON FRIDAY. WE ARE TALKING LOW TO MID 80S FOR AFTERNOON HIGHS ON FRIDAY AS A SSW WIND TAKES HOLD AHEAD OF THE APPROACHING COLD FRONT. AS FAR AS PRECIP CHANCES, DECIDED TO STAY W/THE DAYCREW`S THINKING OF DRY CONDITIONS FOR THURSDAY W/A CHANCE OF SHOWERS(30-40%) BY LATE FRIDAY AFTERNOON AND THIS WILL MAINLY BE ACROSS THE FAR W AND NW AREAS. SOME OF THE INSTABILITY PARAMETERS SUCH AS 0-6KM SHEAR, PWATS 1.5+" AND AN INVERTED V TYPE SOUNDING SUGGEST THE THREAT FOR TSTMS. 0-6KM SHEAR IS FORECAST FROM BOTH THE NAM AND GFS TO BE AROUND 35 KTS W/GOOD DIRECTIONAL AND SPEED SHEAR NOTED. DECIDED TO KEEP THE MENTION OF TSTMS IN THERE FOR LATE FRIDAY AFTERNOON. THE DAYCREW CAN ASSESS THIS FURTHER W/THE LATER MODEL GUIDANCE. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... THE COLD FRONT IS FORECAST TO MOVE ACROSS THE REGION FRIDAY NIGHT AND STALL ACROSS THE DOWNEAST REGION ON SATURDAY INTO SATURDAY NIGHT AS IT BECOMES ALIGNED W/THE UPPER FLOW. A WEAK SURFACE LOW IS SHOWN BY THE GFS AND ECMWF TO DEVELOP ON THE FRONT WHICH WOULD KEEP THE RAIN GOING A WHILE LONGER. THE ECMWF IS FURTHER N W/THE RAIN SHIELD WHILE THE GFS AND ITS ENSEMBLE KEEP THE RAIN ACROSS THE CENTRAL AND DOWNEAST REGION. DECIDED ON A CONSENSUS FOR THIS CYCLE YIELDING 60% FOR SHOWERS/RAIN ACROSS THE DOWNEAST AND COAST AND 20-40% FURTHER N. A COOLER AIRMASS IS EXPECTED SUNDAY INTO EARLY NEXT WEEK AS HIGH PRES SLIDE SE FROM CENTRAL CANADA. IT WILL BE A NOTICEABLE CHANGE AS DAYTIME TEMPERATURES ARE FORECAST TO BE SOME 10-15 DEGREES COOLER THAN THEY HAVE BEEN THIS WEEK. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: EXPECT IFR/MVFR CONDITIONS THIS MORNING AS SHOWERS AND THUNDERSTORMS MOVE THROUGH WITH A COLD FRONT....IMPROVING TO VFR LATER THIS MORNING AS HIGH PRESSURE AND DRIER AIR MOVES IN FROM THE WEST. SHORT TERM: VFR THURSDAY INTO FRIDAY. THE CAVEAT TO THIS WILL BE THE POTENTIAL FOR SOME SHALLOW FOG ESPECIALLY THURSDAY MORNING THANKS IN PART TO THE RAINFALL THAT OCCURRED EARLIER. SOME TERMINALS ESPECIALLY THE NORTHERN SITES COULD SEE A PERIOD OF MVFR OR PERHAPS IFR IN THE MORNING. PERIODS OF MVFR FOR THE NORTHERN TAF SITES W/A COLD FROPA FRIDAY EVENING WHILE IFR/MVFR IS POSSIBLE ACROSS KBGR AND KBHB FRIDAY NIGHT INTO SATURDAY. && .MARINE... NEAR TERM: HAVE USED THE NAM12 TO INITIALIZE THE SUSTAINED WIND GRIDS. FOR WAVES: A SOUTHERLY FETCH CONTINUES TO DEVELOP ACROSS THE GULF OF MAINE AHEAD OF AN APPROACHING COLD FRONT. MOST OF THIS FETCH IS OVER THE GULF OF MAINE WHERE COLDER AIR TEMPERATURE IS SUPPRESSING WIND SPEEDS REACHING SURFACE. THIS FETCH IS GENERATING THE PRIMARY WAVE SYSTEM (SOUTH 3 FEET/7-8 SECONDS). WAVE MODELS APPEAR TOO HIGH DUE TO BOUNDARY CONDITIONS... SO HAVE INITIALIZED WAVES WITH NEAR SHORE WAVE MODEL AND WILL ADJUST LOWER BY 20 PERCENT. WAVE FIELD ALSO ACCOMPANIED BY SECONDARY WAVE GROUP FROM SOUTHEAST 1 FOOT/9-10 SECONDS. SHORT TERM: NO HEADLINES FORESEEN UNTIL LATER FRIDAY NIGHT INTO SATURDAY W/ A COLD FRONT SLIDING ACROSS THE WATERS. ATTM, DECIDED TO STAY W/GUSTS TO 25 KTS AND SEAS CLIMBING TO 6 FT BY EARLY SATURDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HASTINGS/MIGNONE SHORT TERM...HEWITT LONG TERM...HEWITT AVIATION...HASTINGS/MIGNONE/HEWITT MARINE...HASTINGS/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS DULUTH MN
1009 AM CDT WED SEP 3 2014 .UPDATE... ISSUED AT 950 AM CDT WED SEP 3 2014 UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG WENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING. THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS AFFECTING DEVELOPMENT IN THE NORTH. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT WED SEP 3 2014 THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH. THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH CENTRAL FORECAST AREA. A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN BOUNDARY. THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST 30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES. MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK OF STORMS. THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 350 AM CDT WED SEP 3 2014 INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH- CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES OVER THE NRN WISCONSIN ZONES BY MIDNIGHT. THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE AIR MASS. THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP. LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C. FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER CONVECTION. IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 650 AM CDT WED SEP 3 2014 A WARM FRONT WILL LIFT OVER THE FORECAST AREA TODAY...BRINGING LOWERING CEILINGS AND INCREASING THUNDER CHANCES THROUGH THE AFTERNOON AND EVENING. BY 06Z...WIDESPREAD MVFR/IFR CONDITIONS WILL BE FOUND AFTER 06Z AS LOW CLOUDS AND SCATTERED SHOWERS AND THUNDERSTORMS ARE FOUND ACROSS THE REGION. HAVE BROUGHT IN LIFR CONDITIONS TO KDLH AFTER 06Z...AS WINDS TURN OUT OF THE EAST AND ELEVATED DEW POINTS ALLOW FOR FOG/-DZ. && .PRELIMINARY POINT TEMPS/POPS... DLH 75 62 70 55 / 60 70 40 10 INL 76 57 72 46 / 40 50 50 30 BRD 78 64 76 50 / 70 80 20 20 HYR 78 66 83 52 / 40 80 60 20 ASX 79 63 81 53 / 50 70 70 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...STEWART SHORT TERM...GROCHOCINSKI LONG TERM...GRANING AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS HASTINGS NE
639 AM CDT WED SEP 3 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 417 AM CDT WED SEP 3 2014 UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER 70S. THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT /THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER OF THE CWA. TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN MILD IN THE MID 60S TO MID 70S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 417 AM CDT WED SEP 3 2014 MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION. WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES. AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED STATES. MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING THE COLD FRONT FARTHER SOUTH. INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY LATE EVENING FRIDAY NIGHT INTO SATURDAY. THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A WARM FRONT. ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME COOLER WEATHER FOR WEDNESDAY. THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN RIGHT NOW. FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE DAY AFTER A COLD FRONT PASSAGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 635 AM CDT WED SEP 3 2014 MAIN FORECAST CONCERN COMES THIS MORNING...AS RESTRICTIONS WITH AT LEAST CEILINGS SEEMS LIKELY AS AN AREA OF LOW LEVEL STRATUS EXPANDS ACROSS THE AREA. SURROUND OBS SHOWING CEILINGS LESS THAN 1000FT...AND HAVE THOSE CONDITIONS IN AT BOTH TERMINALS THROUGH MID MORNING...LIFTING A BIT FOR THE LATE MORNING HOURS. MODELS SUGGEST VFR CONDITIONS ARE EXPECTED TO RETURN THIS AFTERNOON...WILL SEE HOW THAT PANS OUT. ADJUSTMENTS TO THE TIMING OF CEILING IMPROVEMENTS MAY BE NEEDED. ONGOING PRECIPITAITON SLIDING IN FROM THE WEST AT THIS POINT LOOKS TO REMAIN SOUTH OF THE TERMINAL AREAS. WINDS THROUGH THE PERIOD WILL REMAIN SOUTHERLY...INCREASING WITH TIME...WITH SPEEDS THIS AFTERNOON IN THE 15 TO 25 MPH RANGE...GUSTS NEAR 30 MPH POSSIBLE. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADO LONG TERM...HEINLEIN AVIATION...ADO
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EDT WED SEP 3 2014 .SYNOPSIS...A SURFACE TROUGH WILL BE LOCATED OVER CENTRAL NORTH CAROLINA THIS AFTERNOON AS A COLD FRONT REMAINS JUST TO OUR NORTH. HIGH PRESSURE THEN WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1055 AM WEDNESDAY... THE LATEST SURFACE ANALYSIS SHOWED A SURFACE FRONT OVER NORTHERN VIRGINIA WITH SURFACE TROUGHS CLOSE TO THE VIRGINIA BORDER EXTENDING WEST TO EAST...AND OVER THE WESTERN PART OF CENTRAL NORTH CAROLINA. WIND SHEAR WAS WEAK AND SHOULD REMAIN SO THROUGH THE REST OF THE DAY...WITH RAP FORECAST 0-3KM VALUES ON THE ORDER OF 10KT OR LESS. THE LATEST SPC MESOANALYSIS SHOWED GOOD CIN OVER THE WESTERN PIEDMONT WITH INSTABILITY...TO 2000J/KG...ALONG THE IMMEDIATE COAST. THE RAP FORECASTS THIS CIN...ASSOCIATED WITH A LOW-LEVEL CAP AND GOOD DEW POINT SPREADS SUCH AS NOTED ON THE 12Z KGSO SOUNDING... ERODING THIS AFTERNOON AROUND 20Z. WHILE IN THE MID-LEVELS THERE SHOULD BE A WEAK SHEAR AXIS AND VORTICITY CLOSER TO THE VIRGINIA BORDER THIS AFTERNOON...BETTER LOW-LEVEL FORCING IS EXPECTED IN SURFACE TROUGHINESS CLOSER TO THE COASTAL PLAIN WHERE THE INSTABILITY SHOULD ALSO BE GREATER...ON THE ORDER OF 1500J/KG THIS AFTERNOON BASED ON RAP SOUNDINGS. THE RAP FORECASTS THE BETTER LIFT IN THAT AREA AS WELL...GRADUALLY PROPAGATING WEST IN THE LIGHT WINDS AND WEAK SHEAR. THE VARIETIES OF HRRR WRF GUIDANCE LEAN TOWARD INITIAL DEEP CONVECTIVE DEVELOPMENT TOWARD INTERSTATE 95 GRADUALLY PROPAGATING NORTHWEST...STRUGGLING TO MAKE IT INTO THE TRIAD WHERE OVERALL STABILITY SHOULD BE GREATER. FOR THE MORNING UPDATE... DELAYED THE ONSET OF ISOLATED TO SCATTERED POPS AND TRENDED ANY TO LATE IN THE DAY AND INTO THIS EVENING OVER THE NORTHWEST PIEDMONT. GIVEN DCAPE FORECAST AT A MAXIMUM AROUND 700J/KG THIS AFTERNOON... AN ISOLATED STORM COULD PRODUCE A STRONG WIND GUST...BUT INSTANCES OF SUCH SHOULD BE PULSE-LIKE IN WEAK SHEAR AND WEAK WINDS ALOFT. WITH GOOD SUN THROUGH THE MORNING AND A FAST RISE TO TEMPERATURES... IN SEVERAL LOCATIONS RAISED MAXES A DEGREE OR TWO...FOR HIGHS OF 90 TO 95. APPARENT TEMPERATURES...LIKE IN THE HWO...SHOULD BE WITHIN A DEGREE OR TWO OF 100 EAST OF ABOUT U.S. 1. CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AS OF 305 AM WEDNESDAY... THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN THE UPPER 60S AND LOWER 70S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY... THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK. A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM WATERS. FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS... BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO) H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE 80S. SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH HIGHS IN THE UPPER 70S TO LOWER 80S. TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... AS OF 1055 AM WEDNESDAY... VFR CONDITIONS ARE EXPECTED TO PREVAIL THIS AFTERNOON THROUGH THIS EVENING OUTSIDE OF DEEP CONVECTION. SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS AFTERNOON IN THE VICINITY OF A SURFACE TROUGH OVER THE AREA. WEAK STEERING FLOW AND THE POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME CONVECTION AT ANY SPECIFIC TAF SITE...BUT THE PRESENCE OF THE TROUGH LENDS BETTER CHANCES TO KFAY...KRWI AND KRDU. HOWEVER...CONFIDENCE IS FAIRLY HIGH THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON AND EVENING. A LIGHT SOUTHERLY WIND IS EXPECTED TO REDEVELOP TONIGHT...WHICH MAY INDUCE PATCHY STRATUS ACROSS THE AREA BY THURSDAY MORNING. OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE THIS WEEKEND INTO EARLY NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF/BLS SHORT TERM...BLS LONG TERM...MWS AVIATION...DJF/BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
730 AM EDT WED SEP 3 2014 .SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 305 AM WEDNESDAY... A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING. LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT. HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE MAIN STORM THREATS. CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AS OF 305 AM WEDNESDAY... THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN THE UPPER 60S AND LOWER 70S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY... THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK. A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM WATERS. FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS... BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO) H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE 80S. SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH HIGHS IN THE UPPER 70S TO LOWER 80S. TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 730 AM WEDNESDAY... ONCE THE BRIEF MVFR VSBYS AT KRWI IMPROVE...LIKELY BY 13Z...VFR CONDITIONS ARE EXPECTED TO PREVAIL OUTSIDE OF CONVECTION. SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS AFTERNOON IN THE VICINITY OF A SURFACE TROUGH OVER THE AREA. WEAK STEERING FLOW AND THE POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME CONVECTION AT ANY SPECIFIC TAF SITE...BUT THE PRESENCE OF THE TROUGH LENDS BETTER CHANCES TO KFAY...KRWI AND KRDU. HOWEVER... CONFIDENCE IS FAIRLY HIGH THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING. A LIGHT SOUTHERLY WIND IS EXPECTED TO REDEVELOP TONIGHT...WHICH MAY INDUCE PATCHY STRATUS ACROSS THE AREA BY THURSDAY MORNING. OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE THIS WEEKEND INTO EARLY NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BSD/WSS NEAR TERM...BLS SHORT TERM...BLS LONG TERM...MWS AVIATION...BLS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1011 AM CDT WED SEP 3 2014 .UPDATE... ISSUED AT 1001 AM CDT WED SEP 3 2014 MAIN FOCUS REMAINS ON WHAT WILL HAPPEN LATER TODAY IN TERMS OF SEVERE CONVECTION IN FAR NORTHEASTERN SD..WEST CENTRAL-CENTRAL MN AND HOW FAR NORTH WILL IT REACH. INCOMING 12Z DATA FROM NAM AND LATEST RAP/HRRR MODELS INDICATE ABOUT THE SAME SCENERIO WITH EVENTUAL NORTHWARD ADVANCE OF CONVECTION ZONE THAT IS NOW FROM BTWN BROOKINGS AND WATERTOWN SD TOWARD THE TWIN CITIES...WITH IT REACHING NEAR THE SISSETON-ALEXANDRIA-LONG PRAIRIE MN LINE EARLY TO MID AFTERNOON. HOWEVER HRRR MAY BE A TAD FAST IN SPREADING IT NORTH AS ABUNDANCE OF CLOUD COVER MAY KEEP TRUE WARM FRONT A BIT SOUTH YET OF PROGGED POSITION...WHICH FROM THE HRRR IS ROUGHLY NR A WATERTOWN-WILMAR LINE AT 21Z. REGARDLESS...MAIN THREAT FOR ANY PRECIP NOT REACHING THE FAR SOUTHEASTERN FCST TIL THIS AFTN WITH INCREASING CHANCES BY LATE AFTN. RISK OF SEVERE THERE...THOUGH HIGHEST SEVERE PARAMETERS REMAIN A TAD SOUTH. OTHERWISE DRY OVER MUCH OF NW MN INTO ERN ND (OUTSIDE OF FAR SOUTHEASTERN CORNER). MAIN UPPER LOW TO LIVE EAST-NORTHEAST WITH CONVECTION DEVELOPING ALONG FRONT THIS EVENING IN FAR WESTERN ND AND THEN SOME CHANCE OF A COMPLEX MOVING EAST INTO ERN ND OVERNIGHT. LATEST RAP SHOWS QUITE IMPRESSIVE SHOWALTERS DOWN TO -10C 06Z-07Z INTO SE ND IN THE LEFT QUAD OF A 40-45 KT LOW LEVEL JET OVER EASTERN SD. SO IN THAT RESPECT MODELS MAYBE UNDERESTIMATING PRECIP TONIGHT. AFTER COORD WITH WFO BIS....ONLY REAL CHANGE TO FCST IS TO REMOVE THAT BLENDED POP ZONE IN DEVILS LAKE REGION WE HAD LATE THIS AFTN. NOTHING THERE TIL PAST 00Z. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 315 AM CDT WED SEP 3 2014 CONVECTION CHANCES...SEVERITY...AND TIMING WILL BE THE HEADACHES FOR THE SHORT TERM. STRONG SHORTWAVE TROUGH CURRENTLY DIGGING INTO THE PAC NW WILL QUICKLY MOVE INTO MT DURING THE DAY TODAY. SFC LOW PRESSURE OVER MT/WY WILL MOVE INTO THE DAKTOAS BY THIS AFTERNOON. CONVECTION FIRING ALONG THE NOSE OF THE LOW LEVEL JET OVER EASTERN SOUTH DAKOTA WILL CONTINUE NORTHEASTWARD AND MAY CLIP PART OF GRANT COUNTY LATER THIS MORNING. THUS...KEPT SOME LOW POPS GOING FOR THIS MORNING BUT THINK THE BETTER PRECIP CHANCES WILL HOLD OFF UNTIL LATER THIS AFTERNOON AS THE SFC LOW COMES EAST AND A WARM FRONT LIFTS INTO OUR FAR SOUTHERN COUNTIES. MODELS BRING UP QUITE A LOT OF MOISTURE WITH THE FRONT...WITH THE NAM SHOWING LOW 70S DEW POINTS IN OUR FAR SOUTH BY AFTERNOON. HOWEVER...GIVEN THE CURRENT READINGS OVER NEB THINK THAT THE ECMWF/GFS WITH DEW POINTS IN THE 60S WILL BE MORE IN LINE WITH REALITY. WITH WINDS ALOFT INCREASING AHEAD OF THE SHORTWAVE BULK SHEAR VALUES WILL BE PUSHING 50 KTS BY THIS AFTERNOON. SEVERE WEATHER WILL BE A POSSIBILITY...PARTICULARLY IN THE LOW LEVEL SHEAR AREA NEAR THE WARM FRONT. TONIGHT...THE SHORTWAVE TROUGH WILL MOVE INTO WESTERN ND...WITH THE SFC LOW ENTERING THE EASTERN DAKOTAS. THERE WILL BE SOME GOOD FRONTOGENESIS IN NORTHEASTERN SD AND OUR FAR SOUTHERN COUNTIES AS THE SFC LOW PUSHES EAST. GFS/NAM BREAK OUT PRECIP OVER THE SISSETON HILLS REGION INTO OUR SOUTHERN COUNTIES BUT THE ECMWF AND GEM ARE DRIER. WARM MID LEVEL TEMPS MAY KEEP A LID ON CONVECTION BUT THINK THAT THERE IS ENOUGH CHANCE FOR STORMS ALONG THAT SOUTHERN SFC LOW CENTER THAT CONTINUED TO KEEP SOME CHANCE POPS GOING. FURTHER NORTH...THE MAIN SHORTWAVE WILL BE MOVING INTO SOUTHERN CANADA AND THE MODELS SHOW SOME HEAVY QPF ALONG THE DEFORMATION ZONE TO THE NORTHWEST OF A NORTHERN LOW CENTER DEVELOPING ALONG THE CANADIAN BORDER. CONTINUED TO KEEP HIGH POPS GOING FOR THE NORTH IN AREAS THAT WILL BE CLOSER TO THE MAIN UPPER SHORTWAVE. CENTRAL COUNTIES WILL SEE LESSER CHANCES THAN THE FAR NORTH AND FAR SOUTH...BUT KEPT SOME SLIGHT POPS. THURSDAY...THE MAIN SHORTWAVE WILL MOVE OFF INTO SOUTHERN CANADA...WITH THE SFC LOW MOVING INTO THE GREAT LAKES. THERE WILL BE SOME GOOD ISENTROPIC DOWNGLIDE MOVING INTO OUR WESTERN COUNTIES AND THEN ACROSS THE CWA FROM MID MORNING INTO THE AFTERNOON. THERE COULD BE SOME WRAP AROUND PRECIP IN THE NORTH...BUT MODELS ARE SHOWING A TREND OF A DRY SLOT COMING IN FOR MUCH OF THE CWA. WINDS WILL BE A GREATER CONCERN WITH STRONG COLD AIR ADVECTION AND A TIGHT PRESSURE GRADIENT. CONTINUED TO KEEP SPEEDS BELOW ADVISORY CRITERIA FOR NOW BUT WILL MONITOR. THE NORTHWEST WINDS WILL BRING IN SOME COOLER AIR AND OUR NORTHWESTERN COUNTIES COULD STAY IN THE LOW 60S WHILE THE SOUTHEAST WILL BE WARMER WITH A LATER FRONTAL PASSAGE. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 315 AM CDT WED SEP 3 2014 THURSDAY NIGHT THROUGH FRIDAY NIGHT...SOME LINGERING SHOWERS WILL BE POSSIBLE THURSDAY NIGHT AS THE SFC LOW PULLS AWAY INTO THE GREAT LAKES. TEMPS SHOULD BE FAIRLY CHILLY IN THE 40S AS CLOUDS BEGIN TO CLEAR OUT AND HIGH PRESSURE BUILDS INTO THE PLAINS. WEST TO SOUTHWESTERLY WINDS WILL BRING IN SOME SLIGHTLY WARMER AIR FOR FRIDAY WHICH WILL HELP KEEP TEMPS IN THE UPPER 60S...BUT ANOTHER REINFORCING SHORT WAVE WILL BE DIGGING INTO THE PLAINS FRIDAY AND FRIDAY NIGHT AND BRING DOWN ANOTHER FRONTAL BOUNDARY. A FEW OF THE MODELS BREAK OUT SOME PRECIP WITH THIS REINFORCING FRONT...BUT THINK THAT THERE WILL NOT BE MUCH MOISTURE AVAILABLE SO KEPT THE FORECAST DRY FOR NOW. TEMPS FRIDAY NIGHT WILL BE MODERATED BY CLOUD COVER BUT WILL STILL BE MAINLY IN THE 40S THANKS TO COLD AIR ADVECTION. SATURDAY THROUGH TUESDAY...PERIOD STARTS WITH A NORTHWEST FLOW AND ENDS WITH THE NEXT SIGNIFICANT UPPER WAVE. FOR THE FIRST HALF OF THIS PERIOD...INTO SUNDAY... THE WEATHER SHOULD BE PRECIPITATION FREE. TIMING OF PRECIPITATION BECOMES PROBLEMATIC MONDAY AND TUESDAY...AS RAW MODEL QPF IS PRETTY SCANT INTO 12Z MONDAY. HOWEVER...WITH INCREASING SOUTHWEST FLOW ALOFT AND LOW - MID LEVEL WAA AND INCREASINGLY COUPLED 200 MB JET STRUCTURE ARGUES FOR BROAD LIFT. WITH THE GUIDANCE SUGGESTING ANOMALOUSLY HIGH...FOR SEPTEMBER...TD AND PWATS APPROACHING +2 SIGMA CANNOT ARGUE AGAINST BLENDED POPS. OVERALL TEMPERATURES AS FORECAST ARE PRETTY CLOSE TO EARLY SEPTEMBER MEDIAN VALUES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 641 AM CDT WED SEP 3 2014 PATCHY FOG HAS IMPACTED KTVF AND KGFK AT TIMES THIS MORNING...GOING RAPIDLY UP AND DOWN IN VIS. INCLUDED TEMPO GROUP AT KGFK TO ACCOUNT FOR PATCHY FOG BUT THINK THAT ALL SITES WILL SEE FOG DISSIPATE BY 13 OR 14Z. VFR CONDITIONS WILL CONTINUE FOR MUCH OF THE PERIOD WITH EAST WINDS AROUND 10 KTS. WARM FRONT MOVING IN FROM THE SOUTH MAY BRING SOME STORMS NEAR THE KFAR AREA...AND THERE WILL BE ANOTHER ROUND OF STORMS POSSIBLE AFTER 06Z IN THE NORTHERN TAF SITES. JUST INCLUDED VCTS MENTION AT KFAR...KDVL...AND KGFK FOR NOW. THERE COULD BE SOME MVFR CIGS LATE IN THE PERIOD WITH MORE MOISTURE IN THE REGION...BUT JUST INCLUDED THE LOWER CIGS AT KDVL AND KBJI FOR NOW. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...RIDDLE SHORT TERM...JR LONG TERM...JR/EWENS AVIATION...JR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT WED SEP 3 2014 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 338 AM CDT WED SEP 3 2014 MAIN CONCERN FOCUSED ON SEVERE POTENTIAL TONIGHT AND AGAIN THURSDAY NIGHT. WATER VAPOR OR BIG PICTURE VIEW SHOWS A FAIRLY HIGH ZONAL FLOW ACROSS THE NORTHERN CONUS. A WEAK EMBEDDED MID-LEVEL TROUGH WAS NOTED EJECTING NORTHEAST OUT OF WY INTO WESTERN SD. AT THE SURFACE...A WARM FRONT EXTENDED FROM SOUTHWEST SD INTO EASTERN NEB. LIFT AHEAD OF THE WAVE AND WARM FRONT WAS PRODUCING A SMALL AREA OF SHOWERS/THUNDERSTORMS OVER EASTERN SD/FAR SOUTHWEST MN PER LATEST REGIONAL RADAR MOSAIC. OTHERWISE...CLOSER TO HOME...HIGH PRESSURE WAS PRODUCING MOSTLY CLEAR SKIES ACROSS THE FORECAST AREA WITH TEMPERATURES RANGING FROM THE LOWER 50S A NEAR 60 DEGREES. FOR TODAY...SURFACE CYCLOGENESIS WILL CONTINUE TO TAKE SHAPE OVER MT/NORTHERN PLAINS. THIS WILL LIFT THE AFOREMENTIONED WARM FRONT OUT OF THE CENTRAL PLAINS INTO SOUTHERN MN. ALSO...STRENGTHENING SOUTHERLY FLOW WILL PRODUCE INCREASING MOISTURE TRANSPORT/ISENTROPIC LIFT INTO THE AREA. THIS IS EXPECTED TO FUEL ELEVATED AND SCATTERED SHOWERS/THUNDERSTORMS MAINLY ALONG AND NORTH OF I-90 THROUGH THE DAY. PLAN ON HIGHS IN THE 75-85 DEGREE RANGE. AS WE GO INTO TONIGHT...STRENGTHENING LOW PRESSURE MOVING FROM THE DAKOTAS INTO WESTERN MN WILL DRIVE THE WARM FRONT FARTHER NORTHEAST...NEAR THE I-94 CORRIDOR BY MORNING. THIS IS WHERE IT GETS COMPLICATED. 850MB MOISTURE TRANSPORTS CRANKS UP SIGNIFICANTLY WITH VECTORS POINTED DIRECTLY INTO THE AREA. AT THE SAME TIME...STRONG CAP SETS UP ALONG THE MISSISSIPPI RIVER AS EVIDENCED BY THE NAM/GFS BUFKIT SOUNDINGS. EXPECTING A COMPLEX OF THUNDERSTORMS TO FIRE SOMEWHERE ALONG I-94 BETWEEN THE TWIN CITIES AND SAINT CLOUD MN BY THIS EVENING ON THE EDGE OF THIS CAP AND ON THE NOSE OF THE MOISTURE TRANSPORT. FORWARD PROPAGATING CORFIDI VECTORS BRING THIS COMPLEX SOUTHEAST AND THEN ON A MORE SOUTHERLY TRAJECTORY ONCE IT GETS EAST OF THE MISSISSIPPI...AGAIN ON THE EDGE OF THE CAP AND IN THE CORRIDOR OF VERY RICH MOISTURE FEED. THIS COMPLEX WILL HAVE TO BE WATCHED CLOSELY FOR SEVERE THREAT. EARLY ON IN THE EVENING...MODEL CONSENSUS 0-3KM MUCAPE OF 2500- 4000J/KG AND 0-6KM BULK SHEAR OF 40-50KT WILL BE SUFFICIENT FOR SUPERCELL DEVELOPMENT MAINLY ACROSS EAST CENTRAL MN INTO NORTHWEST WI FOR LARGE HAIL POTENTIAL...AND TORNADO THREAT IF STORMS GET ROOTED IN THE BOUNDARY LAYER. AS MENTIONED...THEN EXPECTING THIS THUNDERSTORM COMPLEX TO FOLLOW CORFIDI VECTORS...TAKING INTO DIRECTLY OVER OUR AREA MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. BY THEN MOST OF THESE STORMS WILL BE ELEVATED IN NATURE. WITH PRECIPITABLE WATER VALUES OF 1.5-2 INCHES OFF THE NAM AND GFS...HEAVY RAINFALL BECOMES THE MAIN THREAT ALONG WITH DAMAGING WIND POTENTIAL. SOME LARGE HAIL WILL ALSO BE POSSIBLE. CANNOT RULE OUT THE POSSIBILITY OF SOME FLASH FLOODING IF THERE IS ANY REPETITIVE CONVECTION OVER NAY ONE AREA...BUT SYSTEM SEEMS OVERALL PRETTY PROGRESSIVE IN NATURE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 338 AM CDT WED SEP 3 2014 MODELS SHOW DEEP AREA OF LOW PRESSURE MOVING NORTH OUT OF WESTERN MN INTO WESTERN ONTARIO BY LATE AFTERNOON. AS A RESULT...WARM FRONT WILL PUSH NORTHEAST THROUGH THE AREA WITH A VERY WARM/HUMID/CAPPED DAY IN STORE. HIGH TEMPERATURES ARE EXPECTED TO PUSH INTO THE 85-91 DEGREE RANGE WITH DEW POINTS IN THE LOWER 70S. THIS WILL RESULT IN HEAT INDICES OF 90-100. AS THE LOW CONTINUES TO LIFT NORTHEAST INTO ONTARIO A COLD FRONT WILL THEN PUSH THROUGH THE AREA THURSDAY NIGHT. INITIALLY THE AREA REMAINS UNDER THE INFLUENCE OF THE STRONG CAP...BUT CONVECTION IS EXPECTED TO EVENTUALLY FIRE IN THE EVENING AFTER 6 PM...AS THE FRONT/ALONG WITH MID-LEVEL TROUGH MOVES IN WITH COOLING ALOFT...WHICH SHOULD THEN BE ENOUGH TO OVERCOME THE CAP. SOME OF THESE STORMS SHOULD BE COME SEVERE WITH DAMAGING WIND AND LARGE HAIL BEING THE MAIN THREATS. FOR FRIDAY INTO THE WEEKEND... DRIER/COOLER AIR MOVES INTO THE AREA FRIDAY BEHIND THE FRONT. LOOK FOR HIGHS IN THE UPPER 60S TO THE MIDDLE 70S. COOL AND DRY CONDITIONS LOOK TO PERSIST THROUGH THE WEEKEND AS CANADIAN HIGH PRESSURE DOMINATES THE MID-SECTION OF THE CONUS/UPPER MISSISSIPPI RIVER VALLEY REGIONS. HIGHS SATURDAY AND SUNDAY STAY IN THE UPPER 60S/LOWER 70S WITH OVERNIGHT LOWS DIPPING INTO THE 40S AND LOWER 50S. FOR MONDAY INTO TUESDAY... HIGH PRESSURE DRIFTS OFF TO THE EAST AS LOW PRESSURE APPROACHES FROM THE PLAINS. AS A RESULT...PLAN ON SHOWER/THUNDERSTORM CHANCES TO INCREASE THROUGH THE PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 617 AM CDT WED SEP 3 2014 AREA OF ELEVATED SHOWERS AND STORMS OVER SOUTHWEST MINNESOTA IN ASSOCIATION WITH A WEAK SHORT WAVE TROUGH. THE 03.09Z RAP SUGGESTS THE WAVE WILL CONTINUE TO MOVE EAST TOWARD THE AREA WHILE THE MID LEVEL MOISTURE TRANSPORT LIFTS NORTHEAST. THE 03.00Z HI-RES ARW AND 03.09Z HRRR BOTH SUGGEST THE ACTIVITY WILL LIFT NORTHEAST WITH THE MOISTURE TRANSPORT AND MISS BOTH TAF SITES. FEEL THE BULK OF THE ACTIVITY SHOULD MISS THE TAF SITES BUT WILL CARRY A VCTS AT KRST IN THE EVENT THAT THE MOVEMENT ENDS UP BEING MORE TO THE EAST. AFTER THAT...WARM AIR ALOFT WILL RAPIDLY BUILD OVER THE AREA TODAY PUTTING A CAP IN PLACE THAT SHOULD ALLOW THE NEXT ROUND OF CONVECTION TO FORM NORTH OF BOTH TAF SITES LATE THIS AFTERNOON INTO THE EVENING. ALL THE MESO MODELS SUGGEST THE ACTIVITY WILL THEN STAY NORTH OF THE AREA THROUGH THE OVERNIGHT...BUT THE 03.00Z ECMWF SUGGEST SOME SOUTHEAST MOVEMENT ALONG THE EDGE OF THE CAP CLOSE TO THE BACKWARD PROPAGATING CORFIDI VECTORS. IF THIS CAN OCCUR...THERE IS A CHANCE SOME ACTIVITY COULD MOVE DOWN THE MISSISSIPPI RIVER INTO WESTERN WISCONSIN AND WILL CONTINUE TO CARRY A VCTS IN THE LATE EVENING FOR THIS AT KLSE BUT THINK IT WILL MISS KRST...IF IT CAN TURN SOUTHEAST. WITH THE STRONG LOW LEVEL JET FEEDING INTO THE CONVECTIVE ACTIVITY...LOW LEVEL WIND SHEAR SHOULD BE PRESENT AND HAVE INCLUDED THIS OUTSIDE OF THE THUNDER TIME IN THE EVENING AND OVERNIGHT HOURS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...04
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
350 PM EDT WED SEP 3 2014 .DISCUSSION... CURRENT/TONIGHT... LATEST RUC SHOWS THE AXIS OF THE ERLY WAVE HAS MOVED LITTLE SINCE DAYBREAK WITH THE H85-H50 AXIS AS WELL AS ITS H100-H70 REFLECTION STILL LURKING JUST OFF THE E FL COAST AS OF MID AFTN. RADAR SHOWING SCT SHRAS OVER THE INTERIOR THAT WILL PUSH W OF THE CWA WELL BEFORE SUNSET. UPSTREAM...A SECOND BAND OF SHRAS/TSTMS OVER THE ATLC WILL PROVIDE NEXT ROUND OF PRECIP FOR EAST CENT FL. WHILE MID LVL ENERGY IS PRESENT IN THE FORM OF A BAND OF DEEP LYR VORT BTWN THE NRN BAHAMAS AND THE E FL COAST...THE BULK OF THE ENERGY REMAINS WELL S AND E OF LAKE OKEECHOBEE. RUC ANALYSIS INDICATES MID LVL LAPSE RATES HAVE CHANGED LITTLE SINCE THE MRNG RAOBS WITH H85-H50 READINGS HOLDING ARND 5.5C-KM. UPSTREAM MOISTURE REMAINS PLENTIFUL WITH H100-H70 MEAN RH VALUES AOA 80PCT...H85-H50 VALUES AOA 60PC...BUT A REFLECTION OF THE DRY TONGUE LINGERS OVER THE SPACE COAST WITH H85-H50 RH DECREASING TO AOB 40PCT. CHC SHRAS ALONG THE COAST OVERNIGHT AND OKEECHOBEE COUNTY OVERNIGHT...INCREASING N TO S TO REFLECT THE CURRENT MOISTURE PROFILE. WILL KEEP SLGT CHC SHRAS IN FOR THE INTERIOR N OF OKEECHOBEE COUNTY THRU 02Z TO ACCOUNT FOR ONGOING PRECIP...BUT GIVEN THE LACK OF EITHER DYNAMIC OR THERMODYNAMIC INSTABILITY...THESE SHOULD COLLAPSE ONCE THE LOSS OF DIURNAL HEATING KICKS IN. MIN TEMPS IN THE L/M70S. THU-FRI... THE ERLY WAVE WILL ROTATE AROUND THE WRN FLANK OF THE ATLC RIDGE AND ALLOW DEEP MOISTURE TO INCREASE ACRS CENTRAL FL WITH PWATS RECOVERING TO ARND 1.8" ON THU...AND BTWN 2.0"-2.2" ON FRI. WITH THE CWA GAINING THE ASCENDING SIDE OF THE WAVE...NUMEROUS SHRA AND SCT TSRAS SHOULD FORM EACH DAY. LCL HEAVY RAIN MAY OCCUR WITH STRONGER THAT DVLP IN THE AFTERNOON AS H50 TEMPS COOL TO ARND -8C. PRECIP CHANCES SLIGHTLY LOW ON FRI AS THE WAVE BEGINS TO PUSH INTO THE GOMEX WITH THE ATLC RIDGE REBUILDING IN ITS WAKE. DESPITE INCREASING CLOUD COVER...SE LOW LVL WINDS WILL GENERATE AFTN MAX TEMPS TO PUSH MAX TEMPS INTO THE U80S/L90S AREAWIDE. ONSHORE FLOW AND SFC DEWPOINTS IN THE L/M70S WILL KEEP MIN TEMPS A FEW DEGS ABV AVG...GENERALLY IN THE M/U70S. EXTENDED...(PREV DISC) SAT-SUN...THE ATLANTIC RIDGE WILL EXTEND WEST ACROSS CENTRAL FL OVER THE WEEKEND WITH A RETURN A MORE TYPICAL SEA BREEZE REGIME WITH LESS INFLUENCE FROM UPPER LEVEL FEATURES AS THE MID LVL RIDGE REBUILDS OVER THE STATE. THE EAST COAST SEA BREEZE SHOULD MOVE INLAND EACH AFTERNOON WITH THE HIGHEST SHOWER/THUNDERSTORM COVERAGE WEST OF I-95 INTO THE INTERIOR BY THE MID TO LATE AFTERNOON HOURS. RAIN CHANCES AROUND 30 CLOSE TO THE COAST AND 40-50 PERCENT FOR THE INTERIOR. HIGHS AROUND 90 COAST TO AROUND 93 FOR THE INTERIOR ZONES. MON-WED...APPEARS THE MID LVL RIDGE WILL REMAIN IN CONTROL EARLY NEXT WEEK WITH LOW LVL SE WINDS FORECAST. THIS SHOULD AGAIN FAVOR THE INTERIOR FOR AFTERNOON STORMS WITH THE INLAND MOVING DIFFUSE EAST COAST BREEZE. MOISTURE LEVELS LOOK TO DIMINISH SOME SO WILL FORECAST RAIN CHANCES 30 PCT COASTAL TO 40 PCT FOR THE INTERIOR. NOT MUCH DAY TO DAY CHANGE IN HIGH TEMPS EXPECTED WITH AROUND 90 COAST TO THE LOWER 90S INLAND. && .AVIATION... THRU 04/00Z...E/SE SFC WND 8-12KTS...SW OF KDED-KVRB SCT MVFR SHRAS/ISOLD IFR TSRAS WITH PSBL SFC WND G25-30KTS...NE OF KDED-KVRB ISOLD MVFR SHRAS. BTWN 04/00-04/12Z...SE SFC WNDS AOB 5KTS...CHC MVFR SHRAS E OF KOMN-KOBE. AFT 04/12Z...E/SE SFC WNDS 5-10KTS... PREVAILING CIGS BTWN FL100-120...CHC MVFR SHRAS ALL SITES. && .MARINE... TONIGHT...LIGHT TO GENTLE ERLY BREEZE BCMG SE AS THE AXIS OF AN ERLY WAVE PUSHES ACRS THE LCL ATLC...SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE WITH DOMINANT PDS AOA 8SEC. SCT SHRAS AND ISOLD TSRAS... MORE NUMEROUS GULF STREAM AND NEARSHORE WATERS S OF SEBASTIAN INLET. THU-FRI...GENTLE TO MODERATE SERLY BREEZE WILL PREVAIL AS THE ERLY WAVE ROTATES AROUND THE WRN FLANK OF THE ATLC RIDGE. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE...DOMINANT PDS ARND 8SEC THU... DECREASING TO 7SEC N OF ST. LUCIE INLET AND 4-5SEC S OF THE INLET AS THE SE BREEZE PLACES THE LCL ATLC UNDER THE SHADOW OF GRAND BAHAMA ISLAND. NMRS SHRAS AND SCT TSTMS THU...BCMG SCT/ISOLD ON FRI AS THE WAVE LIFTS INTO THE GOMEX. SAT-SUN... SFC/BNDRY LYR WINDS WILL SHIFT MORE TO THE S ARND 10KTS AS THE ATLC RIDGE REBUILDS OVER THE FL STRAITS IN THE WAKE OF THE DEPARTING WAVE. SEAS 2-3FT AREAWIDE. SHRA/TSTM CHANCES DECREASING AS SLIGHTLY DRIER AND MORE STABLE AIR PUSHES INTO THE LCL ATLC. && .PRELIMINARY POINT TEMPS/POPS... DAB 74 89 75 88 / 30 50 30 40 MCO 74 93 75 92 / 20 50 20 40 MLB 75 90 77 89 / 40 60 30 40 VRB 72 90 76 89 / 50 60 30 30 LEE 74 93 76 91 / 20 50 20 40 SFB 75 93 76 92 / 20 50 20 40 ORL 75 93 76 92 / 20 50 20 40 FPR 74 89 75 88 / 50 60 30 30 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ FORECAST/AVIATION...BRAGAW RADAR/IMPACT WX.....CRISTALDI
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
625 PM EDT WED SEP 3 2014 .SYNOPSIS... HIGH PRESSURE WILL PREVAIL INTO THIS WEEKEND. A COLD FRONT WILL STALL AND DISSIPATE NORTH OF THE REGION BY LATE WEEK...THEN A STRONGER COLD FRONT COULD ADVANCE INTO THE REGION LATE IN THE WEEKEND OR EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... WATER VAPOR IMAGERY AND RAP VORTICITY DATA SUGGEST THE AREA IS UNDER THE INFLUENCE OF BROAD DIFFERENTIAL NEGATIVE VORTICITY ADVECTION. THIS HAS RESULT IN A GENERAL LACK OF CONVECTIVE ACTIVITY THIS AFTERNOON...DESPITE ADEQUATE INSTABILITY. THERE IS STILL A RISK OF AN ISOLATED SHOWER OR TSTMS ACROSS FAR INTERIOR SOUTHEAST GEORGIA AHEAD OF THE SEA BREEZE...BUT ANY ACTIVITY THAT FIRES WILL BE SHORT LIVED. ADJUSTED POPS TO 20 PERCENT IN THIS AREA WITH DRY CONDITIONS ELSEWHERE THROUGH THE EVENING HOURS. LATER TONIGHT...ISOLATED SHOWERS/TSTMS COULD MOVE ONSHORE IN THE ONSHORE FLOW/COASTAL CONVERGENCE REGIME. THE LATEST RUNS OF THE RAP AND H3R SUPPORT THIS SCENARIO. MAINTAINED SLIGHT CHANCE POPS OVER THE COASTAL WATERS AND BEACHES. LOWS WILL RANGE FROM THE LOWER-MID 70S INLAND TO THE MID-UPPER 70S AT THE COAST AND DOWNTOWN CHARLESTON. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... A MODERATELY STRONG...DEEP LAYER RIDGE OF HIGH PRESSURE WILL REMAIN ANCHORED ACROSS THE ATLANTIC AND SOUTHEAST STATES THROUGH AT LEAST FRIDAY. BY SATURDAY...THE WESTERN PORTION OF THE RIDGE BEGINS TO ERODE/BREAK DOWN AS A BROAD UPPER TROUGH BUILDS INTO THE GREAT LAKES STATES AND NORTHEAST U.S.. THIS UPPER TROUGH WILL ALSO PUSH A WEAK COLD FRONT TO JUST NORTHWEST OF THE REGION BY LATE SATURDAY. THURSDAY...MODELS HAVE BEEN CONSISTENTLY SHOWING A NARROW BAND OF MID AND UPPER LEVEL DRYING TO MOVE INTO THE AREA FOR THE FIRST PART OF THE DAY AROUND THE NW FRINGE OF THE UPPER/TUTT LOW...CURRENTLY STRETCHING FROM THE BAHAMAS...SOUTHWEST INTO CUBA. THIS DRIER AIR WILL HELP TO LIMIT CONVECTIVE COVERAGE. THUS...HAVE KEPT SLIGHT CHANCE POPS MOST AREAS...EXCEPT LOW END CHANCE EXTREME INTERIOR WHERE MAX HEATING COMBINES WITH A LATE DAY SEA BREEZE. MAX TEMPS STILL IN THE LOWER 90S MOST AREAS...AND COMBINED WITH MODERATE LOW LEVEL HUMIDITY... WILL RESULT IN MAX HEAT INDICES OF 100-103. ANY CONVECTION SHOULD DIE DOWN AFTER SUNSET...THEN PARTLY CLOUDY WITH LOWS IN THE 70S. FRIDAY...BETTER DEEP LAYER MOISTURE ADVANCES BACK IN FROM THE SOUTHEAST ON THE NW EDGE OF THE UPPER/TUTT LOW WELL TO THE SOUTH IN THE GULF OF MEXICO. EXPECT SCATTERED MAINLY AFTERNOON AND EARLY EVENING SHOWERS/THUNDERSTORMS...WITH BEST COVERAGE LIKELY INLAND. HIGHS AROUND 90 TO THE LOWER 90S. GUIDANCE TRIES TO HOLD ONTO POPS ALL NIGHT FRIDAY NIGHT...BUT STILL FEEL CONVECTION WILL BE MAINLY DIURNALLY FORCED. TO LEAN MORE TOWARD GUIDANCE AND TO BETTER COLLABORATE WITH SURROUNDING OFFICES...HAVE KEPT SLIGHT CHANCE OVER LAND AND CHANCE OVER WATER/ATLANTIC REGION. LOWS AGAIN IN THE 70S. SATURDAY...DEEP LAYER MOISTURE REMAINS HIGH WITH PRECIPITABLE WATER VALUES OVER 2 INCHES. NAM SHOWING A WEAK SURFACE LOW MOVING UP THE COAST FROM FL TO OFF SC COAST. OTHER MODELS MAINLY SHOW A WEAK INVERTED SURFACE TROUGH. THE DETAILS OF THE SURFACE FEATURES ARE STILL UNCERTAIN. HOWEVER...GIVEN SLIGHTLY LOWER UPPER HEIGHTS AND SUFFICIENT TROPICAL MOISTURE...EXPECT AT LEAST SCATTERED CONVECTION...AND WOULD NOT BE SURPRISED IF POPS NEED TO BE RAISED MORE WITH LATER FORECASTS. HIGH TEMPERATURES AROUND 90 TO THE LOWER 90S...BUT MAY BE LOWER IF CONVECTIVE COVERAGE ENDS UP BEING HIGHER THAN CURRENTLY FORECASTED. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... A SHIFT IN THE PATTERN WILL BRING ABOUT IMPROVING RAIN CHANCES INTO THE EARLY PART OF NEXT WEEK WITH COOLER TEMPERATURES RESULTING. HEIGHTS WILL FALL ALOFT AS THE AFOREMENTIONED NORTHERN STREAM TROUGH MOVES PAST. THIS WILL DRAG A COLD FRONT INTO THE AREA SOMETIME SUNDAY...LINGERING IN THE VICINITY THROUGH MONDAY BEFORE DISSIPATING THEREAFTER. PWATS WILL INCREASE TO OVER 2 INCHES AND THE CONVERGENCE WITHIN THE BOUNDARY IS EXPECTED TO RESULT IN MUCH BETTER COVERAGE OF SHOWERS AND THUNDERSTORMS SUNDAY...SUNDAY NIGHT...AND INTO MONDAY. POPS HAVE BEEN INCREASED INTO THE 50 PERCENT RANGE. BY THE LATTER PORTION OF THE FORECAST...CONFIDENCE IS A BIT LOWER AS THE MODELS SHOW HIGH PRESSURE TO THE NORTHEAST BUILDING IN WITH THE REMNANT BOUNDARY SOMEWHERE ALONG THE COAST OR JUST OFFSHORE. IN SHORT...THE LONG TERM PERIOD FEATURES INCREASING RAIN CHANCES AND COOLER TEMPERATURES. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... VFR. EXTENDED AVIATION OUTLOOK...VFR EXPECTED TO PREVAIL THROUGH FRIDAY. ONLY ISOLATED TO SCATTERED AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED BOTH TERMINALS WITH BRIEF PERIODS OF FLIGHT RESTRICTIONS POSSIBLE. RAIN CHANCES MAY INCREASE SATURDAY AND SUNDAY AS EVEN DEEP TROPICAL MOISTURE TRIES TO MOVE FROM THE SOUTH INTO THE REGION...AND INTERACTS WITH AN APPROACHING COLD FRONT LATE WEEKEND AND EARLY NEXT WEEK. && .MARINE... TONIGHT THROUGH SUNDAY...HIGH PRESSURE WILL CONTINUE TO BE THE PRIMARY FEATURE THROUGH THE END OF THE PERIOD. A COLD FRONT WILL BEGIN TO APPROACH THE LOCAL WATERS LATE IN THE WEEKEND...BUT WILL NOT HAVE A SIGNIFICANT EFFECT ON WINDS/SEAS. THE PREVAILING FLOW WILL CONTINUE TO BE SOUTH TO SOUTHEASTERLY WITH SPEEDS LESS THAN 15 KT. PERIODS OF STRONGER FLOW WILL BE POSSIBLE ALONG THE LAND/SEA INTERFACE WITH THE SEA BREEZE...AS WELL IN MODEST NOCTURNAL SURGING. SEAS WILL CONTINUE TO BE 1-3 FT...HIGHEST BEYOND 20 NM. && .TIDES/COASTAL FLOODING... ASTRONOMICAL TIDE HEIGHTS WILL GRADUALLY INCREASE THROUGH THE WEEK AS WE APPROACH A PERIGEAN FULL MOON NEXT WEEK AND EARLY NEXT WEEK. EXTRA-TROPICAL STORM SURGE MODEL RUNS HAVE BEEN TRENDING TOWARD INCREASING TIDE LEVELS THROUGH THE WEEK...WITH THE LATEST RUN NOW PREDICTING TIDES JUST ABOVE 7 FT MLLW FOR CHARLESTON /MARGINAL COASTAL FLOODING/...BUT REMAIN JUST BELOW 9 FT FOR FT. PULASKI. GIVEN THIS LATEST FORECAST...LOOKS LIKE THE BEST THREAT FOR MINOR COASTAL FLOODING WOULD BE THE CHARLESTON/SC COAST BY SATURDAY. IF THE ONSHORE FLOW IS STRONGER THAN CURRENTLY PREDICTED...MINOR COASTAL FLOODING COULD BEGIN AS EARLY AS FRIDAY EVENING. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST
AREA FORECAST DISCUSSION
NWS TOPEKA KS
348 PM CDT Wed Sep 3 2014 .SHORT TERM...(This Evening through Thursday) Issued at 345 PM CDT WED SEP 3 2014 Water vapor loop shows relatively zonal flow across the Central Plains with weak disturbances moving through. One vort max appears to be along the border between northwest KS and southwest NE and seems to be associated with thunderstorm cluster moving into eastern Nebraska. HRRR has been the only model that developed convection into central KS this evening, and has done so for the last several runs. RAP just recently has forecast precip into same general area in the next several hours. Meanwhile, all other models are keeping central and eastern KS dry tonight. Confidence is not high enough that HRRR is right, and thus have continued with POPs below 20% for tonight in forecast area. Good pressure gradient across the area tonight will maintain southerly winds of 10 to 15 kts most areas. This should help keep minimum temperatures up in the lower to middle 70s. On Thursday, more sunshine than today and warm temperature aloft will allow highs to reach the mid 90s most areas. Combined with dewpoints generally in the upper 60s to lower 70s, peak afternoon heat indices should reach the 100 to 105 range. Frontal boundary approaches northwest corner of our CWA around 21Z on Thursday, thus the chance of late afternoon thunderstorms is continued in that area. .LONG TERM...(Thursday Night through Wednesday) Issued at 345 PM CDT WED SEP 3 2014 Models are in good agreement that the cold front will traverse the county warning area Thursday night into midday Friday...although the GFS is the fastest. Convection that develops along and front Thursday night will have the greatest impact with coverage and rainfall amounts across the northern 1/3 of the cwa through sunrise Friday as the front advances southeastward. Will range pops from likely in the northwest counties to only a slight chance in the far southeast near Garnett...then keep higher end chance pops all areas on Friday along and behind the frontal passage and the approach of a shortwave trough from the central high plains. This wave will move east of the cwa early Saturday with diminishing chances for rain north to south as much drier air overspreads the area. With the frontal passage/cold air advection/clouds and precip in the area will see much cooler highs from the upper 60s around Belleville to the middle 80s south of I 35. This will set the stage for lows in the 50s most areas Friday night and Saturday night. With the dry air in place and high pressure center over the area...will keep the area dry late Saturday through Sunday with highs in the 70s both days. With the flow aloft slowly transitioning from northwest on Saturday to a more unsettled west to southwest flow into next week. As it does...the chances for more thunderstorms will increase and so will the high temperatures ahead of the next front which is expected by early Wednesday as a larger scale upper trough moves into the plains. Will introduce pops in the north central by Sunday night and then across the remainder of the cwa Monday into Wednesday. Highs will generally be in the 80s...cooling slightly into the upper 70s and lower 80s by Wednesday. && .AVIATION...(For the 18Z TAFs through 18Z Thursday Afternoon) Issued at 1221 PM CDT WED SEP 3 2014 CIGS rising and clouds are scattering out so VFR conditions expected through the forecast period. Southerly winds should increase and be gusty into early evening. Very small chance that some thunderstorms could develop across central KS this evening and move toward MHK overnight. But chances too low for TEMPO or PROB30 in TAF. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GDP LONG TERM...63 AVIATION...GDP
AREA FORECAST DISCUSSION
NWS GOODLAND KS
244 PM MDT WED SEP 3 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 150 PM MDT WED SEP 3 2014 WARM SOUTHWESTERLY MID LEVEL FLOW AND DEEP MIXING HAS RESULTED IN SIGNIFICANTLY ABOVE NORMAL TEMPERATURES TODAY WELL INTO THE 90S AT MOST LOCATIONS. SOME HIGH BASED CU HAS FORMED EARLY THIS AFTERNOON MAINLY OVER EASTERN COLORADO AND A FEW ISOLATED SHOWERS/STORMS ARE POSSIBLE LATE THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE THE FAR SOUTHERN PORTION OF THE FORECAST AREA WHERE RAP SOUNDINGS SHOW DEEP MIXING BUT MORE BOUNDARY LAYER MOISTURE AND INSTABILITY THAN FURTHER NORTH. AN UPPER LEVEL SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY OVER THE NORTHERN ROCKIES MOVING EASTWARD. THIS SHORTWAVE WILL MOVE INTO THE NORTHERN PLAINS TONIGHT FORCING SURFACE CYCLOGENESIS TO OUR NORTH. TIGHTENING SURFACE PRESSURE GRADIENT WILL RESULT IN INCREASING WINDS BACKING TO MORE OF A SOUTHERLY DIRECTION THIS EVENING AND INTO THE NIGHT. SUFFICIENT MIXING AND LESS LOW LEVEL MOISTURE THAN PREVIOUS NIGHTS SHOULD PRECLUDE A FOG THREAT OVERNIGHT. A COLD FRONT WILL EVOLVE FROM LEE TROUGHING AND SURGE SOUTHWARD ACROSS THE FORECAST AREA TOMORROW MORNING BRINGING COOLER TEMPERATURES. WARM/MOIST ADVECTION OVER SURFACE BOUNDARY WILL RESULT IN SHOWERS AND THUNDERSTORMS INCREASING BY LATE IN THE DAY TOMORROW ACROSS THE SOUTHWESTERN PORTION OF THE AREA AND ESPECIALLY JUST AFTER THE SHORT TERM PERIOD. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 242 PM MDT WED SEP 3 2014 THURSDAY NIGHT AND FRIDAY WIDESPREAD RAINFALL...HEAVY AT TIMES...LOOKS VERY LIKELY FOR THE AREA. THURSDAY NIGHT MID AND UPPER LEVEL MIXING RATIOS INCREASE AHEAD OF A COMPACT UPPER LEVEL SHORT WAVE TROUGH THAT WILL MOVE ACROSS THE AREA THROUGH THE NIGHT. AHEAD OF THE TROUGH ELEVATED CAPE DEVELOPS AS THE JET AT 750MB NOSES IN THE FROM THE SOUTHEAST...AND PROGRESSES NORTHWEST ACROSS MOST OF THE AREA THROUGH THE NIGHT. WITH ISENTROPIC AS WELL AS SYNOPTIC LIFT OCCURRING ALONG THE NOSE OF THIS JET...ANTICIPATE ELEVATED STORMS TO DEVELOP ALONG IT BY EARLY EVENING. ELEVATED CAPE ABOVE 750MB MAY BE AS HIGH AS 2500J/KG ALONG AND SOUTHEAST OF THE NOSE OF THE 750MB JET...WITH INSTABILITY DECREASING DRAMATICALLY NORTHWEST OF THE NOSE. IF STORMS ARE ABLE TO TAP INTO THE HIGHER INSTABILITY HAIL UP TO 2 INCHES IN DIAMETER WILL BE POSSIBLE DUE TO DEEP LAYER SHEAR OF 35KTS. HOWEVER FURTHER NORTHWEST OF THE JET NOSE HAIL SIZE WILL TAPPER OFF DRAMATICALLY DUE TO LITTLE TO NO ELEVATED CAPE. PLACED SEVERE WORDING IN THE FORECAST WHERE SEVERE STORMS WILL BE MOST LIKELY. IN ADDITION TO THE LARGE HAIL...MEAN STORM MOTION WILL BE AROUND 20MPH AND WILL BE PARALLEL TO THE NOSE OF THE 750MB JET. THIS WILL LEAD TO SLOW MOVING TRAINING STORMS CAPABLE OF PRODUCING HEAVY RAINFALL. ANTICIPATE STORMS TO START OFF AS MORE SUPER CELLULAR IN THE EVENING WHEN ELEVATED CAPE IS HIGHEST. OVERNIGHT AS THE ELEVATED INSTABILITY DIMINISHES AND ICE NUCLEI SEEDING FROM UPWIND STORMS OCCURS...BELIEVE THE HAIL SIZE WILL BECOME SMALLER THAN ONE INCH IN DIAMETER. HOWEVER HEAVY RAINFALL WILL BECOME MORE OF A THREAT. FURTHER NORTHWEST OF THE NOSE OF THE 750MB JET 700-500MB THETA-E LAPSE RATES INDICATE A CONVECTIVELY UNSTABLE ENVIRONMENT DESPITE THE LACK OF ELEVATED CAPE. WITH UPPER LEVEL SHORT WAVE TROUGH MOVING ACROSS MOST OF THE AREA THROUGH THE NIGHT DECIDED TO KEEP THE RAINFALL CHANCES GOING FOR THE REST OF THE AREA...WITH THE BEST CHANCE FOR RAINFALL ACTUALLY SHIFTING NORTH TOWARD THE NE BORDER OVERNIGHT FOLLOWING THE HIGHER 700-500MB MIXING RATIOS AND 700-500MB FRONTOGENESIS. ASIDE FROM THE WIDESPREAD RAINFALL...A SECOND SURGE OF COOLER AIR WILL MOVE INTO THE AREA FROM THE NORTH THROUGH THE NIGHT. FRIDAY MORNING THE UPPER LEVEL SHORT WAVE TROUGH FROM LAST NIGHT WILL EXIT THE AREA AS ANOTHER SHORT WAVE TROUGH DEEPENS OVER THE WESTERN PART OF THE AREA. MEANWHILE THE BAND OF 700-500MB FRONTOGENESIS STRENGTHENS THROUGH THE DAY AND MOVES EAST ACROSS THE AREA AHEAD OF THIS SECOND SHORT WAVE TROUGH. CAPE WILL BE AROUND 1000J/KG OR LESS SO DO NOT ANTICIPATE A SEVERE THREAT SINCE THE CAPE PROFILE WILL BE TALL AND NARROW WHICH FAVORS HEAVY RAINFALL. MEAN STORM MOTION WILL CONTINUE TO BE AROUND 20MPH ALSO FAVORING HEAVY RAINFALL. ANTICIPATE THE RAINFALL TO END FROM WEST TO EAST DURING THE AFTERNOON AS THE UPPER LEVEL SHORT WAVE TROUGH EXITS THE AREA. DUE TO THE COUPLE ROUNDS OF HEAVY RAINFALL POSSIBLE...A FLASH FLOOD WATCH MAY BE NEEDED BUT WILL HOLD OFF FOR NOW IN ORDER TO GET A GOOD HANDLE AS TO WHERE THE FLOODING THREAT WILL BE MOST LIKELY. FRIDAY EVENING THERE MAY BE SOME LINGERING SHOWERS OVER THE EASTERN PART OF THE AREA AS THE SHORT WAVE TROUGH MOVES EAST. DURING THE LATE EVENING AND OVERNIGHT HOURS ANOTHER LESS COMPACT UPPER LEVEL SHORT WAVE TROUGH WILL MOVE THROUGH THE AREA. CURRENTLY THE SOUTH HALF TO 1/3 HAS THE BEST LIFT AND INSTABILITY SO WILL HAVE THE HIGHER RAINFALL CHANCES THERE. SATURDAY THROUGH WEDNESDAY NUMEROUS UPPER LEVEL SHORT WAVE TROUGHS MOVE ACROSS THE AREA. TWO STRONGER SHORT WAVE TROUGHS WILL MOVE THROUGH MONDAY AFTERNOON AND MONDAY NIGHT. AS A RESULT WILL HAVE HIGHER RAINFALL CHANCES FOR MONDAY NIGHT. OTHERWISE LOW RAINFALL CHANCES ARE FORECAST FOR VARIOUS PARTS OF THE AREA AS THE WEAKER UPPER LEVEL DISTURBANCES MOVE THROUGH. TEMPERATURES FOR THE PERIOD WILL START OFF COOLER THAN NORMAL THEN GRADUALLY WARM TO NEAR NORMAL AS THE COOLER AIR MASS MOVES EAST OF THE AREA. WEDNESDAY ANOTHER COLD FRONT WILL MOVE INTO THE AREA BRINGING BELOW NORMAL TEMPERATURES WITH IT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1136 AM MDT WED SEP 3 2014 LOW STRATUS HAS DEPARTED THE AREA LEAVING CLEAR SKIES. VFR CONDITIONS WILL PREVAIL THROUGH THE END OF THE TAF PERIOD. THE SURFACE LEE SIDE TROUGH WILL STRENGTHEN THIS EVENING AND WINDS SHOULD BACK SLIGHTLY TO A MORE SOUTHERLY DIRECTION AND INCREASE. GUSTS OVER 20 KNOTS ARE POSSIBLE THIS EVENING AND MUCH OF THE NIGHT...ESPECIALLY AT KGLD...BEFORE A PERIOD OF LIGHTER WINDS TOMORROW MORNING. BY MID MORNING A COLD FRONT WILL PASS THROUGH AND THE WINDS WILL SHIFT TO THE NORTH. GUSTS TO AROUND 25 KNOTS ARE EXPECTED THROUGH LATE MORNING IMMEDIATELY BEHIND THE FRONT. EXTENSIVE CLOUDS AND PRECIPITATION WILL HOLD OFF UNTIL WELL AFTER THE END OF THE TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BRB LONG TERM...JTL AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
150 PM MDT WED SEP 3 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 150 PM MDT WED SEP 3 2014 WARM SOUTHWESTERLY MID LEVEL FLOW AND DEEP MIXING HAS RESULTED IN SIGNIFICANTLY ABOVE NORMAL TEMPERATURES TODAY WELL INTO THE 90S AT MOST LOCATIONS. SOME HIGH BASED CU HAS FORMED EARLY THIS AFTERNOON MAINLY OVER EASTERN COLORADO AND A FEW ISOLATED SHOWERS/STORMS ARE POSSIBLE LATE THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE THE FAR SOUTHERN PORTION OF THE FORECAST AREA WHERE RAP SOUNDINGS SHOW DEEP MIXING BUT MORE BOUNDARY LAYER MOISTURE AND INSTABILITY THAN FURTHER NORTH. AN UPPER LEVEL SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY OVER THE NORTHERN ROCKIES MOVING EASTWARD. THIS SHORTWAVE WILL MOVE INTO THE NORTHERN PLAINS TONIGHT FORCING SURFACE CYCLOGENESIS TO OUR NORTH. TIGHTENING SURFACE PRESSURE GRADIENT WILL RESULT IN INCREASING WINDS BACKING TO MORE OF A SOUTHERLY DIRECTION THIS EVENING AND INTO THE NIGHT. SUFFICIENT MIXING AND LESS LOW LEVEL MOISTURE THAN PREVIOUS NIGHTS SHOULD PRECLUDE A FOG THREAT OVERNIGHT. A COLD FRONT WILL EVOLVE FROM LEE TROUGHING AND SURGE SOUTHWARD ACROSS THE FORECAST AREA TOMORROW MORNING BRINGING COOLER TEMPERATURES. WARM/MOIST ADVECTION OVER SURFACE BOUNDARY WILL RESULT IN SHOWERS AND THUNDERSTORMS INCREASING BY LATE IN THE DAY TOMORROW ACROSS THE SOUTHWESTERN PORTION OF THE AREA AND ESPECIALLY JUST AFTER THE SHORT TERM PERIOD. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 251 AM MDT WED SEP 3 2014 SEASONABLE PATTERN FOR THE FIRST WEEKEND OF SEPTEMBER WITH SOME LOW CHANCES FOR PRECIP AND HIGHS RANGING FROM THE LOW 70S TO MID 80S. ON THE SYNOPTIC SCALE AN UPPER RIDGE OVER WEST TEXAS/EAST NEW MEXICO WILL GRADUALLY WEAKEN OVER THE WEEKEND. MODELS IN GENERALLY GOOD AGREEMENT AT MID-LEVELS FOR A NORTHWEST TO ZONAL TO SOUTHWESTERLY FLOW OVER THE WEEKEND...THOUGH SIGNIFICANT DIFFERENCES DEVELOP BY LATE MONDAY ON THE TIMING OF MID-LEVEL SHORTWAVE TROUGHS. ECMWF SEEMS TO PREFER A MORE ORGANIZED TROUGH AXIS MOVING THROUGH THE CENTRAL HIGH PLAINS LATE MONDAY INTO EARLY TUESDAY...WHILE GFS DEPICTS MORE NUMEROUS WEAK IMPULSES WHICH MAKE IT MORE DIFFICULT TO FORECAST THE FINE-SCALE DETAILS. AT THE SURFACE HIGH PRESSURE WILL DEVELOP ACROSS THE CENTRAL AND NORTHERN PLAINS ON SATURDAY...DRIFTING EASTWARD INTO THE UPPER MIDWEST ON SUNDAY. A NORTH-SOUTH ORIENTED SURFACE TROUGH WILL DEVELOP NEAR THE KANSAS-COLORADO BORDER SUNDAY AND MONDAY RESULTING IN BREEZY CONDITIONS AND OFFERING A FOCUS FOR STORMS TO DEVELOP EACH DAY. SATURDAY AND SUNDAY...REDUCED POPS SIGNIFICANTLY IN COLLABORATION WITH NEIGHBORS AS IT APPEARS COLD FRONT WILL BE FARTHER SOUTH THAN PREVIOUSLY THOUGHT. WITH NO LARGE-SCALE FORCING IN PLAY IT LOOKS LIKE JUST A FEW DIURNALLY-DRIVEN SHOWERS/STORMS POSSIBLE ON SUNDAY AFTERNOON. ALSO...AS SFC HIGH PRESSURE MOVES EAST SATURDAY INTO SUNDAY THERE WILL BE LOW/MID LEVEL MOISTURE ADVECTION FROM THE SOUTHWEST LEADING TO A CLOUDY DAY TO START MONDAY...LIMITING HEATING AND THEREFOR FURTHER REDUCING THE LIKELIHOOD OF SHOWERS/STORMS ON SUNDAY. MONDAY/TUESDAY...BREEZY ON MONDAY WITH A SURFACE TROUGH DEVELOPING AS PREVIOUSLY MENTIONED. ECMWF CLEARLY BRINGS A MID-LEVEL SHORTWAVE TROUGH ACROSS THE REGION LATE MONDAY INTO TUESDAY WHILE THE DETERMINISTIC GFS JUST DEPICTS A SERIES OF SUBTLE IMPULSES MOVING FROMM EST TO EAST ACROSS THE ENTIRE GREAT PLAINS REGION. A NUMBER OF GEFS MEMBERS DEPICT A PATTERN SIMILAR TO THE ECMWF DURING THIS PERIOD...SO ULTIMATELY DECIDED TO KEEP THE TEENS TO 20S POPS. WITH SOUTHERLY LOW-LEVEL FLOW THROUGH THE SUNDAY/MONDAY/TUESDAY TIMEFRAME WILL SEE WARM AIR ADVECTION LEADING TO A WARMING TREND IN TEMPS...WITH HIGHS REACHING THE LOW TO MID 80S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1136 AM MDT WED SEP 3 2014 LOW STRATUS HAS DEPARTED THE AREA LEAVING CLEAR SKIES. VFR CONDITIONS WILL PREVAIL THROUGH THE END OF THE TAF PERIOD. THE SURFACE LEE SIDE TROUGH WILL STRENGTHEN THIS EVENING AND WINDS SHOULD BACK SLIGHTLY TO A MORE SOUTHERLY DIRECTION AND INCREASE. GUSTS OVER 20 KNOTS ARE POSSIBLE THIS EVENING AND MUCH OF THE NIGHT...ESPECIALLY AT KGLD...BEFORE A PERIOD OF LIGHTER WINDS TOMORROW MORNING. BY MID MORNING A COLD FRONT WILL PASS THROUGH AND THE WINDS WILL SHIFT TO THE NORTH. GUSTS TO AROUND 25 KNOTS ARE EXPECTED THROUGH LATE MORNING IMMEDIATELY BEHIND THE FRONT. EXTENSIVE CLOUDS AND PRECIPITATION WILL HOLD OFF UNTIL WELL AFTER THE END OF THE TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BRB LONG TERM...JJM AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1253 PM CDT WED SEP 3 2014 .UPDATE... ISSUED AT 1251 PM CDT WED SEP 3 2014 UPDATED FOR ONGOING THUNDERSTORMS IN THE ARROWHEAD. THESE STORMS DEVELOPED ALONG A LINE OF ACCAS IN THE AREA. UPDATE ISSUED AT 1229 PM CDT WED SEP 3 2014 UPDATED FOR AVIATION DISCUSSION BELOW. UPDATE ISSUED AT 1110 AM CDT WED SEP 3 2014 UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH PRECIP SLOWLY DRIFTING NORTH. UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014 UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG ENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING. THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS AFFECTING DEVELOPMENT IN THE NORTH. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT WED SEP 3 2014 THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH. THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH CENTRAL FORECAST AREA. A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN BOUNDARY. THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST 30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES. MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK OF STORMS. THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 350 AM CDT WED SEP 3 2014 INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH- CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES OVER THE NRN WISCONSIN ZONES BY MIDNIGHT. THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE AIR MASS. THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP. LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C. FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER CONVECTION. IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1229 PM CDT WED SEP 3 2014 LINE OF THUNDERSTORMS TO THE SOUTH WILL SLOWLY ENCROACH UPON THE REGION THROUGH THE AFTERNOON. MODEL GUIDANCE IS KEEPING THE STORMS FROM TRACKING TOO FAR NORTH...BUT WILL CLIP BRD AND DLH AND PUSH ACROSS HYR THROUGH THE EVENING. A SECONDARY LINE OF WEAKER CONVECTION WILL DEVELOP OVER NE MN THIS AFTERNOON AND LINGER OVER THE REGION TONIGHT AS WELL. WILL LIKELY SEE FOG DEVELOP BEHIND THE SYSTEM WITH LIFR CIGS/VSBYS AND SOME -DZ POSSIBLE ALONG THE NORTH SHORE AND AROUND DLH. A FEW LIGHT RAIN SHOWERS ARE POSSIBLE THURSDAY MORNING. && .PRELIMINARY POINT TEMPS/POPS... DLH 75 62 70 55 / 60 70 40 10 INL 76 57 72 46 / 40 50 50 30 BRD 78 64 76 50 / 70 90 20 20 HYR 78 66 83 52 / 50 90 60 20 ASX 79 63 81 53 / 50 70 70 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...STEWART SHORT TERM...GROCHOCINSKI LONG TERM...GRANING AVIATION...BJT
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1229 PM CDT WED SEP 3 2014 .UPDATE... ISSUED AT 1229 PM CDT WED SEP 3 2014 UPDATED FOR AVIATION DISCUSSION BELOW. UPDATE ISSUED AT 1110 AM CDT WED SEP 3 2014 UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH PRECIP SLOWLY DRIFTING NORTH. UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014 UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG ENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING. THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS AFFECTING DEVELOPMENT IN THE NORTH. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT WED SEP 3 2014 THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH. THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH CENTRAL FORECAST AREA. A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN BOUNDARY. THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST 30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES. MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK OF STORMS. THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 350 AM CDT WED SEP 3 2014 INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH- CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES OVER THE NRN WISCONSIN ZONES BY MIDNIGHT. THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE AIR MASS. THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP. LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C. FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER CONVECTION. IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1229 PM CDT WED SEP 3 2014 LINE OF THUNDERSTORMS TO THE SOUTH WILL SLOWLY ENCROACH UPON THE REGION THROUGH THE AFTERNOON. MODEL GUIDANCE IS KEEPING THE STORMS FROM TRACKING TOO FAR NORTH...BUT WILL CLIP BRD AND DLH AND PUSH ACROSS HYR THROUGH THE EVENING. A SECONDARY LINE OF WEAKER CONVECTION WILL DEVELOP OVER NE MN THIS AFTERNOON AND LINGER OVER THE REGION TONIGHT AS WELL. WILL LIKELY SEE FOG DEVELOP BEHIND THE SYSTEM WITH LIFR CIGS/VSBYS AND SOME -DZ POSSIBLE ALONG THE NORTH SHORE AND AROUND DLH. A FEW LIGHT RAIN SHOWERS ARE POSSIBLE THURSDAY MORNING. && .PRELIMINARY POINT TEMPS/POPS... DLH 75 62 70 55 / 60 70 40 10 INL 76 57 72 46 / 40 50 50 30 BRD 78 64 76 50 / 70 80 20 20 HYR 78 66 83 52 / 40 80 60 20 ASX 79 63 81 53 / 50 70 70 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...GROCHOCINSKI LONG TERM...GRANING AVIATION...BJT
AREA FORECAST DISCUSSION
NWS DULUTH MN
1111 AM CDT WED SEP 3 2014 .UPDATE... ISSUED AT 1110 AM CDT WED SEP 3 2014 UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH PRECIP SLOWLY DRIFTING NORTH. UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014 UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG WENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING. THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS AFFECTING DEVELOPMENT IN THE NORTH. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT WED SEP 3 2014 THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH. THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH CENTRAL FORECAST AREA. A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN BOUNDARY. THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST 30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES. MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK OF STORMS. THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 350 AM CDT WED SEP 3 2014 INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH- CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES OVER THE NRN WISCONSIN ZONES BY MIDNIGHT. THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE AIR MASS. THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP. LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C. FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER CONVECTION. IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 650 AM CDT WED SEP 3 2014 A WARM FRONT WILL LIFT OVER THE FORECAST AREA TODAY...BRINGING LOWERING CEILINGS AND INCREASING THUNDER CHANCES THROUGH THE AFTERNOON AND EVENING. BY 06Z...WIDESPREAD MVFR/IFR CONDITIONS WILL BE FOUND AFTER 06Z AS LOW CLOUDS AND SCATTERED SHOWERS AND THUNDERSTORMS ARE FOUND ACROSS THE REGION. HAVE BROUGHT IN LIFR CONDITIONS TO KDLH AFTER 06Z...AS WINDS TURN OUT OF THE EAST AND ELEVATED DEW POINTS ALLOW FOR FOG/-DZ. && .PRELIMINARY POINT TEMPS/POPS... DLH 75 62 70 55 / 60 70 40 10 INL 76 57 72 46 / 40 50 50 30 BRD 78 64 76 50 / 70 80 20 20 HYR 78 66 83 52 / 40 80 60 20 ASX 79 63 81 53 / 50 70 70 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...STEWART SHORT TERM...GROCHOCINSKI LONG TERM...GRANING AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1234 PM CDT WED SEP 3 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 417 AM CDT WED SEP 3 2014 UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER 70S. THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT /THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER OF THE CWA. TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN MILD IN THE MID 60S TO MID 70S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 417 AM CDT WED SEP 3 2014 MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION. WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES. AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED STATES. MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING THE COLD FRONT FARTHER SOUTH. INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY LATE EVENING FRIDAY NIGHT INTO SATURDAY. THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A WARM FRONT. ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME COOLER WEATHER FOR WEDNESDAY. THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN RIGHT NOW. FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE DAY AFTER A COLD FRONT PASSAGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1229 PM CDT WED SEP 3 2014 PERSISTENT MVFR CIGS THIS MORNING ARE EXPECTED TO DISSIPATE OVER THE NEXT FEW HOURS AS SATELLITE IMAGERY IS CONTINUING TO SHOW THIS AREA OF CLOUD COVER SLOWLY ERODING. OTHERWISE...EXPECT MAINLY CLEAR SKIES ONCE THE STRATUS DOES BURN OFF...WITH OCCASIONALLY GUSTY SOUTHERLY WINDS TO 25 KTS OR SO. OVERNIGHT...EXPECT THE POSSIBILITY OF SOME MARGINAL WIND SHEAR AS THE LOW LEVEL JET INCREASES...AND INCLUDED THIS MENTION AT BOTH SITES AS WELL. A STRONG COLD FRONT IS THEN EXPECTED TO CROSS THE TERMINALS BETWEEN 04/15Z-04/18Z...AND INDICATED A WIND SHIFT AHEAD OF THIS FRONT TOWARDS THE TAIL END OF THE VALID TAF PERIOD. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADO LONG TERM...HEINLEIN AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS RALEIGH NC
125 PM EDT WED SEP 3 2014 .SYNOPSIS...A SURFACE TROUGH WILL BE LOCATED OVER CENTRAL NORTH CAROLINA THIS AFTERNOON AS A COLD FRONT REMAINS JUST TO OUR NORTH. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1055 AM WEDNESDAY... THE LATEST SURFACE ANALYSIS SHOWED A SURFACE FRONT OVER NORTHERN VIRGINIA WITH SURFACE TROUGHS CLOSE TO THE VIRGINIA BORDER EXTENDING WEST TO EAST...AND OVER THE WESTERN PART OF CENTRAL NORTH CAROLINA. WIND SHEAR WAS WEAK AND SHOULD REMAIN SO THROUGH THE REST OF THE DAY...WITH RAP FORECAST 0-3KM VALUES ON THE ORDER OF 10KT OR LESS. THE LATEST SPC MESOANALYSIS SHOWED GOOD CIN OVER THE WESTERN PIEDMONT WITH INSTABILITY...TO 2000J/KG...ALONG THE IMMEDIATE COAST. THE RAP FORECASTS THIS CIN...ASSOCIATED WITH A LOW-LEVEL CAP AND GOOD DEW POINT SPREADS SUCH AS NOTED ON THE 12Z KGSO SOUNDING... ERODING THIS AFTERNOON AROUND 20Z. WHILE IN THE MID-LEVELS THERE SHOULD BE A WEAK SHEAR AXIS AND VORTICITY CLOSER TO THE VIRGINIA BORDER THIS AFTERNOON...BETTER LOW-LEVEL FORCING IS EXPECTED IN SURFACE TROUGHINESS CLOSER TO THE COASTAL PLAIN WHERE THE INSTABILITY SHOULD ALSO BE GREATER...ON THE ORDER OF 1500J/KG THIS AFTERNOON BASED ON RAP SOUNDINGS. THE RAP FORECASTS THE BETTER LIFT IN THAT AREA AS WELL...GRADUALLY PROPAGATING WEST IN THE LIGHT WINDS AND WEAK SHEAR. THE VARIETIES OF HRRR WRF GUIDANCE LEAN TOWARD INITIAL DEEP CONVECTIVE DEVELOPMENT TOWARD INTERSTATE 95 GRADUALLY PROPAGATING NORTHWEST...STRUGGLING TO MAKE IT INTO THE TRIAD WHERE OVERALL STABILITY SHOULD BE GREATER. FOR THE MORNING UPDATE... DELAYED THE ONSET OF ISOLATED TO SCATTERED POPS AND TRENDED ANY TO LATE IN THE DAY AND INTO THIS EVENING OVER THE NORTHWEST PIEDMONT. GIVEN DCAPE FORECAST AT A MAXIMUM AROUND 700J/KG THIS AFTERNOON... AN ISOLATED STORM COULD PRODUCE A STRONG WIND GUST...BUT INSTANCES OF SUCH SHOULD BE PULSE-LIKE IN WEAK SHEAR AND WEAK WINDS ALOFT. WITH GOOD SUN THROUGH THE MORNING AND A FAST RISE TO TEMPERATURES... IN SEVERAL LOCATIONS RAISED MAXES A DEGREE OR TWO...FOR HIGHS OF 90 TO 95. APPARENT TEMPERATURES...LIKE IN THE HWO...SHOULD BE WITHIN A DEGREE OR TWO OF 100 EAST OF ABOUT U.S. 1. CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AS OF 305 AM WEDNESDAY... THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN THE UPPER 60S AND LOWER 70S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY... THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK. A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM WATERS. FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS... BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO) H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE 80S. SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH HIGHS IN THE UPPER 70S TO LOWER 80S. TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 125 PM WEDNESDAY... A MODERATELY MOIST AND UNSTABLE AIR MASS WILL SUPPORT THE DEVELOPMENT OF SCATTERED CONVECTION LATE THIS AFTERNOON THROUGH THIS EVENING. THE CONVECTION WILL MOST LIKELY DEVELOP INITIALLY IN THE VICINITY OF KFAY AND KGSB. OUTFLOWS FROM THIS AREA OF CONVECTION WILL TRIGGER ADDITIONAL CONVECTION IN THE VICINITY OF KRWI AND KRDU PRIOR TO SUNSET. ISOLATED TO SCATTERED CONVECTION MAY ALSO OCCUR IN VICINITY OF KINT AND KGSO BY THIS EVENING. EXPECT BRIEF INSTANCES OF MVFR/IFR CEILING AND VISIBILITIES IN PROXIMITY OF THE STORMS. AN ISOLATED WIND GUSTS NEAR 40KTS MAY ALSO OCCUR. BULK OF CONVECTION WILL DIMINISH BEFORE MIDNIGHT. EXPECT AREAS OF MVFR/IFR CEILINGS TO DEVELOP PRIOR TO SUNRISE WITH THE NEAR TERM MODELS FAVORING THE PIEDMONT/KINT-KGSO-KRDU TERMINALS WITH THE GREATEST LIKELIHOOD OF ADVERSE AVIATION WEATHER CONDITIONS. MVFR CEILINGS APPEAR TO BE A GOOD PROBABILITY FOR MOST SITES EARLY THURSDAY MORNING WITH CEILINGS LIFTING INTO THE LOW END VFR CATEGORY BY 16Z. ANOTHER ROUND OF SCATTERED THUNDERSTORMS IS EXPECTED THURSDAY AFTERNOON WITH THE GREATEST PROBABILITY OVER THE NORTHERN PIEDMONT INCLUDING KGSO...KINT AND KRDU. EXPECT MAINLY VFR CONDITIONS FRIDAY AND SATURDAY WITH A PERIOD OF EARLY MORNING LOW CLOUDS AND FOG ANTICIPATED EACH DAY....AND ISOLATED CONVECTION EACH AFTERNOON. AN APPROACHING COLD FRONT WILL INCREASE THE THREAT FOR SCATTERED SHOWERS AND THUNDERSTORMS SUNDAY AND MONDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF/BLS SHORT TERM...BLS LONG TERM...MWS AVIATION...WSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
332 PM CDT WED SEP 3 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 319 PM CDT WED SEP 3 2014 CONCERN REMAINS HOW FAR NORTH CONVECTION GETS INTO SOUTHEASTERN FCST AREA LATE THIS AFTN/EVE AND HOW MUCH CONVECTION/PRECIP DEVELOPS IN WRN ND THIS EVE AND MOVES EAST OVERNIGHT. RAP/HRRR AND NAM12 HAVE BEEN DOING REASONABLE IN THEIR DEPICTION OF CONVECTION IN CNTRL MN NORTH OF THE WARM FRONT. OBS INDICATE LIKELY WARM FRONT FROM ABOUT WATERTOWN TO CANBY MN THEN TOWARD HUTCHINSON MN THEN TO THE TWIN CITIES. IT HAS BEEN MOVING NORTHWARD. RAP SHOWS LOW LEVEL JET FEEDING INTO BAND OF STORMS THAT HAS BEEN SLOWLY LIFTING NORTHEAST THRU CNTRL MN TURNING A BIT MORE SOUTHWEST TO NORTHEAST ORIENTATION AFTER 00Z AND THUS FOCUS OF PRECIP WILL SHIFT EAST. REGIONAL RADARS SHOWING NOW SOME DEVELOPING SOUTHWEST OF LINE INTO THE WARM SECTOR WEST OF WILMAR..THOUGH IT IS WEAK NOW. IDEA FROM EARLIER SWOMCD IS FOR ACTIVITY TO INCREASE IN THE AREA NORTHWEST AND WEST OF THE TWIN CITIES NEXT FEW HOURS. IT DOES APPEAR MORE AND MORE LIKELY THAT ONLY THE FAR SOUTHEASTERN FCST AREA WILL HAVE ANY IMPACTS FROM THESE STORMS AND THAT MOST WILL STAY JUST SOUTHEAST OF OUR AREA. THUS TRIMMED POPS SOME BUT DID KEEP SEVERE MENTION AT LEAST FOR NOW INTO THE EVE IN FAR SOUTHEASTERN FCST AREA. REST OF THE AREA DRY THRU MID EVENING. THEN WHAT HAPPENS IS IN QUESTION. RAP SHOWS A DEVELOPING LOW LEVEL JET AND QUITE STRONG 850 THETA-E ADVECTION AND AN AREA OF SHOWWALTERS TO -10C MOVING NORTH INTO SE ND 06Z AND JUST AFTERWARDS. MAIN FORCING WILL BE MORE NORTHWEST TOWARD UPPER LOW IN SOUTHEASTERN SASK. MODELS NOT EXCITED ABOUT TOO MUCH IN THIS ELEVATED UNSTABLE LAYER AS IT MOVES INTO SE ND OVERNIGHT BUT AREA IS IN FAVORABLE POSITION OF LOW LEVEL JET (LEFT QUAD) AND STRONG INSTABILITY GRADIENT SO WOULDNT BE SUPRISED IF TSTMS DEVELOP OVERNIGHT AHD OF COLD FRONT IN A MORE WIDESPREAD FASHION THAN MODEL ADVERTISES. ANYHOW....DID KEEP SEVERE MENTION OVERNIGHT PER DAY 1 SLIGHT RISK OVER CNTRL INTO SE ND AND THIS CAN BE ADJUSTED AS NEEDED. IF 850 MB SHOWWALTERS AND LOW LEVEL JET ARE ACCURATE THEN WOULD BE ENOUGH FOR SOME SEVERE HAILERS. MU CAPES INTHE 2500 J/KG RANGE IN SE ND. LESS INSTABILITY FARTHER NORTH BUT MAYBE A BIT BETTER CHC OF A BAND OF SHOWERS/STORMS LATE NIGHT INTO EARLY THURSDAY. PRECIP WILL EXIT NW MN THURSDAY AFTN...THEN DRIER AND COOLER AIR MOVES IN THU NIGHT. THOUGH SOME WRAPAROUND CLOUD COVER PSBL ESP IN NW MN. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 319 PM CDT WED SEP 3 2014 HIGH PRESSURE IN CONTROL FRIDAY WITH LIKELY DIURNAL CU WITH COOLER AIR ALOFT. FOR FRI NIGHT INTO TUESDAY... A NORTHWEST FLOW PATTERN ALOFT...VOID OF ANY APPRECIABLE MOISTURE TRANSPORT INTO THE AREA...WILL KEEP A DRY AND COOL AIR MASS IN PLACE THROUGH THE UPCOMING WEEKEND. THE UPPER AIR PATTERN BECOMES ZONAL SUNDAY AND TURNS TO THE SOUTHWEST SUNDAY NIGHT...WITH LEE SIDE LOW PRESSURE MOVING INTO THE PLAINS ON MONDAY. THIS WILL OPEN UP THE GULF FOR INCREASED MOISTURE TRANSPORT INTO THE AREA AND BRING MORE ACTIVE WEATHER FOR THE EARLY TO MIDDLE PART OF NEXT WEEK. TEMPERATURES WILL TYPICALLY BE RIGHT AT OR SLIGHTLY COOLER THAN SEASONAL NORMS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 113 PM CDT WED SEP 3 2014 VFR CONDS WILL CONTINUE THROUGH THE DAY AND INTO THE LATE EVENING. THUNDERSTORMS ARE THEN EXPECTED TO SPREAD ACROSS THE AREA BY EARLY THU MORNING...WITH CIGS GENERALLY REMAINING VFR EXCEPT IN VCNTY OF TSTMS. WILL KEEP VCTS IN ALL TAF SITES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...RIDDLE LONG TERM... RIDDLE/SPEICHER AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS TULSA OK
604 PM CDT WED SEP 3 2014 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD AT ALL SITES. && .PREV DISCUSSION... /ISSUED 353 PM CDT WED SEP 3 2014/ DISCUSSION... WARM TEMPERATURES AND BREEZY SOUTHERLY WINDS WERE COMMON ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON AS HIGH PRESSURE CONTINUED TO HOLD OVER THE SOUTHERN PLAINS. SOME SCATTERED CONVECTION HAD DEVELOPED OVER FAR SOUTHEAST KANSAS LATE THIS AFTERNOON...AND THE LATEST HRRR TRIES TO DEVELOP THIS PRECIP AND PUSH IT SOUTHEAST INTO NORTHWEST/NORTH CENTRAL OKLAHOMA THIS EVENING AND OVERNIGHT. WILL KEEP POPS BELOW MENTIONABLE CRITERIA FOR NOW AS MOST OF THIS ACTIVITY SHOULD REMAIN NORTHWEST OF THE CWA. EVENING SHIFT WILL NEED TO MONITOR FOR ANY CHANGING CONDITIONS. HOT TEMPERATURES AND BREEZY SOUTH SOUTHWESTERLY WINDS WILL CONTINUE ACROSS THE CWA THURSDAY BEFORE A COLD FRONT IS EXPECTED TO MOVE INTO THE REGION FRIDAY. A WAVE MOVING EASTWARD ALONG THE U.S./CANADA BORDER WILL PUSH A TRAILING COLD FRONT SOUTHEASTWARD THROUGH THE PLAINS AND INTO THE CWA DURING THE DAY FRIDAY. CHANCES FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE FRIDAY MORNING AS THE FRONT NEARS THE REGION AND SHOULD INCREASE IN COVERAGE FRIDAY AFTERNOON/EVENING WHILE THE FRONT PUSHES INTO THE CWA. CONDITIONS AHEAD OF THE FRONT AND PRECIP SHOULD CONTINUE TO BE WARM WITH SOUTHWESTERLY WINDS. THE FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH THE REGION FRIDAY NIGHT AND SATURDAY WITH CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS. POST FRONTAL PRECIP WILL BE POSSIBLE SATURDAY NIGHT INTO SUNDAY BEFORE THE UPPER LEVEL TROF AXIS ASSOCIATED WITH THE WAVE OVER SOUTHERN CANADA MOVES OUT OF THE PLAINS. IN THE WAKE OF THE EXITING TROF...COOLER TEMPS AND NORTHERLY WINDS ARE EXPECTED ACROSS THE REGION INTO THE START OF THE NEXT WORK WEEK. SOUTHERLY WINDS QUICKLY RETURN WITH WARMER TEMPERATURES AGAIN FOR THE MIDDLE PART OF NEXT WEEK AHEAD OF A LONGWAVE TROF FORECAST TO MOVE OUT OF SOUTHERN CANADA INTO THE PLAINS. LATEST GFS AND ECMWF DISAGREE ON TIMING OF THIS NEXT WAVE AND ASSOCIATED COLD FRONT INTO THE CWA. THE ECMWF IS ABOUT 12-24 HRS FASTER COMPARED TO THE GFS. WILL USE A BLENDED MODEL SOLUTION ALONG WITH PREVIOUS FORECAST...PUSHING THE FRONT THROUGH WEDNESDAY NIGHT AND THURSDAY. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL AGAIN BECOME POSSIBLE MID WEEK AND CONTINUE INTO THE SECOND HALF OF NEXT WEEK AS THE FRONT MOVES THROUGH. COOLER TEMPS WILL AGAIN BE POSSIBLE LATE NEXT WEEK. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...23
AREA FORECAST DISCUSSION
NWS TULSA OK
353 PM CDT WED SEP 3 2014 .DISCUSSION... WARM TEMPERATURES AND BREEZY SOUTHERLY WINDS WERE COMMON ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON AS HIGH PRESSURE CONTINUED TO HOLD OVER THE SOUTHERN PLAINS. SOME SCATTERED CONVECTION HAD DEVELOPED OVER FAR SOUTHEAST KANSAS LATE THIS AFTERNOON...AND THE LATEST HRRR TRIES TO DEVELOP THIS PRECIP AND PUSH IT SOUTHEAST INTO NORTHWEST/NORTH CENTRAL OKLAHOMA THIS EVENING AND OVERNIGHT. WILL KEEP POPS BELOW MENTIONABLE CRITERIA FOR NOW AS MOST OF THIS ACTIVITY SHOULD REMAIN NORTHWEST OF THE CWA. EVENING SHIFT WILL NEED TO MONITOR FOR ANY CHANGING CONDITIONS. HOT TEMPERATURES AND BREEZY SOUTH SOUTHWESTERLY WINDS WILL CONTINUE ACROSS THE CWA THURSDAY BEFORE A COLD FRONT IS EXPECTED TO MOVE INTO THE REGION FRIDAY. A WAVE MOVING EASTWARD ALONG THE U.S./CANADA BORDER WILL PUSH A TRAILING COLD FRONT SOUTHEASTWARD THROUGH THE PLAINS AND INTO THE CWA DURING THE DAY FRIDAY. CHANCES FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE FRIDAY MORNING AS THE FRONT NEARS THE REGION AND SHOULD INCREASE IN COVERAGE FRIDAY AFTERNOON/EVENING WHILE THE FRONT PUSHES INTO THE CWA. CONDITIONS AHEAD OF THE FRONT AND PRECIP SHOULD CONTINUE TO BE WARM WITH SOUTHWESTERLY WINDS. THE FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH THE REGION FRIDAY NIGHT AND SATURDAY WITH CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS. POST FRONTAL PRECIP WILL BE POSSIBLE SATURDAY NIGHT INTO SUNDAY BEFORE THE UPPER LEVEL TROF AXIS ASSOCIATED WITH THE WAVE OVER SOUTHERN CANADA MOVES OUT OF THE PLAINS. IN THE WAKE OF THE EXITING TROF...COOLER TEMPS AND NORTHERLY WINDS ARE EXPECTED ACROSS THE REGION INTO THE START OF THE NEXT WORK WEEK. SOUTHERLY WINDS QUICKLY RETURN WITH WARMER TEMPERATURES AGAIN FOR THE MIDDLE PART OF NEXT WEEK AHEAD OF A LONGWAVE TROF FORECAST TO MOVE OUT OF SOUTHERN CANADA INTO THE PLAINS. LATEST GFS AND ECMWF DISAGREE ON TIMING OF THIS NEXT WAVE AND ASSOCIATED COLD FRONT INTO THE CWA. THE ECMWF IS ABOUT 12-24 HRS FASTER COMPARED TO THE GFS. WILL USE A BLENDED MODEL SOLUTION ALONG WITH PREVIOUS FORECAST...PUSHING THE FRONT THROUGH WEDNESDAY NIGHT AND THURSDAY. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL AGAIN BECOME POSSIBLE MID WEEK AND CONTINUE INTO THE SECOND HALF OF NEXT WEEK AS THE FRONT MOVES THROUGH. COOLER TEMPS WILL AGAIN BE POSSIBLE LATE NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... TUL 77 97 75 94 / 0 0 10 30 FSM 74 95 73 95 / 0 10 10 10 MLC 75 95 74 94 / 0 0 0 10 BVO 73 96 69 92 / 0 10 10 40 FYV 69 91 67 92 / 10 10 10 30 BYV 70 93 69 92 / 10 10 10 30 MKO 74 95 73 94 / 0 10 10 30 MIO 73 95 71 91 / 0 10 10 40 F10 75 95 74 94 / 0 0 10 30 HHW 74 95 73 95 / 0 0 0 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...30 LONG TERM....20
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
500 PM CDT WED SEP 3 2014 .MESOSCALE DISCUSSION... ISSUED AT 500 PM CDT WED SEP 3 2014 CONVECTIVE EVOLUTION FOR TONIGHT REMAINS UNCERTAIN...SO PLAN ON PROVIDING MESOSCALE DISCUSSION UPDATES THROUGHOUT THE EVENING. ONGOING SHOWERS AND THUNDERSTORMS FROM NORTH OF ST CLOUD INTO NORTHERN WI EXIST ON THE NOSE OF 925-850MB MOISTURE TRANSPORT...AS WELL AS NORTH OF A WARM FRONTAL BOUNDARY SITUATED ALONG I-94. THESE HAVE CONTINUED TO MOVE NORTHEAST THROUGH THE DAY AS A RESULT OF PERSISTENT SOUTHERLY FLOW...AS SEEN ON KMPX VAD WIND PROFILE. WATER VAPOR FOR THE MOST PART IS VERY NON-DESCRIPT IN TERMS OF EASILY IDENTIFIABLE SHORTWAVES FROM THE DAKOTAS INTO OUR REGION. THERE COULD BE ONE NEAR ABERDEEN SD AND ANOTHER NEAR OMAHA...BOTH MOVING NORTHEAST...BUT THATS IT. CLOSELY MONITORING TO SEE IF CONVECTION CAN DEVELOP OVER WEST- CENTRAL MN OVER THE NEXT FEW HOURS. IF IT DOES AND CAN EVOLVE INTO AN MCS...WHICH WOULD SEEM LIKELY GIVEN STRENGTHENING 850MB MOISTURE TRANSPORT THROUGH THE EVENING AND PLENTIFUL CAPE...CORFIDI VECTORS WOULD BRING IT INTO THE AREA. OTHERWISE...SEEMS THE MAIN FOCUS FOR THE EVENING IS WATCHING THE STRONGER CONVECTION NORTH OF ST CLOUD AND IF IT CAN MATURE INTO AN MCS...CAUSING IT TO ROLL THROUGH LOCATIONS MAINLY ALONG/NORTH OF I-94 LATE IN THE EVENING. HEADING INTO THE OVERNIGHT...THE 03.20Z/21Z RAP...03.19Z/20Z HRRR AND THE 03.18Z NAM-NEST ALL POP UP CONVECTION OVER NORTHEAST IOWA AND SOUTHWEST WI BETWEEN MIDNIGHT AND 2 AM. THIS IS ON THE NOSE OF A SECOND 850MB MOISTURE TRANSPORT MAXIMA COMING UP THROUGH IOWA...LIKELY INDUCED BY THE NORMAL NOCTURNAL INCREASE AND THE TWO SHORTWAVES APPROACHING THE AREA FROM THE WEST. WILL KEEP AN EYE ON THIS SCENARIO THROUGH THE EVENING. SHOULD THIS SCENARIO OCCUR...RAP SOUNDINGS SUGGEST VERY HEAVY RAIN THAT COULD RESULT IN FLASH FLOODING AND MARGINALLY SEVERE HAIL WOULD BE THE MAIN HAZARDS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 350 PM CDT WED SEP 3 2014 AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH- CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR TRAINING CELLS. FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES. ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE FORECAST TOWARD IT. ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION CHANCES IN THE 20 TO 50 PERCENT RANGE. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 350 PM CDT WED SEP 3 2014 ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY... THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF LARGE HAIL. ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR. FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY SEVERE WEATHER AT THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1245 PM CDT WED SEP 3 2014 GUSTY SOUTH WINDS ARE EXPECTED AT THE TAF SITES TODAY AS A WARM FRONT LIFTS THROUGH THE REGION...WITH SOUTH WINDS OF 13 TO 16 KTS WITH GUSTS AROUND 25 KTS POSSIBLE. LOOK FOR SCT TO BKN CUMULUS THIS AFTERNOON WITH CLOUD BASES IN THE 2-4KFT RANGE. SHOWERS AND STORMS ARE EXPECTED TO DEVELOP NORTH OF THE TAF SITES LATE THIS AFTERNOON AND EARLY EVENING...CLOSER TO THE INTERSTATE 94 CORRIDOR NEAR THE TWIN CITIES. THESE STORMS ARE THEN EXPECTED TO TRACK EAST/SOUTHEAST INTO PORTION OF WESTERN AND NORTHERN WISCONSIN. AT THIS TIME THE STORMS LOOK TO STAY NORTH OF THE TAF SITES BUT IF THEY TAKE A HARD SOUTHEAST TURN...THEY COULD IMPACT KLSE AND POSSIBLY KRST. IF THEY WOULD MAKE IT TO THE TAF SITES...STRONG AND GUSTY WINDS WOULD BE A POSSIBILITY. WILL HAVE TO KEEP A VERY CLOSE EYE ON THE EVOLUTION OF THE STORMS LATE THIS AFTERNOON INTO THIS EVENING. ANOTHER CONCERN TONIGHT WILL BE LOW LEVEL WIND SHEAR WITH A STRONG LOW LEVEL JET SETTING UP THIS EVENING AND PERSISTING INTO THE OVERNIGHT HOURS. PLAN ON WINDS INCREASING TO 50 KTS AT 2KFT. THE LOW LEVEL JET WILL SUBSIDE AFTER 14Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ MESOSCALE...AJ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
352 PM CDT WED SEP 3 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 350 PM CDT WED SEP 3 2014 AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH- CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR TRAINING CELLS. FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES. ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE FORECAST TOWARD IT. ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION CHANCES IN THE 20 TO 50 PERCENT RANGE. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 350 PM CDT WED SEP 3 2014 ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY... THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF LARGE HAIL. ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR. FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY SEVERE WEATHER AT THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1245 PM CDT WED SEP 3 2014 GUSTY SOUTH WINDS ARE EXPECTED AT THE TAF SITES TODAY AS A WARM FRONT LIFTS THROUGH THE REGION...WITH SOUTH WINDS OF 13 TO 16 KTS WITH GUSTS AROUND 25 KTS POSSIBLE. LOOK FOR SCT TO BKN CUMULUS THIS AFTERNOON WITH CLOUD BASES IN THE 2-4KFT RANGE. SHOWERS AND STORMS ARE EXPECTED TO DEVELOP NORTH OF THE TAF SITES LATE THIS AFTERNOON AND EARLY EVENING...CLOSER TO THE INTERSTATE 94 CORRIDOR NEAR THE TWIN CITIES. THESE STORMS ARE THEN EXPECTED TO TRACK EAST/SOUTHEAST INTO PORTION OF WESTERN AND NORTHERN WISCONSIN. AT THIS TIME THE STORMS LOOK TO STAY NORTH OF THE TAF SITES BUT IF THEY TAKE A HARD SOUTHEAST TURN...THEY COULD IMPACT KLSE AND POSSIBLY KRST. IF THEY WOULD MAKE IT TO THE TAF SITES...STRONG AND GUSTY WINDS WOULD BE A POSSIBILITY. WILL HAVE TO KEEP A VERY CLOSE EYE ON THE EVOLUTION OF THE STORMS LATE THIS AFTERNOON INTO THIS EVENING. ANOTHER CONCERN TONIGHT WILL BE LOW LEVEL WIND SHEAR WITH A STRONG LOW LEVEL JET SETTING UP THIS EVENING AND PERSISTING INTO THE OVERNIGHT HOURS. PLAN ON WINDS INCREASING TO 50 KTS AT 2KFT. THE LOW LEVEL JET WILL SUBSIDE AFTER 14Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1108 AM CDT WED SEP 3 2014 .UPDATE...FOR SEVERE WEATHER POTENTIAL TONIGHT ISSUED AT 1108 AM CDT WED SEP 3 2014 THE SEVERE WEATHER THREAT REMAINS ON TRACK FOR TONIGHT. SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON INTO EARLY THIS EVENING OVER PORTIONS OF CENTRAL MINNESOTA THEN TRACK EAST INTO WISCONSIN THROUGH THE EVENING HOURS. CONFIDENCE IS THE HIGHEST ON AREAS ALONG AND NORTH OF INTERSTATE 94 SEEING THIS ACTIVITY. DAMAGING WINDS...LARGE HAIL...AND HEAVY RAINFALL APPEAR THE BE THE MAIN HAZARDS. CANNOT RULE OUT AN ISOLATED TORNADO IF THE STORMS WOULD MOVE IN DURING THE EARLY TO MID EVENING HOURS. MESOSCALE MODELS CONTINUE TO SHOW THE BULK OF THE ACTIVITY IMPACTING LOCATIONS NORTH OF INTERSTATE 94...IMPACTING MAINLY CLARK AND TAYLOR COUNTIES. HOWEVER...THE 12Z NAM AND 00Z ECMWF CONTINUE TO BRING AN MCS SOUTHEAST INTO THE FORECAST AREA FROM THE TWIN CITIES AREA AROUND MID EVENING. IF THIS TRACK HOLDS...LOCATIONS NORTH OF INTERSTATE 90 WOULD BE IMPACTED. WILL HAVE TO KEEP AN EYE ON HEAVY RAIN POTENTIAL TONIGHT AS WELL WITH PRECIPITABLE WATER VALUES INCREASING INTO THE 1.8 TO 2.0 INCH RANGE AND WARM CLOUD DEPTHS CLIMBING TO 4.0 KM. MOISTURE CONTINUES TO STREAM NORTHWARD THROUGH IOWA LATE THIS MORNING WITH DEW POINTS CLIMBING INTO 70S. SO MOISTURE IS STREAMING NORTHWARD AND WILL FUEL SEVERE THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON INTO THIS EVENING. ONGOING STORMS THIS MORNING OVER CENTRAL MINNESOTA SHOULD DISSIPATE AND CONTINUE TO SHIFT NORTH INTO EARLY THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 338 AM CDT WED SEP 3 2014 MAIN CONCERN FOCUSED ON SEVERE POTENTIAL TONIGHT AND AGAIN THURSDAY NIGHT. WATER VAPOR OR BIG PICTURE VIEW SHOWS A FAIRLY HIGH ZONAL FLOW ACROSS THE NORTHERN CONUS. A WEAK EMBEDDED MID-LEVEL TROUGH WAS NOTED EJECTING NORTHEAST OUT OF WY INTO WESTERN SD. AT THE SURFACE...A WARM FRONT EXTENDED FROM SOUTHWEST SD INTO EASTERN NEB. LIFT AHEAD OF THE WAVE AND WARM FRONT WAS PRODUCING A SMALL AREA OF SHOWERS/THUNDERSTORMS OVER EASTERN SD/FAR SOUTHWEST MN PER LATEST REGIONAL RADAR MOSAIC. OTHERWISE...CLOSER TO HOME...HIGH PRESSURE WAS PRODUCING MOSTLY CLEAR SKIES ACROSS THE FORECAST AREA WITH TEMPERATURES RANGING FROM THE LOWER 50S A NEAR 60 DEGREES. FOR TODAY...SURFACE CYCLOGENESIS WILL CONTINUE TO TAKE SHAPE OVER MT/NORTHERN PLAINS. THIS WILL LIFT THE AFOREMENTIONED WARM FRONT OUT OF THE CENTRAL PLAINS INTO SOUTHERN MN. ALSO...STRENGTHENING SOUTHERLY FLOW WILL PRODUCE INCREASING MOISTURE TRANSPORT/ISENTROPIC LIFT INTO THE AREA. THIS IS EXPECTED TO FUEL ELEVATED AND SCATTERED SHOWERS/THUNDERSTORMS MAINLY ALONG AND NORTH OF I-90 THROUGH THE DAY. PLAN ON HIGHS IN THE 75-85 DEGREE RANGE. AS WE GO INTO TONIGHT...STRENGTHENING LOW PRESSURE MOVING FROM THE DAKOTAS INTO WESTERN MN WILL DRIVE THE WARM FRONT FARTHER NORTHEAST...NEAR THE I-94 CORRIDOR BY MORNING. THIS IS WHERE IT GETS COMPLICATED. 850MB MOISTURE TRANSPORTS CRANKS UP SIGNIFICANTLY WITH VECTORS POINTED DIRECTLY INTO THE AREA. AT THE SAME TIME...STRONG CAP SETS UP ALONG THE MISSISSIPPI RIVER AS EVIDENCED BY THE NAM/GFS BUFKIT SOUNDINGS. EXPECTING A COMPLEX OF THUNDERSTORMS TO FIRE SOMEWHERE ALONG I-94 BETWEEN THE TWIN CITIES AND SAINT CLOUD MN BY THIS EVENING ON THE EDGE OF THIS CAP AND ON THE NOSE OF THE MOISTURE TRANSPORT. FORWARD PROPAGATING CORFIDI VECTORS BRING THIS COMPLEX SOUTHEAST AND THEN ON A MORE SOUTHERLY TRAJECTORY ONCE IT GETS EAST OF THE MISSISSIPPI...AGAIN ON THE EDGE OF THE CAP AND IN THE CORRIDOR OF VERY RICH MOISTURE FEED. THIS COMPLEX WILL HAVE TO BE WATCHED CLOSELY FOR SEVERE THREAT. EARLY ON IN THE EVENING...MODEL CONSENSUS 0-3KM MUCAPE OF 2500- 4000J/KG AND 0-6KM BULK SHEAR OF 40-50KT WILL BE SUFFICIENT FOR SUPERCELL DEVELOPMENT MAINLY ACROSS EAST CENTRAL MN INTO NORTHWEST WI FOR LARGE HAIL POTENTIAL...AND TORNADO THREAT IF STORMS GET ROOTED IN THE BOUNDARY LAYER. AS MENTIONED...THEN EXPECTING THIS THUNDERSTORM COMPLEX TO FOLLOW CORFIDI VECTORS...TAKING INTO DIRECTLY OVER OUR AREA MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. BY THEN MOST OF THESE STORMS WILL BE ELEVATED IN NATURE. WITH PRECIPITABLE WATER VALUES OF 1.5-2 INCHES OFF THE NAM AND GFS...HEAVY RAINFALL BECOMES THE MAIN THREAT ALONG WITH DAMAGING WIND POTENTIAL. SOME LARGE HAIL WILL ALSO BE POSSIBLE. CANNOT RULE OUT THE POSSIBILITY OF SOME FLASH FLOODING IF THERE IS ANY REPETITIVE CONVECTION OVER NAY ONE AREA...BUT SYSTEM SEEMS OVERALL PRETTY PROGRESSIVE IN NATURE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 338 AM CDT WED SEP 3 2014 MODELS SHOW DEEP AREA OF LOW PRESSURE MOVING NORTH OUT OF WESTERN MN INTO WESTERN ONTARIO BY LATE AFTERNOON. AS A RESULT...WARM FRONT WILL PUSH NORTHEAST THROUGH THE AREA WITH A VERY WARM/HUMID/CAPPED DAY IN STORE. HIGH TEMPERATURES ARE EXPECTED TO PUSH INTO THE 85-91 DEGREE RANGE WITH DEW POINTS IN THE LOWER 70S. THIS WILL RESULT IN HEAT INDICES OF 90-100. AS THE LOW CONTINUES TO LIFT NORTHEAST INTO ONTARIO A COLD FRONT WILL THEN PUSH THROUGH THE AREA THURSDAY NIGHT. INITIALLY THE AREA REMAINS UNDER THE INFLUENCE OF THE STRONG CAP...BUT CONVECTION IS EXPECTED TO EVENTUALLY FIRE IN THE EVENING AFTER 6 PM...AS THE FRONT/ALONG WITH MID-LEVEL TROUGH MOVES IN WITH COOLING ALOFT...WHICH SHOULD THEN BE ENOUGH TO OVERCOME THE CAP. SOME OF THESE STORMS SHOULD BE COME SEVERE WITH DAMAGING WIND AND LARGE HAIL BEING THE MAIN THREATS. FOR FRIDAY INTO THE WEEKEND... DRIER/COOLER AIR MOVES INTO THE AREA FRIDAY BEHIND THE FRONT. LOOK FOR HIGHS IN THE UPPER 60S TO THE MIDDLE 70S. COOL AND DRY CONDITIONS LOOK TO PERSIST THROUGH THE WEEKEND AS CANADIAN HIGH PRESSURE DOMINATES THE MID-SECTION OF THE CONUS/UPPER MISSISSIPPI RIVER VALLEY REGIONS. HIGHS SATURDAY AND SUNDAY STAY IN THE UPPER 60S/LOWER 70S WITH OVERNIGHT LOWS DIPPING INTO THE 40S AND LOWER 50S. FOR MONDAY INTO TUESDAY... HIGH PRESSURE DRIFTS OFF TO THE EAST AS LOW PRESSURE APPROACHES FROM THE PLAINS. AS A RESULT...PLAN ON SHOWER/THUNDERSTORM CHANCES TO INCREASE THROUGH THE PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 617 AM CDT WED SEP 3 2014 AREA OF ELEVATED SHOWERS AND STORMS OVER SOUTHWEST MINNESOTA IN ASSOCIATION WITH A WEAK SHORT WAVE TROUGH. THE 03.09Z RAP SUGGESTS THE WAVE WILL CONTINUE TO MOVE EAST TOWARD THE AREA WHILE THE MID LEVEL MOISTURE TRANSPORT LIFTS NORTHEAST. THE 03.00Z HI-RES ARW AND 03.09Z HRRR BOTH SUGGEST THE ACTIVITY WILL LIFT NORTHEAST WITH THE MOISTURE TRANSPORT AND MISS BOTH TAF SITES. FEEL THE BULK OF THE ACTIVITY SHOULD MISS THE TAF SITES BUT WILL CARRY A VCTS AT KRST IN THE EVENT THAT THE MOVEMENT ENDS UP BEING MORE TO THE EAST. AFTER THAT...WARM AIR ALOFT WILL RAPIDLY BUILD OVER THE AREA TODAY PUTTING A CAP IN PLACE THAT SHOULD ALLOW THE NEXT ROUND OF CONVECTION TO FORM NORTH OF BOTH TAF SITES LATE THIS AFTERNOON INTO THE EVENING. ALL THE MESO MODELS SUGGEST THE ACTIVITY WILL THEN STAY NORTH OF THE AREA THROUGH THE OVERNIGHT...BUT THE 03.00Z ECMWF SUGGEST SOME SOUTHEAST MOVEMENT ALONG THE EDGE OF THE CAP CLOSE TO THE BACKWARD PROPAGATING CORFIDI VECTORS. IF THIS CAN OCCUR...THERE IS A CHANCE SOME ACTIVITY COULD MOVE DOWN THE MISSISSIPPI RIVER INTO WESTERN WISCONSIN AND WILL CONTINUE TO CARRY A VCTS IN THE LATE EVENING FOR THIS AT KLSE BUT THINK IT WILL MISS KRST...IF IT CAN TURN SOUTHEAST. WITH THE STRONG LOW LEVEL JET FEEDING INTO THE CONVECTIVE ACTIVITY...LOW LEVEL WIND SHEAR SHOULD BE PRESENT AND HAVE INCLUDED THIS OUTSIDE OF THE THUNDER TIME IN THE EVENING AND OVERNIGHT HOURS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...WETENKAMP SHORT TERM...DAS LONG TERM...DAS AVIATION...04