Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/25/12


AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1000 PM MDT SUN JUL 22 2012 .UPDATE... ISSUED AT 1000 PM MDT SUN JUL 22 2012 SIGNIFICANT CONVECTION HAS SUBSIDED FOR THE EVENING. THE ONLY LARGE AREA OF SHOWERS AND A FEW DISSIPATING THUNDERSTORMS WILL CONTINUE MOVING NORTHEAST OVER THE CO NW PLATEAU UNTIL SHORTLY AFTER MIDNIGHT. AFTER THAT ONLY ISOLATED SHOWERS ARE EXPECTED OVERNIGHT...MAINLY OVER THE MOUNTAINS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 248 PM MDT SUN JUL 22 2012 RIDGE OVER THE GREAT PLAINS AND TROUGH OVER THE WEST COAST CONTINUE TO ALLOW A MOIST SOUTHERLY FETCH OVER THE FORECAST AREA THROUGH THE SHORT TERM PERIOD. A BIT MORE CLOUD COVER THIS MORNING HAS DELAYED ONSET OF CONVECTION BUT AS CONDITIONS ARE STARTING TO CLEAR OUT EARLY THIS AFTERNOON ACTIVITY HAS PULSED UP IN THE LAST HOUR. RUC13 AND WV ARE SHOWING TWO POTENTIAL TRIGGERS IN THIS FLOW THIS AFTERNOON. ONE IS OVER CENTRAL ARIZONA WHICH IS EXPECTED TO MOVE EAST ACROSS THE FOUR CORNERS REGION BY LATE THIS AFTERNOON. THE OTHER IS OVER SOUTHWESTERN COLORADO EARLY THIS AFTERNOON AND IS EXPECTED TO MOVE SLOWLY NORTHEAST THIS AFTERNOON. THE MAIN THREAT ONCE AGAIN WILL BE HEAVY RAIN WITH SOME ISOLATED FLASH FLOODING POSSIBLE...ALONG WITH FREQUENT CLOUD TO RAIN LIGHTNING. SHOWER AND THUNDERSTORM ACTIVITY WILL DECREASE AFTER MIDNIGHT. BY MONDAY...PACIFIC NORTHWEST TROUGH WILL MOVE SLOWLY EAST...OTHERWISE NOT MUCH CHANGE IN WEATHER PATTERN WITH ABUNDANT MOISTURE IN PLACE...EXPECT ANOTHER ROUND OF SCATTERED TO NUMEROUS AFTERNOON AND EVENING THUNDERSTORMS WITH THE POTENTIAL FOR HEAVY RAIN. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 248 PM MDT SUN JUL 22 2012 UPPER CLOSED LOW OVER SRN ALBERTA WILL DRIFT SLOWLY EWRD TUESDAY... FLATTENING THE RIDGE OF HIGH PRESSURE THAT HAS BEEN OVER OUR REGION. THIS WILL ALSO USHER IN A WIND SHIFT TO THE NORTHWEST. SOME DYNAMIC INSTABILITY WILL HELP TO GENERATE ANOTHER AFTERNOON OF WIDESPREAD CONVECTION TUESDAY AFTERNOON. HOWEVER SIGNIFICANT DRYING ALOFT IS SEEN FROM THE NORTHWEST TUESDAY NIGHT AND WEDNESDAY. THIS WILL RESULT IN A NOTABLE DOWNTURN IN CONVECTION WEDNESDAY OVER MOST OF THE CWA...EXCEPT NEAR AND ALONG THE CONTINENTAL DIVIDE WHERE A LITTLE DEEPER MOISTURE WILL RESIDE. SHEAR PROFILE ALSO LOOKS LIKE IT MAY BECOME A LITTLE MORE FAVORABLE FOR STRONGER STORM DEVELOPMENT IN THAT AREA. HIGH PRESSURE WILL START TO REBUILD OVER THE SRN GRT BASIN THURSDAY HELPING HELPING TO SUPPRESS CONVECTION...BUT LOW LEVEL MOISTURE SHOULD STILL BE IN PLACE FOR AT LEAST ISOLATED STORM DEVELOPMENT. THE NEXT UPSTREAM TROF IN THE GULF OF ALASKA WILL APPROACH OUR PACIFIC COAST FRIDAY WHICH WILL PUSH THE ABOVE MENTIONED HIGH PRESSURE CELL EASTWARD...WHICH WILL THEN ALLOW A SOUTHWESTERLY FLOW TO REDEVELOP. ACCOMPANYING THIS FLOW WILL BE ANOTHER SURGE OF SUB-TROPICAL MOISTURE. THIS WILL BRING INCREASING CHANCES OF SHOWER AND THUNDERSTORM DEVELOPMENT FRIDAY AFTERNOON THROUGH THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1000 PM MDT SUN JUL 22 2012 VFR CONDITIONS WILL PREVAIL AT ALL TAFS SITES OVERNIGHT AND MONDAY MORNING. UNTIL ABOUT 09Z LOCAL MVFR CONDITIONS WILL BE FOUND OVER THE MOUNTAINS AND HIGH PASSES OF NW COLORADO AND ALONG THE CONTINENTAL DIVIDE NORTH OF I-70. ON MONDAY...EXPECT SIMILAR SHOWER AND THUNDERSTORM DEVELOPMENT BEGINNING IN EARLY AFTERNOON AND PEAKING BETWEEN ABOUT 00Z AND 03Z...WITH AREAS OF MVFR CIGS AND VSBYS IN HEAVIER SHOWERS. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...CC SHORT TERM...MPM LONG TERM...MC AVIATION...CC
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
543 AM EDT MON JUL 23 2012 .SYNOPSIS... A WEAK COLD FRONT WILL APPROACH THE REGION EARLY TODAY AND GRADUALLY DISSIPATE. MEANWHILE, A STRONGER COLD FRONT WILL ADVANCE THROUGH THE GREAT LAKES REGION TONIGHT AND TRACK INTO OUR AREA TUESDAY. THIS FRONT EVENTUALLY STALLS TO OUR SOUTH WEDNESDAY AS HIGH PRESSURE BRIEFLY INFLUENCES OUR AREA. FROM THURSDAY INTO FRIDAY, A WARM FRONT WILL APPROACH AND LIFT NORTHWARD THROUGH THE REGION, FOLLOWED BY A COLD FRONT FROM THE WEST TRACKING ACROSS THE MID ATLANTIC AROUND SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE FORECAST PROBLEM FOR TODAY IS CONVECTION EARLY ON...AND AGAIN THIS AFTERNOON. THE MAIN CONVECTIVE BATCH EARLY THIS MORNING IS FORMING IN THE SOUTHERN TIER OF NEW YORK STATE...MOVING INTO THE LOWER HUDSON VALLEY. IT APPEARS TO BE FOLLOWING THE CIN/NO CIN LINE...AND DRIVEN MAINLY BY SHORT WAVES IN THE WEST NORTHWEST MID LEVEL FLOW. THE MAIN BATCH APPEARS AS THOUGH IT WILL FOLLOW THE BEST LOW TO MID LEVEL THETA E...AND PASS NORTH OF THE FORECAST AREA. THERE IS MORE CONVECTIVE BEHIND THE MAIN BATCH...ACROSS WESTERN AND CENTRAL NEW YORK START. THIS ACTIVITY ALSO SEEMS TO BE FOLLOWING THE SAME LINE. THE LATEST HRRR SHOWS THE ACTIVITY STAYING NORTH OF THE AREA. HOWEVER...IT MAY BE POSSIBLE THAT ELEVATED CONVECTION COULD FORM ON THE DEEPER OUTFLOW...AND A SLIGHT CHANCE WILL BE MAINTAINED ACROSS NORTHERN ZONES THROUGH DAYBREAK. A WEAKENING COLD FRONT OVER THE GREAT LAKES MAY GET INTO LEHIGH VALLEY THIS AFTERNOON BEFORE FINALLY DISSIPATING AFTER OUTRUNNING ITS SUPPORT. THE FRONT COULD END UP BEING THE FOCUS FOR CONVECTION LATE THIS MORNING INTO THIS AFTERNOON. INSTABILITY SHOULD BE PRESENT IN JUST ABOUT ALL AREAS...SO A MID LEVEL TRIGGER WILL BE NEEDED TO GET THE PROCESS ROLLING. THERE APPEAR TO BE A FEW SUCH IMPULSES IN THE MID LEVEL WEST TO NORTHWEST FLOW...SO TIMING COULD END UP BEING AN ISSUE. THE 0000 NAM IS A COUPLE OF HOURS FASTER THAN THE GFS WITH CONVECTIVE STARTUP...AND THIS COULD BE A FUNCTION OF THE CONVECTIVE SCHEME BEING USED. LATE MORNING COULD BE A TAD EARLY...AS CONVECTIVE TEMPERATURES WILL NOT YET HAVE BEEN MET. FOR THIS FORECAST...THE BULK OF THE CONVECTION WILL BE PUSHED BACK INTO THE AFTERNOON... ESPECIALLY ACROSS SOUTHERN AREAS. MODIFIED MODEL SOUNDINGS SHOW BETTER MEAN LAYER CAPE VALUES ACROSS SOUTHERN AREAS...AND THERE SHOULD BE MORE IN THE WAY OF SUNSHINE THERE AS WELL (AS LONG AS THE LOW CLOUDS PRESENT NOW EXIT ON TIME). THE MODIFIED SOUNDINGS ALSO SHOW ENOUGH DRY AIR IN THE MID LEVELS... AS WELL AS DCAPE...TO SUGGEST GUSTY WINDS WITH THE THUNDER. TOYING WITH THE IDEA OF INCLUDING GUSTY WINDS WITH THE THUNDERSTORMS ACROSS SOUTHERN AREAS THIS AFTERNOON...BASED ON THE ABOVE WITH SOME WET MICROBURST POTENTIAL. FURTHER NORTH...INCREASED SHEAR MAY INCREASE THE ORGANIZATION OF THE CONVECTION...WITH WIND AGAIN BEING THE MAIN CONVECTIVE MODE. GUSTY WINDS WILL BE INCLUDED HERE DUE TO THE ORGANIZATION POTENTIAL. WHILE HAIL COULD BE A THREAT WITH MARGINAL MID LEVEL LAPSE RATES...THIS WILL NOT BE INCLUDED FOR NOW. MORE DEBRIS CLOUDINESS SHOULD NOT INTERFERE TOO MUCH WITH HEATING THIS MORNING. THE HEATING SHOULD ALLOW ALL AREAS TO REACH CONVECTIVE TEMPERATURES...SO CUMULUS WILL FILL IN LATER THIS MORNING AND THIS AFTERNOON. 850 MB TEMPERATURES NEAR 17 CELSIUS WOULD SUGGEST FULL SUN HIGHS NEAR 90. WE MAY END UP COMING JUST SHORT OF THIS...AND HIGHS TODAY WERE CLOSER TO THE MOS BLEND. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... CONVECTION WILL BE THE FORECAST PROBLEM FOR THIS PERIOD ONCE AGAIN. THE EVENING CONVECTION SHOULD DIE OFF SOUTH...BUT ACROSS THE NORTH THE CONVECTION MAY STILL HAVE SOME ORGANIZATION DUE TO INCREASING SHEAR. A CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE INCLUDED FOR BOTH OF THE ABOVE. THE NEXT CONVECTIVE QUESTION COMES LATE TONIGHT AND EARLY TUESDAY MORNING. MODELS ARE STILL POINTING TO THE POTENTIAL FOR ORGANIZED CONVECTION (IN THE FORM OF AN MCS?) POSSIBLY AFFECTING NORTHWEST AREAS. INSTABILITY SHOULD BE ELEVATED ACROSS THE ABOVEMENTIONED AREA BY 0900 UTC TUESDAY...AND THIS IS SHOWN BY MODEL SOUNDINGS. WHILE 45 KNOTS OF WIND COULD BE AVAILABLE AT 850 MB WITH THE POSSIBLE MCS... MOIST (AND STABILIZING) LOW LEVELS COULD MITIGATE THE THREAT OF GUSTY WINDS. SINCE IT IS UNCLEAR JUST HOW MUCH OF AN IMPACT THIS CONVECTIVE POTENTIAL COULD HAVE...NO ENHANCED WORDING WILL BE INTRODUCED INTO THE FORECAST NOW. PERHAPS THE GREATER THREAT MAY BE HEAVY RAIN...AS PRECIPITABLE WATER VALUES PEAK NEAR 1.85 INCHES. STORM MOTION SHOULD BE SUFFICIENT TO LEAVE THE FLASH FLOOD THREAT LOW...AND GUIDANCE NUMBERS ARE STILL FAIRLY HIGH. LOWS WERE BASED MAINLY ON A BLEND OF MOS NUMBERS AND THE PREVIOUS FORECAST. && .LONG TERM /TUESDAY THROUGH SUNDAY/... TO START THE LONG TERM, A COLD FRONT WILL BE APPROACHING THE REGION FROM AROUND THE GREAT LAKES. THERE COULD BE SOME SCATTERED ONGOING SHWR/T-STORM ACTIVITY AROUND DAYBREAK TUESDAY AS SOME MODELS STILL SHOW A POSSIBLE REMNANT MCS MAKING IT INTO THE AREA OVERNIGHT MONDAY INTO THE EARLY MORNING OF TUESDAY. FROM THERE, THE COLD FRONT PROGRESSES INTO THE REGION DURING TUESDAY, BUT THERE CONTINUE TO BE ENOUGH MODEL DIFFERENCES WITH THE FRONTAL PASSAGE THAT CONFIDENCE IN THE COVERAGE AND STRENGTH OF THE CONVECTION IS BELOW AVERAGE. BOTH THE GFS AND ECMWF SHOW A VORT MAX DIVING SOUTH IN THE NORTHWEST FLOW ALOFT, PASSING OVER THE DELMARVA REGION AND SOUTHERN NJ. THIS IS ALSO THE REGION WHERE MU CAPES ARE PROGGED TO BE THE HIGHEST. HOWEVER, DURING THE COURSE OF THE DAY THE MODELS SHOW NEGATIVE THETA E ADVECTION. FOR NOW, WE HAVE DECIDED TO MAINTAIN THE SLIGHT CHANCE TO CHANCE POPS FOR CONVECTION, WITH THE HIGHER POPS NEAR AND OVER THE DELMARVA REGION. THERE IS STILL THE POTENTIAL FOR SOME STORMS TO PRODUCE GUSTY WINDS AND HEAVY RAIN GIVEN THE ENVIRONMENTAL CONDITIONS, BUT WITH BELOW AVERAGE CONFIDENCE IN STORM COVERAGE, WE HAVE NOT YET INCLUDED THESE ELEMENTS IN THE GRIDS AND WILL CONTINUE TO MAKE A MENTION IN THE HWO. IN ADDITION TO THE PROGGED CONVECTIVE ACTIVITY, TUESDAY WILL BE A VERY WARM AND FAIRLY HUMID DAY. WARM WESTERLY WINDS AHEAD OF THE SURFACE COLD FRONT WILL PUSH MAX TEMPERATURES INTO THE LOWER 90S FOR MOST AREAS. HOWEVER THIS COULD DEPEND ON HOW MUCH LEFTOVER CLOUD COVER REMAINS FROM ANY EARLY MORNING CONVECTIVE ACTIVITY. DEWPOINTS ARE PROGGED TO BE FALLING DURING THE DAY, AND THUS WE EXPECT TO FALL BELOW CRITERIA FOR ANY HEAT RELATED HEADLINES. HOWEVER, WE WILL STILL MAKE A MENTION OF THIS CONCERN IN THE HWO. BEHIND THIS COLD FRONTAL PASSAGE, HIGH PRESSURE IS PROGGED TO BRIEFLY RETURN OVER THE REGION FOR WEDNESDAY. AMPLE SUN IS EXPECTED FOR THE FCST AREA ALONG WITH A COOLER, DRIER AIRMASS IN PLACE. DEWPOINTS ARE FORECAST TO BE IN THE 50S. THIS WILL NOT LAST FOR LONG, HOWEVER, AS A WARM FRONT IS FCST TO APPROACH AND ADVANCE THROUGH THE REGION THURSDAY INTO FRIDAY. FOR THE MOST PART, CHANCE POPS HAVE BEEN MAINTAINED FOR SCATTERED SHWR/T-STORM ACTIVITY IN THIS TIMEFRAME. UNSETTLED WEATHER WILL CONTINUE THEN FOR THE FCST AREA INTO SATURDAY AS A COLD FRONT APPROACHES FROM THE WEST AND PASSES THROUGH THE REGION. CHANCE POPS WERE ALSO RETAINED FOR CONVECTIVE ACTIVITY. FOLLOWING THE FRONTAL PASSAGE, THE MODELS SHOW AN AREA OF HIGH PRESSURE BUILDING INTO THE REGION, AND A PRECIP FREE FCST IS MAINTAINED ON SUNDAY. FOR TEMPERATURES, A BLEND OF HPC GUIDANCE AND CONTINUITY WAS USED FOR MUCH OF THE LONG TERM. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. CONDITIONS ARE VFR EARLY THIS MORNING. A BAND OF STRATOCUMULUS AROUND 5000 FEET CONTINUES TO FORM AND BREAK OFF. A PATCHY OF MVFR CEILINGS WILL MOVE ACROSS EASTERN PENNSYLVANIA AND WESTERN NEW JERSEY THROUGH 1000 UTC. THE MVFR CEILINGS ARE NOT EXPECTED TO LAST MORE THAN 60 TO 90 MINUTES AT ANY LOCATION. A BATCH OF THUNDERSTORMS OVER THE SOUTHERN TIER OF NEW YORK STATE SHOULD REMAIN NORTH OF THE AREA THIS MORNING. THE TERMINAL SITE WITH THE BEST CHANCE OF BEING AFFECTED IS KABE...BUT IT WILL NOT BE INCLUDED IN THE NEW FORECAST. SHOULD IT BE THREATENED...THE TERMINAL FORECAST WAS BE UPDATED TO INCLUDE THE THREAT. OTHERWISE...PATCHY MVFR FOG IS POSSIBLE AT KRDG...KMIV AND KILG...BUT HIGH CLOUDINESS SUGGESTS THAT THIS IS NOT A LOCK. NAM MODEL SOUNDINGS SHOW LIFR CEILINGS AROUND DAYBREAK...BUT THIS APPEARS TO BE OVERDONE IN THE LIGHT SOUTHWEST FLOW...AND WAS NOT INCLUDED IN THE 0600 UTC FORECAST. A MAINLY VFR TODAY IS EXPECTED...BUT CONVECTION WILL START THIS MORNING...AND COULD BECOME A PROBLEM THIS AFTERNOON. THE START TIME OF THE CONVECTION IS NOT SET IN STONE YET...AND COULD BEGIN AS EARLY AS 1500 UTC FOR KRDG AND KABE. ELSEWHERE...THE WINDOW OF OPPORTUNITY FOR CONVECTION TO AFFECT THE KPHL METRO AIRPORTS APPEARS TO BE 1900 UTC TO 2300 UTC...BUT THIS TIMING WILL BE REFINED DURING THE MORNING HOURS. WINDS SHOULD BE SOUTHWEST...GENERALLY LESS THAN 12 KNOTS. THE CONVECTION SHOULD DIE OFF THIS EVENING...WITH MAINLY VFR CONDITIONS EXPECTED. PATCHY MVFR FOG IS POSSIBLE IN THE USUAL LOCATIONS (KRDG...KMIV). A BATCH OF THUNDERSTORMS COULD AFFECT THE REGION AFTER 0900 UTC TUESDAY...BUT CONFIDENCE IN THIS TIMING IS LOW AT THIS TIME. OUTLOOK... TUESDAY...MAINLY VFR CONDITIONS EXPECTED. SCATTERED SHWR/T-STORM ACTIVITY MAY CREATE LOCAL MVFR CONDITIONS FOR A TIME, ESPECIALLY FOR SOUTHERN LOCATIONS. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...VFR CONDITIONS. THURSDAY...VFR CONDITIONS FOR MUCH OF THE DAY. SCATTERED SHWRS/T-STORMS MAY PRODUCE SOME MVFR IN THE LATTER PART OF THE DAY. THURSDAY NIGHT THROUGH FRIDAY...SHWR/T-STORM ACTIVITY ASSOCIATED WITH A WARM FRONT IS EXPECTED TO YIELD MVFR OR EVEN IFR FOR A TIME. && .MARINE... WINDS OVER THE HIGHER PLATFORMS OF THE DELAWARE BAY REMAIN BETWEEN 10 AND 15 KNOTS...BUT ELSEWHERE WINDS ARE GENERALLY LESS THAN 15 KNOTS. WIND SPEEDS PROBABLY DROP OFF A BIT BEFORE DAYBREAK...AS SEAS REMAIN 3 FEET OR LESS. SEA AND BAY BREEZES MAY BE ABLE TO DEVELOP LATER THIS MORNING OR EARLY THIS AFTERNOON...BEFORE THE GRADIENT FLOW STARTS TO INCREASE. THE SUPERIMPOSITION OF THE SEA AND BAY BREEZE CIRCULATIONS COULD RESULT IN SOUTH TO SOUTHWEST WIND GUSTS NEAR 20 KNOTS ACROSS SOUTHERN OCEAN WATERS AND THE DELAWARE BAY LATE THIS AFTERNOON. HOWEVER...WIND GUSTS ARE NOT EXPECTED TO EXCEED 25 KNOTS...SO NO MARINE HEADLINES ARE ANTICIPATED. WINDS SHOULD BACK OFF LATE THIS EVENING...THOUGH THIS MAY BE A SLOWER PROCESS ON THE DELAWARE BAY THAN OVER THE OCEAN WATERS. THE SOUTH TO SOUTHWEST FETCH COULD BRING SEAS OVER THE NORTHERN OCEAN WATERS CLOSER TO 4 FEET...BUT THIS COULD JUST BE THE NORMAL WAVEWATCH OVERESTIMATION OF SEAS ON THE SOUTH SOUTHWEST FLOW. NO HEADLINES ARE EXPECTED. OUTLOOK... IN THE EXTENDED PERIOD, THE BEST OPPORTUNITY OF REACHING SCA CRITERIA LOOKS TO BE THURSDAY NIGHT INTO EARLY FRIDAY WITH A WARM FRONT PASSING THROUGH THE REGION. WIND GUSTS AND SEAS ARE FORECAST TO JUST MEET CRITERIA AT THIS TIME. OTHERWISE, WINDS AND SEAS ARE EXPECTED TO BE SUB-SCA DURING THE EXTENDED. && .RIP CURRENTS... OUR SPOTTER ON LONG BEACH ISLAND IS REPORTING A MODERATE SOUTH TO NORTH CURRENT. THIS COMBINED WITH THE SOUTHEAST SWELL WILL RESULT IN A MODERATE RISK OF RIP CURRENTS...ESPECIALLY AROUND THE TIME OF TIDE CHANGE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLINE NEAR TERM...HAYES SHORT TERM...HAYES LONG TERM...KLINE AVIATION...HAYES/KLINE MARINE...HAYES/KLINE RIP CURRENTS...HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
414 AM EDT MON JUL 23 2012 .SYNOPSIS... A WEAK COLD FRONT WILL APPROACH THE REGION EARLY TODAY AND GRADUALLY DISSIPATE. MEANWHILE, A STRONGER COLD FRONT WILL ADVANCE THROUGH THE GREAT LAKES REGION TONIGHT AND TRACK INTO OUR AREA TUESDAY. THIS FRONT EVENTUALLY STALLS TO OUR SOUTH WEDNESDAY AS HIGH PRESSURE BRIEFLY INFLUENCES OUR AREA. FROM THURSDAY INTO FRIDAY, A WARM FRONT WILL APPROACH AND LIFT NORTHWARD THROUGH THE REGION, FOLLOWED BY A COLD FRONT FROM THE WEST TRACKING ACROSS THE MID ATLANTIC AROUND SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE FORECAST PROBLEM FOR TODAY IS CONVECTION EARLY ON...AND AGAIN THIS AFTERNOON. THE MAIN CONVECTIVE BATCH EARLY THIS MORNING IS FORMING IN THE SOUTHERN TIER OF NEW YORK STATE...MOVING INTO THE LOWER HUDSON VALLEY. IT APPEARS TO BE FOLLOWING THE CIN/NO CIN LINE...AND DRIVEN MAINLY BY SHORT WAVES IN THE WEST NORTHWEST MID LEVEL FLOW. THE MAIN BATCH APPEARS AS THOUGH IT WILL FOLLOW THE BEST LOW TO MID LEVEL THETA E...AND PASS NORTH OF THE FORECAST AREA. THERE IS MORE CONVECTIVE BEHIND THE MAIN BATCH...ACROSS WESTERN AND CENTRAL NEW YORK START. THIS ACTIVITY ALSO SEEMS TO BE FOLLOWING THE SAME LINE. THE LATEST HRRR SHOWS THE ACTIVITY STAYING NORTH OF THE AREA. HOWEVER...IT MAY BE POSSIBLE THAT ELEVATED CONVECTION COULD FORM ON THE DEEPER OUTFLOW...AND A SLIGHT CHANCE WILL BE MAINTAINED ACROSS NORTHERN ZONES THROUGH DAYBREAK. A WEAKENING COLD FRONT OVER THE GREAT LAKES MAY GET INTO LEHIGH VALLEY THIS AFTERNOON BEFORE FINALLY DISSIPATING AFTER OUTRUNNING ITS SUPPORT. THE FRONT COULD END UP BEING THE FOCUS FOR CONVECTION LATE THIS MORNING INTO THIS AFTERNOON. INSTABILITY SHOULD BE PRESENT IN JUST ABOUT ALL AREAS...SO A MID LEVEL TRIGGER WILL BE NEEDED TO GET THE PROCESS ROLLING. THERE APPEAR TO BE A FEW SUCH IMPULSES IN THE MID LEVEL WEST TO NORTHWEST FLOW...SO TIMING COULD END UP BEING AN ISSUE. THE 0000 NAM IS A COUPLE OF HOURS FASTER THAN THE GFS WITH CONVECTIVE STARTUP...AND THIS COULD BE A FUNCTION OF THE CONVECTIVE SCHEME BEING USED. LATE MORNING COULD BE A TAD EARLY...AS CONVECTIVE TEMPERATURES WILL NOT YET HAVE BEEN MET. FOR THIS FORECAST...THE BULK OF THE CONVECTION WILL BE PUSHED BACK INTO THE AFTERNOON... ESPECIALLY ACROSS SOUTHERN AREAS. MODIFIED MODEL SOUNDINGS SHOW BETTER MEAN LAYER CAPE VALUES ACROSS SOUTHERN AREAS...AND THERE SHOULD BE MORE IN THE WAY OF SUNSHINE THERE AS WELL (AS LONG AS THE LOW CLOUDS PRESENT NOW EXIT ON TIME). THE MODIFIED SOUNDINGS ALSO SHOW ENOUGH DRY AIR IN THE MID LEVELS... AS WELL AS DCAPE...TO SUGGEST GUSTY WINDS WITH THE THUNDER. TOYING WITH THE IDEA OF INCLUDING GUSTY WINDS WITH THE THUNDERSTORMS ACROSS SOUTHERN AREAS THIS AFTERNOON...BASED ON THE ABOVE WITH SOME WET MICROBURST POTENTIAL. FURTHER NORTH...INCREASED SHEAR MAY INCREASE THE ORGANIZATION OF THE CONVECTION...WITH WIND AGAIN BEING THE MAIN CONVECTIVE MODE. GUSTY WINDS WILL BE INCLUDED HERE DUE TO THE ORGANIZATION POTENTIAL. WHILE HAIL COULD BE A THREAT WITH MARGINAL MID LEVEL LAPSE RATES...THIS WILL NOT BE INCLUDED FOR NOW. MORE DEBRIS CLOUDINESS SHOULD NOT INTERFERE TOO MUCH WITH HEATING THIS MORNING. THE HEATING SHOULD ALLOW ALL AREAS TO REACH CONVECTIVE TEMPERATURES...SO CUMULUS WILL FILL IN LATER THIS MORNING AND THIS AFTERNOON. 850 MB TEMPERATURES NEAR 17 CELSIUS WOULD SUGGEST FULL SUN HIGHS NEAR 90. WE MAY END UP COMING JUST SHORT OF THIS...AND HIGHS TODAY WERE CLOSER TO THE MOS BLEND. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... CONVECTION WILL BE THE FORECAST PROBLEM FOR THIS PERIOD ONCE AGAIN. THE EVENING CONVECTION SHOULD DIE OFF SOUTH...BUT ACROSS THE NORTH THE CONVECTION MAY STILL HAVE SOME ORGANIZATION DUE TO INCREASING SHEAR. A CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE INCLUDED FOR BOTH OF THE ABOVE. THE NEXT CONVECTIVE QUESTION COMES LATE TONIGHT AND EARLY TUESDAY MORNING. MODELS ARE STILL POINTING TO THE POTENTIAL FOR ORGANIZED CONVECTION (IN THE FORM OF AN MCS?) POSSIBLY AFFECTING NORTHWEST AREAS. INSTABILITY SHOULD BE ELEVATED ACROSS THE ABOVEMENTIONED AREA BY 0900 UTC TUESDAY...AND THIS IS SHOWN BY MODEL SOUNDINGS. WHILE 45 KNOTS OF WIND COULD BE AVAILABLE AT 850 MB WITH THE POSSIBLE MCS... MOIST (AND STABILIZING) LOW LEVELS COULD MITIGATE THE THREAT OF GUSTY WINDS. SINCE IT IS UNCLEAR JUST HOW MUCH OF AN IMPACT THIS CONVECTIVE POTENTIAL COULD HAVE...NO ENHANCED WORDING WILL BE INTRODUCED INTO THE FORECAST NOW. PERHAPS THE GREATER THREAT MAY BE HEAVY RAIN...AS PRECIPITABLE WATER VALUES PEAK NEAR 1.85 INCHES. STORM MOTION SHOULD BE SUFFICIENT TO LEAVE THE FLASH FLOOD THREAT LOW...AND GUIDANCE NUMBERS ARE STILL FAIRLY HIGH. LOWS WERE BASED MAINLY ON A BLEND OF MOS NUMBERS AND THE PREVIOUS FORECAST. && .LONG TERM /TUESDAY THROUGH SUNDAY/... TO START THE LONG TERM, A COLD FRONT WILL BE APPROACHING THE REGION FROM AROUND THE GREAT LAKES. THERE COULD BE SOME SCATTERED ONGOING SHWR/T-STORM ACTIVITY AROUND DAYBREAK TUESDAY AS SOME MODELS STILL SHOW A POSSIBLE REMNANT MCS MAKING IT INTO THE AREA OVERNIGHT MONDAY INTO THE EARLY MORNING OF TUESDAY. FROM THERE, THE COLD FRONT PROGRESSES INTO THE REGION DURING TUESDAY, BUT THERE CONTINUE TO BE ENOUGH MODEL DIFFERENCES WITH THE FRONTAL PASSAGE THAT CONFIDENCE IN THE COVERAGE AND STRENGTH OF THE CONVECTION IS BELOW AVERAGE. BOTH THE GFS AND ECMWF SHOW A VORT MAX DIVING SOUTH IN THE NORTHWEST FLOW ALOFT, PASSING OVER THE DELMARVA REGION AND SOUTHERN NJ. THIS IS ALSO THE REGION WHERE MU CAPES ARE PROGGED TO BE THE HIGHEST. HOWEVER, DURING THE COURSE OF THE DAY THE MODELS SHOW NEGATIVE THETA E ADVECTION. FOR NOW, WE HAVE DECIDED TO MAINTAIN THE SLIGHT CHANCE TO CHANCE POPS FOR CONVECTION, WITH THE HIGHER POPS NEAR AND OVER THE DELMARVA REGION. THERE IS STILL THE POTENTIAL FOR SOME STORMS TO PRODUCE GUSTY WINDS AND HEAVY RAIN GIVEN THE ENVIRONMENTAL CONDITIONS, BUT WITH BELOW AVERAGE CONFIDENCE IN STORM COVERAGE, WE HAVE NOT YET INCLUDED THESE ELEMENTS IN THE GRIDS AND WILL CONTINUE TO MAKE A MENTION IN THE HWO. IN ADDITION TO THE PROGGED CONVECTIVE ACTIVITY, TUESDAY WILL BE A VERY WARM AND FAIRLY HUMID DAY. WARM WESTERLY WINDS AHEAD OF THE SURFACE COLD FRONT WILL PUSH MAX TEMPERATURES INTO THE LOWER 90S FOR MOST AREAS. HOWEVER THIS COULD DEPEND ON HOW MUCH LEFTOVER CLOUD COVER REMAINS FROM ANY EARLY MORNING CONVECTIVE ACTIVITY. DEWPOINTS ARE PROGGED TO BE FALLING DURING THE DAY, AND THUS WE EXPECT TO FALL BELOW CRITERIA FOR ANY HEAT RELATED HEADLINES. HOWEVER, WE WILL STILL MAKE A MENTION OF THIS CONCERN IN THE HWO. BEHIND THIS COLD FRONTAL PASSAGE, HIGH PRESSURE IS PROGGED TO BRIEFLY RETURN OVER THE REGION FOR WEDNESDAY. AMPLE SUN IS EXPECTED FOR THE FCST AREA ALONG WITH A COOLER, DRIER AIRMASS IN PLACE. DEWPOINTS ARE FORECAST TO BE IN THE 50S. THIS WILL NOT LAST FOR LONG, HOWEVER, AS A WARM FRONT IS FCST TO APPROACH AND ADVANCE THROUGH THE REGION THURSDAY INTO FRIDAY. FOR THE MOST PART, CHANCE POPS HAVE BEEN MAINTAINED FOR SCATTERED SHWR/T-STORM ACTIVITY IN THIS TIMEFRAME. UNSETTLED WEATHER WILL CONTINUE THEN FOR THE FCST AREA INTO SATURDAY AS A COLD FRONT APPROACHES FROM THE WEST AND PASSES THROUGH THE REGION. CHANCE POPS WERE ALSO RETAINED FOR CONVECTIVE ACTIVITY. FOLLOWING THE FRONTAL PASSAGE, THE MODELS SHOW AN AREA OF HIGH PRESSURE BUILDING INTO THE REGION, AND A PRECIP FREE FCST IS MAINTAINED ON SUNDAY. FOR TEMPERATURES, A BLEND OF HPC GUIDANCE AND CONTINUITY WAS USED FOR MUCH OF THE LONG TERM. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. CONDITIONS ARE VFR EARLY THIS MORNING. A BAND OF STRATOCUMULUS AROUND 5000 FEET CONTINUES TO FORM AND BREAK OFF. A PATCHY OF MVFR CEILINGS WILL MOVE ACROSS EASTERN PENNSYLVANIA AND WESTERN NEW JERSEY THROUGH 1000 UTC. THE MVFR CEILINGS ARE NOT EXPECTED TO LAST MORE THAN 60 TO 90 MINUTES AT ANY LOCATION. A BATCH OF THUNDERSTORMS OVER THE SOUTHERN TIER OF NEW YORK STATE SHOULD REMAIN NORTH OF THE AREA THIS MORNING. THE TERMINAL SITE WITH THE BEST CHANCE OF BEING AFFECTED IS KABE...BUT IT WILL NOT BE INCLUDED IN THE NEW FORECAST. SHOULD IT BE THREATENED...THE TERMINAL FORECAST WAS BE UPDATED TO INCLUDE THE THREAT. OTHERWISE...PATCHY MVFR FOG IS POSSIBLE AT KRDG...KMIV AND KILG...BUT HIGH CLOUDINESS SUGGESTS THAT THIS IS NOT A LOCK. NAM MODEL SOUNDINGS SHOW LIFR CEILINGS AROUND DAYBREAK...BUT THIS APPEARS TO BE OVERDONE IN THE LIGHT SOUTHWEST FLOW...AND WAS NOT INCLUDED IN THE 0600 UTC FORECAST. A MAINLY VFR TODAY IS EXPECTED...BUT CONVECTION WILL START THIS MORNING...AND COULD BECOME A PROBLEM THIS AFTERNOON. THE START TIME OF THE CONVECTION IS NOT SET IN STONE YET...AND COULD BEGIN AS EARLY AS 1500 UTC FOR KRDG AND KABE. ELSEWHERE...THE WINDOW OF OPPORTUNITY FOR CONVECTION TO AFFECT THE KPHL METRO AIRPORTS APPEARS TO BE 1900 UTC TO 2300 UTC...BUT THIS TIMING WILL BE REFINED DURING THE MORNING HOURS. WINDS SHOULD BE SOUTHWEST...GENERALLY LESS THAN 12 KNOTS. THE CONVECTION SHOULD DIE OFF THIS EVENING...WITH MAINLY VFR CONDITIONS EXPECTED. PATCHY MVFR FOG IS POSSIBLE IN THE USUAL LOCATIONS (KRDG...KMIV). A BATCH OF THUNDERSTORMS COULD AFFECT THE REGION AFTER 0900 UTC TUESDAY...BUT CONFIDENCE IN THIS TIMING IS LOW AT THIS TIME. OUTLOOK... TUESDAY...MAINLY VFR CONDITIONS EXPECTED. SCATTERED SHWR/T-STORM ACTIVITY MAY CREATE LOCAL MVFR CONDITIONS FOR A TIME, ESPECIALLY FOR SOUTHERN LOCATIONS. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...VFR CONDITIONS. THURSDAY...VFR CONDITIONS FOR MUCH OF THE DAY. SCATTERED SHWRS/T-STORMS MAY PRODUCE SOME MVFR IN THE LATTER PART OF THE DAY. THURSDAY NIGHT THROUGH FRIDAY...SHWR/T-STORM ACTIVITY ASSOCIATED WITH A WARM FRONT IS EXPECTED TO YIELD MVFR OR EVEN IFR FOR A TIME. && .MARINE... WINDS OVER THE HIGHER PLATFORMS OF THE DELAWARE BAY REMAIN BETWEEN 10 AND 15 KNOTS...BUT ELSEWHERE WINDS ARE GENERALLY LESS THAN 15 KNOTS. WIND SPEEDS PROBABLY DROP OFF A BIT BEFORE DAYBREAK...AS SEAS REMAIN 3 FEET OR LESS. SEA AND BAY BREEZES MAY BE ABLE TO DEVELOP LATER THIS MORNING OR EARLY THIS AFTERNOON...BEFORE THE GRADIENT FLOW STARTS TO INCREASE. THE SUPERIMPOSITION OF THE SEA AND BAY BREEZE CIRCULATIONS COULD RESULT IN SOUTH TO SOUTHWEST WIND GUSTS NEAR 20 KNOTS ACROSS SOUTHERN OCEAN WATERS AND THE DELAWARE BAY LATE THIS AFTERNOON. HOWEVER...WIND GUSTS ARE NOT EXPECTED TO EXCEED 25 KNOTS...SO NO MARINE HEADLINES ARE ANTICIPATED. WINDS SHOULD BACK OFF LATE THIS EVENING...THOUGH THIS MAY BE A SLOWER PROCESS ON THE DELAWARE BAY THAN OVER THE OCEAN WATERS. THE SOUTH TO SOUTHWEST FETCH COULD BRING SEAS OVER THE NORTHERN OCEAN WATERS CLOSER TO 4 FEET...BUT THIS COULD JUST BE THE NORMAL WAVEWATCH OVERESTIMATION OF SEAS ON THE SOUTH SOUTHWEST FLOW. NO HEADLINES ARE EXPECTED. OUTLOOK... IN THE EXTENDED PERIOD, THE BEST OPPORTUNITY OF REACHING SCA CRITERIA LOOKS TO BE THURSDAY NIGHT INTO EARLY FRIDAY WITH A WARM FRONT PASSING THROUGH THE REGION. WIND GUSTS AND SEAS ARE FORECAST TO JUST MEET CRITERIA AT THIS TIME. OTHERWISE, WINDS AND SEAS ARE EXPECTED TO BE SUB-SCA DURING THE EXTENDED. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLINE NEAR TERM...HAYES SHORT TERM...HAYES LONG TERM...KLINE AVIATION...HAYES/KLINE MARINE...HAYES/KLINE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
113 AM EDT MON JUL 23 2012 .SYNOPSIS... A HIGH PRESSURE SYSTEM OFF OF THE NEW JERSEY COAST WILL MOVE FARTHER OFFSHORE EARLY THIS MORNING. A WEAK COLD FRONT WILL APPROACH THE REGION TODAY AND DISSIPATE. A STRONGER FRONT WILL CROSS THE REGION ON TUESDAY AND STALL NEAR VIRGINIA AS A HIGH PRESSURE SYSTEM BRIEFLY BUILDS INTO THE AREA. A WARM FRONT WILL APPROACH THE REGION THURSDAY AND THURSDAY NIGHT AND MOVE NORTH OF THE AREA ON FRIDAY. A COLD FRONT FROM THE GREAT LAKES SHOULD PASS ACROSS THE AREA AROUND SATURDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE SOUTHERN EDGE OF THE CONVECTIVE ELEMENT TRAIL FORMING IN THE LOWER HUDSON VALLEY HAS EXTENDED INTO NEW JERSEY...REACHING TOWARD THE MONMOUTH COUNTY COAST. THE SOUTHERN EDGE OF THE CONVECTIVE ELEMENTS IS ALMOST CERTAINLY ELEVATED...AS THE 0000 UTC OKX SOUNDING (AND THE EXPANDING CLUTTER ON THE KDIX RADAR) SHOWS STABLE LOW LEVELS. THE FORECAST HAS BEEN UPDATED TO ACCOUNT FOR THIS ACTIVITY...WHICH PROBABLY DOES NOT LAST MUCH LONGER. THE NEXT QUESTION FOR THE OVERNIGHT IS WHAT (IF ANY) OF THE ACTIVITY OVER WESTERN AND WEST CENTRAL NEW YORK STATE WILL AFFECT NORTHERN AREAS LATE TONIGHT. THE BEST LOW TO MID LEVELS THETA AXIS LOWS TO STAY NORTH OF THE AREA...SO THE BEST ACTIVITY SHOULD FOLLOW THAT TRAIL. THE WATER VAPOR DOES SHOW ONE OR TWO WEAK IMPULSES IN THE WEST NORTHWEST MID LEVEL FLOW. EITHER ONE OF THESE ELEMENTS...ALONG WITH THE INSTABILITY WESTERN NEW YORK STATE (SHOWN ON THE 0000 UTC KBUF SOUNDING) COULD BRING SOME OF THE SHOWERS AND THUNDERSTORMS TO NORTHWEST ZONES...MAINLY BETWEEN 0900 UTC AND 1200 UTC MONDAY. THIS IDEA IS SUPPORTED BY THE LATEST HRRR FORECAST...AS WELL AS THE 0000 UTC NAM. IT IS POSSIBLE THAT THE DEVELOPING ACTIVITY OUTRUNS ITS INSTABILITY...BUT EVEN ELEVATED ACTIVITY COULD MAKE THE NORTHWEST ZONES. THE FORECAST HAS BEEN UPDATED TO INCLUDE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN POCONOS AND NORTHWEST NEW JERSEY TOWARD DAYBREAK. NO SIGNIFICANT CHANGES WERE MADE TO THE TEMPERATURES...WINDS OR SKY COVER FOR THE REMAINDER OF THE OVERNIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THIS EVENING/... THIS TIME OF YEAR IT TAKES VERY LITTLE ENERGY TO INITIATE CONVECTION ANYWHERE IN OUR CWA AND MONDAY LOOKS TO BE ONE OF THOSE DAYS..AT LEAST EARLY IN THE AFTERNOON. MODELS CONTINUE TO INDICATE A SERIES OF EMBEDDED MID-LEVEL SHORTWAVE TROUGHS OF LOW PRESSURE PUSHING THROUGH TOMORROW, ALTHOUGH THE TIMING IS TRICKY WITH EACH PASSAGE. NONE-THE-LESS, DEWPOINTS WILL BE CLIMBING TO NEAR 70F AND DAYTIME TEMPERATURES CLOSE TO 90 IN MOST SPOTS SO WE HAVE A GOOD SHOT AT SEEING CONVECTION BEGIN BY LATE MORNING. THE SURFACE CONVERGENCE IS NOT ALL THAT GREAT AND THE LOW AND MID-LEVEL LAPSE RATES ARE DECENT, AROUND 6.5C/KM FOR BOTH, THERE IS PLENTY OF MEAN LAYER CAPE TO EAT UP. MID-LEVEL HEIGHT FALLS, WITH THE HELP OF OROGRAPHIC LIFTING, SHOULD BE SUFFICIENT TO GET THINGS GOING ACROSS OUR NORTHWESTERN ZONES BY NOON AND COULD PERMEATE DOWN THROUGH PHILADELPHIA BY MID-AFTERNOON. THE SHEAR PARAMETERS DO INCREASE THROUGHOUT THE DAY SO A FEW ORGANIZED CLUSTERS COULD FORM TO OUR NORTHWEST. PWATS JUMP UPWARDS TO 1.75 TO 2 INCHES BY THE AFTERNOON/EVENING TIMEFRAME SO ANY STORMS WILL DUMP A LOT OF RAIN IN A SHORT TIME PERIOD. DO NOT THINK WE WILL HAVE MANY ISSUES WITH FLASH FLOODING TOMORROW, GIVEN THE STRENGTH OF THE FLOW ALOFT, BUT AS IS ALWAYS THE CASE, POOR DRAINAGE AND LOW-LYING AREAS COULD HAVE ISSUES. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... A FAIRLY ACTIVE LONG TERM IS EXPECTED WITH OSCILLATIONS BETWEEN HOTTER AND MORE HUMID WEATHER, PROBABLY WITH STRONG STORMS AT TRANSITION TIMES, AND A COUPLE OF SEASONABLY PLEASANT DAYS. THE WRF-NMMB`S INITIALIZATION ALOFT WAS SLIGHTLY BETTER THAN THE GFS, BUT THE GFS REMAINED COMPARABLE AT 850MB AND SLIGHTLY BETTER THAN THE WRF-NMMB AT 925MB. OF LATE THE MESOSCALE MODELS HAVE BEEN LESS THAN AVERAGE WITH THE CONVECTIVE SYSTEMS AND AS SUCH OUR CONFIDENCE AS TO THE DETAILS AND TIMING WILL ALSO BE LESS THAN AVERAGE. STARTING ON MONDAY NIGHT CONVECTION OR CHANCES THEREOF SHOULD BE CONTINUING IN OUR CWA AS THE MODELS ARE FORECASTING BOTH DECENT WAA THRU THE NIGHT AND DPVA EARLY. SPEAKING OF THE MESOSCALE MODELS, SOME DO SHOW CHANCES OF AN MCS OR REMNANT LATE. THIS IS SHOWING UP IN THE WRF-NMMB AND ECMWF STABILITY FIELDS AS A FCST TT(S) BULLSEYE PASSES OVERNIGHT. UNTIL WE CAN DECIPHER THIS FURTHER, WE DID CARRY THE HIGHEST POPS EARLY, DROPPED THEM IN THE MIDDLE OF THE NIGHT AND THEN SHOW ANOTHER RISE TOWARD MORNING. SHOULD BE A FAIRLY MUGGY NIGHT BETWEEN THE CLOUDS AND PCPN. STAT GUIDANCE OVERALL LOOKS REASONABLE AND A COMPROMISE/CONTINUITY BLEND WAS FOLLOWED. CAN NOT GET MORE MIXED SIGNALS THAN WE HAVE RIGHT NOW FOR TUESDAY DAY. ON THE ONE HAND WE HAVE THE DYNAMITE NORTHWEST FLOW, NEAR EXIT REGION OF THE H2.5 JET, FCST CAPES ABOVE 2000J, INCREASING FCST BULK SHEAR VALUES OF GREATER THAN 30KTS, MAYBE AN UNTURNED ELEVATED MIXED LAYER AND A 20C DROP OF THETA E WITH HEIGHT FCST. BUT, AT THE SAME TIME THE MODELS DONT EXACTLY HAVE US ON THE CORRECT SIDE OF THAT H2.5 JET, ARE SHOWING WESTERLY FLOW AS FAR DOWNWARD AS 925MB, NEGATIVE LOW LEVEL THETA E ADVECTION DURING THE DAY, DECREASING VS POOLING FCST AFTN DEW POINTS AND THE UNKNOWN AS TO HOW MANY CLOUDS WILL BE AROUND FROM ANY LEFTOVER CONVECTION. THE FCST 925MB WINDS AND NEGATIVE THETA E ADVECTION ARE ENOUGH NEGATIVE SIGNALS FOR NOW TO HOLD POPS IN THE CHANCE CATEGORY. BASED ON THE THERMODYNAMICS, BEST CHANCES WOULD BE SOUTH BECAUSE OF THE FCST INSTABILITY. KINEMATICALLY, GFS REMAINS PRETTY NOISY WITH ITS SHORT WAVES, SO WANT TO SEE HOW THEY DEVELOP (OR DONT) DURING THE NEXT 24 HOURS. FOR NOW SUFFICIENT CHANCE TO MAKE MENTION IN THE HWO ABOUT STRONGER STORMS, BUT TOO LOW CONFIDENCE FOR ANYWHERE ELSE. THERMALLY SPEAKING, ITS HARD TO FIND WHERE THE +26C ON THE WRF-NMMB COMES FROM EARLY ON TUESDAY. REGARDLESS, THERE ARE A NUMBER OF WAYS LOWER 90S ARE STILL POSSIBLE, EITHER WITH THE FRONT BEING SLOWER OR JUST IN THE GENERAL KATABATIC NW SFC FLOW. ONLY WAY WE MAY BE TOO ROBUST WITH MAX TEMPS IS IF CLOUD COVERAGE PERSISTS LONGER THAN WE ARE ANTICIPATING. MAX TEMPS WERE KEPT PRETTY CLOSE TO CONTINUITY. BECAUSE OF THE FCST AFTERNOON NW FLOW IN THE I95 CORRIDOR, AFTN HEAT INDICES ARE EXPECTED TO FALL SHORT OF HEAT RELATED HEADLINES FOR URBAN AREAS AND FALL ABOUT 5F SHORT ELSEWHERE FARTHER TO THE SE. WE MAINTAINED A LOW CHANCE EARLY SOUTH FOR TUESDAY NIGHT, BUT THEN CARRIED NO POPS THE REST OF THE NIGHT. THE NEXT SHORT WAVE IN THE DIGGING TROF IS FORECAST TO REMAIN NE OF OUR CWA. A SUNNY DAY IS IN STORE ON WEDNESDAY WITH A CONSIDERABLY DRIER AIR MASS IN PLACE. MAX TEMPS BASED ON FCST 1000-850MB THICKNESSES WHICH CORROBORATE BOTH MEX AND EC MOS. THEN A RADIATING TYPE NIGHT POTENTIALLY ON WEDNESDAY NIGHT PENDING HOW QUICKLY WAA INDUCED CLOUDS ARRIVE. THE DRIER WEATHER WILL BE SHORT LIVED AS THE NEXT WARM FRONT IS FORECAST TO MOVE OUR WAY ON THURSDAY. POPS WERE KEPT IN FOR THE AFTERNOON. MAX TEMPS WERE SIMILAR TO WEDNESDAY BASED ON MORE CLOUDINESS AND PCPN BEING AROUND TO POSSIBLY SLOW THE RISE. BEYOND THURSDAY, IT BECOMES A BIT MORE MUDDLED AS TO HOW FAR NORTH THE WARM FRONT WILL GET AND CONVERSELY HOW QUICKLY THE NEXT COLD FRONT WILL MOVE THROUGH. THE REST OF THE LONG TERM LEANED TOWARD CONTINUITY UNTIL MORE SOUNDING RUN TO SOUNDING RUN CONSISTENCY OCCURS. THERE SHOULD BE AT LEAST ONE (FRIDAY) AND MAYBE TWO MORE HOT AND HUMID DAYS TOWARD THE END OF THE WEEK, BEFORE MORE RELIEF ARRIVES DURING NEXT WEEKEND. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. CONDITIONS ARE VFR EARLY THIS MORNING. A BAND OF STRATOCUMULUS AROUND 5000 FEET CONTINUES TO FORM AND BREAK OFF ACROSS SOUTHERN AREAS...AFFECTING MAINLY KILG...KMIV AND KACY. THESE CEILINGS ARE EXPECTED TO REMAIN VFR. A BATCH OF THUNDERSTORMS OVER THE SOUTHERN TIER OF NEW YORK STATE SHOULD REMAIN NORTH OF THE AREA THIS MORNING. THE TERMINAL SITE WITH THE BEST CHANCE OF BEING AFFECTED IS KABE...BUT IT WILL NOT BE INCLUDED IN THE NEW FORECAST. SHOULD IT BE THREATENED...THE TERMINAL FORECAST WAS BE UPDATED TO INCLUDE THE THREAT. OTHERWISE...PATCHY MVFR FOG IS POSSIBLE AT KRDG...KMIV AND KILG...BUT HIGH CLOUDINESS SUGGESTS THAT THIS IS NOT A LOCK. NAM MODEL SOUNDINGS SHOW LIFR CEILINGS AROUND DAYBREAK...BUT THIS APPEARS TO BE OVERDONE IN THE LIGHT SOUTHWEST FLOW...AND WAS NOT INCLUDED IN THE 0600 UTC FORECAST. A MAINLY VFR TODAY IS EXPECTED...BUT CONVECTION WILL START THIS MORNING...AND COULD BECOME A PROBLEM THIS AFTERNOON. THE START TIME OF THE CONVECTION IS NOT SET IN STONE YET...AND COULD BEGIN AS EARLY AS 1500 UTC FOR KRDG AND KABE. ELSEWHERE...THE WINDOW OF OPPORTUNITY FOR CONVECTION TO AFFECT THE KPHL METRO AIRPORTS APPEARS TO BE 1900 UTC TO 2300 UTC...BUT THIS TIMING WILL BE REFINED DURING THE MORNING HOURS. WINDS SHOULD BE SOUTHWEST...GENERALLY LESS THAN 12 KNOTS. THE CONVECTION SHOULD DIE OFF THIS EVENING...WITH MAINLY VFR CONDITIONS EXPECTED. PATCHY MVFR FOG IS POSSIBLE IN THE USUAL LOCATIONS (KRDG...KMIV). A BATCH OF THUNDERSTORMS COULD AFFECT THE REGION AFTER 0900 UTC TUESDAY...BUT CONFIDENCE IN THIS TIMING IS LOW AT THIS TIME. OUTLOOK... TUESDAY...MAINLY VFR. SCATTERED THUNDERSTORMS COULD RESULT IN LOCAL MVFR CONDITIONS...MAINLY ACROSS SOUTHERN AREAS. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...VFR CONDITIONS ARE EXPECTED. CONFIDENCE IS HIGH. THURSDAY...MAINLY VFR CONDITIONS ARE EXPECTED. CHANCE OF MVFR CONDITIONS IN SCATTERED SHOWERS AND THUNDERSTORMS IN THE AFTERNOON. THURSDAY NIGHT AND FRIDAY...A PERIOD OF MVFR TO IFR CONDITIONS EXPECTED IN SHOWERS AND THUNDERSTORMS AS THE WARM FRONT MOVES NORTH. GREATEST CONFIDENCE ABOUT THE LATTER NORTH. && .MARINE... MONDAY WILL PERMIT SUB-ADVISORY CONDITIONS AS HIGH PRESSURE MOVES FURTHER TO THE EAST, EVENTUALLY OFFSHORE BY LATE MORNING, WITH WINDS MORE FROM SOUTHWEST LATER IN THE DAY. SEAS WILL BE AROUND 3 FEET TONIGHT AND TOMORROW AND SINCE THE SURFACE FLOW WILL HAVE MORE OF AN OFFSHORE COMPONENT, THEY WILL NOT CLIMB MUCH DURING THE DAY. A WEAK SURFACE BOUNDARY WILL PUSH THROUGH BY LATE IN THE DAY AND COULD TOUCH OFF NUMEROUS SHOWERS AND THUNDERSTORMS OVER OUR WATERS STARTING BY THE MID-AFTERNOON. OUTLOOK... WHILE WINDS ARE FORECAST TO INCREASE ALOFT ON MONDAY NIGHT AND TUESDAY DAY, THE EXPECTATION IS WITH WARMER AIR MOVING IN AT THE SURFACE, EFFICIENT MIXING WILL NOT OCCUR. WINDS AND SEAS WERE KEPT BELOW SMALL CRAFT ADVISORY CRITERIA. GUSTS MAY COME CLOSE. A MORE CONFIDENT CHANCE OF SMALL CRAFT ADVISORY CONDITIONS, ESPECIALLY NORTH AND ON THE OCEAN FOR TUESDAY NIGHT IN THE COOL AIR ADVECTION BEHIND THE DEPARTING FRONT. THIS SHOULD BE SHORT LIVED AND GONE BY WEDNESDAY DAY. THE NEXT CHANCE FOR SMALL CRAFT ADVISORY CONDITIONS MIGHT OCCUR IN THE SOUTHERLY FLOW BETWEEN THE DEPARTING SFC HIGH AND THE APPROACHING WARM FRONT ON THURSDAY AND THURSDAY NIGHT. THIS IS ALWAYS TRICKY AS STATED ABOVE AS MIXING SHOULD NOT BE THAT EFFICIENT. THEN THE GRADIENT IS EXPECTED TO RELAX AFTER THE WARM FRONT MOVES NORTH AS WE AWAIT THE APPROACHING COLD FRONT. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...GIGI/HAYES NEAR TERM...HAYES SHORT TERM...HEAVENER LONG TERM...GIGI AVIATION...GIGI/HAYES MARINE...GIGI/HEAVENER
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
540 PM EDT Mon Jul 23 2012 .MESOSCALE UPDATE... Updated rain chances across our northwestern counties, including SE Alabama and the Florida panhandle. Dry air draped across south Georgia and SE Alabama has suppressed convective development. Only shallow convection as formed in these areas and are very limited temporally. Additionally, the threat for strong storms appears unlikely now, with deep convection kept in check. There still exists the chance for isolated showers through the evening. The bulk of the activity has been across the southeast Big Bend of Florida where moisture is more bountiful. The east coast seabreeze front can also be seen approaching the area. PoPs will remain highest across our eastern forecast area, around 60%. && .NEAR TERM [Through Tonight]... A tropical wave positioned in the extreme eastern Gulf of Mexico has resulted in a rather disturbed pattern across the southeast. Based on the latest RAP analysis, it appears as though there is very little synoptic scale forcing with this system and most of the convection is being generated by various surface features. Two convergent zones, one across the Florida peninsula, and another across the Mississippi Valley are responsible for the associated convection. Elsewhere, showers and thunderstorms in the Gulf are associated with the wave axis. Convection will continue in the three aforementioned regions through the rest of the evening and is expected to remain rather benign. Showers and thunderstorms will diminish over land by midnight, with convection ongoing across our marine zones through the night. The threat for waterspouts will exist overnight closer to the coast. && .SHORT TERM [Tuesday Through Wednesday Night]... PoPs will be somewhat tricky during the next couple of days as we gradually transition into a more typical Sea Breeze Pattern, with the weak Tropical Wave in the northern Gulf of Mexico slowly exiting to our west. Went with 30-40% PoPs from N-S on Tuesday with, with fairly high 40-50% PoPs on Wednesday for a Type 8 Sea Breeze Regime Day, which is characterized by a 5 to 10kt Mean Layer Vector Wind (MLVW) between 1000-700mb. However, this Regime typically has a fairly late start to the convection, and with Upper Level Ridging beginning to build in from the NW, High Temperatures are expected to reach the mid to upper 90s away from the coast. These temperatures, combined with fairly high dewpoints, may result in Apparent Temperatures that reach Heat Advisory levels (103 to 108 degrees) across a good portion of the interior of our CWA. && .LONG TERM [Thursday through Monday]... The long term period begins aloft with the ridge in place across the Southeast flattening and eventually weakening by the weekend as a trough builds across the Mid Atlantic down the Eastern Seaboard. Through Friday, the primary forcing mechanism for showers and thunderstorms looks to be the sea breeze circulation. The pattern of a weakening ridge supports rain chances at or just above climatological values. By Saturday, the East Coast trough amplifies as a piece of energy moves into the Carolinas forcing a weak frontal boundary toward the Gulf Coast. This boundary will provide additional forcing for afternoon storms. Daytime temperatures throughout the period will initially be above normal (mid to upper 90s), especially Thursday and Friday. However, a slight downward trend is expected late in the period with temperatures returning more toward normal. && .AVIATION [Beginning 22Z Monday]... Prevailing VFR conditions are expected through the TAF cycle. Flight restrictions are likely within scattered afternoon storms. Expect a similar scattering of storms tomorrow with prevailing VFR conditions once again. && .MARINE... A weak Tropical Wave across the northeastern Gulf of Mexico will keep elevated chances for showers and thunderstorms through at least tonight. However, outside of any local enhancements due to showers and thunderstorms and the afternoon Sea Breeze, winds and seas are expected to remain fairly low for the next several days as a ridge of high pressure builds into the eastern Gulf. && .FIRE WEATHER... With low level south to southwesterly flow persisting through much of this week, moisture levels are expected to remain safely above critical thresholds, inhibiting red flag criteria, despite some very high temperatures on Wednesday. && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ MESOSCALE UPDATE...Harrigan NEAR TERM...Harrigan SHORT TERM...Gould LONG TERM...Godsey AVIATION...Harrigan MARINE...Gould FIRE WEATHER...Block
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
340 PM EDT Mon Jul 23 2012 .NEAR TERM [Through Tonight]... A tropical wave positioned in the extreme eastern Gulf of Mexico has resulted in a rather disturbed pattern across the southeast. Based on the latest RAP analysis, it appears as though there is very little synoptic scale forcing with this system and most of the convection is being generated by various surface features. Two convergent zones, one across the Florida peninsula, and another across the Mississippi Valley are responsible for the associated convection. Elsewhere, showers and thunderstorms in the Gulf are associated with the wave axis. Convection will continue in the three aforementioned regions through the rest of the afternoon. There still remains the potential for strong storms to develop within the westernmost convergent zone. This is where thermodynamic parameters appear to be favorable for strong (sub-severe) wind gusts. Hail will likely not be an issue this afternoon as mid-levels have warmed a few degrees from yesterday afternoon where only a few instances of sub-severe hail were noted. The primary threat region will be across SE Alabama and portions of the Florida panhandle. Elsewhere, convection is expected to remain rather benign. Showers and thunderstorms will diminish over land by midnight, with convection ongoing across our marine zones through the night. The threat for waterspouts will exist overnight closer to the coast. && .SHORT TERM [Tuesday Through Wednesday Night]...PoPs will be somewhat tricky during the next couple of days as we gradually transition into a more typical Sea Breeze Pattern, with the weak Tropical Wave in the northern Gulf of Mexico slowly exiting to our west. Went with 30-40% PoPs from N-S on Tuesday with, with fairly high 40-50% PoPs on Wednesday for a Type 8 Sea Breeze Regime Day, which is characterized by a 5 to 10kt Mean Layer Vector Wind (MLVW) between 1000-700mb. However, this Regime typically has a fairly late start to the convection, and with Upper Level Ridging beginning to build in from the NW, High Temperatures are expected to reach the mid to upper 90s away from the coast. These temperatures, combined with fairly high dewpoints, may result in Apparent Temperatures that reach Heat Advisory levels (103 to 108 degrees) across a good portion of the interior of our CWA. && .LONG TERM [Thursday through Monday]... The long term period begins aloft with the ridge in place across the Southeast flattening and eventually weakening by the weekend as a trough builds across the Mid Atlantic down the Eastern Seaboard. Through Friday, the primary forcing mechanism for showers and thunderstorms looks to be the sea breeze circulation. The pattern of a weakening ridge supports rain chances at or just above climatological values. By Saturday, the East Coast trough amplifies as a piece of energy moves into the Carolinas forcing a weak frontal boundary toward the Gulf Coast. This boundary will provide additional forcing for afternoon storms. Daytime temperatures throughout the period will initially be above normal (mid to upper 90s), especially Thursday and Friday. However, a slight downward trend is expected late in the period with temperatures returning more toward normal. && .AVIATION... Prevailing VFR conditions are expected through the TAF cycle. Flight restrictions are likely within scattered afternoon storms. Expect a similar scattering of storms tomorrow with prevailing VFR conditions once again. && .MARINE... A weak Tropical Wave across the northeastern Gulf of Mexico will keep elevated chances for showers and thunderstorms through at least tonight. However, outside of any local enhancements due to showers and thunderstorms and the afternoon Sea Breeze, winds and seas are expected to remain fairly low for the next several days as a ridge of high pressure builds into the eastern Gulf. && .FIRE WEATHER...With low level south to southwesterly flow persisting through much of this week, moisture levels are expected to remain safely above critical thresholds, inhibiting red flag criteria, despite some very high temperatures on Wednesday. && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Harrigan SHORT TERM...Gould LONG TERM...Godsey AVIATION...Harrigan MARINE...Gould FIRE WEATHER...Block
AREA FORECAST DISCUSSION
NWS MIAMI FL
150 PM EDT MON JUL 23 2012 .AVIATION... WIDESPREAD AREA OF SHOWERS AND THUNDERSTORMS THAT PUSHED NORTH ACROSS THE ATLANTIC WATERS THIS MORNING HAVE SUPPRESSED THE INLAND INSURGENCE OF THE EAST COAST SEA BREEZE. AS A RESULT...THE ONLY DEVELOPMENT THUS FAR THIS AFTERNOON HAS BEEN ACROSS INTERIOR AND WESTERN AREAS. MOST OF THE ACTIVITY IS NOW WELL NORTHEAST OF KAPF AND CONTINUES TO PUSH TO THE NORTH- NORTHEAST. LATEST HRRR GUIDANCE DOES DEPICT ADDITIONAL DEVELOPMENT ALONG PALM BEACH AND BROWARD COUNTIES OVER THE NEXT COUPLE OF HOURS AS CLOUD COVER IN THESE AREAS HAS NOW SCATTERED OUT. OTHERWISE...MAINLY VFR CONDITIONS WILL PREVAIL. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 78 89 78 91 / 20 20 10 20 FORT LAUDERDALE 79 90 80 90 / 20 20 10 20 MIAMI 78 91 79 92 / 20 20 10 20 NAPLES 77 91 76 90 / 20 20 10 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MIAMI FL
1000 AM EDT MON JUL 23 2012 .UPDATE...A TROPICAL WAVE OVER THE ERN GULF OF MEX WILL CONTINUE TO MOVE AWAY FROM THE LOCAL AREA TODAY. CONVERGENT FLOW AT 850-700 MB BEHIND THE WAVE...COUPLED WITH AMPLE MOISTURE...IS CONTRIBUTING TO A LARGE AREA OF MODERATE TO HEAVY RAIN...WITH EMBEDDED THUNDERSTORMS OVER THE ATLANTIC WATERS AND NORTHEAST SECTIONS OF SOUTH FLORIDA THIS MORNING. HOWEVER...DIVERGENT LOW LEVEL FLOW MAY HAVE CONTRIBUTED TO THE LACK OF CLOUDS/PRECIP OVER THE REST OF SOUTH FLORIDA THIS MORNING. BASED ON THIS...DECIDED TO LOWER THE PROBABILITY OF PRECIP (POP) ACROSS MOST OF SOUTH FLORIDA AT LEAST THROUGH LATE MORNING. NEVERTHELESS...WL STILL EXPECT REGENERATION OF SHOWERS/STORMS OVER LAND AS HEATING COMBINES WITH LOCAL BREEZES AND THE ABUNDANT MOISTURE THIS AFTERNOON. CURRENT FORECAST PACKAGE ADDRESSES THIS, THEREFORE NO CHANGES TO THE AFTERNOON FORECAST ARE ANTICIPATED AT THIS TIME. RGH .AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS SOUTH FLORIDA TODAY AS PLENTY OF LOW LEVEL MOISTURE REMAINS IN PLACE. MOST OF THE THUNDERSTORM ACTIVITY REMAINS OVER THE ATLANTIC OCEAN, HOWEVER MORE THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE PENINSULA AS THE DAY PROGRESSES. LEFT A VCTS ACROSS ALL OF THE TAF SITES THROUGH MONDAY. SOUTHEAST WINDS WILL INCREASE TO 10 TO 15 KNOTS DURING THE DAY TODAY. AT KAPF, A WEST COAST SEA BREEZE WILL MOVE IN DURING THE AFTERNOON HOURS SHIFTING THE WINDS SOUTHWEST FOR SEVERAL HOURS. && .PREV DISCUSSION... /ISSUED 310 AM EDT MON JUL 23 2012/ DISCUSSION...AN INVERTED TROUGH HAS BEEN MOVING ACROSS S FL ON SUNDAY AND TONIGHT ENHANCING THE CONVECTION. THE DIURNAL CYCLE HAS ENDED THE ACTIVITY OVER THE MAINLAND BUT STILL HAVE SCT SHRA ALONG WITH A FEW TSRA OVER TH ATLANTIC AND GULF WATERS. MORE RADAR SIGNATURES SHOWING UP OVER THE FL STRAITS WITH THE RAPID REFRESH SHOWING THIS FLARE UP TO CONTINUE ADVANCING NORTH AND SOME EVEN MOVING ONSHORE OF THE E CST REGION. THEREFORE HAVE INDICATED HIGHER POPS THIS MORNING FOR THIS REGION. AS THE TROUGH CONTINUES TO THE NW AWAY FROM S FL, A MID LEVEL RIDGE WILL BUILD IN FROM THE ATLANTIC WITH DRIER AIR ALOFT MOVING ACROSS THE REGION. IN FACT, THE NAM SHOWS THIS DRIER AIR ARRIVING SOONER THAN WHAT THE GFS INDICATES AND POPS COULD BE OVERDONE. HOWEVER, CANNOT IGNORE WHAT IS ONGOING AND THUS THE HRRR SOLUTION SEEMS REASONABLE AT THIS TIME. THE DRIER PATTERN WILL TREND THE POPS DOWN THROUGH THE END OF THIS WEEK. THERE HAD BEEN SOME INDICATION EARLIER THAT MORE SAHARAN DUST COULD ALSO ARRIVE THIS WEEK BUT MODELS DO NOT SHOW THE EXTENT AS WITH THE LAST EPISODE AND WILL CONTINUE TO LEAVE OUT OF THE FCST FOR NOW. IT WOULD THEREFORE APPEAR THAT A RATHER MUNDANE WEATHER PATTERN IS IN STORE THROUGH THE END OF THE WEEK AND IN FACT THE LATEST GFS 00Z RUN SHOWS THE DRIER AIRMASS IN PLACE INTO THE UPCOMING WEEKEND SO THE SLIGHT INCREASE IN POPS FOR THE CURRENT FCST PACKAGE MAY HAVE TO BE SCALED BACK. MARINE...AN EAST TO SOUTHEAST WIND AT LESS THAN 15 KNOTS OVER THE NEXT FEW DAYS WILL YIELD SEAS OF GENERALLY LESS THAN 4 FEET. HOWEVER, SEAS COULD BE HIGHER NEAR STRONGER THUNDERSTORMS. FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 78 89 78 / 60 20 20 10 FORT LAUDERDALE 88 79 90 80 / 60 20 20 10 MIAMI 89 78 91 79 / 60 20 20 10 NAPLES 90 77 91 76 / 50 20 20 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...30/KOB AVIATION/RADAR...55/CWC
AREA FORECAST DISCUSSION
NWS MIAMI FL
729 AM EDT MON JUL 23 2012 .AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS SOUTH FLORIDA TODAY AS PLENTY OF LOW LEVEL MOISTURE REMAINS IN PLACE. MOST OF THE THUNDERSTORM ACTIVITY REMAINS OVER THE ATLANTIC OCEAN, HOWEVER MORE THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE PENINSULA AS THE DAY PROGRESSES. LEFT A VCTS ACROSS ALL OF THE TAF SITES THROUGH MONDAY. SOUTHEAST WINDS WILL INCREASE TO 10 TO 15 KNOTS DURING THE DAY TODAY. AT KAPF, A WEST COAST SEA BREEZE WILL MOVE IN DURING THE AFTERNOON HOURS SHIFTING THE WINDS SOUTHWEST FOR SEVERAL HOURS. && .PREV DISCUSSION... /ISSUED 310 AM EDT MON JUL 23 2012/ DISCUSSION...AN INVERTED TROUGH HAS BEEN MOVING ACROSS S FL ON SUNDAY AND TONIGHT ENHANCING THE CONVECTION. THE DIURNAL CYCLE HAS ENDED THE ACTIVITY OVER THE MAINLAND BUT STILL HAVE SCT SHRA ALONG WITH A FEW TSRA OVER TH ATLANTIC AND GULF WATERS. MORE RADAR SIGNATURES SHOWING UP OVER THE FL STRAITS WITH THE RAPID REFRESH SHOWING THIS FLARE UP TO CONTINUE ADVANCING NORTH AND SOME EVEN MOVING ONSHORE OF THE E CST REGION. THEREFORE HAVE INDICATED HIGHER POPS THIS MORNING FOR THIS REGION. AS THE TROUGH CONTINUES TO THE NW AWAY FROM S FL, A MID LEVEL RIDGE WILL BUILD IN FROM THE ATLANTIC WITH DRIER AIR ALOFT MOVING ACROSS THE REGION. IN FACT, THE NAM SHOWS THIS DRIER AIR ARRIVING SOONER THAN WHAT THE GFS INDICATES AND POPS COULD BE OVERDONE. HOWEVER, CANNOT IGNORE WHAT IS ONGOING AND THUS THE HRRR SOLUTION SEEMS REASONABLE AT THIS TIME. THE DRIER PATTERN WILL TREND THE POPS DOWN THROUGH THE END OF THIS WEEK. THERE HAD BEEN SOME INDICATION EARLIER THAT MORE SAHARAN DUST COULD ALSO ARRIVE THIS WEEK BUT MODELS DO NOT SHOW THE EXTENT AS WITH THE LAST EPISODE AND WILL CONTINUE TO LEAVE OUT OF THE FCST FOR NOW. IT WOULD THEREFORE APPEAR THAT A RATHER MUNDANE WEATHER PATTERN IS IN STORE THROUGH THE END OF THE WEEK AND IN FACT THE LATEST GFS 00Z RUN SHOWS THE DRIER AIRMASS IN PLACE INTO THE UPCOMING WEEKEND SO THE SLIGHT INCREASE IN POPS FOR THE CURRENT FCST PACKAGE MAY HAVE TO BE SCALED BACK. MARINE...AN EAST TO SOUTHEAST WIND AT LESS THAN 15 KNOTS OVER THE NEXT FEW DAYS WILL YIELD SEAS OF GENERALLY LESS THAN 4 FEET. HOWEVER, SEAS COULD BE HIGHER NEAR STRONGER THUNDERSTORMS. FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 78 89 78 / 60 20 20 10 FORT LAUDERDALE 88 79 90 80 / 60 20 20 10 MIAMI 89 78 91 79 / 60 20 20 10 NAPLES 90 77 91 76 / 50 20 20 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...30/KOB AVIATION/RADAR...55/CWC
AREA FORECAST DISCUSSION
NWS MIAMI FL
310 AM EDT MON JUL 23 2012 .DISCUSSION...AN INVERTED TROUGH HAS BEEN MOVING ACROSS S FL ON SUNDAY AND TONIGHT ENHANCING THE CONVECTION. THE DIURNAL CYCLE HAS ENDED THE ACTIVITY OVER THE MAINLAND BUT STILL HAVE SCT SHRA ALONG WITH A FEW TSRA OVER TH ATLANTIC AND GULF WATERS. MORE RADAR SIGNATURES SHOWING UP OVER THE FL STRAITS WITH THE RAPID REFRESH SHOWING THIS FLARE UP TO CONTINUE ADVANCING NORTH AND SOME EVEN MOVING ONSHORE OF THE E CST REGION. THEREFORE HAVE INDICATED HIGHER POPS THIS MORNING FOR THIS REGION. AS THE TROUGH CONTINUES TO THE NW AWAY FROM S FL, A MID LEVEL RIDGE WILL BUILD IN FROM THE ATLANTIC WITH DRIER AIR ALOFT MOVING ACROSS THE REGION. IN FACT, THE NAM SHOWS THIS DRIER AIR ARRIVING SOONER THAN WHAT THE GFS INDICATES AND POPS COULD BE OVERDONE. HOWEVER, CANNOT IGNORE WHAT IS ONGOING AND THUS THE HRRR SOLUTION SEEMS REASONABLE AT THIS TIME. THE DRIER PATTERN WILL TREND THE POPS DOWN THROUGH THE END OF THIS WEEK. THERE HAD BEEN SOME INDICATION EARLIER THAT MORE SAHARAN DUST COULD ALSO ARRIVE THIS WEEK BUT MODELS DO NOT SHOW THE EXTENT AS WITH THE LAST EPISODE AND WILL CONTINUE TO LEAVE OUT OF THE FCST FOR NOW. IT WOULD THEREFORE APPEAR THAT A RATHER MUNDANE WEATHER PATTERN IS IN STORE THROUGH THE END OF THE WEEK AND IN FACT THE LATEST GFS 00Z RUN SHOWS THE DRIER AIRMASS IN PLACE INTO THE UPCOMING WEEKEND SO THE SLIGHT INCREASE IN POPS FOR THE CURRENT FCST PACKAGE MAY HAVE TO BE SCALED BACK. && .MARINE...AN EAST TO SOUTHEAST WIND AT LESS THAN 15 KNOTS OVER THE NEXT FEW DAYS WILL YIELD SEAS OF GENERALLY LESS THAN 4 FEET. HOWEVER, SEAS COULD BE HIGHER NEAR STRONGER THUNDERSTORMS. && .FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 78 89 78 / 60 20 20 10 FORT LAUDERDALE 88 79 90 80 / 60 20 20 10 MIAMI 89 78 91 79 / 60 20 20 10 NAPLES 90 77 91 76 / 50 20 20 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...30/KOB AVIATION/RADAR...55/CWC
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
751 PM EDT TUE JUL 24 2012 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL REMAIN SOUTH OF THE AREA THROUGH THE WEEK AS A TROUGH OF LOW PRESSURE PERSISTS INLAND. A WEAK COLD FRONT MAY APPROACH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... A WEAK SURFACE TROUGH EXTENDS FROM SOUTHWEST GEORGIA THROUGH THE EASTERN MIDLANDS INTO COASTAL NORTH CAROLINA. SCATTERED SHOWERS AND TSTMS HAVE RECENTLY POPPED IN THE VICINITY OF THIS FEATURE WITH THE LARGEST CONCENTRATION OCCURRING NEAR VIDALIA. WHILE THIS ACTIVITY MAY LINGER FOR ANOTHER FEW HOURS WITHIN AN AXIS OF MODEST INSTABILITY...WEAK SHEAR AND THE LACK OF AN UPPER LEVEL FORCING MECHANISM SUGGESTS MOST OF THIS SHOULD DISSIPATE NEAR OR JUST AFTER SUNSET. FARTHER UPSTREAM...OUTFLOW GENERATED BY A LARGE MESOSCALE CONVECTIVE SYSTEM /MCS/ MOVING THROUGH EASTERN NORTH CAROLINA WAS MOVING SOUTH INTO THE SOUTH CAROLINA UPSTATE AND NORTHERN MIDLANDS. SECONDARY OUTFLOW ASSOCIATED WITH CONVECTION MOVING THROUGH THE NORTH CAROLINA MOUNTAINS WAS ALSO MOVING QUICKLY SOUTH. BOTH ARE EXPECTED TO MERGE AND POTENTIALLY REFIRE A SECONDARY AREA OF CONVECTION LATER THIS EVENING ACROSS CENTRAL AND NORTHERN SOUTH CAROLINA AS SHORTWAVE ENERGY EMBEDDED IN THE NORTHWEST FLOW ALOFT MOVES ACROSS NORTH CAROLINA. WHILE IT REMAINS TO BE SEEN HOW THIS POTENTIAL SECONDARY MCS WILL EVOLVE...SEVERAL HIGHER RESOLUTION MESOSCALE MODELS SUGGEST SCATTERED SHOWERS/TSTMS WILL IMPACT PARTS OF SOUTHERN SOUTH CAROLINA. WITH MODEST INSTABILITY IN PLACE AND RAP SHEAR PROFILES SHOWING 0-6KM BULK SHEAR INCREASE TO NEAR 30 KT ACROSS THE MIDLANDS AFTER SUNSET...SUSPECT THERE IS A REASONABLE CHANCE THAT SOME SORT OF MCS COULD MAKE IT INTO PARTS OF THE LOCAL FORECAST AREA LATER THIS EVENING...ESPECIALLY SHOULD A COLD POOL DEVELOP WITH UPSTREAM CONVECTION. WILL CONTINUE WITH A 20-50 POP REGIME FOR THE EVENING HOURS WITH THE HIGHEST POPS CLUSTERED OVER THE CHARLESTON TRI-COUNTY AREA. WILL ALSO KEEP A MENTION OF LARGE HAIL AND DAMAGING WINDS IN THE VARIOUS GRIDDED PRODUCTS...MAINLY FROM COLLETON COUNTY NORTH INTO THE CHARLESTON AND MONCKS CORNER AREAS. POPS WILL DROP OFF TO SLIGHT CHANCE AFTER MIDNIGHT FOR ALL AREAS. FURTHER REFINEMENTS WILL BE NEEDED AS THE EVENING PROGRESSES AND SHORT TERM MESOSCALE TRENDS BECOME MORE APPARENT. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... THE 500 MB RIDGE AXIS IS PROGGED TO SHIFT OVER THE AREA ON WEDNESDAY AND OFF THE EASTERN SEABOARD THURSDAY AND FRIDAY...ALLOWING THE INLAND TROUGH TO STRENGTHEN. LOW-LEVELS WILL REMAIN VERY MOIST THROUGH THE PERIOD WITH DEWPOINTS REMAINING IN THE MIDDLE 70S. THE SEABREEZE LOOKS TO REMAIN PINNED NEAR THE COAST UNTIL LATER IN THE AFTERNOONS DUE TO A DEEP WEST SOUTHWEST FLOW. HIGH TEMPS WILL REMAIN ABOVE NORMAL WITH HIGHS IN THE MID AND UPPER 90S EACH DAY. CONVECTION WILL LIKELY TAKE UNTIL EARLY AFTERNOON TO BEGIN POPPING DUE TO A STRONG CAP IN PLACE. HEAT ADVISORY CONDITIONS MAY BE REACHED IN SOME PLACES THURSDAY OR FRIDAY DUE TO VALUES REACHING 110F FOR 2-3 HOURS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... THE GREAT LAKES SHORT WAVE MOVES INTO THE NE SATURDAY...WHICH AMPLIFIES THE TROUGH IN THE EAST. THE APEX OF THIS TROUGH STRETCHES SOUTH TO GA/FL...AND IT MOVES LITTLE THROUGH SUNDAY. BEYOND THAT FOR EARLY NEXT WEEK WE/RE NOT YET CERTAIN AS TO WHETHER OR NOT ADDITIONAL SHORT WAVES DROP INTO THE TROUGH TO MAINTAIN ITS PLACE OVER THE EAST AND SE...OR DOES IT REMAIN VOID OF ANY PERTURBATIONS AND INSTEAD BEGINS TO LIFT OUT. AT THE SURFACE OUR CONFIDENCE IS GOOD THAT THE INLAND TROUGH WILL REMAIN NOT FAR FROM THE LOCAL AREA THROUGH THE WEEKEND. BUT THEN THE QUESTION REMAINS IS TO WHETHER OR NOT A COLD FRONT IS ABLE TO REACH THE FORECAST AREA EARLY NEXT WEEK. CLIMATOLOGY WOULD SUGGEST THE FRONT NEVER GETS THIS FAR SE...SO THIS REMAINS TO BE SEEN. RAIN CHANCES WILL BE IN THE ISOLATED TO SCATTERED RANGE OVER THE WEEKEND...THEN WE PREFER NOTHING MORE THAN ISOLATED COVERAGE MONDAY AND TUESDAY SINCE OUR CONFIDENCE LOWERS. TEMPS WILL REMAIN ABOVE SEASONAL LEVELS SATURDAY AND SUNDAY...TRENDING BACK CLOSER TO NORMAL MONDAY AND TUESDAY. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... KCHS...VFR CONDITIONS WILL PERSIST OVER THE NEXT HOUR OR TWO BEFORE THE POSSIBILITY OF MVFR CIGS/VSBYS INCREASES WITH SHOWERS AND THUNDERSTORMS EARLY TONIGHT. RECENT TRENDS INDICATE A CHANCE OF SHOWERS/THUNDERSTORMS ADVANCING TO THE CHS TERMINAL AROUND 01Z AND LASTING A FEW HOURS BEFORE SHIFTING FURTHER SOUTHEAST. HAVE THEREFORE MAINTAINED VCTS FROM 01-05Z AT THE CHS TERMINAL. SHOULD CONFIDENCE OF SHOWERS AND THUNDERSTORMS INCREASE OVER THE NEXT 2 HOURS...WILL LIKELY NEED TO INCLUDE AT LEAST TEMPO MVFR CIGS/VSBYS AT THE CHS TERMINAL FOR A COUPLE HOUR PERIOD. VFR CIGS/VSBYS ARE THEN EXPECTED TO PREVAIL BY 05Z SHOULD ACTIVITY MAKE IT TO THE TERMINAL AND WILL LIKELY CONTINUE THROUGH 00Z THURSDAY. KSAV...VFR CONDITIONS ARE EXPECTED THROUGH 00Z THURSDAY. EXTENDED AVIATION OUTLOOK...DIURNAL SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE WEEK. && .MARINE... TONIGHT...THE LOCAL WATERS WILL CONTINUE TO BE POSITIONED IN AN AREA BETWEEN THE INLAND TROUGH OF LOW PRESSURE AND SUBTROPICAL HIGH OVER THE ATLANTIC. THIS WILL MAINTAIN THE RELATIVELY TIGHT PRESSURE GRADIENT AND KEEP THE LOW-LEVEL SW FLOW ELEVATED. WINDS WILL MAINLY REMAIN BELOW 20 KT...HIGHEST ACROSS THE SC WATERS. SEAS WILL RUN 2-4 FT WITHIN 20 NM...AND 4-5 FT BEYOND. THUNDERSTORMS MAY MOVE INTO PORTIONS OF THE WATERS THIS EVENING...ESPECIALLY THE SC WATERS...SOME OF WHICH WILL BE STRONG OR EVEN SEVERE WITH DAMAGING WINDS AND FREQUENT LIGHTNING THE MAIN HAZARDS. WEDNESDAY THROUGH SUNDAY...THE GRADIENT WILL RELAX A BIT ON WEDNESDAY BUT TIGHTEN AGAIN THURSDAY INTO FRIDAY AS ATLANTIC HIGH PRESSURE STRENGTHENS TO OUR EAST AND THE INLAND TROUGH DEEPENS. CONDITIONS LOOK TO REMAIN BELOW SMALL CRAFT CRITERIA BUT WE COULD SEE SOME SOLID 15-20 KTS DURING OVERNIGHT SURGES AND THE COASTAL SEABREEZE COULD EXCEED 15 KT AT TIMES DURING THE AFTERNOONS. SEAS WILL BE A MIXTURE OF SHORT PERIOD WIND DRIVEN WAVES AND LONGER PERIOD SWELL WAVES...WITH THE RESULTING COMBINED SEAS MOSTLY HELD AT OR BELOW 4 OR 5 FT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...JRL LONG TERM... AVIATION...DPB MARINE...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
606 PM EDT MON JUL 23 2012 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL DROP SOUTH THROUGH THE WEEK AS A TROUGH OF LOW PRESSURE LINGERS INLAND. A WEAK COLD FRONT MAY APPROACH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... INLAND CONVECTION THAT HAS FIRED ALONG THE LEE-SIDE TROUGH IS SLOWLY WANING AS IT DRIFTS SOUTHEAST. THIS WEAKENING IS LIKELY DUE TO THE INCREASING INFLUENCES OF MEAN RIDGING ACROSS SOUTHERN SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH POSSIBLY SOME INFLUENCES FROM THE SAHARAN AIR LAYER /SAL/ THAT HAS BEEN IN PLACE SINCE YESTERDAY. 23/20Z RAP SOUNDINGS INDICATE MODEST CAPPING WILL REMAIN IN PLACE FOR THE NEXT SEVERAL HOURS SO CONTINUED WEAKENING OF UPSTREAM CONVECTION IS EXPECTED. AM LITTLE HESITANT TO REMOVE POPS COMPLETELY ACROSS THE FAR INLAND ZONES WITH WATER VAPOR IMAGERY SHOWING A WEAK SHORTWAVE JUST NOW ENTERING WESTERN NORTH CAROLINA. THIS FEATURE IS PROGGED TO MOVE ACROSS NORTH CAROLINA THIS EVENING...EXITING OFF THE CRYSTAL COAST AFTER MIDNIGHT. THIS MAY PROVIDE JUST ENOUGH LIFT TO ALLOW ISOLATED CONVECTION TO MOVE INTO THE NORTHERN ZONES LATER THIS EVENING. WILL MAINTAIN SLIGHT CHANCE POPS ACROSS FAR INLAND AND NORTHERN AREAS THROUGH THIS EVENING. SUBTROPICAL HIGH PRESSURE WILL EXTEND ACROSS THE REGION OVERNIGHT AS THE CORE OF UPPER RIDGE SHIFTS INTO THE CENTRAL PLAINS. LINGERING CONVECTION WILL GRADUALLY DIMINISH THIS EVENING AS WEAK SHORTWAVE ENERGY PASSES OFF TO THE NORTH. THE REGION WILL SEE YET ANOTHER DRY AND HUMID NIGHT WITH LOWS RANGING FROM THE MID 70S INLAND TO THE LOWER 80S AT THE BEACHES AND DOWNTOWN CHARLESTON. CONVECTIVE DEBRIS CLOUDINESS WILL GRADUALLY THIN WITH TIME WITH MOSTLY CLEAR SKIES EXPECTED. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... THE MID/UPPER-LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN CENTERED WEST OF THE LOCAL AREA THROUGH WEDNESDAY...ALTHOUGH IT WILL BE WEAKENING WITH TIME AS UPPER SHORTWAVES MOVE THROUGH THE GREAT LAKES. THE HIGH WILL THEN SHIFT OVER THE AREA THURSDAY. MEANWHILE...THE SURFACE ATLANTIC RIDGE WILL ALSO SHIFT SOUTH AND EAST OF THE AREA THROUGH THE PERIOD WHILE A TROUGH OF LOW PRESSURE GENERALLY REMAINS INLAND. RAIN CHANCES WILL REMAIN LOW AND RATHER TYPICAL FOR THIS TIME OF YEAR...WITH THE BEST CHANCES LIKELY IN THE AFTERNOON AND EVENING. WILL HAVE TO WATCH FOR THE POTENTIAL OF AN ORGANIZED CLUSTER OF STORMS FORMING UPSTREAM WHERE BULK SHEAR IS STRONGER AND HEADING SOUTHEAST TOWARD THE AREA LATER TUESDAY. TEMPERATURES WILL LIKELY BE THE BIGGER STORY THIS PERIOD AS LOW-LEVEL THICKNESSES INCREASE AND THE FLOW REMAINS MAINLY OFFSHORE REACHING AT LEAST THE MID 90S INLAND TUESDAY AND MID/UPPER 90S WEDNESDAY AND THURSDAY. IN ADDITION...INCREASING DEWPOINTS WILL YIELD HEAT INDICES NEAR 110 DEGREES WEDNESDAY AND THURSDAY...AND THUS THE POTENTIAL FOR HEAT ADVISORIES. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A DECENT SHORT WAVE WILL MOVE THROUGH THE GREAT LAKES ON FRIDAY AND CAUSE ANOTHER MID LEVEL TROUGH TO FORM OVER THE EASTERN PART OF THE COUNTRY. THIS TROUGH WILL SHARPEN SLIGHTLY INTO THE WEEKEND...WITH THE PIEDMONT TROUGH REMAINING IN PLACE. EVENTUALLY THE CONTINUED NW FLOW ALOFT MAY ALLOW FOR A WEAK COLD FRONT TO APPROACH EARLY NEXT WEEK...ALTHOUGH CLIMATOLOGICALLY THIS SEEMS UNLIKELY. FOR NOW OUR POP FORECAST WILL GO NO HIGHER THAN 20-30 PERCENT. WITH 850 MB TEMPS FORECAST AS HIGH AS NEAR 21C FRIDAY AND SATURDAY...TEMPS WILL BE WELL INTO THE 90S...BEFORE A LITTLE MORE MODERATED AIR MOVES IN SUNDAY AND MONDAY TO DROP TEMPS A FEW DEGREES. HEAT ADVISORIES MAY BE REQUIRED FRIDAY AND SATURDAY...WITH HEAT INDICES OF 110 DEGREES OR MORE YET AGAIN POSSIBLE. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... VFR FOR THE NEXT 24 HOURS. ISOLATED TSTMS ARE POSSIBLE TUESDAY AFTERNOON. PROBABILITIES ARE TOO LOW TO INCLUDE A MENTION AT KCHS/KSAV ATTM. EXTENDED AVIATION OUTLOOK...DIURNAL SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE WEEK. && .MARINE... THE SUBTROPICAL HIGH PRESSURE WILL MAINTAIN A SOUTH TO SOUTHWEST FLOW ACROSS THE MARINE AREA. EXPECT WINDS TO INCREASE SLIGHTLY THIS EVENING AND INTO THE OVERNIGHT AS THE PRESSURE GRADIENT TIGHTENS IN RESPONSE TO A DEVELOPING INLAND TROUGH. OVERALL...EXPECT WINDS TO REMAIN NO MORE THAN 15 TO 20 KNOTS OVERNIGHT...MAINLY ACROSS THE SC WATERS AND BEACHES. SEAS WILL INCREASE IN ASSOCIATION WITH THE SURGING WINDS...BUT HAVE CAPPED SEAS AT 5 FT BEYOND 20 NM. WITHIN 20 NM...EXPECT NO MORE THAN 2 TO 4 FOOT SEAS. TUESDAY THROUGH SATURDAY...THE SUBTROPICAL ATLANTIC RIDGE WILL BE SUPPRESSED TO THE SOUTH ACROSS FLORIDA...AS THE LEE SIDE TROUGH REMAINS INLAND IN VARYING DEGREES OF STRENGTH AND IN PROXIMITY TO THE COAST OF THE SE. FOR THE MOST PART WINDS WILL BE SOUTHWESTERLY AT LESS THAN 15 OR 20 KT THROUGH LATE THIS WEEK. SEAS WILL GENERALLY HOLD AT 4 FEET OR LESS...A MIXTURE OF BOTH WIND DRIVEN WAVES AND SMALL SWELLS. WHILE IT IS DIFFICULT TO PINPOINT EXACTLY WHEN T-STORMS WILL OCCUR...WITH AN OFFSHORE STEERING FLOW TO PREVAIL THROUGH THE MID AND LATE WEEK...MARINERS ARE ADVISED THAT PERIODIC STRONG OR SEVERE T-STORMS MAY OCCUR. RIP CURRENTS...THERE WILL BE A MODERATE RISK FOR RIP CURRENTS AT THE SOUTH CAROLINA BEACHES TUESDAY DUE TO LINGERING SWELLS AND BREEZY CONDITIONS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...RJB LONG TERM...BSH AVIATION... MARINE...
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
200 PM EDT MON JUL 23 2012 .UPDATE... NO CHANGES PLANNED THIS MORNING. TEMPERATURES SEEM TO BE ON TRACK. 41 .PREVIOUS... .SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... /ISSUED AT 425 AM EDT MON JUL 23 2012/ PATCHY FOG THIS MORNING SHOULD REMAIN ABOVE DENSE LEVELS AND QUICKLY BURN OFF AROUND SUNRISE. STRONG MID AND UPPER LEVEL RIDGING WILL DOMINATE THE NEXT COUPLE OF DAYS... RESULTING IN LOWER TO MID 90 DEGREE HIGH TEMPERATURES FOR TODAY...THEN MID AND UPPER 90S ON TUESDAY. EXPECTING MAINLY DIURNALLY DRIVEN ISOLATED TO LOW SCATTERED LATE AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS THROUGH THE SHORT TERM. THE GFS AND HRRR MODELS INDICATE A DISTURBANCE RIDING DOWN THE NORTHEAST PERIPHERY OF THE UPPER RIDGE MAY SPARK A FEW STORMS OVER NORTHEAST GA LATER TODAY. HOWEVER... EXPECT THE GREATER THUNDERSTORM THREAT TO BE GENERALLY ALONG AND SOUTH OF A ROME TO ATLANTA TO DUBLIN LINE WHERE THE STRONGER MOISTURE CONVERGENCE AND SEA BREEZE FRONT COULD PROVIDE SUFFICIENT LIFT TO BREAK THE MID LEVEL CAP. ANY DEVELOPMENT WILL LIKELY BE LATE IN THE AFTERNOON...AS WAS SEEN ON SUNDAY... AND WITH CAPE VALUES IN THE 2000-2500 J/KG RANGE... A FEW STORMS COULD BECOME STRONG. THE MAIN THREATS FROM THE STRONGER STORMS WILL BE FREQUENT LIGHTNING AND WIND GUSTS TO 50 MPH THAT COULD KNOCK DOWN A FEW TREES. ALTHOUGH THE DRIER AIR MASS WILL ENHANCE THE WIND GUST THREAT... IT SHOULD LESSON THE FLASH FLOOD THREAT. ISOLATED STORMS MAY LINGER THROUGH THE EVENING... BUT CONVECTIVE ACTIVITY SHOULD DISSIPATE BY MIDNIGHT OR SHORTLY AFTER. AS FOR TEMPS... HAVE LEANED TOWARD THE WARMER GUIDANCE FOR HIGHS AND TOOK A MAV AND MET BLEND FOR LOWS THROUGH THE SHORT TERM. 39 .LONG TERM /WEDNESDAY THROUGH SUNDAY/... /ISSUED AT 425 AM EDT MON JUL 23 2012/ HIGH PRESSURE RIDGE OVER THE AREA WILL CONTINUE TO DOMINATE THE WEATHER PATTERN INTO THE LONG TERM. A DECENT AMOUNT OF MOISTURE REMAINS OVER THE AREA AS THE RIDGE KEEP THE STATE IN MOIST W TO SW FLOW THROUGH DAY 6-7. ALL IN ALL WILL CONTINUE WITH A PERSISTENCE FORECAST OF DIURNALLY DRIVEN THUNDERSTORMS THROUGH THE END OF THE FORECAST PERIOD. THE GFS MODEL IS SHOWING A COLD FRONT MOVING INTO THE AREA SAT PULLING IN DRIER AIR BEHIND IT FOR NEXT WEEKEND. THIS IS THE FIRST RUN THIS IS SHOWING UP IN SO NOT VERY CONFIDENT IN THIS HAPPENING RIGHT NOW. WILL CONTINUE WITH PERSISTENCE BUT DEFINITELY KEEP AN EYE ON HOW THIS PROGRESSES OVER THE NEXT FEW DAYS. PRECIPITABLE WATER VALUES STILL SHOWING NEAR 1.5 TO 2.0 INCH SO HEAVY RAIN WITH LOCALIZED FLOODING WILL STILL BE A CONCERN...AT LEAST THROUGH WED/THU. 01 && .AVIATION... 18Z UPDATE... VFR CONDITIONS WILL PREVAIL UNDER HIGH PRESSURE INFLUENCE. EXPECT SCT CUMULUS AROUND 040 TO 050 DURING THE AFTERNOON AND EARLY EVENING. ISOLATED TO SCATTERED CONVECTION STILL EXPECTED DURING AFTERNOON HEATING. WINDS EXPECTED TO BE WEST TO NORTHWEST LESS THAN 10KT THIS AFTERNOON BUT COULD VARY IN DIRECTION DUE TO INFLUENCE OF HIGH PRESSURE. MOSTLY CLEAR SKIES TONIGHT WITH NO SIGNIFICANT VISIBILITY RESTRICTIONS AND LIGHT AND VARIABLE WIND. SIMILAR CONDITIONS FOR TUESDAY AFTERNOON. //ATL CONFIDENCE...18Z UPDATE... MEDIUM ON THUNDERSTORM COVERAGE AND IMPACT ON TAF SITES. HIGH ON ALL OTHER ELEMENTS. 41 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 94 72 96 73 / 20 20 30 20 ATLANTA 95 74 95 76 / 30 30 30 20 BLAIRSVILLE 89 68 91 69 / 20 20 30 20 CARTERSVILLE 94 69 95 71 / 30 30 30 20 COLUMBUS 95 73 95 75 / 30 30 30 30 GAINESVILLE 93 73 94 75 / 30 20 30 20 MACON 95 72 95 73 / 30 30 30 20 ROME 95 70 97 72 / 30 30 30 20 PEACHTREE CITY 94 69 94 71 / 30 30 30 20 VIDALIA 96 75 96 77 / 30 30 20 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...41 LONG TERM....01 AVIATION...41
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1100 AM EDT MON JUL 23 2012 .UPDATE... NO CHANGES PLANNED THIS MORNING. TEMPERATURES SEEM TO BE ON TRACK. 41 .PREVIOUS... .SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... /ISSUED AT 425 AM EDT MON JUL 23 2012/ PATCHY FOG THIS MORNING SHOULD REMAIN ABOVE DENSE LEVELS AND QUICKLY BURN OFF AROUND SUNRISE. STRONG MID AND UPPER LEVEL RIDGING WILL DOMINATE THE NEXT COUPLE OF DAYS... RESULTING IN LOWER TO MID 90 DEGREE HIGH TEMPERATURES FOR TODAY...THEN MID AND UPPER 90S ON TUESDAY. EXPECTING MAINLY DIURNALLY DRIVEN ISOLATED TO LOW SCATTERED LATE AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS THROUGH THE SHORT TERM. THE GFS AND HRRR MODELS INDICATE A DISTURBANCE RIDING DOWN THE NORTHEAST PERIPHERY OF THE UPPER RIDGE MAY SPARK A FEW STORMS OVER NORTHEAST GA LATER TODAY. HOWEVER... EXPECT THE GREATER THUNDERSTORM THREAT TO BE GENERALLY ALONG AND SOUTH OF A ROME TO ATLANTA TO DUBLIN LINE WHERE THE STRONGER MOISTURE CONVERGENCE AND SEA BREEZE FRONT COULD PROVIDE SUFFICIENT LIFT TO BREAK THE MID LEVEL CAP. ANY DEVELOPMENT WILL LIKELY BE LATE IN THE AFTERNOON...AS WAS SEEN ON SUNDAY... AND WITH CAPE VALUES IN THE 2000-2500 J/KG RANGE... A FEW STORMS COULD BECOME STRONG. THE MAIN THREATS FROM THE STRONGER STORMS WILL BE FREQUENT LIGHTNING AND WIND GUSTS TO 50 MPH THAT COULD KNOCK DOWN A FEW TREES. ALTHOUGH THE DRIER AIR MASS WILL ENHANCE THE WIND GUST THREAT... IT SHOULD LESSON THE FLASH FLOOD THREAT. ISOLATED STORMS MAY LINGER THROUGH THE EVENING... BUT CONVECTIVE ACTIVITY SHOULD DISSIPATE BY MIDNIGHT OR SHORTLY AFTER. AS FOR TEMPS... HAVE LEANED TOWARD THE WARMER GUIDANCE FOR HIGHS AND TOOK A MAV AND MET BLEND FOR LOWS THROUGH THE SHORT TERM. 39 .LONG TERM /WEDNESDAY THROUGH SUNDAY/... /ISSUED AT 425 AM EDT MON JUL 23 2012/ HIGH PRESSURE RIDGE OVER THE AREA WILL CONTINUE TO DOMINATE THE WEATHER PATTERN INTO THE LONG TERM. A DECENT AMOUNT OF MOISTURE REMAINS OVER THE AREA AS THE RIDGE KEEP THE STATE IN MOIST W TO SW FLOW THROUGH DAY 6-7. ALL IN ALL WILL CONTINUE WITH A PERSISTENCE FORECAST OF DIURNALLY DRIVEN THUNDERSTORMS THROUGH THE END OF THE FORECAST PERIOD. THE GFS MODEL IS SHOWING A COLD FRONT MOVING INTO THE AREA SAT PULLING IN DRIER AIR BEHIND IT FOR NEXT WEEKEND. THIS IS THE FIRST RUN THIS IS SHOWING UP IN SO NOT VERY CONFIDENT IN THIS HAPPENING RIGHT NOW. WILL CONTINUE WITH PERSISTENCE BUT DEFINITELY KEEP AN EYE ON HOW THIS PROGRESSES OVER THE NEXT FEW DAYS. PRECIPITABLE WATER VALUES STILL SHOWING NEAR 1.5 TO 2.0 INCH SO HEAVY RAIN WITH LOCALIZED FLOODING WILL STILL BE A CONCERN...AT LEAST THROUGH WED/THU. 01 && .AVIATION... 12Z UPDATE... VFR CONDITIONS WILL PREVAIL UNDER HIGH PRESSURE INFLUENCE. EXPECT SCT CU TO DEVELOP BY 17-19Z. ISOLATED TO LOW SCATTERED CONVECTION STILL EXPECTED DURING LATE AFTERNOON HEATING. WILL CONTINUE TO SHOW PROB30 22-24Z AT ALL TAF SITES FOR NOW. CALM OR L&V WIND THIS MORNING WILL MIX OUT WSW BY 14-15Z... THEN BACK MORE SSW BY 18-19Z THIS AFTERNOON...WITH SPEEDS GENERALLY LESS THAN 10 KTS. EXPECT SKC TONIGHT WITH NO SIGNIFICANT VIS RESTRICTIONS AND A LIGHT SW WIND. WINDS MIX OUT MORE WESTERLY BY 15Z TUE AROUND 8KTS...WITH A LOW CHANCE OF TSRA ONCE AGAIN LATE TUE AFTERNOON. //ATL CONFIDENCE...12Z UPDATE... HIGH ON ALL ELEMENTS. 39 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 94 72 96 73 / 20 20 30 20 ATLANTA 95 74 95 76 / 30 30 30 20 BLAIRSVILLE 89 68 91 69 / 20 20 30 20 CARTERSVILLE 94 69 95 71 / 30 30 30 20 COLUMBUS 95 73 95 75 / 30 30 30 30 GAINESVILLE 93 73 94 75 / 30 20 30 20 MACON 95 72 95 73 / 30 30 30 20 ROME 95 70 97 72 / 30 30 30 20 PEACHTREE CITY 94 69 94 71 / 30 30 30 20 VIDALIA 96 75 96 77 / 30 30 20 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...39 LONG TERM....01 AVIATION...39
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
725 AM EDT MON JUL 23 2012 .SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... /ISSUED AT 425 AM EDT MON JUL 23 2012/ PATCHY FOG THIS MORNING SHOULD REMAIN ABOVE DENSE LEVELS AND QUICKLY BURN OFF AROUND SUNRISE. STRONG MID AND UPPER LEVEL RIDGING WILL DOMINATE THE NEXT COUPLE OF DAYS... RESULTING IN LOWER TO MID 90 DEGREE HIGH TEMPERATURES FOR TODAY...THEN MID AND UPPER 90S ON TUESDAY. EXPECTING MAINLY DIURNALLY DRIVEN ISOLATED TO LOW SCATTERED LATE AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS THROUGH THE SHORT TERM. ALTHOUGH...THE GFS AND HRRR MODELS INDICATE A DISTURBANCE RIDING DOWN THE NORTHEAST PERIPHERY OF THE UPPER RIDGE MAY SPARK A FEW STORMS OVER NORTHEAST GA LATER TODAY. HOWEVER... EXPECT THE GREATER THUNDERSTORM THREAT TO BE GENERALLY ALONG AND SOUTH OF A ROME TO ATLANTA TO DUBLIN LINE WHERE THE STRONGER MOISTURE CONVERGENCE AND SEA BREEZE FRONT COULD PROVIDE SUFFICIENT LIFT TO BREAK THE MID LEVEL CAP. ANY DEVELOPMENT WILL LIKELY BE LATE IN THE AFTERNOON...AS WAS SEEN ON SUNDAY... AND WITH CAPE VALUES IN THE 2000-2500 J/KG RANGE... A FEW STORMS COULD BECOME STRONG. THE MAIN THREATS FROM THE STRONGER STORMS WILL BE FREQUENT LIGHTNING AND WIND GUSTS TO 50 MPH THAT COULD KNOCK DOWN A FEW TREES. ALTHOUGH THE DRIER AIR MASS WILL ENHANCE THE WIND GUST THREAT... IT SHOULD LESSON THE FLASH FLOOD THREAT. ISOLATED STORMS MAY LINGER THROUGH THE EVENING... BUT CONVECTIVE ACTIVITY SHOULD DISSIPATE BY MIDNIGHT OR SHORTLY AFTER. AS FOR TEMPS... HAVE LEANED TOWARD THE WARMER GUIDANCE FOR HIGHS AND TOOK A MAV AND MET BLEND FOR LOWS THROUGH THE SHORT TERM. 39 .LONG TERM /WEDNESDAY THROUGH SUNDAY/... /ISSUED AT 425 AM EDT MON JUL 23 2012/ HIGH PRESSURE RIDGE OVER THE AREA WILL CONTINUE TO DOMINATE THE WEATHER PATTERN INTO THE LONG TERM. A DECENT AMOUNT OF MOISTURE REMAINS OVER THE AREA AS THE RIDGE KEEP THE STATE IN MOIST W TO SW FLOW THROUGH DAY 6-7. ALL IN ALL WILL CONTINUE WITH A PERSISTENCE FORECAST OF DIURNALLY DRIVEN THUNDERSTORMS THROUGH THE END OF THE FORECAST PERIOD. THE GFS MODEL IS SHOWING A COLD FRONT MOVING INTO THE AREA SAT PULLING IN DRIER AIR BEHIND IT FOR NEXT WEEKEND. THIS IS THE FIRST RUN THIS IS SHOWING UP IN SO NOT VERY CONFIDENT IN THIS HAPPENING RIGHT NOW. WILL CONTINUE WITH PERSISTENCE BUT DEFINITELY KEEP AN EYE ON HOW THIS PROGRESSES OVER THE NEXT FEW DAYS. PRECIPITABLE WATER VALUES STILL SHOWING NEAR 1.5 TO 2.0 INCH SO HEAVY RAIN WITH LOCALIZED FLOODING WILL STILL BE A CONCERN...AT LEAST THROUGH WED/THU. 01 && .AVIATION... 12Z UPDATE... VFR CONDITIONS WILL PREVAIL UNDER HIGH PRESSURE INFLUENCE. EXPECT SCT CU TO DEVELOP BY 17-19Z. ISOLATED TO LOW SCATTERED CONVECTION STILL EXPECTED DURING LATE AFTERNOON HEATING. WILL CONTINUE TO SHOW PROB30 22-24Z AT ALL TAF SITES FOR NOW. CALM OR L&V WIND THIS MORNING WILL MIX OUT WSW BY 14-15Z... THEN BACK MORE SSW BY 18-19Z THIS AFTERNOON...WITH SPEEDS GENERALLY LESS THAN 10 KTS. EXPECT SKC TONIGHT WITH NO SIGNIFICANT VIS RESTRICTIONS AND A LIGHT SW WIND. WINDS MIX OUT MORE WESTERLY BY 15Z TUE AROUND 8KTS...WITH A LOW CHANCE OF TSRA ONCE AGAIN LATE TUE AFTERNOON. //ATL CONFIDENCE...12Z UPDATE... HIGH ON ALL ELEMENTS. 39 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 94 72 96 73 / 20 20 30 20 ATLANTA 95 74 95 76 / 30 30 30 20 BLAIRSVILLE 89 68 91 69 / 20 20 30 20 CARTERSVILLE 94 69 95 71 / 30 30 30 20 COLUMBUS 95 73 95 75 / 30 30 30 30 GAINESVILLE 93 73 94 75 / 30 20 30 20 MACON 95 72 95 73 / 30 30 30 20 ROME 95 70 97 72 / 30 30 30 20 PEACHTREE CITY 94 69 94 71 / 30 30 30 20 VIDALIA 96 75 96 77 / 30 30 20 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...39 LONG TERM....01 AVIATION...39
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
425 AM EDT MON JUL 23 2012 .SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... PATCHY FOG THIS MORNING SHOULD REMAIN ABOVE DENSE LEVELS AND QUICKLY BURN OFF AROUND SUNRISE. STRONG MID AND UPPER LEVEL RIDGING WILL DOMINATE THE NEXT COUPLE OF DAYS... RESULTING IN LOWER TO MID 90 DEGREE HIGH TEMPERATURES FOR TODAY...THEN MID AND UPPER 90S ON TUESDAY. EXPECTING MAINLY DIURNALLY DRIVEN ISOLATED TO LOW SCATTERED LATE AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS THROUGH THE SHORT TERM. ALTHOUGH...THE GFS AND HRRR MODELS INDICATE A DISTURBANCE RIDING DOWN THE NORTHEAST PERIPHERY OF THE UPPER RIDGE MAY SPARK A FEW STORMS OVER NORTHEAST GA LATER TODAY. HOWEVER... EXPECT THE GREATER THUNDERSTORM THREAT TO BE GENERALLY ALONG AND SOUTH OF A ROME TO ATLANTA TO DUBLIN LINE WHERE THE STRONGER MOISTURE CONVERGENCE AND SEA BREEZE FRONT COULD PROVIDE SUFFICIENT LIFT TO BREAK THE MID LEVEL CAP. ANY DEVELOPMENT WILL LIKELY BE LATE IN THE AFTERNOON...AS WAS SEEN ON SUNDAY... AND WITH CAPE VALUES IN THE 2000-2500 J/KG RANGE... A FEW STORMS COULD BECOME STRONG. THE MAIN THREATS FROM THE STRONGER STORMS WILL BE FREQUENT LIGHTNING AND WIND GUSTS TO 50 MPH THAT COULD KNOCK DOWN A FEW TREES. ALTHOUGH THE DRIER AIR MASS WILL ENHANCE THE WIND GUST THREAT... IT SHOULD LESSON THE FLASH FLOOD THREAT. ISOLATED STORMS MAY LINGER THROUGH THE EVENING... BUT CONVECTIVE ACTIVITY SHOULD DISSIPATE BY MIDNIGHT OR SHORTLY AFTER. AS FOR TEMPS... HAVE LEANED TOWARD THE WARMER GUIDANCE FOR HIGHS AND TOOK A MAV AND MET BLEND FOR LOWS THROUGH THE SHORT TERM. 39 .LONG TERM /WEDNESDAY THROUGH SUNDAY/... HIGH PRESSURE RIDGE OVER THE AREA WILL CONTINUE TO DOMINATE THE WEATHER PATTERN INTO THE LONG TERM. A DECENT AMOUNT OF MOISTURE REMAINS OVER THE AREA AS THE RIDGE KEEP THE STATE IN MOIST W TO SW FLOW THROUGH DAY 6-7. ALL IN ALL WILL CONTINUE WITH A PERSISTENCE FORECAST OF DIURNALLY DRIVEN THUNDERSTORMS THROUGH THE END OF THE FORECAST PERIOD. THE GFS MODEL IS SHOWING A COLD FRONT MOVING INTO THE AREA SAT PULLING IN DRIER AIR BEHIND IT FOR NEXT WEEKEND. THIS IS THE FIRST RUN THIS IS SHOWING UP IN SO NOT VERY CONFIDENT IN THIS HAPPENING RIGHT NOW. WILL CONTINUE WITH PERSISTENCE BUT DEFINITELY KEEP AN EYE ON HOW THIS PROGRESSES OVER THE NEXT FEW DAYS. PRECIPITABLE WATER VALUES STILL SHOWING NEAR 1.5 TO 2.0 INCH SO HEAVY RAIN WITH LOCALIZED FLOODING WILL STILL BE A CONCERN...AT LEAST THROUGH WED/THU. 01 && .AVIATION... 06Z UPDATE... NO MAJOR CHANGES AS VFR CONDITIONS WILL PREVAIL UNDER HIGH PRESSURE INFLUENCE. PATCHY FOG WILL DEVELOP AGAIN EARLY THIS MORNING... BUT QUICKLY DISSIPATE AROUND SUNRISE. EXPECT FEW-SCT CU TO DEVELOP BY 17-19Z. ISOLATED TO LOW SCATTERED CONVECTION STILL ANTICIPATED DURING THE LATE AFTERNOON/EARLY EVENING HOURS... SO CONTINUED TO SHOW PROB30 22-24Z AT ALL TAF SITES FOR NOW. NEARLY CALM WINDS THIS MORNING... WILL START OUT WSW BY 12Z... THEN BACK MORE SSW BY THE AFTERNOON AND INTO THE EVENING. SPEEDS GENERALLY LESS THAN 10 KTS. //ATL CONFIDENCE...06Z UPDATE... HIGH ON ALL ELEMENTS. 39 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 94 72 96 73 / 20 20 30 20 ATLANTA 95 74 95 76 / 30 30 30 20 BLAIRSVILLE 89 68 91 69 / 20 20 30 20 CARTERSVILLE 94 69 95 71 / 30 30 30 20 COLUMBUS 95 73 95 75 / 30 30 30 30 GAINESVILLE 93 73 94 75 / 30 20 30 20 MACON 95 72 95 73 / 30 30 30 20 ROME 95 70 97 72 / 30 30 30 20 PEACHTREE CITY 94 69 94 71 / 30 30 30 20 VIDALIA 96 75 96 77 / 30 30 20 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...39 LONG TERM....01 AVIATION...39
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
524 PM CDT MON JUL 23 2012 .DISCUSSION... 342 PM CDT MAIN CONCERNS AND QUESTIONS REVOLVE AROUND CHANCES FOR SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON INTO THE EVENING...OVERNIGHT...AS WELL AS OVER THE NEXT SEVERAL DAYS WITH SEVERE WEATHER AND HEAVY RAINFALL A CONCERN FOR EACH TIME FRAME. IN THE NEAR TERM...SCATTERED MID AND HIGH LEVEL CLOUD COVER CONTINUE TO SPILL SOUTHEAST ACROSS MUCH OF THE CWA. ALTHOUGH THERE HAVE BEEN SOME BREAKS OBSERVED TODAY...THE MAJORITY OF THE DAY HAS OBSERVED PARTLY CLOUDY TO PARTLY SUNNY SKIES. THIS CLOUD COVER HAS LIMITED OVERALL TEMPS TODAY WITH MOST AREAS NOT QUITE RISING AS HIGH AS PREVIOUSLY ANTICIPATED. WITH THE BREAKS...IT DIDNT TAKE MUCH FOR SURFACE TEMPS TO RISE INTO THE MID 90S WITH SOME ISOLATED UPPER 90S. THIS GENERAL TREND HAS BEEN GOOD WITH REGARD TO THE HEAT AND HUMIDITY WHICH WAS EXPECTED TODAY...AS DEWPOINTS DID NOT QUITE MIX OUT WITH MANY LOCATIONS ACROSS NORTHERN ILLINOIS CURRENTLY OBSERVING LOW TO MID 70 DEWPOINTS. AREAS MAY OBSERVE TEMPS RISE A COUPLE OF DEGREES OVER THE NEXT COUPLE OF HOURS...BEFORE THICKER CLOUD COVER UPSTREAM ACROSS SOUTHWEST WISCONSIN MOVES SOUTHEAST ACROSS THE CWA AND STIFLES ANY FURTHER HEATING. WITH SEVERAL RIPPLES IN THE FLOW ALOFT SHIFTING OVERHEAD TODAY...SCATTERED LIGHT SHOWERS HAVE BEEN OBSERVED ACROSS THE SOUTHWEST PORTION OF THE CWA TODAY WITH SOME ISOLATED LIGHTNING STRIKES OBSERVED. WITH A DECENT CAP IN PLACE AND CLOUD COVER HELPING TO LIMIT LOW AND MID LEVEL LAPSE RATES...CONVECTION HAS BEEN KEPT IN CHECK TODAY. ALTHOUGH...CONCERNS AND QUESTIONS STILL REMAIN FOR LATE THIS AFTERNOON INTO THE EVENING. HAVE BEEN MONITORING A STRONGER MID LEVEL FEATURE DROPPING SOUTHEAST ACROSS SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN WITH LATEST RADAR IMAGERY SHOWING SOME RETURNS/SHOWERS MOVING INTO EASTERN IOWA. MY CONCERNS WITH THESE SHOWERS ARE THAT UPSCALE GROWTH COULD OCCUR AS THEY ENCOUNTER A DESTABILIZING ATMOSPHERE OVER NORTHERN ILLINOIS. LATEST RUC ANALYSIS IS INDICATING THAT THE ATMOSPHERE IS DESTABILIZING WITH CIN ERODING AND LOW LEVEL LAPSE RATES STEEPENING. ALTHOUGH THIS IS PROBABLY OCCURRING...I WONDER IF THIS LATEST ANALYSIS MIGHT BE OVERDONE. WHERE FAIRLY STEEP LAPSE RATES OVERLAP THIS MID LEVEL WAVE/SHOWERS...LIGHTNING AND UPSCALE GROWTH HAS BEEN NONEXISTENT. ALSO...AS MID AND HIGH LEVEL CLOUD COVER CONTINUE TO MOVE OVERHEAD...NOT ANTICIPATING ANY REAL GOOD DESTABILIZATION TO CONTINUE ACROSS THE AREA WITH WARM AIR ALOFT REMAINING. SO DESPITE MY CONCERNS...A BETTER SOLUTION FOR THE NEAR TERM INTO THE EVENING ARE THAT SHOWERS MOVE INTO NORTHERN ILLINOIS WITH SOME FURTHER DEVELOPMENT AND ISOLATED STRONGER DEVELOPMENT...BUT WITH THE PREVIOUSLY MENTIONED LIMITING FACTORS HELPING TO ONCE AGAIN KEEP THE CONVECTION AND ANY SEVERE POTENTIAL IN CHECK. CONCERNS THEN SHIFT TOWARDS LATE TONIGHT INTO EARLY TUESDAY MORNING. ANOTHER STRONGER AND MORE DEFINED MID LEVEL WAVE NOTED ON LATEST WATER VAPOR IMAGERY ACROSS THE DAKOTAS WILL DROP SOUTHEAST ACROSS THE REGION. THIS WAVE WILL ENCOUNTER A STRENGTHENING LOW LEVEL JET ADVECTING A VERY MOIST AIR MASS INTO IT AND OVER A LOW LEVEL BAROCLINIC ZONE DROPPING SOUTH THROUGH THE CWA...WITH DEVELOPMENT EXPECTED ACROSS CENTRAL WISCONSIN. THIS WAVE/FORCING AND STEERING FLOW WILL SHIFT THIS CLUSTER OF SHOWERS/THUNDERSTORMS SOUTHEAST ACROSS NORTHERN ILLINOIS AND NORTHWEST INDIANA...WITH THE BEST CHANCES EXPECTED NORTH OF LINE FROM DIXON IN ILLINOIS TO FOWLER IN INDIANA AND THE BEST CHANCES WITH REGARDS TO TIMING EXPECTED TO BE AFTER MIDNIGHT. AS THIS COMPLEX MOVES ACROSS THE AREA IT WILL ENCOUNTER A VERY MOIST AND UNSTABLE ATMOSPHERE WITH HIGH DEWPOINT/PWAT AIR IN PLACE. CONCERNS DURING THIS TIME FRAME WOULD BE FOR SOME ISOLATED LARGE HAIL...BUT WITH CONCERNS MORE TOWARD THE HEAVY RAIN POTENTIAL. ALTHOUGH THIS DOES NOT APPEAR TO BE A CLASSIC HEAVY RAIN SETUP...MANY FEATURES ARE IN PLACE TO PROVIDE SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS THAT WILL ALL HAVE THE POTENTIAL TO PRODUCE HEAVY DOWNPOURS...INCLUDING LOW LEVEL FLOW BRIEFLY ORIENTING ITSELF WITH REGARD TO THE BAROCLINIC ZONE SUCH TO BRING AT LEAST SOME PERIOD OF POTENTIAL TRAINING OF CELLS. WILL CONTINUE TO MAKE MENTION OF THESE THREATS IN THE HWO AS WELL AS AN ESF. RODRIGUEZ THURSDAY THROUGH MONDAY...MEDIUM RANGE GUIDANCE IS IN PRETTY DECENT AGREEMENT WITH THE MAIN FEATURES INTO EARLY NEXT WEEK. SURFACE LOW PRESSURE WILL BE EXITING OFF TO THE EAST THURSDAY MORNING WITH ITS TRAILING COLD FRONT SOMEWHERE NEAR THE AREA. GUIDANCE DOES DIFFER ON HOW QUICKLY THE FRONT MOVES ACROSS THE AREA THURSDAY. WILL KEEP POPS IN WITH THE BEST CHANCE DURING THE MORNING BUT IT IS POSSIBLE THE FRONT COULD BE EXITING BY THAT TIME. BEYOND THAT...A CLOSED UPPER LOW CURRENTLY SPINNING OVER SOUTHERN BRITISH COLUMBIA WILL SLOWLY MOVE EASTWARD INTO UPPER RIDGING OVER SASKATCHEWAN. BY THURSDAY MORNING...THE LOW WILL BE IN THE VICINITY OF NORTHWEST MN/NORTHEAST NORTH DAKOTA HEADING SOUTHEAST BRINGING A SURFACE LOW WITH IT. THIS WILL BEGIN TO AFFECT THE AREA LATER THURSDAY NIGHT OR FRIDAY MORNING WITH ANOTHER COOL FRONT DROPPING ACROSS THE AREA. AN UPPER TROUGH AXIS LOOKS TO LAG THIS SYSTEM SO AT LEAST LOW PRECIP CHANCES WILL LINGER INTO FRIDAY. SURFACE HIGH PRESSURE THEN ARRIVES INTO SATURDAY MORNING AS UPPER RIDGING BECOMES RE-ESTABLISHED ACROSS THE WESTERN U.S. A TROUGH MOVES THROUGH THE RIDGE SPAWNING SURFACE LOW DEVELOPMENT ACROSS THE HIGH PLAINS LATER SATURDAY AND SPREADING WARM ADVECTION EASTWARD ACROSS THE LOCAL AREA FOLLOWED BY THE PASSAGE OF ANOTHER SURFACE LOW INTO MONDAY. THIS WHOLE SYSTEM RESULTS IN CHANCES FOR SHOWERS AND STORMS FROM LATE SUNDAY ON. TEMPS LOOK TO REMAIN MORE IN CHECK GIVEN PERIODIC CHANCES FOR PRECIP...GENERALLY LOWER HEIGHTS OVER THE AREA AND OCCASIONAL FRONTAL PASSAGES. DEPENDING ON FRONTAL TIMING THURSDAY...SOUTHERN AREAS MAY REACH THE 90S...BUT OTHER THAN THAT WILL KEEP HIGHS IN THE MID TO UPPER 80S FOR NOW. MDB && .CLIMATE... 400 AM CDT RECORDS HIGHS FOR TODAY JULY 23RD ARE: CHICAGO 99 /1914/ ROCKFORD 104 /1934/ RECORD WARM LOWS FOR TODAY JULY 23RD ARE: CHICAGO 78 /1965/ ROCKFORD 76 /1965/ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * WEST-SOUTHWEST WINDS AROUND 10 KT OCCASIONALLY GUSTING TO THE MIDDLE TEENS THROUGH THE REMAINDER OF THE AFTERNOON...WITH A WIND SHIFT TO NORTHWEST THEN NORTHEAST OVERNIGHT. * SHRA/TSRA POTENTIAL THIS EVENING AND OVERNIGHT. * POTENTIAL FOR CEILINGS TO LOWER TO MVFR LEVELS TONIGHT. RC //DISCUSSION...UPDATED 22Z... SHRA IN WISCONSIN ASSOCIATED WITH MIDLEVEL WAVE ARE REALLY STRUGGLING AGAINST VERY WARM TEMPERATURES ALOFT...DESPITE GOOD INSTABILITY AND WIND SHEAR. THERE HASNT BEEN MUCH EVIDENCE OF COOLING CLOUD TOPS ON IR SATELLITE IMAGERY AND NO LIGHTNING STRIKES WITH THE ACTIVITY. WITH THIS IN MIND...PULLED PREVAILING TSRA OUT THIS EVENING FROM THE TAFS IN THE 22Z UPDATE AND WENT WITH -SHRA AND VCTS. HAVE A LOWER CONFIDENCE IN TSRA ACTUALLY OCCURRING BUT WITH THE GOOD INSTABILITY IN PLACE...CANNOT COMPLETELY RULE IT OUT. THERE MAY BE A BETTER CHANCE FOR TSRA OVERNIGHT WITH ANOTHER MIDLEVEL WAVE DROPPING SOUTHWARD...AS WELL AS A SURFACE FRONTAL BOUNDARY. FROM 18Z... A COLD FRONT IS EXPECTED TO SAG SOUTH INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT AND BECOME NEARLY STATIONARY BEFORE STARTING TO MOVE BACK TO THE NORTH ON TUESDAY. THIS WILL PROVIDE A PROLONGED FOCUS FOR SHOWERS/THUNDERSTORMS TO DEVELOP AND TRAIN ACROSS THE AREA. ONE UPPER LEVEL TROUGH WILL MOVE INTO THE AREA THIS EVENING AND MAY START THE CONVECTIVE ACTIVITY EARLY. BETTER CHANCES FOR SHOWERS/THUNDERSTORMS LATER IN THE OVERNIGHT HOURS AS A SECOND UPPER LEVEL TROUGH MOVES ACROSS THE AREA. MODEL GUIDANCE CONTINUES TO SHOW CEILING HEIGHTS AT VFR LEVELS. BUT WITH A FRONT IN THE AREA AND A PROLONGED PERIOD OF PRECIPITATION THE CEILINGS COULD COME DOWN AT LEAST INTO THE MVFR RANGE. PAW //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH CONFIDENCE IN WIND TRENDS INTO EARLY EVENING...LOW CONFIDENCE IN TIMING OF WIND SHIFT WITH FRONT LATE EVENING AND OVERNIGHT. * MEDIUM CONFIDENCE IN SHRA IMPACTING TERMINALS THIS EVENING...LOW CONFIDENCE IN ANY TSRA IMPACTING TERMINALS. LOW CONFIDENCE IN SHRA/TSRA TRENDS OVERNIGHT. * LOW CONFIDENCE IN MVFR CIGS OVERNIGHT. RC //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH FRIDAY...PERIODIC CHANCES FOR TSRA...ELSE VFR. SATURDAY...VFR. SUNDAY...CHANCE TSRA. BMD && .MARINE... 300 PM CDT RATHER ACTIVE FORECAST PERIOD LIES AHEAD WITH THE FIRST OF SEVERAL LOWS AND FRONTS AFFECTING THE LAKE THIS AFTERNOON. SURFACE LOW PRESSURE HAS MOVES INTO CENTRAL QUEBEC AND WILL LIFT NORTHEASTWARD WHILE DEEPENING AS IT REACHES NEWFOUNDLAND TUESDAY MORNING/EARLY AFTERNOON. THE COLD FRONT ASSOCIATED WITH THIS LOW IS MAKING SOUTHEASTWARD PROGRESS AND RUNS FROM NEAR THE STRAITS OF MACKINAC SOUTHEASTWARD TO NEAR MANITOWOC AT 2 PM CDT. WINDS WILL TURN NORTHERLY AS THE FRONT PASSES THROUGH THE EVENING. IT APPEARS THAT THERE MAY BE A BRIEF PERIOD OF STRONGER WINDS FROM NEAR THE MANITOU ISLANDS NORTHWARD TO THE STRAITS EARLY THIS EVENING BEHIND THE FRONT WITH 25 KT GUSTS POSSIBLE BEFORE SETTLING DOWN. A SIMILAR INCREASE IN SPEEDS MAY OCCUR EARLY TONIGHT ACROSS THE SOUTHERN PART OF THE LAKE BEHIND THE FRONT. HIGH PRESSURE WILL APPROACH TUESDAY ALLOWING WINDS TO DIMINISH WITH A NORTHEASTERLY DIRECTION IN PLACE. ATTENTION THEN TURNS TO LOW PRESSURE DEVELOPING ACROSS THE CENTRAL/NORTHERN PLAINS INTO WEDNESDAY. THIS LOW LOOKS TO REACH THE LAKE WEDNESDAY EVENING BUT THE STRENGTH IS SOMEWHAT IN QUESTION. SOME MODEL GUIDANCE CONTINUES TO REALLY DEEPEN IN AS IT CROSSES THE LAKE BUT THIS STILL LOOKS OVERDONE. DO EXPECT A LOW WITH A PRESSURE OF AROUND 29.5 INCHES...THOUGH IT COULD BE STRONGER...TO CROSS THE CENTRAL PART OF THE LAKE. SOUTH WINDS WILL INCREASE AHEAD OF THE LOW ACROSS THE SOUTHERN HALF OF THE LAKE WEDNESDAY MORNING WHILE EAST OR NORTHEAST WINDS WILL OCCUR NORTH. DEPENDING ON THE STRENGTH OF THE LOW WIND SPEEDS MAY NEED TO BE INCREASED OVER CURRENT FORECAST VALUES. SHOULD A MUCH DEEPER SCENARIO PAN OUT...WHICH AGAIN LOOKS TO BE A RATHER LOW PROBABILITY...THEN GALES COULD DEVELOP. THE LOW THEN CLEARS TO THE EAST THURSDAY MORNING LEAVING A WEAK PRESSURE GRADIENT BEHIND IT BUT AHEAD OF A WEAKER LOW WHICH WILL CROSS THE LAKE FRIDAY MORNING. HIGH PRESSURE WILL GRADUALLY BUILD ON SATURDAY. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
346 PM CDT MON JUL 23 2012 .DISCUSSION... 342 PM CDT MAIN CONCERNS AND QUESTIONS REVOLVE AROUND CHANCES FOR SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON INTO THE EVENING...OVERNIGHT...AS WELL AS OVER THE NEXT SEVERAL DAYS WITH SEVERE WEATHER AND HEAVY RAINFALL A CONCERN FOR EACH TIME FRAME. IN THE NEAR TERM...SCATTERED MID AND HIGH LEVEL CLOUD COVER CONTINUE TO SPILL SOUTHEAST ACROSS MUCH OF THE CWA. ALTHOUGH THERE HAVE BEEN SOME BREAKS OBSERVED TODAY...THE MAJORITY OF THE DAY HAS OBSERVED PARTLY CLOUDY TO PARTLY SUNNY SKIES. THIS CLOUD COVER HAS LIMITED OVERALL TEMPS TODAY WITH MOST AREAS NOT QUITE RISING AS HIGH AS PREVIOUSLY ANTICIPATED. WITH THE BREAKS...IT DIDNT TAKE MUCH FOR SURFACE TEMPS TO RISE INTO THE MID 90S WITH SOME ISOLATED UPPER 90S. THIS GENERAL TREND HAS BEEN GOOD WITH REGARD TO THE HEAT AND HUMIDITY WHICH WAS EXPECTED TODAY...AS DEWPOINTS DID NOT QUITE MIX OUT WITH MANY LOCATIONS ACROSS NORTHERN ILLINOIS CURRENTLY OBSERVING LOW TO MID 70 DEWPOINTS. AREAS MAY OBSERVE TEMPS RISE A COUPLE OF DEGREES OVER THE NEXT COUPLE OF HOURS...BEFORE THICKER CLOUD COVER UPSTREAM ACROSS SOUTHWEST WISCONSIN MOVES SOUTHEAST ACROSS THE CWA AND STIFLES ANY FURTHER HEATING. WITH SEVERAL RIPPLES IN THE FLOW ALOFT SHIFTING OVERHEAD TODAY...SCATTERED LIGHT SHOWERS HAVE BEEN OBSERVED ACROSS THE SOUTHWEST PORTION OF THE CWA TODAY WITH SOME ISOLATED LIGHTNING STRIKES OBSERVED. WITH A DECENT CAP IN PLACE AND CLOUD COVER HELPING TO LIMIT LOW AND MID LEVEL LAPSE RATES...CONVECTION HAS BEEN KEPT IN CHECK TODAY. ALTHOUGH...CONCERNS AND QUESTIONS STILL REMAIN FOR LATE THIS AFTERNOON INTO THE EVENING. HAVE BEEN MONITORING A STRONGER MID LEVEL FEATURE DROPPING SOUTHEAST ACROSS SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN WITH LATEST RADAR IMAGERY SHOWING SOME RETURNS/SHOWERS MOVING INTO EASTERN IOWA. MY CONCERNS WITH THESE SHOWERS ARE THAT UPSCALE GROWTH COULD OCCUR AS THEY ENCOUNTER A DESTABILIZING ATMOSPHERE OVER NORTHERN ILLINOIS. LATEST RUC ANALYSIS IS INDICATING THAT THE ATMOSPHERE IS DESTABILIZING WITH CIN ERODING AND LOW LEVEL LAPSE RATES STEEPENING. ALTHOUGH THIS IS PROBABLY OCCURRING...I WONDER IF THIS LATEST ANALYSIS MIGHT BE OVERDONE. WHERE FAIRLY STEEP LAPSE RATES OVERLAP THIS MID LEVEL WAVE/SHOWERS...LIGHTNING AND UPSCALE GROWTH HAS BEEN NONEXISTENT. ALSO...AS MID AND HIGH LEVEL CLOUD COVER CONTINUE TO MOVE OVERHEAD...NOT ANTICIPATING ANY REAL GOOD DESTABILIZATION TO CONTINUE ACROSS THE AREA WITH WARM AIR ALOFT REMAINING. SO DESPITE MY CONCERNS...A BETTER SOLUTION FOR THE NEAR TERM INTO THE EVENING ARE THAT SHOWERS MOVE INTO NORTHERN ILLINOIS WITH SOME FURTHER DEVELOPMENT AND ISOLATED STRONGER DEVELOPMENT...BUT WITH THE PREVIOUSLY MENTIONED LIMITING FACTORS HELPING TO ONCE AGAIN KEEP THE CONVECTION AND ANY SEVERE POTENTIAL IN CHECK. CONCERNS THEN SHIFT TOWARDS LATE TONIGHT INTO EARLY TUESDAY MORNING. ANOTHER STRONGER AND MORE DEFINED MID LEVEL WAVE NOTED ON LATEST WATER VAPOR IMAGERY ACROSS THE DAKOTAS WILL DROP SOUTHEAST ACROSS THE REGION. THIS WAVE WILL ENCOUNTER A STRENGTHENING LOW LEVEL JET ADVECTING A VERY MOIST AIR MASS INTO IT AND OVER A LOW LEVEL BAROCLINIC ZONE DROPPING SOUTH THROUGH THE CWA...WITH DEVELOPMENT EXPECTED ACROSS CENTRAL WISCONSIN. THIS WAVE/FORCING AND STEERING FLOW WILL SHIFT THIS CLUSTER OF SHOWERS/THUNDERSTORMS SOUTHEAST ACROSS NORTHERN ILLINOIS AND NORTHWEST INDIANA...WITH THE BEST CHANCES EXPECTED NORTH OF LINE FROM DIXON IN ILLINOIS TO FOWLWER IN INDIANA AND THE BEST CHANCES WITH REGARDS TO TIMING EXPECTED TO BE AFTER MIDNIGHT. AS THIS COMPLEX MOVES ACROSS THE AREA IT WILL ENCOUNTER A VERY MOIST AND UNSTABLE ATMOSPHERE WITH HIGH DEWPOINT/PWAT AIR IN PLACE. CONCERNS DURING THIS TIME FRAME WOULD BE FOR SOME ISOLATED LARGE HAIL...BUT WITH CONCERNS MORE TOWARD THE HEAVY RAIN POTENTIAL. ALTHOUGH THIS DOES NOT APPEAR TO BE A CLASSIC HEAVY RAIN SETUP...MANY FEATURES ARE IN PLACE TO PROVIDE SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS THAT WILL ALL HAVE THE POTENTIAL TO PRODUCE HEAVY DOWNPOURS...INCLUDING LOW LEVEL FLOW BRIEFLY ORIENTING ITSELF WITH REGARD TO THE BAROCLINIC ZONE SUCH TO BRING AT LEAST SOME PERIOD OF POTENTIAL TRAINING OF CELLS. WILL CONTINUE TO MAKE MENTION OF THESE THREATS IN THE HWO AS WELL AS AN ESF. RODRIGUEZ THURSDAY THROUGH MONDAY...MEDIUM RANGE GUIDANCE IS IN PRETTY DECENT AGREEMENT WITH THE MAIN FEATURES INTO EARLY NEXT WEEK. SURFACE LOW PRESSURE WILL BE EXITING OFF TO THE EAST THURSDAY MORNING WITH ITS TRAILING COLD FRONT SOMEWHERE NEAR THE AREA. GUIDANCE DOES DIFFER ON HOW QUICKLY THE FRONT MOVES ACROSS THE AREA THURSDAY. WILL KEEP POPS IN WITH THE BEST CHANCE DURING THE MORNING BUT IT IS POSSIBLE THE FRONT COULD BE EXITING BY THAT TIME. BEYOND THAT...A CLOSED UPPER LOW CURRENTLY SPINNING OVER SOUTHERN BRITISH COLUMBIA WILL SLOWLY MOVE EASTWARD INTO UPPER RIDGING OVER SASKATCHEWAN. BY THURSDAY MORNING...THE LOW WILL BE IN THE VICINITY OF NORTHWEST MN/NORTHEAST NORTH DAKOTA HEADING SOUTHEAST BRINGING A SURFACE LOW WITH IT. THIS WILL BEGIN TO AFFECT THE AREA LATER THURSDAY NIGHT OR FRIDAY MORNING WITH ANOTHER COOL FRONT DROPPING ACROSS THE AREA. AN UPPER TROUGH AXIS LOOKS TO LAG THIS SYSTEM SO AT LEAST LOW PRECIP CHANCES WILL LINGER INTO FRIDAY. SURFACE HIGH PRESSURE THEN ARRIVES INTO SATURDAY MORNING AS UPPER RIDGING BECOMES RE-ESTABLISHED ACROSS THE WESTERN U.S. A TROUGH MOVES THROUGH THE RIDGE SPAWNING SURFACE LOW DEVELOPMENT ACROSS THE HIGH PLAINS LATER SATURDAY AND SPREADING WARM ADVECTION EASTWARD ACROSS THE LOCAL AREA FOLLOWED BY THE PASSAGE OF ANOTHER SURFACE LOW INTO MONDAY. THIS WHOLE SYSTEM RESULTS IN CHANCES FOR SHOWERS AND STORMS FROM LATE SUNDAY ON. TEMPS LOOK TO REMAIN MORE IN CHECK GIVEN PERIODIC CHANCES FOR PRECIP...GENERALLY LOWER HEIGHTS OVER THE AREA AND OCCASIONAL FRONTAL PASSAGES. DEPENDING ON FRONTAL TIMING THURSDAY...SOUTHERN AREAS MAY REACH THE 90S...BUT OTHER THAN THAT WILL KEEP HIGHS IN THE MID TO UPPER 80S FOR NOW. MDB && .CLIMATE... 400 AM CDT RECORDS HIGHS FOR TODAY JULY 23RD ARE: CHICAGO 99 /1914/ ROCKFORD 104 /1934/ RECORD WARM LOWS FOR TODAY JULY 23RD ARE: CHICAGO 78 /1965/ ROCKFORD 76 /1965/ && .HYDROLOGY... 400 AM CDT THERE IS A MODEST SETUP FOR LOCALIZED HEAVY RAIN IN THE REGION OF NORTHERN IL/NORTHWEST IN/SOUTHERN WI TONIGHT INTO EARLY TUESDAY MORNING. ANOMALOUS DEEP LAYER MOISTURE VALUES NEAR THE 90TH PERCENTILE FOR JULY ARE FORECAST OVER THE AREA TONIGHT WITH FAVORABLE PARAMETERS FOR ROBUST STORM DEVELOPMENT DUE TO TALL AND FAIRLY DEEP INSTABILITY. PARAMETERS FOR REGENERATION AND STORM TRAINING ARE ALSO IN PLACE DUE TO A SLOW-MOVING FRONT ORIENTED FROM WEST TO EAST. THE MID EVENING INTO OVERNIGHT IS ALSO A FAVORED TIME PERIOD FOR HEAVY RAINFALL BASED ON CLIMATOLOGY. FOR RAINFALL AMOUNTS FROM THIS EVENING THROUGH TUESDAY MORNING...THERE IS LIKELY TO BE A SWATH OF RAINFALL IN EXCESS OF AN INCH WITHIN THE NORTHERN IL/NORTHWEST IN/SOUTHERN WI AREA AND HOW WIDE THAT IS REMAINS UNCERTAIN AT THIS TIME. THIS IS MOST FAVORED NEAR THE IL/WI STATE LINE /ALSO FAVORED BY THE CIPS ANALOGS/. LOCALIZED AMOUNTS AROUND OR IN EXCESS OF TWO INCHES ARE POSSIBLE GIVEN THE MOISTURE PARAMETERS. FLASH FLOOD GUIDANCE VALUES ARE GENERALLY HIGH WITH THE PERSISTENT DRYNESS...HOWEVER THE MOST FAVORED AREA FOR RAINFALL TONIGHT INCLUDES URBAN AREAS OF ROCKFORD AND CHICAGOLAND WHERE POTENTIAL FOR ANY HEAVY RAINFALL TO BECOME EXCESSIVE IS MUCH GREATER. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WEST-SOUTHWEST WINDS OCCASIONALLY GUSTING TO THE MIDDLE TEENS THROUGH THE REMAINDER OF THE AFTERNOON. * POTENTIAL FOR SHOWERS/THUNDERSTORMS TO DEVELOP THIS EVENING...AND TO CONTINUE OVER THE AREA THROUGH THE OVERNIGHT HOURS. * POTENTIAL FOR CEILINGS TO LOWER TO MVFR LEVELS TONIGHT. * WIND DIRECTION WITH THE FRONT IN THE AREA OVERNIGHT INTO TUESDAY. PAW //DISCUSSION...UPDATED 18Z... A COLD FRONT IS EXPECTED TO SAG SOUTH INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT AND BECOME NEARLY STATIONARY BEFORE STARTING TO MOVE BACK TO THE NORTH ON TUESDAY. THIS WILL PROVIDE A PROLONGED FOCUS FOR SHOWERS/THUNDERSTORMS TO DEVELOP AND TRAIN ACROSS THE AREA. ONE UPPER LEVEL TROUGH WILL MOVE INTO THE AREA THIS EVENING AND MAY START THE CONVECTIVE ACTIVITY EARLY. BETTER CHANCES FOR SHOWERS/THUNDERSTORMS LATER IN THE OVERNIGHT HOURS AS A SECOND UPPER LEVEL TROUGH MOVES ACROSS THE AREA. MODEL GUIDANCE CONTINUES TO SHOW CEILING HEIGHTS AT VFR LEVELS. BUT WITH A FRONT IN THE AREA AND A PROLONGED PERIOD OF PRECIPITATION THE CEILINGS COULD COME DOWN AT LEAST INTO THE MVFR RANGE. PAW //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND DIRECTION/SPEED FOR THE REST OF THE AFTERNOON AND EVENING. LOW CONFIDENCE OVERNIGHT INTO TUESDAY. * MEDIUM CONFIDENCE IN SHOWERS/THUNDERSTORMS DEVELOPING THIS EVENING...LOW CONFIDENCE IN TIMING AND DURATION. * LOW CONFIDENCE IN PREVAILING MVFR CEILINGS OVERNIGHT. PAW //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT THROUGH FRIDAY...PERIODIC CHANCES FOR TSRA...ELSE VFR. SATURDAY...VFR. SUNDAY...CHANCE TSRA. BMD && .MARINE... 300 PM CDT RATHER ACTIVE FORECAST PERIOD LIES AHEAD WITH THE FIRST OF SEVERAL LOWS AND FRONTS AFFECTING THE LAKE THIS AFTERNOON. SURFACE LOW PRESSURE HAS MOVES INTO CENTRAL QUEBEC AND WILL LIFT NORTHEASTWARD WHILE DEEPENING AS IT REACHES NEWFOUNDLAND TUESDAY MORNING/EARLY AFTERNOON. THE COLD FRONT ASSOCIATED WITH THIS LOW IS MAKING SOUTHEASTWARD PROGRESS AND RUNS FROM NEAR THE STRAITS OF MACKINAC SOUTHEASTWARD TO NEAR MANITOWOC AT 2 PM CDT. WINDS WILL TURN NORTHERLY AS THE FRONT PASSES THROUGH THE EVENING. IT APPEARS THAT THERE MAY BE A BRIEF PERIOD OF STRONGER WINDS FROM NEAR THE MANITOU ISLANDS NORTHWARD TO THE STRAITS EARLY THIS EVENING BEHIND THE FRONT WITH 25 KT GUSTS POSSIBLE BEFORE SETTLING DOWN. A SIMILAR INCREASE IN SPEEDS MAY OCCUR EARLY TONIGHT ACROSS THE SOUTHERN PART OF THE LAKE BEHIND THE FRONT. HIGH PRESSURE WILL APPROACH TUESDAY ALLOWING WINDS TO DIMINISH WITH A NORTHEASTERLY DIRECTION IN PLACE. ATTENTION THEN TURNS TO LOW PRESSURE DEVELOPING ACROSS THE CENTRAL/NORTHERN PLAINS INTO WEDNESDAY. THIS LOW LOOKS TO REACH THE LAKE WEDNESDAY EVENING BUT THE STRENGTH IS SOMEWHAT IN QUESTION. SOME MODEL GUIDANCE CONTINUES TO REALLY DEEPEN IN AS IT CROSSES THE LAKE BUT THIS STILL LOOKS OVERDONE. DO EXPECT A LOW WITH A PRESSURE OF AROUND 29.5 INCHES...THOUGH IT COULD BE STRONGER...TO CROSS THE CENTRAL PART OF THE LAKE. SOUTH WINDS WILL INCREASE AHEAD OF THE LOW ACROSS THE SOUTHERN HALF OF THE LAKE WEDNESDAY MORNING WHILE EAST OR NORTHEAST WINDS WILL OCCUR NORTH. DEPENDING ON THE STRENGTH OF THE LOW WIND SPEEDS MAY NEED TO BE INCREASED OVER CURRENT FORECAST VALUES. SHOULD A MUCH DEEPER SCENARIO PAN OUT...WHICH AGAIN LOOKS TO BE A RATHER LOW PROBABILITY...THEN GALES COULD DEVELOP. THE LOW THEN CLEARS TO THE EAST THURSDAY MORNING LEAVING A WEAK PRESSURE GRADIENT BEHIND IT BUT AHEAD OF A WEAKER LOW WHICH WILL CROSS THE LAKE FRIDAY MORNING. HIGH PRESSURE WILL GRADUALLY BUILD ON SATURDAY. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
130 AM EDT MON JUL 23 2012 .AVIATION / 06Z TAF ISSUANCE / ... CONTINUE WITH VFR THROUGH THE PERIOD. KIWX AND KLOT RADARS SHOWING LIGHT SHOWERS BUT AREA OBS INDICATING HIGH BASE IN NATURE AND NO CIG OR VSBY ISSUES. WILL THEREFORE STAY WITH JUST VCSH AT BOTH SITES TO ACCOUNT FOR THIS. && .PREV DISCUSSION... /ISSUED 326 PM EDT SUN JUL 22 2012/ SHORT TERM... /TONIGHT THROUGH MONDAY NIGHT. MID LEVEL CLOUD COVER MOVING INTO FORECAST AREA FROM REMNANTS OF UPSTREAM OVERNIGHT CONVECTION. FEW LIGHT SHOWERS/SPRINKLES REMAIN BUT NO SIGNS OF ORGANIZATION WITH MODERATELY CAPPED...SLIGHTLY UNSTABLE ATMOSPHERE AHEAD OF IT. SOMEWHAT DIFFUSE COLD FRONT WAS LOCATED FROM CENTRAL MINNESOTA TO NORTHERN MICHIGAN. SERIES OF DISTURBANCES WILL TOP THE RIDGE...ALLOWING FOR HEIGHTS TO FLATTEN SOMEWHAT...ALLOWING MORE OF AN AREA OF CONVERGENCE VS A FRONT TO DROP SOUTH WITH TIME. HI RES MODELS ALL AGREE ON CONVECTION BREAKING OUT SOMEWHERE FROM CNTRL MN INTO WISCONSIN. CORFIDI VECTOR SUGGEST THIS WOULD TREND ESE WITH TIME...POSSIBLY IMPACTING PORTIONS OF THE ARE TONIGHT. LL JET WILL FOCUS INITIALLY TO THE NW OF THE REGION AND BECOME WESTERLY WITH TIME. INCREASING ISENTROPIC LIFT NOTED IN NAM/LOCAL WRF AFTER MIDNIGHT WITH STRONG SIGNALS FOR CONVECTION TO OVERSPREAD MUCH OF THE AREA. 12Z 4KM SPC WRF DEVELOPS CONVECTION ACROSS WISCONSIN LATER THIS EVENING AND TRACKS IT ACROSS SOUTHERN LWR MI INTO FAR N INDIANA. 16Z HRRR ALSO DEVELOPS CONVECTION ACROSS WESTERN WISCONSIN THIS EVENING...TRACKING SE TOWARDS THE AREA AFTER 6Z. WITH ALL THE SCENARIOS IN PLAY...CONFIDENCE LOW TO MODERATE IN CONVECTION AFFECTING OUR AREA. HAVE DECIDED TO INCREASE POPS CLOSER TO IN/MI STATE LINE INTO THE 30 TO 40 PERCENT RANGE WHERE GREATEST CHANCE FOR CONVECTION WILL LIE. WITH LINGERING CLOUD COVER AND INCREASING LL MSTR AND TEMPS...OVERNIGHT LOWS WILL BE A FEW DEGREES WARMER THAN LAST NIGHT. IN THE 70 TO 75 DEGREE RANGE. FORECAST LEFT GENERALLY UNTOUCHED MON/MOM NGT WITH IMPACTS OF OVERNIGHT CONVECTION TO BE KEY IN ADDITIONAL CONVECTIVE CHANCES THROUGH THE REMAINDER OF THE PERIOD AND CLOUD COVER TO RAISE POTENTIAL HAVOC WITH TEMPS. MODELS WOULD SUGGEST THAT THERE SHOULD BE AT LEAST A PERIOD OF PARTIAL CLEARING LATE MORNING INTO EARLY AFTERNOON THAT WOULD BE MORE THAN SUFFICIENT TO ALLOW FOR A 10 TO 20 DEGREE JUMP IN TEMPS DURING PEAK HEATING. SERIES OF WAVES WILL CONTINUE WITH ADDITIONAL STORMS POSSIBLE MONDAY AFTERNOON AND NIGHT WITH INCREASING INSTABILITY. HAVE LEFT LOW TO MID RANGE CHC POPS AS IT AND HIGHS IN THE MID 90S. IF MORE IN THE WAY OF SUNSHINE IS SEEN...GIVEN THE WARM START TO THE DAY...TEMPS IN THE UPPER 90S WOULD BE POSSIBLE. ON THE FLIP SIDE...CLOUD COVER COULD KEEP US CONFINED IN THE 80S. LONG TERM... DIFFICULT PD COMING UP W/AS YET SIG UNCERTAINTY CONCERNING IMPULSE LADEN PERTURBED FLW EXTNDG W-E ALG THE US/CANADIAN BORDER. HWVR MED RANGE CONSENSUS MAINTAINS THE NOTION OF CNTRL US RIDGE FLATTENING BY MID WEEK W/EPISODIC CONVN XPCD. THE DEVIL LIES IN THE DETAILS AND SPECIFICALLY TIMING AND EWD EJECTION OF SIG SW TROUGH SITTING OF VANCOUVER THIS AFTN OVRTOP PLAINS RIDGE THROUGH MIDWEEK BUT CONSIDERABLE LG SCALE AGREEMENT EXISTS W/12Z GUIDANCE. MESOSCALE DISPLACEMENTS OF NEAR STATIONARY FNTL THROUGH THE GREAT LAKES/OH VALLEY LIKELY OWING TO XPCD UPSTREAM DVLPMNT OF CONV COMPLEXES STEERING ESE OVR THE UPR RIDGE TUE-WED AND INVOF OF UPR TROUGH ACRS THE WRN LAKES THU-THU NIGHT. WHILE NOT ENTHUSED W/4 DAY WINDOW OF POPS CAN NOT ARGUE AT HOLDING W/AT LEAST A LOWER BOUND CHC MENTION EITHER AND WILL GENERALLY HOLD CLOSE W/PRIOR GUIDANCE. OTHERWISE TEMPS INHERENTLY TRICKY PER PROXIMAL THERMAL RIDGE POSITION W/BOUTS OF INTENSE LL WAA LIKELY. ALLBLEND GUIDANCE NUMBERS ACCEPTED W/NOTED SW-NE ORIENTED GRADIENT XPCD ACRS THE FNTL ZONE BUT AGAIN POTENTIALLY COLDER/WARMER PENDING EXACT PLACEMENT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...FISHER LONG TERM...T AVIATION...JAL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
344 PM CDT MON JUL 23 2012 .SHORT TERM /TONIGHT/... MAIN FORECAST CONCERN IS POTENTIAL FOR CONVECTION ACROSS NORTHERN IOWA TONIGHT. WEAK BOUNDARY EXTENDS ACROSS SOUTHERN MN COMBINED WITH AN 500MB VORT MAX WILL BE THE FOCUS FOR THUNDERSTORMS LATER THIS EVENING INTO TUESDAY MORNING. NAM/SREF/RAP KEEP CONVECTION ALONG THE BORDER OVERNIGHT...4.0KM WRF FROM NCEP HAS SOME ISOLATED CONVECTION ACROSS THE NORTHERN TWO TIERS OF COUNTIES AND THE NSSL 4.0KM WRF IS SIMILAR. LATEST HRRR (17Z RUN) IS MORE BULLISH IN BREAKING OUT CONVECTION THIS AFTERNOON INTO THE EVENING AND SEEMS MORE WIDESPREAD THAN ANY OTHER MODEL. LEANED TOWARD A BLEND OF THE NAM12/SREF WITH TIMING AND PLACEMENT OF CONVECTION OVER NORTHERN IOWA PAST 03Z TUESDAY. WITH THE VERY DRY AIR MASS IN THE LOWER LEVELS AND BUFR SOUNDINGS INDICATIVE OF MAINLY WIND THREAT AS THEY MIX UP TO AROUND 850-700MB DEPENDING ON WHICH MODEL...CANNOT RULE AN ISOLATED SEVERE POTENTIAL TONIGHT ACROSS NORTHERN IOWA. EFFECTIVE SHEAR AROUND 35-40KTS BUT THERE IS LITTLE...IF ANY...LOW LEVEL SHEAR WITH 0-1KM AND 0-3KM SHEAR LESS THAN 15KTS AND 30KTS RESPECTIVELY. THERE IS PLENTY OF INSTABILITY PRESENT BUT WITH SUCH A STRONG CAP IN PLACE...IT WILL TAKE SOME TIME FOR IT ERODE. WITH THE UPPER LEVEL VORT MAX TIMING TO MOVE INTO NORTHERN IOWA AFTER 03Z...HAVE HIGHEST POPS B/T 06-12Z TUESDAY. .LONG TERM /TUESDAY THROUGH MONDAY/... THERE IS LITTLE CHANGE NEEDED TO THE GOING FORECAST. IT WILL REMAIN HOT THROUGH WEDNESDAY WITH CHANCES FOR SHOWERS/THUNDERSTORMS ACROSS THE NORTHEAST AND EAST. SOUNDING ARE SHOWING SOME DRY AIR ALOFT AND A CLASSIC INVERTED V SO THERE IS SOME POTENTIAL FOR STRONG/DAMAGING WIND WITH THESE STORMS AND THAT IS COVERED IN VARIOUS OUTLOOKS. THE MODELS ARE A LITTLE SLOWER IN BRINGING THE FRONT THROUGH SO WEDNESDAY HIGHS MAY NEED TO BE BROUGHT UP BUT I WOULD LIKE TO SEE WHAT CLOUDS/CONVECTIVE TRENDS WILL DO BEFORE RAISING THEM MORE THAN I HAVE DONE. SOMETHING ELSE OF NOTE THAT MAY BE A CAVEAT TO THE SEVERE POTENTIAL IS THAT THE MODELS HAD BEEN ADVERTISING A VORT MAX TO DROP DOWN THE RIDGE ACROSS THE EAT/NORTHEAST AND NOW THEY ARE TAKING THAT VORT MAX EAST AND NOT DROPPING IT SOUTH. QPF IS ALSO LESS NOW FOR THE AREA WHICH IS NOT A SURPRISE REALLY. OTHER THINGS OF NOTE IS THAT A SHORTWAVE THAT WAS PROGGED FOR SATURDAY NIGHT IS NOW COMING THROUGH ON SUNDAY. THIS IS ADVERTISED BY BOTH THE GFS AND EURO SO I LEFT SATURDAY DRY AND INCREASED POPS ON SUNDAY. TEMPS WILL STILL BE SEASONAL BUT COMPARED TO WHAT WE HAVE THE TERM "COOLER" CAN BE APPLIED HERE AND IT WILL IN DEED FEEL THAT WAY. HIGHS FOR THE WEEKEND WILL BE IN THE LOWER TO MID 80S WITH MAYBE SOME 90S ACROSS THE FAR SOUTHWEST. THE COOLER TEMPS DO NOT APPEAR TO BE STAYING AS WAS ELUDED TO YESTERDAY...THE MODELS REBUILD THE RIDGE OVER THE ROCKIES AND TRENDS ARE TO BRING THE UPPER RIDGE BACK INTO THE MIDWEST. THIS WILL OCCUR BEYOND THE EXTENDED PERIOD SO JUST HOW MUCH HEAT WE WILL SEE IS STILL GOING TO NEED TO BE EVALUATED. WE WILL AT LEAST SEE A SEVERAL DAY BREAK FROM THE OPPRESSIVE HEAT LATER THIS WEEK. && .AVIATION...23/18Z EXPECTING VFR CONDITIONS THROUGHOUT THE TAF FORECAST PERIOD EVEN WITH THE SURFACE BOUNDARY DRAPED ALONG THE IA/MN BORDER. A FEW ISOLATED TSTM ARE POSSIBLE LATE THIS AFTERNOON...BUT LOW CONFIDENCE IN DECIPHERING THE TIMING AND LOCATION OF CONVECTION. IT MAY STAY TO THE NORTH OF MCW/ALO IF CONVECTION DOES BREAK. OTHERWISE...WINDS MIX DOWN THIS AFTERNOON AND AGAIN TOMORROW WITH SOME GUSTS TO AROUND 15KTS POSSIBLE. && .DMX WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 7 PM CDT WEDNESDAY ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE- CRAWFORD-DALLAS-DAVIS-DECATUR-GREENE-GUTHRIE-HAMILTON-JASPER-LUCAS- MADISON-MAHASKA-MARION-MONROE-POLK-RINGGOLD-SAC-STORY-TAYLOR-UNION- WAPELLO-WARREN-WAYNE-WEBSTER. && $$ LONG TERM...FAB SHORT TERM...PODRAZIK AVIATION...PODRAZIK
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
950 PM EDT TUE JUL 24 2012 .UPDATE... ISSUED AT 950 PM EDT TUE JUL 24 2012 UPDATED THE FORECAST TO DROP THE SOUTHERN WATCH BOX AND EFFECTIVELY REMOVE POPS FOR MOST OF THE NIGHT DOWN THERE. OTHERWISE...ADJUSTED THE SKY COVER...TEMPS...AND DEWPOINTS FOR CURRENT OBS AND TRENDS. THE ONLY FLY IN THE OINTMENT FOR A QUIET REST OF THE NIGHT WILL BE THE SEVERE THUNDERSTORM HEADING EAST...JUST NORTH OF INTERSTATE 64...ACROSS CENTRAL KENTUCKY. SHOULD THIS...AND ANY OF ITS TRAILING CONVECTION TO THE WEST...HOLD TOGETHER...DESPITE LOWER INSTABILITY AND A MORE WORKED OVER ENVIRONMENT HERE IN THE EAST...IT COULD MAKE IT INTO THE CWA AROUND MIDNIGHT. FOR NOW HAVE PAINTED IT AS DISSIPATING ON OUR FRINGES...BUT IT HAS BEEN GOING STRONG FOR OVER AN HOUR NOW. WILL RE-EXAMINE IN AN HOUR OR SO...SHOULD IT STILL BE INTACT. UPDATES HAVE BEEN ISSUED TO THE ZONES...NDFD GRIDS...AND WEB. UPDATE ISSUED AT 815 PM EDT TUE JUL 24 2012 UPDATED THE GRIDS TO REFLECT THE DIMINISHING THREAT OF SEVERE WEATHER OR ANY FURTHER CONVECTION IN OUR FAR SOUTHERN COUNTIES. HOWEVER... WILL HOLD OFF ON DROPPING THE BOX FOR ANOTHER HALF HOUR OR SO JUST TO BE SURE THAT SOME BOUNDARY FROM THE WEST DOESN/T KICK OFF ANY STORMS ALONG OUR BORDER REGION. THE BULK OF OUR AREA HAS NOW BEEN WORKED OVER AND INSTABILITY IS FALLING SO THE ONLY THREAT ARE REMAINS IN THE FAR SOUTHWEST. HOWEVER...WOULD NOT RULE OUT SOME REDEVELOPMENT ALONG THE STALLED BOUNDARY LATER TONIGHT OR EVEN A BATCH OF CONVECTION DROPPING DOWN FROM THE NORTH TOWARDS DAWN. HAVE KEPT THESE IDEAS GOING FROM THE PREVIOUS SHIFT. IN ADDITION...PATCHES TO AREAS OF FOG ARE ALSO ANTICIPATED THROUGH MUCH OF THE AREA BY DAWN...BECOMING LOCALLY DENSE. THE FORECAST HAS THIS HANDLED WELL SO NOT ADJUSTMENTS NEEDED HERE. DID ALSO TWEAK SKY COVER...TEMPS AND DEWPOINTS FOR THE CURRENT OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE NDFD GRIDS AND THE WEB. UPDATE ISSUED AT 633 PM EDT TUE JUL 24 2012 WITH A MUGGY AND UNSTABLE AIRMASS STILL IN PLACE ACROSS THE SOUTHWEST ZONES...SPC HAS ISSUED A NEW SEVERE THUNDERSTORM WATCH UNTIL 11 PM. ONLY A FEW STORMS AFFECTING THE AREA PRESENTLY...BUT WE COULD STILL SEE SOME NEW DEVELOPMENT THIS EVENING. MEANWHILE...QUIET CONDITIONS ACROSS A GOOD CHUNK OF EASTERN KENTUCKY WILL LIKELY STAY THAT WAY THROUGH MUCH OF TONIGHT. THUS...POPS HAVE BEEN REMOVED OR LOWERED ACROSS THE BOARD. ALSO...WITH TEMPERATURES ALREADY ON THE COOL SIDE AND RECENT RAINFALL...WE MAY SEE SOME PATCHY FOG OVERNIGHT. ZONE UPDATE IS ALREADY OUT. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 339 PM EDT TUE JUL 24 2012 IMMEDIATE SHORT TERM ISSUES REVOLVE AROUND THE ONGOING WATCH. WITH MORE OF THE ACTIVITY SHIFTING SOUTHWARD...GOING TO CLEAR MORE COUNTIES OUT OF EASTERN KENTUCKY OVER THE NEXT HOUR. MEANWHILE...STILL WATCHING AN OUTFLOW BOUNDARY...FROM CENTRAL ESTILL COUNTY...SOUTHEAST INTO SOUTHERN BREATHITT COUNTY. THIS BOUNDARY COULD TRIGGER ADDITIONAL STORMS AS IT SINKS SOUTHWARD THIS EVENING. THUS...THE WATCH WILL CONTINUE ACROSS OUR SOUTHWEST COUNTIES UNTIL THIS BOUNDARY PUSHES ACROSS THIS AREA. THE HRRR CONTINUES TO SHOW NEW DEVELOPMENT...BUT THUS FAR...HAVE NOT SEEN ANY DEVELOPMENT ALONG THIS BOUNDARY. AS THIS BOUNDARY AND COMPLEX OF STORMS EXITS TO THE SOUTH THIS EVENING...THERE WILL LIKELY BE A TEMPORARY BREAK FROM THE CONVECTION. HOWEVER...ANOTHER WEAK WAVE IS POISED TO DROP SOUTHWARD OVERNIGHT AND COULD GENERATE MORE SHOWERS AND THUNDERSTORMS. WITH LITTLE ACTIVITY UPSTREAM PRESENTLY...OPTING TO KEEP POPS ON THE LOWER SIDE UNTIL BETTER CONFIDENCE CAN BE OBTAINED. A NORTH/SOUTH BOUNDARY WILL THEN SET UP OVER FAR EASTERN KENTUCKY THROUGH TOMORROW AFTERNOON AND EVENING. THIS WILL KEEP UNSETTLED WEATHER IN THE FORECAST THROUGH WEDNESDAY EVENING AS DAYTIME INSTABILITY WILL ONCE AGAIN FUEL STORM DEVELOPMENT...ESPECIALLY OVER SOUTHEAST AND FAR EASTERN KENTUCKY. THE FURTHER WEST YOU GO AWAY FROM THE BOUNDARY...THE MORE LIKELIHOOD TO MISS OUT ON ANY STORMS TOMORROW. BASED ON THE WEAK STORM MOVEMENT TOMORROW AFTERNOON...WE MAY HAVE TO WATCH FOR TRAINING STORMS AND FLASH FLOODING POTENTIAL. PWS WILL STILL BE CLOSE TO 2 INCHES TOMORROW...SO CLEARLY GOING TO HAVE TO KEEP AN EYE ON THE FLOODING POTENTIAL. WE MAY NEED A FLASH FLOOD WATCH...BUT WILL LET THE MIDNIGHT SHIFT REEVALUATE. THIS BOUNDARY WILL EVENTUALLY DEPART TO THE NORTHEAST TOMORROW NIGHT...TAKING THE THREAT OF PRECIPITATION WITH IT AND PUTTING THE AREA UNDER STRONGER INFLUENCE OF THE HIGH. MILD CONDITIONS WILL CONTINUE WITH HIGHS ON WEDNESDAY WELL INTO THE 80S...AND LOWS TONIGHT AND WEDNESDAY NIGHT IN THE LOWER 70S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 339 PM EDT TUE JUL 24 2012 THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN. THURSDAY STARTS OUT WITH A UPPER LOW OVER MINNESOTA WITH A TROUGH EXTENDING SOUTH ALONG THE I35 CORRIDOR. THE TROUGH WILL MOVE TO THE EAST AND WILL PASS EASTERN KENTUCKY ON FRIDAY NIGHT/SATURDAY MORNING TIME FRAME. THE TROUGH WILL FINALLY PUSH A LINGERING COLD FRONT SOUTH AND EAST OF THE AREA ON FRIDAY. THIS WILL HELP TO BRING SOME COOLER AND DRIER AIR INTO THE AREA. WITH THE MODELS IN SUCH GOOD AGREEMENT...RELIED VERY HEAVILY ON THE MODEL BLEND FOR ALL FIELDS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 815 PM EDT TUE JUL 24 2012 THE BULK OF THE CONVECTION HAS NOW FADED THROUGH THE AREA AND SHOULD NOT BE A FACTOR IN THE TAFS THROUGH THE REMAINDER OF THE NIGHT. HOWEVER...PATCHY DENSE FOG WILL BE A THREAT TONIGHT...ESPECIALLY IN VALLEY LOCATIONS. LEFT FOG IN FOR THE TAF STATIONS...THOUGH IT WILL LIKELY BE DEPENDENT ON WHICH AIRPORTS SAW PCPN AT OR NEAR THAT PARTICULAR LOCATION. FOR WEDNESDAY...SCATTERED STORMS ARE AGAIN ANTICIPATED TO DEVELOP BY MID AFTERNOON...MAINLY OVER FAR EASTERN KENTUCKY. HAVE ADDED A VCTS FOR THIS AT JKL BUT LEFT LOZ AND SME CLEAN. WINDS WILL BE LIGHT AND VARIABLE FOR THE MOST PART THROUGH THE TAF PERIOD WITH SOME BREEZES UP TOWARD 5 AND 10 KTS POSSIBLE... GENERALLY FROM THE SOUTHWEST...AROUND PEAK HEATING WEDNESDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...KAS LONG TERM....JJ AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
815 PM EDT TUE JUL 24 2012 .UPDATE... ISSUED AT 815 PM EDT TUE JUL 24 2012 UPDATED THE GRIDS TO REFLECT THE DIMINISHING THREAT OF SEVERE WEATHER OR ANY FURTHER CONVECTION IN OUR FAR SOUTHERN COUNTIES. HOWEVER... WILL HOLD OFF ON DROPPING THE BOX FOR ANOTHER HALF HOUR OR SO JUST TO BE SURE THAT SOME BOUNDARY FROM THE WEST DOESN/T KICK OFF ANY STORMS ALONG OUR BORDER REGION. THE BULK OF OUR AREA HAS NOW BEEN WORKED OVER AND INSTABILITY IS FALLING SO THE ONLY THREAT ARE REMAINS IN THE FAR SOUTHWEST. HOWEVER...WOULD NOT RULE OUT SOME REDEVELOPMENT ALONG THE STALLED BOUNDARY LATER TONIGHT OR EVEN A BATCH OF CONVECTION DROPPING DOWN FROM THE NORTH TOWARDS DAWN. HAVE KEPT THESE IDEAS GOING FROM THE PREVIOUS SHIFT. IN ADDITION...PATCHES TO AREAS OF FOG ARE ALSO ANTICIPATED THROUGH MUCH OF THE AREA BY DAWN...BECOMING LOCALLY DENSE. THE FORECAST HAS THIS HANDLED WELL SO NOT ADJUSTMENTS NEEDED HERE. DID ALSO TWEAK SKY COVER...TEMPS AND DEWPOINTS FOR THE CURRENT OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE NDFD GRIDS AND THE WEB. UPDATE ISSUED AT 633 PM EDT TUE JUL 24 2012 WITH A MUGGY AND UNSTABLE AIRMASS STILL IN PLACE ACROSS THE SOUTHWEST ZONES...SPC HAS ISSUED A NEW SEVERE THUNDERSTORM WATCH UNTIL 11 PM. ONLY A FEW STORMS AFFECTING THE AREA PRESENTLY...BUT WE COULD STILL SEE SOME NEW DEVELOPMENT THIS EVENING. MEANWHILE...QUIET CONDITIONS ACROSS A GOOD CHUNK OF EASTERN KENTUCKY WILL LIKELY STAY THAT WAY THROUGH MUCH OF TONIGHT. THUS...POPS HAVE BEEN REMOVED OR LOWERED ACROSS THE BOARD. ALSO...WITH TEMPERATURES ALREADY ON THE COOL SIDE AND RECENT RAINFALL...WE MAY SEE SOME PATCHY FOG OVERNIGHT. ZONE UPDATE IS ALREADY OUT. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 339 PM EDT TUE JUL 24 2012 IMMEDIATE SHORT TERM ISSUES REVOLVE AROUND THE ONGOING WATCH. WITH MORE OF THE ACTIVITY SHIFTING SOUTHWARD...GOING TO CLEAR MORE COUNTIES OUT OF EASTERN KENTUCKY OVER THE NEXT HOUR. MEANWHILE...STILL WATCHING AN OUTFLOW BOUNDARY...FROM CENTRAL ESTILL COUNTY...SOUTHEAST INTO SOUTHERN BREATHITT COUNTY. THIS BOUNDARY COULD TRIGGER ADDITIONAL STORMS AS IT SINKS SOUTHWARD THIS EVENING. THUS...THE WATCH WILL CONTINUE ACROSS OUR SOUTHWEST COUNTIES UNTIL THIS BOUNDARY PUSHES ACROSS THIS AREA. THE HRRR CONTINUES TO SHOW NEW DEVELOPMENT...BUT THUS FAR...HAVE NOT SEEN ANY DEVELOPMENT ALONG THIS BOUNDARY. AS THIS BOUNDARY AND COMPLEX OF STORMS EXITS TO THE SOUTH THIS EVENING...THERE WILL LIKELY BE A TEMPORARY BREAK FROM THE CONVECTION. HOWEVER...ANOTHER WEAK WAVE IS POISED TO DROP SOUTHWARD OVERNIGHT AND COULD GENERATE MORE SHOWERS AND THUNDERSTORMS. WITH LITTLE ACTIVITY UPSTREAM PRESENTLY...OPTING TO KEEP POPS ON THE LOWER SIDE UNTIL BETTER CONFIDENCE CAN BE OBTAINED. A NORTH/SOUTH BOUNDARY WILL THEN SET UP OVER FAR EASTERN KENTUCKY THROUGH TOMORROW AFTERNOON AND EVENING. THIS WILL KEEP UNSETTLED WEATHER IN THE FORECAST THROUGH WEDNESDAY EVENING AS DAYTIME INSTABILITY WILL ONCE AGAIN FUEL STORM DEVELOPMENT...ESPECIALLY OVER SOUTHEAST AND FAR EASTERN KENTUCKY. THE FURTHER WEST YOU GO AWAY FROM THE BOUNDARY...THE MORE LIKELIHOOD TO MISS OUT ON ANY STORMS TOMORROW. BASED ON THE WEAK STORM MOVEMENT TOMORROW AFTERNOON...WE MAY HAVE TO WATCH FOR TRAINING STORMS AND FLASH FLOODING POTENTIAL. PWS WILL STILL BE CLOSE TO 2 INCHES TOMORROW...SO CLEARLY GOING TO HAVE TO KEEP AN EYE ON THE FLOODING POTENTIAL. WE MAY NEED A FLASH FLOOD WATCH...BUT WILL LET THE MIDNIGHT SHIFT REEVALUATE. THIS BOUNDARY WILL EVENTUALLY DEPART TO THE NORTHEAST TOMORROW NIGHT...TAKING THE THREAT OF PRECIPITATION WITH IT AND PUTTING THE AREA UNDER STRONGER INFLUENCE OF THE HIGH. MILD CONDITIONS WILL CONTINUE WITH HIGHS ON WEDNESDAY WELL INTO THE 80S...AND LOWS TONIGHT AND WEDNESDAY NIGHT IN THE LOWER 70S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 339 PM EDT TUE JUL 24 2012 THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN. THURSDAY STARTS OUT WITH A UPPER LOW OVER MINNESOTA WITH A TROUGH EXTENDING SOUTH ALONG THE I35 CORRIDOR. THE TROUGH WILL MOVE TO THE EAST AND WILL PASS EASTERN KENTUCKY ON FRIDAY NIGHT/SATURDAY MORNING TIME FRAME. THE TROUGH WILL FINALLY PUSH A LINGERING COLD FRONT SOUTH AND EAST OF THE AREA ON FRIDAY. THIS WILL HELP TO BRING SOME COOLER AND DRIER AIR INTO THE AREA. WITH THE MODELS IN SUCH GOOD AGREEMENT...RELIED VERY HEAVILY ON THE MODEL BLEND FOR ALL FIELDS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 815 PM EDT TUE JUL 24 2012 THE BULK OF THE CONVECTION HAS NOW FADED THROUGH THE AREA AND SHOULD NOT BE A FACTOR IN THE TAFS THROUGH THE REMAINDER OF THE NIGHT. HOWEVER...PATCHY DENSE FOG WILL BE A THREAT TONIGHT...ESPECIALLY IN VALLEY LOCATIONS. LEFT FOG IN FOR THE TAF STATIONS...THOUGH IT WILL LIKELY BE DEPENDENT ON WHICH AIRPORTS SAW PCPN AT OR NEAR THAT PARTICULAR LOCATION. FOR WEDNESDAY...SCATTERED STORMS ARE AGAIN ANTICIPATED TO DEVELOP BY MID AFTERNOON...MAINLY OVER FAR EASTERN KENTUCKY. HAVE ADDED A VCTS FOR THIS AT JKL BUT LEFT LOZ AND SME CLEAN. WINDS WILL BE LIGHT AND VARIABLE FOR THE MOST PART THROUGH THE TAF PERIOD WITH SOME BREEZES UP TOWARD 5 AND 10 KTS POSSIBLE... GENERALLY FROM THE SOUTHWEST...AROUND PEAK HEATING WEDNESDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...KAS LONG TERM....JJ AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
545 PM EDT MON JUL 23 2012 .UPDATE... ISSUED AT 545 PM EDT MON JUL 23 2012 DID A QUICK UPDATE TO THE GRIDS AND WEB FORECAST TO ACCOUNT FOR CONVECTIVE TRENDS...OR LACK THERE OF...INTO THE EVENING. ALSO UPDATED THE SKY...TEMPERATURE AND DEWPOINT GRIDS FOR THEIR CURRENT OBSERVATIONS AND TRENDS. UPDATES SENT TO THE WEB AND NDFD...THE ZONES ARE STILL FINE. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 313 PM EDT MON JUL 23 2012 HIGH PRESSURE RIDGE CONTINUES TO DOMINATE TO OUR WEST AND SOUTH...WITH EASTERN KENTUCKY SITTING ON THE PERIPHERALS. THIS MEANS...OUR AREA REMAINS A FOCUS OF CONCERN FOR REPEATED CHANCES FOR SHOWERS AND THUNDERSTORMS OVER THE NEXT 24 TO 48 HOURS. A FEW ISOLATED SHOWERS HANGING ON NEAR THE VIRGINIA BORDER THIS AFTERNOON...BUT THESE SHOULD EXIT INTO VIRGINIA IN THE NEXT HOUR OR SO. A LULL IS EXPECTED INTO THIS EVENING. HOWEVER...A SHORTWAVE TROUGH IS PUSHING INTO SOUTHERN OHIO AND INDIANA. PRESENTLY...NOT MUCH ACTIVITY ASSOCIATED WITH THIS FEATURE. IN FACT...THE SHOWER ACTIVITY EARLIER HAS ALMOST COMPLETELY DRIED UP. STILL SOME QUESTION ON HOW MUCH DEVELOPMENT WILL OCCUR AS THIS TROUGH AXIS PUSHES SOUTH INTO A MORE UNSTABLE AIRMASS. IT IS POSSIBLE WE COULD SEE A FEW ISOLATED SUPERCELLS CAPABLE OF DAMAGING WINDS THROUGH 9 OR 10 PM. THE HRRR HAS HELD CONSISTENT WITH THE IDEA OF ISOLATED SUPERCELLS DEVELOPING AFTER 8 PM...AND TRACKING INTO AREAS NORTH OF I-64 AROUND 9 OR 10 PM. THERE IS SOME WEAK DIRECTIONAL SHEAR TO SUPPORT THIS IDEA. THUS...PLAN TO INCLUDE A SLIGHT CHANCE OF SHOWERS AND STORMS THROUGH LATE EVENING. THIS ACTIVITY WILL GRADUALLY WEAKEN AS IT PUSHES FURTHER SOUTH...SO THE SECOND HALF OF THE NIGHT SHOULD BE MAINLY DRY. MOVING ON TO TOMORROW...IT LOOKS LIKE ANOTHER DECENT WAVE WILL DROP SOUTHEAST FROM MIDDAY INTO THE EVENING HOURS...PRODUCING AN EVEN BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. WIND SHEAR WILL BE EVEN BETTER TOMORROW WITH 700MB WINDS AROUND 30 KNOTS AND 500MB WINDS 35 KNOTS. THERE IS SOME DIRECTIONAL SHEAR AS WELL. THUS...SEVERE THREAT LOOKS PRETTY GOOD TOMORROW FOR SOME DAMAGING WINDS. THE BIGGER CONCERN COULD BE SOME LOCALLY HEAVY RAIN WITH PW VALUES AROUND 2 INCHES AND FREEZING LEVELS OVER 15KFT. ANY STORMS THAT HIT THE SAME AREAS COULD LEAD TO FLASH FLOODING. NOT CONFIDENT ENOUGH TO GO WITH A WATCH...BUT CERTAINLY SOMETHING TO KEEP AN EYE ON. BY TOMORROW NIGHT...THE FIRST ROUND OF CONVECTION WILL DEPART...BUT WE WILL REMAIN IN A FAVORABLE SPOT FOR MORE DEVELOPMENT UPSTREAM...WITH PERHAPS A NOCTURNAL MCS DEVELOPING AND TRACKING INTO OUR AREA. THUS...WILL KEEP SOME CHANCE POPS GOING THROUGH TOMORROW NIGHT. TEMPERATURES WILL REMAIN MILD WITH HIGHS ON TUESDAY CLIMBING TO AROUND 90 AND LOWS TONIGHT AND TOMORROW NIGHT IN THE LOWER 70S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 341 PM EDT MON JUL 23 2012 THE MODELS START OUT IN VERY GOOD AGREEMENT WITH A FAIRLY ZONAL FLOW NORTH OF 40 DEGREES AND UPPER RIDGING DOMINATES SOUTH OF 40 DEGREES. THE SYSTEM TO WATCH IS AN UPPER LOW IN SOUTHWEST MANITOBA WITH A TROUGH EXTENDING INTO THE CENTRAL PLAINS. THIS UPPER LOW STARTS MOVING SLOWLY TO THE EAST SOUTHEAST AND AS IT DOES...IT IS PUSHING THE POLAR FRONT TO THE SOUTH. THE TROUGH CONTINUE PUSHING TO THE ESE AND WILL PUSH A FRONT ACROSS THE COAL FIELDS ON FRIDAY. THIS FRONT WILL STAY JUST SOUTH OF THE AREA AND WILL PUSH BACK INTO THE AREA ON SUNDAY NIGHT. THE DIFFERENCE IN SHORT WAVE TIMING INCREASES WITH TIME...HOWEVER THE GENERAL PATTERN TRANSITION IS IN PRETTY GOOD AGREEMENT. THE SEQUENCING HAS HIGH CONFIDENCE...HOWEVER THE TIMING OF THE SHORT WAVES DECREASES CONFIDENCE IN WITH TIME. FOR TEMPS...NUDGED THE FORECAST TOWARD THE MODEL BLEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 157 PM EDT MON JUL 23 2012 SCATTERED CU HAS ONCE AGAIN DEVELOPED ACROSS THE AREA WITH DAYTIME HEATING. A SHORTWAVE TROUGH COMING IN FROM THE NORTH WILL PRESENT A THREAT FOR A FEW SHOWERS AND THUNDERSTORMS LATER THIS EVENING...BUT CURRENT THINKING IS THE THREAT MAY STAY NORTH OF THE TAF SITES...INCLUDING KJKL. OTHERWISE...CU WILL DISSIPATE THIS EVENING...THEN REDEVELOP AFTER DAYBREAK TOMORROW MORNING. ANOTHER STRONGER DISTURBANCE IS POISED TO DROP IN FROM THE NORTH TOMORROW...PROVIDING A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. ALSO...WITH DEWPOINTS AROUND 70...SOME PATCHY VALLEY FOG WILL BE POSSIBLE AGAIN TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...KAS LONG TERM....JJ AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
342 PM EDT MON JUL 23 2012 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 313 PM EDT MON JUL 23 2012 HIGH PRESSURE RIDGE CONTINUES TO DOMINATE TO OUR WEST AND SOUTH...WITH EASTERN KENTUCKY SITTING ON THE PERIPHERALS. THIS MEANS...OUR AREA REMAINS A FOCUS OF CONCERN FOR REPEATED CHANCES FOR SHOWERS AND THUNDERSTORMS OVER THE NEXT 24 TO 48 HOURS. A FEW ISOLATED SHOWERS HANGING ON NEAR THE VIRGINIA BORDER THIS AFTERNOON...BUT THESE SHOULD EXIT INTO VIRGINIA IN THE NEXT HOUR OR SO. A LULL IS EXPECTED INTO THIS EVENING. HOWEVER...A SHORTWAVE TROUGH IS PUSHING INTO SOUTHERN OHIO AND INDIANA. PRESENTLY...NOT MUCH ACTIVITY ASSOCIATED WITH THIS FEATURE. IN FACT...THE SHOWER ACTIVITY EARLIER HAS ALMOST COMPLETELY DRIED UP. STILL SOME QUESTION ON HOW MUCH DEVELOPMENT WILL OCCUR AS THIS TROUGH AXIS PUSHES SOUTH INTO A MORE UNSTABLE AIRMASS. IT IS POSSIBLE WE COULD SEE A FEW ISOLATED SUPERCELLS CAPABLE OF DAMAGING WINDS THROUGH 9 OR 10 PM. THE HRRR HAS HELD CONSISTENT WITH THE IDEA OF ISOLATED SUPERCELLS DEVELOPING AFTER 8 PM...AND TRACKING INTO AREAS NORTH OF I-64 AROUND 9 OR 10 PM. THERE IS SOME WEAK DIRECTIONAL SHEAR TO SUPPORT THIS IDEA. THUS...PLAN TO INCLUDE A SLIGHT CHANCE OF SHOWERS AND STORMS THROUGH LATE EVENING. THIS ACTIVITY WILL GRADUALLY WEAKEN AS IT PUSHES FURTHER SOUTH...SO THE SECOND HALF OF THE NIGHT SHOULD BE MAINLY DRY. MOVING ON TO TOMORROW...IT LOOKS LIKE ANOTHER DECENT WAVE WILL DROP SOUTHEAST FROM MIDDAY INTO THE EVENING HOURS...PRODUCING AN EVEN BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. WIND SHEAR WILL BE EVEN BETTER TOMORROW WITH 700MB WINDS AROUND 30 KNOTS AND 500MB WINDS 35 KNOTS. THERE IS SOME DIRECTIONAL SHEAR AS WELL. THUS...SEVERE THREAT LOOKS PRETTY GOOD TOMORROW FOR SOME DAMAGING WINDS. THE BIGGER CONCERN COULD BE SOME LOCALLY HEAVY RAIN WITH PW VALUES AROUND 2 INCHES AND FREEZING LEVELS OVER 15KFT. ANY STORMS THAT HIT THE SAME AREAS COULD LEAD TO FLASH FLOODING. NOT CONFIDENT ENOUGH TO GO WITH A WATCH...BUT CERTAINLY SOMETHING TO KEEP AN EYE ON. BY TOMORROW NIGHT...THE FIRST ROUND OF CONVECTION WILL DEPART...BUT WE WILL REMAIN IN A FAVORABLE SPOT FOR MORE DEVELOPMENT UPSTREAM...WITH PERHAPS A NOCTURNAL MCS DEVELOPING AND TRACKING INTO OUR AREA. THUS...WILL KEEP SOME CHANCE POPS GOING THROUGH TOMORROW NIGHT. TEMPERATURES WILL REMAIN MILD WITH HIGHS ON TUESDAY CLIMBING TO AROUND 90 AND LOWS TONIGHT AND TOMORROW NIGHT IN THE LOWER 70S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 341 PM EDT MON JUL 23 2012 THE MODELS START OUT IN VERY GOOD AGREEMENT WITH A FAIRLY ZONAL FLOW NORTH OF 40 DEGREES AND UPPER RIDGING DOMINATES SOUTH OF 40 DEGREES. THE SYSTEM TO WATCH IS AN UPPER LOW IN SOUTHWEST MANITOBA WITH A TROUGH EXTENDING INTO THE CENTRAL PLAINS. THIS UPPER LOW STARTS MOVING SLOWLY TO THE EAST SOUTHEAST AND AS IT DOES...IT IS PUSHING THE POLAR FRONT TO THE SOUTH. THE TROUGH CONTINUE PUSHING TO THE ESE AND WILL PUSH A FRONT ACROSS THE COAL FIELDS ON FRIDAY. THIS FRONT WILL STAY JUST SOUTH OF THE AREA AND WILL PUSH BACK INTO THE AREA ON SUNDAY NIGHT. THE DIFFERENCE IN SHORT WAVE TIMING INCREASES WITH TIME...HOWEVER THE GENERAL PATTERN TRANSITION IS IN PRETTY GOOD AGREEMENT. THE SEQUENCING HAS HIGH CONFIDENCE...HOWEVER THE TIMING OF THE SHORT WAVES DECREASES CONFIDENCE IN WITH TIME. FOR TEMPS...NUDGED THE FORECAST TOWARD THE MODEL BLEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 157 PM EDT MON JUL 23 2012 SCATTERED CU HAS ONCE AGAIN DEVELOPED ACROSS THE AREA WITH DAYTIME HEATING. A SHORTWAVE TROUGH COMING IN FROM THE NORTH WILL PRESENT A THREAT FOR A FEW SHOWERS AND THUNDERSTORMS LATER THIS EVENING...BUT CURRENT THINKING IS THE THREAT MAY STAY NORTH OF THE TAF SITES...INCLUDING KJKL. OTHERWISE...CU WILL DISSIPATE THIS EVENING...THEN REDEVELOP AFTER DAYBREAK TOMORROW MORNING. ANOTHER STRONGER DISTURBANCE IS POISED TO DROP IN FROM THE NORTH TOMORROW...PROVIDING A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. ALSO...WITH DEWPOINTS AROUND 70...SOME PATCHY VALLEY FOG WILL BE POSSIBLE AGAIN TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KAS LONG TERM....JJ AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
313 PM EDT MON JUL 23 2012 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 313 PM EDT MON JUL 23 2012 HIGH PRESSURE RIDGE CONTINUES TO DOMINATE TO OUR WEST AND SOUTH...WITH EASTERN KENTUCKY SITTING ON THE PERIPHERALS. THIS MEANS...OUR AREA REMAINS A FOCUS OF CONCERN FOR REPEATED CHANCES FOR SHOWERS AND THUNDERSTORMS OVER THE NEXT 24 TO 48 HOURS. A FEW ISOLATED SHOWERS HANGING ON NEAR THE VIRGINIA BORDER THIS AFTERNOON...BUT THESE SHOULD EXIT INTO VIRGINIA IN THE NEXT HOUR OR SO. A LULL IS EXPECTED INTO THIS EVENING. HOWEVER...A SHORTWAVE TROUGH IS PUSHING INTO SOUTHERN OHIO AND INDIANA. PRESENTLY...NOT MUCH ACTIVITY ASSOCIATED WITH THIS FEATURE. IN FACT...THE SHOWER ACTIVITY EARLIER HAS ALMOST COMPLETELY DRIED UP. STILL SOME QUESTION ON HOW MUCH DEVELOPMENT WILL OCCUR AS THIS TROUGH AXIS PUSHES SOUTH INTO A MORE UNSTABLE AIRMASS. IT IS POSSIBLE WE COULD SEE A FEW ISOLATED SUPERCELLS CAPABLE OF DAMAGING WINDS THROUGH 9 OR 10 PM. THE HRRR HAS HELD CONSISTENT WITH THE IDEA OF ISOLATED SUPERCELLS DEVELOPING AFTER 8 PM...AND TRACKING INTO AREAS NORTH OF I-64 AROUND 9 OR 10 PM. THERE IS SOME WEAK DIRECTIONAL SHEAR TO SUPPORT THIS IDEA. THUS...PLAN TO INCLUDE A SLIGHT CHANCE OF SHOWERS AND STORMS THROUGH LATE EVENING. THIS ACTIVITY WILL GRADUALLY WEAKEN AS IT PUSHES FURTHER SOUTH...SO THE SECOND HALF OF THE NIGHT SHOULD BE MAINLY DRY. MOVING ON TO TOMORROW...IT LOOKS LIKE ANOTHER DECENT WAVE WILL DROP SOUTHEAST FROM MIDDAY INTO THE EVENING HOURS...PRODUCING AN EVEN BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. WIND SHEAR WILL BE EVEN BETTER TOMORROW WITH 700MB WINDS AROUND 30 KNOTS AND 500MB WINDS 35 KNOTS. THERE IS SOME DIRECTIONAL SHEAR AS WELL. THUS...SEVERE THREAT LOOKS PRETTY GOOD TOMORROW FOR SOME DAMAGING WINDS. THE BIGGER CONCERN COULD BE SOME LOCALLY HEAVY RAIN WITH PW VALUES AROUND 2 INCHES AND FREEZING LEVELS OVER 15KFT. ANY STORMS THAT HIT THE SAME AREAS COULD LEAD TO FLASH FLOODING. NOT CONFIDENT ENOUGH TO GO WITH A WATCH...BUT CERTAINLY SOMETHING TO KEEP AN EYE ON. BY TOMORROW NIGHT...THE FIRST ROUND OF CONVECTION WILL DEPART...BUT WE WILL REMAIN IN A FAVORABLE SPOT FOR MORE DEVELOPMENT UPSTREAM...WITH PERHAPS A NOCTURNAL MCS DEVELOPING AND TRACKING INTO OUR AREA. THUS...WILL KEEP SOME CHANCE POPS GOING THROUGH TOMORROW NIGHT. TEMPERATURES WILL REMAIN MILD WITH HIGHS ON TUESDAY CLIMBING TO AROUND 90 AND LOWS TONIGHT AND TOMORROW NIGHT IN THE LOWER 70S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 313 PM EDT MON JUL 23 2012 LONG TERM DISCUSSION TO FOLLOW SHORTLY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 157 PM EDT MON JUL 23 2012 SCATTERED CU HAS ONCE AGAIN DEVELOPED ACROSS THE AREA WITH DAYTIME HEATING. A SHORTWAVE TROUGH COMING IN FROM THE NORTH WILL PRESENT A THREAT FOR A FEW SHOWERS AND THUNDERSTORMS LATER THIS EVENING...BUT CURRENT THINKING IS THE THREAT MAY STAY NORTH OF THE TAF SITES...INCLUDING KJKL. OTHERWISE...CU WILL DISSIPATE THIS EVENING...THEN REDEVELOP AFTER DAYBREAK TOMORROW MORNING. ANOTHER STRONGER DISTURBANCE IS POISED TO DROP IN FROM THE NORTH TOMORROW...PROVIDING A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. ALSO...WITH DEWPOINTS AROUND 70...SOME PATCHY VALLEY FOG WILL BE POSSIBLE AGAIN TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KAS LONG TERM....JJ AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
158 PM EDT MON JUL 23 2012 .UPDATE... ISSUED AT 158 PM EDT MON JUL 23 2012 ISOLATED SHOWER/THUNDERSTORM ACTIVITY APPEARS TO BE SHIFTING OFF TO THE SOUTH AND EAST. MEANWHILE...SHORTWAVE TROUGH IS DROPPING SOUTH ACROSS INDIANA AND OHIO WITH A BROKEN LINE OF SHOWERS AND ISOLATED THUNDERSTORMS. THIS TROUGH WILL BE MOVING INTO A VERY UNSTABLE AIRMASS AS IT REACHES NORTHERN KENTUCKY. SO THERE IS A THREAT OF SOME RAPID INTENSIFICATION AS THIS AXIS PUSHES SOUTH INTO EASTERN KENTUCKY. THIS WILL OCCUR MORE THIS EVENING AFTER 22 OR 23Z. UNTIL THIS TIME...IT SHOULD REMAIN FAIRLY QUIET AND WARM. THE HRRR ACTUALLY HOLDS OFF ANY ACTIVITY UNTIL 1Z OR 2Z. THUS...IT APPEARS TO BE ARRIVING LATER THAN ORIGINALLY THOUGHT. WE WILL BE LOSING SOME OF THE INSTABILITY WITH TIME...BUT ENOUGH SHOULD LINGER TO STILL POSE A THREAT OF PRECIPITATION. THE SEVERE THREAT LOOKS A LITTLE BETTER WITH SOME WEAK SHEAR PRESENT. THUS...WE WILL NEED TO MONITOR THIS THREAT THROUGH THE EVENING HOURS. UPDATE ISSUED AT 958 AM EDT MON JUL 23 2012 OBSERVING SOME ENHANCED CU ALREADY ACROSS SOUTH CENTRAL KENTUCKY THIS MORNING AND IS DEVELOPING TO THE EAST ACROSS AREAS SOUTH OF THE HAL ROGERS PARKWAY. THIS APPEARS TO BE THE TARGETED AREA OF SHOWERS AND THUNDERSTORMS EARLY TODAY. EVEN SEEING A FEW SHOWERS ALREADY DEVELOPING. THE HRRR SEEMS TO BE HANDLING THIS SITUATION THE BEST...SO HAVE REALLY ADJUSTED POPS TO LINE UP WITH THE HRRR THROUGH EARLY AFTERNOON. THE NEXT CONCERN IS THE WAVE DROPPING IN FROM THE NORTH LATE TODAY. IT APPEARS A LINE OF SHOWERS AND STORMS MAY DEVELOP AND PUSH SOUTH INTO NORTHERN KENTUCKY AFTER 21Z. AS THIS LINE CONTINUES TO SINK SOUTHWARD...IT SHOULD EVENTUALLY WEAKEN AS IT REACHES CENTRAL KENTUCKY AS THE SUN SETS AND IT LOSES ANY REMAINING INSTABILITY. A ROGUE SEVERE STORM CANNOT BE RULED OUT GIVEN THE TREMENDOUS INSTABILITY. HOWEVER...THIS WILL NOT BE A WIDESPREAD SEVERE EVENT BY ANY MEANS. THE MAIN THREAT WITH ANY SEVERE STORM WOULD BE DAMAGING WINDS. UPDATE ISSUED AT 745 AM EDT MON JUL 23 2012 FRESHENED UP THE MORNING HOURLY GRIDS ACCORDING TO THE LATEST OBSERVATIONAL TRENDS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 359 AM EDT MON JUL 23 2012 STRONG UPPER LEVEL RIDGE IS CURRENTLY CENTERED NEAR MISSOURI...WITH A COUPLE OF WEAKER SHORT WAVE TROUGHS RIDING SOUTHEAST ON THE NORTHEASTERN PERIPHERY OF THE RIDGE ACROSS THE OHIO VALLEY. THESE HAVE RESULTED IN MAINLY MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF IN/OH/WV...WITH A FEW LIGHT SHOWERS OCCURRING AS WELL. IN EASTERN KENTUCKY...SOME SCATTERED HIGH BASED CU AS WELL AS MID-LEVEL CLOUD COVER HAS BEEN FORMING DURING THE OVERNIGHT HOURS...WITH MOST TEMPERATURES IN THE LOW 70S. THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM. THE UPPER LEVEL RIDGE AXIS WILL GRADUALLY WEAKENING AND SHIFT SOUTHEAST INTO THE LOWER MISSISSIPPI VALLEY WITH TIME...AS A HUDSON BAY LOW DEEPENS...AND ALLOWS FOR MORE TROUGHINESS ACROSS NEW ENGLAND. WARM AND HUMID CONDITIONS WILL PERSIST ACROSS EASTERN KENTUCKY...WITH ISOLATED TO SCATTERED CONVECTION THREATENING FROM TIME TO TIME. BETTER CHANCES OF CONVECTION WILL GENERALLY EXIST CLOSER TO THE OHIO RIVER...CLOSER TO THE PASSING BOUTS OF FORCING. LESSER CHANCES WILL EXIST TOWARDS THE CUMBERLAND VALLEY. AS FAR AS THE SEVERE THREAT GOES...WHILE AN ISOLATED SEVERE STORM CAN NOT BE COMPLETELY RULED OUT TODAY WITH THE POTENTIAL FOR OUTFLOW BOUNDARY INTERACTION AND STORM MERGERS...TUESDAY LOOKS TO BE A BETTER CHANCE...WITH MORE ORGANIZED CONVECTION LIKELY. A MORE STOUT SHORT WAVE TROUGH LOOKS TO PASS THROUGH DURING THE AFTERNOON...HELPING TO NOSE IN A SURFACE WARM FRONT FROM THE NORTHWEST...ALIGNING CLOSE TO THE OHIO RIVER. GIVEN THE HIGH FREEZING LEVELS...DAMAGING WIND WILL CONTINUE TO BE THE MAIN THREAT. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 425 AM EDT MON JUL 23 2012 MODELS ARE GENERALLY IN GOOD AGREEMENT THROUGH THE PERIOD...WITH SOME TIMING DIFFERENCES LATE IN THE WEEK WITH A SFC COLD FRONT. THESE TIMING DIFFERENCES ARE LIKELY DUE IN LARGE PART TO SOME CONVECTIVE FEEDBACK IN THE 0Z GFS THAT DEEPENS A SFC LOW MOVING ACROSS THE GREAT LAKES AND INTO THE NORTHEAST WITH SFC PRESS SIGNIFICANTLY LOWER THAN THE 0Z ECMWF AND 0Z GFS ENSEMBLE MEAN. THUS THE CONSENSUS DATA LOAD LEANING TOWARD RECENT ECMWF RUNS FEATURING A SFC COLD FRONT ABOUT 12 HRS LATER WAS USED. THE PERIOD WILL START WITH THE REGION IN WEST NORTHWEST TO NORTHWESTERLY FLOW ALOFT BETWEEN RIDGING OVER THE LOWER MS VALLEY AND A TROUGH OVER EASTERN CANADA AND THE NORTHEASTERN STATES. AS THE WEEK PROGRESSES THE RIDGE WILL FLATTEN OUT AND REMAIN CENTERED OVER THE GULF COAST REGION AND SOUTHEAST FROM WED INTO THU...WITH A WINDOW OF SHORTWAVE RIDGING EXTENDING NORTH INTO THE REGION FOR WED AFTERNOON THROUGH AROUND MIDDAY THU...AT WHICH POINT THE FIRST OF A SERIES SHORTWAVE TROUGHS WILL APPROACH THE AREA...CROSSING THE AREA ON FRIDAY WITH ANOTHER ONE AGAIN ON SAT. A SFC BOUNDARY INITIALLY STALLED NEAR THE WV AND KY BORDER SHOULD GRADUALLY LIFT NE AS A WARM FRONT ON WED NIGHT INTO THU...WITH A SFC LOW DEVELOPING ALONG THIS FRONTAL ZONE IN ADVANCE OF A SHORTWAVE. THIS SFC LOW WILL PASS TO OUR N AND NE ACROSS THE GREAT LAKES AND INTO THE NORTHEAST AND PUSH A COLD FRONT INTO THE REGION THU NIGHT...PROBABLY CROSSING THE AREA ON FRI AND THEN WASHING OUT. THE SECOND SHORTWAVE ON SAT SHOULD PUSH ANOTHER SFC BOUNDARY DOWN INTO THE REGION ON SAT INTO SAT NIGHT...LIKELY STALLING AS WELL AND THEN RETURNING NORTHEAST JUST AFTER THE PERIOD AS RIDGING REORGANIZES OVER THE CENTRAL PLAINS ONCE AGAIN. ROUNDS OF CONVECTION...SOME POSSIBLY CAPABLE OF TRAINING AND SOME LOCALIZED HEAVY RAIN MAY BE ONGOING AT THE START OF THE PERIOD IN THE VICINITY OF THE BOUNDARY. THIS SHOULD LEAD TO THE HIGHEST POPS ON TUE NIGHT NEAR THE WV AND KY BORDER. THIS BOUNDARY MAY NOT MOVE MUCH UNTIL LATER ON WED AND AGAIN WILL BE THE FOCUS FOR CONVECTION AS WEAK SHORTWAVES MOVE AROUND THE RIDGE. WITH THE BOUNDARY PUSHING NORTH WED NIGHT INTO THU...THERE MAY BE A LULL IN CONVECTION THOUGH SOMETHING ISOLATED CANNOT BE RULED OUT WITH ACTIVITY POSSIBLY PICKING UP ON THU NIGHT AS THE SHORTWAVE AND COLD FRONT APPROACH. AS ALREADY NOTED OPTED FOR A COLD FRONT PASSING THROUGH ON FRI...LEADING TO HIGHER POPS ON FRI VERSUS THU NIGHT AS SUGGEST BY THE 0Z GFS. SCATTERED STORMS REMAIN POSSIBLE UNTIL THE NEXT BOUNDARY PUSHES INTO THE REGION ON SAT INTO SAT NIGHT. WITH THE BOUNDARY NEARBY...AN ISOLATED STORM OR TWO CANNOT BE RULED OUT ON TEMPERATURES THROUGH THE PERIOD WILL AVERAGE A BIT ABOVE NORMAL...WITH THE GREATEST DEPARTURES IN OVERNIGHT LOWS AS DEWPOINTS IN THE UPPER 60S TO LOWER 70S WILL LIMIT THE DIURNAL RANGES. THE WARMEST DAY IN WHICH HEAT INDICES COULD APPROACH 100 SHOULD BE ON THU...WHEN MAX T SHOULD REACH OR EXCEED 90 IN MOST AREAS OUTSIDE OF THE HIGHEST TERRAIN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 157 PM EDT MON JUL 23 2012 SCATTERED CU HAS ONCE AGAIN DEVELOPED ACROSS THE AREA WITH DAYTIME HEATING. A SHORTWAVE TROUGH COMING IN FROM THE NORTH WILL PRESENT A THREAT FOR A FEW SHOWERS AND THUNDERSTORMS LATER THIS EVENING...BUT CURRENT THINKING IS THE THREAT MAY STAY NORTH OF THE TAF SITES...INCLUDING KJKL. OTHERWISE...CU WILL DISSIPATE THIS EVENING...THEN REDEVELOP AFTER DAYBREAK TOMORROW MORNING. ANOTHER STRONGER DISTURBANCE IS POISED TO DROP IN FROM THE NORTH TOMORROW...PROVIDING A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. ALSO...WITH DEWPOINTS AROUND 70...SOME PATCHY VALLEY FOG WILL BE POSSIBLE AGAIN TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...GEOGERIAN LONG TERM....JP AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
958 AM EDT MON JUL 23 2012 .UPDATE... ISSUED AT 958 AM EDT MON JUL 23 2012 OBSERVING SOME ENHANCED CU ALREADY ACROSS SOUTH CENTRAL KENTUCKY THIS MORNING AND IS DEVELOPING TO THE EAST ACROSS AREAS SOUTH OF THE HAL ROGERS PARKWAY. THIS APPEARS TO BE THE TARGETED AREA OF SHOWERS AND THUNDERSTORMS EARLY TODAY. EVEN SEEING A FEW SHOWERS ALREADY DEVELOPING. THE HRRR SEEMS TO BE HANDLING THIS SITUATION THE BEST...SO HAVE REALLY ADJUSTED POPS TO LINE UP WITH THE HRRR THROUGH EARLY AFTERNOON. THE NEXT CONCERN IS THE WAVE DROPPING IN FROM THE NORTH LATE TODAY. IT APPEARS A LINE OF SHOWERS AND STORMS MAY DEVELOP AND PUSH SOUTH INTO NORTHERN KENTUCKY AFTER 21Z. AS THIS LINE CONTINUES TO SINK SOUTHWARD...IT SHOULD EVENTUALLY WEAKEN AS IT REACHES CENTRAL KENTUCKY AS THE SUN SETS AND IT LOSES ANY REMAINING INSTABILITY. A ROGUE SEVERE STORM CANNOT BE RULED OUT GIVEN THE TREMENDOUS INSTABILITY. HOWEVER...THIS WILL NOT BE A WIDESPREAD SEVERE EVENT BY ANY MEANS. THE MAIN THREAT WITH ANY SEVERE STORM WOULD BE DAMAGING WINDS. UPDATE ISSUED AT 745 AM EDT MON JUL 23 2012 FRESHENED UP THE MORNING HOURLY GRIDS ACCORDING TO THE LATEST OBSERVATIONAL TRENDS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 359 AM EDT MON JUL 23 2012 STRONG UPPER LEVEL RIDGE IS CURRENTLY CENTERED NEAR MISSOURI...WITH A COUPLE OF WEAKER SHORT WAVE TROUGHS RIDING SOUTHEAST ON THE NORTHEASTERN PERIPHERY OF THE RIDGE ACROSS THE OHIO VALLEY. THESE HAVE RESULTED IN MAINLY MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF IN/OH/WV...WITH A FEW LIGHT SHOWERS OCCURRING AS WELL. IN EASTERN KENTUCKY...SOME SCATTERED HIGH BASED CU AS WELL AS MID-LEVEL CLOUD COVER HAS BEEN FORMING DURING THE OVERNIGHT HOURS...WITH MOST TEMPERATURES IN THE LOW 70S. THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM. THE UPPER LEVEL RIDGE AXIS WILL GRADUALLY WEAKENING AND SHIFT SOUTHEAST INTO THE LOWER MISSISSIPPI VALLEY WITH TIME...AS A HUDSON BAY LOW DEEPENS...AND ALLOWS FOR MORE TROUGHINESS ACROSS NEW ENGLAND. WARM AND HUMID CONDITIONS WILL PERSIST ACROSS EASTERN KENTUCKY...WITH ISOLATED TO SCATTERED CONVECTION THREATENING FROM TIME TO TIME. BETTER CHANCES OF CONVECTION WILL GENERALLY EXIST CLOSER TO THE OHIO RIVER...CLOSER TO THE PASSING BOUTS OF FORCING. LESSER CHANCES WILL EXIST TOWARDS THE CUMBERLAND VALLEY. AS FAR AS THE SEVERE THREAT GOES...WHILE AN ISOLATED SEVERE STORM CAN NOT BE COMPLETELY RULED OUT TODAY WITH THE POTENTIAL FOR OUTFLOW BOUNDARY INTERACTION AND STORM MERGERS...TUESDAY LOOKS TO BE A BETTER CHANCE...WITH MORE ORGANIZED CONVECTION LIKELY. A MORE STOUT SHORT WAVE TROUGH LOOKS TO PASS THROUGH DURING THE AFTERNOON...HELPING TO NOSE IN A SURFACE WARM FRONT FROM THE NORTHWEST...ALIGNING CLOSE TO THE OHIO RIVER. GIVEN THE HIGH FREEZING LEVELS...DAMAGING WIND WILL CONTINUE TO BE THE MAIN THREAT. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 425 AM EDT MON JUL 23 2012 MODELS ARE GENERALLY IN GOOD AGREEMENT THROUGH THE PERIOD...WITH SOME TIMING DIFFERENCES LATE IN THE WEEK WITH A SFC COLD FRONT. THESE TIMING DIFFERENCES ARE LIKELY DUE IN LARGE PART TO SOME CONVECTIVE FEEDBACK IN THE 0Z GFS THAT DEEPENS A SFC LOW MOVING ACROSS THE GREAT LAKES AND INTO THE NORTHEAST WITH SFC PRESS SIGNIFICANTLY LOWER THAN THE 0Z ECMWF AND 0Z GFS ENSEMBLE MEAN. THUS THE CONSENSUS DATA LOAD LEANING TOWARD RECENT ECMWF RUNS FEATURING A SFC COLD FRONT ABOUT 12 HRS LATER WAS USED. THE PERIOD WILL START WITH THE REGION IN WEST NORTHWEST TO NORTHWESTERLY FLOW ALOFT BETWEEN RIDGING OVER THE LOWER MS VALLEY AND A TROUGH OVER EASTERN CANADA AND THE NORTHEASTERN STATES. AS THE WEEK PROGRESSES THE RIDGE WILL FLATTEN OUT AND REMAIN CENTERED OVER THE GULF COAST REGION AND SOUTHEAST FROM WED INTO THU...WITH A WINDOW OF SHORTWAVE RIDGING EXTENDING NORTH INTO THE REGION FOR WED AFTERNOON THROUGH AROUND MIDDAY THU...AT WHICH POINT THE FIRST OF A SERIES SHORTWAVE TROUGHS WILL APPROACH THE AREA...CROSSING THE AREA ON FRIDAY WITH ANOTHER ONE AGAIN ON SAT. A SFC BOUNDARY INITIALLY STALLED NEAR THE WV AND KY BORDER SHOULD GRADUALLY LIFT NE AS A WARM FRONT ON WED NIGHT INTO THU...WITH A SFC LOW DEVELOPING ALONG THIS FRONTAL ZONE IN ADVANCE OF A SHORTWAVE. THIS SFC LOW WILL PASS TO OUR N AND NE ACROSS THE GREAT LAKES AND INTO THE NORTHEAST AND PUSH A COLD FRONT INTO THE REGION THU NIGHT...PROBABLY CROSSING THE AREA ON FRI AND THEN WASHING OUT. THE SECOND SHORTWAVE ON SAT SHOULD PUSH ANOTHER SFC BOUNDARY DOWN INTO THE REGION ON SAT INTO SAT NIGHT...LIKELY STALLING AS WELL AND THEN RETURNING NORTHEAST JUST AFTER THE PERIOD AS RIDGING REORGANIZES OVER THE CENTRAL PLAINS ONCE AGAIN. ROUNDS OF CONVECTION...SOME POSSIBLY CAPABLE OF TRAINING AND SOME LOCALIZED HEAVY RAIN MAY BE ONGOING AT THE START OF THE PERIOD IN THE VICINITY OF THE BOUNDARY. THIS SHOULD LEAD TO THE HIGHEST POPS ON TUE NIGHT NEAR THE WV AND KY BORDER. THIS BOUNDARY MAY NOT MOVE MUCH UNTIL LATER ON WED AND AGAIN WILL BE THE FOCUS FOR CONVECTION AS WEAK SHORTWAVES MOVE AROUND THE RIDGE. WITH THE BOUNDARY PUSHING NORTH WED NIGHT INTO THU...THERE MAY BE A LULL IN CONVECTION THOUGH SOMETHING ISOLATED CANNOT BE RULED OUT WITH ACTIVITY POSSIBLY PICKING UP ON THU NIGHT AS THE SHORTWAVE AND COLD FRONT APPROACH. AS ALREADY NOTED OPTED FOR A COLD FRONT PASSING THROUGH ON FRI...LEADING TO HIGHER POPS ON FRI VERSUS THU NIGHT AS SUGGEST BY THE 0Z GFS. SCATTERED STORMS REMAIN POSSIBLE UNTIL THE NEXT BOUNDARY PUSHES INTO THE REGION ON SAT INTO SAT NIGHT. WITH THE BOUNDARY NEARBY...AN ISOLATED STORM OR TWO CANNOT BE RULED OUT ON TEMPERATURES THROUGH THE PERIOD WILL AVERAGE A BIT ABOVE NORMAL...WITH THE GREATEST DEPARTURES IN OVERNIGHT LOWS AS DEWPOINTS IN THE UPPER 60S TO LOWER 70S WILL LIMIT THE DIURNAL RANGES. THE WARMEST DAY IN WHICH HEAT INDICES COULD APPROACH 100 SHOULD BE ON THU...WHEN MAX T SHOULD REACH OR EXCEED 90 IN MOST AREAS OUTSIDE OF THE HIGHEST TERRAIN. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 745 AM EDT MON JUL 23 2012 SOME SCATTERED TO BROKEN CU IS TRYING TO FORM THROUGH THE MID- MORNING HOURS...MUCH LIKE YESTERDAY. THIS COULD PUT SOME TEMPORARY MVFR CEILING RESTRICTIONS AT THE TAF SITES...HOWEVER WILL ADVERTISE A PREVAILING SCATTERED GROUP FOR NOW. ISOLATED TO SCATTERED CONVECTION WILL THREATEN DURING THE AFTERNOON HOURS...BEFORE DWINDLING AT DUSK. WINDS WILL BE OUT OF THE WSW BETWEEN 5 AND 10 KTS. MVFR FOG MAY BE SEEN ONCE AGAIN DURING THE OVERNIGHT HOURS DEPENDING ON CLOUD COVER. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...GEOGERIAN LONG TERM....JP AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
724 AM EDT MON JUL 23 2012 .SYNOPSIS... WEAK DISTURBANCES AND INCREASING MOISTURE WILL BRING INCREASING SHOWERS AND ISOLATED THUNDERSTORMS TO THE REGION TODAY. A TROUGH APPROACHES FROM THE WEST TODAY MOVING INTO NEW ENGLAND LATE TONIGHT. IT WILL BE FOLLOWED BY A COLD FRONT TUESDAY MORNING. HIGH PRESSURE WILL BUILD IN FROM THE WEST TUESDAY NIGHT THROUGH WEDNESDAY. LOW PRESSURE WILL PASS JUST OF NEW ENGLAND ON THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... .UPDATE... CONVECTIVE SHOWERS MOVING ACROSS NH AND EASTERN MAINE AT THE MOMENT. QPF AMOUNTS HAVE BEEN LIGHT. HAVE ADJUSTED POPS AS WELL AS CLOUD COVER...HOURLY TEMPERATURE AND DEW POINT GRIDS. OTHERWISE FORECAST IS ON TRACK. && A FEW WARM ADVECTION SHOWERS IN PROGRESS THIS MORNING OVER SOUTHERN NH. 1 KM HRRR HAS THE BEST HANDLE ON THE CONVECTION AND SHOWS THE SHOWERS MOVING TOWARDS PORTLAND AND OFFSHORE OVER THE NEXT FEW HOURS. THIS ACTIVITY IS MORE STABLE THAN THE CONVECTION FARTHER SW WHICH HAS MORE LIGHTNING. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THIS AFTERNOON OVER NEW HAMPSHIRE AND THE NORTHERN COUNTIES AS UPPER LEVEL DIVERGENCE AND FORCING FOR ASCENT INCREASES. INSTABILITY SUPPORTS GENERAL THUNDERSTORMS WITH WEAK SHEAR IN PLACE. MODELS KEEP MOST OF THE ACTIVITY NORTH OF PORTLAND AND AUGUSTA. WESTERLY WINDS WILL HELP TEMPERATURES WARM INTO THE LOWER TO MID 80S AREAWIDE. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... FOG SHOULD DEVELOP TONIGHT WITH MOIST GROUND AVAILABLE AND LIGHT WINDS. SOME SHOWERS WILL DEVELOP OVER NEW HAMPSHIRE AND NORTHERN MAINE WITH THE PRE FRONTAL TROUGH/INCREASING FORCING FOR ASCENT AHEAD OF THE ACTUAL COLD FRONT. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE COLD FRONT WILL ARRIVE IN THE PRE DAWN HOURS IN NEW HAMPSHIRE. THESE WILL BE HEAVY RAIN PRODUCERS WITH PW VALUES AROUND 1.70 INCHES AND SLOW STORM MOTIONS. THUS FLOODING WILL BE A POSSIBILITY. THE FRONT ALONG WITH THE PRECIPITATION WILL MOVE EAST DURING THE MORNING HOURS AND EARLY AFTERNOON. SB CAPES HAVE THE POTENTIAL TO REACH 1500-2000 J/KG OVER THE COASTAL PLAIN WITH ABOUT 30 KTS OF SHEAR CONCENTRATED IN THE LOWEST 0-1 KM. WITH A BOUNDARY NEARBY ISOLATED TORNADOES ARE A CONCERN. TEMPERATURES SHOULD WARM INTO THE MID 70S NORTH TO MID 80S SOUTH DESPITE THE PRECIPITATION AND CLOUDS. CLOUD COVER SHOULD EXIT THE AREA BY MID AFTERNOON WITH GUSTY NW WINDS DEVELOPING BEHIND THE SYSTEM. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... FRONT AND UPPER LEVEL TROUGH AXIS MOVE OFFSHORE TUESDAY NIGHT... BRINGING ANY PRECIPITATION TO AN END. SURFACE HIGH PRESSURE BUILDS IN FROM THE WEST BEHIND THE FRONT. COOLER AND DRIER AIR WILL MOVE IN FOR WEDNESDAY ON NORTHERLY FLOW... THOUGH WARMER AIR BEGINS TO PUSH BACK IN FROM THE WEST LATER IN THE DAY. HIGHS WILL STILL RISE TO AROUND 80. FROM THIS POINT ON... FORECAST CONFIDENCE DECREASES. ALL MODELS ARE IN AGREEMENT ON A WEAK WAVE PUSHING ACROSS THE NORTHEAST ON THURSDAY... WITH SURFACE LOW PRESSURE PASSING NEAR SOUTHERN NEW ENGLAND. THE GFS IS THE MOST ROBUST WITH THIS FEATURE... SPREADING HEAVY RAINFALL INTO NEW HAMPSHIRE AND WESTERN MAINE. CMC MODEL TRACKS THE LOW FURTHER SOUTH... THOUGH STILL MAINTAINS ITS INTENSITY. 12Z ECMWF IS MUCH SLOWER AND WEAKER WITH THE FEATURE... HOLDING PRECIPITATION OFF UNTIL THURSDAY NIGHT OR FRIDAY. BEST SOLUTION APPEARS TO BE TO PAINT A CHANCE OF RAIN ACROSS THE SOUTHERN HALF OF THE AREA TO ACCOUNT FOR THE WAVE CROSSING THROUGH SOUTHERN NEW ENGLAND. GFS CLEARS THINGS OUT QUICKLY BEHIND THE LOW FOR FRIDAY... WITH DRY CONDITIONS. MEANWHILE... CMC MODEL KEEPS A TROUGH JUST OFF THE SOUTHERN NEW ENGLAND COASTLINE... WITH A CHANCE OF RAIN ACROSS SOUTHERN PARTS OF NEW HAMPSHIRE AND WESTERN MAINE. ECMWF FINALLY PUSHES THE INITIAL WAVE SLOWLY NEAR THE SOUTHERN NEW ENGLAND COAST... WITH HEAVIER RAIN MOVING ACROSS SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE. ONCE AGAIN... BEST SOLUTION APPEARS TO BE TO PAINT A CHANCE OF RAIN ACROSS THE SOUTHERN PART OF THE AREA TO ACCOUNT FOR A LINGERING TROUGH OR A MORE SLOWLY MOVING INITIAL WAVE. MODELS ARE IN MUCH BETTER AGREEMENT ON THE TIMING OF THE PRIMARY UPPER TROUGH AXIS CROSSING NEW ENGLAND SATURDAY NIGHT... WITH SHOWERS FORECAST FOR SATURDAY FOLLOWED BY CLEARING SUNDAY. IN GENERAL... EXPECT THE BEST CHANCE OF SHOWERS ACROSS SOUTHERN AREAS FROM THURSDAY THROUGH FRIDAY... WITH A PERIOD OF HEAVY RAIN POSSIBLE. ALTHOUGH THE ENTIRE PERIOD MAY NOT BE A WASH OUT. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... SHORT TERM...MAINLY VFR THROUGH TODAY EXCEPT IN SHOWERS AND THUNDERSTORMS WHERE VISIBILITY/CEILINGS WILL BE LOWER. THIS MORNING...WE MAY SEE BRIEF SHOWERS AT KLEB...KCON...KPSM...AND KHIE. ALSO THUNDERSTORMS LOOK MOST LIKELY THIS AFTERNOON AT THOSE SAME TERMINALS WHERE FORCING IS BEST. COLD FRONTAL PASSAGE WILL NOT AFFECT TERMINALS UNTIL AFTER 24/06Z. PATCHY FOG POSSIBLE THIS MORNING AND AGAIN TONIGHT. LONG TERM...GENERALLY VFR EXPECTED. RAIN AND MVFR/IFR CONDITIONS POSSIBLE ACROSS SOUTHERN AREAS THURSDAY AND FRIDAY. && .MARINE... SHORT TERM...SCA FOR SEAS NOW EXTENDED THROUGH TUESDAY MORNING FOR MUCH OF THE OCEAN ZONES. THUNDERSTORMS WILL BECOME A THREAT THIS AFTERNOON WITH BETTER CHANCES ON TUESDAY. LONG TERM...WINDS SHOULD STAY BELOW 25 KT THROUGH THE EXTENDED FORECAST... WITH WAVE HEIGHTS LESS THAN 5 FT. LOW PRESSURE TRACKING SOUTH OF NEW ENGLAND THURSDAY OR FRIDAY MAY INCREASE EASTERLY FLOW ACROSS THE WATERS... BUT SHOULD STAY FAR ENOUGH SOUTH TO KEEP WINDS BELOW 25 KT. && .EQUIPMENT... SPECIAL NOTE: COMMUNICATIONS CIRCUIT STILL OUT AT KRKD AND KLEW. TAF FOR KRKD WILL CONTINUE TO HAVE "AMD NOT SKED" UNTIL COMMUNICATIONS PROBLEMS ARE RESOLVED. AT THIS TIME WE HAVE NO ESTIMATE OF WHEN A RETURN TO SERVICE IS EXPECTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT TUESDAY FOR ANZ150-152-154. && $$ HANES/KIMBLE
AREA FORECAST DISCUSSION
NWS GRAY ME
325 AM EDT MON JUL 23 2012 .SYNOPSIS... WEAK DISTURBANCES AND INCREASING MOISTURE WILL BRING INCREASING SHOWERS AND ISOLATED THUNDERSTORMS TO THE REGION TODAY. A TROUGH APPROACHES FROM THE WEST TODAY MOVING INTO NEW ENGLAND LATE TONIGHT. IT WILL BE FOLLOWED BY A COLD FRONT TUESDAY MORNING. HIGH PRESSURE WILL BUILD IN FROM THE WEST TUESDAY NIGHT THROUGH WEDNESDAY. LOW PRESSURE WILL PASS JUST OF NEW ENGLAND ON THURSDAY. && .NEAR TERM /THROUGH TODAY/... A FEW WARM ADVECTION SHOWERS IN PROGRESS THIS MORNING OVER SOUTHERN NH. 1 KM HRRR HAS THE BEST HANDLE ON THE CONVECTION AND SHOWS THE SHOWERS MOVING TOWARDS PORTLAND AND OFFSHORE OVER THE NEXT FEW HOURS. THIS ACTIVITY IS MORE STABLE THAN THE CONVECTION FARTHER SW WHICH HAS MORE LIGHTNING. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THIS AFTERNOON OVER NEW HAMPSHIRE AND THE NORTHERN COUNTIES AS UPPER LEVEL DIVERGENCE AND FORCING FOR ASCENT INCREASES. INSTABILITY SUPPORTS GENERAL THUNDERSTORMS WITH WEAK SHEAR IN PLACE. MODELS KEEP MOST OF THE ACTIVITY NORTH OF PORTLAND AND AUGUSTA. WESTERLY WINDS WILL HELP TEMPERATURES WARM INTO THE LOWER TO MID 80S AREAWIDE. && .SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/... FOG SHOULD DEVELOP TONIGHT WITH MOIST GROUND AVAILABLE AND LIGHT WINDS. SOME SHOWERS WILL DEVELOP OVER NEW HAMPSHIRE AND NORTHERN MAINE WITH THE PRE FRONTAL TROUGH/INCREASING FORCING FOR ASCENT AHEAD OF THE ACTUAL COLD FRONT. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE COLD FRONT WILL ARRIVE IN THE PRE DAWN HOURS IN NEW HAMPSHIRE. THESE WILL BE HEAVY RAIN PRODUCERS WITH PW VALUES AROUND 1.70 INCHES AND SLOW STORM MOTIONS. THUS FLOODING WILL BE A POSSIBILITY. THE FRONT ALONG WITH THE PRECIPITATION WILL MOVE EAST DURING THE MORNING HOURS AND EARLY AFTERNOON. SB CAPES HAVE THE POTENTIAL TO REACH 1500-2000 J/KG OVER THE COASTAL PLAIN WITH ABOUT 30 KTS OF SHEAR CONCENTRATED IN THE LOWEST 0-1 KM. WITH A BOUNDARY NEARBY ISOLATED TORNADOES ARE A CONCERN. TEMPERATURES SHOULD WARM INTO THE MID 70S NORTH TO MID 80S SOUTH DESPITE THE PRECIPITATION AND CLOUDS. CLOUD COVER SHOULD EXIT THE AREA BY MID AFTERNOON WITH GUSTY NW WINDS DEVELOPING BEHIND THE SYSTEM. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... FRONT AND UPPER LEVEL TROUGH AXIS MOVE OFFSHORE TUESDAY NIGHT... BRINGING ANY PRECIPITATION TO AN END. SURFACE HIGH PRESSURE BUILDS IN FROM THE WEST BEHIND THE FRONT. COOLER AND DRIER AIR WILL MOVE IN FOR WEDNESDAY ON NORTHERLY FLOW... THOUGH WARMER AIR BEGINS TO PUSH BACK IN FROM THE WEST LATER IN THE DAY. HIGHS WILL STILL RISE TO AROUND 80. FROM THIS POINT ON... FORECAST CONFIDENCE DECREASES. ALL MODELS ARE IN AGREEMENT ON A WEAK WAVE PUSHING ACROSS THE NORTHEAST ON THURSDAY... WITH SURFACE LOW PRESSURE PASSING NEAR SOUTHERN NEW ENGLAND. THE GFS IS THE MOST ROBUST WITH THIS FEATURE... SPREADING HEAVY RAINFALL INTO NEW HAMPSHIRE AND WESTERN MAINE. CMC MODEL TRACKS THE LOW FURTHER SOUTH... THOUGH STILL MAINTAINS ITS INTENSITY. 12Z ECMWF IS MUCH SLOWER AND WEAKER WITH THE FEATURE... HOLDING PRECIPITATION OFF UNTIL THURSDAY NIGHT OR FRIDAY. BEST SOLUTION APPEARS TO BE TO PAINT A CHANCE OF RAIN ACROSS THE SOUTHERN HALF OF THE AREA TO ACCOUNT FOR THE WAVE CROSSING THROUGH SOUTHERN NEW ENGLAND. GFS CLEARS THINGS OUT QUICKLY BEHIND THE LOW FOR FRIDAY... WITH DRY CONDITIONS. MEANWHILE... CMC MODEL KEEPS A TROUGH JUST OFF THE SOUTHERN NEW ENGLAND COASTLINE... WITH A CHANCE OF RAIN ACROSS SOUTHERN PARTS OF NEW HAMPSHIRE AND WESTERN MAINE. ECMWF FINALLY PUSHES THE INITIAL WAVE SLOWLY NEAR THE SOUTHERN NEW ENGLAND COAST... WITH HEAVIER RAIN MOVING ACROSS SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE. ONCE AGAIN... BEST SOLUTION APPEARS TO BE TO PAINT A CHANCE OF RAIN ACROSS THE SOUTHERN PART OF THE AREA TO ACCOUNT FOR A LINGERING TROUGH OR A MORE SLOWLY MOVING INITIAL WAVE. MODELS ARE IN MUCH BETTER AGREEMENT ON THE TIMING OF THE PRIMARY UPPER TROUGH AXIS CROSSING NEW ENGLAND SATURDAY NIGHT... WITH SHOWERS FORECAST FOR SATURDAY FOLLOWED BY CLEARING SUNDAY. IN GENERAL... EXPECT THE BEST CHANCE OF SHOWERS ACROSS SOUTHERN AREAS FROM THURSDAY THROUGH FRIDAY... WITH A PERIOD OF HEAVY RAIN POSSIBLE. ALTHOUGH THE ENTIRE PERIOD MAY NOT BE A WASH OUT. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... SHORT TERM...MAINLY VFR THROUGH TODAY EXCEPT IN SHOWERS AND THUNDERSTORMS WHERE VISIBILITY/CEILINGS WILL BE LOWER. THIS MORNING...WE MAY SEE BRIEF SHOWERS AT KLEB...KCON...KPSM...AND KHIE. ALSO THUNDERSTORMS LOOK MOST LIKELY THIS AFTERNOON AT THOSE SAME TERMINALS WHERE FORCING IS BEST. COLD FRONTAL PASSAGE WILL NOT AFFECT TERMINALS UNTIL AFTER 24/06Z. PATCHY FOG POSSIBLE THIS MORNING AND AGAIN TONIGHT. LONG TERM...GENERALLY VFR EXPECTED. RAIN AND MVFR/IFR CONDITIONS POSSIBLE ACROSS SOUTHERN AREAS THURSDAY AND FRIDAY. && .MARINE... SHORT TERM...SCA FOR SEAS NOW EXTENDED THROUGH TUESDAY MORNING FOR MUCH OF THE OCEAN ZONES. THUNDERSTORMS WILL BECOME A THREAT THIS AFTERNOON WITH BETTER CHANCES ON TUESDAY. LONG TERM...WINDS SHOULD STAY BELOW 25 KT THROUGH THE EXTENDED FORECAST... WITH WAVE HEIGHTS LESS THAN 5 FT. LOW PRESSURE TRACKING SOUTH OF NEW ENGLAND THURSDAY OR FRIDAY MAY INCREASE EASTERLY FLOW ACROSS THE WATERS... BUT SHOULD STAY FAR ENOUGH SOUTH TO KEEP WINDS BELOW 25 KT. && .EQUIPMENT... SPECIAL NOTE: COMMUNICATIONS CIRCUIT STILL OUT AT KRKD AND KLEW. TAF FOR KRKD WILL CONTINUE TO HAVE "AMD NOT SKED" UNTIL COMMUNICATIONS PROBLEMS ARE RESOLVED. AT THIS TIME WE HAVE NO ESTIMATE OF WHEN A RETURN TO SERVICE IS EXPECTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT TUESDAY FOR ANZ150-152-154. && $$ HANES/KIMBLE
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
343 PM EDT MON JUL 23 2012 .SYNOPSIS... HIGH PRESSURE BUILDS EAST FROM THE PLAINS THROUGH TUESDAY...AS A SERIES OF WEAK DISTURBANCES TRACK FROM THE UPPER MIDWEST TO THE EAST COAST. A COLD FRONT SWEEPS THROUGH THE REGION TUESDAY NIGHT FOLLOWED BY HIGH PRESSURE BUILDING IN FROM THE NORTH WEDNESDAY. ANOTHER COLD FRONT CROSSES THE MID ATLANTIC LATE IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... SCT SHWRS/TSTMS CURRENTLY OVER THE PIEDMONT WILL SLOWLY SPREAD EAST THIS AFTN INTO ERLY EVNG. LACK OF FORCING WILL BE A MAIN INHIBITOR TOWARDS SVR THREAT AS BEST S/W ENERGY IS STILL OFF TO THE NW OVER EASTERN OH SO ANY CONVECTION WILL BE MAINLY TRIGGERED BY LEE TROF AND OUTFLOW BNDRYS. SPC HAS INCLUDED THE ENTIRE REGION IN A SLGT RISK FOR SVR WX AS CONDITIONS ARE FAVORABLE FOR ISO SVR STORMS DUE TO STEEP LO-LVL LAPSE RATES AND MLCAPE GREATER THAN 2500 J/KG PER LATEST RAP ANALYSIS. 0-6 KM BULK SHEAR IS FAIRLY WEAK (~20 KT) AND UNIDIRECTIONAL SO STORM ORGANIZATION WILL BE LIMITED. MAIN THREATS ARE DAMAGING WIND GUSTS AND HEAVY RAINFALL. ACTIVITY SHOULD DECREASE THIS EVNG FOLLOWING THE LOSS OF DAYTIME HEATING. FOG MAY BE POSSIBLE IN SOME AREAS BUT DEBRIS CLOUDINESS WILL LIMIT LOW CLOUD/FOG FORMATION. ERLY MRNG LOW TEMPS IN THE LOW TO MID 70S. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... BETTER CHC FOR STRONG STORMS ON TUE AS A POTENT MID-LVL S/W EMBEDDED WITHIN NW FLOW ALOFT PUSHES THROUGH THE MID ATLANTIC ALONGSIDE A PREFRONTAL TROF IN THE AFTN AND EVNG HRS. THERMODYNAMIC FIELDS ARE AGAIN CONDUCIVE TO SVR WX...WITH 0-6 KM BULK SHEAR GREATER THAN MON (30-35 KT). MAIN THREATS ARE AGAIN HEAVY RAIN AND DAMAGING WINDS. WILL CONTINUE TO REFLECT SEVERE WX THREAT IN HWO. OTHER BIG STORY WILL BE HOTTER TEMPS...EXACERBATED BY COMPRESSIONAL HEATING AHEAD OF AN APPROACHING COLD FRONT. THE EVENTUAL ONSET OF CONVECTIVE ACTIVITY WILL CAST SOME UNCERTAINTY ON ACTUAL MAXIMA. FORECAST MAXIMA ATTM GENERALLY IN THE MID 90S TUE...AND WITH HEAT INDICES CURRENTLY FORECASTED TO MAX OUT AROUND 101-105...HEAT ADVISORY CRITERIA WILL BE APPROACHED IN SOME AREAS. WILL HOLD OFF FOR NOW ON ANY HEAT HEADLINES ACROSS THE FA AS CONFIDENCE FOR REACHING CRITERIA IS STILL LOW DUE TO CLOUDS...PRECIP POTENTIAL...AND DOWNWARD TREND IN HI TEMPS WITH MUCH OF TDY`S 12Z GUIDANCE. AFOREMENTIONED ADVANCING S/W TROF ON TUE WILL PULL THE COLD FRONT THROUGH THE REGION TUE NGT/ERLY WED...USHERING IN DRIER CONDITIONS WED AS DEWPTS DROP INTO THE L0W 60S IN MOST SPOTS. HIGHS WILL ONLY BE IN THE UPR 80S TO LWR 90S. S/SW FLOW RETURNS THU AHEAD OF THE NEXT FRONTAL SYSTEM WITH TEMPS REACHING THE MID 90S. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... BROAD UPR LVL TROUGH TO RMN ANCHOR OVR THE NE CONUS W/ RIDGE OVR THE NATIONS MIDSECTION FOR THE EXTENDED PD...RESULTING IN NWLY FLO INTO THE MDATLC RGN. TIMING SYSTEMS IN SUCH A PATTERN DIFFICULT FROM THIS FAR OUT. CDFNT TO CROSS THE RGN THU NGT INTO FRI...THEN LINGER OVR THE CAROLINAS. SERIES OF WK AREAS OF SFC LO PRES FCST TO TRACK ALG THE LINGERING BNDRY. OVRALL...MNLY PCLDY W/ PRIMARILY DIURNAL POPS...ESP FRI AND AGN SAT. TEMPS AVGG A FEW DEGS F ABV NRML (THOUGH RMNG LARGELY W/ +1 STANDARD DEVIATION OF NRML). HI TEMPS IN THE L/M90S FRI...U80S TO L90S SAT AND SUN...AND 80S MON. LO TEMPS IN THE M/U70S THU NGT/FRI NGT...AND L/M70S SAT NGT/SUN NGT. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... AS OF 17Z...SCATTERED SHOWERS WERE DEVELOPING OVER THE REGION WITH TSTMS IN SOUTHWEST VIRGINIA. TSTMS ARE EXPECTED ACROSS MUCH OF THE AREA...ESPECIALLY AFTER 20Z. INCLUDED VCSH AT MOST OF THE TAF SITES WITH TEMPO GROUP AT RIC. WILL MONITOR FOR THE NEED TO INCLUDE TSTMS LATE THIS AFTN AND EVENING. CEILINGS WILL LOWER TO MVFR AT TIMES. CUMULUS SHOULD CLEAR BY LATE THIS EVENING. CEILING AND VSBY RESTRICTIONS TUESDAY MORNING WILL BE LIMITED BY A LIGHT SW WIND...WARMER SFC TEMPERATURES AND POSSIBLE CLOUD COVER. OUTLOOK...CHANCES FOR CONVECTION RETURN TUESDAY AFTN AS A COLD FRONT APPROACHES. FROM WEDNESDAY THROUGH FRIDAY...CONDITIONS WILL BE MAINLY DRY AND VFR. && .MARINE... NO SCA UFN. WNDS MNLY SSW TNGT INTO TUE MRNG BCMG W. FNTL BNDRY XPCD TO DROP SE ACRS THE WTRS FM LT TUE AFTN THROUGH EVE. SPDS TO RMN AOB 15 KT THROUGH TUE. A PD OF NNW WNDS XPCD POST FNT TUE NGT INTO WED. CONFIDENCE RMNS LO RIGHT NOW ON ABT OF LLVL SURGE FM THE N DVLPS (I.E., ENHANCED WINDSPEEDS/PSBL HEADLINE). MNLY CAPPED SPDS AT ABT 15 KT. MODELS HAVE WNDS BMCG SSW AGN BY THU. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAS/MAM NEAR TERM...MAS SHORT TERM...MAS/MAM LONG TERM...ALB AVIATION...LSA MARINE...ALB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
855 AM EDT MON JUL 23 2012 .SYNOPSIS... UPPER LEVEL DISTURBANCES IN NORTHWEST FLOW WILL BRING THE POTENTIAL FOR SEVERE WEATHER TODAY AND TOMORROW. THE PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEK...WITH WEDNESDAY THE MOST LIKELY CHANCE FOR A DRY DAY. && .NEAR TERM /THROUGH TONIGHT/... MODEL INITIALIZATIONS SEEM TO HAVE STARTED OFF THE WAVE OVER THE CENTRAL GREAT LAKES A BIT TOO FAR TO THE NORTH THIS MORNING. AS A RESULT...THE MODELS...INCLUDING THE HRRR REALLY ARE FAILING TO YIELD A DECENT PORTRAY OF THE ONGOING SCENARIO UPSTREAM OF THE CWA. CONVECTION HAS DEVELOPED IN THE EARLY MORNING HOURS FROM THE THUMB OF MICHIGAN BACK TOWARD NORTHERN INDIANA JUST AHEAD OF THE 500 MB SHORT WAVE TROUGH AXIS. THIS IS COINCIDENT WITH THE NOSE OF A MODEST ROUGHLY 30 KT LOW LEVEL JET NOSE ORIENTED IN A NORTHWEST TO SOUTHEAST DIRECTION THAT IS DIVING INTO THE LOWER GREAT LAKES. LAPSE RATES AHEAD OF THIS WAVE IN THE 850-700 MB LAYER ARE EXTREMELY IMPRESSIVE PER SOUNDINGS...EVEN THOUGH CAPE IS NOT NECESSARILY SURFACE BASED AT THIS HOUR. HOWEVER...ELEVATED CAPE VALUES ARE RUNNING UP TOWARD ROUGHLY 1000 J/KG WITH THIS WAVE...SO CONVECTION SHOULD HAVE NO PROBLEM HOLDING TOGETHER UNTIL THE BOUNDARY LAYER WARMS MORE LATER THIS MORNING. AS THE AFTERNOON ENSUES AND THE SHORT WAVE TROUGH MOVES FARTHER SOUTHEAST...CAPE VALUES RISE UP TOWARD AND ABOVE 2500 J/KG WITH BULK SHEAR VALUES FROM THE NEWEST GUIDANCE RUNNING UP TOWARD 45 KTS. ADDITIONALLY...0-3 KM HELICITY VALUES NOW RUN UP IN EXCESS OF 350 M2S-2 AND 0-1 KM HELICITY SURPASSES 150 M2S-2. AS A RESULT...SEVERE CONVECTION IS STILL EXPECTED...WITH DAMAGING WIND AND ISOLATED TORNADOES BEING THE MAJOR THREAT COMPONENTS. THE HIGHEST THREAT AREA WOULD SEEM TO BE FROM INDIANA TO ZANESVILLE AND ALL POINTS TO THE SOUTHEAST OF THAT LINE...INCLUDING METROPOLITAN PITTSBURGH...THOUGH NO PART OF THE FORECAST AREA CAN BE RULED OUT FROM THE THREAT OF SEVERE WEATHER AS THE SYSTEM MOVES THROUGH. FRIES && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... COLD FRONT CROSSING THE GREAT LAKES TODAY WILL THEN CROSS THE REGION TUESDAY. BEST UPPER SUPPORT WITH THE FRONT WILL BE ACROSS THE SOUTHWESTERN PORTIONS OF THE FORECAST AREA. DEPENDING ON EXACT TRACK OF THE SHORTWAVE...CO-LOCATION OF HIGHEST INSTABILITY AND SHEAR VALUES COULD IMPACT SOUTHEASTERN OHIO AND NORTHERN WEST VIRGINIA AND BRING ANOTHER CHANCE FOR SEVERE WEATHER. SPC DAY 2 CONVECTIVE OUTLOOK KEEPS SLIGHT RISK AREA GENERALLY SOUTH OF A LINE FROM ZANESVILLE TO MORGANTOWN. EVEN AS THE COLD FRONT PUSHES THROUGH...A LOW PRESSURE SYSTEM WILL BE SPINNING UP IN THE NORTHERN GREAT PLAINS...EXTENDING A WARM FRONT INTO KENTUCKY AND VIRGINIA. WITH THE WARM FRONT DRIFTING NORTH ON WEDNESDAY...LOCATIONS SOUTH AND WEST OF PITTSBURGH COULD SEE SOME SHOWERS OR THUNDERSTORMS. TEMPERATURES SHOULD BE NEAR NORMAL DURING THIS PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AN UPPER RIDGE OVER THE MIDWEST WILL SLIDE EASTWARD AND FLATTEN BY THURSDAY. A FAIRLY STRONG SHORT WAVE TROUGH IS PROGGED TO DIG INTO THE GREAT LAKES REGION FRIDAY AND MOVE EAST INTO NEW ENGLAND BY SUNDAY. KEPT SCATTERED SHOWERS AND THUNDERSTORMS IN FORECAST EACH DAY THROUGH SATURDAY...WITH DRY WEATHER EXPECTED SUNDAY AS A SURFACE HIGH BUILDS IN. FORECAST TEMPERATURES ARE CLOSE TO HPC GUIDANCE AND NEAR NORMAL THROUGH THE EXTENDED PERIOD. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... MID TO HIGH CLOUDS HAVE BEGUN TO MOVE OVER THE REGION AND CEILINGS WILL GRADUALLY BECOME OVERCAST LATE IN THE MORNING. APPROACHING SHORTWAVE TROUGH WILL HELP DEVELOP SCATTERED THUNDERSTORMS WITH MVFR VISIBILITY IN THE AFTERNOON. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... NO WIDESPREAD IFR WEATHER IS PREDICTED AT THIS TIME. DISTURBANCES IN NORTHWEST FLOW WILL MAINTAIN THE CHANCES FOR THUNDERSTORMS THROUGH THE PERIOD. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1257 PM CDT MON JUL 23 2012 .UPDATE...FOR THE 18Z AVIATION DISCUSSION BELOW... && .DISCUSSION.../ISSUED 419 AM CDT MON JUL 23 2012/ TWO THINGS STILL APPEAR ON TRACK WITH THIS FORECAST. ONE...TONIGHT THROUGH THURSDAY LOOK ACTIVE WITH MULTIPLE HEALTHY PRECIPITATION CHANCES. SECOND...MUCH COOLER AND DRIER AIR LOOKS TO BE IN STORE FOR THE END OF THE WEEK...POSSIBLY OUR FIRST ADVENTURE INTO BELOW NORMAL CONDITIONS THIS JULY...RIGHT AT THE END OF THE MONTH. WATER VAPOR IMAGERY THIS MORNING SHOWS WAVE THAT BROUGHT SOME SEVERE WEATHER N/NW OF THE MPX CWA SUNDAY IS NOW OFF OVER THE U.P. OF MICH...WITH NICE DRYING BEHIND IT OVER NRN MN. MONSOONAL MOIST PLUME IS COMING UP THROUGH THE CENTRAL ROCKIES AND LAYING OVER ACROSS THE NRN PLAINS AND INTO UPPER MS VALLEY. RAP SHOWS A WEAK SHORT WAVE CURRENTLY MOVING ACROSS CENTRAL SODAK AT 330 AM. A MORE SUBSTANTIAL WAVE WAS SPINNING ACROSS NRN WASH AND THIS IS THE ONE THAT WILL BE RESPONSIBLE FOR THE ACTIVE WEATHER THROUGH MID WEEK. FOR TODAY...WEAK FRONT/WIND SHIFT THAT IS SLIPPING THROUGH THE AREA RIGHT NOW WILL BE SETTLING DOWN ALONG THE IOWA BORDER THIS AFTERNOON. POOLING OF MOISTURE ALONG THE BOUNDARY WILL COMBINE WITH HIGHS BACK UP AROUND 90 WILL RESULT IN MLCAPE VALUES OF 2000-3000 J/KG. MPX AREA WILL CONTINUE TO BE ON SRN EDGE OF SLOWLY STRENGTHENING UPPER JET...SO CERTAINLY SHEAR PARAMETERS WILL BE IN PLACE WITH INSTABILITY TO HAVE A SEVERE THREAT ALONG THE BOUNDARY /WIND AND HAIL/. HOWEVER...VERY WARM EML /SEE 00Z OMAHA SOUNDING FROM LAST NIGHT/ WILL BE ADVECTING OVER THE FRONT DURING THE AFTERNOON. IN ADDITION...LLJ DOES NOT REALLY BECOME FAVORABLE FOR GENERATING CONVECTION UNTIL TONIGHT...AND THAT COMBINED WITH THE CAP SHOULD IN ALL LIKELIHOOD KEEP THE MPX AREA DRY THIS AFTERNOON...THOUGH DID LEAVE 20 POPS IN PLACE ACROSS S/SW PORTION OF THE CWA JUST IN CASE WAVE CURRENTLY OVER CENTRAL SODAK FINDS A WAY TO ALLOW SOMETHING TO BREAK THROUGH THE CAP. MORE LIKELY...CONVECTION SHOULD EXPAND IN COVERAGE RAPIDLY AFTER 3Z ON NOSE OF 20-25 KT LLJ THAT WILL BE RIDING UP AND OVER THE FRONTAL BOUNDARY. CONTINUED TO ADVERTISE A BAND OF LIKELIES FOR TONIGHT THAT MORE OR LESS FOLLOWED THE IDEA OF PRECIP PLACEMENT FROM THE GFS/SREF/SPC-WRF/ARW-WRF. BASED ON WHERE LLJ IS FORECAST TO SET UP...NAM LOOKS TOO FAR NE WITH CONVECTION TONIGHT. THIS ACTIVITY WILL PERSIST INTO TUESDAY MORNING ACROSS THE SE CWA...BUT BY TUESDAY AFTERNOON...WE END UP IN A BIT OF A COL AT H85 BETWEEN TONIGHTS LLJ AND THE NEXT LLJ PUSH EXPECTED FOR TUESDAY NIGHT...SO DO EXPECT A BREAK IN THE PRECIP COME TUESDAY AFTERNOON. TUESDAY NIGHT...WITH THE UPPER WAVE FORECAST TO BE ACROSS THE CENTRAL DAKOTAS...ROUND TWO OF THE LLJ WILL COME IN A BIT FARTHER NE THAN WHAT WE SEE FOR TONIGHT. ANTICIPATING BEST RAIN CHANCES TONIGHT TO BE SW OF 94...WHILE THINGS SHIFT NE OF 94 TUESDAY NIGHT. BESIDE THE LLJ AND ASSOCIATED WAA MOVING IN TUESDAY NIGHT...H85 TROUGH AND SFC FRONT WILL BE MOVING INTO WRN MN AS WELL...WHICH WOULD PROMOTE MORE SCATTERED ACTIVITY FARTHER TO THE WEST. AT ANY RATE...EXPECT THE KMPX RADAR SCOPE TO BE RATHER COLORFUL COME TUESDAY NIGHT. GOING INTO WEDNESDAY...THE SFC FRONT...IN THE FORM OF PROBABLY THE MOST LEGIT COLD FRONT WE HAVE SEEN IN JULY...WILL BE SLOWLY PUSHING EAST ACROSS THE AREA...WITH BEST PRECIP CHANCES WEDNESDAY AFTERNOON RESIDING ACROSS ERN AREAS...WITH WRN HALF OF THE CWA LIKELY BEING DRY WEDNESDAY AFTERNOON. HAVE POPS CONTINUING INTO WEDNESDAY NIGHT FOR COLLABORATION REASONS...BUT BASED ON TIMING OF FRONTAL MOVEMENT...WITH IT BASICALLY EAST OF THE MPX CWA BY 00Z ON WEDNESDAY EVENING...WOULD NOT BE SURPRISED IF WEDNESDAY NIGHT ENDS UP BEING DRY. GOING INTO THURSDAY...UPPER WAVE CURRENTLY OVER WASH WILL FINALLY BE DROPPING ACROSS NE MN INTO NRN WI. COOL TEMPS ALOFT WILL PROMOTE STEEP LAPS RATES THU AFTERNOON...WHICH SHOULD PROMOTE FAIRLY WIDESPREAD SHOWER/THUNDERSTORM ACTIVITY ACROSS THE ERN HALF OF THE MPX CWA THURSDAY AFTERNOON. THINGS LOOK TO DRY OUT QUICKLY THURSDAY NIGHT...AND WITH HIGH PRESSURE ADVECTING IN ON FRIDAY...WOULD SUSPECT CURRENT CHANCE POPS ACROSS ERN PORTION OF CWA TO BE A BIT OVERDONE. WITH THAT SAID...COOL MID LEVEL TEMPS LINGERING ACROSS ERN AREAS ON FRIDAY COULD RESULT IN ANOTHER AFTERNOON WITH SCT CONVECTION. WITH HIGH PRESSURE MOVING ACROSS THE AREA FRIDAY NIGHT/SATURDAY...WENT DRY WITH THE FORECAST. RETURN FLOW SETS UP SAT AFTERNOON THOUGH OUT WEST...SPREADING EAST ACROSS THE AREA COME SUNDAY. CAN NOT RULE OUT SOME STORMS ACROSS THE WEST SATURDAY...BUT BETTER CHANCES FOR PRECIP CERTAINLY LOOK TO COME IN SATURDAY NIGHT INTO SUNDAY AS THE ECMWF AT LEAST SHOWS ANOTHER NICE OVERRUNNING TYPE PRECIP EVENT SETTING UP. FOR TEMPERATURES...925-850 TEMPS OFF THE SREF/GEM/GFS/ECMWF FOR THIS AFTERNOON WOULD FAVOR 90S BEING CONFINED TO SOUTH-CENTRAL MN...WITH CLOUD COVER LIKELY SUPPRESSING TEMPS ACROSS CENTRAL MN AND FAVORED HIGHS TODAY TOWARD THE SREF/GEM SOLUTIONS. FOR TUESDAY AND WEDNESDAY...CLOUD COVER SHOULD HOLD TEMPS IN CHECK...BUT WAA ADVECTION OUT AHEAD OF THE FRONT WILL BRING IN SOME RATHER WARM AIR BOTH DAYS AND CERTAINLY A SUNNIER SITUATION THAN CURRENTLY BEING ADVERTISED WOULD RESULT IN HIGHS BEING A BIT CLOSE TO OR EVEN GREATER THAN 90 BOTH DAYS. A RARE SITE THIS JULY WILL THEN TAKE PLACE BEHIND THIS SYSTEM ON THURSDAY...COLD AIR ADVECTION. BY FRIDAY...MODELS ALL PRETTY CONSISTENT WITH HAVING 925-850 TEMPS DOWN AROUND 18C...WHICH WHEN MIXED DOWN WOULD ONLY YIELD HIGHS IN THE MID 70S TO AROUND 80. COMBINE THAT WITH DEWPS FALLING INTO THE UPPER 50S ON FRIDAY AND WE SHOULD END THE WEEK WITH ONE OF THE NICEST DAYS WE HAVE SEEN ALL SUMMER. FOR THE WEEKEND...RETURN FLOW AROUND THE BACKSIDE OF THE HIGH WILL START TO WARM THINGS UP...BUT EVEN THEN...HIGHS SHOULD ONLY CLIMB BACK UP INTO THE MID 80S. && .AVIATION.../18Z TAF ISSUANCE/ SCATTERED SHOWERS AND ISOLD THUNDER WILL BE POSSIBLE THIS AFTERNOON/EVE MAINLY ACROSS WEST/SOUTH CNTRL MN...MOST LIKELY AFFECTING KRWF. MORE WIDESPREAD CONVECTION WILL DEVELOP AFTER 02Z THIS EVE WHEN THE LLJ DEVELOPS. HAVE CENTERED SHRA/TS MENTION BETWEEN 06Z AND 12Z TUESDAY...ALTHOUGH THERE COULD BE ROGUE ACTIVITY ON EITHER SIDE OF THAT TIME FRAME. AFTER 12Z...SHOWERS ARE EXPECTED TO BE LINGERING ACROSS FAR EAST CENTRAL MN AND WEST CENTRAL WI UNTIL 15Z. LIGHT NORTHERLY WINDS WILL GRADUALLY BECOME EASTERLY IN DIRECTION BY THE END OF THE PERIOD. KMSP...ISOLATED SHOWERS CANNOT BE RULED OUT AFTER 00Z...BUT THE BULK OF THE ACTIVITY IS EXPECTED TO ARRIVE BETWEEN 05Z AND 11Z AT THE AIRPORT. THE THUNDER THREAT IS MOST PROBABLE BETWEEN 05Z AND 11Z AS THE LOW LEVEL JET INCREASES. NORTHERLY WINDS WILL SHIFT TO NORTHEASTERLY AROUND/AFTER SUNSET...AND THEN GRADUALLY VEER TO EASTERLY IN DIRECTION OVERNIGHT. /OUTLOOK/ WEDNESDAY...VFR/MVFR WITH SHRA/TSRA POSSIBLE EARLY. WINDS VARIABLE AT 5 KTS. THURSDAY...VFR WITH TSRA POSSIBLE. WINDS W/SW AT 5-10KTS. FRIDAY...VFR. WINDS NW 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ LRS/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
706 AM CDT MON JUL 23 2012 .UPDATE... UPDATED FOR THE 12Z AVIATION DISCUSSION BELOW. .DISCUSSION... TWO THINGS STILL APPEAR ON TRACK WITH THIS FORECAST. ONE...TONIGHT THROUGH THURSDAY LOOK ACTIVE WITH MULTIPLE HEALTHY PRECIPITATION CHANCES. SECOND...MUCH COOLER AND DRIER AIR LOOKS TO BE IN STORE FOR THE END OF THE WEEK...POSSIBLY OUR FIRST ADVENTURE INTO BELOW NORMAL CONDITIONS THIS JULY...RIGHT AT THE END OF THE MONTH. WATER VAPOR IMAGERY THIS MORNING SHOWS WAVE THAT BROUGHT SOME SEVERE WEATHER N/NW OF THE MPX CWA SUNDAY IS NOW OFF OVER THE U.P. OF MICH...WITH NICE DRYING BEHIND IT OVER NRN MN. MONSOONAL MOIST PLUME IS COMING UP THROUGH THE CENTRAL ROCKIES AND LAYING OVER ACROSS THE NRN PLAINS AND INTO UPPER MS VALLEY. RAP SHOWS A WEAK SHORT WAVE CURRENTLY MOVING ACROSS CENTRAL SODAK AT 330 AM. A MORE SUBSTANTIAL WAVE WAS SPINNING ACROSS NRN WASH AND THIS IS THE ONE THAT WILL BE RESPONSIBLE FOR THE ACTIVE WEATHER THROUGH MID WEEK. FOR TODAY...WEAK FRONT/WIND SHIFT THAT IS SLIPPING THROUGH THE AREA RIGHT NOW WILL BE SETTLING DOWN ALONG THE IOWA BORDER THIS AFTERNOON. POOLING OF MOISTURE ALONG THE BOUNDARY WILL COMBINE WITH HIGHS BACK UP AROUND 90 WILL RESULT IN MLCAPE VALUES OF 2000-3000 J/KG. MPX AREA WILL CONTINUE TO BE ON SRN EDGE OF SLOWLY STRENGTHENING UPPER JET...SO CERTAINLY SHEAR PARAMETERS WILL BE IN PLACE WITH INSTABILITY TO HAVE A SEVERE THREAT ALONG THE BOUNDARY /WIND AND HAIL/. HOWEVER...VERY WARM EML /SEE 00Z OMAHA SOUNDING FROM LAST NIGHT/ WILL BE ADVECTING OVER THE FRONT DURING THE AFTERNOON. IN ADDITION...LLJ DOES NOT REALLY BECOME FAVORABLE FOR GENERATING CONVECTION UNTIL TONIGHT...AND THAT COMBINED WITH THE CAP SHOULD IN ALL LIKELIHOOD KEEP THE MPX AREA DRY THIS AFTERNOON...THOUGH DID LEAVE 20 POPS IN PLACE ACROSS S/SW PORTION OF THE CWA JUST IN CASE WAVE CURRENTLY OVER CENTRAL SODAK FINDS A WAY TO ALLOW SOMETHING TO BREAK THROUGH THE CAP. MORE LIKELY...CONVECTION SHOULD EXPAND IN COVERAGE RAPIDLY AFTER 3Z ON NOSE OF 20-25 KT LLJ THAT WILL BE RIDING UP AND OVER THE FRONTAL BOUNDARY. CONTINUED TO ADVERTISE A BAND OF LIKELIES FOR TONIGHT THAT MORE OR LESS FOLLOWED THE IDEA OF PRECIP PLACEMENT FROM THE GFS/SREF/SPC-WRF/ARW-WRF. BASED ON WHERE LLJ IS FORECAST TO SET UP...NAM LOOKS TOO FAR NE WITH CONVECTION TONIGHT. THIS ACTIVITY WILL PERSIST INTO TUESDAY MORNING ACROSS THE SE CWA...BUT BY TUESDAY AFTERNOON...WE END UP IN A BIT OF A COL AT H85 BETWEEN TONIGHTS LLJ AND THE NEXT LLJ PUSH EXPECTED FOR TUESDAY NIGHT...SO DO EXPECT A BREAK IN THE PRECIP COME TUESDAY AFTERNOON. TUESDAY NIGHT...WITH THE UPPER WAVE FORECAST TO BE ACROSS THE CENTRAL DAKOTAS...ROUND TWO OF THE LLJ WILL COME IN A BIT FARTHER NE THAN WHAT WE SEE FOR TONIGHT. ANTICIPATING BEST RAIN CHANCES TONIGHT TO BE SW OF 94...WHILE THINGS SHIFT NE OF 94 TUESDAY NIGHT. BESIDE THE LLJ AND ASSOCIATED WAA MOVING IN TUESDAY NIGHT...H85 TROUGH AND SFC FRONT WILL BE MOVING INTO WRN MN AS WELL...WHICH WOULD PROMOTE MORE SCATTERED ACTIVITY FARTHER TO THE WEST. AT ANY RATE...EXPECT THE KMPX RADAR SCOPE TO BE RATHER COLORFUL COME TUESDAY NIGHT. GOING INTO WEDNESDAY...THE SFC FRONT...IN THE FORM OF PROBABLY THE MOST LEGIT COLD FRONT WE HAVE SEEN IN JULY...WILL BE SLOWLY PUSHING EAST ACROSS THE AREA...WITH BEST PRECIP CHANCES WEDNESDAY AFTERNOON RESIDING ACROSS ERN AREAS...WITH WRN HALF OF THE CWA LIKELY BEING DRY WEDNESDAY AFTERNOON. HAVE POPS CONTINUING INTO WEDNESDAY NIGHT FOR COLLABORATION REASONS...BUT BASED ON TIMING OF FRONTAL MOVEMENT...WITH IT BASICALLY EAST OF THE MPX CWA BY 00Z ON WEDNESDAY EVENING...WOULD NOT BE SURPRISED IF WEDNESDAY NIGHT ENDS UP BEING DRY. GOING INTO THURSDAY...UPPER WAVE CURRENTLY OVER WASH WILL FINALLY BE DROPPING ACROSS NE MN INTO NRN WI. COOL TEMPS ALOFT WILL PROMOTE STEEP LAPS RATES THU AFTERNOON...WHICH SHOULD PROMOTE FAIRLY WIDESPREAD SHOWER/THUNDERSTORM ACTIVITY ACROSS THE ERN HALF OF THE MPX CWA THURSDAY AFTERNOON. THINGS LOOK TO DRY OUT QUICKLY THURSDAY NIGHT...AND WITH HIGH PRESSURE ADVECTING IN ON FRIDAY...WOULD SUSPECT CURRENT CHANCE POPS ACROSS ERN PORTION OF CWA TO BE A BIT OVERDONE. WITH THAT SAID...COOL MID LEVEL TEMPS LINGERING ACROSS ERN AREAS ON FRIDAY COULD RESULT IN ANOTHER AFTERNOON WITH SCT CONVECTION. WITH HIGH PRESSURE MOVING ACROSS THE AREA FRIDAY NIGHT/SATURDAY...WENT DRY WITH THE FORECAST. RETURN FLOW SETS UP SAT AFTERNOON THOUGH OUT WEST...SPREADING EAST ACROSS THE AREA COME SUNDAY. CAN NOT RULE OUT SOME STORMS ACROSS THE WEST SATURDAY...BUT BETTER CHANCES FOR PRECIP CERTAINLY LOOK TO COME IN SATURDAY NIGHT INTO SUNDAY AS THE ECMWF AT LEAST SHOWS ANOTHER NICE OVERRUNNING TYPE PRECIP EVENT SETTING UP. FOR TEMPERATURES...925-850 TEMPS OFF THE SREF/GEM/GFS/ECMWF FOR THIS AFTERNOON WOULD FAVOR 90S BEING CONFINED TO SOUTH-CENTRAL MN...WITH CLOUD COVER LIKELY SUPPRESSING TEMPS ACROSS CENTRAL MN AND FAVORED HIGHS TODAY TOWARD THE SREF/GEM SOLUTIONS. FOR TUESDAY AND WEDNESDAY...CLOUD COVER SHOULD HOLD TEMPS IN CHECK...BUT WAA ADVECTION OUT AHEAD OF THE FRONT WILL BRING IN SOME RATHER WARM AIR BOTH DAYS AND CERTAINLY A SUNNIER SITUATION THAN CURRENTLY BEING ADVERTISED WOULD RESULT IN HIGHS BEING A BIT CLOSE TO OR EVEN GREATER THAN 90 BOTH DAYS. A RARE SITE THIS JULY WILL THEN TAKE PLACE BEHIND THIS SYSTEM ON THURSDAY...COLD AIR ADVECTION. BY FRIDAY...MODELS ALL PRETTY CONSISTENT WITH HAVING 925-850 TEMPS DOWN AROUND 18C...WHICH WHEN MIXED DOWN WOULD ONLY YIELD HIGHS IN THE MID 70S TO AROUND 80. COMBINE THAT WITH DEWPS FALLING INTO THE UPPER 50S ON FRIDAY AND WE SHOULD END THE WEEK WITH ONE OF THE NICEST DAYS WE HAVE SEEN ALL SUMMER. FOR THE WEEKEND...RETURN FLOW AROUND THE BACKSIDE OF THE HIGH WILL START TO WARM THINGS UP...BUT EVEN THEN...HIGHS SHOULD ONLY CLIMB BACK UP INTO THE MID 80S. && .AVIATION.../12Z TAF ISSUANCE/ PATCHY FOG DEVELOPED THIS MORNING IN AREAS NOT DOMINATED BY HIGH CLOUDS OVER THE LAST FEW HOURS. NO CEILING PROBLEMS AND FOG SHOULD BURN OFF BETWEEN 8AM-9AM IN MOST LOCATIONS. SMALL CHANCE FOR SOME THUNDER IN SOUTHWEST AND SOUTH CENTRAL AS EARLY AS 20-21Z. HOWEVER...DO NOT HAVE VERY HIGH CONFIDENCE IN THUNDERSTORMS UNTIL AFTER 00Z THIS EVENING WHEN THE LOW LEVEL JET DEVELOPS. THUNDERSTORMS COVERAGE IS EXPECTED TO BE GREATER IN SOUTHERN MN / WESTERN WI THAN CENTRAL MN. KMSP...NOW THAT THE AIRPORT HAS MORE PRONOUNCED NW WINDS...IT WILL MOST LIKELY REMAIN THAT WAY FOR THE REMAINDER OF THE DAY WITH A GRADUAL VEERING TO THE NORTHEAST THIS EVENING. THUNDER NOT COMPLETELY OUT OF THE QUESTION THIS AFTERNOON...BUT FEEL MUCH MORE CERTAIN WITH AT LEAST VICINITY THUNDER LATE THIS EVENING. /OUTLOOK/ TUESDAY NIGHT/WEDNESDAY...VFR/MVFR WITH TSRA POSSIBLE. WINDS E AT 10KTS. THURSDAY...VFR WITH TSRA POSSIBLE. WINDS SW AT 10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MPG/CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
419 AM CDT MON JUL 23 2012 .DISCUSSION... TWO THINGS STILL APPEAR ON TRACK WITH THIS FORECAST. ONE...TONIGHT THROUGH THURSDAY LOOK ACTIVE WITH MULTIPLE HEALTHY PRECIPITATION CHANCES. SECOND...MUCH COOLER AND DRIER AIR LOOKS TO BE IN STORE FOR THE END OF THE WEEK...POSSIBLY OUR FIRST ADVENTURE INTO BELOW NORMAL CONDITIONS THIS JULY...RIGHT AT THE END OF THE MONTH. WATER VAPOR IMAGERY THIS MORNING SHOWS WAVE THAT BROUGHT SOME SEVERE WEATHER N/NW OF THE MPX CWA SUNDAY IS NOW OFF OVER THE U.P. OF MICH...WITH NICE DRYING BEHIND IT OVER NRN MN. MONSOONAL MOIST PLUME IS COMING UP THROUGH THE CENTRAL ROCKIES AND LAYING OVER ACROSS THE NRN PLAINS AND INTO UPPER MS VALLEY. RAP SHOWS A WEAK SHORT WAVE CURRENTLY MOVING ACROSS CENTRAL SODAK AT 330 AM. A MORE SUBSTANTIAL WAVE WAS SPINNING ACROSS NRN WASH AND THIS IS THE ONE THAT WILL BE RESPONSIBLE FOR THE ACTIVE WEATHER THROUGH MID WEEK. FOR TODAY...WEAK FRONT/WIND SHIFT THAT IS SLIPPING THROUGH THE AREA RIGHT NOW WILL BE SETTLING DOWN ALONG THE IOWA BORDER THIS AFTERNOON. POOLING OF MOISTURE ALONG THE BOUNDARY WILL COMBINE WITH HIGHS BACK UP AROUND 90 WILL RESULT IN MLCAPE VALUES OF 2000-3000 J/KG. MPX AREA WILL CONTINUE TO BE ON SRN EDGE OF SLOWLY STRENGTHENING UPPER JET...SO CERTAINLY SHEAR PARAMETERS WILL BE IN PLACE WITH INSTABILITY TO HAVE A SEVERE THREAT ALONG THE BOUNDARY /WIND AND HAIL/. HOWEVER...VERY WARM EML /SEE 00Z OMAHA SOUNDING FROM LAST NIGHT/ WILL BE ADVECTING OVER THE FRONT DURING THE AFTERNOON. IN ADDITION...LLJ DOES NOT REALLY BECOME FAVORABLE FOR GENERATING CONVECTION UNTIL TONIGHT...AND THAT COMBINED WITH THE CAP SHOULD IN ALL LIKELIHOOD KEEP THE MPX AREA DRY THIS AFTERNOON...THOUGH DID LEAVE 20 POPS IN PLACE ACROSS S/SW PORTION OF THE CWA JUST IN CASE WAVE CURRENTLY OVER CENTRAL SODAK FINDS A WAY TO ALLOW SOMETHING TO BREAK THROUGH THE CAP. MORE LIKELY...CONVECTION SHOULD EXPAND IN COVERAGE RAPIDLY AFTER 3Z ON NOSE OF 20-25 KT LLJ THAT WILL BE RIDING UP AND OVER THE FRONTAL BOUNDARY. CONTINUED TO ADVERTISE A BAND OF LIKELIES FOR TONIGHT THAT MORE OR LESS FOLLOWED THE IDEA OF PRECIP PLACEMENT FROM THE GFS/SREF/SPC-WRF/ARW-WRF. BASED ON WHERE LLJ IS FORECAST TO SET UP...NAM LOOKS TOO FAR NE WITH CONVECTION TONIGHT. THIS ACTIVITY WILL PERSIST INTO TUESDAY MORNING ACROSS THE SE CWA...BUT BY TUESDAY AFTERNOON...WE END UP IN A BIT OF A COL AT H85 BETWEEN TONIGHTS LLJ AND THE NEXT LLJ PUSH EXPECTED FOR TUESDAY NIGHT...SO DO EXPECT A BREAK IN THE PRECIP COME TUESDAY AFTERNOON. TUESDAY NIGHT...WITH THE UPPER WAVE FORECAST TO BE ACROSS THE CENTRAL DAKOTAS...ROUND TWO OF THE LLJ WILL COME IN A BIT FARTHER NE THAN WHAT WE SEE FOR TONIGHT. ANTICIPATING BEST RAIN CHANCES TONIGHT TO BE SW OF 94...WHILE THINGS SHIFT NE OF 94 TUESDAY NIGHT. BESIDE THE LLJ AND ASSOCIATED WAA MOVING IN TUESDAY NIGHT...H85 TROUGH AND SFC FRONT WILL BE MOVING INTO WRN MN AS WELL...WHICH WOULD PROMOTE MORE SCATTERED ACTIVITY FARTHER TO THE WEST. AT ANY RATE...EXPECT THE KMPX RADAR SCOPE TO BE RATHER COLORFUL COME TUESDAY NIGHT. GOING INTO WEDNESDAY...THE SFC FRONT...IN THE FORM OF PROBABLY THE MOST LEGIT COLD FRONT WE HAVE SEEN IN JULY...WILL BE SLOWLY PUSHING EAST ACROSS THE AREA...WITH BEST PRECIP CHANCES WEDNESDAY AFTERNOON RESIDING ACROSS ERN AREAS...WITH WRN HALF OF THE CWA LIKELY BEING DRY WEDNESDAY AFTERNOON. HAVE POPS CONTINUING INTO WEDNESDAY NIGHT FOR COLLABORATION REASONS...BUT BASED ON TIMING OF FRONTAL MOVEMENT...WITH IT BASICALLY EAST OF THE MPX CWA BY 00Z ON WEDNESDAY EVENING...WOULD NOT BE SURPRISED IF WEDNESDAY NIGHT ENDS UP BEING DRY. GOING INTO THURSDAY...UPPER WAVE CURRENTLY OVER WASH WILL FINALLY BE DROPPING ACROSS NE MN INTO NRN WI. COOL TEMPS ALOFT WILL PROMOTE STEEP LAPS RATES THU AFTERNOON...WHICH SHOULD PROMOTE FAIRLY WIDESPREAD SHOWER/THUNDERSTORM ACTIVITY ACROSS THE ERN HALF OF THE MPX CWA THURSDAY AFTERNOON. THINGS LOOK TO DRY OUT QUICKLY THURSDAY NIGHT...AND WITH HIGH PRESSURE ADVECTING IN ON FRIDAY...WOULD SUSPECT CURRENT CHANCE POPS ACROSS ERN PORTION OF CWA TO BE A BIT OVERDONE. WITH THAT SAID...COOL MID LEVEL TEMPS LINGERING ACROSS ERN AREAS ON FRIDAY COULD RESULT IN ANOTHER AFTERNOON WITH SCT CONVECTION. WITH HIGH PRESSURE MOVING ACROSS THE AREA FRIDAY NIGHT/SATURDAY...WENT DRY WITH THE FORECAST. RETURN FLOW SETS UP SAT AFTERNOON THOUGH OUT WEST...SPREADING EAST ACROSS THE AREA COME SUNDAY. CAN NOT RULE OUT SOME STORMS ACROSS THE WEST SATURDAY...BUT BETTER CHANCES FOR PRECIP CERTAINLY LOOK TO COME IN SATURDAY NIGHT INTO SUNDAY AS THE ECMWF AT LEAST SHOWS ANOTHER NICE OVERRUNNING TYPE PRECIP EVENT SETTING UP. FOR TEMPERATURES...925-850 TEMPS OFF THE SREF/GEM/GFS/ECMWF FOR THIS AFTERNOON WOULD FAVOR 90S BEING CONFINED TO SOUTH-CENTRAL MN...WITH CLOUD COVER LIKELY SUPPRESSING TEMPS ACROSS CENTRAL MN AND FAVORED HIGHS TODAY TOWARD THE SREF/GEM SOLUTIONS. FOR TUESDAY AND WEDNESDAY...CLOUD COVER SHOULD HOLD TEMPS IN CHECK...BUT WAA ADVECTION OUT AHEAD OF THE FRONT WILL BRING IN SOME RATHER WARM AIR BOTH DAYS AND CERTAINLY A SUNNIER SITUATION THAN CURRENTLY BEING ADVERTISED WOULD RESULT IN HIGHS BEING A BIT CLOSE TO OR EVEN GREATER THAN 90 BOTH DAYS. A RARE SITE THIS JULY WILL THEN TAKE PLACE BEHIND THIS SYSTEM ON THURSDAY...COLD AIR ADVECTION. BY FRIDAY...MODELS ALL PRETTY CONSISTENT WITH HAVING 925-850 TEMPS DOWN AROUND 18C...WHICH WHEN MIXED DOWN WOULD ONLY YIELD HIGHS IN THE MID 70S TO AROUND 80. COMBINE THAT WITH DEWPS FALLING INTO THE UPPER 50S ON FRIDAY AND WE SHOULD END THE WEEK WITH ONE OF THE NICEST DAYS WE HAVE SEEN ALL SUMMER. FOR THE WEEKEND...RETURN FLOW AROUND THE BACKSIDE OF THE HIGH WILL START TO WARM THINGS UP...BUT EVEN THEN...HIGHS SHOULD ONLY CLIMB BACK UP INTO THE MID 80S. && .AVIATION.../06Z TAF ISSUANCE/ EARLY EVENING STORMS FROM NRN SD INTO NRN MN DISSIPATED LEAVING JUST SOME HIGH CLOUDS. WEAK FRONT IN NW MN TAKING ITS TIME SO MOST LOCALES WILL SEE LIGHT SW WINDS THE NEXT FEW HOURS. FOG IS A BIT OF A CONCERN. WARM AND HUMID AIRMASS REMAINS IN PLACE WITH FRONT NOT SCOURING OUT MUCH OF ANY MOISTURE. BEST CHANCE WILL BE CENTRAL MN WHERE ANY SPRINKLES TONIGHT WILL HELP WITH A LITTLE SURFACE MOISTURE. HAVE BROUGHT KSTC DOWN TO IFR IN FOG LATE TONIGHT. KRNH AND KEAU MAY ALSO SEE SOME IFR BUT FOR NOW HAVE LEFT THEM WITH MVFR VSBY. WEAK SHORT WAVE IN SWRN SD WILL REACH SRN MN MONDAY AFTER 15Z. MAIN EFFECT WILL BE SOME MID CLOUDS. STRONGER SHORT WAVE LOOKS TO INFRINGE ON MN MONDAY EVENING AND HAVE ADDED SOME SHOWERS. WESTERN WISC WILL HAVE TO WAIT UNTIL LATER MONDAY NIGHT FOR PRECIP. KMSP...LIGHT SW WINDS MAY TAKE A WHILE TO FLIP OVER TO THE NW...BUT SPEEDS WILL BE 5 KNOTS OR LESS ANYWAY. WITH DECENT TEMP DEWPOINT SPREAD THIS EVENING...DOUBT THERE WILL BE MUCH FOG BUT HAVE A 6SM VSBY MENTIONED FOR A COUPLE HOURS. OTHERWISE LOOKING AT MONDAY EVENING BEFORE MENTIONING ANY PRECIP WHEN BETTER SHORT WAVE ARRIVES. /OUTLOOK/ TUESDAY...VFR/MVFR WITH TSRA POSSIBLE. WINDS E AT 10KTS. WEDNESDAY...VFR/MVFR WITH TSRA POSSIBLE. WINDS E AT 10KTS. THURSDAY...VFR WITH TSRA POSSIBLE. WINDS SW AT 10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MPG/TDK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1248 PM CDT MON JUL 23 2012 .AVIATION...SKIES TO REMAIN CLR FOR THE MOST PART THE NEXT 24 HRS...THERE IS A POSSIBILITY OF SOME BKN MID LEVEL CEILINGS AND ISOLATED TSTMS THIS EVENING ACROSS NORTH CENTRAL AND NORTHWEST NEB. COVERAGE NOT EXPECTED TO BE ENOUGH TO INCLUDE IN THE KVTN TAF AT THIS TIME. SFC WINDS MOSTLY SOUTH AT 5 TO 15 KTS THROUGH TUESDAY MORNING. && .PREV DISCUSSION... /ISSUED 742 AM CDT MON JUL 23 2012/ UPDATE... TEMPS THIS MORNING APPEAR TO BE RUNNING A FEW DEGREES HIGHER THAN SUNDAY AM. THE RAP AND HRRR ARE SHOWING VERY WARM TEMPS AGAIN THIS AFTN. THE SUPER ENSEMBLE PEAKS AT 107 FOR LBF AND 108 FOR VTN...110 FOR KONL. THESE MODELS TYPICALLY INTRODUCE A 6 DEGREE SUPER ADIABATIC ADJUSTMENT AT THE SFC. A NEW TEMPERATURE FORECAST IS OUT WHICH GIVES A SLIGHT BUMP TO HIGH TEMPS THIS AFTN. ALSO...THE WARM FRONT HAS LIFTED RAPIDLY NORTH AND RAIN CHANCES WITH THE FRONT APPEAR TO BE AT AN END. SO POPS HAVE BEEN REMOVED FOR THE MORNING PERIOD ACROSS NRN NEB. PREV DISCUSSION... /ISSUED 357 AM CDT MON JUL 23 2012/ SYNOPSIS... THE LARGE SCALE PATTERN REMAINS RELATIVELY UNCHANGED AS COMPARED TO TWENTY-FOUR HOURS AGO WITH UPPER LEVEL RIDGING ENCOMPASSING MUCH OF THE CONTIGUOUS 48. HEIGHT FALLS OF UP TO 60DM ASSOCIATED WITH A STRONG UPPER LOW WERE NOTED WITH THE 00Z UPPER ANALYSIS ACROSS THE PACIFIC NORTHWEST AND COASTAL BRITISH COLUMBIA. THE LATEST ANALYSIS ALSO REVEALS A FAIRLY MODEST MID LEVEL SPEED MAX ROUNDING THE BASE OF THE UPPER LOW AND EXTENDING INTO FAR SOUTHERN ALBERTA. AT THE SURFACE...A BOUNDARY EXTENDS NORTHEAST ACROSS NORTH CENTRAL NEBRASKA FROM A DISORGANIZED AREA OF LOW PRESSURE OVER THE PANHANDLE. SEVERAL OUTFLOW BOUNDARIES ARE CURRENTLY BEING SAMPLED BY THE KLNX 88D...THE MOST NOTABLE ACROSS EASTERN PORTIONS OF CHERRY COUNTY. OTHERWISE MOST OF THE CONVECTIVE ACTIVITY HAS REMAINED NORTH OF THE SOUTH DAKOTA BORDER AND ACROSS THE WESTERN PANHANDLE EARLY THIS MORNING. AS OF 07Z...TEMPERATURES RANGE FROM THE MID 70S AT KOGA TO THE LOW TO MID 80S AT KVTN...KTIF...KONL AND KANW. DISCUSSION... NEAR TERM...TODAY THROUGH 12Z WEDNESDAY. MAIN FORECASTING CONCERNS CONTINUE TO REVOLVE AROUND ANOMALOUSLY HIGH MAXIMUM TEMPERATURES AND THE ASSOCIATED FIRE RISKS THROUGH TUESDAY AFTERNOON. THEREAFTER...PRECIPITATION CHANCES INCREASE LATE IN THE NEAR TERM WITH A SLIGHT REPRIEVE FROM THE TRIPLE DIGIT HEAT. NEAR TERM SOLUTIONS HAVE A GOOD HANDLE ON THE CURRENT SITUATION IN WHICH IT IS SHOWN THAT THE AFOREMENTIONED FRONTAL BOUNDARY WILL LIFT NORTH THIS MORNING AND STALL ACROSS THE SOUTHERN BORDER OF SOUTH DAKOTA. THE EXPECTED NORTHWARD ADVANCEMENT WILL ALLOW FOR WIDESPREAD TRIPLE DIGIT READINGS ACROSS THE ENTIRE CWA. GENERALLY EMPLOYED A BLEND OF THE WARMEST GUIDANCE /NAM/ TO THE ONGOING FORECAST WHICH SUGGESTS THE WARMEST READINGS WILL BE ALONG AND SOUTH OF THE STALLED BOUNDARY WHERE COMPRESSIONAL HEATING WILL BE MAXIMIZED. HIGHS WILL APPROACH RECORD TERRITORY FOR SUCH LOCATIONS AS KVTN...KANW...AND KONL...WHERE 106-108F IS NOT OUT OF THE QUESTION. MODEL OUTPUT SUGGESTS SLIGHTLY COOLER /ALBEIT A COUPLE DEGREES LESS/ FOR LOCATIONS SOUTH OF THE BOUNDARY...SUCH AS KLBF WHERE TEMPERATURES ROSE TO 108F ON SUNDAY. BUFR SOUNDING SHOW LESS EXPECTED MIXING TODAY THAN YESTERDAY FURTHER SOUTH OF THE BOUNDARY...WITH FORECAST MIXING VALUES ONLY ATTAINING 725MB. HAVE A HARD TIME BELIEVING THIS AND FEEL THE ATMOSPHERE WILL MIX DRY ADIABATICALLY WELL ABOVE THIS LEVEL. THE GOING FORECAST HIGH TEMPERATURE AT KLBF IS 105F FOR TODAY...THIS MAY NOT BE HIGH ENOUGH IF GREATER MIXING OCCURS. SIMILAR HIGHS WILL BE EXPECTED FOR TUESDAY...HOWEVER THE BOUNDARY IS SHOWN TO SLOWLY SAG SOUTH...POSSIBLY BISECTING NORTHWESTERN NEBRASKA BY MID AFTERNOON. GUIDANCE HAS BEEN SLOWLY CATCHING UP AND WARMING TEMPERATURES WITH EACH RUN FOR TUESDAY...AND FEEL THAT THE NUMBERS ARE STILL A BIT COOL...BUT LOWER 100S IS A GOOD START FOR ALL LOCATIONS SAVE NORTHWEST NEBRASKA WHERE UPPER 90S WILL BE LIKELY. THE HEAT ADVISORY IS VALID AND NEEDED THROUGH 02Z WEDNESDAY...NO CHANGES NEEDED AT THIS TIME. THE THREAT OF EXTREME FIRE BEHAVIOR WILL BE HIGH ONCE AGAIN TODAY AND TUESDAY ACROSS THE ENTIRE FORECAST AREA. STRENGTHENING SOUTH SOUTHWESTERLY RETURN FLOW IS EXPECTED TO LOWER TD/S BACK INTO THE UPPER 40S OR LOW 50S FOR A GOOD PORTION OF THE SAND HILLS THIS AFTERNOON. TD/T SPREADS OF GREATER THAN 50F ARE LIKELY OVER A GOOD PORTION OF THE FA...AND THESE LARGE SPREADS WOULD PROMOTE AFTERNOON RH VALUES OF LESS THAN 20 PERCENT. THERE WERE LOCALIZED AREAS ACROSS THE CENTRAL SAND HILLS WHERE RH VALUES LOWERED TO LESS THAN 10 PERCENT ON SUNDAY...AND GIVEN SIMILAR SOURCE REGION FOR THE TD/S...FEEL THAT THOSE NUMBER COULD BE REPLICATED TODAY IN LOCALIZED AREAS. GIVEN THAT WIND SPEEDS ARE EXPECTED TO FLIRT WITH RED FLAG CRITERIA AS SURFACE PRESSURE GRADIENT TIGHTENS AND DEEP MIXING OCCURS...WENT AHEAD AND ISSUED A RED FLAG WARNING FOR THE ENTIRE FA BEGINNING AT 17Z TODAY AND CONTINUING UNTIL 03Z TONIGHT. WILL LIKELY NEED ADDITIONAL FIRE HEADLINES FOR TUESDAY...BUT WILL WORK ONE DAY AT A TIME. ONTO PRECIPITATION CHANCES...HEIGHT FALLS ASSOCIATED WITH THE ADVANCING PACIFIC NW LOW WILL OCCUR ACROSS THE HIGH PLAINS OF EASTERN WYOMING LATE THIS AFTERNOON AND WORK IN CONJUNCTION WITH THE DEEPENING HIGH PLAINS SURFACE LOW. INCREASING LOW LEVEL CONVERGENCE WILL CONTRIBUTE TO ANOTHER ROUND OF STORM DEVELOPMENT OVER THE HIGH PLAINS OF WESTERN NEBRASKA AND POSSIBLY DRIFT NORTHEAST ACROSS OUR FAR NORTHWESTERN ZONES TODAY/TONIGHT. BUFR SOUNDINGS INDICATE THAT INSTABILITY AND SHEAR WILL REMAIN FAIRLY LIMITED...BUT GIVEN SUBSTANTIAL INVERTED SOUNDINGS...STRONG DOWNBURSTS WITH DRY LIGHTNING WOULD BE POSSIBLE. THE ACTIVITY ACROSS WESTERN NEBRASKA SHOULD BE DIURNALLY DRIVEN...THUS WOULD EXPECT STORMS TO WANE AFTER NIGHTFALL. A GREATER CHANCE OF PRECIPITATION ARRIVES TUESDAY NIGHT AND WEDNESDAY MORNING AS THE STRONG UPPER LOW TRANSLATES ACROSS SOUTHERN CANADA TOWARD THE GREAT LAKES REGION. THE SURFACE FRONTAL BOUNDARY IS SHOWN TO BE ALONG THE SOUTH DAKOTA BORDER TUESDAY AFTERNOON...BUT IS FORCED SOUTH AND EAST WITH THE ADVANCING LOW. THIS FRONT POSSIBLY WILL SERVE AS A FOCUS FOR STORM DEVELOPMENT LATE IN THE DAY AS IT TRANSLATES EAST ACROSS THE CWA. THE NAM CONTINUES TO BE THE MOST BULLISH IN TERMS OF PRECIPITATION CHANCES...WHEREAS THE GFS AND EURO LARGELY REMAIN DRY THROUGH THE NEAR TERM. FELT THAT LOW END SLIGHT CHANCE/CHANCE POPS ARE NOT ENTIRE OUT OF THE QUESTION AT THIS POINT...SO WILL MAINTAIN FOR NOW. EXTENDED...BEYOND 12Z WEDNESDAY. DEPENDING ON THE MODEL OF CHOICE PRECIPITATION CHANCES REMAIN THROUGH MUCH OF THE DAY WEDNESDAY AND EARLY THURSDAY...WITH MOSTLY THE EURO LEADING THE CHANGE. IT/S A FAIRLY SIGNIFICANT WAVE ROLLING THROUGH THE NORTHERN PLAINS...SO WILL NOT DISCOUNT THE BLENDED GUIDANCE YET AND MAINTAIN SLIGHT CHANCE/LOW CHANCE POPS FOR NOW. OTHERWISE THE PASSAGE OF THE UPPER TROUGH WILL AT LEAST FORCE THE FRONT SOUTHWARD THROUGH MIDWEEK AND ALLOW FOR COOLER TEMPERATURES /ALBEIT STILL IN THE MID 90S/ THROUGH THE END OF THE WORK WEEK. THEREAFTER RIDGING IS SHOWN TO BECOME ONCE AGAIN ESTABLISHED ACROSS THE WESTERN CONUS AND WESTERN HIGH PLAINS. RISING TEMPERATURES WITH LIMITED PRECIPITATION CHANCES WOULD BE ANTICIPATED. WILL LEAVE THE EXTENDED DRY FOR NOW BEYOND THURSDAY MORNING. && .LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR NEZ204-206-208>210-219. HEAT ADVISORY UNTIL 9 PM CDT /8 PM MDT/ TUESDAY FOR NEZ005>010- 024>029-036>038-057>059-069>071-094. && $$ AVIATION...TAYLOR
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
742 AM CDT MON JUL 23 2012 .UPDATE... TEMPS THIS MORNING APPEAR TO BE RUNNING A FEW DEGREES HIGHER THAN SUNDAY AM. THE RAP AND HRRR ARE SHOWING VERY WARM TEMPS AGAIN THIS AFTN. THE SUPER ENSEMBLE PEAKS AT 107 FOR LBF AND 108 FOR VTN...110 FOR KONL. THESE MODELS TYPICALLY INTRODUCE A 6 DEGREE SUPER ADIABATIC ADJUSTMENT AT THE SFC. A NEW TEMPERATURE FORECAST IS OUT WHICH GIVES A SLIGHT BUMP TO HIGH TEMPS THIS AFTN. ALSO...THE WARM FRONT HAS LIFTED RAPIDLY NORTH AND RAIN CHANCES WITH THE FRONT APPEAR TO BE AT AN END. SO POPS HAVE BEEN REMOVED FOR THE MORNING PERIOD ACROSS NRN NEB. && .PREV DISCUSSION... /ISSUED 616 AM CDT MON JUL 23 2012/ UPDATE... AVIATION... VFR IS EXPECTED MOST AREAS TODAY AND TONIGHT. A WARM FRONT WILL LIFT SLOWLY NORTH TODAY. THE FRONT IS EXPECTED TO BE THE FOCUS FOR ISOLATED TO SCATTERED SHOWER AND TSTM COVERAGE TODAY AND TONIGHT...MAINLY NORTH OF A LINE FROM ALLIANCE TO AINSWORTH. ELSEWHERE VFR. PREV DISCUSSION... /ISSUED 357 AM CDT MON JUL 23 2012/ SYNOPSIS... THE LARGE SCALE PATTERN REMAINS RELATIVELY UNCHANGED AS COMPARED TO TWENTY-FOUR HOURS AGO WITH UPPER LEVEL RIDGING ENCOMPASSING MUCH OF THE CONTIGUOUS 48. HEIGHT FALLS OF UP TO 60DM ASSOCIATED WITH A STRONG UPPER LOW WERE NOTED WITH THE 00Z UPPER ANALYSIS ACROSS THE PACIFIC NORTHWEST AND COASTAL BRITISH COLUMBIA. THE LATEST ANALYSIS ALSO REVEALS A FAIRLY MODEST MID LEVEL SPEED MAX ROUNDING THE BASE OF THE UPPER LOW AND EXTENDING INTO FAR SOUTHERN ALBERTA. AT THE SURFACE...A BOUNDARY EXTENDS NORTHEAST ACROSS NORTH CENTRAL NEBRASKA FROM A DISORGANIZED AREA OF LOW PRESSURE OVER THE PANHANDLE. SEVERAL OUTFLOW BOUNDARIES ARE CURRENTLY BEING SAMPLED BY THE KLNX 88D...THE MOST NOTABLE ACROSS EASTERN PORTIONS OF CHERRY COUNTY. OTHERWISE MOST OF THE CONVECTIVE ACTIVITY HAS REMAINED NORTH OF THE SOUTH DAKOTA BORDER AND ACROSS THE WESTERN PANHANDLE EARLY THIS MORNING. AS OF 07Z...TEMPERATURES RANGE FROM THE MID 70S AT KOGA TO THE LOW TO MID 80S AT KVTN...KTIF...KONL AND KANW. DISCUSSION... NEAR TERM...TODAY THROUGH 12Z WEDNESDAY. MAIN FORECASTING CONCERNS CONTINUE TO REVOLVE AROUND ANOMALOUSLY HIGH MAXIMUM TEMPERATURES AND THE ASSOCIATED FIRE RISKS THROUGH TUESDAY AFTERNOON. THEREAFTER...PRECIPITATION CHANCES INCREASE LATE IN THE NEAR TERM WITH A SLIGHT REPRIEVE FROM THE TRIPLE DIGIT HEAT. NEAR TERM SOLUTIONS HAVE A GOOD HANDLE ON THE CURRENT SITUATION IN WHICH IT IS SHOWN THAT THE AFOREMENTIONED FRONTAL BOUNDARY WILL LIFT NORTH THIS MORNING AND STALL ACROSS THE SOUTHERN BORDER OF SOUTH DAKOTA. THE EXPECTED NORTHWARD ADVANCEMENT WILL ALLOW FOR WIDESPREAD TRIPLE DIGIT READINGS ACROSS THE ENTIRE CWA. GENERALLY EMPLOYED A BLEND OF THE WARMEST GUIDANCE /NAM/ TO THE ONGOING FORECAST WHICH SUGGESTS THE WARMEST READINGS WILL BE ALONG AND SOUTH OF THE STALLED BOUNDARY WHERE COMPRESSIONAL HEATING WILL BE MAXIMIZED. HIGHS WILL APPROACH RECORD TERRITORY FOR SUCH LOCATIONS AS KVTN...KANW...AND KONL...WHERE 106-108F IS NOT OUT OF THE QUESTION. MODEL OUTPUT SUGGESTS SLIGHTLY COOLER /ALBEIT A COUPLE DEGREES LESS/ FOR LOCATIONS SOUTH OF THE BOUNDARY...SUCH AS KLBF WHERE TEMPERATURES ROSE TO 108F ON SUNDAY. BUFR SOUNDING SHOW LESS EXPECTED MIXING TODAY THAN YESTERDAY FURTHER SOUTH OF THE BOUNDARY...WITH FORECAST MIXING VALUES ONLY ATTAINING 725MB. HAVE A HARD TIME BELIEVING THIS AND FEEL THE ATMOSPHERE WILL MIX DRY ADIABATICALLY WELL ABOVE THIS LEVEL. THE GOING FORECAST HIGH TEMPERATURE AT KLBF IS 105F FOR TODAY...THIS MAY NOT BE HIGH ENOUGH IF GREATER MIXING OCCURS. SIMILAR HIGHS WILL BE EXPECTED FOR TUESDAY...HOWEVER THE BOUNDARY IS SHOWN TO SLOWLY SAG SOUTH...POSSIBLY BISECTING NORTHWESTERN NEBRASKA BY MID AFTERNOON. GUIDANCE HAS BEEN SLOWLY CATCHING UP AND WARMING TEMPERATURES WITH EACH RUN FOR TUESDAY...AND FEEL THAT THE NUMBERS ARE STILL A BIT COOL...BUT LOWER 100S IS A GOOD START FOR ALL LOCATIONS SAVE NORTHWEST NEBRASKA WHERE UPPER 90S WILL BE LIKELY. THE HEAT ADVISORY IS VALID AND NEEDED THROUGH 02Z WEDNESDAY...NO CHANGES NEEDED AT THIS TIME. THE THREAT OF EXTREME FIRE BEHAVIOR WILL BE HIGH ONCE AGAIN TODAY AND TUESDAY ACROSS THE ENTIRE FORECAST AREA. STRENGTHENING SOUTH SOUTHWESTERLY RETURN FLOW IS EXPECTED TO LOWER TD/S BACK INTO THE UPPER 40S OR LOW 50S FOR A GOOD PORTION OF THE SAND HILLS THIS AFTERNOON. TD/T SPREADS OF GREATER THAN 50F ARE LIKELY OVER A GOOD PORTION OF THE FA...AND THESE LARGE SPREADS WOULD PROMOTE AFTERNOON RH VALUES OF LESS THAN 20 PERCENT. THERE WERE LOCALIZED AREAS ACROSS THE CENTRAL SAND HILLS WHERE RH VALUES LOWERED TO LESS THAN 10 PERCENT ON SUNDAY...AND GIVEN SIMILAR SOURCE REGION FOR THE TD/S...FEEL THAT THOSE NUMBER COULD BE REPLICATED TODAY IN LOCALIZED AREAS. GIVEN THAT WIND SPEEDS ARE EXPECTED TO FLIRT WITH RED FLAG CRITERIA AS SURFACE PRESSURE GRADIENT TIGHTENS AND DEEP MIXING OCCURS...WENT AHEAD AND ISSUED A RED FLAG WARNING FOR THE ENTIRE FA BEGINNING AT 17Z TODAY AND CONTINUING UNTIL 03Z TONIGHT. WILL LIKELY NEED ADDITIONAL FIRE HEADLINES FOR TUESDAY...BUT WILL WORK ONE DAY AT A TIME. ONTO PRECIPITATION CHANCES...HEIGHT FALLS ASSOCIATED WITH THE ADVANCING PACIFIC NW LOW WILL OCCUR ACROSS THE HIGH PLAINS OF EASTERN WYOMING LATE THIS AFTERNOON AND WORK IN CONJUNCTION WITH THE DEEPENING HIGH PLAINS SURFACE LOW. INCREASING LOW LEVEL CONVERGENCE WILL CONTRIBUTE TO ANOTHER ROUND OF STORM DEVELOPMENT OVER THE HIGH PLAINS OF WESTERN NEBRASKA AND POSSIBLY DRIFT NORTHEAST ACROSS OUR FAR NORTHWESTERN ZONES TODAY/TONIGHT. BUFR SOUNDINGS INDICATE THAT INSTABILITY AND SHEAR WILL REMAIN FAIRLY LIMITED...BUT GIVEN SUBSTANTIAL INVERTED SOUNDINGS...STRONG DOWNBURSTS WITH DRY LIGHTNING WOULD BE POSSIBLE. THE ACTIVITY ACROSS WESTERN NEBRASKA SHOULD BE DIURNALLY DRIVEN...THUS WOULD EXPECT STORMS TO WANE AFTER NIGHTFALL. A GREATER CHANCE OF PRECIPITATION ARRIVES TUESDAY NIGHT AND WEDNESDAY MORNING AS THE STRONG UPPER LOW TRANSLATES ACROSS SOUTHERN CANADA TOWARD THE GREAT LAKES REGION. THE SURFACE FRONTAL BOUNDARY IS SHOWN TO BE ALONG THE SOUTH DAKOTA BORDER TUESDAY AFTERNOON...BUT IS FORCED SOUTH AND EAST WITH THE ADVANCING LOW. THIS FRONT POSSIBLY WILL SERVE AS A FOCUS FOR STORM DEVELOPMENT LATE IN THE DAY AS IT TRANSLATES EAST ACROSS THE CWA. THE NAM CONTINUES TO BE THE MOST BULLISH IN TERMS OF PRECIPITATION CHANCES...WHEREAS THE GFS AND EURO LARGELY REMAIN DRY THROUGH THE NEAR TERM. FELT THAT LOW END SLIGHT CHANCE/CHANCE POPS ARE NOT ENTIRE OUT OF THE QUESTION AT THIS POINT...SO WILL MAINTAIN FOR NOW. EXTENDED...BEYOND 12Z WEDNESDAY. DEPENDING ON THE MODEL OF CHOICE PRECIPITATION CHANCES REMAIN THROUGH MUCH OF THE DAY WEDNESDAY AND EARLY THURSDAY...WITH MOSTLY THE EURO LEADING THE CHANGE. IT/S A FAIRLY SIGNIFICANT WAVE ROLLING THROUGH THE NORTHERN PLAINS...SO WILL NOT DISCOUNT THE BLENDED GUIDANCE YET AND MAINTAIN SLIGHT CHANCE/LOW CHANCE POPS FOR NOW. OTHERWISE THE PASSAGE OF THE UPPER TROUGH WILL AT LEAST FORCE THE FRONT SOUTHWARD THROUGH MIDWEEK AND ALLOW FOR COOLER TEMPERATURES /ALBEIT STILL IN THE MID 90S/ THROUGH THE END OF THE WORK WEEK. THEREAFTER RIDGING IS SHOWN TO BECOME ONCE AGAIN ESTABLISHED ACROSS THE WESTERN CONUS AND WESTERN HIGH PLAINS. RISING TEMPERATURES WITH LIMITED PRECIPITATION CHANCES WOULD BE ANTICIPATED. WILL LEAVE THE EXTENDED DRY FOR NOW BEYOND THURSDAY MORNING. AVIATION... VFR IS EXPECTED MOST AREAS TODAY AND TONIGHT. ISOLATED TO SCATTERED TSTM COVERAGE IS EXPECTED TODAY AND TONIGHT...MAINLY NORTH OF A LINE FROM ALLIANCE TO AINSWORTH. ELSEWHERE VFR. && .LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 10 PM CDT /9 PM MDT/ THIS EVENING FOR NEZ204-206-208>210-219. HEAT ADVISORY UNTIL 9 PM CDT /8 PM MDT/ TUESDAY FOR NEZ005>010- 024>029-036>038-057>059-069>071-094. && $$ SHORT TERM/EXTENDED...CDC AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
344 PM EDT MON JUL 23 2012 .SYNOPSIS... SCATTERED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED ACROSS THE AREA THROUGH TONIGHT AHEAD OF A COLD FRONT MOVING SOUTHEAST TOWARD THE AREA FROM ONTARIO. A FEW STORMS COULD BE SEVERE THROUGH THIS EVENING. HIGH PRESSURE WILL BRING A RETURN TO DRY WEATHER TUESDAY THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 4 AM TUESDAY/... SCATTERED THUNDERSTORMS CONTINUE THIS AFTERNOON ALONG AND AHEAD OF A WEAK SURFACE TROUGH EXTENDING FROM CENTRAL NEW YORK SOUTH THROUGH CENTRAL PENNSYLVANIA. SPC ANALYSIS INDICATES THAT MLCAPES ACROSS THE REGION THIS AFTERNOON RANGE FROM 2000 TO 2500 J/KG. DEEP LAYER (0-6 KM) SHEAR VALUES HAVE BEEN ONLY MARGINALLY SUPPORTIVE OF ORGANIZED SEVERE WEATHER...ABOUT 25 TO 30 KTS... THROUGH MID- AFTERNOON. HOWEVER THIS ENVIRONMENT HAS BEEN SUFFICIENT TO GENERATE SOME SEVERE STORMS. A STRONG MID-UPPER LEVEL WIND SPEED MAX WILL APPROACH THE AREA LATE THIS AFTERNOON THROUGH THIS EVENING INCREASING THE WIND SHEAR SIGNIFICANTLY. 0-6 KM SHEAR VALUES ARE FORECAST TO INCREASE TO AROUND 40 KTS BY 03Z. STORMS MAY INCREASE IN INTENSITY AS THIS SPEED MAX APPROACHES THE AREA LATE THIS AFTERNOON... THEN EXPECT THUNDERSTORM ACTIVITY TO DIMINISH FOR A PERIOD THIS EVENING AS THE DRY AIR ALOFT SWEEPS OVER THE AREA INHIBITING THE CONVECTION. THIS BRIEF LULL MAY BE FOLLOWED BY ANOTHER ROUND OF SHOWERS AND STORMS LATER THIS EVENING INTO THE OVERNIGHT PERIOD AS A SURFACE COLD FRONT APPROACHES FROM THE NORTHWEST. RUC SOUNDINGS INDICATE THAT CAPES REMAIN ABOVE 1000 J/KG UNTIL WELL AFTER MIDNIGHT AND WITH STRONG SHEAR IN PLACE ANY STORMS THAT CAN DEVELOP ALONG THE COLD FRONT COULD ONCE AGAIN BECOME SEVERE. STORMS SHOULD FINALLY DIMINISH ACROSS THE AREA LATE TONIGHT AS THE COLD FRONT PASSES SOUTHEAST OF THE AREA. && .SHORT TERM /4 AM TUESDAY THROUGH WEDNESDAY/... QUIET WEATHER RETURNS THROUGH THIS PERIOD. HIGH PRESSURE BUILD SOUTHEAST ON TUESDAY BRINGING DRY COOLER WEATHER WITH GUSTY NORTHWEST WINDS. WEDNESDAY WILL BE DRY AND SEASONABLY WARM WITH HIGH PRESSURE MOVING ACROSS THE MID-ATLANTIC. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... AFTER A BEAUTIFUL WEDNESDAY...CONDITIONS WILL QUICKLY TAKE A TURN FOR THE WORSE WEDNESDAY NIGHT INTO THURSDAY AS THE FIRST OF SEVERAL DISTURBANCES BARE DOWN ON THE REGION. AS HIGHLIGHTED IN RECENT DAYS...A SERIES OF UPPER-LEVEL SHORTWAVES DIVING SOUTHEAST FROM A BUILDING RIDGE ACROSS THE NORTHERN ROCKIES COMBINED WITH A NEARLY STATIONARY UPPER LOW ACROSS NORTHERN QUEBEC WILL RESULT IN A STAGNANT UPPER-LEVEL PATTERN. UNDER THIS SCENARIO...VERY SLOW MOVING SHORTWAVE TROUGHS CUTOFF FROM THE MAIN UPPER-LEVEL WIND FIELDS WILL GRADUALLY MOVE SOUTHWEST TOWARDS OUR REGION IN WEST-NORTHWEST FLOW ALOFT. FCST MODELS ALL AGREE THAT THE FIRST ROUND OF SHWRS WILL BE UPON US BY 12Z THU AS STRONG L0W-LEVEL JET WINDS OF ROUGHLY 40 KTS ASCEND A NORTHWARD LIFTING WARM FRONT. ADDITIONAL FORCING WILL BE PROVIDED BY STRONG UPPER-LEVEL DIVERGENCE ALOFT AS REGION WILL RESIDE UNDER THE FAVORABLE LEFT ENTRANCE REGION OF AN ANTICYCLONICALLY CURVED JET STREAK ROUNDING THE BASE OF THE AFOREMENTIONED UPPER LOW ACROSS NORTHERN QUEBEC. CURRENTLY MODELS TAKE THE SFC LOW EAST ACROSS WESTERN AND CENTRAL NY THROUGH THE DAY ON THURSDAY...WITH THE HEAVIEST PRECIP AXIS SUGGESTED JUST NORTH OF OUR FCST AREA ACROSS NORTHERN NY AND SOUTHERN ONTARIO. THAT SAID...IF CONDITIONS WORK OUT AS ADVERTISED...MUCH NEEDED RAINFALL WILL OCCUR ACROSS THE NORTHERN FINGER LAKES AND WESTERN MOHAWK VALLEY. BEYOND THIS...THE GFS QUICKLY EXITS THE SFC LOW STAGE RIGHT WHICH WOULD SET UP A TEMPORARY LULL ON FRIDAY IN ADVANCE OF NEXT UPPER SHORTWAVE DISTURBANCE. THE ECMWF ON THE OTHER HAND SUGGEST THE SFC LOW WILL STALL OVER THE REGION WHICH WOULD LEAD TO CONTINUED RAIN CHANCES RIGHT THROUGH THE END OF THE WEEK. QUICK LOOK AT THE CANADIAN-CMC MODEL FAVORS THE SLOWER SOLUTION AS OFFERED BY THE ECMWF AND THUS WILL KEEP CHC POPS THROUGH FRIDAY. AS MENTIONED ABOVE...NEXT MAJOR TROUGH TO ENTER THE REGION BY SATURDAY WHICH WILL BRING RENEWED CHANCES FOR SHWRS AND STORMS BEFORE CONDITIONS BEGIN TO DRY OUT BY SUNDAY AS UPPER TROUGH PULLS AWAY FROM THE REGION. EXPECT NEAR TO BELOW AVERAGE TEMPS THROUGH THE PERIOD WITH CONTINUED RAIN CHANCES AND ABUNDANT CLOUD COVER ALOFT. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... SCATTERED THUNDERSTORMS WILL MOVE ACROSS THE AREA THROUGH LATE AFTERNOON WITH BRIEF MVFR CONDITIONS AT A FEW OF THE TAF SITES. A BREAK IN THE THUNDERSTORM ACTIVITY IS EXPECTED THIS EVENING... THEN ANOTHER ROUND OF SHOWERS OR ISOLATED THUNDERSTORMS IS POSSIBLE LATE TONIGHT WITH A COLD FRONTAL PASSAGE. THIS SECOND ROUND IS UNCERTAIN AT THIS TIME AND THEREFORE HAS NOT BEEN INCLUDED IN THE TAF`S. WINDS WILL BE MAINLY SW AT 5 TO 15 KTS THIS AFTERNOON WITH STRONGER GUSTS NEAR THUNDERSTORMS. WINDS WILL BECOME LIGHT AND VARIABLE THIS EVENING THEN SHIFT TO NORTHWEST BEHIND THE COLD FRONT AFTER 06Z. OUTLOOK... TUE...MAINLY VFR. TUE NGT...POSSIBLE MVFR/IFR VSBY RESTRICTIONS...ESPECIALLY AT ELM. WED...VFR. THU...RESTRICTIONS PSBL IN SHRA/TSRA...ESPECIALLY ELM/BGM/AVP. FRI...MAINLY VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MSE NEAR TERM...MSE SHORT TERM...MSE/SLI LONG TERM...CMG AVIATION...CMG
AREA FORECAST DISCUSSION
NWS ALBANY NY
739 AM EDT MON JUL 23 2012 .SYNOPSIS... A DISTURBANCE AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL BRING AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. SOME OF THE STORMS COULD BE STRONG OR EVEN SEVERE...ESPECIALLY TONIGHT NORTH AND WEST OF ALBANY. CANADIAN HIGH PRESSURE WILL BUILD TOWARD THE REGION TUESDAY AND BRIEFLY CONTROL OUR WEATHER THROUGH MID WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM...STILL FOLLOWING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FROM SOUTHERN NEW YORK STATE ALL THE WAY FROM BUFFALO`S AREA. BUFFALO WARNED ON ONE CELL. SO FAR...NOTHING IN OUR AREA EVEN CLOSE TO SEVERE. THESE APPEAR TO BE HONED INTO AN ELEVATED WARM FRONT. THE OVERALL TREND WAS THEM TO WEAKEN A LITTLE. THE IFR SATELLITE PICTURE INDICATED QUITE AN MCS NORTH OF THE ARROW OF MINNESOTA. THIS WILL THE MCS THAT MIGHT IMPACT US LATER TONIGHT. BACK TO THE PROBLEM AT HAND...BELIEVE THAT STORMS WILL BECOME MORE WIDELY SCATTERED AS THE WARM FRONT WEAKENS AND LIFTS NORTHWARD LATER THIS MORNING. THEN...ANOTHER PRE-FRONTAL TROUGH COULD PRODUCE ANOTHER ROUND OF SHOWERS AND STORMS THIS AFTERNOON. IT SHOULD BE NOTED THAT THE 0Z NAM CAME IN BACKING OFF THE QPF TO THE NORTH AND WEST OF ALBANY THIS AFTERNOON...IMPLYING MOST OF THE ACTIVITY THIS AFTERNOON REMAINS SOUTH. WILL KEEP WHAT WE HAD IN FOR NOW SINCE THIS IS JUST ONE MODEL ONE. THE LATEST HRRR THOUGH TENDS TO KEEP MOST OF THE STORMS FROM ALBANY SOUTH THROUGHOUT THE DAY. THE GFS AND EURO WERE NOT AS DISCRIMINATING WITH THE QPF. PWATS ARE AROUND 1.5 INCHES...INCREASING A LITTLE THROUGH THIS MORNING. DECIDED NOT TO USE ANY SORT OF ENHANCED WORDING WITH THESE STORMS AS THEY LOOK FAIRLY "RUN OF THE MILL." WHILE SOME CERTAINLY COULD HAVE SOME LOCALLY HEAVY RAINFALL...PROBABLY NOTHING OUT OF THE ORDINARY...AT LEAST SO FAR. AFTER SOME LINGERING SHOWERS AND THUNDERSTORMS EARLY...IT LOOKS AS IF THERE MIGHT BE A BREAK AS ONE SHORT WAVE MOVES EAST CUTTING OFF THE EML AT LEAST TEMPORARILY. WE BELIEVE THERE WILL BE SOME SUNSHINE WHICH WILL SERVE TO HEAT THINGS UP...PRODUCING MUCAPES UP TO 2000 J/KG LATER ON THIS AFTERNOON. THIS ALONG WITH ANOTHER PRE-FRONTAL TROUGH SETTING UP TO THE LEE OF THE APPALACHIANS...LOOK TO FIRE UP ANOTHER ROUND OF THUNDERSTORMS THIS AFTERNOON. THESE HAVE THE POTENTIAL TO BE MORE ROBUST AS MID LEVEL LAPSE RATES STEEPEN TO ABOUT 6.5 KM/C AND ANY CAP LOOKS TO ERODE. THE WIND FIELD LOOKS RELATIVE LIGHT AS 0-6KM BULK SHEAR IS ONLY AROUND A MODEST 20 KTS. HOWEVER...A HIGH EQUILIBRIUM LEVEL OVER 40,000 FEET SHOULD ALLOW FOR POTENTIALLY TALL UPDRAFTS THAT COULD CONTAIN PRODUCE PULSE TYPE STORMS...FEATURING LARGE HAIL AND MARGINALLY DESTRUCTIVE WINDS DUE TO HEAVY RAIN DRAGGING WHATEVER WIND IS ELEVATED RIGHT TO THE GROUND OVER A SMALL AREA (WET MICROBURST). THIS ACTIVITY LOOKS TO WANE AROUND SUNDOWN. HOWEVER...THE STRONGEST FEATURE WITH THIS SYSTEM...A POTENT SHORT WAVE CURRENTLY SEEN ACROSS THE ARROW HEAD OF MINNESOTA LOOKS TO MOVE INTO OUR REGION TONIGHT JUST AHEAD OF THE REAL COLD FRONT. AT THIS TIME...UPPER LEVEL TEMPERATURES COOL...WIDESPREAD ASCENT INCREASES AS THE AREA COMES UNDER THE LEFT UPPER LEVEL EXIT JET REGION . THE OVERALL WIND FIELD WILL INCREASE. THERE IS MODERATE POTENTIAL FOR A MCS TO DEVELOP AND TAKE AIM ACROSS MAINLY OUR NORTHWESTERN ZONES DURING THE LATTER PORTION OF THE EVENING INTO THE OVERNIGHT HOURS. THERE IS EVEN AN OUTSIDE CHANCE THAT THIS MCS COULD DEVELOP INTO A DERECHO AS THE LATEST NAM SUGGESTS A POOL OF HIGH INSTABILITY LINING UP FROM LAKE ONTARIO...SOUTHEAST INTO OUR PORTION OF OUR ADIRONDACKS. THE WIND ON TOP OF THIS ENHANCED INSTABILITY IS UNIDIRECTIONAL FROM A WNW DIRECTION WITH BULK SHEAR INCREASING TO OVER 30 KTS. THIS SCENARIO IS CERTAINLY NOT ETCHED IN STONE...BUT SOMETHING THAT WILL NEED TO BE MONITORED AS THE DAY WEARS ON. SPC PLACES MOST OF OUR REGION IN SLIGHT RISK FOR SEVERE THUNDERSTORMS TODAY AND TONIGHT SO WE WILL CERTAINLY USE ENHANCED WORDING IN OUR FORECAST...MAINLY TIMING THESE TO THIS AFTERNOON (WITH THE PULSE TYPE STORMS) AND LATER IN THE EVENING FOR THE POSSIBLE MCS. ADDED POSSIBLE HEAVY RAINFALL TO THE AFTERNOON THUNDERSTORMS AS WELL. WITH SOME SUNSHINE EXPECTED...DECIDED TO FOLLOW THE WARMER MAV NOS...WHICH GIVES HIGH TEMPERATURES WELL INTO THE 80S ACROSS MOST OF THE REGION...WITH SOME UPPER 70S ACROSS THE ADIRONDACKS. DEWPOINTS LOOK TO RAMP UP TOWARD 70 DEGREES SO IT WILL BE A HUMID ONE AS WELL. IT WILL REMAIN UNCOMFORTABLE OVERNIGHT FOR MOST AREAS WITH OVERNIGHT LOWS LOOK TO BE IN THE 60S. SPECIFIC CHANGES TO THIS ENHANCED UPDATE INCLUDED INCREASING COVERAGE TO NUMEROUS SOUTH OF ALBANY UNTIL MID MORNING AND ONLY MINOR RE-TOOLING OF THE HOURLY GRIDS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... THE ACTUAL SURFACE DEW POINT BOUNDARY AND BOUNDARY LAYER THERMAL GRADIENT ARE NOT FORECASTED TO TRACK THROUGH OUR REGION UNTIL TUESDAY. MOST OF THE ENERGY AND FORCING SHOULD BE GONE SO WILL JUST KEEP SLIGHT CHANCES FOR ADDITIONAL SHOWERS/THUNDERSTORMS REGION WIDE TO START THE DAY...TAPERING ANY POPS FROM NORTH AND WEST AS THE AFTERNOON WEARS ON. COLD ADVECTION SPREADS THROUGH THE REGION THROUGH THE DAY TUESDAY...SO PERIODS OF CLOUDS AND SUN...WITH INCREASING SUN LATER IN THE DAY. IT WILL BE STILL BE WARM ON TUESDAY...ESPECIALLY SOUTH OF THE CAPITAL DISTRICT WHERE TEMPERATURES COULD MAKE A RUN AT 90 IN THE MID HUDSON VALLEY. MOST OTHER PLACES WILL TOP OUT IN THE 80S...WITH ONLY 70S ACROSS THE ADIRONDACKS AND PORTIONS OF THE GREENS. DEWPOINTS WILL SLOWLY DROP THROUGH THE 60S...INTO THE 50S NORTH AND WEST OF ALBANY BY DAY/E END. THERE WILL BE A GUSTY BREEZE WHICH WHILE HELPING TO PROMOTE MIXING...SHOULD KEEP IT FROM FEELING UNBEARABLE DOWN IN THE MID HUDSON VALLEY. TUESDAY NIGHT...THE COLD FRONT WILL HAVE SLID SOUTH OF OUR REGION. THERE MIGHT BE A SECONDARY ONE WORKING THROUGH EARLY TUESDAY EVENING WITH LITTLE FANFARE OTHER THAN PERHAPS SOME PATCHY CLOUDS. IT STILL APPEARS THAT THE BOUNDARY LAYER WINDS COULD REMAIN UP MUCH OF THE NIGHT KEEPING A BREEZE GOING WHICH IN TURN...MIGHT PREVENT TEMPERATURES FALLING MORE THAN THEY WOULD HAVE IF THEY WENT CALM. FOR THIS REASON...LEANED WITH THE SLIGHTLY WARMER MAV NOS FOR OVERNIGHT LOWS. A REFRESHING AIR MASS WILL BE IN PLACE ON WEDNESDAY...STILL WITH A BREEZE OUT OF THE NORTHWEST 10 TO 20 MPH. H850 TEMPERATURES LOOK TO COOL TO ABOUT +10C NORTH TO ABOUT +12C SOUTH. WITH GOOD MIXING...WE LOOK FOR HIGH TEMPERATURES TO TOP OUT 80-85 IN VALLEY LOCATIONS...70S HIGHER TERRAIN. THERE SHOULD BE LOTS OF SUNSHINE THAT DAY WITH A FEW FAIR WEATHER CU. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... MEDIUM RANGE MODELS (GFS/ECMWF) SUGGEST THE LONG TERM PERIOD COULD ACTUALLY BE A WET PERIOD...WHICH IS SOMETHING THE ALY FORECAST AREA HAS NOT SEEN SINCE EARLY JUNE. ALTHOUGH THE ECMWF/NAM AND CANADIAN MODELS INDICATE THAT SHOWERS COULD ENTER THE WESTERN PART OF THE FORECAST AREA SHORTLY BEFORE SUNRISE ON THURSDAY...HAVE KEPT THE FORECAST DRY FOR WEDNESDAY NIGHT WITH LOWS IN THE UPPER 40S AND 50S. ON THURSDAY...ALL MODELS SHOW SURFACE AND UPPER LEVEL WAVES MOVING ACROSS THE REGION...WITH THE CENTER OF THE SURFACE LOW MOVING WEST TO EAST ACROSS THE REGION SOMEWHERE NEAR THE NY/PA BORDER...AND THEN EASTWARD ACROSS SOUTHERN NEW ENGLAND. THE MODELS SHOW A FAIRLY WIDESPREAD AREA OF PCPN ACROSS THE ENTIRE FORECAST AREA. MOST MODELS SHOW THE HIGHEST PCPN AMOUNTS ACROSS THE NORTHERN PART OF THE FORECAST AREA (ONE TO TWO INCHES). FOR NOW HAVE LIMITED THE POP FORECAST TO HIGH CHANCE LEVELS...AS HAVE MOST SURROUNDING OFFICES. HIGHS THURSDAY ARE FORECAST TO BE BETWEEN 70 AND 80...BUT IF PCPN MOVES IN AS FAST AS SOME OF THE MODELS SUGGEST (AROUND SUNRISE)... THEN AREAS NORTH OF THE SURFACE LOW TRACK MAY NOT SEE TEMPS RISE OUT OF THE 60S. AT THIS POINT THE GFS AND ECMWF BEGIN TO SHOW SOME SIGNIFICANT DISAGREEMENT. THE GFS ENDS THE PCPN ASSOCIATED WITH THE FIRST LOW PRESSURE SYSTEM SOMETIME THURSDAY NIGHT. IT THEN FORECASTS A DRY DAY FOR FRIDAY AS A SMALL RIDGE OF HIGH PRESSURE MOVES ACROSS THE REGION. ANOTHER UPPER LEVEL TROF AND SURFACE LOW ARE THEN FORECAST TO BRING A SECOND ROUND OF POTENTIALLY WIDESPREAD PCPN TO THE REGION ON SATURDAY AND EARLY SATURDAY NIGHT...FOLLOWED BY A MAINLY DRY DAY ON SUNDAY. HOWEVER...THE ECMWF SHOWS CONSISTENTLY HIGH LEVELS OF MOISTURE OVER THE REGION WITH PERIODS OF SHOWERS FOR THE ENTIRE PERIOD FROM THURSDAY THROUGH SUNDAY AS THE FRONTAL BOUNDARY ASSOCIATED WITH THE FIRST LOW PRESSURE SYSTEM IS FORECAST TO NEVER MOVE FAR ENOUGH SOUTH TO ALLOW FOR ANY CLEARING. HAVE NO PREFERENCE AS TO WHICH MODEL TO FAVOR AT THIS POINT SO WILL FORECAST LOW CHANCE POPS FRIDAY THRU SATURDAY AS A COMPROMISE BETWEEN THE TWO MODELS...THEN LOWER TO SLIGHT CHANCE POPS SATURDAY NIGHT AND SUNDAY. HAVE FORECAST HIGH TEMPS DURING THE FRIDAY THRU SUNDAY PERIOD NEAR OR SLIGHTLY BELOW NORMAL FOR NOW...BUT IF WIDESPREAD PCPN DOES MATERIALIZE ON ANY OF THESE DAYS...THEN EXPECT ACTUAL HIGHS TO BE UP TO 10 DEGREES LESS. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... EXCEPT DURING POSSIBLE CONVECTION...EXPECT MAINLY VFR CONDITIONS AT THE KALB/KGFL/KPOU/KPSF TAF SITES THROUGH THIS EVENING. CURRENTLY... AS OF 1145Z...CLUSTERS OF SHOWERS AND TSTMS CONTINUE TO MOVE ACROSS THE SOUTHERN PART OF THE ALY FORECAST AREA (GENERALLY SOUTH OF 1-90). THESE SHOWERS AND TSTMS WILL LIKELY AFFECT THE KPOU AND KPSF TAF SITES THRU ABOUT 14Z AND HAVE INCLUDED TEMPO GROUPS FOR THIS TO OCCUR WITH MVFR/IFR CONDITIONS. NO ORGANIZED AREA OF CONVECTION HEADING TOWARDS THE OTHER TAF SITES SO WILL ONLY INCLUDE VCSH FOR NOW AND UPDATE IF ANY OTHER CONVECTION POPS UP. LATER IN THE DAY...MAINLY VFR CONDITIONS WILL CONTINUE...BUT THE PASSING OF AN UPPER LEVEL TROF COULD RESULT IN AN ORGANIZED AREA OF CONVECTION AFFECTING THE REGION LATE THIS AFTERNOON AND EVENING. FOR NOW WILL FORECAST VCSH IN THE TAFS...WITH A 6 HOUR PROB 30 GROUP FOR STRONG CONVECTION WITH MVFR CIGS/VSBYS BETWEEN 23/21Z AND 24/03Z... IFR CONDITIONS ARE ALSO POSSIBLE IF A STORM HITS ANY OF THE TAF SITES. LATER TONIGHT MVFR FOG AND CIGS MAY FORM AT SOME TAF SITES... ESPECIALLY WHERE ANY CONVECTION OCCURS. SURFACE WINDS OUTSIDE OF TSTMS WILL GENERALLY BE SOUTH OR SOUTHWEST AT 5 TO 10 KTS WITH SOME GUSTS TO 15 KTS POSSIBLE. WIND GUSTS TO 30 KTS OR MORE ARE POSSIBLE THIS AFTERNOON AND EVENING. OUTLOOK... TUE...MAINLY VFR. CHC SHRA/TSRA. WED...VFR. NO SIG WX. THU-FRI...VFR/MVFR. CHC SHRA/TSRA. && .FIRE WEATHER... A DISTURBANCE AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS OUR REGION TODAY...ESPECIALLY THIS AFTERNOON...AND AGAIN LATER THIS EVENING. WHILE NOT QUITE A WET FLAG SITUATION...THESE SHOWERS LOOK TO BRING A QUARTER INCH OR MORE OF RAINFALL TO MUCH OF OUR REGION THROUGH TONIGHT. RH VALUES LOOK TO REMAIN ELEVATED...STARTING OUT 75-90 PERCENT AND ONLY DROPPING TO THE 50 TO 70 PERCENT RANGE...BACK UP TO NEAR 100 PERCENT OVERNIGHT. TUESDAY LOOKS LIKE A MAINLY DRY DAY WITH A GUSTY WESTERLY BREEZE...10 TO 20 MPH...GUSTING AS HIGH AS 30 MPH MOHAWK VALLEY AND HIGHER ELEVATIONS. A SECONDARY COLD FRONT COULD BRING AN ADDITIONAL SHOWER OR THUNDERSTORM ON AN ISOLATED BASIS. AFTERNOON RH VALUES LOOK TO DROP INTO THE MODERATE RANGE...35 TO 50 PERCENT. && .HYDROLOGY... NO MAJOR HYDRO PROBLEMS ARE ANTICIPATED THROUGH MUCH OF THIS WEEK. MORE UNSETTLED WEATHER IS EXPECTED THROUGH TONIGHT AS UPPER LEVEL TROUGH PLUNGES SOUTH FROM CANADA BRINGING THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS. SOME OF THESE COULD CONTAIN LOCALLY HEAVY RAINFALL BUT A WIDESPREAD HEAVY RAIN APPEARS UNLIKELY AT THIS TIME. RIVER BASIN AVERAGES ARE EXPECTED TO BE A HALF TO THREE QUARTERS OF AN INCH THROUGH MONDAY NIGHT...HIGHEST IN OUR NORTHWESTERN AREAS. THIS RAIN MIGHT BRING A MINOR RESPONSE ON SOME OF THE SMALLER RIVERS IN THE ADIRONDACKS BUT THE OVERALL IMPACT WILL BE MINOR. HEAVY DOWNPOURS...ESPECIALLY THIS AFTERNOON...COULD BRING SOME PONDING TO PLACES OF POOR DRAINAGE. AN ADDITIONAL SHOWER OR THUNDERSTORM IS POSSIBLE TUESDAY ON AN ISOLATED BASIS THEN DRY ON WEDNESDAY. AN POTENTIALLY UNSETTLED WEATHER PATTERN LOOKS TO BE SHAPING UP FOR THE END OF THE WEEK AS STRONG STATIONARY FRONT SETS UP TO OUR SOUTH AND PRETTY STRONG IMPULSES LOOK TO RIPPLE ALONG IT. THERE IS A POTENTIAL FOR SOME MUCH NEEDED RAINFALL DURING THIS PERIOD. STAY TUNED. 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 NEAR TERM...HWJIV SHORT TERM...HWJIV LONG TERM...GJM AVIATION...GJM FIRE WEATHER...HWJIV/NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
645 AM EDT MON JUL 23 2012 .SYNOPSIS... A DISTURBANCE AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL BRING AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. SOME OF THE STORMS COULD BE STRONG OR EVEN SEVERE...ESPECIALLY TONIGHT NORTH AND WEST OF ALBANY. CANADIAN HIGH PRESSURE WILL BUILD TOWARD THE REGION TUESDAY AND BRIEFLY CONTROL OUR WEATHER THROUGH MID WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM...STILL FOLLOWING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FROM SOUTHERN NEW YORK STATE ALL THE WAY FROM BUFFALO`S AREA. BUFFALO WARNED ON ONE CELL. SO FAR...NOTHING IN OUR AREA EVEN CLOSE TO SEVERE. THESE APPEAR TO BE HONED INTO AN ELEVATED WARM FRONT. THE OVERALL TREND WAS THEM TO WEAKEN A LITTLE. THE IFR SATELLITE PICTURE INDICATED QUITE AN MCS NORTH OF THE ARROW OF MINNESOTA. THIS WILL THE MCS THAT MIGHT IMPACT US LATER TONIGHT. BACK TO THE PROBLEM AT HAND...BELIEVE THAT STORMS WILL BECOME MORE WIDELY SCATTERED AS THE WARM FRONT WEAKENS AND LIFTS NORTHWARD LATER THIS MORNING. THEN...ANOTHER PRE-FRONTAL TROUGH COULD PRODUCE ANOTHER ROUND OF SHOWERS AND STORMS THIS AFTERNOON. IT SHOULD BE NOTED THAT THE 0Z NAM CAME IN BACKING OFF THE QPF TO THE NORTH AND WEST OF ALBANY THIS AFTERNOON...IMPLYING MOST OF THE ACTIVITY THIS AFTERNOON REMAINS SOUTH. WILL KEEP WHAT WE HAD IN FOR NOW SINCE THIS IS JUST ONE MODEL ONE. THE LATEST HRRR THOUGH TENDS TO KEEP MOST OF THE STORMS FROM ALBANY SOUTH THROUGHOUT THE DAY. THE GFS AND EURO WERE NOT AS DISCRIMINATING WITH THE QPF. PWATS ARE AROUND 1.5 INCHES...INCREASING A LITTLE THROUGH THIS MORNING. DECIDED NOT TO USE ANY SORT OF ENHANCED WORDING WITH THESE STORMS AS THEY LOOK FAIRLY "RUN OF THE MILL." WHILE SOME CERTAINLY COULD HAVE SOME LOCALLY HEAVY RAINFALL...PROBABLY NOTHING OUT OF THE ORDINARY...AT LEAST SO FAR. AFTER SOME LINGERING SHOWERS AND THUNDERSTORMS EARLY...IT LOOKS AS IF THERE MIGHT BE A BREAK AS ONE SHORT WAVE MOVES EAST CUTTING OFF THE EML AT LEAST TEMPORARILY. WE BELIEVE THERE WILL BE SOME SUNSHINE WHICH WILL SERVE TO HEAT THINGS UP...PRODUCING MUCAPES UP TO 2000 J/KG LATER ON THIS AFTERNOON. THIS ALONG WITH ANOTHER PRE-FRONTAL TROUGH SETTING UP TO THE LEE OF THE APPALACHIANS...LOOK TO FIRE UP ANOTHER ROUND OF THUNDERSTORMS THIS AFTERNOON. THESE HAVE THE POTENTIAL TO BE MORE ROBUST AS MID LEVEL LAPSE RATES STEEPEN TO ABOUT 6.5 KM/C AND ANY CAP LOOKS TO ERODE. THE WIND FIELD LOOKS RELATIVE LIGHT AS 0-6KM BULK SHEAR IS ONLY AROUND A MODEST 20 KTS. HOWEVER...A HIGH EQUILIBRIUM LEVEL OVER 40,000 FEET SHOULD ALLOW FOR POTENTIALLY TALL UPDRAFTS THAT COULD CONTAIN PRODUCE PULSE TYPE STORMS...FEATURING LARGE HAIL AND MARGINALLY DESTRUCTIVE WINDS DUE TO HEAVY RAIN DRAGGING WHATEVER WIND IS ELEVATED RIGHT TO THE GROUND OVER A SMALL AREA (WET MICROBURST). THIS ACTIVITY LOOKS TO WANE AROUND SUNDOWN. HOWEVER...THE STRONGEST FEATURE WITH THIS SYSTEM...A POTENT SHORT WAVE CURRENTLY SEEN ACROSS THE ARROW HEAD OF MINNESOTA LOOKS TO MOVE INTO OUR REGION TONIGHT JUST AHEAD OF THE REAL COLD FRONT. AT THIS TIME...UPPER LEVEL TEMPERATURES COOL...WIDESPREAD ASCENT INCREASES AS THE AREA COMES UNDER THE LEFT UPPER LEVEL EXIT JET REGION . THE OVERALL WIND FIELD WILL INCREASE. THERE IS MODERATE POTENTIAL FOR A MCS TO DEVELOP AND TAKE AIM ACROSS MAINLY OUR NORTHWESTERN ZONES DURING THE LATTER PORTION OF THE EVENING INTO THE OVERNIGHT HOURS. THERE IS EVEN AN OUTSIDE CHANCE THAT THIS MCS COULD DEVELOP INTO A DERECHO AS THE LATEST NAM SUGGESTS A POOL OF HIGH INSTABILITY LINING UP FROM LAKE ONTARIO...SOUTHEAST INTO OUR PORTION OF OUR ADIRONDACKS. THE WIND ON TOP OF THIS ENHANCED INSTABILITY IS UNIDIRECTIONAL FROM A WNW DIRECTION WITH BULK SHEAR INCREASING TO OVER 30 KTS. THIS SCENARIO IS CERTAINLY NOT ETCHED IN STONE...BUT SOMETHING THAT WILL NEED TO BE MONITORED AS THE DAY WEARS ON. SPC PLACES MOST OF OUR REGION IN SLIGHT RISK FOR SEVERE THUNDERSTORMS TODAY AND TONIGHT SO WE WILL CERTAINLY USE ENHANCED WORDING IN OUR FORECAST...MAINLY TIMING THESE TO THIS AFTERNOON (WITH THE PULSE TYPE STORMS) AND LATER IN THE EVENING FOR THE POSSIBLE MCS. ADDED POSSIBLE HEAVY RAINFALL TO THE AFTERNOON THUNDERSTORMS AS WELL. WITH SOME SUNSHINE EXPECTED...DECIDED TO FOLLOW THE WARMER MAV NOS...WHICH GIVES HIGH TEMPERATURES WELL INTO THE 80S ACROSS MOST OF THE REGION...WITH SOME UPPER 70S ACROSS THE ADIRONDACKS. DEWPOINTS LOOK TO RAMP UP TOWARD 70 DEGREES SO IT WILL BE A HUMID ONE AS WELL. IT WILL REMAIN UNCOMFORTABLE OVERNIGHT FOR MOST AREAS WITH OVERNIGHT LOWS LOOK TO BE IN THE 60S. SPECIFIC CHANGES TO THIS ENHANCED UPDATE INCLUDED INCREASING COVERAGE TO NUMEROUS SOUTH OF ALBANY UNTIL MID MORNING AND ONLY MINOR RE-TOOLING OF THE HOURLY GRIDS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... THE ACTUAL SURFACE DEW POINT BOUNDARY AND BOUNDARY LAYER THERMAL GRADIENT ARE NOT FORECASTED TO TRACK THROUGH OUR REGION UNTIL TUESDAY. MOST OF THE ENERGY AND FORCING SHOULD BE GONE SO WILL JUST KEEP SLIGHT CHANCES FOR ADDITIONAL SHOWERS/THUNDERSTORMS REGION WIDE TO START THE DAY...TAPERING ANY POPS FROM NORTH AND WEST AS THE AFTERNOON WEARS ON. COLD ADVECTION SPREADS THROUGH THE REGION THROUGH THE DAY TUESDAY...SO PERIODS OF CLOUDS AND SUN...WITH INCREASING SUN LATER IN THE DAY. IT WILL BE STILL BE WARM ON TUESDAY...ESPECIALLY SOUTH OF THE CAPITAL DISTRICT WHERE TEMPERATURES COULD MAKE A RUN AT 90 IN THE MID HUDSON VALLEY. MOST OTHER PLACES WILL TOP OUT IN THE 80S...WITH ONLY 70S ACROSS THE ADIRONDACKS AND PORTIONS OF THE GREENS. DEWPOINTS WILL SLOWLY DROP THROUGH THE 60S...INTO THE 50S NORTH AND WEST OF ALBANY BY DAY/E END. THERE WILL BE A GUSTY BREEZE WHICH WHILE HELPING TO PROMOTE MIXING...SHOULD KEEP IT FROM FEELING UNBEARABLE DOWN IN THE MID HUDSON VALLEY. TUESDAY NIGHT...THE COLD FRONT WILL HAVE SLID SOUTH OF OUR REGION. THERE MIGHT BE A SECONDARY ONE WORKING THROUGH EARLY TUESDAY EVENING WITH LITTLE FANFARE OTHER THAN PERHAPS SOME PATCHY CLOUDS. IT STILL APPEARS THAT THE BOUNDARY LAYER WINDS COULD REMAIN UP MUCH OF THE NIGHT KEEPING A BREEZE GOING WHICH IN TURN...MIGHT PREVENT TEMPERATURES FALLING MORE THAN THEY WOULD HAVE IF THEY WENT CALM. FOR THIS REASON...LEANED WITH THE SLIGHTLY WARMER MAV NOS FOR OVERNIGHT LOWS. A REFRESHING AIR MASS WILL BE IN PLACE ON WEDNESDAY...STILL WITH A BREEZE OUT OF THE NORTHWEST 10 TO 20 MPH. H850 TEMPERATURES LOOK TO COOL TO ABOUT +10C NORTH TO ABOUT +12C SOUTH. WITH GOOD MIXING...WE LOOK FOR HIGH TEMPERATURES TO TOP OUT 80-85 IN VALLEY LOCATIONS...70S HIGHER TERRAIN. THERE SHOULD BE LOTS OF SUNSHINE THAT DAY WITH A FEW FAIR WEATHER CU. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... COMING SOON. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... EXCEPT DURING POSSIBLE CONVECTION...EXPECT MAINLY VFR CONDITIONS AT THE KALB/KGFL/KPOU/KPSF TAF SITES FOR THE TAF PERIOD ENDING AT 06Z TUESDAY. CURRENTLY...AS OF 0545Z...A LARGE CLUSTER OF TSTMS WAS MOVING JUST SOUTH OF DUE EAST ACROSS THE CENTRAL AND SOUTHERN CATSKILLS. THIS CLUSTER WILL LIKELY AFFECT THE KPOU TAF SITE BETWEEN 07Z AND 11Z AND HAVE INCLUDED A TEMPO GROUP FOR THIS TO OCCUR WITH MVFR CONDITIONS...BUT IF THE CORE OF A PARTICULAR TSTM WHERE TO GO DIRECTLY OVER KPOU...IFR CIGS/VSBYS WOULD BE POSSIBLE. NO ORGANIZED AREA OF CONVECTION HEADING TOWARDS THE OTHER TAF SITES SO WILL ONLY INCLUDE VCSH FOR NOW AND UPDATE IF ANY OTHER CONVECTION POPS UP. WITH A DECENT SOUTHERLY FLOW AT ALL THE TAF SITES EARLY THIS MORNING...NO FOG ISSUES ARE EXPECTED. DURING THE DAY...MAINLY VFR CONDITIONS WILL CONTINUE...BUT THE PASSING OF AN UPPER LEVEL TROF COULD RESULT IN AN ORGANIZED AREA OF CONVECTION AFFECTING THE REGION LATE THIS AFTERNOON AND EVENING. FOR NOW WILL FORECAST VCSH IN THE TAFS...WITH A 6 HOUR PROB 30 GROUP FOR STRONG CONVECTION WITH MVFR CIGS/VSBYS BETWEEN 23/19Z AND 24/01Z... EXCEPT BETWEEN 23/20Z AND 24/02Z AT KPSF. IFR CONDITIONS ARE ALSO POSSIBLE IF A STORM HITS ANY OF THE TAF SITES. SURFACE WINDS OUTSIDE OF TSTMS WILL GENERALLY BE SOUTH OR SOUTHWEST AT 5 TO 10 KTS WITH SOME GUSTS TO 15 KTS POSSIBLE. WIND GUSTS TO 30 KTS OR MORE ARE POSSIBLE THIS AFTERNOON AND EVENING. OUTLOOK... LATE MON NGT-TUE...MAINLY VFR. CHC SHRA/TSRA. WED...VFR. NO SIG WX. THU-FRI...VFR/MVFR. CHC SHRA/TSRA. && .FIRE WEATHER... A DISTURBANCE AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS OUR REGION TODAY...ESPECIALLY THIS AFTERNOON...AND AGAIN LATER THIS EVENING. WHILE NOT QUITE A WET FLAG SITUATION...THESE SHOWERS LOOK TO BRING A QUARTER INCH OR MORE OF RAINFALL TO MUCH OF OUR REGION THROUGH TONIGHT. RH VALUES LOOK TO REMAIN ELEVATED...STARTING OUT 75-90 PERCENT AND ONLY DROPPING TO THE 50 TO 70 PERCENT RANGE...BACK UP TO NEAR 100 PERCENT OVERNIGHT. TUESDAY LOOKS LIKE A MAINLY DRY DAY WITH A GUSTY WESTERLY BREEZE...10 TO 20 MPH...GUSTING AS HIGH AS 30 MPH MOHAWK VALLEY AND HIGHER ELEVATIONS. A SECONDARY COLD FRONT COULD BRING AN ADDITIONAL SHOWER OR THUNDERSTORM ON AN ISOLATED BASIS. AFTERNOON RH VALUES LOOK TO DROP INTO THE MODERATE RANGE...35 TO 50 PERCENT. && .HYDROLOGY... NO MAJOR HYDRO PROBLEMS ARE ANTICIPATED THROUGH MUCH OF THIS WEEK. MORE UNSETTLED WEATHER IS EXPECTED THROUGH TONIGHT AS UPPER LEVEL TROUGH PLUNGES SOUTH FROM CANADA BRINGING THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS. SOME OF THESE COULD CONTAIN LOCALLY HEAVY RAINFALL BUT A WIDESPREAD HEAVY RAIN APPEARS UNLIKELY AT THIS TIME. RIVER BASIN AVERAGES ARE EXPECTED TO BE A HALF TO THREE QUARTERS OF AN INCH THROUGH MONDAY NIGHT...HIGHEST IN OUR NORTHWESTERN AREAS. THIS RAIN MIGHT BRING A MINOR RESPONSE ON SOME OF THE SMALLER RIVERS IN THE ADIRONDACKS BUT THE OVERALL IMPACT WILL BE MINOR. HEAVY DOWNPOURS...ESPECIALLY THIS AFTERNOON...COULD BRING SOME PONDING TO PLACES OF POOR DRAINAGE. AN ADDITIONAL SHOWER OR THUNDERSTORM IS POSSIBLE TUESDAY ON AN ISOLATED BASIS THEN DRY ON WEDNESDAY. AN POTENTIALLY UNSETTLED WEATHER PATTERN LOOKS TO BE SHAPING UP FOR THE END OF THE WEEK AS STRONG STATIONARY FRONT SETS UP TO OUR SOUTH AND PRETTY STRONG IMPULSES LOOK TO RIPPLE ALONG IT. THERE IS A POTENTIAL FOR SOME MUCH NEEDED RAINFALL DURING THIS PERIOD. STAY TUNED. 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 NEAR TERM...HWJIV SHORT TERM...HWJIV LONG TERM...GJM AVIATION...GJM FIRE WEATHER...HWJIV/NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
200 AM EDT MON JUL 23 2012 .SYNOPSIS... A DISTURBANCE AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH NIGHT. CANADIAN HIGH PRESSURE WILL BUILD TOWARD THE REGION TUESDAY AND CONTROL OUR WEATHER THROUGH MID WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 130 AM...A LINE OF CONVECTION (MAINLY SHOWERS) WAS MOVING OUT OF THE NORTHERN TACONICS...NORTH TO THE SOUTHERN GREENS. ANOTHER CLUSTER OF SHOWERS AND THUNDERSTORMS WAS MOVING INTO THE CATSKILLS. THE 00Z NAM EXPANDS THIS REGION INTO AN AREA PRODUCING OVER HALF AN INCH OF RAIN OVERNIGHT FROM THE CAPITAL DISTRICT AND POINTS EASTWARD. WHILE WE BELIEVE THIS IS OVERDONE...THIS CONVECTION COULD BE PUTTING LOCALIZED CORES OF HALF AN INCH OR MORE. SO FAR...NOTHING SEVERE OR EVEN "STRONG". THESE AREAS OF SCATTERED SHOWERS/STORMS WERE THE RESULT OF WARM AIR ADVECTION...A PRE-FRONTAL TROUGH (WITH MORE OF THESE EXPECTED LATER ON MONDAY) AND PERHAPS A LOW LEVEL JET DEVELOPING. THE 00Z ALY RAOB INDICATED A CAP AROUND 20,000 SO WE ARE NOT LOOKING FOR ANYTHING TO BECOME SEVERE. THE HRRR HAS NOT DONE A GOOD JOB REPRESENTING THIS CONVECTION. WE BELIEVE THE ACTIVITY OVER THE CATSKILLS SHOULD CONTINUE TO PROPAGATE EASTWARD INTO THE AREA OF PRE-FRONTAL TROUGH. ELSEWHERE...WE WILL CONTINUE WITH SLIGHT CHANCES OF SHOWERS/THUNDERSTORMS AS THE REMAINDER OF THE REGION IS UNDERGOING WEAK ASCENT. OTHERWISE...EXPECT ANOTHER WARM AND INCREASINGLY HUMID NIGHT. WITH THE CLOUDS AND SOME WIND...TEMPS WERE STILL IN THE 70S IN SOME AREAS. HAVE THEREFORE RAISED OVERNIGHT MINS A BIT...WITH 65-70 EXPECTED IN MUCH OF THE HUDSON/MOHAWK RIVER VALLEYS...AND 60-65 ELSEWHERE. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... UPPER IMPULSE AND COLD FRONT BEGIN TO APPROACH THROUGH MONDAY...BUT BEFORE THE FRONT CAN TRACK INTO THE REGION...THERE IS SOME SUGGESTION IN GUIDANCE THAT A PRE FRONTAL TROUGH COULD FORM AHEAD OF THE FRONT IN OUR REGION MONDAY AFTERNOON AND EVENING. BOUNDARY LAYER WINDS INCREASE AND MIDLEVEL LAPSE RATES ARE STILL PREDICTED TO STEEPEN. AN UPPER JET SEGMENT APPROACHES AND OUR REGION SHOULD BE IN THE LEFT EXIT REGION OF THE UPPER JET SEGMENT THROUGH THE EVENING AND MONDAY NIGHT. THERE COULD BE SOME CONVECTIVE DEBRIS OVER THE REGION ALONG WITH SOME CLOUDINESS JUST DUE TO THE INCREASING LOW LEVEL MOISTURE...SO SCATTERED VARIABLE BROKEN CLOUDS SHOULD BE THE RULE MONDAY...BUT WITH BOUNDARY LAYER TEMPERATURES WARMING AND DECENT MIXING...HIGH TEMPERATURES SHOULD BE WELL INTO THE 80S...NEAR 90 WARMER AREAS. CONVECTION SHOULD INITIATE WEST AND NORTH OF THE REGION...THEN INCREASE IN COVERAGE THROUGH THE AFTERNOON WITHIN THE PRE FRONTAL TROUGH AND MOVE EAST THROUGH THE EVENING. BASED ON THE PROJECTED INSTABILITY AND SHEAR...ADDED GUSTY WINDS AND SMALL HAIL IN THE WORDING AS SOME STORMS COULD BE QUITE STRONG...AND SEVERE POTENTIAL SHOULD BE CLEARER WITH NEW DATA AND GUIDANCE OVERNIGHT AND TOMORROW MORNING. THE ACTUAL SURFACE DEW POINT BOUNDARY AND BOUNDARY LAYER THERMAL GRADIENT ARE NOT FORECASTED TO TRACK THROUGH OUR REGION UNTIL TOMORROW. SO...KEEPING SCATTERED TO ISOLATED ACTIVITY THROUGH MONDAY NIGHT AND AT LEAST PART OF TUESDAY. SINCE NO REAL COOLING OR DRYING IS EXPECTED UNTIL TUESDAY AND TUESDAY NIGHT...LOWS MONDAY NIGHT SHOULD BE A BIT SULTRY...IN THE 60S TO NEAR 70. COLD ADVECTION SPREADS THROUGH THE REGION THROUGH THE DAY TUESDAY...SO PERIODS OF CLOUDS AND SUN...WITH INCREASING SUN LATER IN THE DAY. HIGHS TUESDAY IN THE 80S...BUT SOME 70S IN THE SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY AS THOSE AREAS WILL SEE THE COLD ADVECTION FIRST. THERE ARE SOME INDICATIONS THAT THE BOUNDARY LAYER WINDS COULD STAY QUITE STRONG THROUGH TUESDAY NIGHT...WHICH COULD PREVENT MANY AREAS FROM GOING CALM TUESDAY NIGHT...SO LOWS MAY NOT BE A COL AS THEY COULD BE. LOWS TUESDAY NIGHT IN THE 50S TO NEAR 60...NEAR 50 IN THE SOUTHERN ADIRONDACKS. HIGHS WEDNESDAY SHOULD BE IN THE 70S TO LOWER 80S WITH SUNNY AND DRY CONDITIONS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... WED NT...HIGH PRESSURE RIDGE QUICKLY SLIDES E...OFF EAST COAST. A DEVELOPING LIGHT S/SW LOW LEVEL FLOW...AND SOME INCREASING CLOUDS SHOULD ALLOW FOR RELATIVELY MILD TEMPS...GENERALLY FALLING INTO THE 55-60 RANGE WITHIN THE HUDSON/MOHAWK RIVER VALLEYS...AND 50-55 ACROSS HIGHER ELEVATIONS ACROSS THE NORTH COUNTRY AND WESTERN NEW ENGLAND. THU-FRI NT...LONG RANGE MODELS CONTINUE TO ADVERTISE A POTENTIALLY UNSETTLED PERIOD DURING THIS TIME FRAME...ALTHOUGH CONSIDERABLE TIMING DIFFERENCES EXIST. THE 12Z/22 GFS...AND MAJORITY OF GEFS MEMBERS INDICATE THE BEST POTENTIAL FOR WIDESPREAD SHOWERS OR PERHAPS A PERIOD OF STEADY RAIN WOULD BE THU INTO THU NT...WITH THE BEST CHC ACROSS CENTRAL AND SOUTHERN AREAS. ON THE OTHER HAND...THE 12Z/22 ECMWF DEPICTS TWO POTENTIAL WAVES OF SHOWERS/RAIN...THE FIRST MAINLY ACROSS CENTRAL AND SOUTHERN AREAS THURSDAY...THEN A MORE WIDESPREAD RAINFALL FOR FRI. GIVEN THAT WE ARE IN A RATHER DRY SPELL...IT WILL BE INTERESTING TO SEE IF EITHER OF THESE POTENTIAL SYSTEMS ACTUALLY PRODUCE BENEFICIAL RAINFALL ACROSS THE REGION...AS IT IS POSSIBLE THE BULK OF MOISTURE REMAINS SOUTH OF THE REGION. FOR NOW...HAVE INDICATED CHC POPS FOR THU-FRI...HIGHEST ACROSS CENTRAL AND SOUTHERN AREAS. GIVEN THE POSSIBILITY OF CLOUDS AND SOME RAIN...HAVE INDICATED BELOW NORMAL MAX TEMPS...GENERALLY IN THE 75-80 RANGE IN VALLEYS...AND 70-75 ACROSS HIGHER ELEVATIONS...ALTHOUGH EVEN COOLER MAXES WOULD BE POSSIBLE IF A MORE WIDESPREAD RAINFALL OCCURS. FOR OVERNIGHT MINS...EXPECT MAINLY 60-65 IN VALLEYS...AND 55-60 ACROSS HIGHER ELEVATIONS. SAT-SUN...BOTH THE 12Z/22 GFS...GEFS...AND ECMWF INDICATE AN UPPER LEVEL TROUGH POTENTIALLY IMPACTING THE REGION DURING THIS TIME FRAME...WITH THE POSSIBILITY FOR SCATTERED...MAINLY DIURNALLY DRIVEN SHOWERS AND PERHAPS SOME THUNDER...AND THEREFORE HAVE MAINTAINED CHC POPS. EXPECT MAX TEMPS TO REACH THE 80-85 RANGE IN VALLEYS...AND MAINLY 75-80 ACROSS HIGHER ELEVATIONS...ALTHOUGH AGAIN...SLIGHTLY COOLER MAX TEMPS ARE POSSIBLE SHOULD SHOWERS BE MORE WIDESPREAD. OVERNIGHT MINS SHOULD FALL INTO THE 60-65 RANGE IN VALLEYS...AND 55-60 RANGE ACROSS HIGHER ELEVATION ACROSS THE NORTH COUNTRY...AND WITHIN WESTERN NEW ENGLAND. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... EXCEPT DURING POSSIBILE CONVECTION...EXPECT MAINLY VFR CONDITIONS AT THE KALB/KGFL/KPOU/KPSF TAF SITES FOR THE TAF PERIOD ENDING AT 06Z TUESDAY. CURRENTLY...AS OF 0545Z...A LARGE CLUSTER OF TSTMS WAS MOVING JUST SOUTH OF DUE EAST ACROSS THE CENTRAL AND SOUTHERN CATSKILLS. THIS CLUSTER WILL LIKELY AFFECT THE KPOU TAF SITE BETWEEN 07Z AND 11Z AND HAVE INCLUDED A TEMPO GROUP FOR THIS TO OCCUR WITH MVFR CONDITIONS...BUT IF THE CORE OF A PARTICULAR TSTM WHERE TO GO DIRECTLY OVER KPOU...IFR CIGS/VSBYS WOULD BE POSSIBLE. NO ORGANIZED AREA OF CONVECTION HEADING TOWARDS THE OTHER TAF SITES SO WILL ONLY INCLUDE VCSH FOR NOW AND UPDATE IF ANY OTHER CONVECTION POPS UP. WITH A DECENT SOUTHERLY FLOW AT ALL THE TAF SITES EARLY THIS MORNING...NO FOG ISSUES ARE EXPECTED. DURING THE DAY...MAINLY VFR CONDITIONS WILL CONTINUE...BUT THE PASSING OF AN UPPER LEVEL TROF COULD RESULT IN AN ORGANIZED AREA OF CONVECTION AFFECTING THE REGION LATE THIS AFTERNOON AND EVENING. FOR NOW WILL FORECAST VCSH IN THE TAFS...WITH A 6 HOUR PROB 30 GROUP FOR STRONG CONVECTION WITH MVFR CIGS/VSBYS BETWEEN 23/19Z AND 24/01Z... EXCEPT BETWEEN 23/20Z AND 24/02Z AT KPSF. IFR CONDITIONS ARE ALSO POSSIBLE IF A STORM HITS ANY OF THE TAF SITES. SURFACE WINDS OUTSIDE OF TSTMS WILL GENERALLY BE SOUTH OR SOUTHWEST AT 5 TO 10 KTS WITH SOME GUSTS TO 15 KTS POSSIBLE. WIND GUSTS TO 30 KTS OR MORE ARE POSSIBLE THIS AFTERNOON AND EVENING. OUTLOOK... LATE MON NGT-TUE...MAINLY VFR. CHC SHRA/TSRA. WED...VFR. NO SIG WX. THU-FRI...VFR/MVFR. CHC SHRA/TSRA. && .FIRE WEATHER... A DISTURBANCE AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS ON MONDAY INTO MONDAY NIGHT. CANADIAN HIGH PRESSURE WILL BUILD TOWARD THE REGION TUESDAY AND CONTROL OUR WEATHER THROUGH MID WEEK. NORMAL RECOVERY OF RELATIVE HUMIDITIES TONIGHT ALTHOUGH A SOUTHERLY BREEZE AROUND 5 MPH MIGHT LIMIT DEW IN SOME OF THE HIGHER ELEVATIONS. BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS ON MONDAY INTO MONDAY NIGHT AS A SERIES OF FRONTS HEADS OUR WAY. RH VALUES LOOK TO REMAIN ELEVATED...STARTING OUT 75-90 PERCENT AND ONLY DROPPING TO THE 50 TO 60 PERCENT RANGE. THE SHOWER AND THUNDERSTORM THREAT INCREASES. IT IS A PRETTY GOOD BET MANY AREAS WILL RECEIVE AN AVERAGE OF A QUARTER INCH OR MORE THROUGH THIS TIME FRAME. TUESDAY LOOKS LIKE A MAINLY DRY DAY WITH A GUSTY WESTERLY BREEZE...10 TO 20 MPH...GUSTING AS HIGH AS 30 MPH MOHAWK VALLEY AND HIGHER ELEVATIONS. A SECONDARY COLD FRONT COULD BRING AN ADDITIONAL SHOWER OR THUNDERSTORM ON AN ISOLATED BASIS. && .HYDROLOGY... NO HYDRO PROBLEMS ARE ANTICIPATED THROUGH MUCH OF NEXT WEEK. MOSTLY DRY WEATHER IS EXPECTED TODAY AND TONIGHT ALTHOUGH A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED OUT. MORE UNSETTLED WEATHER IS EXPECTED MONDAY INTO MONDAY AS UPPER LEVEL TROUGH PLUNGES SOUTH FROM CANADA BRINGING THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS. SOME OF THESE COULD CONTAIN LOCALLY HEAVY RAINFALL BUT A WIDESPREAD HEAVY RAIN APPEARS UNLIKELY AT THIS TIME. RIVER BASIN AVERAGES ARE EXPECTED TO BE A QUARTER TO HALF AN INCH THROUGH MONDAY WHICH WOULD NOT REALLY TRIGGER A RESPONSE TO OUR SLUGGISH RIVER LEVELS. AN ADDITIONAL SHOWER OR THUNDERSTORM IS POSSIBLE TUESDAY ON AN ISOLATED BASIS THEN DRY ON WEDNESDAY. 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/NAS NEAR TERM...HWJIV/KL SHORT TERM...NAS LONG TERM...KL AVIATION...GJM FIRE WEATHER...NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
136 AM EDT MON JUL 23 2012 .SYNOPSIS... A DISTURBANCE AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH NIGHT. CANADIAN HIGH PRESSURE WILL BUILD TOWARD THE REGION TUESDAY AND CONTROL OUR WEATHER THROUGH MID WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 130 AM...A LINE OF CONVECTION (MAINLY SHOWERS) WAS MOVING OUT OF THE NORTHERN TACONICS...NORTH TO THE SOUTHERN GREENS. ANOTHER CLUSTER OF SHOWERS AND THUNDERSTORMS WAS MOVING INTO THE CATSKILLS. THE 00Z NAM EXPANDS THIS REGION INTO AN AREA PRODUCING OVER HALF AN INCH OF RAIN OVERNIGHT FROM THE CAPITAL DISTRICT AND POINTS EASTWARD. WHILE WE BELIEVE THIS IS OVERDONE...THIS CONVECTION COULD BE PUTTING LOCALIZED CORES OF HALF AN INCH OR MORE. SO FAR...NOTHING SEVERE OR EVEN "STRONG". THESE AREAS OF SCATTERED SHOWERS/STORMS WERE THE RESULT OF WARM AIR ADVECTION...A PRE-FRONTAL TROUGH (WITH MORE OF THESE EXPECTED LATER ON MONDAY) AND PERHAPS A LOW LEVEL JET DEVELOPING. THE 00Z ALY RAOB INDICATED A CAP AROUND 20,000 SO WE ARE NOT LOOKING FOR ANYTHING TO BECOME SEVERE. THE HRRR HAS NOT DONE A GOOD JOB REPRESENTING THIS CONVECTION. WE BELIEVE THE ACTIVITY OVER THE CATSKILLS SHOULD CONTINUE TO PROPAGATE EASTWARD INTO THE AREA OF PRE-FRONTAL TROUGH. ELSEWHERE...WE WILL CONTINUE WITH SLIGHT CHANCES OF SHOWERS/THUNDERSTORMS AS THE REMAINDER OF THE REGION IS UNDERGOING WEAK ASCENT. OTHERWISE...EXPECT ANOTHER WARM AND INCREASINGLY HUMID NIGHT. WITH THE CLOUDS AND SOME WIND...TEMPS WERE STILL IN THE 70S IN SOME AREAS. HAVE THEREFORE RAISED OVERNIGHT MINS A BIT...WITH 65-70 EXPECTED IN MUCH OF THE HUDSON/MOHAWK RIVER VALLEYS...AND 60-65 ELSEWHERE. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... UPPER IMPULSE AND COLD FRONT BEGIN TO APPROACH THROUGH MONDAY...BUT BEFORE THE FRONT CAN TRACK INTO THE REGION...THERE IS SOME SUGGESTION IN GUIDANCE THAT A PRE FRONTAL TROUGH COULD FORM AHEAD OF THE FRONT IN OUR REGION MONDAY AFTERNOON AND EVENING. BOUNDARY LAYER WINDS INCREASE AND MIDLEVEL LAPSE RATES ARE STILL PREDICTED TO STEEPEN. AN UPPER JET SEGMENT APPROACHES AND OUR REGION SHOULD BE IN THE LEFT EXIT REGION OF THE UPPER JET SEGMENT THROUGH THE EVENING AND MONDAY NIGHT. THERE COULD BE SOME CONVECTIVE DEBRIS OVER THE REGION ALONG WITH SOME CLOUDINESS JUST DUE TO THE INCREASING LOW LEVEL MOISTURE...SO SCATTERED VARIABLE BROKEN CLOUDS SHOULD BE THE RULE MONDAY...BUT WITH BOUNDARY LAYER TEMPERATURES WARMING AND DECENT MIXING...HIGH TEMPERATURES SHOULD BE WELL INTO THE 80S...NEAR 90 WARMER AREAS. CONVECTION SHOULD INITIATE WEST AND NORTH OF THE REGION...THEN INCREASE IN COVERAGE THROUGH THE AFTERNOON WITHIN THE PRE FRONTAL TROUGH AND MOVE EAST THROUGH THE EVENING. BASED ON THE PROJECTED INSTABILITY AND SHEAR...ADDED GUSTY WINDS AND SMALL HAIL IN THE WORDING AS SOME STORMS COULD BE QUITE STRONG...AND SEVERE POTENTIAL SHOULD BE CLEARER WITH NEW DATA AND GUIDANCE OVERNIGHT AND TOMORROW MORNING. THE ACTUAL SURFACE DEW POINT BOUNDARY AND BOUNDARY LAYER THERMAL GRADIENT ARE NOT FORECASTED TO TRACK THROUGH OUR REGION UNTIL TOMORROW. SO...KEEPING SCATTERED TO ISOLATED ACTIVITY THROUGH MONDAY NIGHT AND AT LEAST PART OF TUESDAY. SINCE NO REAL COOLING OR DRYING IS EXPECTED UNTIL TUESDAY AND TUESDAY NIGHT...LOWS MONDAY NIGHT SHOULD BE A BIT SULTRY...IN THE 60S TO NEAR 70. COLD ADVECTION SPREADS THROUGH THE REGION THROUGH THE DAY TUESDAY...SO PERIODS OF CLOUDS AND SUN...WITH INCREASING SUN LATER IN THE DAY. HIGHS TUESDAY IN THE 80S...BUT SOME 70S IN THE SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY AS THOSE AREAS WILL SEE THE COLD ADVECTION FIRST. THERE ARE SOME INDICATIONS THAT THE BOUNDARY LAYER WINDS COULD STAY QUITE STRONG THROUGH TUESDAY NIGHT...WHICH COULD PREVENT MANY AREAS FROM GOING CALM TUESDAY NIGHT...SO LOWS MAY NOT BE A COL AS THEY COULD BE. LOWS TUESDAY NIGHT IN THE 50S TO NEAR 60...NEAR 50 IN THE SOUTHERN ADIRONDACKS. HIGHS WEDNESDAY SHOULD BE IN THE 70S TO LOWER 80S WITH SUNNY AND DRY CONDITIONS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... WED NT...HIGH PRESSURE RIDGE QUICKLY SLIDES E...OFF EAST COAST. A DEVELOPING LIGHT S/SW LOW LEVEL FLOW...AND SOME INCREASING CLOUDS SHOULD ALLOW FOR RELATIVELY MILD TEMPS...GENERALLY FALLING INTO THE 55-60 RANGE WITHIN THE HUDSON/MOHAWK RIVER VALLEYS...AND 50-55 ACROSS HIGHER ELEVATIONS ACROSS THE NORTH COUNTRY AND WESTERN NEW ENGLAND. THU-FRI NT...LONG RANGE MODELS CONTINUE TO ADVERTISE A POTENTIALLY UNSETTLED PERIOD DURING THIS TIME FRAME...ALTHOUGH CONSIDERABLE TIMING DIFFERENCES EXIST. THE 12Z/22 GFS...AND MAJORITY OF GEFS MEMBERS INDICATE THE BEST POTENTIAL FOR WIDESPREAD SHOWERS OR PERHAPS A PERIOD OF STEADY RAIN WOULD BE THU INTO THU NT...WITH THE BEST CHC ACROSS CENTRAL AND SOUTHERN AREAS. ON THE OTHER HAND...THE 12Z/22 ECMWF DEPICTS TWO POTENTIAL WAVES OF SHOWERS/RAIN...THE FIRST MAINLY ACROSS CENTRAL AND SOUTHERN AREAS THURSDAY...THEN A MORE WIDESPREAD RAINFALL FOR FRI. GIVEN THAT WE ARE IN A RATHER DRY SPELL...IT WILL BE INTERESTING TO SEE IF EITHER OF THESE POTENTIAL SYSTEMS ACTUALLY PRODUCE BENEFICIAL RAINFALL ACROSS THE REGION...AS IT IS POSSIBLE THE BULK OF MOISTURE REMAINS SOUTH OF THE REGION. FOR NOW...HAVE INDICATED CHC POPS FOR THU-FRI...HIGHEST ACROSS CENTRAL AND SOUTHERN AREAS. GIVEN THE POSSIBILITY OF CLOUDS AND SOME RAIN...HAVE INDICATED BELOW NORMAL MAX TEMPS...GENERALLY IN THE 75-80 RANGE IN VALLEYS...AND 70-75 ACROSS HIGHER ELEVATIONS...ALTHOUGH EVEN COOLER MAXES WOULD BE POSSIBLE IF A MORE WIDESPREAD RAINFALL OCCURS. FOR OVERNIGHT MINS...EXPECT MAINLY 60-65 IN VALLEYS...AND 55-60 ACROSS HIGHER ELEVATIONS. SAT-SUN...BOTH THE 12Z/22 GFS...GEFS...AND ECMWF INDICATE AN UPPER LEVEL TROUGH POTENTIALLY IMPACTING THE REGION DURING THIS TIME FRAME...WITH THE POSSIBILITY FOR SCATTERED...MAINLY DIURNALLY DRIVEN SHOWERS AND PERHAPS SOME THUNDER...AND THEREFORE HAVE MAINTAINED CHC POPS. EXPECT MAX TEMPS TO REACH THE 80-85 RANGE IN VALLEYS...AND MAINLY 75-80 ACROSS HIGHER ELEVATIONS...ALTHOUGH AGAIN...SLIGHTLY COOLER MAX TEMPS ARE POSSIBLE SHOULD SHOWERS BE MORE WIDESPREAD. OVERNIGHT MINS SHOULD FALL INTO THE 60-65 RANGE IN VALLEYS...AND 55-60 RANGE ACROSS HIGHER ELEVATION ACROSS THE NORTH COUNTRY...AND WITHIN WESTERN NEW ENGLAND. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS PREVAIL THIS EVENING WITH SCT-BKN CU/STRATOCU IN VFR RANGE. CLOUDS WILL THICKEN SOMEWHAT THROUGH THIS EVENING AS A WEAK DISTURBANCE APPROACHES. IT APPEARS THAT IT WILL REMAIN TOO STABLE AT THE TERMINALS FOR ANY CONVECTION TO DEVELOP. HOWEVER THERE IS A SLIGHT CHANCE FOR SOME BRIEF SHOWERS OVERNIGHT AND WILL PLACE A VCSH AT ALL TERMINALS AFTER 07Z. THERE COULD BE SOME LIGHT FOG ESPECIALLY AT KGFL/KPSF OVERNIGHT...BUT THERE SHOULD BE ENOUGH CLOUD COVER TO PRECLUDE THICKER FOG FORMATION. WILL MENTION MVFR VSBY AT THESE TWO SITES FOR NOW. AFTER A QUIET PERIOD MONDAY MORNING...THERE WILL BE A BETTER CHANCE FOR SCATTERED THUNDERSTORMS MONDAY AFTERNOON AS A PRE-FRONTAL TROUGH MOVES ACROSS THE AREA. WILL BEGIN PROB30 FOR THUNDER AT 18Z AT ALL TAF SITES TO ADDRESS CONVECTIVE POTENTIAL. EXPECT SOUTH WINDS TO PERSIST AT KALB OVERNIGHT AT 5-10 KT...WITH A FEW GUSTS IN THE 10-15 KT RANGE POSSIBLE EARLY. ELSEWHERE...LIGHT SOUTH TO SOUTHEAST WINDS SHOULD DECREASE TO LESS THAN 5 KT OVERNIGHT. ON MONDAY...EXPECT SOUTH TO SOUTHWEST WINDS TO INCREASE TO 5-10 KT...ALTHOUGH AT KALB...FUNNELING EFFECTS UP THE HUDSON RIVER VALLEY MAY ALLOW FOR SLIGHTLY STRONGER SOUTH WINDS AT 10-15 KT...WITH PERHAPS A FEW GUSTS OF 20-25 KT AT TIMES IN THE AFTERNOON. WINDS WILL BE MUCH STRONGER...AND VARIABLE IN DIRECTION IN AND NEAR ANY THUNDERSTORMS. OUTLOOK... MON NGT-TUE...MAINLY VFR. CHC SHRA/TSRA. WED...VFR. NO SIG WX. THU-FRI...VFR/MVFR. CHC SHRA/TSRA. && .FIRE WEATHER... A DISTURBANCE AND ITS ASSOCIATED FRONTAL BOUNDARIES WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS ON MONDAY INTO MONDAY NIGHT. CANADIAN HIGH PRESSURE WILL BUILD TOWARD THE REGION TUESDAY AND CONTROL OUR WEATHER THROUGH MID WEEK. NORMAL RECOVERY OF RELATIVE HUMIDITIES TONIGHT ALTHOUGH A SOUTHERLY BREEZE AROUND 5 MPH MIGHT LIMIT DEW IN SOME OF THE HIGHER ELEVATIONS. BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS ON MONDAY INTO MONDAY NIGHT AS A SERIES OF FRONTS HEADS OUR WAY. RH VALUES LOOK TO REMAIN ELEVATED...STARTING OUT 75-90 PERCENT AND ONLY DROPPING TO THE 50 TO 60 PERCENT RANGE. THE SHOWER AND THUNDERSTORM THREAT INCREASES. IT IS A PRETTY GOOD BET MANY AREAS WILL RECEIVE AN AVERAGE OF A QUARTER INCH OR MORE THROUGH THIS TIME FRAME. TUESDAY LOOKS LIKE A MAINLY DRY DAY WITH A GUSTY WESTERLY BREEZE...10 TO 20 MPH...GUSTING AS HIGH AS 30 MPH MOHAWK VALLEY AND HIGHER ELEVATIONS. A SECONDARY COLD FRONT COULD BRING AN ADDITIONAL SHOWER OR THUNDERSTORM ON AN ISOLATED BASIS. && .HYDROLOGY... NO HYDRO PROBLEMS ARE ANTICIPATED THROUGH MUCH OF NEXT WEEK. MOSTLY DRY WEATHER IS EXPECTED TODAY AND TONIGHT ALTHOUGH A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED OUT. MORE UNSETTLED WEATHER IS EXPECTED MONDAY INTO MONDAY AS UPPER LEVEL TROUGH PLUNGES SOUTH FROM CANADA BRINGING THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS. SOME OF THESE COULD CONTAIN LOCALLY HEAVY RAINFALL BUT A WIDESPREAD HEAVY RAIN APPEARS UNLIKELY AT THIS TIME. RIVER BASIN AVERAGES ARE EXPECTED TO BE A QUARTER TO HALF AN INCH THROUGH MONDAY WHICH WOULD NOT REALLY TRIGGER A RESPONSE TO OUR SLUGGISH RIVER LEVELS. AN ADDITIONAL SHOWER OR THUNDERSTORM IS POSSIBLE TUESDAY ON AN ISOLATED BASIS THEN DRY ON WEDNESDAY. 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/NAS NEAR TERM...HWJIV/KL SHORT TERM...NAS LONG TERM...KL AVIATION...KL/JPV FIRE WEATHER...NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 PM EDT TUE JUL 24 2012 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES WILL CROSS THE MID ATLANTIC REGION THROUGH WEDNESDAY...PRODUCING WIDESPREAD THUNDERSTORMS THIS AFTERNOON AND EVENING...AND SCATTERED STORMS WEDNESDAY. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... AS OF 1000 PM TUESDAY... THE MCS FROM EARLIER THIS EVENING IS OFFSHORE AND SOUTH OF THE CWA...WITH STRONG SUBSIDENCE AND LOW LEVEL STABILIZATION IN ITS WAKE EVIDENT IN THE 00Z KGSO/KMHX RAOBS. STABILIZATION HAS BEEN FURTHER AIDED BY A BRIEF PERIOD OF STRONGER WESTERLY FLOW BETWEEN A MESO-HIGH OVER NORTHEAST TN AND THE PIEDMONT TROUGH...WHICH APPEARS TO HAVE HELPED DROP DEWPOINTS INTO THE MID 60S OVER THE WESTERN PIEDMONT. THERE IS STILL SOME ELEVATED INSTABILITY ABOVE THE SUBSIDENCE INVERSION WITH MUCAPE LIKELY STILL AT OR ABOVE 1000 J/KG...BUT PARCELS WOULD HAVE TO LIFT FROM NEAR 800MB TO TAP THIS ENERGY. THE 850-700MB FLOW OBSERVED AT KGSO WAS IN EXCESS OF 50KT...WHICH IS HIGHER THAN ANY OTHER NEARBY SITE BUT SEEMS REASONABLE GIVEN THE INTENSITY OF THE DEPARTING MCS. NONE OF THE MODELS WERE FORECASTING SUCH A STRONG LOW LEVEL JET...BUT THE FLOW IS GENERALLY DIVERGENT AND SHOULDN CONTRIBUTE TO LIFT ON ITS OWN. THERE IS ANOTHER REMNANT MCV TRACKING SOUTHEAST ACROSS SOUTHERN OHIO...WHICH THE RUC BRINGS INTO THE NORTHWEST AROUND 09Z. WE ARE NOT COMPLETELY COMFORTABLE REMOVING POPS FROM THE FORECAST GIVEN THE AFOREMENTIONED FORCING/ELEVATED INSTABILITY AND POOR MODEL PERFORMANCE...SO WE WILL LEAVE A SLIGHT CHANCE OF A THUNDERSTORM OVER THE WESTERN CWA. CLEARING IS FINALLY OCCURRING BEHIND THE MCS...BUT THIN DEBRIS CLOUDINESS WILL DRIFT OVERHEAD AT TIMES OVERNIGHT...AND GIVEN THAT DEWPOINTS HAVE FALLEN OVER THE WESTERN PIEDMONT...WE WILL TRIM 2-3 DEGREES OFF FORECAST LOWS EVERYWHERE EXCEPT THE SOUTHEAST AREAS. WEDNESDAY... NW FLOW WITH WEAK EMBEDDED SHORT WAVES EXPECTED TO CONTINUE TOMORROW...BUT THIS FLOW WILL WEAKEN WITH A CUTOFF TROUGH MOVING E OFF THE NEW ENGLAND COAST. IN TERMS OF THE AIRMASS AND THERMODYNAMIC PROFILE...LITTLE CHANGE IS EXPECTED...ALTHOUGH THE DAY WILL START OFF WITH MORE CLOUDINESS THAN TODAY. EXPECT ADDITIONAL SCATTERED AFTERNOON/EVENING SHOWERS AND TSTMS...BUT WITH WEAKER MID/UPPER FLOW AND SHEAR...EXPECT COVERAGE TO BE REDUCED COMPARED TO TODAY. SEVERE STORM IMPACTS WILL ONCE AGAIN FAVOR DAMAGING WINDS GUSTS MORE THAN HAIL. WEDNESDAY CONVECTION EXPECTED TO END BY LATE EVENING FOLLOWED BY PARTLY CLOUDY OVERNIGHT PERIOD. HIGHS WEDNESDAY 89 NORTHWEST TO NEAR 95 SOUTHWEST...AND LOWS WEDNESDAY NIGHT 71 NORTHEAST TO NEAR 75 EXTREME SOUTH. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 1225 PM TUESDAY... MIGRATORY LOW LEVEL RIDGING MOVING EAST ACROSS THE AREA WILL PRODUCE SOUTHWEST TO WESTERLY FLOW AND INDUCE A HEAT RIDGE REFLECTED IN LOW LEVEL THICKNESSES IN EXCESS OF 1440M AND H85 TEMPS 22-24C. CORRESPONDING SURFACE HIGHS EXPECTED TO REACH UPPER 90S... POTENTIALLY SOME VERY LOW TRIPLE DIGITS. THESE ARE BELOW RECORDS FOR THE DATES...WITH THE EXCEPTION OF THU AT RDU. SEE CLIMATE SECTION BELOW. HIGH INSTABILITY WITH NO FORCING MECHANISM WILL FAVOR CLIMATOLOGICAL DIURNAL CONVECTION IN THE WESTERN PIEDMONT AND IN THE COASTAL PLAIN DUE TO DIFFERENTIAL HEATING AND SEA BREEZE PENETRATION...RESPECTIVELY. TROF APPROACHING FROM THE WEST AND AN ASSOCIATED SURFACE FRONT WILL APPROACH FROM THE NW FRIDAY. FRONTAL PASSAGE WILL BE AFTER MAX HEATING FRIDAY...WITH HIGHS REACHING UPPER 90S...AGAIN WITH POTENTIALLY A STRAY 100 DEGREE READING. WILL INCREASE THE CHANCE OF SHOWERS LATER FRIDAY NIGHT DUE TO A LITTLE QUICKER FROPA AS DEPICTED ON LATEST MODEL RUNS. MILD AND MUGGY WITH LOWS WITHIN A DEGREE OR TWO OF MIDDLE 70S BOTH NIGHTS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 1225 PM TUESDAY... MEDIUM RANGE NWP GUIDANCE IS IN GOOD AGREEMENT REGARDING THE GRADUAL ESTABLISHMENT OF A MEAN TROUGH ALOFT OVER THE EAST COAST THIS WEEKEND THROUGH EARLY NEXT WEEK. AS THIS TROF BECOMES ESTABLISHED...THE SURFACE COLD FRONT EARLY THIS WEEKEND WILL PUSH THROUGH CENTRAL NC ON SAT...WITH RELATIVELY COOLER/DRIER (AND MORE STABLE) HIGH PRESSURE BUILDING ACROSS THE APPALACHIANS SUNDAY THROUGH TUESDAY. WITH THE DRIER NORTHWEST FLOW REGIME IN PLACE...ONLY SLIGHT CHANCE POPS EXPECTED SUNDAY AND MONDAY...WHILE A POTENTIAL SHORT WAVE DIGGING INTO THE EAST COAST TROF WILL INCREASE CHANCES ON TUESDAY. HIGH TEMPERATURES WILL BE NEAR NORMAL...IN THE 90 TO 95 DEGREE RANGE SATURDAY THROUGH MONDAY...POTENTIALLY A LITTLE COOLER TUESDAY IF WE GET A REINFORCING SHORT WAVE DEEPENING THE MEAN TROF. PERSISTENCE LOWS EXPECTED THROUGH THE PERIOD...BASICALLY 70 TO 74. && .AVIATION /00Z WEDNESDAY THROUGH SATURDAY/... AS OF 8 PM TUESDAY... 24 HOUR TAF PERIOD. THE BROKEN LINE/LINE OF STRONG TO SEVERE THUNDERSTORMS HAS MOVED TO THE EAST AND SOUTH OF THE AREA THIS EVENING. OTHER THAN A SLIGHT CHANCE OF SOME LINGERING LIGHT SHOWERS THIS EVENING (VFR CONDITIONS THOUGH) EXPECTED DRY CONDITION THIS EVENING. CANNOT COMPLETELY RULE OUT A FEW ISOLATED SHOWERS/STORMS LATE TONIGHT... BUT CONFIDENCE IS WAY TOO LOW FOR ANY MENTION IN THE TAFS... ALONG WITH VERY LITTLE COVERAGE IF STORMS DO DEVELOP. WILL CONTINUE TO MENTION THE POSSIBILITY FOR MVFR VISBYS AT THE EASTERN TAF SITES... WHERE THE COVERAGE OF SHOWERS AND STORMS WAS THE GREATEST EARLIER THIS AFTERNOON/EVENING... WITH KRWI STANDING THE BEST CHANCE OF SEEING IN SUB VFR CONDITIONS. EXPECT THE COVERAGE OF SHOWERS AND STORMS TO BE LESS ON WEDNESDAY WITH WEAKER FLOW ALOFT/LESS DEFINED DISTURBANCES ALOFT. HAVE ONLY ADDED A PROB30 GROUP FOR STORMS TO THE KINT/KGSO TAFS... AS THEY APPEAR TO STAND THE HIGHEST PROBABILITY OF RECEIVING SOME SHOWERS/STORMS ON WEDNESDAY AFTERNOON... WITH CONVECTION POSSIBLY DEVELOPING IN THE HIGHER TERRAIN AND DRIFTING INTO THE WESTERN PIEDMONT LATE IN THE DAY. ANY SITE THAT DOES EXPERIENCES A DECENT SHOWER OR STORM WEDNESDAY AFTERNOON WILL LIKELY EXPERIENCE MVFR/IFR CONDITIONS. OUTLOOK: EXPECT A DAILY THREAT FOR ISOLATED TO SCATTERED CONVECTION IN THE AFTERNOON AND EVENING HOURS WITH ASSOCIATED SUB VFR CEILINGS AND VISIBILITY. IN ADDITION... THERE WILL BE A THREAT OF SUB VFR FOG AND/OR LOW STRATUS EACH MORNING.... ESPECIALLY FOR LOCATIONS THAT RECEIVE SUBSTANTIAL RAIN FROM THE PREVIOUS DAY/EVENING. OTHERWISE.... EXPECT VFR CONDITIONS WILL CONTINUE. && .CLIMATE... THE FOLLOWING ARE THE RECORD HIGH TEMPERATURES FOR THE 26TH AND 27TH: RDU GSO FAY THU (26TH): 101 IN 2005 102 IN 1914 104 IN 1940 FRI (27TH): 104 IN 1940 104 IN 1914 106 IN 1940 && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MLM NEAR TERM...NP/SMITH SHORT TERM...MLM LONG TERM...MLM AVIATION...BSD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
242 AM EDT MON JUL 23 2012 .SYNOPSIS... THE HOT AND DRY UPPER LEVEL HIGH PRESSURE OVER THE MIDWEST WILL BUILD EASTWARD TO NEAR THE APPALACHAINS THROUGH TONIGHT. AN UPPER LEVEL DISTURBANCE WILL APPROACH OUR REGION FROM THE OHIO VALLEY LATE TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 PM SUNDAY... CONVECTION HAS DWINDLED ACROSS CENTRAL NC IN THE PAST HOUR WITH ONLY A LONE SHOWER NEAR THE TRIAD AS OF 01Z. THE SURFACE COLD FRONT THAT HAS BEEN DRAPED ACROSS THE REGION THE PAST FEW DAYS IS DIFFICULT TO FIND IN THE 00Z SURFACE OBS AND A LIGHT SOUTHERLY WIND HAS DEVELOPED WHEREVER CONDITIONS HAVE NOT GONE CALM.. WATER VAPOR AND RUC 300MB VORTICITY SUGGEST ANOTHER WEAK DISTURBANCE ALOFT WILL SLIP SOUTHEAST ACROSS THE NORTHERN PORTIONS OF THE AREA OVERNIGHT...BUT WITHOUT AN APPRECIABLE LOW LEVEL TRIGGER...ANYMORE SHOWERS OR STORMS SHOULD BE VERY ISOLATED. FORECAST CONFIDENCE IN STRATUS IS MUCH LOWER TONIGHT GIVEN THAT LESS RAIN HAS FALLEN TO SUPPORT STRATUS DEVELOPING IN-SITU...AND THE RETURN FLOW AROUND THE BERMUDA HIGH WILL BE WEAK. HRRR CEILING FORECASTS AND NAM/GFS BUFR SOUNDINGS SHOW BETTER POTENTIAL IN THE EAST...BUT IT COULD STILL BE PATCHY EVEN THERE. OTHERWISE..SOME PATCHY FOG AND LOWS IN THE LOWER 70S. SIMILAR CONDITIONS TO RECENT DAYS CONTINUE MONDAY...WITH ONE DIFFERENCE EXPECTED TO BE THAT THE WEAK SURFACE BOUNDARY SHOULD EITHER BE ESSENTIALLY WASHED OUT AND/OR LIFTING NORTH. WITH THE 850MB THETA-E ADVECTION EXPECTED OVERNIGHT...A RELATIVE MAXIMUM OF 850MB THETA-E IS FORECAST MONDAY. BOTH THE NAM AND THE GFS FORECAST A MID-LEVEL SHORTWAVE MOVING IN THE NORTHWEST FLOW ALOFT TOWARD CENTRAL NORTH CAROLINA DURING THE AFTERNOON...COINCIDENT WITH A WEAK 500MB JETLET AROUND 30KT AND WEAK DIFFLUENCE ALOFT. 1000-500MB LAPSE RATES ARE FORECAST TO BE JUST SHY OF 7C/KM...AND WHILE A STRONG SURFACE FEATURE TO HELP GENERATE DEEP CONVECTION SEEMS LACKING...THE PIEDMONT TROUGH ITSELF MAY BE SUFFICIENT TO PROVIDE SCATTERED THUNDERSTORMS IN THE AFTERNOON THROUGH THE EVENING. DOWNDRAFT CAPE IS ONCE AGAIN FORECAST TO BE LIMITED...BUT AN ISOLATED SEVERE STORM DUE TO DAMAGING WIND CANNOT BE RULED OUT. 1000-850MB THICKNESSES ARE SUPPORTIVE OF WARMER MOS GUIDANCE TEMPERATURES FOR HIGHS MONDAY...WITH A DEFINITE LEAN TOWARD THE BIASED CORRECTED MOS GUIDANCE READINGS WHICH HAVE BEEN DIFFICULT TO BEAT AT TIMES...WITH HIGHS MOSTLY 93 TO 96. OVERNIGHT MONDAY...DEEP CONVECTION SHOULD DIMINISH DIURNALLY AS LIFT DECREASES...ALONG WITH BUFR SOUNDINGS SHOWING THE AIR MASS BECOMING MORE STABLE WITH SLIGHT COLUMN WARMING ALOFT. THE NAM FORECASTS THE POTENTIAL FOR A DISTURBANCE IN THE NORTHWEST FLOW APPROACHING CENTRAL NORTH CAROLINA LATE AT NIGHT...WITH BETTER THAN MODEST UPPER-LEVEL DIVERGENCE AND ENHANCED 850MB CONVERGENCE APPROACHING CENTRAL NORTH CAROLINA FROM THE NORTHWEST LATE. THE GFS SHOWS SOMETHING SIMILAR...JUST DELAYED UNTIL AFTER MONDAY NIGHT. HOW THIS COULD EVOLVE IS CERTAINLY DIFFICULT TO DETERMINE...BUT WILL NOTE JUST A SLIGHT CHANCE OF A THUNDERSTORM MAINLY WEST AND NORTH OF THE TRIANGLE LATE AT NIGHT MONDAY. OVERNIGHT LOWS MONDAY NIGHT...WITH A TIGHTER GRADIENT AND A LITTLE MORE WIND THAN SHOULD BE THE CASE TONIGHT...A COUPLE OF DEGREES ON AVERAGE WARMER THAN TONIGHT... LOWER TO MID 70S. -DJF && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS OF 242 AM MONDAY... ...SLIGHT RISK OF SEVERE STORMS WITH DAMAGING WINDS TUESDAY AFTERNOON... ...HEAT INDICES AROUND 105 EXPECTED TUESDAY AFTERNOON... THE MODELS ARE IN GOOD AGREEMENT IN INDICATING THE INCREASE OF THE NW FLOW PATTERN OVER OUR REGION TUESDAY IN ADVANCE OF THE STRONG MID-UPPER LEVEL HEIGHT FALLS OVER THE GREAT LAKES INTO NEW ENGLAND. THIS ALLOWS THE PIEDMONT SURFACE TROUGH TO SHARPEN DURING THE AFTERNOON. THE COMBINATION OF STRONG HEATING (HIGHS REACHING THE MID TO UPPER 90S)...SURFACE TO 6 KM SHEAR EXPECTED TO REACH 25 TO 30KT... MLCAPES ON THE ORDER OF 2500 J/KG CAN BE EXPECTED ESPECIALLY ALONG AND EAST OF WHERE THE PIEDMONT TROUGH SETS UP. THE PARAMETERS SHOULD LEAD TO AN AFTERNOON AND EARLY EVENING OF FAIRLY ORGANIZED STRONG TO POTENTIALLY SEVERE THUNDERSTORMS WHERE DAMAGING WINDS TO 60 MPH WOULD BE THE MAIN THREAT. SCATTERED STORMS SHOULD ERUPT ALONG THE PIEDMONT TROUGH BY EARLY TO MID AFTERNOON... THEN TRANSLATE ESE IN A MORE WIDESPREAD NATURE LATE IN THE DAY. WE WILL CARRY POP FROM 40-50 WITH THE LOWEST IN THE NW AND HIGHEST IN THE EAST (ALONG AND EAST OF THE EXPECTED PIEDMONT TROUGH). HIGHS SHOULD REACH THE MID TO UPPER 90S WITH DEW POINTS IN THE 70-74 RANGE (UPPER 60S) NW PIEDMONT. THIS WOULD YIELD HEAT INDICES FOR SEVERAL HOURS TIME AROUND 105 IN ALL BUT THE NW. WE WILL HIGHLIGHT THIS POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK (HWO). THE SEVERE THREAT WILL ALSO BE HIGHLIGHTED IN THE HWO. A WEAKENING COLD FRONT OR ADDITIONAL CONVECTIVELY DRIVEN OUTFLOWS MAY SURGE INTO NORTHERN AND NORTHEASTERN SECTIONS TUESDAY EVENING. THIS MAY BE ACCOMPANIED BY STRONG CONVECTION AS WELL. ALL CONVECTION SHOULD DIMINISH BEFORE MIDNIGHT. LOWS 70-75 EXPECTED. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 230 AM MONDAY... THE NW FLOW RESUME ALOFT WILL CONTINUE WED-THU. HOWEVER... CENTRAL AND EASTERN NC MAY VERY WELL BE IN A SUBSIDENCE ZONE FOR A GOOD CHUCH OF WEDNESDAY BEHIND THE EXPECTED UPPER LEVEL DISTURBANCE PASSAGE LATE TUESDAY. HOWEVER... A LOW LEVEL BOUNDARY SHOULD EXIST FROM NW TO SE ACROSS THE WESTERN AND/OR SOUTHERN ZONES WHICH COULD POTENTIALLY AID IN SCATTERED CONVECTIVE DEVELOPMENT LATE IN THE DAY. THEREFORE... WE SHOULD SEE LIMITED POP WEDNESDAY AFTERNOON AND EVENING EXCEPT POSSIBLY IN THE WESTERN PIEDMONT AND/OR SANDHILLS WHERE WE WILL CARRY 30-35 POP. HIGHS 90-95 EXPECTED EXCEPT SOLID MID 90S SOUTH. THURSDAY THROUGH SUNDAY... ANOTHER STRONG UPPER DISTURBANCE MAY AFFECT THE REGION IN THE NW FLOW ALOFT DURING MAXIMUM HEATING THURSDAY. THIS COULD POTENTIALLY BRING ANOTHER ROUND OF ORGANIZED SEVERE WEATHER. WE WILL CARRY 40-50 POP AGAIN THURSDAY FOR THIS POTENTIAL. HIGHS LOWER TO MID 90S WITH LOWS IN THE LOWER TO MID 70S. FRIDAY INTO THE WEEKEND... WE SHOULD CONTINUE TO SEE HARD TO TIME DISTURBANCES IN THE NW FLOW THREATEN OUR AREA WITH CHANCES OF STRONG STORMS... MAINLY DURING THE AFTERNOON INTO THE OVERNIGHT HOURS. NO CHANGES NEEDED TO THE CURRENT FORECAST OF AROUND 30-35 POP EACH AFTERNOON AND EVENING FRI-SUN. HIGHS LOWER TO MID 90S. LOWS LOWER TO MID 70S. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 830 PM SUNDAY... 24 HOUR TAF PERIOD: ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE DECREASING IN INTENSITY AND COVERAGE THIS EVENING WITH THE LOSS OF DAYTIME HEATING. HOWEVER... WITH THE WARM/MOIST LOW LEVEL AIRMASS IN PLACE COUPLED WITH WEAK SUBTLE DISTURBANCES ALOFT POSSIBLY MOVING THROUGH THE AREA OVERNIGHT EXPECT THE THREAT FOR AT LEAST ISOLATED SHOWERS AND STORMS TO CONTINUE INTO OVERNIGHT. HOWEVER... GIVEN THE RATHER ISOLATED NATURE AND LOW CONFIDENCE WILL HANDEL ANY MENTION OF SHOWERS/STORMS IN THE TAFS WITH AMENDMENTS. MODELS/MODEL SOUNDINGS ARE NOT AS EXCITED ABOUT THE POSSIBILITY OF LOW STRATUS AND FOG FOR MONDAY MORNING. GIVEN THIS AND THE LACK OF SIGNIFICANT RAINFALL AT ANY CENTRAL NC TAF SITE... WILL CONTINUE TO SHOW ONLY SCATTERED STRATUS AND LOW END VFR VISBYS (WITH KRWI STANDING THE BEST CHANCES OF SEEING ANY SUB VFR VISBYS OVERNIGHT). ANY SUB VFR CONDITIONS THAT DEVELOP TONIGHT... WILL LIFT BY AT LEAST MID/LATE MORNING. ISOLATED TO WIDELY SCATTERED SHOWERS AND STORMS WILL AGAIN BE POSSIBLE ACROSS ALL OF CENTRAL NC ON MONDAY AFTERNOON/EVENING. LOOKING AHEAD: NORTHWEST FLOW ALOFT WILL BE IN PLACE OVER THE REGION THROUGHOUT MUCH (IF NOT ALL) OF THE UPCOMING WORK WEEK. AS A RESULT...EXPECT DAILY CHANCES FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS (MOST LIKELY AFTERNOON/EVENING) AND A POTENTIAL FOR FOG OR LOW CEILINGS DURING THE PRE-DAWN HOURS EACH MORNING. IN ADDITION MARGINAL LOW LEVEL WIND SHEAR CONDITIONS WILL BE POSSIBLE ON MONDAY NIGHT/TUESDAY MORNING AS WINDS AROUND A THOUSAND FEET OFF THE SURFACE ARE EXPECTED TO INCREASE TO AROUND 30 KTS... WITH LIGHT AND VARIABLE SURFACE WINDS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT NEAR TERM... SHORT TERM...BADGETT LONG TERM...BADGETT AVIATION...BSD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
215 AM EDT MON JUL 23 2012 .SYNOPSIS... A RIDGE OF HIGH PRESSURE WILL BUILD WEST OF THE AREA...ALLOWING UPPER LEVEL DISTURBANCES TO TRACK SOUTHEAST THROUGH THE REGION DURING THE WEEK. HOT AND HUMID CONDITIONS WILL OCCUR AS WELL. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1000 PM SUNDAY... CONVECTION HAS DWINDLED ACROSS CENTRAL NORTH CAROLINA IN THE PAST HOUR WITH ONLY A LONE SHOWER NEAR THE TRIAD AS OF 01Z. THE SURFACE COLD FRONT THAT HAS BEEN DRAPED ACROSS THE REGION THE PAST FEW DAYS IS DIFFICULT TO FIND IN THE 00Z SURFACE OBSERVATIONS AND A LIGHT SOUTHERLY WIND HAS DEVELOPED WHEREVER CONDITIONS HAVE NOT GONE CALM. WATER VAPOR AND RAP 300 MILLIBAR VORTICITY SUGGEST ANOTHER WEAK DISTURBANCE ALOFT WILL SLIP SOUTHEAST ACROSS THE NORTHERN PORTIONS OF THE AREA OVERNIGHT...BUT WITHOUT AN APPRECIABLE LOW LEVEL TRIGGER... ANY SHOWERS OR STORMS SHOULD BE VERY ISOLATED. FORECAST CONFIDENCE IN STRATUS IS MUCH LOWER TONIGHT GIVEN THAT LESS RAIN HAS FALLEN TO SUPPORT STRATUS DEVELOPING IN-SITU...AND THE RETURN FLOW AROUND THE BERMUDA HIGH WILL BE WEAK. HRRR CEILING FORECASTS AND NAM/GFS BUFR SOUNDINGS SHOW BETTER POTENTIAL IN THE EAST... BUT IT COULD STILL BE PATCHY EVEN THERE. OTHERWISE.. SOME PATCHY FOG AND LOWS IN THE LOWER 70S. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... AS OF 300 PM SUNDAY... SIMILAR CONDITIONS TO RECENT DAYS CONTINUE MONDAY...WITH ONE DIFFERENCE EXPECTED TO BE THAT THE WEAK SURFACE BOUNDARY SHOULD EITHER BE ESSENTIALLY WASHED OUT AND/OR LIFTING NORTH. WITH THE 850MB THETA-E ADVECTION EXPECTED OVERNIGHT...A RELATIVE MAXIMUM OF 850MB THETA-E IS FORECAST MONDAY. BOTH THE NAM AND THE GFS FORECAST A MID LEVEL SHORT WAVE MOVING IN THE NORTHWEST FLOW ALOFT TOWARD CENTRAL NORTH CAROLINA DURING THE AFTERNOON...COINCIDENT WITH A WEAK 500 MILLIBAR JETLET AROUND 30KT AND WEAK DIFFLUENCE ALOFT. 1000 TO 500 MILLIBAR LAPSE RATES ARE FORECAST TO BE JUST SHY OF 7C/KM...AND WHILE A STRONG SURFACE FEATURE TO HELP GENERATE DEEP CONVECTION SEEMS LACKING... THE PIEDMONT TROUGH ITSELF MAY BE SUFFICIENT TO PROVIDE SCATTERED THUNDERSTORMS IN THE AFTERNOON THROUGH THE EVENING. DOWNDRAFT CAPE IS ONCE AGAIN FORECAST TO BE LIMITED...BUT AN ISOLATED SEVERE STORM DUE TO DAMAGING WIND CANNOT BE RULED OUT. 1000 TO 850 MILLIBAR THICKNESSES ARE SUPPORTIVE OF WARMER MOS GUIDANCE TEMPERATURES FOR HIGHS MONDAY... WITH A DEFINITE LEAN TOWARD THE BIASED CORRECTED MOS GUIDANCE READINGS WHICH HAVE BEEN DIFFICULT TO BEAT AT TIMES...WITH HIGHS MOSTLY 93 TO 96. OVERNIGHT MONDAY...DEEP CONVECTION SHOULD DIMINISH DIURNALLY AS LIFT DECREASES...ALONG WITH BUFR SOUNDINGS SHOWING THE AIR MASS BECOMING MORE STABLE WITH SLIGHT COLUMN WARMING ALOFT. THE NAM FORECASTS THE POTENTIAL FOR A DISTURBANCE IN THE NORTHWEST FLOW APPROACHING CENTRAL NORTH CAROLINA LATE AT NIGHT...WITH BETTER THAN MODEST UPPER-LEVEL DIVERGENCE AND ENHANCED 850 MILLIBAR CONVERGENCE APPROACHING CENTRAL NORTH CAROLINA FROM THE NORTHWEST LATE. THE GFS SHOWS SOMETHING SIMILAR...JUST DELAYED UNTIL AFTER MONDAY NIGHT. HOW THIS COULD EVOLVE IS CERTAINLY DIFFICULT TO DETERMINE...BUT WILL NOTE JUST A SLIGHT CHANCE OF A THUNDERSTORM MAINLY WEST AND NORTH OF THE TRIANGLE LATE AT NIGHT MONDAY. OVERNIGHT LOWS MONDAY NIGHT...WITH A TIGHTER GRADIENT AND A LITTLE MORE WIND THAN SHOULD BE THE CASE TONIGHT...A COUPLE OF DEGREES ON AVERAGE WARMER THAN TONIGHT... LOWER TO MID 70S. -DJF STRONG HIGH PRESSURE IN THE MID AND UPPER LEVELS OF THE ATMOSPHERE PROJECTED TO BE CENTERED OVER THE MID SOUTH AND EXTEND NORTHWEST TO SOUTHEAST. MEANWHILE BROAD UPPER TROUGH OVER THE CANADIAN MARITIMES AND NEW ENGLAND WILL AMPLIFY AND DIG SOUTHWARD IN RESPONSE TO A SHORT WAVE CROSSING THE NORTHERN LAKES AND SOUTHERN ONTARIO. THE CIRCULATION AROUND THE UPPER RIDGE AND AMPLIFYING TROUGH WILL RESULT IN NORTHWEST FLOW ALOFT FROM THE SOUTHERN LAKES AND OHIO VALLEY INTO THE CAROLINAS. TAIL END OF THE SHORT WAVE RESPONSIBLE FOR THE AMPLIFICATION OF THE UPPER TROUGH WILL BRUSH VIRGINIA INTO NORTHEAST NORTH CAROLINA LATE TUESDAY INTO TUESDAY NIGHT. THIS FEATURE INTERACTING WITH THE AVAILABLE MOISTURE AND POTENTIAL INSTABILITY SHOULD TRIGGER AND SUSTAIN ISOLATED TO SCATTERED CONVECTION...MAINLY ACROSS THE NORTH HALF BY LATE TUESDAY AFTERNOON OR TUESDAY EVENING. EXPECT CONVECTION TO BETTER ORGANIZED WELL NORTH OF OUR NORTHERN COUNTIES (ACROSS NORTHERN VIRGINIA INTO SOUTHERN PENNSYLVANIA AS THIS REGION WILL BE ON THE SOUTH END OF MID LEVEL FLOW 40 TO 50 KNOTS). STILL...LOW LEVEL LAPSE RATES NEAR 9 DEGREES CELSIUS PER KILOMETER SUGGEST POSSIBILITY OF STRONG WIND GUSTS WITH ANY CONVECTION THAT DEVELOPS. PROXIMITY OF OUTFLOW BOUNDARIES AND AVAILABLE MOISTURE AND INSTABILITY WARRANT THE MENTION OF A SLIGHT CHANCE POP OVERNIGHT TUESDAY ACROSS THE NORTH. WEDNESDAY...A SERIES OF WEAK PERTURBATIONS IN THE NORTHWEST FLOW ALOFT COUPLED WITH A MODERATELY MOIST AND SLIGHTLY UNSTABLE AIR MASS WILL SUPPORT THE DEVELOPMENT OF SCATTERED CONVECTION... ESPECIALLY DURING THE HEAT OF THE DAY. PLAN TO MAINTAIN CHANCE POPS FROM PREVIOUS THOUGH POP MAY NEED TO BE INCREASED IN LATER FORECAST ISSUANCE ONCE IT BECOMES MORE CLEAR THE TIMING AND STRENGTH OF DISTURBANCES ALOFT AND EVIDENCE/POSITION OF ANY OUTFLOW BOUNDARIES FROM THE PREVIOUS DAY`S CONVECTION. LOW LEVEL THICKNESSES AVERAGE ABOUT 15 METERS ABOVE NORMAL... SUPPORTIVE OF AFTERNOON TEMPERATURES IN THE LOWER 90S NORTHWEST PIEDMONT TO THE MID 90S ELSEWHERE. THESE TEMPERATURES COMBINED WITH DEWPOINTS NEAR 70 TO LOWER 70S EQUATES TO HEAT INDICES 101 TO 105 OVER MOST OF THE REGION EXCLUDING THE NORTHWEST PIEDMONT. THICKNESSES LOWER A TAD WEDNESDAY THOUGH 850 MILLIBAR TEMPERATURES STILL PROJECTED TO BE CLOSE TO 20 DEGREES CELSIUS. SHADED MAXIMUM TEMPERATURES A DEGREE OR TWO LOWER FROM TUESDAY`S MAXIMUMS THOUGH POTENTIAL FOR TEMPERATURES TO BE ANOTHER 3 TO 5 DEGREES COOLER OVER THE NORTH IF LATE TONIGHT CONVECTION OCCURS AND ITS ASSOCIATED CLOUDINESS LINGERS WELL INTO WEDNESDAY MORNING. MINIMUM TEMPERATURES 70 TO 75. -WSS && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY... BROAD UPPER RIDGE WILL EXTEND ACROSS THE SOUTHEAST UNITED STATES ON THURSDAY. RESULTANT WEST FLOW OVER CENTRAL NORTH CAROLINA WILL MAINTAIN HOT CONDITIONS WITH A ONE IN THREE CHANCE OF AFTERNOON AND EVENING CONVECTION ALONG A WEAK SURFACE TROUGH OVER THE REGION. HEIGHTS LOWER FRIDAY INTO SATURDAY AS UPPER TROUGH OVER THE NORTHEAST UNITED STATES BEGINS TO AMPLIFY IN RESPONSE TO A DECENT SHORT WAVE CROSSING THE NORTHERN HIGH PLAINS INTO THE GREAT LAKES AND LOWER OHIO VALLEY. THIS MID LEVEL FEATURE SHOULD SHARPEN THE SURFACE TROUGH OVER OUR REGION. THIS IN TURN SHOULD CAUSE SLIGHTLY BETTER CONFLUENCE..AND WHEN COUPLED WITH THE AVAILABLE MOISTURE AND INSTABILITY...SHOULD TRANSLATE TO A HIGHER THREAT FOR SCATTERED CONVECTION EACH DAY. BY SUNDAY BASE OF UPPER TROUGH PROJECTED TO DRIFT EAST WHICH SHOULD RESULT IN A DECREASE IN CONVECTIVE COVERAGE. PROJECTED LOW LEVEL THICKNESSES REMAIN 10 TO AS MUCH AS 20 METERS ABOVE NORMAL...SUGGESTING MAXIMUM TEMPERATURES 3 TO 6 DEGREES ABOVE NORMAL. THIS WOULD SUPPORT MAXIMUM TEMPERATURES IN THE MID 90S FOR MOST OF CENTRAL NORTH CAROLINA THURSDAY THROUGH SUNDAY THOUGH CONVECTIVE CLOUD DEBRIS AND CONVECTION INITIATION WILL PLAY A ROLE IN DETERMINING HOW HOT IT WILL GET. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 115 AM... AN ISOLATED SHOWER POSSIBLE THROUGH THE MORNING. MVFR FOG IN THE NORTHWEST AT THIS TIME IS EXPECTED TO BE MORE WIDESPREAD ACROSS CENTRAL NORTH CAROLINA AS DAWN APPROACHES BUT QUICKLY ERODE AFTER SUNRISE. VERY LOCALIZED IFR CEILINGS DISSIPATE AFTER SUNRISE AS WELL. SCATTERED SHOWERS OR THUNDERSTORMS ADVECTING IN FROM THE NORTHWEST NEAR 4 PM AND MOSTLY LIKELY SPREADING EAST ACROSS THE VIRGINIA BORDER COUNTIES AS SUNSET APPROACHES. FURTHER SOUTH CONVECTION WILL BE WIDELY SCATTERED TO ISOLATED. CONVECTION ENDS IN THE EVENING AND A PERSISTENT LIGHT SOUTHWEST BREEZE WILL PREVENT FOG IN MOST LOCATIONS TONIGHT. NO CEILINGS BELOW 3000 FEET EXPECTED TONIGHT. NORTHWEST FLOW ALOFT WILL BE IN PLACE OVER THE REGION THROUGHOUT MUCH (IF NOT ALL) OF THE UPCOMING WORK WEEK. AS A RESULT...EXPECT DAILY CHANCES FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS (MOST LIKELY AFTERNOON/EVENING) AND A POTENTIAL FOR FOG OR LOW CEILINGS DURING THE PREDAWN HOURS EACH MORNING. IN ADDITION MARGINAL LOW LEVEL WIND SHEAR CONDITIONS WILL BE POSSIBLE MONDAY NIGHT INTO EARLY TUESDAY MORNING AS WINDS AROUND A THOUSAND FEET OFF THE SURFACE ARE EXPECTED TO INCREASE TO AROUND 30 KNOTS IN THE SOUTHEAST... 20 TO 25 KNOTS ELSEWHERE... WITH LIGHT AND VARIABLE SURFACE WINDS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ NEAR TERM...SMITH/DJF SHORT TERM...DJF/WSS LONG TERM...WSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
717 PM CDT TUE JUL 24 2012 .DISCUSSION... THE MAIN CHALLENGE WILL BE THUNDERSTORMS AND POTENTIAL SEVERE WEATHER OVERNIGHT. A WELL DEFINED SFC WARM FRONT STRETCHES FROM LOW PRESSURE SOUTH OF KPIR INTO NE SD...WITH 70 DEWPOINTS. THE 00Z KABR SOUNDING IS WELL CAPPED...SO IT APPEARS THAT BEST SEVERE THUNDERSTORM POTENTIAL MAY BE JUST TO THE NORTH IN OUR FA. THE LATEST NEAR TERM MODELS ALL DEVELOP A 30-40KT LLJ THAT SHOULD FOCUS CONVECTION INTO EASTERN ND BY 03Z...THEN MOVE AN MCS EAST INTO WC MN OVERNIGHT. GIVEN THE VERY HIGH PWATS AROUND 2 INCHES AND AMPLE INSTABILITY/SHEAR...A SEVERE MCS IS POSSIBLE. THE BEST FORCING SHOULD BE ALONG AND SOUTH OF THE INTERSTATE 94 CORRIDOR...SO WILL MENTION SEVERE HERE. THERE WILL BE MORE SYNOPTIC SCALE FORCING IN THE NORTH WITH STRONG UPPER LEVEL DIVERGENCE FROM A POWERFUL UPPER LOW IN WESTERN SASKATCHEWAN. THEREFORE...EXPECT SHOWERS AND STORMS FOR MOST AREAS OVERNIGHT...WITH THE BEST SEVERE POTENTIAL IN THE FAR SOUTH. GIVEN THE VERY HIGH FREEZING LEVELS...THE MAIN SEVERE THREAT COULD BE DAMAGING WINDS IF A SEVERE MCS CAN DEVELOP. && .AVIATION... ALL MODELS SUGGEST AREA OF SHRA/TSRA MOVING INTO REGION LATER THIS EVENING. COULD SEE MVFR/IFR CIGS/VSBY IN STRONGER STORMS. TOUGH TO PIN POINT ANY LOWER CIGS OR VSBY BUT DID MENTION VCTS INTO THE VALLEY LATER THIS EVENING AND OVERNIGHT. WINDS SHIFT TO THE NW AND INCREASE BY WED AFTERNOON. && .PREV DISCUSSION... /ISSUED 301 PM CDT TUE JUL 24 2012/ SHORT TERM... QUESTION IS RAIN OVERNIGHT. MOST AREAS NEED THE RAIN AND THIS SYSTEM LOOKS TO BRING THE BEST CHANCES FOR WIDESPREAD RAIN IN A LONG TIME. BUT AS USUAL THE EXACT DEVELOPMENT OF ANY COMPLEXES AND LOCATION IS STILL THE BIG QUESTION MARK. TWO AREAS OF FOCUS...ONE IS AREA NORTH OF THE WARM FRONT WHICH IS LOCATED NR A PIERRE- HURON- MARSHALL MN LINE AND THE OTHER IS ASSOC WITH 500 MB VORT MAX WELL DEFINED IN WATER VAPOR TO THE WEST OF BISMARCK. NOT AS CONCERNED ABOUT MONTANA LINE OF CONVECTION AS THINK THIS WILL DISSIPATE AS IT MOVES EAST AND THEN NORTHEAST. MODELS ALL HAVE TO VARYING DEGREES A TSTM COMPLEX OVER SRN OR CNTRL PARTS OF ND DEVELOPING NR BIS AREA AND MOVING EAST THIS EVENING. HPC USING GENERAL NAM/GFS BLEND HAS HEAVIEST QPF BIS-FAR THEN TOWARD PKD/BJI. GFS FARTHER NORTH AND LIKELY TOO HEAVY WITH QPF WITH CENTER MORE ALONG HIGHWAY TWO. POSITION OF WARM FRONT AND LIKELY TRACK OF VORT MAX GENERALLY EAST WOULD FAVOR HEAVIEST AXIS SOMEWHERE CLOSE TO I-94 THEN EAST INTO MINNESOTA LAKES COUNTRY. ALTHOUGH 18Z RAP HAS HEAVIEST PCPN MORE OVER GRAND FORKS....EARLIER RUNS PEGGED THE -8C SHOWALTERS WELL OVER FAR NE SD AND HEAVIEST QPF MORE OVER FARGO. SEEING THESE TWO AREAS ON RADAR ATTM THOUGH ECHOES ARE PRETTY WEAK. ONE BAND OF ELEVATED ACTIVITY KMSP AREA TO NR ABERDEEN THEN UP TO BISMARCK-DICKINSON WHERE THE VORT MAX ACTIVITY TAKES OVER. SPC MESO PAGE SHOWS 5000 J/KG NR WARM FRONT AND LITTLE CAP AS DEW PTS POOL IN THE LOW 70S TO OUR SOUTH. WOULD LIKE TO SEE A BETTER 850 MB JET TONIGHT WITH INDICATIONS OF A 35KT JET WITH BEST CONVERGENCE FARGO-PARK RAPIDS AREA. HOWEVER...IN GRIDDS WILL EXPAND LIKELY POPS NORTHWARD TO COVER MOST OF THE FCST AREA AS DO EXPECT AT LEAST SOME RAIN ALL AREAS....MOSTLY 03Z-08Z IN ND AND THEN 06Z-12Z IN NW/WCNTRL MN. PWATS OVER 2 INCHES IN SE ND INTO MN LAKES COUNTRY SO HVY RAIN THREAT THERE...BUT CONDITIONS ARE VERY DRY SO FLOODING NOT AN ISSUE OUTSIDE OF URBAN ISSUES THAT MAY DEVELOP. WEDNESDAY WILL SHOW UPPER LOW OVER MANITOBA AND A FAIRLY GOOD DRY PUSH EASTWARD THRU 18Z WITH TROUGH PASSING THRU. KEPT SOME CHC POPS IN THE ERN FCST AREA INTO THE AFTN AS DRIEST AIR MAY NOT QUITE MAKE IT THAT FAR EAST. ALSO MAINTAINED SOME LOW POPS IN THE AFTN OVER FAR NRN RRV CLOSER TO COOL POOL ALOFT. HOWEVER....LIFTED AND SHOWWALTERS INDICATE A PRETTY STABLE ENVIRONMENT IN DRY SLOT SOUTH OF UPPER LOW...SO POPS MAY BE A BIT TOO MUCH. LOOKS WARM WITH SOME AFTN CU WITH HIGHS IN THE 80S. KEPT LOW POPS WED NIGHT FOR CONFIDENCE IS THIS PERIOD FOR PRECIP IS QUITE LOW. UPPER LOW WILL DRIFT SOUTHEAST INTO NE MN AND THE GREAT LAKES REGION THU-THU NIGHT. COOL POOL ALOFT WILL DROP INTO MINNESOTA ALONG WITH LIKELY ASSOC SHOWER/THUNDERSTORM ACTIVITY...MAINLY RRV AND EASTWARD DURING THE DAY ON THURSDAY. ANY ACTIVITY WILL DIMINISH EARLY THU EVE THEN HIGH PRESSURE WILL BRING CLEARER SKY FOR OVERNIGHT THU NIGHT AND FRIDAY. LONG TERM FRI NIGHT-MON. FOLLOWING UPPER LOW PASSAGE MID LEVEL RIDGING WILL GRADUALLY BUILD THROUGH THE PERIOD. MODEL DIFFERENCES INVOLVE TIMING OF ANY SHORT WAVE ENERGY CRESTING RIDGE AND RELATED PCPN CHANCES. AT THIS POINT SATURDAY NIGHT-SUNDAY LOOKS TO FAVORED TIME FOR WAVE AND RELATED SURFACE TROUGH PASSAGE AND RAIN CHANCES. WITH RISING HEIGHTS/THICKNESS TEMPERATURES WILL GRADUALLY RISE THROUGH THE PERIOD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ DK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
301 PM CDT TUE JUL 24 2012 .SHORT TERM... QUESTION IS RAIN ONIGHT. MOST AREAS NEED THE RAIN AND THIS SYSTEM LOOKS TO BRING THE BEST CHANCES FOR WIDESPREAD RAIN IN A LONG TIME. BUT AS USUAL THE EXACT DEVELOPMENT OF ANY COMPLEXES AND LOCATION IS STILL THE BIG QUESTION MARK. TWO AREAS OF FOCUS...ONE IS AREA NORTH OF THE WARM FRONT WHICH IS LOCATED NR A PIERRE- HURON- MARSHALL MN LINE AND THE OTHER IS ASSOC WITH 500 MB VORT MAX WELL DEFINED IN WATER VAPOR TO THE WEST OF BISMARCK. NOT AS CONCERNED ABOUT MONTANA LINE OF CONVECTION AS THINK THIS WILL DISSIPATE AS IT MOVES EAST AND THEN NORTHEAST. MODELS ALL HAVE TO VARYING DEGREES A TSTM COMPLEX OVER SRN OR CNTRL PARTS OF ND DEVELOPING NR BIS AREA AND MOVING EAST THIS EVENING. HPC USING GENERAL NAM/GFS BLEND HAS HEAVIEST QPF BIS-FAR THEN TOWARD PKD/BJI. GFS FARTHER NORTH AND LIKELY TOO HEAVY WITH QPF WITH CENTER MORE ALONG HIGHWAY TWO. POSITION OF WARM FRONT AND LIKELY TRACK OF VORT MAX GENERALLY EAST WOULD FAVOR HEAVIEST AXIX SOMEWHERE CLOSE TO I-94 THEN EAST INTO MINNESOTA LAKES COUNTRY. ALTHOUGH 18Z RAP HAS HEAVIEST PCPN MORE OVER GRAND FORKS....EARLIER RUNS PEGGED THE -8C SHOWWALTES WELL OVER FAR NE SD AND HEAVIEST QPF MORE OVER FARGO. SEEING THESE TWO AREAS ON RADAR ATTM THOUGH ECHOES ARE PRETTY WEAK. ONE BAND OF ELEVATED ACTIVITY MSP AREA TO NR ABERDEEN THEN UP TO BISMARCK-DICKINSON WHERE THE VORT MAX ACTIVITY TAKES OVER. SPC MESO PAGE SHOWS 5000 J/KG NR WARM FRONT AND LITTLE CAP AS DEW PTS POOL IN THE LOW 70S TO OUR SOUTH. WOULD LIKE TO SEE A BETTER 850 MB JET TONIGHT WITH INDICATIONS OF A 35KT JET WITH BEST CONVERGENCE FARGO-PARK RAPIDS AREA. HOWEVER...IN GRIDDS WILL EXPAND LIKELY POPS NORTHWARD TO COVER MOST OF THE FCST AREA AS DO EXPECT AT LEAST SOME RAIN ALL AREAS....MOSTLY 03Z-08Z IN ND AND THEN 06Z-12Z IN NW/WCNTRL MN. PWATS OVER 2 INCHES IN SE ND INTO MN LAKES COUNTRY SO HVY RAIN THREAT THERE...BUT CONDITIONS ARE VERY DRY SO FLOODING NOT AN ISSUE OUTSIDE OF URBAN ISSUES THAT MAY DEVELOP. WEDNESDAY WILL SHOW UPPER LOW OVER MANITOBA AND A FAIRLY GOOD DRY PUSH EASTWARD THRU 18Z WITH TROUGH PASSING THRU. KEPT SOME CHC POPS IN THE ERN FCST AREA INTO THE AFTN AS DRIEST AIR MAY NOT QUITE MAKE IT THAT FAR EAST. ALSO MAINTAINED SOME LOW POPS IN THE AFTN OVER FAR NRN RRV CLOSER TO COOL POOL ALOFT. HOWEVER....LIFTED AND SHOWWALTERS INDICATE A PRETTY STABLE ENVIRONMENT IN DRY SLOT SOUTH OF UPPER LOW...SO POPS MAY BE A BIT TOO MUCH. LOOKS WARM WITH SOME AFTN CU WITH HIGHS IN THE 80S. KEPT LOW POPS WED NIGHT FOR CONFIDENCE IS THIS PERIOD FOR PRECIP IS QUITE LOW. UPPER LOW WILL DRIFT SOUTHEAST INTO NE MN AND THE GREAT LAKES REGION THU-THU NIGHT. COOL POOL ALOFT WILL DROP INTO MINNESOTA ALONG WITH LIKELY ASSOC SHOWER/THUNDERSTORM ACTIVITY...MAINLY RRV AND EASTWARD DURING THE DAY ON THURSDAY. ANY ACTIVITY WILL DIMINISH EARLY THU EVE THEN HIGH PRESSURE WILL BRING CLEARER SKY FOR OVERNIGHT THU NIGHT AND FRIDAY. .LONG TERM FRI NIGHT-MON. FOLLOWING UPPER LOW PASSAGE MID LEVEL RIDGING WILL GRADUALLY BUILD THROUGH THE PERIOD. MODEL DIFFERENCES INVOLVE TIMING OF ANY SHORT WAVE ENERGY CRESTING RIDGE AND RELATED PCPN CHANCES. AT THIS POINT SATURDAY NIGHT-SUNDAY LOOKS TO FAVORED TIME FOR WAVE AND RELATED SURFACE TROUGH PASSAGE AND RAIN CHANCES. WITH RISING HEIGHTS/THICKNESS TEMPERATURES WILL GRADUALLY RISE THROUGH THE PERIOD. && .AVIATION... OTHER THAN NARROW BAND OF MVFR CIGS BETWEEN FAR AND JMS EXPECTING VFR CIGS THROUGH EARLY EVENING. ALL MODELS SUGGEST AREA OF SHRA/TSRA MOVING INTO REGION LATER THIS EVENING. COULD SEE MVFR/IFR CIGS/VSBY IN STRONGER STORMS. TOUGH TO PIN POINT ANY LOWER CIGS OR VSBY BUT DID MENTION VCTS DVL INTO THE VALLEY LATE THIS EVENING. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE/VOELKER
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1027 PM EDT TUE JUL 24 2012 .SYNOPSIS... A COLD FRONT WILL PUSH SOUTH ACROSS THE REGION TONIGHT...BEFORE MOVING NORTHEAST ON WEDNESDAY AS A WARM FRONT. A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE GREAT LAKES ON THURSDAY...WITH ANOTHER COLD FRONT MOVING ACROSS THE OHIO VALLEY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... CONVECTION CONTINUES TO SKIRT THE NORTHEAST AND SOUTHWEST PARTS OF THE FORECAST AREA. ACTIVITY IN THE NORTH HAS JUST ABOUT DISSIPATED. BUT STORMS TO THE SOUTH ARE STILL GOING STRONG. HOWEVER IT APPEARS THAT THIS WILL CONTINUE TO PASS JUST SOUTH OF THE FORECAST AREA. THERE ARE STILL DECENT MID LEVEL LAPSE RATES AND SEVERAL MODELS DO SUGGEST THAT SOME ELEVATED CONVECTION COULD DEVELOP ACROSS THE FAR SOUTHERN ZONES OVERNIGHT...ALTHOUGH THE HRRR WHICH HANDLED THE CURRENT ACTIVITY RATHER WELL IS DRY. SO HAVE KEPT SLIGHT CHANCE POPS IN THE SOUTH. HAVE BUMPED UP FORECAST LOWS SLIGHTLY IN THE FAR SOUTH NEAR A STATIONARY BOUNDARY WHERE DEW POINTS WILL REMAIN HIGH. ELSEWHERE LOWS LOOKED REASONABLE. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... PRIMARY CONCERN FOR THE SHORT TERM IS THE HOT CONDITIONS EXPECTED IN THE SOUTHWESTERN CWA. THE FRONT WILL BEGIN MOVING NORTHEAST THROUGH THE CWA DURING THE MORNING HOURS...ALLOWING A PUSH OF VERY WARM AIR TO ENTER THE REGION. THE NORTHEAST PART OF THE CWA WILL PROBABLY BE TOO INFLUENCED BY THE FRONT (CLOUDS AND SOME SCATTERED CONVECTION) TO TAKE ADVANTAGE OF THE HEAT. IN THE SOUTHWEST...TEMPERATURES IN THE MID TO UPPER 90S ARE EXPECTED. WITH DEWPOINTS NEAR 70...HEAT INDEX VALUES RANGED FROM 100-104. THIS NECESSITATED A HEAT ADVISORY. THE FAR SOUTHWEST CORNER (OWEN/CARROLL) MAY BRIEFLY ENCROACH UPON WARNING CRITERIA (105+) DURING PEAK HEATING. THE RATHER EXTREME SOLUTION PROPOSED BY THE NAM12 (850 TEMPS UP TO 25 DEGREES C...SURFACE TEMPS OVER 100 DEGREES F) HAS SOME SUPPORT GIVEN THE WIDESPREAD 100-OR-ABOVE DEGREE TEMPS IN NORTHERN MISSOURI AND NEARBY STATES. THE FORECAST HAS BEEN TRENDED SLIGHTLY UPWARD (NECESSITATING THE ADVISORY AND EVEN BORDERLINE WARNING CONDITIONS IN THE FAR SOUTHWEST) BUT WILL NOT GO AS FAR AS THE NAM. THE ECMWF KEEPS 850 TEMPS MORE IN THE 21-22 DEGREE C RANGE...WHICH WOULD SUPPORT THE UPDATED FORECAST. && .LONG TERM /THURSDAY THROUGH TUESDAY/... THE BEGINNING OF THE LONG TERM TIME FRAME WILL START OUT DRY. DECENT SW FLOW AHEAD OF A COLD FRONT WILL ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 90S ON THURSDAY. WITH DEWPOINTS IN THE UPPER 60S TO THE LOWER 70S HEAT INDEX VALUES WILL BE AROUND 100 TO 104 DEGREES THURSDAY AFTERNOON. THUNDERSTORMS WILL BEGIN TO DEVELOP AND MOVE INTO THE AREA DURING MAINLY THE AFTERNOON AND EVENING HOURS IN ADVANCE OF THE FRONTAL BOUNDARY. SOME OF THESE STORMS MAY BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS THE PRIMARY THREATS. WILL GO AHEAD AND ADD HEAT AND SEVERE MENTION IN THE HWO FOR THURSDAY. PRECIPITATION CHANCES WILL DECREASE ACROSS THE AREA DURING THE OVERNIGHT HOURS THURSDAY NIGHT INTO FRIDAY MORNING. ANOTHER FRONTAL BOUNDARY WILL APPROACH THE AREA ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS TO THE REGION. PRECIPITATION WILL TAPER OFF ACROSS THE FA FRIDAY EVENING. HIGH PRESSURE WILL BE IN PLACE ACROSS THE AREA FOR THE WEEKEND. COOLER AND DRY CONDITIONS WILL BE AROUND FOR SATURDAY AND SUNDAY WITH HIGHS GENERALLY IN THE LOW TO MIDDLE 80S. LOW TEMPERATURES WILL BE IN THE LOW TO MIDDLE 60S. SOUTHERLY FLOW WILL BRING SLIGHTLY WARMER TEMPERATURES TO THE AREA FOR MONDAY WITH HIGHS INCREASING TO THE MIDDLE TO UPPER 80S. A DISTURBANCE WILL WORK INTO THE AREA FOR TUESDAY BRINGING SHOWERS AND THUNDERSTORMS BACK INTO THE FORECAST. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... EXPECT JUST HIGH AND PERHAPS SOME MID CLOUDS ACROSS THE REGION OVERNIGHT. CLOUDS SHOULD THIN WITH TIME AND WINDS WILL BE LIGHT EVENTUALLY VEERING TO THE EAST. THESE CONDITIONS COMBINED WITH SUFFICIENT NEAR SURFACE MOISTURE SHOULD RESULT IN MIST/HAZE DEVELOPMENT OVERNIGHT AT MOST LOCATIONS. SOME PLACES ARE EXPECTED TO FALL TO IFR LATE TONIGHT. VISIBILITY RESTRICTIONS WILL LAST INTO THE MORNING. A WARM FRONT WILL MOVE THROUGH THE REGION DURING THE DAY. CANNOT RULE OUT SOME CONVECTION ALONG IT. BUT PROBABILITY AND COVERAGE IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. BUT THIS BOUNDARY WILL CAUSE WINDS TO SHIFT TO SOUTH SOUTHWEST. OUTLOOK...THUNDERSTORMS POSSIBLE THURSDAY AFTERNOON INTO FRIDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR OHZ042-060- 061-070>072-077>081. KY...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR KYZ089>100. IN...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR INZ050-058- 059-066-073>075-080. && $$ SYNOPSIS...HATZOS NEAR TERM... SHORT TERM...HATZOS LONG TERM...NOVAK AVIATION...
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
258 PM EDT MON JUL 23 2012 .SYNOPSIS... UNSETTLED PATTERN IN NORTHWEST FLOW ALOFT THROUGH MID WEEK. COLD FRONT FRIDAY. && .NEAR TERM /THROUGH TUESDAY/... SO FAR HAVE NOT SEEN THE CLOUDS BREAKING UP OR THINNING MUCH...BUT CURRENT SATELLITE SHOWS SOME CLEARER SKIES OVER SW OHIO...WHICH SHOULD BRING SOME SUNSHINE TO OUR WESTERN MOST ZONES...INCREASING INSTABILITY AND THE CHANCE OF STRONGER STORMS FORMING THROUGH THE AFTERNOON. NORTH OF THIS AREA...CONVECTION HAS BEEN ONGOING MOST OF THE MORNING...ASSOCIATED WITH A SHORTWAVE TROUGH AND VORT MAX EXPECTED TO DROP SE THIS AFTERNOON. AS THIS FEATURE MOVES OVER THE AREA GETTING AFOREMENTIONED HEATING...IT SHOULD TAP INTO CAPE VALUES IN THE 1500J/KG RANGE...ALONG WITH 35-40 KTS OF 1000-500MB BULK SHEAR...RESULTING IN THE POTENTIAL FOR SOME STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON INTO EVENING. ONE WRENCH IN THE MACHINE COULD BE THE EXACT TRACK OF THE VORT MAX...BOTH NAM AND RAP SHOW THE BEST UPPER SUPPORT CROSSING OUR NORTHERN ZONES WHERE THE CLOUDS SHOULD REMAIN THICKER...THUS CONVECTION MAY STRUGGLE WHERE THE BEST UPPER SUPPORT PASSES. MODELS HAVE US BETWEEN UPPER DISTURBANCES SO BACKED OFF ON THE POPS SOME. PREVIOUS NAM RUNS HAD BEEN HINTING AT AN MCS OVERNIGHT...BUT 00Z HAS LOST THAT FEATURE...WILL HAVE TO WATCH FOR INDICATIONS THAT AN MCS IS DEVELOPING UPSTREAM...WHICH WOULD THEN REQUIRE POPS TO BE PUT BACK INTO THE FORECAST. ANOTHER UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND THUNDERSTORMS ON TUESDAY. AGAIN LOOKING AT AN UNSTABLE ATMOSPHERE WITH 1500-2500 J/KG CAPE POSSIBLE...AND NAM EVEN SHOWS 45+ KTS DEEP SHEAR...WITH PWAT VALUES CLIMBING ABOVE 2 INCHES. THIS WILL AGAIN BRING THE CHANCE OF STRONG TO SEVERE THUNDERSTORMS...WITH HEAVY RAIN ALSO POSSIBLE. DID NOT ISSUE FLASH FLOOD WATCH AT THIS POINT...BUT SHOULD AREAS RECEIVE SOME HEAVY RAIN WITH TODAYS CONVECTION...AND THEN LOOK TO BE IN LINE WITH TOMORROWS HIGH PWAT CONVECTION AS WELL...FLOODING WOULD BECOME A CONCERN. ONLY MADE MINOR TWEAKS TO TEMPERATURES THROUGH THE NEAR TERM. LOWERED HIGHS TODAY JUST A BIT ACROSS THE NORTH DUE TO PERSISTENT CLOUDS. TONIGHT WILL BE A WARM ONE...WITH HIGH HUMIDITIES AND LINGERING CLOUDS. HIGHS ON TUESDAY LOOKED FAIRLY GOOD...WITH NEAR 90 ACROSS THE LOWLANDS...AND 70S TO LOW 80S IN THE MOUNTAINS. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... A COLD FRONT WILL PUSH SOUTH TUESDAY NIGHT...WITH SHOWERS AND THUNDERSTORMS. NOT CONFIDENT HOW FAR FRONT WILL PUSH SOUTH. BUT THE END RESULT SHOULD BE A CONTINUED CHANCE OF STORMS ON WEDNESDAY...ESPECIALLY ACROSS THE SOUTH. THIS BOUNDARY SHOULD PUSH BACK NORTHEAST WEDNESDAY AND WEDNESDAY NIGHT. HPC 6HR QPF SUGGESTS UP TO 0.25 INCHES OF PRECIP ACROSS A LARGE PART OF THE AREA WEDNESDAY NIGHT. HOWEVER...NAM ACTUALLY INDICATES MUCH OF THE REGION WILL BE DRY...SO DID NOT GO VERY HIGH WITH POPS AS THE WARM FRONT PUSHES BACK NORTHEAST. REGION SHOULD THEN BE IN THE WARM SECTOR THURSDAY AND THURSDAY NIGHT. WITH DAYTIME HEATING...EXPECT A GOOD CHANCE OF SHOWERS AND STORMS. PREVIOUS TEMPS ARE CLOSE TO LATEST TEMP GUIDANCE...AND WILL BE USED. && .LONG TERM /FRIDAY THROUGH MONDAY/... USED HPC THINKING WITH SOME TWEAKS. A FEW SYSTEM WILL PUSH ACROSS THE REGION ON FRIDAY WITH A GOOD CHANCE OF SHOWERS AND STORMS. A COLD FRONT SHOULD THEN MOVE SOUTHEAST ON SATURDAY AND HIGH PRESSURE WILL BUILD IN FOR SATURDAY INTO SUNDAY. A WARM FRONT WILL THEN PUSH BACK TO THE NORTHEAST ON MONDAY. LATEST TEMP GUIDANCE IS VERY CLOSE TO THE PREVIOUS TEMP FORECAST FRIDAY THROUGH SUNDAY...SO VERY FEW CHANGES WERE MADE TO THE PREVIOUS NUMBERS. GUIDANCE LOOKS GOOD FOR TEMPERATURES MONDAY AND WAS USED. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... CONVECTION HAS DEVELOPED ACROSS MUCH OF THE FORECAST AREA...AND EXPECT IT TO CONTINUE UNTIL WE LOSE DAYTIME HEATING LATER THIS EVENING. HAVE HAD A MVFR DECK FLOATING AROUND...IMPACTING TAF SITES FROM TIME TO TIME...SO INCLUDED SOME MVFR CEILINGS FOR THE NEXT COUPLE HOURS AT KCRW AND KBKW...DO THINK IT WILL BE AN IN AND OUT OF MVFR TYPE THING THOUGH. OTHERWISE...FOCUS TURNS TO CONVECTION THROUGH THE AFTERNOON AND EVENING. IN GENERAL EXPECTING VFR...WITH DIPS INTO MVFR POSSIBLE IN STRONGER SHOWERS. SHOULD ANY STRONG STORMS FORM...BRIEF IFR AND GUSTY WINDS WOULD BE POSSIBLE...BUT TIMING AND LOCATION UNCERTAIN AT THIS TIME. MUCH OF THAT WILL DEPEND ON HOW MUCH SUNSHINE CAN MAKE IT INTO FORECAST AREA EARLY THIS AFTERNOON. EXPECT CONVECTION TO DECREASE TONIGHT...BUT WITH LIGHT FLOW AND LINGER CLOUDS DO NOT EXPECT FOG TO BE A WIDESPREAD ISSUE. HOWEVER...WITH VERY MOIST AIR IN PLACE...SHOULD RAIN HIT A TAF SITE...FOLLOWED BY SOME BREAKS IN THE CLOUDS LATER TONIGHT...FOG COULD BECOME AN ISSUE. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM TO HIGH. ALTERNATE SCENARIOS: PROBABILITY OF TSTMS MONDAY AFTERNOON HIGHLY DEPENDENT ON AMOUNT OF SUNSHINE. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z TUESDAY... IFR POSSIBLE IN STORMS THROUGH WEDNESDAY AFTERNOON. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/MZ NEAR TERM...MZ SHORT TERM...JSH LONG TERM...JSH AVIATION...MZ
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
706 AM EDT MON JUL 23 2012 .SYNOPSIS... A SHORT WAVE ALOFT WILL CROSS THE AREA THIS MORNING. A COLD FRONT OVER LOWER MICHIGAN WILL MOVE ACROSS THE REGION LATE TONIGHT INTO TUESDAY MORNING AND THEN HIGH PRESSURE WILL BRIEFLY BUILD IN TUESDAY NIGHT. A WARM FRONT WILL MOVE ACROSS THE REGION WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT AND THEN A COLD FRONT WILL MOVE THROUGH ON THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... PLENTY OF CLOUDS AND MAINLY SHOWERS TO START THE FORECAST...THIS IS BECAUSE OF A SHORT WAVE IN THE NORTHWEST FLOW ALOFT. ATTM SEEING A LITTLE MORE THUNDER AND WITH SOME SUN ON TOP WILL ADD THUNDER EVERYWHERE FOR THE MORNING AND EARLY AFTERNOON. NOT EXPECTING THE PRECIPITATION TO DECREASE TOO MUCH AS IT IS ASSOCIATED WITH A SHORT WAVE. THE HRRR MODEL AGREES WITH THAT TOO. THE CLOUDS AND SHOWERS WILL NOT DECREASE AS QUICKLY AS I HAD THOUGHT...WILL HAVE TO CARRY THE THREAT INTO EARLY AFTERNOON IN THE EAST. THE AIRMASS WILL BECOME CAPPED THIS AFTERNOON FROM WEST TO EAST AS WARMER AIR MOVES IN ALOFT. ATTM KEEPING THE AFTERNOON DRY OVER NORTHWEST OHIO AND PARTLY CLOUDY. NO SEVERE WEATHER IS EXPECTED THROUGH 6 PM. HIGH TEMPERATURES ARE TOUGH WITH SO MUCH CLOUDS THIS MORNING BUT THE AFTERNOON WILL HAVE SUN AND A MODERATE SOUTHWEST WINDS...SO THEY WILL WARM QUICKLY. THE NAM MOS SEEMS TOO WARM ESPECIALLY AT TOL AND FDY WITH READINGS OF 100 AND THE GFS MOS TOO COOL. USED A MIX OF GUIDANCE AND EVEN LOWERED THEM SOME DURING THE UPDATE. SINCE THE CLOUDS WILL HOLD THE TEMPERATURES DOWN THIS MORNING FOR A BIT WE SHOULD NOT REACH THE RECORD HIGHS FOR TODAY WHICH ARE IN THE UPPER 90S TO NEAR 100. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... A COLD FRONT WILL BE MOVING IN FROM THE NORTHWEST TONIGHT. MANY OF THE MODELS ARE TRYING TO KEEP THE AREA GENERALLY DRY EXCEPT FOR SOME SHOWERS AND THUNDERSTORMS OVER NORTHWEST PA. NO CONFIDENCE TO DO THAT...WILL GO CHANCE POPS EVERYWHERE. WILL NOT MENTION SEVERE IN THE ZONES/GRIDS BUT INCLUDE IN THE HAZARDOUS WEATHER OUTLOOK UNTIL CONDITIONS BECOME MORE CERTAIN. THE THREAT OF SHOWERS AND THUNDERSTORMS WILL DECREASE FROM NORTH TO SOUTH TUESDAY. WILL KEEP TUESDAY NIGHT DRY AS HIGH PRESSURE WILL BE OVER THE AREA. ON WEDNESDAY A WARM FRONT WILL BEGIN TO MOVE ACROSS THE REGION. WILL START THE CHANCE IN THE AFTERNOON OVER NORTHWEST OHIO AND THEN SPREAD IT EAST IN THE EVENING. FOR THURSDAY AND THURSDAY NIGHT THE GFS HAS THE LOW THAT IS ASSOCIATED WITH THE WARM FRONT DEEPENING OVER LOWER MICHIGAN. THIS DOESN`T SEEM CORRECT BUT NONE THE LESS SOME SHOWERS AND THUNDERSTORMS WILL OCCUR WITH THIS FEATURE. USED A BLEND OF GUIDANCE FOR THE TEMPERATURES. && .LONG TERM /FRIDAY THROUGH SUNDAY/... MODELS CONTINUE TO HAVE BOUNDARY LINGER OVER THE AREA INTO THE WEEKEND. A SERIES OF WEAK SURFACE LOWS FORECAST TO MOVE ALONG THE BOUNDARY...BUT MODELS NOT IN GOOD AGREEMENT AT ALL ON THE EXACT TIMING OF THE LOWS. FOR NOW WILL JUST KEEP CHANCE POPS GOING THROUGH SATURDAY. BOTH MODELS BUILD HIGH PRESSURE OVER THE AREA ON SUNDAY...SO WILL GO WITH A DRY FORECAST THEN. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS SHOULD CONTINUE THROUGH THE ENTIRE FORECAST PERIOD. ONLY EXCEPTION MIGHT BE A STRAY SHOWER NW OH OVERNIGHT WITH AN UPPER LEVEL SHORT WAVE. DID NOT MENTION THUNDERSTORMS IN THE TAF SINCE THE CONFIDENCE IS LOW. .OUTLOOK...NON VFR POSSIBLE IN SCATTERED SHOWERS/STORMS AT TIMES LATE MONDAY NIGHT THROUGH THURSDAY. && .MARINE... SMALL CRAFT ADVISORY FROM WILLOWICK EAST THIS AFTERNOON AND INTO THE OVERNIGHT...AS SOUTHWEST FLOW INCREASES TO 15 TO 25 KNOTS. WINDS TURN TO THE NORTHWEST BUT DIMINISH SOMEWHAT BEHIND A COLD FRONT THAT WILL MOVE ACROSS THE LAKE TONIGHT. CONDITIONS IMPROVE WEDNESDAY AS HIGH PRESSURE MOVES EAST ACROSS THE OHIO VALLEY/LOWER GREAT LAKES. LOW PRESSURE IS PROGGED TO MOVE ACROSS THE LAKE ON THURSDAY WITH THE FLOW BECOMING NORTHERLY BEHIND THE SYSTEM. N TO NE FLOW WILL CONTINUE ON FRIDAY WITH A NEARLY STATIONARY BOUNDARY SITUATED JUST SOUTH OF THE LAKE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 4 AM EDT TUESDAY FOR LEZ147>149. && $$ SYNOPSIS...KIELTYKA NEAR TERM...KIELTYKA SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...DJB MARINE...DJB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
805 AM EDT MON JUL 23 2012 .SYNOPSIS... WEST TO NORTHWEST FLOW ALOFT ALONG WITH AN APPROACHING COLD FRONT FROM THE LOWER GREAT LAKES WILL KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH TUESDAY. HIGH PRESSURE SHOULD PROVIDE FAIR AND TRANQUIL WEATHER FOR THE MIDDLE OF THE WEEK...WITH MORE UNSETTLED CONDITIONS EXPECTED TO RETURN TO THE AREA DURING THE SECOND HALF OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... MADE ONLY MINOR MODIFICATIONS TO THE PREVIOUS FCST THRU 24/00Z. THE MAIN CONCERN REMAINS SVR WX POTENTIAL...WITH NEARLY ALL OF THE CWA IN SLIGHT RISK. THE OTHER ISSUE IS THE RELIABILITY OF KCCX RADAR WHICH HAS BEEN DOWN SINCE LATE LAST EVE. THE ET/S NEED TO REPLACE A PART AND HOPEFULLY THE 88-D SHOULD BE 100 PCT OPERATIONAL BY NOON TDY BEFORE TSTMS DEVELOP. PREV DISC FROM THE OVERNIGHT SHIFT... CONVECTION HAS FINALLY APPEARED NORTH OF THE BORDER AND IS TRACKING ESE...WHICH WOULD BRING IT INTO MY FAR NERN ZONES JUST AROUND SUNRISE. OF MORE INTEREST LATER TODAY WILL BE THE POTENTIAL TO COOK UP SEVERE STORMS AS A POTENT COLD FRONT AND SHORT WAVE ALOFT APPROACH FROM THE GR LAKES. WITH THE REGION EXPECTED TO COME UNDER THE LEFT EXIT OF THE APPROACHING UPPER JET MAX...WE WILL SEE A RAPID RESPONSE IN THE LOW LEVELS WITH 30-40KT OF WSW LOW LEVEL JET BRINGING A SURGE IN WARM ADVECTION AND MOISTURE...LEADING TO A STEEPENING OF LOW-MID LEVEL LAPSE RATES AS WELL AS INCREASE IN WIND SHEAR...ESPECIALLY OVER THE NWRN 1/2 OF THE FCST AREA. SPC HAS THE REGION OUTLOOKED EXPECTING MODERATE AMOUNTS OF CAPE AND INCREASING SHEAR TO HELP SUPPORT SOME ORGANIZED STORMS AND DAMAGING WIND GUSTS. THE LATEST HRRR SHOWS A BROKEN LINE ENTERING THE FCST AREA BY EARLY-MID AFTERNOON. WE WILL REMAIN UNSTABLE INTO THE OVERNIGHT AHEAD OF THE COLD FRONT WHICH WILL LEAVE US VULNERABLE FOR ADDITIONAL SHOWERS AND STORMS...ESPECIALLY DURING THE FIRST HALF OF THE PERIOD. IT LOOKS LIKE A MUGGY WARM NIGHT WITH SIGNIFICANT DRYING HOLDING OFF UNTIL TUESDAY AT THE EARLIEST. && .SHORT TERM /TUESDAY/... SHORT RANGE OPERATIONAL GUIDANCE SHOWS SOME LINGERING LOW LEVEL TROFFING AND INSTABILITY FOR THE FIRST HALF OF TUESDAY...ESPECIALLY OVER OVER THE SRN HALF OF THE FCST AREA LEADING TO AT LEAST SOME SMALL CHANCE POPS FOR THE REGION. WITH THE MAIN FRONT OFF TO THE SOUTH ALONG WITH THE DEEPEST MOISTURE..I DOWNPLAYED THE TYPICALLY WET SREF AND LEANED CLOSER TO THE MOS POPS. LOOKS LIKE A VERY WARM DAY ONCE AGAIN WITH MOST AREAS WELL INTO THE 80S...AND SOME SOUTHERN LOCATIONS TICKLING 90. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AFTER A BRIEF DRY BREAK FOR MID WEEK...MED RANGE GUIDANCE IS IN BETTER AGREEMENT TONIGHT WITH UNSETTLED CONDITIONS RETURNING AS EARLY AS THURSDAY AS THE CENTRAL US RIDGE BRIEFLY BREAKS DOWN IN FAVOR OF AN APPROACHING SHORTWAVE THAT TURNS FLOW ALOFT SOUTHWESTERLY...RESULTING IN MOISTURE FLOODING BACK INTO THE REGION. AS A RESULT CHANCE POPS ARE BACK IN THE FCST FOR MOST OF THE EXTENDED WITH A PRETTY REDUNDANT MENTION OF SHOWERS OR STORMS RIGHT THROUGH SATURDAY. TEMPERATURES AFTER TUESDAY WILL NOT VARY MORE THAN A COUPLE OF DEGREES EITHER SIDE OF NORMAL RIGHT INTO THE WEEKEND. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... MOST OF THE STRONG STORMS HAVE BEEN ACROSS THE SOUTHERN FINGER LAKES...BUT A FEW HAVE BEEN BRUSHING THE PA BORDER. MAIN PROBLEM EARLY THIS MORNING WILL BE PATCHY FOG. LATER THIS AFTERNOON THE PROBLEM BECOMES THE POTENTIAL FOR STRONG TO SEVERE STORMS...AS THE COMBINATION OF WARM ADVECTION... STRONG HEATING...DIRECTIONAL SHEAR MAY TRIGGER STORMS...ESPECIALLY ACROSS THE NORTH. ACTIVITY MAY WORK SE INTO THE SUSQUEHANNA VLY THIS EVENING. A BREEZY DAY ON TUE...AS A STRONG JET MAX MOVES ACROSS THE AREA LATE. LEFT FOG OUT FOR TONIGHT. HIGH PRESSURE BUILDS IN FOR WED. FAST MOVING SYSTEMS WILL LIKELY BRING MORE STORMY WEATHER TO THE AREA ON THU...AND PERHAPS AGAIN LATE FRI. OUTLOOK... TUE...EARLY AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS SOUTH. WED...NO SIG WX EXPECTED. THU...SCT TSRA IMPACTS POSSIBLE. FRI...SCT TSRA IMPACTS POSSIBLE LATE. && .EQUIPMENT... RADAR IS BACK ONLINE AGAIN...AT LEAST FOR TIME BEING. ET STAFF PLAN TO REPLACE A PART THIS MORNING WITH FULL RESTORATION HOPEFULLY BY NOON TODAY. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE/STEINBUGL SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN EQUIPMENT...MARTIN/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
734 AM EDT MON JUL 23 2012 .SYNOPSIS... WEST TO NORTHWEST FLOW ALOFT ALONG WITH AN APPROACHING COLD FRONT FROM THE GREAT LAKES WILL KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH TUESDAY. HIGH PRESSURE SHOULD PROVIDE FAIR AND TRANQUIL WEATHER FOR THE MIDDLE OF THE WEEK...WITH MORE UNSETTLED CONDITIONS EXPECTED TO RETURN TO THE AREA BY WEEK`S END. && .NEAR TERM /THROUGH TONIGHT/... CONVECTION HAS FINALLY APPEARED NORTH OF THE BORDER AND IS TRACKING ESE...WHICH WOULD BRING IT INTO MY FAR NERN ZONES JUST AROUND SUNRISE. OF MORE INTEREST LATER TODAY WILL BE THE POTENTIAL TO COOK UP SEVERE STORMS AS A POTENT COLD FRONT AND SHORT WAVE ALOFT APPROACH FROM THE GR LAKES. WITH THE REGION EXPECTED TO COME UNDER THE LEFT EXIT OF THE APPROACHING UPPER JET MAX...WE WILL SEE A RAPID RESPONSE IN THE LOW LEVELS WITH 30-40KT OF WSW LOW LEVEL JET BRINGING A SURGE IN WARM ADVECTION AND MOISTURE...LEADING TO A STEEPENING OF LOW-MID LEVEL LAPSE RATES AS WELL AS INCREASE IN WIND SHEAR...ESPECIALLY OVER THE NWRN 1/2 OF THE FCST AREA. SPC HAS THE REGION OUTLOOKED EXPECTING MODERATE AMOUNTS OF CAPE AND INCREASING SHEAR TO HELP SUPPORT SOME ORGANIZED STORMS AND DAMAGING WIND GUSTS. THE LATEST HRRR SHOWS A BROKEN LINE ENTERING THE FCST AREA BY EARLY-MID AFTERNOON. WE WILL REMAIN UNSTABLE INTO THE OVERNIGHT AHEAD OF THE COLD FRONT WHICH WILL LEAVE US VULNERABLE FOR ADDITIONAL SHOWERS AND STORMS...ESPECIALLY DURING THE FIRST HALF OF THE PERIOD. IT LOOKS LIKE A MUGGY WARM NIGHT WITH SIGNIFICANT DRYING HOLDING OFF UNTIL TUESDAY AT THE EARLIEST. && .SHORT TERM /TUESDAY/... SHORT RANGE OPERATIONAL GUIDANCE SHOWS SOME LINGERING LOW LEVEL TROFFING AND INSTABILITY FOR THE FIRST HALF OF TUESDAY...ESPECIALLY OVER OVER THE SRN HALF OF THE FCST AREA LEADING TO AT LEAST SOME SMALL CHANCE POPS FOR THE REGION. WITH THE MAIN FRONT OFF TO THE SOUTH ALONG WITH THE DEEPEST MOISTURE..I DOWNPLAYED THE TYPICALLY WET SREF AND LEANED CLOSER TO THE MOS POPS. LOOKS LIKE A VERY WARM DAY ONCE AGAIN WITH MOST AREAS WELL INTO THE 80S...AND SOME SOUTHERN LOCATIONS TICKLING 90. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AFTER A BRIEF DRY BREAK FOR MID WEEK...MED RANGE GUIDANCE IS IN BETTER AGREEMENT TONIGHT WITH UNSETTLED CONDITIONS RETURNING AS EARLY AS THURSDAY AS THE CENTRAL US RIDGE BRIEFLY BREAKS DOWN IN FAVOR OF AN APPROACHING SHORTWAVE THAT TURNS FLOW ALOFT SOUTHWESTERLY...RESULTING IN MOISTURE FLOODING BACK INTO THE REGION. AS A RESULT CHANCE POPS ARE BACK IN THE FCST FOR MOST OF THE EXTENDED WITH A PRETTY REDUNDANT MENTION OF SHOWERS OR STORMS RIGHT THROUGH SATURDAY. TEMPERATURES AFTER TUESDAY WILL NOT VARY MORE THAN A COUPLE OF DEGREES EITHER SIDE OF NORMAL RIGHT INTO THE WEEKEND. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... MOST OF THE STRONG STORMS HAVE BEEN ACROSS THE SOUTHERN FINGER LAKES...BUT A FEW HAVE BEEN BRUSHING THE PA BORDER. MAIN PROBLEM EARLY THIS MORNING WILL BE PATCHY FOG. LATER THIS AFTERNOON THE PROBLEM BECOMES THE POTENTIAL FOR STRONG TO SEVERE STORMS...AS THE COMBINATION OF WARM ADVECTION... STRONG HEATING...DIRECTIONAL SHEAR MAY TRIGGER STORMS...ESPECIALLY ACROSS THE NORTH. ACTIVITY MAY WORK SE INTO THE SUSQUEHANNA VLY THIS EVENING. A BREEZY DAY ON TUE...AS A STRONG JET MAX MOVES ACROSS THE AREA LATE. LEFT FOG OUT FOR TONIGHT. HIGH PRESSURE BUILDS IN FOR WED. FAST MOVING SYSTEMS WILL LIKELY BRING MORE STORMY WEATHER TO THE AREA ON THU...AND PERHAPS AGAIN LATE FRI. OUTLOOK... TUE...EARLY AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS SOUTH. WED...NO SIG WX EXPECTED. THU...SCT TSRA IMPACTS POSSIBLE. FRI...SCT TSRA IMPACTS POSSIBLE LATE. && .EQUIPMENT... RADAR UP AGAIN...AT LEAST FOR TIME BEING. ET STAFF PLAN TO WORK ON IT MORE LATER TO SEE WHAT IS CAUSING IT TO SHUT DOWN AT TIMES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN EQUIPMENT...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
550 AM EDT MON JUL 23 2012 .SYNOPSIS... WEST TO NORTHWEST FLOW ALOFT ALONG WITH AN APPROACHING COLD FRONT FROM THE GREAT LAKES WILL KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH TUESDAY. HIGH PRESSURE SHOULD PROVIDE FAIR AND TRANQUIL WEATHER FOR THE MIDDLE OF THE WEEK...WITH MORE UNSETTLED CONDITIONS EXPECTED TO RETURN TO THE AREA BY WEEK`S END. && .NEAR TERM /THROUGH TONIGHT/... CONVECTION HAS FINALLY APPEARED NORTH OF THE BORDER AND IS TRACKING ESE...WHICH WOULD BRING IT INTO MY FAR NERN ZONES JUST AROUND SUNRISE. OF MORE INTEREST LATER TODAY WILL BE THE POTENTIAL TO COOK UP SEVERE STORMS AS A POTENT COLD FRONT AND SHORT WAVE ALOFT APPROACH FROM THE GR LAKES. WITH THE REGION EXPECTED TO COME UNDER THE LEFT EXIT OF THE APPROACHING UPPER JET MAX...WE WILL SEE A RAPID RESPONSE IN THE LOW LEVELS WITH 30-40KT OF WSW LOW LEVEL JET BRINGING A SURGE IN WARM ADVECTION AND MOISTURE...LEADING TO A STEEPENING OF LOW-MID LEVEL LAPSE RATES AS WELL AS INCREASE IN WIND SHEAR...ESPECIALLY OVER THE NWRN 1/2 OF THE FCST AREA. SPC HAS THE REGION OUTLOOKED EXPECTING MODERATE AMOUNTS OF CAPE AND INCREASING SHEAR TO HELP SUPPORT SOME ORGANIZED STORMS AND DAMAGING WIND GUSTS. THE LATEST HRRR SHOWS A BROKEN LINE ENTERING THE FCST AREA BY EARLY-MID AFTERNOON. WE WILL REMAIN UNSTABLE INTO THE OVERNIGHT AHEAD OF THE COLD FRONT WHICH WILL LEAVE US VULNERABLE FOR ADDITIONAL SHOWERS AND STORMS...ESPECIALLY DURING THE FIRST HALF OF THE PERIOD. IT LOOKS LIKE A MUGGY WARM NIGHT WITH SIGNIFICANT DRYING HOLDING OFF UNTIL TUESDAY AT THE EARLIEST. && .SHORT TERM /TUESDAY/... SHORT RANGE OPERATIONAL GUIDANCE SHOWS SOME LINGERING LOW LEVEL TROFFING AND INSTABILITY FOR THE FIRST HALF OF TUESDAY...ESPECIALLY OVER OVER THE SRN HALF OF THE FCST AREA LEADING TO AT LEAST SOME SMALL CHANCE POPS FOR THE REGION. WITH THE MAIN FRONT OFF TO THE SOUTH ALONG WITH THE DEEPEST MOISTURE..I DOWNPLAYED THE TYPICALLY WET SREF AND LEANED CLOSER TO THE MOS POPS. LOOKS LIKE A VERY WARM DAY ONCE AGAIN WITH MOST AREAS WELL INTO THE 80S...AND SOME SOUTHERN LOCATIONS TICKLING 90. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AFTER A BRIEF DRY BREAK FOR MID WEEK...MED RANGE GUIDANCE IS IN BETTER AGREEMENT TONIGHT WITH UNSETTLED CONDITIONS RETURNING AS EARLY AS THURSDAY AS THE CENTRAL US RIDGE BRIEFLY BREAKS DOWN IN FAVOR OF AN APPROACHING SHORTWAVE THAT TURNS FLOW ALOFT SOUTHWESTERLY...RESULTING IN MOISTURE FLOODING BACK INTO THE REGION. AS A RESULT CHANCE POPS ARE BACK IN THE FCST FOR MOST OF THE EXTENDED WITH A PRETTY REDUNDANT MENTION OF SHOWERS OR STORMS RIGHT THROUGH SATURDAY. TEMPERATURES AFTER TUESDAY WILL NOT VARY MORE THAN A COUPLE OF DEGREES EITHER SIDE OF NORMAL RIGHT INTO THE WEEKEND. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... AS NOTED BY THE EVENING CREW...SOME STRONG STORMS ACROSS THE SOUTHERN FINGER LAKES...BUT SO FAR MOST THE ACTIVITY IS NORTH OF CENTRAL PA. MAIN PROBLEM EARLY THIS MORNING WILL BE PATCHY FOG. LATER THIS AFTERNOON THE PROBLEM BECOMES THE POTENTIAL FOR STRONG TO SEVERE STORMS...AS THE COMBINATION OF WARM ADVECTION... STRONG HEATING...DIRECTIONAL SHEAR MAY TRIGGER STORMS...ESPECIALLY ACROSS THE NORTH. ACTIVITY MAY WORK SE INTO THE SUSQUEHANNA VLY THIS EVENING. A BREEZY DAY ON TUE...AS A STRONG JET MAX MOVES ACROSS THE AREA LATE. HIGH PRESSURE BUILDS IN FOR WED. FAST MOVING SYSTEMS WILL LIKELY BRING MORE STORMY WEATHER TO THE AREA ON THU...AND PERHAPS AGAIN LATE FRI. OUTLOOK... TUE...EARLY AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS SOUTH. WED...NO SIG WX EXPECTED. THU...SCT TSRA IMPACTS POSSIBLE. FRI...SCT TSRA IMPACTS POSSIBLE LATE. && .EQUIPMENT... RADAR IS INOP. EL TECHS WILL INVESTIGATE FIRST THING IN THE MORNING. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN EQUIPMENT...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
517 AM EDT MON JUL 23 2012 .SYNOPSIS... WEST TO NORTHWEST FLOW ALOFT ALONG WITH AN APPROACHING COLD FRONT FROM THE GREAT LAKES WILL KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH TUESDAY. HIGH PRESSURE SHOULD PROVIDE FAIR AND TRANQUIL WEATHER FOR THE MIDDLE OF THE WEEK...WITH MORE UNSETTLED CONDITIONS EXPECTED TO RETURN TO THE AREA BY WEEK`S END. && .NEAR TERM /THROUGH TONIGHT/... CONVECTION HAS FINALLY APPEARED NORTH OF THE BORDER AND IS TRACKING ESE...WHICH WOULD BRING IT INTO MY FAR NERN ZONES JUST AROUND SUNRISE. OF MORE INTEREST LATER TODAY WILL BE THE POTENTIAL TO COOK UP SEVERE STORMS AS A POTENT COLD FRONT AND SHORT WAVE ALOFT APPROACH FROM THE GR LAKES. WITH THE REGION EXPECTED TO COME UNDER THE LEFT EXIT OF THE APPROACHING UPPER JET MAX...WE WILL SEE A RAPID RESPONSE IN THE LOW LEVELS WITH 30-40KT OF WSW LOW LEVEL JET BRINGING A SURGE IN WARM ADVECTION AND MOISTURE...LEADING TO A STEEPENING OF LOW-MID LEVEL LAPSE RATES AS WELL AS INCREASE IN WIND SHEAR...ESPECIALLY OVER THE NWRN 1/2 OF THE FCST AREA. SPC HAS THE REGION OUTLOOKED EXPECTING MODERATE AMOUNTS OF CAPE AND INCREASING SHEAR TO HELP SUPPORT SOME ORGANIZED STORMS AND DAMAGING WIND GUSTS. THE LATEST HRRR SHOWS A BROKEN LINE ENTERING THE FCST AREA BY EARLY-MID AFTERNOON. WE WILL REMAIN UNSTABLE INTO THE OVERNIGHT AHEAD OF THE COLD FRONT WHICH WILL LEAVE US VULNERABLE FOR ADDITIONAL SHOWERS AND STORMS...ESPECIALLY DURING THE FIRST HALF OF THE PERIOD. IT LOOKS LIKE A MUGGY WARM NIGHT WITH SIGNIFICANT DRYING HOLDING OFF UNTIL TUESDAY AT THE EARLIEST. && .SHORT TERM /TUESDAY/... SHORT RANGE OPERATIONAL GUIDANCE SHOWS SOME LINGERING LOW LEVEL TROFFING AND INSTABILITY FOR THE FIRST HALF OF TUESDAY...ESPECIALLY OVER OVER THE SRN HALF OF THE FCST AREA LEADING TO AT LEAST SOME SMALL CHANCE POPS FOR THE REGION. WITH THE MAIN FRONT OFF TO THE SOUTH ALONG WITH THE DEEPEST MOISTURE..I DOWNPLAYED THE TYPICALLY WET SREF AND LEANED CLOSER TO THE MOS POPS. LOOKS LIKE A VERY WARM DAY ONCE AGAIN WITH MOST AREAS WELL INTO THE 80S...AND SOME SOUTHERN LOCATIONS TICKLING 90. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AFTER A BRIEF DRY BREAK FOR MID WEEK...MED RANGE GUIDANCE IS IN BETTER AGREEMENT TONIGHT WITH UNSETTLED CONDITIONS RETURNING AS EARLY AS THURSDAY AS THE CENTRAL US RIDGE BRIEFLY BREAKS DOWN IN FAVOR OF AN APPROACHING SHORTWAVE THAT TURNS FLOW ALOFT SOUTHWESTERLY...RESULTING IN MOISTURE FLOODING BACK INTO THE REGION. AS A RESULT CHANCE POPS ARE BACK IN THE FCST FOR MOST OF THE EXTENDED WITH A PRETTY REDUNDANT MENTION OF SHOWERS OR STORMS RIGHT THROUGH SATURDAY. TEMPERATURES AFTER TUESDAY WILL NOT VARY MORE THAN A COUPLE OF DEGREES EITHER SIDE OF NORMAL RIGHT INTO THE WEEKEND. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... AS NOTED BY THE EVENING CREW...SOME STRONG STORMS ACROSS THE SOUTHERN FINGER LAKES...BUT SO FAR THE ACTIVITY IS NORTH OF CENTRAL PA. MAIN PROBLEM EARLY THIS MORNING WILL BE PATCHY FOG. LATER THIS AFTERNOON THE PROBLEM BECOMES THE POTENTIAL FOR STRONG TO SEVERE STORMS...AS THE COMBINATION OF WARM ADVECTION... STRONG HEATING...DIRECTIONAL SHEAR MAY TRIGGER STORMS...ESPECIALLY ACROSS THE NORTH. ACTIVITY MAY WORK SE INTO THE SUSQUEHANNA VLY THIS EVENING. A BREEZY DAY ON TUE...AS A STRONG JET MAX MOVES ACROSS THE AREA LATE. HIGH PRESSURE BUILDS IN FOR WED. FAST MOVING SYSTEMS WILL LIKELY BRING MORE STORMY WEATHER TO THE AREA ON THU...AND PERHAPS AGAIN LATE FRI. OUTLOOK... TUE...EARLY AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS SOUTH. WED...NO SIG WX EXPECTED. THU...SCT TSRA IMPACTS POSSIBLE. FRI...SCT TSRA IMPACTS POSSIBLE LATE. && .EQUIPMENT... RADAR IS INOP. EL TECHS WILL INVESTIGATE FIRST THING IN THE MORNING. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN EQUIPMENT...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
231 AM EDT MON JUL 23 2012 .SYNOPSIS... WEST TO NORTHWEST FLOW ALOFT ALONG WITH AN APPROACHING COLD FRONT FROM THE GREAT LAKES WILL KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH TUESDAY. HIGH PRESSURE SHOULD PROVIDE FAIR AND TRANQUIL WEATHER FOR THE MIDDLE OF THE WEEK...WITH MORE UNSETTLED CONDITIONS EXPECTED TO RETURN TO THE AREA BY WEEK`S END. && .NEAR TERM /THROUGH TONIGHT/... SREF CONTINUES TOO WET FOR THE OVERNIGHT...SO HAVE LOWERED POPS BASED ON LATEST OBSERVED TRENDS. 02Z HRRR STILL WANTS TO FIRE UP AN MCS TO OUR NORTH AND TRACK IT DOWN OVER NERN AREAS BY MID MORNING. AGAIN...NO EVIDENCE OF ANYTHING HAPPENING NOW SO CONFIDENCE IN THE FUTURE OF THE HRRR IS PRETTY MUCH NIL. SO FOR THE REST OF THE OVERNIGHT...EXPECTATIONS HAVE BEEN LOWERED OVERALL. IT WILL REMAIN MILD WITH GENERALLY IN THE 65-70F RANGE. && .SHORT TERM /TUESDAY/... THE PERSISTENT UPPER RIDGE CENTERED OVR THE CENTRAL CONUS WILL SHIFT A BIT EWD ON MONDAY. ON THE NERN PERIPHERY OF THE UPPER RIDGE...A BELT OF W-NW MID-LVL FLOW IS FCST TO STRENGTHEN INTO THE NE STATES AS S/WV TROUGH AMPLIFIES OVR SERN CANADA. AGREE WITH THE OVERNIGHT MID-SHIFT FORECASTER THAT THE CONVECTIVE ENVIRONMENT FOR TOMORROW LOOKS RATHER INTERESTING...WITH INCREASING W-NWLY DEEP LYR SHEAR ATOP A MODERATELY UNSTABLE BLYR. THE WLY FLOW WILL CONT TO DRAW EML/PLUME OF VERY STEEP MID LVL LAPSE RATES EWD FM THE MIDWEST INTO THE AREA AHEAD OF APPROACHING COLD FRONT DROPPING SEWD FM THE LWR LKS. SREF DATA SHOWS H85 MSTR FLUX ANOMS PEAKING WELL ABOVE NORMAL FROM MON EVE INTO THE OVERNIGHT...PERHAPS SUGGESTING A ORGANIZED CONVECTIVE COMPLEX RACING SEWD INTO THE AREA. WHILE THE DETAILS ARE STILL SOMEWHAT UNCERTAIN...SPC HAS ALSO RECOGNIZED THE INCREASE SVR WX THREAT AND UPGRADED A GREATER PORTION OF THE CWA TO SLIGHT RISK. UPDATED THE HWO TO ACCOUNT FOR THE LARGER SLIGHT RISK THREAT AREA. MAX TEMPS WILL BE HOT WITH HIGHS AROUND 90F IN THE CENTRAL AND SRN VALLEYS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE LONG TERM WILL BE DOMINATED BY PERSISTENT RIDGE OVER THE CENTRAL U.S. - RETROGRADING SLIGHTLY WESTWARD INTO THE ROCKIES. THIS PATTERN WILL FEED NW FLOW INTO THE NERN U.S. INITIALLY WAVE IN UPPER FLOW WILL NUDGE A FRONTAL BOUNDARY INTO THE REGION FOR MON AND TUE...WITH CHANCES FOR SHOWERS/TSTMS. BEST CHANCES ON TUE APPEAR TO BE IN THE SW...AS AN MCS MAY SLIDE INTO THAT AREA LATER MON NIGHT INTO THE FIRST HALF OF TUES. AFTER THAT...CHANGE IN AIRMASS WILL BRING SOME WARM AND DRIER WX FOR MID WEEK. EARLIER DISAGREEMENTS FOR LATE WEEK BETWEEN THE OPERATIONAL GFS AND ECMWF ARE LESSER THIS CYCLE. THOUGH THERE ARE STILL DIFFS IN POSITION OF PRECIP AREAS FOR THU...BOTH MODELS GIVE CHANCE OF TSTMS FOR MAINLY NW HALF OF CWA. FRONTAL BOUNDARY PUSHES THROUGH ON FRI...WITH INCREASING CHANCES FOR SHOWERS/TSTMS. WEATHER MAY REMAIN A BIT UNSETTLED HEADING INTO SAT...BUT PRECIP CHANCES DECREASE SAT INTO SUN AS SFC HIGH BUILDS IN. TEMPS DON/T MOVE MUCH THROUGH THE PERIOD...REMAINING NEAR SEASONAL AVERAGES. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... AS NOTED BY THE EVENING CREW...SOME STRONG STORMS ACROSS THE SOUTHERN FINGER LAKES...BUT SO FAR THE ACTIVITY IS NORTH OF CENTRAL PA. MAIN PROBLEM EARLY THIS MORNING WILL BE PATCHY FOG. LATER THIS AFTERNOON THE PROBLEM BECOMES THE POTENTIAL FOR STRONG TO SEVERE STORMS...AS THE COMBINATION OF WARM ADVECTION... STRONG HEATING...DIRECTIONAL SHEAR MAY TRIGGER STORMS...ESPECIALLY ACROSS THE NORTH. ACTIVITY MAY WORK SE INTO THE SUSQUEHANNA VLY THIS EVENING. A BREEZY DAY ON TUE...AS A STRONG JET MAX MOVES ACROSS THE AREA LATE. HIGH PRESSURE BUILDS IN FOR WED. FAST MOVING SYSTEMS WILL LIKELY BRING MORE STORMY WEATHER TO THE AREA ON THU...AND PERHAPS AGAIN LATE FRI. OUTLOOK... TUE...EARLY AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS SOUTH. WED...NO SIG WX EXPECTED. THU...SCT TSRA IMPACTS POSSIBLE. FRI...SCT TSRA IMPACTS POSSIBLE LATE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
127 AM EDT MON JUL 23 2012 .SYNOPSIS... WEST TO NORTHWEST FLOW ALOFT ALONG WITH AN APPROACHING COLD FRONT FROM THE GREAT LAKES WILL KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH TUESDAY. HIGH PRESSURE SHOULD PROVIDE FAIR AND TRANQUIL WEATHER FOR THE MIDDLE OF THE WEEK...WITH MORE UNSETTLED CONDITIONS EXPECTED TO RETURN TO THE AREA BY WEEK`S END. && .NEAR TERM /THROUGH TONIGHT/... SREF CONTINUES TOO WET FOR THE OVERNIGHT...SO HAVE LOWERED POPS BASED ON LATEST OBSERVED TRENDS. 02Z HRRR STILL WANTS TO FIRE UP AN MCS TO OUR NORTH AND TRACK IT DOWN OVER NERN AREAS BY MID MORNING. AGAIN...NO EVIDENCE OF ANYTHING HAPPENING NOW SO CONFIDENCE IN THE FUTURE OF THE HRRR IS PRETTY MUCH NIL. SO FOR THE REST OF THE OVERNIGHT...EXPECTATIONS HAVE BEEN LOWERED OVERALL. IT WILL REMAIN MILD WITH GENERALLY IN THE 65-70F RANGE. && .SHORT TERM /TUESDAY/... THE PERSISTENT UPPER RIDGE CENTERED OVR THE CENTRAL CONUS WILL SHIFT A BIT EWD ON MONDAY. ON THE NERN PERIPHERY OF THE UPPER RIDGE...A BELT OF W-NW MID-LVL FLOW IS FCST TO STRENGTHEN INTO THE NE STATES AS S/WV TROUGH AMPLIFIES OVR SERN CANADA. AGREE WITH THE OVERNIGHT MID-SHIFT FORECASTER THAT THE CONVECTIVE ENVIRONMENT FOR TOMORROW LOOKS RATHER INTERESTING...WITH INCREASING W-NWLY DEEP LYR SHEAR ATOP A MODERATELY UNSTABLE BLYR. THE WLY FLOW WILL CONT TO DRAW EML/PLUME OF VERY STEEP MID LVL LAPSE RATES EWD FM THE MIDWEST INTO THE AREA AHEAD OF APPROACHING COLD FRONT DROPPING SEWD FM THE LWR LKS. SREF DATA SHOWS H85 MSTR FLUX ANOMS PEAKING WELL ABOVE NORMAL FROM MON EVE INTO THE OVERNIGHT...PERHAPS SUGGESTING A ORGANIZED CONVECTIVE COMPLEX RACING SEWD INTO THE AREA. WHILE THE DETAILS ARE STILL SOMEWHAT UNCERTAIN...SPC HAS ALSO RECOGNIZED THE INCREASE SVR WX THREAT AND UPGRADED A GREATER PORTION OF THE CWA TO SLIGHT RISK. UPDATED THE HWO TO ACCOUNT FOR THE LARGER SLIGHT RISK THREAT AREA. MAX TEMPS WILL BE HOT WITH HIGHS AROUND 90F IN THE CENTRAL AND SRN VALLEYS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE LONG TERM WILL BE DOMINATED BY PERSISTENT RIDGE OVER THE CENTRAL U.S. - RETROGRADING SLIGHTLY WESTWARD INTO THE ROCKIES. THIS PATTERN WILL FEED NW FLOW INTO THE NERN U.S. INITIALLY WAVE IN UPPER FLOW WILL NUDGE A FRONTAL BOUNDARY INTO THE REGION FOR MON AND TUE...WITH CHANCES FOR SHOWERS/TSTMS. BEST CHANCES ON TUE APPEAR TO BE IN THE SW...AS AN MCS MAY SLIDE INTO THAT AREA LATER MON NIGHT INTO THE FIRST HALF OF TUES. AFTER THAT...CHANGE IN AIRMASS WILL BRING SOME WARM AND DRIER WX FOR MID WEEK. EARLIER DISAGREEMENTS FOR LATE WEEK BETWEEN THE OPERATIONAL GFS AND ECMWF ARE LESSER THIS CYCLE. THOUGH THERE ARE STILL DIFFS IN POSITION OF PRECIP AREAS FOR THU...BOTH MODELS GIVE CHANCE OF TSTMS FOR MAINLY NW HALF OF CWA. FRONTAL BOUNDARY PUSHES THROUGH ON FRI...WITH INCREASING CHANCES FOR SHOWERS/TSTMS. WEATHER MAY REMAIN A BIT UNSETTLED HEADING INTO SAT...BUT PRECIP CHANCES DECREASE SAT INTO SUN AS SFC HIGH BUILDS IN. TEMPS DON/T MOVE MUCH THROUGH THE PERIOD...REMAINING NEAR SEASONAL AVERAGES. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... LATE EVENING RADAR MOSAIC SHOWING SCT SHRA/TSRA REMAINING NORTH OF THE PA/NY BORDER. CAN/T RULE OUT AN ISOLD SHRA OR TSRA ACROSS NORTHERN PA TONIGHT...BUT ANTICIPATED COVERAGE TOO SPARSE TO MENTION IN THE FCST AT EITHER BFD OR IPT. MCLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN AREAS OF FOG AFTER 06Z. LATEST MDL GUIDANCE AND 23Z DWPT DEPRESSIONS SUGGEST THE LOWER SUSQ VALLEY...INCLUDING MDT/LNS...ARE MOST LIKELY TO EXPERIENCE VSBY REDUCTIONS BTWN 06Z-13Z. ALTHOUGH DON/T ANTICIPATE VSBYS TO DROP BLW MVFR AT MOST LOCATIONS...LATEST MDL SFC RH FIELDS AND MOS GUIDANCE SUGGEST A BRIEF DIP BLW 3SM IS POSSIBLE AT LNS NR DAWN. A TROUGH OF LOW PRES WILL DIVE SE ACROSS THE REGION DURING THE DAYLIGHT HOURS OF MONDAY...POSSIBLY BRINGING A PERIOD OF SHRA/TSRA TO THE AREA. LATEST MDL GUIDANCE SUGGESTS THE BEST CHC OF SHRA/TSRA WILL BE SOMETIME BTWN 16Z-21Z OVER WESTERN PA AND BTWN 18Z-23Z OVER EASTERN PA. A COUPLE HRS OF MVFR CONDS COULD ACCOMPANY THE PASSAGE OF THESE POTENTIAL SHRA/TSRA. OUTLOOK... TUE...EARLY AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS SOUTH. WED...NO SIG WX EXPECTED. THU...SCT PM TSRA IMPACTS POSSIBLE. FRI...SCT TSRA IMPACTS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
237 PM EDT MON JUL 23 2012 .SYNOPSIS... A WEAK UPPER LEVEL RIDGE WILL BUILD ACROSS THE REGION AND PERSIST THROUGH THE END OPF THE WORK WEEK. A COLD FRONT IS THEN EXPECTED TO PUSH INTO THE CAROLINAS AND NORTHEAST GEORGIA LATE FRIDAY AND BECOME STATIONARY OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... SHOWERS AND THUNDERSTORMS DEVELOPING ALONG THE EASTERN ESCARPMENT OF THE BLUE RIDGE LINE UP WELL WITH THE LOCATION OF AN H5 SHORT WAVE ON THE RAP MODEL. THE FEATURE WILL QUICKLY MOVE SOUTHEASTWARD ACROSS THE REMAINDER OF THE FORECAST AREA INTO THE LATE AFTERNOON HOURS. WITH H5 WINDS OF 25 TO 30 KTS OVER THE NC ZONES AND NRN UPSTATE...THE CLUSTERS OF SHOWERS AND STORMS SHOULD SHOW SOME ORGANIZATION IN THESE AREAS. WITH DCAPE VALUES AOA 1000 J/KG...SOME AREAS OF DAMAGING WINDS ARE LIKELY. THE STORMS ARE QUITE TALL ALREADY THIS AFTN AND SOME OF THEM WILL ALSO PRODUCE CONCENTRATED AREAS OF CLOUD TO GROUND LIGHTNING STRIKES. NVA WILL DEVELOP BEHIND THE SHORT WAVE LATER THIS EVENING AND ACTIVITY SHOULD QUICKLY END BY AROUND SUNSET. LATE TONIGHT SOME ACTIVITY MAY APPROACH THE MOUNTAINS FROM THE NW. HOWEVER...A STRONG WLY ORIENTED 925 MB LLVL JET WILL STAY NORTH THE REGION AND THIS FEATURE SHOULD BE ONE OF THE MAIN DRIVERS FOR NOCTURNAL CONVECTION. THEREFORE...I THINK THE OVERNIGHT HOURS WILL LARGELY BE QUIET. A BELT OF STRONG TROPOSPHERIC WESTERLIES WILL DIVE ACROSS THE MID-ATLANTIC STATES ON TUESDAY. THERE IS A GOOD CHANCE FOR AN ORGANIZED SEVERE MCS IN THIS AREA. THE WIND SHEAR GRADUALLY DECREASES TO THE SOUTHWEST CLOSER TO THE STRONG H5 RIDGE CENTERED OVER THE MS RIVER VALLEY. DEPENDING ON THE TIMING OF THE MCS DEVELOPMENT...THE NRN ZONES MAY SEE AN AREA OF ORGANIZED CONVECTION ON TUESDAY. IN ADDITION...CONVECTIVE DEBRIS OVER THE VIRGINIAS MAY RESULT IN THE BELT OF GREATEST INSTABILITY DOWN ACROSS WRN NC AND NRN SC...WHICH WILL ALSO AID CONVECTIVE DEVELOPMENT ACROSS THE NRN AND CENTRAL PART OF THE FORECAST AREA LATER TMRW. THE LATEST SPC DAY 2 CONVECTIVE OUTLOOK HAS MOST OF THE FA UNDER A SLIGHT RISK WITH THE EXCEPTION OF THE UPPER SAVANNAH RIVER VALLEY. A MENTION OF SEVERE STORMS WILL BE ADDED TO THE DAY 2 HWO. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 230 PM EDT MONDAY...AN OLD COLD FRONT IS EXPECTED TO STALL OVER THE REGION ON WEDNESDAY MORNING...THEN BEGIN TO LIFT NE DURING THE AFTERNOON AS A WARM FRONT. AT H5...RIDGE CENTER WILL REMAIN OVER THE MISSISSIPPI RIVER VALLEY WITH NW FLOW ACROSS THE SOUTHERN APPALACHIAN REGION. FORECAST SOUNDINGS INDICATE THAT SHEAR WILL INCREASE ACROSS THE REGION ON WEDNESDAY...BULK SHEAR AROUND 20 KTS BELOW 6 KM. HIGH TEMPERATURES AROUND 5 DEGREES ABOVE NORMAL SHOULD RESULT IN MODERATE CAPE VALUES AND STEEP LLVL LAPSE RATES DURING THE AFTERNOON. SHORT RANGE MODELS INDICATE THAT AN MCS MAY TRACK ACROSS KY DURING THE MORNING...WITH REMNANT CONVECTION AND POSSIBLE MCV MOVING ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA DURING THE DAY. I WILL FORECAST POPS AROUND 50 PERCENT ACROSS THE NRN MTNS AND 40 PERCENT ACROSS THE I-40 CORRIDOR TO 30 PERCENT ACROSS THE UPPER SAVANNAH RIVER VALLEY. GIVEN THE SHEAR AND INSTABILITY...ORGANIZED MULTI-CELL STORMS WILL BE POSSIBLE. THURSDAY...MID LEVEL HEIGHTS BUILD OVER 590 DAM DURING THE DAY. LLVL SHEAR ACROSS THE REGION SHOULD WEAKEN WITH THE RETURN OF THE RIDGE. AT THE SFC...A LEE TROF IS EXPECTED TO REMAIN ACROSS THE CWA. WEAK DOWNSLOPE FLOW AND DEEP MIXING MAY RESULT IN A SLIGHT DECREASE IN DEWPOINTS DURING THE AFTERNOON...ESPECIALLY ACROSS THE NC FOOTHILLS. THE LOWER DEWPOINT SHOULD CONTRIBUTE TO HIGHER CIN VALUES. THIS PATTERN SHOULD FAVOR THE DEVELOPMENT OF RIDGETOP TSRA BY MID AFTERNOON...SPREADING EAST THROUGH EARLY EVENING. I WILL FORECAST 30 TO 40 POPS ACROSS THE MTNS WITH LOW CHC POPS EAST. HIGH TEMPERATURES SHOULD RISE TO NEAR 90 ACROSS THE MTN VALLEYS TO MID TO UPPER 90S EAST. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... AS OF 100 PM EDT MONDAY...THE LATEST OP MODELS AND GFS ENSEMBLE MEMBERS ARE IN GOOD AGREEMENT FRI THROUGH THE WEEKEND WITH A OMEGA BLOCK SETTING UP ACROSS THE NRN ATL OCEAN. THIS WILL INDUCE AND DEEPEN ANOTHER EAST COAST TROF AND ALLOW A COLD FRONT INTO THE AREA BY SAT. THE FRONT IS EXPECTED TO STALL ACROSS THE CWFA SAT THROUGH SUN AND PERHAPS LIFT A LITTLE NORTH ON MON. THE STRONGEST UPPER FORCING WILL REMAIN NORTH OF THE AREA...HOWEVER GOOD OVERALL DYNAMICAL LIFT AND H3 DIV ALONG WITH PLENTY OF LLVL INSTABILITY WILL BE AVAILABLE FOR STRONG TO SEVERE DIURNAL TSTMS EACH DAY EXPECT PERHAPS SUN. NOCTURNAL ACTIVITY IS ALSO PROBABLE FRI/SAT NIGHT WITH THE FROPA LATE FRI AND A REINFORCING S/W PUSHING IN LATE SAT. POPS WERE MAINTAINED AT NEAR CLIMO...HOWEVER IF THIS PATTERN AND S/W TIMING PERSISTS OVER THE NEXT COUPLE MODEL RUNS...AN INCREASE IN POPS WILL BE WARRANTED FOR FRI/SAT. SUN LOOKS TO BE THE DRIEST DAY WITH FAIRLY STRONG HIPRES BUILDING IN...YET THE FRONT WILL BE SHUNTED JUST TO THE SOUTH...SO SLIGHT CHANCE POPS WERE CARRIED THROUGH THE DAY. MON WILL BE ACTIVE AGAIN AS ANOTHER SHOT OF UPPER ENERGY ROUNDS THE WRN RIDGE AND TRAVERSES THE REGION. MAX AND MIN TEMPS WILL BE RIGHT AROUND OR PERHAPS A COUPLE DEGREES ABOVE NORMAL FRI/SAT. WITH NW/LY FLOW SETTING UP SUN...EXPECT A COUPLE DEGREES COOLER IN THE MTNS SUN AND PERHAPS EVEN MON. YET...A GOOD DOWNSLOPE WARMING COMPONENT WILL ENABLE MAXES RIGHT AROUND NORMAL OVER THE NON/MTNS BOTH SUN AND MON. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... AT KCLT...SCT TSTMS ARE BEGINNING TO DEVELOP OVER THE NC FOOTHILLS. USING THE DISTANCE TIME OF ARRIVAL TOOL IN AWIPS...THE CELL IN EASTERN MCDOWELL COUNTY WOULD AFFECT THE AIRFIELD AROUND 2015 UTC. WHILE THAT INDIVIDUAL CELL WILL PROBABLY DIE...MORE STORMS ARE LIKELY ALONG THE OUTFLOW BNDRY AND A TEMPO GROUP FOR THUNDER HAS BEEN ADDED FROM 20-22 UTC. WINDS WILL BE VARIABLE WITH THE LEE TROUGH OVER THE AIRFIELD THIS AFTERNOON. HOWEVER...MOST SURROUNDING SITES ARE OUT OF THE WSW AND THAT/S WHAT I/LL CARRY AT KCLT. NO CIG OR VISBY PROBLEMS ARE EXPECTED OVERNIGHT AND CONVECTION SHOULD DIMINISH AFTER SUNSET. AND ELSEWHERE...SCT TSTMS ARE DEVELOPING ALONG THE BLUE RIDGE AS WELL AS BACK INTO ERN TN. WILL CARRY VCTS AT ALL AIRFIELDS...STARTING EARLIEST AT KAVL AND KHKY...AND A LITTLE LATER OVER THE UPSTATE AS IT WILL TAKE A COUPLE HOURS FOR OUTFLOW BNDRYS TO MAKE IT TOWARD THE I-85 CORRIDOR. WINDS WILL GENERALLY BE OUT OF THE W TO WSW THIS AFTN...WITH KAVL OUT OF THE NW. THE WINDS WILL BE VARIABLE AT TIMES OVER THE UPSTATE AS A WEAK LEE TROUGH IS OVER THAT AREA. SOME MVFR FOG IS POSSIBLE AT KAVL...BUT NOT LOOKING FOR ANY SIGNIFICANT CIG OR VSBY RESTRICTIONS OVERNIGHT...UNLESS AN AIRFIELD HAPPENS TO GET A HEAVY SHRA. OUTLOOK...SHOWER AND TSTM ACTIVITY WILL INCREASE A LITTLE OVER THE REGION TUE AND WED AS A WEAK FRONT DROPS INTO THE REGION. NOT LOOKING FOR MUCH IN THE WAY OF OVERNIGHT RESTRICTIONS OUTSIDE OF AREAS THAT SEE LOCALLY HEAVY RAIN. ANOTHER FRONT MAY BRING MORE WIDESPREAD CONVECTION AGAIN ON FRIDAY. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...SBK NEAR TERM...MCAVOY SHORT TERM...NED LONG TERM...SBK AVIATION...MCAVOY
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1056 PM CDT TUE JUL 24 2012 .DISCUSSION.../ISSUED AT 850 PM CDT/ MAIN CONCERN TONIGHT IS CONVECTION. PER KABR SOUNDING A VERY STRONG CAP REMAINS IN PLACE OVER THE ENTIRE AREA AS THE WARM FRONT IS NOW NORTH OF HWY 14 IN SD AND VERY CLOSE KMML AND KMWM IN MINNESOTA. THE LOW LEVEL JET IS REALLY FOCUSING ON THE 850 THETA-E GRADIENT IN NORTHEAST SOUTH DAKOTA LATER TONIGHT. FINALLY...THE UPPER FORCING FOR ASCENT IS RATHER WEAK AND WILL NOT HELP BREAK THE CAP. EXPECTATION IS THAT CURRENT CONVECTION ALONG THE SURFACE FRONT WEST OF WINNER WILL MOVE NORTHEAST BUT NEW CONVECTION IS UNLIKELY TO DEVELOP AS THE FRONT APPROACHES CHAMBERLAIN AND GREGORY AS THE BOUNDARY LAYER STABILIZES. WHILE ONE CANNOT COMPLETELY RULE OUT A THUNDERSTORM DEVELOPING ALONG OR BEHIND THE FRONT SOUTH OF HWY 14...THE CHANCES SEEM MUCH LOWER DUE TO THE FRONT BEING SO FAR NORTH. THE HRRR SUPPORTS THIS SOLUTION WITH LITTLE OR NO CONVECTION EVEN MOVING EAST OF THE MISSOURI RIVER SOUTH OF HIGHWAY 14. SO HAVE LOWER POPS TO 20 PERCENT AND SHIFTED THEM TO BE NORTH OF A CHAMBERLAN TO BROOKINGS TO MARSHALL LINE. ALSO WITH THE FRONT SO FAR NORTH WARM AIR AND SOUTH WINDS AROUND 10 KTS WILL HELP KEEP TEMPERATURES IN THE MID 70S SO HAVE RAISED LOWS IN SW MN. HAVE ALSO DECREASED CLOUDS THROUGH MUCH OF THE NIGHT AS MUCH OF THE CONVECTIVE DEBRIS WILL REMAIN OVER THE NRN CWA AND NOT REALLY APPEAR UNTIL LATER TONIGHT. UPDATED GRIDS...ZFP AND PFM AVAILABLE./SCHUMACHER && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ GENERALLY EXPECTING VFR CONDITIONS THROUGH 06Z THURSDAY. SOUTH OR SOUTHEASTERLY WINDS AROUND 10 KTS WILL CONTINUE THROUGH THE NIGHT. A COLD FRONT WILL PUSH THROUGH THE CWA TONIGHT INTO TOMORROW. IT IS TRENDING SLIGHTLY SLOWER AND SHOULD BE ENTERING THE NORTHWEST AROUND 9Z AND EXITING THE SOUTHEAST BY 22Z. WINDS WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT...AND WE MAY SEE SOME GUSTS TO 20 KTS TOMORROW. CONVECTION CHANCES LOOK MINIMAL TONIGHT...WITH MOST OF THE ACTIVITY STAYING TO OUR NORTH. THE STORMS OVER CENTRAL SOUTH DAKOTA COULD IMPACT KHON...BUT THINKING IS THESE STORMS STAY NORTH...SO PROBABILITY IS TOO LOW TO INCLUDE IN THE TAFS. WILL HAVE SOME MID LEVEL CLOUDINESS TOMORROW BEHIND THE FRONT...AND MAYBE A SHOWER...BUT NOTHING SIGNIFICANT. THE BEST CHANCE OF SEEING A HEAVIER THUNDERSTORM TOMORROW AFTERNOON AND EVENING IS ACROSS NORTHWEST IOWA...POSSIBLY IMPACTING KSUX...BUT EVEN THIS PROBABILITY SEEMS LOW AT THIS TIME. /CHENARD && .PREV DISCUSSION.../ISSUED AT 315 PM CDT/ LIGHT PRECIPITATION CONTINUES TO FALL JUST NORTH OF OUR FORECAST AREA LATE THIS AFTERNOON ALONG AN AXIS OF MID LEVEL MOISTURE AND 650-600MB FRONTOGENESIS. THE FRONTOGENESIS IS LIKELY TO STAY IN THAT AREA THIS EVENING...THEN A SHORT WAVE WILL IMPACT AREAS TO THE NORTH OF OUR FORECAST AREA OVERNIGHT. CONVECTION IS BEGINNING TO FIRE AT THIS TIME IN WESTERN/CENTRAL ND...AS WELL AS WESTERN SD...WHICH IS PROBABLY THE LEADING EDGE OF THIS SHORT WAVE. THE MODEL TREND HAS BEEN FURTHER NORTH WITH THE SHORT WAVE WHICH CURRENTLY LOOKS VERY REASONABLE GIVEN HOW VERY WARM THE MID LEVEL TEMPERATURES ARE IN THIS AREA. THEREFORE DECREASED POPS ALONG OUR NORTHERN ZONES TONIGHT...DRAGGING SOME LOW POPS SOUTHWARD ALONG A WIND SHIFT ASSOCIATED WITH A WEAK COLD FRONT. THE COLD FRONT WILL EDGE WELL INTO OUR FORECAST AREA BY LATE TONIGHT BUT LOWS WILL STILL BE QUITE WARM. ON WEDNESDAY...ONLY SMALL POPS ARE WARRANTED NEAR THE SURFACE WIND SHIFT AS THE FRONT CONTINUES TO MOVE EASTWARD. NAM 850MB TEMPERATURES ARE SUBSTANTIALLY COOLER ON WEDNESDAY WHEN COMPARED TO TODAY WITH AFTERNOON HIGHS CLOSER TO NORMAL...BUT STILL A CATEGORY OR TWO ABOVE AVERAGE FOR THIS TIME OF YEAR. FRONT WILL CONTINUE TO MOVE AWAY FROM CWA WEDNESDAY NIGHT AND ANY LINGERING THREAT OF THUNDERSTORMS ACROSS THE FAR SOUTHEAST SHOULD END IN THE EVENING. OTHERWISE...COOLING IN THE LOW LEVELS WILL LAG A BIT WITH MAIN PUSH OF COOLER AIR LATER WEDNESDAY NIGHT AND THURSDAY. SO LOWS WEDNESDAY SHOULD ONLY DROP INTO THE 60S WHILE HIGHS ON FRIDAY STILL RISE INTO THE 80S TO LOWER 90S WITH COOLEST TEMPERATURES OVER SOUTHWEST MINNESOTA. SHORT WAVE WILL DROP SOUTHEAST ACROSS NORTHERN MINNESOTA AND WITH COOLER AIR ALOFT WILL LIKELY SEE SOME DECENT LAPSE RATES THAT MAY BE ENOUGH TO PRODUCE ISOLATED AFTERNOON THUNDERSTORMS EAST OF I29. SO WILL KEEP A 20% EAST OF I29 THURSDAY AFTERNOON. DRY AND PLEASANT WEATHER CAN BE EXPECTED FRIDAY AS SURFACE HIGH DROPS INTO NORTHERN PLAINS. SO TEMPERATURES WILL BE CLOSE TO NORMAL WITH LOWER HUMIDITY. ON SATURDAY...HEIGHTS BEGIN TO BUILD ACROSS THE NORTHERN PLAINS WITH WEAK WAVE MOVING OVER THE RIDGE. FORCING NOT ALL THAT IMPRESSIVE BUT COULD BE ENOUGH TO TRIGGER A FEW THUNDERSTORMS ACROSS WESTERN CWA SATURDAY AFTERNOON AND ACROSS CWA SATURDAY NIGHT. ANOTHER WAVE WILL RIDE RIDGE SUNDAY AND WILL KEEP SMALL CHANCE IN WITH THIS FEATURE TOO. WITH THE RISING HEIGHTS WILL ALSO SEE WARMER TEMPERATURES AND HIGHER HUMIDITY...BUT NOTHING LIKE THE CURRENT HEAT. HIGHS WILL BE IN THE 80S AND 90S. WILL BE WARMER MONDAY AND TUESDAY AS RIDGE CONTINUES TO BUILD. THIS WILL PRODUCE HIGHS IN THE 90S MOST PLACES...AND POSSIBLY WARMER ACROSS WESTERN CWA. FOR NOW WILL LEAVE MONDAY AND TUESDAY DRY...BUT SPOTTY NOCTURNAL STORMS MAY BE POSSIBLE AS THEY DEVELOP OVER WESTERN HIGH PLAINS AND MOVE EAST. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR IAZ001>003-012>014- 020>022-031-032. MN...NONE. NE...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR NEZ013-014. SD...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR SDZ038-039-050- 052>055-057>071. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
850 PM CDT TUE JUL 24 2012 .DISCUSSION.../ISSUED AT 850 PM CDT/ MAIN CONCERN TONIGHT IS CONVECTION. PER KABR SOUNDING A VERY STRONG CAP REMAINS IN PLACE OVER THE ENTIRE AREA AS THE WARM FRONT IS NOW NORTH OF HWY 14 IN SD AND VERY CLOSE KMML AND KMWM IN MINNESOTA. THE LOW LEVEL JET IS REALLY FOCUSING ON THE 850 THETA-E GRADIENT IN NORTHEAST SOUTH DAKOTA LATER TONIGHT. FINALLY...THE UPPER FORCING FOR ASCENT IS RATHER WEAK AND WILL NOT HELP BREAK THE CAP. EXPECTATION IS THAT CURRENT CONVECTION ALONG THE SURFACE FRONT WEST OF WINNER WILL MOVE NORTHEAST BUT NEW CONVECTION IS UNLIKELY TO DEVELOP AS THE FRONT APPROACHES CHAMBERLAIN AND GREGORY AS THE BOUNDARY LAYER STABILIZES. WHILE ONE CANNOT COMPLETELY RULE OUT A THUNDERSTORM DEVELOPING ALONG OR BEHIND THE FRONT SOUTH OF HWY 14...THE CHANCES SEEM MUCH LOWER DUE TO THE FRONT BEING SO FAR NORTH. THE HRRR SUPPORTS THIS SOLUTION WITH LITTLE OR NO CONVECTION EVEN MOVING EAST OF THE MISSOURI RIVER SOUTH OF HIGHWAY 14. SO HAVE LOWER POPS TO 20 PERCENT AND SHIFTED THEM TO BE NORTH OF A CHAMBERLAN TO BROOKINGS TO MARSHALL LINE. ALSO WITH THE FRONT SO FAR NORTH WARM AIR AND SOUTH WINDS AROUND 10 KTS WILL HELP KEEP TEMPERATURES IN THE MID 70S SO HAVE RAISED LOWS IN SW MN. HAVE ALSO DECREASED CLOUDS THROUGH MUCH OF THE NIGHT AS MUCH OF THE CONVECTIVE DEBRIS WILL REMAIN OVER THE NRN CWA AND NOT REALLY APPEAR UNTIL LATER TONIGHT. UPDATED GRIDS...ZFP AND PFM AVAILABLE./SCHUMACHER && .AVIATION.../FOR THE 00Z TAF ISSUANCE/ GENERALLY EXPECTING VFR CONDITIONS THROUGH 0Z THURSDAY. SOUTH OR SOUTHEASTERLY WINDS AROUND 10 KTS WILL CONTINUE THROUGH THE NIGHT. A COLD FRONT WILL PUSH THROUGH THE CWA TONIGHT INTO TOMORROW...ENTERING THE NORTHWEST AROUND 8Z AND EXITING THE SOUTHEAST BY 20Z. WINDS WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT...AND WE MAY SEE SOME GUSTS TO 20 KTS TOMORROW. CONVECTION CHANCES LOOK MINIMAL TONIGHT...WITH MOST OF THE ACTIVITY STAYING TO OUR NORTH. IF SOMETHING DEVELOPS IN CENTRAL SOUTH DAKOTA KHON COULD GET A STORM TOWARDS MIDNIGHT...BUT THIS PROBABILITY IS TOO LOW TO INCLUDE IN THE TAFS. WILL HAVE SOME MID LEVEL CLOUDINESS TOMORROW BEHIND THE FRONT...AND MAYBE A SHOWER...BUT NOTHING SIGNIFICANT. THE BEST CHANCE OF SEEING A HEAVIER THUNDERSTORM TOMORROW AFTERNOON IS ACROSS NORTHWEST IOWA...POSSIBLY IMPACTING KSUX...BUT EVEN THIS PROBABILITY SEEMS LOW AT THIS TIME. /CHENARD && .PREV DISCUSSION.../ISSUED AT 315 PM CDT/ LIGHT PRECIPITATION CONTINUES TO FALL JUST NORTH OF OUR FORECAST AREA LATE THIS AFTERNOON ALONG AN AXIS OF MID LEVEL MOISTURE AND 650-600MB FRONTOGENESIS. THE FRONTOGENESIS IS LIKELY TO STAY IN THAT AREA THIS EVENING...THEN A SHORT WAVE WILL IMPACT AREAS TO THE NORTH OF OUR FORECAST AREA OVERNIGHT. CONVECTION IS BEGINNING TO FIRE AT THIS TIME IN WESTERN/CENTRAL ND...AS WELL AS WESTERN SD...WHICH IS PROBABLY THE LEADING EDGE OF THIS SHORT WAVE. THE MODEL TREND HAS BEEN FURTHER NORTH WITH THE SHORT WAVE WHICH CURRENTLY LOOKS VERY REASONABLE GIVEN HOW VERY WARM THE MID LEVEL TEMPERATURES ARE IN THIS AREA. THEREFORE DECREASED POPS ALONG OUR NORTHERN ZONES TONIGHT...DRAGGING SOME LOW POPS SOUTHWARD ALONG A WIND SHIFT ASSOCIATED WITH A WEAK COLD FRONT. THE COLD FRONT WILL EDGE WELL INTO OUR FORECAST AREA BY LATE TONIGHT BUT LOWS WILL STILL BE QUITE WARM. ON WEDNESDAY...ONLY SMALL POPS ARE WARRANTED NEAR THE SURFACE WIND SHIFT AS THE FRONT CONTINUES TO MOVE EASTWARD. NAM 850MB TEMPERATURES ARE SUBSTANTIALLY COOLER ON WEDNESDAY WHEN COMPARED TO TODAY WITH AFTERNOON HIGHS CLOSER TO NORMAL...BUT STILL A CATEGORY OR TWO ABOVE AVERAGE FOR THIS TIME OF YEAR. FRONT WILL CONTINUE TO MOVE AWAY FROM CWA WEDNESDAY NIGHT AND ANY LINGERING THREAT OF THUNDERSTORMS ACROSS THE FAR SOUTHEAST SHOULD END IN THE EVENING. OTHERWISE...COOLING IN THE LOW LEVELS WILL LAG A BIT WITH MAIN PUSH OF COOLER AIR LATER WEDNESDAY NIGHT AND THURSDAY. SO LOWS WEDNESDAY SHOULD ONLY DROP INTO THE 60S WHILE HIGHS ON FRIDAY STILL RISE INTO THE 80S TO LOWER 90S WITH COOLEST TEMPERATURES OVER SOUTHWEST MINNESOTA. SHORT WAVE WILL DROP SOUTHEAST ACROSS NORTHERN MINNESOTA AND WITH COOLER AIR ALOFT WILL LIKELY SEE SOME DECENT LAPSE RATES THAT MAY BE ENOUGH TO PRODUCE ISOLATED AFTERNOON THUNDERSTORMS EAST OF I29. SO WILL KEEP A 20% EAST OF I29 THURSDAY AFTERNOON. DRY AND PLEASANT WEATHER CAN BE EXPECTED FRIDAY AS SURFACE HIGH DROPS INTO NORTHERN PLAINS. SO TEMPERATURES WILL BE CLOSE TO NORMAL WITH LOWER HUMIDITY. ON SATURDAY...HEIGHTS BEGIN TO BUILD ACROSS THE NORTHERN PLAINS WITH WEAK WAVE MOVING OVER THE RIDGE. FORCING NOT ALL THAT IMPRESSIVE BUT COULD BE ENOUGH TO TRIGGER A FEW THUNDERSTORMS ACROSS WESTERN CWA SATURDAY AFTERNOON AND ACROSS CWA SATURDAY NIGHT. ANOTHER WAVE WILL RIDE RIDGE SUNDAY AND WILL KEEP SMALL CHANCE IN WITH THIS FEATURE TOO. WITH THE RISING HEIGHTS WILL ALSO SEE WARMER TEMPERATURES AND HIGHER HUMIDITY...BUT NOTHING LIKE THE CURRENT HEAT. HIGHS WILL BE IN THE 80S AND 90S. WILL BE WARMER MONDAY AND TUESDAY AS RIDGE CONTINUES TO BUILD. THIS WILL PRODUCE HIGHS IN THE 90S MOST PLACES...AND POSSIBLY WARMER ACROSS WESTERN CWA. FOR NOW WILL LEAVE MONDAY AND TUESDAY DRY...BUT SPOTTY NOCTURNAL STORMS MAY BE POSSIBLE AS THEY DEVELOP OVER WESTERN HIGH PLAINS AND MOVE EAST. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR IAZ001>003-012>014- 020>022-031-032. MN...NONE. NE...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR NEZ013-014. SD...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR SDZ038-039-050- 052>055-057>071. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
631 PM CDT TUE JUL 24 2012 .UPDATE... 00Z TAF DISCUSSION. && .AVIATION... VFR. LATEST SATELLITE IMAGERY SHOWS CLEAR SKIES ACROSS THE CWA WITH TSRA ACTIVITY NOTED TO THE NORTH ACROSS SOUTHERN KENTUCKY. SOME CIRRUS ANTICIPATED OVERNIGHT NEAR AREA AIRPORTS FROM THIS CONVECTION...BUT REMAINS UNCERTAIN IF ACTIVITY WILL SURVIVE INTO NORTHEAST PARTS OF THE FORECAST AREA AND IF CSV WILL SEE ANY IMPACTS. LATEST NAM AND HRRR RUNS INDICATE LITTLE TO NO EFFECTS TO CSV...AND WILL NOT MENTION TS ACTIVITY IN TAF ATTM. WITH H5 RIDGE AXIS OVER THE MID STATE ON WEDNESDAY...EXPECTING ONLY ISOLATED CUMULUS WITH LIGHT WEST WINDS AND NO CONVECTION. && .PREV DISCUSSION... /ISSUED 307 PM CDT TUE JUL 24 2012/ SHORT TERM...SKIES REMAINED MOSTLY SUNNY ACROSS THE MID STATE EARLY THIS AFTERNOON, WITH 2 PM TEMPERATURES PUSHING THROUGH THE LOWER AND MIDDLE 90S OVER WESTERN PARTS OF THE MID STATE. AREA RADARS SHOWED A FEW NEW THUNDERSTORMS POPPING UP ACROSS CENTRAL KENTUCKY, AND OUR NORTHWEST FLOW PATTERN MAY ALLOW SOME OF THOSE THUNDERSTORMS TO EVENTUALLY PROPAGATE DOWN INTO NORTHEASTERN MIDDLE TENNESSEE LATE TODAY OR TONIGHT. STILL EXPECT UPPER RIDGE TO BUILD ACROSS THE MID STATE FOR THE NEXT FEW DAYS, BEFORE A COLD FRONT FINALLY SWEEPS IN FROM THE NORTHWEST AND BRINGS ANOTHER ROUND OF THUNDERSTORMS AND SOME LOWER DEW POINTS AND LESS HOT CONDITIONS. WILL EXPAND THE HEAT ADVISORY AREA INTO OTHER PARTS OF WESTERN MIDDLE TENNESSEE WEDNESDAY AFTERNOON THROUGH THURSDAY AFTERNOON (INCLUDING THE NASHVILLE METRO AREA). HIGHS BOTH DAYS IN THE ADVISORY AREA WILL BE IN THE MIDDLE AND UPPER 90S, WITH MANY AREAS LIKELY TO SEE AFTERNOON HEAT INDEX VALUES BETWEEN 104 TO 107 DEGREES. HYDRO CONCERNS...RIGHT NOW, WE`RE LOOKING FOR GENERAL QPF TOTALS THURSDAY NIGHT AND FRIDAY TO AVERAGE AROUND ONE HALF INCH, WITH SOME LOCALLY HIGHER AMOUNTS OF AN INCH OR MORE IN THE AREAS OF STRONGEST THUNDERSTORM ACTIVITY. PW`S INCREASE TO AROUND 2 INCHES AS THE FRONT ROLLS THROUGH, SO WOULD NOT BE SURPRISED TO SEE SOME PONDING OF WATER AND LOCALIZED FLOOD PROBLEMS DEVELOP (ESPECIALLY IN AREAS THAT SAW THE HEAVY DOWNPOURS LAST THURSDAY). LONG TERM... AFTER THE COLD FRONT SWEEPS THROUGH THURSDAY NIGHT AND FRIDAY, DRIER AIR MOVES IN AND SIGNIFICANTLY LOWERS OUR CHANCE FOR RAIN OVER THE WEEKEND. ALTHOUGH TEMPERATURES WARM BACK INTO THE MIDDLE 90S BY EARLY WEEK, RAIN CHANCES ARE EXPECTED TO REMAIN ONLY IN THE SLIGHT CHANCE CATEGORY. && .OHX WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM 1 PM WEDNESDAY TO 7 PM CDT THURSDAY FOR TNZ007-026-027-056>061-093>095. HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR TNZ005-006-022>025. && $$ 55
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
955 PM CDT TUE JUL 24 2012 .UPDATE... ALTHOUGH THE 00Z RUNS OF THE NAM AND RUC FORECASTING DRIER CONDITIONS LATER TONIGHT...THE RUC INDICATING CONVECTION SPREADING FROM WEST TO EAST THROUGH AROUND 06Z TO 09Z WEDNESDAY. WITH MID AND UPPER TROUGH LOCATED OVER THE CENTRAL AND SOUTHERN ROCKIES INTO THE PANHANDLES AND PRECIP WATERS BETWEEN ONE AND ONE AND ONE QUARTER INCHES ALONG WITH PLENTY OF LOW LEVEL MOISTURE AND SHORTWAVE ENERGY ACROSS THE FORECAST AREA...SPREAD SLIGHT CHANCE POPS EASTWARD ACROSS ALL OF THE PANHANDLES THROUGH 12Z WEDNESDAY AND WENT WITH AREAL QUALIFIER WORDING. 00Z KAMA SOUNDING ALONG INDICATING LIFTED INDEX OF -3 AND CAPE NEAR 1000 JOULES. NAM FORECASTING ANOTHER LOW LEVEL SOUTHERLY JET OF 40 KNOTS SETTING UP BY 09Z WEDNESDAY...SIMILAR TO LAST NIGHT. CANNOT COMPLETELY RULE OUT CONVECTION DEVELOPING ANYWHERE IN THE FORECAST AREA OVERNIGHT TONIGHT. BUMPED UP WINDS TONIGHT SLIGHTLY AND INCREASED SKY COVER. ALSO...UPDATED FIRE WEATHER GRIDS WITH THE LATEST 00Z NAM DATA. CLEANED UP THE DISCUSSION IN THE FIRE WEATHER FORECAST PRODUCT TO REMOVE CONTRACTIONS AND CHANGE FROM WIND SPEEDS WORDING FROM KNOTS TO MPH. ALSO MENTIONED WIND SHIFT ASSOCIATED WITH COLD FRONTAL PASSAGE WEDNESDAY NIGHT AND THURSDAY. ALL PUBLIC AND FIRE WEATHER PRODUCTS HAVE BEEN UPDATED AND SENT. SCHNEIDER && .PREV DISCUSSION... /ISSUED 631 PM CDT TUE JUL 24 2012/ AVIATION... SLOW-MOVING ISOLATED THUNDERSTORMS SEEN ON 88D AT THIS TIME DO NOT APPEAR TO POSE THREAT TO TERMINALS THIS EVENING. WILL CONTINUE TO MONITOR. OTHERWISE...SOUTHERLY SURFACE WINDS SHOULD CEASE GUSTING THIS EVENING...AND THEN INCREASE AGAIN WEDNESDAY MORNING AS NOCTURNAL LOW- LEVEL JET MIXES DOWNWARD. COLD FRONT WILL ENTER NORTHWEST PART OF FORECAST AREA ON WEDNESDAY...BEING POISED NEAR KDHT AND KGUY DURING THE HEAT OF THE DAY. KDHT AND KGUY WILL HAVE GREATER CHANCE TO BE DIRECTLY IMPACTED BY SCATTERED THUNDERSTORMS FROM LATE AFTERNOON TO EARLY EVENING WEDNESDAY...AS SHORTWAVE TROF PROVIDES ADDITIONAL LIFT. VFR FORECAST CONTINUES NEXT 24 HOURS. COCKRELL PREV DISCUSSION... /ISSUED 323 PM CDT TUE JUL 24 2012/ DISCUSSION... REGIONAL COMPOSITE RADAR SHOWS DEVELOPMENT OF THE SECOND ROUND OF CONVECTION EXPECTED TO PERSIST INTO THE EVENING HOURS FOR THE SOUTHERN PORTION OF THE CWA. ALSO BREEZY SURFACE WINDS OF 15 TO 20 KTS WITH GUSTS UP TO 30 KTS HAVE DEVELOPED AS THE SURFACE GRADIENT ACROSS THE PANHANDLES TIGHTENS. REST OF TODAY AND TONIGHT...ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS EVENING AS AN UPPER LEVEL WAVE CONTINUES A SSE TO NNW TRACK AROUND THE BASE OF THE UPPER LEVEL RIDGE. WHILE THE SEVERE THREAT IS LOW WITH ANY CONVECTION THAT FORMS THIS EVENING...BRIEF WIND GUSTS UP TO 45 MPH COULD BE EXPERIENCED NEAR DECAYING CELLS. STORM ACTIVITY SHOULD END PRIOR TO MIDNIGHT AS THE WAVE MOVES NORTH OF THE PANHANDLES. WEDNESDAY THROUGH FRIDAY...THE STUBBORN UPPER LEVEL RIDGE BEGINS TO BREAK DOWN EARLY WEDNESDAY MORNING AS AN UPPER LOW MOVES THROUGH ALBERTA TOWARDS THE GREAT LAKES LOWERING THE HEIGHT FIELD ACROSS THE NORTHERN AND CENTRAL PLAINS. THE RESULTING WEAKNESS IN THE RIDGE WILL ALLOW A WEAK COLD FRONT TO DIVE INTO THE PANHANDLES WEDNESDAY AND EXIT THE CWA FRIDAY. BREEZY CONDITIONS CAN BE EXPECTED WEDNESDAY IN ADVANCE OF THE FRONT AS THE SURFACE GRADIENT TIGHTENS WITH SUSTAINED 15 TO 25 MPH SOUTHERLY WINDS AND OCCASIONAL GUSTS ABOVE 30 MPH. BY MIDDAY WEDNESDAY RAIN CHANCES WILL RAISE AS THE APPROACHING FRONT PROVIDES ADDITIONAL FORCING. THE SEVERE THREAT THROUGH FRIDAY WILL REMAIN LOW DUE TO LOW CAPE VALUES GENERALLY AROUND 1500 J/KG AND THE POOR DEFINITION OF THE FRONT. BRIEF DIURNAL BREAKS IN CONVECTIVE ACTIVITY CAN BE EXPECTED EARLY THURSDAY AND FRIDAY MORNING BEFORE REFORMING DURING THE DAY. THERE HAS BEEN SOME MODEL DISCONTINUITY CONCERNING THE SPEED AT WHICH THE FRONT WILL MOVE THROUGH THE AREA. THE NAM HAS BEEN THE MOST AGGRESSIVE AND PUSHES THE FRONT COMPLETELY THROUGH THE AREA BY LATE THURSDAY, WHILE THE GFS KEEPS THE FRONT IN THE CWA THROUGH LATE FRIDAY. THE ECMWF HAD BEEN TRENDING CLOSER TO THE NAM PREVIOUSLY BUT HAS BEGUN TO TREND CLOSER TO THE GFS WITH TIME. AS SUCH HAVE GONE WITH A BLEND OF THE GFS AND ECMWF OF THE SPEED OF THE FRONT AND KEPT RAIN CHANCES THROUGH FRIDAY. SATURDAY THROUGH WEDNESDAY...BY SATURDAY THE UPPER LEVEL RIDGE STRENGTHENS TO END RAIN CHANCES FOR THE REST OF THE WEEK AND THROUGH THE MIDDLE OF NEXT WEEK. TEMPERATURES...STUCK CLOSE TO THE GFS MAXIMUM TEMPERATURES THROUGH FRIDAY AND MINIMUM TEMPERATURES THROUGH THE FORECAST. LEANED CLOSER TO THE ECMWF HIGH TEMPERATURE TOWARDS THE END OF THE FORECAST AS THE GFS BEGAN TO TREND BACK TO CLIMO UNDER A STRENGTHENING RIDGE. 14 FIRE WEATHER... STRONG SOUTHERLY WINDS ARE EXPECTED TO DIMINISH DURING THE EVENING HOURS AS RELATIVE HUMIDITY VALUES BEGIN TO REBOUND. WILL SEE ANOTHER ROUND OF STRONG SOUTHERLY 20-FT WINDS OF 15 TO 20 KTS WEDNESDAY MAINLY IN THE NORTHEASTERN SECTIONS OF THE PANHANDLES. RELATIVE HUMIDITY VALUES AT THAT TIME ARE EXPECTED TO DROP TO BELOW 25 PERCENT BRIEFLY BEFORE REBOUNDING IN THE ADVANCE OF AN APPROACHING COLD FRONT. THE INCREASED MOISTURE WILL PROMOTE ISOLATED TO SCATTERED SHOWERS WEDNESDAY THROUGH FRIDAY. DRY AND HOT WEATHER IS EXPECTED TO RETURN BY THE WEEKEND. 14 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 03/11
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1134 PM CDT SUN JUL 22 2012 .DISCUSSION... SEE AVIATION FOR 06Z TAFS. && .AVIATION... SCT CIRRUS ABOVE 25 THSD FT IS EXPECTED THRU 09Z. SCT TO BKN STRATOCUMULUS AT 1 THSD TO 2 THSD FT IS EXPECTED VCNTY OF KAUS TO KSAT FROM 09Z TO 14Z...WHILE FURTHER WEST SCT CIRRUS ABOVE 25 THSD FT IS EXPECTED. A BRIEF PERIOD OF SCT CLOUDS AROUND 2 TO 3 THSD FT IS POSSIBLE VCNTY OF KDRT FROM 13Z TO 15Z. AFTER 15Z ON MONDAY SCT CUMULUS AT 4 THSD TO 8 THSD FT IS FORECAST...WITH HIGHER CIRRUS CLOUDS SCT ABOVE 25 THSD FT. ISOLATED SHRA/TSRA ARE POSSIBLE IN THE LATE AFTERNOON AND EVENING ON MONDAY...MAINLY EAST OF A KBMQ TO KPEZ LINE. SCT CIRRUS ABOVE 25 THSD FT IS EXPECTED MONDAY EVENING AFTER 03Z...BECOMING CIGS 1 THSD TO 2 THSD BKN VCNTY OF KAUS TO KSAT AFTER 08Z MONDAY NIGHT...WITH 2 THSD SCT VCNTY OF KDRT. S AND SE WINDS AT 5 TO 10 KNOTS WILL INCREASE TO 10 TO 15 KNOTS AFTER 17Z ON MONDAY. AFTER 06Z MONDAY NIGHT...S TO SE WINDS AT 5 TO 10 KNOTS IS FORECAST. && .PREV DISCUSSION... /ISSUED 913 PM CDT SUN JUL 22 2012/ UPDATE... REMOVED MENTIONING OF THE SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS FOR THE REST OF THIS EVENING/TONIGHT ACROSS THE NORTHERN HILL COUNTRY AND EASTERN COUNTIES. ALSO...ADJUSTED CLOUD COVERAGE FOR THE TONIGHT PERIOD. DISCUSSION... UPPER LEVEL RIDGE CONTINUES TO BUILD THIS EVENING ACROSS THE CENTRAL PLAINS PER 00Z 500 MB SOUNDING ANALYSIS AND IS SUPPRESSING CONVECTION ACROSS CENTRAL TEXAS THIS EVENING. ALL...WRF 3KM/NAM12 AND HRRR MODELS SUGGEST DRYING CONDITIONS FOR SOUTH CENTRAL TEXAS FOR TONIGHT AND THEREFORE...SHOWED SILENT 10 PERCENT POPS OR LESS FOR THIS PERIOD. ZONES OUT SHORTLY. PREV DISCUSSION... /ISSUED 656 PM CDT SUN JUL 22 2012/ DISCUSSION... SEE AVIATION FOR 00Z TAFS. AVIATION... SCT CIRRUS ABOVE 25 THSD FT IS EXPECTED THRU 09Z. SCT TO BKN STRATOCUMULUS AT 1 THSD TO 2 THSD FT IS EXPECTED VCNTY OF KAUS TO KSAT FROM 09Z TO 14Z...WHILE FURTHER WEST SCT CIRRUS ABOVE 25 THSD FT IS EXPECTED. A BRIEF PERIOD OF SCT CLOUDS AROUND 2 TO 3 THSD FT IS POSSIBLE VCNTY OF KDRT FROM 13Z TO 15Z. AFTER 15Z ON MONDAY SCT CUMULUS AT 4 THSD TO 8 THSD FT IS EXPECTED...WITH HIGHER CIRRUS CLOUDS SCT ABOVE 25 THSD FT. ISOLATED SHRA/TSRA ARE POSSIBLE IN THE LATE AFTERNOON AND EVENING ON MONDAY. SE WINDS AT 10 TO 15 KNOTS WILL BECOME S AND SE AT 5 TO 10 KNOTS AFTER MIDNIGHT TONIGHT...AND S TO SE AT 10 TO 15 KNOTS AFTER 15Z ON MONDAY. SCT CIRRUS ABOVE 25 THSD FT IS EXPECTED MONDAY EVENING AFTER 03Z...BECOMING CIGS 1 THSD TO 2 THSD BKN VCNTY OF KAUS TO KSAT AFTER 08Z MONDAY NIGHT... WITH 2 THSD SCT VCNTY OF KDRT. PREV DISCUSSION... /ISSUED 235 PM CDT SUN JUL 22 2012/ DISCUSSION... A WEAK UPPER LEVEL CYCLONIC SHEAR FEATURE IS DRIFTING WEST FROM CENTRAL TX INTO WEST CENTRAL TX THIS AFTERNOON. MID-LEVEL MOISTURE POOLING ABOUT THIS FEATURE WILL SUPPORT ISOLATED STRONG STORMS WITH GOOD DOWNDRAFT POTENTIAL DUE TO TEMPS IN THE MID-UPPER 90S. THE UPPER LEVEL SHEAR FEATURE IS LOOSELY CONNECTED WITH ADDITIONAL INSTABILITY OVER THE NW GULF INTO THE TX/LA BORDER WHERE CYCLONIC SHEAR IS MORE EVIDENT IN THE MID LEVELS. MOISTURE AND CONVECTION OVER THE GULF SHOULD WORK NW INTO THE COASTAL PRAIRIES LATE MONDAY INTO TUESDAY...PUSHING PWAT VALUES CLOSE TO 2 INCHES OVER OUR SOUTHEASTERN COUNTIES. WHILE THIS COULD SIGNAL GOOD RAIN CHANCES FOR THE COASTAL PRAIRIES...STRENGTHENING MID-LEVEL STABILITY IS ALSO FORECAST TO BUILD OVER THIS REGION AS THE BROADER UPPER RIDGE AXIS TILTS TO THE SOUTHEAST OVER THE LOWER MISSISSIPPI RIVER VALLEY. SO WITH LOW CONFIDENCE...WILL COVER THE AREA WITH A BROAD BRUSH OF SLIGHT CHC POPS MONDAY EVENING AND CONCENTRATE THE SLIGHT CHC POPS ALONG AND EAST OF I-35 FOR TUESDAY. THE PWAT VALUES ARE EXPECTED TO DECREASE TUESDAY INTO WEDNESDAY AS A MORE SWLY CONTINENTAL FLOW DEVELOPS ALOFT. THE HOTTER AND DRIER ECMWF PATTERN IS FAVORED FOR LATE IN THE WEAK AS MODEL TRENDS SUGGEST THE UPPER RIDGE AXIS...WHICH HAS BROUGHT HEAT AND DROUGHT TO THE CENTRAL US...IS ABOUT TO SHIFT SOUTHWARD INTO N TX. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 74 96 74 97 75 / - 20 20 20 10 AUSTIN BERGSTROM INTL AIRPORT 73 95 72 96 73 / - 20 20 20 10 NEW BRAUNFELS MUNI AIRPORT 73 94 72 94 72 / - 10 20 20 10 BURNET MUNI AIRPORT 75 95 74 95 74 / - 10 20 10 10 DEL RIO INTL AIRPORT 78 100 77 99 78 / - - 10 10 - GEORGETOWN MUNI AIRPORT 74 95 74 95 74 / - 20 20 20 10 HONDO MUNI AIRPORT 72 97 73 97 73 / - 10 20 10 10 SAN MARCOS MUNI AIRPORT 73 94 73 94 73 / - 20 20 20 10 LA GRANGE - FAYETTE REGIONAL 74 92 74 92 74 / 10 20 20 20 10 SAN ANTONIO INTL AIRPORT 75 95 76 95 76 / - 10 20 20 10 STINSON MUNI AIRPORT 74 96 74 96 75 / - 10 20 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...08 SYNOPTIC/GRIDS...17
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1128 PM CDT SUN JUL 22 2012 .SHORT TERM...TONIGHT THROUGH WEDNESDAY 311 PM CDT SUN JUL 22 2012 THE MAIN FOCUS GOING THROUGH MID WEEK IS WITH THE PRECIPITATION CHANCES AND HOW WARM IT WILL GET TOMORROW. LITTLE TO NO CHANGE TO THE UPPER LEVEL PATTERN AS A LARGE...YET FLAT RIDGE OF HIGH PRESSURE REMAINS CENTERED ON THE CENTRAL PLAINS. THE FOCUS FOR ANY PRECIPITATION CHANCES HAS BEEN WITH ANY MID LEVEL SHORT WAVE TROUGHS THAT HAVE DROPPED DOWN FROM THE NORTHWEST FROM THE DAKOTAS. THIS MORNINGS SHORT WAVE HAS PROPAGATED OFF TO THE EAST WITH A CLOSED MID LEVEL LOW TRACKING EAST ACROSS SOUTH CENTRAL CANADA. THIS MORE POTENT MID LEVEL LOW HAS LED TO STRONGER SOUTHERLY LOW LEVEL FLOW WITH ONE SURFACE LOW/LEFT OVER MCV OVER SOUTHERN MINNESOTA AND A DEEPER LOW NORTH OF WINNIPEG. THE INITIAL FOCUS FOR THE REST OF THIS AFTERNOON AND EVENING IS WITH THE WARM FRONT THAT EXTENDS EAST OUT OF THE MCV LOW TOWARD EAU CLAIRE AND HAS BEEN LIFTING NORTH THROUGH THE AFTERNOON. SKIES HAVE CLEARED ACROSS MUCH OF NORTHERN IOWA WITH SCATTERED CONVECTION/CLOUD COVER STILL OVERHEAD THROUGH MUCH OF SOUTHERN MINNESOTA AND WESTERN WISCONSIN. WITH INVERTED V SOUNDINGS NOTED FROM THE WARM SECTOR WHERE SURFACE TEMPERATURES QUICKLY JUMPED INTO THE 90S...THE CONCERN IS THAT SOME SURFACE BASED STORMS WILL BE IGNITED AS THE MCV MOVES IN AND BRINGS SOME STRONG WINDS ALONG WITH IT. THIS AFTERNOON/S HRRR RUNS HAVE BEEN HITTING WESTERN WISCONSIN HARDER WITH CONVECTION ALONG THE WARM FRONT WHICH APPEARS TO BE OVERDONE. WHILE CONFIDENCE IS LOW WITH HOW THE REST OF THIS AFTERNOON AND EVENING WILL PAN OUT...THERE APPEARS TO BE ENOUGH OF A THREAT TO CARRY SOME CHANCES FOR PRECIPITATION INTO THE EVENING. BEYOND TONIGHT...THE MAIN COLD FRONT DROPS SOUTH TOMORROW AND BECOMES STATIONARY IN NORTHERN IOWA BY TOMORROW NIGHT. THIS FEATURE MAY BE ENOUGH OF A KICKER TO INITIATE CONVECTION ALONG IT TOMORROW DESPITE HIGH LFC/S AND LACK OF UPPER LEVEL SUPPORT. WITH INCREASING 850-500MB FRONTOGENESIS ALONG THIS FRONTAL ZONE...ADDED SOME SMALL SHOWER/STORM CHANCES TOMORROW AFTERNOON AND INCREASED THE EVENING CHANCES. SEVERE WEATHER DOES NOT LOOK VERY LIKELY...BUT INVERTED V SOUNDINGS OUT AHEAD OF THE FRONT COULD LEAD TO SOME GUSTY WINDS WITH SOME OF THE STORMS THAT DO MANAGE TO DEVELOP. WITH THE COLD FRONT BRINGING SOME CLOUD COVER ALONG WITH IT AND DEEP AFTERNOON MIXING LEADING TO DRYING DEW POINTS...IT DOES NOT APPEAR AS THOUGH HEAT INDICES WILL WARM UP MUCH BEYOND 100 DEGREES. THE MISSISSIPPI AND WISCONSIN RIVER VALLEYS MAY BE THE EXCEPTION WHERE TEMPERATURES WILL BE A FEW DEGREES HIGHER. AFTER COLLABORATION WITH NEIGHBORING OFFICES...HAVE DECIDED TO NOT ISSUE A HEAT ADVISORY FOR TOMORROW ACROSS NORTHEAST IOWA/SOUTHWEST WISCONSIN. THE BAROCLINIC ZONE ALONG THE FRONT BECOMES MORE ACTIVE MONDAY NIGHT THROUGH WEDNESDAY AS THE LOW LEVEL FRONTOGENESIS STAYS STRONG AND THE LOW LEVEL MOISTURE TRANSPORT INCREASES. CONFIDENCE IS PRETTY HIGH THAT SOME MORE SIGNIFICANT RAINS WILL COME AS THIS PATTERN SETS UP...PARTICULARLY AT NIGHT WHEN THE LOW LEVEL JET DEVELOPS AND NOSES UP INTO THE REGION. CAN NOT RULE OUT SOME SEVERE WEATHER OVER THIS TIME FRAME AS WELL WITH UNSTABLE AIR POOLING ALONG THE FRONT ALONG WITH DECENT DEEP LAYER SHEAR...PARTICULARLY IF THE BOUNDARY HANGS UP ACROSS THE AREA IN NORTHEAST IOWA AND NOT TO THE SOUTH AS FORECAST. THE BETTER CHANCES FOR ORGANIZED CONVECTION MAY BE ON TUESDAY NIGHT INTO WEDNESDAY AS A MID LEVEL SHORT WAVE TROUGH COMES THROUGH AND BRINGS A LOW ALONG THE STATIONARY FRONT. .LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY NIGHT 311 PM CDT SUN JUL 22 2012 THE STATIONARY FRONT WILL GET A KICK TO THE SOUTH IN THE WAKE OF THE SURFACE LOW THAT COMES THROUGH ON WEDNESDAY THOUGH CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO FRIDAY AS A CLOSED MID LEVEL LOW DROPS SOUTHEAST FROM THE NORTHERN PLAINS INTO THE GREAT LAKES. RIDGING THEN MOVES IN FROM THE WEST FRIDAY NIGHT INTO SATURDAY AT THE SURFACE AND ALOFT AND SHOULD BRING DRIER CONDITIONS ALONG WITH IT. TEMPERATURES LOOK SEASONAL IN THE LOW TO MID 80S ACROSS THE REGION WITH 850MB TEMPERATURES DROPPING INTO THE +15C AREA. && .AVIATION...TONIGHT AND MONDAY 1128 PM CDT SUN JUL 22 2012 BROAD...RELATIVELY FLAT RIDGE OVER NATIONS MID SECTION HAS AREA IN BETWEEN TWO WEATHER IMPULSES. ONE WAVE MOVING ACROSS ONTARIO IS SWEEPING IN DEBRIS HIGH CLOUDINESS FROM THE NORTHWEST WHILE LOW LEVEL JET IN RESPONSE TO WEAK SHORT WAVE ENERGY CROSS RIDGE IS FIRING NEW CONVECTION OVER SOUTHERN SOUTH DAKOTA INTO NORTHWEST IOWA. LOW LEVEL FLOW IS VERY WEAK AROUND IMMEDIATE AREA AND WITH DEW POINTS UP TONIGHT A BIT MORE MVFR FOG POSSIBLE. FEELING IS MID AND HIGH LEVEL CLOUDS COMING IN FROM THE WEST SHOULD KEEP BULK OF AREA IN VFR CONDITIONS SO WON`T HIT FOG TOO HARD. A LITTLE UNCLEAR IF CONVECTION TO THE WEST WILL IMPACT AREA AT ALL OVERNIGHT. BEST CONVERGENCE REMAINS WELL WEST BUT SOME MESOSCALE GUIDANCE SUGGESTS WE COULD GET SOME DECAYING SHOWERS INTO WESTERN AREAS AFTER DAYBREAK. MAY INCLUDE BRIEF WINDOW AT KRST FOR NOW BUT BULK OF DAY SHOULD REMAIN QUIET WITH VFR CONDITIONS. BIT STRONGER WAVE HEADING INTO MONDAY EVENING WILL LIKELY GENERATE WARM AIR ADVECTION OVER BOUNDARY IN THE AREA. THIS COULD LEAD TO MORE WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT. DETAILS WILL NEED TO BE WORKED OUT IN CLOSER TIME FRAME BUT FOR NOW INTRODUCED SHOWERS INTO TAF SITES WITH HIGHER CONFIDENCE. && .ARX WATCHES/WARNINGS/ADVISORIES... 311 PM CDT SUN JUL 22 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM....HALBACH AVIATION.....SHEA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
302 AM CDT WED JUL 25 2012 .DISCUSSION... ISSUED 300 AM CDT WED JUL 25 2012 LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY CURVING AROUND THE WEST AND SOUTHERN FRINGES OF THE FORECAST AREA EARLY THIS MORNING...PUSHING NORTHWARD. HAVE BEEN SEEING SOME SCATTERED THUNDERSTORMS DEVELOPING OVER MAINLY THE EASTERN HALF OF THE CWA THE LAST FEW HOURS...BUT A LARGE AREA OF CLEAR SKIES WAS JUST TO OUR WEST. TEMPERATURES NORTH OF I-74 HAVE DIPPED INTO THE LOWER 70S AS OF 2 AM...BUT STILL SEEING QUITE A FEW LOWER 80S CLOSER TO THE BOUNDARY. MAIN CONCERNS ARE IN THE SHORT TERM...NAMELY THE RECORD HEAT TODAY AND ANY POTENTIAL NEED FOR ADJUSTMENTS TO HEADLINES. ALSO HAVE CONCERNS WITH CONVECTIVE DEVELOPMENT OVER THE NEXT 24 TO 36 HOURS. SHORT TERM...TODAY THROUGH THURSDAY NIGHT... LATEST VERSIONS OF THE NAM-12 AND HRRR HAVE A FAIR HANDLE ON THE CURRENT CONVECTION...AND HAVE THE RAIN OUT OF THE AREA BY MID- MORNING. WILL MAKE A LAST-MINUTE CALL ON HOW TO HANDLE THE ACTIVITY IN THE ZONES. OTHERWISE...THE MAIN STORY WILL BE THE BRUTAL HEAT. TIME-HEIGHT HUMIDITY CROSS SECTIONS SHOWING ANY CLOUD COVER RAPIDLY MOVING EAST OF THE AREA LATE THIS MORNING AS THE FRONT LIFTS NORTH OF THE AREA. DEEP MIXING FROM AROUND 750 MB SHOULD BRING DRIER AIR DOWN FROM ABOVE..AND HELP DROP DEW POINTS INTO THE 60-65 DEGREE RANGE THIS AFTERNOON. WINDS ALSO EXPECTED TO PICK UP AND GUST TO AROUND 20-25 MPH. TEMPERATURES AGAIN EXPECTED TO SOAR INTO TRIPLE DIGIT TERRITORY...AND HAVE NOT MADE ANY CHANGES TO EARLIER HIGHS OF 103-107. MUCH OF THE CWA LIKELY TO SEE RECORD HIGHS TODAY. WITH THE DRIER AIR...HEAT INDEX VALUES SHOULD ONLY BE A FEW DEGREES ABOVE THE OBSERVED TEMPERATURES. THERE ARE SOME CONCERNS THAT THE HEAT ADVISORY WILL NEED TO BE EXTENDED IN AREAS SOUTH OF I-70 THROUGH THURSDAY. HOWEVER...THE NEED IS NOT CLEAR-CUT...DUE TO POTENTIAL FOR CLOUDS AND STORMS. UPPER RIDGE OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO FLATTEN TODAY...AS A COLD FRONT DROPS SOUTHEAST TOWARD THE AREA. PASSAGE OF THE FRONT THROUGH OUR CWA WILL LIKELY TAKE UNTIL MIDDAY OR EARLY AFTERNOON ON THURSDAY. WILL SEE SCATTERED THUNDERSTORMS WEST OF I-55 DEVELOP LATER TONIGHT AS THE FRONT APPROACHES...THEN INCREASE OVER THE CWA ON THURSDAY WITH THE HEATING AHEAD OF THE FRONT. MAIN SEVERE WEATHER THREAT TODAY WILL REMAIN TO THE NORTH...BUT SOME SEVERE STORMS ARE POSSIBLE LATE THURSDAY MORNING INTO THE AFTERNOON. WILL SEE SCATTERED STORMS LINGER INTO EVENING ACROSS THE EASTERN CWA. THE NAM MODEL DOES DEVELOP SOME ADDITIONAL SHOWERS LATE THURSDAY NIGHT WITH A SECONDARY BOUNDARY COMING THROUGH THE AREA...BUT THIS DOES NOT SEEM LIKELY AT THE MOMENT. LONG TERM...FRIDAY THROUGH TUESDAY... UPPER RIDGE TO RE-ESTABLISH ITSELF OVER THE ROCKIES THIS WEEKEND...WITH A BROAD TROUGH PUSHING THROUGH THE GREAT LAKES. THIS WILL ALLOW FOR SOME MORE REASONABLE TEMPERATURES FOR THE WEEKEND. AS THE RIDGE BEGINS TO SHIFT BACK EASTWARD AGAIN... POTENTIAL FOR MCS ACTIVITY OVER THE TOP OF THE RIDGE WILL INCREASE OVER OUR AREA. MOST LIKELY TIME FRAMES FOR THIS WILL BE FROM SUNDAY NIGHT THROUGH TUESDAY...BUT EXACT LOCATIONS STILL A BIT OF A QUESTION. AS SUCH...WILL NOT GO OVERBOARD ON THE RAIN CHANCES AT THIS TIME. GEELHART && .AVIATION... ISSUED 1152 PM CDT TUE JUL 24 2012 VFR CONDITIONS WILL CONTINUE NEXT 24HRS AT ALL TAF SITES. SCATTERED AC WILL LIKELY CONTINUE AT ALL SITES OVERNIGHT AND INTO THE MORNING HOURS. AC APPEARS TO BE IN RESPONSE TO THE SFC FRONT LIFTING BACK NORTH OVERNIGHT. BASED ON SATELLITE LOOPS FROM THIS AFTERNOON BACK WEST...BELIEVE SCATTER AC WILL CONTINUE FOR MOST OF THE DAY AND THEN DISSIPATE DURING THE EVENING HOURS TOMORROW...RESULTING IN CLEAR SKIES TOMORROW EVENING. GOING TO HAVE AC AT 8-9KFT. WINDS WILL BE EASTERLY OVERNIGHT AND THEN BECOME SOUTHEAST IN THE MORNING PRIOR TO THE FRONT MOVING NORTH OF THE SITES...THEN SOUTHWEST DURING THE LATE MORNING TO AFTERNOON AFTER THE FRONT MOVES NORTH. WIND SPEEDS WILL INCREASE TOMORROW BEHIND THE FRONT AS GRADIENT TIGHTENS AHEAD OF THE COLD FRONT...THEN DECREASE AROUND SUNSET. AUTEN && .FIRE WEATHER... ISSUED 300 AM CDT WED JUL 25 2012 HAVE CONCERNS WITH RED FLAG POTENTIAL FOR THIS AFTERNOON. DEEP MIXING SHOULD ALLOW DEW POINTS TO FALL INTO THE LOWER 60S ACROSS A GOOD PORTION OF THE CWA THIS AFTERNOON. WITH THE BRUTAL TEMPERATURES EXPECTED...THIS LEVEL OF MIXING WOULD DROP HUMIDITY VALUES INTO THE 20-25 PERCENT RANGE THIS AFTERNOON. MAIN ISSUE IS THAT WINDS WILL BE A BIT BORDERLINE. SURFACE WIND GUSTS AROUND 25 MPH WILL BE POSSIBLE ACROSS PRIMARILY AREAS WEST OF I-55 BY THIS AFTERNOON...BUT 20-FOOT SUSTAINED WINDS WILL BE CLOSER TO 15 MPH... JUST SHY OF CRITERIA. WILL CONTINUE THE SPECIAL WEATHER STATEMENT TO HIGHLIGHT THE FIRE DANGER...AND CONTINUE TO MONITOR FOR ANY POTENTIAL NEED FOR A RED FLAG WARNING. GEELHART && .CLIMATE... ISSUED 300 AM CDT WED JUL 25 2012 RECORD HIGH TEMPERATURES FOR TODAY... BLOOMINGTON...... 106/1934 CHAMPAIGN........ 104/1934 CHARLESTON....... 105/1934 DECATUR.......... 104/1934 JACKSONVILLE..... 108/1934 LINCOLN.......... 105/1934 OLNEY............ 103/1940 PALESTINE........ 103/1901 PEORIA........... 104/1930 SPRINGFIELD...... 103/1936 GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ036-040>042- 047>057-061>063-066>068-071>073. HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR ILZ027>031-037-038-043>046. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
420 AM CDT WED JUL 25 2012 ...UPDATED SYNOPSIS AND SHORT TERM SECTIONS... .SYNOPSIS... ISSUED AT 418 AM CDT WED JUL 25 2012 AN INTENSE UPPER LOW OVER THE SOUTHERN CANADIAN PRAIRIES CONTINUED TO MOVE SLOWLY EAST DURING THE OVERNIGHT HOURS. THERE WERE TWO LOWS EVIDENT AT 850MB IN THE 25.00Z ANALYSIS. THE NORTHERN LOW WAS WELL INTO CANADA NEAR SASKATOON, SASKATCHEWAN. FARTHER SOUTH IN THE CONUS...A LOW WAS CENTERED EAST OF THE BLACK HILLS OF SOUTH DAKOTA. A FAIRLY INTENSE TEMPERATURE GRADIENT WAS NOTED ACROSS SOUTH DAKOTA WITH +20C AT BISMARCK, ND AND +31C NOSING INTO SOUTH CENTRAL SD PER THE RAP ANALYSIS. SEVERAL CLUSTERS OF THUNDERSTORMS DEVELOPED ACROSS SOUTH DAKOTA ALONG THIS BAROCLINIC ZONE, WITH A LARGE MCS ROLLING ACROSS NORTHERN MINNESOTA AS OF 08Z. ELSEWHERE...A SUBTLE BUT IMPORTANT SHORTWAVE TROUGH COULD BE PICKED OUT IN THE RAP ANALYSIS AND WATER VAPOR IMAGERY MOVING EAST THROUGH UTAH AND SOUTHWESTERN WYOMING...MOVING INTO WESTERN/NORTHWESTERN COLORADO. A SURFACE COLD FRONT AS OF 08Z EXTENDED FROM NORTH CENTRAL NEBRASKA TO NORTHEASTERN COLORADO. SURFACE WINDS BEHIND THE FRONT IN EASTERN COLORADO AND THE NEBRASKA PANHANDLE WERE NORTHWEST 20 TO 25 KNOTS WITH SOME GUSTS IN SOME PLACES EXCEEDING 30 KNOTS. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 418 AM CDT WED JUL 25 2012 THE MAIN CHALLENGE IN THE FORECAST PERTAINS TO THUNDERSTORM CHANCES, STRENGTH, AND LOCATION OF THOSE BEST CHANCES LATER ON THIS AFTERNOON AND TONIGHT AS THE COLD FRONT REACHES SOUTHWEST KANSAS. 850MB TEMPS AHEAD OF THE FRONT UP TO +31C SUGGEST ANOTHER DAY OF HIGHS IN THE 103 TO 106F RANGE WITH THE NORTHERN FORECAST AREA SEEING THE HOTTEST TEMPERATURES AGAIN...MUCH LIKE THE PAST FEW DAYS. IF THE STORMS HOLD OFF LONG ENOUGH...HAYS COULD REACH 108F AGAIN LIKE YESTERDAY. INITIAL THUNDERSTORMS SHOULD DEVELOP AS SURFACE TEMPERATURES APPROACH CONVECTIVE TEMPERATURE ALONG AN AXIS FROM ROUGHLY ELKHART TO SYRACUSE TO WAKEENEY-GOVE AREAS. OTHER STORMS MAY FORM FARTHER EAST TIED TO A WEAK MID LEVEL VORTICITY ANOMALY THAT WILL MOVE SLOWLY EAST ACROSS SOUTHWEST KANSAS DURING THE AFTERNOON. THESE STORMS SHOULD BE ALL THAT STRONG SINCE LOW LEVEL CONVERGENCE WILL BE ESSENTIALLY NON-EXISTENT (REMAINING FARTHER NORTH). THE MOST ORGANIZED THUNDERSTORMS WILL DEVELOP IN THE 22-00Z TIME FRAME FROM ROUGHLY LAKIN TO SCOTT CITY TO WAKEENEY. THESE STORMS WILL ADVANCE SLOWLY SOUTHEAST THROUGH THE EVENING HOURS WITH SUBSEQUENT DEVELOPMENT OF STORMS FORMING ON VARIOUS COLD POOL INTERACTIONS WHICH ARE IMPOSSIBLE TO PREDICT. IT IS UNCLEAR WHETHER A SMALL MCS MAY DEVELOP AND THRIVE PAST THE ~04Z TIME FRAME...AS LOW LEVEL MOISTURE, WHILE ADEQUATE IN THE UPPER 50S TO LOWER 60S...WILL NOT BE NEAR WHAT THE GFS MODEL IS SUGGESTING (A CHRONIC PROBLEM WITH THIS MODEL ALL SEASON). THE SHORTWAVE TROUGH MENTIONED IN THE SYNOPSIS SECTION ENTERING COLORADO WILL AID IN SOME INCREASED DEEP UPWARD VERTICAL MOTION LATE TONIGHT...BUT BY THE TIME THAT REACHES WESTERN KANSAS...MUCH OF THE CONVECTIVE ACTIVITY WILL LIKELY HAVE SHIFTED EAST INTO CENTRAL KANSAS. AS FAR AS THE POP FORECAST GOES...WILL BE INCREASING THE POPS TO 50-60 PERCENT NORTH OF A GARDEN CITY TO LARNED LINE TO INTERSTATE 70 CORRIDOR. AS FAR AS THE SEVERE WEATHER POTENTIAL GOES...THERE IS DEFINITELY A CHANCE AT AT LEAST SOME ISOLATED SEVERE WIND REPORTS GIVEN THE SIGNIFICANT TEMPERATURE-DEWPOINT SPREADS. STRONG UPDRAFTS ARE QUITE LIKELY GIVEN THE STRONG LOW LEVEL CONVERGENCE WITH THE SLOW MOVING FRONT. THIS WILL LEAD TO INTENSE DOWNDRAFTS AND EVEN A FEW SEVERE MICROBURSTS. THE HAIL THREAT IS RATHER LOW CONSIDERING THE POOR VERTICAL WIND SHEAR AND OVERALL WARM MID LEVEL TEMPERATURES AS WELL AS HIGH MELTING AND -20C LEVELS. WILL BE DECREASING POPS ACROSS MUCH OF THE FORECAST AREA DURING THE 06-12Z TIME FRAME WITH COLD ADVECTION TAKING OVER IN THE LOW LEVELS AS THE SYNOPTIC FRONT CONTINUES SOUTHEAST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 234 AM CDT WED JUL 25 2012 MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE DEVELOPING ACROSS THE FAR INTERMOUNTAIN WEST TODAY AND DRIFTING SLOWLY EAST ACROSS THE ROCKIES TO BEGIN THE PERIOD THURSDAY. IT WILL MOVE FURTHER INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND QUICKLY BRINGING A GENERALLY DRIER WEATHER PATTERN BACK TO WESTERN KANSAS DURING MUCH OF THE PERIOD. AIDING THIS DRIER PATTERN WILL BE A FAIRLY WEAK FLOW ALOFT ASSOCIATED WITH THE UPPER LEVEL RIDGING. TEMPERATURES ARE EXPECTED TO BE MORE SEASONAL THURSDAY IN WAKE OF A COLD FRONTAL PASSAGE LATE WEDNESDAY. A NORTH TO NORTHEAST LOW LEVEL FLOW WILL PREVAIL ACROSS WESTERN KANSAS THURSDAY HELPING TO LOWER H85 TEMPERATURES EVER SO SLIGHTLY WITH VALUES GENERALLY RANGING FROM THE MID 20S(C) ACROSS CENTRAL KANSAS TO THE UPPER 20S(C) IN EXTREME SOUTHWEST KANSAS. LOOK FOR HIGHS ONLY UP INTO THE 90S(F) THURSDAY AFTERNOON. A GRADUAL WARMING TREND IS STILL EXPECTED INTO THE WEEKEND AS THE AFOREMENTIONED UPPER LEVEL RIDGING APPROACHES FROM THE INTERMOUNTAIN WEST BY THURSDAY AND BEGINS TO PUSH EAST INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND. SHOULD SEE HIGHS CLIMBING UP NEAR TO JUST ABOVE 100F BY THE CLOSE OF THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1242 AM CDT WED JUL 25 2012 THE FIRST COLD FRONT IN QUITE AWHILE WILL BE MOVING THROUGH SOUTHWESTERN KANSAS LATE TOMORROW AND TOMORROW NIGHT. THUNDERSTORMS WILL DEVELOP ALONG THE FRONT DURING THE LATE AFTERNOON AND INTO THE EVENING HOURS. WILL CARRY VICINITY THUNDER IN THE 06Z TAF AT ALL TERMINALS (DDC, GCK, HYS) FROM ROUGHLY 23Z TO 03Z OR SO...ALTHOUGH THUNDERSTORMS WILL PROBABLY NOT AFFECT TERMINALS DURING THE ENTIRE TIME FRAME AS NOTED IN THE TAF. THERE IS SOME MICROBURST POTENTIAL WITH THE STRONGEST STORMS DURING THIS TIME FRAME WITH SUDDEN AND SIGNIFICANT WIND SHIFTS POSSIBLE...EVEN AWAY FROM THUNDERSTORMS AS COLD POOLS SPREAD OUT AWAY FROM THE STORMS. EVENTUALLY ONCE THE CONVECTIVE ACTIVITY CEASES LATER IN THE EVENING...A NORTHWEST WIND WILL PREVAIL AROUND 12 TO 15 KNOTS. && .PRELIMINARY POINT TEMPS/POPS... DDC 104 69 96 67 / 30 40 10 0 GCK 103 67 95 66 / 40 50 10 0 EHA 102 67 93 67 / 30 30 10 0 LBL 104 68 95 67 / 30 30 10 0 HYS 106 68 95 67 / 30 60 10 0 P28 103 74 98 71 / 10 40 20 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...JJOHNSON AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS JACKSON KY
248 AM EDT WED JUL 25 2012 .UPDATE... ISSUED AT 112 AM EDT WED JUL 25 2012 HAVE SENT A COUPLE OF GRID UPDATES ALREADY ON THIS OVERNIGHT SHIFT... FOR THE PURPOSE OF ADDING AND RAISING POPS FOR THE OVERNIGHT PERIOD. SHOWERS AND THUNDERSTORMS HAVE QUICKLY DEVELOPED SINCE ABOUT 11 PM. THE 00Z NAM SEEMS TO HAVE THE BEST HANDLE ON THE SITUATION...ALTHOUGH IT APPEARS TO BE SLIGHTLY TOO FAR WEST WITH ITS AXIS OF HEAVIEST PRECIP. WITH TRAINING THAT IS TAKING PLACE...HAVE SOME CONCERNS ABOUT EXCESSIVE RAINFALL...ESPECIALLY SINCE IT IS OCCURRING IN AREAS WHICH ALREADY HAD SUBSTANTIAL RAIN DURING THE DAY ON TUESDAY. UPDATE ISSUED AT 950 PM EDT TUE JUL 24 2012 UPDATED THE FORECAST TO DROP THE SOUTHERN WATCH BOX AND EFFECTIVELY REMOVE POPS FOR MOST OF THE NIGHT DOWN THERE. OTHERWISE...ADJUSTED THE SKY COVER...TEMPS...AND DEW POINTS FOR CURRENT OBS AND TRENDS. THE ONLY FLY IN THE OINTMENT FOR A QUIET REST OF THE NIGHT WILL BE THE SEVERE THUNDERSTORM HEADING EAST...JUST NORTH OF INTERSTATE 64...ACROSS CENTRAL KENTUCKY. SHOULD THIS...AND ANY OF ITS TRAILING CONVECTION TO THE WEST...HOLD TOGETHER...DESPITE LOWER INSTABILITY AND A MORE WORKED OVER ENVIRONMENT HERE IN THE EAST...IT COULD MAKE IT INTO THE CWA AROUND MIDNIGHT. FOR NOW HAVE PAINTED IT AS DISSIPATING ON OUR FRINGES...BUT IT HAS BEEN GOING STRONG FOR OVER AN HOUR NOW. WILL RE-EXAMINE IN AN HOUR OR SO...SHOULD IT STILL BE INTACT. UPDATES HAVE BEEN ISSUED TO THE ZONES...NDFD GRIDS...AND WEB. UPDATE ISSUED AT 815 PM EDT TUE JUL 24 2012 UPDATED THE GRIDS TO REFLECT THE DIMINISHING THREAT OF SEVERE WEATHER OR ANY FURTHER CONVECTION IN OUR FAR SOUTHERN COUNTIES. HOWEVER... WILL HOLD OFF ON DROPPING THE BOX FOR ANOTHER HALF HOUR OR SO JUST TO BE SURE THAT SOME BOUNDARY FROM THE WEST DOESN/T KICK OFF ANY STORMS ALONG OUR BORDER REGION. THE BULK OF OUR AREA HAS NOW BEEN WORKED OVER AND INSTABILITY IS FALLING SO THE ONLY THREAT ARE REMAINS IN THE FAR SOUTHWEST. HOWEVER...WOULD NOT RULE OUT SOME REDEVELOPMENT ALONG THE STALLED BOUNDARY LATER TONIGHT OR EVEN A BATCH OF CONVECTION DROPPING DOWN FROM THE NORTH TOWARDS DAWN. HAVE KEPT THESE IDEAS GOING FROM THE PREVIOUS SHIFT. IN ADDITION...PATCHES TO AREAS OF FOG ARE ALSO ANTICIPATED THROUGH MUCH OF THE AREA BY DAWN...BECOMING LOCALLY DENSE. THE FORECAST HAS THIS HANDLED WELL SO NOT ADJUSTMENTS NEEDED HERE. DID ALSO TWEAK SKY COVER...TEMPS AND DEW POINTS FOR THE CURRENT OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE NDFD GRIDS AND THE WEB. UPDATE ISSUED AT 633 PM EDT TUE JUL 24 2012 WITH A MUGGY AND UNSTABLE AIR MASS STILL IN PLACE ACROSS THE SOUTHWEST ZONES...SPC HAS ISSUED A NEW SEVERE THUNDERSTORM WATCH UNTIL 11 PM. ONLY A FEW STORMS AFFECTING THE AREA PRESENTLY...BUT WE COULD STILL SEE SOME NEW DEVELOPMENT THIS EVENING. MEANWHILE...QUIET CONDITIONS ACROSS A GOOD CHUNK OF EASTERN KENTUCKY WILL LIKELY STAY THAT WAY THROUGH MUCH OF TONIGHT. THUS...POPS HAVE BEEN REMOVED OR LOWERED ACROSS THE BOARD. ALSO...WITH TEMPERATURES ALREADY ON THE COOL SIDE AND RECENT RAINFALL...WE MAY SEE SOME PATCHY FOG OVERNIGHT. ZONE UPDATE IS ALREADY OUT. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 339 PM EDT TUE JUL 24 2012 IMMEDIATE SHORT TERM ISSUES REVOLVE AROUND THE ONGOING WATCH. WITH MORE OF THE ACTIVITY SHIFTING SOUTHWARD...GOING TO CLEAR MORE COUNTIES OUT OF EASTERN KENTUCKY OVER THE NEXT HOUR. MEANWHILE...STILL WATCHING AN OUTFLOW BOUNDARY...FROM CENTRAL ESTILL COUNTY...SOUTHEAST INTO SOUTHERN BREATHITT COUNTY. THIS BOUNDARY COULD TRIGGER ADDITIONAL STORMS AS IT SINKS SOUTHWARD THIS EVENING. THUS...THE WATCH WILL CONTINUE ACROSS OUR SOUTHWEST COUNTIES UNTIL THIS BOUNDARY PUSHES ACROSS THIS AREA. THE HRRR CONTINUES TO SHOW NEW DEVELOPMENT...BUT THUS FAR...HAVE NOT SEEN ANY DEVELOPMENT ALONG THIS BOUNDARY. AS THIS BOUNDARY AND COMPLEX OF STORMS EXITS TO THE SOUTH THIS EVENING...THERE WILL LIKELY BE A TEMPORARY BREAK FROM THE CONVECTION. HOWEVER...ANOTHER WEAK WAVE IS POISED TO DROP SOUTHWARD OVERNIGHT AND COULD GENERATE MORE SHOWERS AND THUNDERSTORMS. WITH LITTLE ACTIVITY UPSTREAM PRESENTLY...OPTING TO KEEP POPS ON THE LOWER SIDE UNTIL BETTER CONFIDENCE CAN BE OBTAINED. A NORTH/SOUTH BOUNDARY WILL THEN SET UP OVER FAR EASTERN KENTUCKY THROUGH TOMORROW AFTERNOON AND EVENING. THIS WILL KEEP UNSETTLED WEATHER IN THE FORECAST THROUGH WEDNESDAY EVENING AS DAYTIME INSTABILITY WILL ONCE AGAIN FUEL STORM DEVELOPMENT...ESPECIALLY OVER SOUTHEAST AND FAR EASTERN KENTUCKY. THE FURTHER WEST YOU GO AWAY FROM THE BOUNDARY...THE MORE LIKELIHOOD TO MISS OUT ON ANY STORMS TOMORROW. BASED ON THE WEAK STORM MOVEMENT TOMORROW AFTERNOON...WE MAY HAVE TO WATCH FOR TRAINING STORMS AND FLASH FLOODING POTENTIAL. PWS WILL STILL BE CLOSE TO 2 INCHES TOMORROW...SO CLEARLY GOING TO HAVE TO KEEP AN EYE ON THE FLOODING POTENTIAL. WE MAY NEED A FLASH FLOOD WATCH...BUT WILL LET THE MIDNIGHT SHIFT REEVALUATE. THIS BOUNDARY WILL EVENTUALLY DEPART TO THE NORTHEAST TOMORROW NIGHT...TAKING THE THREAT OF PRECIPITATION WITH IT AND PUTTING THE AREA UNDER STRONGER INFLUENCE OF THE HIGH. MILD CONDITIONS WILL CONTINUE WITH HIGHS ON WEDNESDAY WELL INTO THE 80S...AND LOWS TONIGHT AND WEDNESDAY NIGHT IN THE LOWER 70S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 339 PM EDT TUE JUL 24 2012 THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN. THURSDAY STARTS OUT WITH A UPPER LOW OVER MINNESOTA WITH A TROUGH EXTENDING SOUTH ALONG THE I35 CORRIDOR. THE TROUGH WILL MOVE TO THE EAST AND WILL PASS EASTERN KENTUCKY ON FRIDAY NIGHT/SATURDAY MORNING TIME FRAME. THE TROUGH WILL FINALLY PUSH A LINGERING COLD FRONT SOUTH AND EAST OF THE AREA ON FRIDAY. THIS WILL HELP TO BRING SOME COOLER AND DRIER AIR INTO THE AREA. WITH THE MODELS IN SUCH GOOD AGREEMENT...RELIED VERY HEAVILY ON THE MODEL BLEND FOR ALL FIELDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 248 AM EDT WED JUL 25 2012 SHOWERS AND THUNDERSTORMS WERE ONGOING OVER THE NORTHERN AND EASTERN PORTIONS OF THE FORECAST AREA AT THE START OF THE PERIOD...WITH LOCALIZED IFR. THE AREA OF PRECIP WILL TRANSLATE TOWARD THE SE OVERNIGHT...AND SHOULD MOSTLY BE OUT OF THE AREA BY 12Z. HOWEVER...FOG WILL OCCUR...ESPECIALLY IN VALLEYS WHERE RAIN FELL...AND WILL BRING LOCALIZED IFR UNTIL A LITTLE PAST SUNRISE. A RELATIVE LULL IN PRECIP IS EXPECTED ON WEDNESDAY MORNING...WITH MOSTLY VFR OUTSIDE OF EARLY MORNING FOG. HOWEVER...ADDITIONAL THUNDERSTORMS ARE LIKELY TO DEVELOP IN THE AFTERNOON...ESPECIALLY NEAR THE WV AND VA BORDERS. THESE SHOULD DIMINISH TOWARD SUNSET. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...KAS LONG TERM....JJ AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
112 AM EDT WED JUL 25 2012 .UPDATE... ISSUED AT 112 AM EDT WED JUL 25 2012 HAVE SENT A COUPLE OF GRID UPDATES ALREADY ON THIS OVERNIGHT SHIFT... FOR THE PURPOSE OF ADDING AND RAISING POPS FOR THE OVERNIGHT PERIOD. SHOWERS AND THUNDERSTORMS HAVE QUICKLY DEVELOPED SINCE ABOUT 11 PM. THE 00Z NAM SEEMS TO HAVE THE BEST HANDLE ON THE SITUATION...ALTHOUGH IT APPEARS TO BE SLIGHTLY TOO FAR WEST WITH ITS AXIS OF HEAVIEST PRECIP. WITH TRAINING THAT IS TAKING PLACE...HAVE SOME CONCERNS ABOUT EXCESSIVE RAINFALL...ESPECIALLY SINCE IT IS OCCURRING IN AREAS WHICH ALREADY HAD SUBSTANTIAL RAIN DURING THE DAY ON TUESDAY. UPDATE ISSUED AT 950 PM EDT TUE JUL 24 2012 UPDATED THE FORECAST TO DROP THE SOUTHERN WATCH BOX AND EFFECTIVELY REMOVE POPS FOR MOST OF THE NIGHT DOWN THERE. OTHERWISE...ADJUSTED THE SKY COVER...TEMPS...AND DEW POINTS FOR CURRENT OBS AND TRENDS. THE ONLY FLY IN THE OINTMENT FOR A QUIET REST OF THE NIGHT WILL BE THE SEVERE THUNDERSTORM HEADING EAST...JUST NORTH OF INTERSTATE 64...ACROSS CENTRAL KENTUCKY. SHOULD THIS...AND ANY OF ITS TRAILING CONVECTION TO THE WEST...HOLD TOGETHER...DESPITE LOWER INSTABILITY AND A MORE WORKED OVER ENVIRONMENT HERE IN THE EAST...IT COULD MAKE IT INTO THE CWA AROUND MIDNIGHT. FOR NOW HAVE PAINTED IT AS DISSIPATING ON OUR FRINGES...BUT IT HAS BEEN GOING STRONG FOR OVER AN HOUR NOW. WILL RE-EXAMINE IN AN HOUR OR SO...SHOULD IT STILL BE INTACT. UPDATES HAVE BEEN ISSUED TO THE ZONES...NDFD GRIDS...AND WEB. UPDATE ISSUED AT 815 PM EDT TUE JUL 24 2012 UPDATED THE GRIDS TO REFLECT THE DIMINISHING THREAT OF SEVERE WEATHER OR ANY FURTHER CONVECTION IN OUR FAR SOUTHERN COUNTIES. HOWEVER... WILL HOLD OFF ON DROPPING THE BOX FOR ANOTHER HALF HOUR OR SO JUST TO BE SURE THAT SOME BOUNDARY FROM THE WEST DOESN/T KICK OFF ANY STORMS ALONG OUR BORDER REGION. THE BULK OF OUR AREA HAS NOW BEEN WORKED OVER AND INSTABILITY IS FALLING SO THE ONLY THREAT ARE REMAINS IN THE FAR SOUTHWEST. HOWEVER...WOULD NOT RULE OUT SOME REDEVELOPMENT ALONG THE STALLED BOUNDARY LATER TONIGHT OR EVEN A BATCH OF CONVECTION DROPPING DOWN FROM THE NORTH TOWARDS DAWN. HAVE KEPT THESE IDEAS GOING FROM THE PREVIOUS SHIFT. IN ADDITION...PATCHES TO AREAS OF FOG ARE ALSO ANTICIPATED THROUGH MUCH OF THE AREA BY DAWN...BECOMING LOCALLY DENSE. THE FORECAST HAS THIS HANDLED WELL SO NOT ADJUSTMENTS NEEDED HERE. DID ALSO TWEAK SKY COVER...TEMPS AND DEW POINTS FOR THE CURRENT OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE NDFD GRIDS AND THE WEB. UPDATE ISSUED AT 633 PM EDT TUE JUL 24 2012 WITH A MUGGY AND UNSTABLE AIR MASS STILL IN PLACE ACROSS THE SOUTHWEST ZONES...SPC HAS ISSUED A NEW SEVERE THUNDERSTORM WATCH UNTIL 11 PM. ONLY A FEW STORMS AFFECTING THE AREA PRESENTLY...BUT WE COULD STILL SEE SOME NEW DEVELOPMENT THIS EVENING. MEANWHILE...QUIET CONDITIONS ACROSS A GOOD CHUNK OF EASTERN KENTUCKY WILL LIKELY STAY THAT WAY THROUGH MUCH OF TONIGHT. THUS...POPS HAVE BEEN REMOVED OR LOWERED ACROSS THE BOARD. ALSO...WITH TEMPERATURES ALREADY ON THE COOL SIDE AND RECENT RAINFALL...WE MAY SEE SOME PATCHY FOG OVERNIGHT. ZONE UPDATE IS ALREADY OUT. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 339 PM EDT TUE JUL 24 2012 IMMEDIATE SHORT TERM ISSUES REVOLVE AROUND THE ONGOING WATCH. WITH MORE OF THE ACTIVITY SHIFTING SOUTHWARD...GOING TO CLEAR MORE COUNTIES OUT OF EASTERN KENTUCKY OVER THE NEXT HOUR. MEANWHILE...STILL WATCHING AN OUTFLOW BOUNDARY...FROM CENTRAL ESTILL COUNTY...SOUTHEAST INTO SOUTHERN BREATHITT COUNTY. THIS BOUNDARY COULD TRIGGER ADDITIONAL STORMS AS IT SINKS SOUTHWARD THIS EVENING. THUS...THE WATCH WILL CONTINUE ACROSS OUR SOUTHWEST COUNTIES UNTIL THIS BOUNDARY PUSHES ACROSS THIS AREA. THE HRRR CONTINUES TO SHOW NEW DEVELOPMENT...BUT THUS FAR...HAVE NOT SEEN ANY DEVELOPMENT ALONG THIS BOUNDARY. AS THIS BOUNDARY AND COMPLEX OF STORMS EXITS TO THE SOUTH THIS EVENING...THERE WILL LIKELY BE A TEMPORARY BREAK FROM THE CONVECTION. HOWEVER...ANOTHER WEAK WAVE IS POISED TO DROP SOUTHWARD OVERNIGHT AND COULD GENERATE MORE SHOWERS AND THUNDERSTORMS. WITH LITTLE ACTIVITY UPSTREAM PRESENTLY...OPTING TO KEEP POPS ON THE LOWER SIDE UNTIL BETTER CONFIDENCE CAN BE OBTAINED. A NORTH/SOUTH BOUNDARY WILL THEN SET UP OVER FAR EASTERN KENTUCKY THROUGH TOMORROW AFTERNOON AND EVENING. THIS WILL KEEP UNSETTLED WEATHER IN THE FORECAST THROUGH WEDNESDAY EVENING AS DAYTIME INSTABILITY WILL ONCE AGAIN FUEL STORM DEVELOPMENT...ESPECIALLY OVER SOUTHEAST AND FAR EASTERN KENTUCKY. THE FURTHER WEST YOU GO AWAY FROM THE BOUNDARY...THE MORE LIKELIHOOD TO MISS OUT ON ANY STORMS TOMORROW. BASED ON THE WEAK STORM MOVEMENT TOMORROW AFTERNOON...WE MAY HAVE TO WATCH FOR TRAINING STORMS AND FLASH FLOODING POTENTIAL. PWS WILL STILL BE CLOSE TO 2 INCHES TOMORROW...SO CLEARLY GOING TO HAVE TO KEEP AN EYE ON THE FLOODING POTENTIAL. WE MAY NEED A FLASH FLOOD WATCH...BUT WILL LET THE MIDNIGHT SHIFT REEVALUATE. THIS BOUNDARY WILL EVENTUALLY DEPART TO THE NORTHEAST TOMORROW NIGHT...TAKING THE THREAT OF PRECIPITATION WITH IT AND PUTTING THE AREA UNDER STRONGER INFLUENCE OF THE HIGH. MILD CONDITIONS WILL CONTINUE WITH HIGHS ON WEDNESDAY WELL INTO THE 80S...AND LOWS TONIGHT AND WEDNESDAY NIGHT IN THE LOWER 70S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 339 PM EDT TUE JUL 24 2012 THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN. THURSDAY STARTS OUT WITH A UPPER LOW OVER MINNESOTA WITH A TROUGH EXTENDING SOUTH ALONG THE I35 CORRIDOR. THE TROUGH WILL MOVE TO THE EAST AND WILL PASS EASTERN KENTUCKY ON FRIDAY NIGHT/SATURDAY MORNING TIME FRAME. THE TROUGH WILL FINALLY PUSH A LINGERING COLD FRONT SOUTH AND EAST OF THE AREA ON FRIDAY. THIS WILL HELP TO BRING SOME COOLER AND DRIER AIR INTO THE AREA. WITH THE MODELS IN SUCH GOOD AGREEMENT...RELIED VERY HEAVILY ON THE MODEL BLEND FOR ALL FIELDS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 815 PM EDT TUE JUL 24 2012 THE BULK OF THE CONVECTION HAS NOW FADED THROUGH THE AREA AND SHOULD NOT BE A FACTOR IN THE TAFS THROUGH THE REMAINDER OF THE NIGHT. HOWEVER...PATCHY DENSE FOG WILL BE A THREAT TONIGHT...ESPECIALLY IN VALLEY LOCATIONS. LEFT FOG IN FOR THE TAF STATIONS...THOUGH IT WILL LIKELY BE DEPENDENT ON WHICH AIRPORTS SAW PCPN AT OR NEAR THAT PARTICULAR LOCATION. FOR WEDNESDAY...SCATTERED STORMS ARE AGAIN ANTICIPATED TO DEVELOP BY MID AFTERNOON...MAINLY OVER FAR EASTERN KENTUCKY. HAVE ADDED A VCTS FOR THIS AT JKL BUT LEFT LOZ AND SME CLEAN. WINDS WILL BE LIGHT AND VARIABLE FOR THE MOST PART THROUGH THE TAF PERIOD WITH SOME BREEZES UP TOWARD 5 AND 10 KTS POSSIBLE... GENERALLY FROM THE SOUTHWEST...AROUND PEAK HEATING WEDNESDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...KAS LONG TERM....JJ AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
444 AM EDT WED JUL 25 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED JUL 25 2012 ACTIVE WEATHER MORNING AS COMPLEX OF THUNDERSTORMS THAT HAS FORMED OVR NORTHERN MN IS POISED TO IMPACT MUCH OF CWA THROUGH AT LEAST EARLY AFTN. TSRA OVR WCNTRL INTO NORTHERN MN DEVELOPED IN AREA OF PVA FM SHORTWAVE LIFTING INTO NORTHERN MN AND WAS ALSO TIED TO H85-H7 MOISTURE ADVECTION/H7 FGEN AND RIGHT ENTRANCE JET FORCING/ISENTROPIC LIFT ON 300-305K SFC. COMPLEX IS WELL TO NORTH OF SFC WARM FRONT...MORE IN LINE WITH NORTHERN GRADIENT OF MLCAPE OVR 2000 J/KG AND WITHIN AREA OF SUFFICIENT DEEP LAYER SHEAR OVR 40 KTS. 0-1KM SHEAR TO 40 KTS HAS ALLOWED COLD POOLS TO DEVELOP AND BRIEFLY PROPAGATE EASTWARD. MOST WIND GUSTS WITH ACTIVITY HAVE BEEN IN THE 30-40 KT RANGE. COMPLEX WILL CONTINUE EASTWARD BUT MAY LOSE SOME PUNCH AS IT STRAYS AWAY FM GRADIENT OF MLCAPE. H85-H3 THICKNESSES SUGGEST ANY STONGER LINEAR SEGMENTS MAY TRY TO DRIFT ESE AS THE COMPLEX PUSHES NEAR IWD WITHIN THE NEXT 2-3 HRS. NO REAL BIG CHANGE TO PREVIOUS FCST...THOUGH THAT IS PARTIALLY DUE TO A LOT OF SCENARIOS OFFERED UP BY VARIOUS GUIDANCE ON HOW THIS COMPLEX WILL TRANSLATE TO THE EAST THE NEXT FEW HOURS. WENT WITH A CONSENSUS FM ALL THE SOLUTIONS ALONG WITH PREVIOUS FCST. OVERALL FEEL FAIRLY CONFIDENT THAT BTWN ONGOING/STRONG H85 MOISTURE TRANSPORT ON NOSE OF H85 JET AND DIVERGENCE ALOFT...THAT THE OVERALL COMPLEX WILL CONTINUE TO TRACK ON A GENERAL EASTWARD MOVEMENT ACROSS UPR MICHIGAN THROUGH EARLY AFTN...ON SOUTH EDGE OF SHORTWAVE MOVING ACROSS NORTHERN LK SUPERIOR AND STILL WELL TO NORTH OF SFC WARM FRONT. LATEST RENDITION OF RAPID REFRESH RUC /HRRR/ SHOWS THIS PRETTY WELL AND INDICATES THAT MAJORITY OF PRECIP WILL BE DONE BY EARLY AFTN OVR WEST HALF AND SOON THERE AFTER IN THE EAST. WHAT HAPPENS BY MID TO LATE AFTN IS A CONCERN AS MODELS HAVE CERTAINLY TRENDED FARTHER NORTH WITH ADVANCING SFC WARM FRONT BY MID-LATE AFTN. SINCE IT APPEARS NOW THAT BULK OF CONVECTIVE COMPLEX THIS MORNING WILL JUST GRAZE SOUTHERN CWA IT IS MORE FEASIBLE THAT SOUTHERN CWA MAY SNEAK INTO WARM SECTOR THIS AFTN AND WITH GRADIENT OF 0-6KM MUCAPE WELL OVR 2000 J/KG OVERHEAD ALONG WITH ANOTHER SHORTWAVE WORKING THROUGH IN SPEEDY WESTERLY FLOW IN ADDITION TO MORE UPPER DIVERGENCE ALOFT...BEGINNING TO THINK AN ADDITIONAL ROUND OF SHRA/TSRA MAY DEVELOP BY LATE AFTN. IF CONVECTION BEHAVES LIKE IT HAS OVERNIGHT WITH MOST ACTIVITY OCCURRING ON GRADIENT OF MLCAPE...THEN PORTIONS OF CWA WOULD BE FAVORED FOR STRONG TSRA LINE SEGMENTS WITH STRONG/GUSTY WINDS. A LOT WILL DEPEND ON HOW QUICKLY COMPLEX MOVES THROUGH TODAY AND EXTENT OF DESTABILIZATION THAT CAN OCCUR LATE TODAY. THREAT FOR STORMS COULD LINGER INTO THE EVENING. LATER TONIGHT...STRONG UPPER LOW CURRENTLY OVR SOUTHERN SASKATCHEWAN WILL BE APPROACHING. H7-H3 Q-VECTOR CONVERGENCE AHEAD OF UPR LOW COULD TRIGGER ELEVATED CONVECTION. TROUBLE IS MOISTURE IS HEAVY IN THE LOW-LEVELS BUT REALLY DRYING OUT IN THE MID-UPR LEVELS. KEPT SOME SLIGHT CHANCES IN FCST BUT BETTER CHANCES LIKELY HOLD OFF TIL AFTER DAYBREAK ON THURSDAY. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 439 AM EDT WED JUL 25 2012 BEGINNING OF THE PERIOD WILL INCLUDE A CLOSED 500MB LOW OVER NORTHERN MN THAT WILL TRACK SOUTHEASTWARD WHILE LOSING STRENGTH...CROSSING THE UPPER GREAT LAKES BY NIGHTFALL. AS IT NEARS...MODEL SOUNDINGS ARE HINTING AT ABUNDANT LEFTOVER MOISTURE FROM WEDNESDAY/S EXITING SYSTEM...SO WILL CONTINUE WITH PREVIOUS FORECASTS MENTION OF CLOUDY SKIES...COOLER CONDITIONS...AND A SLIGHT CHANCE FOR SHRA. THICK CLOUD COVER FROM THE LOW LEVELS UPWARDS WILL PREVENT MUCH IN THE WAY OF RADIATIVE HEATING...SO WILL KEEP TEMPS BELOW NORMAL...BARELY REACHING THE 70 MARK NEAR LAKE SUPERIOR. ALL MODELS SEEM TO BE IN GOOD AGREEMENT OF SOME PRECIP TRAVERSING UPPER MI THURSDAY NIGHT AS A RESULT OF THIS UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE WARM FRONT. THOUGH PWAT VALUES ARE ONLY 100-120 PERCENT OF NORMAL...ABUNDANT LINGERING MOISTURE MENTIONED ABOVE SHOULD BE ENOUGH TO SPARK SOME PRECIP ALONG THE MAIN LINE OF CONVERGENCE/WARM FRONT/ AS IT PASSES OVER. HOWEVER...A PROBLEM PERSISTS ON THE EXACT LOCATION OF THE PRECIP AND CONVERGENCE...AS EVERY MODEL SEEMS TO HAVE A SLIGHTLY DIFFERENT SOLUTION IN WHICH PART OF UPPER MI WILL SEE THE BEST RAINFALL CHANCES THURSDAY NIGHT INTO FRIDAY. LATEST NAM SHOWS BEST MU CAPE VALUES TO ARRIVE WITH THE ONSET OF THE FRONTAL PASSAGE AND DIMINISH DURING THE OVERNIGHT HOURS /BY 03Z/...WITH HIGHEST VALUES /1-1.5 J/KG/ NEAR THE WISCONSIN BORDER. HOWEVER 0-3KM COMPUTED CAPE VALUES ONLY TOP OUT BETWEEN 2-300 J/KG...WITH THE NAM FORECASTED CAPE PROFILE VERY LONG AND SKINNY...INDICATIVE OF ONLY ISOLATED CHANCES. TO SUM UP THEN...A FEW RUMBLES OF THUNDER AND FLASHES OF LIGHTNING COULD BE POSSIBLE DURING THE EVENING WHEN INSTABILITY IS AT ITS BEST...BUT OTHERWISE AM LEANING TOWARDS THIS MAINLY BEING A HEAVY RAIN EVENT. 500MB SHORTWAVE WILL CONTINUE TO WEAKEN AS IT EXITS INTO THE LOWER GREAT LAKES DURING THE DAY FRIDAY. HOWEVER...LINGERING MOISTURE WILL MAKE FOR SIMILAR CONDITIONS TO THURSDAY...WITH THICK CLOUD COVER AND NRLY WINDS MAKING FOR MOIST AND COOLER THAN NORMAL CONDITIONS. MANY LOCATIONS WILL STRUGGLE TO GET INTO THE 70S. WITH THIS SET UP...WILL CONTINUE WITH SLIGHT CHANCE POPS DURING THE DAY FRIDAY IN THE WEST AND CENTRAL...IN THAT SOME LEFT OVER FORCING COULD BE ENOUGH TO SPAWN SOME SHRA/TSRA...WHILE BEST FORCING AND PRECIP CHANCES WILL LIE NEAR LAKE MICHIGAN. 500MB RIDGING PATTERN OVER THE NORTHERN PLAINS WILL BEGIN TO MOVE EASTWARD...WORKING ITS WAY INTO THE WESTERN PORTIONS OF THE CWA BY LATE FRIDAY AFTERNOON AS IS SEEN ON THE FORECAST SOUNDINGS...FIRST STARTING IN THE UPPER LEVELS AND THEN WORKING ITS WAY DOWN TO THE SURFACE. THIS WILL TRANSLATE TO RAPIDLY CLEARING SKIES FROM WEST TO EAST DURING THE OVERNIGHT HOURS AND LOWS DROPPING TO THE LOW TO MID 50S INLAND AWAY FROM THE WARMER LAKE INFLUENCE. 500MB RIDGE AND ASSOCIATED HIGH PRESSURE WILL CONTINUE TO DOMINATE THROUGH THE DAY ON SUNDAY. THIS WILL TRANSLATE TO MOSTLY SUNNY SKIES ACROSS THE REGION...LIGHT SOUTHERLY WINDS...AND HIGH TEMPERATURES RISING TO BACK ABOVE NORMAL. THE 500MB RIDGE SHOULD REMAIN IN PLACE THROUGHOUT THE REST OF THE FORECAST PERIOD...WITH SEVERAL WEAK SHORTWAVES TRAVERSING THE RIDGE AND UPPER GREAT LAKES. ALL LONG RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT SHORTWAVE AND RESULTING PRECIP WILL TRAVERSE THE UPPER GREAT LAKES SUNDAY EVENING INTO MONDAY WITH PW VALUES JUMPING BACK UP TO 100-120 PERCENT OF NORMAL. UNFORTUNATELY...AFTER THIS POINT MODELS START TO LOSE AGREEMENT ON TIMING AND LOCATIONS OF MENTIONED PRECIP SO WENT WITH MODEL CONSENSUS FOR REMAINDER OF FORECAST PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 133 AM EDT WED JUL 25 2012 EXPECT VFR CONDITIONS AT THE START OF THE FCST PERIOD TO GIVE WAY TO SHRA/SOME TS SW-NE EARLY THIS MRNG IN ADVANCE OF WARM FNT...WITH THIS PCPN REACHING CMX/SAW ARND SUNRISE. THE RA COULD BE HEAVY AT TIMES...WITH VSBY LIKELY REDUCED TO AT LEAST MVFR RANGE THRU THE MORNING. MAINTAINED MENTION OF TS AT IWD AS THIS SITE WL BE CLOSER TO GREATER INSTABILITY TO THE S. THERE COULD ALSO BE TS AT SAW/ CMX...BUT WEAKER INSTABILITY FARTHER N OF THE WARM FNT INDICATES THE CHC IS TOO LO TO INCLUDE SPECIFIC MENTION ATTM. ALSO LOWERED CIGS TO MVFR...AND THESE MAY DROP TO IFR...ESPECIALLY AT SAW/CMX WITH GREATER UPSLOPE WIND COMPONENT. THE HEAVIER SHRA WL MOVE OUT ON WED AFTN...WITH IMPROVING VSBY. LO CIGS TO IFR ARE MOST LIKELY AT SAW/ CMX WITH PERSISTENT UPSLOPE WIND COMPONENT/LLVL MSTR LINGERNING N OF SFC WARM FNT. BEST SHOT FOR VFR CIGS THIS AFTN WL BE AT IWD...WITH DOWNSLOPING WIND. BUT EVEN THERE...EXPECT CONDITIONS TO DROP TO IFR/LIFR TNGT WITH LLVL MSTR LINGERING UNDER LGT UPSLOPE WIND COMPONENT OFF LK SUP/SOME MID LVL DRYING IN THE WAKE OF DEPARTING DISTURBANCE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 439 AM EDT WED JUL 25 2012 LOW PRESSURE SYSTEM MOVES INTO WISCONSIN LATER TODAY AND INTO THE EASTERN GREAT LAKES ON THURSDAY MORNING AND INTO THE NEW ENGLAND STATES ON FRIDAY. THIS WILL LEAVE A WEAK SFC TROUGH OVER THE UPPER GREAT LAKES LATER TONIGHT THROUGH FRIDAY. HIGH PRESSURE WILL THEN MOVE OVER THE UPPER GREAT LAKES THIS WEEKEND...LEADING TO LIGHT WINDS OVER LK SUPERIOR. SOME STRONG E/SE WINDS POSSIBLE TODAY OVR EASTERN AND NORTHERN SECTIONS OF LK SUPERIOR OUT AHEAD OF THE LOW MOVING THROUGH AND THEN GUSTY ENE WINDS THIS EVENING IN WAKE OF THE LOW. OVERALL THOUGH...EXPECT WINDS TO STAY BELOW 20KTS THROUGH THE WEEKEND. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLA LONG TERM...JMW AVIATION...KC MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
345 AM EDT WED JUL 25 2012 .SYNOPSIS... ISSUED AT 345 AM EDT WED JUL 25 2012 A WARM FRONT WILL BRING POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY MAINLY NORTH OF INTERSTATE 96 THIS AFTERNOON. IT WILL BECOME HOT AND HUMID LATER TODAY SOUTH OF THE WARM FRONT. STRONG LOW PRESSURE TRACKING EAST ALONG THE WARM FRONT AND AN APPROACHING COLD FRONT WILL COMBINE TO BRING POTENTIAL FOR STRONG TO SEVERE STORMS TONIGHT THAT MAY PRODUCE DAMAGING WIND GUSTS AND HEAVY RAIN. TEMPERATURES WILL RETURN TO CLOSER TO NORMAL BEHIND THAT FRONT THURSDAY AND FRIDAY WITH A CONTINUED CHANCE OF SOME SHOWERS AND STORMS. FAIR WEATHER IS ANTICIPATED THIS WEEKEND. && .SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON) ISSUED AT 345 AM EDT WED JUL 25 2012 OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE TIMING/PROBABILITIES FOR CONVECTION THROUGH THE SHORT TERM FCST PERIOD AND TO ASSESS SEVERE WX POTENTIAL. THE SETUP LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS TONIGHT AS A STRONG LOW PRESSURE WAVE TRACKS EAST ALONG THE WARM FRONT AND COLD FRONT APPROACHES. THERE WILL BE PLENTY OF MOISTURE AND DECENT INSTABILITY ALONG WITH LIFT FROM THE APPROACHING FRONT. DEEP LAYER SHEAR VALUES RAMPING UP TO 35 TO 40 KTS ARE ALSO FAVORABLE FOR ORGANIZED SEVERE STORMS. 00Z 4KM WRF-NMM SIM Z GUIDANCE SHOWS CONVECTIVE DEVELOPMENT ACROSS OUR AREA FROM 00Z THRU 12Z TONIGHT. 00Z 4KM NSSL WRF GUIDANCE ALSO SHOWS POTENTIAL TONIGHT ESPECIALLY OVER OUR NORTHERN COUNTIES WHICH IS ALSO SUPPORTED BY THE 00Z ECMWF. AN ISOLATED TORNADO IS POSSIBLE EARLY TO MID EVENING WITH A SOMEWHAT VEERED WIND PROFILE WITH HEIGHT AND DEEP LAYER SHEAR VALUES CONDUCIVE TO SUPERCELLS. DAMAGING WIND GUSTS SHOULD BE THE MOST LIKELY SEVERE WX THREAT BUT HEAVY RAINFALL IS ALSO POSSIBLE. PRECIPITABLE WATER VALUES WILL REACH 1.75 TO 2.25 INCHES JUST AHEAD OF THE APPROACHING COLD FRONT ALONG WITH DECENT LOW TO MID LEVEL MOISTURE POOLING ALONG/AHEAD OF THE FRONT. THE GREATEST THREAT FOR SVR WX SHOULD COME FROM AROUND 23Z THIS EVE THROUGH 06Z THUR WITH GREATER INSTABILITY IN PLACE THROUGH THE EVENING HOURS AND WITH THE CRAVEN BROOKS SIG SVR PARAMETER UP AROUND 40-50K. THIS IS ALSO THE WINDOW OF TIME THAT THE SUPERCELL COMPOSITE PARAMETER IS FCST TO BE WAY UP AROUND A VALUE OF 12. THE SIG TOR PARAMETER REACHES VALUES OF 1 TO 4 FROM EARLY TO MID EVENING BEFORE DROPPING OFF OVERNIGHT. THE BEST CHC FOR AN ISOLATED TORNADO THIS EVE WOULD BE OVER OUR NORTHERN COUNTIES IN CLOSER PROXIMITY TO THE WARM FRONT WHERE 0-1KM AND 0-3KM SRH VALUES WILL BE ENHANCED. THE THREAT FOR SOME SEVERE STORMS WILL LINGER EVEN AFTER 06Z TONIGHT THROUGH AT LEAST DAYBREAK IF NOT MIDDAY THURSDAY... THE POTENTIAL JUST WILL NOT BE QUITE AS FAVORABLE AS BETWEEN 23Z-06Z TONIGHT AS SUGGESTED BY A CONSENSUS OF SPC SREF SVR WX PARAMETERS. THIS NOTION IS ALSO SUPPORTED BY OUR LOCAL SEVERE WX CLIMATOLOGY. THE FCST FOR THIS MORNING AND AFTERNOON IS TRICKY. MOST OF THE HIGHER RESOLUTION GUIDANCE SUGGESTS THE BETTER THREAT FOR CONVECTION LATER THIS MORNING WILL BE ACROSS NORTHERN MICHIGAN AS THE WARM FRONT LIFTS NORTH. HOWEVER SIGNIFICANT CONVECTIVE DEVELOPMENT IS NOTED EARLY THIS MORNING ACROSS CENTRAL MN. I AM CONCERNED ABOUT MCS PROPOGATION THICKNESS TOOLS WHICH SUGGEST THAT THIS WILL DIVE SE OR EVEN SSE EVENTUALLY ACROSS WI LATER THIS MORNING. IF THIS ACTIVITY HOLDS TOGETHER WE COULD ALREADY BE DEALING WITH A ROUND OF STRONG TO SEVERE STORMS HERE BY EARLY TO MID AFTERNOON PARTICULARLY OVER OUR NORTHERN COUNTIES. UPSTREAM RGNL RADAR TRENDS WILL NEED TO BE MONITORED VERY CLOSELY THROUGH THE MORNING. IT IS NOTED THAT THE SPC SREF DERECHO COMPOSITE PARAMETER REACHES VALUES OF 2-3 ACROSS WI THIS MORNING AND THEN OVER LWR MI BY THIS AFTN. EXTRAPOLATION OF LATEST HRRR GUIDANCE ALSO SHOWS THE THREAT FOR CONVECTION OVER OUR NORTHERN COUNTIES TOWARD MID AFTN. STILL LOOKING FOR LINGERING SHOWERS/TSTORMS THURSDAY. CANNOT RULE OUT SOME STRONG TO SEVERE STORMS ESPECIALLY OVER OUR SE FCST AREA THRU MIDDAY UNTIL THE COLD FRONT CLEARS THAT AREA. SOME STORMS MAY STILL LINGER EVEN THROUGH THE AFTERNOON AIDED BY A COUPLE OF FAIRLY STRONG SHORTWAVES TRACKING EAST ACROSS THE AREA. HOWEVER THE SVR WX THREAT BY THURSDAY AFTERNOON SHOULD BE FURTHER SOUTH ACROSS IN/OH. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 345 AM EDT WED JUL 25 2012 THE UPPER LOW OVER SASKATCHEWAN IS PROGGED TO DROP SOUTHEAST ACROSS THE GREAT LAKES REGION THURSDAY NIGHT AND FRIDAY. AS THIS FEATURE AND ASSOCIATED COLDER TEMPS ALOFT COME OVERHEAD ON FRIDAY AND COMBINE WITH SFC HEATING/INSTABILITY ... COVERAGE OF SHOWER/TSTMS SHOULD INCREASE BY AFTERNOON. A WEAK SFC TROUGH DROPPING SOUTH THROUGH LWR MI ON FRIDAY IS EXPECTED TO ENHANCE SFC CONVERGENCE. SHOWERS WILL END FRIDAY EVENING AS THE WAVE MOVES OUT AND DRIER ARRIVES FROM THE NORTH. MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AN AREA OF SFC HIGH PRESSURE DRIFTING SLOWLY EAST ACROSS THE GREAT LAKES OVER THE COMING WEEKEND. A PLEASANT/COMFORTABLE AIR MASS IS EXPECTED TO ACCOMPANY THIS FEATURE WITH DEW POINTS AROUND 60. HIGHS SHOULD BE IN THE LOWER TO MID 80S WITH LOWS AROUND 60. SHOWER/TSTM CHANCES WILL BE REINTRODUCED EARLY NEXT WEEK AS THE AIR MASS GRADUALLY BECOMES A BIT WARMER AND INCREASINGLY HUMID ON THE BACK SIDE OF THE SFC HIGH. HOWEVER RIGHT NOW THE CHANCES FOR RAIN DO NOT LOOK PARTICULARLY GOOD... WITH ONLY ISOLATED TO WIDELY SCATTERED COVERAGE EXPECTED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1203 AM EDT WED JUL 25 2012 VFR THROUGH WEDNESDAY WITH SOME SCATTERED THUNDERSTORMS POSSIBLE BY LATE WEDNESDAY AFTERNOON. SOUTHWEST WINDS WILL PICK UP WEDNESDAY MORNING WITH SOME GUSTS OVER 20 KNOTS POSSIBLE WEDNESDAY AFTERNOON. && .MARINE... ISSUED AT 345 AM EDT WED JUL 25 2012 00Z GLERL WAVE MODEL GUIDANCE SUGGESTS WAVE HEIGHTS SHOULD STAY BELOW SCA CRITERIA TODAY BUT SOUTHERLY WINDS WILL RAMP UP TO 10 TO 20 KTS LATER TODAY WHICH WILL KICK WAVE HEIGHTS UP TO AT LEAST 2 TO 3 FEET WITH HIGHEST WAVES UP TOWARD BIG AND LITTLE SABLE POINTS. THUNDERSTORMS WILL POSE A HAZARD TO MARINERS THROUGH AT LEAST MIDDAY THURSDAY. && .HYDROLOGY... ISSUED AT 345 AM EDT WED JUL 25 2012 RIVER LEVELS REMAIN LOW AND RAINFALL IS NOT EXPECTED TO BE HEAVY ENOUGH TO CAUSE SIGNIFICANT RIVER FLOODING ISSUES. HOWEVER THUNDERSTORMS MAY CAUSE URBAN AND SMALL STREAM TYPE FLOODING ISSUES TONIGHT WITH HIGH PRECIPITABLE WATER VALUES IN PLACE IN ADVANCE OF THE APPROACHING COLD FRONT TONIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MEADE AVIATION...OSTUNO HYDROLOGY...LAURENS MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
158 AM EDT WED JUL 25 2012 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES WILL CROSS THE MID ATLANTIC REGION THROUGH WEDNESDAY...PRODUCING WIDESPREAD THUNDERSTORMS THIS AFTERNOON AND EVENING...AND SCATTERED STORMS WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 PM TUESDAY... THE MCS FROM EARLIER THIS EVENING IS OFFSHORE AND SOUTH OF THE CWA...WITH STRONG SUBSIDENCE AND LOW LEVEL STABILIZATION IN ITS WAKE EVIDENT IN THE 00Z KGSO/KMHX RAOBS. STABILIZATION HAS BEEN FURTHER AIDED BY A BRIEF PERIOD OF STRONGER WESTERLY FLOW BETWEEN A MESO-HIGH OVER NORTHEAST TN AND THE PIEDMONT TROUGH...WHICH APPEARS TO HAVE HELPED DROP DEWPOINTS INTO THE MID 60S OVER THE WESTERN PIEDMONT. THERE IS STILL SOME ELEVATED INSTABILITY ABOVE THE SUBSIDENCE INVERSION WITH MUCAPE LIKELY STILL AT OR ABOVE 1000 J/KG...BUT PARCELS WOULD HAVE TO LIFT FROM NEAR 800 MILLIBARS TO TAP THIS ENERGY. THE 850-700MB FLOW OBSERVED AT KGSO WAS IN EXCESS OF 50 KNOTS...WHICH IS HIGHER THAN ANY OTHER NEARBY SITE BUT SEEMS REASONABLE GIVEN THE INTENSITY OF THE DEPARTING MCS. NONE OF THE MODELS WERE FORECASTING SUCH A STRONG LOW LEVEL JET...BUT THE FLOW IS GENERALLY DIVERGENT AND SHOULD NOT CONTRIBUTE TO LIFT ON ITS OWN. THERE IS ANOTHER REMNANT MCV TRACKING SOUTHEAST ACROSS SOUTHERN OHIO...WHICH THE RAP BRINGS INTO THE NORTHWEST AROUND 09Z. WE ARE NOT COMPLETELY COMFORTABLE REMOVING POPS FROM THE FORECAST GIVEN THE AFOREMENTIONED FORCING/ELEVATED INSTABILITY AND POOR MODEL PERFORMANCE...SO WE WILL LEAVE A SLIGHT CHANCE OF A THUNDERSTORM OVER THE WESTERN CWA. CLEARING IS FINALLY OCCURRING BEHIND THE MCS...BUT THIN DEBRIS CLOUDINESS WILL DRIFT OVERHEAD AT TIMES OVERNIGHT...AND GIVEN THAT DEWPOINTS HAVE FALLEN OVER THE WESTERN PIEDMONT...WE WILL TRIM 2 TO 3 DEGREES OFF FORECAST LOWS EVERYWHERE EXCEPT THE SOUTHEAST AREAS. WEDNESDAY... NORTHWEST FLOW WITH WEAK EMBEDDED SHORT WAVES EXPECTED TO CONTINUE TOMORROW...BUT THIS FLOW WILL WEAKEN WITH A CUTOFF TROUGH MOVING EAST OFF THE NEW ENGLAND COAST. IN TERMS OF THE AIR MASS AND THERMODYNAMIC PROFILE...LITTLE CHANGE IS EXPECTED...ALTHOUGH THE DAY WILL START OFF WITH MORE CLOUDINESS THAN TODAY. EXPECT ADDITIONAL SCATTERED AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS... BUT WITH WEAKER MID AND UPPER FLOW AND SHEAR...EXPECT COVERAGE TO BE REDUCED COMPARED TO TODAY. SEVERE STORM IMPACTS WILL ONCE AGAIN FAVOR DAMAGING WINDS GUSTS MORE THAN HAIL. WEDNESDAY CONVECTION EXPECTED TO END BY LATE EVENING FOLLOWED BY PARTLY CLOUDY OVERNIGHT PERIOD. HIGHS WEDNESDAY 89 NORTHWEST TO NEAR 95 SOUTHWEST...AND LOWS WEDNESDAY NIGHT 71 NORTHEAST TO NEAR 75 EXTREME SOUTH. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 1225 PM TUESDAY... MIGRATORY LOW LEVEL RIDGING MOVING EAST ACROSS THE AREA WILL PRODUCE SOUTHWEST TO WESTERLY FLOW AND INDUCE A HEAT RIDGE REFLECTED IN LOW LEVEL THICKNESSES IN EXCESS OF 1440 METERS AND 850 MILLIBAR TEMPERATURES OF 22 TO 24C. CORRESPONDING SURFACE HIGHS EXPECTED TO REACH UPPER 90S... POTENTIALLY SOME VERY LOW TRIPLE DIGITS. THESE ARE BELOW RECORDS FOR THE DATES...WITH THE EXCEPTION OF THU AT RDU. SEE CLIMATE SECTION BELOW. HIGH INSTABILITY WITH NO FORCING MECHANISM WILL FAVOR CLIMATOLOGICAL DIURNAL CONVECTION IN THE WESTERN PIEDMONT AND IN THE COASTAL PLAIN DUE TO DIFFERENTIAL HEATING AND SEA BREEZE PENETRATION...RESPECTIVELY. TROUGH APPROACHING FROM THE WEST AND AN ASSOCIATED SURFACE FRONT WILL APPROACH FROM THE NORTHWEST FRIDAY. FRONTAL PASSAGE WILL BE AFTER MAXIMUM HEATING FRIDAY...WITH HIGHS REACHING UPPER 90S...AGAIN WITH POTENTIALLY A STRAY 100 DEGREE READING. WILL INCREASE THE CHANCE OF SHOWERS LATER FRIDAY NIGHT DUE TO A LITTLE QUICKER FRONTAL PASSAGE AS DEPICTED ON LATEST MODEL RUNS. MILD AND MUGGY WITH LOWS WITHIN A DEGREE OR TWO OF MIDDLE 70S BOTH NIGHTS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 1225 PM TUESDAY... MEDIUM RANGE NWP GUIDANCE IS IN GOOD AGREEMENT REGARDING THE GRADUAL ESTABLISHMENT OF A MEAN TROUGH ALOFT OVER THE EAST COAST THIS WEEKEND THROUGH EARLY NEXT WEEK. AS THIS TROF BECOMES ESTABLISHED...THE SURFACE COLD FRONT EARLY THIS WEEKEND WILL PUSH THROUGH CENTRAL NORTH CAROLINA ON SATURDAY...WITH RELATIVELY COOLER AND DRIER (AND MORE STABLE) HIGH PRESSURE BUILDING ACROSS THE APPALACHIANS SUNDAY THROUGH TUESDAY. WITH THE DRIER NORTHWEST FLOW REGIME IN PLACE...ONLY SLIGHT CHANCE POPS EXPECTED SUNDAY AND MONDAY...WHILE A POTENTIAL SHORT WAVE DIGGING INTO THE EAST COAST TROUGH WILL INCREASE CHANCES ON TUESDAY. HIGH TEMPERATURES WILL BE NEAR NORMAL...IN THE 90 TO 95 DEGREE RANGE SATURDAY THROUGH MONDAY...POTENTIALLY A LITTLE COOLER TUESDAY IF WE GET A REINFORCING SHORT WAVE DEEPENING THE MEAN TROUGH. PERSISTENCE LOWS EXPECTED THROUGH THE PERIOD...BASICALLY 70 TO 74. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 155 AM... THUNDERSTORMS CROSSING THE VIRGINIA MOUNTAINS AT THIS TIME APPROACHING MUCH MORE STABLE NEAR SURFACE AIR OVER NORTH CAROLINA. HOWEVER INSTABILITY ALOFT MAY ALLOW THESE STORMS TO PERSIST INTO THE TRIAD... ARRIVING BEFORE 4 AM. OTHERWISE A LIGHT BREEZE TONIGHT WITH LOCALIZED MVFR FOG. OTHER THAN THE ABOVE MENTIONED THUNDERSTORM RISK THIS MORNING... CONVECTION SHOULD BE LESS WIDESPREAD AND LESS INTENSE THAN EXPERIENCED TUESDAY. BEST... THOUGH LIMITED... AFTERNOON COVERAGE IS FORECAST SOUTH OF GREENSBORO... WITH SLIGHT CHANCES OR LESS ELSEWHERE. EXPECT A DAILY THREAT FOR ISOLATED TO SCATTERED CONVECTION IN THE AFTERNOON AND EVENING HOURS INTO SUNDAY WITH ASSOCIATED SUB VFR CEILINGS AND VISIBILITY. SUB VFR FOG AND/OR LOW STRATUS POSSIBLE EACH MORNING.... ESPECIALLY FOR LOCATIONS THAT RECEIVE SUBSTANTIAL RAIN FROM THE PREVIOUS DAY/EVENING. OTHERWISE.... EXPECT VFR CONDITIONS WILL CONTINUE. && .CLIMATE... THE FOLLOWING ARE THE RECORD HIGH TEMPERATURES FOR THE 26TH AND 27TH: RDU GSO FAY THU (26TH): 101 IN 2005 102 IN 1914 104 IN 1940 FRI (27TH): 104 IN 1940 104 IN 1914 106 IN 1940 && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ NEAR TERM...SMITH/NMP SHORT TERM...MLM LONG TERM...MLM
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
403 AM CDT WED JUL 25 2012 .SHORT TERM... 00Z UPPER-AIR ANALYSIS AND WV SATELLITE SHOWS CONSIDERABLE MOISTURE IN PLACE ACROSS THE REGION. KAMA AND KMAF RESPECTIVELY HAVE 1.14 AND 1.11 INCH PRECIPITABLE WATER VALUES WHICH IS SOMEWHAT HIGH FOR THIS TIME OF YEAR. ALSO ARE SEEING SOME SHOWERS EARLY THIS MORNING ON THE RADAR ASSOCIATED WITH AN AREA OF MID-LEVEL CLOUD COVER. UPPER-AIR ANALYSIS SHOWS A TROF AXIS LOCATED ACROSS EASTERN NEW MEXICO THIS MORNING WITH THE MODELS SLOWLY SHIFTING THIS TOWARDS THE STATE LINE THROUGH THE DAY. MONSOON MOISTURE PLUME SHOULD MOVE BACK OVER THE WESTERN HALF OF THE FORECAST AREA THIS AFTERNOON AND DAYTIME HEATING SHOULD HELP TO DESTABILIZE THE ATMOSPHERE RESULTING IN A BIT MORE WIDESPREAD STORM ACTIVITY COMPARED TO YESTERDAY. ALL OF THIS IS ACCORDING TO THE VARIOUS RESOLUTIONS OF THE NAM MODEL AND TO LESSER EXTENT THE TTU WRF. THE GFS AND LATEST HRRR ARE NOT AS OPTIMISTIC AT ALL. WILL KEEP CHANCE OF THUNDERSTORMS OVER THE CENTRAL SOUTH PLAINS WHERE THE INSTABILITY AXIS MAY TRY TO SET UP THIS AFTERNOON AND THEN SHIFT THIS AREA WEST FOR EARLY TONIGHT. THERE COULD BE A FEW SHOWERS THAT LINGER ACROSS THE AREA INTO THURSDAY MORNING AS MONSOON MOISTURE AND TROF AXIS REMAIN NEAR THE REGION. HIGH TEMPERATURES CAME IN A BIT WARMER ON THE MOS GUIDANCE AND WILL KEEP THINGS A FEW DEGREES UNDER THIS DUE TO THE EXPECTED CLOUD COVER AND SHOWERS. JORDAN && .LONG TERM... THE EXTENDED FORECAST WILL BE PUNCTUATED BY MORE SUMMER HEAT...THOUGH THUNDERSTORMS MAY ALSO GIVE SOME LOCATIONS BRIEF RELIEF THURSDAY AND/OR FRIDAY. A SHORTWAVE TROUGH WILL GLIDE ACROSS THE MIDWEST ON THURSDAY...JUST GRAZING THE SOUTHERN PLAINS WITH WEAK 500-300 MB LAYER Q-VECTOR CONVERGENCE AND DRAWING THE MONSOONAL MOISTURE PLUME ACROSS WEST TEXAS. AT THE SAME TIME...THE TAIL END OF A COLD FRONT WILL EDGE TOWARD OR INTO THE AREA. THE 00Z GFS AND NAM DO HAVE THE THE WIND SHIFT ROUGHLY BISECTING THE FA FROM SW TO NE MIDDAY THURSDAY BEFORE STALLING OUT...WHILE THE ECMWF IS SOMEWHAT FURTHER NORTH...INTO THE TEXAS PANHANDLE. GIVEN THAT THE POSITION OF THE FRONTAL ZONE IS SOMEWHAT IN QUESTION...DETAILS IN CONVECTIVE INITIATION ALSO REMAIN SOMEWHAT UNCERTAIN...BUT WITH WEAK UPPER SUPPORT AND A RELATIVELY MOIST ATMOSPHERE IN PLACE /PWATS AT 130 TO OVER 150 PERCENT OF AVERAGE/...EXPECT DAYTIME HEATING TO LEAD TO SCATTERED AFTERNOON AND EVENING CONVECTION. PROGGED SFC MOISTURE AND RESULTANT INSTABILITY WILL BE A LITTLE HIGHER THAN WE HAVE SEEN RECENTLY THOUGH DEEP-LAYER SHEAR WILL STILL BE RATHER MEAGER. HENCE...DO NOT ANTICIPATE MUCH STORM ORGANIZATION...BUT COULD SEE A FEW STRONGER CORES THAT COULD PRODUCE SMALL HAIL...STOUT DOWNBURST WINDS AND LOCALLY HEAVY RAINS. ANY WEAK UPPER SUPPORT THURSDAY WILL QUICKLY WANE FRIDAY AS AN UPPER LEVEL RIDGE STRENGTHENS AND EXTENDS EASTWARD FROM THE SOUTHERN ROCKIES INTO THE SOUTHERN PLAINS. STILL...RESIDUAL LOW-LEVEL MOISTURE...A THINNING MID-LEVEL MOISTURE PLUME...STRONG HEATING AND PERHAPS A SFC BOUNDARY IN THE AREA MAY BE ENOUGH TO GENERATE ISOLATED TO WIDELY SCATTERED CONVECTION FRIDAY AFTERNOON AND EVENING. BEYOND THAT...THOUGH...THE UPPER RIDGE WILL BECOME CENTERED ACROSS THE SOUTHERN PLAINS AND IT SHOULD PUT THE KIBOSH ON STORM CHANCES THIS WEEKEND AND INTO AT LEAST THE FIRST PART OF NEXT WEEK AS IT PROMOTES SUBSIDENCE AND SHIFTS THE MONSOON MOISTURE BACK TO THE WEST. THE UPPER RIDGE AXIS MAY ATTEMPT TO SHIFT BACK WEST OF THE AREA BY DAY 7 OR DAY 8 IF THE GFS IS CORRECT...BUT THE ECMWF KEEPS THE CENTER OF THE HIGH NEARBY THROUGH THE REMAINDER OF NEXT WEAK. THUS...EXPECT HOT TEMPERATURES TO CONTINUE...AND HAVE FAVORED HIGHS SLIGHTLY ABOVE GUIDANCE FROM THIS WEEKEND ONWARD...GIVEN RECENT GUIDANCE BIASES WITH THE PREVIOUS UPPER RIDGE ACROSS THE SOUTH PLAINS THIS PAST WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 95 67 94 66 92 / 20 30 30 30 20 TULIA 94 68 96 67 92 / 20 30 30 30 20 PLAINVIEW 94 69 94 69 92 / 30 20 30 30 20 LEVELLAND 95 69 95 69 93 / 30 20 30 30 20 LUBBOCK 96 71 96 71 95 / 30 20 30 30 20 DENVER CITY 96 70 96 69 94 / 20 20 30 30 20 BROWNFIELD 95 71 96 69 94 / 30 20 30 30 20 CHILDRESS 100 75 100 74 99 / 20 20 30 30 20 SPUR 97 72 98 72 100 / 30 20 30 30 20 ASPERMONT 99 76 102 76 101 / 30 20 30 30 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 14/23
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1129 PM CDT TUE JUL 24 2012 .AVIATION... ISOLATED THUNDERSTORMS NOT EXPECTED TO HAVE A DIRECT IMPACT ON TERMINALS OVERNIGHT. SOUTHERLY SURFACE WINDS WILL VEER GRADUALLY OVERNIGHT...BECOMING SOUTH OR SOUTH SOUTHWEST BY 14Z WEDNESDAY. SURFACE WINDS EXPECTED TO GUST ABOVE 20 KT DURING THE DAY ON WEDNESDAY...PRIOR TO ARRIVAL OF COLD FRONT. COLD FRONT IS FORECAST TO ARRIVE AT NORTHERN TERMINALS BETWEEN 01Z AND 03Z THURSDAY...WITH SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP ALONG AND AHEAD OF FRONT DURING THE AFTERNOON AND EVENING. WILL WAIT FOR SIGNAL OF TIMING AND LOCATION OF THUNDERSTORMS TO BECOME MORE PRONOUNCED BEFORE ADDING SAME TO FORECAST. VFR FORECAST CONTINUES NEXT 24 HOURS. COCKRELL && .PREV DISCUSSION... /ISSUED 955 PM CDT TUE JUL 24 2012/ UPDATE... ALTHOUGH THE 00Z RUNS OF THE NAM AND RUC FORECASTING DRIER CONDITIONS LATER TONIGHT...THE RUC INDICATING CONVECTION SPREADING FROM WEST TO EAST THROUGH AROUND 06Z TO 09Z WEDNESDAY. WITH MID AND UPPER TROUGH LOCATED OVER THE CENTRAL AND SOUTHERN ROCKIES INTO THE PANHANDLES AND PRECIP WATERS BETWEEN ONE AND ONE AND ONE QUARTER INCHES ALONG WITH PLENTY OF LOW LEVEL MOISTURE AND SHORTWAVE ENERGY ACROSS THE FORECAST AREA...SPREAD SLIGHT CHANCE POPS EASTWARD ACROSS ALL OF THE PANHANDLES THROUGH 12Z WEDNESDAY AND WENT WITH AREAL QUALIFIER WORDING. 00Z KAMA SOUNDING ALONG INDICATING LIFTED INDEX OF -3 AND CAPE NEAR 1000 JOULES. NAM FORECASTING ANOTHER LOW LEVEL SOUTHERLY JET OF 40 KNOTS SETTING UP BY 09Z WEDNESDAY...SIMILAR TO LAST NIGHT. CANNOT COMPLETELY RULE OUT CONVECTION DEVELOPING ANYWHERE IN THE FORECAST AREA OVERNIGHT TONIGHT. BUMPED UP WINDS TONIGHT SLIGHTLY AND INCREASED SKY COVER. ALSO...UPDATED FIRE WEATHER GRIDS WITH THE LATEST 00Z NAM DATA. CLEANED UP THE DISCUSSION IN THE FIRE WEATHER FORECAST PRODUCT TO REMOVE CONTRACTIONS AND CHANGE FROM WIND SPEEDS WORDING FROM KNOTS TO MPH. ALSO MENTIONED WIND SHIFT ASSOCIATED WITH COLD FRONTAL PASSAGE WEDNESDAY NIGHT AND THURSDAY. ALL PUBLIC AND FIRE WEATHER PRODUCTS HAVE BEEN UPDATED AND SENT. SCHNEIDER PREV DISCUSSION... /ISSUED 631 PM CDT TUE JUL 24 2012/ AVIATION... SLOW-MOVING ISOLATED THUNDERSTORMS SEEN ON 88D AT THIS TIME DO NOT APPEAR TO POSE THREAT TO TERMINALS THIS EVENING. WILL CONTINUE TO MONITOR. OTHERWISE...SOUTHERLY SURFACE WINDS SHOULD CEASE GUSTING THIS EVENING...AND THEN INCREASE AGAIN WEDNESDAY MORNING AS NOCTURNAL LOW- LEVEL JET MIXES DOWNWARD. COLD FRONT WILL ENTER NORTHWEST PART OF FORECAST AREA ON WEDNESDAY...BEING POISED NEAR KDHT AND KGUY DURING THE HEAT OF THE DAY. KDHT AND KGUY WILL HAVE GREATER CHANCE TO BE DIRECTLY IMPACTED BY SCATTERED THUNDERSTORMS FROM LATE AFTERNOON TO EARLY EVENING WEDNESDAY...AS SHORTWAVE TROF PROVIDES ADDITIONAL LIFT. VFR FORECAST CONTINUES NEXT 24 HOURS. COCKRELL PREV DISCUSSION... /ISSUED 323 PM CDT TUE JUL 24 2012/ DISCUSSION... REGIONAL COMPOSITE RADAR SHOWS DEVELOPMENT OF THE SECOND ROUND OF CONVECTION EXPECTED TO PERSIST INTO THE EVENING HOURS FOR THE SOUTHERN PORTION OF THE CWA. ALSO BREEZY SURFACE WINDS OF 15 TO 20 KTS WITH GUSTS UP TO 30 KTS HAVE DEVELOPED AS THE SURFACE GRADIENT ACROSS THE PANHANDLES TIGHTENS. REST OF TODAY AND TONIGHT...ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS EVENING AS AN UPPER LEVEL WAVE CONTINUES A SSE TO NNW TRACK AROUND THE BASE OF THE UPPER LEVEL RIDGE. WHILE THE SEVERE THREAT IS LOW WITH ANY CONVECTION THAT FORMS THIS EVENING...BRIEF WIND GUSTS UP TO 45 MPH COULD BE EXPERIENCED NEAR DECAYING CELLS. STORM ACTIVITY SHOULD END PRIOR TO MIDNIGHT AS THE WAVE MOVES NORTH OF THE PANHANDLES. WEDNESDAY THROUGH FRIDAY...THE STUBBORN UPPER LEVEL RIDGE BEGINS TO BREAK DOWN EARLY WEDNESDAY MORNING AS AN UPPER LOW MOVES THROUGH ALBERTA TOWARDS THE GREAT LAKES LOWERING THE HEIGHT FIELD ACROSS THE NORTHERN AND CENTRAL PLAINS. THE RESULTING WEAKNESS IN THE RIDGE WILL ALLOW A WEAK COLD FRONT TO DIVE INTO THE PANHANDLES WEDNESDAY AND EXIT THE CWA FRIDAY. BREEZY CONDITIONS CAN BE EXPECTED WEDNESDAY IN ADVANCE OF THE FRONT AS THE SURFACE GRADIENT TIGHTENS WITH SUSTAINED 15 TO 25 MPH SOUTHERLY WINDS AND OCCASIONAL GUSTS ABOVE 30 MPH. BY MIDDAY WEDNESDAY RAIN CHANCES WILL RAISE AS THE APPROACHING FRONT PROVIDES ADDITIONAL FORCING. THE SEVERE THREAT THROUGH FRIDAY WILL REMAIN LOW DUE TO LOW CAPE VALUES GENERALLY AROUND 1500 J/KG AND THE POOR DEFINITION OF THE FRONT. BRIEF DIURNAL BREAKS IN CONVECTIVE ACTIVITY CAN BE EXPECTED EARLY THURSDAY AND FRIDAY MORNING BEFORE REFORMING DURING THE DAY. THERE HAS BEEN SOME MODEL DISCONTINUITY CONCERNING THE SPEED AT WHICH THE FRONT WILL MOVE THROUGH THE AREA. THE NAM HAS BEEN THE MOST AGGRESSIVE AND PUSHES THE FRONT COMPLETELY THROUGH THE AREA BY LATE THURSDAY, WHILE THE GFS KEEPS THE FRONT IN THE CWA THROUGH LATE FRIDAY. THE ECMWF HAD BEEN TRENDING CLOSER TO THE NAM PREVIOUSLY BUT HAS BEGUN TO TREND CLOSER TO THE GFS WITH TIME. AS SUCH HAVE GONE WITH A BLEND OF THE GFS AND ECMWF OF THE SPEED OF THE FRONT AND KEPT RAIN CHANCES THROUGH FRIDAY. SATURDAY THROUGH WEDNESDAY...BY SATURDAY THE UPPER LEVEL RIDGE STRENGTHENS TO END RAIN CHANCES FOR THE REST OF THE WEEK AND THROUGH THE MIDDLE OF NEXT WEEK. TEMPERATURES...STUCK CLOSE TO THE GFS MAXIMUM TEMPERATURES THROUGH FRIDAY AND MINIMUM TEMPERATURES THROUGH THE FORECAST. LEANED CLOSER TO THE ECMWF HIGH TEMPERATURE TOWARDS THE END OF THE FORECAST AS THE GFS BEGAN TO TREND BACK TO CLIMO UNDER A STRENGTHENING RIDGE. 14 FIRE WEATHER... STRONG SOUTHERLY WINDS ARE EXPECTED TO DIMINISH DURING THE EVENING HOURS AS RELATIVE HUMIDITY VALUES BEGIN TO REBOUND. WILL SEE ANOTHER ROUND OF STRONG SOUTHERLY 20-FT WINDS OF 15 TO 20 KTS WEDNESDAY MAINLY IN THE NORTHEASTERN SECTIONS OF THE PANHANDLES. RELATIVE HUMIDITY VALUES AT THAT TIME ARE EXPECTED TO DROP TO BELOW 25 PERCENT BRIEFLY BEFORE REBOUNDING IN THE ADVANCE OF AN APPROACHING COLD FRONT. THE INCREASED MOISTURE WILL PROMOTE ISOLATED TO SCATTERED SHOWERS WEDNESDAY THROUGH FRIDAY. DRY AND HOT WEATHER IS EXPECTED TO RETURN BY THE WEEKEND. 14 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 03/11
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1042 AM CDT WED JUL 25 2012 .DISCUSSION... ISSUED 1041 AM CDT WED JUL 25 2012 THE WARM FRONT IS CONTINUING TO LIFT NORTHEAST ACROSS CENTRAL IL WITH DRIER AIR BEHIND IT. DEWPOINTS ARE HOLDING IN THE LOWER 70S ALONG AND NORTH OF THE FRONT. OUR HIGH TEMPS WILL BE CLOSELY TIED TO HOW MUCH DRY AIR MIXES TO THE SURFACE. IF OUR DEWPOINTS DO NOT MIX DOWN INTO THE 60 TO 65 DEGREE RANGE, OUR HIGH TEMPS WILL MOST LIKELY NOT REACH 103-106 RANGE IN THOSE AREAS. WE TRIMMED HIGHS SLIGHTLY DUE TO SOME DELAY IN MIXING SO FAR, AND THE AMOUNT OF MOISTURE/DEWPOINT LEVELS IN OUR 12Z SOUNDING. STILL...WE WILL REACH VERY CLOSE TO RECORD HIGHS SOUTHWEST OF THE FRONT. CLOUD COVER LOOKS TO BE MINIMAL FOR AT LEAST THE WESTERN HALF OF THE AREA. THE CU RULE IS SHOWING CU FORMATION MORE FAVORABLE EAST OF I-57. HOWEVER...EVEN THOSE CLOUDS WILL BE A THIN LAYER AND NOT LAST VERY LONG INTO THE AFTERNOON. NO OTHER CHANGES WERE NEEDED TO THE GOING FORECAST. UPDATED INFO WILL BE AVAILABLE SHORTLY. SHIMON/ECT && .AVIATION... ISSUED 633 AM CDT WED JUL 25 2012 VFR THROUGHOUT THE FORECAST FOR NOW. WARM FRONT LIFTING BACK THROUGH THE AREA THIS MORNING...WITH WINDS RETURNING TO SWRLY AND GUSTING 20-25 KTS THIS AFTERNOON AS THE APPROACHING STORM SYSTEM BRINGS A PRESSURE GRADIENT BACK TO THE REGION. SOME SCT AC POSSIBLE THIS AFTERNOON...SHORT TIME OF CLEARING AGAIN THIS EVENING. AS THE SYSTEM PASSES TO THE NORTH...ANOTHER FRONT DROPS BACK INTO THE AREA. POPS START TO SPREAD TONIGHT...MAINLY AFTER MIDNIGHT. BROUGHT VCSH FOR PIA AND BMI AT 09Z...BUT MOST OF PRECIP WILL AFFECT TOMORROW DURING THE LATE AFTERNOON. NOT GETTING MORE EXPANSIVE THAN THAT RIGHT NOW. HJS && .FIRE WEATHER... ISSUED 300 AM CDT WED JUL 25 2012 HAVE CONCERNS WITH RED FLAG POTENTIAL FOR THIS AFTERNOON. DEEP MIXING SHOULD ALLOW DEW POINTS TO FALL INTO THE LOWER 60S ACROSS A GOOD PORTION OF THE CWA THIS AFTERNOON. WITH THE BRUTAL TEMPERATURES EXPECTED...THIS LEVEL OF MIXING WOULD DROP HUMIDITY VALUES INTO THE 20-25 PERCENT RANGE THIS AFTERNOON. MAIN ISSUE IS THAT WINDS WILL BE A BIT BORDERLINE. SURFACE WIND GUSTS AROUND 25 MPH WILL BE POSSIBLE ACROSS PRIMARILY AREAS WEST OF I-55 BY THIS AFTERNOON...BUT 20-FOOT SUSTAINED WINDS WILL BE CLOSER TO 15 MPH... JUST SHY OF CRITERIA. WILL CONTINUE THE SPECIAL WEATHER STATEMENT TO HIGHLIGHT THE FIRE DANGER...AND CONTINUE TO MONITOR FOR ANY POTENTIAL NEED FOR A RED FLAG WARNING. GEELHART && .CLIMATE... ISSUED 300 AM CDT WED JUL 25 2012 RECORD HIGH TEMPERATURES FOR TODAY... BLOOMINGTON...... 106/1934 CHAMPAIGN........ 104/1934 CHARLESTON....... 105/1934 DECATUR.......... 104/1934 JACKSONVILLE..... 108/1934 LINCOLN.......... 105/1934 OLNEY............ 103/1940 PALESTINE........ 103/1901 PEORIA........... 104/1930 SPRINGFIELD...... 103/1936 GEELHART && .PREV DISCUSSION... ISSUED 300 AM CDT WED JUL 25 2012 LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY CURVING AROUND THE WEST AND SOUTHERN FRINGES OF THE FORECAST AREA EARLY THIS MORNING...PUSHING NORTHWARD. HAVE BEEN SEEING SOME SCATTERED THUNDERSTORMS DEVELOPING OVER MAINLY THE EASTERN HALF OF THE CWA THE LAST FEW HOURS...BUT A LARGE AREA OF CLEAR SKIES WAS JUST TO OUR WEST. TEMPERATURES NORTH OF I-74 HAVE DIPPED INTO THE LOWER 70S AS OF 2 AM...BUT STILL SEEING QUITE A FEW LOWER 80S CLOSER TO THE BOUNDARY. MAIN CONCERNS ARE IN THE SHORT TERM...NAMELY THE RECORD HEAT TODAY AND ANY POTENTIAL NEED FOR ADJUSTMENTS TO HEADLINES. ALSO HAVE CONCERNS WITH CONVECTIVE DEVELOPMENT OVER THE NEXT 24 TO 36 HOURS. SHORT TERM...TODAY THROUGH THURSDAY NIGHT... LATEST VERSIONS OF THE NAM-12 AND HRRR HAVE A FAIR HANDLE ON THE CURRENT CONVECTION...AND HAVE THE RAIN OUT OF THE AREA BY MID- MORNING. WILL MAKE A LAST-MINUTE CALL ON HOW TO HANDLE THE ACTIVITY IN THE ZONES. OTHERWISE...THE MAIN STORY WILL BE THE BRUTAL HEAT. TIME-HEIGHT HUMIDITY CROSS SECTIONS SHOWING ANY CLOUD COVER RAPIDLY MOVING EAST OF THE AREA LATE THIS MORNING AS THE FRONT LIFTS NORTH OF THE AREA. DEEP MIXING FROM AROUND 750 MB SHOULD BRING DRIER AIR DOWN FROM ABOVE..AND HELP DROP DEW POINTS INTO THE 60-65 DEGREE RANGE THIS AFTERNOON. WINDS ALSO EXPECTED TO PICK UP AND GUST TO AROUND 20-25 MPH. TEMPERATURES AGAIN EXPECTED TO SOAR INTO TRIPLE DIGIT TERRITORY...AND HAVE NOT MADE ANY CHANGES TO EARLIER HIGHS OF 103-107. MUCH OF THE CWA LIKELY TO SEE RECORD HIGHS TODAY. WITH THE DRIER AIR...HEAT INDEX VALUES SHOULD ONLY BE A FEW DEGREES ABOVE THE OBSERVED TEMPERATURES. THERE ARE SOME CONCERNS THAT THE HEAT ADVISORY WILL NEED TO BE EXTENDED IN AREAS SOUTH OF I-70 THROUGH THURSDAY. HOWEVER...THE NEED IS NOT CLEAR-CUT...DUE TO POTENTIAL FOR CLOUDS AND STORMS. UPPER RIDGE OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO FLATTEN TODAY...AS A COLD FRONT DROPS SOUTHEAST TOWARD THE AREA. PASSAGE OF THE FRONT THROUGH OUR CWA WILL LIKELY TAKE UNTIL MIDDAY OR EARLY AFTERNOON ON THURSDAY. WILL SEE SCATTERED THUNDERSTORMS WEST OF I-55 DEVELOP LATER TONIGHT AS THE FRONT APPROACHES...THEN INCREASE OVER THE CWA ON THURSDAY WITH THE HEATING AHEAD OF THE FRONT. MAIN SEVERE WEATHER THREAT TODAY WILL REMAIN TO THE NORTH...BUT SOME SEVERE STORMS ARE POSSIBLE LATE THURSDAY MORNING INTO THE AFTERNOON. WILL SEE SCATTERED STORMS LINGER INTO EVENING ACROSS THE EASTERN CWA. THE NAM MODEL DOES DEVELOP SOME ADDITIONAL SHOWERS LATE THURSDAY NIGHT WITH A SECONDARY BOUNDARY COMING THROUGH THE AREA...BUT THIS DOES NOT SEEM LIKELY AT THE MOMENT. LONG TERM...FRIDAY THROUGH TUESDAY... UPPER RIDGE TO RE-ESTABLISH ITSELF OVER THE ROCKIES THIS WEEKEND...WITH A BROAD TROUGH PUSHING THROUGH THE GREAT LAKES. THIS WILL ALLOW FOR SOME MORE REASONABLE TEMPERATURES FOR THE WEEKEND. AS THE RIDGE BEGINS TO SHIFT BACK EASTWARD AGAIN... POTENTIAL FOR MCS ACTIVITY OVER THE TOP OF THE RIDGE WILL INCREASE OVER OUR AREA. MOST LIKELY TIME FRAMES FOR THIS WILL BE FROM SUNDAY NIGHT THROUGH TUESDAY...BUT EXACT LOCATIONS STILL A BIT OF A QUESTION. AS SUCH...WILL NOT GO OVERBOARD ON THE RAIN CHANCES AT THIS TIME. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ036-040>042- 047>057-061>063-066>068-071>073. HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031-037-038- 043>046. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
638 AM CDT WED JUL 25 2012 .DISCUSSION... ISSUED 300 AM CDT WED JUL 25 2012 LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY CURVING AROUND THE WEST AND SOUTHERN FRINGES OF THE FORECAST AREA EARLY THIS MORNING...PUSHING NORTHWARD. HAVE BEEN SEEING SOME SCATTERED THUNDERSTORMS DEVELOPING OVER MAINLY THE EASTERN HALF OF THE CWA THE LAST FEW HOURS...BUT A LARGE AREA OF CLEAR SKIES WAS JUST TO OUR WEST. TEMPERATURES NORTH OF I-74 HAVE DIPPED INTO THE LOWER 70S AS OF 2 AM...BUT STILL SEEING QUITE A FEW LOWER 80S CLOSER TO THE BOUNDARY. MAIN CONCERNS ARE IN THE SHORT TERM...NAMELY THE RECORD HEAT TODAY AND ANY POTENTIAL NEED FOR ADJUSTMENTS TO HEADLINES. ALSO HAVE CONCERNS WITH CONVECTIVE DEVELOPMENT OVER THE NEXT 24 TO 36 HOURS. SHORT TERM...TODAY THROUGH THURSDAY NIGHT... LATEST VERSIONS OF THE NAM-12 AND HRRR HAVE A FAIR HANDLE ON THE CURRENT CONVECTION...AND HAVE THE RAIN OUT OF THE AREA BY MID- MORNING. WILL MAKE A LAST-MINUTE CALL ON HOW TO HANDLE THE ACTIVITY IN THE ZONES. OTHERWISE...THE MAIN STORY WILL BE THE BRUTAL HEAT. TIME-HEIGHT HUMIDITY CROSS SECTIONS SHOWING ANY CLOUD COVER RAPIDLY MOVING EAST OF THE AREA LATE THIS MORNING AS THE FRONT LIFTS NORTH OF THE AREA. DEEP MIXING FROM AROUND 750 MB SHOULD BRING DRIER AIR DOWN FROM ABOVE..AND HELP DROP DEW POINTS INTO THE 60-65 DEGREE RANGE THIS AFTERNOON. WINDS ALSO EXPECTED TO PICK UP AND GUST TO AROUND 20-25 MPH. TEMPERATURES AGAIN EXPECTED TO SOAR INTO TRIPLE DIGIT TERRITORY...AND HAVE NOT MADE ANY CHANGES TO EARLIER HIGHS OF 103-107. MUCH OF THE CWA LIKELY TO SEE RECORD HIGHS TODAY. WITH THE DRIER AIR...HEAT INDEX VALUES SHOULD ONLY BE A FEW DEGREES ABOVE THE OBSERVED TEMPERATURES. THERE ARE SOME CONCERNS THAT THE HEAT ADVISORY WILL NEED TO BE EXTENDED IN AREAS SOUTH OF I-70 THROUGH THURSDAY. HOWEVER...THE NEED IS NOT CLEAR-CUT...DUE TO POTENTIAL FOR CLOUDS AND STORMS. UPPER RIDGE OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO FLATTEN TODAY...AS A COLD FRONT DROPS SOUTHEAST TOWARD THE AREA. PASSAGE OF THE FRONT THROUGH OUR CWA WILL LIKELY TAKE UNTIL MIDDAY OR EARLY AFTERNOON ON THURSDAY. WILL SEE SCATTERED THUNDERSTORMS WEST OF I-55 DEVELOP LATER TONIGHT AS THE FRONT APPROACHES...THEN INCREASE OVER THE CWA ON THURSDAY WITH THE HEATING AHEAD OF THE FRONT. MAIN SEVERE WEATHER THREAT TODAY WILL REMAIN TO THE NORTH...BUT SOME SEVERE STORMS ARE POSSIBLE LATE THURSDAY MORNING INTO THE AFTERNOON. WILL SEE SCATTERED STORMS LINGER INTO EVENING ACROSS THE EASTERN CWA. THE NAM MODEL DOES DEVELOP SOME ADDITIONAL SHOWERS LATE THURSDAY NIGHT WITH A SECONDARY BOUNDARY COMING THROUGH THE AREA...BUT THIS DOES NOT SEEM LIKELY AT THE MOMENT. LONG TERM...FRIDAY THROUGH TUESDAY... UPPER RIDGE TO RE-ESTABLISH ITSELF OVER THE ROCKIES THIS WEEKEND...WITH A BROAD TROUGH PUSHING THROUGH THE GREAT LAKES. THIS WILL ALLOW FOR SOME MORE REASONABLE TEMPERATURES FOR THE WEEKEND. AS THE RIDGE BEGINS TO SHIFT BACK EASTWARD AGAIN... POTENTIAL FOR MCS ACTIVITY OVER THE TOP OF THE RIDGE WILL INCREASE OVER OUR AREA. MOST LIKELY TIME FRAMES FOR THIS WILL BE FROM SUNDAY NIGHT THROUGH TUESDAY...BUT EXACT LOCATIONS STILL A BIT OF A QUESTION. AS SUCH...WILL NOT GO OVERBOARD ON THE RAIN CHANCES AT THIS TIME. GEELHART && .AVIATION... ISSUED 633 AM CDT WED JUL 25 2012 VFR THROUGHOUT THE FORECAST FOR NOW. WARM FRONT LIFTING BACK THROUGH THE AREA THIS MORNING...WITH WINDS RETURNING TO SWRLY AND GUSTING 20-25 KTS THIS AFTERNOON AS THE APPROACHING STORM SYSTEM BRINGS A PRESSURE GRADIENT BACK TO THE REGION. SOME SCT AC POSSIBLE THIS AFTERNOON...SHORT TIME OF CLEARING AGAIN THIS EVENING. AS THE SYSTEM PASSES TO THE NORTH...ANOTHER FRONT DROPS BACK INTO THE AREA. POPS START TO SPREAD TONIGHT...MAINLY AFTER MIDNIGHT. BROUGHT VCSH FOR PIA AND BMI AT 09Z...BUT MOST OF PRECIP WILL AFFECT TOMORROW DURING THE LATE AFTERNOON. NOT GETTING MORE EXPANSIVE THAN THAT RIGHT NOW. HJS && .FIRE WEATHER... ISSUED 300 AM CDT WED JUL 25 2012 HAVE CONCERNS WITH RED FLAG POTENTIAL FOR THIS AFTERNOON. DEEP MIXING SHOULD ALLOW DEW POINTS TO FALL INTO THE LOWER 60S ACROSS A GOOD PORTION OF THE CWA THIS AFTERNOON. WITH THE BRUTAL TEMPERATURES EXPECTED...THIS LEVEL OF MIXING WOULD DROP HUMIDITY VALUES INTO THE 20-25 PERCENT RANGE THIS AFTERNOON. MAIN ISSUE IS THAT WINDS WILL BE A BIT BORDERLINE. SURFACE WIND GUSTS AROUND 25 MPH WILL BE POSSIBLE ACROSS PRIMARILY AREAS WEST OF I-55 BY THIS AFTERNOON...BUT 20-FOOT SUSTAINED WINDS WILL BE CLOSER TO 15 MPH... JUST SHY OF CRITERIA. WILL CONTINUE THE SPECIAL WEATHER STATEMENT TO HIGHLIGHT THE FIRE DANGER...AND CONTINUE TO MONITOR FOR ANY POTENTIAL NEED FOR A RED FLAG WARNING. GEELHART && .CLIMATE... ISSUED 300 AM CDT WED JUL 25 2012 RECORD HIGH TEMPERATURES FOR TODAY... BLOOMINGTON...... 106/1934 CHAMPAIGN........ 104/1934 CHARLESTON....... 105/1934 DECATUR.......... 104/1934 JACKSONVILLE..... 108/1934 LINCOLN.......... 105/1934 OLNEY............ 103/1940 PALESTINE........ 103/1901 PEORIA........... 104/1930 SPRINGFIELD...... 103/1936 GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ036-040>042- 047>057-061>063-066>068-071>073. HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR ILZ027>031-037-038-043>046. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
548 AM MDT WED JUL 25 2012 .UPDATE... ISSUED AT 457 AM MDT WED JUL 25 2012 ELEVATED THUNDERSTORMS HAVE DEVELOPED FARTHER TO THE EAST THAN PREVIOUSLY EXPECTED...BEING DRIVEN BY ELEVATED FRONTAL ZONE AROUND H8 AND POCKET OF WEAKLY CAPPED INSTABILITY IN BTWN H75 AND H65. WHILE PRECIP COVERAGE HAS BEEN SPOTTY...MCK MEASURED A QUICK 0.2 OF RAIN IN ABOUT 15 MINUTES AS STORM PASSED. RAP INDICATES AREA OF ELEVATED INSTABILITY SHIFTS TO THE NORTH AND DIMINISHES DURING THE MORNING HOURS...BUT THINK A STORM OR TWO MAY CONTINUE TO DEVELOP ALONG ELEVATED FRONT THIS MORNING AS SATELLITE INDICATING LINEAR BAND OF COOLING CLOUD TOPS DEVELOPING FROM GOODLAND TO NORTON. AM A LITTLE CONCERNED ABOUT ANOTHER POCKET OF ELEVATED INSTABILITY ASSOCIATED WITH WEAK SHORT WAVE TROUGH THAT HAS BEEN DRIFTING TO THE NORTH AND WOULD NOT BE OUT OF THE QUESTION TO SEE A CELL OR TWO ALONG SOUTHERN FRINGE OF CWA AS FRONT INTERACTS WITH THIS AREA. NOT REALLY SEEING ANY SIGNS OF THIS ON SATELLITE RIGHT NOW AND WOULD LIKE TO SEE SOME CONFIRMATION WITH MORNING SOUNDINGS BEFORE CHANGING FORECAST GREATLY. ASIDE FROM EARLY MORNING CONVECTION...REST OF FORECAST STILL ON TRACK && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 258 AM MDT WED JUL 25 2012 03Z WATER VAPOR IMAGERY INDICATED LARGE AREA OF SUBSIDENCE/DRYING THAT WAS OVER THE AREA THE PAST FEW DAYS HAD SHIFTED TO THE NORTHEAST...WITH SUBTLE SHORT WAVE TROUGH MOVING ACROSS SOUTHERN KANSAS WITH STRONG SHORT WAVE TROUGH MOVING ACROSS THE US/CANADIAN BORDER. 00Z RAOBS SHOWED LITTLE CHANGE IN THERMAL PROFILES ACROSS THE AREA WITH LARGEST CHANGES NOTED AT DDC WHERE TEMPS BELOW H7 HAS WARMED AROUND 2C AND TEMPS BTWN H7 AND H5 HAD COOLED AROUND 2C. PRIMARY FORECAST CONCERN WILL BE PRECIPITATION CHANCES TODAY AND TONIGHT...FOLLOWED BY TEMPS THROUGH THE START OF THE WEEKEND. TODAY...COLD FRONT IS CURRENTLY ADVANCING ACROSS THE CWA AND WILL CONTINUE TO ADVANCE TO THE SOUTH BEFORE STALLING ACROSS SOUTHERN PORTION OF THE CWA LATE THIS MORNING. ALREADY SEEING A FEW SHOWERS AND THUNDERSTORMS POP UP BEHIND THE FRONT...ALTHOUGH PRECIP AMOUNTS LOOK TOP BE VERY SPOTTY AS UPDRAFTS REMAIN WEAK AND SHORT LIVED. POCKET OF LOW CINH AND WEAK INSTABILITY LOCATED AROUND H7 AND AREA OF FRONTOGENESIS LINE UP WITH CURRENT ACTIVITY PRETTY WELL AND GENERAL TRENDS WITH THESE FIELDS SUGGEST ACTIVITY SHOULD REMAIN CONFINED TO THE NORTHWESTERN CWA DURING THE MORNING HOURS. LARGE SCALE FORCING FOR ASCENT BEGINS TO INCREASE AS SHORT WAVE TROUGH APPROACHES NEB PANHANDLE AND DRIFTS TO THE SOUTHEAST. INITIALLY THOUGHT THAT PRECIPITATION WOULD STRUGGLE TO DEVELOP CLOSER TO STRONGER UPPER LEVEL FORCING AND INSTEAD FAVOR FRONTAL ZONE TO THE SOUTH BUT SEEING AS LIMITED INSTABILITY ALREADY BEING REALIZED...THINK COVERAGE WILL IMPROVES AS FORCING INCREASES...BEFORE SFC FRONT BECOMES PRIMARY FOCUS FOR STORMS LATE IN THE AFTERNOON. TONIGHT...BIG QUESTION FOR THE OVERNIGHT PERIOD WILL BE HOW LONG PRECIPITATION LINGERS ACROSS THE AREA. WHILE PERIOD OF LARGE SCALE FORCING FOR ASCENT AND MID LEVEL FRONTOGENESIS ARE IN PLACE ACROSS MUCH OF THE AREA AT 00Z...THESE FIELDS DIMINISH CONSIDERABLY DURING THE EVENING HOURS AND THINK BULK OF PRECIPITATION WILL BE TIED TO FRONTAL ZONE WHICH WILL BE MOVING QUICKLY OUT OF THE CWA. WHILE INITIAL THOUGHTS ARE MUCH OF THE CWA WILL BE DONE WITH PRECIPITATION AROUND 00Z...HAVE SOME CONCERNS THAT SOUNDINGS INDICATE SOME POTENTIAL DESTABILIZATION ACROSS EASTERN COLORADO AFTER FRONT PASSES. NOT SURE I CAN PUT REALLY GREAT CONFIDENCE INTO THIS SOLUTION...BUT WITH LATEST GEFS AS WELL AS LOCAL NEIGHBORHOOD PRECIPITATION GUIDANCE THINK LINGERING HIGHER POPS INTO AT LEAST 2Z IS WARRANTED. TOMORROW...NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ACROSS THE AREA AS H5 RIDGE AMPLIFIES OVER THE ROCKIES WITH SFC HIGH BRINGING FAIRLY LIGHT AND VARIABLE WINDS ACROSS THE CWA. WHILE THERE IS NOT IN THE WAY OF LARGE SCALE FORCING...GENERAL MODELS INDICATE SFC HEATING WILL BE ENOUGH TO REMOVE MUCH OF THE CINH ASSOCIATED WITH INSTABILITY AXIS THAT DEVELOPS ACROSS COLORADO. NOT REALLY CONFIDENT IN PRECIP CHANCES OR COVERAGE...BUT THINK CURRENT ISOLATED CHANCES IN THIS AREA LOOK REASONABLE ATTM. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 258 AM MDT WED JUL 25 2012 THURSDAY NIGHT-FRIDAY NIGHT...DESPITE SLOWLY AMPLIFYING RIDGE ACROSS THE AREA...THERE WILL BE PERIODS OF LARGE SCALE FORCING FOR ASCENT THROUGH THE PERIOD AS RIDGE AXIS REMAINS TO THE WEST OF THE AREA AND A FEW SMALL SHORT WAVE TROUGHS MOVE OVER THE TOP OF THE RIDGE AND IMPACT THE AREA. SOME DIFFERENCES EXIST WITH RESPECT TO HOW STRONG UPCOMING RIDGE WILL BE WHICH WILL STRONGLY IMPACT HOW MUCH INFLUENCE ANY OF THESE SMALL SCALE TROUGHS WILL HAVE. WHILE NAM AND SREF QUITE AGGRESSIVE DEVELOPING CONVECTION ACROSS NORTHERN CWA...GFS AND GEFS MUCH DRIER. FOR NOW...THINK GEFS SOLUTION OF 15-20 POPS REFLECTS THE EXPECTED PATTERN PRETTY WELL. THE NEXT UPPER LEVEL RIDGE WILL BUILD OVER THE INTERMOUNTAIN WEST AND OVER THE ROCKIES BY THIS WEEKEND. A FEW SHORTWAVE TROUGHS WILL MOVE THROUGH THE FLOW DURING THE PERIOD AND WITH SURFACE TROUGH DEEPENING ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED AFTERNOON THUNDERSTORMS MOST DAYS. BY EARLY NEXT WEEK...THE RIDGE WILL MOVE EASTWARD INTO THE PLAINS WITH THE MAIN CENTER OF THE HIGH POSITIONED ACROSS THE SOUTHERN PLAINS REGION MONDAY BEFORE RETROGRADING BACK INTO THE SOUTHERN ROCKY MOUNTAINS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 539 AM MDT WED JUL 25 2012 ISOLATED MORNING THUNDERSTORMS WILL CONTINUE THROUGH AT LEAST 15Z BEFORE MORE ORGANIZED THUNDERSTORMS DEVELOP AFTER 19Z IMPACTING BOTH TERMINALS BEFORE ENDING EARLY THIS EVENING. SFC RIDGE WILL BUILD OVER THE AREA OVERNIGHT WITH LIGHT AND VARIABLE WINDS BRINGING THE POTENTIAL FOR PATCHY MORNING FOG...ESPECIALLY AROUND MCK. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...JRM LONG TERM...JRM/PMM AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
508 AM MDT WED JUL 25 2012 .UPDATE... ISSUED AT 457 AM MDT WED JUL 25 2012 ELEVATED THUNDERSTORMS HAVE DEVELOPED FARTHER TO THE EAST THAN PREVIOUSLY EXPECTED...BEING DRIVEN BY ELEVATED FRONTAL ZONE AROUND H8 AND POCKET OF WEAKLY CAPPED INSTABILITY IN BTWN H75 AND H65. WHILE PRECIP COVERAGE HAS BEEN SPOTTY...MCK MEASURED A QUICK 0.2 OF RAIN IN ABOUT 15 MINUTES AS STORM PASSED. RAP INDICATES AREA OF ELEVATED INSTABILITY SHIFTS TO THE NORTH AND DIMINISHES DURING THE MORNING HOURS...BUT THINK A STORM OR TWO MAY CONTINUE TO DEVELOP ALONG ELEVATED FRONT THIS MORNING AS SATELLITE INDICATING LINEAR BAND OF COOLING CLOUD TOPS DEVELOPING FROM GOODLAND TO NORTON. AM A LITTLE CONCERNED ABOUT ANOTHER POCKET OF ELEVATED INSTABILITY ASSOCIATED WITH WEAK SHORT WAVE TROUGH THAT HAS BEEN DRIFTING TO THE NORTH AND WOULD NOT BE OUT OF THE QUESTION TO SEE A CELL OR TWO ALONG SOUTHERN FRINGE OF CWA AS FRONT INTERACTS WITH THIS AREA. NOT REALLY SEEING ANY SIGNS OF THIS ON SATELLITE RIGHT NOW AND WOULD LIKE TO SEE SOME CONFIRMATION WITH MORNING SOUNDINGS BEFORE CHANGING FORECAST GREATLY. ASIDE FROM EARLY MORNING CONVECTION...REST OF FORECAST STILL ON TRACK && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 258 AM MDT WED JUL 25 2012 03Z WATER VAPOR IMAGERY INDICATED LARGE AREA OF SUBSIDENCE/DRYING THAT WAS OVER THE AREA THE PAST FEW DAYS HAD SHIFTED TO THE NORTHEAST...WITH SUBTLE SHORT WAVE TROUGH MOVING ACROSS SOUTHERN KANSAS WITH STRONG SHORT WAVE TROUGH MOVING ACROSS THE US/CANADIAN BORDER. 00Z RAOBS SHOWED LITTLE CHANGE IN THERMAL PROFILES ACROSS THE AREA WITH LARGEST CHANGES NOTED AT DDC WHERE TEMPS BELOW H7 HAS WARMED AROUND 2C AND TEMPS BTWN H7 AND H5 HAD COOLED AROUND 2C. PRIMARY FORECAST CONCERN WILL BE PRECIPITATION CHANCES TODAY AND TONIGHT...FOLLOWED BY TEMPS THROUGH THE START OF THE WEEKEND. TODAY...COLD FRONT IS CURRENTLY ADVANCING ACROSS THE CWA AND WILL CONTINUE TO ADVANCE TO THE SOUTH BEFORE STALLING ACROSS SOUTHERN PORTION OF THE CWA LATE THIS MORNING. ALREADY SEEING A FEW SHOWERS AND THUNDERSTORMS POP UP BEHIND THE FRONT...ALTHOUGH PRECIP AMOUNTS LOOK TOP BE VERY SPOTTY AS UPDRAFTS REMAIN WEAK AND SHORT LIVED. POCKET OF LOW CINH AND WEAK INSTABILITY LOCATED AROUND H7 AND AREA OF FRONTOGENESIS LINE UP WITH CURRENT ACTIVITY PRETTY WELL AND GENERAL TRENDS WITH THESE FIELDS SUGGEST ACTIVITY SHOULD REMAIN CONFINED TO THE NORTHWESTERN CWA DURING THE MORNING HOURS. LARGE SCALE FORCING FOR ASCENT BEGINS TO INCREASE AS SHORT WAVE TROUGH APPROACHES NEB PANHANDLE AND DRIFTS TO THE SOUTHEAST. INITIALLY THOUGHT THAT PRECIPITATION WOULD STRUGGLE TO DEVELOP CLOSER TO STRONGER UPPER LEVEL FORCING AND INSTEAD FAVOR FRONTAL ZONE TO THE SOUTH BUT SEEING AS LIMITED INSTABILITY ALREADY BEING REALIZED...THINK COVERAGE WILL IMPROVES AS FORCING INCREASES...BEFORE SFC FRONT BECOMES PRIMARY FOCUS FOR STORMS LATE IN THE AFTERNOON. TONIGHT...BIG QUESTION FOR THE OVERNIGHT PERIOD WILL BE HOW LONG PRECIPITATION LINGERS ACROSS THE AREA. WHILE PERIOD OF LARGE SCALE FORCING FOR ASCENT AND MID LEVEL FRONTOGENESIS ARE IN PLACE ACROSS MUCH OF THE AREA AT 00Z...THESE FIELDS DIMINISH CONSIDERABLY DURING THE EVENING HOURS AND THINK BULK OF PRECIPITATION WILL BE TIED TO FRONTAL ZONE WHICH WILL BE MOVING QUICKLY OUT OF THE CWA. WHILE INITIAL THOUGHTS ARE MUCH OF THE CWA WILL BE DONE WITH PRECIPITATION AROUND 00Z...HAVE SOME CONCERNS THAT SOUNDINGS INDICATE SOME POTENTIAL DESTABILIZATION ACROSS EASTERN COLORADO AFTER FRONT PASSES. NOT SURE I CAN PUT REALLY GREAT CONFIDENCE INTO THIS SOLUTION...BUT WITH LATEST GEFS AS WELL AS LOCAL NEIGHBORHOOD PRECIPITATION GUIDANCE THINK LINGERING HIGHER POPS INTO AT LEAST 2Z IS WARRANTED. TOMORROW...NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ACROSS THE AREA AS H5 RIDGE AMPLIFIES OVER THE ROCKIES WITH SFC HIGH BRINGING FAIRLY LIGHT AND VARIABLE WINDS ACROSS THE CWA. WHILE THERE IS NOT IN THE WAY OF LARGE SCALE FORCING...GENERAL MODELS INDICATE SFC HEATING WILL BE ENOUGH TO REMOVE MUCH OF THE CINH ASSOCIATED WITH INSTABILITY AXIS THAT DEVELOPS ACROSS COLORADO. NOT REALLY CONFIDENT IN PRECIP CHANCES OR COVERAGE...BUT THINK CURRENT ISOLATED CHANCES IN THIS AREA LOOK REASONABLE ATTM. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 258 AM MDT WED JUL 25 2012 THURSDAY NIGHT-FRIDAY NIGHT...DESPITE SLOWLY AMPLIFYING RIDGE ACROSS THE AREA...THERE WILL BE PERIODS OF LARGE SCALE FORCING FOR ASCENT THROUGH THE PERIOD AS RIDGE AXIS REMAINS TO THE WEST OF THE AREA AND A FEW SMALL SHORT WAVE TROUGHS MOVE OVER THE TOP OF THE RIDGE AND IMPACT THE AREA. SOME DIFFERENCES EXIST WITH RESPECT TO HOW STRONG UPCOMING RIDGE WILL BE WHICH WILL STRONGLY IMPACT HOW MUCH INFLUENCE ANY OF THESE SMALL SCALE TROUGHS WILL HAVE. WHILE NAM AND SREF QUITE AGGRESSIVE DEVELOPING CONVECTION ACROSS NORTHERN CWA...GFS AND GEFS MUCH DRIER. FOR NOW...THINK GEFS SOLUTION OF 15-20 POPS REFLECTS THE EXPECTED PATTERN PRETTY WELL. THE NEXT UPPER LEVEL RIDGE WILL BUILD OVER THE INTERMOUNTAIN WEST AND OVER THE ROCKIES BY THIS WEEKEND. A FEW SHORTWAVE TROUGHS WILL MOVE THROUGH THE FLOW DURING THE PERIOD AND WITH SURFACE TROUGH DEEPENING ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED AFTERNOON THUNDERSTORMS MOST DAYS. BY EARLY NEXT WEEK...THE RIDGE WILL MOVE EASTWARD INTO THE PLAINS WITH THE MAIN CENTER OF THE HIGH POSITIONED ACROSS THE SOUTHERN PLAINS REGION MONDAY BEFORE RETROGRADING BACK INTO THE SOUTHERN ROCKY MOUNTAINS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1040 PM MDT TUE JUL 24 2012 VFR CONDITIONS ARE FORECAST FOR THE 6Z TAFS. LATEST RADAR SHOWS THE COLD FRONT MOVING INTO YUMA COUNTY. IF THE FRONT CONTINUES WITH ITS CURRENT SPEED IT WILL ARRIVE AT KGLD AND KMCK AROUND 17 OR 18Z. AHEAD OF THE FRONT WINDS WILL BE LIGHT. ONCE THE FRONT MOVES THROUGH WINDS WILL TURN TO THE NORTH AND BECOME GUSTY. DUE TO THE DRY AIR AHEAD OF THE FRONT AND LACK OF INSTABILITY BEHIND THE FRONT...MOST OF THE THUNDERSTORMS SHOULD BE TIED TO THE FRONT. SOME THUNDERSTORMS COULD BECOME SEVERE DURING THE AFTERNOON. THE STORMS WILL COME TO AN END DURING THE LATE AFTERNOON WITH THE WINDS DECLINING DURING THE EVENING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...JRM LONG TERM...JRM/PMM AVIATION...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
603 AM CDT WED JUL 25 2012 ...UPDATE TO AVIATION... .SYNOPSIS... ISSUED AT 418 AM CDT WED JUL 25 2012 AN INTENSE UPPER LOW OVER THE SOUTHERN CANADIAN PRAIRIES CONTINUED TO MOVE SLOWLY EAST DURING THE OVERNIGHT HOURS. THERE WERE TWO LOWS EVIDENT AT 850MB IN THE 25.00Z ANALYSIS. THE NORTHERN LOW WAS WELL INTO CANADA NEAR SASKATOON, SASKATCHEWAN. FARTHER SOUTH IN THE CONUS...A LOW WAS CENTERED EAST OF THE BLACK HILLS OF SOUTH DAKOTA. A FAIRLY INTENSE TEMPERATURE GRADIENT WAS NOTED ACROSS SOUTH DAKOTA WITH +20C AT BISMARCK, ND AND +31C NOSING INTO SOUTH CENTRAL SD PER THE RAP ANALYSIS. SEVERAL CLUSTERS OF THUNDERSTORMS DEVELOPED ACROSS SOUTH DAKOTA ALONG THIS BAROCLINIC ZONE, WITH A LARGE MCS ROLLING ACROSS NORTHERN MINNESOTA AS OF 08Z. ELSEWHERE...A SUBTLE BUT IMPORTANT SHORTWAVE TROUGH COULD BE PICKED OUT IN THE RAP ANALYSIS AND WATER VAPOR IMAGERY MOVING EAST THROUGH UTAH AND SOUTHWESTERN WYOMING...MOVING INTO WESTERN/NORTHWESTERN COLORADO. A SURFACE COLD FRONT AS OF 08Z EXTENDED FROM NORTH CENTRAL NEBRASKA TO NORTHEASTERN COLORADO. SURFACE WINDS BEHIND THE FRONT IN EASTERN COLORADO AND THE NEBRASKA PANHANDLE WERE NORTHWEST 20 TO 25 KNOTS WITH SOME GUSTS IN SOME PLACES EXCEEDING 30 KNOTS. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 418 AM CDT WED JUL 25 2012 THE MAIN CHALLENGE IN THE FORECAST PERTAINS TO THUNDERSTORM CHANCES, STRENGTH, AND LOCATION OF THOSE BEST CHANCES LATER ON THIS AFTERNOON AND TONIGHT AS THE COLD FRONT REACHES SOUTHWEST KANSAS. 850MB TEMPS AHEAD OF THE FRONT UP TO +31C SUGGEST ANOTHER DAY OF HIGHS IN THE 103 TO 106F RANGE WITH THE NORTHERN FORECAST AREA SEEING THE HOTTEST TEMPERATURES AGAIN...MUCH LIKE THE PAST FEW DAYS. IF THE STORMS HOLD OFF LONG ENOUGH...HAYS COULD REACH 108F AGAIN LIKE YESTERDAY. INITIAL THUNDERSTORMS SHOULD DEVELOP AS SURFACE TEMPERATURES APPROACH CONVECTIVE TEMPERATURE ALONG AN AXIS FROM ROUGHLY ELKHART TO SYRACUSE TO WAKEENEY-GOVE AREAS. OTHER STORMS MAY FORM FARTHER EAST TIED TO A WEAK MID LEVEL VORTICITY ANOMALY THAT WILL MOVE SLOWLY EAST ACROSS SOUTHWEST KANSAS DURING THE AFTERNOON. THESE STORMS SHOULD BE ALL THAT STRONG SINCE LOW LEVEL CONVERGENCE WILL BE ESSENTIALLY NON-EXISTENT (REMAINING FARTHER NORTH). THE MOST ORGANIZED THUNDERSTORMS WILL DEVELOP IN THE 22-00Z TIME FRAME FROM ROUGHLY LAKIN TO SCOTT CITY TO WAKEENEY. THESE STORMS WILL ADVANCE SLOWLY SOUTHEAST THROUGH THE EVENING HOURS WITH SUBSEQUENT DEVELOPMENT OF STORMS FORMING ON VARIOUS COLD POOL INTERACTIONS WHICH ARE IMPOSSIBLE TO PREDICT. IT IS UNCLEAR WHETHER A SMALL MCS MAY DEVELOP AND THRIVE PAST THE ~04Z TIME FRAME...AS LOW LEVEL MOISTURE, WHILE ADEQUATE IN THE UPPER 50S TO LOWER 60S...WILL NOT BE NEAR WHAT THE GFS MODEL IS SUGGESTING (A CHRONIC PROBLEM WITH THIS MODEL ALL SEASON). THE SHORTWAVE TROUGH MENTIONED IN THE SYNOPSIS SECTION ENTERING COLORADO WILL AID IN SOME INCREASED DEEP UPWARD VERTICAL MOTION LATE TONIGHT...BUT BY THE TIME THAT REACHES WESTERN KANSAS...MUCH OF THE CONVECTIVE ACTIVITY WILL LIKELY HAVE SHIFTED EAST INTO CENTRAL KANSAS. AS FAR AS THE POP FORECAST GOES...WILL BE INCREASING THE POPS TO 50-60 PERCENT NORTH OF A GARDEN CITY TO LARNED LINE TO INTERSTATE 70 CORRIDOR. AS FAR AS THE SEVERE WEATHER POTENTIAL GOES...THERE IS DEFINITELY A CHANCE AT AT LEAST SOME ISOLATED SEVERE WIND REPORTS GIVEN THE SIGNIFICANT TEMPERATURE-DEWPOINT SPREADS. STRONG UPDRAFTS ARE QUITE LIKELY GIVEN THE STRONG LOW LEVEL CONVERGENCE WITH THE SLOW MOVING FRONT. THIS WILL LEAD TO INTENSE DOWNDRAFTS AND EVEN A FEW SEVERE MICROBURSTS. THE HAIL THREAT IS RATHER LOW CONSIDERING THE POOR VERTICAL WIND SHEAR AND OVERALL WARM MID LEVEL TEMPERATURES AS WELL AS HIGH MELTING AND -20C LEVELS. WILL BE DECREASING POPS ACROSS MUCH OF THE FORECAST AREA DURING THE 06-12Z TIME FRAME WITH COLD ADVECTION TAKING OVER IN THE LOW LEVELS AS THE SYNOPTIC FRONT CONTINUES SOUTHEAST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 234 AM CDT WED JUL 25 2012 MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE DEVELOPING ACROSS THE FAR INTERMOUNTAIN WEST TODAY AND DRIFTING SLOWLY EAST ACROSS THE ROCKIES TO BEGIN THE PERIOD THURSDAY. IT WILL MOVE FURTHER INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND QUICKLY BRINGING A GENERALLY DRIER WEATHER PATTERN BACK TO WESTERN KANSAS DURING MUCH OF THE PERIOD. AIDING THIS DRIER PATTERN WILL BE A FAIRLY WEAK FLOW ALOFT ASSOCIATED WITH THE UPPER LEVEL RIDGING. TEMPERATURES ARE EXPECTED TO BE MORE SEASONAL THURSDAY IN WAKE OF A COLD FRONTAL PASSAGE LATE WEDNESDAY. A NORTH TO NORTHEAST LOW LEVEL FLOW WILL PREVAIL ACROSS WESTERN KANSAS THURSDAY HELPING TO LOWER H85 TEMPERATURES EVER SO SLIGHTLY WITH VALUES GENERALLY RANGING FROM THE MID 20S(C) ACROSS CENTRAL KANSAS TO THE UPPER 20S(C) IN EXTREME SOUTHWEST KANSAS. LOOK FOR HIGHS ONLY UP INTO THE 90S(F) THURSDAY AFTERNOON. A GRADUAL WARMING TREND IS STILL EXPECTED INTO THE WEEKEND AS THE AFOREMENTIONED UPPER LEVEL RIDGING APPROACHES FROM THE INTERMOUNTAIN WEST BY THURSDAY AND BEGINS TO PUSH EAST INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND. SHOULD SEE HIGHS CLIMBING UP NEAR TO JUST ABOVE 100F BY THE CLOSE OF THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 600 AM CDT WED JUL 25 2012 ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE ALONG AND AHEAD OF A COLD FRONT THAT WILL PUSH SLOWLY SOUTHEAST ACROSS SOUTHWEST KANSAS THIS AFTERNOON AND EVENING AND INTO SOUTH CENTRAL KANSAS TONIGHT. WILL INTRODUCE VCTS AND CB TO ALL TAF SITES THIS AFTERNOON AS A RESULT. ANY DEVELOPING STORMS WILL HAVE THE POTENTIAL OF BECOMING FAIRLY STRONG WITH GUSTY AND POSSIBLY DAMAGING OUTFLOW WINDS THE PRIMARY THREAT. OTHERWISE, VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TAF SITES THROUGH LATE THIS EVENING. AS FOR WINDS, A LEE SIDE TROUGH OF LOW PRESSURE IN EXTREME EASTERN COLORADO WILL BEGIN TO PUSH EAST INTO FAR WESTERN KANSAS THROUGH EARLY THIS AFTERNOON. AS A RESULT, SOUTHERLY WINDS OF 10 TO 15KT EARLY THIS MORNING WILL BECOME 15 TO 25KT ACROSS CENTRAL AND PORTIONS OF SOUTHWEST KANSAS BY EARLY AFTERNOON. A COLD FRONT IS THEN PROJECTED TO PUSH SLOWLY SOUTHEAST INTO WESTERN KANSAS MID TO LATE AFTERNOON MOVING ACROSS SOUTHWEST THIS EVENING...AND SOUTH CENTRAL KANSAS BY EARLY THURSDAY MORNING. WINDS ARE FORECAST TO BECOME NORTHERLY 10 TO 20KT BEHIND THE FRONT AS IT MOVES THROUGH THIS EVENING AND OVERNIGHT. && .PRELIMINARY POINT TEMPS/POPS... DDC 104 69 96 67 / 30 40 10 0 GCK 103 67 95 66 / 40 50 10 0 EHA 102 67 93 67 / 30 30 10 0 LBL 104 68 95 67 / 30 30 10 0 HYS 106 68 95 67 / 30 60 10 0 P28 103 74 98 71 / 10 40 20 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...JJOHNSON AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
754 AM EDT WED JUL 25 2012 .SYNOPSIS... ISSUED AT 345 AM EDT WED JUL 25 2012 A WARM FRONT WILL BRING POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY MAINLY NORTH OF INTERSTATE 96 THIS AFTERNOON. IT WILL BECOME HOT AND HUMID LATER TODAY SOUTH OF THE WARM FRONT. STRONG LOW PRESSURE TRACKING EAST ALONG THE WARM FRONT AND AN APPROACHING COLD FRONT WILL COMBINE TO BRING POTENTIAL FOR STRONG TO SEVERE STORMS TONIGHT THAT MAY PRODUCE DAMAGING WIND GUSTS AND HEAVY RAIN. TEMPERATURES WILL RETURN TO CLOSER TO NORMAL BEHIND THAT FRONT THURSDAY AND FRIDAY WITH A CONTINUED CHANCE OF SOME SHOWERS AND STORMS. FAIR WEATHER IS ANTICIPATED THIS WEEKEND. && .SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON) ISSUED AT 345 AM EDT WED JUL 25 2012 OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE TIMING/PROBABILITIES FOR CONVECTION THROUGH THE SHORT TERM FCST PERIOD AND TO ASSESS SEVERE WX POTENTIAL. THE SETUP LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS TONIGHT AS A STRONG LOW PRESSURE WAVE TRACKS EAST ALONG THE WARM FRONT AND COLD FRONT APPROACHES. THERE WILL BE PLENTY OF MOISTURE AND DECENT INSTABILITY ALONG WITH LIFT FROM THE APPROACHING FRONT. DEEP LAYER SHEAR VALUES RAMPING UP TO 35 TO 40 KTS ARE ALSO FAVORABLE FOR ORGANIZED SEVERE STORMS. 00Z 4KM WRF-NMM SIM Z GUIDANCE SHOWS CONVECTIVE DEVELOPMENT ACROSS OUR AREA FROM 00Z THRU 12Z TONIGHT. 00Z 4KM NSSL WRF GUIDANCE ALSO SHOWS POTENTIAL TONIGHT ESPECIALLY OVER OUR NORTHERN COUNTIES WHICH IS ALSO SUPPORTED BY THE 00Z ECMWF. AN ISOLATED TORNADO IS POSSIBLE EARLY TO MID EVENING WITH A SOMEWHAT VEERED WIND PROFILE WITH HEIGHT AND DEEP LAYER SHEAR VALUES CONDUCIVE TO SUPERCELLS. DAMAGING WIND GUSTS SHOULD BE THE MOST LIKELY SEVERE WX THREAT BUT HEAVY RAINFALL IS ALSO POSSIBLE. PRECIPITABLE WATER VALUES WILL REACH 1.75 TO 2.25 INCHES JUST AHEAD OF THE APPROACHING COLD FRONT ALONG WITH DECENT LOW TO MID LEVEL MOISTURE POOLING ALONG/AHEAD OF THE FRONT. THE GREATEST THREAT FOR SVR WX SHOULD COME FROM AROUND 23Z THIS EVE THROUGH 06Z THUR WITH GREATER INSTABILITY IN PLACE THROUGH THE EVENING HOURS AND WITH THE CRAVEN BROOKS SIG SVR PARAMETER UP AROUND 40-50K. THIS IS ALSO THE WINDOW OF TIME THAT THE SUPERCELL COMPOSITE PARAMETER IS FCST TO BE WAY UP AROUND A VALUE OF 12. THE SIG TOR PARAMETER REACHES VALUES OF 1 TO 4 FROM EARLY TO MID EVENING BEFORE DROPPING OFF OVERNIGHT. THE BEST CHC FOR AN ISOLATED TORNADO THIS EVE WOULD BE OVER OUR NORTHERN COUNTIES IN CLOSER PROXIMITY TO THE WARM FRONT WHERE 0-1KM AND 0-3KM SRH VALUES WILL BE ENHANCED. THE THREAT FOR SOME SEVERE STORMS WILL LINGER EVEN AFTER 06Z TONIGHT THROUGH AT LEAST DAYBREAK IF NOT MIDDAY THURSDAY... THE POTENTIAL JUST WILL NOT BE QUITE AS FAVORABLE AS BETWEEN 23Z-06Z TONIGHT AS SUGGESTED BY A CONSENSUS OF SPC SREF SVR WX PARAMETERS. THIS NOTION IS ALSO SUPPORTED BY OUR LOCAL SEVERE WX CLIMATOLOGY. THE FCST FOR THIS MORNING AND AFTERNOON IS TRICKY. MOST OF THE HIGHER RESOLUTION GUIDANCE SUGGESTS THE BETTER THREAT FOR CONVECTION LATER THIS MORNING WILL BE ACROSS NORTHERN MICHIGAN AS THE WARM FRONT LIFTS NORTH. HOWEVER SIGNIFICANT CONVECTIVE DEVELOPMENT IS NOTED EARLY THIS MORNING ACROSS CENTRAL MN. I AM CONCERNED ABOUT MCS PROPOGATION THICKNESS TOOLS WHICH SUGGEST THAT THIS WILL DIVE SE OR EVEN SSE EVENTUALLY ACROSS WI LATER THIS MORNING. IF THIS ACTIVITY HOLDS TOGETHER WE COULD ALREADY BE DEALING WITH A ROUND OF STRONG TO SEVERE STORMS HERE BY EARLY TO MID AFTERNOON PARTICULARLY OVER OUR NORTHERN COUNTIES. UPSTREAM RGNL RADAR TRENDS WILL NEED TO BE MONITORED VERY CLOSELY THROUGH THE MORNING. IT IS NOTED THAT THE SPC SREF DERECHO COMPOSITE PARAMETER REACHES VALUES OF 2-3 ACROSS WI THIS MORNING AND THEN OVER LWR MI BY THIS AFTN. EXTRAPOLATION OF LATEST HRRR GUIDANCE ALSO SHOWS THE THREAT FOR CONVECTION OVER OUR NORTHERN COUNTIES TOWARD MID AFTN. STILL LOOKING FOR LINGERING SHOWERS/TSTORMS THURSDAY. CANNOT RULE OUT SOME STRONG TO SEVERE STORMS ESPECIALLY OVER OUR SE FCST AREA THRU MIDDAY UNTIL THE COLD FRONT CLEARS THAT AREA. SOME STORMS MAY STILL LINGER EVEN THROUGH THE AFTERNOON AIDED BY A COUPLE OF FAIRLY STRONG SHORTWAVES TRACKING EAST ACROSS THE AREA. HOWEVER THE SVR WX THREAT BY THURSDAY AFTERNOON SHOULD BE FURTHER SOUTH ACROSS IN/OH. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 345 AM EDT WED JUL 25 2012 THE UPPER LOW OVER SASKATCHEWAN IS PROGGED TO DROP SOUTHEAST ACROSS THE GREAT LAKES REGION THURSDAY NIGHT AND FRIDAY. AS THIS FEATURE AND ASSOCIATED COLDER TEMPS ALOFT COME OVERHEAD ON FRIDAY AND COMBINE WITH SFC HEATING/INSTABILITY ... COVERAGE OF SHOWER/TSTMS SHOULD INCREASE BY AFTERNOON. A WEAK SFC TROUGH DROPPING SOUTH THROUGH LWR MI ON FRIDAY IS EXPECTED TO ENHANCE SFC CONVERGENCE. SHOWERS WILL END FRIDAY EVENING AS THE WAVE MOVES OUT AND DRIER ARRIVES FROM THE NORTH. MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AN AREA OF SFC HIGH PRESSURE DRIFTING SLOWLY EAST ACROSS THE GREAT LAKES OVER THE COMING WEEKEND. A PLEASANT/COMFORTABLE AIR MASS IS EXPECTED TO ACCOMPANY THIS FEATURE WITH DEW POINTS AROUND 60. HIGHS SHOULD BE IN THE LOWER TO MID 80S WITH LOWS AROUND 60. SHOWER/TSTM CHANCES WILL BE REINTRODUCED EARLY NEXT WEEK AS THE AIR MASS GRADUALLY BECOMES A BIT WARMER AND INCREASINGLY HUMID ON THE BACK SIDE OF THE SFC HIGH. HOWEVER RIGHT NOW THE CHANCES FOR RAIN DO NOT LOOK PARTICULARLY GOOD... WITH ONLY ISOLATED TO WIDELY SCATTERED COVERAGE EXPECTED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 754 AM EDT WED JUL 25 2012 THERE IS CONSIDERABLE UNCERTAINTY ON EXACTLY HOW THINGS ARE GOING TO PLAY OUT TODAY AND TONIGHT AS FAR AS TSTM ACTIVITY GOES. IN THE SHORT TERM... THE BAND OF TSTMS MOVING EAST FROM THE CHICAGO AND MKE AREAS EXTRAPOLATES EAST ACROSS SRN LWR MI BETWEEN ROUGHLY 14Z TO 18Z. THE CLOUD BASES... AS WELL AS THE VSBYS... WITH THESE TSTMS ARE MOSTLY IN THE VFR CATEGORY... BUT A TEMPO DIP INTO MVFR CATEGORY CANNOT BE RULED OUT ESPECIALLY AT GRR AND MKG. AFTER 18Z OR SO... WILL GO WITH THE IDEA THAT THE WARM SECTOR WILL SWEEP INTO THE REGION FROM THE SOUTHWEST AND THE ATMOSPHERE WILL BECOME TOO CAPPED /IE TOO WARM ALOFT/ FOR CONVECTION. SSW SFC WINDS SHOULD INCREASE AND BECOME GUSTY WITH THE ARRIVAL OF THE WARM SECTOR. WILL HOLD OFF ON REINTRODUCING TSTMS IN THE TAFS UNTIL AFTER 00Z AT MKG AND AFTER 03Z-04Z FARTHER SOUTH ALONG THE I-94 CORRIDOR. SOME GUIDANCE SUGGEST IT MAY EVEN BE LATER THAN THESE TIMES AS THE COLD FRONT ISNT REALLY DROPPING IN FROM THE NW UNTIL AFTER 06Z. && .MARINE... ISSUED AT 345 AM EDT WED JUL 25 2012 00Z GLERL WAVE MODEL GUIDANCE SUGGESTS WAVE HEIGHTS SHOULD STAY BELOW SCA CRITERIA TODAY BUT SOUTHERLY WINDS WILL RAMP UP TO 10 TO 20 KTS LATER TODAY WHICH WILL KICK WAVE HEIGHTS UP TO AT LEAST 2 TO 3 FEET WITH HIGHEST WAVES UP TOWARD BIG AND LITTLE SABLE POINTS. THUNDERSTORMS WILL POSE A HAZARD TO MARINERS THROUGH AT LEAST MIDDAY THURSDAY. && .HYDROLOGY... ISSUED AT 345 AM EDT WED JUL 25 2012 RIVER LEVELS REMAIN LOW AND RAINFALL IS NOT EXPECTED TO BE HEAVY ENOUGH TO CAUSE SIGNIFICANT RIVER FLOODING ISSUES. HOWEVER THUNDERSTORMS MAY CAUSE URBAN AND SMALL STREAM TYPE FLOODING ISSUES TONIGHT WITH HIGH PRECIPITABLE WATER VALUES IN PLACE IN ADVANCE OF THE APPROACHING COLD FRONT TONIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...LAURENS MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
748 AM EDT WED JUL 25 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED JUL 25 2012 ACTIVE WEATHER MORNING AS COMPLEX OF THUNDERSTORMS THAT HAS FORMED OVR NORTHERN MN IS POISED TO IMPACT MUCH OF CWA THROUGH AT LEAST EARLY AFTN. TSRA OVR WCNTRL INTO NORTHERN MN DEVELOPED IN AREA OF PVA FM SHORTWAVE LIFTING INTO NORTHERN MN AND WAS ALSO TIED TO H85-H7 MOISTURE ADVECTION/H7 FGEN AND RIGHT ENTRANCE JET FORCING/ISENTROPIC LIFT ON 300-305K SFC. COMPLEX IS WELL TO NORTH OF SFC WARM FRONT...MORE IN LINE WITH NORTHERN GRADIENT OF MLCAPE OVR 2000 J/KG AND WITHIN AREA OF SUFFICIENT DEEP LAYER SHEAR OVR 40 KTS. 0-1KM SHEAR TO 40 KTS HAS ALLOWED COLD POOLS TO DEVELOP AND BRIEFLY PROPAGATE EASTWARD. MOST WIND GUSTS WITH ACTIVITY HAVE BEEN IN THE 30-40 KT RANGE. COMPLEX WILL CONTINUE EASTWARD BUT MAY LOSE SOME PUNCH AS IT STRAYS AWAY FM GRADIENT OF MLCAPE. H85-H3 THICKNESSES SUGGEST ANY STONGER LINEAR SEGMENTS MAY TRY TO DRIFT ESE AS THE COMPLEX PUSHES NEAR IWD WITHIN THE NEXT 2-3 HRS. NO REAL BIG CHANGE TO PREVIOUS FCST...THOUGH THAT IS PARTIALLY DUE TO A LOT OF SCENARIOS OFFERED UP BY VARIOUS GUIDANCE ON HOW THIS COMPLEX WILL TRANSLATE TO THE EAST THE NEXT FEW HOURS. WENT WITH A CONSENSUS FM ALL THE SOLUTIONS ALONG WITH PREVIOUS FCST. OVERALL FEEL FAIRLY CONFIDENT THAT BTWN ONGOING/STRONG H85 MOISTURE TRANSPORT ON NOSE OF H85 JET AND DIVERGENCE ALOFT...THAT THE OVERALL COMPLEX WILL CONTINUE TO TRACK ON A GENERAL EASTWARD MOVEMENT ACROSS UPR MICHIGAN THROUGH EARLY AFTN...ON SOUTH EDGE OF SHORTWAVE MOVING ACROSS NORTHERN LK SUPERIOR AND STILL WELL TO NORTH OF SFC WARM FRONT. LATEST RENDITION OF RAPID REFRESH RUC /HRRR/ SHOWS THIS PRETTY WELL AND INDICATES THAT MAJORITY OF PRECIP WILL BE DONE BY EARLY AFTN OVR WEST HALF AND SOON THERE AFTER IN THE EAST. WHAT HAPPENS BY MID TO LATE AFTN IS A CONCERN AS MODELS HAVE CERTAINLY TRENDED FARTHER NORTH WITH ADVANCING SFC WARM FRONT BY MID-LATE AFTN. SINCE IT APPEARS NOW THAT BULK OF CONVECTIVE COMPLEX THIS MORNING WILL JUST GRAZE SOUTHERN CWA IT IS MORE FEASIBLE THAT SOUTHERN CWA MAY SNEAK INTO WARM SECTOR THIS AFTN AND WITH GRADIENT OF 0-6KM MUCAPE WELL OVR 2000 J/KG OVERHEAD ALONG WITH ANOTHER SHORTWAVE WORKING THROUGH IN SPEEDY WESTERLY FLOW IN ADDITION TO MORE UPPER DIVERGENCE ALOFT...BEGINNING TO THINK AN ADDITIONAL ROUND OF SHRA/TSRA MAY DEVELOP BY LATE AFTN. IF CONVECTION BEHAVES LIKE IT HAS OVERNIGHT WITH MOST ACTIVITY OCCURRING ON GRADIENT OF MLCAPE...THEN PORTIONS OF CWA WOULD BE FAVORED FOR STRONG TSRA LINE SEGMENTS WITH STRONG/GUSTY WINDS. A LOT WILL DEPEND ON HOW QUICKLY COMPLEX MOVES THROUGH TODAY AND EXTENT OF DESTABILIZATION THAT CAN OCCUR LATE TODAY. THREAT FOR STORMS COULD LINGER INTO THE EVENING. LATER TONIGHT...STRONG UPPER LOW CURRENTLY OVR SOUTHERN SASKATCHEWAN WILL BE APPROACHING. H7-H3 Q-VECTOR CONVERGENCE AHEAD OF UPR LOW COULD TRIGGER ELEVATED CONVECTION. TROUBLE IS MOISTURE IS HEAVY IN THE LOW-LEVELS BUT REALLY DRYING OUT IN THE MID-UPR LEVELS. KEPT SOME SLIGHT CHANCES IN FCST BUT BETTER CHANCES LIKELY HOLD OFF TIL AFTER DAYBREAK ON THURSDAY. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 439 AM EDT WED JUL 25 2012 BEGINNING OF THE PERIOD WILL INCLUDE A CLOSED 500MB LOW OVER NORTHERN MN THAT WILL TRACK SOUTHEASTWARD WHILE LOSING STRENGTH...CROSSING THE UPPER GREAT LAKES BY NIGHTFALL. AS IT NEARS...MODEL SOUNDINGS ARE HINTING AT ABUNDANT LEFTOVER MOISTURE FROM WEDNESDAY/S EXITING SYSTEM...SO WILL CONTINUE WITH PREVIOUS FORECASTS MENTION OF CLOUDY SKIES...COOLER CONDITIONS...AND A SLIGHT CHANCE FOR SHRA. THICK CLOUD COVER FROM THE LOW LEVELS UPWARDS WILL PREVENT MUCH IN THE WAY OF RADIATIVE HEATING...SO WILL KEEP TEMPS BELOW NORMAL...BARELY REACHING THE 70 MARK NEAR LAKE SUPERIOR. ALL MODELS SEEM TO BE IN GOOD AGREEMENT OF SOME PRECIP TRAVERSING UPPER MI THURSDAY NIGHT AS A RESULT OF THIS UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE WARM FRONT. THOUGH PWAT VALUES ARE ONLY 100-120 PERCENT OF NORMAL...ABUNDANT LINGERING MOISTURE MENTIONED ABOVE SHOULD BE ENOUGH TO SPARK SOME PRECIP ALONG THE MAIN LINE OF CONVERGENCE/WARM FRONT/ AS IT PASSES OVER. HOWEVER...A PROBLEM PERSISTS ON THE EXACT LOCATION OF THE PRECIP AND CONVERGENCE...AS EVERY MODEL SEEMS TO HAVE A SLIGHTLY DIFFERENT SOLUTION IN WHICH PART OF UPPER MI WILL SEE THE BEST RAINFALL CHANCES THURSDAY NIGHT INTO FRIDAY. LATEST NAM SHOWS BEST MU CAPE VALUES TO ARRIVE WITH THE ONSET OF THE FRONTAL PASSAGE AND DIMINISH DURING THE OVERNIGHT HOURS /BY 03Z/...WITH HIGHEST VALUES /1-1.5 J/KG/ NEAR THE WISCONSIN BORDER. HOWEVER 0-3KM COMPUTED CAPE VALUES ONLY TOP OUT BETWEEN 2-300 J/KG...WITH THE NAM FORECASTED CAPE PROFILE VERY LONG AND SKINNY...INDICATIVE OF ONLY ISOLATED CHANCES. TO SUM UP THEN...A FEW RUMBLES OF THUNDER AND FLASHES OF LIGHTNING COULD BE POSSIBLE DURING THE EVENING WHEN INSTABILITY IS AT ITS BEST...BUT OTHERWISE AM LEANING TOWARDS THIS MAINLY BEING A HEAVY RAIN EVENT. 500MB SHORTWAVE WILL CONTINUE TO WEAKEN AS IT EXITS INTO THE LOWER GREAT LAKES DURING THE DAY FRIDAY. HOWEVER...LINGERING MOISTURE WILL MAKE FOR SIMILAR CONDITIONS TO THURSDAY...WITH THICK CLOUD COVER AND NRLY WINDS MAKING FOR MOIST AND COOLER THAN NORMAL CONDITIONS. MANY LOCATIONS WILL STRUGGLE TO GET INTO THE 70S. WITH THIS SET UP...WILL CONTINUE WITH SLIGHT CHANCE POPS DURING THE DAY FRIDAY IN THE WEST AND CENTRAL...IN THAT SOME LEFT OVER FORCING COULD BE ENOUGH TO SPAWN SOME SHRA/TSRA...WHILE BEST FORCING AND PRECIP CHANCES WILL LIE NEAR LAKE MICHIGAN. 500MB RIDGING PATTERN OVER THE NORTHERN PLAINS WILL BEGIN TO MOVE EASTWARD...WORKING ITS WAY INTO THE WESTERN PORTIONS OF THE CWA BY LATE FRIDAY AFTERNOON AS IS SEEN ON THE FORECAST SOUNDINGS...FIRST STARTING IN THE UPPER LEVELS AND THEN WORKING ITS WAY DOWN TO THE SURFACE. THIS WILL TRANSLATE TO RAPIDLY CLEARING SKIES FROM WEST TO EAST DURING THE OVERNIGHT HOURS AND LOWS DROPPING TO THE LOW TO MID 50S INLAND AWAY FROM THE WARMER LAKE INFLUENCE. 500MB RIDGE AND ASSOCIATED HIGH PRESSURE WILL CONTINUE TO DOMINATE THROUGH THE DAY ON SUNDAY. THIS WILL TRANSLATE TO MOSTLY SUNNY SKIES ACROSS THE REGION...LIGHT SOUTHERLY WINDS...AND HIGH TEMPERATURES RISING TO BACK ABOVE NORMAL. THE 500MB RIDGE SHOULD REMAIN IN PLACE THROUGHOUT THE REST OF THE FORECAST PERIOD...WITH SEVERAL WEAK SHORTWAVES TRAVERSING THE RIDGE AND UPPER GREAT LAKES. ALL LONG RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT SHORTWAVE AND RESULTING PRECIP WILL TRAVERSE THE UPPER GREAT LAKES SUNDAY EVENING INTO MONDAY WITH PW VALUES JUMPING BACK UP TO 100-120 PERCENT OF NORMAL. UNFORTUNATELY...AFTER THIS POINT MODELS START TO LOSE AGREEMENT ON TIMING AND LOCATIONS OF MENTIONED PRECIP SO WENT WITH MODEL CONSENSUS FOR REMAINDER OF FORECAST PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 747 AM EDT WED JUL 25 2012 SHRA/TSRA WORKING THROUGH UPPER MICHIGAN. EXPECT CONDITIONS TO DETERIORATE THROUGH THE DAY. RAIN COULD BE HEAVY AT TIMES...WITH VSBY LIKELY REDUCED TO AT LEAST MVFR RANGE THRU THE MORNING. SHOULD BE PRETTY QUICK LOWERING OF CIGS AS WELL INTO THE IFR RANGE AT BOTH CMX AND SAW. SLIGHTLY HIGHER CIGS AT IWD DUE TO LESS FAVORABLE EAST FLOW. EXPECT CONDITIONS TO DROP TO IFR/LIFR TNGT AT ALL SITES WITH LLVL MSTR LINGERING UNDER LGT UPSLOPE WIND COMPONENT OFF LK SUP/SOME MID LVL DRYING IN THE WAKE OF DEPARTING DISTURBANCE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 439 AM EDT WED JUL 25 2012 LOW PRESSURE SYSTEM MOVES INTO WISCONSIN LATER TODAY AND INTO THE EASTERN GREAT LAKES ON THURSDAY MORNING AND INTO THE NEW ENGLAND STATES ON FRIDAY. THIS WILL LEAVE A WEAK SFC TROUGH OVER THE UPPER GREAT LAKES LATER TONIGHT THROUGH FRIDAY. HIGH PRESSURE WILL THEN MOVE OVER THE UPPER GREAT LAKES THIS WEEKEND...LEADING TO LIGHT WINDS OVER LK SUPERIOR. SOME STRONG E/SE WINDS POSSIBLE TODAY OVR EASTERN AND NORTHERN SECTIONS OF LK SUPERIOR OUT AHEAD OF THE LOW MOVING THROUGH AND THEN GUSTY ENE WINDS THIS EVENING IN WAKE OF THE LOW. OVERALL THOUGH...EXPECT WINDS TO STAY BELOW 20 KTS THROUGH THE WEEKEND. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLA LONG TERM...JMW AVIATION...JLA MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
948 AM CDT WED JUL 25 2012 .UPDATE... NOW THAT MUCH OF THE RAIN HAS MOVED OUT OF THE EASTERN FA WITH THE LOW PRESSURE SYSTEM MOVING THROUGH THE MINNESOTA AND WESTERN LAKE SUPERIOR REGION...UPDATED THE GRIDS THROUGH THIS EVENING. THINK THE LINGERING RAIN AND THUNDER WILL CONTINUE TO MOVE OUT OF THE EASTERN FA THIS MORNING...AND ANOTHER CLUSTER OF RAIN AND THUNDER IN CENTRAL MN WILL MOVE ACROSS THE SOUTHERN FA THIS MORNING AS IT FALLS APART. THIS IS SUPPORTED BY RECENT HRRR AND NAM MODEL RUNS. THEN FOR THIS AFTERNOON...THERE ARE TWO MAIN AREAS WHERE THERE MAY BE REDEVELOPMENT OF STORMS. THE NAM/WRF/HRRR ARE IN FAIRLY GOOD AGREEMENT THAT THERE MAY BE REDEVELOPING STORMS NEAR OR JUST SOUTHEAST OF THE SOUTHEASTERN FA THIS AFTERNOON NEAR THE COLD FRONT MOVING THROUGH THE REGION. ALSO...THERE MAY BE STORMS LATE THIS AFTERNOON OR THIS EVENING IN THE WESTERN FA NEAR THE SECONDARY COLD FRONT ASSOCIATED WITH THE POTENT SHORTWAVE COMING OUT OF CANADA. BOTH AREAS COULD SEE SOME STRONG...MAYBE SEVERE...THUNDERSTORMS DUE TO ADEQUATE INSTABILITY AND SHEAR. KEPT LOW CHANCES OF PCPN FOR THE REST OF THE FA THROUGH THIS EVENING TO ACCOUNT FOR ANY MARGINS OF ERROR. && .PREV DISCUSSION... /ISSUED 647 AM CDT WED JUL 25 2012/ AVIATION.../12Z TAF ISSUANCE/ CLOUD AND VSBY CONDITIONS WILL BE QUITE VARIABLE FOR A TIME THIS MORNING BEFORE BECOMING GENERALLY VFR AS THE DAY WEARS ON. THE NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN PORTION OF THE AREA WILL GRADUALLY GIVE WAY TO SCATTERED SHOWERS AND STORMS. DRIER AIR WILL WORK IN FROM THE WEST THIS AFTERNOON...BUT SOME SHOWERS AND STORMS WILL STILL BE AROUND. PREV DISCUSSION... /ISSUED 358 AM CDT WED JUL 25 2012/ SHORT TERM...LATEST REGIONAL RADAR MOSAIC SHOWS WIDESPREAD SHOWERS AND STORMS OVERSPREADING OUR MN ZONES EARLY THIS MORNING...WITH SCTD SHOWERS AND STORMS ACROSS OUR WI ZONES. THIS ACTIVITY IS ASSOCIATED WITH A FAIRLY STRONG SHORTWAVE PROPAGATING EWD ACROSS THE MIDWEST EARLY THIS MORNING. WITH MUCAPE VALUES RANGING FROM 1000-3000 J/KG AND SRH VALUES RANGING FROM 200 TO 400 M2/S2 ACROSS THE REGION...INITIALLY THE CONVECTION WAS QUITE ORGANIZED ACROSS WRN MN RESULTING IN ISOLD SVR STORMS. CURRENTLY THE STRENGTH OF THE CONVECTION HAS WEAKENED WITH HEAVY RAIN BEING THE MAIN CONCERN AS IT SPREADS EAST ACROSS OUR CWA. THE LATEST SPC RUC ANALYSIS SHOWS PWAT VALUES RANGING FROM 1.5 TO 2 INCHES ACROSS MOST OF THE CWA. HOWEVER WITH THE FLOW ALOFT BEING FAIRLY PROGRESSIVE...THE RAIN SHOULD TAPER OFF FROM THE WEST BY THIS AFTERNOON...AND END ACROSS OUR SERN ZONES THIS EVENING. EVEN SO...WE WILL KEEP THE FF WATCH IN EFFECT FOR THE NORTHSHORE DUE TO PREVIOUS FLOOD DAMAGE FROM A MONTH AGO AND FAST REACTING STREAMS/CREEKS THE NORTHSHORE. A RESPITE IN THE PRECIPITATION IS EXPECTED FOR TONIGHT BEFORE A POTENT UPPER TROUGH OVER SRN CANADA IS PROGGED TO DIG SEWD OVER THE NORTHLAND ON THURSDAY. THE SECOND ROUND OF SHOWERS AND STORMS SHOULD BE FAIRLY WIDESPREAD...BUT NOT AS STRONG OR HEAVY. TEMPERATURES TODAY SHOULD BE SEASONABLY WARM IF THERE ARE SOME BREAKS IN THE RAIN AND CLOUD COVER. HOWEVER WITH THE UPPER TROUGH OVER THE WRN GREAT LAKES TOMORROW...TEMPS WILL BE SEASONABLY COOL WITH HIGHS ONLY IN THE LOWER TO MID 70S FOR MOST LOCATIONS. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. A SHORTWAVE WILL CONTINUE TO MOVE THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY...WITH SOME LINGERING SHOWERS AND THUNDERSTORMS. WE WILL CONTINUE IN A GENERAL NW FLOW PATTERN FROM LATE IN THE WEEK INTO THE WEEKEND. IN GENERAL...THERE WILL CONTINUE TO BE A CHANCE OF SHOWERS AND THUNDERSTORMS FOR MOST OF THE PERIODS DURING THE EXTENDED TIME FRAME. TEMPERATURES WILL CONTINUE TO BE QUITE WARM...WITH 80S TO LOWER 90S THROUGHOUT THE PERIOD. NOT REALLY A LOT OF FEATURES THROUGHOUT THE EXTENDED PERIOD...SO MAINLY LOOKING AT SOME DIURNAL PRECIPITATION DUE TO SUBTLE FEATURES. AVIATION.../06Z TAF ISSUANCE/ CONDITIONS DETERIORATING TO IFR IN AREAS OF HEAVY RAIN AND THUNDERSTORMS. CONDITIONS AGAIN IMPROVING TO LOW-END VFR WITH SCATTERED MVFR IN SHOWERS LATE WEDNESDAY MORNING...THEN VFR WITH SCATTERED CLOUDS AND ISOLATED SHOWERS WEDNESDAY EVENING. && .POINT TEMPS/POPS... DLH 76 59 73 57 / 30 30 70 50 INL 79 56 72 55 / 20 40 70 40 BRD 83 62 77 59 / 50 20 60 20 HYR 83 59 78 58 / 50 20 60 50 ASX 80 59 76 59 / 50 20 60 50 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...GROCHOCINSKI LONG TERM....MELDE
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
648 AM CDT WED JUL 25 2012 .AVIATION... FOR THE 12Z TAFS...VFR CONDITIONS AND SOUTHERLY FLOW ARE EXPECTED TO PERSIST THROUGH THE VALID FORECAST PERIOD. THE EARLY MORNING STRATUS WAS CREEPING UP THE INTERSTATE 35 CORRIDOR SOUTH OF WACO HAS DISSIPATED AS OF 1130Z. SOME MVFR CIGS REMAIN IN PLACE SOUTHEAST OF WACO...BUT THIS BAND OF STRATUS WAS BUILDING NORTHEAST AWAY FROM THE AIRPORT PER INFRARED SATELLITE IMAGERY. AS A RESULT PULLED MENTION OF MVFR CIGS OUT OF THE WACO TAF THIS MORNING AND REMOVED MENTION OF SCATTERED LOW CLOUDS ACROSS THE METROPLEX BASED ON EARLY MORNING SATELLITE TRENDS. EXPECT SOUTHERLY FLOW TO STRENGTHEN A BIT AFTER A FEW HOURS OF HEATING. RAP FORECAST SOUNDINGS INDICATE THAT THE ENVIRONMENT WILL BE UNCAPPED OVER NORTH AND CENTRAL TX THIS AFTERNOON...WHICH ALLOWS THIS MODEL TO INITIATE SOME ISOLATED THUNDERSTORM ACTIVITY DURING THE PEAK HEATING HOURS OF THE DAY. AT THIS TIME THINK THAT THE RAP IS OVERESTIMATING THE QUALITY AND DEPTH OF LOW LEVEL MOISTURE FIELDS AS ALMOST ALL OTHER GUIDANCE INDICATES LOW LEVEL MOISTURE MIXING OUT DURING PEAK HEATING. THINK THAT WE HAVE ENOUGH MOISTURE IN PLACE TO SEE A CUMULUS FIELD DEVELOP THIS AFTERNOON...BUT THINK THAT LOW LEVEL MOISTURE MIXING OUT WILL KEEP US CAPPED NEAR AREA AIRPORTS FOR THE NEXT 24 HRS. CAVANAUGH && .PREV DISCUSSION... /ISSUED 313 AM CDT WED JUL 25 2012/ AT 00Z...HIGH PRESSURE WAS ANALYZED ON UPPER AIR CHARTS ACROSS THE SOUTHEASTERN CONUS...WITH ANOTHER HIGH CENTER ACROSS THE DESERT SOUTHWEST. A STRONG TROUGH IS CURRENTLY IN SOUTHERN CANADA...AND A WEAKER TROUGH AXIS IS CURRENTLY OVER WEST TX AND THE PANHANDLE. WITH THIS SETUP...MOSTLY DRY WEATHER IS EXPECTED TODAY FOR NORTH TEXAS...WITH RAIN CHANCES TO OUR WEST. 850 TEMPS WILL BE WARMER THIS AFTERNOON AND HIGHS TODAY WILL TOP OUT A DEGREE OR TWO HIGHER THAN YESTERDAY. WINDS TODAY ARE EXPECTED TO BE BREEZY DUE TO A STRENGTHENING SURFACE LOW IN THE CENTRAL PLAINS. WITH MINIMUM HUMIDITY VALUES NEAR OR BELOW 30 PERCENT WEST OF INTERSTATE 35...ELEVATED FIRE WEATHER CONDITIONS ARE EXPECTED. AS WE MOVE INTO TOMORROW...THE UPPER TROUGH IN CANADA WILL MOVE THROUGH THE NORTHERN PLAINS. THE RIDGE ACROSS THE SOUTHEAST WILL THEN BE FORCED TO WEAKEN AND REESTABLISH FURTHER TO THE EAST AND THE SOUTHWEST RIDGE WILL STRENGTHEN/AMPLIFY ON THE BACKSIDE OF THE EASTWARD MOVING TROUGH. THIS PATTERN PLACES OKLAHOMA UNDERNEATH A DEFORMATION AXIS FOR THURSDAY AFTERNOON. WITH LITTLE INHIBITION AND AMPLE INSTABILITY...SCATTERED THUNDERSTORMS ARE EXPECTED NORTH OF THE RED RIVER. MOST ACTIVITY SHOULD REMAIN IN OKLAHOMA...BUT ANY SOUTHWARD MOVING BOUNDARIES COULD IGNITE A FEW STORMS IN OUR NORTHERN COUNTIES AND WILL CONTINUE THE 20 POPS FOR THURSDAY. BY FRIDAY...THE RIDGE ACROSS THE WESTERN CONUS WILL STRENGTHEN AND SHIFT SOUTHEAST CONTINUING BEHIND THE TROUGH MOVING ACROSS THE MIDWEST. THIS EQUATES TO THE DEFORMATION AXIS SETTING UP FURTHER TO THE SOUTH...AND SHOULD BE IN OUR NORTHERN CWA. NO CAP IS EXPECTED AND ISOLATED TO SCATTERED CONVECTION SHOULD OCCUR MAINLY IN THE AFTERNOON TO EARLY EVENING HOURS. SHEAR IS EXPECTED TO BE MINIMAL AND INDIVIDUAL UPDRAFTS SHOULD QUICKLY WEAKEN. WITH CLOUD BASES AROUND 7KFT...CANT RULE OUT 40-60 MPH DOWNBURST WINDS WITH COLLAPSING THUNDERSTORMS. HIGHS FRIDAY SHOULD STAY BELOW THE CENTURY MARK WITH THE EXTRA CLOUD COVER AND STORMS AROUND. FOR SATURDAY...THE UPPER RIDGE WILL CONTINUE TO MOVE SOUTHEAST AND CENTER ITSELF ACROSS THE AREA...THUS ENDING THE RAIN CHANCES AND INCREASING TEMPERATURES. THE RIDGE IS NOT EXPECTED TO MOVE MUCH THROUGH THE END OF THE PERIOD AND A STREAK OF 100 DEGREE DAYS IS EXPECTED BEGINNING SATURDAY. A HEAT ADVISORY MAY BE NEEDED FOR THE METROPLEX THIS WEEKEND...AS AFTERNOON HEAT INDICES ARE ABOVE 105 DEGREES AND MORNINGS LOWS REMAIN ABOVE 78 DEGREES. 85/NH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 99 79 100 79 99 / 0 5 10 10 20 WACO, TX 99 78 97 77 98 / 0 5 10 10 10 PARIS, TX 98 74 98 76 96 / 0 5 10 10 30 DENTON, TX 100 77 100 75 99 / 0 5 20 20 30 MCKINNEY, TX 98 76 100 74 98 / 0 5 10 10 20 DALLAS, TX 99 80 100 79 99 / 0 5 10 10 20 TERRELL, TX 98 76 98 75 99 / 0 5 10 10 20 CORSICANA, TX 99 77 97 76 99 / 0 5 10 10 10 TEMPLE, TX 97 74 97 73 98 / 0 5 10 10 10 MINERAL WELLS, TX 101 75 100 75 99 / 0 5 10 10 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
633 AM CDT WED JUL 25 2012 .AVIATION... VFR CONDITIONS WILL CONTINUE THROUGH THE DAY. BY EARLY AFTERNOON...ISOLATED TO SCATTERED THUNDERSTORMS MAY DEVELOP NEAR THE KLBB TERMINAL AND EVENTUALLY SPREAD TOWARDS THE KCDS TERMINAL. PRECIPITATION SHOULD END BEFORE MIDNIGHT LEAVING VFR CONDITIONS IN PLACE. JORDAN && .PREV DISCUSSION... /ISSUED 403 AM CDT WED JUL 25 2012/ SHORT TERM... 00Z UPPER-AIR ANALYSIS AND WV SATELLITE SHOWS CONSIDERABLE MOISTURE IN PLACE ACROSS THE REGION. KAMA AND KMAF RESPECTIVELY HAVE 1.14 AND 1.11 INCH PRECIPITABLE WATER VALUES WHICH IS SOMEWHAT HIGH FOR THIS TIME OF YEAR. ALSO ARE SEEING SOME SHOWERS EARLY THIS MORNING ON THE RADAR ASSOCIATED WITH AN AREA OF MID-LEVEL CLOUD COVER. UPPER-AIR ANALYSIS SHOWS A TROF AXIS LOCATED ACROSS EASTERN NEW MEXICO THIS MORNING WITH THE MODELS SLOWLY SHIFTING THIS TOWARDS THE STATE LINE THROUGH THE DAY. MONSOON MOISTURE PLUME SHOULD MOVE BACK OVER THE WESTERN HALF OF THE FORECAST AREA THIS AFTERNOON AND DAYTIME HEATING SHOULD HELP TO DESTABILIZE THE ATMOSPHERE RESULTING IN A BIT MORE WIDESPREAD STORM ACTIVITY COMPARED TO YESTERDAY. ALL OF THIS IS ACCORDING TO THE VARIOUS RESOLUTIONS OF THE NAM MODEL AND TO LESSER EXTENT THE TTU WRF. THE GFS AND LATEST HRRR ARE NOT AS OPTIMISTIC AT ALL. WILL KEEP CHANCE OF THUNDERSTORMS OVER THE CENTRAL SOUTH PLAINS WHERE THE INSTABILITY AXIS MAY TRY TO SET UP THIS AFTERNOON AND THEN SHIFT THIS AREA WEST FOR EARLY TONIGHT. THERE COULD BE A FEW SHOWERS THAT LINGER ACROSS THE AREA INTO THURSDAY MORNING AS MONSOON MOISTURE AND TROF AXIS REMAIN NEAR THE REGION. HIGH TEMPERATURES CAME IN A BIT WARMER ON THE MOS GUIDANCE AND WILL KEEP THINGS A FEW DEGREES UNDER THIS DUE TO THE EXPECTED CLOUD COVER AND SHOWERS. JORDAN LONG TERM... THE EXTENDED FORECAST WILL BE PUNCTUATED BY MORE SUMMER HEAT...THOUGH THUNDERSTORMS MAY ALSO GIVE SOME LOCATIONS BRIEF RELIEF THURSDAY AND/OR FRIDAY. A SHORTWAVE TROUGH WILL GLIDE ACROSS THE MIDWEST ON THURSDAY...JUST GRAZING THE SOUTHERN PLAINS WITH WEAK 500-300 MB LAYER Q-VECTOR CONVERGENCE AND DRAWING THE MONSOONAL MOISTURE PLUME ACROSS WEST TEXAS. AT THE SAME TIME...THE TAIL END OF A COLD FRONT WILL EDGE TOWARD OR INTO THE AREA. THE 00Z GFS AND NAM DO HAVE THE THE WIND SHIFT ROUGHLY BISECTING THE FA FROM SW TO NE MIDDAY THURSDAY BEFORE STALLING OUT...WHILE THE ECMWF IS SOMEWHAT FURTHER NORTH...INTO THE TEXAS PANHANDLE. GIVEN THAT THE POSITION OF THE FRONTAL ZONE IS SOMEWHAT IN QUESTION...DETAILS IN CONVECTIVE INITIATION ALSO REMAIN SOMEWHAT UNCERTAIN...BUT WITH WEAK UPPER SUPPORT AND A RELATIVELY MOIST ATMOSPHERE IN PLACE /PWATS AT 130 TO OVER 150 PERCENT OF AVERAGE/...EXPECT DAYTIME HEATING TO LEAD TO SCATTERED AFTERNOON AND EVENING CONVECTION. PROGGED SFC MOISTURE AND RESULTANT INSTABILITY WILL BE A LITTLE HIGHER THAN WE HAVE SEEN RECENTLY THOUGH DEEP-LAYER SHEAR WILL STILL BE RATHER MEAGER. HENCE...DO NOT ANTICIPATE MUCH STORM ORGANIZATION...BUT COULD SEE A FEW STRONGER CORES THAT COULD PRODUCE SMALL HAIL...STOUT DOWNBURST WINDS AND LOCALLY HEAVY RAINS. ANY WEAK UPPER SUPPORT THURSDAY WILL QUICKLY WANE FRIDAY AS AN UPPER LEVEL RIDGE STRENGTHENS AND EXTENDS EASTWARD FROM THE SOUTHERN ROCKIES INTO THE SOUTHERN PLAINS. STILL...RESIDUAL LOW-LEVEL MOISTURE...A THINNING MID-LEVEL MOISTURE PLUME...STRONG HEATING AND PERHAPS A SFC BOUNDARY IN THE AREA MAY BE ENOUGH TO GENERATE ISOLATED TO WIDELY SCATTERED CONVECTION FRIDAY AFTERNOON AND EVENING. BEYOND THAT...THOUGH...THE UPPER RIDGE WILL BECOME CENTERED ACROSS THE SOUTHERN PLAINS AND IT SHOULD PUT THE KIBOSH ON STORM CHANCES THIS WEEKEND AND INTO AT LEAST THE FIRST PART OF NEXT WEEK AS IT PROMOTES SUBSIDENCE AND SHIFTS THE MONSOON MOISTURE BACK TO THE WEST. THE UPPER RIDGE AXIS MAY ATTEMPT TO SHIFT BACK WEST OF THE AREA BY DAY 7 OR DAY 8 IF THE GFS IS CORRECT...BUT THE ECMWF KEEPS THE CENTER OF THE HIGH NEARBY THROUGH THE REMAINDER OF NEXT WEAK. THUS...EXPECT HOT TEMPERATURES TO CONTINUE...AND HAVE FAVORED HIGHS SLIGHTLY ABOVE GUIDANCE FROM THIS WEEKEND ONWARD...GIVEN RECENT GUIDANCE BIASES WITH THE PREVIOUS UPPER RIDGE ACROSS THE SOUTH PLAINS THIS PAST WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 95 67 94 66 92 / 20 30 30 30 20 TULIA 94 68 96 67 92 / 20 30 30 30 20 PLAINVIEW 94 69 94 69 92 / 30 20 30 30 20 LEVELLAND 95 69 95 69 93 / 30 20 30 30 20 LUBBOCK 96 71 96 71 95 / 30 20 30 30 20 DENVER CITY 96 70 96 69 94 / 20 20 30 30 20 BROWNFIELD 95 71 96 69 94 / 30 20 30 30 20 CHILDRESS 100 75 100 74 99 / 20 20 30 30 20 SPUR 97 72 98 72 100 / 30 20 30 30 20 ASPERMONT 99 76 102 76 101 / 30 20 30 30 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
611 AM CDT WED JUL 25 2012 .SHORT TERM...TODAY THROUGH FRIDAY 259 AM CDT WED JUL 25 2012 FORECAST CONCERNS ARE ON DANGEROUS HEAT TODAY AND CHANCES FOR SEVERE THUNDERSTORM THROUGH THIS EVENING. FOCUS THEN TURNS TO SHOWER AND THUNDERSTORM CHANCES ON THURSDAY...WITH THE POTENTIAL FOR A FEW ISOLATED SEVERE STORMS. LATEST RADAR IMAGERY SHOWED WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND NORTHERN MINNESOTA. SOME OF THESE STORMS HAVE BECOME SEVERE...ORGANIZING INTO LINE STRUCTURES...AND CAPABLE OF PRODUCING DAMAGING WINDS AND HEAVY RAINFALL. THE ONGOING MCS ACROSS NORTHWEST AND NORTHERN WISCONSIN EARLY THIS MORNING COULD POSSIBLY TURN EAST SOUTHEAST AND IMPACT LOCATIONS NORTH OF INTERSTATE 94. THIS LINE OF STORMS WILL BE CAPABLE OF PRODUCING DAMAGING WINDS. OTHERWISE...HOT TEMPERATURES WILL BE SEEN ACROSS NORTHEAST IOWA...SOUTHWEST WISCONSIN AND PORTIONS OF SOUTHEAST MINNESOTA TODAY...WHERE HEAT INDEX VALUES WILL RANGE FROM 100 TO 105 THIS AFTERNOON. ISOLATED AREAS OF HEAT INDICES OF 110 ARE POSSIBLE. SURFACE LOW PRESSURE WILL MOVE INTO WESTERN SECTIONS OF SOUTHEAST MINNESOTA LATE THIS MORNING. MEANWHILE...A WARM FRONT WILL BE IN PLACE ACROSS NORTHERN WISCONSIN...JUST NORTH OF THE HIGHWAY 29 CORRIDOR...WHILE A COLD FRONT WILL EXTEND FROM NORTHWEST WISCONSIN THROUGH SOUTH CENTRAL MINNESOTA INTO FAR NORTHEAST IOWA. THIS WILL LEAVE MUCH OF THE FORECAST AREA IN THE WARM SECTOR WITH A PERIOD OF SUNNY SKIES AND HOT TEMPERATURES SOUTH OF I-94. THE COLD FRONT WILL PUSH SOUTHEAST INTO THE AREA THIS AFTERNOON. BREEZY SOUTHWEST WINDS ARE EXPECTED TODAY AHEAD OF THE FRONT WITH WIND SPEEDS OF 15 TO 25 MPH WITH GUSTS IN THE 28 TO 35 MPH RANGE POSSIBLE...ESPECIALLY ALONG THE BLUFF TOPS NEAR THE MISSISSIPPI RIVER AND THE OPEN AREAS OF NORTHEAST IOWA AND SOUTHEAST MINNESOTA. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT. EXACTLY WHERE THE THE STORMS GO UP ALONG THE FRONT IS SOMEWHAT UNCERTAIN WITH FORECAST MODELS VARYING ON THE EXACT LOCATION. THE NAM SHOWS STORMS DEVELOPING ALONG A LINE EXTENDING FROM NEAR WAUSAU WISCONSIN...TO NEAR LA CROSSE TO CHARLES CITY. THE ECMWF...GFS...AND GEM SHOWS STORMS DEVELOPING FURTHER SOUTH OF THE NAM MAINLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. FORECAST SOUNDINGS CONTINUE TO SHOW INVERTED V TYPE SOUNDING THIS AFTERNOON WITH DEEP MIXING EXPECTED UP TO 700 MB. IF THIS DEEP MIXING IS REALIZED THERE WILL BE AN ENHANCED THREAT FOR DAMAGING WINDS WITH ANY STORMS THAT DEVELOP. FEEL THE DEWPOINT MIXING MAY BE A BIT OVERDONE WITH THE RECENT RAINS ACROSS PARTS OF THE AREA. HOWEVER...LOCATIONS THAT HAVENT SEEN THESE RAINS MAY INDEED SEE MIXING THIS DEEP. THE INSTABILITY COULD BE A BIT UNDERDONE WITH DEWPOINTS MIXING OUT IN THE FORECAST SOUNDINGS. NOT CONSIDERING THIS MIXING OUT...THE NAM SHOWS AFTERNOON 0-3 KM MUCAPE VALUES INCREASING TO 3500 PLUS J/KG RIGHT ALONG THE BOUNDARY WITH DEWPOINTS CLIMBING INTO THE UPPER 70S ALONG THE FRONT. DEEP LAYER SHEAR LAGS BEHIND THE FRONT. THIS COULD HINDER STORM ORGANIZATION FOR THIS AFTERNOON. HOWEVER...STILL CONCERNED ABOUT THE DRY LOW LEVELS AND THE ENHANCED DAMAGING WIND THREAT IF THIS DEEP MIXING OCCURS. THINKING THAT SOME OF THE STORMS WILL BECOME SEVERE THIS AFTERNOON WITH DAMAGING WINDS THE MAIN THREAT AND POSSIBLY LARGE HAIL IF DEEP LAYER SHEAR CAN CATCH UP TO THE FRONT. THERE IS AN OUTSIDE CHANCE OF A BRIEF TORNADO THREAT ALONG THE WARM FRONT EARLY THIS AFTERNOON BEFORE THE WARM FRONT EXITS THE AREA. THIS IS ESPECIALLY THE CASE NEAR THE TRIPLE POINT OVER NORTH CENTRAL WISCONSIN...NORTH OF INTERSTATE 94. THINKING THE CAP WILL BE STRONG ENOUGH TO PREVENT SURFACE BASED CONVECTION BUT WILL HAVE TO KEEP A VERY CLOSE EYE ON THIS. IF SURFACE BASED STORMS FORM NEAR THE FRONT EARLY THIS AFTERNOON THERE WILL BE SUFFICIENT LOW LEVEL SHEAR TO SUPPORT LOW LEVEL STORM ROTATION AND TORNADOES. WILL HAVE TO KEEP A CLOSE WATCH ON THE EXACT TRACK OF THE SURFACE LOW THIS MORNING. THE 00Z NAM IS THE ONLY MODEL SHOWING THE SURFACE LOW STAYING THIS FAR SOUTH. THE ECMWF...GFS...AND GEM TAKE THE LOW ACROSS FAR NORTHERN WISCONSIN. CONCERNED THAT THE ONGOING CONVECTION THIS MORNING COULD HOLD THE WARM FRONT SOUTH AS THE NAM IS SUGGESTING. THE COLD FRONT WILL SLIDE SOUTHEAST OF THE REGION LATE THIS EVENING TAKING WITH SHOWERS AND THUNDERSTORMS TAPERING OFF. SOME OF THE STORMS COULD BE SEVERE THIS EVENING ACROSS NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN WITH DAMAGING WINDS THE MAIN THREAT. AGAIN...IF STORMS WOULD BECOME MORE ORGANIZED A FEW OF THEM COULD PRODUCE LARGE HAIL. PLAN ON OVERNIGHT LOWS RANGING FROM THE LOWER 60S ACROSS NORTHERN WISCONSIN TO AROUND 70 OVER NORTHEAST IOWA. AN UPPER LEVEL TROUGH WILL DIVE INTO NORTHERN MINNESOTA THURSDAY MORNING THEN MOVE SOUTHEAST INTO NORTHERN WISCONSIN THURSDAY AFTERNOON. A WEAK COLD FRONT WILL PUSH ACROSS THE AREA AHEAD OF THE APPROACHING TROUGH. SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE FRONT AS UPPER LEVEL SUPPORT INCREASES WITH THE APPROACHING TROUGH. SURFACE BASED CAPE INCREASES TO AROUND 1400 J/KG AHEAD OF THE FRONT. 0-6 KM SHEAR ISNT OVERLY IMPRESSIVE WITH VALUES RANGING FROM THE 25 TO 30 KTS. COULD SEE A FEW STRONG TO SEVERE STORMS AGAIN THURSDAY AFTERNOON WITH DAMAGING WINDS AND POSSIBLY LARGE HAIL. PLAN ON HIGHS ON THURSDAY RANGING FROM THE LOWER 80S ACROSS NORTHERN WISCONSIN TO THE UPPER 80S OVER NORTHEAST IOWA. COOLER AIR WILL MOVE INTO THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY WITH 850 MB TEMPERATURES FALLING INTO TE 12 TO 14 C RANGE BY FRIDAY AFTERNOON. SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION PROVIDING MOSTLY SUNNY SKIES. PLAN ON HIGH TEMPERATURES RANGING FROM THE UPPER 70S OVER NORTHERN WISCONSIN TO THE LOWER 80S ACROSS NORTHEAST IOWA. .LONG TERM...SATURDAY THROUGH TUESDAY 259 AM CDT WED JUL 25 2012 25.00 MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT ON SATURDAY SHOWING SURFACE HIGH PRESSURE IN CONTROL ACROSS THE FORECAST AREA...WITH NORTHWEST FLOW ALOFT. PLAN ON MOSTLY SUNNY SKIES ON SATURDAY WITH HIGHS IN THE 80S. A SHORTWAVE TROUGH WILL PUSH INTO THE UPPER MISSISSIPPI RIVER VALLEY SATURDAY NIGHT THROUGH SUNDAY BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE AREA. CHANCES FOR SHOWER AND STORMS WILL PERSIST THROUGH TUESDAY AS WEAK EMBEDDED WAVES IN THE NORTHWEST FLOW CONTINUE TO IMPACT THE REGION. FROM SUNDAY THROUGH TUESDAY...PLAN ON HIGHS IN THE 80S TO AROUND 90 WITH OVERNIGHT LOWS FALLING INTO THE 60S. && .AVIATION...TODAY AND TONIGHT 610 AM CDT WED JUL 25 2012 HIGH LEVEL CLOUDS SPILLING OVER BOTH TAF SITES FROM THE ON GOING MCS ACROSS NORTHERN MINNESOTA AND WISCONSIN. EXPECT THESE CLOUDS WILL STAY AROUND FOR MUCH OF THE MORNING BEFORE DISSIPATING. THIS WILL SLOW DOWN THE MIXING AND PUSHED BACK THE TIMING FOR THE WIND GUSTS JUST A LITTLE BIT FROM THE PREVIOUS FORECASTS. 25.06Z NAM BUFKIT SOUNDINGS STILL SHOWING A DEEP WELL MIXED LAYER BEHIND THE WARM FRONT TODAY WITH SOUTHWEST WINDS AND GUSTS TO AROUND 25 KNOTS OR SO. THE AREA OF LOW PRESSURE OVER EASTERN SOUTH DAKOTA WILL MOVE EAST ALONG THE WARM FRONT TODAY BRINGING A COLD FRONT WITH IT. EXPECTING SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG AND BEHIND THE COLD FRONT ONCE THE STRONG CAP IN THE WARM SECTOR IS BROKEN/DISPLACED. THE NAM STILL SUGGESTS THIS WILL OCCUR EAST OF KRST BUT THE 25.08Z RUN OF THE HRRR IS SUGGESTING AT LEAST THE POSSIBILITY OF SOME ACTIVITY AROUND KRST AND HONORED THIS WILL A VCTS. KLSE HAS A MUCH BETTER CHANCE OF SEEING SOME STORMS AND WENT WITH A 2 HOUR TEMPO PERIOD WHEN THE CHANCES SHOULD BE AT THEIR HIGHEST. THE THREAT FOR THE CONVECTION SHOULD END 3 TO 4 HOURS BEHIND THE COLD FRONT WITH THE WINDS COMING AROUND TO THE NORTHWEST. MODEL SOUNDINGS AND GUIDANCE SHOWING THE LOWEST LEVELS BECOMING SATURATED OVERNIGHT WITH FOG DEVELOPING. NOT SEEING ANY OF THIS UPSTREAM BEHIND THE FRONT AT THIS TIME BUT DID CONTINUE THE SCATTERED STRATUS DECK JUST IN CASE. && .ARX WATCHES/WARNINGS/ADVISORIES... 259 AM CDT WED JUL 25 2012 WI...HEAT ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR WIZ054-055-061. HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR WIZ041>044-053. MN...HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR MNZ088-095-096. IA...HEAT ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR IAZ010-011-018-019-029-030. HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR IAZ008-009. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...04
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
337 PM EDT WED JUL 25 2012 .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... MAIN FORECAST CONCERN IS HEAT TODAY AND THURSDAY ALONG WITH CONVECTION DEVELOPMENT BOTH AFTERNOONS. CURRENT TEMPS HAVE BEEN RIGHT ON TRACK WITH FORECAST AND AREAS IN THE SOUTH ARE IN LINE FOR REACHING HEAT ADVISORY CRITERIA...THEREFORE WILL CONTINUE CURRENT PRODUCT. GENERALLY WENT WITH BLEND OF MAV AND MET SOLUTIONS FOR TEMPS INTO TOMORROW NIGHT. AREAS IN THE EAST CENTRAL AND SOUTHEAST PORTIONS LOOK TO AGAIN REACH OVERNIGHT MIN TEMPS OF AT LEAST 75 DEGREES AND PEAK HEAT INDICES OF AT LEAST 105 DEGREES TOMORROW. FOR 850 MB TEMPS...THE GFS HAS SIMILAR VALUES TO SLIGHTLY WARMER FOR THURSDAY AFTERNOON WHILE THE NAM GOES SLIGHTLY COOLER PARTICULARLY IN THE SOUTHWEST PORTION. THIS IS LIKELY DUE TO A SLUG OF TROPICAL MOISTURE AND ASSOCIATED CLOUD COVER PROGGED TO ADVECT NORTHWARD INTO THE AREA FROM THE NE GULF COAST. ATTM IT APPEARS THAT EXTENDING THE CURRENT HEAT ADVISORY INTO THURSDAY EARLY EVENING FOR THE EAST CENTRAL AND SOUTHEAST PORTIONS WOULD BE REASONABLE WITH PERHAPS TRIMMING OUT THE SOUTHWEST. THIS DECISION WILL BE BEST MADE LATER THIS AFTERNOON INTO EARLY EVENING SO AS TO PREVENT CONFUSION WITH CURRENT PRODUCT... THEREFORE PLEASE STAY TUNED TO FUTURE UPDATES. THE OUTFLOW FROM MCS REMNANTS ACROSS THE CAROLINAS EARLIER TODAY HAS SERVED MOSTLY TO STABILIZE THE ENVIRONMENT ACROSS THE EASTERN PORTION OF THE AREA. THE SOUTHERN AND WESTERN PERIPHERIES OF THIS FEATURE MAY FOCUS DEVELOPMENT LATER TODAY...HOWEVER THE HRRR DOES NOT BUY INTO THIS MUCH AND JUST HAS THE MAIN DEVELOPMENT IN THE SOUTHWEST. CURRENT VIS SATELLITE IMAGERY HAS SHOWN SOME CU FIELD ENHANCEMENTS WITH THE ASSOCIATED OUTFLOW AND PERHAPS WEAK GRAVITY WAVES... BUT EARLY SHOWER AND THUNDERSTORM DEVELOPMENT HAS BEEN CLOSER TO THE SW PORTION OF THE AREA. HAVE THEREFORE GONE WITH HIGHER CHANCE POPS IN THE SW TAPERING TO SLIGHT POPS IN THE NW. MLCAPE VALUES OF 2500-3500 J/KG...WEAK VERTICAL WIND SHEAR...AND PW VALUES OF 1.8-2.0 INCHES WILL ALLOW FOR THE MAIN STORM THREATS BEING STRONG WINDS...HEAVY RAINFALL...FREQUENT LIGHTNING...AND SMALL HAIL. ISOLATED SEVERE STORMS ARE POSSIBLE AS WELL... ESPECIALLY IN THE SOUTHWEST WHERE SPC ALSO HAS A SLIGHT RISK ISSUED. WITH THE UPPER RIDGE AXIS OVER THE GREAT LAKES PROGGED TO DAMPEN OUT AND BREAK DOWN...THE ASSOCIATED NW FLOW ALOFT EXTENDING INTO THE CAROLINAS SHOULD WEAKEN AND BECOME MORE ZONAL BY 12Z THURSDAY. THE COMBINATION OF A WEAK LEE SFC TROUGH AND ENHANCED MOISTURE FROM THE ADVECTION OF THE AFOREMENTIONED TROPICAL PLUME IN THE NE GULF WILL ALLOW FOR THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS AGAIN IN THE SOUTH ON THURSDAY. GUIDANCE IS IN GOOD AGREEMENT WITH A DEVELOPING UPPER TROUGH APPROACHING THE NORTHERN PORTION OF THE AREA BY LATE THURSDAY NIGHT...ALONG WITH AN ASSOCIATED SFC FRONT. THIS MAY INCREASE PRECIP POTENTIAL IN THE NORTHERN PORTION THURSDAY NIGHT INTO FRIDAY. 03 .LONG TERM /FRIDAY THROUGH WEDNESDAY/... HAVE MADE NO CHANGES TO THE LONG TERM. MODELS CONSISTEND IN SHOWING A FRONTAL BOUNDARY SINKING INTO THE CWA SATURDAY INTO SUNDAY. NORTH GA MAY BE DRY SATURDAY NIGHT INTO SUNDAY NIGHT BUT MOISTURE RETURNS BY THE FIRST OF THE WEEK. 41 .PREVIOUS DISCUSSION/ISSUED 421 AM WED JUL 25 2012/ HIGH PRESSURE RIDGE OVER THE AREA WEAKENS AND SINKS SOUTH IN THE SHORT TERM. BY FRI...THE RIDGE AXIS IS OVER FL AND THE GULF AND AN APPROACHING COLD FRONT IS MOVING SOUTH OUT OF THE UPPER MS RIVER VALLEY. THIS RIDGE STILL DOMINATES THE WEATHER PATTERN THROUGH THE END OF THE WORK WEEK KEEPING NORTH AND CENTRAL GA IN MOIST WEST TO SOUTHWESTERLY FLOW. PRECIPITABLE WATER VALUES STILL SHOWING NEAR 1.5 TO 1.8 INCH SO HEAVY RAIN WILL STILL BE A CONCERN...AT LEAST THROUGH FRI. DIURNALLY DRIVEN THUNDERSTORMS WILL CONTINUE THROUGH FRIDAY...BUT THEN THINGS BEGIN TO CHANGE SAT. A DEEP CLOSED LOW CENTER TRACKS EAST ACROSS THE GREAT LAKES STATES AND INTO THE NEW ENGLAND STATES THU...WITH ITS ASSOCIATED COLD FRONT MOVING SOUTHWARD. THIS FRONT MOVES INTO NORTH GA BY 00Z SAT AND CONTINUES MOVING SOUTHWARD INTO NORTH FL BY 12Z-18Z SUN. THIS FRONT BRINGS IN A MUCH DRIER AIRMASS AND COOLER TEMPS FOR THE STATE SUN. HAVE BACKED OFF ON POPS FOR SUN TO JUST ISOLATED TSRA MAINLY FOR CENTRAL GA. MOISTURE DOES INCREASE AGAIN MON/TUE SO WILL KEEP ISO/SCT SHRA/TSRA BACK IN THE FORECAST MON/TUE. 01 && .CLIMATE... RECORDS FOR 07-25 MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAHN 101 1981 74 2000 75 1983 61 1947 1952 1911 1912 KATL 102 1995 74 1882 78 2010 60 1882 KCSG 103 1952 82 1998 80 2010 66 1948 1983 KMCN 103 1952 79 1938 79 2010 64 2009 1909 1902 RECORDS FOR 07-26 MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAHN 103 2010 80 1904 76 2005 56 1911 1936 KATL 98 1901 78 1890 77 2005 59 1911 KCSG 99 2010 82 1954 79 1983 66 1948 KMCN 100 2010 80 1957 78 2005 60 1911 1993 && AVIATION... 18Z UPDATE... VFR CONDITIONS EXPECTED THROUGH FORECAST PERIOD WITH SOME REDUCED VSBYS POTENTIALLY OCCURRING WITH ANY TSRA THIS AFTERNOON. BEST CHANCE FOR CONVECTION WILL BE NEAR KMCN AND KCSG AROUND 21Z THEREFORE INCLUDED TEMPO GROUP AT THESE SITES. CHANCE IS TOO LOW AT OTHER SITES TO MENTION BUT THE POTENTIAL FOR ISOLATED TSRA IS STILL THERE. MOSTLY NW WINDS OF 10KTS OR LESS WITH GUSTS NEAR 18KTS CAN BE EXPECTED TO CONTINUE THIS AFTERNOON FOR KATL AND A FEW OTHER SITES. WINDS SHOULD BACK TO MORE WESTERLY OVERNIGHT AT 5-3KTS. FOR CIGS... EXPECT SCT TO FEW AT NEAR 4 KFT DURING DAYTIME HOURS AND INCREASE TO BKN NEAR ANY STORM DEVELOPMENT. //ATL CONFIDENCE...18Z UPDATE... MEDIUM CONFIDENCE ON TIMING OF CONVECTION IN SOUTH. HIGH CONFIDENCE ALL ELSE. 03 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 73 98 74 98 / 20 20 20 30 ATLANTA 76 96 75 94 / 10 30 20 40 BLAIRSVILLE 68 91 69 90 / 10 20 20 50 CARTERSVILLE 72 96 73 94 / 10 20 20 50 COLUMBUS 76 95 75 93 / 20 40 30 40 GAINESVILLE 74 93 74 94 / 20 20 20 40 MACON 75 96 74 97 / 20 40 30 30 ROME 73 97 73 94 / 10 20 20 50 PEACHTREE CITY 73 95 73 94 / 10 30 20 40 VIDALIA 78 100 77 97 / 20 30 20 30 && .FFC WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR THE FOLLOWING ZONES: BALDWIN...BIBB...BLECKLEY...CHATTAHOOCHEE...CRAWFORD... CRISP...DODGE...DOOLY...EMANUEL...GLASCOCK...GREENE...HANCOCK... HARRIS...HOUSTON...JEFFERSON...JOHNSON...JONES...LAURENS... MACON...MARION...MONROE...MONTGOMERY...MUSCOGEE...PEACH... PULASKI...PUTNAM...SCHLEY...STEWART...SUMTER...TALBOT... TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TREUTLEN...TWIGGS... UPSON...WARREN...WASHINGTON...WEBSTER...WHEELER...WILCOX... WILKES...WILKINSON. && $$ SHORT TERM...BAKER LONG TERM....41 AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS LINCOLN IL
100 PM CDT WED JUL 25 2012 .DISCUSSION... ISSUED 1041 AM CDT WED JUL 25 2012 THE WARM FRONT IS CONTINUING TO LIFT NORTHEAST ACROSS CENTRAL IL WITH DRIER AIR BEHIND IT. DEWPOINTS ARE HOLDING IN THE LOWER 70S ALONG AND NORTH OF THE FRONT. OUR HIGH TEMPS WILL BE CLOSELY TIED TO HOW MUCH DRY AIR MIXES TO THE SURFACE. IF OUR DEWPOINTS DO NOT MIX DOWN INTO THE 60 TO 65 DEGREE RANGE, OUR HIGH TEMPS WILL MOST LIKELY NOT REACH 103-106 RANGE IN THOSE AREAS. WE TRIMMED HIGHS SLIGHTLY DUE TO SOME DELAY IN MIXING SO FAR, AND THE AMOUNT OF MOISTURE/DEWPOINT LEVELS IN OUR 12Z SOUNDING. STILL...WE WILL REACH VERY CLOSE TO RECORD HIGHS SOUTHWEST OF THE FRONT. CLOUD COVER LOOKS TO BE MINIMAL FOR AT LEAST THE WESTERN HALF OF THE AREA. THE CU RULE IS SHOWING CU FORMATION MORE FAVORABLE EAST OF I-57. HOWEVER...EVEN THOSE CLOUDS WILL BE A THIN LAYER AND NOT LAST VERY LONG INTO THE AFTERNOON. NO OTHER CHANGES WERE NEEDED TO THE GOING FORECAST. UPDATED INFO WILL BE AVAILABLE SHORTLY. && .AVIATION... ISSUED 1259 PM CDT WED JUL 25 2012 FAIRLY QUIET WEATHER IS IN STORE FOR TODAY... WITH VFR CONDITIONS EXPECTED THROUGH THIS TAF CYCLE. NOT MUCH IN THE WAY OF CLOUD COVER THIS AFTERNOON...WITH ONLY A FEW DIURNAL CU. WINDS WILL GENERALLY BE OUT OF THE SOUTHWEST WITH SPEEDS AROUND 10 KTS. SOME STRONGER WINDS ALOFT WILL BE MIXED DOWN TO THE SURFACE THIS AFTERNOON...SO HAVE INCLUDED GUSTS UP TO 20 KTS. AFTER SUNSET...DIURNAL CU AND GUSTS WILL DIMINISH. LLJ WILL CRANK UP OVERNIGHT SO HAVE ADDED A LINE FOR LLWS AFTER 06Z...AS LATEST MODEL SOUNDINGS SHOW WINDS AROUND 40 KTS AT 2KFT. A COLD FRONT WILL APPROACH THE AREA TOMORROW MORNING SO HAVE KEPT VCSH IN THE TAF FOR NOW AND WILL REFINE TIMING/COVERAGE WITH LATER ISSUANCES. ECT/SHIMON && .FIRE WEATHER... ISSUED 300 AM CDT WED JUL 25 2012 HAVE CONCERNS WITH RED FLAG POTENTIAL FOR THIS AFTERNOON. DEEP MIXING SHOULD ALLOW DEW POINTS TO FALL INTO THE LOWER 60S ACROSS A GOOD PORTION OF THE CWA THIS AFTERNOON. WITH THE BRUTAL TEMPERATURES EXPECTED...THIS LEVEL OF MIXING WOULD DROP HUMIDITY VALUES INTO THE 20-25 PERCENT RANGE THIS AFTERNOON. MAIN ISSUE IS THAT WINDS WILL BE A BIT BORDERLINE. SURFACE WIND GUSTS AROUND 25 MPH WILL BE POSSIBLE ACROSS PRIMARILY AREAS WEST OF I-55 BY THIS AFTERNOON...BUT 20-FOOT SUSTAINED WINDS WILL BE CLOSER TO 15 MPH... JUST SHY OF CRITERIA. WILL CONTINUE THE SPECIAL WEATHER STATEMENT TO HIGHLIGHT THE FIRE DANGER...AND CONTINUE TO MONITOR FOR ANY POTENTIAL NEED FOR A RED FLAG WARNING. GEELHART && .CLIMATE... ISSUED 300 AM CDT WED JUL 25 2012 RECORD HIGH TEMPERATURES FOR TODAY... BLOOMINGTON...... 106/1934 CHAMPAIGN........ 104/1934 CHARLESTON....... 105/1934 DECATUR.......... 104/1934 JACKSONVILLE..... 108/1934 LINCOLN.......... 105/1934 OLNEY............ 103/1940 PALESTINE........ 103/1901 PEORIA........... 104/1930 SPRINGFIELD...... 103/1936 GEELHART && .PREV DISCUSSION... ISSUED 300 AM CDT WED JUL 25 2012 LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY CURVING AROUND THE WEST AND SOUTHERN FRINGES OF THE FORECAST AREA EARLY THIS MORNING...PUSHING NORTHWARD. HAVE BEEN SEEING SOME SCATTERED THUNDERSTORMS DEVELOPING OVER MAINLY THE EASTERN HALF OF THE CWA THE LAST FEW HOURS...BUT A LARGE AREA OF CLEAR SKIES WAS JUST TO OUR WEST. TEMPERATURES NORTH OF I-74 HAVE DIPPED INTO THE LOWER 70S AS OF 2 AM...BUT STILL SEEING QUITE A FEW LOWER 80S CLOSER TO THE BOUNDARY. MAIN CONCERNS ARE IN THE SHORT TERM...NAMELY THE RECORD HEAT TODAY AND ANY POTENTIAL NEED FOR ADJUSTMENTS TO HEADLINES. ALSO HAVE CONCERNS WITH CONVECTIVE DEVELOPMENT OVER THE NEXT 24 TO 36 HOURS. SHORT TERM...TODAY THROUGH THURSDAY NIGHT... LATEST VERSIONS OF THE NAM-12 AND HRRR HAVE A FAIR HANDLE ON THE CURRENT CONVECTION...AND HAVE THE RAIN OUT OF THE AREA BY MID- MORNING. WILL MAKE A LAST-MINUTE CALL ON HOW TO HANDLE THE ACTIVITY IN THE ZONES. OTHERWISE...THE MAIN STORY WILL BE THE BRUTAL HEAT. TIME-HEIGHT HUMIDITY CROSS SECTIONS SHOWING ANY CLOUD COVER RAPIDLY MOVING EAST OF THE AREA LATE THIS MORNING AS THE FRONT LIFTS NORTH OF THE AREA. DEEP MIXING FROM AROUND 750 MB SHOULD BRING DRIER AIR DOWN FROM ABOVE..AND HELP DROP DEW POINTS INTO THE 60-65 DEGREE RANGE THIS AFTERNOON. WINDS ALSO EXPECTED TO PICK UP AND GUST TO AROUND 20-25 MPH. TEMPERATURES AGAIN EXPECTED TO SOAR INTO TRIPLE DIGIT TERRITORY...AND HAVE NOT MADE ANY CHANGES TO EARLIER HIGHS OF 103-107. MUCH OF THE CWA LIKELY TO SEE RECORD HIGHS TODAY. WITH THE DRIER AIR...HEAT INDEX VALUES SHOULD ONLY BE A FEW DEGREES ABOVE THE OBSERVED TEMPERATURES. THERE ARE SOME CONCERNS THAT THE HEAT ADVISORY WILL NEED TO BE EXTENDED IN AREAS SOUTH OF I-70 THROUGH THURSDAY. HOWEVER...THE NEED IS NOT CLEAR-CUT...DUE TO POTENTIAL FOR CLOUDS AND STORMS. UPPER RIDGE OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO FLATTEN TODAY...AS A COLD FRONT DROPS SOUTHEAST TOWARD THE AREA. PASSAGE OF THE FRONT THROUGH OUR CWA WILL LIKELY TAKE UNTIL MIDDAY OR EARLY AFTERNOON ON THURSDAY. WILL SEE SCATTERED THUNDERSTORMS WEST OF I-55 DEVELOP LATER TONIGHT AS THE FRONT APPROACHES...THEN INCREASE OVER THE CWA ON THURSDAY WITH THE HEATING AHEAD OF THE FRONT. MAIN SEVERE WEATHER THREAT TODAY WILL REMAIN TO THE NORTH...BUT SOME SEVERE STORMS ARE POSSIBLE LATE THURSDAY MORNING INTO THE AFTERNOON. WILL SEE SCATTERED STORMS LINGER INTO EVENING ACROSS THE EASTERN CWA. THE NAM MODEL DOES DEVELOP SOME ADDITIONAL SHOWERS LATE THURSDAY NIGHT WITH A SECONDARY BOUNDARY COMING THROUGH THE AREA...BUT THIS DOES NOT SEEM LIKELY AT THE MOMENT. LONG TERM...FRIDAY THROUGH TUESDAY... UPPER RIDGE TO RE-ESTABLISH ITSELF OVER THE ROCKIES THIS WEEKEND...WITH A BROAD TROUGH PUSHING THROUGH THE GREAT LAKES. THIS WILL ALLOW FOR SOME MORE REASONABLE TEMPERATURES FOR THE WEEKEND. AS THE RIDGE BEGINS TO SHIFT BACK EASTWARD AGAIN... POTENTIAL FOR MCS ACTIVITY OVER THE TOP OF THE RIDGE WILL INCREASE OVER OUR AREA. MOST LIKELY TIME FRAMES FOR THIS WILL BE FROM SUNDAY NIGHT THROUGH TUESDAY...BUT EXACT LOCATIONS STILL A BIT OF A QUESTION. AS SUCH...WILL NOT GO OVERBOARD ON THE RAIN CHANCES AT THIS TIME. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031-036>038- 040>057-061>063-066>068-071>073. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
659 AM EDT WED JUL 25 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 300 AM EDT WED JUL 25 2012 AN UPPER RIDGE ACROSS THE MISSISSIPPI VALLEY WILL BUILD ACROSS THE OHIO VALLEY AND SOUTHERN STATES LATE TODAY. THIS WILL PUSH A QUASI-STATIONARY FRONT...CURRENTLY NEAR THE OHIO RIVER...NORTHEAST INTO MICHIGAN. THIS WILL RESULT IN A TEMPORARY END TO THUNDERSTORM CHANCES AND MORE HOT AND HUMID CONDITIONS WITH AFTERNOON HIGHS AROUND 100 OR MORE AND HEAT INDICES TO NEAR 110. THEN...AN UPPER LOW...ACROSS THE CANADIAN PRAIRIES AT THIS TIME...WILL DROP SOUTHEAST BEFORE OPENING UP NEAR THE WESTERN SHORES OF LAKE SUPERIOR. THIS WILL CAUSE THE UPPER FLOW TO BUCKLE AND FORCE A COLD FRONT THROUGH CENTRAL INDIANA LATE THURSDAY INTO EARLY FRIDAY. THE RESULT WILL BE THUNDERSTORM CHANCES THURSDAY THROUGH FRIDAY ALONG WITH MORE SEASONABLE TEMPERATURES IN THE 80S IN THE WAKE OF THE FRONT FOR THE WEEKEND. FINALLY...THE COLD FRONT WILL STALL ACROSS THE SOUTH AND GRADUALLY LIFT NORTHEASTWARD AND COMBINE WITH DISTURBANCES IN THE FAST UPPER FLOW TO BRING MORE THUNDERSTORM CHANCES TO CENTRAL INDIANA SUNDAY NIGHT AND THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... ISSUED AT 300 AM EDT WED JUL 25 2012 MAIN CONCERN TODAY WILL BE THE HEAT...ALTHOUGH THUNDERSTORM CHANCES WILL ALSO BE UNDER THE MAGNIFYING GLASS. RADAR LOOP EARLY OVERNIGHT CONTINUED TO SHOW SCATTERED THUNDERSTORMS ACROSS SOUTHWESTERN PARTS OF THE FORECAST NEAR A QUASI-STATIONARY FRONT FROM AROUND SULLIVAN TO COLUMBUS AND JUST AHEAD OF AN UPPER DISTURBANCE ACROSS SOUTHERN ILLINOIS. THE LATTER FEATURE WAS JUST AHEAD OF AN UPPER RIDGE AXIS FROM CENTRAL MINNESOTA TO EASTERN TEXAS AND WESTERN LOUISIANA. THIS RIDGE WILL PROPAGATE EAST TO THE MISSISSIPPI VALLY BY LATE MORNING AND THE OHIO VALLEY TO THE GULF LATE IN THE DAY. THIS WILL RESULT IN THE SOUTH CENTRAL IINDIANA FRONT LIFTING NORTHEAST INTO SOUTHERN LOWER MICHIGAN LATE IN THE DAY. AS THE FRONT LIFTS NORTHEAST...PLENTY OF INSTABILITY IS EXPECTED TODAY WITH MIXED LAYER CAPES 2500 J/KG OR MORE POOLED ALONG THE FRONT. WITH THE RIDGE MOVING IN AND THE FRONT LIFTING THROUGH THOUGH...WILL CONFINE POPS TO THE MORNING AND EARLY AFTERNOON HOURS WITH BEST CHANCE NORTHEAST CLOSER TO THE EXPECTED MID DAY FRONTAL POSITION. SHOULD SEE A GOOD DEGREE OF SUNSHINE IN THE WARM SECTOR...AND MODEL 850 MILLIBAR TEMPERATURES FROM 24 TO 26 DEGREES AGAIN SUGGEST TEMPERATURES AROUND 100 DEGREES AND A FEW DEGREES WARMER SOUTHWEST. DEW POINTS MOSTLY IN THE UPPER 60S AND LOWER 70S AS THEY WERE YESTERDAY AFTERNOON IN THE WARM SECTOR WOULD PRODUCE HEAT INDICES NEAR 110 DEGREES AND CERTAINLY JUSTIFIES CONTINUING THE HEAT ADVISORY FOR THE SOUTHWEST AND FOR ALL COUNTIES AFTER 15Z AND THROUGH 00Z THIS EVENING. ONCE AGAIN...THE NAM MOS LOOKS FAR SUPERIOR AS THE GFS CONTINUES TO HAVE IT`S PROBLEMS WITH THESE DROUGHT CONDITIONS REGARDING TEMPERATURE OUTPUT. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... ISSUED AT 300 AM EDT WED JUL 25 2012 FOCUS TO THE SHORT TERM WILL BE WITH TIMING AND COVERAGE OF THUNDERSTORMS AS A CANADIAN PRAIRIE UPPER LOW DROPS SOUTHEAST TO NEAR LAKE SUPERIOR AS IT OPENS UP AND CONTINUES TO DROP SOUTHEAST ON FRIDAY. THE FLOW AROUND THE BASE OF THIS FEATURE WILL BE FAST AND ZONAL THURSDAY BEFORE A DISTURBANCE BUCKLES THE FLOW FRIDAY. THIS FLOW WILL PUSH A COLD FRONT ACROSS THURSDAY NIGHT AND A REINFORCING ONE ON FRIDAY. SHOULD SEE DRY WEATHER TONIGHT AND THEN DECENT THUNDERSTORM CHANCES THURSDAY AND THURSDAY EVENING WITH LINGERING CHANCES WITH THE SECOND FRONT MAINLY EAST ON FRIDAY AS DEEPER MOISTURE MOVES INTO OHIO. 90 KNOT JET 250 KNOT JET ACROSS THE GREAT LAKES...50 KNOT JET ACROSS NORTHERN INDIANA AND 25 KNOT LOW LEVEL FLOW ALONG WITH MIXED LAYER CAPES AROUND 2000 J/KG WILL HELP THINGS ALONG AND JUSTIFY SPC DAY2 SLIGHT RISK. UNIDIRECTIONAL FLOW AND FREEZING LEVELS ABOVE 15K FEET SUGGEST WIND DAMAGE WILL BE THE MAIN THREAT. FRIDAY NIGHT SHOULD BE DRY AND COOLER WITH OVERNIGHT LOWS IN THE 60S AS HIGH PRESSURE BUILDS IN FROM THE PLAINS. A BIG CHANGE IN TEMPERATURES WILL OCCUR BEHIND THE CANADIAN SYSTEM BY FRIDAY NIGHT BUT NOT BEFORE TWO MORE DAYS OF 90 PLUS DEGREES. MAY NEED TO GO WITH A HEAT ADVISORY FOR THURSDAY ACROSS OUR SOUTHWEST COUNTIES...BUT FOR NOW...THE HEAT ADVISORY ACROSS THE SOUTHWEST WILL EXPAND TO ALL COUNTIES LATER TODAY...AND ANY OTHER WORDING MAY CAUSE CONFUSION. WILL CONTINUE TO FAVOR THE HOTTER AND MORE IN TUNED NAM MOS THROUGH FRIDAY. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... ISSUED AT 253 AM EDT WED JUL 25 2012 INITIALIZATION HAD RELATIVELY FEW ISSUES THIS MORNING. LONG TERM WILL BEGIN WITH A DRY PERIOD AS HIGH PRESSURE TRAVERSES THE REGION. MODEL DISCREPANCIES EXIST LATER IN THE PERIOD AS SUBTLE DISTURBANCES AND A POSSIBLE BOUNDARY MAY PROVIDE OPPORTUNITIES FOR THUNDERSTORMS...BUT FELT POPS WERE BEST CAPPED AT 20 TO 30 PERCENT IN LIGHT OF THIS SIGNIFICANT UNCERTAINTY. TWEAKED MAX TEMPS UPWARD A BIT MOST PERIODS TO ACCOUNT FOR CONTINUING DROUGHT AND INFLUENCE OF COOL BIASED GFS. && .AVIATION /DISCUSSION FOR THE 25/12Z TAFS/... ISSUED AT 659 AM EDT WED JUL 25 2012 VFR THROUGH THE PERIOD OUTSIDE OF ANY POSSIBLE THUNDERSTORMS. WARM FRONT THAT HAD BEEN BRIEFLY STALLED TO OUR SOUTHWEST WILL LIFT BACK NORTHEAST TODAY...WITH THE POSSIBILITY OF THUNDERSTORMS MAINLY ALONG AND NEAR THE BOUNDARY. HRRR AND SREF PROBABILITIES INDICATE POTENTIAL FOR THUNDERSTORMS MOST OF THE DAY...BUT WITH LACK OF ORGANIZATION CANNOT GO WITH MORE THAN A VICINITY MENTION THROUGH THE PEAK HEATING HOURS. WILL HAVE AN INITIAL VICINITY MENTION LAF/HUF...NEARER WHERE ISOLATED SHOWERS HAVE BEEN POPPING UP THROUGH THE MORNING. WINDS WILL BECOME SOUTHWESTERLY BEHIND THE FRONT...IN THE 15KT RANGE. CANNOT RULE OUT A FEW GUSTS TO 20KT RANGE...BUT THESE WOULD BE EXTREMELY SPORADIC. && .IND WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR INZ021-028>031-035>049-054>057-063>065-071-072. HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ051>053-060>062- 067>070. && $$ SYNOPSIS...MK NEAR TERM...MK SHORT TERM...MK LONG TERM....NIELD AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS DES MOINES IA
337 PM CDT WED JUL 25 2012 .SHORT TERM /TONIGHT/... MAIN FORECAST CONCERN IS WITH TIMING OF COLD FRONT AND CONVECTION POTENTIAL THIS EVENING INTO THE OVERNIGHT HOURS. NAM/RAP SEEM TO HAVE A DECENT HANDLE ON INITIATION OF CONVECTION AND LEANED TOWARD TIMING OF FRONT/POPS. THE 16Z HRRR HAS SOME ISOLATED CONVECTION DEVELOPING B/T 22-00Z BUT THINKING CAP IS STILL TOO STRONG FOR MUCH CONVECTION TO GET GOING UNTIL AFTER 00Z. REALLY CUT BACK ON POPS UNTIL AFTER 00Z OVER THE CENTRAL AND SOUTHEAST CWA. THE 12Z 4.0KM WRF MODEL RUNS FROM NSSL AND NCEP BOTH HAVE VERY SPOTTY PRECIP THROUGH TONIGHT...AND SORT OF LIGHTS UP THE FRONT SOUTH OF INTERSTATE 80 AFTER 02Z THURSDAY. HAVE LOW CONFIDENCE WITH ANY WIDESPREAD SIGNIFICANT CONVECTION TONIGHT. MODELS FORECASTING PW VALUES NEAR 2 INCHES GENERALLY ALONG THE FRONT...AND 1-1.5 INCHES BEHIND IT. HOWEVER...WITH SUCH SPOTTY CONVECTION AND LOWERED QPF AMOUNTS TO LESS THAN A HALF INCH THROUGHOUT THE FORECAST AREA...ESPECIALLY WITH SUCH HIGH BASED CONVECTION. PLENTY OF SURFACE BASED INSTABILITY...BUT LITTLE IF ANY EFFECTIVE SHEAR AVAILABLE...AS WELL AS FORCING OTHER THAN THE FRONTAL BOUNDARY TONIGHT. THINKING MAIN SEVERE THREAT WILL BE WINDS WITH THE DRY AIRMASS PRESENT. .LONG TERM /THURSDAY THROUGH WEDNESDAY/... LARGE SCALE MAINLY POST FRONTAL FORCING SHOULD BE JUST EXITING FORECAST AREA BY THE START OF THE PERIOD SO ANY LINGERING PRECIP...IF ANY...SHOULD BE MOVING INTO MO AND IL. FORECAST DRY AFTER 15Z. PREVIOUS FORECAST HAD LOW POPS BRUSHING NERN IA BY LATE AFTERNOON BUT CANNOT REALLY FIND ANY SUPPORT FOR THIS WITH LIMITED FORCING AND INSUFFICIENT MOISTURE...AND EVEN THAT LOOKS TO BE POST 00Z. UPSTREAM NRN PLAINS AIRMASS WILL GRADUALLY PASS THROUGH IA DURING THE DAY BUT DEEP NW FLOW AND MIXING WILL STILL ALLOW CENTRAL/SRN HIGHS TO REACH LOW/MID 90S BY AFTERNOON. DO NOT ANTICIPATED ENOUGH PRECIP TONIGHT TO AFFECT THAT. BLEND OF SREF/NAM SOUNDINGS SEEMS REASONABLE. NRN PLAINS SURFACE RIDGE WILL RETURN IA TEMPS TO NORMAL FOR FRI WITH CONTINUED DRY WEATHER AS GREAT LAKES SHORT WAVE DEPARTS. THIS WILL BE FOLLOWED BY AN EXTENDED PERIOD OF ROCKIES AND HIGH PLAINS RIDGING...RIGHT INTO WED AND BEYOND...LEAVING IA WITH WARM BUT NOT EXTREME TEMPS AND LOW END PRECIP POTENTIAL. CHANCES INCREASE SOMEWHAT THIS WEEKEND AS SHORT WAVE TOPS THE RIDGE INCREASING FORCING...ESPECIALLY THERMODYNAMIC...BY SAT. THIS WEAK FORCING LINGERS INTO SUN...AND POSSIBLY EARLY MON LEADING TO SEVERAL DAYS WORTH OF CHANCE POPS. MODELS CONTINUE TO DABBLE IN WEAK QPF EVENTS AFTER THIS TIME...BUT THERE IS REALLY NO CONSISTENT FORCING FEATURE TO LATCH ONTO SO HAVE LEFT MON NIGHT-WED DRY AT THIS POINT. REGARDING TEMPS..ONLY REAL CONCERN IS LOW CONFIDENCE FORECAST SATURDAY. QUESTIONS ON HOW MUCH WE WILL MIX IN NEW REGIME WITH LIGHT WINDS. HAVE PRETTY MUCH MIXED THINGS OUT TO 900-850MB OR MORE...MIXING SEASONALLY...BUT FEEL NAM IS UNDERDONE WHICH SEEMS TO BE THE CASE AT TIMES IN WEAK FLOW. && .AVIATION...25/18Z STRONG SOUTHWEST FLOW AND DEEP MIXING WILL CONTINUE AHEAD OF THE COLD FRONT THROUGH THE LATE AFTERNOON/EARLY EVENING. HAVE LOW CONFIDENCE WITH TIMING AND LOCATION OF CONVECTION WITH THE FRONT MOVING THROUGH. LATEST 4.0KM WRF-NMM SUGGEST SPOTTY CONVECTION ALONG AND BEHIND THE FRONT...SO JUST HAVE MENTION OF VCTS ATTM. OTHERWISE...WINDS BEGIN TO MIX AGAIN OUT OF THE WEST NORTHWEST TOMORROW LATE IN THE MORNING. && .DMX WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 7 PM CDT ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE- CRAWFORD-DALLAS-DAVIS-DECATUR-GREENE-GUTHRIE-HAMILTON-JASPER-LUCAS- MADISON-MAHASKA-MARION-MONROE-POLK-RINGGOLD-SAC-STORY-TAYLOR-UNION- WAPELLO-WARREN-WAYNE-WEBSTER HEAT ADVISORY UNTIL 7 PM CDT BLACK HAWK-BREMER-BUTLER-FRANKLIN-GRUNDY-HARDIN-HUMBOLDT-MARSHALL- POCAHONTAS-POWESHIEK-TAMA-WRIGHT && $$ SHORT TERM/AVIATION...PODRAZIK LONG TERM...SMALL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1233 PM CDT WED JUL 25 2012 .AVIATION... VFR WX WILL BE SEEN THROUGH 00Z/26. HOWEVER...DENSITY ALTITUDES WILL BE 3-4 KFT THROUGH AT LEAST 01Z/26. A COLD FRONT WILL BEGIN TO SLOWLY MOVE THROUGH EASTERN IOWA AND NORTHERN ILLINOIS STARTING AROUND 00Z/26. KCID/KDBQ HAVE THE BEST CHANCE AT SEEING A TSRA WITH MVFR CONDITIONS. THE FRONT IS FORECAST TO WEAKEN AFT SUNSET SO THE POTENTIAL FOR TSRA AT KMLI/KBRL ARE MORE UNCERTAIN. VFR CONDITIONS ARE EXPECTED TO CONTINUE AFT 00Z/26 WITH THE POTENTIAL FOR SHRA WITH POSSIBLY SOME TSRA. ...08.. && .PREV DISCUSSION... /ISSUED 1101 AM CDT WED JUL 25 2012/ UPDATE... DATA THROUGH 15Z INDICATES THAT THE INVERSION IS ESSENTIALLY GONE. WINDS ARE STARTING TO INCREASE PER SFC OBS. INTERESTINGLY...DEW POINTS HAVE INCREASED SINCE SUNRISE. THIS INCREASE IS PARTIALLY DUE TO THE CORN STARTING TO ACTIVELY EVAPOTRANSPIRATE BUT IT IS ALSO A RESULT OF POOLING ALONG A FRONT/BOUNDARY MOVING THROUGH THE CWFA. RAP TRENDS INDICATE THIS FRONT/BOUNDARY WILL EXIT THE CWFA IN THE NEXT FEW HOURS ALLOWING TEMPERATURES ACROSS THE NORTH TO QUICKLY WARM. AS THE FRONT/BOUNDARY LEAVES THE AREA...DEW POINTS SHOULD SLOWLY DROP AS DEEPER MIXING OF THE ATMOSPHERE OCCURS. THE HIGH THIN CI/CS IS A CONCERN ACROSS THE NORTHERN CWFA AS IT COULD SUPPRESS TEMPERATURES TODAY. ATTENTION THEN TURNS TO PRECIP CHANCES LATER TODAY. RAP TRENDS GENERALLY HAVE CONVECTIVE TEMPERATURES AT OR ABOVE 103. AS SUCH CONVECTION SHOULD BE DELAYED UNTIL VERY LATE IN THE AFTERNOON. REAL AND MODEL DATA CONTINUES TO SUPPORT AN ANAFRONT WITH PRECIP ALONG/BEHIND THE FRONT. IF RAP TRENDS FROM THE LIFT TOOL AND GENERAL ISENTROPICS ON THE 335K THETA SFC CONTINUE... PRECIPITATION MAY NOT BEGIN IN THE HWY 20 CORRIDOR WEST OF DUBUQUE UNTIL ROUGHLY 6 OR 7 PM. AS SUCH THE FCST HAS PUSHED BACK THE START OF ANY CONVECTION UNTIL 5 PM. THESE TRENDS WILL NEED TO BE MONITORED THROUGH THE AFTERNOON. THE HEAT HEADLINES WILL CONTINUE. ANY REFINEMENTS TO THE AREAL AND TEMPORAL COVERAGE WILL BE ADDRESSED THIS AFTERNOON. MODEL TRENDS CONTINUE TO SHOW THE OVERALL FORCING BECOMING WEAKER AFTER SUNSET. SUCH A TREND IS DISTURBING AS IT WOULD SUGGEST NOT MUCH IN THE WAY OF RAIN TONIGHT. ..08.. CLIMATE... RECORD HIGHS FOR JULY 25... BURLINGTON.....107 IN 1936 CEDAR RAPIDS...105 IN 1940 DUBUQUE........102 IN 1940 MOLINE.........105 IN 1940 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON-BUCHANAN- CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA- JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA- MUSCATINE-SCOTT-VAN BUREN-WASHINGTON. IL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BUREAU-CARROLL- HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER- PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE. MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLARK-SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1101 AM CDT WED JUL 25 2012 .UPDATE... DATA THROUGH 15Z INDICATES THAT THE INVERSION IS ESSENTIALLY GONE. WINDS ARE STARTING TO INCREASE PER SFC OBS. INTERESTINGLY...DEW POINTS HAVE INCREASED SINCE SUNRISE. THIS INCREASE IS PARTIALLY DUE TO THE CORN STARTING TO ACTIVELY EVAPOTRANSPIRATE BUT IT IS ALSO A RESULT OF POOLING ALONG A FRONT/BOUNDARY MOVING THROUGH THE CWFA. RAP TRENDS INDICATE THIS FRONT/BOUNDARY WILL EXIT THE CWFA IN THE NEXT FEW HOURS ALLOWING TEMPERATURES ACROSS THE NORTH TO QUICKLY WARM. AS THE FRONT/BOUNDARY LEAVES THE AREA...DEW POINTS SHOULD SLOWLY DROP AS DEEPER MIXING OF THE ATMOSPHERE OCCURS. THE HIGH THIN CI/CS IS A CONCERN ACROSS THE NORTHERN CWFA AS IT COULD SUPPRESS TEMPERATURES TODAY. ATTENTION THEN TURNS TO PRECIP CHANCES LATER TODAY. RAP TRENDS GENERALLY HAVE CONVECTIVE TEMPERATURES AT OR ABOVE 103. AS SUCH CONVECTION SHOULD BE DELAYED UNTIL VERY LATE IN THE AFTERNOON. REAL AND MODEL DATA CONTINUES TO SUPPORT AN ANAFRONT WITH PRECIP ALONG/BEHIND THE FRONT. IF RAP TRENDS FROM THE LIFT TOOL AND GENERAL ISENTROPICS ON THE 335K THETA SFC CONTINUE... PRECIPITATION MAY NOT BEGIN IN THE HWY 20 CORRIDOR WEST OF DUBUQUE UNTIL ROUGHLY 6 OR 7 PM. AS SUCH THE FCST HAS PUSHED BACK THE START OF ANY CONVECTION UNTIL 5 PM. THESE TRENDS WILL NEED TO BE MONITORED THROUGH THE AFTERNOON. THE HEAT HEADLINES WILL CONTINUE. ANY REFINEMENTS TO THE AREAL AND TEMPORAL COVERAGE WILL BE ADDRESSED THIS AFTERNOON. MODEL TRENDS CONTINUE TO SHOW THE OVERALL FORCING BECOMING WEAKER AFTER SUNSET. SUCH A TREND IS DISTURBING AS IT WOULD SUGGEST NOT MUCH IN THE WAY OF RAIN TONIGHT. ..08.. && .AVIATION... VFR WX WILL BE SEEN THROUGH 00Z/26. DENSITY ALTITUDES HAVE INCREASED TO 3 KFT AND WILL BE 3-4 KFT THROUGH AT LEAST 00Z/26. AFT 00Z/26 A COLD FRONT WILL SLOWLY MOVE THROUGH THE AREA BRINGING A THREAT OF TSRA. THERE IS A POTENTIAL FOR MVFR CONDITIONS IF A TSRA AFFECTS A TAF SITE. ..08.. && .CLIMATE... RECORD HIGHS FOR JULY 25... BURLINGTON.....107 IN 1936 CEDAR RAPIDS...105 IN 1940 DUBUQUE........102 IN 1940 MOLINE.........105 IN 1940 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON-BUCHANAN- CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-JOHNSON-JONES- LINN-MUSCATINE-SCOTT. HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR DES MOINES-HENRY IA-JEFFERSON-KEOKUK-LEE-LOUISA-VAN BUREN-WASHINGTON. IL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BUREAU-CARROLL- HENRY IL-JO DAVIESS-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON- WHITESIDE. HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR HANCOCK-HENDERSON- MCDONOUGH-WARREN. MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLARK-SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
247 PM MDT WED JUL 25 2012 .SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT) ISSUED AT 1241 PM MDT WED JUL 25 2012 LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE TROUGH AXIS CURRENTLY EXTENDING ACROSS NEBRASKA PANHANDLE SOUTH ALONG KS/CO STATE LINE...AND THEN ACROSS OK/TX PANHANDLE. WV IMAGERY SHOWS PLUME OF MID LEVEL MOISTURE EXTENDING NORTH ON LEE SIDE OF ROCKIES ALONG WESTERN EDGE OF TROUGH AXIS. ANOTHER SHORTWAVE TROUGH IS CURRENTLY OVER CENTRAL WY AND SHOULD MOVE EAST INTO NEBRASKA BY THIS EVENING. AT THE SURFACE THE COLD FRONT HAS STALLED JUST SOUTHEAST OF OUR CWA. CLOUD COVER AND CONVECTION HAVE BEEN SLOW TO DEVELOP MUCH FURTHER SOUTH THAN THE EXTREME NW PART OF CWA. AS THE SHORTWAVE OVER CENTRAL WY MOVES EAST GUIDANCE CONTINUES TO SHOW LARGE SCALE ASCENT INCREASING ACROSS THE EASTERN HALF OF THE CWA IN PROXIMITY OF FRONT. AT THIS TIME LATEST HRRR AND RUC WOULD SUPPORT SCATTERED THUNDERSTORMS FORMING GENERALLY EAST OF GOODLAND AND THEN INCREASING IN COVERAGE THROUGH 00Z AS THEY MOVE EASTWARD...QUICKLY ENDING OVER OUR CWA THIS EVENING. NAM CONTINUES TO SHOW ISOLATED ACTIVITY FURTHER WEST ASSOCIATED WITH ELEVATED CAPE AND H7 FRONTOGENESIS THROUGH THE OVERNIGHT PERIOD. CONFIDENCE IS STILL TOO LOW TO INCLUDE ANY THUNDERSTORMS BEYOND THIS EVENING WITH LARGE SCALE SUBSIDENCE AND SURFACE HIGH PRESSURE QUICKLY BUILDING OVER THE CWA. I LEFT PATCHY FOG MENTION IN FORECAST OVER EASTERN LOCATIONS...WITH CLAM WINDS AND STABLE AIRMASS SUPPORTING RADIATIVE FOG DEVELOPMENT. GUIDANCE REALLY HAS NOT PICKED UP ON THIS YET...SO I HAVE LEFT FOG COVERAGE LIMITED TO PATCHY. .LONG TERM...(THURSDAY THROUGH WEDNESDAY) ISSUED AT 246 PM MDT WED JUL 25 2012 HIGH PRESSURE MOVES INTO THE PLAINS STATES AT THE SURFACE THURSDAY AND FRIDAY AS THE UPPER RIDGE AMPLIFIES OVER THE INTERMOUNTAIN WEST AND MOVES EAST OVER THE ROCKIES. PRECIPITATION CHANCES ARE MINIMAL ON THURSDAY AND THURSDAY NIGHT AS A RESULT. BY FRIDAY EVENING THE SURFACE HIGH MOVES FAR ENOUGH TO THE EAST WITH A LEE TROUGH DEEPENING IN THE VICINITY OF THE FAR EASTERN COLORADO BORDER TO FORM A CONVERGENCE AREA OVER THE WESTERN PORTION OF THE FORECAST AREA AS A SHORT WAVE TROUGH IN THE UPPER LEVEL FLOW MOVES OVER THROUGH THE TOP OF THE RIDGE AND CLIPS THE NORTHERN SECTIONS OF THE FORECAST AREA FRIDAY NIGHT. THIS SETUP WILL BRING A BETTER CHANCE OF THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. SEVERAL ADDITIONAL SHORT WAVE TROUGHS MAKE THEIR WAY AROUND THE UPPER RIDGE AND CLIP THE FORECAST AREA FROM SATURDAY THROUGH TUESDAY. WITH A SURFACE TROUGH ALSO REMAINING OVER MAINLY THE WESTERN PORTION OF THE FORECAST AREA DURING THIS TIME...THEREFORE EXPECT TEMPERATURES TO REMAIN VERY WARM WITH ADDITIONAL DIURNALLY DRIVEN ISOLATED TO SCATTERED THUNDERSTORMS MAINLY OVER THE WESTERN PORTIONS OF THE FORECAST AREA. BY THE MIDDLE OF NEXT WEEK...CURRENT INDICATIONS ARE THAT THE UPPER RIDGE WILL AMPLIFY FURTHER AND MOVE MORE OVER THE PLAINS STATES...SENDING THE SHORT WAVE IMPULSES FURTHER NORTH THROUGH THE NORTHERN PLAINS AND POSSIBLY DECREASING THE POSSIBILITY OF PRECIPITATION ACROSS THE CENTRAL HIGH PLAINS REGION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1101 AM MDT WED JUL 25 2012 SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE FROM THE SOUTHWEST TO THE NORTHEAST EARLY IN THE TAF PERIOD. THUNDERSTORMS WILL INCREASE IN COVERAGE AS UPPER LEVEL DISTURBANCE SHIFTS SOUTH AND EAST OVER THE AREA...WITH THUNDERSTORM ACTIVITY POSSIBLY IMPACTING TERMINALS LATE THIS AFTERNOON AND EARLY THIS EVENING. GUSTY NORTH WINDS WILL CONTINUE THROUGH THE AFTERNOON AND THEN DECREASE BY THIS EVENING AS FRONTAL ZONE SHIFTS SOUTHEAST. MVFR CONDITIONS IS POSSIBLE LATE TONIGHT/EARLY THURSDAY MORNING AT KMCK AS A RESULT OF PATCHY FOG DEVELOPING UNDER SURFACE HIGH PRESSURE. CONFIDENCE WAS TOO LOW TO PREVAIL THESE CONDITIONS AT THIS TAF ISSUANCE...SO LEFT VIS/CIGS VFR FOR NOW. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...LOCKHART AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1241 PM MDT WED JUL 25 2012 .SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT) ISSUED AT 1241 PM MDT WED JUL 25 2012 LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE TROUGH AXIS CURRENTLY EXTENDING ACROSS NEBRASKA PANHANDLE SOUTH ALONG KS/CO STATE LINE...AND THEN ACROSS OK/TX PANHANDLE. WV IMAGERY SHOWS PLUME OF MID LEVEL MOISTURE EXTENDING NORTH ON LEE SIDE OF ROCKIES ALONG WESTERN EDGE OF TROUGH AXIS. ANOTHER SHORTWAVE TROUGH IS CURRENTLY OVER CENTRAL WY AND SHOULD MOVE EAST INTO NEBRASKA BY THIS EVENING. AT THE SURFACE THE COLD FRONT HAS STALLED JUST SOUTHEAST OF OUR CWA. CLOUD COVER AND CONVECTION HAVE BEEN SLOW TO DEVELOP MUCH FURTHER SOUTH THAN THE EXTREME NW PART OF CWA. AS THE SHORTWAVE OVER CENTRAL WY MOVES EAST GUIDANCE CONTINUES TO SHOW LARGE SCALE ASCENT INCREASING ACROSS THE EASTERN HALF OF THE CWA IN PROXIMITY OF FRONT. AT THIS TIME LATEST HRRR AND RUC WOULD SUPPORT SCATTERED THUNDERSTORMS FORMING GENERALLY EAST OF GOODLAND AND THEN INCREASING IN COVERAGE THROUGH 00Z AS THEY MOVE EASTWARD...QUICKLY ENDING OVER OUR CWA THIS EVENING. NAM CONTINUES TO SHOW ISOLATED ACTIVITY FURTHER WEST ASSOCIATED WITH ELEVATED CAPE AND H7 FRONTOGENISIS THROUGH THE OVERNIGHT PERIOD. CONFIDENCE IS STILL TOO LOW TO INCLUDE ANY THUNDERSTORMS BEYOND THIS EVENING WITH LARGE SCALE SUBSIDENCE AND SURFACE HIGH PRESSURE QUICKLY BUILDING OVER THE CWA. I LEFT PATCHY FOG MENTION IN FORECAST OVER EASTERN LOCATIONS...WITH CLAM WINDS AND STABLE AIRMASS SUPPORTING RADIATIVE FOG DEVELOPMENT. GUIDANCE REALLY HASNT PICKED UP ON THIS YET...SO I HAVE LEFT FOG COVERAGE LIMITED TO PATCHY. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 258 AM MDT WED JUL 25 2012 THURSDAY NIGHT-FRIDAY NIGHT...DESPITE SLOWLY AMPLIFYING RIDGE ACROSS THE AREA...THERE WILL BE PERIODS OF LARGE SCALE FORCING FOR ASCENT THROUGH THE PERIOD AS RIDGE AXIS REMAINS TO THE WEST OF THE AREA AND A FEW SMALL SHORT WAVE TROUGHS MOVE OVER THE TOP OF THE RIDGE AND IMPACT THE AREA. SOME DIFFERENCES EXIST WITH RESPECT TO HOW STRONG UPCOMING RIDGE WILL BE WHICH WILL STRONGLY IMPACT HOW MUCH INFLUENCE ANY OF THESE SMALL SCALE TROUGHS WILL HAVE. WHILE NAM AND SREF QUITE AGGRESSIVE DEVELOPING CONVECTION ACROSS NORTHERN CWA...GFS AND GEFS MUCH DRIER. FOR NOW...THINK GEFS SOLUTION OF 15-20 POPS REFLECTS THE EXPECTED PATTERN PRETTY WELL. THE NEXT UPPER LEVEL RIDGE WILL BUILD OVER THE INTERMOUNTAIN WEST AND OVER THE ROCKIES BY THIS WEEKEND. A FEW SHORTWAVE TROUGHS WILL MOVE THROUGH THE FLOW DURING THE PERIOD AND WITH SURFACE TROUGH DEEPENING ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED AFTERNOON THUNDERSTORMS MOST DAYS. BY EARLY NEXT WEEK...THE RIDGE WILL MOVE EASTWARD INTO THE PLAINS WITH THE MAIN CENTER OF THE HIGH POSITIONED ACROSS THE SOUTHERN PLAINS REGION MONDAY BEFORE RETROGRADING BACK INTO THE SOUTHERN ROCKY MOUNTAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1101 AM MDT WED JUL 25 2012 SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE FROM THE SOUTHWEST TO THE NORTHEAST EARLY IN THE TAF PERIOD. THUNDERSTORMS WILL INCREASE IN COVERAGE AS UPPER LEVEL DISTURBANCE SHIFTS SOUTH AND EAST OVER THE AREA...WITH THUNDERSTORM ACTIVITY POSSIBLY IMPACTING TERMINALS LATE THIS AFTERNOON AND EARLY THIS EVENING. GUSTY NORTH WINDS WILL CONTINUE THROUGH THE AFTERNOON AND THEN DECREASE BY THIS EVENING AS FRONTAL ZONE SHIFTS SOUTHEAST. MVFR CONDITIONS IS POSSIBLE LATE TONIGHT/EARLY THURSDAY MORNING AT KMCK AS A RESULT OF PATCHY FOG DEVELOPING UNDER SURFACE HIGH PRESSURE. CONFIDENCE WAS TOO LOW TO PREVAIL THESE CONDITIONS AT THIS TAF ISSUANCE...SO LEFT VIS/CIGS VFR FOR NOW. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JRM/PMM AVIATION...DR
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1209 PM CDT WED JUL 25 2012 ...UPDATED FOR AVIATION... .SYNOPSIS... ISSUED AT 418 AM CDT WED JUL 25 2012 AN INTENSE UPPER LOW OVER THE SOUTHERN CANADIAN PRAIRIES CONTINUED TO MOVE SLOWLY EAST DURING THE OVERNIGHT HOURS. THERE WERE TWO LOWS EVIDENT AT 850MB IN THE 25.00Z ANALYSIS. THE NORTHERN LOW WAS WELL INTO CANADA NEAR SASKATOON, SASKATCHEWAN. FARTHER SOUTH IN THE CONUS...A LOW WAS CENTERED EAST OF THE BLACK HILLS OF SOUTH DAKOTA. A FAIRLY INTENSE TEMPERATURE GRADIENT WAS NOTED ACROSS SOUTH DAKOTA WITH +20C AT BISMARCK, ND AND +31C NOSING INTO SOUTH CENTRAL SD PER THE RAP ANALYSIS. SEVERAL CLUSTERS OF THUNDERSTORMS DEVELOPED ACROSS SOUTH DAKOTA ALONG THIS BAROCLINIC ZONE, WITH A LARGE MCS ROLLING ACROSS NORTHERN MINNESOTA AS OF 08Z. ELSEWHERE...A SUBTLE BUT IMPORTANT SHORTWAVE TROUGH COULD BE PICKED OUT IN THE RAP ANALYSIS AND WATER VAPOR IMAGERY MOVING EAST THROUGH UTAH AND SOUTHWESTERN WYOMING...MOVING INTO WESTERN/NORTHWESTERN COLORADO. A SURFACE COLD FRONT AS OF 08Z EXTENDED FROM NORTH CENTRAL NEBRASKA TO NORTHEASTERN COLORADO. SURFACE WINDS BEHIND THE FRONT IN EASTERN COLORADO AND THE NEBRASKA PANHANDLE WERE NORTHWEST 20 TO 25 KNOTS WITH SOME GUSTS IN SOME PLACES EXCEEDING 30 KNOTS. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 418 AM CDT WED JUL 25 2012 THE MAIN CHALLENGE IN THE FORECAST PERTAINS TO THUNDERSTORM CHANCES, STRENGTH, AND LOCATION OF THOSE BEST CHANCES LATER ON THIS AFTERNOON AND TONIGHT AS THE COLD FRONT REACHES SOUTHWEST KANSAS. 850MB TEMPS AHEAD OF THE FRONT UP TO +31C SUGGEST ANOTHER DAY OF HIGHS IN THE 103 TO 106F RANGE WITH THE NORTHERN FORECAST AREA SEEING THE HOTTEST TEMPERATURES AGAIN...MUCH LIKE THE PAST FEW DAYS. IF THE STORMS HOLD OFF LONG ENOUGH...HAYS COULD REACH 108F AGAIN LIKE YESTERDAY. INITIAL THUNDERSTORMS SHOULD DEVELOP AS SURFACE TEMPERATURES APPROACH CONVECTIVE TEMPERATURE ALONG AN AXIS FROM ROUGHLY ELKHART TO SYRACUSE TO WAKEENEY-GOVE AREAS. OTHER STORMS MAY FORM FARTHER EAST TIED TO A WEAK MID LEVEL VORTICITY ANOMALY THAT WILL MOVE SLOWLY EAST ACROSS SOUTHWEST KANSAS DURING THE AFTERNOON. THESE STORMS SHOULD BE ALL THAT STRONG SINCE LOW LEVEL CONVERGENCE WILL BE ESSENTIALLY NON-EXISTENT (REMAINING FARTHER NORTH). THE MOST ORGANIZED THUNDERSTORMS WILL DEVELOP IN THE 22-00Z TIME FRAME FROM ROUGHLY LAKIN TO SCOTT CITY TO WAKEENEY. THESE STORMS WILL ADVANCE SLOWLY SOUTHEAST THROUGH THE EVENING HOURS WITH SUBSEQUENT DEVELOPMENT OF STORMS FORMING ON VARIOUS COLD POOL INTERACTIONS WHICH ARE IMPOSSIBLE TO PREDICT. IT IS UNCLEAR WHETHER A SMALL MCS MAY DEVELOP AND THRIVE PAST THE ~04Z TIME FRAME...AS LOW LEVEL MOISTURE, WHILE ADEQUATE IN THE UPPER 50S TO LOWER 60S...WILL NOT BE NEAR WHAT THE GFS MODEL IS SUGGESTING (A CHRONIC PROBLEM WITH THIS MODEL ALL SEASON). THE SHORTWAVE TROUGH MENTIONED IN THE SYNOPSIS SECTION ENTERING COLORADO WILL AID IN SOME INCREASED DEEP UPWARD VERTICAL MOTION LATE TONIGHT...BUT BY THE TIME THAT REACHES WESTERN KANSAS...MUCH OF THE CONVECTIVE ACTIVITY WILL LIKELY HAVE SHIFTED EAST INTO CENTRAL KANSAS. AS FAR AS THE POP FORECAST GOES...WILL BE INCREASING THE POPS TO 50-60 PERCENT NORTH OF A GARDEN CITY TO LARNED LINE TO INTERSTATE 70 CORRIDOR. AS FAR AS THE SEVERE WEATHER POTENTIAL GOES...THERE IS DEFINITELY A CHANCE AT AT LEAST SOME ISOLATED SEVERE WIND REPORTS GIVEN THE SIGNIFICANT TEMPERATURE-DEWPOINT SPREADS. STRONG UPDRAFTS ARE QUITE LIKELY GIVEN THE STRONG LOW LEVEL CONVERGENCE WITH THE SLOW MOVING FRONT. THIS WILL LEAD TO INTENSE DOWNDRAFTS AND EVEN A FEW SEVERE MICROBURSTS. THE HAIL THREAT IS RATHER LOW CONSIDERING THE POOR VERTICAL WIND SHEAR AND OVERALL WARM MID LEVEL TEMPERATURES AS WELL AS HIGH MELTING AND -20C LEVELS. WILL BE DECREASING POPS ACROSS MUCH OF THE FORECAST AREA DURING THE 06-12Z TIME FRAME WITH COLD ADVECTION TAKING OVER IN THE LOW LEVELS AS THE SYNOPTIC FRONT CONTINUES SOUTHEAST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 234 AM CDT WED JUL 25 2012 MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE DEVELOPING ACROSS THE FAR INTERMOUNTAIN WEST TODAY AND DRIFTING SLOWLY EAST ACROSS THE ROCKIES TO BEGIN THE PERIOD THURSDAY. IT WILL MOVE FURTHER INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND QUICKLY BRINGING A GENERALLY DRIER WEATHER PATTERN BACK TO WESTERN KANSAS DURING MUCH OF THE PERIOD. AIDING THIS DRIER PATTERN WILL BE A FAIRLY WEAK FLOW ALOFT ASSOCIATED WITH THE UPPER LEVEL RIDGING. TEMPERATURES ARE EXPECTED TO BE MORE SEASONAL THURSDAY IN WAKE OF A COLD FRONTAL PASSAGE LATE WEDNESDAY. A NORTH TO NORTHEAST LOW LEVEL FLOW WILL PREVAIL ACROSS WESTERN KANSAS THURSDAY HELPING TO LOWER H85 TEMPERATURES EVER SO SLIGHTLY WITH VALUES GENERALLY RANGING FROM THE MID 20S(C) ACROSS CENTRAL KANSAS TO THE UPPER 20S(C) IN EXTREME SOUTHWEST KANSAS. LOOK FOR HIGHS ONLY UP INTO THE 90S(F) THURSDAY AFTERNOON. A GRADUAL WARMING TREND IS STILL EXPECTED INTO THE WEEKEND AS THE AFOREMENTIONED UPPER LEVEL RIDGING APPROACHES FROM THE INTERMOUNTAIN WEST BY THURSDAY AND BEGINS TO PUSH EAST INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND. SHOULD SEE HIGHS CLIMBING UP NEAR TO JUST ABOVE 100F BY THE CLOSE OF THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1155 AM CDT WED JUL 25 2012 A COLD FRONT WILL MOVE ACROSS THE TAF SITES BETWEEN 01-03Z THIS EVENING WITH A CHANCE FOR THUNDERSTORMS. THUNDERSTORM CHANCES DIMINISH AFTER 06-08Z TONIGHT AS THE COLD FRONT CONTINUES SOUTHEASTWARD. SOME STORMS COULD PRODUCE WIND GUSTS TO 40 KT AND SMALL HAIL TO DIME SIZE. SOUTHERLY WINDS OF 15-22 KT WILL SHIFT TO NORTH TO NORTHEASTERLY 10-22 KT. EXPECT VFR CONDITIONS. && .PRELIMINARY POINT TEMPS/POPS... DDC 104 69 96 67 / 30 40 10 0 GCK 103 67 95 66 / 40 50 10 0 EHA 102 67 93 67 / 30 30 10 0 LBL 104 68 95 67 / 30 30 10 0 HYS 106 68 95 67 / 40 60 10 0 P28 103 74 98 71 / 20 40 20 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...JJOHNSON AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1101 AM MDT WED JUL 25 2012 .UPDATE... ISSUED AT 457 AM MDT WED JUL 25 2012 ELEVATED THUNDERSTORMS HAVE DEVELOPED FARTHER TO THE EAST THAN PREVIOUSLY EXPECTED...BEING DRIVEN BY ELEVATED FRONTAL ZONE AROUND H8 AND POCKET OF WEAKLY CAPPED INSTABILITY IN BTWN H75 AND H65. WHILE PRECIP COVERAGE HAS BEEN SPOTTY...MCK MEASURED A QUICK 0.2 OF RAIN IN ABOUT 15 MINUTES AS STORM PASSED. RAP INDICATES AREA OF ELEVATED INSTABILITY SHIFTS TO THE NORTH AND DIMINISHES DURING THE MORNING HOURS...BUT THINK A STORM OR TWO MAY CONTINUE TO DEVELOP ALONG ELEVATED FRONT THIS MORNING AS SATELLITE INDICATING LINEAR BAND OF COOLING CLOUD TOPS DEVELOPING FROM GOODLAND TO NORTON. AM A LITTLE CONCERNED ABOUT ANOTHER POCKET OF ELEVATED INSTABILITY ASSOCIATED WITH WEAK SHORT WAVE TROUGH THAT HAS BEEN DRIFTING TO THE NORTH AND WOULD NOT BE OUT OF THE QUESTION TO SEE A CELL OR TWO ALONG SOUTHERN FRINGE OF CWA AS FRONT INTERACTS WITH THIS AREA. NOT REALLY SEEING ANY SIGNS OF THIS ON SATELLITE RIGHT NOW AND WOULD LIKE TO SEE SOME CONFIRMATION WITH MORNING SOUNDINGS BEFORE CHANGING FORECAST GREATLY. ASIDE FROM EARLY MORNING CONVECTION...REST OF FORECAST STILL ON TRACK && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 258 AM MDT WED JUL 25 2012 03Z WATER VAPOR IMAGERY INDICATED LARGE AREA OF SUBSIDENCE/DRYING THAT WAS OVER THE AREA THE PAST FEW DAYS HAD SHIFTED TO THE NORTHEAST...WITH SUBTLE SHORT WAVE TROUGH MOVING ACROSS SOUTHERN KANSAS WITH STRONG SHORT WAVE TROUGH MOVING ACROSS THE US/CANADIAN BORDER. 00Z RAOBS SHOWED LITTLE CHANGE IN THERMAL PROFILES ACROSS THE AREA WITH LARGEST CHANGES NOTED AT DDC WHERE TEMPS BELOW H7 HAS WARMED AROUND 2C AND TEMPS BTWN H7 AND H5 HAD COOLED AROUND 2C. PRIMARY FORECAST CONCERN WILL BE PRECIPITATION CHANCES TODAY AND TONIGHT...FOLLOWED BY TEMPS THROUGH THE START OF THE WEEKEND. TODAY...COLD FRONT IS CURRENTLY ADVANCING ACROSS THE CWA AND WILL CONTINUE TO ADVANCE TO THE SOUTH BEFORE STALLING ACROSS SOUTHERN PORTION OF THE CWA LATE THIS MORNING. ALREADY SEEING A FEW SHOWERS AND THUNDERSTORMS POP UP BEHIND THE FRONT...ALTHOUGH PRECIP AMOUNTS LOOK TOP BE VERY SPOTTY AS UPDRAFTS REMAIN WEAK AND SHORT LIVED. POCKET OF LOW CINH AND WEAK INSTABILITY LOCATED AROUND H7 AND AREA OF FRONTOGENESIS LINE UP WITH CURRENT ACTIVITY PRETTY WELL AND GENERAL TRENDS WITH THESE FIELDS SUGGEST ACTIVITY SHOULD REMAIN CONFINED TO THE NORTHWESTERN CWA DURING THE MORNING HOURS. LARGE SCALE FORCING FOR ASCENT BEGINS TO INCREASE AS SHORT WAVE TROUGH APPROACHES NEB PANHANDLE AND DRIFTS TO THE SOUTHEAST. INITIALLY THOUGHT THAT PRECIPITATION WOULD STRUGGLE TO DEVELOP CLOSER TO STRONGER UPPER LEVEL FORCING AND INSTEAD FAVOR FRONTAL ZONE TO THE SOUTH BUT SEEING AS LIMITED INSTABILITY ALREADY BEING REALIZED...THINK COVERAGE WILL IMPROVES AS FORCING INCREASES...BEFORE SFC FRONT BECOMES PRIMARY FOCUS FOR STORMS LATE IN THE AFTERNOON. TONIGHT...BIG QUESTION FOR THE OVERNIGHT PERIOD WILL BE HOW LONG PRECIPITATION LINGERS ACROSS THE AREA. WHILE PERIOD OF LARGE SCALE FORCING FOR ASCENT AND MID LEVEL FRONTOGENESIS ARE IN PLACE ACROSS MUCH OF THE AREA AT 00Z...THESE FIELDS DIMINISH CONSIDERABLY DURING THE EVENING HOURS AND THINK BULK OF PRECIPITATION WILL BE TIED TO FRONTAL ZONE WHICH WILL BE MOVING QUICKLY OUT OF THE CWA. WHILE INITIAL THOUGHTS ARE MUCH OF THE CWA WILL BE DONE WITH PRECIPITATION AROUND 00Z...HAVE SOME CONCERNS THAT SOUNDINGS INDICATE SOME POTENTIAL DESTABILIZATION ACROSS EASTERN COLORADO AFTER FRONT PASSES. NOT SURE I CAN PUT REALLY GREAT CONFIDENCE INTO THIS SOLUTION...BUT WITH LATEST GEFS AS WELL AS LOCAL NEIGHBORHOOD PRECIPITATION GUIDANCE THINK LINGERING HIGHER POPS INTO AT LEAST 2Z IS WARRANTED. TOMORROW...NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ACROSS THE AREA AS H5 RIDGE AMPLIFIES OVER THE ROCKIES WITH SFC HIGH BRINGING FAIRLY LIGHT AND VARIABLE WINDS ACROSS THE CWA. WHILE THERE IS NOT IN THE WAY OF LARGE SCALE FORCING...GENERAL MODELS INDICATE SFC HEATING WILL BE ENOUGH TO REMOVE MUCH OF THE CINH ASSOCIATED WITH INSTABILITY AXIS THAT DEVELOPS ACROSS COLORADO. NOT REALLY CONFIDENT IN PRECIP CHANCES OR COVERAGE...BUT THINK CURRENT ISOLATED CHANCES IN THIS AREA LOOK REASONABLE ATTM. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 258 AM MDT WED JUL 25 2012 THURSDAY NIGHT-FRIDAY NIGHT...DESPITE SLOWLY AMPLIFYING RIDGE ACROSS THE AREA...THERE WILL BE PERIODS OF LARGE SCALE FORCING FOR ASCENT THROUGH THE PERIOD AS RIDGE AXIS REMAINS TO THE WEST OF THE AREA AND A FEW SMALL SHORT WAVE TROUGHS MOVE OVER THE TOP OF THE RIDGE AND IMPACT THE AREA. SOME DIFFERENCES EXIST WITH RESPECT TO HOW STRONG UPCOMING RIDGE WILL BE WHICH WILL STRONGLY IMPACT HOW MUCH INFLUENCE ANY OF THESE SMALL SCALE TROUGHS WILL HAVE. WHILE NAM AND SREF QUITE AGGRESSIVE DEVELOPING CONVECTION ACROSS NORTHERN CWA...GFS AND GEFS MUCH DRIER. FOR NOW...THINK GEFS SOLUTION OF 15-20 POPS REFLECTS THE EXPECTED PATTERN PRETTY WELL. THE NEXT UPPER LEVEL RIDGE WILL BUILD OVER THE INTERMOUNTAIN WEST AND OVER THE ROCKIES BY THIS WEEKEND. A FEW SHORTWAVE TROUGHS WILL MOVE THROUGH THE FLOW DURING THE PERIOD AND WITH SURFACE TROUGH DEEPENING ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED AFTERNOON THUNDERSTORMS MOST DAYS. BY EARLY NEXT WEEK...THE RIDGE WILL MOVE EASTWARD INTO THE PLAINS WITH THE MAIN CENTER OF THE HIGH POSITIONED ACROSS THE SOUTHERN PLAINS REGION MONDAY BEFORE RETROGRADING BACK INTO THE SOUTHERN ROCKY MOUNTAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1101 AM MDT WED JUL 25 2012 SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE FROM THE SOUTHWEST TO THE NORTHEAST EARLY IN THE TAF PERIOD. THUNDERSTORMS WILL INCREASE IN COVERAGE AS UPPER LEVEL DISTURBANCE SHIFTS SOUTH AND EAST OVER THE AREA...WITH THUNDERSTORM ACTIVITY POSSIBLY IMPACTING TERMINALS LATE THIS AFTERNOON AND EARLY THIS EVENING. GUSTY NORTH WINDS WILL CONTINUE THROUGH THE AFTERNOON AND THEN DECREASE BY THIS EVENING AS FRONTAL ZONE SHIFTS SOUTHEAST. MVFR CONDITIONS IS POSSIBLE LATE TONIGHT/EARLY THURSDAY MORNING AT KMCK AS A RESULT OF PATCHY FOG DEVELOPING UNDER SURFACE HIGH PRESSURE. CONFIDENCE WAS TOO LOW TO PREVAIL THESE CONDITIONS AT THIS TAF ISSUANCE...SO LEFT VIS/CIGS VFR FOR NOW. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...JRM LONG TERM...JRM/PMM AVIATION...DR
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
150 PM EDT WED JUL 25 2012 .SYNOPSIS... ISSUED AT 345 AM EDT WED JUL 25 2012 A WARM FRONT WILL BRING POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY MAINLY NORTH OF INTERSTATE 96 THIS AFTERNOON. IT WILL BECOME HOT AND HUMID LATER TODAY SOUTH OF THE WARM FRONT. STRONG LOW PRESSURE TRACKING EAST ALONG THE WARM FRONT AND AN APPROACHING COLD FRONT WILL COMBINE TO BRING POTENTIAL FOR STRONG TO SEVERE STORMS TONIGHT THAT MAY PRODUCE DAMAGING WIND GUSTS AND HEAVY RAIN. TEMPERATURES WILL RETURN TO CLOSER TO NORMAL BEHIND THAT FRONT THURSDAY AND FRIDAY WITH A CONTINUED CHANCE OF SOME SHOWERS AND STORMS. FAIR WEATHER IS ANTICIPATED THIS WEEKEND. && .UPDATE... ISSUED AT 1224 PM EDT WED JUL 25 2012 AREA OF SHOWERS AND STORMS HAVE TRIED TO MOVE INTO THE FORECAST AREA THIS MORNING. FOR THE MOST PART THESE SHOWERS AND STORMS HAVE DISSIPATED AS THEY MOVE INTO MUCH LESS INSTABILITY AND MOISTURE. THE BETTER INSTABILITY DOES NOT MOVE INTO THE AREA UNTIL LATE THIS AFTERNOON AND EVENING. THE NEXT FEW HOURS LOOK TO BE QUIET. THE MAIN FOCUS FOR SHOWERS AND STORMS WILL BE FROM EARLY EVENING...500PM-600PM THROUGH 100AM-200AM. ADDITIONAL STORMS ARE EXPECTED OVERNIGHT. A COUPLE OF SCENARIOS ARE POSSIBLE FOR LATER TODAY. THE FIRST SCENARIO IS THAT STORMS TO THE NORTH AND WEST WILL MOVE INTO THE CWA FROM THE NORTH AND WEST AFTER DEVELOPING THIS AFTERNOON. THE SECOND IS STORMS FIRE ALONG OUTFLOWS FROM PRIOR CONVECTION VERY NEAR THE CWA OR OVER THE NORTHERN CWA THIS AFTERNOON AND EVENING. EITHER WAY WE ARE EXPECTED STORMS TO PRESS INTO AND MOVE THROUGH THE NORTHERN HALF OR SO OF THE FORECAST AREA...ROUGHLY I96 NORTH...THIS EVENING. DAMAGING WINDS LOOK TO BE THE MAIN THREAT AS 40-50 KNOTS OF WIND WILL BE PRESENT BETWEEN 850MB AND 500MB/S. 35 TO 45 KNOTS OF 0-6KM SHEAR IS PRESENT AS WELL WHICH WILL AID THUNDERSTORM UPDRAFTS AND ALLOW FOR ROTATION. IF DISCRETE STORMS CAN DEVELOP AND MOVE ALONG BOUNDARIES A TORNADO THREAT MAY DEVELOP AS WELL. DAMAGING WINDS WILL AGAIN BE THE MAIN THREAT WITH A MUCH LOWER TORNADO AND HAIL THREAT. FREEZING LEVELS SHOULD RISE TO AROUND 16000FT SO ONLY THE STRONGEST OF UPDRAFTS WOULD BE CAPABLE OF SEVERE HAIL. CANNOT RULE OUT SEVERE STORMS OVERNIGHT AS WELL AS INSTABILITY WILL PERSIST GIVEN HIGH DEW POINTS AND THE 850MB LLJ WILL BE OVERHEAD. MAIN TIME FRAME OF CONCERN THOUGH IS THIS EVENING. && .SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON) ISSUED AT 345 AM EDT WED JUL 25 2012 OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE TIMING/PROBABILITIES FOR CONVECTION THROUGH THE SHORT TERM FCST PERIOD AND TO ASSESS SEVERE WX POTENTIAL. THE SETUP LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS TONIGHT AS A STRONG LOW PRESSURE WAVE TRACKS EAST ALONG THE WARM FRONT AND COLD FRONT APPROACHES. THERE WILL BE PLENTY OF MOISTURE AND DECENT INSTABILITY ALONG WITH LIFT FROM THE APPROACHING FRONT. DEEP LAYER SHEAR VALUES RAMPING UP TO 35 TO 40 KTS ARE ALSO FAVORABLE FOR ORGANIZED SEVERE STORMS. 00Z 4KM WRF-NMM SIM Z GUIDANCE SHOWS CONVECTIVE DEVELOPMENT ACROSS OUR AREA FROM 00Z THRU 12Z TONIGHT. 00Z 4KM NSSL WRF GUIDANCE ALSO SHOWS POTENTIAL TONIGHT ESPECIALLY OVER OUR NORTHERN COUNTIES WHICH IS ALSO SUPPORTED BY THE 00Z ECMWF. AN ISOLATED TORNADO IS POSSIBLE EARLY TO MID EVENING WITH A SOMEWHAT VEERED WIND PROFILE WITH HEIGHT AND DEEP LAYER SHEAR VALUES CONDUCIVE TO SUPERCELLS. DAMAGING WIND GUSTS SHOULD BE THE MOST LIKELY SEVERE WX THREAT BUT HEAVY RAINFALL IS ALSO POSSIBLE. PRECIPITABLE WATER VALUES WILL REACH 1.75 TO 2.25 INCHES JUST AHEAD OF THE APPROACHING COLD FRONT ALONG WITH DECENT LOW TO MID LEVEL MOISTURE POOLING ALONG/AHEAD OF THE FRONT. THE GREATEST THREAT FOR SVR WX SHOULD COME FROM AROUND 23Z THIS EVE THROUGH 06Z THUR WITH GREATER INSTABILITY IN PLACE THROUGH THE EVENING HOURS AND WITH THE CRAVEN BROOKS SIG SVR PARAMETER UP AROUND 40-50K. THIS IS ALSO THE WINDOW OF TIME THAT THE SUPERCELL COMPOSITE PARAMETER IS FCST TO BE WAY UP AROUND A VALUE OF 12. THE SIG TOR PARAMETER REACHES VALUES OF 1 TO 4 FROM EARLY TO MID EVENING BEFORE DROPPING OFF OVERNIGHT. THE BEST CHC FOR AN ISOLATED TORNADO THIS EVE WOULD BE OVER OUR NORTHERN COUNTIES IN CLOSER PROXIMITY TO THE WARM FRONT WHERE 0-1KM AND 0-3KM SRH VALUES WILL BE ENHANCED. THE THREAT FOR SOME SEVERE STORMS WILL LINGER EVEN AFTER 06Z TONIGHT THROUGH AT LEAST DAYBREAK IF NOT MIDDAY THURSDAY... THE POTENTIAL JUST WILL NOT BE QUITE AS FAVORABLE AS BETWEEN 23Z-06Z TONIGHT AS SUGGESTED BY A CONSENSUS OF SPC SREF SVR WX PARAMETERS. THIS NOTION IS ALSO SUPPORTED BY OUR LOCAL SEVERE WX CLIMATOLOGY. THE FCST FOR THIS MORNING AND AFTERNOON IS TRICKY. MOST OF THE HIGHER RESOLUTION GUIDANCE SUGGESTS THE BETTER THREAT FOR CONVECTION LATER THIS MORNING WILL BE ACROSS NORTHERN MICHIGAN AS THE WARM FRONT LIFTS NORTH. HOWEVER SIGNIFICANT CONVECTIVE DEVELOPMENT IS NOTED EARLY THIS MORNING ACROSS CENTRAL MN. I AM CONCERNED ABOUT MCS PROPAGATION THICKNESS TOOLS WHICH SUGGEST THAT THIS WILL DIVE SE OR EVEN SSE EVENTUALLY ACROSS WI LATER THIS MORNING. IF THIS ACTIVITY HOLDS TOGETHER WE COULD ALREADY BE DEALING WITH A ROUND OF STRONG TO SEVERE STORMS HERE BY EARLY TO MID AFTERNOON PARTICULARLY OVER OUR NORTHERN COUNTIES. UPSTREAM RGNL RADAR TRENDS WILL NEED TO BE MONITORED VERY CLOSELY THROUGH THE MORNING. IT IS NOTED THAT THE SPC SREF DERECHO COMPOSITE PARAMETER REACHES VALUES OF 2-3 ACROSS WI THIS MORNING AND THEN OVER LWR MI BY THIS AFTN. EXTRAPOLATION OF LATEST HRRR GUIDANCE ALSO SHOWS THE THREAT FOR CONVECTION OVER OUR NORTHERN COUNTIES TOWARD MID AFTN. STILL LOOKING FOR LINGERING SHOWERS/TSTORMS THURSDAY. CANNOT RULE OUT SOME STRONG TO SEVERE STORMS ESPECIALLY OVER OUR SE FCST AREA THRU MIDDAY UNTIL THE COLD FRONT CLEARS THAT AREA. SOME STORMS MAY STILL LINGER EVEN THROUGH THE AFTERNOON AIDED BY A COUPLE OF FAIRLY STRONG SHORTWAVES TRACKING EAST ACROSS THE AREA. HOWEVER THE SVR WX THREAT BY THURSDAY AFTERNOON SHOULD BE FURTHER SOUTH ACROSS IN/OH. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 345 AM EDT WED JUL 25 2012 THE UPPER LOW OVER SASKATCHEWAN IS PROGGED TO DROP SOUTHEAST ACROSS THE GREAT LAKES REGION THURSDAY NIGHT AND FRIDAY. AS THIS FEATURE AND ASSOCIATED COLDER TEMPS ALOFT COME OVERHEAD ON FRIDAY AND COMBINE WITH SFC HEATING/INSTABILITY ... COVERAGE OF SHOWER/TSTMS SHOULD INCREASE BY AFTERNOON. A WEAK SFC TROUGH DROPPING SOUTH THROUGH LWR MI ON FRIDAY IS EXPECTED TO ENHANCE SFC CONVERGENCE. SHOWERS WILL END FRIDAY EVENING AS THE WAVE MOVES OUT AND DRIER ARRIVES FROM THE NORTH. MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AN AREA OF SFC HIGH PRESSURE DRIFTING SLOWLY EAST ACROSS THE GREAT LAKES OVER THE COMING WEEKEND. A PLEASANT/COMFORTABLE AIR MASS IS EXPECTED TO ACCOMPANY THIS FEATURE WITH DEW POINTS AROUND 60. HIGHS SHOULD BE IN THE LOWER TO MID 80S WITH LOWS AROUND 60. SHOWER/TSTM CHANCES WILL BE REINTRODUCED EARLY NEXT WEEK AS THE AIR MASS GRADUALLY BECOMES A BIT WARMER AND INCREASINGLY HUMID ON THE BACK SIDE OF THE SFC HIGH. HOWEVER RIGHT NOW THE CHANCES FOR RAIN DO NOT LOOK PARTICULARLY GOOD... WITH ONLY ISOLATED TO WIDELY SCATTERED COVERAGE EXPECTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 150 PM EDT WED JUL 25 2012 THE MAIN CONCERN TO AVIATION INTERESTS WITH THIS SET OF FCSTS IS CONVECTIVE TRENDS...ESPECIALLY THIS EVENING. LATEST DATA IS STARTING TO CONVERGE ON THE EXPECTED EVOLUTION OF STORMS FOR THIS EVENING. WE ARE EXPECTING A BAND OF STORMS TO DEVELOP NORTHWEST OF THE AREA NEAR KGRB AROUND 22-23Z TONIGHT. THESE ARE EXPECTED TO MOVE SE THROUGH THE EVENING AND INTO THE EARLY OVERNIGHT HOURS. WE EXPECT THEM AROUND KMKG AROUND 00-01Z AND THEN REACHING THE KJXN AREA AROUND 03-04Z. WIND GUSTS WILL BE THE MAIN THREAT ALONG WITH THE NORMAL STORM HAZARDS. SOME RESIDUAL SHOWERS WILL BE LIKELY BEHIND THE MAIN LINE OF STORMS. MODELS ARE INDICATING SOME LOW CLOUDS MOVING IN BEHIND THE FRONT...SIMILAR TO WHAT IS GOING ON CURRENTLY BEHIND THE FRONT. ENOUGH WIND SHOULD BE IN PLACE TO KEEP FOG FROM BEING A BIG ISSUE. WINDS WILL BECOME NW. THE LOWER CLOUDS SHOULD LIFT INTO A VFR DECK DURING THE MID TO LATE MORNING HOURS ON THU. THE SRN TERMINALS COULD SEE ANOTHER ROUND OF SHOWERS/STORMS THU AFTERNOON...HOWEVER THE CONFIDENCE IN THAT RIGHT NOW IS TOO LOW TO MENTION AT THIS TIME. && .MARINE... ISSUED AT 1224 PM EDT WED JUL 25 2012 WILL BE ISSUING A SMALL CRAFT ADVISORY AND A BEACH HAZARDS STATEMENT FOR GRAND HAVEN NORTHWARD. THE TIME FRAME WILL BE FROM THE CURRENT TIME THROUGH 400 AM TONIGHT WITH THE MAIN TIME FRAME BEING THIS AFTERNOON AND EVENING. WAVES HAVE ALREADY BUILT TO NEAR 6.5 FEET AT THE LUDINGTON BUOY WITH SOUTHERLY WINDS IN THE 20-30 KNOT RANGE IN THE NORTHERN NEARSHORE WATERS BASED ON OBSERVATIONS. WEBCAMS ON THE COAST ARE SHOWING WHITECAPS FROM MUSKEGON NORTHWARD. THE WIND SHOULD TONE DOWN OVERNIGHT WITH THE THREAT POTENTIALLY SHIFTING SOUTH OF GRAND HAVEN INTO THURSDAY MORNING. A SCA AND BH.S MAY BE NEEDED FROM DAYBREAK INTO THE AFTERNOON ON THURSDAY. THIS THREAT WILL BE REEVALUATED OVERNIGHT. && .HYDROLOGY... ISSUED AT 345 AM EDT WED JUL 25 2012 RIVER LEVELS REMAIN LOW AND RAINFALL IS NOT EXPECTED TO BE HEAVY ENOUGH TO CAUSE SIGNIFICANT RIVER FLOODING ISSUES. HOWEVER THUNDERSTORMS MAY CAUSE URBAN AND SMALL STREAM TYPE FLOODING ISSUES TONIGHT WITH HIGH PRECIPITABLE WATER VALUES IN PLACE IN ADVANCE OF THE APPROACHING COLD FRONT TONIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ037-043-050. LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT THURSDAY FOR LMZ847>849. && $$ UPDATE...DUKE SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MEADE AVIATION...NJJ HYDROLOGY...LAURENS MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
148 PM EDT WED JUL 25 2012 .UPDATE... ISSUED AT 1232 PM EDT WED JUL 25 2012 HAVE MADE SOME ADJUSTMENTS TO THE SHORT TERM GRIDS TO BETTER LINE UP WITH THE CURRENT TRENDS ON THE SHOWERS/THUNDERSTORMS MOVING THROUGH CNTRL/ERN UPPER MI AND THEN BREAKS IN THE CLOUDS OVER THE WEST HALF. THIS MORNING...MOST OF THE CWA RECEIVED OVER A HALF INCH OF RAIN WITH SEVERAL LOCATIONS OVER THE WEST AND CENTRAL OVER AN INCH. LARGEST TOTAL SO FAR WAS NEAR ROCKLAND...WHERE NEARLY 3 INCHES FELL. BROAD SFC TROUGH OVER ERN MN AND POTENTIALLY TWO LOW PRESSURE AREAS...ONE NEAR DULUTH AND THE OTHER IN SCNTRL MN. TO THE EAST OF THIS BROAD LOW PRESSURE AREA...A WARM FRONT LOOKS TO BE SITUATED EAST ACROSS CNTRL WI. THIS WARM FRONT IS THE MAIN ITEM OF CONCERN...AS THERE HAVE BEEN DIFFERENCES IN THE SHORT TERM HIGH RES MODEL RUNS ON HOW FAR N IT TRACKS. WITH SOME CLEARING IN WRN WI AND EVEN INTO WRN UPPER MI...THINKING THAT REDEVELOPMENT WILL OCCUR IN WRN WI ON THE DIFFERENTIAL HEATING AREA AND WITH RESIDUAL CONVECTION COMING OUT OF CNTRL MN. THIS CO-LOCATED WHERE THE INSTABILITY IS QUICKLY INCREASING TO 1500-2500 J/KG OF SBCAPE. IF CONVECTION DEVELOPS THERE...SHOULD QUICKLY SEE STRONG/SEVERE STORMS AS 0-6KM SHEAR VALUES APPROACH 50KTS. WITH THE EXPECTED STORM MOTION A GENERAL ERLY DIRECTION...THINK THE BEST SHOT OF STRONG/SEVERE STORMS WILL BE ALONG THE WI BORDER THROUGH THE AFTN AND TOWARDS EARLY EVENING OVER THE SCNTRL. WITH THE CLEARING SEEN OVER PORTIONS OF WRN UPPER MI...LINGERING MID LVL WAA...AND RIGHT REAR AREA OF UPPER JET...COULD ALSO SEE SOME DEVELOPMENT FARTHER N THAN THE MAIN AREA...SO WILL CONTINUE TO MENTION ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS OVER THE WEST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED JUL 25 2012 ACTIVE WEATHER MORNING AS COMPLEX OF THUNDERSTORMS THAT HAS FORMED OVR NORTHERN MN IS POISED TO IMPACT MUCH OF CWA THROUGH AT LEAST EARLY AFTN. TSRA OVR WCNTRL INTO NORTHERN MN DEVELOPED IN AREA OF PVA FM SHORTWAVE LIFTING INTO NORTHERN MN AND WAS ALSO TIED TO H85-H7 MOISTURE ADVECTION/H7 FGEN AND RIGHT ENTRANCE JET FORCING/ISENTROPIC LIFT ON 300-305K SFC. COMPLEX IS WELL TO NORTH OF SFC WARM FRONT...MORE IN LINE WITH NORTHERN GRADIENT OF MLCAPE OVR 2000 J/KG AND WITHIN AREA OF SUFFICIENT DEEP LAYER SHEAR OVR 40 KTS. 0-1KM SHEAR TO 40 KTS HAS ALLOWED COLD POOLS TO DEVELOP AND BRIEFLY PROPAGATE EASTWARD. MOST WIND GUSTS WITH ACTIVITY HAVE BEEN IN THE 30-40 KT RANGE. COMPLEX WILL CONTINUE EASTWARD BUT MAY LOSE SOME PUNCH AS IT STRAYS AWAY FM GRADIENT OF MLCAPE. H85-H3 THICKNESSES SUGGEST ANY STONGER LINEAR SEGMENTS MAY TRY TO DRIFT ESE AS THE COMPLEX PUSHES NEAR IWD WITHIN THE NEXT 2-3 HRS. NO REAL BIG CHANGE TO PREVIOUS FCST...THOUGH THAT IS PARTIALLY DUE TO A LOT OF SCENARIOS OFFERED UP BY VARIOUS GUIDANCE ON HOW THIS COMPLEX WILL TRANSLATE TO THE EAST THE NEXT FEW HOURS. WENT WITH A CONSENSUS FM ALL THE SOLUTIONS ALONG WITH PREVIOUS FCST. OVERALL FEEL FAIRLY CONFIDENT THAT BTWN ONGOING/STRONG H85 MOISTURE TRANSPORT ON NOSE OF H85 JET AND DIVERGENCE ALOFT...THAT THE OVERALL COMPLEX WILL CONTINUE TO TRACK ON A GENERAL EASTWARD MOVEMENT ACROSS UPR MICHIGAN THROUGH EARLY AFTN...ON SOUTH EDGE OF SHORTWAVE MOVING ACROSS NORTHERN LK SUPERIOR AND STILL WELL TO NORTH OF SFC WARM FRONT. LATEST RENDITION OF RAPID REFRESH RUC /HRRR/ SHOWS THIS PRETTY WELL AND INDICATES THAT MAJORITY OF PRECIP WILL BE DONE BY EARLY AFTN OVR WEST HALF AND SOON THERE AFTER IN THE EAST. WHAT HAPPENS BY MID TO LATE AFTN IS A CONCERN AS MODELS HAVE CERTAINLY TRENDED FARTHER NORTH WITH ADVANCING SFC WARM FRONT BY MID-LATE AFTN. SINCE IT APPEARS NOW THAT BULK OF CONVECTIVE COMPLEX THIS MORNING WILL JUST GRAZE SOUTHERN CWA IT IS MORE FEASIBLE THAT SOUTHERN CWA MAY SNEAK INTO WARM SECTOR THIS AFTN AND WITH GRADIENT OF 0-6KM MUCAPE WELL OVR 2000 J/KG OVERHEAD ALONG WITH ANOTHER SHORTWAVE WORKING THROUGH IN SPEEDY WESTERLY FLOW IN ADDITION TO MORE UPPER DIVERGENCE ALOFT...BEGINNING TO THINK AN ADDITIONAL ROUND OF SHRA/TSRA MAY DEVELOP BY LATE AFTN. IF CONVECTION BEHAVES LIKE IT HAS OVERNIGHT WITH MOST ACTIVITY OCCURRING ON GRADIENT OF MLCAPE...THEN PORTIONS OF CWA WOULD BE FAVORED FOR STRONG TSRA LINE SEGMENTS WITH STRONG/GUSTY WINDS. A LOT WILL DEPEND ON HOW QUICKLY COMPLEX MOVES THROUGH TODAY AND EXTENT OF DESTABILIZATION THAT CAN OCCUR LATE TODAY. THREAT FOR STORMS COULD LINGER INTO THE EVENING. LATER TONIGHT...STRONG UPPER LOW CURRENTLY OVR SOUTHERN SASKATCHEWAN WILL BE APPROACHING. H7-H3 Q-VECTOR CONVERGENCE AHEAD OF UPR LOW COULD TRIGGER ELEVATED CONVECTION. TROUBLE IS MOISTURE IS HEAVY IN THE LOW-LEVELS BUT REALLY DRYING OUT IN THE MID-UPR LEVELS. KEPT SOME SLIGHT CHANCES IN FCST BUT BETTER CHANCES LIKELY HOLD OFF TIL AFTER DAYBREAK ON THURSDAY. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 439 AM EDT WED JUL 25 2012 BEGINNING OF THE PERIOD WILL INCLUDE A CLOSED 500MB LOW OVER NORTHERN MN THAT WILL TRACK SOUTHEASTWARD WHILE LOSING STRENGTH...CROSSING THE UPPER GREAT LAKES BY NIGHTFALL. AS IT NEARS...MODEL SOUNDINGS ARE HINTING AT ABUNDANT LEFTOVER MOISTURE FROM WEDNESDAY/S EXITING SYSTEM...SO WILL CONTINUE WITH PREVIOUS FORECASTS MENTION OF CLOUDY SKIES...COOLER CONDITIONS...AND A SLIGHT CHANCE FOR SHRA. THICK CLOUD COVER FROM THE LOW LEVELS UPWARDS WILL PREVENT MUCH IN THE WAY OF RADIATIVE HEATING...SO WILL KEEP TEMPS BELOW NORMAL...BARELY REACHING THE 70 MARK NEAR LAKE SUPERIOR. ALL MODELS SEEM TO BE IN GOOD AGREEMENT OF SOME PRECIP TRAVERSING UPPER MI THURSDAY NIGHT AS A RESULT OF THIS UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE WARM FRONT. THOUGH PWAT VALUES ARE ONLY 100-120 PERCENT OF NORMAL...ABUNDANT LINGERING MOISTURE MENTIONED ABOVE SHOULD BE ENOUGH TO SPARK SOME PRECIP ALONG THE MAIN LINE OF CONVERGENCE/WARM FRONT/ AS IT PASSES OVER. HOWEVER...A PROBLEM PERSISTS ON THE EXACT LOCATION OF THE PRECIP AND CONVERGENCE...AS EVERY MODEL SEEMS TO HAVE A SLIGHTLY DIFFERENT SOLUTION IN WHICH PART OF UPPER MI WILL SEE THE BEST RAINFALL CHANCES THURSDAY NIGHT INTO FRIDAY. LATEST NAM SHOWS BEST MU CAPE VALUES TO ARRIVE WITH THE ONSET OF THE FRONTAL PASSAGE AND DIMINISH DURING THE OVERNIGHT HOURS /BY 03Z/...WITH HIGHEST VALUES /1-1.5 J/KG/ NEAR THE WISCONSIN BORDER. HOWEVER 0-3KM COMPUTED CAPE VALUES ONLY TOP OUT BETWEEN 2-300 J/KG...WITH THE NAM FORECASTED CAPE PROFILE VERY LONG AND SKINNY...INDICATIVE OF ONLY ISOLATED CHANCES. TO SUM UP THEN...A FEW RUMBLES OF THUNDER AND FLASHES OF LIGHTNING COULD BE POSSIBLE DURING THE EVENING WHEN INSTABILITY IS AT ITS BEST...BUT OTHERWISE AM LEANING TOWARDS THIS MAINLY BEING A HEAVY RAIN EVENT. 500MB SHORTWAVE WILL CONTINUE TO WEAKEN AS IT EXITS INTO THE LOWER GREAT LAKES DURING THE DAY FRIDAY. HOWEVER...LINGERING MOISTURE WILL MAKE FOR SIMILAR CONDITIONS TO THURSDAY...WITH THICK CLOUD COVER AND NRLY WINDS MAKING FOR MOIST AND COOLER THAN NORMAL CONDITIONS. MANY LOCATIONS WILL STRUGGLE TO GET INTO THE 70S. WITH THIS SET UP...WILL CONTINUE WITH SLIGHT CHANCE POPS DURING THE DAY FRIDAY IN THE WEST AND CENTRAL...IN THAT SOME LEFT OVER FORCING COULD BE ENOUGH TO SPAWN SOME SHRA/TSRA...WHILE BEST FORCING AND PRECIP CHANCES WILL LIE NEAR LAKE MICHIGAN. 500MB RIDGING PATTERN OVER THE NORTHERN PLAINS WILL BEGIN TO MOVE EASTWARD...WORKING ITS WAY INTO THE WESTERN PORTIONS OF THE CWA BY LATE FRIDAY AFTERNOON AS IS SEEN ON THE FORECAST SOUNDINGS...FIRST STARTING IN THE UPPER LEVELS AND THEN WORKING ITS WAY DOWN TO THE SURFACE. THIS WILL TRANSLATE TO RAPIDLY CLEARING SKIES FROM WEST TO EAST DURING THE OVERNIGHT HOURS AND LOWS DROPPING TO THE LOW TO MID 50S INLAND AWAY FROM THE WARMER LAKE INFLUENCE. 500MB RIDGE AND ASSOCIATED HIGH PRESSURE WILL CONTINUE TO DOMINATE THROUGH THE DAY ON SUNDAY. THIS WILL TRANSLATE TO MOSTLY SUNNY SKIES ACROSS THE REGION...LIGHT SOUTHERLY WINDS...AND HIGH TEMPERATURES RISING TO BACK ABOVE NORMAL. THE 500MB RIDGE SHOULD REMAIN IN PLACE THROUGHOUT THE REST OF THE FORECAST PERIOD...WITH SEVERAL WEAK SHORTWAVES TRAVERSING THE RIDGE AND UPPER GREAT LAKES. ALL LONG RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT SHORTWAVE AND RESULTING PRECIP WILL TRAVERSE THE UPPER GREAT LAKES SUNDAY EVENING INTO MONDAY WITH PW VALUES JUMPING BACK UP TO 100-120 PERCENT OF NORMAL. UNFORTUNATELY...AFTER THIS POINT MODELS START TO LOSE AGREEMENT ON TIMING AND LOCATIONS OF MENTIONED PRECIP SO WENT WITH MODEL CONSENSUS FOR REMAINDER OF FORECAST PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 147 PM EDT WED JUL 25 2012 A BREAK BEHIND THE SHOWERS AND THUNDERSTORMS THIS MORNING HAS LED TO HIGHER VSBYS/CIGS INTO THE VFR/MVFR RANGE. EXPECT THIS TO CONTINUE OVER THE NEXT COUPLE OF HOURS UNTIL SHOWERS AND THUNDERSTORMS TRY TO DEVELOP OVER NW WI AND POTENTIALLY AFFECT KIWD AND THEN KSAW. AFTER THIS POTENTIAL...SFC LOW WILL SLIDE E FROM ECNTRL MN INTO ERN WI. AS THIS OCCURS...EXPECT LLVL MOISTURE TO BE ON THE INCREASE AND AIDED BY UPSLOPE FLOW. THIS SHOULD LEAD TO IFR OR LOWER CIGS FROM LATE THIS EVENING INTO TOMORROW MORNING. BELIEVE THE BEST CHANCE OF CIGS/VSBY NEARING AIRFIELD LANDING MINS WILL BE AT KCMX/KSAW...WHERE THE UPSLOPE FLOW WITH THE BE MOST FAVORABLE. THE CIGS SHOULD LIFT SOME HEADING THROUGH TOMORROW MORNING AS THE UPSLOPE FLOW WEAKENS AND MIXING SLOWLY BRINGS THEM UP. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 439 AM EDT WED JUL 25 2012 LOW PRESSURE SYSTEM MOVES INTO WISCONSIN LATER TODAY AND INTO THE EASTERN GREAT LAKES ON THURSDAY MORNING AND INTO THE NEW ENGLAND STATES ON FRIDAY. THIS WILL LEAVE A WEAK SFC TROUGH OVER THE UPPER GREAT LAKES LATER TONIGHT THROUGH FRIDAY. HIGH PRESSURE WILL THEN MOVE OVER THE UPPER GREAT LAKES THIS WEEKEND...LEADING TO LIGHT WINDS OVER LK SUPERIOR. SOME STRONG E/SE WINDS POSSIBLE TODAY OVR EASTERN AND NORTHERN SECTIONS OF LK SUPERIOR OUT AHEAD OF THE LOW MOVING THROUGH AND THEN GUSTY ENE WINDS THIS EVENING IN WAKE OF THE LOW. OVERALL THOUGH...EXPECT WINDS TO STAY BELOW 20 KTS THROUGH THE WEEKEND. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...SRF SHORT TERM...JLA LONG TERM...JMW AVIATION...SRF MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 PM EDT WED JUL 25 2012 .UPDATE... ISSUED AT 1232 PM EDT WED JUL 25 2012 HAVE MADE SOME ADJUSTMENTS TO THE SHORT TERM GRIDS TO BETTER LINE UP WITH THE CURRENT TRENDS ON THE SHOWERS/THUNDERSTORMS MOVING THROUGH CNTRL/ERN UPPER MI AND THEN BREAKS IN THE CLOUDS OVER THE WEST HALF. THIS MORNING...MOST OF THE CWA RECEIVED OVER A HALF INCH OF RAIN WITH SEVERAL LOCATIONS OVER THE WEST AND CENTRAL OVER AN INCH. LARGEST TOTAL SO FAR WAS NEAR ROCKLAND...WHERE NEARLY 3 INCHES FELL. BROAD SFC TROUGH OVER ERN MN AND POTENTIALLY TWO LOW PRESSURE AREAS...ONE NEAR DULUTH AND THE OTHER IN SCNTRL MN. TO THE EAST OF THIS BROAD LOW PRESSURE AREA...A WARM FRONT LOOKS TO BE SITUATED EAST ACROSS CNTRL WI. THIS WARM FRONT IS THE MAIN ITEM OF CONCERN...AS THERE HAVE BEEN DIFFERENCES IN THE SHORT TERM HIGH RES MODEL RUNS ON HOW FAR N IT TRACKS. WITH SOME CLEARING IN WRN WI AND EVEN INTO WRN UPPER MI...THINKING THAT REDEVELOPMENT WILL OCCUR IN WRN WI ON THE DIFFERENTIAL HEATING AREA AND WITH RESIDUAL CONVECTION COMING OUT OF CNTRL MN. THIS CO-LOCATED WHERE THE INSTABILITY IS QUICKLY INCREASING TO 1500-2500 J/KG OF SBCAPE. IF CONVECTION DEVELOPS THERE...SHOULD QUICKLY SEE STRONG/SEVERE STORMS AS 0-6KM SHEAR VALUES APPROACH 50KTS. WITH THE EXPECTED STORM MOTION A GENERAL ERLY DIRECTION...THINK THE BEST SHOT OF STRONG/SEVERE STORMS WILL BE ALONG THE WI BORDER THROUGH THE AFTN AND TOWARDS EARLY EVENING OVER THE SCNTRL. WITH THE CLEARING SEEN OVER PORTIONS OF WRN UPPER MI...LINGERING MID LVL WAA...AND RIGHT REAR AREA OF UPPER JET...COULD ALSO SEE SOME DEVELOPMENT FARTHER N THAN THE MAIN AREA...SO WILL CONTINUE TO MENTION ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS OVER THE WEST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED JUL 25 2012 ACTIVE WEATHER MORNING AS COMPLEX OF THUNDERSTORMS THAT HAS FORMED OVR NORTHERN MN IS POISED TO IMPACT MUCH OF CWA THROUGH AT LEAST EARLY AFTN. TSRA OVR WCNTRL INTO NORTHERN MN DEVELOPED IN AREA OF PVA FM SHORTWAVE LIFTING INTO NORTHERN MN AND WAS ALSO TIED TO H85-H7 MOISTURE ADVECTION/H7 FGEN AND RIGHT ENTRANCE JET FORCING/ISENTROPIC LIFT ON 300-305K SFC. COMPLEX IS WELL TO NORTH OF SFC WARM FRONT...MORE IN LINE WITH NORTHERN GRADIENT OF MLCAPE OVR 2000 J/KG AND WITHIN AREA OF SUFFICIENT DEEP LAYER SHEAR OVR 40 KTS. 0-1KM SHEAR TO 40 KTS HAS ALLOWED COLD POOLS TO DEVELOP AND BRIEFLY PROPAGATE EASTWARD. MOST WIND GUSTS WITH ACTIVITY HAVE BEEN IN THE 30-40 KT RANGE. COMPLEX WILL CONTINUE EASTWARD BUT MAY LOSE SOME PUNCH AS IT STRAYS AWAY FM GRADIENT OF MLCAPE. H85-H3 THICKNESSES SUGGEST ANY STONGER LINEAR SEGMENTS MAY TRY TO DRIFT ESE AS THE COMPLEX PUSHES NEAR IWD WITHIN THE NEXT 2-3 HRS. NO REAL BIG CHANGE TO PREVIOUS FCST...THOUGH THAT IS PARTIALLY DUE TO A LOT OF SCENARIOS OFFERED UP BY VARIOUS GUIDANCE ON HOW THIS COMPLEX WILL TRANSLATE TO THE EAST THE NEXT FEW HOURS. WENT WITH A CONSENSUS FM ALL THE SOLUTIONS ALONG WITH PREVIOUS FCST. OVERALL FEEL FAIRLY CONFIDENT THAT BTWN ONGOING/STRONG H85 MOISTURE TRANSPORT ON NOSE OF H85 JET AND DIVERGENCE ALOFT...THAT THE OVERALL COMPLEX WILL CONTINUE TO TRACK ON A GENERAL EASTWARD MOVEMENT ACROSS UPR MICHIGAN THROUGH EARLY AFTN...ON SOUTH EDGE OF SHORTWAVE MOVING ACROSS NORTHERN LK SUPERIOR AND STILL WELL TO NORTH OF SFC WARM FRONT. LATEST RENDITION OF RAPID REFRESH RUC /HRRR/ SHOWS THIS PRETTY WELL AND INDICATES THAT MAJORITY OF PRECIP WILL BE DONE BY EARLY AFTN OVR WEST HALF AND SOON THERE AFTER IN THE EAST. WHAT HAPPENS BY MID TO LATE AFTN IS A CONCERN AS MODELS HAVE CERTAINLY TRENDED FARTHER NORTH WITH ADVANCING SFC WARM FRONT BY MID-LATE AFTN. SINCE IT APPEARS NOW THAT BULK OF CONVECTIVE COMPLEX THIS MORNING WILL JUST GRAZE SOUTHERN CWA IT IS MORE FEASIBLE THAT SOUTHERN CWA MAY SNEAK INTO WARM SECTOR THIS AFTN AND WITH GRADIENT OF 0-6KM MUCAPE WELL OVR 2000 J/KG OVERHEAD ALONG WITH ANOTHER SHORTWAVE WORKING THROUGH IN SPEEDY WESTERLY FLOW IN ADDITION TO MORE UPPER DIVERGENCE ALOFT...BEGINNING TO THINK AN ADDITIONAL ROUND OF SHRA/TSRA MAY DEVELOP BY LATE AFTN. IF CONVECTION BEHAVES LIKE IT HAS OVERNIGHT WITH MOST ACTIVITY OCCURRING ON GRADIENT OF MLCAPE...THEN PORTIONS OF CWA WOULD BE FAVORED FOR STRONG TSRA LINE SEGMENTS WITH STRONG/GUSTY WINDS. A LOT WILL DEPEND ON HOW QUICKLY COMPLEX MOVES THROUGH TODAY AND EXTENT OF DESTABILIZATION THAT CAN OCCUR LATE TODAY. THREAT FOR STORMS COULD LINGER INTO THE EVENING. LATER TONIGHT...STRONG UPPER LOW CURRENTLY OVR SOUTHERN SASKATCHEWAN WILL BE APPROACHING. H7-H3 Q-VECTOR CONVERGENCE AHEAD OF UPR LOW COULD TRIGGER ELEVATED CONVECTION. TROUBLE IS MOISTURE IS HEAVY IN THE LOW-LEVELS BUT REALLY DRYING OUT IN THE MID-UPR LEVELS. KEPT SOME SLIGHT CHANCES IN FCST BUT BETTER CHANCES LIKELY HOLD OFF TIL AFTER DAYBREAK ON THURSDAY. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 439 AM EDT WED JUL 25 2012 BEGINNING OF THE PERIOD WILL INCLUDE A CLOSED 500MB LOW OVER NORTHERN MN THAT WILL TRACK SOUTHEASTWARD WHILE LOSING STRENGTH...CROSSING THE UPPER GREAT LAKES BY NIGHTFALL. AS IT NEARS...MODEL SOUNDINGS ARE HINTING AT ABUNDANT LEFTOVER MOISTURE FROM WEDNESDAY/S EXITING SYSTEM...SO WILL CONTINUE WITH PREVIOUS FORECASTS MENTION OF CLOUDY SKIES...COOLER CONDITIONS...AND A SLIGHT CHANCE FOR SHRA. THICK CLOUD COVER FROM THE LOW LEVELS UPWARDS WILL PREVENT MUCH IN THE WAY OF RADIATIVE HEATING...SO WILL KEEP TEMPS BELOW NORMAL...BARELY REACHING THE 70 MARK NEAR LAKE SUPERIOR. ALL MODELS SEEM TO BE IN GOOD AGREEMENT OF SOME PRECIP TRAVERSING UPPER MI THURSDAY NIGHT AS A RESULT OF THIS UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE WARM FRONT. THOUGH PWAT VALUES ARE ONLY 100-120 PERCENT OF NORMAL...ABUNDANT LINGERING MOISTURE MENTIONED ABOVE SHOULD BE ENOUGH TO SPARK SOME PRECIP ALONG THE MAIN LINE OF CONVERGENCE/WARM FRONT/ AS IT PASSES OVER. HOWEVER...A PROBLEM PERSISTS ON THE EXACT LOCATION OF THE PRECIP AND CONVERGENCE...AS EVERY MODEL SEEMS TO HAVE A SLIGHTLY DIFFERENT SOLUTION IN WHICH PART OF UPPER MI WILL SEE THE BEST RAINFALL CHANCES THURSDAY NIGHT INTO FRIDAY. LATEST NAM SHOWS BEST MU CAPE VALUES TO ARRIVE WITH THE ONSET OF THE FRONTAL PASSAGE AND DIMINISH DURING THE OVERNIGHT HOURS /BY 03Z/...WITH HIGHEST VALUES /1-1.5 J/KG/ NEAR THE WISCONSIN BORDER. HOWEVER 0-3KM COMPUTED CAPE VALUES ONLY TOP OUT BETWEEN 2-300 J/KG...WITH THE NAM FORECASTED CAPE PROFILE VERY LONG AND SKINNY...INDICATIVE OF ONLY ISOLATED CHANCES. TO SUM UP THEN...A FEW RUMBLES OF THUNDER AND FLASHES OF LIGHTNING COULD BE POSSIBLE DURING THE EVENING WHEN INSTABILITY IS AT ITS BEST...BUT OTHERWISE AM LEANING TOWARDS THIS MAINLY BEING A HEAVY RAIN EVENT. 500MB SHORTWAVE WILL CONTINUE TO WEAKEN AS IT EXITS INTO THE LOWER GREAT LAKES DURING THE DAY FRIDAY. HOWEVER...LINGERING MOISTURE WILL MAKE FOR SIMILAR CONDITIONS TO THURSDAY...WITH THICK CLOUD COVER AND NRLY WINDS MAKING FOR MOIST AND COOLER THAN NORMAL CONDITIONS. MANY LOCATIONS WILL STRUGGLE TO GET INTO THE 70S. WITH THIS SET UP...WILL CONTINUE WITH SLIGHT CHANCE POPS DURING THE DAY FRIDAY IN THE WEST AND CENTRAL...IN THAT SOME LEFT OVER FORCING COULD BE ENOUGH TO SPAWN SOME SHRA/TSRA...WHILE BEST FORCING AND PRECIP CHANCES WILL LIE NEAR LAKE MICHIGAN. 500MB RIDGING PATTERN OVER THE NORTHERN PLAINS WILL BEGIN TO MOVE EASTWARD...WORKING ITS WAY INTO THE WESTERN PORTIONS OF THE CWA BY LATE FRIDAY AFTERNOON AS IS SEEN ON THE FORECAST SOUNDINGS...FIRST STARTING IN THE UPPER LEVELS AND THEN WORKING ITS WAY DOWN TO THE SURFACE. THIS WILL TRANSLATE TO RAPIDLY CLEARING SKIES FROM WEST TO EAST DURING THE OVERNIGHT HOURS AND LOWS DROPPING TO THE LOW TO MID 50S INLAND AWAY FROM THE WARMER LAKE INFLUENCE. 500MB RIDGE AND ASSOCIATED HIGH PRESSURE WILL CONTINUE TO DOMINATE THROUGH THE DAY ON SUNDAY. THIS WILL TRANSLATE TO MOSTLY SUNNY SKIES ACROSS THE REGION...LIGHT SOUTHERLY WINDS...AND HIGH TEMPERATURES RISING TO BACK ABOVE NORMAL. THE 500MB RIDGE SHOULD REMAIN IN PLACE THROUGHOUT THE REST OF THE FORECAST PERIOD...WITH SEVERAL WEAK SHORTWAVES TRAVERSING THE RIDGE AND UPPER GREAT LAKES. ALL LONG RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT SHORTWAVE AND RESULTING PRECIP WILL TRAVERSE THE UPPER GREAT LAKES SUNDAY EVENING INTO MONDAY WITH PW VALUES JUMPING BACK UP TO 100-120 PERCENT OF NORMAL. UNFORTUNATELY...AFTER THIS POINT MODELS START TO LOSE AGREEMENT ON TIMING AND LOCATIONS OF MENTIONED PRECIP SO WENT WITH MODEL CONSENSUS FOR REMAINDER OF FORECAST PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 747 AM EDT WED JUL 25 2012 SHRA/TSRA WORKING THROUGH UPPER MICHIGAN. EXPECT CONDITIONS TO DETERIORATE THROUGH THE DAY. RAIN COULD BE HEAVY AT TIMES...WITH VSBY LIKELY REDUCED TO AT LEAST MVFR RANGE THRU THE MORNING. SHOULD BE PRETTY QUICK LOWERING OF CIGS AS WELL INTO THE IFR RANGE AT BOTH CMX AND SAW. SLIGHTLY HIGHER CIGS AT IWD DUE TO LESS FAVORABLE EAST FLOW. EXPECT CONDITIONS TO DROP TO IFR/LIFR TNGT AT ALL SITES WITH LLVL MSTR LINGERING UNDER LGT UPSLOPE WIND COMPONENT OFF LK SUP/SOME MID LVL DRYING IN THE WAKE OF DEPARTING DISTURBANCE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 439 AM EDT WED JUL 25 2012 LOW PRESSURE SYSTEM MOVES INTO WISCONSIN LATER TODAY AND INTO THE EASTERN GREAT LAKES ON THURSDAY MORNING AND INTO THE NEW ENGLAND STATES ON FRIDAY. THIS WILL LEAVE A WEAK SFC TROUGH OVER THE UPPER GREAT LAKES LATER TONIGHT THROUGH FRIDAY. HIGH PRESSURE WILL THEN MOVE OVER THE UPPER GREAT LAKES THIS WEEKEND...LEADING TO LIGHT WINDS OVER LK SUPERIOR. SOME STRONG E/SE WINDS POSSIBLE TODAY OVR EASTERN AND NORTHERN SECTIONS OF LK SUPERIOR OUT AHEAD OF THE LOW MOVING THROUGH AND THEN GUSTY ENE WINDS THIS EVENING IN WAKE OF THE LOW. OVERALL THOUGH...EXPECT WINDS TO STAY BELOW 20 KTS THROUGH THE WEEKEND. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...SRF SHORT TERM...JLA LONG TERM...JMW AVIATION...JLA MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1225 PM EDT WED JUL 25 2012 .SYNOPSIS... ISSUED AT 345 AM EDT WED JUL 25 2012 A WARM FRONT WILL BRING POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY MAINLY NORTH OF INTERSTATE 96 THIS AFTERNOON. IT WILL BECOME HOT AND HUMID LATER TODAY SOUTH OF THE WARM FRONT. STRONG LOW PRESSURE TRACKING EAST ALONG THE WARM FRONT AND AN APPROACHING COLD FRONT WILL COMBINE TO BRING POTENTIAL FOR STRONG TO SEVERE STORMS TONIGHT THAT MAY PRODUCE DAMAGING WIND GUSTS AND HEAVY RAIN. TEMPERATURES WILL RETURN TO CLOSER TO NORMAL BEHIND THAT FRONT THURSDAY AND FRIDAY WITH A CONTINUED CHANCE OF SOME SHOWERS AND STORMS. FAIR WEATHER IS ANTICIPATED THIS WEEKEND. && .UPDATE... ISSUED AT 1224 PM EDT WED JUL 25 2012 AREA OF SHOWERS AND STORMS HAVE TRIED TO MOVE INTO THE FORECAST AREA THIS MORNING. FOR THE MOST PART THESE SHOWERS AND STORMS HAVE DISSIPATED AS THEY MOVE INTO MUCH LESS INSTABILITY AND MOISTURE. THE BETTER INSTABILITY DOES NOT MOVE INTO THE AREA UNTIL LATE THIS AFTERNOON AND EVENING. THE NEXT FEW HOURS LOOK TO BE QUIET. THE MAIN FOCUS FOR SHOWERS AND STORMS WILL BE FROM EARLY EVENING...500PM-600PM THROUGH 100AM-200AM. ADDITIONAL STORMS ARE EXPECTED OVERNIGHT. A COUPLE OF SCENARIOS ARE POSSIBLE FOR LATER TODAY. THE FIRST SCENARIO IS THAT STORMS TO THE NORTH AND WEST WILL MOVE INTO THE CWA FROM THE NORTH AND WEST AFTER DEVELOPING THIS AFTERNOON. THE SECOND IS STORMS FIRE ALONG OUTFLOWS FROM PRIOR CONVECTION VERY NEAR THE CWA OR OVER THE NORTHERN CWA THIS AFTERNOON AND EVENING. EITHER WAY WE ARE EXPECTED STORMS TO PRESS INTO AND MOVE THROUGH THE NORTHERN HALF OR SO OF THE FORECAST AREA...ROUGHLY I96 NORTH...THIS EVENING. DAMAGING WINDS LOOK TO BE THE MAIN THREAT AS 40-50 KNOTS OF WIND WILL BE PRESENT BETWEEN 850MB AND 500MB/S. 35 TO 45 KNOTS OF 0-6KM SHEAR IS PRESENT AS WELL WHICH WILL AID THUNDERSTORM UPDRAFTS AND ALLOW FOR ROTATION. IF DISCRETE STORMS CAN DEVELOP AND MOVE ALONG BOUNDARIES A TORNADO THREAT MAY DEVELOP AS WELL. DAMAGING WINDS WILL AGAIN BE THE MAIN THREAT WITH A MUCH LOWER TORNADO AND HAIL THREAT. FREEZING LEVELS SHOULD RISE TO AROUND 16000FT SO ONLY THE STRONGEST OF UPDRAFTS WOULD BE CAPABLE OF SEVERE HAIL. CANNOT RULE OUT SEVERE STORMS OVERNIGHT AS WELL AS INSTABILITY WILL PERSIST GIVEN HIGH DEW POINTS AND THE 850MB LLJ WILL BE OVERHEAD. MAIN TIME FRAME OF CONCERN THOUGH IS THIS EVENING. && .SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON) ISSUED AT 345 AM EDT WED JUL 25 2012 OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE TIMING/PROBABILITIES FOR CONVECTION THROUGH THE SHORT TERM FCST PERIOD AND TO ASSESS SEVERE WX POTENTIAL. THE SETUP LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS TONIGHT AS A STRONG LOW PRESSURE WAVE TRACKS EAST ALONG THE WARM FRONT AND COLD FRONT APPROACHES. THERE WILL BE PLENTY OF MOISTURE AND DECENT INSTABILITY ALONG WITH LIFT FROM THE APPROACHING FRONT. DEEP LAYER SHEAR VALUES RAMPING UP TO 35 TO 40 KTS ARE ALSO FAVORABLE FOR ORGANIZED SEVERE STORMS. 00Z 4KM WRF-NMM SIM Z GUIDANCE SHOWS CONVECTIVE DEVELOPMENT ACROSS OUR AREA FROM 00Z THRU 12Z TONIGHT. 00Z 4KM NSSL WRF GUIDANCE ALSO SHOWS POTENTIAL TONIGHT ESPECIALLY OVER OUR NORTHERN COUNTIES WHICH IS ALSO SUPPORTED BY THE 00Z ECMWF. AN ISOLATED TORNADO IS POSSIBLE EARLY TO MID EVENING WITH A SOMEWHAT VEERED WIND PROFILE WITH HEIGHT AND DEEP LAYER SHEAR VALUES CONDUCIVE TO SUPERCELLS. DAMAGING WIND GUSTS SHOULD BE THE MOST LIKELY SEVERE WX THREAT BUT HEAVY RAINFALL IS ALSO POSSIBLE. PRECIPITABLE WATER VALUES WILL REACH 1.75 TO 2.25 INCHES JUST AHEAD OF THE APPROACHING COLD FRONT ALONG WITH DECENT LOW TO MID LEVEL MOISTURE POOLING ALONG/AHEAD OF THE FRONT. THE GREATEST THREAT FOR SVR WX SHOULD COME FROM AROUND 23Z THIS EVE THROUGH 06Z THUR WITH GREATER INSTABILITY IN PLACE THROUGH THE EVENING HOURS AND WITH THE CRAVEN BROOKS SIG SVR PARAMETER UP AROUND 40-50K. THIS IS ALSO THE WINDOW OF TIME THAT THE SUPERCELL COMPOSITE PARAMETER IS FCST TO BE WAY UP AROUND A VALUE OF 12. THE SIG TOR PARAMETER REACHES VALUES OF 1 TO 4 FROM EARLY TO MID EVENING BEFORE DROPPING OFF OVERNIGHT. THE BEST CHC FOR AN ISOLATED TORNADO THIS EVE WOULD BE OVER OUR NORTHERN COUNTIES IN CLOSER PROXIMITY TO THE WARM FRONT WHERE 0-1KM AND 0-3KM SRH VALUES WILL BE ENHANCED. THE THREAT FOR SOME SEVERE STORMS WILL LINGER EVEN AFTER 06Z TONIGHT THROUGH AT LEAST DAYBREAK IF NOT MIDDAY THURSDAY... THE POTENTIAL JUST WILL NOT BE QUITE AS FAVORABLE AS BETWEEN 23Z-06Z TONIGHT AS SUGGESTED BY A CONSENSUS OF SPC SREF SVR WX PARAMETERS. THIS NOTION IS ALSO SUPPORTED BY OUR LOCAL SEVERE WX CLIMATOLOGY. THE FCST FOR THIS MORNING AND AFTERNOON IS TRICKY. MOST OF THE HIGHER RESOLUTION GUIDANCE SUGGESTS THE BETTER THREAT FOR CONVECTION LATER THIS MORNING WILL BE ACROSS NORTHERN MICHIGAN AS THE WARM FRONT LIFTS NORTH. HOWEVER SIGNIFICANT CONVECTIVE DEVELOPMENT IS NOTED EARLY THIS MORNING ACROSS CENTRAL MN. I AM CONCERNED ABOUT MCS PROPAGATION THICKNESS TOOLS WHICH SUGGEST THAT THIS WILL DIVE SE OR EVEN SSE EVENTUALLY ACROSS WI LATER THIS MORNING. IF THIS ACTIVITY HOLDS TOGETHER WE COULD ALREADY BE DEALING WITH A ROUND OF STRONG TO SEVERE STORMS HERE BY EARLY TO MID AFTERNOON PARTICULARLY OVER OUR NORTHERN COUNTIES. UPSTREAM RGNL RADAR TRENDS WILL NEED TO BE MONITORED VERY CLOSELY THROUGH THE MORNING. IT IS NOTED THAT THE SPC SREF DERECHO COMPOSITE PARAMETER REACHES VALUES OF 2-3 ACROSS WI THIS MORNING AND THEN OVER LWR MI BY THIS AFTN. EXTRAPOLATION OF LATEST HRRR GUIDANCE ALSO SHOWS THE THREAT FOR CONVECTION OVER OUR NORTHERN COUNTIES TOWARD MID AFTN. STILL LOOKING FOR LINGERING SHOWERS/TSTORMS THURSDAY. CANNOT RULE OUT SOME STRONG TO SEVERE STORMS ESPECIALLY OVER OUR SE FCST AREA THRU MIDDAY UNTIL THE COLD FRONT CLEARS THAT AREA. SOME STORMS MAY STILL LINGER EVEN THROUGH THE AFTERNOON AIDED BY A COUPLE OF FAIRLY STRONG SHORTWAVES TRACKING EAST ACROSS THE AREA. HOWEVER THE SVR WX THREAT BY THURSDAY AFTERNOON SHOULD BE FURTHER SOUTH ACROSS IN/OH. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 345 AM EDT WED JUL 25 2012 THE UPPER LOW OVER SASKATCHEWAN IS PROGGED TO DROP SOUTHEAST ACROSS THE GREAT LAKES REGION THURSDAY NIGHT AND FRIDAY. AS THIS FEATURE AND ASSOCIATED COLDER TEMPS ALOFT COME OVERHEAD ON FRIDAY AND COMBINE WITH SFC HEATING/INSTABILITY ... COVERAGE OF SHOWER/TSTMS SHOULD INCREASE BY AFTERNOON. A WEAK SFC TROUGH DROPPING SOUTH THROUGH LWR MI ON FRIDAY IS EXPECTED TO ENHANCE SFC CONVERGENCE. SHOWERS WILL END FRIDAY EVENING AS THE WAVE MOVES OUT AND DRIER ARRIVES FROM THE NORTH. MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AN AREA OF SFC HIGH PRESSURE DRIFTING SLOWLY EAST ACROSS THE GREAT LAKES OVER THE COMING WEEKEND. A PLEASANT/COMFORTABLE AIR MASS IS EXPECTED TO ACCOMPANY THIS FEATURE WITH DEW POINTS AROUND 60. HIGHS SHOULD BE IN THE LOWER TO MID 80S WITH LOWS AROUND 60. SHOWER/TSTM CHANCES WILL BE REINTRODUCED EARLY NEXT WEEK AS THE AIR MASS GRADUALLY BECOMES A BIT WARMER AND INCREASINGLY HUMID ON THE BACK SIDE OF THE SFC HIGH. HOWEVER RIGHT NOW THE CHANCES FOR RAIN DO NOT LOOK PARTICULARLY GOOD... WITH ONLY ISOLATED TO WIDELY SCATTERED COVERAGE EXPECTED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 754 AM EDT WED JUL 25 2012 THERE IS CONSIDERABLE UNCERTAINTY ON EXACTLY HOW THINGS ARE GOING TO PLAY OUT TODAY AND TONIGHT AS FAR AS TSTM ACTIVITY GOES. IN THE SHORT TERM... THE BAND OF TSTMS MOVING EAST FROM THE CHICAGO AND MKE AREAS EXTRAPOLATES EAST ACROSS SRN LWR MI BETWEEN ROUGHLY 14Z TO 18Z. THE CLOUD BASES... AS WELL AS THE VSBYS... WITH THESE TSTMS ARE MOSTLY IN THE VFR CATEGORY... BUT A TEMPO DIP INTO MVFR CATEGORY CANNOT BE RULED OUT ESPECIALLY AT GRR AND MKG. AFTER 18Z OR SO... WILL GO WITH THE IDEA THAT THE WARM SECTOR WILL SWEEP INTO THE REGION FROM THE SOUTHWEST AND THE ATMOSPHERE WILL BECOME TOO CAPPED /IE TOO WARM ALOFT/ FOR CONVECTION. SSW SFC WINDS SHOULD INCREASE AND BECOME GUSTY WITH THE ARRIVAL OF THE WARM SECTOR. WILL HOLD OFF ON REINTRODUCING TSTMS IN THE TAFS UNTIL AFTER 00Z AT MKG AND AFTER 03Z-04Z FARTHER SOUTH ALONG THE I-94 CORRIDOR. SOME GUIDANCE SUGGEST IT MAY EVEN BE LATER THAN THESE TIMES AS THE COLD FRONT ISNT REALLY DROPPING IN FROM THE NW UNTIL AFTER 06Z. && .MARINE... ISSUED AT 1224 PM EDT WED JUL 25 2012 WILL BE ISSUING A SMALL CRAFT ADVISORY AND A BEACH HAZARDS STATEMENT FOR GRAND HAVEN NORTHWARD. THE TIME FRAME WILL BE FROM THE CURRENT TIME THROUGH 400 AM TONIGHT WITH THE MAIN TIME FRAME BEING THIS AFTERNOON AND EVENING. WAVES HAVE ALREADY BUILT TO NEAR 6.5 FEET AT THE LUDINGTON BUOY WITH SOUTHERLY WINDS IN THE 20-30 KNOT RANGE IN THE NORTHERN NEARSHORE WATERS BASED ON OBSERVATIONS. WEBCAMS ON THE COAST ARE SHOWING WHITECAPS FROM MUSKEGON NORTHWARD. THE WIND SHOULD TONE DOWN OVERNIGHT WITH THE THREAT POTENTIALLY SHIFTING SOUTH OF GRAND HAVEN INTO THURSDAY MORNING. A SCA AND BH.S MAY BE NEEDED FROM DAYBREAK INTO THE AFTERNOON ON THURSDAY. THIS THREAT WILL BE REEVALUATED OVERNIGHT. && .HYDROLOGY... ISSUED AT 345 AM EDT WED JUL 25 2012 RIVER LEVELS REMAIN LOW AND RAINFALL IS NOT EXPECTED TO BE HEAVY ENOUGH TO CAUSE SIGNIFICANT RIVER FLOODING ISSUES. HOWEVER THUNDERSTORMS MAY CAUSE URBAN AND SMALL STREAM TYPE FLOODING ISSUES TONIGHT WITH HIGH PRECIPITABLE WATER VALUES IN PLACE IN ADVANCE OF THE APPROACHING COLD FRONT TONIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ037-043-050. LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT THURSDAY FOR LMZ847>849. && $$ UPDATE...DUKE SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...LAURENS MARINE...DUKE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
259 PM CDT WED JUL 25 2012 .DISCUSSION.../ISSUED 259 PM CDT WED JUL 25/ THE MAIN ISSUE IN THE SHORT TERM IS OBVIOUSLY THE CHANCES FOR SHRA/TSRA LATE THIS AFTERNOON INTO THIS EVENING AS THE SURFACE LOW SLIDES EAST AND THE FRONTAL BOUNDARY DROPS THROUGH THE AREA. LATEST MSAS ANALYSIS AND SURFACE OBS SHOW A WELL DEFINED WIND SHIFT CURRENTLY BISECTING THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST... AND SOME CONVECTION HAS TRIED TO DEVELOP NEAR THIS OVER THE PAST SEVERAL HOURS... BUT HAS THUS FAR BEEN UNSUCCESSFUL. THE ACTUAL FRONTAL BOUNDARY IS STILL WELL TO THE WEST OVER THE DAKOTAS... WHERE THE DEWPOINT GRADIENT CAN BE FOUND. THIS WILL EVENTUALLY BE PUSHED EAST THIS EVENING AS THE MAIN UPPER SHORTWAVE CURRENTLY SEEN NEAR THE SASKATCHEWAN/MANITOBA BORDER PUSHES SOUTHEAST. AT THIS POINT... IT/S QUESTIONABLE AS TO WHETHER THE FORCING ASSOCIATED WITH THE ACTUAL UPPER WAVE AND COLD FRONTAL BOUNDARY WILL MANAGE TO GET ANY CONVECTION GOING. CONTINUED CHANCE POPS THROUGH THE REMAINDER OF THE AFTERNOON OVER THE WESTERN CWFA TO ACCOUNT FOR THAT POSSIBILITY. OTHERWISE... TIED PCPN CHANCES TO THE INITIAL WIND SHIFT CURRENTLY DROPPING THROUGH THE AREA... WHICH WILL BE INTERACTING WITH AN AREA OF MLCAPE AOA 1500 J/KG. A SUBTLE SHORTWAVE FEATURE EVIDENT ON WATER VAPOR... AND APPARENT IN THE RAP 400-300MB PV ANALYSIS... IS CURRENTLY LIFTING NORTHEAST FROM EASTERN NEBRASKA... AND MAY HELP TO GET ACTIVITY GOING NEAR THE WIND SHIFT DURING THE LATE AFTERNOON OVER THE SOUTHERN AND SOUTHEAST PORTION OF THE FORECAST AREA. SO OVERALL... KEPT CHANCE POPS OVER THE ENTIRE AREA FOR THE REMAINDER OF THE AFTERNOON... THEN TRANSITIONED CHANCES SOUTH AND EAST THROUGH THE EVENING. CHANCES FOR PCPN DEPART TO THE EAST OVERNIGHT TONIGHT AS THE SURFACE LOW AND FRONT CONTINUE TO PUSH EAST AND A WEAK SURFACE RIDGE MOVES INTO THE AREA. THE MAIN UPPER TROUGH DROPS TOWARD THE AREA TOMORROW... ALONG WITH A SECONDARY SURFACE WAVE AND COLD FRONTAL BOUNDARY. WITH THE MID-UPPER COLD POOL MOVING INTO THE AREA... TOGETHER WITH SOME LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SURFACE LOW AND FRONTAL BOUNDARY... WE SHOULD SEE SOME SCATTERED SHRA/TSRA DROP SOUTHEAST ACROSS MUCH OF THE AREA FROM LATE MORNING THROUGH THE AFTERNOON HOURS. THE BEST CHANCES WILL BE OVER THE NORTHERN AND NORTHEAST PART OF THE AREA... BUT CAN/T RULE OUT SOME SHRA/TSRA AS FAR SOUTH AS THE MINNESOTA RIVER VALLEY DURING THE AFTERNOON HOURS DEPENDING UPON THE DEGREE OF DESTABILIZATION WHICH OCCURS FARTHER SOUTH AWAY FROM THE HEART OF THE MID-LEVEL COLD POOL. ON THURSDAY NIGHT... SCATTERED SHOWERS SHOULD DIMINISH AROUND/AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING. BY FRIDAY... ANY RESIDUAL ACTIVITY SHOULD BE CONFINED TO WEST CENTRAL WI COUNTIES NORTH OF INTERSTATE 94... AND THE WARRANTED COVERAGE SHOULD ONLY BE 20 PERCENT. H85 TEMPS COOL TO AROUND +12C TO +13C ON FRIDAY... SO HIGHS IN THE MID 70S TO LOWER 80S RANGE APPEAR REASONABLE WITH SCT-BKN MID CLOUDS AROUND. DRY AND NEAR NORMAL TEMPERATURES ARE EXPECTED FOR FRIDAY NIGHT AND SATURDAY AFTER THE EXODUS OF THE TROUGH. SATURDAY NIGHT AND SUNDAY WILL ARRIVE WITH THE NEXT OPPORTUNITY FOR MEASURABLE PRECIPITATION... AS MULTIPLE WEAK SHORTWAVES TOP THE PLAINS MID LEVEL RIDGE. RELATIVELY LOW CONFIDENCE ON WHETHER FORCING ASSOCIATED WITH THE WAVES WILL BE SUFFICIENT TO OVERCOME DRY/WARM AIR AT MID LEVELS... SO 30-40 POPS ARE AS HIGH AS WE WILL GO FOR NOW. FOR MONDAY THROUGH WEDNESDAY... HIGHS FROM 85-90 ARE EXPECTED... ALONG WITH LOWS FROM THE MID 60S TO LOWER 70S. THE PROXIMITY OF THE RIDGE AND MEAN WESTERLY/NORTHWESTERLY FLOW WILL COMPLICATE THE PRECIPITATION FORECAST NEXT WEEK. HAVE OPTED TO GO DRY AT THIS POINT SINCE CONFIDENCE/PROBABILITY ARE LOW AT THIS TIME. && .AVIATION.../18Z TAF ISSUANCE/ SURFACE LOW IS CURRENTLY SITTING OVER THE FORECAST AREA AND DRIFTING SOUTHEAST. THERE IS A WIND SHIFT ALONG THE SURFACE LOW/TROUGH AXIS... ALTHOUGH THE TRUE COLD FRONT STILL LAGS UPSTREAM OVER THE DAKOTAS WHERE THE DEWPOINT GRADIENT CAN BE SEEN ALONG WITH A SECONDARY TROUGH. THIS MEANS SOME INSTABILITY LAGS THE BOUNDARY BY A BIT... AND THE UPPER WAVE IS ALSO STILL LOCATED UPSTREAM. SO... ALTHOUGH THIS INITIAL BOUNDARY IS PUSHING THROUGH AND BRINGING SOME CHANCE FOR PCPN... THERE IS THE POTENTIAL FOR REDEVELOPMENT LATER THIS AFTERNOON AND EVENING AS THE UPPER WAVE AND FRONTAL BOUNDARY WORK INTO THE AREA. HOWEVER... AT THIS POINT MOST OF THE GUIDANCE SUGGESTS THINGS WILL COALESCE BEST JUST SOUTHEAST OF MOST OF THE TAF SITES... WITH PERHAPS KEAU HAVING THE BEST CHANCE OF SEEING ANY BONAFIDE ACTIVITY. WILL BEAR WATCHING... AND AMENDMENTS WILL CERTAINLY BE POSSIBLE. OTHERWISE... VFR CONDITIONS WILL PREDOMINATE AND WINDS WILL BE SHIFTING AROUND TO THE NORTHWEST THIS AFTERNOON INTO THE EVENING FROM WEST TO EAST. KMSP... PRIMARY UNCERTAINTY IN TAFS IS WITH CHANCES FOR SHRA/TSRA THIS AFTERNOON. PLAYED THINGS CONSERVATIVELY FOR NOW... BUT AMENDMENTS MAY BE NEEDED SHOULD SHRA/TSRA REDEVELOP NEAR/UPSTREAM OF KMSP RATHER THAN THE ANTICIPATED DOWNSTREAM. //OUTLOOK FOR KMSP FOR THURSDAY NIGHT THROUGH MONDAY THURSDAY NIGHT...SHRA AND MVFR CEILINGS AND VISIBILITIES POSSIBLE. FRIDAY...MVFR CEILINGS POSSIBLE EARLY. FRIDAY NIGHT THROUGH SATURDAY...VFR EXPECTED. SATURDAY NIGHT THROUGH SUNDAY...BRIEF MVFR CEILINGS VISIBILITIES POSSIBLE WITH SHRA/TSRA. SUNDAY NIGHT AND MONDAY...VFR EXPECTED. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ LRS/TRH
AREA FORECAST DISCUSSION
NWS DULUTH MN
1230 PM CDT WED JUL 25 2012 .AVIATION...18Z TAFS LOW PRESSURE IN SOUTH CENTRAL MINNESOTA WILL MOVE EAST THIS AFTERNOON...AS AN UPPER LEVEL TROUGH DIVES TOWARD NORTHERN MINNESOTA REACHING THAT AREA THURSDAY MORNING. A MIXTURE OF IFR TO VFR CEILINGS COVERED THE NORTHLAND...AND WE EXPECT MOST AREAS TO REMAIN OR BECOME MVFR AS ANY CLEAR AREAS FILL IN WITH CUMULUS. A FEW SHOWERS WILL ALSO BE POSSIBLE...BUT COVERAGE WILL BE LIMITED. A BETTER CHANCE FOR SHOWERS AND STORMS WILL OCCUR THIS EVENING...MAINLY OVER WESTERN AREAS. THIS AREA WILL MOVE EAST OVERNIGHT AS THE TROUGH MOVES CLOSER. WE LIMITED THE MENTION OF PRECIP THIS EVENING/OVERNIGHT TO THE KINL/KBRD/KHIB TAFS ATTM. AMENDMENTS OR LATER FORECASTS MAY ADD TO THE OTHER TAFS. FOG WILL ALSO BE AN ISSUE TONIGHT AS PLENTY OF LOW LEVEL MOISTURE COVERS THE AREA. WE PUT VSBYS THE LOWEST AT KDLH WHICH WILL SEE LIGHT ONSHORE WINDS TONIGHT. && .PREV DISCUSSION... /ISSUED 948 AM CDT WED JUL 25 2012/ UPDATE... NOW THAT MUCH OF THE RAIN HAS MOVED OUT OF THE EASTERN FA WITH THE LOW PRESSURE SYSTEM MOVING THROUGH THE MINNESOTA AND WESTERN LAKE SUPERIOR REGION...UPDATED THE GRIDS THROUGH THIS EVENING. THINK THE LINGERING RAIN AND THUNDER WILL CONTINUE TO MOVE OUT OF THE EASTERN FA THIS MORNING...AND ANOTHER CLUSTER OF RAIN AND THUNDER IN CENTRAL MN WILL MOVE ACROSS THE SOUTHERN FA THIS MORNING AS IT FALLS APART. THIS IS SUPPORTED BY RECENT HRRR AND NAM MODEL RUNS. THEN FOR THIS AFTERNOON...THERE ARE TWO MAIN AREAS WHERE THERE MAY BE REDEVELOPMENT OF STORMS. THE NAM/WRF/HRRR ARE IN FAIRLY GOOD AGREEMENT THAT THERE MAY BE REDEVELOPING STORMS NEAR OR JUST SOUTHEAST OF THE SOUTHEASTERN FA THIS AFTERNOON NEAR THE COLD FRONT MOVING THROUGH THE REGION. ALSO...THERE MAY BE STORMS LATE THIS AFTERNOON OR THIS EVENING IN THE WESTERN FA NEAR THE SECONDARY COLD FRONT ASSOCIATED WITH THE POTENT SHORTWAVE COMING OUT OF CANADA. BOTH AREAS COULD SEE SOME STRONG...MAYBE SEVERE...THUNDERSTORMS DUE TO ADEQUATE INSTABILITY AND SHEAR. KEPT LOW CHANCES OF PCP FOR THE REST OF THE FA THROUGH THIS EVENING TO ACCOUNT FOR ANY MARGINS OF ERROR. && PREV DISCUSSION... /ISSUED 358 AM CDT WED JUL 25 2012/ SHORT TERM...LATEST REGIONAL RADAR MOSAIC SHOWS WIDESPREAD SHOWERS AND STORMS OVERSPREADING OUR MN ZONES EARLY THIS MORNING...WITH SC TD SHOWERS AND STORMS ACROSS OUR WI ZONES. THIS ACTIVITY IS ASSOCIATED WITH A FAIRLY STRONG SHORTWAVE PROPAGATING WED ACROSS THE MIDWEST EARLY THIS MORNING. WITH MUCAPE VALUES RANGING FROM 1000-3000 J/KG AND SRH VALUES RANGING FROM 200 TO 400 M2/S2 ACROSS THE REGION...INITIALLY THE CONVECTION WAS QUITE ORGANIZED ACROSS WRN MN RESULTING IN ISOLD SVR STORMS. CURRENTLY THE STRENGTH OF THE CONVECTION HAS WEAKENED WITH HEAVY RAIN BEING THE MAIN CONCERN AS IT SPREADS EAST ACROSS OUR CWA. THE LATEST SPC RUC ANALYSIS SHOWS PWAT VALUES RANGING FROM 1.5 TO 2 INCHES ACROSS MOST OF THE CWA. HOWEVER WITH THE FLOW ALOFT BEING FAIRLY PROGRESSIVE...THE RAIN SHOULD TAPER OFF FROM THE WEST BY THIS AFTERNOON...AND END ACROSS OUR SERN ZONES THIS EVENING. EVEN SO...WE WILL KEEP THE FF WATCH IN EFFECT FOR THE NORTHSHORE DUE TO PREVIOUS FLOOD DAMAGE FROM A MONTH AGO AND FAST REACTING STREAMS/CREEKS THE NORTHSHORE. A RESPITE IN THE PRECIPITATION IS EXPECTED FOR TONIGHT BEFORE A POTENT UPPER TROUGH OVER SRN CANADA IS PROGGED TO DIG SEWD OVER THE NORTHLAND ON THURSDAY. THE SECOND ROUND OF SHOWERS AND STORMS SHOULD BE FAIRLY WIDESPREAD...BUT NOT AS STRONG OR HEAVY. TEMPERATURES TODAY SHOULD BE SEASONABLY WARM IF THERE ARE SOME BREAKS IN THE RAIN AND CLOUD COVER. HOWEVER WITH THE UPPER TROUGH OVER THE WRN GREAT LAKES TOMORROW...TEMPS WILL BE SEASONABLY COOL WITH HIGHS ONLY IN THE LOWER TO MID 70S FOR MOST LOCATIONS. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. A SHORTWAVE WILL CONTINUE TO MOVE THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY...WITH SOME LINGERING SHOWERS AND THUNDERSTORMS. WE WILL CONTINUE IN A GENERAL NW FLOW PATTERN FROM LATE IN THE WEEK INTO THE WEEKEND. IN GENERAL...THERE WILL CONTINUE TO BE A CHANCE OF SHOWERS AND THUNDERSTORMS FOR MOST OF THE PERIODS DURING THE EXTENDED TIME FRAME. TEMPERATURES WILL CONTINUE TO BE QUITE WARM...WITH 80S TO LOWER 90S THROUGHOUT THE PERIOD. NOT REALLY A LOT OF FEATURES THROUGHOUT THE EXTENDED PERIOD...SO MAINLY LOOKING AT SOME DIURNAL PRECIPITATION DUE TO SUBTLE FEATURES. && .POINT TEMPS/POPS... DLH 59 73 57 76 / 20 70 50 30 INL 56 72 55 78 / 40 70 40 10 BRD 62 77 59 78 / 20 50 20 10 HYR 59 78 58 77 / 20 60 50 20 ASX 59 76 59 74 / 20 60 50 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
313 PM CDT WED JUL 25 2012 .DISCUSSION... THUNDERSTORMS TONIGHT...THEN SOMEWHAT COOLER TEMPERATURES AND SPORADIC PRECIP CHANCES THROUGH THE WEEKEND...ARE THE PRIMARY FORECAST CONCERNS. COOL FRONT WAS DRIFTING SOUTHEAST THROUGH THE CWA THIS AFTERNOON...AND HAD JUST SLIPPED PAST A COLUMBUS TO TEKAMAH LINE AS OF 2 PM. PLUME OF MID LEVEL MOISTURE ACROSS WESTERN INTO NORTH CENTRAL NEBRASKA NOTED ON WATER VAPOR IMAGERY WAS SHIFTING EAST OVER THE FRONTAL BOUNDARY. SCATTERED SHOWERS AND STORMS WERE FIRING UNDER THIS PLUME...AFFECTING MUCH OF CENTRAL NEBRASKA AND WERE TRYING TO SNEAK INTO OUR NORTHWESTERN CWA. SURFACE-BASED CAPE VALUES WERE TOPPING 2000 J/KG ALONG FRONTAL BOUNDARY THIS AFTERNOON...BUT SIGNIFICANT CINH WAS ALSO NOTED. SOMEWHAT LESS UNSTABLE AIR WAS NOTED USING MIXED-LAYER CAPE WHERE VALUES WERE BETWEEN 1000 AND 1500 J/KG. EFFECTIVE AND BULK SHEAR WERE BOTH WEAK GIVEN RELATIVELY LIGHT MID LEVEL FLOW. SO ORGANIZED SURFACE-BASED STORMS DO NOT APPEAR LIKELY THIS EVENING. HOWEVER STEEP MID LEVEL LAPSE RATES SHOULD ALLOW FOR QUICK VERTICAL DEVELOPMENT OF ANY CONVECTION THAT FIRES IN OUR CWA...THEN COLLAPSING OF THOSE STORMS COULD PRODUCE STRONG TO SEVERE WIND GUSTS WITH TEMPERATURE/DEW POINT SPREADS APPROACHING 40F. DOWNDRAFT CAPE OF 1800 J/KG WAS ALSO MAXIMIZED ALONG FRONTAL BOUNDARY. GIVEN SHOWERS AND STORMS WERE ALREADY FIRING AND APPROACHING THE CWA...COMBINED WITH ALL SHORT-RANGE MODEL OUTPUT SUGGESTING PRECIPITATION NEAR AND BEHIND FRONTAL BOUNDARY...WILL INCREASE POPS ACROSS MOST OF THE CWA FOR THIS EVENING. 15-16Z HRRR SEEMS TO HAVE A DECENT HANDLE ON CURRENT PRECIPITATION...AND FIRES CONVECTION ALONG FRONTAL BOUNDARY AS IT SINKS FARTHER SOUTHEAST INTO THE CWA. MODELS ALSO SHOW POST-FRONTAL PRECIPITATION CONTINUING THROUGH THE NIGHT AIDED BY RIGHT ENTRANCE REGION OF MID LEVEL JET...THOUGH COVERAGE WILL CERTAINLY WANE AS WE GO PAST MIDNIGHT. SOME LINGERING SHOWERS/STORMS COULD AFFECT OUR FAR SOUTHEAST CWA THURSDAY MORNING...BUT THAT SHOULD EXIT QUICKLY. THEN NORTHWEST LOW LEVEL FLOW AND SLOWLY COOLING 850 TEMPERATURES POINT TO CLOSER-TO-NORMAL TEMPERATURES THURSDAY AFTERNOON. GFS IS COOLER THAN NAM IN THIS REGARD. WILL CONTINUE WITH HIGHS IN THE LOWER 90S...WHICH IS RIGHT IN THE MIDDLE OF NAM/GFS MOS NUMBERS. ONE CAVEAT TO WATCH FOR IS DOWNSLOPING NORTHWEST FLOW PUSHING HIGHS A FEW DEGREES WARMER AS PER NAM. SURFACE HIGH WILL SETTLE ACROSS THE AREA THROUGH FRIDAY AFTERNOON WITH RETURN FLOW BEGINNING FRIDAY NIGHT. LOWS IN THE LOW TO MID 60S LOOK GOOD FOR FRIDAY MORNING...WITH HIGHS FRIDAY AFTERNOON RIGHT AT NORMAL IN THE UPPER 80S. GFS HAS ADVERTISED THE LAST FEW DAYS A MID LEVEL SHORTWAVE ROLLING INTO THE PLAINS FRIDAY NIGHT AND SATURDAY MORNING. OTHER MODELS HAVE COME IN LINE WITH THIS THINKING...SO CONFIDENCE IS GROWING ON PRECIP CHANCES THEN. EXPECT WARM ADVECTION ON MODERATE LOW LEVEL JET AHEAD OF WAVE TO FIRE CONVECTION AFTER MIDNIGHT IN NORTHEAST NEBRASKA...WITH THIS PRECIP TURNING SOUTHEAST DOWN THE RIVER BY MORNING. HAVE INCREASED POPS ACCORDINGLY...WITH HIGHEST CHANCES ALONG SOUTH DAKOTA BORDER AND THROUGH AREAS NORTH AND NORTHEAST OF OMAHA. A SECOND SHORTWAVE LOOKS TO ROLL THROUGH AGAIN SATURDAY NIGHT AND SUNDAY WITH SIMILAR WARM ADVECTION SIGNALS SUGGESTING CONVECTION WILL FIRE AGAIN. ECMWF IS MORE BULLISH ON FRIDAY NIGHT WAVE...AND PUSHES SATURDAY NIGHT PRECIP A BIT FARTHER TO THE NORTHEAST THAN GFS. LINGERING FRONTAL BOUNDARY BEHIND THIS SYSTEM WILL MOST LIKELY SET UP ACROSS OUR CWA FOR MONDAY...WHICH MAY FOCUS A FEW STORMS MONDAY AFTERNOON. SO WILL KEEP A SMALL POP GOING THEN. UPPER RIDGE WILL BEGIN BUILDING BACK INTO THE REGION BEYOND MONDAY...SO HAVE KEPT FORECAST DRY AND A BIT WARMER THEN. HAVE HIGHS IN THE UPPER 80S TO LOWER 90S SATURDAY...THEN LOWER 90S SUNDAY...BEFORE GRADUALLY INCREASING HIGHS TOWARD THE MID AND UPPER 90S BY WEDNESDAY. DERGAN && .AVIATION... 18Z TAFS FOR KOFK...KOMA AND KLNK. A COLD FRONT FROM NORTHEAST INTO SOUTH CENTRAL NEBRASKA AT 18Z WILL TRACK ACROSS THE AREA THIS AFTERNOON AND THIS EVENING. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE VICINITY OF THE FRONT THIS AFTERNOON AND CONTINUE INTO THE EVENING. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR NEZ044- 045-050>053-065>068-078-088>093. IA...EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR IAZ055- 056-069-079-080-090-091. && $$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
253 PM MDT WED JUL 25 2012 .DISCUSSION... ...POTENTIAL FOR LOCALLY HEAVY RAIN WILL CONTINUE THRU THE WEEKEND... AFTERNOON RADAR AND SATELLITE TRENDS ALIGNING VERY WELL WITH THE LATEST HIRES HRRR AND RUC13 MODELS...INCREASING CONFIDENCE THAT MAIN FOCUS FOR HEAVY RAINFALL WILL BE ALONG AND EAST OF THE CENTRAL MT CHAIN INTO THIS EVENING. PWAT VALUES PER CIRA IMAGERY ARE BTWN 1 AND 1.2 INCHES WHICH IS 100-125 PCT OF NORMAL. A WELL DEFINED VORT MAX NEARLY STATIONARY OVER THE EAST CENTRAL PLAINS WILL FOCUS WITH A BACK DOOR FRONT TO PRODUCE SCT TO NMRS STORMS THIS EVENING. DRIER STABLE AIR WILL QUICKLY DIMINISH MOST ACTIVITY FOR CENTRAL AND WESTERN AREAS BY MIDNIGHT. THE BACK DOOR FRONTAL BNDRY WILL SLIDE INTO THE RIO GRANDE VALLEY TMRW AFTERNOON AIDED BY CONVECTION ALONG THE EAST SLOPES. GAP WINDS ARE EXPECTED MOST AREAS. MAIN FOCUS OF THETA-E RIDGE AXIS WILL BE OVER MANY AREAS OF CENTRAL NM. PWAT VALUES CONTINUE TO RISE TO BTWN 1.2 AND 1.4 WHICH WILL POSE AND ELEVATED THREAT FOR FLASH FLOODING. STEERING FLOW WILL BE WEAKEST AND MOST CONVERGENT ALONG THE CONT DVD THEREFORE A WATCH IS POSSIBLE HOWEVER WILL DELAY TO FOLLOWING SHIFTS. HAVE RAISED POPS SLIGHTLY MORE TO COVER HIGHER CHANCES FOR THE CENTRAL VALLEYS. BY FRIDAY THE FOCUS SHIFTS TO THE WESTERN HALF OF THE STATE WHERE HEAVY RAINFALL POTENTIAL CONTINUES. PWATS ADVERTISED BTWN 1.2 AND 1.4 AGAIN WITH LOTS OF INSTABILITY. STEERING FLOW WILL BECOME MORE SW TO NE AND SPEED UP TO NEAR 15KTS SO WHILE HEAVY RAINFALL IS LIKELY THE POTENTIAL FOR FLASH FLOODING MAY BE LIMITED TO TRAINING CELLS. EXPECT ACTIVITY TO SLIDE NORTHEAST ON OUTFLOWS TOWARD THE RIO GRANDE VALLEY EACH EVENING IN THIS VERY MOIST STEERING PATTERN. MAX TEMPS WILL REMAIN VERY CLOSE TO SEASONAL NORMS WHILE MIN TEMPS REMAIN 5 TO 10F ABOVE NORMAL. GUYER && .FIRE WEATHER... AS ADVERTISED THE MAIN WETTING STORM FOCUS WILL SHIFT FROM THE WESTERN HALF LIKE WAS SEEN YESTERDAY TO THE EASTERN HALF TODAY. A BACK DOOR COLD FRONT HAS CUT INTO THE NORTHEAST PLAINS AND HAS CREATED ABUNDANT STORM COVERAGE ACROSS THE SANGRE DE CRISTOS. STORMS WILL TEND TO DRIFT OFF TO THE SOUTHEAST AND IMPACT THE EASTERN PLAINS TONIGHT. WITH THE BOUNDARY AROUND...LOOK FOR CONTINUED ABUNDANT RAINFALL ACROSS THE CENTRAL MOUNTAINS AND LARGE PORTIONS OF THE EASTERN PLAINS ON THURSDAY. MORE ISOLATED ACTIVITY WILL BE FOUND ACROSS THE WEST DURING THE NEXT 36 HOURS AS DRIER AIR FILTERS IN. LOOKING AT SOME TEEN HUMIDITIES ACROSS THE FOUR CORNERS AREA BY THURSDAY. HIGH TEMPERATURES WILL BE NEAR NORMAL ALTHOUGH PERHAPS A FEW DEGREES BELOW NORMAL ACROSS THE NORTHEAST ON THURSDAY. BACK DOOR FRONT WILL INFILTRATE THE RIO GRANDE VALLEY LATER TONIGHT BUT MAKE MORE OF A PUSH WESTWARD UNDERNEATH THE UPPER HIGH THURSDAY NIGHT INTO FRIDAY MORNING. THIS WILL PUSH THE FOCUS OF WETTING STORMS BACK TO THE WEST ON FRIDAY. ESPECIALLY FAVORING THE CONTINENTAL DIVIDE REGION AS DEPICTED BY THE GFS AND TO A LESSER EXTENT THE ECMWF AND NAM. THIS SHOULD BE THE REPLENISHMENT OF MOISTURE THAT IS NEEDED TO FUEL HIGHER COVERAGE OF WETTING STORMS ACROSS THE WESTERN HALF. IT APPEARS THAT A CONSOLIDATED UPPER HIGH...BOTH BERMUDA AND SUBTROPICAL...SHOULD BE FOUND OVER THE RED RIVER VALLEY BETWEEN TX AND OK DURING THE WEEKEND AND EARLY NEXT WEEK. MODELS ARE SHOWING A NICE MONSOONAL PLUME SIGNATURE OVER THE WESTERN THIRD TO HALF OF THE FORECAST AREA DURING THIS PERIOD...ESPECIALLY DURING THE WEEKEND TIME FRAME. PERHAPS SOME SUBSIDENCE/MID LVL DRY SLOT EFFECTS OVER THE EASTERN PLAINS ALTHOUGH STEERING FLOW BY EARLY NEXT WEEK COULD TAKE STORMS OFF THE CENTRAL MTNS INTO THE EASTERN PLAINS LATER IN THE DAY PERIOD. BOTH ECMWF AND GFS TREND THE UPPER HIGH CENTER BACK OVER THE STATE AS NEXT WEEK PROGRESSES. THIS WOULD ESSENTIALLY STEER THE MONSOONAL PLUME FURTHER WEST BUT COULD ALSO BRING ANOTHER BACK DOOR COLD FRONT INTO THE EQUATION. EITHER WAY...UNSETTLED WEATHER EXPECTED THROUGH THE NEXT SEVERAL DAYS WITH THE INITIAL FOCUS ACROSS THE EASTERN HALF BUT TRANSITIONING WESTERN HALF AS THE WEEK PROGRESSES INTO THE WEEKEND. 50 && .AVIATION... 18Z TAF CYCLE OVERALL...EXPECTING LESS TS AND SH ACTIVITY WESTERN AREAS VERSUS YESTERDAY AND ALREADY SEEING A SLOWER START TO THE DVLP. HOWEVER...EXPECTING MORE ACTIVE TS/SH CENTRAL MTNS EASTWARD...ESPECIALLY THE EASTERN PLAINS. A MODERATE BACK DOOR COLD FRONT WILL PROVIDE THE FOCUSING MECHANISM FOR THIS ACTIVITY IN THE EAST TODAY. THUS...HAVE GONE BULLISH WITH SOME SORT OF PRECIP MENTION AT LVS...TCC AND TO LESSER EXTENT ROW. BASED ON AN OVERALL NORTHERLY STEERING FLOW...CANT RULE OUT ABQ AND SAF AS WELL AS GUP. NOT EXPECTING SH/TS AFFECTS AT FMN. GUSTY OUTFLOW WINDS WILL BE THE MAIN IMPACT CENTRAL AND WESTERN TERMINAL SITES. THINKING THE POSSIBILITY OF MVFR CIG/VIS FOR SHORT DURATION POSSIBLE ACROSS THE EAST ALTHOUGH NOT REFLECTIVE IN THE TAF/S. WILL UPDATE ACCORDINGLY AS HEAVIER PRECIP STORMS DVLP. 50 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 62 93 64 92 / 10 20 30 30 DULCE........................... 49 89 49 85 / 20 30 40 40 CUBA............................ 54 86 55 83 / 20 30 40 40 GALLUP.......................... 54 88 55 85 / 20 20 30 40 EL MORRO........................ 52 84 51 80 / 20 30 40 50 GRANTS.......................... 54 87 54 83 / 20 30 40 40 QUEMADO......................... 56 85 56 82 / 40 40 40 50 GLENWOOD........................ 58 92 58 92 / 30 20 30 40 CHAMA........................... 48 83 50 80 / 30 40 50 50 LOS ALAMOS...................... 59 85 60 84 / 30 60 40 40 PECOS........................... 57 81 57 81 / 40 60 40 40 CERRO/QUESTA.................... 54 79 55 80 / 30 50 40 50 RED RIVER....................... 48 69 47 71 / 40 60 40 60 ANGEL FIRE...................... 44 72 45 73 / 40 60 40 60 TAOS............................ 51 86 49 86 / 30 40 40 40 MORA............................ 55 78 54 79 / 40 50 50 50 ESPANOLA........................ 59 92 58 91 / 30 40 30 30 SANTA FE........................ 60 83 60 82 / 40 50 40 40 SANTA FE AIRPORT................ 61 87 60 87 / 30 40 40 30 ALBUQUERQUE FOOTHILLS........... 64 90 65 88 / 30 40 50 40 ALBUQUERQUE HEIGHTS............. 65 91 68 89 / 30 30 40 30 ALBUQUERQUE VALLEY.............. 63 93 66 91 / 20 30 40 30 ALBUQUERQUE WEST MESA........... 67 93 66 90 / 20 30 40 30 LOS LUNAS....................... 63 92 64 91 / 20 30 40 30 RIO RANCHO...................... 67 92 67 90 / 20 30 40 30 SOCORRO......................... 66 94 67 94 / 20 30 40 30 SANDIA PARK/CEDAR CREST......... 61 84 61 84 / 30 60 50 50 TIJERAS......................... 59 88 61 88 / 30 50 50 40 MORIARTY/ESTANCIA............... 58 87 57 85 / 40 50 50 40 CLINES CORNERS.................. 57 83 58 82 / 40 60 50 50 GRAN QUIVIRA.................... 60 86 61 84 / 40 40 50 50 CARRIZOZO....................... 61 89 62 88 / 30 40 40 50 RUIDOSO......................... 59 80 58 77 / 40 50 50 50 CAPULIN......................... 59 80 60 83 / 50 60 30 30 RATON........................... 57 87 57 90 / 50 60 30 30 SPRINGER........................ 60 86 60 88 / 40 40 30 30 LAS VEGAS....................... 55 82 55 83 / 40 60 40 50 CLAYTON......................... 67 88 66 92 / 50 30 20 20 ROY............................. 65 85 64 85 / 50 40 30 20 CONCHAS......................... 69 93 69 94 / 50 40 30 30 SANTA ROSA...................... 70 93 69 91 / 40 40 40 30 TUCUMCARI....................... 70 95 72 96 / 40 40 40 30 CLOVIS.......................... 70 91 69 90 / 40 40 40 30 PORTALES........................ 72 93 70 92 / 40 40 40 30 FORT SUMNER..................... 74 93 72 93 / 40 40 40 30 ROSWELL......................... 70 96 71 93 / 40 40 30 30 PICACHO......................... 66 88 65 84 / 40 40 40 30 ELK............................. 60 83 59 79 / 40 40 50 40 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ GUYER
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
420 PM EDT WED JUL 25 2012 .SYNOPSIS... A STRONG WARM FRONT LIFTING THROUGH INDIANA AND KENTUCKY WILL CONTINUE NORTH AND EASTWARD TONIGHT ALLOWING VERY WARM AIR OVER THE CENTRAL MISSISSIPPI VALLEY TO SPREAD INTO THE AREA TONIGHT. THIS WARM FRONT MAY BE ACCOMPANIED BY A FEW THUNDERSTORMS DURING THE NIGHT AS IT CROSSES THE AREA...BUT THE BIGGER STORY WILL COME ON THURSDAY WHEN HEAT BUILDS AHEAD OF A COLD FRONT SAGGING INTO THE GREAT LAKES. HEAT INDICES IN EXCESS OF 100 DEGREES ARE LIKELY FOR MUCH OF THE AREA...AND AS THE FRONT ARRIVES AT PEAK HEATING...NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE AREA...SOME WHICH ARE LIKELY TO BE SEVERE. THE FRONT WILL CONTINUE A VERY SLOW PROGRESSION SOUTH AND EAST ON FRIDAY WITH LINGERING THREATS FOR STORMS...BEFORE PUSHING OUT OF THE AREA BY SATURDAY. THIS SHOULD BRING SLIGHTLY COOLER TEMPERATURES AND LESS HUMIDITY TO THE AREA FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... PLAN TO ALLOW EXCESSIVE HEAT WARNING AND HEAT ADVISORIES EXPIRE AS SCHEDULED AT 8 PM...EXCEPT FOR HAMILTON/MONTGOMERY COUNTIES WHERE WE WILL CONTINUE WITH HEAT HEADLINES THROUGH THE NIGHT DUE TO LOCAL EXCESSIVE HEAT WARNING CRITERIA. STRONG WARM FRONT CURRENTLY DRAPED NW-SE ACROSS INDIANA AND KENTUCKY TO CONTINUE TO PUSH EAST THIS EVENING AND HAS SUBSTANTIAL BOUNDARY LAYER MOISTURE POOLED ALONG THIS FEATURE VIA CONVERGENCE. DEW POINTS IN THE SULTRY MID 70S ALLOWING FOR THE EXCESSIVE HEAT WARNING THIS EVENING IN THE SOUTHWEST. A BIG AIRMASS CHANGE TO THAT OVER CNTL OH WHERE DEW POINTS STILL AROUND 60 WITH TEMPS ONLY IN THE 80S. CURRENTLY WATCHING DEVELOPING CUMULUS FIELD ALONG/BEHIND THE WARM FRONT WHERE HRRR RUNS HAVE BEEN CONSISTENT IN ADVERTISING SCT TO NUMEROUS STORMS BETWEEN 4 PM AND 8 PM ON THE FRONT...AND PUSHING EAST THROUGH THE WFO ILN FORECAST AREA. IF THIS OCCURS...THERE WILL BE A SEVERE THREAT GIVEN EXPLOSIVE CAPE IN EXCESS OF 3000 J/KG ALONG THE FRONT AND MARGINAL SUPERCELLULAR SHEAR AROUND 25-30KTS WHEN CONSIDERING DEEPER TROPOSPHERIC FLOW ALONG AND ON THE COOL SIDE OF THE WARM FRONT. HOWEVER...UNDER SHORTWAVE RIDGING AND NO APPARENT S/W ON WV IMAGERY...VERY LITTLE BACKGROUND/SYNOPTIC FORCING FOR ASCENT. FEELING IS CURRENTLY THAT WE WILL DEVELOP STORM OR TWO IN THE MOST CONVERGENT AREAS ALONG THE FRONT AS HEATING PUSHES TEMPS PAST 100 DEGREES TO OUR WEST AND CAP IS LOCALLY BROKEN. MAY HAVE AN ISOLD SVR THREAT ON OUR HANDS...BUT THIS IS CONDITIONAL AND BEST HANDLED BY THE GOING 25-35 PERCENT RAIN CHANCES CURRENTLY IN THE FORECAST. WITH CORE OF HIGHEST 925MB/850MB TEMPS COMING ACROSS FORECAST AREA OVERNIGHT...AND INCREASING SURFACE TO 1KM FLOW...FEEL MOS TEMPS WAY TOO LOW AND RUNNING ABOVE. WONDERING IF SOME AREAS /CVG/ MAY STRUGGLE TO DIP BELOW 80 GIVEN THE INCREASING MIXING AND WARM ADVECTION THROUGH THE NIGHT. THE THREAT FOR AN ELEVATED STORM WILL PROBABLY CONTINUE ALL NIGHT IN AN ISOLD FASHION VIA STRONG LOW LEVEL JET AND WARM ADVECTION. AGAIN...LACK OF CONVERGENCE OR S/W SHOULD KEEP ANY ACTIVITY RELATIVELY ISOLD. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... ATTENTION ON HEAT AND SEVERE WEATHER THREAT ON THURSDAY AFTERNOON AND EVENING...WITH HEAT THE LESSER OF THE TWO HAZARDS. REGARDING HEAT...AS MENTIONED ABOVE...CORE OF VERY WARM AIR ALOFT /850MB TEMPS TO +23C/ WILL BE PUSHING ACROSS AND THEN EAST OF THE AREA THROUGH THE MORNING YIELDING +20C/21C IN IT/S WAKE FOR THE AFTERNOON. GIVEN THE MIXED BOUNDARY LAYER RIGHT OFF THE BAT AT SUNRISE...TEMPS SHOULD RESPOND VERY QUICKLY TO SUNSHINE AND WARM QUICKLY INTO THE 90S BY LATE MORNING OR NOON. WHILE DEW POINTS WILL MIX OUT A LITTLE IN THE AFTERNOON AS THE WARM FRONT/MOISTURE POOLING PUSHES OUT OF THE AREA...DON/T ANTICIPATE TOO MUCH DROP OFF DURING THE DAY...AND EXPECT DEW POINTS 68-70 MUCH OF AFTERNOON DESPITE THE BREEZY CONDITIONS. THIS SHOULD PUSH HEAT INDICES TO AND ABOVE 100 DEGREES FOR THE AFTERNOON AND THUS HEAT ADVISORY ALL AREAS...WITH EXCESSIVE HEAT WARNING FOR HAMILTON/MONTGOMERY COUNTIES. BIG FOCUS THOUGH IS THE SEVERE WEATHER THREAT. THURSDAY AFTN HAS HAD AN ANALOG SIGNAL /CIPS EXPERIMENTAL WARM SEASON GUIDANCE/ OF A HIGHER END SEVERE THREAT FOR SEVERAL DAYS AND CONFIDENCE CONTINUES TO HONE IN THAT A REGIONAL SEVERE WEATHER OUTBREAK IS IN THE CARDS FOR PORTIONS OF THE OHIO VALLEY INCLUDING THE LOCAL FORECAST AREA. ATTENTION WILL BE ON THE ANOMALOUS /FOR LATE JULY/ SHORTWAVE TROUGH CURRENTLY NEAR LAKE WINNIPEG...DIGGING SOUTHEAST TOWARD NRN MN ON THURSDAY. SYNOPTICALLY...DEEP SYSTEMS MOVING THROUGH NRN MN IN THE WARM SEASON HAVE HIGH CORRELATION TO SIGNIFICANT WEATHER EVENTS IN THE OHIO VALLEY...AND THIS SETUP APPEARS TO FIT THAT PATTERN. AS THIS SYSTEM DIGS INTO NRN MN...LOW/MID LEVEL FLOW WILL BACK EVER SO SLIGHTLY AND MARKEDLY INCREASE...WITH MAINTENANCE OF A STRONG SWLY LLJ AS WLY MID LEVEL FLOW /35 TO 40KTS/ OVERSPREADS THAT LLJ AXIS IN THE AFTN. COLD FRONTAL STRUCTURE WILL GET A LITTLE BETTER ORGANIZED AND SAG INTO THE GREAT LAKES IN THE AFTN AS CONVERGENCE SLOWLY INCREASES. GIVEN THE AMPLE HEAT/INSTABILITY BUILDING IN THE WARM SECTOR OVER THE WFO ILN CWA...THE COMBINATION OF THE INCREASING CONVERGENCE AND MORE IMPORTANTLY THE ARRIVAL OF A MORE SUBTLE SHORTWAVE /CURRENTLY OVER KS/ SHOULD PROMOTE THE DEVELOPMENT OF NUMEROUS STORM CLUSTERS WHICH MAY CONGEAL INTO A LONG /SPATIALLY/ CONVECTIVE SYSTEM WITH /GIVEN CAPE AND SHEAR PARAMETER SPACE/ AN ABOVE NORMAL CHANCE TO BE A LONGER LIVED/HIGHER END SEVERE WEATHER MCS. CIPS ANALOG GUIDANCE USING TOP 8 SVR ANALOGS TO THURSDAY AFTN VIA THE SPC PPF SYSTEM IS VERY MUCH DIALED IN ON IND/OH/PA AREA AS TARGET FOR VERY HIGH PROBABILITIES OF SEVERE WEATHER...AND HAS BEEN FOR SEVERAL DAYS...THIS IS NOT A ONE-RUN-AND-DONE SIGNAL. NEW SPC SWODY2 MIRRORS THIS THREAT AREA...ALBEIT SHIFTED A TAD SOUTH WHICH FITS HIGHER RESOLUTION /CONVECTION ALLOWING/ 4KM GUIDANCE. LATEST 27.12Z NCEP ARW-CORE HIRES WINDOW RUN IS ESPECIALLY MENACING...WITH A NRN LINEAR CONVECTIVE SYSTEM HITTING CNTL OHIO IN THE AFTN TO BE FOLLOWED AN INTENSE BOW ECHO DURING THE EVENING HITTING THE REST OF THE FORECAST AREA. A WIDESPREAD AND SIGNIFICANT SEVERE EVENT...WHICH ALSO MIRRORS NCEP NMM /SPC/ WRF. ADDING FURTHER CONFIDENCE...IS CALIBRATED SPC SREF SEVERE PROBABILITIES /NOT BASED ON ANALOGS/ THAT ALSO MIRRORS THE ANALOG AXIS AND CURRENT SPC FORECASTS. SO CONFIDENCE IS THERE...AND CONTINUED SEVERE MENTIONS IN FORECAST AND RAMPED UP WORDING IN HWO FOR IMPACTS OF POTENTIAL WIDESPREAD TREE DAMAGE AND SUBSEQUENT POWER OUTAGES. IF THE DUAL-MCS SOLUTION VERIFIES...THREAT FOR LOCALIZED FLOODING VIA THIS 1-2 PUNCH WILL BE INCREASED. NOT TO PILE IT ON...BUT THE TORNADO THREAT IS NON-ZERO AS WELL...AND DESPITE MOSTLY SWLY FLOW IN THE BOUNDARY LAYER...THERE IS DECENT TURNING IN THE LOWEST 1-2KM...SO THERE/S AN OUTSIDE THREAT OF A TORNADO OR TWO AS LOW LEVEL SHEAR APPEARS STRONG ENOUGH...AND WILL BE AUGMENTED IF WED NIGHT MCS ACROSS WISC/MICH CAN SEND A STRONG ENOUGH OUTFLOW BOUNDARY INTO CNTL OHIO BY MORNING/AFTN. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... FRIDAY FORECAST IS TRICKY AS DISJOINTED FRONTAL ZONE LAYS ACROSS THE OHIO VALLEY. PRESSURE TROUGH/BAROCLINIC ZONE/MOISTURE GRADIENT ARE ALL SOMEWHAT DISPLACED...AND WITH POTENTIAL FOR AN UPPER LEVEL SHORTWAVE TROUGH TO CROSS THE AREA...THERE WILL REMAIN THE RISK FOR THUNDERSTORM DEVELOPMENT. MODEL QPF FRIDAY MORNING SEEMS TIED TO WHATEVER DEVELOPS THURSDAY AFTERNOON...SO NOT SURE IF THESE POPS WILL PLAY OUT AS ADVERTISED ACROSS THE SOUTH. I EVENTUALLY SPREAD CHANCE POPS BACK ACROSS THE AREA BY AFTERNOON...HIGHEST IN THE EAST WHERE SIGNALS ARE BETTER. 12Z NAM SEEMS OVERDONE COMPARED TO OTHER MODELS IN REINTRODUCING A HOT/HUMID SURGE (AND ENSUING INSTBY) AHEAD OF THE COLD FRONT...SO WENT CLOSER TO A SREF/ECMWF BLEND. NEVERTHELESS...RESPECTABLE MID LEVEL FLOW COMBINED WITH THE INSTBY WILL MEAN THAT ANY STORMS THAT DO DEVELOP COULD BECOME SEVERE...WITH HIGHEST CHANCES IN THE EAST. FOR SATURDAY THROUGH MONDAY...MODELS AND ENSEMBLES AT LEAST AGREE ON THE UPPER LEVEL PATTERN...WITH REGION SITUATED ON EASTERN SIDE OF PLAINS/ROCKIES RIDGE. FOR SATURDAY...ADVANCING COLD FRONT MAY HANG UP ALONG THE APPALACHIANS...WITH A DISTURBANCE IN THE NORTHWEST FLOW ALOFT ACTIVATING CONVECTION ALONG IT. THERE ARE AT LEAST SOME INDICATIONS A SFC WAVE WILL BEND BACK INTO THE UPPER OHIO VALLEY...SO INCLUDED 20 POPS IN THE EASTERN CWA FOR SATURDAY AFTERNOON. WITH CAA OVER THE CWA...HIGHS WILL BE AT OR BELOW SEASONAL NORMALS. SUNDAY IS PROBABLY THE DAY WITH HIGHEST FORECAST CONFIDENCE AS SFC HIGH PRESSURE BUILDS OVER THE CWA. TEMPERATURES WILL BE SEASONABLE WITH FAIRLY LOW HUMIDITY. THE GFS/NCEP MODELS TAKES A MORE AMPLIFIED TURN BEGINNING MONDAY...WITH 500 MB HEIGHTS AT ILN RESIDING ON THE LOW END OF NAEFS SPREAD BY MID WEEK. THIS AFFECTS PCPN FORECASTS MORE THAN TEMPERATURES HOWEVER OVER THE LOCAL AREA (AS 00Z AND 12Z ECMWF HOLD A STRONGER SFC RIDGE IN PLACE). TOOK AN ENSEMBLE APPROACH WITH THE FORECAST...WHICH DID NOT SIGNIFICANTLY CHANGE THE GOING FORECAST. TUESDAY WILL HAVE THE HIGHEST PCPN CHANCES...SUPPORTED BY ENSEMBLES...AS WELL AS A SFC BDY/UPPER WAVE THAT MAY SAG DOWN INTO THE AREA. CANNOT TOTALLY RULE OUT PCPN MONDAY/WEDNESDAY BUT LIMITED TO 20 POPS. TEMPERATURES WILL RISE SOME AS LOW LEVEL FLOW BECOME MORE SOUTHERLY...BUT AT THIS TIME LOOK TO REMAIN WITHIN 5 DEGREES OF NORMAL. HUMIDITY WILL ALSO INCREASE SLIGHTLY...HOLDING UP OVERNIGHT LOWS. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... MID LEVEL RIDGE AXIS WILL PUSH EAST ACROSS THE OHIO VALLEY THROUGH TONIGHT. THIS WILL ALLOW A SURFACE WARM FRONT TO MOVE NORTHEAST THROUGH THE REGION. ALTHOUGH DECENT INSTABILITY AND SOME SHEAR WILL ACCOMPANY THIS FRONT LATE THIS AFTERNOON AND EVENING...FORCING IS NOT THAT SUBSTANTIAL. AS A RESULT...THINK CHANCES FOR SHOWERS AND STORMS WILL BE AROUND 30 PERCENT. HAVE DELAYED THE ONSET OF VCTS AT KDAY...KILN...KCVG AND KLUK TO BETWEEN 21Z AND 22Z. BELIEVE ACTIVITY WILL WANE THIS EVENING WITH THE LOSS OF DAYTIME HEATING. IT IS UNCLEAR WHETHER ANY CONVECTION WILL MAKE IT TO CENTRAL OHIO SO HAVE KEPT KCMH AND KLCK DRY. FOR LATE TONIGHT ONLY SOME SCATTERED CIRRUS OR HIGH LEVEL AC ARE EXPECTED. THURSDAY IS LOOKING TO BE AN INTERESTING DAY. MID/UPPER LVL FLOW BACKS TO THE WEST/SOUTHWEST. AT THE SURFACE...A COLD FRONT IS FORECAST TO SAG SE INTO THE NRN CWFA BY THURSDAY EVENING. AN EMBEDDED DISTURBANCE IS FORECAST TO MOVE WITHIN THE MID/UPPER LEVEL FLOW...PASSING ACROSS THE REGION BETWEEN 18Z AND 00Z. A DECENT LOW LEVEL JET AHEAD OF THE FRONT...DECENT MID LVL JET AROUND 50 KNOTS...AND AMPLE INSTABILITY WILL LIKELY RESULT IN A CONVECTIVE LINE OF SHOWERS AND THUNDERSTORMS. THE POTENTIAL EXISTS FOR THESE STORMS TO CONTAIN DAMAGING WINDS...ALTHOUGH LARGE HAIL AND SOME LOCALLY HEAVY RAIN CAN NOT BE RULED OUT. BEST CHANCE FOR DEVELOPMENT AND MAINTENANCE FROM WEST TO EAST ACROSS THE REGION WILL BE BETWEEN 18Z AND 00Z. FRONTAL BOUNDARY IS FORECAST TO STALL OUT ACROSS THE NRN FORECAST AREA THURSDAY NIGHT AS MID LVL FLOW TEMPORARILY BECOMES PARALLEL TO THE FRONTAL BOUNDARY. SOME MODELS ARE INDICTING THAT A WEST/SOUTHWEST ORIENTED LOW LEVEL JET MAY KEEP CONVECTION GOING IN THE FORM OF CLUSTERS...MAINLY ACRS SRN PARTS OF THE AREA...THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. THE PRESSURE GRADIENT AT THE SURFACE IS EXPECTED TO INCREASE TONIGHT AND THURSDAY AS SURFACE LOW PRESSURE RIPPLES ACROSS THE NORTHERN GREAT LAKES. THIS WILL RESULT IN BREEZY SOUTHWEST WINDS WITH GUSTS UP TO 30 KNOTS POSSIBLE THURSDAY OUTSIDE OF CONVECTION. OUTLOOK...THUNDERSTORMS POSSIBLE THURSDAY NIGHT INTO FRIDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ034-042-060- 061-070>072-078>081. HEAT ADVISORY FROM NOON TO 8 PM EDT THURSDAY FOR OHZ026-034- 035-042>046-051>056-060-062>065-070>074-078>082-088. EXCESSIVE HEAT WARNING FROM 8 PM THIS EVENING TO 8 PM EDT THURSDAY FOR OHZ061. EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THURSDAY FOR OHZ077. KY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR KYZ097>100. HEAT ADVISORY FROM NOON TO 8 PM EDT THURSDAY FOR KYZ089>100. EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR KYZ089>096. IN...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ050-058-059. HEAT ADVISORY FROM NOON TO 8 PM EDT THURSDAY FOR INZ050-058- 059-066-073>075-080. EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR INZ066- 073>075-080. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU SHORT TERM...BINAU LONG TERM...SNYDER AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
435 PM EDT WED JUL 25 2012 .SYNOPSIS... A WEAK UPPER LEVEL RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE REGION TONIGHT THROUGH THURSDAY BRINGING VERY WARM AND MUGGY CONDITIONS. A COLD FRONT IS EXPECTED TO MOVE ACROSS THE CAROLINAS AND NORTHEAST GEORGIA LATE FRIDAY AND INTO SATURDAY. ANOTHER RIDGE OF HIGH PRESSURE BUILDS BACK IN SUNDAY AND REMAINS THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/... AS OF 430 PM...CONVECTION FINALLY TAKING OFF ACROSS NC WITH SCT COVERAGE THERE AND ISOLATED OVER THE UPSTATE. EXPECT SCT COVERAGE ALL AREAS FOR THE REST OF THE AFTERNOON...WITH SLIGHTLY BETTER COVERAGE OVER THE NC PIEDMONT. STORMS BECOME ISOLATED ACROSS THE MTNS BY EARLY EVENING...THEN TAPER OFF FROM NORTH TO SOUTH BY MIDNIGHT. OTHERWISE...MAIN ADJUSTMENTS WERE FOR CURRENT CONDITIONS. SO FAR THE WORKED-OVER AIRMASS BEHIND THIS MORNING/S MCS HAS NOT SPAWNED ANY NEW CONVECTION. HOWEVER...THE CU FIELD IS BECOMING BETTER DEFINED AND RAP SOUNDINGS SHOW VERY HIGH SURFACE-BASED CAPE VALUES...PARTICULARLY ALONG AND JUST EAST OF THE BLUE RIDGE. THEREFORE IT SHOULDN/T BE TOO MUCH LONGER BEFORE CONVECTION BEGINS TO DEVELOP OVER THE HIGH TERRAIN. THE DEEP LAYER SHEAR IS ABOUT 20 KTS FROM THE NORTHEAST...AND ANY CELLS THAT DO DEVELOP SHOULD DRIFT INTO THE FOOTHILLS AND POSSIBLY THE WESTERN PIEDMONT. THE WRF-ARW AND 4KM SPC WRF-NMM ARE BOTH ALREADY WAY OVERDONE WITH CONVECTION OVER THE REGION...THOUGH THEY DO INSIST THAT VIGOROUS DEVELOPMENT WILL OCCUR. THE BOTTOM LINE IS THAT I/LL CONTINUE TO CARRY CHANCE POPS THE REST OF THE AFTN AND EVENING HOURS...WITH THE HIGHEST POPS ACROSS THE MTNS AND THE LOWEST ACROSS THE PIEDMONT. HOWEVER...WITH SUCH AN UNSTABLE ATMOSPHERE AND SEVERAL WEAK BNDRY/S OVER THE REGION IT/S ENTIRELY POSSIBLE THAT SCATTERED STORMS...ONCE THEY FORM...WILL WORK SOUTHEASTWARD ACROSS MUCH OF THE REGION DURING THE EVENING HOURS. A FEW SEVERE STORMS ARE A GOOD BET ONCE THEY START TO FIRE. THE ATMOSPHERE WILL WARM UP CONSIDERABLY TOMORROW AS THE CENTER OF A HOT DEEP LAYER RIDGE MOVES ACROSS THE REGION. HEAT INDEX VALUES SHOULD RISE INTO THE HEAT ADVISORY CRITERIA RANGE FOR SEVERAL HOURS IN THE AFTERNOON ACROSS THE CHARLOTTE METRO AREA...THE SOUTHERN UPSTATE AND IN ELBERT COUNTY GEORGIA. CLOSER TO THE MOUNTAINS DEWPOINTS ARE EXPECTED TO MIX OUT ENOUGH IN THE AFTERNOON TO KEEP THE HEAT INDEX BELOW ADVISORY CRITERIA. WITH WARMING MID LEVEL TEMPS...VERY LITTLE SHEAR AND DEWPOINTS MIXING OUT DURING THE AFTN...CONVECTION IS EXPECTED TO BE ISOLATED AND MAINLY CONFINED TO THE MOUNTAINS. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... AS OF 230 PM EDT WEDNESDAY...ON FRIDAY...A COLD FRONT WITH ACTIVE PRE-FRONTAL CONVECTION IS EXPECTED OVER MIDDLE KY/TN DURING THE PRE DAWN HOURS. THE FRONT AND PRE-FRONTAL TROF WILL APPROACH THE SOUTHERN APPALACHIAN REGION DURING THE MORNING AS A L/W TROF DEEPENS OVER THE MID WEST. CONVECTION IS EXPECTED OVER THE MTNS BY MID DAY...PUSHING EAST OF THE MTNS DURING THE AFTERNOON AND EVENING. THE ENVIRONMENT AHEAD OF THE CONVECTIVE BAND WILL FEATURE LLVL BULK SHEAR VALUES APPROACHING 20 KTS WITH CAPE RANGING FROM 1500 TO 2000 J/KG. A FEW ORGANIZED STORM CLUSTERS MAY DEVELOP ALONG AND AHEAD OF THE FRONT...POSSIBLY YIELDING DAMAGING WINDS AND HAIL. THE LATE DAY PASSAGE OF CONVECTION SHOULD ALLOW HIGH TEMPERATURES TO REACH THE U90S EAST OF THE MTNS. RETURN FLOW AHEAD OF THE FRONT WILL SUPPORT DEWPOINT VALUES IN THE U60S. THE COMBINATION OF THE HOT TEMPERATURES AND MODERATE HUMIDITY SHOULD YIELD HEAT INDEX VALUES ALONG AND EAST OF I-85 TO REACH NEAR 105 DURING THE LATE AFTERNOON. HEAT ADVISORY CRITERIA MAY BE REACHED EAST OF I-85. ON SATURDAY...THE CWA SHOULD REMAIN LARGELY IN A POST FRONTAL ENVIRONMENT...WITH NW LLVL WINDS. DOWNSLOPE FLOW AND LINGERING MILD THICKNESSES WILL SUPPORT HIGHS IN THE U80S ACROSS THE MTN VALLEYS AND MID 90S ALONG AND EAST OF I-85. DEWPOINTS MAY ALSO DECREASE A FEW DEGREES IN THE WAKE OF THE FRONT. FORECAST SOUNDINGS CONTINUE TO SHOWS CAPE VALUES AROUND 2000 J/KG DURING THE AFTERNOON. HOWEVER...A SHALLOW LAYER OF CIN MAY EXIST BELOW THE LFC AND AND AN WEAK INVERSION WITHIN THE MID LEVEL MAY LIMIT DEEP CONVECTION. GIVEN THE INSTABILITY AND THE PASSAGE OF THE MID LEVEL TROF I WILL ADVERTISE SCHC POPS DURING THE AFTERNOON. IF CONVECTION DOES DEVELOP...THETA-E LAPSE RATES IN THE MID 30S COULD SUPPORT A DAMAGING WET MICROBURST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 200 PM EDT WEDNESDAY...THE LATEST MODELS CONTINUE TO INDICATE THAT THE UPPER TROUGH PERSISTS OVER THE EASTERN CONUS AND A BROAD UPPER LEVEL RIDGE OF HIGH PRESSURE REMAIN IN PLACE OVER THE GREAT PLAINS THROUGH THE EXTENDED FORECAST PERIOD. AT THE SURFACE...A FAIRLY STRONG HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE REGION FROM THE NORTH BY LATE SATURDAY AND REMAINS THROUGH SUNDAY FOR MOSTLY DRY WEATHER WITH SEASONABLY WARM TEMPERATURES. AS THE HIGH MOVES OFF TO THE EAST MONDAY...A SURFACE LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE CAROLINAS AND LINGERS INTO WEDNESDAY. THIS WILL RESULT IN UNSETTLED WEATHER PATTERN AND COOLER TEMPERATURES ACROSS MUCH OF OUR CWA. TEMPERATURES WILL REMAIN NEAR...OR A COUPLE DEGREES ABOVE NORMAL THROUGH TUESDAY WITH AFTERNOON HIGHS IN THE LOW 90S OVER THE PIEDMONT. TEMPERATURES WILL DROP 5-10 DEGREES BY WEDNESDAY WITH HIGHS IN THE MID 80S OVER THE PIEDMONT AND 70S MTNS. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... AT KCLT...CONVECTION NEARING THE AIRFIELD SO WILL AMD WITH TEMPO TSRA. WILL UPDATE WIND FOR CURRENT CONDITIONS...OTHERWISE NO CHANGES TO LATER PERIODS. NOT LOOKING FOR ANY SIGNIFICANT SIG OR VSBY RESTRICTIONS OVERNIGHT...THOUGH A PERIOD OF MVFR FOG IS POSSIBLE. WINDS WILL BE LIGHT OVERNIGHT...INCREASING TO AROUND 10 KTS FROM THE SOUTHWEST THU AFTN. AND ELSEWHERE...SCT TSTMS DEVELOPING OVER THE MTNS WILL DRIFT SOUTH AND DEVELOP OVER THE UPSTATE THRU THE REST OF THE AFTERNOON AND EARLY EVENING. THIS HAS BEEN ACCOUNTED FOR WITH A VCTS AT MOST AIRFIELDS. OTHERWISE WINDS WILL BE MAINLY OUT OF THE SW THIS AFTN...LIGHT TONIGHT...AND INCREASING TO AROUND 10 KTS FROM THE SW ON THURSDAY. IT WILL BE QUITE HOT TOMORROW...BUT THERE DOESN/T APPEAR THAT THERE WILL BE MUCH THUNDERSTORM ACTIVITY AS A STRONG RIDGE BUILDS ACROSS THE REGION. OUTLOOK...CHANCE FOR CONVECTION WILL INCREASE BY FRIDAY AS A COLD FRONT MOVES INTO THE AREA. DRIER HIGH PRESSURE BUILDING INTO THE REGION MAY LIMIT COVERAGE OF CONVECTION BY THE END OF THE WEEKEND. BEST CHC OF OVERNIGHT RESTRICTIONS THROUGH THE PERIOD WILL BE IN AREAS THAT SEE LOCALLY HEAVY RAIN. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR GAZ029. NC...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR NCZ071-072- 082. SC...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR SCZ009- 011>014-019. && $$ SYNOPSIS...JOH NEAR TERM...MCAVOY/RWH SHORT TERM...NED LONG TERM...JOH AVIATION...MCAVOY/RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
247 PM EDT WED JUL 25 2012 .SYNOPSIS... A WEAK UPPER LEVEL RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE REGION TONIGHT THROUGH THURSDAY BRINGING VERY WARM AND MUGGY CONDITIONS. A COLD FRONT IS EXPECTED TO MOVE ACROSS THE CAROLINAS AND NORTHEAST GEORGIA LATE FRIDAY AND INTO SATURDAY. ANOTHER RIDGE OF HIGH PRESSURE BUILDS BACK IN SUNDAY AND REMAINS THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/... SO FAR THE WORKED-OVER AIRMASS BEHIND THIS MORNING/S MCS HAS NOT SPAWNED ANY NEW CONVECTION. HOWEVER...THE CU FIELD IS BECOMING BETTER DEFINED AND RAP SOUNDINGS SHOW VERY HIGH SURFACE-BASED CAPE VALUES...PARTICULARLY ALONG AND JUST EAST OF THE BLUE RIDGE. THEREFORE IT SHOULDN/T BE TOO MUCH LONGER BEFORE CONVECTION BEGINS TO DEVELOP OVER THE HIGH TERRAIN. THE DEEP LAYER SHEAR IS ABOUT 20 KTS FROM THE NORTHEAST...AND ANY CELLS THAT DO DEVELOP SHOULD DRIFT INTO THE FOOHTILLS AND POSSIBLY THE WESTERN PIEDMONT. THE WRF-ARW AND 4KM SPC WRF-NMM ARE BOTH ALREADY WAY OVERDONE WITH CONVECTION OVER THE REGION...THOUGH THEY DO INSIST THAT VIGOROUS DEVELOPMENT WILL OCCUR. THE BOTTOM LINE IS THAT I/LL CONTINUE TO CARRY CHANCE POPS THE REST OF THE AFTN AND EVENING HOURS...WITH THE HIGHEST POPS ACROSS THE MTNS AND THE LOWEST ACROSS THE PIEDMONT. HOWEVER...WITH SUCH AN UNSTABLE ATMOSPHERE AND SEVERAL WEAK BNDRY/S OVER THE REGION IT/S ENTIRELY POSSIBLE THAT SCATTERED STORMS...ONCE THEY FORM...WILL WORK SOUTHEASTWARD ACROSS MUCH OF THE REGION DURING THE EVENING HOURS. A FEW SEVERE STORMS ARE A GOOD BET ONCE THEY START TO FIRE. THE ATMOSPHERE WILL WARM UP CONSIDERABLY TOMORROW AS THE CENTER OF A HOT DEEP LAYER RIDGE MOVES ACROSS THE REGION. HEAT INDEX VALUES SHOULD RISE INTO THE HEAT ADVISORY CRITERIA RANGE FOR SEVERAL HOURS IN THE AFTERNOON ACROSS THE CHARLOTTE METRO AREA...THE SOUTHERN UPSTATE AND IN ELBERT COUNTY GEORGIA. CLOSER TO THE MOUNTAINS DEWPOINTS ARE EXPECTED TO MIX OUT ENOUGH IN THE AFTERNOON TO KEEP THE HEAT INDEX BELOW ADVISORY CRITERIA. WITH WARMING MID LEVEL TEMPS...VERY LITTLE SHEAR AND DEWPOINTS MIXING OUT DURING THE AFTN...CONVECTION IS EXPECTED TO BE ISOLATED AND MAINLY CONFINED TO THE MOUNTAINS. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... AS OF 230 PM EDT WEDNESDAY...ON FRIDAY...A COLD FRONT WITH ACTIVE PRE-FRONTAL CONVECTION IS EXPECTED OVER MIDDLE KY/TN DURING THE PRE DAWN HOURS. THE FRONT AND PRE-FRONTAL TROF WILL APPROACH THE SOUTHERN APPALACHIAN REGION DURING THE MORNING AS A L/W TROF DEEPENS OVER THE MID WEST. CONVECTION IS EXPECTED OVER THE MTNS BY MID DAY...PUSHING EAST OF THE MTNS DURING THE AFTERNOON AND EVENING. THE ENVIRONMENT AHEAD OF THE CONVECTIVE BAND WILL FEATURE LLVL BULK SHEAR VALUES APPROACHING 20 KTS WITH CAPE RANGING FROM 1500 TO 2000 J/KG. A FEW ORGANIZED STORM CLUSTERS MAY DEVELOP ALONG AND AHEAD OF THE FRONT...POSSIBLY YIELDING DAMAGING WINDS AND HAIL. THE LATE DAY PASSAGE OF CONVECTION SHOULD ALLOW HIGH TEMPERATURES TO REACH THE U90S EAST OF THE MTNS. RETURN FLOW AHEAD OF THE FRONT WILL SUPPORT DEWPOINT VALUES IN THE U60S. THE COMBINATION OF THE HOT TEMPERATURES AND MODERATE HUMIDITY SHOULD YIELD HEAT INDEX VALUES ALONG AND EAST OF I-85 TO REACH NEAR 105 DURING THE LATE AFTERNOON. HEAT ADVISORY CRITERIA MAY BE REACHED EAST OF I-85. ON SATURDAY...THE CWA SHOULD REMAIN LARGELY IN A POST FRONTAL ENVIRONMENT...WITH NW LLVL WINDS. DOWNSLOPE FLOW AND LINGERING MILD THICKNESSES WILL SUPPORT HIGHS IN THE U80S ACROSS THE MTN VALLEYS AND MID 90S ALONG AND EAST OF I-85. DEWPOINTS MAY ALSO DECREASE A FEW DEGREES IN THE WAKE OF THE FRONT. FORECAST SOUNDINGS CONTINUE TO SHOWS CAPE VALUES AROUND 2000 J/KG DURING THE AFTERNOON. HOWEVER...A SHALLOW LAYER OF CIN MAY EXIST BELOW THE LFC AND AND AN WEAK INVERSION WITHIN THE MID LEVEL MAY LIMIT DEEP CONVECTION. GIVEN THE INSTABILITY AND THE PASSAGE OF THE MID LEVEL TROF I WILL ADVERTISE SCHC POPS DURING THE AFTERNOON. IF CONVECTION DOES DEVELOP...THETA-E LAPSE RATES IN THE MID 30S COULD SUPPORT A DAMAGING WET MICROBURST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 200 PM EDT WEDNESDAY...THE LATEST MODELS CONTINUE TO INDICATE THAT THE UPPER TROUGH PERSISTS OVER THE EASTERN CONUS AND A BROAD UPPER LEVEL RIDGE OF HIGH PRESSURE REMAIN IN PLACE OVER THE GREAT PLAINS THROUGH THE EXTENDED FORECAST PERIOD. AT THE SURFACE...A FAIRLY STRONG HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE REGION FROM THE NORTH BY LATE SATURDAY AND REMAINS THROUGH SUNDAY FOR MOSTLY DRY WEATHER WITH SEASONABLY WARM TEMPERATURES. AS THE HIGH MOVES OFF TO THE EAST MONDAY...A SURFACE LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE CAROLINAS AND LINGERS INTO WEDNESDAY. THIS WILL RESULT IN UNSETTLED WEATHER PATTERN AND COOLER TEMPERATURES ACROSS MUCH OF OUR CWA. TEMPERATURES WILL REMAIN NEAR...OR A COUPLE DEGREES ABOVE NORMAL THROUGH TUESDAY WITH AFTERNOON HIGHS IN THE LOW 90S OVER THE PIEDMONT. TEMPERATURES WILL DROP 5-10 DEGREES BY WEDNESDAY WITH HIGHS IN THE MID 80S OVER THE PIEDMONT AND 70S MTNS. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... AT KCLT...THE TDWR SHOWS THAT SOUTHWEST WINDS ARE GRADUALLY WORKING TOWARD THE SURFACE...AND I HAVE SW WINDS STARTING AT 19 UTC. TSTMS SHOULD DEVELOP ALONG THE BLUE RIDGE AND DRIFT INTO THE FOOTHILLS THIS EVENING. IT/S CERTAINLY POSSIBLE THAT CONVECTION WILL MAKE IT AS FAR EAST AS THE AIRFIELD BY LATE EVENING...BUT I DON/T HAVE MUCH CONFIDENCE IN THAT SOLUTION. THEREFORE I JUST HAVE SOME VCSH FOR THE LATE AFTN HOURS. NOT LOOKING FOR ANY SIGNIFICANT SIG OR VSBY RESTRICTIONS OVERNIGHT...THOUGH A PERIOD OF MVFR FOG IS POSSIBLE. WINDS WILL BE LIGHT OVERNIGHT...INCREASING TO AROUND 10 KTS FROM THE SOUTHWEST THU AFTN. AND ELSEWHERE...SCT TSTMS SHOULD START TO FIRE OVER THE MTNS WITHIN THE NEXT 1 TO 2 HOURS. THE STORMS MAY DRIFT INTO THE UPSTATE DURING THE EVENING HOURS. THIS HAS BEEN ACCOUNTED FOR WITH A VCTS AT MOST AIRFIELDS. OTHERWISE WINDS WILL BE MAINLY OUT OF THE SW THIS AFTN...LIGHT TONIGHT...AND INCREASING TO AROUND 10 KTS FROM THE SW ON THURSDAY. IT WILL BE QUITE HOT TOMORROW...BUT THERE DOESN/T APPEAR THAT THERE WILL BE MUCH THUNDERSTORM ACTIVITY AS A STRONG RIDGE BUILDS ACROSS THE REGION. OUTLOOK...CHANCE FOR CONVECTION WILL INCREASE BY FRIDAY AS A COLD FRONT MOVES INTO THE AREA. DRIER HIGH PRESSURE BUILDING INTO THE REGION MAY LIMIT COVERAGE OF CONVECTION BY THE END OF THE WEEKEND. BEST CHC OF OVERNIGHT RESTRICTIONS THROUGH THE PERIOD WILL BE IN AREAS THAT SEE LOCALLY HEAVY RAIN. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR GAZ029. NC...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR NCZ071-072- 082. SC...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR SCZ009- 011>014-019. && $$ SYNOPSIS...JOH NEAR TERM...MCAVOY SHORT TERM...NED LONG TERM...JOH AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
211 PM CDT WED JUL 25 2012 .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...THE MAIN CONCERN IN THE SHORT TERM IS THE POTENTIAL INFLUENCE OF THE CONV COMPLEX THAT HAS BEEN FIRING TODAY JUST OFFSHORE OF THE MEXICAN COASTLINE BETWEEN BRO AND TAMPICO. BOTH THE RUC AND NAM PICK UP ON A MID LEVEL VORT LIKELY INDUCED BY THIS CONV AND MOVE IT NORTHWARDS STEADILY THROUGH THURS AND THURS NIGHT. THE UPPER LEVEL SUPPORT FROM THIS FEATURE WILL COMBINE WITH THE FAIRLY ELEVATED CAPE VALUES EVIDENT FROM THE CURRENT LAPS FIELDS AND THE 12Z BRO SOUNDING TO SET THE STAGE FOR THE FORMATION OF ISOLD TO SCT CONV MAINLY ALONG AND JUST OFFSHORE OF THE LOWER TX COASTLINE LATER TONIGHT INTO THURSDAY NIGHT. THE NAM AND RUC GUIDANCE BOTH TRY TO PICK UP ON THE MID LEVEL VORT LOCATED NEAR THE HEART OF THE CONV AND ADVECT IT STEADILY NORTHWARDS ALONG OR JUST OFFSHORE OF THE SOUTH TX COASTLINE. THE GFS ALSO PICKS UP ON THIS FEATURE AND MOVES IT NORTH TOWARDS THE LOWER TX COASTLINE BUT UNDERPLAYS THE OVERALL DEEPER LAYER MOISTURE POOL OVER THE REGION. SO GFS HAS LITTLE OR NO POPS FOR THE REGION WHILE THE NAM BUILDS UP SOME HIGHER POPS NEAR THE LOWER TX COASTLINE. WILL BE GOING WITH THE NAM GUIDANCE FOR BOTH TEMPS AND POPS SINCE THIS MODEL APPEARS TO BE INITIALIZING THE BEST ON THIS CONV COMPLEX. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AT THE ONSET OF THE LONG TERM PERIOD UPPER RIDGING BEGINS TO BUILD OVER THE SOUTHEASTERN ROCKY MOUNTAIN REGION AND SHIFT MORE TOWARDS THE CENTRAL PLAINS...WHILE AT THE SURFACE RELATIVELY STRONG RIDGING IS PROGGED TO BE CENTERED OVER THE EAST CENTRAL GULF OF MEXICO AND THE NORTHERN PLAINS. WEAK LEE TROUGHING IN RESPONSE TO A WEAK RETREATING UPPER LOW MAY REMAIN PRESENT ENOUGH FRIDAY TO ALLOW FOR ONE MORE BREEZIER THAN NORMAL DAY BUT THAT SHOULD QUICKLY REMOVE ITSELF AS A PLAYER FROM OUR WEATHER PATTERN BY SATURDAY. THE OVERALL THEME OF THE PATTERN WILL CONTINUE TO BE WARM...POSSIBLY HOT...AND DRY. WINDS SHOULD BE FAIRLY STEADY AND SEASONABLE OUT OF THE SOUTHEAST AT 10 TO 15 MPH IN THE AFTERNOON. PWAT VALUES REMAIN FAIRLY LOW AND A SUBSIDENCE INVERSION WILL LIKELY SET UP IN SOME FORM IN RESPONSE TO THE BUILDING RIDGING OVER NORTHERN TEXAS AND THE CENTRAL PLAINS. THE BEST WINDOW FOR ANY PRECIP FOR NOW LOOKS TO BE SUNDAY IN THE AFTERNOON HOURS AS GFS40/ECMWF BOTH SLIDE A LITTLE BIT OF TROPICAL MOISTURE ASSOCIATED WITH A WEAK WAVE IN VIA A WEAKNESS IN THE RIDGE TO THE EAST AND OUR NORTH. DID ADD SOME SCHC SHRA/TSRA TO THIS PERIOD GIVEN THE REASONABLE CONSENSUS ON TIMING FROM EC/GFS. A PRIMARY CONCERN IN THIS PERIOD MAY BE PROLONGED ABOVE NORMAL TEMPERATURES. DEEP LAYER AND LOW LEVEL THICKNESSES WILL BE QUITE HIGH WITH STRONG INSOLATION AMID FEW TO SCATTERED CLOUDS. THE SURFACE FLOW IS PROJECTED TO BE A LITTLE MORE SOUTHEASTERLY THAN SOUTHERLY...BUT A FEW VERY HOT DAYS WILL BE POSSIBLE GIVEN THE STRENGTH OF THE RIDGE. BUMPED UP TEMPERATURES SLIGHTLY FROM THE GOING FORECAST WHICH CONTINUES TO SIT A LITTLE ABOVE GUIDANCE CONSENSUS. HEAT INDICIES FROM 105 TO 110 WILL BE VERY MUCH IN PLAY DURING THE SUNDAY TO WEDNESDAY PERIOD...WITH HEAT ADVISORY CRITERIA HEAT INDICIES POSSIBLE. && .MARINE /TONIGHT THROUGH THURSDAY NIGHT/...CURRENTLY THE PGF ALONG THE LOWER TX BAY AND GULF WATERS HAS PUSHED CONDITIONS UP INTO SCEC LEVELS THIS AFTERNOON. EXPECT THIS PGF TO PERSIST THROUGHOUT THE SHORT TERM PERIOD KEEPING THE BAY AND GULF WATERS CLOSE TO SCEC/BORDERLINE SCA CRIT THROUGH TOMORROW NIGHT. THE MARINE CONV PUSHING UP FROM THE SOUTH MAY BRIEFING BOOST THE WINDS AND SEAS UP CLOSE TO SMW CRIT DUE TO THE CONV OUTFLOW. HOWEVER WILL NOT POST ANY SCAS AT THIS TIME. .FRIDAY THROUGH SUNDAY.... PERSISTENT MODERATE SOUTHEASTERLY WINDS ARE EXPECTED DURING THE PERIOD. THE STRONGEST WINDS FOR NOW ARE EXPECTED ON FRIDAY. SCEC CONDITIONS ON THE LAGUNA IN THE AFTERNOON AND THE EVENING IN THE OFFSHORE WATERS ARE POSSIBLE DURING THIS TIME. WINDS AND SEAS SHOULD STAY BELOW SCEC CRITERIA SATURDAY AND SUNDAY WITH SEAS GENERALLY EXPECTED TO BE BETWEEN THREE AND FIVE FEET. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV SHORT TERM...SPEECE LONG TERM...GIBBS UPPER AIR/GRAPHICAST...MARTINEZ
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
111 PM CDT WED JUL 25 2012 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...THE MAIN CONCERN IN THE SHORT TERM IS THE POTENTIAL INFLUENCE OF THE CONV COMPLEX THAT HAS BEEN FIRING THIS MORNING JUST OFFSHORE OF THE MEXICAN COASTLINE BETWEEN BRO AND TAMPICO. BOTH THE RUC AND NAM PICK UP ON A MID LEVEL VORT POSSIBLY INDUCED BY THIS CONV AND MOVE IT NORTHWARDS STEADILY THROUGH THURS AND THURS NIGHT. THIS WILL ALLOW FOR ISOLD TO SCT CONV TO BUILD MAINTAIN ALONG AND JUST OFFSHORE OF THE LOWER TX COASTLINE POSSIBLY REDUCING CEILINGS AND VSBYS BRIEFLY DOWN TO MVFR/IFR LEVELS LATER TONIGHT OR THURSDAY MORNING. AT THIS TIME MY OVERALL CONFIDENCE LEVEL WITH THIS FEATURE IMPACTING THE AREA AIRPORTS IS TOO LOW TO INCLUDE ANY MENTION WITH THE 18Z ISSUANCE SINCE MOST OF THE STRONGER CONV MAY BE LIMITED TO THE BAY AND GULF WATERS. FOR NOW WILL MAINTAIN VFR CONDITIONS. && .PREV DISCUSSION... /ISSUED 658 AM CDT WED JUL 25 2012/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...VFR IS ANTICIPATED THROUGH THE NEXT 24 HOURS. SURFACE WINDS WILL INCREASE THROUGH THE DAY TODAY WITH SCATTERED CLOUDINESS. WINDS WILL BEGIN TO DIMINISH TO LIGHT TO MODERATE LEVELS AROUND SUNSET THIS EVENING WITH A FEW CLOUDS REMAINING OVERNIGHT TONIGHT. PREV DISCUSSION... /ISSUED 243 AM CDT WED JUL 25 2012/ SHORT TERM.../TODAY THROUGH THURSDAY/...ISOLATED STREAMER SHOWERS ARE LOCATED OVER THE LOWER TEXAS COASTAL WATERS RIGHT NOW...A TREND THAT SHOULD REPEAT ITSELF AGAIN TONIGHT. OTHERWISE...DOMINANT MID-LEVEL HIGH PRESSURE CENTERED OVER THE SOUTHEAST UNITED STATES WILL PREVAIL OVER DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY...PRODUCING DRY WEATHER WITH VERY HOT TEMPERATURES TODAY AND THURSDAY. A COMBINATION OF RELATIVE HUMIDITY PERCENTAGES AND WINDS AT THE 20-FOOT LEVEL MAY LEAD TO AN ENHANCED RISK OF WILDFIRE GROWTH AND SPREAD ON THURSDAY... HOWEVER A RED FLAG WARNING IS NOT EXPECTED TO BE NEEDED AT THAT TIME. LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY/... NO BIG CHANGES DONE TO THE LONG TERM FORECAST AT THIS TIME. A BENIGN WEATHER PATTERN REMAINS THROUGH THE WEEK WITH LITTLE CHANCE OF ANY CONVECTION. HOT TEMPERATURES WILL BE THE MAIN THREAT THIS WEEK REMAINING IN THE TRIPLE DIGITS FOR CONSECUTIVE DAYS. RIDGE OVER THE DESERT SW SHIFTS TO THE CENTRAL PLAINS INTO THE WEEKEND. S/SE FLOW WILL REMAIN BETWEEN 15 TO 20 KNOTS ACROSS THE RIO GRANDE VALLEY DUE TO A STRENGTHENING GRADIENT ALONG THE COASTAL COUNTIES. EXPECT THIS BREEZE CONDITIONS TO CONTINUE INTO SUNDAY AS GRADIENT REMAINS STRONG. SOUTHEAST WINDS DECREASE INTO NEXT WEEK AS GRADIENT WEAKENS WITH WINDS BETWEEN 10 HO 15 KNOTS. HOT TEMPERATURES WILL FEEL BETWEEN THE MID 100S TO THE HIGH 90S. ABUNDANT MOISTURE OVER CENTRAL MEXICO BORDER WILL REMAIN OVER THE REGION WITH SOUTHEAST FLOW MOVING MOISTURE TOWARDS THE ARIZONA AND NEW MEXICO BORDER ENHANCING A MONSOONAL PATTERN IN THIS LOCATIONS. THIS MOISTURE WILL REMAIN FAR WEST FROM THE CWA WHICH WILL LIMIT THUNDERSTORM ACTIVITY FOR THE RIO GRANDE VALLEY. HIGH PRESSURE INTENSIFIES ALONG THE NORTHWESTERN PACIFIC REGION BY MID WEEK. DRY AIR WILL INFILTRATE ACROSS THE WESTERN PORTION OF THE CWA KEEPING A DRY PATTERN ACROSS THE AREA. LOW TEMPERATURE WILL BE BETWEEN IN THE 80S. MARINE...TODAY THROUGH THURSDAY...BUOY 42020 REPORTED SOUTH WINDS AROUND 18 KNOTS GUSTING TO AROUND 21 KNOTS WITH SEAS SLIGHTLY UNDER 3.5 FEET WITH A PERIOD OF 4 SECONDS AT 02 CDT/07 UTC. MODERATE WINDS AND SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST TODAY THROUGH TONIGHT AS HIGH PRESSURE OVER THE GULF OF MEXICO INTERACTS WITH LOW PRESSURE OVER NORTHERN MEXICO. SMALL CRAFT WILL LIKELY NEED TO EXERCISE CAUTION DURING THIS TIME ALONG THE LOWER TEXAS COAST. ON THURSDAY...A COMBINATION OF SMALL CRAFT EXERCISE CAUTION AND SMALL CRAFT ADVISORY IS LIKELY DUE TO CONTINUED MODERATE SEAS AND SLIGHTLY STRONGER WINDS. THURSDAY NIGHT THROUGH WEDNESDAY... BENIGN WEATHER EXPECTED WITH S/SE WINDS THROUGH THE LONG TERM PERIOD. EXPECT SEAS TO REMAIN BETWEEN 2 TO 4 FEET FRIDAY WITH SE WINDS. THIS WINDS WILL BEGIN TO LOWER FOR THE WEEKEND AND REMAIN BETWEEN 2 TO 3 FEET THE REMAINDER OF THE LONG TERM PERIOD. NO SCA OR SCEC EXPECTED AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 81 96 82 90 / 0 0 0 0 BROWNSVILLE 79 96 80 93 / 0 0 0 0 HARLINGEN 78 100 79 96 / 0 0 0 0 MCALLEN 79 102 80 98 / 0 0 0 0 RIO GRANDE CITY 79 102 79 99 / 0 0 0 0 SOUTH PADRE ISLAND 82 91 83 86 / 0 0 10 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV SHORT TERM...60 LONG TERM...68
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1238 PM CDT WED JUL 25 2012 .AVIATION... STILL EXPECT ISOLATED TO SCATTERED THUNDERSTORMS DEVELOP LATE THIS AFTN IN A MOISTURE AXIS LOCATED NEAR THE CAPROCK ESCARPMENT AS WELL AS ON THE HIGH TERRAIN ALONG THE NEW MEXICO STATE LINE. FAVORED MOVEMENT OF STORMS TOWARD AN EASTERLY COMPONENT COULD BRING TSRA TO BOTH TAF SITES. HOWEVER...AREAL EXTENT WITHIN 9 HOUR WINDOW NOT HIGH ENOUGH TO WARRANT TEMPO GROUPS ATTM. THUS WILL PULL THUNDER MENTION FROM BOTH TAFS AND REEVALUATE LATER THIS AFTN. && .PREV DISCUSSION... /ISSUED 633 AM CDT WED JUL 25 2012/ AVIATION... VFR CONDITIONS WILL CONTINUE THROUGH THE DAY. BY EARLY AFTERNOON...ISOLATED TO SCATTERED THUNDERSTORMS MAY DEVELOP NEAR THE KLBB TERMINAL AND EVENTUALLY SPREAD TOWARDS THE KCDS TERMINAL. PRECIPITATION SHOULD END BEFORE MIDNIGHT LEAVING VFR CONDITIONS IN PLACE. JORDAN PREV DISCUSSION... /ISSUED 403 AM CDT WED JUL 25 2012/ SHORT TERM... 00Z UPPER-AIR ANALYSIS AND WV SATELLITE SHOWS CONSIDERABLE MOISTURE IN PLACE ACROSS THE REGION. KAMA AND KMAF RESPECTIVELY HAVE 1.14 AND 1.11 INCH PRECIPITABLE WATER VALUES WHICH IS SOMEWHAT HIGH FOR THIS TIME OF YEAR. ALSO ARE SEEING SOME SHOWERS EARLY THIS MORNING ON THE RADAR ASSOCIATED WITH AN AREA OF MID-LEVEL CLOUD COVER. UPPER-AIR ANALYSIS SHOWS A TROF AXIS LOCATED ACROSS EASTERN NEW MEXICO THIS MORNING WITH THE MODELS SLOWLY SHIFTING THIS TOWARDS THE STATE LINE THROUGH THE DAY. MONSOON MOISTURE PLUME SHOULD MOVE BACK OVER THE WESTERN HALF OF THE FORECAST AREA THIS AFTERNOON AND DAYTIME HEATING SHOULD HELP TO DESTABILIZE THE ATMOSPHERE RESULTING IN A BIT MORE WIDESPREAD STORM ACTIVITY COMPARED TO YESTERDAY. ALL OF THIS IS ACCORDING TO THE VARIOUS RESOLUTIONS OF THE NAM MODEL AND TO LESSER EXTENT THE TTU WRF. THE GFS AND LATEST HRRR ARE NOT AS OPTIMISTIC AT ALL. WILL KEEP CHANCE OF THUNDERSTORMS OVER THE CENTRAL SOUTH PLAINS WHERE THE INSTABILITY AXIS MAY TRY TO SET UP THIS AFTERNOON AND THEN SHIFT THIS AREA WEST FOR EARLY TONIGHT. THERE COULD BE A FEW SHOWERS THAT LINGER ACROSS THE AREA INTO THURSDAY MORNING AS MONSOON MOISTURE AND TROF AXIS REMAIN NEAR THE REGION. HIGH TEMPERATURES CAME IN A BIT WARMER ON THE MOS GUIDANCE AND WILL KEEP THINGS A FEW DEGREES UNDER THIS DUE TO THE EXPECTED CLOUD COVER AND SHOWERS. JORDAN LONG TERM... THE EXTENDED FORECAST WILL BE PUNCTUATED BY MORE SUMMER HEAT...THOUGH THUNDERSTORMS MAY ALSO GIVE SOME LOCATIONS BRIEF RELIEF THURSDAY AND/OR FRIDAY. A SHORTWAVE TROUGH WILL GLIDE ACROSS THE MIDWEST ON THURSDAY...JUST GRAZING THE SOUTHERN PLAINS WITH WEAK 500-300 MB LAYER Q-VECTOR CONVERGENCE AND DRAWING THE MONSOONAL MOISTURE PLUME ACROSS WEST TEXAS. AT THE SAME TIME...THE TAIL END OF A COLD FRONT WILL EDGE TOWARD OR INTO THE AREA. THE 00Z GFS AND NAM DO HAVE THE THE WIND SHIFT ROUGHLY BISECTING THE FA FROM SW TO NE MIDDAY THURSDAY BEFORE STALLING OUT...WHILE THE ECMWF IS SOMEWHAT FURTHER NORTH...INTO THE TEXAS PANHANDLE. GIVEN THAT THE POSITION OF THE FRONTAL ZONE IS SOMEWHAT IN QUESTION...DETAILS IN CONVECTIVE INITIATION ALSO REMAIN SOMEWHAT UNCERTAIN...BUT WITH WEAK UPPER SUPPORT AND A RELATIVELY MOIST ATMOSPHERE IN PLACE /PWATS AT 130 TO OVER 150 PERCENT OF AVERAGE/...EXPECT DAYTIME HEATING TO LEAD TO SCATTERED AFTERNOON AND EVENING CONVECTION. PROGGED SFC MOISTURE AND RESULTANT INSTABILITY WILL BE A LITTLE HIGHER THAN WE HAVE SEEN RECENTLY THOUGH DEEP-LAYER SHEAR WILL STILL BE RATHER MEAGER. HENCE...DO NOT ANTICIPATE MUCH STORM ORGANIZATION...BUT COULD SEE A FEW STRONGER CORES THAT COULD PRODUCE SMALL HAIL...STOUT DOWNBURST WINDS AND LOCALLY HEAVY RAINS. ANY WEAK UPPER SUPPORT THURSDAY WILL QUICKLY WANE FRIDAY AS AN UPPER LEVEL RIDGE STRENGTHENS AND EXTENDS EASTWARD FROM THE SOUTHERN ROCKIES INTO THE SOUTHERN PLAINS. STILL...RESIDUAL LOW-LEVEL MOISTURE...A THINNING MID-LEVEL MOISTURE PLUME...STRONG HEATING AND PERHAPS A SFC BOUNDARY IN THE AREA MAY BE ENOUGH TO GENERATE ISOLATED TO WIDELY SCATTERED CONVECTION FRIDAY AFTERNOON AND EVENING. BEYOND THAT...THOUGH...THE UPPER RIDGE WILL BECOME CENTERED ACROSS THE SOUTHERN PLAINS AND IT SHOULD PUT THE KIBOSH ON STORM CHANCES THIS WEEKEND AND INTO AT LEAST THE FIRST PART OF NEXT WEEK AS IT PROMOTES SUBSIDENCE AND SHIFTS THE MONSOON MOISTURE BACK TO THE WEST. THE UPPER RIDGE AXIS MAY ATTEMPT TO SHIFT BACK WEST OF THE AREA BY DAY 7 OR DAY 8 IF THE GFS IS CORRECT...BUT THE ECMWF KEEPS THE CENTER OF THE HIGH NEARBY THROUGH THE REMAINDER OF NEXT WEAK. THUS...EXPECT HOT TEMPERATURES TO CONTINUE...AND HAVE FAVORED HIGHS SLIGHTLY ABOVE GUIDANCE FROM THIS WEEKEND ONWARD...GIVEN RECENT GUIDANCE BIASES WITH THE PREVIOUS UPPER RIDGE ACROSS THE SOUTH PLAINS THIS PAST WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 95 67 94 66 92 / 20 30 30 30 20 TULIA 94 68 96 67 92 / 20 30 30 30 20 PLAINVIEW 94 69 94 69 92 / 30 20 30 30 20 LEVELLAND 95 69 95 69 93 / 30 20 30 30 20 LUBBOCK 96 71 96 71 95 / 30 20 30 30 20 DENVER CITY 96 70 96 69 94 / 20 20 30 30 20 BROWNFIELD 95 71 96 69 94 / 30 20 30 30 20 CHILDRESS 100 75 100 74 99 / 20 20 30 30 20 SPUR 97 72 98 72 100 / 30 20 30 30 20 ASPERMONT 99 76 102 76 101 / 30 20 30 30 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07
AREA FORECAST DISCUSSION
NWS SPOKANE WA
232 PM PDT Wed Jul 25 2012 .SYNOPSIS... Low pressure off and along the coast propped up against higher pressure in the vicinity of the Northern Rockies will keep a very minor southwest to northeast oriented storm track in the vicinity of Eastern Washington and Northern Idaho into next week. This pattern will should result in near normal temperatures through much of this and the following workweek. && .DISCUSSION... Tonight: Slow moving thunderstorms will be our main focus this evening. With very little wind in the lowest 10 thousand feet of the model soundings, localized heavy rain will be the main impact from storms through mid evening. Look for cells to be short lived, but capable of producing heavy rain rates. This is typically what we experience in a moderate instability and weak shear environment. The 2 PM radar imagery shows scattered showers and thunderstorms over the high terrain near Mazama, Oroville, Republic and Curlew. The RUC model suggests that the atmosphere is favorable for development further south along the Cascade Crest down toward Stevens and Stampede Pass with CAPE values approaching 1000 J/KG. Increased convective development can also be expected over the high terrain around Kettle Falls, Priest Lake and Bonners Ferry through early evening. By late afternoon and early evening there may be a better chance of getting some of the cells to survive as they descend into the low elevations. But the heaviest rains will likely fall over the mountains where storms are initiated since they collapse quickly in the weak shear environment. Overnight, there is a small chance of high based showers, mainly south of the Spokane forecast area. The GFS and NAM show some conditional instability mainly above 600mb. With a very dry air mass from 700mb and below, any showers that develop will probably not produce much measurable rain. The best elevated instability on the NAM and GFS prior to sunrise will be over the Oregon portion of the Columbia Basin. After sunrise the 600-500mb negative theta-e lapse rates migrate over the Palouse into the southern and central Idaho Panhandle. Chances for measurable precipitation is very low, so I limited the precipitation chances to 15 percent or less. We may need to add sprinkles into the forecast if we see some high based showers develop on radar late this evening. /GKoch Thursday through Saturday...A prolonged period of southwest flow due to the positioning of a long-wave trof off the coast juxtaposed against ridge of high pressure with axis remaining somewhere in Montana influences this time interval. Since the ridge to the east is not all that well amplified and the southwest flow is not too southerly in origin forecast temperatures remain very close to normal. Additionally any mention of precipitation including thunderstorms possibly fired off by small disturbances passing through the discussed prevailing southwest to northeast flow remains low but not zero given the weakness of the depicted disturbances. There does appear to be enough moisture and energy though via a ridge in the 700MB equivalent potential temperature fields running through Eastern Oregon up into North Idaho...which is pretty much aligned with the described prevailing southwest flow. The best chance of any convection getting fired off is on Friday as that wave has the best potential...but the pop still remains low. /Pelatti Saturday night through Wednesday: Synoptic scale pattern will remain stagnant as an expansive ridge of high pressure dominates the central United States. This omega block pattern type will prevent low pressure over the Gulf of Alaska to shift over the Pac Northwest. We will remain under dry southwest flow between this area of lower pressure to our west and higher pressure to our east. There will be the possibility for some disturbances that rotate around the Gulf of Alaska low that could impact the region. However, moisture off the Pacific will be lacking, and without much of a southerly component in the flow pattern, we will be hard pressed to draw up any monsoonal moisture as well. Models are picking up on a weak disturbance that moves through off the Pacific on Sunday, which may produce some breezy winds. We may see some more weak disturbances that move across the area next week, but most of the energy associated with the low in the Gulf of Alaska looks to stay to our north into British Columbia. Without any discernible strong frontal systems with big air mass changes, temperatures will be fairly consistent through the period. Expect temperatures to be close to seasonal averages under clear or mostly clear sky conditions. /SVH && .AVIATION... 18Z TAFS: Some cumulus build ups over the mountains near the Canadian border along with isolated showers and thunderstorms but TAF sites should remain mostly clear with light winds through 18Z Thursday. /Pelatti && .PRELIMINARY POINT TEMPS/POPS... Spokane 63 89 62 87 59 84 / 0 10 10 20 20 0 Coeur d`Alene 57 88 58 87 56 84 / 0 0 10 20 20 0 Pullman 52 88 56 87 53 83 / 10 10 10 20 20 0 Lewiston 64 95 66 94 63 91 / 10 10 10 20 20 0 Colville 56 91 58 90 56 87 / 10 10 10 20 20 10 Sandpoint 53 86 53 85 52 81 / 10 10 10 20 20 0 Kellogg 54 88 58 86 55 81 / 0 10 10 20 20 10 Moses Lake 61 93 62 92 58 88 / 10 0 0 0 10 0 Wenatchee 66 93 66 90 63 87 / 0 0 0 0 10 0 Omak 64 92 60 92 57 88 / 10 10 20 20 20 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1211 PM CDT WED JUL 25 2012 .UPDATE... CIRRUS FROM THE STORMS TRACKING ACROSS NORTHERN WISCONSIN WILL CONTINUE TO GRADUALLY THIN THROUGH EARLY AFTERNOON. FURTHERMORE...HOT 925MB TEMPS 32C TO 34C WILL BE ADVECTING INTO SOUTHERN WI LATE THIS AFTERNOON. SO DESPITE THE SLOW WARMING TREND INTO THE 80S THIS MORNING...STILL EXPECTING A JUMP IN THE TEMPS BY 3 PM INTO THE UPPER 90S TO AROUND 100. DEWPOINT TEMPS HAVE BEEN STEADILY INCREASING INTO THE LOWER 70S THIS MORNING. WITH CAPPING INVERSION AND SURFACE TROUGH DRAPED ACROSS CENTRAL WI...EXPECT THESE 70S DEWPOINTS TO POOL IN SOUTHEAST WI FOR A GOOD PORTION OF THE AFTERNOON. AS WINDS BECOME SOUTHWESTERLY IN THE WESTERN FORECAST AREA EARLY THIS AFTERNOON...EXPECT SOME MODERATE MIXING OF DEWPOINTS BACK INTO THE MID 60S FOR A TIME. DEWPOINTS WILL INCREASE ONCE AGAIN AS THE COLD FRONTAL BOUNDARY APPROACHES. SHOWERS DEVELOPED IN CENTRAL WI AS AN OUTFLOW BOUNDARY INTERSECTED A GRAVITY WAVE. THE LIGHT SHOWERS ARE JUST ENTERING MARQUETTE COUNTY AT THIS TIME. MANY OF THE SMALL SCALE MODELS GENERATE A LINE OR CLUSTER OF CONVECTION AROUND 21Z IN CENTRAL FORECAST AREA /CWA/...POSSIBLY ALONG AN OUTFLOW BOUNDARY OR THAT GRAVITY WAVE. HOWEVER THE ENVIRONMENT SHOULD BE TOO CAPPED TO ALLOW FOR ANY TYPE OF CONVECTION AND WILL DISREGARD. SOUTHERN WISCONSIN REMAINS IN THE SLIGHT RISK AREA. THE MAIN FOCUS FOR THUNDERSTORMS WILL STILL BE LATE THIS AFTERNOON 23Z-00Z IN OUR NW CWA AND APPROX 03Z IN THE CENTRAL FORECAST AREA AND 04Z IN THE SOUTHEAST. IMPRESSIVE D-CAPE AROUND 1500 PER RAP MODEL THIS AFTERNOON IN SOUTHERN WI. MAIN THREAT FOR SEVERE THUNDERSTORMS WILL BE DAMAGING WINDS DUE TO THE DRY LOW LEVELS. DUE TO THE HIGHER DEWPOINTS NOW...CAPE VALUES WILL BE 1500 TO 2000 J/KG THIS AFTERNOON AND COMBINED WITH BULK SHEAR AROUND 30 TO 40 KNOTS WILL SUPPORT A LARGE HAI THREAT AS WELL. WITH THE STRONG INSTABILITY AND SURFACE HEATING...EXPECT STORMS TO FIRE UP PRETTY EASILY ALONG THE SURFACE FRONT. && .AVIATION/18Z TAFS/... CIRRUS SHOULD GRADUALLY THIN THIS AFTERNOON. EXPECTING SCT TO NUMEROUS THUNDERSTORMS TO DEVELOP IN WEST CENTRAL WI LATE THIS AFTERNOON AND TRACK IN A LINE FORMATION SOUTHEASTWARD INTO SOUTHEAST WI THIS EVENING ALONG A COLD FRONT. POTENTIAL FOR CIGS TO LOWER TO MVFR UPON FRONTAL PASSAGE LATER TONIGHT. THERE IS POTENTIAL FOR SEVERE THUNDERSTORMS THIS EVENING...WITH THE MAIN THREAT OF STRAIGHT LINE DAMAGING WINDS. && .PREV DISCUSSION... /ISSUED 330 AM CDT WED JUL 25 2012/ TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM LOW LEVEL JET FEEDING MCS OVER CENTRAL MN PIVOTING MORE TO THE NORTHEAST INTO NORTHERN WI AND THE UP AND AS A RESULT WEAKER THETA-E ADVECTION FARTHER SOUTH TRIGGERING SCATTERED CONVECTION OVER SOUTHERN WI. EXPECT THE CONVECTION TO DIMINISH IN THE EAST AFTER 12Z AS STRONG ADVECTION SLIDES OFF TO THE EAST. BOTH NAM AND GFS SHOW DOWN SLIGHTLY EWD MOVEMENT OF SFC LOW PRESSURE CURRENTLY OVER ERN SODAK. HENCE A SLIGHT DELAY IN SOUTHEAST SFC WINDS BECOMING MORE SOUTH TO SOUTHWESTERLY. DEWPTS HAVE REMAINED IN THE MID 50S TO LOW 60S OVERNIGHT. EXPC DEWPTS TO INCREASE TODAY TO REFLECT HIGHER LOW LEVEL RH TO THE SOUTH AND ADDED MOISTURE FROM SCT RECENT RAINFALL. HOWEVER BETTER MIXING SHOULD RESULT IN KEEPING DEWPTS MORE IN THE MIDDLE TO UPPER 60S...WITH A FEW AWOS SITES REMAINING IN THE 61 TO 65 RANGE. HIGHER DEWPTS LIKELY TO BE FARTHER NORTH...POOLING ALONG APPROACHING SFC BOUNDARY. 00Z UPPER AIR ANALYSIS SHOWS LOW LEVEL ECMWF TEMPERATURES MORE IN BALLPARK THAN VERY WARM NAM. HENCE EXPECTING 925H TEMPS TO WARM TO 31-32C WITH 850H TEMPS AROUND 24-25C THIS AFTN. WITH DRY ADIABATIC LAPSE RATES SETTING UP THIS AFTERNOON...HOT AIR IN THE LOW LEVELS SHOULD BE REALIZED...BUMPING UP TEMPERATURES TO AROUND 100 MANY AREAS. COOLEST SPOTS LIKELY TO BE IN THE NORTH WHERE A BIT MORE CLOUDINESS EXPECTED AND ALONG THE SHEBOYGAN AND OZAUKEE COUNTY SHORELINES WHERE WINDS IN THESE AREAS WILL BE THE LAST TO TURN S TO SW. WL CONTINUE HEAT ADVISORY...BUT POSTPONE IT AN HOUR TO ACCOUNT FOR DELAY IN APPARENT TEMPERATURES WARMING THROUGH THE 90S. 0 TO 6KM BULK SHEAR BORDERLINE SEVERE CRITERIA LATE THIS AFTERNOON AND EVE AS SFC FRONT APPROACHES NORTHERN CWA. BY LATE AFTERNOON...CIN ERASED WITH SFC BASED CAPES APPROACHING 2000J/KG IN THE NORTH. CAN NOT RULE OUT SEVERE THREAT...ESPECIALLY WITH LOW PRESSURE TRAVELING ALONG BOUNDARY INCREASING LOW LEVEL CONVERGENCE. HOWEVER SOUTHWEST WINDS IN THE LOW LEVELS OF THE ATMOSPHERE A NEGATIVE. SHORT TERM GUIDANCE IN GOOD AGREEMENT ON CARRYING SFC LOW INTO LOWER MI THUMB AREA. FAIRLY STRONG AREA OF LOW LEVEL FN VECTOR RESPONSE TO FRONTOGENESIS SLIDES SOUTH ACROSS SOUTHERN WI DURING THE EVENING...SO WL CONTINUE LIKELY WORDING WITH DIMINISHING TREND FROM THE NORTHWEST AFT MIDNIGHT. THURSDAY AND FRIDAY...FORECAST CONFIDENCE...MEDIUM KEPT SOME POPS ACROSS THE SOUTHEAST HALF OF THE FORECAST AREA THURSDAY MORNING...AS THE ECMWF AND CANADIAN LINGER BETTER MOISTURE AND FORCING WITH SHORTWAVE. COULD SEE A FEW MORE SHOWERS/STORMS ACROSS THE FORECAST AREA LATER IN THE DAY AND OVERNIGHT AS A STRONGER SHORTWAVE PUSHES THROUGH. STILL THINKING THE SUN MAY POKE OUT FOR A TIME THURSDAY...SO BUMPED HIGHS UP A BIT MORE PER 925 MB TEMPS IN THE 23-26C RANGE. PRECIP MAY LINGER FRIDAY AS THE SLOWLY SHORTWAVE EXITS...WITH THE BEST CHANCE ACROSS THE NORTHEAST. COOLER AIR ON THE BACKSIDE OF THE WAVE SHOULD RETURN TEMPERATURES TO NEAR NORMAL VALUES. SATURDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH A PLEASANT DAY EXPECTED SATURDAY...WITH HIGH PRESSURE BRINGING PLENTY OF SUNSHINE TO GO ALONG WITH NEAR NORMAL TEMPERATURES. SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE...MEDIUM WITH UPPER RIDGE BUILDING IN TO THE WEST SUNDAY THROUGH TUESDAY...COMBINATION OF WARM AIR ADVECTION AND A WEAK WAVE OR TWO MAY KICK OFF SHOWERS/STORMS AT TIMES. WILL LIKELY SEE TEMPS WARM BACK ABOVE NORMAL THROUGH THIS PERIOD. AVIATION/12Z TAFS/...SCT T SHOULD END EARLY THIS MORNING AS STRONG THETA-E ADVECTION SLIDES OFF TO THE EAST. VFR CONDITIONS EXPECTED FOR MOST OF THE DAY. SCT TO NUMEROUS CONVECTION WL AFFECT SRN WI TNGT AS SFC COLD FRONT AND MID-LEVEL DISTURBANCE MOVE THROUGH OUR AREA. POTENTIAL FOR CIGS TO LOWER TO MVFR UPON FRONTAL PASSAGE LATER TONIGHT. MARINE...WILL CONTINUE SMALL CRAFT ADVY TODAY AS PRESSURE GRADIENT TIGHTENS OVER LAKE MICHIGAN AHEAD OF LOW PRESSURE EXPECTED TO MOVE INTO CENTRAL WI THIS AFTN. SOUTHEAST WINDS WL VEER SLIGHTLY TO SOUTH LATER THIS MRNG AND AFTN. WINDS WL CONTINUE TO VEER TO THE SOUTHWEST AND THEN TURN NORTH UPON FROPA TONIGHT. STILL A THREAT FOR THUNDERSTORMS EARLY THIS MRNG WITH SCT CONVECTION DEVELOPING LATER THIS AFTN AND EVE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR WIZ051-052-058>060- 062>072. HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ046-047-056-057. LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646. && $$ UPDATE...MRC TODAY/TONIGHT AND AVIATION/MARINE...MBK THURSDAY THROUGH TUESDAY...DDV