Area Forecast Discussion
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000 FXUS61 KPBZ 022316 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 716 PM EDT SUN AUG 2 2015 .SYNOPSIS... A COLD FRONT WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TO START THE WORK WEEK. && .NEAR TERM /THROUGH MONDAY/... CUMULUS IS ALREADY FADING QUICKLY AS ABUNDANT DRY AIR IN THE RATHER WELL-MIXED COLUMN QUICKLY ERODES EVEN WITH STRONG LOW LEVEL LAPSE RATES. WIND GUSTS SHOULD START TO DIMINISH AFTER SUNSET...HOWEVER AMPLE MOMENTUM AND A STRENGTHENING PRESSURE GRADIENT ARE LIKELY TO KEEP SOUTHWESTERLY WINDS UP OVERNIGHT. THIS WILL ALLOW FOR YET ANOTHER WARM NIGHT AS THE BOUNDARY LAYER SEEMS LIKELY TO REMAIN MIXED...PARTICULARLY IN THE NORTHERN AND WESTERN AREAS OF THE CWA. OTHERWISE...URBAN HEAT ISLANDS WILL REMAIN STRONG...AND LOWS LOOK POISED TO BE LARGELY IN THE 60S TO NEAR 70 IN THE URBAN AREA. FRIES PREVIOUS DISCUSSION FOR MONDAY FOLLOWS...ATTENTION WILL THEN TURN TO THE LOW PRESSURE SYSTEM CURRENTLY OVER WISCONSIN...WHICH IS RESPONSIBLE FOR SEVERE WEATHER GOING ON THIS AFTERNOON ACROSS WISCONSIN AND MICHIGAN. WHILE THE LOW MOVES EAST OVERNIGHT...THE ASSOCIATED COLD FRONT WILL SLIDE TO THE SOUTHEAST...WITH SHOWERS AND THUNDERSTORMS CONTINUING ALONG THE FRONT. WHILE PRECIPITATION SHOULD PERSIST...HIGH RESOLUTION MODELS HAVE THE SHOWERS WANING AS THE FRONT APPROACHES NORTHERN OHIO NEAR SUNRISE. IF THIS PLAYS OUT...TIMING COULD LIMIT OVERALL POTENTIAL FOR SEVERE WEATHER...WITH SOMEWHAT OF A LULL IN PRECIPITATION ALONG THE FRONT AS IT PASSES OVER THE WESTERN HALF OF OUR FORECAST AREA IN THE MORNING. EVENTUALLY SHOWERS AND STORMS SHOULD DEVELOP AGAIN IN THE AFTERNOON WITH THE DIURNAL CYCLE ACROSS EASTERN PORTIONS OF THE FORECAST AREA. MODELS CONTINUE TO DISAGREE ON AMOUNT OF INSTABILITY THE ATMOSPHERE WILL HAVE TO WORK WITH...ALTHOUGH THERE IS GOOD MODEL AGREEMENT FOR MODEST UNIDIRECTIONAL WIND SHEAR THAT COULD HELP TO ORGANIZE STORMS. THE SPC DAY 2 AFTERNOON UPDATE REMAINS UNCHANGED FROM EARLIER TODAY...LEAVING THE FORECAST AREA UNDER A SLIGHT RISK FOR SEVERE WEATHER...WHICH IS ALREADY HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK. OVERNIGHT LOWS SHOULD REMAIN A BIT WARMER THAN LAST NIGHT CONSIDERING WINDS WILL NOT GO CALM AS WELL AS HIGH CLOUDS MOVING IN BEFORE THE FRONT. MONDAY HIGHS WILL BE A FEW DEGREES COOLER THAN TODAY WITH THE ARRIVAL OF THE COLD FRONT. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE MONDAY EVENING AS THE FRONT CLEARS THE REGION...WITH ONLY SOUTHEASTERN COUNTIES KEEPING A CHANCE OF RAIN AFTER MIDNIGHT. COMPARED TO YESTERDAY...MODELS NOW SHOW THE COLD FRONT MOVING FAR ENOUGH SOUTH OF THE REGION TO KEEP SOUTHERN COUNTIES WITH A DRY FORECAST ON TUESDAY. MEANWHILE...TO THE NORTH...AN UPPER LEVEL LOW WILL MAKE SLOW PROGRESS TO THE EAST...PASSING FROM ONTARIO INTO QUEBEC. MODELS HAVE ALSO COME INTO LINE KEEPING MOST PRECIPITATION WITH TUESDAYS SHORTWAVE TO THE NORTH OF THE REGION...ALTHOUGH A COUPLE OF SHOWERS COULD CLIP NORTHERN COUNTIES. AFTER A DRY TUESDAY NIGHT...LOW PRESSURE FROM THE CENTRAL PLAINS WILL MOVE EAST ON WEDNESDAY. TEMPERATURES WILL REMAIN AROUND SEASONAL NORMS THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... THERE IS GOOD AGREEMENT IN THE LONG TERM FORECAST AS AN UPPER TROUGH REMAINS PARKED OVER THE EASTERN US. SEVERAL WAVES RIDING THROUGH THE UPPER FLOW WILL MAINTAIN THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD...WITH OVERALL BETTER CONSENSUS BETWEEN THE GFS AND ECMWF THAN IN THE PREVIOUS DAYS RUNS. WITH THE TROUGH PROGGED TO DEEPEN BY NEXT WEEKEND...EXPECT TEMPERATURES TO TREND A FEW DEGREES COOLER THAN SEASONAL AVERAGES IN NORTHERLY FLOW. && .AVIATION /23Z SUNDAY THROUGH FRIDAY/...
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EXPECTING VFR CONDITIONS TO PREVAIL THROUGH THE NIGHT AND INTO MONDAY...ALTHOUGH HIGH PRESSURE WILL BEGIN SLIPPING TO THE EAST AS A COLD FRONT APPROACHES THE REGION. TIMING THE FRONT ACROSS THE FORECAST AREA AROUND MIDDAY MONDAY...GIVING RISE TO SHOWER AND THUNDERSTORM ACTIVITY ALONG AND AHEAD OF IT. ANY RESTRICTIONS THROUGH THE TAF PERIOD WILL BE BREIF AND ASSOCIATED WITH THESE SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY APPROACH SEVERE CRITERIA WITH STRONG WIND BEING THE MAIN THREAT. OUTSIDE OF THUNDERSTORMS...LIGHT SURFACE WINDS WILL INCREASE AGAIN FROM THE SOUTHWEST MONDAY MORNING...WITH A WIND SHIFT EXPECTED TO THE WEST- NORTHWEST AS THE FRONT PASSES. TAX OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... THE NEXT CHANCE FOR RESTRICTIONS IS EXPECTED WITH A THURSDAY UPPER DISTURBANCE.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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