Area Forecast Discussion
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000 FXUS61 KPBZ 280541 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 141 AM EDT THU MAY 28 2015 .SYNOPSIS... WARM TEMPERATURES AND PERIODIC SHOWER AND THUNDERSTORM CHANCES ARE EXPECTED THROUGH THE REST OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... A WEAK VORT WILL RIDE NORTHEASTWARD IN DEEP SOUTHWESTERLY FLOW AHEAD OF THE MAIN SHORT WAVE TROUGH OVER THE CENTRAL GREAT LAKES THIS EVENING. THIS COMBINED WITH UPPER DIVERGENCE FROM THE RIGHT ENTRANCE REGION OF A NEARBY UPPER JET STREAK WILL ALLOW FOR SOME DEGREE OF LARGE SCALE ASCENT ALONG AN AXIS OF HIGH VERTICAL WIND SHEAR THAT EXTENDS FROM SOUTHWESTERN OHIO INTO NORTHWESTERN PENNSYLVANIA. ALONG AND AHEAD OF THIS AXIS...CAPE VALUES HAVE SURGED TOWARD 700-1200 J/KG ACROSS OUR AREA...AND MODEL PROJECTIONS INDICATE 0-6 KM BULK SHEAR WILL APPROACH 45 KTS ALONG AND NORTH OF I-80 THROUGH THE EVENING. RATHER BURLY DCAPE VALUES ARE ALSO PRESENT AHEAD OF ONGOING CONVECTOIN ACROSS NORTHERN OHIO AT THE MOMENT...SO A WIND THREAT SEEMS TO BE THE LARGEST CONCERN GOING INTO THE NEXT SEVERAL HOURS. HOWEVER...ONGOING CONVECTION HAS LARGELY ALREADY GUST OUT...WITH A QUITE DISCERNIBLE OUTFLOW BOUNDARY EVIDENT ON KPBZ WSR-88D...SO THE WIND THREAT WILL BE GENERALLY CONFINED NORTH OF PITTSBURGH...AND ANY SEVERE WIND IS EXTREMELY UNLIKELY AT THIS POINT. THE SURFACE BOUNDARY WILL FOLLOW THIS ACTIVITY THROUGH THE AREA OVERNIGHT TONIGHT MORNING. THIS WILL BRING PROGRESSIVELY DRIER AIR IN FROM THE NORTH AS SURFACE FLOW TURNS NORTHERLY. HOWEVER...LARGE SCALE FORCING FOR THE FRONTAL BOUNDARY WILL BE PEELING TO THE NORTHEAST...AND THE SURFACE HIGH BEHIND THE FRONT FAILS TO BUILD SOUTHEASTWARD. THIS WILL LIKELY LEAD TO THE FRONT NOT CLEARING THE ENTIRETY OF THE SOUTHERN PORTION OF THE AREA BY MORNING OR EVEN INTO THE DAYTIME ON THURSDAY. FRIES && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/... RIDGING IS PROGGED TO GRADUALLY BUILD IN THURSDAY...THOUGH A FEW SHOWERS/STORMS COULD LINGER INTO EARLY AFTERNOON ACROSS THE WV/MD RIDGES AS THE SOUTHERN PORTION OF THE WEAKENING SURFACE BOUNDARY CROSSES. MODEL PROGS HAVE SHIFTED THE RIDGE AXIS FURTHER EAST FOR FRIDAY...RESULTING IN A QUICKER RETURN TO SOUTHWEST FLOW WITH A WEAK EMBEDDED CROSSING SHORTWAVE. INCLUDED CHANCE POPS FOR AFTERNOON SHOWERS/STORMS. MOIST SOUTHWEST FLOW IS EXPECTED TO CONTINUE THROUGH SATURDAY AS A COLD FRONT ADVANCES ACROSS THE GREAT LAKES REGION...BRINGING INCREASING POPS THROUGH THE DAY. TEMPERATURES ARE EXPECTED TO CONTINUE AROUND 10 DEGREES ABOVE SEASONAL LEVELS USING THE LATEST GRIDDED MOS AND SREF NUMBERS. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... CHANGES TO THE EXTENDED FORECAST WERE TO TEMPERATURES AND POPS MAINLY INTO MONDAY TO BE IN BETTER COORDINATION WITH SURROUNDING OFFICES AND NEW WPC PROGS. COLD FRONT WILL CROSS REGION AND STALL ACROSS THE CENTRAL APPALACHIANS SUNDAY NIGHT. LIKELY POPS ACROSS THE REGION SATURDAY NIGHT DIMINISHING WEST TO EAST DURING THE DAY SUNDAY. TEMPERATURES WERE LOWERED WITH FROPA AND COOL HIGH PRESSING NOSING SOUTH FROM THE GREAT LAKES INTO MONDAY. HOW FAST STALLED BOUNDARY SHIFTS NORTH AS A WARM FRONT MAIN PROBLEM INTO MID WEEK. FOR NOW STAYED CLOSE TO WPC PROGS...WITH LITTLE CHANGE FROM PREVIOUS FORECAST. && .AVIATION /06Z THURSDAY THROUGH MONDAY/...
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SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE TO TRACK NORTH OF PIT DURING THE PREDAWN HOURS...AHEAD OF A WEAKENING COLD FRONT. MVFR/BRIEF IFR CIGS/VSBY WILL BE POSSIBLE AT FKL/DUJ THROUGH 09Z. THE FRONT WILL SAG SOUTHWARD...COMING TO A REST NEAR A ZZV/MGW LINE. A BRIEF PERIOD OF MVFR CIGS IS POSSIBLE ALONG/BEHIND THE FRONT TOWARD SUNRISE. EXPECT THESE TO MIX INTO A CU DECK BY LATE MORNING. FROM THERE...DRIER AIR WORKS IN FROM THE NORTH...AND VFR CONDITIONS ARE FORECAST FOR THE AFTERNOON AND EVENING HOURS. LIGHT WINDS WILL SWING THROUGH NORTH TO NORTHEAST WITH TIME. CL .OUTLOOK.../THURSDAY NIGHT MONDAY/... RESTRICTIONS POSSIBLE IN SCT THUNDERSTORMS FRIDAY...WITH MORE WIDESPREAD RESTRICTIONS EXPECTED SATURDAY INTO SUNDAY.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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