Area Forecast Discussion
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000 FXUS61 KPBZ 252148 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 548 PM EDT SAT OCT 25 2014 .SYNOPSIS... AFTER A SLIGHT COOL DOWN FOR SUNDAY...TEMPERATURES WILL WARM WELL ABOVE NORMAL MONDAY AND TUESDAY. A COLD FRONT TUESDAY NIGHT WILL BRING RAIN AND A RETURN TO COLDER TEMPERATURES. && .NEAR TERM /THROUGH SUNDAY/... A WEAK COLD FRONTAL BOUNDARY IS CURRENTLY WORKING THROUGH THE WESTERN PORTIONS OF THE CWA EARLY THIS EVENING...WITH JUST A FEW CLOUDS MANAGING TO BE GENERATED AHEAD OF IT. A DEARTH OF LAYER MOISTURE IS EVIDENT WITH IT...AND GIVEN FAIRLY STRONG BOUNDARY LAYER DEWPOINT DEPRESSIONS AHEAD OF IT...EVEN THE LIFT ALONG THE FRONT WILL BE INSUFFICIENT TO GENERATE ANY RAIN SHOWERS AS IT PASSES. THAT SAID...STEEP LAPSE RATES AND STRONG MIXING AHEAD...ALONG..AND BEHIND THE FRONT ARE EVIDENT...AND GIVEN STRONG MOMENTUM IN THE LOWEST 5 KFT OF THE OVERNIGHT MODEL SOUNDINGS...IT WOULD SEEM SOME WIND GUSTS WILL BE LIKELY TO CONTINUE THROUGH THE FIRST PART OF TONIGHT. THE BIGGEST RAMIFICATION OF THE FRONTAL PASSAGE BEYOND THE WIND WILL LIKELY BE THE FALL IN DEWPOINTS. UPSTREAM DEWPOINT VALUES ARE RUNNING INTO THE 20S AND 30S...DOWN FROM THE LOWER 50S OVER THE REGION NOW. WHILE NEITHER SIDE OF THE FRONT IS MOIST...IT IS QUITE CERTAIN THAT VERY DRY AIR IS ON ITS WAY IN. AS A RESULT...SKIES WERE CLEARED OUT RAPIDLY WITH THE FRONTAL PASSAGE...AND WILL LIKELY REMAIN CLEAR THROUGH THE DAY ON SUNDAY. FRIES && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... HIGH PRESSURE ALONG THE EAST COAST WILL BRING FLOW WITH A SOUTHERLY COMPONENT...ALLOWING FOR TEMPERATURE TO RISE ABOVE NORMAL. NEARLY ALL LOCATIONS ARE EXPECTED TO REACH THE 70S ON TUESDAY AHEAD OF AN ADVANCING COLD FRONT. HAVE SPED UP ARRIVAL TIME OF PRECIP...AND HAVE NOW BROUGHT IN A CHANCE OF RAIN EVERYWHERE BY LATE TUESDAY AFTERNOON. 12Z GFS AND NAM BOTH SHOW SMALL AMOUNTS OF INSTABILITY IN ZANESVILLE SOUNDING...AND HAVE ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR PORTIONS OF OHIO. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... COLD FRONT WILL RACE ACROSS REGION TUESDAY NIGHT AND HAVE GONE WITH LIKELY POPS FOR SHOWERS WITH FRO PA AND UPPER LEVEL TROUGH. FAIRLY QUIET WEATHER FOR WEDNESDAY AND THURSDAY WITH WEAK SURFACE RIDGE STRETCHED ACROSS THE UPPER OHIO VALLEY. BY FRIDAY DEEPENING UPPER LEVEL SYSTEM AND DEVELOPING SURFACE LOW PRESSURE WILL BRING SHOWERS BACK TO THE REGION FOLLOWED BY MUCH COOLER CONDITIONS FOR THE START OF NEXT WEEKEND. && .AVIATION /22Z SATURDAY THROUGH THURSDAY/...
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GUSTY SOUTHWESTERLY WINDS WILL CONTINUE UNTIL MID EVENING BEFORE DECOUPLING AFTER FRONTAL PASSAGE TONIGHT. THERE IS SOME UNCERTAINTY IN HOW SOON WINDS WILL LESSEN AT THE SURFACE BUT FOR NOW REFLECT THIS OCCURRING SHORTLY AFTER MIDNIGHT AT MOST LOCATIONS. IF WINDS DECOUPLE EARLIER...LOW LEVEL IND SHEAR WILL BE A CONCERN AS LATEST RAP SOUNDINGS SHOW 40KTS AT 1KFT AGL BY MID EVENING. REMOVED MVFR CIGS FROM 18Z TAFS AS MUCH DRIER AIR WILL BE MOVING IN BEHIND THE COLD FRONT. MODELS ARE ALL IN VERY GOOD AGREEMENT SHOWING LIMITED LOW LEVEL MOISTURE...AND MODEL SOUNDINGS SHOW A LARGE ENOUGH MARGIN BETWEEN TEMPERATURE AND DEWPOINT PROFILES DESPITE THE COLD AIR ADVECTION BEHIND THE FRONT. OUTLOOK.../SUNDAY THROUGH THURSDAY/... VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH EARLY NEXT WEEK.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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