Area Forecast Discussion
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000 FXUS61 KPBZ 011923 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 323 PM EDT MON JUN 1 2015 .SYNOPSIS...
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AN UPPER LEVEL LOW WILL NEARLY STALL OVER THE OHIO AND TENNESSEE VALLEYS THROUGH MIDWEEK...WITH RAINFALL CHANCES MAINLY SOUTH OF PITTSBURGH. TEMPERATURES WILL SHOW A SLOW WARMING TREND.
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&& .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... COLD FRONT WILL MAIN SITUATED JUST SOUTH OF THE FORECAST AREA THROUGH THE PERIOD AS DEEP UPPER TROUGH APPROACHES. WHILE THE LOW WILL EVENTUALLY BE CUT OFF FROM THE UPPER LEVEL FLOW...MOISTURE IN ADVANCE OF THIS SYSTEM HAS MADE IT WELL INTO OHIO THIS AFTERNOON...WHICH WAS NOT HANDLED WELL BY THE DETERMINISTIC GUIDANCE. HAVE UPPED POPS SLIGHTLY FOR THE SOUTHERN HALF OF THE FORECAST AREA TO BETTER REFLECT CURRENT RADAR TRENDS BUT MOST OF THE GUIDANCE STILL SUGGESTS THAT THE AREA OF PRECIP SHOULD DIMINISH AS THE LOW CUTS OFF THIS EVENING. THE EXCEPTION WILL BE ALONG THE COLD FRONT...WHERE THE RAP AND THE HRRR MAINTAIN QPF THROUGH MUCH OF THE NIGHT. WHILE THE BULK OF THE HEAVIEST PRECIP SHOULD REMAIN SOUTH OF ALL OF OUR COUNTIES...A FEW THUNDERSTORMS ARE POSSIBLE OVER TUCKER AND GARRETT WHERE BREAKS IN THE CLOUDS HAVE ALLOWED FOR SOME DESTABILIZATION. CLOUD COVER AND PRECIP SHOULD KEEP TEMPERATURES FROM FALLING OFF TOO MUCH OVERNIGHT. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
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CUTOFF UPPER LOW WILL SLOWLY DRIFT ACROSS THE OHIO AND TENNESSEE VALLEYS DURING THIS PERIOD...AND WILL SLOWLY FILL AS IT APPROACHES THE APPALACHIANS BY THURSDAY. MODELS ARE IN GOOD AGREEMENT WITH THIS THINKING. AT THE SURFACE...HIGH PRESSURE WILL BE MAKING AN EASTWARD TRACK TO OUR NORTH...BEFORE EXITING THE NEW ENGLAND COAST ON THURSDAY. THIS WILL HELP TO KEEP THE BULK OF MOISTURE SUPPRESSED TO OUR SOUTH. SHRA COVERAGE WILL BE DECREASING DURING THE MORNING AS FRONTAL WAVE EXITS...WITH ONLY THE SOUTHEAST RIDGES HANGING ON TO ISOLATED SHRA INTO THE AFTERNOON. ANOTHER SPOKE OF VORTICITY WILL ROTATE AROUND THE UPPER LOW TUESDAY NIGHT AND BRING AN INCREASE IN COVERAGE WITH TIME..CONFINED TO AREAS SOUTHEAST OF PIT THROUGH TUESDAY NIGHT. SCATTERED SHRA WILL THEN EXPAND TO AN AREA SOUTH OF A PHD-LBE LINE ON WEDNESDAY. ALL OF THIS ACTIVITY WILL BE LIGHT. DESPITE MOISTURE CONTENT/PWATS INCREASING ON WEDNESDAY...SOUTHEAST FLOW WILL ADD A DOWNSLOPING COMPONENT WHICH WILL HELP TO SUPPRESS PRECIP TOTALS. BY THURSDAY...LOW LEVEL FLOW WEST OF THE RIDGES TURNS MORE SOUTHERLY AS THE UPPER LOW TRACKS TO OUR SOUTH AND A RETURN FEED SETS UP BEHIND THE NEW ENGLAND HIGH CENTER. THIS WILL ALLOW BETTER INSTABILITY TO RETURN...AND SHOWER CHANCES ARE IN THE FORECAST CWA- WIDE. ALSO REINTRODUCED THUNDER CHANCES ON THIS DAY WITH SOME DEEPER CAPE PROFILES STARTING TO SHOW UP ON SOUNDINGS. ACTIVITY WILL DIURNALLY DECREASE TOWARDS THURSDAY EVENING. A SLOW WARMING TREND WILL BE SEEN IN TEMPERATURES...WITH READINGS GETTING BACK ABOVE NORMAL BY THURSDAY. GENERALLY KEPT NUMBERS IN LINE WITH MODEL CONSENSUS.
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&& .LONG TERM /FRIDAY THROUGH MONDAY/...
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ANOTHER ROUND OF DIURNAL SHRA/TSRA IS PICTURED FOR FRIDAY AS THE UPPER LOW CONTINUES TO DEGRADE AND LIFT OUT. A COLD FRONT WILL APPROACH LATER FRIDAY NIGHT OR SATURDAY. THIS MAY LEAD TO A BRIEF BREAK IN THE UNSETTLED PATTERN BUT THIS IS STILL UNCERTAIN...AND PRECIPITATION CHANCES REMAIN IN THE FORECAST FOR SUNDAY AND MONDAY.
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&& .AVIATION /19Z MONDAY THROUGH SATURDAY/... IFR CONDITIONS SHOULD GRADUALLY IMPROVE TO MVFR THROUGH THIS AFTERNOON...HOWEVER ARE UNLIKELY TO GO ABOVE 3KFT WITH MOISTURE TRAPPED UNDER INVERSION AND VERY LITTLE MIXING TO SCATTER OUT OR LIFT THE CLOUD DECK. SHORTWAVE MAY BRING A PERIOD OF SHRA TO SEVERAL TAF SITES SOUTH OF PIT THIS EVE WHICH COULD SUPPORT PROLONGED MVFR/IFR CONDITIONS OVERNIGHT DESPITE MODEL GUIDANCE SAYING OTHERWISE. FOR NOW...WILL MAINTAIN THE PESSIMISTIC TREND WITH MVFR CIGS CONTINUING. .OUTLOOK.../TUESDAY THROUGH FRIDAY/... CONDITIONAL RESTRICTIONS ARE POSSIBLE THROUGH MIDWEEK WITH CUTOFF UPPER LOW SITUATED JUST SOUTH OVER TENNESSEE. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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