Area Forecast Discussion
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000 FXUS61 KPBZ 011754 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 154 PM EDT SUN MAY 1 2016 .SYNOPSIS... A COUPLE OF LOW PRESSURE SYSTEMS WILL PROVIDE RAIN OVER THE REGION INTO EARLY MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE FIRST SURFACE WAVE ALONG A QUASI-STATIONARY BOUNDARY HAS PUSHED EAST OF THE THE AREA...TAKING WITH IT THE BULK OF THE DEEP MOISTURE AND LARGE SCALE LIFT. IN ITS WAKE...VIRTUALLY NIL BOUNDARY LAYER ADVECTION EXISTS...THUS SOUPY DEWPOINTS NEAR 60F REMAIN. HOWEVER...SUBSTANTIAL MID-LEVEL DRYING IS EVIDENT ON WATER VAPOR IMAGERY AND THE FIRST FEW FRAMES OF VISIBLE IMAGERY INDICATE SOME DEGREE OF CLEARING CREEPING UP INTO CENTRAL OHIO AND NORTHERN WEST VIRGINIA AT THIS HOUR. AS THE DAY GOES ON...HRRR PROJECTIONS SUGGEST THIS SHOULD ENCROACH UPON MORE OF THE AREA...WHILE SYNOPTIC MODELS ARE NOT AS BULLISH WITH THIS IDEA. GIVEN BOUNDARY LAYER MOISTURE...IT WOULD SEEM SUNSHINE SHOULD BE DESTRUCTIVE IF CLEARING DOES OCCUR...SO WILL JUST TREND THE FORECAST TOWARD PARTLY/MOSTLY CLOUDY FOR A TIME. WITH SOME CLOUD BREAKUP AND INSOLATION GOING INTO THE AFTERNOON...LAPSE RATES SHOULD BECOME MORE UNSTABLE. COMBINING THIS WITH ADDITIONAL MID-LEVEL DRY AIR AND MODEST SHEAR WILL MEAN AN INCREASE IN INSTABILITY BY AFTERNOON AND EVENING AS A SECONDARY SURFACE WAVE APPROACHES. THUS POPS FOR SHOWERS AND THUNDERSTORMS WILL SECONDARILY INCREASE BY LATE AFTERNOON AND INTO THE EVENING HOURS. SPC STILL OUTLINES MUCH OF THE AREA IN A MARGINAL RISK FOR SEVERE WEATHER...HOWEVER WE WILL LIKELY NEED TO SEE MORE BREAKS THAN ARE EVIDENT AT THIS HOUR FOR THIS EVENTUALITY TO OCCUR. FRIES && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE FRONT WILL FINALLY TRACK SOUTHEASTWARD TONIGHT AS THE MAIN SHORTWAVE TROUGH PUSHES INTO NORTHERN OHIO. WITH THE LAGGING FRONTAL BOUNDARY CROSSING THE AREA...HAVE INCREASED POPS AGAIN OVERNIGHT. IT WILL TAKE ALL NIGHT AND PART OF MONDAY MORNING...BUT THE BOUNDARY WILL FINALLY EXIT TO THE SOUTHEAST... ENDING THE RAIN THREAT. A DIGGING UPPER LEVEL TROUGH OVER THE NORTHEAST WILL HELP SUPPORT A LOW PRESSURE SYSTEM ALONG THE EAST COAST. LOW CONSENSUS IN MODEL SOLUTIONS WILL REQUIRE A BLEND OF DATA FOR THE TUESDAY FORECAST. WILL NEED TO CONTINUE WITH THE THREAT FOR SHOWERS TUESDAY AS THE TROUGH CROSSES THE REGION. TEMPERATURES TUESDAY ARE EXPECTED TO BE A BIT BELOW NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... MODELS COMING INTO BETTER AGREEMENT THAT A LARGE TROUGH WILL SETUP OVER THE EASTERN CONUS DURING THE PERIOD. THIS WILL KEEP THE AREA COOL AND UNSETTLED INTO THE WEEKEND. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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LOW CLOUDS ARE RAPIDLY BREAKING UP AS DIURNAL MIXING INCREASES. WITH A VERY WEAK CAP HOLDING BACK INSTABILITY...INSOLATION WILL ALLOW FOR RAPID DEVELOPMENT OF SCATTERED SHOWERS AND THUNERSTORMS. GIVEN THE SOUPY AIR MASS...THESE WILL POP VIRTUALLY ANYWHERE IN THE AREA THROUGH THE AFTERNOON. MORE ORGANIZED SHOWERS AND WIDESPREAD RESTRICTIONS WILL ENCROACH LATER THIS EVENING AND OVERNIGHT AS A FINAL WAVE MOVES DOWN THE STATIONARY BOUNDARY ACROSS THE AREA. IFR CONDITIONS WILL BE LIKELY AT MOST SITES INTO MONDAY MORNING. .OUTLOOK /MONDAY THROUGH THURSDAY/... ANOTHER ROUND OF RESTRICTIONS IS LIKELY WITH A WEDNESDAY COLD FRONT.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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