Area Forecast Discussion
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000 FXUS61 KPBZ 300936 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 536 AM EDT SAT MAY 30 2015 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL CONTINUE OVER THE REGION UNTIL THE PASSAGE OF A STRONG COLD FRONT LATE SUNDAY. MUCH COOLER WEATHER WILL SETTLE OVER THE REGION TO START THE NEW WORK WEEK. && .NEAR TERM /THROUGH SUNDAY/...
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WHILE FAIRLY SOUPY DEWPOINTS REMAIN OVER THE AREA THIS MORNING...THERE IS SEEMINGLY LITTLE CHANCE IN THAT AIR MASS RESULTING IN WIDESPREAD DEVELOPMENT OF SHOWERS OR THUNDERSTORMS IN ANY QUICK FASHION. A SPRAWLING UPPER ANTI-CYCLONE IS USING OUR AREA AS A CUSHION EARLY THIS MORNING...WHICH MEANS ANY UPWARD MOTION IS BEING SUMMARILY SQUASHED. THIS UPPER ANTI-CYCLONE WILL EVER-SO-SLOWLY EEK EASTWARD THROUGH THE MORNING...WHICH WILL RESULT IN INCREASING SOUTHWESTERLY FLOW THROUGH BY AFTERNOON. THIS WILL INCREASE LOW LEVEL MIXING...RESULTING IN A SLIGHT DOWNWARD TICK IN DEWPOINTS AS A BIT OF DRIER AIR ALOFT IS ENTRAINED...AND ALSO DRIVE TEMPERATURES UPWARD DECIDEDLY THIS AFTERNOON. WITH SOUTHWESTERLY FLOW INCREASING INTO THE AFTERNOON...LAYER TEMPERATURES ALL INCREASE...WITH THE INCREASES AROUND 12-15 KFT BEING THE MOST NOTABLE. IN FACT...IT SEEMS BY AFTERNOON THAT CAPE WILL BECOME INCREASINGLY DIFFICULT TO MUSTER ABOVE THE FREEZING LAYER. WHAT CAPE THERE IS LOOKS TO BECOME HIGHLY SKINNY...AND EVEN WITH STRONG LOW LEVEL LAPSE RATES AND SOME SHEAR...SUSTAINED UPDRAFTS WILL BE TOUGH TO MANAGE GIVEN A NOTICEABLE LACK OF A LIFTING MECHANISM AS THE WARM FRONT THAT LIFTED NORTHWARD ACROSS THE AREA YESTERDAY WILL BE PARKED WELL TO OUR NORTH ACROSS THE GREAT LAKES. THAT SAID...WITH TEMPERATURES SKYROCKETING INTO THE 80S AND DEWPOINTS STILL LINGERING IN THE LOWER 60S WITH DECENT SHEAR...A HIT OR MISS DISORGANIZED SHOWER OR THUNDERSTORM CANNOT BE RULED OUT...HOWEVER POPS WERE ROLLED BACK FROM PREVIOUS FORECASTS. WITH STRONG LOW LEVEL LAPSE RATES...AND DECENT SHEAR...ALONG WITH SOME MID-LEVEL DRY AIR...ANY STORMS THAT DO DEVELOP MAY BE ABLE TO MANAGE SOME GUSTY WINDS AS WELL. THE FAIRLY DEEP UPPER WAVE CURRENTLY OVER EASTERN TEXAS WILL SLOWLY WANDER ITS WAY UP TOWARD THE AREA FOR SUNDAY. HOWEVER...BEFORE IT DOES...DIURNAL DEVELOPMENT FROM SATURDAY AFTERNOON WILL LIKELY DIE...YIELDING A MOSTLY DRY/WARM/HUMID SATURDAY NIGHT...AND A VERY WARM START TO SUNDAY. HEIGHTS LOOK TO FALL AGGRESSIVELY BY SUNDAY HOWEVER...WITH A VERY SHARP SHORT WAVE TROUGH SET TO MOVE THROUGH THE AREA ALONG WITH A NICE RIGHT ENTRANCE OF AN UPPER JET STREAK. THIS SHOULD YIELD A PERIOD OF SHOWERS AND THUNDERSTORMS AS THE OCCLUDING UPPER WAVE MOVES THROUGH THE REGION. SOME MODEL SOLUTIONS PROJECT A STRONG TROP FOLD IS ASSOCIATION WITH THIS SYSTEM THAT WOULD ALLOW FOR STRONG MID-LEVEL DRYING AND DEEP MIXING BY LATE SUNDAY. SHOULD THIS OCCUR...SHOWERS WOULD LIKELY QUICKLY WIND DOWN...WITH A FAIRLY WINDY PERIOD IN STORE BY THE END OF THE DAY. AT THE MOMENT...THE FORECAST WAS TRENDED TO END PRECIPITATION A BIT MORE ABRUPTLY...HOWEVER MODEL AGREEMENT WAS NOT SUCH TO ENTIRELY REMOVE CHANCES BY LATE SUNDAY. MODEL AGREEMENT WAS STRONG ENOUGH TO REALLY INCREASE HIGH TEMPERATURES SUNDAY...THOUGH...AS STRONG MIXING AND A VERY WARM START TO THE DAY WILL LIKELY ALLOW FOR MANY AREAS TO AGAIN JUMP INTO THE 80S. FRIES
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&& .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... SURFACE LOW DIRECTLY OVERHEAD SUNDAY NIGHT VERTICALLY TILTED BACK TOWARDS THE THUMB OF MICHIGAN. PLACEMENT OF THE MID-LEVEL LOW IS FAVORABLE FOR THE DRY SLOT...CLEARLY EVIDENT ON MID-LEVEL MODEL RH FIELDS...TO MOVE IN LATE SUNDAY EVENING AND SQUASH WIDESPREAD PRECIPITATION. MID-LEVEL LOW SHIFTS NORTHEAST OF THE AREA IN THE PRE-DAWN HOURS MONDAY...ALLOWING STRONG COLD AIR ADVECTION TO INVADE THE AREA...SETTING A COOLER TONE TO THE NEW WORK WEEK. 00Z GFS HAS 850MB TEMPERATURES DROPPING ABOUT 1C/HR TO 5-7C BY DAWN MONDAY. THIS STEEPENS THE LOW-LEVEL LAPSE RATES AND TRAPS COPIOUS LOW-LEVEL MOISTURE UNDER AN INVERSION NEAR 800MB. STRATO-CU WILL BE STUBBORN MIXING OUT MONDAY...HOLDING FOR MOST OF THE DAY. MOISTURE DEPTH WONT BE CONDUCIVE FOR MUCH PRECIPITATION DEVELOPMENT MONDAY...BUT DEEPER MOISTURE OVER THE HIGH TERRAIN OF MD/WV/PA DOES WARRANT THE NEED FOR CHANCE POPS. CURRENT FORECAST CALLS FOR TEMPS A FEW NOTCHES BELOW AVERAGE. UPPER-LEVEL LOW DEEPENS AND CUTS OFF NORTH OF LAKE HURON MONDAY EVENING. THIS WILL WORK TO QUICKLY LIFT THE REMAINING MOISTURE ASSOCIATED WITH THE MID-LEVEL LOW NORTH AND OUT OF THE AREA. THE FLUSHING MECHANISM OF THE UPPER-LOW WILL PAVE THE WAY FOR DRIER AIR TO MOVE IN WITH A BUILDING SURFACE HIGH. TUESDAYS HIGH TEMPERATURES WILL RECOVER NICELY WITH MORE SUN EXPECT THAN MONDAYS OFFERING...BUT COOL NORTHWEST FLOW ALOFT MEANS A RETURN TO WELL-ABOVE NORMAL TEMEPRATURES IS NOT ANTICIPATED FOR TUESDAY. TAX && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... BROAD SURFACE HIGH ENCAPSULATES THE AREA BY MID-WEEK KEEPING PRECIPITATION NON-EXISTENT AND CLOUD COVER LOW. SUBSIDENCE IS FURTHER BOLSTERED BY THE ARRIVAL OF THE UPPER RIDGE THURSDAY. THIS MEANS THAT A GRADUAL WARMING TREND IS EXPECTED WITH TEMPERATURES ONCE AGAIN RETURNING TO WELL-ABOVE AVERAGE. THE NEXT REAL PRECIPITATION CHANCE WILL COME WITH AN UPPER-LEVEL WAVE POISED TO ARRIVE LATE NEXT WEEK. TAX && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE DAY UNLESS ANY ISOLATED THUNDER DEVELOPS OVER A SITE THIS AFTERNOON. .OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/... RESTRICTIONS WILL BE POSSIBLE WITH THE PASSAGE OF A SYSTEM ON SUNDAY AND SUNDAY EVENING. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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