Area Forecast Discussion
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000 FXUS61 KPBZ 291721 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 121 PM EDT FRI APR 29 2016 .SYNOPSIS... LOW PRESSURE WILL MAINTAIN CLOUDY SKIES WITH SHOWER CHANCES TODAY. THE NEXT SYSTEM WILL BRING WIDESPREAD RAIN LATER SATURDAY AND INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... STAGNANT COOL AND MOIST AIR MASS WILL CONTINUE TO PLAGUE THE AREA THROUGH TONIGHT. SOME EROSION OF LOW STRATUS IS DEVELOPING ON THE SOUTHERN FLANK...ALLOWING FOR SCATTERING AND WARMING SOUTH OF THE MASON-DIXON LINE. THIS WILL AGAIN SET UP A SHARP GRADIENT IN TEMPERATURES THIS AFTERNOON WITH NORTHERN WEST VIRGINIA GETTING INTO THE UPPER 60S...WHILE NORTH OF I-80 MAY TOUCH 50 DEGREES. SHORTWAVE TROUGH AXIS CURRENTLY CROSSING LAKE ERIE WILL SKIRT THE NORTHERN HALF OF THE FORECAST AREA THIS AFTERNOON. EXPECT CURRENT SHOWER ACTIVITY TO BLOSSOM NORTH OF PITTSBURGH IN RESPONSE TO THE QUICK PASSING WAVE. ADDITIONALLY...HI-RES CAMS SHOW SHOWERS DEVELOPING JUST SOUTH OF PITTSBURGH. GIVEN THE STEEPENING LOW- LEVEL LAPSE RATES...LIFT FROM THE WAVE AND COPIOUS MOISTURE...THINK THAT CHANCE POPS THROUGH AND SOUTH OF THE PITTSBURGH METRO AREA SEEM PRUDENT. WAVE PASSES TO THE EAST TONIGHT AND SOME DRYING WILL OCCUR. MOISTURE WILL BEGIN TO ERODE FROM THE WEST...SCATTERING OUT THE LOW CLOUDS...BUT TIMING IS DIFFICULT TO PIN DOWN AT THIS POINT. LOW TEMPERATURES WILL DEPEND LARGELY ON TIMING AND EXTENT OF CLEARING OVERNIGHT. WITH THIS IN MIND...HAVE WESTERN PORTIONS OF THE FORECAST AREA RELATIVELY LOW COMPARED TO EASTERN PORTIONS. TAX && .SHORT TERM /SATURDAY THROUGH SUNDAY/... A FEW SHOWERS MAY LINGER IN THE EAST THIS EVENING AS UPPER LEVEL ENERGY QUICKLY MOVES TOWARD SOUTHEASTERN PA. HUNG ON TO CLOUDS THROUGH THE NIGHT...PARTICULARLY OVER THE EASTERN HALF OF THE AREA...AS MODELS ARE SHOWING LOW AND MID-LEVEL MOISTURE BECOMING TRAPPED UNDER THE RISING HEIGHTS ALOFT. UPPER LEVEL HEIGHTS WILL CONTINUE TO RISE SATURDAY IN RESPONSE TO DEEPENING SYSTEM OVER THE CENTRAL PLAINS. THIS WILL ALLOW FOR A BREAK IN THE ACTIVITY FOR A PORTION OF SATURDAY. SHOWERS WILL BEGIN TO OVERSPREAD THE WESTERN HALF OF THE AREA SATURDAY AFTERNOON AND THEN THE REST OF THE AREA BY EVENING. STILL SEEING SOME TIMING DIFFERENCES WITH THE SHOWERS...BUT IT DOES SEEM THAT MODELS ARE SPEEDING UP THEIR ONSET. TEMPERATURE INCREASES SATURDAY...AS WARMER AIR MOVES IN AHEAD OF THE AFOREMENTIONED SYSTEM. SHOWERS WILL CONTINUE INTO SUNDAY...BUT AGAIN...DIFFERENCES IN OPERATIONAL MODEL DATA WITH THE SPEED AND LOCATION OF THE SURFACE LOW...MAKE FOR A LOW CONFIDENCE FORECAST. WILL RELY ON THE SUPERBLEND HERE TO ATTEMPT TO OVERCOME MODEL DISCREPANCIES. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... SHOWER COVERAGE WILL DECREASE SUNDAY NIGHT/EARLY MONDAY AS THE ENTIRE SYSTEM MOVES OFF THE EAST COAST. A DRY PERIOD APPEARS LIKELY TUESDAY AND POSSIBLY INTO WEDNESDAY. THERE CONTINUES TO BE UNCERTAINTY WITH THE TIMING/DEPTH OF A DEVELOPING EASTERN TROUGH FROM WEDNESDAY ON...AS A WESTERN RIDGE ELICITS A RESPONSE DOWNSTREAM. CHANCE POPS APPEAR WISE FOR A PORTION OF WEDNESDAY AND INTO THURSDAY AS THE POTENTIAL FOR SHOWERS INCREASES. USED SUPERBLEND FOR THE LONG TERM AS WELL. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... IFR RESTRICTIONS GRADUALLY IMPROVING TO LOW MVFR...PRIMARILY SOUTH OF PITTSBURGH WHERE SOME SCATTERING IS NOTED ON SATELLITE. ANOTHER SHORTWAVE TROUGH WILL PASS ACROSS THE NORTH THIS EVENING...REINFORCING THE LOW CIGS ACROSS THE NORTH. THIS WAVE WILL ALSO GENERATE ADDITIONAL LIGHT RAIN SHOWERS...MAINLY FOR NORTHERN AND EASTERN PORTS. HIGH CONFIDENCE IN IFR CONDITIONS REOCCURRING TONIGHT...BUT AFTER THE PASSAGE OF THE WAVE...LOWER-LEVELS BEGIN TO DRY OUT FROM THE WEST. THIS WILL RESULT IN SOME AMOUNT OF SCATTERING/CLEARING FROM KZZV EASTWARD NEAR DAYBREAK SATURDAY. CONFIDENCE IS MUCH LOWER ON THE AMOUNT AND EXACT TIMING OF THE IMPROVEMENT NEAR SUNRISE. VFR CONDITIONS ARE THEN EXPECTED FROM SATURDAY MID-MORNING THROUGH THE DURATION OF THE OPERATIONAL TAF PERIOD. LIGHT WEST WINDS WILL VEER TO THE NORTHWEST TONIGHT IN THE WAKE OF THE PASSING WAVE. LIGHT NORTH WINDS TONIGHT WILL THEN VEER TO EASTERLY SATURDAY. WIND SHOULD GENERALLY STAY 10KTS OR LESS THROUGH THE PERIOD. TAX .OUTLOOK /FRIDAY NIGHT THROUGH TUESDAY/... RESTRICTIONS ARE LIKELY AGAIN LATE SATURDAY THROUGH SUNDAY NIGHT AS LOW PRESSURE CROSSES THE REGION. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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