Area Forecast Discussion
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000 FXUS61 KPBZ 291743 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 143 PM EDT SUN MAR 29 2015 .SYNOPSIS...
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A WEAK SYSTEM WILL BRING RAIN AND SNOW OVERNIGHT INTO MONDAY.
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&& .NEAR TERM /THROUGH MONDAY/...
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CURRENT SATELLITE IMAGERY SHOWING CLEAR SKIES ACROSS THE REGION AS HIGH PRESSURE BEGINS TO PUSH SOUTHEAST OF THE AREA. SOUTHERLY FLOW IS EXPECTED TO INCREASE THROUGH THE EVENING AS THE CENTER OF THE HIGH MOVES EAST AND THE PRESSURE GRADIENT TIGHTENS. THIS SHOULD HELP ACCELERATE FURTHER WARMING DURING THE LATE AFTERNOON/EARLY EVENING HOURS. TONIGHT...A RELATIVELY DRY AND WEAK SYSTEM WILL MOVE THROUGH THE WESTERN GREAT LAKES AND INTO OUR WEST. AS THE MAIN TROF AXIS ENTERS...A WEAK WARM FRONT WILL LIFT JUST INTO THE SOUTHERN EXTENT OF THE FORECAST AREA...KEEPING TEMPERATURES ACROSS THE SOUTHERN HALF OF OUR COUNTIES ELEVATED. TIMING ACROSS MODEL GUIDANCE HAS BEEN FAIRLY CONSISTENT...BUT THE LATEST RUNS PUSH TIMING BACK AN HOUR OR TWO AS IT FIGHTS THE DRY AIR FIRMLY ENTRENCHED. EXPECTING A SUPPRESSED DIURNAL TEMPERATURE TREND...AS WARM AIR TRIES TO PUSH NORTHWARD THROUGH THE OVERNIGHT INTO THE EARLY HOURS MONDAY. PREDOMINANT PRECIPITATION TYPE NEAR PITTSBURGH AND SOUTH IS EXPECTED TO BE RAIN...BUT AREAS NORTH OF PITTSBURGH WILL COOL ENOUGH TO TRANSITION THE PRECIPITATION FROM RAIN TO A RAIN/SNOW MIX. MODEL SOUNDINGS NORTH OF I-80 INDICATE THIS AREA HAS THE BEST CHANCE TO SEE ALL SNOW. REGARDLESS OF PRECIPITATION TYPE...WITH ONLY MODEST FORCING AND OVERUNNING OF MID- AND UPPER- LEVEL MOISTURE...PRECIPITATION RATES SHOULD BE LOW. LITTLE...IF ANY...SNOW ACCUMULATION IS EXPECTED THROUGH MONDAY MORNING. STRATIFORM PRECIPITATION WILL QUICKLY DWINDLE QUICKLY WEST TO EAST AFTER SUNRISE MONDAY. THIS IS DUE TO THE DEEPER MOISTURE EVACUATING THE AREA...LEAVING ONLY MODEST RESIDUAL LOW-LEVEL MOISTURE. FORECAST SOUNDINGS INDICATE THE POTENTIAL FOR PATCHY DRIZZLE THROUGH MIDDAY MONDAY...BUT CONFIDENCE NOT HIGH ENOUGH FOR INCLUSION AT THIS TIME. DEEPER MOISTURE WILL LINGER ALONG THE NORTH KEEPING LIGHT RAIN/SNOW POTENTIAL IN THROUGH MUCH OF THE DAY. CHANCES ACROSS THE NORTH WILL INCREASE AGAIN IN THE AFTERNOON AS COLDER MID-LEVEL AIR ASSOCIATED WITH AN UPPER-LEVEL WAVE ARRIVES. THIS WILL SUBSEQUENTLY STEEPEN THE LAPSE RATES AND DEVELOP CONVECTIVELY DRIVEN RAIN/SNOW SHOWERS. ELSEWHERE...CLOUDS COVER SHOULD SCATTER ENOUGH FOR POCKETS OF SUNSHINE AND WARMING. EXPECTING A PRONOUNCED GRADIENT OF HIGH TEMPERATURES MONDAY FROM NEAR 50 ACROSS THE SOUTH TO UPPER 30S NORTH. TAX
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&& .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/... AFTER A BRIEF BREAK...ANOTHER SHORTWAVE WILL QUICKLY BRUSH BY TO THE NORTH ON TUESDAY BUT SIMILAR TO THE PREVIOUS SYSTEM...SNOW WILL BE CONFINED MAINLY TO NORTHERN ZONES WITH AS THERE WILL ONLY BE A BRIEF PERIOD OF DEEPER MOISTURE TO WORK WITH. WEDNESDAY WILL BE DRY WITH SEASONAL TEMPERATURES AS HIGH PRESSURE BUILDS IN FROM THE WEST. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AS HIGH PRESSURE MOVES OFFSHORE WEDNESDAY NIGHT...A FRONT WILL APPROACH FROM THE WEST. WHILE 00Z GFS SLOWED THE ARRIVAL OF THE FRONT SOME FROM PREVIOUS MODEL RUNS...00Z ECMWF IS EVEN SLOWER THAN THAT. HOWEVER...WITH DECENT ENSEMBLE SUPPORT...WILL STICK WITH GFS TIMING AND BRING IN LIKELY POPS FOR THURSDAY NIGHT. HOWEVER...LOW PRESSURE FORMING ALONG THE COLD FRONT WILL KEEP PRECIPITATION IN THE FORECAST FRIDAY UNTIL IT MOVES INTO NEW ENGLAND SATURDAY. THURSDAY WILL EASILY BE THE WARMEST DAY OF THE WEEK...WITH MOST LOCATIONS REACHING THE 60S. TEMPS WILL DROP ABOUT 10 DEGREES EACH DAY...LEADING BACK TO YET ANOTHER PERIOD OF BELOW NORMAL VALUES. && .AVIATION /17Z SUNDAY THROUGH THURSDAY/...
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VFR CONDITIONS WILL PERSIST WITH NEARLY CLEAR CONDITIONS. HIGH CIRRUS BEGINNING TO PUSH IN THROUGH CENTRAL OHIO. A WEAK SYSTEM ENTERING THE REGION LATE THIS EVENING IS EXPECTED TO BRING PRECIPITATION TO ALL SITES. SOUTH AND WEST OF PITTSBURGH SHOULD REMAIN ALL RAIN...WITH SOME SNOW MIXING IN ELSEWHERE. CEILINGS WITH PRECIPITATION SHOULD INITIALLY BEGIN AS VFR...BUT ARE EXPECTED TO QUICKLY DROP TO MVFR. SOME MARGINAL LOW LEVEL WIND SHEAR MAY ALSO DEVELOP OVERNIGHT IF WINDS DECOUPLE...ESPECIALLY WEST OF PITTSBURGH...BUT DID NOT HAVE ENOUGH CONFIDENCE TO INCLUDE IN TAFS AT THIS TIME. SOME IMPROVEMENT WILL OCCUR MONDAY AFTER DAYBREAK WITH MOST LOCATIONS RETURNING BACK TO VFR AS THE FRONT PUSHES EAST. HOWEVER...DEEPER MOISTURE WILL LINGER ALONG OUR NORTH AND CONTINUE TO IMPACT FKL/DUJ. LINGERING RAIN/SNOW SHOWERS WILL BE REINVIGORATED BY THE UPPER-LEVEL LOW A IT SWINGS THROUGH MONDAY AFTERNOON NEAR THE END OF THE TAF PERIOD. TAX .OUTLOOK.../MONDAY THROUGH THURSDAY/... RESTRICTIONS ARE POSSIBLE ONCE AGAIN WITH CROSSING LOW PRESSURE TUESDAY AND THURSDAY.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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