Area Forecast Discussion
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000 FXUS61 KPBZ 201733 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 1233 PM EST SAT DEC 20 2014 .SYNOPSIS... BUILDING HIGH PRESSURE IS EXPECTED THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... SHORTWAVE TROUGH WILL SWING THROUGH THE OHIO VALLEY AND ACROSS THE CWA DURING THE EARLY PART OF THE NIGHT. EXPECTING CLOUD COVER TO BE MAINTAINED THROUGH THE PERIOD WITH AN OVERALL THIN BUT PERSISTENT MOISTURE LAYER A COUPLE THOUSAND FEET UP. WHILE MOISTURE IS OTHERWISE FAIRLY MEAGER AT PRESENT...SW FLOW AT H850 WILL HELP PUSH MARGINALLY BETTER PWAT VALUES INTO THE SOUTHERN COUNTIES BY SUNSET. THIS COMBINED WITH MODEST SUPPORT FROM SHORTWAVE MAY ALLOW A FEW SNOWFLAKES TO SQUEEZE OUT...SO ADDED A SLIGHT CHANCE POP TO THE GRIDS...MAINLY FOR THE EVENING...GENERALLY SOUTH OF A HLG/PIT/IDI LINE. ANY ACTIVITY SHOULD END SOON AFTER 06Z WITH SHORTWAVE DEPARTURE. TEMPERATURE FORECAST LOOKS DECENT OVERALL AT THIS TIME. && .SHORT TERM /SUNDAY THROUGH MONDAY/... MODELS ARE SHOWING SOME IMPROVEMENT SUNDAY...PARTICULARLY OVER THE WEST AND FAR SOUTH. HOWEVER...MODEL SOUNDINGS FOR THE REST OF THE REGION STILL WANT TO MAINTAIN A SATURATED LAYER AROUND 2500FT FOR MOST OF THE DAY...WHICH DOES NOT PRESENT MUCH HOPE FOR SUNSHINE. CLOUDS WILL BE TRICKY ON SUNDAY...TRYING TO DETERMINE HOW MUCH OF THE CLOUD DECK WILL BE ERODED. SPLIT FLOW DEVELOPS ON MONDAY WITH A LARGE SYSTEM TO THE WEST AND ANOTHER SYSTEM TO THE SOUTH-SOUTHEAST. IT APPEARS THAT THE AREA WILL LIE IN BETWEEN LIMITING THE CHANCES FOR PRECIPITATION. WAA WILL CONTINUE ON MONDAY AND LOW-LEVEL MOISTURE INCREASES ONCE AGAIN. LOOKS LIKE A GOOD DEAL OF CLOUD COVER AGAIN MONDAY. A WEAK AND UNORGANIZED SHORTWAVE TROUGH WILL SWING THROUGH MONDAY... ALLOWING FOR THE POSSIBILITY OF SOME LIGHT PRECIP...MAINLY OVER THE SOUTHERN RIDGES. THIS WILL NEED TO BE FINE TUNED AS THE WARMER AIR ALOFT MAY OCCUR BEFORE SURFACE TEMPS RESPOND. CONFIDENCE IS LOW THAT ANY PRECIP WILL OCCUR...SO FOR FORECAST WILL LEAVE OUT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... STILL SEEING SOME MINOR DIFFERENCES IN MEDIUM RANGE MODEL SOLUTIONS FOR MIDWEEK SYSTEM. THINK MUCH OF TUESDAY COULD BE DRY OR JUST LIGHT SHOWERS AS AREA WILL BE WELL INTO THE WARM SECTOR. RAIN WILL OVERSPREAD THE AREA TUESDAY NIGHT AHEAD OF OCCLUDED FRONT AND CONTINUE THROUGH WEDNESDAY. COLDER AIR WILL MOVE IN LATER WEDNESDAY NIGHT CHANGING ANY LINGERING SHOWERS TO SNOW SHOWERS. COULD SEE A BRIEF UPTICK IN SNOW SHOWER COVERAGE EARLY THURSDAY MORNING AS MAIN TROUGH SWINGS THROUGH. COLD AIR WILL BE IN PLACE THURSDAY...BUT WIND DIRECTION NOT OPTIMAL FOR LAKE INFLUENCED SNOW SHOWERS. WARMER AIR WILL MOVE BACK IN THURSDAY NIGHT AND FRIDAY. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... CLOUDS HAVE MANAGED TO THIN SOMEWHAT ACROSS SOUTHERN PA/NORTHERN WV AND EXPECT THIS TO PERSIST FOR A FEW HOURS. HOWEVER...SW FLOW WILL BRING A BIT MORE MOISTURE ALOFT...AS WELL AS WARM ADVECTION...WHICH WILL HELP TO SHARPEN UP THE INVERSION ALOFT. THUS...EXPECTING MOST AREAS TO SEE MVFR CIGS BECOME REESTABLISHED BY THE LATE EVENING HOURS...AND PERSIST THROUGH THE REST OF THE TAF PERIOD. CANNOT RULE OUT A FEW SNOWFLAKES TONIGHT IN LOCATIONS LIKE MGW AND LBE...BUT THIS IS NOT EXPECTED TO CREATE ANY RESTRICTIONS. ZZV COULD SEE SOME BREAKUP PAST 15Z THOUGH. WINDS WILL REMAIN CALM OR VERY LIGHT. OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/... NEXT STORM SYSTEM WILL BEGIN TO IMPACT THE REGION ON TUESDAY AND RESULT IN WIDESPREAD RAIN...CIG/VIS RESTRICTIONS...AND PERIODS OF LLWS INTO THURSDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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