Area Forecast Discussion
Issued by NWS

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000 FXUS61 KPBZ 110814 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 314 AM EST THU FEB 11 2016 .SYNOPSIS... SNOW SHOWERS WILL GRADUALLY DIMINISH THURSDAY. TEMPERATURES WILL CONTINUE TO FALL THROUGH THE WEEK WITH BITTER COLD TO START THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/...
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AN AXIS OF LOW LEVEL DEFORMATION CONTINUES TO SLOWLY EDGE SOUTHEASTWARD INTO THE NORTHERN REACHES OF THE AREA EARLY THIS MORNING. GIVEN THAT SURFACE TEMPERATURES ARE IN THE DENDRITIC GROWTH THERMAL LAYER AND SURFACE-BASED INSTABILITY IS PRESENT...THIS AXIS OF DEFORMATION IS SUMMARILY CO-LOCATED WITH A BAND OF SNOW SQUALLS THAT HAS PLAGUED THE AREA JUST SOUTH OF I-80 TOWARD THE TURNPIKE VIRTUALLY ALL NIGHT. AS THE MORNING ENSUES...LOW LEVEL CONVERGENCE IN THIS LAYER SHOULD START TO SUBSIDE...AS FLOW TURNS MORE UNI-DIRECTIONALLY FROM THE NORTHWEST...WHICH SHOULD ALLOW FOR FAR LESS DOMINANT BANDING ALONG THIS AXIS...THUS ALLOWING FOR THE SQUALLS TO DIMINISH. HOWEVER...IN THE INTERIM...A FEW MORE INCHES OF LOCAL ACCUMULATION WILL BE POSSIBLE...ESPECIALLY ALONG HIGHWAY 422. ELSEWHERE...UNSTABLE NORTHWESTERLY FLOW WILL BEGIN TO BE OVERCOME BY DRY CANADIAN AIR ADVECTING IN FROM THE NORTHWEST. THE ONLY PLACE WHERE THIS MAY NOT ENTIRELY BE THE CASE IS IN FOREST AND VENANGO COUNTIES. HIGH RESOLUTION GUIDANCE SUGGESTS BANDING FROM LAKE HURON WILL TREND SOUTHWARD LATE THIS MORNING. THIS WOULD ALLOW FOR A MULTI-LAKE FETCH TO BRING SNOW SHOWERS FROM LAKE HURON...ACROSS LAKE ERIE...AND INTO THE FAR NORTHEASTERN REACHES OF THE CWA. THUS POPS AND THE WINTER WEATHER ADVISORY WILL LIKELY BE MAINTAINED HERE TO ASCERTAIN WHETHER THIS DEVELOPMENT DOES OCCUR. IN THE RIDGES...VISIBILITIES HAVE CONTINUED TO GENERALLY BE BETWEEN 1 AND 2 MILES THROUGH THE NIGHT. A PERIOD OF A ENHANCED SNOW SHOWER ACTIVITY WILL BE LIKELY AS FLOW TURNS TO THE NORTHWEST...HOWEVER WEAKENING SATURATION WILL MEAN LESS EFFICIENT SNOW GENERATION BY AFTERNOON. THUS A FEW MORE INCHES WILL BE POSSIBLE IN THE RIDGES...HOWEVER TRENDS BY AFTERNOON SHOULD ALLOW FOR SNOW SHOWER ACTIVITY TO TAPER OFF. ELSEWHERE...SCATTERED SNOW SHOWERS WILL BE PRESENT...HOWEVER ACCUMULATIONS SHOULD BE LIGHT/LOCAL AS DRIER AIR MOVES INTO THE AREA. IN FACT...GOING INTO THE NIGHTTIME TONIGHT...LOW LEVEL FLOW STARTS TO WEAKEN CONSIDERABLY AND TURN A BIT TO THE SOUTHWEST. THIS WILL LIKELY ERADICATE BOUNDARY LAYER RH VALUES...AND ALLOW FOR DECENT TEMPERATURE FALLS. THEY WILL LIKELY BE TEMPERED BY MORNING AS MID AND HIGH CLOUDS INCREASE...HOWEVER SINGLE DIGITS WILL LIKELY STILL BE COMMON WITH WIND CHILLS INCREMENTALLY BELOW ZERO. FRIES
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&& .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
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COLDER AIR WILL SURGE SOUTH LATER FRIDAY AS ARCTIC VORTEX DROPS SOUTH. FRONT WILL CROSS REGION LATER FRIDAY WITH A ROUND OF SNOW SHOWERS INTO FRIDAY NIGHT. BIGGER STORY WILL BE WIND CHILLS LATER FRIDAY NIGHT THROUGH SATURDAY 15 TO POSSIBLY 25 BELOW ZERO AS WINDS REMAIN UP AND TEMPERATURES WILL BE IN THE SINGLE DIGITS. HEADLINES FOR WIND CHILLS WILL LIKELY BE NECESSARY. SKIES SHOULD BEGIN TO CLEAR OUT SATURDAY NIGHT AS HIGH PRESSURE BUILDS INTO THE REGION. ALTHOUGH IT IS EARLY TO SORT OUT EFFECTS OF FRESH SNOWPACK AND JUST HOW MUCH RADIATIONAL COOLING WILL OCCUR DUE TO CLEARING SKIES...MODELS REMAIN IN GOOD AGREEMENT THAT SATURDAY NIGHT WILL BE THE COLDEST NIGHT OF THE WINTER WITH TEMPERATURES IN MANY LOCATIONS BELOW 0F.
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&& .LONG TERM /SUNDAY THROUGH WEDNESDAY/...
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SUNDAY SHOULD REMAIN DRY BEFORE THE NEXT SYSTEM MOVES IN BETWEEN SUNDAY NIGHT AND TUESDAY. MODELS ARE NOT IN AS GOOD AGREEMENT WITH THIS SYSTEM TODAY AS THEY WERE YESTERDAY...WITH SOME MODEL GUIDANCE NOW BRINGING IN THE SYSTEM FROM THE SOUTHWEST INSTEAD OF THE WEST- NORTHWEST...WHICH WOULD AFFECT BOTH COVERAGE AND TIMING OF ANY PRECIPITATION. WINDS MAY BE FAVORABLE FOR SOME LAKE EFFECT SNOW SHOWERS BEHIND THE SYSTEM...WITH A WEAK SYSTEM APPROACHING BY WEDNESDAY. WHILE SUNDAY AND SUNDAY NIGHT WILL ALSO BE COLD...TEMPERATURES SHOULD BEGIN TO APPROACH NORMAL VALUES AGAIN FOR THE WORK WEEK.
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&& .AVIATION /08Z THURSDAY THROUGH MONDAY/...
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SNOW SQUALLS WILL LIKELY REMAIN BETWEEN KBVI AND KFKL THROUGH THE MORNING BEFORE DISSIPATING. LOCAL SNOW SHOWERS WILL BE POSSIBLE AT MOST SITES...HOWEVER NO HEAVIER SNOW SHOWERS SHOULD AFFECT ANY SITE. CIGS WILL SLOWLY IMPROVE THROUGH THE DAY...WITH VFR CONDITIONS LIKELY AT MOST SITES BY TONIGHT .OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/... OCCASIONAL RESTRICTIONS ARE EXPECTED THROUGH THE PERIOD UNDER COLD UPPER-LEVEL TROUGHING. WHILE THURSDAY NIGHT AND SUNDAY SHOULD BE GENERALLY DRY...SCATTERED TO WIDESPREAD SNOW SHOWERS ARE EXPECTED FRIDAY...SATURDAY...AND MONDAY.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES...
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MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001. OH...NONE. PA...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR PAZ013- 014-016-022-023. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ007>009-015-074-076. WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ510>514.
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&& $$

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