Area Forecast Discussion
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000 FXUS61 KPBZ 050126 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 826 PM EST THU FEB 4 2016 .SYNOPSIS... SEASONABLE TEMPERATURES ARE EXPECTED INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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LOW LEVEL FLOW WILL TURN MORE NORTHWESTERLY A BIT LATER THIS EVENING...INCREASING THE OVER-LAKE MOISTURE FETCH. HOWEVER...EVEN AS THIS OCCURS AND THE INVERSION HEIGHTS RISE A TOUCH DUE TO COLDER AIR ALOFT WITH THE MID-LEVEL TROUGH AXIS SWINGING THROUGH...REAL DIFFICULTY SEEMS TO BE HAD IN TERMS OF THE UNSTABLE BOUNDARY LAYER TOP COOLING ENOUGH TO GET TOWARD THE DENDRITIC GROWTH ZONE. THAT SAID...LIKELY COINCIDENT WITH THE TROUGH AXIS PASSAGE...THERE IS A BRIEF PERIOD WHERE THERE MAY BE ENOUGH INSTABILITY AND MOISTURE DEPTH TO DRIVE A FEW FLURRIES ACROSS MOST OF THE AREA. IN THE FAR NORTHERN REACHES OF THE AREA...SUCH AS NORTH OF I-80...A FEW HOURS OF NEARLY UNIDIRECTIONAL FLOW DOES MANAGE TO BISECT THE LOWER END OF THE DENDRITIC GROWTH LAYER. ADDITIONALLY...RECENT RADAR TRENDS SUGGEST THE DEVELOPMENT OF A BIT OF A MESOLOW ALONG I-80 NEAR YOUNGSTOWN. THIS WILL LOCALLY INCREASE THE DEPTH OF THE LIFTED LAYER...LIKELY INTERSECTING THE DENDRITIC LAYER A BIT EARLIER. THIS SHOULD TREND EASTWARD THROUGH THE EVENING...AND MAY WELL RESULT IN HALF AN INCH OF SNOW OR SO AS IT DOES SO ALONG THIS CORRIDOR. ALSO...IN THE RIDGES...A BIT LONGER PERIOD OF UPSLOPE NORTHWESTERLY FLOW WITH COLDER TEMPERATURES MAY ALLOW FOR UP TO A HALF OF AN INCH IN A FEW SPOTS. HOWEVER...BY DAYTIME ON FRIDAY...ALL OF THIS ACTIVITY SHOULD BE WINDING DOWN AS DRIER AIR WILL BE MOVING IN FROM THE WEST...ALLOWING FOR CRASHING INVERSION HEIGHTS AND AN INHIBITIVE BOUNDARY LAYER PROFILE. FRIES
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/... COLDER AIR WILL PULL BACK TO THE NORTH ON FRIDAY AS RIDGING BUILDS IN OVER THE UPPER OHIO VALLEY. THIS WILL ALLOW FOR A DECREASE IN CLOUD COVER AND ANOTHER DAY OF NEAR NORMAL TEMPERATURES. SATURDAY WILL BE DRY WITH INCREASED CLOUD COVER DURING THE AFTERNOON. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... A WEAK COLD FRONT WILL CLIP THE AREA SATURDAY NIGHT...BUT THE HEART OF THE COLD AIR WILL REMAIN NORTH OF THE AREA. A SHORTWAVE TROUGH WILL QUICKLY SWING THROUGH WITH THE SURFACE BOUNDARY...SO THIS MAY PROVIDE ENOUGH LIFT FOR SCATTERED SNOW SHOWERS ACROSS THE NORTH. AFTER A DRY PERIOD SUNDAY...A LARGE TROUGH ACROSS THE EASTERN UNITED STATES WILL BRING WIDESPREAD CLOUDS...SCATTERED RAIN/SNOW SHOWERS...AND EVENTUALLY COLDER TEMPERATURES. MODELS CONTINUE TO WRESTLE WITH THE DETAILS THROUGH THE PERIOD. THE LONG TERM WAS CONSTRUCTED USING THE SUPERBLEND. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... CEILINGS ARE EXPECTED TO LOWER TO MVFR CATEGORIES AS COLD ADVECTION CONTINUES TONIGHT. BUILDING HIGH PRESSURE AND THE WIND BACKING TOWARDS THE W/SW WILL HELP SCATTER OUT THE STRATOCU BY FRIDAY MORNING...IMPROVING THE MAJORITY OF TERMINALS FROM WEST TO EAST TO VFR STATUS. EXPECT KFKL AND KDUJ TO IMPROVE TO VFR CATEGORIES LATE FRIDAY AFTERNOON. .OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/... GENERAL VFR CAN BE EXPECTED THROUGH THE WEEKEND. THE NEXT CHANCE FOR WIDESPREAD RESTRICTIONS WILL BE MONDAY AND TUESDAY WITH A COLD FRONT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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