Area Forecast Discussion
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000 FXUS61 KPBZ 251921 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 221 PM EST THU DEC 25 2014 .SYNOPSIS... BUILDING HIGH PRESSURE WILL END THE WEEK DRIER. WARM TEMPERATURES RETURN THROUGH SATURDAY. && .NEAR TERM /THROUGH FRIDAY/... SCATTERED RADAR ECHOES REMAIN EARLY THIS AFTERNOON SHOWING LIGHT RAIN/DRIZZLE POSSIBLY MIXING WITH SNOW AT TIMES. HIGHER ELEVATIONS SEE A LITTLE BETTER CHANCE OF SNOW PERSISTING THROUGH THE EARLY EVENING...BUT LITTLE OR NO ACCUMULATION IS EXPECTED. ALL PRECIPITATION IS EXPECTED TO END BY 00Z. MODEST WAA AND MIXING HAS GIVEN A RAGGED APPEARANCE TO AN OTHERWISE SOLID CLOUD DECK. BREAKS IN THE CLOUDS LEAD TO FLEETING GLIMPSES OF BLUE SKY AND SUNSHINE...BUT THE DOMINATE CLOUD DECK SHOULD LAST THROUGH LATE THIS EVENING. DESPITE THE WAA...NAM/RAP SOUNDINGS INDICATED 925MB MOISTURE REMAINING TRAPPED UNDER AN INVERSION AND HOLDING TIGHT THROUGH THE EARLY MORNING HOURS FRI. WITH THE STRONG 850MB WAA CURRENTLY PROGGED OVER OH/IN...THEY HAVE BEEN UNABLE TO CLEAR MUCH OF THEIR LLVL CLOUDS...WE MAY BE HEADED DOWN A SIMILAR PATH. THE RECENT UPDATE HAS INCLUDED HOLDING CLOUDS IN LONGER...ESPECIALLY ALONG THE NRN AND ERN PERIPHERIES. HIGH PRESSURE ALREADY KNOCKING ON OUR DOORSTEP WILL BE QUICK TO DISSIPATE THE REMAINING CLOUD COVER FRI MORNING. WITH WAA IN FULL SWING THROUGH FRI MORNING AND CLEAR SKIES EXPECTED TO LAST THROUGH THE AFTERNOON...FRI HIGH TEMPS SHOULD WARM BACK TO WELL ABOVE AVG. TAX && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... SURFACE HIGH PRESSURE RIDGE IN PLACE AT THE START OF THIS PERIOD...REMAINING IN CONTROL INTO SATURDAY AFTERNOON. W/SW FLOW WILL BRING SLOW WARM ADVECTION...WITH TEMPERATURES RISING TO WELL ABOVE NORMAL LEVELS AGAIN. MID/HI CLOUDS WILL BE SLOWLY INCREASING AS WELL IN SW UPPER LEVEL FLOW. STRONG INTERMOUNTAIN AREA H500 TROUGH FRIDAY NIGHT EJECTS ENERGY NORTHEASTWARD ACROSS THE PLAINS AND INTO THE GREAT LAKES BY SATURDAY...WITH A SURFACE LOW RACING ACROSS LAKE HURON BY 00Z SUNDAY. ALTHOUGH DECENT MOISTURE ARRIVES BY SATURDAY NIGHT...PARTICULARLY ACROSS THE SOUTHERN COUNTIES...FORCING WILL BE LACKING A BIT. WITH THE FORECAST TRACK OF THE SURFACE LOW/MIDLEVEL SHORTWAVE...EXPECT THE APPROACHING COLD FRONT TO GET STRUNG OUT AS IT APPROACHES AND CROSSES SATURDAY NIGHT/SUNDAY. DO NOT EXPECT PRECIPITATION TO ARRIVE IN EARNEST UNTIL AFTER 00Z SUNDAY...AND IT WILL REMAIN ALL LIQUID BEFORE...DURING...AND FOR A TIME AFTER FROPA. UPPED POPS TO LIKELY FOR ACTUAL PASSAGE...ROUGHLY BETWEEN 06Z AND 18Z SUNDAY. COLD ADVECTION WILL BE SLOW BEHIND THE BOUNDARY WITH FLOW NOT TURNING NW UNTIL LATE SUNDAY. A WAVE WILL FORM ALONG THE SOUTHERN END OF THE FRONT AND MOVE NORTHEASTWARD JUST EAST OF THE APPALACHIANS SUNDAY AFTERNOON. THIS WILL SLOW EASTWARD PROGRESS AND POSSIBLY LINGER PRECIPITATION IN THE SOUTHEAST CWA THROUGH SUNDAY NIGHT AND INTO MONDAY. A CHANGEOVER TO SNOW IS EXPECTED DURING THIS PERIOD AS SUBZERO H850 AIR FINALLY ARRIVES. HOWEVER...BY THAT POINT DEEP MOISTURE WILL BE GONE AND ONCE AGAIN UNFAVORABLE SNOW GROWTH CONDITIONS WILL EXIST...WHICH WILL PREVENT ANY MEANINGFUL ACCUMULATION. TEMPERATURES WILL BECOME MORE SEASONABLE BY THIS POINT. CL && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... THE MAJORITY OF THE UPCOMING WEEK WILL BE DRY WITH SEASONAL TEMPERATURES AS ZONAL FLOW SETS UP ACROSS THE EASTERN CONUS. A WAVE DROPPING SOUTH ACROSS EASTERN CANADA OVER THE SECOND HALF OF THE WEEK COULD POTENTIALLY RESULT IN A STEEPER DROP IN TEMPERATURES AND MORE PRECIPITATION THAN CURRENTLY FORECAST...HOWEVER...LATEST GUIDANCE IS IN RELATIVELY GOOD AGREEMENT THAT THIS FEATURE WILL REMAIN TOO FAR NORTH TO HAVE A MAJOR IMPACT. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... MVFR/VFR CONDITIONS PERSIST IN A RAGGED BUT EXPANSIVE CLOUD DECK. BOUNDARY LAYER MIXING AND MODEST WARM AIR ADVECTION HAS EATEN AWAY AT PORTIONS OF THE CLOUD COVER...EVEN RESULTING IN BRIEF CLEAR PATCHES...BUT OVERALL THE BORDERLINE MVFR CIGS HOLD STEADY. GOING INTO THE OVERNIGHT...MODEL SOUNDINGS INDICATE A FAIR AMOUNT OF MOISTURE HOLDING UNDER A LLVL INVERSION. WHILE ENOUGH MOISTURE MAY NOT REMAIN TO FEED A SOLID STRATUS DECK...THE TREND UPSTREAM IN OH/IN IS TO HOLD SOME LLVL CLOUDS THROUGH EARLY MORNING...ESPECIALLY FOR NRN AND ERN TERMINALS. HAVE INCLUDED MVFR CIGS FOR FKL/DUJ/LBE AND SCATTERED MVFR CIGS FOR MUCH OF THE REST. BEYOND FRI MORNING VFR CONDITIONS ARE EXPECTED UNDER SSW FLOW AROUND 8-10KTS. OUTLOOK.../THURSDAY THROUGH SUNDAY/... NEXT OPPORTUNITY FOR FLIGHT RESTRICTIONS LOOKS MOST LIKELY SATURDAY NIGHT THROUGH SUNDAY MORNING AS THE NEXT FRONTAL SYSTEM QUICKLY PASSES ACROSS THE REGION. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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