Area Forecast Discussion
Issued by NWS

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000 FXUS61 KPBZ 241746 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 1246 PM EST WED DEC 24 2014 .SYNOPSIS... STRONG LOW PRESSURE AND ITS ASSOCIATED COLD FRONT WILL CROSS THE REGION TODAY INTO TONIGHT BRINGING SHOWERS AND STRONG WINDS. && .NEAR TERM /THROUGH TONIGHT/... NO CHANGES MADE THIS MORNING AS THE NEAR TERM LOOKS TO BE IN GOOD SHAPE. **NOTE** THERE WAS AN ERROR OVERNIGHT THAT RESULTED IN HIGH SNOW AMOUNTS MAKING IT INTO THE FORECAST FOR TOMORROW MORNING. WE ARE CURRENTLY WORKING ON THE ISSUE...BUT IN THE MEANTIME PLEASE DISMISS HIGHER AMOUNTS. PREV DISCUSSION BELOW.. DEEPENING LOW PRES AND ITS ASSOCIATED CDFNT WL TRACK FM THE OH VLY INTO THE GT LKS RGN TDA INTO TNGT. PERIODIC SHWRS WL CONT TDA INTO TNGT AS MSTR STREAMS IN FM THE GULF IN SW FLOW AHD OF THE ADVNG SYSTEM...AND AS FROPA OCCURS. AS COLD ADVCTN SETS UP A FEW SNW SHWRS ARE PSBL OVRNGT. PROGRESSION AND A LACK OF SUSTAINED CNVRGNC SHOULD LMT BASIN AVG RAIN TOTALS TO ARND A HALF INCH FOR THE PD. THE POTENTIAL FOR STRONG WINDS WITH PASSAGE OF...AND IMMEDIATELY BEHIND THE CDFNT IS EXPD WED EVE INTO ERLY THU. IN ADDN...ELEVATED INSTBY COULD RESULT IN A FEW TSTMS ALG THE CDFNT LT TDA AND THIS EVE...SOME OF WHICH COULD MIX DOWN DAMAGING WNDS. THESE DAMAGING WND GUSTS COULD BE HANDLED BY CNVCTV WRNGS IF THIS POTENTIAL MATERIALIZES. UNTIL THEN...STRONG WARM ADVCTN WL CAP THE SFC TDA...INHIBITING MIXING/GUSTS. ISSUED A WND ADVY FOR GUSTS 45 TO 50 MPH ASSOCIATED WITH THE SYNOPTIC PRES GRADIENT WNDS LT TDA INTO ERLY THU. THE ADVY MAY BE AUGMENTED BY STORM PREDICTION CENTER PARTICIPATION IN A SHALLOW CONVECTIVE EVENT AS MNTND ABV. TEMPS ARE EXPD TO AVG ARND 20 TO 25 DEG ABV SEASONAL LVLS TDA. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... CONTD GUSTY WNDS ARE EXPD INTO ERLY THU ESP ESP ACRS WRN PA AND IN THE RIDGES. WKNG PRES GRADIENT SHOULD ALLOW FOR DCRG WND GUSTS THRU THE DAY. SNW SHWR CHCS ARE EXPD THU MRNG INTO ERLY AFTN WITH AN ADVNG UPR TROF...THOUGH LACK OF DEEP MSTR AND MARGINAL TEMPS SHOULD ALLOW FOR LTL IF ANY ACCUMS MAINLY N OF I 80 AND IN THE RIDGES. BLDG HIGH PRES IS PROGGED TO BRING DRY WEA LTR THU INTO FRI NGT. ANOTHER ADVNG GT LKS SHRTWV WL RTN RAIN SHWR CHCS SAT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... SOUTHWESTERLY FLOW ALOFT WILL REMAIN IN PLACE THROUGH THE EXTENDED AS SEVERAL SHORTWAVES DIVE SOUTH ACROSS THE INTERMOUNTAIN WEST AND REINFORCE LONGWAVE TROUGHING. MODELS CONTINUE TO SHOW POOR CONSENSUS IN HANDLING DETAILS...MAINLY WITH PLACEMENT RATHER THAN TIME. A MORE BROADBRUSH WAS CONTINUED GIVE NT HIGH UNCERTAINTY BUT IN GENERAL..FRONTAL SYSTEMS ARE PROGGED TO IMPACT THE REGION OVER THE WEEKEND AND AGAIN LATE MONDAY / TUESDAY. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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WITH THE FORECAST AREA STILL MOSTLY IN THE WARM SECTOR...VFR CONDITIONS TO START FOR MOST TERMINALS. WITH THE EASTERN RIDGES ON THE FRINGE OF CONTINUED DAMMING...LOWER CLOUDS AND EVEN SOME FOG LINGER THERE. LLWS GROUPS INCLUDED AS SSW WINDS OF 40-50 LIE JUST A COUPLE THOUSAND FEET OFF THE SURFACE. WELL-ADVERTISED COLD FRONT WILL PUSH THROUGH DURING THE EVENING HOURS BETWEEN 22Z AND 04Z. BAND OF LOW-TOPPED CONVECTION STILL BEING FORECAST BY HRRR AND OTHER MODELS AND HAVE HANDLED THIS WITH TWO HOUR TEMPO GROUPS IN EACH TAF. CIGS WILL DROP BACK TO MVFR AS THE FRONT APPROACHES AND PASSES. MAIN ISSUE WILL BE THE WIND...WITH S/SW GUSTS TO 40-45 KNOTS POSSIBLE WITH CONVECTION..AND IMMEDIATELY FOLLOWING FROPA. WINDS WILL SLOWLY DIMINISH WITH TIME OVERNIGHT BUT STILL EXPECT AT LEAST 20-30 KNOT GUSTS THROUGH THE REMAINDER OF THE TAF PERIOD. MVFR CIGS WILL CONTINUE...PERHAPS LOWERING TO IFR BY 12Z CLOSER TO LAKE ERIE. LINGERING PRECIP WILL CHANGE OVER TO SNOW SHOWERS BY 12Z AREAWIDE...BUT SIGNIFICANT RESTRICTIONS FROM SNOW ARE NOT FORECAST. OUTLOOK.../WEDNESDAY NIGHT THROUGH MONDAY/... CIG/VIS RESTRICTIONS THROUGH THURSDAY WILL IMPROVE TO VFR FRIDAY AND CONTINUE UNTIL ANOTHER FRONTAL SYSTEM CROSSES THE REGION SATURDAY AFTERNOON.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES...
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MD...WIND ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR MDZ001. DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MDZ001. OH...WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST THURSDAY FOR OHZ039>041-048>050-057>059-068-069. PA...WIND ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR PAZ007>009-013>016-020>023-029-031-073>076. WV...WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST THURSDAY FOR WVZ001>004-012. WIND ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR WVZ021>023-041. DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR WVZ023- 041.
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