Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 010924 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 424 AM EST SUN FEB 1 2015 .SYNOPSIS... LOW PRESSURE WILL CROSS THE CENTRAL MISSISSIPPI RIVER VALLEY TODAY AND MOVE INTO THE OHIO VALLEY TONIGHT...AND CROSS THE STATE ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION ACROSS THE AREA THIS AFTERNOON INTO MONDAY. A PERIOD OF FREEZING RAIN IS LIKELY ACROSS THE SOUTH AND CENTRAL SECTIONS TONIGHT. ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY AFTERNOON INTO TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LIGHT PRECIPITATION DEVELOPING WELL OUT AHEAD OF SFC LOW OVER EASTERN KANSAS THIS MORNING...ALONG A COLD FRONTAL BOUNDARY DROPPING SOUTHWARD ACROSS THE EASTERN GREAT LAKES AND OHIO VALLEY. THE AFOREMENTIONED LOW PRESSURE CENTER WILL TRACK ALONG THIS BOUNDARY THIS AFTERNOON AND TONIGHT...AND ACROSS THE SOUTHERN TIER OF PENNSYLVANIA BY MONDAY MORNING. ALL HEADLINES RETAINED FOR THIS FORECAST CYCLE. MAIN CONCERNS ARE THAT POPS WERE TOO HIGH TO BEGIN THE STORM THIS AFTERNOON...WHERE ONLY VERY LIGHT AMOUNTS OF QPF AND SNOW ARE EXPECTED. IN FACT...HI RES HRRR AND HRW-ARW SHOW A FRACTURED MOTHEATEN PRECIP SHIELD AT BEST REACHING ACROSS THE ALLEGHENIES LATE THIS MORNING AND AFTERNOON AND LARGELY DISSIPATING DURING THE MID TO LATE AFTERNOON HOURS. THINK THERE WILL BE A SIZABLE LULL IN PRECIPITATION FOR MANY AREAS THIS AFTERNOON BEFORE THE MAIN EVENT APPROACHES THIS EVENING AND LATER TONIGHT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... LOW PRESSURE MOVES UP THE OHIO RIVER TONIGHT. BY MONDAY MORNING IT SHOULD BE OVER KPIT...AND ROLL OVER THE SOUTHERN HALF OF THE LOCAL AREA. MAIN QPF FALLS IN THE 03Z TO 09Z TIMEFRAME FOR MANY... AND THIS SIX HOUR PERIOD WILL BE CRITICAL FOR SNOW ACCUMS OVER THE CENTRAL MOUNTAINS...JUST NORTH OF THE CHANGEOVER ZONE. FASTER/ GREATER MIXING WILL DECREASE SNOW AMOUNTS SUBSTANTIALLY. FOR NOW HAVE NUDGED THE MIXING ZONE NORTH AND DECREASED SNOW AMOUNTS SOUTH OF INTERSTATE 80 INTO THE 4-6" RANGE. AS A RESULT...GREATER FZRA POTENTIAL EXISTS WITH THIS SOLUTION THAN PREVIOUS THINKING. WHILE THE FARTHER NORTH/WARMER SOLUTION WILL CUT DOWN THE SNOW AMOUNTS IN THE CENTRAL ZONES...WARNING CRITERIA SNOWFALL IS EXPECTED NORTH OF INTERSTATE 80. ADVY AND SUB ADVISORY SNOW AMOUTNS ARE EXPECTED ACROSS THE SOUTHERN THIRD OF CENTRAL PA... BUT THE CHANCE FOR ICING IS ENOUGH TO WARRANT AT LEAST AN ADVY FOR THEM. SFC LOW RAPIDLY TRACKS EAST OF THE AREA BY MIDDAY MONDAY...WITH COLDER AIR POURING BACK INTO THE COMMONWEALTH ON THE BACKSIDE OF THE LOW. EXPECT LITTLE IF ANY ADDITIONAL SNOW ACCUMULATION BY MON AFTERNOON ACROSS THE NORTH. PRECIP WILL HAVE SHUT OFF ACROSS CENTRAL AND SOUTHERN AREAS BY MIDDAY. SHARPLY COLDER AIR IS POISED TO OVERSPREAD CENTRAL PA AGAIN ON MONDAY NIGHT. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE. HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A RETURN OF BELOW ZERO WIND CHILLS. TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS TIME IT LOOKS TO BE ON THE WEAKER SIDE. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... THE RIDGE CONTINUES TO WEAKEN AS THE SHALLOW ARTIC AIR HAS MAINLY DISSIPATED AS ITS MOVED EASTWARD. THIS HAS DELAYED THE ONSET OF MVFR CIGS /AND ANY GRADUALLY DETERIORATING VSBYS TO IFR. THE ONSET OF CONDITIONS HAS BEEN PUSHED BACK. THE LOWERING CONDITIONS WILL OCCUR FROM WEST TO EAST BETWEEN 11-18Z AS DEEPENING MOISTURE /AND THE ONSET OF LIGHT SNOW/ STREAKS EASTWARD ALONG AND AHEAD OF A SLOWLY SWD SAGGING COLD FRONT. WIDESPREAD IFR TO LIFR CONDITIONS ARE IN STORE FOR LATE SUNDAY INTO EARLY MON AS HEAVIER SNOW IMPACTS THE NORTHERN HALF OF THE STATE. THE SOUTHERN HALF WILL SEE A WINTRY MIX WORK INTO THE SOUTHERN TAF SITES...FROM JST AND AOO...TO KMDT- KLNS AREA WITH POTENTIAL FOR ICING. THIS IS DUE TO WARM AIR ADVECTION INTO THE MID LEVELS...AND COLD TEMPERATURES AT THE SURFACE. LLWS POSS SUNDAY NIGHT ACROSS THE S/SE AS LOW LEVEL JET ROTATES THROUGH. OUTLOOK... SUN...WIDESPREAD IFR-MVFR CIGS AND IFR VSBYS DEVELOPING DURING THE MORNING-EARLY AFTERNOON HOURS. LLWS POSS SUN NIGHT SE. MON...REDUCED CONDS EARLY...GRADUALLY IMPROVING AS THE STORM MOVES AWAY FROM THE AREA. LLWS POSS MON AFT/NIGHT. TUE...NO SIG WX. WED...MVFR IN SHSN NW...VFR SE. THU...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM 9 AM THIS MORNING TO 1 PM EST MONDAY FOR PAZ004>006-010>012-017>019-037-041-042-045-046-049>053-058. WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 8 AM EST MONDAY FOR PAZ033>036-064>066. WINTER STORM WARNING FROM 9 AM THIS MORNING TO 8 AM EST MONDAY FOR PAZ024>028-056-057-059-063. && $$ SYNOPSIS...DEVOIR NEAR TERM...DEVOIR SHORT TERM...DEVOIR LONG TERM...RXR AVIATION...LAMBERT/CERU

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