Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 291826 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 126 PM EST THU JAN 29 2015 .SYNOPSIS... AN ALBERTA CLIPPER/ARCTIC COLD FRONT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE WILL RETURN FOR LATE FRIDAY INTO SATURDAY. A NEW STORM IS EXPECTED TO PASS WELL SOUTH OF THE AREA LATER SUNDAY INTO MONDAY...FOLLOWED BY ANOTHER SURGE OF COLD AIR FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... HAVE DECIDED TO COVER THE THREAT FOR ICY CONDITIONS INTO THE EVENING HOURS WITH A WEATHER ADVISORY OVER MY SOUTHERN TIER. OVERALL REASONING HAS NOT CHANGED WITH JUST ENOUGH WARM AIR ALOFT EXPECTED TO CAUSE A PERIOD OF NUISANCE-TYPE ICING. THE MAIN AREA OF PRECIP IS ON TRACK AND SHOWN BY THE HRRR TO BE ENTERING MY WESTERN ZONES BY 18-19Z. STILL SOME CONCERN FOR A BRIEF PERIOD OF LIGHT FREEZING RAIN OR SLEET SO WE PUT AN ADVISORY OVER THE SOUTHERN COUNTIES TO COVER THE POTENTIAL FOR SOME LIGHT ICING. GUIDANCE IS CONSISTENT IN SHOWING WARM AIR SURGING IN ALOFT TODAY...THEN BEING PINCHED OFF QUICKLY AS PRECIP DEVELOPS AND THE COLUMN EVAPORATIVELY COOLS. HOWEVER...THE RAP/HRRR HOURLY DATA SHOW THE WARM AIR ACTUALLY PUSHING BACK NORTH BETWEEN 21-00Z OVER THE SWRN ZONES...COMPLICATING THE PRECIP TYPE SCENARIO FROM THE LAURELS EASTWARD ALONG THE MARYLAND BORDER COUNTIES. A STRONG SHOT OF WAA ALOFT AND MODERATELY STG UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF AN UPPER LVL JET MAX ACROSS SRN ONTARIO WILL LEAD TO PERIODS OF SNOW THIS AFTERNOON INTO TONIGHT. ALREADY 4-STAR SNOW AT MEADVILLE WITH MODERATE SNOW OVER NERN OHIO UP INTO ERIE. SNOWFALL TOTALS IN OUR GRIDDED FORECASTS LOOK REASONABLE AND WE HAVE INCLUDED LIGHT ICE TOTALS OF A TENTH OF AN INCH OR LESS. THE COLD FRONT WILL BE ENTERING WESTERN PA JUST AFTER DARK...AND SHOULD BE SWINGING THROUGH MY EASTERN ZONES BETWEEN MIDNIGHT AND 6 AM. SNOW WILL TAPER TO SNOW SHOWERS AND FLURRIES BY LATE TONIGHT...MAINLY IN THE ISOLATED FORM ACROSS THE CENTRAL AND SOUTHERN VALLEYS. LOW TEMPS TONIGHT WILL RANGE FROM THE MID TO UPPER TEENS ACROSS THE WRN MTNS...TO THE MID AND UPPER 20S ACROSS THE SUSQ VALLEY. IF THE FRONT IS FASTER THAN EXPECTED...THESE COULD BE A TAD TOO HIGH. && .SHORT TERM /FRIDAY/... FRIDAY WILL BE A BLUSTERY AND COLD DAY AS ARCTIC AIR PAYS A RETURN VISIT. LINGERING SNOW SHOWERS WILL FAVOR THE USUAL WESTERN AND NORTHERN HIGHER TERRAIN WITH CENTRAL AND EASTERN AREAS PROBABLY SEEING LITTLE MORE THAN SOME STRAY FLURRIES. TEMPS WILL LIKELY PEAK EARLY AND EITHER STAY STEADY OR FALL THROUGHOUT THE DAY. WIND CHILLS WILL RANGE FROM 5 TO 15 BELOW ZERO OVER WESTERN HIGHER ELEVATIONS BY LATE IN THE DAY AS WINDS BECOME GUSTY BEHIND THE DEPARTING FRONT. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... PERIODS OF GENERALLY LIGHTER SNOW WILL LINGER INTO EARLY FRIDAY...AS THE MAIN COLD FRONT DROPS SE. A TIGHT LLVL PRESSURE GRADIENT IN THE WAKE OF THE COLD FRONT WILL BRING GUSTY NORTHWEST WINDS AND SLOWLY FALLING TEMPS ACROSS THE REGION DURING THE DAYLIGHT HOURS FRIDAY. WIND GUSTS WILL BE IN THE MID TO UPPER 20 KT RANGE FOR MOST AREAS CREATING A WIND CHILL IN THE SINGLE DIGITS TO LOW TEENS IN THE SUSQ VALLEY....AND 5 BELOW TO 15 BELOW ACROSS THE NRN AND WRN MTNS. FRIDAY NIGHT WILL BE BITTERLY COLD...AS SKIES CLEAR AND WINDS DIE DOWN. LOW TEMPS WILL VARY FROM THE SINGLE DIGITS BELOW ZERO ACROSS THE NORTH...TO SINGLE DIGITS ABOVE ZERO IN THE SOUTH. A BRIGHT DAY ON SAT...BUT NOT REAL WARM. STILL HAVE CHC POPS ON SUNDAY. A LOT OF SPREAD IN THE MODEL OUTPUT THE LAST FEW DAYS. 12Z MODELS BACKING OFF SOME NOW. PATTERN SUPPORTS LOW PRESSURE SYSTEMS THAT ARE FAST MOVING AND WEAK. WOULD STILL EXPECT SOME LIGHT SNOW INTO MONDAY MORNING. A COLD NIGHT MONDAY NIGHT...AS THE NEXT HIGH BUILDS INTO THE AREA. SOME HINTS AT ANOTHER FAST MOVING LOW FOR MID WEEK...FOR NOW WENT WITH CHC POPS. MINOR CHANGES TO THE PACKAGE MADE. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... VFR CONDITIONS WILL RAPIDLY DETERIORATE AS SNOW OVERSPREADS THE REGION FROM WEST TO EAST. SNOW WILL BEGIN SHORTLY IN BRADFORD. EXPECT IFR CONDITIONS TO DEVELOP RAPIDLY WITH THE SNOW...SPREADING EAST 18-00Z. SOUTHERN TIER TERMINALS FROM JST-AOO EAST INTO THE LOWER SUSQ VALLEY COULD SEE A PERIOD OF LIGHT FREEZING RAIN OR SLEET AS THE PRECIPITATION DEVELOPS. REDUCED CONDITIONS SHOULD IMPROVE OVERNIGHT WITH THE PASSAGE OF THE COLD FRONT...AROUND 03Z FRIDAY OVER THE WEST. MORE LIKE 06-09Z OVER THE SERN AREAS. THE CONDITIONS AT BFD AND JST WILL LIKELY REMAIN MVFR/IFR WITH SNOW SHOWERS INTO FRIDAY. OUTLOOK... SAT...VFR. SUN...LOWER CONDITIONS POSSIBLE OVER SOUTHERN AREAS ASSOCIATED WITH A STORM MOVING THROUGH THE CAROLINAS. MON...REDUCED CONDS EARLY IN SNOW SHOWERS. IMPROVING FROM WEST TO EAST AFTERNOON ONWARD. TUE...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR PAZ004>006- 010-011-017-024-033. WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR PAZ025>028- 034>036-056-057-059-063>066. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LAMBERT/MARTIN AVIATION...LA CORTE

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