Area Forecast Discussion
Issued by NWS State College, PA

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308 FXUS61 KCTP 111706 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1206 PM EST THU FEB 11 2016 .SYNOPSIS... A PERSISTENT NORTHWEST WIND WILL KEEP LAKE EFFECT AND UPSLOPE SNOW SHOWERS GOING THROUGH THIS AFTERNOON. AN ARCTIC BLAST WILL DELIVER THE COLDEST AIR OF THE SEASON FOR VALENTINES WEEKEND...PRECEDED BY A ROUND OF BLINDING SNOW SQUALLS LATE FRIDAY AND FRIDAY NIGHT...AND FOLLOWED BY DANGEROUS COLD AND VERY LOW WIND CHILLS THAT ARE EXPECTED TO IMPACT THE AREA SATURDAY INTO SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MULTIPLE NARROW BANDS OF SNOW SQUALLS CONTINUE TO STREAM SE AND WELL INLAND FROM THE GLAKES LATE THIS MORNING...MAKING IT ALL THE WAY INTO PORTIONS OF THE LOWER SUSQ VALLEY REGION /AND IN FACT...RIGHT TO THE MID ATLANTIC SEABOARD/. BRIEF...GREATLY REDUCED VSBYS POSE A SIGNIF IMPACT TO TRAVEL WITHIN THESE NARROW BUT RATHER INTENSE SNOW BANDS THAT COULD DROP UP TO ONE INCH OF FLUFF IN JUST A 15-20 MINUTE PERIOD. LATEST...15Z HRRR COMBINED WITH A LOOK AT THE LOW-MID LEVEL LAPSE RATES VIA THE NAM INDICATE THAT THE TARGET AREA FOR ONE OR TWO EXTENSIVE/INTENSE SQUALL BANDS SHOULD SHIFT TO THE NE HALF OF THE CWA THIS AFTERNOON AS MEAN BLYR WINDS BACK JUST 5-10 DEGREES. THESE SNOW BANDS WILL CONTINUE TO HAVE A GOOD DUAL LAKE CONNECTION FLOWING OVER THE LONG AXIS OF LAKE HURON. WILL FORECAST MAINLY A COATING TO ONE INCH ALONG AND NORTH OF A LINE FROM KUNV TO KSEG...HOWEVER SOME LOCATIONS IN THE CENTRAL MTNS AND WEST BRANCH/MIDDLE SUSQ VALLEY COULD SEE ANOTHER QUICK 2-3 INCHES OF FLUFFY/WIND BLOWN SNOW BETWEEN 14Z AND 23Z. SOME LOCATIONS MAY NEED TO BE PLACED IN A SHORT FUSED WINT WEATHER ADVIS DEPENDING ON EXACTLY WHERE THIS MESOSCALE FEATURE SETS UP. WILL BE MONITORING RADAR TRENDS AND HIGH RES MESO MODELS CLOSELY THIS AFTERNOON. WILL MAINTAIN CURRENT WINTER WEATHER ADVISORIES OVER THE LAURELS AND WRN MTNS...AND LES WARNINGS AND ADVISORIES FOR THE FAR NW SNOWBELT WHERE PERSISTENT UPSLOPE AND LES SNOWS ARE EXPECTED TO CONTINUE INTO THIS EVENING BEFORE THE MEAN LLVL FLOW BACKS MORE TO THE WEST AND THE SUBSIDENCE INVERSION BEGINS TO DROP QUICKLY FROM 7-8 KFT AGL...TO UNDER 4 KFT AGL. THE WIND WILL MAKE IT FEEL MUCH COLDER TODAY WITH WIND CHILLS BETWEEN -10 AND +10 ACROSS THE ENTIRE AREA ALL DAY LONG. THE BLUSTERY CONDITIONS WILL JUST BE A TASTE OF WHAT LOOKS LIKE IS ON THE HORIZON FOR SATURDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... THE SNOW SHOWERS DO BEGIN TO TAPER OFF IN THE LATE AFTN AND EVENING. THE ACCUMS SHOULD BECOME NEGLIGABLE NOT TOO LONG AFTER SUNSET. THE END TIMING OF THE ADVYS/WARNING WILL BE KEPT AS IS AT 03Z. HOWEVER...MANY PLACES S OF ELK CO WILL SEE JUST A FLURRY OR TWO IN THE EVENING. TEMPS DROP INTO THE SINGLE DIGITS TONIGHT AS SOME CLEARING TAKES PLACE IN THE NW...BUT THE CALM AIR IN THE SE COULD CAUSE THE TEMPS THERE TO BECOME COLDER. SNOW PACK AND CALM AIR DO WONDERS TO MAKE IT COLDER THAN WE THINK IT WILL BE. WILL PAINT IN A DIP AROUND THE TYPICAL FRIDGES OF SEG AND THV - MAKING THEM 3-5F COLDER THAN THE SURROUNDING LOCALES. THE FIRST PART OF FRIDAY SHOULD BE QUIET SAVE A QUICK INCREASE IN CLOUDS FROM THE SW AS SOME MEAGER WARM ADVECTION KICKS IN AHEAD OF THE WELL-ADVERTISED ARCTIC FRONT. SOME LIGHT SNOW WILL PROBABLY BREAK OUT/SLIDE IN DURING THE AFTN. TEMPS WILL TRY TO GET INTO THE 20S ALL OVER BUT THE PERSISTENT CLOUD COVER IN THE NW WILL LIKELY KEEP THEM U20. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... *IMPACT WEATHER HIGHLIGHTS: SNOW SQUALLS LIKELY WITH ARCTIC FRONT FRIDAY NIGHT-SATURDAY. FRIGID TEMPERATURES AND DANGEROUS WIND CHILLS FOR VALENTINES WEEKEND. POLAR VORTEX DIVES FROM HUDSON BAY SOUTHEAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND THURSDAY-SUNDAY. THE GLOBAL MODELS AND ENSEMBLE MEANS KEEP A `MILDER` TROUGH PATTERN IN PLACE OVER THE EASTERN US INTO NEXT WEEK. EMERGENCE OF SOUTHERN STREAM SHORTWAVE AND ITS INTERACTION WITH THE NORTHERN STREAM FLOW CREATES THE POTENTIAL FOR WINTER PRECIPITATION MON-WED BUT WITH A HIGH DEGREE OF UNCERTAINTY/LOW CONFIDENCE. A PATTERN SHIFT TO PACIFIC ZONAL-TO SOUTHWEST FLOW ALOFT WITH RISING/ABOVE NORMAL HEIGHTS IS FCST BY THE END OF NEXT WEEK. THIS FAVORS A RETURN TO MILDER WEATHER. LAKE EFFECT AND UPSLOPE SNOW SHOWERS CONTINUE INTO THE WEEKEND BEFORE TAPERING OFF ON SUNDAY...AS ARCTIC HIGH BUILDS OVER THE REGION. ADDITIONAL LIGHT SNOW ACCUMULATIONS ARE LIKELY IN THE FAVORED NORTHWEST SNOWBELT AND HIGHER TERRAIN ALONG THE ALLEGHENIES/LAUREL HIGHLANDS. THE COLDEST AIRMASS OF THE 2015-16 WINTER SEASON REMAINS POISED TO ARRIVE THIS WEEKEND...AS A BLAST OF ARCTIC AIR DELIVERS A SHORT DURATION COLD OUTBREAK TO CENTRAL PENNSYLVANIA. SNOW SQUALLS ARE LIKELY WITH THE ARCTIC FRONTAL PASSAGE FRIDAY NIGHT INTO SATURDAY. MAX/MIN TEMPERATURE DEPARTURES OF -20 TO -25 DEGREES BELOW CLIMO ARE FCST SATURDAY AND SUNDAY. MINIMUM TEMPERATURES SATURDAY NIGHT INTO EARLY SUNDAY MORNING RANGE FROM 0F IN THE LOWER SUSQ. VALLEY TO -10F IN THE NORTHWEST ALLEGHENIES. THE FRIGID TEMPERATURES COMBINED WITH DANGEROUS WIND CHILLS /-10 TO -25 BELOW ZERO/ WILL RESULT IN AN INCREASED RISK FOR FROSTBITE AND HYPOTHERMIA. WIND CHILL HEADLINES ARE A GOOD BET AND PRECAUTIONS SHOULD BE MADE NOW TO PROTECT/PREPARE FOR THE UPCOMING COLD SNAP. A MODERATION (WARMING TREND) IS EXPECTED INTO EARLY NEXT WEEK. THERE IS STILL A LOT OF SPREAD CONCERNING A POTENTIAL STORM SYSTEM IMPACTING THE NORTHEAST EARLY NEXT WEEK. THE OPERATIONAL EC REMAINS MORE BULLISH THAN THE GFS IN DEVELOPING A SIGNIFICANT CYCLONE AND HAS TRENDED EVEN FURTHER TO THE WEST WITH IS 10/12Z RUN. CONFIDENCE REMAINS LOW BUT THE SYSTEM WILL NEED TO BE MONITORED. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... LAKE ENHANCED OROGRAPHIC SNOW WILL RESULT IN MAINLY IFR VSBYS AT KBFD/KJST THROUGH THIS AFTERNOON. THESE OCNDITIONS WILL GRADUALLY IMPROVE BEGINNING THIS EVENING WHEN THE MEAN LLVL WINDS BACKS FROM THE NW...TO A MORE WESTERLY DIRECTION AS HIGH PRESSURE SLIDES BY JUST TO OUR SOUTH ACROSS THE MIDDLE OHIO RIVER VALLEY. THROUGHOUT THE CENTRAL RIDGE AND VALLEY REGION AND OVER THE SUSQ VALLEY AIRFIELDS...MAINLY VFR AT 17Z...WILL LIKELY DROP TO FREQUENT MVFR CIGS AND VSBYS...WITH EVEN SOME VERY BRIEF IFR IN THE HEAVIER SNOW SHOWERS AND SQUALLS. A TIGHT PRES GRADIENT WILL BRING GUSTY WINDS UP TO 25KTS THIS AFTERNOON AS DIURNAL HEATING/MIXING WITHIN DEEPENING BOUNDARY ALLOWS WINDS ALOFT TO MIX TO GROUND LEVEL. ARRIVAL OF SFC RIDGE SHOULD BRING WIDESPREAD VFR CONDS AND DIMINISHING WIND TO CENTRAL PA THIS EVENING. OUTLOOK... FRI...PM SHSN/VIS REDUCTIONS LIKELY...ESP W MTNS. SAT...WINDY. SHSN/REDUCED VIS POSS W MTNS...MAINLY AM. SUN...NO SIG WX EXPECTED. MON...PM SNOW POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR PAZ005. LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR PAZ004. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR PAZ010-017-024-033. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...DANGELO/LAMBERT LONG TERM...STEINBUGL AVIATION...ROSS/LAMBERT

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