Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
380 FXUS61 KCTP 112005 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 305 PM EST THU FEB 11 2016 .SYNOPSIS... A PERSISTENT NORTHWEST WIND WILL KEEP LAKE EFFECT AND UPSLOPE SNOW SHOWERS GOING THE REST OF THIS AFTERNOON. AN ARCTIC BLAST WILL DELIVER THE COLDEST AIR OF THE SEASON FOR VALENTINES WEEKEND. THE ARCTIC FRONTAL BOUNDARY WILL BE ACCOMPANIED BY A ROUND OF BLINDING SNOW SQUALLS LATE FRIDAY AND FRIDAY NIGHT... FOLLOWED BY DANGEROUS COLD AND VERY LOW WIND CHILLS THAT ARE EXPECTED TO IMPACT THE AREA SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... NUMEROUS...NARROW BANDS OF SNOW SHOWERS AND BRIEF SQUALLS CONTINUE TO STREAM SE AND WELL INLAND FROM THE GLAKES THIS AFTERNOON...MAKING IT ALL THE WAY INTO PORTIONS OF THE LOWER SUSQ VALLEY REGION /AND IN FACT...RIGHT TO THE MID ATLANTIC SEABOARD/. BRIEF...REDUCED VSBYS TO BETWEEN 1/4-1/2SM WILL IMPACT TRAVEL WITHIN THESE NARROW SNOW BANDS THAT COULD DROP UP TO ONE INCH OF FLUFF IN JUST A 30 MINUTE PERIOD. 18Z HRRR COMBINED WITH A LOOK AT THE LOW-MID LEVEL LAPSE RATES VIA THE NAM INDICATE THAT THE SNOW SHOWERS/BRIEF SQUALLS WILL CONTINUE UNTIL 23 THU-01Z FRIDAY BEFORE QUICKLY DISSIPATING AS THE SUBSIDENCE INVERSION DROPS FROM 7-8 KFT AGL...TO UNDER 4 KFT AGL. 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. THE WIND WILL MAKE IT FEEL MUCH COLDER LATE TDY WITH WIND CHILLS BETWEEN -10 AND +10 ACROSS THE ENTIRE AREA. THE BLUSTERY CONDITIONS WILL JUST BE A TASTE OF WHAT LOOKS LIKE IS ON THE HORIZON FOR LATER FRIDAY NIGHT RIGHT INTO SUNDAY. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... SFC HIGH PRESSURE WILL SLIDE SOUTH OF THE STATE LATE TONIGHT BRINGING GRADUAL CLEARING. FLURRIES AND SCATTERED SNOW SHOWERS WILL LIFT NORTH EARLY TONIGHT AND BE CONFINED MAINLY TO THE NORTHERN TIER BY AROUND MIDNIGHT. 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 IN A FEW OF THE PERENNIAL COLD RURAL AREAS...SUCH AS SEG AND THV - MAKING THEM 3-5F COLDER THAN THE SURROUNDING LOCALES. THE FIRST PART OF FRIDAY SHOULD BE QUIET WITH PARTLY TO MOSTLY SUNNY SKIES AND RELATIVELY LIGHT WSW WIND. CLOUDS WILL QUICKLY INCREASE FROM THE SW AS SOME MEAGER WARM ADVECTION KICKS IN AHEAD OF THE WELL- ADVERTISED ARCTIC FRONT. SOME LIGHT SNOW/SNOW SHOWERS WILL DEVELOP DURING THE AFTN...BUT ACCUMS SHOULD BE MEAGER /GENERALLY UNDER 1/2 INCH. TEMPS WILL TRY TO GET INTO THE 20S ALL OVER BUT THE PERSISTENT CLOUD COVER IN THE NW WILL LIKELY LIMIT THEM TO THE UPPER TEENS. ARCTIC FRONT AND AN EXPANSIVE AREA OF STEEP 850-700 MB LAPSE RATES GREATER THAN 8C/KM WILL PLOW ACROSS THE STATE LATE FRIDAY IN THE NW...AND AFTER DARK - FRIDAY NIGHT ELSEWHERE. THIS SHOULD BE ONE OF THOSE ONCE IN A YEAR /OR SEVERAL YEAR/ EVENTS COMPLETE WITH DANGEROUS BLINDING SNOW SQUALLS CREATING WIDESPREAD TRAFFIC/TRAVEL PROBLEMS...FROM THE COMBINED EFFECT OF HEAVY FALLING AND BLOWING SNOW - AMOUNTING TO BETWEEN 1-3 INCHES IN A SHORT 30 TO 60 MINUTE PERIOD. THUNDER WAS ALSO MENTIONED IN THE GRIDDED WEATHER FIELDS...ESP ACROSS THE NW HALF OF THE STATE BASED ON THE LATE DAY/EVENING TIMING OF THE ARCTIC FROPA. WIND CHILLS DIP TO UNDER ADVISORY CRITERIA /-15F/ EARLY SAT MORNING ACROSS THE NRN MTNS...AND DROP TO NEAR OR SEVERAL DEG F BELOW ZERO ELSEWHERE BY THEN. && .LONG TERM /SATURDAY THROUGH THURSDAY/... *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 /19Z THURSDAY THROUGH TUESDAY/... LAKE ENHANCED OROGRAPHIC SNOW WILL RESULT IN MAINLY IFR VSBYS AT KBFD/KJST THROUGH THIS AFTERNOON. THESE CONDITIONS WILL GRADUALLY IMPROVE BEGINNING THIS EVENING WHEN THE MEAN LLVL WIND 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 19Z...MAY DROP BRIEFLY TO UPPER 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 FOR THE REST OF THIS AFTERNOON AS DIURNAL HEATING/MIXING WITHIN THE RATHER DEEP BOUNDARY LAYER ALLOWS STRONGER WINDS ALOFT TO MIX TO GROUND LEVEL. ARRIVAL OF SFC RIDGE SHOULD BRING WIDESPREAD VFR CONDS AND DIMINISHING WIND TO CENTRAL PA THIS EVENING...AND CONTINUING THROUGH AT LEAST THE FIRST HALF OF FRIDAY. OUTLOOK... FRI...PM SHSN/VIS REDUCTIONS LIKELY...ESP W MTNS. PERIODS OF LIFR/VLIFR IN INTENSE SNOW SQUALLS LATE FRIDAY /NW/ AND FRIDAY NIGHT EARLY SAT MORNING CENTRAL AND SE. SAT...WINDY. SHSN/REDUCED VIS POSS W MTNS...MAINLY AM. SUN...NO SIG WX EXPECTED. MON...PM SNOW POSSIBLE. MON NIGHT AND TUE...SNOW LIKELY NW HALF OF PENN...WITH RAIN OR SNOW IN THE SE. && .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...LAMBERT LONG TERM...STEINBUGL AVIATION...LAMBERT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.