Area Forecast Discussion
Issued by NWS State College, PA

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310 FXUS61 KCTP 111200 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 700 AM EST THU FEB 11 2016 .SYNOPSIS... A PERSISTENT NORTHWEST WIND WILL KEEP LAKE EFFECT AND UPSLOPE SNOW SHOWERS GOING ALL DAY. AN ARCTIC BLAST WILL DELIVER THE COLDEST AIR OF THE SEASON FOR VALENTINES WEEKEND WITH DANGEROUS COLD AND WIND CHILLS EXPECTED TO IMPACT THE AREA SATURDAY INTO SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 630 AM UPDATE... MULTIPLE BANDS NOW OFF THE LAKE AND THE WESTERN LAKE STUFF IS FLOWING INTO PBZ AND UP INTO THE LAURELS. FORECAST SNOW TOTALS SHOULD BE OK DESPITE THE LOW QPFS FROM MDLS...AS IT IS SO COLD/DRY AND THE SNOW IS SO FLUFFY. LONG-BAND STILL IN THE MESO PROGS FOR THIS AFTN...SO HAVE INCREASED CONFIDENCE IN THAT OCCURRANCE. THE DESCENT OFF THE ALLEGHENIES CAN DRY THINGS UP...THOUGH. PREV... INTENSE BAND OF SNOW JUST LIFTED OUT OF THE BACKYARD. THIS BAND PERSISTED DEEP INTO THE SERN COS WITH ACCUMULATIONS INTO LEBANON CO. A SLIGHT SOUTHWEST FLOW IS SHOVING THE BAND TO THE EAST. THE BAND IS BREAKING UP BUT THE WIND IS GOING BACK TO A NWRLY DIR OVER THE WRN MTNS ATTM. THE CONVERGENCE LINE IS NOW A GOOD SQUALL UNTO ITSELF - PRESSING STEADILY SOUTH AND EAST AND WILL IMPACT I-80 SHORTLY. THIS SQUALL IS MOVING ALONG PERPENDICULAR TO IT/S ORIENTATION. BUT A QUICK HALF INCH TO INCH OF SNOW IS POSSIBLE. THE BANDS IMMEDIATELY OFF THE LAKE ARE REACHING INTO WARREN AND MCKEAN COS...BUT THE MEAN FLOW IS STILL A LITTLE TOO WRLY TO PUSH THEM TOO MUCH FARTHER S. THE WINDS CONTINUE TO VEER THRU THE MORNING. THIS SHOULD ALLOW MORE BUT SHORTER BANDS TO OCCUR. HOWEVER...A GOOD HURON CONNECTION IS PROGGED BY THE MESO GUIDANCE TO FOCUS A LONG BAND THRU KERI AND KFIG AND RIGHT THRU UNV THIS AFTN. HAVE NUDGED POPS UP IN ANTICIPATION OF THIS FEATURE. NRN CENTRE CO MAY NEED AN ADVY WITH SNOW OVER THE NEXT 18HRS RIGHT AROUND 3 INCHES. BUT THE BAND MAY BE 40 MILES EITHER DIRECTION AND THE UNCERTAINTY LEADS ME TO HOLD OFF FOR NOW. SOME OF THE MOST INTENSE SNOW THERE WILL BE OVER IN JUST AN HR OR TWO. 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 /12Z THURSDAY THROUGH MONDAY/... LAKE ENHANCED OROGRAPHIC SNOW WILL RESULT IN PREDOMINANTLY IFR VSBYS AT KBFD/KJST THIS MORNING. DRYING/DOWNSLOPING FLOW WILL RESULT IN PROGRESSIVELY MORE FAVORABLE CONDS EAST OF THE MTNS...WITH OCNL MVFR CIGS/FLURRIES POSSIBLE AT KAOO/KUNV AND A HIGH CONFIDENCE OF PREDOMINATELY VFR CONDS AT KIPT/KMDT/KLNS. SFC RIDGE BUILDING IN FROM THE OHIO VALLEY SHOULD CAUSE LAKE EFFECT SNOW SHOWERS TO DWINDLE BY THIS AFTN...WITH PREDOMINANTLY MVFR CONDS RETURNING TO KBFD/KJST AND VFR ELSEWHERE. A TIGHT PRES GRADIENT OVR THE REGION IS ALREADY PRODUCING GUSTS IN EXCESS OF 20KTS ACROSS PARTS OF CENTRAL PA AT 12Z...AND MDL SOUNDINGS INDICATE GUSTS TO ARND 25KTS WILL BECOME WIDESPREAD BY LATE AM...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...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...STEINBUGL AVIATION...FITZGERALD

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