Area Forecast Discussion
Issued by NWS State College, PA

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600 FXUS61 KCTP 121107 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 607 AM EST FRI FEB 12 2016 .SYNOPSIS... AN ARCTIC COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING...DELIVERING THE COLDEST AIR OF THE SEASON FOR VALENTINES WEEKEND. HIGH PRESSURE WILL SETTLE ACROSS THE STATE LATE IN THE WEEKEND...THEN A STRENGTHENING STORM WILL LIFT UP THE EAST COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A BITTER START TO THE DAY ACROSS CENTRAL PA...AS MCLEAR SKIES AND LIGHT WIND UNDER SFC RIDGE HAS ALLOWED TEMPS TO TUMBLE EARLY THIS MORNING. WIDESPREAD SINGLE DIGITS AND EVEN A -7F NOTED AT THV AS OF 10Z. MSUNNY SKIES WILL GIVE WAY TO LOWERING/THICKENING CLOUDS LATER TODAY AS WAA OVERSPREADS THE AREA IN ADVANCE OF UPPER LOW /POLAR VORTEX/ PLUNGING SOUTH FROM JAMES BAY. NEAR TERM MDLS CONTINUE TO INDICATE ISENTROPIC LIFT WILL RESULT IN SOME PATCHY LGT SNOW WILL DEVELOP DURING THE AFTN AND EARLY EVENING...PRODUCING SOME MEAGER ACCUMS OF LESS THAN AN INCH. SW FLOW AHEAD OF APPROACHING ARCTIC COLD FRONT WILL DRAW SLIGHTLY MILDER AIR INTO THE REGION BY AFTN WITH MAX TEMPS LIKELY RANGING FROM THE UTEENS OVR THE ALLEGHENY PLATEAU...TO THE M20S ACROSS THE SUSQ VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... ARCTIC FRONT WILL PLOW SE ACROSS CENTRAL PA THIS EVENING...LIKELY ACCOMPANIED BY A ROUND OF SNOW SQUALLS. STEEP LOWER TROPOSPHERIC LAPSE RTS AND STRONG FORCING AHEAD OF MID LVL SHORTWAVE SHOULD SUPPORT A BAND OF SQUALLS ENTERING THE NW MTNS ARND 00Z AND EXITING THE EASTERN COUNTIES LATE AT NIGHT. BRIEF WHITEOUT CONDS WILL LIKELY CREATE TRAFFIC/TRAVEL PROBLEMS THIS EVENING ACROSS THE NW COUNTIES AND POSSIBLY FURTHER SE LATE TONIGHT. CAN/T RULE OUT A RUMBLE OF THUNDER ACROSS THE NW MTNS BTWN 00Z-03Z SAT...WHERE MDLS INDICATE A BIT OF CAPE. ELSEWHERE...HAVE REMOVED MENTION OF THUNDER BASE ON LATEST SPC GUIDANCE AND LACK OF ANY CAPE IN MDL DATA. 00Z NCAR ENSEMBLE SUGGESTS THE HEAVIEST SQUALLS WILL FALL OVR THE N MTNS...CLOSEST PATH OF SHORTWAVE. HAVE OPTED TO FOREGO ANY ADVISORIES FOR SNOW AT THIS POINT...AS LATEST SPC SSEO AND NCAR ENSEMBLE OUTPUT INDICATE SNOW AMTS FROM FRONT AND FOLLOWING LAKE EFFECT WILL FALL SHORT OF ADVISORY CRITERIA. PLAN TO COVER THE TRAVEL HAZARD FROM EVENING SQUALLS IN THE HWO AND FOLLOW UP WITH SPS AS THE EVENT UNFOLDS THIS EVENING. ARCTIC AIR MASS WILL POUR INTO THE REGION EARLY SATURDAY...ACCOMPANIED BY GUSTY NW WINDS...WHICH WILL PRODUCE DANGEROUS WIND CHILLS ACROSS AT LEAST THE NORTHERN AND WESTERN MTNS. CURRENT WIND/TEMP GRIDS RESULTING IN MARGINAL WCHILL WARNING READINGS OF ARND -25F ACROSS THE N MTNS SAT AM THRU SUN AM. THUS...WITH SUCH BORDERLINE NUMBERS...WILL KEEP WATCH INTACT AND DEFER WARNING/ADVISORY DECISION TO THE DAY SHIFT. FURTHER SOUTH...HAVE ISSUED WCHILL ADVISORY ALONG THE ALLEGHENY PLATEAU...WHERE CONFIDENCE IS HIGH FOR WCHILLS BTWN 15F-25F. GEFS MEAN 8H TEMPS BTWN -22F AND -25F SHOULD SUPPORT HIGH TEMPS SATURDAY NO GREATER THAN ARND 0F OVR THE NW MTNS TO THE MTEENS ACROSS THE LOWER SUSQ VALLEY. DRY ARCTIC AIR MASS SHOULD PRECLUDE SIG LAKE EFFECT SNOW ACROSS CENTRAL PA SATURDAY. HOWEVER...LK HURON CONNECTION SHOULD SHOULD FOCUS THE MOST PERSISTENT SNOW SHOWERS ACROSS THE NW WARREN CO AND THE LAUREL HIGHLANDS...WHERE AN ADDITIONAL INCH OR SO SEEMS LIKELY BASED ON NCAR MESOSCALE ENSEMBLE. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... *IMPACT WEATHER HIGHLIGHTS: FRIGID TEMPERATURES AND DANGEROUS WIND CHILLS FOR VALENTINES WEEKEND. POTENTIAL WINTER STORM EARLY NEXT WEEK. POLAR VORTEX DIVING INTO NORTHERN NEW ENGLAND WILL DELIVER THE COLDEST AIR OF THE SEASON WITH ARCTIC BLAST INTO CENTRAL PA LATE SAT-SUN. THE GLOBAL MODELS AND ENSEMBLES KEEP A MEAN TROUGH IN PLACE OVER THE EASTERN US INTO THE MIDDLE OF NEXT WEEK. THE MOST NOTABLE FEATURE DURING THE PERIOD WILL BE A LOW PRESSURE SYSTEM TRACKING UP THE EAST COAST ON TUESDAY. THE LATEST 12/00Z MODEL GUIDANCE HAS TRENDED WEST WITH THE LOW TRACK...BUT THERE IS STILL A DECENT SPREAD. AT THIS TIME PRECIPITATION WITH THIS SYSTEM APPEARS LIKELY MON-TUE BUT THE TRACK WILL ULTIMATELY DETERMINE PRECIPITATION TYPE. NEXT WEEK SHOULD END ON A MILDER NOTE. THE COLDEST TEMPS/WCHILLS EXPECTED SAT NIGHT OVR THE AREA...AS 8H TEMP ANOMALIES OF NEAR 3SD BLW CLIMO GRAZE THE AREA. MINIMUM TEMPERATURES SATURDAY NIGHT INTO EARLY SUNDAY MORNING EXPECTED TO RANGE FROM ARND ZERO IN THE LOWER SUSQ VALLEY TO -10F IN THE NORTHWEST MTNS. THE FRIGID TEMPERATURES COMBINED WITH DANGEROUS WIND CHILLS /-10 TO -25 BELOW ZERO/ WILL RESULT IN AN INCREASED RISK FOR FROSTBITE AND HYPOTHERMIA. MAY NEED TO ADD COUNTIES TO THE CURRENT WIND CHILL ADVISORYF FOR SAT NIGHT. A MODERATION (WARMING TREND) IS EXPECTED INTO EARLY NEXT WEEK. THE MODEL SPREAD HAS NARROWED A BIT CONCERNING A POTENTIAL WINTER STORM SYSTEM IMPACTING THE MID ATLC/NORTHEAST NEXT MON-TUE. LATEST GEFS AND ECENS INDICATING A SFC LOW TRACK ACROSS EASTERN PA IS MOST LIKELY...WHICH WOULD FAVOR RAIN ACROSS ALL BUT PERHAPS THE W MTNS. CONFIDENCE REMAINS LOW ON PTYPES ACROSS WESTERN PA...BUT NOW DEFINITELY FAVORS RAIN ACROSS THE EAST. ALL THE MODELS ARE SIGNALING A SIGNIFICANT QPF EVENT...AND THEREFORE HAVE INCREASED POPS IN THE LKLY RANGE FOR MON NGT-TUESDAY. && .AVIATION /10Z FRIDAY THROUGH TUESDAY/... ONLY LAKE AND TOPOGRAPHIC ENHANCED SNOW SHOWERS REMAINING ARE CONFINED NEAR LAKE ERIE SHORE...BUT SCT CIG RESTRICTIONS PERSIST IN PORTIONS OF WESTERN HIGHER TERRAIN. OTHERWISE VFR CONDITIONS WILL CONTINUE FOR MAJORITY OF THE REGION BEFORE RESTRICTIONS RETURN FRI AFTERNOON. W/SW WINDS OVERNIGHT WILL BE 10 MPH OR LESS. TROUGH MOVES THROUGH THE REGION LATE FRI AFTERNOON AND EVENING WITH A BLAST OF ARCTIC AIR. THIS WILL LEAD TO DEVELOPMENT OF SNOW SHOWERS/SQUALLS...WHICH WILL BRING A RETURN OF WIDESPREAD RESTRICTIONS...ALONG WITH PERIODS OF LIFR/VLIFR IN INTENSE SNOW SQUALLS FRIDAY EVENING INTO SATURDAY MORNING. THESE WILL BE ACCOMPANIED BY GUSTY NORTHWESTERLY WINDS...AND THESE BRISK WINDS WILL CONTINUE INTO SATURDAY. OUTLOOK... 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... WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR PAZ004>006-037-041-042. WIND CHILL ADVISORY FROM 4 AM SATURDAY TO 11 AM EST SUNDAY FOR PAZ010>012-017-018-024-033. && $$ SYNOPSIS...FITZGERALD NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD LONG TERM...FITZGERALD/STEINBUGL AVIATION...RXR

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