Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 270252 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1052 PM EDT THU MAR 26 2015 .SYNOPSIS... A DEEP UPPER LVL TROUGH OVER THE MISS VALL WILL SWING EAST ACROSS PENNSYLVANIA THIS WEEKEND...BRINGING COLD WEATHER. THE UPPER LEVEL FLOW BECOMES MORE ZONAL NEXT WEEK...SO TEMPERATURES SHOULD REBOUND TOWARD NORMAL. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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COLD FRONT HAS CLEARED THE REGION. HOWEVER...POST FRONTAL FGEN FORCING REMAINS IN ENTRANCE REGION OF JET STREAK...WHICH WILL SUPPORT LINGERING LIGHT PRECIP ACROSS PARTS OF THE AREA OVERNIGHT. OROGRAPHIC LIFT MAY SUPPORT A LIGHT COATING OF SNOW IN A FEW SPOTS ACROSS THE ALLEGHENY PLATEAU AS PTYPE TRANSITIONS FROM RAIN TO SNOW LATE THIS EVENING. ACROSS THE SE COUNTIES...DEEPEST MOISTURE HAS EXITED THE AREA. HOWEVER...NR TERM MDL DATA CONTINUES TO IMPLY A GOOD CHC OF ADDITIONAL RAIN SHOWERS OVERNIGHT...AS WEAK WAVE OF LOW PRES RIDES UP STALLED FRONTAL BOUNDARY JUST TO THE SE OF PA. ACROSS THE RIDGE/VALLEY REGION FROM KAOO NE THRU KIPT...DOWNSLOPING NW FLOW WILL LIKELY LIMIT ADDITIONAL PRECIP OVERNIGHT TO A FEW SPRINKLES/FLURRIES AT BEST. BLEND OF 18Z CONSALL AND LATEST LAMP SUGGEST TEMPS BY DAWN WILL RANGE FROM THE M/U20S OVR THE NW MTNS...TO ARND 40F ACROSS THE LOWER SUSQ VALLEY.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... ANY EARLY SHOWERS ACROSS THE SE COUNTIES SHOULD END BY LATE AM...AS SECONDARY SFC WAVE EXITS THE MID ATLANTIC COAST. ELSEWHERE...APPROACH OF UPPER LVL TROUGH COULD SUPPORT A FEW PM SNOW SHOWERS...MAINLY OVR THE ALLEGHENIES. STRONG COLD ADVECTION AND 850 HPA TEMPERATURES FORECAST TO FALL WELL BELOW NORMAL WILL RESULT IN AN UNSEASONABLY COLD DAY FOR LATE MARCH. MAX TEMPS SHOULD RANGE FROM ONLY ARND FREEZING OVR THE NW MTNS...TO THE M40S IN LOWER SUSQUEHANNA VALLEY. THE COLDEST AIR AT 850 HPA WITH -2 TO -2.5 STANDARD DEVIATION ANOMALIES COMES BY FRIDAY EVENING INTO SATURDAY. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... UPPER TROF DEEPENING OVER THE EASTERN U.S. AT THE START OF THE PERIOD WILL AFFECT THE WEATHER THROUGH AT LEAST THE EARLY PART OF THE WEEKEND. SIGNIFICANT PRECIPITATION ASSOCIATED WITH THIS TROF SHOULD HAVE CONCLUDED BY DAYTIME FRIDAY...BUT SEVERAL SHORTWAVES ROTATING AROUND THE UPPER TROF WILL SLOW THE ADVANCE OF THE OTHERWISE PROGRESSIVE TROF/ASSOCIATED SFC LOW...CAUSING LINGERING SHOWERS INTO SATURDAY. AREA OF HIGH PRESSURE SHOULD EVENTUALLY MOVE INTO THE REGION FOR SUNDAY INTO EARLY NEXT WEEK. BEHIND THE DEEP UPPER TROF WILL BRING ANOTHER SHOT UNSEASONABLY COLD AIR INTO THE REGION...ESPECIALLY NOTICEABLE AFTER A COUPLE DAYS OF MORE SPRING LIKE CONDS TODAY. TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL OVER THE WEEKEND. A COMPARATIVELY WEAKER NRN STREAM WAVE WILL MOVE ACROSS THE UPPER GREAT LAKES REGION AND TOWARDS THE NORTHEAST ON MONDAY. THIS WILL CONTINUE THE CHILLY TEMPS AS WELL AS BRING THE CHANCE FOR MORE SNOW SHOWERS. WEATHER WILL DRY OUT BUT REMAIN COOL FOR THE MIDDLE OF NEXT WEEK AS ANOTHER AREA OF HIGH PRESSURE ARRIVES BEHIND FRONT. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... KEY ISSUE OVER THE NEXT 24 HOURS IS THE TIMING OF THE FRONT AND THE FRONTAL RAIN AND ISOLATED THUNDERSTORMS. THERE WILL ALSO BE SOME ISSUES WITH RAIN TO SNOW IN NORTHWESTERN PA THIS EVENING. THE BEST CHANCE FOR MODEST THUNDERSTORMS IS INT THE 20Z TO 00Z TIMEFRAME MAINLY IN CENTRAL AND SOUTHEASTERN AREAS. THERE COULD BE A WEAK LINE OF SHOWERS AND THUNDERSTORMS IN SOUTHEASTERN AREAS THIS EVENING. THE RAIN....SNOW....AND LINE OF SHOWERS WILL PRODUCE AREAS OF MVFR AND IFR. BEHIND THE FRONTAL SYSTEM MOISTURE COULD PRODUCE SOME AREAS OF PATCHY FOG AND AREAS OF SNOW SHOWERS IN THE NORTHWEST...AREAS OF IFR AND MVFR. THE COLD AIR COMES IN AND COULD CHANGE THE RAIN TO SNOW OVER THE ENTIRE REGION BY FRIDAY. MAINLY VFR AND SOME AREAS MVFR IN SNOW SHOWERS IN MOUNTAINS. FRIDAY WILL BE A MOSTLY VFR AREAS MVFR IN SNSH. WINDY DAY WITH SOME GUST SPREAD ISSUES. OUTLOOK... FRI-SAT...MVFR/IFR WITH SNOW SHOWERS NORTH/WEST. VFR TO MVFR CENTRAL AND EAST WITH SCHC OF -SHRA. SUN...NO SIG WX/VFR. MON...CHANCE OF LIGHT RAIN /LIGHT SNOW EARLY/ ACROSS NW HALF WITH MVFR REDUCTIONS. VFR SE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/FITZGERALD NEAR TERM...FITZGERALD SHORT TERM...GRUMM/FITZGERALD LONG TERM...DEVOIR/GARTNER AVIATION...GRUMM

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