Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 250851 AFDCTP Area Forecast Discussion National Weather Service State College PA 451 AM EDT Sat Mar 25 2017 .SYNOPSIS... A cold front will sag southward across Pennsylvania today and tonight, before returning north as a warm front late Sunday and Sunday night. Very mild conditions are expected early today and again Sunday night into Monday as we enjoy the warm sector south of the frontal boundary. However...thickening clouds and southeast flow are expected on Sunday as the boundary sags southward as a backdoor cold front...bringing cooler conditions and eventually some patchy drizzle or light rain. Unsettled conditions will last from late Sunday through Tuesday as a series of disturbances interact with the front. No heavy rain is expected during this timeframe however. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Weak surface frontal boundary is along the Pennsylvania...New York border early this morning, and will be drifting slowly to the south through this afternoon. The cold front should make it to northern Virgina and West Virginia before stalling out once again. Scattered light showers and areas of drizzle will be along and just to the north of this boundary today into this evening. The locations most likely to receive some rain today and tonight will be the northern mountains of the state. Expect less than one tenth of an inch of rain today in most places as short range/high res models indicate that there will be a shallow dry layer between the southward advancing stratus and stratocu...and the alto cu and cirrus deck. SREF`s prob for LIFR stratus ceilings behind the front will be limited to primarily the mountains to the North and Northeast of KIPT. Areas farther south stand to see the least cloud cover. Temps around sunrise today should range from the upper 30s to mid 40s in the east, to the very mild mid 50s to lower 60s across the region near and to the west of the RT 99 corridor. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Warm temps will persist this morning. However, the warmup will be short-lived, as high pressure building into New Eng pushes a backdoor cold front through central Pa during the afternoon and evening hours. A good deal of cirrus will hold temps down a bit, but even just mixing to 925mb supports max temps in the upper 60s and low 70s south of I-80. An earlier arrival of the front will result in a cooler and cloudy day across the northern tier counties, where southeast flow and nearly saturated soundings in the sfc- 850mb layer suggest patchy drizzle is possible. Further south, there could be scattered afternoon showers in the increasingly warm and unstable air over southern Pa...but most will stay dry. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Frontal boundary sags back into the region from the north (pushed by a high pressure area sliding SE across S Ontario) on Sunday as a low approaches from the Ohio Valley. This will sag cooler and more moist air into the region. Light showers/drizzle possible through much of the day, but main precip event impacts central PA Sun night into early Mon as low moves through. QPF looks to be around 0.50 inch. Temps Sunday will be noticeably cooler behind the backdoor cold front and a likelihood of rain. However, above average temperatures (especially nighttime) appear very likely through early next week, as GEFS indicates PA remains beneath a mean upper level ridge and plume of anomalous PWATs. The chance of showers again spikes with passage of next shortwave Tuesday into Wednesday and another one to start the weekend. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... Frontal boundary just north of the PA/NY border early this morning will be pushed southward through the airspace toward the PA/MD line by 25/00z as strong high pressure builds over eastern Canada. Increasing low level moisture and wind shift to the east should translate into a lower trend in flying conditions from north to south with widespread MVFR to IFR restrictions likely by later tonight into Sunday. Areas of light rain will be possible today especially near the southward-moving frontal zone with fog/drizzle overnight into early Sunday morning. The front should lift back to the north on Sunday which should allow for at least some marginal improvement especially over portions of the southern airspace. Outlook... Sun...Low risk for isolated thunderstorms in western 1/4 airspace. Mon-Tue...Sub-VFR with periods of rain. Wed...Becoming VFR. No sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir/Lambert NEAR TERM...Fitzgerald/Lambert SHORT TERM...DeVoir/Fitzgerald/Lambert LONG TERM...Lambert/RXR AVIATION...Steinbugl

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