Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 210641 AFDCTP Area Forecast Discussion National Weather Service State College PA 241 AM EDT Tue Mar 21 2017 .SYNOPSIS... Scattered rain showers early this morning will give way to seasonably mild conditions for the first full day of Spring. Cold air will plunge back into the area Tuesday night through Wednesday before retreating during the second half of the week. A period of snow or ice is possible ahead of the returning warm air later in the week. A milder pattern will persist through the weekend with opportunities for rain into early next week. && .NEAR TERM /THROUGH TONIGHT/... High res guidance shows current pcpn activity with leading frontal boundary weakening as it drifts east across the southern 1/2 of the area through daybreak. Temperatures over the higher terrain along and to the north of I-80 could support rain/snow mix with no accumulation expected. Rain ends early and is followed by a mainly dry and seasonably mild day with highs in the 45-55F degree range. Secondary/arctic cold front pushing southeast across the Lower Great Lakes this evening will traverse the area overnight into early Wednesday morning. Noticeably colder air will follow with temperatures falling into the teens and 20s by 22/12z. Gusty winds will add to the chill with apparent temps in the single digits and teens. Some snow showers/flurries are also possible as strong CAA spills downwind of the lakes but short northerly fetch and dry air should limit any accumulation to a brief coating over Northern Alleghenies. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Brisk and cold conditions on Wednesday could be the coldest air we see until fall. High temps will be -15 to -25 degrees below average for late March, but record low maxes do not appear to be in jeopardy. Lingering snow showers or flurries in the morning should taper off by the afternoon. 1040mb high pressure builds over the area Wed night, setting up a pretty cold night for this time of year. Favorable radiational cooling and dewpoints in the single digits and teens should be a good proxy for minimum temps with single digit lows over the northern tier. Would not rule out a few of the usual cold spots dropping into negative territory. WAA pattern quickly follows what could be winter`s last gasp with moderating temperatures into the second half of the week. Models indicate risk for snow/ice mix ahead of the warm air as pcpn spreads into retreating shallow cold layer near the surface Thursday night-AM Friday. Max POPs are over the NW 1/3 of the area based on a multi-model consensus blend. && .LONG TERM /FRIDAY THROUGH MONDAY/... The Warm front will likely lift into New York State and the warm sector should expand NE cover the entire CWA Friday afternoon through most of Saturday with temps surging well into the 40s to around 50F Friday, then into the lower 50s (north) to lower 60s (south) on Saturday. Timing and location of the deep cold air and associated 1040+ sfc high over southeastern Canada will play a key role in the storm track of a southern stream wave that will be sheared east from the Mid Miss Valley late Saturday...through the Ohio River Valley...Central Appalachians and Mid Atl Coast Sunday through Monday. Pops for rain/showers will increase Saturday night through Sunday night, but capped them off in the likely range at this point. Shallow cold air could backdoor us from the NE later in the weekend per the continued/consistent trend of the 12Z EC and GEFS. This could lead to some precip type issues across northern PA at a minimum. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/...
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Low pressure will track south of Pa early today, spreading scattered rain showers and falling CIGS across the region. Latest HRRR and 20/21Z SREF probability charts suggest IFR conditions are possible between 10Z-14Z at JST/BFD, MVFR conditions are likely at UNV/AOO and perhaps no sig reductions at the lower elevations airfields of eastern Pa, including IPT/MDT/LNS. Any showers should push east of the region around 12Z, as the low pressure system passes off the Mid Atlantic Coast. However, residual low level moisture ascending the Allegheny Mountains could create lingering MVFR stratocu at BFD/JST into early THIS afternoon. The arrival of high pressure and drier air should result in widespread VFR conditions by late in the day, even at BFD/JST. Outlook... Wed-Thu...No sig wx expected. Fri-Sat...Showers/reduced CIGS possible, mainly BFD.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM...Steinbugl LONG TERM...Lambert/Steinbugl AVIATION...Fitzgerald/Lambert is the U.S. government's official web portal to all federal, state and local government web resources and services.