Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 220749 AFDCTP Area Forecast Discussion National Weather Service State College PA 349 AM EDT Wed Mar 22 2017 .SYNOPSIS... A parting shot of mid-winter cold today and tonight before a seasonably mild spring pattern returns temperatures to near or above normal levels through the end of March. A wintry mix remains possible late Thursday night into early Friday before changing to rain. The weekend should start off on a very mild with rain likely by Sunday. && .NEAR TERM /THROUGH TONIGHT/...
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Cold/dry air continues to penetrate into Central PA behind strong low level CAA via gusty NNW winds. Scattered snow showers and flurries will continue early this morning across the Northern Alleghenies with little to no accumulation expected. The main sensible wx impact felt across Central PA today will be the brisk cold especially relative to yesterday with 3/21 max temps (~50-60F) and todays minimum wind chill (~0-20F) spread on the order of 40 to 50 degrees! The cold air is being supplied by a strong 1035+mb modified arctic high pressure system that will drift across the Great Lakes this afternoon to a position virtually overhead by daybreak Thursday. The abnormally dry air coupled with clear skies and light winds will result in a very cold night with minimum temperatures falling to near-record territory. See the climate section for 3/23 minimum temperatures records.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... After a cold start, temperatures will begin to rebound as the low level flow veers to the south/southwest. Highs Thursday will be below average but it should feel warmer with very light winds and plenty of late March sunshine. WAA pattern ramps up quickly Thursday night into Friday via anomalous west-southwest low level jet. Models continue to show pcpn spreading into marginally cold/retreating and relatively dry air near the surface between 06-12z Fri. Even with some evap cooling/wet bulb effects, hard to see thermal profiles supportive of snow unless the pcpn comes in very fast. Therefore went with rain, sleet or freezing rain wx/ptypes which fits WPC guidance. Ice accumulation will be hard to come by given temps near 32F, warm surfaces and climo but will show a few hundredths for storm total ice. Overall impact appears minimal but it only takes a small amount of ice to cause problems especially during the early morning commute. Temps should climb above freezing by mid morning Friday ending the risk for ice. Rain focus should shift north into NY Friday afternoon into Friday night as baroclinic zones sets up in upper level confluence zone downstream of deep cyclone moving through the Southern Plains. The boundary placement will be key to the fcst but it looks for now that most of the area will be in the mild warm sector. && .LONG TERM /SATURDAY THROUGH TUESDAY/...
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The models and ensembles continue to show a series of upper troughs progressing onshore from the Eastern Pacific and across the Southwest/South-Central Plains before deamplifying as they move east of the MS River. The first of 3 upper troughs emerges from the Southern Plains and crosses into the MS Valley Sunday and continues to weaken as surface frontal wave translates downstream crossing the OH Valley/Great Lakes into the northern Mid Atlantic states by Monday. Blend of NBM/ECENS/WPC still indicating max POPs in the Sunday-Sunday timeframe. Above average temperatures are expected over the weekend with the warmest day likely on Saturday with some sites approaching 70F over southern PA. Sunday should also be mild but a bit cooler due to the likelihood of rain. Fcst issues pertaining to a backdoor cold front appear to be confined to New England early next week with temperatures remaining near or or above climate averages into early next week.
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&& .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... No large changes to the 03Z TAFS. Earlier discussion below. Strong cold front to the northwest, weak system over Ohio moving east, and severe storms over the south. There could be a few lower clouds and light snow showers late at BFD and JST, mainly due to dynamics, but moisture is limited. Not expecting the 3 systems to combine into anything major over central PA. Did cut back on lower clouds late, for 00Z TAF package. Wed should be mainly VFR after mid morning, as very low dewpoints work in. Gusty northwest winds. More in the way of adverse weather for Friday, into next week, as a cold front remains nearby, and split flow keeps colder air to the north, and moisture from the south nearby. Outlook... Thu...No sig wx expected. Fri...Showers/reduced CIGS possible, mainly BFD. Sat-Sun...Showers/reduced CIGS possible. && .CLIMATE... Minimum temperature records for 3/23 at select sites: MDT - 14 in 1934 IPT - 8 in 1906 BFD - 5 in 1959 AOO - 15 in 1960 && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM...Steinbugl LONG TERM...Steinbugl AVIATION...Martin CLIMATE...Steinbugl

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