Area Forecast Discussion
Issued by NWS State College, PA

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395 FXUS61 KCTP 281019 AFDCTP Area Forecast Discussion National Weather Service State College PA 619 AM EDT Wed Jun 28 2017 .SYNOPSIS... High pressure will move off the eastern seaboard later today setting up a warmer and more humid airflow beginning on Thursday. A cold front on Saturday will bring a brief break in the humidity. && .NEAR TERM /THROUGH TONIGHT/...
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Satellite shows patchy mainly mid clouds streaking SE across my eastern zones. Otherwise skies are clear to scattered and the GOES R Nighttime Microphysics channel shows nicely how the northern valleys have filled with fog. The fog will burn off quickly under the high summer sun leading to a bright sunny day with highs averaging in the 70s. Quite pleasant with a light wind, yet still several degrees cooler than normal. It will be the last cooler than normal day we will see for a while. The high will move overhead today and east of the area by tonight setting up a warmer and eventually more humid SW flow. The overnight will see a gradual increase in clouds from the NW with another comfortable sleeping night in store with dewpoints still only in the 50s.
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&& .SHORT TERM /THURSDAY/... By Thursday the eastern US will be under a broad upper ridge, but close to the southern edge of the main westerlies. A warmer and more humid airmass will begin to advect into the region between the offshore high and a low moving north of the Gr Lakes. Deterministic models develop a fair amount of CAPE and mid level lapse rates are forecast in the 6-7C/km range, so an afternoon shower or thunderstorm is likely in a few spots. I used the blended MOS POPs to favor the northern 1/3-1/2 of my CWA for the best chance of rain in the afternoon. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... The upper pattern starts out with the broad ridge and high heights over the eastern US, before eventually becoming more broadly cyclonic, but still with heights remaining seasonably high as most shortwave energy slides through southern Canada. Friday will be warm and humid with diurnally driven showers/storms possible. The deterministic ECMWF/GFS both show the mid levels being relatively warm suggesting coverage will be on the scattered side. A cold front is progged to be entering the region Saturday and moving east of the CWA early Sunday, so we should see a better chance of more widespread rain. The front is expected to be weak, so temperatures behind it will not change much, just a bit of a break in the humidity for the second half of the weekend. Sunday Night into early Tuesday look mainly dry as high pressure builds over the region. The cold front will begin sliding back north as a warm front Tuesday into mid week, bringing renewed humidity and increased chances for the usual summertime showers and thunderstorms. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... High pressure building into the area from the Ohio Valley will supply mainly VFR conditions and light wind tonight across central Pa. Only area of concern is BFD, and to a lesser degree IPT. Both locations received rain showers making those spots more susceptible to fog overnight. Winds have gone calm at BFD and dewpoint depressions are within 1. Given that and the clear skies I have TEMPO group for MVFR vsbys beginning at 09Z. At IPT, the rain was lighter and would put the odds of significant (IFR) reductions there at around 10 pct. Plus winds remain persistent at IPT which should further reduce chances of fog/mist formation. Elsewhere, confidence is very high in VFR conditions overnight. Any patchy fog that may form overnight should burn off by around 13Z Wednesday. High pressure over the region should ensure VFR conditions and light winds for the rest of the day. .OUTLOOK... Thu-Fri...Isolated PM tsra impacts poss, mainly northern Pa. Sat...Scattered PM tsra impacts possible. Sun...No sig wx expected. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...La Corte LONG TERM...La Corte AVIATION...Fitzgerald/Ceru

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