Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 210034 AFDCTP Area Forecast Discussion National Weather Service State College PA 834 PM EDT SAT AUG 20 2016 .SYNOPSIS... Warm and humid weather will continue through Sunday. A cold front will push through the region Sunday, followed by a cooler airmass with much lower humidity. The drier and cooler air will make it very comfortable for much of the upcoming week. The next significant chance for rain won`t arrive late Thursday or Friday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A few scattered thunderstorms continue across the higher terrain of the west and north. Meso models show these making the usual diurnal fade with the loss of heating, before new activity upstream begins to approach around or shortly after midnight. It will be another warm and muggy overnight as higher dewpoints upstream advect in ahead of the approaching cold front. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... a fairly sharp, but progressive nrn stream upper trough will become located across the Lower Great Lakes region by 00Z Monday. Decent height falls, instability and anomalously high (2 inch plus) PWATs will lead to favorable conditions for frequent showers and embedded (mainly sub-severe) TSRA on Sunday. SPC has maintained their MRGL risk in place for the eastern half of PA Sunday, and model consensus timing of the cfropa through the central mtns of PA (along with widespread cloud cover with only limited breaks) during the mid afternoon hours agrees with this placement and category for SVR threat. There still is sufficient llvl speed shear and veering of the vert wind profile across the SE third of the CWA Sunday afternoon to bring the threat for at least transient mesos in any strong/svr storms. Small pockets of EHI in the 1.5-2.5 m2/s2 range will be highly dependent on seeing some decent breaks in the otherwise widespread cloud cover within the region of mdtly strong uvvel associated with the RE region of a potent swrly upper jet max. Maintained basin avg rainfall of about 0.5 - 0.75 inch across the SE and a little over one inch across portions of the NW mtns. However...the high PWAT air will bring the chc for some pinpoint 2 inch amounts in places that see training TSRA. This should keep any flood threat quite minimal, but still as noted by the previous shift - a gully may get washed, but nothing more than nuisance stuff. Timing of the exit of the storms seems to be pretty solid at before noon in the NW and ~sunset in the far eastern zones. Therefore, it may get pretty nice and only a little breezy in the late afternoon across the western part of the area. The cool air and cyclonic flow in the wake of the front may generate some showers off the lakes later in the afternoon and Sun night. Temps get pretty cool Sun night with lots of 50s and l60s. This will make the requisite valley fog - but the drying before sunset will keep the fog from being too widespread and keep it mainly in the valleys and in the east where they probably won`t have a chance to dry out before it clears and cools in the evening. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... The upper level trough will be mainly through the region by tomorrow night with only lingering shower adn thunderstorms possible through the first half of the overnight period. As the trough lifts to the northeast expect that a mid level ridge and weak flow aloft will move into the region. Cooler, drier air will advect into the region bringing a period of precipitation free weather through most of next week. The next period of active weather will come as an upper level trough moves into the region Thursday night into Friday. A front with +1 to 2 anomalous PWATS progress through Friday. That should correspond with a passing but possibly weakening cold front. Dry air should be possible behind it for next weekend. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/...
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Scattered, diurnally-driven shra/tsra are dying out over the Allegheny Mtns as sun sets this evening. A brief vis reduction remains possible at KBFD and KJST through arnd 02Z. Elsewhere, VFR flying conds will persist through the late evening hours. A cold front will push east into the region late tonight and Sunday, bringing deteriorating flying conds. An increasingly moist southerly flow preceding the front will be accompanied by sct showers and cigs falling into the MVFR category across much of Central Pa btwn 07Z-11Z. The upslope flow into the northern mtns could result in IFR cigs at KBFD by arnd dawn. Further east, mclear skies and light wind could result in fog toward dawn across southeast Pa. Latest model data suggests IFR vsbys are possible at KLNS arnd dawn. Improving conds are expected over the western half of the state by Sunday aftn, as a drier westerly flow arrives behind departing cold front. Over the eastern half of the state, MVFR reductions in showers could persist well into the afternoon until passage of front. Also, a few stronger tstorms could form on the front, possibly affecting KIPT, KMDT and KLNS during the afternoon. There is high confidence of VFR conds over most of Central Pa Sunday evening, with the exception of KBFD, where a second batch of -shra could arrive with passage of upper level trough. Outlook... Mon...No sig wx expected. Tue-Wed...Patchy AM fog possible. Thu...Isold pm tsra impacts possible w mtns.
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&& .EQUIPMENT... The KCCX radar remains down for preventative maintenance, panel replacement and radome painting. The radar is expected to be running on Sunday, but may need to be taken off line again Monday to finish the work. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte/Lambert NEAR TERM...La Corte/Lambert SHORT TERM...Dangelo/Lambert LONG TERM...Dangelo/Lambert AVIATION...Fitzgerald EQUIPMENT...

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