Area Forecast Discussion
Issued by NWS State College, PA

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267 FXUS61 KCTP 210406 AFDCTP Area Forecast Discussion National Weather Service State College PA 1206 AM EDT Sun Oct 21 2018 .SYNOPSIS... Another cold front will cross the region tonight, bringing showers or rain and snow along with blustery conditions late tonight and Sunday. An accumulation of snow is expected tonight and early Sunday over the mountains. Colder than normal temperatures but mainly dry weather are expected for much of next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Evening update timed the area of heavier rain and lightning moving through the central counties. Numerous reports of graupel as the heaviest of showers passed. Tweaked PoPs to account for the organized line of showers. Heights continue to fall overnight, bottoming out late tonight as 500 mb trof axis tracks from NW to SE across the southern tier counties. This will shunt a zone of strong boundary layer winds across my extreme southern counties and bring especially ridgetop locations strong wind gusts between late tonight and sunrise Sunday. Continued the Wind Advisory for these areas with 45 mph gusts expected on ridges and perhaps even into valleys during this timeframe, as 6 hour pressure rises of 10-12 mb are expected across much of central PA. Other concern is for changeover to snow showers with areas from the Laurel Highlands to the Northwest Mountains likely to see a coating to locally 1-2" of snow as the aforementioned compact 500 mb trof and post frontal northwest flow bring a mix and changeover to snow showers west and north. Expect a few flakes to fly over the central mountains as well, but with no accumulation expected. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... By Sunday morning, The trough axis will be along the Atlantic Coast and zipping east. The cold advection will drop the 8H temps to -8C across the north on Sunday morning and going below -5C over all the area through the day. SHSN continue off the lakes and upslope areas through Sunday. A Huron connection seems to be favorable into the Laurels. The west- facing slopes could pick up as much as 3 inches. But, most of Somerset and Cambria counties should not get more than an inch. Gusty winds continue as well. Temps could touch 50F in the downslope flow to the SE of Blue Mtn, but will top out in the 30s in the N/W. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Conditions will improve Sunday night into Monday, as winds shift more to the west. Winds could go light Sunday night across the south. While the northwest would get into warm advection early on, the southeast areas could get to freezing. York and Lancaster counties still in the growing season, thus will keep the mention of a freeze in the HWO. Most of Monday into Tuesday will be dry, and turning milder. However, another system moving across the Great Lakes will pull another cold front across the region later Tue. This system will be similar to the current one. The main change was to edge temperatures up a little, and also up POPS some late Monday into Tue. Wednesday will start off similar to Sunday, but late Wed into at least Friday should be mainly dry. 00Z EC and GFS like black and white with the details late in the weekend. The 12Z runs are closer, but still too far out. The question is how energy for the westerlies phases with energy across the lower latitudes. 12Z EC shows a separate system moving off the southeast coast, before a secondary low forms with the upper lvl trough. This is beyond my new day 7. For day 7, it is mainly the superblend. Like day 6, going mainly dry on day 7. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... Several shortwaves with reinforcing cold air will traverse central Pennsylvania overnight. Winds are highly variable, ranging from nearly calm one hour, to gusting over 25 knots the next. These gusty winds are associated with the more organized clusters of showers that are moving through, and efficiently mixing stronger winds to the surface. Will see rain showers also transition to rain/snow mix overnight in the west and north. With flow becoming NNW overnight and Sunday, expect snow shower activity to be mainly spotty across the NW, with a better chance of persistent snows across the Laurels. At this point, have just included VCSH in KJST and KBFD TAFs, and will wait to see if a more organized area of SHSN develops. In any event, ceilings will remain in MVFR range, maybe dropping to IFR in snow. .Outlook... Sun...Snow showers and associated restrictions likely north and west in the morning, with improving conditions in the afternoon. VFR elsewhere. Mon-Thu...No sig wx expected. && .CTP WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 8 AM EDT this morning for PAZ033>036. && $$ SYNOPSIS...DeVoir NEAR TERM...Tyburski SHORT TERM...DeVoir LONG TERM...Martin AVIATION...Jung

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