Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 030333 AFDCTP Area Forecast Discussion National Weather Service State College PA 1033 PM EST Fri Dec 2 2016 .SYNOPSIS... A large and deep storm system will move slowly across northern New England through Saturday, keeping a prolonged period of cool northwest flow and a gusty wind over the local area. A ridge of high pressure will slide east across the commonwealth for Saturday night and Sunday accompanied by fair dry weather and light wind. A weak frontal boundary will then cross the region Sunday night and Monday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Cold cyclonic flow over the Great Lakes will keep a blanket of strato-cu clouds over practically all of the CWA overnight. Chances for lake enhanced snow will increase as the low level flow becomes more favorable to steer the snow showers into the northern mountains. The HRRR shows this support for increased banding by midnight, and even hints that narrow bands of snow showers could reach into central areas. The JST ASOS reported UP for a time so there could be some patchy freezing drizzle. A light accum of a coating to one inch should occur across the Laurel Highlands overnight, while the NW mtns (specifically Warren and Mckean counties see snowfall totals of 1-2 inches with locally higher amounts possible north and west of the city of Warren. Additional light snowfall Saturday morning from LES showers could bring 18-24 hour totals to 3 or 4 inches throughout the typical snowbelt of NW Warren County (and perhaps portions of Mckean County). However, these amounts will be just under LES Advisory Criteria of 3 inches/12 hours. Min temps early Saturday will vary from the upper 20s across the higher terrain of nrn and wrn PA, to the l-m 30s elsewhere.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... The stacked low pressure over moves over the Canadian Maritimes. The mean WNW boundary layer flow off the Great Lakes will be persistent with multiple narrow bands of mainly lake effect snow expected to spread a little more inland (developing south across the Laurel Highlands) and last into Sat Night. Clouds will be pesky and linger across much of the CWA right through the day Saturday. Max temps Saturday will be slightly colder across the north and west, but slightly warmer than today (Friday) across the Susquehanna River Valley. Still, these numbers are within a few degs of normal for the first part of Dec. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Late Sat night and Sunday brings a brief respite as high pressure builds east across the state. Sunday evening and night, a period of light snow is looking likely as a northern stream shortwave races through the region with a burst of warm advection. QPF looks to be on the order of a tenth of an inch or less, but occurring overnight many places could see their first coating of snow of the young season by Mon morning. Snow is more likely in the NW than SE. Another ridge moves through on Monday as progressive weather pattern becomes more active. On Tues there is decent agreement in bringing the SW US upper low up through the Ohio Valley as a shearing out shortwave and diffuse surface low. Unless cold air damming traps enough chilly air in the low levels to make for some freezing rain, the precip type with this midwest system looks to be mainly rain. The end of the week brings some model disagreement with the GFS/GEFS being faster than the ECMWF with the next large upper trof and frontal system. Either way, precip looks like a good bet around the Thu/fri period as all solutions eventually bring this trough through. So predictability is increasing, but timing issues remain. Best bet for precip at this point is mainly rain over the SE as decent push of warm air lifts ahead of the system, with a rain/snow mix further north where warm air will not infiltrate as much. Behind the trough, looks like a chilly weekend in store with a potential sharp dropoff in temps. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... Satellite continues to show a pretty solid deck of clouds covering all of Central Pennsylvania. Ceilings ranging from low MVFR in the west and north, to VFR in the east. Additionally, radar shows an area of light snow and rain moving across norther tier of Central Pennsylvania this evening. This precipitation is falling as occasional light snow in KBFD, to occasional light rain in KIPT. This area of precipitation corresponds well to shortwave depicted on models. Persistent WNW flow will keep threat of lake precipitation into the mountains overnight into Saturday. After passage of shortwave, flow settles down, which may add somewhat to organization of lake snow bands. HRRR and RAP has the idea of somewhat organized lake snows developing into the NW after 03z...then continuing into Saturday as well. Overall, MVFR to occasional IFR in snow in KBFD, with same thing possible at KJST. Will wait and see the evolution of exactly where banding sets up, and adjust TAFs as appropriate. Downsloping flow east of the mountains should result in better conditions further east. Mainly VFR expected at KUNV/KIPT/KMDT/KLNS through the TAF window. Temporary dips to MVFR cigs overnight at KAOO. The entire region will continue to see breezy conditions last through the next 24 hours. Outlook... Sat...SHSN with ocnl IFR vsbys at KBFD/KJST, mainly in the morning. VFR elsewhere. Sun...Light snow/reduced vis possible at night, mainly NW Mtns. Mon...No sig wx expected. Tue...Mixed precip/low CIGs possible across the nrn mtns, with a mdtly heavy 0.50-1.00 rainfall expected across much of Central and Southern PA. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...Lambert LONG TERM...Gartner/RXR AVIATION...Jung/Lambert is the U.S. government's official web portal to all federal, state and local government web resources and services.