Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 030643 AFDCTP Area Forecast Discussion National Weather Service State College PA 143 AM EST Sat Dec 3 2016 .SYNOPSIS...
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Northwest flow will continue today and early tonight. A ridge of high pressure will slide east across the commonwealth tonight and Sunday accompanied by fair dry weather and light wind. A weak frontal boundary will then cross the region Sunday night and Monday and make light precipitation, and perhaps a coating of snow in the northern mountains. A storm with mainly rain may affect the area during mid-week, some mixed precipitation may occur at the beginning of that storm.
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&& .NEAR TERM /UNTIL 7 AM THIS MORNING/...
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1 am update... Precip still very light. Temps still marginal or just too warm for any accums. Prev... 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 /7 AM THIS MORNING THROUGH 6 PM SUNDAY/... 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 /SUNDAY 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 /07Z SATURDAY THROUGH WEDNESDAY/... At 06Z satellite showing an extensive stratocu deck across most of Pa associated with an low pressure over Southern Quebec. CIGs ranging from low MVFR at KBFD/KJST to between 4-5kft at the lower elevation airfields, including KIPT/KMDT/KMDT. The main aviation concern this morning will be at KBFD/KJST, where moist WNW flow forced to ascend the Appalachians will create borderline IFR CIGs and occasional snow showers. Downsloping flow will result in progressively better conditions further east, with MVFR cigs likely at KUNV/KAOO and VFR conditions at KIPT/KMDT/KLNS. High pressure approaching from the west will cause snow showers to diminish across the Western Mtns later today. However, model soundings still indicate persistent MVFR CIGs at KBFD/KJST through this evening. WNW winds should continue to gust to around 20kts today, then expect diminishing winds this evening as high pressure builds in. Outlook... Sun...Light snow/reduced vis possible at night, mainly NW Mtns. Mon...No sig wx expected. Tue...Mixed precip/low CIGs possible, especially late. Wed...Lingering low CIGs possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...Dangelo/La Corte SHORT TERM...Lambert LONG TERM...Gartner/RXR AVIATION...Fitzgerald

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