Area Forecast Discussion
Issued by NWS State College, PA

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287 FXUS61 KCTP 051148 AFDCTP Area Forecast Discussion National Weather Service State College PA 648 AM EST Mon Dec 5 2016 .SYNOPSIS... A storm system will move in from the Gulf Coast states and bring another period of a wintry mix of precipitation to the region Tuesday and early Tuesday Night. Much colder air will move in after a cold front passes on Wednesday. The end of the week will feature a prolonged bout of lake effect snow and much-below normal temperatures. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... 7 AM update... All is flowing along nicely. Temps have risen above freezing in all but the far NE part of the CWA where hardly anything is falling from the sky at this point. Some light precipitation does linger over the central mountains. This should continue to taper off into just a drizzle and then break up as the clouds lift and start to break up. Prev... Last of the real/substantial precip rolling through UNV right now. While this heavier precip may be SN for a brief time it is rain here in the valley and the temps are warming everywhere. A transition to a drizzly morning is in order. Patchy precip will linger through sunrise - esp in the west. Wind already turning to the west and becoming gusty in wrn PA. This may dry things up but dewpoints are still in the m30s in NErn OH. Expect a little clearing as downslope/warming starts this morning in the SE. Maxes in the m40s look OK there, and in the u30s-l40s elsewhere. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM TUESDAY/... High pressure bubble goes right overhead tonight, but it moves quickly away. Srn stream storm developing along the Gulf Coast will continue to deepen and consolidate but flow does not buckle all that much as the old upper low gets caught in the westerlies. The main sfc low should stay well to the south. But, the secondary low will move into the OH valley late Tuesday. The most difficult part of the forecast is the p-type. Many factors pulling at the forecasters this morning, including but not limited to: + Onset of precip - mainly later in the day unless one follows the outlier/faster EC. This would argue for warmer temps, esp in the C and NE zones. + Amount of warm air intrusion. Seems limited at this time, but a brief period of FZRA is almost likely at onset in the Laurels. + While much of the precip during the daylight may be snow, it will likely be falling into a warmer blyr, and will need to fall pretty heavily to accumulate. We are almost to the shortest days, so solar help is waning. The coolest locations will be in the central mtns. At this time, we will keep the 12-24 hr forecast snow amounts at or below 2" with the highest amounts over the NC mtns. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Tuesday night will be the end of the precip from the next big thing. Precip should be tailing off and will effectively stop before the cold air and front passes late Tues night and Wed morning. A brief snow squall is possible with the frontal passage. Winds will get more gusty, too. 8H temps late Wed will be -6C NW to +1C SE. This is right about normal for mid- Dec, so will paint the maxes as almost exactly climo. High pressure nosing in from the southwest for a brief time on Wed/Night will keep it generally fair. But a few SHSN may occur in the extreme northern tier due to W winds. The coldest air does not arrive until Friday. The cold adevection will kick off a LES event which will last into the weekend. 1000-500H thickness drop below 520dam - a pretty good indicator that most locations won`t get to freezing during the days Friday and Sat. Many in the N/W will not get to 25F. Wind chills will be near zero in the Laurels. Just the SE valleys could make ol Frosty to sweat briefly in the aftn. Sometime in the weekend an upper level trough (Montana Clipper?) will cross the Upper Great Lakes and may produce more-widespread snow. The POPs will be highest across the north for now as the flow is zonal/flat and little moisture will be added to the syaytem && .AVIATION /12Z MONDAY THROUGH FRIDAY/... Steadiest pcpon has moved east of the region, but lingering light showers and areas of drizzle will persist into the post dawn hours with accompanying ifr cigs. Lingering lower stratus expected in the mountains of the west and north for much of the morning, but elsewhere expect conditions to improve to VFR by mid/late morning. Outlook... Mon afternoon/evening...No sig wx expected. Tue...Mixed precip/low CIGs possible, especially late. Wed...Lingering low CIGs possible. Thu...Mixed precipitation event - low CIGs possible. Fri...Blustery and much colder with NW mtn and Laurel Highland restrictions in SHSN and areas of enhanced Lake Effect Snow. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo NEAR TERM...Dangelo SHORT TERM...Dangelo LONG TERM...Dangelo/Ceru AVIATION...Jung/Gartner

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