Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 240546 AFDCTP Area Forecast Discussion National Weather Service State College PA 1246 AM EST Tue Jan 24 2017 .SYNOPSIS... A strengthening storm will move east of the NJ coast early Tuesday. High pressure and unseasonably mild conditions will briefly return for midweek before a pattern change brings colder temperatures and lake effect snow to close out the month. && .NEAR TERM /UNTIL 9 AM THIS MORNING/... Extended the advy for the Laurels due to new model progs of a continuation of snowfall through the night - and even into the morning as a deformation band sets up N-S right along the wrn mtns. While additional accumulations may not be more than an inch - it will be very wet and heavy stuff. This could lead to some power outages. Have aligned the end time with the other group for convenience and speed of issuance sake. May adjust the end time later - later tonight. Prev... Extremely complex potpourri of precipitation types occurring from north to south across central PA due to variations in intensity, elevation and surface temperatures. Periods of light snow and sleet continue in a ribbon from the central mountains to the Laurel Highlands. Farther north, dynamic cooling was not sufficient for a full changeover to sleet and snow...and freezing rain has been occurring over the Endless Mountain region and parts of the Middle Susq River Valley. CAMs indicate a redevelopment of TROWAL/deformation precipitation across central and north central PA...with moderate rates being maintained along and north of I80 into the Winter Storm Warning area. Most snow/sleet accums over the Laurels and Central Mountains have already taken place, but additional coatings of snow/sleet and even patchy freezing rain are likely as migratory bands propagate east to west as the Upper low tracks nwd along the mid Atlantic coast along with the sfc low overnight. All headlines remain in effect...including Laurel Highlands Advisory which expires at 05z. Will likely need to keep central Mountains advisory through the overnight due to radar trends and aforementioned CAM guidance which continues to indicate a second surge of mid/upper level energy over much central and eastern PA after midnight. Messy travel continues from the Laurel Highlands through the central mountains and parts northward overnight. && .SHORT TERM /9 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... Models continue some snow through the daytime in the NE, but also, to a lesser extent, across the rest of the area. Will consider extending the advy which is slated to expire at 12z later based on trends closer to the next update. Prev... Winter storm impacts over North-Central/Northeast PA will come to an end by Tuesday afternoon as strong surface low continues to lift northeast along the Mid Atlantic/New England Coast. Strong WAA pattern quickly follows into mid week with high pressure ridge axis crossing the area on Wednesday. Maximum temperatures on Wednesday are fcst to climb well-above normal for late January. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... A well-advertised pattern change remains on track from the second half of the week into the weekend, with high confidence in a long wave trough carving out over the Eastern U.S. This will result in a prolonged period of seasonably cold temperatures and lake effect/high-terrain snow showers during the remainder of the period. Several inches of snow is probable in the typical locations like the Lake Erie Snowbelt. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... Looks like the old upper lvl low is just northwest of the office at midnight. While the sfc and upper lvl low along the coast will become the main storm, the upper lvl low to the northwest will serve as the pivot point, and the rain and snow will work back the west for a while early today. Hint of this is the high ceiling at AOO and the west wind there. Also trends to the precipitation on the radar. More info. below. A storm moving up the Mid Atlantic coast will bring a mixture of rain and snow to central Pa overnight. Latest GLMP MELD suggests the higher terrain airfields, including BFD and JST are likely to experience predominantly IFR/LIFR conditions overnight with periods of snow, while the rest of central Pa is likely to experience occasional rain or snow with CIGs teetering between IFR and MVFR. Improvement on Tuesday, as storm lifts to the NE and precip comes to an end. Drying effect of downsloping NW flow will yield rising CIGs across eastern PA, with VFR conditions likely by evening at MDT/LNS. At the high terrain airfields of western PA, upsloping flow will likely yield lingering IFR CIGs at BFD/JST for most of the day. Bufkit soundings indicate most of central PA will experience wind gusts of 20-25kts Tuesday. Outlook... Wed...Low cigs/rain possible western 1/2. Breezy late. Thu-Fri...MVFR/IFR in snow showers west. MVFR to VFR east. Sat...MVFR/IFR in snow showers west. MVFR to VFR east. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 7 AM EST this morning for PAZ005- 010>012-017>019-024>026-033-045-046. Winter Storm Warning until 10 AM EST this morning for PAZ006- 037-041-042. && $$ SYNOPSIS...La Corte NEAR TERM...Dangelo/DeVoir/Lambert SHORT TERM...RXR LONG TERM...Steinbugl AVIATION...Fitzgerald/Martin

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