Area Forecast Discussion
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407 FXUS61 KPBZ 130514 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1214 AM EST Wed Dec 13 2017 .SYNOPSIS... Bitter cold through wind chills through Wednesday. A few lake- effect snow bands will bring localized accumulating snow overnight with a more widespread snow event expected to bring several inches to the region Wednesday afternoon into Wednesday night. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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Snow shower activity is still hanging on given impressive instability profile through the dendritic growth zone, however accumulation is becoming more and more tough as drier boundary layer air is working in. Bands are quickly becoming more cellular as a result, and interspersed clearing has allowed for temperatures to fall off fairly efficiently this evening. Lows were summarily lowered through morning, and given current gusting profile, wind chill headlines still look on track. The one thing to continue to watch overnight is the Lake Huron- Lake Erie dual fetch band that is meandering southward again as a mid-level vort drops to the east. This is still poised to move back into Venango/Forest/northern Clarion overnight in hi-res guidance. Some additional accumulation will be likely there, so lake effect headlines also remain in effect. Fries
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... After a brief break tomorrow morning, strong WAA aloft will quickly overspread the area during the afternoon ahead of another clipper - this one a bit further south than its predecessor with a progged surface low track along I-70. Areas along and north of the surface low should see a steady light to moderate snow beginning Wed afternoon and continuing overnight. Despite the Canadian origins of this wave, substantial large scale isentropic ascent and sufficient Pacific moisture should yield a widespread 2-4" snow event for the affected areas. Will almost certainly need a winter weather advisory headline, but after collaboration did not want to confuse the ongoing headlines with the second event, so have held off for now. Winds will once again become quite gusty across the Laurel Highlands into the WV/MD mountains late Wednesday night as classic post-frontal isobar stacking occurs west of the mountains. Could see gusts again over the 30 mph for a several hour window around 12Z Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Brief cold advection follows behind the departure of Wednesday night/Thursday`s system. This will be short-lived, however, as a general retrogression of the upper trough toward the high plains seems in store for next weekend. This will result in more normal temperatures returning to the region, but with the threat of a southern jet branch storm that should bring primarily rain across the area on Sunday. && .AVIATION /05Z WEDNESDAY THROUGH SUNDAY/... Periods of moderate snow would result in IFR conditions along a relatively narrow band impacting FKL/DUJ overnight if a Huron snow band develops...but otherwise high MVFR to VFR is expected as dry Arctic air moves in and snow development diminishes. VFR through much of the day...before the next system cross the region Wednesday night. Restrictions likely at all terminals. .Outlook... Next chance for restrictions is Friday into Saturday. restrictions in snow showers and northwest flow will continue through Wednesday. Another system will bring more snow and restrictions to many of the terminals Thursday. && .PBZ WATCHES/WARNINGS/ADVISORIES...
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MD...Wind Chill Advisory until 1 PM EST this afternoon for MDZ001. OH...None. PA...Winter Weather Advisory until 1 PM EST this afternoon for PAZ007-016. Lake Effect Snow Warning until 1 PM EST this afternoon for PAZ008-009-015. WV...Wind Chill Advisory until 1 PM EST this afternoon for WVZ512>514.
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