Area Forecast Discussion
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000 FXUS61 KPBZ 130247 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 947 PM EST Tue Dec 12 2017 .SYNOPSIS...
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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.
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&& .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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Snow showers continue but are weakening dry arctic air continues to stream in under northwesterly flow. Cloud coverage also starting to show some breaks. With that...have opted to drop the winter weather advisories from Indiana county south. Jefferson/Clarion/Forest/Venango/Mercer will keep their respective warnings/advisories with a possible narrow Huron fetch developing as low pressure continues east, flow becomes more favorable and inversion heights stay high enough overnight. Models have remained fairly consistent in hinting at this feature. Accumulations not impacted by any banding will have light additional accumulations. Very cold wind chills will persist overnight as Arctic air continues to spill southward and temps already in the single digits across northern zones.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 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 /03Z WEDNESDAY THROUGH SUNDAY/...
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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.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES...
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MD...Wind Chill Advisory until 1 PM EST Wednesday for MDZ001. OH...None. PA...Winter Weather Advisory until 1 PM EST Wednesday for PAZ007- 016. Lake Effect Snow Warning until 1 PM EST Wednesday for PAZ008- 009-015. WV...Wind Chill Advisory until 1 PM EST Wednesday for WVZ512>514.
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&& $$

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