Area Forecast Discussion
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046 FXUS61 KPBZ 241736 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1236 PM EST Tue Jan 24 2017 .SYNOPSIS... Scattered light rain and snow will diminish through the afternoon as low pressure exits toward New England. Mild Wednesday, followed by colder air and snow showers behind a Thursday cold front. && .NEAR TERM /THROUGH TONIGHT/... Upper low pulling away from the Mid-Atlantic this afternoon, with deformation zone precip continuing to shrink as it shifts southeast. Mostly cloudy skies will continue through tonight. Seasonably mild temperatures will remain through tonight. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... High pressure will briefly spell dry weather to begin Wednesday, but another system will bring a return to cooler and wetter conditions through the end of the week. Wednesday afternoon a relatively slow moving low pressure system will approach the western Great Lakes. Deepening of the mid-level low will strengthen the jet oriented parallel to the cold front feeding southern moisture along the boundary. This will fuel light rain showers as the front passes Wednesday night. Models have slowed the eastward advance of this system through the Great Lakes, and thus timing of precipitation onset has been pushed back from previous forecast. Colder air will spill into the area Thursday morning as the upper low passes to our north. With current timing, highs should occur early Thursday and temperatures will fall through the day. Strong west-northwest flow will further bolster cold air advection. A quick transition from rain to snow will likely occur Thursday morning. Conditions will then favor snow showers continuing Thursday night into Friday. By early Friday, expecting at least some snow accumulation in the favorable locations (the Ridges, and north of I- 80), but some light accumulations of an inch or less looks possible areawide. && .LONG TERM /FRIDAY THROUGH TUESDAY/... A broad area of low pressure centered over Eastern Canada will bring periodic snow chances through the weekend. With timing of individual waves difficult to pin down, will keep PoPs in line with SuperBlend numbers. The re-enforcing disturbances will drive temperatures back down to just below seasonal values through Monday. A passing ridge could temporarily quell northwest flow late Monday, but another system looks to arrive from the northwest early next week. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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IFR to low MVFR conditions are expected to persist through Wednesday morning as low level moisture behind exiting low pressure maintains a stratus layer. Ridging should return VFR conditions to the area Wednesday, though ports N of I 80 could see MVFR continue until just after the end of the TAF period. .OUTLOOK... Periodic restrictions are expected Wed night through Sun with a crossing cold front and subsequent upper troughing.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

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