Area Forecast Discussion
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216 FXUS61 KPBZ 242314 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 714 PM EDT Mon Jul 24 2017 .SYNOPSIS... A stagnant mid-level trough will keep very-humid conditions over the region today with a continued threat for showers and thunderstorms. Dry conditions are expected Tuesday through early Thursday. && .NEAR TERM /THROUGH TUESDAY/...
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Drier air is quickly filling into the region in the wake of a cold front that should be exiting the southeastern reaches of the CWA forthwith. That said, steep low level lapse rates do remain in the wake of the front, and while some clearing is occurring with its initial passage, these lapse rates are spawning stratocumulus to our north, which will likely move into the area overnight to some degree. This should preclude fog development in whatever areas it covers overnight, while areas farther southwest that are less likely to have stratocumulus will see a chance of river valley fog toward morning. Subsidence becomes the dominant player on Tuesday as high pressure moves into the region. Likewise, notable mid-level warming starts to occur, which should quickly eradicate any remnant layers of steepened lapse rates in the column and allow for ample sunshine through the day. Fries
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&& .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... Upper-level heights will rise on Tue ahead of a shortwave ridge, and broad surface high pressure will build into the Great Lakes region. The drying boundary layer and overall subsidence will support a dry, seasonable forecast for Tue/Wed. Low-level moisture will begin to increase again Wed, which will help maintain above-average minima despite light wind and increasing cloud cover. && .LONG TERM /THURSDAY THROUGH MONDAY/...
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Models are consistent for Thu in digging a deep upper-level trough along the Appalachians, which will act on an increasingly-moist and unstable airmass as a cold front crosses the region. Showers and storms along the boundary are highly probable, and PoPs were increased to reflect this expectation. The forecast for Friday into the weekend gets a bit muddy, as the evolution of the upper trough varies among the medium-range models. If the trough progresses sewd, then the weekend is shaping up to be dry and sunny, with seasonable highs. But other model solutions open the upper wave across the Appalachians, keeping the threat for clouds and precipitation (especially over the aforementioned eastern ridges) into Friday and Saturday. With an amplified upper ridge persisting in the wrn CONUS, it is likely that a mean trough will remain over the ern CONUS for the better part of the extended forecast. The net effect will be overall a seasonably-warm and -active weather pattern.
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&& .AVIATION /23Z MONDAY THROUGH SATURDAY/... At 19Z, a broken line of showers and thunderstorms was located from KDUJ-KAFJ-KPKB, with greatest coverage near MGW. MVFR ceilings will linger across the area today. The slow-moving boundary will sag south through the remainder of the afternoon. By evening, VFR conditions should persist over the area. Lingering low-level moisture may produce some restrictions in the early morning hours Tuesday. Otherwise, VFR conditions are expected through Wednesday. .OUTLOOK... VFR is expected to prevail through mid-week as high pressure builds in. Moisture will return Thu ahead of a sewd-moving trough. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.