Area Forecast Discussion
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000 FXUS61 KPBZ 271027 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 627 AM EDT Tue Sep 27 2016 .SYNOPSIS... High pressure will provide for dry conditions today. An upper low will then return the chance for showers and seasonal temperatures through the end of the week. && .NEAR TERM /THROUGH TONIGHT/... For the pre-dawn update, made only small tweaks to temperatures, dewpoints, and sky based on the latest observations. Surface high pressure will build overhead today. Some mixing will continue with expected diurnal heating, which should allow for dewpoints to further drop this afternoon as dry air aloft is brought to the surface. With southwest flow continuing on the periphery of the broad upper low over the northern Great lakes, and some slight warming aloft, temperatures should be very close to average today. Wind should diminish with the loss of heating this evening, priming the region for a good radiational cooling night. This may allow for some locations to fall into the upper 30`s or low 40`s so long as clouds associated with the upper low remain north of the region. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... The Great Lakes upper low is forecast to dig southward across the upper Ohio valley Wednesday, settling near KY/WV and cutting off from the upper level pattern through at least Friday. As models are coming into more consistent depictions, confidence in the forecast of chance/scattered shower weather with sub- average temperature is improving. Only minor changes were made to the PoP and temperature forecast based on the latest blend of guidance with likely probabilities carried over northwestern PA where a southeasterly wind will support transport of deeper Atlantic moisture inland. A period of heavier rain may be possible over this area but with little rain reported over the region in the last week, this is not significant enough to outline in the Hazardous Weather Outlook, especially with some minor east- west differences in the low position by late week. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... Most of the models lift the stubborn upper low from the middle Ohio Valley at the start of the period into the eastern Great Lakes by 12Z Sunday. Details of individual waves rotating around the low remain tricky at this distance, so kept PoPs fairly general, with a slow decreasing trend through the weekend. Expect Sunday night into the first portion of next week to be dry as a flattening ridge arrives. Near-climatological temperatures will edge back above normal by the end of the period with the departure of the upper low. SuperBlend values were slightly knocked back early in the period, but later numbers looked reasonable. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/...
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Some low clouds and fog are lingering in some of the valleys east of Pittsburgh this morning, although only DUJ is affected for now. The clouds and fog will burn off by 15Z, with VFR conditions continuing for the balance of the TAF period. Winds may gust to between 15 and 20 knots out of the southwest during the afternoon. .OUTLOOK /TUESDAY NIGHT THROUGH SATURDAY/... Upper-level low pressure will settle into the Great Lakes region through the week. Flight restrictions will be increasingly likely beginning Wednesday.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

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