Area Forecast Discussion
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411 FXUS61 KPBZ 221920 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 320 PM EDT SUN MAY 22 2016 .SYNOPSIS... Showers today will give way to drier and warmer weather through mid week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... A semi-stationary mid-level low continue to reside just to our east and is throwing moisture back toward the eastern fringe of the CWA still at this hour. However, contrary to the preponderance of guidance, it hasn`t made very much westward progress during the day. Instead, a second mid-level low that dropped southward and brought colder air at 500 mb with it has managed to steepen the lapse rates over Ohio and far western Pennsylvania enough to allow for showers to develop in these areas which saw some breaks in the clouds. The convective showers that have developed from this will likely wind down a bit after sunset, while the activity associated with the mid-level low to our east will likely linger along the eastern edge of the CWA much longer into the night. With all of that said, skies will start out mostly cloudy this evening, but as convective activity fades, some scattering out of clouds will be likely across the western two-thirds of the CWA. Farther east, breaks in the clouds will be far less numerous. Areas that do clear out may well see some fog development overnight, as well. This will be due to the fact that dewpoints remain within a few degrees of 50F. In addition, weak low level advection will likely keep drier air from filtering into the CWA overnight. Fries && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Upper trough will gradually lift to the east, through late Tuesday, being replaced by building high pressure. Residual moisture and support from a shortwave rotating along the western edge of the trough will bring the regeneration of showers and some thunderstorms Monday afternoon, much like today. Generally confined this to counties east of I-79. With more sunshine anticipated west of I-79, near season temperatures were forecast. By Monday night, high pressure will be building overhead, giving way to mostly clear skies and warming temperatures, under southwesterly flow through, early Wednesday. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... Western CONUS troughing/Eastern CONUS ridging is forecast to develop with general west-southwest flow over the Upper Ohio for the latter half of the week. Warm, moist advection will support increasing, shortwave-dependent precip chances as the weekend approaches. With uncertainty in timing of individual shortwaves embedded within the flow, have stayed close to climo POPs, which is similar to a blend of model guidance. With building heights and warm advection, anticipate above average temperatures through the start of next weekend. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... IFR conditions will generally erode this morning with the slowest improvements at KLBE and KMGW, where light NW upslope flow will allow for stratus to linger the longest. As a mid-level low drops southward and increases instability as the mid-levels cool, this should allow for better cumulus development again this afternoon. Scattered showers will develop across the area, and a few thunderstorms will be possible. Coverage of thunder will not be sufficient to include in the coded forecasts at this time. Fries .OUTLOOK /SUNDAY NIGHT THROUGH THURSDAY/... Restrictions are possible through Monday before the upper low exits. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

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