808 FXUS61 KPBZ 110321 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1121 PM EDT Wed Oct 10 2018 .SYNOPSIS... Periodic rain showers can be expected until passage of a cold front on Thursday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Made some adjustments based on hi-res model trends. Relative minimum in shower activity at present, but expect coverage to increase after midnight as the frontal boundary approaches along with the upper trough, and moisture continues to surge in from the southwest. Still expect an isolated rumble or two of thunder at most given the overall lack of instability. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/... Models are in good agreement with the cold front moving across the Allegheny Plateau and general area Thursday morning. Low level warm air advection may steepen lapse rates just enough such that a couple thunderstorms are possible, but general coverage will be low enough that I chose not to include in the gridded forecast package. With such a warm cloud layer and PWATs running >1.50" (>90th percentile), the strongest convection will be quite efficient rain producers. However, quick storm motion will limit any flood threat. Expect rain totals from near an inch in the ridges to around a half inch elsewhere. Temperatures will remain stable or even cool a bit in the afternoon as the cooler air filters into the region behind the front. A few isolated showers will remain possible along the higher elevations and along the I80 corridor Thursday evening as northwest flow fetches moisture off the lakes. Friday will be cool and cloudy with temps topping out in the 50s as a cool northwest flow continues and a stratoCu field develops off the warm lakes. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... By this weekend, upper level longwave troughing becomes more established across the eastern CONUS. A robust shortwave will move through Friday night into Saturday, bringing the next chance of rain showers. Forecast soundings show temperature profiles just a bit too warm in the low levels and too dry in the dendritic snow growth region for snow showers... but just a small change in the forecast and the atmosphere may be conducive for some flakes mixed in with rain in the higher elevations or across the northern portions of the CWA (I80 corridor). Temperatures will remain a bit below average over the weekend and through much of the new week. Another strong trough will bring another chance of rain showers Monday night into Tuesday morning. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Light rain that crossed the region is just a precursor to additional rain showers that arrive late tonight ahead of a cold front. Expect widespread MVFR conditions with pockets of IFR through Thursday morning with conditions slightly improving through the afternoon. A brief window of VFR is expected Thursday afternoon before MVFR cigs return with NW flow aloft. Outlook... Periodic restrictions will remain possible as NW flow persists...with rain and more widespread restrictions possible Fri night/Sat morning and Sun. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$