139 FXUS61 KPBZ 110114 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 914 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/... No changes were needed for the late eve update as showers will gradually fill back in with the approach of the main frontal system. Previous... The eve update featured the adjustment of precip. probs., sky, and weather in accordance with the latest radar and high res. trends of shower-timing. The bulk of these showers will complete passage across the area this evenng in accordance with progressing shortwave support, but expect further development from the west later tonight as the cold front and parent upper trough slide eastward. Lack of instability will preclude general thunderstorm development, but cannot rule out an isolated rumble of thunder or two as the mid levels cool later tonight/predawn of Thursday. && .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 /01Z 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. && $$