FXUS61 KPBZ 191938 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 338 PM EDT Tue Aug 19 2025 .SYNOPSIS... High pressure will maintain dry weather today. Scattered shower and thunderstorm chances will return tonight and Wednesday with a weak cold front. After seasonable temperatures Wednesday, highs will gradually warm into the weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... KEY MESSAGES: - Dry weather today with increasing clouds this evening. - Uncertainty with rain chances over night. --------------------------------------------------------------- Warm and dry conditions today with mostly sunny skies will push high temperatures this afternoon back into the upper 80s; lower 80s across the I-80 corridor and higher terrain. Clouds will likely increase this evening with an approaching disturbance from the west. Probabilities increase between 9pm and 11pm for isolated showers/thunderstorms in eastern Ohio/near Lake Erie. There is uncertainty with how much rain will reach the ground since elevated dry air may evaporate precipitation. Currently, it is looking like the northern counties are most likely to receive at least 0.05 inches of rain or more. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... KEY MESSAGES: - Scattered shower/storm chances return tonight and Wednesday. - A few higher terrain showers possible Thursday afternoon. ---------------------------------------------------------------- Scattered rain chances will increase overnight ahead of the trailing cold front, dissipating in the wake of the front by Wednesday afternoon/evening. Upslope showers across the ridges may linger through the afternoon. All indications are that precipitation will be widely scattered, with some locations receiving very little rainfall. Probability for total rainfall of >0.25" remains at 60% or lower, with highest values in Mercer, Venango, and Forest counties. Still, modeled PWATs for Wednesday morning are anomalously high and range from 1.8 to 2.0". Though unlikely, if deeper convection is able to develop, localized flash flooding can't be ruled out. Renewed high pressure across the Great Lakes and Ohio Valley should keep most of the area dry overnight into Thursday. Some weak troughing could help to initiate stray diurnal showers primarily over the ridges Thursday afternoon. With Hurricane Erin to our east, flow will be out of the northeast on Thursday. && .LONG TERM /FRIDAY THROUGH TUESDAY/... KEY MESSAGES: - Above average temperatures expected into the weekend - Precipitation chances return Saturday into Sunday with a passing cold front - Cooler weather begins next week. ------------------------------------------------------------------- Extended forecasts indicate that a ridge of high pressure over the Ohio River Valley will be present into Friday, bringing mostly dry conditions and temperatures that are near to above average. A passing cold front and an upper-level trough will likely increase the chances of precipitation Saturday into Sunday, but rainfall amounts look low this far out. NBM PQPF for >0.25" range from just 30%-40% for counties along the Appalachian ridge-line and less than 25% chance west of Pittsburgh. Of note, machine learning does indicate a 5% to 15% chance of severe weather with this passing front on Sunday, so this will need to be monitored in the coming days. Generally high confidence exists in persistent eastern CONUS troughing by early next week. This should keep temperatures below average during the first half of next week. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... Confidence remains high that VFR conditions are expected this afternoon and evening for a number of terminals ahead of a passing cold front. Diurnal drivencu is likely east of PIT through early afternoon with upsloping under southeast flow within the boundary layer. After 00Z, an approaching cold front is expected to bring isolated showers and lower cigs with increasing low-level moisture within the boundary layer. MVFR to IFR conditions are expected between 06Z to 13Z Wednesday. Then, diurnal mixing is expected to lift cigs to MVFR/VFR between 16Z to 19Z Wednesday. Light shower activity may linger east of AGC with gradual upsloping Wednesday afternoon/evening; MGW/LBE may be impacted. Outlook... Thursday, remnant low-level moisture may create MVFR/IFR conditions during the early morning hours. VFR conditions are expected Thurs afternoon with building high pressure. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...Rackley NEAR TERM...Lupo SHORT TERM...Rackley/Lupo LONG TERM...Rackley/Lupo AVIATION...Hefferan