Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
183 FXUS61 KPBZ 142318 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 718 PM EDT Mon Sep 14 2026 .WHAT HAS CHANGED... No significant changes were made to the latest forecast. Updated for the 00z TAF issuance. && .KEY MESSAGES... 1) Dry through Tuesday night 2) Warmer and more humid with shower and thunderstorm chances returning Wednesday and Thursday 3) Active pattern this weekend into early next week && .DISCUSSION... KEY MESSAGE 1... High pressure will maintain dry weather through Tuesday night as it tracks east across the region. Some patchy river valley fog is possible tonight as temperatures drop into the mid 40s to around 50. As the high shifts east Tuesday, wind will veer to the south as 500mb heights rise. This should result in high temperatures around 10 degrees warmer than today. KEY MESSAGE 2... Ridging is expected to begin to shift southward on Wednesday, as a cold front approaches from the Midwest and Great Lakes region. The front should stall Wednesday as the flow aloft become parallel. Isolated to scattered showers and thunderstorms should increase during the afternoon north of I-70 as this front approaches and stalls, though ridging to the south should maintain generally dry weather. The ridge should continue to drift southward Thursday, as a shortwave trough tracks east across the Upper Ohio Valley region. Backing flow aloft with the crossing wave should push the cold front across the region, with higher chances for showers and thunderstorms. Shear (20kt) and instability (ML CAPE 750 j/kg or less) are expected to remain marginal for Thursday, limiting any severe weather potential. This is support by the latest ML guidance, which shows minimal potential for severe storms. Precipitable water does increase to around 1.8 inches, though the progression of the front could also limit the locally heavy rainfall potential. The front should exit the area on Friday, with diminishing shower chances. KEY MESSAGE 3... Model ensembles indicate a more zonal flow across much of the region this weekend into early next week, though large differences in individual models exist. In general, disturbances embedded in the flow should maintain daily shower and possible thunderstorm chances through this period, with above average temperatures. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Diurnal cu have mostly dissipated with the loss of heating and passing mid to high level clouds are expected overnight. Probabilities for steam fog near dawn along the river valleys remain with models having low chances but a distinct river valley footprint to probabilities associated with visibility drops tomorrow morning. Given the low chances, no mentions have been included in the TAF. VFR continues tomorrow with a VFR fair weather cu field and S or SSE winds sustained near 10 kts. Outlook... Outside of morning valley fog, VFR is expected through Tuesday. Precipitation chances with lower probability restrictions return Wednesday through Friday morning coincident with gradual breaking down of upper ridge with shortwave trough/surface cold front passage. Shower and thunderstorm chances increase from N-S late Wednesday into late Thursday with the approach and passage of a cold front. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...WM AVIATION...Frazier/AK