Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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631 FXUS61 KPBZ 130611 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 211 AM EDT Thu Aug 13 2026 .WHAT HAS CHANGED... The risk for severe thunderstorms and flooding has decreased slightly for the Thursday night into Friday period. However, some uncertainty remains, and risks remain non-zero. && .KEY MESSAGES... 1) Scattered showers exiting by sunrise. Uncertainty continues regarding next wave of showers/storms Thursday night into Friday. Current trends keep the higher impacts to our south and west, but severe weather and flash flood impacts have a non-zero level of threat. 3) Additional rounds of showers and thunderstorms are possible into early next week, but breaks between activity are likely while severe and flooding risks currently appear limited. && .DISCUSSION... KEY MESSAGE 1... Scattered showers will continue to swing across the region through 09Z, mainly north of I-70, with no significant impact. Precipitation potential past sunrise and into this evening will be largely squashed by the presence of flat mid-level ridging and surface high pressure over our region. The next shortwave riding in the northwest flow over the southeast CONUS ridge will arrive tonight, with additional disturbances through Friday. Given the shortwaves riding over a low-level warm advection pattern with a nearly stationary effective boundary to our southwest, there are indications that training thunderstorms producing heavy rain and flash flood risks will once again be a threat somewhere in the Ohio Valley. Right now, hi-res ensemble guidance indicates that such an axis is most likely to set up to the southwest of our region. The 00Z HREF/REFS both keep the axis of highest max potential rain totals through 00Z Saturday back towards the Middle Ohio Valley and into Huntington WV. That said, there are still a couple hi- res model scenarios (in particular the NAM) that bring higher rain totals as far north as the Mason-Dixon Line, which could threaten still- vulnerable areas in eastern Ohio. While the most-likely scenario appears to keep the main flooding threat out of our area, continued vigilance is merited given the relatively poor model performance with thunderstorm complexes in this pattern. Mesoscale details, most of which will be influenced by future convective activity, will play a large role in how things play out, and as such, overall confidence in the outcome is relatively low. KEY MESSAGE 2... The synoptic pattern will undergo little change through the coming days. The predominant flow setup (ridge south to southwest of region and zonal to northwest flow overhead) stays intact potentially through mid to late next week. Periodic showers and thunderstorms, generally shorter in duration compared to this past week, remain possible in such flow while temperature largely stays near seasonal averages. Saturday is the more likely day of break from activity as Eastern Canada surface high pressure may build south, but even that scenario could change as models attempt to better time shortwave movement/timing. Longer-range machine learning guidance continues to suggest that both severe and flash flood risks remain more limited over the coming days than the previous several days. Still, it remains prudent to follow the latest forecast trends, as there are still scenarios that could bring us higher threats than currently indicated. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... A crossing shortwave is providing some light rain showers currently mainly north of PIT. These will continue to swing across the region and exit by 09Z or so, with minor impact. The main concern will be lowering ceilings in stratus. LIFR is already present at FKL/DUJ, and heights are forecast to deteriorate to MVFR and then IFR by sunrise elsewhere. Ceiling levels should increase to MVFR as mixing begins on Thursday, and eventually scatter out through the afternoon, with increasing mid/high level clouds above. VFR is then expected to continue through Thursday evening ahead of an approaching shortwave trough. Outlook... Restrictions in showers and a few thunderstorms are expected later Thursday night into Friday mainly south of a ZZV-LBE line. VFR is expected, outside of early morning fog, Friday night through Saturday as high pressure moves across the region. Restriction and shower/thunderstorm potential return Sunday into Monday with the approach and passage of a cold front. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...CL AVIATION...CL/WM