FXUS61 KPBZ 230526 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 126 AM EDT Sun Aug 23 2026 .WHAT HAS CHANGED... Risk for severe weather this afternoon/evening in northwest PA is lower, with no other hazardous weather anticipated through at least mid week. && .KEY MESSAGES... 1) Spotty showers with low probability thunderstorm chances possible through this evening. 2) Minimal hazards for majority of week before widespread precipitation chances return to end the week. && .DISCUSSION... KEY MESSAGE 1... Upper troughing lingering over the upper OH River valley combined with cold advection over warm Lake Erie waters is enough to produced localized, brief showers with a low probability for thunderstorms through this evening. While SBCAPE peaks around 1000 J/kg around the I-80 corridor (enough to foster deeper convection), such lackluster shear (struggling to touch 20kts) should limit enough organization/intensification to keep storms below severe thresholds. Activity generally comes to an end after sunset as subsidence and loss of heating suppresses activity. The exception is near/north of I-80 in northwest PA where an embedded shortwaves in NW could create short periods where showers (mainly) through Monday. KEY MESSAGE 2... Lingering cool advection within northwest flow results in high temperatures around 10 degrees below the daily average Monday while high pressure supports dry weather (save for a low probability shower near Lake Erie). Height rises over the surface high ensures dry weather persists Tuesday into Wednesday while elevating temperature back to near the seasonal averages. Ensembles remain firm in an upper shortwave digging through the Ohio River Valley Thursday into Friday, creating the next round of widespread shower and thunderstorm chances. Model differences in timing of upper shortwave and surface boundary movement leaves large variability in potential storm environments (ex: spread between 25th-75th percentile SBCAPE values Thursday afternoon is around 700 J/kg, a significant value). Trough passage within the summer season means this period should be monitored, but little more can be confidently said at this time. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... Pockets of MVFR to locally IFR stratus remain possible ahead of the surface cold early this morning due to residual boundary layer moisture. A brief light rain shower can't be ruled out but overall activity is too localized to include in the TAF. Diurnal heating/mixing within the post-frontal environment likely fosters scattered to broken VFR cu (though a period of MVFR as cigs rise is possible) today. Cool NW flow may tap into warm Lake Erie waters as an aid for generating pop-up brief afternoon showers, with probabilities highest at FKL/DUJ given lake proximity. Lingering surface gradient/steep lapse rates also fosters NW afternoon winds between 15-25kts. Outlook... Outside of low probability rain showers near Lake Erie through Monday, building high pressure and height rises aloft favor VFR through the middle of next week. The next widespread restriction and rain chances returns near the end of the week. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...Frazier AVIATION...Frazier