FXUS61 KPBZ 202218 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 618 PM EDT Fri Mar 20 2026 .WHAT HAS CHANGED... Severe storm potential has trended down a bit for this evening with the daytime rain and clouds hindering destabilization. Given strong heating and favorable dynamics Sunday, a small uptick in strong storm potential is noted, and SPC has expanded the Slight Risk into southwestern Pennsylvania. && .KEY MESSAGES... 1) Low potential for strong to severe storms Friday evening, with hail appearing to be the primary threat. 2) Somewhat better storm potential on Sunday, with all severe threats in play. && .DISCUSSION... KEY MESSAGE 1... An area of stratiform rain and thick cloud coverage with lift under the favorable upper jet exit region has continued to plague the area into early this evening. The back edge of the rain will move north to south across the area likely clearing by 8pm or so. Quickly on the heels of that rain is a cold front following a similar path. Destabilization through the day was greatly inhibited by the aforementioned factors, but that said, the post-frontal environment could support a low-end risk for hail with any storms after 8pm or so. Steepening mid-level lapse rates with colder air filtering in behind the front, approaching the 7-8 C/km range, may support some elevated instability (latest CAMs suggesting MUCAPE values of around 500-800 J/kg). Combined with 0-6 km shear still between 40 and 50 knots, any successful convection could have sufficient updraft/downdraft separation for marginally severe hail in the strongest cells. The big question is *if* storms occur as a post-frontal environment typically isn't where you'd expect development. By this point, soundings are generally in good agreement that the surface is stable, or at worst isothermal, so a damaging wind and tornado threat appears to be on the very low side. QPF totals through tonight top out in the 0.25 to 0.50 inch range, with the higher totals likely in the ridges as supported by hi-res model data. Of course, locally higher totals could be possible in any heavier storms. Any showers/storms should largely pull south of the region by 06Z with the departing boundary. KEY MESSAGE 2... After a quiet Saturday, a somewhat more robust threat for severe weather is present for Sunday. Warm frontal passage Saturday night, attached to Great Lakes low pressure, allows for southwest flow promoting strong heating during the Sunday daylight hours. Well-above normal high temperatures are forecast, supported by 850mb temperatures approaching 15C. Highs will mainly be in the 70s, perhaps near 80 in the vicinity of the Mason-Dixon Line. MUCAPE levels of at least 500-1000 J/kg are suggested by ensembles Sunday afternoon, with a lot of that in the ideal hail growth zone. 0-6km shear may top out in the range of 50-60 knots. As another cold front drops across the region during the afternoon and evening, some supercell structures may be supported in this environment, with all severe hazards on the table. At present, parameters appear best aligned in eastern Ohio and leaking over into southwestern Pennsylvania. Accordingly, SPC has expanded the Slight Risk (level 2 of 5) into southwestern Pennsylvania, with a Marginal Risk (level 1 of 5) encompassing the rest of our area. Weakening convection would accompany the front through the night, with dry weather and cooler temperatures returning for Monday. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... Southwesterly wind gusts persist today ahead of a surface cold frontal passage. Rain has already began aloft, which will progressively filter its way to the surface at ports over the next couple hours. Through 00Z, showers will be hit or miss, and while thunder couldn't be completely ruled out, its generally less than 20% likely at any given port. Along/behind the front itself, the environment may be a bit more unstable, but there is a low probability of convective development, therefore, maintained PROB30 groups at any ports where an isolated thunderstorm is most possible after sunset. Into tonight, recent rains and saturation in wake of the front will allow the chance of widespread MVFR cigs, with a chance of IFR at DUJ/FKL. Dry air advection in wake of the front will progressively improve cigs into the morning hours Saturday. Widespread return to VFR are likely by 16Z. Outlook... VFR cigs return late morning Saturday. A frontal passage Sunday could return strong thunderstorms to the region during the afternoon. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...MLB/CL AVIATION...Milcarek