FXUS61 KPBZ 051707 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 107 PM EDT Tue May 5 2026 .WHAT HAS CHANGED... No significant changes were made to the forecast. && .KEY MESSAGES... 1) Active weather pattern expected through the weekend 2) Frost possible Thursday night / Friday morning && .DISCUSSION... KEY MESSAGE 1... A cold front will slowly (flow is largely parallel to the boundary) drop south across the region with later this afternoon and over the course of the night. Shower and storm chances will progressively increase from the NW this afternoon, but should mainly be confined north of PIT through at least late afternoon. Joint probabilities of CAPE >500 J/kg and shear >30kts is 20-30%, and confined north and west of PGH. SPC has kept the area to just general thunderstorms this afternoon, but if there were any isolated stronger storms, winds would be the primary concern, and they would be north and west of PGH. This would be in the late afternoon / early evening timeframe. Showers and possibly some embedded thunderstorms will become more widespread this evening and overnight as the front continues to slowly drop south across the region. Much cooler temperatures are expected north of the front, with highs near 10 degrees below average. The front should finally exit the region Wednesday evening as flow becomes more northwesterly. A series of shortwaves rotating through broad upper troughing parked over the northeast CONUS will then keep periodic shower chances in the forecast through the weekend and early next week. KEY MESSAGE 2... There is some potential for frost Thursday night and Friday morning though this will be highly dependent on the amount of cloud cover in place and the resulting radiational cooling. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... High confidence VFR through the early evening with southwest wind gusts increasing to 20-30kts. Scattered thunderstorm development between 20z-00z favors an axis from KCMH in OH through KJHW in NY with lowering probabilities for activity bleeding farther southeast (less than 30 percent probability into KPIT, near 0 by KLBE/KMGW). Broad jet-aided ascent ahead of an incoming shortwave plus varied surface low movement ushers in a large plume of light to moderate rain after 00z, with the heavier plume crossing after 06z. There is some variance in the timing of highly likely ceilings falls towards IFR through Wednesday morning, with trends suggesting a slightly later onset versus the previous TAF suggestion. Additional uncertainty in surface low positioning may yield different timing/direction/speed of surface wind, but TAF attempts to capture most likely progression. Dry advection and subsidence will shift the rain axis east through Wednesday morning while area restrictions gradually improve toward VFR through the evening (less than 20% probability of MVFR or lower by 00z Wednesday night, save for 40% probability of stratus lingering near KMGW). Outlook... VFR is favored to start the day Thursday before the next round of precipitation and restrictions return Thursday night into Friday, though primarily for terminals in northwest PA. More widespread rain and restriction development occurs Saturday with on and off periods of rain/restrictions continuing into early next week. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...WM/Rackley/88 AVIATION...Frazier