FXUS61 KPBZ 170615 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 215 AM EDT Fri Apr 17 2026 .WHAT HAS CHANGED... The severe weather threat for Saturday has been expanded to include almost the entire forecast area in a Slight risk. A tornado threat has been included as well. && .KEY MESSAGES... 1) A cold front Saturday afternoon and evening will bring another round of strong to potentially severe thunderstorms. Damaging wind again appears to be the most likely threat although a tornado and large hail threat is also possible. 2) Much above-normal temperatures continue until the Saturday cold front passage. Behind it, temperatures crash to much below-normal levels. Frost/freeze concerns return by early next week, and even a few Sunday night snowflakes are possible. && .DISCUSSION... KEY MESSAGE 1... The next system will feature a strong cold front bringing another severe weather episode on Saturday. The current ensembles suggest a situation where the warm front will precede the cold front on Saturday morning into midday. Model sounding ahead of this suggest a dry boundary layer conditioned by the morning convection and prepping the environment for the severe threat later in the day. There are a few concerns, while the warm frontal precip would condition the environment, there may not be enough clearing after the passage for needed destabilization for the higher severe threat. The HREF gives a 40% prob of exceeding 1000 J/Kg SB CAPE. The NBM appears to be more ominous with a 50% to 60% prob of exceeding 1000 J/Kg. Parameters in mind, the SPC has included a 2% tor in the latest Day 2 for Saturday. It would be a good message to consider the overall prob of severe weather in general to have moderate confidence in this occurrence. Especially since the mean for CWASP in the NBM to be 76%. For now, damaging wind confidence is increasing and the tornado prob is quite conditional but with the mention that the threat is certainly there. KEY MESSAGE 2... Much above-normal temperatures continue into Saturday as ridging begins to build back over the region Friday and Saturday ahead of the mentioned front. There may be some modest potential to approach records on Saturday, especially if the front is later than currently projected, allowing for a longer period of warm southwest flow. NBM probabilities of 80 or warmer may be a bit overstated, but much of the area from Pittsburgh south should have at least a 50/50 shot of reaching that level. Meanwhile, behind the front, the script flips, and northeast CONUS troughing leads to daytime high temperatures some 10-15 degrees below normal for Sunday and Monday, before approaching climatology on Tuesday. Frost/freeze products may need to be issued by early next week, and some Sunday night snowflakes are a possibility. Getting back to the low temperatures on Monday and Tuesday morning, confidence is increasing with probs below 32 degrees is near 90% up north and a respectable 50% to 60% for Pittsburgh and south. A hard freeze is not out of the question either but mainly up north. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... Scattered showers and isolated thunderstorms were continuing to move east with a crossing upper level trough. This activity should exit the region by 09Z as the trough moves east. IFR stratus and fog is then expected to develop from N-S across most airports with low level moisture in place, and as radiational cooling occurs. ZZV and MGW will likely not see cigs and are currently expected to stay VFR. Expect an improvement to MVFR cigs by mid morning as mixing lifts cig heights. Clouds should scatter out by early afternoon with VFR returning under building high pressure. A light W-NW wind is expected to veer to the SE Friday evening. Outlook... VFR is expected through Friday night as high pressure moves east across the region. Restrictions in showers and thunderstorms are expected to develop Saturday with the approach and passage of a strong cold front. A few severe storms are also possible. Subsequent upper troughing and cold NW flow should result in cig restrictions and scattered rain showers Saturday night into early Monday. A few snow showers are also possible Sunday night/early Monday. VFR is expected to return later Monday and Tuesday under high pressure. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...Shallenberger AVIATION...WM