FXUS61 KPBZ 152357 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 757 PM EDT Thu Oct 15 2026 .WHAT HAS CHANGED... Rain shower chances have decreased today. Added a mention of thunder on Friday with a strong cold front. A portion of the area generally east of I-79 has been included in a Marginal Risk for severe storms with damaging winds on Friday. && .KEY MESSAGES... 1) Showers, possible thunderstorms, and gusty wind tonight and Fri. 2) Colder behind the front, with frost and freeze conditions Sat night. Frost may be possible again Sun night. 3) Dry and warmer next week, but the forecast has very low predictability at this time. && .DISCUSSION... KEY MESSAGE 1... Storms forming in the Midwest today have a low probability of maintaining strength tonight as a low-level jet and nwd- advancing warm front help maintain only modest stabilization in a moistening boundary layer. If storms are maintained, it will be possible to see a stronger gust or two, but the likelihood of impactful weather tonight remains low. Of greater concern is potential for stronger low-topped convective development on Fri, where buoyancy concentrated in the lower levels of the atmosphere will overlap favorably with convergence within a pre-frontal trough within a moderately sheared environment. There remains timing/positional uncertainty in the placement of the pre-frontal trough convergence zone, with some guidance suggesting a slower progression. If this slower progression materializes, there will be better potential for destabilization as enhanced ascent overspreads the region within a strong mid- level jet streak. Better potential for severe weather exists to the east of the Upper Ohio Valley, but at this time, we cannot rule out the potential for the wrn position of the initiating boundary. If it becomes clear that the boundary is favoring earlier passage, the severe weather threat locally will be minimized. KEY MESSAGE 2... Cold advection in the wake of a strong cold-frontal passage will support renewal of lake-enhanced showers Fri night within a plume of steeper low-level lapse rates. Temperature is not expected to cool sufficiently for notable snow, although low (<10%) chances for snow exist at the highest elevations of the WV ridges thru the weekend. Elevated wind and cloud cover Fri night are likely to preclude frost/freeze concerns, but conditions will become more favorable Sat night as wind slackens and cloud cover dissipates. Cluster analysis suggests two potential H5 patterns that will govern the Sat/Sun evolution: 1) The scenario that is more likely suggests the H5 trough advancing bodily ewd, with cold air building in Sat night leading to widespread temperature in the 30-35F range and potential frost/freeze conditions. 2) A second scenario features low pressure cutting off from the main trough, leading to a quicker departure, less cold air intrusion, and cooler temperature/frost potential favoring mainly the ridges/northeastern most zones. Ensemble Sensitivity Analysis (ESA) suggests that the second scenario is driven by the strength of a H5 ridge currently building in the wrn CONUS, and the timing of phasing of TS Simon into the broader flow. If the ridge is stronger and TS Simon slower to phase, it favors a cutoff low development and warmer outcome as discussed in Outcome 2 above. Monitor the forecast for frost/freeze potential. Greatest confidence in impactful temperature will be the northeastern zones, as temps of 30-35 are most likely there in either outcome above. KEY MESSAGE 3... In the wake of the trough, quite a bit of uncertainty grows with the medium-range pattern next week. Much of the guidance favors a H5 ridge building across the Midwest, suggesting increasing warmth for the Upper Ohio Valley. However, other guidance suggests troughing could develop, which would favor cooler temperature. The degree of ridging or troughing in the east appears highly correlated to the position of a wrn-CONUS trough/potential cutoff low around Mon/Tue timeframe. Given this wide variability and dependence on atmospheric flow features that do not yet exist, the forecast next week has very low predictability, and should be consumed with that awareness. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... The low ceilings have made their way south and LIFR conditions to IFR conditions are in place at the terminals across the area. Winds will light to begin the period but will increase overnight. Overnight, we will also see the wind veer from east to south as conditions remain relatively breezy. By tomorrow morning, areas around PIT and south, are forecast to briefly scatter out by tomorrow morning. During the day, showers and possible thunderstorms ahead of a strong front will bring low MVFR and IFR cigs to areas that were able to scatter out. Wind will freshen up as it veers to the west. Gusts up to 30-40kts are likely with higher gusts up to 45-50kts possible across the higher terrain airports. Restrictions will continue through the day as the cold front approaches. After the brief improvement in conditions roughly around 12Z to 15Z, showers and thunderstorms will form along the front and move through the area through the late morning and into the afternoon. Have used some PROB30s to account for the line of storms midday and into the afternoon. Conditions should begin to improve at least some by 00Z Saturday. Outlook... Showers will continue Friday night under subsequent upper troughing. Building high pressure will return dry weather Saturday into next week. Wind will also diminish on Saturday. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...Kramar/WM AVIATION...Shallenberger/Lupo