Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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172 FXUS61 KPBZ 241619 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1219 PM EDT Fri Jul 24 2026 .WHAT HAS CHANGED... Few changes for the long-range forecast. && .KEY MESSAGES... 1) The highest chance of severe weather over the next week occurs on Monday and Tuesday with increased potential for Mesoscale Convective Systems (MCSs). && .DISCUSSION... KEY MESSAGE 1... A weak mid-level shortwave trough may drop across the area this evening, in an environment where even the "high-end" CAPE will be a couple hundred J/kg. Given the weak forcing and low instability, a few showers and storm day develop, though severe threats are not anticipated. The same can generally be said for Saturday afternoon, though CAPE may be a bit higher (up to 1000 J/kg), though dry air aloft and a subsidence inversion favors keeping convection shallow. SPC and ML outlooks to not favor severe development. Sunday, only a low chance for severe weather exists. Mid level flow and organized storms favors tracks over the midwest to west-central Ohio. The potential of storms only exists on some lake boundary or outflow, but even then sfc-6km flow is quite slow (>20kts), and DCAPE decreases as moisture returns with LREF 50th percentile DCAPE ~600 J/kg, assuming a parcel maximizes its potential. If anything, this would allude to a marginal flood threat. That being said, if substantial upper level wind forecasts change, resulting in increasing MCS potential to the east of the current forecast, our chances would go up locally. The potential for widespread strong to severe storms becomes more favorable Monday into Tuesday as the ridge over the northern Great Lakes weakens, opening the door for upstream MCSs to propagate into the region or that remnant outflow boundaries of decaying MCSs redevelopment during peak heating. If mesoscale convective systems (MCSs) do develop and track into our region, forecast soundings indicate an environment capable of supporting all severe weather hazards, including hail, damaging wind gusts, tornadoes, and heavy rainfall. And most importantly, there is low confidence in when if if these should occur locally. NCAR Machine-learning guidance has a 5-10% of severe weather over our region on Sunday; 15 to 45% chance for Monday and Tuesday. Colorado State University (CSU) machine learning has 5-15% chance of excessive rainfall (flash flooding) Monday into Tuesday. The Weather Prediction Center has issued "Marginal" (1 out of 4) risks for back-to-back days. The eventual evolution of this threat will largely depend on the amplitude of the eastern U.S. trough and the strength and position of the upper- level ridge, which will influence the track and intensity of any MCSs. The threat for severe storms and precipitation is expected to remain low Wednesday into Thursday in the wake of a departing cold front and building high pressure. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... VFR conditions and light southeasterly wind (5-10 kts) will continue to prevail through the TAF period under high pressure. Some lingering cirrus clouds forecast to persist through the day with a scattered CU field likely between 6-8 kft. Tonight, high clouds are expected to lingering. This will limit nighttime radiational cooling and inhibit the development of fog tomorrow morning. Outlook... VFR is expected through Saturday under high pressure. Shower and thunderstorm chances return on Sunday and Monday with an approaching cold front. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...Hefferan/Milcarek AVIATION...Lupo