Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
007 FXUS61 KPBZ 221140 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 740 AM EDT Sat Aug 22 2026 .WHAT HAS CHANGED... Higher confidence in the timing and scope of thunderstorm activity this afternoon and evening results in higher probability of severe weather occurring. SPC also introduced a low probability damaging wind threat for Sunday near the I-80 corridor/ && .KEY MESSAGES... 1) A slight risk exists for damaging wind and large hail threat with storm activity this afternoon and evening. 2) A marginal risk for damaging wind Sunday is tied to afternoon and evening convection near the I-80 corridor. 3) Outside of lingering showers near Lake Erie, dry weather favored through mid next week. && .DISCUSSION... KEY MESSAGE 1... Outside of a loner, elevated storm in north central OH, the overnight period has seen the pre-frontal convection die off east of the region while the MCS remains farther west in central IL. This results sets up the region to remain in a clearer sky environment that awaits the arrival of the pre-frontal trough (and eventual sfc cold front) to initiate fairly widespread showers and thunderstorms. Hi-res guidance has generally coalesced around the idea of storm initiation between 2pm-4pm over eastern OH with storms spreading east through 8pm along/ahead of the pre-frontal trough before lingering showers and low probability thunderstorms full push east of the region by the early hours Sunday morning ahead of the surface cold front. Clearer skies allowing for maximization of surface heating should push area SBCAPE values towards 1500-2000 J/kg and steepens low-level lapse rates that serves as the main drivers for the hazardous weather threat. Despite weak shear (around 20kts) and marginal dCAPE (600-800 J/kg) that should limit the high-end severe potential, discrete storms that merge into multicellular clusters is enough to create scattered instances of damaging winds and large hail. Severe threats peak between 4pm-8pm before subsiding thereafter as buoyancy wanes and the surface decouples. KEY MESSAGE 2... Residual shortwave movement combined with cold advection aloft may trigger isolated to scattered showers and thunderstorm Sunday afternoon and evening coincident with peak heating. Storms coming off Lake Erie toward the I-80 corridor may pose an isolated damaging wind threat if surface heating maximizes sbCAPE (to 1000 J/kg) while mid-level flow strengthens. KEY MESSAGE 3... Residual cool northwest flow on the backside of the upper trough may induce enough lift in conjunction with warm Lake Erie waters to create light rain showers near/north of I-80 late Sunday into Monday. Otherwise, high pressure and height rises aloft point to a prolonged (relatively speaking, in relation to the previous month) dry period to start next week. High temperature does start below seasonal averages on Monday before rising back near average by mid week. Long range ensembles currently favor Thursday as the next day with showers/thunderstorms as the next upper trough crosses. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... High confidence forecast of VFR and medium confidence of showers and storms impacting airports, however there will be storms around this afternoon and early evening. VFR prevails, otherwise until widespread showers and thunderstorms develop this afternoon and evening ahead of an advancing pre-frontal trough (1st) and cold front (2nd) combo. The strong storms could drop visibilities to IFR levels while also posing a risk for creating wind gusts to at least 30kts, potentially higher. Based on the latest high resolution models, the time window is 18-22Z in Ohio, 20-24Z PA and WV save for DUJ where it is until 2Z. Lingering shower and low probability thunderstorms eventually clear east by 06z, but cool advection plus residual moisture favors MVFR/IFR stratus development thereafter. Current probs have a 30-40% of IFR CIGS over PA and WV. The highest confidence now is our historically more frequent terminals of FKL and DUJ. Outlook... Widespread MVFR to IFR cigs are favored Sunday morning that improve through the day, but scattered showers and low probability thunderstorms develop by the afternoon due to cool NW flow over warm lake waters. Precipitation chances linger in northwest PA into Monday before high pressure provides areawide VFR dry weather by Tuesday. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...Frazier AVIATION...Frazier/McMullen