


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
39
40
41
42
43
44
45
46
47
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --418 FXUS61 KPBZ 300457 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1257 AM EDT Mon Jun 30 2025 .SYNOPSIS... Shower and storm activity will remain focused south of Pittsburgh, near a stationary front. Scattered storm chances increase tomorrow, a few storms could produce damaging winds and/or flooding. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... KEY MESSAGES: - Isolated shower and/or storms will be focused south of Pittsburgh today - Patchy fog possible tonight --------------------------------------------------------------- A persistent area of low-level cumulus clouds remains over the central part of our forecast area, tied to a stationary boundary positioned between Morgantown, WV and Pittsburgh, PA. With surface heating over the next 6 hours, clouds are expected to slowly dissolve--becoming more broken and scattered opposed to overcast. Just south of the stalled boundary, also expected isolated showers and/or storms south of the forecast area. The convergence appears weak in the boundary layer with little advancement of the front, so confidence on storm occurrence is low. However, the terrain may help create the lift necessary to generate isolated convection between 2pm and 7pm. Tonight, little change is expected with temperatures dropping into the upper 60s/lower 70s. Patchy fog will again be possible as low-level moisture lingers, though increasing cloud cover should keep this from being widespread. If there is fog, high resolution models are noting areas south of Pittsburgh--likely near the stationary boundary. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... KEY MESSAGES: - Strong to severe storms and heavy rainfall chances return Monday and Tuesday. - Temperatures remain above-average, but below Heat Advisory criteria. ---------------------------------------------------------------- High pressure over the Ohio River Valley will gradually weaken as an upstream disturbance--currently over the Great Plains-- tracks eastward over the next 24 hours within a zonal upper- level flow. Afternoon and evening showers and storms will likely return Monday; mainly after 12pm. Heavy downpours and damaging wind gusts associated with downbursts will be the main threat. Training storms, particularly over urban areas, will be the primary concern, with isolated storms capable of producing rainfall rates exceeding 1 inch per hour. DCAPE values are expected to range between 400-600J/kg, through there`s a noticeable lack of dry air below 500mb--likely a result of lingering outflow aloft from upstream convection to our west or southwest. However, high-resolution models indicate an increase in mid-level shear (800mb-700mb) between 19Z to 23Z, which could support stronger updrafts. On Tuesday, a cold front and accompanying trough moving through the Ohio River Valley will likely trigger organized showers and thunderstorms. With a tropical airmass in place, heavy downpours are expected. However, increased vertical wind shear should help storms move quickly, reducing the flood risk. The Storm Prediction Center (SPC) has placed areas east of the PA/WV ridges under a Marginal Risk. If the front slows down, the threat for severe storms could expand into western Pennsylvania and northern West Virginia. && .LONG TERM /THURSDAY THROUGH SUNDAY/... KEY MESSAGES: - Cold front Thursday brings back showers and storms. - July 4th holiday looks dry. - Rain chances return late next weekend. ------------------------------------------------------------------- A shortwave will churn through the ECONUS longwave trough on Thursday and kick a cold front through the area from the northwest. Timing remains a bit uncertain, but passage is likely some time on Thursday which will return the chance for showers and storms. Dew points ahead of it look to sit in the low 60s with not much return flow on Wednesday, but the NBM prob for >1000 J/kg SBCAPE is around 40-50% in the afternoon hours. Deep layer shear may be the lacking component with the best forcing and flow displaced to the north with the shortwave. Still, machine learning does peg at least a low-end chance of severe weather with the passage, contingent on it being at a favorable diurnal time. Headed into the fourth, ensembles are in good agreement on a return of mid-level ridging behind the departing longwave. Some subtle timing differences arise with how quickly the ridge builds which suggests that high temperatures are lower confidence right now as supported by the NBM MaxT spread of 6 degrees at PIT. Rain chances are low in any scenario at less than 20% with dry air advecting in in the wake of Thursday`s boundary. The ridge flattens out into the weekend with a mid-level zonal flow pattern taking over. Ensembles do agree on low pressure development across the Northern Plains sometime Friday into Saturday and quickly sliding east, but disagreement on timing lends low confidence precipitation chances locally as the attendant surface cold front follows along with it. Most of Saturday looks dry at this time with even the faster solutions holding precip chances off until early Sunday, so most likely will see a more unsettled pattern return for the latter half of the weekend and into next week. Temperatures around average through the second half of the week may warm to slightly above average for the weekend. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...-- Changed Discussion --VFR is expected tonight as mid and high level clouds cigs continue ahead of an approaching shortwave trough. CU rule and model soundings indicate a diurnal cumulus layer will develop by mid to late morning as convective temperatures are reached. Numerous showers and thunderstorms are expected to develop by early to mid afternoon as a shortwave trough crosses the Upper Ohio Valley region, and as a surface boundary lifts north. CAPE is expected to range from 1000-2000 j/kg as the wave crosses, with 0-6km shear near 40kt. Included TEMPO for thunderstorms at all airports for the most likely time of occurrence, with PIT generally 19Z-23Z. Included MVFR restrictions for now, though IFR will be possible in locally heavy rainfall. Convection should gradually wane this evening with the loss of diurnal instability, and as the shortwave exits. Outlook... Fog and stratus restrictions are possible tonight with low level moisture in place. A crossing cold front will result in numerous showers and thunderstorms again on Tuesday afternoon and evening. VFR returns Wednesday under high pressure, before restriction and thunderstorm potential returns with a Thursday cold front. VFR is expected again by Friday under high pressure.-- End Changed Discussion --&& .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...Rackley NEAR TERM...Hefferan/Rackley SHORT TERM...Hefferan LONG TERM...MLB AVIATION...WM