FXUS61 KPBZ 261657

AFDPBZ



Area Forecast Discussion

National Weather Service Pittsburgh PA

1257 PM EDT Thu Jun 26 2025



.SYNOPSIS...

Hot and humid through the end of the week with daily afternoon 

storm, isolated flooding, and severe wind chances. Rain chances

decrease Sunday, followed by another active period Monday to

Tuesday before temperatures return to near normal and conditions

trend slightly drier mid-week.



&&



.NEAR TERM /THROUGH TONIGHT/...

KEY MESSAGES:



- Heat concerns continue through the afternoon for most of the

  area, with indices approaching 100F, hottest for valley and 

  urban locations.

- A marginal chance of severe wind and flooding into the 

  afternoon and evening with downburst potential.

---------------------------------------------------------------



Heat concerns linger through the period with mostly the effects

of cumulative heat stress. While we anticipate that heat will

not be as warm as days prior (40% to 80% chance of heat 

indices >95F in the Heat Advisory Area). Impacts will be 

highest for valley and urban locations given anticipated highest

heat indices and stresses on existing infrastructure. 

Additionally, the impacts may be higher for areas that do not 

receive rain and are not impacted by a cold pool, though the 

exact locations remain low confidence up to a couple hours 

before occurrence. In areas impacted by rain or cooler 

temperatures, there may be some relief this afternoon. 



As for the severe threat, the 12Z morning sounding has shown a

mostly saturated profile with weak, generally westerly, flow.

DCAPE is not as stark as the day prior, but SPC mesoanalysis

shows pockets of 800 J/kg to 1000 J/kg moving overhead with

roughly 1500 J/kg to 2000 J/kg of MLCAPE. A mature cell in this

environment will be capable of producing downburst wind 

threats. RAP analysis indicates a freezing level of roughly 

13kft as of noon and the -10C to -30C layer between 19kft and 

28kft. A developed cell ingesting liquid water in an updraft 

into this level would be most opportune to develop an icy core.

The higher the cell develops and the broader the cell is, the 

moore likely severe criteria may be met at the surface when the 

core falls out.



In tandem with the wind threat will come the flooding threat.

The morning sounding still has an anomalously high 1.68" PWAT

reading. With weak westerly flow, we would expect storms that

develop on the west side of cold pools (up-shear) to be mostly 

stationary. Unlike yesterday, flow aloft is westerly, so anvils

may blow east and leave this side of developed cells in

comparatively clearer skies, and potentially more instability.

These reasons are all supportive of an afternoon/evening flood

threat that slightly lags the severe threats. 



Development is generally expected in the 1pm to 3pm timeframe as

the convective temperature in the upper 80s are reached. The

most likely area for development today may be along the rugged 

cumulus between Cleveland and Pittsburgh, perhaps aggravated by

an inland penetrating lake boundary. A secondary area may be

rugged cu moving in from Columbus, OH.



Into tonight, convective coverage is expected to drop off,

though elevated instability may keep a very isolated shower or 

two. Nonetheless, threat chances would be lower should any rain

develop. Dew points in the upper 60s and low 70s will keep 

temperatures anomalously warm, with a 30% to 70% chance of 

staying above 70F overnight, highest for the urban and valley 

areas. This has justified the continuation of the heat advisory 

with cumulative heat stress.



&&



.SHORT TERM /FRIDAY THROUGH SATURDAY/...

KEY MESSAGES:



- Heat concerns continue on Friday; heat advisory will be in 

  effect through 8pm Friday.

- Daily downburst wind and flooding threats in the afternoon and

  evening continue through at least Saturday.

----------------------------------------------------------------



On Friday, chances of heat indices exceeding 90F are generally 

60% to 100% within the heat advisory, and there is roughly a 50%

chance of exceeding indices of 95F in valley and urban 

locations. Again, we expect this to follow a downtrend in 

temperatures we have been seeing since Wednesday, but the main 

point for continuing the advisory is cumulative heat stress.



A for impactful weather, the environment will generally be

unchanged from the days prior. SBCAPE will be between 2000 J/kg

and 2500 J/kg, shear will likely be light (<=10kts) and from 

the west both south and west of Pittsburgh, with higher values 

toward the ridges, and DCAPE may be between 600 J/kg and 800

J/kg (ranges determined by 25th and 75th HREF percentiles). 

This will once again be supportive of a downburst wind threat in

mature cells, and a flooding threat on up-shear development of 

cells, particularly including northern WV, eastern Ohio, and the

far southwest corner of PA.



Again development is expected to die down overnight with a loss

of heating, and the heat advisory will be allowed to expire at

8pm as temperatures cool and Saturday temperatures to not near

advisory criteria. 



Saturday, a boundary sinking from the north in a similar

environment will continue to allow for downburst wind and

flooding threats. LREF mean analysis shows 1500 J/kg MLCAPE, 650

DCAPE, and PWATS back up near 1.8" to 1.9" in moisture pooling

along the boundary. Perhaps given the environment and slow

southward sagging boundary, flooding threats may be a bit higher

than days prior, depending on the coverage, with increased

training potential.



&&



.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...

KEY MESSAGES:



- Potential for storms and locally heavy rainfall through at

  least Monday and possibly on Tuesday.

-------------------------------------------------------------------



The boundary is forecast to sag south of Sunday with ML

techniques suggesting lower probabilities of severe weather, and

any chances of flooding most likely for northern West Virginia 

in the vicinity of the boundary. 



Monday, at least some return flow is expected as the boundary

draws back north. Southwest flow prevails with increasing

precipitation chances yet again as temperature spreads are 

mostly encompassed in the upper 80s to low 90s. Once again, this

will allow more wind and flooding threats. 



A frontal passage is forecast sometime late Monday into Tuesday

that will maintain flooding chances before a cold front finally

clears the oppressive airmass out with a return to more normal

temperatures and moisture for mid-week. Clusters indicate this 

pattern change, at least temporarily, is high confidence. 



&&



.AVIATION /18Z THURSDAY THROUGH TUESDAY/...

Patchy fog has plagued a few sites this morning, mostly those

that saw rain yesterday, with restrictions ranging from MVFR

down to LIFR with light wind and clear skies. Expect that as we

heat this morning, mixing will quickly commence and allow for

any restrictions to diminish within an hour to two after

sunrise.



Scattered thunderstorms are expected to develop this afternoon

and evening in a similar manner to Wednesday as convection 

fires in the vicinity of a quasi-stationary front across the 

region. Included a prob30 for thunder, variable wind gusts, and

associated restrictions at all airports during the most likely 

time of occurrence.



Convection should wane again this evening with the loss of

daytime heating and diurnal instability. Mid-level clouds 

should linger into the evening with VFR expected. 



Outlook... 

Patchy MVFR/IFR in fog/stratus is expected Friday morning with

low level moisture in place. More numerous showers and

thunderstorms are expected Friday and Saturday afternoon and 

evening asthe front wavers across the region. 



There is a lesser potential for afternoon showers/storms on 

Sunday as high pressure briefly brushes by to the north. 

Showers/storms return again Monday with an approaching cold 

front.



&&



.CLIMATE...

Daily record high maximum (left) and daily record high minimum (right)

temperatures for Thursday are listed below.



Thursday June 26th

Pittsburgh, PA:         95F (1966)              75F (1952)

Zanesville, OH:         97F (1952)              73F (1952)

Morgantown, WV:         96F (1952)              74F (1952)

Dubois, PA:             91F (1966)              66F (2000)

Wheeling, WV:           96F (1943, 1952)        73F (1952)

New Philadelphia, OH:   99F (1988)              71F (2022)



&&



.PBZ WATCHES/WARNINGS/ADVISORIES...

PA...Heat Advisory until 8 PM EDT Friday for PAZ013-014-020>022-029-

     031-073-075.

OH...Heat Advisory until 8 PM EDT Friday for OHZ039>041-048>050-

     057>059-068-069.

WV...Heat Advisory until 8 PM EDT Friday for WVZ001>004-012-021-509-

     510.



&&



$$



SYNOPSIS...Milcarek

NEAR TERM...Milcarek

SHORT TERM...Milcarek

LONG TERM...Milcarek

AVIATION...WM/MLB

CLIMATE...MLB

