199
FXUS61 KPBZ 142343
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
743 PM EDT Mon Jul 14 2025

.SYNOPSIS...
Relatively drier weather is expected Tuesday, then additional
rain with severe weather and flood chances to close out the
week. Temperatures will remain above normal.

&&

.NEAR TERM /THROUGH TUESDAY/...
KEY MESSAGES:

- Rain and flooding chances today.
- Dense fog possible tonight.
---------------------------------------------------------------

This afternoon, the area will sit south of a surface boundary
that gradually pushes south into the day. This had led to some
low level convergence in air with an observed 1.75" PWAT (90th
percentile), resulting in fairly widespread rain with embedded
convective elements where saturation wet-bulbed the sfc to 600mb
layer. Because most of this activity is below freezing, almost
all rain is following warm rain processes. As a proxy for where
most of the convection is, the sfc-3km mean wind is observed at
2kts as of 12Z. All of these elements will come together to
increase a flooding risk this afternoon/evening.

If there is an area to watch, it will primarily be the boundary
sagging south, allowing for enhanced convergence and higher
precipitation rates. Along the boundary, flooding has already
been observed south of New Castle (2" to 3" per hour rainfall
rates), showing the atmosphere is already capable. As the
boundary pushes south, the timing of the threat may be maximized
in southwest PA the northern WV panhandle, and southeast Ohio
between 2pm to 7pm, before threats may maximize in the rest of
northern West Virginia in roughly the 4pm to 9pm timeframe,
though flooding cannot be rules out anywhere south of the
boundary at any point. This timing matches a combination of
frontal position and maximized solar heating and instability
generation through the day.

In line with what has already been observed and HREF maximum QPF
totals, we might expect the high-end amounts in tropical rain to
get close to 2" to 3" per hour, topping the rough 1.25" to 2"
per hour FFGs. WPC has expanded the slight risk ERO across much
of southwest PA and northern WV at the most recent update, with
the highest probabilities of flooding toward the ridges. With
plenty of moisture, severe chances remain very low today.

As the front continues to sag south, return flow and an eastern
low development may cause it to stall somewhere in the
periphery of I-70 overnight, while rain could not be rules out
completely in high moisture along a forcing axis, in general,
the loss of daytime heating will preclude any notable
probabilities overnight. On the other hand, with dew points in
the upper 60s and low 70s behind the front with some cloud
clearing, calm winds, and recent rains promoting high surface
soil moisture, this may support locally dense fog overnight.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
KEY MESSAGES:

- Warmer with lower rain chances north of I-70 Tuesday; chance
  of rain and flooding near and south of I-70.
- Increasing heat impacts, flood chances, and severe chances
  Wednesday and Thursday.

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

As mentioned before, the front will sit relatively still
somewhere across the area into Tuesday, Wednesday, and Thursday
which will allow a continued active pattern.

Tuesday will likely be the most quiet day of the lot, with drier
air filling in in subsidence aloft behind the front and through
parts of the forecast area, which may keep skies mostly clear,
most likely north of the front, which is most likely to reside
around I-70. This will lower PWATS; with little forcing
precipitation and especially flooding chances will be quite low.
This will allow heat to creep back in, with forecast highs a few
degrees warmer than Monday (into the upper 80s and low 90s).
Some major heat risk may creep back in for urban and valley
locations. South of the front, which again, is likely going to
be somewhere in the I-70 corridor, some residual moisture and
weak convergence along the stalled boundary in modeled 1.5" to
1.7" PWATs (near Morgantown) with weak flow will continue
marginal flash flood mentions. Perhaps the highest local chances
will be along the WV ridges with ridge-top convergence and
forced ascent. Little temperature recovery is expected overnight
with lows bottoming out near or above the 70F mark.

Wednesday, the boundary will again remain, expect there may be
a bit of return flow with some overrunning of the boundary
possible. This will allow flood risks to perhaps continue, as
the stalled front may come back north as a warm front. With
this, moisture, clouds, and storm chances return. With drier
air on the north side of the front, it seems there may be a
chance of flooding and severe weather during the day. The flood
risk is a bit more concrete with another push of 90th
percentile PWATs on a boundary in flow generally weak flow
(<10kts in the cloud layer). This will be most likely along and
south of the front, but will depend of the frontal placement.
Chances may be the highest south of PIT in the morning/early
afternoon, pushing through and north of PIT in the
afternoon/evening. Severe appears marginal, but occurrence will
rely on the presence of dry air aloft north of the front and
overrunning to realize a downburst wind threat. This increase
of severe chances Wednesday is supported by CSU/NCAR ML and
CIPS analogs. Because it will rely on dry air, chances may be a
bit high around and north of PIT. Cloud cover chances have
increased a bit Wednesday, witch may both complicate
instability generation, and has also dropped the max temperature
forecast slightly, though cumulative heat stress will linger,
particularly for valleys and urban areas with heat risk
maintaining moderate/major mentions. Again, little recovery is
expected with lows in the 70s expected for most.

Thursday, th region will be solidly in the warm sector, with
another fount forecast off to the north somewhere in the
vicinity of the lower Great Lakes. Another push of the pre-
frontal, warm, and moist southwest flow will keep cognitions
muggy and warm, with moderate/major heat risk lingering. While
CIPS and ML linger some low probabilities of severe win the
warm sector, LREF mean PWATS pushing 2" in long, skinny CAPE
might allude to more of a continued, area-wide flood risk.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
KEY MESSAGES:

- Frontal passage on Friday will bring more seasonable
  temperatures.
- A return to warm and wet expected next week.

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

Friday, the environment will be similar to Thursday before the
cold frontal passage. The frontal passage Friday seems a bit
more guaranteed than the prior update, but passage timing is
slightly uncertain, with some ensembles moving it through in the
morning, while others have it crossing as late at the evening.
This will affect flood chances, severe chances, and
temperatures. An earlier passage would mean lower chances of
flooding/severe and keep temperatures near normal of Friday,
while a later passage would provide warmer highs and higher
severe/flood risks.

The pattern remains in good agreement through the weekend and
into next week. This would suggest the front comes back north as
a warm front over the weekend, and the region stays in quasi-
zonal flow with above average temperatures, continued rain
chances, and non-zero flooding severe chances depending on the
timing or amplitude of various shortwave passages. Long storm
short, the pattern may remain the same for a little while
longer.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Rain has ended this evening behind the shortwave and lingering
scattered Cu are diminishing with sunset. This clearing with
residual low-level moisture should result in increasing
fog/stratus development overnight, with IFR to LIFR at most
terminals. The fog should mix out Tuesday morning, with VFR
returning. CU rule and model soundings indicate a scattered to
broken diurnal cumulus layer should develop by mid to late
morning, continuing into the afternoon. Most airports should
remain dry Tuesday afternoon, though MGW and LBE could see lower
chance of a late day thunderstorm as a stationary surface front
sets up to the south of I-70.

Fog may be possible again Tuesday night, especially in locations
that see rainfall Tuesday afternoon.

Outlook...
Daily shower and thunderstorm chances are expected to continue,
especially in the afternoons and evenings, as a quasi-
stationary front drifts across the region. Early morning fog and
stratus is also possible, especially where rainfall occurs in
the afternoon and evening.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

$$

SYNOPSIS...Milcarek
NEAR TERM...Milcarek
SHORT TERM...Milcarek
LONG TERM...Milcarek
AVIATION...WM/Rackley