899
FXUS61 KPBZ 070930
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
530 AM EDT Tue Oct 7 2025

.SYNOPSIS...
Showers along with a slight chance of non-severe thunderstorms
are expected until Wednesday morning as a cold front crosses
the region. Dry and noticeably cooler conditions will follow in
its wake the remainder of the week.

&&

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

- Areawide rain with 1" to 1.5" forecast over the next 24hrs
- Locally higher amounts possible
---------------------------------------------------------------

Cloud coverage and enough near-surface turbulence has kept
overnight lows relatively high than previous nights, with low
to mid-60s across the region. Light, warm advection driven rain
showers will continue to spread from southwest to northeast
early this morning before becoming more widespread and steady by
the late morning as increased warm advection/isentropic ascent
and convergence along and ahead of a cold front increase
forcing. By this point, PWAT values are progged to reach
1.5-1.75" which is above the 95th percentile of climatology.
Given the ongoing warm advection, deep layer profiles will be
well-saturated and near moist adiabatic. Thus, it`ll be tough to
get much instability going, but warm rain processes with warm
cloud layer depth to around 13kft should still allow for
efficient rainfall. The best overlap of forcing and moisture
will be in the late morning through the evening, so that should
be our window for the steadiest, widespread rain.

In general, latest NBM guidance shows a 10% chance of 2" of rain
over the next 24hrs and a 40-60% chance of greater than 1"
across the region.

Latest flash flood guidance is 4"+, 3-4",and 2-3" for 6hr, 3hr,
and 1hr respectively. Roughly cut that by 1/3 for any metro
areas. WPC has maintained the Marginal risk for flooding
areawide, with a Slight Risk creeping up northwest as far as
Greene county PA.

Overall, a widespread flooding threat is minimal as this should
all fall on a longer timescale with the chance of 1"/hour rates
very low and dry antecedent conditions precluding such a
threat. Some isolated issues in poor drainage and low lying
areas are possible with falling leaves to exacerbate this issue.
Wouldn`t be surprised to see a few rumbles of thunder, but the
poor lapse rates and very low instability lends a low
probability.

Rain will end from west to east with frontal passage, and
lingering low-level moisture and cold advection will likely
result in a stratocu deck, but increasing dry air should erode
the clouds by morning and elevated wind/lowering dew points
should preclude fog development.

&&

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

- Decreasing rain chances into Wednesday morning
- Cooler, drier air mass Wednesday/Thursday offering potential
  for morning frost
----------------------------------------------------------------

High pressure will quickly filter in behind the exiting front
and offer a notable airmass change Wednesday and Thursday. The
resulting increased pressure gradient looks sufficient for 20
to 30mph gusts during the afternoon before tapering off
Wednesday night.

The cooler, drier air mass will result in afternoon highs near
normal on Wednesday, to below average on Thursday despite
mostly sunny skies. This change also creates potential frost
concerns as cooler air plus radiational cooling after low level
winds decouple likely creates lows in the 30s and 40s. The key
limiting factor to any freezing temperature or frost will be
potential for elevated northerly winds from the residual
pressure gradient Thursday morning (and warmer downslope east
wind Friday morning).

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
KEY MESSAGES:

- Dry weather favored through the weekend, though pattern
  variability exists
-------------------------------------------------------------------

There is high confidence in strong surface high pressure
positioning over the New England Friday into the weekend as the
upper Ohio River Valley sits underneath a weak, saggy trough.
This will promote dry weather and gradual warming to about 5
degrees above the daily average through the period.

There remains some uncertainty in this as a potential
developing/deepening coastal low forms near the mid Atlantic and
has potential for inland movement. If confidence in this
scenario exists, an upward trend in precipitation chances along
with a downward trend to temperature (due to increased cloud
cover) for eastern zones could occur.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
Mid level clouds will continue to increase through early morning
ahead of an approaching shortwave trough and its associated
surface cold front. A few light showers are possible before
sunrise as moisture and ascent begins to increase. As the
atmosphere continues to moisten, deterioration to MVFR is
expected from W-E as additional showers overspread the region
later this morning into the afternoon. Delayed the onset of
restrictions as compared to what operational guidance is
depicting, given initially dry conditions. HREF and SREF
probabilities of MVFR/IFR also support a slower deterioration.

Further deterioration to IFR is expected by late afternoon/early
evening as the front continues its approach, and rain continues.
A thunderstorm is possible as well, though instability is
progged to be minimal, with chances too low for a TAF inclusion
at this time. FROPA is expected this evening, with a WSHFT to
the NW. IFR will also continue for some time behind the front
with low level moisture in place.

.OUTLOOK...
After MVFR to IFR restrictions early Wednesday after FROPA, VFR
should then return through the weekend under high pressure.

&&

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

&&

$$

SYNOPSIS...88
NEAR TERM...88
SHORT TERM...88
LONG TERM...88
AVIATION...WM