887
FXUS61 KPBZ 211203
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
703 AM EST Fri Nov 21 2025

.SYNOPSIS...
Foggy conditions this morning. Probability of rain increases
late this evening and continues into early Saturday. Mild
conditions are likely this weekend and into early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
- Dense Fog Advisory through 9am
- Probability of rain increases after sunset

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

4:30am Update:

With several surface observations dropping below one-half mile
visibility for an extended period, the Dense Fog Advisory has
been expanded to include counties west of the Laurel Highlands.
Pittsburgh, Wheeling, Washington, and Morgantown are now the
Advisory through 9am.

Previous Discussion:

With weak advection in place early this morning, the risk
of fog remains elevated. A Dense Fog Advisory continues for
locations east of Pittsburgh, including the Laurel Highlands,
where visibilities have fluctuated between one-quarter and one-
half mile over the past few hours. Areas in eastern Ohio and
near the Pennsylvania- West Virginia border will be monitored
for a possible expansion of the Advisory.

The threat for fog will likely rapidly decrease between 9am and
10am with diurnal heating promotes boundary mixing.

A weak trough passing near Lake Erie may produce a brief period
of light rain or drizzle north of Pittsburgh near dawn. A more
persistent rain is expected later tonight as a low pressure
system approaches from the southwest. Overall rainfall totals
should remain light, ranging from a trace to 0.3 inches through
midnight.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
KEY MESSAGES:

- Drier conditions expected Saturday with seasonable
  temperatures
----------------------------------------------------------------

Rain will likely persist past midnight early Saturday as the
previously mentioned disturbance moves through the region.
However, precipitation chances quickly diminish from west to
east between 4am and 6am as a cold front sweeps across Lake
Erie.

Increasing subsidence in the low and mid levels associated with
building high pressure should thin cloud cover by Saturday
afternoon. Still, extended periods of sunshine may be limited at
times due to ongoing cold advection over the Great Lakes.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
KEY MESSAGES:

- Dry and mild Sunday into Monday
- Precipitation chances return Tuesday into Wednesday
- Cooler pattern expected Thanksgiving
-------------------------------------------------------------------

Long-range models over the last 24 hours continue to show ridge
development over the Great Lakes from Sunday into Monday. This
pattern support mild, dry conditions during the afternoon hours.
However, with the potential of overnight clearing and lingering
dry air near the surface, temperatures are expected to fall back
toward climatological average--hovering near or just above
freezing during the early morning hours of Sunday and Monday.

Precipitation chances increase Tuesday into Wednesday as a
trough shifts form the Midwest and into the Great Lakes, drawing
warm, moist air northward from the southwest into the Ohio River
Valley. Rainfall totals may be limited, especially if a dry
slot pushes into the region early Wednesday. The probability of
receiving a half inch of rain within 24 hours remains below 10%.

More than half of the long-range models indicate a pattern shift
developing late Wednesday into Thursday, as broad ridging over
Alaska and the West Coast reinforces a large-scale trough across
the Great Lakes. This setup favors a return to below-average
temperatures and an increased potential for lake-enhanced snow.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Widespread LIFR conditions are ongoing across the area to start
the 12Z TAF cycle due to a combination of fog and low stratus.
Similar to recent days, not much improvement is expected
over the next couple hours. Gradual mixing and dissipating of
fog should begin in the 14z-16z timeframe, but the process will
be slow and overall categorical improvements may not amount to
much as low stratus lingers at the high-end IFR/low-end MVFR
range. Rain is favored to overspread the area late this
evening (likely after 00z), but occasional instances of light
drizzle are possible this morning and afternoon.

Outlook...
Rain is favored tonight into Saturday morning with the greatest
restrictions/rainfall accumulations occurring around/south of
Pittsburgh. MVFR/IFR will be highly likely in areas of rain,
with some potential for near VFR conditions at FKL/DUJ which
will be on the northern periphery or just outside of the rain.

There is high confidence of VFR under the influence of high pressure
beginning Sunday morning until the next low pressure system arrives
near Tuesday.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Dense Fog Advisory until 9 AM EST this morning for PAZ009-015-
     016-021-022-029-031-073>078.
OH...None.
WV...Dense Fog Advisory until 9 AM EST this morning for WVZ002>004-
     509-510.

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan
SHORT TERM...Hefferan
LONG TERM...Hefferan
AVIATION...Cermak/AK