616
FXUS61 KPBZ 090736
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
236 AM EST Tue Dec 9 2025

.SYNOPSIS...
Active weather pattern through the weekend will bring rounds of
snow, occasionally mixed with rain, as well as fluctuating
temperature and gusty winds. Overall, snowfall accumulations
favor areas north of Interstate 80 and the ridges of southwest
Pennsylvania and northern West Virginia.

&&

.NEAR TERM /TODAY AND TONIGHT/...
KEY MESSAGES:

- Weak, fast moving disturbance brings light snow to northwest
  PA this afternoon with only light accumulations
- A second, fast moving disturbance brings a quick 2 to 4 inches
  of wet snow to areas along and north of I-80 after Midnight
- Seasonably cool temperatures continue
---------------------------------------------------------------

A weak shortwave currently crossing the northern Great Lakes is
expected to drop through the lower Lakes by this afternoon and
evening. As high pressure slides to the Atlantic Coast in
response to its approach, weak warm advection will lift area
temperatures to the mid 30s. Meager moisture profiles and weak
jet-ascent will limit this system`s precipitation shield to
areas along/north of I-80; timing of the passing wave and weak
frontal boundary favors a 2pm onset and 7pm exit. Thermal
profiles favor all snow, but the lack of deeper moisture/strong
lift and marginal surface temperatures right around or possibly
even a degree or two above freezing mean probabilities of
exceeding 1 inch of accumulation is low (15-30%). Any lingering
precipitation during late evening hours should be even lighter
and generally non-accumulating.

Rapid transition occurs Tuesday night as a deeper upper trough
enters the Great Lakes region hot on the heels of the afternoon
wave. A stalled front from the Tuesday afternoon wave lifts
northward as a warm front as southwest flow develops ahead of
the approaching low. Strengthening jet-aided ascent along with
the warm front will aid precipitation development into northwest
PA and eastern OH during overnight hours. With deeper moisture
and better ascent aligning north of the front, a second, heavier
wave of snowfall is expected along and north of the I-80
corridor generally after Midnight through dawn. A Winter Weather
Advisory is now in effect for these areas starting at 1 AM EST,
with a quick 2 to 4 inches of wet snow possible overnight
through dawn Wednesday. Areas between the I-80 corridor and
Pittsburgh may see 1 to 2 inches during that time as well, while
warming thermal profiles farther south limit accumulations as
rain mixes in with snow.

&&

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

- Stronger low Wednesday features a mix of rain and snow that
  will transition back to all snow Wednesday night
----------------------------------------------------------------

Precipitation spreads areawide on Wednesday as the upper trough
continues to dig eastward across the Ohio Valley and large-scale
ascent overspreads the region. Precipitation type will be a bit
more tricky given the aforementioned warm advection, but overall
confidence remains relatively high in any accumulating snowfall
remaining north of Pittsburgh and in the ridges during daytime
hours while elsewhere all rain or a rain/snow mix will result
in little to no accumulation. A transition to rain or a
rain/snow mix will be latest for northwest PA and the higher
terrain southeast of Pittsburgh, where it may not occur until
late afternoon if at all. Until this occurs, accumulating wet
snow is likely and favoring these areas.

If a transition to rain or rain/snow does occur north of I-80
during the afternoon, it will be rather short lived as winds
shift to northwesterly by evening and cooling thermal profiles
return snow (possibly with some lake enhancement) through late
evening. An additional 1 to 2 inches of localized snowfall will
be possible during that time. As such, the Winter Weather
Advisory that starts at 1 AM EST Wednesday is not set to expire
until 10 PM EST Wednesday, and could be extended a bit further
if lake-enhanced snow showers linger into Wednesday night.

Meanwhile, in the ridges of SW PA and northern WV, there is some
potential for snowfall accumulations to reach 3 to 5 inches,
though no headlines have been issued yet as it would be
beneficial to wait until additional guidance (especially from
higher resolution convective-allowing models) later today allows
for those decisions to be made with higher confidence. That said,
in the higher ridges of eastern Tucker County (WV), where snow
may never change over or mix with rain, latest ensemble guidance
suggests at least a 50% chance for total snowfall accumulations
to reach or exceed 6 inches, prompting the issuance of a Winter
Storm Watch for that area beginning at 7 AM EST Wednesday and
lasting until snow is forecast to taper off Thursday afternoon.
This Watch may be upgraded to either an advisory or warning in a
future forecast package depending on how additional guidance
impacts our confidence in accumulations.

Beyond the precipitation, tight surface gradients will foster
gusty winds between 30-40mph in the afternoon in the lower
elevations, with 35-45 mph gusts possible in the ridges and even
peak gusts as high as 55 mph possible in the highest ridges of
eastern Tucker County, WV.

Rapid movement of the surface low and upper trough over the New
England region Thursday will bring colder temperatures under
northwest flow and a dry day for most. Snow showers may linger
north of I-80 where lake-enhancement could allow localized
accumulations of up to an inch or so to continue, as well as in
the ridges where weak upslope forcing will support additional
light accumulations.

&&

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

- Unsettled pattern continues through the weekend
- Lake effect & terrain driven snow Friday with another system
  over the weekend
- Temperatures remain well below average
-------------------------------------------------------------------

The unsettled pattern continues to close out the week and into next
weekend as mid-level troughing continues to plague the ECONUS.
A weak shortwave embedded within the broader trough brings
another round of snow to the WV ridges while lake-effect snow
showers continue north of I-80. Eventually, the upper low over
New England advances eastward over the Atlantic as another upper
low dives from northern Canada towards the upper Great Lakes.
This allows additional shots of cold air to filter in, albeit
with both timing and depth differences evident among global
models.

Confidence is increasing in a several day period where we have
high temperatures some 15-20 degrees below average in the cP
airmass through the weekend with highs in the 20s and lows in
the teens or single digits. Cold air being entrenched across
the region means any additional disturbances are likely to
produce snow as the prevailing precip type areawide. While the
overall pattern appears messy and ensembles are clearly
struggling to agree on timing and intensity of any given wave,
confidence is increase in at least one more shot at snowfall
over the weekend before long term guidance finally has the
eastern Canadian longwave trough breaking down. Stay tuned for
more details as we get closer and confidence increases.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
KEY MESSAGES:

- VFR for most of the TAF period.
- Restrictions in snow at FKL and DUJ Tuesday afternoon.
- Increasing S-SW wind Tuesday into the overnight period.
-------------------------------------------------------------------

High pressure will maintain VFR for most airports through
Tuesday morning. The exception will be for LBE and MGW, where a
period of MVFR stratocu cigs are expected early this morning as
cloud cover moves north with a backing wind.

Increasing mid level cigs are expected Tuesday as a warm front
approaches. The best lift and moisture for snow is progged
across areas north of I-80, where FKL and DUJ will likely see a
period of MVFR vsbys in light snow this evening. An increasing
pressure gradient in the vicinity of the front should also
result in increase S-SW wind, with gusts around 20 kt by late
morning through the afternoon. This will persist into the
overnight hours.

By early Wednesday morning, wind speed and gusts will freshen
with the approach of the surface low and cold front. Snow and
rain will accompany this system bringing a high probability for
MVFR ceilings during the day Wednesday.


Outlook...
Restrictions and scattered snow showers are expected Thursday
and Friday with a crossing upper trough, and again Saturday with
approaching low pressure.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory from 1 AM to 10 PM EST Wednesday for
     PAZ007>009-015-016.
OH...None.
WV...Winter Storm Watch from Wednesday morning through Thursday
     afternoon for WVZ514.

&&

$$

SYNOPSIS...Cermak
NEAR TERM...Cermak
SHORT TERM...Cermak
LONG TERM...Cermak
AVIATION...WM/Lupo