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FXUS61 KPBZ 081804
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
104 PM EST Mon Dec 8 2025

.SYNOPSIS...
Active weather pattern through next weekend will bring rounds of
snow, occasionally mixed with rain, as well as fluctuating
temperature and gusty winds. Overall, the seasonably cool
conditions are favored with snowfall accumulations favoring
northwestern Pennsylvania and the higher terrain of West
Virginia.

&&

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

- Snow tapering off for far southern zones
- Seasonably cool temperature continues
---------------------------------------------------------------

Surface high pressure centered over the Great Lakes will
continue to promote dry weather and generally clear conditions
across the region; cold, dry air working in from the NE ensures
temperature remains well below the seasonal average. Weak
shortwave/surface low pressure movement south of the region may
maintain generally light snow over the far southern portions of
the forecast area through this evening before its eastward exit
signals an end.

Overnight low temperature should be on the order of 10 to 15
degrees below the daily average; however, subtle nuances like
wind staying slightly more elevated/mix out of the E or
lingering cirrus (or surging lower stratus from south in warm
advection) may stunt the degree of cooling currently forecasted.

&&

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

- Weak, fast moving trough brings light snow to northwest PA
  Tuesday afternoon
- Stronger low Wednesday features a mix of rain and snow that
  will transition back to all snow Wednesday night
----------------------------------------------------------------

A weak shortwave currently crossing the northern Great Plains
is expected to drop through the eastern Great Lakes by Tuesday
evening. As high pressure slides to the Atlantic Coast in
response to its approach, weak warm advection will lift area
temperature approximately 10 degrees above today`s readings.
Meager moisture profiles and weak jet-ascent will limit this
system`s precipitation shield to along/north of I-80; timing of
the passing wave and weak frontal boundary favors a 2pm onset
and 7pm exit with any lingering precipitation being light and
generally non-accumulating. Thermal profiles favor all snow but
that lack of deeper moisture/strong lift means probabilities of
exceeding 1" of accumulation is low (15-30%).

Rapid transition occurs Tuesday night into Wednesday morning as
a deeper upper trough wave enters the Great Lakes region in the
wake of the prior wave. The Tuesday afternoon front is likely to
quickly stall then lift 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
the early morning hours before spreading areawide by the
afternoon ahead of the upper trough/surface cold front passage.

Precipitation type will be a bit more tricky given the
aforementioned warm advection ahead of the axis, but overall
confidence remains relatively high. Any snowflakes that fall
across eastern OH into southwest PA are likely to change over to
rain within a few hours of onset, preventing accumulations.
Change over, or the occurrence of a rain/snow mix, will be later
in the afternoon for northwest PA and the higher terrain
southeast of Pittsburgh. Until this occurs, accumulating wet
snow is likely and favoring the I-80 corridor during the morning
commute (6-hour totals of 1-2" with locally higher amounts
expected in this period). If confidence increases for potential
roadway impacts or higher accumulations, a Winter Weather
Advisory may be needed covering this period (see more on snow
below). Beyond the precipitation, tight surface gradients will
foster gusty post-frontal wind between 25-35mph in the
afternoon in the lower elevations (nearing Wind Advisory
criteria in eastern Tucker).

Rapid movement of the surface low and upper trough shortwave
towards the New England region will occur Wednesday night into
early Thursday morning. Residual northwest flow, weak vorticity
advection, and strong cold air advection means a change over to
snow showers that receive lake enhancements occurs through the
late afternoon to evening hours Wednesday. For most locations,
that will generally be light on and off snow showers resulting
in less than 1" of total accumulation. Higher confidence exists
for potential headline-worthy accumulations and/or impacts along
the I-80 corridor and higher terrain, but location/duration
of the heaviest snow varies due to subtle differences in
ensemble model synoptic patterns. For eastern Tucker County,
wind may remain elevated such that falling, blowing snow could
create periods of significantly reduced visibilities that
further complicates travel. If confidence in totals or impacts
increases, especially as higher- resolution model data comes
into play, headlines may be needed for those areas (I-80
corridor and higher terrain southeast of Pittsburgh).

&&

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

- Unsettled pattern continues through the weekend
- Lake effect & terrain driven snow Thursday/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.
Indications among ensembles are for a deeper, closed low to
eventually take shape across Ontario and Quebec allowing for cold
air to filter in, albeit with both timing and depth differences.
Confidence is increasing in a several day period where we have high
temperatures some 15-20 degrees below average in the cP airmass
through next weekend and likely the coldest air of the year so far.

Regarding precipitation, those aforementioned timing issues have,
and still are, troubling the NBM PoPs for a good portion of Thursday
and Friday; it continues to advertise chc to even lkly PoPs when, in
reality, a good chunk of that timeframe will likely be dry,
especially in the lowlands with lingering snow contained to the
ridges and lakes in NW flow. What seems more likely at this time is
that we`re between shortwaves late Thursday into Friday, and we`ve
lost enough moisture and forcing in the post-frontal environment to
confine snow to the ridges and I-80 corridor. Some ensemble members
bring in transient high pressure during this timeframe lending
higher confidence to more broad dry conditions. After that, yet
another shortwave crosses the region late Friday and Saturday with
the synoptic pattern favorable for a fast moving clipper system and
another chance for some snowfall accumulation dependent on track and
available moisture. Ensemble low centers largely favor a Canadian
track with this system, though some bleed down a bit farther south,
so will monitor these trends and resultant impacts locally through
the week.

Longer range ensemble members signal that there could be some
breakdown to the troughing pattern by early next week and a trend
back toward normal temperatures, but that remains highly
uncertain with many solutions still in play. NBM MaxT suggests
10-15 degree MaxT spread come early next week ranging from the
teens on the low end to the mid 30s on the high end.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
KEY MESSAGES:

- VFR with cirrus favors through the majority of the TAF
  period.
- Active weather pattern will continue through end of week that
  creates periodic precipitation and restriction chances.
-------------------------------------------------------------------

Surface high pressure settling over the Great Lakes will promote
VFR conditions through the TAF period, with occasional breezy NE
winds through the early afternoon. Upslope convergence overnight in
the wake of upper shortwave movement south of the region will likely
result in scattered to broken below 5kft cigs along the western
slopes of the Laurel Highlands, spreading as far east as HLG and
ZZV. Given hi-res guidance suggesting a 60-80% probability of
this stratus layer coming in below 3kft after 06z at MGW, this
has been added to the TAF with tapering amounts of
probability/inclusion at the rest of the TAF terminals.

Outlook...
A one, two set of systems Tuesday afternoon through Thursday
will continue the active pattern and feature a various mix of
rain/snow depending on rapidly-evolving thermal profiles. Expect
restrictions to become more common place while area wind gusts
increase as well.

The active weather pattern is likely to continue into next
weekend, offering periodic precipitation and restriction
chances.

&&

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

&&

$$

SYNOPSIS...Frazier
NEAR TERM...Frazier
SHORT TERM...Frazier
LONG TERM...MLB
AVIATION...Cermak/Frazier