822
FXUS61 KCTP 181137
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
637 AM EST Tue Nov 18 2025

.SYNOPSIS...
* Rain arrives later today and mixes with elevation-driven, wet
  snow this evening through tonight near & north of I-80
* Mainly dry Wednesday and Thursday; trending milder with some
  rain likely to end the week
* Seasonable and mainly dry weekend before Thanksgiving

&&

.NEAR TERM /THROUGH TONIGHT/...
Quiet start today under the influence of high pressure migrating
eastward across the central Appalachians toward the NC/VA coast.
Some locations in CPA will wake up to temperatures in the mid
to upper teens particularly over the southwestern portion of the
CWA where skies are clear and winds are light.

A fast moving low pressure system streaking eastward from the
Ohio Valley to the Delmarva will bring rain and light snow to
CPA later today through the overnight hours. Hires guidance
shows the steadier precip occurring this evening through
tonight, however the warm advection regime may speed up the
onset. Dry air near the sfc (10-20 degree Td depressions)
should offset the quicker advance/arrival of the WAA precip.

Tight to marginally cold 850mb thermal gradient combined with
elevation and wet bulb effects suggest some mixed/wintry precip
is likely this evening through tonight into early Wednesday
(predawn) morning. HREF data is bullish for freezing rain on
the ridgetops across the Laurel Highlands and southern
Alleghenies particularly Cambria/Blair county border. Icy spots
and slick roads are possible, but overall impact may be limited
given marginal road/air temps. Meanwhile, there is a better
signal for a slushy, minor (<1"), elevation-driven snow accum
particularly over east-central PA near/along the I80 to US220
corridors in the 06-12Z window. Snow accum is most likely on
non-paved and elevated surfaces with minimum temps hovering
near to slightly above the freezing mark. Precip should
end/shift to the east by 7AM/12Z Wednesday.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
High pressure provides mainly dry weather through midweek;
however this period looks rather cloudy especially on Thursday.
Fcst daytime max temps hold steady in the 40-50F range with the
largest 24hr deltas on the order of +5-10F coming Thursday
night (low temps 35-45F or +10-15F above mid Nov. climo).

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Split stream flow and weak frontal system offers the best
chance of rain on Friday to end the week. Latest model and
ensemble trends favor a drying trend through the weekend. Timing
differences and uncertainty both increase with the the next
northern stream wave early next week. Friday looks like the
mildest day with near to slightly above normal temps fcst into
the start of Thanksgiving week.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A stripe of fairly high-based (VFR) and shallow lake effect
strato clouds (with a multi-glake upstream connection) will be
exiting our NE zones over the next few hours through 13-14Z.

A narrow north/south ridge of sfc high pressure and deep dry
air aloft was over Central PA at 1130Z. This will bring
continued widespread VFR with mainly clear skies across the
Central Mtns and Lower Susq Valley, followed by a quickly
increasing mid level cloud deck late this morning through the
mid afternoon hours (from west to east across the state).

The timing of the clearing and increasing clouds will maximize
radiational cooling of the near surface layer, allowing for the
onset of precip to be a cold, light rain or mixed precip
(rain/wet snow) as the level of the wet bulb 0C dips to just
several hundred feet AGL, as is topped by a few to several KFT
layer of wet bulb temps between zero and 1C. The cold air could
be deep enough from near KSEG and KIPT...NE to support a several
hour period of wet snow and relatively lower VSBYS there
later tonight.

Conditions will gradually dip to MVFR during the mid to late
afternoon across the Western Mtns and during the early to mid
evening from the Susq Valley...east.

MVFR to IFR CIGS and vsbys will follow for later tonight and
persist through much of Wed as shallow/moist cool air remains
with very light wind in the lowest 3-4 kft AGL - leading to
widespread, shallow and non-precipitating stratus.

Outlook...

Wed...AM showers southeast, restrictions likely from southeast
flow/low clouds.

Thu...Dry, restrictions likely in low clouds.

Fri-Sat...Widespread rain expected.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl/Colbert
SHORT TERM...Steinbugl/Colbert
LONG TERM...Steinbugl/Colbert
AVIATION...Lambert