100
FXUS61 KCTP 121525
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1025 AM EST Wed Feb 12 2025

.SYNOPSIS...
*Midweek wintry mix ends as rain followed by a windy day on
 Thursday with snow showers developing into Thursday night
*Brief break in the stormy pattern for Valentine`s Day then
 another round of mixed/heavy precipitation this weekend
*Turning sharply colder next week as arctic air returns into
 the second half of February

&&

.NEAR TERM /THROUGH TONIGHT/...
Late morning update.

Not much on radar or reported in the obs, so did cut POPS down
some across the north for the next few hours. Area of snow on
the radar showing signs of being on the decrease as well.

Earlier discussion below.

Upper level divergence and broad synoptic ascent within the
right entrance region of 140kt 300mb jet streak is producing
some light snow across southwest and south central PA early this
morning. Hires guidance suggests the light snow will persist and
slowly expand northward as the morning wears on. Previous
thinking was that this light snow could/would be freezing
drizzle, but the latest fcst soundings show sufficiently deep
layer saturation particularly in the lower levels thanks to a
moist east southeast upslope flow. It`s conceivable that
some parts of south central PA could pick up as much as a 0.5"
of snow prior to 18Z/1pm with rates 0.25"/hr or less.

The primary and most impactful wintry precip will arrive later
this afternoon and last into the early overnight hours as
impressive IVT overruns cold high pressure wedging down the east
side of the Allegheny Mtns. The strong WAA regime will translate
into a steady snow/sleet/freezing rain wintry mix ptype transition
before turning to mainly plain rain in most places by daybreak
Thursday as temps rise above the freezing mark.

Blended WPC/NBM Liquid Equivalent QPF is <0.50" through tonight
with corresponding snow/sleet generally ranging from 0.5-2.0"
and 0.01-0.25" respectively. The heaviest snow/sleet is most
likely in the northeastern CWA quadrant toward the Poconos/Coal
Region while max ice accretion >0.10" is focused along the
ridgeline between Somerset/Bedford and Cambria/Blair Counties.
We expanded the winter wx advy a layer of zones into the lower
Susq Valley where a glaze of ice is likely in some spots.
However, the ice impacts should be offset/limited or perhaps
alleviated to a larger extent by the rising temps overnight into
early Thursday morning. Some hires models suggest a wave of
moderate precip (mainly rain) is possible btwn 06-12Z Thu in
advance of the cold/occluded front.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Thursday morning should start off rather balmy with morning to
early day highs. This "warm" start will be followed by a surge
of strong CAA driven to the southeast by an increasingly
blustery NWly post-frontal flow. Deep mixing and +6-8mb/3hr
pressure rises favor strong winds with some potential for advy
level gusts >45 mph.

Tricky temp fcst during the day Thursday with falling temps fcst
from NW to SE during the afternoon. Scattered snow showers will
develop downwind of Lake Erie over the higher terrain Thursday
afternoon and persist through Thursday night. Minor snow accums
are likely in some areas.

All model guidance supports 1035+mb high pressure moving over
CPA on Valentine`s Day. This will bring an end to the snow
shower activity and gusty winds while providing a short break in
the active February pattern before the next round of winter wx
arrives to start the weekend.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
By the weekend, another storm will approach the northeast,
though considerable uncertainty remains. An initial burst of
snow appears likely on Saturday as a weak disturbance moves
through ahead of the main system. The latest EPS mean surface
low track across Southeast PA, along with lack of a blocking
high to the northeast, would point to a mostly rain event.
However, there remains plenty of uncertainty and a slight
southward shift could result in significant snow for parts of
the area. It is worth noting that the deterministic guidance has
shifted slightly southward today and indicated the potential
for snow across the northern tier of Central PA.

Although the specifics of the weekend storm remain uncertain,
there is greater certainty in blustery and cold conditions
arriving late Sunday into Monday, as the strengthening surface
low passes east of PA. Mean EPS 2m temps currently support temps
falling into the single digits Sunday night over the NW Mtns,
along with wind chills well below zero.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
Light snow is falling from UNV southward across central PA as of
15Z Wed, generally bringing vsbys down to IFR or low end MVFR,
except for northern airfields IPT and BFD at VFR. This area of
light snow will likely dissipate by late morning. Then low
pressure approaching from the Miss Valley will spread a batch of
wintry mix and lowering cigs across the entire region through
this evening. Ensemble prob charts support fairly widespread
IFR/LIFR conditions by late Wed evening across Central PA. Low
level wind shear is likely Wed night (mostly after 06z) as winds
at 1500-2000 ft increase to around 50 kts from the SSE.
Stronger wind gusts up to 30-35 kts will mix down to the sfc on
Thursday.

Outlook...

Thu...AM low cigs/rain. PM gusty winds.

Fri...No sig wx expected.

Sat...Rain/snow/low cigs possible, mainly PM.

Sun...AM rain/low cigs likely, snow possible NW Mtns. Becoming
windy toward evening with snow showers W Mtns.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 4 AM EST Thursday for PAZ004-005-
010-011-017-024>028-033>035.
Winter Weather Advisory from 4 PM this afternoon to 4 AM EST
Thursday for PAZ006-012-018-019-037-041-042-045-046-049>053-
058.
Winter Weather Advisory from 4 PM this afternoon to 11 PM EST
this evening for PAZ036-056-057-059-063-064.

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl/Martin
SHORT TERM...Steinbugl
LONG TERM...Fitzgerald/Bauco
AVIATION...Gartner/Colbert