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000
FXUS61 KCTP 050431
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1131 PM EST Mon Dec 4 2023

.SYNOPSIS...
Upper level troughing is expected over the region through the
middle of this week, with a pair of weak Alberta Clippers
passing mainly south of Pennsylvania. Upper level ridging
should build over Pennsylvania late in the week, with low
pressure likely tracking west of the state late next weekend.

&&

.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
Light snow showers/flurries continue this evening across the N
Mtns associated with low convergence/instability in the
vicinity of a weak surface trough. This feature is progged to
wash out overnight and inversion heights will fall, as ridging
builds in from the west. Therefore, expect lingering snow
showers/flurries to diminish overnight, with nothing more than a
dusting on some of the higher hilltops of the NW Mtns.

Low level moisture trapped beneath a subsidence inversion should
result in mainly cloudy skies overnight across the W Mtns, with
downsloping flow yielding partly cloudy skies across the Susq
Valley. See no reason to deviate significantly from NBM min
temps, which are fairly uniform in the lower 30s.

&&

.SHORT TERM /7 AM TUESDAY MORNING THROUGH THURSDAY/...
All eyes will turn to an Alberta Clipper that will be
approaching form the Midwest on Tuesday. This moisture-starved
system is expected to be weakening as it passes to our south.
However, this southerly track is favorable for producing
accumulating snowfall across the Laurel Highlands. Expect light
snow (possibly mixed with rain at lower elevations) to push in
from the west Tuesday aftn/eve and continue into Tuesday night.

Latest ensemble qpf supports around an inch of snow across the
Laurel Highlands late Tuesday into Tuesday night, with up to 2-3
where orographic enhancement is maximized on Laurel Ridge. Lake effect
snow showers associated with a colder NNW flow behind the
clipper could generate up to an inch of snow over the snowbelt
of NW Warren County. Elsewhere, any light snow/flurries should
produce nothing more than a dusting over most of Central PA.
Across the Lower Susq Valley, model soundings indicate any very
light precip could fall as either snow or rain, but surface
temps should remain too warm for even a dusting.

The weakening clipper should have passed south of PA by early
Wednesday. However, passage of a deepening upper level trough
could be accompanied by additional snow showers, primarily over
the Laurel Highland, where an upsloping NW flow and nearly a
saturated sfc-700mb layer in the models supports a good chance
of lingering AM snow showers. Wednesday will likely be the
coldest day of next week, with rising heights expected thereafter.
Fair and chilly conditions are expected Wed night, as ridging
builds in.

Warm advection preceding a warm front lifting through the Grt
Lks could potentially produce a brief period of light snow
across mainly Northern PA Thursday. Despite warming aloft,
a good deal of cloudiness should hold temps to near or a bit
below seasonal normals Thursday, with highs ranging from the
mid 30s to low 40s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Medium range guidance supports fair and increasingly mild
conditions late this week, as upper level ridging builds along
the east coast. The bulk of guidance tracks a deepening surface
low west of PA late next weekend. Without a blocking high to
the northeast of PA, expect well above normal temps to continue
until the arrival of a trailing cold front Sunday PM or Monday
AM.

A deep plume of GOMEX moisture and strong upper level divergence
ahead of an upstream trough should produce a period of moderate
to heavy rain ahead of the front Sunday. Latest ensemble plumes
indicate most likely rainfall will fall between 0.5 and 1.5
inches. Strong/gusty southerly winds are possible if the region
can break into the warm sector Sunday PM. However, climatology
suggests the strongest winds will come in the cold advection
regime behind the cold front Sunday night into Monday. Latest
ECENS plumes indicate a possibility of wind gusts in excess of
40kts during this time frame. A return to cooler weather appears
likely Monday, as upper level trough shifts into the region,
accompanied by lingering orographic rain/snow showers over the W
Mtns.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
A weak cold front sagging down from the north will bring a few
snow showers from time to time across the north. From 06z Tue
through the morning, IFR cigs are possible at BFD and JST, but
marginal moisture is limiting confidence to 50-80%, and it is
possible that these sites bottom out at low end MVFR. Elsewhere,
MVFR to VFR conds are expected to persist through Tuesday.

Lower cigs will begin to work in from the west during the late
afternoon and evening hours Tuesday, along with snow showers, mixed
with rain in the east. Although most snow will be light, a
coating to an inch of accum is poss by the time precip ends Wed,
mainly in the higher terrain of the Laurels, where locally 2+
inches can`t be ruled out.

Outlook...

Wed...Light rain/snow with sub-VFR likely AM, improvements PM.

Thu...Chance of snow showers N/W.

Fri...Mainly VFR.

Sat...VFR early. Showers late.

&&

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

&&

$$

SYNOPSIS...Fitzgerald
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald/Evanego
LONG TERM...Fitzgerald
AVIATION...Gartner/Colbert