Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 230359
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1059 PM EST Wed Jan 22 2020

.SYNOPSIS...
Dry weather and milder temperatures will continue through late
week. Another bout of winter weather will impact parts of
central Pennsylvania for the second weekend in a row.

&&

.NEAR TERM /THROUGH THURSDAY/...
High pressure along the Mid Atlantic coast will ensure fair
weather and light wind tonight and Thursday across central Pa.
Warm advection aloft in advance of deepening trough over the
Miss Valley is already resulting in cirrus across Pa and model
rh profiles indicate the high clouds will thicken by Thursday
PM.

Mostly clear skies and a calm wind will allow temperatures to
fall steadily tonight, with readings by dawn likely ranging
from the upper single digits in the coldest valleys of the
north, to around 20F in Harrisburg/Lancaster. NBM max temps
Thursday range from the upper 30s to low 40s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
*Recent guidance is tracking upper low further north, thus have
reduced weekend snow amounts closer to WPC guidance.

POPs remain high Friday PM into Saturday AM associated with the
passage of a strong upper level trough and occluded/triple
point sfc low track across the Mid Atlantic region into the
Northeast states.

Expect increasing clouds Friday morning with no precipitation.
Latest guidance indicates precip will overspread the region
during the PM hours, with boundary layer temps warm enough for
rain in all parts of the forecast area.

However, layer cooling associated with increasing uvvel, and
evap cooling as the precip falls into the dry LLVl air may
result in precip changing to wet snow across parts of north
central Pa, especially over the higher terrain.

Again, we will be messaging the point that the initially warm
boundary layer and periods of strong, dynamic forcing will lead
to an elevation dependent (almost spring-like or late-season)
snowfall across north-central PA with notably lower chances for
accumulating snow across the rest of central Pa.

Most likely snow accums by late Sat night are in the 1-3 inch
range over the northern mountains with nothing across the
southern counties.

The threat for ice appears minimal, but a bit of fzra can`t be
ruled out over the high terrain of northern Pa Friday night or
early Sat morning based on latest guidance.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As the surface low with the storm system pulls away to the
northeast, the associated upper low moves across Central PA
Saturday night. Northwest cyclonic flow on the back side will
continue showers through central PA with highest POPs northwest
and lowest POPs over Lower Susq. Temperatures will be cold
enough Sunday for snow showers most areas. Mix rain and snow
showers possible in the central and lower Susq valley. Expect
lake and mountain upslope enhanced snow showers to continue
thru Sunday night. Behind this system cloudiness will linger as
there continues to be weak flow and troughiness through
Tuesday. Finally on Wednesday a strong upper level ridge builds
in and surface high pressure ahead of the next weather system
developing over the middle Mississippi Valley. This will pump
in some milder air into central PA and bring the next batch of
weather late next week.

&&

.AVIATION /04Z THURSDAY THROUGH MONDAY/...
Surface high pressure and upper ridge slide over PA on Wed,
bringing sunny skies, light winds and VFR conditions.

High clouds will overspread PA late Wednesday night into
Thursday morning, but VFR conditions will persist through the
day.

.Outlook...

Fri...Restrictions perhaps developing during the afternoon, with
the potential for rain, fog, and lower ceilings.

Fri night and Sat...Restrictions are likely to continue, with
the potential for rain to mix with, or change to snow for a
time.

Sun...Restrictions are probable at KBFD and KJST in lower
clouds and snow showers. Improvement back to VFR is the most
likely scenario elsewhere.

&&

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

&&

$$
SYNOPSIS...Steinbugl
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald/Steinbugl
LONG TERM...Watson/Fitzgerald
AVIATION...Watson



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