000
FXUS61 KCTP 251932
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
332 PM EDT Sun Oct 25 2020

.SYNOPSIS...
A weak area of low pressure will track up the east coast through
tonight. Behind this system, a weakening cold front will push
in from the Great Lakes Monday, then stall out south of the
state. High pressure is likely to briefly build into
Pennsylvania Wednesday, then the remnants of Zeta are likely to
track just south of the state next Thursday.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Afternoon satellite/radar composite shows steadiest light
rainfall occurring over coastal MD/DE southwards to eastern VA.
Very light rain and drizzle covers much of the southern third of
central PA. Cool, dry and stable boundary layer air lies to the
north, with air temperatures in the mid to upper 40s and
dewpoints in the lower to middle 30s. Deep layer moisture conts
to slowly increase from south to north throughout the day, with
0.75" PW contour shifting to the I-80 corridor late this
afternoon. By that time, best forcing/UVM focused from the Ridge
and Valley Region and Lower Susq for highest POPs there into
tonight. Best forcing passes east of the region by later tonight,
but lingering very light rain or drizzle appear likely overnight
given the southeast flow and model soundings that are nearly
saturated from the surface to 700mb. Highest POPs overnight are
placed across the northern mountains, where orographic forcing
should translate to measurable rain in most spots.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
Morning light rain or drizzle gives way to some improvement
Monday afternoon , as boundary layer flow shifts to the south
ahead of approaching cold/occluded front. The southern counties
stand the best chance of breaking into the warm sector with
brightening skies and temperatures rising into the 60s.
Elsewhere, the prospects of any clearing appear dim across the
northern mountains based on model soundings.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
As expected, the first area of showers today mainly south and
east of our area. Not much of these will be left in our area
by late Monday. Much of the time from later Monday into Tuesday
will be mainly dry. Some showers at times during this period, as
a frontal system sags south of the area later Tuesday.

The best day for dry conditions will be Wednesday. A series
of fronts, a cutoff low from the southwestern states, and the
remains of Zeta track toward the area on Thursday into Friday.
At this time, expect most if not all the heavier rain to track
south of our area, similar to last tropical system that track
just to our south.

Colder air will work into the area on Friday. It is possible
that some mixed precipitation could mix across the far north for
a brief time, but the moisture will be pulling away, as the
colder air moves in. 850 mb temperatures surge above zero by mid
week, so will have to cool back down.

A large high will bring dry and colder weather behind the
weather system Friday. This high is abnormally large and cold,
will cover much of the lower 48 states for a brief time, before
the westerlies lift quickly back to the north. The airmass is
very cold for late October, mainly records are expected to fall
across the west early this week. Minus 20 air at 850 mb forecast
west of Hudson Bay later this week.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
MVFR returns north this afternoon and remains through tonight.
MVFR cigs and a chance of showers impact JST and AOO this
afternoon into tonight. MVFR cigs will hold off until late
afternoon or early evening in the lower Susq, along with a
chance of showers. Farther north, VFR conditions will prevail
until about 01-03z Mon before trending lower. IFR conditions
appear possible areawide toward the end of the TAF period with
reduced cigs.

Outlook...

Sun night-Tue...Restrictions likely in lower clouds and and
periodic light rain.

Wed...Mostly VFR.

Thu...More wet weather expected with MVFR and IFR conditions
possible.

Friday...MVFR and IFR conditions expected with showers. Windy.
Improving conditions late, as showers move out of the area.

&&

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

&&

$$
SYNOPSIS...DeVoir/Fitzgerald
NEAR TERM...DeVoir/Fitzgerald
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...Martin
AVIATION...DeVoir/Martin