Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 10/01/22

Area Forecast Discussion

National Weather Service State College PA

 1116 PM EDT Fri Sep 30 2022

.SYNOPSIS...
High clouds will thicken across the region this afternoon,
but some sun will filter through the clouds.

A 4 to 6 hour period of rain, associated with the remnants of
Hurricane Ian, will spread north across the Commonwealth late
tonight through the mid morning hours Saturday before
transitioning to periods of mainly drizzle late Saturday
morning and afternoon. Another area of heavier showers could
track across western sections of central Pennsylvania late
Saturday afternoon into the evening hours.

Showers and drizzle will continue for late Saturday night
into Sunday.

Relatively light northeast this evening will increase and gust
into the 20 to 30 mph range on Saturday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
7 pm update... The leading edge of the light rain is into
northern MD early this evening, right about on schedule. It
should continue its slow northward trek overnight, reaching the
southern PA counties between 8 and 10 pm, and perhaps
approaching the I-80 corridor during the pre-dawn hours.

Early evening ACARS soundings from KPIT and KMDT still show a
formidable dry layer between about 850 and 500 mb, so this
should cause much of the initial light rain to evaporate before
reaching the surface. However, a similar dry layer at KBWI and
KIAD quickly moistened up in the last few hours, so ultimately
we do expect the rain to come into the Commonwealth by later
this evening.

It will be a damp, cool night for many, with lows by daybreak
ranging from the mid 40s over the northern mountains, to the
lower 50s across south-central PA.

Previous discussion... 1 PM Update... Lowered temps a little
for the afternoon seeing the recent trends with no decrease in
the clouds expected. While the clouds are mostly cirrus with sun
filtering through across the N...it`s still cloudy.

The combination of high pressure from the Great Lakes to the
England States this afternoon, with Ian to the south, will
result in rain overspreading the area from south to north.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
Models have hinted at two areas of heavier rain for days now.
One area with warm advection working northwest early Saturday,
and another along or just west of the mountains late in the day
on Saturday. Minor changes to the POPS and QPF.

Main change was to lower the temperatures on Saturday, and
adjust the winds up some in a few spots, given the airmass
in place, and the pressure gradient.

For Sunday into Monday, the heaviest rain out of the area,
but still mainly cloudy with some showers, especially across
the south on Sunday.

Main change was to lower temperatures on Sunday and even some
on Monday.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
11 pm update... On the large-scale, the pesky late weekend and
early work week upper low near the Mid-Atlantic coast should
finally begin to open and move into the western Atlantic by
mid-week, to temporarily be replaced by flat short-wave ridging
aloft. Thereafter, as upper ridging builds over the western
CONUS and southwestern Canada, a downstream upper trough will
deepen over the Great Lakes and northeastern states from late in
the week into next weekend.

As for the daily sensible weather, Wednesday and early Thursday
look dry and fairly mild, as a warm advective southwesterly flow
develops ahead of an approaching surface cold front. The just
mentioned cold front is progged to cross the Commonwealth by
late Thursday, accompanied by at least scattered showers. The
end of the week through at least next weekend looks to turn
sharply colder at this early vantage point, as a very chilly air
mass drops down from south-central Canada. The combination of
this chilled air moving over the warmer Great Lakes waters, plus
short-wave energy aloft should lead to at least scattered
showers over northwestern PA and the Alleghenies. Farther east
towards the Susquehanna Valley, downsloping should produce
mainly dry weather.

Daily highs in the 60s and 70s Wednesday and Thursday should
drop quite a bit by Friday and Saturday, with highs ranging from
the mid-upper 40s in the northern mountains, to nearing 60 in
the Lower Susquehanna Valley.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
At 03z, VFR conditions were still found areawide beneath
thickening high and mid-level cloudiness. Some very light rain
has begun to reach the ground in the Lower Susq Valley.

Lowering cigs and rain will spread northward overnight. Most
locations south of I-80 should see MVFR cigs/vsbys by daybreak
on Saturday, and far southern PA could be approaching IFR cigs.

Low clouds and periods of rain should continue on Saturday
across southern PA, and the light rain could eventually reach
far northern PA as the day progresses. A northeasterly breeze
of 10-15 kts will develop and occasionally gust a bit higher.

Outlook...

Sun...Periods of rain/low cigs persisting, primarily across
southern and eastern PA.

Mon...Chance of rain showers lingers, primarily across
southeastern PA.

Tue-Wed...VFR conditions return.

&&

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

&&

$$
SYNOPSIS...Martin
NEAR TERM...Jurewicz/Lambert/Dangelo/Martin
SHORT TERM...Martin
LONG TERM...Jurewicz/Fitzgerald/Dangelo/RXR
AVIATION...Evanego