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000
FXUS61 KCTP 201848
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
248 PM EDT Sat Apr 20 2024

.SYNOPSIS...
An upper level trough with unseasonably cold air aloft will
swing through eastern Canada and the northeastern states late this
afternoon and Sunday, resulting in cooler and breezy
conditions.

Frost is expected in many areas of Central and Northern PA
Sunday morning, and may be even more likely on Monday morning
as high pressure moves overhead and the sky clears.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
*** Issued a Frost Advisory for the Central RIdge and Valley
 Region and Middle Susq Valley for 06Z-12Z Sunday after blending
 in some of the cooler NBM temps to our current fcst temps.
 Playing this early season frost on the cautious side, since
 we`ve bumped up the start of the official growing season by
 about 10 days across much of the SE half of the CWA and have
 received calls concerned about the frost. That being said, the
 negating factor for potentially more widespread frost is a
 layer of thickening Cirrus/Cirrostratus that will drift across
 much of Southern PA late tonight.

The bulk of the CWA is covered by abundant sunshine this mid
afternoon hour with SKC-SCT high-based cu.

Moderately strong low to mid level temp advection is spreading
across the region (aimed especially at the Northern Mtns -
where fairly thick stratocu and even a few showers are expected
this afternoon).

Dewpoints are mainly in the mid 20s to low 30s across the
region with temps ranging from near 50F across the NW mtns to
the low 60s in the far SE. A minor rise in temps will occur in
the SE valleys, while the NW Mtns will see temps fall back by up
to several Deg F this afternoon.

Across the Central Ridge and Valley Region, we`ll have varying
amounts of high-based cu. Deep vertical mixing up through 7-8
kft AGL will transport wind gusts of 25 to 30 kts to the surface
through 22Z before winds slacken a bit around dusk.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
After a night of lighter wind, northwest winds will increase,
but only moderately and into the teens, later Sunday morning
through the afternoon.

Another weak vort max rolls overhead in the middle of the day,
and could make a few clouds, but not likely any precip.

Will maintain just a 10 PoP for the nrn mtns for what`s likely
to be just a few sprinkles, and not actual measurable rainfall.

Temps should get back into the 50s for just about everyone
which is 5-8F below norms.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Model guidance all supports dry conditions Sunday night through
through Tuesday morning, as high pressure and an associated
low-pwat air mass builds into the area. However, upper level
troughing does support below average temperatures into early
next week.

The combination of light winds, dry air, and mostly clear skies
associated with surface ridging is likely to result in good
chance of frost Sunday night. The greatest risk of frost is
over the northern mountains where the growing season is not
active, but areas in the growing season farther south could
also be affected.

A decent warmup looks likely Tuesday, as high pressure passes
off of the east coast. However, medium range guidance all points
to a chance of showers and a subsequent cool down associated
with a cold front passage Tuesday night into Wed AM. The
moisture return ahead of the front looks unimpressive, but
strong forcing ahead of a potent upper level shortwave suggests
a good chance of rain. Latest plumes support a general 0.2 to
0.4 inch rainfall.

It appears there will be another chance of a frost/freeze Thu
and Fri AM, as Canadian High Pressure builds over the region.
Those with agricultural interests should keep an eye on the
forecast for the end of next week.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Expect VFR to prevail at all airfields through 00Z Monday,
except for some brief dips into MVFR CIGS late this afternoon
and tonight and perhaps 6SM -shra from bkn-ovc035 at KBFD.

The main concern for the rest of the daylight hours will be a
gusty WNW (270-310) wind with sustained 15-20KT speeds and
G25-33KT.

NW winds decrease tonight and conditions will be generally VFR
under an increasing/thickening layer of cirrus. Lingering
BKN025-035 CIGS could occasionally occur at KBFD and VCNTY
overnight.

Outlook...

Sun-Mon...No sig wx expected.

Tue...Slight chance of evening showers/cig reductions NW Mtns.

Wed...Showers move in west-to-east from rain early, continues
throughout the day. TSRA possible SW late PM.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 2 AM to 8 AM EDT Sunday for PAZ019-025>028-
034-035-045-046-049>053-056-057.

&&

$$

SYNOPSIS...Lambert/Dangelo
NEAR TERM...Lambert
SHORT TERM...Lambert/Dangelo
LONG TERM...Fitzgerald/Banghoff
AVIATION...Lambert