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000
FXUS61 KCTP 201725
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
125 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 today
and Sunday, resulting in cooler and breezy conditions. Frost is
expected in many areas of Central and Northern PA Sunday
morning, and maybe even more likely on Monday morning as high
pressure moves overhead and the sky clears.

&&

.NEAR TERM /THROUGH TONIGHT/...
*** 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 midday
hour with SKC-SCT high-based cu.

Moderately strong low to mid level temp advection will spread
across the region (aimed especially at the Northern Mtns - where
a thickening area of 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 see
increasing, high-based cu and the 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 /SUNDAY/...
The wind picks back up on Sunday. Another weak vort max rolls
overhead in the middle of the day, and could make a few clouds,
but not likely any precip. Did add a 10 PoP for the nrn mtns,
though. Temps should get back into the 50s for just about
everyone which is 5-8F below norms.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Model guidance all supports dry conditions Sunday 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 /18Z SATURDAY THROUGH THURSDAY/...
Expect VFR to prevail at all airfields through 00Z Sunday,
except for some brief dips into MVFR CIGS and perhaps 6SM -shra
from bkn-ovc035 at KBFD.

The main concern will be a gusty WNW (270-310) wind with
sustained 15-20KT speeds and G25-33KT developing for the late
morning and afternoon hours and continuing into the early
evening hours.

NW winds decrease tonight and conditions will be generally VFR
under an increasing 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