Area Forecast Discussion Issued by NWS State College, PA
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000
FXUS61 KCTP 162132
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
532 PM EDT Sat Mar 16 2024
.SYNOPSIS...
Unseasonably mild temperatures kicked off the weekend, but will
gradually drop to below normal for the start of the upcoming
week as a cold front pushes southeast across the state late
tonight and early Sunday.
The cold air will persist into the midweek period accompanied
by a several bouts of snow showers over the Alleghenies and
Laurel Highlands. Temperatures will warm up again during the
latter half of the week ahead.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Surface ridging over Central PA combine with moderately deep
vertical mixing up to around 5 KFT AGL has scattered out the
earlier bkn-ovc stratocu deck across the Western Alleghenies
with temps rebounding to the mid and upper 40s, while abundant
sunshine and mild temps in the mid to upper 50s prevailed over
the Central Ridge and Valley and Susquehanna Region.
Little change is expected through dusk.
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.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
The left exit region of a 125 kT jet max and associated
positive DPVA will accompany the passage of a cold front into
the CWA tonight likely supporting a line of rain showers this
evening. The rain will press from NW to SE thru the night, and
break up across the Central and SE zones as the UVVEL
associated with the aforementioned favorable exit region of the
jet max races off to the east, leaving the region in broad deep
layer subsidence beneath the left entrance region of the same
jet core.
Temps dip enough behind the front (and the DGZ descends into the
upper part of the expanding stratocu deck acrs the Western Mtns)
that anything lingering in he wake of it may mix with/turn to
snow showers just as the flow becomes more lake- effect
favorable.
Rainfall will range from 1-2 tenths of an inch across the NW
Mtns to between a few and several tenths of an inch over the
Central Ridge and Valley Region and little or nothing across the
Middle and Lower Susq Valley.
Not much QPF being produced by most models after 12Z
Sunday as a well-defined mid and upper level dry slot expands
across the CWA, with the straight W-E llvl winds keeping
most/all lake effect to our N.
Subsidence also aids in drying things out, but clouds won`t go
away Sun aftn/night. A gradual decrease in llvl temps will put
the 8H temps down to -2C SE to -8C NW by late in the day
Sunday.
DOD/24 hour max temp drop will range from about 5 deg F across
the Lower Susq Valley to nearly 15F cooler across the NW Mtns.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
-Winter weather through the first full day of Spring
-Risk of locally heavy snow showers and snow squalls Sun-Tue
-Coldest stretch of below average temps since mid-January
Despite plenty of signs of early Spring thanks to one of the
warmest winter seasons and first 15 days of March on record,
the first official week of Spring 2024 will begin on the cold
side with frequent snow showers downwind of Lake Erie and over
the Allegheny Plateau. There will also be the potential for
localized snow squalls through early week along with late
season lake enhanced and orographic snow accumulation in the
favored snowbelts and higher terrain.
Several reinforcing shots of cold air will maintain one of the
longest stretches (3-5 days) of below climo temperatures since
mid-January. That speaks to how mild it has been over the last
few months. Ensemble data shows some moderation by late week
with max precip probs shaded toward southeast PA by the weekend.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
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A few flat cu persist over Central PA heading into the early
evening hours, and a southwesterly breeze continues to
occasionally gust 15-25 kts.
Clouds will begin to increase from the northwest this evening,
as a cold front approaches. Rain showers are expected to develop
across the western highlands after sunset and spread
southeastward. Additionally, a several hour period of LLWS is
expected overnight due to a 35-45 kt southwesterly jet passing
overhead a couple thousand feet off the sfc.
The rain showers will tend to dissipate as they progress
southeastward across the remainder of Central PA overnight, and
may not reach the Lower Susq Valley. Low-end MVFR cigs will
develop over the western highlands (BFD, JST) overnight, and
borderline VFR/MVFR cigs should spill into the central mtns
(AOO, UNV, IPT). The Lower Susq Valley (MDT, LNS) should remain
VFR.
On Sunday, the front will pull away from the area with chillier
air arriving on an increasingly blustery northwesterly wind.
Lingering MVFR cigs and perhaps a few -SHRASN are expected
across the western highlands, with VFR conds expected
elsewhere.
Outlook...
Sun night-Thurs...Periodic snow showers and reductions,
primarily across N/W PA. This will be enhanced by reinforcing
shots of chilly air and gusty W/NW winds.-- End Changed Discussion --
&&
.CLIMATE...
Astronomical Spring (vernal equinox) begins on Tuesday March 19
at 11:06 PM EDT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Steinbugl
AVIATION...Lambert/Evanego
CLIMATE...Steinbugl