Area Forecast Discussion Issued by NWS State College, PA
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000
FXUS61 KCTP 180019
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
819 PM EDT Sun Mar 17 2024
.SYNOPSIS...
A trend toward much below normal temperatures for mid to late
March started today and the cold air will stick around for much
of the workweek ahead.
This colder air will be accompanied by gusty West-Northwest
winds and several bouts of snow showers, especially over the
Alleghenies and Laurel Highlands where a few to several inches
of total snow accumulation is expected by Wednesday morning.
Temperatures will moderate to near normal by next weekend.
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.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
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Regional radar loop at 00Z shows a dwindling band of snow
showers along a secondary cold front, which lies just north of
I-80. Low level thte fields indicate the front will push through
the southeast part of the forecast area late this evening.
However, dry air and lack of large scale forcing should cause
any lingering snow showers associated with it to fall apart
after sunset. The focus for the rest of the night will be over
the NW Mtns, where falling heights ahead of an approaching upper
trough will likely support additional snow showers late
tonight. Inversion heights will remain fairly low, so
anticipate only minor accumulations of up to an inch over
Warren/Mckean counties.
Cold advection behind the front should result in steadily
falling temps overnight, with min temps by dawn ranging from the
mid 20s over the NW Mtns, to the mid 30s across the Lower Susq
Valley.-- End Changed Discussion --
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.SHORT TERM /7 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
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The upstream mid/upper level trough will drift over the region
late Monday, resulting in a chilly and unsettled Monday.
The combination of falling heights and diurnal heating is
progged to result in steep lower tropospheric lapse rates and
even a bit of cape by afternoon, resulting in scattered snow
showers and even a few heavier squalls over the northwest
counties. Latest CAMS indicate mainly cellular convection, due
to lack of significant shear or a strong front to focus
convection. Progged surface wet bulb temps indicate air temps
could fall several degrees below freezing during any squalls
over the Allegheny Plateau, so can`t rule out locally hazardous
travel in this area during the PM hours. See no reason to
deviate from NBM max temps Monday, which range from the mid 30s
over the higher terrain of the Alleghenies, to the mid 40s over
the Lower Susq Valley.
Large scale subsidence behind the trough should cause any snow
showers to end over the eastern half of the forecast area.
However, a cold west-northwest flow should generate lingering
lake-enhanced, orographic snow showers over the Allegheny
Plateau. Relatively low inversion heights should keep additional
accumuations light (generally less than 1 inch based on model
qpf).-- End Changed Discussion --
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.LONG TERM /TUESDAY THROUGH SUNDAY/...
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-Winter feel through the first full day of Spring
-Longest stretch of below average temps since mid-January
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 midweek 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, with chilly temperatures hanging in through the week.
Latest guidance suggests one last cold shot Thursday,
potentially setting the stage for synoptic wintry mix Thursday
night into Fri morning ahead of the next weather maker. Still
several days out, so there is high uncertainty with the
potential system at the end of the week, and whether warmer air
will make a return for next weekend.-- End Changed Discussion --
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Low-end VFR to ocnl high end MVFR cigs are expected for the
Northern and Western Mountains for the rest of this afternoon
and evening with ocnl -SHRA (mixed with or falling as -SHRA in
the valleys), while VFR category sct- bkn clouds will be found
across the Central and SE part of the PA.
Borderline VFR/MVFR cigs could spill into the Central Mtns
(AOO, UNV, IPT) during the late afternoon/evening hours as
cooling aloft occurs with the approach of a few upper level
disturbances. The Lower Susq Valley (MDT, LNS) should remain
VFR right through tonight and Monday.
West-Northwesterly wind will frequently gust between 20 and 25
MPH late this afternoon/early this evening, before subsiding by
5-10 mph overnight then picking back up to similar speeds and
gusts that we experienced today.
Outlook...
Monday-Thurs...Periodic snow showers and reductions, primarily
across the higher terrain of Northern and Western PA. This will
be enhanced by reinforcing shots of unseasonably cold air and
gusty W/NW winds. West to Northwest wind gusts could peak in
the 35 to 40 mph range on Wednesday.
&&
.CLIMATE...
Astronomical Spring (vernal equinox) begins on Tuesday March 19
at 11:06 PM EDT.
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.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Fitzgerald
SHORT TERM...Lambert/Fitzgerald
LONG TERM...Steinbugl/RXR
AVIATION...Lambert/DeVoir/Bowen
CLIMATE...Steinbugl