Area Forecast Discussion Issued by NWS State College, PA
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000
FXUS61 KCTP 170750
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
350 AM EDT Sun Mar 17 2024
.SYNOPSIS...
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A cold front will drop south to the MD border by mid-morning.
Much colder temperatures than recent days will persist into the
midweek period accompanied by a several bouts of snow showers
over the Alleghenies and Laurel Highlands. Temperatures will
moderate to near normal by next weekend.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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The front is just about half-way thru the state, knocking on
the doorstep of the office at 03Z. It is passing right now (03Z)
as we can hear the wind picking up and the flag rippling out
the window. Wind is gusting pretty regularly into the 30-35KT
range as the front passes, and even close to 30KT before it
arrives. The good moisture influx will be lost very soon. Many
places to the SE of State College may not get wet, or just have
some sprinkles. Snow is falling at BFD and other parts of the
nrn mtns, but is not sticking to the roads with road sfc temps
39-40F along Rte 6. The air temp has even recovered a deg or two
as the snow became lighter. However, the falling snow is
visible on webcams. Do not expect anything more than a slushy
coating on the grass/colder sfcs by sunrise.
Temps should rise a little, but will be battling the strong
CAA.The CAA will drop the 8H temps into negative territory for
all the CWA by the end of the day. 8H temp at BFD may be -7C by
sunset. We`ve got more than 12hrs of sunlight already (thanks to
the earth`s curvature: SR at BFD is 722 AM EDT, and SS is 724
PM EDT. So, it is going to make it more difficult to keep temps
from rising during the day moving forward. Maxes will be around
40 N and M-U50s in the white rose and red rose cities.
Multiple shots of PVA will be conducive to convection and
additional SHSN/RA across the higher elevs of the N and SHRA in
the valleys thru the rest of the day. Will introduce some likely
PoPs for a time along and N of I-80 and W of IPT in the aftn.-- End Changed Discussion --
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.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
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After the wave that make a few SHRA/SN in the aftn, the flow
will generate lake effect SHSN for the next 36+ hrs. The wrly
flow will also make some upslope snow in the Laurels, but not
much, with the bulk of the moisture along and N of Rte 6. Some
meager accums are expected for Warren/McKean Cos. Through the
long haul of 48hrs of snow, those NWrn locations may get 4-6" of
snow. At this point, it`s just too slow of an accumulation to
fret over an advy. The ground temps and daytime temps will be
such that the accums will also be more trouble overnights than
during the daylight.
A positively-tilted longwave trough will swing overhead on
Monday, and yield some instability. But, moisture will be
lacking and little sfc frontogenesis/organization is seen on
Monday. Better instability looks like it will occur on Tuesday
as a Clipper low moves across the CWA. If the sfc low goes
across NY or our nrn tier, that could set up a nice cold-frontal
line. There could still be a squall on Monday, mainly NW, but
SHSQ parameter is poor/low. The wind will be gusting close to
20KT anyway.
Mins tonight will be AOB freezing across almost all the CWA.
That hasn`t happened for a while (beginning of the month). Maxes
Monday should hold in the L30s on the higher elevs, and only get
into the M40s in the far SE.-- End Changed Discussion --
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
-Winter feel through the first full day of Spring
-Risk of locally heavy snow showers and squalls Sun night-Tue
-Longest 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 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. That speaks to how mild it has been over the last
few months. Each cold shot will bring a renewed/enhanced shot of
heavier snow showers. Hires guidance currently shows the most
widespread potential for convective snow showers Sun night - Mon
morning, again Mon night-Tuesday.
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.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
Rain showers have developed over NW PA and are currently
progressing SE. Temperatures have dropped faster than expected
in the far NW and a transition to snow shower has already
occurred for some. 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, and this will also result in
some gusty winds on the back side of the sfc cold front.
The rain shower activity should dissipate over Central PA as it
progresses southeastward overnight, and may not even reach the
Lower Susq Valley. Low-end IFR to MVFR cigs is expected for the
western mountains tonight and the early morning hours.
Borderline VFR/MVFR cigs could spill into the central mtns (AOO,
UNV, IPT). The Lower Susq Valley (MDT, LNS) should remain VFR
through the TAF period.
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 predominantly VFR conds
expected elsewhere. Gusty winds will likely end by 06Z Monday.
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.
&&
.CLIMATE...
Astronomical Spring (vernal equinox) begins on Tuesday March 19
at 11:06 PM EDT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Steinbugl
AVIATION...Evanego/Bowen
CLIMATE...Steinbugl