Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 171604
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1204 PM EDT Sun Mar 17 2024

.SYNOPSIS...
A trend toward much below normal temperatures for mid to late
March will occur today into Monday 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 over the Alleghenies
and Laurel Highlands. Temperatures will moderate to near normal
by next weekend.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Colder air, in the wake of the cold frontal passage across the
state overnight and early today, will gradually deepen as we
head through the remainder of today.

There`s quite a strong north to south temp gradient across the
CWA with 700 mb temps ranging from about -8C across the
Southern Tier of PA to between -15C and -17C over the north.
The push of the notably colder air up north will lead to the
upper part of the stratocu falling within the DGZ. This
favorable thermal profile for snow showers will combine with a
few spokes of mid- upper level DPVA (approaching from Northern
Ohio and Southern Lower Michigan), to increase the areal
coverage of rain/snow showers across the northern Mtns of the
state this afternoon.

However, midday temps/dewpoints are such that any snow that
mixes in during the daylight hours shouldn`t stick, especially
on the roads. These showers will slide eastward, and just a
little to the south through this afternoon.

There should be a short break in the precip across the northern
Mtns late this afternoon with another burst of showers in the
early evening. Those may end as some snow that sticks
if the temps get cold enough by the time they dwindle/slide
east.

Temps this afternoon should be steady (north and west), and will
climb just a few more deg F over the southeast, 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: Sunrise 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.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH MONDAY NIGHT/...
The flow will generate lake effect SHSN for the next 36+ hrs.
The wrly direction will also generate 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 48-60hrs 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
the 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.

&&

.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 /16Z SUNDAY THROUGH THURSDAY/...
Low-end VFR to ocnl high end MVFR cigs are expected for the
Northern and Western Mountains this afternoon with ocnl
-SHRASN, while VFR 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 mid to late afternoon as cooling
aloft occur with the approach of a few upper level disturbances.
The Lower Susq Valley (MDT, LNS) should remain VFR.

The overnight-early morning cold frontal passage will be
followed by chillier air being ushered in on an increasingly
blustery northwesterly wind - that will frequently gust between
20 and 25 kts.

Gusty winds will likely end by 06Z Monday.

Outlook...

Tonight-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...Lambert/Dangelo
NEAR TERM...Lambert/Dangelo
SHORT TERM...Dangelo
LONG TERM...Steinbugl
AVIATION...Lambert
CLIMATE...Steinbugl


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