Area Forecast Discussion
Issued by NWS State College, PA

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102
FXUS61 KCTP 201930
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
230 PM EST Fri Jan 20 2017

.SYNOPSIS...
Relatively mild but cloudy and unsettled conditions will
persist through the weekend before cooler air makes a return
next week.

A complex storm system is expected to move off the Mid Atlantic
coast Monday and Tuesday and bring rain and perhaps a return of
wintry weather. Much colder temperatures will arrive at the end
of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Steady rain is pretty much over as the main band of rain slides
to the northeast. Some light showers will linger in the nrn
half of the area this evening under the short wave trough as it
finishes moving to the north/east. Warm air will try to work
down into the valleys this evening. Some additional warming is
expected - esp in the east. The temps will not fall much or
even rise overnight. A few breaks in the lower clouds are
working into the SW at 2 pm, but any breaks should be short-
lived. The clouds will hold on and the light/nil wind and rising
dewpoints/llvl moisture will allow for fog and patchy drizzle
overnight. Some of the worst fog may in the SE.

&&

.SHORT TERM /SATURDAY/...
Some fog and drizzle will linger in the morning, and even into
the afternoon on the ridges. Few if any breaks in the clouds are
expected outside the far lower Susq as the lowest 3kft remain
nearly saturated. Maxes are a tough call with lots of cloud
cover, but an 8-12F rise is feasible. Will run with maxes just a
hair under MOS blend. The central counties will probably top out
in the m-u40s, but most other places will. 60F is possible, but
not likely, in the Laurels and Warren Co.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
The upper ridge is forecast to re-establish itself over the
eastern U.S. early in the period, as a very complex storm
system gathers over the southern Rockies by Saturday evening.
This southern stream low is tracked through the southern states
before turning northeast over the eastern US early next week.
Meanwhile the models build high pressure over eastern Canada and
gradually ooze colder air south into the NERN US.

By late Monday into Tuesday morning, the parent upper low is
made to track into the Mid Atlantic states. The deterministic
GFS has the southernmost track, through eastern NC then up just
off the coast. The GEFS has a slightly more northern track
through VA.

The ECMWF and its ensemble partner are more north taking the
storm up through eastern PA. The ECMWF tracks its sub 990mb
surface low through the Del Marva up along the NJ coast is what
we look for as a "sweet spot" for snowstorms locally.
Temperatures are marginally cold so it`s still questionable what
the precip type will be. But it`s the most interesting pattern
we have seen this winter for the snow-birds among us.

After our early week storm system, the eastern ridge is made to
make a rapid rebound, even if for just a short time around
midweek. A fast moving shortwave quickly chews the top off the
ridge we are made to evolve into a cyclonic westerly flow by
week`s end. It will turn cooler, but not especially so as there
really is no truly cold air over North America at the current
time.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
The steady rain has cleared all but KIPT and KBFD. However, the
light southerly wind and increasing dewpoints will lower the
cloud deck in most places after the constant rain ends. The only
clearing might be in the SE, but the L/IFR clouds, fog, and dz
look to be rather widespread for the night.

Some improvement should occur on Saturday in the SE with meager
mixing, but the wind will still be very light. The poor flying
conditions may break for just a short time Sat night and early
Sunday. The next storm will be working up over the MS and TN
valleys over the weekend and start to throw a surge of moisture
north into the Mid-Atlantic. Some rain is expected to move in
later Sunday, mainly across the south. Looks like Monday and
Tuesday will be wet days. Snow is possible in the higher
elevation sites Monday.

Outlook...

Sun...IFR/MVFR CIGs likely. Rain advances fm S-N.

Mon...Rain/low CIGs likely with snow possible at the higher
elevation terminals.

Tue...AM rain/snow and low CIGs possible. PM improvement.

Wed...Rain/snow poss NW late.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...La Corte
AVIATION...Dangelo



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