Area Forecast Discussion
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FXUS61 KCTP 240546
Area Forecast Discussion
National Weather Service State College PA
1246 AM EST Tue Jan 24 2017
A strengthening storm will move east of the NJ coast early
Tuesday. High pressure and unseasonably mild conditions will
briefly return for midweek before a pattern change brings colder
temperatures and lake effect snow to close out the month.
.NEAR TERM /UNTIL 9 AM THIS MORNING/...
Extended the advy for the Laurels due to new model progs of a
continuation of snowfall through the night - and even into the
morning as a deformation band sets up N-S right along the wrn
mtns. While additional accumulations may not be more than an
inch - it will be very wet and heavy stuff. This could lead to
some power outages. Have aligned the end time with the other
group for convenience and speed of issuance sake. May adjust the
end time later - later tonight.
Extremely complex potpourri of precipitation types occurring
from north to south across central PA due to variations in
intensity, elevation and surface temperatures. Periods of light
snow and sleet continue in a ribbon from the central mountains
to the Laurel Highlands. Farther north, dynamic cooling was not
sufficient for a full changeover to sleet and snow...and
freezing rain has been occurring over the Endless Mountain
region and parts of the Middle Susq River Valley.
CAMs indicate a redevelopment of TROWAL/deformation
precipitation across central and north central PA...with
moderate rates being maintained along and north of I80 into the
Winter Storm Warning area. Most snow/sleet accums over the
Laurels and Central Mountains have already taken place, but
additional coatings of snow/sleet and even patchy freezing rain
are likely as migratory bands propagate east to west as the
Upper low tracks nwd along the mid Atlantic coast along with the
sfc low overnight.
All headlines remain in effect...including Laurel Highlands
Advisory which expires at 05z. Will likely need to keep central
Mountains advisory through the overnight due to radar trends and
aforementioned CAM guidance which continues to indicate a
second surge of mid/upper level energy over much central and
eastern PA after midnight. Messy travel continues from the
Laurel Highlands through the central mountains and parts
.SHORT TERM /9 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
Models continue some snow through the daytime in the NE, but
also, to a lesser extent, across the rest of the area. Will
consider extending the advy which is slated to expire at 12z
later based on trends closer to the next update.
Winter storm impacts over North-Central/Northeast PA will come
to an end by Tuesday afternoon as strong surface low continues
to lift northeast along the Mid Atlantic/New England Coast.
Strong WAA pattern quickly follows into mid week with high
pressure ridge axis crossing the area on Wednesday. Maximum
temperatures on Wednesday are fcst to climb well-above normal
for late January.
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A well-advertised pattern change remains on track from the
second half of the week into the weekend, with high confidence
in a long wave trough carving out over the Eastern U.S. This
will result in a prolonged period of seasonably cold
temperatures and lake effect/high-terrain snow showers during
the remainder of the period. Several inches of snow is probable
in the typical locations like the Lake Erie Snowbelt.
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Looks like the old upper lvl low is just northwest of the
office at midnight. While the sfc and upper lvl low along the
coast will become the main storm, the upper lvl low to the
northwest will serve as the pivot point, and the rain and snow
will work back the west for a while early today. Hint of this
is the high ceiling at AOO and the west wind there. Also trends
to the precipitation on the radar.
More info. below.
A storm moving up the Mid Atlantic coast will bring a mixture
of rain and snow to central Pa overnight. Latest GLMP MELD
suggests the higher terrain airfields, including BFD and JST are
likely to experience predominantly IFR/LIFR conditions
overnight with periods of snow, while the rest of central Pa is
likely to experience occasional rain or snow with CIGs teetering
between IFR and MVFR.
Improvement on Tuesday, as storm lifts to the NE and precip
comes to an end. Drying effect of downsloping NW flow will yield
rising CIGs across eastern PA, with VFR conditions likely by
evening at MDT/LNS. At the high terrain airfields of western PA,
upsloping flow will likely yield lingering IFR CIGs at BFD/JST
for most of the day. Bufkit soundings indicate most of central
PA will experience wind gusts of 20-25kts Tuesday.
Wed...Low cigs/rain possible western 1/2. Breezy late.
Thu-Fri...MVFR/IFR in snow showers west. MVFR to VFR east.
Sat...MVFR/IFR in snow showers west. MVFR to VFR east.
Winter Weather Advisory until 7 AM EST this morning for PAZ005-
Winter Storm Warning until 10 AM EST this morning for PAZ006-