Scientific Forecaster Discussion
fxus61 kctp 191648
Area forecast discussion
National Weather Service State College PA
1148 am EST sun Nov 19 2017
cold and windy conditions are expected through tonight with
lake effect snow accumulation over the northwest alleghenies and
Laurel Highlands. Thanksgiving week looks mainly dry with
temperatures trending milder to above average into Tuesday
before cooling off to near seasonal levels for the rest of the
Near term /through tonight/...
pretty classic Post-frontal early cold season pattern with gusty
northwest flow, lake effect/orographic rain-snow showers and
lots of stratocu. The highest ridges in the Laurel Highlands
picked up a coating-1" of snow early this morning with no snow
reported over the northwest alleghenies. Temperatures ~ 32-34f will
limit accumulation this afternoon but temperatures falling below
freezing this evening and into the 20s overnight should easily
allow snow to stick.
No changes to the winter wx advisory. Will let the Wind Advisory
expire at 12pm. Frequent wind gusts ~ 25-35 mph will continue
into tonight but remain below 40kt criteria. Minimum wind chills
will drop into the teens and 20s into Monday morning.
Short term /Monday/...
Monday looks like the thermal trough lifts away and the lake
effect and clouds lift/end.
Long term /Monday night through Saturday/...
the extended part of the forecast will see the season's first
real lake effect snow event winding down early in the period,
followed by several days of cool but tranquil weather.
Model soundings show the inversion heights falling quickly
Sunday evening through Monday morning, which will begin the
process of shutting off the lake effect machine. Look for
accumulating snow to continue overnight over the normal snowbelt
areas of the northwest and even down into The Laurels-with lesser
amounts. The snows will continue shrinking back closer to the
immediate vicinity of the lakes by Monday morning and by Monday
afternoon there should be little more than a few leftover
flurries as the high builds off to our south and we see the
thermal advection switch from cold to warm.
High pressure will keep conditions dry into Tuesday before a
weakening front sliding by to our north brings the small chance
of a snow shower to northern areas Tuesday night and Wednesday.
Another area of high pressure will build east and keep US mainly
dry at least through the end of the week, before a new frontal
system takes aim at the area.
Aviation /16z Sunday through Thursday/...
expect gusty northwest winds today in the wake of overnight
cold front passage. Lake effect snow showers will affect kbfd
with MVFR to IFR conditions through much of the day. Cigs will
drop into MVFR range from scattered snow/rain showers at kjst,
kaoo, and kunv into this afternoon.
Mon...am shsn/reduced vsbys possible northwest mountains.
Tue-Thu...no sig wx expected.
Wind Advisory until noon EST today for paz006-010>012-017>019-
Winter Weather Advisory until 1 PM EST Monday for paz004-005.