Scientific Forecaster Discussion
fxus61 kctp 120231
Area forecast discussion
National Weather Service State College PA
931 PM EST Mon Nov 11 2019
low pressure over western PA will drag a cold front through
overnight. A deep upper level trough will swing through the
area Tuesday into Wednesday. This will bring a short-lived but
very cold air mass into the state for Tuesday and Wednesday.
Look for a warming trend on Thursday and Friday under sunny
Near term /until 8 am Tuesday morning/...
made a small change adding Sullivan co into the advy as the
preponderance of near-term guidance runs a slug of intense
precip (0.25-0.35") over Tioga-Sullivan counties from 06-09z,
barely nipping Lycoming co. Temps at the sfc are below freezing
over half of the County, and they could get some ice at first,
and then, after the precip intensifies, go to all snow. Also
made tweaks to the next few hours of winds/gusts as the front
has been making gusts into the M-u20s and dropping the temps in
and around Pittsburgh 10-14f in less than an hour. Low center is
likely right over or barely to the S of kduj as the pressure is
low now over Allegheny co PA, moving toward figure/ipt right in
line with latest hrrr/rap runs. The precip has barely brushed
the nrn tier counties, but will finally break across the New York
border in the next 2-3 hours. However, the longer it waits, it
should result in slightly lower snow totals. But, they are
already pretty low. Rain will probably push across much of the
County Warning Area at or just behind the cold front which lies right along the
Ohio River and is going to pick up speed and head directly east.
Overall changes were minor with this update. Mainly timing
tweaks, and a little delay on the temp drop across the southern
half of the area. Other than The Laurels, the rest of the srn
half of the area will barely see any snow falling from the sky.
Just a patch here or there may have a trace on the ground in
quiet rest of the afternoon with mild temperatures and precip
remaining west of the County Warning Area. This will change quickly this evening
as band of rain drops into northwest zones. Precip will quickly change
to snow across advisory area which is much closer to colder
air. In the transition there will be a brief period of freezing
precipitation. Elsewhere, precip will sag south and east this
evening and overnight, with thermal profiles well above
Across the New York state border quantitative precipitation forecast will be higher /around a third of an
inch/ which supports the current advisory. Elsewhere rain
showers will be light in this low qpf event, and by the time the
colder air arrives the precipitation will essentially be over
before the freezing air aloft arrives. Surface temperatures
will drop rapidly behind the front, with the freezing
temperatures reaching State College by sunrise tomorrow.
Short term /8 am Tuesday morning through Tuesday night/...
northwest flow develops behind the cold front tomorrow which
will produce scattered snow showers in the usual locations
across the northern mountains and Laurel Highlands. Elsewhere
look for a cold and blustery day with temperatures moving
little perhaps even falling during the afternoon.
Expect diminishing lake effect snow showers Tuesday night, as
the upper trough passes east of the state and inversion heights
fall. Look for the coldest temperatures of the autumn by
Wednesday morning in the single digit and teens across a large
part of the area. Of course the areas which receive the fresh
snow will be the coldest.
Long term /Wednesday through Monday/...
no large changes to this part of the package.
Lake effect snow showers will linger into the northwest mountains
and Laurel Highlands into Wednesday morning, perhaps early aft.
This based on how cold the airmass is and the lakes still being
quite warm. Upper level heights come up, but the 2 factors listed
above are big factors for this time of year.
Went back and fourth on Thursday, but ended going back to being
dry after looking at some new data and making a few edits on the
Next cold front moves in on Friday, but trend is further North.
Heights stay much higher, thus nothing more than maybe a few
snow showers across the north.
Saturday and Sunday look dry.
Monday is largely the superblend. Have some light rain across
the southeast, but amounts will be light if any. Main issue will
be at some point moisture working back to the north off the
ocean, above any remaining cold air.
Overall hints of a pattern change, with more active weather
along or just off the southeast coast.
Aviation /03z Tuesday through Saturday/...
00z update... very changeable conditions overnight across
As colder air seeps in from the NW, rain later this evening will
gradually change over to at least a brief period of snow in the
pre-dawn hours at kipt, kaoo, kunv, and kjst.
At kbfd, colder air is already in place, and a brief wintry mix
later this evening, will go over to snow overnight.
For kmdt and klns, VFR and mild conditions most of the night,
will give way to rain and lowering conditions towards daybreak.
On Tuesday, it will be blustery and much colder, but drier air
will also push in, with conditions improving to VFR across most
of the region. Scattered snow showers in the afternoon could
produce brief restrictions, most likely at kbfd and kjst.
Surface winds should gust 25-30 kt from the northwest.
Wed...scattered snow showers with brief restrictions at kbfd,
Fri...perhaps a snow shower and brief restrictions at kbfd, but
otherwise mostly VFR.
Winter Weather Advisory until 7 am EST Tuesday for paz004>006-