Area Forecast Discussion
Issued by NWS State College, PA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCTP 022317
Area Forecast Discussion
National Weather Service State College PA
617 PM EST Fri Dec 2 2016
-- Changed Discussion --A large and deep storm system will move slowly across northern
New England through Saturday, keeping a prolonged period of cool
northwest flow and a gusty wind over the local area. A ridge of
high pressure will slide east across the commonwealth for Saturday
night and Sunday accompanied by fair dry weather and light wind. A
weak frontal boundary will then cross the region Sunday night and
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.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --Cold cyclonic flow over the Great Lakes will keep a blanket of
strato-cu clouds over practically all of the CWA overnight.
Chances for lake enhanced snow will increase as the low level flow
becomes more favorable to steer the snow showers into the northern
mountains. The HRRR shows this support for increased banding by
midnight, and even hints that narrow bands of snow showers could
reach into central areas.
A light accum of a coating to one inch should occur across the
Laurel Highlands overnight, while the NW mtns (specifically Warren
and Mckean counties see snowfall totals of 1-2 inches with locally
higher amounts possible north and west of the city of Warren.
Additional light snowfall Saturday morning from LES showers could
bring 18-24 hour totals to 3 or 4 inches throughout the typical
snowbelt of NW Warren County (and perhaps portions of Mckean
County). However, these amounts will be just under LES Advisory
Criteria of 3 inches/12 hours.
Min temps early Saturday will vary from the upper 20s across the
higher terrain of nrn and wrn PA, to the l-m 30s elsewhere.
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.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
The stacked low pressure over moves over the Canadian Maritimes.
The mean WNW boundary layer flow off the Great Lakes will be
persistent with multiple narrow bands of mainly lake effect
snow expected to spread a little more inland (developing south
across the Laurel Highlands) and last into Sat Night.
Clouds will be pesky and linger across much of the CWA right
through the day Saturday.
Max temps Saturday will be slightly colder across the north and
west, but slightly warmer than today (Friday) across the
Susquehanna River Valley. Still, these numbers are within a few
degs of normal for the first part of Dec.
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Late Sat night and Sunday brings a brief respite as high pressure
builds east across the state. Sunday evening and night, a period
of light snow is looking likely as a northern stream shortwave
races through the region with a burst of warm advection. QPF looks
to be on the order of a tenth of an inch or less, but occurring
overnight many places could see their first coating of snow of the
young season by Mon morning. Snow is more likely in the NW than
Another ridge moves through on Monday as progressive weather
pattern becomes more active. On Tues there is decent agreement in
bringing the SW US upper low up through the Ohio Valley as a
shearing out shortwave and diffuse surface low. Unless cold air
damming traps enough chilly air in the low levels to make for some
freezing rain, the precip type with this midwest system looks to
be mainly rain.
The end of the week brings some model disagreement with the
GFS/GEFS being faster than the ECMWF with the next large upper
trof and frontal system. Either way, precip looks like a good bet
around the Thu/fri period as all solutions eventually bring this
trough through. So predictability is increasing, but timing issues
remain. Best bet for precip at this point is mainly rain over the
SE as decent push of warm air lifts ahead of the system, with a
rain/snow mix further north where warm air will not infiltrate as
Behind the trough, looks like a chilly weekend in store with a
potential sharp dropoff in temps.
.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
Mid afternoon satellite loop continues to show stratocu covering
most of Central PA, associated with slow moving low pressure over
Southern Quebec. Cold air flowing over Lk Erie is producing lake
effect snow showers across Northwest Pa.
Will stick with persistence at KBFD/KJST and forecast predominantly
MVFR conditions. However, there will still be ocnl dips to IFR
with passing snow showers at KBFD.
Downsloping flow east of the mountains should result in
progressively better (high-end MVFR and low-end VFR cigs) conditions
further east. Mainly VFR at KIPT/KMDT/KLNS, with temporary dips to
MVFR cigs overnight.
Ocnl snow showers will likely drop vsbys into the 1 1/2SM-3SM
range at KBFD/KJST late today through Saturday.
The entire region will continue to see breezy conditions last
through the next 24 hours. Bukfit soundings support sustained winds
between 10-20kts across the entire region today and tonight, with
occasional gusts around 25kts (especially late tonight and early
Saturday) as mean winds in the lowest 5 kft agl veer by about 20
degrees to around 290 Deg.
Sat...SHSN with ocnl IFR vsby at KBFD/KJST, mainly in the morning.
Sun...Light snow/reduced vis possible at night, mainly NW Mtns.
Mon...No sig wx expected.
Tue...Mixed precip/low CIGs possible across the nrn mtns, with a
mdtly heavy 0.50-1.00 rainfall expected across much of Central and
NEAR TERM...La Corte/Lambert