Monday, November 12, 2018, 9:45 PM EST
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Area Forecast Discussion
||Wed, Dec 31, 7:00pm EST
FXUS61 KCTP 120831
Area Forecast Discussion
National Weather Service State College PA
331 AM EST Mon Nov 12 2018
A strengthening storm system tracking from the northern Gulf
Coast through the Mid Atlantic Piedmont and up the I-95 corridor
will bring rain and snow to central Pennsylvania tonight into
early Tuesday. Gusty northwest winds will deliver lake effect
snow accumulation to the northwest snowbelts Tuesday night. A
brief break in the active weather now during the midweek before
another storm system brings more rain and possible wintry
weather Thursday into Friday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Increasing clouds expected today ahead of low pressure lifting
north from the Gulf Coast. Highs in the 40s are about 5 degrees
The northern 2/3 of central PA will stay dry through early
evening. However, precipitation is likely to spread northward
into the southern tier around 7pm. Based on max TwAloft and
evaporational cooling, expect precip to start as rain/snow/sleet
mix in the Laurel Highlands/southern Alleghenies and cold rain
in the valleys the east of I-70/81.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
Precipitation will continue to spread northward through the
evening and should cross the I-80 corridor around 10pm. Initial
surge of moisture into the marginally cold air should result in
a brief period of rain/snow/sleet over the central ridges before
turning to cold rain.
The northern tier higher elevations remain the target area for
wet snow accumulation late tonight into early Tuesday morning. A
blend of WPC/NBM paints a stripe of 1-3" along and northwest of
a line from Elk to Tioga County, with max amounts centered over
eastern McKean and northern Potter County. Hires data suggests
the rain/snow line advances northward to KBFD-KELM line by 09Z
as warm air surges in aloft. This may result in some patchy
freezing rain/drizzle on the ridgetops from the Laurel Highlands
into the northern Alleghenies as precipitation tapers off toward
12Z. The low level flow should shift to the northwest by the end
of the period, signaling a change to CAA/westerly flow regime.
.LONG TERM /TUESDAY THROUGH SUNDAY/...
As the low continues to deepen as it moves into New England,
expect precipitation to continue through Tuesday afternoon with
snow most likely across the higher elevations from the Laurel
Highlands into the north-central Alleghenies (mainly west of
I-99 and north of I-80). Additional accumulations are likely
over these areas.
It will turn windy and colder Tuesday night into Wednesday with
lake effect/orographic snow showers and perhaps some squalls.
Wind gusts 30+ mph are likely in the tight gradient behind the
departing storm. Additional lake effect accumulations are likely
into Wednesday. Wednesday looks very similar to (11/10) and
even colder Wednesday night with lows in the teens to mid 20s.
High pressure will provide improving conditions into late week
with temps moderating a bit on Friday.
Another shot of cold air will sweep into the region next
Saturday with accompanying scattered Lake Effect snow showers.
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR with mid-high clouds increasing today in advance of a storm
system that will bring rain and snow to the airspace tonight
into early Tuesday morning. Expect a steady lowering of ceilings
late today into early tonight with a high confidence in
widespread IFR/MVFR through 12Z Tue. Precipitation will spread
from south to north 00-06Z with cold rain in the southeast and
snow/mix northwest. Westerly flow behind the departing storm
should spell improving conditions across central and especially
eastern portions of the airspace by Tuesday afternoon. Lake
effect and upslope snow showers will likely maintain MVFR/IFR
restrictions across the western 1/3 of the airspace into Tuesday
Tue...MVFR/IFR early becoming VFR central/east PM. Gusty winds
PM 20-25kts. Snow showers western 1/3.
Wed...MVFR cigs NW trending VFR.
Thu-Fri...A new storm system will bring a return of widespread