Area Forecast Discussion
Issued by NWS State College, PA-- Remove Highlighting --
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FXUS61 KCTP 210641
Area Forecast Discussion
National Weather Service State College PA
241 AM EDT Tue Mar 21 2017
Scattered rain showers early this morning will give way to
seasonably mild conditions for the first full day of Spring.
Cold air will plunge back into the area Tuesday night through
Wednesday before retreating during the second half of the week.
A period of snow or ice is possible ahead of the returning warm
air later in the week. A milder pattern will persist through
the weekend with opportunities for rain into early next week.
.NEAR TERM /THROUGH TONIGHT/...
High res guidance shows current pcpn activity with leading
frontal boundary weakening as it drifts east across the southern
1/2 of the area through daybreak. Temperatures over the higher
terrain along and to the north of I-80 could support rain/snow
mix with no accumulation expected. Rain ends early and is
followed by a mainly dry and seasonably mild day with highs in
the 45-55F degree range.
Secondary/arctic cold front pushing southeast across the Lower
Great Lakes this evening will traverse the area overnight into
early Wednesday morning. Noticeably colder air will follow with
temperatures falling into the teens and 20s by 22/12z. Gusty
winds will add to the chill with apparent temps in the single
digits and teens. Some snow showers/flurries are also possible
as strong CAA spills downwind of the lakes but short northerly
fetch and dry air should limit any accumulation to a brief
coating over Northern Alleghenies.
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Brisk and cold conditions on Wednesday could be the coldest air
we see until fall. High temps will be -15 to -25 degrees below
average for late March, but record low maxes do not appear to be
in jeopardy. Lingering snow showers or flurries in the morning
should taper off by the afternoon. 1040mb high pressure builds
over the area Wed night, setting up a pretty cold night for this
time of year. Favorable radiational cooling and dewpoints in the
single digits and teens should be a good proxy for minimum temps
with single digit lows over the northern tier. Would not rule
out a few of the usual cold spots dropping into negative
WAA pattern quickly follows what could be winter`s last gasp
with moderating temperatures into the second half of the week.
Models indicate risk for snow/ice mix ahead of the warm air as
pcpn spreads into retreating shallow cold layer near the
surface Thursday night-AM Friday. Max POPs are over the NW 1/3
of the area based on a multi-model consensus blend.
.LONG TERM /FRIDAY THROUGH MONDAY/...
The Warm front will likely lift into New York State and the
warm sector should expand NE cover the entire CWA Friday
afternoon through most of Saturday with temps surging well into
the 40s to around 50F Friday, then into the lower 50s (north) to
lower 60s (south) on Saturday.
Timing and location of the deep cold air and associated 1040+
sfc high over southeastern Canada will play a key role in the
storm track of a southern stream wave that will be sheared east
from the Mid Miss Valley late Saturday...through the Ohio River
Valley...Central Appalachians and Mid Atl Coast Sunday through
Pops for rain/showers will increase Saturday night through
Sunday night, but capped them off in the likely range at this
Shallow cold air could backdoor us from the NE later in the
weekend per the continued/consistent trend of the 12Z EC and
GEFS. This could lead to some precip type issues across
northern PA at a minimum.
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --Low pressure will track south of Pa early today, spreading
scattered rain showers and falling CIGS across the region.
Latest HRRR and 20/21Z SREF probability charts suggest IFR
conditions are possible between 10Z-14Z at JST/BFD, MVFR
conditions are likely at UNV/AOO and perhaps no sig reductions
at the lower elevations airfields of eastern Pa, including
Any showers should push east of the region around 12Z, as the
low pressure system passes off the Mid Atlantic Coast. However,
residual low level moisture ascending the Allegheny Mountains
could create lingering MVFR stratocu at BFD/JST into early
THIS afternoon. The arrival of high pressure and drier air
should result in widespread VFR conditions by late in the day,
even at BFD/JST.
Wed-Thu...No sig wx expected.
Fri-Sat...Showers/reduced CIGS possible, mainly BFD.
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