Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 190440

Area Forecast Discussion
National Weather Service State College PA
1240 AM EDT Mon Mar 19 2018


Fair and dry conditions will continue tonight into Monday.
The start of Spring will marked by a rain/snow mix with light to
moderate accumulations possible across south central Pennsylvania
Tuesday into Wednesday. Cooler than average temperatures will
dominate the pattern through the end of the week, with the next
opportunity for precipitation coming this weekend.



Valley winds have really dropped off the last few hours. Clear
skies will continue to prevail overnight. Dewpoints in the
teens will allow temperatures to cool off nicely and lows
will fall into the teens and 20s, with dewpoints slowly rising
to around 20F in all but the NE. Some stratocu should develop
over upstate NY and try to slide into the northern mountains as
a weak cold front slips through, but dryness of airmass should
erode most of these clouds as they drop southward overnight.



Monday will remain fair and dry, but with a gradual increase in
clouds late in the day from S to N. Low level flow starts off
light from the NW, but gradually turns around to the SE ahead
of a low pressure system progged to track to our south Mon night
into Tue. Highs will range from the mid 30s north to around 50



A pair of low pressure systems tracking to the south of PA
across the southern Mid Atlantic region Mon. Night-Tue will
eventually consolidate into a deepening cyclone off the New
England coast Wed-Thu. It looks increasingly likely that Spring
2018 will start off on a wintry note with accumulating snow a
good bet across far south central PA on Tuesday. Model guidance
was in pretty good agreement QPF-wise Mon. Night into early
Tuesday, but made a northward shift later Tue. into early Wed.
The best period for accumulation will be early Tuesday morning
and again during the late evening/overnight hours into early
Wed. morning. Several inches are possible south of the PA
Turnpike, particularly in the higher elevations but late-season
factors will come into play. Timing and intensity will be key,
with accumulation -especially on roads- very difficult this time
of year from mid morning to mid afternoon due to the strong
March sun. So just how disruptive the snow is on travel/AM Tue.
commute is still in TBD with road conditions likely varying
from wet to slushy or snow covered. We added the Tue. Night
period to the storm total snow which now stretches from 00Z Tue
to 12Z Wed. The late-season factors including marginal
temperatures and elevation/precipitation-rate dependence
continue to make this a challenging forecast.

Pattern favors mainly dry wx and below average temperatures
through the late week period, with a cold wind on the backside
of the coastal storm. Models show the next opportunity for
precip arriving this weekend as low pressure streaks east from
the Plains.



For the 06Z TAFS...will only have lower clds in at BFD for a
few hours...concern is the airmass is rather dry for much in the
way of lower clds this morning.

More information below.

Model data continues to support a high confidence forecast of
VFR conditions and light wind over most of central Pa through
Monday. However, there is a chance of MVFR stratocu dropping
from NY state into northern PA early Monday morning associated
with the passage of a weak cold front. Any stratocu that does
affect northern Pa should mix out by late morning, with
widespread VFR/light winds Monday afternoon.


Tue...Snow/restrictions likely southern Pa.

Wed...AM light snow possible southern tier.

Thu-Fri...No sig wx expected.



The Spring (Vernal) Equinox will be at 12:15 PM on Tuesday,
March 20. Sunrise in State College, PA will be 7:14 AM and
sunset at 7:23 PM, for a total daylength of just over 12 hours.




LONG TERM...Steinbugl
CLIMATE...Steinbugl is the U.S. government's official web portal to all federal, state and local government web resources and services.