255
FXUS61 KCTP 151131
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
731 AM EDT Sat Mar 15 2025

.SYNOPSIS...
High pressure will move to the east today as a strong storm
system will approach from the west. The cold front of this
system will push across Central PA on Sunday, producing a
soaking rain and perhaps some stronger thunderstorms. The wind
will get gusty Sunday even away from any thunderstorms. One
cooler day on Monday will be followed by a warm up as ridging
moves in from the west and settles overhead for mid-week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The low clouds are racing NW vs last night`s slow progress. They
are also lower then Fri AM thanks to the higher dewpoints. Fog
is dipping the visby at the usual, upslope spots when this type
of pattern (marine layer) is underway. The ridgetops and SE-
facing slopes could have some DZ this morning, too. Once the sun
starts to mix things up, the clouds should start to break up. It
shouldn`t be quite as complete of clearing as was the case on
Friday. These clouds will be tougher to get rid of. Even when
they do break up, there will be plenty of mid-high clouds to
filter the sun. This should keep maxes in the 50s, except over
the far wrn fringe of the CWA and right along the MD border
where they should eclipse 60F. The WAA over wrn PA will hold
enough moisture and forcing added in should make sct SHRA in the
aftn. But, only W of Rte 219. Wind gusts in the 20s will be
common in the nrn tier and wrn highlands during the aftn after
the heating has mixed things up.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
The first part of the night will hold a resurgence in the low
clouds. These will get widespread again, and perhaps a little
thicker and farther N & W than Sat AM. Thus, patches of drizzle
are expected to be found on the ridges and S/SE-facing slopes.
The wind won`t die off too badly despite the high llvl stability.
On Sunday, the high stability of the llvl air could protect us
from the very strong srly winds just aloft (2-3kft) and from a
more-widespread and more-severe threat (that is, worse than the
current SPC MRGL risk).

The forecast rolls along with high confidence in the big picture
and even the medium details. While mesoscale features will
dictate the eventual hour-by-hour elements, all the words of the
previous forecast discussion (included below) about Sunday hold
true:

Sunday looks like the most active day of weather, as the cold
front pushes across Central PA during the PM hours. We`ll
discuss the forecast by hazard type:

NON-CONVECTIVE WINDS: Most guidance brings 60-70KT SSW winds as
close as 2-3kft aloft, so it won`t take much to tap into. That
being said, antecedent stability likely prevents surface winds
outside of convection from getting too strong. Perhaps the mtn
tops could have 40+MPH gusts outside of any convection or decent
mixing. But, many other places are progged to be too stable to
get high gusts unless there is mixing due to deep
convection/thunderstorms.

CONVECTIVE HAZARDS: Much of the guidance has only a few hundred
J/kg of pre-frontal CAPE Sunday afternoon. However, decent large
scale forcing is likely to support a round or two of low-topped
convection that may not produce much lightning. Poor mid-level
lapse rates/weak boundary-layer heating will likely limit the
severe wx threat. But with very strong low-level shear/winds,
there remains some risk for damaging wind gusts. The cold
front and associated convection should exit the region Sun
evening, but some SHRA may linger.

FLOODING: PWATs with this system will be between 1 and 1.5
inches, which is in the >99th percentile for this time of year
and indicates these showers will be efficient rainmakers. Latest
ensemble mean qpf supports a widespread 0.75 to 1 inch of
beneficial rain across Central PA Sunday with little risk of
flooding. However, orographic enhancement associated with a
pre-frontal southerly flow is likely to result in somewhat
higher rain totals across the mtns north of I-80, where flash
flood guidance is a bit lower (~1"/3hrs), so can`t rule out some
minor flooding issues in this region Sunday PM.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Fair and closer to seasonable weather appears likely Monday, as
surface ridging builds southeast into PA. Dry and warm
conditions are then expected Tue and Wed, as upper level
ridging builds over the East Coast and the surface ridge slips
east of PA. EPS mean 850mb temps peak around 10C Wed, supportive
of max temps potentially exceeding 70F over parts of the area.

Medium range guidance supports the chance for a round of
showers with a cold front passage next Thursday. Latest ensemble
plumes indicate rainfall will not be very significant with this
fast-moving front.

Blustery and colder conditions are likely behind the front
Thursday night into Friday, with scattered rain/snow showers
accompanying the upper trough passage, mainly over the N and W
Mtns.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Low clouds are creating MVFR and IFR conditions at all TAF sites
except BFD this morning. These clouds will be much slower to
dissipate than they have been in recent mornings and will
likely stick around across the southeast (MDT/LNS) through the
entire TAF period. A line of thunderstorms over Ohio will weaken
as it moves into the more stable airmass over Pennsylvania, but
a few showers will be possible at BFD later this morning and
into the early afternoon.

With southeasterly low-level flow remaining in place low clouds
will redevelop yet again overnight across much of the region.
The bigger concern tonight is low-level wind shear as a 50 to
60+ knot low-level jet moves into Central PA ahead of an
approaching frontal system. The base of the shear layer will be
quite low over the western airfields, with 40-50 knot winds
potentially making it all the way down to 1000 feet. This will
likely only translate to surface wind gusts of 20 to 30 knots as
it looks to be fairly stable in the low levels.

Showers will begin to enter the region from the west ahead of a
cold front around 09Z Sunday. Ceilings will lower to MVFR at BFD
and JST as the showers move in. As of now, it looks like any
thunder will hold off until after 12Z, but can`t completely rule
out a few thunderstorms approaching the western TAF sites
towards daybreak.

Outlook...

Sun...Widespread SHRA, TSRA possible, especially across SE PA.
Restrictions probable.

Mon...Windy and colder with clearing skies.

Tue...VFR with lighter winds.

Wed...VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Dangelo/Banghoff
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Fitzgerald
AVIATION...Bauco