670
FXUS61 KCTP 101832
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
232 PM EDT Thu Sep 10 2026

.WHAT HAS CHANGED...
* Increased POPS for late night showers across the Laurel
  Highlands tonight and a slight chance for a showers Friday
  afternoon across the Scent and SW zones.

&&

.KEY MESSAGES...
1) Showers and perhaps a brief thunderstorm are possible over
the southern tier of PA late this afternoon/evening and perhaps
a few more showers late tonight. Dry conditions for Friday
before unsettled weather returns for the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1: Showers and perhaps a brief thunderstorm are
possible over the southern tier of PA late this afternoon/
evening and perhaps a few more showers late tonight. Dry
conditions for Friday before unsettled weather returns for the
weekend.

A cold front nearly bisecting PA from NE to SW will push slowly
south through the rest of the state this afternoon and evening
before stalling out just south of the Mason/Dixon line tonight
and Friday.

A few weak waves of low pressure riding east along this boundary
well bring periods of showers to Southern PA, and perhaps even a
brief thunderstorm late this afternoon or early this evening
across the Laurel Highlands. Only isolated showers are expected
north of US Route 22. Rainfall will vary greatly from near zero
in some spots to as much as 0.25+ inch where a brief
thunderstorm occurs given MU CAPE climbing to between 750-1000
J/KG for a few hours late this afternoon.

Larger scale, more subtle forcing beneath the right entrance
region of a 130 kt upper jet stretched from Lake Huron to the
Middle St Lawrence River Valley will help to produce a few light
showers across the NW and Ncent Mtns of PA late today and early
evening, but QPF will be limited to a few or svrl hundredths of
an inch in most spots up north.

The aforementioned surface cold front won`t likely push through
the southern third of the CWA until this evening, so there will
be additional SHRA today with up to 60 pct in Somerset Co. A
stray shower (no thunder) could also affect Warren/McKean Cos as
the cool air aloft helps create some very weak instability
along the NY border and the cold front passes. However,
instability over the CWA will be low (<500J/kg in the far SW),
so only some isolated thunder is expected - and only in the
Laurels. The risk for heavy rain has decreased markedly through
the last 48 hrs of model runs, and the WPC ERO MRGL risk area
won`t touch PA anymore (stays to our S) with the new guidance to
be issued soon. The most-possible time for rain will be the
afternoon and early evening as some of the weak convection moves
in from the SW. The dewpoints don`t come down until the front
arrives (mid- late morning N, close to sunset in the S). So, it
may still feel a little muggy today, esp from I-80 southward
with 65-70F Tds all day long.

High pressure builds behind the cold front, giving way to a dry
and mainly sunny Friday. AM valley fog is almost a given. The
extent of the fog is a question, but we`ll paint it in all the
normal nrn valleys at this point.

As SFC high pressure moves well off the Mid Atlantic and
Southern New England Coast, low level moisture lurking just
south of the Mason/Dixon line Fri night will push steadily NE
across the state on Saturday within broad llvl flow from the
south to southwest. A notable axis of streamline convergence
shifting gradually east across Central PA late Sat afternoon/Sat
night will provide increasing llvl theta-E advection and
numerous showers with a few to several tenths of an inch of
rainfall likely across at least the SE half to two thirds of
the CWA by early Sunday. A few PM TSRA possible Saturday and/or
Sunday afternoons, especially over the western mtns. A more-
active (wetter) pattern is in store for Mon-Tues. But, the flat
upper ridge over the southern half of the CONUS will make it
difficult for deep moisture to make it into PA ahead of any
shots of atmos forcing. The week could end dry as the upper
ridge pumps up over the central CONUS.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Westerly flow prevails today, which will continue to hold around
10kts for the rest of the day. Gusts in the 15-20kts range will
continue this afternoon before growing weaker in the 6-8pm
range. with the frontal passage, the flow regime will be mostly
out of the north overnight and into tomorrow with lighter winds
expected. The stream of mid to high level clouds will clear
behind the front during the overnight. Paired with light winds
under high pressure, this will favor areas of radiation fog
overnight. This looks most likely outside of the Lower
Susquehanna Valley where mid-level clouds ahead of the front may
linger & mitigate fog development.

For the rest of the day, a passing shower isn`t out of the
question at the JST and AOO (10-20% chance) but most
precipitation is expected to remain off to the south closer to
the Mason Dixon Line. A boundary has been noted near the Pa/NY
boarder with more enhanced cumulus and spotty showers, so a
passing shower and brief drop to MVFR ceilings may occur at BFD
this afternoon as well.

Outlook...

Fri...VFR conditions expected.

Sat-Mon...Primarily VFR conditions, with some potential for
afternoon SHRA/TSRA on at least a hit and miss basis.

&&

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

&&

$$

WHAT HAS CHANGED...Lambert/Dangelo
KEY MESSAGES...Lambert/Dangelo
DISCUSSION...Lambert/Dangelo
AVIATION...Teare/Lambrech