524
FXUS61 KCTP 101800
AFDCTP

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

.WHAT HAS CHANGED...
* No major changes

&&

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

&&

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

Sfc cold front was located from near KELM and KELZ WSW to around
KBFD and KGKJ at 16Z and drifting slowly SEWD.

Slight veering of the low-mid level flow from west to the west-
northwest throughout the day today will help to keep the bulk
of any showers (and possibly a low-topped TSRA) confined to the
southern tier counties of Penn this afternoon and evening with
sfc dewpoints in the mid 60s to near 70F.

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 this afternoon 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. Low level moisture lurking
just south of the Mason/Dixon line Fri night will advance NE
across the state on Saturday as SFC high pressure moves well off
the Mid Atlantic and Southern New England Coast. This will lead
to some showers spreading NE across the region with 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...Dangelo
AVIATION...Teare/Lambrech