279
FXUS61 KCTP 140130
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
930 PM EDT Thu Aug 13 2026

.WHAT HAS CHANGED...
Bumped fog probabilities slightly later into tomorrow morning,
other than that, few major changes at this time. A dry night
in store for central PA.

&&

.KEY MESSAGES...
1) Generally quiet pattern statewide looks to persist through
Saturday with any precipitation chances confined to the
southern tier of the state.

2) Sunday brings a return to wet conditions with showers and
thunderstorm chances returning.

&&

.DISCUSSION...
KEY MESSAGE 1: Generally quiet pattern statewide looks to
persist through Saturday with most precipitation chances
confined to the southern tier of the state.

Finally getting an evening with nothing on the radar as of
mid evening. Expect the overnight to remain dry. Any showers
are expected to be after sunrise on Friday.

More information below.

The upper level jet streak is anticipated to traverse through
Ontario and into New England, passing over New York/Northern
Pennsylvania. As the right entrance region passes over
Pennsylvania, it will interact with a remnant MCV from
convection that is currently ongoing in the Midwest. This ascent
should allow for another round of clouds some shower
development in the southern tier of the state later tomorrow.

Main timing looks to be from the late morning to mid-afternoon.
The ascent may allow for some spotty afternoon showers
elsewhere, but dry air filtering in from the north should keep
things fairly isolated.

As these features pass through and drier air filters in from the
north, skies should start clearing Friday evening into Saturday.
This will make for some relatively less humid conditions to
begin the weekend with any isolated rain chances looking to
remain in the southwest.

KEY MESSAGE 2: Sunday brings a return to wet conditions with
showers and thunderstorm chances returning.

A low pressure system moving through Canada will allow a stalled
frontal boundary to move through Pennsylvania as a warm front
on Sunday. This will bring a moist airmass, with PWATs possibly
exceeding 2" into Pennsylvania. With a secondary low likely
forming closer to Pennsylvania at the intersection of the warm
front and a trailing cold front, this will invigorate
development of showers and thunderstorms. With a cold front
draping across Pennsylvania Sunday night, multiple rounds of
showers/thunderstorms may be possible into the night.

As it stands right now, ensemble guidance has the northern tier
of Pennsylvania targeted for highest rain probabilities and
totals. Exact timing of this activity and how fast/slow the
cold front moves through will likely become clearer as we
approach Sunday. With such high PWATs and potential for multiple
rounds/training activity, flooding potential will need to be
watched. Should the cold front stall/move slower, activity may
linger into Monday morning. After that passage, the start of
next week is showing signs of high pressure moving over the
region.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
Scattered shower activity along the surface convergence
boundary over central PA has largely dissipated as mid/high
level clouds from Ohio Valley convection stream overhead &
surface temperatures cool as sunset approaches. These clouds
look to persist overnight, introducing uncertainty regarding the
extent of overnight radiational fog. For this reason, I leaned
more optimistic compared to the GLAMP, which appears to be
trending towards less fog as well, and closer to HREF guidance.
However, BKN/OVC mid-high level clouds are less efficient at
mitigating against radiational fog vs. BKN-OVC low clouds, so
patchy fog with visibility restrictions (primarily around
KBFD/KJST/KAOO/KUNV) still seem possible.

Patchy morning fog will mix out soon after sunrise Friday, with
VFR favored & light winds of ~5 kts through the rest of the TAF
period. With that said, intermittent MVFR ceilings are possible
in the morning & early afternoon, primarily at KJST/KAOO, as
diurnal/upslope cumulus develop. Towards the end of the 00Z TAF
period, high pressure nosing in from Canada may push a weak
backdoor cold front into northern PA. A northeasterly wind shift
is expected behind the front, which could reach KBFD/KIPT
around or after 00Z Saturday. Winds may gust to around 15 kts
with the frontal passage, primarily if it moves through during
the evening before the boundary layer stabilizes, with lower
wind gusts (5-10 kts) if it moves through later into the night.

Outlook...

Sat...AM fog possible, then VFR. Warm front moves in and
SHRA/TSRA likely W Sat night.

Sun...Restrictions possible in showers/thunderstorms.

Mon...CFROPA by Monday morning. SHRA/TSRA ending Mon AM. Mainly
VFR for most of the day.

Tue...Mainly dry.

&&

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

&&

$$

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