681
FXUS61 KCTP 121003
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
603 AM EDT Fri Jun 12 2026

.WHAT HAS CHANGED...
* Expanded heat advy into Franklin Co.

&&

.KEY MESSAGES...
1) Heat advisory still warranted, and have expanded it to the
west one county. Relief should be here for Sat.

2) Thunderstorms are expected to flare up this afternoon and
produce damaging winds. Highest coverage of and strength of
storms will be in the SErn third of PA.

3) More storms will move into PA Sunday afternoon.

&&

.DISCUSSION...
KEY MESSAGE 1: Heat advisory still warranted, and have expanded
it to the west one county. Relief should be here for Sat.

As expected for many days, the heat and humidity will remain
high through the daylight hours over the SE. Overall tweaks to
the temps/dewpoints were very few. However, we`ve collaborated
with LWX on slightly higher numbers to put enough of Franklin
Co into the low 100s on the heat index that it warranted
expanding the advisory to include them.

The passage of a cold front will usher in lower dewpoint air and
make it feel much less muggy on Sat. Afternoon RH in the 35-45%
range will feel refreshing after a couple of very humid days.
Temps will still be hot, getting into the 80s and perhaps near
90F Sat.

   ---------------------------------------------------

KEY MESSAGE 2: Thunderstorms are expected to flare up this
afternoon and produce damaging winds. Highest coverage of and
strength of storms will be in the SErn third of PA.

A large patch of low clouds has developed over the Alleghenies
and seems to be expanding. The wind from the SW should help
nudge them north and east through the morning.

The timing of the cold frontal passage may be slightly before
the atmosphere can juice up again, perhaps keeping the stability
high enough to thwart deep convection there. The cold front
should arrive in Warren Co around or slightly before 18Z, and
cross the CWA over the following 6 hours. The convergence at the
sfc is poor with nearly uni-directional flow in the morning.
Storms are possible before the FROPA, and may be well ahead of
the front as a significant sfc trough will develop to the SE.
Many of the models develop few, if any, storms NW of State
College - and some not even until past Harrisburg. PoPs will be
a generic 30-50pct across the board today based on expected
coverage.

The SPC has also kept the outlook for day1 very close to what
it was for day2. A slight risk exists over a good portion of the
CWA excepting the far NW. There is even a 30% chc of tstm wind
dmg w/in 25sm of any given point over the extreme SE part of our
CWA. That is a bit higher coverage than we usually expect on a
slight risk day. Seems logical, though, with NAMNest CAPE at
LNS nearing 3000J/kg, and moderate 30KTs of deep layer shear.
WBZ is a little higher than ideal for large hail, so the main
threat will be wind damage from increasingly organized clusters
which is not much different than yesterday/Thurs. The slightly
stronger wind aloft may help some of the storms in NErn PA spin
a bit and yield a non-zero tornado threat there.

With storm coverage expected to be sparse over some or most of
the CWA today, the risk for any downpours hitting the wetter
areas of the CWA is low. So, the risk for flash flooding is
minimal. Some places took 2 inches of precip yesterday without
much of a blip upward on local stream gauges. Of course, the
cumulative effects of repeated rainfall will likely lower FFG
overall.

   ---------------------------------------------------

KEY MESSAGE 3: More storms will move into PA Sunday afternoon.

After the drier Sat, the flow backs and the more-southerly flow
brings more-humid air back into PA. The mugginess will be
noticed the most in the SE, with the Td just nearing 60F in the
aftn. A very narrow jet buckles just a little and provides
sufficient dynamics for another afternoon and evening round of
severe thunderstorms. Arrival looks mid-late aftn NW with the
storms crossing the CWA and exiting to the SE by 10-11PM. Some
storms are possible out ahead of the front associated with the
upper dynamics. The next visit from organized storms will likely
not be until at least mid week (Thurs).

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
As we near the first day of Summer, fcst in line with the
obs. Some spots across the north and west have low CIGS
and fog. Still expect conditions to improve.

Activity over Ohio earlier has weaken as of 6 AM.

More information below.

Not a lot of change from when I did the 00Z TAF package
earlier.

For the 06Z TAFS, the main issue early on was to add some
showers to BFD and adjust showers in JST for weakening line of
showers and storms over central Ohio at 130 AM.

The other change was to add a line after sunset today, for
clearing and weakening winds.

Showers and storms largely east of the area. A few light
showers near IPT, but that is about it as of 130 AM.

Fog and low clouds have been in and out of the area since
last evening, but just enough wind to keep much of the area
with limited fog so far.

Looked over the potential for LLWS, held off for now, as
a bit borderline.

More information below.

Lower clouds and fog will likely form overnight, mainly
in areas that had rain today.

Expect winds to pick up Friday morning, with conditions
expected to become VFR again by late morning or early aft.

Have some VCSH in most of the TAFS later Friday, NAM model
not showing much potential with showers and storms. Did not
have VCSH in BFD, as even less chc there. Later shifts can
adjust more on Friday as needed.

A break on Saturday, but a stronger cold front on Sunday
will bring the potential for more strong storms on Sunday.

Outlook...

Saturday...Mainly VFR.

Sunday...VFR favored early, with restrictions possible as FROPA
brings chance of -SHRA/-TSRA later in the day.

Monday...Additional scattered -SHRA and associated restrictions
possible.

Tuesday...Still a slight chance of showers and storms.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for PAZ036-057-059-
063>066.

&&

$$

WHAT HAS CHANGED...Dangelo
KEY MESSAGES...Dangelo
DISCUSSION...Dangelo
AVIATION...Martin