909
FXUS61 KCTP 100010
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
810 PM EDT Sun Aug 9 2026

.WHAT HAS CHANGED...
* Added mentions of wind, hail, and heavy rain to the TS in the
  wx grids for late tonight into Mon evening.

&&

.KEY MESSAGES...
1) Multiple rounds of showers and thunderstorms possible on
Monday, heavy downpours, gusty winds, and hail possible.

2) The unsettled pattern continues after Monday with daily
afternoon storms chances through mid week.

&&

.DISCUSSION...
KEY MESSAGE 1: Multiple rounds of showers and thunderstorms
possible on Monday, heavy downpours, gusty winds, and hail
possible.

The overwhelming challenge to the forecast for Mon (and Tues) is
still the wild card of how severe the early-day convection will
be, and what the clouds and rain will do to the later
possibilities of convection. Without any change to the guidance
from the 18Z packages, we haven`t made any meaningful changes to
the message nor PoPs. We did start mentioning the chars of TSRA
with a blanket of SLGT risk SVR over the area and MRGL-SLGT risk
Ex Rain covering the CWA.

Previous...
The remainder of Sunday will remain dry and pleasant with fair
weather cumulus clouds overhead. The forecast becomes tricky
after today though with multiple rounds of storms possible for
monday, but low confidence in the evolution and placement of the
large scale forcing.

An MCS developing over Lake Michigan will slowly continue to
progress eastward through the rest of this afternoon and into
tonight. This feature and how it evolves with time will play a
key role in thunderstorm development over central Pennsylvania
tomorrow. The timing of the MCS in the morning as if moves over
Lake Erie along with multiple 850mb shortwaves will serve as
the catalysts for storm initiation.

Current model solutions depict two main rounds of storms for
tomorrow. One is in the morning along the outflow of the MCS.
Morning CAPE in northwestern PA will be between 500-1000J/kg
and available bulk windshear will be around 25kts. These storms
will favor a linear storm motion and could contain strong to
severe wind gusts as they propagate along the MCS cold pool.
While the environment that early in the morning is not entirely
favorable for stronger storms, the possibility is still there.
The second round of convection would be most likely to initiate
in the mid to late afternoon as a second shortwave comes across
the Allegheny Front. The environment at this time would more
supportive of severe storms if they can initiate. Widespread
CAPE between 1500-2000J/kg is being depicted in the mean 12Z
HREF solution along with area wide 30kts of bulk shear. This is
the solution with the highest confidence as of right now, but
the question will come down to where storms initiate and the
eastward extent of those storms. If the MCS cannot maintain its
current strength and speed overnight then Monday could look
entirely different than what was just described.


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

KEY MESSAGE 2: The unsettled pattern continues after Monday
with daily afternoon storms chances through mid week.

After Monday we can expect continued daily afternoon chances for
showers and thunderstorms at least through Thursday. Repeated
short waves rotating around a larger upper level low, along
with moisture injections from the gulf, and daily highs in the
upper 70s to mid 80s will provide ample instability and lift for
afternoon storms. It is too early to say with any confidence
whether or not these storms will pose a significant severe
threat, as these will mostly be typical afternoon summer time
storms. However, the SPC has painted an area of 15%
probabilities for severe weather on Wednesday that includes
portions of southwestern PA.

While severe weather confidence remains low for Tuesday through
Thursday, there is likely going to be a daily threat for
isolated to scattered flash flooding. Model mean PWATs are
between 1.5-2" meaning these storms will likely be efficient
rain producers, and given current antecedent conditions it
would not take a ton of rain to cause problems in areas that
have seen repeated flash flooding over the past week.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
VFR conditions will continue through the rest of the day and
into the overnight hours. Beyond that, much uncertainty remains
in the forecast with models struggling with the progression of
the MCS currently across N OH, trending slower and less intense
than current radar suggests. Model guidance appears to be on a
trend of weakening showers/storms which appears to be the most
plausible solution so have kept some continuity with the
previous forecast outside of speeding up SHRA at JST in the
early morning hours based on current radar trends. Have retained
TSRA mentions in BFD as well but honed them in on a tighter
window based on a combination of RAP/HREF model guidance.

The forecast for the afternoon continues to be highly dependent
on the evolution of this morning convection. Possibilities
range from scattered showers and thunderstorms with minimal
impact, to a line of strong to severe thunderstorms moving
across most of central PA. JST/AOO appear most likely to see
thunderstorms prior to 18Z with HREF ensemble guidance
outlining ~30% probabilities of TSRA at UNV/IPT in the 18Z-21Z
window and MDT/LNS in the 21-23Z window. Given this signal, and
that there is likely to be less shower activity this far east,
have pushed PROB30s for the 00Z TAF cycle with coverage still
the main uncertainty across the entire area.

Outlook...

Mon-Thu...Scattered showers/storms. Restrictions possible.

Fri...Mainly VFR. A few showers or storms possible over
southwestern PA.

&&

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

&&

$$

WHAT HAS CHANGED...Dangelo
KEY MESSAGES...Dangelo/Bowen
DISCUSSION...Dangelo/Bowen
AVIATION...Bauco/Beaty