170
FXUS61 KCTP 101714
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
114 PM EDT Mon Aug 10 2026

.WHAT HAS CHANGED...
* Level 2/5 severe thunderstorm risk expanded eastward for
  today. SVR TSTM Watches #552 and #553 in effect through mid
  afternoon and early evening respectively.

&&

.KEY MESSAGES...
1) Thunderstorms with severe wind gusts and locally heavy rain
will be likely this afternoon and evening

2) Humid with rounds of heavy showers and strong thunderstorms
focused over southwest Pennsylvania through midweek

&&

.DISCUSSION...
KEY MESSAGE 1: Thunderstorms with severe wind gusts and locally
heavy rain will be likely this afternoon and evening

1 pm EDT update: Blossoming, albeit still bkn line of strong to
severe TSRA extending from the Ncent Mtns SW to the Greater
Pittsburgh area at 17Z with a movement to the east at 30-35 kts.
2 distinct MCVs (one along the PA/NY border and the second just
to the SE of KPBZ will enhance both rainfall and deep layer
speed and directional shear, with several mini supercells
breaking out to the east and SE of both mesoscale features.

Expect updrafts to strengthen as they move into the zone of max
SB CAPE of 2000-3000 J/KG (across Scent PA and developing into
the Lower Susq Valley.

Mesoscale warm front to the east of both MCVs will lead to a 1-2
hour period of training TSRA with heavy to briefly torrential
rainfall rates (over 2 inches per hour) and localized flash
flooding possible.

Previous...

Small clusters of sub-severe storms over the NW quad of PA at
0730Z have been weakening as they track to the east per radar
and IR satellite trends. This activity appears to be associated
with subtle vortmax feature near the OH/PA line. We adjusted
POPs higher near/north of I80 to account for this as the storms
continue to track eastward through daybreak.

The question remains what the convective evolution will be from
around midday through the afternoon and evening. HREF/REFS
model data favors intensification of t-storm clusters reaching
the northwest PA vicinity by midday and tracking east-southeast
through the afternoon. If this scenario plays out, storms will
likely pose a risk for damaging wind gusts within a humid and
moderately unstable airmass. SPC expanded the level 2/5 SLGT
risk eastward and now includes all of the Lower Susquehanna
Valley.

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

KEY MESSAGE 2: Humid with rounds of heavy showers and strong
thunderstorms focused over southwest Pennsylvania through
midweek

Model trends are focusing primary risk for severe storms and
heavy rain across southwest PA on Tuesday. This area lies
closest to the equatorward edge of the westerlies within very
moist instability gradient. SPC and WPC have outlooked this
area (SW PA) with a a level 2/5 severe storm risk and 2/4
excessive rain risk.

Rounds of showers and storms remain possible through midweek.
Multiple shortwave disturbances will traverse the northern tier
and interact with a slow moving frontal zone. The combination
of rich low level moisture, instability and repeated forcing
along the boundary will support some potential for periodic
clusters of storms with locally heavy rainfall. WPC excessive
rain outlooks (EROs) have shifted farther to the south/west and
only clip the far southwest portion of the CWA on days 3-5 or
Wed-Fri.

The end of the week into the start of the weekend looks less
humid (more refreshing) as push of relatively cooler and drier
air accompanies seasonably strong/Canadian high pressure
building southeast from the Upper Midwest.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
12Z TAF Update: A loosely organized cluster of showers and
thunderstorms is moving across central PA as of 1030Z, located
around KJST/KAOO/KUNV, corresponding to lift along the leading
edge of higher PWATs (up to around 1.5") and instability (MUCAPE
to 1000 J/kg). This activity may continue into our eastward
terminals between 12Z-14Z Monday (KMDT/KLNS, and perhaps KIPT
depending the northern extent of this convection), with
additional rounds of convection to be monitored later today.
Otherwise, discussion points remain largely the same as with the
06Z TAF discussion provided below.

Previous discussion: Remnant MCS over western PA as of 06Z will
track eastward through the morning hours, likely decaying as it
encounters limited instability (MUCAPE of 100-250 J/kg east of
the Allegheny Ridge). Timing this feature out across the
terminals, PROB30s for -TSRA were included between 08Z-14Z, with
confidence still low regarding the system`s evolution.
Relatively steep mid-level lapse rates of around 6-7 C/km with
eastward extent may allow for the system to persist for longer,
while relatively limited moisture (PWATs of around 1") and the
lower MUCAPE favor a continued downtrend. For this time, the
feature was timed out in case it persists.

Low-level moisture may support a period of MVFR cumulus as the
boundary layer deepens during the morning/afternoon hours, with
higher confidence in MVFR ceilings over our westernmost
terminals (KBFD/KJST) & decreasing confidence with eastward
extent. Otherwise, the main window for aviation hazards is
expected to be the afternoon/evening from scattered
thunderstorms, with moderate instability (MLCAPE of around 1500
J/kg), decent support for gusty downdraft winds (DCAPE around
1000 J/kg), and favorable wind shear for organized convection
(35 kts of 0-6 km wind shear) in place. This parameter space
supports multicell clusters and squall lines capable of gusty to
locally severe wind gusts. Timing of these potential storms
will depend on upstream initiation and organization, with cold
pool development potentially accelerating storm motion.

Storm coverage/intensity is expected to decrease after 00Z
Tuesday, though additional showers/thundershowers can`t be ruled
out. VFR is currently favored at most terminals Monday night,
with the main exception being KBFD where onshore flow from the
Great Lakes may bring restrictions due to low stratus and mist.


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...Lambert/Steinbugl
KEY MESSAGES...Lambert/Steinbugl
DISCUSSION...Lambert/Steinbugl
AVIATION...Teare