000
FXUS61 KCTP 311810
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
210 PM EDT Mon Aug 31 2026

.WHAT HAS CHANGED...
* Adjusted POP/Wx to better align with Day 2-4 SPC SLGT risk

&&

.KEY MESSAGES...
1) Late summer surge of heat and humidity brings multiday severe
thunderstorm and excessive rainfall threat to kickoff September

&&

.DISCUSSION...
KEY MESSAGE 1:

A series of mid level impulses tracking eastward along the
northern periphery of an expansive 500mb ridge will interact
with anomalous moisture/instability and strong WNW flow aloft
to promote a multiday severe storm and excessive rain risk
across portions of CPA Tuesday-Thursday. A surge of late summer
heat (max temps 80-90F range) with dewpoints in upper 60s to low
70s will result in a very moist boundary layer with impressive
MLCAPE values in the neighborhood of 2-3k J/kg given mid level
lapse rates around 7 C/km. Forecast soundings also show robust
deep layer/effective shear values and appreciably curved,
sizable low level hodographs. As such, a couple of supercells
will be possible. Severe wind and hail are the main threats,
though a tornado or two may also occur. On balance, the
environmental parameters are quite bullish for severe storm
potential. However, timing (time of day), speed, and location
of each mid level impulse will be key factors that could
modulate the bullish severe setup to some extent. Increasing
MUCAPE values late tonight through Tuesday morning suggest
storms/severe risk likely won`t be tied to the typical diurnal
cycle. The severe risk will shift to the south of CPA by
Friday, but an upper trough passage suggests some lingering
shower activity into the weekend.

The late summer heat is forecast to peak Tuesday and Wednesday
with very warm nights +10-20F above the historical average and
max heat indices approaching advisory levels/century mark
across parts of south central PA. The upper ridge is forecast to
retrograde by the end of the week which allows for increased
troughing and a return to more seasonal temperatures for early
September.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Intermittent showers will continue across the Commonwealth this
afternoon, primarily over north-central Pennsylvania
(KBFD/KIPT), as weak shortwaves ride along a NW-SE oriented
temperature boundary located the PA-NY border. With that said,
mainly isolated showers are expected this afternoon as the
primary swath of ongoing showers continues eastward, with even a
few breaks in cloud cover showing on satellite. However, slowly
building instability (MUCAPE increasing SW to NE to around 1000
J/kg) alongside abundant moisture (PWATs approaching 2") and
breaks of sunshine may promote the development of isolated
heavier showers/thundershowers later this evening/evening
(though less than PROB30 likelihood at any one site).

Following any convective showers or thundershowers that develop
this afternoon, another lull in activity is expected later this
evening before another round of spotty showers overnight, with
overnight fog/low stratus possible as well. While widespread
cloud cover would be a limiting factor for fog, plenty of
moisture, occasional showers, and light winds may result in
ceiling/visibility restrictions. Overnight fog/low stratus will
mix out Tuesday morning, with a downtrend in shower activity &
improvements to VFR expected by Tuesday afternoon. Otherwise,
westerly winds will climb to around 10-15 kts with gusts around
20 kts, primarily for the western terminals
(KBFD/KJST/KAOO/KUNV) where the pressure gradient will be
tighter.

Outlook...

Tue-Fri...Scattered SHRA/TSRA with brief restrictions possible;
morning fog possible.

Sat...SHRA/TSRA trending less likely as cold front moves
southward across the Commonwealth; morning fog possible.

&&

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

&&

$$

WHAT HAS CHANGED...Steinbugl
KEY MESSAGES...Steinbugl
DISCUSSION...Steinbugl
AVIATION...Teare