325
FXUS61 KCTP 031731
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
131 PM EDT Wed Sep 3 2025

.SYNOPSIS...
* Sunny and dry today as high pressure remains in control.
* A series of cold fronts will bring a risk for strong
  thunderstorms Thursday and Saturday.
* Temperatures trend below normal again next week with high
  pressure and dry weather prevailing.

&&

.NEAR TERM /THROUGH TONIGHT/...
Another gorgeous day on tap with high pressure bringing dry
conditions and plenty of sunshine. Fair weather cumulus will
develop again by early afternoon as high temperatures get into
the middle 70s to low 80s. Light southerly winds  A light
shower or two cannot be ruled out in the Laurel Highlands later
this evening as moisture ahead of an approaching cold front
begins to advect north.

Southerly winds will back to southeasterly or easterly overnight
to the east of the Susquehanna Valley. This will support low
clouds and/or fog along and east of US-15. Farther west, high
clouds will begin to move overhead by daybreak ahead of the next
weather maker. A few showers are possible northwest of I-99/I-80
corridor overnight as well, though intensity/rainfall
accumulation should be insignificant. Lows on Thursday morning
will range from near 50 in the typical cool spots in the
northwest mountains to near 60 in the Lower Susquehanna Valley.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
Under a prevailing upper trough, a mid-level vorticity maximum
will rotate through the Mid Atlantic on Thursday accompanied by
a surface cold front. Convection associated with the cold front
should be fairly weak by daybreak Thursday as it moves across
Lake Erie and into northwest PA. As the front moves east,
these showers and storm should reintensify as they encounter sufficient
moisture with dewpoints in the upper 50s to low 60s, marginal
instability (up to 750 J/kg), and ample shear (30 - 40kts).

Convection allowing models depict potential for two distinct
rounds of showers/storms. The first would be associated with the
aforementioned line of storms that will advance into southeast
PA by later afternoon and evening. The second would be along
the surface cold front, which likely struggles to get past the
I-99/I-80 corridor by Thursday evening. The SPC has issued a
Marginal Risk for nearly all of Pennsylvania. The best shear
will be across northern PA into New York, while the best
instability will be well south of the region (Southern
Appalachians). Pennsylvania will have sufficient amounts of
instability and shear to support a marginal threat of damaging
winds.

Highs on Thursday will range from the mid 60s in northwest PA
where more clouds/precipitation will keep temperatures at bay,
to the mid 80s in southeast PA where most of the day should
remain sunny or at least partly cloudy before convection
arrives. On Thursday night, lower dewpoints will filter into
northwest PA behind the cold front allowing temperatures to drop
into the mid 40s. Farther southeast, more clouds/lingering
showers will keep temperatures much more mild in the upper 50s
to lower 60s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
For the long term period, a prevailing upper trough across the
eastern US will remain in place, perhaps lifting a bit by the
middle of next week. On Friday, high pressure will briefly
regain control of the region giving way to mostly sunny skies,
dry conditions, and another seasonably mild day. Noting that
Thursday`s cold front will get hung up across the Central
Mountains, it will still be rather humid on Friday afternoon in
southeast PA.

By Saturday, a stronger cold front (compared to Thursday) will
sweep through the Commonwealth and bring a renewed chance for
showers and thunderstorms. There remains some uncertainty
regarding how much instability will be in place ahead of the
front, but scattered strong to severe thunderstorms seem like a
good bet. As is typical with these systems, the best chance for
severe will likely be in southeast PA and an SPC Marginal Risk
is probable for Saturday.

After the cold front sweeps through, another fall-like pattern
will settle in for the second half of the weekend and into next
week. The airmass moving overhead will be the coolest of the
season so far. Highs in the 60s and 70s will pair with lows in
the 30s to 50s. Frost or freeze conditions seem like a good bet
for the typical cool spots in northwest PA early next week along
with river valley fog. Abundant sunshine and dry conditions are
favored, with increasing moisture and chances for rain toward
the middle to end of the week.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Partly cloudy to mostly sunny skies will continue to be dominant
throughout the remainder of this afternoon and into the first
part of tonight before high pressure begins to break down. Fog
is unlikely overnight given increasing winds ahead of the
frontal system expected to arrive on Thursday.

High clouds will increase overnight ahead of an approaching cold
front and will gradually thicken across northwest PA into the
early morning. All TAF sites are expected to remain VFR through
12Z, though. Similarly, rain should stay west of BFD and JST
until after 12Z. Confidence is increasing on timing for low
clouds and precipitation to arrive in the northwest (BFD) around
14Z. Showers will gradually expand eastward throughout the
morning and into the early afternoon. Probability for thunder
remains less than 50 percent given that instability will remain
rather limited, and the best dynamics for strong storms will be
north of the NY boarder. However, there is still a good signal
for impactful storms to occur across all of central PA Thursday.

Outlook...

Thu...Widespread SHRA/TSRA ahead of a cold front.

Fri...Showers lingering, mainly across the east.

Sat...Chance of SHRA with TSRA possible.

Sun...Clearing, breezy.

&&

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

&&

$$

SYNOPSIS...Banghoff
NEAR TERM...Banghoff
SHORT TERM...Banghoff
LONG TERM...Banghoff
AVIATION...Bowen