703
FXUS61 KCTP 282126
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
526 PM EDT Sat Jun 28 2025

.SYNOPSIS...
* Scattered strong to severe thunderstorms with torrential
  downpours are possible this afternoon into the evening
* Sunday will be the best day of the last weekend of June with
  lower humidity and rain-free/dry conditions
* Stormy pattern resumes early next week with renewed risk of
  strong to severe storms and locally heavy rainfall

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
* The NWS Storm Prediction Center has issued Severe
  Thunderstorm Watch #471 for most of Central Pennsylvania until
  800 PM EDT.

* Primary threats include...
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms will increase in coverage and intensity
through the day across the watch area, ahead of an approaching cold
front.  The strongest cells will pose a risk of locally damaging
wind gusts.

Previous Discussion Issued: 1046 AM EDT Sat Jun 28 2025

Mid morning visible satellite and observational trends show low
clouds gradually eroding across the central and eastern portions
of CPA. The stratus deck will persist the longest over the mid
to lower Susquehanna Valley.

Important update in the near term is a categorical SWO upgrade
to SLGT risk from SPC along (50mi either side) of the US220/I99
corridor. Based on the 12Z discussion, the key driver behind the
increased severe tstm risk level (from 1 to 2 out of 5) was
more influence (forcing) from southern extent of weak mid level
trough crossing southern Ontario. The trailing cold front/wind
shift has not crossed Lake Erie as of 1430Z.

Hires models all generally agree in storm development
along/ahead of the weak cold front/wind shift or perhaps
prefrontal/lee trough. The longevity of low clouds could offset
diurnal heating and push back CI particularly across the
southeast zones. The other potential limiting factor in play in
terms of severe storm risk is the lack of deep layer vertical
shear <30kts. If enough instability can be realized to produce
steep low level lapse rates (with max temps projected to rebound
10-20 degrees vs. Friday) along with water loading from high PW
airmass -- that pulse to multi-cell environment would be
largely supportive of an isolated wind damage threat in the
strongest cores/storms. Overall, we are not super bullish on the
severe setup, but could easily see at least a couple of SVRs
being issued.

Last items is locally heavy rainfall: WPC has most of the area
in a MRGL risk ERO. With high pwats 1.5-2 inches, a few very
heavy/torrential downpours are likely. Storm motions are more
progressive than yesterday, so any isolated flooding concerns
would be in repeat heavy rain zones.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH MONDAY NIGHT/...
Sfc high pressure building into CPA behind the front provides a
dry period tonight through Sunday. Any clearing tonight could
result in a foggy start to the day tomorrow. Sunday will see a
return of sunshine, drying conditions, and warmer temperatures
once high pressure is in control. High temps on Sunday will
reach the low 80s across the northern tier of the commonwealth
to the low 90s near south central PA along the Mason Dixon line.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
The stormy and unsettled pattern resumes early next week with a
shortwave trough progressing through the Great Lakes sending a
quasi stationary/warm and cold front through the region Monday
and Tuesday. For now, the signal is relatively weak for rainfall
leading up to the 4th of July. However, another northern stream
front will keep low POPs in the forecast for Independence Day.
Whether or not we see precipitation for the 4th will be
dependent on how quickly the upper level low lifts out of New
England and gets replaced by building region over the central
US. Temperatures by the middle of next week are progged to be
just above to near climo.

&&

.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
Scattered showers and a few thunderstorms will continue to
drift eastward across the area, mainly south of I-80, this
evening. A localized downpour is possible.

As skies clear overnight, there is the potential for fog
development. Have hinted at this possibility in each of the
TAFs, and hit BFD the hardest where the confidence is the
highest in reduced vsbys.

After any fog mixes out, expect dry weather and widespread VFR
conds for Sunday.

The next cold front will arrive early next week. Some of the
accompanying storms could be on the strong side once again.

Outlook...

Sun...AM fog, then VFR.

Mon-Tue...SHRA/TSRA expected, with periods of fog and low
clouds overnight.

Wed...AM fog, then VFR.

Thu...Primarily VFR, although a few aftn SHRA/TSRA are
possible.

&&

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

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Tyburski
LONG TERM...Steinbugl/Bowen
AVIATION...Steinbugl/Evanego