304
FXUS61 KCTP 090850
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
450 AM EDT Wed Jul 9 2025

.SYNOPSIS...
* Scattered damaging wind gusts and flash flooding are possible
  across portions of south central and southeastern Pennsylvania
  this afternoon and evening
* Continued seasonably warm and humid into mid July with daily
  chances for afternoon and evening thunderstorms

&&

.NEAR TERM /THROUGH TONIGHT/...
Areas of fog and low clouds early this morning will give way to
a mix of clouds and sunshine. Max temps will be in the 80-90F
range from NW to SE with slightly reduced humidity levels based
on sfc dewpoints trending about 5 degrees lower vs. Tuesday.

500mb trough will move slowly eastward today across the Great
Lakes/Ohio Valley. HREF data depicts a belt modestly enhanced
southwesterly mid level flow that will contribute to slightly
higher bulk shear values ~30kts than in recent days. This may be
offset to some extent by drier/less humid air that will result
in lower instability/CAPE across most of CPA. The area to watch
will be over the southern tier particularly into the lower Susq
Valley given juxtaposition of max CAPE/shear and 1.5-2" PWAT.
Latest CAMs show T-storms initiating over far southwest PA into
WV as shortwave energy rotates into the Upper Ohio Valley then
ramps up in both coverage and intensity spreading eastward to
the I-95 corridor by 00Z. For now, there appears to be a
stronger signal for a heavy rain axis and corresponding flash
flood risk farther to the south over northern MD, but we issued
a flash flood watch from Adams to Lancaster County which could
be impacted especially if convection trends farther to the north
and west through the day. Showers and storms could persist into
the overnight period in parts of south central/southeast PA
before shifting to the north/east after 06Z.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Diurnal heating of a seasonably moist and weakly capped
boundary layer will result in afternoon thunderstorms through
late week over CPA. Precipitable water values look to trend
lower vs. previous days. This will reduce the excessive rainfall
and flash flood risk while remaining sufficient to support the
potential for wet downbursts and isolated wind damage. SPC has
maintained a level 1 marginal risk for both D2/Thu and D3/Fri.
Typical mid July summertime temperatures expected with daytime
highs in the 80-90F range and lows 60-70F.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Daily chances for afternoon/evening thunderstorms continue over
the weekend and into early next week with max/min temps trending
near to slightly above normal for mid July.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
In the wake of a cold front, areas that have received locally
heavy rainfall this evening will have higher potential for fog
and widespread visibility restrictions overnight. At this time,
have progged AOO/UNV towards LIFR conditions overnight; however,
model guidance indicates some potential at all airfields except
for MDT/LNS. Have stuck with guidance trends; however, will
have to continue to monitor trends at MDT/LNS with heavy
rainfall and fog potential overnight.

After sunrise on Wednesday (12Z Wed - 18Z Wed), model guidance
shows fair agreement with respect to restrictions being lifted
by 12Z for most airfields. The 18Z TAF package does set the goal
post slightly wider, with widespread restrictions lifting
closer to 13-14Z give some lingering low-level moisture in RAP
model soundings.

Outlook...

Wed...Best chance for storms and restrictions in southern PA.

Thu-Sun...Potential for showers and thunderstorms, mainly
aftn/eve.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch from this afternoon through this evening for
PAZ064>066.

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Lambert/Colbert
AVIATION...NPB/RXR