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019
FXUS61 KCTP 081712
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
112 PM EDT Tue Jul 8 2025

.SYNOPSIS...
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* Flash flooding and damaging thunderstorm wind risk this
  afternoon and evening across the southeastern portion of
  central PA
* Similar setup for Wednesday with renewed damaging wind and
  flash flooding risks focused over southeast PA
* Continued seasonably warm and humid with scattered afternoon
  and evening thunderstorms through the weekend
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Thunderstorms are beginning to develop early this afternoon
along and ahead of an outflow boundary associated with morning
convection that has moved in from the Ohio Valley. As this
convection moves eastward with time through the afternoon, it
will encounter a more unstable and sheared airmass, likely
helping it to take on a more linear mode. With this evolution,
the likelihood of damaging wind gusts will increase.

Pwats eclipsing 2" over southeast PA will support a flash flood
threat where any tstms train. We issued a flood watch starting
18Z today for a portion of the Lower Susquehanna Valley in
coordination with WFO LWX. In addition to the robust and
anomalous pwat values, very efficient warm-rain processes could
lead to rain rates >2"/hr at times resulting in potential
instances of flash flooding.

Ahead of the rain, there also remains some concern for max HX
values to reach or exceed the century mark in parts of the LSV.
However, not thinking that this will be widespread enough to
warrant a Heat Advisory.

Hires models show the majority of showers/storms will shift to
the east before midnight (in fact, most guidance has the bulk of
the convective activity winding down before 8 PM). Min temps
will be a bit cooler than last night, with fog likely forming
in the valleys through the predawn hours Wednesday.
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&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Similar overall synoptic setup on Wednesday & Thursday with
gradual southward shift to the severe t-storm and FF risk areas
coincident with zone of max PW. Conditions will remain humid and
with daytime highs in the 80s.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The forecast for Friday and the weekend is more uncertain, with
some guidance suggesting a break in the unsettled pattern, and
others suggesting active weather continues. An active pattern
would favor continue heat/humidity while a quieter pattern could
support the intrusion of lower dewpoints and more refreshing
conditions.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A very sluggish, weak cold frontal boundary extended from near
KELM to KPIT at daybreak this morning, preceded by a surface
trough over the Delaware Valley.

The very shallow and just slightly cooler/marginally drier air
behind the front has trapped low stratus and stratocu with IFR
to low MVFR conditions across much of far western PA, Ohio and
Western NY. The southeast half of PA was generally VFR with only
scattered clouds and a bit of haze/light fog with just a few
spots coming in with MVFR Vsbys.

The clear skies to the east and extensive low clouds through
this morning over the west will greatly increase the temp
gradient east to west across the front as strong heating occurs
in the mainly clear air with a much slower warmup west of the
front. Any IFR CIGS for the next several hours will be across
the Laurel Highlands and NW Mtns.

MVFR could linger into, or through this afternoon at KBFD, while
KJST should hold onto MVFR conditions until around 16Z, before
seeing an improvement/lifting of the low cloud bases.

Previous Disc...

Muggy air with sfc dewpoints in the upper 60s to low 70s
covered much of the SE 2/rids of the state at 06Z and these
conditions will persist ahead of this front across much of
Central and SE PA, while slightly cooler air with an 8-10 deg F
drop in dewpoint values will occur across the NW part of PA
today.

A few additional showers could develop by midday today, but
showers and thunderstorms will become more prevalent as we head
into the afternoon. Brief restrictions are possible everywhere
except BFD, with storms starting in the vicinity of a line
extending from JST/AOO to UNV to IPT and then moving east-
southeastward and affecting MDT and LNS later in the
afternoon/early evening.


Outlook...

Tue PM...Showers fade, fog possible across much of the region
into Wednesday morning.

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

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

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
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Flood Watch until midnight EDT tonight for PAZ057-059-065-066.
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&&

$$

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