557
FXUS61 KCTP 011121
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
721 AM EDT Tue Jul 1 2025

.SYNOPSIS...
* Stormy pattern continues as a cold front pushes through the
  region, bringing a risk of strong to severe storms and locally
  heavy downpours and flash flooding.
* Drier/less humid/more comfortable conditions are likely for
  mid to late week with a high confidence of dry weather with
  seasonable temperatures on Independence Day.
* Trending warmer and more muggy later this weekend.

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
Cluster of weak thunderstorms moving into the western mtns.
They`ve got some weak forcing behind them, so we`ll have to
account for them this morning. Lots of cloud cover right now, so
that could disrupt/delay the development of later storms. Have
kept PoPs the same after 17Z, but tweaked before.

Prev...
Weak SHRA will drift across the srn tier through sunrise. A
smattering of other weak showers will pop up through the
morning, but thunderstorms will wait until noon or just after
when we reach convective temp. The cold front to our west will
drag a little in the OH valley, but make it into the far NW late
this morning, perhaps too early to help make deep convection
for them.

As the front nears and we get hotter, convection looks like it
could be anywhere in the warm sector based on what weak
boundaries out there and terrain can do. The best forcing is
driving some convection over CVG at 09Z, and that looks like it
could be the kicker for most of our storms this aftn/eve.

The tremendously heavy rain (3-5") over nrn Lancaster Co and
other patches of 2+" over the Lower Susq over the past 18 hrs
will make them highly susceptible to even a modest downpour
today. FFG may be a bit lower there then the current (06Z)
guidance, but that did account for much of what fell last night.
NBM QPF has streaks of 1-2" in the Lower Susq, and deterministic
guidance is also highlighting the srn tier for heavy rainfall
potential in the same places. Thus, we`ve issued a Flash Flood
Watch for the SE counties. Made it a little generous/broad to
allow for a little wiggle room on placement of the
thunderstorms. But, all those counties except Franklin had very
heavy rainfall in the last 18 hrs. Maxes of U70s to U80s aren`t
far from normals.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
The front seems like it should be clearing the SE late this
evening, perhaps around midnight. Thus, the precip should be
tapering off then. The clearing anticipated behind the precip
will probably cause fog, especially in the central mountains
where they won`t have time to dry out like the NW may. Cross-
lake flow may introduce a couple of showers over the NW early
tonight. Dewpoints only dip to around 60F in BFD, but 60+
numbers remain across the rest of the CWA through morning. Most
everyone will get down to their dewpoint by morning. Have added
a bit more fog to the forecast for tonight.

Wed looks like a fair and warm summer day. The gradient isn`t
very strong behind the front, so the wind should be under 10MPH
out of the NW. maxes generally 80-85F, with a deg or two varience
in the normal cool (elevations) and warmer (urban) spots. There
is a small (20 PoP) chance for a shower over the far SE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
High pressure begins to build southwest of the region,
providing fair weather for the middle of the week and into the
weekend. Best chances for precipitation through Saturday will
remain due to a cold frontal passage across the northern half of
Pennsylvania. Cold front remains relatively moisture-starved;
however, generally think forcing will be enough to cause a
shower and afternoon/evening thunderstorm.

The biggest feature of the post-frontal airmass will be much
lower dewpoints and refreshing nights/mornings. There is high
confidence in lows dropping into the 50s and low 60s Thursday
and Friday nights, which will be a significant and welcome
change from the long-duration heat/humidity we have experienced
over the past few weeks. Independence Day activities should be
under fair skies, comfortable temperatures, and pleasant
northwest winds.

Low pressure approaching the Great Lakes by Sunday morning will
bring about increasing chances for precipitation for the second
half of the weekend and into the beginning of next week.

&&

.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
655 AM update.

A few showers south of AOO and JST as of 655 AM.

Larger cluster of showers and storms north of PIT.

Been adjusting TAFS as needed.

More information below.

415 AM update.

Not much change, a few showers tryig to form over the western
areas of central PA.

Earlier discussion below.

06Z TAFS sent.

Very high dewpoint air and southeast flow resulted in intense
rainfall rates across the east late evening, but that activity
is east of the area.

Overnight expect a wide range of conditions.

For this afternoon, flow is a bit more from the south and
southwest and dewpoints do edge down, so expect showers and
storms not to be quite as widespread and intense for the bulk
of the area. Still will be close for LNS.

For tonight, expect partial clearing, but there could still
be a shower or two across the south. Main thing will be light
winds, so fog and low clouds could form in spots.

Wednesday should feature much less shower activity, as the
drier air works into the area.

Strong dynamics with strong sun angle could trigger a few
strong storms on Thursday, especially across northern areas
at locations like BFD and IPT.

Outlook...

Tuesday Night...Clearing skies with patchy to widespread fog
possible.

Wed...AM fog, then VFR.

Thu...Primarily VFR; stray PM shower/t-storm possible.

Fri-Sat...AM fog possible; otherwise VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch from 2 PM EDT this afternoon through this evening
for PAZ036-057-059-063>066.

&&

$$

SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Banghoff/NPB
AVIATION...Martin