218
FXUS61 KCTP 031620
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1220 PM EDT Thu Jul 3 2025

.SYNOPSIS...
* Scattered storms late this afternoon and very early evening as
  a cold front moves through. Some may be accompanied by strong
  gusty winds and hail.
* Drier/less humid/more comfortable conditions are likely for
  Independence Day.
* Trending warmer and more humid but rain-free this weekend
* Hot and unsettled weather returns next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Weak sfc ridging and deep layer subsidence across much of PA
that was located between 2 jet segments and within the
descending portions of one thermally indirect circulation (100
kt jet diving SE across the Glakes) and the thermally direct
branch (mid Atlantic Piedmont to Coastal Maine jet segment).

Plenty of morning sunshine has allowed sfc based CAPE to grow to
around 2500 J/KG across Western PA with a temporary relative min
over the Eastern Third of PA.

The left exit region of the Glakes Jet max will brush across
the NE third to half of the CWA late this afternoon and early
this evening, interacting with the approaching sfc cold
front/Lake Erie Breeze and accentuating UVVEL for some fast,
southeast- moving discrete TSRA (Supercells and mini-bows)
capable of producing localized 60-70 mph downburst gusts and a
few instances of quarter to golfball sized hail. Strong low
level storm relative inflow and slightly curved 0-3 KM
hodographs along relatively cool mid level temps and a Wet Bulb
Zero level of about 9 KFT AGl supports the threat for large
hail.

Pertinent parts of the Previous Disc...

Deep layer shear of 40-50KTs at the peak could be enough to
make some supercells, but mostly clusters. However, we will be
under the descending area of the curved jet max at 5H. That is
the ingredient which could keep the convection suppressed
somewhat. SPC has continued the Day1 Outlook exactly as the old
Day2 = most of the CWA is in the MRGL risk area with a SLGT risk
barely touching the far eastern two cos. Will continue to
mention TS with small hail and gusty winds. The worst of the
storms will likely be off to our east.

Some lingering SHRA will last until just after sunset in the SE,
but it`s only worth a 20 PoP for isolated coverage. After the
front passes, which will be mid aftn in the N, and early evening
in the S, the air will dry out with sfc dewpoints into the 50s
by sunrise Friday.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Friday looks like a stellar Independence Day. No risk of any
precip, and humidity getting very low during the afternoon. Have
strayed from the NBM dewpoints for Fri and Sat aftns, with
Friday being the largest deviance. Light N wind and good
sunshine Fri. Very dry air just above the sfc in the AM and
mixing to ~5kft in the aftn could drop dewpoints into the 40s
across the Allegheny Plateau and M50s in the SE. That may not be
enough of a move, but will start with that. Maxes on Friday of
U70s to M80s are very seasonable, and we`ll probably see a few
degs of uptick in temps Sat aftn. High pressure will provide a
dry time for both days. A little fog will be had in the valleys
since it gets close to 50F in the nrn mtns Fri AM, but the dry
airmass will work against it. Dewpoints are going to be low
enough on Sat AM that there won`t be much, if any, fog. Then,
the wind turns Swrly, and humidity levels start to creep upward
during the long holiday weekend, but no rain.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Compared to previous guidance, today`s model runs have slowed
down with the arrival of precip associated with a shortwave
trough late Sunday. Most of the day looks hot and mostly sunny
with highs in the upper 80s. PoPs increase into Monday as the
trough arrives. Monday should be the hottest day with L90s SE
of the Allegheny Front. Forecast uncertainty increases Tuesday
and Wednesday, as several ensemble members show showers/storms
lingering as the front slows down, while much of the
deterministic guidance has drier air pushing in.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
The main focus through the 12Z Friday will be a shortwave that
will traverse the region and bring isolated showers and
thunderstorms to portions of the area this afternoon. The
surface cold front associated with this upper level shortwave
will move in during the afternoon and will trigger a few
thunderstorms over eastern PA. This cold front will be largely
moisture starved; however, given the instability in the eastern
portion of PA it is possible isolated to scattered storms may
cause some impacts. These thunderstorms will have the best
chance of impacting IPT, MDT, and LNS, while areas farther to
the west likely remain dry. Confidence still remains low on
development and coverage of afternoon convection.


Outlook...

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

Mon-Tue...Thunderstorms developing in the afternoon.

&&

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

&&

$$

SYNOPSIS...Lambert/Dangelo
NEAR TERM...Lambert/Dangelo
SHORT TERM...Lambert/Dangelo
LONG TERM...Colbert
AVIATION...Lambert/Bauco/Bowen