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536
FXUS61 KCTP 121932
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
332 PM EDT Sat Jul 12 2025

.SYNOPSIS...
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* Continued seasonably warm and humid through much of the coming
  week
* Although at least hit and miss, afternoon and evening focused
  showers and thunderstorms are expected through Monday, the
  most widespread activity, featuring locally heavy downpours,
  will be Sunday afternoon and evening.
* At this point, Tuesday looks like the driest day of the next
  seven
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Weak shear and high PWAT is resulting in many tall showers, but
not many have ltg at this point. The downdrafts and cold pools
they are generating seem to be killing them off after 30 minutes
or so. They do lay down boundaries along the outflow edges,
which help other showers grow up. The nearly stationary showers
do have PWAT of 1.5-1.75" to use. But, the short duration of
rain over the same area is thus far keeping any flood worries
low. The higher elevations seem to have done just about all they
can for now. Without additional triggers and very weak forcing
aloft, there will be additional flare ups, but a quiet period
may be in store for a couple of hours. Expect these same
conditions to last into the early evening. But, we`ll have to
keep an eye on every cluster of showers/storms to make sure they
behave similarly.

Stabilization should help kill things off early this evening.
But, a few -SHRA could run around all night. Dewpoints in the
70s and U60s will not allow us any relief from the muggy nights
of late. Marine layer of moisture seeks to move back into Sern
PA and perhaps into UNV/IPT later tonight. But, the signal is
less strong/less certain than it was for Fri night. Will paint
high sky cover for the SE half of the CWA tonight. Fog is also a
probability, but perhaps not as widespread as Fri night. Will
mention patchy fog for much of the area.
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&&

.SHORT TERM /SUNDAY/...

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Morning cloud deck over the SE will dissipate, and perhaps
faster than Sat AM. Sfc wind will still be light and out of the
SE. Shear will be light, but not near-zero like it was on Sat,
generally 15-20KT. An actual short wave trough will be advancing
through PA on Sunday. PoPs will be the highest (70-100) they`ve
been for many days. PWAT a little higher than today/Sat. With
all that going for it, the atmosphere is primed for more heavy
rainers, but also more chc for severe gusts. Hail (at least
large hail) less likely than severe wind gusts on Sun aftn and
evening. SPC keeping on with the MRGL risk for most of our CWA,
and WPC Slight risk for excessive rainfall also continues. Both
seem well-founded. We have been considering a flood watch for
Sun, but we`ll let the rain fall where it wants today and show
it`s hand before making a FFA. Passing it onto the later shifts.

Temps a secondary problem for Sun. The NBM looks fine with 80s
and perhaps someone touching 90F in srn Franklin Co.
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&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
The aforementioned slow-moving cold front will continue to
progress across central Pennsylvania Sunday night and throughout
the day on Monday, with current guidance progged to have the
surface cold front overhead by sunrise on Monday. Little
residence time in the warm sector will allow for less
destablization across the area, with dry air west of the cold
front allowing for drier conditions to prevail west-to-east as
the day progresses. Front pulls further east and out of the area
Monday evening into Tuesday morning, allowing for a brief
period of no precipitation across central Pennsylvania through
the morning hours on Tuesday.

As the cold front continues across central Pennsylvania on
Monday, PWATs in the 1.50"-2.00" range will continue to promote
some potential for isolated instances of flash flooding across
eastern Pennsylvania which remains consistent with WPC`s
Marginal Risk for Excessive Rainfall. Flooding potential will
also be exacerbated by antecedent rainfall, so will need to
continue to monitor rainfall trends through the weekend with
regards to the flooding threat on Monday.

Large-scale pattern remains fairly consistent; however,
allowing for continued chances for diurnally driven showers and
thunderstorms across central Pennsylvania throughout much of the
long-term forecast period. Focus for precipitation Tuesday
afternoon/evening will be stationed across the southern tier of
Pennsylvania with increasing coverage during the afternoon hours
on Wednesday, Thursday, and Friday.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
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Convection fired up on the high ground early this aftn, but has
since consolidated in one cluster near Gettysburg and THV.
Expect some more SHRA/TSRA to pop up, but they will be isolated
to scattered, and much of the time before 10PM/Midnight should
be VFR. Then, we fully expect another marine layer cloud deck
to form and push inland. If anything, it could go a little
farther westward by early Sunday, with a low-level E-SE flow in
place for at least parts of the region. KLNS, KMDT, and KIPT
have high confidence (70-80%) of restrictions. We`re less sure
at KUNV and KAOO (30-50%), while low cloud development seems
unlikely at KJST and KBFD. Fog is again expected, but only a
30-60pct chc of LIFR conditions out away from the IFR/LIFR
marine stratus deck.

Forcing moving in from OH on Sunday will cause a better/more
widespread round of SHRA/TSRA. The better shear thru the atmos
will help them move a little bit quicker. We have a high level
of confidence in a better-organized cluster of storms moving
from W-E across Central PA in the aftn and evening hours. While
this is mainly outside of the 18Z end time of this package,
we`ll likely add more mentions of TSRA with later packages.

Outlook...

Mon...Cold front nears, but may stall out/not pass through
completely. Widespread SHRA/TSRA, mainly southeast.

Tue-Wed...Mainly VFR. Isold PM TSRA poss, mainly south.

Thurs...Sct/Nmrs SHRA/TSRA.
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&&

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

&&

$$

SYNOPSIS...Jurewicz/Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...NPB
AVIATION...Dangelo