-- Discussion containing changed information from previous version are highlighted. --
943
FXUS61 KCTP 130108
AFDCTP

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

.SYNOPSIS...
* 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

&&

.NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --
Weak shear and high PWAT is resulting in isolated, slow-moving
showers and thunderstorms early this evening, some of which are
anchored by, and backbuilding over favored upslope area of
terrain features. Interaction with outflow boundaries from
earlier (and current) convection is also a factor in this
otherwise weakly-forced/low shear environment.

Two recent Flash Flood Warnings have been issued for 1) Somerset
Cty in SW PA and 2) Franklin Cty in Scent PA. These areas are
located along a subtle warm front across SW PA and weak meso
low near KHGR/KFDK where a band of MAX 925-850 mb Moisture Flux
Convergence was noted.

Hourly rainfall rates (that have maxed out near 3 inches/hr
across Franklin County, will gradually decrease between 01-03Z
and we don`t really see any other areas of imminent
training/terrain anchored convection ATTM.

POPS will stay in the 10-30 percent range overnight as several
weak shortwaves embedded in the SW flow aloft drift across the
aforementioned weak frontal boundary over SW and Scent PA, where
highly localized, additional rainfall of up to 1 inch is
possible through 05Z.

Previous Disc...

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.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY NIGHT THROUGH 6 PM SUNDAY/...
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.

&&

.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 /01Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Expect isolated, slow-moving SHRA/TSRA to continue through 05Z
Sunday, especially between between KCBE and KHGR and KMRB (and
possibly as far NW as KMDT) where a stationary front at the
surface, intersects with a weak sfc low pressure center in that
area.

Elsewhere, look for VFR through shortly after midnight local
time, then a gradual decrease through MVFR to possibly IFR
VSBYS between 08-13Z Sunday.

Additionally, we fully expect another marine layer stratus cloud
deck to form and push inland bringing IFR to LIFR conditions
between 06-13Z Sunday (mainly impacting KLNS, KMDT and KIPT).

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.
-- End Changed Discussion --

&&

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

&&

$$

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