-- Discussion containing changed information from previous version are highlighted. --
201
FXUS61 KCTP 112009
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
409 PM EDT Fri Jul 11 2025

.SYNOPSIS...
* Continued seasonably warm and humid with near to above normal
  temperatures into mid July
* Daily doses of drenching thunderstorm downpours capable of
  producing isolated wind damage
* Episodes of rain continue this weekend into early next week
  with the strongest wet signals on Sun-Mon
* Driest, but not entirely dry, timeframe may be Tues-Wed

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
Cu popped off the ridges and continues to be the generation
point for most/all of the SHRA thus far. As more SHRA and their
boundaries interact with each other, these boundaries will be
additions to the purely terrain-driven convection we have early
this aftn.

The mixed-layer CAPE is increasing per latest mesoscale analysis
trends. So, the SHRA should turn into TSRA as we warm even just
a couple of degs F this aftn. Highest PoPs are placed in the
central mtns for the aftn and early evening as the current mass
of SHRA and associated meager forcing slides eastward a little.
Evening time should bring stabilization, but not sudden. Some
SHRA/TSRA may linger close to midnight. The bigger threat with
any of the tallest TSRA will be heavy rain out of something
slow-moving/drifting. But, an isold gust into the 50s is not
totally out of the question.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
More muggy conditions are in store tonight. As the SHRA/TSRA go
away, some fog is expected to form, mainly in the valleys. With
fog being so random this morning, we can`t argue against
including it for any/all of the CWA. Min temps will generally
match the morning dewpoints: M60s-L70s. Expect the fog to burn
off by 13Z. That should result in another day with weak forcing
and mainly pulse SHRA/TSRA in the aftn and evening. They should,
like Friday`s convection, be terrain-induced at first and drift
away as they mature into the meager shear profile (<20kts).
The risk for severe gusts/hail remains low (general thunder
from SPC), and the risk for flooding may be only a little
higher but still only in the marginal category factoring in the
lower shear (vs Fri) and slower cell movement, and the slightly
lower PWAT values (1.5" vs 1.75" Fri).

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
-- Changed Discussion --
Unsettled pattern continues through the weekend and into the
beginning stages of next week with highest signal for
precipitation on Sunday with a cold frontal passage across the
region. Ample instability, shear, and moisture will bring about
some potential for severe thunderstorms along and ahead of the
front; however, model timing differences do continue into this
forecast cycle, which could limit severe potential. Heavy
rainfall is also expected with these storms, with PWATs
approaching 2.00" during the afternoon/evening hours. Best
moisture at this point seems focused over eastern Pennsylvania,
where highest month-to-date rainfall totals have been observed;
however, a couple of days (relatively) dry conditions could
allow for some relief before the next batch of heavy rainfall.

Confidence continues to increase in much of central Pennsylvania
getting an extended break in the rainy summer pattern next
Tuesday and Wednesday. This "dry" signal is reflected in the
latest medium range models and ensemble guidance which shows sfc
high pressure/upper level ridge moving into the area in the
wake of the aforementioned frontal system. There does remain
some uncertainty on eastern extent of the frontal system with
some potential for the front to get hung up across southeastern
Pennsylvania throughout this period, which will keep SChc PoPs
in this timeframe.

Unsettled pattern returns for all of central Pennsylvania with
increasing humidity and heat allowing for a return to the
typical summer-time pattern that has been observed recently.
-- End Changed Discussion --

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Terrain-induced SHRA/TSRA covering the Laurels this aftn, and
starting to spread to other parts of the airspace over Central
PA. As these storms slide off of their terrain hot-spot, they
are interacting with other storms and cold pools and generating
boundaries for more convection to form. The peak heating will be
the peak of convection today, with a downturn in the early
evening. Thus far (18Z) only one cell has made TS
over central PA today, but many more should form as we get
even slightly hotter. Not much should survive past 10 PM. The
least likely airfields to get wet (and a reduced flight
category) are MDT and LNS. BFD should be out of the woods by
22Z. All other Terminal Forecast airfields (JST/AOO/UNV/IPT) are
much more likely to have deep convection swirling around and
get in the vicinity. But, have held mentions of TSRA to just
PROB30 at this point due to the uncertainty of when & where the
cells will be from hour to hour.

With stabilization, the wind goes calm. There will be some fog
form, pretty much all over the airspace, but especially in the
valleys and where it will have rained in the past 9-10 hrs.
Some meso mdls depict a limited incursion of marine moisture/low
clouds into MDT & LNS before sunrise. However, that should
break up and put them back into the same boat as all other
airfields for Saturday = scattered SHRA/TSRA with 30-50pct chc
of rain/reduced cigs/vis at the airfield. Since most of these
will be after 18Z, we haven`t mentioned them in the TAFs just
yet.


Outlook...

Sun...Widespread SHRA/TSRA ahead of a CFRONT.

Sun night-Mon...CFROPA. Widespread SHRA TSRA, mainly SE.

Tue...Mainly VFR. Isold PM TSRA poss S.

Wed...Sct SHRA/TSRA poss area-wide.

&&

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

&&

$$

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