460
FXUS61 KCTP 162007
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
407 PM EDT Sun Aug 16 2026

.WHAT HAS CHANGED...
* SVR Watch anticipated shortly for a portion of our area.

&&

.KEY MESSAGES...
0) Severe thunderstorms moving through western PA should arrive
in the next 1-1.5 hrs.

1) Rain from possible thunderstorms late this afternoon and
evening could be locally very heavy over the Laurel Highlands
and South-Central Mountains. There is still potential for some
heavy rain to fall over the Lower Susquehanna Valley and Central
Ridge-and-Valley region.

2) High pressure yields a short dry window for late Monday
afternoon through Wednesday morning, before more storms arrive
Wednesday afternoon into Thursday.

&&

.DISCUSSION...
KEY MESSAGE 0: Wavy line with a big LEWP (Line Echo Wave
Pattern) headed toward the CWA from the west. Expect it to
arrive shortly (5-6PM). SPC SVR Watch coordination call is
likely to occur soon. We were not included in the watch earlier.
Can only imagine that was due to the uncertainty of the cloud
cover clearing some and development of llvl instability. Too
much cloud = too little CAPE/threat for severe gusts to reach
the ground. The forcing may not be enough to sustain the severe
storms too far eastward/into the mountains - it`s still pretty
cloudy in State College. We will see. At the least, the SW
(Cambria and Somerset and perhaps all the counties in the
current Flash Flood Watch will have some threat of severe gusts.
There is a non-zero chance of tornadoes, too. Those would be
along the gust front/line. Cold pool is developing, so the line
may have that supporting the possible survival of the line into
the central and south-central mountains.

KEY MESSAGE 1: Rain from possible thunderstorms late this
afternoon and evening could be locally very heavy over the
Laurel Highlands and South-Central Mountains. There is still
potential for some heavy rain to fall over the Lower Susquehanna
Valley and Central Ridge-and-Valley region.

Line of storms moving in is moving steadily, quickly. The
opportunities for flooding may, therefore, be decreased.
However, the FFG in Somerset and portions of Cambria and nrn
Bedford counties is still hovering just above 1.2". So, we can`t
let our gaurd down as some of the radar estimates in PBZ`s area
have been above that. The inflection point of the LEWP is the
place most likely to have the ability to exceed FFG as the rain
in that feature could last just a little longer at any one
loaction than the more-windy parts of the line. Despite the
instability showers and storms back in wrn OH, the only worry
for flooding and severe thunderstorms should be in the next
couple of hours.

   ------------------------------------------------------

KEY MESSAGE 2: High pressure yields a short dry window for late
Monday afternoon through Wednesday morning, before more storms
arrive Wednesday afternoon into Thursday.

A cold front moves through Monday. Dewpoints don`t drop much at
all until later in the day Monday. So, there will still be
plenty of time on Monday for instability to develop and pop
showers and perhaps a thunderstorm or two during the daytime. By
sunset, these will be gone as dry air and loss of heating kill
them off. Dewpoints drop into the 50s for many Tuesday morning.
Large scale subsidence should yield a mostly sunny day, then.
Return flow Tuesday night and Wed will bring the humidity up and
a cold front will approach on Wednesday. Storms are expected
mainly in the Wed-Wed night timeframe, but speed of the CFROPA
will determine if all/part of Thursday will be dry. If showers
linger, they would be over the south.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
The first round of rain associated with a Mesoscale Convective
Vortex will be moving out of our eastern zones by 20Z.

All attention then turns to a fast moving LEWP with several
distinct bow echoes and likely 65+ kt wind gusts racing east to
the PA/OH state line ATTM.

The storms should maintain their strength as the surge east
along a llvl instability max with an orthogonal mid-level wind
max helping to accentuate wind gust potential across roughly the
SW half of the of the CWA.

Timing of the likely strong bow echo(es)is 21Z at KJST, 22Z at
KAOO and 2220Z at KUNV. Westerly sfc wind gusts of 40 KTS or
greater likely.

Instability as measured ne way by Mixed Layer CAPE was very
minimal and just a few hundred J/KG at 18Z - to the east of a
KBFD to KUNV and KMRB line (where the sfc warm front is ATTM).

The airmass is notably cooler and more stable (temps in the 60s)
across the Susq Valley and points east. Therefore the
aforementioned storms will likely lose a decent amount of punch
by the time they reach the RT 11/15 corridor.

Areal coverage and intensity of the convection will gradually
decrease this evening and the warm front will stay pretty much
in place tonight and stay as the focus for briefly heavier
rainfall rates.

Late tonight, mainly IFR CIGS and MVFR vsbys will occur along
with generally isolated SHRA/TSRA.


Outlook...

Mon-Tue...VFR most of the time. Chance of showers/tstm Monday.

Wed-Thu...Afternoon showers or a TSRA with brief restrictions
possible. Otherwise, VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 PM EDT this evening for PAZ024>026-
033>036.

&&

$$

WHAT HAS CHANGED...Dangelo
KEY MESSAGES...Dangelo
DISCUSSION...Lambert/Dangelo
AVIATION...Lambert