000
FXUS61 KCTP 281754
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
154 PM EDT Tue Jul 28 2026

.WHAT HAS CHANGED...
* Flood Watch expanded to include portions of south-central
  Pennsylvania until 1 AM tonight.
* Severe Thunderstorm Watch in effect for south-central and
  southeastern Pennsylvania until 8 PM this evening.
* Increasing chance for some tornadoes across southeastern
  Pennsylvania this evening.

&&

.KEY MESSAGES...
1) Severe thunderstorms capable of damaging winds and heavy
rainfall remain possible today into this evening. An isolated
tornado will also be possible.

&&

.DISCUSSION...
KEY MESSAGE 1: Severe thunderstorms capable of damaging winds
and heavy rainfall remain possible today into this evening. An
isolated tornado will also be possible.

Current radar outlines a cluster of showers and thunderstorms
generally south of a FIG-UNV-AVP line, generally moving east-
southeastward as we move into the mid-afternoon hours. Some
breaks in the clouds during the late morning and early afternoon
hours has allowed for destabilization across this region, which
will allow for some severe potential throughout the rest of the
evening hours. Recent SPC Mesoanalysis maximized SBCAPE in the
1500-2000 J/kg range across southeastern Pennsylvania, which is
more than sufficient for some strong-to-severe thunderstorms in
the near-term. Shear remains the main question mark with regards
to a more organized severe threat with recent bulk shear values
topping out closer to 20 knots across south-central PA. Despite
this lack of shear, damaging winds will remain possible over
the next couple of hours and into the evening as more shear is
present closer to southeastern Pennsylvania. Of note, 0-1 km
shear on most recent SPC Mesoanalysis appears to be sufficient
for some tornadic potential as storms move further southeast
into slightly more favorable shear. In fact, the best storm (as
of 1PM EDT) across Huntingdon County did show some history of
rotation, and will be moving into a slightly more favorable
environment this afternoon. Given all these factors, Severe
Thunderstorm Watch will be in effect for portions of southern
and eastern Pennsylvania until 8PM this evening.

Heavy rainfall signal remains concerning for much of central
Pennsylvania with some gauge reports in Clearfield County and
Cambria County reporting fairly widespread 3-5" and have
prompted two Flash Flood Warnings this afternoon. HREF PWATs
near the 90th percentile will warrant some watching of areas
that receive either multiple rounds of thunderstorms and/or
slow-moving thunderstorms this evening. Overall, cells appear
that they will be moving, thus locations would ultimately need
to receive multiple rounds of this heavy rainfall in order for
problems to arise. That being said, instantaneous rainfall rates
between 2-4"/hr could cause some issues in the more urbanized
areas of southeastern Pennsylvania and the rolling hills of
south-central Pennsylvania where water will drain towards the
lowest locations. Thus, have expanded the Flood Watch a tier of
counties northward and eastward to grab the south-central
mountains to cover this threat.

Given the dual hydrology and severe threat this evening, have
multiple ways to receive warnings! If outdoors this afternoon
and evening, continue to monitor your local forecasts and have
plans in case a severe storms and/or flooding occurs. Some
storms will produce damaging winds and/or potentially a tornado
this afternoon/evening, while some will not. Flooding will also
be possible this evening given the ample rainfall rates, so if
you are located near smaller streams and/or urbanized areas, be
sure to monitor nearby surroundings if a thunderstorm moves over
your area.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Current forecast package will deal primarily with -SHRA and
TSRA moving across the forecast area through late evening. Very
moist atmosphere is currently producing MVFR to IFR conditions
in heavy rain and embedded TSRA. There is plenty of instabiity
but cloud cover from earlier has kept any of the storms from
becoming severe so far. This instability should be realized
into stronger storms over southern PA and would affect KMDT and
KLNS. Skies have cleared in this area and sun will help kick
start convection which will likely be severe by late afternoon.

Convection will wane later this evening as a cold front pushes
through the region. A result of the heavy rain will be a
lowering of conditions to MVFR and possible IFR in BR or FG.
Confidence is low to medium (20-40%) of any one location
dropping to LIFR at this time, so made a mention of a drop to
MVFR with VCFG wording overnight.

Behind the front on Wednesday, a BKN stratus layer will slowly
dissipate through the day on a breezy to gusty northwest wind.
Gusts will approach 20-25KTS during the afternoon.

Outlook...

Thu...Improving conditions with lingering -SHRA. Patchy AM fog.

Fri...Mainly VFR.

Sat and Sun...Patchy AM fog. Restrictions possible in isolated
showers/storms mainly in the south.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for PAZ026>028-035-036-
056>059-063>066.

&&

$$

WHAT HAS CHANGED...Beaty
KEY MESSAGES...Beaty
DISCUSSION...Beaty
AVIATION...Tyburski