585
FXUS61 KCTP 110210
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1010 PM EDT Wed Jun 10 2026

.WHAT HAS CHANGED...
Heat Advisory issued for Lancaster, York, Adams, Cumberland,
Dauphin, and Lebanon Counties for Thursday and Friday.

&&

.KEY MESSAGES...
1) Increasing heat and humidity will bring increased risk for
heat-related illnesses Thursday, and especially on Friday.

2) Daily shower and thunderstorm chances continue through the
end of the work week. Some strong to severe thunder with
damaging winds possible.

3) A refreshing decrease in humidity is a good bet this weekend
with high pressure moving in after a cold front.

&&

.DISCUSSION...
KEY MESSAGE 1: Increasing heat and humidity will bring
increased risk for heat-related illnesses Thursday, and
especially on Friday.

With an upper level ridge in place advecting in a very warm to
hot airmass, heat and humidity will continue to build for
Thursday and Friday, particularly for the eastern two thirds of
the forecast area. High levels of humidity tonight, as well as
recent rainfall, will result in patchy fog tonight into early
Thursday morning.

There is quite a bit of uncertainty remaining in how high the
temperatures and heat index values get due to variable cloud
cover and the potential for showers and thunderstorms both days
(especially Friday). The continued thinking is that the NBM is a
bit too high with both temperatures and dew points both days,
especially given the recent high bias. Therefore, similar to
previous forecast cycles, went a few degrees cooler than the
NBM.

All of this being said, the forecast heat index for Thursday
and Friday still get to the upper 90s and low 100s for the
southeastern portions of the area on Thursday, particularly the
Harrisburg/Lancaster/York areas. Heat Advisories have been
issued for Lancaster, York, Adams, Cumberland, Dauphin, and
Lebanon Counties for Thursday and Friday. We will continue to
evaluate the potential for expanding the advisory either day.

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

KEY MESSAGE 2: Daily shower and thunderstorm chances continue
through the end of the work week. Some strong to severe thunder
with damaging winds possible.

Underneath a broad ridge of high pressure, a couple shortwaves
will drift across Pennsylvania over the next few days.
Sufficient instability in the presence of warm & moist air along
with variable amounts of shear will lead to multiple rounds of
showers and thunderstorms tonight through Friday. This will be
a typical summerlike pattern with many storms on radar and
lingering questions about how strong they`ll get. If multicell
clusters can develop large enough cold pools, an elevated threat
of damaging wind gusts may materialize in the form of an MCS.
Such a scenario cloud produce a swath of more significant wind
damage (most likely on Thursday).

A cold frontal passage will occur on Friday. An approaching upper
trough and high available moisture suggest severe thunderstorms
are possible. But, the small ridge that pumps up overhead late
Thu could be a setback for how widespread the threat will be.

The biggest question is timing/speed of the cold front. A
faster progression could mean the cold front clears our area
before peak heating (lower threat of damaging winds), while a
later arrival could spell more concern for severe weather.

The repeated shots of scattered to numerous SHRA/TSRA over the
next 2 days is likely to yield lower FFG thresholds and some
flash flooding would become possible, too. But, it has been very
dry recently, and everything is growing and thirsty, ready to
soak up as much as it can. As always, too much of a good thing
can be bad. We`ll keep an eye on the soil saturation and other
factors that could lead to flooding.

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

KEY MESSAGE 3: A refreshing decrease in humidity is a good bet
this weekend with high pressure moving in after a cold front.

Following the passage of the aforementioned cold front, much
more comfortable conditions will arrive on Saturday and Sunday.
Temperatures will remain warm (highs in the 80s and even some
lower 90s on Sunday), but dew points will be much lower (in the
50s and lower 60s, instead of the 70s). Then, cooler
temperatures arrive by Monday with highs in the 70s to lower
80s. This will be due to another cold front passage on Sunday,
which will bring a renewed chance for showers and
thunderstorms.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
As of 00Z, some isolated showers tapering off remain after the
main storms moved out of the region. A cluster of showers and
thunderstorms north of Pittsburgh may allow for some
convective restrictions in the next 6 hours as they move
westward. This solution is most likely at JST and AOO but
uncertainty remains on how much coverage they will occupy. Some
other overnight convective activity is possible across Central
PA but confidence remains low in exact impacts/timing. Something
to watch tomorrow will be for multiple rounds of showers and
thunderstorms to impact the region. Model guidance depicts an
unstable environment with minimal inhibition through the day as
multiple shortwave impulses move through the region. As a
result, an early round of showers and thunderstorms (12Z-17Z)
may develop in addition to later afternoon/evening (20Z-00Z)
convective activity. With such a moist airmass in place,
visibility restrictions and gusty winds within these showers and
thunderstorms are likely.

As for ceilings, BFD is most likely to see IFR ceilings tonight.
Prevailing MVFR and low VFR are possible at JST, BFD, UNV, and
IPT with the moist airmass lingering. Prevailing visibility
restrictions are most likely at IPT, but confidence in <3SM is
highest east of the airport at this time. VFR looks to prevail
tomorrow, however as mentioned before, multiple rounds of
convection may lead to restrictions and lightning.

Outlook...

Thursday afternoon...Restrictions possible in scattered
-SHRA/-TSRA.

Friday...Restrictions expected as FROPA brings line of -TSRA.

Saturday...Mainly VFR.

Sunday...VFR favored early, with restrictions possible as FROPA
brings chance of -SHRA/-TSRA later in the day.

Monday...Additional scattered -SHRA and associated restrictions
possible.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM Thursday to 8 PM EDT Friday for
PAZ057-059-063>066.

&&

$$

WHAT HAS CHANGED...Colbert
KEY MESSAGES...Banghoff/Colbert
DISCUSSION...Banghoff/Colbert
AVIATION...Lambrech