Damaging Winds in Pennsylvania, June 11, 2026

Area Forecast Discussion
National Weather Service Mount Holly NJ
726 PM EDT Thu Jun 11 2026

.WHAT HAS CHANGED...
Severe Thunderstorm Watch 317 is now in effect for the entire
area until midnight tonight.

The severe weather threat has trended a bit later for today.
There is also the potential for severe weather on Sunday.

Updated the key message for tidal flooding and updated the rip
current forecast for Friday and Saturday.

&&

.KEY MESSAGES...
1. There is a risk of severe thunderstorms today and Friday.

2. Dangerous heat (potentially record heat) and humidity for much of
the region through Friday, then much less humid over the
weekend.

3. Chances for showers and storms will return as a cold front passes
through late Sunday into Sunday night, then turning more seasonable
through the middle of next week.

4. Widespread minor coastal flooding will develop with the evening
high tide cycles Saturday and Sunday along the Atlantic coast,
Delaware Bay, and on the tidal Delaware River and its
tributaries.

&&

.DISCUSSION...
KEY MESSAGE 1...There is a risk of severe thunderstorms today
and Friday.

Severe Thunderstorm Watch 317 is now in effect for the entire
area until midnight tonight.

The pattern in place will continue to support some additional
showers and thunderstorms across the region today and Friday,
mainly during each late afternoon to evening period. Better
synoptic forcing will arrive Friday with a cold front.

For today's severe weather threat, the larger scale forcing and
shear are expected to remain relatively weak. A shortwave moving out
of the lower Great Lakes region will help trigger shower and
thunderstorm development. One change through the day with recent
guidance has been a later arrival of the convection. The general
timing for severe weather for our area is mainly 6 PM to midnight
tonight from west to east. In terms of the atmospheric environment,
shear values are weak, but there is plenty of instability with the
hot and humid conditions that are present. These conditions will
also allow for supportive lapse rates. This afternoon, convection is
already blossoming across western portions of PA with this scattered
activity expected to congeal into a broken line that arrives
through the evening hours.

A SLIGHT risk (level 2 out of 5) for a severe thunderstorm potential
remains in place for today. Damaging winds will be the main threat
as storms may cluster or evolve into one or more broken lines with
some bowing, however large hail cannot be ruled out given the
magnitude of the instability that is forecast.

Tomorrow, the region is expected to begin feeling the influence of
the upper-level trough to the west of the region, in addition to a
cold front that will be arriving from the west. Some showers and
thunderstorms should focus near and ahead of this front, and with
strong destabilization and slightly better wind fields aloft, a
severe threat will once again be present. The convective coverage
could be once again enhanced by a convectively induced shortwave
from near the Great Lakes or upper Ohio Valley. This evolution is
less certain, however our entire area is highlighted in a SLIGHT
risk (level 2 out of 5) for severe thunderstorms. Damaging winds
will once again be the main threat as storms may tend to cluster or
evolve into one or more short lines with some bowing.

KEY MESSAGE 2...Dangerous heat (potentially record heat) and
humidity for much of the region through Friday, then much less
humid over the weekend.

A mid-level ridge slides across the Mid-Atlantic and Northeast
through Friday. At the surface, high pressure remains centered
off the Southeast U.S. coast which will continue to direct a hot
and humid airmass across our area.

Dangerous heat is expected across much of our region through
Friday, with even some record high temperatures potentially
getting challenged. High temperatures both today and Friday are
forecast to peak into the low to mid 90s across most of the
area, though highs may be slightly warmer Friday compared to
today. Dewpoints will start out in the low to mid 70s, but with
afternoon heating and mixing, these should mix down to the upper
60s and low 70s. This still results in peak heat index values
of 95 to 105 degrees across the majority of the area, outside of
the southern Poconos. This level of heat and humidity can
become dangerous quickly for sensitive individuals and those
outdoors for extended periods of time. A Heat Advisory remains
in effect through Friday for areas where the heat index criteria
starts at 96F and 100F.

A cold front is forecast to move through the region late Friday,
which will knock the temperatures and especially the dewpoints
down several degrees. Though it will still be hot with high
temperatures in the upper 80s to low 90s over the weekend,
dewpoints will return to much more comfortable levels (into the
50s in some areas Saturday) and this minimizes the risk for
additional heat related advisories.

KEY MESSAGE 3...Chances for showers and storms will return as a cold
front passes through late Sunday into Sunday night, then turning
more seasonable through the middle of next week.

A shortwave trough will push another cold front through the region
late Sunday into Sunday night. This will give us another round of
scattered showers and thunderstorms, however this one will be
different than the activity we're experiencing this week. There
looks to be plenty of synoptic forcing with more shear present.
Also, there will be instability and supportive lapse rates.
Timing variations remain among guidance for the cold front, but
the atmospheric conditions are supportive of convection during
the afternoon and evening hours. Given these atmospheric
conditions, the Storm Prediction Center has outlooked us for
severe weather Sunday, particularly during the afternoon and
evening hours. PWAT values will also recover for Sunday allowing
for some heavy rain with the convective activity.

The frontal passage will usher in a much more seasonable airmass
that will stick around through at least the middle of next week.
Highs will be in the upper 70s to mid 80s Monday through Wednesday,
with lows in the mid 50s to low 60s. Dewpoints in the 50s and low
60s will make for much more pleasant conditions. Can't completely
rule out a few showers, but overall the chances for rain look low
during this period.

KEY MESSAGE 4...Widespread minor coastal flooding will develop with
the evening high tide cycles Saturday and Sunday along the Atlantic
coast, Delaware Bay, and on the tidal Delaware River and its
tributaries.

A New Moon this weekend will result in higher than normal
astronomical tides. Astronomical tides will generally be 1/2 foot
less than minor coastal flooding thresholds, and tidal departure s
will be around 1 foot or so. This will result in widespread minor
coastal flooding with the evening and nighttime high tide cycles
Saturday and Sunday on the Atlantic coast, Delaware Bay, and the
tidal Delaware River and its tributaries. The higher of the two will
be Sunday night. Tidal flooding is not currently expected along the
eastern shore of Chesapeake Bay.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...Scattered showers and thunderstorms should end by
04-06Z everywhere, likely resulting in some restrictions, then
VFR. Cannot rule out some patchy fog late. West to southwest
winds 5 kts or less. Moderate confidence.

Friday...Prevailing VFR expected through the period. Brief
restrictions are possible, with scattered showers and
thunderstorms, most likely after 18-21Z. High confidence in
prevailing VFR through the day, moderate confidence in thunder
timing.

Outlook...

Friday night...Sub-VFR possible with a chance for lingering
showers and storms.

Saturday...VFR. No significant weather expected.

Sunday...Restrictions possible with the chance for showers and
storms.

Monday...VFR. No significant weather expected.

Tuesday...Restrictions possible with the chance for showers and
storms.

&&

.MARINE...
No prevailing marine hazards expected through Friday. A
southwest wind at 10 kt with gusts 15-20 kt and seas of 3-4
feet. Showers and thunderstorms may impact the nearshore waters
and Delaware Bay during this evening and again Friday evening,
with brief strong wind gusts possible.

Outlook...

Saturday...No marine hazards anticipated. Winds will generally
remain between 5-15 kt. Seas generally around 2-3 feet. Fair
weather expected.

Sunday...A brief period of marginal Small Craft Advisory
conditions are possible Sunday afternoon and evening with wind
gusts near 25 kt.

Monday and Tuesday...No marine hazards anticipated with winds
5-10 kt and seas 2-3 feet.

Rip Currents...

For Friday, a medium period 8 second swell, offshore winds, and
breaking waves 2 feet or less will result in a LOW risk for
development of rip currents at the Jersey Shore and Delaware
Beaches.

On Saturday, conditions will be relatively similar, though the
dominant period will increase to around 10 to 11 seconds.
However, with winds offshore, and breaking waves again 2 feet or
less, there will not be much energy in the surf zones. This will
result in another day of a LOW risk for the development of rip
currents.

Ocean water temperatures are mostly in the mid to upper 60s.

For specific beach forecasts, visit weather.gov/beach/phi

&&

.CLIMATE...
A very hot and humid airmass will overspread our area through
Friday. Some record high and warmest low temperatures could be
challenged Thursday and/or Friday.

Location                   6/11 Record Highs/Year

Mount Pocono                  91/1911
Allentown                     94/1984
Reading                       98/1911
Philadelphia                  95/1986
Trenton                       96/1911
Atlantic City Airport         97/1984
Atlantic City Marina          91/1959
Wilmington                    95/1973
Georgetown                    95/1947 & 1959

Location                   6/12 Record Warmest Low/Year

Mount Pocono                  69/2005
Allentown                     70/1942
Reading                       75/1958
Philadelphia                  75/2015
Trenton                       72/2015 & 2017
Atlantic City Airport         73/1973 & 2015
Atlantic City Marina          79/2016
Wilmington                    73/2015
Georgetown                    73/1947, 1973, 1986, & 2017

Location                   6/12 Record Highs/Year

Mount Pocono                  87/1967
Allentown                     92/1949, 1961, 2015, & 2017
Reading                       95/1984
Philadelphia                  95/1947 & 2015
Trenton                       94/1933
Atlantic City Airport         94/2017
Atlantic City Marina          93/1880 & 1914
Wilmington                    96/1933
Georgetown                    95/2017

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Heat Advisory until 8 PM EDT Friday for PAZ060>062-070-071-
     101>106.
NJ...Heat Advisory until 8 PM EDT Friday for NJZ001-007>010-012>015-
     017>020-027.
DE...Heat Advisory until 8 PM EDT Friday for DEZ001.
MD...None.
MARINE...None.

&&

DISCUSSION...Guzzo/MJL/MPS/Staarmann
AVIATION...AKL/MJL
MARINE...AKL/Hoeflich