-- Discussion containing changed information from previous version are highlighted. --
289
FXUS61 KPHI 241956
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
356 PM EDT Tue Jun 24 2025

.SYNOPSIS...
Our significant heat wave will continue through Wednesday as hot
high pressure remains centered over the Appalachians. The high will
will eventually weaken and allow a back door cold front to track
though much of the forecast area Thursday into Friday. The front
will then push back to the north as a warm front on Saturday and
Sunday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Significant and dangerous heat will continue through Wednesday. For
the remainder of the afternoon, we will see some of the hottest
temperatures in over a decade across some locales.

Temperatures will be a bit warmer compared to yesterday (mainly +1
to 2 degrees). At the same time, the pattern is favoring dewpoints
to mix out a bit (slightly lower humidity). But in the end, our heat
index values will not be very different compared to Monday. Like
yesterday, a sea-breeze has developed, but it`s not expected to move
too far inland.

There are no changes to our headlines through tomorrow. Extreme Heat
Warnings remain in effect for almost the entire area with the
exception of the coastal beach zones and Carbon and Monroe counties
where Heat Advisories are in place. Around the Delaware Valley,
Lehigh Valley, and northern New Jersey, overnight temperatures could
be the hottest observed in over a decade. There will be little
relief tonight as temperatures remain in the mid 70s to around 80,
likely even warmer in the most urban environments.

Heat tends to have cumulative effects on the body and is exacerbated
when the body can`t recover at night. If outside, drink water, take
frequent breaks, and find some shade. Watch out for heat cramps,
exhaustion, or stroke. Don`t leave people or pets in a closed car.
If air conditioning is not available in your home, find a cooling
option with friends or family or a nearby cooling station.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
With the ridge beginning to break down and a cold front
approaching from the north, a few showers and storms will be
possible (POPs around 20-40%) beginning later on Wednesday and
continuing into Wednesday night. With strong surface heating
earlier in the day enhancing low-level instability, gusty winds
could occur with any stronger storms, though marginal lapse
rates and weak winds aloft should temper any severe threat. With
the isolated showers and storms, increased cloud cover, and the
approaching cold front, Wednesday night will be slightly cooler
(though still quite warm). In general, lows are expected to be
near 70 in the Poconos and along the coast, and in the mid 70s
elsewhere.

Thursday, the ridge will continue to become further suppressed
and continue to shift south of the region as a backdoor cold
front crosses the region from the north during the morning and
eventually clearing the area Thursday evening.

Temperature-wise, areas north of the front will be noticeably
cooler with afternoon highs in the upper 70s to mid 80s. For
areas south of the cold front, high temperatures on Thursday
are expected to rise into the upper 80s and low 90s. For these
areas, it will remain humid, thus some heat indicies around
95-100 will be possible again, though with the faster
progression of the front, these look to be mainly contained to
Delmarva. By Thursday night, with the front through the area,
overnight lows will fall back into the mid 60s to around 70.

As the front crosses the region, scattered showers and storms
will become likely during the afternoon and evening hours.
Similar to Wednesday, marginal lapse rates and winds aloft will
limit severe potential, but isolated instances of gusty winds
could occur with the stronger storms.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
With the backdoor front south of the region on Friday and
prevailing onshore flow from the east to east-northeast, we will
get to enjoy a dramatically cooler day with cloudy skies and
highs only in the upper 60s to upper 70s! A few showers and
perhaps a thunderstorm will be possible as well through the day.
Overnight lows will be cool and in the 60s.

Southwesterly flow returns for the weekend with the backdoor
front retreating northward as a warm front Saturday morning and
high pressure over the southeast shifting offshore. As a
result, temperatures will begin to warm back closer to
climatology over the weekend and slightly above into the new
week. Isolated, primarily diurnally driven convection, will be
possible each day. A more active weather pattern may begin to
take shape Tuesday and beyond, with indications of a slightly
more amplified upper- air pattern taking shape.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...VFR. W to NW winds 5 kt or less. High confidence.

Wednesday...Mainly VFR. Can`t rule out a shower/thunderstorm in the
afternoon along with brief sub-VFR conditions. But any convection
will be isolated. High confidence.

Outlook...

Wednesday night through Sunday...Mainly VFR. Brief periods of
sub- VFR will be possible during the afternoon and evening hours
each day in isolated to widely scattered showers and storms.

&&

.MARINE...
-- Changed Discussion --
Tonight...Sub-SCA conditions expected. W to NW winds 10 kts or less.
Seas around 2 feet.

Wednesday...Sub-SCA conditions expected. NW winds 10 kts or less in
morning becoming SE around 10 kts in the afternoon. Seas around 2
feet.

Outlook...

Wednesday night through Sunday...No marine headlines expected.
Periods of showers and storms possible each day, but
significant marine impacts are not anticipated.

Rip Currents...

For Wednesday, winds will be light out of the south at 5 to 10 mph
or less. Waves in the surf zone will be around 1 to 2 feet with a
dominant swell around 8 seconds. This set up will result in a LOW
risk for the development of dangerous rip currents for both the
Jersey shore and the Delaware Beaches.

For Thursday, winds will turn more onshore out of the east at 10 to
15 mph with waves continuing to be around 1 to 2 feet with a
dominant swell around 8 seconds. This set up with an onshore flow
will result in a MODERATE risk for the development of dangerous rip
currents for shore areas in Monmouth County NJ with a LOW risk
continuing for the rest of the Jersey shore and the Delaware
Beaches.

For specific beach forecasts, visit weather.gov/beach/phi
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
With the New Moon approaching tomorrow, June 25th, astronomical
tides are increasing. Spotty minor tidal flooding was observed
for the immediate coastline and back bays as well as within
Delaware Bay last night. Expecting this to continue with the
evening high tide for the next two nights and it`s possible for
tomorrow evening`s high tide that some Advisories may end up
being needed.

Higher confidence in advisories potentially being needed starting
Thursday evening. While we get away from the New Moon, onshore flow
will result in water piling up and more widespread minor tidal
flooding for the coastal and Delaware Bay communities.

No tidal flooding is expected within the tidal Delaware River or
Chesapeake Bay.

&&

.CLIMATE...
-- Changed Discussion --
Near record breaking heat is expected across the area through
the middle of the week. All climate sites except Wilmington and
Georgetown set record highs and all climate sites except
Reading set record warmest low temperatures for June 23rd.

Additionally, Mount Pocono set their all-time record high
temperature for June yesterday (June 23rd). The Atlantic City
Marina and Wilmington tied their all time record warmest low
temperature for June yesterday (June 23rd) as well. Further
records are expected to fall into the week. Below is a look at
the last 100 degree day, daily record high maximum and minimum
temperature for all of our climate sites.

Most Recent 100 Degree Day

Site                              Date/Temperature
Allentown (ABE)          July 22, 2011/104
AC Airport (ACY)         July 21, 2019/100
AC Marina (55N)          July  5, 1999/101
Georgetown (GED)         July 21, 2019/100
Mount Pocono (MPO)       July  3, 1911/103
Philadelphia (PHL)       July 18, 2012/100
Reading (RDG)            June 22, 2024/101
Trenton (TTN)            July 18, 2012/100
Wilmington (ILG)         July 18, 2012/101

Record High Temperatures
                          June 24
Site                  Record/Year
Allentown (ABE)           98/1923
AC Airport (ACY)          99/2010
AC Marina (55N)           95/2002
Georgetown (GED)          97/2010
Mount Pocono (MPO)        92/1914
Philadelphia (PHL)        99/1923
Reading (RDG)             98/1908 & 1923
Trenton (TTN)             98/1894
Wilmington (ILG)         102/1894

Record Warmest Low Temperatures
                          June 24
Site                  Record/Year
Allentown (ABE)           71/2010
AC Airport (ACY)          72/1951, 2013, 2017 & 2024
AC Marina (55N)           72/1924, 2002, 2010, 2011, 2013 & 2020
Georgetown (GED)          74/2010
Mount Pocono (MPO)        66/1960, 1964 & 2002
Philadelphia (PHL)        75/1909, 1921, 1994 & 2020
Reading (RDG)             73/1909, 1994 & 2010
Trenton (TTN)             76/1894 & 2010
Wilmington (ILG)          74/1994

Record High Temperatures
                          June 25
Site                  Record/Year
Allentown (ABE)           98/1923
AC Airport (ACY)          96/1997
AC Marina (55N)           95/1952
Georgetown (GED)          96/1952
Mount Pocono (MPO)        91/1952
Philadelphia (PHL)        98/1952
Reading (RDG)             99/1943
Trenton (TTN)             99/1997
Wilmington (ILG)          98/1894

Record Warmest Low Temperatures
                          June 25
Site                  Record/Year
Allentown (ABE)           74/1923 & 1976
AC Airport (ACY)          80/1950
AC Marina (55N)           75/1997 & 2002
Georgetown (GED)          75/2019
Mount Pocono (MPO)        69/1952
Philadelphia (PHL)        76/1909, 1976 & 2002
Reading (RDG)             75/1943 & 1949
Trenton (TTN)             75/1976
Wilmington (ILG)          75/1976
-- End Changed Discussion --

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Extreme Heat Warning until 8 PM EDT Wednesday for PAZ060>062-
     070-071-101>106.
     Heat Advisory until 8 PM EDT Wednesday for PAZ054-055.
     Air Quality Alert until midnight EDT tonight for PAZ070-071-
     101>106.
NJ...Extreme Heat Warning until 8 PM EDT Wednesday for NJZ001-
     007>010-012-013-015>023-027.
     Heat Advisory until 8 PM EDT Wednesday for NJZ014-024>026.
     Air Quality Alert until midnight EDT tonight for NJZ012>027.
DE...Extreme Heat Warning until 8 PM EDT Wednesday for DEZ001>003.
     Heat Advisory until 8 PM EDT Wednesday for DEZ004.
MD...Extreme Heat Warning until 8 PM EDT Wednesday for MDZ012-015-
     019-020.
MARINE...None.

&&

$$

SYNOPSIS...Kruzdlo
NEAR TERM...Hoeflich/Kruzdlo
SHORT TERM...AKL/Cooper/MJL
LONG TERM...AKL/Cooper/MJL
AVIATION...AKL/Kruzdlo
MARINE...AKL/Fitzsimmons/Kruzdlo
TIDES/COASTAL FLOODING...
CLIMATE...