Special Marine Warning 85, NWS Philadelphia/Mount Holly

Area Forecast Discussion
National Weather Service Mount Holly NJ
347 PM EDT Wed Jul 15 2026

.WHAT HAS CHANGED...
Chances for showers and storms have decreased some for Sunday.

&&

.KEY MESSAGES...
1. Above normal temperatures will continue through Thursday. Extreme
Heat Warnings and Heat Advisories are in effect for our entire
forecast area for today, possibly into Thursday.

2. A cold front will pass through the region this evening. Isolated
thunderstorms will be possible late in the afternoon and early
evening.

3. Smoke from Canadian wildfires will infiltrate the area beginning
tonight through Thursday, and potentially lingering through Friday
into Saturday.

4. The first half of the weekend is shaping up to be active and
unsettled with showers and thunderstorms expected for Saturday into
Saturday night. Some of these could be severe and also produce
heavy rainfall resulting in flash flooding.

&&

.DISCUSSION...
KEY MESSAGE 1...Above normal temperatures will continue through
Thursday. Extreme Heat Warnings and Heat Advisories are in effect
for our entire forecast area for today, possibly into Thursday.

Heat and humidity will peak today as strong upper ridging remains in
place. A low pressure system moving through eastern Canada will
result in warm advection amid westerly flow.

High temperatures today are expected to top out in the mid 90s to
near 100 degrees in most areas with dew points in the upper 60s to
mid 70s. This will result in heat indicies in the 100-109 degree
range for most of the area, hottest along and southeast of I-95. A
modest westerly wind near 10-20 mph help keep the sea breeze from
making any inland progress during the afternoon hours, keeping
coastal areas quite warm as well.

A weak cold front will pass through the area tonight, which will
knock down both temperatures and dew points a bit for Thursday.
While it will still be quite hot, with highs in the 90s, heat
indicies will only be a few degrees higher from the actual air
temperature. Also, have to consider how thick the smoke will be in
the area (see more on that below), which may limit daytime heating
on Thursday. This could result in temperatures being several degrees
cooler than what is currently forecast. Considering this and upon
discussion with neighboring offices, have opted to hold off on any
Heat Advisories for Thursday and see how much of an impact smoke
aloft will have on temperatures.

KEY MESSAGE 2...A cold front will pass through the region late this
afternoon into tonight. Isolated thunderstorms will be possible late
in the afternoon and early evening.

Most of today is still expected to be dry, however, there remains a
threat for isolated thunderstorms across the northern half of the
area during the late afternoon into the evening hours. A shortwave
will move across portions of New England, only scraping our area,
however, H5 flow on the order of 50-55 kt will overspread the area.
The environment during the afternoon and early evening hours ahead
of the cold front will become strongly unstable, with SBCAPE values
of 2000-2500 J/kg. Low-level lapse rates will be steep, with 0-3 km
lapse rates near dry adiabatic. Mid-level dry air from subsidence
will contribute to very high DCAPE values around 1200-1500 J/kg.
With the enhanced mid-level flow overspreading the region, effective
shear will range from 40-50 kt, greatest across northern portions of
the area. All of this being said, the environment in place will be
conditionally supportive of severe winds and some isolated large
hail, if and only if, any storms are able to develop.

For this reason, PoPs largely remain around 20-30% for areas north
of the PA Turnpike and I-195 in New Jersey. Elsewhere, PoPs are 10%
or less. Any storms that develop should track southeast into the
evening hours before diminishing with the loss of diurnal heating.

KEY MESSAGE 3...Smoke from Canadian wildfires will infiltrate the
area beginning tonight through Thursday, and potentially lingering
through Friday into Saturday.

The latest hi-res guidance continues to indicate near surface smoke
the wildfires in western Ontario will spread into the region
following tonight's cold frontal passage. The smoke appears likely
to persist in the area through Thursday night, and potentially
lingering through Friday and Saturday as well. The smoke is
anticipated to result in visibility restrictions and potential for
poor air quality, but exactly to what degree this may be is
uncertain. This smoke event is not currently anticipated to be as
severe as the June 2023 event, but this will be difficult to predict
ahead of time.

For more information about air quality in your area, visit your
state Department of Environmental Protection agency. We will also
relay any Air Quality Alerts they may issue on our website.

KEY MESSAGE 4...The first half of the weekend is shaping up to be
active and unsettled with showers and thunderstorms expected for
Saturday into Saturday night. Some of these could be severe and also
produce heavy rainfall resulting in flash flooding.

We are still a few days out, but are monitoring the potential flash
flooding and severe weather setup as we get into the weekend.

As we get towards Friday night, low pressure will be approaching as
it moves into the Great Lakes region and pushes a warm front ahead
of it northwards towards the area. This could bring some showers and
storms into the area as early as the overnight period Friday night
with more widespread showers and storms expected for Saturday into
Saturday night as low pressure moves from the lower Great Lakes
eastward towards New England. As is often the case with these summer
patterns, there is some potential for both severe weather and heavy
rain/flash flooding. At this vantage point the shear looks to be
moderate to potentially strong with the main question being how
unstable it will get. This will determine the extent of any severe
weather threat but at this point we see at least some potential for
severe weather Saturday...especially during the afternoon and
evening. Precipitable water values will also be increasing to around
2+ inches. That is well above the 90th percentile for this time of
year, increasing the risk for heavy rain/flash flooding. It appears
storms may come through in multiple rounds with one or more rounds
of storms coming in later Friday night into the day Saturday with
the warm front and then another coming in late day into Saturday
night ahead of the cold front. So the bottom line is that Saturday
could be quite unsettled and most of the region has POPs in the 70-
90 percent range reflecting this.

As we head towards the latter part of the weekend, the latest
indications are for the cold front to move through a little faster
Saturday night into early Sunday. This will keep some chances for
showers/storms around into the first part of Sunday but but based on
this faster timing of the front, it looks like we will start to
clear out from NW to SE by the latter part of Sunday. As such, the
threat for severe weather and/or flash flooding appears low at this
time for Sunday.

High pressure builds in to start the new week before the next
frontal system may affect the area next Tuesday into Wednesday with
renewed chances for showers and storms.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Rest of Today...Primarily VFR. Wildfire smoke is expected to remain
north of all terminals through the rest of today, with the exception
of ABE which may see some hazy skies after 21Z. Also, isolated
showers or storms are possible at ABE late as well, so have included
a PROB30 group there. West-south west winds around 10-15 kt with
gusts up to 20 kt. High confidence overall.

Tonight...Any VFR conditions to start will lower to MVFR between 00-
05Z from north to south. MVFR visibilities from wildfire smoke will
prevail through the remainder of the overnight. West winds around 5-
10 kt early in the evening will become north-northwest overnight
around 5 kt or less. Moderate confidence overall.

Thursday...MVFR visibilities will likely continue through much of
Thursday from wildfire smoke. There are indications that some denser
smoke will arrive later in the day (which may cause IFR visibilities
at times), but this primarily looks to hold off until Thursday
night. West-southwest winds around 10-15 kt with gusts up to 20 kt
in the afternoon. Moderate confidence overall.

Outlook...

Friday...Some restrictions possible due to lingering smoke from the
Canadian wildfires

Saturday through Saturday night...At least some restrictions likely
at times due to showers and storms.

Sunday...Lingering showers/storms possible in the morning then
becoming mainly VFR by the afternoon.

Monday...VFR expected.

&&

.MARINE...
No marine headlines are in effect through Thursday. Southwest winds
around 10-15 kt through this evening will become north-northest
overnight around 5-10 kt following a frontal passage. Winds will
then become south-southwest again on Thursday around 10-15 kt. Seas
around 2-3 feet through Thursday.

Generally fair weather is expected, however wildfire smoke will
filter into the region tonight into Thursday. This may cause some
localized areas of visibility restrictions, however no marine dense
smoke advisories for this are warranted at this time.

Outlook...

Friday...Canadian wildfire smoke may cause visibility restrictions
at times. Otherwise, fair weather and no marine hazards anticipated.

Saturday through Saturday night...South to southwesterly winds could
approach advisory criteria, with 10-15 kt winds and gusts 20-25 kt.
Seas generally under 5 feet. Showers and thunderstorms likely. Smoke
may also linger some during this period potentially still causing
some visibility restrictions.

Sunday...No marine hazards currently anticipated with winds under 25
kts and seas under 5 feet. Scattered showers and thunderstorms
possible.

Monday...Fair weather expected with winds under 25 knots and seas
around 3 feet.

Rip Currents...

On Thursday, south to southwest winds will average 10 to 15 mph
with a light southeast swell with a period of 6 to 8 seconds.
Breaking waves will average 1 to 2 feet. As a result, there is a
LOW risk for the development of dangerous and life threatening
rip currents at the Jersey Shore and at Delaware Beaches.

On Friday, north winds around 10 mph in the morning will veer to
the southeast in the afternoon with a light southerly swell
with a period around 6 seconds. Breaking waves will average 1
to 2 feet. As a result, there is a LOW risk for the development
of dangerous and life threatening rip currents at the Jersey
Shore and at Delaware Beaches.

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

&&

.CLIMATE...
A brief 1-day spike in temperatures is expected today, with
highs likely to approach records. Here are the records for
Wednesday, July 15:

Allentown/ABE      98 in 1995
AC Airport/ACY    100 in 1995
AC Marina/55N      99 in 1995
Georgetown/GED     96 in 2024 and 1993
Mount Pocono/MPO   92 in 1954
Philadelphia/PHL  103 in 1995
Reading/RDG       100 in 1995
Trenton/TTN       101 in 1995
Wilmington/ILG     99 in 1997 and 1995

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Extreme Heat Warning until 8 PM EDT this evening for PAZ070-
     071-104-106.
     Heat Advisory until 8 PM EDT this evening for PAZ054-055-
     060>062-101>103-105.
NJ...Extreme Heat Warning until 8 PM EDT this evening for NJZ010-
     012>015-017>020-027.
     Heat Advisory until 8 PM EDT this evening for NJZ001-007>009-
     016-021>026.
     Air Quality Alert until midnight EDT tonight for NJZ001-
     007>010.
DE...Extreme Heat Warning until 8 PM EDT this evening for DEZ001.
     Heat Advisory until 8 PM EDT this evening for DEZ002>004.
MD...Heat Advisory until 8 PM EDT this evening for MDZ012-015-019-
     020.
MARINE...None.

&&

DISCUSSION...Cooper/DeSilva/Fitzsimmons/Johnson/Staarmann
AVIATION...DeSilva/Fitzsimmons/Staarmann
MARINE...DeSilva/Fitzsimmons/MPS/Staarmann

Hazardous Weather Outlook
National Weather Service Mount Holly NJ
515 AM EDT Wed Jul 15 2026

MDZ012-015-019-020-160915-
Kent MD-Queen Annes-Talbot-Caroline-
515 AM EDT Wed Jul 15 2026

...HEAT ADVISORY REMAINS IN EFFECT FROM 10 AM THIS MORNING TO 8 PM
EDT THIS EVENING...

This Hazardous Weather Outlook is for northeast Maryland.

.DAY ONE...Today and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Heat Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Hot and humid conditions are forecast for Thursday, with heat indices
up to 105 degrees possible. Severe thunderstorms will be possible
Saturday and Sunday.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to standard operating procedures.

Staarmann