982
FXUS61 KPHI 101025
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
625 AM EDT Sun Aug 10 2025

.SYNOPSIS...
High pressure extending across our area will gradually weaken and
shift east through Tuesday. A surface trough looks to become
established across our area Wednesday into Thursday, then a cold
front settles in from the northwest Thursday into Friday. This
front may then stall near our area over the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Some patchy fog across the Delmarva and southern NJ early this
morning will lingering for an hour or two after daybreak before
mixing out.

Another beautiful August day on tap Sunday to close out a
spectacular weekend weather-wise. While the surface high offshore
moves further out to sea, upper level ridging will encourage a
secondary surface high to develop almost squarely overhead this
morning before slowly shifting towards the coast. As a result, we
will see sunny skies and a very light southeast wind. The loss of
our northeast flow from the past few days will allow for
temperatures to warm a few degrees, but not by much. Afternoon highs
will only be a few degrees warmer than Saturday with mid to upper
80s for most, very close to climatology for most. Areas along the
shore and across the higher elevations will remain cool in the upper
70s to low 80s. Humidity will remain low as well with dew points
still expected to be in the mid 50s to around 60.

Sunday night will see calm winds and mostly clear skies, helping us
radiate once again. Lows will be in the upper 50s to mid 60s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Few changes in the short term. Expecting continued tranquil
conditions as the surface high remains the dominant feature. It
will however gradually weaken and shift further east. A mid and
upper level shortwave ridge builds over the Northeast into
Monday before weakening on Tuesday. The net result of this is a
gradual warming trend. High temperatures both days are forecast
to be in the 80s to low 90s. Dew points are forecast to be in
the 50s and 60s (except low 70s in Delmarva on Tuesday).
Consequently, it appears heat indices remain safely below Heat
Advisory criteria. Some fog is possible however mainly later
Monday night into Tuesday morning given somewhat higher dew
points combined with decent radiational cooling.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Summary...Starting with very warm and humid conditions. There
are two periods with chances for showers and thunderstorms.

Overall, not too many changes in this period, though individual
deterministic models depict some differences in the timing of
the mid week system and the late week cold front.

Synoptic Overview...An upper-level trough should slide across the
northeastern U.S. Wednesday or Thursday. Most models show it low
amplitude, meaning that it will be mostly north of our region.
At the surface, a trough is forecast to be in place across our
area Wednesday into Thursday, then a cold front settles in from
the northwest Thursday. This front may then stall near our area
over the weekend.

For Wednesday and Thursday...As an upper-level trough makes its way
eastward across southeastern Canada to New England, it is forecast
to glance our area. A surface trough looks to be across or near our
area during this time, serving as a focus for low level
convergence and convective initiation. This may then spread
eastward into the evening before weakening some. A cold front
looks to arrive across our area Thursday and with a moist and
very warm air mass in place should result in some convection.
The coverage and intensity of this is less certain given the
passage of the upper- level trough well to our north. Both days
appear to be warm and humid with highs in the 80s to lower 90s,
and dewpoints getting near 70 degrees. This could lead to heat
index values near 100, but will continue to watch trends closely
as we get closer to this period.

For Friday and Saturday...Weak mid level ridging is forecast to
arrive during this time frame from the south. This may position
surface high pressure to our north and northeast, which would
help push the cold front to our south. The air mass may cool
some and this will depend on how far south the front gets and
the influence of a surface high to our north and northeast. Some
chances for convection both days, however this will depend on
the positioning of the front and where a possible convergence
area sets up between the aforementioned surface high and a warm
front in the upper Ohio Valley.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Sunday...VFR. Winds pick up out of the south/southeast around 5-10
kt. High confidence.

Sunday night...Prevailing VFR. High confidence.

Outlook...

Monday and Tuesday...Some local fog possible mostly later
Monday night into Tuesday morning, otherwise VFR.

Wednesday and Thursday...Some showers and thunderstorms possible,
especially each afternoon and evening with local sub-VFR conditions,
otherwise VFR.

&&

.MARINE...
Sub-SCA conditions through Sunday night. Light northeast winds shift
to the southeast 5-10 kts by the afternoon, becoming more light and
variable at night. Seas 2 to 4 feet early, becoming 2 to 3 feet by
Sunday night.

Outlook...

Monday through Thursday...The conditions are anticipated to be
below Small Craft Advisory criteria.

Rip Currents...

For today, northeast wind in the morning will become southeast
around 5-10 mph this afternoon. Breaking wave heights 2-3 feet.
Easterly swell around 3 feet at 7-8 seconds in length. Given
these factors, as well as the recent full moon, A MODERATE risk
for the development of dangerous rip currents at all beaches has
been maintained.

For Monday, light southwest wind in the morning will become
south-southeasterly around 10 mph in the afternoon. Breaking
wave heights of 1-3 feet. Easterly swell around 2 feet at 7-9
seconds in length. Monday is also still within two days of the
full moon. Will continue with a MODERATE risk for the
development of dangerous rip currents at all beaches.

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

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Gorse/Johnson
NEAR TERM...MJL
SHORT TERM...Gorse/Johnson
LONG TERM...Gorse/Johnson
AVIATION...Johnson/MJL
MARINE...Cooper/Johnson/MJL