090
FXUS61 KPHI 280720
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
320 AM EDT Thu Aug 28 2025

.SYNOPSIS...
High pressure will slide across the Mid-Atlantic today before
becoming centered offshore through tonight. A cold front crosses
our area later tonight and Friday, then high pressure builds in
over the weekend and early next week. An area of low pressure
may develop off the southeast coast next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The best days of the work week are behind us, at least weather-
wise. Approaching shortwave and cold front will bring a shift
to an occasionally gusty southwest wind today, along with a
notable increase in mid and high cloud cover. It won`t be fully
cloudy, but the sky will likely be much less blue than the last
few days (aside from the cumulus we had). Despite the filtered
sun and chilly start, the warm advection on southwest winds
should be enough to bring temps up a few degrees, likely
touching 80 in a few spots, but still on the cool side for late
August.

Tonight, the system continues approaching from the west, and
some showers may reach our northwestern zones overnight. Some
guidance also indicates spotty activity further south and east,
but odds of this look low right now, so kept POPs below slight
chance for areas southwest of NW NJ and the Lehigh Valley,
except right near the shore. The clouds and southwest wind ahead
of the front should keep lows notably milder tonight than this
morning, with much of the area staying in the 60s, with the rest
of the region (Lehigh Valley and NW NJ/Poconos) mainly in the
mid- upper 50s.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
An upper-level trough is forecast to amplify into the Northeast
and Mid-Atlantic regions Friday. This will drive low pressure
to our north with a cold front crossing the region Friday. A few
brief showers could occur with the cold front, however the
moisture return is not all that robust and the main forcing
slides by to our north. Overall, looks like much of the area
remains rain-free. The front shifts offshore through Friday
evening, with an uptick in cold/dry air advections. Temperatures
are forecast to be below average, and with some deeper mixing
occurring during Friday afternoon a west to west-northwest
breeze should increase. It will be chilly Friday night as the
winds then diminish, and low temperatures drop into the low/mid
50s with even some mid/upper 40s across the northern and western
zones.

The aformentioned upper-level trough, with a closed low
centered to our north and northeast Saturday, lingers across the
entire region. Despite this, the pattern favors surface high
pressure centered across the Great Lakes to build into our area.
This will reinforce the dry and cool/chilly conditions through
Saturday night.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Summary...Temperatures mostly below average, and dry weather
continues as long as low pressure develops off the Southeast
U.S. coast and remains far offshore through at least midweek.

Synoptic Overview...An upper-level trough is forecast to remain
across much of the East during this time frame. This trough
however looks to undergo some changes. Initial departing energy
results in the trough weakening for a time, then stronger energy
from the Midwest and vicinity next week may result in the
trough aloft strengthening into the East with time. The
amplitude and timing of this trough varies among the
guidance/ensembles but overall a more delayed eastward
amplification appears to be what the consensus is pointing
towards. This would lead to surface high pressure dominating
more of our sensible weather through this entire time frame.
There still remains some signal among the guidance/ensembles
that low pressure off the Southeast U.S. coast next week slowly
tracks northeastward. Its northward motion however may be halted
if high pressure over us becomes strong enough and dominates
more.

For Sunday....An upper-level trough from the Canadian Maritimes
back across the Northeast to Ohio Valley is forecast to
gradually weaken. This results in surface high pressure centered
across the Great Lakes to shift eastward and southward some
more into our area. Our sensible weather looks to be controlled
mainly by this area of high pressure and therefore dry
conditions are maintained. Little in the way of clouds are
anticipated due to the presence of surface high pressure and the
trough aloft weakening. Temperatures are forecast to remain
below average.

For Monday through Wednesday...The evolution of an upper-level
trough into the East will determine any impacts to our sensible
weather. The model guidance/ensembles differ on the amplitude of
this trough and also the timing into the East. This has
implications on a surface low that develops along a lingering
baroclinic zone off the Southeast U.S. coast and back into the
northern Gulf. The development could be slowed closer to midweek
as upstream energy hangs back longer. Some ensemble members of
the GFS show an organized surface low farther north Wednesday
with the bulk of them though much weaker. There remains model
variability with this given the timing/amplitude differences
with the upper-level trough. Surface high pressure northward may
end up dominating our sensible weather and therefore the
continuation of dry conditions. If the trough strengthens faster
into the East then the surface low could develop sooner
although with movement northward still uncertain. Temperatures
look to be near or below average across the region. Given the
uncertainty regarding low pressure development well to our
south, continued to ride with the National Blend of Models (NBM)
output which currently has no precipitation for our area.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Thru 12Z...VFR with WNW wind 5 kts or less. Winds look to
become light and variable for a period overnight. High
confidence.

Today...VFR with a SW wind around 5-10 knots, occasionally
gusting up to 20 kts. A sea- breeze at KACY and KMIV could
result in more southerly winds. High confidence.

Tonight...VFR with a SW wind around 5-10 kts. High confidence.

Outlook...

Friday...A few brief showers possible, otherwise mainly VFR.
West- northwest wind gusts to 20 knots possible during the day.

Saturday through Monday...VFR.

&&

.MARINE...
Today and tonight, seas build to 3-4 feet while the wind will
pick up out of the southwest by the afternoon and continue into
tonight. Winds will be 10-15 knots with gusts around 20 knots. A
few gusts to 25 kts are possible, with a few waves up to 5 feet
also possible, but confidence on more persistent Small Craft
Advisory conditions is low, so will hold off on an advisory for
now.

Outlook...

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

Rip Currents...

For today, winds shift southerly but remain around 10 mph
through much of the day. Breaking wave heights will be around
1-2 feet with a few 3 foot waves possible north. Easterly swell
will be around 1-2 feet around 7-9 seconds in length. Guidance
suggests marginally higher seas and swell for coastal Atlantic
and north, so went with a MODERATE RISK for this region with a
LOW RISK for coastal Cape May NJ and Sussex DE.

For Friday, winds remain offshore out of the SW to WSW around
10-15 mph. Breaking wave heights remain around 1 to 2 feet.
Combined with a weak easterly swell around 1-2 feet every 7 to 8
seconds, this will allow for a LOW RISK for rip currents across
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
NEAR TERM...RCM
SHORT TERM...Gorse
LONG TERM...Gorse
AVIATION...Gorse/RCM
MARINE...Gorse/RCM