640
FXUS61 KPHI 172336
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
736 PM EDT Sun Aug 17 2025

.SYNOPSIS...
A cold front will pass through the region tonight, becoming
stationary over southern Virginia on Monday. High pressure
builds in from the north through the middle to end of next week
as Hurricane Erin passes by well offshore.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 7:15pm...Scattered convection is ongoing across much of
the area this evening. Several outflow boundaries from earlier
storms are found over much of the area, which continue to spark
up some additional showers and storms. A more organized area of
convection is moving in from the west over extreme southern PA
and Maryland which is expected to move into southern NJ and the
Delmarva over the next few hours. Behind this, the cold front
will be advancing in from the north, shunting any residual
shower and storm activity to the south of our area.

Convection should come to an end by midnight as the frontal
boundary moves from north to south across the area. This will
cause winds to shift from SW to N/NE after midnight with a low
stratus deck likely setting up. Lows by Monday morning look to
range from around 60 north to around 70 near the urban corridor,
most of Delmarva, and coastal areas.

Monday looks to be sharply cooler compared to Sunday as
northeast flow and low status persist in the wake of the cold
front. The cold front will stall across southern Virginia and
since it will remain in our proximity, there may be some
lingering spotty showers around. Otherwise, the big story will
the cooler temperatures and lower dew points. In fact, much of
the area looks to see highs not getting out of the 70s under
mostly cloudy skies. It`ll also be quite windy where winds may
gust occasionally up to 20-30 mph before tapering off later in
the day.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
A cooler airmass will be moving into the region in the form of a
high pressure system. This will lead to onshore flow and a
continuation of the stark change in overnight lows and day time
highs with lows Monday night and Tuesday night expected in the
low to mid 60s and daytime highs Tuesday in the low to mid 70s.

A stalled frontal boundary lingering just south of the area
should lead to some isolated shower potential but not expecting
a washout by any means.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The stalled frontal boundary will continue to linger nearby
Wednesday and as some shortwave energy moves in from the west,
this will bring another chance for showers and possibly a few
embedded thunderstorms. Temperatures will remain on the cool
side of climo.

The highest impacts in the extended will be from the TC Erin.
The current forecast keeps the storm offshore, however the
prolonged period of onshore flow and high period swells will
likely cause high surf, dangerous rip currents, the potential
for beach erosion, and coastal flooding through the week.

Please refer to the National Hurricane Center for more details
and stay tuned to the local forecast.

The end of the week should feature benign sensible weather
conditions as high pressure should bring fair and dry weather
and seasonable temperatures. More unsettled conditions may
return Sunday.

&&

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

Tonight...VFR conditions early, followed by MVFR conditions
later in night (generally after 08Z) as a low stratus cloud deck
moves into the region. Scattered showers and thunderstorms will
linger through about 03Z, before tapering off. Convection
remains widely scattered, so opted to only mention VCSH in TAFs
for now as confidence is not high enough. Southwest winds around
5-10 kt will gradually veer to northwest and eventually
northeast while increasing to 10-15 G 20 kt overnight. Moderate
confidence overall, but lower confidence with regards to timing.

Monday...MVFR ceilings are likely to prevail at all terminals
for much of the day as low stratus deck remains. Skies may begin
to scatter out late in the day near KRDG/KABE. A slight chance
of rain showers near KACY/KMIV, otherwise dry conditions.
East-northeast winds around 10-15 kt with gusts up to 20-25 kt
possible.

Outlook...

Monday Night through Wednesday...Mainly VFR with periods of
sub- VFR conditions possible from showers and thunderstorms.

Thursday and Friday...VFR.

&&

.MARINE...
Southerly winds increase to around 15 to 20 knots but
conditions should stay below Small Craft Advisory levels. Seas
generally 2 to 3 feet.

Late tonight through Monday morning winds veer around to the
northeast in the wake of a cold front and also increase to
around 15 to 25 knots. Seas increase to 5 to 8 feet by late day
Monday. Small Craft Advisory begins at 09z Monday.

Outlook...

Monday night through Friday...SCA conditions continue due to
the approach of what is currently Hurricane Erin. Elevated winds
and seas develop Tuesday and will last into at least Friday.
Seas 5-7 feet Tuesday build as high as 8-14 feet by Thursday.

Rip currents...

For Monday, northeasterly wind around 20 mph. Breaking wave
heights generally 2-3 feet. Increasing long period swells
propagating from Hurricane Erin are expected to begin arriving.
Given these factors, have maintained the HIGH risk for the
development of dangerous rip currents at all area beaches.

For Tuesday, east-northeasterly wind 10-15 mph. Breaking wave
heights 3-6 feet. Long period southeasterly swells (potentially
near 20 seconds) associated with Hurricane Erin will continue.
There is a HIGH risk for the development of dangerous rip
currents at all area beaches.

A Rip Current Risk Statement will be in effect both Monday and
Tuesday, and will likely need to be continued further into the
week.

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

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...High Risk for Rip Currents from Monday morning through Tuesday
     evening for NJZ014-024>026.
DE...High Risk for Rip Currents from Monday morning through Tuesday
     evening for DEZ004.
MD...None.
MARINE...Small Craft Advisory from 6 AM Monday to 6 AM EDT Friday for
     ANZ450>455.

&&

$$

SYNOPSIS...Franklin
NEAR TERM...DeSilva/Fitzsimmons/Franklin
SHORT TERM...MJL
LONG TERM...MJL
AVIATION...DeSilva/Franklin/MJL
MARINE...Cooper/DeSilva/Franklin/MJL