779
FXUS61 KPHI 180909
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
509 AM EDT Mon Aug 18 2025

.SYNOPSIS...
A cold front moving southward across the area early this
morning will become stationary over southern Virginia during the
day today. 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 TUESDAY/...
A cold front is pushing its way south across the area early this
morning while an expansive area high pressure builds in to our
north over Ontario into Quebec. As result of this setup, today will
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 and
areas of light drizzle around, especially over Delmarva and
south Jersey. 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 skies that
will generally be mostly cloudy. It`ll also be quite windy where
NE winds may gust occasionally up to 20-30 mph before tapering
off later in the day.

For tonight, there may be some partial clearing across NE PA
and northern NJ as some drier air tries to work in. Otherwise,
it stays mainly cloudy with some continuing chances for spotty
light showers and drizzle with the front still lingering nearby
to our south. Once again, the best chances for this will be over
Delmarva and southern NJ. Expect lows by Tuesday morning
ranging from the mid 50s north to the middle to upper 60s south.

Cool weather with onshore flow persists Tuesday as high
pressure remains centered to our north over Quebec into New
England with the remnants of the aformentioned front and its
moisture still lingering across the mid Atlantic. As result, it
will be another cool day with highs in the 70s. Some partial
clearing looks to try to work in to portions of central and
northern NJ with more in the way of cloud cover persisting
farther west. A few sprinkles or light showers remain possible
over Delmarva but it should otherwise be mainly dry.

&&

.SHORT TERM /TUESDAY NIGHT/...
Tuesday night will feature a cooler evening as the stalled
frontal boundary stays south of the region. High pressure will
being to weaken as easterly on shore flow continues through the
night. There`s a small chance (less than 20%) that the winds
will decouple leading to some patchy ground fog. However with
cross over temps in the mid to upper 50s and lows forecast to be
in the low 60s, its not very likely to see much fog
development.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Generally benign weather conditions with seasonable to
seasonable cool temperatures expected from Wednesday through
Saturday across the region.

The main focus of the extended will be the impacts of Hurricane
Erin for both the shore and marine communities. While the
forecast from NHC is forecast to remain well offshore, the long
period swell and high surf will bring significant impacts to
communities along the shore. 8 to 10 foot seas on Wednesday will
build to as high as 12 to potentially 15 foot seas Thursday
before starting to wane into Friday. The high seas will result
in high surf, dangerous rip currents, beach erosion, and coastal
flooding. Rip Current Statements are already in effect and will
remain in effect through at least Thursday.

Please refer to the National Hurricane Center for more details
and stay tuned to the local forecast. https:/www.nhc.noaa.gov/

For the end of the weekend, a frontal system will bring more
unsettled conditions Sunday into next Monday.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...An MVFR stratus deck will continue to develop across the
area early this morning and persist through much of the day.
Some slight improvements to cigs possible late day at RDG and
ABE with low VFR indicated here after 20z. A slight chance of
rain showers near KACY/KMIV, otherwise dry conditions. Winds
northeast 10 to 15 knots with gusts of 20 to 25 knots possible.
Moderate confidence.

Tonight...Some continuing improvement to low VFR cigs possible
from north to south but confidence is low on this since onshore
flow will be persisting. Winds generally east/northeast 5 to 10
knots. Low confidence.

Outlook...

Tuesday...Mainly VFR except there still could be some lingering low
stratus in the morning at MIV and ACY. East winds around 7-12 knots.
Low confidence.

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

Thursday and Friday...VFR.

&&

.MARINE...
Small Craft Advisory conditions developing this morning from
north to south as a cold front crosses the waters and northeast
winds ramp up to 20-25 gusting up to 30 knots. Seas build to 6
to 8 feet by late day today.

Winds start to diminish some this evening with Small Craft
Advisory conditions ending on the Delaware Bay. But for the
ocean waters, SCA conditions continue through Tuesday and beyond
due to high seas.

Outlook...

Tuesday 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 20-25 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...Coastal Flood Advisory from 4 PM this afternoon to 10 PM EDT
     this evening for NJZ022>025-027.
     High Risk for Rip Currents from 8 AM EDT this morning through
     Tuesday evening for NJZ014-024>026.
DE...Coastal Flood Advisory from 4 PM this afternoon to 10 PM EDT
     this evening for DEZ003-004.
     High Risk for Rip Currents from 8 AM EDT this morning through
     Tuesday evening for DEZ004.
MD...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ430-
     431.
     Small Craft Advisory until 6 AM EDT Friday for ANZ450>453.
     Small Craft Advisory until 6 AM EDT Friday for ANZ454-455.

&&

$$

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