Forecast Discussion

192
FXUS61 KPHI 211821
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
221 PM EDT Thu Aug 21 2025

.SYNOPSIS...
Hurricane Erin lies several hundred miles east of the Carolina
coast and will track out to sea tonight through Friday.
Meanwhile, high pressure centered over the Great Lakes will
build east, and will eventually be overhead on Friday before
departing this weekend. A cold front passes through the region
Sunday night through Monday morning, followed by another cold
front on Tuesday. High pressure returns for the middle to the
end of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
Overnight, Hurricane Erin has already made its closet
`approach` to our shore, remaining about 350 miles SE of Cape
May this afternoon. It`ll continue to move northeast away from
our waters tonight. We`ll continue with the marine/land hazard
flags as they are since the effects for the system are ongoing.
Precipitation has been mostly been only light rain and/or
drizzle across NJ/ern DE today with limited totals. Sky cover
will decrease from NW to SE overnight. Gusty N to NE winds will
diminish slowly tonight. Lows will drop to between 55 and 60
degrees.

For Friday, we are expecting fair weather to prevail across the
region as Erin continues to move away and high pressure builds
across the Middle Atlantic. The pressure gradient between the
two systems will have weakened overnight, there will still be
some locally gusty winds along the shore areas early on. Skies
are expected to be sunny throughout the day. High temperatures
should top out in the low 80s for most spots and some upper 70s
for the far NW counties. North to Northwest winds mostly around
10 mph on average.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
High pressure will build down into the region and will be
centered over the area Friday night. By Saturday, high pressure
will be offshore, and return flow sets up behind the departing
high. A cold front approaches from the west starting Saturday
night, then will be through western New York and western
Pennsylvania by Sunday morning. The front then slowly tracks
east during the day Sunday.

In terms of sensible weather, clear and cool Friday night with
lows in the upper 50s to low 60s, warmer along the coasts due to
the warmer ocean temperatures. Temperatures in outlying areas
may even end up several degrees cooler than forecast due to
radiational cooling. Sunny and mild on Saturday with highs in
the low to mid 80s. Warmer and more humid air begins to build
into the region Saturday night and Sunday. Lows will be in the
60s Saturday night and highs will be in the low to mid 80s
Sunday. Dew points begin to rise as will be in the mid to upper
60s Saturday night and Sunday. Showers and scattered
thunderstorms develop Sunday afternoon ahead of that cold front.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Showers and thunderstorms will continue to impact the area
Sunday night through Monday morning with the passage of the cold
front, but the cooler and drier air will not make it to the
region until Monday night and Tuesday. A weak secondary front
passes through the region Tuesday. Only a few showers will be
possible in the southern Poconos. Cool and dry for the middle of
next week as high pressure builds in from the north and west.

Lows will be in the 60s Sunday night, then highs will be in the
low to mid 80s Monday. After that, lows will be in the 50s and
low 60s Monday night, then in the low to mid 50s Tuesday night
and Wednesday night. Highs will generally be in the mid 70s or
so for Tuesday through Thursday, which are some 10 degrees or so
below normal for this time of year!

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...The southern NJ TAF sites (KMIV,KACY) will see
continued improvement back to VFR as the hurricane offshore
continues to move away. Other sites should be VFR by sunset and
will continue that way overnight. Gusty North winds 10 to 15 kts
with gusts around 25 kts diminishing overnight. Winds lighter
for KRDG,KABE. Medium/high confid.

Friday...VFR expected. Few if any clouds. Gusty NW winds during
the first part of the day then diminishing. High confid.

Outlook...

Friday night through Saturday night...VFR. NSW.

Sunday through Monday...Generally VFR, but brief sub-VFR
conditions possible in any SHRA/TSRA from Sunday afternoon
through Monday afternoon.

Monday night through Tuesday...VFR. NSW.

&&

.MARINE...
Marine tropical and non-tropical flags to continue as Hurricane
Erin now heads NE away from the area. Northeast winds 20 to 30
kts with gusts to 45 kts early becoming North and slowly
diminishing overnight. Powerful and dangerous seas. Scattered
rains, mostly early tonight. Fair Friday.

Outlook...

Friday night through Saturday night...SCA conditions due to
elevated seas from departing Hurricane Erin.

Sunday through Monday...Sub-SCA conditions. VSBY restrictions
and locally higher winds and seas in showers and thunderstorms
late Sunday through Monday.

Monday night through Tuesday...Sub-SCA conditions.

Rip Currents...

YOU ARE RISKING YOUR LIFE IF YOU GO IN THE WATER!

For today, northeast winds 25-35 mph with gusts up to 50 mph.
Dangerous surf zone conditions continue as breaking waves peak
at 7-12 feet along with long period southeasterly swells (15-18
seconds) still associated with Hurricane Erin. A HIGH risk for
the development of life-threatening rip currents continues for
the Jersey Shore and the Delaware Beaches.

For Friday, conditions begin to improve but still expecting
high waves of 5 to 9 feet and a long period 13 to 16 second
swell with Hurricane Erin pulling away. A HIGH risk for
development of life-threatening rip currents will remain through
the end of the week.

A HIGH risk of rip currents is likely to persist through
Saturday, and possibly Sunday as well.

A High Surf Advisory and High Risk for Rip Currents statement
are in effect through Friday for the New Jersey and Delaware
Atlantic coasts. Waves in the surf zone will reach and exceed 8
feet, and a high risk of rip currents will persist through the
end of the week.

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

&&

.TIDES/COASTAL FLOODING...
Prolonged and strengthening northeast winds will result in
periods of coastal flooding through the end of this week. Water
will slowly pile up as onshore flow continues through this
evening. Swells from Hurricane Erin will also enhance the
threat for tidal flooding and push of water onshore, especially
this evening when the most significant and widespread coastal
flooding impacts are expected. Widespread minor coastal flooding
is forecast to occur with this morning`s high tide from around
Barnegat Bay south through coastal Delaware.

A widespread impactful coastal flood event is expected as Erin
passes by offshore today into Friday. The Coastal Flood Warnings
remain in effect for all counties along the Atlantic Ocean and
within Delaware Bay, where widespread moderate flooding is
expected along the coast. There is potential for locally MAJOR
coastal flooding impacts, especially in Sussex County, DE and
Cape May County, NJ, where we are now forecasting water levels
to reach MAJOR flood stage at Lewes and Cape May. The greatest
inundation and impacts can be expected with this evening`s high
tide. Widespread minor flooding is forecast with the Friday
morning high tide, then additional moderate coastal flooding is
possible with the Friday evening high tide.

Along the tidal Delaware River, widespread minor flooding is
expected, beginning with tonight`s high tide and continuing
through the high tide late Friday Night/early Saturday morning.
A Coastal Flood Advisory remains in effect for communities
along the tidal Delaware River, beginning tonight and
continuing through Saturday morning.

Currently, no widespread coastal flooding is forecast for our
Chesapeake Bay shoreline until Saturday morning`s high tide,
though confidence is low on exactly how widespread the tidal
flooding will be.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from 11 PM this evening to 5 AM EDT
Saturday for PAZ070-071-106.
NJ...Coastal Flood Advisory from 9 PM this evening to 2 AM EDT
Saturday for NJZ016.
Coastal Flood Warning until 2 AM EDT Saturday for NJZ020-
022>027.
High Risk for Rip Currents through Friday evening for NJZ014-
024>026.
High Surf Advisory until 8 PM EDT Friday for NJZ014-024>026.
Wind Advisory until midnight EDT tonight for NJZ024>026.
Coastal Flood Warning until 2 AM EDT Saturday for NJZ012>014-
021.
Coastal Flood Advisory from 11 PM this evening to 5 AM EDT
Saturday for NJZ017>019.
DE...Coastal Flood Advisory from 9 PM this evening to 2 AM EDT
Saturday for DEZ001.
Coastal Flood Warning until 2 AM EDT Saturday for DEZ002>004.
High Risk for Rip Currents through Friday evening for DEZ004.
High Surf Advisory until 8 PM EDT Friday for DEZ004.
Wind Advisory until midnight EDT tonight for DEZ004.
MD...None.
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ430.
Gale Warning until midnight EDT tonight for ANZ431.
Gale Warning until 6 AM EDT Friday for ANZ450.
Tropical Storm Warning for ANZ451>455.
&&

$$

SYNOPSIS...MPS
NEAR TERM...OHara
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...MPS/OHara
MARINE...MPS/OHara
TIDES/COASTAL FLOODING...

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Data at: 0000 UTC 03 Sep 2023

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