905
FXUS61 KPHI 222017
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
417 PM EDT Wed Jul 22 2026

.WHAT HAS CHANGED...
Updated rip currents discussion to include Friday`s forecast.

Increasing confidence in two different systems bringing rain
chances early next week.

&&

.KEY MESSAGES...
1) Marginal risk of severe storms with slight risk of enhanced
rainfall this afternoon into this evening, followed by drier
weather for the end of the week into much of the weekend.

2) A pair of systems will bring more thunderstorm chances early
next week.

&&

.DISCUSSION...
KEY MESSAGE 1...A marginal risk for severe storms and a slight
risk of enhanced rainfall remains for portions of the area this
afternoon into this evening.

A cold front will continue to move across the area this
afternoon into this evening and overnight. Ahead of the cold
front, warm/humid air will remain in place across eastern New
Jersey, as well as central/southern Delaware and eastern
Maryland, leading to CAPE values of 1000-2000 J/kg. As a mid-
level/ short wave/vorticity impulse moves across the area this
afternoon into tonight, showers and thunderstorms should
develop across the area. With 1000-2000 J/kg of CAPE, along with
shear values near 30-40 knots, a few strong to severe storms
may develop across portions of eastern New Jersey, as well as
central/southern Delaware and eastern Maryland. With PW values
in the 1.5-2.0 range, heavy rainfall will also remain possible.

After tonight, the front will shift offshore, bringing the rain
with it. As high pressure builds in from the north, dry weather
will return through the much of the weekend.


KEY MESSAGE 2...A pair of systems will bring more thunderstorm
chances early next week.

An open wave, mid level, short wave trough will be crossing
through the Northeast on Sunday. Currently, we have relatively
low chances for precipitation with this trough, primarily
because there is limited opportunity for moisture advection
before this trough arrives. Additionally, at this point there
doesn`t appear to be much in the way of boundary layer
convergence.

There is a different story with the next mid/upper level trough
approaching our region Tuesday into Wednesday. For this system,
there will likely be ample opportunity for moisture advection
Monday into Tuesday. Additionally, it is likely to be
accompanied by a low and at least a cold front at the surface.
That being said, there is considerable differences between
models on how this system will evolve. Some models are depicting
this as an open wave, fast moving trough with only a limited
opportunity for rain. Others, most notably the ECMWF, depict the
mid upper level trough becoming a closed low, and then slowing
its eastward progress considerably. Given the large differences
in uncertainty, forecast stays close to the blend of guidance
through this period.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Rest of Today...VFR conditions should remain at all TAF
locations. West winds will gust around 20-25 knots, before gusts
drop off late this afternoon and through sunset. High
confidence.

Tonight...Mostly VFR conditions are expected for all TAF sites
through tonight. The only exception is for ACY and MIV where a
shower or thunderstorms remains possible this evening,
especially during the 22z-02z time period. Otherwise, the rest
of the area is expected to remain dry. Winds will become
northwest this evening behind a cold front, before shifting to
the north or north-northeast overnight with speeds around 5-10
knots or less. Moderate confidence.

Thursday...VFR conditions expected. North to northeast winds
5-10 knots, becoming light and variable Thursday night.

Outlook...

Friday through Saturday...VFR.

Sunday...Mainly VFR.

&&

.MARINE...
Seas will remain elevated on the Atlantic Ocean, so a Small
Craft Advisory will remain through this evening.

Outlook...

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

Rip Currents...

For Thursday, winds will be out of the north and northeast 10-20
mph. Breaking waves are expected to be 2-4 feet with a 7 second
period. With the onshore component of the wind and multiple swell
groups expected, will maintain a MODERATE risk for the development
of dangerous rip currents at all beaches.

For Friday, very similar conditions to Thursday are expected so
we`ll go with a MODERATE risk for the development of dangerous rip
currents for all beaches once again.

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

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 2 AM EDT Thursday for ANZ450>455.

&&

$$

DISCUSSION...Johnson/Robertson
AVIATION...Gorse/Robertson
MARINE...Fitzsimmons/Gorse/Robertson