686
FXUS61 KPHI 221420
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1020 AM EDT Wed Jul 22 2026

.WHAT HAS CHANGED...

Updated for a few showers across eastern Pennsylvania and
northern New Jersey and updated aviation for improvement to VFR.

&&

.KEY MESSAGES...
1) Isolated severe thunderstorms possible this afternoon, mainly
south and east of the urban I-95 corridor. A localized flash flood
risk today for mainly portions of Delmarva. It then turns much drier
and pleasant for the end of the week.

&&

.DISCUSSION...
KEY MESSAGE 1...Isolated severe thunderstorms possible this
afternoon, mainly south and east of the urban I-95 corridor. A
localized flash flood risk today for mainly portions of Delmarva. It
then turns much drier and pleasant for the end of the week.

A strong upper-level trough will remain across the Northeast and Mid-
Atlantic regions today into Thursday. Some additional shortwave
energy will continue to slide across our area today as a result.

A cold front associated with the aforementioned upper-level trough
will gradually arrive later today. The deep moisture continues to
shift eastward today given the eastward progression of the upper-
level trough. While a surface trough has shifted offshore overall,
the main cold front will arrive by later today. The forecast
challenge is how much convection redevelops ahead of the cold front
through this afternoon. The majority of the guidance is limited with
convective redevelopment through today with the arrival of the cold
front. The combination of greater instability and shear looks to
reside near Delmarva and especially on southward where the severe
thunderstorm risk looks a bit higher. For our area, an isolated
severe thunderstorm risk is present mostly focused south and east of
the I-95 urban corridor this afternoon. If a few storms can become
strong enough, then conditions look favorable for locally strong to
damaging outflow driven winds.

There is also a chance for a few showers, with an occasional
rumble of thunder, to move across portions of eastern
Pennsylvania and northern New Jersey around midday through the
afternoon hours as the cold front moves across the area.

There will be drier air gradually working in from the west and
northwest through today, which will result in the dew points
gradually lowering from north to south through this afternoon.
Despite the deeper plume of moisture shifting eastward today
resulting in the precipitable water values decreasing with time, it
will still be very near Delmarva. Therefore, some local flash
flooding risk for that area if some deeper convection occurs and
moves over areas that just recently had heavy rainfall. This risk
looks even lower if convective coverage ends up remaining less. Once
the front moves away later today into tonight, it turns much drier
and pleasant for the end of the week and right into the weekend.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...Ceilings have improved to VFR everywhere this morning
and should stay VFR for the remainder of the day. A few showers
and thunderstorms possible especially south and east of KPHL,
especially this afternoon. Maintained a PROB30 for a
thunderstorm at KMIV and KACY this afternoon, with no mention
elsewhere due to more limited coverage. Southwest winds 10 knots
or less increasing to 10-15 knots with gusts 20-25 knots by
later this morning, then becoming west to west- northwest this
afternoon. Low confidence.

Tonight...A shower or thunderstorm possible early mainly near KMIV
and KACY, otherwise VFR. North-northwest winds 5-10 knots becoming
north-northeast or locally light and variable. Moderate confidence.

Outlook...

Thursday through Saturday...VFR.

Sunday...Mainly VFR.

&&

.MARINE...
The Small Craft Advisory for Delaware Bay expired at 6 AM.

Southwesterly flow will gust to advisory criteria (25 knots) at
times this morning, otherwise the winds are expected to diminish
some through the day. Seas remain elevated on the ocean zones, where
a Small Craft Advisory continues through this evening.

Outlook...

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

Rip Currents...

For today, southwesterly winds 10-20 mph however breaking waves in
the surf zone will be as high as 5 feet. Still a 7 second period
which will mitigate the rip current threat some, however will
continue with a MODERATE risk for the development of dangerous rip
currents at all beaches.

For Thursday, winds 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 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...Gorse/Robertson
AVIATION...Gorse/Robertson
MARINE...Gorse/Hoeflich/MJL