Big Boulder

000
FXUS61 KPHI 221759
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
159 PM EDT Sat Aug 22 2026

.WHAT HAS CHANGED...
Updated Aviation section for the 18Z TAFs.

&&

.KEY MESSAGES...
1. One disturbance passes off the Mid-Atlantic coast today, 
followed by a cold front late tonight through Sunday morning. A
period of showers and thunderstorms is likely with localized 
flooding.

2. Fair weather is expected to return Monday and should last 
into the middle of next week.

&&

.DISCUSSION...
KEY MESSAGE 1...One disturbance passes off the Mid-Atlantic 
coast today, followed by a cold front late tonight through 
Sunday morning. A period of showers and thunderstorms is likely 
with localized flooding.

The base of an upper trough associated with an H5 low over 
central Canada will move through the Mid-Atlantic later today.
Some showers, perhaps a thunderstorm, will impact Delmarva and
extreme southern New Jersey later this morning into early
afternoon. However, the previous threat for flooding has
diminished as the heaviest rain looks to stay south and east of
the area. WPC has removed the Slight Risk (2/4) for Excessive
Rainfall and the Marginal Risk (1/4) is focused on Delmarva and
Cape May county in New Jersey. 

A cold front approaches tonight and the upper trough becomes
negatively tilted over the Northeast. Another round of showers
and possible thunderstorms will develop late tonight and
continue into Sunday morning. Instability will be marginal with
up to 500 or so J/kg of SBCAPE and MUCAPE, but 0-6 km Bulk Shear
values will be upwards of 45 to 50 kt. CAMs showing the
potential for some strong to possibly severe thunderstorms
mainly north and west of Philadelphia and into northern New
Jersey after midnight tonight and into the pre-dawn hours Sunday
morning. Locally heavy rain may lead to instances of localized
flash flooding in these areas as well.

Cold front passes through the region Sunday morning with conditions
improving for Sunday afternoon.

KEY MESSAGE 2...Fair weather is expected to return Monday and 
should last into the middle of next week. 

More zonal flow with some subtle ridging moves in for the first
half of the week. At the surface, high pressure will mainly be 
in control, resulting in dry and tranquil weather through 
Wednesday. Temperatures should be seasonable through this 
stretch.

&&

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

Rest of today...Mostly VFR across the terminals as of early 
afternoon (except KACY). Scattered showers across Delmarva and 
south NJ will keep lower conditions (MVFR) there. Lower 
conditions will develop toward evening. E-SE winds 5 to 10 kt. 
Low/Medium confidence.

Tonight... Lower conditions with widespread MVFR for the evening  
then IFR mostly with Scattered showers and areas of fog. TSTMs 
may arrive late tonight as a front approaches. Continued with 
the VCTS for now with limited confid in TSTM occurrence. Low 
confidence.

Outlook...

Sunday night through Thursday...VFR expected most of the time. 

&&

.MARINE...
Sub-Small Craft Advisory conditions on the waters today and
tonight. East winds around 10 kt will become SE 10 to 15 kt
later today and tonight. Ocean seas will average 2 to 3 ft. 
VSBY restrictions in showers and perhaps a thunderstorm today,
then another round of showers and thunderstorms will impact the
waters late tonight. 

Outlook...

Sunday through Wednesday...No marine headlines expected. 
Showers continue Sunday morning, ending Sunday afternoon. Fair 
weather thereafter. 

Rip Currents...

Today...East to southeast winds 10 to 15 mph with breaking 
waves of 2 to 3 feet and easterly swells with a period of 6 to 8
seconds will result in a MODERATE risk for the development of 
dangerous and life threatening rip currents for the Jersey Shore
and a LOW risk for Delaware Beaches.

On Sunday, winds shift to the southwest at 10 to 15 mph in the 
morning, then to the west in the afternoon. Breaking waves will
be 1 to 2 feet with light southerly swells with a 6 to 8 second
period. As a result, there is a LOW risk for the development of
dangerous and life threatening rip currents at the Jersey Shore
and at Delaware Beaches.

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

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

DISCUSSION...MPS/OHara/Staarmann
AVIATION...OHara
MARINE...MPS/OHara/Staarmann