235
FXUS61 KPHI 161046
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
646 AM EDT Sun Aug 16 2026

.WHAT HAS CHANGED...
Updated the Aviation section for the 12Z TAFs.

&&

.KEY MESSAGES...
1. A frontal system passes through the region later today and
tonight producing widespread showers with localized flash
flooding.

2. A trailing mid-level short wave trough and weak cold front
lead to the potential for additional rounds of showers and
thunderstorms on Monday.

3. A cold front is expected to cross through the region
Wednesday night into Thursday resulting in more shower and
thunderstorm chances.

&&

.DISCUSSION...
KEY MESSAGE 1...A frontal system passes through the region
later today and tonight producing widespread showers with
localized flash flooding.

High pressure over the area moves offshore during the early
morning hours. Low pressure over the Midwest tracks east. A warm
front ahead of that low lifts north through the region this
afternoon, and then this will be followed by low pressure
passing through the region late tonight.

Several waves of showers and scattered thunderstorms will
impact the area this afternoon and tonight. The first wave of
showers will develop as the warm front lifts north through the
region. Most rainfall associated with this front will average
1/4 to 1/2 inch.

Behind the warm front, moisture increases over the area,
resulting in surface dew points rising into the low 70s and
PWATs of 2 to 2.25 inches. With low pressure passing through the
region tonight, showers and scattered thunderstorms develop with
locally heavy rain. While localized flash flooding is possible
due to localized amounts of 1 to 2 inches of rain, most showers
will be fairly progressive, so will not issue a Flash Flood
Watch at this time. The Weather Prediction Center has a Marginal
Risk for Excessive Rainfall, which is a 1 out of 4. The Slight
risk has been cut back to portions to southeast Pennsylvania
west of Philadelphia.

The severe threat is fairly minimal, generally focused on
Delmarva where the Storm Prediction Center has a Marginal Risk
(1 out of 5) for Delmarva and extreme southern New Jersey.


KEY MESSAGE 2...A trailing mid-level short wave trough and weak
cold front lead to the potential for additional rounds of
showers and thunderstorms on Monday.

The cold front associated with the low that approaches the
region on Sunday will finally progress through the region and
move offshore on Monday. Additionally, in the the mid-levels, a
trailing short wave trough will cross overhead. The net result
is that isolated to scattered showers and thunderstorms will be
possible during the day on Monday.

As for hazards, this round appears to have very limited threats
for both flash flooding and severe weather. Convection on
Monday will be much more weakly forced (as compared to
Sunday/Sunday night), and bulk shear values are depicted in the
20 to 25 kt range, which is rather modest. Although there will
be instability present, the modest shear will limit storm
organization. Model soundings still depict relatively high
precipitable water values of upwards of 2 inches, and warm cloud
layers above 10K ft, which results in some heavy rain threat.
However, with limited shear and coverage of convection, the
threat for any one area to get heavy rain for long enough to
result in flash flooding remains low.

For those hoping for a significant cool down in the wake of
this cold front, unfortunately the temperature gradient is very
small. As such highs on Tuesday will be at or just a degree or
two lower than Monday. That being said, the front should usher
in drier air, so regardless it should feel more comfortable on
Tuesday.


KEY MESSAGE 3...A cold front is expected to cross through the
region Wednesday night into Thursday resulting in more shower
and thunderstorm chances.

The next main focus is another cold front arriving in the
region during the Wednesday night into Thursday time period.
There are some big timing differences between models on when
exactly the front will arrive and when the mid-level trough will
cross offshore. As such, there is considerable uncertainty with
the potential hazards as the severe and hydro threats will be
dependent on the prime time for any showers and thunderstorms.

In terms of temperatures, so far this appears to be a stronger
cold front compared to the one earlier in the week. As such,
temperatures by the end of the week and into the weekend are
currently forecast to be around 5 degrees lower compared to the
midweek time period.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...Conds will vacillate between VFR, MVFR and even IFR
until settling on MVFR by 15Z at the I-95 corridor terminals,
and then by 21Z at KMIV/KACY. SHRA develop by midday with
MVFR/IFR VSBYs. A few TSRA possible after 21Z, but will not
include in the TAF due to low confidence in a given TSRA passing
over a given terminal at a given time. SE wind less than 10 kt,
becoming S around 10 kt with gusts up to 20 kt. Moderate
confidence overall.

Tonight...IFR conds in SHRA/BR/low CIGs. After SHRA end, CIGs
will lower to LIFR late. S winds less than 10 kt. Low
confidence.

Outlook...

Monday...Isolated showers and thunderstorms may result in
temporary visibility and ceiling restrictions.

Tuesday and Wednesday...VFR conditions expected.

Wednesday night through Friday...Sub-VFR possible with the
chance for showers and thunderstorms.

&&

.MARINE...
Today...Southeast winds less than 10 kt will turn south and
increase to 15 to 20 kt with gusts up to 25 kt this afternoon.
Seas on the ocean will build to 3 to 5 feet late. A Small Craft
Advisory remains in effect for the waters starting this
afternoon. VSBY restrictions in showers developing this
afternoon.

Tonight...S winds 15 to 20 kt with gusts up to 25 kt and seas
around 5 feet. The SCA remains in effect through tonight. VSBY
restrictions in showers and fog. A few thunderstorms possible as
well.

Outlook...

Monday...Once seas subside below 5 ft Monday morning, winds and
seas are expected to then remain below SCA criteria.

Monday night through Friday...Conditions are expected to remain
below SCA criteria.

Rip Currents...

Today, southeast winds less than 10 mph will turn south and
increase to 15 to 20 mph with gusts up to 25 mph. Breaking
waves will average 2 to 3 feet. There will also be a light
easterly swell with a period of 8 to 10 seconds. As a result,
there is a LOW risk for the development of dangerous and life
threatening rip currents for the Jersey Shore in coastal
Monmouth county and for Delaware Beaches, and a MODERATE risk
for the Jersey Shore for coastal Ocean, coastal Atlantic, and
coastal Cape May counties.

On Monday, southwest winds 15 to 20 mph with gusts up to 25 mph
in the morning will turn west at 10 to 15 mph in the afternoon.
Breaking waves will average 1 to 2 feet. There will be an
increasing southerly swell with a 5 to 7 second period. For now,
there is a LOW risk for the development of dangerous and life
threatening rip currents for the Jersey Shore and Delaware
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 from 2 PM this afternoon to 4 AM EDT
     Monday for ANZ430-431.
     Small Craft Advisory from 4 PM this afternoon to 11 AM EDT
     Monday for ANZ450>455.

&&

$$

DISCUSSION...Guzzo/MPS
AVIATION...Guzzo/MPS
MARINE...Guzzo/MPS