903
FXUS61 KPHI 191046
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
646 AM EDT Thu Sep 19 2024

.SYNOPSIS...
A coastal low will meander off the Mid-Atlantic coast through Friday
bringing several low chances for showers across the area. The
low departs the area on Saturday as high pressure builds in over
the weekend into early next week. A cold front may approach the
area by the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Early morning forecast remains on track. Only minor adjustments
will be made to the hourly grids this morning based on the
latest surface obs.

Otherwise, low pressure meanders off the New Jersey and
Delmarva coasts. Meanwhile, high pressure builds down from
eastern Canada into the eastern Great Lakes and Ohio Valley.

While some bands of light showers will rotate around the low
and into the Mainland today and tonight, any showers will be
light and quite sporadic. Will carry slight chance PoPs, mainly
for eastern area, but a few showers could make it as far west as
the I-95 corridor. QPF will be minimal.

Some drier air will filter into areas west of the I-95 corridor
resulting in partly to mostly sunny skies. For areas east of
the I- 95 corridor, skies will generally be partly to mostly
cloudy.

With a bit more breaks in the clouds, highs today will climb
into the lower 80s for most areas away from the coasts, and
highs will be in the 70s near the coasts. Lows tonight will be
in the 50s to low 60s. Some patchy fog may develop late tonight.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
A deep upper trough will remain situated over the East Coast
through the term before finally pivoting away for the second
half of the weekend. The weak surface low currently over the
region will continue to meander off the coast of Long Island
through Friday night before departing later on Saturday
causing mostly cloudy skies to persist across the entire region
with low chances for showers generally along the coast.

Further west over parts of E PA, there may be some clearing at
times and more likely to remain dry through the term. High temps
will be rather uniform in the 70s with the warmest temps found
over western areas where clearing skies may occur at times. Lows
will mainly be in the upper 50s to mid 60s both Thursday and
Friday night.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The long term period as a whole looks to be tranquil before having
to monitor the next precipitation potential around midweek. The
upper trough will exit the region by Sunday as a brief and weak
upper level ridge fills in on Monday. During this time, surface high
pressure will be building over New England which will yield tranquil
weather through Monday. Heading into the middle portion of next
week, a leading shortwave will be quickly approaching around the
Tuesday timeframe ahead of a deep upper trough. This will bring the
return of some showers to the area as a cold front approaches around
mid-week.

In terms of temperatures, highs will be a bit below average and lows
will be close to normal for late September standards.

&&

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

Today...Some lingering MVFR CIGs possible at KMIV/KACY until
14Z or so. VFR otherwise. A few light SHRA possible at KMIV/KACY
today, but conditions will remain VFR. N-NE winds 5 to 10 kt.
High confidence.

Tonight...VFR initially, then MVFR CIGs or VSBYs possible in
stratus or fog late tonight. N winds 5 kt or less. Low
confidence in sub-VFR conditions so will not include in TAFs at
this time.

Outlook...

Thursday night through Saturday...Primarily VFR for all
terminals, with localized MVFR possible especially for KMIV/KACY
with a chance of rain showers.

Saturday night through Monday...VFR. No significant weather
expected.

&&

.MARINE...
A Small Craft Advisory remains in effect for New Jersey ocean waters
today and tonight for 6 to 8 ft seas that will subside to 4 to 6 ft
late tonight. A Small Craft Advisory remains in effect for the
Delaware ocean waters for 4 to 6 ft seas today, but seas should
subside to less than 5 ft by this evening. This SCA is in effect
until 6 pm. Seas may build back to over 5 ft late tonight, but
confidence is not high enough to issue a new SCA for the DE ocean
waters at this time. North to northeast winds will range from 15 to
20 kt, and occasional gusts to 25 kt for New Jersey ocean
waters.

Outlook...

SCA conditions will likely persist through the weekend into at least
early next week due to a prolonged duration of winds and seas. North-
northeast winds around 15-20 kt with occasional gusts around 25-30
kt. Seas of 4-6 feet building up to 6-8+ feet through Monday.

Rip currents...

Today, winds become north at 10 to 15 mph, along with breaking waves
of 3 to 4 feet with a 6 to 8 second period. This will result in a
MODERATE risk for the development of dangerous and life threatening
rip currents for the Jersey Shore and for the Delaware Beaches.

On Friday, winds become northeast and will increase to 15 to 20 mph
with gusts up to 25 mph. Breaking waves will be a bit higher,
generally 4 to 6 ft. As a result, there is a HIGH risk for the
development of dangerous and life threatening rip currents for the
Jersey Shore and for the Delaware Beaches.

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

&&

.TIDES/COASTAL FLOODING...
Continued onshore flow will result in water piling up and
unable to drain within tidal waterways. Minor tidal flooding is
expected for at least the next several high tide cycles for
portions of our area.

Coastal Flood Advisories were posted for the New Jersey coast,
Delaware Coast, and part of the Delaware Bay (Cumberland County
in New Jersey and Kent County in Delaware) as minor tidal
flooding is expected around high tide through the end of the
week at least. As a result, the Coastal Flood Advisory is not
just for tonight`s high tide, but through the high tide Friday
afternoon. Some of the guidance indicates moderate flooding
towards the end of the week, but will stick with the advisory
for now.

For the upper Delaware Bay and the tidal Delaware River, only
spotty minor tidal flooding is expected for this week.

No tidal flooding is expected along the northeastern shore of
Maryland currently at the moment.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Coastal Flood Advisory until 3 PM EDT Friday for NJZ012>014-
     020>027.
     High Risk for Rip Currents from Friday morning through Friday
     evening for NJZ014-024>026.
DE...Coastal Flood Advisory until 3 PM EDT Friday for DEZ002>004.
     High Risk for Rip Currents from Friday morning through Friday
     evening for DEZ004.
MD...None.
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ450>453.
     Small Craft Advisory until 6 PM EDT this evening for ANZ454-
     455.

&&

$$

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