477
FXUS61 KPHI 132018
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
418 PM EDT Fri Sep 13 2024

.SYNOPSIS...
Surface high pressure will dominate our weather into early next
week. By then, a possible tropical disturbance will be located
off the Southeastern United States coastline which may bring
some rain back to the region by the middle of next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
High pressure to our north will continue to dominate our
weather through Saturday. The positioning of the high continues
to allow weak onshore flow to infiltrate into the region,
reinforcing moisture into the low-levels. This has been
resulting in some overnight and early morning stratus and fog
the past couple days. Currently, however, the fog/stratus has
burned off and it`s another pleasant afternoon. Expect highs to
top out in the mid to upper 70s near the coast and over the
southern Poconos with low to mid 80s elsewhere.

For tonight, given the stagnant weather pattern, should expect
the re-development of low stratus and foggy conditions overnight
into early Saturday especially for areas near and south/east of
the urban corridor. Lows tonight across the region will be
fairly uniform in the upper 50s to low 60s.

Not too much change expected for Saturday as early morning
fog/stratus will once again give way to mainly sunny skies by
afternoon. Most areas should see high temperatures a few degrees
warmer compared to this afternoon as upper ridging continues to
build with highs mainly ranging from the upper 70s to the upper
80s. Humidity levels will remain comfortable.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Another surface high will build southeastward from eastern
Canada during the start of the period with upper-level ridging
remaining west of the area. THe upper-level ridge then becomes
closed off over the northeastern US with the surface high
centered underneath. This will reinforce a northeasterly to
easterly flow across the region through the remainder of the
weekend and into early next week, but with light pressure
gradients, overall winds will remain 10 mph or less. The
easterly fetch should keep adding low-level moisture to the
region, which when combined with the high nearby should promote
late night and early morning patchy fog and low clouds, but
there may be enough wind to keep widespread fog at bay.
Otherwise, mid-days through evenings will be tranquil with
mostly clear skies. Some upper-level cirrus may encroach on the
area, particularly later in the day on Monday as a low looks to
begin to develop to our southeast. Lows near 60 Saturday night
dropping into the 50s most everywhere Sunday night. Highs in the
upper 70s to low 80s for both Sunday and Monday.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
High pressure looks to hang on through Monday night, but thereafter
we will need to watch for any potential tropical development
off the southeast coast. Still much uncertainty with this, but
as the week progresses, clouds and shower chances will elevate a
bit. Latest guidance continues to depict high pressure
suppressing the core of the low to our south and west but a few
shortwaves look to spin off and push northward towards our
region. As a result, slight chance to chance POPs are in the
forecast beginning Tuesday/Tuesday night through the end of the
upcoming work week. With the system potentially affecting us
toward mid- week, allow highs to drop a few degrees to be mainly
in the upper 70s.

&&

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

This afternoon...VFR with mainly sunny skies. Northeast winds
becoming southeast around 5-10 kt. High confidence.

Tonight...VFR to start, with likely another round of low
stratus and patchy fog overnight bringing restrictions to most
sites. Expect most sites, with the possible exceptions of RDG
and ABE, will see at least times of IFR conditions with the most
significant restrictions likely being at MIV and ACY where fog
could bring visbys to a half a mile or less. Winds light and
variable. Moderate confidence there will be stratus and fog but
low confidence on the specific details and timing in the TAFs.

Saturday...Early morning restrictions from fog/stratus improving
to VFR by the 14-15z time frame, similar to this morning. Winds
northeast to east around 5 to 10 knots. High confidence on
overall trend, low confidence on specific timing details for
each TAF site.


Outlook...
Saturday night through Monday...Mainly VFR through the period,
though sub-VFR cigs and vsby possible during the late night and
early morning hours due to patchy low clouds and fog.

Tuesday and Wednesday...Mainly VFR but chance for showers,
currently most likely on Wednesday.

&&

.MARINE...
No marine headlines are expected through Saturday. East-
northeast winds around 5-10 kt with occasional gusts up to 15-20
kt. Seas of 2-3 feet. Localized patchy fog possible.

Outlook...
Saturday night...Conditions mainly below Small Craft Advisory
criteria with gusts up to 15 kts and waves up to 4 ft.

Sunday through Wednesday...Small Craft Conditions looking
likely with waves building to 5-8 feet and wind gusts up to 20
kts.

Rip currents...

For Saturday and Sunday, east to northeast winds will average 10
to 15 mph. Breaking waves will average 2 to 3 feet with an 8 to
9 second period. With this onshore flow, there is a MODERATE
risk for the development of dangerous and life threatening rip
currents for both the Jersey Shore and the Delaware Beaches for
both Saturday and Sunday, however, there is the potential for a
HIGH risk on Sunday if winds are a bit stronger.

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

&&

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

&&

$$

SYNOPSIS...DeSilva/RCM
NEAR TERM...DeSilva/Fitzsimmons
SHORT TERM...AKL/RCM
LONG TERM...AKL/RCM
AVIATION...AKL/DeSilva/Fitzsimmons
MARINE...AKL/DeSilva/Fitzsimmons/MPS