-- Discussion containing changed information from previous version are highlighted. --
643
FXUS61 KPHI 222308
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
708 PM EDT Sun Sep 22 2024

.SYNOPSIS...
High pressure centered over eastern Canada continues to sag down
into the Northeast and Mid-Atlantic for the start of the new week.
This high will eventually lift to the north and east by the middle
of this week. Low pressure approaches from the west and will slowly
drag a cold front towards the region by the middle to end of this
week. Another area of high pressure may follow for next weekend.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 6:00pm, not much ongoing around the region at the moment.
Partly to mostly cloudy skies continue with temperatures in the
upper 60s to mid 70s.

As we head into the first half of the night, most will continue
to see mostly clear skies. Western portions of the area should
begin to see a few more clouds. For the second half or towards
daybreak, clouds will be on the increase as the next disturbance
approaches. Some patchy fog is possible. Lows will be in the
upper 40s to upper 50s. Locales on the water, will drop back
into the lower 60s. Winds will be less then 10 mph from the NE/E.

For Monday, clouds will continue to thicken and lower. We have
more confidence in this versus the extent of any showers
falling from them later in the day. For now, we`ll carry slight
chance of PoPs in the afternoon through Berks and the Lehigh
Valley. Highs will be in the lower 60s to lower 70s. Winds will
be 5 to 10 mph from the NE/E, except 10 to 15 mph at the beaches.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
For the start of the short term, high pressure to the north and east
will gradually lift away. This will allow the low pressure system
and associated cold front to slowly make some progress eastward and
approach the Northeast and Mid-Atlantic.

PoPs for Monday night are slight chance to chance over the western
zones, but rainfall should be minimal. Lows in the mid 50s near 60
at the coast and in the heart of the I-95 corridor. The base of the
high does look to build back down into the Northeast on Tuesday, so
much of Tuesday should end up dry with seasonal temperatures in the
lower 70s.

The frontal system will be able to make some eastern headway Tuesday
night, and showers will begin to spread east late Tuesday night and
continue into Wednesday. A bit of instability may come for daytime
Wednesday as the mid and upper level dynamics become more favorable.
This could result in a brief localized downpour or a rumble of
thunder. Generally, though precipitation totals for daytime
Wednesday look to be in the 0.1-0.75 range with the highest totals
in the western zones closer to the front.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Unsettled weather on tap to start the Long Term period before high
pressure potentially builds back in to end the week and for next
weekend.

As the mid-level trough approaches from the west later Wednesday
into Wednesday night, this may allow a secondary low to form on the
front as it passes through the region. Showers will become likely
for most of the region Wednesday night as this system passes
through. Cannot rule out a few thunderstorms as well.

There are some timing issues with how long it will take the front to
depart, so showers may continue into Thursday but much of Friday and
next weekend look dry. Will follow NBM PoPs and carry slight chance
(15-25%) PoPs Thursday across the area, then slight chance PoPs
limited to portions of the southern half of the region for Friday
through Sunday, though most of this period may end up being dry.

&&

.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...VFR likely. Some fog is possible near all terminals,
but confidence is very low, so it is still not mentioned in any
of the TAFs. If it were to develop, visibilities would be in
the MVFR range. Light winds less around 5 kt. Moderate
confidence.

Monday...Primarily VFR expected. Slight chance of MVFR ceilings
late in the day near KRDG/KABE/KACY. Slight chance of a rain
show near KRDG in the afternoon, otherwise no significant
weather expected. Easterly winds around 5-10 kt. Moderate
confidence.

Outlook...

Monday night through Tuesday... Mainly VFR, but sub-VFR conditions
possible with a few showers.

Tuesday night through Thursday...Periods of MVFR or IFR in SHRA.

Thursday night through Friday...Mainly VFR conditions expected.
-- End Changed Discussion --

&&

.MARINE...
Small Craft Advisories remain in effect for the ocean waters through
tomorrow, primarily for 4 to 6 ft seas. NE winds will generally
average 10 to 20 kts.

Sub-SCA conditions for Delaware Bay. Mainly NE winds around 10 to 15
kts.

Outlook...

Monday night through Tuesday...SCA in effect for the ocean waters,
mainly for elevated seas.

Tuesday night through Thursday...SCA may be needed for elevated seas
into the middle of next week.

Friday...Conditions likely below SCA criteria.

Rip currents...

There is a HIGH risk for the development of dangerous and life
threatening rip currents at the Jersey Shore and at Delaware Beaches
through Tuesday. Persistent onshore flow will continue with NE to E
winds of 10 to 20 mph with gusts up to 25 mph along with 3 to 6 ft
breaking waves.

Rip currents occur often in the vicinities of jetties and piers and
the speed of the currents are generally maximized at low tides.

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

&&

.TIDES/COASTAL FLOODING...
A prolonged period of onshore flow has resulted in, and will
continue to result in, a piling up of water along the coasts with
this water unable to drain within tidal waterways. Although
headlines are in effect through the Monday afternoon/night high tide
cycles, additional Coastal Flood Advisories may be needed for the
Tuesday afternoon/night high tide cycles.

For the Atlantic Coast, southern Raritan Bay, and Delaware Bay,
Coastal Flood Advisories remain in effect through the Monday
afternoon high tide cycles. A Coastal Flood Advisory may be needed
for some locations for the Tuesday afternoon high tide cycle.

For the tidal Delaware River, Coastal Flood Advisories remain in
effect through the Monday evening high tide cycle for minor coastal
flooding. A Coastal Flood Advisory may be needed for some locations
for the Tuesday evening high tide cycle.

For the northeastern shore of Maryland, Coastal Flood Advisories
remain in effect through the Monday night high tide cycles for minor
coastal flooding. A Coastal Flood Advisory may be also needed for
the Tuesday night high tide cycle.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory until 10 PM EDT Monday for PAZ070-071-
     106.
NJ...Coastal Flood Advisory until 6 PM EDT Monday for NJZ016.
     Coastal Flood Advisory until 5 PM EDT Monday for NJZ012>014-
     020>027.
     High Risk for Rip Currents through Tuesday evening for NJZ014-
     024>026.
     Coastal Flood Advisory until 10 PM EDT Monday for NJZ017>019.
DE...Coastal Flood Advisory until 6 PM EDT Monday for DEZ001.
     Coastal Flood Advisory until 5 PM EDT Monday for DEZ002>004.
     High Risk for Rip Currents through Tuesday evening for DEZ004.
MD...Coastal Flood Advisory until 5 AM EDT Tuesday for MDZ012.
     Coastal Flood Advisory until 2 AM EDT Tuesday for MDZ015-019-
     020.
MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ450>455.

&&

$$

SYNOPSIS...AKL/MPS
NEAR TERM...DeSilva/Kruzdlo
SHORT TERM...AKL
LONG TERM...AKL
AVIATION...AKL/DeSilva/Kruzdlo
MARINE...AKL/Kruzdlo/Wunderlin
TIDES/COASTAL FLOODING...Wunderlin