710
FXUS61 KPHI 230824
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
424 AM EDT Sun Jun 23 2024

.SYNOPSIS...
High pressure remains in place through today bringing the
heat. A strong cold front comes approaches later today, moving
offshore by Monday morning. High pressure settles in for the early
part of the week before another cold front moves in for the middle
of the week. High pressure returns for the end of next week.



&&

.NEAR TERM /THROUGH TONIGHT/...
Temperatures remain rather uncomfortable early this morning, with
many locations across the urban corridor still in the upper 70s to
low 80s with dew points lingering in the muggy low 70s.

Oppressively hot and humid conditions remain for Sunday. Excessive
Heat Warnings remain in effect for the urban corridor and parts of
the NJ Coastal Plain as heat indices of 105-110 are expected.
Hunterdon County was upgraded to an Excessive Heat Warning this
morning. These conditions combined with the nearly week long stretch
of heat, are going to result in dangerous conditions outside for
Sunday as the effects of heat stress on the body can be cumulative.
Time outside should be limited and if you are out and about, drink
plenty of water!

With such a hot and humid airmass in place, and an approaching cold
front, there will be the chance for some severe weather. Lift will
be aided with a shortwave and pre-frontal trough coming into a moist
and unstable airmass. Deep layer shear of 30-40 kt,  moderate
instability (1000-2000 J/kg of SBCAPE), and DCAPE values in excess
of 1000 J/kg will support the development of several thunderstorms
capable of producing damaging wind gusts. SPC outlook for today has
upgraded our entire area to a Slight Risk for severe weather. The
limiting factor is the better shear will be located further north,
but there is still sufficient shear to support some strong to severe
thunderstorms. Forecast soundings do show some favorable veering
wind profiles as well, especially in the low levels (0-3km). As a
result, while the overall deep layer shear is not overly favorable
for tornadoes, we can`t rule out a brief tornado as a result of low-
level shear profiles.

For the flash flood risk, WPC has place a Marginal Risk for
Excessive Rainfall today across much of the forecast area. With
PWATs pushing 2 inches, any thunderstorms will produce heavy rain
capable of dropping an inch or two of rain quickly and result in a
localized flash flood risk. That said, storm motions are expected to
be more progressive today thanks to the advancing cold front, but
some training thunderstorms are still possible if conditions are
just right.

Thunderstorms are expected to persist into the evening, though
becoming less severe throughout the night, before gradually being
swept offshore overnight as the cold front moves in late Sunday
night/early Monday morning. Behind the front, temperatures are
expected to fall into the low to mid 70s with dew points dropping
into the 60s before daybreak.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
The much anticipated cold front gradually pushes offshore through
Monday. Some lingering showers/isolated thunderstorms could hang
around the coast through the morning, but not expecting much from
that. The cold front will knock temperatures down towards more
seasonal levels with dew points crashing into the 50s. This will
bring some much needed relief and Sunday will be the last day for
the heat headlines. Other than the morning showers near the coast,
it will be a nice day with temperatures in the mid to upper 80s and
even some 70s in the higher elevations of northern NJ and southern
Poconos. The only thing to note is that there will be a bit of a
tight gradient in the wake of the front, with some wind gusts in the
20s possible.

High pressure begins to work in for Monday Night with mostly clear
skies anticipated. Winds diminish after sunset. Temperatures will
drop into the low to mid 60s, with upper 60s within urban areas.


&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Above normal temperatures will continue for the long-term, however
most of next week with the exception of Wednesday will not be as
oppressive as the heat this weekend. High temperatures through most
of the extended look to be in the upper 80s/low 90s. The exception
being Wednesday, as high pressure moves offshore resulting in a
southerly flow and warm air advection. This will bring temperatures
towards the low to mid 90s and heat index values near 100. Will
likely need a Heat Advisory for some areas, but want to get through
this weekend`s heat before moving on to next week.

It will be a mostly dry week as high pressure and ridging aloft will
be in control for Tuesday into Wednesday morning. A cold front will
approach for Wednesday, bringing some scattered showers and
thunderstorms to the region for the Wednesday PM to Thursday
timeframe. Am a bit concerned on the hydro side of things as the
front looks to be a little on the slower side, and we will have a
very warm and moist airmass in place. With such a warm and moist
airmass in place, cannot rule out some stronger thunderstorms as
well. However, the area could use some rain. Will continue to
monitor over the next few days, but this system is really the only
impactful thing in the extended other than the Wednesday heat.

We dry out by late Thursday once the front passes. The cold front
will knock down temperatures a few degrees with a more comfortable
airmass ushering in as dew points fall back into the 50s. Back end
of the long-term looks dry as an upper level ridge approaches from
the west with an expansive area of high pressure passing either
overhead or just to the north.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Early this morning (through 12Z)...VFR, however some localized fog
possible late. Southwest winds 5-10 knots, becoming locally light
and variable. Winds will become north or northeast 5-10 knots for
some terminals where an outflow boundary moves through. Low
confidence on the details.

Sunday...Some showers and thunderstorms in the afternoon will result
in times of local sub-VFR conditions and gusty winds. Southwest
winds increasing to 10-15 knots with gusts 20-25 knots. Moderate
confidence.

Sunday night...Restrictions likely with showers and thunderstorms
(60-80%).

Outlook...

Monday..Some lingering showers (20-30%) possible at KACY/KMIV but
all sites should be back to VFR by midday. Gusty northwest winds up
to 25 kt expected at all sites.

Monday Night through Tuesday Night...VFR. No significant weather.

Wednesday through Thursday...Periods of sub-VFR conditions likely
(60-80%) with showers and thunderstorms moving through at times.

&&

.MARINE...
Small Craft Advisory conditions develop for the coastal waters this
morning with winds and seas building into the afternoon and evening.
SW winds will ramp up this morning and gust to 25-30 kts by the
afternoon before gradually diminishing to 25 kts late tonight. Seas
will build to 5-7 feet by late afternoon as well and remain elevated
through the nighttime hours.

Outlook...

Monday...Small Craft Advisory remains in effect through Monday as
seas will be near 5 feet. Winds out of the northwest will be around
10-20 kt.

Monday Night through Wednesday...No marine headlines expected.


Rip Currents...

Sunday...With south winds 15 to 25 mph, breaking waves in the 3
to 5 foot range, and a 6 to 8 second wave period, we are
running with a HIGH risk for the development of rip currents for
Cape May/Atlantic/Ocean County and a MODERATE risk for Monmouth
and Sussex, DE beaches. Low tide is mainly in the mid
afternoon.

Monday...Winds relax a bit and back offshore, but wave periods
are forecast to increase. This said, with west winds 10 to 15
mph (maybe some gusts up to 20 mph across the northern beaches),
breaking waves in the 2 to 4 feet range, and a 6 to 8 second
wave period, we are running with a MODERATE risk for the
development of rip currents everywhere. Low tide is mainly in
the mid to late afternoon.

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

&&

.CLIMATE...
Record high temperatures Sunday.

Location          Record High (6/23)

Philadelphia, PA      97/1888
Allentown, PA         95/1965
Reading, PA           96/1908
Mount Pocono, PA      90/1908
Trenton, NJ           97/1894
AC Airport, NJ        98/1988
AC Marina, NJ         91/1909
Wilmington, DE        100/1894
Georgetown, DE        100/1988

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Excessive Heat Warning until 8 PM EDT this evening for PAZ070-
     071-102-104-106.
     Heat Advisory until 8 PM EDT this evening for PAZ054-055-
     060>062-101-103-105.
NJ...Excessive Heat Warning until 8 PM EDT this evening for NJZ009-
     010-012-013-015>020-027.
     Heat Advisory until 8 PM EDT this evening for NJZ014-021>026.
     Heat Advisory until 8 PM EDT this evening for NJZ001-007-008.
     High Risk for Rip Currents from 8 AM EDT this morning through this
     evening for NJZ024>026.
DE...Excessive Heat Warning until 8 PM EDT this evening for DEZ001.
     Heat Advisory until 8 PM EDT this evening for DEZ002>004.
MD...Heat Advisory until 8 PM EDT this evening for MDZ012-015-019-
     020.
MARINE...Small Craft Advisory from 8 AM this morning to 6 PM EDT Monday
     for ANZ450>455.

&&

$$

SYNOPSIS...Hoeflich
NEAR TERM...MJL
SHORT TERM...Hoeflich
LONG TERM...Hoeflich
AVIATION...Hoeflich/MJL
MARINE...Hoeflich/MJL
CLIMATE...NWS PHI