147
FXUS61 KPHI 220539
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
139 AM EDT Sat Jun 22 2024

.SYNOPSIS...
Bermuda high pressure remains in control through much of the weekend.
A front is forecast to remain just to our north through Sunday,
however a stronger cold front will then cross our area Monday.
High pressure returns for Tuesday followed by another front for
the middle of next week.

&&

.NEAR TERM /THROUGH TODAY/...
As of 130 AM, evening convection has gradually fizzled out,
though a few showers and a rumble of thunder remain across the
Poconos and Lehigh Valley. We could see some additional showers
or a thunderstorm develop over the next few hours, but coverage
is expected to gradually lessen through the early morning hours.

Otherwise, a very warm and muggy night on tap tonight with lows
primarily in the low to mid 70s. Patchy fog is possible
overnight mainly where some rain occurred this evening.

For Saturday, the overall pattern/situation remains the same as
the hot conditions continue. With confidence growing as we get
closer to the day and temperatures having come down just a bit
in spots spots, went with a Heat Advisory for the I-95 corridor
to the north and west; no other changes made besides that. The
I-95 sites will likely see the mid to upper 90s as highs, but
heat indices will likely stay in advisory criteria. Basically,
the same shower and thunderstorm situation seen for today will
repeat for Saturday afternoon into Saturday night.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
The heat wave will continue into the short term, then some break in
the heat Monday following a cold front which moves through. The heat
headline, excessive heat watch, for Sunday will continue with highs
in the mid 90s widespread and some chance for upper 90s for the
urban areas. Heat index values in the 100-105 range expected for
Sunday. These temps will continue with high humidity too as deep
SW/S flow continues over the region. These remains some uncertainty
with regards to how much cloud cover and how fast it arrives. The
high temperature forecast may be affected by these factors.

More certainty is seen with regards to the precipitation forecast
as a front cuts through the heat and humidity creating good chances
for tstms Sunday/Sunday night. We will carry high chance and low
likely pops for the periods and continue with gusty winds/heavy
rainfall wording for now. The front moves offshore by Monday with
some lingering clouds/showers for NJ into Monday before improvement
from W to E Monday afternoon. High temps Monday will be in the mid
80s for the N/W areas and low 90s for srn NJ and Delmarva. Humidity
levels will decrease with a drier W/NW flow becoming established
over the area.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The upper high/ridge that has brought all the excessive heat to the
area this week and into the weekend will slowly lose its grip over
the northern Middle Atlantic region by early next week. Instead, we
will be closer to the westerlies (storm track) with the big high to
the SW and a weak mean trough across the Northeast. This means that
while we will still have the opportunity for a hot day (especially
Wed.) but we won`t be in another prolonged period of excessive
heat/humidity. Highs will largely favor the mid/upper 80s with a few
low 90s in the urban areas.

After the showers in the short term, the precipitation for the long
term will basically center on Wed./Wed night when a cold front and
upper trough cross the region. We will go with the 30-40ish (%) pops
offered by the NBM for now.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Rest of tonight (through 12Z)...VFR. South to southwest winds
5-10 knots, becoming locally light and variable at some
terminals. Moderate confidence.

Saturday...VFR, however some afternoon showers and thunderstorms
will be possible especially from near KTTN, KABE and KRDG.
Southwest winds increasing to near 10 knots, becoming south in
the afternoon mainly at KILG and KACY due to bay/sea breezes.
Moderate confidence.

Outlook...
Saturday night through Sunday night...VFR except in sct
showers/tstms when lower CIGS/VSBYS expected.

Monday...Morning lower clouds possible then VFR.

Tuesday...VFR.

Wednesday...Lower CIGS/VSBYS with scattered showers/tstms.

&&

.MARINE...
Marine headlines are not expected through Saturday. Later on
Saturday however, wind gusts are expected to increase to around
20 kts with building seas across the ocean waters. The northern
New Jersey coastal waters may flirt with some 5 foot seas by
later in the afternoon.

Outlook...

Saturday night... Increasing winds/seas. Low-end SCA seas
develop late. Fair most areas but a few tstms for North NJ
waters.

Sunday...SCA possible with enhanced winds/seas in scattered
tstms.

Monday and Tuesday...Mostly sub-SCA. Fair after a few morning
showers Monday.

Rip Currents...

Saturday...South winds around 10-15 mph and breaking waves around
2 feet expected. Portions of the southern New Jersey coast will
maintain an onshore component of the wind, in addition to being
1 day removed from the Full Moon. As a result, have kept a
MODERATE Risk for all New Jersey beaches except Monmouth County.
For the Delaware Beaches and Monmouth County, have kept a LOW
Risk of dangerous rip currents.

Sunday...Southerly winds will increase from 10 mph in the
morning to 20 mph in the afternoon with breaking waves around 2
to 4 feet. Due to increasing winds and higher seas along the
shore, decided to go with a MODERATE Risk for dangerous rip
currents for all NJ/DE beaches. May need to evaluate the
potential for a HIGH Risk of rip currents for southern New
Jersey beaches in future updates.

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

&&

.CLIMATE...
Record high temperatures Saturday.

Location          Record High (6/22)

Philadelphia, PA      100/1988
Allentown, PA         95/1941
Reading, PA           96/1921
Mount Pocono, PA      90/1908
Trenton, NJ           99/1988
AC Airport, NJ        100/1988
AC Marina, NJ         92/1949
Wilmington, DE        98/1988
Georgetown, DE        97/2012

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...Heat Advisory until 6 AM EDT Sunday for PAZ054-055-060>062-070-
     071-101>106.
     Excessive Heat Watch from Sunday morning through Sunday
     evening for PAZ054-055-060>062-070-071-101>106.
NJ...Heat Advisory until 6 AM EDT Sunday for NJZ001-007>010-012-013-
     015>020-027.
     Excessive Heat Watch from Sunday morning through Sunday
     evening for NJZ001-007>010-012>027.
DE...Heat Advisory until 6 AM EDT Sunday for DEZ001.
     Excessive Heat Watch from Sunday morning through Sunday
     evening for DEZ001>004.
MD...Excessive Heat Watch from Sunday morning through Sunday
     evening for MDZ012-015-019-020.
MARINE...None.

&&

$$

SYNOPSIS...MPS/OHara/Wunderlin
NEAR TERM...Gorse/MJL/Wunderlin
SHORT TERM...OHara
LONG TERM...OHara
AVIATION...Gorse/MJL/OHara/Wunderlin
MARINE...DeSilva/Gorse/OHara/Wunderlin
CLIMATE...