832
FXUS61 KPHI 210140
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
940 PM EDT Thu Jun 20 2024

.SYNOPSIS...
Bermuda high pressure remains in control through much of the
weekend. A back door cold front will move in from the north on
Friday and will stall over the area into Saturday before
returning north as a warm front. A stronger cold front will
approach the region Sunday looking to pass through Monday. High
pressure returns for Tuesday, followed by another front for
Wednesday or Thursday.

&&

.NEAR TERM /THROUGH FRIDAY/...
The Heat Advisory will continue through the near term. Heat and
humidity are expected to increase on Friday resulting in a
growing number of heat indicies in the upper 90s to near 100
degrees. Overnight lows will be in the mid to upper 60s for most
with the lower 70s across the most urban environments.

The forecast area will be precipitation free through the
overnight and into early Friday afternoon. High temperatures are
forecast to range from the low to mid 90s away from the
immediate coast and outside of higher terrain. Friday will
likely be the hottest and most humid day of the ongoing heatwave
so far.

A backdoor cold front will approach from the north and provide
a focus for showers and thunderstorms north of I-195 in NJ and
the PA Turnpike. Slow- moving thunderstorms will likely produce
heavy rain and localized flooding, especially the farther north
one goes. Localized severe thunderstorms will be capable of
damaging wind gusts. The Storm Prediction Center has a Marginal
Risk (Level 1 out of 5) for near and north of I-78, where the
greatest threat for localized damaging winds from microbursts is
possible. Some remnant showers and storms could make a run at
the I-95 corridor later in the evening, however these will
likely be weakening and diminishing in coverage.

Showers and thunderstorms will be slow moving because the
nature of winds will be on the lighter side. Expect S to SW
winds around 5-10 mph with the exception of the immediate coast
and bays where sea/bay breezes will turn more SE and gust to 15
or 20 mph Friday afternoon.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
The short term forecast will be dominated by hot and stormy
conditions. An Excessive Heat Watch remains in effect for both
Saturday and Sunday. No significant changes to the Excessive
Heat Watch at this time.

A cold frontal boundary over or just north of the region Friday
night is expected to stall some with time. Come Saturday into
Sunday, this boundary is expected to lift northwards of the
region as a warm front, advecting even warmer air into the
region. For Sunday, a cold front from the northwest will
approach with time, but will not look to cross through until
around the Monday time frame.

Overall, a hot and stormy pattern will take hold for the
weekend given the synoptic situation. First, chances for showers
and thunderstorms will continue into Friday night due to the
proximity of the stalling front and some shortwave energy.
Thunderstorm potential will be greatest in the evening and will
taper off with time. Currently, the SPC maintains our northern
and northwestern most areas outlooked in a MARGINAL risk for
severe weather, with gusty winds being the primary concern. Some
patchy fog could develop across the region during the overnight
into morning hours, especially for areas that previously saw
showers and thunderstorms.

Strong warm air advection will take hold for Saturday through
Sunday bringing the region the warmest temperatures seen so far
during this ongoing heat wave. The interior areas and I-95
corridor could see the mid to just upper 90s Saturday with
temperatures ~2-4 degrees warmer for Sunday. The greatest chance
for many of our areas to hit Excessive Heat Warning criteria
will be Sunday. Opted to not change headlines at this time given
the stormy nature of the forecast; clouds and
showers/thunderstorms could prevent heat index values necessary
of warning criteria from being reached. Showers and
thunderstorms again possible Saturday afternoon and evening, but
mainly sub-severe conditions expected at this point. There is a
growing concern for severe weather for the Sunday afternoon
into Sunday night time frame with the approach of the stronger
cold front. Currently, the SPC does not have us outlooked for
any severe weather potential during this time frame.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Unsettled and somewhat uncertain long term appears to be on
tap. A cold front looks to continue approaching Sunday night
crossing through sometime Monday. Afterwards, surface high
pressure begins to build back in holding a firm grasp over the
region for Tuesday. Ensembles suggest another cold front could
approach the region from the northwest on Wednesday. This front
could cross through sometime during the Wednesday/Thursday time
frame.

Overall, the pattern suggests a fairly unsettled long term is
on the horizon. Showers and thunderstorms should be anticipated
Sunday night with the approach of the cold front. Shower and
thunderstorm potential could linger through Monday with the cold
frontal passage. No showers and thunderstorms anticipated for
Tuesday with surface high pressure in control. More chances for
showers and thunderstorms Wednesday/Thursday with the next
frontal approach and passage.

Temperatures mainly in the 90s look to continue into Wednesday
at this point. Heat headlines may continue into the week.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...VFR with mostly clear skies. Southwest winds around 5
kt becoming light and variable at times. High confidence.

Friday...Mainly VFR with mostly clear skies. A late afternoon
SHRA/TSRA with sub-VFR conditions possible near KABE, otherwise
no significant weather expected. South-southwest winds around
7-12 kt, locally higher. High confidence.

Outlook...

Friday night...Sub-VFR conditions possible with SHRA/TSRA
followed by patchy fog development. Moderate confidence.

Saturday...Mainly VFR. Some SHRA/TSRA anticipated in the
afternoon and evening. Moderate confidence.

Saturday night...Mainly VFR. Some SHRA/TSRA anticipated into
the first half of the period. Moderate confidence.

Sunday...Sub-VFR possible. SHRA/TSRA anticipated in the
afternoon and evening. Low confidence.

Sunday night...Sub-VFR possible. SHRA/TSRA anticipated into the
first half of the period. Low confidence.

Monday...Mainly VFR. Some SHRA/TSRA anticipated in the
afternoon and evening. Moderate confidence.

Tuesday...VFR. High confidence.

&&

.MARINE...
Rinse and repeat the next 24 hours. The trend this week has
been lighter winds in the morning and stronger winds in the
afternoon and evening. The same is expected tonight through
Friday. Guidance has been a bit high with speeds as an inversion
has been keeping them lower than the raw output suggests.
Reports of upwelling with this multi-day south wind event is
strengthening the inversion further. This said, no marine
headlines are expected through Friday. Southwest to southeast
winds 10-20 kt can be expected, with the highest speeds once
again across Monmouth and Ocean counties. Speeds may drop below
below 10 kt for a short time during the mid to late morning
hours. Seas will be 2 to 4 feet.

Outlook...

Friday night through Saturday...No marine headlines
anticipated. However, frequent gusts around 20 kts anticipated
at times.

Saturday night through Monday...SCA criteria anticipated. Seas
will build with time becoming 5-7 feet Sunday night before
diminishing.

Tuesday...No marine headlines anticipated.

Rip Currents...

Friday...Southerly winds around 10-15 mph and breaking waves
will be around 2-3 feet. Portions of the southern NJ coast will
keep an onshore component of the wind, in addition to the
occurrence of the Full Moon. For this reason, have maintained a
MODERATE Risk for all New Jersey beaches except Monmouth County.
For the Delaware Beaches and Monmouth County, maintained the
LOW Risk of dangerous rip currents.

Saturday...Similar weather conditions are expected on Saturday.
With this in mind, saw no reason to change Rip Risks for NJ/DE
beaches from what is currently posted for Friday.

Rip currents occur often in the vicinities of jetties and
piers. Utilize any guarded beaches if venturing out into the
water. For specific beach forecasts, visit weather.gov/beach/phi

&&

.CLIMATE...
Mount Pocono is the only site that could come close to its
record today. No other records are in jeopardy today based on
the forecast. No record high minimum temperatures will be set
today based on the temperatures observed this morning.

Location          Record High (6/20)

Philadelphia, PA      98/1931
Allentown, PA         100/1923
Reading, PA           101/1923
Mount Pocono, PA      89/2012
Trenton, NJ           98/1923
AC Airport, NJ        95/2012
AC Marina, NJ         90/1908
Wilmington, DE        97/2012
Georgetown, DE        98/2012

Record high temperatures Friday.

Location          Record High (6/21)

Philadelphia, PA      99/1923
Allentown, PA         100/1923
Reading, PA           99/1923
Mount Pocono, PA      90/1953
Trenton, NJ           97/1923
AC Airport, NJ        97/1988
AC Marina, NJ         94/2012
Wilmington, DE        98/2012
Georgetown, DE        99/2012

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 Saturday for PAZ054-055-060>062-
     070-071-101>106.
     Excessive Heat Watch from Saturday morning through Sunday
     evening for PAZ054-055-060>062-070-071-101>106.
NJ...Heat Advisory until 6 AM EDT Saturday for NJZ001-007>010-012-
     013-015>020-027.
     Excessive Heat Watch from Saturday morning through Sunday
     evening for NJZ001-007>010-012-013-015>020-027.
     Excessive Heat Watch from Sunday morning through Sunday
     evening for NJZ014-021>026.
DE...Heat Advisory until 6 AM EDT Saturday for DEZ001.
     Excessive Heat Watch from Saturday morning through Sunday
     evening for DEZ001.
     Excessive Heat Watch from Sunday morning through Sunday
     evening for DEZ002>004.
MD...Excessive Heat Watch from Sunday morning through Sunday
     evening for MDZ012-015-019-020.
MARINE...None.

&&

$$

SYNOPSIS...MPS/Wunderlin
NEAR TERM...DeSilva/Kruzdlo/Staarmann
SHORT TERM...Wunderlin
LONG TERM...Wunderlin
AVIATION...DeSilva/Kruzdlo/MPS/Wunderlin
MARINE...AKL/Kruzdlo/MPS/Wunderlin
CLIMATE...WFO PHI