379
FXUS61 KPHI 202123
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
523 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 this forecast period. We`re
seeing apparent temperatures in the mid 90s this afternoon with some
upper 90s. The heat will increase tomorrow resulting in a growing
number of apparent temperatures in the upper 90s. 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 tomorrow morning and early afternoon. A backdoor cold front
will approach from the north tomorrow and provide a focus for
showers and thunderstorms north of 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 (1 out of 5)
for portions of the southern Poconos, northern New Jersey, and
Lehigh Valley.

Showers and thunderstorms will be slow moving because winds will be
on the lighter side. The same goes for surface winds. Expect S to SW
winds 5 to 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 /22Z THURSDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...VFR. Southwest winds 5 kts or less. High confidence.

Friday...Mainly VFR. A late afternoon SHRA/TSRA with sub-VFR
conditions possible (only 20 to 30% chance) at KRDG, KABE, and KTTN.
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 tomorrow. Models have
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 tomorrow.
Southwest to southeast winds 10-20 kts can be expected, with the
highest speeds once again across Monmouth and Ocean counties. Speeds
may drop below below 10 kts 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...Kruzdlo
SHORT TERM...Wunderlin
LONG TERM...Wunderlin
AVIATION...Kruzdlo/MPS/Wunderlin
MARINE...AKL/Kruzdlo/MPS/Wunderlin
CLIMATE...WFO PHI