065
FXUS61 KPHI 061314
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
914 AM EDT Sat Jul 6 2024

.SYNOPSIS...
High pressure dissipates offshore this evening. A cold front
slowly crosses the area through Sunday. High pressure returns
for Sunday night and Monday before another slow moving low pressure
system encroaches upon the area through the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 9:10am...The first round of showers/storms have exited
our area. Can see a remnant outflow boundary sinking southward
across North-Central NJ on satellite where some lingering
cloudiness remains. Otherwise, mostly clear skies are ongoing
across much of the area this morning.

A lull in the activity is present, before the next round of
showers and storms develops near/along the weak cold front
progressing into our region. The cold front is rather weak, and
there is weak forcing in the mid and upper levels. It`s possible
that the remnant outflow boundary could be a predecessor of
where storms initiate later this afternoon. Consequently, have
low confidence in the timing and location of this round of
showers and storms. Don`t trust hi- res guidance much in this
situation as many hi- res models struggle to depict weak forced
convection.

That being said, by the earliest we could reasonably expect the
second round, the main focus of surface convergence should be near
or east of the fall line. Consequently, reduced PoPs along and west
of the fall line for this afternoon and evening. This round of
showers and storms should gradually shift further south and east.
That being said, the front will likely stall out over our coastal
plains later today. Given the still very high precipitable water
values, any of the stronger storms today will be capable of heavy
downpours.

The other big weather story today is the continued heat and humidity.
Even with increased cloud cover likely tempering ambient temperatures
slightly, dewpoints will remain well into the 70s, especially for
areas along and east of the fall line, leading to widespread heat
index values above 100 F. For areas along and southeast of the urban
corridor, expect heat index values near or above 105 F. Thus, have
changed the heat advisory to an excessive heat warning in these locations.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Very typical early July weather with hot and humid days. The rain/tstm
chances will be determined by weak shortwaves and fronts that resolve
poorly with the convection-allowing models. There will be a small
chance for rains will be across the Southeast-most edge of our
CWA Sunday with the dissipating front across that area. Another
weak system approaches Monday, so chance pops for the NW areas
for (mostly) the afternoon and evening.

Still hot both days with upper 80s/low 90s for the area. The dew
points Sunday will be a little lower (60s for the N/W of I95
areas and low 70s SE), but higher humidity quickly returns for
Monday. We`ll probably remain below Heat Advisory criteria for
Monday, but closer to it Tuesday.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
We`ll gradually lose the influence of the upper ridge across the
region next week as it weakens and slides to the east. What that
means is that we`ll catch a break with the excessive heat and humidity
as the week progresses. Temperatures will be a little above normal
Tue/Wed, but then go a little below normal for Thu/Fri. The humidity
levels will probably not change too much with dew points in the
upper 60s/low 70s most spots. There are signs that the higher
temperatures may return next weekend. Sad.

As the high moves away several weaker systems will tend to move
through instead of getting steered away (around the high), so
we`ll have almost daily chances for showers/tstms thru the period.
As is typical in summer, the late afternoon and early evening time
periods are most favored. Tuesday will have the greatest chances
of rains with a weak front approaching the Middle Atlantic region.
That day will have some low likely range pops for the far NW and
chance pops elsewhere. Towards Friday, a slow moving front could
affect the area with some heavy rains. Too early to be confident
about that attm.

&&

.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Through today...A second round of SHRA and TSRA could develop
in the Delaware Valley (near KILG, KPHL, KPNE, and KTTN) between
16 and 20Z and progress eastward towards the coast, including
KMIV and KACY. However, there is low confidence in the timing
and extent of this second round. Outside of those exceptions,
prevailing VFR is expected. Winds, generally less than 10 kt,
will start prevailing S, but become more SW through the day. Low
confidence.

Tonight...Starting prevailing VFR. There is a small chance for
another round of low stratus, especially at KACY and KMIV after 06Z.
Winds gradually becoming NW, but speeds below 10 KT.
Moderate confidence on the overall pattern, but low confidence on
the potential for low stratus.

Outlook...

Sunday... Mostly VFR. Patchy rural fog at night.

Monday thru Wednesday... VFR except for morning low clouds or fog
around sunrise. Also, scattered showers/tstms mostly afternoon and
early evening with IFR/MVFR possible.

&&

.MARINE...
A Marine Dense Fog Advisory is now in effect for all marine
zones along the NJ coast until 1 PM this afternoon as dense fog
is present on all webcams along the coast. Seas remain around 5
ft and are expected through the day on the Atlantic coastal
waters, where a Small Craft Advisory remains in effect. Once
seas diminish late today, winds and seas should stay below SCA
criteria through tonight.

On the Delaware Bay, winds and waves should remain below SCA
criteria through tonight.

Outlook...

Conditions will remain below SCA limits with the greatest hazard
being scattered tstms during (mostly) the afternoon and evening
hours.

Rip Currents...

The effects of a New Moon today will linger into the weekend.
Today, south winds will average 10 to 15 mph with gusts up to
20 mph. With an onshore component in New Jersey, this results in
a MODERATE risk for the development of dangerous and life threatening
rip currents for the Jersey Shore. Since this direction is a
bit more parallel to the coast, if not a bit offshore, in Delaware,
this results in a LOW risk for dangerous rip currents at Delaware
Beaches.

On Sunday, winds will be lighter and a bit more onshore. This results
in a MODERATE risk for dangerous rip currents at the Jersey Shore,
mainly south of south of Monmouth county. For Monmouth county and
Delaware Beaches, there is a LOW risk for the development of dangerous
rip currents.

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

&&

.TIDES/COASTAL FLOODING...
With the New Moon to occur today, some locations may see some
spotty minor coastal flooding during the next few high tide
cycles.

&&

.CLIMATE...
Near record breaking warmest low temperatures are forecast today.
Records for our climate sites are listed below:

Record Warmest Low Temperatures
                           July 6
Site                  Record/Year
Allentown (ABE)           74/1999
AC Airport (ACY)          76/1999
AC Marina (55N)           80/1999
Georgetown (GED)          78/2012
Mount Pocono (MPO)        71/1999
Philadelphia (PHL)        79/1999
Reading (RDG)             75/1934
Trenton (TTN)             76/1999
Wilmington (ILG)          77/1999

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Excessive Heat Warning until 8 PM EDT this evening for PAZ070-
     071-104-106.
     Heat Advisory until 8 PM EDT this evening for PAZ060>062-
     101>103-105.
NJ...Excessive Heat Warning until 8 PM EDT this evening for NJZ010-
     012-013-015>023-027.
     Heat Advisory until 8 PM EDT this evening for NJZ001-007>009.
     Air Quality Alert from 11 AM to 11 PM EDT Sunday for
     NJZ008>010-012>015-017>020-026-027.
DE...Excessive Heat Warning until 8 PM EDT this evening for
     DEZ001>003.
MD...Excessive Heat Warning until 8 PM EDT this evening for MDZ012-
     015-019-020.
MARINE...Dense Fog Advisory until 1 PM EDT this afternoon for
     ANZ450>453.
     Small Craft Advisory until 8 PM EDT this evening for
     ANZ450>455.

&&

$$

SYNOPSIS...DeSilva/Johnson
NEAR TERM...DeSilva/Johnson
SHORT TERM...OHara
LONG TERM...OHara
AVIATION...Johnson/OHara
MARINE...DeSilva/Johnson/OHara
TIDES/COASTAL FLOODING...WFO PHI
CLIMATE...WFO PHI