009
FXUS61 KPHI 110736
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
336 AM EDT Tue Jun 11 2024

.SYNOPSIS...
High pressure will retreat offshore through the middle of the
week. Temperatures will begin to rebound through Friday ahead of
a cold front, which will bring a chance of showers and storms
across the region. With the front offshore by Saturday, high
pressure will build into the region again through the weekend
with temperatures rebounding to well above normal into early
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Weak wave of low pressure bringing a band of showers and
embedded thunder across the Delmarva and far southern NJ early
this morning should be departing off the coast before dawn.
Further north, partly to mostly cloudy and seasonably cool with
temps in the 50s to low 60s.

For today, most of the area starts out quiet and dry with some
sun. However, with closed low developing just to the north and
plenty of vorticity rotating around, combined with the cold pool
aloft and strong June insolation, and we`ll likely see a lot of
cumulus to stratocumulus by midday. A lot of guidance also hits
on sea-breeze front helping spawn some showers and isolated
thunderstorms by this afternoon, starting out mostly over NJ and
DE but possibly migrating inland toward SE PA. So, have chance
POPs across much of the region for the PM, but further NW, looks
like the Lehigh Valley, Berks and Poconos are more likely to
stay dry. Temps will be rather cool for mid-June, with 70s
common.

Tonight, upper low starts migrating back to the northeast and
heights rise rapidly. This should cause lingering convection to
die quickly before sunset with mostly clear to partly cloudy
skies overnight. Lows mostly in the 50s to low 60s. Enjoy it, as
we`re about to flip the page to summer in a big way.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
The early week troughing will be offshore by early Wednesday,
and quasi-zonal flow will develop in its wake through the end of
the week with increasing heights and thicknesses. Another trough
axis will approach the region late Friday. At the surface, broad
high pressure will shift offshore through the end of the week
with surface flow turning toward the south/southwest.

This pattern will translate to increasing temperatures and
dewpoints with each passing day as well as a dry forecast until
Friday. Following a return to near normal temperatures with
highs in the low 80s on Wednesday, highs will increase to near
90 degrees in most inland locations on Thursday. On Friday,
widespread inland high temperatures in the low to mid 90s are
forecast ahead of the approaching cold front. While dewpoints
will be on the rise, they should top out in the low to mid 60s.
This means that heat indices will be close to the air
temperatures. Nevertheless, we will be close to early season
Heat Advisory criteria within the Philly urban/metro area on
Friday.

Some limiting factors for Friday`s heat could be the increasing
cloud cover ahead of the could front, plus the arrival of
showers and thunderstorms later in the day. Convective details
remain unclear at this time, but the medium range guidance
continues to indicate potential for at least some isolated to
scattered showers and thunderstorms along and ahead of the front
Friday afternoon and evening. With the approaching trough,
there will be at least modest shear and forcing for convection.
These could also be sufficient enough for a severe threat as
well, however the limiting factor for severe currently appears
to be the less-than-impressive instability thanks to the poor
mid-level lapse rates. In any case, we`ll need to keep a close
eye on Friday`s heat and severe weather threats. `Tis the
season!

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
Friday`s trough will be pushing offshore on Saturday, then some
rather expansive ridging will begin to build across the eastern
CONUS into early next week. At the surface, high pressure will
build into the region through the weekend before moving offshore
into early next week. The high pressure will provide the area
with a return to more seasonable temperatures and humidity for
Father`s Day weekend following the late week heat, with highs in
the mid 80s both Saturday and Sunday under mostly sunny skies.

With the high pressure offshore, southwesterly surface flow and
the building ridging aloft will result in increasing
temperatures into early next week. Current indications are that
we could see a multi-day heat wave, impacting much of next week
with high temperatures in the low to mid 90s across much of the
area, along with little chances for convection. The current CPC
Week 2 outlook indicates a roughly 70% chance of above normal
temperatures for our region encompassing next week.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Through 12Z...VFR. Scattered showers and maybe a thunderstorm
approaching KACY/KMIV but impacts unlikely. Winds north to
northwest 5 kts or less. High confidence.

Today...VFR overall. Scattered, mainly afternoon showers may
impact all terminals except KRDG/KABE, with an isolated t-storm
possible as well, most likely at KMIV. A heavier storm could
briefly reduce vsby to MVFR or even IFR, but it should be very
transient should it occur. Winds north to northeast, becoming
southeast for KMIV/KACY in the afternoon and NW for remaining
terminals, generally 5 kts or less. Moderate confidence.

Tonight...VFR. Winds becoming NW 5 kts or less. High
confidence.

Outlook...

Wednesday/Thursday...VFR. No significant weather expected.

Friday...Prevailing VFR conditions, however there is a 30-50%
chance of TSRA impacting the terminals, mainly between 18Z-06Z.

Saturday...VFR. No significant weather expected.

&&

.MARINE...
No marine headlines thru tonight. Winds generally below 10 kts.
Seas 1-2 ft. An isolated thunderstorm possible, mainly this
afternoon.

Outlook...

Generally sub-SCA conditions from Wednesday into early Thursday
with fair weather. For the afternoon and evening periods Thursday
and Friday, gusts nearing 25 kts and near 5 ft seas are
possible, along with scattered showers/tstms Friday afternoon
and evening. Fair weather Sat/Sun.

Rip Currents...

Low risk of rip currents in place for today and Wednesday.
Winds will be onshore today, but with winds weak, and a short to
medium period swell combined with 1 to 2 foot breakers, there
is a low risk for rip currents. Similar conditions on Wednesday,
though winds go more shore parallel, still less than 10 MPH.

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

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Staarmann
NEAR TERM...RCM
SHORT TERM...Staarmann
LONG TERM...Staarmann
AVIATION...RCM/Staarmann
MARINE...RCM/Staarmann