873
FXUS61 KPHI 032135
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
535 PM EDT Mon Jun 3 2024

.SYNOPSIS...
Surface high pressure over the area slides offshore by
Wednesday and moves out to sea on Thursday. A weak disturbance
passes through the region tonight, and then low pressure passes
through on Thursday. An upper trough sets up over the Northeast
for the end of the week and through next weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...
A relatively nice start to the nice week is ongoing as
temperatures are in the low to mid 80s under partly cloudy
skies. A sea and bay breeze is visible on radar. This will be
the focus point for any showers/thunderstorms this afternoon. We
have already seen some convective initiation in southern
Delaware, and would expect more near the Central and Southern
New Jersey coasts later this afternoon. However, expecting
storms to remain sub-severe as effective shear is less than 20
kt. Better instability is over the Delmarva peninsula right now
as well, which explains why storms have already started to fire
up down that way. 19z mesoanalysis shows around 1500-2000 J/kg
of SBCAPE over the Delmarva peninsula with around 1000-1500 J/kg
over the NJ Coastal Plain. With weak shear however, just
expecting to thunderstorms to develop and quickly collapse.
There is some DCAPE, currently around 600-800 J/Kg, so we could
see a stronger downburst this afternoon, but not overly
concerned this afternoon with convection. Outside of Delmarva
and the NJ coastal plain, it will be dry.

For tonight, high pressure begins to slide in from the north,
resulting in a weak onshore flow developing. Some patchy fog is
expected, mainly in areas near/along the coast. Otherwise, it
will be a quiet night with temperatures in the low to mid 60s.

For Tuesday, a ridge axis slides overhead with high pressure in
control at the surface. Should be a nice and quiet day overall.
With the weak onshore flow, areas near the coast will stay in
the 70s. Elsewhere, expect low to mid 80s.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Upper level ridge over the area Tuesday night will flatten out
on Wednesday. Meanwhile, a nearly vertically stacked area of low
pressure over central Canada will dig down into the upper
Midwest and Great Lakes. A trough develops out ahead of this,
and weak surface low pressure develops over the Mid-Atlantic and
Northeast. Scattered showers and thunderstorms develop by
Wednesday afternoon, with showers becoming likely late in the
day for the eastern shores of Maryland. Dew points rise well
into the 60s, so there could be a locally heavy downpour or two
in the afternoon.

Low pressure then passes over the area Wednesday night,
departing Thursday afternoon. Will carry likely PoPs for the
region during this time. There may be enough instability for
thunderstorms as well, so will keep chance for thunderstorms.

Highs will be in the lower 80s both Wednesday and Thursday,
though Thursday may be a degree or two warmer, depending on when
rain ends and skies clear out. But it will be fairly humid with
dew points well in the 60s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Surface low pressure moves out to sea Thursday evening. A cold
front approaches from the northwest as a closed upper low builds
down into the Great Lakes, Ohio Valley, and Northeast. This
closed low will park over the Northeast through the weekend,
possibly starting to depart on Monday.

Several waves of shortwave energy will rotate through the
trough. While this timeframe does not look to be a washout,
there will be chances for showers and thunderstorms each day.
Best chances for convection will be during the afternoon hours,
when peak heating will allow for highest instability.

High temperatures during this period will generally be at or
just shy of normal, topping off in the upper 70s to around 80.
Lows will be in the 50s to around 60.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...Prevailing VFR conditions with scattered clouds. Chance
(30%) of a shower/thunderstorm through 00z around KACY/KMIV.
Brief period of sub- VFR conditions possible with a stronger
storm. Winds 5 kt or less out of the west/northwest. Moderate
confidence.

Tonight...VFR to start though some patchy fog around KMIV/KACY
could bring visibility restrictions down to IFR. Fog develops
after 06z. Everywhere else should stay VFR though cannot rule
out some visibility at KRDG with patchy fog (20% chance). Winds
generally light and variable 5 kt or less, though an
east/southeast direction will be favored. Moderate confidence
overall.

Tuesday...Any restrictions lift back to VFR by 12z-13z. VFR
through the day. Winds out of the east around 5 kt. High
confidence.

Outlook...

Tuesday night...VFR.

Wednesday through Thursday...Restrictions likely in
SHRA/scattered TSRA.

Friday through Saturday...Primarily VFR, but scattered
SHRA/TSRA could result in brief restrictions.

&&

.MARINE...
No marine headlines expected through Tuesday. Winds out of the
east/southeast at 10 kt or less with seas around 2 feet. 20-30%
chance of showers/thunderstorms this afternoon off the coast of
southern NJ and Delaware.

Outlook...

Tuesday night...Sub-SCA conditions. Fair weather.

Wednesday through Thursday...Primarily sub-SCA conditions,
though occasional gusts to 25 kt are possible. VSBY restrictions
likely in showers, and scattered thunderstorms possible as
well.

Friday through Saturday...Sub-SCA conditions. Scattered showers
and thunderstorms, mainly during the daytime hours.

Rip Currents...

A LOW risk for the development of rip currents is in place for
Tuesday. Winds will be on onshore, but only around 10 MPH, with
1-2 foot waves and a short to medium period, resulting in the
low risk.

For Wednesday, winds increase to 10-15 mph but winds will be
less directly onshore. Combined with continuing 1 to 2 foot
waves and short to medium period keeps the overall risk for rip
current development at LOW.

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

Rip currents occur often in the vicinities of jetties and
piers. Utilize any guarded beaches if venturing out into the
water.

&&

.TIDES/COASTAL FLOODING...
With the return of sustained onshore flow and the approaching
New Moon on Thursday, there is also a return of the threat for
tidal flooding for much of our coastal region. The threat will
begin with the evening high tide on Tuesday, though primarily
spotty minor flooding is expected as the onshore winds will be
relatively weak around 10 mph. Cannot completely rule out some
widespread minor flooding if winds are a bit stronger. For
Wednesday and Thursday, the threat for widespread minor flooding
looks to increase as winds strengthen on Wednesday then turn
and become shore parallel on Thursday, potentially trapping
water along the coast. As of now, no coastal flooding headlines
have been issued but we will continue to monitor the coming high
tides and make adjustments to the forecast accordingly.

Overall, the threat for tidal flooding appears to be lower along
the Chesapeake Bay than elsewhere in the region but by the
early morning high tide Thursday, water levels may also approach
spotty minor.

&&

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

&&

$$

SYNOPSIS...MPS
NEAR TERM...Hoeflich
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...Hoeflich/MPS
MARINE...AKL/Hoeflich/MPS
TIDES/COASTAL FLOODING...AKL