063
FXUS61 KPHI 021925
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
325 PM EDT Tue Jul 2 2024

.SYNOPSIS...
High pressure builds in through this evening before moving offshore
Wednesday. A more active period begins Thursday with the arrival of
a surface trough, bringing hot and humid conditions along with
chances for showers and storms each day into the weekend. A frontal
boundary may linger across the region into early next week, with
generally unsettled conditions persisting.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Tonight, high pressure will remain across the region. Skies will be
clear except for some occasional Ci/Cs clouds at times. Another
seasonably cool night with lows in the low/mid 60s most areas. Light
winds are expected after sunset. A few patches of fog are possible
mostly for the southern NJ/Delmarva areas.

For Wednesday, the surface high pressure will have moved offshore by
morning while the upper ridge continues across the Middle Atlantic
region. We expect another fine weather day with seasonable
temperatures and comfortable air. Low level moisture will begin to
increase as our region comes under the return flow behind the
departing high. High temperatures will reach the low/mid 80s most
areas with 70s at the shore and at the highest elevations N/W. Winds
will be Southeast to South and increase to around 10-12 mph during
the afternoon.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
High pressure will continue to move offshore Wednesday night into
Independence Day as a surface low and associated upper level trough
move eastward through eastern Canada. This will push a warm front
through the region early in the day Thursday allowing the area to
get into the warm sector. The warm front could bring a few isolated
showers or storms later Wednesday night into Thursday morning,
mainly over NE PA into NW NJ, with the greater chances for showers
and storms arriving later in the day Thursday. Prior to this, the
other story for the day will be the return of the heat and humidity
as highs for most areas will reach the upper 80s / low 90s (cooler
near the coast and over the Poconos) with dew points reaching the
upper 60s to low 70s. This will result in max heat indicies well
into the 90s to near 100 for most areas. As for the storm threat
later in the day, expect storms to fire in the vicinity of a
weakening frontal boundary draped over PA by the afternoon hours
with these storms moving eastward into our eastern PA and
northern NJ zones by later in the afternoon and then potentially
affecting Delmarva and southern and coastal NJ by the evening.
So it won`t be an all day type rain event but unfortunately the
timing won`t be great as it could interfere with Independence
Day festivities. Our POPs generally range from around 50 to 60
percent over eastern PA to 40 to 50 percent near the coast. With
ML CAPE values progged to max out around 1000-1500 j/kg along
with deep layer shear values around 30 knots there is the
potential some storms could become severe and it`s worth noting
the SPC has SE PA, Delmarva, and parts of southern NJ in a
MARGINAL risk for severe weather for Thursday. With PWATs
progged to reach 2.25+ inches, storms will also be capable of
producing very heavy rain which could lead to localized
flooding.

Storms may linger into a good portion of the evening Thursday before
diminishing overnight. It will be a very warm and muggy night as the
frontal boundary gets hung up over the area. Most areas won`t see
lows getting below the low/mid 70s (except 60s over the Pocono).

The front will remain draped over the area Friday as it extends to a
new low developing over the midwestern States that will lift
northward towards the Great Lakes. This will result in another hot,
humid day with chances for afternoon and early evening storms once
again. Storms should be a little less widespread though compared to
Thursday and this is reflected in our POPs which are more in the 20
to 30 percent range.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Low pressure lifts northward into Ontario Friday night into Saturday
with a strengthening southerly flow developing in the warm sector
over the area ahead of an approaching cold front. This will ratchet
up the mugginess even further with dew points potentially reaching
over 75 by Saturday afternoon. Combined with forecast highs for
Saturday once again in the upper 80s to low 90s for most areas, this
could bring peak heat indices in the range of 102 to 107
meaning heat headlines would be needed if this forecast holds.
The synoptic scale lift provided by the cold front along with
abundant moisture looks to result in widespread showers and
storms by Saturday afternoon into the evening. And at this
point, both severe weather and flash flooding look to be a
threat. Am particularly concerned seeing progged PWAT values by
both deterministic models and ensembles in the range of 2.25 to
2.5 inches which is close to climatological maxes.

Looking beyond Saturday into early next week, the cold front will
move through into Sunday but also tend to stall and "wash out" as it
moves across. Thus, while Sunday into early next week should be a
little more comfortable compared to Saturday in terms of heat and
humidity, it will still be quite warm and humid. Each day will also
see continuing chances for scattered showers/storms, mainly during
the afternoon and early evening hours, with POPs generally around 30
percent.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

.Tonight... VFR expected. Mostly clear skies expected. Light S/SE
winds, locally calm. High confid.

.Wednesday... VFR expected. Ci clouds with some diurnal Cu too.
Light S winds becoming SW around 10 knots by afternoon. High confid.

Outlook...

Wednesday night...VFR with no significant weather.

Thursday through Sunday...Sub-VFR conditions possible with chances
(30-60%) for SHRA and TSRA, especially in the afternoon and evenings
each day. The best chances for more widespread showers and storms
looks to be Saturday at this point.

&&

.MARINE...
Sub-SCA with fair weather tonight and Wednesday. Onshore winds
this afternoon and evening around 10 knots. Light winds tonight.
South or Southeast winds increasing to 10 to 15 kts by Wed
afternoon.

Outlook...

Wednesday night through Sunday...Conditions are forecast to be
below Small Craft Advisory criteria through the period though
southerly winds may gust to around 20 knots at times. There will
also be daily chances for showers and storms through the
period...especially in the late afternoon and evening periods.

Rip Currents...

Today...Northeast winds around 10 mph, becoming easterly in the
afternoon. Breaking waves around 1-2 feet. This yields a LOW
risk of the development of dangerous rip currents for both the
Jersey Shore and Delaware Beaches.

Wednesday...Southeast winds around 5-10 mph. Breaking waves
remain around 1-2 feet. Despite more of an onshore flow, with
light conditions expected, have continued with a LOW risk of
dangerous rip currents for both the Jersey Shore and Delaware
Beaches.

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

&&

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

&&

$$

SYNOPSIS...AKL/Fitzsimmons/RCM/Staarmann
NEAR TERM...OHara
SHORT TERM...Fitzsimmons
LONG TERM...Fitzsimmons
AVIATION...Fitzsimmons/OHara
MARINE...Fitzsimmons/OHara