029
FXUS61 KPHI 131749
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
149 PM EDT Sat Jul 13 2024

.SYNOPSIS...
Several weak waves of low pressure will ride along a stationary
front draped over our region today. High pressure returns late
tonight and persists through Tuesday night. A cold front
approaches from the northwest on Wednesday before crossing our
area during Wednesday night. High pressure then builds back in
from the west to end the week.

&&

.NEAR TERM /THROUGH SUNDAY/...
Diurnally driven showers and storms are possible through
evening. Favored area for development is along the front, but
could see some development in the higher terrain of the Poconos.

Tonight, high pressure builds in from the west. Abundant low
level moisture will remain in place, and It looks like we will
have a similar set up to last week when we had several days in a
row for marine fog encroaching on the coast. Not confident yet
on how far inland dense fog will get, so no dense fog advisories
at this time, but will be watching trends closely.

For tomorrow, zonal flow aloft and very light flow in the low
levels. With moisture still in place, we`ll have another chance
for isolated or scattered showers. Think the coverage will be
limited as we will lack a focus for surface convergence.
Additionally, some model soundings are depicting a mid level
inversion which would limit instability.

As for the heat, no significant changes at this time with the
temperatures and heat index values. Although by strictest heat
index criteria, we are forecasting to barely get to heat
advisory criteria, this is the start of a multi-day excessive
heat risk, combined with relatively warm lows tomorrow morning
means little in the way of relief.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
Have extended the heat advisory through Sunday, and the
excessive heat watch has been expanded to include more of NJ and
Delmarva. The watch also now includes Tuesday and Wednesday.

Rather benign conditions continue into Sunday night under mostly
clear skies. Lows may be a degree or two warmer compared to
Saturday night as southerly flow is a bit stronger than the
night before.

High heat and humidity will continue to impact the area through
Wednesday before a cold front crosses through the area on
Wednesday night.

Afternoon highs are forecast to be in the mid to upper 90s on Monday
and Tuesday, when the highest temperatures are likely to occur. Dew
points are also expected to further increase into the low to mid 70s
which will result in heat indicies upwards of 105-110 degrees across
most interior locations. Due to this potential, have opted to issue
an Excessive Heat Watch for Monday and Tuesday with this update
for the same areas where Heat Advisories are in effect for
Sunday. A chance of diurnally driven thunderstorms are possible
each afternoon as well.


&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...

On Wednesday, the heat and humidity will continue as a cold
front approaches. This should result in a more widespread chance
for showers and storms late in afternoon into the evening
hours. Depending on the progression of the front, shower
activity may linger into Thursday as well. However, with the
front working its way through the region, temperatures by late
week are expected to be a few degrees below normal.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today.... Conditions should continue to improve to VFR across
the region. Some sites are already VFR, but expect everywhere to
return to VFR by 18Z. There is a chance for some afternoon
SHRA/TSRA, but that threat/coverage is minimal and confidence
is too low to warrant mentioning in the TAF. Light S winds,
becoming 5 to 10 kt this afternoon. Moderate confidence overall.

Tonight...VFR initially. Fog is likely to develop after 06Z,
resulting in MVFR or even IFR visibility restrictions. LGT/VRB
winds. Moderate confidence.

Outlook...

Sunday through Tuesday night...VFR. Otherwise, a slight chance
of a shower or thunderstorm each afternoon.

Wednesday...Primarily VFR but sub-VFR conditions possible. A chance
for showers and thunderstorms in the afternoon.

&&

.MARINE...
Sub-Small Craft Advisory conditions for today and tonight for S
winds 10 to 15 kt with occasional gusts up to 20 kt.

VSBY restrictions in showers and fog. Visibility restrictions
in fog likely tonight, and may be reduced to under 1 NM late
tonight as well.

Outlook...

Saturday night through Tuesday night...No marine headlines expected.
Wind gusts generally between 10-20 kt and seas around 2-4 feet.

Wednesday...SCA conditions possible due to winds around 20 kt and
seas build to around 4-5 feet.

Rip Currents...

For Saturday, southerly winds around 10-20 MPH with an onshore
component in Cape May, Atlantic, and Ocean County will result in
a MODERATE risk for rip currents. This is aided by breaking
waves of 2 to 4 feet. Flow will be more shore parallel in
Monmouth County and the Delaware Beaches with a LOW risk for rip
currents.

For Sunday, weak flow out of the south remains, though with
decreasing wave heights and a 5 to 7 second period, a LOW risk
for rip currents is in place at all coastal locales.

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

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Heat Advisory from 10 AM Sunday to 6 AM EDT Tuesday for
     PAZ060>062-070-071-101>106.
     Excessive Heat Watch from Tuesday morning through Wednesday
     evening for PAZ060>062-070-071-101>106.
NJ...Heat Advisory from 10 AM Sunday to 6 AM EDT Tuesday for NJZ009-
     010-012-013-015>022-027.
     Excessive Heat Watch from Tuesday morning through Wednesday
     evening for NJZ007>010-012-013-015>022-027.
DE...Heat Advisory from 10 AM Sunday to 6 AM EDT Tuesday for DEZ001.
     Excessive Heat Watch from Tuesday morning through Wednesday
     evening for DEZ001.
     Excessive Heat Watch from Tuesday morning through Wednesday
     evening for DEZ002>004.
MD...Excessive Heat Watch from Tuesday morning through Wednesday
     evening for MDZ012-015-019-020.
MARINE...None.

&&

$$

SYNOPSIS...DeSilva/Wunderlin
NEAR TERM...Johnson
SHORT TERM...DeSilva/Johnson
LONG TERM...DeSilva/Wunderlin
AVIATION...DeSilva/Johnson/MPS
MARINE...DeSilva/Gorse/Hoeflich/Johnson/MPS/Staarmann