233
FXUS61 KPHI 090724
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
324 AM EDT Wed Jul 9 2025

.SYNOPSIS...
A slow moving frontal boundary will waffle across the Mid-
Atlantic through late week as additional disturbances move
through. Bermuda high pressure will be in place through the
weekend, eventually breaking down for the start of the new work
week. Several disturbances will pass through over the weekend as
well.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weak, diffuse frontal boundary continues to sit over the mid
Atlantic but the storms from earlier have ended. In it`s wake it
will continue to be a warm, muggy overnight period with chances for
a few lingering showers, mainly near and south of the urban
corridor. Also expect some patchy fog and low stratus around.

Wednesday will virtually be a rinse and repeat kind of day in terms
of the overall forecast, except the frontal boundary will have made
its way closer to the area, suppressing the overall threat of
convection a bit further south. Expecting partly cloudy skies in the
morning to give way to mostly cloudy skies come the afternoon. With
the tropical and deep moisture airmass persisting in addition to the
nearby frontal boundary, yet another round of showers and
thunderstorms will develop around late afternoon on Wednesday.
Greatest threat will be from Philadelphia on south, where better
atmospheric parameters overlap with one another, so SPC has a SLIGHT
risk in those areas, with a MARGINAL risk remaining elsewhere.
Similarly, WPC has kept a SLIGHT risk for excessive rainfall for
most of the area on Wednesday as little change in the overall
atmospheric environment is expected. A new Flood Watch for flash
flooding is in effect that basically includes all areas from the I-
78 corridor southward. Compared to Tuesday, the timing of the
convection will be a bit later...mainly after 5 PM so we begin the
Flood Watch at this time. All in all another muggy and humid day is
expected. Temperatures will be a few degrees cooler due to more
cloud cover compared to today where heat indicies will largely
remain in the 90s for the majority of the area. So it looks like
we`ll fall short of needing any heat headlines.

Showers and storms continue Wednesday evening with the severe threat
gradually diminishing with time but the flash flood threat
persisting at least through the evening period. PWATs will remain
around 2 inches meaning heavy downpours will be capable of producing
locally 2-3 inches of rain within a 1 to 3 hour timeframe.
Showers/storms are likely to linger overnight near and south of the
urban corridor however the intensity of them and associated rainfall
rates should diminish. The Flood Watch runs until 2 AM. Lows by
Thursday morning should be mainly in the upper 60s to low 70s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
A warm and humid airmass will be over the Northeast and Mid-
Atlantic for the Short Term period. Surface dew points will be in
the low to mid 70s, along with highs generally in the mid 80s. This
will yield heat index values in the low to mid 90s. These high dew
points will also keep low temperatures at night quite warm, and lows
will generally be in the lower 70s.

Unsettled weather will remain on tap as a frontal boundary will
hover over the area. Abundant low level moisture will be in place
given those high dew points, and PWATs will be up to and in excess
of 2 inches.

Another round of showers and thunderstorms will impact the area
Thursday afternoon and evening as shortwave energy approaches from
the west and passes through the region. Given how warm and humid
conditions will be, locally heavy rain and damaging wind gusts are
possible once again. This pattern will repeat yet again on Friday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A fairly typical summertime pattern is on tap for the Long Term
period with warm and very humid conditions. Surface dew points will
generally be in the low to mid 70s though it is possible that during
the peak heating of the day dew points drop by a few degrees due to
mixing. Highs will generally be in the mid to upper 80s, possibly
around 90 in some spots. This will give way to max heat index values
generally in the low to mid 90s.

A series of disturbances will pass through the region from time to
time, but confidence in timing and placement is low. Will generally
follow the NBM and go with 30 to 50 percent PoPs for most of this
time, though the NBM is indicating 60 percent PoPs for the southern
Poconos, Lehigh Valley, and Berks county on Sunday due to a stronger
system possibly approaching then. Important to note that any showers
and thunderstorms will mostly be in the afternoon and evening hours
and there are not many factors indicating precipitation would be
widespread and organized at this time.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Rest of overnight...There will continue to be some fluctuation
in conditions with low MVFR to IFR cigs at times due to low
stratus...mainly for RDG, ABE, TTN, and PNE. Some patchy fog
will continue to be around as well and could affect TAF sites.
Southwest winds around 3-6 kt. Low confidence.

Wednesday...Primarily VFR with another round of showers and
thunderstorms developing by late afternoon. Any showers and
storms may cause localized areas of VSBY/CIG restrictions.
Southwest winds around 5-10 kt. Moderate confidence.

Wednesday night...Showers and storms continuing with associated
restrictions to at least MVFR at at times. Winds light and
variable (around 5 knots or less) but generally favoring a S to
SW direction.

Outlook...

Thursday through Sunday...Overall, VFR conditions. However,
afternoon and evening SHRA/TSRA may result in brief sub-VFR
conditions if a given storm passes over a terminal. Sub- VFR
conditions possible at night due to fog and low clouds, but
confidence low on timing and placement.

&&

.MARINE...
No marine headlines are in effect through Wednesday night. Some
showers are lingering early this morning over our southern
waters with another round of showers/storms expected late
Wednesday into Wednesday night. These could once again bring
localized wind gusts in excess of 34 kt.


Outlook...

Thursday through Sunday...Sub-SCA conditions for this period.
Afternoon and evening showers and thunderstorms possible each
day. VSBY restrictions possible from time to time, especially at
night.

Rip Currents...

For Wednesday, a south/southwest shore parallel wind of around
10-20 MPH and breaking waves of around 2-3 feet will result in
a MODERATE risk for the Jersey Shore. With wind direction mainly
offshore along the Delaware Beaches, a LOW Risk for rip
currents is in place. Similar conditions are expected for
Thursday so we`ll continue with a MODERATE risk for the Jersey
shore and a LOW risk of rip currents for the Delaware Beaches.

Rip currents occur often in the vicinities of jetties and piers
and the speed of the currents are generally maximized at low
tides.

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

&&

.HYDROLOGY...
A Flood Watch was issued for areas along and south of I-78 for
Wednesday. Rainfall of around 0.5 inches to upwards of 3 to 4
inches fell across the watch area. This results in a saturated
surface and low FFG values within the watch area. It will not
take much to cause further flooding issues, especially in SE PA,
where widespread flooding was reported today. Rainfall rates of
2 to 3 inches per hour are possible with thunderstorms rolling
through Wednesday Evening.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch from this afternoon through late tonight for
     PAZ060>062-070-071-101>106.
NJ...Flood Watch from this afternoon through late tonight for
     NJZ009-010-012>027.
DE...Flood Watch from this afternoon through late tonight for
     DEZ001>004.
MD...Flood Watch from this afternoon through late tonight for
     MDZ012-015-019-020.
MARINE...None.

&&

$$

SYNOPSIS...Fitzsimmons/MPS
NEAR TERM...DeSilva/Fitzsimmons/Hoeflich/Staarmann
SHORT TERM...Fitzsimmons/MPS
LONG TERM...Fitzsimmons/MPS
AVIATION...DeSilva/Fitzsimmons/MPS
MARINE...DeSilva/Fitzsimmons/MPS
HYDROLOGY...