391
FXUS61 KPHI 281046
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
646 AM EDT Sat Jun 28 2025

.SYNOPSIS...
A warm front to our south and west will gradually lift northward
today. It will be followed by a weak cold front stalling nearby
early Sunday. The front then shifts northward as a warm front
Monday followed by a cold front later Tuesday. High pressure
builds closer later Wednesday into Thursday before settling over
our area on Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
A warm front will move northward across the area slowly today.
The low clouds and scattered showers will continue until the
front passes later this morning and into the afternoon.
Following the front skies will become partly/mostly sunny from S
to N across the area. This will cause temps to jump into the 80s
for many areas today. The warmth and humidity will contribute to
more scattered showers/tstms for the mid/late afternoon and into
the evening. The SPC has indicated that a Marginal risk for
severe weather will be around the area today. Damaging winds
with any tstm are possible. Highs will be mostly mid/upper 80s
for S/E areas and low 80s N/W. Rain chances haven`t changed
much since yesterday with likely pops N/W and chance pops for
the Delaware Valley and S/E.


Tonight the weak cold front will cross the area and it will
continue to trigger some scattered showers/tstms as it passes.
There is still a potential for some gusty damaging winds with
any thunderstorm this evening as the front passes. As the night
continues, the instability will diminish and coverage and
intensity of any convection will be reduced as well. Patchy fog
will develop in areas that receive rains today. Lows will not be
that cool with the weak cold air advection behind the front.
Temperatures will only fall into the low/mid 70s for
Philadelphia, south NJ and Delmarva. Up across the NW counties,
the lows will be in the low/mid 60s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A more zonal flow aloft from the Midwest to the Northeast is
forecast to be in place Saturday night into Sunday. A shortwave
trough embedded in this flow looks to slide by to our north into
Saturday evening. Surface low pressure tied to this feature
tracks well to our north, however a weak cold front associated
with it arrives into our area Saturday evening. This front
should tend to stall in our vicinity Sunday as the flow remains
mainly zonal aloft. Some showers and thunderstorms should
accompany the front into Saturday evening, a few which could
produce locally damaging wind gusts. Some drier air will also
start to arrive from the west in the wake of the front later
Saturday night, although much of the area will remain on the
muggy side Saturday night.

Some additional drying is forecast to take place on Sunday with
dew points dropping into the 60s for much of the area, although
a more humid feel may linger across parts of Delmarva. The
extent of the drying will depend on where the surface front sets
up. There does not appear to be a real strong focus for
convective development during Sunday, although a few showers or
thunderstorms cannot be ruled out mainly across Delmarva where
deeper moisture may remain longer. High temperatures are
forecast to be well into the 80s for the majority of our area,
and with lower dew points the heat indices are forecast to be
lower Sunday afternoon compared to Saturday afternoon.

As we go through Monday, an upper-level trough across the
Midwest and adjacent Canada is forecast to shift eastward and
amplify some as it approaches the Northeast. A front warm lifts
north across our area on Monday. A few showers or thunderstorms
are possible with the northward movement of the warm front, with
the greatest chance (40- 50 percent) mainly across southwestern
parts of our forecast area. Temperatures will make a run at 90
degrees for many areas and with dew points on the rise, heat
indices will also be on the increase. As of now, the forecast
heat indices are below Heat Advisory criteria (even for the the
I-95 urban corridor, Wilmington to Philadelphia to Trenton,
where the criteria is lower through June 30th).

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Summary...Some showers and thunderstorms to start, otherwise no
extreme heat forecast.

Synoptic Overview...An upper-level trough is forecast to move
into much of the East by later Tuesday. This trough looks to
become reinforced as it remains across much of the East through
the end of next week. At the surface, a cold front moves through
later Tuesday, then high pressure builds closer later Wednesday
into Thursday before settling over our area on Friday.

For Tuesday...An upper-level trough is forecast to shift
eastward and amplify some as it overspreads the Northeast and
Mid-Atlantic. This will drive a cold front across our region
later Tuesday. An uptick in the shear is forecast, especially
across Pennsylvania and New Jersey where the stronger mid level
flow is forecast to be. Moderate instability may develop and if
this overlaps with the greater shear, a favorable area for
severe thunderstorms (damaging winds) may develop Tuesday
afternoon and/or early evening. The details will depend on the
magnitude of the shear and instability as well as the timing of
the cold front and upper-level trough axis. Temperatures are
forecast to top out between 85-90F for much of the region,
although if cloud cover and convection hold off long enough the
highs could be a little higher than forecast. While it will be
rather humid, extreme heat is currently not forecast.

For Wednesday and Thursday...The upper-level trough across the
Northeast and Mid-Atlantic may tend to sharpen again as
additional energy rounds its base. The cold front should be
south and east of our area to start Wednesday, and while
temperatures do not look to drop much, the dew points are
forecast to lower some in the wake of the cold front. Despite
the presence of the upper-level trough, less in the way of
deeper moisture should keep the instability lower as well. Given
surface high pressure building closer to our area with time,
the chance for any showers and thunderstorms at this time is
little to none.

For Friday...The upper-level trough is forecast to still be in
place with weak surface high pressure becoming more established
over our area. The return flow up the Ohio Valley will increase
the low-level warm air advection with a northeastward moving
warm front. The forcing for this, as of now, looks to remain
well to our west and therefore little in the way of shower
chances. Daytime temperatures in the 80s for most, and the dew
points are forecast to be in the low to mid 60s.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

.Today... Low CIGS and some reduced VSBYs too (especially KACY/KMIV)
will continue into the morning as a slow moving front crosses the
area. While improving conditions are expected today, the exact time
of the categories is somewhat uncertain, I have generally kept the
TAFS (at 06Z) similar to the previous ones since the guidance seems
to support the slow improvement trends. Scattered showers thru the
day and a few tstms during the afternoon. Low/medium confid overall.

.Tonight... Scattered showers and tstms this evening will bring
localized lower CIGS/VSBYs with low-end MVFR or IFR possible. After
that, winds will shift to West/Northwest and improving conditions
overnight. VFR is possible by dawn Sunday at KPHL and nearby sites
too. Medium confid overall.


Outlook...

Sunday...VFR overall.

Monday...A few showers and thunderstorms, with lower ceilings
and visibilities at times, are possible.

Tuesday...Showers and some thunderstorms probable with local
restrictions, especially in the afternoon and evening.

Wednesday...VFR overall.

&&

.MARINE...
Winds will veer from SE early this morning to SW by late afternoon
and into the evening. After that, winds will further switch to West
Sat night. Winds and seas will remain below SCA conditions as a warm
front crosses the waters today and tonight. Seas on the ocean will
be mostly around 3 to 4 ft while 1 to 2 ft waves will be across
Delaware Bay. We`ll continue with the Dense Fog Advisory for the
waters this morning and mention scattered showers/tstms for today
and tonight.

Outlook...

Sunday through Wednesday...The conditions are anticipated to be
below Small Craft Advisory criteria. A few gusty thunderstorms
possible mainly Saturday night and again Tuesday afternoon/evening.

Rip Currents...

For today, the flow turns southerly so there will be less of an
onshore component however the seas will continue to be around 3
to 4 feet with a lingering onshore swell. For this reason,
we`ll continue with a MODERATE risk for the development of
dangerous rip currents for the NJ Shore and Delaware Beaches.

For Sunday, seas lessen some and winds become more variable,
however the period will increase to around 9 seconds with
breaking waves around 2 to 3 feet. Thus, we`ll keep a MODERATE
risk for the development of dangerous rip currents for the NJ
Shore and Delaware Beaches.

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

&&

.TIDES/COASTAL FLOODING...
With onshore flow decreasing today, no further widespread tidal
flooding is expected. Only spotty minor tidal flooding will be
possible with tonight`s high tide along the Delaware Bay and
tidal Delaware River.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Heat Advisory from noon today to 8 PM EDT this evening for
     PAZ070-071-102-104-106.
     Coastal Flood Advisory until 7 AM EDT this morning for PAZ070-
     071-106.
NJ...Heat Advisory from noon today to 8 PM EDT this evening for
     NJZ015-017>019.
     Coastal Flood Advisory until 7 AM EDT this morning for
     NJZ017>019.
DE...Heat Advisory from noon today to 8 PM EDT this evening for
     DEZ001.
MD...None.
MARINE...Dense Fog Advisory until noon EDT today for ANZ431-451>455.

&&

$$

SYNOPSIS...Gorse
NEAR TERM...OHara
SHORT TERM...Gorse
LONG TERM...Gorse
AVIATION...Gorse/OHara
MARINE...AKL/Gorse/OHara
TIDES/COASTAL FLOODING...AKL