Cheltenham, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

261
FXUS61 KPHI 130559
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
159 AM EDT Wed Aug 13 2025

.SYNOPSIS...
High pressure will continue to be centered to our east through
Wednesday. A surface trough across our area Wednesday gives way
to a cold front crossing our area from the northwest during
Thursday. The front then settles just to our south into Friday
before dissipating by Saturday. High pressure arrives for
Saturday into Sunday, then a cold front crosses our area late
Sunday into Monday. High pressure starts to build in from the
north on Tuesday.

&&

.NEAR TERM /THROUGH TODAY/...
Surface high pressure remains located over the western Atlantic
through Wednesday.

Heading into tonight, skies will be mostly clear early with an
increase in clouds expected overnight. With light southerly flow
persisting, we`ll continue to see low-level moisture increase
as well. Hence, there likely will be another round of some low
stratus developing by early Wednesday morning with areas of
localized fog, perhaps dense at times, possible. Lows will be
mild ranging from the upper 60s to mid 70s.

For Wednesday, the prolonged stretch of dry weather will come
to an end as a shortwave approaches from the west during the
afternoon. As it does so, will begin to see an increase in
cloudiness along with the development of showers and
thunderstorms. With an abundance of moisture in place with dew
points in the low to mid 70s and PWATs in the 2.0-2.3" range,
any given shower or storm will be capable of producing very
efficient rain rates. While the severe weather threat is low,
our entire area is outlooked in a MARGINAL risk for excessive
rainfall by WPC. High temperatures are expected to range from
the mid 80s to low 90s areawide. No heat headlines are warranted
though as maximum heat indicies are only expected to top out in
the mid to upper 90s.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
A surface trough will shift eastward across the area Wednesday
night with lingering showers/thunder associated with it,
although the coverage is less certain. Any showers and
thunderstorms should be weakening as the night wears on as the
boundary layer stabilizes due to nocturnal cooling. It will be
warm and muggy however through Wednesday night. A weak cold
front is then forecast to settle southeastward across our area
during Thursday. While the forcing and focus for convective
development looks to be weak, a very warm/hot and humid air mass
will be in place ahead of the front. Some guidance has
increased the shower chances, targeting our northern areas more
during the day Thursday before some drier air starts to settle
southward. With the assumption of some more cloud cover across
the area and at least some convection around, high temperatures
are forecast to be near 90 degrees for most of the area. Dew
points in the low to mid 70s ahead of the front should start to
gradually decrease from the north through Thursday night as the
cold front is pushed southward.

As we go through Friday, the flow aloft becomes more zonal with
some lingering ridging initially across parts of eastern
Canada. This will support surface high pressure sliding by to
our north. This should assist in pushing the weak cold front
just to our south before it starts to dissipate. We have more of
the influence of the surface high to our north, however there
is no significant push of cooler air. The dew points are
forecast to come down some with enough drier air mixing in
especially during the daytime hours. While not much of a
focusing mechanism looks to be present to initiate convection, a
few showers cannot be ruled out in the afternoon as the air
mass will still be rather warm and humid enough. High
temperatures outside of the coastal areas and higher elevations
are forecast to be in the upper 80s to 90 degrees. The dew
points look to be in the 60s to low 70s (highest across the
southern areas), therefore still on the humid side.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Summary...Warm/hot with lingering humid conditions, then the
start of some cooling Tuesday. The chances for showers and
thunderstorms range from low to none.

Synoptic Overview...Our region will remain on the north part of
an east to west ridge to start the weekend. An upper-level
trough moving across eastern Canada over the weekend and early
next week should result in the ridge retreating south and
westward. At the surface, a cold front is forecast to cross our
area late Sunday into Monday followed by high pressure from the
north on Tuesday.

For Saturday and Sunday...Our region is forecast to be on the
northern part of a strong west to east mid/upper level ridge to
start the weekend. An upper-level trough moving across eastern
Canada though looks to push the ridge south and westward with
time. This will result in the heights lowering some across the
Northeast into the northern Mid-Atlantic, however given the
stronger part of through is well to our north our temperatures
should not be impacted much. As a result, the warm to hot
conditions are forecast to continue with daytime highs reaching
the 80s to low 90s. While the dew points may come down some, it
still looks to be on the humid side. Heat indices are still
forecast to be below heat advisory criteria, with these values
the highest on Sunday. A cold front associated with the upper-
level trough arrives late Sunday. Other than an isolated shower
or thunderstorm possible mainly well inland and across the
higher elevations each afternoon, the probability of convection
currently is looking to be very low.

For Monday and Tuesday...The aforementioned upper-level trough,
most pronounced well to our north, is forecast to push a cold
front to our south. Given that the stronger dynamics are
currently forecast to be passing by well to our north, the
forcing and low-level convergence looks to be much weaker across
our area. Surface high pressure then starts to build into our
area from the north on Tuesday. Some cooling is forecast to
start taking place on Tuesday, and at least some lowering of the
dew points should occur although to what extent will depend on
the southerly push of the incoming air mass change. Given
increased uncertainty with the details/timing, made no changes
from the NBM which also includes 20-30 percent chances for
showers and thunderstorms across our area.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Early this morning...Conditions lower to at least MVFR/IFR in
most spots, but possibly as low as LIFR at KMIV/KACY. Nearly
calm winds. Low confidence in just how low conditions will get.

Today...Conditions improve to VFR by 14Z to 15Z. Late day
SHRA/TSRA will result in brief sub-VFR conditions. S to SW winds
5 to 10 kt. Moderate confidence overall.

Tonight...Lingering SHRA/TSRA will taper off in the evening,
though may persist at KMIV/KACY for most of the night.
Conditions lower to MVFR/IFR in fog/stratus once again late
tonight. LGT/VRB winds.

Outlook...

Thursday...Times of sub-VFR conditions mostly due to any
showers or thunderstorms.

Friday through Sunday...VFR overall.

&&

.MARINE...
No marine headlines are in effect through Wednesday. Southerly winds
around 10-15 kt are expected with occasional gusts up to 20 kt
possible. Seas of 2-3 feet. Fair weather expected through tonight,
with a chance of showers and thunderstorms on Wednesday.

Outlook...

Wednesday night through Sunday, the conditions are anticipated to be
below Small Craft Advisory criteria.

Rip Currents...

For Wednesday, winds will generally be out of the south at
10-15 mph with higher gusts at times. Wave heights will be 2-3
feet with an easterly swell of 2 feet. The period will be
around 8 seconds. All of these factors have resulted in a
MODERATE risk for rip currents for the Jersey Shore and a LOW
risk for the Delaware Beaches.

For Thursday, winds will be more out of the southwest at 5-10
mph with a wave height of 1-2 feet. The period will be 7-9
seconds. Due to these factors, a LOW risk of rip currents is in
place for all of the Jersey Shore and Delaware Beaches.

&&

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

&&

$$

SYNOPSIS...Gorse
NEAR TERM...DeSilva/Fitzsimmons
SHORT TERM...Gorse
LONG TERM...Gorse
AVIATION...DeSilva/Fitzsimmons/Gorse/MPS
MARINE...DeSilva/Gorse/Guzzo