Upper Merion, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

170
FXUS61 KPHI 022312
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
712 PM EDT Wed Jul 2 2025

.SYNOPSIS...
A stalled cold front across the area today will begin to move
south on Thursday, and then move offshore Thursday night. Dry
high pressure will build into the region on Friday and remain in
control through much of the weekend, providing seasonable
temperatures and tranquil weather conditions. Warmer, more
humid, and unsettled conditions will return early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
The last of the showers have moved out with skies slowly
clearing from west to east. Things continue to quiet down into
tonight as the front slowly moves offshore and an area of high
pressure nudges in from the southwest. Mostly clear skies are
expected overnight with temperatures dropping into the 60s.
Cannot rule out some fog developing after midnight.

Quiet through the morning tomorrow before things turn a bit
more active in the afternoon. Another cold front is expected to
dive in from the northwest, triggering the development of some
showers and thunderstorms. Forcing will be strongest north of
Philadelphia as the upper level trough slides by and we should
destabilize quite nicely with mostly sunny skies to start the
day. CAMs show around 1000-1500 J/KG of MLCAPE for the northern
half of the region with 35- 45 kt of 0-6km shear. 12z CAMs have
certainly trended a bit more robust with tomorrow`s convection,
forming a line of thunderstorms to our northwest, and having it
push through during the mid to late afternoon and into the
evening. SPC has added a SLGT (2/5) risk for severe weather for
tomorrow from Philadelphia on north, which lines up with the
strongest forcing, highest instability, and strongest shear. The
main threat will be damaging wind gusts. As thunderstorms
progress through the CWA, they should weaken especially after
sunset with the loss of daytime heating. Temperatures climb into
the mid to upper 80s though a few spots could touch 90.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
A trough axis will shift southeastward across northern portions
of the area Thursday night. At the surface, a cold front will
move off of the coast, taking any shower and storm chances with
it.

Behind the cold front, temperatures will cool into the mid 60s
across most locations Thursday night, with mid-upper 50s likely
in portions of the Poconos.

High pressure will build into New England and portions of the
Mid- Atlantic Friday and Saturday. This is expected to bring
tranquil weather conditions. Partly to mostly clear skies can be
expected through the period, with afternoon highs in the low
80s across the Poconos and mid 80s elsewhere, and overnight lows
in the upper 50s to lower 60s. It looks like Independence Day
will have great weather overall!

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Mid-level ridging and surface high pressure should remain in
control across the area on Sunday. A general continuation of the
benign pattern is expected, with a mixture of clouds and sun.
Afternoon highs on Sunday are expected to be in the mid-upper
80s, with lows Sunday night ranging from the mid 60s to near 70.


Monday and beyond, ridging will begin to settle over
southwestern and south central portions of the US, allowing for
a slight southward progression of the polar jet. It currently
appears that a weak shortwave will pass through the region on
Monday. A weak frontal passage should accompany this feature,
and isolated to scattered showers and storms will be possible.
An isolated severe threat cannot be entirely ruled out given the
anticipated strong instability. Monday looks to be the warmest
day of the extended period, with highs in the upper 80s and
lower 90s, and lows in the upper 60s to lower 70s.

Additional rounds of isolated to scattered, mostly diurnally
driven convection, will be possible Tuesday and Wednesday with a
few weak disturbances passing through. Temperatures may be
modulated a bit by increased cloud cover and storm coverage,
with afternoon highs generally in the mid 80s and lows in the
mid 60s to lower 70s.

&&

.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...Mainly VFR with a few mainly high clouds at times.
Could be a bit of patchy mist or light fog in southern NJ
terminals. Light winds favoring a westerly component around 5
kt or less. High confidence.

Thursday...Primarily VFR. Scattered showers and thunderstorms
possible after 18z, esp at KRDG/KABE/KTTN, though only around a
30-50% chance. Westerly winds around 5-10 kt with a few gusts to
20 kts. A few storms could produce much stronger winds. Moderate
confidence.

Thursday night...Primarily VFR. Scattered showers and
thunderstorms possible before 3z, but only a 20-40% chance.
Winds turning northwesterly 5-10 kts. A few storms could
produce much stronger winds. Moderate confidence.

Outlook...

Friday through Sunday night...VFR. No significant weather
expected.


Monday...Mainly VFR. Brief reductions to sub-VFR are possible
in isolated to scattered showers and storms, primarily in the
afternoon and evening hours.

&&

.MARINE...
Sub-SCA conditions expected through tomorrow. West/southwest
winds 5- 10 kt and seas 2 to 3 feet.

Outlook...

Thursday night through Monday...Sub-SCA conditions are
anticipated. Winds are expected to remain below 25 kt and seas
below 5 ft through the period.

Rip Currents...

For Thursday, Southwest winds around 10 mph with breaking wave
heights of 1-3 feet. The residual SSE swell will lower to 1-2
feet and shorten to 6-8 seconds. As a result, have maintained a
LOW risk for dangerous rip currents for all beaches.

For Friday, northwest wind in the morning will become
southeasterly during the afternoon at 5-10 mph, with breaking
wave heights of 1-3 feet. Southeasterly swell around 2 feet at
7-8 seconds in length. Will carry a MODERATE risk for dangerous
rip currents for all New Jersey beaches outside of Monmouth
county, where the wind will be more shore-parallel. Will carry a
LOW risk for dangerous rip currents for Monmouth County 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...Cooper/DeSilva/Staarmann
NEAR TERM...Hoeflich
SHORT TERM...Cooper
LONG TERM...Cooper
AVIATION...Cooper/Hoeflich/RCM
MARINE...Cooper/Hoeflich