078
FXUS61 KPHI 022019
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
419 PM EDT Tue Sep 2 2025

.SYNOPSIS...
High pressure will gradually weaken as it shifts to our east
through Wednesday. A cold front crosses our area into Friday,
followed by another cold front later Saturday. High pressure
then builds in during Sunday and Monday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
We presently are stuck on the southeast side of a surface ridge
axis and an upper level low pressure. This has resulted in our
relatively cool but dry weather of late. The upper low will lift
northward through tomorrow, while the surface ridge will shift
southeastward, so overall, we should see a slightly more sunny
and warmer Wednesday versus what we`re seeing today, as winds
shift southerly and heights build aloft. Before that happens,
however, the ongoing easterly flow may combine with a weak
shortwave moving in this evening to spark off a stray shower or
sprinkle, so have included it for our evening forecast, mainly
west of Philly. Otherwise, expect a partly cloudy night. As
winds become light and variable while the ridge axis moves
overhead, some patchy fog could develop, with the best (albeit
weak) signal being across central NJ, but right now this doesn`t
look widespread. Lows tonight will be in the 50s generally, with
highs on Wednesday creeping a bit closer to 80 thanks to the
aforementioned southerly flow and slightly diminished cloud
cover.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Overview: An upper-level low that is closed off in Canada will
remain steady in its placement through the short term period and
then meander off to the northeast by the beginning of the long term
period. There will be two pieces of upper-level vorticity that
rotates around this closed low and at the surface they will be
in the form of cold fronts.

Wednesday night will be dry and mostly clear. Temperatures will fall
into the 50s across the area. A southerly wind on Thursday ahead of
our first cold front will allow temperatures to climb into the mid
70s to mid 80s. What we will also notice is the humidity creeping up
with dew points starting to get into the 60s. In terms of the
actual cold front, it continues to be trending later and weaker.
Some isolated showers develop in the afternoon and early
evening. The bulk of the precip does not arrive until late
evening and overnight with scattered showers at times and even
an isolated thunderstorm. The better potential for these showers
and a possibility of an isolated thunderstorm is for areas west
of I-95. As you head east, it trends drier as the front
continues to weaken as it heads east.

We are drying out by Friday morning, a stray shower is still
possible throughout the day from some troughing behind the cold
front but it appears limited in coverage. We also do not cool off
behind the cold front. Temperatures will be in the mid 70s to
upper 80s on Friday with dew points well into the 60s. It stays
warm Friday night with lows in the low 60s to low 70s and dew
points in the 60s. Otherwise, Friday night is dry and mostly
clear.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Overview: Main weather feature in the long term is a cold front
on Saturday with a surface high pressure system then building in for
the end of the weekend and into early next week.

A second cold front moves through late Saturday into Saturday night.
This looks to be a stronger cold front than the one on Thursday
night as the dynamics and upper-level support looks better. Showers
start to develop in the afternoon and early evening. Coverage
picks up throughout the evening and into the early overnight.
Some isolated thunderstorms are also possible. This will not be
a widespread rain event but the coverage across the area looks
better with this cold front compared to the one on Thursday.
Ahead of this cold front, temperatures get into the upper 70s to
upper 80s with dew points well into the 60s to near 70.

Behind the cold front, we notice a change as cooler air filters in.
By Sunday, highs are in the upper 60s to upper 70s with dew points
in the 40s and 50s. A lingering shower is still possible on Sunday
but most stay completely dry. We then stay in a similar air mass
into the beginning of next week. Conditions also look to stay pretty
dry overall into the beginning of next week with a broad surface
high pressure system building in.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Thru 0Z...Prevailing VFR conditions. Isolated shower/sprinkle
possible but unlikely to affect flight category. Winds out of
the southeast 10 KT or less. High confidence.

Tonight...Mostly VFR, though spotty sub-VFR cigs/vsby possible
overnight, with highest (albeit not much) confidence around
KTTN. Isolated shower/sprinkle possible but unlikely to affect
flight category. Winds are east to southeast during the evening,
then light and variable most places overnight. Moderate
confidence.

Wednesday...Prevailing VFR after any low cigs/vsby dissipate.
Winds shifting southerly 5-10 kts. Moderate confidence.

Outlook...

Wednesday night...Prevailing VFR. A slight chance (20%) for
lower ceilings.

Thursday...MVFR visibility or ceiling restrictions will be possible
with showers and thunderstorms primarily in the afternoon and
evening hours.

Friday...VFR. No significant weather expected.

Saturday...Sub VFR conditions possible. Showers and
thunderstorms may result in temporary visibility and ceiling
restrictions in the afternoon and evening.

Sunday...VFR. No significant weather expected.

&&

.MARINE...
Winds and seas are expected to be below Small Craft Advisory
Criteria thru Wednesday.

Outlook...

Thursday through Saturday...Southerly winds increase ahead of a cold
front Thursday and remain in place into Saturday evening. Wind gusts
could approach 25 knots and seas may reach 5 feet for a time.

Sunday...Sub SCA conditions are expected.

Rip Currents...

Wednesday...Northeasterly wind 10 mph will become east-
southeasterly in the afternoon. Breaking wave heights 2 to 3
feet, with a 7-8 second period. Given the forecast trend of
wind being more onshore, have opted for a MODERATE risk for the
development of dangerous rip currents at all beaches. Some
guidance is depicting a higher risk, but at this point, it seems
like tomorrow will be very similar in terms of surf conditions
to today, so have opted to keep it moderate. However, will be
watching closely to monitor for any changes.

Thursday...Winds become more southerly and increase to 10-15 mph
by the afternoon. The period continues to be around 7-8 seconds
but rapidly decreases to 4-5 seconds by the late afternoon.
Breaking wave heights are forecasted to be 2-3 feet. Given
these forecast conditions a MODERATE risk for the development
of dangerous rip currents at all beaches is expected.

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

&&

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

&&

$$

SYNOPSIS...Johnson/RCM
NEAR TERM...RCM
SHORT TERM...Guzzo
LONG TERM...Guzzo
AVIATION...Guzzo/RCM
MARINE...Guzzo/RCM