Glendon, Pennsylvania Weather Forecast Discussion

811
FXUS61 KPHI 191834
AFDPHI
Area Forecast Discussion
National Weather Service Mount Holly NJ
234 PM EDT Fri Sep 19 2025
.SYNOPSIS...
A cold front which is crossing the area this afternoon will move
offshore this evening. A strong high pressure system then builds
in southeast across the Middle Atlantic beginning late tonight.
The high remain in place through the weekend before weakening
and shifting slowly eastward during the first half of next week.
After it moves away, moderating temperatures and a few chances
for rain are expected.
&&
.NEAR TERM /THROUGH SATURDAY/...
Latest surface analysis places weak high pressure over the
southern part of our region. At the same time, a cold front is
beginning to push southward through the region, with a stronger
high pressure following behind it in southern Canada. Aloft, a
broad trough is positioned across much of eastern Canada into
the northeastern United States, with a weak ridge to our west
across the western Great Lakes and Ohio Valley.
Through tonight, the ridge aloft will actually build eastward
toward our region even as the surface cold front presses
southward into our area. Thus, there is very little risk for any
precipitation or even a whole lot of clouds with this surface
front which is pretty lacking for any upper-level support.
Therefore, with northwesterly winds prevailing, expect the
remainder of the day to be mostly sunny and warm, though
humidity will diminish a bit. Highs generally in the 80s.
Tonight, northerly winds continue as the surface front settles
south and the high to the north builds in somewhat, while the
ridge aloft also builds in. Thus, a dry night is on tap. Lows
40s in the Poconos and NW NJ, 50s I-95 corridor away from the
urban core, and 60s Delmarva, urban core and immediate NJ
shore. Some cloud coverage may develop along the coast with the
front lingering to the south of the region and onshore flow
increasing.
Heading into Saturday, conditions remain largely the same as
high pressure continues to build in. Some clouds may continue to
linger along the coast but otherwise, mostly sunny skies are
expected. High temperatures will be mainly in the mid-upper 70s.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
A couple dry days for the short term. High pressure with some weak
upper ridging will remain across the Middle Atlantic region. The
previous (06Z) NAM was trying to back  coastal low, complete with
measurable QPF to the shore areas and ern Delmarva. The newer run
has flipped back to a more offshore solution. The GFS is trying to
bring a little QPF to Delmarva early Sunday, but not too confident
in this attm. We`ll continue with a dry fcst attm and mention extra
cloudiness for shore areas late Sat night and into Sunday.
Temperatures will be a bit cooler than normal Sunday, but then rise
to close to normal for Monday. Normal highs for late September are
in the mid/upper 70s S/E and upper 60s/low 70s N/W. Normal lows are
typically in the 50s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
High pressure that brought all the nice weather during the short
term will be exiting to the east Monday night, so we`ll still have
dry conditions for then. It will probably continue into Tuesday
morning too, before a more unsettled pattern arrives. Lows Monday
night will still be mild for late September with upper 50s/low 60s
regionwide.
This next system develops across the Midwest states and shortwave
energy causes low pressure to form/strengthen near Chicago. This low
is then carried by the upper trough across Ohio/New York then
offshore Long Island by Thursday. Since our region will be ahead of
this low we will see an increasing southerly flow of milder and more
humid air. This will result in scattered showers in the Tue thru Thu
period. Right now, pops are mostly in the chance range with 25%-40%
common, but higher pops are in the N/W most areas for Tue as the
best factors all align there. There could be scattered tstms as well
for later Tue and into Tue evening.
Temperatures for Tue/Wed will be above normal with Tue being the
milder of the two days. Highs Tue will be mostly upper 70s/low 80s
for the area. It`ll feel rather summer-like too with dew points
close to 70 degrees. Readings will be a few degrees cooler for
Wednesday with a continuation of the pattern. After t
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Rest of Today...VFR. Some fair weather afternoon cu with SCT
035-045 bases possible. Northwest winds 10 knots or less. High
confidence.
Tonight...VFR with northwest winds shifting northeast overnight,
but remaining 10 kts or less. Some scattered stratus may
develop along the coast late in the overnight hours as onshore
flow increases. High confidence.
Saturday...VFR. Winds becoming easterly around 10 knots. Higher
gusts up to 20 knots at KMIV/KACY. High confidence.
Outlook...
Saturday night through Sunday night...Restrictions are possible,
especially for NJ/Delmarva depending on the extent of potential
marine stratus.
Monday through Monday night...VFR. No significant weather.
Tuesday through Wednesday...Period of Sub-VFR conditions are
possible in isolated showers and storms, particularly during the
afternoon hours.
&&
.MARINE...
Fair weather will continue on the waters through Saturday. A
cold front will approach later today and while no significant
weather is expected with it, winds will switch to south as it
approaches. Seas will be around 2 ft today. 1 to 2 ft waves for
Delaware Bay. Winds shift northerly behind the front tonight,
and may gust near 25 kts in the morning on Saturday with seas
building to 3-4 ft, but confidence on SCA headlines is low at
this time.
Outlook...
Sat night/Sunday morning... Fair weather expected. Winds and seas
should remain below SCA levels.
Sunday afternoon thru Monday... Fair, but low-end SCA possible
with near 5 ft seas.
Monday night/Tue... Fair weather expected. Winds and seas should
remain below SCA levels.
Tue night thru Thursday... Low-end SCA conditions for seas possible.
Scattered showers. A few tstms possible Tue afternoon/evening.
Rip Currents...
Rest of today, We`ll continue with a LOW risk for the development
of dangerous rip currents at all beaches.
For Saturday, a surge in northeasterly winds are forecast to
develop from north to south, with speeds increasing to 15-20
mph. A southeast swell is forecast to be on the weaker side with
wave heights 1-2 feet with a period of 5-7 seconds. Building
waves in the surf zone (2-4 feet) should be much more dominant
over the swell. As a result, went with a MODERATE risk for the
development of dangerous rip currents at the Jersey Shore and
LOW at the Delaware Beaches. If the stronger wind surge and
higher breaking waves arrive faster at the Delaware Beaches, the
rip risk will then increase.
For specific beach forecasts, visit weather.gov/beach/phi
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.
&&
$$
SYNOPSIS...OHara/Guzzo/RCM
NEAR TERM...AKL/RCM
SHORT TERM...OHara
LONG TERM...OHara
AVIATION...AKL/OHara/Guzzo
MARINE...AKL/OHara

NWS PHI Office Area Forecast Discussion