Mc Adoo, Pennsylvania Weather Forecast Discussion

810
FXUS61 KPHI 281709
AFDPHI
Area Forecast Discussion
National Weather Service Mount Holly NJ
109 PM EDT Sun Sep 28 2025
.SYNOPSIS...
A weak low pressure system will continue to impact the area
overnight followed by high pressure building in through Sunday.
This high will maintain its influence over the area into the new
work week. Another cold front will pass through the area around
mid-week, followed by a strong high pressure system building
southward in its wake through the remainder of the week.
&&
.NEAR TERM /THROUGH MONDAY/...
We continue to see a clear sky with some sunshine for the
remainder of the day as a high pressure system is building in
from the north and west. This does start to change a bit as we
head through the evening and into tonight. Clouds for our
coastal areas and southeastern zones do start to filter back in.
Overnight, clouds look to be mainly confined south and east of
the I-95 corridor. It will be a clear sky as you head west and
mostly to partly cloudy as you head southeast. Due to a pretty
clear sky overall across the area, light winds, and even some
lingering moisture near the ground from previous rain will lead
to some potential patchy fog. Right now, the best confidence
looks to be Delmarva, parts of New Jersey, and parts of the
Lehigh Valley. Lows tonight are in the mid 50s to mid 60s.
On Monday, our high pressure system remains our dominant weather
feature. This high pressure system does retreat slightly to the
northwest which will allow moisture to usher in from the south in
the form of mid and high level clouds. Now there are ongoing
tropical systems in the Atlantic to our southeast, but with high
pressure being our main dominant weather feature, it will keep those
systems away from our area. What we mainly see is some of this
moisture moving into our area from the south in the form of the
cloud cover mentioned above. There may even be a spotty to
isolated light shower in Delmarva but that seems pretty limited
at this time. Highs on Monday are in the mid 70s to low 80s.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
High pressure just to our northwest will retreat slowly farther
to the northwest Monday into Monday night as two tropical
systems meander well to our southeast. At this point all
precipitation associated with these systems is expected to stay
to our south but there will be increasing cloud cover,
especially by Tuesday. However much of this cloud cover will be
of the mid and high level variety so we`ll still likely see at
least some filtered sunshine, especially Monday. Generally
expect highs in the 70s to around 80 with Tuesday being the
cooler of the two days due to more cloud cover. Lows Monday
night will range mainly from the mid 50s north to the mid 60s
south. A cold frontal passage late Tuesday into Tuesday night
will result in lows about 4-8 degrees cooler for Tuesday
night...mainly ranging from the upper 40s to low 50s north with
upper 50s to around 60 south. Northeast winds will also start to
ramp up Tuesday night, especially along the coast, due to an
increasing pressure gradient between the high to our northwest
and the tropical systems to our south. By the predawn hours of
Wednesday morning winds along the coast look to generally be 15
to 20 gusting up to 30 mph.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The combination of a strong cold front and lingering tropical
systems well off the coast will result in a continuing tight
pressure gradient through midweek. This will result in breezy to
windy conditions along the immediate coast, with a gusty breeze
reaching areas further inland as well, but not nearly as
strong. The cold front`s passage will also bring a much cooler
air mass to the region, likely the coolest so far this season,
with highs failing to reach 70 across the region by Thursday
despite fairly copious sunshine. The nights will also turn
chilly with 40s and 50s Wednesday night and even some high 30s
in the Poconos and NW NJ by Thursday night. Wouldn`t rule out
some frost by then, at least in the colder spots. As a strong
Canadian high builds southward and overhead late in the week
into early next weekend, winds relax and temps start to
moderate, with widespread low 70s likely for highs by Saturday,
and lows at least staying clear of the 30s by then. No
precipitation is expected through the period.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...
Rest of Today...VFR with winds N-NW around 5 kt or less.
High confidence.
Tonight...VFR initially, but VSBY restrictions in BR possible
(20 to 30 percent) after 06Z. Nearly calm winds. Low confidence
on sub-VFR conditions.
Monday...VFR with winds out of the NE at 5-10 knots.
Outlook...
Monday night through Thursday...VFR likely through the period.
&&
.MARINE...
Sub-Small Craft Advisory conditions through Monday. A south to
southeast wind today becomes west to northwest late tonight at
5-10 kts. By Monday the wind is northeast at 5-10 knots. Seas 2
to 4 feet.
Outlook...
Monday night through Thursday...Building waves and winds as
tropical systems well offshore bring fringe effects to our
waters. Waves likely exceed SCA levels starting Monday night,
peaking Wednesday then slowly diminishing starting Thursday.
Wave heights may exceed 10 feet for a few days. Winds will be
slower to ramp up but likely exceed SCA levels by Tuesday night
with gales possible later Tuesday night lasting into Thursday,
with the highest chance being Wednesday.
Rip Currents...
Today...Mainly northeasterly wind at 5-10 mph. Breaking wave
heights generally 1-2 feet. A southeasterly swell from offshore
storms starts to increase late in the afternoon. Initially, our
period is around 6 seconds but does start to increase later in
the afternoon with the potential for a longer period swell
developing at a period of around 10 seconds. Given these
factors, have opted to maintain a LOW risk for the development
of dangerous rip currents at all beaches at this time.
For Monday, the increasing influence of longer period swells
around 13 to 16 seconds combined with there being multiple swell
groups will result in a MODERATE risk for the development of
dangerous rip currents at all beaches. Generally expect wave
heights in the surf zone to be around 2-3 feet.
For specific beach forecasts, visit weather.gov/beach/phi
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.
&&
$$
SYNOPSIS...Fitzsimmons
NEAR TERM...Guzzo
SHORT TERM...Fitzsimmons
LONG TERM...Fitzsimmons
AVIATION...Fitzsimmons/Guzzo
MARINE...Fitzsimmons/Guzzo

NWS PHI Office Area Forecast Discussion