Clayton, Delaware 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

750
FXUS61 KPHI 110138
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
938 PM EDT Mon Mar 10 2025

.SYNOPSIS...
High pressure will be over the area through Tuesday, and then a
cold front passes through the region Tuesday night. High
pressure settles over eastern Canada Wednesday through Friday. A
warm front lifts north on Friday night, and high pressure
establishes itself over the Mid-Atlantic this weekend until a
strong cold front passes through the region late Sunday. High
pressure returns on Monday.

&&

.NEAR TERM /THROUGH TUESDAY/...
Not much change in the overall weather pattern is expected
through Tuesday as flow aloft is zonal and the area remains
wedged between low pressure systems. Clear skies are expected
through Tuesday. Fly in the ointment could be on the onshore
flow which developed along the coast today, which may bring
enough humidity to cause a little patchy fog overnight. Winds
will be light and variable tonight with low temperatures in the
mid to upper 30s to around 40 degrees.

Tuesday will essentially be a rinse and repeat of Monday, though
slightly warmer inland and a little cooler along the coast. The
biggest difference is south- southwesterly flow will be a bit
stronger as the other low tracks through the northern Great
Lakes. Expecting winds between 10-20 mph during the afternoon
especially across northern and western areas. In short, Tuesday
has the `classic` spring-like set-up where temps will vastly
over-perform compared to any model guidance. With this in mind
and slightly better mixing expected, have forecast highs mainly
in the upper 60s to low 70s across interior locations and mid
50s/low 60s across the higher terrain and along the coast. There
also will be an increased risk for fire spread (more details
can be found in the Fire Weather section below).

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Low pressure passing north of the area will drag a cold front
through the region Tuesday night. Since all of the upper level
support will be well north of the area, not expecting any
precipitation with its passage. A cooler airmass spreads into
the region for Wednesday with highs some 10 degrees cooler
compared to Tuesday.

High pressure then builds into eastern Canada Wednesday night
and Thursday, with the base of the high down by New Jersey. A
weak cold front passes through the region Wednesday night, and
this may tough off some light rain showers, with some light snow
showers in the southern Poconos. Not much, if any QPF and/or
snowfall is expected. This will set up onshore flow that, given
ocean temperatures in the low to mid 40s, should result in highs
in the 50s for most areas, though inland areas should get into
the 60s. One thing to monitor is that projected dew points look
to be in the mid 40s or so, and if these dew points are at or
above ocean temperatures, there could be fog issues, especially
along the coasts.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
High pressure remains over eastern Canada through Friday before
departing Friday night. Another dry and relatively warm day on
tap with conditions similar to Thursday.

A warm front lifts north through the region Friday night, and
then strong southerly flow sets up, allowing for warm air
advection and highs in the 60s and low 70s this weekend. Strong
low pressure lifting north of the region will drag a cold front
east on Sunday. A secondary low forms on this front as an upper
trough digs in behind the front. Breezy conditions set up on
Sunday with southerly winds 15 to 20 mph with 25 to 35 mph
gusts. Showers develop Sunday afternoon and evening with the
passage of the cold front. Some strong to potentially severe
thunderstorms are possible as well, but it is too soon to say as
the mesoscale factors needed for severe weather have yet to
show themselves. Will include a chance for thunderstorms Sunday
afternoon and evening.

Turning much cooler and drier behind the cold front on Monday
with highs generally in the 50s.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Overnight...VFR/SKC. Light south winds around 5 kt or less,
becoming calm at times. Small chance of some patchy fog at KACY
due to marine influence. High confidence overall, lower
confidence on any patchy fog near KACY.

Tuesday...VFR/SKC. South-southwest winds around 7-12 kt with
gusts up to 15-20 kt in the afternoon. High confidence.

Outlook...

Tuesday night through Wednesday...VFR.

Wednesday night through Thursday night...VFR on Thursday, but
potential for sub-VFR conditions at night in fog and/or low
stratus.

Friday through Saturday...VFR.

&&

.MARINE...
No marine headlines are in effect through Tuesday. South-
southwest winds around 10-15 kt becoming light and variable
overnight. Light winds will continue through Tuesday morning
before settling out of the south around 10-15 kt on Tuesday
afternoon. Seas of 1-2 feet tonight and 2-3 feet on Tuesday.
Fair weather.

Outlook...

Tuesday night...Sub-SCA conditions.

Wednesday through Wednesday night...Mostly sub-SCA conditions,
but seas may build close to 5 ft on the ocean waters on
Wednesday.

Thursday through Friday...Sub-SCA conditions.

Saturday...SCA conditions likely.

&&

.FIRE WEATHER...
On Tuesday, winds will be slightly stronger compared to Monday,
as south-southwest winds will be around 10-15 mph southeast of
the I-95 corridor and 15-25 mph northwest of the I-95 corridor.
MinRH values will be in the 25-35% range. Due to the higher wind
potential across eastern Pennsylvania and northern New Jersey,
there may be an increased risk for fire spread. Will discuss
with our fire weather partners and neighboring forecast offices
accordingly in order to determine if a Special Weather Statement
is warranted.

&&

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

&&

$$

SYNOPSIS...MPS/RCM
NEAR TERM...DeSilva/RCM
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...DeSilva/MPS/RCM
MARINE...DeSilva/MPS/RCM
FIRE WEATHER...