629
FXUS61 KPHI 182321
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
721 PM EDT Thu Jul 18 2024

.SYNOPSIS...
High pressure will prevail through Friday across the region
with a frontal boundary stalling out south of the area. A weak
system passes by Saturday night, then high pressure will remain
offshore through much of next week with daily chances for
showers and thunderstorms.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 7:15pm...Minor changes to the forecast have been made to
reflect current conditions and observations. A rogue shower
developed over far southern Delaware, albeit is weakening and
should dissipate in the next hour.

The cold front remains situated offshore Delaware while continuing
to slowly slide southeastward. This will give way to a dry and
seasonably cool night with lows in the upper 50s to mid 60s N&W
and mid 60s to around 70 S&E.

Likely the nicest day of the week Friday with seasonable
temperatures, lower humidity, and mostly sunny skies as high
pressure continues to build in from the north and west. High
temperatures will be in the mid to upper 80s (right around the
climatological normal for mid/late July) with dew points mixing
out in the afternoon and dropping to the mid 50s to low 60s!

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
The stalled frontal boundary will begin to return northward on
Saturday as a shortwave trough nears the region. The trough and
associated jet streak will pass through overnight Saturday
night, then zonal flow returns by Sunday.

The main story for the weekend will be the return of more
seasonable humidity levels, though not oppressive with dewpoints
rising back up into the mid to upper 60s. Temperatures will
remain seasonable with highs in the mid to upper 80s and lows
mainly in the 60s. Friday night will likely be the coolest for
the foreseeable future with high pressure located overhead. Some
lows in the mid to upper 50s will be prevalent near/north of
I-78. The passing trough will yield an increasing chance for
convection by late Saturday into Saturday night. The question is
how much instability will be around during the overnight period
though since diurnally driven instability will be waning, so we
have advertised mainly 20-40% PoPs for now. Saturday should
also be fairly cloudy with the approaching system, but more sun
can be expected by Sunday. Some lingering convection possible
Sunday across the coastal plain with the boundary remaining in
the vicinity and diurnal instability developing. Severe
thunderstorms are unlikely during this period, but gusty winds
and heavy downpours may be possible.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The flow remains quasi-zonal into next week with a trough
approaching and upper jet streak increasing by Wednesday and
Thursday. At the surface, Bermuda high pressure remains offshore
and the frontal boundary will lift well north of the area. This
will translate to increasing chances for convection with each
day as synoptic support increases with each passing day.
Generally expect isolated to scattered showers and thunderstorms
each day, favoring the typical diurnally driven hours. Some
severe thunderstorms are possible, though the daily details on
the convective evolution remain unclear. Temperatures will
remain seasonable with highs ranging from the mid 80s to near 90
degrees and lows in the mid 60s to low 70s. Humidity will
increase slightly into next week with dewpoints returning to the
upper 60s to low 70s.

&&

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

Tonight...VFR. Northwest winds around 3-5 knots in the evening
veering to north/northeast while increasing overnight around
5-8 knots. High confidence.

Friday...VFR. North-northeast winds around 5 knots or less turn
more westerly in the afternoon. A seabreeze in the afternoon may
cause SE-S winds at KMIV/KACY late. High confidence.

Outlook...

Friday night through Sunday...Generally prevailing VFR. A
20-40% chance of showers or thunderstorms mainly Saturday night.
Patchy fog possible at night.

Monday and Tuesday...Generally prevailing VFR expected.
Scattered showers and thunderstorms likely each afternoon and
evening.

&&

.MARINE...
Winds and seas remain below SCA criteria through Friday. Winds
generally from the SSE around 10 kts or less veer to the N
overnight, becoming NNE around 10-15 kts Friday afternoon. Seas
around 3-4 feet.

Outlook...

Friday night through Tuesday...No marine headlines expected.
Scattered showers and thunderstorms possible Saturday night
through Tuesday, otherwise fair weather.

Rip Currents...

For Friday, winds will become northeasterly but remain around
10 mph. Wave heights will mainly remain around 1-2 feet in
Delaware and 2-3 feet in New Jersey with a 7-8 second period.
Therefore, the risk for the development of dangerous and life
threatening rip currents is forecast to be LOW at the DE beaches
and MODERATE at the NJ shore on Friday.

For Saturday, winds will become southeasterly at 5 to 10 mph.
Wave heights will drop to around 1-2 feet across all coastal
areas with a 6-7 second period. Therefore, the risk for the
development of dangerous and life threatening rip currents is
forecast to be LOW at all coastal areas on Saturday.

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

&&

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

&&

$$

SYNOPSIS...Staarmann
NEAR TERM...DeSilva/MJL
SHORT TERM...Staarmann
LONG TERM...Staarmann
AVIATION...DeSilva/MJL/Staarmann
MARINE...MJL/Staarmann