773
FXUS61 KPHI 091901
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
301 PM EDT Thu May 9 2024

.SYNOPSIS...
Weak high pressure will remain across the northern Middle Atlantic
region into the evening. After that, several waves of low pressure
affect our area with the unsettled patterned continuing from later
tonight through Sunday. High pressure builds south of the Mid-Atlantic
region Sunday night into Monday. More unsettled weather may impact
our area next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
Weak high pressure was across the area much of the morning and for
the start of the afternoon. Low pressure well to the west is moving
rather quickly along the front (to our south) and will bring
poorer conditions for the evening and overnight. Showers have
already developed across southern NJ and northern Delmarva but
most of this activity is rather light and is diminishing. More
rains will develop and move across the region this evening and
then become steadier overnight. Low pressure will move offshore
by Friday morning and a NE flow around the N side of the low
will bring low clouds and rains to the region late tonight.

For Friday, the low will continue to move offshore, but an upper
trough and lingering low level moisture will keep plenty of clouds
and rains across the area Friday.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Unsettled weather will continue through Sunday with a brief
reprieve during the day on Saturday. PoPs remain in the 35-45 percent
range Friday night as the low continues to move offshore but by
early Saturday, the low looks to be far enough away that conditions
should be mostly dry regionwide. Lows Friday night will be mainly
in the mid-upper 40s and highs Saturday will warm back into the
low 60s.

By later in the day Saturday though, the next wave of low pressure
will arrive out of the Great Lakes, increasing chances for showers,
particularly northwest of the I-95 urban corridor. Showers continue
to move into the region Saturday night (PoPs 45-55 percent) with
lows again in the mid-upper 40s. Chances for rain will linger into
Sunday as well with highs once again in the low 60s.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A brief period of dry weather is expected beginning Sunday night and
continuing into Monday as high pressure briefly builds to the south
of the Mid Atlantic region. This dry weather will only be brief as
chances will begin to increase Tuesday night into Wednesday as a
storm system approaches from the southwest.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

into the evening... Mostly VFR with scattered showers. A brief
period of lower CIG/VSBY possible. Light variable winds probably
favoring NE or E most spots. Medium/high confid.

Tonight...Rain/showers becoming heavier and steadier with some
patchy fog likely as well. Cigs lowering to MVFR through the
evening with IFR cigs likely overnight. East winds around 10
knots. Moderate confidence.

Friday...Rain/showers continuing with conditions remaining IFR
likely through at least the first half of the day with some
improvement to low MVFR possible by afternoon. East to northeast
winds around 10 knots with some gusts to 15-20 knots. Moderate
confidence.

Outlook...

Friday night-Sunday...Sub-VFR conditions probable (50-60
percent chance) at times through the period with chances (40-50
percent) for showers.

Sunday night-Tuesday...VFR conditions expected through Monday. Sub-
VFR conditions with chances for showers return late Tuesday.


&&

.MARINE...

No significant changes in the thinking with regards to the marine
forecast. sub-SCA winds and seas continue thru the evening as
showers increase over the waters. SCA flags go up overnight from N
to S across our waters as winds/gusts slowly build. We have extended
the timing of the SCA flags further into Friday as seas will be
slower to diminish. Rain and fog late tonight and into Friday.
Thunder possible for the waters off Delaware.

Outlook...

Friday night and Saturday...Small Craft Advisory in effect for
Atlantic Ocean coastal waters through Saturday morning. Seas of 5-6
feet expected with winds gusting 20-25 knots. Sub-SCA conditions on
the Delaware Bay. Sub-SCA conditions return later in the day
Saturday.

Sunday through Tuesday...Overall, mainly sub-SCA conditions expected
through Monday. Stronger winds may bring SCA conditions back late
Monday into Tuesday.

&&

.TIDES/COASTAL FLOODING...
The new moon occurred Tuesday, May 7th, and this is resulting
in high astronomical tides. As a front settles to our south, an
onshore flow will develop and strengthen some through the end
of the week, peaking Friday into Friday night. While the
astronomical tides will be gradually lowering as we get farther
away from the new moon, the onshore flow should boost the surge
at least some. With this combination, widespread minor tidal
flooding is again expected with the high tide tonight into
early Friday morning for the Atlantic coastal zones, the
Delaware Bay, and the tidal Delaware River. As a result, another
round of Coastal Flood Advisories have been issued for these
areas.

With the peak onshore flow leading up to the Friday night high
tide cycle, guidance continues to show moderate tidal flooding
for portions of the coastal areas in the southern half of the
region with this high tide cycle. The most likely locations to
see moderate coastal flooding will be along the coasts in
Atlantic, Cape May, and Cumberland counties in New Jersey, and
Kent and Sussex counties in Delaware. Given that there is still
some uncertainty, opted to go with a Coastal Flood Watch for
these areas and further examination will be needed to determine
if these areas will need to be upgraded to a warning or to an
advisory for Friday night.

The Friday night high tide cycle looks to be the peak of the
coastal flooding potential but additional minor coastal flooding
is forecast with the evening/overnight high tide Saturday night
into early Sunday.

Flooding is not expected at this time for our Maryland zones
along the Chesapeake.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from 1 AM to 6 AM EDT Friday for PAZ070-
     071-106.
NJ...Coastal Flood Advisory from 11 PM this evening to 3 AM EDT
     Friday for NJZ016.
     Coastal Flood Advisory from 8 PM this evening to 2 AM EDT
     Friday for NJZ012>014-020>027.
     Coastal Flood Watch from Friday evening through late Friday
     night for NJZ021>025.
     Coastal Flood Advisory from 1 AM to 6 AM EDT Friday for
     NJZ017>019.
DE...Coastal Flood Advisory from 11 PM this evening to 3 AM EDT
     Friday for DEZ001.
     Coastal Flood Advisory from 8 PM this evening to 2 AM EDT
     Friday for DEZ002>004.
     Coastal Flood Watch from Friday evening through late Friday
     night for DEZ002>004.
MD...None.
MARINE...Small Craft Advisory from 2 AM Friday to 2 PM EDT Saturday for
     ANZ450-451.
     Small Craft Advisory from 6 AM Friday to 2 PM EDT Saturday for
     ANZ452-453.
     Small Craft Advisory from 11 AM Friday to 2 PM EDT Saturday
     for ANZ454-455.

&&

$$

SYNOPSIS...AKL/OHara
NEAR TERM...OHara
SHORT TERM...MJL
LONG TERM...MJL
AVIATION...Fitzsimmons/MJL/OHara
MARINE...MJL/OHara
TIDES/COASTAL FLOODING...