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093
FXUS61 KPHI 082031
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
431 PM EDT Wed May 8 2024

.SYNOPSIS...
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A front will move south of the area this evening and stall near
southern Delaware and southern Maryland through Thursday,
before an area of low pressure moves along it later Thursday.
The front then remains to our south through Friday, before
another low pressure system moves near the area later Friday
into Friday night. Yet another weak low pressure system may move
near the area Sunday, before high pressure builds south of the
Mid-Atlantic region Sunday night into Monday. More unsettled
weather could impact our area Tuesday into Wednesday as a storm
system approaches the area.
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&&

.NEAR TERM /THROUGH THURSDAY/...
Breezy the rest of the afternoon with southwest to west winds
gusting 20-25 mph. Broad upper level pattern is more zonal
overhead and with an airmass in place is quite dry through the
column, kept afternoon POPs below 15 percent. That said, can`t
fully rule out a rogue gusty shower before sunset.

As we head into tonight, initial area of low pressure continues
moving east off the coast of New England and out to sea. This will
push a weak cold front offshore through the evening. Meanwhile by
the overnight period the next wave of low pressure will be
approaching as it moves eastward through the midwestern states and
this will start to push the front back to the north as a warm front.
Clouds will once again be on the increase by the late overnight and
it`s possible we could see some showers start to enter the region
towards dawn, however the trend has been slower with these arriving
later. Expect lows ranging from the 50s north to the low 60s south.

Forecast guidance continues to step back from the severe
weather potential for Thursday, though the situation remains in
a bit of a flux. A few things are working in favor for a
diminished severe potential:

1) Guidance continues to trend further south with the track of
our system, lending to a cooler, cloudier day

2) Convective-allowing models are suggesting an overnight MCS
across the southern Mid Atlantic will lift northward along a
warm front and arrive around or shortly after daybreak Thursday,
largely robbing our region of instability for much of the day.

Because so much of the aforementioned elements depend on the
evolution of severe weather occuring across the Tennessee River
Valley today, there remains a higher than usual level of
uncertainty within our forecast. At any rate, the warm front and
how far north it is able to travel will be the limiting reagent
for our weather tomorrow. North of the front will remain cloudy,
showery, and overall dreary with temperatures stuck in the mid
to upper 60s with an easterly flow. South of the front, warmer
temperatures in the 70s with diurnal heating will lend to more
instability developing through the day, resulting in a higher
severe weather risk. At this point in the forecast, the frontal
boundary is expected to stall out just south of the Delmarva
Peninsula, keeping much of the severe weather potential in our
forecast area suppressed. A few elevated storms cannot be ruled
out, especially across the Delmarva and southern NJ, but the
severe weather threat, if this forecast holds, is expected to be
lower than previously forecast.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
Unsettled weather will continue for the Thursday night through
Friday night time period as our area will be north of a frontal
boundary located to our south, with a trough extending northward to
our west. An area of low pressure is forecast to develop along this
trough and move along the frontal boundary to our south through
Friday night. There will be plenty of moisture and lift across the
area, so showers and isolated thunderstorms will be possible.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Unsettled weather continues still into the weekend with showers
possible later Saturday into Sunday. For the first half of Saturday,
our area will be in between one area of low pressure located
offshore, and a second moving our of the Great Lakes region. As the
low moves out of the Great Lakes region and approaches the Mid
Atlantic later Saturday into Sunday, the potential for showers will
increase across the area.

A brief period of dry weather is expected later Sunday and 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 into Wednesday as a
storm system approaches from the southwest.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas...

Rest of today...VFR with westerly winds 10 to 15 gusting 20 to
25 knots. High confidence.

Tonight...Mainly VFR with winds becoming light and variable.

Thursday...Shower/storms likely along with lowering cigs and
visbys down at least MVFR at times. Winds generally east around
10 knots.

Outlook...

Thursday night-Saturday night...Sub-VFR conditions possible through
the period with showers possible at times.

Sunday...Sub-VFR conditions with showers, improving to VFR later in
the day.

Sunday night-Monday...VFR conditions expected.
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&&

.MARINE...
Conditions will remain below Small Craft Advisory through
Thursday. It will be quiet on the waters tonight but then
expect more rounds of showers with some storms as well during
the day Thursday as the next low approaches. East winds increase
through the day to around 10-15 gusting to 20 knots by late
day. Seas should generally be 2-4 feet.

Outlook...

Thursday night-Monday...Sub-Small Craft Advisory conditions are
expected through the period, although winds may gust around 20
knots at times through the period, and seas may approach 4- 5
feet for a period on Friday.

&&

.TIDES/COASTAL FLOODING...
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The new moon occurred Tuesday, May 7th, and this is resulting
in high astronomical tides. An offshore wind today is lowering
the surge some and some places may fall just short of advisory
criteria for minor flooding tonight. Opted to keep the advisory
as is given that several sites are forecast to reach minor
flooding tonight and early Thursday morning. As a front settles
to our south tonight, an onshore flow will develop and strengthen
some through the end of the week. 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.
There is some guidance that shows moderate flooding at some
coastal sites, however opted to keep it as minor given the
uncertainty. The Coastal Flood Advisory for minor tidal flooding
remains in effect for the Atlantic coastal zones, the Delaware
Bay, and the tidal Delaware River with the high tide cycle
tonight and early Thursday morning. Additional minor coastal
flooding is forecast with the evening/overnight high tides
through the end of the week.

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

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from 1 AM to 6 AM EDT Thursday for
     PAZ070-071-106.
NJ...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
     Thursday for NJZ016.
     Coastal Flood Advisory from 8 PM this evening to 2 AM EDT
     Thursday for NJZ012>014-020>027.
     Coastal Flood Advisory from 1 AM to 6 AM EDT Thursday for
     NJZ017>019.
DE...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
     Thursday for DEZ001.
     Coastal Flood Advisory from 8 PM this evening to 2 AM EDT
     Thursday for DEZ002>004.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Robertson
NEAR TERM...MJL
SHORT TERM...Robertson
LONG TERM...Robertson
AVIATION...MJL/Robertson
MARINE...MJL/Robertson
TIDES/COASTAL FLOODING...AKL/Gorse