213
FXUS61 KPHI 090155
AFDPHI

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

.SYNOPSIS...
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.

&&

.NEAR TERM /THROUGH THURSDAY/...
Front continues settling slowly southward across the region,
with cooler and, more notably, drier air setting in on
northwesterly winds. These winds will shift northerly and then
northeasterly overnight.

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
continues to be 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 our portion 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 are likely, especially north
and west of I-95. Temperatures will be quite cool, with low-mid
50s for highs on Friday for much of the area.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Unsettled weather continues still into the weekend with showers
possible late 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 /02Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Rest of Tonight...Mainly VFR with winds becoming north and then
northeasterly 5-10 kts.

Thursday...Showers likely by afernoon 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.

&&

.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...A period of Small Craft Advisory
conditions is possible as low pressure passes the region late
Thursday night into Friday, with easterly winds gusting 25-30
kts and seas building to around 5 ft. Sub-Small Craft Advisory
conditions are expected beyond Friday.

&&

.TIDES/COASTAL FLOODING...
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.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from 1 AM to 6 AM EDT Thursday for
     PAZ070-071-106.
NJ...Coastal Flood Advisory until 2 AM EDT Thursday for NJZ016.
     Coastal Flood Advisory until 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 until 2 AM EDT Thursday for DEZ001.
     Coastal Flood Advisory until 2 AM EDT Thursday for DEZ002>004.
MD...None.
MARINE...None.

&&

$$

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