452
FXUS61 KPHI 090827
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
427 AM EDT Thu May 9 2024

.SYNOPSIS...
Several waves of low pressure affect the region with the
unsettled patterned continuing from today through Sunday. High
pressure builds south of the Mid-Atlantic region Sunday night
into Monday. More unsettled weather could impact our area
Tuesday night into Wednesday as a storm system approaches the
area.

&&

.NEAR TERM /THROUGH FRIDAY/...
350 AM...A complex weather pattern continues to unfold across
the eastern U.S. early this morning. An initial area of low
pressure is moving out to sea east of New England with its
trailing cold front having pushed into southern Delmarva. This
front then extends back to the west to the next area of low
pressure over Illinois. Showers and thunderstorms are ongoing
near and ahead of this next low and are affecting areas to our
south and west into the Carolinas and Virginia.

As we go into the day today, low pressure tracks east to
east-southeastward toward Virginia with some showers starting
to move into the area by around the late morning to early
afternoon time frame and then continuing off and on for the
remainder of the day. These showers will be associated with the
remnants of the convection currently ongoing to our south and
west. Given that the forecast track of the low has shifted
southward, this will limit the threat of severe weather over our
area as the front will remain hung up near Delmarva. It`s still
possible a few stronger storms could affect Delmarva this
afternoon into this evening but even here it looks like any
instability will be mainly elevated tending to limit the threat.
Farther north over eastern PA into adjacent portion of NJ,
there may not even be any thunder due to lack of instability.
The clouds and showers will keep it much cooler today with east
to northeast winds north of the front. Generally expect highs in
the upper 60s to low 70s with low to mid 60s right near the
coast and over the southern Poconos.

As we go into tonight, rain/showers should actually become more
widespread and steadier as the upper level trough that`s been
driving this unsettled weather shifts eastward towards the coast
increasing PVA over the mid Atlantic. This will result in the
surface low tending to get hung up just south and east of DE
helping keep the rain/showers going. There could be some
embedded thunder but mainly over Delmarva. The precipitation
may also be moderate to occasionally heavy although we don`t
expect there to be much in the way of hydro concerns. Overnight
lows range from mid 40s north to low/mid 50s south.

Friday is definitely shaping up to be quite unsettled and cool
with periods of rain continuing as the upper level trough will
be very slow to translate eastward through the area. This will
keep a surface trough over the mid Atlantic even as the center
of low pressure starts to track out to sea. Brisk winds out of
the east/northeast will add to the rawness of the day with most
areas seeing highs only in the low to mid 50s and the southern
Poconos likely not getting out of the 40s.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Unsettled weather will continue for the Friday night through the
Saturday night time frame though a brief respite from the shower
chances will occur during the early part of 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.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Unsettled weather continues to end the weekend with showers
possible into Sunday. The low tracking across the region will
begin to push offshore early Sunday but showers may continue to
linger for much of the day.

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 night into Wednesday as a storm system approaches from
the southwest.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Rest of overnight...VFR with winds becoming north and then
northeasterly at around 4 to 8 knots. High confidence.

Today..Mostly cloudy with cigs lowering with time and some
showers moving in by afternoon. It should remain mostly VFR
through around 20z before MVFR cigs start to develop. Winds
generally east to northeast around 5 to 10 knots. Moderate
confidence.

Tonight...Rain/showers becoming heavier and steadier with some
patchy fog likely as well. Cigs continuing to lower with IFR
likely by the overnight period. 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-Monday...VFR conditions expected.

&&

.MARINE...
Conditions will remain below Small Craft Advisory levels
through today though expect some showers moving in over the
waters by this afternoon.

Rain/showers become more widespread over the waters tonight
with winds and seas starting to ramp up from north to south. A
Small Craft Advisory begins overnight for our northern ocean
zones with these conditions spreading into our southern ocean
zones off the coast of southern NJ and DE Friday morning. The
conditions should remain sub SCA over the Delaware Bay.

Outlook...

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

Saturday through Monday...Overall, mainly sub-SCA conditions
expected through the period though seas may linger around 5 feet
during the day on Saturday.

&&

.TIDES/COASTAL FLOODING...
The new moon occurred Tuesday, May 7th, and this is resulting
in high astronomical tides. High tide has passed at most
locations and water levels have receded below advisory
thresholds outside of a few locations along the tidal Delaware
River. As a front settles to our south early this morning, 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 tidal Delaware River with the high tide cycle
early this 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 until 6 AM EDT early this morning for
     PAZ070-071-106.
NJ...Coastal Flood Advisory until 6 AM EDT early this morning for
 NJZ017>019.
DE...None.
MD...None.
MARINE...Small Craft Advisory from 2 AM Friday to 6 AM EDT Saturday
     for ANZ450-451.
  Small Craft Advisory from 6 AM Friday to 6 AM EDT Saturday
  for ANZ452-453.
  Small Craft Advisory from 11 AM Friday to 6 AM EDT Saturday
 for ANZ454-455.

&&

$$

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