540
FXUS61 KAKQ 232303
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
703 PM EDT Mon Sep 23 2024

.SYNOPSIS...
High pressure builds south along the Mid-Atlantic coast early
this week. Meanwhile, a series of shortwave troughs will slide
across the region in northwest flow aloft bringing unsettled
conditions through midweek. Temperatures will be on the cool
side of seasonal averages Tuesday and gradually moderate through
midweek.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 330 PM EDT Monday...

Key Message:

- A chance for showers tonight, especially west of I-95.

- A chance for showers lingers into Tuesday morning.

GOES water vapor channels depict a building ridge over the Ohio
Valley with an upper low drifting SE well offshore. At the
surface, 1022mb high pressure is centered over Atlantic Canada
and continues to ridge to the SW along the Mid-Atlantic coast.
The backdoor cold front from yesterday has become rather
diffuse, but is still noted by stratus over western NC and NW
SC. Mostly cloudy this afternoon across the NW 2/3rds of the
area, and partly sunny SE. There are some light
showers/sprinkles from N and NW of the RIC metro to the Northern
Neck and MD Eastern Shore associated with some shortwave energy
sliding across the northern Mid-Atlantic. Temperatures are
primarily in the lower to mid 70s.

The upper ridge axis shifts toward the Mid-Atlantic coast
tonight into Tuesday with additional shortwave energy rounding
the northern periphery of the ridge. Showers potentially move
into the Piedmont this evening, then scattered showers develop
along and W of the I-95 corridor overnight into Tuesday morning.
PoPs diminish Tuesday afternoon as shortwave energy lifts NE of
the local area. QPF overnight into Tuesday is generally
0.1-0.25" but some locally higher amounts are possible. A few
rumbles of thunder are possible over the SW Piedmont with some
elevated instability. Mostly cloudy to overcast tonight into
Tuesday. Lows tonight are mainly in the lower to mid 60s.
Considerable cloud cover will keep highs in the upper 60s to
around 70F over the NW Piedmont Tuesday, with lower to mid 70s
elsewhere.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 330 PM EDT Monday...

Key Messages:

- Cloudy with multiple chances for showers, primarily west of
  I-95.

The upper ridge axis moves offshore Tuesday night into
Wednesday allowing deeper SW flow to develop over the Mid-
Atlantic, with a closed anticyclone developing offshore. This
should allow the residual boundary to lift N and the surface
high should nudge offshore. Additional shortwave energy will
bring a chc of showers and embedded tstms Tuesday night. Higher
rain rates are possible with this system given deeper moisture,
especially over the Piedmont. Current storm total QPF (including
tonight into Tuesday morning) is generally 0.4-0.6" W of the
I-95 corridor, but higher amounts are certainly possible. Lows
Tuesday night are mainly in the 60s. Warmer and more humid
Wednesday with highs ranging from the mid 70s NE to the lower
80s SE. The closed upper high eventually links with a ridge over
the Midwest Wednesday night into Thursday between the potential
tropical cyclone over the Gulf and a trough over the Saint
Lawrence Valley. This will result in diminished rain chances.
Lows Wednesday night will mainly be in the mid to upper 60s,
followed by highs Thursday in the upper 70s to lower 80s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 330 PM EDT Monday...

Key Message:

- Multiple low-end chances for rain late this week from the
potential development of a tropical system in the Gulf of Mexico.

Friday has the highest rain chances (especially to the SW of
the local area) around 40-50%. There is some uncertainty on
direct impacts as the rainfall will be correlated to the
current low pressure system building in the Caribbean Sea that
is likely to become a tropical system. There is decent model
agreement on the cutoff low over the midwest absorbing the
potentially tropical low pressure. This could keep the bulk of
the rainfall to the local area`s SW. It is still too early to
determine impacts to the local area at this time.

The majority of the area on Saturday and Sunday have a slight chc of
showers. Temperatures won`t feel like autumn yet with highs in the
upper 70s on Saturday and mid 70s on Sunday and Monday.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 200 PM EDT Monday...

VFR conditions will continue for the remainder of the day and early
overnight. Patches of fog will begin to develop towards the VA
piedmont region overnight. RIC will have MVFR to IFR conditions in
the early morning. As for the rest of the major terminals, VFR
conditions will remain. Winds tonight and in the morning are from
the E at 5-10kt.

Chc of showers increases overnight into Wednesday(especially
inland). MVFR and locally IFR flight restrictions are possible with
the chance of rain Tuesday and Wednesday. Thursday will be drier,
but chc of showers returns on Friday.&&

&&

.MARINE...
As of 330 PM EDT Monday...

Key Messages:

- Small Craft Advisories remain in effect for all coastal
  waters through Wed due to elevated seas.

- Persistent long period swells keep seas elevated through this
  week.

- Southeast to northeast winds may become elevated this
  weekend.

Low pressure continues to linger well off the East Coast, with
a strong high pressure over New Brunswick this afternoon. Winds
this afternoon were generally E/NE ~10 kt. E/ESE winds briefly
increase to 10-15 kt this evening across the Ches Bay and rivers
before diminishing overnight. Winds will be nearly the same as
today for Tue with a brief surge to ~15 kt with a few gusts up
to 20 kt possible in the late afternoon/evening. Winds then
remain generally SE 5-10 kt through Thu night before increasing
to 10-15 kt with gusts up to 20 kt Fri. Forecast uncertainty
increases Fri into the weekend as the winds will depend on how
Potential Tropical Cyclone Nine (PTC 9) interacts with a large
cutoff low moving into the MS Valley. The exact strength and
track of both the tropical system and the cutoff low will be key
to determining the local impacts to wind. For now, there still
appears to be a potential for SCA winds (15-20 kt) from either
SE winds Fri or ENE winds this weekend. However, confidence has
decreased. Winds on the 12z models aren`t as high due to high
pressure building in to the NE of the local area Fri, helping
the tropical system curve away from the local area (to the W)
and placing the better pressure gradient SW of the local waters.
Expect forecast changes in the coming days as details regarding
both the cutoff low and PTC 9 become more clear.

Waves and seas this afternoon were generally 1-2 ft (2-3 ft at
the mouth of the bay) and 4-6 ft (6-7 ft across the northern
coastal waters) respectively. Expect seas to remain elevated
through this weekend. As such, have extended SCAs (for seas)
through Wed (with future extensions likely). Additionally, there
will be a brief period where waves at the mouth of the bay may
reach 3-4 ft Tue evening with the brief surge. However,
confidence is too low to issue SCAs with this update.
&&

.TIDES/COASTAL FLOODING...
As of 700 PM EDT Monday...

Key Messages:

- Long duration coastal flood event continues across the region
  (see section below for info on this being a record at a few
  sites).

- Coastal Flood Warnings remain in effect from Windmill
  Pt/Tappahannock northeastward to the bay side of the MD
  Eastern Shore, with advisories elsewhere.

- At least minor flooding is likely to persist through Tuesday,
  possibly into Wednesday in portions of the mid/upper Bay.
  Various headlines remain in effect (see latest CFWAKQ for
  details).

Tidal departures continue to average +1.5 ft to +2.0 ft above
astro tide levels across the region. Solid moderate tidal
flooding is being observed from the Rappahannock/Potomac to the
bay side of the MD Eastern Shore with the evening`s high tide
cycle. Sites farther south mainly saw minor flooding this
afternoon. Additional moderate flooding is expected across the
tidal Potomac/Rappahannock and bay side of the MD eastern shore
through Tuesday as winds veer to the E-SE and long period
easterly swell remains in place over the ocean, allowing water
trapped in the Bay to shift northward. As such, Coastal Flood
Warnings remain in effect through Tuesday evening.

Went ahead and converted the remaining warnings farther south to
Coastal Flood Advisories, which run through the Tuesday
aftn/evening high tide cycle. While localized moderate flooding
is possible at Bayford tonight and Tuesday, Kiptopeke/Oyster
will only see minor flooding so feel an advisory is fine for the
VA Eastern Shore. Elsewhere in the advisory area, only minor
flooding is expected through Tuesday. Don`t have any headlines
for the MD Beaches, inland Worcester County, and Eastern
Currituck County...but may levels may approach minor flood
thresholds on Tuesday with the higher of the two astronomical
tides.

Water levels should gradually fall this week with decreasing
astronomical tides, but minor flooding is expected through much
of the week in areas near/adjacent to the mid/upper bay.


As of 345 AM EDT Monday:

Consecutive high tides reaching at least Minor Flood with this event:

- Lewisetta (P.O.R. since 1979): 13 (with several more to come),
  previous record was 8 in Oct 2021, Oct 2019, Oct 2015.

- Cambridge (P.O.R. since 1980): 7 (with several more to come),
previous record was 5 in Oct 2021, Oct 2019, Sep 2018, Oct  2011.

Consecutive high tides reaching at least Moderate Flood with this
event: (this event is unlikely to break records listed).

- Lewisetta (P.O.R. since 1979): 3 (so far), ***record is 7 in  Oct
2015***

- Cambridge (P.O.R. since 1980): 1 (so far), ***record is 4 in  Oct
2019***

In addition, a High rip current risk is in effect today and Monday.
A High rip current risk will likely continue through at least
Tuesday.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Warning until 2 AM EDT Wednesday for MDZ021>023.
NC...None.
VA...Coastal Flood Warning until midnight EDT Tuesday night for
     VAZ075-077.
     Coastal Flood Warning until 10 PM EDT Tuesday for VAZ076-078-
     085-521-522.
     Coastal Flood Advisory until 9 PM EDT Tuesday for VAZ083-518-
     520.
     Coastal Flood Advisory until 6 PM EDT Tuesday for VAZ084-086-
     095>098-523>525.
     Coastal Flood Advisory until 10 PM EDT Tuesday for VAZ089-090-
     093-099-100.
MARINE...Small Craft Advisory until 6 PM EDT Wednesday for ANZ650-652-
     654-656-658.

&&

$$

SYNOPSIS...AJZ/AM
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...KMC
AVIATION...KMC
MARINE...RMM
TIDES/COASTAL FLOODING...AKQ