052
FXUS61 KAKQ 241756
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
156 PM EDT Tue Sep 24 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 /UNTIL 6 PM THIS EVENING/...
As of 330 AM EDT Tuesday...

Key Message:

- A chance for showers lingers through Tuesday morning.

- Chance of showers decrease by this afternoon.

Latest surface analysis this morning shows a moderately strong
surface low far off the eastern coast of the United States, and a
strong high pressure (1024+) over far northeastern Canada. Cloud
cover is continuing to persist this morning keeping temperatures in
the middle to upper 60s and some lower 60s in the far northwestern
portion of the CWA. Some light showers are continuing to track
eastward across southern Virginia as of 2:45 AM.

A weak upper ridge axis has shifted toward the Mid atlantic early
this morning, with additional shortwave energy rounding the northern
periphery of the ridge. Sctd showers will continue to develop along
and W of the I-95 corridor. PoPs diminish Tuesday afternoon, as
shortwave energy lifts northeast of the local area. There is the
possibility of a few rumbles of thunder, with some elevated
instability. The threat for severe storms will be halted for the
most part due to and abundance of cloud cover and lack of sunshine.
The best chance of severe weather will be west of the CWA where the
better instability will reside. Skies will remain mostly cloudy
to cloudy all day and this will again keep temperatures
relatively cool. Highs across the area will be in the lower to
middle 70s (upper 60s possibly in the far northwestern part of
the CWA).

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
As of 330 AM EDT Tuesday...

Key Messages:

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

A weak surface low pressure system will continue to linger north
today across Illinois and Indiana as it tracks into the Great Lakes
region by tomorrow. This system will move a weak boundary north late
Tuesday increasing the chance of showers primarily along and west of
I-95. Pops have been increased to 50-70% west of I-95. 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. Will note, some
of the HIRES model guidance has suggested that some of these storms
could potentially bring gusty winds and heavy rain as some better
lower level instability is brought in. 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 /FRIDAY THROUGH TUESDAY/...
As of 330 AM EDT Tuesday...

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 best chance of showers (especially to the SW of the
local area) around 40-50%. However, there is still 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. Will note, the latest 00z ensemble
guidance has reasonable 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. e 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 through Tuesday.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 200 AM EDT Tuesday...

MVFR CIGs continue with slight showers across the area and into this
evening. Some local IFR is possible. Continued rain chances
overnight around the major airports. MVFR CIGs will remain.
Winds will be ESE around 5-10 kt.

Chc of showers remain Wed (esply inland/RIC). MVFR and locally IFR
CIGs are possible. Thur is drier, but chc of showers returns on Fri
and Sat.

&&

.MARINE...
As of 345 AM EDT Tuesday...

Key Messages:

- Small Craft Advisories remain in effect for all Atlantic
  coastal waters and have been extended into early Thursday due
  to elevated seas.

- Persistent long period swells keep seas elevated through this week
  and likely into the weekend as well.

- East to northeast winds potentially increase this weekend.

Surface high pressure north of New England continues to ridge
southward into the Mid-Atlantic ahead of low pressure centered
over southern Illinois. Aloft, a trough is amplifying over the
Mississippi Valley in response to strong ridging moving into the
Pacific NW. Winds locally remain onshore (NE, E, and SE from
north to south) at 5-10 kt in the Ches Bay and tidal rivers and
closer to 10-15 kt for the Atlantic waters. Waves in the bay are
1-2 ft with 2- 3 ft near the mouth while seas offshore range
from 4-7 ft.

Expect conditions will be similar into this afternoon with winds
increasing to around 15 kt across the local waters by late afternoon
and into the evening hours. A few gusts to ~20 kt are likely during
this period before becoming ESE and falling back to ~10 kts late
tonight into Wednesday. This general pattern will continue through
the week winds expected to remain below SCA thresholds. Uncertainty
increases for Friday into the weekend with respect to track and
local influence from PTC 9/Helene moving northward from the NE Gulf
of Mexico. Will continue with a blended approach for now but the 00z
deterministic runs do show a period of stronger E and NE winds this
weekend as the original circulation passes by well to our
west/southwest and secondary low pressure develops closer to the
region. Local wind probabilities of sustained winds aoa 18 kt
increase above 50% during this period. Waves in the Ches Bay will
average 1-2 ft with 2-3 ft near the mouth of the bay through this
week. A brief period of 3-4 ft waves at the mouth of the bay is
possible this evening but not confident enough in coverage of 4 ft
waves to issue SCAs with this forecast package. Seas will stay above
5 ft for most/all of this week (at least for the offshore half of
the coastal zones) with periods 10-12 seconds. Extended the SCA
headlines for the coastal waters into early Thursday and further
incremental extensions are likely.

High rip current risk continues for all beaches today and
Wednesday.

&&

.TIDES/COASTAL FLOODING...
As of 700 AM EDT Tuesday...

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 today, 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 close to +2.0 ft above astro
tide levels across the region. No major changes to ongoing
coastal flood headlines with this package. Low-end moderate
tidal flooding is forecast for the Potomac to the bay side of
the MD Eastern Shore with the next high tide cycle. Additional
moderate flooding is expected across the tidal
Potomac/Rappahannock and bay side of the MD eastern shore this
evening 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. Accordingly, Coastal Flood Warnings
remain in effect through this evening.

Elsewhere, Coastal Flood Advisories continue or have been extended
through this afternoon/evening high tide cycle except for Yorktown
and the Ware River where confidence in exceeding minor flood
thresholds is low. While localized moderate flooding is possible at
Bayford today, 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 today. Don`t have any
coastal flood headlines for the MD Beaches, inland Worcester
County, and Eastern Currituck County...latest forecast keeps
these locations below minor flood thresholds.

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 700 AM EDT Tuesday:

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

- Lewisetta (P.O.R. since 1979): 15 (with several more to come),
previous record was 8 in Oct 2021, Oct 2019, Oct 2015.

- Cambridge (P.O.R. since 1980): 9 (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 may tie the record at Lewisetta).

- Lewisetta (P.O.R. since 1979): 6 (so far),
   ***record is 7 in Oct 2015***

- Cambridge (P.O.R. since 1980): 1 (so far and unlikely to occur
  on consecutive tide cycles),

  ***record is 4 in Oct 2019***

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Warning until 2 AM EDT Wednesday for MDZ021>023.
     Coastal Flood Advisory until 6 PM EDT this evening for MDZ025.
NC...None.
VA...Coastal Flood Advisory until 6 PM EDT this evening for VAZ084-
     086-523>525.
     Coastal Flood Warning until midnight EDT tonight for VAZ075-
     077.
     Coastal Flood Warning until 10 PM EDT this evening for VAZ076-
     078-085-521-522.
     Coastal Flood Advisory until 9 PM EDT this evening for VAZ083-
     518-520.
     Coastal Flood Advisory until 2 AM EDT Wednesday for VAZ089-090-
     093-095>098.
     Coastal Flood Advisory until 10 PM EDT this evening for VAZ099-
     100.
MARINE...Small Craft Advisory until 7 AM EDT Thursday for ANZ650-652-
     654-656-658.

&&

$$

SYNOPSIS...AJZ/HET
NEAR TERM...HET/TMG
SHORT TERM...AJZ/HET
LONG TERM...KMC
AVIATION...KMC/TMG
MARINE...RHR
TIDES/COASTAL FLOODING...