-- Discussion containing changed information from previous version are highlighted. --
860
FXUS61 KAKQ 240748
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
348 AM 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/...
-- Changed Discussion --
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. Sky`s 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).
-- End Changed Discussion --

&&

.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 MONDAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
As of 200 AM EDT Tuesday...

MVFR CIGs were prevailing across the area this morning. Winds
continue to blow out of the E-SE around 5-10 kt across the
Virginia and North Carolina TAF sites. Winds remain light and
variable around SBY this morning. Some showers continue to
linger across southern Virginia this morning. With more showers
initiating west of I-95 in the far northwestern part of the CWA.


Chc of showers increases into Wed (esply inland/RIC). MVFR and
locally IFR flight restrictions are possible with the chance of
rain Tue and Wed. Thu will be drier, but chc of showers returns
on Fri.

&&

.MARINE...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.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 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 6 PM EDT this evening for VAZ084-
     086-095>098-523>525.
     Coastal Flood Advisory until 10 PM EDT this evening for VAZ089-
     090-093-099-100.
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...HET/KMC
AVIATION...HET/TMG
MARINE...RHR
TIDES/COASTAL FLOODING...