-- Discussion containing changed information from previous version are highlighted. --
635
FXUS61 KAKQ 250753
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
353 AM EDT Wed Sep 25 2024

.SYNOPSIS...
A series of shortwave troughs will slide across the region in
northwest flow aloft bringing unsettled conditions through
midweek. The remnants of Helene likely pass well west of the
area on Friday. Temperatures will gradually moderate through
midweek.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 335 AM EDT WEDNESDAY...

Key Messages:

- Showers and thunderstorms will persist through the early morning
hours

-Another batch of showers will move through the CWA late this morning

Latest early morning surface analysis shows the strong high pressure
1026mb+ over the northeastern Canada. Aloft, weak to moderate 850mb
winds continue to fetch in an abundance of moisture across the CWA
helping to fuel these showers and thunderstorms early this morning.
Throughout this morning a mass of showers and thunderstorms have
tracked along a stationary boundary across southern Virginia and
northeastern North Carolina. As of 245am another round of showers
and thunderstorms have started to initiate across north central
North Carolina and are now slowly making their way into the far south
western region of the CWA. These showers will bring moderate to
heavy rain across the area as some higher level instability (roughly
500-1000 MUCAPE) remains in place. With a conducive environment for
heavy rain and an already saturated area the flood watch will remain
in place till 12 this morning. Latest model guidance and real time
observations suggest that the flood watch will not need to be
extended past that time. The abundant cloud cover this morning has
allowed our temperatures to remain in the middle to upper 60s in
land and lower 70s along the coast.

The stationary boundary will lift later this morning allowing
showers and thunderstorms to track across the CWA. The main threat
from these showers and storms will be heavy rain and gusty winds.
The best chance for showers and thunderstorms will be along and west
of I-95 late this morning and early afternoon. High temperatures
today will range from the mid-upper 70s north to the lower 80s south.
Then for tonight lows will be back into the middle to upper 60s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
As of 335 AM EDT WEDNESDAY...

Key Messages:

- The remnants of Helene move north Thursday night through Friday,
bringing additional rain chances to the area.

Thursday will be the driest day out this week. Pops remain(5-10%)
low across the coast with a higher chance of pops (25-35%) across
the far western fringes of the CWA. Then the chances of pops
increase by friday morning and afternoon. There is still some small
uncertainty on how far the rain bands of Tropical Cyclone Helene
will extend northeast. As of now, the best chances of pops (60-70%)
remain along and west of I-95 on Friday. Friday also has the
potential of severe weather across far southern Virginia and
northeastern North Carolina. The main threat will be tornadoes
that will be associated with TC Helene. Right now, the SPC has
issued a marginal risk across southern Virginia and northeastern
North Carolina. Then by Saturday morning the remnants of TC
Helene will have moved off to the west lowering the chances of
pops. Sky cover for these couple of days will remain mostly
cloudy. Temperatures will warm back up into the lower 80s for
Thursday. Then by friday temperatures will range between the
middle 70s to lower 80s across the CWA.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 335 AM EDT WEDNESDAY...

Key Messages:

- Multiple low-end chances of rain late this week into the
  weekend from Tropical Storm Helene

- Drier and cooler air coming mid next week

Latest ensemble guidance indicated that Tropical Storm Helene will
move across portions of the southeast and stall over the central
ohio river valley by Saturday. This system will then move back across
the area as an upper level low. With the residual energy and moisture
on Saturday, Sunday, and Monday.Temperatures Saturday and Sunday
will have highs in the upper 70s and lows in the low to mid 60s. The
last of the moisture will be squeezed out on Tuesday by a frontal
passage which will bring drier and cooler conditions Tuesday and
Wednesday with highs in the mid 70s and lows around 60F.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
As of 200 AM EDT Wednesday...

A batch of Showers and isolated tstms are continuing to move
across southern Virginia. These showers and thunderstorms will
bring some MVFR and IFR conditions for ECG, ORF, and PHF this
morning. Later this morning there will be another chance of
isolated showers and thunderstorms across all TAF sited bringing
in more MVFR and IFR conditions. Then by this afternoon as the
warm front propagates north mainly MVFR and VFR conditions
across all taf sites as the chances of showers decrease.
Thursday will be drier, but chances of showers return on Friday
and Saturday.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
As of 350 AM EDT Wednesday...

Key Messages:

- Small Craft Advisories have been extended into early Friday for
  all Atlantic zones due to persistent seas above 5 ft.

- Southeast winds increase on Friday bringing the potential for Small
  Craft conditions in the Chesapeake Bay, lower James River,
  and Currituck Sound.

1028mb high pressure remains over eastern Canada, ridging southward
into the Mid-Atlantic states between low pressure well offshore and
another low over Michigan. TC Helene continues to move northward
through the Yucatan Channel and into the Gulf of Mexico today. Winds
this morning are generally SE at 10-15 kt. Waves in the bay are 1-3
ft (highest near the mouth) while seas offshore range from 4-6 ft.

Persistent swell will keep seas aoa 5 ft through the week and likely
through the weekend as well as onshore flow continues. Extended the
offshore SCA headlines into Friday morning with this package and
further extensions are likely in subsequent forecasts. SE winds stay
below SCA thresholds today and Thursday but are expected to increase
to 15-20 kt with gusts to 25 kt by late morning or early afternoon
Friday as what`s left of Helene makes its closest approach to the
region. SCAs are looking increasingly likely for the Ches Bay as
well as the lower James River and Currituck Sound into early
Saturday before winds decrease to 10-15 kt. Waves near the mouth of
the bay will also increase to 3-4 ft during this period. Additional
SCA headlines are possible Sunday into early next week as remnant
energy from Helene`s circulation and an upper trough foster the
development of low pressure near the Carolina coast with high
pressure stationed well north of the area, resulting in enhanced
onshore flow once again.

High rip current risk continues for all beaches today and Thursday
with swell periods 10-12 seconds.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
As of 350 AM EDT Wednesday...

Key Messages:

- Long duration coastal flood event has started to wind down
  across the region. Water levels are forecast to continue to
  subside over the next few days.

- Coastal Flood Advisories have been issued for the next few
  tide cycles for bay side portions of the MD Eastern Shore,
  tidal Potomac and Rappahannock, and the VA Eastern Shore.

Tidal departures are averaging 1.5-2 ft above astro tides this
morning. Minor tidal flooding is forecast in the upper bay and along
the Potomac/Rappahannock, including on the bay side of the MD
Eastern Shore, through tonight`s high tide cycle. Accordingly,
Coastal Flood Advisories have been issued for these areas through
late tonight. Elsewhere, mainly nuisance coastal flooding is
expected today.

Water levels should continue to gradually fall this week with
decreasing astronomical tides, but minor flooding is expected mid to
late week in areas near/adjacent to the mid/upper bay. Over the
lower bay, only nuisance/action-level is expected.

As of 350 AM EDT Wednesday:

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

- Lewisetta (P.O.R. since 1979): 16 (with a few more to come),
  previous record was 8 in Oct 2021, Oct 2019, Oct 2015.

- Cambridge (P.O.R. since 1980): 11 (with water levels likely to
  fall short of minor flood for the next high tide), previous
  record was 5 in Oct 2021, Oct 2019, Sep 2018, Oct 2011.

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

- Lewisetta (P.O.R. since 1979): 7 (with additional moderate
  flood unlikely), ***tying the record of 7 in Oct 2015***
-- End Changed Discussion --


&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Advisory until 2 AM EDT Thursday for MDZ021>023.
NC...None.
VA...Flood Watch until 8 AM EDT this morning for VAZ060-065>067-079.
     Coastal Flood Advisory until 10 PM EDT this evening for VAZ075-
     077-099-100.
     Coastal Flood Advisory from 7 AM this morning to 1 AM EDT
     Thursday for VAZ076-078-085-521-522.
MARINE...Small Craft Advisory until 7 AM EDT Friday for ANZ650-652-654-
     656-658.

&&

$$

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