694
FXUS61 KAKQ 250737
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
337 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. Then by Saturday morning
the remnants of TC Helene will move off 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/...
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 VRF conditions
across all taf sites as the chances of showers decrease.
Thursdaywill be drier, but chances of showers return on Friday
and Saturday.

&&

.MARINE...
As of 400 PM EDT Tuesday...

Key Messages:

- Elevated seas persist through most of this week and into the
coming weekend. Small craft advisories have been extended on the
coastal waters through Thursday.

- The remnants of Tropical Cyclone Helene pass well inland Friday,
with impacts locally limited to gusty SE winds Friday-Friday night.

A warm front is located SW of the waters this afternoon, with low
pressure well offshore and high pressure ridging into the area from
New England. Tropical Storm Helene is situated over the NW Caribbean
Sea and is expected to track northward into the Gulf Mexico tonight,
per the latest NHC forecast. Locally, a relaxed pressure gradient is
leading to light-moderate winds as of 3 PM/19z, generally E ~10
kt. Seas remain elevated in the 4.5-7 ft range, highest N.
Small craft advisories remain in effect for all coastal water
zones and have been extended through most of Thursday as
confidence is high in these elevated seas continuing.

The eastern fringes of a LLJ overspreads the Chesapeake Bay tonight
and winds likely increase to 10-15 kt for a time after sunset. There
could be a few gusts to 20-25 kt in this timeframe, especially
across the northern bay. The duration and marginal wind speeds
precludes a small craft advisory at this time. Into Wednesday,
the high over New England retreats into the Canadian Maritimes
as TS or Hurricane Helene gets pulled northward through the
central and eastern Gulf. This will turn the flow to the SE or
SSE through at least Thursday, though wind speeds should average
10 kt or so. Helene makes landfall in the FL Big Bend region
Thursday, tracking inland along the southern Appalachians
Friday. The remnant low will probably lead to an increase in SE
winds by Friday afternoon and winds could approach low-end SCA
criteria of 15-20 kt with gusts to 25 kt. This appears most
likely over the southern coastal waters and lower Chesapeake
Bay, with lower chances further N. There is higher uncertainty
into Saturday as a cold front potentially pushes into the area
from the N or NW. The timing is overall slower with the 12z
guidance, delaying any increase in winds to Saturday night or
early Sunday. SCA conditions are possible behind this front as
NE winds make a return.

Seas remain 4-6 ft through most of this week and into the weekend
and SCAs will likely be needed for most of this period. Waves in the
Chesapeake Bay will average 1-2 ft through the weekend, except ~3 ft
at the mouth of the bay. Per the latest 12z NWPS output, 3-4 ft
waves are possible at the mouth of the bay tonight w/ the brief
increase in SE winds. Not enough confidence at this time to issue a
SCA, however. Depending on the frontal timing Sat-Sun, waves in the
bay could increase to 3-4 ft at times.

A high rip current risk is forecast through at least Wednesday.

&&

.TIDES/COASTAL FLOODING...
As of 400 PM 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).

- Water levels are forecast to gradually subside over the next few
days.

- Coastal Flood Warnings remain in effect from Windmill
Pointt/Tappahannock northeastward to the bay side of the MD Eastern
Shore, with advisories elsewhere (see CWFAKQ for more details).

- Minor flooding likely persists into Wednesday across the middle
and upper bay.

Tidal departures are averaging 1.5-2 ft above astro tides this
afternoon. Only changes to the ongoing headlines was to refine the
timing with the ongoing or approaching afternoon/evening high tide.
High-end minor or low-end moderate tidal flooding is forecast in the
upper bay and along the Potomac/Rappahannock, including on the bay
side of the MD Eastern Shore, with this upcoming high tide cycle.
Accordingly, Coastal Flood Warnings remain in effect through this
evening (early Wed morning on the MD Eastern Shore).

Elsewhere, Coastal Flood Advisories are in effect across the lower
bay and York and James Rivers through this evening. Here, confidence
is low in exceeding minor flood and current tidal departures argue
water levels should peak within or below minor thersholds. Elsewhere
in the advisory area, only minor flooding is expected today. Also,
included MD Beaches in the ongoing advisory through 6 PM as Ocean
City crested just above minor flood w/ this afternoon`s high tide.

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. Over the lower
bay, only nuisance/action-level at worst is expected.

As of 400 PM EDT Tuesday:

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

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

- Cambridge (P.O.R. since 1980): 10 (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 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...MAM/SW
TIDES/COASTAL FLOODING...