683
FXUS61 KAKQ 241950
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
350 PM EDT Tue Sep 24 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 AM WEDNESDAY MORNING/...
As of 350 PM EDT Tuesday...

Key Messages:

- Scattered showers and widespread clouds through this evening.

- Additional rain (and isolated thunderstorms) overspreads the
region this evening and continues through tonight.

- A Flood Watch is in effect for our southwestern counties later
this evening through tonight.

This afternoon, strong ~1024mb high pressure is centered over
northeastern Canada, wedging down into the local area. Meanwhile,
weak low pressure is located near the Great Lakes. A stationary
boundary is draped south and west of our local area. As low pressure
begins to lift further to the northeast overnight, the boundary will
slowly try to lift north into the region as a warm front.

Widespread clouds and scattered rain showers and drizzle/mist
remains across the area this afternoon. The current round of light
to moderate showers should continue to push off to the northeast and
gradually diminish over the next few hours, with a small amount of
drying late this afternoon into the early evening. Clouds, rain, and
an onshore wind have kept temperatures cool this afternoon, with
readings generally in the mid-upper 60s to lower 70s. A second wave
of showers (and isolated thunderstorms) is expected to develop and
move through the western half of the area later this evening through
tonight. This second round could produce locally heavy rainfall,
with many of the CAMs hinting showing higher QPF amounts across our
far southwestern counties. As a result, WPC has highlighted these
locations with a slight risk for excessive rainfall for tonight.
After collaborating with neighboring offices, a Flood Watch has been
issued for Prince Edward, Nottoway, Brunswick, Lunenburg, and
Mecklenburg. Scattered instances of flash flooding are possible,
especially in any poor drainage areas. There is a marginal risk for
excessive rainfall for much of the remainder of the area roughly
around I-95 and west. Low temperatures tonight will generally be in
the mid to upper 60s.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
As of 350 PM EDT Tuesday...

Key Messages:

- Continued cloudy conditions with additional chances for showers or
thunderstorms on Wednesday, especially west of I-95.

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

A warm front lifts north through the area tomorrow, bringing warmer
and more humid air back into the region. Additional shower and
storms will be possible Wednesday afternoon, especially along and
west of I-95. Heavy rainfall and potentially gusty winds will be
possible with any storms that develop. High temperatures tomorrow
will range from the mid-upper 70s north to the lower 80s south.
Drier on Thursday, with only low-end PoP chances (mainly west), but
still remaining fairly cloudy. Highs will range from the upper 70s
to lower 80s. Rain chances increase again Thursday night into Friday
as Helene moves north (remaining well west of the forecast area).
The best rain chances will likely be late in the day and Friday
night, with locally rainfall again a possibility (especially west).
Highs on Friday range from the mid 70s NW to lower 80s SE.
&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 350 PM EDT Tuesday...

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

There is some uncertainty about impacts from newly-named Tropical
Storm Helene for the weekend. The 12z ECMWF and GFS suggest remnants
split from Helene`s original track up GA to the W near the TN/MO
border and E over the ocean late Friday. The splitting of the low
pressure system could allow chc showers from 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 /20Z TUESDAY THROUGH SUNDAY/...
As of 200 PM 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.
     Flood Watch from 8 PM EDT this evening through Wednesday
     morning for VAZ060-065>067-079.
     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 8 PM EDT this evening for VAZ083-
     095>100-518-520.
     Coastal Flood Advisory until 10 PM EDT this evening for VAZ089-
     090-093.
MARINE...Small Craft Advisory until 7 PM EDT Thursday for ANZ650-652-
     654-656-658.

&&

$$

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