102
FXUS61 KAKQ 211935
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
335 PM EDT Sat Sep 21 2024

.SYNOPSIS...
High pressure builds south along the Mid-Atlantic coast into
early next week. Meanwhile, a series of shortwave troughs will
slide across the region in northwest flow aloft bringing on and
off rain chances. Seasonal temperatures are expected to start
next week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 335 PM EDT Saturday...

Key Messages:

- Pleasant weather this afternoon with highs in the low 80s
  inland, 70s immediately near the coast.

- Shower/storm chances increase late this afternoon in the
  west, progress east overnight. A severe storm or two possible
  in the piedmont.

Mostly sunny this afternoon with high pressure centered well N
of the region and ridging S along the Mid-Atlantic coast.
Temperatures range from the upper 70s to lower 80s. Meanwhile,
showers/tstms are developing across the higher terrain to the W
ahead of a shortwave trough and approaching cold front.21/12z
CAMs remain in good agreement regarding timing and coverage of
precip spreading across western portions of the area late this
afternoon and evening. Scattered showers/storms then gradually
cross the area overnight as secondary shortwave energy slides
across the area. SPC has far western portions of the area in a
MGNL for today. There will be decent shear in the area, as the
12z HREF shows ~30-35kt of effective shear. However, the window
for severe weather will be limited given the narrow timeframe
for sufficient CAPE prior to sunset. If severe tstms do form,
the threats would be damaging wind gusts and hail. A weak
backdoor cold front pushes onshore late tonight. There is a
potential for stratus late tonight, and some patchy fog across
the Piedmont. Low temperatures will primarily be in the 60s.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
As of 335 PM EDT Saturday...

Key Messages:

- Isolated shower chances for Sunday with a backdoor cold front

- Pleasant start to the week with dry weather and highs in the
  70s

The backdoor cold front is forecast to cross into the local
area early Sunday morning and lingers in the area through the
day. Isolated/widely scattered showers will accompany the front,
so slight chance PoPs have been maintained in the NE early then
progressing SW through the day. High temperatures will depend
on the location of the front through the day, but generally
expect low-mid 70s in the NE and around 80F in the SW. Mostly
cloudy to overcast conditions are expected across most of the
area.

The ridge axis aloft shifts toward the E coast Monday.
Meanwhile, surface low pressure offshore finally makes some
progress to the SE and farther offshore. Monday should be
pleasant, albeit a bit cloudy. Highs will be in the low-mid 70s
across northern counties and upper 70s S of I-64. Lows Mon night
will be around 60. Another shortwave trough approaches from the
NW Tuesday as high pressure remains centered NE of the region
with the surface ridge axis extending SW along the Mid-Atlantic
coast. This will bring a chc of showers inland. High
temperatures range from the lower 70s NW to the upper 70s SE,
after morning lows in the lower to mid 60s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 335 PM EDT Saturday...

Key Messages:

- Multiple low-end chances for precip next week.

Moisture will gradually slide back into the area next week
around the edge of a ridge offshore, and ahead of a trough well
to the W. Confidence in the forecast for midweek and after is
low, but there are daily rain chances with increased moisture.
Temperatures will gradually warm a bit as thicknesses rise with
the ridge pushing up the coastline. Highs are forecast to be in
the mid 70s to around 80 degrees. Lows will mainly be in the
60s.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
As of 210 PM EDT Saturday...

Surface high pressure remains over the region as of 18z between
low pressure offshore and a cold front over the upper Ohio
Valley. FEW-SCT CU with bases of 3-4kft and a light and variable
wind. The cold front and an upper trough will approach from the
NW later this aftn and evening. Then a backdoor cold front will
slide in from the NE late tonight into early Sunday morning. The
best chc of showers/tstms will be at RIC this evening and mainly
after 23z. Brief heavy rain and reduced vsby along with locally
strong wind gusts are possible with any tstms. A chc of showers
and perhaps a tstm will shift E later tonight, mainly after 04z.
There is a potential for MVFR and IFR cigs late tonight into
Sunday morning, with the best potential for IFR cigs at RIC.
Additionally, MVFR vsby is possible. The backdoor cold front
will slide across the region Sunday. MVFR cigs potentially
linger into late morning and early aftn, with VFR by late aftn.
The wind will mainly be ENE 8-12kt behind the backdoor front.

There is a potential for lower cigs late Sunday night/early
Monday morning. Otherwise, mainly dry and VFR Monday. Minimal
chcs of showers are forecast Tuesday through Thursday.

&&

.MARINE...
As of 430 AM EDT Saturday...

Key Messages:

- Small Craft Advisories remain in effect for all coastal waters
  through Monday (primarily for seas).

- Winds increase Sunday, but remain mainly sub-SCA. Waves may
  build to 4 ft late Sunday/Sunday night at the mouth of the
  Bay.

- Persistent long period swells keep seas elevated into the
  middle of next week.

Sfc low pressure (~1005mb) lingers well off the southern New
England and NJ coast, with high pressure centered well to the
N, across NewFoundland/Labrador. A weak area of low pressure is
situated across the Great Lakes. The stronger pressure gradient
remains offshore, with fairly light northerly winds across the
local waters. SCA headlines remain in effect for all coastal
waters for 5-7 ft seas, but winds will be light and variable
5-10 kt or less this morning, before becoming SE 10-15 kt this
evening. While a few gusts up to 20 kt will be possible this
evening, especially across the upper bay and rivers, this is
unlikely to be widespread and of sufficient duration to warrant
any headlines. The low from the Great Lakes weakens while
pushing through the northern mid- Atlantic region Sunday, with
high pressure to the north sinking SSW as a backdoor cold front
later Sunday/Sunday night. There is still a decent surge of NE
winds expected Sunday, but pressure rises are rather minimal so
wind probs for SCA thresholds remain low (~15 kt with occasional
gusts up to 20 kt across the lower bay as opposed to sustained
15-20 kt). Confidence is still too low for any headlines
(outside of 3-4 ft waves at the mouth of the Ches Bay). A slow
improvement is expected by mid week, though SCAs for seas are
still probable into at least early Wed given the long period
easterly swell.

&&

.TIDES/COASTAL FLOODING...
As of 430 AM Saturday...

- Key Message: Long duration coastal flood event ongoing across
  the region, with flooding likely to persist through at least
  late Monday. Various headlines remain in effect (see latest
  CFWAKQ for details).

 Tidal departures have risen slightly over the past 12 hrs,
with some areas now >+1.5 ft above astro tide levels. The
upcoming high tide cycle later today is the higher of the daily
cycle (astronomically), which will lead to water levels into
moderate flood thresholds for most sites in the mid/upper Bay,
as well as the VA eastern shore. It is more marginal, but close
for Va Beach and Currituck NC. In these areas have upgraded to a
Coastal Flood Warning (lingering through late Sunday except at
VA Beach/NC where the Warning is for today only). For most
places along the western shore of the lower Bay, levels are
currently forecast to stay capped at Minor Flood thresholds
today and Sunday. Decided to extend the Advisories, but leave
the Watch in effect for Sunday given some uncertainty
(to account for the possibility of the E/NE wind surge
over-performing on Sunday). Additional headlines will likely be
needed Monday, possibly even through Tue-Wed.

In addition, a High rip current risk is in effect through
Saturday and will likely be extended into Sunday as well.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Warning until midnight EDT Monday night for
     MDZ021>023.
     Coastal Flood Advisory until 4 PM EDT Monday for MDZ024-025.
NC...Coastal Flood Warning until 4 PM EDT Sunday for NCZ102.
VA...Coastal Flood Warning until midnight EDT Monday night for
     VAZ075-077.
     Coastal Flood Warning until 4 PM EDT Sunday for VAZ098.
     Coastal Flood Warning until 10 PM EDT Monday for VAZ076-078-
     085-521-522.
     Coastal Flood Advisory until 8 PM EDT Monday for VAZ083-518-
     520.
     Coastal Flood Advisory until 4 AM EDT Sunday for VAZ084-086-
     523.
     Coastal Flood Warning from 11 AM to 6 PM EDT Sunday for VAZ084-
     086-523>525.
     Coastal Flood Advisory until 6 AM EDT Sunday for VAZ089-090-
     093-096-524-525.
     Coastal Flood Warning from 11 AM Sunday to 10 PM EDT Monday
     for VAZ089-090-093-096.
     Coastal Flood Advisory until 6 PM EDT Monday for VAZ095-097.
     Coastal Flood Warning until 8 PM EDT Monday for VAZ099-100.
MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ650-652-654-
     656-658.

&&

$$

SYNOPSIS...AJZ/AM
NEAR TERM...AJZ/AM
SHORT TERM...AJZ/AM
LONG TERM...AJZ/AM
AVIATION...AJZ
MARINE...LKB/RMM
TIDES/COASTAL FLOODING...AKQ