-- Discussion containing changed information from previous version are highlighted. --
139
FXUS61 KAKQ 221944
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
344 PM EDT Sun Sep 22 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 on and off
rain chances. Seasonal temperatures are expected to start this
week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 330 PM EDT Sunday...

Key Message:

- Partial clearing this evening with a potential for stratus and
  patchy fog over the Piedmont later tonight.

Surface high pressure is centered over Atlantic Canada this
afternoon and is ridging SW along the Mid-Atlantic coast.
Meanwhile, low pressure lingers offshore. A backdoor cold front
has pushed SE through the area. Aloft, a trough/upper low is
offshore with a building ridge over the Ohio Valley. Mostly
cloudy to overcast in easterly flow behind the backdoor front
with temperatures in the lower to mid 70s. Mainly dry, although
a slight chc of light showers/sprinkles will linger in vicinity
of the I-95 corridor through late afternoon. Some clearing is
expected along the coast this evening and overnight. Brief
partial clearing is possible farther inland later this evening
into the early overnight hours. However, stratus and some patchy
fog are expected to develop later tonight into early Monday
morning. Forecast lows tonight are mainly in the upper 50s to
lower 60s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
As of 330 PM EDT Sunday...

Key Messages:

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

- Low end chances for showers Monday night into Tuesday and
  again Wednesday.

Low pressure slides SE well off and farther away from the coast
Monday into Tuesday as the upper ridge builds SE into the
Southeast CONUS. Surface high pressure centered well NE of the
region will continue to build SW along the coast. Mainly dry
Monday, although a shortwave trough will bring a chc of showers
Monday night into Tuesday, and a slight chc of tstms Monday
evening and Tuesday afternoon and evening over the Piedmont.
High pressure at the coast will generally confine rain chances
to the western half of the area. The upper ridge amplifies off
the Southeast coast Wednesday. However, our western and northern
counties will still be close enough to the northern periphery
of the ridge for a chc of showers (and a slight chc of tstms) to
continue. There will be a considerable amount of cloud cover
Monday through Wednesday, especially NW. Highs Monday will
mainly be in the mid to upper 70s. Thicker cloud cover has the
potential to keep the NW counties in the upper 60s to around 70F
Tuesday, with lower to mid 70s elsewhere. By Wednesday, highs
push into the mid 70s NW to the lower 80s SE as the upper ridge
amplifies. Lows will mainly be in the 60s Monday through
Wednesday mornings.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 330 PM EDT Sunday...

Key Messages:

- Multiple low-end chances for precip late next week into early
  next weekend with low confidence in regard to the eventual
  evolution of a tropical system in the Gulf of Mexico.

There is an increasing chc of tropical development in the NW
Caribbean and Gulf of Mexico Monday through Wednesday. However,
there is low confidence on how the potential system and mid-
latitude jet interact by late week into next weekend. The
general trend amongst the 12z/22 models is for the tropical low
to move into the mid-South while an upper low dives SE off the
New England coast, and high pressure nudges into the northern
Mid-Atlantic. This would generally keep much of the moisture SW
of the area, with some rain trying to nudge in from the SW
Friday into Saturday. At this time, PoPs are generally at or
below 20% for the late week into next weekend (highest SW albeit
still low), with seasonal high temperatures in the mid 70s to
around 80F and lows in the upper 50s to mid 60s.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
As of 200 PM EDT Sunday...

High pressure continues to be centered over Atlantic Canada as
of 18z and is ridging SW along the Mid-Atlantic coast.
Meanwhile, a backdoor cold front has pushed through the area.
Cigs are primarily MVFR with an ENE wind of 5-10kt. Cigs are
expected to slowly improve to VFR through the aftn with some
clearing by this evening, especially toward the coast. MVFR/IFR
cigs are expected to develop inland late tonight into early
Monday morning with the best likelihood of flight restrictions
at RIC. Additionally, vsby potentially falls to 3-5sm at RIC.
High pressure remains in vicinity of the coast Monday. Dry and
VFR Monday late morning into the aftn with increasing clouds as
an upper level impulse approaches from the NW. The wind will be
SE 5-10kt inland and ENE 5-10kt along the coast.

There is a chc of showers Monday night into Tuesday, especially
well inland away from the coast. Minimal chcs of showers persist
Tuesday through Friday. Generally VFR outside of any late
night/early morning fog/stratus.

&&

.MARINE...
-- Changed Discussion --
As of 340 PM EDT Sunday...

Key Messages:

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

-A Small Craft Advisory is in effect for the mouth of the bay through
 1 AM tonight for elevated waves.

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

-Northeast winds may become elevated next weekend.

Sfc low pressure lingers well off the Mid Atlantic and New England
coast, with high pressure centered well to the north, across
northern Quebec and New Brunswick. Winds were generally E/NE 10-15
kt with occasional gusts up to 20 kt across the local waters this
afternoon. The pattern does not change much over the next couple of
days with winds remaining 10-15 kt through Mon, diminishing to ~10
kt Tue. Winds remain sub SCA level (mainly SE) through Thu before
becoming NE Fri. Models are coming into better agreement regarding
an enhanced NE flow developing next weekend with SCA winds possible.
We will continue to monitor and see how this trends.

Waves and seas were generally 1-2 ft (2-3 ft across the lower bay
and 3-4 ft across the mouth of the bay) and 4-6 ft respectively this
afternoon. Expect seas to remain elevated (4-7 ft) into at least the
middle of the week (and possibly through next weekend). For now,
have extended SCAs across the coastal waters through Tue with future
extensions likely. Have also added a SCA for the mouth of the bay as
waves at the First Landing buoy have been 4-5 ft this
afternoon. While these wave heights are locally high compared to
nearby buoy observations, at least 3-4 ft waves at the mouth of
the bay appear likely to continue into this evening. As such,
SCAs here are in effect until 1 AM tonight.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
As of 340 PM Sunday...

- Key Message: Long duration coastal flood event continues
  across the region, with water levels expected to peak this
  afternoon and Monday. 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 are currently running +1.5 ft to +2.0 ft above
astro tide levels. The high tides this afternoon and Monday
afternoon/evening look to be the highest with locally moderate
coastal flooding possible across much of the coastal waters. In
general, the most widespread moderate flooding (potentially near
Major at a few places) will be over the mid/upper Bay, including the
tidal Potomac/Rappahannock and the MD eastern shore through Monday
evening. These locations may see moderate coastal flooding continue
into 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 have been
extended through Tuesday evening.

Areas to the south across the lower Bay/tidal James and York rivers
will be more marginal, with peak water levels mostly in the high end
minor flood to locally moderate thresholds. However, given that
tidal anomalies remain fairly consistent, Monday`s high tide
should be comparable to this afternoon`s high tide. As such,
have extended Coastal Flood Warnings here through Monday
afternooon`s high tide.

Have opted to leave Norfolk and Chesapeake in a Coastal Flood
Advisory (as opposed to a Coastal Flood Warning) given that the
Elizabeth River and Sewell`s Point still look to remain below
moderate flood stage. A Coastal Flood Advisory also remains across
the Atlantic side of the Maryland Eastern Shore with Ocean City
looking to remain in minor flood stage through Monday afternoon.
Additional headlines are likely to be needed for Tuesday and
Wednesday in spots, but uncertainty is higher than for Monday across
the middle and lower bay.

In addition, a High rip current risk is in effect through Monday.
This may need to be extended for Tuesday.
-- End Changed Discussion --

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Warning until 2 AM EDT Wednesday for MDZ021>023.
     Coastal Flood Advisory until 4 PM EDT Monday for MDZ024-025.
NC...Coastal Flood Warning until 4 PM EDT Monday for NCZ102.
VA...Coastal Flood Warning until 4 PM EDT Monday for VAZ098.
     Coastal Flood Warning until midnight EDT Tuesday night for
     VAZ075-077.
     Coastal Flood Warning until 10 PM EDT Tuesday for VAZ076-078-
     085-521-522.
     Coastal Flood Advisory until 9 PM EDT Tuesday for VAZ083-518-
     520.
     Coastal Flood Warning until 6 PM EDT Monday for VAZ084-086-
     523>525.
     Coastal Flood Warning until 10 PM EDT Monday for VAZ089-090-
     093-096.
     Coastal Flood Advisory until 6 PM EDT Tuesday for VAZ095-097.
     Coastal Flood Warning until 8 PM EDT Monday for VAZ099-100.
MARINE...Small Craft Advisory until 1 AM EDT Monday for ANZ634.
     Small Craft Advisory until 6 PM EDT Tuesday for ANZ650-652-654-
     656-658.

&&

$$

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