-- Discussion containing changed information from previous version are highlighted. --
869
FXUS61 KAKQ 230805
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
405 AM EDT Mon Sep 23 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 /THROUGH TONIGHT/...
As of 315 AM EDT Monday...

Key Message:

-Cloudy, but overall pleasant day with highs in the 70s.

-A chance for showers tonight, especially west of I-95.


Early morning sfc analysis indicates high pressure centered over New
England/Eastern Canada ridging down the Atlantic coast and into the
local area. Meanwhile, persistent low pressure well offshore is
finally making progress on its journey south. Aloft, a ridge is
nudging into the local area. Through the day today, the ridge axis
aloft will slide in overhead while the sfc high continues to wedge
itself down the coast.

Cloud cover has been a little slow to build back in from the west
tonight. As a result, temps are running a bit cooler than
anticipated between I-95 and the immediate coastal area. Latest obs
show these locations in the upper 50s. Further inland, where clouds
have filled in, temps are in the low-mid 60s. A few obs are showing
fog, but this shouldn`t be as widespread as yesterday morning.
Clouds will stick around through the day, especially inland. Due to
the thicker cloud cover, temps will run on the cooler side with
highs in the low to mid 70s. Warmer in the east with highs in the
mid-upper 70s. Onshore flow continues today, so immediate coastal
areas will also run on the cooler side. Regarding precip, the
daytime hours should largely remain dry, but cannot completely rule
out a stray shower on the western edge of the FA. A weak shortwave
trough will travel up the ridge aloft tonight, which may act to
trigger showers in the area. However, high pressure at the coast
will act to limit precip, especially E of I-95. Have Chc PoPs
entering the western counties late this evening and sticking around
through the night. Lows tonight will be in the low-mid 60s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
As of 400 AM EDT Monday...

Key Messages:

- Cloudy will multiple chances for showers, primarily west of
  I-95.

The synoptic pattern for the Tues-Wed period has become clearer
given the global models coming into better alignment. Tues will be
defined by the ridge aloft amplifying as it nudges offshore and a
trough deepening over the plains. Going into Wed, an UL gets closed
off from the trough and shifts S as a ridge amplifies over the
western CONUS. At the sfc, high pressure from the NE will remain in
control locally while a front approaches from the NW. Shortwaves
will eject out of the trough Tues (and less so Wed), creating
opportunities for precip. Showers will generally stick to western
portions of the area given high pressure in place. Current forecast
has the highest chances for precip during the Tues night period.
PoPs during this time are in the 50-60% range W of I-95 and in the
20-45% range to the E. Mostly cloudy to overcast conditions will
persist through this period. Highs on Tuesday range from the upper
60s in the NW to the mid 70s in the SE. Lows Tues night in the mid
60s. Increased thicknesses will allow for slightly warmer conditions
on Wed with highs in the mid 70s NW and around 80 in the SE.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
-- Changed Discussion --
As of 400 AM EDT Monday...

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.

The start of the long term period will be shaped by what the
potential tropical system in the Gulf does. Confidence in this storm
forming is increasing, but it is still too early to determine
exactly how this storm would interact with the mid-latitude jet
later in the week. The trend so far is holding onto the system
staying well to the SW of the local area while low pressure well to
the N pushes SE off the New England coast. There is decent agreement
between global models that moisture from the system will make it
into at least the SW portion of the FA sometime Thurs night-Fri
night. Have increased to Chc PoPs during this time period. May also
see additional showers over the weekend, but uncertainty is high.

Regarding temps, highs on Thurs are forecast to be in the low-mid
80s, mid-70s to around 80s on Fri, 70s for Sat and Sun. Lows getting
progressively cooler through the period, starting in the upper 60s
Thurs night, then getting down to the 50s-low 60s over the weekend.
-- End Changed Discussion --

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
As of 150 AM EDT Monday...

VFR conditions prevail across the terminals to start the 06z
TAF period as high pressure ridges down the Atlantic coast.
While cloud cover is still expected to increase later tonight,
there is less confidence regarding flight restrictions at RIC
and whether or not the thicker cloud cover will make it to the
coast. Guidance now keeps MVFR/IFR west of RIC tonight. Did not
completely remove the MVFR from the TAF, but have trended it
toward less impact. Elsewhere, not expecting flight restrictions
within the TAF period outside of brief, shallow ground fog.
Winds look to remain light through the period and generally out
of the E.

There is a chc of showers late Mon evening into Tue, esply well
inland away from the coast. Minimal chcs of showers persist Tue
through Fri. Generally VFR/MVFR outside of any late night/early
morning fog/stratus.

&&

.MARINE...
As of 345 AM EDT Monday...

Key Messages:

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

- Persistent long period swells keep seas elevated throughout
this week.

-Northeast winds may become elevated next weekend.

A strong surface low pressure continues to linger far off the
eastern United States, with a strong high pressure (1022mb) over
north eastern Canada early this morning. As of 3:30 this morning
winds are gradually out of the east northeast around 10-15 kt with
occasional gusts in upwards of 20 kt. The winds today will stay
between 5-10 kts across the bay with occasional gusts up to 15 kt.
Across the ocean winds will be slightly higher with sustained winds
between 10-15 kt and occasional gusts in upwards of 20 kt. After
this afternoon winds will begin to diminish over all waters later
this evening. 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.

Throughout today waves across open waters will continue to build due
to the swell from the low pressure system far off the coast. Across
the bay waves are expected to be between 1-2ft(2-3 ft across the
lower bay and 3-4 ft across the mouth of the bay). The open ocean,
waves are expected to be between 4-6 ft throughout today and into late
this week. For now, have extended SCAs across the coastal waters
through Wednesday with future extensions likely. The SCA for the
mouth of the bay has been canceled at this time. However, model
guidance has suggested an extremely marginal SCA conditions later
Today. As of now confidence is too low to warrant an extension or an
additional SCA for this zone at this time. Model and real time
trends will continue to be monitored.

&&

.TIDES/COASTAL FLOODING...
As of 345 AM EDT Monday...

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 today are expected to be similar to Sunday. 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 continue to average +1.5 ft to +2.0 ft above
astro tide levels across the region. The high tides later today
into tonight look to reach levels similar to what occurred
Sunday aftn/evening. Again, the most widespread moderate
flooding (with local major flooding at a few places) will be
over the mid/upper Bay, including the tidal Potomac/Rappahannock
and the MD eastern shore through late this evening. These
locations still are expected to see additional 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 remain in effect 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, the high tide this
aftn/evening should be comparable to what occurred on Sunday, so
will maintain these Coastal Flood Warnings here through the late
aftn/evening timeframe. Have mentioned in the CFW the likelihood
at seeing additional flooding Tuesday (most likely minor
flooding).

Norfolk and Chesapeake remain in a Coastal Flood Advisory
through Tuesday (as opposed to a Coastal Flood Warning) given
that the Elizabeth River and Sewell`s Point should 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 this
afternoon.

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

- Lewisetta (P.O.R. since 1979): 13 (with several more to
  come), previous record was 8 in Oct 2021, Oct 2019, Oct 2015.

- Cambridge (P.O.R. since 1980): 7 (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 is unlikely to break records listed).

- Lewisetta (P.O.R. since 1979): 3 (so far), ***record is 7 in
  Oct 2015***

- Cambridge (P.O.R. since 1980): 1 (so far), ***record is 4 in
  Oct 2019***

In addition, a High rip current risk is in effect today and will
likely continue through at least Tuesday.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Warning until 2 AM EDT Wednesday for MDZ021>023.
     Coastal Flood Advisory until 4 PM EDT this afternoon for
     MDZ024-025.
NC...Coastal Flood Warning until 4 PM EDT this afternoon for NCZ102.
VA...Coastal Flood Warning until 4 PM EDT this afternoon 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 this evening for VAZ084-
     086-523>525.
     Coastal Flood Warning until 10 PM EDT this evening for VAZ089-
     090-093-096.
     Coastal Flood Advisory until 6 PM EDT Tuesday for VAZ095-097.
     Coastal Flood Warning until 8 PM EDT this evening for VAZ099-
     100.
MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ650-652-
     654-656-658.

&&

$$

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