842
FXUS61 KAKQ 211341
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
941 AM EDT Sat Sep 21 2024

.SYNOPSIS...
High pressure looks to linger across the Southeast with a series of
shortwaves passing through our area ahead of a developing area of
low pressure. Off and on rain chances will persist through the
forecast period. Cooler temperatures are expected to start next
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 940 AM EDT Saturday...

Key Messages:

- Pleasant weather for most of the day 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.

High pressure remains centered well to the N ridging down the
East Coast this morning and low pressure is still lingering
well offshore to the NE. Aloft, a trough axis is located
offshore, and a broad ridge is situated to the west which places
the local area under NW flow. Some low clouds linger over far SE
VA with a slowly dissipating band of mid clouds over central VA.
Otherwise, mostly sunny with temperatures rising through the
upper 60s and lower 70s, after early morning lows in the upper
50s to lower 60s.

Today should be pleasant as precip will hold off until the late
afternoon hours. A shortwave traveling down the ridge will trigger
showers and perhaps a few rumbles of thunder late today. CAMs are in
pretty good agreement regarding timing and coverage of precip. May
see a shower or two enter the far NW counties in the second half of
the afternoon, but majority of precip should move in after sunset.
Scattered showers/storms then gradually cross the area overnight.
Will note that SPC has included far western portions of the area in
a MGNL for today. There will be decent shear in the area, as the 00z
HREF shows ~30-35kt of effective shear. However, the window for
severe weather will be limited given the narrow timeframe for
sufficient CAPE. If severe storms do form, the threats would be
damaging wind gusts and hail. Highs today will be in the low 80s for
most, and the mid-upper 70s immediately near the coast. Lows tonight
will be in the mid-60s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 345 AM 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

A weak backdoor cold front is forecast to cross into the local area
early Sunday morning and lingers in the area through the day. The
CAMs have come into good agreement that isolated/widely scattered
showers will accompany the front, so have put in slight chance PoPs
in the NE Sun morning, progressing SW through the day. Temps will
depend on the location of the front through the day, but can expect
low-mid 70s in the NE and temps around 80 in the SW. Much of the
area will also be under cloudy skies as well. Lows Sun night will be
in the upper 50s to low 60s.

The ridge axis aloft shifts over toward the E coast on Monday.
Meanwhile, sfc low pressure offshore finally makes some progress on
its journey S. Mon looks pleasant for the FA, 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.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 345 AM EDT Saturday...

Key Messages:

- Multiple low-end chances for precip Tues-Fri.

An area of high pressure looks to be traversing the far southeast
coast on Tuesday before sliding just offshore midweek. An initial
shortwave will cross the middle Mississippi River valley on Tuesday
before ejecting into the Great Lakes ahead of a developing cut-off
low further west. Here locally, we will be in southwesterly flow in
between the high pressure and low pressure, allowing moisture to
continue to slide in around the edge of the ridge. Rain chances will
try to nudge back in on Tuesday, but may get held up to the western
side of the CWA depending on the position of the high. Beyond that,
00z models still disagree on the position of the broad area of low
pressure, thus confidence in the forecast for midweek and after is
low. Generally, would expect low-end rain chances to persist for
now. 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.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
As of 655 AM EDT Saturday...

VFR will prevail for to start the 12z TAF period. Vsbys are
already improving at the terminals. Seeing some MVFR CIGs at
ORF, but not expecting this to last more than a few hours this
morning. Expecting dry weather for most of the day. Scattered
showers move in from the NW during the late afternoon hours.
Have introduced VCSH to the RIC and SBY TAFs. While the SE
terminals may see showers by the end of the 12z period, not as
confident in precip coverage in the SE, so left it out of the
TAF for now. May start to see some flight restrictions in the
form of MVFR CIGs toward the end of the period. Light southerly
winds expected at RIC today. NE winds at the coast gradually
become E/SE this evening.

Outlook: Lower CIGs (mostly MVFR) will be likely in most areas
Sun into Sun evening, due to more moist NE or E flow. Isolated
showers will be possible also.

&&

.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 Sunday night for
     MDZ021>023.
     Coastal Flood Advisory until 4 PM EDT Sunday for MDZ024-025.
NC...Coastal Flood Warning until 4 PM EDT this afternoon for NCZ102.
     Coastal Flood Watch from Sunday morning through Sunday
     afternoon for NCZ102.
VA...Coastal Flood Warning until midnight EDT Sunday night for
     VAZ075-077.
     Coastal Flood Warning until 4 PM EDT this afternoon for VAZ098.
     Coastal Flood Watch from Sunday morning through Sunday
     afternoon for VAZ098.
     Coastal Flood Warning until 8 PM EDT Sunday for VAZ076-078-085-
     099-100-521-522.
     Coastal Flood Advisory until 6 PM EDT this evening for VAZ083-
     084-086-089-090-093-095>097-518-520-523>525.
     Coastal Flood Watch from Sunday morning through Sunday
     afternoon for VAZ084-086-523>525.
     Coastal Flood Watch from Sunday morning through Sunday evening
     for VAZ089-090-093-095>097.
MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ650-652-654-
     656-658.

&&

$$

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