-- Discussion containing changed information from previous version are highlighted. --
907
FXUS61 KAKQ 172002
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
402 PM EDT Tue Sep 17 2024

.SYNOPSIS...
Low pressure will slowly lift west to northwest along the
border of South Carolina and North Carolina this afternoon. The
system will continue to gradually weaken through Wednesday. Rain
showers expected through tonight, with the pattern remaining
unsettled Wednesday and Thursday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 300 PM EDT Tuesday...

Key Messages:

- Rain chances continue into this evening from south to north, rain
may be locally heavy at times and lead to instances of flash
flooding.

- A Flood Watch remains in effect for much of the area along and
east of I-95 (excluding the Maryland and Virginia Eastern Shore)
this afternoon.

Latest surface analysis shows a 1024mb high pressure just off
the coast of New England. Sfc low pressure that was previously
associated with PTC8 continues to drift WNW along the North and
South Carolina and Georgia boarder before moving back to the NE
later this evening. Recent satellite and radar imagery shows
multiple bands of showers and thunderstorms across North
Carolina and off the coast of Virginia. The first band of
showers and thunderstorms that brought rain into far eastern
North Carolina and the Tidewater area has slowly moved off
shore. These showers brought 1-2" localized 2.5" inches of rain
across Tidewater and 1-3" localized 4" inches across
northeastern North Carolina as of 2PM. This band is now bringing
light to moderate rain showers across the southern tip of the
Lower Eastern Shore. The second batch of showers and
thunderstorms are now initiating along a boundary that is
localed across North Carolina. This second boundary is expected
to slowly propagate northward and move an additional round of
showers and possible thunderstorms into northeastern North
Carolina and southeastern Virginia later this afternoon and into
this evening. The environment that these showers will be moving
into will be optimal for additional heavy rainfall. In far
south eastern Virginia instability has slowly been building in
with MLCAPE values ranging between 500-1000 J/kg. PWAT values
have continued to stay between 2-2.5 inches. Aloft, weak to
moderate 950mb and 850mb winds continue to fetch moisture on
shore and across the area into this evening. Will note, CAMs
have not been able to handle the the convection well. Real time
observations will continue to be monitored. At this time the
flood watch will stay in effect until later this evening. Real
time weather conditions will continue to be monitored to see if
the flood watch can be taken down or extended.

Later on this evening the showers and thunderstorms will continue to
taper off. Winds across northeastern North carolina and southeastern
Virginia will become calm this evening. With calm winds and an
abundance of residual moisture patch fog is expected across that
region tonight and into the mid morning hours of tomorrow.
Visibility could drop  to 1-2SM with isolated heavier patches of fog
that could potentially drop visibility to less than 1SM. Visibility
should improve by the late to mid morning hours tomorrow.
Temperatures for tonight will remain mild as clouds prevent
temperatures to cool down. Lows are forecasted to be in the middle
to upper 60s inland and lower 70s along the coast.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 300 PM EDT Tuesday...

Key Messages:

- Continued unsettled conditions Wednesday into Thursday with an
upper low lingering near the region.

- A backdoor cold front drops southeast across the local area on
Friday.

No big changes within the short term forecast. Shower chances
will continue both Wednesday and Thursday. However, Pops will
decrease during these days. An upper low gradually stalls south
of the area on Wednesday and gradually drift off to the
northeast on Thursday. With this system lingering Pops will
remain in the forecast. Wednesday the showers will be more
isolated to scattered in nature than widespread (best potential
across the western half of the area). With on shore continuing
for the week expect widespread cloud cover to continue to keep
temperatures cool (especially across the northwest) with highs
expected to range from the lower 70s NW to the lower 80s SE.
Cool and cloudy conditions continue on Thursday with decreasing
cloud cover late. Highs on Thursday will generally be in the mid
to upper 70s. A weak backdoor cold front will push SE across
the region during the day Friday, which will bring a slight
chance for an afternoon shower. Highs on Friday will range from
the upper 70s to around 80.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 PM EDT Tuesday...

Key Messages:

- Drier, cooler weather arrives this weekend into early next week.

Aloft, a tall upper level ridge builds well into Canada and
Greenland with an upper level trough along the East Coast this
weekend into early next week. At the surface, low pressure lingers
off the Mid Atlantic coastline through the weekend, gradually
shifting south Sun into early next week. Meanwhile, high pressure
remains centered in Quebec through Sat before dropping south into
New England by Mon. As the high pressure builds south, it will push
a backdoor cold front across the area Sat with cooler, drier weather
expected this weekend (especially Sun) into early next week.
However, given the low off the coast, coastal areas can expect
breezy conditions with gusts to 25-30 mph this weekend into Mon
along with greater cloud cover and humidity. Additionally, cannot
rule out a few isolated showers along the coast (15-25% PoPs).

Highs range from the mid-upper 70s to around 80F (across the
piedmont) Sat, mid 70s Sun and Mon, and mid-upper 70s Tue. Lows
range from the upper 50s (Piedmont) to mid 60s (coast) Fri night,
mid-upper 50s (Piedmont) to low-mid 60s (coast) Sat night, mid 50s
(Piedmont) to lower 60s (coast) Sun and Mon nights, and upper 50s
(Piedmont) to mid 60s (coast) Tue night.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
As of 155 PM EDT Tuesday...

Low pressure lingers over the southern Appalachians this
afternoon with widespread light to moderate rain across the
area and MVFR/IFR CIGs. Expect the heaviest rain to remain
generally near the coast (east of I-95) through this afternoon
with VIS occasionally dropping to IFR (1-2 SM). Rain continues
through tonight but should decrease in intensity. Additionally,
models are now hinting at the potential for fog across southern
VA and northeast NC late tonight into Wed morning with IFR VIS
possible (due to a combination of fog and drizzle). CIGs will
likely continue to bounce around from IFR to MVFR through this
afternoon before crashing to IFR/LIFR this evening across all
area terminals. CIGs continue to lower through the night with
200-500 ft CIGs possible across the terminals late tonight into
Wed morning. VIS improves by mid morning Wed, however, IFR CIGs
likely persist through the afternoon at RIC/PHF/ORF (lower
confidence at SBY). ECG likely improves to MVFR CIGs by Wed
afternoon. IFR CIGs will again be possible Wed night (MVFR at
SBY). E/ENE winds remain 10-15 kt with gusts 20-25 kt (highest
along the coast) this afternoon. Winds diminish to 5-10 kt
overnight (potentially below 5 kt across southern VA and
northeast NC). Winds become NE 5-10 kt Wed.

Outlook: Unsettled weather continues Wednesday through Friday,
but the degree to which this leads to flight restrictions is
uncertain.

&&

.MARINE...
-- Changed Discussion --
As of 400 PM EDT Tuesday...

Key Messages:

- Small Craft Advisories remain in effect for the Chesapeake Bay
  and lower James River area this evening.

- Small Craft Advisories linger into tomorrow for the coastal
  waters due to elevated seas.

- Another round of Small Craft Advisory conditions appears
  increasingly likely this weekend into early next week.

Latest sfc analysis shows an area of 1024+ mb high pressure to
centered to the north over New England. To the SW, the weakening
remnants of PTC 8 continues to meander over the Carolinas. The
tight pressure gradient between these features has allowed for
elevated winds and waves to continue this afternoon. Latest obs
reflect easterly winds of 15-20kt with a few gusts into the
20-25 kt range, mainly in the lower bay and lower James River.
Seas are slowly subsiding as well, but are still up around
6-7ft, with waves 3-5ft, highest in the lower bay.

The sfc low will continue to meander to our SW through tonight,
allowing the pressure gradient to slowly relax and winds to
gradually improve from S to N through the night. Winds should
decrease further late this evening and overnight, as a weak
area of secondary low pressure passes over the coast overnight.
Winds diminish to 10-15kt overnight, which will continue
through Wednesday. Seas should also improve through Wed, but
the onshore wind and E-NE swell (8-10 second) will make this
improvement gradual. SCA has been allowed to drop over the
sound and upper rivers, and will extend into late this evening
over the Bay and lower James River. Seas will linger in the 4-6
ft range over southern waters through tonight then slowly
subside from south to north through the day tomorrow. We`ve made
only minor adjustments to SCAs there accordingly.

The coastal low then exits to the NE as high pressure builds in
from the NW. Winds veer around to the N/NW for Thu-Fri at
~10kt, and it appears that we should get a couple of days of
sub- SCA conditions in to the end work week. Seas will be
3-4ft, waves 1-2ft. However, conditions become unsettled once
again with another protracted round of SCAs appear increasingly
likely over the weekend due to the re-tightening of the sfc
pressure gradient between high pressure pushing in from the NNE
and low pressure retrograding south just offshore. This will
result in re-building NNE winds over the weekend, with seas
quickly building to 5-8 ft, driven largely by renewed E-NE
swell.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
As of 400 PM EDT Tuesday...

Astronomical tides will continue to increase through this
evening with the approach of the next full moon. Higher astro
tides along with prolonged onshore flow will lead to nuisance to
low- end minor tidal flooding across much of the area along the
bay and tidal rivers tonight. Have issued a round of CF
Advisories for the upcoming high tide cycle tonight for much of
the bay, VA eastern shore, and adjacent tributaries. Tide
levels have so far remained below flood thresholds on the
eastern shore, but with the upcoming astronomically higher tide
cycle and given the slight upward trend, have issued a CF
statement over the bay side of the lower MD eastern shore.

Additional advisories/extension of Advisories will likely be
needed through the end of the week and into the weekend due to
extended periods of onshore flow and high astro tides. So far,
moderate flooding is not expected through Friday. However, a
building flood tide Saturday into Saturday night does bring the
potential for tide levels reaching moderate Coastal Flood
Thresholds (best chances northern coastal zones and lower bay)
for tide cycles over the upcoming weekend.
-- End Changed Discussion --

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
MD...None.
NC...Flood Watch until 7 PM EDT this evening for NCZ012>017-030>032-
     102.
VA...Flood Watch until 1 AM EDT Wednesday for VAZ064-075>078-
     080>090-092-093-095>098-511>525.
     Coastal Flood Advisory until 4 AM EDT Wednesday for VAZ075-077.
     Coastal Flood Advisory until 6 AM EDT Wednesday for VAZ076-078-
     085-522.
     Coastal Flood Advisory until midnight EDT tonight for VAZ084-
     086-089-090-093-095>100-523>525.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ630-
     631.
     Small Craft Advisory until 4 AM EDT Wednesday for ANZ632-634.
     Small Craft Advisory until 1 AM EDT Wednesday for ANZ638.
     Small Craft Advisory until 6 AM EDT Thursday for ANZ650.
     Small Craft Advisory until 1 AM EDT Thursday for ANZ652-654.
     Small Craft Advisory until 1 PM EDT Wednesday for ANZ656-658.
-- End Changed Discussion --

&&

$$

SYNOPSIS...HET
NEAR TERM...HET
SHORT TERM...AJB/HET
LONG TERM...RMM
AVIATION...RMM
MARINE...AM/MAM
TIDES/COASTAL FLOODING...