774
FXUS61 KAKQ 200753
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
353 AM EDT Sat Jul 20 2024

.SYNOPSIS...
A weak front over NC will lift is lifting north early this
morning, bringing unsettled conditions back to most of the area
with locally heavy rainfall possible. Somewhat unsettled
conditions are expected through much of next week with scattered
mainly afternoon and evening showers and thunderstorms each
day.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 350 AM EDT Saturday...

Key messages:

- Weak frontal boundary lifts northward this morning with low
  pressure translating along the front this afternoon. Areas
  near and north of the boundary will see periods of moderate to
  locally heavy rainfall.

- A few strong storms are possible along and south of the front this
  afternoon and evening.

Early morning analysis shows high pressure well off the SE CONUS
with a weak front slowly making northward progress across NC and
into VA. Aloft, a broad positively-tilted trough is noted over
the Mississippi Valley into the Great Lakes, resulting in SW
flow over the region. Satellite imagery shows mostly cloudy
skies across the region and a few showers have developed along
the northward-advancing front near and just offshore from VA
Beach.

Expect the front to continue to lift north this morning with an
increasing chances for showers and a few storms. Skies will be
mostly cloudy today with widespread showers and storms possible
this afternoon into the evening. Temperatures will be held down
by cloud cover and showers with highs ranging from the upper 70s
NW to the mid 80s SE. A shortwave trough in the flow aloft will
result in weak low pressure forming along the frontal boundary
which will serve to enhance lift and low level convergence along
and north of the front this afternoon. CAM/HREF guidance shows
the greatest precip coverage and probabilities of 3"/3 hours
generally along the US 460 corridor today. WPC has included a
small Slight Risk area from the VA/NC border northward into the
I-64 corridor today. In coordination with neighboring offices,
have opted not to issue a flood watch for today with the highest
QPF placed just north of the areas that have received the most
rainfall over the last 72 hours (Mecklenburg County eastward
along the VA/NC border and into NE NC). If short term trends
show less northward progress with the front this morning, a
short-fused Flood Watch may be required for these areas. As low
pressure translates east along the front late this afternoon and
evening, PoPs will be focused across the SE third of the area
and near the coast/offshore after midnight. Enhanced flow aloft
will result in 25-30 kt of shear this afternoon and evening
along and south of the frontal boundary. Strong straight line
winds locally heavy rainfall are the main threats from
convection this afternoon and evening. SPC has areas near and
south of the VA/NC border in a Marginal Risk. Lows tonight range
from the mid/upper 60s N and NW to the low 70s SE.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 300 PM EDT Friday...

Key Messages...

- Unsettled on Saturday with locally heavy rain possible
  especially south of I-64.

- Warmer on Sunday with scattered showers/storms especially far
  southern VA and NE NC.

Latest CAMS are show a fairly good signal of locally heavy rainfall
in central or southern Virginia Saturday afternoon as the frontal
boundary hangs up over somewhere over southern VA or northern NC.
The area of heavy rainfall will be highly defendant on where
this front stalls out, but the consensus is that there will be
an area of heavy rain generally along US-460 tomorrow afternoon
as a weak low develops along the front helping to increase
moisture convergence along with precipitable water values
forecast at 2.2". At this time, will hold off on any flood watch
as the highest QPF is forecast to occur where lesser precip has
fallen the past few days. However, will need to monitor this
closely as a shift southward in the heavier precip would
possibly require a flood watch.

There is also a marginal risk for severe weather tomorrow afternoon
mainly southside and SE VA and NE NC. With the upper short wave
moving overhead, the mid level flow increases to 30-40 kt which
helps deep shear to increase to about 35 kt. There will likely be
some breaks in the clouds in the SE on Saturday as well with MLCAPE
values forecast to be around 1000 j/kg (although the breaks in the
clouds are uncertain). Although the mid level lapse rates will be
quite weak, there is a potential for bowing segments leading to
localized damaging wind gusts where there is some destabilization.

Highs tomorrow will end up below normal for much of the area due to
the excessive clouds. It will still be quite humid with dew points
in the 70s, but expect highs to the in the upper 70s/lower 80s north
and mid-upper 80s south.

After the frontal passage Sat night, the front will stall out once
again near or just south of the VA/NC border. Precipitable water
values drop to below 2" for at least the northern part of the
forecast area. Will therefore go with a dry forecast later Sat night
into Sunday morning for much of the area north of the VA/NC border.
Will need to keep chance PoPs south due to the proximity of the
front. Sunday afternoon, expect scattered showers and storms to
develop with the best concentration in NC. Highs on Sunday rise back
into the mid-upper 80s.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 300 PM EDT Friday...

Key Messages:

- Somewhat unsettled through the week with mainly afternoon and
evening showers/thunderstorms.

- Daytime temperatures near normal, but it will be rather humid
through the week.

With the Bermuda high anchored offshore and SW flow aloft for much
of the week, we will not see much change in the weather next week.
Showers and storms will be favored mainly in the afternoon and
evening hours with convection developing inland then moving toward
the coast by evening. Precipitable water values stay around 2" all
week, with surface dew points in the low to mid 70s. This will allow
for the potential for heavy rainfall at any time or place in the
forecast area, but there is no way to pin down any specifics at this
point. As such, will mostly go with likely PoPs each afternoon Mon-
Wed with chance PoPs Thu and Friday. It is interesting that the NBM
24 hour QPF probabilities show a 10-20% probability of over an
inch of rain throughout the week, but then only a 50-70%
probability of 0.01". This implies that there is the potential
for heavy rainfall at any given time, but also suggests that it
could stay dry.

Daytime temperatures are expected to stay near normal in the upper
80s to around 90 all well. However, with the deep moisture and high
dew points, lows will struggle to drop below the lower 70s all week.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
As of 755 PM EDT Friday...

A cold front has pushed S into NC as of 00z. VFR with SCT-BKN
mid and high clouds and any showers over s-central VA into
interior NE NC are dissipating. The wind is mainly E to SE at
5-10kt. The boundary will slowly lift back N as a warm front
late tonight into Saturday. As the boundary lifts back into the
region early Saturday morning MVFR cigs are likely at RIC, ORF,
PHF, and ECG, with IFR cigs possible at RIC. MVFR cigs are
expected to linger at these sites into early aftn. Showers
arrive from the SW early Saturday morning and gradually spread
SW to NE through the day, with tstms possible in the aftn. Any
showers/tstms will contain heavy rain that could produce brief
IFR/LIFR vsby. The wind will mainly be light out of the E to SE
tonight, then E to SE 5-10kt Saturday, shifting to SW in the
aftn at ECG as the front lifts N.

MVFR/IFR cigs are possible in vicinity of the boundary Saturday
night. Unsettled conditions continue Sunday through Wednesday
with daily chances of mainly aftn/evening showers/tstms.

&&

.MARINE...
As of 250 AM EDT Saturday...

Key Messages:

- A warm front lifts north through the area today, bringing light
and variable winds.

- Prevailing sub-advisory conditions are expected to continue
through at least early next week, although afternoon/evening
thunderstorms are possible each day.

A warm front is slowly moving north across nrn NC early this
morning, with E-SE winds of 5-10 kt over the waters and 2-3 ft
seas/1-2 ft waves. The front is progged to continue to lift north
across part of the area today before stalling as weak sfc low
pressure tracks along it. The weak low moves offshore tonight. Winds
will generally be E-SE at ~10 kt today, with S-SE winds south of the
front (over the far SE VA/NE NC coastal waters). Winds become
variable this evening as the low tracks over the waters before
turning to the W-NW tonight (and remaining well below SCA
thresholds). Despite the prevailing sub-SCA conditions, scattered to
numerous tstms could produce locally higher gusts (especially from
midday through this evening). Light and variable winds are expected
Sunday with continuing shower/storm chances. S/SW winds become more
established Monday and especially the middle of next week as the
pressure gradient tightens between Bermuda high pressure offshore
and weak low pressure well to our NW. It still looks to remain
predominantly sub-SCA through the period, outside of brief higher
wind gusts from convection. Waves in the bay average 1-2 ft while
seas average 2-3 ft. Seas increase to 3-4 ft across the northern
waters mid-late this week as SSW winds become a bit more elevated
(but still below SCA thresholds).

Will continue with a moderate rip current risk across the northern
beaches this weekend, with a low rip risk for VA Beach/Eastern
Currituck.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.

&&

$$

SYNOPSIS...RHR/MRD
NEAR TERM...RHR
SHORT TERM...MRD
LONG TERM...MRD
AVIATION...AJZ
MARINE...ERI/SW