046
FXUS61 KAKQ 201905
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
305 PM EDT Sat Jul 20 2024

.SYNOPSIS...
A weak front remains just north of the North Carolina-Virginia
border this afternoon, bringing unsettled conditions back to
most of the area with locally heavy rainfall likely. Unsettled
conditions are expected through much of next week with
scattered mainly afternoon and evening showers and thunderstorms
each day.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 300 PM EDT Saturday...

Key Messages:

- Areas of moderate to heavy rainfall continue through today. A
flood watch in effect for portions of central and southern Virginia.

- A few strong storms remains possible over southern Virginia and
northeast North Carolina this afternoon and evening.

A wavy stationary front has settled just N of the NC/VA border this
afternoon. There is also a weak sfc low along this boundary, which
should slowly translate eastward through today. Elsewhere, broad
high pressure is located offshore and over the OH Valley region.
Aloft, a subtle shortwave is sliding out of NC toward VA in about
~35 kt of 500 mb flow.

Latest radar shows widespread and slow-moving showers across most of
our CWA. PWATs are 2-2.2"+ from about the Northern Neck southward to
SE VA and NE NC. This, combined with slow storm motions and enhanced
sfc convergence, suggests a continued heavy rainfall and flash
flooding threat. Rates through most of this morning into this
afternoon have been very efficient, with MRMS estimates of 2-5"/hr
rates at times. A flood watch was raised with the morning update
earlier and continues through 10 PM for a good portion of our
VA counties. While there has generally been limited lightning
activity, sfc obs show temps surging into the mid 80s along and
S of the front (SE VA/NE NC) where satellite shows a good deal
of clearing. This suggests building sfc-based instability and
SPC mesoanalysis indicates at least 1000-1500 J/kg of MLCAPE
(SBCAPE even higher of 2000-3000 J/kg). Thinking is the best
thunder chances will be down in these regions and especially
during the next several hours. CAMs are in decent agreement that
the current activity will slowly move E into the areas of
higher instability, perhaps strengthening some as they do so.
Given the enhanced flow aloft (30-40 kt), effective shear
magnitudes are in the 30-35 kt range. SPC has a marginal risk of
svr wx across our srn tier of VA counties and over NE NC. The
primary threat is damaging wind gusts. Moist low-levels should
keep this threat on the isolated side. Additionally, a few
point-based model soundings show some low-level wind curvature
with localized sfc wind backing from the low. In fact, a few of
the showers today have displayed some weak low/mid-level
rotation and cannot rule out continued transient supercell
structures through this afternoon. While the tornado threat is
not zero, 0-1km SRH of only 50-100 m2/s2 and weak deep-layer
shear suggests this threat is very low.

Highs this aftn top out in the mid-upper 70s across the N and low-
mid 80s across the S. Partly to mostly cloudy skies prevail
overnight with lows in the upper 60s or lower 70s. Most of the
precip should be out of the area by midnight-2 AM. Depending on
where most of the falls tonight and if there is any clearing, some
patchy fog could develop, especially W of I-95 in the Piedmont.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
As of 300 PM EDT Saturday...

Key Messages...

- Lower coverage of showers and storms on Sunday as the front
meanders from central NC into VA in the afternoon.

- Higher coverage of storms and potential heavy rain/flooding
returns Monday.

The front remains near the area Sunday, but shower and storms are
expected to focus more across the S/SW. Fewer clouds and showers
across the northern half of the area will result in slightly higher
temps Sunday afternoon with highs ranging from the upper 80s N and
NW with mid 80s to the S. Some break in the humid conditions is
expected for the northern half of the area with dew points in the
upper 60s to low 70s while areas south of the I-64 corridor will
maintain dew points in the mid 70s and PWAT values greater than 2".
Similar the previous few days, any storm could produce heavy
rainfall and isolated flash flooding. However, the threat should be
more isolated than today and no flood watches are anticipated.
Overnight lows fall into the upper 60s to low 70s.

Not much change in the overall synoptic pattern on Monday with
continued SW flow aloft and deep moisture over the region. The front
is forecast to lift north of the area on Monday so there will be
less forcing in the low levels to focus shower and storm chances.
That said, diurnally driven convection is likely across the area
with locally heavy rainfall and flash flooding possible just about
anywhere in region. There was enough consensus in the global models
to increase PoPs to 70% for most of the FA. Highs Monday stay in the
mid to upper 80s with overnight lows again in the upper 60s to low
70s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 100 PM EDT Saturday...

Key Messages:

- Continued unsettled this coming week with deep moisture in
  place and daily chances for showers and thunderstorms.

The remainder of next week will see little change in the
overall pattern across the region with continued SW flow aloft.
Bermuda high offshore will maintain a feed of deep moisture into
the region with PWAT values generally aoa 2". Showers and
storms will generally follow a diurnal cycle, generally forming
over inland areas in the afternoon and spreading toward the
coast in the evening. Have maintained likely PoPs each afternoon
through Friday with somewhat lower chances on Saturday. There
are indications that this stagnant/wet pattern may take a break
by next weekend as sfc high pressure builds to our north and
pushes a cold front south of the area. Highs will be in the
mid-upr 80s to around 90 degrees Wednesday, then a few degrees
cooler for the latter half of the week with highs in the mid
80s. Overnight lows continue in the upper 60s to low 70s.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
As of 200 PM EDT Saturday...

Flying conditions continue to remain quite variable this
afternoon. SCT-BKN MVFR CIGs are noted at most sites, with the
exception of SBY. A frontal boundary will serve to trigger
additional showers and storms and localized flight restrictions
are likely in any convection. The highest coverage is expected
to set up in the I-64 corridor of SE VA, extending down into NE
NC this evening. Only isolated activity is expected up toward
SBY. Winds remain VRB through this afternoon (SE at SBY) at 5-10
kt. Rain/storms taper off tonight, with calm/light winds.
Cannot rule out some patchy fog overnight, depending on the
placement of today`s rainfall. Will not include any VSBY
restrictions in the TAFs at this time. CIGs again lower with the
highest confidence around SBY (MVFR likely w/ IFR possible).

Outlook: 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...Flood Watch until 10 PM EDT this evening for VAZ065>068-
     078>090-092-093-095>098-512>516-518-520-523>525.
MARINE...None.

&&

$$

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