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000
FXUS61 KAKQ 150726
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
326 AM EDT Mon Apr 15 2024

.SYNOPSIS...
A cold front drops south through the area this afternoon and
evening with showers and thunderstorms possible for most of the
area. This front is forecast to lift back north as a warm front
Tuesday into Tuesday night. Another front crosses the area
Thursday with a stronger cold front then expected by the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 325 AM EDT Monday...

Key Messages:

1. Warm and dry through early this afternoon.

2. Strong to severe thunderstorms are expected to develop later this
afternoon, spreading southeast into this evening. Large hail and
damaging winds are the main threats.

Quiet wx this morning with high pressure centered well offshore of
the SE coast, though it ridges back W into the FL peninsula. Temps
are very mild for this time of night (in the mid 60s) with just
passing high clouds seen on nighttime satellite imagery. Remaining
similarly quiet after sunrise with mostly sunny skies and quickly
warming temps. Highs (before any convection arrives) will likely top
out in the mid-upper 80s for most of the area, with lower 80s on the
VA/MD Eastern Shore.

Attention then turns towards the severe wx threat this afternoon. A
southward-dropping frontal boundary with likely provide enough sfc
convergence to allow for the development of scattered thunderstorms
after about 2-4 PM. Trends with the latest CAMs have been to slow
the front by an hour or so (and thus storm initiation), so have
generally delayed PoPs across the board relative to the previous
forecast. The one aspect of this setup that is still uncommon for
this area are the steep mid-level lapse rates (7.5-8.5 C/km) that
are forecast to overspread the area today. These lapse rates can be
traced back to an elevated mixed later (EML) that was advected
eastward on the northern periphery of a mid-level ridge over the
Midwest states. This, combined with sfc temps well into the 80s and
dew points in the 50s, will allow for 1000-1500 J/kg of MLCAPE by
this aftn. Storm organization will also be fostered by
unidirectional WNW/NW flow aloft which leads to around 30 kt of bulk
shear. While the WSW sfc flow likely leads to some mixing and drying
during peak heating (and thus introduces some questions regarding
storm coverage), still expecting at least scattered tstm coverage
given the favorable low-level environment for cold pool propagation
and upscale growth. Coverage may be limited initially as there is
also a small cap shown in soundings that will need to be overcome.
In terms of the CAMs, most are in general agreement with the 3km NAM
being an outlier, showing slower frontal movement and lower storm
coverage overall.

The primary threats are large hail and damaging winds. Hail is
expected to favored initially as single cell or transient supercell
structures develop with the support of the aforementioned mid-level
lapse rates. Hail in the 1-1.75" range is most likely in any
discrete severe storm. As additional storms develop, upscale growth
into clusters and/or a line is expected as storms take advantage of
the favorable inverted-V low-level environment (DCAPE > 1000 J/kg
seen in model soundings). This will then favor the damaging wind
threat becoming dominant. Damaging wind gusts of 60-75 mph are
possible in any storm. The tornado threat remains very low. SPC has
a slight risk for most of the area with a marginal risk over the MD
Eastern Shore. Will continue to highlight this threat in the HWO.
The highest PoPs and storm coverage are initially expected N and NE
of metro Richmond, spreading S and SE into the US-460 corridor,
Middle Peninsula, and Hampton Roads. As heating is lost after
sunset, storm intensity and coverage will tend to decrease,
especially S of the NC/VA border. Expect all storms to dissipate by
12-2 AM tonight with just a lingering shower or two possible. Lows
tonight will range from the mid 50s N to around 60 S.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 325 AM EDT Monday...

The front moves back N as a warm front Tuesday into Tuesday
night as low pressure develops and moves NE out of the Plains
states. The coverage of showers and storms is expected to be
less Tuesday and mainly confined S and W of I-64 initially. The
storm threat is highly dependent on how much instability can
creep N, with the HRRR being the most aggressive with this. Will
have 20-30% PoPs with similar chances of thunder across our SW
counties. Highs Tue range from the upper 60s-low 70s E/NE to
mid/upper 70s-low 80s further W/SW. Low-end chances for a shower
or two continue into Tuesday night with lows in the 50s.

Mostly cloudy skies expected Wednesday with the front remaining near
the area. This could spark additional showers and isolated tstms,
especially N. Highs Wed in the upper 70s-low 80s for most of VA and
NC. It`ll remain around 70 on the Eastern Shore where the flow will
be off the cooler waters. A weak cold front approaches from the W
Wed night/early Thu which leads to a somewhat higher coverage of
showers. PoPs are 30-50% though QPF should remain on the light side
(0.25" or less). Overnight lows Wed in the 50s N/NE and 60s S.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 325 AM EDT Monday...

Remaining on the mild side heading into the extended period with on
and off unsettled periods. Thursday continues to look like the
warmest day of the extended period with highs in the 80s for most of
the area (70s across the NE), despite the weak cold front moving
through. Will keep chance PoPs through the day simply due to the
cold frontal passage occuring during the day. Will also have a low-
end thunder potential across the SE half of the area in the aftn.
Another (stronger) cold front moves toward the area later Friday
into Saturday with additional chances for showers and possibly
thunderstorms. The 00z suite of deterministic guidance is in
somewhat better agreement with the timing of the FROPA. The GFS and
ECMWF both show a Saturday FROPA, though the GFS is still several
hrs faster. Whether this occurs in the morning or aftn dictates the
extend of the tstm threat. There still isn`t much of a high QPF
signal as the front traverses E of the Appalachians so will keep
PoPs in the 30-40% range. Temps Friday will be seasonable with 70s
for most of the area and perhaps 60s on the ern shore. NBM guidance
suggests warmer temps on Saturday, though this is dependent on the
frontal passage and continue to see a large spread in the guidance
and ensembles. For now, expecting 70s and 80s (warmest S/SW). Sunday
will be the coolest day in the forecast period with temps topping
out in the 60s, though some guidance suggests 50s across the N.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
As of 145 AM EDT Monday...

VFR conditions to start the 06z/15 period. SW winds this evening
are averaging ~10 kt. With stronger winds aloft, the threat of
southwesterly LLWS continues for the next few hours. Otherwise,
FEW-SCT high clouds are noted at most terminals. Quiet on
Monday morning but a weakening cold front moves into the area by
afternoon. This is likely to trigger showers and storms by the
afternoon with strong wind gusts starting in RIC and SBY by
mid-late afternoon, then extending SE to PHF, ORF, and possibly ECG
by the evening. Heavy rainfall and isolated large hail are also
possible. There could be localized IFR- LIFR vsby restrictions
in the heaviest rain. Outside of storms, SW ~10 kt winds are
expected. Showers/storms should taper off by 6z Tue.

Outlook...There is a lower chance of showers/storms Tue
aftn/Tue night. Scattered to Isolated showers persist into Wed,
though not expecting flight restrictions.

&&

.MARINE...
As of 325 AM EDT Monday...

High pressure is off the SE CONUS coast early this morning. SW winds
have diminished to ~15 kt with gusts to 20 kt. Seas are 4-5 ft N and
~3 ft S. The wind will continue to slowly diminish this morning and
become WSW. With the diminishing winds, anticipate that the SCAs for
the Ches Bay, Lower James River, and ocean will be allowed to expire
at 4 AM.

A weakening cold front drops south this aftn/evening with the
potential for some stronger storms along and ahead of the boundary
(most likely timing is between 3-10 PM). At least a few SMWs will
likely be needed for 34+ kt winds and potentially isolated large
hail. Winds turn to the NE behind the front and then to the E-SE on
Tuesday (staying sub-SCA through this timeframe). Conditions will
generally remain sub-SCA for the rest of the week with some
potential for seas to build to ~5 ft in the northern coastal waters
by Thursday/Friday as another weak cold front crosses the
region.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 4 AM EDT early this morning for
     ANZ630>632-634-638-650-652-654.

&&

$$

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