329
FXUS61 KAKQ 051951
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
351 PM EDT Wed Jun 5 2024

.SYNOPSIS...
Unsettled weather continues through Thursday. Additional
scattered, hit or miss style, showers and storms continue late
today and tonight. A cold front pushes across the region late
Thursday into Thursday evening, with a few strong to severe
storms possible. Behind the front, cooler, drier conditions push
into the region for Friday and Saturday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 305 PM EDT Wednesday...

Key Message:

- Scattered showers and thunderstorms are expected late this
  afternoon and this evening. A few stronger storms are
  possible, but locally heavy rainfall remains the main threat
  from any of today`s storms.

- Remaining mostly cloudy, warm and muggy tonight, with a few
  lingering showers overnight.

Latest analysis ~1020mb high pressure off the mid-Atlantic
coast. To the NW, deepening ~988 mb sfc low pressure was
analyzed over the Canadian Prairies, with a weak quasi-
stationary boundary extending SSE across the upper Great Lakes
and along/just S of the Mason-Dixon line to the upper eastern
shore. Aloft, a dampening upper level ridge has built over the
eastern seaboard, with quasi-zonal mid-level low over the
region. The first in a series of shortwave troughs/MCVs has
pushed offshore of the eastern VA coast. The second, centered
over the VA piedmont, will cross (mainly) north of the region
from SW to NW through this evening, with the third, extending
from the eastern OH River Valley into the mid-South, crosses
the region this evening into the early overnight hours
(~00-06z).

19z temperatures vary from upper 70s to low 80s across the
northern and central CWA, with mid to upper 80s over SE VA into
NE NC.

CAMs are generally struggling with convective signal, mainly a
result of the weak forcing today. Scattered showers and storms
continue to develop over the next few hours. Given PW in the
1.6-1.8" range, locally heavy rainfall is the main hazard,
especially as better deep- layer shear values look to remain
along and just north of our area over to the eastern shore (a
Marginal Risk from SPC remains across our far northern tier of
counties). That said, it does appear possible that a few
stronger storms will also be possible along a differential
heating boundary that could very well develop this aftn across
far SE VA into NE NC. PoPs remain in the 20-40% range over much
of the area, ticking up into likely range across the northern
neck Richmond/Westmoreland counties (VA) over to the MD eastern
shore. Given the multiple perturbations crossing the region and
the moist antecedent airmass, areal coverage (ISO-SCT wording)
remains the best fit for the forecast late today and tonight,
with showers and storms of the pulsy, loosely organized
convection of the hit- or-miss variety the expected storm mode.

The greatest coverage and intensity of convection slides over
the SErn counties this evening. While CAMs have largely
misdiagnosed the setup to a decent degree, modest instability,
a small uptick in lapse rates and the crossing shortwave all
point to this area seeing a few more showers and storms (20-40%
coverage), with an isolated stronger storm or two possible over
southside Hampton Roads and NE NC in the respective wet microbursts.

The last shortwave crosses the area this evening, with at least
a few additional isolated to widely scattered showers expected
to persist into the late night hours. Rain chances taper late as
the wave weakens and exits. Some spotty low stratus and fog is
likely, and added mention of patchy fog overnight over the MD
eastern shore and northern neck. Lows late tonight in the upper
60s to low 70s under a partly to mostly cloudy sky.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
As of 300 PM EDT Wednesday...

Key Messages:

- Remaining warm and muggy Thursday.

- Early morning showers and storms followed by more numerous
  showers and storms Thursday afternoon and evening preceding a
  crossing cold front.

- A few strong to severe storms are possible over the region.
  Locally heavy rain, gusty winds, and frequent lightning are
  the expected hazards in any storms Thursday afternoon into
  Thursday evening.

Low pressure trundles slowly east toward E Ontario/James Bay
region tomorrow, with its surface cold front crossing into the
eastern Great Lakes and eastern OH/TN River valleys by sunrise
Thu morning. The front then slowly slides east toward the area
through the day on Thursday.

The WPC Excessive Rainfall Outlook remains in place for
portions of the area Thursday, with PW values remaining near
climo daily maxes (~1.7-1.8"). More showers and storms look
redevelop along the pre-frontal trough by late Thu morning into
early afternoon, as the cold front swings east of the central
Appalachians. The pre-frontal environment over the local Aurea
is expected to be characterized as marginally unstable, with
MLCAPE on the order of 1000-1500 J/kg along with a modest
increase to deep layer bulk shear of 25-30 kt (W-SW) and mid-
level lapse rates ~6-6.5 (C/km). The modest uptick in 3-8 km
shear could easily help to focus developing convection a little
bit more as the front drops through the region, allowing for a
marginal strong to severe/quasi-linear storm mode to be favored.
The best chance for a few strong to severe storms Thu aftn is
along and E-SE of I-95 into eastern VA and NE NC, but a few
damaging wind reports are possible area wide. SPC has upgraded
to a Marginal Risk across the entire region for Day 2. Again,
gusty winds are the main storm threat, but locally heavy
rainfall/urban flood issues are also a concern. Finally, given
the quasi-zonal flow aloft and rather moist low-level airmass,
any storms that fire will likely also be rather prolific
lightning producers as well. Timing for storms looks to be
18-21z west (2-5 PM EDT) in the west and 20-02z (4-10PM EDT)
east of I-95.

Highs in the mid to upper 80s Wed (highest SE) and upper 80s to
lower 90s Thu expected.

Showers and storms taper off from W to E Thu evening, with
drier air filtering into the region late Thu night into Fri
morning.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 300 PM EDT Wednesday...

Key Messages:

- Drier weather returns Friday through Sunday, with mainly dry
  weather to persist into early next week.

- Near to below normal temperatures appear likely over the
  weekend into early next week, trending back to and above
  normal for the latter half of the week.

Drier weather moves in Fri behind the departing cold front as
dewpoints drop into the 50s. Pleasantly cooler and drier Friday
night into Saturday, with dry weather expected. Aloft, an upper
level low moves into the Great Lakes on Fri, lingering into
early next week. Guidance is coming into better agreement with
pushing the next weakening front though the region on Sunday
night, but it still appears the upper level low is too close to
the local area for enough instability for much in the way of
widespread showers and/or storms on Sunday. Instead, only a
slight chance for a few isolated showers/storms exists late Sun,
with slight to low- end chance PoPs continuing along the coast
into Monday. Highs mainly in the lower to middle 80s with lows
in the upper 50s to 60s.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
As of 330 AM EDT Wednesday...

VFR conditions across much of the area, with localized MVFR in
scattered showers and storms at 18z, mainly over northern
terminals and over the eastern shore (around the KSBY terminal
and north of KRIC). Showers will continue to increase in
coverage through this afternoon, with CIGs/VSBY to remain mainly
VFR. We should see a break in showers later this evening with
another round of scattered showers possible overnight, as one
last mid-level disturbance crosses the area. Some patchy low
stratus and fog is possible late tonight, mainly across the
eastern shore and N of KRIC. KSBY has the best chance of any
VSBY restrictions late tonight, and have carried a brief period
of MVFR CIGs after 08-09z tonight.

Outlook: Additional scattered showers/tstms are expected once
again Thursday late morning and into the afternoon as a cold
front approaches from the west. A few strong storms are
possible, with some gusty outflows that could gust to 30-40 kt.
Mainly dry Friday through Sunday behind the font, with VFR
likely prevailing for much of Friday through Sunday.

&&

.MARINE...
As of 300 PM EDT Wednesday...

Key Messages:

- Small Craft Advisories have been issued for all local waters
except the upper tidal rivers.

- Chances for showers/storms could cause locally higher winds and
waves this evening and again on and Thursday afternoon and evening.

-Low rip current risk late this afternoon, with a moderate risk for
the northern beaches Thursday and Friday.

High pressure has moved well offshore ahead of an approaching trough
and cold front over the Midwest. Flow aloft is rather weak across
the local area with an upper trough moving into the western Great
Lakes and a building ridge over the SW CONUS. Winds locally are from
the S or SW 5-10 kt with waves/seas generally 1-3 ft.

Expect the pressure gradient to tighten this evening and tonight as
the cold front continues to approach the region from the NW. Winds
increase to 15-20 kt with gust to 25 kt over the Ches Bay, lower
James River, and Currituck Sound late this evening. Offshore, winds
will be more marginal but there will be a period with gusts near or
slightly higher than 25 kt. Confidence in seeing these winds is
highest for the waters near and north of Cape Charles Light but
opted to include all the coastal waters in SCA headlines to better
match with neighboring offices. Winds diminish quickly Thursday
morning but have extended the SCA headlines in the Ches Bay for a
few more hours than previously forecast. Offshore, winds will also
fall off quickly but there is some potential for 4-5 ft seas to
linger into the afternoon hours for the waters north of
Chincoteague. Will let subsequent shifts fine-tune the timing if
necessary. The surface cold front moves through the waters late
Thursday into the overnight with sub-SCA conditions prevailing late
week and into next weekend.

&&

.TIDES/COASTAL FLOODING...
As of 300 PM EDT Wednesday...

Some nuisance to minor coastal flooding is forecast this evening and
tonight. Minor flooding is forecast for bay-facing portions of the
MD Eastern Shore including Cambridge, Bishops Head, and Crisfield
where a Coastal Flood Advisory has been issued. Nuisance flooding is
possible along the tidal Potomac and Rappahannock Rivers tonight as
well and a Coastal Flood Statement has been issued for this region.
Otherwise, most tidal sites in the middle and lower bay, including
up the James River, may see only very shallow flooding near the
waterfront over the next couple days.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Advisory from 10 PM this evening to 7 AM EDT
     Thursday for MDZ021>023.
NC...None.
VA...None.
MARINE...Small Craft Advisory from 10 PM this evening to 1 PM EDT
     Thursday for ANZ630>632-634.
     Small Craft Advisory from 1 AM to 10 AM EDT Thursday for
     ANZ633-638.
     Small Craft Advisory from 1 AM to 1 PM EDT Thursday for ANZ650-
     652-654.
     Small Craft Advisory from 10 PM this evening to 10 AM EDT
     Thursday for ANZ656-658.

&&

$$

SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...MAM
LONG TERM...MAM
AVIATION...MAM
MARINE...RHR
TIDES/COASTAL FLOODING...