-- Discussion containing changed information from previous version are highlighted. --
158
FXUS61 KAKQ 230801
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
401 AM EDT Thu May 23 2024

.SYNOPSIS...
A cold front approaches from the northwest today bringing
scattered afternoon and evening showers and thunderstorms. The
boundary weakens and pushes south Friday with less coverage of
afternoon and evening showers and thunderstorms. The front lifts
back north Saturday with daily chances of afternoon and evening
showers and thunderstorms continuing through the Memorial Day
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 335 AM EDT Thursday...

Key message:

- Strong to severe thunderstorms are possible this afternoon and
  evening.

An upper ridge axis is centered in vicinity of the Mid-
Atlantic coast early this morning with surface high pressure
centered off the Southeast coast. Mostly clear and mild early
this morning with temperatures in the mid 60s to lower 70s,
along with a 5-10 mph SSW wind. Meanwhile, an upper trough is
digging across the Great Lakes with a cold front trailing into
the Ohio Valley. This trough and cold front will push E today
providing a trigger for afternoon and evening showers/tstms.
00z/23 HREF depicts some enhancement in the 500mb flow by this
afternoon associated with a shortwave trough resulting in deep
layer shear on the order of 30- 40kt, along with mean surface-
based CAPE of 1000-1500 J/kg. Strong surface heating is expected
out ahead of the front with 850mb temperatures of ~16C
supporting highs in the mid 80s to around 90F, with even lower
to mid 80s at the coast. The combination of strong surface
heating, deep layer shear, and modest instability will bring a
potential for line segments capable of producing strong to
damaging wind gusts, with large hail possible from stronger
updrafts. SPC has maintained a marginal risk across the Mid-
Atlantic for the Day 1 outlook, with timing generally 3-10PM.
One question that remains is what effect an ongoing MCS over
the lower Mississippi Valley will have on downstream convection
later today. In other words, does outflow from this system
trigger convection in the Southeast that limits the northward
transport of richer moisture into the Mid-Atlantic.

Showers/tstms diminish in coverage later this evening into the
early overnight hours tonight. Partly to mostly cloudy with low
temperatures in the mid to upper 60s.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
As of 335 AM EDT Thursday...

Key Messages:

- Summerlike with less coverage of showers and thunderstorms
  Friday.

- Continued summerlike Saturday with the potential for more
  coverage of afternoon and evening showers and thunderstorms.

The initial boundary settles into the Carolinas by Friday with
shortwave ridging building across the Mid-Atlantic. Therefore,
coverage of showers/tstms should be less Friday with PoPs
ranging from at or below 15% NE to 30-40% S and SW (which may be
generous). Remaining summer-like and rather hot Friday with
highs in the mid to upper 80s inland, and upper 70s to lower 80s
at the coast due to a developing sea-breeze in weak flow. Mild
Friday night with lows in the 60s. There is not much of a
trigger for showers (or evening tstms), but a ~20% PoP will be
maintained in a warm and rather humid airmass. 23/00z guidance
has some broad consistency in showing shortwave energy arriving
Saturday in westerly mid/upper level flow, with the boundary
lifting back to the N, but confidence in the details remains
low. Given this, PoPs for mainly afternoon/evening showers/tstms
are 30-40% across the entire area. Highs Saturday will once
again be in the mid to upper 80s, with upper 70s to lower 80s
toward the coast.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 335 AM EDT Thursday...

Key Message:

- Remaining warm and humid Sunday into Memorial Day with the
  potential for showers and thunderstorms Memorial Day.

Continued warm and humid Saturday night with any showers/tstms
diminishing in coverage as shortwave ridging arrives in the
westerly flow aloft. Lows will mainly be in the 60s. Highs
Sunday will once again be in the mid to upper 80s inland with
upper 70s to lower 80s toward the coast. Less coverage of
showers/tstms are expected Sunday afternoon/evening as broad
ridging prevails, with PoPs less than 15% NE to ~30% SW. 23/00z
EPS/GEFS depict an anomalous trough digging from the Great
Lakes to the Northeast Monday through Wednesday with a cold
front pushing through the Mid- Atlantic. Confidence on timing
remains on the low-side, but given the strength of the trough
more coverage of showers/tstms are possible in the Memorial
Day/Monday night timeframe. Highs Memorial Day will once again
be rather hot in the mid 80s to around 90F (slightly lower at
the coast), with highs trending down into the upper 70s to lower
80s toward the middle of next week with drier air also arriving
into the region.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
As of 155 AM EDT Thursday...

High pressure is centered off the Southeast coast as of 06z. VFR
under a mostly clear sky with a light SSW wind of 5-10kt. A cold
front approaches from the W today bringing a chc of
showers/tstms, primarily during the mid-late aftn and evening
timeframe. Primarily VFR through this evening, with the
exception of brief flight restrictions (mainly vsby) in
showers/tstms. The wind will be SW 8-12kt today outside of
tstms, with locally strong to severe wind gusts possible from
tstms. There is still enough uncertainty in timing, so VCTS
wording has been maintained.

The front stalls in the vicinity of the region Friday-Monday,
bringing daily chances for mainly afternoon/evening
showers/tstms. Chances for showers/tstms are mainly 15-20% NE to
30-40% SW Friday, 30-40% across the area Saturday, and 15% or
less NE to 20-30% SW Sunday. There is the potential for more
coverage of showers/tstms Monday as an upper trough approaches
from the NW.

&&

.MARINE...
-- Changed Discussion --
As of 355 AM EDT Thursday...

Key Messages:

- Benign conditions expected on the waters through the Holiday
weekend.

- Shower and storm chances are expected for this afternoon and
  evening and are possible again over the holiday weekend.

Early this morning, sfc high pressure was centered well off the
Mid Atlc coast, while a cold front was approaching the area from
the NW. Winds were SSW 5-15 kt with a few gusts up to 20 kt
across the waters. Waves were 1-2 ft and seas were 2-3 ft.

Shower and storm chances will increase this aftn into this
evening, with the front`s approach. But the front will be
weakening as it arrives and stall across the region. It will
then waffle back and forth across the area through the Holiday
weekend. While this will keep the chances for showers and tstms
in the forecast through the weekend into early next week, the
winds and seas will remain below sca levels through the period.
Overall expect wind speeds 5-15 kt, with seas 2-3 ft and waves
1-2 ft.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...AJZ
AVIATION...AJZ
MARINE...ESS/TMG