501
FXUS62 KCHS 052238
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
638 PM EDT Sun May 5 2024

.SYNOPSIS...
Atlantic high pressure will remain across the Southeast U.S.
through much of next week. A cold front will move through the
region late week bringing cooler conditions heading into next
weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
This Evening: Few to scattered showers/thunderstorms will persist
for the next hour or two, initiated by a seabreeze circulation
shifting well inland, then drifting behind to the east-northeast
within a modestly unstable environment characterized by SBCAPE
around 1500-2000 J/kg and PWATs near 1.5 inches. A strong
thunderstorm with gusty winds and small hail can not be ruled out if
it initiates along or just west of the seabreeze well inland (mainly
southeast South Carolina near the I-95 corridor), where DCAPE values
around 500-800 J/kg reside. However, the window of opportunity
is rather small and activity will likely come to an end around
sunset as instability weakens with the loss of diurnal heating.

Overnight: Much like the previous night, conditions will become dry
for most areas while weak mid-lvl shortwave energy exits to the
north/northeast and a brief period of ridging resides across the
local area for much of the night. Patchy fog could develop across
some locations well inland late where skies are clear and winds
are light for much of the night, but coverage will likely
remain limited to locations that have experienced rainfall. At
this time, any mention of fog remains out of the forecast, but
could eventually be included. Lows will remain mild, ranging in
the mid 60s inland to upper 60s/lower 70s near the coast.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Larger scale ridging will be in place through the early part of the
week with surface high pressure off the coast stretching across the
Bermuda region. That said, convectively induced short-wave trough
(originating with convection moving through the lower/middle
Mississippi River Valley today) will advance through the Carolinas
and mid Atlantic region Monday afternoon into Monday night.
Temperatures warming into the 80s away from the coast and dewpoints
in the lower to middle 60s will yield a decent amount of instability
with MLCAPE values running 1000-1500 J/Kg Monday afternoon and
minimal convective inhibition. Modest forcing with the wave in
tandem with the inland pressing sea breeze should kick off scattered
to numerous showers and thunderstorms across the forecast area while
additional showers and storms develop through central Georgia into
the Midlands and potentially press into the region later in the day.
We will be maintaining 60 to 70 pops across inland areas Monday
afternoon with convection slowly diminishing Monday night...but
higher (categorical) pops may eventually be needed as convective
evolution becomes more clear in the near term. Severe weather threat
looks low overall although relatively slower moving storms and
healthy PWAT values could present a heavy rain threat.

Short-wave trough moves off the Atlantic coast Monday night followed
by low amplitude ridging building through the southeast CONUS for
Tuesday and Wednesday. Quieter conditions anticipated, although some
spottier shower/thunderstorms are possible across the Carolinas to
the mid Atlantic Tuesday and again Wednesday, although it`s tough to
pin down pops/timing at this juncture. We have maintained some lower
end precip chances across southeast South Carolina on Tuesday
followed by dry weather on Wednesday as mid level warming/capping
takes shape.

Otherwise, temperatures will continue to warm through midweek as
upper level ridging builds through the region and convective
coverage dwindles with highs in the middle to upper 80s Monday to
the lower 90s by Wednesday. Heat index values remain well below any
heat related headline criteria, but daytime high temperatures will
be pushing record high readings by Wednesday.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Unseasonably warm temperatures carry into Thursday with highs in the
lower and potentially middle 90s. Again, heat index values will
remain below headline criteria. But record high temperatures are a
good possibility again Thursday.

Otherwise, low amplitude upper level ridging will hold through the
beginning of the long term period before stronger short-wave energy
dives out of the Midwest and down through the mid Atlantic/southeast
CONUS late in the week into early part of the weekend. Associated
surface cold front will swing down into the region...slated to move
through the forecast area on Friday. This will be our next decent
chance for showers and thunderstorms...possibly as early as Thursday
afternoon from anything that gets going upstream, although the
higher precip chances come Friday with the boundary moving through.
Quieter and cooler (70s to 80s) weather settles in for next weekend
with possibly some showers lingering across the southern part of the
forecast area Saturday in the vicinity of the boundary.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
KJZI: Overnight, VFR conditions are forecast. There is a slight
chance of some patchy fog, but overall conditions don`t look to
conducive. The crossover temperature at KJZI is 68 degrees,
with low temperatures not forecast to get below that. Monday, a
leftover MCV will approach the terminals from the west. Current
TAFs aren`t advertising any mention of thunder, but this will
likely need to be added in future TAF issuances.

KCHS/ KSAV: Overnight, VFR conditions are forecast. There is a
slight chance of some patchy fog, but overall conditions don`t
look to conducive. The crossover temperature at KCHS/ KSAV is 66
degrees, with low temperatures not forecast to get below that.
Monday, a leftover MCV will approach the terminals from the
west. Current TAFs aren`t advertising any mention of thunder,
but this will likely need to be added in future TAF issuances.

Extended Aviation Outlook: Overall conditions will remain VFR
through the week although brief flight restrictions are possible at
the terminals Monday and to a lesser extent Tuesday.

&&

.MARINE...
Tonight: Marine conditions will remain quiet with high pressure
centered off the coast of New England favoring a south-southeast
wind around 10-15 kt locally this evening, followed by a gradual
weakening to around 10 kt or less as winds turn more directly
south overnight. Seas will generally range between 2-3 ft.

Monday through Friday: Atlantic high pressure will maintain
relatively benign conditions over the local marine waters.
Southeasterly winds in the morning will back slightly during the
afternoon and evening hours each day as the sea breeze develops.
Winds will average 10-15 kt with seas 2-4 ft. Winds will increase
toward the end of the week as a cold front approaches. Small Craft
Advisory conditions are possible as gusts approach 25 kt, but look
marginal at this juncture.

&&

.CLIMATE...
May 8:
KCHS: 93/1986

May 9:
KCHS: 95/1963
KSAV: 95/1962

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$

NEAR TERM...DPB
SHORT TERM...Adam
LONG TERM...Adam
AVIATION...Adam/Haines
MARINE...Adam/DPB