-- Discussion containing changed information from previous version are highlighted. --
844
FXUS62 KCHS 250748
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
348 AM EDT Sat May 25 2024

.SYNOPSIS...
-- Changed Discussion --
A weak disturbance will move through the area this evening.
Hot conditions expected for Sunday and Memorial Day. A cold
front could bring impacts to the region Monday night into
Tuesday.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Today through This Evening: A zonal flow aloft across the
Southeast U.S. will steadily translate into a slight ridging
pattern as surface high pressure maintains its influence on the
region. Several subtle mid-level perturbations are progged to
cross the area later this afternoon and evening as heights
slowly rise. Mostly dry conditions will continue this morning,
although a warm/moist environment could support a brief shower
just about anywhere through mid-morning. It will be another hot
day for Southeast South Carolina and Southeast Georgia with
1000-850 hPa thicknesses progged to rise about 20 m and 850a
about 0.5-1C. This should translate to highs similar to Friday`s
readings with most areas expected to peak within a degree or
two of 90.

Attention shifts the convective potential this afternoon and
evening as strong shortwave energy approaches from the west.
Dewpoints are progged to mix out into the mid-upper 60s before
pooling back into the lower 70s at the coast this afternoon as a
typical resultant sea breeze circulation begins to meander
inland. Despite low-level moisture mixing out a bit, modified
soundings support MLCAPE 1800-2500 J/kg, highest at the coast
where low-level moisture will pool in the vicinity of the sea
breeze. Convection could spark by early-mid afternoon along
parts of the resultant sea breeze with upper Charleston County
favored for initiation--a typical behavior with the formation of
the resultant. Outflow boundaries generated by this activity
could initiate convection a bit farther down the sea breeze and
over parts of the Charleston Tri-County as the afternoon
progresses. Other isolated showers/tstms could form along the
resultant along coastal Georgia by late afternoon.

Late this afternoon and into this evening, the strongest of the
mid-level perturbations will approach from the west and push
offshore by mid evening. There are signals in the CAMs that a
cluster of tstms could initiate over central GA by late
afternoon and propagate into Southeast Georgia this evening.
Although thermodynamics ahead of this activity looks favorable
for the development of deep convection as low-level dewpoints
begin to recover as sunset approaches and a ribbon of higher
850 hPa theta-e works in from the west, 0-6km bulk shear looks
to only average about 20 kt or so. This activity will likely
remain fairly pulsy as a result with elevated DCAPE values of
1000-1300 J/kg juxtaposed with steep low-level lapse rates of
7-8 C/km supporting an isolated damaging wind threat. If enough
of a cold pool develops or mesoscale boundary interactions
occur, then a more loosely organized convective cluster could
pose a slightly higher chance for damaging winds over Southeast
Georgia could materialize. Confidence on how this scenario will
unfold is low as much will depend on how the mesoscale environment
evolves as the day progresses. Per earlier coordination with
the Storm Prediction Center (SPC), a marginal risk was
reintroduced to the day 1 WFO convective outlook guidance,
mainly for damaging winds. A tertiary area of convection could
approach the Santee-Cooper lakes region by late evening as yet
more convection works east/southeast out of the Midlands. This
activity should be in a weakening state as it moves into the
Charleston Tri-County with the onset of boundary layer cooling.

Overnight: A mostly dry night will prevail once evening convection
dies off and the mid-level impulses propagates offshore. It
will remain warm and fairly humid with lows ranging from the
upper 60s well inland to the mid 70s at the beaches. There is a
chance that little fog could develop early Sunday morning,
especially where rain falls today. However, the fog could remain
fairly light with no significant impacts.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
-- Changed Discussion --
Ridging builds overhead on Sunday which will aid in limiting
convection. Rain chances are no higher than 20%. Main story
will be the unseasonably hot temperatures. Highs peak in the low
to mid 90s across most locations. Lows Sunday night only fall
to the low/mid 70s.

Mid level ridge axis shifts offshore on Monday/Memorial Day as a
broad trough moves into the eastern U.S. At the surface, a cold
front will approach the region from the west. Little convection is
expected through at least mid-afternoon then upstream showers and
thunderstorms could move into the area later in the day into the
evening. There is potential that this activity is more
organized and pose a risk for stronger storms with gusty winds.
Highest rain chances shift offshore late Monday night/early
Tuesday morning. Lows will mainly be in the upper 60s to lower
70s.

The front should push offshore on Tuesday. Deepest moisture also
exits the area, and the weather looks fairly quiet with just
isolated showers/thunderstorms are still possible. High
temperatures again above seasonal normals in the lower 90s.
-- End Changed Discussion --

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
-- Changed Discussion --
High pressure builds into the region for late week behind a
secondary cold front that passes through later Wednesday night
or early Thursday. Rain-free forecast in tact, essentially
disregarding the outlier/wetter GFS. Temperatures should return
back to more seasonable levels.
-- End Changed Discussion --

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
25/06z TAF Discussion:
KCHS/KJZI/KSAV: VFR will prevail. There could be a little ground
fog that develops prior to daybreak, but this is not expected to
be significant at any of the terminals. Isolated to perhaps
scattered showers/tstms will develop over the area this
afternoon/evening. Confidence in the timing/placement of
convection remains fairly low this far out with the lack of any
meaningful forcing mechanism. There could be slightly higher
chance at impacts at KCHS/KJZI during the mid-afternoon as
isolated convection pops near the sea breeze, then KSAV late
afternoon/early this evening as there are signals that a more
concentrated area of showers/tstms could make a run for that
terminal as it moves out of central Georgia. Given the low
confidence on these scenarios, no mention of TSRA will be
included for the 06z TAF cycle. The need for TSRA will be
reevaluated for the 12z TAF cycle.

Extended Aviation Outlook: Brief flight restrictions are
possible due to showers/thunderstorms each afternoon/evening.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
Through Tonight: A southerly flow regime will prevail through
tonight. Winds will remain less than 15 kt with seas 1-2 ft. A
cluster of tstms could move off the Georgia coast later this
evening which could produce convective winds >34 kt.

Sunday through Thursday: South to southwest winds persist through
early next week. A cold front will then pass through the waters
before high pressure builds for late week. Conditions stay below
Small Craft Advisory through the period. Winds speeds average 15
knots or less with seas 2-3 feet on average.
-- End Changed Discussion --

&&

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

&&

$$