-- Discussion containing changed information from previous version are highlighted. --
636
FXUS62 KCHS 061745
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
145 PM EDT Mon May 6 2024

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

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Midday update: Continuing to monitor trends. Latest SPC
mesoanalysis shows 1000-1500 J/Kg MLCAPE across the region and
minimal CINH. Spottier showers have developed, mainly across the
tri-county region, but a lack of any stronger focusing
mechanism. Convection may be becoming a bit more organized/focus
from eastern Georgia into the SC midlands ahead of the short-
wave trough. Recent HRRR runs have trended less bullish in
precip coverage across the region this afternoon and it may take
until some of the aforementioned convection to press in from
the west to get a bit better coverage. Continuing to monitor...

Previous discussion...
Morning composite analysis reveals short-wave ridging along the
southeast coast and surface high pressure off the Atlantic
coast. Pronounced short-wave trough extends from the Ohio Valley
down through Alabama with the parent circulation rolling
eastward through Tennessee and Kentucky. A few rounds of showers
and some thunderstorms are also moving through the Tennessee
Valley...extending into the South Carolina midlands. Across the
CWA, relatively quiet at the moment with a modestly juicy air
mass (dewpoints in the upper 60s to lower 70s) across the South
Carolina and southeast Georgia coastal areas.

Parent short-wave circulation will migrate toward the mid
Atlantic with modest troughing edging into the Carolinas/
northern Georgia region this afternoon into tonight. Modest
larger scale forcing for ascent in tandem with the developing
sea breeze circulation should kick of sct-nmrs showers and
thunderstorms this afternoon along with additional convection
developing in central/eastern Georgia and into the midlands
making a run toward the forecast area later in the day into the
evening. 60-70 pops were maintained for the afternoon with
decreasing chances along the coast

Strong-severe storm possibilities: Severe weather threat remains
on the low side. Locally heavier rain is possible with slower
moving convection. Diabatic heating will drive afternoon MLCAPE
values into the 1000-1500 J/Kg range, locally higher along the
sea breeze. But larger scale wind profiles will remain on the
very marginal side through peak heating with 0-6Km bulk shear
values climbing to around 20 knots while mid level lapse rates
remain generally under 6C/Km. That said, a briefly stronger
storm cannot be completely ruled out along a locally enhanced
instability max or slightly backed low level flow with the sea
breeze. Slightly stronger mid level flow will be spreading into
the region this evening, although past peak heating/instability.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Mid-level ridging will briefly set up over the region Tuesday into
Wednesday before becoming quasi-zonal Wednesday into Thursday. The
Southeast U.S. will still be positioned on the western grip of
Atlantic high pressure as a series of surface lows pass across the
northern CONUS. Lingering moisture from a recent passing shortwave
could result in the initiation of a stray isolated shower or
thunderstorm along the sea breeze Tuesday. The forecast currently
features POPs ranging 10-20% considering most locations will likely
stay dry. Conditions will remain dry through Thursday morning with a
mix of clouds and sun. The main focus during the short-term forecast
period is on temperatures, with a couple of unseasonably hot days
ahead. High temps will reach the upper 80s/low 90s Tuesday, rising
to the low 90s both Wednesday and Thursday, with some locations
reaching the mid 90s. Locations along the beach however will be
cooler, topping out in the mid 80s. Record setting high temperatures
are possible both days (see Climate section below). Dew points in
the upper 60s will keep heat indices from reaching the 100 degree
mark. Overnight, both Tuesday and Wednesday will be mild with min
temps in the upper 60s/low 70s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
A cold front will push across the area Friday bringing the next
chance for showers and thunderstorms. Guidance has trended the
timing of the front slightly quicker, and now shows the potential
for convection to spread in as early as Thursday evening and then
potentially another round Friday afternoon. In the wake of the
front, high pressure will build bringing dry conditions and cooler
temperatures through the weekend.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...

-- Changed Discussion --
VFR conditions persist at all terminals through Tuesday morning.

KCHS/KJZI: Scattered showers have developed in the tri-county
area and will be impacting mainly CHS over the next several
hours with a higher probability for thunder as well. Bulk of
convection will likely remain inland from JZI through the
afternoon.

At KSAV, a few showers are possible through the afternoon hours
with a better risk for showers/thunder late this afternoon into
this evening.

Precip coverage diminishes later this evening and overnight.
There could be some ground fog at the terminals toward morning,
although fog probabilities are too low to include in the
forecast for now.

Extended Aviation Outlook: Outside of a possible stray shower
Tuesday, VFR conditions are expected through the week.
-- End Changed Discussion --

&&

.MARINE...
At the sfc, the pattern will feature high pressure from the western
Atlantic to the northern Gulf of Mexico and a warm front across the
Ohio River Valley. This pattern should yield south-southwest winds
across the marine zones. Speeds are forecast to favor values between
10-15 kts today and tonight. Seas should range between 2-3 ft
through the near term period. Beyond 50 nm, seas may build to 4 ft
late tonight across the outer GA waters.

Tuesday through Saturday: 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
Thursday into Friday as a cold front approaches. Small Craft
Advisory conditions are possible as gusts approach 25 kt, but look
marginal at this juncture. By Saturday, winds will shift out of the
north around 10 kt with seas dropping to 3 ft or less.

&&

.TIDES/COASTAL FLOODING...
The upcoming New Moon (May 8) and recent Perigee (May 5) will lead
to high astronomical tides over the next few days. Minor coastal
flooding is possible along Charleston and coastal Colleton Counties,
including Downtown Charleston, during the evening high tides through
Thursday.

&&

.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...Adam/NED
SHORT TERM...BRM
LONG TERM...BRM
AVIATION...Adam/BRM/NED
MARINE...BRM/NED