635
FXUS62 KCHS 052005
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
405 PM EDT Fri Jul 5 2024

.SYNOPSIS...
A weak cold front approaching from the west will stall inland
this weekend and linger through the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Late this afternoon, KCLX detected a line of weak returns associated
with a sea breeze drifting just inland of the coastal counties.
Inland of the sea breeze this afternoon and early evening,
temperatures should remain in the mid to upper 90s with dewpoints at
least in the mid 70s. The combination of the hot temperatures and
warm dewpoints will result in widespread heat index values between
105 and 110 degrees. A Heat Advisory will remain in effect for most
of the inland counties until 8 PM this evening.

A mid-level ridge will remain across the forecast area this evening
and tonight. Late this afternoon, visible satellite indicated
generally fair weather cumulus across the forecast area. However,
two areas of towering cumulus was noted near Lake Moultrie and
across the Altamaha River Basin. The forecast will feature SCHC to
CHC PoPs for showers and thunderstorms across extreme SE GA.
Elsewhere, it appears that an isolated shower or two is possible,
but the life cycle would likely remain less than 20 mins.

Conditions should steadily stabilize after sunset, resulting in
convection to dissipate by late evening. The rest of the night
should remain dry with light south winds. Low temperatures are
forecast to favor values in the mid to upper 70s.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
The upper ridge will be centered over northern Florida on
Saturday while a weak shortwave rotates around the northern
periphery during the afternoon. A weak cold front is forecast to
drop southeast into the area during the day, then stall nearby
through early next week. A corridor of extremely high PWATs
(2.25-2.5 in, near/above the 99% percentile) is expected to
roughly be oriented along and inland of I-95 in the afternoon,
between the surface front to the west and the 700 mb ridge axis
oriented roughly along the beaches to the east. Weak mid-level
subsidence inversion will help convective initiation to hold off
until midday to early afternoon, allowing temps to warm into the
mid-90s away from the immediate coast. This, in combination with
dew points in the mid 70s, will bring heat index values once
again to 105-110 degrees away from the beaches, and a Heat
Advisory will be needed for tomorrow afternoon.

By early afternoon, low level moisture convergence and inland
troughing will allow for the initiation of convection along and
inland of the sea breeze. Weak flow aloft will bring storm
motions only around 10 mph or less, which, combined with the
aforementioned elevated PWAT values and CAPE values near 2500
J/kg will bring the potential for a few strong storms inland
with locally heavy rainfall (amounts up to 3+ inches) and wet
microbursts producing gusty winds the primary concerns into the
evening. Convective activity diminishes and shifts inland
through the evening Saturday.

Sunday and Monday will continue to bring an unsettled pattern as
the weak front remains inland and weak disturbances aloft bring
periods of enhanced storm chances. POPs generally follow a
diurnal pattern, with widespread coverage inland both
afternoons, and relatively quieter conditions overnight.
Weakening of the upper ridge decreases the threat for dangerous
heat, but sufficient instability and moisture remain in place
for there to still be at least a limited threat for stronger
storms or locally heavy rainfall mainly along and west of I-95
each afternoon.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A fairly wet pattern likely to persist for much of next week due
to deep tropical moisture in place, continual shortwaves, and
inland/Piedmont troughing and weak moisture convergence
near/east of the weak cold front well inland. The greatest
coverage should be during the afternoon and evening hours.
Weaker ridging aloft and uncertainty surrounding precip timing
and coverage makes the dangerous heat threat more uncertain next
week. Additionally, there are no clear signals of any specific
day having an elevated severe weather threat, but at least a few
stronger storms and some localized heavy rainfall is possible
each day through at least mid-week as is normal this time of
year.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Prior to the 18Z TAFs: Visible satellite and sfc observations
indicated that a sea breeze was just inland of KJZI, approaching
KCHS and KSAV. The sea breeze is expected to pass over KCHS and
KSAV during the mid-afternoon hours, shifting winds from the
south. Terminals should remain VFR and convection free through
tonight. On Saturday, conditions should become unstable early
in the day as a front approaches from the west. KSAV TAF will
feature a mention of VCSH by 17Z.

Extended Aviation Outlook: Brief flight restrictions are possible in
showers and thunderstorms, mainly in the afternoon and evenings,
this weekend through the middle of next week.

&&

.MARINE...
Tonight: The sfc pattern will support south winds between 10 to 15
kts. Seas will favor values around 3 ft, with 2 ft see common within
5 km of shore.

Saturday through Wednesday, a typical summertime pattern will
persist, with prevailing moderate southerly flow, gusty winds
developing near the coast in the afternoon and persisting into
the evening/overnight hours, and only modest medium period SE
swell keeping seas mainly 2-3 ft. In summary, winds/seas
expected to remain below advisory thresholds.

Rip Currents: A swell of 2 feet every 9 to 10 seconds and proximity
to the new moon will maintain a Moderate Risk for rip currents for
Saturday.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory until 8 PM EDT this evening for GAZ087-088-099-
     100-114-115.
SC...Heat Advisory until 8 PM EDT this evening for SCZ040-042>045-
     052.
MARINE...None.

&&

$$

NEAR TERM...NED
SHORT TERM...CEB/JRL
LONG TERM...CEB/JRL
AVIATION...CEB/JRL/NED
MARINE...CEB/JRL/NED