613
FXUS62 KCHS 110941
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
541 AM EDT Fri Jul 11 2025

.SYNOPSIS...
Weak high pressure will extend across the area into early next
week. A surface front may sag into the area during the middle
of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Through This Evening: Mid-level heights will start to rise
today as subtropical ridging over the Atlantic begins to build
back to the west. Still expect another round of showers/tstms to
impact the area this afternoon and evening with more than
sufficient moisture and instability in place. Coverage looks to
be a bit less compared to Thursday where activity ended up
being fairly extensive. Activity could initially focus early/mid-
afternoon along the sharpening resultant sea breeze circulation
with additional airmass driven clusters forming farther inland.
This scenario is fairly typical for deep summer with convection
becoming locally enhanced near mesoscale boundary collisions.
11/01z NBM pops of 50-60% look reasonable and are in general
agreement with the latest HREF. Convection will gradually wane
through the evening hours before activity redevelops over the
coastal waters late where nocturnal convergence will strengthen
near the west wall of the Gulf Stream. It will remain seasonably
warm and humid with highs in the lower-mid 90s away from the
beaches. Heat indices will generally peak 101-106, highest
across the US-17 corridor in Charleston County where dewpoints
are poised to pool back into the upper 70s in the wake of the
sea breeze.

Severe Weather: 0-6km shear is forecast to remain fairly weak
(generally 10-15 kt) today, but with modified sounding showing
as much as 3000-4000 J/kg of MLCAPE during peak heating, several
pretty beefy storms are likely to occur a few of which could be
severe. Damaging winds from wet microbursts will be the primary
hazard along with a risk for frequent cloud-to-ground lightning.
Both WBZ and freezing levels will be a bit higher than Thursday
(14-15 kft), so large hail is not as much of a concern even
with HCAPE values near 1100 J/kg; however, some small hail
(possibly approaching 1"), could still occur in some of the
most intense updrafts.

Heavy Rainfall/Flooding: Storms should remain fairly progressive
this afternoon and evening. There will still be a risk for heavy
rainfall and at least minor flooding given PWATS are forecast to
remain in the 2.15-2.30" range. Intense hourly rainfall rates
are likely to occur with rates approaching, it not briefly
exceeding, 3 in/hr at times. The ground is still quite wet from
several days of rainfall and given these intense rainfall
rates, some flooding is likely to occur in spots, especially in
low-lying and poor drainage areas. More urbanized areas such
the Charleston and Savannah Metro areas area also at a slightly
higher risk. HREF 3-hr neighborhood probabilities for >1" of
rain are running 30-70% (highest Southeast Georgia) this
afternoon with >3" probabilities ~10% centered along the Georgia
coastal corridor where 850 hPa theat-e values are higher, storm
motions could be lower and there is better chance for outflow
interactions with the sea breeze. A few spots could see amounts
>4" per the HREF ensemble localized probability matched mean
(LPMM) output. Widespread flash flooding is still not expected
at this time despite the locally excessive rainfall observed
over parts of the area during the past 72 hours.

Overnight: Extensive debris cloudiness will gradually wane
through daybreak. Lows will range from the lower 70s inland to
the upper 70s/near 80 at the beaches and Downtown Charleston.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
An upper ridge will slowly build over the northern Gulf Coast
this weekend into early next week while Bermuda high pressure
remains in place off the East Coast. Temperatures will steadily
climb each day while deep southerly flow maintains dewpoints
well into the 70s. High temps by Monday could get close to 100F
across interior southeast GA. The max heat indices show a few
splotches of 108-110F within the coastal corridor Saturday and
Sunday, with a more widespread area of 108-113F on Monday. We
could need Heat Advisories for parts of the area. Rain chances
will be close to climo for mid-July with mainly diurnal
convection triggered by the sea breeze and convective outflows.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
The upper ridge will break down as we head into the middle of
next week. A weak surface trough or front could settle across
the inland half of the area, bringing an increase in shower and
thunderstorm coverage. Temps will be close to normal.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
11/12z TAF Discussion:
KCHS/KJZI/KSAV: The far southern flank of a region of IFR cigs
dropped into KSAV. Clouds have been somewhat variable there
between SCT-BKN005. These should lift shortly after daybreak, it
not before. For KCHS, an area of IFR cigs is near KRBW and could
get close to the terminal prior to daybreak. A TEMPO group for
IFR may be needed through about 13-14z depending on last minute
satellite trends. Otherwise. Another round of showers/tstms
could pose hazards at all three terminals this
afternoon/evening. Coverage does not look as great as what was
experienced Thursday. VCTS was maintained roughly 21-01z for all
terminals except at KCHS where a TEMPO was introduced 18-21z
for 4SM TSRA.

Extended Aviation Outlook: A typical summertime precipitation
pattern expected Saturday through Tuesday with mainly
afternoon/evening showers/tstms briefly restricting
ceilings/vsbys.

&&

.MARINE...
Today: Southerly wind regime will persist with high pressure
offshore. Typical sea breeze enhancements are likely along the
land/sea interface and Charleston Harbor with winds 15 kt with
gusts to 20 kt possible. Otherwise, winds will be 10-15 kt.
Overnight, a bit of a summer nocturnal surge is expected with
southwest winds nearing 15 kt with gusts as high as 20 kt. Seas
will average 2-4 ft through tonight.

Saturday through Tuesday: Persistent Atlantic high pressure
will maintain S to SW winds at or below 15 kt and seas at or
below 4 ft.

&&

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

&&

$$