776
FXUS62 KCHS 130743
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
343 AM EDT Sat Jul 13 2024

.SYNOPSIS...
A weak front will meander across the area today. Atlantic high
pressure will then rebuild across the area while a surface
trough exists inland Sunday through the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Through Sunrise: Convergence is slowly building along the
Charleston County coast early this morning. Near term guidance
suggests convection could pop across parts of Charleston and
Berkeley Counties prior to daybreak then shift offshore after
sunrise. These storms will likely be slow moving and capable of
producing some torrential rainfall with minor flooding of low-
lying and poor drainage areas a possibility.

Today: Weak low pressure will meander across Southeast Georgia
today as as subtle trough extends north across the eastern
portions of the Carolinas today. The surface trough will remain
a focus for showers/tstms again today with the bulk of
convection expected to remain displaced across northeast South
Carolina into eastern North Carolina closer to a ribbon of
channeled mid-level vorticity lurking just offshore. Mean
moisture values look a tad lower compared to Friday with both
PWATs and 850 hPa theat-e expected to trend lower. Despite
this, plentiful mixed-layered instability and some convergence
in the vicinity of trough axis should be enough to support
scattered showers/tstms across the coastal counties with more
isolated convection farther inland where surface dewpoints will
run quite a bit lower. Pops will range from 20% across the
interior to 30-40% at the coast, highest in the Beaufort-Charleston
Metro corridor where a relative 850 hPa theta-e axis maximum is
noted. The primary hazards with any tstms today will be gusty
winds, locally heavy rainfall capable of producing minor
flooding of low-lying/poor drainage areas and frequent cloud-to-
ground lightning.

Highs today will range from the mid-upper 90s west of I-95 to
the mid-upper 80s at the beaches. Dewpoints are expected to mix
out into the mid-upper 60s across far interior Southeast Georgia
this afternoon, but still look to hold in the mid-upper 70s
east of I-95 to the coast. Maximum heat indices look to peak in
the 105-108 range along/east of I-95. A few spots along the
Georgia and far southern South Carolina coastal counties could
exceed 108, but any such instances look to remain somewhat
limited. A Heat Advisory will not be issued for this reason.

Tonight: Convection will quickly wane this evening with the loss
of insolation. Expect a mostly dry night with continued warm and
humid conditions. Lows will range from the mid 70s well inland
to the lower 80s at the beaches and Downtown Charleston.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
Weak ridging aloft will persist across the local forecast area
as a mid-level trough swings across the eastern CONUS. At the
surface a weak, stalled front will persist just inland of the
local forecast area. Shortwave energy will ripple across the
southern periphery of the mid-level troughing, likely remaining
to the north of the local forecast area. PWATs are forecast to
be around or just over 2 inches. Weak forcing from the nearby
front as well as local enhancements from the sea-breeze
circulation will create scattered to numerous showers and
thunderstorms each afternoon. MLCAPE values are forecast to be
upwards of 2,000 J/kg each afternoon, however will little to no
shear the threat for organized severe thunderstorms is low.
However, a strong to marginally severe thunderstorm cannot be
ruled out.

The main forecast highlight for the short term period is the
increasing heat. Hot and humid conditions are forecast each day,
with Heat Indices reaching to around 105-110 Sunday through
Tuesday. Heat Advisories will likely be required for portions of
the forecast area, mainly along and east of I-95.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Ridging aloft will begin to retreat as a mid-level trough
swings towards the East Coast late in the week. At the surface
high pressure will briefly build into the region, with a cold
front approaching late week. At least scattered showers and
thunderstorms will be possible each afternoon, typical of a
summerlike pattern. Outside of precipitation, hot and humid
conditions are expected again on Wednesday. Another Heat
Advisory will be possible on Wednesday. Temperatures and dew
points begin to decrease Thursday and into Friday as a cold
front approaches.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
13/06z TAF Discussion:
KCHS/KJZI: VFR for much of the period. Near term guidance
suggests an uptick in convection could occur near KCHS just
before daybreak, likely holding just north of the that terminal.
VCTS was highlighted 09-13z to account for this. Activity should
stay far enough north of KJZI that no mention is needed at this
time. Another round of scattered showers/tstms will develop
across the lower South Carolina coastal corridor this afternoon.
VCTS was noted at both KCHS and KJZI from roughly19-23z to
cover this. Confidence for direct impacts this far out is not
high enough to justify any prevailing or TEMPO conditions. This
will be reevaluated for the 12z TAF cycle.

KSAV: VFR for much of the period. Isolated to low end scattered
shower/tstms could develop along the Georgia coast mid-late
afternoon. Activity looks a bit more sparse compared to areas
just to the north, so no mention of VCTS or TSRA will be
included for the 06z TAF cycle. The need for this will be
reevaluated for the 12 TAF cycle.

Extended Aviation Outlook: Scattered afternoon showers/tstorms
could produce brief flight restrictions at all terminals through
next week.

&&

.MARINE...
Through Tonight: Southerly winds will persist with speeds less
than 15 kt and seas 2-4 ft. Locally heavy rainfall will
accompany and showers/tstms with vsbys 1 NM or less at times.

Sunday through Wednesday: A pinched gradient could develop over
the marine waters through early next week as high pressure
persists offshore and a trough lingers inland. However,
conditions are expected to remain below Small Craft Advisory
criteria. Generally S winds are forecast, 10-15 knots. Slightly
stronger wind speeds are possible along the direct coastline in
association with the afternoon sea breeze. Seas should average 3
to 4 ft.

Rip Currents: A moderate risk for rip currents is in place for
the Charleston County beaches today where winds will be a bit
higher compared to the rest of the coast from Edisto Beach
south. 2-3 ft swells with periods of 7-8 seconds will persist.

Waterspouts: Non-supercell tornado parameters are rather
elevated along the lower South Carolina coast this morning
within a region of increasing speed convergence. While there is
no indication of a land breeze circulation setting up, lines of
towering cumulus and showers could yield a few waterspouts this
morning, mainly between the South Santee River to Tybee Island.

&&

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

&&

$$