499
FXUS62 KCHS 121053
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
653 AM EDT Wed Jun 12 2024

.SYNOPSIS...
A stationary front will meander near or just off the coast
through the end of the week. High pressure will build in from
the north through the weekend, then shift east early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The forecast area will remain under slight mid-level ridging through
today. At the sfc, SE GA/SC should remain on the edge of weak high
pressure centered over KY. A wavy front positioned from the northern
Gulf of Mexico, across middle FL, and NE over the western Atlantic
will remain nearly stationary today. This pattern should support
steady ENE winds across the forecast area this morning. By this
afternoon, temperatures are expected to range from the low 90s
across the inland counties to the upper to mid 80s along the coast.
A sea breeze should develop early this afternoon, pushing inland
through the mid to late afternoon. Forecast soundings show a strong
inversion centered at H7, with dry air aloft. The forecast area
should remain dry today.

It is interesting to note that some of the near term guidance
indicates that a compact and deepening frontal wave will develop off
the FL/GA coast over the Gulf Stream this afternoon. These guidance
members then track the system to the NE along the front, spreading a
plume of deep moisture west over the SC coast late tonight. However,
nearly all guidance indicates that a broadening inverted trough will
remain along the front. Given that a longwave H5 trough over the
Deep South will slide east tonight, a solution indicating a weak
spot low seems reasonable. Taking this compromise approach, the
forecast will feature SCHC PopS approaching the SC coast late
tonight. Low temperatures are forecast to range from the upper 60s
inland to the low 70s along the coast.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
Thursday and Friday: An area of broad surface high pressure to our
northeast will slide offshore Thursday as an upper trough, largely
limited to the Mid-Atlantic, pushes a cold front toward the area
from the northwest Friday night. A weak trough will develop along a
stationary front positioned just off our coast Thursday, becoming
slightly more defined by Friday. This will result in a fairly decent
moisture gradient across the area with a relatively dry air mass
well inland and a plume of deep moisture streaming northeast across
the Florida Peninsula and into the Atlantic. Showers and
thunderstorms will largely be limited to the coastal waters in
proximity to the boundary and weak trough/low, but there could be
enough moisture and instability to generate, at the most, isolated
convection along the coast both days. The general thinking is that
areas far inland will remain mostly rain-free, with coastal
southeast Georgia being the prime location for potential convection
initiation (where the greatest moisture is located). Any convection
that does develop should diminish in the evening. Highs in the upper
80s to low 90s Thursday will increase to the mid 90s Friday. Lows
will range from the upper 60s far inland to the lower 70s near the
coast, and mid 70s along the beaches Thursday night. Friday night
will warm slightly into the low to mid 70s.

Saturday: As the weakening cold front pushes across the area
Saturday, the coastal low will push further out into the Atlantic.
Weak flow aloft will become replaced by a building ridge from the
southwest. As a result, Saturday features rain-free conditions with
mostly clear skies as subsidence over the area strengthens. A steady
increase in temperatures will continue owing to the upper ridge. We
could see highs reach the upper 90s most places, with the beaches
staying a bit "cooler" in the low 90s. Although approaching
dangerous levels, heat indices will stay shy of Heat Advisory
criteria; ranging between 100-105 degrees.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
A deep layered ridge across the Southeastern U.S. will prevail
through early next week. Surface high pressure will set up across
the Northeast, resulting in return flow helping to wrap the deeper
Gulf moisture around the backside of the high and into the Deep
South. The advection of moisture/instability will support scattered
showers and thunderstorms early next week, mainly during the
afternoon and evening hours when the sea breeze is active.
Temperatures should begin to slightly decrease and trend toward near
normal or slightly above normal.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
The terminals are forecast to remain VFR through the 12Z TAF
period. A sea breeze is timed to advance across KJZI by 17Z and
KCHS and KSAV during the mid to late afternoon. A period of
gusty ESE winds should occur in the wake of the sea breeze this
afternoon. East winds are forecast to settle between 5 to 10 kts
around sunset.

Extended Aviation Outlook: Mostly VFR conditions expected; however,
isolated convection could bring brief flight restrictions mainly in
the afternoon on Thursday and Sunday.

&&

.MARINE...
Today and tonight: The marine zones will remain between weak high
pressure centered over KY and a wavy stationary front over the
western Atlantic. This pattern should provide the region with steady
ENE winds, generally between 10 to 15 kts. Seas should remain
between 2 to 3 ft. An area of low pressure may develop along the
stationary front over the Gulf Stream tonight. Isolated showers and
thunderstorms may develop over the coastal waters late tonight.
Otherwise, winds will remain from the ENE between 10 to 15 kts with
seas between 2 to 3 ft. Late tonight, 4 ft seas may develop across
portions of the other GA and Charleston County waters.

Thursday through Monday: Thursday will feature a coastal trough/weak
low along or near coastal Georgia. Broad high pressure to the north
with the weak area of low pressure to the south will result in winds
out of the northeast around 10-15 kt. Low pressure could become
better defined by Friday before quickly moving out into the
Atlantic. Winds will then shift out the south Saturday before
settling out of the east Sunday as northerly high pressure returns.
Wind speeds will average 10 kt or less over the weekend/early next
week with seas 2 to 4 feet.

&&

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

&&

$$

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