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593
FXUS62 KCHS 200519
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
119 AM EDT Thu Jun 20 2024

.SYNOPSIS...
High pressure will extend across the region into Thursday. A
tropical wave will impact the Southeast U.S coast Thursday
night into Friday. High pressure will return over the weekend.

&&

.NEAR TERM /THROUGH 6 AM THURSDAY/...
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The forecast area will remain between a sfc ridge across the
central Carolinas and a wave of low pressure to the northeast
of the Bahamas. A region of moisture convergence will persist
along the coast through most of the night, especially the
Georgia coastal counties. Isolated to scattered showers will
develop in waves as a result. Low temperatures are forecast to
range from the mid and upper 60s inland to the lower and middle
70s along the coast.
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&&

.SHORT TERM /6 AM THURSDAY THROUGH SATURDAY/...
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A ridge of high pressure will continue to hold influence over
the local area on Thursday. Meanwhile, a trough of low pressure
will shift westward towards the Southeast coast. While a few
showers can`t be ruled out primarily at the coast, similar to
previous days, forecast soundings indicate dry air and strong
subsidence which will act to limit shower activity. Highs will
mainly be in the upper 80s to lower 90s. Lows will range from
the mid 60s across the interior to mid 70s at the immediate
coast.

The aforementioned trough will likely shift onshore somewhere
near the GA/FL border early Friday. PWats will steadily
increase, forecast to exceed 2 inches by Friday, and showers are
expected to shift onshore through the day. While there should
be a fair amount of coverage, no rainfall/flooding concerns are
anticipated. Highs will again be seasonable, in the upper 80s to
lower 90s. Lows Friday night will be in the 70s.

Mid level ridge settles over the southern U.S. on Saturday,
while the remnant trough appears to linger over the area at the
surface. Showers and thunderstorms will be possible, with
highest coverage focused over southeast Georgia in proximity to
better moisture and convergence. High temperatures will peak in
the low to mid 90s.
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&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Mid level ridge weakens early next week in response to a
stronger wave passing from the Great Lakes region through the
mid-Atlantic states. This could send a cold front towards the
area, but it is unlikely to make a clear passage. Should see a
return to a more seasonable diurnal convective pattern. Monday
could be the more active day of the set with the approaching
front. Temperatures will heat up with highs forecast to reach
the mid to upper 90s inland of the beaches. With elevated dew
points, it will feel even hotter. Current forecast indicates
heat indices generally peaking around 105, with a few spots up
to 108. Will continue to monitor the potential need for Heat
Advisories. Main question mark will be the extent of convection
and if that will disturb the temperature trends.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
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KCHS/KJZI/KSAV: Little to no chance of any showers at the
terminal Thursday evening. Showers and a few t-storms associated
with a tropical wave to the south will not reach the terminals
until near the very end of this forecast cycle, or beyond. As a
result we have VFR conditions prevailing, with any ceilings
around 3500 feet.

All sites will experience gusty easterly winds yet again late
this morning into the evening, frequently achieving 20-25 kt,
and occasionally stronger.

Extended Aviation Outlook: Flight restrictions will be possible
at all terminals late Thursday night into Friday with low
clouds and showers/thunderstorms moving onshore.
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&&

.MARINE...
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Overnight: Breezy east winds 15-20 kt with gusts to 25-30 kt
will persist across the waters tonight. Seas will average 4-6 ft
nearshore waters and 5-7 ft over the Georgia offshore waters.
Small Craft Advisories remain in effect for all waters through
the night. Winds in the Charleston Harbor have dropped just
below advisory levels, but will remain somewhat elevated through
the night. Waves in the Charleston Harbor will be 1-2 ft.

Thursday through Monday: High pressure will continue to extend
across inland areas while an inverted trough approaches and
eventually moves onshore the Southeast coast late week. This
will drive gusty east-northeast winds over the coastal waters.
Seas also remain elevated, as high as 5-6 ft across nearshore
zones and 6-8 ft beyond 20 nm. These conditions will support a
continuation of ongoing Small Craft Advisories through Friday
morning. For the Charleston Harbor, another Advisory could be
needed for Thursday as wind gusts approach 25 knots. Conditions
will start to improve on Friday. Winds and seas should then
remain below Advisory levels through early next week.

Rip Currents: A High Risk for rip currents will continue
through Thursday across all area beaches. An enhanced risk of
rip currents is expected to persist through the end of the week
as long period swell impacts the region.
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&&

.TIDES/COASTAL FLOODING...
Tides are already more than a foot above astronomical levels,
and with a continued moderate to strong easterly wind, and the
Full Moon to occur Friday evening, those departures could grow
even more. It is possible minor coastal flooding could occur
over the coastal sections of Charleston and Colleton Counties
with the Thursday evening and maybe Friday evening high tide.
Tides elsewhere are forecast to remain below minor flood stage.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
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GA...High Risk for Rip Currents through this evening for GAZ117-119-139-
     141.
SC...High Risk for Rip Currents through this evening for SCZ048>051.
MARINE...Small Craft Advisory until 2 PM EDT Friday for AMZ350-352-354.
     Small Craft Advisory until 11 PM EDT Friday for AMZ374.
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&&

$$

NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...