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515
FXUS62 KCHS 242355
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
755 PM EDT Mon Jun 24 2024

.SYNOPSIS...
High pressure will remain over the western Atlantic while a
weak cold front approaches the area. This front will likely
linger near the area through mid-week.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Tonight: A notable differential heating boundary created by clouds
near the coast vs mostly sunny skies well inland late day has been
the focus of a few showers/thunderstorms developing along/near a sfc
trough axis just upstream of the local area. This activity could
drift across inland zones during the next few hours as the trough
nudges toward the Southeast Coast through the night, with a low, but
non-zero risk for a stronger thunderstorm across far inland
locations during the next few hours. By mid evening, some guidance
suggests the tail-end of convection moving across the Tri-County
Area and interacting with a sea breeze, sparking off additional
showers and thunderstorms, a few of which could become strong with
gusty winds given DCAPE values in excess of 1000 J/kg, 0-3km lapse
rates around 7.5 to 8 C/km and the position of the trough axis
nearby. However, instability will be on the downward trend during
this time frame, and should limit the overall severe weather risk
locally. Once convection moves offshore and/or dissipates, a
warm/humid night will remain in place with lows ranging in the low-
mid 70s well inland to lower 80s at the beaches and Downtown
Charleston.
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&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
Broad troughing will persist across the East Coast on Tuesday,
gradually shifting to zonal flow on Wednesday and a return to
broad troughing Thursday. At the surface a weak cold front will
likely linger in the vicinity of the forecast area through
midweek. 850 hPa temperature anomalies will remain rather warm
through the period, which combined with little mixing each day,
will yield hot and humid conditions. Heat index values are
forecast to reach 102-107F inland. A few spots may make a run at
108F along the coastal counties, however coverage of these
values is not enough to warrant Heat Advisories at this
juncture. Each afternoon isolated to scattered showers and
thunderstorms will be possible, as PWATs remain elevated with
the front in the vicinity. PWAT values are forecast to remain
near 1.6-1.8", which is slightly above normal for this time of
year. CAPE values are forecast to reach around 1500 J/kg, with
model soundings indicating >1000 J/kg of DCAPE. A strong to
marginally severe thunderstorm cannot be ruled out any
afternoon, with strong wind gusts as the main hazard.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
An anticyclone aloft will be positioned over the southern U.S.
and will slowly shift eastward over the southeastern states
through the weekend. At the surface high pressure will extend
into the forecast area from the east with the center of high
pressure centered over Bermuda. Hot and humid conditions will
likely persist into the weekend. Head index values are forecast
to reach from around 103- 105F inland with values approaching
108F along the coastline. Head Advisories may be required. A
summertime pattern is expected through the period, with the
highest precipitation chances in the afternoon hours.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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VFR conditions will prevail at CHS/JZI/SAV terminals through 00Z
Wednesday. However, a few showers could briefly impact the
CHS/JZI terminals this evening (02-05Z), causing a short period
of flight restrictions. VCSH remains at CHS to account for this
possibility during the time noted above, but the overall concern
is rather low. A few showers and/or thunderstorms could impact
the terminals Tuesday afternoon, leading to tempo flight
restrictions at any terminal, but confidence in timing/duration
is too low to include in the latest TAF issuance.

Extended Aviation Outlook: Brief flight restrictions will be
possible at all terminals with afternoon showers and
thunderstorms.
-- End Changed Discussion --

&&

.MARINE...
Tonight: The pressure gradient will remain enhanced this evening
between high pressure centered well offshore and a trough advancing
toward the coast. As a result, south to southwest winds between 15-
20 kt will be common across local waters, with even a few wind gusts
up to 25 kt at times, but the duration of stronger gusts should be
short-lived and not sufficient for a Small Craft Advisory. A few
stronger thunderstorms could impact coastal waters this evening,
primarily across South Carolina waters until the trough advances
offshore. Expect southwest winds to slightly weaken once fropa
occurs later tonight, with gusts upwards to around 15 kt across
nearshore waters and perhaps 20 kt across offshore Georgia waters.
Seas will average between 3-5 ft, largest beyond 10 nm from the
coastline.

Tuesday through Friday: Generally tranquil marine conditions
are expected through the period. Winds will gradually back each
day and veer overnight, strongest along the coastline as the
afternoon sea breeze/overnight land breeze develops. Seas should
average 2 to 3 ft.

&&

.CLIMATE...
The low temperature at KCHS so far today is 80. If this holds,
this will break the previous record high minimum of 79 set back
2016.

&&

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

&&

$$

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