656
FXUS62 KCHS 161050
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
650 AM EDT Mon Jun 16 2025

.SYNOPSIS...
Atlantic high pressure will continue to build across the
Southeast through the week. A cold front could move through
Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: The majority of the CAMs guidance indicating that
coverage of convection will be quite a bit less than past
several days. This downward trend in convective coverage is
likely due to the gradual increase mid/upper ridging from the
southeast into the area as the trough well to the northwest
decreases. Model guidance also points toward a later start to
convection, with the seabreeze being the main activating feature
at low levels. There may also be convective complex that moves
well north of the area later this afternoon/early evening, which
may put out boundaries into our northern area, especially
Berkeley county. Have kept generally chance PoPs most of the
area, with slightly higher PoPs closer to the coast with the
seabreeze. Temperatures expected to be above normal, generally
in the upper 80s to lower 90s. Given surface dewpoint
temperatures remain in the lower 70s this afternoon, max heat
indices could reach 100-103 in some areas.

Tonight: Any convection should be on the decrease after sunset.
Continued very mild with lows in the lower to mid 70s, and
upper 70s to near 80 closer to the coast.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Upper level ridging with a surface high pressure over the Atlantic
continues throughout the short term, though the ridge begins to
break down by late in the day Thursday as dry air is advected in
from the south. Recent model runs have portrayed weak daytime upper
level ridging occurring on Tuesday and Wednesday, which has
decreased chances for daily showers and thunderstorms, albeit
20-40% chances still exist during the afternoon hours. 1500-2000
J/kg of CAPE will continue to lead to very isolated chances for
severe weather, though the lack of upper level flow will keep
such activity rather brief. On Thursday, a mid-level shortwave
begins to move in from the west, which will start to flatten the
ridge over the area as it builds westward over the CONUS
southern great plains. Out ahead of an approaching cold front,
another round of showers and thunderstorms are possible
(20-30%), with the main question being whether or not the front
reaches the area...most guidance indicates it stalls off to our
northwest.

As the ridge strengthens, expect temperatures to continue increasing
each day. NAEFs and ECMWF ensemble situational awareness tables
(ESATs) continue to show the region remaining near/above the 90th
percentile of climatology with respect to geopotential heights from
850mb up to 200 mb, though lower-level (700-850mb) temperatures
remain below the 90th percentile of climatology. This will keep
afternoon highs in the lower to mid 90s on each day, while those
near the coast remain in the mid/upper 80s. Heat index values in the
mid 90s to lower 100s are expected, possibly as high as mid to upper
100s if higher dewpoints in the upper 70s are realized.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
The upper level ridge builds/shifts westward as the aforementioned
weak trough moves into the northeast overnight into Friday.
Temperatures remain largely in the lower to mid 90s, with daily
chances (20-40%) for showers and thunderstorms continuing into the
weekend.

Behind the exiting upper level trough, deterministic and ensemble
models continue to show a ridge building aloft as it moves eastwards
towards the east coast. Highs each day will be in the low to mid 90s
with heat indices topping out 100-105F.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Today: VFR conditions to prevail through early afternoon.
Scattered showers and thunderstorms expected to develop by
mid/late afternoon, which could produce brief flight
restrictions at each terminal. Model guidance continues to trend
lower for rain chances this afternoon, and start convection
later than the past several days. Winds may gust briefly to
15-20 knots late morning into early afternoon at the atmosphere
mixes. However, winds arethen expected to generally be SSW at
8-12 knots rest of day.

Tonight: Any onconvection should dissipate during the evening.
After 00z, expect conditions VFR all sites.

Extended Aviation Forecast: Brief flight restrictions are possible
in showers and thunderstorms each day, mainly in the afternoon.

&&

.MARINE...
Today and Tonight: No highlights are expected during the period.
However, winds may gust near 20 kts in Charleston Harbor and the
nearshore regions of AMZ350 this afternoon with the seabreeze
backing winds to more southerly near the coast in the afternoon.
Otherwise, generally south-southwest winds of 10-15 knots with
seas 2 to 4 feet, highest seas beyond 10 or 15 nm offshore. A
background long period swell from the east-southeast will still
be present.

Tuesday through Saturday: Typical summertime conditions will prevail
over the waters with high pressure centered offshore of the
Southeast States. A broad, southerly wind regime can be expected
with winds generally averaging 15 kt or less, except a bit higher
along the land/sea interface and Charleston Harbor each afternoon
with the sea breeze which could exceed 20 knots through Thursday.
Seas will remain 4 ft or less through the period.

Rip Currents: An easterly swell surge with 9 second swells continues
today, and coupled with locally breezy conditions near the afternoon
sea breeze will support a moderate rip current risk for all beaches
today. Currently have low risk for rip currents expected for Tuesday
as wave heights remain near 3 feet and swells below 6 seconds,
though for the GA beaches there may be a period during the day where
swells reach 8-9 seconds and could result in brief moderate risk for
rip currents.

&&

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

&&

$$

NEAR TERM...RFM
SHORT TERM...APT
LONG TERM...APT
AVIATION...RFM
MARINE...APT/RFM