470
FXUS62 KCHS 141550
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1150 AM EDT Sat Jun 14 2025

.SYNOPSIS...
Atlantic high pressure will build across the Southeast U.S.
through the weekend into next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Showers/tstms are starting to get going across the interior
which is about an hour earlier than expected. Near term pops
were adjusted to reflect current radar trends. Overall, no major
changes were made with the noon update.

This Afternoon: The region will remain situated between
subtropical high pressure centered well offshore of the
Southeast U.S. and a broad weakness over the lower Mississippi
Valley. The airmass across the region remains warm and humid
with surface dewpoints in the 70s and PWATs within a tenth of an
inch of 2.0 inches. 12z composite theta-e analysis showed a
sliver of dry air along and east of I-95 with some modest 850
hPa theta-e pooling noted west of there. Near term guidance
keeps this corridor of dry air over the coastal counties through
early afternoon, which may help delay convective initiation at
the coast and near the sea breeze until after 2 PM. Farther
inland, convection should begin to fire by noon with activity
gradually focusing closer to the coast as the afternoon
progresses and convective outflows are generated. Hourly pops
were adjusted slightly to reflect this idea, but net pops 50-70%
were mostly maintained. A few strong to marginally severe tstms
will be possible through early evening with weak shear in
place. Gusty winds, cloud to ground lightning and locally heavy
rainfall will be the primary hazards. The risk for an isolated
severe tstm will be highest near mesoscale boundary collisions.

Tonight: Convection should reduce in coverage after sunset.
However, isolated showers may linger through at least midnight,
with weak upper forcing and ample moisture/instability. Lows in
the lower to mid 70s inland, and the mid to upper 70s closer to
the coast.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
Daily chances for showers and thunderstorms continue as the surface
Atlantic high pressure remains off to our east, and an upper level
high is parked off to our south-southeast. While this won`t lead to
constant rain, highest probabilities and spatial coverage for rain
are expected through the late morning and into the afternoon hours
as instability builds, with chances decreasing into the overnight
hours as instability wanes. While severe weather can`t be entirely
ruled out given 1-2 J of MUCAPE, the lack of strong forcing and
weak mid-upper level flow will keep such activity isolated at
best. This is further validated by various AI/ML models, as well
as the SPC keeping chances for severe weather below 5%. With
precipitable water remaining above 1.75", locally heavy rainfall
can`t be ruled out.

As for temperatures, they are expected to slowly increase into the
beginning of the week given the persistent pattern underneath the
aforementioned upper level high. Both the 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 per the NAEFS and
ECMWF, resulting in afternoon highs on Sunday in the upper 80s to
lower 90s and lower to mid 90s on Monday and Tuesday, while those
near the coast remain in the mid/upper 80s. Heat index values in the
mid 90s to lower 100s are also expected, possibly as high as mid
100s on Monday and Tuesday if dewpoints rise into the upper 70s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
The aforementioned pattern continues while the upper level ridge
begins to slowly build westward as a weak trough moves into the
northeast Thursday into Friday. Daily chances for showers and
thunderstorms continue, with temperatures remaining in the lower to
mid 90s. Currently have heat indices largely remaining below Heat
Advisory criteria of 108 degrees F, but that will need to be
closely monitored.

&&

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
14/18z Aviation Discussion:
KCHS/KJZI/KSAV: Showers/tstms are starting to develop and should
primary be an issue for KCHS and KSAV as the sea breeze meanders
past KJZI. Near term guidance favors KCHS for the greatest
impacts, so a TEMPO for MVFR conditions in TSRA was introduced
21-24z, although this may need to be moved up pending last
minute radar trends. VCTS was highlighted for KSAV and KJZI
through 00z for now, but again, last minute radar trends may
change this approach. VFR will prevail overnight for all
terminals.

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

&&

.MARINE...
Today through Tonight: No significant changes were made with
the early morning update. Although winds will gust to near 20
knots today, winds/seas are not expected to reach SCA levels
during this period. Deep layer high pressure will remain
southeast of the waters with deep layer troughing well
inland/west of the waters. This will keep south-southwest winds
of 10-15 knots in place, gusting to near 20 knots during the
afternoon as the seabreeze develops, but likely stays close to
the coast. Seas generally 2-3 feet within 10 nm of the coast,
and 3 to 4 feet beyond 10 nm.

Sunday through Thursday: 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. Seas will remain 4 ft or less through the
period.

Rip Currents: An easterly swell surge will arrive along the
Charleston County beaches today and all remaining beaches for
Sunday. This coupled with locally breezy conditions near the
afternoon sea breeze will support a moderate rip current risk for
the Charleston County beaches Saturday and for all beaches
Sunday.

&&

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

&&

$$