597
FXUS62 KCHS 010145
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
945 PM EDT Mon Jun 30 2025

.SYNOPSIS...
A front is expected to move into the area by Wednesday and
could then linger in the vicinity into the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Showers and thunderstorms from this evening have now finally
dissipated over Southeast Georgia. As the region remains on the
backside of this Bermuda High centered offshore, a upper-level
trough will set up over the Great Lakes overnight.
Simultaneously, a weak shortwave will shift westward towards the
Atlantic seaboard. At the surface, southwest winds will remain
elevated between this pinched pressure gradient. This will be
enough to keep any fog from developing overnight. Skies will
keep mostly clear, with coverage increasing across the far
interior Georgia counties in the early morning (~10-11Z). Low
temperatures will be near normal, mainly in the low to mid 70s,
except a bit higher at the beaches and immediate coastline.

&&

.SHORT TERM /7 AM TUESDAY MORNING THROUGH THURSDAY/...
Tuesday through Thursday: Aloft, we begin Tuesday with a baggy upper
trough that steadily becomes more well defined and sharper into
Wednesday as a shortwave passes by to the north. At the surface,
Tuesday will see the area situated between the subtropical high to
the east and a front to the west that stretches from the eastern
Great Lakes into the lower MS Valley. This front is expected to
gradually shift closer to the area through Wednesday and perhaps
remain in the vicinity through Thursday. Also of note, precipitable
water values are expected to surge for Wednesday with the entire
forecast area within an area of 2.25" or higher values. Concerning
the coverage of convection, the overall trend is expected to be
increasing especially for Wednesday when we anticipate seeing the
best combination of forcing and moisture. Slow moving storms and the
overall expected increased coverage for Wednesday will also likely
yield the greatest potential for locally heavy rainfall across the
area. Overall, there is no notable severe threat, though there could
always be a strong to marginally severe storm as outflow boundaries
interact. Temperatures are expected to be near normal for Tuesday,
then perhaps a bit below normal on Wednesday thanks to the increased
shower and thunderstorm coverage. Thursday should be back to near or
slightly above normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The pattern for Friday through the weekend and into early next
week looks to be pretty typically of summer. The one thing to
keep an eye on is that some model guidance keeps the mid/late
week front lingering along the coast and attempts to develop an
area of low pressure along it. As such, the northeast Gulf Coast
and Southeast coast are currently highlighted in NHC`s Tropical
Weather Outlook with a low chance of tropical development over
the next 7 days. But for now, the forecast highlights low 90s
for highs each day with scattered diurnal convection.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
00Z TAFs: Convection from this evening has now dissipated at
all terminals and now settling into a clear night. As the region
remains on the backside of this surface high pressure centered
offshore, an upper-level trough will float into the Great Lakes
region, with the southern periphery over the Southeastern CONUS.
This will result in pinched pressure gradient over the region,
and winds might become quite gusty (20-22KT) over Tri-County
tomorrow by the late morning/early afternoon. The highest
chance of convection will be across inland/coastal Georgia in
the afternoon as the seabreeze pushes inland. Thus, convection
was left out of the forecast at this time for KCHS/KJZI.

Extended Aviation Outlook: Mostly VFR. There is potential for
brief impacts from thunderstorms each afternoon and evening
with the best chances coming during the mid week time period as
a front moves into the region.

&&

.MARINE...
Tonight: As the local waters remain on the backside of this
Bermuda High, the pressure gradient will continue to tighten and
allow southwesterly winds to remain elevated at 10 to 15 kt with
gusts up to 20 kt. Weak south-southeasterly swell with a 4 to 6
second period will dominate the local waters tonight, and allow
for a choppy set up of waves. This will also set up a moderate
display of sideshore winds and poor conditions for surf will
change over. Expect seas to range from 2 to 4 ft.

Tuesday through Saturday: The local waters are expected to be
situated between high pressure to the east and an inland front
Tuesday and Wednesday, which should lead to the highest period of
winds and seas. In fact, Tuesday should produce solid 15 knot winds
with frequent gusts to 20 knots across all local waters. The
strongest winds are expected for Charleston Harbor and the
Charleston County waters where there is some potential for gusts up
to 25 knots. Confidence isn`t high enough to go with a Small Craft
Advisory at this point, but it will need to be considered with
future forecast updates. After another period of some enhanced winds
Wednesday, speeds should be much lower from Thursday onward. Seas
should peak in the 3-4 ft range Tuesday, then diminish back to be 2-
3 ft thereafter.

Rip Currents: The presence of some swell energy and enhanced flow
along the Charleston County coast will yield an elevated risk of rip
currents for Tuesday. There is a Moderate Risk for the Charleston
County beaches and a Low Risk elsewhere.

&&

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

&&

$$

NEAR TERM...Dennis
SHORT TERM...BSH
LONG TERM...BSH
AVIATION...BSH/Dennis
MARINE...BSH/Dennis