455
FXUS62 KCHS 301821
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
221 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/...
The region will remain on the backside of surface high pressure
centered offshore tonight, while a broad trough resides inland.
Aloft, a weak upper level wave will shift westwards towards the
Southeast coast. Concurrently, a larger scale trough will be moving
into the Ohio and Tennessee Valleys. Diurnal showers and thunderstorms
will continue to pop-up through the afternoon and into this evening
with SPC mesoanalysis indicating 1500-2000 J/kg of MLCAPE.
Highest coverage should be focused over southeast Georgia where
PoPs peak in the 60-70% range. Further north into South
Carolina, PoPs remain 20-30%. The threat for severe weather is
low. Convection will largely diminish later this evening and
overnight with loss of heating. Low temperatures will be near
normal, mainly in the low to mid 70s, except a bit higher at the
beaches and immediate coast.

&&

.SHORT TERM /TUESDAY 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 SUNDAY/...
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 /18Z MONDAY THROUGH SATURDAY/...
KCHS and KJZI: Prevailing VFR is expected through the 18z TAF period
as the threat for convection is too low to include in the TAF.

KSAV: There could be brief restrictions in ceilings and visibilities
this afternoon if any showers or thunderstorms make a direct impact
at the terminal. Outside of convection, there are some indications a
period of sub-VFR ceilings could develop late tonight towards
morning, but opted for a SCT layer at this time until trends are
better defined.

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: Southerly flow is expected to prevail through tonight on
the backside of surface high pressure. Speeds average 10-15 kt with
seas 2-4 feet.

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...ETM
SHORT TERM...BSH
LONG TERM...BSH
AVIATION...BSH/ETM
MARINE...BSH/ETM