419
FXUS62 KCHS 011101
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
701 AM EDT Tue Jul 1 2025

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

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: A weak land breeze has developed this morning with a few
showers along the boundary. This weak line of showers will
likely translate to the east or slightly further offshore
through the early morning hours. In the upper levels of the
atmosphere the TUTT continues to slowly retrograde west with dry
air noted on the northwest flank. This was analyzed yesterday
on water vapor and remains a prominent feature in the KCHS
01.00z sounding. Simultaneously at the surface, Bermuda high
pressure remains anchored across the central Atlantic, with the
ridge axis extending across the Gulf of America. This has helped
to produce westerly flow over Georgia, while southerly flow
remains established over South Carolina. The above setup has
favored a convergent zone across coastal/ inland Georgia and
inland South Carolina. The sea breeze has pushed inland
relatively quickly over South Carolina the last couple of days and
this thinking remains unchanged. As such, most of coastal South
Carolina will likely remain dry today with inland Georgia again
being fairly active. Expect high temperatures around 90
degrees.

Tonight: Cloud cover will slowly increase overnight as a mid-
level wave approaches from the west with a cold front
approaching the Upstate of South Carolina. Winds will also
remain elevated overnight/ not fully decouple given the
tightening pressure gradient. This will keep low temperatures
relatively mild or in the low to mid 70s.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
Wednesday: Troughing will dominate across the eastern CONUS in the
upper levels, with the southern portion of the trough over the
southeastern states. At the surface a cold front will approach from
the west, likely stalling in the vicinity of the SC Midlands. Ahead
of the approaching cold front moisture will increase, with PWAT
values approaching 2.3 inches. Numerous to widespread showers and
thunderstorms are forecast, given the ample moisture and CAPE values
around 1600 J/kg. While there will be enough instability for
convection to form, the overall severe threat remains low. More of
note will be the possibility for heavy rainfall and the chance of
minor flooding of low lying and poor drainage areas. The region
remains outlooked in a Marginal Risk for Excessive Rainfall by WPC.
High temperatures will only reach into the upper 80s to around 90,
given the increased coverage of precipitation.

Thursday and Friday: Models are generally in agreement that the
stalled front will weaken and wash out late this week and the region
will see a return to just scattered coverage of afternoon showers
and thunderstorms. There is a chance, however, that the front
remains stalled in the vicinity and a low pressure develops along
it. The northeast Gulf Coast and Southeast Coast continue to be
highlighted in NHC`s Tropical Weather Outlook with a low chance of
tropical development over the next 7 days. If a low is able to
develop along the stalled front, precipitation chances will increase
both Thursday and Friday. As of this juncture, the forecast has
trended towards no low development and a return to near climo PoPs.
High temperatures will reach into the mid to upper 90s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A typical summertime pattern is in store through the long term
period as high pressure builds in both aloft and at the surface. The
forecast features scattered afternoon showers and thunderstorms and
high temperatures in the low to mid 90s. It is worth noting that
there is a low-end chance that the aforementioned stalled cold front
may linger in the vicinity with a low pressure developing along it.
The northeast Gulf Coast and Southeast Coast remain highlighted in
NHC`s Tropical Weather Outlook with a low chance of tropical
development over the next 7 days.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
01.12Z TAFs: KSAV is currently IFR this morning as a widespread
stratus deck has formed is approaching from the southwest.

As the sun rises this morning winds will start to increase in
speed as the pressure gradient begins to increase across the
terminals (from an approaching area of low pressure). The
stratus deck will also slowly rise to VFR. Both the GFS and NAM
forecast soundings support wind gusts up to 25 kt at all the
terminals this afternoon via momentum transfer techniques. As
was the case yesterday, the upper level low will remain just
southeast of the area with dry air on the northwest flank of the
low. This dry air really limited convection across the
Charleston terminals (KCHS/ KJZI), with more focused convection
just west of KSAV. The upper level low is slightly further west
today compared to yesterday, so initial thinking is most
convection will be west of KSAV but can`t be completely ruled
out.

Extended Aviation Outlook: Mainly VFR. Wednesday should see
widespread coverage of showers and thunderstorms as a cold front
approaches from the northwest. Flight restrictions will be possible
mainly Wednesday afternoon.

&&

.MARINE...
Today and Tonight: Bermuda high pressure will remain anchored
across the central Atlantic as surface low pressure approaches
from the west. The pressure gradient is expected to continue to
tighten this morning (with gusts already near 25 kt this morning
in AMZ350). Over Charleston Harbor and the Charleston nearshore
adjacent waters, SCA criteria will likely begin to be met late
this morning with wind gusts up to 30 kt. Seas will also begin
to build 4 to 5 ft. Weak south-southeasterly swell with a 4 to 6
second period will dominate the local waters, 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.

Wednesday through Sunday: A cold front will approach the region
on Wednesday, possibly stalling in the vicinity through the
weekend. Generally conditions across the marine waters will
feature southerly winds 10 to 15 knots Wednesday, shifting to
the NE Thursday and through the weekend. Seas are forecast to
average 2 to 4 ft. It is worth noting that the northeast Gulf
Coast and Southeast Coast remain highlighted in NHC`s Tropical
Weather Outlook with a low chance of tropical development over
the next 7 days. If a low pressure is able to develop along the
stalled front higher wind gusts and building seas will be
possible.

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...Small Craft Advisory from 11 AM this morning to 9 PM EDT this
     evening for AMZ330-350.

&&

$$

NEAR TERM...Haines
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...CPM/Haines
MARINE...CPM/Haines