593
FXUS62 KCHS 221840
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
240 PM EDT Wed Jul 22 2026

.WHAT HAS CHANGED...
All sections have been updated.

&&

.KEY MESSAGES...
- 1) Smoke from the Horse Island Wildfire will impact portions of
  Berkeley County tonight into Thursday.

- 2) Hot and humid conditions across coastal South Carolina and
  Georgia through Thursday. Heat Advisories could be needed.

- 3) A slow-moving front will drift into the area from the north
  and bring increased chances for showers and thunderstorms
  late this weekend and into the weekend. Locally heavy rainfall
  will be possible and could bring a risk of flooding to
  portions of the area.

&&

.DISCUSSION...
KEY MESSAGE 1: Smoke from the Horse Island Wildfire will impact
northeast Berkeley County tonight into Thursday.

The Horse Island Wildfire near Shulerville, SC has increased to 1200
acres. A Dense Smoke Advisory has been requested by the U.S. Forest
Service for portions of Berkeley County in response to the wildfire
smoke. The latest Hysplit output shows the worst of the smoke will
remain across Berkeley County, from Jamestown to the Charleston
border, extending northeast across the Santee River into portions of
Georgetown and Williamsburg Counties. Visibilities may drop below 1
mile at times overnight, especially along parts of Highway 45. Road
closures are possible. Smoke will likely remain an issue into
Thursday although visibilities should improve some by mid-morning as
dispersion increases and mixing heights rise.

KEY MESSAGE 2: Hot and humid conditions across coastal South
Carolina and Georgia through Thursday. Heat Advisories could be
needed.

Deep return flow will remain across Southeast GA and the SC
Lowcountry through Thursday as a cold front slowly approaches from
the north. Near term guidance indicates that the cold front may not
reach the forecast area until late Thursday evening. Given very warm
llvl thicknesses and H85 temperatures, high temperatures are
forecast to reach in the mid to upper 90s. Recent runs of the HRRR
indicate that a sea breeze will develop around 17Z on Thursday. In
the wake of the sea breeze, dewpoints are forecast to increase into
the mid to upper 70s. The rising dewpoints combined with mid to upper
90s, heat index values right along the coast may range from 105 to
109 degrees. Areas inland should see heat index values between 100
to 105 degrees.

High resolution guidance indicates that isolated to scattered
showers and thunderstorms may develop along the sea breeze Thursday
afternoon. These cells could provide some localized relief from the
heat.

KEY MESSAGE 3: A slow-moving front will drift into the area
from the north and bring increased chances for showers and
thunderstorms late this weekend and into the weekend. Locally
heavy rainfall will be possible and could bring a risk of
flooding to portions of the area.

A west to east oriented front is expected to slowly drift southward
into the forecast area beginning Friday. Model consensus suggest
that the front will gradually make southward progress through
Saturday, likely washing out and dissipating by Sunday and Monday.
Along with the front, a corridor of deep moisture is expected to
become aligned across much of the area, with precipitable water
values surging into the 2.25-2.50" range. The presence of the front
and deep moisture is expected to yield increased coverage of showers
and thunderstorms, especially Friday and Saturday. There remains
some question regarding how far south the front will make it, and
current model consensus suggests that it will mostly become aligned
across our southeast SC counties. The setup is expected to favor
rounds of showers and thunderstorms for the Friday through Saturday
time period, with drier conditions returning by Sunday.

The presence of rounds of convection and deep moisture will
certainly be capable of producing locally heavy rainfall. General
rainfall amounts of 1-3 inches appear likely, especially for
southeast SC and lesser amounts across southeast GA. Locally higher
amounts are certainly possible, and will depend greatly on where
convection sets up and if any areas see multiple rounds of storms.
Locally excessive rainfall is a concern, and the flooding
potential will have to be monitored. The Weather Prediction
Center (WPC) continues to highlight southeast SC in a Marginal
Risk for excessive rainfall for Friday and Friday night, and
then the entire area in a Marginal Risk for excessive rainfall
Saturday and Saturday night.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
18Z TAFs: VFR generally expected across the terminals through the
TAF period. Gusty south-southwest winds may persist through the rest
of the daylight hours. Once mixing begins Thursday morning, SW winds
may increase to around 10 kts.

Extended Aviation Outlook: Chances of flight restrictions increase
later this week with a greater coverage of showers/thunderstorms.

&&

.MARINE...
Tonight: Breezy south-southeasterly winds will continue across the
local waters as a cold front approaches from the north and east-west
surface ridge remains to the south. This will maintain hazardous
conditions through this evening. Small Craft Advisories are in
effect for all marine zones into tonight. As south-southwesterly
swell tapers back, seas will range from 3 to 4 ft.

Thursday through Sunday: Small Craft Advisories are expected to end
by Thursday morning. As the aforementioned front stalls in the
vicinity, the pressure gradient will relax back and marine
conditions should become rather benign through Sunday. Seas will
range from 2 to 4 ft.

Rip Currents: A Moderate Risk of rip currents is expected to
continue along the South Carolina and Georgia beaches through this
evening. There is also a Moderate Risk tomorrow (Thursday), however
it is just for the Charleston County beaches. Although surf is
expected to subside a little bit on Thursday, a longer-period swell
of around 8 seconds should continue to support dangerous rip
currents (esp. for the Charleston County beaches). The is a low risk
of rip currents on Friday.

&&

.CLIMATE...
Record High Temperatures:

July 23:
KCHS: 99/2015

Record High Minimum Temperatures:

July 22:
KCHS: 81/2011
KCXM: 83/2011

July 23:
KCHS: 80/1991
KCXM: 83/1952

July 24:
KCHS: 81/2024

July 25:
KCHS: 80/2011
KCXM: 82/2016
KSAV: 80/1893

July 26:
KCHS: 78/2025

July 28:
KCHS: 80/2025

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Dense Smoke Advisory from 8 PM this evening to 10 AM EDT
     Thursday for SCZ045.
MARINE...Small Craft Advisory until 5 AM EDT Thursday for AMZ360-362.
     Small Craft Advisory until midnight EDT tonight for AMZ364-384.

&&

$$

BSH/NED