Severe Thunderstorm Warning 10, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
234 PM EDT Fri Jun 12 2026

.WHAT HAS CHANGED...
All Key Messages and sections were updated.

&&

.KEY MESSAGES...
- 1) Afternoon heat index values could climb into the 105 to 112
  degree range across the I-95/coastal corridor on Saturday.

- 2) Daily coverage of showers and thunderstorms expected to
  increase through the weekend and into next week as a more
  typical summertime pattern returns to the region.

- 3) Minor coastal flooding possible along Charleston and
  Colleton County coasts during evening high tides this weekend
  into early next week.

&&

.DISCUSSION...
KEY MESSAGE 1: Afternoon heat index values could climb into the 105
to 112 degree range across the I-95/coastal corridor on Saturday.

Showers and thunderstorms have developed across the forecast area
this afternoon, slow storm motions to the east. Some of these storms
have tapped into SBCAPE in excess of 3000 J/kg, to develop 50dBZ
cores near 40 kft. Strong to severe thunderstorms are possible this
afternoon, for localized damaging wind gusts. KCHS set a new record
high of 98, breaking the old record of 97 set in 2016.

On Saturday, the day should begin will very warm temperatures in the
upper 70s, possibly near 80 along the coast. Much like today,
temperatures should warm into the 90s by mid-day, then peak near
record values in the upper 90s. See Climate section below for
temperature records. These temperatures combined with dewpoints well
into the 70s could yield index values in the 108-112 degree
range. It is possible that a Heat Advisory will be needed for
the coastal counties tomorrow. However, temperatures should
exceed the convective temperature in the low 90s around mid-day.
Initially, cumulus cloud cover should rapidly develop across
the forecast area, then showers and thunderstorms should begin
to develop shortly afternoon. Given the hot and humid
conditions, it is possible that SBCAPE will build in excess of
3000 J/kg along and ahead of the sea breeze. Thunderstorms
should develop along and inland of the sea breeze, then track
across the sea breeze towards the coast. 12Z HREF indicates a
70% of rainfall rates of 1"/3hr along the coast, with some
pockets of 10% 3"/3hr. It is possible that a SVR warning or
Flood Advisory will be needed on Sat. Rainfall could become
excessive if heavy downpours overlap with the early evening high
tide.

KEY MESSAGE 2: Daily coverage of showers and thunderstorms
expected to increase through the weekend and into next week as a
more typical summertime pattern returns to the region.

Through the weekend and into next week, the pattern across southeast
GA and southeast SC will gradually shift toward a typical summertime
pattern supportive of showers and thunderstorms each day. Aloft, the
ridging that has been in place for the last several days will break
down and be replaced by a more zonal flow through Sunday. Then as we
head into the early and middle part of next week, large and broad
troughing is expected to encompass the eastern half of the CONUS. At
the surface, a weak front/trough is expected to drift into the
vicinity Saturday and Sunday, followed by a more notable front for
the early to middle part of next week. Overall thinking is that
Saturday and Sunday will result in a modest increase in convective
coverage. A more significant increase in coverage is likely in the
early to middle part of next week due to the combination of the
presence of the trough aloft and the aforementioned front.

For Saturday and Sunday, mid-level flow should be such that it only
support storm motions on the order of 10-15 knots. Precipitable
water values will be in the 1.8-2.0" range as well. So locally heavy
rainfall is possible due to slow storm motion, but coverage should
be limited to the point of keeping the threat localized. As we move
into next week, mid-level flow will increase into the 20-30 knot
range and the threat for heavy rainfall will come primarily from
training storms and the presence of precipitable water values in
excess of 2 inches. Overall, the severe risk for each day is
relatively low due to the lack of organization. Also, the freezing
level (14.5-15.0 kft) and -20C (25.0+ kft) height will be quite high
each day which means it will take a very tall storm to produce a
damaging wind gust threat. The best chance for a strong to severe
storm will come where boundary interactions occur and boost updraft
strength. This could change a bit into next week as the mid-level
flow improves.

KEY MESSAGE 3: Minor coastal flooding possible along Charleston and
Colleton County coasts during evening high tides this weekend into
early next week.

Breezy south-southeasterly winds post sea breeze each day along with
the upcoming lunar Perigee (June 14th) and New Moon (June 15th)
should result in elevated tidal departures above 1/2 ft this weekend
into early next week, setting the stage for minor coastal flooding
along the Charleston and Colleton County coasts during evening high
tide cycles. The latest TWL forecast calls for 7.1 - 7.3 ft MLLW in
the Charleston Harbor Saturday evening, and similar water levels are
possible during evening high tides into early next week as
astronomical influences peak and breezy onshore winds persist.
Coastal Flood Advisories could eventually be needed.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Prior to the 18Z TAFs, KCLX detected showers in the vicinity of each
terminal. The TAFs will feature a TEMPO during the heat of the day
to indicate the potential of a moderate shower. Overnight,
conditions should remain VFR with light SW winds. The sea breeze is
expected to trigger showers and thunderstorms by early afternoon.
KJZI and KSAV TAFs will highlight VCSH by 17Z Sat.

Extended Aviation Outlook: VFR conditions should prevail at
CHS/JZI/SAV terminals through the weekend, although TEMPO flight
restrictions are possible with afternoon showers/thunderstorms
throughout the weekend. Chances for flight restrictions increase
early next week with shower/thunderstorm coverage expanding locally
ahead of an arriving cold front.

&&

.MARINE...
Tonight through Saturday, the pressure pattern will support
southwest winds between 15 to 20 kts. Wave heights are forecast
to remain between 2 to 3 ft.

Sunday through Wednesday: The gradient across the local waters will
get enhanced a bit as a surface trough takes hold inland. This
should drive southwest flow into the 15-20 knot range across all the
waters, with potential for 25 knot gusts across the SC waters and
the outer GA waters. Similar wind speeds will be possible each day
into the middle of the week, primarily in the afternoon and evening
time period. Conditions could become marginally supportive of Small
Craft Advisories at times for portions of the waters.

&&

.CLIMATE...
Record High Temperatures:

June 12:
KCHS: 97/2016 *New record of 98 degrees set.
KCXM: 97/1998
KSAV: 100/1977

June 13:
KCHS: 99/2011
KCXM: 96/1998

June 14:
KCHS: 99/2010
KCXM: 97/1981

Record High Minimum Temperatures:

June 11:
KCHS: 76/2020
KCXM: 79/2020
KSAV: 76/2010

June 12:
KCHS: 77/1986
KCXM: 80/1998
KSAV: 78/1899

June 13:
KCHS: 80/2013
KCXM: 82/1998
KSAV: 80/1880

June 14:
KCHS: 79/2010
KCXM: 81/2010

&&

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

&&

BSH/NED

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>