Severe Thunderstorm Warning 56, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
729 PM EDT Thu Jul 20 2023

.SYNOPSIS...
A weak front will stall over or near our area late this week
through early next week, followed by high pressure toward the
middle of next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
The Storm Prediction Center has issued Severe Thunderstorm Watch
#529 in effect for the entire forecast area except the offshore
GA waters until 1 am Friday. We continue to watch an expanding
MCS over northern GA/SC pushing southeast into a very unstable,
untapped airmass. Over our area, SBCAPE ranges from 3,000-3,500
J/kg, LIs are -7C, DCAPE ranges from 800 over southern SC to
1200 J/kg over far southern GA. Effective bulk shear is
currently around 25 kt over southern SC but is forecast to
increase to 30-35 kt by late evening as the upper vort
approaches.

Isolated strong/severe convection has been developing over
eastern Berkeley County, SC but so far this activity has not
expanded. The sea breeze is very slowly pushing inland and could
eventually intersect what little convection has already
developed, potentially resulting in some expansion in coverage.
The main concern is the upstream MCS trekking southeast. This
activity would probably not reach our far northwest zones until
after 830 PM, pushing off the coast by midnight, assuming it
holds together that entire time. The main concern will be
damaging straight line winds, though a few cells could contain
marginally severe hail as well.

Even after the main MCS moves through late this evening and
early Friday morning, we could see additional convection moving
through late tonight, though probably not severe.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
As the upper ridge over the north central Gulf Coast continues
to weaken, a quasi-zonal flow will develop over the Southeast. A
weak surface front will sag southeast and stall over or near the
forecast area through the weekend. Mid-levels will become less
capped and more conducive to convective development. Occasional
upper shortwaves are expected to drop through the area, but
timing these features will be nearly impossible.

On Friday, the sea breeze will likely remain pinned near the
coast for much of the day due to deep westerly flow. A shortwave
may drop into southeast GA late in the afternoon or early in the
evening, bringing a cluster of thunderstorms. The environment
should be quite favorable for strong thunderstorms given CAPE >
2,000 J/kg, DCAPE > 1,000 J/kg, Lifted Indices around -8C, and
25-30 kt of bulk shear. All of our southeast GA zones and a
portion of southern SC is highlighted in a Slight Risk from the
Storm Prediction Center. High temps will reach the mid to upper
90s with dewpoints in the low to mid 70s, at least earlier in
the day. Dewpoints may mix out a bit during the hours of highest
temps, so heat indices will probably top out no higher than
110F.

A very moist environment will exist Saturday through Sunday,
particularly across southeast GA where PWATs could exceed 2.2".
As a weak upper trough pattern develops and several shortwaves
move through, we should see considerable convective development,
mainly during the peak heating hours. The greatest coverage is
expected over southeast GA where the deeper moisture will
reside. High temps will be in the low to mid 90s both days.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A fairly typical summertime pattern will develop next week as
the upper trough shifts east and a broad upper ridge sets up.
Mainly diurnal convection is expected with highs temps in the
low 90s.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
The main aviation concern is the potential for a cluster of
thunderstorms to move through late this evening into the early
Friday morning hours. High-res guidance indicates the most
likely trajectory for the storms is through southeast SC
between 02-05Z. It's less clear if KSAV will be directly
impacted. We cannot rule out isolated convection again later
tonight but chances are too low to include in 00Z TAFs.

More storms could develop and move through on Friday, but the
timing details are murky. Some showers or storms could move
through during the morning but the best chance will be during
the evening as another upper disturbance moves through.

Extended Aviation Outlook: Mainly VFR, outside brief convection
at any of the terminals.

&&

.MARINE...
A slightly enhanced gradient will result in some 25 kt gusts
tonight. Based on the 18Z guidance, the best chance for 25 kt
gusts will be through the early morning hours, with winds
beginning to taper off late tonight. We therefore updated the
forecast to trim back the end time of the Small Craft Advisories
to 4 am Friday.

A weak front will meander near the waters Friday through early
next week, resulting in somewhat sporadic wind directions.
However, wind speeds should generally be no higher than 15 kt.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 4 AM EDT Friday for AMZ350-352-354-
     374.

&&

NEAR TERM...Adam/JRL
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...JRL
MARINE...Adam/JRL

Hazardous Weather Outlook
National Weather Service Charleston SC
705 PM EDT Thu Jul 20 2023

GAZ087-088-099>101-114>119-137>141-SCZ040-042>045-047>052-212315-
Jenkins-Screven-Candler-Bulloch-Effingham-Tattnall-Evans-
Inland Bryan-Coastal Bryan-Inland Chatham-Coastal Chatham-Long-
Inland Liberty-Coastal Liberty-Inland McIntosh-Coastal McIntosh-
Allendale-Hampton-Inland Colleton-Dorchester-Inland Berkeley-
Inland Jasper-Beaufort-Coastal Colleton-Charleston-Coastal Jasper-
Tidal Berkeley-
705 PM EDT Thu Jul 20 2023

...SEVERE THUNDERSTORM WATCH 529 IN EFFECT UNTIL 1 AM EDT FRIDAY...

This Hazardous Weather Outlook is for southeast Georgia and
southeast South Carolina.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Heat: Heat indices could reach 110 degrees on Friday. Heat
Advisories could be needed.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

AMZ330-350-352-354-212315-
Charleston Harbor-
Waters from South Santee River to Edisto Beach SC out 20 NM-
Waters from Edisto Beach SC to Savannah GA out 20 NM-
Waters from Savannah GA to Altamaha Sound GA out 20 NM, including
Grays Reef National Marine Sanctuary-
705 PM EDT Thu Jul 20 2023

...SEVERE THUNDERSTORM WATCH 529 IN EFFECT UNTIL 1 AM EDT FRIDAY...

This Hazardous Weather Outlook is for Atlantic coastal waters.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

AMZ374-212315-
Waters from Savannah GA to Altamaha Sound GA from 20 to 60 NM-
705 PM EDT Thu Jul 20 2023

This Hazardous Weather Outlook is for Atlantic coastal waters.

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

<!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>