Alert archive / Georgia / Mesoscale Discussions in 2020

Mesoscale Discussion 1771

October 29, 20208 counties in Florida; 18 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Oct 29, 2020, 4:16 AM CDT for 8 counties in Florida; 18 counties in Georgia. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: Oct 29, 2020, 4:16 AM CDT (09:16 UTC)
Expired: Oct 29, 2020, 6:15 AM CDT
In force: 119 min
Issued by: the Storm Prediction Center
Concerning: Tornado watch 503

All 26 counties

Bay County, FL, Calhoun County, FL, Gadsden County, FL, Gulf County, FL, Jackson County, FL, Leon County, FL, Liberty County, FL, Wakulla County, FL, Baker County, GA, Calhoun County, GA, Crisp County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Lee County, GA, Miller County, GA, Mitchell County, GA, Randolph County, GA, Seminole County, GA, Sumter County, GA, Terrell County, GA, Thomas County, GA, Turner County, GA, Webster County, GA, Worth County, GA

The radar

The Tallahassee radar (KTLH), 76 km from the middle of the area, began a volume at 09:18 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 00:00Z, 9.3 hours before the alert went out and 77 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 5 J/kg
Mixed-layer CIN: -98 J/kg
Mixed-layer LCL: 1015 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 124 m²/s²
0-3 km storm-relative helicity: 171 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

<!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>

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 28, 11:04 PM CDT	Mesoscale Discussion	SPC	Bay, Calhoun, Gulf, Holmes, Jackson, Okaloosa and 3 more	116 min
Oct 28, 11:34 PM CDT	Tornado Watch	SPC	Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 6 more	7 hr
Oct 29, 2:11 AM CDT	Mesoscale Discussion	SPC	Bay, Calhoun, Gulf, Holmes, Jackson, Liberty and 2 more	94 min

Nearby

Mesoscale Discussions in Georgia, 2020 Mesoscale Discussions in Florida, 2020 Every mesoscale discussion in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.