Alert archive / Tennessee / Dense Fog Advisories in 2021

Dense Fog Advisory 11, NWS Nashville, TN

December 30, 202138 counties in Tennessee

NWS Nashville, TN issued this dense fog advisory at Dec 30, 2021, 6:21 AM CST for 38 counties in Tennessee. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued: Dec 30, 2021, 6:21 AM CST (12:21 UTC)
Expired: Dec 30, 2021, 9:00 AM CST
In force: 3 hr
Issued by: NWS Nashville, TN

All 38 counties

Bedford County, TN, Cannon County, TN, Cheatham County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, Davidson County, TN, DeKalb County, TN, Dickson County, TN, Fentress County, TN, Giles County, TN, Grundy County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Lawrence County, TN, Lewis County, TN, Macon County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Overton County, TN, Perry County, TN, Pickett County, TN, Putnam County, TN, Robertson County, TN, Rutherford County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, White County, TN, Williamson County, TN, Wilson County, TN

The radar

The Nashville radar (KOHX), 30 km from the middle of the area, began a volume at 12:21 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

Birmingham, AL (KBMX), launched 12:00Z, 0.4 hours before the alert went out and 313 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: 1031 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 644 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 158 m²/s²
0-3 km storm-relative helicity: 146 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 5.7

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this dense fog advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Nashville, TN wrote its last area forecast discussion before this dense fog advisory went out at Dec 30, 5:16 AM CST, 1 hour 5 minutes earlier.

Area forecast discussion, Dec 30, 5:16 AM CST, 1 hour 5 minutes before

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Hazardous weather outlook, Dec 29, 6:44 PM CST, 11 hours 37 minutes before

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In the hours before

Special weather statement, Dec 30, 12:29 AM CST, 5 hours 52 minutes before

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<head>
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  <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.
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The office that day

Everything else NWS Nashville, TN issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 29, 7:02 PM CST	Special Weather Statement	OHX	Grundy	28 min

Nearby

Dense Fog Advisories in Tennessee, 2021 Every dense fog advisory in 2021

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.