Alert archive / Tennessee / Dense Fog Advisories in 2021

Dense Fog Advisory 12, NWS Nashville, TN

December 30, 202125 counties in Tennessee

NWS Nashville, TN issued this dense fog advisory at Dec 30, 2021, 7:50 PM CST for 25 counties in Tennessee. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued: Dec 30, 2021, 7:50 PM CST (01:50 UTC)
Expired: Dec 31, 2021, 2:56 AM CST
In force: 7 hr
Issued by: NWS Nashville, TN

All 25 counties

Bedford County, TN, Cannon County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, DeKalb County, TN, Fentress County, TN, Giles County, TN, Grundy County, TN, Jackson County, TN, Lawrence County, TN, Macon County, TN, Marshall County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Rutherford County, TN, Smith County, TN, Sumner County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, White County, TN, Wilson County, TN

The radar

The Nashville radar (KOHX), 61 km from the middle of the area, began a volume at 01:48 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

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 1.8 hours before the alert went out and 317 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: 17 J/kg
Mixed-layer CIN: -151 J/kg
Mixed-layer LCL: 958 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 83 m²/s²
0-3 km storm-relative helicity: 177 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

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, 6:55 PM CST, 55 minutes earlier.

Area forecast discussion, Dec 30, 6:55 PM CST, 55 minutes before

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Hazardous weather outlook, Dec 30, 6:17 PM CST, 1 hour 33 minutes before

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  <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.
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        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 31, 8:31 AM CST	Special Weather Statement	OHX	DeKalb	44 min
Dec 31, 9:14 AM CST	Special Weather Statement	OHX	Overton, Putnam	46 min
Dec 31, 9:31 AM CST	Special Weather Statement	OHX	Montgomery	44 min
Dec 31, 10:09 AM CST	Special Weather Statement	OHX	Robertson	51 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.