Alert archive / Tennessee / Dense Fog Advisories in 2021

Dense Fog Advisory 5, NWS Nashville, TN

July 28, 202123 counties in Tennessee

NWS Nashville, TN issued this dense fog advisory at Jul 28, 2021, 2:47 AM CDT for 23 counties in Tennessee. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued: Jul 28, 2021, 2:47 AM CDT (07:47 UTC)
Expired: Jul 28, 2021, 8:00 AM CDT
In force: 5 hr
Issued by: NWS Nashville, TN

All 23 counties

Bedford County, TN, Cannon County, TN, Coffee County, TN, Cumberland County, TN, DeKalb County, TN, Fentress County, TN, Giles County, TN, Grundy County, TN, Hickman County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Marshall County, TN, Maury County, TN, Overton County, TN, Perry County, TN, Pickett County, TN, Putnam County, TN, Rutherford County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, White County, TN

The radar

The Nashville radar (KOHX), 58 km from the middle of the area, began a volume at 07:50 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 00:00Z, 7.8 hours before the alert went out and 290 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: 144 J/kg
Mixed-layer CIN: -238 J/kg
Mixed-layer LCL: 1293 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -24 m²/s²
0-3 km storm-relative helicity: -16 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 Jul 28, 12:13 AM CDT, 2 hours 34 minutes earlier.

Area forecast discussion, Jul 28, 12:13 AM CDT, 2 hours 34 minutes before

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Hazardous weather outlook, Jul 27, 5:24 AM CDT, 21 hours 23 minutes before

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<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>
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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
Jul 28, 2:30 PM CDT	Heat Advisory	OHX	Bedford, Cheatham, Clay, Davidson, Dickson, Giles and 20 more	28 hr

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.