Alert archive / South Dakota / Dense Fog Advisories in 2021

Dense Fog Advisory 5, NWS Sioux Falls, SD

January 8, 202116 counties in South Dakota; 7 counties in Iowa; 8 counties in Minnesota

NWS Sioux Falls, SD issued this dense fog advisory at Jan 8, 2021, 2:30 PM CST for 16 counties in South Dakota; 7 counties in Iowa; 8 counties in Minnesota. It took effect at Jan 8, 2021, 7:00 PM CST. It was in force for 17 hr.

The area

The counties it named.

The facts

Issued: Jan 8, 2021, 2:30 PM CST (20:30 UTC)
In effect from: Jan 8, 2021, 7:00 PM CST
Expired: Jan 9, 2021, 12:00 PM CST
In force: 17 hr
Issued by: NWS Sioux Falls, SD

All 31 counties

Cherokee County, IA, Clay County, IA, Dickinson County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Sioux County, IA, Cottonwood County, MN, Jackson County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Aurora County, SD, Beadle County, SD, Bon Homme County, SD, Brookings County, SD, Brule County, SD, Charles Mix County, SD, Davison County, SD, Douglas County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, Miner County, SD, Moody County, SD, Sanborn County, SD

The radar

The Sioux Falls radar (KFSD), 18 km from the middle of the area, began a volume at 20:30 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

Minneapolis, MN (KMPX), launched 12:00Z, 8.5 hours before the alert went out and 289 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 855 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: -44 m²/s²
0-3 km storm-relative helicity: -14 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 Sioux Falls, SD wrote its last area forecast discussion before this dense fog advisory went out at Jan 7, 5:11 PM CST, 21 hours 19 minutes earlier.

Area forecast discussion, Jan 7, 5:11 PM CST, 21 hours 19 minutes before

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Hazardous weather outlook, Jan 7, 5:21 PM CST, 21 hours 9 minutes before

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      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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Nearby

Dense Fog Advisories in South Dakota, 2021 Dense Fog Advisories in Minnesota, 2021 Dense Fog Advisories in Iowa, 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.