Alert archive / Wisconsin / Dense Fog Advisories in 2021

Dense Fog Advisory 1, NWS La Crosse, WI

January 2, 202113 counties in Wisconsin; 8 counties in Iowa; 7 counties in Minnesota

NWS La Crosse, WI issued this dense fog advisory at Jan 2, 2021, 1:55 PM CST for 13 counties in Wisconsin; 8 counties in Iowa; 7 counties in Minnesota. It took effect at Jan 2, 2021, 6:00 PM CST. It was in force for 18 hr.

The area

The counties it named.

The facts

Issued: Jan 2, 2021, 1:55 PM CST (19:55 UTC)
In effect from: Jan 2, 2021, 6:00 PM CST
Expired: Jan 3, 2021, 12:00 PM CST
In force: 18 hr
Issued by: NWS La Crosse, WI

All 28 counties

Allamakee County, IA, Chickasaw County, IA, Clayton County, IA, Fayette County, IA, Floyd County, IA, Howard County, IA, Mitchell County, IA, Winneshiek County, IA, Dodge County, MN, Fillmore County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Wabasha County, MN, Winona County, MN, Adams County, WI, Buffalo County, WI, Clark County, WI, Crawford County, WI, Grant County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Monroe County, WI, Richland County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 27 km from the middle of the area, began a volume at 19:52 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, 7.9 hours before the alert went out and 210 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: 1326 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 45 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 La Crosse, WI wrote its last area forecast discussion before this dense fog advisory went out at Jan 2, 11:35 AM CST, 2 hours 20 minutes earlier.

Area forecast discussion, Jan 2, 11:35 AM CST, 2 hours 20 minutes before

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Hazardous weather outlook, Jan 2, 1:39 PM CST, 16 minutes before

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In the hours before

Special weather statement, Jan 2, 10:02 AM CST, 3 hours 53 minutes before

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Nearby

Dense Fog Advisories in Wisconsin, 2021 Dense Fog Advisories in Iowa, 2021 Dense Fog Advisories in Minnesota, 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.