Dense Fog in Wisconsin, January 23, 2012

Name: Dense Fog in Wisconsin, January 23, 2012
Start: 2012-01-23T02:30
End: 2012-01-23T09:00
Location: Wisconsin

January 23, 2012 · NWS MKX · 3 events in 3 counties and zones

light winds and a cool air mass accompanying a low pressure led to the formation of dense fog over far southern sections of South-central Wisconsin. The dense fog reduced visibilities to 1/4 mile or less.

Where it happened

Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 3

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS MKX wrote it up.

Abundant low-level moisture...light winds and a cool air mass accompanying a low pressure led to the formation of dense fog over far southern sections of South-central Wisconsin. The dense fog reduced visibilities to 1/4 mile or less. Aloft, a negatively-tilted mid-level short-wave trough crossed southern Wisconsin during the overnight and early daylight hours of January 23rd.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Milwaukee, WI wrote its last area forecast discussion before the first event at Jan 22, 3:11 PM CST, 11 hours 19 minutes earlier.

Area forecast discussion, Jan 22, 3:11 PM CST, 11 hours 19 minutes before

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Hazardous weather outlook, Jan 22, 3:39 PM CST, 10 hours 51 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 dense fog. Local standard time, as filed.

Dense Fog, Lafayette

When: January 23, 2:30 AM CST to 7:00 AM CST
Where: Lafayette forecast zone
Reported by: Law Enforcement
Coordinates: 42.661, -90.132 (the zone’s center; the record gives no point)

Dense Fog, Green

When: January 23, 2:30 AM CST to 9:00 AM CST
Where: Green forecast zone
Reported by: AWOS
Coordinates: 42.680, -89.602 (the zone’s center; the record gives no point)

Dense Fog, Rock

When: January 23, 2:30 AM CST to 9:00 AM CST
Where: Rock forecast zone
Reported by: AWOS
Coordinates: 42.671, -89.072 (the zone’s center; the record gives no point)

What these are

Dense Fog: Fog reducing visibility to a quarter mile or less, filed where it caused accidents or disruption.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Wisconsin in 2012 Every state in 2012 This day in weather history Warnings in Wisconsin, January 2012

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 362574, 362575, 362576.