Dense Fog in Wisconsin, September 20 to 21, 2007

Name: Dense Fog in Wisconsin, September 20 to 21, 2007
Start: 2007-09-20T18:00
End: 2007-09-21T01:00
Location: Wisconsin

September 20 to 21, 2007 · NWS MKX · 8 events in 8 counties and zones

Dense fog affected parts of east-central and southeast Wisconsin during the overnight hours and lowered visibilities to 1/8 to 1/4 mile. Several airplane flights were delayed or cancelled.

Where it happened

Every event with a place to put it; 8 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 8

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.

Dense fog affected parts of east-central and southeast Wisconsin during the overnight hours and lowered visibilities to 1/8 to 1/4 mile. Several airplane flights were delayed or cancelled. The dense fog was actually leftover dense fog that had persisted over the nearshore waters of Lake Michigan from the early morning hours of September 20th. A light southeast wind during the daytime hours transported the leftover dense fog inland. Clear skies and radiational cooling allowed the dense fog to expand as it moved inland.

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 Sep 20, 4:50 PM CST, 1 hour 10 minutes earlier.

Area forecast discussion, Sep 20, 4:50 PM CST, 1 hour 10 minutes before

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Hazardous weather outlook, Sep 20, 4:15 PM CST, 1 hour 45 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

8 dense fog. Local standard time, as filed.

Dense Fog, Fond du Lac

When: September 20, 6:00 PM CST to September 21, 1:00 AM CST
Where: Fond du Lac forecast zone
Reported by: ASOS
Coordinates: 43.754, -88.488 (the zone’s center; the record gives no point)

Dense Fog, Sheboygan

When: September 20, 6:00 PM CST to September 21, 1:00 AM CST
Where: Sheboygan forecast zone
Reported by: ASOS
Coordinates: 43.756, -87.800 (the zone’s center; the record gives no point)

Dense Fog, Washington

When: September 20, 6:00 PM CST to September 21, 1:00 AM CST
Where: Washington forecast zone
Reported by: ASOS
Coordinates: 43.369, -88.231 (the zone’s center; the record gives no point)

Dense Fog, Ozaukee

When: September 20, 6:00 PM CST to September 21, 1:00 AM CST
Where: Ozaukee forecast zone
Reported by: ASOS
Coordinates: 43.403, -87.891 (the zone’s center; the record gives no point)

Dense Fog, Waukesha

When: September 20, 6:00 PM CST to September 21, 1:00 AM CST
Where: Waukesha forecast zone
Reported by: ASOS
Coordinates: 43.018, -88.304 (the zone’s center; the record gives no point)

Dense Fog, Milwaukee

When: September 20, 6:00 PM CST to September 21, 1:00 AM CST
Where: Milwaukee forecast zone
Reported by: ASOS
Coordinates: 43.022, -87.929 (the zone’s center; the record gives no point)

Dense Fog, Racine

When: September 20, 6:00 PM CST to September 21, 1:00 AM CST
Where: Racine forecast zone
Reported by: ASOS
Coordinates: 42.730, -87.812 (the zone’s center; the record gives no point)

Dense Fog, Kenosha

When: September 20, 6:00 PM CST to September 21, 1:00 AM CST
Where: Kenosha forecast zone
Reported by: ASOS
Coordinates: 42.573, -87.840 (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 2007 Every state in 2007 This day in weather history Warnings in Wisconsin, September 2007

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: 61094, 61095, 61096, 61097, 61098, 61099, 61100, 61101.