A thick blanket of fog covered parts of the Milwaukee area on Oct. 22, leaving even National Weather Service meteorologists puzzled by why the fog was concentrated in such a small area. The worst fog appeared between the Port of Milwaukee and Cudahy, including the area around Milwaukee Mitchell International Airport. The National Weather Service issued a special weather statement at 7:20 p.m. warning that localized dense fog could cause visibility to drop to a quarter mile or less. Some improvement was possible, but the fog could linger into early Friday morning, Oct. 23. Meteorologist Ben Shepard said he and another meteorologist spent about 15 minutes examining possible explanations for why the fog affected that particular area rather than surrounding communities. Shepard said they were equally perplexed. While fog developing near Lake Michigan is not unusual, the highly localized conditions were something Shepard had not encountered in his three and a half years at the weather service. The fog formed as a shallow layer of moist air over Lake Michigan moved inland with light northeast winds, but meteorologists have not determined why the thickest fog remained concentrated in portions of Milwaukee while low clouds extended along the shoreline into Sheboygan County and toward Green Bay. Some locations, including Sheboygan County Memorial Airport, reported reduced visibility, while much of the surrounding region experienced low clouds without fog reaching the ground. The weather service used satellite imagery, Wisconsin Department of Transportation cameras, and airport weather sensors to examine visibility across the region. The fog could linger through the evening of Oct. 22 and into the early morning hours of Oct. 23, although its exact duration and location remain uncertain. Shepard said the fog could shift or dissipate within hours, but meteorologists could not guarantee when conditions would improve. The National Weather Service expects the fog and low level moisture to dissipate within a few hours after sunrise Friday, Oct. 23, as temperatures rise.
