The nation’s largest fog machine? That would be Lake Michigan, at least for tonight. An expansive area of dense fog that’s been sitting over the southern end of the lake all day is starting to work its way onshore.
The fog is a by-product of moist air (dew point temperatures in the lower 60s) interacting with lake cooled air. As moist air drifts over the lake, it is cooled to the saturation point, which results in low level cloud or fog formation that hugs the surface. Another key ingredient for lake fog in this instance is light winds. Lake water temperatures are still on the chilly side, ranging from 48 degrees thirty miles offshore, to 61 degrees at Oak Street Beach.
Due to calm winds overnight, the fog is expected to persist until Tuesday morning. Inland locations may also experience some fog overnight.
BELOW: A Dense Fog Advisory continues for lakeshore communities in Cook, Lake(IL), Lake(IN), Porter and La Porte counties until 9AM Tuesday. Visibility will vary from 3 miles to 1/8th of a mile, and could drop to 100 feet or less at times near the Lake Michigan shoreline.
BELOW: A 40 mile wide blanket of dense fog that’s been sitting over the southern end of Lake Michigan all day continues to move onshore this evening.