Central US looks forward to sunshine after week-long fog lifts
Barchart · 01/29 10:50

Central U.S. cities are soaking up the sun after some, including St. Louis, Chicago and Tulsa, went about a week in pea soup fog thanks to warmer temperatures creating dense fog across the region. 

St. Louis last saw the sun a week ago, this Sunday. Sunlight finally started to break through the clouds at the end of the weekend, with more abundant sunshine on Monday.

The gloom isn't entirely done yet.

Dense Fog Advisories are in effect through Monday morning for central Minnesota, including the Twin Cities. Fog alerts are in place through Monday morning in north central Wisconsin, including Iowa, Chickasaw, Clayton, Fayette, Howard and Winneshiek counties.

Visibility could be a quarter mile or less, making driving conditions dangerous for the Monday morning commute. 

WHAT IS FREEZING FOG?

This week's fog will pale compared to the record-setting fog last week when the National Weather Service issued dense fog advisories for 20 states, covering more than 30% of the country. 

A warmer weather pattern brought higher temperatures across the country's center last week after January’s deadly arctic blast

After nearly two weeks of subfreezing temperatures, the ground remained cold while a very moist air mass on top of the cold ground caused dense fog to form.

"That fog is acting as a blanket," said FOX Weather Meteorologist Stephen Morgan. "Any sort of heating that we get throughout the day - not so much from the sun, but just from the mixing of the atmosphere. Because that warmth is spread through the mid-levels, and then it mixes down at the surface."

The pea-souper continued north into Canada, where dense fog covered the skyline in Winnipeg.

WHAT IS SUPER FOG AND WHAT CAUSES IT?

After waiting days for the sun, it finally appeared in Norman, Oklahoma, just ahead of an appearance in Tulsa.

The National Weather Service offices in St. Louis and Chicago also forecast a glimpse of the sun to reappear this week before another cold front moves in with cloud cover.