Thick London fog in Sioux Falls

Sioux Falls, SD (KELO-AM) We have to take the good with the bad. Spring-like temperatures helped cause the thick pea soup over a wide area of the Sioux Empire Monday morning.

National Weather Service Forecaster Jeff Chapman in Sioux Falls says "the warmer the air mass is the more moisture can hold."

Morning fog is not unusual in Sioux Falls, but Chapman says this is the densest in a long time. Visibility was down to a quarter-mile or less from the James Valley in Eastern South Dakota all the way to southwestern Minnesota and western Iowa.