Dense Fog, Image: NOAA

Dense fog has developed once again across the Northern and Central Plains. Drivers in Oklahoma City, Lincoln, Nebraska and parts of Wisconsin faced dangerous driving conditions this morning.

Dense fog advisories were issued. Advisories come out when fog reduces visibility to 1/4 mile or less over a widespread area. (Source: NOAA)

Fog is a low cloud. In the wintertime, A moist air mass, light wind, and cooling overnight can lead to dense fog.When an air mass cools to its dew point, the air will condense into clouds. This type of fog is called radiation fog. There are many other types of fog that form all year long. The University of Wisconsin has some easy to understand fog descriptions with pictures!

Today's National Forecast, Image: NOAA

Snow is falling once again across the Rockies. Expect a wintry mix in North Dakota and Minnesota, and more rain across the Mid-Atlantic.

-Dawn Brown