As of Friday last week we had a couple of storms move through the area and bring snow. It piled up in some places to 14″. Little to now snow was on the ground in parts of western Iowa.
The chart below shows the record setting cold we had at the end of January. Temperatures were below zero for a few days. They finally got above zero on Friday. They continued to warm during the day and at night. There were several hours with the temperature above 40 degrees. The warm and humid air moving over the cold snow cover was the reason for the thick fog all weekend. There are different types of fog based on how they form. The fog we had this weekend is called advection fog.
The fog thinned out this morning as the wind direction turned more to the northwest as cooler and dry air moved into eastern Iowa. You can see how quickly the temperature dropped this morning.
The weather was warm enough for long enough to melt just about all of the snow across Iowa. The map below shows the snow depth at each of those locations. Where some spots had 14″ on Friday they have nothing today.