The past week has been incredibly foggy across not only southern Wisconsin but also much of the Midwest. Locally we have had five Dense Fog Advisories issued in the month of January. There are two main culprits for the fog: mild temperatures and light winds. Thanks to the stretch of mild weather, a lot of the snow on the ground has been melting. That creates a lot of extra moisture in the lower parts of our atmosphere. As the melted snow begins to evaporate, that water vapor condenses into the tiny water droplets that create fog. We typically see this happen a lot during the spring. However, we can thank the lack of wind for the persistent foggy conditions. The calm conditions have allowed the fog to stay in place. If we had more of a breeze, that would push the moisture out.
