Skies remained mostly cloudy through most of Wednesday morning following dense fog for some. Drier air moving in early afternoon allowed the cloud cover to break, bringing temperatures into the middle and upper 60s. As of 4pm, Rockford’s current temperature was 70 degrees.

Skies will continue to clear with high pressure moving south through the evening. This will allow overnight lows to dip into the upper 40s once again. With clear skies and light winds areas of fog are likely to develop once again, becoming dense for some around sunrise Thursday morning. Be careful on the morning drive Thursday.

This type of fog is known as ‘radiation fog’ and develops as a result of a few things: light to calm winds, clear skies, and low-level moisture. Radiation fog is very common here in the Stateline, occurring often during the fall and winter months. As the air temperature cools during the evening and overnight it begins to stabilize. As the air temperature falls closer to the dew point temperature it reaches saturation, allowing fog to form. Fog develops first near the surface, thickening as the air cools, before extending upward through the night.

As the sun comes up the next morning temperatures warm, causing the fog to clear (most of the time). We’ll see fog again Wednesday night, but a little more of a breeze and warming temperatures should limit fog development through the rest of the week.