Increasing moisture in the atmosphere Thursday evening will lead to patchy fog across northern Illinois and southern Wisconsin Friday morning. Visibility southeast of Rockford has already fallen to around 5-6 miles in a few locations.
Southerly winds will hold temperatures overnight in the low 20s, with the dew point temperature not too far behind. The lack of snow cover locally will keep dense fog at bay, but visibility down around 3 miles will be possible early in the morning. Any fog that does develop will evaporate, leaving us with a mostly cloudy sky for the afternoon. Highs Friday will warm into the low 40s.