After last week's rains, there is still ample low-level moisture to serve as "fuel for fog" this Tuesday morning. We had clear skies overnight with lighter winds, as well, and that allowed patchy fog to develop in spots. Where fog has developed, it has become dense, with visibilities being reduced below a half-mile in many places, especially south of I-64 from Richmond, and south of Petersburg into North Carolina. As of 6 a.m., the visibility at Emporia and South Hill is just a quarter of a mile. I expect the fog to last through sunrise, and for the spots where it is dense, it may take until mid-morning to fully lift.