Dense Fog Advisories are in effect for western parts of Virginia along the Piedmont and into the mountains. This is where dense fog is reducing visibilities to a quarter mile or less. Elsewhere in central Virginia, patchy fog has also developed with some visibilities below a mile to a half-mile. This morning's fog is developing in response to clearing skies, light to calm winds, and ample moisture in and near the ground after several days of rain. Fog will dissipate mid-morning in the region.