Special Weather Statement issued October 21 at 9:27PM EDT by NWS

…PATCHY DENSE FOG WILL DEVELOP OVERNIGHT WITHIN PORTIONS OF THE HUDSON RIVER VALLEY AND ADJACENT CONNECTICUT RIVER VALLEY… Patchy dense fog will continue to develop within the Hudson River Valley in eastern New York, and Connecticut River Valley in southeast Vermont overnight. Some visibilities will drop under one half of a mile.

Source: National Weather Service Alerts for Vermont