A blizzard watch was a bulletin issued by the National Weather Service of the United States which meant winds greater than 35 miles per hour (30 kn; 56 km/h), mixed with falling or blowing snow, and visibilities of 1⁄4 mile (0.4 km) or less is forecast for a period of 3 hours or more. A blizzard watch was issued 12 to 48 hours before an expected blizzard event. As the forecast solidifies, a blizzard watch would be either downgraded to a winter storm warning or winter weather advisory for blowing snow (depending on accumulation amounts) or upgraded to a blizzard warning.