Winter Storm Watch: Decent confidence that a winter storm will develop and produce heavy snow, sleet or freezing rain. A watch means to be prepared. In the Miami Valley, the criteria for a watch is 6 inches of snow or ½ inch of sleet in 12 hours; or 8 inches of snow in 24 hours. These will be issued a few days out.
Winter Storm Warning: Significant winter weather including heavy snow, sleet, freezing rain, blowing snow or a combo is expected to affect the area. Travel will be dangerous. The Winter Storm Watch criteria listed above will be possible but the window that it is expected to start is smaller, usually a day or less away from the event. Warning means you should take action and be ready for deteriorating travel.