Definitions and Terminology
Severe local storms occur in all parts of the continental United States in an average year. As part of their training, storm spotters are aware of severe storm definitions and terminology used by the National Weather Service. Some of the more common terms utilized are detailed below
Watch — Conditions are favorable for the severe weather event in or near the watch area. Watches are issued for tornadoes, severe thunderstorms, and flash floods.
Warning — The severe weather event is imminent or occurring in the warned area. Warnings are issued for tornadoes, severe thunderstorms, flash floods, and river flooding.
Severe Thunderstorm — A storm that produces hail 3/4 inch in diameter or larger and/or wind gusts of 58 mph or more.
Tornado — A violently rotating column of air attached to a thunderstorm and in contact with the ground.
Funnel Cloud — A rotating, funnel-shaped cloud extending downward from a thunderstorm base.
Downburst — A strong downdraft with an out rush of damaging wind on or near the ground.
Flash Flood — A rapid rise in water, usually within 12 hours of a period of heavy rain or other causative agent (i.e., dam break).
Winter Storm Watch
A "WATCH" is a long range prediction. They are issued at least 12 hours before the hazardous winter weather is expected to begin. A Winter Storm Outlook may be issued before a Watch (normally in the 2 to 5 day time period).
Issued when there is the potential for hazardous winter weather due to various elements:
Heavy snow or heavy lake effect snow. In our region, heavy snow means 7 inches or more of accumulation in 12 hours or less, or 9 inches or more of accumulation in 24 hours or less.
A significant, and possibly damaging accumulation of ice (normally at or greater than 1/2 inch).
Blizzard conditions.Heavy mixed precipitation (snow, sleet and freezing rain), blowing and drifting snow, etc.
Winter weather causing significant public impact even if the above criteria is not met.
Winter Storm Warning
A "WARNING" is issued when conditions become imminent, or have a high probability of occurring.
Issued when the following winter weather conditions become imminent or have a high probability of occurring:
Heavy snow or heavy lake effect snow. In our region, heavy snow means 7 inches or more of accumulation in 12 hours or less, or 9 inches or more of accumulation in 24 hours or less.
A significant, and possibly damaging accumulation of ice (normally at or greater than 1/2 inch).
Blizzard conditions.Heavy mixed precipitation (snow, sleet and freezing rain), blowing and drifting snow, etc.
Winter weather causing significant public impact even if the above criteria is not met.