The process of forecasting a warning begins days ahead of time, when the threat area is determined. Hazardous weather outlooks are issued early every morning and updated as conditions warrant.
Watches are issued when conditions are favorable for tornadoes, severe thunderstorms or flash floods. If you are in an area that is under a watch alert, continue with normal activities but make plans to seek shelter if necessary. When the National Weather Service issues a weather watch, TV and radio stations pass the information on to the public.
Thunderstorms are severe storms that can produce hail, heavy rain, frequent lightening, wind speeds greater than 57 miles per hour or straight-line winds that can exceed 100 miles per hour. Some thunderstorms also produce tornados. In Minnesota, thunderstorms typically occur in the spring, summer and fall lasting an average of 30 minutes. A severe thunderstorm watch means the current weather conditions can cause a thunderstorm to develop in the area.
Tornados are violent, dangerous windstorms that typically form a funnel-shape but can take on many shapes and sizes. They're usually spawned by thunderstorms. Tornados usually occur between March and August in Minnesota, although they can occur at any time of the year. A tornado watch means the current weather conditions can cause a tornado to develop in the area.
Warnings are issued when severe weather has been reported or is imminent. Seek shelter immediately if you are in or near the path of the storm. Know the name of the county you live in and the cities around you; warnings are issued by county names, city names, and well-known landmarks. Warnings are disseminated swiftly and updated frequently until the threat has ended.
A severe thunderstorm warning means a thunderstorm has been indicated on radar for a specific area. An outdoor warning siren may be activated. Take shelter immediately and listen for emergency information on a radio or TV.
A tornado warning means a tornado has been spotted or is strongly indicated on radar in a specific area. An outdoor warning siren will be activated. Take shelter immediately and listen for emergency information on a radio or TV.