Today (April 12) starts Severe Weather Awareness Week in Wisconsin & Minnesota, and the National Weather Services wants the public to learn more about the differences between the various watches and warnings that are issued during the spring and summer months.
A Severe Thunderstorm Watch is issued by the Storm Prediction Center (SPC) when there is a potential for severe thunderstorms to form or move into the area. A severe thunderstorm consists of wind gusts of 58 mph or higher, or 1″ diameter size hail or larger. A Flash Flood Watch is issued when the potential for flash flooding exists. Usually these are issued when abundant, heavy rainfall is expected from thunderstorms, especially if the ground is already near saturation. Flash Flood Watches are sometimes issued if there is a possibility of a dam failure as well. A Tornado Watch is issued by the Storm Prediction Center (SPC) when there is potential for severe thunderstorms that can produce tornadoes. Thunderstorms may be more severe and the atmosphere is favorable for rotation within thunderstorms and tornado development. A Watch is typically in effect for about 6 hours and covers a region of a state.
A Severe Thunderstorm Warning is issued when a thunderstorm is or is expected to produce wind gusts of 58 mph or higher, or 1″ diameter size hail or larger. In this case, either severe weather has been reported or the thunderstorm looks severe based on Doppler Radar. The warning is typically in effect for 30 to 60 minutes and usually covers a county. A Flash Flood Warning is issued when a rapid rise in small creeks and streams is expected. Flash Flooding or mudslides are expected or is occurring. The warning is typically in effect for 2 to 3 hours and covers a county. A Tornado Warning is issued when a severe thunderstorm is or is expected to produce a tornado. In this case, either a tornado has been spotted or rotation is being detected within the thunderstorm on Doppler Radar. The warning is typically in effect for 30 to 60 minutes and usually covers a county. Tornado Warnings are issued infrequently and should be taken very seriously.
Although the statewide tornado drill scheduled for Thursday has been called off, the NWS is still encouraging the public to practice and talk about what would happen in the event of severe weather or a tornado. Some area counties may still sound their sirens on Thursday at 1:45 p.m. and 6:45 p.m. Posts will also be made on social media and some text messages as well. To learn more about Severe Weather Awareness Week, you click here.