What is a Severe Thunderstorm?
A severe thunderstorm is a thunderstorm that produces one or more of the following: hail that has a diameter of one inch or larger, winds greater than or equal to 58 mph, and tornadoes. About 10% of all thunderstorms in the U.S. meet severe criteria.
Severe thunderstorms can occur at any time of year, although the most common time of occurrence is during the spring months of March, April, and May.
There is also a lesser known secondary season during the fall, in November and early December.
What is the Difference between a Watch and a Warning?
A severe thunderstorm or tornado watch means that conditions are favorable for severe thunderstorms or tornadoes to develop. These are issued by the Storm Prediction Center in Norman, OK, typically a few hours before severe weather develops.
A severe thunderstorm or tornado warning means that a severe thunderstorm or tornado has either been detected on radar or witnessed by storm spotters firsthand. Your local NWS Forecast Office issues these when severe weather is developing or occurring.
- Have a plan. Prepare ahead of time so you and your family know what actions to take when severe weather occurs.
- Get indoors! There is no safe place outdoors during a thunderstorm.
- Stay informed! When severe weather threatens, stay tuned to NOAA Weather Radio, local television and radio stations, or the National Weather Service webpage at www.weather.gov for up to date information on the weather situation.
- Know what county you are in. When a warning is issued, the threatened area will be identified by the counties that contain it.
- Have a NOAA Weather Radio. This is the best way to receive the latest and most up to date weather information from the National Weather Service.
Information provided by the NWS Nashville Office Severe Weather Awareness Week brochure 2013.