What's the difference between a tornado and severe thunderstorm warning?

 The National Weather Service issues many different type of warnings, including severe thunderstorm and tornado warnings. Both of which cause damage but have many differences in extent of damage. Most thunderstorms do not do much damage, but once you get closer to 60+ mph winds, larger limbs can be broken, and small trees can be uprooted. Above 80 mph is when structural damage is possible if not likely.

Once you get up toward 60-80 mph, that is equivalent to a weak tornado. An EF0 tornado ranges from 65-85 mph, while EF1 is when winds reach 86-110 mph. While the most destructive tornadoes do much more damage, those are very rare. Only around 5% of all tornadoes reach EF3 intensity or greater.

The damage paths of tornadoes vary greatly from straight line winds as well. A swath of straight-line winds can be around 5 miles wide, stretching across the core of the thunderstorm itself. Tornado damage may be confined to a much narrower area, as even larger tornadoes may only be a mile at their widest. That means the damage paths may be much more widespread from severe straight-line winds than tornadic storms.

Severe thunderstorm warnings from the National Weather Service can fall into one of three categories: Base, Considerable, or Destructive. A Base severe thunderstorm is for winds of 58+ mph and/or quarter sized hail. Considerable would indicate 70+ mph wind gusts and/or golf ball sized hail are possible. And a Destructive tag is for a severe thunderstorm capable of producing 80+ mph wind gusts and/or baseball sized hail. A Destructive severe thunderstorm will trigger the wireless emergency alerts (WEA) on your cell phone, like all tornado warnings do regardless of strength.

A "tornado possible" tag is also utilized within a severe thunderstorm warning when there is broad rotation, conditions favorable for rotation, or the storm has had a history of producing tornadoes. That "tornado possible" tag is a way to alert the public that a quick spin-up tornado can occur but is not imminent at that time.

You will often hear our weather team say "treat this severe thunderstorm warning as if it were a tornado warning." That is partly because of the larger coverage of damage than can be done, but also because the intensity of some severe storms can be equivalent to that of a weak tornado. Severe thunderstorm warnings will NOT automatically trigger your cell phone unless they reach 80 mph winds.

This is why it is important to have many ways to receive those warnings. Weather apps on your phone, including the "First Warn Weather App", can send push notifications for all severe thunderstorm warnings. Weather radios will broadcast warnings, watches, and other important weather information. Simply relying on your phone and tornado sirens will not alert you for all hazardous weather.

Hopefully this article has given some context behind why some storms have tornado warnings and others don't, the strength of some severe storms, and additional resources you can remain weather aware and stay safe during the storm season and the rest of the year.