Beginning Monday, August 2, the National Weather Service (NWS) will be making a change to how information about severe thunderstorms is sent out to the public. NWS will begin adding impact-based warning (IBW) tags to the text of severe thunderstorm warnings, similar to tornado and flash flood warnings.

The NWS developed three categories for severe thunderstorms:

  • A general severe thunderstorm will remain the same as before. A thunderstorm that produces 58 MPH winds and/or 1.00″ diameter (quarter-size) hail will trigger a severe thunderstorm warning from the NWS. The wireless emergency alert system will NOT be activated for thunderstorms of this magnitude.
Criteria for a severe thunderstorm in the United States
  • If a severe thunderstorm strengthens and produces 70-79 MPH winds and/or 1.75″ diameter (golfball-size) hail will be tagged as “considerable“. This will NOT TRIGGER the wireless emergency alert system.
  • A severe thunderstorm will be tagged as “destructive” if it produces 80 MPH winds or greater and/or 2.75″ diameter (baseball size) hail. This WILL ACTIVATE THE WIRELESS EMERGENCY ALERT SYSTEM just like tornado warnings and certain flash flood warnings.

Why Add Severe T-Storms To The WEA System?

The NWS said on its website “the new destructive thunderstorm category conveys to the public urgent action is needed, a life-threatening event is occurring and may cause substantial property damage. Storms categorized as destructive will trigger a WEA to your cell phone”.

Severe thunderstorms can produce tornado-like damage from straight-line winds and/or large destructive hail. All thunderstorms (severe and nonsevere) are dangerous, but the ones tagged as destructive are especially dangerous. To protect yourself and your family, you will want to follow the same precautions as a tornado by moving to the lowest, most interior room of the building you are in.

IMPORTANT: This change will only be for wireless emergency alerts. The NWS will continue to issue severe thunderstorm warnings through its website, NOAA weather radio, Emergency Alert System (EAS), and other platforms. Your mobile weather apps capable of issuing weather warnings (including the NWA Weather Authority app) will still notify you of ALL severe thunderstorm warnings regardless of the damage tag, as long as you have the notifications turned on.

The new severe thunderstorm warning tags will help make sure you and your family are safe when the weather is at its worst.