New Severe Thunderstorm Warning Hail Criterion

All National Weather Service offices in the central United States are using an experimental hail criterion for severe thunderstorm warnings this year.  The hail criterion has been raised from 3/4 inch to one inch diameter to reduce the number of warnings for storms that do not cause damage.  The wind criterion remains the same at 58 mph.

Special Weather Statements, which are available on this web site and NOAA Weather Radio broadcasts, will be issued for strong thunderstorms with hail less than one inch diameter and/or wind gusts less than 58 mph. 

Click here to view a short video with more details on the background and implementation of this change.

Questions or comments about this change should be directed to the Rapid City National Weather Service or people may complete an online Customer Survey.


Return to News Archive is the U.S. government's official web portal to all federal, state and local government web resources and services.