Starting in April, the National Weather Service will be issuing warnings for thunderstorms based on a new set of criteria.  By the old definition, a severe thunderstorm packs winds of at least 58 mph and hail at least 3/4 inch in diameter, or the size of a penny.  This season, a warning will not be issued for hail unless the stones are at least the size of quarters, 1 inch in diameter.

One reason for the change, according to National Weather Service Meteorologist Jeff Lutz, is that very little, if any damage is done by hail smaller than quarter size. 

The change will mean less frequent warnings in many cases.  The new criteria has been tested over the past several years in Kansas and Nebraska.  Emergency managers and media in the test areas say because the warnings are issued less often and are only issued when there is a high risk for damage, it carries more significance for the public.

The NWS is incorporating information about the criteria change into the Storm Spotter Training Classes being held around Northern Michigan this spring.  The classes are free.  A complete schedule can be found here.