Over the past several years, NWS Weather Forecast Offices (WFOs) serving the state of Kansas have experimented with the use of one inch diameter hail as the criterion for a severe thunderstorm as opposed to 3/4 inch diameter hail. The demonstration was such a resounding success among key partners and customers, including emergency management and media, that this policy is being expanded to include all NWS Central Region WFOs. This includes WFO Riverton serving 11 counties of western and central Wyoming.
WFO Riverton will implement this change effective April 1. For those thunderstorms producing hail and wind below severe limits (less than one inch diameter hail or thunderstorm wind less than 58 mph) the "Significant Weather Advisory" will be issued by WFO Riverton under the heading of "Special Weather Statement." Other less significant thunderstorms will be addressed in the Special Weather Statement with an alternative headline. This service remains unchanged from the 2008 severe thunderstorm season.