NWS Grand Junction Moving to New Hail Criterion for Severe Thunderstorms on April 1
During the past several years, NWS Forecast Offices serving the state of Kansas have experimented using one-inch diameter hail criterion for the Severe Thunderstorm Warning (SVR) product as opposed to the long-used ¾ inch diameter criterion. The demonstration was considered a resounding success by the general public and key partners, including emergency managers and media. Therefore, the new one-inch diameter hail criterion is being expanded to gradually include all states within the continental USA.
In Colorado, the switch to the new one-inch diameter hail criterion will occur on April 1st of this year. In Utah, the switch is planned for June 1st of this year.
For thunderstorms that produce or are expected to produce hail and/or wind below SVR criteria (less than one-inch diameter hail and/or less than 58 mph winds), a new product will be issued if the hail or wind is considered to be significant. That new product is called the “Significant Weather Advisory” and will only apply to thunderstorms that produce significant hail and/or wind below SVR criteria. The “Significant Weather Advisory” will be issued under the “Special Weather Statement” category.
For more information about this change of hail criterion for Severe Thunderstorm Warnings, please watch the informational video. Return to News Archive