IEM Daily Feature
Friday, 27 March 2009

One Inch Hail

Posted: 27 Mar 2009 05:59 AM


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Based on warnings issued by Davenport, La Crosse, Sioux Falls, Omaha, and Des Moines not just for Iowa.
On April 1st, National Weather Service Offices in the Central Region will be changing its severe weather warning criteria for hail size to one inch and larger (previously was penny sized 0.75). Some details behind the reason for this change can be found with this NWS webinar. The featured pie charts attempt to look forward to one probable outcome of this change, a decrease in the number of warnings. Of the 2200 warnings issued in the past two years, 24% of them were verified by only hail stones that would no longer justify a warning. The lower pie chart details the initial justification for issuing the warning based on product text. Please note the warning may have included a justifcation of damaging wind as well as hail, but this analysis only worries about what hail size was included. Half of the warnings issued mentioned hail sizes that will no longer be severe, again there may have been damaging winds mentioned in those as well.

Voting:
Good = 36
Bad = 18

Tags:   hail   nws