New Severe Thunderstorm Warning Hail Criterion

The NWS Central Region has expanded the Kansas 1 inch hail Severe Thunderstorm Warning criterion to the entire Central Region of the NWS.  This will include Southeast Michigan and the NWS Detroit/Pontiac office.  The hail criterion for Severe Thunderstorms will change from 3/4 of an inch in diameter to 1 inch in diameter on April 1st.   Background information, including a multi-media presentation, is available on this change.

NWS White Lake will expand the use of the Special Weather Statement (SPS) for storms that produce 3/4 inch hail.  Hazards within the SPS that meet a certain criteria (1/2 inch hail but less than 1 inch, winds 40 mph to 57 mph, and/or frequently lightning) will have a headline "...Significant Weather Advisory/Alert...".  This specific SPS will be called a Significant Weather Advisory/Alert or SWA.

If you have any questions in regards to this change, please feel free to contact:

Richard Pollman, Warning Coordination Meteorologist

(248) 625-3309 x726


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