COLUMBIA —The National Weather Service in St. Louis is tweaking its severe thunderstorm warnings to make it easier for local emergency managers to decide when to sound outdoor warning sirens.
Beginning March 1, the Weather Service will add a tag at the end of severe thunderstorm warnings to specify maximum wind and hail size. The experiment, which runs until Oct. 1, includes Missouri and 13 other states in the Central U.S.
Jim Kramper, a warning coordination meteorologist for the Weather Service, said the additional information is designed to be quickly readable by automated systems that send out weather information and might help local authorities decide when to activate outdoor warning sirens.
"For years, sirens were for nothing but tornadoes,” Kramper said. “But there’s a growing number of communities that turn on sirens for fast wind gusts and hail.”
Zim Schwartze of the Office of Emergency Management in Columbia said the new coding would speed up the process of determining whether sounding outdoor sirens is necessary. That final determination rests with local authorities.
Sirens in Boone County may be sounded if:
- A tornado warning has been issued.
- A severe thunderstorm warning is issued in which extensive damage is probable.
- Reliable information is received that extensive damage has occurred or a funnel cloud was spotted.
- Damaging winds with gusts of over 70 mph.
- The Weather Service issues severe thunderstorm warnings when one or both of these criteria are met:
- Wind gusts of 58 mph or greater.
- Hail 1 inch or larger in diameter.