Skywarn volunteers are trained by the National Weather Service to detect and report severe local storms.

In 2½-hour courses offered annually around the state, volunteers learn to identify which conditions warrant reporting.

When severe conditions are detected, volunteers relay the information to the weather service by telephone or, in many cases, ham radio.

Skywarn reports allow the weather service to understand images they see on radar, satellite and other technology and to predict trends more accurately.

Although Skywarn spotters can call in weather reports whenever conditions warrant, amateur radio groups will often initiate group network communication sessions, or "nets," during severe weather. The nets are mediated by one person to coordinate the flow of information and report on behalf of all group members.

Although many Skywarn spotters are equipped with computers and miniature home weather stations to aid them in determining wind speeds and other conditions, no special equipment is needed to participate. Volunteers are trained to evaluate conditions by firsthand observation.

Reportable conditions include:

URGENT PRIORITY

Tornado

Funnel cloud

Rotating wall cloud, a type of cloud sometimes associated with tornadoes

Flash flooding

HIGH PRIORITY

Hail ¾ inches in diameter or larger

Wind speed greater than 58 mph

Persistent non-rotating wall cloud

Rainfall of 1 inch or more per hour

LOW PRIORITY

Hail ½ inch in diameter or larger

Wind speed greater than 40 mph

Cloud features suggesting storm organization

Other locally defined criteria.