Weather Service Aims to Improve Storm Warning Precision

As tornado season begins in the Tennessee Valley, the National Weather Service is implementing a warning system designed to give more specific information on approaching storms.

Piloted last year in the Midwest, the Huntsville weather office is adding “impact-based warnings” to its storm notifications. Meteorologist Stephen Latimer said the warnings will describe whether a tornado is damaging or deadly.

“We’re trying to make it easier for folks to know what to expect in terms of impact,” Latimer said. “We will still use the polygram on our maps to show the potential impact areas.”

The new warning information includes two levels: hazard possibilities and enhanced damage possibilities. A meteorologist can state the hazard options of hail, damaging winds, tornado, damaging tornado and deadly tornado. It also shows if the radar and/or storm spotters are seeing a tornado while describing the level of damage.

Latimer said the addition doesn’t change the weather service’s use of the watch or warning, which used to be the only information given. Meteorologists also will continue to use the familiar enhanced Fujita tornado scale to measure a tornado’s strength. The EF scale is usually used after meteorologists can study the damage path.

The weather service made the change because it found residents often depend on storm sirens for notice and then seek more information from alternate sources, such as newspaper websites, TV and radio, Latimer said.

“We want to give the residents and the media more information,” he said.

Rita White, director of the Limestone County Emergency Management Agency, has dealt with tornado disasters in three of the past four years.

She said the additional information, particularly about whether a tornado has been spotted by radar and/or a storm spotter, will be helpful for first responders and her agency.

“Radar can’t tell if a tornado is on the ground unless there’s a debris field,” White said. “A spotter can see one that’s on the ground, but he can’t see that there’s one approaching from a long distance away. This just helps us know what the real situation is.”

White’s job is to prepare daily for the possibility of disaster. One area of focus in the past year has been building storm shelters in Limestone County.

Storm shelters were why officials said only two people died in the April 28, 2014, tornado disaster that hit western Limestone County and Athens.

Using state and federal grants, the Limestone County Commission built shelters in Tanner, Elkmont and Oak Grove.

A 168-person shelter on Cowford Road in Tanner was finished this week.

The county will have 12 storm shelters when a shelter on Settle Road in Pine Ridge is complete. Crews must install a septic tank and finish landscaping before it opens.