Moving tornado warnings: How Threats-in-Motion may evolve the way we communicate severe weather

The current process to create warnings involves a forecaster making a judgment about a severe weather threat at a single point in time, issuing a warning polygon, and then issuing more warnings downstream if a storm maintains its intensity as it moves along. The effect is a string of independent warnings, all for a single storm, that can leave people living just outside and downstream of the warning at a distinct disadvantage; in particular, they might experience very brief lead times when they finally are warned, even when the forecaster anticipates that a storm will maintain its strength. The current system does not serve these individuals equitably, and it also fails to convey the fullness of forecaster thinking as a storm moves. Threats-in-Motion (TIM) aims to resolve this inequity of service by replacing this technique with a more modern process that allows the forecaster to issue and maintain a severe thunderstorm or tornado warning that follows the storm.

Over the last eight years, the National Severe Storms Lab has worked closely with partners at the Global Systems Lab, National Weather Service, emergency management, and broadcast media to iteratively test and evaluate more rapidly updating severe thunderstorm and tornado warnings. This presentation will highlight ongoing, as well as future directions, for Threats-in-Motion warnings.