19-05-2025
How Warn-on-Forecast system's data saved lives in Missouri
ST. LOUIS – Warning the public about life-threatening storms is the most important thing we do as meteorologists.
The night of March 14 is one that few in this area will soon forget, as multiple tornadoes touched down that night, leaving swaths of massive destruction in both Missouri and Illinois.
As terrible as that was, it could have been even worse, had it not been for experimental data generated by researchers at the National Severe Storms Laboratory (NSSL) in Norman, Oklahoma. That data is part of a new system under development called Warn-on-Forecast.
'This technology is an ensemble of models. That ensemble is put together in a way that for each individual thunderstorm that's being forecast out to three to six hours in advance, there are probabilities that are computed,' Dr. Pam Heinselman, the NSSL's deputy director of science, said.
For each individual thunderstorm, probabilities are generated for damaging winds, large hail, and even the potential for significant tornadoes, sometimes several hours in advance.
'Something that is unique about this ensemble is we are bringing in new data every 15 minutes,' Heinselman said. 'So, we are cycling into the model the most recent weather radar data, satellite data, other forms of data; re-running the model every half-hour, producing fresh, new forecasts.
'Warn-on-Forecast is a tool in the toolbox that helps to provide heads up to the forecaster.'
The Warn-on-Forecast data is designed to bridge the gap between when the initial watch comes out and the first warnings are issued; a period that can be hours long, with little in the way of information for those who need it most.
'…Somebody who is in charge of an arena, or a concert venue, or a hospital, schools, mobile home parks where somebody has to go somewhere else for safety,' Heinselman said. 'This provides that information ahead of the storm so people can take actions they need.'
And that's exactly what happened the night of March 14!
The Warn-on-Forecast data indicated high probabilities for significant tornadoes, with storms tracking into Carter County. Forecasters shared that information with emergency managers, who passed along the warning to the community.
'So, this community had a heads-up two hours ahead of time (that) there was a high probability for a tornado, and that enabled 120 individuals to take shelter in the community shelter,' Heinselman said. 'Not long after, an EF-3 tornado impacted that area.'
Dr. Heinselman said there is still testing to be done on the system as it works through the demonstration phase of development. But with success stories like March 14, she has high hopes for it to go operational in the future.
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