Jul 02, 2020

Severe Storm Pattern Study May Improve Tornado Warnings

A radar signature may help determine which severe storms are likely to produce dangerous tornadoes


storm water

Scientists analyzed radar data from more than a hundred supercell thunderstorms and found a statistically significant difference in the structure of storms that produced a tornado and those that did not, according to Science Daily.

Though tornado warning times have improved over the last several decades, decision-makers often must rely on readily available information like radar data when issuing storm warnings. 

"Identifying which storms are going to produce tornadoes and which are not has been a problem meteorologists have been trying to tackle for decades," said Scott Loeffler, a graduate student in the Department of Meteorology and Atmospheric Science at Penn State. "This new research may give forecasters another tool in their toolbox to do just that."

In 2013, the U.S. upgraded its radar network to include polarimetric capabilities, which provide additional information about storms, including revealing shape and size of raindrops, reported the researchers.

With this information, scientists compared areas with large, sparse raindrops and regions dense with smaller drops within supercell storms. 

"We found for nontornadic supercells, the orientation of the separation between these two areas tended to be more parallel to the direction of the storm's motion," Loeffler said. "And for tornadic supercells, the separation tended to be more perpendicular. So we saw this shift in the angles, and we saw this as a consistent trend."

The algorithm from the study can easily be adapted so operational forecasters could use the program in real time with the latest radar data available, added Loeffler. "Many factors go into issuing a tornado warning, but perhaps knowing the orientation in real time could help them make a decision to pull the trigger or to hold off.”

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