The rush of 300-plus tornadoes in the Southeast this April spread carnage on an order that's difficult to imagine. With nearly 350 fatalities, the epic storms rank as the fourth deadliest U.S. tornado outbreak. Many communities still look fresh from a team of hard-charging wrecking-ball operators.
So, was there anything meteorologists could have done to better prepare for this weather assault?
The folks at NOAA are continually working on that question. To predict severe, tornadic systems of the kind that popped up from April 25 to April 28, one of the things they're looking at is the behavior of lightning as the storms develop. Here's why: Violent supercells that can spawn tornadoes have thick columns of rising air inside their murky boundaries. These powerful updrafts create bursts of lightning in clouds high in the sky, while at the same time cloud-to-ground lightning grows less frequent. By noting this pattern, meteorologists get a good idea of when a storm could drop a twister onto communities below.
One of NOAA's next-generation GOES-R satellites, on target to launch in 2015, will carry a nifty Geostationary Lightning Mapper to sense electric bolts in the clouds and on the ground over the entire United States. For now, meteorologists can use the SPoRT Lightning Mapping Array (part of which is based in Washington, D.C.) to track potentially dangerous systems. Below you can see what the April tornado outbreak looked like through the mechanical eyes of the North Alabama Lightning Mapping Array. The storm that generated the destructive EF-5 tornadoes in Tuscaloosa, Birmingham and Madison, Ala., starts to kick off 40 seconds into the video. Explains NOAA:
The data visualized here are much like those stars, and represent 10,405,546 points that make up thousands of individual lightning bolts from the ground up to an altitude of 9 miles. Each frame of the animation shows all of the measured lightning points in a one minute interval, and the total time span of the animation is 24 hours, starting from 7:00 pm CDT on April 26th. Notice that the large clusters of data points are extremely dense and are located at higher altitudes. These points coincide with observations of almost no lightning ground strikes during severe weather.