HUNTSVILLE, Alabama – Ongoing research at the University of Alabama in Huntsville is uncovering key details about the development of tornadoes, and the work should lead to better forecasting and warnings for those in the path of severe storms.
UAH’s Severe Weather Institute – Radar and Lightning Laboratories (SWIRLL) is the site of a multi-year program focused on storm formation and storm components that lead to tornadoes. SWIRLL, which was commissioned in 2015, is a research facility where students and staff study severe and hazardous weather, radar meteorology, lightning meteorology, lightning physics and air quality.
The Verification of the Origins of Rotation in Tornadoes Experiment Southeast program, known as VORTEX-SE, includes contributions from about 10 universities and scientific agencies, said Dr. Kevin Knupp, professor of atmospheric science at UAH.
“The fundamental goal is to better understand severe storms and in particular tornadic storms and what external factors may play a role,” he said. “As we better understand how these storms work and evolve, we can develop conceptual models for the National Weather Service to use in improving warning accuracy and lead time.”
UAH researchers have published two recent studies related to the program, examining the topography and atmospheric conditions in the Sand Mountain region of northeastern Alabama, which sees an above-average number of tornadoes.
There’s a statistically significant “hot spot” of tornado formation on the Sand Mountain plateau, where there are lower cloud base heights and stronger low-level winds, a mix that tends to support tornadic formation.
The UAH team took an in-depth look at variabilities in temperature and humidity, as well as the influence of wind speed, horizontal shear instability and wind angle on tornado formation.
There is an increase in wind shear on Sand Mountain, especially on the northwestern edge, and the increase is more apparent when we have an environment becoming primed for severe weather,” Knupp said.
However, it’s not as simple as it seems, he said. The shear movement isn’t consistent under all environmental conditions, and the analysis is ongoing.
The VORTEX-SE program recently tracked the long-track EF4 tornado that killed at least 23 people in Lee County in March.
Data from a NEXRAD radar at Maxwell Air Force Base and citizen weather stations were used to reveal a rapidly changing environment that led to that tornado, Knupp said.
While the National Weather Service had good lead time in that storm, Knupp said he hopes additional research can stretch it further, to 30 minutes or more.
“As we look at these rapidly changing environments and the physical processes that produce them, the population should benefit as the lead time is extended,” he said.
Next up for the VORTEX-SE program is a look at non-classical tornadic storms, such as supercells embedded in a background of general rain and squall lines, which are prevalent in the Southeast, Knupp said.
These non-classical storms are marked by a low cloud base and limited visibility. They differ from the highly-visible and isolated classical tornadic storms, which are common in the Great Plains.
Scientific agencies supporting VORTEX-SE include the National Oceanic and Atmospheric Administration and the National Severe Storms Laboratory in Norman, Oklahoma.
Other VORTEX-SE-supported entities conducted social science research, including the University of Alabama, Mississippi State University and the National Center for Atmospheric Research.
Elsewhere in the UA System, students at the University of Alabama are involved in tornado research that tracks how people react to severe weather events.
The project is taking an in-depth look at the vulnerabilities communities face in implementing action plans during such events. UA’s Center for Advanced Public Safety (CAPS) will recruit and train students to interview and observe volunteer households in Tuscaloosa during the fall and spring severe weather seasons.
“There’s never been research on what actually happens in a home when they first become aware of pending weather,” said Dr. Laura Myers, director and senior research scientist at CAPS, who is leading the UA project. “We want to observe how they get weather alerts, what they do when they get it, do they have a plan, when do they enact their plan, when do they think they are safe and what other repercussions occur.”
The work is sponsored by the National Oceanic and Atmospheric Administration and the National Severe Storms Laboratory.
The University of Alabama at Birmingham has also conducted tornado-related research.
Following the devastating April 2011 tornadoes across Alabama, UAB researchers developed lightweight storm-resistant panels, capable of withstanding 250 mph winds, that were installed in homes. The National Storm Shelter Association approved the unique panels to hold up against an EF5 twister.
In addition, scientists at the UAB Injury Control Research Center published research-driven findings suggesting that helmets may prevent injury or death in severe weather situations and should be an essential addition to an individual’s tornado-safety preparations.