HUNTSVILLE, Ala. (WHNT) — Roughly 200 tornadoes devastated the Southeast from early morning to evening on April 27, 2011.
It was a historical event, one characterized by intense lines of storms and supercells, or rotating thunderstorms. That day affected many in the Tennessee Valley in different ways. Some of those who were kids at the time and now study meteorology at the University of Alabama – Huntsville (UAH), say that that day made them want to become a meteorologist.
After the outbreak, the state of Alabama received a grant, allowing the Severe Weather Institute -Radar and Lightning Laboratories (SWIRLL) to be built.
The ribbon-cutting of the building was in 2014 but the building opened to researchers in the spring of 2015. This building was built as a research facility where students can study all types of weather from winter storms to severe thunderstorms.
In the years since April 2011, students and professors have participated in field campaigns where they take their instruments into the field and study severe storms in real-time. One of the campaigns, called VORTEX-SE (Southeast), focused on how severe storms behave in the Southeast.
Their research followed the differences in severe storms in the Southeast versus the Great Plains, where many tornadoes occur in the spring. Storms in our part of the country tend to form in environments with lower instability and high wind shear. Wind shear is a change in the wind with height. Directional shear is a change in the wind direction with height. Speed shear is an increase in the wind with height. High wind shear can lead to a greater tornado threat.
“The day to night variability during the cool season is less pronounced,” says Dr. Kevin Knupp, professor of Atmospheric Science at UAH. “So we can have tornadoes any time of the day and any month of the year -and that’s really unique to the Southeast.”
Knupp says their research is also focused on the environment around the storms. He says that rain doesn’t necessarily lead to a stable atmosphere. In some cases, it can enhance the tornado threat.
Preston Pangle, a graduate student and SWIRLL research associate, has been studying severe storms over the years. He says they use several different mobile instruments to help them track storms and their environment.
One of those instruments is a mobile radar, a vehicle they call “MIPS” that includes a wind profiler and vertical radar that can shoot radar beams directly up into a storm’s environment versus using a full-circle scan. MIPS also houses the control center where researchers can watch data come in in real-time.
Another vehicle they call “M3V” has several instruments on its roof that can measure things like temperature, wind and humidity.
Their new field campaign called “PERILS” is an effort to study tornadoes in lines of thunderstorms, called squall lines. These types of storms are more common in our region. What they’ve found so far is small-scale features can interact with these storm lines and lead to tornadoes.
Knupp says it’s important to be able to identify these small-scale features to better warn of tornadoes.
PERILS will end on May 1, 2022, but will pick back up again in February 2023.