A University of Nebraska–Lincoln team has received funding from the National Science Foundation to execute a model-based study into how severe storms are formed across the Great Plains.
The project’s goal is to improve storm predictions by assessing their potential strength and gauging the chance for tornadoes or flash floods.
Steve Hu, professor of natural resources and of Earth and atmospheric sciences, received a $200,000 grant for the two-year study. Hu will work with a team of graduate students to understand how a certain group of nocturnal convection and natural storms develop.
“There are storms ― particularly during the warm season in the Great Plains — that develop just purely by themselves, from nowhere,” Hu said.
Hu became curious about these storms after learning about a study done by Oklahoma researchers which found that one-third of storms are formed without the presence of a front. Prior to that study, researchers believed that most storms were formed because of a front — a boundary separating two masses of air of different densities.
“So, we are trying to understand the mechanism or mechanisms that cause the initiation and development of this one-third of mostly nocturnal storms in the Great Plains during the growing season,” he said.
Using his background in convection and mechanics, Hu has hypothesized that in the summer, a strong and moisture-filled southern jet comes up from the Gulf of Mexico. According to the hypothesis, that jet starts to twist and bend to the east due to the Earth’s rotation, causing a vortex with a northern axis. From the west, a flow coming off the Rockies adds another current to the mix. The Great Plains sit right under this crash of winds.
Once the vortex is formed, Hu said, it may get stronger in the night, when there’s no rising, warm air to slow it down. That strength could help lift the air around it, causing convection and storms.
One of Hu’s graduate students, George Limbert, is using a simple model to look for convection. In initial testing this summer, the researchers have seen the phenomenon occur.
“His initial results have shown promising signs that, yes, there is an uprising motion on the eastern side of this northern vortex,” Hu said.
Hu now plans to use a more complicated and realistic model that accounts for many other factors to test for convection. If the team’s data shows the mechanics occurring, Hu would like to compare actual storm data with the model to see if it’s correct.
“The point of all of this is predicting,” Hu said.