Picture of the Day

Streamwise vorticity in a supercell thunderstorm

This simulation shows a storm that has spawned a tornado. The scene illustrates how a vortex ring forms when a strong updraft punches into the stable stratosphere, causing the surrounding air to curl downward. Such simulations give researchers insights on the conditions that are likely to herald the development of a tornado. The image compares variables from the dataset of the hypothetical thunderstorm. The plot shows vortex lines--the gold streamlines modeled from vorticity--compared to wind velocity as gray streamlines with red representing highest speed values. In a real storm, you can see the clouds billowing upward and corkscrew striations in the rotating cloud, but the relationship between the wind and rotation isn't exactly clear. Plots like this help to illuminate this relationship, giving a better sense of how the vorticity in the environment is tilted, stretched and intensified in the updraft to make the storm rotate. The image illustrates how vorticity in the environment aligns with the winds feeding into the storm to enhance storm rotation. Improved forecasting and early warning systems have dropped the death toll of tornadoes significantly over the past few decades. But they remain a very real threat to lives and property, especially across the swath of the South-Central U.S. known as "Tornado Alley." Researchers at the University of Oklahoma and the University of Texas at Austin have developed highly-detailed simulations that reveal the complex inner workings of thunderstorms in order to better predict when tornadoes will emerge.

Visit Website | Image credit: Greg Foss, Texas Advanced Computing Center, University of Texas at Austin