The Verification of the Origins of Rotation in Tornadoes EXperiment-Southeast project, or VORTEX-SE, now VORTEX USA, brings together meteorologists and social scientists for collaboration on a research program. Participants in this project explore the storms and conditions that make tornadoes especially dangerous in the southeastern United States.

The VORTEX-SE project began in 2015 as an effort to understand how environmental factors characteristic of the Southeast affect the formation, intensity, structure, and path of tornadoes in this region. The experiment will also determine the best methods for communicating the forecast uncertainty related to these events to the public.

NO-XP radar in VORTEX SE


For a tornado event of a given magnitude, human casualties are higher in the Southeast than in any other region of the U.S. Researchers believe this is caused by a combination of physical and sociological factors. For example, tornadoes in the Southeast occur in a region often characterized by hills and trees which reduce visibility of the horizon. They are also more likely to occur at night, in fast-moving storms, and earlier in the year compared to other parts of the country. Furthermore, vulnerability is increased by unique socioeconomic factors, which VORTEX-Southeast research has shown include inadequate shelter, housing type, and larger population density relative to other tornado-prone areas in the U.S.

Because of the rate at which technology and scientific knowledge evolve, VORTEX-SE aims to be flexible, quickly adapt to new ways of making observations, and to investigate new ideas in the atmospheric and social sciences.

This is an opportunity to learn more about tornadoes—still poorly understood in any region—and learn how people become aware of their threat and respond in ways that can protect their lives and property.


VORTEX-SE/VORTEX USA has conducted a series of field experiments in the Southeast aimed at developing the capability of making useful scientific observations in this difficult environment. This experience continues informing the plans for major field experiments, like those to be conducted in 2022-2023.

The Propagation, Evolution, and Rotation in Linear Storms experiment, or PERiLS, involves a number of mobile Doppler radars, aircraft, sounding balloons, surface fixed and mobile weather stations, lightning sensors, and profiling instruments, and will be held wherever the conditions look most menacing in Louisiana, Mississippi, Alabama, Arkansas, and western Tennessee. Regions that are relatively open will be utilized because forests interfere with the observations and are dangerous in severe weather. This experiment will make the most detailed observations ever obtained in a tornado field experiment.

Much of the early progress in VORTEX-SE involved research in the social and behavioral sciences. A common emerging theme is that while reliable weather information is often received by individuals and communities, the gains made in improving warning times are being undermined by the limited choices available for taking appropriate sheltering action. Ongoing research and new outreach activities are intended to help individuals and communities understand their best sheltering options, as well as discovering the best time to provide various types of forecast and warning information. This, in turn, will help the meteorologists understand what time periods need the greatest improvement in the quality of the weather information.


NSSL is the lead organization in developing the VORTEX-SE/VORTEX USA research program to meet the VORTEX-SE/VORTEX USA objectives because of NSSL’s experience during the past 25 years in the previous VORTEX experiments. The lab has brought together a number of tornado researchers with expertise in physical science, social and behavioral sciences, and engineering to focus on the most important and urgent areas of research.

Bite-Sized Science: VORTEX-SE in 2018

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