Understanding the long-term statistics of environments, properties, and forecast products related to tornadoes (i.e., their climatology) is vital to anchor forecasters assessment and communication of tornado risk. VORTEX-SE/USA research identified an increasing trend in cool season tornadoes in the southeast US, where linear systems are more frequent at night and are more difficult to predict compared to supercell tornadoes that are more prevalent in spring during the day. Likely related, the southeast U.S. was found to have double the nationwide average of annual tornado fatalities.
VORTEX-SE/USA supported development of a nationwide integrated analysis of radar and other data (the MYRORSS project) to facilitate climatological studies of properties of tornadic storms for use by VORTEX-SE/USA researchers and the community at large. Ongoing research using this reanalysis and other VORTEX-SE/USA observations is identifying differences in storm environments between the southeast U.S. and other parts of the country, leading to a better understanding of the regionality to the climatological tornado risk.
Other research shows that tornadoes produced by land-falling tropical cyclones (TCs) are most likely in the right-front quadrant amidst large surface–700-mb bulk wind difference, and the threat increases further inland if a large-scale temperature gradient is present to strengthen the background TC circulation. Operational models being developed to help predict TC hazards (e.g., HWRF and WoFS) show much promise in predicting tornadoes in climatologically correct regions and physical scenarios.
Research adjacent to the tornado problem highlighted important relationships between the parent storm and extreme rainfall, finding nearly twice the amount of rain in the presence of storm-scale to mesoscale rotation.