Ross Lazear, a severe weather expert in the University at Albany’s Department of Atmospheric and Environmental Sciences, is available to discuss the spike in tornado activity over the last two weeks across the central U.S.

Here’s his take on the favorable conditions that have resulted in a long period of tornadic thunderstorms: 

“From a large-scale perspective, tornadoes occur when ascending air – often associated with a significant weather system – couples with an unstable air mass and changing winds with height, or wind shear.  A common pattern for a late spring tornado outbreak in the United States is when the jet stream forms a trough — or dip — especially in the western half of the country.  The result is that warm, humid air is transported from the Gulf of Mexico northward, boosting the instability necessary to form strong thunderstorms.  The jet stream also enhances the wind shear, which ultimately is the first source of rotation in a rotating thunderstorm.

Since mid-May, the U.S. has experienced a rather lengthy, stagnant period of weather where the pattern has looked much like this, with strong storm systems developing over the High Plains and ejecting eastward across the Midwest and Ohio Valley.  While it’s not unprecedented to have such a lengthy period of time with this pattern, it has been several years since such an active period of severe weather has taken hold over the country.”

Lazear teaches courses in weather analysis, forecasting, and severe and hazardous weather at UAlbany. He also provides forecasts for the University during major weather events, and has experience observing and forecasting tornadic thunderstorms and hurricanes across the United States.

View his University expert bio to learn more.