(AccuWeather) How do tornado outbreaks occur?
One tornado on its own is enough to devastate a community, but sometimes they spawn in clusters. “Wind shear is the most important ingredient for tornado-producing thunderstorms, and [when] we talk about wind shear, we talk about two factors,” AccuWeather Chief On-Air Meteorologist Bernie Rayno said. Those factors are wind speed and changing wind direction. “Increasing wind speed with height — that adds the energy,” Rayno explained. “The changing wind direction with height is what causes the thunderstorm to rotate, which causes the funnel cloud, which causes the tornado.” Other components needed for a tornado are lift, moisture and instability — all of which must be able to support long-lasting supercells for an outbreak to occur. These conditions are typically found in the central and southeastern U.S., and when they are present over a large area, they can produce a tornado outbreak.
One tornado on its own is enough to devastate a community, but sometimes they spawn in clusters. “Wind shear is the most important ingredient for tornado-producing thunderstorms, and [when] we talk about wind shear, we talk about two factors,” AccuWeather Chief On-Air Meteorologist Bernie Rayno said. Those factors are wind speed and changing wind direction. “Increasing wind speed with height — that adds the energy,” Rayno explained. “The changing wind direction with height is what causes the thunderstorm to rotate, which causes the funnel cloud, which causes the tornado.” Other components needed for a tornado are lift, moisture and instability — all of which must be able to support long-lasting supercells for an outbreak to occur. These conditions are typically found in the central and southeastern U.S., and when they are present over a large area, they can produce a tornado outbreak.
