What are the weather conditions most likely to cause tornadoes to develop?
Tornadoes develop in environments with plenty of moisture (humidity), instability (the capability for moist air to rise rapidly), and a mechanism that forces or aids the moist unstable air to rise rapidly, e.g. a cold front. But, the key ingredient to aid in tornado formation is wind shear. Wind shear that favors tornado formation is a clockwise change of wind direction with height and an increase in wind speed with height. The clockwise turn in the winds from southeasterly to westerly as you go up in height indicates warm, unstable air flowing into the area. The increase in speed imparts a corkscrew rotation on the storm which, in short, develops the tornado in its lowest levels. Learn more about tornado formation on this USA TODAY resource page. (Answered by Dan McCarthy, warning coordination meteorologist with the Storm Prediction Center in Norman, Okla.
Tornadoes develop in environments with plenty of moisture (humidity), instability (the capability for moist air to rise rapidly), and a mechanism that forces or aids the moist unstable air to rise rapidly, e.g. a cold front. But, the key ingredient to aid in tornado formation is wind shear. Wind shear that favors tornado formation is a clockwise change of wind direction with height and an increase in wind speed with height. The clockwise turn in the winds from southeasterly to westerly as you go up in height indicates warm, unstable air flowing into the area. The increase in speed imparts a corkscrew rotation on the storm which, in short, develops the tornado in its lowest levels. Learn more about tornado formation on this USA TODAY resource page.
