Across in the States the tornado season has fired up once again. This usually happens through the spring when the sun begins to gather strength across this large continent. The condition needed for a tornado is a warm feed of air, with lots of moisture, usually from the Gulf of Mexico. This meets cold air aloft, moving out of the arctic north behind strong moving cold fronts. The low level moisture is lifted ahead of the cold front which usually comes with a dry tongue of air in the upper atmosphere and the evaporation and condensation into the air then fires up large plumes of convection and thunderstorms that spawn the tornados, one of the most destructive weather types on earth.
Paul Stevens: weather blurb, March 9, 2011
Across in the States the tornado season has fired up once again.