In general, the degree of hotness or coldness measured against some definite scale by means of a thermometer. A local storm, usually produced by a cumulonimbus cloud, and always accompanied by thunder and lightning. The tornado usually appears from a bulge in the base of a cumulonimbus cloud. It has a typical width of tens to hundreds of metres and a lifespan of minutes to hours. In area, it is one of the least extensive of all storms, but in violence, it is the world's most severe.
More tornadoes occur in the United States than in any other country.
In Canada, when they do occur, it is mainly in the Prairies and southern Ontario. The opposite of a backing. A front that moves in such a way that the warmer air replaces the colder air. In meteorology, the intersection of warm and cold fronts. It includes temperature, pressure, humidity, clouds, wind, precipitation and fog.