Who knew that tornadoes could be like Baby Bear. It can’t be too hot. It can’t be too cold. It has to be j-u-u-u-s-s-s-t right!
Spring tornadoes are like car crashes. When hot, moist air and cold air collide, it gets messy.
The greater the contrast between the air mass temperatures, the more energetic the storm.
That’s why most early tornadoes usually start in along the Gulf, where the warm wet air from the Gulf of Mexico hits the cold winter air.
As spring continues and the warm air moves north, so do the majority of tornado producing storms, particularly in the “Tornado Alley” of the Great Plains.
You usually need that balance of hot and cold air to brew a tornado.
Tornado Alley – where conditions are j-u-u-u-s-s-s-t right! Source: NOAA
Last year, for example, was too hot. It started out with the busiest January tornado season on record and March saw a record amount of tornadoes as well.
However by late April the cool air was pinned far north in Canada and May was quiet. By the end of year, 2012 set a record of being the quietest US tornado season in history. It only (ONLY!) had 882 tornadoes, and didn’t have a single strong EF 5 event. The heat and the drought were miserable, but at least people were safe from violent storms.
Until recently, this year has been too cold. After a busy January, the storm season flat-lined. March, which normally averages 98 tornadoes, had only 17 twisters.
The tornado season of 2013 was busy, then it flat-lined. Source: NOAA
However, weather experts are warning that the quiet is coming to an end. Mid-April through May is the peak of the tornado season. They warn that the South will be getting welcome rain and unwelcome tornadoes this month.
It’s been too hot, then too cold. Now it’s just right for even the most finicky tornado. So be careful out there!
Evelyn Browning Garriss, historical climatologist, is a longtime writer for The Old Farmer's Almanac. She is also editor of The Browning World Climate Bulletin  and has advised farmers, businesses, and investors worldwide on upcoming climate events and their economic and social impact for the past 21 years.