June is typically the peak month for tornadoes across our region. What is it about June weather that causes tornadoes to form? The classic answer, “Cold air from the north clashes with warm and humid air from the Gulf of Mexico,” is a silly oversimplification.
In reality, tornadoes form as a secondary circulation developing from crosswind interaction underneath a powerful, rotating updraft region of a thunderstorm. Although some weak tornadoes can form from rather mundane thundershowers, the truly life-threatening tornadoes are almost always associated with a well-developed severe storm. These supercell thunderstorms are also capable of producing large hail and damaging winds and often generate straight-line wind damage in other parts of the storm.
Supercell storms are usually found in an environment of strong upper level wind blowing stronger than, and at an angle to, surface winds and also where surface air is especially buoyant (unstable). Warm and humid air underneath a pool of cold air aloft is ideal for instability.