MEMPHIS, Tenn. (WMC) - May is known to be the most active month for tornadoes in the U.S. On average, May produces 272 tornadoes each year starting back from 1999 through 2018. The lowest number of 34 tornadoes in May of 1952 was the lowest amount ever, since records have been kept.
In 1970 only 88 twisters recorded and this May of 2020 only produced 59 which is one of the lowest in a long time.
However, April was one of the more active months and it included the deadly Easter tornado outbreak in Middle Tennessee. There were 351 tornadoes just in April. May usually produces close to two times more tornadoes than the month of April.
May tends to be more active than April because the ingredients come together a lot better for tornado formation.
Some of the ingredients needed, that come together in May are moisture being pulled north usually due to a low pressure system, afternoon heat and humidity and a strong jet stream that is centrally positioned across the US. and not too far north. The jet stream gives of the wind shear which is the turning of wind with height.
Some of the things we didn’t see was a strong jet stream and temperatures for may came in below average for many areas across the eastern half of the US.
The upper level pattern, ultimately wasn’t favorable this May.