(Radio Iowa) State Climatologist Justin Glisan says a tornado outbreak is unlikely this month because Iowa is in a severe weather drought.
“When you don’t have thunderstorms to drive rainfall, you don’t get a lot of severe weather and you get into pervasive drought,” Glisan says. So far this year in Iowa there have been 63 confirmed tornadoes.
“Four percent of the tornadoes that we see across the state of Iowa occur in September, so not a particularly high number,” Glisan says, “but recently back in 2018 we had 12 September tornadoes and then in 2019 we had nine and that’s an interesting thing to look at because 2018 was the second wettest year on record, 2019 the 10th wettest on record, so we had a very active storm track through fall.” The mid-Atlantic and southern states are getting a lot of rain right now during hurricane season, but Glisan says those storm systems rarely bring beneficial rainfall to Iowa.
“We did have a June tropical system back in 2019 that made it into eastern Iowa,” Glisan says, “and that had been the first time since 1900 that we had seen a tropical system actually make it into Iowa.” Glisan says what he calls the “moisture gate” from the Gulf of Mexico is blocked off right now, preventing the development of thunderstorms. Glisan warns, though, that tornadoes occurred in every month of the year.
“Think back to the December 15th outbreak in 2021 — 63 tornadoes across the state, the highest tornado count for any month in the state of Iowa,” Glisan says, “but also the highest tornado outbreak for a December outbreak in United States history.”