(Radio Iowa) – State Climatologist Justin Glisan says Iowa has been in a severe weather drought for the past three years. So far this year, there have been three dozen confirmed tornadoes in the state.

Over the past four decades, Iowa has been averaging 48 tornadoes a year. June has generally been the peak month for tornado activity in Iowa, but it appears there’s been just one tornado reported in the state this month. There were multiple tornadoes on March 31st, though. The National Weather Service office in the Quad Cities confirmed at least 30 tornadoes in eastern Iowa and western Illinois on that date.

Keota-tornado-Josh-Franzen-photo-via-NWS-

Warm, humid air near the ground and cold, dry air above are the ingredients that spawn a tornado out of a thunderstorm.

But Glisan says the latest research indicates relative humidity will be trending upward in the years ahead. Glisan made his comments during a recent appearance on Iowa Press on Iowa P-B-S.