When the calendar turned from May to June, a collective sigh of relief likely occurred for residents of Tornado Alley, Dixie Alley and any other alley often a target for May tornadoes. More tornadoes occur on average in the United States in May (269) than any other month, but May 2020 was unusually quiet.
There were just 139 preliminary reports of tornadoes in May nationally - a massive 60 percent decline from April's total of 351, according to the National Oceanic and Atmospheric Administration's (NOAA) Storm Prediction Center (SPC).
The last time there were more tornadoes nationally in April than May was 2014, though April has outpaced May in tornado activity six times over the last 16 years (2005, 2006, 2009, 2011 and 2012).
May 2020 had the fewest number of tornado watches issued by SPC in recorded history (1970-present) and the month had the fewest number of EF2+ tornadoes in recorded history (1950-present).
The May decline followed an April that was off the charts, with 351 tornadoes in the U.S. - the second-most of any April, according to SPC records, topped only by April 2011 (1,085). And last May, a total of 506 tornadoes occurred - roughly 46 percent more than May's average and just off the record of 542.
"The huge dip in severe weather in May has brought the pace for 2020 below normal based on the 2005-2015 average for number of tornadoes to date," said AccuWeather Lead Long-Range Meteorologist Paul Pastelok. "We anticipate that an active tropical season and warm early fall can lead to increased tornadoes from August through October."
For June, AccuWeather is predicting 125 to 175 tornadoes in the U.S., which is below the average monthly total of 229. AccuWeather predicts a normal to slightly above-normal number of tornadoes nationwide for all of 2020, with a range of 1,325 to 1,400. That range almost would cover what occurred in 2019 (1,422) and is roughly 5 to 8 percent more than the annual average for the U.S. (between 1,253 and 1,297 tornadoes occur annually in the U.S.).
A total of 733 tornadoes have occurred through the end of May in 2020, according to the SPC's preliminary reports. The three-year average is 749, meaning there have been just two percent fewer tornadoes this year.
Moving forward, "Tropical impacts in June and August could spawn more tornadoes along the Gulf coast," Pastelok said.
Although tornadoes can occur at any time, the U.S. tornado season typically runs from March through November or sometimes into early December. Tornadoes cause an average of 80 U.S. fatalities annually, and tornadoes and their destruction killed a total of 41 people in 2019. A total of 74 tornado-related fatalities have occurred so far in 2020.
The current average number of U.S. tornadoes per year based on long-term data is lower than what actually occurs each year. The reason for this is due to the number of tornadoes reported annually which has been rising over the past few decades. This is mainly because more are reported as the U.S. population has risen and more people have access to mobile devices and cameras. Many tornadoes of the past were not seen or recorded; this change may amount to an increase of reported tornadoes of up to 20 percent over the last 40 years and 10 percent over the past 20 years.