Based on tornado records going back to 1950, this significantly tops the previous September record of 139 tornadoes set in 1967. Other high numbers for September include: 104 in 1998; 101 in 1996; and 84 in 2001. The average number of tornadoes in the U.S. during September is 47.
“The extremely active tropical storm season can be partially blamed for the high number of tornado reports,” McCarthy said. Three land-falling hurricanes—Frances, Ivan and Jeanne—affected the mid-Atlantic and Southeast states during September. Tornadoes frequently occur in the northeast quadrant of northward advancing tropical systems or their remnants. “This is the sector where wind shear has its greatest affects on storms in the rain band,” McCarthy explained.
With 117 reports, Hurricane Frances produced the most tornadoes ever, topping Hurricane Beulah's 115 tornadoes in September 1967. Hurricane Ivan was close with 104 tornado reports, and a total of 16 tornadoes were reported in association with Hurricane Jeanne.
September's record follows a record-breaking 173 reports during August, partially due to Tropical Storm Bonnie, with 30 tornado reports, and Hurricane Charley, with 25 reported tornadoes.
"With a total of 292 tornado reports associated with land-falling tropical systems, this has been the most active period since 1967," McCarthy said. "Never has there been four tropical systems produce so many tornado reports affecting Florida northward into Maryland."
September also proved to be a deadlier month, with eight tornado-related fatalities. This compares to only three tornado related fatalities in August.
The total number of tornadoes reported in 2004 so far is 1,516, already surpassing 1998's record total of 1,424 tornadoes for the year. The actual number of tornadoes for 2004 will not be known until June 2005.
