[1] A significant number of tornadoes in both months came from the tropics.
August had 180 tornadoes, which was well above average, with 55 of them coming as a result of Hurricanes Isaias and Laura.
In contrast, September saw only 38 tornadoes, which was well below average, with 23 of them coming from Hurricane Sally and Tropical Storm Beta.
Tornadoes were associated with Hurricane Isaias excluding the events in the Dakotas and Colorado.
Event in South Carolina was indirectly associated with Tropical Storm Beta.