South Carolina sees an average of 40 to 50 thunderstorm days per year while North Carolina sees an average of 50 to 60. Of those, about 10% are severe.
By definition, a severe thunderstorm contains any one or more of the following three weather conditions: A tornado, winds 58 mph or greater and/or hail that is 1 inch in diameter or greater.
Severe thunderstorms can occur in the Carolinas at any time during the year, but they are most likely from late March thru April.
Tornadic winds can range from 40 mph to nearly 300 mph. Thunderstorm straight-line winds can exceed 100 mph producing damage similar to a tornado. How do you determine which one produced the damage?
The best way to determine the difference is to fly over the area and look at the damage path.
Straight-line winds produce damage that typically lays in the same direction while torando winds often produce damage in a circular pattern.