68 NC counties and 1 VA county are under alert, including Wake, Cumberland, Durham, Johnston, and Orange counties. Details
Published: 2008-05-07 12:12:09
Updated: 2008-05-07 12:12:09
Posted May 7, 2008
By Jim Ferry
MIKE MOSS SAYS: The probability of strong and violent tornadoes (EF2 and above) is very low in both places, but they certainly aren't unknown, recalling that an F4 storm struck Raleigh in 1988 (see http://www4.ncsu.edu/~nwsfo/storage/cases/19881128/ for details). Statistically, the probability of a strong or violent tornado on a given day in the spring for the Triangle area is about .07 percent, versus about .04 percent for the Suffolk area. Looked at a different way, the probability for the month of April that a tornado of EF2 or higher intensity will occur within 25 miles of a point for our area is roughly 1.5 percent, while for the Suffolk area it is around .9 percent.
These numbers are very small due to the infrequent nature of strong and violent tornadoes and also due to the relatively small amount of land area affected by storms that are typically a few hundres of years across and a few miles long, but that in no way diminishes their seriousness or the impacts felt when they do occur.
The satistics above are drawn from a set of maps and graphs compiled by a researcher at the National Severe Storms Laboratory. There is a lot more to explore at his Severe Storms Climate site. If you're interested in exploring this more, the address is