Violent tornado rakes Tennessee

Tornadoes and severe thunderstorms ripped through Missouri, Arkansas, Illinois, Ohio, Tennessee, and surrounding states Sunday, killing at least 23 people. Hardest hit was northwest Tennessee, where tornadoes claimed at least 12 lives in Dyer County. Damage reports indicated that many houses in the tornado's path were completely destroyed leaving only the foundation, making it likely that the Dyer County tornado will be ranked as a violent F4 tornado (207-260 mph winds) on the Fujita scale. This would be the second F4 tornado of the year--an F4 tornado struck Monroe City, MO on March 13, as part of an 84-tornado assault on the Midwest that also featured 11 strong F3 tornadoes. There is a slight possibility that last night's Dyer County tornado was an F5--the most violent type of tornado, capable of incredible damage--but we won't know until the National Weather Service has a chance to get out today in daylight and perform a damage survey. The U.S. has not had an F5 tornado since the infamous Moore, Oklahoma tornado of 1999, which had the highest winds ever recorded in a tornado, 301 mph. The U.S. has already equalled last year total of F4 tornadoes (one), and this Spring's severe weather season is shaping up to be far more deadly and destructive than last year's unusually quiet one.


Figure 1. Damage reports for the 24 hours ending at 9am EST April 3 show the wide scope of yesterday's severe weather.

The threat for severe weather continues today. The "Moderate Risk" area in the latest outlook by the Storm Predisction Center covers a region unused to seeing tornadoes--coastal areas of North Carolina, Virginia, and Maryland. A strong cold front will push across the region this afternoon, creating a squall line with embedded supercells likely to produce tornadoes, damaging straight-line thunderstorm winds, and hail golf ball size and larger. The severe weather episode will end tonight as the cold front pushes off the coast and more tranquil weather returns to the U.S.

Tomorrow: An update on the severe weather outbreak, plus a look at Dr. Bill Gray's new forecast for the hurricane season of 2006.

Jeff Masters