violent storm

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A wind with a speed ranging from 56 to 63 knots (64 to 72 miles per hour; 104 to 117 kilometers per hour), according to the Beaufort scale.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a violent weather condition with winds 64-72 knots (11 on the Beaufort scale) and precipitation and thunder and lightning