TBO.com: Tampa Bay Online.
Friday, Oct 21, 2016

Scale for this year's hurricanes will be slightly different

MIAMI - A minor change is coming to the five-category system describing hurricane strength. The Saffir-Simpson Hurricane Wind Scale starts at Category 1 with top sustained winds at 74 mph. Categories 3 and above are considered "major." The National Weather Service says an adjustment was necessary to smooth converting units of wind speed measurement for public advisories. The change broadens the Category 4 wind speed range to 130-156 mph, instead of 131-155 mph. That shifts the Category 3 range to 111-129 mph, instead of 111-130 mph.
Category 5 hurricanes will have top winds of 157 mph or higher, instead of a threshold of 156 mph. Categories 1 and 2 remain unchanged. No historical storm records will be altered. The change takes effect May 15.