 What had been the earliest storm to develop into a Category 5 hurricane in the Atlantic weakened to a Category 2 by the afternoon, but then strengthened back into Category 3 and headed for a likely direct hit on Mexico's Caribbean coast, where authorities urged tourists to leave white sand beaches. It regained strength late Thursday with wind speeds of 115 miles per hour as it neared landfall on Mexico's Yucatan Peninsula, according to the National Hurricane Center.