The 13th tropical depression formed just east of the Lesser Antilles on September 8. As it moved west-northwest, it became Tropical Storm Gilbert over the islands on September 9. The tropical storm turned west and rapidly intensified to a major hurricane on September 11. Gilbert continued to strengthen as it brushed the southern coast of Hispaniola. It passed directly over Jamaica as a Category 3 hurricane and brought torrential rains to the island's mountainous areas. When the center reemerged over water, Gilbert rapidly intensified again. On September 13 the central pressure dropped , the fastest deepening of an Atlantic hurricane on record until 2005's Hurricane Wilma. Gilbert's pressure of at the time was the lowest sea level pressure ever recorded in the Western Hemisphere.