Hurricane Irene (1999) - Meteorological History

Meteorological History

A broad area of low pressure formed over the western Caribbean Sea on October 8, and it persisted until October 11, when a tropical wave reached the area and caused the convection to organize, resulting in the development of a low-level circulation. Convection increased and organized around the circulation's center late on October 12, and the system organized into Tropical Depression Thirteen on October 13 off the north coast of Honduras. The depression continued to organize over the favorable conditions present in the Caribbean Sea, and attained tropical storm status later on October 13, when it was assigned the name Irene. Operationally, the system remained a tropical wave until it already reached tropical storm strength.

Tropical Storm Irene strengthened as it moved northward, and reached maximum sustained winds of 70 mph (115 km/h) early on October 14. Operationally, Irene was upgraded to a hurricane on October 14, although later analysis after the hurricane season indicated it remained a tropical storm until later. Irene continued to move towards the north-northeast, crossed over the western portion of the Isla de la Juventud as a strong tropical storm, and hours later, it struck mainland Cuba near Batabano. The storm was able to strengthen further over the Florida Straits, and Irene attained hurricane status on October 15. It passed over Key West, turned more to the north-northeast, and struck mainland Florida at Cape Sable as an 80 mph (130 km/h) hurricane.

Irene entered the Atlantic Ocean near Jupiter, Florida early on October 16, still as a Category 1 hurricane. It turned to the north, remained a hurricane despite little convection, then turned to the northeast in response to an approaching upper-level trough. Just offshore, Irene moved parallel to the coastlines of South Carolina and North Carolina on October 17. On October 18, as it interacted with very warm ocean waters and the upper level trough, Irene rapidly intensified, reaching peak winds of 110 mph (175 km/h) with a pressure of 952 mbar, a Category 2 hurricane. Despite its strength, the circulation was very asymmetrical, and the convection was not particularly organized. The hurricane continued to accelerate to the northeast, steadily weakening until becoming extratropical on October 19 to the south of Newfoundland. The extratropical storm continued to the northeast until becoming absorbed by another, larger extratropical storm late that same day.