User:Jdorje/2005 Atlantic hurricane season/Hurricane Irene (2005)



Tropical Depression Nine formed from a tropical wave west of Cape Verde on the afternoon of August 4, the second Cape Verde-type storm of the season. The system was expected to strengthen rapidly, but the depression encountered dry air and wind shear as it turned to the northwest and it broke down. Despite poor organization and shearing winds, it reached Tropical Storm strength for a while on August 7–8 and received the name Irene. Further shear and dry air disrupted the cyclone formation, and Irene was downgraded to a tropical depression on August 8.

Irene cycled between apparent reintensification and significant weakening, becoming so disorganized in the early morning of August 10 that forecasters were considering declaring that it had dissipated. However, the depression continued to move westward into warmer waters and shear-free environment, and again attained tropical storm status, rapidly strengthening to just under hurricane strength before leveling off again. On August 14 at 2144 UTC, an Air Force Reserve hurricane hunter read winds of 75 mph (120 km/h), making Irene a minimal Category 1 hurricane. Later, it strengthened even further in low shear conditions under an upper level anticyclone. On August 16 its winds briefly strengthened to that of a Category 2 hurricane, but shortly thereafter Irene began to reach cooler waters and weaken. It became extratropical 290 statute miles (470 km) off Cape Race, Newfoundland, on August 18, having never posed a threat to land.


 * The NHC's archive on Hurricane Irene.