Friday, June 25, 2010

Hurricane Alex (2010)

Storm Active: June 25-July 1
On June 12, a strong tropical wave moved off of Africa and persisted westward. For the next week, it was held within the Intertropical Convergence Zone, and showed no signs of development. On June 20, the tropical wave moved into the Caribbean, and moved slightly northward on its westerly track. The wave tapped into the large amount of moisture in the Caribbean and developed a broad area of convection with little organization. The wave continued through the Caribbean, encountering increasingly favorable conditions as it went, and slowly organized. On June 24, a low became associated with the tropical wave, but most convection was still to the east of the circulation. However, the convection soon concentrated at the center of the system, and soon developed an apparent circulation. On June 25, an aircraft reconnaissance mission confirmed the existence of a closed circulation and the system was declared Tropical Depression One off the coast of Honduras.

Tropical Depression One continued to gain organization, and was declared Tropical Storm Alex the following morning as it moved westnorthwest at 10 mph towards the Yucatan Peninsula. During the day of June 26, Alex assumed a more westerly track, and gained intensity as its thunderstorm activity concentrated toward the center. As a result, Alex reached an intensity of 65 mph winds and a central pressure of 996 mb, before making landfall in central Belize at approximately 9:00 pm EST June 26. Alex remained over land for the next day, weakening as it went, and by the morning of June 27, Alex was downgraded to a tropical depression. Alex maintained its impressive circulation, but cloud cover depleted, as the system did not receive new water to fuel itself as it moved westnorthwestward at 12 mph. Alex slowed down and turned more to the northwest as it emerged into the Gulf during the evening of June 27, allowing for more time over the favorable Gulf, and more strengthening. As Alex reemerged over water, deep convection immediately started to appear around the center, and the system was once again upgraded to a tropical storm overnight, as it moved slowly northwest. Mild shear affected the system, but it strengthened nevertheless during the day of June 28. However, the shear lessened on June 29, and the system strengthened to a hurricane overnight.

Alex began to turned westward again, as its outer bands swept across the coast of northern Mexico and southern Texas. Alex continued west, and strengthened further, reaching its peak intensity of a category 2 hurricane with 105 mph winds and a minimum pressure of 947 mb just before landfall in northern Mexico at 10:00 pm EST June 30. Alex then began weakening, becoming a category 1 hurricane by very early the next morning, and a tropical storm a few hours later. All warnings and watches were quickly discontinued as the convection associated with Alex continued to weaken. By the late evening of July 1, Alex's circulation and vorticity were gone, and the system had dissipated. However, Alex caused $1.21 billion in damages, and 32 deaths were associated with the system. As a result, Alex was already much more costly and much more deadly than the entire 2009 Atlantic hurricane season! Also, Alex was a fairly rare event climatologically, being the first June hurricane since 1995, and the most powerful in central pressure since 1957.

Image of Alex near peak intensity just before landfall in Mexico.

Track of Alex.