Saturday, October 30, 2010

Hurricane Tomas (2010)

Storm Active: October 29-November 7
On October 25, a tropical wave formed in the extreme southeastern Atlantic Ocean, near 5ºN. The wave produced only scattered shower and thunderstorm activity as it moved west over the next few days. It was a vigorous tropical wave, however, and it developed a low pressure center on October 27. The low adopted a general northwest motion, and deepened significantly over the next two days. By the afternoon of October 29, the system had a very organized circulation and outflow, and the confirmation of a closed low at its center merited the upgrading of the system into Tropical Storm Tomas.

Tropical Storm Tomas was already in a state of rapid intensification, and the winds increased rapidly as the cyclone approached the Caribbean Islands, moving westnorthwest between 10 and 15 mph. During the morning of October 30, Tomas passed directly over Barbados, with peak winds of 70 mph, causing fairly significant damage. Tomas developed a very wide eye feature (about 40 miles across) just before noon on October 30, and it was then organized enough to be upgraded to a Category 1 hurricane.

The system promptly made a direct landfall in St. Vincent during that afternoon, and heavy rain and tropical storm winds affected islands up to 100 miles north and south along the Windward and Leeward Islands. The wide eye clouded over with a flare of convection, and Tomas continued to strengthen, becoming a Category 2 by later that night. However, southwesterly shear and dry air began to impact the west side of the system early on October 31, weakening it to a Category 1 storm by the afternoon. The center became ragged in appearance, and lost definition as a result of harsh atmospheric conditions.

Tomas weakened further into a tropical storm during the night, and only stabilized on November 1, when the winds dropped to 45 mph. Tomas was pushed on a general westsouthwest course during the day. Tomas's intensity fluctuated with large variations in convection over the day of November 2. The cyclone's forward speed also decreased as it reached the edge of a ridge to its north and steering currents weakened. For a brief period on November 3, Tomas degenerated into a wide area of scattered convection covering the entire southwest Caribbean, and was therefore downgraded to a depression, but the conditions for development drastically improved later in the day and Tomas turned towards the north, and the storm underwent a fast strengthening process, regaining tropical storm status. Tomas reached an intensity of 50 mph winds, and maintained it for the next day as it slowly moved northward. Wide rain bands began to sweep across Jamaica, Haiti and Cuba by the afternoon of November 4. As Tomas approached land, it rapidly strengthened into a hurricane, reaching its secondary peak intensity of 85 mph winds and a pressure of 984 mb as it passed just west of Haiti on November 5.

Cuba and Haiti both experienced tropical storm conditions, as well as hurricane force in some areas of Haiti, as the day went on, and as Tomas began to accelerate northeast, it interacted with the land around it briefly, and weakened back to a minimal Category 1 hurricane later in the evening. Tomas passed over the Turks and Caicos islands overnight, but emerged over open Atlantic waters on November 6, weakening back to tropical storm. Unexpectedly, Tomas once again regained hurricane strength late on November 6, but a cold front quickly overtook the system, and Tomas rapidly transitioned into an extratropical low on November 7. 41 fatalities and $572 million in damage directly resulted from Tomas in the Caribbean Islands, but Tomas is also indirectly linked to an epidemic of cholera in Haiti.

Hurricane Tomas intensifying as it enters the Caribbean. A fair amount of wind shear is evident on the south side of the system.

Track of Tomas.

1 comment:

Avinash Kissoon said...

that is very destructive.