Monday, September 1, 2014

Tropical Storm Dolly (2014)

Storm Active: September 1-3

A tropical wave formed over the Central Atlantic around August 23 and began to produced disorganized shower activity as it moved westward. Atmospheric conditions remained hostile for development along the path of the system for nearly a week as it moved generally westward into the Caribbean. Even as upper-level winds improved on August 30, the tropical wave began to interact with the Yucatan Peninsula, inhibiting further development. Convection increased the next day even as the center of the developing low pressure center moved over land. By September 1, the broad low pressure system had moved west-northwestward into the Bay of Campeche, where a tighter circulation appeared. Though the center had primarily left the deep convection behind over the Yucatan, the system was organized enough by that afternoon to be classified Tropical Depression Five.

Initially, the only significant rain band associated with Five was well south and east of the center of circulation, in part due to moderate wind shear out of the north-northwest. However, convection flared up near the center of circulation overnight. Meanwhile, the center itself underwent several reformations, shifting the position of the system significantly to the north. By the morning of September 2, organization had increased significantly, and the system strengthened into Tropical Storm Dolly. That afternoon, Dolly's instability continued as the center reformed once again, this time significantly south of its former position. This movement made the cyclone more symmetric, and the central pressure decreased to 1002 mb, a minimum for Dolly. Near midnight, the system made landfall in Mexico.

The main threat associated with Dolly was flooding rains, which portions of Mexico received in abundance, for even as Dolly rapidly weakened into a tropical depression during the morning of September 3, new rain bands continued to appear over water and move inland. 5-10 inches of rain were expected for much of the affected area, with up to 15 inches locally. The assembly line of moisture continued through the next few day even though Dolly dissipated within 12 hours of landfall, fueled in part by the nearby Hurricane Norbert in the East Pacific.

The above image shows Tropical Storm Dolly on September 2.

The above image shows the track of Dolly.

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