Tropical Storm Erin (2013)

Storm Active: August 14-18

A strong tropical wave and associated low pressure system moved off of the African coast on August 13 and immediately began to organize. The next day, convection concentrated near the center as the system began to pass south of the Cape Verde Islands, bringing showers and some windy conditions. By the evening of August 14, the disturbance was sufficiently organized to be classified as Tropical Depression Five. At first, the highest winds were not situated over the center of circulation, but organization continued as the system tracked west-northwest, and by the morning of August 15, Five had strengthened into Tropical Storm Erin.

During that day, Erin was already struggling with the atmospheric dry air still present in that region of the Atlantic, fluctuating between periods of strong convection and nearly none at all. Meanwhile the cyclone turned slightly toward the northwest into a weakness in a ridge to its north, and entered a region of somewhat cooler waters. On August 16, wind shear out of the southwest increased also, driving convection off to the east of Erin's center, and the system was downgraded to a tropical depression. Late that night, however, a burst of convection reappeared, and satellite data suggested that Erin had restrengthened into a tropical storm.

Erin's new status was not to last, though, as the hostile conditions again tore away the cloud cover over the system's center of circulation on August 17. By that evening, the center also showed signs of elongation, and Erin was again downgraded to a tropical depression. The cyclone continued to degenerate on August 18, and became a remnant low that afternoon. The remnant low dissipated over the open Atlantic by August 20.

The image above shows Erin shortly after being named. The cyclone achieved only minimal tropical storm status.

A weakness in the subtropical ridge to its north allowed Erin to move northwestward into cooler water and very hostile atmospheric conditions. These conditions promptly dissipated the system.