Monday, September 12, 2016

Tropical Storm Ian (2016)

Storm Active: September 12-16

Near the end of September's first week, a tropical wave developed over the central Atlantic. Soon, a low pressure center developed along the southern portion of the wave and began to produce a large area of showers and thunderstorms. Despite conditions being very favorable for development, the system organized only slowly as it moved northwestward. By late on September 11, the low was producing gale-force winds. However, it did not yet possess a well-defined center of circulation. Despite the fact that upper-level winds had increased somewhat, the low managed to organize into Tropical Storm Ian during the morning of September 12.

Convection remained confined to the northeast of the center through the remainder of that day. Meanwhile, the system turned toward the north-northwest well to the east of the Lesser Antilles. The area of tropical storm force winds did experience an expansion that evening, and maximum winds increased somewhat, but Ian's structure did not meaningfully change until the afternoon of the 13th. At that time, convection managed to cover the center for the first time. However, the cyclone began to lose tropical characteristics shortly afterward, with the circulation becoming broader and losing concentrated thunderstorm activity near the center. By the morning of September 15, it was accelerating north-northeast over the open Atlantic. Ian actually appeared more tropical later that day than it had for a couple days, with deep convection reappearing close to the circulation center. However, it was racing toward the north Atlantic by this time, briefly achieving a forward speed of over 50 mph that night. At the same time, it experienced some intensification, reaching 60 mph winds and a pressure of 994 mb by the morning of September 16. The cyclone in fact continued strengthening as it became extratropical that afternoon. It merged with another strong low over the north Atlantic shortly afterward.

The image above shows Tropical Storm Ian shortly after formation.

Ian did not affect any landmasses over its short lifetime as a tropical cyclone.

No comments: