Sunday, May 20, 2012

Tropical Storm Alberto (2012)

Storm Active: May 19-22

On May 17, a cold front moved off of the U.S. East Coast. The southern end of the front stalled off of the coast of South Carolina, and a low pressure trough developed. Over the following two days, the area of low pressure remained nearly stationary, and began to acquire tropical characteristics, which, during the afternoon of May 19, were enough to classify it as Tropical Storm Alberto, the first tropical cyclone of the 2012 Atlantic Hurricane Season.

The system drifted slowly to the southwest and west-southwest over the following day, and the devtelopment of modest convection near the center late on May 19 allowed the system to reach its peak intensity of 60 mph winds and a minimum central pressure of 995 mb. Early on May 20, the shear from a low pressure system to its northwest intensified, and the circulation became exposed mid-morning, weakening Alberto. As the day went on the blocking pattern that was in place over the U.S. northeast and the northwest Atlantic Ocean receded, and Alberto quickly shifted its motion from southwest to south to east and then northeast.

Accelerating as it did so, the system weakened further to a minimal tropical storm and then a tropical depression on May 21. By May 22, the convection was strongly displaced from the circulation center, and Alberto became extratropical later that morning, while southeast of Cape Hattaras, North Carolina. The next day, it merged with a front coming off of the U.S. Alberto was the earliest forming cyclone in the Atlantic basin since Ana in 2003, and 2012 was the first year on record such that a preseason cyclone formed in both the Atlantic and East Pacific Basins.

Alberto near peak intensity on May 19.

Track of Alberto.

1 comment:

Anonymous said...

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