Sunday, August 30, 2009

Tropical Storm Danny (2009)

Storm Active: August 26-29

On August 20, a tropical wave moved off Africa. It showed little signs of organization, but it was monitored for development. The cloud cover diminished on August 22, but flared up again on August 23, as the wave interacted with an upper-level low to its northwest. The low, sheered the system, but it also fueled increasing convection around the wave over the next two days. As the tropical wave passed under the low on August 25, sheer lessened, and more organization was evident. The wave ad strong enough winds to be considered a tropical storm, but still lacked a specific center of circulation. However, this appeared on the morning of August 26, and the wave-low interaction was upgraded directly to Tropical Storm Danny. Danny had most cloud activity to the northeast of the center, and wasn't that organized. Despite this, stronger winds were found in the system and Danny strengthened, reaching its peak intensity of 60 mph winds and a pressure of 1006 millibars that night. Danny was heading generally northwest, but meandered north of the Bahamas, sometimes going west, north, even south. As Danny slowly made its way towards the U.S. east coast on August 27, it encountered less favorable conditions and began to weaken as its convection became increasingly displaced to the east of its center. By August 28, Danny was a minimal tropical storm, and was steered more northerly by a ridge of high pressure of the southeastern United States. Early on August 29, Danny was downgraded to a tropical depression off the Outer Banks of North Carolina. The last advisory was issued at 5 a.m. Eastern Standard Time that morning as Danny merged with a frontal low pressure system in the Northeast. Danny helped to enhance the moisture in the region even more, causing 2-4 inches of rain over various areas of New England. The merged low and accompanying frontal boundary continued northeast, eventually causing heavy rain in the Canadian Maritime on August 30. Danny, having never made landfall as a tropical system, caused little damage, and one fatality resulted from rip currents on the coast of North Carolina.

Visible satellite image of Danny while maintaining its peak. The center is highly evident as a swirl of clouds well outside the cloud cover, which is all east of the center.

Track of Danny.

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