Sunday, June 19, 2016

Tropical Storm Danielle (2016)

Storm Active: June 19-21

A tropical wave moved over the eastern Atlantic from Africa during the first week of June. However, it being so early in the hurricane season, the system had no opportunity to develop further for nearly two weeks, when it began to produce thunderstorm activity near the coast of Nicaragua on June 15. The wave continued generally west-northwestward for the next few days, during which time land interaction inhibited organization. On June 18, it emerged into the Bay of Campeche, and a low pressure center formed in association with the wave. During the next day or so, moderate wind shear affected the system, hindering convective banding. However, the center of circulation became better defined on June 19 as shear gradually lessened, while increasing shower activity showed hints of banding in the northern semicircle. As a result, the system was designated Tropical Depression Four.

After a brief lull in convective activity that evening, a large area of deep convection blossomed overnight, albeit not all that organized about the center of circulation. By the morning of June 20, reconnaissance aircraft discovered gale force winds in the system, prompting an upgrade to Tropical Storm Danielle. This was the earliest naming of a fourth storm in the history of Atlantic hurricane seasons, beating out the record set by Tropical Storm Debby in 2012 by 3 days. Heavy rain began over the Mexican coast on the west side of the Bay of Campeche and continued as Danielle moved west-northwestward toward land. Danielle reached its peak intensity of 45 mph winds and a minimum pressure of 1007 mb before making landfall in Mexico that evening. The storm brought 8-12 inches of rain to a large area of Mexico as it quickly weakened over the mountainous terrain of Mexico. It dissipated early on June 21.

During its brief period as a tropical system, Danielle brought heavy rains to eastern Mexico.

Forming in the central Bay of Campeche, Danielle did not have time to strengthen significantly before it moved westward over land.

Sunday, June 5, 2016

Tropical Storm Colin (2016)

Storm Active: June 5-7

Around June 3, a large area of disturbed weather formed over the northwestern Caribbean Sea. The next morning, a broad low-pressure center developed in association with the system just east of the Yucatan Peninsula. Moving over land that day, it was unable to organize further and convection remained over water well to the east. On June 5, however, the center emerged into the Gulf of Mexico. Shortly after, the low had acquired enough organization to be classified Tropical Depression Three. Due to shear out of the west, the depression's thunderstorm activity, though significant, was located in a north-to-south linear band over 100 miles east of the circulation center. Despite this disorganization, hurricane hunter aircraft discovered winds to tropical storm force that afternoon, prompting an upgrade to Tropical Storm Colin. The formation of the year's third named storm on June 5 broke the record for earliest third tropical storm, set on June 12, 1887.

Colin exhibited a very curious structure for a tropical cyclone. Overnight and into June 6, it was apparent that there were at least two distinct low-level centers widely separated from one another, both of which lay outside the intense area of convection to the east. The size of the system and its disheveled state were prohibitive to significant strengthening. Despite this, the impacts of the storm remained: by June 6, with Colin still over water, heavy rains spread throughout much of Florida, Georgia, and even South Carolina. The system consolidated a bit that day into a single circulation, albeit with several small-scale gyres. Meanwhile, it was accelerating rapidly toward the northeast. That evening, the center of Colin made landfall in the Big Bend region of Florida (although most of the rainfall had moved off to the east by this time).

Though at its peak intensity as a tropical system of 50 mph, the system was more disorganized than ever as it sped off to the northeast, quickly emerging off the coast of the Carolinas early on June 7. At this point, Colin was rapidly losing tropical characteristics, and it become post-tropical near the Outer Banks later that morning. By the afternoon, the system had moved away from land, still intensifying as a post-tropical system. It continued to speed toward the far northern Atlantic before being absorbed a few days later.

Colin remained disorganized during its brief stint as a tropical system. The above satellite image, taken June 6, shows multiple vortices exposed to the west of the convective canopy.

Colin made landfall in Florida on June 6 before quickly moving out to sea.