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.

Tropical Storm Claudette (2009)

Storm Active: August 16-17

On August 11, a scattered area of showers and thunderstorms became associated with a tropical wave over the Bahamas. The wave showed little to no organization over the next few days as it moved westward, and tracked south of Florida. On August 15, upon entering the Gulf of Mexico, the wave became significantly better organized, and on August 16, was classified Tropical Depression Four, with 35 mph winds and a central pressure of 1011 millibars. Later that same day, Tropical Depression Four became Tropical Storm Claudette. The system quickly reached its peak intensity of 50 mph winds that evening. Overnight, technically very early on August 17, Eastern Standard Time, Claudette made landfall in the panhandle of Florida. The system's central pressure briefly decreased after landfall, but then Claudette became a remnant low late on August 17. For a few more hours, the remnants of Claudette continued northwest, before it dissipated on August 18. Two fatalities occurred as a result of this system, and damages totaled around $1.2 million.

Claudette near peak intensity in the Gulf of Mexico.

Track of Claudette.

Tuesday, August 18, 2009

Hurrricane Bill (2009)

Storm Active; August 15-24

On August 11, a strong tropical wave moved off Africa. It took a few days to organize, but on August 15, it became Tropical Depression Three, with 35 mph winds and a pressure of 1006 millibars. A few hours later, Three became Tropical Storm Bill. Unlike the previous storm Ana, Bill quickly stregthened and became the first hurricane of the 2009 season on August 17 with 75 mph winds and a pressure of 987 millibars. It took a west-north-west track, which allowed for more favorable conditions. Inside the well-organized circulation, eyewall and eye structures quickly formed. A large area of high pressure kept Bill on this track, as it continued to gain strength. By August 18, it was a Category 2, with 100 mph winds and a pressure of 967 millibars. Then, overnight, Bill rapidly intensified into a Category 4 hurricane, with winds of 135 mph and a pressure of 948 millibars. Later that same day, Bill made its closest approach to the northeasternmost islands of the Caribbean, causing high surf but no other effects. On August 20, the ridge of high pressure keeping Bill to the south weakened, allowing Bill to take a northward turn. Bill slowly weakened, and on August 21, began to batter Bermuda with tropical storm force winds as a Category 2. Bill continued north, accelerating over time, and brushed Cape Cod with its outer bands causing huge surf and rip currents. On August 23, Bill's center paralleled the coast of Nova Scotia, staying barely offshore. At this time, Bill was turning east and was a minimal Category 1 hurricane. Late that night Bill made a landfall in Newfoundland and had passed by a mere six hours later. Early on August 24, Bill was a tropical storm, and, going east at 43 mph, Bill finally became extratropical. It continued eastward, and its extratropical remnants eventually brought wind and rain to Great Britain and surrounding areas. Bill caused two fatalities, both as a result of high surf on the east coast of the U.S.

Sorry, but an image of Hurricane Bill is not currently available on this website. To see one, click here.

Track of Bill.

Tuesday, August 11, 2009

Tropical Storm Ana (2009)

Storm Active: August 11-17

On August 8, a strong tropical wave emerged off Africa. It showed a lot of organization, and therefore was classified a tropical depression on August 11. Tropical Depression Two had 30 mph winds and an internal pressure of 1006 millibars on its first advisory, but it showed signs of strengthening. It also had minor effects on the southern Cape Verde Islands. Tropical Depression Two became more organized on August 12, when convection became more defined and covered the center of circulation. However, the system was still a tropical depression with 35 mph winds and a pressure of 1006 millibars. That night, however, the depression lost its cloud cover due to wind sheer, and weakened back to 30 mph winds on August 13. Despite some regeneration of the convection later that day, it was downgraded to a remnant low. However, cloud cover came back to the system slowly and on August 15, it became Tropical Depression Two once again. Then, six hours later, it became the first named storm of the 2009 season with its peak intensity of 40 mph winds and a pressure 1005 millibars. The newly named Tropical Storm Ana continued westward and interacted with the easternmost islands of the Caribbean, causing little damage. Only rain and some tropical storm force winds resulted. As it plowed deeply into wind sheer, the system weakened and became Tropical Depression Ana south of Puerto Rico. It brought periods of showers and winds to the island, before becoming a remnant low on August 17. The low continued west-north-west over the next few days, and dissipated near Florida on August 19. Damage from Ana was minimal and no fatalities resulted from this system.

Tropical Depression Two before dissipating and regenerating into Tropical Storm Ana.

Track of Ana.