Hurricane Isaac was the tenth named storm, as well as the fifth hurricane of the 2006 Atlantic hurricane season, and the final storm to form in the season. Isaac formed in late September from a tropical wave that exited the coast of Africa. Even though Isaac lasted into October 2, no tropical storms formed in October; the first time this has happened since the 1994 Atlantic hurricane season. Isaac was the fifth hurricane of the season, but never attained major hurricane status. Isaac struck Newfoundland, bringing tropical-storm force winds there. Afterwards, Isaac merged with a newly-formed baroclinic low off the East Coast of the United States. The merged system was forecast to move towards Greenland and Great Britain. Damages are unknown with Isaac, although they were minimal at best. There are no reported fatalities with Isaac.
|Formation||September 27, 2006|
|Dissipation||October 3, 2006|
|Highest winds||85 mph|
|Lowest pressure||985 mbar|
Isaac originated from a tropical wave that exited the coast of Africa on September 18. An area of disturbed weather began interacting with the tropical wave, with deep convection increasing on September 23. As convection began to organize, the first Dvorak classifications began on the system. Despite this, the NHC did not classify the system as a tropical depression until September 27. On September 28, the depression intensified into Tropical Storm Isaac, the ninth tropical storm of the 2006 Atlantic hurricane season. Isaac headed northwest in the open Atlantic Ocean, struggling to intensify very much because of the presence of cooler waters that were created by the passage of hurricanes Gordon and Helene earlier in the season. However, as Isaac began to head west-northwest, it took on subtropical characteristics, with its convection deepening. Wind shear over the system weakened, as Isaac headed away from the cooler waters left behind by Gordon and Helene, and its inner core began redeveloping, and Isaac became a hurricane on September 30. After becoming a hurricane, Isaac intensified slightly further to reach a peak strength as an 85 mph Category 1 hurricane while it was near Bermuda.
After peaking, Isaac weakened to an 80 mph hurricane, with its minimum central pressure remaining at 985 mb, what it was at its peak intensity of 85 mph. Isaac encountered cooler waters on its way to Newfoundland on October 1, thus Isaac weakened to a tropical storm on October 2. On October 2, Isaac made landfall on the Avalon Peninsula as a minimal tropical storm, while maintaining a cyclonic structure, as well as deep convection. Shortly afterwards, Isaac transitioned into an extratropical storm and then merged with a larger extratropical system on October 3 off the coast of the Avalon Peninsula.
On October 1, a Tropical Storm Watch was issued for the Avalon Peninsula. On October 2, the Tropical Storm Watch was changed to a Tropical Storm Warning. Also, a Tropical Storm Watch was issued for the Burin and Bonavista Peninsulas on October 2, due to Isaac's approach. Those warnings were discontinued the same day. The final warning issued because of Isaac was a Tropical Storm Warning for the Avalon Peninsula on October 2.
The Atlantic Storm Prediction Center issued a warning for Prince Edward Island and northern Nova Scotia, telling them to expect 1-2 inches of rain from Isaac on October 1. A hurricane-force wind warning was issued for Laurentian Fan, Newfoundland, and gale and storm-force wind warnings were issued for the eastern portions of the Martime Marine District. Finally, a rainfall warning was issued for southeastern Newfoundland, due to the threat of 40-50 mm rainfall.
In Newfoundland, the strongest winds reported on land were sustained winds of 46 mph, with gusts to 60 mph at Cape Race as Isaac came through the area. At Cape Pine, a wind gust to 47 mph was reported. Because of the small size of Isaac, and also due to its fast foward motion, winds were lighter than that over much of the Avalon Peninsula. In St. John's, Isaac produced a wind gust to 33 mph. At Cape Race, rainfall amounts peaked at 1 inch, 0.4" at St. John's, and 0.75" at Cape Pine, due to Isaac losing its moisture.
Canadian buoy 44138 reported wind gusts as high as 56 knots, with sustained winds at 50 knots. During Isaac's transition into an extratropical storm on October 3, three oil platforms reported 48-56 knot winds east-southeast of Isaac's center of circulation. Also, the buoy reported waves as high as 5 meters.
Lack of Retirement
Due to its minimal effects, the name Isaac was not retired in the Spring of 2007, and is on the list for names to be used in the 2012 Atlantic hurricane season.