South Atlantic tropical cyclone
From Wikipedia, the free encyclopedia
A South Atlantic tropical cyclone is an unusual weather event. Strong wind shear (which disrupts cyclone formation) and a lack of weather disturbances favorable for tropical cyclone development make any hurricane-strength cyclones extremely rare. If a "hurricane season" were to be demarcated in the South Atlantic, it would most likely be the opposite of the North Atlantic season, from December to May with mid-March being the peak when the oceans are warmest in the Southern Hemisphere.
Below is a list of known South Atlantic tropical cyclones.
Contents |
[edit] Cyclone Catarina
- Main article: Cyclone Catarina
Cyclone (or Hurricane) Catarina was an extraordinarily rare tropical cyclone, forming in the southern Atlantic Ocean in March 2004. Just after becoming a hurricane, it hit the southern coast of Brazil on the evening of March 28, with winds estimated near 160 km/h (100 mph), making it a Category 2 storm on the Saffir-Simpson Hurricane Scale.
This event is considered by meteorologists to be a once-in-a-lifetime occurrence (though some believe climate change may make them more common); as it was mentioned in the film An Inconvenient Truth.
[edit] Other known South Atlantic tropical cyclones
[edit] Angola tropical cyclone of 1991
On April 10, 1991, what was either a strong tropical depression or a weak tropical storm formed in the eastern South Atlantic, recorded by weather satellites off the coast of Angola. It reached a peak on the 13th, and dissipated two days later, drifting west-southwestward from where it formed. Of the few South Atlantic tropical cyclones that have existed, this was the only one in the eastern Atlantic. This was also the first South Atlantic tropical cyclone ever observed.
[edit] Tropical cyclone of January 2004
A small area of convection developed on a trough of low pressure in mid January off Brazil. It organized and appeared to become a tropical depression on January 18th. The next morning, it had a small CDO and well-defined bands, and the system, either a weak tropical storm or a strong tropical depression, likely reached its peak. Located 150 nm southeast of Salvador, Brazil, it weakened as upper level shear, typical for the basin, prevailed. The depression moved inland on the 20th as a circulation devoid of convection, and dissipated the next day over Brazil, where it caused heavy rains and flooding. This would mark the first time in recorded history that two tropical cyclones (Catarina and the January storm) have been seen during the same year in the South Atlantic, and may be considered to make up the 2003-04 South Atlantic hurricane season.
[edit] Possible tropical/subtropical cyclones of 2006
During what could be considered the 2005-06 South Atlantic hurricane season, two systems with tropical or subtropical characteristics were recorded, but neither directly affected land.
On February 23, a tropical depression formed for a few hours, but was quickly sheared apart by strong upper-level winds. The system had a closed circulation, and winds of up to 35 mph (according to the QuikSCAT satellite). The system formed near 29S 36W, about 600 miles southeast of Rio de Janeiro, Brazil, over waters of about 27 °C. [1]
On March 15, another disturbance formed from the remains of a cold-core low, which sat over warm waters of 27 °C long enough to start acquiring tropical characteristics. This system had at least two recorded bursts of convection, one near the center of circulation, but both were swept clear by upper-level winds. Its southward trajectory (parallel to the coast) over cooler waters, coupled with interaction with a cold front served to prevent this system from developing further. [2]
[edit] See also
[edit] References
- ^ http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=309&tstamp=200602 Meteorologist Jeff Masters' Blog
- ^ http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=320&tstamp=200603 Meteorologist Jeff Masters' Blog
