Kort artikeltje over de tropische cycloon voor de Braziliaanse kust.
Wouter
The unnamed South Atlantic tropical/subtropical cyclone (90Q) off the coast of Brazil continues to spin slowly out to sea, and is not a threat to any land areas. The storm, just the 7th tropical or subtropical cyclone on record in the South Atlantic, has a well-defined surface circulation, top wind speeds near minimum tropical storm force (40 mph), a surface pressure near 1004 mb, and a modest amount of heavy thunderstorm activity on its south side. Strong upper-level winds from the northeast are creating about 20 knots of wind shear over the storm, keeping the northeast side of the circulation exposed to view. Sea surface temperatures are about 25.5°C, which is about 1°C below what is typically needed to support a tropical storm. The storm is headed southeastward out to sea at about 10 mph, and will lose its tropical characteristics and get absorbed by a frontal system by Saturday.
When the storm formed two days ago, it began as a cold-cored system aloft, with a warm core at the surface, making it a hybrid subtropical storm. Yesterday, the entire core of the storm warmed enough for it to be worthy of consideration for tropical storm status. Tropical and subtropical storms are so rare in the South Atlantic that there is no official naming of depressions or storms done. The cyclone had top winds of at least 35 mph this morning at 7am EST as seen on an ASCAT pass, and satellite estimates of the storm's intensity have held steady at 40 mph (minimum subtropical storms strength) for the past 12 hours. ASCAT winds tend to be biased a little low at this speed range, so 40 mph--minimum tropical storm strength--is probably the best estimate of the winds. Phase space diagrams from Florida State University are showing that the storm has grown less tropical (warm-cored) in nature over the past 12 hours. When compared to similar systems that have developed in the North Atlantic that have been named, I definitely think today's storm deserves a name. The World Meteorological Organization should act to come up with a list of names for the South Atlantic, since these storms have the potential to cause considerable death and destruction along the South American coast, and deserve to receive the extra attention naming would provide.
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