Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 3:05 PM GMT on March 06, 2010
An area of disturbed weather off the coast of Brazil, near 17S 38W, has changed little over the past day. It has a slight potential to develop into subtropical or tropical depression early next week. Satellite winds estimates from the WindSat instrument show an elongated area of converging winds, but no organized surface circulation. Satellite loops show little organization to the cloud pattern, and only limited heavy thunderstorm activity. Wind shear over the region is about 20 knots, which is rather high, and should keep any development slow. Sea surface temperatures are about 28°C, about 1°C above average, and plenty warm enough to support a tropical storm. The system is small, and this will limit its potential to become a tropical cyclone.
Figure 1. Morning visible satellite image of the Brazilian disturbance.
The ECMWF, UKMET, and NOGAPS models have backed off on their predictions of development a fair amount in recent runs. Phase space diagrams from Florida State University show that this storm has less of a warm core than before, meaning it would probably be classifiable as a subtropical storm if it gets more organized and achieves surface wind speeds of at least 39 mph. The system does not appear to be a threat to bring heavy rains to the Brazilian coast. I give this storm a low (< 30% chance) of developing into a tropical or subtropical depression by Monday. The storm should move to the south or southeast away from the coast. Only six known tropical or subtropical cyclones have formed in the South Atlantic. Tropical cyclones rarely form in the South Atlantic Ocean due to strong upper-level wind shear, cool water temperatures, and the lack of an initial disturbance to get things spinning (no African waves or Intertropical Convergence Zone exist in the proper locations in the South Atlantic to help spawn tropical storms).
Portlight continues relief efforts in Haiti
Portlight and the Liberty Schooner are sponsoring "The Haitian Food Voyage," shipping 10,000 pounds of rice to Haiti. Thanks to your generous donations, the mission is set to sail to Haiti during the second week of April. Please visit the Portlight.org blog to learn more and to donate to this worthy cause.
Figure 2. R.Richard Lumarque, Portlight's on-site coordinator in Haiti, assists a woman who has just received a new walker from Portlight. The woman was injured when a 3-story building collapsed on her during the January earthquake.
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