A TROPICAL SYSTEM THAT WON’T QUIT

30 July 2010

   Around 28/29 July 2010 an cell of low pressure generating intense rain and storms developed off the east coast of Florida some 150 miles from St. Augustine. While this weather system initially showed little movement it eventually starting moving toward the west by southwest. In early August the system came onshore over Florida moving toward the southwest while generating intense rain over central Florida and eventually South Florida.

The system then moved into the Florida straits and began affecting Cuba and the Florida keys to then turn north by northwest as it moved into the warmer waters of the Gulf of Mexico. The system became tropical depression #5 of the 2010 Atlantic Hurricane season some 100 miles to the west of Naples and then picked up speed aiming for the Luisiana coast.  Tropical depression #5 was downgraded to a low-pressure system before making landfall while it affected the oil-spill cleanup/rescue operations in the Gulf.

7 August 2010
9 August 2010
12 August 2010

 After the system came onshore in Luisiana on 11/12 August, generating plenty of rain and storms, and as it continue moving inland it was expected to weaken and eventually dissipate. Hpwever quite the contraty has happened, the system was fueled by other systems in the area, it has strengthened, and it began to be pushed back south toward the super-warm waters of the Gulf of Mexico until earlier today 15 August 2010 ir has emerged back over the Gulf off the coast of Alabama with plenty of rain and storms. As it continues to move southward farther over the Gulf warm waters the system is strengthening and encountering an environment that may favor further development and event tropical cyclone formation within the next 24 – 48 hours.  The NOAA Tropical Prediction Center/National Hurricane Center were giving this system a 30% chance of tropical cyclone formation within the next 48 hours as of 16 August 2010 at 2:00 P.M. EST. 

Tropical Outlook 15 August 2010 at 2:00 P.M. EST

2010 vs 2009 Atlantic and Pacific Water Temperature

Sea surface water temperature is a contributor, together with several other factors, to hurricane formation (cyclogenesis); because of this satellites use remote-sensing filters to measure surface water temperature over the ocean. Regarding sea surface water temperature it is important to know that in some cases it is not only the water temperature along the path of a tropical wave, but also that of waters thousand of miles away, which  may contribute to or deter the formation of hurricanes.

Sea surface temperature 20 August 2009
Sea surface temperature 12 August 2010

A good example of this is the Atlantic basin where hurricane formation is affected by the temperature of the water in the eastern Pacific ocean off the coast of Peru and Ecuador, and whether there is an El Nino (warmer water) or La Nina (cooler waters) or the waters are ‘normal’ in temperature with respect to historical average. These factors are taken into account by those who issue long-term forecasts prior to the start of hurricane season.

A good example of that long-distance water temperature relationship is illustrated by the two images, one from August 2009 and the other from August 2010, taken about one year apart showing how the surface water temperature in the eastern Pacific and the Atlantic basin have changed over that period.

The picture on the left shows than in August of 2009 the eastern Pacific was quite warm, as indicated by the bright and deep dark brown colors off the coast of Central America, while in the Atlantic about 50% of the Gulf of Mexico had waters above 86 F. By contrast, the picture of the right shows than in August of 2010 the waters in the Atlantic are much warmer, and about 90% of the Gulf waters are above 86 F as well as a good portion of the Caribbean to the south of Cuba; at the same time waters in the eastern Pacific, especially off the coast of Peru and Ecuador are much cooler than in 2009 signaling the onset of a La Nina event. Reflecting these variations in sea surface temperatures on the eastern Pacific and the Atlantic from a year ago, the forecast for the 2010 Atlantic hurricane season is much more active than in 2009.