Hurricane season officially begins June 1 but sometimes a tropical storm forms before then. Since records began in 1851 there have been 23 seasons that have had storms prior to June 1. 2012 had two such early arrivals of Tropical Storm Alberto off the coast of the Carolinas, and Tropical Storm Beryl near the Georgia and Florida border.
The Atlantic basin hurricane season of 2012 forecast released April 4 by the Colorado State University Department of Atmospheric Science from Dr. Philip J. Klotzbach and Dr. William Gray predicts reduced activity for 2012 compared to 1981-2010, and below-average probability of a major hurricane landfall along the US coastline and in the Caribbean.
“The tropical Atlantic has anomalously cooled over the past several months, and it appears that the chances of an El Niño event this summer and fall are relatively high.
The forecast is based on a new extended-range early June statistical prediction scheme that utilizes 29 years of past data.
Coastal residents are reminded that it only takes one hurricane making landfall to make it an active season for them, and they need to prepare the same for every season, regardless of how much activity is predicted.”
|Atlantic Hurricane Season||April 2012
|1981 – 2010
|Named storms (>35mph)||10||12|
|Major hurricanes (>111mph)||2||2|
|US landfall likelihood||42%||52%|
|Gulf Coast landfall||24%||30%|
The probability of Florida being hit by a major (Cat 3-4-5) hurricane this year is 16% which is less than the yearly climatological average of 21%.
These speculations that hurricane intensity has increased due to CO2 increases have been given much media attention; however, we believe that they are not valid, given current observational data. Gray (2011) goes into extensive detail describing why the relationship between increased CO2 and increased hurricane activity may not be valid.
There has, however, been a large increase in Atlantic basin major hurricane activity in the last seventeen years (since 1995) in comparison with the prior 17-year period of 1978- 1994 (Figure 16) as well as the prior quarter-century period of 1970-1994. It has been tempting for many who do not have a strong background of hurricane information to jump on this recent increase in major hurricane activity as strong evidence of a human influence on hurricanes. It should be noted, however, that the last 17-year active major hurricane period of 1995-2011 has not been more active than the earlier 17-year period of 1948-1964 when the Atlantic Ocean circulation conditions were similar to what has been observed during the last 17 years. These earlier active conditions occurred even though atmospheric CO2 amounts were lower during the earlier period.”
“For instance, in the quarter-century period from 1945-1969 when the globe was undergoing a weak cooling trend, the Atlantic basin experienced 80 major (Cat 3-4-5) hurricanes and 201 major hurricane days. By contrast, in a similar 25-year period from 1970-1994 when the globe was undergoing a general warming trend, there were only 38 Atlantic major hurricanes (48% as many) and 63 major hurricane days (31% as many). Atlantic SeaSurfaceTemperatures and hurricane activity do not follow global mean temperature trends.”
Closer to our home here on Anna Maria Island, the historical record of hurricane paths over the last 90 years looks like trending to fewer landfalls, but it takes only one storm to be very destructive, depending on intensity and diameter of its wind field.
“We believe that the Atlantic basin remains in an active hurricane cycle associated with a strong THC (thermohaline circulation). This active cycle is expected to continue for another decade or two at which time we should enter a quieter Atlantic major hurricane period like we experienced during the quarter century periods of 1970-1994 and 1901-1925.”
Seasonal updates of the 2012 Atlantic basin hurricane forecasts will be issued on Friday 1 June, and Friday 3 August.