Extended range hurricane forecast bodes ill for 2010

by Sail-World Cruising on 1 May 2010 As if the Gulf of Mexico didn't have enough problems right now, atmosphere scientists from the Department of Atmospheric Science at Colorado State University have issued an extended range forecast which heralds an above average activity for the 2010 Atlantic hurricane season.

Research scientist Philip Klotzbach and Professor Emeritus of Atmosphere Science William Gray have now increased their seasonal forecast from the mid-point of their initial early December prediction.

They pin the cause on two factors: First is an anomalous warming of the Atlantic tropical sea surface temperatures, and the second is that they are now more confident that the current El Nino will weaken.

They resultant forecast is ominous for the Caribbean: 'We anticipate an above-average probability of United States and Caribbean major hurricane landfall."

Why issue extended-range forecasts for seasonal hurricane activity?

As well as issuing the forecast, the two researchers explain why they issue these forecasts:

'We are frequently asked this question. Our answer is that it is possible to say something about the probability of the coming year’s hurricane activity which is superior to climatology. The Atlantic basin has the largest year-to-year variability of any of the global tropical cyclone basins. People are curious to know how active the upcoming season is likely to be, particularly if you can show hindcast skill improvement over climatology for many past years.

'Everyone should realize that it is impossible to precisely predict this season’s hurricane activity in early April. There is, however, much curiosity as to how global ocean and atmosphere features are presently arranged as regards to the probability of an active or inactive hurricane season for the coming season.

'Our early April statistical forecast methodology shows strong evidence over 58 past years that significant improvement over climatology can be attained. We would never issue a seasonal hurricane forecast unless we had a statistical model developed over a long hindcast period which showed significant skill over climatology.

'We issue these forecasts to satisfy the curiosity of the general public and to bring attention to the hurricane problem. There is a general interest in knowing what the odds are for an active or inactive season. One must remember that our forecasts are based on the premise that those global oceanic and atmospheric conditions which preceded comparatively active or inactive hurricane seasons in the past provide meaningful information about similar trends in future seasons.

'This is not always true for individual seasons. It is also important that the reader appreciate that these seasonal forecasts are based on statistical schemes which, owing to their intrinsically probabilistic nature, will fail in some years.

'Moreover, these forecasts do not specifically predict where within the Atlantic basin these storms will strike. The probability of landfall for any one location along the coast is very low and reflects the fact that, in any one season, most U.S. coastal areas will not feel the effects of a hurricane no matter how active the individual season is.'