Florida State scientists unveil new seasonal hurricane forecasting model

Jill Elish in Florida State University News: Scientists at The Florida State University's Center for Ocean-Atmospheric Prediction Studies (COAPS) have developed a new computer model that they hope will predict with unprecedented accuracy how many hurricanes will occur in a given season.

After about five years developing and assessing the model, Associate Scholar Scientist Tim LaRow and his COAPS colleagues are putting the system to the test this year with their first-ever hurricane forecast. The COAPS model is one of only a handful of so-called "dynamical models" in the world being used to study seasonal hurricane activity.

The COAPS model has predicted a below-average season in the Atlantic Ocean, with a mean of eight named storms and four hurricanes based partially on emerging El Nino conditions. During an El Nino, the warmer ocean temperatures in the tropical eastern Pacific tend to suppress hurricane activity in the Atlantic. The historical seasonal average is 11 tropical storms and six hurricanes.

…Before making this year's prediction, they used the model to perform 20 years of re-forecasts, or hindcasts, using the sea surface temperatures determined by the National Oceanic and Atmospheric Administration on June 1 of every year from 1986 to 2005. They found a very high correlation between the model's predictions of the number and intensity of tropical cyclones and what actually occurred during those years.

In addition, the model outperformed many statistical and other dynamical models, LaRow said. Statistical models use statistical relationships between oceanic and atmospheric variables to make a forecast, while dynamical models, such as the COAPS model, require major computing resources in order to make trillions of calculations using the equations of motion along with the best physical understanding of the atmosphere….

The tracks of all 2008 Caribbean hurricanes