Postcards from the Orlando Hurricane Conference
I'm in Orlando this week for the 28th Conference on Hurricanes and Tropical Meteorology, sponsored by the American Meteorological Society. The conference, held once every two years, brings together the world's experts on hurricane science. A few snapshots from this morning's talks:
HWRF hurricane model improvements for 2008
Naomi Surgi of NOAA oulined the progress with the new HWRF model, which debuted last year. The HWRF model outperformed the GFDL model in the Atlantic last year for forecasting hurricane tracks. The GFDL had consistently been the best-performing model for forecasting hurricane tracks in recent years, so this is good news. The HWRF model is intended to eventually replace the GFDL model. However, neither the HWRF or GFDL model performed as well as the GFS model last year, so there is room for the HWRF to improve. New for 2008 for the HWRF model is the ability to include real-time Doppler radar data from the NOAA P-3 hurricane hunter aircraft for initialization of the model. There are also upgrades to the equations governing the model's physics, plus improvements in how the model is initialized. These improvements should make for much improved intensity forecasts beyond 48 hours, Dr. Surgi showed. That's good news, because intensity forecasting has shown very little improvement over the past 15 years, despite a near doubling in the improvement in track forecasts.
Dust from Africa
Amato Evan of the University of Wisconsin showed that dust blowing off the coast of Africa has a very strong impact on Sea Surface Temperatures (SSTs) over the tropical Atlantic, amounting to 0.1°C to 1.0°C annually. Dr. Evan showed that most of the warming of tropical Atlantic SSTs in recent years can be explained by variations in the amount of dust coming off the coast of Africa. In particular, 2005 had very little dust, resulting in unusually high SSTs that help lead to the record breaking Hurricane Season of 2005, with its record 28 named storms.
Influence of Gulf Stream Loop Current on Katrina's intensity
Hurricane Katrina explosively deepened when it passed over an unusually far northern extension of the warm Gulf of Mexico Loop Current, and a Warm Core Eddy that had broken off from the Loop Current. Richard Yablonsky and Isaac Ginis of the University of Rhode Island showed that if the Gulf of Mexico Loop Current had been in its normal position, and no Warm Core Eddy had been present, Katrina would have had a pressure more than 20 mb higher and maximum sustained winds at least 20 mph lower. The study was done using the GFDL model.
I'll have more postcards from the Orlando hurricane conference every day this week. One other highlight from this morning: seeing the 5-year old daughter of one the participants entertain herself by setting up a little diorama complete with ponies, unicorns, and fairies on the floor outside of the main session this morning. Who needs Disney World to entertain a kid in Orlando!