While I was away on vacation the Tropical Meteorology Project at Colorado State University released its forecast for the upcoming hurricane season. You may know this as Dr. William Gray’s forecast as touted in the media, but Dr. Phil Klotzbach now heads the project and is the lead scientist. However, it is likely that this will be referred to as Gray’s forecast after the originator of the seasonal hurricane forecast.

Here is the headline that most of you have probably seen in the media. The 2008 Hurricane Season is likely to be well above average. The forecast is for:

15 Named storms (tropical storms and hurricanes)
...........of which
8 will become hurricanes
...........of which
4 will become major hurricanes (category 3, 4, or 5)

All of the major news outlets picked this up and flashed it around the world. However, this was only told part of the story. I have always preferred to go to the source and delve into the science of the forecast. Reading the methodology and research behind the forecast has always been more insightful.

Here are some of the tidbits from the research paper released at the time of the forecast:

1. There is an above-average risk of a major hurricane striking somewhere along the U.S. coast. However, the risk seems to be evenly spit between the East coast and Gulf coast.

2. There is an above-average risk of a major hurricane making landfall in the Caribbean

3. A new set of predictors is being used this year on the April forecast. It has been simplified to a set of 3 predictors instead of 6. This new set seems to have a better correlation with the upcoming season activity.

4. The new predictors indicate that the tropical Atlantic will experience warmer sea-surface temperatures, lower sea-level pressures, and weaker trade winds during the height of the hurricane season. This correlates well with active hurricane seasons and the current indicators actually forecast a hyper-active year. However, this will depend on the current La Nina. It is weakening at present, but there are no indications that El Nino will develop during this hurricane season. This would suppress hurricane activity.

5. The best analog years since 1949 that the group could find were 1950, 1989, 1999, and 2000.

One caveat on the forecast; it simply is an attempt to forecast the activity during the season. It does not and can not forecast where individual storms are going to hit. However, the group is making some progress in accessing the risk of a landfall at different points along the coast. This may be of considerable use to emergency managers in the future.

You can read the entire technical paper for yourself at The Tropical Meteorology Group's Forecasts . Much of this is too technical for non-meteorologists. However, there is an excellent section on the impact of global warming on hurricanes beginning on page 25 of the paper.

This is the 25th year that the Tropical Meteorology Project founded by Dr. William Gray has made seasonal hurricane forecasts. Forecasts prior to 1983 were abysmal failures. However, Dr. Gray demonstrated that by using global and regional predictors successful forecasts could be made. He and others have greatly increased our knowledge of what conditions are necessary for active hurricane seasons. Dr. Gray has also increased our knowledge about the climatology of hurricane seasons and recognized that the activity was cyclical.

Thus, we are now in an active cycle which began in about 1995. The cycles run about 20-30 years. Therefore, don’t be surprise to see above-average hurricane activity through 2020.

I spent part of my vacation in New Orleans which was devastated by Hurricane Katrina. My thoughts and impressions will be the topic of my next blog.