Posted by: JeffMasters,10:01 AM EDT on July 29, 2009
There are no threat areas in the Atlantic worthy of mention today, but the GFS model is pointing to the possibility that a tropical wave off the coast of Africa could develop this weekend. However, none of the other models are predicting this, and the previous run of the GFS model did not develop anything. So, any development in the tropics this week looks unlikely. The hurricane season of 2009 is off to a slow start, and it will be August before our first named storm appears. How does this late-starting hurricane season compare to other years?
Well, the first named storm of the year didn't occur until August in ten of the past fifty years (20%). Only two of these ten seasons ended up with more hurricanes than average (seven or greater). The record for the latest starting hurricane season since 1851 was set in 1914, when the only storm of the season formed on September 15. The year 1941 was also late starting, with the season's first storm arriving on September 11. Of course, we didn't have satellites back then, so it's a good bet there were storms earlier in these seasons that got missed. However, there's a good possibility that 1914 really did have only one storm. A re-analysis of the hurricane activity in the decade 1911-1920 (Landsea et al., 2008) found 1.3 missing tropical cyclones per year, thanks to the inclusion of a new database of ship weather reports called COADS. However, 1914 was not one of those years. Various authors have estimated that we missed an average of between one and three tropical cyclones per year during that time period, so it is quite possible 1914 had only one storm.
Figure 1. The hurricane season of 1914 featured only one tropical storm, and was the latest-starting hurricane season on record (September 15).

The latest dates for the first named storm of the season in the recent past, followed by the number of named storms, hurricanes, and intense hurricanes that year are:
2004 (August 1) 15,9,6
2000 (August 4) 15,8,3
1988 (August 7) 12,6,3
1987 (August 9) 7,3,1
1984 (August 18) 13,5,1
1983 (August 15) 4,2,1
1977 (August 30) 6,5,1
1967 (August 30) 8,6,2
1963 (August 2) 9,6,2
1962 (August 22) 5,3,1
For comparison, an average Atlantic hurricane season has 10 named storms, 6 hurricanes, and 2 intense hurricanes. So, it is a good bet that 2009 will be a below-average season. We have two experimental seasonal forecast models that agree with this idea--the UKMET Glosea models, which is forecasting only six named storms this year, and the newly-released Florida State University Center for Ocean-Atmospheric Prediction Studies (COAPS) model, which is forecasting eight named storms and four hurricanes. The Phil Klotzbach/Bill Gray Colorado State University seasonal forecast updates on Tuesday August 4, and it will be interesting to see what forecast numbers they come up with.