The National Hurricane Center is mentioning in its Tropical Weather Outlook the potential for development of a tropical wave still over Africa. In my 34 years at the NHC, I don’t recall ever mentioning a tropical wave before it emerged from the coast of Africa. We certainly monitored these disturbances by satellite and surface/upper air data, but these systems come off the coast every three to four days and we were never smart enough to know which ones would develop. The science has improved and several of the global models are currently showing development of this wave about to emerge from Africa. The forecasters have enough confidence in these models to at least mention the potential for tropical cyclone development. Time will tell if the models are correct.
Even if this tropical wave does not develop, July has been an extremely busy month. Three named storms have formed in July; Bertha was a named storm for a little over 17 days which is the longest a storm has been tracked in the Atlantic during the month of July; and the Accumulated Cyclone Energy (ACE) Index (defined mathematically as the sum of the squares of the maximum sustained wind speed through the life of each tropical/subtropical storm or hurricane) is around 30 units and continuing to increase with Cristobal and Dolly. I always liked the ACE index because it is a more robust measure of tropical cyclone activity than numbers of storms and hurricanes. See my blog from August 13, 2007.
The current ACE units give 2008 the fourth highest ACE on record (so far) for the month of July. The three years that have had July ACE values higher than this year are 2005, 1916 and 1933. All three of those years ended up being very active based on the season ACE. And all three of those years had at least five major hurricanes.
Of course, what really counts is where the hurricanes make landfall and how strong they are at landfall. And no one can accurately forecast landfalls and intensity with a long lead time. Still, this active July would seem to suggest that the overall activity for the basin will be above average and is another reason to dust off the hurricane plans.