Bursts of tropical cyclone development in late starting seasons
August 15, 2009
While we wait for the next package of advisories from the National Hurricane Center, which will introduce Tropical Storm Bill, I would like to point out a similarity of the past couple of days to the first two storms of 1949. It appears that like Ana and Bill, the first two storms of 1949 developed from consecutive tropical waves. The Hovmuller diagram below shows the progression (as well as the development of Hurricane Guillermo in the Pacific):
The past couple of runs of the GFS model suggest that the streak is going to be three in a row as it forecasts development of this wave, currently exiting Africa.
The late starting and fairly quiet 1987 season also featured consecutive wave development. The fairly late starting but busier 1980 season had a three storm run, though the last tropical storm of the bunch came from the first wave.