Brian McNoldy, a meteorologist tracking Atlantic Ocean hurricanes at Colorado State University, just distributed this note from Phil Klotzbach, a colleague, about the unusual storminess in the Atlantic and Caribbean at the moment:
With Karl becoming a hurricane, we have three hurricanes at the same time. This is a pretty rare occurrence. The only other years that this has occurred are 1893, 1926, 1950, 1961, 1967, 1980, 1995, and 1998. 1998 even had four hurricanes at the same time!
I’ve sent a query to some hurricane researchers to get a bit more on what, besides warm sea temperatures, makes conditions this ripe for powerful tropical storms. McNoldy said the conditions are ripe because we’re precisely in the middle of hurricane season and there’s little wind shear, a condition in which layers of air at different altitudes move at different speeds and which tends to break up hurricanes. More reactions will be added as they come in. In the meantime, keep a weather eye on the Web site of the National Hurricane Center and Kerry Emanuel’s page at the Massachusetts Institute of Technology, which collects a variety of forecasts of storm strengths and tracks.