The GOES image above shows Hurricane Igor centered about 500 miles east-northeast of the Leeward Islands and Hurricane Julia centered about 600 miles west-northwest of the Cape Verde Islands. Both hurricanes are currently powerful Category 4 hurricanes on the Saffir-Simpson Hurricane Wind Scale.
According to the National Hurricane Center records, two category 4 hurricanes existing simultaneously in the Atlantic Basin has occurred only one other time since 1900: September 16, 1926 when the Great Miami Hurricane was headed toward the Bahamas and South Florida and Hurricane #4 that was centered about 350 miles east of Cape Hatteras, NC about to recurve to the northeast away from the U.S.
Hurricane Julia becoming a Category 4 hurricane makes the fourth Category 4 so far in this hurricane season. Other Cat 4’s this year include Hurricanes Danielle, Earl, and Igor. Dr. Phil Klotzbach also notes that the historical records show there have been only seven other years with four or more Category 4+5 hurricanes in the Atlantic Basin.
The usual caveats apply such as the intensity of some of this year’s Cat 4’s were estimated by satellite only and the historical records in previous years such as 1926 likely did not have much ground truth either. But the bottom line is that this has been a very active season so far and we still have two and one half months left to go.