Its weakening trend was slower than usual due to warmer than usual water temperatures, and by late on September 10 Erin weakened to a Category 2 hurricane. Multiple short-wave troughs weakened the western portion of the subtropical ridge, and on September 11, Erin decelerated as it turned to the east.
Erin's decline was slower than usual due to warmer water temperatures, and by late September 10, it had weakened to a Category 2 hurricane. Short-wave troughs affected the western part of the subtropical ridge, and on September 11, Erin slowed down as it moved eastward.