Hurricane expert William Gray downgraded his 2007 Atlantic storms forecast slightly Tuesday, but he still predicted above-average activity for the remaining three months of the season, with six more hurricanes, three of them major.

A combination of a weak La Nina and low pressure readings in the Atlantic usually indicate an active season, said forecaster Phil Klotzbach, a member of Gray’s team at Colorado State University.

The first two months of the Atlantic season, June and July, had average activity with two named storms but no hurricanes. August was about average, with one hurricane, Dean, which grew into a powerful Category 5 storm before hitting Central America.

Gray has been forecasting hurricanes for more than two decades, and his predictions are watched closely by emergency responders and others in coastal areas.

Before the start of the June-through-November Atlantic hurricane season, his team forecast 17 named storms and nine hurricanes. The team revised that forecast slightly downward in early August to 15 named storms and eight hurricanes.