The United States' leading storm forecaster has slightly lowered the number of hurricanes expected to form in the Atlantic basin this year.

Colorado State University Professor William Gray is still predicting an above-average hurricane season but he expects only four storms to be classified as major or intense, the Orlando Sentinel reported Friday.

His latest prediction of major or intense storms is one less than Gray and his team forecast in late May.

At that time, Gray predicted a 2007 hurricane season with 17 named storms and nine hurricanes, five of which would be intense, Category 3 or above.

His newest forecast is 15 named storms with eight expected to grow into hurricanes and only four of them ballooning into storms of Category 3 or higher.

So far, only two named tropical storms have turned up this year while a third was subtropical and not counted by Gray's team.

Ninety percent of all hurricanes form in August, September and October.