U.S. forecaster sees four September hurricanes

By Tom Brown

MIAMI (Reuters) - "Well above-average" Atlantic hurricane activity is expected in September with four hurricanes, including two that will become major storms, the noted Colorado State University research team said on Tuesday.

"We predict that September will be quite active based on climate signals through August," said hurricane season forecasting pioneer Dr. Bill Gray, founder of the CSU research team.

The team said it expected storm activity this month to be a little shy of twice the normal for a September, citing warmer than normal sea surface temperatures, no sign of an El Nino weather phenomenon in the Pacific and near-record low sea level pressures in the tropical Atlantic.

The team issued its last seasonal outlook in August, when it predicted there would be 17 tropical storms, nine of which would become hurricanes with top winds of at least 74 mph (119 km per hour). It did not update its forecast for the full season on Tuesday.

Atlantic storm seasons start on June 1 and end November 30 and usually peak on September 10. They have an average of 10 tropical storms, six of which strengthen into hurricanes.

The record-busting 2005 season, which included deadly Hurricane Katrina, had 28 storms.

Hurricane Hanna, which developed on Monday near the Bahamas, is the fourth hurricane of the season. The season, which has seen 10 named storms, also produced Hurricane Gustav, which was dissipating after lashing Louisiana with high winds and storm surge.

Of the four hurricanes the CSU team is predicting for September, it said two were likely to be intense or "major" with top sustained winds in excess of 111 mph (170 kph).

Major hurricanes are those that are ranked from Category 3 to Category 5 on the five-step Saffir-Simpson intensity scale.

(Editing by Michael Christie and Bill Trott)