Frank Lepore, spokesperson for the National Hurricane Center at National Oceanic and Atmospheric Administration, said the five-day projections on the movement and strength of tropical storms and hurricanes affecting the United States would begin June 1.

"This goes back to a 1999 request by the U.S. Navy for five-day forecasts, and the National Weather Service ran this forecast in the background, if you will, during the 2001 and 2002 hurricane seasons," Mr. Lepore said.

Data from the 2001 and 2002 seasons indicate the five-day track forecast will be as accurate as the three-day forecast was 15 years ago, he noted.

"For the general public, which would be more germane to the insurance industry, the five-day forecasts would serve as a heads-up, an additional two days of planning and preparing. It would be an increased awareness for the general public," Mr. Lepore said.

He added that those two extra days could be especially helpful to those who don't have much experience preparing for storms and hurricanes--new residents who recently moved to Florida or other southern states, for example.

Extra days to prepare for impending hurricanes would also benefit insurers, who lose hundreds of millions of dollars every year from hurricane-covered losses in the United States.

In its recent annual study of natural-catastrophe trends, the Munich, Germany-based reinsurer Munich Re said significant natural-catastrophe events in the United States last year included tornadoes in April, which caused $1.6 billion in overall insured losses, and storms in November, which resulted in $460 million losses.