Hurricane Bill has been downgraded to a category three storm with a warning that it could go back to category four.

The National Hurricane Centre has advised Bermuda that a tropical storm watch could be issued later today.

The Centre’s forecast map showed Bill moving north-northwest and projected to cut between Bermuda and the American east coast.

Forecasters have advised that both areas need to monitor the hurricane's progress as its hurricane force winds extend outward to 85 miles from the centre.

Hurricane Bill's maximum sustained winds are close to 125 miles per hour.