The typhoon is moving over waters with sea surface temperatures above 31 degrees Celsius, around 1 to 3 degrees higher than average. Dolphin is forecast to pass near Iwo Jima and over waters south of the Ogasawara Islands around August 4. The storm is then expected to continue west as a strong typhoon and approach Okinawa's Daito Islands around August 6. The islands are forecast to enter the storm's violent-wind zone, while Okinawa's main island could also face a close approach later. A tropical depression near the Philippines, meanwhile, is now considered less likely to develop into a typhoon.