HONOLULU - Authorities in Hawaii have opened emergency shelters to prepare for a tropical storm that's expected to bring up to 15 inches of rain and sustained winds of 50 miles per hour. The National Weather Service says Tropical Storm Flossie has weakened into Monday morning but will remain a significant threat for up to at least three days. The storm was about 160 miles east of Hilo Monday morning and is moving west at about 16 mph. The tropical storm is expected to hit the Big Island by midday Monday, bringing 6 to 10 inches of rain in many areas and up to 15 inches in others. Eighteen-foot waves also are possible. Eight emergency shelters have opened.