A typhoon watch means that typhoon conditions are possible within the next 48 hours.
According to the National Weather Service, Tropical Storm Vongfong is strengthening in Northern Pohnpei.
Maximum sustained winds have increased to 50 mph. Vongfong is expected to intensify in the next few days and could become a typhoon Sunday. Storm motion was toward the west-northwest at 15 mph.
At 7 am, the center of Tropical Storm Vongfong was located about 785 miles east-southeast of Saipan and Rota, about 790 miles east-southeast of Tinian and 800 miles east-southeast of Guam.