Hurricane Iselle strengthened into a major category three hurricane over the Pacific Ocean on early Sunday morning, and the tropical cyclone is now forecast to hit the Hawaiian islands later next week as a tropical storm, U.S. forecasters said. Forecasters at the U.S. National Hurricane Center (NHC) have been following the weather system since last Tuesday when it emerged as an area of low pressure far off the southwestern coast of Mexico.
It quickly became better organized on Thursday and strengthened into a tropical storm that same day, after which it became a hurricane on late Friday. Iselle continued to strengthen rapidly over the weekend, reaching category three status on the five-step Saffir-Simpson scale of intensity with maximum sustained winds near 115 miles (185 kilometers) per hour on early Sunday. Iselle may strengthen further throughout Sunday, but is unlikely to reach category four status. "It hasn`t been particularly steady, but Iselle continues on a gradual strengthening trend. The eye has cleared out in infrared satellite imagery, and the overall presentation has become a little more symmetric," said NHC hurricane specialist Robbie Berg. "The NHC forecast maintains Iselle at 100 knots for the next 12 hours and then only gradually weakens it through 48 hours, but given the hurricane`s history, I can`t rule out some additional strengthening in the short term." Forecasters expect Iselle will weaken to a category two hurricane on early Monday, and will continue to gradually weaken through Wednesday, when the tropical cyclone is expected to weaken to a tropical storm. Computer models strongly indicate Iselle will make landfall on the Hawaiian islands on Friday morning, but any foreseen changes in the coming days could change that. As of 8 a.m. PDT (1500 GMT) on Sunday, the eye of Hurricane Iselle was located about 1,495 miles (2,405 kilometers) southeast of Hilo on the island of Hawaii. It is moving toward the west at a speed near 10 miles (17 kilometers) per hour, but this motion is expected to change over the next few days, taking it on a path to Hawaii. Tropical storms and hurricanes are relatively uncommon for the Hawaiian islands, although a weak Tropical Storm Flossie affected Hawaii in July 2013, causing only minor damage. The last time a tropical cyclone caused casualties in Hawaii was in 1992 when major Category four hurricane Iniki made landfall there, killing six people. Iselle is the ninth tropical cyclone of the Eastern Pacific hurricane season, which officially began on May 15. According to figures released in May, NOAA`s Climate Prediction Center is expecting an above-normal season in the Eastern Pacific basin this year. The outlook calls for 14 to 20 named storms, with 7 to 11 becoming hurricanes and 3 to 6 of them expected to become a major hurricane (category 3 or higher). An average Eastern Pacific hurricane season produces 15 to 16 named storms, with eight to nine becoming hurricanes and four becoming major hurricanes. The Eastern Pacific hurricane season runs from May 15 through November 30, with peak activity from July through September.