HONOLULU — Hurricane Guillermo was downgraded to a tropical storm Monday as it continued its course toward the Hawaiian Islands.
According to the NOAA's Central Pacific Hurricane Center in Honolulu, Guillermo was about 565 miles (910 km) away from Hilo, Hawaii, on Monday morning. Its track is expected to take it near or over the islands on Wednesday and Thursday. The storm, currently moving northwest at about 12 mph (19 kmh), is expected to steadily weaken over the next couple of days.
National Weather Service meteorologist Matthew Foster said the storm was downgraded because it is entering a weather environment that is not favorable for tropical cyclones.
The exact track of the storm will dictate which islands are impacted most. Dangerous surf, significant rainfall and high winds are expected, and forecasters warn of the chance of coastal and flash flooding.
However, Foster said the latest models show the storm moving slightly north of the islands.
"Typically what that means is more of the stronger winds and rain will be concentrated over the waters north of the islands," he said. The strongest part of the storm is normally in the northeast sector, Foster said, meaning a northerly track could spare the islands from the worst of the storm.
"The further the northern track it takes the less of a threat flooding will be," he added.
High surf had already begun to affect the islands' east facing shores as large swells from Guillermo move ahead of the storm, Foster said.
"We've already seen some of the forerunners, they arrived yesterday actually" he said of the outer swells that move much faster than the actual storm. "We're expecting surf of 10-to-14 foot faces," he added.
In May, officials predicted there would be more hurricanes than average in the Pacific this year because of warmer ocean water.
Tom Evans, the acting director of the NOAA's Central Pacific Hurricane Center, said the prediction was based largely on current El Nino conditions in the region. El Nino is the warming of the water on the surface of the ocean along the equator, he said, and there are more hurricanes on average during El Nino years.
In 2014, the region saw five hurricanes, which falls within the average of four to five storms per year. The last hurricane to directly hit Hawaii was Iniki in 1992. In 2014, Hurricane Iselle approached the island chain but weakened to a tropical storm just before making landfall.
Guillermo currently has maximum sustained winds near 65 mph (100 kmh). There are no coastal warnings or watches currently in effect, but forecasters say some may be issued for certain portions of the state later Monday.
Meanwhile in the Pacific Ocean west of Hawaii, a typhoon with sustained winds around 100 mph and gusts up to 120 mph slammed into Saipan, Northern Mariana Islands, causing widespread damage.
NOAA's National Weather Service in Guam says the storm moved across Saipan Sunday into Monday and has since strengthened to a super typhoon with winds reaching 180 mph. The storm is headed toward northern Taiwan and could hit there sometime this weekend.
According to the National Weather Service, waves about 30 feet high hit the island as the storm approached.
Follow Caleb Jones: http://twitter.com/CalebAP