The NHC said Olivia will weaken further over the weekend, and possibly downgrade to a tropical storm by Tuesday.
Meanwhile closer to Hawaii, Tropical Storm Norman continued to move north-northwest away from the islands.
Hurricane Olivia, a storm with sustained winds of 80 miles per hour, is churning toward Hawaii and could affect the island chain as early as Tuesday evening. A west-southwest motion is expected to begin later tonight. It'll remain over open water as we roll through the next few days, but it's forecast to become a major hurricane by Monday night.
The storm was the second-wettest tropical system to affect the United States and the wettest tropical system on record in Hawaii, surpassing Hurricane Hiki in 1950.More news: Woods, Mickelson, DeChambeau selected to U.S. Ryder Cup team
The hurricane is now forecast to pass the south of Hawaii on Wednesday. "Some gradual weakening is possible on Tuesday, but Olivia will likely remain a threat to the Hawaiian Islands next week", the hurricane center said. The cyclone was moving to the west at 12 miles per hour. The proclamation declares the counties of Hawai'i, Maui, Kalawao, Kaua'i and the City and County of Honolulu disaster areas for the objective of implementing emergency management functions.
This news about Hurricane Olivia comes just weeks after Hurricane Lane brought 3-4 feet of rainfall to parts of Hawaii.
It's expected to be a tropical storm by the time it makes landfall. As NPR's Bill Chappell reported, the town of Mountain View on the Big Island recorded 51.53 inches of rain as a result of Lane, the third-highest total ever measured from a US storm. Gov. David Ige said "We're monitoring this storm closely and taking steps now to ensure that we're prepared for its impacts to the state".