Olivia Enters Central Pacific Basin as Category 1 Hurricane

Olivia, forecast track (9.8.18) 5 p.m. HST. PC: NOAA/NHC

As of 5 p.m., Olivia has weakened to a Category 1 (74-95 mph) hurricane with sustained winds near 80 mph, and the system is moving toward the west near 16 mph.

According to the Central Pacific Hurricane Center, the latest 5 p.m. forecast “brings the center of Olivia over the main Hawaiian Islands between 72 and 96 hours. A more westward motion is expected to resume after Olivia’s passage through the islands, as the upper ridge retreats westward and the circulation center becomes increasingly steered by the lower level trades.”

According to the latest forecast discussion, the CPHC says Olivia has already traversed the coolest water it was going to encounter, but ocean temperatures will stay below 27C (80.6F) until Olivia gets close to the islands. According to NASA, sea surface temperatures must be 82 degrees Fahrenheit (F) or warmer for tropical cyclone formation and sustenance.

“This should allow Olivia to only very slowly weaken or maintain intensity through the next 24 to 48 hours. Shear should begin to gradually increase over Olivia after 48 hours, leading to a slow weakening trend, but likely not soon enough to prevent some significant impacts to the main Hawaiian Islands,” according to the CPHC.

Olivia satellite imagery 9.8.18 5 p.m. HST. PC: NOAA/NHC

Olivia has now entered the Central Pacific Basin after crossing 140W longitude. Updates are now coming from the Central Pacific Hurricane Center.

At 5 p.m. HST on Saturday, Sept. 8, 2018, the center of Hurricane Olivia was located about 930 miles E of Hilo; 995 miles E of Kailua-Kona; 985 miles E of South Point; 980 miles E of Hāna; 1010 miles E of Kahului; 1045 miles E of Kaunakakai; 1040 miles E of Lānaʻi City; 1100 miles E of Honolulu (near latitude 21.8 North, longitude 140.8 West).

Olivia is expected to continue on its path with some slowing in forward speed through Monday. A turn
toward the WSW is expected by Tuesday. The CPHC reports that little change in strength is forecast during the next two days, with gradual weakening expected afterward.

Forecasters with the Central Pacific Hurricane Center say Olivia will be near the main Hawaiian Islands later Tuesday.

Olivia satellite imagery 9.8.18 5 p.m. HST. PC: NOAA/NHC

Hurricane-force winds extend outward up to 30 miles from the center and tropical-storm-force winds extend outward up to 115 miles, according to the CPHC.

Forecasters continue to monitor Olivia’s intensity, speed and track.

The latest forecast track shows the center of the system tracking over the south east edge of Maui as a Tropical Storm on Tuesday evening; however the long-term forecast continues to undergo revisions as new data is evaluated with each update. It remains too early to determine specific impacts on island weather at this time.

In today’s area synopsis, the National Weather Service says, “Light and variable winds will continue through Monday as Tropical Storm Norman tracks northward and away from the state. Clouds and showers will favor interior and leeward locations each afternoon through Monday with a just a few light showers expected elsewhere. The latest forecast for Hurricane Olivia has it approaching the area from the east early next week, then quickly move through portions of the island chain during the middle part of next week.”

Tropical Storm – winds 39-73 mph (34-63 kt)
Category 1 – winds 74-95 mph (64-82 kt)
Category 2 – winds 96-110 mph (83-95 kt)
Category 3 – winds 111-129 mph (96-112 kt)
Category 4 – winds 130-156 mph (113-136 kt)
Category 5 – winds 157 mph and up (137+ kt)