SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Warning is in effect for…
Interests in the Northwest Hawaiian Islands should monitor the progress of Olivia.
A Tropical Storm Warning means that tropical storm conditions are expected somewhere in the warning area.
For storm information specific to your area, please monitor products issued by the National Weather Service office in Honolulu Hawaii.
DISCUSSION AND OUTLOOK
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At 11 p.m. HST (0900 UTC), the center of Tropical Storm Olivia was located near latitude 20.8 North, longitude 154.6 West. Olivia is moving toward the west-southwest near 8 mph (13 km/h). A general west-southwest motion and a gradual increase in forward speed is expected overnight as the center of Olivia approaches Maui and the Big Island. After Olivia moves past the islands, a somewhat faster west-southwest motion is expected to resume and continue for the next couple of days.
Maximum sustained winds are near 45 mph (75 km/h) with higher gusts. Some weakening is forecast during the next 48 hour, but Olivia is expected to remain a tropical storm for the next day or so.
Tropical-storm-force winds extend outward up to 90 miles (150 km) from the center, mainly to the north of the center.
The estimated minimum central pressure is 1005 mb (29.68 inches).
HAZARDS AFFECTING LAND
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WIND: Tropical storm conditions are expected over portions of Maui County and the Big Island overnight and Wednesday. Tropical storm conditions are expected to begin over Oahu early Wednesday. Remember that wind gusts can be much stronger near higher terrain, and in the upper floors of high-rise buildings. Winds can also be especially gusty through gaps between mountains and where winds blow downslope.
RAINFALL: Showers will continue to increase over portions of the main Hawaiian Islands tonight and Wednesday. Olivia is expected to produce total rainfall accumulations of 5 to 10 inches in some areas, with isolated maximum amounts of 15 inches possible, especially in higher terrain. This rainfall may produce life-threatening flash flooding.
SURF: Large swells generated by Olivia will impact the main Hawaiian Islands over the next couple of days. This will result in dangerously high and potentially damaging surf, mainly along exposed east facing shores.
The intensity forecast operates under the assumption that the low level circulation center will be intact after emerging to the southwest of Maui and the Big Island. If this occurs, gradual weakening is expected to continue in line with all the guidance which shows moderate to strong shear continuing through the forecast period. Olivia is expected to become a remnant low within 72 hours, but there is a decent chance this will happen even sooner.
Key Messages:
1. As Olivia moves across the main Hawaiian Islands, it still bring worse impacts than recent Hurricane Lane to some areas. Those impacts could include flooding rainfall, damaging winds, and large and dangerous surf.
2. Significant impacts can occur well away from the center. In particular, the mountainous terrain of Hawaii can produce localized areas of strongly enhanced wind gusts and rainfall.
This is a Civil Defense Hurricane Olivia update for 7 p.m., Tuesday, September 11, 2018.
The Central Pacific Hurricane Center reports that as of 5 p.m., Tropical Storm Olivia is located 100 miles NE of Hilo, with sustained winds of 50 mph, moving W at 15 mph. The National Weather Service forecasts strong winds throughout the evening and overnight, especially for the northern half of Hawaii Island. Heavy rainfall and flash flooding is also possible.
Due to the Tropical Storm Warning for Hawaii Island, the following advisories are in effect:
For your additional information:
Civil Defense is monitoring the storm and will keep you informed of any changes that may affect your safety.
The Federal government is the only way to buy flood insurance. Visit https://www.floodsmart.gov for more info.
Actions to take whenever a tropical storm or hurricane nears Hawaii
All of Hawaii’s citizens should know what to do during a hurricane, tropical storm watches and warnings. Watches and warnings are prepared for the Hawaiian Islands by the National Weather Service Central Pacific Hurricane Center in Honolulu. When watches and warnings are issued, people should closely monitor the Internet, radio, TV, or NOAA Weather Radio for official bulletins of the storm’s progress and instructions from civil defense authorities. Jim Weyman, director of the Central Pacific Hurricane Center, said, “Although you and your family may have never experienced a hurricane, don’t be complacent! It’s not a matter of if a hurricane will occur, but when one will occur. All of the Hawaiian Islands are at risk for a hurricane and we should all know what actions to take.”
For the Central Pacific Ocean a Hurricane/Tropical Storm Watch means hurricane/tropical storm conditions are possible in the specified area of the Watch, usually within 48 hours.
When a Hurricane or Tropical Storm Watch is issued:
For the Central Pacific Ocean a Hurricane/Tropical Storm Warning means hurricane/tropical storm conditions are expected in the specified area of the Warning, usually within 36 hours.
When a Hurricane or Tropical Storm Warning is issued:
The Central Pacific Hurricane Center (CPHC) issues tropical cyclone warnings, watches, advisories, discussions, and statements for all tropical cyclones in the Central Pacific from 140 Degrees West Longitude to the International Dateline. The season officially begins on June 1 and ends on November 30. However, tropical cyclones can occur at any time. The National Weather Service Forecast Office in Honolulu activates the CPHC when: (1) a tropical cyclone moves into the Central Pacific from the Eastern Pacific, (2) a tropical cyclone forms in the Central Pacific, or (3) a tropical cyclone moves into the Central Pacific from the West.
For links to the latest weather forecasts, reports, radar, webcam and satellite imagery visit our Weather Page at hawaii247.com/weather
