Olivia downgraded to a tropical storm as it approaches Hawaii

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(KHON) – Air Force Reserve Hurricane Hunters recently found that Olivia has become a tropical storm with maximum sustained winds near 70 mph with higher gusts. Gradual weakening is expected as Olivia continues to approach the main Hawaiian Islands.

Olivia is moving toward the west near 9 mph. A continued west to west-southwest motion is expected for the next few days.

On the forecast track, the center of Olivia will be moving over the main Hawaiian Islands Tuesday night into Wednesday.

Hurricane-force winds extend outward up to 15 miles from the center and tropical-storm-force winds extend outward up to 105 miles.

Watches and Warnings

A tropical storm warning is in effect for Maui County including the islands of Maui, Molokai, Lanai, and Kahoolawe, and Hawaii County.

A tropical storm watch is in effect for Oahu.

A tropical storm warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours.

A tropical storm watch means that tropical storm conditions are possible in the watch area within 48 hours.

Interests on Kauai and Niihau should closely monitor the progress of Olivia.

Keep in mind, changes will occur in forecast track and intensity as the storm gets closer. Download our KHON2 News mobile app and turn on the push alert notifications to get the very latest.

Location: 21.9N 149.1W

  • ABOUT 415 MI…670 KM ENE OF HILO HAWAII
  • ABOUT 565 MI…910 KM E OF HONOLULU HAWAII

Maximum Sustained Winds: 70 MPH…115 KM/H
Present Movement: W OR 270 DEGREES AT 9 MPH…15 KM/H

Hazards affecting land

WIND: Tropical storm conditions are expected somewhere within the warning area starting late Tuesday. Tropical storm conditions are possible within the watch area starting late Tuesday night or early Wednesday morning.

RAINFALL: Olivia is expected to produce total rainfall accumulations of 10 to 15 inches. Isolated maximum amounts of 20 inches are possible, especially over windward sections of Maui County and the Big Island. This rainfall may produce life-threatening flash flooding.

SURF: Large swells generated by Olivia will spread from east to west across the Hawaiian Islands early this week. This will cause surf to build along exposed east facing shorelines as Olivia approaches. This surf may become damaging across parts of the state.

Olivia still has a very well defined low level circulation center, albeit with a somewhat asymmetric wind field. Air Force Reserve Hurricane Hunters confirmed what the 1623 UTC SSMIS and 1849 UTC GMI passes showed, that the system lacks a well-organized convective core. Recent visible satellite images are showing new convective bands developing on the east side of the circulation center, however. The initial intensity was lowered to 65 kt based on the reconnaissance data. 

The initial motion is estimated to be 270/8. There is no change to the forecast track philosophy for this package, as Olivia is steered toward the west by a deep layer ridge to the west through north of the cyclone. This will continue to impart a just south of due west motion for the next 72 hours. The consensus models remain tightly clustered and have not budged. Our track forecast continues to reflect a blend of the consensus models and the ECMWF. It is worth noting that the last four runs of the GFS have trended north, and is now coming into much better agreement with the guidance consensus as well. After 72 hours, an upper level low will approach Olivia from the north and begin to pull the tropical cyclone on a more west-northwestward motion. Even at 120 hours, the guidance is fairly tightly clustered, and our track forecast remains very close to TVCN, HMON, HWRF, and FSSE.

Olivia remains over marginal sea surface temperatures of about 26.5C, but is approaching the edge of a weak shear environment, according the UW-CIMSS analysis. The SSTs will be warming along the forecast track, but the shear will begin gradually increasing soon. Without a strong eyewall or core, weakening should begin fairly soon after the shear increases. Our forecast is on the higher end of the guidance envelope through the first few days, but it is possible that weakening could occur faster due to shear effects and interaction of the circulation with island terrain.

It is important to not focus on the exact forecast track and intensity when planning for Olivia. Persons on the main Hawaiian Islands east of Kauai should finish their preparations for direct impacts from this system starting as early as Tuesday night. Those impacts could include intense flooding rainfall, damaging winds, and large and dangerous surf.

Regardless of the exact track and intensity that Olivia takes as it approaches the islands, significant effects often extend far from the center. In particular, the mountainous terrain of Hawaii can produce localized areas of strongly enhanced wind gusts and rainfall, even well away from the tropical cyclone center.

Copyright 2019 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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