Six hours later, Olivia began another weakening trend that resulted in the hurricane being downgraded to Category 1 status on September 8, east of the 140th meridian west.

United States President Donald Trump issued a disaster declaration for Hawaii to aid with emergency response efforts.

Associated thunderstorm activity increased over the next few days, and by early August 31, a broad low-pressure area had developed several hundred miles south of Mexico's southwestern coast.

[1] While the depression was located over warm sea surface temperatures, northeasterly wind shear prevented any intensification from occurring on September 1.

This led to the depression strengthening into Tropical Storm Olivia by 00:00 UTC on September 2, while it was located 520 mi (840 km) south of Cabo San Lucas, Mexico.

[9] Olivia became a Category 1 hurricane around 00:00 UTC on September 4, while located 575 mi (925 km) southwest of Cabo San Lucas.

The cyclone continued to intensify, reaching its initial peak intensity as a Category 3 major hurricane at 00:00 UTC on September 5, with maximum sustained winds of 125 mph (205 km/h).

[10] The hurricane began to weaken shortly after its initial peak as sea surface temperatures decreased, wind shear increased, and dry air incorporated into the storm.

Models had predicted that Olivia would weaken as a result of dry air and lower sea surface temperatures, however, a second, unexpected round of intensification occurred.

The cyclone peaked around 00:00 UTC on September 7, as a Category 4 hurricane with 1-minute maximum sustained winds of 130 mph (215 km/h) and a minimum central pressure of 951 mbar (28.08 inHg), while located over 1,265 mi (2,036 km) west of Cabo San Lucas.

[13] Cooler sea surface temperatures of 77–79 °F (25–26 °C) and low-to-mid-level dry air caused Olivia to weaken shortly after its peak.

[1] Continuing to track west-northwestward under the subtropical ridge,[14] Olivia gradually weakened as it approached the Central Pacific Ocean, with cloud tops warming and its eye temperature decreasing.

[17] After having fallen to Category 1 status, the cyclone crossed the 140th meridian west and entered the Central Pacific Basin around 00:00 UTC on September 9.

The hurricane strengthened to 85 mph (140 km/h) by 00:00 UTC on September 10 and maintained that intensity for 12 hours before increasing wind shear caused the storm to weaken once more.

[1] Flow from low-level trade winds had turned Olivia to the west-southwest and caused it to slow down by 00:00 UTC on that day.

High wind shear and interaction with the mountainous terrain of the Hawaiian Islands led to the rapid depletion and displacement of convection away from Olivia's center.

A tropical storm watch was issued for the islands of Hawaii, Maui, Molokai, Lanai, Kahoolawe, and Oahu on September 10 at 03:00 UTC.

[1] The United States Coast Guard initiated Condition Whiskey[nb 2] at 08:00 HST on September 8 for ports in Hawaii, Maui, and Honolulu counties, expecting gale-force winds to occur within 72 hours.

By 08:00 HST on September 9, ports in Hawaii and Maui counties were upgraded to Condition Yankee, with the expectation of gale-force winds within 24 hours.

[26] Ports in Hawaii, Maui, and Honolulu counties were upgraded to Condition Zulu at 08:00 HST on September 11, when gale-force winds were expected to occur in less than 12 hours.

The Federal Emergency Management Agency (FEMA) readied personnel and supplies on Maui, and the Hawaii National Guard stationed troops and transportation trucks on the eastern side of the island.

[31] Olivia brought heavy rainfall, winds, and high surf to the main Hawaiian Islands, less than a month after Hurricane Lane dropped a record 58 in (1,500 mm) of rain on the state.

[32][33] From September 11–12, 8–20 ft (2.4–6.1 m) high surf was reported along the northern and eastern facing shores of the Big Island, Maui, Molokai, and Lanai.

[42] Multiple parks and forest reserves were closed to visitors due to a combination of water damage, land erosion, and downed trees.

Hololani Resort Condominiums and Goodfellow Bros, the company performing the work, was fined $75,000 in that month for violating state health and county environmental regulations.

[41] Torrential rainfall and flooding from Hurricanes Lane and Olivia reduced water flow and damaged a control gate in the Honokohau Stream ditch system.

[58][59][60][61] A pipe overflowed from excessive rainfall, sending over 32,000 US gal (120,000 L) of raw sewage into the Kapalama Stream and Honolulu Harbor; the city disinfected the waters.

[57] A 100 ft (30 m) landslide occurred at the top of the Manoa Falls Trail around a week after the storm, taking down trees and boulders.

[55] Hotel occupancy dropped an average of 2.1% in September for Maui compared to the same time in 2017 as a result of hurricanes Lane and Olivia.