As Tropical Storm Olivia approached the islands from the east-northeast and then made a double landfall in Maui County on September 12th, it brought gusty winds and heavy precipitation. Most of its effects were concentrated over Maui, Molokai, and Oahu.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS HFO wrote it up.
As Tropical Storm Olivia approached the islands from the east-northeast and then made a double landfall in Maui County on September 12th, it brought gusty winds and heavy precipitation. Most of its effects were concentrated over Maui, Molokai, and Oahu. The system downed trees, caused power outages and debris flows, and generated flash flooding. The costs of damages had not yet been assessed. There were no reports of serious injuries.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Honolulu, HI wrote its last area forecast discussion before the first event at Sep 11, 10:11 AM HST, 5 hours 36 minutes earlier.
Area Forecast Discussion National Weather Service Honolulu HI 1011 AM HST Tue Sep 11 2018 .SYNOPSIS... Tropical Storm Olivia is forecast to move west across the main Hawaiian Islands tonight through tomorrow. The atmosphere over the islands will remain very moist through Saturday evening. A low aloft far northeast of the islands will move southeast, passing northwest of Kauai on Thursday. Instability from this low combined with moisture from Olivia will keep the weather wet through Saturday evening. A surface high will build far northeast of the state early next week and drier air will spread west over the islands. && .DISCUSSION... As of 930 AM, Tropical Storm was about 230 miles west northwest of Maui, moving west at 12 mph. Olivia is forecast to move across the main Hawaiian Islands tonight through tomorrow. Winds will shift out of the north and strengthen as the center of the storm approaches. Cloud bands on the periphery of the storm have been bringing scattered showers to windward areas this morning. Heavy rains will spread over the islands tonight. When Olivia passes southwest of the islands tomorrow, moisture from the storm will linger over the area. The atmosphere will remain very moist as a low aloft approaches from the northeast. The low aloft will make the atmosphere unstable, so the threat of heavy rain will persist after the winds from Olivia have subsided. A Flood Watch remains in effect for all islands through Thursday night. The atmosphere will gradually dry out and stabilize as the moisture from Olivia and the low aloft move away to the west. A surface high will build far northeast of the area early next week and drier weather will spread west over the islands. Please see the Hurricane Local Statement (HLSHFO) and Local Watch/Warning Statement (TCVHFO) on our website for detailed weather information about Olivia and expected impacts to your local area. The Central Pacific Hurricane Center also posts the latest Olivia Forecast Advisory tracks at weather.gov/cphc && .AVIATION... Tropical Storm Olivia continues to approach the state from the east. Outer rain bands are already moving onshore over some windward areas. AIRMET SIERRA is in effect for mountain obscuration for windward and mountain areas of Molokai and Maui. This will likely be extended to other areas during the day today or tonight. As Olivia approaches, northeasterly winds are forecast to gradually strengthen later today and tonight. An AIRMET for low level turbulence will likely be issued at that time. SIGMET NOVEMBER is currently posted for Tropical Storm Olivia. && .MARINE... As Tropical Storm Olivia approaches the state from the east, winds will begin to increase today. For the latest on Olivia, please see the advisories from the Central Pacific Hurricane Center. Swell from Olivia will spread west today. A High Surf Warning (HSW) is in effect for east facing shores of the Big Island and Maui County, while a High Surf Advisory (HSA) remains in effect for east facing shores of Oahu. Surf will begin to rapidly increase this evening and is expected to reach warning levels along east facing shores of the Big Island and Maui County tonight into Wednesday. Lower surf is expected for east facing shores of Oahu at this time, but the HSA may be upgraded to an HSW there later if conditions warrant. A small SW swell from the Tasman Sea will bring inconsistent, small surf to south facing shores today. The morning coastal waters forecast will be delayed as we incorporate the latest forecast package information for Olivia. && .HFO WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch from this evening through late Thursday night for all Hawaii islands. High Surf Advisory until 6 PM HST Wednesday for Oahu South Shore- Oahu Koolau-Olomana. Tropical Storm Warning for Oahu-Molokai-Lanai-Kahoolawe-Maui-Big Island. Tropical Storm Watch for Niihau-Kauai. High Surf Warning until 6 PM HST Wednesday for Molokai Windward- Maui Windward West-Windward Haleakala-South Big Island-Big Island North and East. Tropical Storm Warning for Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui County Windward Waters-Maui County Leeward Waters-Maalaea Bay-Pailolo Channel-Alenuihaha Channel- Big Island Windward Waters-Big Island Leeward Waters-Big Island Southeast Waters. Tropical Storm Watch for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel. && DISCUSSION...Bohlin AVIATION...Houston MARINE...Kinel
The Kamuela/Kohala Apt radar (PHKM), 93 km away, was scanning. The volume nearest the first event began at 10:55 UTC.
11 heavy rain, 8 strong wind, 4 flash flood, 1 debris flow. Local standard time, as filed.
Tree downed on Oahu over one lane of Likelike Highway near the tunnel, Kaneohe-bound.
Hana Highway closed in both directions one mile west of Keanae on Maui due to a debris flow from heavy rain.
Trees downed blocking Hana Highway on Maui at mile markers 21 and 26.
Deep water on Ulaino Road near Hana on Maui forced its closure. Waikoloa Road near Hana was also closed because of water on the roadway. Later in the day after 1400 HST, Honokohau Stream overflowed onto the bridge in Honokohau in West Maui and closed Honoapiilani Highway in that area.
Tree downed at Pali Lookout on Oahu.
Tree downed at Diamond Head Road and Makalei Place on Oahu's south shore.
Another tree downed along Likelike Highway on Oahu near the tunnel in the Kaneohe-bound lane.
Deep water closed the roadway (Highway 450) near Kawela on the island of Molokai.
Downed trees reported on Maui at the intersection of Kawai Ola Place and Hana Highway near Hana, and two mile southeast of Nahiku along Hana Highway.
Ironwood tree felled by strong winds was blocking Kamehameha Highway near Sunset Elementary School.
Gusty winds caused a hanging limb from a tree on Lanikuhana Drive between Kamehameha Highway and Anania Drive in Mililani on Oahu.
Kalihi Stream overflowed onto Dillingham Boulevard in Honolulu on Oahu, closing the roadway.
Heavy rain closed a potion of Kalanianaole Highway on Oahu near the Makapuu lighthouse in the Hawaii Kai-bound direction.
Waikane Stream overflowed after heavy rain and closed Kamehameha Highway on Oahu between Waikane Valley Road and Waiahole Valley Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Hawaii in 2018Every state in 2018This day in weather historyWarnings in Hawaii, September 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 778668, 778672, 778674, 778681, 778676, 778678, 778679, 778680, 778691, 778700, 778692, 778699, 778693, 778703, 778704, 778682, 778705, 778706, 778707, 778708, 778709, 778698, 778683, 778714.