Heavy rainfall elevated streams across the island with efficient runoff due to high soil moisture content and locally intense rainfall rates.
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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.
Heavy rainfall elevated streams across the island with efficient runoff due to high soil moisture content and locally intense rainfall rates.
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 Feb 21, 10:03 AM HST, 3 hours 23 minutes earlier.
Area Forecast Discussion National Weather Service Honolulu HI 1003 AM HST Tue Feb 21 2023 .SYNOPSIS... The flooding threat will continue today and may linger into Wednesday for the western end of the state as deep tropical moisture pools northward over the region. Drier air and strong easterly trade winds are expected Wednesday into the second half of the week as low pressure to the west drifts away from the area. A wetter trade wind pattern is possible this weekend as an upper disturbance settles southward into the area. && .DISCUSSION... Several waves of heavy rain have moved over Kauai since yesterday afternoon resulting in widespread rainfall totals between 2 and 6". The Mount Waialeale gauge checks in with the highest total of 12.54" followed by 9.17" at N Wailua Ditch and 8.09" at Waiahi. Additional waves of heavy rain will develop within convergent southeasterly low- level flow and lift toward Kauai through the day. The flood watch remains in effect. The primary decision point for the afternoon package will be the potential for an extension through tonight. For Oahu, it appears low-level convergence has shifted west of the island and the flood threat for the remainder of the day will tend to diminish. At this time, anticipate allowing this portion of the watch to expire on schedule this evening. Amplification of the longwave pattern will continue into Wednesday as the existing upper low NW of Kauai refocuses southwest of the state and cuts off. Mid-level ridging will expand along 150W, its SEward expansion into the subtropics aided by a deepening trough along the US west coast. This will set the stage for the strong 1046mb high over the NE Pacific to migrate southward as the closed low near the islands begins to drift west. The gradual departure of larger scale forcing this afternoon through tonight combined with an increasing support for a strong push to trade winds suggests the organized flood threat could come to an end as early as this evening, though observations and latest trends will be reevaluated this afternoon. Backing mid-level flow will lag the development of trades at the surface. As such, even as breezy trade winds return to the islands during Wednesday, southeasterly mid-level flow will continue directing a portion of the tropical airmass toward Kauai. At this time, pockets of heavier showers are still likely over the western end of the state on Wednesday and potentially Wednesday night, but the tendency for organized bands of heavy rain will diminish as surface winds back to easterly. Previous Discussion. For the second half of the week, the east- southeast low-level flow will back to a more typical easterly trade wind direction. Wind speeds may reach the advisory level as strong high pressure (1040 mb) sets up north- northeast of the state. For the upcoming weekend, guidance shows an upper trough moving in from the northeast. Lowering upper heights and increasing instability associated with this upper feature could support increasing trade wind shower coverage. Although the bulk of the showers will favor windward areas, the brisk trades will manage to carry some into leeward areas, especially through the overnight and early morning periods this weekend. && .AVIATION... An upper low to the northwest of Kauai along with lingering deep tropical moisture has been supplying moderate to heavy showers across the Islands and a few isolated thunderstorms to Oahu and Kauai over night. These unsettled conditions are expected to continue today particularly for the western islands. An AIRMET Sierra for mountain obscuration for Kauai, Oahu, and the southeast areas of the Big Island will likely remain in place today due to the ongoing MVFR with isolated IFR conditions. Additionally, strengthening trades will increase the potential of low-level mechanical turbulence downwind of mountains, especially for the central smaller islands today. Therefore, AIRMET Tango for low-level moderate turbulence continues for Maui, Molokai, and Oahu. A period of potential light ice continues in a layer between 150/FL250, as a band of mid and upper level moisture lingers across the state. This should be mostly focused over the western islands. && .MARINE... A high pressure ridge building in from the northeast will produce strong to near-gale force trade winds across Hawaiian waters through the end of the week. Surface troughing and an upper low west of the state will tap into abundant tropical moisture, producing periods of showers, with isolated thunderstorms and embedded heavier showers across the region through Wednesday. A Small Craft Advisory remains in effect for most waters due to a combination of winds and rough seas through at least Friday. Surf along east facing shores will remain elevated and rough through the week due to persistent and strong trade winds over and upstream of the Hawaiian Islands. A High Surf Advisory (HSA) is in effect for east facing shores through at least Wednesday. East shore surf will likely hold at or near low end advisory levels through the weekend. A series of small, medium to long-period northwest (310-330) swells will move through the local waters through the weekend. Expect surf heights along north and west facing shores to remain well below the seasonal average through Sunday. South shore surf will also remain small through the weekend. A small, long-period south swell (170 degrees) could provide a small bump up in south shore surf for Sunday into early next week. && .HFO WATCHES/WARNINGS/ADVISORIES... Flood Watch until 6 PM HST this evening for Niihau-Kauai Leeward- Kauai Mountains-Waianae Coast-Oahu North Shore-Olomana-Central Oahu-Waianae Mountains-Kauai North-Kauai East-Kauai South-East Honolulu-Honolulu Metro-Ewa Plain-Koolau Windward-Koolau Leeward. High Surf Advisory until 8 PM HST Wednesday for Olomana-Maui Windward West-Kauai East-East Honolulu-Koolau Windward-Molokai Windward-Molokai Southeast-Windward Haleakala-Kipahulu-Big Island Southeast-Big Island East-Big Island North. Small Craft Advisory until 6 PM HST Friday for all Hawaiian waters except Maalaea Bay- && DISCUSSION...JVC AVIATION...Tsamous MARINE...TS
The South Kauai radar (PHKI), 36 km away, was scanning. The volume nearest the first event began at 23:27 UTC.
1 flash flood. Local standard time, as filed.
Kuhio Highway near the Hanalei Bridge was closed due to flooding.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Hawaii in 2023Every state in 2023This day in weather historyWarnings in Hawaii, February 2023
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: 1075386.