An extended period of enhanced rainfall with embedded locally heavy rainfall rates overwhelmed a few local roads on Pearl City Peninsula.
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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.
An extended period of enhanced rainfall with embedded locally heavy rainfall rates overwhelmed a few local roads on Pearl City Peninsula.
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 20, 3:51 PM HST, 1 hour 39 minutes earlier.
Area Forecast Discussion National Weather Service Honolulu HI 351 PM HST Mon Feb 20 2023 .SYNOPSIS... Wet conditions will persist for much of the state during the next couple of days under a continued moist east to southeast wind flow, and chances for flooding rainfall will increase across the western end of the island chain through tonight as a deep low settles several hundred miles west of Kauai. The low will weaken and drift away from the state late Wednesday and Thursday, decreasing the flood threat and allowing a breezy trade wind flow to develop from east to west. Somewhat wet and breezy trade winds will prevail late in the work week and into the weekend. && .DISCUSSION... Wet conditions prevail across portions of most islands as deep moisture lingers within a moderately unstable atmosphere. The upper low that was aiding the recent heavy rainfall is weakening well south of the state, but another, deeper low centered about 750 miles northwest of Kauai is digging southward and helping to maintain some instability over Hawaii. Breezy trade winds generated by strong high pressure far to the northeast of the state gradually veer southeasterly across the island chain, as they are drawn into the low northwest of Kauai. Under this moist, convergent, east to southeast flow, persistent moderate showers have been falling across the Kau, Puna, and North and South Hilo Districts of the Big Island and the Kipahulu area on east Maui, where 0.5 to nearly 2 inches of rain has fallen during the past six hours. Sporadic rainfall moderate to locally heavy showers have been flaring across Oahu and Kauai this afternoon, dropping around an inch of rain in places. Latest radar trends point toward increased showers around Kauai and Oahu, and satellite data show cooling cloud tops across the western half of the state as instability increases. Chances for heavy rainfall and thunderstorms will increase through tonight across the western end of the state. As the low northwest of Kauai drops southward, slightly closer to the islands, upper level forcing will increase, mainly over and west of Kauai, but across Oahu as well. This will likely combine with the convergent southeasterly low level flow to produce an increase in heavy showers and thunderstorms. Given recent trends, the Flood Watch that is in place for Kauai County was expanded to Oahu through Tuesday afternoon. We cannot rule out a few heavy showers and thunderstorms elsewhere, mainly windward, but the chance for flooding diminishes east of Oahu and will be left out of the Flood Watch, for now. Thus, Maui COunty and the Big Island, expect continued windward shower activity with brief leeward flare ups of heavier rain along with thickening high clouds. A Winter Weather Advisory remains in effect for the high summits of the Big Island as deeper moisture reaches higher elevations and produces periods of freezing rain showers. Only subtle changes in the overall pattern are due on Tuesday. The Flood Watch is set to continue for Kauai County and Oahu, as a convergent band of heavy showers sets up near or just south and west of those islands. The Flood Watch may need to be extended into early Wednesday, depending on how the heavy rainfall develops. In addition, the latest GFS and ECMWF runs show some increase in difluence aloft near or just southwest of the eastern end of the island chain Tuesday night, which suggests that an expansion of the Flood Watch to additional islands is possible, though unlikely. The frequency of rainfall will gradually diminish late Wednesday and Thursday as the upper low and surface trough west of the state slowly weaken and begin to drift westward. This will allow low to mid level ridging to bring in drier air from the east, along with an increase in breezy easterly trade winds. A narrow upper level trough moving in from the northeast will maintain instability, and fast-moving, moderate to briefly heavy showers will move through. However, since available moisture will decrease and showers will moving quickly, flooding is not expected. The breezy and potentially windy and wet trade wind weather should persist through next weekend. && .AVIATION... Abundant low level moisture along with an unstable atmosphere will maintain heavy rain chances with isolated thunderstorms possible for all islands through tonight. Several thunderstorms have been observed near a few TAF sites today. Moderate to heavy showers with MVFR and embedded IFR conditions are expected to continue impacting the islands. An AIRMET Sierra for mountain obscuration on all islands will likely remain in place through tonight. In addition, some of the mid and upper- level clouds may produce periods of light icing in the layer from 15 to 25 kft through tonight. A building high pressure system north of the state will cause trade winds to continue to increase today and tomorrow to locally breezy levels. An AIRMET Tango for low-level tempo moderate turbulence is in effect over and downwind of the higher terrain for Maui, Molokai, and Oahu. && .MARINE... High pressure northeast of the state and troughing to the northwest will support a continuation of strong to near-gale force east- southeast winds across the waters through the middle of the week. The troughing will shift westward Thursday through next weekend, which will back the winds to a more typical east and eventually east-northeast trade wind direction. A Small Craft Advisory remains in effect for most waters due to a combination of winds and seas through at least Friday. Surf along east facing shores will remain rough through the week due to persistent and strong east to southeast winds. Surf will likely return to the 10-foot advisory level sometime Tuesday due to increasing easterly trade winds over and upstream of the islands. East shore surf will likely hold at or near advisory levels through the weekend. A small, long-period northwest (310-320 degrees) swell will linger through the first half of the week before easing Thursday. Expect surf to remain well below the seasonal average through the week. A new, small northwest swell could give north shore surf a small boost next weekend. South shore surf will remain minimal into 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 through Tuesday afternoon for Oahu, Kauai, and Niihau. Winter Weather Advisory until 6 PM HST Tuesday for Big Island Summits. Small Craft Advisory until 6 PM HST Friday for all Hawaiian waters except Maalaea Bay. && DISCUSSION...Wroe AVIATION...Tsamous MARINE...TS
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HONOLULU HI
446 PM HST MON FEB 20 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0100 PM FLASH FLOOD 1 SE PAHALA 19.20N 155.48W
02/20/2023 HAWAII HI EMERGENCY MNGR
ROAD CLOSURES DUE TO FLOODING AT APPROX.
1PM, MAMALAHOA HWY (RTE 11) IN THE AREA OF
KAWA FLATS IN KAU (MILE MARKERS 56-62), WOOD
VALLEY RD NORTH OF PAHALA, AND KAALAIKIK RD.
&&The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Officials reported that the Pearl City Peninsula Compound main gate and Victor Wharf Access Road were 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: 1075415.