An upper level trough and a surface low pressure system to the west caused localized flooding on Oahu.
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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 upper level trough and a surface low pressure system to the west caused localized flooding on Oahu.
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 Mar 17, 3:06 AM HST, 1 hour 54 minutes earlier.
Area Forecast Discussion National Weather Service Honolulu HI 306 AM HST Mon Mar 17 2025 .SYNOPSIS... The potential for locally heavy showers and a few thunderstorms will persist today, especially over the western end of the state, as an upper-level disturbance produces unstable conditions. Light to moderate east-southeast winds will focus rainfall across windward and mauka locations, while daytime sea breezes trigger showers over interior and leeward areas. A return to moderate to breezy easterly trade winds is expected later tonight through Tuesday, with showers primarily favoring windward areas through the rest of the week. Trade winds may become disrupted once again next weekend as a front approaches the region. && .DISCUSSION... Short-term model guidance remains in good agreement, indicating that the unstable pattern will persist today as a deep area of low pressure lingers to the west of the state. Pulses of energy rotating around this upper low will lead to periods of heavy showers and thunderstorms, especially over the western end of the state. Convergent southeast flow interacting with the island terrain will maintain a high potential for localized heavy showers and storms, which could develop and anchor periodically. This scenario quickly evolved over the windward side of Oahu overnight, where 3 to 5 inches of rain were observed within a six- hour period, driving water levels in the streams to flood stage. Given the sensitivity and saturated grounds, along with the potential for additional heavy showers, a Flood Watch has been issued for Niihau, Kauai and Oahu through this afternoon. The moist and unstable east-southeast flow could persist into tonight, but chances for widespread heavy rainfall will slowly diminish. The upper-level trough stretching over the region will begin to slowly weaken, allowing the mid-levels to warm slightly, and the zone of low-level convergence will lift farther north. Expect continued windward rainfall with trades gradually filling in from east to west. By midweek, a return to moderate to breezy trade winds is expected as high pressure builds to the north and the surface low west of the state moves farther away. Meanwhile, the upper low will weaken into an open trough as it drifts eastward over the region from Tuesday through Thursday. This pattern will shift showers back to the typical windward and mauka locations statewide, especially as pockets of low-level moisture move through. More stable conditions are anticipated later in the week as upper heights rise and the weakening upper trough exits east of the state. The long-term guidance is now in slightly better agreement for next weekend compared to 24 hrs ago, and shows the trades easing once again with a cold front approaching the region. && .AVIATION... Light to moderate ESE winds as a surface low and trough move closer to the islands. There is some instability, so expect SHRA and a few TSRA. IFR/MVFR conds can be expected SHRA/TSRA. Elsewhere, VFR conds should prevail. AIRMET Sierra is in effect for mtn obsc for all of Oahu and windward portions of the rest of the islands. && .MARINE... An area of low pressure just northwest of the state is generating light to moderate east-southeast winds over the western half of the state and moderate to locally fresh east southeast winds over the eastern half. Isolated thunderstorms are possible through today, mainly for the western waters, due to the proximity of the low. As the low weakens and drifts westward today and Tuesday, a couple of strong high pressure systems will pass north of the state. Winds will gradually back to a more typical easterly direction and increase to moderate to locally fresh speeds statewide by Tuesday night, before becoming locally strong during the second half of the week when Small Craft Advisories are likely for the winds and rough seas. A small, medium-period north-northwest swell (340-350 degree) will peak today before fading into Tuesday, providing a boost in surf for north and some exposed west facing shores. In the long range, a series of small to moderate, long-period northwest (310-330 degree) swells look to keep surf from going flat for north and west facing shores Tuesday through much of next week. The next significant northwest swell may arrive next weekend. Expect choppy surf along east facing shores through the first half of the week. East shore surf may pick up a notch or two by midweek as wind speeds increase locally and upstream. A small boost in south shore surf is possible Tuesday through the rest of the week as series of small, long-period south swells move through. && .HFO WATCHES/WARNINGS/ADVISORIES... Flood Watch in effect for Niihau, Kauai and Oahu through 6 PM HST today. && DISCUSSION...Gibbs AVIATION...Walsh MARINE...Almanza
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Three vehicles were stranded in knee deep water near Waikane Valley Rd. Additionally, Kamehameha Hwy was closed in both directions near Waikane Valley Bridge.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Hawaii in 2025Every state in 2025This day in weather historyWarnings in Hawaii, March 2025
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: 1239772.