Flood Watch Issued for Kauai, Niihau and Oahu as Heavy Rain Moves In Through Thursday
The National Weather Service says deep tropical moisture could bring flash flooding to Kauai, Niihau and Oahu from Wednesday night through Thursday afternoon.
A flood watch is in effect for Kauai County and Oahu, including Niihau, because of a threat of heavy rain. The National Weather Service (NWS) issued it early Wednesday, Oct. 7, 2026.
Forecasters asked residents and visitors to keep checking updated forecasts.
What we know
According to the NWS, a developing area of low pressure north of the islands will pull deep tropical moisture northward. Hawaii News Now adds that a cold front approaching from the northwest will shift winds to the southeast.
Heavy showers and isolated thunderstorms are expected to develop Wednesday night and continue through Thursday. Forecasters said heavy showers could "train," meaning they repeatedly pass over the same areas and produce intense rain rates.
The NWS said flood-prone roads and other low-lying areas may close because of elevated runoff and overflowing streams. It added that urban areas could see more significant flooding and property damage because of rapid runoff.
Could Maui County be added?
Maui County is not currently under the watch. An NWS forecast discussion quoted by Maui Now said later shifts would evaluate a possible expansion to Maui County, pending more data. The sources don't say whether that will happen.
The rest of the week
Hawaii News Now says scattered showers are expected to linger through Saturday. Drier conditions and returning trade winds are due Sunday.
The outlet also noted ocean conditions. A near-advisory-level south swell begins to fade Wednesday, and a similar south swell is due over the weekend. A moderate northwest swell peaks Wednesday, with another near-advisory-level northwest swell due early next week.
What it means for you
If you live in or are visiting Kauai, Niihau or Oahu, expect possible road closures and standing water, especially in low-lying and flood-prone spots, from Wednesday night into Thursday. Plan Thursday commutes and outdoor activities with that in mind.
The NWS asked people to be ready to act if a flash flood warning is issued. Check the latest forecasts through Thursday afternoon, when the watch is currently set to end.
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Quick answers
How long does the flood watch last?
It runs from Wednesday evening through Thursday afternoon.
Which islands are under the flood watch?
Kauai, Niihau and Oahu are covered. Maui County isn't included for now, though forecasters said they would evaluate an expansion.
What should people do?
Based on the NWS guidance in the sources, flash flooding is possible. Residents should monitor forecasts and be prepared to act if flash flood warnings are issued.
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