Hawaii Severe Flood Watch | Effective 09/17/2026 20:40

Headline: 
Flood Watch issued September 17 at 5:40PM HST until September 18 at 6:00AM HST by NWS Honolulu HI
Event: 
Flood Watch
Urgency: 
Future
Effective: 
September 17, 2026 - 8:40pm
Expires: 
September 18, 2026 - 9:00am
Description: 
Remnant moisture from former Tropical Storm Norbert will bring periods of moderate to heavy showers to mainly windward sides of the Hawaiian Islands through late tonight. * WHAT...Flash flooding caused by excessive rainfall continues to be possible. * WHERE...Kauai, Niihau and Oahu. * WHEN...Through late tonight. * IMPACTS...Flood prone roads and other low lying areas may be closed due to elevated runoff and overflowing streams. Urban areas may receive more significant flooding and property damage due to rapid runoff. * ADDITIONAL DETAILS... - A band of remnant moisture from Norbert will move west across the islands through Friday, bringing moderate to locally heavy showers to mainly windward sides of the islands. There is a slight chance of thunderstorms as well, which could produce briefly higher rain rates, increasing the risk of flash flooding.
Instruction: 
You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.
Area Description: 
Niihau; Kauai Southwest; 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
Forcast Office: 
NWS Honolulu HI
Sender: 
w-nws.webmaster@noaa.gov