Flood Watch

NWS Honolulu HI · US

Updated

This event was updated at 2026-09-18 12:59:00 UTC.

Details

Flood Watch Remains In Effect Through Late Tonight

Event: Flood Watch
Issued: 2026-09-18 03:40:00 UTC
Onset: 2026-09-18 03:40:00 UTC
Message expires: 2026-09-18 16:00:00 UTC
Expected end: 2026-09-18 16:00:00 UTC
Category: Meteorological
Urgency: Future
Severity: Severe
Certainty: Possible
Response: Prepare

Description

Overview

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.

Instructions

You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.

Affected areas

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

Public contact

Issuer: NWS Honolulu HI
Website: http://www.weather.gov

Message record

Received: 2026-09-18 03:40:40 UTC
Issue to receipt: ~41s
CAP status: Actual
CAP message type: Update
Lifecycle: Updated
Source: NWWS-OI
Feed: NWWS
Recovered: No

CAP routing and identity

ULID: 01M2S9M8AQ3X0Y7EDM5Z9HM6R8
Identifier: urn:oid:2.49.0.1.840.0.e430d9b6ba91319e4d463fc108a9c7181b66e0bf.002.1
Sender: w-nws.webmaster@noaa.gov
Scope: Public
CAP source: 211803 v2.3.0
Handling codes: IPAWSv1.0
Issuing office: NWS Honolulu HI
AWIPS ID: CAPHFO
NWWS sequence: nwws_processor.5048
WMO heading: XOHW50
WMO data type: CAP alert message XML (XO)
WMO geography: Hawaiian Islands (HW)
WMO bulletin number: 50

References

Identifier: urn:oid:2.49.0.1.840.0.cd5e07b644c2fb83e2ef2cf2067d094ddb255fbf.001.1
Sender: w-nws.webmaster@noaa.gov
Sent: 2026-09-17 13:15:00 UTC

Identifier: urn:oid:2.49.0.1.840.0.0e2b6a9e0b5751903ff2e2982181acae7f3226f0.001.1
Sender: w-nws.webmaster@noaa.gov
Sent: 2026-09-17 02:03:00 UTC

Identifier: urn:oid:2.49.0.1.840.0.7b0791a98da5b2051b44577526918dda9d06e0cb.001.1
Sender: w-nws.webmaster@noaa.gov
Sent: 2026-09-17 01:41:00 UTC

Event codes

Name	Value
SAME	FFA
NationalWeatherService	FAA

Parameters

Name	Value
AWIPSidentifier	FFAHFO
WMOidentifier	WGHW60 PHFO 180340
NWSheadline	FLOOD WATCH REMAINS IN EFFECT THROUGH LATE TONIGHT
BLOCKCHANNEL	EAS
BLOCKCHANNEL	NWEM
EAS-ORG	WXR
VTEC	/O.CON.PHFO.FA.A.0012.000000T0000Z-260918T1600Z/
eventEndingTime	2026-09-18T06:00:00-10:00
BLOCKCHANNEL	CMAS
expiredReferences	w-nws.webmaster@noaa.gov,urn:oid:2.49.0.1.840.0.0e2b6a9e0b5751903ff2e2982181acae7f3226f0.001.1,2026-09-16T16:03:00-10:00 w-nws.webmaster@noaa.gov,urn:oid:2.49.0.1.840.0.7b0791a98da5b2051b44577526918dda9d06e0cb.001.1,2026-09-16T15:41:00-10:00

Locations

Location data

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

Name	Value
SAME	015007
SAME	015003
UGC	HIZ001
UGC	HIZ003
UGC	HIZ004
UGC	HIZ006
UGC	HIZ007
UGC	HIZ009
UGC	HIZ010
UGC	HIZ011
UGC	HIZ029
UGC	HIZ030
UGC	HIZ031
UGC	HIZ032
UGC	HIZ033
UGC	HIZ034
UGC	HIZ035
UGC	HIZ036