Severe · Flood WatchActive alert
Flood Watch issued September 21 at 3:35PM ChST until September 23 at
Affecting Guam
In effect until: Sep 21, 2026, 8:15 PM
Guam
Possible impact zone; conditions develop through 8:15 PM.
You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.
Read the original bulletin (official text)
* WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...Guam. * WHEN...From Tuesday morning through Wednesday evening. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. Low-water crossings may be flooded. * ADDITIONAL DETAILS... - Heavy rainfall from Invest 91W located south of Guam may lead to flash flooding Tuesday through Wednesday evening. Guidance shows 2 to 5 inches of rain falling during the watch period as Invest 91W moves just west of Guam. Many locations across Guam have already seen 2 to 4 inches of rain since Saturday and soils remain wet from heavy rainfall the last couple of weeks. This will allow for a lower threshold for flash flooding over the next couple of days. - http://www.weather.gov/safety/flood
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Alert data: U.S. National Weather Service / NOAA · Translation: WeatherTranslate™