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Areal Flood Watch — Guam, GU
Issued
7:00 p. m. CDT · lun., sept. 21 2026
Expires
7:00 a. m. CDT · mié., sept. 23 2026
Issuing Office
NWS PGUM

Affected Areas

Guam, GU

Official Bulletin

924
WGMY60 PGUM 210535
FFAGUM

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Tiyan GU
335 PM ChST Mon Sep 21 2026

GUZ001-212015-
/O.NEW.PGUM.FA.A.0005.260922T0000Z-260923T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Guam-335 PM ChST Mon Sep 21 2026

...FLOOD WATCH IN EFFECT FROM TUESDAY MORNING THROUGH WEDNESDAY
EVENING...

* 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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

Williams