838
FGMY70 PGUM 230844
ESFGUM
GUC010-MPC100-110-120-241000-

Hydrologic Outlook
National Weather Service Tiyan GU
644 PM ChST Sun Aug 23 2026


...HEAVY RAINFALL, FLOODING, AND MUDSLIDE POTENTIAL FOR THE MARIANAS
BEGINNING WEDNESDAY...

This Hydrologic Outlook is for Guam, Rota, Tinian, and Saipan.

A reinvigorated monsoon trough with a potential embedded tropical
disturbance will likely develop in the area and bring periods of
heavy rainfall to the Marianas starting midweek.

Between Wednesday and Friday, early ensemble guidance suggests 4 to 6
inches with a low probability of up to 10 inches for Guam and Rota,
and 3 to 5 inches with a low probability of up to 8 inches for Saipan
and Tinian.

Heavy showers will moisten soils throughout the event and increase
potential for mudslides.

Residents of the Marianas need to closely monitor this developing
situation as flood watches, advisories and flash flood warnings could
be issued later.

If living near streams and rivers, prepare to move items away from
stream and river banks. Make sure storm drains nearby are not
clogged, especially If living at low-lying areas.


$$

TM