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FGMY70 PGUM 230729
ESFGUM
GUC010-MPC100-110-120-241000-

Hydrologic Outlook
National Weather Service Tiyan GU
529 PM ChST Mon Jun 23 2025


...HEAVY RAINFALL LIKELY LATE IN THE WEEK THROUGH THE WEEKEND...

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

A tropical disturbance could bring heavy rain to the Marianas from
Thursday evening through Sunday. Latest model guidance shows a
surface trough within Chuuk State that is expected to move northwest
over the next couple of days. This trough is expected to develop
into a weak circulation Thursday or Friday near the Marianas. Models
differ on location and strength of this circulation, however, they
do agree that heavy rainfall is likely as early as Thursday, but
most likely Friday through the weekend.

There is a potential for Guam and the CNMI to see rainfall amounts
varying from 5 to 10 inches by Sunday, though locally heavier
amounts are possible. This rainfall is expected to produce minor
flooding across the islands, with flash flooding possible in the
areas of heavier rainfall.

Residents in the Marianas need to closely monitor this developing
situation as watches, advisories and 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.

$$

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