Hydrologic Outlook
ASZ001>004-160100-

Hydrologic Outlook
National Weather Service Pago Pago  AS
148 AM SST Mon Dec 15 2025

...Elevated Flood and Landslide Risk with Prolonged Rainfall
today through at least Thursday...

A prolonged period of widespread showers and possible
thunderstorms is forecast to impact the Samoa region beginning
today and continuing through at least Thursday. A large and
strong trough is positioned to the west of the territory, with the
potential to develop embedded areas of lower pressure.

The potential for flash flooding may extend beyond Thurdsay
depending on the exact positioning of the trough at this time.
The extended duration of rainfall raises the potential for
widespread flash flooding and landslides, as grounds are likely
to become saturated.

Visit weather.gov/ppg for the latest weather updates.

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Hydrologic Outlook
MTC029-053-089-161900-

Hydrologic Outlook
National Weather Service Missoula MT
1216 PM MST Sun Dec 14 2025

...AN ATMOSPHERIC RIVER PRODUCING MODERATE TO HEAVY PRECIPITATION
WILL INCREASE THE RISK FOR ROCK AND LANDSLIDES, ALONG WITH RISING
CREEKS AND RIVERS...

NORTHWEST MONTANA

A prolonged Atmospheric River is expected to impact Western Montana
and North-Central Idaho from Monday through Wednesday, bringing
moderate to heavy precipitation. Snow levels are anticipated to
start around 7,000 feet on Monday before falling to valley floors
behind a cold front early Wednesday. The most likely rainfall
scenario forecasts 0.75 to 1.25 inches for the valleys of Lincoln,
Mineral, Sanders and Flathead Counties in northwest Montana.  1.50
to 3 inches expected in the mountains.  A high-end scenario could
bring a total of 4 inches to the Cabinet and Purcell Mountains.

Due to already saturated ground, rainfall will increase the risk of
rock and landslides across northwest Montana. Continue to monitor
the latest forecast updates as this system approaches.
$$