956
AGUS74 KWCO 092012
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
200 PM CST TUE DEC 9 2025

...Considerable flooding is ongoing, with landslides possible across
portions of the Pacific Northwest this week... Rain and snowmelt is
expected to generate urban, small stream, and isolated minor river flooding
across portions of the Northern Rockies this week... Flash flooding
possible in American Samoa...

.Pacific Northwest...
Considerable and widespread small stream and moderate-to-major river
flooding is ongoing across the western Cascade Foothills to the Puget Sound
region in WA. Isolated small stream and minor-to-moderate river flooding is
also occurring elsewhere in WA into northwest OR and is expected to
continue through Friday as a prolonged rain event impacts the area. Soils
are saturated, and daily rainfall through the week will further prime the
hydrologic environment. Given these saturated conditions, landslides in
steep or mountainous terrain are possible as heavy rainfall persists. Many
rivers and streams are forecast to experience multiple peaks throughout the
week as successive rounds of rainfall move through the basins. While the
magnitude and extent of responses will continue to fluctuate with the
timing of precipitation, confidence in Considerable flooding impacts
remains high.

.Northern Rockies...
Periods of rainfall and snowmelt this week are expected to generate urban
and small stream flooding across portions of northern ID and southwestern
MT through Thursday, with isolated minor river flooding also possible.
Elevated temperatures are accelerating snowmelt at low-to-mid elevations,
and this rapid melt, combined with the additional rainfall, will trigger
small stream and river responses as soils are already nearing saturation. A
Limited impacts area remains in place across the region due to the forecast
rainfall and potentially significant snowpack loss, up to 2 inches of SWE,
over the next several days.

.American Samoa
Flash flooding will remain possible through at least this evening (local
time), and additional heavy rainfall later this week may renew the flooding
potential.

//RMF

Additional National Water Center products are available at
www.weather.gov/owp/operations

$$