Hydrologic Outlook issued December 26 at 12:15PM PST by NWS Portland OR

ESFPQR

A series of systems will continue the wet weather pattern of late
across northwest Oregon through the weekend. This will lead to rises
on rivers and creeks through at least Sunday, December 29th. There
is currently a 30-50% probability that several rivers in northwest
Oregon including the Siuslaw River, the Mohawk River, the Marys
Rivers, the Luckiamute River and the Pudding River will reach minor
flood stage over the next week.

Heavy rainfall may also lead to ponding of water, general lowland
flooding and localized urban flooding, especially in low lying areas
or other areas with poor drainage. Heavy rainfall will also increase
the potential for landslides and debris flows in areas of steep
terrain.

The exact track of these upcoming storms will influence rainfall
amounts, and thus the potential for flooding. There is a 10% chance
that the southern Willamette Valley receives 2-3″ of rain and the
adjacent higher terrain of the Coast Range and Cascades receive 3-5″
of rain late Saturday into early Sunday. This scenario would likely
produce more widespread flooding issues. Shifts in storm track
can change the current outlook, so be sure to monitor
weather.gov/portland for the latest weather updates, as well as any
watches, warnings, or advisories that may be issued. To view the
latest river forecasts, visit water.noaa.gov/wfo/pqr.