Hydrologic Outlook issued February 20 at 2:46PM PST by NWS Portland OR

ESFPQR

An series of frontal systems will bring heavy rainfall to northwest
Oregon and southwest Washington this weekend. Rain will begin
Saturday afternoon, and intensify overnight through Sunday. This
will lead to rises on rivers and creeks, especially along the coast
on February 22nd through the 23rd. Main stem rivers may be delayed
to respond, and flooding may occur beyond this time frame.

There is around a 25% chance of the Wilson River, the Grays River,
and other localized quick responding coastal rivers of reaching
minor flood stage on Sunday. Confidence in flooding is low as the
location of heaviest precipitation will greatly depend on where the
warm front sets up. In the case that this system over performs, more
widespread flooding is possible.

Along the Cascades heavy rainfall is expected. Heavy rain combined
with recent snow will elevate the landslide risk.

Heavy rainfall may also lead to ponding of water, general lowland
flooding, and localized urban flooding, especially in low-lying
areas or other poor-drainage areas. Heavy rainfall will also
increase the potential for landslides in areas of steep terrain and
debris flows over areas that have been burned by wildfires over the
past few years.

Shifts in the forecast storm track can change the outlook and
probabilities for river flooding, 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.