Hydrologic Outlook issued February 21 at 3:52AM 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 20-25% 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.

Heavy rainfall along the Cascades is expected and combined with
recent snow accumulation, there is elevated 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.