Hydrologic Outlook issued February 22 at 2:57AM PST by NWS Portland OR

ESFPQR

An series of frontal systems will bring heavy rainfall to northwest
Oregon and southwest Washington through Monday. Heavier rain will
begin with the arrival of a front this afternoon, and intensify
tonight into Sunday. After a brief lull in precipitation late Sunday,
another strong system will bring additional moderate to heavy
rainfall on Monday. This will lead to rises on rivers and creeks,
especially for rivers draining the Willapa Hills and Oregon Coast
Range through Monday. Main stem rivers may be delayed to respond, and
flooding may occur beyond this time frame.

There is around a 20-30% chance of the Wilson River, the Grays River,
and other localized quick responding coastal rivers of reaching minor
flood stage by late Sunday or early Monday. More widespread river
flooding is not expected, but increases in forecast precipitation
amounts could lead to additional rises on area rivers if heavier
rainfall stalls over the area for a longer period of time.

Heavy rainfall along the Cascades combined with snowmelt will lead to
an enhanced risk of landslides.

Heavy rainfall may also lead to ponding of water 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. The probability of debris flows is currently
low as rainfall rates are not expected to meet thresholds 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.