ESFPQR A series of frontal systems will keep conditions wet through the weekend and much of next week. The most notable period will be late Monday through late Wednesday, where a prolonged atmospheric river may bring significant rainfall and rising rivers across southwest Washington and northwest Oregon. However, river flooding for some locations could continue into Thursday and beyond as some rivers take longer to respond to heavier rainfall. Rivers draining the Coast Range and Willapa Hills have a 30-60% chance of reaching moderate flood stage and a 10-30% chance of reaching major flood stage. Additionally, many Willamette River tributaries that drain from the Coast Range and Cascades have anywhere from a 10-55% chance of reaching minor flood stage and a 10-25% chance of reaching moderate flood stage. Flooding of the Willamette mainstem rivers is unlikely to occur (less than 10%). Probabilities for specific river points can be found at the National Water Prediction Service website. There is also the potential for flooding along small creeks and streams, as well as urban flooding, including roadway flooding, for locations in the central Willamette Valley north into the southwest Washington lowlands, including the Portland metro area. Periods of heavy rain will also increase the risk for landslides in areas of steep terrain, and debris flows over recently burned areas.