A strong atmospheric river will bring widespread rain and wind this week, prompting National Weather Service forecasters to issue flood warnings for the southern Willamette Valley.
Consecutive waves of heavy rain are expected Monday through Wednesday, with 1.5 to 2.5 inches forecast across the southern Willamette Valley and 2 to 4 inches along the coast from Florence to Newport. The Coast Range could see 6 to 12 inches of rain. Lighter but steady rain is likely to continue into Thursday, keeping soil saturated and waterways rising.
The prolonged rain will push the Willamette River higher in Eugene and Springfield. Forecasters warn the river can keep rising for hours or even days after the heaviest rain ends, because it takes longer for all the runoff to reach it.
Several nearby streams and smaller rivers that flow into the Willamette River have a 40% to 60% chance of rising high enough to spill onto banks and low-lying areas — what forecasters call minor flooding. Urban flooding is also a concern in low areas of Eugene and Springfield, as creeks swell and storm drains clog with debris…