Flooding is looking more likely for some rivers in Snohomish County and others in Western Washington, according to the National Weather Service.
A flood watch, beginning at midnight Saturday night and expected to continue through Monday evening, has been expanded to include seven counties, from Thurston County near Olympia to the Canadian border.
Flood warnings will be issued if flooding is imminent.
Minor flooding is predicted late Sunday and early Monday on the the Stillaguamish River near Arlington, when it is expected to rise to more than 15 feet.
Flooding at that height can cause water over Highway 530 at Oso and flooding in Swede Heaven area east of Oso.
Minor flooding is expected on most Western Washington rivers, said Johnny Burg, a National Weather Service meteorologist.
Moderate flooding is predicted on the Snohomish River on Monday afternoon and evening, when the river is expected to rise to slightly more than 27 feet near Snohomish. The river bank is full at 25 feet. Dike monitoring begins at 27 feet.
Predictions of some flooding follow the heavy rain that is expected to fall between Saturday evening and Sunday morning, Burg said.
“With the high snow levels in the Cascades, the mountains could see 3 to 5 inches of rain,” he said. “That will run off into the rivers and make the rivers rise.”
The heavy rains could trigger shallow, or smaller landslides, particularly on steep hillsides, he said.
Snohomish County provides real time flood information here.