WHATCOM COUNTY, Wash. — Forecasters with the National Weather Service Seattle office say a Flood Potential Outlook has been expanded to include Whatcom, Skagit, Pierce and Clallam counties. This is the result of an atmospheric river that is expected to bring heavy rainfall to the area beginning early Friday and continuing through early Saturday.
Forecasters note that recent rainfall events have increased river flows and soil moisture levels which increase potential flood threats.
Forecasters, speaking to the western Washington forecast, said a period of moderate to heavy rainfall is expected late Thursday night through Saturday morning. Total precipitation expected during this time period ranges between 4 and 6 inches in the mountains and around 1 inch in the lowlands.
Forecasters said the Nooksack River level is expected to rise significantly but is currently not expected to reach flood stage.
Snow levels at the front of the system will be between 6,000 and 7,000 feet before falling rapidly Saturday.
The heavy rains are expected to move south by Saturday afternoon. Snow levels will drop significantly through the weekend and early next week as a much colder airmass sets in.
Rivers will be receding and the threat for river flooding will significantly decrease as attention turns more to mountain snow accumulation. The lowlands are likely to experience periodic shower activity.
River level forecasts can change frequently so drivers and property owners are advised to monitor the Nooksack River level forecast.