Another Round of Flooding, Next Atmospheric River Ahead

FastCast—Monday, Nov. 29 to Friday, Dec. 3:

The weekend’s atmospheric river brought another round of flooding to Western Washington, especially in Whatcom County. A total of 0.5-1.5 inches of rain fell in the interior lowlands, and as predicted…2-6 inches fell in Whatcom County. Additionally, temperatures reached the upper 50s to low 60s on Sunday due to the subtropical component of the atmospheric river. Rain has tapered around the area as of Sunday night. The next atmospheric river will approach from the northwest, keeping areas south of Bellingham in the rain shadow (0-0.25”). Areas outside the rain shadow will receive 0.5-3 inches of rain, and 2.5-7 inches in the mountains. Temperatures will remain in the upper 40s to mid 50s through Wednesday evening. Temperatures decrease into the mid 30s to mid 40s by Friday.

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It was an active weekend across Western Washington, with yet another atmospheric river impacting the area. We experienced balmy temperatures (upper 50s to low 60s), heavy rain, and another round of flooding. Rain totals ranged from 0.4-1.5 inches in the Interior Lowlands and 2-6 inches in Whatcom County and BC’s Lower Mainland. The mountains received up to 7 inches of rain.

I went to Snoqualmie Falls on Sunday morning, and it was raging! Click here for my video on Twitter.

There is also ongoing urban & river flooding in Whatcom, Skagit, and Snohomish Counties, particularly on the Nooksack River north of Bellingham and numerous Whatcom County roads. (See Live Storms Media video). In the WSDOT map below, you can see the amount of road closures on Sunday night in round 2 of Whatcom County’s flooding.

In British Columbia, flooding continues as areas try to recover from the previous devastating flooding. Check out the SteBros YouTube channel to see daily updates from a major washout on BC Highway 5 in Coquihalla Canyon (about 75 miles east of Vancouver).

Looking ahead, another atmospheric river will move into British Columbia on Tuesday. It will move in at a northwesterly angle, putting areas from Bellingham southward in the rain shadow. Below is the UW rain forecast through 4 PM Wednesday.

The western and northwestern slopes of Vancouver Island, the Olympics, and the North Cascades will receive 1.5-7 inches of rain. Areas from Bellingham to Vancouver BC will receive 0.75-3 inches of rain. The metro area will be in the rain shadow during this event, and will receive 0 to 0.25 inches of rain. This next atmospheric river will cause rivers to rise a bit more by Tuesday after receding on Monday. Rivers that flooded on Sunday will reach minor flood stage (except the Skagit, which will reach moderate stage).

Looking ahead, below is the forecast for Federal Way from Weather Underground.

Expect light rain at times in the metro area, with temperatures decreasing by Wednesday night, as an overall colder pattern arrives.