Second of three storm systems moves
into western Washington
Flood watch and high wind warnings in effect for several counties
October 18, 2017
Flooding on Main Street in Sultan, WA in 2015 as water from the Sultan River backs up and slowly creeps eastward about a block and a half into the downtown area. Photo by Sky Valley Chronicle
(SEATTLE, WA.) -- The National Weather Service says a strong storm front will roll into western Washington Wednesday bringing with it a period of heavy rain and very windy conditions in some areas.
Heavy rain will also fall in the mountains as a moist plume of air in strong southwest winds aloft collides with the Olympic mountains and mainly the North Cascade mountains Wednesday afternoon and evening.
This is the second of three storm systems expected to hit western Washington this week.
A high wind warning and a wind advisory are in effect and a flood watch has been expanded to include portions of Northwest Washington and West Central Washington including the following counties: Snohomish, Skagit and Whatcom from Wednesday afternoon through Thursday morning
What will happen:
Computer projections say we can expect 4 to 6 inches of rain to fall in the North Cascades Wednesday and Wednesday night and that will cause rises on area rivers, including the Nooksack in Whatcom County, the Stillaguamish in Snohomish County and to a lesser extent the Skagit River in Skagit County.
If flooding does occur it is expected to be minor. The main focus of the precipitation will be on southwest facing slopes of the Olympics and North Cascades. Precipitation amounts of 5 to 8 inches can be expected in the Olympics while the lowlands of western Washington will get up to 3 inches.
During the night-time hours a few rivers in the watch area (the three named above) could rise to the point where they would touch flood stage.
Urban and small stream flooding is also possible in areas where the most intense rain falls. Those people liviong in areas prone to flooding shoudbe prepared to take action should flooding develop.
A flood "watch" means there is the potential for flooding based on current forecasts.
The heavy rainfall rates for the storm systems are accompanied by high snow levels well over 7000 feet in the mountains.
Models do not show flooding on area rivers, but rainfall will bring the river stages close enough (within a foot) of flood stage on the Skokomish, Nooksack, Stillaguamish, and Skagit rivers that flood watches have been issued for Wednesday afternoon through midday Thursday for Snohomish, Skagit, Whatcom and Mason counties in case rainfall is any heavier than currently forecast.
Lowland locations may see urban and small stream flooding due to the combination of high rain rates and drainage issues due to leaves clogging drains.
Rivers will recede later Thursday through Friday night as snow levels drop to around 3500 feet and precipitation becomes more
Rivers could quickly rise later Saturday into Sunday with the weekend storm system.