While Friday through the weekend will be wet and breezy at times, significant concern continues over the weather situation next week with the likelihood of several atmospheric river events bringing significant flooding on our area rivers.
Also, we’ll be facing an increased landslide risk even in the lowlands.
New forecast data are trending toward an onset of heavier rain on Monday afternoon, lasting into Tuesday.
There could be a brief break before more very heavy rain Tuesday night through at least Wednesday.
THIS WEEKEND
Upwards of an inch of rain in the lowlands will fall through Sunday with 2-5 inches in mountain locations.
There will be a time of snow at higher mountain locations even down to Stevens Pass late Friday through Saturday before snow levels rise again.
The rainfall will work to cause area rivers to rise, but significant flooding is not expected this weekend.
LOWLANDS NEXT WEEK
From Monday through Wednesday, we expect an average of 2-6 inches of rain to fall in the lowlands of Western Washington, with the higher of these amounts mainly south of Puget Sound.
The least amounts will fall across areas north of Everett and the northeast Olympic Peninsula.
Rainfall amounts of this magnitude will cause some urban flooding where storm drains get clogged or overwhelmed.
The risk of shallow landslides will rise next week as well.
Shallow-rooted trees could fall when soils become completely saturated.
If current projections hold, this could be our heaviest lowland rainfall event areawide since at least early 2022.
RIVER FLOODING
Extreme rainfall is expected for our mountains, starting Monday afternoon lasting through at least Wednesday.
Rainfall totals of 5-11 inches will be common in the mountains, with some forecasts pointing to even higher amounts in a few of the favored spots.
Snow levels near or above 6,000 feet means snow will fall only on the higher slopes and volcanoes.
Much of the precipitation that hits our mountains will run off into rivers.
People living near rivers or river floodplains need to review their preparedness now for significant flooding.
As of Friday afternoon, the Snoqualmie River at Carnation is forecast to rise quickly Tuesday to near major flood stage by Tuesday evening, with another crest near or slightly above major flood stage on Thursday.
If those levels are reached, it would be the worst flooding on the Snoqualmie River since March of 2022.
The Snohomish River near Monroe is also expected to near or reach major flood stage on Tuesday evening and again on Thursday, with the worst flooding since 2020.
These river forecasts are highly variable and subject to change based on rainfall trends.
The Skagit, Skykomish, Snohomish, and Cowlitz rivers are forecast to each moderate flood stage with the highest water levels from Tuesday through Thursday.
Other rivers and streams will run high or experience minor flooding, as current forecasts indicate.
It is possible the flooding risk will extend beyond next Thursday on many river systems and the landslide risk will continue for a while even after heavy rainfall ends.
Stay with KIRO 7 News through the weekend and into next week for the latest updated forecast information and live coverage of this developing flooding and heavy rainfall event.