Monday saw record rainfall, and a landslide canceled Sounder commuter-train service from the North End.
A succession of storms through midday Wednesday is forecast to drench portions of Washington, with up to 11 inches of snow-melting rain falling in the Cascades and Olympics, increasing the chance of flooding and landslides.
“It’s a one-two-three punch of systems, and we don’t get much of a break,” said Kirby Cook, National Weather Service meteorologist. “It looks like a fire hose coming in off the Pacific.”
National Weather Service meteorologists say the warmth of the weather systems increases threats of flooding and mudslides, carrying precipitation they expect will heighten snow levels and create hazardous driving.
By 8:30 p.m., Monday had become the wettest Dec. 7 on record at Sea-Tac International Airport, with 0.97 inches of rain since midnight. The previous record was 0.88 inches of rain all day on Dec. 7, 1968.
The Seattle area has had nearly 3.2 inches of rain since the beginning of the month. The average rainfall total for the first week of December is 1.35 inches, according to the weather service. From midday Monday through Wednesday, rainfall could hit 2 to 3 inches in parts of the Puget Sound area.
In Western Washington, the snow level could reach as high as 8,000 feet Tuesday. That means rain on the newly accumulated snow could swell rivers already running high.
“The rivers don’t get much of a chance to drain off before the next front comes through,” Cook said. A flood watch has been issued for much of Western Washington.
Minor to moderate flooding is expected in most rivers on the Olympic Peninsula and on the west slopes of the Cascades.
Cook said the forecast contains a trio of wet weather systems: the one that arrived Monday, another during the morning commute on Tuesday and a third Tuesday afternoon.
Tuesday’s forecast also calls for high winds throughout Western Washington, boosting the likelihood of power outages. In the Seattle area, sustained winds of 15 to 30 mph and gusts up to 40 mph are predicted.
The forecast for the Seattle area calls for rain — at least in the form of showers — each day for the next week.
Sound Transit canceled Northline Sounder service for the upcoming days late Monday after debris and a tree blocked tracks. The transportation agency expects service to resume Thursday morning.
In Eastern Washington, meteorologists are closely monitoring rainfall in areas impacted by this summer’s wildfires, or places with burn scars, where the added precipitation creates risk of slides and flooding.
“Now that the ground is really saturated, and we’re going to pile more rain on top of that, that increases the potential for debris flow, trees falling over,” said Laurie Nisbet, a Weather Service meteorologist in Spokane.
Nisbet said forecasters are watching the area where the Okanogan and Chelan complex fires destroyed hundreds of thousands of acres of range and forest, for example.
Portions of Eastern Washington are under a flood advisory until Thursday, with 2 to 4 inches of rain expected in the mountains.
On the Washington coast, the storms are expected to compound the effects of high tides Tuesday and Wednesday, worsening beach erosion and overflowing into some areas near the water.
Meteorologists predict midday Monday through Wednesday rainfall on the coast to reach up to 5 inches.
For skiers, the good news is that the snow level is expected to drop after Tuesday, with snow back in the forecast for ski areas before the end of the week.