More flooding ahead: Atmospheric river to bring warm rain, high winds, and rising rivers

What is it about mid-December weather? The latest hazardous weather has been warm, heavy rain, resulting in widespread major flooding and landslides.

During the same time period, back in 2006, the Hanukkah Eve Wind Storm struck Western Washington. On the evening of Dec. 14 into early Dec. 15, the storm plowed through the region with southerly wind gusts up to 100 mph.

Thousands of trees fell, knocking out power to over 1.8 million people and producing hundreds of millions of dollars in damage. The storm destroyed about 70% of Puget Sound Energy’s infrastructure. Some people did not get their power back until Christmas Day.

The storm resulted in 15 fatalities, four of them directly from the storm, and 11 afterwards from carbon monoxide poisoning. Thanks to the cold and lack of power, some people used barbeques and other heating and cooking elements indoors, causing the tragic post-storm deaths. Hundreds were also poisoned.

Warm rain returns Monday

Now, another warm, wet storm will dump more rain on Monday and Tuesday this week. Most rivers have receded, yet the renewed rain will push rivers higher. Most will remain below flood stage, but the Skagit, Skykomish, Snoqualmie, and Snohomish Rivers are expected to rise to moderate flood levels once again on Wednesday, but below the high levels from late last week.

The Stillaguamish, Skookumchuck, and Cowlitz Rivers are anticipated to exceed minor flood levels. The White and Green Rivers are forecast to remain above flood stage through the week.

Monitor the latest river and flood conditions on the rivers and lakes page via NOAA’s National Water Prediction Service. The threat of more landslides will remain elevated as well.

High temperatures on Monday will be about 15 degrees above normal. A number of Western Washington locations could potentially reach 60 degrees. The record high at Seattle-Tacoma International Airport (SEA) and Olympia is both 63 degrees, set in 1980.

Windy Monday

This system will also produce blustery winds later Monday into Monday night. Along the coast, wind gusts are expected to range from 40 to 55 mph. For the north interior from about Everett northward, gusts are forecast to peak between 30 and 50 mph. Further south, including Seattle, Tacoma, Bremerton, and Olympia, wind gusts should reach 25 to 45 mph.

Given the soggy soils, these winds will be capable of knocking down trees or limbs. Prepare for the potential of power outages.

If there was a silver lining from the recent seasonably mild weather, heating costs were lower.

Much cooler weather ahead

The good news to end this period of rainy weather and the flooding is a big change in the overall weather pattern that will unfold mid-week. A much cooler air mass is expected to arrive from the Gulf of Alaska following a cold front Tuesday. Snow levels are forecast to tumble to around 2,500 feet Wednesday.

Showers the rest of the week will result in mountain snow piling up. Up to two to four feet of new snow is forecast through Thursday, with more anticipated heading into the coming weekend. Motorists planning to cross Cascade highways should expect winter-weather driving conditions. Be sure to at least carry chains in case road conditions require them.

The big change in the weather pattern will also allow rivers to finally fully recede.

In Western Washington, temperatures will be much more seasonable starting Wednesday, only in the mid-40s to near 50, while lows will range from the mid-30s to mid-40s.

This weekend and beyond

Looking ahead to Christmas Day and toward the end of the month, the weather outlook calls for cooler, wetter-than-average conditions. For those wishing for a white Christmas, the mountains will do the trick, with wet weather anticipated for the lowlands of the region.

Ted Buehner is the KIRO Newsradio meteorologist. Follow him on X and Bluesky. Read more of his stories here.