Stormy weather into 2021

All signs point to a very active week or two of weather starting right about now – very classic La Niña look with 20-40 inches of mountain snow over the next seven days, possible urban and (minor) river flooding and gusty winds at times.

SNOW: A Winter Weather Advisory is in effect for the Cascades and Olympics through Wednesday. Six to 12 inches of snow will be common at Stevens and Snoqualmie Passes (possibly mixing with rain Wednesday morning) and more than 18 inches possible above 5,000 feet at the ski resorts. I expect pass travel to deteriorate tonight through tomorrow but closures and blockages (if they occur) will be more due to drivers spinning out than the snowfall rates. Still, the start of some real quality snow that will keep coming into the new year. Snow will taper by Wednesday evening and pass travel will be a little better Thursday and into Friday.

WIND: A Wind Advisory is in effect north/west of  Everett this evening through Wednesday morning for wind gusts of 35-45mph. Outside of the advisory – including around Puget Sound – we’ll have some wind gusts in the 20-35mph range. Nothing unusual or terribly impactful, but with driving rain, it will produce poor visibility particularly at night.

RAIN: Heavy rain this evening through tonight with two to three inches at the coast and an average of about an inch through Wednesday around the Sound. This rate of rainfall will probably produce some urban flooding which is difficult to spot at night and can cause drivers to get into trouble, with that danger persisting throughout the morning commute. Sunrise Wednesday is at 7:57am. Given the relatively-low snow levels in the mountains, no river flooding is expected.

THURSDAY-NEW YEARS DAY: A relative lull in the rain and mountain snow Thursday through Friday morning but it won’t be totally dry. Rain will pick up late Friday into Friday night and eventually, so will some snow in the mountains.

SATURDAY: This could be the most impactful stormy period of the next week with heavy rain, heavy rain and snow in the mountains (snow levels above Snoqualmie Pass) and strong winds around Western Washington. The exact strength of the winds Saturday are still unclear but this second system moving through Saturday looks to have enough punch to be more of a threat to cause some power outages and given the heavy rain and soggy ground, some tree damage or fallen trees. We’ll see how this develops as we get closer to the weekend.

SUNDAY and beyond: Rain continues Sunday with snow in the mountains, but given the rain on Saturday, some of our rivers will be spiking higher but no major flooding is expected. The more rainy days we have, the greater our chances of landslides around the area.

We will probably have more rain and mountain snow beyond Saturday and Sunday – it looks pretty wet and wintry for days beyond that. Right now, lowland snow doesn’t look apparent in the long-range outlook but that is subject to change given the active weather pattern and our point on the calendar. January and February is prime lowland snow season, particularly in a La Niña winter.

Cox Media Group