Expect a cooler, wetter winter this year
La Nina returns for the third year in a row this winter. Going back to 1950, three consecutive La Ninas occurred only one other time, in the mid-1970s.
La Nina is when sea surface temperatures in the Eastern Pacific tropical waters – the waters west of Peru, are cooler than average. Those cooler waters adjust weather patterns in the tropics and are reflected in the mid-latitudes by adjusting the Pacific storm track.
La Nina winters tend to have the storm track spend more time at our latitude in the Pacific Northwest versus say, California. As a result, our region usually has a cooler and wetter winter season.
A Winter Weather Advisory has already been issued by the National Weather Service (NWS) for the Cascade Mountains between Whatcom and Lewis counties warning of “very difficult travel.”
A couple of inches of heavy, wet snow can be found on Snoqualmie Pass Wednesday morning, with State Route 410 closed Wednesday morning because of drivers losing traction near Crystal Village.
SR410/Chinook Pass & SR123/Cayuse Pass on the east side of @MountRainierNPS are both temporarily closed due to snow. Conditions are being assessed today 10/26. WSDOT updates:
— MountRainierNPS (@MountRainierNPS) October 26, 2022
The latest seasonal winter weather outlook was recently released by the NWS Climate Prediction Center and it reflects that cooler and wetter trend. The outlook stacks the odds in favor of cooler-than-average temperatures and above-average precipitation during the winter season of December through February.
La Nina winters often result in a healthy mountain snowpack, and that was the case the past two winters with the snowpack exceeding average depths when they peaked in the spring. In addition, La Nina winters also frequently result in lowland snow across Western Washington and that happened the past two winters as well.
La Nina winters can also result in heavy rainfall events and flooding like what happened in Whatcom and Skagit counties last November. Strong damaging wind storms are another potential La Nina by-product.
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