The longest stretch of snow in several decades figures to extend a bit longer through Christmas Day now as another storm coming in Wednesday figures to add a few more inches to our already impressive snow totals.
A Winter Storm Warning has been issued for many areas, with a lesser Winter Weather Advisory in effect for the main Seattle-Tacoma area. (I know many were dreaming of a White Christmas, but can we switch to sugar plums or something else now?)
The rest of Tuesday will remain calm and cloudy with a few flurries as highs climb into the mid 30s. That should at least melt a sliver of the snow away, and we can use all the help we can get.
Wednesday/ Christmas Eve will feature a one-two punch. Just after midnight Wednesday morning, we expect a very weak trough of low pressure to move through the area, bringing some areas of light snow to the region (could be hit-and-miss) with about 1" of new accumulation in the passing showers.
Then, around mid-morning, a stronger storm comes inland to our north. This will spread moisture over the cold air still stuck in place here. That should mean what falls will start as snow.
As we get into the early afternoon, warm air will begin scouring out the cold air and snow levels are expected to rise to about 500 feet in the metro area. That should change the sea-level areas to rain, but the cold air will be more stubborn up north, and also elevation will keep snow going in the Cascade foothills above 500 feet.
A WINTER STORM WARNING is in effect for western Snohomish, Skagit, and Whatcom County areas (basically the general I-5 corridor from Lynnwood north to the border), and the Eastern Puget Sound foothills (basically, anywhere east of Lake Washington above 400-500 feet) from late tonight through Wednesday evening. We could see as much as 2-6" of new snow up here.
The warning is also in effect for the Hood Canal area for as much as 3-7" of new snow.
For the greater Seattle -Tacoma area, southwestern Washington, and northern islands we have a Winter Weather Advisory in effect for the same time frame. Here, accumulations are expected to be around 1-3" before the change to rain.
But we still can't shake the cold, as cooler air will move back in on Wednesday evening, likely dropping the snow level back to sea level again. In the storm's wake, we'll see scattered hit-and-miss showers that could be quite intense as the atmosphere becomes unstable Wednesday night through Christmas Day.
New accumulations with these storms will be quite variable depending on whether a shower finds its way to your home and how long it sticks around. You could get anything from 0 to 3-4".
Snow showers taper off Christmas Night.
Friday will see a warmer storm and is finally the knight that slays the snow dragon. It might briefly begin as snow, but should change to rain fairly quickly and stay that way. The rest of the weekend will feature rainy and breezy conditions, with highs in the 40s. I'll have to check and see if any outdoor swimming pools will be opening :)