Examining Upcoming Chances of Lowland Snow

FastCast—Tuesday, Dec. 14 to Thursday, Dec. 16:

After an active weekend, we have calmed down (and cooled down), and multiple slight chances of lowland snow are possible this week. The best chances of lowland snow will be Monday night/Tuesday morning and Tuesday night/Wednesday morning. Both these times will have marginal chances for snow, with very light and brief accumulations possible. The best chance of snow will be on the Kitsap Peninsula and along Hood Canal. Areas on the Olympic Peninsula and from Olympia westward also have a chance for light snow. In the metro area, the best chance of snow will be where heavier showers set up. Heavier showers drop the snow levels and mix snow and sometimes ice pellets down to the surface. Generally, the best chance of snow will be on higher hills. Regardless of if it snows, there will be rain showers, with 0.2-0.7” of rain by Wednesday evening. It will also be chilly, with highs in the low 40s and lows in the low to mid 30s. Additionally, the mountain passes will receive 4-6 inches of snow by Wednesday as well.

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Continue reading the full blog below!

Western Washington is stuck in a persistent cold pattern, and with such patterns inevitably will come some chances at lowland snow, as is the case this week. 

As usual in Western Washington, your chance at seeing snow depends greatly on location. This blog will examine several forecast models for snowfall (not necessarily the same amount that sticks) through Wednesday night. 

The highest probabilities for snow showers are Monday night/Tuesday morning and Tuesday night/Wednesday morning. These chances are marginal, at best.

Let’s start with the Euro model. This is the most favorable for Western Washington snow, showing at least a dusting around the area by Wednesday evening. The Euro thinks most of this snow will fall Tuesday evening in the lowlands.

This, however, is just one forecast. Next is the high resolution HRRR forecast for the same time (through Wednesday night).

The HRRR shows no snow south of Seattle, but some accumulations between Seattle and Mount Vernon. 

The high resolution NAM model (below) shows a relatively similar picture as the HRRR does. 

The NAM shows some spotty accumulations between Seattle and Tacoma and from Everett northward.

Looking through the models, there are some consistencies. Expect at least 0.5” of snow on the Kitsap Peninsula and along Hood Canal. There is also a chance of snow from Olympia westward, according to the forecast models. The I-5 corridor is the big question mark.

For the metro area, below is a helpful graphic from NWS Seattle showing the probability of at least 0.1” of snow through Thursday night.

This is quite helpful in showing just how marginal all these snow chances are…but for the snow lovers out there…extended forecasts are showing more potential snow probabilities, including around Christmas, so stay tuned!

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