Seattle Snow Forecast: Winter Weather Advisory, 2-3 Inches Possible

SEATTLE — Puget Sound's best shot for snow of the season so far is on the doorstep, but plenty of uncertainty is left in the forecast over just how much will stick.

Much chillier temperatures are on tap this week, with afternoon highs failing to escape the 30s in Seattle on Monday and Tuesday, and overnight lows landing right around freezing. Conditions should be cold enough for lowland snow several times in the days ahead, but a few variables will make all the difference in how wintry the weather turns — from very cold rain to a bounty of snow.

Here's some of the thinking for Tuesday and Wednesday from the National Weather Service:

"With cooler air in place, especially if the current timing holds true, expect to see some light snow to fall at onset with the moisture running ahead of the approaching warm front. Southerly low-level winds should bring a slight bump in snow levels and preclude much in the way of snow accumulations south of around Tacoma.

Meanwhile, confidence is lower for around Seattle, where the timing of the warm southerly flow arriving and the moisture leads to a somewhat tricky forecast where a few degrees in the temperature profile is all the difference between a few inches of accumulating snow and a cold 35 degree rain.

The most likely scenario for accumulating lowland snow during this time would be during periods of heavier precipitation, where enough cold air is dragged down to the surface. Snow levels are then expected to drop back down below 1000 feet by Wednesday afternoon. With colder air filtering in Wednesday the threat of accumulating lowland snow increases and will remain."

Forecasters expect precipitation chances will build Tuesday afternoon and evening, opening the door for accumulating snowfall in much of the lowlands before transitioning to rain. Another fair shot for snow will arrive late Wednesday into early Thursday, and cold temperatures will linger in the forecast into the weekend.

A winter weather advisory will be in place from 1 p.m. Tuesday to 10 a.m. Wednesday, including the cities of Seattle, Bellevue, Kirkland, Sammamish and Issaquah.

The latest snowfall probabilities vary greatly by region and appear highest in the Cascade foothills, areas north of Seattle and along portions of the Kitsap and Olympic Peninsulas. Updated odds shared Monday showed a promising chance for the Seattle area to see up to two inches of snow, while the odds are lower around Tacoma and other points south.

Forecast models continue to paint different pictures for the Seattle metro, and little fluctuations will make a big impact on how the system shakes out across the region.

As for the mountains, Snoqualmie Pass could pick up more than two feet of new snow between Tuesday afternoon and Thursday morning, adding on to an early-season boon for the Cascades, with up to 18 inches possible over Stevens Pass. At Mount Rainier, Paradise will likely pick up even more.

With frigid temperatures in place for the foreseeable future, state transportation officials are reminding drivers to plan ahead for potentially slick morning and evening commutes through the work week.