Seattle's zany 48-hour forecast: Warm rains, chilly snows, icy sun

Seattle's zany 48-hour forecast: Warm rains, chilly snows, icy sun
Travelers brave the weather while driving through Snoqualmie Pass, Dec. 1, 2013.

SEATTLE -- Late autumn in Seattle can range from warm, drenching Pineapple-express type rains to an arctic chill that can bring a dusting of snow.

But rarely do we go from one end of the spectrum to the other -- in just a few dozen hours!

First was the warm rains. A strong storm tapped into some tropical moisture near Hawaii and is bringing a heavy rain to parts of Western Washington on Sunday. While the main Seattle/Puget Sound area was protected from the Olympic Rain Shadow, about 2-3 inches of rain fell in the Cascades and Olympics.

It was enough to bring some minor flooding to the Puyallup River and a Flood Watch remained in effect for all mountain-fed rivers in King, Lewis and Pierce counties through Monday afternoon.

It will also be quite blustery with winds gusting to 30-40 mph Sunday through Sunday night. Sea-Tac Airport hit a gust of 41 mph at 8 a.m.

And don't forget the "warm" part. Seattle hit 56 degrees at 8 a.m. Sunday -- just one degree short of the record high for the day as the warm, tropical moisture moved through.

And that's all just part one.

Once that storm passes Sunday night, winds will rapidly shift from south to north as a very cold arctic air mass will push from the Gulf of Alaska during the day on Monday. It'll make for a very weird and unusual day where the high temperature in the upper 40s or so will likely occur before sunrise, and temperatures will drop rapidly through the day as the cold air spills into Western Washington.

What's changed a bit is that the moisture seems to be a bit further ahead of the bulk of the cold air so snow levels will likely only be down to about 400-500 feet Monday morning when there is moisture still lingering, and we'll likely be dried out by the time the snow levels falls to sea level later in the evening.

The best chances of a little snow in the Puget Sound area remain the Convergence Zone areas from about North Seattle to Everett, especially those areas above 400-500 feet away from the water. Could see a trace to 2" of slushy accumulations there Monday morning to midday. (Leaning more toward trace. Most computer models don't really paint much of any accumulations.) The Cascade foothills could also see a little snow above 500 feet in random showers.

For the rest of the Puget Sound area, snow fans have to peg their hopes on random snow showers or that the Convergence Zone becomes more intense than models currently indicate -- which can happen as convergence zones can be very unpredictable, but at this point, odds are low for a significant event.

Outside the Puget Sound area, the best chances of a little snow are in Whatcom County near the outflow of the Fraser River Valley, and the northeastern Olympic Peninsula area from Sequim east along SR-104 or so and around to Chimacum as you get some upslope flow off the Olympic Mountains from the Fraser River Valley winds. None of those places are expected to get a lot of snow -- just the best shot to get a light accumulations.

Bottom line: This is not a big snow event, and for many of you, it won't be any kind of snow event. But remember, while snow gets the most attention, it's the ice that can be the most treacherous.

It's important to remember is that the temperatures will keep dropping as the evening/night progresses, so icy roads are a real concern where any snow does fall. There is also the big Monday Night Football game in Seattle and while CenturyLink Field is south of the traditional Convergence Zone location, a few flurries there are not out of the question. And those traveling from places that might have received a little snow may find a surprisingly more difficult drive home than you encountered near the stadium.

Temperatures will keep slowly falling through the night, dropping into the mid-upper 20s by dawn Tuesday.

Also want to mention that it is also expected to be quite windy Monday and Tuesday in the Whatcom/San Juan County areas where strong winds will blow out of the Fraser River Valley, perhaps gusting as high as 40-50 mph. That will make for bitter cold wind chills.

That's all part two.

Once this storm passes, the skies will clear and the sun will shine, but it won't help a whole lot as a massive arctic air mass will dig its claws into the region. Temperatures probably won't budge much from the mid-upper 20s during the day Tuesday, maybe reaching the freezing mark if we're lucky. It'll also remain breezy in the Puget Sound area and very windy up near Bellingham so wind chills will be a factor once again.

We hold in this sunny but bitter cold pattern through the week, with highs in the upper 20s to low 30s and lows in the teens to low 20s. (Bellingham area might even be a good 5 degrees cooler than those levels.)

Long range models differ on what comes next. One model gradually warms us up into the low 40s over the weekend; others suggest another cold system may bring a second round of snow. We'll be watching closely.

In the meantime, keep dry, then keep warm, and keep safe on the roads!