Dreams of a White Christmas finally come true

Dreams of a White Christmas finally come true
SEATTLE -- It's been a long time since everyone's had a White Christmas around here. In fact, it might have been 147 years since there was this much snow on the ground on Christmas Day, region-wide.

A Puget Sound Convergence Zone set up shop in the North Puget Sound area Christmas Day morning, then slid down through King County before beginning to fizzle out in the afternoon. Most areas reported about 2-4" of new snow on top of the snowpack still around from several snow events through the past two weeks.

We'll have to see if 1" of snow is measured at Sea-Tac Airport (looks like it will) and if so, it'll be the first official White Christmas in Seattle since 1990, and likely the largest snow depth since the 6" on the ground in 1871, or possibly the 12" on the ground since 1861. (The only other time more than 2" was on the ground was the 4" in 1965.)

The snow is just about done for the lowlands for the foreseeable future, but you won't have to travel too far if you begin to miss it, as feet of snow are forecast in the mountains this week. More on that in a moment.

Thursday night, concern changes to ice again, as skies clear and temperatures drop into the upper 20s. So all new snow and melting old snow will likely freeze, but hopefully there's enough of lingering snow or slush to keep some traction, instead of a smooth sheen of ice.

Friday starts the permanent change to rain with a warm weather storm moving our way. The day will begin dry, but rain should develop around midday to early afternoon. It's possible this might briefly begin as snow in some places, but the change to rain will be quite rapid. Highs Friday will reach the low 40s which will do a good job of melting the snow, plus this storm looks fairly wet -- about 0.50" of rain or so, so we'll have to watch for urban flooding issues.

Be sure to keep storm drains clear. Also, commercial businesses with flat roofs and drainage in the middle of the roof need to take steps to clear as much snow as possible as the weight of rain on top of snow could be too much to handle -- especially if a drainage pipe is clogged by snow and you get water pooling on your roof.

It'll be breezy too, with wind gusts to 30-40 mph, especially north, but nothing major.

Friday storm kicks off a procession of several regular Seattle-esque storms of steady rains and breezy winds that will blow through for the next week at least. High temperatures this weekend and into next week will climb back into the low-mid 40s with lows above freezing (mid-upper 30s) but the focus will turn to the mountains, which will get absolutely hammered with snow.

A WINTER STORM WATCH is in effect for the Cascades and Olympics from Friday evening through Sunday evening. Forecasts are for potentially 2-3 feet of snow alone with the storm due in Friday evening through Sunday evening, although snow levels will gradually rise from 2,500 feet Friday to 4,500 feet by Sunday, getting Snoqualmie Pass back over to rain at some point. But this has the makings of an incredible avalanche risk, so if you're planning on backcountry skiing this weekend, pay close attention to all warnings and roped off areas. It's also possible we could see intermittent pass closures due to avalanche control. So even through travel conditions are expected to improve greatly in the lowlands, mountain pass travel this weekend remains challenging.

And long range forecasts next week show way more mountain snow is in the offing. Looks like we're going to quickly make up for that dismal November snowpack :)

In the meantime, enjoy the rare snow and have a Merry Christmas!