Cold weather and January 6 go together like peanut butter and chocolate, I guess.
Exactly one year ago was the last time the western Washington area battled a wintry mix of snow, ice and freezing rain. We've changed the "04" to "05" and lightened up a bit on the intensity. (Interestingly enough, we just noticed the record high for the day was 57 degrees -- set in 2003. So I guess we're making up for that?)
Anyway, the only 57 associated with this forecast might be the time it takes you to get 2 miles on the roadways this weekend as now more snow is in the forecast for Friday night than originally thought -- there's even a WINTER STORM WATCH in effect for the greater Seattle area! More on that below.
Most of the area was in rain this evening, except for areas in Skagit and Whatcom Counties and the higher foothills, and that will continue to be the case overnight. Speaking of which, let's go around the horn:
Up north, a WINTER STORM WARNING remains in effect until midnight for western Whatcom County (Lynden, Ferndale, Bellingham, Sumas, etc.). Up to 5 inches of snow are possible, with the highest accumulations away from the water. We're also seeing a couple of inches in northern Skagit County on Bow Hill. Near the water, just a little accumulation.
Elsewhere, just rain showers or perhaps rain and snow mixed overnight moving north to south as that arctic front slides south through the area. Light snow showers above 700 feet or so toward the northern Cascade foothills. (4 inches in Baring reported as of Thursday evening.)
A lull in the precipitation is expected after midnight, with just a few isolated showers around the area. Lows tonight are only expected to be around 30-33, so we're not expecting the hard freeze like Wednesday night. Still could be slick in the foothills though, where lows will drop into the upper 20s.
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The next phase in our little winter weather extravaganza is for that trough of low pressure to continue to move south offshore Friday morning, (and that low has become stronger than previously thought) and this is where the forecast gets into a bit of a yo-yo phase.
That low might kick some moisture from whatever's left from the front back our way early in the morning.
Again, to recap the important factor in this forecast: At face value, this pattern as a whole is not cold enough for snow. But the wild card is that cold, arctic air sitting behind the inland B.C. mountains and, to a lesser extent, in eastern Washington. Even though if we were to have zero wind, we'd be too warm to snow, that low is likely to pull some of that arctic air both through the Fraser Valley and through the Cascade mountain passes. (This is explained in Scenario 1b on our Snow Scenario Weather FAQ)
But how much cold air and when is the key to the snow. OK, got that? Let's move on to Friday...
FRIDAY EARLY MORNING
It's possible that the few leftover showers that are still around could change back to light snow toward morning as the temperatures fall back toward that 32 degree mark (scenario 5 in the Weather FAQ). Any accumulations are expected to be an inch or less -- maybe 1-2" over toward the Hood Canal area. (That is Scenario 4 on the FAQ)
Once we get into the daylight hours Friday, we begin the battle of daytime heating versus that cold air seeping in, all the while with that low tossing some showers our way at times.
Thus, the day could be a hodgepodge of snow and rain, as the sun tries to warm us into the mid-upper 30s, while that cold air tries to come in from parts north and east. The best chances of snow during the day will be north of Seattle (maybe an inch), as well as the Hood Canal area and up north of the Skagit/Snohomish County line, where a couple of inches are possible. The worst chances are south of Seattle where you'll have to wait longer for the cold air, and any showers should be rain.
FRIDAY NIGHT -- SNOW LOVER'S NIGHT
By Friday night though, it looks like everyone gets in on the snow fun.
The latest computer models have that stronger low pushing in another stream (and a good dose at that) of moisture overnight Friday. Combine that with that low having more power to draw in more cold air, and it's a good recipe for snow for everyone.
A WINTER STORM WATCH (yes, that sounds impressive, doesnt it?) is in effect for all of the interior of Western Washington between Olympia and the Canadian border for Friday night and Saturday morning.
The exact timing is still a little variable, so we're going generally Friday night, but it should be after the commute.
Generally, we're thinking this will put down 2-4" of snow across the area -- perhaps a little more in the foothills and north. Lows will be around 30.
On the Seattle Snow Freak Out Scale (TM?) of 1-10 (10 being Minnesota), I'd now put Friday night at a 4. It might have rated a 5 or 6 if there had been a commute Saturday morning :)
That low drifts off to the south, taking its moisture away and leaving us with decreasing snow showers. Highs will only be in the low-mid 30s. So bundle up if you're going to the Seahawks game (wouldn't that be fun if it snows during the game? St. Louis is a domed team, you know .)
Saturday night and Sunday is looking dry and cold. Lows Saturday night will drop into the low-mid 20s, so plenty of ice concerns still exist. Sunday will get to the mid 30s as we do expect some sunshine.
So, for those trying to gauge when to go back to Pullman for start of classes there, Sunday might be your best day for western Washington and the passes, but it'll be icy in Eastern Washington no matter what, so take it easy.
Our next bout with snow comes in the form of another arctic front Monday afternoon into Tuesday. Again, we're not dealing with huge amounts of moisture (if you look at that Snow FAQ under 1a -- both today and Monday we'll be dealing with the "this track too far inland" scenario) but still some snow showers likely.
The long range models still bring even colder air behind that front for Tuesday through the end of next week. It's still early, and they've advertised this cold air before (like, for today and Friday in last weekend's models) so it's not a slam dunk, but they have been consistent.
As for January 6, 2006, what do you think? 58 degrees? :)