(A quick reminder that during noteworthy weather events, you can find quick updates on my Facebook weather page.  Check it anytime there is flooding, snow, wind, heat or cold – these mini-blogs contain the finer details as the event unfolds!)

Well that was fun, at least by late February standards.  In the middle of our cold blast, a weak slider system dropped out of British Columbia and gave the metro area snow, ranging from a trace to 1″.  My neighborhood saw about 1/2″ this morning, though it was mostly gone by noon.  The cover photo is of a couple Spanish irises, growing in our backyard.

Clouds broke up by early afternoon, allowing temps to rise to 41 degrees F at PDX.  That is still 12 degrees cooler than normal and only 3 degrees shy of the day’s record cold high.  Vancouver Airport topped out at only 40.  I don’t have VUO records handy, but it’s telling that a high temperature of 40 is unseasonably chilly by the time we get to the end of February.

Tonight will be our last “really” cold night, with widespread low/mid 20s.  Tomorrow the sun should warm us up to near 50, which will feel especially nice after all this cold and wind!

Weather eyes are now turning to the pattern for next week. Conditions over NW Oregon and SW Washington have been extremely dry for the past 7 weeks. That will finally come to an end, beginning late Saturday and Sunday. The Pacific jet stream will strengthen for the first time since early January, allowing storms to push into the Pacific Northwest.  At least for the first 2 or 3 days, the jet will tap into moisture from the subtropics (i.e. Hawaii). Here is the precipitable moisture map for 1pm on Monday:

That phallic-looking red column is an atmospheric river…a narrow train of heavy water vapor moving from the northern Hawaiian Islands and slamming into the Oregon and Washington coast.  This pattern is responsible for most of our heavy rainstorms.   The WRF-GFS shows hefty amounts of rainfall by the time we reach next Thursday morning:

Looks like about 1.5-2″ for the metro area, with heavier totals to our west and north (that’s been a common theme this fall and winter).  Fortunately the upper soil is much drier than normal for the time of year, so it’s doubtful we see much in the way of flooding.

By the middle of next week the rain subsides a bit, and cooler air moves over the West Coast. Long-term models are showing a lot of cool troughing in the Western U.S. as we move through early March. Today’s 12z GFS shows the upper pattern locked in 12 days from now (Tuesday, March 8):

Normally I don’t like to place too much faith in maps beyond the 7-8 day range.  But they have been fairly consistent with the “cool March theme” for the past 3-4 days.  A few of the operational maps have even shown some early March arctic air slipping back into the Columbia Basin!  That doesn’t seem like a likely outcome- chilly onshore flow is far more commonplace in March than cold easterly flow.  But it does happen on occasion. I should note that the “tilt” of the jet stream in the map above, is quite favorable for a Canadian surprise.  Anytime you see the white zone between the Pacific ridge and western U.S. trough, running from NNE to SSW.  That is ideal for allowing cold air to get lodged in the West more deeply than it otherwise might do.

I’m going to hold off on declaring our winter over for a few more days, until we have a clearer picture what the first 10 days of March have in store for us.  If it becomes obvious that we won’t see any more snow below the 1,000-foot level, it will be time to pull the fork out!

-Karl