Happy New Year everyone!  The calendar has shifted from 2022 to 2023, and it’s time for a quick review of the past year’s biggest weather events.  Of course our calendar system is very arbitrary and anachronistic, based on the dictates of the medieval European church; there’s nothing magical about the date January 1, roughly eleven days after the southern solstice.  But here it goes:

2022 was a year of “unseasonable” weather, first and foremost.  By that I mean that our temperature patterns in particular, were out of step with the normal timing of our seasonal cycle.  We’ve seen this theme rear its head before, especially in 2011 when we had an unusually cold spring and then our hottest weather in late August and September.  But this year took the idea to a new extreme.

Here are the 4 events that stuck out in my mind:

1.  A very wet and cool spring, with historic snowfall on April 11.  This was probably the most interesting event of the year, with most of the Portland/Vancouver metro seeing between 1″ and 4″ of snow on the ground in the morning.  We’ve seen localized snowstorms in the vicinity in March before (think of the southern Willamette Valley in 2012), and even occasional marginal snow setups in April.  But never in modern history has there been significant accumulation in the western valleys this late in the springtime.
2. Very long and hot summer, which continued deep into what is normally autumn.  Local meteorologist Mark Nelsen remarked that the April snow was about as unusual as hitting 90 degrees in mid-October would be.  Sure enough, we came extremely close to that as well!  High temps of 86 and 87 at PDX on the 15-16th of October, and 12 days 80+ in October totally blew away the old record of 6 days.  We had a total of 29 days 90+, which was a tie for 2nd place.  August, September and October were all the hottest on record at PDX.
3. Major wildfires between August and October.  There was the Cedar Creek fire in the Central Oregon Cascades and the Bolt Creek Fire in the Washington Cascades, which clogged the skies of cities like Eugene and Seattle with horrific smoke.  Portland and Vancouver got in on the smoke action in mid-October with the Nakia Creek Fire in eastern Clark County.
4. One “wild week” between December 21 and 27.  First a low-level cold blast came through the Gorge, followed by an ice storm the subsequent two days.  Then a heavy atmospheric river and moderately strong windstorm came immediately after Christmas.  More on this below…

Winter 2022-23 Progress Report

I think it’s safe to say that this has been one of the more active starts to winter that we’ve seen in recent years.  I’m not saying that other Decembers (and late Novembers) have all been boring; December 2021 was fairly active as well, and there was also quite a bit of snow and cold in 2016.  But this year, it was very obvious that we turned the corner from fall to winter immediately after Thanksgiving, and haven’t looked back since.

Here’s what we’ve seen so far this winter:

• Lots of chilly valley rain, and heavy Cascade snow.
• A “marginal” snow setup on December 4, with cool east wind and evaporative cooling allowing flakes to fly in the entire metro area.  Accumulations were minor at the lowest elevations, though.
• A significant cold spell from December 21-24.  Temperatures stayed in the 20s all day at PDX on the 22nd & 23rd, the first time that has happened since the brutal 2016-17 winter.
• A paralyzing ice storm from the evening of 12/22 through midday on 12/24.  Between 1/4″ and 1/3″ of ice accumulated on roads, snarling travel and even disrupting mail delivery for a day and a half.  Luckily ice totals weren’t enough to cause serious damage and widespread outages like February 2021, but it was still a major headache for people and their Christmas plans.
• A heavy rainstorm on the 26th and 27th, with 3-4″ dumping across the Metro area and causing minor flooding along roads and some streams.
• A moderate windstorm on the 27th, featuring 45-55 mph gusts locally and upwards of 70 mph along the Oregon coast.  The heavy rain immediately beforehand made treefall & outages significantly worse than they otherwise might have been.
• Temperatures in both November and December have been on the chilly side.  November was 3.4 degrees F below normal at PDX, and December saw a -2.6F departure.  That’s not extremely cold by any means, but it’s a far cry from some of the positively balmy Novembers and Decembers we’ve seen over the past several seasons.

About the only things we haven’t seen this season are:

• A significant snowstorm in the Metro area (widespread 2″ or more); and
• A major arctic blast with nighttime temps in the teens or single digits for several days.

So to put it in perspective, our “Active Weather Glass” is already at least 70-80% full, and we’re not even halfway through winter yet.

What’s in store for us as we move into January?  The Pacific jet stream and storm track looks to remain very active, but now the bulk of the rain has shifted south into California where they are seeing semi-historic rainfall totals.  San Francisco just recorded its second wettest day in history on December 31, and more heavy rain is on the way over the next few days as another atmospheric river takes aim at the Golden State.  The cover image for this blog shows the jet stream over the Pacific Ocean.  It is “zonal,” meaning very strong upper-level winds from west to east.  This is a good pattern for getting a parade of storms along the West Coast of North America, but it is not a good pattern for any sort of cold air dropping out of Canada.

A low pressure system over the Pacific is currently “bombing out” (strengthening very rapidly), and is expected to drop as low as 955-960 mb at the surface.  IF it were closer to the Oregon coast, we would be in for a severe windstorm tomorrow into Thursday.  Fortunately it’s far enough south and west that the wind impacts in our area will be relatively minor.  Northern and central California will not be so lucky, with 50-75 mph gusts expected on top of water-logged soil.

Here in the Pacific Northwest we will remain relatively wet over the next 7-10 days, but probably no heavy flooding rain.  And there’s no sign of snow or cold air in sight.  That could change as we move into late January or February, of course, but it’s too early to tell.  For now, the big story is going to be torrential rains in California.  I’m not sure if this qualifies as a historic “megastorm” along the lines of 1861; we won’t know that until we see just how many more rainstorms they get over the next couple weeks.  But this is a fairly exceptional wet pattern.  Ironically, California’s saving grace might just be the terrible drought conditions they have experienced over the past few years.  Reservoirs and groundwater are low enough that heavy rain won’t result in the kind of deep flooding they might have seen in the past few winters had seen normal to above-normal rainfall.

Karl