Arctic Air Mass moved in Sunday afternoon.

Note: Travel day recommendations at the bottom!

We started cold Monday morning but those of you in tune with the weather might have noticed the cold wind that blew in around 3PM on Sunday afternoon. This was pretty clearly the arrival of the Arctic airmass over us!

As I noted on Mastodon last night you could see it in the temperature and wind graphs on the Home/Almanac page. Below are the Wind Direction, Speed/Gust, and Temperature/Dewpoint.

24hr Wind Direction over time on Sunday Dec 18 at 21:00
24hr Wind Speed over time on Sunday Dec 18 at 21:00
24hr Temperature and Dewpoint over time on Sunday Dec 18 at 21:10

Notice the temperature was quite steady through the night and into the morning around 0.5ºC. It then dipped down to just below zero after 9AM when the east-north-easterly wind first picked up around 9AM. It then settled for a bit through midday but strong NE wind started just before 3PM and drove the temperature down from -1ºC at 3PM to -4ºC and dropping by 9PM.

We settled around -5ºC. But check out the windchill and basically due-North steady wind overnight and this morning! (You can treat the “Humidex” as regular Temperature)

24hr Temperature and Dewpoint over time on Monday Dec 19 at 10:30
24hr Wind Direction over time on Monday Dec 19 at 10:30
24hr Wind Speed and Gust over time on Monday Dec 19 at 10:30

Cold – Snow – Colder – Snowier

It was snowing lightly in Port Alberni when I left at 6:15 and it was snowing all the way to Nanaimo. It is continuing to snow now. There is a Winter Storm Warning in effect for most of Vancouver Island.

Here is the text:

Snowfall Accumulations: Near 20 cm, and possibly more in southern sections and localized areas.

Remarks: A low pressure system will make landfall in Washington State tonight. The associated front will brush through the very southern part of British Columbia giving another round of heavy snow starting late this evening.

Snow will taper off Tuesday near noon on Vancouver Island and Tuesday afternoon on the mainland side.


As it says in the warning, this snow should continue into Tuesday.

Heaviest snowfall in Port Alberni Monday night/Tuesday morning.

The snow will fall the most this afternoon and overnight. Expect the heaviest accumulation in Port Alberni just before it stops around 4 or 5AM Tuesday morning.

People on the West Coast might get some very chilly winds along with it. We might have a little of that on the Island as well.

The image below shows the snow should end by 7AM in Port Alberni and points north of Parksville on Tuesday, but the South Island and Vancouver will get hit a little longer. The low is coming onshore on the extreme north tip of Washington. Looks they’re in for a blast!

Very cold Wednesday morning

Tuesday will be chilly, but expect the temperatures to dip even more overnight on Tuesday and into Wednesday morning. This picture for Wednesday morning has us at -13ºC or lower. Environment Canada is predicting -12ºC. Either way, it’s darn cold. If you can’t drain and close your outside taps you might want to let them drip so they don’t burst!

Oh we’re not done yet. Big Snow Thursday!!

Oh but it gets better!

On Thursday we will be facing a much larger Pacific front coming off the Ocean that will impact the entire West Coast of BC. It will bring snow to the entire Island and, since it’s a pacific system, that system will probably focus on Port Alberni. The model agrees, with the strong precipitation in the Alberni Valley and Port Hardy.

There will be strong winds as well so expect another Winter Storm Watch or Warning for some areas.

None of the snow from the Tuesday event will have melted, so we could see a whole bunch pile up on Thursday night and into Friday.

Christmas Eve and Christmas Melt!?

The arrival of that Pacific system on Thursday should start to weaken the Arctic airmass so to top off the week, Christmas Eve and Christmas Day are going to feature two more storms!

The first lands early Christmas Eve morning and will continue the entire day and into the evening.

Will this be rain or snow? The UWash Model right now says both Saturday and Sunday will be rain events only but it’s very hard to say right now how strong the Arctic airmass is. These predictions will probably fluctuate. We could also have the local effect in Port Alberni and Lake Cowichan of the cold air sticking around in the Valleys and causing very heavy wet snow.

I would *not* plan on Travelling Christmas Eve or Christmas.

Christmas Day, pictured around noon below, brings the 4th event of the week and looks to be warm and wet. If there was a mix on Saturday, the Sunday event looks like it will finish the job of switching to rain. The only question will be whether it washes all the snow away or not!

When to travel this week?

If you need to go places this week I would suggest travelling:

  • Monday (Today, before nightfall)
  • Wednesday
  • Thursday *morning
  • Friday afternoon
  • Stay where you are Saturday and Sunday!

About The Author