March Madness (And, I'm not talking about Basketball)

I know, I know.

A lot of you have expressed your interest for that season spring...

But, since we've embraced the #WeAreWinter motto, we might as well have the weather conditions to go along with it...

First the snowfall summary, provided by Environment Canada:

SOG.png

 

Reports that Campbell River had over 40 cm at higher elevations and the same with Nanaimo (VIU) are truly remarkable for the end of February. 

For those of you who guessed 0 cm for the February snowfall contest at YVR, sorry but you're out of the contest!

There's always next time...

Anyway, right now I'm trying to decipher if this weekend will see a run-of-the-mill brush with modified Arctic air, or something of historic proportions that hasn't been seen in March in many, many years...

Yeah, It's possible.

What I Know (High confidence)

  • It's going to get colder this weekend (by Friday night/early Saturday)
  • As you know, a giant polar low is pretty much situated across most of Canada, or if you didn't the 500 mb height map below does the explaining
This is another round of the 'polar votex' that the media bit into in early January. Well, it's back baby. 

This is another round of the 'polar votex' that the media bit into in early January. Well, it's back baby. 

  • Upper ridge will move offshore (Approximately at 140W), which will work as a catalyst to usher in an Arctic front by the weekend, allowing the return of a chilly Arctic airmass to snake its way down the many inlets and valleys and settle around the Lower Mainland

What I Don't Know

  • Just how cold this event will be, and how much the upper level trough will dig into southwest BC ushering in the Arctic front and the associated cool, dense air
    • Models have yet to figure out a consensus on that 

The first model on this evening (NAM doesn't count), is the GFS and it's through about 100 hours of its run for the evening...

Oh boy Canada, this one is going to sting. 

Epic, Epic temperature departures from normal...That bright pink is over 20C below normal 

Epic, Epic temperature departures from normal...That bright pink is over 20C below normal 

EDIT: GFS through hour 90 is very epic in terms of cold for southern BC. It can't really get any better than this, if you're a cold fan.

Or...This is quickly turning into your worst nightmare:

Highlighted in Green is a giant blob of 522 heights, which will roughly represent the coldest air

Highlighted in Green is a giant blob of 522 heights, which will roughly represent the coldest air

Now, I'm about to impress you because I have a hunch, and you'll be very thankful that the Rocky Mountains are one of our natural barriers that prevent us from seeing the bone-chilling temperatures from Alberta. 

Predicted Surface Temperatures by GFS on Saturday Morning:

If you look carefully enough, it becomes obvious the Rocky Mountains are holding back the worst of the cold, and only allowing the (modified) Arctic air to seep into BC. Yeah, there's a couple -50F showing up in Alberta. 

If you look carefully enough, it becomes obvious the Rocky Mountains are holding back the worst of the cold, and only allowing the (modified) Arctic air to seep into BC. Yeah, there's a couple -50F showing up in Alberta. 

It's too early to talk about snow potential, and lets be honest, we've just been through a significant snow event for the end of February. 

Right now, it looks like the cold outflow may initiate some cyclogenesis off Vancouver Island this weekend, and swing a weak low into either Washington State or southern Oregon, but sadly that's pure speculation at this point. 

Ensembles (The responsible way)

Sorry for the very crude arrow (I know you don't come here for the graphics), but it's just illustrating how much uncertainty lies in the GFS solution right now. Ensemble members range fro -22 to -7 for 850 heights on the 18Z ensembles. Still Waiting on the 00Z

Sorry for the very crude arrow (I know you don't come here for the graphics), but it's just illustrating how much uncertainty lies in the GFS solution right now. Ensemble members range fro -22 to -7 for 850 heights on the 18Z ensembles. Still Waiting on the 00Z

For an extra layer of protection and ensembles, I'll refer back to NAEFS (although the current run won't be out until after 1030pm)

Ensemble control line for GFS in green is a huge outlier compared to the CDN and GFS ensemble members, of which most fall within the yellow thick bars.  

Ensemble control line for GFS in green is a huge outlier compared to the CDN and GFS ensemble members, of which most fall within the yellow thick bars.  

In closing, where is this cold air coming from for the weekend?

Answer: Straight from the Canadian Arctic. Below is the latest GFS trajectory model results, with most members heading into the Pacific Northwest:

Starting elevation is 5000m Above Ground Level in the middle of the Northwest Territories, with most members meandering themselves down into southern BC for early March. This model begins on February 28th 1200UTC and runs for 72 hours. 

Starting elevation is 5000m Above Ground Level in the middle of the Northwest Territories, with most members meandering themselves down into southern BC for early March. This model begins on February 28th 1200UTC and runs for 72 hours. 

#50ShadesofVan