Will It Snow This Weekend?

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This might be a little bit unnerving for some people.

How can you trust my judgement on my last post about the Vancouver Island ski resorts reopening if I can't predict if it's going to snow in Vancouver in 3-4 days...

Where's the credibility?

A main tool forecasters use in their arsenal is numerical weather prediction models, that predict that state of the atmosphere at some future time. 

There's a lack of observational data in the Pacific Ocean, so forecasters on the West Coast are at a serious disadvantage when it comes to approaching frontal systems, since most of the time the jet stream flows from west to east bringing us system after system from the data sparse Pacific.  

To visualize uncertainty in weather forecasting a bit better here's a beautiful visualization by the people at the NWS Office in Louisiana:

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Environment Canada uses this method as well when issuing their warnings, and with warning criteria weather conditions, you want a very high forecast confidence paired with low uncertainty.

Otherwise, the public would quickly lose confidence.

I have high confidence the mountains will receive copious amounts of snow (50- 100 cm) the next 14 days:

Seriously.

The latest ensemble maps for 500 mb heights support lots of Pacific Storms with a troughing pattern in lieu of our pesky ridging that has plagued the region for several months. 

But now onto gossip...

Snowstorm this weekend for YVR?

I'm in no position as of right now to call a widespread snow event for Vancouver this weekend. 

Q: Why? 

A: Model disagreement

Although none of the major models are showing a significant snow event for Vancouver on Saturday or Sunday, there's large uncertainty, but as of now Vancouver and Victoria are on the fringe for the risk of flurries. That's it.

Play spot the model differences below.

Wait... what a brilliant idea. I'll create a 'fun' book for budding meteorologists with pages after pages of model differences encouraging children to spot the many nuances of model predictions several days into the future... Any takers?

SREF Saturday 18Z

SREF Saturday 18Z

GEM Sunday 00Z

GEM Sunday 00Z

GFS Sunday 00Z

GFS Sunday 00Z

NAM Sunday 00Z

NAM Sunday 00Z

But I digress.

Right now, the majority of precipitation is shown to move under the high pressure system in BC and move south of the province, but even a 100-200 km difference brings a different situation so this bears watching and chance of flurries must be left in the forecast, especially for now! It would be irresponsible otherwise.

A more organized frontal system seems likely for later Sunday and Monday so a messy transition to the usual westerly flow is possibly in the works late in the weekend and early Monday morning.

Kids, there's a chance of a snow day on Monday, but I'll have a better idea on Thursday or Friday. Higher chances north towards locations not prone to southeast winds. Elevation will help in this case too and being away from the warm snow-eater, the Georgia Strait

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Another tool is to look at possible analogs, or similar weather patterns in the past. This is a little unorthodox, but at this point I'm going to be using it to see if it will paint a picture of what could happen with a similar atmospheric setup.

Anything will help at this point. 

The current atmospheric pattern has a high correlation (close to .9 with certain parameters) to the cold snap in early January 1998. Below are January 12th weather maps... Feast your eyes:

Current pattern has a high correlation to this map in early January 1998

Current pattern has a high correlation to this map in early January 1998

Snowfall amounts out of the 1998 transition event: 

  • Campbell River: 17 cm
  • Comox: 12 cm
  • Port Alberni: 13 cm
  • Victoria: 15 cm
  • Vancouver: 8.5 cm

Another event I want to discuss took place about a decade ago, and because the cold snap back in 2004 is of similar intensity and calibre to the current February one its worth talking about.

I was much older and remember the day vividly, as my interest in weather and meteorology was beginning to flourish.

January 6th 2004

I caught the school bus like most other days. A light dusting of snow had fallen on the ground in the morning.

I was giddy.

The streets were snow covered and my shoes made tracks in the pristine snow that was falling under the faint yellow glow of the street lights.

Heaven.

According to my recollection, Environment Canada had issued a snowfall warning the night before, but the superintendent of school district ignored the warning and school wasn't cancelled. I knew this wasn't going to end well...

Surface map at 4 am Wednesday January 7th 2004. A strong Pacific low pressure system colliding with a deep Arctic airmass. 

Surface map at 4 am Wednesday January 7th 2004. A strong Pacific low pressure system colliding with a deep Arctic airmass. 

By noon 15 cm of snow had fallen, and an early dismissal was imminent. Officials were scrambling. Mayhem. 

With the current level of forecasting ability and increases in forecast confidence over the past 10 years, schools can now be proactively cancelled, with less fear of a big forecast bust.

Administration can put faith into forecasts and meteorologists in this day and age. 

I want to thank my kind neighbour who drove me home in the 4 X 4 in the afternoon of January 6th 2004. You know who you are.

Still very much appreciated over a decade later.

Total Snowfall from January 6th-7th 2004 transition event:

  • Campbell River: 20 cm+
  • Comox: 20 cm+
  • Victoria: 15 cm
  • Vancouver: 6 cm

We'll see what this weekend brings.

Do you have a favourite snow event the past couple of decades? Any memories you'd like to share from 1998, 2004, or 2008? Comment below. 

#50shadesofVan