Significant Lower Mainland Snow

Well, another round of significant winter weather is shaping up to move into the South Coast.

I want to break down timing and impacts, to better help you make decisions about potentially leaving work early or planning your weekend around the rounds of active weather.

Sorry, I won’t a note to your employer or school, though.

What we know.

A weak coastal low or trough will slide in from the northwest, but will pick up more than enough Pacific moisture.

But, weak doesn’t mean low impact—weaker lows tend to keep the modified arctic air in place; consequently, this low pressure system has significant snow potential. Northwest flow always increases the risk of lowland snow, and there’s a couple rounds on the way.

TIMING

Friday AM

·        No issues with morning commute for Vancouver

·        Shortwave still NW of the Lower Mainland

·        Precipitation and periods of snow developing late morning on Vancouver Island

·        Late morning 9-11am you’ll notice the cloud deck lower as snow begins aloft across the Lower Mainland and over higher elevations. Likely still dry in the Fraser Valley

timing1.png

Friday PM

  • Periods of snow spreads across the entire South Coas
  • Risk of ice pellets and rain/snow mix late afternoon at sea level, with Victoria likely to change over to rain into the late afternoon and evening.
 Canadian Model, highlighting the weak trough offshore, and showing all regions likely starting as snow, before a wintry mix and rain develops for southern Vancouver Island and areas immediately beside Georgia Strait

Canadian Model, highlighting the weak trough offshore, and showing all regions likely starting as snow, before a wintry mix and rain develops for southern Vancouver Island and areas immediately beside Georgia Strait

Now, for the fun stuff…

Friday Evening-Saturday AM

  • Heaviest snowfall rates expected across the Lower Mainland
  • Friday evening commute may be particularly impacted. If possible, leaving a couple hours earlier may help significantly
  • This burst of snow is well advertised on a wide array of computer models, giving moderate to high confidence
  • 10-15 cm across parts of the Lower Mainland, especially north of the Fraser River. I even think a couple localized amounts to 20 cm is possible for higher terrain of North and West Vancouver by Saturday AM
  • The secondary trough develops over the region giving mostly snow across the lower mainland through Saturday morning. Precipitation is expected to be lighter across Vancouver Island

Saturday PM

  • Snow expected to ease early on Saturday, with a mostly dry day expected for the region with a new wave of wintry-mix expected before Sunday morning which could once again bring locally heavy snowfall accumulations

 

Image above, the probability of seeing greater than 10 cm of snow a good threshold for a significant snow event for the Lower Mainland…

Precipitation shadow for East Vancouver Island expected to bring lower totals, with most cities on the east island generally seeing under 5 cm. Just 1-2 cm of snow is possible for Victoria, as precipitation intensity and temperatures become too marginal to support a noteworthy snow event for Victoria.