Final Update 9PM Sunday
The warm winds have come. We have gone from 0°C to 4°C in less than 30 minutes and the wind has switched to the SSW. Strong winds are reported on the East side. 50-60kph at Hornby Island.
Expect the Snowfall Warning to be lifted soon.
Drizzle is starting in some parts of town, ice pellets at Alberniweather. Totally dependent on local temperature and how hard it is precipitating. Heavier it is, more it will cool the air and turn to snow as long as we are within a degree or two of freezing.
Update 9AM Sunday
We received just a small amount of snow overnight but the main precipitiation is still yet to come. EC expects us to stay at or below freezing and for everything to fall as snow until later tonight.
It should begin to snow more heavily around noon and then pick up steam through the rest of the day and also gradually warm. Strongest precipitation will be tonight around 3AM. That should be past the point of warming and should be rain. We shall see.
Stay safe on the roads. So far, they are pretty good.
I think by that time the warm air will have overrun the island; you don't have the (dis) advantage of being on the continent— Chris Doyle (@ensembleator) December 18, 2016
Me too. We are already down to -4.2 °C here. Setting up for snow! https://t.co/dGfe8O38hy— Alberni Weather (@alberniweather) December 18, 2016
Given so far clear skies and some cooling this eve, i'm tending to prefer the cool solution https://t.co/TB02rACK5L— Chris Doyle (@ensembleator) December 18, 2016
Environment Canada has issued a snowfall warning for Port Alberni and all of Vancouver Island except Northern sections.
They forecast 10-20cm of snow but the models are very very uncertain on how the warm air will interact with the entrenched cold air. 5-10cm is expected in coastal areas.
Some models have us above zero right away over night, those are the freezing rain and rainy ones. Others have us staying cold. Those are the snowy ones.
The precip will start after midnight tonight. The short term models that are closer to present time have us warming almost right away and less snow. The longer term ones that are from 10AM today have us cooler and snowier.
I am inclined to go with the broader long term ones that has us snowier, like EC but I would also be very wary of thr possibility of freezing rain in Port Alberni. So be careful out there!
Here are all the different options:
The High Resolution and short term HRRR model has us warming to 2 °C by 7AM Sunday but produces freezing rain overnight tonight into Sunday morning.
The short term RAP is similar.
The US NAM is more on the warm and wet side but has quite a mix.
The US GFS is also on the cool side but has less precipitation actually falling so less snow overall but definitely on the cool side.