Here is where the latest short-term forecast will be kept, for quick access.
Generally, a short-range forecast is <5 days.
Possible warning-level Christmas Eve snow ahead
(Posted Dec 23)
Here you go, the first post during winter break. Temperatures thus far have stayed cold and will continue to do that for the rest of the week. Right now though, our eyes are on tomorrow, when a good system will come through and bring possibly warning-level amounts of snow.
We begin right now, with upper air analysis and surface analysis maps from Environment Canada:
On the left map, we can see the overall flow at 500 hPa. We still have our now multi-week triple upper-low system over Canada, with an anchoring low in Nunavut, and two digging lows over the BC coast and the Maritimes. We also have upper ridging over the Bering Sea, the Prairies, and the eastern Atlantic. The yellow line is where the polar vortex is, and the yellow L is the stratospheric low anchoring it. The most below average temperatures are along the yellow line.
On the right map, we have surface analysis. I have outlined areas of high and low pressure so you can see them better.
Now for the forecast. To begin, we will have to look at the low in the bottom left of the right image; the one around the coast. A shortwave trough is going to develop on the coast of the US from this low, and will quickly overpower it, turning into a deep system. It will continue to run up the coast, but once it hits Canada near midnight tonight it will split: A weaker trough off the southern BC coast, and a stronger one in the SE corner of BC.
This low will then get stalled as it runs into the big mass of high pressure over AB-SK-MB, but the cloud will not. Over the day tomorrow, the cloud associated with the system will continue to move northward, and the area of precipitation will turn into something like this by the evening:
By the way, ^^^that is another low running up the coast. The other trough that split off from the main one will disintegrate by midday tomorrow.
This snow that comes through will be very heavy, and will accumulate quite a blanket. As your actual forecast, expect snow to start sometime in the morning (between sunrise and noon), and end sometime in the evening. Accumulations are 10-20 cm for central Alberta (enough for a special weather statement to be issued yesterday), with the best chances at yellow snowfall warnings being situated in the Edmonton and Lloydminster areas.
One more thing, do not fret about drifting or even blowing snow. We are still going to be under the influence of the high, and the low is also far enough away that the stronger winds will not reach here.