Yukon Weather Update

It has been a cold and snowy weekend for the Whitehorse area this weekend, with high temperatures around -20 deg F. About 4-5 inches of snow fell, and Whitehorse Airport is reporting 13.4 inches of snow on the ground currently.

Overview:
A strong ridge of high pressure will be moving into the area this week, and temperatures may exceed freezing Thursday and Friday. This ridge of high pressure will slowly be moving east though, allowing stormy and colder weather to settle into the area during the weekend. Expect a chance of precipitation to begin on Saturday, possibly in the form of rain. Precipitation is expected to increase on Sunday, and any mixed precipitation will likely change over to all snow.

Discussion:
The map in the left panel of the figure shows the forecast weather pattern for Friday. Each individual line is the result of a different model simulation, and the yellow line in the middle is the mean. This gives an indication of the uncertainty in the weather forecast. The closer the lines are together, the more certain the weather forecast. The 2 different sets of lines (red and blue) are forecast values for 2 different pressure values. An upward "bulge" in the lines means high pressure, and downward "bulge" means lower pressure. For Friday, it is fairly certain that there will be a ridge of high pressure in place for the Whitehorse area.

However, for Sunday, a downward bulge is present just west of Whitehorse, meaning low pressure, unsettled conditions, and cooler temperatures. Notice the blue lines are not as close together though, and look more "spaghetti" like. This means there is a lot of uncertainty in the weather forecasts for Sunday still.