Yukon weather report

Looks like it was a good weekend at Whitehorse. Attached is a figure summing up the weather. Red line = actual highs, Blue line = actual lows, Green line = average highs, yellow line = average lows, magenta = record highs, cyan = record lows.

A record high of 50F was broken on Sunday! The old record was 43F which occurred in 1948. Only 10 days earlier the temperatures was -40F.

No rain fell on Saturday, so January 17 is still a rainless day in Whitehorse.

Temperatures are currently still above freezing, but are expected to drop to about 18F by the end of today. It has been over 3 days since the temperature has been below freezing.

Final Yukon Weather Update

Forecast for Whitehorse, Yukon:

Friday...Increasing cloudiness. Highs in the low 40's*. Southerly winds 10-20 mph.

Friday night...Cloudy with a chance of rain showers. Lows in the upper 30's. Southerly winds 10-20 mph. Chance of rain 50 percent.

Saturday...Cloudy with rain* showers likely. High temperatures in the upper 40's*. South winds 15-20 mph, with localized areas of winds over 45 mph. Chance of rain 60 percent.

Saturday night...Rain likely. Lows around 40. South winds 15-25 mph, with localized areas of winds over 45 mph. Chance of rain 60 percent.

Sunday...Occasional rain showers, mixing with snow late. Highs in the mid *40's, with temperatures decreasing into the mid 30's. Chance of precipitation 50 percent.

Sunday night and Monday...Mostly cloudy with a mix of rain and snow showers. Temperatures decreasing into the 20's. Precipitation chances increasing late morning.

Records that may be broken:
Friday: Record high is 41.
Saturday: Precipitation has never fallen in the form of rain in Whitehorse on this day.
Saturday: Record high is 48.
Saturday: Average high is 7F. This makes the LOW temperature ~33F above average HIGH
Sunday: Record high is 43.

Discussion:
Continued model trends of warmer temperatures and a delayed return of cold air. Chances that precip will be rain and not snow are fairly high through Saturday. Sunday's temperatures are now marginally cold enough for snow, and precipitation type still rather uncertain. Downslope winds (winds forced from strong winds flowing over mountain ranges) are another concern, with the greatest chances for this on Saturday and early Sunday. Although these winds occur in very localized areas, they can be quite intense. Latest forecast model runs show a strong low pressure approaching the area by midday Monday. This shouldn't be an issue since you leave early in the morning, however something to keep mindful of, especially since forecast models just now started to forecast this.

Yukon Forecast Details

Forecast for *Whitehorse, Yukon:

Friday....Mostly sunny and warm. Increasing clouds late. Highs near 45F.

Friday night....Mostly cloudy with showers developing, probably in the form of rain. Lows in the mid 30's.

Saturday...Mostly cloudy with occasional rain showers likely, especially early. Highs around 40F. Chance of rain 60 percent.

Saturday night...Rain or snow re-developing. Possibly heavy at times. Lows around 32F. Chance of precipitation 70 percent.

Sunday...A good chance of showers, probably in the form of rain early, changing to snow late. Highs around 40F, then decreasing to near 32F by the end of the day. Chance of precipitation 50 percent.

Sunday night and Monday...Occasional snow showers. Temperatures steadily decreasing into the low 20's.

* Forecasts are for the Whitehorse Airport, Yukon, elevation 2317 ft above sea level.

Discussion:
VERY tricky forecast since temperatures will be marginally cold enough for snow during much of the forecast period. To add to that, forecast models are not agreeing on the exact timing of the precipitation bands. Therefore overall uncertainty for the forecast is high. The weather maps attached are a visual aid of the forecast surface fronts and most likely areas for precipitation.

Tuesday Whitehorse Weather Update

Nearly 4 inches of snow fell yesterday at Whitehorse with a high of about -4 deg F. However the airport is reporting a total of 13 inches on the ground today, a total curiously similar to yesterday report before the new snow fell.

Thoughts:
Forecast models are tending to hold onto the ridge of high pressure with each successive model run. This is not good news for cold weather fans. Today's figure shows a plot of upper levels winds (colors) over time across all longitudes of the globe. The red colors are south winds and the blue colors are north winds in upper levels of the atmosphere, around 5 km above the ground. The location of Whitehorse is marked by the bold black line (-135 longitude). The white area in between the reds and blues is the center of the high pressure ridge (calm winds at the center of a high pressure). Things to notice:
(1) The ridge of high pressure is showing very strong resistance to move eastward (to the right) over time and
(2) By Friday night and into Saturday, the jet stream may move closer to the area, increasing the chances of precipitation.
What you can not see as easily from the map are the temperatures. A ridge of high pressure in upper levels of the atmosphere means warm temperatures. As long as this center of the high pressure is nearby, temperatures will stay warm.

Forecast:
Warm temperatures are now likely to hang on through Saturday. Highs are looking to be 35-40 deg F Friday and Saturday. Clouds will be on the increase Friday and especially Saturday, which will also keep low temperatures warm, probably above freezing both Friday and Saturday. Therefore any precipitation on Friday or Saturday should be in the form of rain. Forecast still on track for cooler temperatures Sunday with a changeover of any precip to snow.

Fun Facts:
--- If rain falls on Saturday, this would be the first time that it has ever rained on that date in Whitehorse.
--- Low temperatures Friday and Saturday may be running 25 deg F above the average HIGH temperature
--- Record high temperatures are a good possibility

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.

Weather in the Yukon

Weather forecast models are agreeing that the cold pattern currently in the Yukon will be reversing, and that temperatures will be above average next weekend.

The map on the right shows the temperature departures from average in colors about 1.5 km above the Earth's surface. The approximate location of Whitehorse is circled in black. Red shadings mean above average temperatures can be expected while blue shadings mean below average temperatures can be expected. At ~1.5km above the ground when you arrive, temperatures will be running 10-15 degrees Celsius (18-27 degrees Fahrenheit) above average! They will not be as strong at the ground, because snow cover helps moderate temperatures, but nonetheless they will be considerably above average. Currently, there is about 9 inches of snow on the ground at Whitehorse Airport.

HOWEVER, if you notice the arrow labeled 'Storm Track', you may have already deduced that the warm weather may come with a price. Although highly uncertain at this time, forecast models are calling for precipitation to begin late on Saturday the 17th, ending early on Monday the 19th. It is possible that precipitation may fall in the form of rain initially, but it is still too early to tell.

FYI, here is the average weather for Whitehorse, Yukon:
Average low, high = -7.6, +8 deg F
Coldest, warmest ever = -62, +48 deg F
Coldest wind chill = -78 deg F
Average wind speed = 8 mph
Maximum wind gust = 62 mph
Probability that temperature will get above freezing on any given day = 15%
Probability that temperature will fall below 0 deg F on any given day = 61%
Probability that snow will be on ground on any given day = 100%
Probability of measurable snow falling on any given day = 39%
Most snow falling on any one day = 5.5 inches
Average snow depth on ground = 11 inches
Greatest snow depth ever on ground = 33.86 inches