Prairie Weather (Rural Roots Canada) – Milder weather this week replaces the snow and cold. For a while.
There is relief on the way for most of the prairies following the cold and snowy conditions that disrupted prairie life last week. The maps below show anomalies in temperature and precipitation. On the left, the map indicates for this week, temperatures in most of Alberta are expected to be warmer than average. In Manitoba – cooler than average. The precipitation map shows an area of green over central and northern Saskatchewan, where above normal precipitation is expected. Elsewhere, the prairies show white, which doesn’t mean dry. It simply means expected precipitation will be near the long term average. Because January is, on average, a low-precipitation month, we expect some snow, but not a lot.
Courtesy: ECCC
In fact, if we take an even closer look at expected snowfall this week across the prairies, the numbers are very low – less than 2.5 mm water equivalent in most of Alberta, and less than 10 mm elsewhere.
We can conclude not much new snow will be added to the pack across the prairies this week. What is less certain is how much will disappear when Alberta warms up. Some will disappear, for sure. But not much. While temperatures will climb above zero, they will do so by only a few degrees. An air temperature between 0 and +5 isn’t going to make snow disappear, because the snow temperature is still 0 or below. If it’s cloudy, there won’t be much impact on snow depth. On the other hand, if the sun comes out, it’s a different story. The chinook wind will warm the air, and the sun will heat the snow. That will cause it to evaporate or melt. So, how much snow we lose this week will be more a function of the hours of sunshine, rather than the warm, downslope chinook wind.
All across the prairies this week, there will be a warming trend. And as temperatures rise, so will the speed of the wind.
Monday
Alberta
Arctic high pressure that maintained cold weather across the prairies last week will continue to affect the region early this week. In Alberta, the extreme north can expect extreme cold in the eraly morninng. Later in the day, changes begin. The day’s likely to start with light snow or flurries in parts of central Alberta, and fog in southern Alberta. Around midday, the flurries and fog fizzle and the sky begins to clear. Mild Pacific air heads toward Alberta from the west, and arrives in the afternoon. After a very cold start to the day, areas west of highway 2 should see temperatures rise to zero or higher. East of highway 2, it is likely to remain colder than the melting point all day.
Saskatchewan
The Arctic high moves south from the Territories to central Saskatchewan, dragging the cold air with it. Extreme cold can again be expected early in the morning in northern Saskatchewan. Afternoon temperatures across Saskatchewan will be well below average, with highs remaining in the -20s. The Arctic high will keep the province dry, except perhaps for far northern regions.
Manitoba
Extreme cold is likely to persist through the day in northern Manitoba. In central and southern regions, temperatures will remain in the -20s all day, with the Arctic high pressure system continuing to block any warmer air. Some weak disturbances in the circulation around the high could bring flurries or light snow to southern Manitoba during the day. Amounts will be minimal. Agricultural areas in southern Manitoba will be under cloud cover through the day.
Tuesday
Alberta
High pressure develops in the East Kootenay region of British Columbia, pushing mild Pacific air from BC into southern Alberta. A chinook wind develops, and temperatures across the province will rise above the long term average. Highs across most of Alberta will be within a few degrees of zero, with the warmest region being the area north of Jasper to Grande Prairie. Temperatures there could climb to the high single digits, though it will be cooler in the lower lying valleys. With the drying effect of the chinook wind, no precipitation is expected anywhere in Alberta on Monday.
Saskatchewan
Mild Pacific air that has warmed Alberta will begin to invade Saskatchewan as the arctic High pressure system that has perhaps overstayed its welcome begins to weaken and move on. The western half of Saskatchewan will warm to about -10, while -20s persist along the Manitoba boundary. Most of Saskatchewan will have a snow free, mainly sunny day.
Manitoba
It’ll be another day of bitterly cold weather, with parts of western Manitoba awakening to -30 degree temperatures. Morning lows elsewhere will be in the mid -20s. There won’t be much recovery during the day, as highs will remain near -20. The Arctic high that has produced the cold, dry weather will weaken, and there will be some improvement in temperatures as soon as Wednesday. Other than a few early day flurries near Lynn Lake, no precipitation is expected in the province Tuesday.
Wednesday
This is a truly remarkable temperature map for mid-afternoon Wednesday:
The red and yellow colors show temperatures above zero. This shows an incredibly large chinook along the eastern slopes of the Rocky Mountains from northwestern Alberta all the way to the Texas Panhandle. A westerly downslope wind will boost temperatures into positive levels. However, it will be perceived differently depending on region. In Alberta, the positive temperatures are warmer than average. In Texas, it will be seen as a cool day, as daily average highs at this time of year are well above the +1 to +5 degrees forecasted.
Alberta
The map above shows afternoon temperatures across Alberta will climb to 0 or above, with a few spots in the foothills reaching the mid to high single digits. The strongest westerly wind will be aloft, but it will be rather brisk at the surface as well. Some of the computer models show rain from Calgary to Claresholm in the afternoon. This is highly doubtful. And if it does try to rain, the moisture would likely evaporate before reaching the ground.
Saskatchewan
Again, referring to the map above, the western 2/3rds of Saskatchewan will be rather warm with temperatures exceeding the melting point. For reasons stated above, don’t expect too much snow to disappear in the warm air, as the sky will be mainly cloudy, and the air temperature won’t be warm enough to cause any serious melting or evaporation. There is a chance of a mix of rain and snow in central Saskatchewan during the midday, but there is considerable uncertainty. However, later in the day, with a shift in the wind to the northwest, an area of snow may develop in southwestern Saskatchewan right around sunset.
Manitoba
While the warmest Pacific air stays to the west, Manitoba will warm up somewhat. Instead of highs in the minus 20s, temperatures should rise to the minus teens. Snow can be expected over Lake Winnipegosis, and the northern basin of Lake Winnipeg, extending north toward Churchill. Southern Manitoba will remain dry, but mostly cloudy.
Thursday
Alberta
Chinook conditions remain in southern Alberta on Thursday, but the system does break down in northwestern Alberta, where snow will develop in the midday, as an upper level low pushes into the region. 5-8 cm are possible around High Level, and possibly as far east as fort McMurray. A low develops in northeastern BC, with a warm front toward Grande Prairie. Freezing rain could develop near Grande Prairie into the night, and may extend as far south as Red Deer by noon Friday. The rest of the province stays dry, with highs above zero along the foothills and in most areas west of highway 2. Expect strong wind Thursday night in southwestern Alberta. In eastern Alberta, high temperatures will likely range between 0 and -10.
Saskatchewan
Wednesday’s warm air will not carry over into Thursday, and highs in Saskatchewan will step back to the -5 to -15 range. Along with a northwest wind, snow is expected in the midday in eastern Saskatchewan, along the Manitoba boundary from Reindeer Lake all the way south to North Dakota.
Manitoba
Manitoba will have a rather mild day, with highs across the southern half of the province reaching -5 to -10. However, the warm air will be accompanied by snow, which will fall across the south for most of the day into the mid-evening. Snowfall intensity should be light to moderate, but there could be significant accumulations as the snow will continue to fall for several hours.
Friday
Alberta
Alberta will begin to transition out of the chinook, with a wind shift from the west to the northwest, and a cold front passing from north to south in the afternoon. There may be some snow and/or rain accompanying the front as it passes. Around noon, the front should be near Red Deer, and by evening, it’s south of Calgary. The front is attached to a Low in southern Saskatchewan. Because of wind, temperature, and precipitation conditions, freezing rain can’t be ruled out near the Saskatchewan boundary, and those with travel plans in southern Alberta during the day on Friday should be aware of weather forecasts and potential hazards. Before the frontal passage, temperatures in southern Alberta during the morning and midday will likely be in the high single digits, perhaps close to ten degrees. After the front passes, temperatures will drop below the freezing point in the early evening.
Saskatchewan
During the day, mild westerly wind will provide above freezing temperatures to western Saskatchewan. It is likely to be the last day for mild weather in Saskatchewan, as the Alberta chinook begins to break down. This will allow colder air into the region for the weekend. A Low pressure system will develop in the afternoon in north-central Saskatchewan, and with the temperature being so close to zero, it’s hard to determine what kind of precipitation will be associated with the Low. The potential is there for mixed precipitation or freezing rain from Regina northwest to Rosetown, and with snow elsewhere across most of the province.
Manitoba
Frigid weather returns to the far north, with temperatures in the -20s and -30s, but in the south, it’ll remain relatively mild, with highs again from -5 to -10. Another dry day is expected, though moisture from a low in southern Saskatchewan will generate snow in west central Manitoba between Pukatawagan and Lynn Lake. That will develop in the afternoon.
Saturday
Alberta
Snow from a Pacific weather system coming into the province from the northwest will develop on the eastern side of Alberta. Expect light snow throughout the day east of Highway 56. The snow is falling along an inverted trough stemming from a Low on the North Dakota/South Dakota border. Despite the northwest flow, it will remain rather mild in Alberta Saturday, with highs across the province ranging from 0 to +5
Saskatchewan
An invasion of Arctic air drops temperatures to the -20s and -30s across northern Saskatchewan. In the south, it’s much warmer. Highs will be near zero in the Saskatoon area, and above zero in southwestern Saskatchewan. However, a reverse temperature trend develops in which it gets colder as the afternoon wears on. Temperatures will likely drop 3-5 degrees by late afternoon. The arctic air is coming in on a northerly wind. There will be light snow in southern Saskatchewan through much of the day.
Manitoba
A Low in the Dakotas will push snow into southern Manitoba throughout the day. There may be some significant accumulations. The snow will be light, but because it will fall over a period of several hours, there will be opportunity for a few cm of accumulation through the interlake and in southern Manitoba. As the snow falls, so will the temperature. A northerly flow of Arctic air will drop temperatures into the -20s across the province.
Sunday
Alberta
It’ll be another fairly warm weekend day in Alberta with highs near or perhaps even slightly above zero across most of the province. The warm air is coming into the province from the southeast, circulating clockwise around a high pressure system on the Saskatchewan Northwest Territories boundary. This circulation will draw in some snow from a Low that had given snowfall to Saskatchewan and Manitoba on Friday and Saturday. On Sunday, the snow will fall along the Alberta Saskatchewan boundary, and in the foothills and Rockies.
Saskatchewan
As Arctic high pressure builds through the day, snowfall in southeastern Saskatchewan gets pushed out of the province. The sky across most of the province will be clear, but it’s an arctic air mass, so it will be cold in most areas except for the southwest. Expect temperatures to fall to the -20s across most of the province. In southwestern regions, highs will come in between -5 and -10.
Manitoba
Arctic air plunges into the province, dropping temperatures to the -20s all day long across all of the province. This is very dry Arctic air, so most areas will experience sunshine. Except for the north, where a weak low near Port Nelson will provide snow as far north as Churchill.
In Other News…… La Nina is here!
The National Oceanographic and Atmospheric Administration confirmed on January 9 that La Nina has begun. You can read about it here.
On Monday’s Prairie Weather This Week, we’ll take a look at the impact of La Nina in western Canada.
COMPARE: Prairie Weather This Week – Dec 30
