Frost quakes, ice storms, blizzards: What's next?
Thursday, January 9, 2014, 10:42 AM -
Frost quakes? polar vortex? It’s really something when you hear the public using these terms on a regular basis. It has been quite the winter across Canada with ice storms, blizzards, frigid temperatures and snow hurricanes -- and it doesn’t look like the active pattern will be dying down.
First, let’s get some facts straight about this “polar vortex” everyone is going on about. The polar vortex is by no means something new or something rare. It is a permanent atmospheric feature all year round existing at the North and South Poles. They are a circulation (on a planetary scale, not a mesoscale like a tornado, so it’s big) and are located from the middle troposphere to the stratosphere so it is an upper level phenomenon. The polar vortices are strongly reliant on large scale temperature gradients so in the winter, they are at their strongest due to the temperature gradient between the equatorial regions and the poles. The term “polar vortex” has been used in scientific papers since the 1940’s.
If you recall two winters ago when winter was absent from the majority of North America, this was partially (but not completely) due to the fact that the polar vortex in the North Pole region was “stuck” up there so the colder air was bottled up and not drifting into southern latitudes. Here's a brilliant explanation by Weather Network meteorologist Doug Gillham about what the polar vortex is and why we have been so cold.
Part of the reason we have been so cold is due to cross-polar flow: cold air coming straight from Siberia. But why is Siberian air colder than Canadian Arctic air? Doug explains:
NEXT PAGE: WILL THE WEATHER ROLLER COASTER CONTINUE?
The roller coaster continues as it did in December and the beginning of January. The next two weeks will bring, once again, an up and down temperature trend. The end of December and beginning of January proved to contain frigid temperatures from the Canadian Prairies through to eastern Canada. The only provinces spared from the bitter cold was British Columbia and portions of southern Alberta.
Temperatures are on the rise as we get a small reprieve from the bitter, winter cold. Warmer air will flood its way north from the Gulf of Mexico leaving Ontario, Quebec and Atlantic Canada above normal through the weekend and early next week. Mild Pacific air will keep the southern Prairies slightly above normal as well.
This is but a small respite as cold air will make its way back in. I mean, it is January in Canada, right?
Below shows the cold temperatures return at the end of next week with well below normal temperatures moving back in to the previously affected areas and the west coast temperatures on the rise. A large ridge in the jet stream is being hinted at by several long range models leading to the warm up on the western coast and Alberta. A large trough will move over eastern Canada opening up the cold flood gates once again.
READ MORE: WHAT DOES THE FUTURE HOLD FOR EASTERN AND WESTERN CANADA?
After blizzard-like snow squalls and frigid temperatures in Ontario and Quebec, a warm up is on tap for the end of this week into the weekend. December had every major city across Canada average below normal for temperatures. Because of the cold, rainfall totals were below average but snowfall totals were near or above normal. Toronto was right on point for normal snowfall amounts and about 2°C below normal for temperatures. Montreal and Ottawa were both below normal for temperatures and snowfall totals were above normal. It was certainly a wet December in Atlantic Canada. Snowfall totals were well above normal with Charlottetown and St. John’s receiving double their normal amounts.
A low pressure system moving up from the south U.S. will bring moderate rain but also warmer temperatures. After daytime highs sitting closer to -20°C, the forecast high of 5°C on Saturday will be feeling downright tropical! Current model indications suggest 15-30 mm of rain for southern Ontario and southern Quebec and 30+ mm through Atlantic Canada. Areas north of the Nickel Belt could receive 10+ cm of snow. As discussed below in the Western Canada outlook, a series of clippers will move their way across the Prairies and into eastern Canada so small rounds of snow are not out of the question next week but temperatures won’t begin to drop until later next week. By the end of next week and next weekend, temperatures will be chilly once again.
Cool and dry is a good way to describe southern British Columbia’s December and beginning of January. Victoria and Vancouver both averaged below normal for temperatures and below normal for precipitation (rain and snow combined). Rain was way below average with Vancouver International receiving about 45% of its monthly average rainfall for December and Victoria receiving about 30% of its December average rainfall. Snowfall was close to average with Victoria receiving about 13 cm and Vancouver receiving 12 cm (the majority of which was from one storm system).
Cold and snowy would be an appropriate way to describe Alberta’s weather in December with temperatures averaging 3°C below normal and snowfall amounts about triple the climatological norm for December. Saskatchewan and Manitoba weren’t particularly snowy in December but temperatures, once again, averaged well below normal.
The next couple of weeks offer a variety of weather for western Canada with a stormier pattern returning to the west coast now through the weekend. A more zonal (or flat) pattern in the jet stream will help steer low pressure systems into the B.C. coast right through to mid-next week with rain (or snow in interior British Columbia) almost every day until the end of next week.
NEXT PAGE: WHAT ABOUT THE LONG RANGE?
These low pressure systems will then impact the Prairie provinces as the energy from the system transfers over the Rocky Mountains and spills across the Prairies. The mild, Pacific air and flow will keep temperatures on their typical roller coaster ride in Alberta, especially the south, with daytime highs sitting above freezing for the next week. A generally westerly flow across the Rockies will aid in some Chinook winds to keep southern Alberta’s temperatures warm. Some of that mild, Pacific air will even make its way into Saskatchewan and Manitoba leaving their temperatures at or just below freezing unlike the -30’s experienced in the last little while.
The warmer pattern doesn’t necessarily mean calm weather. We do expect storm systems to continue their trek across western Canada as the lows make their way on shore over the next week. We will see some clippers break off the Rocky Mountains in Alberta and drop some light snow (or even mixed precipitation) and gusty winds as they journey eastward.
In the even longer range, forecast models are indicating another blast of cold Arctic air to flood over the Prairies; this is two weeks out or after the weekend of January 18th. So over all, a wetter, warmer trend for British Columbia this week followed by a cool down the week after. A warmer trend for the Canadian Prairies this coming week will be followed by another ejection of cold air from the Arctic the week after.