>Winter 2009-2010 “feels” like it’s already arrived across much of Canada as record breaking cold has struck western and central regions and the swath of early season snow and cold is sweeping east bringing a blanket of white across Ontario and Quebec which in turn allows for increasingly cooler nights with the snows radiative heat-loss effect back to space at night, is the current wintery pattern a sign of things to come?

A weakening El Nino into the December-January time frame will likely play a role in Canada’s upcoming winter. The country vast size creates a tough forecast as this country can experience such wide variety of weather.

Weak El Nino’s often (but not always) can lead to a ridge-trough situation or meridional jet pattern in winter and I expect for the core of the winter months (late December through January 2010) to see a CLASSIC “WEAK EL NINO” PATTERN set up that presents more mild and dry to the western side of the country, say from Vancouver to the western Prairies whilst colder, snowier weather takes charge further east but this doesn’t mean either colder/snowier and milder/drier can’t hit in other areas.

DYNAMICS IN PLACE

1. A Cooler North Atlantic compared to recent years with cold water over top of warmer, with the band of colder water which formed last winter off New England and expanded throughout the summer months stretches from Newfoundland to the Irish/Scottish coast which COULD enhance the liklihood for a North Atlantic blocking pattern which would lead to colder air penetrating into eastern Canada.

2. A colder Pacific Decadal Oscillation and the type of summer & fall season we have seen across Canada with very cold March-early June across Canada which is part of a long term multiyear pattern which formed I believe in the winter of 2007-08 brings me to the conclusions I share in this forecast.

3. Faster growth of Arctic Sea Ice could allow Arctic air to charge faster than what we have seen over the last 8 to 10 winter seasons and with increasingly cooler summers across the country despite the warmth over the West this past summer could be reasoning to believe the Cold PDO is reducting temperature across the hemisphere and therefore colder air is growing and growing stronger. Fall was extremely cold and with lack of ice melt of Hudson Bay, summer in Eastern Canada was very chilly up until late July and then finally we saw warmth, this perhaps was when Hudson Bay melted it’s ice and the body of water itself warmed enough to cut off the chilling feedback and encouragment of the eastern trough. This very cold pool also encouraged the intensification of the western ridge, therefore explaining the possible reasoning behind the extreme heat in unusual places such as Seattle and across Western Canada and all the way to the Arctic where it managed to top 81 degrees.

VANCOUVER WINTER GAMES: Confliction of Thought
Early start to winter is great but sharply turns at the close of 2009, much of winter to be dry in west and across most of Canada with wetter than normal over the far east of the country (Maritimes) which could be hit by several major coastal storms.

BRITISH COLUMBIA, ALBERTA AND SASKATCHEWAN
EARLY WINTER BLAST OF SNOW AND FOLLOWED BY FRIGID COLD
Western Canada should expect a mostly drier than normal winter overall with a southern branch jet swinging into the central California coast and this should mean less snow to places that have seen recent bumper snow years like in the British Columbia Rockies. However, I am expecting a blast of Arctic air in the early (between late November and Christmas) part of the 2009-10 season with heavy coastal snows and major or even record snowfalls in the Mtns around Vancouver as some strong Pacific lows spin off the Pacific as the pattern and atmosphere adjusts to the change of the season. I do expect what may appear to be a sign of yet another great snow year ahead with a series of storms that blanket the mountains but only to see this pattern become replaced by higher pressure and a storm track that heads south. The heart of winter may see a western ridge form with an undercutting low pressure belt under the warm pool that develops from east of Hawaii to the Great Basin and north into Alaska.

The “positive Arctic Oscillation”, which is the intensifier of cold air over the pole, will allow rebuilding of harsh Arctic air over the pole as the now negative oscillation which is spilling all this cold air south at the moment (mid Oct) will pull this north as the AO returns to it’s positive state as pressures rise across much of the continent and warms it up. Another swing to negative in the AO will occur perhaps in late November and through December and the Arctic air will drive into the west and then progress east throughout December.

I believe that the storm track will shift south as the reservoir of Arctic air matures and grows as New Year approaches, it may be cold to very cold but the snowfall won’t be part of the pattern from Oregon, northward after mid to late December.

I do expect a few substantial snowstorms for the Rockies and one or two low level snowfalls for Victoria to the Vancouver metro. Calgary, Edmonton, Saskatoon, Regina will see their snowpack build fast early on but then sut down at the close of 2009 only to be replaces by firstly cold Arctic high pressure that could bring record cold from Vancounver to Winnipeg and then a warmer high from the south may build up the western flank, presenting a situation where the warmth pushes north into Alaska, but therefore dislodging the most severe cold over the pole southward towards the central and eastern portion of Canada at the same time central and southern West Coast areas get hit by rain, snow and wind.
Major cold will cripple the heart of North America between December 15 through January 15 with the major precipitation crossing the southern flank of the continent, a few pesky Alberta clippers may form a series of coatings from Yellowknife to Winnipeg and will form a series of cold pockets that reinforce the chill that will dominate the heart of North America. As the mid-January period arrives, the core of Arctic air will push towards the eastern half bringing extreme cold from the Great Lakes to Eastern Seaboard where New York City down to Washington will drop below zero and experience wind chills between 25 to 35 below zero.

EASTERN CANADA TO EXPERIENCE COLDEST TEMPS IN POSSIBLY 20 TO 30 YEARS
From Winnipeg to Quebec City, a monster Arctic high that forms over the heart of Arctic Canada through November and December will progress southeast with impulses of the main vortex crossing the country behind a series of Alberta clippers and around early to late January the core of this Arctic high will sit over Hudson Bay and fall into southern Ontario and Quebec where snow cover is widespread as far south as Virginia and Maryland, allowing this air mass to impact with full force. Montreal, Ottawa, Quebec City and Moncton will endure savage cold and wind chills.

Coldest possible highs and lows.

Montreal, 0F/-18C high, -35F/-37C degree low.

Quebec City, -5F/-21F degree high, -40F/-40C degree low

Thanks for reading.

-Mark

Feel free to share your thoughts, ideas and even comments about my forecast either in the comments link below this or by email at [email protected].