Ag Weather Forum

Arctic Cold In Canada

Doug Webster
By  Doug Webster , DTN Senior Ag Meteorologist

Winter's cold air descended upon western and central Canada a few days ago bringing back memories of last winter. A weather pattern very much the same as we saw so frequently last winter and spring is now in place across North America.

High latitude blocking appeared almost out of the blue less than a week ago and now grips the Northern Hemisphere and completely disrupted the modest El Nino pattern that had been in place during October. The polar vortex that was along the north coast of Russia during October now is across the Hudson Bay region of Canada. A ridge near Canada's West Coast blocks any warming influence from the Pacific Ocean.

This type of pattern allows arctic air to quickly form at this time of year. The nights are long and snow now covers nearly all of Canada. High pressure across the snow-covered landscape allows temperatures to plummet. This weather pattern creating cold air is well established now, but how long should we expect the siege of winter cold to last?

P[L1] D[0x0] M[300x250] OOP[F] ADUNIT[] T[]

The answer is a tough one. A year ago, a neutral El Nino Southern Oscillation (ENSO) condition prevailed and high latitude blocking was nearly endless all winter and spring allowing low temperatures to be dominant. This year, we have seen El Nino on the verge of blossoming across the Pacific; during October, many of El Nino type weather conditions developed across the U.S. and Canada. The mild, mostly dry weather across the Prairies was one of these parameters.

With El Nino potential existing this winter, but also with the renewed blocking patterns of the recent week, where we go from here is more clouded. Blocking appears to be the key for what kind of weather we may experience. The blocking of the past week has completely disrupted the once seemingly well-established El Nino like pattern across Western Canada.

Models have great difficulty in seeing the development of blocking, as well as its demise. If the blocking disappears, it's a pretty good bet that the milder-than-normal regime of an El Nino like pattern will return. The problem is we are at the mercy of the model inability to give us much notice of blocking's entrance and exit.

Our gut feeling is that this might be one of those winters when we see some rather great extremes in temperature. We do not feel blocking will be in place all of the time like last year, but when it is, it will likely be quite cold. When blocking weakens or disappears, it can turn much milder and in a hurry.

The model outlook to 16 days tells us today that blocking weakens but doesn't disappear during the late part of November. This would imply a turn to milder weather after another week or so of very cold weather. The problem is that these are the types of changes that the models have the least skill with and confidence is low on the forecast for this time period.

We may have one of those winters where we have to roll with the punches and accept that we may not have lots of notice when some substantial temperature changes take place.

Doug Webster can be reach at doug.webster@dtn.com

(ES)

P[] D[728x170] M[320x75] OOP[F] ADUNIT[] T[]
P[L2] D[728x90] M[320x50] OOP[F] ADUNIT[] T[]

Comments

To comment, please Log In or Join our Community .

GWL 61
11/13/2014 | 11:42 AM CST
I will take the cold, if it helps the grain market warm up. I see the combines are rolling in the snow covered fields again.