Ag Weather Forum

Very Cold Pattern Breaks Down in W. Canada

Doug Webster
By  Doug Webster , DTN Senior Ag Meteorologist

After a milder-than-normal December, 2 to 4 degrees Celsius (4 to 7 degrees Fahrenheit) for most areas, we've seen January bring us a heavy helping of what last winter offered. The arctic air manufacturing machine got back into business as the new year began but this time around the staying power looks to be limited.

The very cold weather across Canada so far in January has mostly been produced by a strong ridge extending north just off the West Coast of North America blocking any modifying influence of the Pacific. The polar vortex has been swirling about through northern Quebec and the Hudson Bay region during the past week flinging surges of cold air south across much of Canada.

This pattern certainly can produce cold weather and temperature departures have been on the order of 10 to 16 degrees Celsius (18 to 32 degrees Fahrenheit) below normal at times across Western Canada during the past week. This pattern lacks something that was in place last winter and that's the strong high latitude blocking that kept last winters' pattern in place for months on end.

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

The pattern of early January 2015 has a high amplitude ridge and trough pattern and these types of patterns usually do not last long before de-amplification takes place. It appears this process will get underway this weekend into next week as the ridge along Canada's West Coast weakens and the polar vortex lifts to northeastern Canada. The result will be more of a west-to-east jet stream flow across southern Canada and the northern U.S. next week allows some Pacific Ocean influence and rising temperatures.

The strong arctic high pressure system centers of the past week will weaken and shift more into eastern Canada during the next several days allowing for the beginnings of some downslope winds across Western Canada. By the early and middle of next week we should see temperatures move up to normal and possibly somewhat above normal for the western Prairies.

Model projections indicate that milder-than-normal temperatures will occur more of the time than not for the next two weeks as some of the El Nino aspects of the December weather pattern return. Unlike last winter when cold weather was the nearly permanent feature, we are most likely to see more variable weather for the rest of winter. Don't be surprised to see cold weather return very late this month or during part of February, but that probably won't last too long.

Without the strong high latitude blocking like we observed last winter, expect changeable weather for the remaining winter, sometimes bitter cold, other times quite moderate.

Precipitation was lacking during December and so far during January, and neither the mild or cold part of the types of weather patterns we are seeing during the next few weeks look to produce significant precipitation. The sustained upslope precipitation-producing winds against the Rockies that we saw many times last year are likely not to be a feature of the weather during the next few weeks.

Doug Webster can be reached 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 .