Ag Weather Forum

Windy Storm Pattern Affects Prairies

Joel Burgio
By  Joel Burgio , DTN Senior Ag Meteorologist
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A strong pressure gradient between high pressure over Western Canada and a deep surface low in the Great Lakes led to harsh winds across the Canadian Prairies during the past week. (NOAA map by Nick Scalise)

Storms moving across the Canadian Prairies region have recently caused high winds, damage to property and localized crop damage as they moved across. As earlier reported, Oct. 17's storm was especially severe as it moved rapidly across the region, but another windstorm is currently occurring over the eastern part of the area. This is not as severe as the one last week. Today's storm also includes snow, which means blowing snow when combined with the strong winds.

These storms have their origins in a mean upper level trough that as of last evening was situated over the Aleutian island chain of Alaska. The surface storms dampen out as they track over an east Pacific Ridge. However, they then intensify again as they come down hill on the east side of the ridge, especially as they near the mean trough that is currently located in central Canada.

The jet stream between the east Pacific ridge and the Aleutian low is fairly strong at this time which contributes to the fast movement of these storms tracking through the northern Pacific and into northwest Canada. We also note tropical lows moving out of the western Pacific are likely a contributing factor in these impulses as they move across the northern Pacific towards the Aleutian low.

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As we look to the forecast, we see yet another surface low and upper level impulse moving over the top of the east Pacific ridge and into northwest Canada this coming weekend. The ridge in the Pacific and the trough in Canada appear to be a little east of where they are currently located at that time.

This might mean the intensification of this new storm would take place after the low moves east of Manitoba early next week. If this verifies, then the storm and the high winds would affect Ontario, and possibly Quebec, more than Manitoba.

The longer-range charts, covering the eight-to-10 day period, Nov. 2-4, indicate a westward shift to the pattern. The Aleutian trough looks to be replaced by a strong upper level ridge. This causes the Canada trough to shift west as well. The first implication of this shift would be to again alter the storm track to allow another strong wind and snow event to threaten the Manitoba area and vicinity.

A second consequence of this shift in the pattern is the build-up of a strong surface high in Alaska and northwest Canada that will follow this storm southward into the Canadian Prairies region. The contrast between the high and low pressure centers might add to the gradient and increase the wind threat with this new system.

Another possibility, looking at the long range, is that the stronger surface highs might cause the storm track to shift south of the Prairies region beyond the 10-day forecast period. This could mean less of a risk of strong winds and stormy weather. However, even if this does occur, it wouldn't be until after at least two more wind storm threats, beyond today's system.

The bottom line here is that the pattern of windstorms affecting the Canadian Prairies looks to continue for another week to 10 days, but there is some chance that this would change beyond the 10-day period. The new pattern, if realized, would mean more and larger surface highs and less stormy weather.

Joel Burgio can be reached at joel.burgio@dtn.com

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