Ag Weather Forum

Very cold weather continues to be the rule for most of the Prairies but some mild Pacific air has made inroads into southern Alberta and even southwest Saskatchewan at times during the past several days. Some of these areas have seen the weather turn mild for a few hours followed by a dump back to very cold levels as the wavering arctic boundary shifts back westward.

The scene will likely continue to be played out across the western Prairies during the coming days and probably through the remainder of the month while the eastern half of the Prairies are looking more likely to stay locked in a cold or very cold weather pattern.

A slight nudge to the west of the persistent trough across eastern Canada during the next week will allow for some westward expansion of arctic air, but this is probably not a permanent change as most models indicate that enough ridge remains near Canada's West Coast to allow for brief interruptions in the cold for parts of Alberta and maybe southwest Saskatchewan.

These areas of Western Canada are known for dramatic temperature changes over short periods of time and the time of year that these changes are more likely is during the late winter and early to mid-Spring. Chinook winds bringing mild weather from the west can quickly weaken allowing arctic air to surge back up against the Rockies and send temperatures plummeting by 30 or 40 degrees Fahrenheit in just a few hours.

The overall weather pattern across North America remains in a rut. A strong upper ridge across the north-central Atlantic is blocking any eastward translation of the eastern North America trough, thus keeping a second ridge in place near the west coast of North America. Last year we saw unending high latitude blocking which create cold air across North America. This winter it is mid-latitude blocking creating nearly the same pattern, but translated eastward about 1000 miles from last year.

The pattern we have gotten into is a little more productive in the snow department across Western Canada and we may see a few more clippers ride through the region during the coming week depositing light amounts for the most part. Over time the several light snow events do start to add up on the ground.

Early indications for March show the theme of February continuing, but with maybe some weakening of the trough across the eastern half of Canada. Some weakening of the trough might allow Chinook winds to become a little more widespread across at least the western Prairies at times.

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

(ES)

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