Ag Weather Forum

Winter is set to come to a close in less than a week, but what the calendar says and what nature does are two different things most of the time.

A weather pattern featuring lots of high latitude blocking across northern Canada to Greenland will deflect the jet stream southward to locations further south than normal for mid and late March.

The idea of blocking across northern Canada and Greenland can be analogous to a flowing stream where a large rock is located in the middle and the water is forced to go around the rock. The high pressure ridge in the upper atmosphere across northern Canada is like the rock and forces the jet stream flow to flow further south and around the ridge.

The more southerly position of the jet stream creates a weather pattern more in tune with mid-winter weather patterns across Canada sending arctic air further south than normal. We expect more very cold weather during the next two weeks across the croplands of the Prairies and we are also expecting more snow, possibly some heavy snow totals for some areas.

The increased snow on a snow cover that is already inflated, combined with the cold weather, will delay the beginning of any spring meltdown and also further increases the flood potential when the meltdown does eventually begin. Current computer model forecasts show several low pressure systems coming along that will be capable of producing moderate and some locally heavy snows across areas from Alberta to southern Manitoba during the next two weeks.

Arctic high pressure across northwest Canada will allow for an upslope wind to help enhance snowfall along the east slopes of the Rockies which could produce the heaviest snows through Alberta and western Saskatchewan. Low pressure areas are expected to track across southern British Columbia to Montana before heading into the Dakotas. This is a track that can bring sizable snows to the Prairies.

The first of these storms is expected to arrive tonight and last through Friday night with lingering light snows Saturday. A second surge of snow should envelop the region during Sunday. Potential snowfall of 10 to 25 cm is expected for crop areas of Alberta and Saskatchewan, with higher totals possible in scattered locations between tonight and Sunday. Snow totals are expected to be less across southern Manitoba where cold air will be deeper and tend to force the moisture to pass by to the south.

Further storm activity during the middle and end of next week may combine with continued cold weather to bring more snow to the region.

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

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