Winter is not the time of year that soil moisture is normally built up for the Canadian Prairies. The ground is frozen, and snow cover is mostly what was left prior to the fall freeze-up. Varying amounts of rain and snow fell last fall across the Prairies with southern Alberta, northern Saskatchewan and most of Manitoba falling into the above normal category while drier than normal conditions prevailed for northern Alberta and southern Saskatchewan.
Winter precipitation is normally not very hefty and generally falls in the form of snow for most of the region and by the time spring temperatures are high enough to melt the snow a good portion of it can run off into streams and rivers over the still frozen ground. Soil moisture does reap some benefit from the melting snow if the meltdown is slow. The best-case scenario is to see a return of showers or rain when the ground is nearly or completely thawed.
Snow depths across the Prairies are not all that impressive as January comes to a close, mostly due to below normal precipitation amounts during the past several weeks. Precipitation averaged only from 50 to 70% of normal across most of the Prairies during January with northern Alberta closer to 100% of normal. Keep in mind that normal precipitation is not all that much to begin with.
The main reason for drier weather this winter has been a pretty stagnant weather pattern with a general upper level ridge across far western Canada allowing very cold arctic air, which is dry, to spend quite a bit of time across the Prairies. There have been a few weak low pressure areas move quickly through the region dropping a little light snow sparked mostly from the strong temperature contrast from east to west.
Much colder temperatures have dominated the eastern Prairies, while mild weather has made inroads across Alberta and southern Saskatchewan at times. In the short term, we do not see any major change to this pattern as we change the calendar to February. Some subtle signs point to a little less cold weather pattern during the next few weeks which may decrease the temperature contrast and lower precipitation potential. Chinook winds may become a little more common as we move into February.
Most of the climate model outlooks for February tend to favor drier-than-normal conditions for the central and western Prairies but with a better chance of precipitation for Manitoba. To accomplish this, we would need to send some stormy weather across the northern U.S. Rockies to southwest Ontario. Current shorter range forecasts are not latching onto this idea.
The current consensus is for less-than-average precipitation during the next few weeks. Whether we see an upswing in precipitation when spring begins to arrive later on remains uncertain. Some of the longer-range climate models are hinting that spring may start on a mild, dry note for the Canadian Prairies.
Doug Webster can be reached at email@example.com
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