Ag Weather Forum

Rains Affect Prairies Harvest

Doug Webster
By  Doug Webster , DTN Senior Ag Meteorologist

After a very dry start to the growing season for many Western Canada areas, the rains have come during the past month and allowed soil moisture levels to improve substantially.

Unfortunately, the rains were late for some of the earlier maturing crops and lowered crops yields are likely for these crops. Late maturing crops are likely to fare better with the mid-summer rains allowing for better yields.

Harvest operations continue to build across Western Canada and the focus is shifting from the need for rain to the need for good weather conditions for swathing and combining crops. A couple of recent storm systems brought rain and wind, which lodged and flooded crops, as well as delayed harvest.

Mother Nature is about to throw another early fall type storm system at us Friday and Saturday as low pressure tracks along the U.S./Canadian border region. Moderate to locally heavy rains will likely fall for much of the region and the rain combined with some strong and gusty winds may produce more lodging of crops as well as some flooding.

I used the term "fall type" for the upcoming storm for two reasons: One being the rain and wind pattern associated, but also because of the expected low temperatures to accompany and follow to storm. There may be a few places by early Saturday across Alberta that see some light frost and the same pattern may occur early Sunday for parts of central Saskatchewan.

We are not expecting temperatures to be cold enough to produce any significant damage however. Some spots through northwest Alberta saw some isolated frost early this week, but it is unlikely that any damage occurred.

The cool weather is a result of what has become a very active and early fall looking weather pattern across Canada. The jet stream has strengthened and shifted to far southern areas of the nation and allowed a series of low pressure areas to provide rainfall, as well as bursts of cool air from northwest Canada.

We are moving into the last third of August and cooler weather is to be expected. Given the type of weather pattern currently in place, we might be fearful of an early frost or freeze, but there are signs that the pattern may relax for a time next week and possibly into very early September. This would be good news to prevent early frost and also for the increasing harvest work.

Much warmer, drier weather for next week will help those in full swing harvest mode, as well as late-maturing crops. There are indications that once we get a little bit into September that temperatures may swing back to the chilly side of normal and that could increase frost and freeze threats.

Normal first frost dates will be fast approaching in just two to three weeks for many parts of the Prairies and a cooler-than-normal weather pattern might bring the frost on sooner. This is something to keep an eye on, but for now it appears we should see a good week of harvest weather next week after a bump in the road Friday and Saturday.

Doug Webster can be reached at



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