Moisture Updates - September 20, 2023

Synopsis

Maps 1 & 2: In the 14-days since the last report on September 6, 2023, rainfall has been variable across the province with all four regions having areas that received less than 2 mm (dark orange on Map 1). In contrast through parts of the Central Region and along the foothills west of Fort Macleod more than 15 mm was recorded. For this time of year, this is enough in the short term to stimulate late season growth of pastures and hay land and perhaps fuel optimism for those planning fall seeded crops. In these areas this represents near normal rainfall for this time of year (Map 2). However, elsewhere, most areas have received below normal moisture over this period, which aids in harvesting, but falls short of getting a good start on building soil moisture reserves for next year’s planting cycle. That being said, there is still ample time to receive much needed moisture between now and next spring.

60-day Precipitation Trends, as of September 20, 2023

Map 3: Looking back over the past 60-days, most lands between the US border and the Yellowhead Highway in the north, have received below average rainfall with roughly 50% of the Central Region and 40% of the Southern Region experiencing at least once in 12 to 25 year lows for this period (Map 3). In contrast, most of the North East has been near normal. Across the North West, conditions have been wetter than normal with a large area located North West of Edmonton, seeing conditions this wet on average less than once in 6 to 12 years. This bodes well for next year’s crop, but in some areas it’s likely causing some immediate difficulty with field access in low lying areas or poorly drained fields. For the most part conditions have turned around through the western and extreme northern Peace Region with most areas received near normal rainfall for this time of year.

Growing Season Precipitation Accumulations as of September 20, 2023

Map 4: This growing season has been difficult for many parts of the Southern Region and the east-half of the Central Region and parts of the northern and western Peace Region, with all these areas having precipitation deficits in the less than once in 50-year low category. Looking out more broadly, much of the eastern portions of the North East Region have also been short of water, with large areas in the once in 3 to 6-year low category. As the harvest progresses the effects on yields will become evident. However, if the timing and amounts of rainfall were favorable in parts of the North East, some of these areas may have done well. With a summer of smoke filled skies and above average temperatures it’s very difficult to speculate on yields before they are “in the bin”. Elsewhere most of the North West received above average moisture and going into fall freeze-up soil moisture reserves will be adequate, ensuring a good start to next year’s growing season.

Perspective

Map 5: October marks a significant drying trend that generally lasts till March (Map 5). By October, there is very little potential for pastures and hay lands to benefit from moisture this year, and from that point forward it’s very much a wait and see scenario for next year’s crop. There are many months ahead for the moisture situation to turn around. The Climate Prediction Center has issued an El Nino advisory and the prospect is good for a strong El Nino this winter and this typically brings a warmer and wetter winter to many parts of Alberta. However, there are been many El Nino years where this generalization does not hold, particularly when looking at the province as a whole. Let’s hope that the dry areas of the province see a relatively warm and wet winter.