Another growing season comes to an end

A dry summer generally left workable soils, even after September’s wet second half

Another month has come and gone and it’s time to look back at our weather so far this fall. To start off, we saw the end of the growing season across most regions last week, as temperatures fell just below freezing last Thursday morning. I know at my place the thermometer measured an overnight low of -0.6 C, but looking at the garden there were only a few minor indications of frost. That said, the official numbers are the official numbers, so here are the final frost-free season lengths for the three major centres in Manitoba.

It was a remarkably consistent frost year with all three locations seeing both the last spring frost and the first fall frost within a couple of days of each other. While this year’s frost-free season wasn’t as long as last year’s, we still saw a frost-free season that was around two weeks longer than average.

Looking back at September, it was a warmer-than-average month. The biggest driver behind the warm September temperatures was the extremely warm start to the month. The first two weeks saw temperatures that were more like summer than early fall. Daytime highs soared into the low to mid-30s on Sept. 12 and broke numerous daily record highs. While we did see a few cool periods during the second half of the month, warm fall temperatures seemed to win out. When all the numbers were added up, the Winnipeg region was the absolute and relative hot spot, with a mean monthly temperature of 14.2 C, which was 1.5 C above its long-term average. The Dauphin region came in a close second with a mean monthly temperature of 13 C, which was 1.3 C above average. Last, but not least, was the Brandon region, which saw a mean monthly temperature of 12.7 C or about 0.9 C above the long-term average.

Looking at precipitation across the province, the dry weather we saw this summer finally broke during the second half of the month. Several systems brought significant rains during the last couple of weeks of September. Most notable were the scattered thunderstorms that brought upward of 30 to 40 mm on Sept. 22. Most of southern Manitoba saw rainfall amounts of around 60 to 80 mm in September, about 15 to 30 mm greater than average. The Dauphin region was the dry spot, with a report of about 50 mm of rain in September, or about five mm below its long-term average. Thanks to the dry summer, even the wettest areas could handle the rain, with most areas reporting workable soil conditions.

LSF = last spring frost; FFF = first fall frost; FFS = length of frost-free season, in days. * - Denotes range of expected length of frost-free season, in days, 90 per cent of the time and 10 per cent of the time.

Who called it?

Overall, it was a warmer- and wetter-than-average month across most of Manitoba. Looking back at the forecasts, both of the almanacs were off, with predictions of cool and wet conditions. NOAA, CanSIPS, CFS, Environment Canada and my forecast all called for a warmer- and drier-than-average month. This means nobody was able to correctly predict this September’s weather. The question now is, does this mean our late-fall and early-winter forecast will be off as well?

According to the Old Farmer’s Almanac we will see a colder-than-average remainder of fall and the first part of winter, along with near- to slightly below-average amounts of rain/snow. The Canadian Farmers’ Almanac also calls for colder-than-average temperatures as it mentions cold several times in its discussion. It also appears to call for above-average amounts of precipitation as it mentions stormy, wet, snowy conditions several times.

Moving on to Environment Canada, it calls for a better-than-average chance of seeing slightly warmer-than-average temperatures along with slightly higher-than-average amounts of precipitation. The CFS model calls for a warmer-than-average October that will then transition to a colder-than-average November and December. Along with the colder temperatures will come near-average amounts of snowfall. The CanSIPS model calls for above-average temperatures to continue, but will slowly cool toward more average values by December. It also follows the CFS models and is predicting near-average amounts of precipitation.

Finally, here is my meagre attempt at forecasting. With no strong global driving forces in place going into this winter, I will have to rely on persistence. This means that until we see a definite shift in the weather pattern that we’ve been in over the last several months, there is no reason to expect it to change. So, I will go with a forecast for slightly above-average temperatures along with near- to slightly below-average amounts of precipitation. As usual, all we have to do now is sit back and see what will happen. As for the rest of the winter, I will take a look at that in a month or so, but my gut is still saying we are long overdue for an epic winter storm.

About the author

Co-operator contributor

Daniel Bezte

Daniel Bezte is a teacher by profession with a BA (Hon.) in geography, specializing in climatology, from the U of W. He operates a computerized weather station near Birds Hill Park.



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