A return to cooler weather in May?

The CanSIPS model expects near- to above-average precipitation in May

Idon’t know about you, but being stuck at home working for a whole month actually made the month go by faster; seriously, it’s already May! That means it’s time for our look back at last month’s weather and our look ahead to see what the weather prognosticators say for the rest of May and June.

When I try to come up with a term to describe April’s weather, the word strange comes to mind. It began cold and snowy across Manitoba and just plain cold across the rest of the Prairies. The cold weather continued until just past the middle of the month, but thanks to lower-than-average snow cover going into the month, most regions were snow free. This, I think, always makes it feel warmer than it is, especially when the sun is shining. Then, during the last week of the month, we finally saw above-average temperatures move in, which helped, at least a little, to erase the memories of the cold start to the month.

When all the numbers were added up, April 2020 ended up being colder than average right across the Prairies. As I pointed out in an earlier article, while it was a cold start to April, it wasn’t a record-cold start. Now, combine that with above-average temperatures to end the month and you end up with a colder-than-average month, but nowhere near record cold.

Mean monthly temperatures for April were surprisingly similar right across the Prairies. They ranged from the coolest of -0.6 C in Saskatoon to +2.2 C in Calgary. If you look at the monthly departure from average temperature map I included on this page, you can see the coldest readings, compared to average, were found in the region stretching from Regina northwestward to around Edmonton. The warmest regions were located in far northwestern and southwestern Alberta along with central and eastern Manitoba.

Moving on to precipitation: overall, April was a dry month across the Prairies, with precipitation values ranging from a low of 2.1 mm in both Edmonton and Peace River, to a high of 32.6 mm in Brandon. Along with the temperature map I have also included a map showing the total accumulated precipitation for the month of April. You can see on the map that the region stretching from northwestern Alberta southeastward to Regina saw amounts that were generally less than 15 mm, with large areas seeing less than 10 mm. Far southwestern Alberta and southern Manitoba both saw higher amounts in April. For Manitoba, most of this precipitation came in the first few days of the month, leaving the rest of the month fairly dry.

Who called it?

To sum April up, it was cold and dry across most of Alberta and Saskatchewan, and cold with near- to slightly below-average precipitation in Manitoba. Looking back at the different forecasts, the winner looks to be the CFS model, as it predicted a cold start to April with a slow warming trend toward average temperatures in May along with above-average precipitation across eastern regions in April, with near average elsewhere. While it was off on the precipitation amounts, it did get the general trend correct.

Now, let’s see what’s up for May and June. According to the Old Farmer’s Almanac, May is going to see near-average temperatures and rainfall. The Canadian Farmers’ Almanac appears to call for near-average temperatures in May along with near- to above-average rainfall as it mentions fair several times, but also mentions very unsettled a couple of times. June looks like it will be near- to slightly above-average temperatures along with near-average rainfall. It mentions fair conditions to start the month, then becoming hot by the end of the month.

Now, on to the computer models. NOAA calls for near-average temperatures over the next two months with a chance of above-average temperatures across Alberta. Precipitation looks to be near average. The CFS model calls for a cool start to May, transitioning to above-average temperatures for the second half of the month with those above-average temperatures continuing into June. Its precipitation forecast is for above-average amounts in early May followed by near- to below-average amounts for the rest of the forecast period.

Next up is CanSIPS. This model calls for slightly above-average temperatures across the south-central Prairies in May with near-average temperatures elsewhere and near- to above-average amounts of precipitation. For June, the model calls for near- to slightly above-average temperatures and precipitation.

Finally, my thoughts: I am leaning toward near- to slightly below-average temperatures in May along with near-average rainfall. This will transition to near- to slightly above-average temperatures in June along with near-average rainfall. Which forecast are your bets on?

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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