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Cold February ahead… but not like last year’s

The last 15 years have shown an unusually large number of warm Januarys

Cold February ahead… but not like last year’s

For the 11th time over the last 15 years, this January saw above-average temperatures across all of agricultural Manitoba. Along with above-average temperatures came a mixed bag of precipitation totals, with some regions seeing above average, others near average and, you guessed it, some areas continuing to see below average. The one positive during January was that most areas did see at least some significant snowfall.

Let’s begin our look back with temperatures. It was a warm month across southern and central Manitoba. After a slightly colder-than-average fall, and then some really cold temperatures for parts of December, the big question leading into January was whether it was going to end up being a cold month. I think, much to most people’s surprise and happiness, the opposite happened. Mean monthly temperatures measured at our three main locations ranged from 1.1 C above average in Dauphin and 2 C above average in Brandon to 3.5 C above average in Winnipeg. Interestingly, as I pointed out at the beginning of the article, over the last 15 years we have seen a disproportionally large number of warm Januarys, which makes it just a little easier to get through the winter, unless we see the extreme cold in February like we saw last year. More on that later in the article.

As for precipitation, Brandon was the “wet” spot with about 21 mm of water-equivalent precipitation, which comes in a little above average. Dauphin saw about 12 mm, which was a little below average, and Winnipeg reported around 11 mm, which was below its average of 20.

What brought on all this warmth? During January, the polar vortex — a pool of cold air surrounded by a ribbon of high-speed winds in the upper atmosphere — has been strong, consistent, and sitting over the pole. This, in turn, helps to keep the coldest air bottled up well to our north. One measure of the strength of the polar vortex is an index known as the Arctic Oscillation.

This is a measure of the pressure difference between the upper and lower Arctic. This January saw index values that have averaged above +2.0, which has only occurred four times since 1950. This warm pattern is not just across North America, as much of Europe and Asia have seen warmer-than-average temperatures over the last month or so.

Who called it?

This leads us to the latest medium- to long-range forecasts. But before we dive into those to see what has changed, we need to look back to see whose January forecast was the best. For the first time that I can recall, and my memory is bad, none of the forecasts were correct! They all called for colder-than-average temperatures. If we had to pick who was the closest, then the nod would go to CanSIPS (Environment Canada) and my fore- cast, as both called for near- to slightly below-average temperatures along with near-average amounts of precipitation.

If you remember back to the article (it was only a couple of weeks ago), you might remember me pointing out that it seems to be a tough period to try and figure out the long-range forecast. There just don’t seem to be any strong signals forcing the forecast to lean in any one direction. With that said, a few pieces might now help steer the long-range forecast, at least over the next month.

Before digging into that, let’s review the long-range forecasts that don’t change over time: the two almanacs. The Canadian Farmers’ Almanac appears to still call for near-average temperatures and snowfall in February. The Old Farmer’s Almanac calls for a colder- and wetter-than-average February.

Next we move on to the computer models, which are updated, depending on the model, every week to once a month. NOAA is sticking to its guns from back in early January and calling for colder-than-average temperatures and above-average snowfall. The CFS model, which updates every week or so, has been giving mixed signals. Its six-week forecast, which shows weekly temperature trends out to early March, calls for below-average temperatures every week in February, while its monthly forecast calls for above-average temperatures in February. I think I will lean toward the weekly forecast of below-average temperatures. It does show above-average temperatures moving back in for March. As for precipitation, it calls for near- to slightly above- average amounts in both February and March. Next on the list is the CanSIPS model, calling for slightly below-average temperatures in February followed by slightly above-average temperatures in March. Precipitation is forecast to be near average.

Finally, my forecast: With the latest medium-range forecasts showing colder air moving in, the fact that the Arctic Oscillation usually doesn’t stay strongly positive for long periods of time, and hints of a building ridge of high pressure off the Pacific coast, everything seems to point toward a colder-than- average February.

I don’t think we will see the bone-chilling weather we saw last February. In fact, even with a setup that should bring cold weather, there are hints that we will continue to see the coldest temperatures stay either to our west or get shunted to our east. It does look like March will see warmer-than-average temperatures, but that’s just because I want to see warmer-than- average temperatures.

Precipitation forecasts are always tough, but it looks like February will be drier than average and March… I’m guessing/hoping it will also be dry.

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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