Strong winter storm part of contrasting February pattern
Meteorologist, PhD
Thursday, February 2, 2017, 3:42 PM - The signature of this winter so far has been well defined periods of contrasting weather patterns.
The first three weeks of December featured colder than normal temperatures from coast to coast. Then, in contrast, January brought an extended thaw for most of Canada. Experiencing this, we expect that the remainder of winter will continue to feature back-and-forth swings in temperature, but with some key differences which I will outline below.
As we start February there are once again below-normal temperatures across much of Canada, albeit not as cold as what we saw during December. This pattern will continue well into next week. The map below shows a model forecast for February 6–10th with the various shades of blue and green highlighting below normal temperatures for the week as a whole.
Image: Weatherbell
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Impactful winter storm: Timing and type
Looking ahead, an impactful winter storm will impact much of southern Canada next week. Snow is likely across southern B.C. and the Prairie provinces. Much warmer weather just south of the border will surge north and bring a brief warm-up and messy weather (snow, ice and rain) from southern Ontario to Atlantic Canada ahead of another shot of Arctic air which will spread into the region late in the week.
As we look ahead to the middle of February, yet another contrasting pattern change will evolve. Milder Pacific air will spread across the Prairies during the end of next week and weekend. The map below shows temperature anomalies for next Saturday morning (February 11th).
Image: Weatherbell
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The orange and red colours show above-normal temperatures across B.C. and the Prairie provinces in contrast to the Arctic air across most of eastern Canada.
As we continue through the second weekend and into Valentine’s Day, the milder weather will continue to spread east, leading to another widespread thaw.
The question is: Will this thaw last as long as our January thaw?
Numerous models say yes – the thaw will dominate the national weather pattern for the second half of February, much like it did during January. However, there are also strong indications that a blocking pattern will develop in the upper atmosphere over the Arctic, especially over Greenland.
If that does indeed occur (and I think that it will), it will be very difficult to sustain a mild pattern from the Great Lakes to Atlantic Canada. The set-up is reminiscent of last April when the models were mistaken in showing a persistent warm pattern despite a similar blocking pattern.
So, who sees spring first?
As a result, we expect that we will continue to see back and forth swings in temperature during the second half of February and through much of March as milder air attempts to spread north and east, while Arctic air surges south from time to time.
However, in contrast to the first half of winter we expect that with the back and forth temperatures the balance will tip towards mild in the west and towards cold in the east.
Residents of the south coast of B.C. are usually the first to see spring weather arrive and it looks like that will once again be the case this year – and likely that will be welcome by many after experiencing a more classic Canadian winter across that region.
