Arctic high pressure dominates once again

Issued: Monday, Mar. 16, 2015 – Covering: Mar. 18 – Mar. 25, 2015

snow cover maps of north America

Given all the trouble the weather models had with last week’s forecast, they ended up hitting it pretty much right on the mark. An intense low moved in from the Pacific and tracked across the southern Arctic last weekend. That, combined with a ridge of high pressure, brought the warmest weather of the season to all regions. For this forecast period, it looks like the weather pattern will shift back to the old familiar one we’ve dealt with for the last month and a bit. Fortunately, with the lack of snow cover over southern regions, temperatures won’t be all that cold.

This forecast period is going to be dominated by a large arctic high that is forecast to slowly drop southward. This high will begin to nudge into our area Thursday, with the centre of the high crossing over us Saturday and Sunday. We’ll see plenty of sunshine with this high, and for those areas that are snow free, this will allow daytime temperatures to warm up to about 5 C more than snow-covered areas. But even the snow-free areas will be cool, especially over the weekend when the high is directly overhead. We should expect to see highs drop to below freezing on Thursday and by the weekend, highs will struggle to make it to around -4 C, with snow-covered regions in the -8 C range. Overnight lows will also be cold, with temperatures dropping to around -16 C on the weekend.

Once this high slides by to the southeast early next week, we’ll see temperatures moderate as the flow becomes southwesterly. Temperatures will start to warm up late on Sunday, and by Monday, daytime highs should be back above 0 C. We’ll have to keep an eye out for a possible system that could bring a mix of rain and snow on Wednesday, but that’s a long way off, and so far this year we’ve either been missing these systems or they don’t develop as forecast.

Usual temperature range for this period: Highs, -8 to +6 C; lows, -21 to -4 C. Probability of precipitation falling as snow: 90 per cent.

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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