Much colder weather set to invade southern Quebec

Cold, damp weather will return to Montreal Saturday, with perhaps the first snowflakes of the season early next week.

Friday has turned into a spectacular late October day across southern Quebec and eastern Ontario. Temperatures have warmed into the low 20s (70s). The record high for Montreal for October 23 was 25C (77F) set in 1979. We will likely fall just short of that, but it will be pleasant nonetheless. Accompanying the warmth is some much needed sunshine. It has been a damp, chilly and at times rainy week so far. So far this month 93.8mm of rain has fallen at Trudeau Airport.

Unfortunately the nice weather is only here for the day. High pressure is nudging into the region for less than 24 hours. It will be followed by a strong cold front sliding southeast from northern Ontario. The front will bring with it the coldest air of the season to date. For the last week, deep arctic air has been diving south into the Prairies and all the way into the US heartland. Heavy snow has fallen across portions of Alberta, Saskatchewan and into the US Rockies, Plain states and even the upper Midwest. That snow will slip even further south impacting portions of the southern plains and rockies over the upcoming weekend. Temperatures have been running 10 to 20 degrees Celsius below normal. Winter is now leaning on eastern Canada.

Tonight's cold front will produce showers and perhaps an isolated thunderstorm overnight. The big story will be the drop in temperatures. Montreal will fall from the middle 20's for highs Friday, into the single digits by Saturday morning and not move much after that. Overnight lows will be at or just slightly below freezing, with a high on Sunday of only 5C (41F). We may see some sunshine Sunday, otherwise clouds will prevail for most of the weekend. The current normal high/low for Montreal is 10C/2C (50F/36F)

First snowflakes for Montreal?

The cold air will remain in Montreal through next week. There will be several chances for precipitation, including perhaps some wet snow late Sunday night or early Monday morning before changing to rain. I don't expect any significant accumulations in the Montreal region, but I am watching it closely. Another chance for wet snow may come Wednesday night, but again I don't believe this is the first big storm.

Temperatures will remain below normal into the Halloween weekend.