Monday, November 1st 2021, 8:47 pm - September and October may have felt similar across Canada, but the pattern won't hold up for a third straight month as a reversal takes shape in November.
Fall has featured a rather consistent pattern so far, with above seasonal temperatures dominating east of the Rockies and colder than seasonal temperature across B.C. and the Yukon.
The temperature anomaly map for October (shown below) looks much like the map we showed a month ago for September.
However, this pattern started to break down at the end of October and the national temperature pattern as we start off the month of November is in the process of becoming the opposite of what we have seen for the past two months.
FLIP-FLOPPING WEATHER PATTERNS
This has brought a brief period of drier and mild weather to B.C. and most of Northern Canada. Meanwhile, a shot of much colder weather is spreading from the Prairies to the Great Lakes and then into Atlantic Canada. Temperatures won’t be unusually cold for this time of year, but still quite a contrast to what we have seen so far this fall and cold enough for bands of lake-effect snow east of Lake Superior, Lake Huron, and Georgian Bay.
However, this pattern reversal will be temporary. Very mild weather will quickly spread back across the Prairies during the first few days of November. Above seasonal temperatures will continue to spread east into Ontario, Quebec and eventually into Atlantic Canada during the second week of November and continue through mid-month. Meanwhile a stormy pattern will quickly return to B.C. with heavy rain and an abundance of alpine snow for many ski areas.
It is important to keep in mind that “normal” temperatures continue to quickly fall through the month of November, so this period of milder weather will not be as warm as what we saw during October. However, this should provide those living east of the Rockies with an opportunity rake the leaves and wrap up any yard work that they are hoping to get done before winter arrives.
SECOND HALF OF NOVEMBER SEES LATE FALL, EARLY WINTER TRANSITION
As we progress through the second half of November, we expect that we will transition into the late fall and early winter pattern that we highlighted in our Fall Forecast and in our winter sneak peek.
A milder and drier pattern is expected for B.C. and a changeable pattern is expected for the western Prairies. Meanwhile, a much colder pattern is expected to develop well before the end of the month -- from the eastern Prairies to Ontario and Quebec, and at times into Atlantic Canada.
The arrival of Arctic air crossing the relatively warm waters of the Great Lakes should help to trigger substantial lake-effect snow for the snowbelt areas.
This pattern is expected to dominate through the month of December. For Western Canada this means that the arrival of consistent cold weather will be delayed. However, across Eastern Canada this pattern should bring more consistent cold for late November and December than we have become accustomed to seeing in recent memory.
Stay tuned to The Weather Network for the latest forecast updates as we progress through November.