The signs of winter are popping up all over Canada as the first significant snow for many areas came during the past weekend and temperatures plummeted as low as minus 25 C (minus 13 F) for some areas a couple of days ago. A new low pressure area promises to bring some light to moderate snows to the region Friday into early Saturday.
It may only be early to mid-November, but some winter cold appears to be on tap for central and eastern areas of the Prairies by early next week as an arctic origin air mass arrives from northwest Canada. The core of this cold air is likely to pass across Ontario but readings as much as 5 to 10 degrees C (10 to 20 F) below normal are quite possible for Saskatchewan to Manitoba by Monday and Tuesday. Alberta may escape the significant cold, but will see readings at least several degrees below normal.
The expanding snow cover aids in the cold weather since it helps any daytime heat to escape to space more quickly during the longer nights and also helps to reflect sunshine back upwards during the day.
Winter has come upon us quickly during the past week and the reasons can be tied to the changing jet stream pattern. During the recent week we have seen more ridging develop along the West Coast of Canada and through the eastern Gulf of Alaska and this has helped send some colder weather southward to the Prairies from the expanding reservoir of cold air across northern Canada.
At the same time, the cold pushed into the region low pressure which slid along the U.S./Canadian border area and brought the past weekend snow to many areas. Another such system is expected to pass through the region Friday into early Saturday and may bring several inches (4 to 8 cm) of snow to central and northern areas. Temperatures may be mild enough closer to the U.S. border so that mixed precipitation or rain falls.
The prospects for long-lasting cold weather and snow do not appear high at this point. Most of the computer model guidance indicates a moderating weather pattern again by late next week into the third week of November as increased influence of Pacific air occurs.
Very cold air is expected to remain pooled across Alaska and far northwest Canada later this month so we will have to watch for possible rapid changes in our temperatures later this month.
Doug Webster can be reached at firstname.lastname@example.org
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