Wednesday, October 03, 2012

Summer warmth - winter cold

A dark webcam image from early this morning in Canmore, Alberta where it is -2C with light snow. You can see the snow covering the ground and the buildings. (
It is October, and like April it is a month of serious transition. Therefore it is quite possible to have 30C one week and snow the next. The residents of southern Manitoba will experience that scenario this week. After the warmth of last weekend, many areas of southern Manitoba, northwest Ontario as well as adjacent North Dakota and Minnesota are looking at the first snowstorm of the season. Winter Storm Watches are flying this morning as low pressure is forecast to take shape over the northern Plains and strengthen as it heads across Lake Superior. Cold air and increasing north winds on the backside of the system will change the rain to wet snow with 10-15cm (4-6 inches) possible by Friday morning. The trailing cold front is already spreading snow across southern Alberta this morning with several centimteres accumulating overnight in the near Canmore, Alberta, the foothills and western Montana.

Meanwhile here in the east it is perhaps summer's last stance. It is a mild and muggy morning with a southwest flow of moisture streaming north from the Gulf of Mexico and into Ontario and Quebec. The elevated humidity and long nights have led to widespread fog along the Eastern Seaboard and into our region. The fog will dissipate followed by a partly sunny and warm day with highs near 21C (70F). The above normal temperatures are here to stay until that aforementioned cold front arrives by late Friday. From a precipitation point of view, we are looking at a slight risk of showers today with an elevated risk of showers and thunderstorms by Thursday. The weather will remain unsettled into the weekend with more showers, and turning much colder with highs not getting above 10C (50F) on Sunday and Thanksgiving Monday.

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