Ontario Weather Review
The early sales of shovels and snow blowers may have brought a smile or two to some retailers in Ontario, what with significant snowfall making an abnormally early appearance. Considerable amounts of snow fell in traditional snow-belt areas, so a table of high single-day totals for Ontario is part of this report. In some cases, more snow fell in one day than would normally fall during an entire month. These large snowfall amounts resulted in the highest monthly totals for London since 1970 and for Sault Ste. Marie since 1989.
The snowfall in these areas brought their monthly precipitation – that is, the combined amounts of rain and snow – to high levels as well, but generally the rest of the province had near-normal precipitation levels or even drier-than-normal readings.
Temperatures for Northern and Central Ontario were on the warm side this past month, with some locations reporting temperatures 2 to 3 degrees above normal. The rest of the province was near normal or slightly warmer than normal.
While not really qualifying as severe weather, the stretch of record-breaking warmth and sunshine that occurred in many localities across the province from November 3-7 was definitely noteworthy. A number of single-day records for high temperatures fell during this period in both Northern and Southern Ontario. Aside from record-breaking temperatures, the warm breezes from the southwest were also accompanied by lots of sunshine. November is usually known as a month where cloudy conditions dominate. So, a totally sunny day is a bit of a rarity – let alone being able to string three or more consecutive days of sunshine, as some areas did during this period near the start of the month.
Then, as if to remind us that it was November and not September, Mother Nature brought cold air back with a vengeance. Temperatures plummeted across the province just past the mid-point of the month, with many areas experiencing overnight temperatures more than 10 degrees colder than normal. The coldest areas were in Northwestern Ontario and to the north of Lake Superior, where overnight temperatures bottomed out between minus-21 degrees Celsius and minus-25 during the early morning hours of November 21 and 22.
This influx of arctic air was a perfect set-up for the lake-effect snow engine for regions in and around Sault Ste. Marie, as well as in the traditional snow belts in Southern Ontario near Lake Huron and Georgian Bay. Lake-effect snow events in late November and early December can be particularly powerful, given the marked contrast between the cold air flooding down from the northwest and the relatively much warmer waters of the ice-free Great Lakes. Forecasters in the Ontario Storm Prediction Centre in Toronto realized that the snow squalls generated over Lake Huron and Georgian Bay on November 20 and 21 had the potential to dump massive amounts of snow…leading to words like “colossal” being mentioned in the snow squall warnings for some areas. One particularly intense and long-lived band of snow came in off Lake Huron late on November 20 and persisted into the early morning hours of November 21. It dumped some 75 centimetres of snow in communities in Northeastern Lambton County, just south of Pinery Provincial Park. These huge accumulations led to the temporary closure of Highway 402 between London and Sarnia and a number of people stranded in their vehicles required rescue by the Ontario Provincial Police aboard snowmobiles.
Unusual mean temperature readings:
|Location||Mean Temp||Normal||Difference||Warmest Since|
Record precipitation (mm):
Unusual precipitation (in millimeters):
Single-day snowfall highlights for November 2008
|Site||Date in November||Total snow (cm)|
|Sault Ste. Marie||21||33.2|
|Sault Ste. Marie||19||24|
For more information, please contact:
Environment Canada -- Ontario
- Date Modified: