A Major Pattern reversal is underway across Western Canada. Cold air will descend from Northern Canada beginning Friday, coinciding with an extended period of heavy snowfall.
Our forecasting team will be closely monitoring the progression a major winter storm beginning Thursday evening. The Winter Storm isn’t expected to bring heavy snowfall rates, but rather an extended period of light-moderate snow over the next 48 hours.
The heaviest snowfall totals are expected through the Rockies; across British Columbia and Alberta. Where in excess of 50cm of snow is expected to fall. Even major cities, such as Edmonton won’t escape the wintry weather. With 30 or more centimeters projected to fall, over the next couple days.
An area of low pressure will strengthen as it tracks through the Upper Midwestern United States. Bringing accumulating snow and gusty winds across Northwestern Ontario. Summer-like heat & humdity returns to Southern Ontario.
TIMING & ACCUMULATIONS
Snow flurries will begin mixing in along Highway 17 late Wednesday evening. With wet snow falling by Thursday morning. By Thursday afternoon, anywhere along and south of Highway 11 will likely be seeing rain.
North of Lake Superior, precipitation will fall as a cold rain with gusty winds. Including the Thunder Bay area, where cold rain and gusty winds will lead to a miserable day.
By Wednesday afternoon or late evening, cold air will wrap around the deepening system. Heavy snowfall will begin accumulating in a line from Kenora to Dryden to Sioux Lookout to Pickle Lake. Continuing into extreme Southeastern Manitoba. Moderate to heavy snowfall and gusty winds will persist, increasing in coverage across Northwestern Ontario through the day Thursday.
Projected amounts are subject to change based on the track & timing of the low + Hurricane Michael. Current guidance suggests a large swath of 20-30cm. 30-40cm could fall locally.
Actual accumulations will be largely dependant upon key factors: track of the low, temperature, and snowfall ratios. Moisture won’t be an issue with tropical moisture from Hurricane Michael.
While Northwestern Ontario deals with heavy snow, Northeastern Ontario will be dealing with heavy rainfall. A large swath of 50-75mm is expected East of Lake Superior.
THE TALE OF TWO SEASONS
As Northern Ontario deals with heavy rain and snow, Southern Ontario will get one last blast of summer. Temperatures Wednesday will likely be soaring into the mid or high-20s. With abundant humidity making it feel into the 30s. Forecast temperature & humidity readings will challenge all-time October records Tuesday and Wednesday.