Storm Forecast for Southern Ontario

Wintery weather will continue in Southern Ontario as the week continues, there will be mostly cloud cover and light to moderate snow from Wednesday to Friday continuing with some heavy snow on the weekend in the region.

FIG 1 - Thursday Dec 9 snow Forecast

looking at FIG 1 there will be flurries all over the region with some moderate snowfall accumulating about 10-15 cm in Barrie and Kingston by Thursday. There is a snow squall watch in Barrie for Thursday December 9. We are expecting the snow fall continuation until the weekend.

FIG 2 - Temperature and windchill Forecast

Temperatures are chilly this week with strong windchills mostly during the evenings, Kenora has a high of -3 and a windchill of -14, Thunder Bay is at -1 with a windchill of -12. Looking at FIG 2 we can see most of the cities below the Great Lakes like Windsor, London and Toronto are slightly warmer than the cities north of the lakes, this is as a result of the upper air jet stream located over the lakes serving as a barrier between the cold drier winds from the pole and the warm maritime winds from the ocean. Ottawa is partly cloudy with low chance of snow, this due to the colder temperature not allowing much formation of snow around the area.

FIG 3 - Saturday dec 11 Snow Forecast

On Saturday we are expecting some heavy snowfall with accumulation of 20 - 30 cm around Kenora and Thunder Bay, 10 - 15 cm in Barrie and Kingston and the rest of Ontario should have some light to moderate snow fall. Snow fall will continue to next week and we should have more accumulation by next week Tuesday. This snow is mostly resulting from the moisture supplied to the air mass moving northeast over the Great Lakes, The air masses absorb the moisture and warmth of the lakes resulting into an instability and formation of more squalls on the surrounding area. From FIG 3 we can see the snowfall accumulation coming from the north west. High ways may not be favorable to use during the weekend because of the heavy snowfall accumulation and visibility may be reduced as well.

FIG 4

Winds will be gusty during the weekend resulting from a southward shift of the jet stream and the thunderstorm formation over the Great Lakes. The 200 mbar jet max is over Lake Huron with a value of 150 knots, FIG 4 shows the maximum wind gusts and directions in the region. Winds are gustier around Windsor, London, Toronto and Ottawa, with a maximum of northwest 90km/hr in London as they are closer to the jet. The jet max has a its dip on the southwest of Windsor and is flowing northwest. Winds will continue to be gusty until next week as the storm passes over Southern Ontario.

Keep warm and stay safe folks !