A slow-moving low currently over Illinois is combining with Arctic air over southern Ontario to produce a messy mix of snow or rain, ice pellets and freezing rain in the regions under warning, including Huron County. It is laying down a coating of 2 to 4 cm of fresh snow and ice pellets in a swath from Toronto toward Lake Huron. This first round of wintery weather will retreat to the east by early afternoon, introducing a break in the steady precipitation for the afternoon. However, some sporadic mixed ice pellets and freezing rain can still be expected.
The main precipitation is expected to arrive this evening. Freezing rain and ice pellets are expected to become fairly widespread. It may well fall heavy at times and be accompanied by a few rumbles of thunder. It will change to rain later tonight in most areas as temperatures rise above the freezing mark.
Poor travel conditions are expected over the duration of this event. However, with temperatures hovering near the freezing mark, treated roads will tend to be merely wet while untreated roads may be somewhat slippery. Also, with the break in precipitation this afternoon, the drive home from work may not be as difficult as previously thought.
Of greater concern is the risk of widespread power outages this evening from downed tree limbs and power lines due to significant ice accumulation combined with northeast winds gusting to 60 km/h. Freezing rain amounts up to 10 mm are quite possible in many areas with some regions possibly exceeding 20 mm. The heavier amounts would be primarily to the west and northwest of the Greater Toronto area.
There is still some uncertainty as to the extent of the cold air. This will have an impact on how much falls as ice pellets versus freezing rain. Freezing rain will have a higher impact with power outages and slippery roads and sidewalks. Although a few centimetres of ice pellets and snow is expected, it is more of a nuisance for travel rather than a serious hazard.