A snow fall warning continued for parts of southwestern Ontario into Wednesday morning, but ended as the storm slowly moved east.

Around 4:45 a.m., Environment Canada changed the area under the snow fall warning. Caledon, Vaughan, Markham, northern York and Durham Regions as well as Dufferin and Innisfil are now in the hardest hit area.

A large moisture laden low pressure system from Texas continues to track northeast towards across southwestern Ontario.

Wet snow driven by winds gusting to 60 km/h has covered the area overnight.

The precipitation started out as various sloppy mixtures of rain and wet snow. As the storm centre got closer, mostly wet snow hit the area as the temperature dropped to the freezing mark.

The snow has been quite heavy at times into Wednesday with peak snowfall rates of 2 to 5 cm per hour during the most intense part of this storm. Environment Canada has already received several reports of snow accumulating at the rate of several centimetres per hour in heavy bursts of snow. Total snowfall amounts of 15 to 20 centimetres are likely by noon on Wednesday, although amounts near the lake Ontario shore will be less.

This storm will likely have a significant impact on travel especially Wednesday morning. Driving conditions have deteriorated on some roads. Visibility may be reduced to less than 250 metres in very heavy snow. Untreated roads will quickly become snow covered and slippery. Travel plans should be altered accordingly.

Toronto's Pearson airport is reporting about 20 per cent of its arrivals and departures have been cancelled or delayed, Travellers are advised to check ahead.