WINGHAM, ONT. -- Batten down the hatches. It's going to be a long, snowy night in parts of Midwestern Ontario.

Strong westerly to northwesterly winds with gusts to 70 km/h are generating blowing snow and poor visibility.

Environment Canada has just posted a Blizzard Warning for Saugeen Shores, Kincardine, Hanover and Dundalk.

As much as another 50 centimetres of snow could fall in southern Grey and southern Bruce counties between Thursday afternoon and Saturday morning.

The squalls are being fuelled by a wide open Lake Huron that has very little ice cover, and 60-70 km/h winds.

The low pressure system that moved by Wednesday brought a significant swath of snow to Southern Ontario.

Snowfall amounts on Wednesday varied between 10 and 25 cm:

Mount Forest 17.8 cm

Wingham 15-18 cm

Toronto 15 cm

Kitchener 14.2 cm

Strathroy 13 cm

London 12 cm

A blowing snow advisory is in effect for London, Parkhill, eastern Middlesex County, Oxford, Brant, southern Wellington County, Region of Waterloo and Dufferin County.

Visibility in blowing snow may be reduced to less than a few hundred metres.

Snow squall warnings are in effect for Huron, Perth, northern Grey and the Bruce Peninsula

Snowfall rates under the most intense bands may reach or exceed five centimetres per hour at times. Some areas may see snowfall amounts in excess of 40 cm by Friday morning.

There is also a flood watch for the shores of Lake Huron.

Road closures and event cancellations are in effect throughout the region Thursday night, especially in the areas under the blizzard warning