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Cornwall to Montréal

Warnings

Forecast

Marine Forecast

Issued 03:00 PM EDT 12 August 2026

Tonight and Thursday.

Wind west 10 to 15 knots becoming light this evening then becoming westerly 15 Thursday morning. Wind diminishing to light Thursday evening.

Scattered showers ending near midnight with a risk of thunderstorms. Scattered showers Thursday late in the day.

Extended Forecast

Issued 06:00 AM EDT 12 August 2026
Friday Wind light becoming northwest 10 to 15 knots in the morning.
Saturday Wind light.
Sunday Wind light.

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Map of Great Lakes - Lake Erie and Lake Ontario marine weather areas Harrow AAFC Hamilton Munro Int'l Airport CFB Trenton Erieau Toronto City Centre Airport Point Pelee Peterborough Municipal Airport Burlington Lift Bridge Point Petre Cobourg Oshawa Executive Airport South Lake Huron - 45149 Port Colborne Brockville Gore Bay-Manitoulin Airport North Bay Airport Greater Sudbury Airport Killarney Sault Ste. Marie Airport Ajax - 45159 North Channel - 45154 Lake Nipissing - 45152 Lake Simcoe - 45151 Windsor Airport Lake St Clair - 45147 South Georgian Bay - 45143 Port Colborne - 45142 Grimsby - 45139 Georgian Bay - 45137 Prince Edward Point - 45135 Port Stanley - 45132 Welland-Pelham Grenadier Island Kingston Airport Collingwood Lagoon City Muskoka Airport Parry Sound Harbour Lake Simcoe Regional Airport Wiarton Airport Western Islands Sarnia Chris Hadfield Airport Vineland Station Southeast Shoal St. Catharines / Niagara District Airport Goderich Port Weller Long Point Tobermory
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land station Land Station
Ice Conditions

There is no ice forecast issued for this area.

Warnings

Watches (In effect)

Squall watch in effect

Cornwall to Montréal

Issued 4:47 PM EDT 12 August 2026 Conditions are favourable for the development of squalls with wind gusts up to 35 knots.



Mariners are advised to prepare for potential squalls. Vulnerable vessels are most at risk and should seek safe harbour if underway. Consider delaying or postponing travel in areas under the Squall Watch.

Please continue to monitor alerts and forecasts issued by Environment Canada. For more information monitor Canadian Coast Guard radio or Weatheradio stations.

Synopsis

Technical Marine Synopsis

Issued 3:00 PM EDT 12 August 2026 Tonight and Thursday At 3:00 p.m. EDT today low 997 mb located over the Strait of
Belle Isle.
By 8:00 p.m. EDT tonight departing low 998 mb located over northern
Newfoundland.

At 8:00 p.m. EDT tonight trough located from the low to Saguenay
River.
By 8:00 p.m. EDT Thursday trough located from Labrador to New
Brunswick.

At 8:00 p.m. EDT Thursday approaching ridge located over
northwestern Ontario.

Great Lakes - Lake Erie and Lake Ontario Area

Another Region

Marine Weather for Canada

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