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Cornwall to Montréal

Forecast

Marine Forecast

Issued 03:00 PM EDT 13 July 2025

Tonight and Monday.

Wind south 15 knots diminishing to light this evening then becoming southwest 10 to 15 Monday morning. Wind becoming light Monday evening.

Showers ending near midnight with a risk of thunderstorms. Visibility as low as 1 mile in showers.

Extended Forecast

Issued 06:00 AM EDT 13 July 2025
Tuesday Wind southwest 10 to 15 knots diminishing to light late in the day.
Wednesday Wind light becoming southwest 10 to 15 knots.
Thursday Wind light.

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Weather Conditions

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

There is no ice forecast issued for this area.

Warnings

Watches (In effect)

Squall watch in effect

Cornwall to Montréal

Issued 4:57 PM EDT 13 July 2025 This afternoon and this evening, conditions will be favourable for the development of squalls with wind gusts up to 50 knots, frequent lightning and poor to very poor visibilities caused by thunderstorms at times strong.

Mariners are advised to prepare for potential squalls. Vulnerable vessels are most at risk and should seek safe harbour if underway. Delay travel or if underway, reduce speed or return to port if safe to do so.

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 13 July 2025 Tonight and Monday At 3:00 p.m. EDT today low 988 mb located over James Bay.
By 8:00 p.m. EDT Monday low 987 mb located over the Ungava
Peninsula.

At 3:00 p.m. EDT today trough located on a line northwest-southeast
over Lake Saint-Jean.
By 8:00 p.m. EDT Monday trough located on a line northeast-southwest
over Havre Saint-Pierre.

Great Lakes - Lake Huron Area

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