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Prescott to Cornwall

Warnings

Forecast

Marine Forecast

Issued 10:30 AM EDT 18 July 2026

Today Tonight and Sunday.

Wind south 10 knots increasing to southwest 15 near noon then veering to northwest 15 this evening. Wind diminishing to west 10 Sunday morning then becoming light Sunday evening.

Scattered showers ending near midnight with a risk of thunderstorms.

Extended Forecast

Issued 03:00 AM EDT 18 July 2026
Monday Wind light.
Tuesday Wind light increasing to southwest 20 knots.
Wednesday Wind northwest 15 knots.

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Map of St. Lawrence - St. Lawrence River marine weather areas Miramichi North Cape Port Menier Roberval Airport Normandin Mistook Jonquière CFB Bagotville Cap-Chat Île Bicquette Charlo North Bay Airport Yarmouth Airport Brier Island St. Stephen Saint John Airport Point Lepreau Greater Moncton Roméo LeBlanc Int'l Airport Miscou Island Kouchibouguac Kouchibouguac Grand Manan Fundy Park (Alma) Bas Caraquet Bathurst Airport Lac Saint-Pierre Pointe-Noire Île-d'Orléans - Quai de St-Jean Pointe-des-Monts L'Assomption Sept-Îles Airport Pointe Claveau Pointe de l'Islet Trois-Rivières Airport L'Isle-aux-Grues Deschambault Île Rouge Montréal-Trudeau Int'l Airport Montréal Metropolitain Airport Lac Memphrémagog Sainte-Anne-de-Bellevue Cap-Rouge Saint-Anicet Baie-Comeau Airport La Pocatière Pointe-au-Père New Carlisle Mont-Joli Airport Gaspé Airport Lake Nipissing - 45152 Rivière-la-Madeleine Beauport Cap-d'Espoir
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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

Prescott to Cornwall

Issued 2:10 PM EDT 18 July 2026 Conditions are favourable for the development of squalls with wind gusts up to 55 knots, frequent lightning, hail and poor to very poor visibility in thunderstorms heavy at times.

Thunderstorms are expected today with strong wind gusts. The strongest thunderstorms are expected this afternoon as a cold front moves through from the northwest.

Large hail can damage vessels and cause injury. Vessels without lightning protection should make their way to shore immediately. 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 10:30 AM EDT 18 July 2026 Today Tonight and Sunday At 10:30 a.m. EDT today low 999 mb located north of Lake Nipissing.
By 10:30 a.m. EDT Sunday low 986 mb located over eastern Quebec.

At 10:30 a.m. EDT today ridge located on a line north-south over
North Dakota.
By 10:30 a.m. EDT Sunday ridge located on a line north-south over
Lake Michigan.

St. Lawrence - St. Lawrence River Area

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Marine Weather for Canada

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