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ON- Lake Ontario

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forecast for the saint lawrence river
including the thousand islands region
national weather service buffalo ny
1003 am edt mon apr 27 2026


slz022-024-272100-
saint lawrence river from cape vincent to saint regis
1003 am edt mon apr 27 2026

.this afternoon...light and variable winds. sunny.
.tonight...light and variable winds becoming south 5 to 10 knots.
mainly clear early, then becoming partly cloudy. 
.tuesday...south winds 5 to 15 knots. a chance of showers in the
afternoon. 
.tuesday night...south winds 5 to 15 knots becoming southwest. a
chance of showers. 
.wednesday...southwest winds 10 knots or less becoming west.
showers.
.thursday...northwest winds 5 to 10 knots. rain showers. 
.friday...northwest winds 5 to 15 knots becoming west. a chance
of rain showers during the day, then a chance of rain and snow
showers friday night. 

$$
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open lake forecast for lake ontario
national weather service buffalo ny
1002 am edt mon apr 27 2026

for waters beyond five nautical miles of shore on lake ontario

waves are the significant wave height - the average of the highest
1/3 of the wave spectrum. occasional wave height is the average of
the highest 1/10 of the wave spectrum.

.synopsis...a 30.3 inch high will weaken across the lower great 
lakes region today. a 29.4 inch low over the great plains tonight 
will advance northeast into the upper great lakes later tonight into 
tuesday morning, while pushing a warm front across the lake. the low 
will head northeast to james bay tuesday night sending a cold front 
across the lake. an inverted trough averaging 29.7 inch inverted 
trough is expected across the lower great lakes wednesday through 
wednesday night. the trough/low will track to the coast of new 
england through friday while also deepening to 29.5 inches.


loz062-272100-
lake ontario open waters from the niagara river to hamlin beach-
1002 am edt mon apr 27 2026

.this afternoon...east winds 5 to 15 knots. waves 1 to 3 feet. 
.tonight...east winds 15 to 20 knots becoming southeast 10 to
15 knots. waves 2 to 4 feet. 
.tuesday...southeast winds 10 to 15 knots becoming south 15 to
20 knots. showers. waves 2 to 4 feet. 
.tuesday night...southwest winds 15 to 20 knots becoming
northwest and diminishing to less than 10 knots overnight. a
chance of showers in the evening. waves 1 to 3 feet. 
.wednesday...north winds 5 to 15 knots becoming northwest 15 to
20 knots. showers. waves 1 foot or less building to 2 to 4 feet. 
.thursday...northwest winds 15 to 20 knots. a chance of rain
showers during the day. waves 2 to 4 feet building to 3 to
5 feet. 
.friday...northwest winds 15 to 20 knots. waves 3 to 6 feet. 

$$
fzus61 kbuf 271402
glflo 
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open lake forecast for lake ontario
national weather service buffalo ny
1002 am edt mon apr 27 2026

for waters beyond five nautical miles of shore on lake ontario

waves are the significant wave height - the average of the highest
1/3 of the wave spectrum. occasional wave height is the average of
the highest 1/10 of the wave spectrum.

.synopsis...a 30.3 inch high will weaken across the lower great 
lakes region today. a 29.4 inch low over the great plains tonight 
will advance northeast into the upper great lakes later tonight into 
tuesday morning, while pushing a warm front across the lake. the low 
will head northeast to james bay tuesday night sending a cold front 
across the lake. an inverted trough averaging 29.7 inch inverted 
trough is expected across the lower great lakes wednesday through 
wednesday night. the trough/low will track to the coast of new 
england through friday while also deepening to 29.5 inches.


loz063>065-272100-
lake ontario open waters from hamlin beach to the saint lawrence
river-
1002 am edt mon apr 27 2026

.this afternoon...southeast winds 10 knots or less becoming
northeast. waves 1 foot or less. 
.tonight...east winds 10 to 15 knots becoming southeast 15 to
20 knots. waves 1 to 3 feet. 
.tuesday...southeast winds 15 to 20 knots becoming south.
showers. waves 2 to 4 feet building to 3 to 5 feet. 
.tuesday night...south winds 15 to 20 knots becoming west 10 to
15 knots. showers likely in the evening, then a chance of showers
overnight. waves 3 to 5 feet subsiding to 1 to 3 feet. 
.wednesday...northwest winds 5 to 15 knots increasing to 15 to
20 knots. showers. waves 2 feet or less building to 2 to 4 feet. 
.thursday...northwest winds 15 to 25 knots. rain showers likely
during the day, then a chance of rain showers thursday night.
waves 3 to 5 feet building to 4 to 7 feet. waves occasionally
around 9 feet. 
.friday...northwest winds to 30 knots diminishing to 15 to
25 knots. a chance of rain showers. waves 6 to 9 feet subsiding
to 4 to 7 feet. waves occasionally around 11 feet. 

$$
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