Great Lakes Forecast
Issued by NWS

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754
FZUS61 KBUF 172003
GLFLO

Open Lake Forecast for Lake Ontario
National Weather Service Buffalo NY
403 PM EDT Fri Jul 17 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 30.0 inch ridge of high pressure will slide east of the Lake this
evening to the Atlantic shoreline and in its wake a warm front will
lift northeastward across the Lake tonight through tomorrow morning.
Following this warm front a cold front will slice across the Lake
Saturday afternoon and evening with this front attached to a 29.4
inch area of low pressure crossing southern Canada. A 30.0 inch area
of high pressure will build across the Great Lakes region from west
to east Sunday into Monday, followed by another cold front Tuesday
night with this front attached to a 29.5 inch area of low pressure
near James Bay. A secondary cold front will cross the Lake
Wednesday.

LOZ062-180300-
Lake Ontario open waters from the Niagara River to Hamlin Beach-
403 PM EDT Fri Jul 17 2026

.TONIGHT...Southeast winds 5 to 15 knots becoming south. Smoke
through the early overnight. Waves 1 foot or less.
.SATURDAY...Southwest winds 15 to 20 knots becoming west. Showers
likely early, then a chance of showers and thunderstorms late in
the morning. Showers with a chance of thunderstorms in the
afternoon. Some thunderstorms may produce gusty winds in the
afternoon. Waves 1 to 3 feet building to 3 to 6 feet.
.SATURDAY NIGHT...West winds 15 to 20 knots becoming north.
Showers likely in the evening. Waves 3 to 5 feet.
.SUNDAY...North winds 5 to 15 knots becoming west. Waves 1 to
3 feet.
.SUNDAY NIGHT...West winds 10 knots or less becoming southwest.
Waves 1 foot or less.
.MONDAY...Southwest winds 5 to 15 knots becoming south 15 to
20 knots. Showers likely Monday night. Waves 1 to 3 feet.
.TUESDAY...South winds 15 to 25 knots becoming west. Showers with
a chance of thunderstorms. Waves 3 to 5 feet.
.WEDNESDAY...West winds 15 to 20 knots. A chance of showers
during the day. Waves 3 to 6 feet.

Winds and waves higher in and near thunderstorms.

$$

LOZ063>065-180300-
Lake Ontario open waters from Hamlin Beach to the Saint Lawrence
River-
403 PM EDT Fri Jul 17 2026

.TONIGHT...Southeast winds 5 to 15 knots becoming south 15 to
20 knots. Areas of smoke this evening. Waves 1 foot or less
building to 1 to 3 feet.
.SATURDAY...South winds 15 to 25 knots becoming west. Showers in
the morning, then showers with a chance of thunderstorms in the
afternoon. Some thunderstorms may produce gusty winds in the
afternoon. Waves 2 to 4 feet building to 3 to 6 feet.
.SATURDAY NIGHT...West winds 15 to 25 knots becoming northwest.
Showers with a chance of thunderstorms in the evening. Some
thunderstorms may produce gusty winds in the evening. Waves 3 to
6 feet building to 4 to 7 feet, then subsiding to 3 to 6 feet.
Waves occasionally around 9 feet.
.SUNDAY...Northwest winds 15 to 20 knots becoming west 10 to
15 knots. Waves 3 to 5 feet subsiding to 1 to 3 feet.
.SUNDAY NIGHT...West winds 5 to 15 knots. Waves 1 to 3 feet.
.MONDAY...Southwest winds 5 to 15 knots becoming south 15 to
20 knots. A chance of showers Monday night. Waves 2 feet or less
building to 2 to 4 feet.
.TUESDAY...South winds 15 to 25 knots becoming west. Showers with
a chance of thunderstorms. Waves 3 to 5 feet building to 3 to
6 feet.
.WEDNESDAY...West winds 15 to 25 knots. Showers likely during the
day, then a chance of showers Wednesday night. Waves 4 to 7 feet
subsiding to 3 to 6 feet. Waves occasionally around 9 feet.

Winds and waves higher in and near thunderstorms.

$$

LOZ061-180300-
MAFOR 1721/
ONTARIO WEST 1/2 13300 11310 11410 12520 11536. A chance of
thunderstorms Saturday afternoon. Waves 2 feet or less tonight.
Waves 1 to 3 feet building to 3 to 6 feet Saturday.

ONTARIO EAST 1/2 12300 11400 11410 11420 11426 11520 11526. A
chance of thunderstorms Saturday afternoon. Waves 1 foot or less
building to 1 to 3 feet tonight. Waves 2 to 4 feet building to 3
to 6 feet Saturday.

$$