227
FZUS61 KBUF 210803
GLFLO

Open Lake Forecast for Lake Ontario
National Weather Service Buffalo NY
402 AM EDT Tue Jul 21 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 29.4 inch low will be near James Bay with multiple frontal
boundaries crossing the lake through tonight. A secondary cold front
will cross the lake Wednesday, with a 30.1 inch high building across
the lower Great Lakes region Wednesday night through Friday. The
high will move off the east coast Saturday.

LOZ062-211500-
Lake Ontario open waters from the Niagara River to Hamlin Beach-
402 AM EDT Tue Jul 21 2026

.TODAY...South winds 15 to 25 knots becoming southwest. Showers
with a chance of thunderstorms. Some thunderstorms may produce
gusty winds from late morning on. Waves 1 to 3 feet building to
3 to 5 feet.
.TONIGHT...Southwest winds 15 to 20 knots becoming west. Showers
with a chance of thunderstorms early, then a chance of showers
and thunderstorms late in the evening. Some thunderstorms may
produce gusty winds in the evening. Waves 3 to 5 feet.
.WEDNESDAY...West winds 15 to 25 knots. Waves 3 to 6 feet
building to 4 to 7 feet. Waves occasionally around 9 feet.
.WEDNESDAY NIGHT...Northwest winds 15 to 20 knots becoming west
10 to 15 knots. Waves 3 to 6 feet subsiding to 1 to 3 feet.
.THURSDAY...West winds 10 knots or less becoming southwest. Waves
2 feet or less.
.FRIDAY...South winds 10 knots or less becoming southeast. Waves
1 foot or less.
.SATURDAY...South winds 10 knots or less becoming southwest.
Waves 1 foot or less.

Winds and waves higher in and near thunderstorms.

$$

LOZ063>065-211500-
Lake Ontario open waters from Hamlin Beach to the Saint Lawrence
River-
402 AM EDT Tue Jul 21 2026

.TODAY...South winds 15 to 20 knots. Showers with a chance of
thunderstorms late this morning. Showers with thunderstorms
likely this afternoon. Some thunderstorms may produce gusty winds
from late morning on. Waves 2 to 4 feet building to 3 to 5 feet,
then subsiding to 2 to 4 feet.
.TONIGHT...South winds 10 to 15 knots becoming west 15 to
20 knots. Showers likely with a chance of thunderstorms in the
evening, then a chance of showers and thunderstorms after
midnight. A chance of showers late. Some thunderstorms may
produce gusty winds in the evening. Waves 2 to 4 feet building to
3 to 6 feet.
.WEDNESDAY...West winds 15 to 25 knots. Waves 5 to 8 feet. Waves
occasionally around 10 feet.
.WEDNESDAY NIGHT...West winds 15 to 25 knots diminishing to 10 to
15 knots. Waves 5 to 8 feet subsiding to 2 to 4 feet. Waves
occasionally around 10 feet.
.THURSDAY...West winds 5 to 15 knots becoming southwest less than
10 knots. Waves 1 to 3 feet subsiding to 1 foot or less.
.FRIDAY...South winds 10 knots or less. Waves 1 foot or less.
.SATURDAY...South winds 10 knots or less. Waves 1 foot or less.

Winds and waves higher in and near thunderstorms.

$$

LOZ061-211500-
MAFOR 2109/
ONTARIO WEST 1/2 11410 11426 12536 11526 11610 12620. A chance of
thunderstorms today and this evening. Waves 1 to 3 feet building
to 3 to 5 feet today. Waves 3 to 5 feet tonight.

ONTARIO EAST 1/2 11420 13426 11410 11516 11510 11620. A chance of
thunderstorms today and this evening. Waves 1 to 3 feet building
to 3 to 5 feet, then subsiding to 2 to 4 feet today. Waves 1 to 3
feet building to 3 to 5 feet tonight.

$$