Thunderstorms and Heavy Rain Across the Southern and Eastern US; Heat and Fire Weather Concerns in the West

Showers and thunderstorms are expected across the southern and eastern US this week, with heavy rain and localized flooding, particularly near the Gulf Coast. Monsoonal moisture will bring rain and potential flooding to parts of the Southwest. Heat and fire weather threats will continue to impact the West. Read More >

NZUS99 KBUF 302352
GLFLOT

Experimental Tabular Open Lake Forecast for Lake Ontario
National Weather Service Buffalo NY
752 PM EDT Mon Jun 30 2025

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 29.6 inch low will move from northwest Ontario
province today to east of Hudson Bay Tuesday while deepening to 29.2
inches. A cold front trailing this low will cross the lake Tuesday
morning. A 29.9 inch high will build into the Upper Great Lakes
Wednesday and Thursday. The high will then strengthen to 30.1 inches
as it centers over the lake on Friday.

LOZ062-010800-
Lake Ontario open waters from the Niagara River to Hamlin Beach-
752 PM EDT Mon Jun 30 2025

.Overnight...
Weather.............Mostly cloudy with showers likely with a chance
                              of thunderstorms, then mostly cloudy with
                              chance of showers and thunderstorms after
                              midnight.
Sfc winds...........Southeast 5 to 10 knots becoming south 10 to 15
                              knots after midnight.
100-ft winds........Southeast 10 to 15 knots becoming south 15 to
                              20 knots after midnight.
Sig waves...........1 to 3 feet.

.TUESDAY...
Weather.............Partly sunny.
Sfc winds...........Southwest 10 to 15 knots.
100-ft winds........Southwest 15 to 20 knots.
Sig waves...........2 to 4 feet.

.TUESDAY NIGHT...
Weather.............Mostly clear.
Sfc winds...........West 10 to 15 knots.
100-ft winds........West 15 to 20 knots.
Sig waves...........2 to 4 feet.

.WEDNESDAY...
Weather.............Sunny.
Sfc winds...........West 10 to 15 knots.
100-ft winds........Southwest 15 to 20 knots.
Sig waves...........2 to 4 feet.

.WEDNESDAY NIGHT...
Weather.............Partly cloudy, then mostly cloudy with chance
                              of showers and thunderstorms after midnight.
Sfc winds...........Southwest 10 to 15 knots.
100-ft winds........Southwest 15 to 20 knots.
Sig waves...........2 to 4 feet.

.FORECAST DAYS 3 THROUGH 5......
.THURSDAY...Chance of showers and thunderstorms in the morning.
West winds 10 to 15 knots. Waves 2 to 4 feet.
.FRIDAY...Northwest winds 5 to 10 knots. Waves 2 feet or less.
.SATURDAY...Chance of showers after midnight. Southwest winds
10 to 15 knots. Waves 2 to 4 feet.

$$

LOZ063>065-010800-
Lake Ontario open waters from Hamlin Beach to Sodus Bay-
Lake Ontario open waters from Sodus Bay to Mexico Bay-
Lake Ontario open waters from Mexico Bay to the Saint Lawrence
River-
752 PM EDT Mon Jun 30 2025

.Overnight...
Weather.............Mostly cloudy with showers likely with a chance
                              of thunderstorms, then mostly cloudy with
                              chance of showers and thunderstorms after
                              midnight.
Sfc winds...........South 10 to 15 knots.
100-ft winds........Southeast 15 to 20 knots.
Sig waves...........2 to 4 feet.

.TUESDAY...
Weather.............Mostly cloudy with chance of showers, then
                              partly sunny in the afternoon.
Sfc winds...........South 10 to 15 knots becoming southwest in the
                              afternoon.
100-ft winds........South 15 to 20 knots becoming southwest in the
                              afternoon.
Sig waves...........2 to 4 feet.

.TUESDAY NIGHT...
Weather.............Partly cloudy.
Sfc winds...........Southwest 10 to 15 knots.
100-ft winds........Southwest 15 to 20 knots.
Sig waves...........2 to 4 feet.

.WEDNESDAY...
Weather.............Sunny.
Sfc winds...........West 10 to 15 knots.
100-ft winds........West 15 to 20 knots.
Sig waves...........2 to 4 feet.

.WEDNESDAY NIGHT...
Weather.............Mostly clear, then chance of showers after
                              midnight.
Sfc winds...........Southwest 10 to 15 knots.
100-ft winds........Southwest 15 to 20 knots.
Sig waves...........2 to 4 feet.

.FORECAST DAYS 3 THROUGH 5......
.THURSDAY...Chance of showers. Southwest winds 10 to 15 knots.
Waves 2 to 4 feet.
.FRIDAY...Northwest winds 5 to 10 knots. Waves 1 to 3 feet.
.SATURDAY...Chance of showers after midnight. South winds 10 to
15 knots. Waves 2 to 4 feet.

$$

LOZ061-010800-
MAFOR 0103/
ONTARIO WEST 1/2 11400 13500 13610 11600. A chance of
thunderstorms late this evening, then a chance of showers and
thunderstorms overnight. Waves 1 to 2 feet.

ONTARIO EAST 1/2 11400 11410 12510 14610. A chance of showers and
thunderstorms overnight. A chance of showers Tuesday morning.
Waves 2 feet or less overnight. Waves 1 to 3 feet Tuesday and
Tuesday evening.

$$