Forecasts

Weekly Water Levels Forecast
Update for Friday July 23, 2010 (includes data summary)

Weather conditions: Most of the Great Lakes basin experienced partly cloudy weather through much of the week with temperatures slightly above seasonal averages. A low pressure storm system began moving through the basin from the west on Thursday bringing showers and thunderstorms which will continue into the weekend. As the low pressure system moves through the area, temperatures may drop briefly for Friday. Mixed periods of precipitation will return next week with temperatures remaining near seasonal averages. Most of the Great Lakes basin has received normal amounts of precipitation so far this month, with much higher than average amounts in a few locations.

Water Level Conditions: All of the Great Lakes continue to be below their levels of a year ago. The lakes are all currently 6 inches below last year's levels. Over the next month, the water level of Lake Superior is expected to rise 2 inches, while Lake Michigan-Huron is forecasted to remain near the same level over the next 30 days. The water level of Lake St. Clair is expected to decrease by 5 inches and Lakes Erie and Ontario are each expected to fall 4 inches over the next month. See the Daily Levels web page for more water level information.

Forecasted outflows / channel conditions: The outflows from Lake Superior into the St. Mary's River, Lake Huron into the St. Clair River, and Lake St. Clair into the Detroit River are forecasted to be below average during the month. Near average outflow is expected from Lake Erie into the Niagara River. The flow in the St. Lawrence River is forecasted to be below average throughout the month of July.

Alerts: Users of the Great Lakes, connecting channels and St. Lawrence River should keep informed of current conditions before undertaking any activities that could be affected by changing water levels. Mariners should utilize navigation charts and refer to current water level readings.

Other Forecasting
Also see: Huron-to-Erie Corridor Flows modeling product (requires Google Earth plug-in)