This forecast of lake-wide average water levels for the next 6 months is issued jointly by the U.S. Army Corps of Engineers (Detroit District) and Environment Canada's Great Lakes - St. Lawrence Regulation Office. Checking the 'Current coordinated 0-6 month out forecasts' box displays the official water level forecast for the basin. The dark red bars indicate the 90% confidence interval for the forecasts. These agencies combine efforts each month to produce one 'Coordinated' common forecast for each of the Great Lakes. Their monthly forecast bulletins are available on their respective websites:
U.S. Army Corps of Engineers Six-Month Forecast Bulletin
Canadian Hydrographic Service Forecast Bulletin
The archived water level forecasts produced by the U.S. Army Corps of Engineers and Environment Canada start in 1994. Forecast probability bands for both 3-month (pink) and 6-month (brown) forecasts can be shown on the dashboard by checking the appropriate menu boxes. The colored bands show the 90% probability intervals for the month's mean water level. Projected levels are expected to be within these bands approximately 90% of the time, whereas levels both above or below the band can each be expected approximately 5% of the time. Forecasts are archived in order to analyze and improve model performance.