Research to Operations: Seasonal Predictability of Great Lakes Water Levels Resulting from Persistent Hydrometeorological Conditions

The coordinated Great Lakes water levels forecast is produced each month through efforts by both the U.S. Army Corps of Engineers and Environment and Climate Change Canada. The purpose of this forecast is to inform the commercial navigation industry, recreational boaters, hydropower generation agencies, and the general public about water level changes expected on the Great Lakes in the next 6 months. During the forecast process done by the U.S. Army Corps of Engineers, current basin conditions and hydroclimate forecasts are integrated into the water supply forecasts to each lake. However, there are challenges related to spatial inconsistencies in the data and forecasts produced by federal agencies on both sides of the border. There is also a lack of meteorological station data over the Great Lakes, which represent a very large portion of the basin area, relative to other large river basins. Despite efforts to use seasonal forecast guidance, water level forecast skill is limited by the ability to predict meteorological extremes and persistence of wet or dry conditions over several months to years. This presentation will emphasize the impacts of these challenges on predictability of seasonal changes in Great Lakes water levels.