National Weather Service Chicago/Romeoville IL
2:46 AM Sunday September 24.
waves are provided as a range of significant wave heights, which is the average of the highest 1/3 of the wave, along with the average height of the highest 10% of the waves which will occasionally be encountered. synopsis, high pressure of 30.2 inches centered south of lake erie will move little through the remainder of the weekend then gradually weaken early in the week. low pressure around 29.6 inches is expected to develop across the great lakes region on tuesday night and move northeast and deepen through midweek, with an associated cold front passing across the lake early wednesday.