National Weather Service Chicago/Romeoville IL
2:45 AM Thursday June 21.
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, low pressure of 29.7 inches over iowa this morning will slowly move to central illinois friday morning and then to near lake erie on saturday, as a weak ridge of high pressure remains stretched from the northern lakes region to new england. weak low pressure will move across ontario saturday and into quebec saturday night. a trailing cold front will move south across the region sunday night with high pressure of 30.2 inches moving across the great lakes on monday.