National Weather Service Chicago/Romeoville IL
2:54 AM Thursday June 29.
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 29.5 inches over western lake superior will fill to 29.7 inches as it moves to east-central ontario by this evening. the low will drag a cold front across the lake and extend west across the lower great lakes into the central plains, while remaining nearly stationary. another low of 29.5 inches will develop tonight along the western end of the front. this low will slowly track east through the lower missouri valley to the ohio valley by saturday. low pressure of 29.8 inches is also expected to develop over south-central canada tonight. this low should slowly deepen as it moves into eastern ontario saturday with the trailing cold front pushing across the lake saturday night or sunday morning. high pressure of 30.1 inches is expected to build across the central plains sunday night and monday.