The main weather feature across the Midwest late Friday was a ridge of high pressure from NW Wisconsin to the Ozarks, which provided comfortable temps and partly to mostly sunny skies. In Chicago the day produced 70% of possible sunshine. High pressure will shift east on Saturday, turning winds SE and signaling the onset of an influx of warm, progressively more humid air. Though Saturday will bring temps back to, or just above the seasonal norm, a more noticeable rise in heat and humidity is due to begin Sunday as SSW winds increase. Afternoon temps on both Sunday and Monday are expected to flirt with the 90-degree mark, though highs on Monday may run a few degrees lower due to an increase in cloud cover and greater likelihood of t-storm development. Cooler, much less humid air is forecast to return beginning Tuesday.