I live near Interstate 355, between 63rd and 75th Streets. Normally, all of the Southwest planes that I see are departures heading west, at various altitudes based on the ORD pattern.
On 8/22, I saw a strange pattern all afternoon and evening. I've been seeing Southwest planes heading northeast at somewhat lower altitudes what I see for MDW departures. They first appear to be in the ORD arrival pattern for Runway 4R, but they are too far east to be in that pattern, and I've noticed some of the planes eventually make gradual turns to the east.
Over the years, I've seen some unusual arrival patterns, say when there are strong thunderstorm cells interfering with normal arrival patterns. But the weather was generally good, with only high thin clouds.
Anyone know why MDW was running such a strange pattern?