Map of the St. Louis area showing the position and track of the aircraft described in the post.

🇺🇸 N8312C - Boeing 737NG 8H4/W - Southwest Airlines SWA4621/WN4621, William P Hobby (HOU) to Chicago Midway (MDW) - 4.3 mi away @ 36000 ft, heading NNE at 554 mph. Spotted 86x before. [10:49:15 PM CDT] #AB5EB2 #N8312C #B738 #SOUTHWEST #SWA4621 #WN4621 #ADSB #ADSBbot