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

🇺🇸 N428AS - Boeing 737NG 990ER/W - Alaska Airlines ASA291/AS291 (SEA-STL-SEA) - 4.5 mi away @ 8800 ft, heading ESE at 316 mph. Spotted 5x before! [06:40:54 PM CDT] #A51968 #N428AS #B739 #ALASKA #ASA291 #AS291 #Landing #ADSB #ADSBbot