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

🇺🇸 N812AK - BOEING 737 MAX 8 - ALASKA AIRLINES INC ASA5/AS5, Ronald Reagan Washington Ntl (DCA) to Los Angeles (LAX) - 4.5 mi away @ 37575 ft, heading W at 508 mph. Spotted for first time! [09:47:06 AM CDT] #AB10D4 #N812AK #B38M #ASA5 #AS5 #ADSB #ADSBbot