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

🇺🇸 N551AS - Boeing 737NG 890/W - Alaska Airlines ASA455/AS455, San Francisco (SFO) to Washington Dulles (IAD) - 4.6 mi away @ 39150 ft, heading E at 513 mph. Spotted for first time! [03:04:00 AM CDT] #A70333 #N551AS #B738 #ALASKA #ASA455 #AS455 #ADSB #ADSBbot