This was a routine Follow On Test & Evaluation (FOT&E, commonly called “Foot”) shot. It had been delayed for certain reasons so notification was shorter than normal. Also, they are all targeted at the test rage at the Kwajalein Atoll. Kwajalein has all the special radars and sensors to score the accuracy of the Re-entry Vehicle.
It seems to me that the press release on test launches always mention this location, even if it is common knowledge to everybody in the know. Is there another location where the missile from a test launch could head for?
I worked with a girl that grew up there as a child, (parents were civilians employed by the Air Force) - it was a story of a fascinating childhood.