Previously known as Northern Lightning, Sentry North is an annual exercise at Volk Field, Wisconsin first began as a handful of units training together in the early 2000s. In 2015 the exercise was expanded and has grown ever since. The concept of these exercises is to schedule and build only those training events that will directly benefit the participating flying squadrons. Basing the exercise format and objectives off of the established training plans and RAP Tasking Messages of the participating units ensures the relevancy of all training events. This customer-driven focus provides the driving force in shaping and scheduling each exercise as well as providing the core cadre of exercise participants.