Major advances in radar technology have paved the way for the development of an Airborne Phased Array Radar (APAR) system that can provide unprecedented detailed observations of the dynamics and microphysics of high-impact storms such as hurricanes and mesoscale convective systems. The APAR currently under design by NCAR/EOL consists of four removable C-band Active Electronically Scanned Arrays (AESA) mounted on the top, both sides, and the cargo door of the NSF/NCAR C-130 aircraft.