WHyMSIE (Westcoast & Heartland Hyperspectral Microwave Sensor Intensive Experiment) is the very first step forward towards an integrated, intelligent, and affordable PBL (Planetary Boundary Level) observing system of systems. It will bring together multiple observing nodes – i.e., space, suborbital, and ground – from passive and active sensors to enable a comprehensive and coherent picture of essential PBL thermodynamic variables such as temperature, water vapor, height, and hydrometeors to provide new understanding of the PBL that is not possible with any single sensor, observational approach, or scale.