We propose ground-based monitoring system for atmospheric water vapor based on wide-range spectra at 20 – 30 GHz and 50 – 60 GHz ranges. It observes in these microwave range and estimates the thermodynamic environments in the atmosphere. These information can determine short-term forecasting and now casting of severe storms. Our system can catch rapid increase of water vapor before clouds generation. We employ cold receiver system to achieve a system temperature below the atmospheric radiations. We will present overview of the system, including status of development, and results of long-term monitoring in outside.