Improving Weather Observations with a Transportable Radar in Mountainous Areas: Mineral County, Colorado

Precipitation monitoring in mountainous areas is a challenge with a combination of low radar coverage from operational networks, mountain blockage and specific vertical structure of precipitation. Warm rain and precipitation enhanced close to the surface are likely to develop with specific microphysics driven by the environment and collision-calescence processes in the liquid phase, which makes usual Z-R relationship inaccurate. They are likely underestimated and because of the steep slopes of mountainous terrain, flash floods and landslides can easily develop unnoticed. In Fall 2014 a transportable radar was deployed at the Lobo Overlook of the Mineral county, Colorado, to assess the added values to the operational practice of deploying a polarimetric radar in a mountainous area. This region is one of the numerous areas in the Rocky Mountains where the operational weather radar network WSR-88D network does not provide sufficient weather coverage due to blockages. The deployment was coordinated with the forecasters and local emergency managers to support accurate predictions and issuance of weather warnings for flash floods and landslides. Several datasets were collected to demonstrate the added values of deploying a small weather radar in the Mineral county. They highlight the needs of gap-filling radars to correctly sample the vertical structure of precipitation and to analyze the specific microphysics in mountainous regions. Several cases are provided will be presented for illustration including warm rain processes.