An Updated High Resolution Hydrometeor Analysis System Using Radar and Other Data

For two decades the Center for Analysis and Prediction of Storms has developing and producing real-time high resolution analyses, nowcasts and forecasts. One element in the analysis product used in these systems is the analysis of hydrometeors, including clouds and precipitation-sized rain, snow, ice, and hail/graupel. Recently the hydrometeor analysis has been updated to accommodate new radar data and new cloud and precipitation microphysiscs schemes now used the CAPS Advanced Regional Prediction System (ARPS) and the Weather Research and Forecasting (WRF) forecast systems. The new radar data elements include the upgrade of the WSR-88D data to dual-polarization and addition of new radars that have been deployed for field projects, such as the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX-2), and for the Collaborative Adaptive Sensing of the Atmosphere (CASA) Dallas/Ft Worth Urban Testbed. Updates to hydrometeor assignment include direct or iterative inversion of radar reflectivity equations for the Lin 5-class Ice microphysics scheme, the WRF single-moment 6-class (WSM6) microphysics scheme, Milbrandt and Yau (MY) single-moment bulk microphysics scheme, MY double-moment bulk microphysics scheme, and MY triple-moment bulk microphysics scheme.

This work documents the current state of the hydrometeor analysis, including the radar pre-processing with quality control and remapping and updates to the hydrometeor assignment algorithms. Some examples of its use in static analysis and in short term forecasts utilizing the incremental analysis updating (IAU) data assimilation technique over the CASA Dallas/Ft Worth Urban Testbed are presented.