A Comparison of Mesoscale Analysis Systems Used for Severe Weather Forecasting

This project compares the relative performance of several mesoscale analysis systems with applications to severe weather forecasting, by exploring the ability of each to reproduce soundings collected during the Verification of the Origins of Rotation in Tornadoes Experiment 2 (VORTEX2). The first data set is comprised of hourly analyses and 1-h forecasts from the Rapid Update Cycle (RUC) model. The second data set is an hourly product of the Storm Prediction Center (SPC), which merges all available surface data with the latest RUC 1-h forecast of upper-air data to create a 3-dimensional description of the current state of the atmosphere. The third data set comes from a mesoscale ensemble forecast system—developed, in part, at the National Severe Storms Laboratory (NSSL)—that uses the Weather Research and Forecasting (WRF model) as its foundation. Nineteen model soundings from May and June of 2009 will be extracted from each dataset at the same geographical locations within the Great Plain region where the actual soundings were collected from pre-convective and near-storms environments during VORTEX2.

The ability of each analysis system to reproduce severe weather parameters calculated from the observed soundings is investigated. Parameters examined include convective available potential energy, planetary boundary layer height, and lifted condensation level. Errors such as root mean square difference and bias will be calculated for each of the parameters to verify the mesoscale analysis systems as well as display the potential use of an ensemble mesoscale analysis system for forecasting.