Large Scale Characteristics of NARCCAP Generated Severe Weather Environments From Reanalysis and CCSM3 Simulations Using WRF

The North American Regional Climate Change Assessment Program (NARRCAP) seeks to investigate uncertainties in climate change projection. In order to ascertain such uncertainties, model climatology needs to be derived and evaluated for similarity to the current climate. The WRF model driven by the NCEP/NCAR Reanalysis 2 (R2) data set will be analyzed in terms of the larger scale dynamics including storm tracks and fronts, and also mesoscale processes such as the low level jet and the capping lid. Modeled low level moisture will be compared with observations and R2 to identify the downscaling ability of the model. This analysis will be compared to the distribution of CAPE and deep layer wind shear which are characteristic of the severe storm environment over North America. Comparisons will be made of the dynamics of the R2 vs CCSM3 current climate simulations, and CCSM3 current vs future climate simulations. The presentation will highlight model strengths and weaknesses in predicting the overall severe weather climate and forcing mechanisms of the central US.