GEM LAM Convective Forecasts: How Can they be used in an Operational Forecast Environment?

The Canadian GEM-LAM is a nested local area model with a horizontal resolution of 2.5 km. The GEM-LAM window for western Canada covers southern BC and southern Alberta. During the summers of 2006 and 2007, a systematic evaluation of the GEM-LAM forecasts of convection over Alberta was carried out in Edmonton. Conclusions were drawn on the utility of GEM-LAM as a tool in operational summer convective forecasting. It was found that while the timing of convective initiation over the foothills was modeled reasonably well; downstream, the subsequent convective development pattern was unreliable. In March 2008, the Milbrandt-Yau condensation scheme was implemented in the model. In order to evaluate any improvements in GEM-LAM performance, eight case studies of convective events over Alberta during the summer of 2009 were completed. This presentation will evaluate the potential benefits of utilizing the GEM-LAM on the forecast desk in convective situations. Various aspects of convection, including convective initiation, convective evolution, convergence zones and dewpoint temperatures, will be examined.