Ensembles Lessons
Table of Contents
CMC Automated Forecasting
The Canadian Meteorological Center (CMC) extended public forecasts to days 6 and 7 in 2009. To do so, the CMC used the Canadian Ensemble Forecast System (CEFS) to statistically generate forecasts for those days using a method similar to Model Output Statistics (MOS). This can be done because the deterministic Canadian Global Environmental Model (GEM) does not typically verify as well as the CEFS-generated statistical forecasts do. These ensemble-based forecasts also are usually better than forecasting climatology (see the graphic below), making them a valuable resource at these long lead times.
The forecaster has the option of adjusting the CEFS-based forecast if they deem it is warranted, based on pattern recognition or other forecaster expertise they hold. This option is rarely exercised, however.