During the previous segment, the science of numerical weather prediction was introduced. Over the last several decades, scientists from around the world have created numerous forecasting models. One similarity between most of them is how they are initialized. Once initialized, the initial set of equations can begin to be solved. Then, the equations are solved hour-by-hour to represent how the atmosphere is expected to change with time. One of the key differences between the various forecasting models is that the equations they use to model the atmosphere vary, as well as the resolution of each model. Let's look into some of the more commonly used forecast models that meteorologists utilize on a daily basis.
The two main types of forecasting models that meteorologists utilize are global and regional. Global forecasting models are more holistic, as they look at the weather around the entire globe. Some of the commonly used global models are the GFS (Global Forecast System), ECMWF (European Center for Medium-Range Forecasts Model), and the GEM (Global Environmental Multiscale Model). The GFS is the American global model, while the ECMWF is run out of Great Britain. The GEM is based out of the Canadian Meteorological Centre. As you might expect, each country does have some pride over which model is superior. The ECMWF, also referred to as the European model, is often touted as the best global model. However, it does not always outperform the others. Therefore, meteorologists will oftentimes consult each of them and come up with a "compromise" solution between them when putting together a forecast.
The global forecast models generally produce forecasts for 10 to 16 days in the future, with the accuracy level falling off pretty quickly after 7 days out. Next week's segment looks at how "regional" forecast models differ from global ones.