Weather models are simulations of the atmosphere, or what a computer thinks the weather will do.
This is what meteorologists use on a daily basis to figure out what weather is to come.
Now models are run by computer alone, so the data that come out is only as good as the data that are put in.
Now there are different types of models.
Global models use the globe as their domain or the area that they cover.
Mesoscale models look at specific continents or regions within in a country.
The GFS stands for Global Forecasting System. This is the American model, which was created to forecast for the United States. It goes for 384 hours or 16 days.
The ECMWF, or the European model, was created to forecast for Europe but does a very good job of forecasting for the United States as well. It goes out 240 hours or 10 days.
The North American Model, or NAM, is a regional model that goes out 84 hours or 3.5 days. This is higher resolution, meaning it shows more detail.
The HRRR, or High-Resolution Rapid Refresh model, is used on the day of the event. What is unique about this model is that it is updated every hour. This is used for North America only and goes out 18 hours.
These models show a lot more detail and can show isolated storms on Futuretrack and can simulate thunderstorm development.
Models are not perfect. That is why there needs to a meteorologist present to interpret what the models cannot.
Models can often be wrong, and it takes a deeper understanding of meteorology to ensure the forecast is as accurate as it can be.