The American GFS (Global Forecast System) model run in two parts: the first part (higher resolution) goes out to 192 hours with charts for every 6th hour. The second part (lower resolution) runs from 204 to 384 hours with charts for every 12th hour. In other words, first part goes to 8 days and second part goes to 16 days.
See Also
NAM vs HRRR. Compare the major regional weather models for North America - Windy.appForecast ModelsECMWF vs GFS. What’s the difference, and which weather model is more accurate - Windy.appWhat is AROME weather model and how it works - Windy.appThis numerical model is run four times a day, using 0, 6, 12 and 18 UTC data, and charts update begins at 3:30, 9:30, 15:30 and 21:30 UTC. First part resolution charts is about 100km (1º), and second part is about 250km (2.5º).
This model is run by National Oceanic and Atmospheric Administration (NOAA)
