GFS- Global Forecast System model. The GFS is a global model with a max resolution of 0.25º, or about 13 miles at our latitude.
The model forecasts in 1 hour intervals up to 120 hours, then every 3 hours up to 384 hours.
The GFS is updated four times daily, every 6 hours, starting at 00z (8 PM EDT). It takes NOAA supercomputers approximately 3:40 hours to compute its first 24 hours forecast for the entire globe.
Like all models, subsequent hourly forecasts become available incrementally.