GFS- Global Forecast System model. A Global model with a resolution of 0.25º or about 19 kilometers. 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 00z (8 PM EDT). It takes NOAA supercomputers approximately 3:40 hours to compute its first 24 hours forecast. Like all models, subsequent hourly forecasts become available incrementally.