The GFS is a global spectral data assimilation and forecast model system. GFS forecasts are produced every six hours at 00, 06, 12 and 18 UTC. The GFS graphics are based on 70 km grid (T190) and are available at three hour increments out to 384 hours. The GFS also produces 27 km (T574) forecast out to 192 hours but these are not converted to graphic images. NCEP implemented major changes to GFS on July 28, 2010. The horizontal resolution increased from approximately 35 km (T382) to approximately 27km (T574) in both the analysis and forecast model. The vertical resolution is 64 layers, with a model top at 0.2 hPa. Additionally, a number of improvements have been made to the model’s ability to represent physical atmospheric processes. These improvements include an upgraded radiation and cloud package, upgraded specification of gravity wave drag, a higher resolution grid for hurricane relocation, an upgraded boundary layer scheme, the use of a higher resolution snow analysis, a new mass flux shallow convection scheme and an updated deep convection scheme.