16-day (384-hour) forecasts from the 00Z run of the NCEP Global Ensemble Forecast System (GEFS) and Global Forecast System (GFS). Some of the products show forecasts every 12 hours, while others show forecasts every 24 hours.

The GFS data used here are on a 0.5° grid, while the GEFS data are on a 1.0° grid, though this makes little difference to the large-scale fields shown here.

Currently, the GEFS is not the same underlying model as the GFS, which was upgraded to the new FV3 dynamical core in 2019. A similar upgrade to the GEFS is planned for 2020.