Global Forecast System (GFS)

Description

GFS (Global Forecast System) is NOAA/NCEP’s primary global numerical weather prediction model. It is a tightly coupled system integrating four model components—atmosphere, ocean, land/soil, and sea ice—that work together to simulate Earth’s weather in three dimensions. The atmospheric component uses the FV3 dynamical core running at ~0.25° (~28 km) resolution, with forecasts generated four times daily. The ocean, land, and sea ice models update the surface and boundary conditions to enable consistent long-range simulation across the coupled climate-weather interface.:contentReference[oaicite:0]{index=0}

GFS runs globally with ~127 vertical levels up to the mesopause and produces high-temporal-resolution outputs—hourly forecasts up to 120 h, 3-hourly to day 10, and 12-hourly out to day 16 (384 h)—while transitioning to coarser spatial resolution in extended range.:contentReference[oaicite:1]{index=1} The atmosphere model is supported by a variational analysis system (GDAS/GFS Analysis) that assimilates satellite, radar, radiosonde, surface, and other observations into the initial condition.

GFS serves as the backbone for many downstream products: it powers the GEFS ensemble (and its wave, chemistry, and aerosol variants), supports seasonal to subseasonal systems like the CFS, and inform regional models like HRRR and RAP through boundary conditions.

GFS is widely used in global forecasting and medium-range outlooks, aviation routing, maritime navigation, environmental modeling, agricultural planning, and climate downscaling. Its long-term runs make it the default reference model for global weather outlooks and historical analysis in machine learning and operational workflows.

Detail

• Product page: NCEI Global Forecast System
• Key Features:
  • Coupled atmosphere-ocean-land-sea-ice system (GFS, MOM, land model, ice).
  • FV3 dynamical core, ~0.25° horizontal resolution, ~127 vertical levels.
  • Forecast output: hourly to 120 h; 3-hourly thereafter up to 384 h (~16 days).
  • Feeds into GEFS, CFS, HRRR boundary forcings, and global reanalysis workflows.
• Resolution: ~0.25° (~28 km) globally.
• Temporal Coverage: Four cycles per day (00, 06, 12, 18 UTC); forecasts up to 384 h ahead.
• Primary Use Cases: Global weather outlooks, aviation and marine routing, climate downscaling, machine learning labels, global regridding.

Parameters