The technological progress over the last century allowed comprehensive measurements of the current conditions, while the advancements in computing power enabled large scale predictions of the Earth system, including atmosphere, land surface, cryosphere and hydrosphere. WMO facilitates the development and sharing of analysis and forecast products from advanced numerical prediction centres to all Members and international organizations to support their weather, climate, water and related environment services. 

Analysis is the best estimate of the current state of the Earth system, that are objectively analyzed using mathematical methods. Forecast is information on its future state, simulated on a computer using a numerical prediction model including physical and chemical processes.