TheClimate Forecast System orcoupled forecast system (CFS) is a medium to long rangenumerical weather prediction and aclimate model run by theNational Centers for Environmental Prediction (NCEP) to bridge weather and climate timescales.[1] Version 2 became operational as CFSv2 in 2011.[2]
CFSv2 is run once daily at NCEP, at multiple time scales. The medium-range model forecasts in one-week intervals out to four weeks, while the longer-range scale forecasts on three-monthmoving averages out some nine months. The shorter scale has some overlap with theGlobal Forecast System,NAVGEM andFIM models (among several other medium-range models) that the US government runs for operational forecast purposes.
"Coupled" refers to the fact that the model couplesatmospheric to oceanic modeling. Its forecasts are derived from a 16-memberensemble, with each member initialized on a lead of several days of conditions. The CFSv2 offers output that can be masked to suppress forecasts made with insufficient skill.[clarification needed]
Among the variables made available to the public include precipitation and surface temperature (both of which are available both on a global spatial scale and a continental one), winds at 200 and 850hectopascals (hPa), and heights at 500 hPa (all of which are available only at the global or hemispheric scale). Output is rendered as deviation from normal.