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Global Ensemble Forecast System

The Global Ensemble Forecast System (GEFS) is a weather model created by the National Centers for Environmental Prediction (NCEP) that generates 21 separate forecasts (ensemble members) to address underlying uncertainties in the input data such limited coverage, instruments or observing systems biases, and the limitations of the model itself. GEFS quantifies these uncertainties by generating multiple forecasts, which in turn produce a range of potential outcomes based on differences or perturbations applied to the data after it has been incorporated into the model. Each forecast compensates for a different set of uncertainties.

GEFS in the NOAA Big Data Program

The NOAA Big Data Program provides access to gridded 1.0°-resolution analysis and forecast data in a trailing 30-day window in the AWS Open Data Registry for GEFS.

GEFS Parameter Sets

GEFS Analysis

ModelGrid/ScalePeriod of RecordModel CycleOutput TimestepParameter Sets
GEFS, Control1.0°Trailing 30 days4/day: 00, 06, 12, 18UTC1/cyclepgrb2a, pgrb2b
GEFS, Perturbed (20 sets)1.0°Trailing 30 days4/day: 00, 06, 12, 18UTC1/cyclepgrb2a, pgrb2b

GEFS Forecasts

ModelGrid/ScalePeriod of RecordModel CycleOutput TimestepParameter Sets
GEFS, Control1.0°Trailing 30 days4/day: 00, 06, 12, 18UTC3-hourly, +000 to +384 hourspgrb2a, pgrb2b
GEFS, Perturbed (20 sets)1.0°Trailing 30 days4/day: 00, 06, 12, 18UTC3-hourly, +000 to +384pgrb2a, pgrb2b

GEFS Data on NCEI Servers

NCEI provides access to gridded GEFS output data on it’s servers. Many other forecast products are available at the NCEP GEFS home page.

Specifications

Model: 
GEFS, 21-Member
Grid/Scale | Period of RecordFilesModel CycleOutput TimestepData Access Links
003 (1º) | 01Jan2008–Present (approx. 1mo to present online)4/day: 00, 06, 12, 18UTC6-hourly: Anl, +000 to +384NCEI:  
002 (2.5º) | 01Jan2008–Present (approx. 1mo to present online)4/day: 00, 06, 12, 18UTC6-hourly: Anl, +000 to +384NCEI: 
003 (1º) | NCEP 7–day archive to present4/day: 00, 06, 12, 18UTC6-hourly: Anl, +000 to +384NCEP: 
HTTP