NOAA Global Ensemble Forecast System (GEFS) Re-forecast

climate meteorological sustainability weather


NOAA has generated a multi-decadal reanalysis and reforecast data set to accompany the next-generation version of its ensemble prediction system, the Global Ensemble Forecast System, version 12 (GEFSv12). Accompanying the real-time forecasts are “reforecasts” of the weather, that is, retrospective forecasts spanning the period 2000-2019. These reforecasts are not as numerous as the real-time data; they were generated only once per day, from 00 UTC initial conditions, and only 5 members were provided, with the following exception. Once weekly, an 11-member reforecast was generated, and these extend in lead time to +35 days. Browse the bucket at

Update Frequency

Re-forecasts do not adhere to an update frequency.


Open Data. There are no restrictions on the use of this data.


Managed By

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For any data delivery issues or any questions in general, please contact the NOAA Big Data Program Team at:

Usage Examples


Resources on AWS

  • Description
    GEFS Re-forecast in Grib2 Format
    Resource type
    S3 Bucket
    Amazon Resource Name (ARN)
    AWS Region
    AWS CLI Access (No AWS account required)
    aws s3 ls s3://noaa-gefs-retrospective/ --no-sign-request

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