dataset · Global
NOAA Global Ensemble Forecast System (GEFS)
The Global Ensemble Forecast System (GEFS), previously known as the GFS Global ENSemble (GENS), is a weather forecast model made up of 21 separate forecasts, or ensemble members. The National Centers for Environmental Prediction (NCEP) started the GEFS to address the nature of uncertainty in weather observations, which is used to initialize weather forecast models. The GEFS attempts to quantify the amount of uncertainty in a forecast by generating an ensemble of multiple forecasts, each minutely
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Licence: NOAA data disseminated through NODD are open to the public and can be used as desired. <br/> <br/> NOAA makes data openly available to ensure maximum use of our data, and to spur and encourage explora
Evidence quality: 47.5
Listed in aws-odr public catalogue API on 2026-10-16; relevance/value screened (haiku).
Metadata checked: 2026-10-14T13:20:00.000Z
What's in it
- Data offered docs-verified
- 21-member ensemble weather forecasts · forecasts out to 16 days
- Coverage docs-verified
- Global
- Update frequency docs-verified
- 4 times a day, every 6 hours starting at midnight
- Access docs-verified
- Free/open; no AWS account required (AWS CLI with --no-sign-request). NOAA open data licence: attribution requested for unaltered data, no endorsement implied
Useful for
- Use cases llm-inferred
- Ensemble forecast uncertainty envelopes for short-range rainfall and temperature context in flood risk assessments · Forecast-based weather window planning for site works and construction programmes · Ensemble spread as a sensitivity input for drainage strategy stress-testing alongside observed rainfall records
- Audience llm-inferred
- flood consultants · hydrologists · drainage engineers · civils engineers · GIS analysts
Limitations
- Constraints llm-inferred
- Global model, not UK-specific; no local downscaling provided · Forecast output only, not observational or historical data · Ensemble members are perturbed forecasts, so spread reflects model uncertainty rather than a calibrated probability · Attribution required for unaltered NOAA data; no implied endorsement
Evidence
- arn:aws:s3:::noaa-gefs-pds, arn:aws:sns:us-east-1:123901341784:NewGEFSObject
- https://registry.opendata.aws/noaa-gefs/
Check upstream coverage, uncertainty and licence before use. Station observations are not forecasts or design levels.