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GEFS·dataset

Many-scenario global weather forecast (NOAA)

NOAA Global Ensemble Forecast System (GEFS)
atmosphere NOAA NOAA active
In plain English

What it measures. A weather forecast made of 21 slightly different runs, which together show the range of possible outcomes and how confident the forecast is.

How it's made. Produced by NOAA's National Centers for Environmental Prediction by nudging the starting observations in small ways to create an ensemble of forecasts.

How & where you'd use it. Used to gauge forecast uncertainty and the odds of different weather, with global coverage four times a day out to 16 days.

What's measured

aws-pdsagricultureclimatemeteorologicalweather

Coverage & cadence

  • Time span— → ongoing

What you can do with it

  • Map air pollutants — NO₂, aerosols, ozone
  • Track greenhouse gases and Earth's energy budget
  • Feed weather and air-quality analysis
Official description

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 different, or perturbed, from the original observations. With global coverage, GEFS is produced four times a day with weather forecasts going out to 16 days.

Get the data

noaa_access.py
# NOAA Open Data on AWS — public S3, no login
import s3fs

fs = s3fs.S3FileSystem(anon=True)
# find this dataset's bucket in the docs link in the sidebar, then:
# files = fs.ls("noaa-<bucket>/...")
# open NetCDF/GRIB with xarray, COGs with rioxarray
NOAA Open Data is on public AWS S3 — no login at all (anonymous access).