GribStream Blog
Full GEFS ensemble members now available
GribStream now serves all GEFS ensemble members, not just the mean, enabling true probabilistic workflows.
On June 21, 2025, we enabled access to all GEFS ensemble members, not just the mean.
What is new
GEFS Atmos runs the GFS 31 times per cycle: 30 perturbed members plus one control. You can now pull every member on the 0.25 deg global grid with four daily cycles (00/06/12/18 UTC) and lead times out to 240 hours.
Why it matters
Full-member access unlocks real probabilistic workflows:
- Compute spread and percentiles instead of relying on the mean.
- Build probability of exceedance for thresholds.
- Identify member agreement to gauge confidence windows.
Usage tips
- Use the
membersparameter to request a subset when you want to control volume. - Combine with expressions and filters to return only events of interest.