GribStream Blog
GEFS v12.3.18 fixes missing wave-station ensemble stats on NOMADS
NWS says GEFS v12.3.18 restores missing spread and probability ensemble statistics in the NOMADS wave-station products, with the fix effective on or about February 24, 2026.
On February 13, 2026, NOAA/NWS issued SCN 26-15, announcing a GEFS v12.3.18 upgrade effective on or about February 24, 2026 beginning with the 12Z cycle.
This is a small change, but not a trivial one if you use NOAA's station-style wave products.
What the upgrade fixes
The SCN is very specific: spread and probability ensemble statistics were missing from the GEFS wave-station products. NOAA says v12.3.18 restores the full ensemble statistics set in that output.
The affected files live under the GEFS wave/station/ path on NOMADS and cover the standard 00/06/12/18 UTC cycles.
If you were using those station products before the upgrade, part of the ensemble picture was missing.
Why this matters
Wave-station products are useful precisely because they compress ensemble behavior into a station-style view that is easier to operationalize than full grids.
If the spread and probability pieces are missing, several common workflows break or degrade:
- quick station-level uncertainty checks
- threshold-based wave-risk monitoring
- regression tests that compare expected ensemble-stat fields over time
This is a data-quality fix, and the before/after date is clear.
Who should pay attention
This matters if you:
- validate gridded ensemble results against raw NOMADS wave-station products
- mix grid data with NOAA's station-style GEFS wave products in the same workflow
- archive or benchmark those NOMADS station products across the February 2026 boundary
In those cases, February 24, 2026 is a real before/after boundary worth annotating in QA and backtests.
Related reading
Sources
- NWS SCN 26-15 / GEFS v12.3.18 notice: https://www.weather.gov/media/notification/pdf_2026/scn26-15_GEFS_12.3.18.pdf