NOAA proposes retiring NFCENS wave ensemble products

NOAA/NWS is seeking comments through May 14, 2026 on a proposal to stop disseminating all products from the Combined NCEP/FNMOC Wave Ensembles (NFCENS) system.

The notice says NFCENS is already in legacy status and is targeted for retirement as part of a broader effort to consolidate wave guidance.

What would be removed

If the proposal is finalized, NWS plans to stop dissemination of all NFCENS products through all transmission methods.

The associated EMC Verification System page for NFCENS would also be terminated:

https://emc.ncep.noaa.gov/users/verification/ocean_lake/nfcens/prod/

The notice does not give a final removal date. It is a comment solicitation, not a final Service Change Notice.

NOAA's suggested replacements

NOAA points users to two replacement paths:

• GEFS waves forecast data for probabilistic wave ensemble guidance
• NBM significant wave height, which NOAA says combines FNMOC data with additional wave ensemble model data

That is the main operational takeaway. NOAA is not presenting NFCENS as a model family to migrate forward. It is telling users to move wave workflows toward GEFS and NBM products instead.

Those two replacements are not identical. GEFS wave guidance is the better fit when the product needs ensemble spread or probability of exceeding a wave-height threshold. NBM significant wave height is the better fit when the product needs a blended gridded sea-state field from NOAA's post-processing system. If a legacy NFCENS workflow used the ensemble nature of the product, the GEFS side of the migration deserves special attention.

What this means for GribStream users

GribStream does not expose NFCENS as a model. We do support GEFS Wave Probabilities, which are useful for wave-height threshold risk, and NBM datasets such as NBM CONUS and NBM Oceanic, which include significant wave height guidance where NOAA publishes it.

So this proposal does not directly remove a GribStream dataset. It does matter indirectly, because NOAA is pointing users toward datasets that GribStream does serve.

For marine users, the migration direction is clear:

• use GEFS-derived wave probabilities when the workflow needs ensemble exceedance risk
• use NBM significant wave height when the workflow needs blended deterministic wave-height guidance
• treat NFCENS-specific archives and verification links as legacy dependencies that may disappear if the proposal is finalized

The notice does not say that GEFS wave guidance or NBM significant wave height is changing because of the NFCENS retirement. It says NFCENS is legacy and that users should migrate to those alternatives. If a future NOAA notice changes the underlying GEFS wave system or the NBM wave blend itself, that would be a separate model-method change to track.

If you still ingest NFCENS directly from NOAA, the comment window closes May 14, 2026. The listed feedback address is emc.products.feedback@noaa.gov.

For a GribStream migration, start by identifying whether the old workflow was using NFCENS as an ensemble risk product or as a single sea-state field:

• If it was ensemble risk, start with GEFS Wave Probabilities and map the threshold fields to the operational decision being made.
• If it was a deterministic/blended wave-height layer, start with NBM Oceanic or the relevant regional NBM grid and inspect HTSGW availability.
• If the workflow used NFCENS verification pages, plan to preserve any needed historical diagnostics before the EMC verification page disappears.

Sources

• NWS PNS 26-26, "Proposed Removal of All Products from the Combined NCEP/FNMOC Wave Ensembles (NFCENS) system" (Apr 14, 2026): https://www.weather.gov/media/notification/pdf_2026/pns26-26_NFCENS_Removal.pdf
• NWS notification index: https://www.weather.gov/notification/