NOMADS updates (RRFS, etc.)

[blaylockbk]

Some things probably need to take note of in this notice...

NOMADS users,
Please review the list of recent and upcoming changes to data availability on NOMADS.

National Blend of Models v 5.0 is operational as of May 5. Service Change Notice
https://www.weather.gov/media/notification/pdf_2026/scn26-24NBM_V5.0.pdf

RRFS and REFS will begin parallel feed around June 9 Service Change Notice
https://www.weather.gov/media/notification/pdf_2026/scn26-48_RRFS_and_REFS_Implementation.pdf

NAM, HiresW, HREF, SREF, NAM MOS ENDS Aug 31 Service Change Notice
https://www.weather.gov/media/notification/pdf_2026/scn26-47_Retirement_of_NAM_SREF_HREF_HiresW_NAM_MOS.pdf

Please review the Change notices above! These contain all of the most up-to-date technical details and will be updated with any changes as implementation gets closer.

Thanks

Margaret Curtis
HPC Dataflow Team Lead
NWS Central Operations
margaret.curtis@noaa.gov

[blaylockbk]

RRFS

https://www.weather.gov/media/notification/pdf_2026/SCN26-048-Updated_RRFS_and_REFS_Implementation.aaa.pdf

Subject: UPDATED: Implementation of the Rapid Refresh Forecast System
(RRFS) and RRFS Ensemble Forecast System (REFS): Effective Aug 31, 2026
Updated to reflect a change to the parallel data feed; now available on
July 7, 2026.
Effective on or about Aug 31, 2026, beginning with the 1200 Coordinated
Universal Time (UTC) run, the National Centers for Environmental
Prediction (NCEP) will implement two new modeling systems, the Rapid
Refresh Forecast System (RRFS) and RRFS Ensemble Forecast System (REFS).
The RRFS and REFS will replace NAM, HREF, SREF, and HiresW.