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NWPS v1.5 proposal adds GRIB2 runup, rip-current, and inlet-current products

NWS proposed NWPS v1.5.0 with unstructured meshes, expanded runup and rip-current guidance, and additional GRIB2 fields for coastal wave workflows.

NOAA/NWS issued PNS 26-10 on February 6, 2026, soliciting comments through March 16, 2026 on a proposed Nearshore Wave Prediction System (NWPS) v1.5.0 upgrade.

This qualifies as GribStream-relevant because the notice explicitly adds fields to NWPS GRIB2 files on NOMADS.

Proposed model and domain changes

The proposal moves 12 WFO domains from nested regular grids to variable-resolution unstructured meshes. The listed offices are:

  • Western Region: LOX, MTR, EKA, MFR, PQR
  • Southern Region: BRO, LCH, LIX
  • Alaska Region: AJK, AER, AFG
  • Eastern Region: LWX

NWPS v1.5.0 would also expand:

  • wave runup guidance for erosion and overwash
  • rip-current guidance
  • high-resolution depth-averaged currents for 11 Western Region inlets, ingested from Global STOFS v3.1 to model wave-current interaction

GRIB2 product additions

NOAA says the upgrade does not move, rename, or remove existing NWPS forecast products on NOMADS.

It does add fields to GRIB2 products. For listed Western Region and Southern Region WFOs, these fields would be included in the CG1 GRIB2 file:

${WFO}.nwps_CG1_${PDY}_${CC}.grib2

Added fields include:

  • erosion occurrence probability (EROSNP)
  • overwash occurrence probability (OWASHP)
  • total water level accounting for tide, wind, and waves (TWLWAV)
  • total water level increase due to waves (RUNUP)
  • mean increase in water level due to waves (SETUP)
  • time-varying increase in water level due to waves (SWASH)
  • total water level above dune toe (TWLDT)
  • total water level above dune crest (TWLDC)
  • rip-current probability (RIPCOP)

For EKA, NOAA also proposes an additional nested CG2 grid for high-resolution wave-current interaction at Humboldt Bay Spit, with fields including significant wave height, primary wave direction and period, swell height, wind, sea-level deviation, and current direction/speed.

The existing EKA CG2 wind-only grid would be renamed to CG3.

What this means for GribStream users

GribStream does not currently expose NWPS as a model. The proposal still matters under the NOMADS-GRIB roadmap: it adds coastal hazard variables to GRIB2 files already structured for NOMADS delivery.

For future mirroring, NWPS is a different kind of marine dataset than global wave guidance. It is local-office and nearshore oriented, with fields aimed at runup, overwash, rip currents, and inlet wave-current interaction rather than broad offshore wave probability.

If NOAA finalizes NWPS v1.5.0, the main ingest-sensitive changes are the new GRIB2 fields and the EKA CG2/CG3 grid naming change.

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