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NOAA DAFS aviation icing and turbulence forecasts are now on GribStream

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dafsgtg dafsificonus dafsifiak hrrr rap

NOAA's short-range aviation icing and turbulence guidance is now available through GribStream for route screening, dispatch dashboards, and operational flight-planning tools.

GribStream now supports NOAA/NCEP's Domestic Aviation Forecast System (DAFS) aviation guidance as three API datasets:

DAFS is not another general-purpose weather model feed. It is a specialized aviation product family for turbulence and in-flight icing guidance. GribStream makes those NOAA operational products available through the same /timeseries, /runs, point, and grid API patterns used for HRRR, RAP, GFS, and the rest of the catalog.

What DAFS adds

DAFS v1.0 became operational on March 30, 2026. The system uses HRRR-derived fields and the Unified Post Processor to produce aviation diagnostics that used to live in older RAP-based workflows.

The first GribStream DAFS release focuses on the operational products with clear aviation value:

  • Graphical Turbulence Guidance (GTG) over CONUS, including eddy dissipation, clear-air turbulence, mountain-wave turbulence, convectively induced turbulence, and maximum turbulence guidance.
  • In-Flight Icing (IFI) over CONUS, with icing probability, icing severity, and supercooled large droplet potential.
  • In-Flight Icing (IFI) over Alaska, with the same icing fields on the Alaska 3 km grid.

The products are short-range by design. GTG runs from analysis/current conditions through 18 hours. IFI runs from 1 through 18 forecast hours. That makes DAFS best suited to operational aviation planning, route screening, dispatch dashboards, and pilot-briefing support where the latest forecast matters more than a long archive.

Dataset details

The DAFS feeds are split by product and grid so each dataset has a clear native geometry and parameter inventory.

dafsgtg is the CONUS turbulence product:

  • 3 km CONUS Lambert grid
  • hourly forecast steps from 0h to 18h
  • turbulence fields such as EDPARM, MXEDPRM, CATEDR, and MWTURB

dafsificonus is the CONUS icing product:

  • 3 km CONUS Lambert grid
  • hourly forecast steps from 1h to 18h
  • ICPRB, ICESEV, and SIPD

dafsifiak is the Alaska icing product:

  • 3 km Alaska polar stereographic grid
  • hourly forecast steps from 1h to 18h
  • ICPRB, ICESEV, and SIPD

How to use it

DAFS is most useful as an aviation hazard layer rather than a full atmospheric-state source. For example:

  • Use DAFS GTG to draw turbulence guidance at altitude along a route.
  • Use DAFS IFI CONUS or DAFS IFI Alaska to evaluate icing probability and severity by altitude.
  • Use HRRR or RAP beside DAFS when you need temperature, wind, moisture, pressure, or a Skew-T/log-P style profile.

That distinction matters. DAFS tells you where NOAA's aviation guidance sees icing or turbulence risk. HRRR and RAP provide the broader model state around that risk.

Why this matters

DAFS fills a gap left by the transition away from older RAP-based aviation products. NOAA's implementation notice moved the operational aviation icing and turbulence workflow to a standalone DAFS product family, while a separate NBM notice said the new DAFS IFI product is not planned to be hosted inside NBM because of domain differences.

For GribStream users, the practical outcome is simpler: aviation applications can now query DAFS directly instead of scraping NOMADS or looking for replacement fields in NBM. The API shape is the same as the rest of GribStream, so applications can focus on the aviation hazard layer rather than file handling.

Start here

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