NOAA DAFS In-Flight Icing Alaska

Description

DAFS IFI Alaska is NOAA/NCEP's Domestic Aviation Forecast System in-flight icing product for the Alaska domain. DAFS became operational as a standalone aviation forecast system on March 30, 2026, producing HRRR-derived aviation guidance through the Unified Post Processor. In GribStream, dafsifiak exposes the 3 km Alaska IFI feed mirrored from NOMADS.

The Alaska product carries the same IFI v2.0 hazard family as the CONUS feed: icing probability, icing severity, and supercooled large droplet potential. NOAA's official notes describe IFI v2.0 as a 60-level product from FL010 through FL300, with explicit liquid water content used in the core icing calculation and model supercooled rain treated as corresponding SLD potential. For Alaska, those fields are published on a 3 km polar stereographic grid and produced on three-hourly cycles with hourly forecast steps through 18 hours.

This dataset is useful for Alaska-focused aviation apps, route planning, briefing tools, and operational dashboards where coastal moisture, terrain, sparse observations, and rapidly changing freezing layers can make route-level icing awareness difficult. Use DAFS IFI CONUS for the contiguous United States and DAFS GTG for CONUS turbulence diagnostics. Pair DAFS IFI Alaska with HRRR or RAP when the workflow needs full winds, temperature, humidity, and cloud context around the icing guidance.

Detail

• Archive window: Last 3 days
• Product inventory: NCEP DAFS products
• Operational source: NOAA NOMADS DAFS
• Operational notice: NWS SCN 25-80
• Resolution: 3 km Alaska polar stereographic grid
• Forecast cadence and length: three-hourly cycles with hourly steps from 1 to 18 hours
• Vertical coverage: 60 levels every 500 ft from FL010 to FL300
• Core fields: icing probability, icing severity, and supercooled large droplet potential
• Companion datasets: DAFS IFI CONUS, DAFS GTG

Parameters