GRAF refers to an AI-based global weather forecasting model developed by NOAA (GSL) and collaborators, and the name stands for:
GRAF = Global Regression AI Forecast model
It’s part of the new generation of machine-learning weather models, similar in spirit to GraphCast or Pangu, but developed inside the NOAA ecosystem.
What is the GRAF model?
GRAF is a pure machine-learning global forecast model that:
Learns atmospheric evolution from historical reanalysis data
Produces global forecasts without explicitly solving physical equations
Uses regression-based deep learning to predict future atmospheric states
Think of it as:
“AI learning how the atmosphere usually evolves, then extrapolating forward.”
Key characteristics
Global coverage
AI / ML-based (no traditional physics core)
Predicts large-scale fields (e.g., 500 mb heights, winds, temps, MSLP)
Extremely fast compared to physics models
Designed primarily for pattern and flow prediction
What GRAF is good at
Large-scale synoptic pattern recognition
Jet stream placement
Ridge / trough evolution
Medium-range guidance (Days 3–7)
This makes it useful for:
Pattern forecasting
Ensemble support
Early signal detection
What GRAF is NOT good at
Precipitation amounts
Snowfall totals
Precipitation type
Mesoscale features (banding, fronts)
Boundary-layer processes