Dual-Model Predictive Engine — ATLAS runs the NOAA supercomputer output (HRRR + NAM + GFS hourly blend via NWS) and the ECMWF IFS European model (0.25° via Open-Meteo) independently for each airport. Predicted AAR uses FAA ASPM-calibrated degradation curves: ceiling, visibility, wind, and precip probability. HIGH confidence = models agree · MEDIUM = off by one category · LOW = diverge 2+ categories (treat as directional only). When models disagree, ATLAS uses the conservative (worse) category.