FORECASTCONTEXT.COM · THE LARGE-SCALE STATE BEHIND THE FORECAST BRIEFINGMOTIONOUTLOOKMETHODSAPI☀ AUTO

FORECAST CONTEXT

DATA THROUGH 2026-10-12 · UPDATED 2026-10-13 11:02 UTC

ERA5 + GFS2.5°DAILY
BriefingTropics & oceansMJO & intraseasonal
BSISO1_amp

BSISO1 amplitude

√(PC1² + PC2²); above 1 = active. Meaningful May–October. — Lee et al. 2013 (Clim. Dyn. 40, 493)