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
BriefingWeather regimesWeather regimes
WR_PNA4_AKR

Alaskan Ridge · PNA4

Projection index I_wr onto the Alaskan Ridge mean pattern (Pacific–North American regimes (Straus, 200 hPa)): standardized area-weighted projection of the normalised anomaly field. — Straus, Corti & Molteni 2007 (J. Climate 20, 2251)