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FORECAST CONTEXT

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

ERA5 + GFS2.5°DAILY
BriefingWeather regimesWeather regimes
WR_NA4V_AL

Arctic Low · NA4V

Projection index I_wr onto the Arctic Low mean pattern (North American winter regimes (Vigaud)): standardized area-weighted projection of the normalised anomaly field. — Vigaud, Robertson & Tippett 2018 (MWR 146, 2559)