Pacific–North American (RPCA daily)

CPC-method rotated-PCA Pacific–North American pattern rebuilt from ERA5 500-hPa height, daily least-squares fit on patterns interpolated to the day. Positive: high near Hawaii and over the intermountain West, lows south of the Aleutians and over the south-east US. — Barnston & Livezey 1987; NOAA CPC