Influence of the Polar‐Eurasia Pattern on Interannual Variations in Extratropical Transition of Western North Pacific Tropical Cyclones

Abstract This study investigates climate drivers influencing interannual changes in the extratropical transition (ET) of western North Pacific tropical cyclones (TCs) during July–October from 1979 to 2024. We find a pronounced relationship between the fraction of TCs experiencing ET (ETTCs) to all TCs and the Polar‐Eurasia (POL) pattern. There is a significantly lower ETTC fraction in positive POL years relative to negative POL years. This lower ETTC fraction can be linked to significant decreases in the 700‐hPa maximum Eady growth rate spanning 30°–40°N. Poleward‐moving TCs have to travel for a longer distance to reach the region favorable for baroclinic development, reducing their ET probability. There are only slight changes in maximum potential intensity over the basin. The POL‐induced changes in atmospheric conditions are further explained by strong (weak) southward propagation of wave energy originating from the polar regions at middle (lower) levels.