Summertime Convection Jump over the Subtropical Western North Pacific and its Relation to Rossby Wave Breaking near the Asian Jet Exit Region

Abrupt enhancement of convective activity over the subtropical western North Pacific around 20°N, 150°E is known as the convection jump (CJ) caused by the ocean–atmosphere coupling, which is one of the important factors inducing the end of the Baiu season in Japan. Using atmospheric reanalysis and observation data for 1974–2021, this diagnosis is made for the influences of Rossby wave propagation and breaking, high-potential vorticity (PV) intrusion, and cutoff lows over the western North Pacific on CJ occurrence.