The end of the rainy (Baiu) season in the Kanto region and northern Japan is induced by a "convection jump," known as the abrupt enhancement of convective activity (precipitation) over the northeast of the Philippines in late July. The intrusion of cyclonic unstable airmass (high-potential-vorticity (PV) airmass) from the upper-tropospheric mid-latitude modulates the convective activity over the subtropical western North Pacific, including the northeast of the Philippines. However, the influence of extratropical upper-tropospheric variations on the convection jump has not been fully discussed.