Analysis of recent ocean model-assimilation results suggest that the eastward countercurrent in the Northern Subtropical Pacific may be divided into two branches: one in the Northwestern Pacific (19¿N ~ 27¿N to the west of 170¿E) and the other to the west of the Hawaii Islands (to the west of the 158¿W) along 19¿N ~ 20¿N. Two mechanisms contribute to the formation of the eastward countercurrent to the west of Hawaii: First, the Hawaiian Islands blocks the easterly trade winds and generates a dipole of wind stress vorticity with positive wind curl to the north of the Islands (20¿N ~ 23¿N) and with negative curl to the south (16¿N ~ 19¿N). This dipole of wind stress vorticity acts to create an eastward current jet to the west of the Hawaii Island, through the Sverdrup relation. Second, the islands can directly block the westward North Equator Current (NEC) to generate an eastward current to the west of the islands. We use a numerical model to test these mechanisms for the generation of the eastward countercurrent to the west of the Hawaii Islands. The results show that while the dipole of the wind stress vorticity is helpful in the forming of the eastward countercurrent, and as the NEC impinges upon the Islands the westward traveling vortex streets formed in the ocean plays a key role in intensifying the eastward current to the west of the Hawaiian Islands.