Downstream Development of the Summertime TC/Sub-monthly Wave Pattern in the Extratropical North Pacific

The impact of tropical perturbation on the extratropical wave activity in the North Pacific in the sub-monthly time scale is demonstrated here. Previous studies identified a tropical cyclone (TC)/sub-monthly wave pattern, which propagated north-northwestward in the Philippine Sea and re-curved in the oceanic region between Japan and Taiwan. This study found that after the arrival of the TC/sub-monthly wave pattern at the recurving region, the eastward-propagating wave activity in the extratropical North Pacific was significantly enhanced. It is suggested that the TC/sub-monthly wave pattern, which is originated in the tropical western North Pacific, initiates the eastward energy propagation of Rossby-wave-like perturbation in the extratropical North Pacific and may have impact on the long-range weather predictability in the eastern North Pacific and western North America.