Former Tropical Storm Tapah strengthened into a typhoon southwest of Japan on Saturday. At 11:00 a.m. EDT on Saturday the center of Typhoon Tapah was located at latitude 29.2°N and longitude 125.9°E which put it about 380 miles (610 km) southwest of Nagasaki, Japan. Tapah was moving toward the north at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 972 mb.
The circulation around Typhoon Tapah was very large. Winds to tropical storm force extended out 250 miles (400 km) from the center of circulation. There was a large eye with a diameter of 60 miles (95 km) at the center of Typhoon Tapah. The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the large eye of Tapah. It appeared on satellite imagery as if some drier air might be wrapping around the southeastern side of the circulation.
Typhoon Tapah will move through an environment that could allow it to maintain its current intensity for another 12 to 24 hours. Tapah will move over water where the Sea Surface Temperature is near 28°C. An upper level trough over eastern Asia will produce southwesterly winds which will cause some vertical wind shear, but the shear may not be strong enough to weaken Tapah today. Typhoon Tapah will move under stronger upper level westerly winds in the middle latitudes on Sunday and the increase in wind shear will weaken the typhoon. Stronger wind shear and cooler Sea Surface Temperatures will cause Typhoon Tapah to begin a transition into an extratropical cyclone on Sunday.
Typhoon Tapah will move around the western end of a subtropical ridge over the Western North Pacific Ocean during the next 12 to 18 hours. The ridge will steer Tapah toward the north during that time period. The stronger westerly winds in the middle latitudes will turn Tapah toward the northeast on Sunday. On its anticipated track the center of Typhoon Tapah will be west of Kyushu in about 12 to 18 hours. The center of Tapah could pass between South Korea and Japan on Sunday and then it will move over the Sea of Japan. Because it has such a large circulation Typhoon Tapah could bring gusty winds and locally heavy rain to parts of Kyushu, Honshu and South Korea.