Tropical Storm Dolphin passed southeast of Japan on Wednesday.  At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Dolphin was located at latitude 32.9°N and longitude 141.4°E which put it about 200 miles (320 km) south-southeast of Tokyo, Japan.  Dolphin was moving toward the northeast at 19 m.p.h. (31 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 986 mb.

An upper level trough over eastern Asia steered Tropical Storm Dolphin quickly toward the northeast on Wednesday.  The trough carried Dolphin southeast of Tokyo.  Winds to tropical storm force extended out 175 miles from the center of Dolphin.  The northern periphery of tropical storm Dolphin was bringing gustier winds to parts of the coast of Honshu.  Most of the rain falling in Tropical Storm Dolphin fell southeast of Honshu.

The upper level trough will carry Tropical Storm Dolphin east of Japan.  Although Dolphin is currently over water where the Sea Surface Temperature is near 28°C, the tropical storm will soon move over cooler water.  The upper level trough and the cooler water will cause Tropical Storm Dolphin to make a transition to an extratropical cyclone during the next several days.

Tropical Storm Dolphin formed south of Japan on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Dolphin was located at latitude 26.0°N and longitude 135.0°E which put it about 365 miles (590 km) southwest of Tokyo, Japan.  Dolphin was moving toward the north-northeast at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 996 mb.

A distinct low level center of circulation developed near the southern side of an area of thunderstorms south of Japan on Monday and the Japan Meteorological Agency designated the system as Tropical Storm Dolphin.  The circulation around Tropical Storm Dolphin was still organizing.  The strongest thunderstorms were occurring in bands in the northern half of the circulation.  Bands in the southern half of Dolphin consisted primarily of showers and lower clouds.  Storms near the center of circulation generated upper level divergence which pumped mass away to the northeast of the tropical storm.  Winds to tropical storm force extended out 125 miles (200 km) from the center.

Tropical Storm Dolphin will move through an environment somewhat favorable for intensification during the next 36 hours.  Dolphin will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough approaching Japan from the west will produce southwesterly winds which will blow toward the top of Tropical Storm Dolphin.  Those winds will cause moderate vertical wind shear and they will inhibit intensification of Dolphin.  The shear will limit intensification, but Tropical Storm Dolphin is likely to get stronger during the next 36 hours.

Tropical Storm Dolphin will move around the northwestern part of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Dolphin toward the north-northeast during the next 24 to 36 hours.  Tropical Storm Dolphin will reach the westerly winds in the middle latitudes after that period and those winds will steer Dolphin more toward the northeast during the middle of the week.  On its anticipated track Tropical Storm Dolphin could approach the coast of Honshu near Tokyo in about 72 hours.