Typhoon Shanshan Moves Toward Japan

Typhoon Shanshan moved toward Japan on Monday.  At 11:00 a.m. EDT on Monday the center of Typhoon Shanshan was located at latitude 29.2°N and longitude 145.3°E which put it about 585 miles (940 km) southeast of Tokyo, Japan.  Shanshan was moving toward the north-northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 971 mb.

Typhoon Shanshan weakened slightly during the past 24 hours.  It appeared that some drier air may have been pulled into the western half of the circulation.  There was still a circular eye at the center of circulation, but there were breaks in the ring of thunderstorms around the eye.  There were several bands of stronger storms in the eastern and southern parts of the circulation.  Bands north and west of the center of Shanshan consisted primarily of showers and lower clouds.  Storms in the core were generating strong upper level divergence which was pumping mass away from the typhoon.

Typhoon Shanshan will move through an environment that should allow it to remain a typhoon for several more days.  Shanshan will move over water where the Sea Surface Temperature is near 28°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Drier air north and west of Typhoon Shanshan will inhibit the formation of taller thunderstorms in that part of the typhoon and the drier air will limit the potential for intensification.

Typhoon Shanshan will move around the western side of a subtropical ridge over the North Pacific Ocean.  The ridge will steer Shanshan in a general north-northwesterly direction for another two or three days.  When Typhoon Shanshan nears Honshu, an southwesterly winds on the east side of an upper level trough will start to steer the typhoon toward the northeast.  There is still uncertainty about when and where the turn toward then northeast will occur and Typhoon Shanshan could be close to Tokyo in about three days.