Typhoon Chan-hom Turns Toward Japan

Typhoon Chan-hom turned toward Japan on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Chan-hom was located at latitude 27.5°N and longitude 132.9°W which put it about 515 miles (825 km) south-southwest of Osaka, Japan.  Chan-hom was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 973 mb.

Typhoon Chan-hom strengthened slowly on Wednesday.  An eye with a diameter of 35 miles (55 km) formed at the center of Chan-hom.  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 core of Typhoon Chan-hom.  Storms near the core generated upper level divergence which pumped mass away to the northeast of the typhoon.

The circulation around Typhoon Chan-hom was large.  Winds to typhoon force extended out 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out 200 miles (320 km) from the center of Chan-hom.

Typhoon Chan-hom will move through an environment somewhat favorable for intensification during the next 24 hours.  Chan-hom will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western end of an upper level ridge.  The ridge will produce southerly winds which will blow toward the top of Typhoon Chan-hom.  Those winds will cause moderate vertical wind shear, which will inhibit intensification.  The wind shear will limit intensification, but Chan-hom could get stronger during the next 24 hours.  An upper level trough over eastern Asia will cause stronger southwesterly winds to blow toward Typhoon Chan-hom in a day or so.  Those winds will cause stronger vertical wind shear and they will cause Chan-hom to start to weaken.

Typhoon Chan-hom will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next 48 hours.  The high will steer Chan-hom toward the north during that time period.  The upper trough over eastern Asia will turn Typhoon Chan-hom toward the northeast during the weekend.  On its anticipated track Typhoon Chan-hom will be southeast of Kyushu and south of Shikoku in about 48 hours.