Tropical Storm Peipah formed over the Western North Pacific Ocean just to the south of Kyushu on Wednesday evening.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Peipah was located at latitude 30.3°N and longitude 131.4°E which put the center about 110 miles (175 km) south of Miyazaki, Japan.  Peipah was moving toward the north at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 999 mb.

A low pressure system over the Western North Pacific Ocean just to the south of Kyushu strengthened on Wednesday evening and the Japan Meteorological Agency designated the system as Tropical Storm Peipah.

The distribution of thunderstorms in Tropical Storm Peipah was asymmetrical.  Thunderstorms were occurring in bands in the northern and eastern parts of Peipah’s circulation.  Bands in the southern and western parts of Tropical Storm Peipah consisted primarily of showers and lower clouds.  Storms near the center of Peipah generated upper level divergence that pumped mass away to the northeast of the tropical storm.

The distribution of wind speeds in Tropical Storm Peipah was also asymmetrical.  Winds to tropical storm force extended out 85 miles (135 km) in the eastern side of Peipah’s circulation.  The winds in the western side of Tropical Storm Peipah were blowing at less than tropical storm force.

Tropical Storm Peipah will move through an environment somewhat favorable for intensification during the next 24 hours.  Peipah will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the northern part of an upper level ridge that is south of Japan.  The upper level ridge will produce westerly winds that will blow toward the top of Peipah’s circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification but the wind shear may not be enough to prevent intensification.  Tropical Storm Peipah could intensify a little during the next 24 hours.

Tropical Storm Peipah will move around the northern side of a high pressure system that is south of Japan.  The high pressure system will steer Peipah toward the northeast during the next 24 hours.  On its anticipated track, the center of Tropical Storm Peipah will pass just to the east of Kyushu during the next 12 hours.  Peipah could move near the southern coast of Shikoku later on Thursday.  The center of Tropical Storm Peipah could be south of Osaka in 24 hours.

Tropical Storm Peipah will bring gusty winds and locally heavy rain to parts of Kyushu, Shikoku and Honshu.  Heavy rain could cause flash floods in some locations.