Tropical Storm Pulasan Forms Southeast of Ryukyu Islands

Tropical Storm Pulasan formed over the Western North Pacific Ocean southeast of the Ryukyu Islands on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Pulasan was located at latitude 19.3°N and longitude 137.8°E which put the center about 450 miles (725 km) south-southwest of Iwo To.  Pulasan was moving toward the west-northwest at 22 m.p.h. (35 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 997 mb.

The circulation around Tropical Storm Pulasan was very large, but there were not many thunderstorms present.  Bands revolving around the center of Pulasan’s circulation consisted primarily of showers and lower clouds.  Thunderstorms were occurring in a band in the far eastern periphery of Tropical Storm Pulasan.  Thunderstorms were also occurring in a band in the far southern periphery of Pulasan’s circulation.

The circulation around Tropical Storm Pulasan was very large, but the distribution of wind speeds was asymmetrical.  Winds to tropical storm force extended out 265 miles (425 km) in the eastern side of Pulasan’s circulation.  The winds in the western side of Tropical Storm Pulasan were blowing at less than tropical storm force.

Tropical Storm Pulasan will move through an environment marginally favorable for intensification during the next 24 hours.  Pulasan will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the eastern side of a large upper level low centered east of Taiwan.  The upper level low will produce southwesterly winds that will blow toward the top of Pulasan’s circulation.  Those winds will cause strong vertical wind shear.  The strong wind shear will inhibit intensification.  Tropical Storm Pulasan could intensify a little during the next 24 hours if the wind shear does not get any stronger.

Tropical Storm Pulasan will move around the northern side of a large counterclockwise circulation sometimes called a monsoon gyre.  The large counterclockwise circulation will steer Pulasan quickly toward the west-northwest during the next 36 hours.  On its anticipated track Tropical Storm Pulasan will be near the Ryukyu Islands in 36 hours.

Tropical Storm Pulasan will bring gusty winds and locally heavy rain to the Ryukyu Islands.  Heavy rain could cause flash floods in some locations.

Elsewhere, former Typhoon Bebinca weakened to a tropical depression over eastern China.  At 11:00 p.m. EDT on Monday the center of Tropical Depression Bebinca was located at latitude 32.0°N and longitude 117.0°E which put the center about 100 miles (160 km) west of Nanjing, China.  Bebinca was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1004 mb.