Tropical Storm Kai-tak Moves Over South China Sea

Tropical Storm Kai-tak moved west of the Philippines and over the South China Sea on Tuesday.  At 10:00 p.m. EST on Tuesday the center of Tropical Storm Kai-tak was located at latitude 8.2°N and longitude 112.0°E which put it about 425 miles (685 km) east-southeast of Ho Chi Minh City, Vietnam.  Kai-tak was moving toward the west-southwest at 12 m.p.h. (19 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 1000 mb.

The organization of the circulation of Tropical Storm Kai-tak improved on Tuesday.  More thunderstorms developed near the center of circulation.  The two stronger rainbands were north and west of the center.  However, thunderstorms also developed in a couple of bands southeast of the center of circulation.  These storms were the first to form in the eastern half of the circulation in several days.  The distribution of the rainbands was still asymmetrical, but storms were occurring in more quadrants of Kai-tak.  The storms in the two stronger rainbands were generating some upper level divergence which was pumping mass away to the west of the tropical storm.

Tropical Storm Kai-tak will be moving through an environment somewhat favorable for intensification during the next day or two.  Kai-tak will move over water where the Sea Surface Temperature is near 29°C.  Kai-tak is moving near the southwestern portion of a subtropical ridge.  The ridge is producing easterly winds which are blowing toward the top of the circulation.  The easterly winds are causing moderate vertical wind shear, but they have weakened somewhat during the past 24 hours.  Less wind shear has allowed Tropical Storm Kai-tak to become better organized.  Tropical Storm Kai-tak could strengthen during the next 24 to 36 hours.

The western end of the subtropical ridge is strengthening and the ridge is steering Tropical Storm Kai-tak toward the west-southwest.  A general motion toward the west-southwest is expected to continue for the next two or three days.  On its anticipated track the center of Tropical Storm Kai-tak is expected to pass south of the southern tip of Vietnam.  Kai-tak is forecast to stay north of Borneo.  The center of Tropical Storm Kai-tak could approach the region near the border between Thailand and Malaysia in about 72 hours.