Tropical Storm Nangka brought wind and rain to Hainan Island on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Nangka was located at latitude 19.1°N and longitude 110.0°E which put it about 70 miles south-southwest of Haikou, China.  Nangka was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 987 mb.

The center of Tropical Storm Nangka moved directly across Hainan Island on Tuesday.  Nangka strengthened before it made landfall on the east coast of Hainan.  Winds to tropical storm force extended out 200 miles (320 km) from the center of Tropical Storm Nangka.  So, Nangka may have produced tropical storm force winds over much of Hainan.  Thunderstorms near the center of circulation and in bands revolving around the center were dropping heavy rain over parts of Hainan.  The heavy rain was likely to cause flash floods in some locations.

Tropical Storm Nangka will weaken while it moves across Hainan.  Nangka will move into an environment favorable for intensification for about 12 hours when it moves west of Hainan Island.  Nangka will move over water where the Sea Surface Temperature is near 29°C.  It will move under the southern part of an upper level ridge over eastern Asia.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent Tropical Storm Nangka from strengthening again.

Tropical Storm Nangka will move south of a high pressure system over eastern Asia.  The high will steer Nangka toward the west during the next 48 hours.  Tropical Storm Nangka will move west of Hainan Island in about 6 hours.  On its anticipated track Nangka will make landfall on the northern coast of Vietnam southeast of Hanoi in about 18 hours.  Tropical Storm Nangka will bring gusty winds and locally heavy rain to northern Vietnam.  Heavy rain will cause flash floods in some locations.