Tropical Storm Son-tinh made landfall in northern Vietnam is and is curving to the northeast to track over southern China. NASA's Aqua satellite revealed powerful thunderstorms around the storm's center before it made landfall and as it filled up the Gulf of Tonkin.
On Oct. 28 at 0553 UTC (2:53 a.m. EDT) the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite captured infrared imagery of Tropical Storm Son-tinh that showed a concentration of strong thunderstorms around the storm's center before it made landfall. Son-tinh was located over the Gulf of Tonkin and filled the Gulf. The Gulf of Tonkin is located off the northern Vietnam coast and southern China coast. It is a northern arm of the South China Sea.
The AIRS data showed that Son-tinh's thunderstorms were reaching high into the troposphere where cloud top temperatures are as cold as -63 Fahrenheit (-52 Celsius). Those storms had the potential to drop heavy rainfall at rates of 50 mm/2 inches per hour.
On Oct. 29 at 0300 UTC (11 p.m. EDT, Oct. 28), Son-tinh was over land, 60 nautical miles (69 miles/111 km) northeast of Hanoi, and was still maintaining sustained winds near 60 knots (69 mph/111 kph), just below typhoon strength. It was located near 21.5 North latitude and 107.1 East longitude. It is moving to the east-northeast at 5 knots (7 mph/11 kph).
Wind shear is adversely affecting the storm as it interacts with and moves over land. Son-tinh is expected to remain over land and dissipate by Oct. 31 over southeastern China.