Infrared satellite imagery from NASA's Aqua satellite shows bands of strong thunderstorms wrapping around the center of Tropical Storm Nock-Ten as it makes its way through the South China Sea and two landfalls on Hainan Island and in Vietnam.
Bands of strong thunderstorms that make up tropical storm Nock-ten were visible in an infrared image captured on July 28 by the Atmospheric Infrared Sounder (AIRS) instrument that flies on NASA's Aqua satellite. The colder the cloud tops, the higher the thunderstorms and the stronger they are, and cloud top temperatures over a large area of Nock-ten were colder than -63 Fahrenheit (-52 Celsius) and the cloud tops likely extended into the tropopause. High, strong thunderstorms like those also can generate heavy rainfall, up to 2 inches (50 mm) per hour. Those in Nock-ten's path can expect heavy rainfall, local flooding, gusty winds and rough surf along coastal areas.
AIRS imagery has shown that the convection within Nock-ten has intensified as it moves through the warm waters of the South China Sea. It is expected to strengthen a little more with the warm sea surface temperatures feeding it, and wind shear remaining light.
On July 28, at 1500 UTC (11 a.m. EDT) Tropical Storm Nock-ten was already raining on Hainan Island and headed toward another landfall in Vietnam. Its center was still 464 nautical miles east-southeast of Hanoi, Vietnam near 18.2 North and 113.0 East. Nock-ten's sustained winds are near 55 knots (63 mph/101 kmh) and it is moving in a westerly direction at 12 knots (14 mph/22 kmh).
The Joint Typhoon Warning center forecasters expect that the center of Nock-ten will make landfall over Hainan Island, China before July 29 at 1500 UTC (11 a.m. EDT) and weaken a little as it moves over land. However, once it re-emerges over water in the Gulf of Tonkin, it may strengthen a little before making final landfall in Vietnam.