Tropical Storm “Son-tinh” formed late July 16, 2018, in the South China Sea as the 9th named storm of the 2018 Pacific typhoon season. The main threat as this storm tracks over Hainan and into Vietnam over the next 36 hours will be rain. Another tropical system is expected to form east of the Philippines this week with much more chances to become a typhoon.
Son-tinh passed over the northern Philippines as a tropical depression locally known as Henry. The system combined with the Southwest Monsoon and dropped heavy rain on the country.
At 06:00 UTC on July 17, the center of Tropical Storm “Son-tinh” was located about 524 km (326 miles) southeast of Hong Kong. 10-minute sustained winds were at 65 km/h (40 mph), while 1-minute sustained winds reached 65 km/h (40 mph), with gusts up to 95 km/h (60 mph). The minimum barometric pressure was at 996 hPa, and the system was moving westward at 41 km/h (25 mph).
Animated multispectral satellite imagery shows a compact and symmetric area of convection which is quickly tracking westward.
Son-tinh is currently experiencing moderate to strong vertical wind shear and favorable sea surface temperatures. These marginal environmental conditions will allow for some minor intensification by the end of the day.
However, land interaction with Hainan (expected to begin around 18:00 UTC, July 17) will inhibit additional development.
Son-tinh will emerge over warm seawater in the Gulf of Tonkin around 03:00 UTC, July 18 which will help maintain its intensity of 75 km/h (45 mph).
Landfall in northern Vietnam is expected around 12:00 UTC, July 18.
Tropical Storm “Son-tinh” at 09:00 UTC on July 17, 2018. Credit: JMA/Himawari-8
Image credit: JTWC
Featured image: Tropical Storm “Son-tinh” at 09:00 UTC on July 17, 2018. Credit: JMA/Himawari-8