Saudel Weakens to a Tropical Storm

Former Typhoon Saudel weakened back to a tropical storm over the South China Sea on Friday. At 11:00 p.m. EDT on Friday the center of Tropical Storm Saudel was located at latitude 17.7°N and longitude 113.1°E which put it about 170 miles (280 km) east-southeast of Hainan. Saudel was moving toward the west at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 984 mb.

Tropical Storm Saudel weakened over the South China Sea on Friday. An upper level ridge over eastern Asia produced easterly winds which blew toward the top of Saudel. Those winds cause moderate vertical wind shear and they were the primary cause of the weakening of the former typhoon. Breaks developed in the ring of strong thunderstorms surrounding the eye. The distribution of thunderstorms became more asymmetrical. The strongest thunderstorms were occurring in bands in the western half of Tropical Storm Saudel. Bands in the eastern half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 200 miles (320 km) from the center.

Tropical Storm Saudel will move through an environment unfavorable for intensification during the next several days.  Saudel will move over water where the Sea Surface Temperature is near 29°C.  However, the upper level ridge over eastern Asia will continue to cause moderate vertical wind shear. The wind shear, will cause Tropical Storm Saudel to continue to weaken during the weekend.

Tropical Storm Saudel will move south of a ridge of high pressure over eastern Asia.  The ridge will steer Saudel toward the west during the next several days.  On its anticipated track Tropical Storm Saudel will pass south of Hainan Island in about 24 hours. Saudel could approach the coast of Vietnam in about 36 hours. Saudel could still be a tropical storm when it approaches makes landfall on the central coast of Vietnam between Hue and Vinh. Even if Saudel weakens to a tropical depression, it will still drop locally heavy rain over parts of Vietnam and southern Laos. The heavy rain will cause floods in some locations where the ground is already saturated.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Twentyone-W developed east of Luzon. At 11:00 p.m. EDT on Friday the center of Tropical Depression Twentyone-W was located at latitude 12.7°N and longitude 130.7°E which put it about 315 miles (510 km) east of Luzon. The depression was moving toward the west-northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 35 m.p.h. (505 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1006 mb. The depression is forecast to move toward the Philippines and to strengthen into a tropical storm.