Two new tropical storms with the names of Mujigae and Choi-Wan have formed over the western North Pacific Ocean. At 11:00 a.m. EDT on Friday the center of Tropical Storm Mujigae was located at latitude 17.4°N and longitude 117.3°E which put it about 275 miles (445 km) northwest of Manila, Philippines. Mujigae was moving toward the west-northwest at 17 m.p.h. The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 990 mb.
At 11:00 a.m. EDT on Friday the center of Tropical Storm Choi-Wan was located at latitude 19.2°N and longitude 166.4°E which put it about 15 miles (20 km) south-southeast of Wake Island. Choi-Wan was moving toward the west-northwest at 3 m.p.h. (5 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 996 mb.
Tropical Storm Mujigae organized quickly after the system move west of the Philippines. A primary curved rainband wrapped around the western and southern sides of the center of circulation. A possible eye is apparent intermittently on infrared satellite imagery. Upper level divergence is beginning to occur both north and south of the center. Mujigae is moving over water where the Sea Surface Temperature is near 28°C and there is not enough vertical wind shear to prevent intensification. A period of rapid intensification is possible and Mujigae could become a typhoon in 12 to 24 hours.
A subtropical ridge is steering Mujigae toward the west-northwest and that general motion is expected to continue for the next several days. On its anticipated track, Mujigae could be approaching the southern coast of China in 36 hours. It could bring strong winds and heavy rain when it makes landfall.
Tropical Storm Choi-Wan is still in the organizational stage. It has a large broad circulation without a well developed inner core. Winds to tropical storm force are occurring in clusters of thunderstorms. Choi-Wan is over Sea Surface Temperatures near 29°C, but there is moderate vertical wind shear over the northern part of the tropical storm. The wind shear is expected to decrease in a day or two and Choi-Wan is forecast to become a typhoon.
Choi-Wan is between two subtropical ridges and the steering currents are relatively weak. In a day or two the western ridge is expected to steer Choi-Wan toward the northwest. Choi-Wan will cause squally weather on Wake Island for 24 to 48 hours.