Tropical Storm Choi-wan neared the central Philippines on Monday night. At 11:00 p.m. EDT on Monday the center of Tropical Storm Choi-wan was located at latitude 10.4°N and longitude 126.9°E which put it about 100 miles (160 km) east-southeast of Guiuan, Philippines. Choi-wan was moving toward the west-northwest at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 997 mb.
Tropical Storm Choi-wan was approaching Samar in the central Philippines on Monday night. An upper level ridge centered near Hong Kong was producing northeasterly winds that were blowing toward the top of Choi-wan. Those winds were causing moderate vertical wind shear and they were affecting the structure of the tropical storm. The stronger thunderstorms were occurring bands southwest of the center of Tropical Storm Choi-wan. The bands in the other parts of Choi-wan consisted mainly of showers and lower thunderstorms. Winds to tropical storm force extended out 65 miles (105 km) from the center of circulation.
Tropical Storm Choi-wan will move through an environment only marginally favorable for intensification during the next 12 hours. Choi-wan will move over water where the Sea Surface Temperatures are near 30°C. However, the upper level ridge will continue to cause moderate vertical wind shear. The wind shear will limit the potential for intensification. The center of Tropical Storm Choi-wan will move over land later on Tuesday.
Tropical Storm Choi-wan will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean. The high pressure system will steer Choi-wan during the next 36 hours. On its anticipated track the center of Tropical Storm Choi-wan will reach Samar in 12 hours. Choi-wan will bring gusty winds and locally heavy rain to Samar. Heavy rain could cause flash floods in some locations. The center of Tropical Storm Choi-wan could reach the southeastern part of Luzon in 24 hours.