Tropical Storm Prapiroon formed over the South China Sea on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Prapiroon was located at latitude 16.3°N and longitude 111.2°E which put the center about 260 miles (460 km) south-southeast of Haikou, China.  Prapiroon was moving toward the west at 5 m.p.h. (8 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 998 mb.

Former Tropical Depression 04W strengthened on Saturday night and the Japan Meteorological Agency designated the system as Tropical Storm Prapiroon.  The circulation around Tropical Storm Prapiroon was exhibiting a little more organization.  There were not a lot of thunderstorms near the center of Prapiroon’s circulation.  Thunderstorms were occurring in bands revolving around the center of Tropical Storm Prapiroon.

Although the circulation around Tropical Storm Prapiroon was large, the area of stronger winds was relatively small.  Winds to tropical storm force extended out 60 miles (95 km) from the center of Prapiroon’s circulation.

Tropical Storm Prapiroon will move through an environment somewhat favorable for intensification during the next 24 hours.  Prapiroon will move over water where the Sea Surface Temperatures are near 30°C.   It will move under the southeastern part of an upper level ridge over China.  The upper level ridge will produce northeasterly winds that will blow toward the top of Prapiroon’s circulation.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification but the shear may not be strong enough to prevent some strengthening.  Tropical Storm Prapiroon could intensify a little during the next 24 hours.

Tropical Storm Prapiroon will move around the southern part of a high pressure system over eastern China.  The high pressure system will steer Prapiroon toward the northeast during the next 24 hours.  On its anticipated track Tropical Storm Prapiroon will move toward Hainan.

Tropical Storm Prapiroon will bring gusty winds and heavy rain to Hainan during the next 24 hours.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Gaemi strengthened gradually east of the Philippines.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Gaemi was located at latitude 17.0°N and longitude 125.5°E which put the center about 485 miles (780 km) south of Ishigakijima, Japan.  Gaemi was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 996 mb.