Tropical Storm Bebinca formed near Guam on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Bebinca located at latitude 13.6°N and longitude 144.0°E which put the center about 20 miles (30 km) southwest of Guam.  Bebinca was moving toward the west-northwest at 13 m.p.h. (20 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 999 mb.

Tropical Storm Warnings were in effect for the coastal waters of Guam, Rota, Tinian and Saipan.

A low pressure system near Guam strengthened on Tuesday and the Japan Meteorological Agency designated the system as Tropical Storm Bebinca.  Bebinca brought wind and rain to the Marianas.  A weather station at Guam International Airport (PGUM) reported a sustained wind speed of 28 m.p.h. (45 km/h) and a wind gust of 45 m.p.h. (73 km/h).

The circulation around Tropical Storm Bebinca was exhibiting more organization on Tuesday afternoon.  More thunderstorms developed near the center of Bebinca’s circulation.  Thunderstorms also formed in bands in the eastern side of Tropical Storm Bebinca.  Bands in the western side of Bebinca’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Bebinca generated upper level divergence that pumped mass away from the tropical storm.  The removal of mass caused the pressure to decrease.

The distribution of winds speeds in Tropical Storm Bebinca was asymmetrical.  Winds to tropical storm force extended out 100 miles (160 km) in the northeastern quadrant of Bebinca’s circulation.  Winds to tropical storm force only extended out 25 miles (40 km) in the other parts of Tropical Storm Bebinca.

Tropical Storm Bebinca will move through an environment favorable for intensification during the next 24 hours.  Bebinca will move over water where the Sea Surface Temperatures are near 30°C.   It will move under the western part of an upper level ridge over the Western North Pacific Ocean.  The upper level ridge will produce southerly winds that will blow toward the top of Bebinca’s circulation.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Storm Bebinca will intensify during the next 24 hours.  Bebinca is likely to strengthen to a typhoon later this week.

Tropical Storm Bebinca will move around the southwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Bebinca toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Bebinca will move west of the Marianas.  Bebinca could approach the Ryukyu Islands by the end of the week.