Tropical Storm Sanba Develops Near Palau

Tropical Storm Sanba developed near Palau on Sunday.  At 10:00 a.m. EST on Sunday the center of Tropical Storm Sanba was located at latitude 7.2°N and longitude 133.5°E which put it about 20 miles (35 km) south-southwest of Koror, Palau.  Sanba was moving toward the west at 19 m.p.h. (31 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 1000 mb.

Thunderstorms developed closer to the center of circulation of former Tropical Depression 02W and the Japan Meteorological Agency classified the system as Tropical Storm Sanba.  The distribution of storms was asymmetrical.  The stronger thunderstorms were occurring in bands west of the center of circulation.  The bands in the eastern half of the circulation consisted primarily of showers and lower clouds.  Sanba is moving south of a strong upper level ridge.  The ridge is producing easterly winds which are causing moderate vertical wind shear.  The wind shear is causing the asymmetrical distribution of thunderstorms.

Tropical Storm Sanba will move through an environment marginally favorable for intensification.  Sanba will move over water where the Sea Surface Temperature is near 29°C.  So, there is sufficient energy in the upper ocean to support intensification.  However, the upper level ridge will continue to generate moderate vertical wind shear which will inhibit intensification.  Tropical Storm Sanba could get a little stronger during the next 24 to 36 hours.

The ridge is steering Tropical Storm Sanba toward the west and a general westerly motion is expected to continue.  On its anticipated track Tropical Storm Sanba could approach Mindanao in the southern Philippines in about 36 hours.  Sanba could bring gusty winds and locally heavy rain to parts of the southern Philippines.  Locally heavy rain could cause flash floods.