Tropical Storm Yagi formed near the northern Philippines on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Yagi was located at latitude 13.9°N and longitude 124.4°E which put the center about 40 miles (65 km) northeast of Virac, Philippines.  Yagi was moving toward the 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 998 mb.

A low pressure system near the northern Philippines strengthened on Sunday morning and the Japan Meteorological Agency designated the system as Tropical Storm Yagi.  The center of Yagi’s circulation was near Catanduanes Island.  Thunderstorms were forming near the center of Tropical Storm Yagi.  However, the distribution of thunderstorms in Yagi was asymmetrical.  Thunderstorms were forming in bands in the western half of Yagi’s circulation.  Bands in the eastern half of Tropical Storm Yagi consisted primarily of showers and lower clouds.  Storms near the center of Yagi began to generate upper level divergence that pumped mass away from the tropical storm.

Tropical Storm Yagi will move through an environment that will be mostly favorable for intensification during the next 24 hours.  Yagi will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southern part of an upper level ridge over the Western North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Yagi’s circulation.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent Yagi from strengthening.  Tropical Storm Yagi is likely to intensify during the next 24 hours.

Tropical Storm Yagi will move around the western part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Yagi toward the north-northwest during the next 24 hours.  On its anticipated track, the center of Tropical Storm Yagi will move near the east coast of Luzon.  A second high pressure system that is over China will steer Yagi toward the west early next week.

Bands in the western side of Tropical Storm Yagi will drop heavy rain over parts of Luzon.  Heavy rain is likely to cause widespread flooding.