Tropical Storm Halong developed east of the Marianas on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Halong was located at latitude 13.3°N and longitude 156.7°E which put it about 820 miles (1325 km) east of Guam.  Halong was moving toward the northwest at 9 m.p.h. (15 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.

A distinct low level center of circulation formed in an area of thunderstorms east of the Marianas on Saturday.  When more thunderstorms formed near the center of circulation, the Japan Meteorological Agency designated the system as Tropical Storm Halong.  The circulation around Halong appeared to be organizing quickly.  New thunderstorms were forming close to the center of circulation.  Bands of showers and thunderstorms were also organizing quickly and the bands were starting to revolve around the center of Tropical Storm Halong.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical storm in all directions.  Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation.

Tropical Storm Halong will move through an environment favorable for intensification during the next two to three days.  Halong will move over water where the Sea Surface Temperature is near 29°C.  It will move under the western end of an upper level ridge over the Western North Pacific Ocean.  The winds will be blowing from the south at all levels and so there will be little vertical wind shear.  Tropical Storm Halong will continue to intensify and it could strengthen rapidly.  Halong is likely to strengthen into a typhoon within 36 hours.

The ridge over the Western North Pacific will steer Tropical Storm Halong toward the northwest during the next several days.  On its anticipated track Halong will be northeast of the Marianas by the end of the weekend.