Tropical Storm Nari strengthened over the Western North Pacific Ocean southeast of Tokyo on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Nari was located at latitude 33.2°N and longitude 143.0°E which put the center about 300 miles (485 km) southeast of Tokyo, Japan.  Nari was moving toward the north at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 984 mb.

Tropical Storm Nari strengthened on Sunday as it moved over the Western North Pacific Ocean southeast of Tokyo.  The structure Nari’s circulation changed when it moved under an upper level low south of Japan.  The inner end of a rainband wrapped around the western and southern sides of the center Tropical Storm Nari.  A region of drier air wrapped around the outside of that rainband.  Thunderstorms were occurring near the center of Naria’s circulation.  Thunderstorms were also occurring in bands in the northeastern part of Tropical Storm Nari.

The distribution of winds speeds in Tropical Storm Nari continued to be asymmetrical.  Winds to tropical storm force extended out 180 miles (290 km) in the eastern side of Nari’s circulation. Winds to tropical storm force extended out 65 miles (105 km) in the western side of Tropical Storm Nari.

Tropical Storm Nari will move through an environment that will be marginally favorable for intensification during the next 12 hours.  Nari will move over water where where the Sea Surface Temperatures are near 28°C.  It will move under the northeastern part of an upper level low south of Japan.  The upper level low will produce southerly winds that will blow toward the top of Nari’s circulation. Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification.  Tropical Storm Nari could intensify a little during the next 12 hours.  Nari will move over colder water later on Monday.  The colder water will cause Tropical Storm Nari to start to weaken.  The colder water will also cause Nari to start a transition to an extratropical storm.

Tropical Storm Nari will move around the western side of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Nari toward the north during the next 24 hours.  On its anticipated track, Tropical Storm Nari will pass east of Honshu.  Nari will be south of Hokkaido in 24 hours.