Weather officials are calling for vigilance after tropical storm Trases formed over waters just north of the main island of Okinawa, southwestern Japan.

The Meteorological Agency said a tropical depression developed into the tropical storm over waters 40 kilometers north of the city of Naha at noon on Sunday.

Agency officials are warning of heavy rain, strong winds and high waves, as Trases is already coming near the main island of Okinawa.

They say the storm had a central atmospheric pressure of 998 hectopascals, with maximum winds of about 65 kilometers per hour and gusts of up to 90 kilometers per hour.

It is moving north at a speed of 30 kilometers per hour.

Intermittent heavy rains and strong winds are expected, especially on Okinawa's main island region and the Amami region in Kagoshima Prefecture. The seas are expected to remain rough.

Weather officials are calling on people to be on the alert for landslides, flooding in low-lying areas, sudden swelling of rivers, strong winds and high waves.

The storm is expected to continue to move north over waters west of Kyushu, and become a tropical depression as early as around noon on Monday.

Agency officials are calling on people to stay informed of the latest weather updates.