WPAC Tropical Weather Outlook - 6/23/25

Tropical Storm Sepat headed toward Japan, invest 96W likely to become a tropical depression near Hong Kong, while another disturbance will pass east of the Marianas late this week

Author

Will Weaver
June 23, 2025

Active tropical cyclones:

  • Tropical Storm Sepat (02W), located south-southeast of Yokosuka, Japan. Refer to tropical cyclone advisories.

Disturbances/invest areas:

  • Invest 96W (west of Mindoro): A broad area of low pressure has formed along the monsoon trough off the western coast of Mindoro. In addition, shower activity associated with this low is showing some signs of organization. Environmental conditions are conducive for development, and a tropical depression is likely to form in the next day or two as the low moves generally northwestward. By Thursday, the system will move inland over southern China east of Hong Kong, ending its development chances.

    Formation chance through 48 hours: MEDIUM - 50%

    Formation chance through 7 days: HIGH - 70%

  • Disturbance A (near Chuuk): A tropical wave located just east of Chuuk is producing a large area of disorganized showers and thunderstorms. A low pressure area is forecast to form along this wave by midweek, and environmental conditions are expected to be conducive for development. A tropical depression is likely to form late this week as the system turns northward and passes east of the Marianas.

    Formation chance through 48 hours: LOW - 10%

    Formation chance through 7 days: HIGH - 70%