WPAC Tropical Weather Outlook - 8/20/25

Tropical Storm 18W should dissipate over Japan in a day or two. Invest 90W still has not developed, and does not appear likely to do so until it's past the Philippines

Author

Will Weaver
August 20, 2025

Active tropical cyclones:

  • Tropical Storm 18W, located off the coast of Kyushu. Refer to tropical cyclone advisories.

Disturbances/invest areas:

  • Invest 90W (east of Luzon): A large area of disturbed weather located in the west central Philippine Sea well to the east of Luzon is associated with a vigorous tropical wave. Satellite and scatterometer data indicates that this wave still has not closed off into a low pressure area, although its forward speed has slowed during the last 24 hours. Environmental conditions are conducive for this system to form into a closed low by the end of the week, although it appears unlikely to become a tropical cyclone before it moves over Luzon this weekend. Once the system enters the South China Sea, environmental conditions should be conducive for development, and a tropical depression will likely form by Sunday or Monday as it meanders in the central South China Sea, then begins moving northwestward.

    Formation chance through 48 hours: LOW - 30% 🟡

    Formation chance through 7 days: HIGH - 70% 🔴