WPAC Tropical Weather Outlook - 6/27/25

Active tropical cyclones:

• There are no tropical cyclones.

Disturbances/invest areas:

• Invest 97W (well north of Palau): Shower activity associated with a monsoonal area of low pressure located in the central Philippine Sea well to the north of Palau remains disorganized. This system is located in a rather hostile environment with strong northwesterly shear associated with a persistent TUTT cell located to the northwest. Despite the hostile conditions, a short-lived tropical depression could form over the weekend as the system meanders in the same general area, but by Monday the system will likely be absorbed by another developing disturbance to its west.

  Formation chance through 48 hours: MEDIUM - 40%

  Formation chance through 7 days: MEDIUM - 40%

• Disturbance A (near Guam): Another area of low pressure located just to the southwest of Guam is producing disorganized showers and thunderstorms. This system is also interacting with another TUTT cell near the northernmost Mariana Islands, which is producing strong shear. This system should begin moving northward during the next couple of days as the TUTT cell moves westward and fills, and it could become a short-lived tropical depression by Monday or Tuesday as it passes over the Marianas. By the middle of next week, upper-level winds will once again become unfavorable for further development. Regardless of development, this system will likely produce areas of heavy rainfall across portions of Guam and CNMI during the next several days.

  Formation chance through 48 hours: MEDIUM - 40%

  Formation chance through 7 days: MEDIUM - 60%

• Disturbance B (east of Samar Island): An area of disturbed weather located well east of Samar is associated with an active monsoon trough. A low pressure area will likely form within this disturbance over the weekend. Due to a number of TUTT cells persisting over the area, conditions will likely be only marginally conducive for development, but a tropical depression could form by Monday or Tuesday as the system turns northeastward well to the east of Luzon and interacts with 97W.

  Formation chance through 48 hours: LOW - 10%

  Formation chance through 7 days: MEDIUM - 40%

• Disturbance C (northwest of Palawan): Yet another area of low pressure is forecast to form along the monsoon trough north of Palawan early next week. Environmental conditions are expected to be conducive for some development, and a tropical depression could form in the central South China Sea by midweek.

  Formation chance through 48 hours: LOW - 10%

  Formation chance through 7 days: MEDIUM - 50%