Tropical Depression (92W) - Tropical Cyclone Advisory #1, 0000 UTC 6/10/25

…Depression likely to intensify into a tropical storm as it approaches Hainan Island…

Current storm information:

• Position: 14.9°N 115.1°E

• Movement: WNW at 5 knots (10 km/h)

• Intensity: 30 knots (55 km/h)

• Central pressure: 999 hPa

Trend:

• Some strengthening is forecast during the next 24 hours, and the depression will likely become a tropical storm tonight or on Wednesday.

Watches and warnings:

• No land-based watches or warnings are currently in effect.

Hazards affecting land:

• The depression is likely to produce very heavy rainfall over portions of Hainan Island beginning on Thursday. This rainfall is expected to spread over southern China, including Macau and Hong Kong, by the end of the week and over the weekend. Since 92W will be relatively slow-moving, this rainfall is likely to cause widespread severe flooding. For further information, including possible warnings, refer to products from your local weather office.

Discussion:

Convection associated with the tropical depression in the central South China Sea has quickly expanded in coverage and consolidated, but the system continues to sport monsoon depression characteristics. Convective cloud tops are quite cold, reaching -85°C in spots, but the circulation remains quite broad and poorly defined. HY-2B and Oceansat scatterometer data from several hours ago indicated that the depression was producing a large swath of 25 to 30 knot winds primarily west of the estimated center. Given the increase in organization, JMA has upgraded the depression to warning status with 30 kt winds.

TD 92W will likely be slow to intensify, owing to its broad circulation and a rather marginal upper-air environment with about 15 to 20 kts of easterly shear. However, the shear is forecast to relax somewhat as the broad, upper-level monsoonal circulation 92W is currently embedded in breaks down later today and subtropical ridging builds westward. This should also begin nudging 92W west-northwestward. The more favorable environment should allow 92W to consolidate, and it is forecast to become a tropical storm late tonight or tomorrow. As the circulation becomes better defined, 92W will likely intensify at a faster rate, though land interaction with Hainan Island will likely preclude rapid intensification. Much of the model guidance suggests that 92W will turn northward into a weakness in the ridge and pass just east of (or possibly over) Hainan Island through the end of the week. 

By this weekend, 92W should turn northeastward and accelerate as it makes landfall in southern China west of Macau. Passage over land, increasing shear, and interaction with the meiyu/tsuyu front will cause rapid weakening, and 92W will likely be undergoing extratropical transition over eastern China by the end of the forecast period.

Forecast positions and maximum winds

00 hrs: 14.9°N 115.1°E - 30 kts Tropical Depression

12 hrs: 15.3°N 114.2°E - 30 kts Tropical Depression

24 hrs: 15.9°N 113.4°E - 35 kts Tropical Storm

48 hrs: 16.9°N 111.6°E - 45 kts Tropical Storm

72 hrs: 18.8°N 110.6°E - 55 kts Severe Tropical Storm

96 hrs: 21.2°N 110.8°E - 55 kts Severe Tropical Storm

120 hrs: 25.0°N 114.0°E - 35 kts Tropical Storm (inland)