Tropical Storm Fengshen (30W) – Tropical Cyclone Advisory #11: 1200 UTC 21 October 2025

…Fengshen beginning to move southwestward…

Current storm information:

• Position: 17.5°N 111.6°E

• Movement: SW at 5 knots (10 km/h)

• Intensity: 45 knots (85 km/h)

• Central pressure: 994 hPa

Trend:

• Rapid weakening is forecast during the next 24 hours.

Discussion:

Fengshen appears to have gotten better organized despite beginning to interact with the northeasterly cold surge over the northern South China Sea. Convection has increased dramatically in coverage and depth, with cloud tops becoming quite cold within the central dense overcast. In addition, the convection has developed into a thick spiral band that is wrapping into the circulation center. The problem, though, is that the circulation center remains somewhat poorly defined, partially exposed, and almost trough-like as indicated by scatterometer data and proxy-visible satellite imagery, and the convection is limited mainly to the north and northeast of the center. Despite the overall increase in organization, this does not appear to have translated into an increase in strength. Dvorak fixes range from T3.5 to T4.0 using the curved band pattern, but scatterometer data only indicates winds of 40 to 45 kts, and the CIMSS ADT and D-PRINT estimates are much lower, with ADT as low as 30 kts. Given this wide range of estimates, the current intensity is held at 45 kts. 

Given that Fengshen is now embedded within the northeasterly cold surge, there are no changes to the forecast. Fengshen should begin to accelerate southwestward later tonight as the surge flow intensifies. Although SSTs are fairly warm (but cooling significantly to the northeast), increasing shear and cool, stable air from the surge flow will cause Fengshen to weaken rapidly during the next day or two, and most of the model guidance now suggests that Fengshen’s circulation will dissipate as it reaches the southern Vietnam coast. This forecast retains a 24-hour forecast point off the coast, but it is likely that Fengshen will be poorly defined and nearly devoid of convection by that time.

Forecast positions and maximum winds

• 000 hrs: 17.5°N 111.6°E – 45 kts 

• 012 hrs: 16.7°N 110.5°E – 35 kts

• 024 hrs: 15.9°N 109.2°E – 30 kts

• 048 hrs: Dissipated