Tropical Storm Fengshen (#30W) – Tropical Cyclone Advisory #9: 0000 UTC 20 October 2025

…Outermost rainbands of Fengshen producing heavy rain and strong winds in Hong Kong, Macau, and Taiwan…

Current storm information:

• Position: 18.4°N 114.1°E

• Movement: W at 15 knots (25 km/h)

• Intensity: 45 knots (85 km/h)

• Central pressure: 998 hPa

Trend:

• Some additional strengthening is forecast during the next 24 hours.

Discussion:

Fengshen continues to slowly recover from its passage over Luzon, although it remains a rather poorly organized system. Although the convection has increased in coverage near the circulation center and is organized into somewhat ragged looking bands, available scatterometer data and a recent RCM-3 SAR pass indicate that Fengshen’s circulation is sharply elongated from southwest to northeast. The wind field is also somewhat lopsided to the northeast of the center, although some of the strong winds are a product of a cold surge/gap wind event in the Taiwan Strait that is itself producing winds of 40 to 45 kts. Available estimates are more or less all over the map, with the automated CIMSS ADT and D-PRINT around 40 kts, while manual Dvorak estimates range from T3.0 to T3.5 (45 to 55 kts). Given how elongated the circulation has become, the intensity is held at 45 kts, near the lower end of this range.

Fengshen is currently in the process of turning toward the west-southwest as it begins to encounter the strong northeasterly surface flow coming off the Taiwan Strait. For the moment, environmental conditions should allow for some additional strengthening during the next 24 hours or so as SSTs are quite warm and shear is low, and a trough to the north is generating strong poleward outflow. Fengshen has an outside chance of becoming a typhoon on Tuesday. However, beginning late Tuesday night or early Wednesday, the cool, stable air associated with the cold surge will likely overwhelm Fengshen. Despite the warm SSTs and low shear, the cold surge should very quickly erode Fengshen’s convection to the point that Fengshen will likely become a post-tropical cyclone before reaching the Vietnam coast on Thursday. It is possible that Fengshen could even dissipate outright before reaching the coast, and in fact most of the GFS, ECMWF, Google DeepMind, and HAFS-A guidance lose the vortex just before landfall.

Forecast positions and maximum winds

• 000 hrs: 18.4°N 114.1°E – 45 kts 

• 012 hrs: 18.1°N 112.6°E – 55 kts

• 024 hrs: 17.3°N 111.7°E – 60 kts

• 048 hrs: 15.6°N 109.5°E – 40 kts Post-tropical

• 072 hrs: 14.2°N 107.5°E – 20 kts Post-tropical/remnant low inland

• 096 hrs: Dissipated