Severe Tropical Storm Fengshen (30W) – Tropical Cyclone Advisory #12: 0000 UTC 21 October 2025

…Fengshen stronger than previously suspected but still forecast to weaken rapidly prior to landfall…

Current storm information:

• Position: 17.2°N 110.5°E

• Movement: WSW at 5 knots (10 km/h)

• Intensity: 55 knots (100 km/h)

• Central pressure: 991 hPa

Trend:

• Rapid weakening is forecast during the next 24 hours.

Discussion:

Scatterometer data and SAR observations since the previous advisory indicate that Fengshen was stronger than previously indicated at that time. Both ASCAT and Sentinel-1 indicated that Fengshen was producing winds of 50 to 55 kts primarily to the north of the center. Since then, Fengshen remains fairly well organized from a convective standpoint, consisting of a well-defined central dense overcast situated just to the north and northwest of a partially exposed and slightly elongated circulation center. Microwave satellite imagery even indicates the presence of a partial eye feature. During the past couple of hours, though, convective cloud tops have begun warming fairly rapidly and the banding within the CDO has taken on a ragged appearance. Although Fengshen continues to sport strong radial outflow, the poleward outflow channel is displaying an almost extreme amount of feathering, indicative of very strong shear. Dvorak estimates range from T3.5 to T4.0, with D-PRINT estimating 46 kts. Taking a blend of these estimates supports an intensity of 55 kts, which could be generous.

Except for the higher initial intensity, there are no changes to the forecast. Given how quickly the convection has begun to weaken, it appears that the cold surge has begun to infiltrate Fengshen’s circulation, and this should result in continued rapid weakening as Fengshen approaches the Vietnam coast. Most of the model guidance continues to dissipate Fengshen’s circulation just as it crosses the coast on Thursday morning.

Forecast positions and maximum winds

• 000 hrs: 17.2°N 110.5°E – 55 kts 

• 012 hrs: 16.6°N 109.7°E – 40 kts

• 024 hrs: 16.2°N 108.4°E – 25 kts

• 048 hrs: Dissipated