Tropical Storm Fengshen (Storm No. 12) is forecast to make landfall along the coastal region between Hue and Quang Ngai this afternoon (October 22). Heavy rainfall has already begun lashing areas from Quang Tri to Quang Ngai, posing high risks of flooding and landslides across more than 100 communes and wards.

Experts from the National Center for Hydro-Meteorological Forecasting have issued warnings about the development of Storm No. 12, which is expected to trigger significant rainfall and severe flooding across central Vietnam.

The storm’s path and evolution

On October 17, a low-pressure system east of the Philippines intensified into a tropical depression and by the morning of October 18 had developed into Tropical Storm Fengshen.

By October 19, the storm entered the northern East Sea, becoming the 12th tropical storm of 2025, reaching level 9 intensity with gusts at level 11. It moved northwest at 20-25 km/h.

On October 20, the storm strengthened to level 10 with gusts at level 12. However, it encountered a strong cold air mass from the north, forcing it to shift southwest and slow down.

By the morning of October 22, the storm weakened to level 9. Forecasts suggest that by this afternoon it will approach the coast between Hue and Quang Ngai with further weakening to level 8.

By the night of October 22 into the morning of October 23, the storm is expected to downgrade to a tropical depression and move inland over Hue to Quang Ngai provinces. It will continue to weaken as it reaches southern Laos by midday on October 23.

Three weather systems combine to trigger torrential rain

Due to the impact of cold air, Storm No. 12 will not reach the intensity levels of previous storms such as Bualoi (No. 10) or Matmo (No. 11). The storm’s strength peaked at level 10 but was quickly tempered by the cold front near the Hoang Sa archipelago, causing it to change direction and slow.

Though relatively weak in strength, meteorologists warn that the storm’s moisture-laden circulation will bring significant rainfall. This is due to the combination of moist easterly winds from the East Sea, a strong northeast monsoon over the Gulf of Tonkin, and atmospheric disturbances from the east.

The convergence of wind and moisture from these three systems, amplified by the wind-blocking effect of the Truong Son mountain range, will enhance and prolong rainfall over the central region, even after the storm dissipates.

High winds, storm surge, and tidal threats

Due to the storm’s interaction with the intensifying cold front, the Gulf of Tonkin will experience strong northeast winds at level 7, gusting to level 9.

The coastal waters from Quang Tri to Quang Ngai, including Con Co special zone, Cu Lao Cham island, and Ly Son island, will see wind levels 6-7, with areas near the storm's center reaching level 8 and gusts at level 10. Waves will rise 3-5 meters high, creating extremely rough seas.

Coastal provinces from Quang Tri to Da Nang are forecast to experience storm surge heights of 0.4 to 0.8 meters. There is a high risk of inundation in low-lying areas, coastal roads, and erosion due to large waves, tidal surges, and wind-driven water.

From the afternoon of October 22, coastal areas from Quang Tri to Da Nang will see gradually increasing winds to level 6-7, with gusts at level 8-9. Peak wind conditions are expected from tonight through the morning of October 23.

Specifically, coastal zones will see winds at level 6-7 and gusts at level 8-9, inland regions at level 5 with gusts at level 6-8, and mountainous areas at level 4, occasionally level 5, with gusts at level 6-7.

Meteorologists warn of potential thunderstorms and tornadoes with strong gusts within the storm’s impact zone, both before and during landfall.

Two waves of intense rainfall expected

The first wave, from October 22-24, will result from the interaction of the storm’s circulation, cold air, and easterly winds. Rainfall from Quang Tri to Da Nang is expected to reach 400-600 mm, with localized downpours exceeding 800 mm. Some areas could see over 200 mm of rain in just three hours. Ha Tinh and Quang Ngai may experience 100-250 mm of rainfall, with some places exceeding 400 mm.

This initial rainfall event raises concerns about urban flooding and water stagnation in industrial parks due to high rainfall intensity and storm surges slowing drainage.

The second wave, from October 25-27, will bring additional rain due to continued influence from the cold air and easterly winds. Quang Tri and Hue are forecast to receive 200-300 mm of rain, with some areas exceeding 500 mm. Ha Tinh, Da Nang, and Quang Ngai will see 100-200 mm of rain, with some areas exceeding 300 mm.

Rainfall may persist across central Vietnam even after October 27.

According to meteorological reports, between October 11-20, 2025, total rainfall in Quang Tri to Quang Ngai was 10-30% higher than the same period in previous years. Khe Sanh recorded 106% above average, and Tra My 44% above average.

With rainfall up to this point, combined with forecasts from October 22-30 of an additional 500-700 mm, the total precipitation in the region is expected to exceed annual averages by 20-40%.

Bao Anh