Low-pressure system expected to strengthen in East Vietnam Sea

At 1:00 am on Tuesday, the system’s center was located in the middle of the East Vietnam Sea.

The national weather center estimates a 60-70-percent chance of it strengthening into a tropical depression, though the likelihood of it becoming a storm remains below 10 percent.

The system is mainly expected to bring thunderstorms, rough seas, and winds of 30-50 kph.

The center also warns that one or two strong storms could form east of the Philippines during the last 10 days of September and potentially move into the East Vietnam Sea, affecting Vietnam’s mainland.

Authorities pledged to issue warnings three to five days before any storm approaches.

From October to December, the number of storms and tropical depressions in the East Vietnam Sea and those hitting Vietnam’s mainland is likely to exceed the long-term average.

Typically, the maritime region sees around 4.5 storms annually, with nearly two making landfall.

Central Vietnam is expected to face several rounds of heavy rainfall from October through November, particularly from Ha Tinh to Hue and the eastern provinces from Quang Ngai to Khanh Hoa.

Cold air fronts are also forecast to strengthen in frequency and intensity starting in October, with strong activity predicted in November and December.

Severe cold spells could affect northern Vietnam from mid-December.

Meteorologists caution that the combination of tropical depressions, storms, cold air, and upper easterly winds could trigger extreme rainfall in central provinces, with the risk of historic flooding.

Nguyen Van Huong, head of the weather forecast department at the National Center for Hydro-Meteorological Forecasting, said ENSO is expected to remain in a neutral phase, leaning slightly toward La Niña, from late 2025 to early 2026.

During this period, the East Vietnam Sea could see about 1.4 storms or tropical depressions, with around 0.2 likely to impact the mainland.

“Although storm frequency is projected to be low during this time, tropical depressions, storms, and the northeast monsoon may still cause strong winds and high waves, threatening activities in the East Vietnam Sea,” Huong added.

ENSO, or El Niño-Southern Oscillation, refers to fluctuations between El Niño and La Niña phases.

El Niño years typically bring prolonged heat and drought, delayed rainy seasons, reduced flood, and storm activity.

In contrast, La Niña events are associated with strong and persistent monsoon winds, abundant rainfall, and more frequent storms and tropical depressions.