By the afternoon of July 21, the storm's center was approximately 120 km east-northeast of Quang Ninh, 260 km from Hai Phong, 280 km from Hung Yen, and about 310 km from Ninh Binh. Wind speeds had intensified to levels 9-10 (75–102 km/h), with gusts reaching level 12. Compared to three hours earlier, the storm had strengthened by one level and was expected to intensify further.

Nguyen Thanh Binh, a senior forecaster at the Department of Numerical Weather Prediction under the National Center for Hydro-Meteorological Forecasting (NCHMF), provided a detailed analysis of the storm’s developments and impacts.

According to Binh, storm Wipha’s center changed trajectory overnight, first making landfall in southern China before crossing Leizhou Peninsula and heading into the Gulf of Tonkin. Initially slowing down, the storm has recently regained speed, now traveling west-northwest at approximately 15 km/h.

Satellite imagery shows that the storm's cloud system currently covers the entire northeastern region of Vietnam, with parts extending as far as the eastern side of China’s Leizhou Peninsula. However, Binh noted that the thick, rain-bearing convective clouds are currently concentrated in a narrower band, which explains why Hanoi and some northern delta provinces have experienced mostly overcast skies and limited rainfall during the day of July 21.

As the storm stabilizes and possibly strengthens over the Gulf of Tonkin, rainfall is expected to increase. Binh emphasized that, in the coming hours, as the storm approaches Vietnam’s coastal areas, the convective cloud system will move closer and intensify rain levels.

According to the NCHMF, the most significant rainfall is expected to occur from the evening of July 21 through the morning of July 22, when the storm center nears the coast.

The heaviest rainfall is expected in the eastern mountainous regions and the southern Red River Delta, particularly in Thanh Hoa and Nghe An provinces. Extreme rainfall could lead to flash floods and dangerous landslides in mountainous areas, especially in low-lying flood-prone zones.

Binh also warned that landslides can still occur even after the storm has dissipated. Continued moderate rain on saturated soils poses a prolonged risk. "In many cases, even when the rain subsides, landslides can still occur due to weakened, waterlogged terrain," she explained.

Bao Anh