Although tropical storm Bualoi has weakened significantly, its wide-reaching circulation continues to cause dangerous weather conditions across northern and north-central Vietnam, with torrential rains and flooding threatening many areas.

On the morning of September 29, Mai Van Khiem, Director of the National Center for Hydro-Meteorological Forecasting, announced that storm Bualoi had downgraded to level 9 (75-88km/h) with gusts reaching level 11. As of 8 a.m., the storm's center was located inland in southwestern Nghe An.

By around 10 a.m., the storm was forecast to further weaken into a tropical depression and eventually dissipate into a low-pressure zone.

Storm circulation still poses widespread threat

Despite the decreasing intensity, Mr. Khiem emphasized that Bualoi’s circulation still has a broad and dangerous impact. Today, provinces such as Nghe An, Thanh Hoa, and Ha Tinh will continue to experience heavy to extremely heavy rainfall. Rainfall in the northern and north-central regions is expected to range from 150 to 250mm, with some areas potentially receiving over 350mm.

Due to prolonged rainfall, water levels in rivers across north-central and northern provinces are rising rapidly. Many rivers have already reached alarm level 2 or 3, with some surpassing the highest alert thresholds.

In Quang Tri, flood levels on the Kien Giang River exceeded alarm level 3 overnight and, although slightly receding, flooding in riverside communities continues. In Ha Tinh, water levels on the Ngan Sau and Ngan Pho rivers are also rising quickly and are expected to exceed alarm level 3 this morning, posing a serious risk of widespread inundation.

With rainfall exceeding several hundred millimeters over today and tomorrow (September 30), the risk of flash floods and landslides is extremely high in mountainous regions of north-central provinces and the northern midlands and highlands.

Warnings of floods, landslides, storm surges, and strong winds

According to the National Center for Hydro-Meteorological Forecasting, the storm is moving northwest at 20-25 km/h and will continue to weaken into a low-pressure area by 7 p.m. today, positioned over northern Laos.

Along coastal areas from Thanh Hoa to northern Quang Tri (including Hon Ngu Island and Con Co Island), wind speeds are forecast to remain strong, reaching levels 6-7, with areas near the storm center seeing levels 8-9 and gusts up to level 12. Wave heights are expected to reach 3-5 meters, making conditions at sea extremely rough.

In the northern Gulf of Tonkin (including Bach Long Vi, Van Don, Co To, Cat Hai, and Hon Dau), winds of level 6-7 are expected with gusts of level 8-9, and waves between 2-4 meters.

Storm surge warnings have been issued for coastal and island areas from Quang Ninh to Nghe An, with water levels expected to rise by 0.5 to 1 meter. Combined with high tides and large waves, this could result in serious flooding in low-lying areas, coastal roads, and riverbanks, particularly during the morning and midday hours.

On land, areas from Quang Ninh to Ha Tinh may also see strong winds of level 6-7, gusting up to level 9-10, especially near the storm's core.

From today through tomorrow, heavy rainfall is expected across the Red River Delta, Phu Tho, southern Son La, Lao Cai, and from Thanh Hoa to Ha Tinh, with widespread totals between 100 and 200mm. Some locations may exceed 350mm in just a few hours, with warnings for extreme rainfall rates of more than 200mm in three hours.

Other northern provinces are likely to experience moderate to heavy rainfall, with totals ranging from 70 to 120mm and localized areas exceeding 200mm.

Authorities are urging the public to closely monitor weather updates and take proactive measures to prevent loss of life and property due to flash floods, landslides, and urban flooding.

Bao Anh