Storm Wipha to bring downpours, possible flooding to northern, central Vietnam

According to the National Center for Hydro-Meteorological Forecasting, as of Monday morning Wipha had entered the northern part of the Gulf of Tonkin.

At 10 a.m., its center lay 190 km east of Quang Ninh, 310 km east of Hai Phong, 340 km east-northeast of Hung Yen, and 360 km east-northeast of Ninh Binh.

Winds near the eye average 75–88 kph and gust up to 103–117 kph.

The system might intensify to 103–117 kph within Monday, with gusts of 150–166 kph, as it moves toward the waters off Hai Phong and Thanh Hoa, and is expected to maintain its strength.

It is then likely to move inland over the north-central region between Thanh Hoa and Nghe An provinces and weaken into a low-pressure area over Laos.

Nguyen Thanh Binh of the weather office’s remote sensing forecast division, said Wipha made landfall over southern China last night as a typhoon and slowed down as it entered the Gulf of Tonkin this morning.

But in recent hours it has picked up speed again, moving west-northwest at about 15 kph, she said.

"Currently storm clouds cover the entire northeastern region, but the rain-producing convective clouds are still concentrated in a narrow area, and so Hanoi and the northern delta have yet to experience much rain."

As the storm nears the coast, the cloud system is expected to stabilize, and the convective rain clouds will move inland, leading to a rapid increase in rainfall.

The heaviest rainfall is expected from tonight through tomorrow morning, as the eye approaches land.

Forecasts for Monday-Wednesday expect rainfall of 200–350 mm, exceeding 600 mm in some areas,in the northeast, home to Quang Ninh, and the northern delta, home to Hanoi, as well as the central provinces of Thanh Hoa and Nghe An.

Other areas in the north and the central Ha Tinh Province might receive 100–200 mm, and over 300 mm in some places.

There is a high risk of extreme rainfall in some places, with over 150 mm falling within just three hours.

"Heavy rain can cause flooding in low-lying areas and landslides and flash floods in mountainous regions," Binh said.

"Landslides may occur especially after the storm weakens, as the soil becomes saturated."

She said that even after the storm moves into Laos, northern and north-central Vietnam would continue to get rain due to the influence of the tropical convergence zone.

The heavy rains will cause rivers in the north, Thanh Hoa and Nghe An to experience flood waves of three to six meters from tonight through Friday.