At around 7 a.m. on Wednesday Mun lay centered 220 kilometers from Bach Long Vi Island in the Tonkin Gulf and around 340 kilometers south-southeast of Quang Ninh, home to the world-famous Ha Long Bay, with winds of 75 kph.

The storm will move at a speed of 15 kilometers per hour west-northwest for the next 24 hours, according to the National Center for Hydro-Meteorological Forecasting.

The center predicted its center would be on the coast between Quang Ninh and Ninh Binh provinces by 7 a.m. Thursday, with wind speeds remaining unchanged.

Weather reports from Hong Kong, mainland China and Japan said the storm would make landfall over the northern coast between Quang Ninh and Hai Phong port city at 4 a.m. on Thursday.

According to U.S.-based weather station AccuWeather, Mun will move on a northwesterly course into northern Vietnam near the border with China after reaching the Gulf of Tonkin, bringing rainfall of 150-300 mm in Vietnam and southern parts of Guangxi Province in China. Rainfall of 180 mm in a day is considered heavy.

Due to the effects of the tropical storm, rough waters are expected in the Gulf of Tonkin, including around tourist islands Bach Long Vi, Co To and Cat Hai, from Wednesday afternoon.

Meteorologists also predicted central provinces Ha Tinh, Quang Binh, Thanh Hoa, and Nghe An, which have been recently affected by forest fires, as well as the nearby city Da Nang, would be battered by heavy rains from Wednesday.

Provinces further north such as Hoa Binh and Son La, the northern delta and Hanoi should expect torrential rains on Wednesday and Thursday.

Preparations

In Quang Ninh Province, authorities have banned fishing boats and ships from sailing out to sea from 11 a.m. Wednesday and instructed more than 5,000 boats to seek shelter from the storm.

More than 160 night cruises in Ha Long Bay, one of the country’s top holiday destinations, have been suspended. More than 300 boats carrying tourists around the bay were only allowed to operate until 11 a.m. Wednesday.

Authorities in the island district of Co To, not far from Ha Long, have been instructed to send 1,600 tourists, including foreigners, to the mainland.

Nguyen Xuan Cuong, deputy head of the Central Steering Committee for Natural Disaster Prevention and Control, said Mun is not a strong storm but it's the first of the season and is threatening an area with vibrant economic activities. "Thus, thorough preparations are necessary."

Mun claimed its first victim when it was just a tropical depression on Monday afternoon. Waves of over two meters sunk a vessel carrying 50,000 liters of diesel off Binh Thuan Province in the south central coast.

Local officials are scrambling to remove the oil from the ship and preparing to deal with possible spills.

The stormy season is coming a month late this year. The country was struck by nine tropical storms last year. Storm Pabuk, the latest one, hit southern Vietnam in January, causing no casualties.

Natural disasters, mostly floods, storms and landslides, killed 181 people and left 37 others missing last year and caused losses of around VND20 trillion ($858 million).