Hanoians wear long-sleeved shirts and raincoats to keep warm during a cold day. — VNA/VNS Photo Minh Quyết

HÀ NỘI — A strengthening cold air mass is bringing heavy to torrential rain and thunderstorms across the northern and central regions, with temperatures forecast to fall to as low as 14-17 degrees Celsius in high mountainous areas and rainfall of more than 200mm possible in parts of the central region.

The cold air mass reached the northeastern region, the northern province of Thanh Hóa and parts of the northwest on Monday morning, pushing temperatures at 7am to 21-24 degrees Celsius.

The cold air mass is forecast to spread to other parts of the northwest areas and localities from Nghệ An to Huế later on Monday.

The northeastern region and Thanh Hóa Province are expected to turn cooler, while high mountainous areas could experience cold weather.

Minimum temperatures during the cold spell are forecast at 18-21 degrees Celsius across the northern region and Thanh Hóa Province, falling to 14-17 degrees Celsius in high mountainous areas.

Hà Nội also turns cooler with the lowest temperature of 22 degrees Celsius on Monday.

Strong northeasterly winds of force 6, occasionally force 7, with gusts up to force 8, are forecast in the Gulf of Tonkin.

Waves are expected to reach 2-3m, resulting in rough seas.

Heavy rain is also forecast to move southwards along the central coast.

From Monday through Tuesday, Hà Tĩnh to Quảng Trị are expected to receive 40-80mm of rain, with isolated areas recording more than 160mm.

On Tuesday, areas from Quảng Trị to Đà Nẵng and eastern Quảng Ngãi are forecast to receive 50-100mm, with isolated areas receiving more than 200mm.

The National Centre for Hydro-Meteorological Forecasting warned that thunderstorms could produce lightning, hail, tornadoes and strong wind gusts, potentially damaging crops, trees, houses, transport infrastructure and other facilities.

Heavy rain could trigger flash floods in small rivers and streams, landslides on steep slopes and flooding in low-lying areas.

Strong winds, gusts and high waves could disrupt maritime activities and pose risks to vessels operating in affected waters. — VNS