A strengthening cold air mass moving south, combined with the intertropical convergence zone and upper-level easterly disturbances, is bringing widespread heavy rain to central Vietnam, according to the National Center for Hydro-Meteorological Forecasting.

From 7pm on Oct. 5 to 8am on Oct. 6, rainfall exceeded 200mm in several locations. Ky Anh in Ha Tinh recorded 297mm, Sen Thuy in Quang Tri 427.6mm and Phong Dien in Hue 203.4mm.

The heaviest rain is now shifting southward, with areas from southern Quang Tri to Hue, Da Nang and eastern Quang Ngai expected to bear the brunt of the downpours.

During Oct. 6 and the following night, areas from southern Ha Tinh to Da Nang and eastern Quang Ngai are forecast to receive 50-100mm of rain, with localized totals exceeding 200mm.

Heavy rain will continue on Oct. 7, concentrating from southern Quang Tri to Da Nang and eastern Quang Ngai. Rainfall of 50-100mm is forecast, with some places receiving more than 200mm.

Meteorologists have also warned of intense downpours exceeding 100mm within three hours.

During Oct. 8 and the following night, heavy rain and thunderstorms are expected to persist from southern Ha Tinh to Da Nang, with rainfall of 50-100mm and localized totals above 200mm.

Total rainfall from Oct. 6 through the end of Oct. 8 is forecast at 100-250mm across southern Ha Tinh, Da Nang and eastern Quang Ngai, with some locations receiving more than 400mm.

Particularly heavy rainfall is expected from southern Quang Tri to Hue, where totals could reach 300-400mm and exceed 600mm in some places.

Hue and Da Nang are among the areas facing particularly severe rainfall, prompting meteorological authorities to issue a Level 2 natural disaster risk warning for heavy rain.

Heavy rain could persist until Oct. 11

From the night of Oct. 8, rainfall from Hue to eastern Quang Ngai is expected to gradually ease. However, the rain zone is forecast to shift back northward and expand toward Thanh Hoa.

The widespread heavy rain across central Vietnam could persist until around Oct. 10-11.

Several days of continuous rainfall will increase the risk of flooding in low-lying areas and cities, while mountainous areas face heightened threats of flash floods and landslides.

Residents in affected areas are advised to closely monitor weather forecasts and warnings and take precautions to protect lives and property.

Cold air reaches Quang Ngai as northern Vietnam turns cooler

The cold air mass is continuing to spread southward and is expected to affect other parts of eastern Quang Ngai.

On land, northeasterly winds are forecast at Level 2-3, strengthening to Level 3-4 in coastal areas.

Northern Vietnam and Thanh Hoa will experience cooler conditions at night and in the early morning, with cold weather in some high mountainous areas.

The lowest temperatures during this cold spell are forecast at 18-21 degrees Celsius across much of the north and 14-17 degrees in high mountainous areas.

Hanoi is expected to be sunny during the day and dry at night, with cooler conditions overnight and in the early morning.

At sea, the Gulf of Tonkin is forecast to experience Level 6 northeasterly winds with gusts reaching Level 7-8. Waves could reach 2-3 meters, producing rough seas.

The northern East Sea, including the Hoang Sa special zone, is forecast to experience Level 6-7 northeasterly winds, gusting to Level 8-9, with waves of 2-4 meters and very rough seas.

Ho Chi Minh City and southern Vietnam face flooding risk

Heavy rain is also forecast across parts of southern Vietnam.

On the afternoon and night of Oct. 6, eastern Gia Lai, the Central Highlands and southern Vietnam are expected to see scattered showers and thunderstorms, with rainfall of 10-30mm and localized totals exceeding 70mm.

The Southern Regional Hydro-Meteorological Center said the intertropical convergence zone, combined with cold air extending farther south, is increasing rainfall.

From Oct. 6-8, southern Vietnam is expected to experience frequent rain, including scattered moderate rain and localized heavy to very heavy downpours, mainly around midday, in the afternoon, evening and at night.

Urban areas including Ho Chi Minh City, Can Tho and Lam Dong should be particularly alert to heavy rain and possible flooding on the afternoon and evening of Oct. 6.

Residents are advised to watch for flooding in low-lying areas and places with poor drainage. Thunderstorms may also bring tornadoes, lightning and strong wind gusts.

Bao Anh