The Southern Regional Hydrometeorological Centre forecast cloudy skies with scattered showers and thunderstorms across HCM City and southern provinces on November 7.
Temperatures are expected to range from 23 to 34 degrees Celsius.
Forecasters said developing weather disturbances would bring more frequent thunderstorms than on November 6, with an increased likelihood of moderate to heavy rain in the late afternoon and evening.
In HCM City, heavy rain combined with rising tides during the early tenth lunar month could cause flooding in low-lying and riverside areas, disrupting daily activities and travel.
At sea, the strengthening northeast monsoon is expected to bring unsettled conditions off southern Vietnam and Lam Dong, posing risks to fishing vessels and other boats.
Scattered showers and thunderstorms are forecast over coastal waters, with the possibility of strong gusts and waterspouts.
Northeasterly winds off the coast from Lam Dong to HCM City are expected to reach Beaufort force 5, occasionally force 6, with gusts of force 7-8.
Waters from HCM City to Ca Mau will experience northeasterly winds of force 4-5, occasionally force 6, while east-northeasterly winds of force 4-5 are forecast between Ca Mau and An Giang.
Forecasters warned that moderate to strong northeasterly winds off southeastern Vietnam and Lam Dong could make conditions hazardous for small vessels and disrupt coastal and island tourism over the weekend.