The Hue Civil Defence Command said on September 12 that emergency response measures were being accelerated to prepare for heavy rain, strong winds, coastal flooding and rough seas associated with the weather system.
According to officials, all 1,120 fishing vessels and 7,909 fishermen and crew members have been guided to safe anchorage areas.
Local authorities said maritime agencies continue to monitor developments at sea and are advising fishermen not to underestimate the risks posed by the tropical depression.
The Hue Hydro-Meteorological Station reported that a low-pressure system southwest of the Hoang Sa (Paracel) Islands strengthened into a tropical depression on the morning of September 12.
Forecasters expect the system to continue moving west-northwest over the next 24 to 48 hours.
Weather officials warned that waters between Ha Tinh Province and Quang Ngai Province could experience force-6 winds, gusting to force 8, with waves reaching two to four metres. Vessels operating in the area face heightened risks from thunderstorms, waterspouts, strong winds and rough seas.
Onshore, central Vietnam has already experienced several days of heavy rainfall.
From the evening of September 10 to the morning of September 12, many areas recorded between 150mm and 170mm of rain. Particularly high totals were reported at Bach Ma Mountain, which received nearly 400mm, while Phong Dien recorded more than 212mm and Khe Tre exceeded 202mm.
Meteorologists forecast further heavy to very heavy rainfall across Hue through September 15.
Rainfall totals of between 70mm and 150mm are expected on September 12 and 13, with some locations likely to receive more than 250mm.
Authorities have warned of a high risk of urban flooding, flash floods and landslides in mountainous areas, as well as storm surges and large waves near river mouths and along coastal zones.
Emergency services remain on alert as the tropical depression continues its approach toward Vietnam's central coastline.