The agency said the storm was expected to move mainly westward over the next 24 hours at a speed of 5-10 kph before turning west-northwest under the influence of a subtropical high-pressure ridge.
Forecasters said the system was unlikely to cross the Philippines and move into the East Sea, with the probability estimated at below 20 per cent.
The agency said a subtropical ridge currently persisting over the East Sea at an altitude of around 5,000 metres was expected to block the storm’s path towards Vietnamese waters.
Hagupit is forecast to strengthen to Category 10 on Vietnam’s storm intensity scale before weakening into a tropical depression near waters east of the Philippines, the agency said.
However, forecasts beyond the next two days remain uncertain as weather models continue to show differing scenarios, it added.
Earlier on Wednesday, a tropical depression over the northwestern Pacific strengthened into Typhoon Hagupit, following Super Typhoon Sinlaku.
Hagupit is the fifth storm to form over the northwestern Pacific during the 2026 typhoon season.
At 1 pm on May 6, the storm’s centre was located at 8.4 degrees north latitude and 147.3 degrees east longitude, with maximum sustained winds of Force 8 and gusts up to Force 10. The storm was nearly 2,000 kilometres east of the Philippines.
