According to the National Centre for Hydro-Meteorological Forecasting, At 7 am, Noul was packing sustained winds of 62-74 kph, with gusts of up to 102 kph, and was located about 210 km east of Luzon Island in the Philippines.
The storm is forecast to enter the northeastern East Sea late on Friday or early Saturday before making landfall in China's Guangdong Province on July 26, with an 80 per cent probability, and is unlikely to directly affect Vietnam's mainland.
Noul is forecast to strengthen to the equivalent of Beaufort force 10-11, with gusts reaching force 13.
From Friday evening, winds over the northeastern East Sea are forecast to strengthen to Beaufort force 8-9, reaching force 10-11 with gusts to force 13 near the storm's centre. Waves could reach 4-6 metres, with very rough seas.
The weather agency warned that vessels operating in affected waters could face thunderstorms, squalls, strong winds and high waves.
Separately, northern Vietnam is forecast to receive a further 40-100 mm of rain through July 25, with isolated totals above 200 mm, after some areas recorded more than 120 mm overnight. The downpours could trigger flash floods, landslides and flooding in low-lying areas.
