A tropical storm is intensifying and is expected to reach typhoon strength before hitting southern China's coast on Sunday.

Tropical storm Wipha weakened after making landfall in northern Vietnam on Tuesday, with authorities on alert due to heavy rains that could cause flooding and mudslides, as the Philippines struggled with monsoon downpours that began last week.

HANOI, Vietnam -- Vietnam braced for Typhoon Wipha on Monday as coastal provinces were placed on emergency alert and airlines canceled flights ahead of the storm’s expected landfall early Tuesday.