A Severe Thunderstorm Warning for Heavy Rain is now in force for whole of Vanua Levu and southeastern parts of Viti Levu from Coral Coast through Suva up to Dawasamu.
The Nadi Weather Office says a trough of low pressure lies over the eastern parts of Fiji.
They say due to daytime heating, thunderstorms have formed over Vanua Levu, interior and southeastern parts of Viti Levu.
The Weather Office says these thunderstorms are expected to become severe and affect the areas.
Afternoon and evening thunderstorms are expected with heavy rainfall over the above mentioned area.
The Weather Office says severe thunderstorms are expected to produce heavy rain which may lead to flash-flooding of low-lying areas.
People are advised to keep clear of flooded creeks and drains, don't walk, ride bike or drive through flood waters, unplug computers and appliances, stay indoors away from windows and keep children indoors and stay vigilant and monitor conditions.