China's National Meteorological Center (NMC) said on Sunday morning that more rain is forecast for Zhouqu county in Northwest China's Gansu province over the next three days, possibly hampering the relief operation underway in the mudslide-hit region.

Thunderstorms and showers, with 1 to 5 millimeters of rain, are expected on Sunday in Zhouqu county and the Bailong River valley, which runs through the county.

The showers are expected to turn into rainstorms, with precipitation of up to 70 to 90 mms on Monday and Tuesday in Zhouqu county, according to a NMC weather forecast.

The mudslides in Zhouqu County have left at least 1,248 people dead and 496 others missing.

As for other parts of China, the NMC said downpours and hailstones would pound some areas in northern Chongqing municipality, southwestern Hubei province and northwestern Hunan province from Sunday to Tuesday.

Heavy rain will affect some areas of southern Gansu province, western Sichuan province, northern and southeastern Chongqing, central and southern Hubei province, northern and western Guizhou province, Yunnan province, coastal regions of southern China, Hainan province and southeastern Tibet, the NMC said.

Meanwhile, a searing heatwave is due to continue in China's southern regions from Sunday to Tuesday, the NMC said.

Over the next three days, high temperatures of 35 to 37 C will affect southeastern Sichuan province, Chongqing municipality, eastern areas of Guizhou and Hubei provinces, southern areas of Jiangsu and Anhui provinces, most areas in the lower reaches of the Yangtze River, and the central and northern parts of Guangdong province and the Guangxi Zhuang autonomous region.

The NMC warned that sweltering weather would bake southern Hunan province, central Jiangxi and Zhejiang provinces, and northern Fujian province from Sunday to Tuesday, with the mercury climbing above 40 C in some areas.