BEIJING -- China's national observatory Wednesday continued to issue a yellow alert for snowstorms, which are expected to blanket the country's central regions Wednesday and Thursday.

Parts of Shanxi, Shaanxi, Henan, Hubei and Anhui will expect heavy snowfall during the period, resulting in up to 20 mm of snow in some areas, the National Meteorological Center forecast.

The observatory advised residents to stay indoors and urged local authorities to take precautions regarding roads, railways, electricity and telecommunications.

It said central and eastern provinces could expect widespread rain or snow during the next 10 days, while temperatures in northwestern areas and regions along the Yellow and Huaihe rivers would drop.

In the country's four-tier warning system, red is the most severe weather, followed by orange, yellow and blue.