BEIJING, Aug. 18 (Xinhua) -- China's national observatory on Saturday continued to issue an alert for typhoon Rumbia and upgraded a rainstorm alert with some regions bracing for heavy downpours.

The National Meteorological Center (NMC) upgraded the rainstorm alert to the orange level as rainstorms will batter Henan, Hebei, Shandong, Anhui and Jiangsu provinces on Saturday and Sunday.

The country has a four-tier, color-coded weather warning system, with red representing the most severe, followed by orange, yellow and blue.

Affected by typhoon Rumbia, some parts of Henan, Hebei, and Shandong provinces are expected to experience downpours of up to 350 mm within 24 hours, according to the NMC forecast.

The observatory warned local authorities to take precautions against possible flooding and landslides.