Typhoon weakens, but heavy rain threat persists

Typhoon Dolphin has weakened to a tropical storm after making two landfalls in eastern China's Zhejiang province, but its moisture-rich circulation is continuing to move northwestward, threatening to unleash potentially extreme rainfall across parts of northern China, meteorologists said on Monday.

Dolphin, the 13th typhoon of the year, made two landfalls in Zhejiang on Sunday evening and weakened as it moved inland. But unlike many tropical cyclones that rapidly dissipate after landfall, its extensive cloud system and abundant moisture have allowed its remnants to persist and move northward and westward, said Zhang Fanghua, chief forecaster at the National Meteorological Center.

"The residual circulation could bring persistent and extreme rainfall to parts of eastern and northern China," Zhang said.

Dolphin's movement is forecast to significantly slow after Tuesday, and around Wednesday its remnants could stall near the border area of Hubei, Henan and Anhui provinces.

The residual vortex is expected to interact with an upper-level trough in the westerlies and a cold-air system, potentially triggering a new round of widespread and heavy rainfall, Zhang added.

The heavy rain will cover much of Shanghai as well as Zhejiang, Jiangsu, Anhui, Hubei, Henan and Shan­dong provinces through Tuesday.

As the rain belt moves northward on Tuesday and Wednesday, some locations in Henan, Hebei, and Shanxi could receive 400 to 600 millimeters of rain, with the possibility of exceptionally heavy downpours.

Meteorologists warned that the threat will also extend into the Beijing-Tianjin-Hebei region.

Zhai Liang, chief forecaster at the Beijing Meteorological Service, said that warm and humid air from Dolphin's outer circulation, combined with cold air, is expected to bring heavy rain to the region from Tuesday through Thursday.

"Beijing is expected to receive the strongest rainfall from early Wednesday to Wednesday night," Zhai said, adding that red alerts for heavy rain have been issued in districts such as Fangshan, Daxing, Tongzhou and Mentougou.

On Monday, the National Meteorological Center continued to issue an orange alert for heavy rain, the second-highest warning level. Isolated areas in northern Hubei could receive 250 to 270 mm during the 24-hour period between Monday afternoon and Tuesday afternoon.

The Ministry of Emergency Management has activated a Level IV flood-control emergency response in Hebei, Henan, Hubei and Shandong amid rising risks of flooding and geological disasters over the next three days. China has a four-tier emergency response system for flood control, with Level I being the most severe.

Local governments are being urged to closely monitor updated weather forecasts and strengthen preparations for flooding, landslides, mudslides and urban waterlogging, particularly in mountainous areas and along rivers.

The Ministry of Agriculture and Rural Affairs on Monday renewed a warning over the risk of farmland waterlogging. From Monday night through Saturday, parts of Henan could see exceptionally heavy rain, with a very high risk of farmland waterlogging. The prolonged rainfall could leave farmland saturated and affect crop growth.

Farmers are advised to clear drainage channels, as well as prepare pumps and other equipment and supplies in advance. After the rain, farmers should promptly drain excess water, improve soil aeration and moisture conditions, and use pesticides and fertilizers to help crops recover and resume their growth.

After Thursday, the rainfall pattern is expected to shift as the residual vortex gradually moves eastward and southward, forecasters said. If the residual vortex redevelops around Aug 16, it could bring another round of heavy rainfall to northeastern China, they added.

zhaoyimeng@chinadaily.com.cn