SHANGHAI, Aug. 9 (Xinhua) -- China's eastern metropolis Shanghai issued its highest rainstorm alert Sunday over rising risks of urban waterlogging brought by Typhoon Dolphin, the 13th typhoon of the year that has a great impact on the country's coastal regions.

At 10:30 a.m., the Shanghai Meteorological Observatory upgraded the rainstorm alert to red, the top rank in China's four-color warning system. It predicted accumulated rainfall would exceed 220 millimeters across most downtown zones in the following six hours.

The intense downpours pose high risks of urban waterlogging and severe traffic gridlock. In response, Shanghai Flood Control Headquarters raised the downtown flood-and-typhoon emergency response from Level III to Level II.

People in low-lying areas are reminded to stay alert and take precautions, as rain is forecast to blanket most parts of Shanghai from Sunday to Monday. Waterlogging between 0.3 and 0.5 meters could hit low-lying lots, road underpasses and flood-prone spots in several suburban districts.

Shanghai is also expected to see a peak tide level on the Suzhou estuary of Huangpu River reaching as high as about 4.6 meters at 10:45 p.m. Sunday and 11:35 p.m. Monday.

Three metro lines in the city -- Line 5, Line 16 and Pujiang Line -- were suspended starting from 3 p.m. Sunday, while Line 3 was run at reduced speed across its entire route.

In adjacent Zhejiang, the provincial meteorological observatory estimated that Typhoon Dolphin was located at roughly 138 kilometers southeast of Wenling, Zhejiang at 11:00 a.m. Sunday, and it was moving westward at 20 to 25 kilometers per hour, with steady intensity as it drew nearer to Zhejiang's coastline.

The observatory forecast it would make landfall along the coast around Sunday evening to the early hours of Monday. After landing, the typhoon will shift slowly west-northwest and weaken gradually.

Since 8:00 a.m. Sunday, heavy downpours have hit several cities in Zhejiang, including Huzhou, Hangzhou and Ningbo.

On Saturday, the entry-exit border checkpoint in Zhoushan City, also in Zhejiang, opened a fast-track passage to allow 26 Chinese and foreign crew members onboard a Panamanian-flagged vessel to go ashore for shelter.

Liu Jiyuan, a police officer from the border checkpoint who took part in the operation, said the vessel carrying 35 crew members planned to dock at a wharf in Zhoushan for unloading. However, surging sea waves forced the ship to anchor temporarily.

The border police and the local maritime rescue force helped get 26 crew members from the vessel to go ashore for accommodation. Indonesian crew member Aceng Kusyaeri expressed gratitude for the timely assistance.

Zhejiang has activated the top-level typhoon emergency response since 8 p.m. Saturday. All coastal water passenger routes across Zhejiang had suspended services as of 4 p.m. Saturday, alongside 106 inland water passenger routes.

The Hangzhou Xiaoshan International Airport in the provincial capital of Hangzhou has canceled 196 inbound and outbound flights scheduled for Sunday. Lishui Airport in Lishui City canceled all 20 flights planned for the day.

Fuding, a coastal city in eastern Fujian Province, also faced severe typhoon threats, raising its local typhoon emergency response to Level I.

Forecasts from the municipal meteorological bureau show gusts may peak at around 37 meters per second on Monday. Several townships in the city face high risks of rain-triggered disasters.

At 9:00 a.m. Sunday, Fujian Province upgraded its typhoon emergency response to the second-highest level.