Typhoon Muifa forecast to hit Shanghai
Typhoon Muifa is poised to hit Shanghai, China’s most populous metropolitan area, late Wednesday night into Thursday morning local time, unleashing torrential rain and the potential for damaging winds and a disruptive ocean surge.
The storm is expected to make landfall with 80 mph sustained winds, the equivalent of a Category 1 hurricane.
The Chinese Meteorological Administration has hoisted orange warnings in advance of the typhoon’s anticipated arrival, writing: “[a] heavy rain or rainstorm will wallop coastal regions.”
The agency also cautioned that “coastal regions … will be exposed to [a] scale 6-8 gale,” which corresponds to sustained winds of up to 46 mph. That’s a broad warning for a lengthy stretch of coastline, however, and more severe warnings likely will be issued when it becomes clear where exactly the storm center crosses the coast. Gusts areawide are expected to top 60 mph.
Al Jazeera reported that officials in Shanghai, home to nearly 40 million people, had plans to cease port operations on Wednesday, with some projects wrapping up early, on Tuesday evening. More than 7,000 vessels have sought safe harbor in the ports. Schools were also asked to close.
Meteorological officials are in “emergency” mode, which requires forecasters to “put timely and precise forecast and refined services for the government, related sector and the public in place.”
The storm already reportedly dropped 13.9 inches of rain on Hateruma Island in Japan.
On Tuesday evening local time, the center of Typhoon Muifa was located near 26.8 degrees north latitude, 123.9 degrees east longitude. That places it about 150 miles northeast of Taipei, in the East China Sea, or midway between Okinawa and coastal Zhejiang province in China.
According to the U.S. Joint Typhoon Warning Center, maximum sustained winds in the core of the storm were just shy of 105 mph, which makes Muifa the equivalent of a Category 2 hurricane.
On satellite, it appeared the northern outer rain bands of Muifa’s circulation were thinning some, but that’s likely due to a restructuring as it organizes. Water vapor satellite imagery shows evidence of robust moisture to the storm’s north, meaning this isn’t a case of dry air entrainment eroding the storm’s periphery.
Thunderstorm activity can be seen roiling aggressively as individual updraft towers orbit the storm’s center. That’s usually a sign of strengthening, and Muifa is expected to slightly intensify before weakening some on final approach to China.
As currently forecast, Muifa is predicted to move into Hangzhou Bay, south of Shanghai, during the mid-evening hours local time Wednesday. From there, the storm will continue north-northwest toward the heart of Shanghai’s urban corridor.
The Joint Typhoon Warning Center projects maximum sustained winds of around 80 mph, primarily east of the center, with winds in the 55 to 65 mph range to the west. Winds may be accelerated in between the city’s tall buildings.
The specific track will be key when it comes to storm surge: the rise in ocean water above normally dry land. Tropical cyclones and all low-pressure systems in the northern hemisphere spin counterclockwise, which results in southerly winds on the eastern side of the system but northerly winds on the storm’s west. Given the shape of Hangzhou Bay, an onshore flow could push significant amounts of water toward coastal stretches of Pudong and the Fengxian district. That could spell a storm surge on the order of 4 to 6 feet in a reasonable worst-case scenario. Sea walls are common in those parts of the city, but splashover and some inundation are still likely.
A potentially greater concern will stem from the Yangtze River and the Changjiang River estuary, which is oriented northwest to southeast. Assuming winds begin as southeasterly, that will push water inland, possibly spilling over into areas like the Bixi Residential District or coastal Nantong.
Any flooding could be made worse by expected rainfall, since a backed-up Yangtze would mean reduced ability for freshwater flooding to drain into the ocean. As it stands now, the Chinese Meteorological Administration is forecasting up to 10 to 16 inches of rainfall in the region, and rainfall rates could top 2 to 3 inches per hour. That could pose an issue for the city’s subway system.
Shanghai is no stranger to tropical systems. Last year, Typhoon In-fa struck just south of the city, leaving behind the equivalent of $2 billion in damage in China.
In July 1915, the strongest typhoon to strike the city delivered sustained winds of 85.7 mph. This typhoon is unlikely to be as intense. In 1949, Gloria passed just south of Hangzhou Bay as a Category 2-equivalent typhoon.
Another developing tropical system could threaten part of the Japanese Archipelago and East China Sea next week.