Jeff Masters -Meranti Approaches China Coast After Sweeping Past Taiwan

[malaise]

https://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=3429
<snip>
One of the strongest tropical cyclones in modern weather history, Typhoon Meranti, was approaching the southeast China coast late Wednesday night local time (Wednesday afternoon EDT). As of 16Z (noon EDT), Meranti was located by the Japan Meteorological Agency near 23.8°N, 118.6°E, or about 50 miles southeast of the coastal city of Xiamen in China’s Fujian province. On its steady northwest track at about 12 mph, Meranti should make landfall near or just south of Xiamen at around 4 pm EDT.

Meranti tracked just south of Taiwan’s mountainous south end over the last 24 hours, which disrupted its circulation and put a huge dent in its top sustained winds. You can see the weakening of the typhoon as it passed by Taiwan on this long radar loop from Taiwan compiled by Brian McNoldy. At noon EDT Wednesday, Meranti’s 10-minute average winds were down to 105 mph, according to JMA. The 1-minute average wind used by U.S. agencies is typically around 14% greater than the 10-minute average, so the JMA value would correspond roughly to a 115-mph low-end Category 3 hurricane. Meranti could weaken a bit further before landfall.

In spite of its decline, Meranti retains the potential to produce a major storm surge along the China coast. It takes some time for the huge amounts of water being pushed by a major hurricane or typhoon to subside, even after the storm itself weakens. Two good examples are Hurricane Katrina and Hurricane/Superstorm Sandy, both of which produced catastrophic storm surge despite significant weakening of their top winds in the hours before landfall. Meranti’s surge would be worst just to the north of its center, and this part of the storm is aimed at the city of Xiamen (population 3.5 million), one of the world’s 20 busiest ports for container shipping. Because China’s coast is so densely populated, storm surge can threaten huge numbers of people. In 1994, Typhoon Fred struck the province of Zhejiang after weakening from a Category 4 to a Category 1 storm. Fred still managed to produce a top surge of just under 9 feet that affected more than 22 million people, as noted by storm surge expert Hal Needham.

Torrential rains are another serious threat from Meranti across east central China. Widespread 3” - 6” rains can be expected near the typhoon’s track as it moves inland, with localized 10” - 15” amounts quite possible. The heavy rain may extend further north later this week, toward Shanghai, as Meranti’s remnants are swept northward. In 1983, Typhoon Wayne followed a very similar track to Meranti, passing just south of Taiwan and weakening from a Category 4 to Category 1 before landfall several dozen miles south of Xiamen. Coastal and inland flooding linked to Wayne in Fujian and Guangdong provinces led to 105 deaths and the collapse of some 30,000 structures.