Wed AM Update:
Meranti passed near the southern tip of Taiwan, and apparently it was pretty windy and nasty there. But, Taiwan has invested heavily in infrastructure with the idea of being hit with giant typhoons now and then, so things were not as bad as they could have been.
apparently Meranti is now a category 5 equivalent heading for China. The storm is expected to weaken only a bit as it makes landfall (see this post on what landfall means) so this is going to be a direct hit by a major hurricane. There are some pretty densely populated areas in the storm's path. There are also many harbors that narrow quickly on the way into the elevated interior, where there is a very hilly terrain and some moderately restricted inland valleys. So, the prospects for major storm surges and serious inland flooding are significant.
Some time between late Tuesday and mid day Wednesday, the typhoon will have a run at the southern tip of Taiwan. This is the less populated part of the island, but this is a big storm and its effects will be felt over the entire country.
Interacting with Taiwan is not expected to slow down the storm too much, and some time late Thursday, possibly as a Category 3 equivalent, it will slam into China.
Then it will go inland and contribute significantly to flooding.
This is the strongest cyclone so far in this year's Northern Hemisphere season. Under climate change, we expect some cyclones to undergo much more rapid intensification, which can be a real problem when it occurs just before making landfall. This is the case with Meranti, though, as noted, the area to be affected initially is not as dense of a population zone as it might have been. The storm is stronger than it otherwise would have been had it not been for global warming, as well.
This is the less populated part of the island, but this is a big storm and its effects will be felt over the entire country.
As of Tuesday morning eastern US time (Tuesday evening in Taiwan), the error cone was big enough that Kaohsiung might get the right-hand eyewall. That's Taiwan's second largest city, population circa 3 million.
Most of Taiwan consists of mountainous terrain, so flash flooding and landslides are likely to be an issue. There is a tradeoff here: a bad hit on Taiwan will likely soften the blow on mainland China, while an offshore track for Taiwan will mean the storm remains relatively strong until near landfall on the China coast.
Super Typhoon Meranti has become the strongest cyclone, hurricane or typhoon, of 2016 and is one of three most powerful typhoons ever recorded. Typhoon Meranti wrought extensive damage across Fujian and Zhejiang provinces. In Fujian, the storm killed 18 people and left 11 others missing. Typhoon-force winds and flash floods caused tremendous damage, leaving more than ¥16.9 billion (US$2.6 billion) in economic losses.