這篇美聯社的報導可以解釋多利安為何移動緩慢甚至幾近滯留，巴哈馬會受到重創也就不意外

Dorian isn’t moving because the upper atmosphere is too calm

簡單來說北方百幕達有一組高壓系統像一道牆擋住多利安北上，左邊向東移的低壓要把多利安推向北，兩組系統互相牽扯，多利安就像池塘紙船或鵝卵石無法移動

Usually the upper atmosphere’s winds push and pull hurricanes north or west or at least somewhere. They are so powerful that they dictate where these big storms go.

But the steering currents at 18,000 feet (5,486 meters) above ground have just ground to a halt. They are not moving, so neither is Dorian.

After reaching record-tying wind speeds on landfall in the Bahamas, the storm just stalled. Its eyewall first hit Grand Bahama Island Sunday night, and 18 hours later part of the eye still lingered there, meteorologists said. The hurricane center late Monday called the storm “stationary” after several hours of crawling at 1 mph (1.6 kph).

“This is unprecedented,” said Jeff Masters, meteorology director at Weather Underground who used to fly into hurricanes. “We’ve never had a Category 5 stall for so long in the Atlantic hurricane record.”

A high pressure system in Bermuda has been acting like a wall, keeping Dorian from heading north. But a low pressure trough moving east from the Midwest has eroded that high and is trying to pull Dorian north. Those two weather systems “are fighting it out and neither is winning,” Masters said.

Usually hurricanes that don’t move eventually kill themselves because they churn up colder water from deep below the surface and storms need warm water as fuel, Masters said.

“It’s got to keep moving,” Masters said.

大師還說通常颶風不移動會自殺，因為它們會攪動海底深層的海水，而颶風的養分是溫暖的海水

而巴哈馬群島和墨西哥灣流域是少數暖流如此深的地方之一，失速並不會像其它地方讓它死亡但威力會減弱

這對佛州和美國東岸有利，老美應該要好好幫巴哈馬重建才是，看了幾個太空人推文，從太空中看颶風的角度確實令人震懾



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