In a scenario not so unlike Hurricane Harvey over Texas in 2017, a powerful hurricane is stalling over a populated area, dropping copious amounts of rain and prolonging damage from unrelenting winds.
But after Hurricane Dorian spent several days approaching the Bahamas and Florida at a forward speed of 5-10 miles per hour, why did the storm sit still for more than 24 hours?
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Hurricanes are extremely powerful, but also very sensitive to the environment around them. Think of holding a balloon in your backyard, then releasing it up into the sky. The balloon will rise, but also move left or right as “steering winds” push it one direction or another.
Late last week into the start of Labor Day weekend, the clockwise flow around a ridge of high pressure over the Atlantic was steering Hurricane Dorian closer to the U.S.
On Sunday however, those steering winds collapsed and the storm’s forward speed slowed to 0 mph.
Dorian is currently too far from any other large-scale weather systems that would push or pull the hurricane. High pressure over the Four Corners is not influencing the system, nor is the jet stream over the northeastern U.S.
As of 7 a.m. this morning, a very slow northwestward motion is resuming. This evening and Wednesday, the jet stream to the north of Dorian is expected to dip southward, closer to the hurricane. This should induce then accelerate a northward motion, skimming the southeast coast of the U.S. with hurricane-force winds, storm system and heavy rain.
Hurricane Dorian has been a historic storm, and the name will surely be retired from future use. See two of Dorian’s most impressive records below, courtesy of Philip Klotzbach from Colorado State University:
- Strongest hurricane on record to hit the Bahamas (by minimum pressure)
- 2nd-strongest Atlantic hurricane on record (by wind speed)