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Climate Change Drives Bigger, Wetter Storms -- Storms Like Florence (npr.org)
Rebecca Hersher, reporting for NPR: Hurricane Florence is moving relentlessly toward the Southeastern U.S. It's a large, powerful cyclone that will likely bring storm surge and high winds to coastal communities. But climate scientists say one of the biggest threats posed by Florence is rain. "Freshwater flooding poses the greatest risk to life," explains James Kossin, an atmospheric scientist for the National Oceanic and Atmospheric Administration and the University of Wisconsin, Madison. And Florence could cause extensive freshwater flooding for two reasons. First, Florence is moving slowly, and could all but stop when it reaches land. "The storm could be over North Carolina and traveling incredibly slowly -- on the order of just a few miles per hour," explains Kossin, who says an official from the city of Charlotte, N.C., contacted him about rainfall projections for that city.
If Florence stalls over the Southeast, it would be reminiscent of Hurricane Harvey, which spent days dumping rain on the Houston region last year. Some areas ended up with more than 60 inches, a catastrophic amount of water that shut down the entire region and resulted in at least 93 deaths. Slow-moving storms like Harvey are getting more common. A study published earlier this year by Kossin found that tropical cyclones around the world have slowed down 10 percent in the last 70 years. "We're seeing that in every ocean basin except the northern Indian Ocean," says Kossin, possibly because climate change is causing the wind currents that hurricanes ride to slow down. If Florence slows down and stalls when it hits land, it will the latest example of that trend. Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colo., says global warming also affects the size and intensity of storms like Florence.
If Florence stalls over the Southeast, it would be reminiscent of Hurricane Harvey, which spent days dumping rain on the Houston region last year. Some areas ended up with more than 60 inches, a catastrophic amount of water that shut down the entire region and resulted in at least 93 deaths. Slow-moving storms like Harvey are getting more common. A study published earlier this year by Kossin found that tropical cyclones around the world have slowed down 10 percent in the last 70 years. "We're seeing that in every ocean basin except the northern Indian Ocean," says Kossin, possibly because climate change is causing the wind currents that hurricanes ride to slow down. If Florence slows down and stalls when it hits land, it will the latest example of that trend. Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colo., says global warming also affects the size and intensity of storms like Florence.
The slow movement of Florence and possibility it stalls are not related to global warming to rather simply to the location of high pressure systems north of the storm preventing it from turning northward.
The size of the storm could be argued to be greater due to warming, but its a statistical discussion about averages over time, not one of any particular storm.
What drives storms? Temperature differences.
This is nonsense. Hurricanes are not driven by temperature differences between the tropics and temperate regions. They are driven by vertical differences in temperature and pressure.
Warm seas cause warm humid air near the surface. Warm air is lighter, and high humidity makes it lighter still. So it rises, creating a low pressure region, and drawing in more surface winds that pick up heat and humidity as they move to the center of the storm. When the air in the center rises, it spreads out and cools, condensing the humidity that falls as rain. The cooler dryer air then descends on the edge of the storm.
Warmer seas cause stronger storms. Cooler water weakens the storm as it travels north, the opposite of what you are claiming.
If the oceans were uniformly warm, would we still have hurricanes? Yes, and they would be stronger, bigger, and last longer.
I'm trying to figure this out....they're saying that global warming is going to cause this large storm to stall and dump rain?
I mean, it is moving about 15mph or so now, and is forecast to slow to like 3-7mph once it makes landfall....and somehow this slowdown is caused by global warming?
I mean, that is the reason they're worried about rain fall flooding.....
The effect of global warming in the Arctic is much greater than in the tropics (see Arctic amplification). This reduces the temperature differences going south to north which is one of the major drivers of wind. So the wind has slowed down which slows down the movement of weather phenomena embedded in the wind.
This study shows hurricanes have NOT increased in size (contrary to the title): https://www.wunderground.com/c...
"Tropical cyclone size does not appear to have changed significantly over the past 35 years."
Graph (it's a flat line): https://s.w-x.co/wu/storm-size...
"I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
Ok, here are a couple of non-Wikipedia sources on Arctic amplification:
Arctic amplification dominated by temperature feedbacks in contemporary climate models
Processes and impacts of Arctic amplification: A research synthesis