For about three weeks, I've continued to hear a fair amount of German news media hype over climate change and the two hurricanes in the US. 'An absolute connection' is drilled down into each comment. Some of this....I find very amusing. The warm waters temperature business is typically the key phrase to use in this gimmick.
So, some simple observations, which one might use in a German moment with some naive natives.
1. A hurricane runs like a car. You start with 'Outflow'....these are the upper atmosphere clouds which move clockwise....OUT and away from the hurricane, generally up above 30,000 feet. The more....the better (more intense). Then you come to 'Feeder Bands'....these are bands of showers which go hand-in-hand with winds and rain. Here again....the more, the better (the more intense). It would help if the water temperatures were warmer. Then you come to the 'Eyewall'.....which is simply rows of clouds, winds and rain which build section after section after exiting the eye of the hurricane. Finally, you come to the last of the four components....the 'Eye'. This is where low pressure matters (where you get the big numbers which matter for intensity of the storm). The lower the pressure....the more intense of the storm. While sitting in the middle of the eye....you actually have this half-a-hour moment where you think peaceful and calm,and the 'Eyewall' appears and you realize that the 2nd half of the storm is about to arrive.
2. So at this point, you bring up wind shear. The environmentalist will be unhappy about the topic because you can't build a model to predict anything on wind shear. You can ask the model....if X occurs and this wind shear occurs at this point, what happens? But in a minute by minute situation.....wind shear is typically an unpredictable thing. In a matter of minutes....wind shear could occur and transform a category five hurricane into a four, and in a matter of another five minutes....drop it another notch. A big difference between a category three and five? Yes. Oh, you will still have some broken windows, possible flooding, etc....but the house will still be standing (if built with the newer standards of the past twenty years in Florida).
3. Flooding. Little gets hyped about the rainfall situation. In Texas....the general count was around 40-inches of rain. In Houston, the locals will tell you that even with four inches....there would be some minor flooding. At ten inches....it's a big deal. Hurricane Katrina upon Louisiana from twelve years ago? It brought only ten inches of rain to the area. In their case, it helped that they are below sea-level and their levy system is marginally fixed to handle maybe a limited amount of rain. Hurricane Donna (1960) dropped around a dozen inches of rain, which led to some flooding. The 1804 hurricane that set down up on New York in mid-October? It dropped around 30 inches of snow on the local area. You need particular conditions to get a hyped up rainfall. For Hurricane Irma in Florida....the max rain that came down was 16 inches in the Fort Pierce area.....while you find a number of areas which got ten inches or less. As Irma decreased in central and north Florida as it progressed....less rainfall occurred, and so less flooding was the result.
It's hard for German to grasp this with all the hyped-up science talk involved.....but you need absolutely perfect conditions to raise the stage up to a category five hurricane....that's why there are so few in a normal year (don't bother trying to say the past twelve non-hurricane years were normal). You might also want to remind the German that you could have a storm which goes over a seven day period from category one to category five, and then because of various conditions beyond water temperature (wind shear helps a lot).....you could slowly move back down to category one or less by the time it reaches mainland.
The key thing in this discussion with a German hyped up on climate change....you would need more than one component to reach a hurricane stage, and each of the components could flip and make this less of an issue or more of an issue. Warm water temperature alone....won't cut it.
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