Good Day Adam.
I got curious about this whole Hurricane "Category" rating scheme. In my opinion it's as useful as a car's Check Engine light. Except there are five lights, labeled 1 thru 5. And the owner's manual says for 5, "Get out of the car and run as fast as you can. It's about to explode!"
Do the EVs even have engines to check?
So here's the dirt on those nonsense numbers. They might as well be Categories "A - E", like the old Disney Parks' ride grading system, for ticket costs. Sorry, it's long because it's "technical".
It was first introduced by a wind engineer (Herbert Saffir) and a meteorologist (Robert Simpson) in 2010. That's why it's called the Saffir-Simpson Hurricane Wind Scale, or SSHWS. Previously, it was SSHS (missing the "W" word). Was that also a snub of George H W Bush?
A previously used system of classifying Atlantic and Pacific storm severity, had more data than just wind speed. Because, they couldn't reliably determine a storm's wind speeds by aircraft. So they used other data, to gauge it's strength, out at sea.
But I guess it was too confusing to the general public, to tell them about storm surge, water temperature, air pressure, etc. So they dumbed it down (thanks, to Robert "Homer" Simpson) to a simplified range of Cardinal numbers. Based only on the Wind speeds.
This scale that was first created by Herbert Saffir, who worked for the U.N. in 1969, to study low-cost housing in hurricane prone areas. While conducting that study, Saffir realized (or UN dictated) that there was no simple means to scare the shit out of the lay-people. So this scale was devised, based on the subjective MSK-64 scale of earthquake damage, and the objective Richter scale of earthquake intensity.
Back then it was called the "Proposed Hurricane Damage Scale (UN 1974)". Based on 2-3 seconds of peak wind gusts, and subjective levels of structural damage. So it was not a "live" storm strength scale, but used for afterward, property damage blaming. And it used "Grades" (1-5), in increments of 30 km/h, starting at 120 km/h (Grade 1) up to 241+ km/h (Grade 5). And nothing for pre-Grade 1 storms.
Saffir submitted this scale to the NHC, where Simpson changed its "Grades" to "Categories". The wind gusts of 2-3 seconds, changed to 1 minute sustained wind speeds. And he added storm surge, and barometric pressure (1st published 1975). In 2009, the NHC eliminated the air pressure and storm surge data from the five categories.
Now called the Saffir-Simpson Hurricane Wind Scale (Experimental), the updated scale became operational on May 15, 2010. So all the past Hurricane "Grades" or "CATs", are nearly meaningless, comparing them to the 2010 scale. Which was again changed in 2012.*
[https://en.wikipedia.org/wiki/Saffir-Simpson_scale](https://en.wikipedia.org/wiki/Saffir-Simpson_scale)
According to the updated* 2012 SSHWS:
A Tropical Depression ("D") storm is anything with winds below 39 MPH. A Tropical Storm ("S") is anything with winds from 39 to 74 MPH. That's a "36" wide range, on top of the Depression's range. But one can't really count winds less than 5 MPH. So the Depression range width isn't really "38". Maybe only "28".
A Tropical Depression is just whatever builds up to 38 MPH, but doesn't go over. Sort of a meteorological gray area. Any winds above the Tropical Storm upper limit (73 MPH), lasting for one minute, and the "Category" hurricane scale starts, and storms get people names.
This year, #2 was "Beryl", and #13 is "Milton". Milton Beryl? Did they think nobody would catch that "joke"? And did Beryl "steal" that one, too? Anyway....
A Cat~1 storm is 74 to 95 MPH, that's a "22" wide range. A Cat~2 storm is 96 to 110 MPH, that's a "15" wide range (why 7 less?). A Cat~3 (labeled Major) storm is 111 to 129 MPH, that's a "19" wide range. So why can't the 1st four Cat.s be the same "21" wide? The English to Metric rounding error, defense? I don't buy it.
As you can see, the SSWHS scale favors a quicker Category progression, by making Cat~3 easier to reach, with Cat~2 & 3 weighted as narrower ranges to get thru. Then comes Cat~4's wind speeds.
A Cat~4 storm is 130 to 156 MPH*, that's a whopping "27" wide range. Much wider than the prior three ranges of wind speeds. So Storms can more easily become a Cat~4, and stay within there, for the propaganda records.
A Cat~5 storm is just anything that is 157 MPH and above. One can't calculate its range width, with no top end defined. So whatever wind speed any Cat~5 has ever been the strongest recorded, make that the possible top end of a Cat~5. And I bet its range width is less than the Cat~4's.
Hollywood (aka Norman Lear & CBS-TV) likes to make up propaganda about the weather/climate, so they invented a "Cat~6" (and later a "Cat~7"), as their "Doomsday" number(s). Just letting you know, that's not real. CBS Was 6 years ahead of official SSWHS numbers, and doesn't apply to Tornadoes, anyway! CBS/Lear were WRONG!!
[https://en.wikipedia.org/wiki/Category_6:_Day_of_Destruction](https://en.wikipedia.org/wiki/Category_6:_Day_of_Destruction)
* In 2012 the SSHWS was "updated". The excuse was that conversion between English and Metric (MPH To Km/H) caused a "rounding off" error. That on rare occasion, shifted a Cat~4, to a Cat~3. Or even more rarely, to a Cat~5. So in order to fix that, they widened the Cat~4 range, by adding 1 MPH at each end. It use to be 131 to 155 MPH (a 25 wide range). And they shrunk the Cat~3's top speed from 130 MPH, down to 129 MPH. Narrowing its range, from "20", to "19".
They claim that this update doesn't change any Hurricane classifications, on record prior to 2012 (three years worth?). And further claim this update won't change future Hurricane classifications. But I can't possibly see how it couldn't change them. Maybe just 2012's storm season, wasn't. But 2013 and so on, must be.
So the obtainment of more Cat~4 storms, isn't strickly a matter of warmer waters. But Also changing the Category 4 wind speed definition, to a lower number. And widening its speed range from "25" to "27". Shorting Cat~5 a tiny bit (but who cares). And Cat~3 also gets robbed 1 MPH, of its upper limit and range. Nice, huh?
Just to fix a math error, caused by converting English and Metric scales?! This shows how meaningless the Categories are now, and were before. That this error wasn't discovered back in 2010, and remedied before Hurricanes got recorded as Cat~3 or 4, in the Atlantic and Pacific oceans?
This scale was adopted after "Barry S." became POTUS. And it makes Climate Change look worse, by these new numbers. That only goes back to 2009, at the earliest?
I attached two PDF about SSWHS definitions and that 2012 update.
Later, Glenn
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