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Laura Only Ranks 17th For Minimum Pressure

August 31, 2020

By Paul Homewood

Hurricane Laura

Hurricane Laura

Much has been reported about Hurricane Laura’s wind speeds of 130 Kts at landfall, which if true would make it the fifth most powerful hurricane at landfall to hit the US, tied with five others:

image

https://www.aoml.noaa.gov/hrd/hurdat/All_U.S._Hurricanes.html

However atmospheric pressure tells a rather different story. When Laura made landfall, the minimum pressure recorded was 938 mb. This would rank it as only tie 17th strongest.

image

https://www.aoml.noaa.gov/hrd-faq/#most-intense-hurricanes

Atmospheric pressure does not always precisely correlate with wind speeds, as surrounding air pressure can be a factor. Also smaller hurricanes, such as Labor Day and Andrew tend to have higher wind speeds, as the isobars are more tightly packed.

Nevertheless, none of these factors seem to have been relevant with Laura. Given the ways that wind speeds are measured have changed over the years, atmospheric pressure should always be regarded as a more accurate comparison of a hurricane’s strength. Indeed, pressure is the main way in which windspeeds have been measured in the past, when there was little ground data available.

Laura may have had wind speeds of 130 Kts, as claimed. But the logic suggests many more storms had higher wind speeds in the past than the official records show.

16 Comments
  1. August 31, 2020 5:52 pm

    Punishing, but no prize winner. Pressure is a better metric for hurricanes, as suggested.

  2. Gamecock permalink
    August 31, 2020 6:23 pm

    It was just a hurricane. We get them every year.

    • September 1, 2020 11:54 am

      I remember when Hugo went through South Carolina and flattened a good portion of the Francis Marion Forest. The SC botanists were wringing their hands that there would be no herbaceous plants. Ahem. The next year at the Association of Southeastern Biologists’ meeting, the very same people were crowing about how many wildflowers they had seen. Some were previously unknown the the state flora, having been suppressed by the heavy forest canopy.

      • Harry Davidson permalink
        September 1, 2020 5:43 pm

        Hurricane Michael is the strange one. Allegedly Cat 5, the storm surge swept away the houses on stilts and the clapper board stuff on the sea front, but the modern building codes houses behind were completely untouched. One house had a small section of roof torn back was all they could find. Not a single broken window.

        The lack damage was entirely inconsistent with the wind speeds claimed. The storm surge apparently struggled to do more that get up the beach. If it had gone over the houses at the back, as a 20′ surge would have, there would have been huge amounts of damage. A storm surge has all manner of junk in it, it breaks windows.

  3. August 31, 2020 11:08 pm

    BBC Activist TV
    9pm on Tue 1 Sep, @HughFW & @itsanitarani are on @BBCOne
    with The War On Plastic: The Fight Goes On
    https://bbc.co.uk/programmes/m000m82c

    • Ben Vorlich permalink
      September 1, 2020 3:35 pm

      Are these people who are waging war on plastic actually managing without?

  4. September 1, 2020 1:13 am

    Face it. Laura was a media hype that died on the vine!

  5. Nancy & John Hultquist permalink
    September 1, 2020 2:31 am

    Some hype is to be expected. The details are important.
    For those that had their houses scattered over the landscape, Laura was a serious catastrophe. Last count of deaths is 19. Some by trees. One fell on a guy trying to cut it out. Half died from unsafe operation of generators – carbon monoxide poisoning.
    A summary to this point is here: ABC News with an Associated Press story

    Use this “damage Hurricane Laura” with an images search-up.

  6. dave permalink
    September 1, 2020 8:35 am

    Globally, the first eight months of 2020 have been extraordinarily calm:

    http://climatlas.com/tropical/

    Of course sod’s law will now strike me down, I am sure!

    I have the impression that ordinary Americans are less impressed than Britons by trivial, irrelevant, records, like the maximum wind at a particular spot at a particular time. Am I right about this?

    • Nancy & John Hultquist permalink
      September 1, 2020 3:40 pm

      Ans: Generally speaking, yes. Response might be “Wow!” and then a new thing enters their mind.

      ordinary Americans

      . . . that bother to watch or listen to the main media don’t have a perspective for these weather records. If asked about the highest recorded temperature in their town – they would not know. (I know the highest and lowest that I’ve experienced, and where; but the records for the current town – don’t know.) Nor could they tell you whether Lake Charles was nearer Miami or Houston.

      Clearly, they are not reading Paul Homewood’s excellent accounts of such events.

  7. September 1, 2020 9:56 am

    With lower UK national grid demand this year (COVID-19) and with two named storms during August driving even more wind turbines isn’t it encouraging to think about the reduction in natural gas burned during August. There’s been less CO2 released into the atmosphere and more NG kept in the ground for future generations to utilise as a backup to renewable generation.
    Except that with the monthly figures now in NG power averaged at 12.05GW through August 2020 compared with 9.7GW Aug 2019. Doh!

  8. September 1, 2020 10:27 am

    Sorry but turbines have to be braked during high winds – too dangerous. Blade throw is the most common problem with these things and they can travel long distances. For turbines to generate the wind speed has to be not too high or too low (or nothing). If it’s optimum speed for too long they still have to be braked to avoid problems for the Grid.

    • September 1, 2020 1:11 pm

      Never mind, there’s usually a hefty handout for doing the Grid a ‘favour’.

    • Ben Vorlich permalink
      September 1, 2020 3:40 pm

      Goldilocks scenario, not too fast, not too slow the wind speed has to be justvright

  9. Gerry, England permalink
    September 1, 2020 11:06 am

    WUWT has a good look at the windspeeds of Laura where both the constant windspeed and the gust speed are looked at. when using the Saffir-Simpson scale it is only constant speed that is used for the category and from the data Laura was only a category 2 on landfall. But anyone with a wobbly fence knows that it is the gusts that get you and what does the damage. There is also a look at friction which is why once a hurricane hits land the speeds drop.

  10. MrGrimNasty permalink
    September 1, 2020 12:27 pm

    Mean CET Summer 2020:-

    As I (flukily) predicted from the long-term forecast, which for once didn’t change drastically, Aug 2020 ended up the same as Aug 1976, joint ranked 12-19 with 7 other years of 362, 1.6C cooler than the hottest Aug 1995.

    The summer only joint ranked 51-56 with 5 other years, 1.6C cooler than the hottest 1976.

    We are still on for a record yearly CET, only has to be about 1.1C above 1961-1990 average for the remaining months, which every month apart from Mar and Jul have been this year.

    Sea Ice:-

    After appearing to be falling, the DMI Arctic daily mean temperature above the 80th northern parallel are strangely reluctant to dip below 0C, very late. Very low ice extent/volume but by no significant margin over recent years, looks like it has probably bottomed out.

    Conversely Antarctic ice continues to shoot up into the higher reaches of normal for the time of year.

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