Was Harvey a Cat 4 Hurricane?

Discussion in 'Tropical forum' started by Stan Rose, Sep 1, 2017.

  1. Stan Rose

    Stan Rose EF4

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    I haven't been able to answer this question looking online in the news, so I'll pose it here.
    Max wind gusts at landfall for Harvey from what I've seen were around 130 mph...most gusts were in the 100-110 mph range. Cat four requires *sustained* winds of at least 130 mph.
    Now, from the damage pics I've seen, looks certainly possible that there were pockets of sustained 130+ mph. And the central pressure could arguably give some support too. But it doesn't seem like anyone is asking the obvious question (although I stay out of the social media fray so maybe I've missed it...)
    So what am I missing?
     
  2. rdale

    rdale EF5

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    The sparsity of data networks means we rarely have direct obs at landfall. It seems almost always the NHC numbers are higher than any obs though. In the end, it probably doesn't matter, but until we line up sticks every 100 yards along the entire shoreline we'll never really know :)
     
  3. Jeff Duda

    Jeff Duda Resident meteorological expert
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    It's a good question. Rob already highlighted the issue with poor sampling. The highest gust reports I saw were in the 120-130 mph range, but those were gusts. As far as sustained winds, I don't know, but certainly lower than 120-130 mph.

    I think NHC does something similar to NWS local offices for tornado damage surveys and reviews all the information on a landfalling tropical cyclone after the fact, and will probably eventually write a detailed report on the storm that may not be ready for months yet. Hell, Andrew didn't get upgraded to category 5 until years after the storm.
     
  4. John Farley

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    I believe the DOW group Tim Marshall was with had a gust of 134 and another one over 140, but they were unsure about the accuracy of the latter. I also saw a report somewhere of 110 sustained, although IIRC that may have been a little above ground level.
     
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  5. Mark Blue

    Staff Member

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    I recall the upgrade to Cat 4 being issued not long before it made landfall. IIRC it was a direct result from readings the hurricane hunters observed, but I was watching TWC so take it with a grain of salt.
     
  6. Stan Rose

    Stan Rose EF4

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    thanks for the responses folks.
     
  7. JamesCaruso

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    I always wondered about that, why the NHC *sustained* wind speed numbers seem to be higher than even any reported *gusts* . I think this is part of the reason some people don't seem to fear and respect hurricanes and resist the call to evacuate. I guess sparsity of data sites has something to do with it, but does it explain it completely?


    Sent from my iPad using Tapatalk
     
  8. rdale

    rdale EF5

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    Remember FAR FAR more people die from water than from wind though. So don't get too caught up in it.
     
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  9. MClarkson

    MClarkson EF5

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    "Official" hurricane max winds are for open ocean. Sustained winds drop off dramatically over land. Also a lot of the samples from this storm look like they came out of the central or weak-side eyewall, with the stronger right eyewall less sampled. Given that, and the sparsity of surface obs previously mentioned, it looks like this forecast was in the right ballpark.
     

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