Neil, excellent post - and even I understood it.
Very helpful infoOriginally Posted by Neil
I was wondering if you have any pics of these measuring devices?
So are you saying that this would have worked better if the wind was 180+ ?Originally Posted by edog2007
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It would be a BLAST!!!!Originally Posted by mtruman
Thanks for all that info Neil. That actually answered several questions I have had for a while and always forget to ask Ken...assuming he knows the answers.Originally Posted by Neil
Nothing has changed in the sense that there still isn't an automated process in place to determine the "real wind". This wind event has certainly opened up a can of worms regarding that subject.Originally Posted by Neil
No worries. You're right, it is much easier just to tell them the gust was 182. The majority of the people on our tours in the summer probably wouldn't care to hear that entire explanation anyways. Afterall, it is only a 2% difference.Originally Posted by Neil
As Neil pointed out, wind speeds/gusts measured by the Setra pressure transducer are not corrected for temperature and pressure. Therefore, the 148.5 mph gust is not entirely accurate considering the actual temperature and pressure outside at the time the wind gust was measured.
I was unable to use the Setra to calculate the corrected wind gust because we only save the high resolution differential pressure data used by our computer database to calculate that gust for 20 minutes. So, the Barton high speed wind chart had to be used to calculate it.
So after running through the proper calculations, the official corrected wind gust is.....(drum roll please).....
That also means that my buddy Mr. Jim is not the winner of this contest. It is actually WSR88D with a guess of 138 mph. And no Jim, you can't argue that your guess was for the uncorrected wind gust. You should have known from that start that 148.5 was uncorrected Perhaps in the future it will be best to specify that guesses are for CORRECTED gusts.
Look for a more detailed writeup about this in the observer comments at some point later today.
Last edited by bclark; 03-27-2008 at 01:36 PM.
Originally Posted by bclark
Oh you guys and your new math...I'm only calabrated to compute data the uncorrected way...
Congrats to WSR88D
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137 versus 149? That's not a trivial difference.
I'm going to ponder the ramifications of this. In general should I look at the MWO wind data and think that speed is within 10% of the actual number?
Next up: Vermont City Marathon: May, 2011
I agree that it is not a trivial difference, however I also wouldn't call it a significant difference. Afterall, it is "only' an 8% correction.Originally Posted by Bill O
Absolutely not.Originally Posted by Bill O
First of all, the correction curve is not linear by any means. A lower wind speed at the exact same temperature and pressure as this most current big gust would not have as big of a correction. For instance, a gust of 101 mph under the same conditions as this gust, recorded by the Barton chart(4.25 inches of displaced water column) would only need a trivial 2% correction to 99 mph.
Additionally, different temperatures and pressures will cause big changes in the correction. I will get into this more in the observer comment I am working on, but I will explain briefly here. The Barton high speed wind chart was calibrated for a temperature of 27 degrees F, according to my boss Ken. I would assume it was calibrated to a "standard pressure" of 800 millibars. The closer the outdoor temperature and pressure is to these values at the time the wind is measured, the more accurate the uncorrected value will be. For this instance, the Barton read 8.125 inches of water, which roughly equates to 140 mph. That means that 137 mph is only a 2% correction. Again, this is small enough to consider trivial in my book.
The Setra pressure transducer, the device used to measure the 148.5 mph gust, works slightly differently. That will be explained in the observer comment.