Why is Wind speed in hurricanes so wrong?



  • @Siff said in Why is Wind speed in hurricanes so wrong?:

    Yeah ok blame The President for this... Right...
    Technology that they use for satellite measurements is actually the GPS system and special x-ray detectors. The technology is already there and being used for this additional purpose. That is why I included the information about how they get the measurement data. GPS is already being used extensively and the resultant reflection off of the water let them calculate the movement of said water. The GPS signal is reused for this purpose. Now you are trying to tell me they are getting rid of the GPS system? I highly doubt that.
    I also agree that if the system is not accurate in real time then what data are you feeding it every morning, noon and night and why is the data over my own location so accurate when they use the very same systems to show our current weather. In fact they enhance the system using GPS and the local overland radar is fed into the data as well. I don't understand this explanation that they are cutting the funding....
    Is windy.com using real data or not and what is the discrepancy between the real time data and current data from the ground sources. Why would the system be so accurate overland but very "Smoothed" over the water?
    Why is there a 100 mph difference between the current data shown on your system and the reported data from the media..
    They are saying this storm is 185 mph sustained wind with 225 gusts, yet your data is 100 mhp slower.



  • @Siff I get what you're saying, but you can't really compare this to the general media. Modern entertainment journalism just makes stuff up. They don't care. Their information comes from the aether. They just want you to keep watching through the commercials to the next segment. They'd say the winds are made of explosive gas and are gusting at Mach 2.5 if it was believable.



  • @Mekronid Yes, you figured it out. Now can we get back to storm modeling? thanks



  • Please at least post a notice of wind info not being related to actual real time experience. I used this to track storm as my daughter and crewof S/Y Ocean Star are stranded in Tortola. I was am so confused and it absolutely added to all the stress!!! Did not know what info to trust.
    Finally realized the tracking portion is the only real time data that is helpful . All that other effort to post data is USELESS if it is not actual experience in real time.



  • @Mekronid is this actually happening? Are you blaming politics? Wow! I wouldn't be surprised if some of you guys say that Trump is responsible for the formation of Irma. Stop using Trump as argument to justify everything not done by own negligence. Politics are all the same, so they will always be your excuse to not to achieve anything then.


  • Moderator

    Please stop political discussion here, windy is about whether... Nothing else



  • Your wright



  • I am amazed at the accuracy of Windy hurricane 'forecasts'. OK the max wind speed is off, but you can tell the severity of the storm by its size and color bands. I kept some screen grabs captured last week using the european model and noticed Windy 'forecast' for Irma was spot on (going up west coast of Florida starting Sunday 10 Sept). I now am looking at forecast of Jose for Sept 18 ....wow a monster off the USA east coast and yet another hurricane forming at 20N 40W (while the GFS model does not show this at all). FABULOUS TOOL, CONGRATULATIONS!



  • @Siff The explanation makes perfect sense from a data science perspective. The grid is aggregating data...it is a window function. The simplest example is an average (rectangular window function). Take the average of 10, 10, 20, & 80. The average is 30. Clearly, 80 was included, but the output (30). When the OP says that it "smoothes" away extremal data, they literally mean smooth:
    https://en.wikipedia.org/wiki/Smoothing

    That said, there are better methods that can preserve extremal measurements. These are called "High Resolution Schemes" or "Total Variation Diminishing" methods:
    https://en.wikipedia.org/wiki/High-resolution_scheme
    https://en.wikipedia.org/wiki/Total_variation_denoising

    These let you recover data like this:
    0_1504971007927_Screen Shot 2017-09-09 at 11.28.54 AM.png

    The challenge with using these for weather is scale and computing power.

    Stay safe out there!



  • @Siff The sources that are providing the data sets for the likes of windy.com, has been proven to be selective in what data they distribute. For example the reporting of Earthquakes - Dutchsinse (A YouTuber who operates a channel warning various parts of the world of any imminent earthquake related threats) regularly demonstrates examples of earthquakes being reported on other nations websites, (other meaning non-US) but not by the USGS. This is a regular occurrence. Ergo if the source is unreliable why bother using its data?



  • @Ricky_Lightning See my post, this is not a "data withholding" problem. It's math. There are only so many ways to aggregate a bunch of measurements into one while preserving the character of the data.



  • @meteo-GR what would be the point in comparing the two as you've suggested? The source of the data in both examples, is from the same source.



  • Why are the rain and wind scales not high enough for purposes in hurricanes and unusual weather?



  • @Ottavs Because it is showing averages, not peak measurements.



  • My wind scale only goes up to 60 Kt.



  • @Ottavs Right. It's showing averages. You could have 3 measurements for a city, for example, 50mph, 50mph, and a gust of 150mph. The average is 83mph.



  • Rain scale only goes up to 1.2 in.



  • I think Irma is averaging more than any one component of 60. Sustained winds were reported at 175+. The wind scale offers colors for only up to 60.



  • @Ottavs It's only measuring how much is dropping for that hour, it's not adding up all the rain over time to a single area. 1.2 inches of rain in an hour is a lot.



  • @Ottavs First of all, it's in knots, not mph. Second, sustained wind measurements are much more complicated:
    https://en.wikipedia.org/wiki/Maximum_sustained_wind

    Basically, it's a 1 minute measurement. That's it. Windy is showing you the average wind speed for an hour. They could show you only the max wind speeds everywhere for the hour, but it would likely be very misleading.


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