Welcome to Koh Samia’s weather page! (Beta)
Reasons behind this tool
During my intent of qualification for the 2010 Singlehanded Transpac, I found myself without real wind forecasts just left of San Clemente Island. I just couldn’t find anything to check the the weather at ’200 miles offshore’ distance needed for my qualification sail. So, after not being able to qualify due to boat problems, I decided to create a tool that would allow me to ‘see’ what the wind was supposed to do ‘out there’.
And this is it!! The most fun I’ve had in front of a keyboard since… since long time ago. And I want to thank the engineers at Google for creating a platform that is so much fun to work with. Thank you guys!!!
How this works
- All wind data is obtained by downloading GRIB forecast files generated by NOAA.
- All dates and times are in Greenwich Mean Time (GMT).
- Arrows represent wind speed and direction.
- The arrow goes with the wind, and the feathers specify the wind speed. No feathers means less than 3 knots of wind, a small feather averages 5 knots, a long one 10 and a triangle 50 knots. Adding the feather values on each arrow you’ll get the wind speed. It seems complex, but you’ll get used to it soon… or at least I hope so.
- There are two different forecasts: “GFS” provides worldwide data and longer predictions times, it may not have enough resolution for short offshore distances but it’s great for long distances. The map will switch automatically between three different sets of data provided by NOAA depending on your zoom level, and I think that’s kind of cool. “NAM” is the highest resolution data I’ve found, but provides forecasts for North America only (including some of the North-East Pacific Ocean and part of the Caribbean). It also provides an hourly prediction compared to the 3/6-hour interval of GFS.
OK, now the disclaimers
- The whole system is ‘auto-magick’. Meaning I do not verify any data… nor anybody else does. Data is pulled from NOAA’s servers every six hours, processed without any human intervention and served to you in a silver-map-tray. No spices nor sauces.
- I will, though, check the website periodically and ensure the server is doing what is supposed to do and data is being processed correctly. In fact, I’ll be using the information to plan for my personal sailing trips…
- “GFS” forecasts at the lowest zoom levels are in a 6 hour interval, but at higher zooms are at 3 hour interval. Instead of showing everything every 6 hours (and very few people would have noticed), I’ve decided to provide all the information available, so, when at continent level zoom, when looking at a time that is not multiple of 6 I’ll be showing the previous forecast. Meaning that at 3, 9, 15 and 21h I’ll be showing the forecast at 0, 6, 12 and 18h respectively. Hope this is not too confusing.
- It may/does not work when using Microsoft Explorer. I do not own (nor I plan to) a computer with Windows, so I can not ensure it works there. We’ve tried, though, with Firefox and Chrome in Windows using a friend’s computer, and it works just fine… so if you want to play with it you may want to switch. Sorry for this.
- The whole thing runs on a server that is definitely not designed for serving this kind of real time data. Sometimes you may find some delays on the refresh… it happens to me too. I will be monitoring the load, and, if there is really interest out there on the tool, I’ll upgrade to a real server. But I’ll not do it if I’m the only one using it… I rather put the money on the boat.
- I’ve done my best to ensure accuracy of the data shown, but I’m not perfect, so this should be used for informational purposes only, and I accept no responsibility of decisions taken based on the data shown here. Use at your own risk.
- Please, enjoy and come back as many times as you want, and if you find issues and/or have suggestions, please let me know.
- Also, there are a significant amount of sleepless nights and weekends under all this, so, please, be cool…