Update January 2014: New overlays with temperature, pressure, cloud, and rain were added!
I just saw an amazing tweet by Pakistani string theorist Amer Iqbal (whom I know from Harvard) and you have to see it:
Real-time global wind map (earth.nullschool.net)It's beautiful, fast, and hopefully accurate.
Using the usual gestures (dragging with the left mouse button, mouse wheel etc.), you may rotate the globe, zoom it in/out, and/or focus on the region you are interested in. The wind flows are visualized by animated flying green jets, sort of.
It may take a few seconds for the wind data to load and for the green animation to begin.
When I was posting this blog post for the first time, I still hadn't verified the credibility of the data and who is behind the impressive project.
Update: I have compared the graphical wind data with Weather Underground and the degree of agreement leads me to believe that the data are legit.
The information about the application and the source of its data may be accessed by clicking at the "earth" label in the lower left corner. The author (Cameron Beccario, software engineer focusing on .NET in Japan) seems to be a citizen scientist if we use this term and the data are from NCEP / US National Weather Service / NOAA.
The "earth" button also offers some options – changing the height (parameterized by pressure: e.g. the high-altitude 10 hPa pressure winds are more uniform, stronger, and red, purple, or even white if too strong), projection of the terrestrial sphere, changing the reference time (yesterday, forecast for tomorrow), UTC vs local time, visualizing your current location (permission may be needed; a "cross" closes the local info), and more. Left-clicking a place (with no dragging) gives you some local information about the place. If you click at "earth" again, the menus disappear.
The author kindly told me that he applies a simple bilinear interpolation to fill the gaps in the NCEP data – it surely looks good to me. He is unusually modest which is the reason why you probably haven't heard about the widget earlier.
Just by looking at the animations, one can learn some things. For example, the winds over oceans are generally much stronger than those over the land, indeed. The vortices simply love to appear at various spots. It would be interesting to see how much the wind field follows from the pressure field (a potential: the vortices imply non-potentiality), and other things.