How Does Your Phone Know It's Going to Rain Tomorrow?
The woman on your phone screen tells you it might rain tomorrow afternoon, so you throw an umbrella into your bag before heading out. The next day, the clouds roll in around 2 PM — right on cue. You glance up, a little impressed, a little unsettled. How did she know? How does anyone know what the sky will do a full day from now? The short answer is: math, balloons, satellites, and an idea that seems almost too simple to work — that if you measure the atmosphere everywhere at once, you can calculate where it will be tomorrow. The long answer is where the magic really lives. ...