Sunspots, often the precursors to gigantic solar flares that can potentially destroy our entire planet in an instant (well, nearly), can now be accurately predicted two days ahead of when they emerge on the sun's surface. So relax, you'll have plenty of time to put on your tinfoil hat and prepare for the apocalypse.
The key to predicting sunspots and solar flares is being able to detect what's going on inside the sun, which (if you hadn't noticed) is a huge ball of exploding plasma, so digging a hole and dropping a sensor down into it is probably not an option.
What we can do instead, as researchers at Stanford have just discovered, is to use seismic waves travelling through the sun to provide clues to what's going on under the surface. We do the same thing here on Earth: seismic (or sound) waves travel at different speeds through different materials, and we can use them to figure out the structure of our planet to a greater depth than we can possibly drill to. On the sun, these seismic waves speed up significantly when they encounter a sunspot rising to the surface, and by using multiple measurements, scientists have been able to accurately estimate when and where a sunspot will appear a day or two before it actually does.
Being able to make predictions like this is a big deal for anyone and anything in space, since it gives astronauts and satellites a chance to batten down the hatches in the event that something bad is pointed toward Earth orbit. For the rest of us, space weather is usually not a factor in our daily lives, but if something big and nasty does happen, this system has the potential to give us all a little extra warning.