Okay, this sounds really cool. It's a solar tsunami. And, yes, it's a little geeky, but the bottom line is that there should be celestial show tonight over the nothern U.S. and Canada. From NASA:
On August 1st around 0855 UT, Earth orbiting satellites detected a C3-class solar flare. The origin of the blast was Earth-facing sunspot 1092. C-class solar flares are small (when compared to X and M-class flares) and usually have few noticeable consequences here on Earth besides aurorae. This one has spawned a coronal mass ejection heading in Earth's direction.This is what a CME looks like:
Coronal mass ejections (or CMEs) are large clouds of charged particles that are ejected from the Sun over the course of several hours and can carry up to ten billion tons (1016 grams) of plasma. They expand away from the Sun at speeds as high as a million miles an hour. A CME can make the 93-million-mile journey to Earth in just three to four days.
When a coronal mass ejection reaches Earth, it interacts with our planet’s magnetic field, potentially creating a geomagnetic storm. Solar particles stream down the field lines toward Earth’s poles and collide with atoms of nitrogen and oxygen in the atmosphere, resulting in spectacular auroral displays. On the evening of August 3rd/4th, skywatchers in the northern U.S. and other countries should look toward the north for the rippling dancing “curtains” of green and red light.
More from the Winnipeg Free Press:
Those events happen fairly often on the sun, but it's rarer for them to be directed at the Earth, said astrophysicist Leon Golub. The light show could be visible around 2 a.m. Wednesday and last 24 hours — but the emphasis should be on the word "could," he said.
Golub, speaking from Cambridge, Mass., said viewing chances in the U.S. are probably limited to the northern states. But Welch said in Canada it may be possible to see them "any place where it's dark."
People in big cities likely won't be able to see anything, and still the best locations for viewing the northern lights will be farther north, Golub said. But it's not every day that southern Canadians can see the lights.