WISCONSIN

Northern lights might - the operative word is might - be visible in Wisconsin skies tonight

Meg Jones
Milwaukee Journal Sentinel

Not saying it will happen, but scientists are predicting this evening could be a good night in Wisconsin to see the pulsing, lava lamp-esque phenomena in the sky known as the northern lights.

The Space Weather Prediction Center issued a geomagnetic storm watch for Tuesday that shows Wisconsin smack dab in the center of the most likely area for the aurora borealis, the fancy name for northern lights.

If the lights deign to show up, the good news is that night skies throughout most of Wisconsin will be clear tonight, though some parts of northwestern Wisconsin could get high clouds, said Marcia Cronce, a National Weather Service meteorologist based in Sullivan.

Northern lights are seen in a 30-second exposure taken at Elsworth Park in Bayside on Oct. 24, 2011.

What sometimes looks like a neon blanket thrown against the night sky is actually electrically charged particles from the sun colliding with gaseous particles entering the Earth's atmosphere. While green and pink are the most common colors, the northern lights can feature quite a few more hues including red, yellow, blue and violet.

The lights can also be seen in the southern hemisphere where they're called aurora australis.

The most common is a pale yellowish-green which is produced by oxygen molecules located about 60 miles above Earth, according to the Northern Lights Centre in Canada. Rare, all-red auroras are produced by high-altitude oxygen, at heights of up to 200 miles, while blue or purplish-red auroras are the product of nitrogen.

"It depends on whether the particles of the sun hit oxygen or nitrogen," said Jean Creighton, director of the University of Wisconsin-Milwaukee's Manfred Olson Planetarium. "Oxygen only makes two colors - yellowish-green or red if it hits the upper atmosphere. Nitrogen makes a whole pile of colors."

Creighton has seen northern lights several times but the most memorable for her was four years ago when she was chosen to fly in the astronomical observatory SOFIA and saw them above northern Canada.

"They're beautiful. They have an otherworldliness to them," said Creighton.

Bob Bonadurer, director of the Milwaukee Public Museum's Daniel M. Soref National Geographic Dome Theater & Planetarium, isn't sure whether tonight will be a good night for the aurora borealis because the solar storm is subsiding.

And the lights are less likely to be seen in southern Wisconsin compared to the northern third.

"We're a northern state, but Milwaukee is closer to the equator than the north pole. The reason that's important is these particles are deflected by the magnetic field and spiral in at the magnetic poles," said Bonadurer. "The further north you are the better you can see them."

The northern lights can be best seen in dark skies, meaning away from light pollution. Anyone wanting to hang out in their backyards or parks tonight can expect comfortable temperatures in the 60s throughout the state.

And if the northern lights don't make an appearance, it's a great evening to glimpse Venus low in the horizon, Jupiter and a sliver of the moon.

A sky chart showing the position of Venus, Jupiter and a sliver of the moon from the skies over Milwaukee this week.