The dazzling, multicolored northern lights, visible in all but 9 of the Lower 48 states Sunday night and arguably the most impressive here in 13 years, may not be the last of this cycle. While hardly a certainty, a new aurora can’t be ruled out over at least parts of the country Tuesday night. The auroral ovals, the swaths of the atmosphere circling the planet’s highest latitudes beneath which auroras are visible, are normally found much farther north—in Canada and Alaska—or south near Antarctica.
NOAA space weather forecaster Michael Weaver says a geomagnetic storm as intense as the one behind Sunday night’s aurora occurs on average only 4 times each 11-year solar cycle. While an “M-class” solar flare set off Sunday night’s celestial display, a second, more powerful “X-class” flare Sunday afternoon could mean Earth’s upper atmosphere may again be showered by charged particles and that auroral displays might reappear Tuesday night, says Triton College astronomer Dan Joyce.
Geomagnetic storms occur as energy off solar flares excite particles in earth's upper atmosphere into giving off light. High frequency radio transmissions and even electricity transmission can be disrupted during such storms.
— Tom Skilling
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
