WRAL WeatherCenter Blog

Solar flare could make aurora visible across the northern U.S.

Posted October 11, 2021 6:37 p.m. EDT
Updated October 12, 2021 9:07 a.m. EDT

Expedition 52 Flight Engineer Jack Fischer of NASA shared photos and time-lapse video of a glowing green aurora seen from his vantage point 250 miles up, aboard the International Space Station. This aurora photo was taken on June 26, 2017.

NOAA’s Space Weather Prediction Center issued a G2 moderate geomagnetic storm watch Sunday in anticipation of the arrival of a solar flare. This has also stirred up excitement as far south as the Washington, D.C., area for a rare glimpse of the northern lights or aurora.

Coronal Mass Ejection (CME) from the Sun as seen by NASA/SDO mission on October 9, 2021

Most of the energy and the charged particles that comes with a coronal mass ejection (CME) like the one that erupted on Friday are deflected away by Earth's magnetic field. But some are captured and follow magnetic field lines toward the north and south poles.

All that energy essentially slams into molecules in our atmosphere, heating them up and producing colors. The wavy patterns, often described as curtains of light, are those magnetic field lines on display.

Forecasters have a little time to analyze the CME and its path and speed over the 1-3 days it takes to reach Earth.

Bursts of energy from the Sun create aurora

The stronger the geomagnetic storm, the deeper into the magnetic field that energy makes it way in, the further south aurora might be seen.

Researchers at the Geophysical Institute at the University of Alaska, Fairbanks are forecasting visible high aurora activity visible as far south as the upper Midwest and Great Lakes regions with visibility possible low on the horizon (above the solid green in the map below) as far south as a line stretching from Salem, Oregon to the Washington D.C. area.

Aurora forecast for 2021-10-11

A G3 strong geomagnetic storm watch last December created even more excitement with that forecasted visibility line reaching into North Carolina. While forecasters don't expect the show to extend that far south tonight, G3 or G4 class storms are more likely to reach the Carolinas, but aurora are hard to predict.

If you find yourself out this evening look north for a faint green cast to the sky.

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