Strong geomagnetic storm — aurora possible tonight
Forecast Kp 6 (G2) · possibly visible across the northern-tier states and southern Canada
NOAA space-weather forecasters expect a geomagnetic storm reaching Kp 6 (G2) within the next 24 hours. At that level the aurora can be visible across the northern-tier states and southern Canada — roughly down to 50°N latitude. Get away from city lights, look north after dark, and give your eyes 20 minutes to adjust. A phone camera on night mode will often pick up color your eyes can't.
What causes the aurora?
The Sun continuously streams charged particles past Earth. When a solar eruption — a coronal mass ejection — slams into Earth’s magnetic field, that field funnels particles down toward the magnetic poles, where they strike oxygen and nitrogen 100–300 km up and make the air itself glow: green and red from oxygen, blue and purple from nitrogen.
Will I see it from here?
It depends on the storm’s strength, measured by the Kp index (0–9). Kp 5 reaches the northern-tier US states and central Europe; Kp 7–8 can push visible aurora to the latitude of the central US and southern Europe. Look north, after dark, away from city lights — and know that cameras see aurora before eyes do: a 3-second phone exposure will show color in a sky that looks faintly milky to the naked eye.
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