AURORA ALERT: a strong solar storm could bring the northern lights to much of the U.S. tomorrow night (Sunday, June 7). NOAA has issued a G3 ("strong") geomagnetic storm watch for June 8. If it pans out, the aurora may be visible across the northern states and into the central U.S., with a small chance even farther south during brief bursts called substorms.
What's happening: on June 6, a large filament erupted from sunspot region AR 4461 alongside an M1.8 solar flare. The flare was modest, but the eruption launched a fast, full-halo CME (a giant cloud of solar plasma) with a clear Earth-directed component, modeled at over 1,000 km/s. NOAA's model has it arriving around 11 UT on June 8 (7 AM Eastern, 6 AM Central, 4 AM Pacific on Monday morning), while NASA's runs lean earlier, closer to Sunday evening for North America.
All models carry about /- 7 hours of uncertainty, so the realistic window runs from Sunday evening through Monday midday. For U.S. chasers, that makes Sunday night into early Monday the night to watch. If the CME shows up late, Monday night becomes the backup, and NOAA already has a G2 watch posted for June 9.
How strong: NOAA's official forecast is G3 (Kp 7), but the bulk of this CME is heading south and east of the Sun-Earth line, so a lot depends on whether we catch the core or a flank. It could land higher or lower. Don't put too much stock in pinpoint Kp numbers or app forecasts before the storm arrives. Space weather is hard to predict and the storm will evolve on its own. Treat forecasts as a sign activity may be enhanced, not a guarantee.
How to catch it: get away from city lights, find a clear view to the north, and look during the darkest part of the night. Watch for substorms, when the sky can go from dark to full of color in just a few minutes. Unlike last week's storm, the moon is on our side this time: it's half-lit and doesn't rise until roughly 1-2 AM local, so the evening and midnight hours are properly dark. Clouds are the bigger wildcard, so check your local forecast before you drive anywhere.
The map shows roughly how far south the aurora might reach Sunday night. Forecasts like this don't always come true, so keep your hopes up but your expectations realistic.
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