AURORA ALERT: a strong solar storm could bring the northern lights to much of the U.S. tonight (Thursday, June 4). NOAA has issued a G3 ("strong") geomagnetic storm watch for June 4 into June 5. 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: an active sunspot region called AR 4455 fired off several CMEs (giant clouds of solar plasma) on June 3, including ones tied to an M9.5, M7.8, and an X1 flare. At least three are aimed our way and may arrive together. NOAA expects the first impact around midday Thursday (18 UT or about 2 PM Eastern, 1 PM Central, 11 AM Pacific), while NASA's model leans to the evening and another (HUXt) pushes it into the early hours of June 5. It's a wide window, so watch tonight into early Friday.
How strong: NOAA's official forecast is G3 (Kp 7), but a lot depends on whether we take a direct hit or a glancing blow, so it could land higher or lower. Don't put too much stock in pinpoint Kp numbers or app forecasts days out. Space weather is hard to predict and the storm will evolve on its own. Treat them 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. Two things working against us: clouds (even thin, high clouds can mute the show) and a bright ~80%-lit moon that rises around local midnight. Your best window is the dark gap after dusk and before the moon comes up.
The map shows roughly how far south the aurora might reach tonight. Forecasts like this don't always come true, so keep your hopes up but your expectations realistic.
A few free resources to help you chase:
Sign up for my aurora alerts + guides: https://t.co/TmXQ9bcWkT
Live aurora webcams (100+): https://t.co/6p6lf2217i
What is a substorm? https://t.co/4zGp9vcHYG
What resources you may look at but are actually NOT helpful for chasing in real-time: https://t.co/dXajNLSH25
How to read the HUXt model: https://t.co/gWx1zGXjeB
Support these free alerts on Patreon: https://t.co/8f4dgCQHIs