A severe geomagnetic storm could cause colorful auroras over Northern California and Alabama CNNNorthern Lights Forecast Upgraded To ‘Severe’ For Half Of The U.S. — When To See Aurora This Week Forbes‘Severe’ geomagnetic storm to slam Earth Thursday, with auroras possible as far south as California and Alabama Livescience.comThe sun fires off another powerful X flare, triggering radio blackouts across the Americas (video) Space.comU.S. Issues Solar Storm Watch After Large Outburst From the Sun The New York Times