WEEKEND CME STRIKES: Over the weekend, a pair of CMEs hit Earth--one on May 18th (0100 UT) and another on May 19th (2250 UT). The impacts, especially the first one, rattled Earth's magnetic field and sparked Northern Lights visible as far south as Colorado. Some of the brightest appeared over Cape Cod, Massachusetts, where photographer Chris Cook took this self-portrait:
More auroras are possible tonight as Earth's magnetic field continues to reverberate from the impacts. NOAA forecasters estimate a 75% chance of polar geomagnetic storms on May 20th.