NOAA forecasters say there is a 65% chance of minor G1-class geomagnetic storms on November 21st, when a high-speed stream of solar wind is expected to hit Earth's magnetic field. The gaseous material is flowing from a large hole in the sun's atmosphere. "Coronal Holes," are vast regions in the sun's atmosphere where magnetic fields open up and allow solar wind to escape. They look dark in ultraviolet images because the hot glowing plasma normally contained there is missing. In this case, the plasma is making a beeline for Earth. High-latitude sky watchers should be alert for auroras on November 21st when the solar wind arrives. G1-class storms can produce Northern Lights as far south as US states ranging from Maine to Washington.