WASHINGTON, Jumada I 26, 1436, Mar 17, 2015, SPA -- U.S. forecasters said Tuesday that a strong solar storm is hitting Earth with a surprisingly big geomagnetic jolt. According to forecasters, the storm could potentially affect power grids and GPS tracking while pushing the northern lights farther south. No damage has been reported so far. Thomas Berger, director of the Space Weather Prediction Center in Boulder, Colorado, said that two blasts of magnetic plasma left the sun Sunday, combined and arrived on Earth Tuesday much earlier and stronger than expected. The storm ranks a 4 on the National Oceanic and Atmospheric Administration’s (NOAA) 1 to 5 scale for geomagnetic effects. The storm can disrupt power grids only temporarily. Forecasters said auroras already were seen in the northern tier of the United States and Tuesday night may be seen as far south as the middle of the United States. --SPA 21:27 LOCAL TIME 18:27 GMT www.spa.gov.sa/w