(CAPE CANAVERAL, Fla.) — An unusually strong solar storm headed toward Earth could produce northern lights in the U.S. this weekend and potentially disrupt power and communications. The National Oceanic and Atmospheric Administration issued a rare geomagnetic storm watch — the first in nearly 20 years. That was expected to become a warning Friday night, when the effects of the solar outburst were due to reach Earth. [time-brightcove not-tgx=”true”] NOAA already has alerted operators of power plants and spacecraft in orbit to take precautions. “As far as the worst situation expected here at Earth, that’s tough to say and I wouldn’t want to speculate on that,” said NOAA space weather forecaster Shawn Dahl.