She said: "From midnight there will be widespread cloud so there is unlikely to be much visibility."
Forecasters at the U.S. government's Space Weather Prediction Center said the storm is growing in intensity as it speeds outward from the sun. The charged particles hit Earth at 4 million mph (6.4 million kph).
Nasa solar physicist Alex Young said: "It could give us a bit of a jolt."
The solar storm is likely to last until Friday morning, although further eruptions may follow.
In North America, auroras or Northern Lights could stretch as far south as the Great Lakes states or even lower, but a full moon will make them hard to see, said Joe Kunches, a scientist for the National Oceanic and Atmospheric Administration.
Solar storms have three ways they can disrupt technology on Earth: with magnetic, radio and radiation emissions. This is an unusual situation when all three types of emissions are likely to be strong, said Kunches.
In 1989, a strong solar storm knocked out the power grid in Quebec, Canada, leaving 6 million people without power.
Harlan Spence, an astrophysicist at the University of New Hampshire who is principal investigator on the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) aboard NASA's Lunar Reconnaissance Orbiter, said the sun was on the ascendant phase of its 11-year cycle of solar activity, with the peak expected next year.
"It's a clear harbinger that the Sun is waking up," Spence told Reuters.
Intellpuke: You can read this article by Guardian news editor and reporter David Batty, with reporting by various news agencies, in context here: www.guardian.co.uk/science/2012/mar/07/massive-solar-storm-heading-earth