The world has warned that the strongest solar storm in 20 years will hit on Friday

Authorities in America have issued the first Severe Geomagnetic Storm Watch (G4) alert in almost 20 years, as a powerful solar storm will hit Earth on Friday. The National Oceanic and Atmospheric Administration (NOAA) issued the alert late Thursday, the first alert of this level since 2005.

In January 2005, Earth was hit with the highest level of solar radiation in 50 years. Today’s storm could be strong enough to disrupt power grids, GPS satellites and some communications.

The electromagnetic storm will collide with Earth’s atmosphere after solar storms on the Sun’s surface earlier this week. They could bring spectacular displays of the aurora borealis and possible disruption of everything from GPS to the internet.

The alert says: “NOAA’s Space Weather Prediction Center (SWPC) – a division of the National Weather Service – is monitoring the sun following a series of solar flares and coronal mass ejections that began on May 8. G4) Geomagnetic storm watch for Friday evening.

“Additional solar flares could cause geomagnetic storm conditions to persist through the weekend. A large sunspot cluster has produced several moderate to strong solar flares since 5:00 a.m. ET Wednesday. At least five flares have been associated with coronal mass ejections that appear to be Earth-directed SWPC meteorologists will monitor NOAA and NASA space assets for the onset of a geomagnetic storm.”

Coronal mass ejections are bursts of plasma and magnetic fields from the sun’s surface.

The warning added: “Geomagnetic storms can impact infrastructure in near-Earth orbit and on the Earth’s surface” and said they could “potentially disrupt communications, power grid, navigation, radio and satellite operations”.

A severe thunderstorm watch will be in effect until Sunday evening. The alert says: “SWPC has notified the operators of these systems so they can take protective measures,” officials wrote in administering the action. Geomagnetic storms can also trigger spectacular aurora displays on Earth.

People in the UK could see the Northern Lights this weekend.