(EARTHQUAKE WATCH ETC.) The sun has unleashed three separate solar storms which have combined to smash into Earth's atmosphere.

Forecasters say the storm will continue overnight, causing huge aurora to be visible and even potentially causing problems with electricity supplies on Earth.

It could cause strong auroras as far south as the Canadian border with the U.S. 

Scroll down for video 

'The geomagnetic storm began as forecasted and quickly ramped up to severe (G4) levels,' the Government's Space Weather Prediction service said.

It issued the G4 Alert at 1858 UT (2:58 pm EDT), after the storm slammed into Earth at 1839 UT (2:39 pm EDT).

This is the same intensity level reached in March, 2015 during the St. Patrick's Day storm, which supercharged auroras for skywatchers in northern parts of the United States.

'The geomagnetic storm began as forecasted and quickly ramped up to severe (G4) levels,' the Government's Space Weather Prediction service said.

It issued the G4 Alert at 1858 UT (2:58 pm EDT), after the storm slammed into Earth at 1839 UT (2:39 pm EDT).

This is the same intensity level reached in March, 2015 during the St. Patrick's Day storm, which supercharged auroras for skywatchers in northern parts of the United States.

'This is the very early stages of an event that will play out over many hours, with SWPC forecasting continuing storm level intensities into tomorrow. 

'In Europe watchers should be looking for the aurora now and there is hope for those over the US tonight.'

The geomagnetic storm could cause strong auroras as far south as the Canadian border with the U.S., but it's possible that the beautiful phenomenon will be visible well south of there. 

The best viewing conditions will be away from city lights, with clear skies, looking toward the north, astronomers say. 

The storm could increase the drag on satellites in low-Earth orbit, possibly meaning that mission controllers will need to make course corrections, the SWCP said.

In addition, the surfaces of spacecraft could become charged, potentially affecting the operation of the craft. 

It could also cause issues with electrical grids on Earth and interfere with some types of aircraft radio transmissions. 

This solar storm is being caused by three coronal mass ejections — bursts of hot plasma shot from the sun — that met up in space today.

All three CMEs were shot out from the same region of the sun, a sunspot region called 12371. 

One ejection was flung into space on June 18, with another occurring a day later. 

The most recent CME erupted from the sun on June 21 and is moving more quickly than either of the other two Earth-directed bursts of plasma, a cosmic coincidence that has them all impacting Earth's magnetic field at about the same time.

The SWPC was originally predicting that, on Monday, the storm could reach G3 level — a 'strong' solar storm that could create brilliant auroras but also may interfere with satellites in space.

The SWPC has a 30-minute aurora forecast tool to help people more easily see when and where auroras are expected to become active.