Geomagnetic storms bring possible northern lights

Severe solar storms and sun flares buffeting Earth this weekend could bring the northern lights to Colorado, space weather forecasters said Friday.

The National Oceanic and Atmospheric Administration issued a severe, G4 geomagnetic storm watch — the second highest on the scale — for the first time since since January 2005 on Thursday, weather officials said.

At least five coronal mass ejections (CMEs) — pulses of plasma and magnetic fields from the sun — are headed to Earth this weekend, space weather officials said. The waves of solar energy could arrive as early as mid-day Friday or as late as Sunday.

The fastest CMEs can reach Earth from the Sun in 15 to 18 hours, and slower CMEs can take several days to arrive, the National Oceanic and Atmospheric Administration said.

When CME’s hit the earth, they create geomagnetic storms that threaten power grids and voltage control, disrupt satellite services and low-frequency radio navigation systems and cause issues for spacecraft operations, weather officials said.

Space weather officials said they spotted several strong sun flares associated with a large, magnetically complex sunspot cluster more than 16 times the diameter of Earth. The cluster signals more solar activity to come.

G4 storms are rare, weather officials said. When abnormally strong geomagnetic storms occur, bright northern lights will be visible at unusually low latitudes.

According to NASA, CMEs create currents in Earth’s magnetic fields that send particles to the North and South Poles. When those particles interact with oxygen and nitrogen, they can create auroras.

The aurora borealis has been seen as low as Alabama and northern California during severe, G4 storms in the past.

NOAA’s space weather prediction center released maps showing the northern lights’ projected reach Friday and Saturday, with northern Colorado making the cut both nights for at least weak visibility.

Coloradans who want a better chance at seeing the aurora will need to drive to the Wyoming border, which is firmly in the “green zone” for tonight’s light show. The drive from Denver usually takes less than two hours.

The lights are best viewed away from the city, in areas where minimal light pollution creates the darkest possible conditions.

However, continued rain showers and thunderstorms forecasted throughout Colorado’s Front Range — and snow storms projected for the mountains — could mean the skies will be too cloudy to see the lights, National Weather Service meteorologists said.

A northern lights forecast was not yet available for Sunday night.