A massive solar eruption has triggered an emergency warning for a geomagnetic storm that could briefly affect power grids, satellites and communications across the northern US.

The alert, issued early Wednesday by NOAA's Space Weather Prediction Center, forecasts moderate to potentially strong geomagnetic activity through Thursday.

Such storms are caused by charged particles from the sun interacting with Earth's magnetic field, which can force extra electricity through power lines and pipelines, sometimes causing brief voltage fluctuations.

The storm stems from a powerful solar flare on November 30, which sent a coronal mass ejection (CME) hurtling toward Earth at nearly 1.4 million miles per hour. 

The Space Weather Prediction Center (SWPC) reported that the strongest currents are expected in the Upper Midwest, around the Great Lakes and into the Northeast. 

When a geomagnetic storm pushes electric currents into the ground, it acts like an invisible 'battery,' forcing extra electricity through power lines, pipelines, and even railroad tracks. 

The aurora is expected to light up the night sky across northern states, including Washington, Idaho, Montana, Wyoming, both Dakotas, Minnesota, Wisconsin, Michigan, and even parts of New York, Vermont, New Hampshire, and Maine. Most of Alaska is also forecast to fall within the aurora zone. 

Sky watchers may see the northern lights as far south as northern Iowa.

To catch the best views of the northern lights, NOAA suggested heading north, closer to the Earth's magnetic pole and finding an open location with an unobstructed view of the northern sky. 

The aurora is typically most active between 10pm and 2am, so timing your outing during those hours increases the chances of seeing the lights. 

NASA reported on the solar flare, noting it was classified as an X1.9 flare, which is the most intense level.

The CME is now heading toward Earth and is expected to deliver 'a glancing blow,' triggering a G2, or moderate, level watch.

G1 to G2 storms can cause weak power grid fluctuations, minor satellite impacts, and temporary high-frequency radio interruptions.

Officials said the storm is expected to produce 'mainly manageable effects' on technology. 

Satellite systems, mobile networks, GPS signals, and radio communications could experience brief disruptions, though serious technical problems are uncommon at this level.

On Tuesday, parts of Australia and Southeast Asia reported short-lived interruptions in radio communications.

If the CME is delayed today, officials noted that a G2 storm could occur on Thursday. 

There are no warnings yet for December 5. 

The timing of the storm coincides with a series of high-energy events on the sun that began late last month, including multiple X-class and M-class solar flares. 

NOAA warned that additional solar flare activity could occur in the coming days, following the appearance of a large cluster of sunspots in the sun’s southeast quadrant. 

Sunspots are temporary, dark, and cooler regions on the sun's surface caused by intense magnetic activity 

The largest and potentially most active of these sunspots has been designated 4294. 

These eruptions have generated radio bursts and Type II emissions, both indicators of fast-moving CMEs capable of triggering geomagnetic storms on Earth.