Northern lights could return to the night sky above parts of up to 28 U.S. states, across Canada and in northern Europe this weekend, as three coronal mass ejections (CMEs) from the sun potentially reach Earth between Friday, Oct. 9 and Sunday, Oct. 11.

The National Oceanic and Atmospheric Administration (NOAA) has forecast a G2 (Moderate) geomagnetic storm, with the strongest activity now expected between 2 p.m. and 8 p.m. EDT on Friday, Oct. 9 — several hours later than previously predicted. That could bring the northern lights to parts of the northern U.S. around nightfall, particularly if storm conditions persist into the evening.

If the aurora reaches the northern U.S., a smartphone camera may capture faint colors that are difficult to see with the naked eye — most likely low on the northern horizon.

Northern Lights Forecast Tonight: G2 Geomagnetic Storm Expected

“G1-G2 (Minor-Moderate) geomagnetic storms are likely on 09 Oct due to the anticipated arrival of a CME from 06 Oct,” NOAA’s forecast states.

The UK Met Office forecasts G1, G2 and possibly even G3 storming over the weekend, the latter a potential Kp 7 event that could bring aurora farther south than usual. However, it notes “significant uncertainty in the timing of these features.”

With a new moon due on Saturday, Oct. 10, skies will also be virtually free of moonlight, creating excellent conditions for viewing and photographing the northern lights wherever skies are clear.

Northern Lights Forecast This Weekend: Three CMEs Could Hit Earth

The northern lights could remain active throughout the weekend as a series of solar eruptions heads toward Earth.

The current G2 geomagnetic storm forecast for Friday, Oct. 9, follows an M1.4-class solar flare on Tuesday, Oct. 6, which launched a full-halo coronal mass ejection. A CME is an eruption of solar material and magnetic fields from the sun that typically takes a few days to reach Earth. It’s called a “halo” CME because, in coronagraph images from the LASCO instrument aboard NASA’s SOHO spacecraft, the expanding cloud of solar material appears to surround the sun.

Further solar activity has since produced additional CMEs, potentially extending the northern lights opportunity through the weekend. According to the UK Met Office, a glancing blow from a CME launched on Wednesday, Oct. 7 could bring G1 (Minor) geomagnetic storms on Saturday, Oct. 10, with a slight chance of G2 (Moderate) conditions.

A third CME, associated with an M6.7-class solar flare on Thursday, Oct. 8, could arrive on Sunday, Oct. 11. The Met Office forecasts active to G1 conditions, with a chance of G2 and a slight chance of G3 (Strong) geomagnetic storms.

That means there could be three separate opportunities to see the northern lights between Friday and Sunday, although the precise timing and strength of each potential CME impact remain uncertain. Nothing is guaranteed because the exact strength of any geomagnetic storm depends on the speed, density and magnetic orientation of the incoming solar material when it reaches Earth.

Northern Lights Forecast For The U.S.: Up To 28 States

If G1 conditions develop, Alaska and states across the northern tier of the contiguous U.S. (Washington, Idaho, Montana, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, Maine, Vermont and New Hampshire) could have opportunities to see or photograph aurora, particularly from dark locations near the Canadian border.

Should geomagnetic activity strengthen to G2 levels, the auroral oval could expand farther south, potentially allowing photographers in states such as Oregon, Wyoming, Nebraska, Iowa, Illinois, Indiana, Ohio, Colorado, Pennsylvania and New York to capture faint displays.

At the less likely G3 level, auroras could become visible or photographable even farther south, potentially reaching parts of Kansas, Missouri, Kentucky, West Virginia, Virginia and Maryland, particularly from dark locations with unobstructed views north.

Aurora-chasing website Cosmik has live odds for all states and 552 cities in 10 languages, updated from NOAA’s data, so you can check whether your location may see aurora tonight.

Where And When To See The Northern Lights Tonight

A G1 forecast does not guarantee the northern lights will appear from any particular location, and apps such as Aurora Now, My Aurora Forecast or Glendale Aurora should be used for up-to-the-minute alerts and live solar wind data. Aurora visibility ultimately depends on solar wind strength, cloud cover, light pollution and the orientation of the interplanetary magnetic field.

The latter — measured as Bz — will matter once the CME reaches Earth. A sustained southward Bz can favor stronger coupling between the solar wind and Earth’s magnetic field, increasing the potential for auroral activity to be seen farther south than expected. If Bz remains northward, however, the resulting display may be weak or restricted to higher latitudes.

Wishing you clear skies and wide eyes.