It wasn’t predicted to be part of July’s skywatching highlights , but the northern lights may be visible overnight from a few northern states along the U.S.-Canadian border on Wednesday, July 1 through Friday, July 3. An Earth-directed, full halo coronal mass ejection — a cloud of charged particles — left the sun late on June 30 in the wake of an X-class solar flare, with different models forecasting its arrival either early or late on July 2, according to SpaceWeather.com . It could cause up to a G2 or even G3-class geomagnetic storm, which could mean aurora being seen on the northern horizon from U.S. states close to the border with Canada — most likely across parts of Montana, North Dakota, Minnesota and northern Wisconsin — but potentially much farther south in northern and lower Midwest states.

Long daylight hours in the wake of last week’s solstice , coupled with the light of the waning Strawberry Moon in the south after midnight, may make aurora harder to see.

Northern Lights Tonight: What To Expect

A G2-rated geomagnetic storm is not a major aurora outbreak forecast, but KP 4 or KP5 conditions can sometimes bring visible northern lights to the far northern tier of the U.S., especially near the Canadian border.

If the skies are clear, aurora watchers should look north, avoid bright lights, and use long-exposure settings on their phones or cameras. Cameras often detect faint aurora before the human eye can see color clearly.

The nine states with the best chance include the northern parts of Washington, Idaho, Montana, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan and Maine. It’s also possible that aurora will be glimpsed from Oregon, Wyoming, Nebraska, Iowa, Illinois, Indiana, Ohio, New York, Vermont and New Hampshire. If a G3 storm occurs, the aurora could potentially be seen in the northern parts of states farther south.

Aurora Alert: Incoming CME

A CME is a cloud of charged particles often created by solar flares. Unlike solar flares, which travel at light speed, CMEs move at up to 1,900 miles (3,000 kilometers) per second and take a few days to travel across the solar system. If they are Earth-directed, they can produce geomagnetic storms and auroras. A "halo CME" is when two CMEs arrive in succession to cause a strong geomagnetic storm.

According to a forecast by space weather experts at the National Oceanic and Atmospheric Administration, “Analysis is ongoing to evaluate potential Earth impacts from the 30 June X1.1 CME, with preliminary tracking suggesting an arrival over 03-04 Jul.”

A UK Met Office forecast slightly downplays the possibility of strong solar storms. “Geomagnetic activity is expected to be Unsettled to Active at first due to ongoing effects from the 26 Jun CME arrival, with G1 Minor Storms intervals probable, and a lower risk of G2 Moderate storming,” states the UK Met Office’s Space Weather forecast . “A possible further CME arrival later on Day 1 (01 Jul) could see these effects enhanced and continue into Day 2 (02 Jul), although this is lower confidence.”

Space weather can change rapidly, with forecasts revised frequently.

Northern Lights Alert: Latest Updates

To check visibility in real time, use NOAA’s 30-minute aurora forecast or download apps such as Aurora Now, My Aurora Forecast or Glendale Aurora for up-to-the-minute alerts and live solar wind data.

Whether an aurora display materializes largely depends on the interplanetary magnetic field, specifically its Bz component (you’ll find it in some of the above apps and on SpaceWeatherLive.com). Bz determines how easily solar energy enters Earth’s magnetosphere. When Bz points north, Earth’s field resists it; when Bz swings south, the two fields connect, allowing plasma to stream in. A sustained southward Bz of −5 nT or stronger usually signals an imminent display of aurora.

What Causes The Northern Lights

The northern lights are caused by the solar wind, a constant stream of charged particles flowing from the sun that interacts with Earth’s magnetic field. While most are deflected, some particles spiral along magnetic field lines toward the poles, colliding with oxygen and nitrogen atoms high in the atmosphere. These collisions excite the gases, causing them to release energy as shimmering light.

Wishing you clear skies and wide eyes.