The northern lights may be visible overnight from a few northern states along the U.S.-Canadian border on Monday, June 29, into Tuesday, June 30. A coronal mass ejection — a cloud of charged particles — left the sun late on June 26 in Earth’s direction, with NASA models forecasting its arrival on Earth. It could cause up to a G2-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.

Long daylight hours in the wake of last week’s solstice , coupled with the rising on Monday, June 29, of the full Strawberry Moon in the south, may make aurora harder to see.

Northern Lights Forecast: What To Expect

A G1 or G2-rated geomagnetic storm is not a major aurora outbreak forecast. However, 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. Here’s how to photograph the northern lights using a phone .

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.

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.

According to SpaceWeather.com , this CME could spark a G1-class geomagnetic storm when it reaches Earth. According to a forecast by space weather experts at the National Oceanic and Atmospheric Administration, “Enhanced conditions are expected to return early to mid on 30 Jun due to the CME that left the Sun late on 26 Jun.”

A UK Met Office forecast slightly ups the ante. “CME arrival on day 3 is expected to increase activity to Active to G1 Minor Storms with a chance of G2 Moderate Storms,” states the UK Met Office’s Space Weather forecast . “These most likely with any following magnetic cloud, with the risk continuing into day 4 (01 Jul).”

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 aurora displays 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.