Topline
The Northern Lights may be visible in the U.S. overnight on Wednesday and Thursday just as the Milky Way appears in the night sky. The delayed arrival of a coronal mass ejection traveling towards Earth may cause a geomagnetic storm, according to the latest forecast by the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center. It follows a false alarm on July 1-2, but also notable displays of aurora in northern U.S. states in recent weeks.
Key Facts
NOAA’s three-day forecast includes a minor geomagnetic storm, measured at a value of G1 on a scale of G1 to G5. According to NOAA’s forecast, the Kp index — which provides a rough guide to the intensity of aurora displays — may reach 5.
The G1 geomagnetic storm is forecast to peak in the evening hours of Wednesday, July 2. Although it’s subject to change, the forecast means the geomagnetic storm may be occurring as darkness falls in the U.S.
“G1 (Minor) geomagnetic storming is likely 02-03 July due to the CME effects” stated NOAA on X (Twitter). An Earth-directed coronal mass ejection — a cloud of super-charged particles released by the sun — left on June 28.
On Wednesday, the moon will have reached its bright first quarter phase, so aurora chasers will have to contend with some natural light pollution. Since the solstice occurred only two weeks ago, it doesn’t get completely dark at night in late June near the U.S.-Canada border (and not at all in Alaska).
The Northern Lights are caused by the solar wind, a stream of charged particles from the sun interacting with Earth’s magnetic field. Charged particles accelerate along the magnetic field lines toward the polar regions, where they collide with oxygen and nitrogen atoms, exciting them and causing them to release energy as light.
Where To See The Northern Lights
NOAA’s aurora viewlines indicate potential aurora displays are possible in northern U.S. states and Canada. U.S. states that may see aurora include (northerly parts of) Washington, northern Idaho, Montana, Wyoming, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, Iowa, New York, Vermont, New Hampshire and Maine. In the U.S., regions close to the Canadian border will have the highest chance.
When To See The Northern Lights
When and where aurora is visible is uncertain until a turbulent solar wind is detected by NASA’s DSCOVR and ACE satellites. Orbiting the sun from around a million miles from Earth, they give a roughly 30-minute warning of aurora displays after measuring the solar wind’s speed and magnetic intensity. Check NOAA’s 30-minute forecast or use the Glendale App for up-to-the-minute forecasts. Be prepared to fail — it may take multiple trips to finally see aurora, as displays can be unpredictable.
The Milky Way In June
Early July is a great time to see the Milky Way. Although it’s visible from the Northern Hemisphere all year, its bright core only becomes visible in the southern sky after dark from late May through September. The bright core is the center of the galaxy, home to a dense concentration of stars, star clusters and nebulae. You’ll need to be away from light pollution to see it.