Aurora possible across 19 U.S. states Monday night

A coronal mass ejection (CME) that left the Sun late on June 26 is forecast to arrive early on June 30, potentially producing a G1-G2 geomagnetic storm. Space-weather models from NASA, NOAA and the UK Met Office indicate the disturbance could make aurora visible along the U.S.–Canada border, especially in Montana, North Dakota, Minnesota and northern Wisconsin.

The storm is not expected to be a major aurora event, but KP-4 or KP-5 conditions sometimes allow the northern lights to be seen from the far-northern tier of the United States. Clear, dark skies and a northward view are recommended; cameras with long-exposure settings may capture faint displays before they become visible to the eye.

Experts note that long daylight hours after the recent solstice and the rise of the full Strawberry Moon may make the aurora harder to spot. In addition to the four states with the highest likelihood, observers in Washington, Idaho, South Dakota, Michigan, Maine and parts of Oregon, Wyoming, Nebraska, Iowa, Illinois, Indiana, Ohio, New York, Vermont and New Hampshire also have a modest chance.

"Enhanced conditions are expected to return early to mid on 30 Jun due to the CME that left the Sun late on 26 Jun," NOAA space-weather forecasters said.

"CME arrival on day 3 is expected to increase activity to Active to G1 Minor Storms with a chance of G2 Moderate Storms," the UK Met Office warned.

Space-weather forecasts are subject to rapid updates as conditions evolve.