Northern lights could be visible in these states: See forecast map

More than a dozen states in the northern part of the contiguous U.S. have a chance to see the northern lights.

About 15 states could catch a glimpse of the aurora borealis on Aug. 9, according to the latest forecast from the National Oceanic and Atmospheric Administration's Space Weather Prediction Center.

An earlier forecast for Friday, Aug. 8, showed a possibility of seeing the aurora in about 18 states was downgraded to a lesser event shorter before 8 a.m. ET.

A coronal mass ejection, or large expulsions of plasma and magnetic field from the sun, lifted off the star on Aug. 5, raising expectations to cause geomagnetic activity, according to NOAA.

For Aug. 9, NOAA said it predicts a geomagnetic K-index of 5. The K-index measures geomagnetic activity and indicates how far away from the poles the northern lights could be visible, according to the agency. A Kp score between 3-5 indicates brighter and increased activity, per NOAA.

On another geomagnetic storm scale, NOAA ranks the event a G1, which is considered a minor event.

The northern lights, a natural phenomenon formally known as the aurora borealis, can project colorful lights in the night sky because of an interaction between the sun's plasma and Earth's magnetic field, according to the National Weather Service.

When could the northern lights be visible?

The best view of the northern lights is usually within an hour or two of midnight, according to NOAA.

The aurora is not visible during daylight hours, and is usually seen just after sunset or just before sunrise, according to the agency.

Where could the northern lights be visible? See map

Parts of about 15 states are within NOAA's forecasted "view line" for the northern lights on Aug. 9. The view line indicates the southernmost point where the aurora could be seen on the northern horizon.

The following states could catch a glimpse of the aurora, according to NOAA's forecasted view line:

• Alaska

• Idaho

• Iowa

• Maine

• Michigan

• Minnesota

• Montana

• New Hampshire

• New York

• North Dakota

• South Dakota

• Vermont

• Washington

• Wisconsin

• Wyoming