Auroras Possible Tonight June 28-29 Across Northern U.S.

A small part of this coronal mass ejection on June 28 was directed toward Earth. Video from the Solar and Heliospheric Observatory

If you live in the northern U.S. and Canada and your sky is clear tonight, watch for the northern lights. A geomagnetic storm is in progress courtesy of a recent coronal hole (see this earlier post) and a grazing impact from a coronal mass ejection (CEM) launched by a modest solar flare Thursday.

The Kp index, indicator of magnetic activity high overhead, indicated a geomagnetic storm in progress around 8 p.m. CDT. Credit: NOAA

More importantly, the interplanetary magnetic field whirled out by the sun across the solar system has tipped southward, the ideal orientation to hook up with our planet’s own magnetic field and deliver solar particles to our upper atmosphere where they can spark auroras. With no moon, conditions are ideal for an aurora watch. Look to the north for any unusual streaks or glowing patches once it gets dark.

As of 8 p.m. the Kp index had risen to “5”, the threshold for a minor geomagnetic storm.

Update 11:30 p.m. CDT: Even higher activity reported with Kp = 6 (moderate storm). The auroral oval map, which shows the extent of the the northern lights, indicates the aurora is currently visible across the northeastern states (upper New York, Maine) and Upper Midwest. Cloudy here in Duluth, Minn.