(NEXSTAR) — Parts of the U.S. may get the chance to see the northern lights for a second night in a row on Wednesday — as long as the conditions are right.

Since Sunday, NOAA's Space Weather Prediction Center had been tracking coronal mass ejections, or CMEs, hurled out by the sun. On Tuesday, the SWPC said a shock associated with one or both CMEs it detected had arrived.

That helped spur a forecast giving several northern states a chance at seeing the aurora Tuesday night.

The associated geomagnetic activity also prompted an infrequent but not uncommon G3 geomagnetic storm watch for Wednesday. As of 10:30 a.m. ET, the SWPC is showing Kp indexes — used to measure the strength of geomagnetic activity — in G3........

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