Northern lights possible in much of Alaska through Sunday night, if the clouds cooperate

A minor geomagnetic storm that began Saturday is expected to keep northern lights possible across much of the state into Sunday night. Clouds could hide them in most places.

NOAA's Space Weather Prediction Center recorded storm levels Saturday and expects them again Sunday, with a chance of a stronger, moderate storm. Its latest forecast calls for storm levels through much of Sunday, peaking from about 3 to 6 pm Alaska time, then dipping before returning from 9 pm to midnight. It expects activity to ease Monday.

The early window falls mostly in daylight and twilight. Civil twilight ends around 5:30 pm in Anchorage and Wasilla and about 5 pm in Tok, with full dark roughly an hour later. That makes the 9 pm to midnight window the likelier one for most viewers.

The storm is coming from a coronal hole, an opening in the sun's outer atmosphere that sends out a fast stream of solar wind. Over the past day, it pushed solar wind speeds from about 425 to about 736 kilometers per second, NOAA said.

At the storm's expected peak, the aurora typically reaches as far south as Anchorage and Juneau. In Tok, the lights can appear overhead or high in the sky. In Glennallen, Wasilla and Anchorage, which sit near the southern edge, viewers should look for a glow low on the northern horizon.

Clouds are the biggest question. National Weather Service forecasts call for mostly cloudy skies across much of the state Sunday evening. Anchorage, Wasilla and Soldotna are forecast around 60% to 70% cloud cover, Glennallen 75% to 80% and Fairbanks and Tok 80% to 95%. Juneau is expected to see rain. For the rest of Saturday night, Glennallen and Anchorage have the clearest forecasts of the places we checked, at about half cloud cover through midnight, though activity is expected to drop a notch.

The usual advice applies: get away from town lights, find an open view to the north and head for higher ground. Near Anchorage, guides name Glen Alps Overlook at the end of Toilsome Hill Drive, Point Woronzof, and the Eklutna Tailrace and Knik River Valley, where Visit Anchorage says no mountains block the northern horizon. In the Mat-Su, guides name the viewing tower at Reflections Lake on the Palmer Hay Flats, Hatcher Pass, Willow and Big Lake. Around Glennallen and Tok, the general rule is a pullout with a clear view north, away from highway lights.

No forecast is a guarantee. The aurora brightens only when the magnetic field in the solar wind turns southward and stays there, which NOAA can't predict hours ahead, and a coronal hole stream can arrive weaker than expected. Check NOAA's 30-minute aurora forecast and a webcam or satellite view before driving anywhere.

A week earlier, another minor storm was forecast to bring northern lights to Fairbanks and Nome.