Minor geomagnetic storm could bring northern lights to Fairbanks and Nome Saturday night

NOAA's Space Weather Prediction Center forecasts a minor geomagnetic storm for Halloween night, Saturday, Oct. 31, strongest from 7 to 10 pm Alaska time. If it arrives as forecast, Fairbanks and Nome have the best chance of seeing the northern lights among six Alaska communities checked against NOAA and National Weather Service forecasts. It may not happen: forecasts are revised, and storms can arrive early, late or weaker than predicted.

The center's three-day forecast, issued 4:30 am Saturday, puts the planetary K index, a measure of magnetic disturbance, at 4.67 during the peak, the low end of the G1, or minor, category. The center issued a G1 watch Thursday for Saturday and Sunday, attributing the activity to fast solar wind from a coronal hole rather than a coronal mass ejection.

At this level, the aurora typically reaches Fairbanks, the Interior and the Arctic. From Fairbanks and Nome it would be overhead or high in the sky, not only low on the horizon. Anchorage, Juneau and Ketchikan sit south of that reach and are unlikely to see it unless the storm comes in stronger than forecast.

Nome has the clearest skies, with 27% to 33% cloud cover. Fairbanks sits near 53% during the peak, improving to 39% from 10 pm to 1 am, when activity is forecast to be somewhat weaker, before returning to 53%. Utqiagvik, though within reach, faces 92% to 94% overcast all night. Anchorage is forecast at 62% to 71%, Juneau at 87% to 95% and Ketchikan near 85%.

The University of Alaska Fairbanks Geophysical Institute says the aurora can be seen once civil twilight ends, about 6:30 pm in Fairbanks and 7:40 pm in Nome. The moon, about 65% lit, rises around 9:25 pm in Fairbanks and 10:50 pm in Nome, after the peak window there, and should not wash out a display of this strength.

The institute's recommended Fairbanks-area sites include Chena Lakes and Tanana Lakes recreation areas, Cleary Summit, Ester, Wickersham and Murphy domes, and Haystack Mountain on the Elliott Highway. In Nome and elsewhere, viewers should get away from town lights, find an open view to the north and seek higher ground.

NOAA's 30-minute aurora forecast, which shows where the aurora is in near real time, is the page to check before heading out.