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The northern lights may appear in up to 10 states Saturday night, according to a forecast from the National Ocean and Atmospheric Administration, which is predicting a full weekend of fair to strong auroral activity.
Northern lights over a camper's tent north of San Francisco in Middletown, California
A Kp index of four has been forecast for Saturday night, indicating an increase in auroral activity that “can be quite pleasing to look at” for observers in the right areas.
NOAA said in its outlook that minor geomagnetic storms, which contribute to increases in auroral activity, are likely on Saturday.
Saturday’s curved viewing line reaches as far south as central South Dakota, though chances of seeing the northern lights will increase the farther north observers are from it.
People who fail to catch a glimpse of aurora borealis Saturday night should consider trying again Sunday, when auroral activity is expected to increase alongside a Kp index of five—though it should be noted aurora forecasts are subject to change every few hours.
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States and areas encompassed by Saturday's viewing line include a majority of Alaska, northern Washington, northern Idaho, Montana, North Dakota, the northern half of South Dakota, Minnesota, Wisconsin, northern Michigan and the northern tip of Maine.
Saturday's viewing line.
Generally, the window of time between 10 p.m. and 2 a.m. provides the best conditions for northern lights viewing. Observers should also try to go to areas with little to no light pollution and clear skies. High vantage points can also help.
Traditional camera users should use tripods, wide-angle lenses and low apertures when snapping photos of the northern lights. Smartphone users should avoid using flash and use night mode on their cameras if possible.
NOAA and NASA are expecting more visible northern lights showings in the U.S. through early next year, citing a “solar maximum” reached on the sun’s surface that signifies peak levels of solar activity and sunspots. The increase in solar activity is capable of producing more solar flares that contribute to brighter northern lights appearances.
Get Ready For 50 Years Of Intense Northern Lights, Scientists Say (Forbes)