“I would not drive out of my way for this particular event,” said Terry Onsager, a physicist at NOAA’s Space Weather Prediction Center, which issued the geomagnetic storm watch.
There are several reasons that Saturday’s possibility of seeing the northern lights might be, as Mr. Onsager put it, a “dud.”
He said a chunk of the sun’s atmosphere blasted off and began hurtling toward Earth this week. It is expected to hit the planet’s magnetic field on Saturday, which would produce the colorful glow of aurora borealis.
But based on the center’s measurements, that chunk of the sun’s atmosphere is supposed to arrive at 11 a.m. Eastern, Mr. Onsager said. The northern lights are visible only at night.
There is uncertainty in that prediction. The piece of the sun’s atmosphere could even miss the Earth entirely, negating any possibility of the northern lights. But it could arrive later in the day, or its effects could linger for hours, leaving the chance open for a nighttime viewing.
Enter another problem: the weather. To see the northern lights, one needs a clear, dark sky. Unfortunately, cloud cover is expected in many parts of the Northeast, said Ben Gelber, a meteorologist with NBC4 in Columbus, Ohio.
There will also be a nearly full moon to further obscure the sky, Mr. Gelber said.
“We have to be realistic,” Mr. Gelber said. “We have to dampen expectations, to be honest.”
The northern lights are not that uncommon, even in the 48 contiguous states, said Larry Lyons, a professor at the University of California, Los Angeles who studies space physics and the auroras.
The northern lights are probably visible about 10 times a year in parts of New York, Mr. Lyons estimated, away from the light pollution of major metropolitan areas.
“People in the northern states, when it’s clear, see it a few times a year,” he said. “It’s not that unusual.”
There are particularly higher chances during peaks of the solar cycle, which happen every 11 years, when the sun ejects larger pieces of its atmosphere, Mr. Onsager said. The last peak was around 2013 or 2014.
Still, having all the conditions right — good weather, clear skies, low light pollution and the right solar and electromagnetic conditions — is rare enough that it is worth checking the sky on Saturday night. (Or at least a NOAA website for any update on the possible geomagnetic storm.)
“There’s always a remote chance,” Mr. Gelber said. “You don’t want to close the window and figure out the sky’s breaking at the right time.”