Several media reports, starting last week and citing a University of Alaska aurora forecast, had claimed that 17 states — including Maryland — could see the northern lights Thursday, but experts say that is unlikely given current conditions.
Murtagh said that the confusion may have started almost a month ago when a coronal hole, or a temporarily cool area on the sun where solar particles can escape, formed. Because of the sun’s rotation cycles, experts predicted a geomagnetic storm 27 days later — this Thursday. Space meteorologists expected that hole would lead to a Level 1 or Level 2 geomagnetic storm on a scale that goes up to 5, meaning a moderate storm at best. That could create a glow on the horizon in northern states, Murtagh said, but nothing major.
“There was never a big storm predicted to begin with,” he said. NOAA has not released a northern lights watch for Thursday, and Murtagh doesn’t expect significant viewing opportunities.
Research associate professor Don Hampton, a space physicist at the University of Alaska Fairbanks Geophysical Institute, released a statement Monday addressing auroral predictions “making the rounds.” He said his university doesn’t make long-term auroral predictions and that it had used data from the Colorado-based Space Weather Prediction Center, a part of NOAA.
He said that, like all data analysis, the accuracy of the models to predict the auroral activity strongly depends on the quality and amount of data analyzed.
“There are only a few satellites and instruments dedicated to collecting these data, so the models typically have a wide range of predictions since the observations are relatively sparse,” he said. “While large solar storms can be seen leaving the vicinity of the sun, and their direction and speed can be estimated, once they leave the local solar vicinity they cannot be tracked. During this time the solar storms can be slightly diverted or even reduced, and the final impact on Earth’s magnetic field may be different than predicted.”
What causes aurora?
Auroras happen during geomagnetic storms, when energy and particles from the sun disturb Earth’s magnetosphere. Some particles travel along Earth’s magnetic field lines into the upper atmosphere, where they excite oxygen and nitrogen molecules and release photons of light.
The storms themselves are caused by magnetic energy and electrons hurled into space by the sun. The stronger the solar storm, the greater the effect — especially if the outburst is directed toward Earth.
The northern and southern lights, collectively known as the aurora, are most common in the high Arctic and Antarctic regions around the poles, but they can venture to the middle latitudes on rare occasions during particularly strong geomagnetic storms.
Some reports last week predicted that northern lights might be seen across the country this Wednesday or Thursday, but meteorologists said it’s difficult to predict geomagnetic storms that far in advance.
It’s hard enough for meteorologists to correctly forecast terrestrial weather — now imagine predicting space weather.
“Forecasting them more than three days out is kind of like wishcasting,” said Chris Wicklund, a meteorologist in Minnesota. “I think a lot of people are going to be disappointed Thursday.”
In general, seeing the aurora borealis in the United States, especially in more southern states, requires little light pollution and clear, dark skies, often around midnight or 1 a.m., Wicklund said.
While viewing the northern lights this week is unlikely, Murtagh said that more significant geomagnetic storms, and as a result more viewable northern lights, could come in the next year or two.
There is an 11-year solar cycle that contains periods known as a solar minimum and solar maximum. During the minimum, there are few eruptions on the sun and consequently very few northern lights. During the maximum, there are more explosions and as a result much more aurora, Murtagh explained.
“We are now approaching the maximum,” he said. That could result in more “severe” geomagnetic storms, like those seen in March and April in Virginia, Arizona and North Carolina, among other southern states.
Kasha Patel contributed to this report.