What to know about seeing the northern lights from WA

Will we get to see the northern lights this week from Washington?

Earlier this week, a University of Alaska aurora forecast, using data from the National Oceanic and Atmospheric Administration, showed 17 states — including all of Washington — would be able to see the northern lights Thursday.

The forecast has since changed, and the audience of the aurora will now be much smaller than some early forecasts suggested, although it is expected to include the northern horizon of Washington.

The Geophysical Institute at the University of Alaska Fairbanks forecasts “active auroral displays” that should dance low across the horizon Friday and Saturday night along the states bordering Canada. It will be “a faint glow,” though, said Bryan Brasher, a project manager at the NOAA’s Space Weather Prediction Center.

The last time the aurora stretched down to Washington in April, it was — of course — cloudy in Seattle. But Mother Nature will grant us clear night skies this week as the solar storm whips through the upper atmosphere, lighting up the northern horizon in a faint red and green glow.

Even with clear skies, the aurora can be difficult to see if you’re in the middle of a city like Seattle. The closer you can get to dark skies and away from a source of light pollution, the better.

Auroral activity has also been forecast for parts of Canada, including Vancouver.

The glow of the aurora is produced when particles from the sun’s magnetic field are blasted into space, eventually colliding with oxygen and nitrogen atoms and molecules in Earth’s upper atmosphere, according to the Space Weather Prediction Center.

The Kp-index, or planetary index, which is a system of measuring aurora strength running from 0 to 9, will be at 4 on Friday and 5 on Saturday in North America, according to the Geophysical Institute.

A Kp in the range of 3 to 5 means an aurora will be “quite pleasing to look at,” if you’re in the right place, according to the National Weather Service. Any occurrence above 5 is considered a geomagnetic storm.

The aurora typically stretches into only Alaska, Canada and Scandinavia, but an 11-year solar cycle expected to peak in 2024 is making the glow visible in places farther to the south. Three months ago, the light displays were visible in Arizona, marking the third severe geomagnetic storm since the current solar cycle began in 2019, according to The Associated Press.

“Although predicting these events beyond a few days can be challenging, we can confidently say that with solar maximum approaching, more captivating displays of auroras are undoubtedly on their way,” Brasher said.

The initial confusion of how far the aurora would stretch was caused by the recurrence of a particular coronal hole, or a temporarily cool area on the sun where solar particles can escape. The hole had caused elevated geomagnetic activity when the sun had last rotated toward Earth last month, Brasher said.

Experts had predicted a geomagnetic storm would occur once again, 27 days after the initial geomagnetic activity — this Thursday — but as the coronal hole faced Earth once again, “it was clear that it had diminished, and we adjusted our forecast accordingly,” Brasher said.

The Geophysical Institute had originally forecast a Kp of 6 Thursday night, but even then, “it would still be unlikely to cause the aurora to be seen from midlatitude states,” Brasher said.

Both light pollution and cloud cover impact the ability to see the aurora in action in Washington.

Friday and Saturday night are expected to be clear across Western Washington, according to the weather service, and at less than 10% full, the waning crescent moon won’t provide too much light disruption.

The aurora will be strongest in the northeast corner of Washington, but anyone in the state outside of a city should have a good opportunity to see it by looking toward the northern horizon, according to the Geophysical Institute’s forecast.

The Space Weather Prediction Center anticipates the best viewing times for those in range are between 10 p.m. and 2 a.m.