The northern lights could be a lot farther south tonight

The northern lights might show up a lot farther south tonight, tomorrow, and Friday, perhaps even near you.

A geomagnetic storm is brewing, and it could form auroras over parts of Canada and the northern parts of the continental United States. Oregon, Iowa, Pennsylvania, and New York could all see shimmering skies after dusk. It’s the product of some recent rare and unusual weather in space.

Aurora forecast map for August 17, 2022
Aurora forecast map for August 17, 2022
Auroras are expected to form further south than usual as a geomagnetic storm arrives on August 17.
NOAA Space Weather Prediction Center

NOAA’s Space Weather Prediction Center (yes, that’s a thing) issued a geomagnetic storm watch from August 17 to August 19 “due to coronal high speed stream (CH HSS) and coronal mass ejection (CME) influences” with the potential to escalate to G3 conditions.

Okay, now let’s unpack that.

This all began a few days ago, 93 million miles away, on the sun. A coronal mass ejection is a large burst of magnetized plasma from the sun’s corona, its outermost layer. Scientists recently detected two of these CMEs erupting on the sun and heading toward Earth. They’re expected to arrive on August 18.

The two bursts may combine en route and create a geomagnetic storm reaching G3, or “strong” levels. That means it may create auroras not just at the poles but also closer to the equator than usual.

Auroras form when high-energy particles from the sun collide with the Earth’s atmosphere. These particles excite the gases in the sky and cause them to glow, similar to how neon lights work. Auroras are one of the few ways we can see space weather from the ground, and while they’re usually confined to the poles, enough excitement from the sun can create auroras much further away.

But before the CMEs get here tomorrow, a coronal hole high-speed stream is expected to arrive tonight and drive a G1, or “minor,” geomagnetic storm. A coronal hole is a cooler area in the sun’s corona that can generate high-speed solar wind full of charged particles and spread them out across the solar system. Coronal hole high-speed streams can also generate auroras on Earth.

Forecasters expect G2 or “moderate” storm activity to persist on August 19.

NOAA warns that geomagnetic storms can be disruptive if they become severe. “Geomagnetic storms can impact infrastructure in near-Earth orbit and on the surface, potentially disrupting communications, the electric power grid, navigation, radio, and satellite operations,” according to an NOAA press release.

The upcoming storms are not expected to cause much technical trouble. Even so, it might be a good opportunity to put all your electronics away for a few hours and just look up. You might just see the sky light up.

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