Aurora alert: Moderate geomagnetic storm could bring northern lights as far south as New York this weekend

Northern lights appear as ribbons of purple and pink light with some green lower down on the horizon across the sky. stream from a geyser rises up in the foreground. .

The sun has been putting on quite a show this week, sparking impressive auroras across the U.S. and Canada, and it isn't finished yet. 

Continued solar activity has prompted the National Oceanic and Atmospheric (NOAA) Space Weather Prediction Center (SWPC) to issue a geomagnetic storm warning for Aug. 3 and Aug. 4 which is great news for those wishing to see the northern lights. 

The geomagnetic watch was issued in anticipation of the arrival of a coronal mass ejection (CME) associated with a powerful M.8-class solar flare that erupted from the sun on Aug. 1. If the predicted moderate G2 conditions are reached we could witness auroras as far south as New York and Idaho. 

CMEs are expulsions of plasma and magnetic fields from the sun. They carry electrically charged atoms known as ions. When CMEs collide with Earth's magnetosphere, they can cause geomagnetic storms. During such storms, the ions interact with gases in Earth's atmosphere, emitting energy as light. This light display is called the northern lights, or aurora borealis, in the Northern Hemisphere, and the southern lights, or aurora australis, in the Southern Hemisphere.

NOAA classifies geomagnetic storms using a G-scale that measures their intensity, ranging from G1 for minor storms to G5 for the most extreme ones. Moderate G2 conditions are predicted for the weekend which means we could be in for quite the aurora show as the previous "minor" G1 conditions on July 29/30 sparked dazzling northern lights across the U.S. and Canada.

Northern light above central Alberta, Canada on July 30, 2024 during the minor G1 geomagnetic storm. (Image credit: Theresa Tanner/Dar Tanner)

Similar to Earth's weather, space weather is unpredictable and challenging to forecast. Geomagnetic storm warnings are common, and sometimes, they amount to nothing. As the weekend approaches, space weather forecasters will have a clearer understanding of when, or if, the CME will arrive.

Geomagnetic storm watch issued by NOAA's Space Weather Prediction Center. (Image credit: NOAA Space Weather Prediction Center)

But remember, even if Earth is hit by the CME, depending on the magnetic field alignment within the CME it could connect with Earth's magnetosphere causing impressive northern lights displays or our planet could "close the door" on the CME, leaving aurora chasers in the dark. When checking out space weather data from resources such as Space Weather Live, keep an eye on the Interplanetary Magnetic Field (IMF), particularly the Bz value which is the north-south direction of the IMF. The Bz needs to be orientated southward for a successful connection to Earth's magnetosphere which points northward, according to Space Weather Live. 

To keep up to date with the latest space weather alerts and forecast check out NOAA's Space Weather Prediction Center. I also recommend checking out space weather physicist Tamitha Skov's account on X and YouTube channel for detailed space weather reports and valuable aurora hunting information. 

Editor's note:  If you capture a stunning photo or video of the northern lights (or southern lights!) and want to share them with Space.com for a possible story, send images, comments on the view and your location, as well as use permissions to spacephotos@space.com.