An intense solar storm impacting Earth could send the aurora, also known as Northern Lights, deep into the southern United States over the next 48 hours while setting the stage for potential damage to electrical systems and electronics on Earth. Due to the threat. the National Weather Service’s Space Weather Prediction Center has issued a Geomagnetic Storm Watch for a SEVERE storm ranked a 4 out of 5 on their geomagnetic storm watch magnitude chart.
“Geomagnetic activity can vary considerably during storm progression with intermittent periods of escalation or weakening as a CME passes over Earth,” wrote the SWPC in an update today.
This is a very significant space weather event with peak impacts possible on June 2. https://t.co/DbhyFf2h23
— the Weatherboy (@theWeatherboy) May 31, 2025
Coronal Mass Ejections (CMEs) are large expulsions of plasma and magnetic field from the Sun’s corona. They can eject billions of tons of coronal material and carry an embedded magnetic field, frozen in flux, that is stronger than the background solar wind interplanetary magnetic field (IMF) strength. CMEs travel outward from the Sun at various speeds, with some reaching the Earth as quickly as 15-18 hours and others requiring days to arrive. According to the SWPC, CMEs expand in size as they propagate away from the Sun and larger ones can reach a size comprising nearly a quarter of the space between Earth and the Sun by the time it reaches our planet.
“Despite the total magnetic field strength currently at near 4x normal, the orientation has trended north –less favorable for enhanced geomagnetic conditions. Should the orientation shift south (opposite Earth’s) activity could escalate quickly,” the SWPC warns.
Geomagnetic storms are rated on a 1-5 scale by the SWPC, with 1 considered minor and 5 considered extreme. Geomagnetic storms can disrupt electronics and electrical systems, interfere with spacecraft and satellite communication, and also trigger brilliant displays of the aurora in the night sky. According to the SWPC, the current geomagnetic storm, which is forecast to become at least a G4 event, could allow for aurora to be visible in the pre-sunrise skies across much of the United States from Alabama to California and places north where clouds or light pollution won’t interfere with the view.
One frequent side effect of these geomagnetic storms is the presence of aurora. The probability and location of aurora displays is based on the Kp index of the storm. The K-index, and by extension the Planetary K-index, are used to characterize the magnitude of geomagnetic storms. The SWPC says that Kp is an excellent indicator of disturbances in the Earth’s magnetic field and is used by SWPC to decide whether geomagnetic alerts and warnings need to be issued for users who are affected by these disturbances. Beyond signifying how bad a geomagnetic storm’s impact can be felt, the Kp index can also help indicate how low, latitude-wise the aurora will be.
Aurora can appear and flicker at any time during the geomagnetic storm event; it may appear briefly and reappear with varying intensity and glow at any time at night during geomagnetic storms; there is no specific direction to look into or time to see them other than being in dark skies clear of clouds and light pollution.
As the CME interacts with Earth and its magnetosphere, a variety of things could unfold based on the amount of energy hitting and the angle it impacts the Earth. Power system voltage irregularities are possible and false alarms may be triggered on some protection devices. Minor impacts on satellite operations could also be possible, with intermittent satellite navigation (GPS) problems likely. Should the geomagnetic storm become stronger, aurora could be brighter and could appear even more south while impacts to electrical systems could be more severe.
“Infrastructure operators and authorities have been notified to take action to mitigate any possible impacts and (follow) situational awareness. Possible increased and more frequent voltage control problems –normally mitigable. Increased possibility of anomalies or effects to satellite operations. More frequent and longer periods of GPS degradation possible,” the SWPC said of today’s geomagnetic storm.
NOAA forecasters analyze a variety of solar data from spacecraft to determine what impacts a geomagnetic storm could produce. Analyzing data from the DSCOVER and ACE satellite is one way forecasters can tell when the enhanced solar wind from a coronal hole is about to arrive at Earth. A few things they look for in the data to determine when the enhanced solar wind is arriving at Earth:
• Solar wind speed increases
• Temperature increases
• Particle density decreases
• Interplanetary magnetic field (IMF) strength increases
While these solar events can help illuminate the sky with stunning aurora, they can also do considerable harm to electronics, electrical grids, and satellite and radio communications.
The 1859 incident, which occurred on September 1-2 in 1859, is also known as the “Carrington Event.” This event unfolded as powerful geomagnetic storm struck Earth during Solar Cycle 10. A CME hit the Earth and induced the largest geomagnetic storm on record. The storm was so intense it created extremely bright, vivid aurora throughout the planet: people in California thought the sun rose early, people in the northeastern U.S. could read a newspaper at night from the aurora’s bright light, and people as far south as Hawaii and south-central Mexico could see the aurora in the sky.
Image: NASA/Mary Pat Hrybyk-Keith
The event severely damaged the limited electrical and communication lines that existed at that time; telegraph systems around the world failed, with some telegraph operators reporting they received electric shocks.
A June 2013 study by Lloyd’s of London and Atmospheric and Environmental Research (AER) in the U.S. showed that if the Carrington event happened in modern times, damages in the U.S. could exceed $2.6 trillion, roughly 15% of the nation’s annual GDP.
While typically known for their weather forecasts, the National Oceanic and Atmospheric Administration (NOAA) and its National Weather Service (NWS) is also responsible for “space weather.” While there are private companies and other agencies that monitor and forecast space weather, the official source for alerts and warnings of the space environment is the Space Weather Prediction Center (SWPC). The SWPC is located in Boulder, Colorado and is a service center of the NWS, which is part of NOAA. The Space Weather Prediction Center is also one of nine National Centers for Environmental Prediction (NCEP) as they monitor current space weather activity 24/7, 365 days a year.
