Solar Storm Hits Earth: CME Triggers G1 Geomagnetic Storm, Auroras Possible

A minor but well-aimed coronal mass ejection from the Sun reached Earth on August 7, triggering a G1-class geomagnetic storm. NOAA and spaceweather.com confirmed the impact, with auroras visible in high-latitude regions including northern Michigan and Maine.

A coronal mass ejection (CME) that erupted from the Sun on Monday, August 3, reached Earth on Friday, August 7, triggering a G1-class (minor) geomagnetic storm, according to NOAA's Space Weather Prediction Center and spaceweather.com.

The CME was described as "minor but well-aimed" by spaceweather.com, which forecast the impact could spark auroras at high latitudes. NOAA's WSA-Enlil model confirmed the Earth-directed trajectory of the plasma cloud.

What Happened

CMEs are large explosions of charged plasma and magnetic fields from the Sun's corona. This particular CME traveled at moderate speed — taking roughly four days to cross the 150 million kilometers between the Sun and Earth. The fastest CMEs can make the journey in as little as 15 hours.

When CMEs slam into Earth's magnetosphere, they disturb the planet's magnetic field, causing geomagnetic storms classified on NOAA's G1 through G5 scale. G1 storms, like this one, typically cause weak power grid fluctuations and minor impacts on satellite operations.

Where to See Auroras

The storm energized nitrogen and oxygen particles in Earth's upper atmosphere, potentially producing northern lights visible in high-latitude regions. Forecasters predicted aurora visibility in areas like northern Michigan and Maine. G1 storms generally keep the light show confined to higher latitudes, unlike stronger G3-G5 events that can push auroras as far south as Illinois or Oregon.

Solar Activity Context

The Sun is currently near the peak of its 11-year solar cycle (Solar Cycle 25), which has produced more frequent flares and CMEs throughout 2026. Earlier this year, multiple G3 and G4 storms brought auroras to unusually low latitudes across the United States and Europe.

Skywatchers hoping to catch future displays should monitor NOAA's 3-day space weather forecast and the planetary K-index, which measures geomagnetic activity in real time. A Kp value of 5 or higher typically indicates visible auroras at mid-latitudes.

Sources: Starlust, Spaceweather.com