Solar Fireworks Alert: G2 Storm to Light Up Skies on April 16
A G2 – Moderate geomagnetic storm watch is in effect for April 16, 2025, triggered by a dramatic coronal mass ejection (CME) unleashed during a filament eruption on April 13. The Sun is keeping us on our toes, with moderate solar activity expected through April 15 and a chance for dazzling auroras by midweek. Buckle up for a wild ride through the solar system's latest antics!
Over the past 48 hours, our star has been anything but quiet. Two filament eruptions rocked the solar surface, each sending plumes of plasma into space. The first, a 20-degree-long filament centered near S20E20, began erupting after 21:30 UTC on April 12. Hot on its heels, a second, 12-degree filament near S22W09 blew its top after 05:00 UTC on April 13. Both events were captured in stunning detail by NASA's Solar Dynamics Observatory (SDO) and coronagraph imagery from the ESA/NASA SOHO spacecraft.
The second eruption stole the spotlight. Analysis of the resulting CME revealed an Earth-directed component, with models forecasting its arrival around midday on April 16. This incoming cloud of charged particles is what's driving the G2 storm watch, promising a geomagnetic rumble that could spark auroras as far south as the northern U.S. states, from New York to Idaho. While the impacts are expected to be moderate—think minor power grid hiccups or slight satellite disruptions—the auroral displays could be a stargazer's dream.
So, what's fueling this solar drama? The Sun's Region 4055 is the main character in this cosmic saga. This active region has been flexing its magnetic muscles, with a slight chance of producing X-class flares—the most powerful kind—on April 14 and 15. By April 16, as Region 4055 rotates toward the Sun's western limb, flare activity is expected to simmer down to low levels, though M-class flares remain likely. These flares, while less intense, can still pepper Earth's magnetosphere with high-energy particles, adding to the geomagnetic buzz.
The solar wind has been a key player too.
Over the past 24 hours, Earth has been bathed in enhanced solar wind from a negative polarity coronal hole high-speed stream (CH HSS). This stream has kept the geomagnetic field at quiet to active levels, with wind speeds easing from 465 km/s to around 435 km/s. The magnetic field strength hovered between 3–8 nT, with the Bz component—a critical factor in geomagnetic storms—fluctuating between -6 and +4 nT. For now, the solar wind's influence is waning, but the stage is set for a major shake-up when the April 13 CME arrives.
What can we expect when it hits? By mid to late April 16, the geomagnetic field could ramp up to G1 – Minor or G2 – Moderate storm levels. This means auroras might dance across high-latitude skies, potentially visible in places like Canada, Scandinavia, and the northern U.S. Beyond the light show, there's a small chance of weak power grid fluctuations or minor satellite issues, though nothing catastrophic. The real story here is nature's fireworks, not doom and gloom.
Meanwhile, the Sun's particle output is keeping space weather forecasters busy. The greater than 2 MeV electron flux at geostationary orbit spiked to high levels in the 24 hours leading up to 00:30 UTC today, and it's expected to stay moderate to high through April 15. There's even a slight chance of an S1 – Minor solar radiation storm on April 14 or 15, courtesy of Region 4055's flare potential. The greater than 10 MeV proton flux, however, remains at background levels, so no major radiation concerns for now.
Looking at the bigger picture, the Sun's activity is part of its 11-year solar cycle, and we're currently near the peak of Solar Cycle 25. Sunspots, like those dotting the solar disk on April 14, are magnetic hotspots that drive flares, CMEs, and filament eruptions. Images from NASA's SDO show Region 4055 as a sprawling cluster of dark patches, a testament to the Sun's restless energy.
As we count down to April 16, the solar wind environment will likely stay under the fading influence of the CH HSS through April 15. Quiet to unsettled conditions are expected, with occasional active periods. But all eyes are on the CME's arrival, which could jolt the geomagnetic field and ignite those auroras. The SWPC's Enlil model, a go-to tool for CME forecasting, predicts a direct hit, reinforcing the G2 storm watch.
For space weather enthusiasts, this is prime time to dust off your cameras and head north. The auroras, if they materialize, could be a breathtaking reward for braving the chilly April nights. Stay tuned to space weather updates, and keep an eye on the skies—our Sun is putting on a show, and you won't want to miss it!
Founder and chief forecaster of the Pogodnik service. He has many years of experience in the meteorological service. He is the author of numerous scientific publications and popular articles about the weather.
