A magnetic storm forecast has been published for November 11-12, 2025: G3-G4 storms are possible.

The results of repeated calculations confirm the arrival of two solar plasma ejections from the high-level solar flares that occurred on November 9 and 10, reaching Earth today, at the junction of November 11 and 12. Current forecasts are similar to those of the middle of last week, when the strongest geomagnetic event of the year was expected on November 7. However, back then, the plasma clouds only skimmed the planet, triggering three-day G2-G3 storms that were weaker than predicted. In the current situation, a more intense, near-frontal event is expected, although the central, densest portions of the plasma ejections are expected to be offset by 10-15 degrees from the direction toward Earth, which will partially mitigate the impact on the magnetosphere.

Since the ejection from the second flare that occurred yesterday is much faster, it remains uncertain whether it will overtake the plasma cloud ejected a day earlier on its way to Earth. If so, a single cloud with an especially high density and a greatly enhanced magnetic field will approach the planet on the night of November 12th. Model calculations indicate that there will still be a gap of several hours between the two impacts. The impact of the first event could begin as early as today between 6:00 and 8:00 PM Moscow time, triggering G1-G2 storms and intense auroras in the Earth's eastern hemisphere. The second, most powerful cloud will strike the planet during the night or early morning of the 12th, creating a peak of magnetic storms in the G3-G4 range.

So far this year, G4 storms have been observed twice: on January 1st, when, understandably, they went virtually unnoticed, and on June 1st, amid a frontal impact on Earth from a large solar prominence ejected from the Sun. Storms of the highest level, level 5, last occurred in May 2024 (at that time, the first in 20 years). In relation to the current event, the possibility of it reaching the highest G5 level, however, is not considered at all and could arise only in an exceptional case, if the first actual strike, expected this evening, immediately shows a strong excess over the forecast.