Between the late evening of Thursday, June 4 and the early hours of Friday, June 5, 2026 , a new episode of aurora borealis visible also from Italy could occur. Space weather forecasts indicate the arrival of a cannibal CME, a particular coronal mass ejection which, by colliding with the Earth’s magnetic field, can generate geomagnetic storms of strong intensity.
Read more Dockworkers, the Istanbul manifesto
Experts’ estimates: G3 or G4 storms
According to data reported by spaceweatherlive.com, the impact of the solar plasma flow should produce magnetic conditions classified as G3 (strong) or even G4 (severe). The kP index, which measures geomagnetic activity, is expected around a value of 7 out of 9 from 18:00 UTC (20:00 Italian time), with a peak expected around 02:00. Values of this level can make auroras observable even at mid-latitudes, therefore potentially over our country, provided the sky is dark and cloudless.
What is a cannibal CME and why is it so powerful
CMEs are enormous quantities of plasma and magnetic fields ejected from the solar corona, often following flares generated by particularly unstable sunspots. In this case, the activity is linked to active region AR 4455, which in recent days has produced several X and M class flares, including an X1.07 recorded in the early afternoon of June 3. So-called cannibal CMEs form when a faster ejection catches up with and engulfs a previous slower one, creating a single, much more energetic structure. NASA emphasizes that this type of phenomenon can significantly amplify geomagnetic activity.
International forecasts
Astrophysicist Tony Phillips, curator of spaceweather.com, explained that the CME impact could generate storms capable of making auroras visible in Europe and North America. In the past, under similar conditions, the phenomenon has been observed with the naked eye in over 25 US states. The NOAA Space Weather Prediction Center forecasts G3 level geomagnetic storms, leaving open the possibility that the actual activity could exceed estimates.
Read more Weddings in Tuscany, loan boom: highest figures in Florence – How much does it cost to get married
How auroras form
Auroras are born when charged particles from the solar wind interact with atoms present in the Earth’s ionosphere. The released energy produces the typical luminous bands that arrange themselves along the magnetic field lines, creating the famous colored “curtains”.
Observing it from Italy: practical tips
To increase the chances of sighting, Phillips suggests moving away from artificial lights and looking for areas with clear, dark skies. A camera with a long exposure can help capture the phenomenon even when it is not very evident to the naked eye.
A fascinating phenomenon, but not without risks
Although the aurora is spectacular, more extreme geomagnetic storms – such as G5 level ones – can cause problems for electrical infrastructure, satellites, and communications. For tonight, however, such extreme conditions are not expected.
Read more Weather in Tuscany, more rain coming: what the forecasts say until Sunday